PMID:21868624

Citation	Galindo, MM, Voigt, N, Stein, J, van Lengerich, J, Raguse, JD, Hofmann, T, Meyerhof, W and Behrens, M (2012) G protein-coupled receptors in human fat taste perception. Chem. Senses 37:123-39
Abstract	In contrast to carbohydrates and proteins, which are detected by specialized taste receptors in the forms of their respective building blocks, sugars, and L-amino acids, the third macronutrient, lipids, has until now not been associated with gustatory receptors. Instead, the recognition of fat stimuli was believed to rely mostly on textural, olfactory, and postingestive cues. During the recent years, however, research done mainly in rodent models revealed an additional gustatory component for the detection of long-chain fatty acids (LCFAs), the main taste-activating component of lipids. Concomitantly, a number of candidate fat taste receptors were proposed to be involved in rodent's gustatory fatty acid perception. Compared with rodent models, much less is known about human fat taste. In order to investigate the ability of the human gustatory system to respond to fat components, we performed sensory experiments with fatty acids of different chain lengths and derivatives thereof. We found that our panelists discriminated a "fatty" and an irritant "scratchy" taste component, with the "fatty" percept restricted to LCFAs. Using functional calcium-imaging experiments with the human orthologs of mouse candidate fat receptors belonging to the G protein-coupled receptor family, we correlated human sensory data with receptor properties characterized in vitro. We demonstrated that the pharmacological activation profile of human GPR40 and GPR120, 2 LCFA-specific receptors associated with gustatory fat perception in rodents, is inconsistent with the "scratchy" sensation of human subjects and more consistent with the percept described as "fatty." Expression analysis of GPR40 and GPR120 in human gustatory tissues revealed that, while the GPR40 gene is not expressed, GPR120 is detected in gustatory and nongustatory epithelia. On a cellular level, we found GPR120 mRNA and protein in taste buds as well as in the surrounding epithelial cells. We conclude that GPR120 may indeed participate in human gustatory fatty acid perception.
Links	PubMed Online version:10.1093/chemse/bjr069
Keywords	Alternative Splicing; Animals; Calcium/metabolism; Dose-Response Relationship, Drug; Fatty Acids/pharmacology; Gene Expression; HEK293 Cells; Humans; Kinetics; Mice; Protein Isoforms; RNA, Messenger/genetics; RNA, Messenger/metabolism; Receptors, G-Protein-Coupled/genetics; Receptors, G-Protein-Coupled/metabolism; Taste/physiology; Taste Buds/drug effects; Taste Buds/physiology; Taste Perception/drug effects; Taste Perception/physiology; Transfection
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
MOUSE:FFAR4		GO:0008289: lipid binding	ECO:0000269:		F		Long chain fatty acids are the main activating component of lipids. GPR120, a long chain fatty acid receptor. It is found in taste buds as well as surrounding epithelial cells.It plays a role in human gut fatty acid perception.	complete CACAO 6544

References

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