Fig. 2.

Overview of the canonical TAS2R signalling pathway. Upon TAS2R activation, the G-protein gustducin dissociates and activates phopholipase Cβ2 (PLCβ2), which subsequently leads to elevation in Ca²⁺ from inositol-1,4,5-triphosphate (IP3)-sensitive Ca²⁺ stores. This in turn activates transient receptor potential cation channel subfamily M member 5 (TRPM5), alters membrane potential (depolarisation), and triggers the release of the neurotransmitter, adenosine-5'-triphosphate (ATP), via the calcium homeostasis modulator 1 CALHM1 or CALHM1/CALHM3 ion channel. All these events together contribute to a wide range of cellular response