Modulation of alpha 5 beta 1 integrin

α5β1整合素的调节

• 批准号: 6905578
• 负责人: DAVID E BOETTIGER
• 金额: $ 32.7万
• 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/6905578
• 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）：本提案的目的是分析控制整合素-配体结合的分子机制。目前基于 alphavbeta3 晶体结构解析的分析重点关注与配体结合相关的构象变化。这些构象变化对于信号传导以及配体结合的控制可能很重要。然而，在全细胞的背景下，其他因素似乎有助于调节整合素-配体结合和粘附强度。其他因素的存在被童认为是“贪欲”。尽管该过程的要素（例如整合素聚类）与亲和力相关，但没有明确的机制来解释这些因素如何调节粘附。部分问题在于粘附力的测量。 旋转盘和化学交联方法的发展提供了分析细胞-基质界面或接触区中整合素-配体结合相互作用的工具。在本提案中，我们计划进一步开发分析，以区分测量形成的整合素-配体键的数量和这些键的强度。这些工具将与激光镊子和全内反射荧光显微镜相结合，以研究接触区中的 a5b1-纤连蛋白结合。前期资助期间获得的结果表明，接触区的结合参数与可溶性配体的结合有很大不同，并产生了可以通过局部密度调节结合的整合素比例的情况。 α5β1 最初与纤连蛋白结合后，a5b1 与肌动蛋白细胞骨架相连，而肌动蛋白细胞骨架又通过肌球蛋白马达的作用而张紧。这将对 α5β1-纤连蛋白键施加张力（仅作为配体结合后事件）。上一资助期的结果表明，当施加张力时，α5β1-纤连蛋白结合界面会发生变化，并且可以通过 α5β1 与纤连蛋白的特定化学交联来检测。