Guanine nucleotide-binding protein G(z) subunit alpha, also known as GNAZ, is a member of a G protein subfamily that mediates signal transduction in pertussis toxin-insensitive systms. This protein may play a role in maintaining the ionic balance of perilymphatic and endolymphatic cochlear fluids. Recombinant human GNAZ protein, fused to His-tag at N-terminus, was expressed in E.coli.