Nuclear diacylglycerol kinase-θ is activated in response to nerve growth factor stimulation of PC12 cells

• Published in: Cellular signalling Vol. 16; no. 11; pp. 1263 - 1271
• Main Authors: Tabellini, Giovanna, Billi, Anna Maria, Falà, Federica, Cappellini, Alessandra, Evagelisti, Camilla, Manzoli, Lucia, Cocco, Lucio, Martelli, Alberto Maria
• Format: Journal Article
• Language: English
• Published: England Elsevier Inc 01.11.2004
• Subjects: Animals; Antibodies, Monoclonal - pharmacology; Cell Nucleus - drug effects; Cell Nucleus - metabolism; Culture Media, Serum-Free - pharmacology; Cytoplasm - drug effects; Cytoplasm - metabolism; Diacylglycerol Kinase - antagonists & inhibitors; Diacylglycerol Kinase - metabolism; Diacylglycerol kinase-θ; Down-Regulation - drug effects; Down-Regulation - physiology; Inositol lipid cycle; Isoenzymes - antagonists & inhibitors; Isoenzymes - metabolism; Nerve Growth Factor - metabolism; Nerve Growth Factor - pharmacology; Nuclear matrix; Nuclear Matrix - drug effects; Nuclear Matrix - metabolism; Nucleus; PC12 Cells; Phosphatidic acid; Phosphatidic Acids - metabolism; Phosphatidylserine; Phosphatidylserines - metabolism; Phosphatidylserines - pharmacology; Rats; Signal Transduction - drug effects; Signal Transduction - physiology; Up-Regulation - drug effects; Up-Regulation - physiology; Nucleus; DG; PS; PLD; TLC; PI(3,4,5)P 3; BSA; OG; PI(4,5)P 2; CLSM; Phosphatidylserine; Phosphatidic acid; PIP 5-kinase; EGF; DGK; PKC; IGF-1; Inositol lipid cycle; NGF; ECL; PA; SDS-PAGE; PC; Diacylglycerol kinase-θ; PMSF; NGS; Nuclear matrix; D-MEM
• ISSN: 0898-6568; 1873-3913
• DOI: 10.1016/j.cellsig.2004.03.018

Previous evidence from independent laboratories has shown that the nucleus contains diacylglycerol kinase (DGK) isoforms, i.e., the enzymes, which yield phosphatidic acid from diacylglycerol, thus terminating protein kinase C-mediated signaling events. A DGK isoform, which resides in the nucleus of PC12 cells, is DGK-θ. Here, we show that nerve growth factor (NGF) treatment of serum-starved PC12 cells results in the stimulation of both a cytoplasmic and a nuclear DGK activity. However, time course analysis shows that cytoplasmic DGK activity peaked earlier than its nuclear counterpart. While nuclear DGK activity was dramatically down-regulated by a monoclonal antibody known for selectively inhibiting DGK-θ, cytoplasmic DGK activity was not. Moreover, nuclear DGK activity was stimulated by phosphatidylserine, an anionic phospholipid that had no effect on cytoplasmic DGK activity. Upon NGF stimulation, the amount and the activity of DGK-θ, which was bound to the insoluble nuclear matrix fraction, substantially increased. Epidermal growth factor up-regulated a nuclear DGK activity insensitive to anti-DGK-θ monoclonal antibody. Overall, our findings identify nuclear DGK-θ as a down-stream target of NGF signaling in PC12 cells.