Prostaglandin F2 alpha activates phospholipase D independently from activation of protein kinase C in osteoblast-like cells.
We previously reported that prostaglandin F2 alpha (PGF2 alpha) receptor is coupled to pertussis toxin (PTX)-sensitive GTP-binding protein (G protein) in osteoblast-like MC3T3-E1 cells [Miwa et al. (1990): Biochem Biophys Res Commun 171:1229-1235]. In the present study, we examined the effect of PGF2 alpha on the activation of phosphatidylcholine-hydrolyzing phospholipase D in MC3T3-E1 cells. PGF2 alpha stimulated the formation of choline in a dose-dependent manner in the range between 10 nM and 10 microM. The formation of choline was stimulated by 12-O-tetradecanoylphorbol-13-acetate (TPA), a protein kinase C (PKC)-activating phorbol ester. 4 alpha-Phorbol 12, 13-didecanoate, a PKC-nonactivating phorbol ester, had little effect on choline formation. The formation of choline stimulated by a combination of PGF2 alpha and TPA was additive. Staurosporine, an inhibitor for protein kinases, which inhibited the effect of TPA on choline formation, dose-dependently enhanced the formation of choline induced by PGF2 alpha. NaF, an activator of G protein, stimulated the formation of choline. The formation of choline stimulated by a combination of PGF2 alpha and NaF was not additive. NaF-induced formation of choline was dose-dependently enhanced by staurosporine. PTX dose-dependently inhibited the PGF2 alpha-induced formation of choline. These results strongly suggest that PGF 2 alpha activates phospholipase D independently from the activation of PKC in osteoblast-like cells and PTX-sensitive G protein is involved in the PGF2 alpha-induced phospholipase D activation.
Department of Biochemistry, Institute for Developmental Research, Aichi Prefectural Colony, Japan.
O
O
Kozawa
A
A
Suzuki
J
J
Kotoyori
H
H
Tokuda
Y
Y
Watanabe
Y
Y
Ito
Y
Y
Oiso
D000470:Alkaloids / Q000494:pharmacology; D002460:Cell Line; D002794:Choline / Q000096:biosynthesis; D015237:Dinoprost / Q000494:pharmacology*; D004789:Enzyme Activation / Q000187:drug effects; D019204:GTP-Binding Proteins / Q000187:drug effects; D006868:Hydrolysis; D010006:Osteoblasts / Q000187:drug effects* / Q000201:enzymology; D037342:Pertussis Toxin; D010713:Phosphatidylcholines / Q000378:metabolism; D010739:Phospholipase D / Q000187:drug effects* / Q000378:metabolism; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000187:drug effects* / Q000378:metabolism; D012969:Sodium Fluoride / Q000494:pharmacology; D019311:Staurosporine; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D000470:Alkaloids; D010713:Phosphatidylcholines; D010566:Virulence Factors, Bordetella; D012969:Sodium Fluoride; D015237:Dinoprost; D037342:Pertussis Toxin; D011493:Protein Kinase C; D010739:Phospholipase D; D019204:GTP-Binding Proteins; D019311:Staurosporine; D002794:Choline; D013755:Tetradecanoylphorbol Acetate