FUNCTION AND REGULATION OF CGMP GATED RENAL K+ CHANNELS

描述（改编自申请人的摘要）：肾脏是主要的 参与全身钾的长期调节的器官。 钾平衡紊乱经常发生在有以下症状的患者中： 高血压、充血性心力衰竭、肝硬化和肾硬化 功能障碍 低钾血症导致显著的心血管发病率， 利尿剂治疗患者的死亡率。 此外，异常 K通道的调节可能在 高血压 本实验室主要研究肾钾 渠道 这项工作有助于发现几种新的K通道 基因. 其中一个基因编码cGMP激活的K选择性通道 (KCNA 10a），其在肾脏、心脏、肌肉和血管中表达。 KCNA 10a具有与一氧化氮类似的动力学性质 肺动脉平滑肌细胞中检测到敏感的K通道。 现在建议的工作是原来建议的延伸。 的 调查小组最近成功地优化了KCNA 10a电流 在非洲爪蟾卵母细胞中表达，现在能够研究其动力学 详细介绍了单通道级别的属性。 然后他们会决定 如果它是异源多聚体蛋白，并且如果它的表达水平和/或 动力学性质由任何先前克隆的活的 亚单位。 他们将研究cGMP对KCNA 10a的调节，并询问 cGMP是否通过与cGMP结合结构域结合和/或通过 蛋白质磷酸化 最后，一组高亲和力多克隆抗体， 将开发KCNA 10a蛋白的特异性抗体， 检查其组织分布和膜定位。 其目的是，已经进行的研究和拟议的研究 在当前的应用中，将提供对机制的洞察， 维持钾平衡，因此，应具有直接的临床意义。 应用. 人们也希望发现新的分子 结构将扩展钾的现有生理框架 这将导致新的治疗剂的开发。

DESCRIPTION (Adapted from the Applicant's Abstract): The kidney is the main organ involved in the long term regulation of total body potassium. Disorders of potassium balance occur frequently in patients who have hypertension, congestive heart failure, cirrhosis of the liver and renal dysfunction. Hypokalemia causes significant cardiovascular morbidity and mortality in patients treated with diuretics. Furthermore, abnormal regulation of K channels may play a role in the pathogenesis of hypertension. This laboratory is focused on the study of renal potassium channels. This work has let to the discovery of several novel K channel genes. One of these genes encode a cGMP-activated, K-selective channel (KCNA 10a) which is expressed in kidney, heart, muscle and blood vessels. KCNA10a has kinetic properties similar to those of the nitric oxide sensitive K channels detected in pulmonary artery smooth muscle cells. The work now proposed is an extension of the original proposal. The investigative team has recently succeeded in optimizing KCNA10a current expression in Xenopus oocytes and are now able to study its kinetic properties of the single channel level in detail. They will then determine if it is a hetero-multimeric protein and if its expression levels and/or kinetic properties are modulated by any of the live previously cloned a subunits. They will investigate the regulation of KCNA10a by cGMP and ask whether cGMP activates by binding to the cGMP-binding domain and/or via protein phosphorylation. Finally, a panel of high affinity polyclonal antibodies specific for the KCNA10a protein will be developed in order to examine its tissue distribution and membrane localization. The intent is that studies already carried out and those that are proposed in the current application will provide insight into the mechanisms by which K balance is maintained and should, therefore, have direct clinical applications. It is also hoped that the discovery of new molecular structures will expand the existing physiological framework of potassium homeostasis and will lead to the development of new therapeutic agents.