Role of Kir6.1 subunits of K+ channels in heart

描述（申请人的逐字描述）：ATP敏感（KATP） 通道将能量代谢和应激与膜兴奋性偶联， 在心中高度表达。它们在心脏和冠状血管中的功能 已经通过使用药理学试剂进行了广泛的研究， 阻断KATP通道。KATP通道亚基的分子克隆揭示了 KATP通道由成孔Kir 6亚基组成， 调节SUR亚单位。有两个Kir 6成员（Kir6.1和Kir6.2）， 在心中得到了高度的表达。心脏KATP通道被认为是由 Kir6.2/SUR 2复合物。然而，Kir6.1的作用是未知的。总目标 本申请的目的是检查Kir6.1亚基在肿瘤细胞中的功能。 心血管系统由于蛋白质的定位可以指示 它的功能，我们将研究区域，细胞和亚细胞 Kir6.1亚单位在心肌细胞中的分布模式，传导 系统，在冠状血管和内皮细胞中使用 免疫组织化学技术（我们已经开发出优秀的抗体， 这个目的）。我们表明，生物化学和电生理，Kir6.1和 Kir6.2亚基可以在异源表达系统中共组装，表明 这也可能发生在心脏。我们将研究这种联合组装是否 对天然Kir 6蛋白的作用。我们还将研究功能 使用膜片钳技术的异聚Kir 6通道的特性。我们 将产生Kir6.1基因靶向破坏的小鼠。LoxP研究中心将 在Kir6.1基因座中引入，这些小鼠将与其他小鼠杂交， 在心脏中过度表达Cre我们将直接利用这些老鼠 Kir6.1亚单位在心脏和血管功能中的作用 离体Langendorff灌注心脏技术。冠脉血流和 - 储备将与缺血期间的心脏功能一起沿着测量， 再灌注和缺血预处理。这些研究将提供一个 框架，以了解KATP通道的复杂性， 心血管系统，特别是Kir6.1亚基的作用，并将 提供了分子的见解，KATP通道在动物中的功能， 正常和病理生理条件。

DESCRIPTION (the applicant's description verbatim): ATP-sensitive (KATP) channels couple energy metabolism and stress to membrane excitability and are highly expressed in heart. Their function in the heart and coronary vasculature has been studied extensively by the use of pharmacological agents that open or block KATP channels. The molecular cloning of subunits of KATP channel revealed that KATP channels consist of pore-forming Kir6 subunits in association with regulatory SUR subunits. There are two Kir6 members (Kir6.1 and Kir6.2) - both are highly expressed in heart. Cardiac KATP channels are believed to consist of Kir6.2/SUR2 complexes. However, the role of Kir6.1 is unknown. The overall goal of this application is to examine the function of Kir6.1 subunits in the cardiovascular system. Since the localization of a protein can be indicative of its function, we will examine the regional, cellular and subcellular distribution patterns of Kir6.1 subunits in cardiac myocytes, the conduction system, in the coronary vasculature and in endothelial cells using immunohistochemistry techniques (we have developed excellent antibodies for this purpose). We show biochemically and electrophysiologically that Kir6.1 and Kir6.2 subunits can co-assemble in heterologous expression systems, suggesting that this may also occur in heart. We will examine whether such co-assembly takes place for native Kir6 proteins. We will also investigate the functional characteristics of heteromeric Kir6 channels using patch clamp techniques. We will generate mice with targeted disruption of the Kir6.1 gene. LoxP sites will be introduced in the Kir6.1 locus and these mice will be crossed with others overexpressing Cre in the heart. We will utilize these mice directly to examine the role of Kir6.1 subunits in the function of heart and vasculature using isolated, Langendorff-perfused heart techniques. Coronary blood flow and -reserve will be measured along with heart function during ischemia, reperfusion and ischemic preconditioning. These studies will provide a framework in which to understand the complexity of KATP channels in the cardiovascular system, in particular the role of Kir6.1 subunits, and will provide molecular insights into the function of KATP channels in animals during normal and pathophysiological conditions.