Department of Microbiology, Graduate School of Medicine, Kyoto University, Yoshida-Konoe-cho, Sakyo-ku, Kyoto, 606-8501, Japan.
Medical Research Support Center, Graduate School of Medicine, Kyoto University, Yoshida-Konoe-cho, Sakyo-ku, Kyoto, 606-8501, Japan.
Nat Commun. 2023 Oct 6;14(1):6230. doi: 10.1038/s41467-023-42039-2.
Xenophagy, a type of selective autophagy, is a bactericidal membrane trafficking that targets cytosolic bacterial pathogens, but the membrane homeostatic system to cope with bacterial infection in xenophagy is not known. Here, we show that the endosomal sorting complexes required for transport (ESCRT) machinery is needed to maintain homeostasis of xenophagolysosomes damaged by a bacterial toxin, which is regulated through the TOM1L2-Rab41 pathway that recruits AAA-ATPase VPS4. We screened Rab GTPases and identified Rab41 as critical for maintaining the acidification of xenophagolysosomes. Confocal microscopy revealed that ESCRT components were recruited to the entire xenophagolysosome, and this recruitment was inhibited by intrabody expression against bacterial cytolysin, indicating that ESCRT targets xenophagolysosomes in response to a bacterial toxin. Rab41 translocates to damaged autophagic membranes via adaptor protein TOM1L2 and recruits VPS4 to complete ESCRT-mediated membrane repair in a unique GTPase-independent manner. Finally, we demonstrate that the TOM1L2-Rab41 pathway-mediated ESCRT is critical for the efficient clearance of bacteria through xenophagy.
异噬作用是一种选择性自噬,是一种靶向细胞质细菌病原体的杀菌膜运输方式,但异噬作用中应对细菌感染的膜稳态系统尚不清楚。在这里,我们表明,内体分选复合物必需运输(ESCRT)机制对于维持被细菌毒素破坏的异噬溶酶体的稳态是必需的,这是通过招募 AAA-ATPase VPS4 的 TOM1L2-Rab41 途径来调节的。我们筛选了 Rab GTPases,并鉴定出 Rab41 对于维持异噬溶酶体的酸化是关键的。共聚焦显微镜显示,ESCRT 成分被招募到整个异噬溶酶体,而这种招募被针对细菌细胞毒素的内体表达所抑制,表明 ESCRT 针对细菌毒素靶向异噬溶酶体。Rab41 通过衔接蛋白 TOM1L2 易位到受损的自噬膜,并以独特的 GTPase 非依赖性方式招募 VPS4 完成 ESCRT 介导的膜修复。最后,我们证明了 TOM1L2-Rab41 途径介导的 ESCRT 对于通过异噬作用有效清除细菌是至关重要的。