Vacuolation induced by VacA toxin of Helicobacter pylori requires the intracellular accumulation of membrane permeant bases, Cl(-) and water.
The protein vacuolating toxin A (VacA) of Helicobacter pylori converts late endosomes into large vacuoles in the presence of permeant bases. Here it is shown that this phenomenon corresponds to an accumulation of permeant bases and Cl(-) in HeLa cells and requires the presence of extracellular Cl(-). The net influx of Cl(-) is due to electroneutral, Na(+), K(+), 2Cl(-) cotransporter-mediated transport. Cell vacuolation leads to cell volume increase, consistent with water flux into the cell, while hyper-osmotic media decreased vacuole formation. These data represent the first evidence that VacA-treated cells undergo an osmotic unbalance, reinforcing the hypothesis that the VacA chloride channel is responsible for cell vacuolation.
Morbiato
L
L
Centro CNR Biomembrane, Department of Biomedical Sciences, University of Padova, Padua, Italy.
Tombola
F
F
Campello
S
S
Del Giudice
G
G
Rappuoli
R
R
Zoratti
M
M
Papini
E
E
D000643:Ammonium Chloride / Q000494:pharmacology; D001426:Bacterial Proteins / Q000378:metabolism / Q000633:toxicity*; D002034:Bumetanide / Q000494:pharmacology; D002463:Cell Membrane Permeability; D048429:Cell Size; D002712:Chlorides / Q000378:metabolism*; D011992:Endosomes / Q000378:metabolism; D006367:HeLa Cells; D016480:Helicobacter pylori; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008744:Methylamines / Q000378:metabolism; D009997:Osmotic Pressure; D049994:Sodium Potassium Chloride Symporter Inhibitors; D028021:Sodium-Potassium-Chloride Symporters / Q000378:metabolism; D014617:Vacuoles / Q000187:drug effects / Q000378:metabolism*; D014867:Water / Q000378:metabolism*
D001426:Bacterial Proteins; D002712:Chlorides; D008744:Methylamines; D049994:Sodium Potassium Chloride Symporter Inhibitors; D028021:Sodium-Potassium-Chloride Symporters; C074689:VacA protein, Helicobacter pylori; D000643:Ammonium Chloride; D014867:Water; D002034:Bumetanide; C027451:methylamine