MAPK15 is a 544 amino acid protein that belongs to the CMGC Ser/Thr protein kinase family (MAP kinase subfamily). MAP kinases play a significant role in many biological processes, including cell adhesion and spreading, cell differentiation and apoptosis. MAPK15 functions as a catalytic kinase using ATP to produce ADP and a phosphoprotein. A TXY motif, containing one threonine and one tyrosine residue, activates the MAP kinases upon phosphorylation. MAPK15 is a ubiquitously expressed protein with highest expression found in lung and kidney.