EBP50 REGULATION OF PTH RECEPTOR IN BONE AND KIDNEY

EBP50 对骨和肾中 PTH 受体的调节

• 批准号: 7049700
• 负责人: Peter A Friedman
• 金额: $ 30.44万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-02-01 至 2011-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7049700
• 关键词: SDS polyacrylamide gel electrophoresis; calcium; confocal scanning microscopy; epithelium; gene mutation; genetically modified animals; hormone receptor; hormone regulation /control mechanism; ion transport; kidney cell; laboratory mouse; mitogen activated protein kinase; parathyroid hormones; phospholipase D; polymerase chain reaction; receptor sensitivity; renal tubular transport; renal tubule; tissue /cell culture; western blottings

DESCRIPTION (provided by applicant): The long-term goal of this project is to elucidate the cellular mechanisms of parathyroid hormone receptor (PTH1R) action. The PTH1R regulates extracellular calcium and phosphate homeostasis by its actions on kidney and bone. Like other G protein-coupled receptors, the PTH1R exhibits a cyclical process of activation, desensitization, internalization, and resensitization. Receptor desensitization provides a mechanism to protect cells against excessive stimulation, while resensitization guards cells against prolonged inactivity and hormone resistance. Unlike most other receptors, however, the PTH1R exhibits considerable cell- and tissue-specific differences in its activation. These differences cannot be ascribed to alternatively spliced receptor forms, receptor abundance, or G protein availability. Recent evidence suggests that the cytoplasmic adaptor protein ezrin-binding protein 50 kD (EBP50) may contribute to cell-specific PTH1R signaling and internalization. The central goal of the proposed studies is to examine the interaction and modulatory activity of EBP50 on all aspects of PTH1R cycling. Four specific aims are developed to test the unifying hypothesis that EBP50 regulates ligand-specific responses of the PTH1R. Aim 1 will characterize the effects of EBP50 on cell-specific PTH1R activation. Aim 2 will describe EBP50 effects on PTH1R desensitization. Aim 3 will identify structural determinants of EBP50 that are involved in PTH1R internalization. Aim 4 will determine the effects of EBP50 on PTH1R recycling. The planned studies employ an array of cell biological, biochemical, and molecular biological techniques that will be applied to specific kidney and bone cells that are the primary targets of PTH action. Preliminary data provide provisional support and establish the feasibility for much of the proposed work. The planned studies will yield novel and important information on the mechanism and role by which the PTH1R regulates extracellular calcium homeostasis. The results will provide greater understanding of the initiation and termination of PTH1R action. The outcomes may suggest additional pathophysiological mechanisms causing PTH resistance and lead to new treatment opportunities.

描述（由申请人提供）：该项目的长期目标是阐明甲状旁腺激素受体（PTH1R）动作的细胞机制。 PTH1R通过其对肾脏和骨骼的作用来调节细胞外钙和磷酸盐稳态。与其他G蛋白偶联受体一样，PTH1R也表现出周期性的激活，脱敏，内在化和敏化过程。受体脱敏提供了一种保护细胞免受过度刺激的机制，同时敏感性避免了细胞免受长时间的不活跃和激素耐药性。然而，与大多数其他受体不同，PTH1R在激活中表现出很大的细胞和组织特异性差异。这些差异不能归因于剪接的受体形式，受体丰度或G蛋白的可用性。最近的证据表明，细胞质衔接蛋白EZRIN结合蛋白50 KD（EBP50）可能有助于细胞特异性的PTH1R信号传导和内在化。拟议的研究的核心目标是检查EBP50对PTH1R循环各个方面的相互作用和调节活性。开发了四个具体目标，以检验EBP50调节PTH1R配体特异性反应的统一假设。 AIM 1将表征EBP50对细胞特异性PTH1R激活的影响。 AIM 2将描述EBP50对PTH1R脱敏化的影响。 AIM 3将确定与PTH1R内部化有关的EBP50的结构决定因素。 AIM 4将确定EBP50对PTH1R回收的影响。计划的研究采用了一系列细胞生物学，生化和分子生物学技术，这些技术将应用于特定的肾脏和骨细胞，这是PTH作用的主要靶标。初步数据提供了临时支持，并确定了许多拟议工作的可行性。计划的研究将产生有关PTH1R调节细胞外钙稳态的机制和作用的新颖和重要信息。结果将对PTH1R作用的启动和终止有更深入的了解。结果可能表明其他病理生理机制引起PTH耐药性并带来新的治疗机会。