RESUMO
A hallmark of macroautophagy is the covalent lipidation of LC3 and insertion into the double-membrane phagophore, which is driven by the ATG16L1/ATG5-ATG12 complex. In contrast, non-canonical autophagy is a pathway through which LC3 is lipidated and inserted into single membranes, particularly endolysosomal vacuoles during cell engulfment events such as LC3-associated phagocytosis. Factors controlling the targeting of ATG16L1 to phagophores are dispensable for non-canonical autophagy, for which the mechanism of ATG16L1 recruitment is unknown. Here we show that the WD repeat-containing C-terminal domain (WD40 CTD) of ATG16L1 is essential for LC3 recruitment to endolysosomal membranes during non-canonical autophagy, but dispensable for canonical autophagy. Using this strategy to inhibit non-canonical autophagy specifically, we show a reduction of MHC class II antigen presentation in dendritic cells from mice lacking the WD40 CTD Further, we demonstrate activation of non-canonical autophagy dependent on the WD40 CTD during influenza A virus infection. This suggests dependence on WD40 CTD distinguishes between macroautophagy and non-canonical use of autophagy machinery.
Assuntos
Proteínas Relacionadas à Autofagia/metabolismo , Autofagia , Proteínas de Transporte/fisiologia , Membranas Intracelulares/metabolismo , Lipídeos de Membrana/metabolismo , Proteínas Associadas aos Microtúbulos/metabolismo , Repetições WD40 , Animais , Apresentação de Antígeno , Proteínas Relacionadas à Autofagia/genética , Células Cultivadas , Classe III de Fosfatidilinositol 3-Quinases/genética , Classe III de Fosfatidilinositol 3-Quinases/metabolismo , Células Dendríticas/metabolismo , Endossomos/metabolismo , Feminino , Humanos , Vírus da Influenza A/isolamento & purificação , Influenza Humana/metabolismo , Influenza Humana/patologia , Influenza Humana/virologia , Lisossomos/metabolismo , Camundongos , Camundongos Knockout , Proteínas Associadas aos Microtúbulos/genéticaRESUMO
Our intestinal microbiota harbors a diverse microbial community, often containing opportunistic bacteria with virulence potential. However, mutualistic host-microbial interactions prevent disease by opportunistic pathogens through poorly understood mechanisms. We show that the epithelial interleukin-22 receptor IL-22RA1 protects against lethal Citrobacter rodentium infection and chemical-induced colitis by promoting colonization resistance against an intestinal opportunistic bacterium, Enterococcus faecalis. Susceptibility of Il22ra1(-/-) mice to C. rodentium was associated with preferential expansion and epithelial translocation of pathogenic E. faecalis during severe microbial dysbiosis and was ameloriated with antibiotics active against E. faecalis. RNA sequencing analyses of primary colonic organoids showed that IL-22RA1 signaling promotes intestinal fucosylation via induction of the fucosyltransferase Fut2. Additionally, administration of fucosylated oligosaccharides to C. rodentium-challenged Il22ra1(-/-) mice attenuated infection and promoted E. faecalis colonization resistance by restoring the diversity of anaerobic commensal symbionts. These results support a model whereby IL-22RA1 enhances host-microbiota mutualism to limit detrimental overcolonization by opportunistic pathogens.
