title: Requirement for vacuolar H+ -ATPase activity and Ca2+ gradient during entry of rotavirus into MA104 cells.
abstract: 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.
authors.affiliation: Laboratorio de Fisiología Gastrointestinal, Instituto Venezolano de Investigaciones Científicas (IVIC), 1020A Caracas, Venezuela.
authors.forename: Maria Elena
authors.initials: ME
authors.lastname: Chemello
authors.forename: Olga Carolina
authors.initials: OC
authors.lastname: Aristimuño
authors.forename: Fabián
authors.initials: F
authors.lastname: Michelangeli
authors.forename: Marie-Christine
authors.initials: MC
authors.lastname: Ruiz
mesh_terms: 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
chemical_list: 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