Department of Biochemistry, Faculty of Science, University of Geneva, Sciences II, Geneva, Switzerland.
Section Parasitology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany.
PLoS Pathog. 2018 Dec 31;14(12):e1007501. doi: 10.1371/journal.ppat.1007501. eCollection 2018 Dec.
Phagocytic cells capture and kill most invader microbes within the bactericidal phagosome, but some pathogens subvert killing by damaging the compartment and escaping to the cytosol. To prevent the leakage of pathogen virulence and host defence factors, as well as bacteria escape, host cells have to contain and repair the membrane damage, or finally eliminate the cytosolic bacteria. All eukaryotic cells engage various repair mechanisms to ensure plasma membrane integrity and proper compartmentalization of organelles, including the Endosomal Sorting Complex Required for Transport (ESCRT) and autophagy machineries. We show that during infection of Dictyostelium discoideum with Mycobacterium marinum, the ESCRT-I component Tsg101, the ESCRT-III protein Snf7/Chmp4/Vps32 and the AAA-ATPase Vps4 are recruited to sites of damage at the Mycobacterium-containing vacuole. Interestingly, damage separately recruits the ESCRT and the autophagy machineries. In addition, the recruitment of Vps32 and Vps4 to repair sterile membrane damage depends on Tsg101 but appears independent of Ca2+. Finally, in absence of Tsg101, M. marinum accesses prematurely the cytosol, where the autophagy machinery restricts its growth. We propose that ESCRT has an evolutionary conserved function to repair small membrane damage and to contain intracellular pathogens in intact compartments.
吞噬细胞在杀菌吞噬体中捕获并杀死大多数入侵的微生物,但一些病原体通过破坏隔室并逃到细胞质中来逃避杀伤。为了防止病原体毒力和宿主防御因子的泄漏,以及细菌的逃逸,宿主细胞必须包含并修复膜损伤,或者最终消除细胞质中的细菌。所有真核细胞都采用各种修复机制来确保质膜完整性和细胞器的适当区室化,包括内体分选复合物必需的运输(ESCRT)和自噬机制。我们表明,在粘菌(Dictyostelium discoideum)感染海洋分枝杆菌(Mycobacterium marinum)期间,ESCRT-I 成分 Tsg101、ESCRT-III 蛋白 Snf7/Chmp4/Vps32 和 AAA-ATPase Vps4 被招募到含有分枝杆菌的液泡的损伤部位。有趣的是,损伤分别招募了 ESCRT 和自噬机制。此外,Vps32 和 Vps4 对修复无菌膜损伤的募集依赖于 Tsg101,但似乎独立于 Ca2+。最后,在没有 Tsg101 的情况下,海洋分枝杆菌过早进入细胞质,其中自噬机制限制了它的生长。我们提出 ESCRT 具有修复小膜损伤和将胞内病原体包含在完整隔室中的进化保守功能。