Human receptors for sweet and umami taste

TLDR

The T1R family of taste‑specific G protein‑coupled receptors is thought to form heterodimers that mediate sweet taste. Human T1R2/T1R3 detects diverse sweeteners, while T1R1/T1R3 responds to l‑glutamate and 5′‑ribonucleotides, indicating that T1Rs mediate both sweet and umami tastes and share a common subunit.

Abstract

The three members of the T1R class of taste-specific G protein-coupled receptors have been hypothesized to function in combination as heterodimeric sweet taste receptors. Here we show that human T1R2/T1R3 recognizes diverse natural and synthetic sweeteners. In contrast, human T1R1/T1R3 responds to the umami taste stimulus l -glutamate, and this response is enhanced by 5′-ribonucleotides, a hallmark of umami taste. The ligand specificities of rat T1R2/T1R3 and T1R1/T1R3 correspond to those of their human counterparts. These findings implicate the T1Rs in umami taste and suggest that sweet and umami taste receptors share a common subunit.