Gustducin-coupled receptor immplicated in the perception of bitter compounds in the oral cavity and the gastrointestinal tract. Signals through PLCB2 and the calcium-regulated cation channel TRPM5. Activated by the sulfonyl amide sweeteners saccharin and acesulfame K. In airway epithelial cells, binding of bitter compounds increases the intracellular calcium ion concentration and stimulates ciliary beat frequency. May acts as chemosensory receptors in airway epithelial cells to detect and eliminate potential noxious agents from the airways (By similarity).
