title: The vacuolar ATPase proton pump is present on intracellular vacuoles induced by Helicobacter pylori.
abstract: Cytotoxic strains of Helicobacter pylori cause an intense vacuolar degeneration of cells, due to the enlargement of late endosomes in the presence of membrane permeant weak bases. Bafilomycins, specific inhibitors of the vacuolar-type (V-) ATPase proton pump, prevent vacuole formation. The presence of the V-ATPase on vacuolar membranes was demonstrated by immunofluorescence with a monoclonal antibody (MAb) specific for the human 116-kDa regulatory subunit. The V-ATPase co-localised with the late endosomal marker rab7 on vacuolar membranes. In contrast, the early recycling endosomal compartment was not altered by the VacA cytotoxin, although it was endowed with the V-ATPase. Endocytosis of a MAb against the 116-kDa regulatory subunit of V-ATPase blocked endosomal acidification in HeLa cells and prevented VacA action. These results indicate that selective swelling of late endosomes, due to accumulation of osmotically active weak bases driven by the V-ATPase, is essential for vacuole formation.
authors.affiliation: Dipartimento di Scienze Biomediche, University of Padova, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Papini
authors.forename: E
authors.initials: E
authors.lastname: Gottardi
authors.forename: B
authors.initials: B
authors.lastname: Satin
authors.forename: M
authors.initials: M
authors.lastname: de Bernard
authors.forename: P
authors.initials: P
authors.lastname: Massari
authors.forename: J
authors.initials: J
authors.lastname: Telford
authors.forename: R
authors.initials: R
authors.lastname: Rappuoli
authors.forename: S B
authors.initials: SB
authors.lastname: Sato
authors.forename: C
authors.initials: C
authors.lastname: Montecucco
mesh_terms: D000251:Adenosine Triphosphatases / Q000032:analysis* / Q000276:immunology; D000818:Animals; D000911:Antibodies, Monoclonal; D001426:Bacterial Proteins / Q000494:pharmacology; D003603:Cytotoxins / Q000494:pharmacology; D019084:Fluorescent Antibody Technique, Indirect; D006168:Guinea Pigs; D006367:HeLa Cells; D016480:Helicobacter pylori / Q000472:pathogenicity / Q000502:physiology*; D006801:Humans; D007106:Immune Sera; D007425:Intracellular Membranes / Q000201:enzymology; D051379:Mice; D017494:Proton Pumps / Q000502:physiology*; D011817:Rabbits; D014617:Vacuoles / Q000187:drug effects / Q000201:enzymology* / Q000648:ultrastructure
chemical_list: D000911:Antibodies, Monoclonal; D001426:Bacterial Proteins; D003603:Cytotoxins; D007106:Immune Sera; D017494:Proton Pumps; C074689:VacA protein, Helicobacter pylori; D000251:Adenosine Triphosphatases