Rapid light-induced changes in phosphoinositide kinases and H+-ATPase in plasma membrane of sunflower hypocotyls

• Published in: The Journal of biological chemistry 1990-09, Vol.265 (25), p.14817-14821
• Main Authors: Memon, A.R. (Middle East Technical University, Ankara, Turkey), Boss, W.F
• Format: Article
• Language: English
• Subjects: 1-Phosphatidylinositol 4-Kinase; ADENOSINETRIPHOSPHATASE; Analytical, structural and metabolic biochemistry; Biological and medical sciences; Cell Membrane - enzymology; CELL STRUCTURE; Darkness; Enzymes and enzyme inhibitors; ESTRUCTURA CELULAR; FOSFOLIPIDOS; Fundamental and applied biological sciences. Psychology; HELIANTHUS ANNUUS; HIDROLASAS; HYDROLASE; HYDROLASES; Inositol Phosphates - pharmacology; Kinetics; LIGHT; LIGHT IRRADIATION; LUMIERE; LUZ; Membrane Lipids - isolation & purification; Membrane Lipids - metabolism; PHOSPHATIDE; PHOSPHATIDYLINOSITOLS; Phosphatidylinositols - pharmacology; PHOSPHOLIPIDS; Phospholipids - isolation & purification; Phospholipids - metabolism; Phosphotransferases - metabolism; Phosphotransferases - radiation effects; Plants - enzymology; Proton-Translocating ATPases - metabolism; Proton-Translocating ATPases - radiation effects; STRUCTURE CELLULAIRE; TRANSFERASAS; TRANSFERASE; TRANSFERASES; Vanadates - pharmacology
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/S0021-9258(18)77187-1

Irradiation of sunflower (Helianthus annuus L. cv. Russian Mammoth) hypocotyls with white light resulted in a 51% decrease in plasma membrane phosphatidylinositol monophosphate (PIP) kinase activity. As little as 10 s of white light irradiation was sufficient to lower the phosphatidylinositol bisphosphate (PIP2) produced in the in vitro phosphorylation assay. This decrease was not caused by an increase in phospholipase C activity since analysis of the water-soluble products indicated no increase in inositol bisphosphate or inositol trisphosphate. Treatment of the plasma membrane with 200 microM vanadate prior to phosphorylation enhanced the PIP kinase and appeared to overcome the light inhibition. In addition to decreasing the PIP kinase activity, light irradiation resulted in a corresponding decrease in the H(+)-ATPase activity to 53% of the dark control values. The plasma membrane ATPase activity increased approximately 2-fold when PIP or PIP2 was added to the isolated membranes. Thus, effects of external stimuli on the level of plasma membrane PIP or PIP2 could affect plasma membrane ATPase activity directly and thereby provide an alternative mechanism for control of cell growth.