STRUCTURE-FUNCTION OF MITOCHONDRIAL KIR

线粒体KATP通道（mitoKATP）是一种内膜蛋白，其功能是调节基质体积，从而保持膜间空间的结构。MitoKATP被认为是缺血性心脏保护的末端执行器。该项目的长期目标是了解mitoKATP的机制和调控，特别是与FIRCA项目相关的是，了解其亚基结构-功能。MitoKATP被假设由两个亚基组成，一个是K+通道（mitoKIR），一个是调节性磺酰脲受体（mitoSUR）。本项目利用我们在没有mitoSUR的情况下分离mitoKIR的能力，并研究其在脂质双层膜（BLM）中的电学性质。具体目的是阐明mitoKIR的电学性质；表征mitoKIR的调控并与完整的mitoKATP进行比较；并纯化足够的mitoKIR用于肽微测序。通道蛋白将通过一种新的乙醇/水提取方法从线粒体中分离出来，高度纯化的mitoKIR将被重组成BLM用于电生理研究，也用于微测序。

The mitochondrial KATP channel (mitoKATP) is an inner membrane protein whose function is to regulate matrix volume and, thereby, to preserve the architecture of the intermembrane space. MitoKATP has been postulated to be the end-effector of ischemic cardioprotection. The long-term goal of this project is to understand the mechanism and regulation of mitoKATP and, of particular relevance to this FIRCA project, to understand its subunit structure-function. MitoKATP is hypothesized to consist of two subunits, a K+ channel (mitoKIR) and a regulatory sulfonylurea receptor (mitoSUR). This project exploits our ability to isolate mitoKIR, without mitoSUR, and to study its electrical properties in lipid bilayer membranes (BLM). The specific aims are to elucidate the electrical properties of mitoKIR; to characterize regulation of mitoKIR and compare with the intact mitoKATP; and to purify sufficient mitoKIR for peptide microsequencing. The channel protein will be isolated from mitochondria by a novel ethanol/water extraction method, and the highly purified mitoKIR will be reconstituted into BLM for electrophysiological studies and also used for microsequencing.