title: Lack of acidification in Mycobacterium phagosomes produced by exclusion of the vesicular proton-ATPase.
abstract: The success of Mycobacterium species as pathogens depends on their ability to maintain an infection inside the phagocytic vacuole of the macrophage. Although the bacteria are reported to modulate maturation of their intracellular vacuoles, the nature of such modifications is unknown. In this study, vacuoles formed around Mycobacterium avium failed to acidify below pH 6.3 to 6.5. Immunoelectron microscopy of infected macrophages and immunoblotting of isolated phagosomes showed that Mycobacterium vacuoles acquire the lysosomal membrane protein LAMP-1, but not the vesicular proton-adenosine triphosphatase (ATPase) responsible for phagosomal acidification. This suggests either a selective inhibition of fusion with proton-ATPase-containing vesicles or a rapid removal of the complex from Mycobacterium phagosomes.
authors.affiliation: Department of Molecular Microbiology, Washington University Medical Center, St. Louis, MO 63110.
authors.forename: S
authors.initials: S
authors.lastname: Sturgill-Koszycki
authors.forename: P H
authors.initials: PH
authors.lastname: Schlesinger
authors.forename: P
authors.initials: P
authors.lastname: Chakraborty
authors.forename: P L
authors.initials: PL
authors.lastname: Haddix
authors.forename: H L
authors.initials: HL
authors.lastname: Collins
authors.forename: A K
authors.initials: AK
authors.lastname: Fok
authors.forename: R D
authors.initials: RD
authors.lastname: Allen
authors.forename: S L
authors.initials: SL
authors.lastname: Gluck
authors.forename: J
authors.initials: J
authors.lastname: Heuser
authors.forename: D G
authors.initials: DG
authors.lastname: Russell
mesh_terms: D000818:Animals; D015703:Antigens, CD; D006863:Hydrogen-Ion Concentration; D007894:Leishmania mexicana / Q000502:physiology; D051907:Lysosomal Membrane Proteins; D008264:Macrophages / Q000378:metabolism / Q000382:microbiology* / Q000469:parasitology / Q000648:ultrastructure; D008561:Membrane Fusion; D008562:Membrane Glycoproteins / Q000378:metabolism; D051379:Mice; D016253:Microscopy, Immunoelectron; D009162:Mycobacterium avium / Q000502:physiology*; D009169:Mycobacterium tuberculosis / Q000502:physiology; D010588:Phagosomes / Q000378:metabolism / Q000382:microbiology* / Q000469:parasitology / Q000648:ultrastructure; D006180:Proton-Translocating ATPases / Q000378:metabolism*; D014617:Vacuoles / Q000378:metabolism / Q000382:microbiology / Q000469:parasitology / Q000648:ultrastructure
chemical_list: D015703:Antigens, CD; D051907:Lysosomal Membrane Proteins; D008562:Membrane Glycoproteins; D006180:Proton-Translocating ATPases