Phosphorylation of RhoB by CK1 impedes actin stress fiber organization and epidermal growth factor receptor stabilization
Phosphorylation of RhoB by CK1 impedes actin stress fiber organization and epidermal growth factor receptor stabilization
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DOI：
10.1016/j.yexcr.2008.06.011
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发表时间：
2008-09-10
影响因子：
3.7
通讯作者：
Pradines, Anne
中科院分区：
文献类型：
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作者：
Tillement, Vanessa;Lajoie-Mazenc, Isabelle;Pradines, Anne
RhoB是一种与细胞骨架组织、EGF受体运输和细胞转化有关的小GTPase，它是一种即时早期基因，在其生物合成途径的许多水平上受到调节。在这里，我们发现丝氨酸/苏氨酸蛋白激酶CK1在体外磷酸化RhoB，但不磷酸化RhoA或RhoC。通过使用特异性CK1抑制剂IC261和D4476，我们发现该激酶在HeLa细胞中也能磷酸化RhoB。质谱分析表明RhoB在丝氨酸185的c端被CK1单磷酸化。在培养细胞中，Ala取代Ser185显著抑制RhoB的磷酸化。最后，我们发现CK1的抑制激活RhoB并促进RhoB依赖性肌动蛋白纤维的形成和EGF-R水平。我们的数据首次证明了RhoB磷酸化，并表明这种翻译后成熟将是控制RhoB功能的一种新的关键机制。(c) 2008爱思唯尔公司版权所有。
RhoB is a small GTPase implicated in cytoskeletal organization, EGF receptor trafficking and cell transformation, It is an immediate-early gene, regulated at many levels of its biosynthetic pathway. Herein we show that the serine/threonine protein kinase CK1 phosphorylates RhoB in vitro but not RhoA or RhoC. With the use of specific CK1 inhibitors, IC261 and D4476, we show that the kinase phosphorylates also RhoB in HeLa cells. Mass spectrometry analysis demonstrates that RhoB is monophosphorylated by CK1, in its C-terminal end, on serine 185. The substitution of Ser185 by Ala dramatically inhibited the phosphorylation of RhoB in cultured cells. Lastly we show that the inhibition of CK1 activates RhoB and promotes RhoB dependent actin fiber formation and EGF-R level. Our data provide the first demonstration of RhoB phosphorylation and indicate that this post-translational maturation would be a novel critical mechanism to control the RhoB functions. (c) 2008 Elsevier Inc. All rights reserved.