Nedd4-dependent regulation of EnaC in hypertension

高血压中 EnaC 的 Nedd4 依赖性调节

• 批准号: 6843765
• 负责人: Peter M Snyder
• 金额: $ 16.32万
• 依托单位: UNIVERSITY OF IOWA
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-02-01 至 2006-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6843765
• 关键词: Xenopus oocyte; confocal scanning microscopy; familial hypertension; gene mutation; human genetic material tag; molecular pathology; protein protein interaction; protein sequence; protein structure function; renal tubular transport; renin angiotensin system; saluresis; sodium channel; tissue /cell culture; transfection; ubiquitin

The epithelial Na+ channel (ENaC) is a distal target of the renin- angiotensin-aldosterone pathway, where it is critically positioned to play an important role in blood pressure control. Gain-of-function mutations in ENaC cause Liddle's syndrome, an inherited form of hypertension. Conversely, loss-of-function mutations cause a genetic disorder of salt wasting and hypotension (pseudohypoaldosteronism type 1). Thus, an understanding of the function and regulation of this channel will provide important insights into human blood pressure variations and the pathogenesis of hypertension. In this project, we are responsive to Goal 2 of the RFA; "mechanistic studies on the consequence of genetic variation." In preliminary studies, we found that the interaction of ENaC with Nedd4, a ubiquitin protein-ligase, plays an important role in controlling Na+ absorption. Several findings suggest that a ubiquitin protein-ligase plays an important role in controlling Na+ absorption Several findings suggest that Nedd4 might play a critical role in the control of blood pressure. First, in preliminary studies we found that Nedd4 decreases ENaC Na+ current by targeting the channel for degradation. First, in preliminary studies we found that Nedd4 decreases ENaC Na+ current by targeting the channel for degradation. Second, the sequences in ENaC that bind to Ndd4 (PY motifs) are deleted or mutated in Liddle's syndromes. Third, we found that Liddle's syndrome mutations in the betaENaC subunit prevention Nedd4 from inhibiting the channel. Thus, the overall goal of this proposal is to understand the molecular mechanisms by which Nedd4 from inhibiting the channel. Thus, the overall goal of this proposal is to understand the molecular mechanisms by which Nedd4 inhibits ENaC, and to begin to define the role of this pathway in Liddle's syndrome and more common forms of hypertension. Thus, the overall goal of this proposal is to understand the molecular mechanisms by which Nedd4 inhibits ENaC, and to begin to define the role of this pathway in Liddle's syndrome and more common forms of hypertension. In the first two specific aims, we will investigate the molecular determinants for the inhibition of ENaC by Nedd4. Specific Aim 1 will focus on the role of a C2 domain in Nedd4 in the Ca2+- dependent inhibition of ENaC, and on the physical interaction between WW domains in Nedd4 and the PY motifs of ENaC. Specific Aim 2 will complement Aim 1, determining the sequences in ENaC that are involved in the interaction and inhibition by Nedd4. Specifically, we will examine the role of the PY motifs that are targeted in Liddle's syndrome, and test the hypothesis that ubiquitination of ENaC is required for Nedd4- mediated inhibition. In Specific Aim 3, we will examine the functional consequences of natural genetic variation in ENaC found in hypertensive populations. This may provide important new insight into the role of ENaC and Nedd4 in human blood pressure variation and the pathogenesis of hypertension.

上皮Na+通道（ENaC）是肾素-血管紧张素-醛固酮通路的远端靶标，在血压控制中发挥重要作用。ENaC的功能获得性突变导致利德尔综合征，这是一种遗传性高血压。相反，功能缺失突变会导致盐消耗和低血压的遗传疾病（1型假性醛固酮减少症）。因此，了解该通道的功能和调控将为人类血压变化和高血压的发病机制提供重要的见解。在这个项目中，我们响应RFA的目标2；“对遗传变异后果的机理研究。”在初步研究中，我们发现ENaC与Nedd4（一种泛素蛋白连接酶）的相互作用在控制Na+吸收中起重要作用。一些研究结果表明，一种泛素蛋白连接酶在控制Na+吸收中起重要作用。一些研究结果表明，Nedd4可能在控制血压中起关键作用。首先，在初步研究中，我们发现Nedd4通过靶向降解通道降低ENaC Na+电流。首先，在初步研究中，我们发现Nedd4通过靶向降解通道降低ENaC Na+电流。其次，ENaC中与Ndd4结合的序列（PY基序）在Liddle综合征中被删除或突变。第三，我们发现betaENaC亚基的Liddle's综合征突变阻止Nedd4抑制该通道。因此，本提案的总体目标是了解Nedd4抑制通道的分子机制。因此，本提案的总体目标是了解Nedd4抑制ENaC的分子机制，并开始确定该途径在Liddle综合征和更常见的高血压形式中的作用。因此，本提案的总体目标是了解Nedd4抑制ENaC的分子机制，并开始确定该途径在Liddle综合征和更常见的高血压形式中的作用。在前两个具体目标中，我们将研究Nedd4抑制ENaC的分子决定因素。特异性目标1将关注Nedd4中的C2结构域在ENaC Ca2+依赖性抑制中的作用，以及Nedd4中的WW结构域与ENaC的PY基序之间的物理相互作用。特异性Aim 2将补充Aim 1，确定ENaC中参与Nedd4相互作用和抑制的序列。具体来说，我们将研究在Liddle综合征中靶向的PY基序的作用，并验证ENaC泛素化是Nedd4介导的抑制所必需的假设。在具体目标3中，我们将研究高血压人群中ENaC自然遗传变异的功能后果。这可能为ENaC和Nedd4在人类血压变化和高血压发病机制中的作用提供重要的新见解。