GPR156 (G protein-coupled receptor 156), is a human gene which encodes a G protein-coupled receptor belonging to metabotropic glutamate receptor subfamily. By sequence homology, this gene was proposed as being a possible GABAB receptor subunit, however when expressed in cells alone or with other GABAB subunits, no response to GABAB ligands could be detected. In vitro studies on GPR156 constitutive activity revealed a high level of basal activation and coupling with members of the Gi/Go heterotrimeric G protein family. In 2021, an article was reported that GPR156 modulates hair cell orientation in the cochlea. Also, it was proposed that GPR156 is related to congenital hearing loss. GPR156 in complex with any of the Gi/o heterotrimers regulates the hair cell orientation. In 2024, molecular structures of G-free and Go-bound GPR156 were characterized by using cryogenic electron microscopy.
