Knocking down selenoprotein T (SelT) alters cell adhesion and elevates selenoprotein W (SelW) expression in murine fibroblast cells.

Abstract

Selenium, a crucial dietary trace element is associated with numerous metabolic pathways and unlike most trace elements which function as cofactors of proteins; it is incorporated into proteins as the amino acid selenocysteine (Sec). Proteins having Sec residue are termed selenoproteins. Among the 24 selenoproteins reported in rodents, only half have been functionally characterized, with most being involved in redox reactions. One selenoprotein, whose exact biological function is not yet known, is selenoprotein T (SelT). SelT possesses a CxxU motif and a thioredoxin like fold, owing to which it has recently been assigned to a new protein family Rdx, which is a thioredoxin‐like family. Intracellular localization studies in murine cell lines localize SelT to Golgi and endoplasmic reticulum. In an attempt to determine the biological function of SelT, in the present study, we knockdown the expression of SelT in mouse fibroblast cells (NIH3T3) and examined its effect on these cells. Results indicate that knocking down SelT alters cell adhesion and enhances the expression of some stress responsive genes. Interestingly, loss of SelT elevates expression of selenoprotein W (SelW), another member of the Rdx family, which might functionally compensate for SelT. This research was supported by the Intramural Research Program of the NIH, NCI, CCR and by NIH grants to VNG.