A Molecular Target for Atrial Fibrillation

心房颤动的分子靶点

• 批准号: 6900267
• 负责人: KATHERINE T MURRAY
• 金额: $ 37.75万
• 依托单位: VANDERBILT UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-07-15 至 2008-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6900267
• 关键词: A kinase anchoring protein; SDS polyacrylamide gel electrophoresis; atrial fibrillation; atrium; biological signal transduction; clinical research; electrophysiology; heart electrical activity; human tissue; immunoprecipitation; laboratory rat; mass spectrometry; potassium channel; protein kinase A; protein protein interaction; protein structure function; proteomics; voltage /patch clamp; western blottings

DESCRIPTION (provided by applicant): Atrial fibrillation is the most common sustained cardiac arrhythmia in the United States, and it remains a major source of morbidity and mortality in this country. Antiarrhythmic drugs currently available to treat this arrhythmia are often ineffective, and they can create serious proarrhythmia because ion channels in the ventricle are affected. The goal of this proposal is to investigate the molecular basis of an atrial-specific ultrarapid K+ current, IKur, a potential target for pharmacologic therapy of atrial fibrillation. While the Kv 1.5 gene product is an important component of IKur, our preliminary data indicate that this alpha-subunit cannot fully recapitulate the native K+ current. In the proposed specific aims, we will test the hypothesis that IKur is a macromolecular complex composed of multiple channel subunits, signaling molecules, and additional proteins that can modify channel function. The Kv 1.5 complex will be isolated from human atrium, and associated K+ channel alpha and/or beta-subunits will be identified using antibody-based methods. Following heterologous expression of the proteins identified, electrophysiologic techniques will be used to confirm if the resultant K+ current phenotype is that of IKur. Additional experiments will determine whether chamber and disease-specific alterations in the channel complex occur. An analogous strategy will be used to determine the role of A-kinase anchoring proteins (AKAPs) in the Kv 1.5 signaling complex. We will also test the hypothesis generated by our preliminary data that a Kv beta subunit can function as an AKAP. Finally, a proteomics approach will be employed to identify previously unknown protein partners in the Kv 1.5 complex, with protein-protein interactions validated using standard biochemical approaches. This technology will also be used to confirm associated Kv subunits and signaling molecules. The knowledge gained from these studies will improve our understanding of the molecular components of atrial electrophysiology and facilitate the development of novel strategies in the treatment of atrial fibrillation.

描述（由申请人提供）：心房颤动是美国最常见的持续性心律失常，它仍然是美国发病率和死亡率的主要来源。目前可用于治疗这种心律失常的抗心律失常药物往往无效，并且由于心室中的离子通道受到影响，它们可能造成严重的心律失常。本提案的目的是研究心房特异性超快K+电流IKur的分子基础，IKur是房颤药物治疗的潜在靶点。虽然Kv 1.5基因产物是IKur的重要组成部分，但我们的初步数据表明，该α亚基不能完全再现天然K+电流。在提出的具体目标中，我们将测试IKur是由多个通道亚基、信号分子和可以改变通道功能的其他蛋白质组成的大分子复合物的假设。Kv 1.5复合体将从人心房分离，相关的K+通道α和/或β亚基将使用基于抗体的方法鉴定。在鉴定的蛋白异源表达后，电生理技术将用于确认所得到的K+电流表型是否为IKur表型。进一步的实验将确定通道复合体是否发生腔室和疾病特异性改变。类似的策略将用于确定a激酶锚定蛋白（AKAPs）在Kv 1.5信号复合体中的作用。我们还将测试由我们的初步数据产生的假设，即Kv β亚基可以作为AKAP起作用。最后，将采用蛋白质组学方法鉴定Kv 1.5复合体中以前未知的蛋白质伴侣，并使用标准生化方法验证蛋白质-蛋白质相互作用。该技术还将用于确认相关的Kv亚基和信号分子。从这些研究中获得的知识将提高我们对心房电生理分子成分的理解，并促进心房颤动治疗新策略的发展。