Nuclear diacylglycerol kinase-theta is activated in response to nerve growth factor stimulation of PC12 cells.
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-theta. 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-theta, 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-theta, which was bound to the insoluble nuclear matrix fraction, substantially increased. Epidermal growth factor up-regulated a nuclear DGK activity insensitive to anti-DGK-theta monoclonal antibody. Overall, our findings identify nuclear DGK-theta as a down-stream target of NGF signaling in PC12 cells.
Tabellini
Giovanna
G
Dipartimento di Scienze Anatomiche Umane e Fisiopatologia dell'Apparato Locomotore, Cell Signalling Laboratory, Università degli Studi di Bologna, via Irnerio 48, 40126, Italy.
Billi
Anna Maria
AM
Falà
Federica
F
Cappellini
Alessandra
A
Evagelisti
Camilla
C
Manzoli
Lucia
L
Cocco
Lucio
L
Martelli
Alberto Maria
AM
D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism*; D016895:Culture Media, Serum-Free / Q000494:pharmacology; D003593:Cytoplasm / Q000187:drug effects / Q000378:metabolism; D019852:Diacylglycerol Kinase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D015536:Down-Regulation / Q000187:drug effects / Q000502:physiology; D007527:Isoenzymes / Q000037:antagonists & inhibitors / Q000378:metabolism; D020932:Nerve Growth Factor / Q000378:metabolism* / Q000494:pharmacology; D015530:Nuclear Matrix / Q000187:drug effects / Q000378:metabolism; D016716:PC12 Cells; D010712:Phosphatidic Acids / Q000378:metabolism; D010718:Phosphatidylserines / Q000378:metabolism / Q000494:pharmacology; D051381:Rats; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D015854:Up-Regulation / Q000187:drug effects / Q000502:physiology
D000911:Antibodies, Monoclonal; D016895:Culture Media, Serum-Free; D007527:Isoenzymes; D010712:Phosphatidic Acids; D010718:Phosphatidylserines; D020932:Nerve Growth Factor; D019852:Diacylglycerol Kinase