CaMKII-dependent regulation of cardiac excitability

CaMKII 依赖性心脏兴奋性调节

• 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
• 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

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）：可激发的细胞功能取决于高度进化的局部信号传导域，这些信号域对离子通道，转运蛋白和受体的翻译后修饰（例如磷酸化，氧化）进行紧密的时间和时间控制。这些局部信号域的破坏和/或膜蛋白翻译后修饰的改变与先天性和获得形式的心脏病（包括心力衰竭）的心律不齐的易感性增加有关。我们的研究试图了解负责特定亚细胞域中膜蛋白局部调节的细胞途径，其总体目的是对人类心律不齐和猝死产生新的见解。 CAMKII是一种多功能丝氨酸/苏氨酸激酶，可调节心脏中关键细胞功能的广泛范围。尽管CaMKII对于心脏功能很重要，但关于局部结构域的生物发生以控制CAMKII信号传导知之甚少。我们最近证明，与肌动蛋白相关的多肽β-光谱蛋白是一种新型的CAMKII粘液蛋白（CAMKAP），该蛋白（CAMKAP）将CAMKII靶向插入的盘以调节电压门控的Na+通道（NAV）功能和心脏兴奋性。但是，将betaiv-spectrin/camkii连接到插入式椎间盘的NAV1.5的分子途径以及CAMKII改变NAV1.5功能的机制仍然未知。此外，未探索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障碍（心律不齐）中的作用。我们的初步数据表明，β-谱蛋白可以用辅助蛋白Ankyrin-g和Nav1.5在互嵌片上组织CAMKII的脚手架。我们还确定了负责CAMKII依赖性NAV功能调节的NAV1.5（SER571）上的潜在位点，并开发了新的试剂来研究该位点在原发性肌细胞中的作用。此外，我们已经确定了与CAMKII磷酸化基序相邻的人类变体簇的机制，该基序通过破坏正常通道调节来赋予心律不齐的敏感性。最后，我们的初步结果表明，nav1.5的CaMKII依赖性磷酸化失调发生在心脏病的鼠和犬类模型中，以及人类心脏失败。总的来说，这些初步数据支持了我们的中心假设，即β-光谱蛋白在心肌细胞中组织一个局部膜域，以控制NAV1.5的CAMKII依赖性磷酸化，而CAMKII调节基序在NAV1.5中是与持续性的关键点相关的nadal nadal nadal inder hydhy indy naidy Channel Channel anders Channel indress inders Charder in Droperse carde inders canders carde indys canders inders canders inders canders inders cardias的关键点的关键点。我们预计，CAMKII/Spectrin相互作用的目标破坏将防止CaMKII依赖性NAV1.5的磷酸化，减轻心律失常负担并改善心肌侮辱的心脏功能。我们预计，这些研究将对CAMKII信号传导域的组织产生新的见解，定义调节NAV1.5的分子途径和细胞兴奋性，并确定先天性和获得性心脏病中心律不齐的新型机制。 公共卫生相关性：心脏电动障碍（心律不齐）每年对40万与心脏有关的死亡中的大多数造成造成造成的大多数。在细胞水平， 异常的膜兴奋性增加了对潜在致命心律不齐的敏感性。这些研究将确定调节心脏细胞膜兴奋性的分子途径，并将对先天性和普通获得形式的心律失常形式产生新的见解。