Insulin-dependent alterations of phorbol ester binding to adipocyte subcellular constituents. Evidence for the involvement of protein kinase C in insulin action.
The binding of tritiated phorbol-12,13-dibutyrate (3H-PBu2) was employed to estimate the mass of protein kinase C associated with plasma membranes and cytosol isolated from untreated and insulin-treated adipocytes. Binding of 3H-PBu2 to both plasma membranes and cytosol was rapid, achieving a steady state within minutes. Treatment of cells with physiological concentration of insulin (0.67 nM) caused a 42% increase (from 0.92 +/- 0.08 to 1.30 +/- 0.12 pmol 3H-PBu2/mg protein, p less than 0.0001) and a 27% decrease (from 0.41 +/- 0.07 to 0.30 +/- 0.05 pmol 3H-PBu2/mg protein, p less than 0.020) in phorbol ester bound to cytosol and plasma membranes, respectively. The half-maximal concentrations of unlabelled PBu2 needed to displace 3H-PBu2 bound to cytosol from control and insulin-treated cells were 54 and 13 pM, respectively. These data indicate that insulin modifies protein kinase C in adipocytes.
Pershadsingh
H A
HA
Shade
D L
DL
McDonald
J M
JM
D000273:Adipose Tissue / Q000378:metabolism*; D000818:Animals; D029742:Caenorhabditis elegans Proteins; D002273:Carcinogens / Q000378:metabolism; D002352:Carrier Proteins; D002462:Cell Membrane / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D007328:Insulin / Q000494:pharmacology*; D007700:Kinetics; D008297:Male; D015240:Phorbol 12,13-Dibutyrate; D010703:Phorbol Esters / Q000378:metabolism*; D011493:Protein Kinase C / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D011955:Receptors, Drug; D011971:Receptors, Immunologic / Q000187:drug effects / Q000378:metabolism*
D029742:Caenorhabditis elegans Proteins; D002273:Carcinogens; D002352:Carrier Proteins; D007328:Insulin; D010703:Phorbol Esters; D011955:Receptors, Drug; D011971:Receptors, Immunologic; C083141:phorbol ester binding protein; C027776:phorbol ester receptor; D015240:Phorbol 12,13-Dibutyrate; D011493:Protein Kinase C