Phosphorylation of initiation factor 2 alpha by protein kinase GCN2 mediates gene-specific translational control of GCN4 in yeast.
We show that phosphorylation of the alpha subunit of eukaryotic translation initiation factor 2 (eIF-2) by the protein kinase GCN2 mediates translational control of the yeast transcriptional activator GCN4. In vitro, GCN2 specifically phosphorylates the alpha subunit of rabbit or yeast eIF-2. In vivo, phosphorylation of eIF-2 alpha increases in response to amino acid starvation, which is dependent on GCN2. Substitution of Ser-51 with alanine eliminates phosphorylation of eIF-2 alpha by GCN2 in vivo and in vitro and abolishes increased expression of GCN4 and amino acid biosynthetic genes under its control in amino acid-starved cells. The Asp-51 substitution mimics the phosphorylated state and derepresses GCN4 in the absence of GCN2. Thus, an established mechanism for regulating total protein synthesis in mammalian cells mediates gene-specific translational control in yeast.
Dever
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Section on Molecular Genetics of Lower Eukaryotes, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892.
Feng
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Wek
R C
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Cigan
A M
AM
Donahue
T F
TF
Hinnebusch
A G
AG
D000818:Animals; D001483:Base Sequence; D004252:DNA Mutational Analysis; D004268:DNA-Binding Proteins; D005656:Fungal Proteins / Q000235:genetics*; D006801:Humans; D007231:Infant, Newborn; D008957:Models, Genetic; D008969:Molecular Sequence Data; D015345:Oligonucleotide Probes; D016366:Open Reading Frames; D010448:Peptide Initiation Factors / Q000378:metabolism*; D010766:Phosphorylation; D010957:Plasmids; D039881:Prokaryotic Initiation Factor-2; D014176:Protein Biosynthesis; D011494:Protein Kinases / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases; D011817:Rabbits; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins; D012694:Serine; D014157:Transcription Factors / Q000235:genetics*
D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D015345:Oligonucleotide Probes; D010448:Peptide Initiation Factors; D039881:Prokaryotic Initiation Factor-2; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D012694:Serine; D011494:Protein Kinases; C512912:GCN2 protein, S cerevisiae; D017346:Protein Serine-Threonine Kinases