Differential down-regulation of insulin-sensitive protein kinase-C isoforms by 12-O-tetradecanoylphorbol-13-acetate in rat adipocytes and BC3H-1 myocytes.
In rat adipocytes, chronic incubation with 12-O-tetradecanoylphorbol-13-acetate (TPA) reduced immunoreactive protein kinase-C (PKC) beta, gamma, delta, and zeta isoforms by 40-60% and PKC alpha by 75%, but had little effect on PKC epsilon levels. In BC3H-1 myocytes, chronic TPA treatment had no effect on PKC beta, increased PKC zeta, and depleted PKC alpha. Acute treatment with insulin induced the translocation of PKC beta in the myocytes both before and after chronic TPA treatment, but had no acute effect on the alpha or zeta isoforms. In contrast, acute TPA treatment in the myocytes had little effect on PKC beta, but induced the rapid translocation of alpha and zeta. The differential effects of chronic TPA treatment on the down-regulation of PKC beta may explain why insulin continues to activate biological processes in TPA-treated BC3H-1 myocytes, but not in adipocytes.
Standaert
M L
ML
Research Service, J. A. Haley V.A. Hospital, Tampa, Florida 33612.
Cooper
D R
DR
Hernandez
H
H
Arnold
T P
TP
Farese
R V
RV
D000273:Adipose Tissue / Q000187:drug effects / Q000201:enzymology*; D000818:Animals; D002460:Cell Line; D002462:Cell Membrane / Q000201:enzymology; D002478:Cells, Cultured; D003600:Cytosol / Q000201:enzymology; D007328:Insulin / Q000494:pharmacology*; D007527:Isoenzymes / Q000378:metabolism*; D007700:Kinetics; D008297:Male; D009132:Muscles / Q000187:drug effects / Q000201:enzymology*; D011493:Protein Kinase C / Q000378:metabolism*; D051381:Rats; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*
D007328:Insulin; D007527:Isoenzymes; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate