Potential role of protein kinase B in glucose transporter 4 translocation in adipocytes

Endocrinology. 1997 May;138(5):2005-10. doi: 10.1210/endo.138.5.5136.

Abstract

Phosphatidylinositol 3-kinase (PI 3-kinase) activation promotes glucose transporter 4 (Glut 4) translocation in adipocytes. In this study, we demonstrate that protein kinase B, a serine/threonine kinase stimulated by PI 3-kinase, is activated by both insulin and okadaic acid in isolated adipocytes, in parallel with their effects on Glut 4 translocation. In 3T3-L1 adipocytes, platelet-derived growth factor activated PI 3-kinase as efficiently as insulin but was only half as potent as insulin in promoting protein kinase B (PKB) activation. To look for a potential role of PKB in Glut 4 translocation, adipocytes were transfected with a constitutively active PKB (Gag-PKB) together with an epitope tagged transporter (Glut 4 myc). Gag-PKB was associated with all membrane fractions, whereas the endogenous PKB was mostly cytosolic. Expression of Gag-PKB led to an increase in Glut 4 myc amount at the cell surface. Our results suggest that PKB could play a role in promoting Glut 4 appearance at the cell surface following exposure of adipocytes to insulin and okadaic acid stimulation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adipocytes / metabolism*
  • Animals
  • Biological Transport
  • Enzyme Activation / drug effects
  • Glucose Transporter Type 4
  • Immunoblotting
  • Immunosorbent Techniques
  • Insulin / pharmacology
  • Male
  • Monosaccharide Transport Proteins / metabolism*
  • Muscle Proteins*
  • Okadaic Acid / pharmacology
  • Phosphatidylinositol 3-Kinases
  • Phosphotransferases (Alcohol Group Acceptor) / metabolism
  • Platelet-Derived Growth Factor / pharmacology
  • Protein-Serine-Threonine Kinases*
  • Proto-Oncogene Proteins / genetics
  • Proto-Oncogene Proteins / metabolism*
  • Proto-Oncogene Proteins c-akt
  • Rats
  • Rats, Wistar
  • Transfection

Substances

  • Glucose Transporter Type 4
  • Insulin
  • Monosaccharide Transport Proteins
  • Muscle Proteins
  • Platelet-Derived Growth Factor
  • Proto-Oncogene Proteins
  • Slc2a4 protein, rat
  • Okadaic Acid
  • Phosphatidylinositol 3-Kinases
  • Phosphotransferases (Alcohol Group Acceptor)
  • Protein-Serine-Threonine Kinases
  • Proto-Oncogene Proteins c-akt