Anti-melatonin receptor 1B antibodies are used in the immunodetection of the protein encoded by the MTNR1B gene. In humans, the canonical protein has a reported length of 362 amino acid residues and a mass of 40.2 kDa. Its subcellular localization is in the cell membrane. It is reported to be expressed in retina and less in the brain and hippocampus. A member of the G-protein coupled receptor 1 protein family, it is a high affinity receptor for melatonin. Post-translational modifications have been described, including glycosylation. Other names for this target antigen include MEL-1B-R, MT2, melatonin receptor type 1B, mel1b receptor, melatonin receptor MEL1B, and FGQTL2.