Work

Thioredoxin 1 Is Inactivated Due to Oxidation Induced by Peroxiredoxin under Oxidative Stress and Reactivated by the Glutaredoxin System

Year: 2013

Type: article

Abstract: The mammalian cytosolic thioredoxin system, comprising thioredoxin (Trx), Trx reductase, and NADPH, is the major protein-disulfide reductase of the cell and has numerous functions. Besides the active site thiols, human Trx1 contains three non-active site cysteine residues at positions 62, 69, and 73. A two-disulfide form of Trx1, containing an active site disulfide between Cys-32 and Cys-35 and a non-active site disulfide between Cys-62 and Cys-69, is inactive either as a disulfide reductase or as a substrate for Trx reductase. This could possibly provide a structural switch affecting Trx1 function during oxidative stress and redox signaling. We found that two-disulfide Trx1 was generated in A549 cells under oxidative stress. In vitro data showed that two-disulfide Trx1 was generated from oxidation of Trx1 catalyzed by peroxiredoxin 1 in the presence of H 2 O 2 . The redox Western blot data indicated that the glutaredoxin system protected Trx1 in HeLa cells from oxidation caused by ebselen, a superfast oxidant for Trx1. Our results also showed that physiological concentrations of glutathione, NADPH, and glutathione reductase reduced the non-active site disulfide in vitro . This reaction was stimulated by glutaredoxin 1 via the so-called monothiol mechanism. In conclusion, reversible oxidation of the non-active site disulfide of Trx1 is suggested to play an important role in redox regulation and cell signaling via temporal inhibition of its protein-disulfide reductase activity for the transmission of oxidative signals under oxidative stress. Background: The Cys-62/Cys-69 dithiol of Trx1 is predicted to have a profound effect on cell signaling. Results: The Cys-62/Cys-69 dithiol of Trx1 was oxidized by Prx1, and this disulfide was reduced by the GSH/glutaredoxin system. Conclusion: Trx1 is involved in redox regulation via reversible oxidation of the Cys-62/Cys-69 dithiol of Trx1. Significance: We demonstrated the critical role of Trx1 oxidation in cell signaling.

Source: Journal of Biological Chemistry

DOI: 10.1074/jbc.m113.495150

Authors: Yatao Du, Huihui Zhang, Xu Zhang, Jun Lu, Arne Holmgren

Institution: Karolinska Institutet

Language: English

Topic: Redox biology and oxidative stress

Subfield: Molecular Biology

Field: Biochemistry, Genetics and Molecular Biology

Domain: Life Sciences

SDG: Good health and well-being

Open Access status: hybrid

Estimated APC paid: $3,430