NME2(NME/NM23 nucleoside diphosphate kinase 2) also called non-metastatic cells 2, protein (NM23B) expressed in, NM23-H2, NM23B or NDPKB, is identical to the beta subunit of human erythrocyte NDP kinase. Little to no expression was detected in other mouse tissues examined. Using Northern blot analysis, Masse et al. (2002) detected high expression of mouse Nme2, which they called nm23-M2, in heart, liver, and kidney, with intermediate expression in skeletal muscle. In situ hybridization of 15-day postcoitum mouse embryos showed ubiquitous Nme2 expression. The mouse and human NME2 genes contain 5 exons and span about 6.0 kb. The NME2 gene is mapped on 17q21.33. Srivastava et al. (2006) concluded that histidine phosphorylation regulates KCa3.1 channel activity and that NDPBK is critical to the channel activity and the activation of CD4 T cells.