Bacterial secretion system skews the fate of Legionella-containing vacuoles towards LC3-associated phagocytosis.
The evolutionarily conserved processes of endosome-lysosome maturation and macroautophagy are established mechanisms that limit survival of intracellular bacteria. Similarly, another emerging mechanism is LC3-associated phagocytosis (LAP). Here we report that an intracellular vacuolar pathogen, Legionella dumoffii, is specifically targeted by LAP over classical endocytic maturation and macroautophagy pathways. Upon infection, the majority of L. dumoffii resides in ER-like vacuoles and replicate within this niche, which involves inhibition of classical endosomal maturation. The establishment of the replicative niche requires the bacterial Dot/Icm type IV secretion system (T4SS). Intriguingly, the remaining subset of L. dumoffii transiently acquires LC3 to L. dumoffii-containing vacuoles in a Dot/Icm T4SS-dependent manner. The LC3-decorated vacuoles are bound by an apparently undamaged single membrane, and fail to associate with the molecules implicated in selective autophagy, such as ubiquitin or adaptors. The process requires toll-like receptor 2, Rubicon, diacylglycerol signaling and downstream NADPH oxidases, whereas ULK1 kinase is dispensable. Together, we have discovered an intracellular pathogen, the survival of which in infected cells is limited predominantly by LAP. The results suggest that L. dumoffii is a valuable model organism for examining the mechanistic details of LAP, particularly induced by bacterial infection.
Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
Andree
A
Hubber
Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
Tomoko
T
Kubori
Laboratory of Malaria Immunology, Immunology Frontier Research Centre, Osaka University, 3-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
Cevayir
C
Coban
Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Rinku Ohrai Kita 1-58, Izumisano, Osaka 598-8531, Japan.
Takeshi
T
Matsuzawa
Department of Bacteriology I, National Institute of Infectious Diseases, Toyama 1-23-1, Shinjuku-ku, Tokyo 162-8640, Japan.
Michinaga
M
Ogawa
Department of Genetics, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan.
Tsuyoshi
T
Kawabata
Department of Genetics, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan.
Tamotsu
T
Yoshimori
Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
Hiroki
H
Nagai
D000818:Animals; D001343:Autophagy; D000071189:Autophagy-Related Protein-1 Homolog / Q000378:metabolism; D058947:Bacterial Secretion Systems; D015415:Biomarkers / Q000378:metabolism; D004075:Diglycerides / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000378:metabolism; D011992:Endosomes / Q000378:metabolism; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D042541:Intracellular Space / Q000382:microbiology; D007875:Legionella / Q000378:metabolism* / Q000648:ultrastructure; D007876:Legionellosis / Q000201:enzymology / Q000473:pathology; D051379:Mice; D050296:Microbial Viability; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D019255:NADPH Oxidases / Q000378:metabolism; D010587:Phagocytosis; D000067996:RAW 264.7 Cells; D015398:Signal Transduction; D051195:Toll-Like Receptor 2 / Q000378:metabolism; D025801:Ubiquitin / Q000378:metabolism; D014617:Vacuoles / Q000378:metabolism* / Q000648:ultrastructure
D058947:Bacterial Secretion Systems; D015415:Biomarkers; D004075:Diglycerides; C480860:Map1lc3b protein, mouse; D008869:Microtubule-Associated Proteins; D051195:Toll-Like Receptor 2; D025801:Ubiquitin; D019255:NADPH Oxidases; D000071189:Autophagy-Related Protein-1 Homolog; C112444:Ulk1 protein, mouse