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Entry
map04742                    Pathway                                

Name
Taste transduction
Description
All taste pathways are proposed to converge on common elements that mediate a rise in intracellular Ca2+ followed by neurotransmitter release. Na+ salt depolarizes taste cells by passive influx of Na+ through the amiloride-sensitive Na+ channel (ENaC). Acids depolarize taste cells by a variety of mechanisms, including influx of protons (H+) through ENaC and a proton-gated cation channel (MDEG). Two putative umami receptors have been identified: a truncated variant of the metabotropic glutamate receptor mGluR4 and the heterodimer, T1R1 + T1R3. Umami receptors are coupled to a signaling pathway involving activation of PLCbeta2, production of IP3 and diacylglycerol, release of Ca2+ from intracellular stores and activation of a transient receptor potential channel, TRPM5. Bitter compounds, such as denatonium and PROP, activate particular T2R/TRB isoforms, which activate gustducin heterotrimers. Activated alpha-gustducin stimulates PDE to hydrolyze cAMP, whereas betagamma subunits activate PLCbeta2 to generate IP3, which leads to release of Ca2+ from internal stores. Artificial sweeteners activate GPCRs (T1R heterodimers) apparently linked via PLC to IP3 production and release of Ca2+ from intracellular stores. Sugars apparently activate GPCRs linked via AC to cAMP production which, in turn, may inhibit basolateral K+ channels through phosphorylation by cAMP-activated protein kinase A (PKA).
Class
Organismal Systems; Sensory system
BRITE hierarchy
Pathway map
Taste transduction
map04742

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Reference
  Authors
Zhang Y, Hoon MA, Chandrashekar J, Mueller KL, Cook B, Wu D, Zuker CS, Ryba NJ.
  Title
Coding of sweet, bitter, and umami tastes: different receptor cells sharing similar signaling pathways.
  Journal
Cell 112:293-301 (2003)
Reference
  Authors
Bigiani A, Ghiaroni V, Fieni F.
  Title
Channels as taste receptors in vertebrates.
  Journal
Prog Biophys Mol Biol 83:193-225 (2003)
Reference
  Authors
Kinnamon SC, Lin W, Ogura T, Ruiz C, Delay E.
  Title
Downstream signaling effectors for umami taste.
  Journal
Chem Senses 30 Suppl 1:i31-i32 (2005)
Reference
  Authors
Meyerhof W.
  Title
Elucidation of mammalian bitter taste.
  Journal
Rev Physiol Biochem Pharmacol 154:37-72 (2005)
Reference
  Authors
Margolskee RF.
  Title
Molecular mechanisms of bitter and sweet taste transduction.
  Journal
J Biol Chem 277:1-4 (2002)
Reference
  Authors
Gilbertson TA, Damak S, Margolskee RF.
  Title
The molecular physiology of taste transduction.
  Journal
Curr Opin Neurobiol 10:519-27 (2000)
Reference
  Authors
DeSimone JA, Lyall V, Heck GL, Feldman GM.
  Title
Acid detection by taste receptor cells.
  Journal
Respir Physiol 129:231-45 (2001)
Reference
  Authors
Lin W, Ogura T, Kinnamon SC.
  Title
Acid-activated cation currents in rat vallate taste receptor cells.
  Journal
J Neurophysiol 88:133-41 (2002)
Reference
  Authors
Feldman GM, Mogyorosi A, Heck GL, DeSimone JA, Santos CR, Clary RA, Lyall V.
  Title
Salt-evoked lingual surface potential in humans.
  Journal
J Neurophysiol 90:2060-4 (2003)
Reference
PMID:8794107
  Authors
Kinnamon SC, Margolskee RF.
  Title
Mechanisms of taste transduction.
  Journal
Curr Opin Neurobiol 6:506-13 (1996)
Reference
  Authors
Perez CA, Huang L, Rong M, Kozak JA, Preuss AK, Zhang H, Max M, Margolskee RF.
  Title
A transient receptor potential channel expressed in taste receptor cells.
  Journal
Nat Neurosci 5:1169-76 (2002)
Reference
  Authors
Kim MR, Kusakabe Y, Miura H, Shindo Y, Ninomiya Y, Hino A.
  Title
Regional expression patterns of taste receptors and gustducin in the mouse tongue.
  Journal
Biochem Biophys Res Commun 312:500-6 (2003)
Reference
PMID:9146906
  Authors
Uchida Y, Sato T.
  Title
Changes in outward K+ currents in response to two types of sweeteners in sweet taste transduction of gerbil taste cells.
  Journal
Chem Senses 22:163-9 (1997)
Reference
  Authors
Wettschureck N, Offermanns S.
  Title
Mammalian G proteins and their cell type specific functions.
  Journal
Physiol Rev 85:1159-204 (2005)
Reference
  Authors
Scott K.
  Title
Taste recognition: food for thought.
  Journal
Neuron 48:455-64 (2005)
Reference
  Authors
Damak S, Rong M, Yasumatsu K, Kokrashvili Z, Perez CA, Shigemura N, Yoshida R, Mosinger B Jr, Glendinning JI, Ninomiya Y, Margolskee RF.
  Title
Trpm5 null mice respond to bitter, sweet, and umami compounds.
  Journal
Chem Senses 31:253-64 (2006)
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