Department of Pathology, University of Cambridge, Cambridge CB2 1TN, United Kingdom.
Department of Biomedical Science, University of Sheffield, Sheffield S10 2TN, United Kingdom.
Proc Natl Acad Sci U S A. 2017 Apr 11;114(15):3915-3920. doi: 10.1073/pnas.1616418114. Epub 2017 Mar 27.
To establish infections, injects virulence effectors that hijack the host actin cytoskeleton and phosphoinositide signaling to drive pathogen invasion. How effectors reprogram the cytoskeleton network remains unclear. By reconstituting the activities of the effector SopE, we recapitulated Rho GTPase-driven actin polymerization at model phospholipid membrane bilayers in cell-free extracts and identified the network of Rho-recruited cytoskeleton proteins. Knockdown of network components revealed a key role for myosin VI (MYO6) in invasion. SopE triggered MYO6 localization to invasion foci, and SopE-mediated activation of PAK recruited MYO6 to actin-rich membranes. We show that the virulence effector SopB requires MYO6 to regulate the localization of PIP3 and PI(3)P phosphoinositides and Akt activation. SopE and SopB target MYO6 to coordinate phosphoinositide production at invasion foci, facilitating the recruitment of cytoskeleton adaptor proteins to mediate pathogen uptake.
为了建立感染，细菌会注入毒力效应器，这些效应器劫持宿主肌动球蛋白细胞骨架和磷酸肌醇信号转导，以驱动病原体入侵。效应器如何重新编程细胞骨架网络尚不清楚。通过重新构建效应子 SopE 的活性，我们在无细胞提取物中的模型磷脂双层膜上重新生成了 Rho GTPase 驱动的肌动球蛋白聚合，并鉴定了 Rho 募集的细胞骨架蛋白网络。网络成分的敲低揭示了肌球蛋白 VI (MYO6) 在入侵中的关键作用。SopE 触发 MYO6 定位于入侵焦点，SopE 介导的 PAK 激活将 MYO6 募集到富含肌动蛋白的膜上。我们表明，毒力效应子 SopB 需要 MYO6 来调节 PIP3 和 PI(3)P 磷酸肌醇的定位和 Akt 的激活。SopE 和 SopB 将 MYO6 靶向入侵焦点，协调磷酸肌醇的产生，促进细胞骨架衔接蛋白的募集，以介导病原体摄取。
