CaMKII-dependent regulation of cardiac excitability

CaMKII 依赖性心脏兴奋性调节

基本信息

批准号：
8343267
负责人：
Thomas Jeffrey Hund
金额：
$ 38.13万
依托单位：
OHIO STATE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2012
资助国家：
美国
起止时间：
2012-09-01 至 2017-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8343267
关键词：
Abnormal Cell Actins Address Animal Model Ankyrins Arrhythmia Biogenesis Canis familiaris Cardiac Cardiac Myocytes Cell membrane Cell physiology Cells Cessation of life Complex Data Figs - dietary Genetic Transcription Heart Heart Diseases Heart failure Human Intercalated disc Ion Channel Link Membrane Membrane Proteins Modeling Molecular Mus Muscle Cells Myocardial Nodal Pathway interactions Patients Phosphorylation Post-Translational Protein Processing Predisposition Protein-Serine-Threonine Kinases Proteins Reagent Regulation Research Role Signal Transduction Site Spectrin Sudden Death United States Variant adapter protein base betaIV spectrin calmodulin-dependent protein kinase II disease phenotype heart function improved innovation insight new therapeutic target novel oxidation polypeptide prevent receptor scaffold tool voltage

项目摘要

DESCRIPTION (provided by applicant): Excitable cell function depends on highly evolved local signaling domains that exert tight spatial and temporal control over post-translational modification (e.g. phosphorylation, oxidation) of ion channels, transporters and receptors. Disruption of these local signaling domains and/or alterations in post-translational modification of membrane proteins are associated with increased susceptibility to arrhythmia in congenital and acquired forms of heart disease, including heart failure. Our research seeks to understand the cellular pathways responsible for local regulation of membrane proteins in specific subcellular domains with the overall objective of generating new insight into human cardiac arrhythmia and sudden death. CaMKII is a multifunctional serine/threonine kinase that regulates a broad spectrum of critical cellular functions in heart. Despite the importance of CaMKII for heart function, little is known regarding the biogenesis of local domains to control CaMKII signaling. We recently demonstrated that the actin-associated polypeptide betaIV-spectrin serves as a novel CaMKII-anchoring protein (CaMKAP), which targets CaMKII to the intercalated disc for regulation of voltage-gated Na+ channel (Nav) function and cardiac excitability. However, the molecular pathway linking betaIV-spectrin/CaMKII to Nav1.5 at the intercalated disc, and mechanisms by which CaMKII alters Nav1.5 function remain unknown. Moreover, the role for CaMKII-dependent regulation of Nav1.5 and cell excitability in heart disease and potentially fatal electrical rhythm disturbances (arrhythmias) is unexplored. Our preliminary data indicate that betaIV-spectrin acts as a scaffold for organizing CaMKII with the adapter protein ankyrin-G and Nav1.5 at the intercalated disc. We have also identified a potential site on Nav1.5 (Ser571) responsible for CaMKII-dependent regulation of Nav function and have developed new reagents to study the role of this site in primary myocytes. Furthermore, we have identified the mechanism for a cluster of human variants adjacent to the CaMKII phosphorylation motif that confer susceptibility to arrhythmia by disrupting normal channel regulation. Finally, our preliminary results indicate that dysregulation of CaMKII-dependent phosphorylation of Nav1.5 occurs in murine and canine models of heart disease, and in failing human hearts. Collectively, these preliminary data support our central hypothesis that betaIV-spectrin organizes a local membrane domain at the cardiomyocyte intercalated disc to control CaMKII-dependent phosphorylation of Nav1.5, and that the CaMKII regulatory motif in Nav1.5 is a critical nodal point for regulating channel function in diverse forms of cardiac disease associated with arrhythmias and sudden death. We expect that targeted disruption of CaMKII/spectrin interaction will prevent CaMKII-dependent phosphorylation of Nav1.5, decrease arrhythmia burden and improve heart function in the setting of myocardial insult. We anticipate that these studies will generate new insight into organization of CaMKII signaling domains, define molecular pathways for regulation of Nav1.5 and cell excitability, and identify novel mechanisms for arrhythmias in both congenital and acquired heart disease. PUBLIC HEALTH RELEVANCE: Cardiac electrical disturbances (arrhythmias) are responsible for most of the 400,000 heart related deaths each year in the United States. At the cellular level, abnormal membrane excitability increases susceptibility to potentially fatal cardiac arrhythmias. These studies will identify molecular pathways for regulation of cell membrane excitability in heart and will generate new insight into mechanisms underlying congenital and common acquired forms of cardiac arrhythmia.

描述（由申请人提供）：可兴奋的细胞功能取决于高度进化的局部信号传导域，这些信号传导域对离子通道、转运蛋白和受体的翻译后修饰（例如磷酸化、氧化）施加严格的空间和时间控制。这些局部信号传导域的破坏和/或膜蛋白翻译后修饰的改变与先天性和获得性心脏病（包括心力衰竭）中心律失常的易感性增加有关。我们的研究旨在了解负责特定亚细胞域中膜蛋白局部调节的细胞途径，总体目标是对人类心律失常和猝死产生新的见解。 CaMKII 是一种多功能丝氨酸/苏氨酸激酶，可调节心脏中多种关键细胞功能。尽管 CaMKII 对心脏功能很重要，但关于控制 CaMKII 信号传导的局部结构域的生物发生却知之甚少。我们最近证明，肌动蛋白相关多肽 betaIV-血影蛋白可作为一种新型 CaMKII 锚定蛋白 (CaMKAP)，它将 CaMKII 靶向闰盘，以调节电压门控 Na+ 通道 (Nav) 功能和心脏兴奋性。然而，在闰盘处将 betaIV-血影蛋白/CaMKII 与 Nav1.5 连接的分子途径，以及 CaMKII 改变 Nav1.5 功能的机制仍然未知。此外，CaMKII 依赖性调节 Nav1.5 和细胞兴奋性在心脏病和潜在致命的电节律紊乱（心律失常）中的作用尚未被探索。我们的初步数据表明，βIV-血影蛋白充当在闰盘处组织 CaMKII 与衔接蛋白锚蛋白-G 和 Nav1.5 的支架。我们还鉴定了 Nav1.5 (Ser571) 上负责 CaMKII 依赖性 Nav 功能调节的潜在位点，并开发了新试剂来研究该位点在原代肌细胞中的作用。此外，我们还确定了与 CaMKII 磷酸化基序相邻的一组人类变异的机制，这些变异通过破坏正常的通道调节而导致对心律失常的易感性。最后，我们的初步结果表明，CaMKII 依赖性 Nav1.5 磷酸化的失调发生在小鼠和犬类心脏病模型以及人类心脏衰竭中。总的来说，这些初步数据支持我们的中心假设，即 betaIV-血影蛋白在心肌细胞闰盘组织局部膜结构域来控制 Nav1.5 的 CaMKII 依赖性磷酸化，并且 Nav1.5 中的 CaMKII 调节基序是 Nav1.5 的关键节点。在与心律失常和猝死相关的多种心脏病中调节通道功能。我们预计，有针对性地破坏 CaMKII/血影蛋白相互作用将阻止 Nav1.5 的 CaMKII 依赖性磷酸化，减少心律失常负担并改善心肌损伤情况下的心功能。我们预计这些研究将对 CaMKII 信号域的组织产生新的见解，定义 Nav1.5 和细胞兴奋性调节的分子途径，并确定先天性和获得性心脏病中心律失常的新机制。公共卫生相关性：在美国，每年 40 万人因心脏相关死亡，其中大部分是由心脏电紊乱（心律失常）造成的。在细胞水平上，膜兴奋性异常会增加潜在致命性心律失常的易感性。这些研究将确定心脏细胞膜兴奋性调节的分子途径，并将对先天性和常见后天性心律失常的机制产生新的见解。