Protein Domain : TryX and NRX, thioredoxin domain IPR045870

Type	Domain
Description	This entry represents the thioredoxin domain found in tryparedoxin (TryX) from trypanosomes and nucleoredoxin (NRX) from animals and plants. They belong to the Thioredoxin (TRX) family, whose members are evolutionary conserved proteins involved in various biologic processes by regulating the response to oxidative stress [ ]. TryX and NRX are disulfide oxidoreductases that alter the redox state of target proteins via the reversible oxidation of an active centre CXXC motif [, ].TryX is involved in the regulation of oxidative stress in parasitic trypanosomatids by reducing TryX peroxidase, which in turn catalyses the reduction of hydrogen peroxide and organic hydroperoxides. TryX derives reducing equivalents from reduced trypanothione, a polyamine peptide conjugate unique to trypanosomatids, which is regenerated by the NADPH-dependent flavoprotein trypanothione reductase [ , , ]. Vertebrate NRX is a 400-amino acid nuclear protein with one redox active TRX domain containing a CPPC active site motif followed by one redox inactive TRX-like domain. Mouse NRX transcripts are expressed in all adult tissues but is restricted to the nervous system and limb buds in embryos [ , , ]. It has been shown to interacts with Dishevelled (Dvl), an essential adaptor protein for Wnt signalling, and blocks the activation of the Wnt pathway []. Plant NRX, longer than the vertebrate NRX by about 100-200 amino acids, is a nuclear protein containing a redox inactive TRX-like domain between two redox active TRX domains. Both vertebrate and plant NRXs show thiol oxidoreductase activity in vitro. Their localization in the nucleus suggests a role in the redox regulation of nuclear proteins such as transcription factors [, ].
Short Name	TryX_NRX_thioredoxin_dom