Gating Mechanisms of KCNQ1/IKS Channels

KCNQ1/IKS 通道的门控机制

• 批准号: 10294845
• 负责人: Jianmin Cui
• 金额: $ 62.71万
• 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/10294845
• 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(PIP2)和磷脂酰肌醇(PIP2)的作用机制。 钙调素(CaM)结合激活心脏中的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率的控制。CaM与膜脂PIP2 是重要的细胞信号，同时这些分子也是通道所需的IKS通道的辅因子 开场了。这些都使iks通道在心率适应不同的过程中发挥关键作用。 生理条件。先天性和药物性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认识 以及抗心律失常药物的开发。 目前，CaM和PIP2如何与IKS通道相互作用尚不清楚。这项提议的动机是 最近公布了该通道蛋白的结构数据。将这些数据与其他已发布和我们的 初步研究得出了一个令人兴奋的假说，即CaM、PIP2和电压是如何整合到一起激活IKs的 频道。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 电生理方法、荧光光谱、结构信息突变和分子 外源表达细胞表达IKS通道的动态模拟 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。这些结果将提供分子基础 了解细胞信号如何调节心率，以及药物靶向和修饰的多种机制， 这可能会导致更有效、更安全的抗心律失常药物的开发。