FUNCTION AND REGULATION OF CGMP GATED RENAL K+ CHANNELS

简介(摘自申请者摘要)：肾为本 参与全身钾的长期调节的器官。 钾平衡紊乱常见于 高血压、充血性心力衰竭、肝硬变和肾硬变 功能障碍。低钾血症会导致严重的心血管疾病和 利尿剂治疗患者的死亡率。此外，异常 钾通道的调节可能在高血压的发病机制中起一定作用。 高血压。本实验室致力于肾脏钾的研究。 频道。这项工作有助于发现几个新的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)，它在肾脏、心脏、肌肉和血管中表达。 KCNA10a具有与一氧化氮类似的动力学性质 在肺动脉平滑肌细胞中检测到敏感性K通道。 现在提议的工作是原来提议的延伸。这个 调查小组最近成功地优化了KCNA10a电流 在非洲爪哇卵母细胞中的表达，现在能够研究其动力学 详细介绍了单通道电平的特性。然后他们将确定 如果它是异源多聚体蛋白，以及它的表达水平和/或 动力学性质受先前克隆的任何活的 亚单位。他们将调查cGMP对KCNA10a的调控并询问 CGMP是否通过与cGMP结合结构域和/或通过 蛋白质磷酸化。最后，一组高亲和力的多克隆 将开发针对KCNA10a蛋白的特异性抗体，以便 观察其组织分布和膜定位。 其目的是已经进行的研究和提议的研究 将提供对以下机制的洞察： 钾平衡是维持的，因此应该有直接的临床 申请。人们还希望，新分子的发现 结构将扩展现有的钾的生理框架 动态平衡，并将导致新的治疗药物的开发。

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.