The Proteolytic Cleavage of Polycystin-1: How and Why

Polycystin-1 的蛋白水解裂解：如何以及为何

• 批准号: 7989311
• 负责人: Feng Qian
• 金额: $ 9.99万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-12-03 至 2010-12-02
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7989311
• 关键词: Affect; Age; Animal Model; Atomic Force Microscopy; Autosomal Dominant Polycystic Kidney; Biochemical; Biological; Biological Models; Cells; Cleaved cell; Cyst; Development; Disease; Distal; Duct (organ) structure; Embryonic Development; End stage renal failure; Extracellular Domain; G-Protein-Coupled Receptors; Grant; Human; In Vitro; Inborn Genetic Diseases; Kidney; Kidney Diseases; Lead; MDCK cell; Methods; Modeling; Mus; Mutation; Nephrons; PKD1 gene; Patients; Play; Property; Proteins; Reaction; Role; Site; Structure; System; Testing; Tissues; Tubular formation; United States; cell type; effective therapy; in vivo; insight; mouse model; novel; polycystic kidney disease 1 protein; postnatal; prevent; public health relevance; trafficking

DESCRIPTION (provided by applicant): Autosomal dominant polycystic kidney disease (ADPKD) is one of the most common inherited disorders in humans, affecting one in a thousand people in the United States. Patients develop multiple cysts in both kidneys. The cysts progressively result in the destruction of the normal kidney structure and eventually lead to end-stage renal failure in approximately 50% of the patients by the age of 60. There are currently no cures for the disease. ADPKD is caused primarily by mutations of the PKD1 gene, which encodes polycystin-1 (PC1) protein. Therefore understanding of the normal structure and function of PC1 will be critical for the development of effective therapies. We have previously discovered that PC1 is proteolytically cleaved at the G-protein coupled receptor proteolytic site (GPS) in virtually all cell types and tissues in vivo. This reaction, the GPS cleavage, generates a number of previously unrecognized PC1 products. Defective GPS cleavage of PC1 has been found in a subset of ADPKD patients. We hypothesized that GPS cleavage is essential for the complete function of PC1 in the kidney. We have recently demonstrated using a novel mouse model that GPS cleavage of PC1 is essential for proper structure and function of the distal nephron segments in the kidney, but is apparently not required for that of the proximal segments and for embryonic development. We now propose that the cleavage products of PC1 are critically required for the structural integrity of distal segments of the nephron in the kidney. This grant aims at understanding the mechanism by which GPS cleavage regulates the important function of PC1 in the kidney. We propose the studies in three complementary Specific Aims using a combination of biochemical, biophysical, cell-biological methods and animal models. Specific Aim 1 will analyze structure and function of PC1 products generated by GPS cleavage in an in vitro MDCK model system. This study will likely establish basic principles of GPS functioning. Specific Aim 2 then looks at the role of the PC1 cleavage products in primary cells and finally in mice. Specific Aim 3 examines the reason why the proximal segments do not require GPS cleavage. The proposed studies will likely yield important insights into the function of PC1 in normal and disease states of the kidney. PUBLIC HEALTH RELEVANCE Polycystin-1 is the protein that when defective causes a complicated kidney disease known as autosomal dominant polycystic kidney disease, which at this point has no cure. This study aims to understand Polycystin-1, the reasons it becomes defective, and the ways to prevent it.

描述(申请人提供)：常染色体显性遗传性多囊肾病(ADPKD)是人类最常见的遗传性疾病之一，在美国每千人中就有一人受到影响。患者在两个肾脏都会出现多个囊性病变。这些囊肿会逐渐导致正常肾脏结构的破坏，并最终导致约50%的患者在60岁之前发生终末期肾功能衰竭。目前还没有治愈这种疾病的方法。ADPKD主要由编码多囊蛋白-1(PC1)蛋白的PKD1基因突变引起。因此，了解PC1的正常结构和功能对于开发有效的治疗方法至关重要。我们先前已经发现，PC1在体内几乎所有类型的细胞和组织中都在G蛋白偶联受体蛋白水解点(GPS)处被蛋白水解性切割。这种反应，即GPS裂解，产生了许多以前未被识别的PC1产物。在部分ADPKD患者中发现了PC1的GPS裂解缺陷。我们推测，GPS裂解对于PC1在肾脏中的完整功能是必不可少的。我们最近用一个新的小鼠模型证明了PC1的GPS切割对于肾脏远端肾单位节段的正确结构和功能是必不可少的，但对近端肾单位节段和胚胎发育显然不是必需的。我们现在提出，PC1的切割产物对于肾脏中肾单位远端段的结构完整性是至关重要的。这项资助旨在了解GPS裂解调节PC1在肾脏中的重要功能的机制。我们建议使用生化、生物物理、细胞生物学方法和动物模型相结合的三个相辅相成的特定目标进行研究。具体目标1将在体外MDCK模型系统中分析GPS切割产生的PC1产物的结构和功能。这项研究可能会确立GPS功能的基本原则。特定目标2然后观察PC1裂解产物在原代细胞中的作用，最后是在小鼠身上。特殊目的3研究了为什么近端片段不需要GPS切割的原因。拟议的研究可能会对PC1在正常和疾病肾脏状态下的功能产生重要的见解。 公共卫生相关性 多囊蛋白-1是一种蛋白质，当缺陷时会导致一种复杂的肾脏疾病，称为常染色体显性多囊肾病，目前尚无治愈方法。本研究旨在了解Polycystin-1、其缺陷的原因以及预防方法。