Taste receptor type 1 member 1 is a protein that in humans is encoded by the TAS1R1 gene.

The protein encoded by the TAS1R1 gene is a G protein-coupled receptor with seven trans-membrane domains and is a component of the heterodimeric amino acid taste receptor T1R1+3. This receptor is formed as a dimer of the TAS1R1 and TAS1R3 proteins. Moreover, the TAS1R1 protein is not functional outside of formation of the 1+3 heterodimer. The TAS1R1+3 receptor has been shown to respond to L-amino acids but not to their D-enantiomers or other compounds. This ability to bind L-amino acids, specifically L-glutamine, enables the body to sense the umami, or savory, taste. Multiple transcript variants encoding several different isoforms have been found for this gene, which may account for differing taste thresholds among individuals for the umami taste. Another interesting quality of the TAS1R1 and TAS1R2 proteins is their spontaneous activity in the absence of the extracellular domains and binding ligands. This may mean that the extracellular domain regulates function of the receptor by preventing spontaneous action as well as binding to activating ligands such as L-glutamine.