Three distinct lipid kinase activities are present in spinach chloroplast envelope membranes: phosphatidylinositol phosphorylation is sensitive to wortmannin and not dependent on chloroplast ATP.
Chloroplast envelope membranes display properties that are important in lipid synthesis, regulation of metabolites, and protein transport, as well as in signal transduction. The recent discovery showing that phosphorylation of lipids occurs in envelope membranes provides a new approach for understanding the role of chloroplast lipids in these processes. The present investigation shows that three major lipid kinase activities are at least present in envelope membranes. These activities greatly depend on external conditions, such as pH, ATP concentrations, temperature, and chloroplast ATP and wortmannin sensitivity. Two types of phosphorylated lipid couples displayed similar intrinsic responses toward these biochemical parameters, namely phosphatidic acid (PA) and its lysoderivative (LPA) and monogalactosyl-phosphate-diacylglycerol (MGpDG) and its lysoderivative (LMGpDG), but not phosphatidylinositol-monophosphate (PIP) and its lysoderivative (LPIP). Phosphorylation of phosphatidylinositol was not dependent on chloroplast ATP, but was sensitive toward wortmannin in intact chloroplasts and outer envelope membrane vesicles.
Bovet
L
L
Laboratoire de Physiologie Végétale, Université de Neuchâtel, Rue Emile Argand 13, CH-2007 Neuchâtel, Switzerland. Lucien.Bovet@bota.unine.ch
Müller
M O
MO
Siegenthaler
P A
PA
D000255:Adenosine Triphosphate / Q000378:metabolism; D000730:Androstadienes / Q000494:pharmacology; D002736:Chloroplasts / Q000187:drug effects / Q000201:enzymology*; D019852:Diacylglycerol Kinase / Q000378:metabolism*; D007425:Intracellular Membranes / Q000201:enzymology; D008563:Membrane Lipids / Q000378:metabolism; D010716:Phosphatidylinositols / Q000378:metabolism; D010766:Phosphorylation; D010770:Phosphotransferases / Q000378:metabolism*; D018724:Spinacia oleracea / Q000201:enzymology; D000077191:Wortmannin
D000730:Androstadienes; D008563:Membrane Lipids; D010716:Phosphatidylinositols; D000255:Adenosine Triphosphate; D010770:Phosphotransferases; D019852:Diacylglycerol Kinase; D000077191:Wortmannin