TCDB is operated by the Saier Lab Bioinformatics Group
TCIDNameDomainKingdom/PhylumProtein(s)
1.A.69.1.1









Heteromeric odorant receptor, OR (Sato et al., 2008). OR22a senses fruit-derived esters. These olfactory receptors may have 3-d structures resembling animal rhodopsins, human citronellic terpenoid receptors, OR1A1 and OA1A2 and the mouse eugenol receptor, OR-EG (Ramdya and Benton, 2010). Molecular modelling of oligomeric states of DmOR83b has been reported (Harini and Sowdhamini, 2012).  Recombinant receptor together with the co-receptor, Orco, has been overproduced, purified and reconstituted in a lipid bilayer (Carraher et al. 2013).  Orco (Or83b) forms a dimer that is fully functional for Ca2+ transport, is regulated by calmodulin and interacts normally with Or22a.  The native Orco is therefore probably a dimer (Mukunda et al. 2014).

Eukaryota
Metazoa
Heterometic odorant receptor (OR) of Drosophila melanogaster:
OR83b (Q9VNB5)
OR46a (P81919)
OR43b (P81918)
OR22a (P81909)
OR22b (P81910)
1.A.69.1.2









Odorant receptor, OR2 (Carraher et al., 2012).

Eukaryota
Metazoa
OR2 of Anopheles gambiae (Q8WTE6)
1.A.69.1.3









Odorant receptor 56a.  Mediates aversive responses to harmful microbial (bacterial and fungal) products such as geosmin (trans-1,10-dimetnyl-trans-9-decalol). (Stensmyr et al. 2012).

Eukaryota
Metazoa
OR56a of Drosophila melanogaster
1.A.69.1.4









Ordorant receptor 67b of 421 aas and 8 TMSs  (Identical to Or67b of D. melanogaster)

Eukaryota
Metazoa
Or67b of Drosophila simulans
1.A.69.1.5









Odorant receptor 10b of 406 aas and 7 TMSs

Eukaryota
Metazoa
Or10b of Drosophila melanogaster
1.A.69.2.1









The insect heteromeric CO2 receptor: GR21a (Olfactory receptor 21a; 454 aas) GR63a (Olfactory receptor 63a; 512 aas) are coexpressed in antennal neurons of insects and together comprise the peripheral sensory receptor for CO2 (Ramdya and Benton, 2010). These proteins are members of the 7Tm-7 superfamily of putative 7TMS proteins.

Eukaryota
Metazoa
The gustatory receptor for CO2, GR21a/GRG3a of Drosophila melanogaster
GR21a (Q9VPT1)
GR63a (Q9VZL7)
1.A.69.2.2









Uncharacterized protein of 382 aas and 9 TMSs.

Eukaryota
Metazoa
UP of Frankliniella occidentalis (western flower thrips)
1.A.69.2.3









Gustatory receptor for sugar taste 64e-like protein, GR64e, of 486 aas and 8 TMSs.

Eukaryota
Metazoa
GR64e protein of Atta cephalotes (Leafcutter ant)
1.A.69.2.4









Uncharacterized protein of 416 aas and 7 TMSs.

Eukaryota
Metazoa
UP of Aphis gossypii (cotton aphid)
1.A.69.2.5









Uncharacterized protein of 425 aas and 7 TMSs.

Eukaryota
Metazoa
UP of Amphibalanus amphitrite
1.A.69.3.1









Fructose-regulated Ca2+/cation channel, Gustatory (fructose) receptor-9, Gr9 (Sato et al., 2011). Gr9 is widely expressed in the central nervous system (CNS), as well as oral sensory organs and is involved in the promotion of feeding behaviors (Mang et al. 2016).

Eukaryota
Metazoa
GR-9 of Bombyx mori (B3GTD7)
1.A.69.3.2









Gustatory receptor 43a isoform A.  Functions as a narrowly tuned fructose receptor in taste neurons (Miyamoto et al. 2012), being both necessary and sufficient to sense hemolymph fructose.

Eukaryota
Metazoa
GR43a of Drosophila melanogaster (Q9V4K2)
1.A.69.3.3









Gustatory receptor 28b isoform D of 470 aas and 8 TMSs. It mediates acceptance or avoidance behavior, depending on its substrates. Its atypical expression suggests additional nongustatory roles in the nervous system and tissues involved in proprioception (warmth receptor), hygroreception, and other sensory modalities. It is also possible that it has chemosensory roles in the detection of internal ligands (Thorne and Amrein 2008). Saponins function in natural self-defense for plants to deter various insects due to their unpleasant taste and toxicity. Sang et al. 2019 provided evidence that saponin from Quillaja saponaria functions as an antifeedant as well as an insecticide to ward off insects in both the larval and the adult stages.

Eukaryota
Metazoa
GR28b of Drosophila melanogaster (Q9VM08)
1.A.69.3.4









Gustatory receptor 2a isoform B

Eukaryota
Metazoa
GR2a of Drosophila melanogaster (Q9W594)
1.A.69.3.5









High energy light unresponsive protein 1, Lite1; chemoreceptor GUR-2 of 439 aas and 8 TMSs. It is a photoreceptor for short wavelength (UV) light that mediates UV-light-induced avoidance behavior (Edwards et al. 2008, Liu et al. 2010, Gong et al. 2016). It directly senses and absorbs both UV-A and UV-B light with very high efficiency (Gong et al. 2016). Absorption of UV-B but not UV-A light shows resistance to photobleaching. In contrast to other photoreceptors, it does not use a prosthetic chromophore to capture photons and only depends on its protein conformation. It may play a role in response to white light exposure (De Magalhaes Filho et al. 2018) as well as color detection (Ghosh et al. 2021).

Eukaryota
Metazoa
GUR-2 of Caenorhabditis elegans
1.A.69.3.6









Gustatory receptor, GPRGR53, of 430 aas and 7 TMSs. It mediates acceptance or avoidance behavior, depending on its substrates.

Eukaryota
Metazoa
GPRGR53 of Anopheles gambiae (African malaria mosquito)
1.A.69.3.7









Putative gustatory receptor 98b of 402 aas and 7 TMSs.

Eukaryota
Metazoa
GR98b of Bactrocera latifrons
1.A.69.3.8









Gustatory receptor family protein 3, Gur-3, of 447 aas and 8 - 9 TMSs. It is a chemoreceptor involved in light-induced avoidance behavior (Bhatla and Horvitz 2015) and probably acts as a molecular sensor in I2 pharyngeal neurons, required for the inhibition of feeding in response to light and hydrogen peroxide. It may be involved in circadian rhythms, probably by acting as a light sensor (Goya et al. 2016). Although it acts with Lite-1 in color detection, it does not act as a photoreceptor (Ghosh et al. 2021).

Eukaryota
Opisthokonta
Gur-3 of Caenorhabditis elegans
1.A.69.4.1









The pheromone receptor, Or-1 (Nakagawa et al., 2012)

Eukaryota
Metazoa
Or-1 of Bombyx mori (Q5WA61)
1.A.69.4.2









Sex pheromone receptor of 416 aas and 7 TMSs (Miura et al. 2010).

Eukaryota
Metazoa
pheromone receptor of Ostrinia nubilalis (European corn borer) (Pyralis nubilalis)
1.A.69.4.3









Odorant receptor 3, Or3 of 410 aas and 7 TMSs.

Eukaryota
Metazoa
Or3 of Epiphyas postvittana (Light brown apple moth)
1.A.69.4.4









Odorant (pheromone) receptor, OR-3, BmOR3, Or-3, PR-3, of 439 aas and 7 TMSs in a 2 + 1 + 2 + 2 TMS arrangement. The activation of PRs is coupled to the calcium permeability of their coreceptor (Orco (see TC# 1.A.69.1.1)) or putatively with G proteins (Lin et al. 2021). Using the PR BmOR3 from the silk moth B. mori and its coreceptor BmOrco as a template, Lin et al. 2021 showed that an agonist-induced conformational change of BmOR3 is transmitted to BmOrco through TMS7s of both receptors, resulting in the activation of BmOrco. Key interactions, including an ionic lock and a hydrophobic zipper, are essential for mediating the functional coupling between BmOR3 and BmOrco. BmOR3 also selectively coupled with Gi proteins, which is dispensable for BmOrco coupling. Moreover, trans-7TM BmOR3 recruited arrestin (see TC# 8.A.136) in an agonist-dependent manner, which indicated an important role for BmOR3-BmOrco complex formation in ionotropic functions. Thus, the coupling of G protein and arrestin to a prototype trans-7TMS PR, BmOR3, has been demonstrated (Lin et al. 2021).

Eukaryota
Opisthokonta
OR3 of Bombyx mori (Silk moth)
1.A.69.5.1









Odorant receptor 85b (or85b) of 302 aas and 5 putative TMSs.  Binds the odorant, heptanone, for activation; 2-nananone is a competitive antagonist.  The second half of TMS3 is involved in odorant binding and activation (Nichols and Luetje 2010).

Eukaryota
Metazoa
Or85b of Drosophila melanogaster
1.A.69.6.1









Odorant receptor 22 of 312 aas and 6 TMSs

Eukaryota
Metazoa
Or22 of Bombyx mori
1.A.69.6.2









Odorant receptor 17 of 401 aas and 8 TMSs

Eukaryota
Metazoa
Or17 of Bombyx mori (Silk moth)
1.A.69.7.1









Odorant recpetor 278 if 385 aas and 8 TMSs

Eukaryota
Metazoa
Or278 of Tribolium castaneum (Red flour beetle)
1.A.69.7.2









Odorant receptor 205 of 406 aas and 9 putative TMSs.

Eukaryota
Metazoa
Or205 of Tribolium castaneum (Red flour beetle)