Interaction of insulin receptor substrate-2 (IRS-2) with the insulin and insulin-like growth factor I receptors. Evidence for two distinct phosphotyrosine-dependent interaction domains within IRS-2

J Biol Chem. 1996 May 17;271(20):11641-5. doi: 10.1074/jbc.271.20.11641.

Abstract

Insulin receptor substrate 2 (IRS-2) has recently been shown to be a substrate of the insulin receptor (IR). In this study we utilize the yeast two-hybrid system and assays of in vitro interaction to demonstrate that IRS-2 interacts directly with the IR and the insulin-like growth factor I receptor. We show that, like IRS-1, the region of IRS-2 that contains the putative phosphotyrosine binding and SAIN elements (188-591) is sufficient for receptor interaction and that this interaction is dependent upon the NPX(p)Y (where (p)Y is phosphotyrosine) motifs within the juxtamembrane domains of the receptors. In addition to this amino-terminal NPX(p)Y-binding domain, an additional domain of strong interaction was identified in the central region of IRS-2 and was localized between amino acids 591 and 733. This interaction was found to be dependent upon receptor phosphorylation but was NPX(p)Y-independent. This region does not appear to have either an SH2 or a phosphotyrosine binding domain. Both of the interactions could also be demonstrated in vitro using IRS-2 glutathione S-transferase fusion proteins. We conclude that IRS-2, unlike IRS-1, can interact with tyrosine-phosphorylated receptors such as the IR and insulin-like growth factor I receptor via multiple independent binding motifs. Our findings suggest the existence of a previously unidentified phosphotyrosine-dependent binding domain within the central region of IRS-2.

Publication types

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

MeSH terms

  • Animals
  • Binding Sites
  • CHO Cells
  • Cricetinae
  • Insulin Receptor Substrate Proteins
  • Intracellular Signaling Peptides and Proteins
  • Phosphoproteins / chemistry*
  • Phosphotyrosine / chemistry*
  • Receptor, IGF Type 1 / chemistry*
  • Receptor, Insulin / chemistry*
  • Structure-Activity Relationship

Substances

  • Insulin Receptor Substrate Proteins
  • Intracellular Signaling Peptides and Proteins
  • Phosphoproteins
  • Phosphotyrosine
  • Receptor, IGF Type 1
  • Receptor, Insulin