塞普汀
志贺氏菌
自噬
生物
细胞生物学
液泡
胞浆
微生物学
细胞
细胞分裂
生物化学
胞质分裂
大肠杆菌
细胞凋亡
细胞质
酶
基因
作者
Damián Lobato‐Márquez,José Javier Conesa,Ana Teresa López-Jiménez,Michael E. Divine,Jonathan N. Pruneda,Serge Mostowy
摘要
ABSTRACT During host cell invasion, Shigella escapes to the cytosol and polymerizes actin for cell-to-cell spread. To restrict cell-to-cell spread, host cells employ cell-autonomous immune responses including antibacterial autophagy and septin cage entrapment. How septins interact with the autophagy process to target Shigella for destruction is poorly understood. Here, we employed a correlative light and cryo-soft X-ray tomography (cryo-SXT) pipeline to study Shigella septin cage entrapment in its near-native state. Quantitative cryo-SXT showed that Shigella fragments mitochondria and enabled visualization of X-ray-dense structures (∼30 nm resolution) surrounding Shigella entrapped in septin cages. Using Airyscan confocal microscopy, we observed lysine 63 (K63)-linked ubiquitin chains decorating septin-cage-entrapped Shigella. Remarkably, septins and K63 chains are present in separate bacterial microdomains, indicating they are recruited separately during antibacterial autophagy. Cryo-SXT and live-cell imaging revealed an interaction between septins and LC3B-positive membranes during autophagy of Shigella. Together, these findings demonstrate how septin-caged Shigella are targeted for autophagy and provide fundamental insights into autophagy–cytoskeleton interactions.
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