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A proteasome-dependent, TAP-independent pathway for cross-presentation of phagocytosed antigen.

ABSTRACT: Major histocompatibility complex (MHC) class I cross-presentation is thought to involve two pathways, one of which depends on both the TAP transporters and the proteasome and the other on neither. We found that preincubation of TAP-deficient dendritic cells at low temperature increases the density of MHC class I at the surface and fully restores cross-presentation of phagocytosed antigen, but not of soluble antigen internalized through receptors. Restoration of cross-presentation by TAP-deficient cells requires antigen degradation by the proteasome. Thus, TAP might mainly be required for recycling cell surface class I molecules during cross-presentation of phagocytosed antigens. Furthermore, phagosomes-but not endosomes-seem to have a TAP-independent mechanism to import peptides generated by cytosolic proteasome complexes.

SUBMITTER: Merzougui N

PROVIDER: S-EPMC3245693 | biostudies-other | 2011 Dec

REPOSITORIES: biostudies-other

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A proteasome-dependent, TAP-independent pathway for cross-presentation of phagocytosed antigen.

Merzougui Nawel N Kratzer Roland R Saveanu Loredana L van Endert Peter P

EMBO reports 20111201 12

Major histocompatibility complex (MHC) class I cross-presentation is thought to involve two pathways, one of which depends on both the TAP transporters and the proteasome and the other on neither. We found that preincubation of TAP-deficient dendritic cells at low temperature increases the density of MHC class I at the surface and fully restores cross-presentation of phagocytosed antigen, but not of soluble antigen internalized through receptors. Restoration of cross-presentation by TAP-deficien ...[more]

PMID: 22037009

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