MECHANISMS OF PERMEATION IN INWARD RECTIFIER K+ CHANNELS

描述 (摘自申请者的摘要)长期的职业目标是进行 独立研究，并在研究型大学任教。 目前，这是申请人作为助理教授的第一年 宾夕法尼亚大学生理学专业。她的长期目标是 研究是为了了解能力的结构和功能基础 在不同类型的细胞中完成其生物学任务的离子通道。 在这项提案中，她将研究离子在 内向整流钾通道。这些离子通道对 K+，并在向内比向外更有效地传递K+ 方向。后一种性质被称为内向整顿。这个 K+选择性和内向整流允许内向整流K+通道 调节许多细胞的静息膜电位，通过这一过程 完成它们的生物任务。这里提出的实验的目的是 就是研究这两个基本原理背后的分子机制 内向整流型钾离子通道的离子渗透特性。 克隆的内向整流性K+通道将在非洲爪哇卵母细胞和 将利用电生理学方法研究它们的渗透特性。 技巧。目的#1：研究人类免疫缺陷病毒的分子决定因素 选择性K+结合部位。申请者将使用一种综合方法： 在平衡条件下测量K+结合部位的占有率， 并诱变通道蛋白。目标2：调查 阿司匹林诱导细胞内阻断离子整流的机制 回答以下问题：a.阻断离子是否抑制外向K+ 通过占据一个K+结合部位而产生电流？B.外源性K+是否解除通道 通过静电机制被内部阻挡离子阻挡？ 拟议的研究具有重要的医学意义。例如, G蛋白门控内向整流钾通道介导心脏的调节 迷走神经和三磷酸腺苷敏感的内向整流钾通道 在心肌缺血期间很重要。(摘要结束)

DESCRIPTION (Adapted from applicants' abstract) The long term career goal is to conduct independent research and to teach in a research-oriented university. Currently, this is the applicant's first year as an Assistant Professor of Physiology at the University of Pennsylvania. The long term goal of her research is to understand the structural and functional basis of the ability of ion channels to accomplish their biological tasks in various cell types. In this proposal, she will investigate the mechanisms of ion permeation in inward-rectifier K+ channels. These ion channels are highly selective for K+, and pass K+ in the inward direction more efficiently than in the outward direction. This latter property has been termed inward rectification. The K+ selectivity and inward rectification allow inward-rectifier K+ channels to regulate the resting membrane potential in many cells, through which they accomplish their biological tasks. The aim of the experiments proposed here is to investigate the molecular mechanisms underlying these two fundamental properties of ion permeation in inward-rectifier K+ channels. Cloned inward-rectifier K+ channels will be expressed in Xenopus oocytes and their permeation properties will be studied using electrophysiological techniques. Aim #1: To investigate the molecular determinants of the selective K+-binding site. The applicant will use a combined approach: measuring the occupancy of K+-binding sites under equilibrium conditions, and mutagenizing the channel protein. Aim #2: To investigate the mechanisms of the rectification induced by intracellular blocking ions by addressing the following questions: a. Do blocking ions inhibit outward K+ current by occupying a K+-binding site? b. Does external K+ relieve channel blockade by internal blocking ions through an electrostatic mechanism? The proposed studies have important medical implications. For example, G-protein gated inward-rectifier K+ channels mediate the regulation of heart rate by vagal nerve, and ATP-sensitive inward-rectifier K+ channels are important during cardiac ischemia. (End of Abstract)