Effect of D609 on phosphatidylcholine metabolism in the nuclei of LA-N-1 neuroblastoma cells: a key role for diacylglycerol

In our previous studies, TPA treatment of LA-N-1 cells stimulated the produ ction of diacylglycerol in nuclei, probably through the activation of a pho spholipase C. Stimulation of the synthesis of nuclear phosphatidylcholine b y the activation of CTP:phosphocholine cytidylyltransferase was also observ ed. The present data show that both effects were inhibited by the pretreatm ent of the cells with D609, a selective phosphatidylcholine-phospholipase C inhibitor, indicating that the diacylglycerol produced through the hydroly sis of phosphatidylcholine in the nuclei is reutilized for the synthesis of nuclear phosphatidylcholine and is required for the activation of CTP:phos phocholine cytidylyltransferase. (C) 2001 Published by Elsevier Science B.V . on behalf of the Federation of European Biochemical Societies.