Unraveling Integrin Mechanotransduction with Molecular Imaging

 描述(申请人提供)：机械力是细胞功能的关键调节器，对组织的正常生长和动态平衡，以及对动脉粥样硬化、高血压、骨质疏松症和癌症等疾病都是如此。因此，了解细胞感知和响应机械力的机制对于理解正常生理和这些疾病状态至关重要。整合素介导的黏附提供了细胞传递和感知细胞外基质(ECM)和细胞内细胞骨架网络之间的机械力的主要联系。目前对机械传感的看法集中在“分子离合器”的概念上，该离合器将固定的、结合的整合素与向后移动的肌动蛋白细丝连接起来。这些连接是通过承载连接物分子，如Talin形成的。因此，力是由一个本质上动态的组件感知力的，其行为被机械力改变。了解这一系统的分子细节是该项目的目标。施瓦茨实验室已经开发出分子力传感器，可以在空间和时间上测量特定蛋白质的张力。我建议将Talin张力传感器与荧光散斑显微镜相结合，以可视化肌动蛋白细丝的组装、移动和拆卸。这种方法将允许在近单一分子水平上同时分析细胞粘连内的力和动力学。这将在改变细胞派生的力和外部施加的力的同时进行。确定作用力如何调节粘连内的分子动力学将为整合素介导的粘连的机械转导的分子机制提供基本的见解。

 DESCRIPTION (provided by applicant): Mechanical forces are key regulators of cellular function for both normal growth and homeostasis of tissues, and in diseases including atherosclerosis, hypertension, osteoporosis and cancer. Understanding the mechanisms by which cells sense and respond to mechanical forces is therefore critical for understanding normal physiology and these disease states. Integrin-mediated adhesions provide the primary linkage through which cells both transmit and sense mechanical forces between the extracellular matrix (ECM) and the cytoskeletal networks within the cell. Current views of mechanosensing center on the concept of a "molecular clutch" that connects the immobile, bound integrins to rearward moving actin filaments. These connections are formed through load-bearing linker molecules such as talin. Thus, forces are sensed by an intrinsically dynamic assembly whose behavior is modified by mechanical forces. Understanding this system in molecular detail is the goal of the project. The Schwartz lab has developed molecular force sensors that allow spatial and temporal measurement of tension across specific proteins. I propose to combine a talin tension sensor with fluorescent speckle microscopy for visualization of actin filament assembly, movement and disassembly. This approach will allow simultaneous analysis at near-single molecule levels of the forces and dynamics within cell adhesions. This will be done while varying both cell-derived and externally applied forces. Determining how forces modulate the molecular dynamics within the adhesions will provide fundamental insights into the molecular mechanisms of mechanotransduction by integrin-mediated adhesions.