MECHANISTIC INSIGHTS INTO THE ?INSIDE-OUT? SIGNALING OF INTEGRINS

“由内而外”的机制洞察

• 批准号: 8364369
• 负责人: Marta Filizola
• 金额: $ 0.11万
• 依托单位: CARNEGIE-MELLON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-15 至 2013-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8364369
• 关键词: Adhesives; Affinity; Binding; Biological Process; Biomedical Research; Blood Platelets; Blood Vessels; Cell Adhesion; Cytoplasmic Tail; Dimerization; Extracellular Domain; Extracellular Matrix; Fibrinogen; Funding; Goals; Grant; Hemorrhage; High Performance Computing; Injury; Integrins; Lead; Ligands; Lipids; Mediating; Membrane; Membrane Proteins; Modeling; Molecular; Myocardial Infarction; National Center for Research Resources; Nature; Plasma Proteins; Platelet aggregation; Play; Positioning Attribute; Principal Investigator; Process; Proteins; Research; Research Activity; Research Infrastructure; Resources; Rest; Roentgen Rays; Role; Signal Transduction; Site; Solutions; Source; Specificity; Stroke; System; Talin; Thermodynamics; Thrombus; Transmembrane Domain; United States National Institutes of Health; computerized data processing; cost; insight; molecular dynamics; molecular recognition; programs; protein complex; research study; von Willebrand Factor; water environment

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. The overall goal of our research activities is to achieve a detailed mechanistic understanding of signal transduction processes triggered by molecular recognition in membrane protein complex systems. One of the funded research programs in our lab focuses on platelet integrin ?IIb?3, a membrane heterodimeric protein that mediates platelet aggregation by binding the adhesive plasma proteins fibrinogen and von Willebrand factor. This protein plays an essential role in initiating arrest of bleeding at sites of vascular injury, but also in thrombus formation, which may lead to heart attacks and stroke. Like other integrins, ?IIb?3 integrin can signal bidirectionally through long-range allosteric changes that are induced by the interactions of their short cytoplasmic tails with intracellular proteins such as talin (inside-out signaling), or by interactions of their extracellular domains with extracellular matrix components or soluble ligands (outside-in signaling). Interactions between the transmembrane (TM) helices of integrin ? and ? subunits have been suggested to play an important role in integrin activation and clustering. Notably, the TM helices are believed to interact in the integrin resting state, but to separate upon talin-induced integrin activation and cellular adhesion. However, the specificity and affinity between integrin TM helices have been difficult to demonstrate, and to relate to the activation process. Recent models derived from solution NMR and X-ray scattering experiments have clarified some details of the integrin TM interaction, but also raised questions about the atomic-level mechanism of the integrin signal processing. We propose to study the dynamical details of the interaction of the TM regions of integrin ?IIb and ?3 subunits in the presence or absence of talin, with the ultimate goal of understanding the molecular mechanism by which talin causes TM dimerization disruption. From a computational perspective, understanding the structural and thermodynamic features of integrin TM dimerization is not a trivial problem. To a large extent, this is due to the stochastic nature of this biological process, and the consequent need to perform multiple long-timescale molecular dynamics (MD) simulations of fully atomistic representations of protein complexes in an explicit lipid-water environment. Anton is uniquely positioned to provide detailed structural and dynamical information about the dimerization of integrin TM regions. Thus, we propose to carry out on Anton multiple microsecond-scale MD simulations, whose results are expected to provide breakthrough insights into the "inside-out" signaling of ?IIb?3 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， 包括其他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。 我们的研究活动的总体目标是实现一个详细的机械理解的信号转导过程中引发的膜蛋白复合物系统中的分子识别。我们实验室的一个受资助的研究项目集中在血小板整合素？联合调查局？3，一种膜异二聚体蛋白，通过结合粘附性血浆蛋白纤维蛋白原和血管性血友病因子介导血小板聚集。这种蛋白质在血管损伤部位开始止血方面起着重要作用，但也在血栓形成中起着重要作用，血栓形成可能导致心脏病发作和中风。像其他整合素一样，？联合调查局？3整联蛋白可以通过长距离变构变化发出双向信号，这些变化是由它们的短胞质尾部与塔林等细胞内蛋白质的相互作用（由内而外信号传导），或由它们的胞外域与细胞外基质成分或可溶性配体的相互作用（由外向内信号传导）诱导的。整合素跨膜螺旋之间的相互作用？然后呢？亚基在整联蛋白活化和聚集中起重要作用。值得注意的是，TM螺旋被认为在整合素静息状态下相互作用，但在塔林诱导的整合素活化和细胞粘附后分离。然而，整合素TM螺旋之间的特异性和亲和力一直难以证明，并涉及激活过程。最近的模型来自溶液NMR和X-射线散射实验澄清了整合素TM相互作用的一些细节，但也提出了有关整合素信号处理的原子级机制的问题。我们建议研究整合素的TM区域的相互作用的动力学细节？IIb和？3亚基的存在或不存在的塔林，与理解的分子机制，塔林导致TM二聚体破坏的最终目标。从计算的角度来看，理解整合素TM二聚化的结构和热力学特征不是一个微不足道的问题。在很大程度上，这是由于这种生物过程的随机性，以及随之而来的需要执行多个长时间尺度的分子动力学（MD）模拟的蛋白质复合物在一个明确的脂水环境中的完全原子化的表示。安东是唯一的定位，以提供详细的结构和动力学信息的二聚体的整合素TM区域。因此，我们建议进行安东多微秒尺度的MD模拟，其结果预计将提供突破性的见解到“内向外”的信号？联合调查局？3整合素。