IDENTIFICATION AND CHARACTERIZATION OF THE GLEPP1/RECEPTOR LIGAND

GLEPP1/受体配体的鉴定和表征

• 批准号: 6201859
• 负责人: ROGER Charles WIGGINS
• 金额: $ 14.5万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-08-01 至 2000-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6201859
• 关键词: cell line; chimeric proteins; crosslink; expression cloning; genetic library; glomerular filtration; guinea pigs; immunoelectron microscopy; in situ hybridization; intercellular connection; laboratory rabbit; laboratory rat; ligands; membrane proteins; molecular cloning; molecular pathology; nephrotic syndrome; posttranslational modifications; protein binding; protein sequence; protein tyrosine phosphatase; proteinuria; renal glomerulus; transfection; western blottings

Progression to ESRD of diabetic glomerulosclerosis and other sclerosing glomerular diseases (e.g. FSGS) is associated with a leak of protein through the glomerular filter (the Nephrotic Syndrome). A major cell responsible for maintaining the integrity of the glomerular filter is the podocyte, whose interdigitating foot processes about the glomerular basement membrane, and between which the glomerular filtrate is formed. With prior support from the Renal Center we have identified, cloned and sequenced two major proteins of importance for the function of the glomerular filter. These are a novel podocyte foot process receptor tyrosine phosphatase (called GLEPP1) and podocalyxin (the major negatively charged molecule of the foot process originally identified by Farquhar and colleagues which is responsible for keeping foot processes apart by charge repulsion). Recent analysis of the GLEPP1 receptor shows that antibodies to the GLEPP1 receptor-like PTPase cause the glomerulus to become more permeable to albumin (leaky), probably in part by inhibiting the PTPase function of the enzyme. Thus a direct and previous unknown mechanism of control of the glomerular filter has been identified. At the same time new information shows that in other cells PTPases regulate intercellular junctions that are analogous to the slit diaphragms (specialized intercellular junctions) that serve as filtration devices between the foot processes of the podocyte. In this application we propose (a) to identify the GLEPP1 ligand using a recombinant GLEPP1 extracellular domain construct and a mammalian cDNA expression cloning strategy, and (b) to test the hypothesis that interference with the GLEPP1-ligand interaction modulates glomerular filter permeability using an isolated glomerular permeability assay. The long term goal will be to develop pharmacologic agents which can modulate glomerular permeability through this mechanism.

糖尿病性肾小球硬化和其他硬化的ESRD进展 肾小球疾病（例如FSG）与蛋白质的泄漏有关 通过肾小球滤波器（肾病综合征）。主要单元 负责维持肾小球滤波器的完整性是 足细胞，其肾小球的脚部互动 地下膜，并在其中形成肾小球滤液之间。 在肾中心的事先支持下，我们已经确定，克隆和 测序了两种重要蛋白质对功能的重要性 肾小球滤波器。这些是一种新颖的足细胞脚步受体 在 最初由Farquhar确定的脚步分子和 同事负责通过收费使脚步分开 排斥）。 GLEPP1受体的最新分析表明抗体 到Glepp1受体样PTPase导致肾小球变得更加 可渗透白蛋白（漏水），可能部分是通过抑制PTPase 酶的功能。因此是一种直接和以前未知的机制 已经确定了肾小球滤波器的控制。同时新 信息表明，在其他细胞中，PTPases调节细胞间 类似于缝隙diaphragm的连接（专业） 细胞间连接），作为脚之间的过滤设备 足细胞的过程。在此应用程序中，我们建议（a）确定 使用重组GLEPP1细胞外域的GLEPP1配体 构造和哺乳动物cDNA表达克隆策略，以及（b） 测试干扰GLEPP1配体相互作用的假设 使用孤立的肾小球调节肾小球滤波器的渗透率 渗透性测定。长期目标是开发药理学 可以通过这种机制调节肾小球渗透性的药物。