Coupled Gating of L-type Calcium Channels in Heart

心脏 L 型钙通道的耦合门控

基本信息

批准号：
8827841
负责人：
Luis F Santana
金额：
$ 38.42万
依托单位：
UNIVERSITY OF WASHINGTON
依托单位国家：
美国
项目类别：
财政年份：
2007
资助国家：
美国
起止时间：
2007-04-20 至 2015-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8827841
关键词：
1,2-diacylglycerol A kinase anchoring protein Action Potentials Address Adrenergic Agents Amino Acid Substitution Arrhythmia Autistic Disorder Calcineurin Calmodulin Cells Cellular Membrane Coupled Coupling Cyclic AMP Cyclic AMP-Dependent Protein Kinases Data Development Diglycerides Disease Electrophysiology (science)Event Frequencies Funding Gene Expression Genetic Transcription Goals Health Heart Heart failure Human Image Individual Knock-in Mouse Knockout Mice L-Type Calcium Channels Label Lead Light Location Long QT Syndrome Membrane Methods Modality Modeling Modification Molecular Biology Mus Muscle Cells Optics Phosphorylation Site Phosphotransferases Physiological Play Population Probability Public Health Research Resolution Role Sarcolemma Scaffolding Protein Shapes Signal Transduction Surface System Techniques Testing Timothy syndrome Total Internal Reflection Fluorescent Transgenic Mice Transgenic Organisms Translating Ventricular Wild Type Mouse Work adrenergic calcineurin phosphatase design heart function innovation interest mutant novel optogenetics patch clamp red fluorescent protein research study response transcription factor transcription factor NF-AT c3 treatment strategy

项目摘要

DESCRIPTION (provided by applicant): The work proposed in this application will test the hypothesis that L-type Cav1.2 channel activity varies along the sarcolemma of ventricular myocytes due to signaling micro-domains created by a subpopulation of these channels interacting with the scaffolding protein AKAP150. Preliminary data suggest the novel concept that AKAP150-associated Cav1.2 channels play a critical role in shaping action potential waveform, arrhythmogenesis, excitation-contraction (EC) coupling, and excitation-transcription (ET) coupling in ventricular myocytes. A key discovery is that small clusters of AKAP150-associated Cav1.2 channels are capable of undergoing coordinated openings and closings ("coupled gating"). The frequency of coupled gating events increases in cells expressing a mutant Cav1.2 channel that causes arrhythmias and autism in humans with long QT syndrome 8 (LQT8). The project has three specific aims designed to investigate the physiological and pathophysiological implications of these findings. Specific aim 1 is to test the hypothesis that AKAP150 is required for coupled gating of wild type (WT) and Cav1.2-LQT8 channels. Specific aim 2 is to test the hypothesis that coupled gating of WT and Cav1.2-LQT8 channels modulates EC coupling in ventricular myocytes. Finally, Specific aim 3 is to test the hypothesis that loss of AKAP150 protects against arrhythmias in WT and LQT8 mice. The methods that will be used to achieve these aims include patch-clamp electrophysiology, optical clamping, light- and chemically-induced dynamic targeting of kinases to cellular membranes, light-induced activation of adrenergic signaling (i.e., optogenetics), confocal, and TIRF microscopy. Experiments will involve a transgenic mouse specially created for this project and that expresses fluorescently labeled Cav1.2-LQT8 channels in ventricular myocytes as well as other transgenic, knock in, and knock out mice created by collaborators. This work will generate fundamental information on the mechanisms by which AKAP150 and Cav1.2 channels control of excitability, gene expression, and EC coupling in the heart under physiological and pathological conditions.