Molecular Physiology of KCNE Potassium Channel Subunits

KCNE 钾通道亚基的分子生理学

• 批准号: 7417808
• 负责人: Alfred L. George
• 金额: $ 36.39万
• 依托单位: VANDERBILT UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-05-15 至 2010-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7417808
• 关键词: Adenoviruses; Adult; Affect; Arrhythmia; Biochemical; Canis familiaris; Cardiac; Cardiac Myocytes; Catalytic RNA; Cells; Chimera organism; Chronic; Class; Cleaved cell; Complex; Condition; Coupled; Cultured Cells; Disease; Family; Functional disorder; Gene Silencing; Generations; Genes; Heart; Heart Diseases; Heart Transplantation; Heart failure; Human; Human Genome; In Vitro; Inborn Genetic Diseases; Integral Membrane Protein; Knowledge; Measures; Mink; Modeling; Molecular; Mus; Muscle Cells; Mutation; Myocardial; Neonatal; Patients; Pattern; Peptides; Phenotype; Physiological; Physiology; Potassium; Potassium Channel; Predisposition; Property; Proteins; RNA; RNA Interference; Range; Recombinants; Regulation; Relative (related person); Research Personnel; Skeletal Muscle; System; Testing; Time; Tissues; Torsades de Pointes; Ventricular Arrhythmia; in vivo; interest; multidisciplinary; mutant; programs; reconstitution; research study; voltage

DESCRIPTION (provided by applicant): Voltage-gated potassium (Kv) channels are modulated by at least three distinct classes of accessory proteins including the KCNE family of single transmembrane proteins. In the human genome, KCNE proteins are encoded by five genes designated KCNE1 through KCNE5. The physiological importance of three KCNE genes has been demonstrated by associations with inherited disorders of cardiac and skeletal muscle excitability. Mutation of KCNE 1 impairs generation of the slowly activating cardiac delayed rectifier current (IKS), a critical potassium current contributing to myocardial repolarization that can be reconstituted in vitro by heterologous co-expression of recombinant KCNQ1 potassium channels with KCNE1. Other KCNE proteins also exert diverse functional effects on heterologously expressed KCNQ1. Co-expression of KCNQ1 with KCNE3, KCNE4 or KCNE5 is particularly interesting with functional effects ranging from constitutive activation (KCNE3) to suppression (KCNE4, KCNE5). We have recently demonstrated that all KCNE genes are expressed in human cardiac myocytes to varying degrees. We have further demonstrated that KCNE4 and KCNE5 exert potent inhibitory influences on heterologously expressed IKappaS and KCNE4 appears dominant over KCNE1 in this context. In addition to potential interactions with KCNQ1, KCNE proteins affect the functional properties of other cloned potassium channels. The physiological relevance of these in vitro observations remains uncertain. The observations that multiple KCNE proteins can modulate KCNQ1 channels to produce diverse biophysical phenotypes raises several intriguing questions with important implications for understanding the regulation of IKS as well as other potassium currents in normal and diseased heart. Can different KCNE subtypes compete functionally with KCNE1 for modulation of KCNQ1? Can KCNQ1 associate with more than one KCNE subtype in the same cell and at the same time? Do KCNE4 and KCNE5 participate in the pathophysiology of heart failure and other arrhythmia-prone conditions? In this proposal, we outline several experimental approaches for defining the physiological importance of KCNE subunits with a particular focus on KCNE4 and KCNE5. In Specific Aim 1, we will use a heterologous expression system to assess the range of functional and biochemical interactions possible between KCNQ1 and different KCNE subunits with a focus on KCNE4 and KCNE5. In Specific Aim 2, we will test the hypothesis that KCNE4 and KCNE5 are physiologically significant regulators of potassium currents in native cardiac myocytes by using two independent gene silencing approaches. Finally in Specific Aim 3, we will examine expression patterns of KCNQ1 and KCNE genes in diseased human heart and in an experimental canine model of ventricular arrhythmia susceptibility. Results from these studies will have implications for advancing our knowledge of the complex interplay between pore-forming and accessory subunits that comprise human potassium channels expressed in the heart and in other tissues.

描述（由申请人提供）：电压门控钾（Kv）通道由至少三种不同类型的辅助蛋白调节，包括单跨膜蛋白的KCNE家族。在人类基因组中，KCNE蛋白由五个基因编码，命名为KCNE1至KCNE5。三个KCNE基因的生理重要性已经通过与心脏和骨骼肌兴奋性的遗传性疾病的关联而被证明。KCNE 1的突变损害了缓慢激活的心脏延迟整流电流（IKS）的产生，IKS是一种促进心肌复极的关键钾电流，可以通过重组KCNQ 1钾通道与KCNE 1的异源共表达在体外重建。其他KCNE蛋白质也发挥不同的功能异源表达KCNQ1的影响。KCNQ1与KCNE3、KCNE4或KCNE5的共表达特别令人感兴趣，其功能效应范围从组成性激活（KCNE3）到抑制（KCNE4、KCNE5）。我们最近证明，所有KCNE基因在人心肌细胞中表达不同程度。我们进一步证明了KCNE4和KCNE5对异源表达的IKappaS产生有效的抑制作用，在这种情况下，KCNE4似乎比KCNE1占优势。除了与KCNQ1的潜在相互作用外，KCNE蛋白还影响其他克隆钾通道的功能特性。这些体外观察结果的生理相关性仍不确定。 多种KCNE蛋白可以调节KCNQ1通道产生不同的生物物理表型的观察结果提出了几个有趣的问题，对理解IKS以及正常和患病心脏中其他钾电流的调节具有重要意义。不同的KCNE亚型是否能与KCNE1竞争调节KCNQ1的功能？KCNQ1可以在同一细胞中同时与多个KCNE亚型结合吗？KCNE4和KCNE5是否参与心力衰竭和其他易患糖尿病的疾病的病理生理学？ 在这个建议中，我们概述了几种实验方法，用于定义KCNE亚基的生理重要性，特别关注KCNE4和KCNE5。在具体目标1中，我们将使用异源表达系统来评估KCNQ1和不同KCNE亚基之间可能的功能和生化相互作用的范围，重点是KCNE4和KCNE5。在具体目标2中，我们将通过使用两种独立的基因沉默方法来检验KCNE4和KCNE5是天然心肌细胞中钾电流的生理学显著调节剂的假设。最后，在具体目标3中，我们将研究KCNQ1和KCNE基因在患病人类心脏和实验室心律失常易感性犬模型中的表达模式。这些研究的结果将有助于我们进一步了解孔形成亚基和辅助亚基之间的复杂相互作用，这些亚基包括在心脏和其他组织中表达的人钾通道。

项目成果

Association of a common KCNE1 variant with heart failure.

常见 KCNE1 变异与心力衰竭的关联。

• DOI: 10.1016/j.hrthm.2009.12.014
• 发表时间: 2010
• 期刊: Heart rhythm
• 影响因子: 5.5
• 作者: GeorgeJr,AlfredL

Distinct subdomains of the KCNQ1 S6 segment determine channel modulation by different KCNE subunits.

• DOI: 10.1085/jgp.200910234
• 发表时间: 2009-09
• 期刊: The Journal of general physiology
• 作者: Vanoye CG;Welch RC;Daniels MA;Manderfield LJ;Tapper AR;Sanders CR;George AL Jr
• 通讯作者: George AL Jr

Structure of KCNE1 and implications for how it modulates the KCNQ1 potassium channel.

• DOI: 10.1021/bi800875q
• 发表时间: 2008-08-05
• 期刊: BIOCHEMISTRY
• 影响因子: 2.9
• 作者: Kang, Congbao;Tian, Changlin;Soennichsen, Frank D.;Smith, Jarrod A.;Meiler, Jens;George, Alfred L., Jr.;Vanoye, Carlos G.;Kim, Hak Jun;Sanders, Charles R.
• 通讯作者: Sanders, Charles R.