T1R3

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Button receptor type 1 member 3
other names

Sweet taste receptor T1R3, TS1R3, TAS1R3

Properties of human protein
Mass / length primary structure 832 amino acids
Precursor 852 amino acids, 93,386 Da
Identifier
External IDs
Orthologue (human)
Entrez 83756
Ensemble ENSG00000169962
UniProt Q7RTX0
Refseq (mRNA) NM_152228.2
Refseq (protein) NP_689414.1
PubMed search 83756

Key receptor type 1 member 3 (T1R3) is a protein from the group of G-protein-coupled receptors in the human and a part of both the receptor for sweet taste as well as a part of the receptor for the Umami flavored.

properties

T1R3 forms a heterodimer with T1R2 , whereupon it binds sugar , sugar substitutes and sweeteners and is activated by them. Only the heterodimer of T1R2 and T1R3 is the functional receptor for sweet taste. T1R3 is eight-fold N - glycosylated . T1R3 has one large extracellular protein domain and seven transmembrane domains . Originally it was erroneously assumed that glucose and aspartame do not activate T1R2 and T1R3 and therefore further receptors for the sweet taste must be present, but this was later refuted for the human receptor, whereas in rats there is no activation by aspartame and only a slight activation by glucose. After activation of T1R3, Gαo and Gαi subunits of G proteins are activated, especially the Gα subunit of gustducin . This presumably inhibits adenylyl cyclases . Further signal transduction takes place via the phospholipase C PLCβ2 and the ion channel TRPM5 , as is the case with the receptor for bitter taste (receptor family T2R ). As a result of the activation of the phospholipase PLC-β2, PIP 2 and diacylglycerol are formed. This is followed by activation of the IP3 receptor and an increase in Ca 2+ in the cytosol , whereupon the ion channel TRPM5 is activated.

In the taste buds with T1R2 and T1R3, no receptors for the bitter taste are expressed . The receptor from T1R2 and T1R3 is also formed in other tissues and is probably involved in the regulation of energy metabolism there . Amiloride inhibits human sweet taste by binding to T1R2, while lactisol inhibits human sweet and umami taste by binding to T1R3.

As a heterodimer with T1R1 , T1R3 forms the receptor for umami taste and binds the amino acid glutamate . The binding of glutamates is enhanced by 5'- ribonucleotides , such as inosine monophosphate (IMP) and guanosine monophosphate (GMP), while without glutamate they do not activate the receptor. Methional is an allosteric modulator of the taste receptor made up of the two proteins T1R1 and T1R3. On human receptors, its potency is exceeded by 3- (methylthio) butanal.

Individual evidence

  1. ↑ a b TAS1R3 - Taste receptor type 1 member 3 precursor - Homo sapiens (Human) - TAS1R3 gene & protein. In: uniprot.org. March 29, 2005, accessed August 26, 2018 .
  2. ↑ a b c G. Nelson, MA Hoon, J. Chandrashekar, Y. Zhang, NJ Ryba, CS Zuker: Mammalian sweet taste receptors. In: Cell . Volume 106, Number 3, August 2001, pp. 381-390, PMID 11509186 .
  3. ↑ a b c E. Sainz, MM Cavenagh, ND Lopez-Jimenez, JC Gutierrez, JF Battey, JK Northup, SL Sullivan: The G-protein coupling properties of the human sweet and amino acid taste receptors. In: Developmental neurobiology. Volume 67, number 7, June 2007, pp. 948-959, doi : 10.1002 / dneu.20403 , PMID 17506496 .
  4. ↑ a b c X. Li, L. Staszewski, H. Xu, K. Durick, M. Zoller, E. Adler: Human receptors for sweet and umami taste. In: Proceedings of the National Academy of Sciences . Volume 99, number 7, April 2002, pp. 4692-4696, doi : 10.1073 / pnas.072090199 , PMID 11917125 , PMC 123709 (free full text).
  5. ↑ T. Abaffy, KR Trubey, N. Chaudhari: Adenylyl cyclase expression and modulation of cAMP in rat taste cells. In: American Journal of Physiology - Cell Physiology. Volume 284, Number 6, June 2003, pp. C1420-C1428, doi : 10.1152 / ajpcell.00556.2002 , PMID 12606315 .
  6. ↑ Y. Zhang, MA Hoon, J. Chandrashekar, KL Mueller, B. Cook, D. Wu, CS Zuker, NJ Ryba: Coding of sweet, bitter, and umami tastes: different receptor cells sharing similar signaling pathways. In: Cell . Volume 112, Number 3, February 2003, pp. 293-301, PMID 12581520 .
  7. ↑ a b c C. D. Dotson, S. Vigues, NI Steinle, SD Munger: T1R and T2R receptors: the modulation of incretin hormones and potential targets for the treatment of type 2 diabetes mellitus. In: Current opinion in investigational drugs. Volume 11, Number 4, April 2010, pp. 447-454, PMID 20336593 , PMC 4535793 (free full text).
  8. ↑ A. Laffitte, F. Neiers, L. Briand: Functional roles of the sweet taste receptor in oral and extra-oral tissues. In: Current opinion in clinical nutrition and metabolic care. Volume 17, number 4, July 2014, pp. 379-385, doi : 10.1097 / MCO.0000000000000058 , PMID 24763065 , PMC 4059820 (free full text).
  9. ↑ M. Zhao, XQ Xu, XY Meng, B. Liu: The Heptahelical Domain of the Sweet Taste Receptor T1R2 Is a New Allosteric Binding Site for the Sweet Taste Modulator Amiloride That Modulates Sweet Taste in a Species-Dependent Manner. In: Journal of molecular neuroscience: MN. [Electronic publication before printing] August 2018, doi : 10.1007 / s12031-018-1156-5 , PMID 30120716 .
  10. ↑ H. Xu, L. Staszewski, H. Tang, E. Adler, M. Zoller, X. Li: Different functional roles of T1R subunits in the heteromeric taste receptors. In: Proceedings of the National Academy of Sciences . Volume 101, number 39, September 2004, pp. 14258-14263, doi : 10.1073 / pnas.0404384101 , PMID 15353592 , PMC 521102 (free full text).
  11. ↑ G. Nelson, J. Chandrashekar, MA Hoon, L. Feng, G. Zhao, NJ Ryba, CS Zuker: An amino-acid taste receptor. In: Nature . Volume 416, number 6877, March 2002, pp. 199-202, doi : 10.1038 / nature726 , PMID 11894099 .
  12. ↑ Toda Y et al .: Positive / Negative Allosteric Modulation Switching in an Umami Taste Receptor (T1R1 / T1R3) by a Natural Flavor Compound, Methional . In: Sci Rep . 8, No. 1, August 2018, p. 11796. doi : 10.1038 / s41598-018-30315-x . PMID 30087430 . PMC 6081381 (free full text).