Peptide interactions with taste receptors: Overlap in taste receptor specificity

1984 ◽  
Vol 40 (8) ◽  
pp. 843-844 ◽  
Author(s):  
R. H. Cagan
Keyword(s):  
Taste Receptor ◽  
Taste Receptors ◽  
Receptor Specificity ◽  
Peptide Interactions

scholarly journals Role of Taste Receptors as Sentinels of Innate Immunity in the Upper Airway

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Neil N. Patel ◽  
Alan D. Workman ◽  
Noam A. Cohen
Keyword(s):  
Airway Epithelium ◽  
Taste Receptor ◽  
Upper Airway ◽  
Airway Disease ◽  
G Protein Coupled Receptors ◽  
Innate Immune ◽  
Taste Receptors ◽  
Taste Sensation ◽  
G Protein Coupled

Evidence is emerging that shows taste receptors serve functions outside of taste sensation of the tongue. Taste receptors have been found in tissue across the human body, including the gastrointestinal tract, bladder, brain, and airway. These extraoral taste receptors appear to be important in modulating the innate immune response through detection of pathogens. This review discusses taste receptor signaling, focusing on the G-protein–coupled receptors that detect bitter and sweet compounds in the upper airway epithelium. Emphasis is given to recent studies which link the physiology of sinonasal taste receptors to clinical manifestation of upper airway disease.

scholarly journals Genetics of sweet taste preferences

2002 ◽  
Vol 74 (7) ◽  
pp. 1135-1140 ◽  
Author(s):  
Alexander A. Bachmanov ◽  
Danielle R. Reed ◽  
Xia Li ◽  
Gary K. Beauchamp
Keyword(s):  
Positional Cloning ◽  
Inbred Mouse ◽  
Taste Receptor ◽  
Sweet Taste ◽  
Mouse Strains ◽  
Taste Receptors ◽  
Chromosome 4 ◽  
Sweet Taste Receptor ◽  
Distal Chromosome ◽  
Allelic Differences

Inbred mouse strains display marked differences in avidity for sweet solutions due in part to genetic differences among strains. Using several techniques, we have located a number of regions throughout the genome that influence sweetener acceptance. One prominent locus regulating differences in sweetener preferences among mouse strains is the saccharin preference (Sac) locus on distal chromosome 4. Afferent responses of gustatory nerves to sweeteners also vary as a function of allelic differences in the Sac locus, suggesting that this gene may encode a sweet taste receptor. Using a positional cloning approach, we identified a gene (Tas1r3) encoding the third member of the T1R family of putative taste receptors, T1R3. Introgression by serial back-crossing of a chromosomal fragment containing the Tas1r3 allele from the high sweetener-preferring strain onto the genetic background of the low sweetener-preferring strain rescued its low sweetener-preference phenotype. Tas1r3 has two common haplotypes, one found in mouse strains with elevated sweetener preference and the other in strains relatively indifferent to sweeteners. This study, in conjunction with complimentary recent studies from other laboratories, provides compelling evidence that Tas1r3 is equivalent to the Sac locus and that the T1R3 receptor (when co-expressed with taste receptor T1R2) responds to sweeteners. However, other sweetness receptors may remain to be identified.

scholarly journals Expression of Taste Receptor 2 Subtypes in Human Testis and Sperm

2020 ◽  
Vol 9 (1) ◽  
pp. 264 ◽  
Author(s):  
Laura Governini ◽  
Bianca Semplici ◽  
Valentina Pavone ◽  
Laura Crifasi ◽  
Camilla Marrocco ◽  
...  
Keyword(s):  
Taste Receptor ◽  
Receptor Activation ◽  
Taste Buds ◽  
The Body ◽  
Semen Parameters ◽  
Human Testis ◽  
Taste Receptors ◽  
Organ Systems

Taste receptors (TASRs) are expressed not only in the oral cavity but also throughout the body, thus suggesting that they may play different roles in organ systems beyond the tongue. Recent studies showed the expression of several TASRs in mammalian testis and sperm, indicating an involvement of these receptors in male gametogenesis and fertility. This notion is supported by an impaired reproductive phenotype of mouse carrying targeted deletion of taste receptor genes, as well as by a significant correlation between human semen parameters and specific polymorphisms of taste receptor genes. To better understand the biological and thus clinical significance of these receptors for human reproduction, we analyzed the expression of several members of the TAS2Rs family of bitter receptors in human testis and in ejaculated sperm before and after in vitro selection and capacitation. Our results provide evidence for the expression of TAS2R genes, with TAS2R14 being the most expressed bitter receptor subtype in both testis tissue and sperm cells, respectively. In addition, it was observed that in vitro capacitation significantly affects both the expression and the subcellular localization of these receptors in isolated spermatozoa. Interestingly, α-gustducin and α-transducin, two Gα subunits expressed in taste buds on the tongue, are also expressed in human spermatozoa; moreover, a subcellular redistribution of both G protein α-subunits to different sub-compartments of sperm was registered upon in vitro capacitation. Finally, we shed light on the possible downstream transduction pathway initiated upon taste receptor activation in the male reproductive system. Performing ultrasensitive droplets digital PCR assays to quantify RNA copy numbers of a distinct gene, we found a significant correlation between the expression of TAS2Rs and TRPM5 (r = 0.87), the cation channel involved in bitter but also sweet and umami taste transduction in taste buds on the tongue. Even if further studies are needed to clarify the precise functional role of taste receptors for successful reproduction, the presented findings significantly extend our knowledge of the biological role of TAS2Rs for human male fertility.

scholarly journals Taste receptor polymorphisms and longevity: a systematic review and meta-analysis

2020 ◽  
Author(s):  
Danilo Di Bona ◽  
Alberto Malovini ◽  
Giulia Accardi ◽  
Anna Aiello ◽  
Giuseppina Candore ◽  
...  
Keyword(s):  
Systematic Review ◽  
Bitter Taste ◽  
Meta Analysis ◽  
Taste Receptor ◽  
The Other ◽  
Analytic Approach ◽  
Taste Receptors ◽  
South Italy ◽  
Physiological Processes ◽  
Different Populations

AbstractBitter taste receptors (TAS2R) are involved in a variety of non-tasting physiological processes, including immune-inflammatory ones. Therefore, their genetic variations might influence various traits. In particular, in different populations of South Italy (Calabria, Cilento, and Sardinia), polymorphisms of TAS2R16 and TAS238 have been analysed in association with longevity with inconsistent results. A meta-analytic approach to quantitatively synthesize the possible effect of the previous variants and, possibly, to reconcile the inconsistencies has been used in the present paper. TAS2R38 variants in the Cilento population were also analysed for their possible association with longevity and the obtained data have been included in the relative meta-analysis. In population from Cilento no association was found between TAS2R38 and longevity, and no association was observed as well, performing the meta-analysis with data of the other studies. Concerning TAS2R16 gene, instead, the genotype associated with longevity in the Calabria population maintained its significance in the meta-analysis with data from Cilento population, that, alone, were not significant in the previously published study. In conclusion, our results suggest that TAS2R16 genotype variant is associated with longevity in South Italy.

scholarly journals Sweet Taste Receptor Signaling Network: Possible Implication for Cognitive Functioning

2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
Menizibeya O. Welcome ◽  
Nikos E. Mastorakis ◽  
Vladimir A. Pereverzev
Keyword(s):  
Cognitive Functioning ◽  
Transmembrane Protein ◽  
Taste Receptor ◽  
Sweet Taste ◽  
The Body ◽  
Taste Receptors ◽  
Receptor Signaling ◽  
Sweet Taste Receptor ◽  
Sweet Taste Receptors

Sweet taste receptors are transmembrane protein network specialized in the transmission of information from special “sweet” molecules into the intracellular domain. These receptors can sense the taste of a range of molecules and transmit the information downstream to several acceptors, modulate cell specific functions and metabolism, and mediate cell-to-cell coupling through paracrine mechanism. Recent reports indicate that sweet taste receptors are widely distributed in the body and serves specific function relative to their localization. Due to their pleiotropic signaling properties and multisubstrate ligand affinity, sweet taste receptors are able to cooperatively bind multiple substances and mediate signaling by other receptors. Based on increasing evidence about the role of these receptors in the initiation and control of absorption and metabolism, and the pivotal role of metabolic (glucose) regulation in the central nervous system functioning, we propose a possible implication of sweet taste receptor signaling in modulating cognitive functioning.

scholarly journals In Silico Molecular Study of Tryptophan Bitterness

Molecules ◽  
2020 ◽  
Vol 25 (20) ◽  
pp. 4623
Author(s):  
Antonella Di Pizio ◽  
Alessandro Nicoli
Keyword(s):  
Amino Acid ◽  
Molecular Modeling ◽  
In Silico ◽  
Essential Amino Acid ◽  
Bitter Taste ◽  
Taste Receptor ◽  
Molecular Study ◽  
Taste Receptors ◽  
Bitter Taste Receptor ◽  
The Core

Tryptophan is an essential amino acid, required for the production of serotonin. It is the most bitter amino acid and its bitterness was found to be mediated by the bitter taste receptor TAS2R4. Di-tryptophan has a different selectivity profile and was found to activate three bitter taste receptors, whereas tri-tryptophan activated five TAS2Rs. In this work, the selectivity/promiscuity profiles of the mono-to-tri-tryptophans were explored using molecular modeling simulations to provide new insights into the molecular recognition of the bitter tryptophan. Tryptophan epitopes were found in all five peptide-sensitive TAS2Rs and the best tryptophan epitope was identified and characterized at the core of the orthosteric binding site of TAS2R4.

scholarly journals G Protein-Coupled Receptors in Taste Physiology and Pharmacology

2020 ◽  
Vol 11 ◽  
Author(s):  
Raise Ahmad ◽  
Julie E. Dalziel
Keyword(s):  
Binding Site ◽  
G Protein ◽  
Molecular Mechanisms ◽  
Taste Receptor ◽  
Receptor Activation ◽  
G Protein Coupled Receptors ◽  
Type I ◽  
Taste Receptors ◽  
Agonist Binding ◽  
G Protein Coupled

Heterotrimeric G protein-coupled receptors (GPCRs) comprise the largest receptor family in mammals and are responsible for the regulation of most physiological functions. Besides mediating the sensory modalities of olfaction and vision, GPCRs also transduce signals for three basic taste qualities of sweet, umami (savory taste), and bitter, as well as the flavor sensation kokumi. Taste GPCRs reside in specialised taste receptor cells (TRCs) within taste buds. Type I taste GPCRs (TAS1R) form heterodimeric complexes that function as sweet (TAS1R2/TAS1R3) or umami (TAS1R1/TAS1R3) taste receptors, whereas Type II are monomeric bitter taste receptors or kokumi/calcium-sensing receptors. Sweet, umami and kokumi receptors share structural similarities in containing multiple agonist binding sites with pronounced selectivity while most bitter receptors contain a single binding site that is broadly tuned to a diverse array of bitter ligands in a non-selective manner. Tastant binding to the receptor activates downstream secondary messenger pathways leading to depolarization and increased intracellular calcium in TRCs, that in turn innervate the gustatory cortex in the brain. Despite recent advances in our understanding of the relationship between agonist binding and the conformational changes required for receptor activation, several major challenges and questions remain in taste GPCR biology that are discussed in the present review. In recent years, intensive integrative approaches combining heterologous expression, mutagenesis and homology modeling have together provided insight regarding agonist binding site locations and molecular mechanisms of orthosteric and allosteric modulation. In addition, studies based on transgenic mice, utilizing either global or conditional knock out strategies have provided insights to taste receptor signal transduction mechanisms and their roles in physiology. However, the need for more functional studies in a physiological context is apparent and would be enhanced by a crystallized structure of taste receptors for a more complete picture of their pharmacological mechanisms.

scholarly journals Receptor Regulation in Taste: Can Diet Influence How We Perceive Foods?

J ◽  
2018 ◽  
Vol 1 (1) ◽  
pp. 106-115 ◽  
Author(s):  
Ashkan Shahbandi ◽  
Ezen Choo ◽  
Robin Dando
Keyword(s):  
Chronic Exposure ◽  
Taste Receptor ◽  
Receptor Expression ◽  
Receptor Regulation ◽  
Taste Receptors ◽  
Receptor Sensitivity ◽  
Small Pilot Study ◽  
Monosodium Salt ◽  
The Impact

Taste buds are the dedicated sensory end organs of taste, comprising a complex and evolving profile of signaling elements. The sensation and ultimate perception of taste depends on the expression of a diverse array of receptors and channels that sense their respective tastes. Receptor regulation is a recognized and well-studied phenomenon in many systems, observed in opioid addiction, insulin resistance and caffeine tolerance. Results from human sensory studies suggest that receptor sensitivity or expression level may decrease after chronic exposure to respective tastants through diet. We review data supporting the theory that taste receptors may become downregulated with exposure to a specific tastant, along with presenting data from a small pilot study, showing the impact of long-term tastant exposure on taste receptor expression in mice. Mice treated with monosodium salt monohydrate (MSG), saccharin and NaCl (typically appetitive tastes) all displayed a significant decrease in mRNA expression for respective umami, sweet and salty receptors/sensory channels. Reduced sensitivity to appetitive tastes may promote overconsumption of foods high in such stimuli.

Taste Receptors in the Gastrointestinal Tract. I. Bitter taste receptors and α-gustducin in the mammalian gut

2006 ◽  
Vol 291 (2) ◽  
pp. G171-G177 ◽  
Author(s):  
Enrique Rozengurt
Keyword(s):  
Bitter Taste ◽  
Critical Role ◽  
Taste Receptor ◽  
Caloric Intake ◽  
Taste Receptors ◽  
Neural Pathways ◽  
Gi Tract ◽  
Lingual Epithelium ◽  
Molecular Sensing ◽  
Pancreatic Insulin

Molecular sensing by gastrointestinal (GI) cells plays a critical role in the control of multiple fundamental functions in digestion and also initiates hormonal and/or neural pathways leading to the regulation of caloric intake, pancreatic insulin secretion, and metabolism. Molecular sensing in the GI tract is also responsible for the detection of ingested harmful drugs and toxins, thereby initiating responses critical for survival. The initial recognition events and mechanism(s) involved remain incompletely understood. The notion to be discussed in this article is that there are important similarities between the chemosensensory machinery elucidated in specialized neuroepithelial taste receptor cells of the lingual epithelium and the molecular transducers localized recently in enteroendocrine open GI cells that sense the chemical composition of the luminal contents of the gut.

scholarly journals Multiple loss-of-function variants of taste receptors in modern humans

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Kohei Fujikura
Keyword(s):  
Human Genome ◽  
Mammalian Species ◽  
Taste Receptor ◽  
Population Diversity ◽  
Taste Receptors ◽  
Loss Of Function ◽  
Modern Humans ◽  
Variant Frequency ◽  
Molecular Evolutionary Rates ◽  
Multiple Loss

Abstract Despite recent advances in the knowledge of interindividual taste differences, the underlying genetic backgrounds have remained to be fully elucidated. Much of the taste variation among different mammalian species can be explained by pseudogenization of taste receptors. Here I investigated whether the most recent disruptions of taste receptor genes segregate with their intact forms in modern humans by analyzing 14 ethnically diverse populations. The results revealed an unprecedented prevalence of 25 segregating loss-of-function (LoF) taste receptor variants, identifying one of the most pronounced cases of functional population diversity in the human genome. LoF variant frequency in taste receptors (2.10%) was considerably higher than the overall LoF frequency in human genome (0.16%). In particular, molecular evolutionary rates of candidate sour (14.7%) and bitter (1.8%) receptors were far higher in humans than those of sweet (0.02%), salty (0.05%) and umami (0.17%) receptors compared with other carnivorous mammals, although not all of the taste receptors were identified. Many LoF variants are population-specific, some of which arose even after population differentiation, not before divergence of the modern and archaic human. I conclude that modern humans might have been losing some sour and bitter receptor genes because of high-frequency LoF variants.

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