Analysis of Enabled (Ena) and GUK-holder (GUKh) in regulating WAVE-driven actin dynamics in Drosophila

肌动蛋白细胞骨架在形态发生过程中提供机械力来驱动细胞形状的改变和细胞的迁移。肌动蛋白聚合是由WASP/WAVE蛋白家族的成员控制的，WAVE蛋白家族成员激活了肌动蛋白核复合体Arp2/3。黄蜂和WAVE存在于多蛋白复合体中，调节果蝇发育过程中Arp2/3功能的不同方面。我们最近的结构-功能分析揭示了波复合体成员和不同的肌动蛋白辅助蛋白之间复杂的相互作用。我们已经发现，WAVE复合体的中央亚单位Abi直接与果蝇肌动蛋白延长器使能(Ena)的EVH1结构域结合。这种相互作用对体内波的复合功能至关重要。Ena是如何调节体内波活动的？我们将继续对ENA在果蝇发育过程中调节波功能的作用进行分子分析。此外，我们还开始了GUK-HOLDER(GUKh)的遗传和生化分析，GUKh是一个含有蛋白质的保守的波同源结构域。免疫共沉淀实验证明GUKh与波复合体成员之间存在相互作用。活体成像研究表明，GUKh显示出微管+末端跟踪能力，并将Abi招募到微管。我们未来研究的目标是了解GUKH如何作用于波功能，以及GUKH如何在体内整合肌动蛋白和微管动力学。

The actin cytoskeleton provides mechanical forces to drive cell shape changes and cell migration during morphogenesis. Actin polymerization is controlled by members of the WASP/WAVE protein family that activate the actin nucleating complex Arp2/3. WASP and WAVE exist in multi-protein complexes regulating distinct aspects of Arp2/3 function in Drosophila development. Our recent structure-function analyses revealed an intricate interplay between members of the WAVE complex and different actin accessory proteins. We have found that the central subunit of the WAVE complex, Abi binds directly to the EVH1 domain of the actin elongator Enabled (Ena) in Drosophila. This interaction is crucial for WAVE complex function in vivo. How does Ena regulate WAVE activity in vivo? We will continue our molecular analysis of the role of Ena in regulating WAVE function during Drosophila development. In addition, we started a genetic and biochemical analysis of GUK-holder (GUKh), a conserved WAVE homology domain containing protein. Co-immunoprecipitation experiments demonstrate an interaction between GUKh and members of the WAVE complex. Live-imaging studies revealed that GUKh exhibit microtubule plus end tracking ability and recruits Abi to microtubules. The goal of our future studies is to understand how GUKh acts on WAVE function and how GUKh might integrate actin and microtubule dynamics in vivo.