This protein is considered an atypical serine/threonine kinase, because it lacks the conventional structural elements necessary for the substrate recognition as well as a lysine residue that in all other serine/threonine kinases participates in the catalytic event. TP53RK has protein kinase activity in vitro, but in the context of the EKC/KEOPS complex, the catalytic subunit OSGEP switches the activity of TP53RK from kinase into ATPase (By similarity)
