A protein kinase C isozyme, nPKC epsilon, is involved in the activation of NF-kappa B by 12-O-tetradecanoylphorbol-13-acetate (TPA) in rat 3Y1 fibroblasts.
In order to examine whether PKC is involved in the activation of NF-kappa B by TPA, we overexpressed a variety of PKC isozymes in rat 3Y1 fibroblasts and monitored the expression of the co-transfected reporter NF-kappa B gene. In contrast to TPA response element (TRE), where overexpression of a variety of PKC isozymes results in enhanced activation by TPA, activation of NF-kappa B by TPA is not enhanced by overexpression of PKC isozymes such as cPKC alpha, nPKC delta, or nPKC theta. However, the overexpression of nPKC epsilon does result in enhancement. A kinase-negative point mutant of nPKC epsilon, where Lys at the ATP binding site is altered to Arg, does not cause this enhancement of NF-kappa B activation. Further, the kinase-negative nPKC epsilon partially suppresses endogenous NF-kappa B activity. These results suggest that nPKC epsilon is specifically involved in the activation of NF-kappa B when cells are treated with TPA.
Hirano
M
M
Department of Molecular Biology, Yokohama City University School of Medicine, Japan.
Hirai
S
S
Mizuno
K
K
Osada
S
S
Hosaka
M
M
Ohno
S
S
D000818:Animals; D015153:Blotting, Western; D002460:Cell Line; D015500:Chloramphenicol O-Acetyltransferase / Q000096:biosynthesis; D005347:Fibroblasts; D007527:Isoenzymes / Q000378:metabolism*; D008156:Luciferases / Q000096:biosynthesis; D016328:NF-kappa B / Q000096:biosynthesis*; D010957:Plasmids; D017354:Point Mutation; D011493:Protein Kinase C / Q000378:metabolism*; D051381:Rats; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D014162:Transfection
D007527:Isoenzymes; D016328:NF-kappa B; D011994:Recombinant Proteins; D008156:Luciferases; D015500:Chloramphenicol O-Acetyltransferase; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate