Insulin and insulin-like growth factor I receptors: similarities and differences in signal transduction

Horm Res. 2001;55 Suppl 2:22-6. doi: 10.1159/000063469.


The insulin receptor (IR) and the insulin-like growth factor I receptor (IGF-IR) belong to the same subfamily of receptor tyrosine kinases with two extracellular alpha-subunits and two transmembrane beta-subunits. They share a high similarity of structure and intracellular signalling events. However, the IR and the IGF-IR mediate different effects on metabolism, cell proliferation, apoptosis and differentiation. Although some of the variation can be attributed to a different tissue distribution or subcellular localization, it can also be explained by structural differences in the beta-subunit, which may result in activation of specific substrates and signal pathways.

Publication types

  • Review

MeSH terms

  • Animals
  • Receptor, IGF Type 1 / physiology*
  • Receptor, Insulin / physiology*
  • Signal Transduction / physiology*
  • Structure-Activity Relationship


  • Receptor, IGF Type 1
  • Receptor, Insulin