The phosphorylation and dephosphorylation of proteins on serine and threonine residues is an essential means of regulating a broad range of cellular functions in eukaryotes, including cell division, homeostasis and apoptosis. A group of proteins that are intimately involved in this process are the serine/threonine (Ser/Thr) protein kinases. ANKK1 (ankyrin repeat and kinase domain containing 1), also known as PKK2 or SGK288, is a 765 amino acid protein that belongs to the Ser/Thr protein kinase family and contains 12 ANK repeats and one protein kinase domain. Highly expressed in brain tissue and present in lower amounts in placenta and spinal cord, ANKK1 functions to catalyze the ATP-dependent phosphorylation of target proteins and is thought to play a role in alcohol and nicotine dependence. The gene encoding ANKK1 maps to human chromosome 11, which houses over 1,400 genes and comprises nearly 4% of the human genome.