Taste receptor type 1 member 3 (TAS1R3) (TAS1R3)

Taste receptor type 1 member 3 (TAS1R3) is a Class C G protein-coupled receptor that plays a fundamental role in the mammalian sensory system and metabolic regulation. It is a versatile subunit that heterodimerizes with TAS1R2 to detect sweet substances and with TAS1R1 to detect umami-tasting L-amino acids [UniProt Q7RTX0]. While primarily known for its presence in taste buds on the tongue, TAS1R3 is also widely expressed in extra-oral tissues such as the gastrointestinal tract, pancreas, and liver, where it functions as a nutrient sensor [PubMed: 30635443]. In these locations, it monitors luminal glucose levels and triggers the release of metabolic hormones like insulin and glucagon-like peptide-1 (GLP-1), making it a significant factor in energy homeostasis [PubMed: 22131553]. Consequently, TAS1R3 is a target of interest for pharmacological interventions in metabolic diseases, including obesity and type 2 diabetes [PubMed: 29203014]. Its activity is modulated by a wide range of ligands, from natural sugars and artificial sweeteners to specific antagonists like lactisole, which are used to study taste physiology and develop therapeutic strategies [PubChem].

Other names

T1R3TR3G-protein coupled receptor 71GPR71Sweet taste receptor subunit 3

TAS1R3 functions as a mandatory subunit in heterodimeric complexes; it pairs with TAS1R2 to form the sweet taste receptor and with TAS1R1 to form the umami taste receptor [UniProt Q7RTX0]. Upon ligand binding (e.g., sugars or sweeteners), the receptor activates the heterotrimeric G-protein gustducin (Gnat3), which triggers a signaling cascade involving phospholipase C beta-2 (PLC-beta-2) and the inositol trisphosphate receptor type 3 (IP3R3), leading to the release of intracellular calcium [PubMed: 11331882]. This calcium increase opens the TRPM5 ion channel, causing cell depolarization and the release of ATP as a neurotransmitter to signal taste to the brain [PubMed: 12594509]. In extra-oral tissues like the gut and pancreas, this same signaling pathway modulates the secretion of metabolic hormones such as GLP-1 and insulin [PubMed: 22131553].