SAXS STUDIES ON FULL-LENGTH DETERGENT SOLUBILIZED INTEGRINS

这个子项目是许多利用资源的研究子项目之一 由NIH/NCRR资助的中心拨款提供。子项目的主要支持 而子项目的主要调查员可能是由其他来源提供的， 包括其它NIH来源。 列出的子项目总成本可能 代表子项目使用的中心基础设施的估计数量， 而不是由NCRR赠款提供给子项目或子项目工作人员的直接资金。 整合素是细胞表面受体，对发育、伤口愈合、 止血、免疫和癌症。功能性整联蛋白通常非共价连接 a和B亚基的异二聚体。通常，整联蛋白不具有内在的酶促能力， 并通过细胞质衔接分子将信号信息处理到细胞中， 招募下游效应者。整合素活性的调节是双向的， 除了细胞外配体结合（由外向内信号传导）;细胞内队列（由内而外 信号传导）可以控制整联蛋白功能。然而，尽管它在生理上很重要， 目前还不清楚这些受体如何处理信号信息， 全长受体整合素的激活需要协调和调节，否则可能 导致疾病状态，例如血栓性疾病和止血受损。在 非活性状态整联蛋白具有直径约为140 μ m的紧凑结构， 延伸至~250-300磅。 为了了解整合素的激活和调节，我们建议使用小角度X射线 用去污剂溶解的全长整联蛋白进行SAXS散射。本项目的目标 主要是：1）在缓冲液条件下测定溶液中整联蛋白的整体构象 稳定非活性或活性构象，和2）表征构象 在从非活性构象到活性构象的转变过程中发生变化。预期结果将 在理解整合素如何通过蛋白质双向处理信号中至关重要。 膜，并提供重要的见解，以分子机制的基础上广泛的 各种止血疾病，如Glanzman血栓无力症。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Integrins are cell surface receptors that are important for development, wound healing, hemostasis, immunity and cancer. Functional integrins are typically non-covalent linked heterodimers of a and b subunits. Generally, integrins do not have intrinsic enzymatic ability and process signaling information into the cell through cytoplasmic adaptor molecules that recruit downstream effectors. Regulation of integrin activity is bidirectional in that in addition to extracellular ligand binding (outside-in signaling); intracellular queues (insideout signaling) can control integrin function. Despite its physiological importance, however, it is still unclear how these receptors process signaling information in the context of the full-length receptor. Activation of integrins needs to be coordinated and regulated or it may lead to diseased states, such as thrombotic disease and impairment of hemostasis. In the inactive state integrins have a compact structure with a diameter of ~140¿ and when activated extends to ~250-300¿. To understand integrins' activation and regulation, we propose to use small angle X-ray scattering (SAXS) with detergent solubilized full-length integrins. The goals of this project are: 1) to determine the overall conformation of integrins in solution with buffer conditions that stabilize inactive or active conformations, and 2) characterize the conformational changes during the transition from inactive to active conformations. The expected results will be essential in the understanding of how integrins process signals bidirectionally through the membrane and provide important insights into the molecular mechasnisms underlying a wide assortment of hemostatic diseases, such as Glanzman's thrombasthenia.