Identification of the Helicobacter pylori VacA toxin domain active in the cell cytosol.
Cells exposed to Helicobacter pylori toxin VacA develop large vacuoles which originate from massive swelling of membranous compartments at late stages of the endocytic pathway. When expressed in the cytosol, VacA induces vacuolization as it does when added from outside. This and other evidence indicate that VacA is a toxin capable of entering the cell cytosol, where it displays its activity. In this study, we have used cytosolic expression to identify the portion of the toxin molecule responsible for the vacuolating activity. VacA mutants with deletions at the C and N termini were generated, and their activity was analyzed upon expression in HeLa cells. We found that the vacuolating activity of VacA resides in the amino-terminal region, the whole of which is required for its intracellular activity.
de Bernard
M
M
Centro CNR Biomembrane and Dipartimento di Scienze Biomediche, Università di Padova, 35121 Padova, Italy.
Burroni
D
D
Papini
E
E
Rappuoli
R
R
Telford
J
J
Montecucco
C
C
D001426:Bacterial Proteins / Q000235:genetics / Q000633:toxicity*; D001427:Bacterial Toxins / Q000235:genetics / Q000633:toxicity*; D003600:Cytosol; D006367:HeLa Cells / Q000187:drug effects / Q000473:pathology; D016480:Helicobacter pylori / Q000472:pathogenicity*; D006801:Humans; D010446:Peptide Fragments / Q000235:genetics / Q000633:toxicity; D011994:Recombinant Proteins / Q000633:toxicity; D017384:Sequence Deletion; D014617:Vacuoles
D001426:Bacterial Proteins; D001427:Bacterial Toxins; D010446:Peptide Fragments; D011994:Recombinant Proteins; C074689:VacA protein, Helicobacter pylori