Molecular Components of A-type K+ Channels

A型K通道的分子成分

• 批准号: 6750081
• 负责人: Bernardo Rudy
• 金额: $ 40.14万
• 依托单位: NEW YORK UNIVERSITY SCHOOL OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-06-01 至 2008-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6750081
• 关键词: Xenopus oocyte; antisense nucleic acid; brain; electrophysiology; gene targeting; granule cell; immunocytochemistry; immunoprecipitation; in situ hybridization; laboratory mouse; membrane proteins; nerve /myelin protein; neuropharmacology; pore forming protein; potassium channel; protein localization; protein quantitation /detection; protein structure function; transfection

DESCRIPTION (provided by applicant): Fast transient A-type K+ currents (IA), such as the subthreshold-activating somato-dendritic A-type K+ currents in neurons (ISA) and the fast transient outward K+ current in cardiac ventricular myocytes (Ito) are essential for the proper functioning of the brain and the heart. During pathophysiological conditions (e.g. ischemia in the heart and during the occurrence of stroke in brain) abnormalities in these currents contribute to the abnormalities associated with these disease conditions. This project addresses the molecular nature of the ion channels responsible for the generation of these currents. It seeks to establish the molecular composition of these channels and to elucidate the physiological significance of the identified components. Progress has been made in elucidating the molecular composition of the channels mediating the ISA and the Ito, and two key components, Kv4 pore-forming subunits and KCHIP associated proteins, have been identified. However, the kinetics of ISA channels in many neurons is faster than that of channels composed of Kv4 and KCHIP proteins. Evidence has been recently obtained for the presence in brain mRNA of transcripts encoding a factor (termed KAF), probably a novel associated subunit, which accelerates the kinetics of Kv4 channels. Moreover, a novel Kv4 channel associated protein (DPPX) has been identified utilizing biochemical methods, and evidence that this protein is responsible for KAF activity has been obtained. The goal of this project is to test the hypothesis that DPPX is an important component of Kv4 channels in many neurons and contributes to the properties and diversity of native A-type K+ channels. Aim 1 will investigate the effects of DPPX on Kv4 channel function in heterologous expression systems. Aim 2 will investigate where and when DPPX proteins are expressed in brain and their relationship to the other known components of Kv4 channels utilizing in-situ hybridization and immunohistochemistry. Aim 3 will investigate more directly the physiological significance of DPPX proteins in neurons utilizing gene targeting and antisense technology.

描述（由申请人提供）：快速瞬态A型K+电流（IA），例如神经元（ISA）中的子阈值激活的Somato-dendritic-dendritic-dendritic a-type k+电流（ISA）和快速的瞬态瞬态K+在心脏心肌细胞（ITO）中的快速瞬态k+电流对于适当的功能至关重要。在病理生理条件下（例如，心脏缺血和脑部中风期间）这些潮流中的异常有助于与这些疾病疾病有关的异常。该项目解决了负责产生这些电流的离子通道的分子性质。它试图建立这些通道的分子组成，并阐明已鉴定成分的生理意义。在阐明了介导ISA和ITO的通道的分子组成方面取得了进展，并且已经鉴定出了两个关键成分KV4孔形成亚基和Kchip相关蛋白。然而，许多神经元中ISA通道的动力学比由KV4和KCHIP蛋白组成的通道的动力学快。最近已经获得了证据，证明了编码因子（称为KAF）的转录本中的存在，这可能是一个新型的相关亚基，该亚基加速了KV4通道的动力学。此外，已经通过生化方法鉴定出了一种新型的KV4通道相关蛋白（DPPX），并证明已经获得了该蛋白质负责KAF活性。该项目的目的是检验以下假设：DPPX是许多神经元中KV4通道的重要组成部分，并有助于天然A型K+通道的特性和多样性。 AIM 1将研究DPPX对异源表达系统中KV4通道功能的影响。 AIM 2将调查DPPX蛋白在大脑中表达的何时何地，以及它们使用原位杂交和免疫组织化学的KV4通道的其他已知组成部分的关系。 AIM 3将更直接地研究利用基因靶向和反义技术的神经元中DPPX蛋白的生理意义。