UMP-CMP kinase 2 (CMPK2) is the first nucleoside monophosphate kinase that has been identified in human mitochondria. It is a component of the salvage pathway for nucleotide synthesis that may participate in terminal differentiation of monocytic cells. There are two distinct domains of CMPK2: the N-terminal domain with unknown function and the C-terminal domain with the kinase function, suggesting that CMPK2 may be a bifunctional protein with other biological functions in addition to its UMP-CMP kinase activity. CMPK2 may participate in dUTP and dCTP synthesis and is responsible for phosphorylation of dCMP and dUMP in mitochondria. CMPK2 is actively involved in macrophage activation and the inflammatory responseSynonyms: LOC129607, UMP-CMP kinase 2