A collaborative effort between Howard Hughes Medical Institute researchers at the University of California, San Diego and scientists at the National Institute of Dental and Craniofacial Research (NIDCR), National Institutes of Health (NIH), have identified the genes likely responsible for the mammalian sense of taste.
In the Feb. 19 issue of the scientific journal Cell, the researchers describe genes that encode two novel proteins expressed in cells specifically geared to the sense of taste. The proteins, members of a new group of "G protein" receptors, were singled out as a result of their unique expression in taste buds of the tongue and palate epithelium.
The isolation of the candidate taste receptor genes provides the groundwork necessary for manipulating the perception of taste and devising methods to stimulate or block taste cell function. The identification also sets the stage for a comprehensive physiological investigation of how the sense of taste is "wired" from the mouth to the brain.
"The identity of the receptor molecules for the different sensory modalities, like vision, olfaction and taste, represents the Holy Grail of the sensory field," said UCSD Professor Charles Zuker, principal co-author of the report. "These receptor molecules provide the unique specificity and selectivity of each sensory system. The color receptors in our retinas allow us to see in color and the olfactory receptors in our nose endow us with great olfactory discrimination. In the case of taste, they are what make sweet cells respond to sweet substances, bitter cells to bitter compounds, and so on."
"These two molecules have the hallmarks we expect of taste receptors," said co-investigator Nicholas Ryba of NIDCR. "They may be the key to unlocking our understanding of how we detect taste, which is unclear at the moment. We must now demonstrate that functionally they can do the job."