Serine/Threonine Kinase 17A (STK17A)

The full-length STK17A cDNA encodes a deduced 414-amino acid protein with a molecular mass of 46.56 kD. The putative kinase domain is located at the N terminus and contains all 11 subdomains conserved among ser/thr kinases. STK17A and STK17B share 59.7% amino acid identity. Northern blot analysis revealed that STK17A is expressed as a 1.9-kb transcript predominantly in placenta, but also in heart, lung, skeletal muscle, kidney, and pancreas. An in vitro assay demonstrated that STK17A is capable of autophosphorylation and of phosphorylating myosin light chain as an exogenous substrate, and that the noncatalytic C terminus is crucial for full kinase activity. Immunofluorescence studies showed that both STK17A and STK17B are localized in the nucleus. STK17A and STK17B share similar levels of apoptosis-inducing activity.