1. A type III effector antagonizes death receptor signalling during bacterial gut infection
- Author
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Pearson, Jaclyn S., Giogha, Cristina, Ong, Sze Ying, Kennedy, Catherine L., Kelly, Michelle, Robinson, Keith S., Lung, Tania Wong Fok, Mansell, Ashley, Riedmaier, Patrice, Oates, Clare V.L., Zaid, Ali, Muhlen, Sabrina, Crepin, Valerie F., Marches, Olivier, Ang, Ching-Seng, Williamson, Nicholas A., O'Reilly, Lorraine A., Bankovacki, Aleksandra, Nachbur, Ueli, Infusini, Giuseppe, Webb, Andrew I., Silke, John, Strasser, Andreas, Frankel, Gad, and Hartland, Elizabeth L.
- Subjects
Stomach diseases -- Physiological aspects ,Bacterial infections -- Research ,Microbiology -- Research ,Cell receptors -- Physiological aspects ,Pathogenic microorganisms -- Physiological aspects ,Environmental issues ,Science and technology ,Zoology and wildlife conservation - Abstract
Successful infection by enteric bacterial pathogens depends on the ability of the bacteria to colonize the gut, replicate in host tissues and disseminate to other hosts. Pathogens such as Salmonella, Shigella and enteropathogenic and enterohaemorrhagic (EPEC and EHEC, respectively) Escherichia coli use a type III secretion system (T3SS) to deliver virulence effector proteins into host cells during infection that promote colonization and interfere with antimicrobial host responses (1-3). Here we report that the T3SS effector NleB1 from EPEC binds to host cell death-domain-containing proteins and thereby inhibits death receptor signalling. Protein interaction studies identified FADD, TRADD and RIPK1 as binding partners of NleB1. NleB1 expressed ectopically or injected by the bacterial T3SS prevented Fas ligand or TNF-induced formation of the canonical death-inducing signalling complex (DISC) and proteolytic activation of caspase-8, an essential step in death-receptor-induced apoptosis. This inhibition depended on the N-acetylglucosamine transferase activity of NleB1, which specifically modified Arg 117 in the death domain of FADD. The importance of the death receptor apoptotic pathway to host defence was demonstrated using mice deficient in the FAS signalling pathway, which showed delayed clearance of the EPEC-like mouse pathogen Citrobacter rodentium and reversion to virulence of an nleB mutant. The activity of NleB suggests that EPEC and other attaching and effacing pathogens antagonize death-receptor-induced apoptosis of infected cells, thereby blocking a major antimicrobial host response., Members of the death receptor family such as FAS and TNFR1 contain an intracellular death domain and require caspase-8 for the activation of effector caspases and consequent cell death by [...]
- Published
- 2013