Translational control is required for the unfolded protein response and in vivo glucose homeostasis.

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.

[1]  J. Lang.  Molecular mechanisms and regulation of insulin exocytosis as a paradigm of endocrine secretion. , 1999, European journal of biochemistry.

[2]  M. Rallison,et al.  Infancy-onset diabetes mellitus and multiple epiphyseal dysplasia. , 1972, The Journal of pediatrics.

[3]  T. W. Fawcett,et al.  Complexes containing activating transcription factor (ATF)/cAMP-responsive-element-binding protein (CREB) interact with the CCAAT/enhancer-binding protein (C/EBP)-ATF composite site to regulate Gadd153 expression during the stress response. , 1999, The Biochemical journal.

[4]  R. Hanson,et al.  Regulation of phosphoenolpyruvate carboxykinase (GTP) gene expression. , 1997, Annual review of biochemistry.

[5]  M. Schapira,et al.  Regulated translation initiation controls stress-induced gene expression in mammalian cells. , 2000, Molecular cell.

[6]  C. Samuel,et al.  The eIF-2 alpha protein kinases, regulators of translation in eukaryotes from yeasts to humans. , 1993, The Journal of biological chemistry.

[7]  Anne Bertolotti,et al.  Dynamic interaction of BiP and ER stress transducers in the unfolded-protein response , 2000, Nature Cell Biology.

[8]  William E. Balch,et al.  Integration of endoplasmic reticulum signaling in health and disease , 1999, Nature Medicine.

[9]  O. Bârzu,et al.  Determination of phosphoenolpyruvate carboxykinase activity with deoxyguanosine 5'-diphosphate as nucleotide substrate. , 1979, Analytical biochemistry.

[10]  Amy S. Lee.  Coordinated regulation of a set of genes by glucose and calcium ionophores in mammalian cells , 1987 .

[11]  T. Miyata,et al.  Homocysteine-respondent Genes in Vascular Endothelial Cells Identified by Differential Display Analysis , 1996, The Journal of Biological Chemistry.

[12]  Stephen S. Sternberg,et al.  Histology for Pathologists , 1992, Annals of Internal Medicine.

[13]  Junying Yuan,et al.  Caspase-12 mediates endoplasmic-reticulum-specific apoptosis and cytotoxicity by amyloid-β , 2000, Nature.

[14]  R. Kaufman,et al.  Ligand-independent Dimerization Activates the Stress Response Kinases IRE1 and PERK in the Lumen of the Endoplasmic Reticulum* , 2000, The Journal of Biological Chemistry.

[15]  D. Ron,et al.  Protein translation and folding are coupled by an endoplasmic-reticulum-resident kinase , 1999, Nature.

[16]  G. Darlington.  Molecular mechanisms of liver development and differentiation. , 1999, Current opinion in cell biology.

[17]  A. Leutz,et al.  Translational control of C/EBPalpha and C/EBPbeta isoform expression. , 2000, Genes & development.

[18]  R. Kaufman,et al.  Stress signaling from the lumen of the endoplasmic reticulum: coordination of gene transcriptional and translational controls. , 1999, Genes & development.

[19]  J. Sambrook,et al.  The presence of malfolded proteins in the endoplasmic reticulum signals the induction of glucose-regulated proteins , 1988, Nature.

[20]  R. Kaufman,et al.  The unfolded protein response , 2003, Journal of Cell Science.

[21]  G. Lathrop,et al.  EIF2AK3, encoding translation initiation factor 2-α kinase 3, is mutated in patients with Wolcott-Rallison syndrome , 2000, Nature Genetics.

[22]  Guy Plunkett,et al.  A new family of peptidyl-prolyl isomerases. , 1995, TIBS -Trends in Biochemical Sciences. Regular ed.

[23]  C. Thornton,et al.  Autopsy findings in the Wolcott-Rallison syndrome. , 1997, Pediatric pathology & laboratory medicine : journal of the Society for Pediatric Pathology, affiliated with the International Paediatric Pathology Association.

[24]  A. Aguzzi,et al.  Deficient signaling in mice devoid of double‐stranded RNA‐dependent protein kinase. , 1995, The EMBO journal.

[25]  N. Shiojiri.  [Molecular mechanisms of liver development]. , 2002, Seikagaku. The Journal of Japanese Biochemical Society.

[26]  P. Walter,et al.  The unfolded protein response : an intracellular signalling pathway with many surprising features , 1998 .

[27]  F. Urano,et al.  Coupling of stress in the ER to activation of JNK protein kinases by transmembrane protein kinase IRE1. , 2000, Science.

[28]  R. Kaufman,et al.  The unfolded protein response represses nitrogen-starvation induced developmental differentiation in yeast. , 2000, Genes & Development.

[29]  R. Kaufman,et al.  Double-stranded RNA-activated protein kinase mediates virus-induced apoptosis: a new role for an old actor. , 1999, Proceedings of the National Academy of Sciences of the United States of America.

[30]  H. Okamoto,et al.  Translational control of proinsulin synthesis by glucose , 1980, Nature.

[31]  V. M. Pain.  Initiation of protein synthesis in eukaryotic cells. , 1996, European journal of biochemistry.

[32]  S. Bonner-Weir,et al.  Chronic Hyperglycemia Triggers Loss of Pancreatic β Cell Differentiation in an Animal Model of Diabetes* , 1999, The Journal of Biological Chemistry.

[33]  A. Dorner,et al.  Increased synthesis of secreted proteins induces expression of glucose-regulated proteins in butyrate-treated Chinese hamster ovary cells. , 1989, The Journal of biological chemistry.

[34]  A. Hinnebusch,et al.  7 Translational Control of GCN4: Gene-specific Regulation by Phosphorylation of elF2 , 1996 .

[35]  F. Urano,et al.  IRE1 and efferent signaling from the endoplasmic reticulum. , 2000, Journal of cell science.

[36]  G. Sandusky,et al.  Characterization of a Mutant Pancreatic eIF-2α Kinase, PEK, and Co-localization with Somatostatin in Islet Delta Cells* , 1999, The Journal of Biological Chemistry.

[37]  U. Schibler,et al.  CCAAT/enhancer-binding protein mRNA is translated into multiple proteins with different transcription activation potentials. , 1993, Proceedings of the National Academy of Sciences of the United States of America.

[38]  M. Brostrom,et al.  Phosphorylation of eukaryotic initiation factor (eIF) 2 alpha and inhibition of eIF-2B in GH3 pituitary cells by perturbants of early protein processing that induce GRP78. , 1992, The Journal of biological chemistry.

[39]  D. Ron,et al.  Diabetes mellitus and exocrine pancreatic dysfunction in perk-/- mice reveals a role for translational control in secretory cell survival. , 2001, Molecular cell.

[40]  R. Kaufman,et al.  The endoribonuclease activity of mammalian IRE1 autoregulates its mRNA and is required for the unfolded protein response. , 2000, Genes & development.

[41]  R. Sood,et al.  Translational Control -subunit Kinase, Pek, Involved in Α Pancreatic Eukaryotic Initiation Factor 2 Identification and Characterization Of , 1998 .

[42]  K. Mori.  Tripartite Management of Unfolded Proteins in the Endoplasmic Reticulum , 2000, Cell.

[43]  Peter Walter,et al.  Functional and Genomic Analyses Reveal an Essential Coordination between the Unfolded Protein Response and ER-Associated Degradation , 2000, Cell.

[44]  C. Barlow,et al.  Increased Hepatic Cell Proliferation and Lung Abnormalities in Mice Deficient in CCAAT/Enhancer Binding Protein α* , 1996, The Journal of Biological Chemistry.

[45]  K. Mori,et al.  Mammalian transcription factor ATF6 is synthesized as a transmembrane protein and activated by proteolysis in response to endoplasmic reticulum stress. , 1999, Molecular biology of the cell.

[46]  D. Ron,et al.  Perk is essential for translational regulation and cell survival during the unfolded protein response. , 2000, Molecular cell.

[47]  A. Bradley,et al.  Impaired energy homeostasis in C/EBP alpha knockout mice , 1995, Science.

[48]  I. Pastan,et al.  Induction of two transformation-sensitive membrane polypeptides in normal fibroblasts by a block in glycoprotein synthesis or glucose deprivation , 1977, Cell.

[49]  R. Kaufman,et al.  Phosphorylation of Eukaryotic Translation Initiation Factor 2 Mediates Apoptosis in Response to Activation of the Double-stranded RNA-dependent Protein Kinase* , 1998, The Journal of Biological Chemistry.

[50]  S. Akira,et al.  Targeted disruption of ATF4 discloses its essential role in the formation of eye lens fibres , 1998, Genes to cells : devoted to molecular & cellular mechanisms.