ABSTRACT
Vitamin D3 upregulated protein-1 (VDUP1), which is identical to TRX binding protein-2 (TBP-2) and thioredoxin interacting protein (TXNIP), was originally identied as a vitamin D-induced protein in HL-60 cells treated with 1,25-dihydroxyvitamin D (Chen and DeLuca 1994). Later, it was identied to bind to the reduced thioredoxin (Trx) by yeast two-hybrid screening and to inhibit the antioxidant function of Trx (Junn et al. 2000; Nishiyama et al. 1999). VDUP1 recognizes the catalytic active center of Trx via cysteine 247 residues. By binding the active center of Trx, VDUP1 can inhibit the reducing activity of Trx (Junn et al. 2000). VDUP1 has 2 beta-arrestin domains and 11 cysteine residues. This implies VDUP1 can bind many other proteins and interactions may be inuenced by intracellular redox status. VDUP1 can interact with NLRP3 in a redox-dependent manner (Zhou et al. 2010). For binding with Trx, two cysteine residues, i.e., Cys 247 and Cys 63, are important, and mutation in these cysteines results in a failure of the binding of VDUP1 and Trx.
