title: Helicobacter pylori toxin VacA induces vacuole formation by acting in the cell cytosol.
abstract: Cells exposed to Helicobacter pylori toxin VacA develop large vacuoles that originate from massive swelling of membranous compartments of late stages of the endocytic pathway. To determine if the toxin is active from the cell cytosol, cells were either microinjected with toxin or transfected with plasmids encoding VacA. Both procedures cause formation of intracellular vacuoles. Cytosolic localization of the toxin was assessed by indirect immunofluorescence with specific antibodies and by expression of an active green fluorescence protein (GFP)-VacA chimera. Vacuoles induced by internally produced VacA are morphologically and functionally identical to those induced by externally added toxin. It is concluded that VacA is a toxin acting intracellularly by altering a cytosol-exposed target, possibly involved in the control of membrane trafficking.
authors.affiliation: Centro CNR Biomembrane and Dipartimento di Scienze Biomediche Sperimentali dell'Università di Padova, Italy.
authors.forename: M
authors.initials: M
authors.lastname: de Bernard
authors.forename: B
authors.initials: B
authors.lastname: Arico
authors.forename: E
authors.initials: E
authors.lastname: Papini
authors.forename: R
authors.initials: R
authors.lastname: Rizzuto
authors.forename: G
authors.initials: G
authors.lastname: Grandi
authors.forename: R
authors.initials: R
authors.lastname: Rappuoli
authors.forename: C
authors.initials: C
authors.lastname: Montecucco
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002678:Chimera; D003587:Cytomegalovirus / Q000235:genetics; D003600:Cytosol; D003603:Cytotoxins / Q000235:genetics / Q000378:metabolism*; D012321:DNA-Directed RNA Polymerases / Q000235:genetics; D015870:Gene Expression; D049452:Green Fluorescent Proteins; D006367:HeLa Cells; D016480:Helicobacter pylori / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007202:Indicators and Reagents; D007700:Kinetics; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D008845:Microinjections; D011401:Promoter Regions, Genetic; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D014162:Transfection; D014617:Vacuoles; D014764:Viral Proteins
chemical_list: D001426:Bacterial Proteins; D003603:Cytotoxins; D007202:Indicators and Reagents; D008164:Luminescent Proteins; D011993:Recombinant Fusion Proteins; C074689:VacA protein, Helicobacter pylori; D014764:Viral Proteins; D049452:Green Fluorescent Proteins; C062210:bacteriophage T7 RNA polymerase; D012321:DNA-Directed RNA Polymerases