Selenophosphate synthetase 2 (SEPHS2)

Selenophosphate synthetase 2 is an enzyme critical for cellular selenium utilization and selenoprotein biosynthesis[1][2][3]. It catalyzes the ATP-dependent formation of monoselenophosphate from selenide, which serves as the selenium donor required for the cotranslational incorporation of selenocysteine—the 21st amino acid—into proteins at UGA codons[1][2][3]. SEPHS2 itself contains selenocysteine at its active site and may be subject to autoregulatory control. It functions in concert with other proteins involved in the selenocysteine biosynthesis pathway, such as SEPSECS and SECp43[1]. Expression and amplification of SEPHS2 are notably increased in certain cancers, especially triple-negative breast cancer, where it is being evaluated as a prognostic marker and potential therapeutic target[3]. Deficiency or dysregulation of SEPHS2 is linked to rare diseases such as Keshan disease and congenital myopathy[2]. No approved drugs directly target SEPHS2, and its biological context suggests that therapeutic modulation poses significant safety and specificity challenges[1][2][3].

Other names

SPS2SPS2BSelenide, water dikinase 2Selenium donor protein 2Selenophosphate synthase 2selenoprotein SEPHS2

Not specifically described; as an enzyme, theoretical mechanism would involve inhibition or modulation of selenophosphate synthesis, affecting selenoprotein assembly