title: Chaperone BAG6 is dispensable for MHC class I antigen processing and presentation.
abstract: Antigen processing for direct presentation on MHC class I molecules is a multistep process requiring the concerted activity of several cellular complexes. The essential steps at the beginning of this pathway, namely protein synthesis at the ribosome and degradation via the proteasome, have been known for years. Nevertheless, there is a considerable lack of factors identified to function between protein synthesis and degradation during antigen processing. Here, we analyzed the impact of the chaperone BAG6 on MHC class I cell surface expression and presentation of virus-derived peptides. Although an essential role of BAG6 in antigen processing has been proposed previously, we found BAG6 to be dispensable in this pathway. Still, interaction of BAG6 and the model antigen tyrosinase was enhanced during proteasome inhibition pointing towards a role of BAG6 in antigen degradation. Redundant chaperone pathways potentially mask the contribution of BAG6 to antigen processing and presentation.
authors.affiliation: Division of Immunology, Department of Biology, University of Konstanz, D-78457 Konstanz, Germany.
authors.forename: Annegret
authors.initials: A
authors.lastname: Bitzer
authors.affiliation: Division of Immunology, Department of Biology, University of Konstanz, D-78457 Konstanz, Germany; Biotechnology Institute Thurgau (BITg) at the University of Konstanz, CH-8280 Kreuzlingen, Switzerland.
authors.forename: Michael
authors.initials: M
authors.lastname: Basler
authors.affiliation: Division of Immunology, Department of Biology, University of Konstanz, D-78457 Konstanz, Germany; Biotechnology Institute Thurgau (BITg) at the University of Konstanz, CH-8280 Kreuzlingen, Switzerland. Electronic address: Marcus.Groettrup@uni-konstanz.de.
authors.forename: Marcus
authors.initials: M
authors.lastname: Groettrup
mesh_terms: D000818:Animals; D017951:Antigen Presentation / Q000276:immunology*; D015153:Blotting, Western; D005434:Flow Cytometry; D015395:Histocompatibility Antigens Class I / Q000276:immunology*; D047468:Immunoprecipitation; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D018832:Molecular Chaperones / Q000276:immunology*; D009687:Nuclear Proteins / Q000276:immunology*; D060888:Real-Time Polymerase Chain Reaction; D014162:Transfection
chemical_list: C092009:BAG6 protein, human; C484266:Bag6 protein, mouse; D015395:Histocompatibility Antigens Class I; D018832:Molecular Chaperones; D009687:Nuclear Proteins
keywords: Antigen presentation; Antigen processing; BAG6; DRiPs; MHC class I