G protein-coupled receptor 81 (FKSG80) belongs to the G protein-coupled receptor 1 family. It is an integral membrane protein which functions as an orphan receptor. The gene encoding the FKSG80 protein, GPR81, maps to chromosome 12q24.31 in humans. The FKSG80 protein is a 347 amino acid protein that shares 70% homology to the chemokine receptor HM74. FKSG80 is expressed mainly in pituitary, but can also be detected in adipose tissue. It is not found in hippocampus, basal forebrain, frontal, temporal and occipital lobes of the cortex, caudate nucleus or nucleus accumbens.