Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, VIC 3000, Australia.
Department of Microbial Pathogenesis, Boyer Center for Molecular Medicine, Yale University School of Medicine, New Haven CT 06510.
Proc Natl Acad Sci U S A. 2020 Mar 24;117(12):6801-6810. doi: 10.1073/pnas.1921344117. Epub 2020 Mar 9.
is an intracellular pathogen that replicates in a lysosome-like vacuole through activation of a Dot/Icm-type IVB secretion system and subsequent translocation of effectors that remodel the host cell. Here a genome-wide small interfering RNA screen and reporter assay were used to identify host proteins required for Dot/Icm effector translocation. Significant, and independently validated, hits demonstrated the importance of multiple protein families required for endocytic trafficking of the -containing vacuole to the lysosome. Further analysis demonstrated that the degradative activity of the lysosome created by proteases, such as TPP1, which are transported to the lysosome by receptors, such as M6PR and LRP1, are critical for virulence. Indeed, the PmrA/B regulon, responsible for transcriptional up-regulation of genes encoding the Dot/Icm apparatus and a subset of effectors, induced expression of a virulence-associated transcriptome in response to degradative products of the lysosome. Luciferase reporter strains, and subsequent RNA-sequencing analysis, demonstrated that particular amino acids activate the PmrA/B two-component system. This study has further enhanced our understanding of pathogenesis, the host-pathogen interactions that contribute to bacterial virulence, and the different environmental triggers pathogens can sense to facilitate virulence.
是一种细胞内病原体，通过激活 Dot/Icm 型 IVB 分泌系统并随后转运效应子来在类似于溶酶体的空泡中复制，这些效应子重塑宿主细胞。在这里，使用全基因组小干扰 RNA 筛选和报告基因测定来鉴定 Dot/Icm 效应子易位所需的宿主蛋白。显著的、独立验证的命中表明，多种蛋白家族对于含有 - 的空泡到溶酶体的内吞运输是必需的。进一步的分析表明，溶酶体的降解活性由蛋白酶（如 TPP1）创建，这些蛋白酶通过受体（如 M6PR 和 LRP1）被运输到溶酶体中，对于毒力是至关重要的。事实上，负责转录上调编码 Dot/Icm 装置和一部分效应子的基因的 PmrA/B 调节子，响应溶酶体的降解产物诱导与毒力相关的转录组的表达。荧光素酶报告株，以及随后的 RNA 测序分析，表明特定的氨基酸激活 PmrA/B 双组分系统。这项研究进一步增强了我们对 发病机制、导致细菌毒力的宿主-病原体相互作用以及病原体可以感知的不同环境触发因素以促进毒力的理解。
