TAS2R9 belongs to the family of candidate taste receptors that are members of the G-protein-coupled receptor superfamily. These proteins are specifically expressed in the taste receptor cells of the tongue and palate epithelia. They are organized in the genome in clusters and are genetically linked to loci that influence bitter perception in mice and humans. In functional expression studies, they respond to bitter tastants. This gene maps to the taste receptor gene cluster on chromosome 12p13.
TAS2R9 is implicated in the perception of bitter compounds in the oral cavity and the gastrointestinal tract. It signals through PLCB2 and the calcium regulated cation channel TRPM5.