Phosphorylation of protein synthesis initiation factor-2. Identification of the site in the alpha-subunit phosphorylated in reticulocyte lysates.
The data presented here show that serine-51 of the alpha-subunit of eukaryotic initiation factor eIF-2 is the only residue phosphorylated by the eIF-2 alpha-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-2 alpha in whole cells and their extracts has been developed, and used to study the site(s) in eIF-2 alpha 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 alpha-subunit was obtained with the lysates and conditions used here.
Price
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NT
Department of Biochemistry, School of Medical Sciences, University of Bristol, U.K.
Proud
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CG
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D015852:Eukaryotic Initiation Factor-2 / Q000302:isolation & purification / Q000378:metabolism*; D008969:Molecular Sequence Data; D010449:Peptide Mapping; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism; D012313:RNA / Q000378:metabolism; D012156:Reticulocytes / Q000378:metabolism*; D012694:Serine / Q000378:metabolism*; D014357:Trypsin; D019892:eIF-2 Kinase
D015852:Eukaryotic Initiation Factor-2; D012694:Serine; D012313:RNA; D011494:Protein Kinases; D019892:eIF-2 Kinase; D014357:Trypsin