Phorbol ester and insulin stimulate protein kinase C isoforms in rat adipocytes.
We examined effect of insulin or 12-O-tetradecanoyl phorbol 13-acetate (TPA) on the subcellular redistribution of protein kinase C isoforms in rat adipocytes. Total Mono Q column-elutable novel PKCs (nPKCs) which are Ca(2+)-independent and phospholipid-dependent protein kinases, decreased in the cytosolic fraction and increased in the membrane fraction during treatment with insulin or phorbol ester for 10 min. Immunoblot analysis of novel PKCs, -epsilon, -delta and -zeta, showed that insulin stimulated the translocation of these PKC isoforms from cytosol to membrane, similar to the translocation of conventional Ca2+/phospholipid-dependent PKCs (cPKCs), -alpha, -beta, and -gamma. Phorbol esters stimulated the translocation of PKC-alpha, -beta, -gamma, -epsilon and -delta, but not PKC-zeta. These results suggest that (a) insulin and phorbol esters similarly stimulate the translocation of each PKC isoform except for PKC-zeta, and (b) the translocation of both nPKCs and cPKCs occurs during insulin and TPA actions in rat adipocytes.
Ishizuka
T
T
Third Department of Internal Medicine, Gifu University School of Medicine, Japan.
Yamamoto
M
M
Kajita
K
K
Nagashima
T
T
Taniguchi
O
O
Wada
H
H
Itaya
S
S
Yasuda
K
K
D017667:Adipocytes / Q000187:drug effects / Q000201:enzymology* / Q000648:ultrastructure; D000818:Animals; D001692:Biological Transport / Q000187:drug effects / Q000502:physiology; D002118:Calcium / Q000502:physiology; D002462:Cell Membrane / Q000201:enzymology / Q000648:ultrastructure; D003600:Cytosol / Q000201:enzymology / Q000648:ultrastructure; D015151:Immunoblotting; D007328:Insulin / Q000494:pharmacology*; D007527:Isoenzymes / Q000378:metabolism* / Q000502:physiology; D008297:Male; D011493:Protein Kinase C / Q000378:metabolism* / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*
D007328:Insulin; D007527:Isoenzymes; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium