Localized RhoA activation as a requirement for the induction of membrane ruffling
Localized RhoA activation as a requirement for the induction of membrane ruffling
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DOI：
10.1091/mbc.e04-12-1076
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发表时间：
2005-09-01
影响因子：
3.3
通讯作者：
Matsuda, M
中科院分区：
文献类型：
--
作者：
Kurokawa, K;Matsuda, M
我们利用荧光共振能量转移原理的探针检测了RhoA在迁移细胞和生长因子刺激细胞中的时空活性。在HeLa细胞迁移在一个低的细胞密度，RhoA被激活的收缩尾部和前缘。然而，RhoA仅在MDCK细胞作为单层片迁移的前缘被激活。在生长因子刺激的Cos1和NIH3T3细胞中，RhoA的活性在质膜上大大降低，但在新生板状伪足的膜皱褶处仍保持较高的活性。这些观察结果与RhoA在应激纤维形成中所起的作用一致，但它们也涉及RhoA调节膜皱褶，其诱导是活化Rac的典型表型。与此观点一致，显性负性RhoA被发现抑制活性Rac诱导的膜皱褶。此外，我们发现，Cdc42活性也需要高RhoA活性膜皱褶。最后，我们发现mDia1，而不是ROCK，与膜皱褶稳定相关。总之，这些结果表明，RhoA与Rac1和Cdc42合作，通过募集mDia诱导膜皱褶。
We examined the spatio-temporal activity of RhoA in migrating cells and growth factor-stimulated cells by using probes based on the principle of fluorescence resonance energy transfer. In HeLa cells migrating at a low cell density, RhoA was activated both at the contractile tail and at the leading edge. However, RhoA was activated only at the leading edge in MDCK cells migrating as a monolayer sheet. In growth factor-stimulated Cos1 and NIH3T3 cells, the activity of RhoA was greatly decreased at the plasma membrane, but remained high at the membrane ruffles in nascent lamellipodia. These observations are in agreement with the proposed role played by RhoA in stress fiber formation, but they also implicated RhoA in the regulation of membrane ruffling, the induction of which is a typical phenotype of activated Rac. In agreement with this view, dominant negative RhoA was found to inhibit membrane ruffling induced by active Rac. Furthermore, we found that Cdc42 activity was also required for high RhoA activity in membrane ruffles. Finally, we found that mDia1, but not ROCK, was stably associated with membrane ruffles. In conclusion, these results suggested that RhoA cooperates with Rac1 and Cdc42 to induce membrane ruffles via the recruitment of mDia.