Inorganic phosphate uptake in intact vacuoles isolated from suspension-cultured cells of Catharanthus roseus (L.) G. Don under varying Pi status.
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.
Ohnishi
Miwa
M
Department of Biology, Faculty of Science, Kobe University, Rokkodai 1-1, Nada, Kobe 678-8501, Japan.
Mimura
Tetsuro
T
Tsujimura
Tomoko
T
Mitsuhashi
Naoto
N
Washitani-Nemoto
Setsuko
S
Maeshima
Masayoshi
M
Martinoia
Enrico
E
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*
D010710:Phosphates; D017494:Proton Pumps; D000255:Adenosine Triphosphate; D006180:Proton-Translocating ATPases