Lowry William E, Huang Jianyun, Ma Yong-Chao, Ali Shariq, Wang Dongxia, Williams Daniel M, Okada Masato, Cole Philip A, Huang Xin-Yun
Department of Physiology, Cornell University, Weill Medical College, New York, New York 10021, USA.
Dev Cell. 2002 Jun;2(6):733-44. doi: 10.1016/s1534-5807(02)00175-2.
Heterotrimeric G proteins can signal to reorganize the actin cytoskeleton, but the mechanism is unclear. Here we report that, in tyrosine kinase Csk-deficient mouse embryonic fibroblast cells, G protein (Gbetagamma, Galpha(12), Galpha(13), and Galpha(q))-induced, and G protein-coupled receptor-induced, actin stress fiber formation was completely blocked. Reintroduction of Csk into Csk-deficent cells restored the G protein-induced actin stress fiber formation. Chemical rescue experiments with catalytic mutants of Csk demonstrated that the catalytic activity of Csk was required for this process. Furthermore, we uncovered that Gbetagamma can both translocate Csk to the plasma membrane and directly increase Csk kinase activity. Our genetic and biochemical studies demonstrate that Csk plays a critical role in mediating G protein signals to actin cytoskeletal reorganization.
异源三聚体G蛋白能够发出信号以重组肌动蛋白细胞骨架，但其机制尚不清楚。在此我们报告，在酪氨酸激酶Csk缺陷的小鼠胚胎成纤维细胞中，G蛋白（Gβγ、Gα12、Gα13和Gαq）诱导的以及G蛋白偶联受体诱导的肌动蛋白应力纤维形成被完全阻断。将Csk重新导入Csk缺陷细胞可恢复G蛋白诱导的肌动蛋白应力纤维形成。用Csk的催化突变体进行的化学拯救实验表明，此过程需要Csk的催化活性。此外，我们发现Gβγ既能将Csk转运至质膜，又能直接提高Csk激酶活性。我们的遗传学和生物化学研究表明，Csk在介导G蛋白信号至肌动蛋白细胞骨架重组过程中起关键作用。
