Taste information derived from T1R-expressing taste cells in mice

2016 ◽  
Vol 473 (5) ◽  
pp. 525-536 ◽  
Author(s):  
Ryusuke Yoshida ◽  
Yuzo Ninomiya
Keyword(s):  
Taste Receptor ◽  
G Protein Coupled Receptors ◽  
Taste Bud ◽  
Taste System ◽  
Umami Taste ◽  
Behavioural Avoidance ◽  
Taste Cells ◽  
G Protein Coupled ◽  
Taste Bud Cells

The taste system of animals is used to detect valuable nutrients and harmful compounds in foods. In humans and mice, sweet, bitter, salty, sour and umami tastes are considered the five basic taste qualities. Sweet and umami tastes are mediated by G-protein-coupled receptors, belonging to the T1R (taste receptor type 1) family. This family consists of three members (T1R1, T1R2 and T1R3). They function as sweet or umami taste receptors by forming heterodimeric complexes, T1R1+T1R3 (umami) or T1R2+T1R3 (sweet). Receptors for each of the basic tastes are thought to be expressed exclusively in taste bud cells. Sweet (T1R2+T1R3-expressing) taste cells were thought to be segregated from umami (T1R1+T1R3-expressing) taste cells in taste buds. However, recent studies have revealed that a significant portion of taste cells in mice expressed all T1R subunits and responded to both sweet and umami compounds. This suggests that sweet and umami taste cells may not be segregated. Mice are able to discriminate between sweet and umami tastes, and both tastes contribute to behavioural preferences for sweet or umami compounds. There is growing evidence that T1R3 is also involved in behavioural avoidance of calcium tastes in mice, which implies that there may be a further population of T1R-expressing taste cells that mediate aversion to calcium taste. Therefore the simple view of detection and segregation of sweet and umami tastes by T1R-expressing taste cells, in mice, is now open to re-examination.

Inhibition of signal termination-related kinases by membrane-permeant bitter and sweet tastants: potential role in taste signal termination

2005 ◽  
Vol 289 (2) ◽  
pp. C483-C492 ◽  
Author(s):  
Meirav Zubare-Samuelov ◽  
Merav E. Shaul ◽  
Irena Peri ◽  
Alexander Aliluiko ◽  
Oren Tirosh ◽  
...  
Keyword(s):  
Potential Role ◽  
Taste Bud ◽  
Significant Delay ◽  
Chemical Structures ◽  
Taste Cells ◽  
G Protein Coupled ◽  
New Hypothesis ◽  
Taste Bud Cells

Sweet and bitter taste sensations are believed to be initiated by the tastant-stimulated T1R and T2R G protein-coupled receptor (GPCR) subfamilies, respectively, which occur in taste cells. Although such tastants, with their significantly diverse chemical structures (e.g., sugar and nonsugar sweeteners), may share the same or similar T1Rs, some nonsugar sweeteners and many bitter tastants are amphipathic and produce a significant delay in taste termination (lingering aftertaste). We report that such tastants may permeate rat taste bud cells rapidly in vivo and inhibit known signal termination-related kinases in vitro, such as GPCR kinase (GRK)2, GRK5, and PKA. GRK5 and perhaps GRK2 and GRK6 are present in taste cells. A new hypothesis is proposed in which membrane-permeant tastants not only interact with taste GPCRs but also interact intracellularly with the receptors' downstream shutoff components to inhibit signal termination.

scholarly journals The umami receptor T1R1–T1R3 heterodimer is rarely formed in chickens

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yuta Yoshida ◽  
Fuminori Kawabata ◽  
Shotaro Nishimura ◽  
Shoji Tabata
Keyword(s):  
Molecular Mechanisms ◽  
Expression Patterns ◽  
Taste Receptor ◽  
Taste Bud ◽  
Receptor Type ◽  
Sensory Cells ◽  
Feeding Behaviors ◽  
Taste System ◽  
Second Messenger Signaling ◽  
Taste Bud Cells

AbstractThe characterization of molecular mechanisms underlying the taste-sensing system of chickens will add to our understanding of their feeding behaviors in poultry farming. In the mammalian taste system, the heterodimer of taste receptor type 1 members 1/3 (T1R1/T1R3) functions as an umami (amino acid) taste receptor. Here, we analyzed the expression patterns of T1R1 and T1R3 in the taste cells of chickens, labeled by the molecular markers for chicken taste buds (vimentin and α-gustducin). We observed that α-gustducin was expressed in some of the chicken T1R3-positive taste bud cells but rarely expressed in the T1R1-positive and T2R7-positive taste bud cells. These results raise the possibility that there is another second messenger signaling system in chicken taste sensory cells. We also observed that T1R3 and α-gustducin were expressed mostly in the vimentin-positive taste bud cells, whereas T1R1 and bitter taste receptor (i.e., taste receptor type 2 member 7, T2R7) were expressed largely in the vimentin-negative taste bud cells in chickens. In addition, we observed that T1R1 and T1R3 were co-expressed in about 5% of chickens' taste bud cells, which express T1R1 or T1R3. These results suggest that the heterodimer of T1R1 and T1R3 is rarely formed in chickens’ taste bud cells, and they provide comparative insights into the expressional regulation of taste receptors in the taste bud cells of vertebrates.

scholarly journals Bitter taste receptor T2R7 and umami taste receptor subunit T1R1 are expressed highly in Vimentin-negative taste bud cells in chickens

2019 ◽  
Vol 511 (2) ◽  
pp. 280-286 ◽  
Author(s):  
Yuta Yoshida ◽  
Zhonghou Wang ◽  
Kayvan F. Tehrani ◽  
Emily G. Pendleton ◽  
Ryota Tanaka ◽  
...  
Keyword(s):  
Bitter Taste ◽  
Taste Receptor ◽  
Taste Bud ◽  
Receptor Subunit ◽  
Bitter Taste Receptor ◽  
Umami Taste ◽  
Taste Bud Cells

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 Activating autoantibodies against G protein-coupled receptors in narcolepsy type 1

2021 ◽  
Vol 77 ◽  
pp. 82-87
Author(s):  
Maija Orjatsalo ◽  
Eemil Partinen ◽  
Gerd Wallukat ◽  
Anniina Alakuijala ◽  
Markku Partinen
Keyword(s):  
G Protein ◽  
G Protein Coupled Receptors ◽  
Activating Autoantibodies ◽  
G Protein Coupled

scholarly journals Beyond the Flavour: The Potential Druggability of Chemosensory G Protein-Coupled Receptors

2019 ◽  
Vol 20 (6) ◽  
pp. 1402 ◽  
Author(s):  
Antonella Di Pizio ◽  
Maik Behrens ◽  
Dietmar Krautwurst
Keyword(s):  
G Protein ◽  
Drug Targets ◽  
Current Knowledge ◽  
Chemical Space ◽  
G Protein Coupled Receptors ◽  
The Body ◽  
Odorant Receptors ◽  
Taste Receptors ◽  
Umami Taste ◽  
G Protein Coupled

G protein-coupled receptors (GPCRs) belong to the largest class of drug targets. Approximately half of the members of the human GPCR superfamily are chemosensory receptors, including odorant receptors (ORs), trace amine-associated receptors (TAARs), bitter taste receptors (TAS2Rs), sweet and umami taste receptors (TAS1Rs). Interestingly, these chemosensory GPCRs (csGPCRs) are expressed in several tissues of the body where they are supposed to play a role in biological functions other than chemosensation. Despite their abundance and physiological/pathological relevance, the druggability of csGPCRs has been suggested but not fully characterized. Here, we aim to explore the potential of targeting csGPCRs to treat diseases by reviewing the current knowledge of csGPCRs expressed throughout the body and by analysing the chemical space and the drug-likeness of flavour molecules.

scholarly journals Minireview: Nutrient Sensing by G Protein-Coupled Receptors

2013 ◽  
Vol 27 (8) ◽  
pp. 1188-1197 ◽  
Author(s):  
Eric M. Wauson ◽  
Andrés Lorente-Rodríguez ◽  
Melanie H. Cobb
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
G Protein ◽  
Taste Receptor ◽  
Sweet Taste ◽  
Nutrient Sensing ◽  
G Protein Coupled Receptors ◽  
Amino Acid Availability ◽  
Class C ◽  
G Protein Coupled

G protein-coupled receptors (GPCRs) are membrane proteins that recognize molecules in the extracellular milieu and transmit signals inside cells to regulate their behaviors. Ligands for many GPCRs are hormones or neurotransmitters that direct coordinated, stereotyped adaptive responses. Ligands for other GPCRs provide information to cells about the extracellular environment. Such information facilitates context-specific decision making that may be cell autonomous. Among ligands that are important for cellular decisions are amino acids, required for continued protein synthesis, as metabolic starting materials and energy sources. Amino acids are detected by a number of class C GPCRs. One cluster of amino acid-sensing class C GPCRs includes umami and sweet taste receptors, GPRC6A, and the calcium-sensing receptor. We have recently found that the umami taste receptor heterodimer T1R1/T1R3 is a sensor of amino acid availability that regulates the activity of the mammalian target of rapamycin. This review focuses on an array of findings on sensing amino acids and sweet molecules outside of neurons by this cluster of class C GPCRs and some of the physiologic processes regulated by them.

Adrenomedullin: receptor and signal transduction

2002 ◽  
Vol 30 (4) ◽  
pp. 432-437 ◽  
Author(s):  
D. M. Smith ◽  
H. A. Coppock ◽  
D. J. Withers ◽  
A. A. Owji ◽  
D. L. Hay ◽  
...  
Keyword(s):  
G Protein ◽  
Vascular Tissue ◽  
G Protein Coupled Receptors ◽  
Type Ii ◽  
Calcitonin Gene ◽  
Adrenomedullin Receptor ◽  
Receptor Activity Modifying Proteins ◽  
G Protein Coupled ◽  
Chemical Cross Linking

Adrenomedullin is a vascular tissue peptide and a member of the calcitonin family of peptides, which includes calcitonin, calcitonin-gene-related peptide (CGRP) and amylin. Its many biological actions are mediated via CGRP type 1 (CGRP1) receptors and by specific adrenomedullin receptors. Although the pharmacology of these receptors is distinct, they are both represented in molecular terms by the type II family G-protein-coupled receptor, calcitonin-receptor-like receptor (CRLR). The specificity here is defined by co-expression of receptor-activity-modifying proteins (RAMPs). CGRP1 receptors are represented by CRLR and RAMP1, and specific adrenomedullin receptors by CRLR and RAMP2 or 3. Here we discuss how CRLR/RAMP2 relates to adrenomedullin binding, pharmacology and pathophysiology, and how chemical cross-linking of receptor-ligand complexes in tissue relates to that in CRLR/RAMP2-expressing cells. CRLR, like other type II family G-protein-coupled receptors, signals via Gs and adenylate cyclase activation. We demonstrated that adrenomedullin signalling in cell lines expressing specific adrenomedullin receptors followed this expected pattern.

scholarly journals A subset of broadly responsive Type III taste cells contribute to the detection of bitter, sweet and umami stimuli

2019 ◽  
Author(s):  
Debarghya Dutta Banik ◽  
Eric D. Benfey ◽  
Laura E. Martin ◽  
Kristen E. Kay ◽  
Gregory C. Loney ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Taste Receptor ◽  
Live Cell ◽  
Type I ◽  
Type Ii Cells ◽  
Type Ii ◽  
Type Iii ◽  
Umami Taste ◽  
Taste Cells ◽  
Multiple Signaling

ABSTRACTTaste receptor cells use multiple signaling pathways to detect chemicals in potential food items. These cells are functionally grouped into different types: Type I cells act as support cells and have glial-like properties; Type II cells detect bitter, sweet, and umami taste stimuli; and Type III cells detect sour and salty stimuli. We have identified a new population of taste cells that are broadly tuned to multiple taste stimuli including bitter, sweet, sour and umami. The goal of this study was to characterize these broadly responsive (BR) taste cells. We used an IP3R3-KO mouse (does not release calcium (Ca2+) from Type II cells when stimulated with bitter, sweet or umami stimuli) to characterize the BR cells without any potentially confounding input from Type II cells. Using live cell Ca2+ imaging in isolated taste cells from the IP3R3-KO mouse, we found that BR cells are a subset of Type III cells that respond to sour stimuli but also use a PLCβ3 signaling pathway to respond to bitter, sweet and umami stimuli. Unlike Type II cells, individual BR cells are broadly tuned and respond to multiple stimuli across different taste modalities. Live cell imaging in a PLCβ3-KO mouse confirmed that BR cells use a PLCβ3 signaling pathway to generate Ca2+ signals to bitter, sweet and umami stimuli. Analysis of c-Fos activity in the nucleus of the solitary tract (NTS) and short term behavioral assays revealed that BR cells make significant contributions to taste.

scholarly journals Sweet Taste Is Complex: Signaling Cascades and Circuits Involved in Sweet Sensation

2021 ◽  
Vol 15 ◽  
Author(s):  
Elena von Molitor ◽  
Katja Riedel ◽  
Michael Krohn ◽  
Mathias Hafner ◽  
Rüdiger Rudolf ◽  
...  
Keyword(s):  
Alternative Pathway ◽  
Taste Receptor ◽  
Physiological Role ◽  
Primary Source ◽  
Sweet Taste ◽  
Receptor Expression ◽  
Taste Bud ◽  
Sweet Taste Receptor ◽  
The Brain ◽  
Taste Bud Cells

Sweetness is the preferred taste of humans and many animals, likely because sugars are a primary source of energy. In many mammals, sweet compounds are sensed in the tongue by the gustatory organ, the taste buds. Here, a group of taste bud cells expresses a canonical sweet taste receptor, whose activation induces Ca2+ rise, cell depolarization and ATP release to communicate with afferent gustatory nerves. The discovery of the sweet taste receptor, 20 years ago, was a milestone in the understanding of sweet signal transduction and is described here from a historical perspective. Our review briefly summarizes the major findings of the canonical sweet taste pathway, and then focuses on molecular details, about the related downstream signaling, that are still elusive or have been neglected. In this context, we discuss evidence supporting the existence of an alternative pathway, independent of the sweet taste receptor, to sense sugars and its proposed role in glucose homeostasis. Further, given that sweet taste receptor expression has been reported in many other organs, the physiological role of these extraoral receptors is addressed. Finally, and along these lines, we expand on the multiple direct and indirect effects of sugars on the brain. In summary, the review tries to stimulate a comprehensive understanding of how sweet compounds signal to the brain upon taste bud cells activation, and how this gustatory process is integrated with gastro-intestinal sugar sensing to create a hedonic and metabolic representation of sugars, which finally drives our behavior. Understanding of this is indeed a crucial step in developing new strategies to prevent obesity and associated diseases.

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