Gustducin is a taste-cell-specific G protein closely related to the transducins

  title={Gustducin is a taste-cell-specific G protein closely related to the transducins},
  author={S K Mclaughlin and Robert F. Margolskee},
A novel G protein α-subunit (α-gustducin) has been identified and cloned from taste tissue, α-Gustducin messenger RNA is expressed in taste buds of all taste papillae (circumvallate, foliate and fungiform); it is not expressed in non-sensory portions of the tongue, nor is it expressed in the other tissues examined, α-Gustducin most closely resembles the transducins (the rod and cone photoreceptor G proteins), suggesting that gustducin's role in taste transduction is analogous to that of… 
Gustducin and transducin: a tale of two G proteins.
The primary sequence of alpha gustducin shows similarities to the transducins in the receptor interaction domain and the phosphodiesterase activation site, which suggest that gust Ducin and transducin regulate taste cell phosphodiesters, probably in bitter taste transduction.
Gustducin and its Role in Taste
A proposed mechanism for α-gustducin involves coupling specific cell-surface receptors with a cyclic nucleotide phosphodiesterase which would open a cyclIC nucleotide-suppressible cation channel leading to influx of calcium, and ultimately leading to release of neurotransmitter.
Differential Expression of α-Gustducin in Taste Bud Populations of the Rat and Hamster
The hypothesis that α-gustducin is involved in the transduction of both sweet- and bitter-tasting stimuli by mammalian taste receptor cells is supported.
Umami Taste Responses Are Mediated by α-Transducin and α-Gustducin
It is found that αt-rod played no role in taste responses to the salty, bitter, and sweet compounds tested or to IMP but was involved in the umami taste of MSG and MPG.
Differential expression of alpha-gustducin in taste bud populations of the rat and hamster.
The hypothesis that alpha-gustducin is involved in the transduction of both sweet- and bitter-tasting stimuli by mammalian taste receptor cells is supported.
Functional Interaction between T2R Taste Receptors and G-Protein α Subunits Expressed in Taste Receptor Cells
A heterologous expression system is used to determine a specific domain of gustducin necessary for T2R coupling and expresses G16 protein chimeras with the corresponding domain from other Gαi proteins, cone-transducin (Gαt2, G αi2, and Gαz), which could be useful tools to analyze the functions of many orphan G-protein-coupled taste receptors.
Molecular Functional Interaction between T 2 R Taste Receptors and G-Protein Subunits Expressed in Taste Receptor Cells
The present G 16-based chimeras could be useful tools to analyze the functions of many orphan G-protein-coupled taste receptors.
α‐Gustducin expression in the vomeronasal organ of the mouse
Results show for the first time that α gustducin is expressed in chemosensory tissue outside the alimentary tract, suggesting that common transduction mechanisms could be shared by apparently unrelated chemos Sensory tissues.


Taste transduction: a diversity of mechanisms
Transduction in taste receptor cells requires cAMP-dependent protein kinase
It is shown that cAMP causes a substantial depolarization in these cells, which differs from that of olfactory3 and photoreceptor cells4,5, where cyclic nucleotides control unspecific channels by binding to them rather than by inducing their phosphorylation.
Golf: an olfactory neuron specific-G protein involved in odorant signal transduction.
Evidence is presented suggesting that this G protein, termed Golf, mediates olfaction, and the expression of Golf alpha in S49 cyc- kin- cells, a line deficient in endogenous stimulatory G proteins, demonstrates its capacity to stimulate adenylate cyclase in a heterologous system.
The cell biology of vertebrate taste receptors.
  • S. Roper
  • Biology
    Annual review of neuroscience
  • 1989
The model of chemosensory processing in the taste bud presented here can now be explored in great detail and indicates a potential for intriguing peripheral integrative mechanisms, including cross-talk between taste cells, summation of chemoreceptor responses by interneurons, and centrifugal control of taste buds via efferent input from the CNS.
A bitter substance induces a rise in intracellular calcium in a subpopulation of rat taste cells.
The transduction of bitter taste may occur via a receptor-second messenger mechanism leading to neurotransmitter release and may not involve depolarization-mediated calcium entry.
Salt taste transduction occurs through an amiloride-sensitive sodium transport pathway.
The data show that amiloride is a specific blocker of the chorda tympani response to sodium chloride, but not to potassium chloride, that the sodium and potassium gustatory systems are largely independent at the peripheral level, and that the classical ion taste "receptor" is actually a specific transport pathway permitting the cation to enter the taste-bud cell and thereby to spread depolarizing current.
Sweet tastants stimulate adenylate cyclase coupled to GTP-binding protein in rat tongue membranes.
Sucrose and other saccharides, which produce an appealing taste in rats, were found to significantly stimulate the activity of adenylate cyclase in membranes derived from the anterior-dorsal region of rat tongue, consistent with a sweet-taste transduction mechanism involving specific receptors, a guanine-nucleotide-binding protein and the cyclic AMP-generating enzyme.
Cyclic nucleotides may mediate taste transduction
The results suggest that a cyclic nucleotide enzymatic cascade, modulated by calcium ions, may mediate the potassium permeability that controls taste, in a way analogous to visual and olfactory transduction.
Phosphodiesterase in Tongue Epithelium: Activation by Bitter Taste Stimuli
The phosphodiesterase activity in tongue epithelium was studied to determine whether unusually high levels of this enzyme might also be associated with taste receptors, and to explore the possibility that taste stimuli might affect phosphodiesters activity, thereby altering the intracellular cAMP concentrations.
Identification of specific transducin alpha subunits in retinal rod and cone photoreceptors.
Bovine rod and cone cells each express structurally related yet significantly different forms of transducin, and localization of this polypeptide in bovine retina by indirect immunofluorescence demonstrates that it is expressed only in cone outer segments.