title: Lafora disease fibroblasts exemplify the molecular interdependence between thioredoxin 1 and the proteasome in mammalian cells.
abstract: Thioredoxin 1 (Trx1) is a key regulator of cellular redox balance and participates in cellular signaling events. Recent evidence from yeast indicates that members of the Trx family interact with the 20S proteasome, indicating redox regulation of proteasome activity. However, there is little information about the interrelationship of Trx proteins with the proteasome system in mammalian cells, especially in the nucleus. Here, we have investigated this relationship under various cellular conditions in mammalian cells. We show that Trx1 levels and its subcellular localization (cytosol, endoplasmic reticulum, and nucleus) depend on proteasome activity during the cell cycle in NIH3T3 fibroblasts and under stress conditions, when proteasomes are inhibited. In addition, we also studied in these cells how the main cellular antioxidant systems are stimulated when proteasome activity is inhibited. Finally, we describe a reduction in Trx1 levels in Lafora disease fibroblasts and demonstrate that the nuclear colocalization of Trx1 with 20S proteasomes in laforin-deficient cells is altered compared with control cells. Our results indicate a close relationship between Trx1 and the 20S nuclear proteasome and give a new perspective to the study of diseases or physiopathological conditions in which defects in the proteasome system are associated with oxidative stress.
authors.affiliation: Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Valencia, Spain; Fundación del Hospital Clínico Universitat de Valencia-INCLIVA, Valencia, Spain; Department of Physiology, University of Valencia, 46010 Valencia, Spain.
authors.forename: José Luis
authors.initials: JL
authors.lastname: García-Giménez
authors.affiliation: Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Valencia, Spain.
authors.forename: Marta
authors.initials: M
authors.lastname: Seco-Cervera
authors.affiliation: Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Valencia, Spain; Centro de Investigación Príncipe Felipe, Valencia, Spain.
authors.forename: Carmen
authors.initials: C
authors.lastname: Aguado
authors.affiliation: Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Valencia, Spain; Instituto de Biomedicina de Valencia, Consejo Superior de Investigaciones Científicas, Valencia, Spain.
authors.forename: Carlos
authors.initials: C
authors.lastname: Romá-Mateo
authors.affiliation: Fundación del Hospital Clínico Universitat de Valencia-INCLIVA, Valencia, Spain; Department of Physiology, University of Valencia, 46010 Valencia, Spain.
authors.forename: Francisco
authors.initials: F
authors.lastname: Dasí
authors.affiliation: Research Core Facility, Medical School, University of Valencia, 46010 Valencia, Spain.
authors.forename: Sonia
authors.initials: S
authors.lastname: Priego
authors.affiliation: Research Core Facility, Medical School, University of Valencia, 46010 Valencia, Spain.
authors.forename: Jelena
authors.initials: J
authors.lastname: Markovic
authors.affiliation: Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Valencia, Spain; Centro de Investigación Príncipe Felipe, Valencia, Spain.
authors.forename: Erwin
authors.initials: E
authors.lastname: Knecht
authors.affiliation: Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Valencia, Spain; Instituto de Biomedicina de Valencia, Consejo Superior de Investigaciones Científicas, Valencia, Spain.
authors.forename: Pascual
authors.initials: P
authors.lastname: Sanz
authors.affiliation: Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Valencia, Spain; Fundación del Hospital Clínico Universitat de Valencia-INCLIVA, Valencia, Spain; Department of Physiology, University of Valencia, 46010 Valencia, Spain. Electronic address: Federico.V.Pallardo@uv.es.
authors.forename: Federico V
authors.initials: FV
authors.lastname: Pallardó
mesh_terms: D000818:Animals; D015153:Blotting, Western; D000091342:Endoplasmic Reticulum Chaperone BiP; D005347:Fibroblasts / Q000378:metabolism*; D005434:Flow Cytometry; D006801:Humans; D047468:Immunoprecipitation; D020192:Lafora Disease / Q000378:metabolism*; D051379:Mice; D018613:Microscopy, Confocal; D041681:NIH 3T3 Cells; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000502:physiology*; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013879:Thioredoxins / Q000378:metabolism*
chemical_list: D000091342:Endoplasmic Reticulum Chaperone BiP; C000717247:HSPA5 protein, human; C000717248:Hspa5 protein, mouse; D013879:Thioredoxins; D046988:Proteasome Endopeptidase Complex
keywords: 78-kDa glucose-regulated protein; ATF4; Antioxidant enzymes; BIP/Grp78; BrdU; C/EBP-homologous protein (DNA damage-inducible transcript 3 protein); CHOP; Cell proliferation; CuZnSOD; DSB; ER; Free radicals; GSH; GSSG; Lafora disease; MnSOD; PARP; PDI; Proteasome; Rare diseases; Thioredoxin 1; Trx1; TrxR1; UPR; bromodeoxyuridine; copper–zinc superoxide dismutase; cyclic AMP-dependent transcription factor 4; double-strand break; endoplasmic reticulum; manganese superoxide dismutase; oxidized glutathione; poly(ADP-ribose) polymerase; protein disulfide isomerase; reduced glutathione; thioredoxin 1; thioredoxin reductase 1; unfolded protein response