HCG-LH/CG Receptor Binding and Activation

HCG-LH/CG 受体结合和激活

• 批准号: 6613530
• 负责人: J DAVID PUETT
• 金额: $ 44.97万
• 依托单位: UNIVERSITY OF GEORGIA
• 依托单位国家: 美国
• 财政年份: 1983
• 资助国家: 美国
• 起止时间: 1983-09-01 至 2008-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6613530
• 关键词: G protein; biological signal transduction; chorionic gonadotropin; high performance liquid chromatography; hormone receptor; ion exchange chromatography; luteinizing hormone; nuclear magnetic resonance spectroscopy; protein binding; protein structure function; receptor binding; receptor coupling; receptor expression

DESCRIPTION (provided by applicant): The long-range goals of this project are delineation, at the molecular level, of: (a) the structural determinants responsible for specific, high-affinity binding of the heterodimeric glycoprotein hormone, human choriogonadotroin (hCG), to the lutropin/choriogonadotropin receptor (LHR), a member of the G protein-coupled receptor superfamily; (b) the mechanisms of ligand-dependent and ligand-independent LH receptor activation; and (c) the mechanism by which the receptor activates Gs to initiate intracellular signaling pathways. Several recent advances offer promise that elucidation of these fundamental issues in reproductive endocrinology are realistically achievable. Two specific aims, based upon emerging concepts of conformational plasticities of both the hormone and receptor, are proposed for this project. 1. Delineation of hCG and LHR binding determinants: This aim represents a continuation of ongoing studies to elucidate structures of and contact sites between wild type and engineered analogs of hCG and the receptor ectodomain, with a rigorous test of the proposed model of the ectodomain that is postulated to have a cusp shape due to a series of leucine-rich repeats. 2. Mechanisms of receptor activation and Gs coupling: This aim addresses the mechanisms by which wild type and engineered extracellular hCG-ectodomain complexes activate the transmembrane portion of the receptor, the resulting structural changes of the transmembrane helices and intracellular loops responsible for LHR activation, and elucidation of determinants in LHR required for Gs activation. A combination of protein engineering, biophysical investigations, and cell/molecular biological techniques will be utilized to address these aims. Success of this project will greatly enhance our understanding of fundamental mechanisms in male and female reproductive endocrinology and provide new information to assist rational design of LHR agonists and antagonists.

描述（申请人提供）：本项目的长期目标是在分子水平上阐明：（a）负责异源二聚体糖蛋白激素人绒毛膜促性腺激素（hCG）与促黄体激素/绒毛膜促性腺激素受体（LHR）（G蛋白偶联受体超家族成员）特异性高亲和力结合的结构决定因素;（B）配体依赖性和配体非依赖性LH受体激活的机制;和（c）受体激活Gs以启动细胞内信号传导途径的机制。最近的一些进展提供的承诺，阐明这些基本问题在生殖内分泌学是现实可行的。两个具体的目标，基于新兴的概念的构象可塑性的激素和受体，提出了这个项目。1. hCG和LHR结合决定簇的描述：该目标代表了正在进行的研究的继续，以阐明野生型和工程改造的hCG类似物与受体胞外域之间的结构和接触位点，并对所提出的胞外域模型进行了严格的测试，该模型被假定为由于一系列富含亮氨酸的重复序列而具有尖点形状。2.受体激活和Gs偶联的机制：本研究旨在探讨野生型和工程化细胞外hCG-胞外域复合物激活受体跨膜部分的机制，导致LHR激活的跨膜螺旋和胞内环的结构变化，以及阐明Gs激活所需的LHR决定簇。蛋白质工程，生物物理学研究和细胞/分子生物学技术的组合将被用来解决这些目标。该项目的成功将大大提高我们对男性和女性生殖内分泌学基本机制的理解，并为合理设计LHR激动剂和拮抗剂提供新的信息。