Vacuoles induced by Helicobacter pylori toxin contain both late endosomal and lysosomal markers.
Intoxication of mammalian cells with the vacuolating toxin (VacA) released by Helicobacter pylori causes the formation of large acidic vacuoles containing the vacuolar ATPase proton pump and Rab7, a late endosome marker. Here, we describe a novel subcellular fractionation procedure, and we show that nanomolar concentrations of VacA induce a clear redistribution of lysosomal membrane glycoproteins among endocytic compartments. This redistribution is an early event in the process of cellular intoxication by VacA and precedes the formation of macroscopic vacuoles. The absence of the cation independent mannose 6-P receptor and the presence of Rab7 and of lysosomal membrane proteins in the newly formed compartment suggest that the vacuolating toxin induces the accumulation of a post-endosomal hybrid compartment presenting both late endosomal and lysosomal features.
Molinari
M
M
Centro CNR Biomembrane and Dipartimento di Scienze Biomediche, Università di Padova, 35100 Padova, Italy. toxin@civ.bio.unipd.it
Galli
C
C
Norais
N
N
Telford
J L
JL
Rappuoli
R
R
Luzio
J P
JP
Montecucco
C
C
D000818:Animals; D001426:Bacterial Proteins / Q000633:toxicity*; D015415:Biomarkers; D002458:Cell Fractionation; D002460:Cell Line; D002499:Centrifugation, Density Gradient; D006224:Cricetinae; D003603:Cytotoxins / Q000633:toxicity; D011992:Endosomes / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure; D019204:GTP-Binding Proteins / Q000032:analysis; D016480:Helicobacter pylori; D007668:Kidney; D008247:Lysosomes / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure; D008562:Membrane Glycoproteins / Q000187:drug effects / Q000378:metabolism; D006180:Proton-Translocating ATPases / Q000032:analysis; D017527:Receptor, IGF Type 2 / Q000032:analysis; D025262:Vacuolar Proton-Translocating ATPases; D014617:Vacuoles / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure; D020691:rab GTP-Binding Proteins; D000090802:rab7 GTP-Binding Proteins
D001426:Bacterial Proteins; D015415:Biomarkers; D003603:Cytotoxins; D008562:Membrane Glycoproteins; D017527:Receptor, IGF Type 2; C074689:VacA protein, Helicobacter pylori; D000090802:rab7 GTP-Binding Proteins; D019204:GTP-Binding Proteins; D025262:Vacuolar Proton-Translocating ATPases; D006180:Proton-Translocating ATPases; D020691:rab GTP-Binding Proteins