Modulation of alpha 5 beta 1 integrin

α5β1整合素的调节

• 批准号: 6825832
• 负责人: DAVID E BOETTIGER
• 金额: $ 32.71万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 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 2008-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6825832
• 关键词: biophysics; cell adhesion; crosslink; fibronectins; fluorescence microscopy; integrins; intermolecular interaction; ligands; mutant; nanotechnology

DESCRIPTION (provided by applicant): The purpose of this proposal is to analyze the molecular mechanisms that govern integrin-ligand binding. Current analyses based on the solution of a crystal structure for alphavbeta3 have focused the conformational changes related to ligand binding. These conformational changes may be important for signaling as well as control of ligand binding. Nevertheless, in the context of the whole cell additional factors appear to contribute to the regulation of integrin-ligand binding and the strength of adhesion. The existence other factors have been Tong recognized as "avidity ". Although elements of the process, such as integrin clustering, have been associated with avidity, there is no clear mechanism to explain how these factors modulate adhesion. Part of the problem lies in the measurement of adhesion. The development of the spinning disc and chemical cross-linking methods provided tools to analyze the integrin-ligand binding interaction in the cell-substrate interface or contact zone. In this proposal, we plan to further develop the analysis to discriminate between measuring the number of integrin-ligand bonds that are formed and the strength of those bonds. These tools will be combined with laser tweezers and total internal reflection fluorescence microscopy to investigate a5b1-flbronectin binding in the contact zone. Results obtained in the previous funding period have shown that the binding parameters in the contact zone are very different from the binding of soluble ligand and generate a case in which the proportion of bound integrin can be regulated by the local density. Following the initial binding of alpha5beta1 to fibronectin, a5b1 becomes linked to the actin cytoskeleton which is in turn tensioned by the action of myosin motors. This will apply tension to the alpha5beta1-fibronectin bond (only as a post ligand-binding event). Results from the previous funding period show that there is a change in the alpha5beta1-fibronectin binding interface that occurs when tension is applied and can be detected by specific chemical cross-linking of alpha5beta1 to fibronectin.

描述（由申请人提供）：该提案的目的是分析控制整联蛋白 - 配体结合的分子机制。基于Alphavbeta3晶体结构的溶液的当前分析已集中于与配体结合有关的构象变化。这些构象变化对于信号传导以及对配体结合的控制可能很重要。然而，在整个细胞的背景下，其他因素似乎有助于调节整联蛋白 - 配体结合和粘附强度。存在其他因素被认为是“亲戚”。尽管该过程的元素（例如整联蛋白聚类）与亲和力有关，但没有明确的机制来解释这些因素如何调节粘附。问题的一部分在于粘附的测量。 旋转盘和化学交联方法的开发提供了分析细胞基底界面或接触区域中整合素体 - 配体结合相互作用的工具。在此提案中，我们计划进一步开发分析，以区分衡量形成的整合蛋白 - 配体键的数量以及这些键的强度。这些工具将与激光镊子和总内反射荧光显微镜结合使用，以研究接触区域中的A5B1-纤维蛋白结合。在上一个资金期间获得的结果表明，接触区中的结合参数与可溶性配体的结合非常不同，并产生了一个可以通过局部密度调节结构蛋白比例的情况。 在α5Beta1与纤连蛋白的初始结合后，A5B1与肌动蛋白细胞骨架有关，而肌动蛋白动物的作用又张紧了。这将对alpha5beta1-纤维蛋白键（仅作为后配体结合事件）应用张力。上一个融资期的结果表明，当施加张力时发生α5Beta1-纤维蛋白结合界面发生了变化，可以通过将α5Beta1的特定化学交联检测到纤维蛋白。