Catalytic activity: ATP + a protein = ADP + a phosphoprotein. Cofactor: Magnesium. function: Seems to act exclusively upon threonine residues. similarity: Belongs to the protein kinase superfamily. similarity: Belongs to the protein kinase superfamily. NEK Ser/Thr protein kinase family. NIMA subfamily. similarity: Contains 1 protein kinase domain. tissue specificity: Highest expression in adult heart, followed by pancreas, skeletal muscle, brain, liver, kidney, lung and placenta. Present in most primary carcinomas.