title: ERp57 modulates STAT3 signaling from the lumen of the endoplasmic reticulum.
abstract: ERp57 is an endoplasmic reticulum (ER) resident thiol disulfide oxidoreductase. Using the gene trap technique, we created a ERp57-deficient mouse model. Targeted deletion of the Pdia3 gene, which encodes ERp57, in mice is embryonic lethal at embryonic day (E) 13.5. Beta-galactosidase reporter gene analysis revealed that ERp57 is expressed early on during blastocyst formation with the highest expression in the inner cell mass. In early stages of mouse embryonic development (E11.5) there is a relatively low level of expression of ERp57. As the embryos developed, ERp57 became highly expressed in both the brain and the lungs (E15.5 and E18.5). The absence of ERp57 has no impact on ER morphology; expression of ER-associated chaperones and folding enzymes, ER stress, or apoptosis. ERp57 has been reported to interact with STAT3 (signal transducer and activator of transcription)-DNA complexes. We show here that STAT3-dependent signaling is increased in the absence of ERp57 and this can be rescued by expression of ER-targeted ERp57 but not by cytoplasmic-targeted protein, indicating that ERp57 affects STAT3 signaling from the lumen of the ER. ERp57 effects on STAT3 signaling are enhanced by ER luminal complex formation between ERp57 and calreticulin. In conclusion, we show that ERp57 deficiency in mouse is embryonic lethal at E13.5 and ERp57-dependent modulation of STAT3 signaling may contribute to this phenotype.
authors.affiliation: Department of Biochemistry, School of Molecular and Systems Medicine, University of Alberta, Edmonton, Alberta T6G 2H7, Canada.
authors.forename: Helen
authors.initials: H
authors.lastname: Coe
authors.forename: Joanna
authors.initials: J
authors.lastname: Jung
authors.forename: Jody
authors.initials: J
authors.lastname: Groenendyk
authors.forename: Daniel
authors.initials: D
authors.lastname: Prins
authors.forename: Marek
authors.initials: M
authors.lastname: Michalak
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000378:metabolism; D001921:Brain / Q000196:embryology / Q000378:metabolism; D004622:Embryo, Mammalian; D004721:Endoplasmic Reticulum / Q000502:physiology* / Q000648:ultrastructure; D018507:Gene Expression Regulation, Developmental; D008168:Lung / Q000196:embryology / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D019704:Protein Disulfide-Isomerases / Q000235:genetics / Q000502:physiology*; D050796:STAT3 Transcription Factor / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: D050796:STAT3 Transcription Factor; C494087:Stat3 protein, mouse; C513195:Pdia3 protein, mouse; D019704:Protein Disulfide-Isomerases