MOLECULAR REGULATION--CARDIAC K+ATP CHANNELS IN ISCHEMIA

三磷酸腺苷敏感钾通道(KATP)起重要作用 在心脏、胰腺、脑、 血管平滑肌。特别是在内心，KATP参与了 缺血性心律失常与心肌保护。规管 KATP是复杂的。该提案侧重于KATP的两个方面 调节：细胞质酸化的影响和阴离子的影响 磷脂，这两种物质在缺血中都可能是重要的。这 重点关注的是首席调查员以前在以下方面的工作 天然心脏KATP，最近KATP克隆的可用性(co- 表达的BIR/SUR1和KATP/SUR2)，并通过结构假说 涉及KATP胞质C-尾的磷脂效应。 在第一个目标中，克隆KATP的详细特征将是 并与当地的KATP进行了比较。在第二个目标中， 酸中毒的影响，结合在 缺血，将从急性分离的天然KATP中进行研究 心肌细胞。在第三个目的中，阴离子磷脂对血管生成的影响 天然和克隆的KATP及其他相关的内向整流通道 功能将被调查。在第四个目标中，对KATP的监管 由天然磷脂及其调节酶(磷酸酶 和激酶)将使用一种新的磷脂激酶进行研究。在……里面 第五个目标，磷脂的“C-末端系留”假说 将使用包括SITE在内的重组DNA技术来测试效果 定向突变、缺失和嵌合体。虽然动机是 是为了在分子水平上解释 对KATP的缺血情况，预期的结果很可能会有 对超家族的结构/功能的广泛影响 内向整流钾通道，也将产生影响 除了心脏之外，还有许多组织的生理学。

The ATP-sensitive potassium channel (KATP) plays important physiological and pathophysiological roles in heart, pancreas, brain, vascular smooth muscle. Particularly in heart, KATP participates in ischemic arrhythmias and myocardial preservation. Regulation of KATP is complex. This proposal focuses on two aspects of KATP regulation: effects of cytoplasmic acidosis and effects of anionic phospholipids, both of which may be important in ischemia. This focus is motivated by previous work of the Principal Investigators on native cardiac KATP, by the recent availability of KATP clones (co- expressed BIR/SUR1 and KATP/SUR2), and by a structural hypothesis of phospholipid effects involving the cytoplasmic C-tail of the KATP. In the first aim, detailed characterization of clones KATPs will be performed and compared with native KATP. In the second aim, the effects of acidosis, in combination with other conditions found in ischemia, will be investigated in native KATP from acutely isolated cardiac cells. In the third aim, the effects of anionic phospholipids on native and cloned KATP and other related inward rectifier channel function will be investigated. In the fourth aim, regulation of KATP by native phospholipids and their regulatory enzymes (phosphatases and kinases) will be investigated using a novel phospholipid kinase. In the fifth aim, the 'C-terminus tethering' hypothesis for phospholipid effects will be tested using recombinant DNA technology including site directed mutagenesis, deletions, and chimera. Although the motivation for the studies is to account at the molecular level for effects of ischemic conditions on KATP, the expected results are likely to have wide implications for the structure/function of the superfamily of inward rectifier potassium channels, and will also have implications for the physiology of many tissues in addition to heart.