Nedd4-dependent regulation of EnaC in hypertension

上皮Na+通道（ENaC）是肾素-血管紧张素-醛固酮途径的远端靶点，在血压控制中发挥重要作用。ENaC的功能获得性突变导致Liddle综合征，一种遗传性高血压。相反，功能丧失突变会导致盐耗和低血压的遗传性疾病（1型假性醛固酮减少症）。因此，了解这一通道的功能和调节将提供重要的见解，人类血压的变化和高血压的发病机制。在这个项目中，我们响应RFA的目标2;“遗传变异后果的机制研究。“在初步研究中，我们发现ENaC与泛素蛋白连接酶Nedd 4的相互作用在控制Na+吸收方面起着重要作用。一些研究结果表明，泛素蛋白连接酶在控制Na+吸收中起着重要作用。一些研究结果表明，Nedd 4可能在控制血压中起着关键作用。首先，在初步研究中，我们发现Nedd 4通过靶向通道降解来降低ENaC Na+电流。首先，在初步研究中，我们发现Nedd 4通过靶向通道降解来降低ENaC Na+电流。其次，在Liddle综合征中，ENaC中与Ndd 4结合的序列（PY基序）缺失或突变。第三，我们发现Liddle综合征中betaENaC亚单位的突变阻止了Nedd 4抑制通道。因此，本提案的总体目标是了解Nedd 4抑制通道的分子机制。因此，本提案的总体目标是了解Nedd 4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Nedd 4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Nedd 4抑制ENaC的分子决定因素。具体目标1将集中于Nedd 4中的C2结构域在ENaC的Ca 2+依赖性抑制中的作用，以及Nedd 4中的WW结构域与ENaC的PY基序之间的物理相互作用。特异性目标2将补充目标1，确定ENaC中参与Nedd 4相互作用和抑制的序列。具体来说，我们将研究的PY图案，在利德尔综合征的目标的作用，并测试的假设，泛素化的ENaC是必需的Nedd 4介导的抑制。在具体目标3中，我们将研究在高血压人群中发现的ENaC自然遗传变异的功能后果。这可能为ENaC和Nedd 4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。

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.