# Sweet and umami TAS1R receptors: from molecular recognition to physiological function

## TL;DR

This review explains how sweet and umami taste receptors work and their role in detecting nutrients beyond the mouth.

## Contribution

The paper provides a comprehensive overview of TAS1R receptors from molecular recognition to physiological functions.

## Key findings

- TAS1R2/TAS1R3 and TAS1R1/TAS1R3 receptors detect sweet and umami tastes, respectively.
- These receptors are found in extraoral tissues, suggesting roles beyond taste perception.
- Structure–function analyses and evolution of TAS1R genes are summarized.

## Abstract

The detection of sweet and umami tastants is mediated by 2 heterodimeric G protein-coupled receptors, TAS1R2/TAS1R3 and TAS1R1/TAS1R3, respectively. Sweet taste provides input related to the carbohydrate-derived energy content of ingested food, whereas the physiological role of umami taste by detecting free L-amino acids is to signal the presence of protein-rich foods. In addition to being expressed in the oral cavity, TAS1R receptors are expressed in numerous extraoral tissues and organs, including the gut, where their physiological roles are not yet fully understood. In this review, we present an overview of the current knowledge on these taste receptors since their discovery in the early 2000s. We summarize the structure–function analyses, evolution, and expression of TAS1R genes and describe the molecular basis for the recognition of sweet and umami tastants. Together, these insights provide a comprehensive understanding of how TAS1R receptors contribute to nutrient detection and metabolic regulation both in taste perception and beyond.