This gene encodes an enzyme that catalyzes the reversible dephosphorylation of histidine residues in proteins. It may be involved in the dephosphorylation of G-beta and ATP citrate lyase and in negatively regulating CD4 T lymphocytes by dephosphorylation and inhibition of KCa3.1 channels. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Dec 2013].