Function and structure of pendrin in thyroid cells

Pendrin在甲状腺细胞中的功能和结构

• 批准号: 6559922
• 负责人: PETER Andreas KOPP
• 金额: $ 26.05万
• 依托单位: NORTHWESTERN UNIVERSITY AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-01-01 至 2007-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6559922
• 关键词: MDCK cell; SDS polyacrylamide gel electrophoresis; anions; apical membrane; confocal scanning microscopy; gel mobility shift assay; hormone regulation /control mechanism; immunofluorescence technique; immunoprecipitation; iodine; ion transport; kidney function; membrane structure; membrane transport proteins; phosphorylation; protein localization; protein structure function; site directed mutagenesis; syndrome; thyroid function; tissue /cell culture; western blottings

DESCRIPTION (provided by applicant): Pendred's syndrome is an autosomal recessive disorder defined by congenital deafness, goiter and an impaired thyroidal iodide organification. It is caused by mutations in the PDS (Pendred's syndrome) gene. Mutations in this gene may be among the most frequent genetic causes of congenital deafness since they are not only associated with Pendred's syndrome, but they also form the molecular basis of two forms of non-syndromic deafness. The PDS gene encodes pendrin, an anion transporter belonging to the Solute Carrier Family 26A (SCL26A4). Pendrin is predominantly expressed in the thyroid, the kidney and the inner ear. Functional studies in Xenopus oocytes revealed that pendrin is able to transport chloride and iodide. In thyroid follicular cells, pendrin is expressed at the apical membrane suggesting that it could be involved in the transport of iodide into the follicular lumen. In the kidney, pendrin is found in beta-intercalated cells of the cortical collecting duct and is thought to function as a chloride/base exchanger. The exact role of pendrin in the inner ear remains unknown. Our preliminary data support the concept that pendrin is an apical iodide transporter. A detailed characterization of the anion transport properties of pendrin is essential for the understanding of its role in iodide transport in thyrocytes and the synthesis of thyroid hormones. At this point, there are no data on the kinetic properties of pendrin-mediated iodide transport, and its regulation. The membrane topology and secondary modifications of pendrin are unknown, and the determinants for PDS gene expression have not been characterized. The goals of this proposal are focused on studies addressing the function and structure of pendrin. The studies in Specific Aim 1 aim at further characterizing the iodide transport properties of pendrin. The experiments outlined in Specific Aim 2 seek to characterize the membrane topology and secondary modifications of pendrin and will thus contribute to the elucidation of structure-function relationships. The experiments in Specific Aim 3 will determine the cell specificity of the pendrin promoter and study its regulation. These studies will provide fundamental insights into the (patho) physiology of this novel anion transporter that has important functions in the thyroid, the kidney and the inner ear.

描述（由申请人提供）：彭德雷德综合征是一种常染色体隐性疾病，其定义为先天性耳聋、甲状腺肿和甲状腺碘有机化受损。它是由PDS（Pendred综合征）基因突变引起的。该基因的突变可能是先天性耳聋最常见的遗传原因之一，因为它们不仅与Pendred综合征有关，而且还形成了两种形式的非综合征性耳聋的分子基础。PDS基因编码pendrin，一种属于溶质载体家族26 A（SCL 26 A4）的阴离子转运蛋白。Pendrin主要在甲状腺、肾脏和内耳中表达。在非洲爪蟾卵母细胞的功能研究表明，pendrin是能够运输氯离子和碘离子。在甲状腺滤泡细胞中，pendrin在顶膜表达，表明其可能参与碘转运到滤泡腔中。在肾脏中，pendrin存在于皮质集合管的β-闰细胞中，被认为是氯/碱交换剂。pendrin在内耳中的确切作用仍然未知。我们的初步数据支持的概念，pendrin是一个顶端碘转运。pendrin的阴离子转运特性的详细表征是必不可少的了解其在甲状腺细胞中的碘离子转运和甲状腺激素的合成的作用。在这一点上，有没有pendrin介导的碘离子转运的动力学特性的数据，及其调节。pendrin的膜拓扑结构和二级修饰尚不清楚，PDS基因表达的决定因素尚未确定。该提案的目标是侧重于研究pendrin的功能和结构。具体目标1中的研究旨在进一步表征pendrin的碘化物转运特性。具体目标2中概述的实验旨在表征pendrin的膜拓扑结构和二级修饰，从而有助于阐明结构-功能关系。具体目标3中的实验将确定pendrin启动子的细胞特异性并研究其调控。这些研究将为这种在甲状腺、肾脏和内耳中具有重要功能的新型阴离子转运蛋白的（病理）生理学提供基本见解。