NME1 and neuroblastoma: Immunoblot screening of a panel of established human neuroblastoma cell lines demonstrated both histidine phosphorylation of NME1 and NME2 (Figure 2A) and phosphorylated histidine residues on a number of other unidentified proteins, with phosphorylation at both the 1 (1-pHis) and 3 (3-pHis) isomer sites, for which the conformations have been illustrated previously [33].