Essential role of protein kinase C zeta in the impairment of insulin-induced glucose transport in IRS-2-deficient brown adipocytes

FEBS Lett. 2003 Feb 11;536(1-3):161-6. doi: 10.1016/s0014-5793(03)00049-8.

Abstract

Insulin receptor substrate-2-deficient (IRS-2(-/-)) mice develop type 2 diabetes. We have investigated the molecular mechanisms by which IRS-2(-/-) immortalized brown adipocytes showed an impaired response to insulin in inducing GLUT4 translocation and glucose uptake. IRS-2-associated phosphatidylinositol 3-kinase (PI 3-kinase) activity was blunted in IRS-2(-/-) cells, total PI 3-kinase activity being reduced by 30%. Downstream, activation of protein kinase C (PKC) zeta was abolished in IRS-2(-/-) cells. Reconstitution with retroviral IRS-2 restores IRS-2/PI 3-kinase/PKC zeta signalling, as well as glucose uptake. Wild-type cells expressing a kinase-inactive mutant of PKC zeta lack GLUT4 translocation and glucose uptake. Our results support the essential role played by PKC zeta in the insulin resistance and impaired glucose uptake observed in IRS-2-deficient brown adipocytes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adipocytes / drug effects
  • Adipocytes / enzymology
  • Adipocytes / metabolism*
  • Adipose Tissue, Brown / cytology
  • Animals
  • Biological Transport
  • Cells, Cultured
  • Glucose / metabolism*
  • Insulin / pharmacology*
  • Insulin Receptor Substrate Proteins
  • Intracellular Signaling Peptides and Proteins
  • Mice
  • Mice, Knockout
  • Phosphatidylinositol 3-Kinases / metabolism
  • Phosphoproteins / genetics
  • Phosphoproteins / physiology*
  • Phosphorylation
  • Protein Kinase C / physiology*
  • Signal Transduction

Substances

  • Insulin
  • Insulin Receptor Substrate Proteins
  • Intracellular Signaling Peptides and Proteins
  • Irs2 protein, mouse
  • Phosphoproteins
  • Phosphatidylinositol 3-Kinases
  • protein kinase C zeta
  • Protein Kinase C
  • Glucose