title: Inorganic phosphate uptake in intact vacuoles isolated from suspension-cultured cells of Catharanthus roseus (L.) G. Don under varying Pi status.
abstract: Inorganic phosphate (Pi) uptake across the vacuolar membrane of intact vacuoles isolated from Catharanthus roseus suspension-cultured cells was measured. Under low Pi status, Pi uptake into the vacuole was strongly activated compared to high Pi status. Since Pi uptake across the vacuolar membrane is correlated with H+ pumping, we examined the dependency of H+ pumping on plant Pi status. Both H+ pumping and the activities of the vacuolar H+-pumps, the V-type H+-ATPase and the H+-PPase were enhanced under low Pi status. Despite this increase in H+ pumping, Western blot analysis showed no distinct increase in the amount of proton pump proteins. Possible mechanisms for the activation of Pi uptake into the vacuole under low Pi status are discussed.
authors.affiliation: Department of Biology, Faculty of Science, Kobe University, Rokkodai 1-1, Nada, Kobe 678-8501, Japan.
authors.forename: Miwa
authors.initials: M
authors.lastname: Ohnishi
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Mimura
authors.forename: Tomoko
authors.initials: T
authors.lastname: Tsujimura
authors.forename: Naoto
authors.initials: N
authors.lastname: Mitsuhashi
authors.forename: Setsuko
authors.initials: S
authors.lastname: Washitani-Nemoto
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Maeshima
authors.forename: Enrico
authors.initials: E
authors.lastname: Martinoia
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D015153:Blotting, Western; D030008:Catharanthus / Q000166:cytology / Q000378:metabolism*; D002478:Cells, Cultured; D004591:Electrophoresis, Polyacrylamide Gel; D010710:Phosphates / Q000378:metabolism*; D017494:Proton Pumps / Q000378:metabolism; D006180:Proton-Translocating ATPases / Q000378:metabolism; D013997:Time Factors; D014617:Vacuoles / Q000378:metabolism*
chemical_list: D010710:Phosphates; D017494:Proton Pumps; D000255:Adenosine Triphosphate; D006180:Proton-Translocating ATPases