Detection and conversion of mechanical forces into biochemical signals controls cell functions during physiological and pathological processes. Mechanosensing is based on protein deformations and reorganizations, yet the molecular mechanisms are still unclear. Using a cell-stretching device compatible with super-resolution microscopy and single-protein tracking, we explored the nanoscale deformations and reorganizations of individual proteins inside mechanosensitive structures. We achieved super-resolution microscopy after live stretching on intermediate filaments, microtubules and integrin adhesions. Simultaneous single-protein tracking and stretching showed that while integrins followed the elastic deformation of the substrate, actin filaments and talin also displayed lagged and transient inelastic responses associated with active acto-myosin remodelling and talin deformations. Capturing acute reorganizations of single molecules during stretching showed that force-dependent vinculin recruitment is delayed and depends on the maturation of integrin adhesions. Thus, cells respond to external forces by amplifying transiently and locally cytoskeleton displacements, enabling protein deformation and recruitment in mechanosensitive structures.

机械力的检测和转换为生化信号可控制生理和病理过程中的细胞功能。机械感测是基于蛋白质的变形和重组，但分子机制仍不清楚。使用与超分辨率显微镜和单蛋白跟踪兼容的细胞拉伸设备，我们探索了机械敏感结构内部单个蛋白的纳米级变形和重组。在中间丝，微管和整联蛋白粘附物上实时拉伸后，我们获得了超分辨率显微镜。同时进行单蛋白跟踪和拉伸表明，整联蛋白会随着底物的弹性变形而变化，肌动蛋白丝和塔林蛋白也表现出滞后和短暂的无弹性反应，与主动肌球蛋白重塑和塔林蛋白变形有关。在拉伸过程中捕获单个分子的急性重组表明，力依赖性新蛋白募集被延迟，并且取决于整联蛋白粘附的成熟。因此，细胞通过放大瞬时和局部细胞骨架位移来响应外力，从而使蛋白变形和募集到机械敏感结构中。