title: The phagosomal proteome in interferon-gamma-activated macrophages.
abstract: The ability of macrophages to clear pathogens and elicit a sustained immune response is regulated by various cytokines, including interferon-gamma (IFN-gamma). To investigate the molecular mechanisms by which IFN-gamma modulates phagosome functions, we profiled the changes in composition, abundance, and phosphorylation of phagosome proteins in resting and activated macrophages by using quantitative proteomics and bioinformatics approaches. We identified 2415 phagosome proteins together with 2975 unique phosphorylation sites with a high level of sensitivity. Using network analyses, we determined that IFN-gamma delays phagosomal acquisition of lysosomal hydrolases and peptidases for the gain of antigen presentation. Furthermore, this gain in antigen presentation is dependent on phagosomal networks of the actin cytoskeleton and vesicle-trafficking proteins, as well as Src kinases and calpain proteases. Major histocompatibility complex class I antigen-presentation assays validated the molecular participation of these networks in the enhanced capacity of IFN-gamma-activated macrophages to crosspresent exogenous antigens to CD8(+) T cells.
authors.affiliation: Department of Pathology and Cell Biology, Université de Montréal, Succ Centre-ville, Montréal, Québec, Canada.
authors.forename: Matthias
authors.initials: M
authors.lastname: Trost
authors.forename: Luc
authors.initials: L
authors.lastname: English
authors.forename: Sébastien
authors.initials: S
authors.lastname: Lemieux
authors.forename: Mathieu
authors.initials: M
authors.lastname: Courcelles
authors.forename: Michel
authors.initials: M
authors.lastname: Desjardins
authors.forename: Pierre
authors.initials: P
authors.lastname: Thibault
mesh_terms: D000818:Animals; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D002478:Cells, Cultured; D004591:Electrophoresis, Polyacrylamide Gel; D007371:Interferon-gamma / Q000378:metabolism* / Q000494:pharmacology; D008213:Lymphocyte Activation; D008264:Macrophages / Q000276:immunology*; D013058:Mass Spectrometry; D051379:Mice; D010588:Phagosomes / Q000187:drug effects / Q000276:immunology / Q000378:metabolism*; D010766:Phosphorylation; D010770:Phosphotransferases / Q000378:metabolism; D020543:Proteome / Q000276:immunology / Q000378:metabolism*; D040901:Proteomics; D015854:Up-Regulation
chemical_list: D020543:Proteome; D007371:Interferon-gamma; D010770:Phosphotransferases