RhoA inactivation by p190RhoGAP regulates cell spreading and migration by promoting membrane protrusion and polarity
RhoA inactivation by p190RhoGAP regulates cell spreading and migration by promoting membrane protrusion and polarity
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DOI：
10.1091/mbc.12.9.2711
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发表时间：
2001-09-01
影响因子：
3.3
通讯作者：
Burridge, K
中科院分区：
文献类型：
--
作者：
Arthur, WT;Burridge, K
细胞外基质蛋白与整合素的结合通过调节Rho家族的小GTP酶而触发肌动蛋白细胞骨架的重排。调节Rho蛋白响应细胞外基质的活性变化的信号传导事件在很大程度上仍然未知。我们已经证明，在以前的研究中，整合素信号通过刺激p190 RhoGAP瞬时抑制RhoA活性。在这里，我们研究了通过操纵大鼠1成纤维细胞中的p190 RhoGAP信号转导的粘附依赖性RhoA失活的生物学意义。显性负性p190 RhoGAP的表达可拮抗粘附诱导的RhoA活性抑制。这导致纤连蛋白基质上的细胞铺展受损，细胞突起减少，应力纤维过早组装。相反，p190 RhoGAP的过表达增强了细胞的扩散。显性负性p190 RhoGAP升高细胞中RhoA在纤连蛋白上的活性并抑制迁移，而野生型GA-P的过表达降低RhoA活性，促进膜突起的形成，并增强运动性。表达显性负性p190 RhoGAP的细胞，而不是对照细胞或过表达野生型GAP的细胞，不能在迁移方向上建立极性。总之，这些数据表明，整合素触发的RhoA抑制p190 RhoGAP增强通过调节细胞突起和极性的扩展和迁移。
The binding of extracellular matrix proteins to integrins triggers rearrangements in the actin cytoskeleton by regulating the Rho family of small GTPases. The signaling events that mediate changes in the activity of Rho proteins in response to the extracellular matrix remain largely unknown. We have demonstrated in previous studies that integrin signaling transiently suppresses RhoA activity through stimulation of p190RhoGAP. Here, we investigated the biological significance of adhesion-dependent RhoA inactivation by manipulating p190RhoGAP signaling in Rat1 fibroblasts. The inhibition of RhoA activity that is induced transiently by adhesion was antagonized by expression of dominant negative p190RhoGAP. This resulted in impaired cell spreading on a fibronectin substrate, reduced cell protrusion, and premature assembly of stress fibers. Conversely, overexpression of p190RhoGAP augmented cell spreading. Dominant negative p190RhoGAP elevated RhoA activity in cells on fibronectin and inhibited migration, whereas overexpression of the wild-type GA-P decreased RhoA activity, promoted the formation of membrane protrusions, and enhanced motility. Cells expressing dominant negative p190RhoGAP, but not control cells or cells overexpressing the wild-type GAP, were unable to establish polarity in the direction of migration. Taken together, these data demonstrate that integrin-triggered RhoA inhibition by p190RhoGAP enhances spreading and migration by regulating cell protrusion and polarity.