Wang Yuchen, Tang Yuting, Lin Chen, Zhang Junli, Mai Juntao, Jiang Jun, Gao Xiaoxiao, Li Yao, Zhao Guoping, Zhang Lu, Liu Jun
Department of Microbiology, School of Life Science, Fudan University, Shanghai 200090, China.
Guizhou institute of Biotechnology, Guiyang 550025, Guizhou, China.
iScience. 2021 Dec 8;25(1):103585. doi: 10.1016/j.isci.2021.103585. eCollection 2022 Jan 21.
The type VII secretion system (T7SS) of secretes three substrate classes: Esx, Esp, and PE/PPE proteins, that play important roles in bacterial physiology and host interaction. Five subtypes of T7SS, namely ESX-1 to ESX-5, are present in . ESX-4 is the progenitor of T7SS but its function is not understood. We investigated the ESX-4 system in . We show that ESX-4 of does not secrete its cognate substrates, EsxT and EsxU, under the conditions tested. Paradoxically, the deletion of , an essential component of ESX-4, resulted in elevated secretion of protein substrates of ESX-1 and ESX-5. Consequently, the Δ mutant was more efficient in inducing actin cytoskeleton rearrangement, which led to enhanced phagocytosis by macrophages. Our results reveal an intimate crosstalk between the progenitor of T7SS and its more recent duplication and expansion, and provide new insight into the evolution of T7SS in mycobacteria.
的VII型分泌系统（T7SS）分泌三类底物：Esx、Esp和PE/PPE蛋白，它们在细菌生理学和宿主相互作用中发挥重要作用。中存在T7SS的五个亚型，即ESX-1至ESX-5。ESX-4是T7SS的始祖，但对其功能尚不清楚。我们研究了中的ESX-4系统。我们发现，在测试条件下，的ESX-4不分泌其同源底物EsxT和EsxU。矛盾的是，ESX-4的一个必需组分的缺失导致ESX-1和ESX-5的蛋白质底物分泌增加。因此，Δ突变体在诱导肌动蛋白细胞骨架重排方面更有效，这导致巨噬细胞的吞噬作用增强。我们的结果揭示了T7SS始祖与其最近的复制和扩张之间的密切相互作用，并为分枝杆菌中T7SS的进化提供了新的见解。
