Thiordoxin regulates the DNA binding activity of NF-χB by reduction of a disulphid bond involving cysteine 62

Abstract

A role for redox regulation in activation of the NF-kappa B transcription factor was suggested by the observation that DNA binding activity of free protein, but not preformed DNA-protein complex, is inhibited by -SH modifying agents but enhanced by reducing agents. Mutagenesis of conserved cysteine residues in the p50 subunit identified amino acid 62 as being important for DNA binding, as a serine substitution at this position reduces DNA binding affinity, but renders the protein insensitive to -SH modifying agents. DNA binding activity of the wild type protein but not the amino acid 62 mutant was also stimulated by thioredoxin while detection of disulphide cross linked dimers in p50 but not the amino acid 62 mutant suggests that thioredoxin stimulates DNA binding by reduction of a disulphide bond involving cysteine 62. The physiological relevance of these findings was supported by the observation that cotransfection of a plasmid expressing human thioredoxin and an HIV LTR driven reporter construct resulted in an NF-kappa B dependent increase in expression of the reporter gene. Thus modification of p50 by thioredoxin, a gene induced by stimulation of T-lymphocytes in parallel with NF-kappa B translocation, is a likely step in the cascade of events leading to full NF-kappa B activation.

Delayed radioprotection by nuclear transcription factor κB -mediated induction of manganese superoxide dismutase in human microvascular endothelial cells after exposure to the free radical scavenger WR1065

“…This finding is in agreement with the observations of others who demonstrated a similar specificity in NFκB activation in both normal and malignant cells following exposure to thiol-containing drugs such as N-acetyl-L-cysteine, dithiothreitol, 2-mercaptoethanol, WR1065, and oltipraz [14,16,18]. This is not surprising since NFκB is a well-characterized redox-sensitive transcription factor whose activation is known to be induced by both oxidative stress [14][15][16][17][18] and reducing agents that are capable of altering the redox state of the cysteine 62 residue of its p50 subunit [35]. Correlating with NFκB activation is the robust expression of the MnSOD gene.…”

The Requirement of Reversible Cysteine Sulfenic Acid Formation for T Cell Activation and Function

“…Abate et al (24) demonstrated that the DNA binding activity of c-Fos and c-Jun is sensitive to reversible cysteine oxidation at amino acids 154 and 252, respectively. NF-B is also subject to redox regulation on cysteine 62 on the p50 subunit (49). The DNA binding activity of the transcription factor is inhibited by oxidation (23).…”

Disulfide Bond-mediated Multimerization of Ask1 and Its Reduction by Thioredoxin-1 Regulate H2O2-induced c-Jun NH2-terminal Kinase Activation and Apoptosis

“…Likewise, an important component of mammalian cell responses to oxidative stress involves the oxidation of active cysteines in many types of proteins, thereby regulating several activities. Some transcription factors, such as activator protein-1 and nuclear factor-B (NF-B) bear oxidation-sensitive cysteines and they are regulated through oxidation during oxidative stress (Abate et al, 1990;Toledano and Leonard, 1991;Matthews et al, 1992). The formation of intramolecular disulfides in the catalytic core of many phosphatases, including protein tyrosine phosphatase and lipid phosphatases such as phosphatase with sequence homology to tensin (PTEN), results in their reversible inhibition (Lee et al, 2002;Rhee et al, 2005;Salmeen and Barford, 2005;Stone and Yang, 2006).…”

“…Thioredoxin also contributes to H 2 O 2 scavenging by recycling oxidized peroxiredoxins, an important thiol-based peroxidase family enzyme (Rhee et al, 2005). Thioredoxin as a thiol reductase has also regulatory functions, capable of reducing, either directly or indirectly, several redox-sensitive transcriptional factors (Matthews et al, 1992;Hirota et al, 1997Hirota et al, , 1999Ueno et al, 1999).…”