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  • The EMBO Journal (1999) 18, 5517 - 5527
  • doi:10.1093/emboj/18.20.5517

Formation of anion-selective channels in the cell plasma membrane by the toxin VacA of Helicobacter pylori is required for its biological activity

Ildikò Szabò1,2,6, Sandra Brutsche1,3,6, Francesco Tombola1, Monica Moschioni1, Barbara Satin1, John L. Telford4, Rino Rappuoli4, Cesare Montecucco1, Emanuele Papini5,7 and Mario Zoratti1,7

  1. Centro CNR Biomembrane e Dipartimento di Scienze Biomediche, Università di Padova, Via G. Colombo 3, 35121 Padova, Italy
  2. Present address: Department of Biology, University of Padova, Via G. Colombo 3, 35121 Padova, Italy
  3. Present address: Hoechst Roussel Vet GmbH, Building H813, 117A, Research Pharmaceutical, D-65926 Frankfurt am Main, Germany
  4. Centro Ricerche IRIS, CHIRON-Vaccines, Via Fiorentina 1, 53100 Siena, Italy
  5. Dipartimento di Scienze Biomediche e Oncologia Umana, Universita' di Bari, Piazza Giulio Cesare 11, 70100 Bari, Italy
  6. I.Szabò and S.Brutsche contributed equally to this study
  7. E.Papini and M.Zoratti share last authorship

Correspondence to:

Emanuele Papini, E-mail: papinie@civ.bio.unipd.it

Mario Zoratti, E-mail: zoratti@civ.bio.unipd.it

Received 7 June 1999; Accepted 31 August 1999; Revised 31 August 1999

The vacuolating toxin VacA, a major determinant of Helicobacter pylori-associated gastric diseases, forms anion-selective channels in artificial planar lipid bilayers. Here we show that VacA increases the anion permeability of the HeLa cell plasma membrane and determines membrane depolarization. Electrophysiological and pharmacological approaches indicated that this effect is due to the formation of low-conductance VacA pores in the cell plasma membrane and not to the opening of Ca2+- or volume-activated chloride channels. VacA-dependent increase of current conduction both in artificial planar lipid bilayers and in the cellular system was effectively inhibited by the chloride channel blocker 5-nitro-2-(3-phenylpropylamino) benzoic acid (NPPB), while2-[(2-cyclopentenyl-6,7dichloro-2,3-dihydro-2-methyl-1-oxo-1H-inden-5-yl)oxy]acetic acid (IAA-94) was less effective. NPPB inhibited and partially reversed the vacuolation of HeLa cells and the increase of ion conductivity of polarized Madine Darby canine kidney cell monolayers induced by VacA, while IAA-94 had a weaker effect. We conclude that pore formation by VacA accounts for plasma membrane permeabilization and is required for both cell vacuolation and increase of trans-epithelial conductivity.

  • Keywords:

    • anion channel,
    • epithelial permeability,
    • Helicobacter pylori,
    • VacA,
    • vacuolation