Structure and Function of Arp 2/3 Complex

描述（由申请人提供）：本项目的长期目标是了解允许Arp 2/3复合物在内吞作用和细胞运动过程中控制肌动蛋白丝组装的分子机制。Arp 2/3复合物的作用机制非常复杂，需要团队的努力。我们的四个地理上分散的实验室结合了X射线晶体学，电子显微镜，图像处理和分子生物学，以解决技术上具有挑战性的问题。他正在进行的合作的结构见解将提供有关反应机制的重要线索，也有助于设计实验来测量动力学和热力学常数，并研究活细胞中的肌动蛋白组装。项目1（Pollard）提出了生物化学和X射线晶体学实验的组合，以获得关于Arp 2/3复合物的构象变化和大分子相互作用的详细结构信息。项目2（Li）提出了结合成核促进因子与纯化的Arp 2/3复合物的相互作用的生物物理研究和缺乏Arp 2/3复合物亚基的小鼠细胞的显微镜分析。项目3（Hanein）提出了纯化的Arp 2/3复合物、肌动蛋白丝分支和具有和不具有功能性Arp 2/3复合物的小鼠细胞中的肌动蛋白网络的电子显微镜。项目4（Eschmann）提出了计算方法，以从项目1和2的光谱实验以及项目3的电子显微照片中提取最大量的信息。

DESCRIPTION (provided by applicant): The long-term goal of this program project is to understand the molecular mechanisms that allow Arp2/3 complex to control actin filament assembly during endocytosis and cellular motility. The mechanism of action of Arp2/3 complex is so complicated that a team effort is required. Our group of four geographically dispersed laboratories combines x-ray crystallography, electron microscopy, image processing and molecular biology to address technically challenging questions. Structural insights from his ongoing collaboration will provide important clues about reaction mechanisms and also help to design experiments to measure kinetic and thermodynamic constants and to study actin assembly in live cells. Project 1 (Pollard) proposes a combination of biochemical and x-ray crystallographic experiments to obtain detailed structural information regarding conformational changes and macromolecular interactions of Arp2/3 complex. Project 2 (Li) proposes a combination of biophysical studies on interaction's of nucleation promoting factors with purified Arp2/3 complex and microscopic analysis of mouse cells lacking subunits of Arp2/3 complex. Project 3 (Hanein) proposes electron microscopy of purified Arp2/3 complex, actin filament branches and of actin networks in mouse cells with and without functional Arp2/3 complex. Project 4 (Volkmann) proposes computational methods to extract the maximal amount of information from spectroscopy experiments in projects 1 and 2 and the electron micrographs from project 3.