title: The protein tyrosine kinase Hck is located on lysosomal vesicles that are physically and functionally distinct from CD63-positive lysosomes in human macrophages.
abstract: In macrophages, lysosomes are suspected to have a heterogenous population of vesicles. This study was thus undertaken to identify and to characterize lysosomal compartments in human macrophages. Hck is a Src-family tyrosine kinase associated with secretory lysosomes in neutrophils and with cytoplasmic vesicles in macrophages that fuse with phagosomes. We identified these Hck-positive vesicles and compared them to CD63-positive, M6PR-negative vesicles known as classical lysosomes. Hck vesicles exhibited lysosomal features. Indeed, Hck-positive vesicles could be loaded with rhodamine-dextran, which has been shown to accumulate in lysosomal compartments. Hck was delivered to zymosan-containing phagosomes at a late stage of the maturation process, which occurs after the fusion with CD63-positive lysosomes. Finally, when mycobacteria were used to prevent phagolysosome biogenesis, Hck was not recruited to phagosomes. Moreover, Hck lysosomes were physically and functionally distinct from CD63-lysosomes. For instance, sucrose induced swelling of CD63-lysosomes without affecting Hck-positive ones. Only CD63-lysosomes fused with phagosomes in a microtubule-dependent manner. Entry of particles through the mannose receptor and Fcgamma receptors drove the phagosome towards a fusion with CD63-lysosomes, whereas only Fcgamma receptors induced the mobilisation of Hck-lysosomes. This study provides further evidence for the existence of sub-populations of lysosomes in macrophages: one stained by CD63 and another one characterized by the presence of Hck. Therefore, Hck represents a new tool to study the fusion dynamics of lysosomal compartments and their subversion by several intracellular pathogens.
authors.affiliation: Institut de Pharmacologie et de Biologie Structurale, Centre National de la Recherche Scientifique UMR 5089, 205 Route de Narbonne, 31077 Toulouse, France. astarie@ipbs
authors.forename: Catherine
authors.initials: C
authors.lastname: Astarie-Dequeker
authors.forename: Sébastien
authors.initials: S
authors.lastname: Carreno
authors.forename: Céline
authors.initials: C
authors.lastname: Cougoule
authors.forename: Isabelle
authors.initials: I
authors.lastname: Maridonneau-Parini
mesh_terms: D015703:Antigens, CD / Q000032:analysis* / Q000276:immunology; D005455:Fluorescent Antibody Technique; D006801:Humans; D007700:Kinetics; D037102:Lectins / Q000276:immunology / Q000378:metabolism; D008247:Lysosomes / Q000737:chemistry* / Q000502:physiology*; D008264:Macrophages / Q000737:chemistry / Q000276:immunology* / Q000382:microbiology; D019909:Mycobacterium kansasii / Q000472:pathogenicity; D010588:Phagosomes / Q000502:physiology; D010980:Platelet Membrane Glycoproteins / Q000032:analysis* / Q000276:immunology; D011505:Protein-Tyrosine Kinases / Q000032:analysis* / Q000235:genetics / Q000276:immunology; D011518:Proto-Oncogene Proteins / Q000032:analysis* / Q000235:genetics / Q000276:immunology; D051572:Proto-Oncogene Proteins c-hck; D011956:Receptors, Cell Surface / Q000276:immunology / Q000378:metabolism; D017452:Receptors, IgG / Q000502:physiology; D011993:Recombinant Fusion Proteins / Q000032:analysis; D013395:Sucrose / Q000378:metabolism; D060149:Tetraspanin 30
chemical_list: D015703:Antigens, CD; C554586:CD63 protein, human; D037102:Lectins; D010980:Platelet Membrane Glycoproteins; D011518:Proto-Oncogene Proteins; D011956:Receptors, Cell Surface; D017452:Receptors, IgG; D011993:Recombinant Fusion Proteins; D060149:Tetraspanin 30; D013395:Sucrose; D011505:Protein-Tyrosine Kinases; C496631:HCK protein, human; D051572:Proto-Oncogene Proteins c-hck