Requirement for vacuolar H+ -ATPase activity and Ca2+ gradient during entry of rotavirus into MA104 cells.
The mechanism by which rotavirus and other nonenveloped viruses enter the cell is still not clear. We have proposed an endocytosis model where the critical step for virus uncoating and membrane permeabilization is the decrease in Ca(2+) concentration in the endosome. In this paper, we monitored rotavirus entry by measuring alpha-sarcin-rotavirus coentry and infectivity in MA104 cells. The participation of endocytosis, acidification, and endosomal Ca(2+) concentration on virus entry was studied by inhibiting the endosomal H(+)-ATPase with bafilomycin A1 and/or increasing the extracellular calcium reservoir by addition of 10 mM CaEGTA. Rotavirus-alpha-sarcin coentry was inhibited by bafilomycin A1 and by addition of 10 mM CaEGTA. These effects were additive. These substances induced a significant inhibition of infectivity without affecting virus binding and postentry steps. These results are compatible with the interpretation that bafilomycin A1 and CaEGTA block rotavirus penetration from the endosome into the cytoplasm and support our hypothesis of a Ca(2+)-dependent endocytosis model.
Chemello
Maria Elena
ME
Laboratorio de Fisiología Gastrointestinal, Instituto Venezolano de Investigaciones Científicas (IVIC), 1020A Caracas, Venezuela.
Aristimuño
Olga Carolina
OC
Michelangeli
Fabián
F
Ruiz
Marie-Christine
MC
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002118:Calcium / Q000502:physiology*; D002478:Cells, Cultured; D004533:Egtazic Acid / Q000494:pharmacology; D004705:Endocytosis; D004722:Endoribonucleases / Q000493:pharmacokinetics; D005656:Fungal Proteins; D006863:Hydrogen-Ion Concentration; D018942:Macrolides; D008715:Methionine / Q000378:metabolism; D012401:Rotavirus / Q000502:physiology*; D013552:Swine; D025262:Vacuolar Proton-Translocating ATPases / Q000502:physiology*; D014779:Virus Replication
D000900:Anti-Bacterial Agents; D005656:Fungal Proteins; D018942:Macrolides; C057620:bafilomycin A; C014801:alpha-sarcin; D004533:Egtazic Acid; D008715:Methionine; D004722:Endoribonucleases; D025262:Vacuolar Proton-Translocating ATPases; D002118:Calcium