Phosphatidylinositol 4,5-biphosphate (PIP2)-induced vesicle movement depends on N-WASP and involves Nck, WIP, and Grb2
Phosphatidylinositol 4,5-biphosphate (PIP2)-induced vesicle movement depends on N-WASP and involves Nck, WIP, and Grb2
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DOI：
10.1074/jbc.m204145200
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发表时间：
2002-10-04
影响因子：
4.8
通讯作者：
Rottner, K
中科院分区：
文献类型：
--
作者：
Benesch, S;Lommel, S;Rottner, K
Wiskott-Aldrich综合征蛋白（WASP）/Scar家族蛋白通过刺激Arp 2/3复合物的肌动蛋白成核活性来促进肌动蛋白聚合。虽然Scar/WAVE蛋白被认为参与板状伪足突出，但造血WASP已涉及各种基于肌动蛋白的过程，如趋化性、足体形成和吞噬作用。在这里，我们表明，普遍表达的N-WASP是必不可少的肌动蛋白组装在内膜表面诱导的结果增加磷脂酰肌醇4，5-二磷酸（PIP 2）水平。这一过程导致肌动蛋白彗星尖端的胞内囊泡运动，涉及Src同源3（SH 3）-SH 2衔接蛋白Nck和Grb 2以及WASP相互作用蛋白（WASP）的募集。通过表达各种N-WASP突变体蛋白在N-WASP缺陷细胞中重构囊泡运动揭示了三个能够与囊泡表面相互作用的独立结构域，其中WH 1和聚脯氨酸结构域都对N-WASP的募集和/或激活有显著贡献。与此相反，N-WASP与Rho-GTdR Cdc 42的直接相互作用对于囊泡运动的重建是不需要的。我们的数据揭示了N-WASP功能丧失的独特细胞表型，这增加了越来越多的证据表明，肌动蛋白和膜动力学之间的联系可能，至少部分地，反映了肌动蛋白为基础的运动囊泡通过细胞质。
Wiskott-Aldrich syndrome protein (WASP)/Scar family proteins promote actin polymerization by stimulating the actin-nucleating activity of the Arp2/3 complex. While Scar/WAVE proteins are thought to be involved in lamellipodia protrusion, the hematopoietic WASP has been implicated in various actin-based processes such as chemotaxis, podosome formation, and phagocytosis. Here we show that the ubiquitously expressed N-WASP is essential for actin assembly at the surface of endomembranes induced as a consequence of increased phosphatidylinositol 4,5-biphosphate (PIP2) levels. This process resulting in the motility of intracellular vesicles at the tips of actin comets involved the recruitment of the Src homology 3 (SH3)-SH2 adaptor proteins Nck and Grb2 as well as of WASP interacting protein (WIP). Reconstitution of vesicle movement in N-WASP-defective cells by expression of various N-WASP mutant proteins revealed three independent domains capable of interaction with the vesicle surface, of which both the WH1 and the polyproline domains contributed significantly to N-WASP recruitment and/or activation. In contrast, the direct interaction of N-WASP with the Rho-GTPase Cdc42 was not required for reconstitution of vesicle motility. Our data reveal a distinct cellular phenotype for N-WASP loss of function, which adds to accumulating evidence that the proposed link between actin and membrane dynamics may, at least partially, be reflected by the actin-based movement of vesicles through the cytoplasm.