Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205, USA.
Department of Pathology, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
J Cell Sci. 2023 Feb 15;136(4). doi: 10.1242/jcs.260159. Epub 2023 Feb 22.
Intracellular pathogens exploit cellular resources through host cell manipulation. Within its nonfusogenic parasitophorous vacuole (PV), Toxoplasma gondii targets host nutrient-filled organelles and sequesters them into the PV through deep invaginations of the PV membrane (PVM) that ultimately detach from this membrane. Some of these invaginations are generated by an intravacuolar network (IVN) of parasite-derived tubules attached to the PVM. Here, we examined the usurpation of host ESCRT-III and Vps4A by the parasite to create PVM buds and vesicles. CHMP4B associated with the PVM/IVN, and dominant-negative (DN) CHMP4B formed many long PVM invaginations containing CHMP4B filaments. These invaginations were shorter in IVN-deficient parasites, suggesting cooperation between the IVN and ESCRT. In infected cells expressing Vps4A-DN, enlarged intra-PV structures containing host endolysosomes accumulated, reflecting defects in PVM scission. Parasite mutants lacking T. gondii (Tg)GRA14 or TgGRA64, which interact with ESCRT, reduced CHMP4B-DN-induced PVM invaginations and intra-PV host organelles, with greater defects in a double knockout, revealing the exploitation of ESCRT to scavenge host organelles by Toxoplasma.
细胞内病原体通过操纵宿主细胞来利用细胞资源。在其非融合的寄生质膜空泡（PV）中，刚地弓形虫靶向宿主充满营养的细胞器，并通过 PV 膜（PVM）的深内陷将它们隔离到 PV 中，这些内陷最终与该膜分离。这些内陷中的一些是由附着在 PVM 上的寄生虫衍生小管组成的腔内网络（IVN）产生的。在这里，我们研究了寄生虫对宿主 ESCRT-III 和 Vps4A 的篡夺，以创建 PVM 芽和囊泡。CHMP4B 与 PVM/IVN 相关联，显性失活（DN）CHMP4B 形成了许多含有 CHMP4B 丝的长 PVM 内陷。在缺乏 IVN 的寄生虫中，这些内陷更短，这表明 IVN 和 ESCRT 之间存在合作。在表达 Vps4A-DN 的感染细胞中，含有宿主内溶酶体的 PV 内扩大结构积累，反映出 PVM 分裂的缺陷。缺乏 T. gondii (Tg)GRA14 或 TgGRA64 的寄生虫突变体，这些蛋白与 ESCRT 相互作用，减少了 CHMP4B-DN 诱导的 PVM 内陷和 PV 内的宿主细胞器，在双敲除突变体中缺陷更大，表明刚地弓形虫利用 ESCRT 来清除宿主细胞器。
