Phorbol ester and insulin stimulate protein kinase C isoforms in rat adipocytes

Diabetes Res Clin Pract. 1994 Dec 16;26(2):91-9. doi: 10.1016/0168-8227(94)90145-7.

Abstract

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.

MeSH terms

  • Adipocytes / drug effects
  • Adipocytes / enzymology*
  • Adipocytes / ultrastructure
  • Animals
  • Biological Transport / drug effects
  • Biological Transport / physiology
  • Calcium / physiology
  • Cell Membrane / enzymology
  • Cell Membrane / ultrastructure
  • Cytosol / enzymology
  • Cytosol / ultrastructure
  • Immunoblotting
  • Insulin / pharmacology*
  • Isoenzymes / metabolism*
  • Isoenzymes / physiology
  • Male
  • Protein Kinase C / metabolism*
  • Protein Kinase C / physiology
  • Rats
  • Rats, Wistar
  • Tetradecanoylphorbol Acetate / pharmacology*

Substances

  • Insulin
  • Isoenzymes
  • Protein Kinase C
  • Tetradecanoylphorbol Acetate
  • Calcium