Structural aspects of urokinase receptor in vascular biology

描述(申请人提供)：尿激酶型纤溶酶原激活剂(UPA)及其细胞表面受体(UPAR)介导表面结合的纤溶酶原激活，已被认为在血管生物学中的几个重要生物学过程中发挥重要作用，包括血栓溶解、细胞黏附、细胞迁移、炎症、信号转导、血管生成和趋化作用。因此，对该系统的研究对于了解肿瘤侵袭、肿瘤转移、新生内膜形成、感染人类免疫缺陷病毒-1(HIV-1)、阿尔茨海默病和多发性硬化症等血管疾病的原因、预防和治疗至关重要。UPAR/uPA系统这些广泛的生理和病理生理作用的分子基础来自于uPAR与许多不同的配体相互作用的能力，例如uPA、Vitronectin、整合素(31、32、33)、LRP、GPCR，以及这些蛋白质-蛋白质相互作用引起的动态构象变化。首席调查者的最新结果(Huai，et al.《人尿激酶型纤溶酶原激活剂在复合体中的结构》，《科学》，2006年出版)暗示了uPAR的构象灵活性。这项提议的目标是系统地研究uPAR与其配体之间相互作用的结构基础和动力学性质。主要研究人员建议研究可溶性uPAR(SuPAR)(目标1)、Vitronectin络合物中的suPAR(目标2)、全长uPA络合物中的suPAR(目标3)，并比较和分析suPAR和suPAR配体络合物的结构(目标4)。蛋白质X射线结晶学将是研究这些蛋白质-蛋白质相互作用的主要工具，但也将使用其他常见的分子和细胞生物学技术。首席研究员已经建立了产生所需试剂的方法，并已经制作了几个初步的超PAR配体晶体，为这些拟议的研究提供了坚实的基础。这些对uPAR及其具有重要生理意义的uPA形式和Vitronectin的复合体的系统结构研究将了解uPAR与其配体之间的动态相互作用，一致地识别提供治疗可及性的受体和配体上的结合决定因素，并为未来设计和优化小分子拮抗剂以调节这些蛋白质-蛋白质相互作用并干预这些相互作用所导致的病理后果提供一个框架。

DESCRIPTION (provided by applicant): Urokinase plasminogen activator (uPA) together with its cell surface receptor (uPAR) mediates surface-bound plasminogen activation and has been recognized to play essential roles in several biological processes important in vascular biology, including clot lysis, cell adhesion, cell migration, inflammation, signal transduction, angiogenesis, and chemotaxis. Therefore, the study of this system will be critical to understand the causes, prevention, and treatment of vascular disorders and diseases including tumor invasion, tumor metastasis, neointima formation, infection with human immunodeficiency virus-1 (HIV-1), Alzheimer disease, and multiple sclerosis. The molecular basis for these broad physiological and pathophysiological roles of uPAR/uPA system stems from uPAR's capability to interact with many diverse ligands, e.g., uPA, vitronectin, integrins (31, 32, 33), LRP, GPCR, and the dynamic conformational changes caused by these protein-protein interactions. The principal investigator's recent results (Huai, et al. "Structure of Human Urokinase Plasminogen Activator in Complex", Science, in press, 2006) suggest conformational flexibility of uPAR. The goal of this proposal is to systematically study the structural basis and the dynamic nature of the interactions between uPAR and its ligands. The principal investigator proposes to study the structures of soluble uPAR (suPAR) (aim 1), suPAR in complex with vitronectin (aim 2), suPAR in complex with full- length uPA (aim 3), and to compare and analyze the structures of suPAR and suPAR-ligand complexes (aim 4). Protein X-ray crystallography will be the main tool to study these protein-protein interactions, but other common molecular and cell biology techniques will also be used. The principal investigator has established methods to generate needed reagents and has made several preliminary suPAR-ligand crystals, providing a solid basis for these proposed studies. These systematic structural studies of uPAR and its complexes with physiologically important uPA forms and vitronectin will understand the dynamic interactions between uPAR and its ligands, identify unanimously the binding determinants on the receptor and the ligands that confer therapeutic accessibility, and provide a framework for future design and optimization of small molecular antagonists to regulate these protein-protein interactions and to intervene the pathologic consequences resulting from these interactions.