ATP-SENSITIVE POTASSIUM CHANNELS IN THE HEART

在心脏中，代谢状态的主要传感器是atp敏感钾通道（KATP），它将代谢状态与电兴奋性联系起来，因此可能是缺血的主要参与者。本项目旨在了解心脏中KATP通道代谢控制的分子基础，以及这些通道在缺血反应中的病理生理作用。以前已经表明，磺酰脲受体（SUR）异构体，特别是核苷酸结合折叠（NBFs）是组织特异性KATP功能的关键决定因素。也有研究表明，SUR1和SUR2A对KATP通道的调节存在差异，生理条件下，SUR1产生的活跃通道更多。建立了在心脏中过表达KATP通道亚基的新型转基因小鼠，包括过表达SUR1和SUR2A的小鼠。SUR1过表达仅引起猝死。为了扩展这些初步数据，我们提出了实验来解决以下问题：(1)nbf -核苷酸相互作用如何调节KATP通道？为了实现这一目标，已经开发了一系列新的工具，包括SUR1的荧光报告结构和一种新的特异性抗SUR1抗体。这些将用于一系列旨在解决问题的生化和重组蛋白水平方法的实验中。所提出的实验结果将为KATP通道功能的结构和机制基础以及不同SUR亚型在心功能中的作用提供详细的见解。

In the heart, a major sensor of the metabolic state, and hence a potentially major player in ischemia, is the ATP-sensitive potassium (KATP) channel, which links metabolic state to electrical excitability. This project seeks to understand the molecular basis for metabolic control of KATP channels in the heart, and the pathophysiological role of these channels in the response to ischemia. Previously it has been shown that sulfonylurea receptor (SUR) isoforms, and in particular the nucleotide binding folds (NBFs) are critical determinants of tissue-specific KATP function. It has also been shown that SUR1 and SUR2A differentially regulate KATP channels, with SUR1 generating more active channels under physiological conditions. Novel transgenic mice overexpressing KATP channels subunits in the heart were developed, including mice overexpressing SUR1 and SUR2A. Overexpression of SUR1 only caused sudden death. In order to extend these preliminary data experiments are proposed to address the following question: (1) How do NBF-nucleotide interactions regulate KATP channels? In order to achieve this aim, a series of novel tools have been developed, including fluorescent reporter constructs of SUR1 and a novel specific anti-SUR1 antibody. These will be used in a series of experiments aimed at a biochemical and recombinant protein level approach to the problem. The results of the proposed experiments will bring detailed insight to the structural and mechanistic basis of KATP channel function and the role of differential SUR isoforms in cardiac function.