Gating Mechanisms of KCNQ1/IKS Channels

KCNQ1/IKS 通道的门控机制

• 批准号: 10491284
• 负责人: Jianmin Cui
• 金额: $ 62.58万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-20 至 2025-08-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10491284
• 关键词: Action Potentials; Anti-Arrhythmia Agents; Arrhythmia; Binding; Binding Sites; Calmodulin; Cardiac; Cardiac Electrophysiologic Techniques; Cartoons; Cell Line; Cells; Complex; Coupling; Cryoelectron Microscopy; Data; Development; Electrophysiology (science); Family member; Fluorescence Resonance Energy Transfer; Fluorescence Spectroscopy; Goals; Heart; Human; Interruption; Lead; Left; Lobe; Mammalian Cell; Mediating; Membrane; Membrane Lipids; Molecular; Molecular Conformation; Motion; Mutagenesis; Mutate; Oranges; Pharmaceutical Preparations; Phosphatidylinositol 4,5-Diphosphate; Phosphatidylinositols; Physiological; Play; Potassium Channel; Process; Proteins; Publishing; Rest; Role; Rotation; Signal Transduction; Site; Structure; Surface; Testing; Xenopus oocyte; alpha helix; cofactor; design; drug development; experimental study; fluorophore; heart rhythm; improved; novel; prevent; sensor; simulation; trafficking; voltage

Project Summary This project is to reveal the mechanism of how voltage, phosphatidylinositol 4,5-bisphosphate (PIP2) and calmodulin (CaM) integrate to activate the IKs potassium ion channels in the heart. The IKs channel is important for repolarization of cardiac action potentials and the control of heart rhythm. CaM and the membrane lipid PIP2 are important cell signals, and meanwhile these molecules are cofactors of the IKs channel required for channel opening. These enable the IKs channel to play a critical role in the adaptation of heart rhythm to various physiological conditions. Congenital and drug induced IKs malfunction is associated with cardiac arrhythmias. Previous studies and our preliminary data indicate that the IKs channel is a novel target for antiarrhythmic therapy. The significance of this study is to improve the understanding of molecular basis of cardiac electrophysiology and antiarrhythmic drug development. At present how CaM and PIP2 interact with the IKs channel is not clear. This proposal is motivated by the recently published structural data of the channel protein. Combining these data with other published and our preliminary studies lead to an exciting hypothesis for how CaM, PIP2 and voltage integrate to activate the IKs channels. Our specific aims are designed to examine three key aspects of this hypothesis. We will use electrophysiological approaches, fluorescence spectroscopy, structure-informed mutagenesis and molecular dynamic simulations to study the IKs channels expressed in exogenous expression cells including Xenopus oocytes and mammalian cell lines. These studies will reveal the binding of PIP2 and CaM to the channel protein and subsequent conformational changes that open the channel. These results will provide a molecular basis to understand how heart rhythm is regulated by cell signals and multiple mechanisms for drugs to target and modify, which may lead to the development of more effective and safe antiarrhythmic drugs.

项目摘要 本项目旨在揭示电压、磷脂酰肌醇4，5-二磷酸（PIP 2）和 钙调蛋白（CaM）整合激活心脏中的IKs钾离子通道。IKs通道很重要 用于心脏动作电位的复极和心律的控制。钙调素与膜脂PIP 2 是重要的细胞信号，同时这些分子是IKs通道的辅因子， 开放后这些使得IKs通道在心脏节律适应各种心律失常中发挥关键作用。 生理条件。先天性和药物诱导的IKs功能障碍与心律失常有关。 先前的研究和我们的初步数据表明，IKs通道是一个新的抗肿瘤治疗的目标。 本研究的意义在于提高对心脏电生理分子基础的认识 和抗疟疾药物的开发。 目前，CaM和PIP 2如何与IKs通道相互作用尚不清楚。这项提议的动机是， 最近发表的通道蛋白的结构数据。将这些数据与其他已发表和我们的 初步研究提出了一个令人兴奋的假说，即CaM、PIP 2和电压如何整合激活IKs 渠道我们的具体目标是研究这一假设的三个关键方面。我们将使用 电生理学方法，荧光光谱，结构信息诱变和分子 动态模拟研究在包括非洲爪蟾在内的外源表达细胞中表达的IKs通道 卵母细胞和哺乳动物细胞系。这些研究将揭示PIP 2和CaM与通道蛋白的结合 以及随后打开通道的构象变化。这些结果将提供分子基础， 了解心律是如何通过细胞信号和药物靶向和修饰的多种机制来调节的， 这可能会导致开发出更有效、更安全的抗心律失常药物。