Novel Coronin7 interactions with Cdc42 and N-WASP regulate actin organization and Golgi morphology.
Novel Coronin7 interactions with Cdc42 and N-WASP regulate actin organization and Golgi morphology.
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DOI：
10.1038/srep25411
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发表时间：
2016-05-04
影响因子：
4.6
通讯作者：
Rastetter RH
中科院分区：
文献类型：
--
作者：
Bhattacharya K;Swaminathan K;Peche VS;Clemen CS;Knyphausen P;Lammers M;Noegel AA;Rastetter RH
肌动蛋白细胞骨架对高尔基复合体独特结构的贡献是多方面的。在这一过程中，一个重要的参与者是Coronin7 (CRN7)，这是一种高尔基驻留蛋白，它稳定了反高尔基网络（TGN）中的f -肌动蛋白组装，从而促进了顺行运输。在这里，我们确定了crn7介导的f -肌动蛋白与高尔基体的关联是通过小Rho GTPase Cdc42和N-WASP明显调节的。我们确定了N-WASP是CRN7的一个新的相互作用伙伴，并证明CRN7通过抑制组成型Cdc42激活时N-WASP的“过度活性”来限制虚假的f -肌动蛋白重组。CRN7的缺失导致细胞f -肌动蛋白含量增加，并导致高尔基体结构的破坏。CRN7在其串联β-螺旋桨中含有Cdc42-和rac -相互作用结合（CRIB）基序，并选择性地与gdp结合的Cdc42N17突变体结合。我们推测CRN7可以作为Cdc42活性生成的辅助因子。CRIB基序残基的突变使Cdc42与CRN7的结合失效，也不能挽救来自CRN7 KO小鼠的成纤维细胞的细胞缺陷。Cdc42N17过表达部分挽救了KO表型，而N-WASP过表达则不能。我们得出结论，CRN7在时空上以Cdc42和n - wasp依赖的方式影响F-actin组织和高尔基体完整性。
The contribution of the actin cytoskeleton to the unique architecture of the Golgi complex is manifold. An important player in this process is Coronin7 (CRN7), a Golgi-resident protein that stabilizes F-actin assembly at the trans-Golgi network (TGN) thereby facilitating anterograde trafficking. Here, we establish that CRN7-mediated association of F-actin with the Golgi apparatus is distinctly modulated via the small Rho GTPase Cdc42 and N-WASP. We identify N-WASP as a novel interaction partner of CRN7 and demonstrate that CRN7 restricts spurious F-actin reorganizations by repressing N-WASP ‘hyperactivity’ upon constitutive Cdc42 activation. Loss of CRN7 leads to increased cellular F-actin content and causes a concomitant disruption of the Golgi structure. CRN7 harbours a Cdc42- and Rac-interactive binding (CRIB) motif in its tandem β-propellers and binds selectively to GDP-bound Cdc42N17 mutant. We speculate that CRN7 can act as a cofactor for active Cdc42 generation. Mutation of CRIB motif residues that abrogate Cdc42 binding to CRN7 also fail to rescue the cellular defects in fibroblasts derived from CRN7 KO mice. Cdc42N17 overexpression partially rescued the KO phenotypes whereas N-WASP overexpression failed to do so. We conclude that CRN7 spatiotemporally influences F-actin organization and Golgi integrity in a Cdc42- and N-WASP-dependent manner.