Lipid phosphorylation takes place within the chloroplast envelope. In addit
ion to phosphatidic acid, phosphatidylinositol phosphate, and their corresp
onding lyse-derivatives, we found that two novel lipids underwent phosphory
lation in envelopes, particularly in the presence of carrier-free [gamma-P-
32]ATP, These two lipids incorporated radioactive phosphate in chloroplasts
in the presence of [gamma-P-32]ATP or [P-32]P-i and light. Interestingly,
these two lipids were preferentially phosphorylated in envelope membranes i
n the presence [gamma-P-32]CTP, as the phosphoryl donor, or [gamma-P-32]ATP
, when supplemented with CDP and nucleoside diphosphate kinase II. The lipi
d kinase activity involved in this reaction was specifically inhibited in t
he presence of cytosine 5'-O-(thiotriphosphate) (CTP gamma S) and sensitive
to CTP chase, thereby showing that both lipids are phosphorylated by an en
velope CTP-dependent lipid kinase. The lipids were identified as phosphoryl
ated galactolipids by using an acid hydrolysis procedure that generated gal
actose B-phosphate, CTP gamma S did not affect the import of the small ribu
lose-bisphosphate carboxylase/oxygenase subunit into chloroplasts, the poss
ible physiological role of this novel CTP-dependent galactolipid kinase act
ivity in the chloroplast envelope is discussed.