H,K,ATPASE FUNCTION IN POTASSIUM HOMEOSTASIS

H,K,ATP酶在钾稳态中的功能

• 批准号: 6637154
• 负责人: Charles S Wingo
• 金额: $ 23.68万
• 依托单位: UNIVERSITY OF FLORIDA
• 依托单位国家: 美国
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-08-01 至 2004-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6637154
• 关键词: adenosinetriphosphatase; basal metabolism; enzyme activity; enzyme structure; immunocytochemistry; in situ hybridization; isozymes; kidney function; laboratory mouse; laboratory rabbit; potassium channel; renal medulla; urine acidity

The long-range goal of this research is to examine the role of H,K-ATPases in potassium homeostasis and to determine how these ion-motive pumps are regulated by ion channels. H,K-ATPases are important for renal potassium conservation, but it is now apparent that the kidney possesses several different H,K-ATPase enzymatic activities which likely reflect the presence of multiple gene products. Experiments in Specific Aim 1 will determine the molecular identities of the H,K-ATPase subunit isoforms that are responsible for specific enzymatic activities, and for potassium and proton flux in discrete nephron segments, by the study of animals with targeted gene disruption of the H,K-ATPase HK-alpha-1, HK-alpha-2, or HK-beta genes. Experiments in Specific Aim 2 will examine whether knockout of HK-alpha-1, HK-alpha-2, or HK-beta subunits affects the normal anatomy of the kidney or the morphological response to potassium depletion. Experiments in Specific Aim 3 will characterize fully the newly discovered potassium-permeable ion channels that are present at the apical membrane of the inner stripe of the outer medullary collecting duct (OMCD), and the cell types that contain these channels. These channels exhibit novel properties since they appear to be stimulated by cellular acidification whereas most potassium channels are inhibited by acidosis. The proposed experiments are intended to establish the contribution of each of these genes to an important adaptive response (potassium depletion), the compensatory renal response to the disruption of these genes, and whether these genes are involved in the normal morphology of the kidney or its response to potassium depletion. Since accruing evidence indicates that modest potassium depletion causes or contributes to systemic arterial hypertension, and may contribute to chronic renal insufficiency, these studies area expected to contribute to our understanding of the role of potassium depletion as a risk factor for both renal and cardiovascular disease.

本研究的长期目标是检查 H,K-ATP 酶的作用 钾稳态并确定这些离子动力如何 泵由离子通道调节。 H,K-ATP酶对于肾功能很重要 钾的保存，但现在很明显肾脏拥有 几种不同的 H,K-ATPase 酶活性可能反映了 多种基因产物的存在。具体目标 1 中的实验将 确定 H,K-ATP 酶亚基亚型的分子身份 负责特定的酶活性以及钾和质子 通过对具有目标基因的动物进行研究，离散肾单位片段的通量 H,K-ATPase HK-alpha-1、HK-alpha-2 或 HK-beta 基因的破坏。 具体目标 2 中的实验将检验 HK-alpha-1 是否被敲除， HK-alpha-2 或 HK-beta 亚基影响肾脏或肾脏的正常解剖结构 对钾消耗的形态反应。具体目标 3 中的实验 将充分表征新发现的钾渗透离子通道 存在于外条纹内条纹的顶膜处 髓质集合管 (OMCD) 以及包含这些的细胞类型 渠道。这些通道表现出新颖的特性，因为它们似乎是 受细胞酸化刺激，而大多数钾通道 受酸中毒抑制。所提出的实验旨在建立 这些基因中的每一个对重要的适应性反应的贡献 （钾耗竭），肾脏对钾离子破坏的代偿反应 这些基因，以及这些基因是否参与正常形态 肾脏或其对钾缺乏的反应。自从收集了证据 表明适度的钾消耗会导致或促成全身性 动脉高血压，并可能导致慢性肾功能不全，这些 研究领域预计将有助于我们理解 钾缺乏是肾脏和心血管疾病的危险因素。