Dual regulation of phospholipase D1 by protein kinase C alpha in vivo.
The regulation of phospholipase D1 (PLD1), which has been shown to be activated by protein kinase C (PKC) alpha, was investigated in the human melanoma cell lines. In G361 cell line, which lacks PKCalpha, 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced PLD activation was potentiated by introducing PKCalpha by the adenovirus vector. The kinase-negative PKCalpha elevated TPA-induced PLD activity less significantly than the wild type. A PKC specific inhibitor GF109203X lowered PLD activation in the cells expressing PKCalpha, but did not prevent PLD potentiation induced by the kinase-negative PKCalpha. Expression of PKCbetaII and the kinase-negative PKCbetaII enhanced TPA-stimulated PLD activity moderately in MeWo cell line, in which PKCbetaII is absent. Furthermore, the TPA treatment increased the association of PKCalpha, PKCbetaII, and their kinase-negative mutants with PLD1 in melanoma cells. These results indicate that PLD1 is dually regulated through phosphorylation as well as through the protein-protein interaction by PKCalpha, and probably by PKCbetaII, in vivo.
Oka
Masahiro
M
Department of Dermatology, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan.
Hitomi
Tomohiro
T
Okada
Taro
T
Nakamura Si
Shun-ichi
S
Nagai
Hiroshi
H
Ohba
Motoi
M
Kuroki
Toshio
T
Kikkawa
Ushio
U
Ichihashi
Masamitsu
M
D000818:Animals; D002460:Cell Line; D002478:Cells, Cultured; D004789:Enzyme Activation; D006801:Humans; D007527:Isoenzymes / Q000378:metabolism*; D008544:Melanocytes / Q000187:drug effects / Q000201:enzymology; D008545:Melanoma / Q000201:enzymology*; D010739:Phospholipase D / Q000378:metabolism*; D010766:Phosphorylation; D020033:Protein Isoforms / Q000378:metabolism; D011493:Protein Kinase C / Q000378:metabolism*; D051571:Protein Kinase C-alpha; D051381:Rats; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014407:Tumor Cells, Cultured
D007527:Isoenzymes; D020033:Protein Isoforms; C496628:PRKCA protein, human; D011493:Protein Kinase C; D051571:Protein Kinase C-alpha; D010739:Phospholipase D; C106801:phospholipase D1; D013755:Tetradecanoylphorbol Acetate