Dynamic Calmodulin Regulation of Na Channels

Na 通道的动态钙调蛋白调节

• 批准号: 8604637
• 负责人: DAVID T YUE
• 金额: $ 37.88万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-02-01 至 2016-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8604637
• 关键词: Allosteric Regulation; Arrhythmia; Binding; Biochemistry; Biological; Biology; Calmodulin; Cells; Clinical; Data; Dialysis procedure; Disease; Engineering; Epilepsy; Esthesia; Exhibits; Family; Fluorescence Resonance Energy Transfer; Hand; Health; Investigation; Laboratories; Life; Link; Lobe; Mediating; Molecular; Muscle; Muscle Contraction; Mutation; Myotonia; Physiological; Physiology; Protein Isoforms; Recombinants; Regulation; Reporting; Research; SCN1A protein; Seizures; Signal Transduction; Site; System; Testing; Translating; Variant; base; disease phenotype; improved; innovation; interest; novel; painful neuropathy; research study; response; screening; stoichiometry; structural biology; trafficking; voltage

DESCRIPTION (provided by applicant): Calmodulin (CaM) regulation of four-domain channels first emerged in CaV channels, and has proved rich both mechanistically and biologically. Our laboratory has been one of the leaders in unveiling this exciting chapter of CaV channel discovery. Given the sequence similarity of CaV and NaV channels, intriguing suspicions arose that NaV channels might also exhibit such CaM regulation. This possibility was most attractive, given the wide-ranging biological and clinical impact of NaV channels, which include mentation (epilepsy), muscle contraction (myotonia and arrhythmias), and sensation (neuropathic pain). Biochemistry and structural biology both underscored this similarity, but the reported functional effects of Ca2+ and/or CaM on NaV channels have been rather subtle, mostly limited to several-mV shifts of steady-state inactivation (h%) curves. Yet, channelopathic NaV mutations at putative structural determinants of Ca2+ and/or CaM regulation do confer severe disease phenotypes. One potential culprit for the apparent disconnect is that, unlike CaV channels, NaV channels do not conduct Ca2+, so they cannot directly trigger Ca2+ responses. Instead, the NaV field has used whole-cell dialysis to tonically manipulate Ca2+ levels, over several minutes or longer. Could the field be characterizing desensitized responses to Ca2+ and/or CaM, with poor similarity to short-term and larger physiological effects? Here, we use a different approach to dynamically perturb Ca2+, and our preliminary data unveil something long sought in the field>rapid and robust Ca2+/CaM-dependent inactivation of NaV channels (CDI). The advances now permitted may revolutionize understanding of the CaM regulation of NaV channels. This project will usher in an exciting era of discovery via three specific aims. (1) To unveil the existence of rapid Ca2+/CaM-mediated regulation across the family of NaV channels. (2) To elucidate the mechanism of dynamic CaM-mediated regulation of NaV channels. With long-sought robust readouts of NaV regulation in hand, Aim 2 will be uniquely poised to dissect the mechanistic underpinnings of regulation. (3) To assess the broader biological impact of CaM-mediated regulation of Nav channels. The mechanistic advances above hold numerous biological implications that Aim 3 will explore. In all, this project will facilitate a period of unprecedented progress in the Ca2+ regulation of NaV channels. As well, this proposal will explicitly link Ca2+ regulation of NaV channels to certain channelopathies, and perhaps to related but more generalized forms of disease.

描述（由申请人提供）：钙调蛋白（CAM）对四域通道的调节首先出现在CAV通道中，并在机械和生物学上证明了富含富含的通道。我们的实验室一直是揭开Cav Channel Discovery这一令人兴奋的一章的领导者之一。鉴于CAV和NAV通道的序列相似性，引起人们的怀疑引起了NAV通道也可能表现出这种CAM调节。鉴于NAV通道对生物学和临床的广泛影响，这种可能性是最吸引人的，其中包括INTHITITATIT（癫痫），肌肉收缩（肌瘤和心律不齐）和感觉（神经性疼痛）。生物化学和结构生物学都强调了这种相似性，但是CA2+和/或CAM对NAV通道的功能效应非常微妙，大多限于稳态失活（H％）曲线的几种MV变化。然而，CA2+和/或CAM调节的假定结构决定因素的通道病NAV突变确实提供了严重的疾病表型。明显断开连接的一种潜在罪魁祸首是，与CAV通道不同，NAV通道不会进行CA2+，因此它们不能直接触发Ca2+​​响应。取而代之的是，NAV场在几分钟或更长时间内使用了全细胞透析来操纵Ca2+水平。该领域是否可以表征对Ca2+和/或CAM的脱敏反应，与短期和更大的生理效应相似？在这里，我们使用一种动态扰动Ca2+的不同方法，我们的初步数据在现场>快速且坚固的Ca2+/CAM依赖性依赖于NAV通道（CDI）中一直寻求的东西。现在允许的进步可能会彻底改变对NAV渠道的CAM调节的理解。该项目将通过三个特定目标吸引一个令人兴奋的发现时代。 （1）揭示了整个NAV通道家族的CA2+/CAM介导的快速调节。 （2）阐明了动态CAM介导的NAV通道调节机理。借助长期以来对NAV调节的强大读数，AIM 2将被唯一准备剖析调节的机械基础。 （3）评估CAM介导的NAV通道调节的更广泛的生物学影响。上面的机械进步具有AIM 3将探索的许多生物学含义。总的来说，该项目将促进NAV通道的CA2+调节中前所未有的进展。同样，该建议将明确将CA2+ NAV通道的调节与某些通道病的调节联系起来，并可能与相关但更广泛的疾病形式联系起来。