Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France.
Nat Commun. 2020 Jun 19;11(1):3116. doi: 10.1038/s41467-020-16922-1.
Cells reinforce adhesion strength and cytoskeleton anchoring in response to the actomyosin force. The mechanical stretching of talin, which exposes cryptic vinculin-binding sites, triggers this process. The binding of RIAM to talin could regulate this mechanism. However, the mechanosensitivity of the talin-RIAM complex has never been tested. It is also not known whether RIAM controls the mechanosensitivity of the talin-vinculin complex. To address these issues, we designed an in vitro microscopy assay with purified proteins in which the actomyosin force controls RIAM and vinculin-binding to talin. We demonstrate that actomyosin triggers RIAM dissociation from several talin domains. Actomyosin also provokes the sequential exchange of RIAM for vinculin on talin. The effect of RIAM on this force-dependent binding of vinculin to talin varies from one talin domain to another. This mechanism could allow talin to biochemically code a wide range of forces by selecting different combinations of partners.
细胞通过加强黏附强度和细胞骨架锚定来响应肌动球蛋白的力。该过程由肌球蛋白触发，肌球蛋白可拉伸 talin，暴露出隐藏的 vinculin 结合位点。RIAM 与 talin 的结合可以调节这一机制。然而，talin-RIAM 复合物的机械敏感性从未被测试过。也不知道 RIAM 是否控制 talin-vinculin 复合物的机械敏感性。为了解决这些问题，我们设计了一种体外显微镜检测方法，使用纯化的蛋白质，其中肌动球蛋白控制 RIAM 和 vinculin 与 talin 的结合。我们证明肌动球蛋白触发 RIAM 从 talin 的几个结构域解离。肌动球蛋白还引发了 RIAM 与 talin 上的 vinculin 的顺序交换。RIAM 对 vinculin 与 talin 这种依赖于力的结合的影响因 talin 结构域的不同而不同。这种机制可以通过选择不同的结合伙伴，使 talin 通过生物化学编码来传递广泛的力。
