TAS1R3 | |||||||||||||||||||||||||||||||||||||||||||||||||||
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Aliases | TAS1R3 , T1R3, taste 1 receptor member 3 | ||||||||||||||||||||||||||||||||||||||||||||||||||
External IDs | OMIM: 605865; MGI: 1933547; HomoloGene: 12890; GeneCards: TAS1R3; OMA:TAS1R3 - orthologs | ||||||||||||||||||||||||||||||||||||||||||||||||||
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Taste receptor type 1 member 3 is a protein that in humans is encoded by the TAS1R3 gene. [5] [6] The TAS1R3 gene encodes the human homolog of mouse Sac taste receptor, a major determinant of differences between sweet-sensitive and -insensitive mouse strains in their responsiveness to sucrose, saccharin, and other sweeteners. [6] [7]
The protein encoded by the TAS1R3 gene is a G protein-coupled receptor with seven trans-membrane domains and is a component of the heterodimeric amino acid taste receptor TAS1R1+3 and sweet taste receptor TAS1R2+3. This receptor is formed as a protein dimer with either TAS1R1 or TAS1R2. [8] Experiments have also shown that a homo-dimer of TAS1R3 is also sensitive to natural sugar substances. This has been hypothesized as the mechanism by which sugar substitutes do not have the same taste qualities as natural sugars. [9] [10]
APA</ref>
The G protein-coupled receptors for sweet and umami taste are formed by dimers of the TAS1R proteins. The TAS1R1+3 taste receptor is sensitive to the glutamate in monosodium glutamate (MSG) as well as the synergistic taste-enhancer molecules inosine monophosphate (IMP) and guanosine monophosphate (GMP). These taste-enhancer molecules are unable to activate the receptor alone, but are rather used to enhance receptor responses many to L-amino acids. [11] The TAS1R2+3 receptor has been shown to respond to natural sugars sucrose and fructose, and artificial sweeteners saccharin, acesulfame potassium, dulcin, guanidinoacetic acid. [8]
TAS1R2 and TAS1R1 receptors have been shown to bind to G proteins, most often the gustducin Gα subunit, although a gustducin knock-out has shown small residual activity. TAS1R2 and TAS1R1 have also been shown to activate Gαo and Gαi protein subunits. [12] This suggests that TAS1R1 and TAS1R2 are G protein-coupled receptors that inhibit adenylyl cyclases to decrease cyclic guanosine monophosphate (cGMP) levels in taste receptors. [13] The TAS1R3 protein, however, has been shown in vitro to couple with Gα subunits at a much lower rate than the other TAS1R proteins. While the protein structures of the TAS1R proteins are similar, this experiment shows that the G protein-coupling properties of TAS1R3 may be less important in the transduction of taste signals than the TAS1R1 and TAS1R2 proteins. [12]
TAS1R1+3 expressing cells are found in fungiform papillae at the tip and edges of the tongue and palate taste receptor cells in the roof of the mouth. [8] These cells are shown to synapse upon the chorda tympani nerves to send their signals to the brain. [11] TAS1R2+3 expressing cells are found in circumvallate papillae and foliate papillae near the back of the tongue and palate taste receptor cells in the roof of the mouth. [8] These cells are shown to synapse upon the glossopharyngeal nerves to send their signals to the brain. [14] [15] TAS1R and TAS2R (bitter) channels are not expressed together in any taste buds. [8]
TAS2R16 is a bitter taste receptor and one of the 25 TAS2Rs. TAS2Rs are receptors that belong to the G-protein-coupled receptors (GPCRs) family. These receptors detect various bitter substances found in nature as agonists, and get stimulated. TAS2R16 receptor is mainly expressed within taste buds present on the surface of the tongue and palate epithelium. TAS2R16 is activated by bitter β-glucopyranosides
A taste receptor or tastant is a type of cellular receptor that facilitates the sensation of taste. When food or other substances enter the mouth, molecules interact with saliva and are bound to taste receptors in the oral cavity and other locations. Molecules which give a sensation of taste are considered "sapid".
Gustducin is a G protein associated with taste and the gustatory system, found in some taste receptor cells. Research on the discovery and isolation of gustducin is recent. It is known to play a large role in the transduction of bitter, sweet and umami stimuli. Its pathways are many and diverse.
Taste receptor type 2 member 1 (TAS2R1/T2R1) is a protein that in humans is encoded by the TAS2R1 gene. It belongs to the G protein-coupled receptor (GPCR) family and is related to class A-like GPCRs, they contain 7 transmembrane helix bundles and short N-terminus loop. Furthermore, TAS2R1 is member of the 25 known human bitter taste receptors, which enable the perception of bitter taste in the mouth cavity. Increasing evidence indicates a functional role of TAS2Rs in extra-oral tissues.
Taste receptor type 2 member 3 is a protein that in humans is encoded by the TAS2R3 gene.
Taste receptor type 2 member 4 is a protein that in humans is encoded by the TAS2R4 gene.
Taste receptor type 2 member 8 is a protein that in humans is encoded by the TAS2R8 gene.
Taste receptor type 2 member 9 is a protein that in humans is encoded by the TAS2R9 gene.
Taste receptor type 2 member 10 is a protein that in humans is encoded by the TAS2R10 gene. The protein is responsible for bitter taste recognition in mammals. It serves as a defense mechanism to prevent consumption of toxic substances which often have a characteristic bitter taste.
Taste receptor type 2 member 13 is a protein that in humans is encoded by the TAS2R13 gene.
Taste receptor type 2 member 14 is a protein that in humans is encoded by the TAS2R14 gene.
Taste receptor type 2 member 5 is a protein that in humans is encoded by the TAS2R5 gene.
Taste receptor type 2 member 7 is a protein that in humans is encoded by the TAS2R7 gene.
Taste receptor type 1 member 1 is a protein that in humans is encoded by the TAS1R1 gene.
T1R2 - Taste receptor type 1 member 2 is a protein that in humans is encoded by the TAS1R2 gene.
Taste receptor type 2 member 39 is a protein that in humans is encoded by the TAS2R39 gene.
Taste receptor type 2 member 43 is a protein that in humans is encoded by the TAS2R43 gene.
Taste receptor, type 2, member 31, also known as TAS2R31, is a protein which in humans is encoded by the TAS2R31 gene. This bitter taste receptor has been shown to respond to saccharin in vitro.
Taste receptor type 2 member 20 is a protein that in humans is encoded by the TAS2R20 gene.
Taste receptor type 2 member 50 is a protein that in humans is encoded by the TAS2R50 gene.
This article incorporates text from the United States National Library of Medicine, which is in the public domain.