InterPro domain: IPR038596

This superfamily is comprised of the 14kDa phosphohistidine phosphatase from mammals and Janus-A/Janus-B proteins from Drosophila melanogaster. Janus-A and Janus-B regulate somatic sex differentiation and have been found to be testes specific [ 1 ]. 14kDa phosphohistidine phosphatase is a histidine phosphatase that may play a role of reversible histidine phosphorylation in neuronal functions [ 2 ].

The 14kDa phosphohistidine phosphatase is of a novel topology, and the structure reveals a positively charged active site defined by conserved residues that provide a suitable environment for binding phosphohistidine-containing substrates [ 3 ].

1. Molecular evolution of the ocnus and janus genes in the Drosophila melanogaster species subgroup. Mol. Biol. Evol. 18, 801-11
2. Protein histidine phosphatase: a novel enzyme with potency for neuronal signaling. J. Cereb. Blood Flow Metab. 22, 1420-4
3. First structure of a eukaryotic phosphohistidine phosphatase. J. Biol. Chem. 281, 33830-4