Taste receptor type 1 member 2 / Taste receptor type 1 member 3 heterodimer (T1R2/T1R3 heterodimer)

The **Taste receptor type 1 member 2 / Taste receptor type 1 member 3 heterodimer** is a class C G protein-coupled receptor complex responsible for mediating the sensation of sweetness in humans and other vertebrates. This functional unit consists of two subunits—T1R2 and T1R3—that must form a heterodimer at the cell surface to recognize a wide range of natural sugars, artificial sweeteners (such as aspartame, neotame, cyclamate), D-amino acids, and certain plant-derived proteins like brazzein and thaumatin. Each subunit contributes distinct ligand-binding sites: T1R2 primarily recognizes carbohydrate-based ligands through its N-terminal extracellular domain while T1R3 provides additional binding specificity via its transmembrane region. Upon ligand binding, conformational changes propagate through both extracellular Venus flytrap domains and transmembrane helices into intracellular regions that couple with G-proteins—initiating downstream signaling cascades responsible for transmitting "sweet" signals from taste buds to sensory neurons. Beyond gustation, these receptors have roles in nutrient sensing throughout the digestive system. Their broad ligand recognition profile makes them important targets for designing novel non-caloric sweeteners aimed at reducing caloric intake—a strategy relevant for obesity and diabetes management.

Other names

Sweet taste receptorT1R2-T1R3TAS1R2/TAS1R3 (gene/protein nomenclature)Heteromeric sweet taste receptor

Drugs or compounds act as agonists or antagonists by binding to specific domains of the heterodimer, triggering conformational changes that activate intracellular G-protein signaling pathways. For example, aspartame binds to the N-terminal domain of T1R2; cyclamate interacts with the transmembrane domain of T1R3; lactisole acts as an inhibitor via the same region on T1R3. These interactions modulate signal transduction leading to perception of sweetness or inhibition thereof.