Insulin-like effects of sodium orthovanadate on diacylglycerol-protein kinase C signaling in BC3H-1 myocytes.
In this paper we examine whether sodium orthovanadate activates diacylglycerol (DAG)/protein kinase C (PKC) signaling systems that are activated by insulin in BC3H-1 myocytes. Like insulin, sodium orthovanadate provoked increases in membrane DAG, PKC enzyme activity, and immunoreactive PKC-beta. Concomitantly, both PKC enzyme activity and immunoreactive PKC-beta decreased in the cytosol, suggesting that sodium orthovanadate, like insulin, stimulated the translocation of PKC-beta from the cytosol to the membrane fraction. Sodium orthovanadate was also found to activate phospholipid signaling pathways that were previously reported to be activated by insulin, viz., inositol-lipid synthesis/turnover; phosphatidylcholine hydrolysis; and de novo phospholipid synthesis by activation of glycerol-3-PO4 acyltransferase. Our findings suggest that vanadate mimics insulin in the activation of specific phospholipid/DAG/PKC signaling pathways.
J. A. Haley Veterans' Hospital, University of South Florida College of Medicine, Tampa 33612.
K
K
Yamada
M L
ML
Standaert
B
B
Yu
H
H
Mischak
D R
DR
Cooper
R V
RV
Farese
D000818:Animals; D001692:Biological Transport; D002458:Cell Fractionation; D003600:Cytosol / Q000201:enzymology; D004075:Diglycerides / Q000378:metabolism*; D004789:Enzyme Activation; D005992:Glycerol-3-Phosphate O-Acyltransferase / Q000378:metabolism; D007328:Insulin / Q000494:pharmacology*; D007527:Isoenzymes / Q000378:metabolism; D008566:Membranes / Q000201:enzymology; D051379:Mice; D009132:Muscles / Q000187:drug effects*; D010743:Phospholipids / Q000378:metabolism; D011493:Protein Kinase C / Q000378:metabolism*; D015398:Signal Transduction; D014638:Vanadates / Q000494:pharmacology*
D004075:Diglycerides; D007328:Insulin; D007527:Isoenzymes; D010743:Phospholipids; D014638:Vanadates; D005992:Glycerol-3-Phosphate O-Acyltransferase; D011493:Protein Kinase C