Search results

Title: Cocaine-induced neurodevelopmental deficits and underlying mechanisms.
Creator: Martin, Melissa M, Graham, Devon L, McCarthy, Deirdre M, Bhide, Pradeep G, Stanwood, Gregg D
Abstract/Description: Exposure to drugs early in life has complex and long-lasting implications for brain structure and function. This review summarizes work to date on the immediate and long-term effects of prenatal exposure to cocaine. In utero cocaine exposure produces disruptions in brain monoamines, particularly dopamine, during sensitive periods of brain development, and leads to permanent changes in specific brain circuits, molecules, and behavior. Here, we integrate clinical studies and significance with...
Show moreExposure to drugs early in life has complex and long-lasting implications for brain structure and function. This review summarizes work to date on the immediate and long-term effects of prenatal exposure to cocaine. In utero cocaine exposure produces disruptions in brain monoamines, particularly dopamine, during sensitive periods of brain development, and leads to permanent changes in specific brain circuits, molecules, and behavior. Here, we integrate clinical studies and significance with mechanistic preclinical studies, to define our current knowledge base and identify gaps for future investigation. Birth Defects Research (Part C) 108:147-173, 2016. © 2016 Wiley Periodicals, Inc.
Show less
Date Issued: 2016-06-01
Identifier: FSU_pmch_27345015, 10.1002/bdrc.21132, PMC5538582, 27345015, 27345015
Format: Citation

Title: Prediction of individual differences in fear response by novelty seeking, and disruption of contextual fear memory reconsolidation by ketamine.
Creator: Duclot, Florian, Perez-Taboada, Iara, Wright, Katherine N, Kabbaj, Mohamed
Abstract/Description: Only a portion of the population exposed to trauma will develop persistent emotional alterations characteristic of posttraumatic stress disorder (PTSD), which illustrates the necessity for identifying vulnerability factors and novel pharmacotherapeutic alternatives. Interestingly, clinical evidence suggests that novelty seeking is a good predictor for vulnerability to the development of excessive and persistent fear. Here, we first tested this hypothesis by analyzing contextual and cued fear...
Show moreOnly a portion of the population exposed to trauma will develop persistent emotional alterations characteristic of posttraumatic stress disorder (PTSD), which illustrates the necessity for identifying vulnerability factors and novel pharmacotherapeutic alternatives. Interestingly, clinical evidence suggests that novelty seeking is a good predictor for vulnerability to the development of excessive and persistent fear. Here, we first tested this hypothesis by analyzing contextual and cued fear responses of rats selected for their high (high responders, HR) or low (low responders, LR) exploration of a novel environment, indicator of novelty seeking. While HR and LR rats exhibited similar sensitivity to the shock and cued fear memory retention, fewer extinction sessions were required in HR than LR animals to reach extinction, indicating faster contextual and cued memory extinction. In a second part, we found an effective disruption of contextual fear reconsolidation by the N-methyl-d-aspartate receptor antagonist ketamine, associated with a down-regulation of early growth response 1 (Egr1) in the hippocampal CA1 area, and up-regulation of brain-derived neurotrophic factor (Bdnf) mRNA levels in the prelimbic and infralimbic cortices. Altogether, these data demonstrate a link between novelty seeking and conditioned fear extinction, and highlight a promising novel role of ketamine in affecting established fear memory.
Show less
Date Issued: 2016-10-01
Identifier: FSU_pmch_27343386, 10.1016/j.neuropharm.2016.06.022, PMC5017153, 27343386, 27343386, S0028-3908(16)30275-1
Format: Citation

Title: An insight into the thermodynamic characteristics of human thrombopoietin complexation with TN1 antibody.
Creator: Arai, Shigeki, Shibazaki, Chie, Adachi, Motoyasu, Honjo, Eijiro, Tamada, Taro, Maeda, Yoshitake, Tahara, Tomoyuki, Kato, Takashi, Miyazaki, Hiroshi, Blaber, Michael, Kuroki, Ryota
Abstract/Description: Human thrombopoietin (hTPO) primarily stimulates megakaryocytopoiesis and platelet production and is neutralized by the mouse TN1 antibody. The thermodynamic characteristics of TN1 antibody-hTPO complexation were analyzed by isothermal titration calorimetry (ITC) using an antigen-binding fragment (Fab) derived from the TN1 antibody (TN1-Fab). To clarify the mechanism by which hTPO is recognized by TN1-Fab the conformation of free TN1-Fab was determined to a resolution of 2.0 Å using X-ray...
Show moreHuman thrombopoietin (hTPO) primarily stimulates megakaryocytopoiesis and platelet production and is neutralized by the mouse TN1 antibody. The thermodynamic characteristics of TN1 antibody-hTPO complexation were analyzed by isothermal titration calorimetry (ITC) using an antigen-binding fragment (Fab) derived from the TN1 antibody (TN1-Fab). To clarify the mechanism by which hTPO is recognized by TN1-Fab the conformation of free TN1-Fab was determined to a resolution of 2.0 Å using X-ray crystallography and compared with the hTPO-bound form of TN1-Fab determined by a previous study. This structural comparison revealed that the conformation of TN1-Fab does not substantially change after hTPO binding and a set of 15 water molecules is released from the antigen-binding site (paratope) of TN1-Fab upon hTPO complexation. Interestingly, the heat capacity change (ΔCp) measured by ITC (-1.52 ± 0.05 kJ mol(-1) K(-1) ) differed significantly from calculations based upon the X-ray structure data of the hTPO-bound and unbound forms of TN1-Fab (-1.02 ∼ 0.25 kJ mol(-1) K(-1) ) suggesting that hTPO undergoes an induced-fit conformational change combined with significant desolvation upon TN1-Fab binding. The results shed light on the structural biology associated with neutralizing antibody recognition.
Show less
Date Issued: 2016-10-01
Identifier: FSU_pmch_27419667, 10.1002/pro.2985, PMC5029525, 27419667, 27419667
Format: Citation

Title: An Mcm10 Mutant Defective in ssDNA Binding Shows Defects in DNA Replication Initiation.
Creator: Perez-Arnaiz, Patricia, Kaplan, Daniel L
Abstract/Description: Mcm10 is an essential protein that functions to initiate DNA replication after the formation of the replication fork helicase. In this manuscript, we identified a budding yeast Mcm10 mutant (Mcm10-m2,3,4) that is defective in DNA binding in vitro. Moreover, this Mcm10-m2,3,4 mutant does not stimulate the phosphorylation of Mcm2 by Dbf4-dependent kinase (DDK) in vitro. When we expressed wild-type levels of mcm10-m2,3,4 in budding yeast cells, we observed a severe growth defect and a...
Show moreMcm10 is an essential protein that functions to initiate DNA replication after the formation of the replication fork helicase. In this manuscript, we identified a budding yeast Mcm10 mutant (Mcm10-m2,3,4) that is defective in DNA binding in vitro. Moreover, this Mcm10-m2,3,4 mutant does not stimulate the phosphorylation of Mcm2 by Dbf4-dependent kinase (DDK) in vitro. When we expressed wild-type levels of mcm10-m2,3,4 in budding yeast cells, we observed a severe growth defect and a substantially decreased DNA replication. We also observed a substantially reduced replication protein A- chromatin immunoprecipitation signal at origins of replication, reduced levels of DDK-phosphorylated Mcm2, and diminished Go, Ichi, Ni, and San (GINS) association with Mcm2-7 in vivo. mcm5-bob1 bypasses the growth defect conferred by DDK-phosphodead Mcm2 in budding yeast. However, the growth defect observed by expressing mcm10-m2,3,4 is not bypassed by the mcm5-bob1 mutation. Furthermore, origin melting and GINS association with Mcm2-7 are substantially decreased for cells expressing mcm10-m2,3,4 in the mcm5-bob1 background. Thus, the origin melting and GINS-Mcm2-7 interaction defects we observed for mcm10-m2,3,4 are not explained by decreased Mcm2 phosphorylation by DDK, since the defects persist in an mcm5-bob1 background. These data suggest that DNA binding by Mcm10 is essential for the initiation of DNA replication.
Show less
Date Issued: 2016-11-20
Identifier: FSU_pmch_27751725, 10.1016/j.jmb.2016.10.014, PMC5115986, 27751725, 27751725, S0022-2836(16)30429-6
Format: Citation

Title: 14-3-3τ promotes surface expression of Cav2.2 (α1B) Ca2+ channels.
Creator: Liu, Feng, Zhou, Qin, Zhou, Jie, Sun, Hao, Wang, Yan, Zou, Xiuqun, Feng, Lingling, Hou, Zhaoyuan, Zhou, Aiwu, Zhou, Yi, Li, Yong
Abstract/Description: Surface expression of voltage-gated Ca(2+) (Cav) channels is important for their function in calcium homeostasis in the physiology of excitable cells, but whether or not and how the α1 pore-forming subunits of Cav channels are trafficked to plasma membrane in the absence of the known Cav auxiliary subunits, β and α2δ, remains mysterious. Here we showed that 14-3-3 proteins promoted functional surface expression of the Cav2.2 α1B channel in transfected tsA-201 cells in the absence of any known...
Show moreSurface expression of voltage-gated Ca(2+) (Cav) channels is important for their function in calcium homeostasis in the physiology of excitable cells, but whether or not and how the α1 pore-forming subunits of Cav channels are trafficked to plasma membrane in the absence of the known Cav auxiliary subunits, β and α2δ, remains mysterious. Here we showed that 14-3-3 proteins promoted functional surface expression of the Cav2.2 α1B channel in transfected tsA-201 cells in the absence of any known Cav auxiliary subunit. Both the surface to total ratio of the expressed α1B protein and the current density of voltage step-evoked Ba(2+) current were markedly suppressed by the coexpression of a 14-3-3 antagonist construct, pSCM138, but not its inactive control, pSCM174, as determined by immunofluorescence assay and whole cell voltage clamp recording, respectively. By contrast, coexpression with 14-3-3τ significantly enhanced the surface expression and current density of the Cav2.2 α1B channel. Importantly, we found that between the two previously identified 14-3-3 binding regions at the α1B C terminus, only the proximal region (amino acids 1706-1940), closer to the end of the last transmembrane domain, was retained by the endoplasmic reticulum and facilitated by 14-3-3 to traffic to plasma membrane. Additionally, we showed that the 14-3-3/Cav β subunit coregulated the surface expression of Cav2.2 channels in transfected tsA-201 cells and neurons. Altogether, our findings reveal a previously unidentified regulatory function of 14-3-3 proteins in promoting the surface expression of Cav2.2 α1B channels.
Show less
Date Issued: 2015-01-30
Identifier: FSU_pmch_25516596, 10.1074/jbc.M114.567800, PMC4317001, 25516596, 25516596, M114.567800
Format: Citation

Title: 14-3-3 protein targets misfolded chaperone-associated proteins to aggresomes.
Creator: Xu, Zhe, Graham, Kourtney, Foote, Molly, Liang, Fengshan, Rizkallah, Raed, Hurt, Myra, Wang, Yanchang, Wu, Yuying, Zhou, Yi
Abstract/Description: The aggresome is a key cytoplasmic organelle for sequestration and clearance of toxic protein aggregates. Although loading misfolded proteins cargos to dynein motors has been recognized as an important step in the aggresome formation process, the molecular machinery that mediates the association of cargos with the dynein motor is poorly understood. Here, we report a new aggresome-targeting pathway that involves isoforms of 14-3-3, a family of conserved regulatory proteins. 14-3-3 interacts...
Show moreThe aggresome is a key cytoplasmic organelle for sequestration and clearance of toxic protein aggregates. Although loading misfolded proteins cargos to dynein motors has been recognized as an important step in the aggresome formation process, the molecular machinery that mediates the association of cargos with the dynein motor is poorly understood. Here, we report a new aggresome-targeting pathway that involves isoforms of 14-3-3, a family of conserved regulatory proteins. 14-3-3 interacts with both the dynein-intermediate chain (DIC) and an Hsp70 co-chaperone Bcl-2-associated athanogene 3 (BAG3), thereby recruiting chaperone-associated protein cargos to dynein motors for their transport to aggresomes. This molecular cascade entails functional dimerization of 14-3-3, which we show to be crucial for the formation of aggresomes in both yeast and mammalian cells. These results suggest that 14-3-3 functions as a molecular adaptor to promote aggresomal targeting of misfolded protein aggregates and may link such complexes to inclusion bodies observed in various neurodegenerative diseases.
Show less
Date Issued: 2013-09-15
Identifier: FSU_pmch_23843611, 10.1242/jcs.126102, PMC3772389, 23843611, 23843611, jcs.126102
Format: Citation

Title: 14-3-3 proteins in neurological disorders.
Creator: Foote, Molly, Zhou, Yi
Abstract/Description: 14-3-3 proteins were originally discovered as a family of proteins that are highly expressed in the brain. Through interactions with a multitude of binding partners, 14-3-3 proteins impact many aspects of brain function including neural signaling, neuronal development and neuroprotection. Although much remains to be learned and understood, 14-3-3 proteins have been implicated in a variety of neurological disorders based on evidence from both clinical and laboratory studies. Here we will...
Show more14-3-3 proteins were originally discovered as a family of proteins that are highly expressed in the brain. Through interactions with a multitude of binding partners, 14-3-3 proteins impact many aspects of brain function including neural signaling, neuronal development and neuroprotection. Although much remains to be learned and understood, 14-3-3 proteins have been implicated in a variety of neurological disorders based on evidence from both clinical and laboratory studies. Here we will review previous and more recent research that has helped us understand the roles of 14-3-3 proteins in both neurodegenerative and neuropsychiatric diseases.
Show less
Date Issued: 2012-01-01
Identifier: FSU_pmch_22773956, PMC3388734, 22773956, 22773956
Format: Citation

Title: 14-3-3 proteins are required for hippocampal long-term potentiation and associative learning and memory.
Creator: Qiao, Haifa, Foote, Molly, Graham, Kourtney, Wu, Yuying, Zhou, Yi
Abstract/Description: 14-3-3 is a family of regulatory proteins highly expressed in the brain. Previous invertebrate studies have demonstrated the importance of 14-3-3 in the regulation of synaptic functions and learning and memory. However, the in vivo role of 14-3-3 in these processes has not been determined using mammalian animal models. Here, we report the behavioral and electrophysiological characterization of a new animal model of 14-3-3 proteins. These transgenic mice, considered to be a 14-3-3 functional...
Show more14-3-3 is a family of regulatory proteins highly expressed in the brain. Previous invertebrate studies have demonstrated the importance of 14-3-3 in the regulation of synaptic functions and learning and memory. However, the in vivo role of 14-3-3 in these processes has not been determined using mammalian animal models. Here, we report the behavioral and electrophysiological characterization of a new animal model of 14-3-3 proteins. These transgenic mice, considered to be a 14-3-3 functional knock-out, express a known 14-3-3 inhibitor in various brain regions of different founder lines. We identify a founder-specific impairment in hippocampal-dependent learning and memory tasks, as well as a correlated suppression in long-term synaptic plasticity of the hippocampal synapses. Moreover, hippocampal synaptic NMDA receptor levels are selectively reduced in the transgenic founder line that exhibits both behavioral and synaptic plasticity deficits. Collectively, our findings provide evidence that 14-3-3 is a positive regulator of associative learning and memory at both the behavioral and cellular level.
Show less
Date Issued: 2014-04-02
Identifier: FSU_pmch_24695700, 10.1523/JNEUROSCI.4393-13.2014, PMC3972712, 24695700, 24695700, 34/14/4801
Format: Citation

Title: 14-3-3 and aggresome formation: implications in neurodegenerative diseases..
Creator: Jia, Baohui, Wu, Yuying, Zhou, Yi
Abstract/Description: Protein misfolding and aggregation underlie the pathogenesis of many neurodegenerative diseases. In addition to chaperone-mediated refolding and proteasomal degradation, the aggresome-macroautophagy pathway has emerged as another defense mechanism for sequestration and clearance of toxic protein aggregates in cells. Previously, the 14-3-3 proteins were shown to be indispensable for the formation of aggresomes induced by mutant huntingtin proteins. In a recent study, we have determined that 14...
Show moreProtein misfolding and aggregation underlie the pathogenesis of many neurodegenerative diseases. In addition to chaperone-mediated refolding and proteasomal degradation, the aggresome-macroautophagy pathway has emerged as another defense mechanism for sequestration and clearance of toxic protein aggregates in cells. Previously, the 14-3-3 proteins were shown to be indispensable for the formation of aggresomes induced by mutant huntingtin proteins. In a recent study, we have determined that 14-3-3 functions as a molecular adaptor to recruit chaperone-associated misfolded proteins to dynein motors for transport to aggresomes. This molecular complex involves a dimeric binding of 14-3-3 to both the dynein-intermediate chain (DIC) and an Hsp70 co-chaperone Bcl-2-associated athanogene 3 (BAG3). As 14-3-3 has been implicated in various neurodegenerative diseases, our findings may provide mechanistic insights into its role in managing misfolded protein stress during the process of neurodegeneration.
Show less
Date Issued: 2014-03-01
Identifier: FSU_pmch_24549097, PMC4189886, 24549097, 24549097, 28123
Format: Citation

Title: Amide Hydrogens Reveal A Temperature-dependent Structural Transition That Enhances Site-ii Ca2+ -binding Affinity In A C-domain Mutant Of Cardiac Troponin C.
Creator: Veltri, Tiago, de Oliveira, Guilherme A. P., Bienkiewicz, Ewa A., Palhano, Fernando L., Marques, Mayra de A., Moraes, Adolfo H., Silva, Jerson L., Sorenson, Martha M., Pinto,...
Show moreVeltri, Tiago, de Oliveira, Guilherme A. P., Bienkiewicz, Ewa A., Palhano, Fernando L., Marques, Mayra de A., Moraes, Adolfo H., Silva, Jerson L., Sorenson, Martha M., Pinto, Jose R.
Show less
Abstract/Description: The hypertrophic cardiomyopathy-associated mutant D145E, in cardiac troponin C (cTnC) C-domain, causes generalised instability at multiple sites in the isolated protein. As a result, structure and function of the mutant are more susceptible to higher temperatures. Above 25 degrees C there are large, progressive increases in N-domain Ca2+-binding affinity for D145E but only small changes for the wild-type protein. NMR-derived backbone amide temperature coefficients for many residues show a...
Show moreThe hypertrophic cardiomyopathy-associated mutant D145E, in cardiac troponin C (cTnC) C-domain, causes generalised instability at multiple sites in the isolated protein. As a result, structure and function of the mutant are more susceptible to higher temperatures. Above 25 degrees C there are large, progressive increases in N-domain Ca2+-binding affinity for D145E but only small changes for the wild-type protein. NMR-derived backbone amide temperature coefficients for many residues show a sharp transition above 30-40 degrees C, indicating a temperature-dependent conformational change that is most prominent around the mutated EF-hand IV, as well as throughout the C-domain. Smaller, isolated changes occur in the N-domain. Cardiac skinned fibres reconstituted with D145E are more sensitive to Ca2+ than fibres reconstituted with wild-type, and this defect is amplified near body-temperature. We speculate that the D145E mutation destabilises the native conformation of EF-hand IV, leading to a transient unfolding and dissociation of helix H that becomes more prominent at higher temperatures. This creates exposed hydrophobic surfaces that may be capable of binding unnaturally to a variety of targets, possibly including the N-domain of cTnC when it is in its open Ca2+-saturated state. This would constitute a potential route for propagating signals from one end of TnC to the other.
Show less
Date Issued: 2017-04-06
Identifier: FSU_libsubv1_wos_000398545900010, 10.1038/s41598-017-00777-6
Format: Citation

Title: Amide hydrogens reveal a temperature-dependent structural transition that enhances site-II Ca(2+)-binding affinity in a C-domain mutant of cardiac troponin C.
Creator: Veltri, Tiago, de Oliveira, Guilherme A P, Bienkiewicz, Ewa A, Palhano, Fernando L, Marques, Mayra de A, Moraes, Adolfo H, Silva, Jerson L, Sorenson, Martha M, Pinto, Jose R
Abstract/Description: The hypertrophic cardiomyopathy-associated mutant D145E, in cardiac troponin C (cTnC) C-domain, causes generalised instability at multiple sites in the isolated protein. As a result, structure and function of the mutant are more susceptible to higher temperatures. Above 25 °C there are large, progressive increases in N-domain Ca(2+)-binding affinity for D145E but only small changes for the wild-type protein. NMR-derived backbone amide temperature coefficients for many residues show a sharp...
Show moreThe hypertrophic cardiomyopathy-associated mutant D145E, in cardiac troponin C (cTnC) C-domain, causes generalised instability at multiple sites in the isolated protein. As a result, structure and function of the mutant are more susceptible to higher temperatures. Above 25 °C there are large, progressive increases in N-domain Ca(2+)-binding affinity for D145E but only small changes for the wild-type protein. NMR-derived backbone amide temperature coefficients for many residues show a sharp transition above 30-40 °C, indicating a temperature-dependent conformational change that is most prominent around the mutated EF-hand IV, as well as throughout the C-domain. Smaller, isolated changes occur in the N-domain. Cardiac skinned fibres reconstituted with D145E are more sensitive to Ca(2+) than fibres reconstituted with wild-type, and this defect is amplified near body-temperature. We speculate that the D145E mutation destabilises the native conformation of EF-hand IV, leading to a transient unfolding and dissociation of helix H that becomes more prominent at higher temperatures. This creates exposed hydrophobic surfaces that may be capable of binding unnaturally to a variety of targets, possibly including the N-domain of cTnC when it is in its open Ca(2+)-saturated state. This would constitute a potential route for propagating signals from one end of TnC to the other.
Show less
Date Issued: 2017-04-06
Identifier: FSU_pmch_28386062, 10.1038/s41598-017-00777-6, PMC5429600, 28386062, 28386062, 10.1038/s41598-017-00777-6
Format: Citation

Title: Alternative Folding Nuclei Definitions Facilitate the Evolution of a Symmetric Protein Fold from a Smaller Peptide Motif.
Creator: Longo, Liam, Lee, Jihun, Tenorio, Connie, Blaber, Michael
Abstract/Description: Protein 3° structure symmetry is a defining feature of nearly a third of protein folds and is generally thought to result from a combination of gene duplication, fusion, and truncation events. Such events represent major replication errors, involving substantial alteration of protein 3° structure as well as causing regions of exact repeating 1° structure, both of which are generally considered deleterious to protein folding. Thus, the prevalence of symmetric protein folds is counterintuitive...
Show moreProtein 3° structure symmetry is a defining feature of nearly a third of protein folds and is generally thought to result from a combination of gene duplication, fusion, and truncation events. Such events represent major replication errors, involving substantial alteration of protein 3° structure as well as causing regions of exact repeating 1° structure, both of which are generally considered deleterious to protein folding. Thus, the prevalence of symmetric protein folds is counterintuitive and suggests a specific, yet unexplained, robustness. Using a designed β-trefoil protein, we show that purely symmetric 1° structure enables utilization of alternative definitions of the critical folding nucleus in response to gross structural rearrangement. Thus, major replication errors producing 1° structure symmetry can conserve foldability. The results provide an explanation for the prevalence of symmetric protein folds, and highlight a critical role for 1° structure symmetry in protein evolution.
Show less
Date Issued: 2013-10-17
Identifier: FSU_libsubv1_scholarship_submission_1456501539, 10.1016/j.str.2013.09.003
Format: Citation

Title: Acupoint Sensitization, Acupuncture Analgesia, Acupuncture on Visceral Functional Disorders, and Its Mechanism.
Creator: Yu, Xiaochun, Zhu, Bing, Lin, Zhixiu, Qiao, Haifa, Kong, Jian, Gao, Xinyan
Date Issued: 2015-01-01
Identifier: FSU_pmch_26300944, 10.1155/2015/171759, PMC4537726, 26300944, 26300944
Format: Citation

Title: Acute BDNF treatment upregulates GluR1-SAP97 and GluR2-GRIP1 interactions: implications for sustained AMPA receptor expression..
Creator: Jourdi, Hussam, Kabbaj, Mohamed
Abstract/Description: Brain-derived neurotrophic factor (BDNF) plays several prominent roles in synaptic plasticity and in learning and memory formation. Reduced BDNF levels and altered BDNF signaling have been reported in several brain diseases and behavioral disorders, which also exhibit reduced levels of AMPAr subunits. BDNF treatment acutely regulates AMPA receptor expression and function, including synaptic AMPAr subunit trafficking, and implicates several well defined signaling molecules that are required to...
Show moreBrain-derived neurotrophic factor (BDNF) plays several prominent roles in synaptic plasticity and in learning and memory formation. Reduced BDNF levels and altered BDNF signaling have been reported in several brain diseases and behavioral disorders, which also exhibit reduced levels of AMPAr subunits. BDNF treatment acutely regulates AMPA receptor expression and function, including synaptic AMPAr subunit trafficking, and implicates several well defined signaling molecules that are required to elicit long term potentiation and depression (LTP and LTD, respectively). Long term encoding of synaptic events, as in long term memory formation, requires AMPAr stabilization and maintenance. However, factors regulating AMPAr stabilization in neuronal cell membranes and synaptic sites are not well characterized. In this study, we examine the effects of acute BDNF treatment on levels of AMPAr-associated scaffolding proteins and on AMPAr subunit-scaffolding protein interactions. We also examine the effects of BDNF-dependent enhanced interactions between AMPAr subunits with their specific scaffolding proteins on the accumulation of both types of proteins. Our results show that acute BDNF treatment upregulates the interactions between AMPAr subunits (GluR1 and GluR2) with their scaffold proteins SAP97 and GRIP1, respectively, leading to prolonged increased accumulation of both categories of proteins, albeit with distinct mechanisms for GluR1 and GluR2. Our findings reveal a new role for BDNF in the long term maintenance of AMPA receptor subunits and associated scaffolding proteins at synapses and further support the role of BDNF as a key regulator of synaptic consolidation. These results have potential implications for recent findings implicating BDNF and AMPAr subunits in various brain diseases and behavioral disorders.
Show less
Date Issued: 2013-01-01
Identifier: FSU_pmch_23460828, 10.1371/journal.pone.0057124, PMC3584105, 23460828, 23460828, PONE-D-12-38051
Format: Citation

Title: Activation Profiles of Human Kallikrein-Related Peptidases by Proteases of the Thrombostasis Axis.
Creator: Yoon, Hyesook, Blaber, Sachiko, Evans, D., Trim, Julie, Juliano, Maria, Scarisbrick, Isobel, Blaber, Michael
Abstract/Description: The human kallikrein-related peptidases (KLKs) comprise 15 members (KLK1-15) and are the single largest family of serine proteases. The KLKs are utilized, or proposed, as clinically important biomarkers and therapeutic targets of interest in cancer and neurodegenerative disease. All KLKs appear to be secreted as inactive pro-forms (pro-KLKs) that are activated extracellularly by specific proteolytic release of their N-terminal pro-peptide. This processing is a key step in the regulation of...
Show moreThe human kallikrein-related peptidases (KLKs) comprise 15 members (KLK1-15) and are the single largest family of serine proteases. The KLKs are utilized, or proposed, as clinically important biomarkers and therapeutic targets of interest in cancer and neurodegenerative disease. All KLKs appear to be secreted as inactive pro-forms (pro-KLKs) that are activated extracellularly by specific proteolytic release of their N-terminal pro-peptide. This processing is a key step in the regulation of KLK function. Much recent work has been devoted to elucidating the potential for activation cascades between members of the KLK family, with physiologically relevant KLK regulatory cascades now described in skin desquamation and semen liquefaction. Despite this expanding knowledge of KLK regulation, details regarding the potential for functional intersection of KLKs with other regulatory proteases are essentially unknown. To elucidate such interaction potential, we have characterized the ability of proteases associated with thrombostasis to hydrolyze the pro-peptide sequences of the KLK family using a previously described pro-KLK fusion protein system. A subset of positive hydrolysis results were subsequently quantified with proteolytic assays using intact recombinant pro-KLK proteins. Pro-KLK6 and 14 can be activated by both plasmin and uPA, with plasmin being the best activator of pro-KLK6 identified to date. Pro-KLK11 and 12 can be activated by a broad-spectrum of thrombostasis proteases, with thrombin exhibiting a high degree of selectivity for pro-KLK12. The results show that proteases of the thrombostasis family can efficiently activate specific pro-KLKs, demonstrating the potential for important regulatory interactions between these two major protease families.
Show less
Date Issued: 2008
Identifier: FSU_migr_biomed_faculty_publications-0009
Format: Citation

Title: An S116R Phosphorylation Site Mutation in Human Fibroblast Growth Factor-1 Differentially Affects Mitogenic and Glucose-Lowering Activities.
Creator: Xia, Xue, Kumru, Ozan S, Blaber, Sachiko I, Middaugh, C Russell, Li, Ling, Ornitz, David M, Suh, Jae Myoung, Atkins, Annette R, Downes, Michael, Evans, Ronald M, Tenorio, Connie...
Show moreXia, Xue, Kumru, Ozan S, Blaber, Sachiko I, Middaugh, C Russell, Li, Ling, Ornitz, David M, Suh, Jae Myoung, Atkins, Annette R, Downes, Michael, Evans, Ronald M, Tenorio, Connie A, Bienkiewicz, Ewa, Blaber, Michael
Show less
Abstract/Description: Fibroblast growth factor-1 (FGF-1), a potent human mitogen and insulin sensitizer, signals through both tyrosine kinase receptor-mediated autocrine/paracrine pathways as well as a nuclear intracrine pathway. Phosphorylation of FGF-1 at serine 116 (S116) has been proposed to regulate intracrine signaling. Position S116 is located within a ∼17 amino acid C-terminal loop that contains a rich set of functional determinants including heparin∖heparan sulfate affinity, thiol reactivity, nuclear...
Show moreFibroblast growth factor-1 (FGF-1), a potent human mitogen and insulin sensitizer, signals through both tyrosine kinase receptor-mediated autocrine/paracrine pathways as well as a nuclear intracrine pathway. Phosphorylation of FGF-1 at serine 116 (S116) has been proposed to regulate intracrine signaling. Position S116 is located within a ∼17 amino acid C-terminal loop that contains a rich set of functional determinants including heparin∖heparan sulfate affinity, thiol reactivity, nuclear localization, pharmacokinetics, functional half-life, nuclear ligand affinity, stability, and structural dynamics. Mutational targeting of specific functionality in this region without perturbing other functional determinants is a design challenge. S116R is a non-phosphorylatable variant present in bovine FGF-1 and other members of the human FGF family. We show that the S116R mutation in human FGF-1 is accommodated with no perturbation of biophysical or structural properties, and is therefore an attractive mutation with which to elucidate the functional role of phosphorylation. Characterization of S116R shows reduction in NIH 3T3 fibroblast mitogenic stimulation, increase in fibroblast growth factor receptor-1c activation, and prolonged duration of glucose lowering in ob/ob hyperglycemic mice. A novel FGF-1/fibroblast growth factor receptor-1c dimerization interaction combined with non-phosphorylatable intracrine signaling is hypothesized to be responsible for these observed functional effects.
Show less
Date Issued: 2016-12-01
Identifier: FSU_pmch_27773526, 10.1016/j.xphs.2016.09.005, PMC5310217, 27773526, 27773526, S0022-3549(16)41698-9
Format: Citation

Title: Analysis of the Molecular Pathogenesis of Cardiomyopathy-Causing cTnT Mutants I79N, ΔE96, and ΔK210.
Creator: Bai, Fan, Caster, Hannah, Pinto, Jose, Kawai, Masataka
Abstract/Description: Three troponin T (TnT) mutants that cause hypertrophic, restrictive, and dilated cardiomyopathy (I79N, ΔE96, and ΔK210, respectively), were examined using the thin-filament extraction/reconstitution technique. Effects of Ca(2+), ATP, phosphate, and ADP concentrations on force and its transients were studied at 25°C. Maximal Ca(2+) tension (THC) and Ca(2+)-activatable tension (Tact), respectively, were similar among I79N, ΔE96, and WT, whereas ΔK210 led to a significantly lower THC (∼20% less)...
Show moreThree troponin T (TnT) mutants that cause hypertrophic, restrictive, and dilated cardiomyopathy (I79N, ΔE96, and ΔK210, respectively), were examined using the thin-filament extraction/reconstitution technique. Effects of Ca(2+), ATP, phosphate, and ADP concentrations on force and its transients were studied at 25°C. Maximal Ca(2+) tension (THC) and Ca(2+)-activatable tension (Tact), respectively, were similar among I79N, ΔE96, and WT, whereas ΔK210 led to a significantly lower THC (∼20% less) and Tact (∼25% less) than did WT. In pCa solution containing 8 mM Pi and ionic strength adjusted to 200 mM, the Ca(2+) sensitivity (pCa50) of I79N (5.63 ± 0.02) and ΔE96 (5.60 ± 0.03) was significantly greater than that of WT (5.45 ± 0.04), but the pCa50 of ΔK210 (5.54 ± 0.04) remained similar to that of WT. Five equilibrium constants were deduced using sinusoidal analysis. All three mutants showed significantly lower K0 (ADP association constant) and larger K4 (equilibrium constant of force generation step) relative to the corresponding values for WT. I79N and ΔK210 were associated with a K2 (equilibrium constant of cross-bridge detachment step) significantly lower than that of ΔE96 and WT. These results demonstrated that at pCa 4.66, the force/cross-bridge is ∼18% less in I79N and ∼41% less in ΔK210 than that in WT. These results indicate that the molecular pathogenesis of the cardiac TnT mutation-related cardiomyopathies is different for each mutation.
Show less
Date Issued: 2013
Identifier: FSU_migr_biomed_faculty_publications-0051, 10.1016/j.bpj.2013.04.001
Format: Citation

Title: Accelerated healing in NONcNZO10/LtJ type 2 diabetic mice by FGF 1.
Creator: Blaber, Sachiko, Diaz, Jose, Blaber, Michael
Abstract/Description: The development of novel therapies to treat chronic diabetic ulcers depends upon appropriate animal models for early stage investigation. The NONcNZO10/LtJ mouse is a new polygenic strain developed to more realistically model human metabolic syndrome and obesity-induced Type 2 diabetes; however, detailed wound healing properties have not been reported. In this report we describe a quantitative wound healing study in the NONcNZO10/LtJ mouse using a splinted excisional wound. The rate of wound...
Show moreThe development of novel therapies to treat chronic diabetic ulcers depends upon appropriate animal models for early stage investigation. The NONcNZO10/LtJ mouse is a new polygenic strain developed to more realistically model human metabolic syndrome and obesity-induced Type 2 diabetes; however, detailed wound healing properties have not been reported. In this report we describe a quantitative wound healing study in the NONcNZO10/LtJ mouse using a splinted excisional wound. The rate of wound healing is compared to various controls, and is also quantified in response to topical administration of normal and mutant fibroblast growth factor-1 (FGF-1). Quantitation of re-epithelialization shows that the diabetic condition in the NONcNZO10/LtJ mouse is concomitant with a decreased rate of dermal healing. Furthermore, topical administration of a FGF-1/heparin formulation effectively accelerates re-epithelialization. A similar acceleration can also be achieved by a stabilized mutant form of FGF-1 formulated in the absence of heparin. Such accelerated rates of healing are not associated with any abnormal histology in the healed wounds. The results identify the NONcNZO10/LtJ mouse as a useful model of impaired wound healing in type II diabetes, and further, identify engineered forms of FGF-1 as a potential “second-generation” therapeutic to promote diabetic dermal wound healing.
Show less
Date Issued: 2015-06-19
Identifier: FSU_libsubv1_scholarship_submission_1456505007, 10.1111/wrr.12305
Format: Citation

Title: Akt mediated phosphorylation of LARP6; critical step in biosynthesis of type I collagen.
Creator: Zhang, Yujie, Stefanovic, Branko
Abstract/Description: La ribonucleoprotein domain family, member 6 (LARP6) is the RNA binding protein, which regulates translation of collagen mRNAs and synthesis of type I collagen. Posttranslational modifications of LARP6 and how they affect type I collagen synthesis have not been studied. We show that in lung fibroblasts LARP6 is phosphorylated at 8 serines, 6 of which are located within C-terminal domain. Phosphorylation of LARP6 follows a hierarchical order; S451 phosphorylation being a prerequisite for...
Show moreLa ribonucleoprotein domain family, member 6 (LARP6) is the RNA binding protein, which regulates translation of collagen mRNAs and synthesis of type I collagen. Posttranslational modifications of LARP6 and how they affect type I collagen synthesis have not been studied. We show that in lung fibroblasts LARP6 is phosphorylated at 8 serines, 6 of which are located within C-terminal domain. Phosphorylation of LARP6 follows a hierarchical order; S451 phosphorylation being a prerequisite for phosphorylations of other serines. Inhibition of PI3K/Akt pathway reduced the phosphorylation of LARP6, but had no effect on the S451A mutant, suggesting that PI3K/Akt pathway targets S451 and we have identified Akt as the responsible kinase. Overexpression of S451A mutant had dominant negative effect on collagen biosynthesis; drastically reduced secretion of collagen and induced hyper-modifications of collagen α2 (I) polypeptides. This indicates that LARP6 phosphorylation at S451 is critical for regulating translation and folding of collagen polypeptides. Akt inhibitor, GSK-2141795, which is in clinical trials for treatment of solid tumors, reduced collagen production by human lung fibroblasts with EC50 of 150 nM. This effect can be explained by inhibition of LARP6 phosphorylation and suggests that Akt inhibitors may be effective in treatment of various forms of fibrosis.
Show less
Date Issued: 2016-03-02
Identifier: FSU_pmch_26932461, 10.1038/srep22597, PMC4773855, 26932461, 26932461, srep22597
Format: Citation

Title: Akt mediated phosphorylation of LARP6; critical step in biosynthesis of type I collagen.
Creator: Zhang, Yujie, Stefanovic, Branko
Abstract/Description: La ribonucleoprotein domain family, member 6 (LARP6) is the RNA binding protein, which regulates translation of collagen mRNAs and synthesis of type I collagen. Posttranslational modifications of LARP6 and how they affect type I collagen synthesis have not been studied. We show that in lung fibroblasts LARP6 is phosphorylated at 8 serines, 6 of which are located within C-terminal domain. Phosphorylation of LARP6 follows a hierarchical order; S451 phosphorylation being a prerequisite for...
Show moreLa ribonucleoprotein domain family, member 6 (LARP6) is the RNA binding protein, which regulates translation of collagen mRNAs and synthesis of type I collagen. Posttranslational modifications of LARP6 and how they affect type I collagen synthesis have not been studied. We show that in lung fibroblasts LARP6 is phosphorylated at 8 serines, 6 of which are located within C-terminal domain. Phosphorylation of LARP6 follows a hierarchical order; S451 phosphorylation being a prerequisite for phosphorylations of other serines. Inhibition of PI3K/Akt pathway reduced the phosphorylation of LARP6, but had no effect on the S451A mutant, suggesting that PI3K/Akt pathway targets S451 and we have identified Akt as the responsible kinase. Overexpression of S451A mutant had dominant negative effect on collagen biosynthesis; drastically reduced secretion of collagen and induced hyper-modifications of collagen alpha 2 (I) polypeptides. This indicates that LARP6 phosphorylation at S451 is critical for regulating translation and folding of collagen polypeptides. Akt inhibitor, GSK-2141795, which is in clinical trials for treatment of solid tumors, reduced collagen production by human lung fibroblasts with EC50 of 150 nM. This effect can be explained by inhibition of LARP6 phosphorylation and suggests that Akt inhibitors may be effective in treatment of various forms of fibrosis.
Show less
Date Issued: 2016-03-02
Identifier: FSU_libsubv1_wos_000371176000001, 10.1038/srep22597
Format: Citation

Title: Absence of Myocardial Thyroid Hormone Inactivating Deiodinase Results in Restrictive Cardiomyopathy in Mice.
Creator: Ueta, Cintia, Oskouei, Behzad, Olivares, Emerson, Pinto, Jose, Correa, Mayrin, Simovic, Gordana, Simonides, Warner, Hare, Joshua, Bianco, Antônio Carlos
Abstract/Description: Cardiac injury induces myocardial expression of the thyroid hormone inactivating type 3 deiodinase (D3), which in turn dampens local thyroid hormone signaling. Here, we show that the D3 gene (Dio3) is a tissue-specific imprinted gene in the heart, and thus, heterozygous D3 knockout (HtzD3KO) mice constitute a model of cardiac D3 inactivation in an otherwise systemically euthyroid animal. HtzD3KO newborns have normal hearts but later develop restrictive cardiomyopathy due to cardiac-specific...
Show moreCardiac injury induces myocardial expression of the thyroid hormone inactivating type 3 deiodinase (D3), which in turn dampens local thyroid hormone signaling. Here, we show that the D3 gene (Dio3) is a tissue-specific imprinted gene in the heart, and thus, heterozygous D3 knockout (HtzD3KO) mice constitute a model of cardiac D3 inactivation in an otherwise systemically euthyroid animal. HtzD3KO newborns have normal hearts but later develop restrictive cardiomyopathy due to cardiac-specific increase in thyroid hormone signaling, including myocardial fibrosis, impaired myocardial contractility, and diastolic dysfunction. In wild-type littermates, treatment with isoproterenol-induced myocardial D3 activity and an increase in the left ventricular volumes, typical of cardiac remodeling and dilatation. Remarkably, isoproterenol-treated HtzD3KO mice experienced a further decrease in left ventricular volumes with worsening of the diastolic dysfunction and the restrictive cardiomyopathy, resulting in congestive heart failure and increased mortality. These findings reveal crucial roles for Dio3 in heart function and remodeling, which may have pathophysiologic implications for human restrictive cardiomyopathy.
Show less
Date Issued: 2012
Identifier: FSU_migr_biomed_faculty_publications-0052, 10.1210/me.2011-1325
Format: Citation

Title: The Folding Nucleus Structure Persists in Thermally-Aggregated FGF-1.
Creator: Longo, Liam, Gao, Yuan, Tenorio, Connie, Wang, Gan, Paravastu, Anant, Blaber, Michael
Abstract/Description: An efficient protein folding pathway leading to target structure, and the avoidance of aggregation, is essential to protein evolution and de novo design; however, design details to achieve efficient folding and avoid aggregation are poorly understood. We report characterization of the thermally-induced aggregate of fibroblast growth factor-1 (FGF-1), a small globular protein, by solid-state NMR. NMR spectra are consistent with residual structure in the aggregate and provide evidence of a...
Show moreAn efficient protein folding pathway leading to target structure, and the avoidance of aggregation, is essential to protein evolution and de novo design; however, design details to achieve efficient folding and avoid aggregation are poorly understood. We report characterization of the thermally-induced aggregate of fibroblast growth factor-1 (FGF-1), a small globular protein, by solid-state NMR. NMR spectra are consistent with residual structure in the aggregate and provide evidence of a structured region that corresponds to the region of the folding nucleus. NMR data on aggregated FGF-1 also indicate the presence of unstructured regions that exhibit hydration-dependent dynamics and suggest that unstructured regions of aggregated FGF-1 lie outside the folding nucleus. Since it is known that regions outside the folding nucleus fold late in the folding pathway, we postulate that these regions unfold early in the unfolding pathway and that the partially folded state is more prone to intermolecular aggregation. This interpretation is further supported by comparison with a designed protein that shares the same FGF-1 folding nucleus sequence, but has different 1° structure outside the folding nucleus, and does not thermally aggregate. The results suggest that design of an efficient folding nucleus, and the avoidance of aggregation in the folding pathway, are potentially separable design criteria – the latter of which could principally focus upon the physicochemical properties of 1° structure outside the folding nucleus.
Show less
Date Issued: 2017-10-23
Identifier: FSU_libsubv1_scholarship_submission_1509376995_85b5a7ca, 10.1002/pro.3332
Format: Citation

Title: Fluoxetine exposure during adolescence increases preference for cocaine in adulthood.
Creator: Iñiguez, Sergio D, Riggs, Lace M, Nieto, Steven J, Wright, Katherine N, Zamora, Norma N, Cruz, Bryan, Zavala, Arturo R, Robison, Alfred J, Mazei-Robison, Michelle S
Abstract/Description: Currently, there is a high prevalence of antidepressant prescription rates within juvenile populations, yet little is known about the potential long-lasting consequences of such treatments, particularly on subsequent responses to drugs of abuse. To address this issue at the preclinical level, we examined whether adolescent exposure to fluoxetine (FLX), a selective serotonin reuptake inhibitor, results in changes to the sensitivity of the rewarding properties of cocaine in adulthood. Separate...
Show moreCurrently, there is a high prevalence of antidepressant prescription rates within juvenile populations, yet little is known about the potential long-lasting consequences of such treatments, particularly on subsequent responses to drugs of abuse. To address this issue at the preclinical level, we examined whether adolescent exposure to fluoxetine (FLX), a selective serotonin reuptake inhibitor, results in changes to the sensitivity of the rewarding properties of cocaine in adulthood. Separate groups of male c57bl/6 mice were exposed to FLX (0 or 20 mg/kg) for 15 consecutive days either during adolescence (postnatal days [PD] 35-49) or adulthood (PD 65-79). Twenty-one days after FLX treatment, behavioral responsivity to cocaine (0, 2.5, 5, 10, or 20 mg/kg) conditioned place preference was assessed. Our data shows that mice pretreated with FLX during adolescence, but not during adulthood, display an enhanced dose-dependent preference to the environment paired with cocaine (5 or 10 mg/kg) when compared to age-matched saline pretreated controls. Taken together, our findings suggest that adolescent exposure to FLX increases sensitivity to the rewarding properties of cocaine, later in life.
Show less
Date Issued: 2015-10-09
Identifier: FSU_pmch_26449406, 10.1038/srep15009, PMC4598853, 26449406, 26449406, srep15009
Format: Citation

Title: Frequency dependence of power and its implications for contractile function of muscle fibers from the digital flexors of horses.
Creator: Butcher, Michael T, Bertram, John E A, Syme, Douglas A, Hermanson, John W, Chase, P Bryant
Abstract/Description: The digital flexors of horses must produce high force to support the body weight during running, and a need for these muscles to generate power is likely limited during locomotion over level ground. Measurements of power output from horse muscle fibers close to physiological temperatures, and when cyclic strain is imposed, will help to better understand the in vivo performance of the muscles as power absorbers and generators. Skinned fibers from the deep (DDF) and superficial (SDF) digital...
Show moreThe digital flexors of horses must produce high force to support the body weight during running, and a need for these muscles to generate power is likely limited during locomotion over level ground. Measurements of power output from horse muscle fibers close to physiological temperatures, and when cyclic strain is imposed, will help to better understand the in vivo performance of the muscles as power absorbers and generators. Skinned fibers from the deep (DDF) and superficial (SDF) digital flexors, and the soleus (SOL) underwent sinusoidal oscillations in length over a range of frequencies (0.5-16 Hz) and strain amplitudes (0.01-0.06) under maximum activation (pCa 5) at 30°C. Results were analyzed using both workloop and Nyquist plot analyses to determine the ability of the fibers to absorb or generate power and the frequency dependence of those abilities. Power absorption was dominant at most cycling frequencies and strain amplitudes in fibers from all three muscles. However, small amounts of power were generated (0.002-0.05 Wkg(-1)) at 0.01 strain by all three muscles at relatively slow cycling frequencies: DDF (4-7 Hz), SDF (4-5 Hz) and SOL (0.5-1 Hz). Nyquist analysis, reflecting the influence of cross-bridge kinetics on power generation, corroborated these results. The similar capacity for power generation by DDF and SDF versus lower for SOL, and the faster frequency at which this power was realized in DDF and SDF fibers, are largely explained by the fast myosin heavy chain isoform content in each muscle. Contractile function of DDF and SDF as power absorbers and generators, respectively, during locomotion may therefore be more dependent on their fiber architectural arrangement than on the physiological properties of their muscle fibers.
Show less
Date Issued: 2014-10-07
Identifier: FSU_pmch_25293602, 10.14814/phy2.12174, PMC4254099, 25293602, 25293602, 2/10/e12174
Format: Citation

Title: Eukaryotic Replicative Helicase Subunit Interaction with DNA and Its Role in DNA Replication.
Creator: Martinez, Matthew P, Wacker, Amanda L, Bruck, Irina, Kaplan, Daniel L
Abstract/Description: The replicative helicase unwinds parental double-stranded DNA at a replication fork to provide single-stranded DNA templates for the replicative polymerases. In eukaryotes, the replicative helicase is composed of the Cdc45 protein, the heterohexameric ring-shaped Mcm2-7 complex, and the tetrameric GINS complex (CMG). The CMG proteins bind directly to DNA, as demonstrated by experiments with purified proteins. The mechanism and function of these DNA-protein interactions are presently being...
Show moreThe replicative helicase unwinds parental double-stranded DNA at a replication fork to provide single-stranded DNA templates for the replicative polymerases. In eukaryotes, the replicative helicase is composed of the Cdc45 protein, the heterohexameric ring-shaped Mcm2-7 complex, and the tetrameric GINS complex (CMG). The CMG proteins bind directly to DNA, as demonstrated by experiments with purified proteins. The mechanism and function of these DNA-protein interactions are presently being investigated, and a number of important discoveries relating to how the helicase proteins interact with DNA have been reported recently. While some of the protein-DNA interactions directly relate to the unwinding function of the enzyme complex, other protein-DNA interactions may be important for minichromosome maintenance (MCM) loading, origin melting or replication stress. This review describes our current understanding of how the eukaryotic replicative helicase subunits interact with DNA structures in vitro, and proposed models for the in vivo functions of replicative helicase-DNA interactions are also described.
Show less
Date Issued: 2017-04-06
Identifier: FSU_pmch_28383499, 10.3390/genes8040117, PMC5406864, 28383499, 28383499, genes8040117
Format: Citation

Title: Eukaryotic Replicative Helicase Subunit Interaction With Dna And Its Role In Dna Replication.
Creator: Martinez, Matthew P., Wacker, Amanda L., Bruck, Irina, Kaplan, Daniel L.
Abstract/Description: The replicative helicase unwinds parental double-stranded DNA at a replication fork to provide single-stranded DNA templates for the replicative polymerases. In eukaryotes, the replicative helicase is composed of the Cdc45 protein, the heterohexameric ring-shaped Mcm2-7 complex, and the tetrameric GINS complex (CMG). The CMG proteins bind directly to DNA, as demonstrated by experiments with purified proteins. The mechanism and function of these DNA-protein interactions are presently being...
Show moreThe replicative helicase unwinds parental double-stranded DNA at a replication fork to provide single-stranded DNA templates for the replicative polymerases. In eukaryotes, the replicative helicase is composed of the Cdc45 protein, the heterohexameric ring-shaped Mcm2-7 complex, and the tetrameric GINS complex (CMG). The CMG proteins bind directly to DNA, as demonstrated by experiments with purified proteins. The mechanism and function of these DNA-protein interactions are presently being investigated, and a number of important discoveries relating to how the helicase proteins interact with DNA have been reported recently. While some of the protein-DNA interactions directly relate to the unwinding function of the enzyme complex, other protein-DNA interactions may be important for minichromosome maintenance (MCM) loading, origin melting or replication stress. This review describes our current understanding of how the eukaryotic replicative helicase subunits interact with DNA structures in vitro, and proposed models for the in vivo functions of replicative helicase-DNA interactions are also described.
Show less
Date Issued: 2017-04
Identifier: FSU_libsubv1_wos_000404391700012, 10.3390/genes8040117
Format: Citation

Title: Female mice and rats exhibit species-specific metabolic and behavioral responses to ovariectomy.
Creator: Witte, Michelina Messina, Resuehr, David, Chandler, Ashley R, Mehle, Ashlee K, Overton, J Michael
Abstract/Description: Ovariectomy (OVX) leads to hyperphagia and weight gain in rats, which can be prevented by estradiol (E2) replacement; however, the role of endogenous E2 on feeding and energy homeostasis in female mice has not been well characterized. The primary goal of this study was to assess the relative contribution of increased energy intake and decreased energy expenditure to OVX-induced weight gain in female rats and mice. OVX led to hyperphagia in rats, but did not produce daily, nor cumulative,...
Show moreOvariectomy (OVX) leads to hyperphagia and weight gain in rats, which can be prevented by estradiol (E2) replacement; however, the role of endogenous E2 on feeding and energy homeostasis in female mice has not been well characterized. The primary goal of this study was to assess the relative contribution of increased energy intake and decreased energy expenditure to OVX-induced weight gain in female rats and mice. OVX led to hyperphagia in rats, but did not produce daily, nor cumulative, hyperphagia in mice. OVX decreased mass-specific metabolic rate in mice, but not in rats. OVX decreased home cage locomotor activity in both species. Pair-feeding attenuated OVX-induced weight gain in rats and produced both short- and long-term changes in expression of key hypothalamic genes involved in food intake and energy homeostasis, i.e., the anorexigenic neuropeptide pro-opiomelanocortin (POMC) and the orexigenic neuropeptides: melanin-concentrating hormone (MCH) and agouti-related peptide (AgRP). No differences in hypothalamic gene expression were observed between OVX'd and sham mice. The results suggest that OVX-induced weight gain is mediated by hyperphagia and reduced locomotor activity in rats, but that in mice, it is primarily mediated by reduced locomotor activity and metabolic rate.
Show less
Date Issued: 2010-05-01
Identifier: FSU_pmch_20067798, 10.1016/j.ygcen.2010.01.006, PMC2856744, 20067798, 20067798, S0016-6480(10)00009-2
Format: Citation

Title: Global mitotic phosphorylation of C2H2 zinc finger protein linker peptides.
Creator: Rizkallah, Raed, Alexander, Karen E, Hurt, Myra M
Abstract/Description: Cessation of transcriptional activity is a hallmark of cell division. Many biochemical pathways have been shown and proposed over the past few decades to explain the silence of this phase. In particular, many individual transcription factors have been shown to be inactivated by phosphorylation. In this report, we show the simultaneous phosphorylation and mitotic redistribution of a whole class of modified transcription factors. C(2)H(2) zinc finger proteins (ZFPs) represent the largest group...
Show moreCessation of transcriptional activity is a hallmark of cell division. Many biochemical pathways have been shown and proposed over the past few decades to explain the silence of this phase. In particular, many individual transcription factors have been shown to be inactivated by phosphorylation. In this report, we show the simultaneous phosphorylation and mitotic redistribution of a whole class of modified transcription factors. C(2)H(2) zinc finger proteins (ZFPs) represent the largest group of gene expression regulators in the human genome. Despite their diversity, C(2)H(2) ZFPs display striking conservation of small linker peptides joining their adjacent zinc finger modules. These linkers are critical for DNA binding activity. It has been proposed that conserved phosphorylation of these linker peptides could be a common mechanism for the inactivation of the DNA binding activity of C(2)H(2) ZFPs, during mitosis. Using a novel antibody, raised against the phosphorylated form of the most conserved linker peptide sequence, we are able to visualize the massive and simultaneous mitotic phosphorylation of hundreds of these proteins. We show that this wave of phosphorylation is tightly synchronized, starting in mid-prophase right after DNA condensation and before the breakdown of the nuclear envelope. This global phosphorylation is completely reversed in telophase. In addition, the exclusion of the phospho-linker signal from condensed DNA clearly demonstrates a common mechanism for the mitotic inactivation of C(2)H(2) ZFPs.
Show less
Date Issued: 2011-10-01
Identifier: FSU_pmch_21941085, 10.4161/cc.10.19.17619, PMC3233627, 21941085, 21941085, 17619
Format: Citation

Title: Glucagon-like peptide 1 receptor activation regulates cocaine actions and dopamine homeostasis in the lateral septum by decreasing arachidonic acid levels.
Format: Citation

Title: Glucagon-like peptide 1 receptor activation regulates cocaine actions and dopamine homeostasis in the lateral septum by decreasing arachidonic acid levels.
Creator: Reddy, I A, Pino, J A, Weikop, P, Osses, N, Sørensen, G, Bering, T, Valle, C, Bluett, R J, Erreger, K, Wortwein, G, Reyes, J G, Graham, D, Stanwood, G D, Hackett, T A, Patel, S,...
Show moreReddy, I A, Pino, J A, Weikop, P, Osses, N, Sørensen, G, Bering, T, Valle, C, Bluett, R J, Erreger, K, Wortwein, G, Reyes, J G, Graham, D, Stanwood, G D, Hackett, T A, Patel, S, Fink-Jensen, A, Torres, G E, Galli, A
Show less
Abstract/Description: Agonism of the glucagon-like peptide 1 (GLP-1) receptor (GLP-1R) has been effective at treating aspects of addictive behavior for a number of abused substances, including cocaine. However, the molecular mechanisms and brain circuits underlying the therapeutic effects of GLP-1R signaling on cocaine actions remain elusive. Recent evidence has revealed that endogenous signaling at the GLP-1R within the forebrain lateral septum (LS) acts to reduce cocaine-induced locomotion and cocaine...
Show moreAgonism of the glucagon-like peptide 1 (GLP-1) receptor (GLP-1R) has been effective at treating aspects of addictive behavior for a number of abused substances, including cocaine. However, the molecular mechanisms and brain circuits underlying the therapeutic effects of GLP-1R signaling on cocaine actions remain elusive. Recent evidence has revealed that endogenous signaling at the GLP-1R within the forebrain lateral septum (LS) acts to reduce cocaine-induced locomotion and cocaine conditioned place preference, both considered dopamine (DA)-associated behaviors. DA terminals project from the ventral tegmental area to the LS and express the DA transporter (DAT). Cocaine acts by altering DA bioavailability by targeting the DAT. Therefore, GLP-1R signaling might exert effects on DAT to account for its regulation of cocaine-induced behaviors. We show that the GLP-1R is highly expressed within the LS. GLP-1, in LS slices, significantly enhances DAT surface expression and DAT function. Exenatide (Ex-4), a long-lasting synthetic analog of GLP-1 abolished cocaine-induced elevation of DA. Interestingly, acute administration of Ex-4 reduces septal expression of the retrograde messenger 2-arachidonylglycerol (2-AG), as well as a product of its presynaptic degradation, arachidonic acid (AA). Notably, AA reduces septal DAT function pointing to AA as a novel regulator of central DA homeostasis. We further show that AA oxidation product γ-ketoaldehyde (γ-KA) forms adducts with the DAT and reduces DAT plasma membrane expression and function. These results support a mechanism in which postsynaptic septal GLP-1R activation regulates 2-AG levels to alter presynaptic DA homeostasis and cocaine actions through AA.
Show less
Date Issued: 2016-05-17
Identifier: FSU_pmch_27187231, 10.1038/tp.2016.86, PMC5070047, 27187231, 27187231, tp201686
Format: Citation

Title: Evolution and design of protein structure by folding nucleus symmetric expansion.
Creator: Longo, Liam, Kumru, Ozan, Middaugh, Russell, Blaber, Michael
Abstract/Description: Models of symmetric protein evolution typically invoke gene duplication and fusion events, in which repetition of a structural motif generates foldable, stable symmetric protein architecture. Success of such evolutionary processes suggests that the duplicated structural motif must be capable of nucleating protein folding. If correct, symmetric expansion of a folding nucleus sequence derived from an extant symmetric fold may be an elegant and computationally tractable solution to de novo...
Show moreModels of symmetric protein evolution typically invoke gene duplication and fusion events, in which repetition of a structural motif generates foldable, stable symmetric protein architecture. Success of such evolutionary processes suggests that the duplicated structural motif must be capable of nucleating protein folding. If correct, symmetric expansion of a folding nucleus sequence derived from an extant symmetric fold may be an elegant and computationally tractable solution to de novo protein design. We report the efficient de novo design of a β-trefoil protein by symmetric expansion of a β-trefoil folding nucleus, previously identified by ɸ-value analysis. The resulting protein, having exact sequence symmetry, exhibits superior folding properties compared to its naturally evolved progenitor--with the potential for redundant folding nuclei. In principle, folding nucleus symmetric expansion can be applied to any given symmetric protein fold (that is, nearly 1/3 of the known proteome) provided information of the folding nucleus is available.
Show less
Date Issued: 2014-10-07
Identifier: FSU_libsubv1_scholarship_submission_1456503265, 10.1016/j.str.2014.08.008
Format: Citation

Title: Genetic Influences on Pharmacological Interventions in Psoriasis.
Creator: Ahmed, Hana, Yusuf, Nabiha
Abstract/Description: Psoriasis is a common chronic inflammatory disease that affects 2% of the population. Therapeutic intervention for psoriasis mainly targets inflammatory cascade through the use of topical agents, phototherapy, systemic agents and the newer biologic agents. The efficacy of many treatments used in psoriasis varies from patient to patient, and some of this variance in response can presumably be attributed to genetic differences. While current research findings are still limited, the clinical...
Show morePsoriasis is a common chronic inflammatory disease that affects 2% of the population. Therapeutic intervention for psoriasis mainly targets inflammatory cascade through the use of topical agents, phototherapy, systemic agents and the newer biologic agents. The efficacy of many treatments used in psoriasis varies from patient to patient, and some of this variance in response can presumably be attributed to genetic differences. While current research findings are still limited, the clinical utilization of pharmacogenetics allows for tailored treatment plans that have the potential for better response amongst patients as well as conserving expenditures and healthcare resources. In this review, we hope to focus and summarize the conclusions and findings of studies done on the topic of pharmacogenetics in the treatment of psoriasis.
Show less
Date Issued: 2017-04-24
Identifier: FSU_libsubv1_scholarship_submission_1516305863_e8df6723, 10.4172/2155-9554.1000392
Format: Citation

Title: Enhanced troponin I binding explains the functional changes produced by the hypertrophic cardiomyopathy mutation A8V of cardiac troponin C.
Creator: Zot, Henry G, Hasbun, Javier E, Michell, Clara A, Landim-Vieira, Maicon, Pinto, Jose R
Abstract/Description: Higher affinity for TnI explains how troponin C (TnC) carrying a causative hypertrophic cardiomyopathy mutation, TnC(A8V), sensitizes muscle cells to Ca(2+). Muscle fibers reconstituted with TnC(A8V) require ∼2.3-fold less [Ca(2+)] to achieve 50% maximum-tension compared to fibers reconstituted with wild-type TnC (TnC(WT)). Binding measurements rule out a significant change in N-terminus Ca(2+)-affinity of isolated TnC(A8V), and TnC(A8V) binds the switch-peptide of troponin-I (TnI(sp)) ∼1.6...
Show moreHigher affinity for TnI explains how troponin C (TnC) carrying a causative hypertrophic cardiomyopathy mutation, TnC(A8V), sensitizes muscle cells to Ca(2+). Muscle fibers reconstituted with TnC(A8V) require ∼2.3-fold less [Ca(2+)] to achieve 50% maximum-tension compared to fibers reconstituted with wild-type TnC (TnC(WT)). Binding measurements rule out a significant change in N-terminus Ca(2+)-affinity of isolated TnC(A8V), and TnC(A8V) binds the switch-peptide of troponin-I (TnI(sp)) ∼1.6-fold more strongly than TnC(WT); thus we model the TnC-TnI(sp) interaction as competing with the TnI-actin interaction. Tension data are well-fit by a model constrained to conditions in which the affinity of TnC(A8V) for TnI(sp) is 1.5-1.7-fold higher than that of TnC(WT) at all [Ca(2+)]. Mean ATPase rates of reconstituted cardiac myofibrils is greater for TnC(A8V) than TnC(WT) at all [Ca(2+)], with statistically significant differences in the means at higher [Ca(2+)]. To probe TnC-TnI interaction in low Ca(2+), displacement of bis-ANS from TnI was monitored as a function of TnC. Whereas Ca(2+)-TnC(WT) displaces significantly more bis-ANS than Mg(2+)-TnC(WT), Ca(2+)-TnC(A8V) displaces probe equivalently to Mg(2+)-TnC(A8V) and Ca(2+)-TnC(WT), consistent with stronger Ca(2+)-independent TnC(A8V)-TnI(sp). A Matlab program for computing theoretical activation is reported. Our work suggests that contractility is constantly above normal in hearts made hypertrophic by TnC(A8V).
Show less
Date Issued: 2016-07-01
Identifier: FSU_pmch_26976709, 10.1016/j.abb.2016.03.011, PMC4899184, 26976709, 26976709, S0003-9861(16)30063-7
Format: Citation

Title: ExtraPEG: A Polyethylene Glycol-Based Method for Enrichment of Extracellular Vesicles..
Creator: Rider, Mark A, Hurwitz, Stephanie N, Meckes, David G
Abstract/Description: Initially thought to be a means for cells to eliminate waste, secreted extracellular vesicles, known as exosomes, are now understood to mediate numerous healthy and pathological processes. Though abundant in biological fluids, purifying exosomes has been challenging because their biophysical properties overlap with other secreted cell products. Easy-to-use commercial kits for harvesting exosomes are now widely used, but the relative low-purity and high-cost of the preparations restricts their...
Show moreInitially thought to be a means for cells to eliminate waste, secreted extracellular vesicles, known as exosomes, are now understood to mediate numerous healthy and pathological processes. Though abundant in biological fluids, purifying exosomes has been challenging because their biophysical properties overlap with other secreted cell products. Easy-to-use commercial kits for harvesting exosomes are now widely used, but the relative low-purity and high-cost of the preparations restricts their utility. Here we describe a method for purifying exosomes and other extracellular vesicles by adapting methods for isolating viruses using polyethylene glycol. This technique, called ExtraPEG, enriches exosomes from large volumes of media rapidly and inexpensively using low-speed centrifugation, followed by a single small-volume ultracentrifugation purification step. Total protein and RNA harvested from vesicles is sufficient in quantity and quality for proteomics and sequencing analyses, demonstrating the utility of this method for biomarker discovery and diagnostics. Additionally, confocal microscopy studies suggest that the biological activity of vesicles is not impaired. The ExtraPEG method can be easily adapted to enrich for different vesicle populations, or as an efficient precursor to subsequent purification techniques, providing a means to harvest exosomes from many different biological fluids and for a wide variety of purposes.
Show less
Date Issued: 2016-04-12
Identifier: FSU_pmch_27068479, 10.1038/srep23978, PMC4828635, 27068479, 27068479, srep23978
Format: Citation

Title: Extracellular signal-regulated kinase 2 signaling in the hippocampal dentate gyrus mediates the antidepressant effects of testosterone.
Creator: Carrier, Nicole, Kabbaj, Mohamed
Abstract/Description: Human and animal studies suggest that testosterone may have antidepressant effects. In this study, we sought to investigate the molecular mechanisms underlying the antidepressant effects of testosterone within the hippocampus, an area that is fundamental in the etiology of depression. The effects of testosterone replacements in gonadectomized adult male rats were investigated using the sucrose preference and forced swim tests. We explored possible effects of testosterone on hippocampal...
Show moreHuman and animal studies suggest that testosterone may have antidepressant effects. In this study, we sought to investigate the molecular mechanisms underlying the antidepressant effects of testosterone within the hippocampus, an area that is fundamental in the etiology of depression. The effects of testosterone replacements in gonadectomized adult male rats were investigated using the sucrose preference and forced swim tests. We explored possible effects of testosterone on hippocampal neurogenesis and gene expression of stress-related molecules. Through the use of viral vectors, we pursued the antidepressant molecular mechanism(s) of testosterone in mediating anhedonia and manipulated extracellular signal-regulated kinase 2 (ERK2) expression in the dentate gyrus in gonadectomized rats with testosterone replacements. Testosterone had antidepressant effects, likely mediated by aromatization to estrogen metabolites, in the sucrose preference and forced swim tests despite having no effects on hippocampal cell proliferation or survival. We found a testosterone-dependent regulation of hippocampal ERK2 expression. Functionally, reducing ERK2 activity within the dentate gyrus induced anhedonia in gonadectomized rats receiving testosterone supplementation, whereas the overexpression of ERK2 rescued this behavior in gonadectomized rats. These results implicate a role for ERK2 signaling within the dentate gyrus area of the hippocampus as a key mediator of the antidepressant effects of testosterone.
Show less
Date Issued: 2012-04-01
Identifier: FSU_pmch_22265242, 10.1016/j.biopsych.2011.11.028, PMC3307821, 22265242, 22265242, S0006-3223(11)01201-7
Format: Citation

Title: Expression and Function of the Kallikrein-Related Peptidase 6 in the Human Melanoma Microenvironment.
Creator: Krenzer, Stefanie, Peterziel, Heike, Mauch, Cornelia, Blaber, Sachiko, Blaber, Michael, Angel, Peter, Hess, Jochen
Abstract/Description: Cutaneous malignant melanoma is an aggressive disease of poor prognosis. Clinical and experimental studies have provided major insight into the pathogenesis of the disease, including the functional interaction between melanoma cells and surrounding keratinocytes, fibroblasts, and immune cells. Nevertheless, patients with metastasized melanoma have a very poor prognosis and are largely refractory to clinical therapies. Hence, diagnostic tools to monitor melanoma development, as well as...
Show moreCutaneous malignant melanoma is an aggressive disease of poor prognosis. Clinical and experimental studies have provided major insight into the pathogenesis of the disease, including the functional interaction between melanoma cells and surrounding keratinocytes, fibroblasts, and immune cells. Nevertheless, patients with metastasized melanoma have a very poor prognosis and are largely refractory to clinical therapies. Hence, diagnostic tools to monitor melanoma development, as well as therapeutic targets, are urgently needed. We investigated the expression pattern of the kallikrein-related peptidase 6 (KLK6) in human melanoma tissue sections throughout tumor development. Although KLK6 was not detectable in tumor cells, we found strong KLK6 protein expression in keratinocytes and stromal cells located adjacent to benign nevi, primary melanomas, and cutaneous metastatic lesions, suggesting a paracrine function of extracellular KLK6 during neoplastic transformation and malignant progression. Accordingly, recombinant Klk6 protein significantly induced melanoma cell migration and invasion accompanied by an accelerated intracellular Ca(2+) flux. We could further demonstrate that KLK6-induced intracellular Ca(2+) flux and tumor cell invasion critically depends on the protease-activated receptor 1 (PAR1). Our data provide experimental evidence that specific inhibition of the KLK6-PAR1 axis may interfere with the deleterious effect of tumor-microenvironment interaction and represent a potential option for translational melanoma research.
Show less
Date Issued: 2011
Identifier: FSU_migr_biomed_faculty_publications-0024, 10.1038/jid.2011.190
Format: Citation

Title: Gastric cancer associated variant of DNA polymerase beta (Leu22Pro) promotes DNA replication associated double strand breaks.
Creator: Rozacky, Jenna, Nemec, Antoni A, Sweasy, Joann B, Kidane, Dawit
Abstract/Description: DNA polymerase beta (Pol β) is a key enzyme for the protection against oxidative DNA lesions via its role in base excision repair (BER). Approximately 1/3 of tumors studied to date express Pol β variant proteins, and several tumors overexpress Pol β. Pol β possesses DNA polymerase and dRP lyase activities, both of which are known to be important for efficient BER. The dRP lyase activity resides within the 8kDa amino terminal domain of Pol β, is responsible for removal of the 5' phosphate...
Show moreDNA polymerase beta (Pol β) is a key enzyme for the protection against oxidative DNA lesions via its role in base excision repair (BER). Approximately 1/3 of tumors studied to date express Pol β variant proteins, and several tumors overexpress Pol β. Pol β possesses DNA polymerase and dRP lyase activities, both of which are known to be important for efficient BER. The dRP lyase activity resides within the 8kDa amino terminal domain of Pol β, is responsible for removal of the 5' phosphate group (5'-dRP). The DNA polymerase subsequently fills the gaps. Previously, we demonstrated that the human gastric cancer-associated variant of Pol β (Leu22Pro (L22P)) lacks dRP lyase function in vitro. Here, we report that L22P-expressing cells harbor significantly increased replication associated DNA double strand breaks (DSBs) and defective maintenance of the nascent DNA strand (NDS) during replication stress. Moreover, L22P-expressing cells are sensitive to PARP1 inhibitors, which suggests trapped PARP1 binds to the 5'-dRP group and blocks replications forks, resulting in fork collapse and DSBs. Our data suggest that the normal function of the dRP lyase is critical to maintain replication fork integrity and prevent replication fork collapse to DSBs and cellular transformation.
Show less
Date Issued: 2015-09-15
Identifier: FSU_pmch_26090616, 10.18632/oncotarget.4426, PMC4695199, 26090616, 26090616, 4426
Format: Citation

Title: Essential roles of CKIdelta and CKIepsilon in the mammalian circadian clock.
Creator: Lee, Hyeongmin, Chen, Rongmin, Lee, Yongjin, Yoo, Seunghee, Lee, Choogon
Abstract/Description: Circadian rhythms in mammals are generated by a negative transcriptional feedback loop in which PERIOD (PER) is rate-limiting for feedback inhibition. Casein kinases Idelta and Iepsilon (CKIdelta/epsilon) can regulate temporal abundance/activity of PER by phosphorylation-mediated degradation and cellular localization. Despite their potentially crucial effects on PER, it has not been demonstrated in a mammalian system that these kinases play essential roles in circadian rhythm generation as...
Show moreCircadian rhythms in mammals are generated by a negative transcriptional feedback loop in which PERIOD (PER) is rate-limiting for feedback inhibition. Casein kinases Idelta and Iepsilon (CKIdelta/epsilon) can regulate temporal abundance/activity of PER by phosphorylation-mediated degradation and cellular localization. Despite their potentially crucial effects on PER, it has not been demonstrated in a mammalian system that these kinases play essential roles in circadian rhythm generation as does their homolog in Drosophila. To disrupt both CKIdelta/epsilon while avoiding the embryonic lethality of CKIdelta disruption in mice, we used CKIdelta-deficient Per2(Luc) mouse embryonic fibroblasts (MEFs) and overexpressed a dominant-negative mutant CKIepsilon (DN-CKIepsilon) in the mutant MEFs. CKIdelta-deficient MEFs exhibited a robust circadian rhythm, albeit with a longer period, suggesting that the cells possess a way to compensate for CKIdelta loss. When CKIepsilon activity was disrupted by the DN-CKIepsilon in the mutant MEFs, circadian bioluminescence rhythms were eliminated and rhythms in endogenous PER abundance and phosphorylation were severely compromised, demonstrating that CKIdelta/epsilon are indeed essential kinases for the clockwork. This is further supported by abolition of circadian rhythms when physical interaction between PER and CKIdelta/epsilon was disrupted by overexpressing the CKIdelta/epsilon binding domain of PER2 (CKBD-P2). Interestingly, CKBD-P2 overexpression led to dramatically low levels of endogenous PER, while PER-binding, kinase-inactive DN-CKIepsilon did not, suggesting that CKIdelta/epsilon may have a non-catalytic role in stabilizing PER. Our results show that an essential role of CKIdelta/epsilon is conserved between Drosophila and mammals, but CKIdelta/epsilon and DBT may have divergent non-catalytic functions in the clockwork as well.
Show less
Date Issued: 2009-12-15
Identifier: FSU_pmch_19948962, 10.1073/pnas.0906651106, PMC2795500, 19948962, 19948962, 0906651106
Format: Citation

Title: Exercise training reverses aging-induced impairment of myogenic constriction in skeletal muscle arterioles.
Creator: Ghosh, Payal, Mora Solis, Fredy R, Dominguez, James M, Spier, Scott A, Donato, Anthony J, Delp, Michael D, Muller-Delp, Judy M
Abstract/Description: To investigate whether exercise training can reverse age-related impairment of myogenic vasoconstriction in skeletal muscle arterioles, young (4 mo) and old (22 mo) male Fischer 344 rats were randomly assigned to either sedentary or exercise-trained groups. The roles of the endothelium and Kv1 channels in age- and exercise training-induced adaptations of myogenic responses were assessed through evaluation of pressure-induced constriction in endothelium-intact and denuded soleus muscle...
Show moreTo investigate whether exercise training can reverse age-related impairment of myogenic vasoconstriction in skeletal muscle arterioles, young (4 mo) and old (22 mo) male Fischer 344 rats were randomly assigned to either sedentary or exercise-trained groups. The roles of the endothelium and Kv1 channels in age- and exercise training-induced adaptations of myogenic responses were assessed through evaluation of pressure-induced constriction in endothelium-intact and denuded soleus muscle arterioles in the presence and absence of the Kv1 channel blocker, correolide. Exercise training enhanced myogenic constriction in arterioles from both old and young rats. In arterioles from old rats, exercise training restored myogenic constriction to a level similar to that of arterioles from young sedentary rats. Removal of the endothelium did not alter myogenic constriction of arterioles from young sedentary rats, but reduced myogenic constriction in arterioles from young exercise-trained rats. In contrast, endothelial removal had no effect on myogenic constriction of arterioles from old exercise-trained rats, but increased myogenic vasoconstriction in old sedentary rats. The effect of Kv1 channel blockade was also dependent on age and training status. In arterioles from young sedentary rats, Kv1 blockade had little effect on myogenic constriction, whereas in old sedentary rats Kv1 blockade increased myogenic constriction. After exercise training, Kv1 channel blockade increased myogenic constriction in arterioles from both young and old rats. Thus exercise training restores myogenic constriction of arterioles from old rats and enhances myogenic constriction from young rats through adaptations of the endothelium and smooth muscle Kv1 channels.
Show less
Date Issued: 2015-04-01
Identifier: FSU_pmch_25634999, 10.1152/japplphysiol.00277.2014, PMC4422370, 25634999, 25634999, japplphysiol.00277.2014
Format: Citation

Title: Exosomal communication goes viral.
Creator: Meckes, David G
Abstract/Description: Exosomes are small vesicles secreted from cells that participate in intercellular communication events. Accumulating evidence demonstrates that host exosome pathways are hijacked by viruses and that virally modified exosomes contribute to virus spread and immune evasion. In the case of tumor viruses, recent findings suggest that alterations in normal exosome biology may promote the development and progression of cancer. These studies will be discussed in the context of our current knowledge...
Show moreExosomes are small vesicles secreted from cells that participate in intercellular communication events. Accumulating evidence demonstrates that host exosome pathways are hijacked by viruses and that virally modified exosomes contribute to virus spread and immune evasion. In the case of tumor viruses, recent findings suggest that alterations in normal exosome biology may promote the development and progression of cancer. These studies will be discussed in the context of our current knowledge of Epstein-Barr virus (EBV)-modified exosomes.
Show less
Date Issued: 2015-05-01
Identifier: FSU_pmch_25740980, 10.1128/JVI.02470-14, PMC4442506, 25740980, 25740980, JVI.02470-14
Format: Citation

Title: Excess histone levels mediate cytotoxicity via multiple mechanisms.
Creator: Singh, Rakesh Kumar, Liang, Dun, Gajjalaiahvari, Ugander Reddy, Kabbaj, Marie-Helene Miquel, Paik, Johanna, Gunjan, Akash
Abstract/Description: The accumulation of excess histone proteins in cells has deleterious consequences such as genomic instability in the form of excessive chromosome loss, enhanced sensitivity to DNA damaging agents and cytotoxicity. Hence, the synthesis of histone proteins is tightly regulated at multiple steps and transcriptional as well as posttranscriptional regulation of histone proteins is well established. Additionally, we have recently demonstrated that histone protein levels are regulated...
Show moreThe accumulation of excess histone proteins in cells has deleterious consequences such as genomic instability in the form of excessive chromosome loss, enhanced sensitivity to DNA damaging agents and cytotoxicity. Hence, the synthesis of histone proteins is tightly regulated at multiple steps and transcriptional as well as posttranscriptional regulation of histone proteins is well established. Additionally, we have recently demonstrated that histone protein levels are regulated posttranslationally by the DNA damage checkpoint kinase Rad53 and ubiquitin-proteasome dependent proteolysis in the budding yeast. However, the underlying mechanism/s via which excess histones exert their deleterious effects in vivo are not clear. Here we have investigated the mechanistic basis for the deleterious effects of excess histones in budding yeast. We find that the presence of excess histones saturates certain histone modifying enzymes, potentially interfering with their activities. Additionally, excess histones appear to bind non-specifically to DNA as well as RNA, which can adversely affect their metabolism. Microarray analysis revealed that upon overexpression of histone gene pairs, about 240 genes were either up or downregulated by 2-fold or more. Overall, we present evidence that excess histones are likely to mediate their cytotoxic effects via multiple mechanisms that are primarily dependent on inappropriate electrostatic interactions between the positively charged histones and diverse negatively charged molecules in the cell. Our findings help explain the basis for the existence of multiple distinct mechanisms that contribute to the tight control of histone protein levels in cells and highlight their importance in maintaining genomic stability and cell viability.
Show less
Date Issued: 2010-10-15
Identifier: FSU_pmch_20948314, 10.4161/cc.9.20.13636, PMC3055206, 20948314, 20948314, 13636
Format: Citation

Title: Fin1-PP1 Helps Clear Spindle Assembly Checkpoint Protein Bub1 from Kinetochores in Anaphase.
Creator: Bokros, Michael, Gravenmier, Curtis, Jin, Fengzhi, Richmond, Daniel, Wang, Yanchang
Abstract/Description: The spindle assembly checkpoint (SAC) monitors chromosome attachment defects, and the assembly of SAC proteins at kinetochores is essential for its activation, but the SAC disassembly process remains unknown. We found that deletion of a 14-3-3 protein, Bmh1, or hyperactivation of Cdc14 early anaphase release (FEAR) allows premature SAC silencing in budding yeast, which depends on a kinetochore protein Fin1 that forms a complex with protein phosphatase PP1. Previous works suggest that FEAR...
Show moreThe spindle assembly checkpoint (SAC) monitors chromosome attachment defects, and the assembly of SAC proteins at kinetochores is essential for its activation, but the SAC disassembly process remains unknown. We found that deletion of a 14-3-3 protein, Bmh1, or hyperactivation of Cdc14 early anaphase release (FEAR) allows premature SAC silencing in budding yeast, which depends on a kinetochore protein Fin1 that forms a complex with protein phosphatase PP1. Previous works suggest that FEAR-dependent Fin1 dephosphorylation promotes Bmh1-Fin1 dissociation, which enables kinetochore recruitment of Fin1-PP1. We found persistent kinetochore association of SAC protein Bub1 in fin1 Delta mutants after anaphase entry. Therefore, we revealed a mechanism that clears SAC proteins from kinetochores. After anaphase entry, FEAR activation promotes kinetochore enrichment of Fin1-PP1, resulting in SAC disassembly at kinetochores. This mechanism is required for efficient SAC silencing after SAC is challenged, and untimely Fin1-kinetochore association causes premature SAC silencing and chromosome missegregation.
Show less
Date Issued: 2016-02-09
Identifier: FSU_libsubv1_wos_000369616100011, 10.1016/j.celrep.2016.01.007
Format: Citation

Title: Fin1-PP1 Helps Clear Spindle Assembly Checkpoint Protein Bub1 from Kinetochores in Anaphase.
Creator: Bokros, Michael, Gravenmier, Curtis, Jin, Fengzhi, Richmond, Daniel, Wang, Yanchang
Abstract/Description: The spindle assembly checkpoint (SAC) monitors chromosome attachment defects, and the assembly of SAC proteins at kinetochores is essential for its activation, but the SAC disassembly process remains unknown. We found that deletion of a 14-3-3 protein, Bmh1, or hyperactivation of Cdc14 early anaphase release (FEAR) allows premature SAC silencing in budding yeast, which depends on a kinetochore protein Fin1 that forms a complex with protein phosphatase PP1. Previous works suggest that FEAR...
Show moreThe spindle assembly checkpoint (SAC) monitors chromosome attachment defects, and the assembly of SAC proteins at kinetochores is essential for its activation, but the SAC disassembly process remains unknown. We found that deletion of a 14-3-3 protein, Bmh1, or hyperactivation of Cdc14 early anaphase release (FEAR) allows premature SAC silencing in budding yeast, which depends on a kinetochore protein Fin1 that forms a complex with protein phosphatase PP1. Previous works suggest that FEAR-dependent Fin1 dephosphorylation promotes Bmh1-Fin1 dissociation, which enables kinetochore recruitment of Fin1-PP1. We found persistent kinetochore association of SAC protein Bub1 in fin1Δ mutants after anaphase entry. Therefore, we revealed a mechanism that clears SAC proteins from kinetochores. After anaphase entry, FEAR activation promotes kinetochore enrichment of Fin1-PP1, resulting in SAC disassembly at kinetochores. This mechanism is required for efficient SAC silencing after SAC is challenged, and untimely Fin1-kinetochore association causes premature SAC silencing and chromosome missegregation.
Show less
Date Issued: 2016-02-09
Identifier: FSU_pmch_26832405, 10.1016/j.celrep.2016.01.007, PMC4749444, 26832405, 26832405, S2211-1247(16)00027-9
Format: Citation

Title: Fine-sampled Photographic Quantitation of Dermal Wound Healing Senescence in Aged BALB/cByJ Mice and Therapeutic Intervention with FGF-1: Novel photographic quantitation of dermal healing.
Creator: Mellers, Alana, Tenorio, Connie, Lacatusu, Diana, Powell, Brett, Patel, Bhavi, Harper, Kathleen, Blaber, Michael
Abstract/Description: Objective: Determine quantitative parameters of dermal wound healing senescence in aged BALB/cByJ mice (an important animal model of aging) and evaluate the potential for therapeutic intervention by fibroblast growth factor-1 (FGF-1). Approach: Utilize a novel, non-invasive, fine-sampled photographic methodology to quantify wound healing parameters for healing phases from wounding through to wound closure. Results: Parameters associated with key healing phases were quantified and compared for...
Show moreObjective: Determine quantitative parameters of dermal wound healing senescence in aged BALB/cByJ mice (an important animal model of aging) and evaluate the potential for therapeutic intervention by fibroblast growth factor-1 (FGF-1). Approach: Utilize a novel, non-invasive, fine-sampled photographic methodology to quantify wound healing parameters for healing phases from wounding through to wound closure. Results: Parameters associated with key healing phases were quantified and compared for non-aged and aged cohorts of both sexes. The results identify a sexual dimorphism in dermal wound healing, with non-aged females exhibiting a greater overall healing efficiency compared to males. This enhanced healing in females, however, senesces with age such that healing parameters for aged males and females are statistically indistinguishable. Topical application of FGF-1 was identified as an effective therapeutic intervention to treat dermal healing senescence in aged females. Innovation: The FGF intervention is being analyzed using a new, recently published model. This approach significantly increases the amount of pre-clinical animal data obtainable in wound healing studies, minimizes cohort number compared to (lethal) histological studies, and permits a direct statistical comparison between different healing studies. Conclusion: Quantitative parameters of dermal wound healing, obtained from non-invasive fine-sampled photographic data, identify topical FGF-1 as an effective therapeutic to treat the senescence of dermal healing present in aged female BALB/cByJ mice.
Show less
Date Issued: 2018-06-25
Identifier: FSU_libsubv1_scholarship_submission_1529889363_21ee7933
Format: Citation

Title: Genotype-specific pathogenic effects in human dilated cardiomyopathy.
Creator: Bollen, Ilse A E, Schuldt, Maike, Harakalova, Magdalena, Vink, Aryan, Asselbergs, Folkert W, Pinto, Jose R, Krüger, Martina, Kuster, Diederik W D, van der Velden, Jolanda
Abstract/Description: Mutations in genes encoding cardiac troponin I (TNNI3) and cardiac troponin T (TNNT2) caused altered troponin protein stoichiometry in patients with dilated cardiomyopathy. TNNI3p.98trunc resulted in haploinsufficiency, increased Ca(2+) -sensitivity and reduced length-dependent activation. TNNT2p.K217del caused increased passive tension. A mutation in the gene encoding Lamin A/C (LMNAp.R331Q ) led to reduced maximal force development through secondary disease remodelling in patients suffering...
Show moreMutations in genes encoding cardiac troponin I (TNNI3) and cardiac troponin T (TNNT2) caused altered troponin protein stoichiometry in patients with dilated cardiomyopathy. TNNI3p.98trunc resulted in haploinsufficiency, increased Ca(2+) -sensitivity and reduced length-dependent activation. TNNT2p.K217del caused increased passive tension. A mutation in the gene encoding Lamin A/C (LMNAp.R331Q ) led to reduced maximal force development through secondary disease remodelling in patients suffering from dilated cardiomyopathy. Our study shows that different gene mutations induce dilated cardiomyopathy via diverse cellular pathways. Dilated cardiomyopathy (DCM) can be caused by mutations in sarcomeric and non-sarcomeric genes. In this study we defined the pathogenic effects of three DCM-causing mutations: the sarcomeric mutations in genes encoding cardiac troponin I (TNNI3p.98truncation ) and cardiac troponin T (TNNT2p.K217deletion ; also known as the p.K210del) and the non-sarcomeric gene mutation encoding lamin A/C (LMNAp.R331Q ). We assessed sarcomeric protein expression and phosphorylation and contractile behaviour in single membrane-permeabilized cardiomyocytes in human left ventricular heart tissue. Exchange with recombinant troponin complex was used to establish the direct pathogenic effects of the mutations in TNNI3 and TNNT2. The TNNI3p.98trunc and TNNT2p.K217del mutation showed reduced expression of troponin I to 39% and 51%, troponin T to 64% and 53%, and troponin C to 73% and 97% of controls, respectively, and altered stoichiometry between the three cardiac troponin subunits. The TNNI3p.98trunc showed pure haploinsufficiency, increased Ca(2+) -sensitivity and impaired length-dependent activation. The TNNT2p.K217del mutation showed a significant increase in passive tension that was not due to changes in titin isoform composition or phosphorylation. Exchange with wild-type troponin complex corrected troponin protein levels to 83% of controls in the TNNI3p.98trunc sample. Moreover, upon exchange all functional deficits in the TNNI3p.98trunc and TNNT2p.K217del samples were normalized to control values confirming the pathogenic effects of the troponin mutations. The LMNAp.R331Q mutation resulted in reduced maximal force development due to disease remodelling. Our study shows that different gene mutations induce DCM via diverse cellular pathways.
Show less
Date Issued: 2017-07-15
Identifier: FSU_pmch_28436080, 10.1113/JP274145, PMC5509872, 28436080, 28436080
Format: Citation

Title: An Examination of Dynamic Gene Expression Changes in the Mouse Brain During Pregnancy and the Postpartum Period.
Creator: Ray, Surjyendu, Tzeng, Ruei-Ying, DiCarlo, Lisa M, Bundy, Joseph L, Vied, Cynthia, Tyson, Gary, Nowakowski, Richard, Arbeitman, Michelle N
Abstract/Description: The developmental transition to motherhood requires gene expression changes that alter the brain to drive the female to perform maternal behaviors. We broadly examined the global transcriptional response in the mouse maternal brain, by examining four brain regions: hypothalamus, hippocampus, neocortex, and cerebellum, in virgin females, two pregnancy time points, and three postpartum time points. We find that overall there are hundreds of differentially expressed genes, but each brain region...
Show moreThe developmental transition to motherhood requires gene expression changes that alter the brain to drive the female to perform maternal behaviors. We broadly examined the global transcriptional response in the mouse maternal brain, by examining four brain regions: hypothalamus, hippocampus, neocortex, and cerebellum, in virgin females, two pregnancy time points, and three postpartum time points. We find that overall there are hundreds of differentially expressed genes, but each brain region and time point shows a unique molecular signature, with only 49 genes differentially expressed in all four regions. Interestingly, a set of "early-response genes" is repressed in all brain regions during pregnancy and postpartum stages. Several genes previously implicated in underlying postpartum depression change expression. This study serves as an atlas of gene expression changes in the maternal brain, with the results demonstrating that pregnancy, parturition, and postpartum maternal experience substantially impact diverse brain regions.
Show less
Date Issued: 2015-11-23
Identifier: FSU_pmch_26596646, 10.1534/g3.115.020982, PMC4704721, 26596646, 26596646, g3.115.020982
Format: Citation

Title: Experimental support for the foldability-function tradeoff hypothesis: segregation of the folding nucleus and functional regions in fibroblast growth factor-1..
Creator: Longo, Liam, Lee, Jihun, Blaber, Michael
Abstract/Description: The acquisition of function is often associated with destabilizing mutations, giving rise to the stability-function tradeoff hypothesis. To test whether function is also accommodated at the expense of foldability, fibroblast growth factor-1 (FGF-1) was subjected to a comprehensive φ-value analysis at each of the 11 turn regions. FGF-1, a β-trefoil fold, represents an excellent model system with which to evaluate the influence of function on foldability: because of its threefold symmetric...
Show moreThe acquisition of function is often associated with destabilizing mutations, giving rise to the stability-function tradeoff hypothesis. To test whether function is also accommodated at the expense of foldability, fibroblast growth factor-1 (FGF-1) was subjected to a comprehensive φ-value analysis at each of the 11 turn regions. FGF-1, a β-trefoil fold, represents an excellent model system with which to evaluate the influence of function on foldability: because of its threefold symmetric structure, analysis of FGF-1 allows for direct comparisons between symmetry-related regions of the protein that are associated with function to those that are not; thus, a structural basis for regions of foldability can potentially be identified. The resulting φ-value distribution of FGF-1 is highly polarized, with the majority of positions described as either folded-like or denatured-like in the folding transition state. Regions important for folding are shown to be asymmetrically distributed within the protein architecture; furthermore, regions associated with function (i.e., heparin-binding affinity and receptor-binding affinity) are localized to regions of the protein that fold after barrier crossing (late in the folding pathway). These results provide experimental support for the foldability-function tradeoff hypothesis in the evolution of FGF-1. Notably, the results identify the potential for folding redundancy in symmetric protein architecture with important implications for protein evolution and design.
Show less
Date Issued: 2012-12-01
Identifier: FSU_pmch_23047594, 10.1002/pro.2175, PMC3575920, 23047594, 23047594
Format: Citation

Title: Functional Role of Kallikrein 6 in Regulating Immune Cell Survival.
Creator: Scarisbrick, Isobel, Epstein, Benjamin, Cloud, Beth, Yoon, Hyesook, Wu, Jianmin, Renner, Danielle, Blaber, Sachiko, Blaber, Michael, Vandell, Alexander, Bryson, Alexandra
Abstract/Description: BACKGROUND: Kallikrein 6 (KLK6) is a newly identified member of the kallikrein family of secreted serine proteases that prior studies indicate is elevated at sites of central nervous system (CNS) inflammation and which shows regulated expression with T cell activation. Notably, KLK6 is also elevated in the serum of multiple sclerosis (MS) patients however its potential roles in immune function are unknown. Herein we specifically examine whether KLK6 alters immune cell survival and the...
Show moreBACKGROUND: Kallikrein 6 (KLK6) is a newly identified member of the kallikrein family of secreted serine proteases that prior studies indicate is elevated at sites of central nervous system (CNS) inflammation and which shows regulated expression with T cell activation. Notably, KLK6 is also elevated in the serum of multiple sclerosis (MS) patients however its potential roles in immune function are unknown. Herein we specifically examine whether KLK6 alters immune cell survival and the possible mechanism by which this may occur. METHODOLOGY/PRINCIPAL FINDINGS: Using murine whole splenocyte preparations and the human Jurkat T cell line we demonstrate that KLK6 robustly supports cell survival across a range of cell death paradigms. Recombinant KLK6 was shown to significantly reduce cell death under resting conditions and in response to camptothecin, dexamethasone, staurosporine and Fas-ligand. Moreover, KLK6-over expression in Jurkat T cells was shown to generate parallel pro-survival effects. In mixed splenocyte populations the vigorous immune cell survival promoting effects of KLK6 were shown to include both T and B lymphocytes, to occur with as little as 5 minutes of treatment, and to involve up regulation of the pro-survival protein B-cell lymphoma-extra large (Bcl-XL), and inhibition of the pro-apoptotic protein Bcl-2-interacting mediator of cell death (Bim). The ability of KLK6 to promote survival of splenic T cells was also shown to be absent in cell preparations derived from PAR1 deficient mice. CONCLUSION/SIGNIFICANCE: KLK6 promotes lymphocyte survival by a mechanism that depends in part on activation of PAR1. These findings point to a novel molecular mechanism regulating lymphocyte survival that is likely to have relevance to a range of immunological responses that depend on apoptosis for immune clearance and maintenance of homeostasis.
Show less
Date Issued: 2011
Identifier: FSU_migr_biomed_faculty_publications-0022, 10.1371/journal.pone.0018376
Format: Citation

Title: Function of microglia and macrophages in secondary damage after spinal cord injury.
Creator: Zhou, Xiang, He, Xijing, Ren, Yi
Abstract/Description: Spinal cord injury (SCI) is a devastating type of neurological trauma with limited therapeutic opportunities. The pathophysiology of SCI involves primary and secondary mechanisms of injury. Among all the secondary injury mechanisms, the inflammatory response is the major contributor and results in expansion of the lesion and further loss of neurologic function. Meanwhile, the inflammation directly and indirectly dominates the outcomes of SCI, including not only pain and motor dysfunction, but...
Show moreSpinal cord injury (SCI) is a devastating type of neurological trauma with limited therapeutic opportunities. The pathophysiology of SCI involves primary and secondary mechanisms of injury. Among all the secondary injury mechanisms, the inflammatory response is the major contributor and results in expansion of the lesion and further loss of neurologic function. Meanwhile, the inflammation directly and indirectly dominates the outcomes of SCI, including not only pain and motor dysfunction, but also preventingneuronal regeneration. Microglia and macrophages play very important roles in secondary injury. Microglia reside in spinal parenchyma and survey the microenvironment through the signals of injury or infection. Macrophages are derived from monocytes recruited to injured sites from the peripheral circulation. Activated resident microglia and monocyte-derived macrophages induce and magnify immune and inflammatory responses not only by means of their secretory moleculesand phagocytosis, but also through their influence on astrocytes, oligodendrocytes and demyelination. In this review, we focus on the roles of microglia and macrophages in secondary injury and how they contribute to the sequelae of SCI.
Show less
Date Issued: 2014-10-15
Identifier: FSU_pmch_25422640, 10.4103/1673-5374.143423, PMC4239768, 25422640, 25422640, NRR-9-1787
Format: Citation

Title: Functional Effects of a Restrictive-Cardiomyopathy-Linked Cardiac Troponin I Mutation (R145W) in Transgenic Mice.
Creator: Wen, Yuhui, Xu, Yuanyuan, Wang, Yingcai, Pinto, Jose, Potter, James, Kerrick, W.
Abstract/Description: The human cardiac troponin I (hcTnI) mutation R145W has been associated with restrictive cardiomyopathy. In this study, simultaneous measurements of ATPase activity and force in skinned papillary fibers from hcTnI R145W transgenic mice (Tg-R145W) were explored. Tg-R145W fibers showed an approximately 13-16% increase in maximal Ca(2+)-activated force and ATPase activity compared to hcTnI wild-type transgenic mice. The force-generating cross-bridge turnover rate (g) and the energy cost (ATPase...
Show moreThe human cardiac troponin I (hcTnI) mutation R145W has been associated with restrictive cardiomyopathy. In this study, simultaneous measurements of ATPase activity and force in skinned papillary fibers from hcTnI R145W transgenic mice (Tg-R145W) were explored. Tg-R145W fibers showed an approximately 13-16% increase in maximal Ca(2+)-activated force and ATPase activity compared to hcTnI wild-type transgenic mice. The force-generating cross-bridge turnover rate (g) and the energy cost (ATPase/force) were the same in all groups of fibers. Also, the Tg-R145W fibers showed a large increase in the Ca(2+) sensitivity of both force development and ATPase. In intact fibers, the mutation caused prolonged force and intracellular [Ca(2+)] transients and increased time to peak force. Analysis of force and Ca(2+) transients showed that there was a 40% increase in peak force in Tg-R145W muscles, which was likely due to the increased Ca(2+) transient duration. The above cited results suggest that: (1) there would be an increase in resistance to ventricular filling during diastole resulting from the prolonged force and Ca(2+) transients that would result in a decrease in ventricular filling (diastolic dysfunction); and (2) there would be a large (approximately 53%) increase in force during systole, which may help to partly compensate for diastolic dysfunction. These functional results help to explain the mechanisms by which these mutations give rise to a restrictive phenotype.
Show less
Date Issued: 2009
Identifier: FSU_migr_biomed_faculty_publications-0060, 10.1016/j.jmb.2009.07.080
Format: Citation

Search In

Pages

Pages

Sort Results By:

Narrow results by:

Collection

Topical Subject

Genre

Type of Resource

Language

Creator

Found In

Owner

Animals (125)	+ -
Humans (74)	+ -
Male (64)	+ -
Mice (48)	+ -
Female (39)	+ -

text (360)	+ -
journal article (295)	+ -
working paper (2)	+ -