The Salmonella Deubiquitinase SseL Inhibits Selective Autophagy of Cytosolic Aggregates

PLoS Pathogens

Martin Sachse¹  Mair Thomas²  David W. Holden²  Francisco S. Mesquita²  Rita Figueira²  António J. M. Santos² 

[1] Imagopole, Institut Pasteur, Paris, France;Section of Microbiology, Centre for Molecular Microbiology and Infection, Imperial College London, London, United Kingdom

关键词: Macrophages;    Salmonellosis;    Salmonella typhimurium;    Autophagic cell death;    HeLa cells;    Salmonella;    Bacterial genetics;    Intracellular pathogens;   

DOI  :  10.1371/journal.ppat.1002743

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

Cell stress and infection promote the formation of ubiquitinated aggregates in both non-immune and immune cells. These structures are recognised by the autophagy receptor p62/sequestosome 1 and are substrates for selective autophagy. The intracellular growth of Salmonella enterica occurs in a membranous compartment, the Salmonella-containing vacuole (SCV), and is dependent on effectors translocated to the host cytoplasm by the Salmonella pathogenicity island-2 (SPI-2) encoded type III secretion system (T3SS). Here, we show that bacterial replication is accompanied by the formation of ubiquitinated structures in infected cells. Analysis of bacterial strains carrying mutations in genes encoding SPI-2 T3SS effectors revealed that in epithelial cells, formation of these ubiquitinated structures is dependent on SPI-2 T3SS effector translocation, but is counteracted by the SPI-2 T3SS deubiquitinase SseL. In macrophages, both SPI-2 T3SS-dependent aggregates and aggresome-like induced structures (ALIS) are deubiquitinated by SseL. In the absence of SseL activity, ubiquitinated structures are recognized by the autophagy receptor p62, which recruits LC3 and targets them for autophagic degradation. We found that SseL activity lowers autophagic flux and favours intracellular Salmonella replication. Our data therefore show that there is a host selective autophagy response to intracellular Salmonella infection, which is counteracted by the deubiquitinase SseL.

【 授权许可】

CC BY