A repeat unit of Vibrio diarrheal T3S effector subverts cytoskeletal actin homeostasis via binding to interstrand region of actin filaments.
A repeat unit of Vibrio diarrheal T3S effector subverts cytoskeletal actin homeostasis via binding to interstrand region of actin filaments.
复制标题
DOI：
10.1038/srep10870
复制
发表时间：
2015-06-03
影响因子：
4.6
通讯作者：
Iida T
中科院分区：
文献类型：
--
作者：
Nishimura M;Fujii T;Hiyoshi H;Makino F;Inoue H;Motooka D;Kodama T;Ohkubo T;Kobayashi Y;Nakamura S;Namba K;Iida T
肠道病原菌副溶血性弧菌的一种新的细菌III型分泌效应物VopV，由于其与细胞骨架肌动蛋白的相互作用，已被确定为致病性的关键因素。VopV长重复区域中的一个重复单位，命名为VopVep1，起到肌动蛋白结合模块的作用。尽管它在发病机制中很重要，但效应器与肌动蛋白结合的方式以及随后对肌动蛋白动力学的影响仍不清楚。在这里，我们报告了VopVep1/肌动蛋白相互作用的分子基础。VopVep1在溶液中以非结构蛋白的形式存在，但能有效和特异地结合丝状肌动蛋白(F-肌动蛋白)而不是球状肌动蛋白(G-肌动蛋白)。F-肌动蛋白/VopVep1复合体通过电子冷冻显微镜和螺旋图像重建以9.6？分辨率直接可视化。密度图显示VopVep1在两条肌动蛋白链之间的结合部位，与双环七肽毒素鬼臼毒素的结合部位接近。与此观察一致的是，VopVep1单独阻止了F-肌动蛋白的解聚。总体而言，与已知的肌动蛋白结合蛋白相比，VopVep1显示出独特的特征，但与鬼臼毒素相对相似。针对肌动蛋白细丝的链间区域以稳定细丝结构为靶点的鬼臼毒素样行为可能是副溶血性弧菌致病的原因之一。
A novel bacterial type III secretion effector, VopV, from the enteric pathogen Vibrio parahaemolyticus has been identified as a key factor in pathogenicity due to its interaction with cytoskeletal actin. One of the repeat units in the long repetitive region of VopV, named VopVrep1, functions as an actin-binding module. Despite its importance in pathogenesis, the manner in which the effector binds to actin and the subsequent effects on actin dynamics remain unclear. Here, we report the molecular basis of the VopVrep1/actin interaction. VopVrep1 exists as an unstructured protein in solution but potently and specifically binds filamentous actin (F-actin) and not globular actin (G-actin). The F-actin/VopVrep1 complex was directly visualized at 9.6-Å resolution using electron cryomicroscopy (cryoEM) and helical image reconstitution. The density map revealed the binding site of VopVrep1 at the interface between two actin strands, which is close to the binding site of the bicyclic heptapeptide toxin phalloidin. Consistent with this observation, VopVrep1 alone prevented the depolymerization of F-actin. Overall, VopVrep1 demonstrated unique characteristics in comparison to known actin-binding proteins, but was relatively similar to phalloidin. The phalloidin-like behavior, targeting the interstrand region of actin filaments to stabilize the filament structure, likely contributes to the pathogenicity of V. parahaemolyticus.