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Modulation of KCNQ1 channel activity

KCNQ1 通道活性的调节

基本信息

批准号：
10330452
负责人：
ROBERT S KASS
金额：
$ 40.83万
依托单位：
UNIVERSITY OF MIAMI SCHOOL OF MEDICINE
依托单位国家：
美国
项目类别：
财政年份：
2014
资助国家：
美国
起止时间：
2014-05-01 至 2023-12-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10330452
关键词：
A kinase anchoring protein AKAP9 gene Action Potentials Adaptor Signaling Protein Adenylate Cyclase Affect Area Arrhythmia Basic Science Binding Cardiac Cardiac Myocytes Clinical Complex Coupling Cryoelectron Microscopy Cyclic AMP-Dependent Protein Kinases Dependence Disease Dissection Ensure Familial atrial fibrillation Fluorometry Heart Heart Rate Human Induced Mutation Ion Channel Kinetics Life Link Long QT Syndrome Macromolecular Complexes Maps Membrane Potentials Molecular Molecular Chaperones Molecular Conformation Mutation Nerve PDE4D3 phosphodiesterase Pathologic Phosphatidylinositol 4,5-Diphosphate Phosphorylation Physiological Physiology Potassium Potassium Channel Protein phosphatase Proteins Regulation Role Short QT syndrome Signal Transduction Signaling Molecule Structure Sudden Death Syndrome Testing Time Translating Variant Ventricular Work beta-adrenergic receptor drug development experimental study mutant nanobodies novel public health relevance response voltage voltage clamp

项目摘要

Modified Project Summary/Abstract Section I{KS}, the slowly activating delayed rectifier potassium (K[+]) current in the heart is critical importance to human physiology as evident from the fact that mutations in either its α (KCNQ1) or β (KCNE1) subunit have been linked to multiple cardiac arrhythmia syndromes, including long QT syndrome (LQTS); short QT syndrome; and familial atrial fibrillation. The I{KS} channel is upregulated during sympathetic stimulation by PKA phosphorylation, which contributes critically to the physiological shortening of cardiac action potentials in response to sympathetic nerve activity. This shortening is necessary to ensure adequate ventricular filling time with accompanying increases in heart rate. It is also during sympathetic stimulation that most sudden deaths from LQTS occur. Understanding the mechanisms that underlie these mutation-induced arrhythmia syndromes requires unraveling the molecular interactions between KCNQ1 and KCNE1 within the context of normal and disease altered I{KS} channels. But to date, the critical questions of how KCNE1 alters KCNQ1 channel gating and how I{KS} channels are modulated by PKA are still not fully answered. Our previous work has revealed that Beta-AR regulation of channels requires assembly of a macromolecular complex that includes both KCNQ1 and KCNE1, as well as the adaptor protein Yotiao (AKAP 9). We will here use novel nanobodies to deliver regulatory domains of PKA directly to the KCNQ1/KCNE1 channel with and without co-assembly with AKAP9. These experiments will allow dissection of the critical role of AKAP9 in the delivery of signaling molecules to KCNQ1/KCNE1 from additional putative modulatory roles of the AKAP in modulating channel function post phosphorylation. In the recent CryoEM structure of KCNQ1 putative interacting residues between KCNQ1 and KCNE1 map between the VSD and PD, suggesting that KCNE1 is located in this area of the KCNQ1 structure. We will test whether KCNQ1 and KCNQ1/KCNE1 channels open using different gating hinges in S6. We will here also identify KCNQ1-KCNE1 interacting residues and determine whether these residues affect the different gating hinges. PKA has been shown to alter the voltage dependence, sub-conductance occupancy, and kinetics of I{KS} channels. Using voltage clamp fluorometry together with mutations and PIP2 depletion that uncouple the VSD and PD, we will determine whether PKA affect the VSD, PD, and/or VSD-to-PD coupling in I{KS} channels. The anticipated results of these experiments will provide a structural basis for control by PKA and KCNE1 of the physiological function of this critical ion channel and will also provide novel targets for the development of drugs to modulate its activity. This would be a milestone toward mutation-specific treatments of diseases, such as cardiac arrhythmias, caused by mutations in KCNQ1 and KCNE1.

修改项目摘要/摘要部分 I{KS}是心脏中缓慢激活的延迟整流钾（K[+]）电流，它对人体生理至关重要，这一点从其α（KCNQ 1）或β（KCNE 1）亚基的突变与多种心律失常综合征（包括长QT综合征（LQTS）、短QT综合征和家族性房颤）相关的事实中可以看出。I{KS}通道在交感神经刺激期间通过PKA磷酸化上调，这对响应交感神经活动的心脏动作电位的生理缩短起关键作用。这种缩短是必要的，以确保有足够的心室充盈时间，伴随着心率的增加。也正是在交感神经刺激期间，大多数LQTS猝死发生。了解这些突变诱导的心律失常综合征的机制，需要解开正常和疾病改变的I{KS}通道的背景下KCNQ 1和KCNE 1之间的分子相互作用。但迄今为止，KCNE 1如何改变KCNQ 1通道门控以及PKA如何调节I{KS}通道的关键问题仍未完全回答。我们之前的研究表明，通道的β-AR调节需要组装包括KCNQ 1和KCNE 1以及衔接蛋白Yotiao（AKAP 9）的大分子复合物。在这里，我们将使用新型纳米抗体将PKA的调节结构域直接递送到KCNQ 1/KCNE 1通道，与AKAP 9共组装或不共组装。这些实验将允许从AKAP在磷酸化后调节通道功能中的额外假定调节作用中剖析AKAP 9在将信号分子递送至KCNQ 1/KCNE 1中的关键作用。在最近的CryoEM结构的KCNQ 1之间的KCNQ 1和KCNE 1之间的相互作用的残基之间的VSD和PD的地图，这表明KCNE 1位于该地区的KCNQ 1结构。我们将在S6中测试KCNQ 1和KCNQ 1/KCNE 1通道是否使用不同的门控铰链打开。我们还将在这里确定KCNQ 1-KCNE 1相互作用的残基，并确定这些残基是否影响不同的门控铰链。PKA已被证明可以改变I{KS}通道的电压依赖性、亚电导占有率和动力学。使用电压钳荧光测定法以及使VSD和PD解偶联的突变和PIP 2耗尽，我们将确定PKA是否影响I{KS}通道中的VSD、PD和/或VSD至PD偶联。这些实验的预期结果将为PKA和KCNE 1控制这一关键离子通道的生理功能提供结构基础，也将为开发调节其活性的药物提供新的靶点。这将是针对KCNQ 1和KCNE 1突变引起的疾病（如心律失常）的突变特异性治疗的里程碑。

项目成果

期刊论文数量（22）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Cardiac Delayed Rectifier Potassium Channels in Health and Disease.

DOI：
10.1016/j.ccep.2016.01.004
发表时间：
2016-06
期刊：
Cardiac electrophysiology clinics
影响因子：
0
作者：
Chen L;Sampson KJ;Kass RS
通讯作者：
Kass RS

Pharmacological rescue of specific long QT variants of KCNQ1/KCNE1 channels.

DOI：
10.3389/fphys.2022.902224
发表时间：
2022
期刊：
FRONTIERS IN PHYSIOLOGY
影响因子：
4
作者：
Zou, Xinle;Wu, Xiaoan;Sampson, Kevin J.;Colecraft, Henry M.;Larsson, H. Peter;Kass, Robert S.
通讯作者：
Kass, Robert S.

Using fluorescence to understand β subunit-NaV channel interactions.

使用荧光来了解 β 亚基-NaV 通道相互作用。