G PROTEIN LINKED REGULATION OF INTEGRINS BY IAP (CD47)

IAP 对整合素的 G 蛋白相关调控 (CD47)

• 批准号: 6012726
• 负责人: JOHN F MCDONALD
• 金额: $ 3.67万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-12-31 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/6012726
• 关键词: CD antigens; G protein; Sf9 cell line; angiogenesis; biological signal transduction; cell adhesion; cell growth regulation; cell migration; cholesterol; genetic manipulation; glycoproteins; integrins; ligands; membrane proteins; mutant; protein protein interaction; protein structure function; receptor coupling; receptor expression; thrombospondins; transfection /expression vector; vascular endothelium

Integrins initiate signaling pathways that impact tissue organization, inflammation, blood clotting, oncogenesis and angiogenesis upon binding of extracellular matrix proteins, in the regulation of biological processes. In this proposal, the role of integrin-associated protein (IAP, CD47), a co-receptor in mediating integrin signaling, will be studied by manipulation of both the receptor apparatus and the ligand structure. The C- terminal cell-binding domain (CBD) of thrombospondin (TS) is a ligand of IAP, and peptides derived from the CBD stimulate integrin-dependent processes via heterotrimeric G proteins. To define the mechanism of G protein coupling to the integrin-IAP complex, 1) a model expression system will be established for integrins, IAP and G protein subunits to evaluate receptor function in cellular assays upon treatment with IAP agonists; 2) direct measurements of G protein coupling will be carried out in the transfected cells and correlated with functional assays to identify the role of each component in the signaling complex; and 3) expression and mutagenesis of TS and CBD will be carried out to identify the determinants for IAP activation. By correlating changes in the interactions of the receptor and G protein components with downstream or "read-out" cellular functions, these studies should begin to define the molecular basis for the role of IAP in integrin-regulated biological processes such as angiogenesis, tumorigenesis and wound healing.

整合素在与细胞外基质蛋白结合后，在生物过程的调节中启动信号通路，影响组织组织、炎症、凝血、肿瘤发生和血管生成。在该提案中，将通过操纵受体装置和配体结构来研究整合素相关蛋白（IAP，CD47）（一种介导整合素信号转导的共受体）的作用。血小板反应蛋白 (TS) 的 C 端细胞结合结构域 (CBD) 是 IAP 的配体，源自 CBD 的肽通过异三聚体 G 蛋白刺激整合素依赖性过程。为了确定G蛋白与整合素-IAP复合物偶联的机制，1）将建立整合素、IAP和G蛋白亚基的模型表达系统，以评估IAP激动剂处理后细胞测定中的受体功能； 2) 在转染细胞中直接测量G蛋白偶联，并与功能测定相关联，以确定信号复合物中每个成分的作用； 3) 将进行 TS 和 CBD 的表达和诱变，以确定 IAP 激活的决定因素。通过将受体和 G 蛋白成分相互作用的变化与下游或“读出”细胞功能联系起来，这些研究应该开始确定 IAP 在整合素调节的生物过程（如血管生成、肿瘤发生和伤口愈合）中的作用的分子基础。