The transmembrane domain of T1R3 contains specific amino acid residues essential for responding to certain sweeteners like cyclamate.

Research shows that the T1R3 subunit’s transmembrane part has key amino acids that determine whether it can detect artificial sweeteners such as cyclamate. Mutations in these residues can abolish the receptor’s ability to respond, highlighting this domain’s critical role in sweet taste recognition beyond the extracellular binding sites.