Mechanisms of Adhesion GPCR Action

粘附 GPCR 作用机制

基本信息

批准号：
9981283
负责人：
Gregory Gordon Tall
金额：
$ 36.66万
依托单位：
UNIVERSITY OF MICHIGAN AT ANN ARBOR
依托单位国家：
美国
项目类别：
财政年份：
2016
资助国家：
美国
起止时间：
2016-09-15 至 2024-01-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9981283
关键词：
ADGR1 gene Adherence Adhesions Adhesives Agonist Anabolism Animal Model Anticoagulants Binding Binding Sites Biochemical Biological Assay Blood Blood Coagulation Disorders Blood Platelets Blood Vessels Blood coagulation Blood flow Brain C-terminal Cell membrane Cells Coagulation Process Collagen Collagen Receptors Complex Data Defect Dependence Dissociation Engineering Event Exposure to Extracellular Matrix G-Protein-Coupled Receptors GTP-Binding Proteins Gold Hemorrhage Hemostatic function Human Immobilization In Vitro Injury Knockout Mice Knowledge Ligands Mass Spectrum Analysis Measures Mediating Modeling Molecular Mus Mutagenesis N-terminal Peptides Pharmacology Physiological Physiology Platelet Activation Proteolysis Receptor Activation Role Series Shapes Signal Transduction Signaling Protein Site Surface Testing Theoretical model Thrombosis Thrombus Tissues Transmembrane Domain Tube Ultraviolet Rays Whole Blood Work base cell motility crosslink experience experimental study extracellular follow-up high throughput screening in vitro activity in vivo member mimetics mouse model programs protease-activated receptor 4 protein reconstitution receptor response small molecule libraries tool vascular injury wound wound healing

项目摘要

Summary/Abstract: GPR56/ADGRG1 is a deorphanized brain Adhesion G protein Coupled Receptor (AGPCR) with a physiological ligand, collagen. We present new evidence that GPR56 is present on the surface of human and mouse platelets. This is very intriguing considering that autonomous platelet activation that leads to clot formation is mediated by platelet interactions with collagen that becomes exposed at sites of vessel injury. We found that pharmacological activation of platelet GPR56 is sufficient to elicit the physiological platelet activation program required for wound healing (hemostasis) and blood clotting (thrombosis). Moreover, Gpr56 knockout mice have a severe bleeding disorder and dramatic defects in clot formation in mouse vessel wall injury models. We hypothesize that GPR56 is the platelet collagen receptor that mediates the initial G protein 12/13-dependent platelet shape changes while platelets roll/translocate along exposed collagen to their site of stable adhesion at the lagging edges of blood vessel wounds. We will investigate platelet GPR56-mediated G protein signaling, platelet shape changes, in vitro platelet activation, and the role of GPR56 in mouse models of hemostasis and thrombosis. We found compelling preliminary evidence that platelets from Gpr56 knockout mice are dramatically defective in adhering to an immobilized collagen surface when mouse blood is flowed over the surface at high shear force. We propose that GPR56 is not directly involved in stable platelet adhesion, but as platelets tumble across the collagen surface, GPR56 is stimulated to cause the shape changes that allow platelets to then stably adhere via distinct non-GPCR collagen receptors. Before discovering GPR56 on platelets we proposed a general model of AGPCR activation that required anchoring of the receptor N-termini, and shear force-mediated receptor dissociation that leads to exposure of the AGPCR tethered agonists to induce G protein signaling. The conditions experienced by platelet-borne GPR56 align remarkably well with this theoretical model. Our work also includes conducting biochemical studies using newly developed photo-crosslinking agonist probes to define the agonist binding sites of the related AGPCRs, GPR56 and GPR114.

摘要/摘要：GPR56/ADGRG1是一种去畸形的脑粘附G蛋白耦合受体（AGPCR）带有生理配体，胶原蛋白。我们提供了新的证据，表明GPR56存在于人的表面和鼠标血小板。考虑到导致凝块的自主血小板激活，这是非常有趣的形成是通过与胶原蛋白相互作用在血管损伤部位暴露的。我们发现血小板GPR56的药理激活足以引起生理血小板激活伤口愈合（止血）和血液凝结（血栓形成）所需的程序。此外，GPR56淘汰赛小鼠在小鼠血管壁损伤模型中的凝块形成中患有严重的出血障碍和剧烈缺陷。我们假设GPR56是介导初始G蛋白12/13依赖性的血小板胶原蛋白受体血小板形状变化，而血小板则沿暴露的胶原蛋白滚动/转运到其稳定粘附部位血管伤口的滞后边缘。我们将研究血小板GPR56介导的G蛋白信号传导，血小板形状变化，体外血小板激活以及GPR56在止血的小鼠模型中的作用血栓形成。我们发现令人信服的初步证据表明，来自GPR56敲除小鼠的血小板急剧当小鼠血液在高处流过表面时，粘附在固定的胶原蛋白表面上有缺陷剪切力。我们建议GPR56不直接参与稳定的血小板粘附，而是血小板滚滚在整个胶原蛋白表面上，刺激GPR56会导致形状变化，使血小板稳定下通过不同的非GPCR胶原受体粘附。在在血小板上发现GPR56之前，我们提出了一个需要锚定受体N末端的AGPCR激活的一般模型，并剪切力介导受体解离，导致AGPCR束缚激动剂暴露于诱导G蛋白信号传导。这血小板传播的GPR56经历的条件与该理论模型非常相似。我们的工作还包括使用新开发的照片 - 链接激动剂探针进行生化研究以定义相关AGPCR，GPR56和GPR114的激动剂结合位点。