Guanine Nucleotide Exchange Factor-H1 Regulates Cell Migration via Localized Activation of RhoA at the Leading Edge
Guanine Nucleotide Exchange Factor-H1 Regulates Cell Migration via Localized Activation of RhoA at the Leading Edge
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DOI：
10.1091/mbc.e09-01-0041
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发表时间：
2009-09-15
影响因子：
3.3
通讯作者：
Bokoch, Gary M.
中科院分区：
文献类型：
--
作者：
Nalbant, Perihan;Chang, Yuan-Chen;Bokoch, Gary M.
在Rho家族gtpase的控制下，细胞迁移涉及肌动蛋白和微管细胞骨架的协同重组，以及细胞底物粘附的周转。RhoA在运动细胞的前沿被未知机制激活，以控制肌动蛋白应力纤维的组装，收缩性和焦点粘附动力学。微管相关鸟嘌呤核苷酸交换因子(GEF)-H1从微管释放时激活RhoA，启动RhoA/ rho激酶/肌球蛋白轻链信号通路，调节细胞收缩性。然而，激活的GEF-H1对细胞迁移过程中细胞骨架动力学协调的贡献尚不清楚。我们发现，由于GEF-H1的Rho交换活性的丧失，小干扰rna诱导的GEF-H1耗尽导致HeLa细胞定向迁移减少。利用活细胞生物传感器分析RhoA活性，发现GEF-H1控制RhoA前缘的局部激活。GEF-H1的缺失与前缘肌动蛋白动力学的改变以及焦点粘附寿命的增加有关。在GEF-H1/RhoA信号缺失的情况下，酪氨酸磷酸化的局灶黏附激酶和paxillin对局灶黏附动力学的调控至关重要。本研究通过对细胞边缘RhoA活性的局部调控，确定了GEF-H1是细胞迁移的关键结构和信号组分的关键组织者。
Cell migration involves the cooperative reorganization of the actin and microtubule cytoskeletons, as well as the turnover of cell-substrate adhesions, under the control of Rho family GTPases. RhoA is activated at the leading edge of motile cells by unknown mechanisms to control actin stress fiber assembly, contractility, and focal adhesion dynamics. The microtubule-associated guanine nucleotide exchange factor (GEF)-H1 activates RhoA when released from microtubules to initiate a RhoA/Rhokinase/ myosin light chain signaling pathway that regulates cellular contractility. However, the contributions of activated GEF-H1 to coordination of cytoskeletal dynamics during cell migration are unknown. We show that small interfering RNA-induced GEF-H1 depletion leads to decreased HeLa cell directional migration due to the loss of the Rho exchange activity of GEF-H1. Analysis of RhoA activity by using a live cell biosensor revealed that GEF-H1 controls localized activation of RhoA at the leading edge. The loss of GEF-H1 is associated with altered leading edge actin dynamics, as well as increased focal adhesion lifetimes. Tyrosine phosphorylation of focal adhesion kinase and paxillin at residues critical for the regulation of focal adhesion dynamics was diminished in the absence of GEF-H1/RhoA signaling. This study establishes GEF-H1 as a critical organizer of key structural and signaling components of cell migration through the localized regulation of RhoA activity at the cell leading edge.