The accumulation of unfolded protein in the endoplasmic reticulum (ER) attenuates protein synthesis initiation through phosphorylation of the alpha subunit of eukaryotic translation initiation factor 2 (eIF2alpha) at Ser51. Subsequently, transcription of genes encoding adaptive functions including the glucose-regulated proteins is induced. We show that eIF2alpha phosphorylation is required for translation attenuation, transcriptional induction, and survival in response to ER stress. Mice with a homozygous mutation at the eIF2alpha phosphorylation site (Ser51Ala) died within 18 hr after birth due to hypoglycemia associated with defective gluconeogenesis. In addition, homozygous mutant embryos and neonates displayed a deficiency in pancreatic beta cells. The results demonstrate that regulation of translation through eIF2alpha phosphorylation is essential for the ER stress response and in vivo glucose homeostasis.
Pubmed ID: 11430820 RIS Download
Mesh terms: Activating Transcription Factors | Animals | Animals, Newborn | Blood Proteins | CCAAT-Enhancer-Binding Proteins | Carrier Proteins | Cell Survival | DNA-Binding Proteins | Endoplasmic Reticulum | Gene Expression | Germ-Line Mutation | Gluconeogenesis | Glucose | Heat-Shock Proteins | Homeostasis | Homozygote | Hypoglycemia | Islets of Langerhans | Mice | Mice, Mutant Strains | Molecular Chaperones | Mutagenesis | Phosphorylation | Protein Biosynthesis | Protein Folding | RNA, Messenger | Transcription Factor CHOP | Transcription Factors | Transcriptional Activation
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