MOLECULAR REGULATION--CARDIAC K+ATP CHANNELS IN ISCHEMIA

ATP敏感性钾通道（KATP）在细胞内起重要作用， 在心脏、胰腺、脑 血管平滑肌 特别是在心脏，KATP参与 缺血性心律失常和心肌保护。 调控 KATP很复杂。 本建议侧重于知识、技能和技术培训知识的两个方面 调节：细胞质酸中毒的影响和阴离子 磷脂，这两者在缺血中可能都是重要的。 这 主要研究者以前的工作推动了重点， 天然心脏KATP，最近可用的KATP克隆（共- 表达BIR/SUR 1和KATP/SUR 2），并通过结构假设 磷脂的影响，涉及胞质C-尾的KATP。 在第一个目标中，将详细描述克隆KATP的特征。 并与天然KATP进行比较。 在第二个目标中， 酸中毒的影响，与其他条件相结合， 缺血，将在来自急性分离的天然KATP中研究 心肌细胞 在第三个目的中，研究了阴离子磷脂对 天然和克隆的KATP和其他相关内向整流通道 功能将被研究。 第四个目标是调节KATP 通过天然磷脂及其调节酶（磷酸酶 和激酶）将使用新的磷脂激酶进行研究。 在 第五个目标，磷脂的“C-末端拴系”假说 将使用重组DNA技术测试效果，包括位点 定向诱变、缺失和嵌合体。 虽然动机 研究的目的是在分子水平上解释 缺血条件下的KATP，预期的结果可能有 对超家族的结构/功能的广泛影响 内向整流钾通道，也将有影响 除了心脏之外，还有许多组织的生理功能。

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.