title: Tas1R1-Tas1R3 taste receptor variants in human fungiform papillae.
abstract: Monosodium glutamate as well as metabotropic and ionotropic glutamate receptor agonists have been reported to be perceived as umami by humans. In spite of the fact that Tas1R1-Tas1R3 has been shown to mediate most of the glutamate taste sensation in mice other candidate receptors have been put forward for which a clear role in detection is still lacking. This work was aimed at investigating the molecular determinants underlying umami taste detection in humans. First, we show evidence supporting expression of Tas1R1 and Tas1R3 but not mGluRs in the fungiform papillae of several individuals. Next, we report a number of naturally occurring L-glutamate taste receptor variants and their frequency in a population of Caucasian subjects. Detailed analysis of 9 non-synonymous single nucleotide polymorphisms from three L-glutamate taste GPCR candidates uncovers receptor specific clusters such that all substitutions in Tas1R1 are located in the extracellular N-terminal ligand-binding domain while in Tas1R3 they mostly affect residues in the seven transmembrane-spanning core domain responsible for the interaction with antagonists and allosteric modulators. In mGluR1, nsSNPs identified are clustered in the intracellular C-terminal tail, which is thought to play a role in signaling. Taken together, these results suggest that Tas1R1-Tas1R3 receptor variants found in human fungiform papillae might contribute to inter-individual differences of sensitivity to L-glutamate.
authors.affiliation: UMR5170 Centre des Sciences du Goût, CNRS-INRA-Université de Bourgogne, 15 Rue H. Picardet, Dijon, F-21000, France; CNRS, INRA, UMR1197 NOPA-Neurobiologie Sensorielle, F-78350 Jouy en Josas, France; Univ Paris-Sud, Orsay, F-91405, France.
authors.forename: Mariam
authors.initials: M
authors.lastname: Raliou
authors.forename: Yves
authors.initials: Y
authors.lastname: Boucher
authors.forename: Anna
authors.initials: A
authors.lastname: Wiencis
authors.forename: Valérie
authors.initials: V
authors.lastname: Bézirard
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Pernollet
authors.forename: Didier
authors.initials: D
authors.lastname: Trotier
authors.forename: Annick
authors.initials: A
authors.lastname: Faurion
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Montmayeur
mesh_terms: D000328:Adult; D000368:Aged; D000494:Allosteric Regulation / Q000235:genetics; D001665:Binding Sites; D005260:Female; D014644:Genetic Variation / Q000235:genetics; D018698:Glutamic Acid / Q000378:metabolism* / Q000494:pharmacology; D006801:Humans; D008024:Ligands; D008297:Male; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary / Q000235:genetics; D043562:Receptors, G-Protein-Coupled / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D018094:Receptors, Metabotropic Glutamate / Q000737:chemistry / Q000378:metabolism; D013649:Taste / Q000235:genetics*; D013650:Taste Buds / Q000187:drug effects / Q000502:physiology*; D013652:Taste Threshold / Q000235:genetics; D014059:Tongue / Q000294:innervation / Q000502:physiology*
chemical_list: D008024:Ligands; D020033:Protein Isoforms; D043562:Receptors, G-Protein-Coupled; D018094:Receptors, Metabotropic Glutamate; C104077:metabotropic glutamate receptor type 1; C431926:taste receptors, type 1; D018698:Glutamic Acid