Project 1: Spectroscopic assays to characterize conform changes in Arp2/3 complx

肌动蛋白细胞骨架的组装动力学对于大多数形态发生过程至关重要， 发生在真核生物的细胞和生物体水平。因此，肌动蛋白动力学的缺陷 与多种人类疾病有关。然而，我们对 肌动蛋白在不同生理过程中的调节方式仍然有限， 肌动蛋白细胞骨架系统的复杂性和动态性质。Arp 2/3复合物被认为是一种 肌动蛋白丝成核的主要关键因素和分支树突状网络的形成， 运动细胞的前缘。Arp 2/3复合物在这些过程中的作用只能通过 通过研究Arp 2/3介导的肌动蛋白成核和分支中的关键分子步骤， 阵在这个项目中，我们的目标是通过以下方式了解详细的结构机制： Arp 2/3复合物介导肌动蛋白分支连接的形成，Arp 2/3复合物的作用 复杂的脊椎动物细胞运动。我们组建了一个高度协同的私家侦探团队， 通过合作努力实现这些目标。本分项工程 （Jummannlab）将为开发和应用一套多样化的计算工具做出贡献 用于结构状态和分布模式的重建、分析和建模。使用这些 工具，我们将联合收割机信息从各种数据源产生的所有成员的计划 获得（一）分支形成过程中间体和 完全组装的分支本身;（ii）一个动态的，能量自洽的，结构模型的 从Arp 2/3复合物的失活状态到完全组装的分支的转变途径 树突状网络，和（iii）不同细胞类型之间和野生型之间的结构差异 通过Arp 2/3-复合物的多维和动态表征， 和肌动蛋白丝在活的真核细胞中的分布模式。

The assembly dynamics of the actin cytoskeleton is crucial for most morphogenetic processes that occur at both cellular and organism levels in eukaryotes. As a consequence, defects in actin dynamics and organization have been implicated in a variety of human diseases. However, our understanding of how actin is regulated in different physiological processes remains limited due to the extraordinary complexity and dynamic nature of the actin cytoskeletal system. The Arp2/3 complex is thought to be a major key element of actin filament nucleation and the formation of branched dendritic networks at the leading edge of motile cells. The role of Arp2/3 complex in these processes can only be understood through studies of the key molecular steps in the Arp2/3-mediated actin nucleation and branch formation. In this Program Project we aim at understanding the detailed structural mechanisms by which the Arp2/3 complex mediates the formation of actin branch junctions and the role of the Arp2/3 complex in vertebrate cell motility. We have assembled a highly synergistic team of Pis with complimentary expertise to achieve these goals through collaborative efforts. This sub-project (Volkmann lab) will contribute the development and application of a diverse set of computational tools for the reconstruction, analysis, and modeling of structural states and distribution patterns. Using these tools we will combine information from various data sources generated by all members of the Program Project to obtain (i) high-resolution models of the intermediates of the branch formation process and of the fully assembled branch itself; (ii) a dynamic, energetically self-consistent, structural model of the transition pathway from the inactive state of the Arp2/3 complex to the fully assembled branch in the dendritic network, and (iii) structural differences between different cell types and between wild-type cells and defective mutants by multi-dimensional and dynamical characterization of Arp2/3-complex and actin-filament distribution patterns in living eukaryotic cells.