Regulated translation initiation controls stress-induced gene expression in mammalian cells.
Protein kinases that phosphorylate the alpha subunit of eukaryotic initiation factor 2 (eIF2alpha) are activated in stressed cells and negatively regulate protein synthesis. Phenotypic analysis of targeted mutations in murine cells reveals a novel role for eIF2alpha kinases in regulating gene expression in the unfolded protein response (UPR) and in amino acid starved cells. When activated by their cognate upstream stress signals, the mammalian eIF2 kinases PERK and GCN2 repress translation of most mRNAs but selectively increase translation of Activating Transcription Factor 4 (ATF4), resulting in the induction of the downstream gene CHOP (GADD153). This is the first example of a mammalian signaling pathway homologous to the well studied yeast general control response in which eIF2alpha phosphorylation activates genes involved in amino acid biosynthesis. Mammalian cells thus utilize an ancient pathway to regulate gene expression in response to diverse stress signals.
Harding
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HP
Skirball Institute of Biomolecular Medicine The Department of Medicine, Kaplan Cancer Center New York University School of Medicine, New York, NY 10016, USA.
Novoa
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Zhang
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Zeng
H
H
Wek
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Schapira
M
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Ron
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D051701:Activating Transcription Factor 4; D000596:Amino Acids / Q000096:biosynthesis / Q000172:deficiency* / Q000235:genetics; D000818:Animals; D022762:CCAAT-Enhancer-Binding Proteins / Q000235:genetics; D002352:Carrier Proteins / Q000378:metabolism; D002460:Cell Line; D006224:Cricetinae; D004721:Endoplasmic Reticulum / Q000378:metabolism; D000091342:Endoplasmic Reticulum Chaperone BiP; D015852:Eukaryotic Initiation Factor-2 / Q000737:chemistry / Q000378:metabolism; D005786:Gene Expression Regulation; D006360:Heat-Shock Proteins; D008322:Mammals / Q000235:genetics*; D051379:Mice; D018832:Molecular Chaperones / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D010442:Peptide Chain Initiation, Translational; D010766:Phosphorylation; D011489:Protein Denaturation; D017510:Protein Folding; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D012270:Ribosomes / Q000378:metabolism; D015398:Signal Transduction; D051742:Transcription Factor CHOP; D014157:Transcription Factors / Q000096:biosynthesis / Q000235:genetics; D019892:eIF-2 Kinase / Q000235:genetics / Q000378:metabolism*
D051701:Activating Transcription Factor 4; D000596:Amino Acids; D022762:CCAAT-Enhancer-Binding Proteins; D002352:Carrier Proteins; D000091342:Endoplasmic Reticulum Chaperone BiP; D015852:Eukaryotic Initiation Factor-2; D006360:Heat-Shock Proteins; D018832:Molecular Chaperones; D011494:Protein Kinases; D017346:Protein Serine-Threonine Kinases; D012333:RNA, Messenger; D051742:Transcription Factor CHOP; D014157:Transcription Factors; D019892:eIF-2 Kinase; C497110:Atf4 protein, rat; C497250:Ddit3 protein, mouse; C497251:Ddit3 protein, rat; C070634:Eif2ak4 protein, mouse