This entry represents the Rdx family of selenoproteins, which includes mammalian selenoproteins SelW, SelV, SelT and SelH, bacterial SelW-like proteins and cysteine-containing proteins of unknown function in all three domains of life. Mammalian Rdx12 and its fish selenoprotein orthologues are also members of this family []. These proteins possess a thioredoxin-like fold and a conserved CXXC or CxxU (U is selenocysteine) motif near the N terminus, suggesting a redox function. Rdx proteins can use catalytic cysteine (or selenocysteine) to form transient mixed disulphides with substrate proteins. Selenium (Se) plays an essential role in cell survival and most of the effects of Se are probably mediated by selenoproteins. Selenoprotein W (SelW) plays an important role in protection of neurons from oxidative stress during neuronal development [], []. Selenoprotein T (SelT) is conserved from plants to humans. SelT is localized to the endoplasmic reticulum through a hydrophobic domain. The protein binds to UDP-glucose:glycoprotein glucosyltransferase (UGTR), the endoplasmic reticulum (ER)-resident protein, which is known to be involved in the quality control of protein folding [, ]. The function of SelT is unknown, although it may have a role in PACAP signaling during PC12 cell differentiation [, ]. Selenoprotein H (SelH) protects neurons against UVB-induced damage by inhibiting apoptotic cell death pathways, by preventing mitochondrial depolarization, and by promoting cell survival pathways [].
