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(申请人提供)：电压门控钠离子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)，它包含一个钙调蛋白(CaM)相互作用位点。因为钙离子是电活动的终极信号，经常被干扰 在疾病状态下，关键的钙传感器(CaM)在通道调节的热点(CTD)上的存在为理解这些通道病变如何导致疾病提供了一个起点。然而，钙/钙调素对Na+通道的调节知之甚少，而且由于缺乏结构信息和研究天然细胞类型的通道功能的挑战，信息受到限制。在这里，我们建立了新的结构信息和新的方法来研究钙/钙调素如何在天然细胞类型的背景下调节Na+通道。我们的新结构信息为研究无钙(Apo)CaM和钙负载CaM如何不同地影响通道功能、神经元和心脏通道在其天然细胞类型中如何被CaM明显调节以及Na+通道内不同的CaM相互作用结构域如何对整体钙/CaM依赖的调节做出贡献提供了背景和指导。我们研究心肌细胞和神经元中信息突变的新方法将有助于理解钙离子如何影响钠离子通道，从而了解钙离子调节失调如何导致各种钠离子通道病变。本研究的具体目标是确定：1)无钙apoCaM如何控制神经元和心肌细胞的NAV功能；2)Ca2+/CaM与NAV CTD的相互作用如何控制神经元和心肌细胞的NAV功能；以及3)钙/CaM与NAV III-IV细胞内连接子的相互作用如何控制神经元和心肌细胞的NAV功能。