Insulin-stimulated phosphorylation of initiation factor 4E is mediated by the MAP kinase pathway

Andrea Flynn, Christopher G. Proud

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70 Citations (Scopus)


The cap-binding initiation factor 4E (eIF4E) is regulated by phosphorylation and by the inhibitory binding protein 4E-BP1. Here we show that insulin-induced phosphorylation of eIF4E is not significantly affected by rapamycin, but is sensitive to wortmannin, which inhibits phosphatidylinositol 3'-kinase and blocks the activation of MAP kinase. Since PD098058, an inhibitor of MAP kinase activation, also blocks insulin-induced phosphorylation of eIF4E, the IMAP kinase pathway seems to mediate this effect. Phosphorylated eIF4E can still bind to 4E-BP1. These data illustrate that (i) distinct signalling pathways mediate the phosphorylation of eIF4E and 4E-BP1 and (ii) phosphorylation of eIF4E, unlike that of 4E-BP1, does not lead directly to the release of 4E-BP1.

Original languageEnglish
Pages (from-to)162-166
Number of pages5
JournalFEBS Letters
Issue number2
Publication statusPublished or Issued - 1 Jul 1996


  • Insulin
  • MAP kinase
  • Rapamycin
  • Translation
  • eIF

ASJC Scopus subject areas

  • Biophysics
  • Structural Biology
  • Biochemistry
  • Molecular Biology
  • Genetics
  • Cell Biology

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