Vinculin is a universal adaptor protein that transiently reinforces the mechanical stability of adhesion complexes. It stabilizes mechanical connections that cells establish between the actomyosin cytoskeleton and the extracellular matrix via integrins or to neighboring cells via cadherins, yet little is known regarding its mechanical design. Vinculin binding sites (VBSs) from different nonhomologous actin-binding proteins use conserved helical motifs to associate with the vinculin head domain. We studied the mechanical stability of such complexes by pulling VBS peptides derived from talin, α-actinin, and Shigella IpaA out of the vinculin head domain. Experimental data from atomic force microscopy single-molecule force spectroscopy and steered molecular dynamics (SMD) simulations both revealed greater mechanical stability of the complex for shear-like than for zipper-like pulling configurations. This suggests that reinforcement occurs along preferential force directions, thus stabilizing those cytoskeletal filament architectures that result in shear-like pulling geometries. Large force-induced conformational changes in the vinculin head domain, as well as protein-specific fine-tuning of the VBS sequence, including sequence inversion, allow for an even more nuanced force response.

中文翻译：

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不同的 Vinculin 结合位点使用相同的机制来调节定向力转导

Vinculin 是一种通用接头蛋白，可瞬时增强粘附复合物的机械稳定性。它稳定了细胞在肌动球蛋白细胞骨架和细胞外基质之间通过整合素或通过钙粘蛋白与邻近细胞建立的机械连接，但对其机械设计知之甚少。来自不同非同源肌动蛋白结合蛋白的长春花蛋白结合位点 (VBS) 使用保守的螺旋基序与长春花蛋白头域相关联。我们通过将来自 talin、α-辅肌动蛋白和志贺氏菌 IpaA 的 VBS 肽从纽蛋白头域中拉出来研究此类复合物的机械稳定性。来自原子力显微镜单分子力谱和转向分子动力学 (SMD) 模拟的实验数据都表明，剪切样复合物的机械稳定性比拉链样拉动配置更高。这表明强化沿优先力方向发生，从而稳定那些导致剪切样拉动几何形状的细胞骨架细丝结构。纽蛋白头域中由力引起的巨大构象变化，以及 VBS 序列的蛋白质特异性微调，包括序列倒置，可以实现更细微的力响应。从而稳定那些导致剪切样拉动几何形状的细胞骨架细丝结构。纽蛋白头域中由力引起的巨大构象变化，以及 VBS 序列的蛋白质特异性微调，包括序列倒置，可以实现更细微的力响应。从而稳定那些导致剪切样拉动几何形状的细胞骨架细丝结构。纽蛋白头域中由力引起的巨大构象变化，以及 VBS 序列的蛋白质特异性微调，包括序列倒置，可以实现更细微的力响应。