Transdominant inhibition of tyrosine kinase activity in mutant insulin/insulin-like growth factor I hybrid receptors

Judith L. Treadway, Brian D. Morrison, Maria A. Soos, Kenneth Siddle, Jerrold Olefsky, Axel Ullrich, Donald A. Mcclain, Jeffrey E. Pessin

Research output: Contribution to journalArticle

78 Scopus citations

Abstract

Classical insulin and insulin-like growth factor I (IGF-I) receptors exist as well defined α2β2 heterotetrameric complexes that are assembled from two identical αβ heterodimeric half-receptor precursors. Recent evidence suggests that insulin and IGF-I half-receptors can heterologously assemble to form α2β2 insulin/IGF-I hybrid receptor complexes in vivo and in vitro. We have utilized hybrid receptor complexes to examine ligand-stimulated transmembrane signaling of wild-type insulin (αβINS.WT) or IGF-I (αβIGF.WT) half-receptors assembled with a kinase-defective insulin half-receptor mutant (αβINS.A/K). In vitro assembly of either (αβ)IGF.WT/(αβ)INS.A/K or (αβ)INS.WT/(αβ)INS.A/K hybrid receptors resulted in decreased substrate protein kinase activity. The degree of protein kinase inactivation directly correlated with the amount of immunologically cross-reactive hybrid receptors formed. In contrast to substrate kinase activity, insulin-stimulated autophosphorylation of the (αβ)INS.WT/(αβ)INS.A/K hybrid receptor complex was completely unaffected in comparison to the wild-type (αβ)INS.WT/(αβ)INS.WT receptor. To assess a molecular basis for this difference, autophosphorylation of a hybrid receptor composed of a truncated β-subunit insulin half-receptor with the kinase-defective half-receptor, (αβ)INS.ΔCT/ (αβ)INS.A/K, demonstrated the exclusive autophosphorylation of the (αβ)INS.A/K half-receptor β subunit. These results demonstrate that ligand-dependent substrate phosphorylation by insulin and IGF-I holoreceptors requires interactions between two functional β subunits within the α2β2 heterotetrameric complex and occurs through an intramolecular trans-phosphorylation reaction.

Original languageEnglish (US)
Pages (from-to)214-218
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Volume88
Issue number1
DOIs
StatePublished - Jan 1 1991
Externally publishedYes

    Fingerprint

Keywords

  • Autophosphorylation
  • Heterologous receptors
  • In vitro assembly
  • Substrate phosphorylation

ASJC Scopus subject areas

  • General

Cite this