Graduate program in Molecular, Cellular, Developmental, and Neural Biology, University at Albany, State University of New York, Albany, New York, USA.
Dev Dyn. 2011 Sep;240(9):2069-83. doi: 10.1002/dvdy.22714.
Cleft formation is the initial step of branching morphogenesis in many organs. We previously demonstrated that ROCK 1 regulates a nonmuscle myosin II-dependent mechanochemical checkpoint to transition initiated clefts to progressing clefts in developing submandibular salivary glands. Here, we report that ROCK-mediated integrin activation and subsequent formation of focal adhesion complexes comprise this mechanochemical checkpoint. Inhibition of ROCK1 and nonmuscle myosin II activity decreased integrin β1 activation in the cleft region and interfered with localization and activation of focal adhesion complex proteins, such as focal adhesion kinase (FAK). Inhibition of FAK activity also prevented cleft progression, by disrupting recruitment of the focal adhesion proteins talin and vinculin and subsequent fibronectin assembly in the cleft region while decreasing ERK1/2 activation. These results demonstrate that inside-out integrin signaling leading to a localized recruitment of active FAK-containing focal adhesion protein complexes generates a mechanochemical checkpoint that facilitates progression of branching morphogenesis.
裂隙形成是许多器官分支形态发生的初始步骤。我们之前的研究表明，ROCK1 调节非肌肉肌球蛋白 II 依赖性的机械化学检查点，将起始的裂隙转换为发育中的颌下唾液腺中的进行中的裂隙。在这里，我们报告 ROCK 介导的整合素激活以及随后形成的焦点粘附复合物构成了这个机械化学检查点。ROCK1 和非肌肉肌球蛋白 II 活性的抑制减少了裂隙区域中整合素β1 的激活，并干扰了焦点粘附复合物蛋白（如粘着斑激酶（FAK））的定位和激活。粘着斑激酶（FAK）活性的抑制也通过破坏粘着斑蛋白 talin 和 vinculin 的募集以及随后在裂隙区域中纤维连接蛋白的组装，同时减少 ERK1/2 的激活，从而阻止了裂隙的进展。这些结果表明，导致局部募集活性 FAK 含有焦点粘附蛋白复合物的内-外整合素信号产生了一个机械化学检查点，促进了分支形态发生的进展。
