Kinley Andrew W, Weed Scott A, Weaver Alissa M, Karginov Andrei V, Bissonette Eric, Cooper John A, Parsons J Thomas
Department of Microbiology, Health Sciences Center, University of Virginia, Charlottesville, VA 22908, USA.
Curr Biol. 2003 Mar 4;13(5):384-93. doi: 10.1016/s0960-9822(03)00107-6.
Modulation of actin cytoskeleton assembly is an integral step in many cellular events. A key regulator of actin polymerization is Arp2/3 complex. Cortactin, an F-actin binding protein that localizes to membrane ruffles, is an activator of Arp2/3 complex.
A yeast two-hybrid screen revealed the interaction of the cortactin Src homology 3 (SH3) domain with a peptide fragment derived from a cDNA encoding a region of WASp-Interacting Protein (WIP). GST-cortactin interacted with WIP in an SH3-dependent manner. The subcellular localization of cortactin and WIP coincided at the cell periphery. WIP increased the efficiency of cortactin-mediated Arp2/3 complex activation of actin polymerization in a concentration-dependent manner. Lastly, coexpression of cortactin and WIP stimulated membrane protrusions.
WIP, a protein involved in filopodia formation, binds to both actin monomers and cortactin. Thus, recruitment of actin monomers to a cortactin-activated Arp2/3 complex likely leads to the observed increase in cortactin activation of Arp2/3 complex by WIP. These data suggest that a cortactin-WIP complex functions in regulating actin-based structures at the cell periphery.
肌动蛋白细胞骨架组装的调节是许多细胞事件中的一个重要步骤。肌动蛋白聚合的关键调节因子是Arp2/3复合体。皮层肌动蛋白，一种定位于膜皱褶的F-肌动蛋白结合蛋白，是Arp2/3复合体的激活剂。
酵母双杂交筛选揭示了皮层肌动蛋白Src同源结构域3（SH3）与源自编码WASp相互作用蛋白（WIP）区域的cDNA的肽片段之间的相互作用。GST-皮层肌动蛋白以SH3依赖的方式与WIP相互作用。皮层肌动蛋白和WIP的亚细胞定位在细胞周边一致。WIP以浓度依赖的方式提高了皮层肌动蛋白介导的Arp2/3复合体激活肌动蛋白聚合的效率。最后，皮层肌动蛋白和WIP的共表达刺激了膜突起。
WIP是一种参与丝状伪足形成的蛋白质，它与肌动蛋白单体和皮层肌动蛋白都结合。因此，肌动蛋白单体向皮层肌动蛋白激活的Arp2/3复合体的募集可能导致观察到的WIP对皮层肌动蛋白激活Arp2/3复合体的增加。这些数据表明，皮层肌动蛋白-WIP复合体在调节细胞周边基于肌动蛋白的结构中起作用。
