Protein histidine phosphatase: a novel enzyme with potency for neuronal signaling.

The importance of reversible phosphorylation for neuronal signaling and cell survival is well recognized. Knowledge in vertebrates, however, is so far limited to O-phosphates from serine, threonine, and tyrosine. The authors describe an enzyme acting on N-phosphates. It is the first protein histidine phosphatase identified in vertebrates. This histidine phosphatase is ubiquitously expressed in mammalian tissues including brain. Characterization and sequencing showed a yet unknown protein with no similarity to other phosphatases. In Caenorhabditis elegans, the homolog of this histidine phosphatase was exclusively expressed in neurons, suggesting a distinct role of reversible histidine phosphorylation in neuronal functions.