GEF-H1 couples nocodazole-induced microtubule disassembly to cell contractility via RhoA
GEF-H1 couples nocodazole-induced microtubule disassembly to cell contractility via RhoA
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DOI：
10.1091/mbc.e07-12-1269
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发表时间：
2008-05-01
影响因子：
3.3
通讯作者：
Bokoch, Gary M.
中科院分区：
文献类型：
--
作者：
Chang, Yuan-Chen;Nalbant, Perihan;Bokoch, Gary M.
RhoA GTPase 在收缩性肌动蛋白-肌球蛋白丝（应力纤维）的组装以及培养物中贴壁单层细胞的相关粘着斑复合物的组装中发挥着至关重要的作用。 GEF-H1 是一种微管相关鸟嘌呤核苷酸交换因子，在从微管释放后激活 RhoA。 GEF-H1 的过度表达缺乏微管结合或用诺考达唑处理 HeLa 细胞以诱导微管解聚，导致 Rho 依赖性肌动蛋白应力纤维形成和收缩细胞形态。然而，GEF-H1 是否是必需的并且足以介导诺考达唑诱导的收缩性仍不清楚。我们在此确定，HeLa 细胞中 siRNA 介导的 GEF-H1 消耗可防止诺考达唑诱导的细胞收缩。此外，诺考达唑诱导的 RhoA 和 Rho 相关激酶 (ROCK) 介导肌球蛋白调节轻链 (MLC) 磷酸化在 GEF-H1 耗尽的细胞中受到损害。相反，重新引入 siRNA 抗性 GEF-H1 可恢复 RhoA 激活和收缩性。我们的研究揭示了 GEF-H1/RhoA/ROCK/MLC 信号通路在介导诺考达唑诱导的细胞收缩性中的关键作用。
The RhoA GTPase plays a vital role in assembly of contractile actin-myosin filaments (stress fibers) and of associated focal adhesion complexes of adherent monolayer cells in culture. GEF-H1 is a microtubule-associated guanine nucleotide exchange factor that activates RhoA upon release from microtubules. The overexpression of GEF-H1 deficient in microtubule binding or treatment of HeLa cells with nocodazole to induce microtubule depolymerization results in Rho-dependent actin stress fiber formation and contractile cell morphology. However, whether GEF-H1 is required and sufficient to mediate nocodazole-induced contractility remains unclear. We establish here that siRNA-mediated depletion of GEF-H1 in HeLa cells prevents nocodazole-induced cell contraction. Furthermore, the nocodazole-induced activation of RhoA and Rho-associated kinase ( ROCK) that mediates phosphorylation of myosin regulatory light chain (MLC) is impaired in GEF-H1-depleted cells. Conversely, RhoA activation and contractility are rescued by reintroduction of siRNA-resistant GEF-H1. Our studies reveal a critical role for a GEF-H1/RhoA/ROCK/MLC signaling pathway in mediating nocodazole- induced cell contractility.