Insulin activates phospholipase C-gamma1 via a PI-3 kinase dependent mechanism in 3T3-L1 adipocytes

Biochem Biophys Res Commun. 2001 Mar 30;282(2):615-20. doi: 10.1006/bbrc.2001.4616.

Abstract

Previously we have shown that the insulin receptor and phospholipase C-gamma1 physically interact in the 3T3-L1 adipocyte cell line. In this study, we investigated the ability of insulin and PDGF to stimulate PLC-gamma1 enzyme activity as measured by PI-(4,5)P(2) hydrolysis. Both insulin and PDGF caused a rapid (<1 min) increase in PLC activity associated with the respective receptor. PDGF treatment resulted in a higher and more sustained stimulation of PLC-gamma1 activity compared to insulin (0.95 pmol/min/mg vs 0.68 pmol/min/mg). Furthermore, insulin and PDGF promoted increases in total cellular DAG, one of the products of PI-(4,5)P(2) hydrolysis. Insulin-stimulated PLC activity appears to be downstream of PI-3Kinase as the DAG increase was partially blocked by Wortmannin and addition of PI-(3,4,5)P(3) activated PLC-gamma1 in vitro. Inhibition of PLC using U73122 or an inhibitory peptide caused a decrease in insulin-stimulated 2-deoxyglucose transport and GLUT4 translocation that was rescued by the addition of OAG, a cell-permeable synthetic DAG.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • 3T3 Cells
  • Adipocytes / drug effects*
  • Adipocytes / enzymology*
  • Adipocytes / metabolism
  • Animals
  • Biological Transport, Active / drug effects
  • Diglycerides / biosynthesis
  • Diglycerides / pharmacology
  • Enzyme Activation / drug effects
  • Estrenes / pharmacology
  • Glucose / metabolism
  • Glucose Transporter Type 1
  • Glucose Transporter Type 4
  • Insulin / pharmacology*
  • Isoenzymes / antagonists & inhibitors
  • Isoenzymes / metabolism*
  • Mice
  • Monosaccharide Transport Proteins / metabolism
  • Muscle Proteins*
  • Phosphatidylinositol 3-Kinases / metabolism*
  • Phosphatidylinositol 4,5-Diphosphate / metabolism
  • Phospholipase C gamma
  • Platelet-Derived Growth Factor / pharmacology
  • Pyrrolidinones / pharmacology
  • Type C Phospholipases / antagonists & inhibitors
  • Type C Phospholipases / metabolism*

Substances

  • Diglycerides
  • Estrenes
  • Glucose Transporter Type 1
  • Glucose Transporter Type 4
  • Insulin
  • Isoenzymes
  • Monosaccharide Transport Proteins
  • Muscle Proteins
  • Phosphatidylinositol 4,5-Diphosphate
  • Platelet-Derived Growth Factor
  • Pyrrolidinones
  • Slc2a4 protein, mouse
  • 1-(6-((3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione
  • Phosphatidylinositol 3-Kinases
  • Type C Phospholipases
  • Phospholipase C gamma
  • Glucose