Involvement of 14-3-3 proteins in the osmotic regulation of H+-ATPase in plant plasma membranes.
Taking the binding of fusicoccin to plasma membranes as an indicator of complex formation between the 14-3-3 dimer and H+-ATPase, we assessed the effect of osmotic stress on the interaction of these proteins in suspension-cultured cells of sugar beet (Beta vulgaris L.). An increase in osmolarity of the cell incubation medium, accompanied by a decrease in turgor, was found to activate the H+ efflux 5-fold. The same increment was observed in the number of high-affinity fusicoccin-binding sites in isolated plasma membranes: the 14-3-3 content in the membranes increased 2- to 3-fold, while the H+-ATPase activity changed only slightly. The data obtained indicate that osmotic regulation of H+-ATPase in the plant plasma membrane is achieved via modulation of the coupling between H+ transport and ATP hydrolysis, and that such regulation involves 14-3-3 proteins.
Babakov
A V
AV
Institute of Agricultural Biotechnology RAAS, Moscow, Russia. avb@iab.ac.ru
Chelysheva
V V
VV
Klychnikov
O I
OI
Zorinyanz
S E
SE
Trofimova
M S
MS
De Boer
A H
AH
D048948:14-3-3 Proteins; D002478:Cells, Cultured; D019281:Dimerization; D006706:Homeostasis; D006863:Hydrogen-Ion Concentration; D006982:Hypertonic Solutions; D009994:Osmolar Concentration; D010945:Plants, Edible / Q000166:cytology / Q000201:enzymology / Q000502:physiology*; D006180:Proton-Translocating ATPases / Q000378:metabolism*; D013012:Sorbitol / Q000494:pharmacology; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism*
D048948:14-3-3 Proteins; D006982:Hypertonic Solutions; D013012:Sorbitol; D014446:Tyrosine 3-Monooxygenase; D006180:Proton-Translocating ATPases