Regulation of IRS-1/SHP2 interaction and AKT phosphorylation in animal models of insulin resistance

Endocrine. 2002 Jun;18(1):1-12. doi: 10.1385/ENDO:18:1:01.

Abstract

Insulin stimulates tyrosine kinase activity of its receptor, resulting in phosphorylation of its cytosolic substrate, insulin receptor substrate-1, which, in turn, associates with proteins containing SH2 domains, including phosphatidylinositol 3-kinase (PI 3-kinase) and the phosphotyrosine phosphatase SHP2. The regulation of these associations in situations of altered insulin receptor substrate-1 (IRS-1) phosphorylation was not yet investigated. In the present study, we investigated insulin-induced IRS-1/SHP2 and IRS-1/PI 3-kinase associations and the regulation of a downstream serine-kinase AKT/PKB in liver and muscle of three animal models of insulin resistance: STZ diabetes, epinephrine-treated rats, and aging, which have alterations in IRS-1 tyrosine phosphorylation in common. The results demonstrated that insulin-induced IRS-1/PI 3-kinase association has a close correlation with IRS-1 tyrosine phosphorylation levels, but insulin-induced IRS-1/SHP2 association showed a modulation that did not parallel IRS-1 phosphorylation, with a tissue-specific regulation in aging. The integration of the behavior of IRS-1/PI 3-kinase and with IRS-1/SHP2 associations may be important for insulin signaling downstream as AKT phosphorylation. In conclusion, the results of the present study demonstrated that insulin-induced IRS-1/SHP2 association can be regulated in insulin-sensitive tissues of animal models of insulin resistance and may have a role in the control of AKT phosphorylation, which may be implicated in the control of glucose metabolism.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aging
  • Animals
  • Diabetes Mellitus, Experimental / metabolism
  • Disease Models, Animal*
  • Epinephrine / pharmacology
  • Insulin / pharmacology
  • Insulin Receptor Substrate Proteins
  • Insulin Resistance*
  • Liver / drug effects
  • Liver / metabolism
  • Male
  • Muscle, Skeletal / drug effects
  • Muscle, Skeletal / metabolism
  • Phosphatidylinositol 3-Kinases / metabolism*
  • Phosphoproteins / metabolism*
  • Phosphorylation
  • Phosphotyrosine / metabolism
  • Protein Serine-Threonine Kinases*
  • Protein Tyrosine Phosphatases / metabolism*
  • Proto-Oncogene Proteins / metabolism*
  • Proto-Oncogene Proteins c-akt
  • Rats
  • Rats, Wistar

Substances

  • Insulin
  • Insulin Receptor Substrate Proteins
  • Irs1 protein, rat
  • Phosphoproteins
  • Proto-Oncogene Proteins
  • Phosphotyrosine
  • Akt1 protein, rat
  • Protein Serine-Threonine Kinases
  • Proto-Oncogene Proteins c-akt
  • Protein Tyrosine Phosphatases
  • Epinephrine