Selenophosphate Synthetase 2 (SEPHS2)

SEPHS2 encodes an enzyme that synthesizes selenophosphate from selenide and ATP. This protein itself contains a selenocysteine residue in its predicted active site. The 3' UTR of the gene has a stem-loop secondary structure called a selenocysteine insertion sequence (SECIS) element, which allows UGA to direct the incorporation of selenocysteine rather than signal a translational stop. Alternatively spliced transcripts have been identified, but their biological validity has not been determined. The deduced 448-amino acid SPS2 protein contains Walker A- and B-like motifs, which are characteristic of alpha/beta nucleotide-binding folds. The SPS2 Walker A-like motif is a gly-rich site that includes the sec residue. Levels of Sps2 mRNA were upregulated upon activation of CD4-positive lymphocytes.