TAS1R3 (taste 1 receptor member 3) is a crucial subunit of class C G-protein-coupled receptors that mediates both sweet and umami taste perception. TAS1R3 forms heterodimers with TAS1R2 to create the sweet taste receptor complex and with TAS1R1 to form the umami taste receptor 12. The TAS1R2/TAS1R3 heterodimer recognizes diverse sweeteners including sucrose, artificial sweeteners like sucralose, and even heavy water (D2O), with sucralose binding specifically to the Venus flytrap domain of TAS1R2 12. Beyond canonical taste functions, TAS1R3 demonstrates remarkable functional diversity. It can form homodimers in osteoclasts to detect glucose and regulate bone resorption 3, and heterodimerize with mGlu2 receptors in immune cells to modulate neutrophil responses 4. The receptor also responds to inosine-5'-monophosphate (IMP), which enhances sweet taste detection through the TAS1R3 subunit 5. Genetic polymorphisms in TAS1R3 contribute to individual differences in taste sensitivity, with specific variants affecting glutamate perception 6. TAS1R3 is expressed in extraoral tissues including the gastrointestinal tract, pancreas, and immune cells, where it contributes to glucose homeostasis and immune function 74.