Gating Mechanisms of KCNQ1/IKS Channels

KCNQ1/IKS 通道的门控机制

• 批准号: 10686065
• 负责人: Jianmin Cui
• 金额: $ 61.92万
• 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/10686065
• 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; Signal Transduction; Site; Structure; Surface; Testing; Xenopus oocyte; cofactor; design; drug development; experimental study; fluorophore; heart rhythm; improved; molecular dynamics; novel; prevent; sensor; 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.

项目概要 该项目旨在揭示电压、磷脂酰肌醇4,5-二磷酸（PIP2）和 钙调蛋白 (CaM) 整合以激活心脏中的 IK 钾离子通道。 IKs通道很重要 用于心脏动作电位的复极化和心律的控制。 CaM 和膜脂 PIP2 是重要的细胞信号，同时这些分子是IKs通道所需的辅助因子 开放。这些使得 IKs 通道在心律适应各种变化中发挥关键作用。 生理条件。先天性和药物引起的 IK 功能障碍与心律失常有关。 之前的研究和我们的初步数据表明 IKs 通道是抗心律失常治疗的新靶点。 本研究的意义在于提高对心脏电生理学分子基础的理解 和抗心律失常药物的开发。 目前，CaM 和 PIP2 如何与 IK 通道相互作用尚不清楚。这项提议的动机是 最近发表了通道蛋白的结构数据。将这些数据与其他已发布的数据和我们的数据相结合 初步研究得出了关于 CaM、PIP2 和电压如何整合以激活 IK 的令人兴奋的假设 渠道。我们的具体目标旨在检验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 动态模拟研究外源表达细胞（包括非洲爪蟾）中表达的 IK 通道 卵母细胞和哺乳动物细胞系。这些研究将揭示 PIP2 和 CaM 与通道蛋白的结合 以及随后打开通道的构象变化。这些结果将为 了解细胞信号如何调节心律以及药物靶向和修改的多种机制， 这可能会导致更有效和更安全的抗心律失常药物的开发。