Calmodulin regulation of Na+ channels in neurons and cardiomyocytes

钙调蛋白对神经元和心肌细胞Na通道的调节

• 批准号: 8965516
• 负责人: Steven O Marx
• 金额: $ 51.43万
• 依托单位: DUKE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-11-15 至 2016-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8965516
• 关键词: Action Potentials; Address; Affect; Affinity; Arrhythmia; Ataxia; Autistic Disorder; Binding; Biochemical; C-terminal; Calmodulin; Cardiac; Cardiac Myocytes; Cardiomyopathies; Cells; Conflict (Psychology); Data; Disease; Epilepsy; Feedback; Functional disorder; Gap Junctions; Genes; Grant; Health; Inherited; Intellectual functioning disability; Knowledge; Lead; Ligand Binding Domain; Link; Mediator of activation protein; Membrane; Methods; Modeling; Mutate; Mutation; Neurons; Pathologic; Physiological; Physiology; Process; Regulation; Resolution; Role; SCN1A protein; SCN2A protein; Schizophrenia; Signal Transduction; Site; Structure; Sudden infant death syndrome; Syndrome; System; Testing; Time; cell type; disease-causing mutation; innovation; mutant; novel; novel strategies; sensor; voltage

DESCRIPTION (provided by applicant): Voltage-gated Na+ channelopathies are associated with multiple disorders. Mutations in neuronal Na+ channels cause epilepsy syndromes, ataxia, and autism; mutations in the cardiac Na+ channels are associated with arrhythmias, sudden infant death syndrome, conduction disorders, and cardiomyopathies. A hotspot for disease-causing mutations is the channels' C-terminal domain (CTD), which harbors a calmodulin (CaM) interaction site. Because Ca2+ is the ultimate signal of electrical activity and is often perturbed in disease states, the presence of a key Ca2+ sensor (CaM) at a hotspot for channel regulation (the CTD) provides a starting point for understanding how these channelopathies cause disease. Nevertheless, regulation of Na+ channels by Ca2+/CaM is poorly understood and information is limited by the lack of structural information and challenges to investigating channel function in native cell types. Here, we build on new structural information and novel methods to investigate how Ca2+/CaM regulates Na+ channels in the context of native cell types. Our new structural information provides background and guideposts for investigating how Ca2+-free (apo) CaM and Ca2+-loaded CaM differently affect channel function; how neuronal and cardiac channels are distinctly regulated by CaM in their native cell types, and how different CaM interacting domains within Na+ channels contribute to overall Ca2+/CaM-dependent regulation. Our novel methods of studying informative mutants in cardiomyocytes and neurons will provide an understanding of how Ca2+ affects Na+ channels and thus how Ca2+ dysregulation leads to the various Na+ channelopathies. The specific Aims addressed in this proposal are to determine: 1) How Ca2+-free apoCaM controls NaV function in neurons and cardiomyocytes; 2) How Ca2+/CaM interaction with the NaV CTD controls NaV function in neurons and cardiomyocytes; and 3) How Ca2+/CaM interaction with the NaV III-IV intracellular linker controls NaV function in neurons and cardiomyocytes.

描述（由申请方提供）：电压门控Na+通道病与多种疾病相关。神经元Na+通道的突变会导致癫痫综合征、共济失调和自闭症;心脏Na+通道的突变与心律失常、婴儿猝死综合征、传导障碍和心肌病有关。致病突变的一个热点是通道的C-末端结构域（CTD），它含有钙调蛋白（CaM）相互作用位点。因为Ca 2+是电活动的最终信号， 在疾病状态下，在通道调节的热点（CTD）处存在关键的Ca 2+传感器（CaM）为理解这些通道病如何引起疾病提供了起点。然而，调节Na+通道的Ca 2 +/CaM是知之甚少，信息是有限的，缺乏结构信息和挑战，调查在天然细胞类型的通道功能。在这里，我们建立在新的结构信息和新的方法来研究如何Ca 2 +/CaM调节Na+通道的背景下，天然细胞类型。我们的新结构信息提供了背景和路标，调查如何无钙（载脂蛋白）钙调素和钙调素不同地影响通道功能;如何神经元和心脏通道明显调节钙调素在其天然细胞类型，以及如何不同的钙调素相互作用的Na+通道内的结构域有助于整体钙/钙调素依赖性调节。我们研究心肌细胞和神经元中的信息突变体的新方法将提供对Ca 2+如何影响Na+通道的理解，从而了解Ca 2+失调如何导致各种Na+通道病。本提案的具体目的是确定：1）无Ca 2 + apoCaM如何控制神经元和心肌细胞中的NaV功能; 2）Ca 2 +/CaM与NaV CTD的相互作用如何控制神经元和心肌细胞中的NaV功能; 3）Ca 2 +/CaM与NaV III-IV细胞内连接体的相互作用如何控制神经元和心肌细胞中的NaV功能。