TLR signals induce phagosomal MHC-I delivery from the endosomal recycling compartment to allow cross-presentation

Priyanka Nair-Gupta, Alessia Baccarini, Navpreet Tung, Fabian Seyffer, Oliver Florey, Yunjie Huang, Meenakshi Banerjee, Michael Overholtzer, Paul A. Roche, Robert Tampé, Brian D. Brown, Derk Amsen, Sidney W. Whiteheart, J. Magarian Blander

Research output: Contribution to journalArticleAcademicpeer-review

249 Citations (Scopus)

Abstract

Adaptation of the endoplasmic reticulum (ER) pathway for MHC class I (MHC-I) presentation in dendritic cells enables cross-presentation of peptides derived from phagocytosed microbes, infected cells, or tumor cells to CD8 T cells. How these peptides intersect with MHC-I molecules remains poorly understood. Here, we show that MHC-I selectively accumulate within phagosomes carrying microbial components, which engage Toll-like receptor (TLR) signaling. Although cross-presentation requires Sec22b-mediated phagosomal recruitment of the peptide loading complex from the ER-Golgi intermediate compartment (ERGIC), this step is independent of TLR signaling and does not deliver MHC-I. Instead, MHC-I are recruited from an endosomal recycling compartment (ERC), which is marked by Rab11a, VAMP3/cellubrevin, and VAMP8/endobrevin and holds large reserves of MHC-I. While Rab11a activity stocks ERC stores with MHC-I, MyD88-dependent TLR signals drive IκB-kinase (IKK)2-mediated phosphorylation of phagosome-associated SNAP23. Phospho-SNAP23 stabilizes SNARE complexes orchestrating ERC-phagosome fusion, enrichment of phagosomes with ERC-derived MHC-I, and subsequent cross-presentation during infection
Original languageEnglish
Pages (from-to)506-521
JournalCell
Volume158
Issue number3
DOIs
Publication statusPublished - 2014

Cite this