TAS2R16 | |||||||||||||||||||||||||||||||||||||||||||||||||||
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Aliases | TAS2R16 , T2R16, taste 2 receptor member 16, BGLPT | ||||||||||||||||||||||||||||||||||||||||||||||||||
External IDs | OMIM: 604867; MGI: 2681247; HomoloGene: 9660; GeneCards: TAS2R16; OMA:TAS2R16 - orthologs | ||||||||||||||||||||||||||||||||||||||||||||||||||
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TAS2R16 ( taste receptor, type 2, member 16) 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. [5] TAS2R16 is activated by bitter β-glucopyranosides (such as salicin) [6]
T2R16, Taste receptor 2 member 16, BGLPT.
The receptor is encoded by the TAS2R16 human gene which located on the long (q) arm of chromosome 7 at position 31.1-31.3, 997 bases. [7] [8] This gene is specifically expressed by taste receptor cells of the tongue and palate epithelia. Different individuals may have variations in the TAS2R16 gene, which can influence their sensitivity or preference for certain bitter compounds.
TAS2R16 consists of 291 amino acids. Molecular weight: 33,986 (Da). The receptor has 7 transmembrane helices, 3 intracellular loops and 3 extracellular loops. there are some conserved residues (black) and residues for which mutagenesis data is available. [9]
The function of TAS2R16 is to bind to specific bitter-tasting molecules present in various foods, plants, and potentially harmful substances. When binding to these molecules, TAS2R16 initiates a signaling cascade that leads to the transmission of signals to the brain, which results in the perception of bitterness. TAS2R16 specifically is believed to play a central role in determining human preference to eat or avoid such vegetables with bitter β-glucosides, important dietary choices that ultimately influence human health. [10]
The signaling pathway includes two essential components of the well-established taste signal transduction cascade: phospholipase C isoform β2 (PLCβ2) and the ion channel known as transient receptor potential cation channel subfamily M member 5 (TRPM5). [11] Ca2+-flux signaling assays are commonly used to measure the function of TAS2R16 and other GPCRs, so this measurement represents the key function of the receptor. [10]
There are 13 known ligands for TAS2R16. [12]
Diphenidol (synthetic) | D-salicin, Salicin |
Sodium Benzoate (synthetic) | Phenyl beta -D-glucopyranoside |
Amygdalin, D | Esculine Aesculin |
Arbutin | 2-Naphthyl beta-D-glucopyranoside |
Helicin | Methyl beta-D-glucoside |
sinigrin | 2-nitro phenyl beta -D-glucopyranoside |
The most well-studied natural ligand of TAS2R16 is salicin. In previous researches which analyzed how this receptor binds and signals, 38 residues that may be involved in signal transduction and 13 residues that contribute to ligand-specific interactions, were found to be involved. [10]
β-glucoside analogues are specific agonists of TAS2R16 in humans. These analogues, such as natural toxins, are molecular scafold consists of a D-glucose monosaccharide linked by an oxygen atom to a phenyl group. Arbutin was the first known natural inverse agonist for TAS2Rs. [5]
Many plants, including cruciferous vegetables such as broccoli and brussels sprouts, contain bitter β-glucosides such as salicin, sinigrin, arbutin, and amygdalin. [10]
Taste receptors harbor many polymorphisms, and several SNPs have a profound impact on the gene function and expression. [13]
Alleles | SNP ID |
---|---|
A > C, G | rs846664 |
C > T | rs860170 |
C > G, T | rs1204014 |
T > C, G | rs978739 |
A > C, T | rs846672 |
G > A, C, T | rs1308724 |
Recently studies have shown that mutation of the TAS2R16 gene could affect the intake of vegetables and anti-inflammatory food, which would influence age-related inflammatory diseases and increase the human lifespan. In addition, polymorphism of the TAS2R16 gene seems to affect body mass index, alcohol intake, smoking and drug compliance. Many bitter natural foods have the function of heat-clearing, detoxifying, anti-inflammatory, and antibacterial effects. [14]
Alcohol intake habits may be affected by the genetic diversity of taste preferences. [13] Alcohol dependence is significantly associated with the coding single-nucleotide polymorphism (cSNP) K172N in the gene hTAS2R16, which codes for a taste receptor for bitter b-glucopyranosides.This gene is found on chromosome 7q in a region that has been linked to alcoholism in some studies.The risk of alcohol use is higher in people with the ancestral gene K172. Individuals with this allele are at increased risk of alcohol dependence, regardless of ethnicity. However, this risk allele is rare in European Americans, but 45% of African Americans carry the allele, makes it a much more significant risk factor in the African American population. [15]
In a population of 941 individuals ranging from 60 to 106 years of age from the South of Italy, five significant associations between the SNPs in the chromosome 7 cluster and longevity was found, Three of them – observed in TAS2R16. SNP rs978739 showed a statistically significant association with longevity. The frequency of homozygotes A/A increases gradually from 35% in the subjects aged 20 to 70 up to 55% in centenarians. [16]
Taste receptor 2 member 38 is a protein that in humans is encoded by the TAS2R38 gene. TAS2R38 is a bitter taste receptor; varying genotypes of TAS2R38 influence the ability to taste both 6-n-propylthiouracil (PROP) and phenylthiocarbamide (PTC). Though it has often been proposed that varying taste receptor genotypes could influence tasting ability, TAS2R38 is one of the few taste receptors shown to have this function.
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 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 14 is a protein that in humans is encoded by the TAS2R14 gene.
T1R2 - Taste receptor type 1 member 2 is a protein that in humans is encoded by the TAS1R2 gene.
Taste receptor type 1 member 3 is a protein that in humans is encoded by the TAS1R3 gene. 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.
Taste receptor type 2 member 39 is a protein that in humans is encoded by the TAS2R39 gene.
Taste receptor type 2 member 40 is a protein that in humans is encoded by the TAS2R40 gene.
Taste receptor type 2 member 41 is a protein that in humans is encoded by the TAS2R41 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 45 is a protein that in humans is encoded by the TAS2R45 gene.
Taste receptors for bitter substances (T2Rs/TAS2Rs) belong to the family of G-protein coupled receptors and are related to class A-like GPCRs. There are 25 known T2Rs in humans responsible for bitter taste perception.
Taste receptor type 2 member 30 is a protein that in humans is encoded by the TAS2R30 gene.
Taste receptor type 2 member 19 is a protein that in humans is encoded by the TAS2R19 gene. It seems to be involved in the perception of salt and bitter tastes.
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.