RhoA/ROCK-mediated switching between Cdc42- and Rac1-dependent protrusion in MTLn3 carcinoma cells
RhoA/ROCK-mediated switching between Cdc42- and Rac1-dependent protrusion in MTLn3 carcinoma cells
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DOI：
10.1016/j.yexcr.2008.01.016
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发表时间：
2008-04-15
影响因子：
3.7
通讯作者：
Backer, Jonathan M.
中科院分区：
文献类型：
--
作者：
El-Sibai, Mirvat;Pertz, Olivier;Backer, Jonathan M.
Rho GTP酶是作用于肌动蛋白细胞骨架的多功能细胞形状调节剂。使用Rho GT3突变体的研究表明，在某些细胞中，Rac 1和Cdc 42分别在前缘调节片状伪足和丝状伪足的形成，而RhoA介导运动细胞后部的收缩。然而，最近的报道已经描述了在经历运动的细胞的前部的RhoA/ROCK激活区。在这项研究中，我们使用基于FRET的RhoA生物传感器来显示RhoA激活定位于EGF刺激的细胞的前沿。Rho或ROCK的抑制增强了突起，但显著抑制了细胞运动;这些变化与细胞边缘的Rac-1的显著激活相关。令人惊讶的是，尽管对照MTLn 3细胞中EGF刺激的突起是Rac非依赖性和Cdc 42依赖性的，但在ROCK抑制后在MTLn 3细胞中观察到相反的模式。因此，Rho和ROCK在前沿抑制Rac-1活化，并且ROCK的抑制导致Cdc 42和Rac-1之间的转换，作为癌细胞中的主要Rho GT3驱动突起。这些数据描述了Rho在Rac和Cdc 42协调信号传导中的新作用。(C)2008年爱思唯尔公司All rights reserved.
Rho GTPases are versatile regulators of cell shape that act on the actin cytoskeleton. Studies using Rho GTPase mutants have shown that, in some cells, Rac1 and Cdc42 regulate the formation of lamellipodia and filopodia, respectively at the leading edge, whereas RhoA mediates contraction at the rear of moving cells. However, recent reports have described a zone of RhoA/ROCK activation at the front of cells undergoing motility. In this study, we use a FRET-based RhoA biosensor to show that RhoA activation localizes to the leading edge of EGF-stimulated cells. Inhibition of Rho or ROCK enhanced protrusion, yet markedly inhibited cell motility; these changes correlated with a marked activation of Rac-1 at the cell edge. Surprisingly, whereas EGF-stimulated protrusion in control MTLn3 cells is Rac-independent and Cdc42-dependent, the opposite pattern is observed in MTLn3 cells after inhibition of ROCK. Thus, Rho and ROCK suppress Rac-1 activation at the leading edge, and inhibition of ROCK causes a switch between Cdc42 and Rac-1 as the dominant Rho GTPase driving protrusion in carcinoma cells. These data describe a novel role for Rho in coordinating signaling by Rac and Cdc42. (C) 2008 Elsevier Inc. All rights reserved.