Catalytic domain of the Serine/Threonine kinases, Receptor Interacting Protein 4 and similar proteins
STKs catalyze the transfer of the gamma-phosphoryl group from ATP to serine/threonine residues on protein substrates. This subfamily is composed of RIP4, ankyrin (ANK) repeat and kinase domain containing 1 (ANKK1), and similar proteins, all of which harbor C-terminal ANK repeats. RIP4, also called Protein Kinase C-associated kinase (PKK), regulates keratinocyte differentiation and cutaneous inflammation. It activates NF-kappaB and is important in the survival of diffuse large B-cell lymphoma cells. The ANKK1 protein, also called PKK2, has not been studied extensively. The ANKK1 gene, located less than 10kb downstream of the D2 dopamine receptor (DRD2) locus, is altered in the Taq1 A1 polymorphism, which is related to a reduced DRD2 binding affinity and consequently, to mental disorders. The RIP4-like subfamily is part of a larger superfamily that includes the catalytic domains of other protein STKs, protein tyrosine kinases, RIO kinases, aminoglycoside phosphotransferase, choline kinase, and phosphoinositide 3-kinase.