Regulation of formins and cell polarity

 描述（由申请人提供）：本研究的目的是确定肌动蛋白细胞骨架的组装动力学和结构如何受formins和调节其活性的细胞机制控制。我们正在芽殖酵母中研究这个问题，在芽殖酵母中，形成蛋白组装具有极化细胞生长所需的特征长度、结构和动力学的肌动蛋白电缆。此外，我们将这项工作扩展到哺乳动物的呼吸调节。该提案的重点是在前一个资金周期中发现的几种新的多组分机制，这些机制控制着formin介导的肌动蛋白成核，或formin介导的肌动蛋白丝伸长事件的持续时间和速度。该项目结合了遗传学、活细胞成像、生物化学和新颖的多波长单分子TIRF显微镜。目标是：（1）检验以下假设：肌动蛋白索的长度、速度和结构是由微丝倒刺末端的动态相互作用控制的，其中微丝倒刺末端涉及formin、Bud 14-Kel 1-Kel 2复合物、加帽蛋白和Smy 1;和（3）检验人CLIP-170与mDia 1相互作用形成一种新的有倒钩末端追踪复合物的假设，该复合物在体外和体内支持超快肌动蛋白丝伸长。

 DESCRIPTION (provided by applicant): The goal of this research is to determine how the assembly dynamics and architecture of the actin cytoskeleton are controlled by formins and the cellular mechanisms regulating their activities. We are studying this question in budding yeast, where formins assemble actin cables of a characteristic length, architecture, and dynamics required for polarized cell growth. Further, we extend this work to mammalian formin regulation. The proposal focuses on several new multi-component mechanisms discovered during the previous funding cycle, which control formin-mediated actin nucleation, or the duration and speed of formin-mediated actin filament elongation events. The project combines genetics, live- cell imaging, biochemistry, and novel multi-wavelength single molecule TIRF microscopy. The Aims are: (1) Test the hypothesis that formin-mediated actin cable nucleation is spatially and temporally controlled by the combinatorial effects of Bud6, profilin, Tpm1, and Tpm2; (2) Test the hypothesis that actin cable length, velocity, and architecture are controlled by dynamic interplay at filament barbed ends involving formins, Bud14-Kel1-Kel2 complex, capping protein, and Smy1; and (3) Test the hypothesis that human CLIP-170 interacts with mDia1 to form a novel barbed end- tracking complex that supports ultrafast actin filament elongation in vitro and in vivo.