Ubiquitin-Protein Ligase Regulation of ENaC

ENaC 的泛素蛋白连接酶调节

• 批准号: 7092177
• 负责人: Peter M Snyder
• 金额: $ 26.47万
• 依托单位: UNIVERSITY OF IOWA
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-07-15 至 2008-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7092177
• 关键词: Xenopus; Xenopus oocyte; biological signal transduction; blood pressure; calcium; cyclic AMP; electrolyte balance; epithelium; familial hypertension; genetic polymorphism; intermolecular interaction; laboratory mouse; laboratory rat; ligase; protein binding; protein structure function; renal tubular transport; second messengers; sodium channel; ubiquitin; vasopressins

DESCRIPTION (provided by applicant): The goal of this proposal is to understand the role of WW domain ubiquitin-protein ligases in the regulation of renal Na v absorption via the epithelial Na v channel, ENaC. ENaC forms the pathway for Na + absorption in the kidney collecting duct and other epithelia. Thus, this channel plays a critical role in Na+ homeostasis and blood pressure control. Mechanisms that control the expression of ENaC at the cell surface play an important role in the regulation of epithelial Na v absorption. A key sequence is the PY motif, located in the C-termini of ENaC subunits. Mutation or deletion of this sequence increases the number of ENaC channels at the cell surface, causing an inherited form of hypertension (Liddle's syndrome). PY motifs mediate protein interactions by binding to WW domains, implicating a critical role for WW domain proteins. Previous work found that a WW domain protein (Nedd4) decreased Na+ current by binding to ENaC and targeting the channel for degradation. However, the role of Nedd4 in the kidney collecting duct is unknown. Moreover, it is clear that Nedd4 is part of a large family of Nedd4-related proteins. This proposal will use a systematic approach to test the hypothesis that WW domain proteins regulate ENaC-mediated Na* absorption in the collecting duct. Specific Aim 1 will identify the WW domain proteins that regulate ENaC, based on their expression patterns, their binding to ENaC subunits, and their ability to inhibit ENaC in heterologous expression systems and epithelial model systems. Specific Aim 2 will extend these results to test the hypothesis that WW domain proteins are regulated by cellular messengers (vasopressin/cAMP and Ca2+). This work will provide novel insights in the mechanisms by which these signaling pathways regulate epithelial Na + transport. Specific Aim 3 will test the hypothesis that polymorphisms in ENaC and WW domain proteins disrupt binding and/or channel regulation. By studying the functional consequences of naturally occurring genetic variation, these studies have potential to provide important new insights into the pathogenesis of renal diseases, including hypertension.

描述（由申请人提供）：本提案的目的是了解WW结构域泛素-蛋白连接酶在通过上皮Na v通道ENaC调节肾Na v吸收中的作用。ENaC形成肾脏集合管和其他上皮细胞中Na +吸收的途径。因此，该通道在Na+稳态和血压控制中起关键作用。控制ENaC在细胞表面表达的机制在上皮Na v吸收的调节中起重要作用。一个关键序列是PY基序，位于ENaC亚基的C-末端。该序列的突变或缺失增加了细胞表面ENaC通道的数量，导致遗传性高血压（Liddle综合征）。PY基序通过与WW结构域结合来介导蛋白质相互作用，暗示了WW结构域蛋白的关键作用。先前的工作发现WW结构域蛋白（Nedd 4）通过结合ENaC并靶向通道降解来降低Na+电流。然而，Nedd 4在肾脏集合管中的作用尚不清楚。此外，很明显Nedd 4是Nedd 4相关蛋白大家族的一部分。该提案将使用系统的方法来测试WW结构域蛋白调节集合管中ENaC介导的Na* 吸收的假设。具体目标1将根据其表达模式、其与ENaC亚基的结合以及其在异源表达系统和上皮模型系统中抑制ENaC的能力来鉴定调节ENaC的WW结构域蛋白。具体目标2将扩展这些结果，以测试的假设，WW域蛋白质的细胞信使（加压素/cAMP和Ca 2+）的调节。这项工作将提供新的见解，这些信号通路调节上皮Na +转运的机制。具体目标3将检验ENaC和WW结构域蛋白的多态性破坏结合和/或通道调节的假设。通过研究自然发生的遗传变异的功能后果，这些研究有可能为肾脏疾病（包括高血压）的发病机制提供重要的新见解。