title: Endoplasmic reticulum-mediated phagocytosis is a mechanism of entry into macrophages.
abstract: Phagocytosis is a key aspect of our innate ability to fight infectious diseases. In this study, we have found that fusion of the endoplasmic reticulum (ER) with the macrophage plasmalemma, underneath phagocytic cups, is a source of membrane for phagosome formation in macrophages. Successive waves of ER become associated with maturing phagosomes during phagolysosome biogenesis. Thus, the ER appears to possess unexpectedly pluripotent fusion properties. ER-mediated phagocytosis is regulated in part by phosphatidylinositol 3-kinase and used for the internalization of inert particles and intracellular pathogens, regardless of their final trafficking in the host. In neutrophils, where pathogens are rapidly killed, the ER is not used as a major source of membrane for phagocytosis. We propose that intracellular pathogens have evolved to adapt and exploit ER-mediated phagocytosis to avoid destruction in host cells.
authors.affiliation: Département de Pathologie et Biologie Cellulaire, Université de Montréal, Montréal, Québec, Canada.
authors.forename: Etienne
authors.initials: E
authors.lastname: Gagnon
authors.forename: Sophie
authors.initials: S
authors.lastname: Duclos
authors.forename: Christiane
authors.initials: C
authors.lastname: Rondeau
authors.forename: Eric
authors.initials: E
authors.lastname: Chevet
authors.forename: Pamela H
authors.initials: PH
authors.lastname: Cameron
authors.forename: Olivia
authors.initials: O
authors.lastname: Steele-Mortimer
authors.forename: Jacques
authors.initials: J
authors.lastname: Paiement
authors.forename: John J M
authors.initials: JJ
authors.lastname: Bergeron
authors.forename: Michel
authors.initials: M
authors.lastname: Desjardins
mesh_terms: D000818:Animals; D002135:Calcium-Binding Proteins / Q000378:metabolism; D037281:Calnexin; D002462:Cell Membrane / Q000502:physiology; D002478:Cells, Cultured; D004285:Dogs; D004721:Endoplasmic Reticulum / Q000378:metabolism / Q000502:physiology* / Q000648:ultrastructure; D007425:Intracellular Membranes / Q000737:chemistry / Q000502:physiology / Q000648:ultrastructure; D008264:Macrophages / Q000166:cytology / Q000502:physiology*; D010587:Phagocytosis / Q000502:physiology*; D010588:Phagosomes / Q000378:metabolism / Q000502:physiology* / Q000648:ultrastructure; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D021381:Protein Transport / Q000502:physiology; D006180:Proton-Translocating ATPases / Q000378:metabolism; D012756:Sheep
chemical_list: D002135:Calcium-Binding Proteins; D037281:Calnexin; D019869:Phosphatidylinositol 3-Kinases; D006180:Proton-Translocating ATPases