Alternative titles; symbols
HGNC Approved Gene Symbol: PSTK
Cytogenetic location: 10q26.13 Genomic coordinates (GRCh38) : 10:122,980,401-122,990,390 (from NCBI)
In eukaryotes, decoding of the UGA codon as selenocysteine (Sec) requires a Sec insertion sequence (SECIS) in the 3-prime untranslated region of the mRNA. A specific elongation factor, EFSEC (607695), specifically recognizes selenocysteyl-tRNA(Ser)Sec and the SECIS and directs insertion of Sec into protein. Carlson et al. (2004) performed a computational search of archaeal and eukaryotic genomes to find kinase-like genes that occurred in organisms with the Sec insertion machinery but not in organisms lacking this machinery. They found 27 ORFs that were further screened for homology to known kinase domains and proteins in the National Center for Biotechnology Information nonredundant database. They identified a novel protein, designated PSTK, that had homologs in eukaryotes with a functional Sec insertion system, but not in those lacking this system. The PSTK cDNA was isolated and cloned into a His-tag expression vector. The deduced human PSTK protein contains 359 amino acids with a predicted ATP-binding domain. It shares 80% sequence identity with the mouse homolog.
Carlson et al. (2004) demonstrated that PSTK specifically catalyzed the formation of phosphoseryl-tRNA(Ser)Sec from seryl-tRNA(Ser)Sec and ATP in the presence of Mg2+. In binding assays, both tRNA(Ser)Sec and seryl-tRNA(Ser)Sec bound to PSTK, but ATP enhanced the binding of tRNA(Ser)Sec and decreased the binding of seryl-tRNA(Ser)Sec. Carlson et al. (2004) suggested that PSTK plays an important role in selenoprotein biosynthesis and/or regulation.
The International Radiation Hybrid Mapping Consortium mapped the PSTK gene to chromosome 10 (RH94240).
Carlson, B. A., Xu, X.-M., Kryukov, G. V., Rao, M., Berry, M. J., Gladyshev, V. N., Hatfield, D. L. Identification and characterization of phosphoseryl-tRNA(Ser)Sec kinase. Proc. Nat. Acad. Sci. 101: 12848-12853, 2004. [PubMed: 15317934] [Full Text: https://doi.org/10.1073/pnas.0402636101]