title: The conserved Trp114 residue of thioredoxin reductase 1 has a redox sensor-like function triggering oligomerization and crosslinking upon oxidative stress related to cell death.
abstract: The selenoprotein thioredoxin reductase 1 (TrxR1) has several key roles in cellular redox systems and reductive pathways. Here we discovered that an evolutionarily conserved and surface-exposed tryptophan residue of the enzyme (Trp114) is excessively reactive to oxidation and exerts regulatory functions. The results indicate that it serves as an electron relay communicating with the FAD moiety of the enzyme, and, when oxidized, it facilitates oligomerization of TrxR1 into tetramers and higher multimers of dimers. A covalent link can also be formed between two oxidized Trp114 residues of two subunits from two separate TrxR1 dimers, as found both in cell extracts and in a crystal structure of tetrameric TrxR1. Formation of covalently linked TrxR1 subunits became exaggerated in cells on treatment with the pro-oxidant p53-reactivating anticancer compound RITA, in direct correlation with triggering of a cell death that could be prevented by antioxidant treatment. These results collectively suggest that Trp114 of TrxR1 serves a function reminiscent of an irreversible sensor for excessive oxidation, thereby presenting a previously unrecognized level of regulation of TrxR1 function in relation to cellular redox state and cell death induction.
authors.affiliation: Division of Biochemistry, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-17177 Stockholm, Sweden.
authors.forename: J
authors.initials: J
authors.lastname: Xu
authors.affiliation: Division of Biochemistry, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-17177 Stockholm, Sweden.
authors.forename: S E
authors.initials: SE
authors.lastname: Eriksson
authors.affiliation: Division of Biochemistry, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-17177 Stockholm, Sweden.
authors.forename: M
authors.initials: M
authors.lastname: Cebula
authors.affiliation: Division of Molecular Structural Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-17177 Stockholm, Sweden.
authors.forename: T
authors.initials: T
authors.lastname: Sandalova
authors.affiliation: Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, SE-17177 Stockholm, Sweden.
authors.forename: E
authors.initials: E
authors.lastname: Hedström
authors.affiliation: Division of Biochemistry, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-17177 Stockholm, Sweden.
authors.forename: I
authors.initials: I
authors.lastname: Pader
authors.affiliation: Division of Biochemistry, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-17177 Stockholm, Sweden.
authors.forename: Q
authors.initials: Q
authors.lastname: Cheng
authors.affiliation: Department of Pharmacology and Toxicology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA.
authors.forename: C R
authors.initials: CR
authors.lastname: Myers
authors.affiliation: Department of Biophysics, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA.
authors.forename: W E
authors.initials: WE
authors.lastname: Antholine
authors.affiliation: Department of Molecular Immunology and Toxicology, National Institute of Oncology, Rath György ut 7-91, 1122, Budapest, Hungary.
authors.forename: P
authors.initials: P
authors.lastname: Nagy
authors.affiliation: Ludwig Institutet for Cancer Research Ltd., Uppsala University BMC, SE-75 124 Uppsala, Sweden.
authors.forename: U
authors.initials: U
authors.lastname: Hellman
authors.affiliation: Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, SE-17177 Stockholm, Sweden.
authors.forename: G
authors.initials: G
authors.lastname: Selivanova
authors.affiliation: Division of Molecular Structural Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-17177 Stockholm, Sweden.
authors.forename: Y
authors.initials: Y
authors.lastname: Lindqvist
authors.affiliation: Division of Biochemistry, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-17177 Stockholm, Sweden.
authors.forename: E S J
authors.initials: ES
authors.lastname: Arnér
mesh_terms: D000818:Animals; D016923:Cell Death / Q000187:drug effects; D045744:Cell Line, Tumor; D017124:Conserved Sequence; D003432:Cross-Linking Reagents / Q000494:pharmacology*; D005182:Flavin-Adenine Dinucleotide / Q000378:metabolism; D005663:Furans / Q000494:pharmacology; D045325:HCT116 Cells; D006801:Humans; D007700:Kinetics; D009637:Masoprocol / Q000494:pharmacology; D008958:Models, Molecular; D050505:Mutant Proteins / Q000378:metabolism; D010084:Oxidation-Reduction / Q000187:drug effects; D018384:Oxidative Stress / Q000187:drug effects*; D055503:Protein Multimerization / Q000187:drug effects*; D051381:Rats; D013329:Structure-Activity Relationship; D054481:Thioredoxin Reductase 1 / Q000378:metabolism*; D014364:Tryptophan / Q000378:metabolism*
chemical_list: D003432:Cross-Linking Reagents; D005663:Furans; D050505:Mutant Proteins; C118989:NSC 652287; D005182:Flavin-Adenine Dinucleotide; D009637:Masoprocol; D014364:Tryptophan; D054481:Thioredoxin Reductase 1