WNK1 regulation of renal NaCl cotransport

WNK1 对肾脏 NaCl 共转运的调节

• 批准号: 7125600
• 负责人: AROHAN R SUBRAMANYA
• 金额: $ 5.75万
• 依托单位: UNIVERSITY OF MARYLAND BALTIMORE
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-09-01 至 2007-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7125600
• 关键词: Xenopus oocyte; chemical structure function; enzyme activity; enzyme induction /repression; enzyme mechanism; gene expression; genetic regulatory element; hypertension; immunoprecipitation; introns; membrane transport proteins; nucleic acid structure; postdoctoral investigator; protein protein interaction; renal tubular transport; serine threonine protein kinase; sodium chloride; tissue /cell culture

DESCRIPTION (provided by applicant): Familial Hyperkalemic Hypertension (FHHt, also known as Type II Pseudohypoaldosteronism or Gordon's syndrome) is a disorder of elevated blood pressure and potassium levels, and is phenotypically the "mirror image" of Gitelman's syndrome. FHHt is caused by mutations in the serine-threonine kinases WNK1 and WNK4, proteins highly expressed in the renal distal convoluted tubule (DCT). The sponsor has shown previously that WNK1 and WNK4 interact to regulate the thiazide-sensitive NaCI cotransporter (NCC). This proposal focuses on WNK1, whose transcription is upregulated in patients with FHHt due to a deletion within intron 1 of the WNK1 gene. WNK1 undergoes tissue-specific splicing, and the predominant renal isoform (kWNK1), contains a fractured kinase domain which is probably defective. Preliminary data suggest that kWNK1 may exert a dominant-negative effect on NCC cotransport by inhibiting the regulatory effect of WNK1. The experiments proposed herein serve to clarify the functional role of WNK1 and kWNK1 in the DCT. To this end, we will study the functional effects of kWNK1 on NCC cotransport in a Xenopus oocyte expression system. We will test for kWNK1 interactions with WNK1 with immunoprecipitation studies and in vitro kinase assays. We also propose a series of experiments that serve to identify cis elements within the first intron of the WNK1 gene that may be ablated in FHHt, leading to the upregulation of full length WNK1 relative to kWNK1.

描述（由申请人提供）：家族性高钾血症高血压（FHHt，也称为II型假性醛固酮增多症或戈登综合征）是一种血压和钾水平升高的疾病，在表型上是Gitelman综合征的“镜像”。FHHt是由丝氨酸-苏氨酸激酶WNK1和WNK4突变引起的，这两种蛋白在肾远曲小管（DCT）中高度表达。先前的研究表明，WNK1和WNK4相互作用调节噻嗪类药物敏感的NaCI共转运体（NCC）。本研究的重点是WNK1，由于WNK1基因内含子1的缺失，其转录在FHHt患者中上调。WNK1经历组织特异性剪接，主要的肾亚型（kWNK1）包含一个断裂的激酶结构域，这可能是有缺陷的。初步数据表明，kWNK1可能通过抑制WNK1的调控作用，对NCC共转运发挥显性负向作用。本文提出的实验旨在阐明WNK1和kWNK1在DCT中的功能作用。为此，我们将研究kWNK1在爪蟾卵母细胞表达系统中对NCC共转运的功能影响。我们将通过免疫沉淀研究和体外激酶测定来检测kWNK1与WNK1的相互作用。我们还提出了一系列实验，用于鉴定WNK1基因第一个内含子内的顺式元件，这些元件可能在FHHt中被吞噬，从而导致全长WNK1相对于kWNK1的上调。