Phosphorylation of protein synthesis initiation factor-2. Identification of the site in the α-subunit phosphorylated in reticulocyte lysates

Nigel T. Price, Christopher G. Proud

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The data presented here show that serine-51 of the α-subunit of eukaryotic initiation factor eIF-2 is the only residue phosphorylated by the eIF-2α-specific kinases HCR (haem-controlled repressor) and dsI (double-stranded RNA-activated inhibitor) in vitro. This confirms our earlier finding that serine-48 is not labelled by either kinase. Methodology appropriate for the examination of phosphorylation sites in eIF-2α in whole cells and their extracts has been developed, and used to study the site(s) in eIF-2α labelled in reticulocyte lysates. Only serine-51 became phosphorylated under conditions of haem-deficiency or in the presence of double-stranded RNA. No evidence for a second phosphorylation site on the α-subunit was obtained with the lysates and conditions used here.

Original languageEnglish
Pages (from-to)83-88
Number of pages6
JournalBBA - Molecular Cell Research
Issue number1
Publication statusPublished - 13 Aug 1990
Externally publishedYes


  • Initiation factor 2
  • Protein phosphorylation
  • Protein synthesis

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology

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