Interferon-α-induced phosphorylation and activation of cytosolic phospholipase A2 is required for the formation of interferon-stimulated gene factor three

Vincenzo Flati, S. Jaharul Haque, Bryan R.G. Williams

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Treatment of cells with interferon (IFN)-α caused phosphorylation and activation of cytosolic phospholipase A2 (cPLA2). The protein tyrosine kinase Jak1 was found to be necessary for the activation of cPLA2. Jak1 could be co-immunoprecipitated with cPLA2 from cell extracts, indicating that a close physical interaction occurs between these two proteins. The induction of IFN-stimulated gene factor three (ISGF3) by IFN-α, is blocked by cPLA2 inhibitors in cell cultures and in cell-free reconstituted systems. However, these inhibitors do not block IFN-α- or γ-induced binding of STAT1 to the inverted repeat (IR) element of the IFN regulatory factor 1 (IRF-1) gene. Thus, cPLA2 activation occurs as an early event in the IFN-α response and is selectively involved in ISGF3-dependent gene activation.

Original languageEnglish
Pages (from-to)1566-1571
Number of pages6
JournalThe EMBO Journal
Issue number7
Publication statusPublished - 1 Apr 1996
Externally publishedYes


  • Interferon
  • JAKs
  • Phospholipase A
  • Signal transduction
  • STATs

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