Regulations and function of the M-channel

M通道的规定和功能

基本信息

批准号：
8576472
负责人：
Naoto Hoshi
金额：
$ 32.47万
依托单位：
UNIVERSITY OF CALIFORNIA-IRVINE
依托单位国家：
美国
项目类别：
财政年份：
2010
资助国家：
美国
起止时间：
2010-01-15 至 2015-11-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8576472
关键词：
Acetylcholine Action Potentials Address Affinity Arousal Attention Binding Binding Sites Biochemical Biological Assay Brain Calcium Calmodulin Cell Culture Techniques Cell Line Cells Cognition Complex DNA Sequence Rearrangement Dissociation Epilepsy Fluorescence Resonance Energy Transfer Frequencies Genes Goals Health Image In Vitro Ion Channel Isaacs syndrome Learning Life Link Measurement Mediating Memory Microscopy Modeling Molecular Muscarinic Acetylcholine Receptor Muscarinics Mutation Myeloma Proteins Nerve Pain Neuronal Plasticity Neurons Neurotransmitters Pain Patch-Clamp Techniques Pathway interactions Phosphatidylinositol 4,5-Diphosphate Phospholipase C Phosphorylation Physiological Potassium Potassium Channel Process Receptor Activation Regulation Regulatory Pathway Reporting Role Scaffolding Protein Seizures Signal Transduction Testing Therapeutic Therapeutic Agents Work cholinergic cofactor design mutant nervous system disorder neuronal excitability protein complex research study voltage voltage gated channel

项目摘要

DESCRIPTION (provided by applicant): The M-type voltage-gated potassium current regulates action potential threshold and spike frequency adaptation. The M current is suppressed by various neurotransmitters including acetylcholine, which elicits hyperexcitable periods upon stimulation. To date, a number of mutations in the genes encoding the M channel, KCNQ2, 3, 4 and 5, have been reported to cause neurological disorders such as epilepsy and neuromyotonia. Accordingly, M channel modulators are considered potential therapeutic agents to control neuronal excitability in pathogenic conditions such as epilepsy, pain and cognition. The long-term goal of this project is to elucidate regulation and physiological relevance of the M current modulation as a model for understanding roles of low threshold voltage-gated channels in higher brain function. Several parallel regulatory pathways have been identified for mediating the neurotransmitter-induced suppression of the M channel, one of which is depletion of PIP2 by activation of phospholipase C. Accumulating evidence shows PIP2 is an essential cofactor for a wide variety of ion channels and transporters. This general requirement for PIP2 raises the question of how PIP2 deletion selectively regulates the M channel. The hypothesis addressed in this proposal is that the M channel reduces its affinity to PIP2 due to rearrangement of the macromolecular channel complex during the neurotransmitter-induced suppression. The specific aims are to: 1) link change in components of the M channel complex and reduction of PIP2 affinity during muscarinic cholinergic stimulation; 2) elucidate changes in the M channel complex induced by calcium and cross talks with other pathways. These aims will be tested by a combination of electrophysiological, biochemical and imaging approaches designed to address how the channel complex is arranged. Channel activity and conformational change will be recorded simultaneously using a patch clamp technique under FRET microscopy in transfected cultured cell lines and cultured neurons. This work will advance our understanding of how the M channel is regulated to control neuronal excitability.

描述（由申请人提供）：M型电压门控钾电流调节动作电位阈值和尖峰频率适应。 M电流受到包括乙酰胆碱在内的各种神经递质的抑制，这在刺激时会引起过度可观的时期。迄今为止，据报道，编码M通道KCNQ2、3、4和5的许多突变会引起神经系统疾病，例如癫痫和神经瘤。因此，M通道调节剂被认为是在致病条件（例如癫痫，疼痛和认知）中控制神经元兴奋性的潜在治疗剂。该项目的长期目标是阐明M当前调制的调节和生理相关性，作为了解低阈值电压门控通道在较高大脑功能中的作用的模型。已经确定了几种平行调节途径，用于介导神经递质引起的M通道的抑制，其中之一是通过激活磷脂酶C的耗尽。积累的证据表明，PIP2是PIP2是多种离子通道和转运蛋白的必不可少的辅助因子。对PIP2的一般要求提出了一个问题，即PIP2如何选择性地调节M通道。该提案中解决的假设是，由于神经递质引起的抑制过程中大分子通道复合物的重排，M通道降低了其与PIP2的亲和力。具体目的是：1）在毒蕈碱胆碱能刺激过程中，M通道复合物的组成部分的链接变化以及PIP2亲和力的降低； 2）阐明由钙和与其他途径交叉交谈引起的M通道复合物的变化。这些目标将通过电生理，生化和成像方法的结合来测试，旨在解决如何布置通道复合物。通道活性和构象变化将使用在转染的培养细胞系和培养的神经元中的FRET显微镜下同时记录。这项工作将促进我们对如何调节M通道来控制神经元兴奋性的理解。