Alternative titles; symbols
HGNC Approved Gene Symbol: STK39
Cytogenetic location: 2q24.3 Genomic coordinates (GRCh38) : 2:167,954,022-168,247,595 (from NCBI)
By database analysis, Johnston et al. (2000) identified a kinase domain fragment of STK39, which they called SPAK, based on its homology with the STE20 (STK25; 602255) family of kinases. They used this fragment to clone full-length STK39 from a brain cDNA library. The deduced 547-amino acid protein has a calculated molecular mass of 59.6 kD. STK39 contains an N-terminal series of proline and alanine repeats (PAPA box), followed by a serine/threonine kinase catalytic domain, a nuclear localization signal, a consensus caspase cleavage recognition motif, and a C-terminal region. Northern blot analysis detected ubiquitous expression of a 3.8-kb transcript, with most abundant expression in brain and pancreas. Western blot analysis of mouse tissues detected a protein of about 60 kD in all tissues examined.
Johnston et al. (2000) characterized human and murine STK39 and confirmed that the recombinant protein is a serine/threonine kinase that can phosphorylate itself and an exogenous substrate in vitro. STK39 immunoprecipitated from transfected mammalian cells in a complex with another serine/threonine kinase that phosphorylated catalytically inactive STK39. STK39 activated the p38 MAP kinase (600289) pathway in cotransfection assays. Full-length STK39 was expressed in the cytoplasm in transfected cells, while a mutant corresponding to caspase-cleaved STK39 localized predominantly in the nucleus.
The International Radiation Hybrid Mapping Consortium mapped the STK39 gene to chromosome 2 (stSG52257).
Johnston, A. M., Naselli, G., Gonez, L. J., Martin, R. M., Harrison, L. C., DeAizpurua, H. J. SPAK, a STE20/SPS1-related kinase that activates the p38 pathway. Oncogene 19: 4290-4297, 2000. [PubMed: 10980603] [Full Text: https://doi.org/10.1038/sj.onc.1203784]