Activation Profile of TAS2R2, the 26th Human Bitter Taste Receptor

Area of Science:

• Genetics
• Molecular Biology
• Sensory Science

Background:

• Humans possess approximately 25 bitter taste receptor (TAS2R) genes in oral taste cells to detect potentially harmful substances.
• Genetic variations (polymorphisms) in TAS2R genes contribute to significant differences in bitter taste perception among individuals.
• The TAS2R2 gene was previously considered a non-functional pseudogene, limiting the known repertoire of bitter taste receptors.

Purpose of the Study:

• To investigate the functional role of the TAS2R2 bitter taste receptor, which has been largely overlooked in previous research.
• To characterize the specific bitter compounds that activate the TAS2R2 receptor.
• To determine the TAS2R2 receptor's place within the broader family of TAS2Rs based on its agonist profile.

Main Methods:

• A functional screening assay was conducted using a panel of 122 distinct bitter compounds.
• The study measured the response of the TAS2R2 receptor to each compound in the screening.
• Specific bitter substances that elicited a response from TAS2R2 were identified and analyzed.

Main Results:

• The TAS2R2 receptor responded to eight out of the 122 tested bitter substances.
• Phenylbutazone was identified as a novel and unique activator of the TAS2R2 receptor among all known TAS2Rs.
• This finding helps to fill a gap in the understanding of which bitter compounds activate specific TAS2Rs.

Conclusions:

• The TAS2R2 receptor has a medium-sized repertoire of bitter agonists, classifying it among other known TAS2Rs.
• The discovery of a functional TAS2R2 and its activators suggests that the variability in bitter taste perception across human populations may be greater than previously assumed.
• This research contributes to a more complete understanding of the genetic basis of bitter taste and its potential impact on dietary preferences.