Mechanistic Aspects of Actin Polymerization at WH2-proteins: Human Spir and VopF from V. cholerae in Comparison

WH2 蛋白肌动蛋白聚合的机制：人类 Spir 和来自霍乱弧菌的 VopF 的比较

• 批准号: 171084014
• 负责人: Professor Dr. Kornelius Zeth
• 金额: --
• 依托单位: Institute for Mathematics and Physics
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2010
• 资助国家: 德国
• 起止时间: 2009-12-31 至 2013-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/171084014?language=en
• 关键词: Mechanistic; Aspects; Actin; Polymerization; WH2

Initiation of actin nucleation and polymerization requires protein scaffolds of different types which allow for sequestration and orientation of free actin molecules. The Arp2/3 complex has been reported to polymerize branched actin filaments, while formin-like nucleators are known to form unbranched actin polymers at the barbed end. A third factor, Spir, has been described to initiate unbranched actin filaments from the pointed end by the occurrence of four subsequent WASP Homology 2 domains (WH2). Due to the localization of Spir at membrane surfaces, a possible function of this protein in vesicle transport within cells has been proposed. The Spir sequence comprises four domains, the KIND domain, the WH2 cluster, the Spir-box and the FYVE domain for membrane interaction. Attachment of Spir to membranes and initiation of actin polymerization processes involves a number of co-factors: actin monomers, formin, and possibly membrane-bound GTPases. To understand the regulation of nucleation and polymerization by Spir on a mechanistic basis we have started to map interactions by structure biology methods. Our first attempt was the determination of a complex structure between the Spir/KIND and the formin Spir interaction (FSI) module. More recently it turned out that also pathogenic bacteria use WH2- domain clusters in secreted effector proteins to manipulate the host cell cytoskeleton. We currently investigate the structure of VopF from Vibrio cholerae mimicking the WH2-scaffold of Spir proteins. Here we aim to understand the interference into the host cell pathways and to compare principles of actin filament formation on WH2 domain clusters in general.

肌动蛋白成核和聚合的启动需要不同类型的蛋白质支架，以允许游离肌动蛋白分子的隔离和定向。据报道，Arp2/3 复合物可聚合支化肌动蛋白丝，而已知类福明成核剂可在有刺末端形成无支化肌动蛋白聚合物。第三个因子 Spir 被描述为通过四个后续 WASP 同源 2 结构域 (WH2) 的出现从尖端启动不分支的肌动蛋白丝。由于 Spir 位于膜表面，因此有人提出该蛋白在细胞内囊泡运输中可能具有的功能。 Spir 序列包含四个结构域：KIND 结构域、WH2 簇、Spir-box 和用于膜相互作用的 FYVE 结构域。 Spir 与膜的附着和肌动蛋白聚合过程的启动涉及许多辅助因子：肌动蛋白单体、福尔明和可能的膜结合 GTP 酶。为了从机理上了解 Spir 对成核和聚合的调节，我们开始通过结构生物学方法绘制相互作用图谱。我们的第一次尝试是确定 Spir/KIND 和 formin Spir 相互作用 (FSI) 模块之间的复杂结构。最近发现，病原菌也利用分泌的效应蛋白中的 WH2 结构域簇来操纵宿主细胞的细胞骨架。我们目前研究霍乱弧菌中模拟 Spir 蛋白 WH2 支架的 VopF 结构。在这里，我们的目的是了解对宿主细胞途径的干扰，并比较 WH2 结构域簇上肌动蛋白丝形成的一般原理。