An integrated stress response regulates amino acid metabolism and resistance to oxidative stress.
Eukaryotic cells respond to unfolded proteins in their endoplasmic reticulum (ER stress), amino acid starvation, or oxidants by phosphorylating the alpha subunit of translation initiation factor 2 (eIF2alpha). This adaptation inhibits general protein synthesis while promoting translation and expression of the transcription factor ATF4. Atf4(-/-) cells are impaired in expressing genes involved in amino acid import, glutathione biosynthesis, and resistance to oxidative stress. Perk(-/-) cells, lacking an upstream ER stress-activated eIF2alpha kinase that activates Atf4, accumulate endogenous peroxides during ER stress, whereas interference with the ER oxidase ERO1 abrogates such accumulation. A signaling pathway initiated by eIF2alpha phosphorylation protects cells against metabolic consequences of ER oxidation by promoting the linked processes of amino acid sufficiency and resistance to oxidative stress.
Harding
Heather P
HP
Skirball Institute, New York University School of Medicine, New York, NY 10016, USA.
Zhang
Yuhong
Y
Zeng
Huiquing
H
Novoa
Isabel
I
Lu
Phoebe D
PD
Calfon
Marcella
M
Sadri
Navid
N
Yun
Chi
C
Popko
Brian
B
Paules
Richard
R
Stojdl
David F
DF
Bell
John C
JC
Hettmann
Thore
T
Leiden
Jeffrey M
JM
Ron
David
D
D051701:Activating Transcription Factor 4; D000596:Amino Acids / Q000378:metabolism*; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D015152:Blotting, Northern; D017173:Caenorhabditis elegans; D002455:Cell Division; D002469:Cell Separation; D003574:Cytochrome c Group / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004721:Endoplasmic Reticulum / Q000378:metabolism; D015852:Eukaryotic Initiation Factor-2 / Q000737:chemistry / Q000378:metabolism*; D005347:Fibroblasts / Q000378:metabolism; D005434:Flow Cytometry; D005838:Genotype; D005978:Glutathione / Q000378:metabolism; D015151:Immunoblotting; D051379:Mice; D008856:Microscopy, Fluorescence; D009154:Mutation; D018384:Oxidative Stress; D009195:Peroxidase / Q000378:metabolism; D010766:Phosphorylation; D011233:Precipitin Tests; D013997:Time Factors; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014415:Tunicamycin / Q000494:pharmacology; D015854:Up-Regulation
D000596:Amino Acids; D000900:Anti-Bacterial Agents; D003574:Cytochrome c Group; D015852:Eukaryotic Initiation Factor-2; D014157:Transcription Factors; D014415:Tunicamycin; D051701:Activating Transcription Factor 4; D009195:Peroxidase; D005978:Glutathione