How vinculin regulates force transmission
How vinculin regulates force transmission
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DOI：
10.1073/pnas.1216209110
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发表时间：
2013-06-11
影响因子：
11.1
通讯作者：
Garcia, Andres J.
中科院分区：
文献类型：
--
作者：
Dumbauld, David W.;Lee, Ted T.;Garcia, Andres J.
焦点粘连介导力在细胞外基质-整合素复合体和细胞骨架之间的传递。尽管纽蛋白与力量传递有关，但很少有直接的测量，也没有什么机械性的见解。使用表达纽蛋白突变体的纽蛋白缺失细胞，我们证明了纽蛋白不是粘附力和牵引力传递所必需的，而是肌球蛋白收缩依赖的粘附力和牵引力以及细胞面积和牵引力耦合所必需的。粘附力和牵引力取决于纽蛋白头部(V-H)和尾部结构域。V-H通过增加ECM结合的整合素-Talin复合体来增强粘连强度，而不依赖于与vinculin尾部配体的相互作用和收缩能力。与V-H相比，全长、自身抑制缺陷的突变体(T12)增加了粘附力，这意味着纽蛋白激活和肌动蛋白结合尾巴的作用。与粘附力相反，依赖纽蛋白的牵引力绝对需要全长和激活的分子；V-H没有任何影响。为了获得最大的力响应，需要头域和尾域的物理链接。纽蛋白在局灶性粘连中的停留时间与作用力有关，但与T12或V-H无关，支持机械敏感的纽蛋白激活模型，在该模型中，作用力稳定纽蛋白的活性构象，以促进力的转移。
Focal adhesions mediate force transfer between ECM-integrin complexes and the cytoskeleton. Although vinculin has been implicated in force transmission, few direct measurements have been made, and there is little mechanistic insight. Using vinculin-null cells expressing vinculin mutants, we demonstrate that vinculin is not required for transmission of adhesive and traction forces but is necessary for myosin contractility-dependent adhesion strength and traction force and for the coupling of cell area and traction force. Adhesion strength and traction forces depend differentially on vinculin head (V-H) and tail domains. V-H enhances adhesion strength by increasing ECM-bound integrin-talin complexes, independently from interactions with vinculin tail ligands and contractility. A full-length, autoinhibition-deficient mutant (T12) increases adhesion strength compared with V-H, implying roles for both vinculin activation and the actin-binding tail. In contrast to adhesion strength, vinculin-dependent traction forces absolutely require a full-length and activated molecule; V-H has no effect. Physical linkage of the head and tail domains is required for maximal force responses. Residence times of vinculin in focal adhesions, but not T12 or V-H, correlate with applied force, supporting a mechanosensitive model for vinculin activation in which forces stabilize vinculin's active conformation to promote force transfer.