TCDB is operated by the Saier Lab Bioinformatics Group
TCIDNameDomainKingdom/PhylumProtein(s)
1.A.110.1.1









OTOP1 of 600 aas and 12 TMSs in a 5 + 5 + 2 arrangement.  OTOP1 is a proton-selective ion channel enriched in acid-detecting taste receptor cells and is required for their zinc-sensitive proton conductance (Tu et al. 2018). Two related murine genes, Otop2 and Otop3, and a Drosophila ortholog also encode proton channels. Evolutionary conservation of the gene family and its widespread tissue distribution suggest a broad role for proton channels in physiology and pathophysiology (Tu et al. 2018).

Eukaryota
Metazoa
OTOP1 of Mus musculus
1.A.110.1.2









OTOP1 H+ channel of 612 aas and 10 TMSs (Tu et al. 2018). OTOP1 is a protein required for development of gravity-sensing otoconia in the vestibular system. It forms a proton-selective ion channel (Tu et al. 2018).

Eukaryota
Metazoa
OTOP1 of Homo sapiens
1.A.110.1.3









OTOP2 H+ channel of 562 aas and 10 TMSs in a 5 + 5 + 2 arrangement (Tu et al. 2018).

Eukaryota
Metazoa
OTOP2 of Homo sapiens
1.A.110.1.4









OTOP3 of 596 aas and 10 TMSs in a 5 + 5 + 2 TMS arrangement (Tu et al. 2018).

Eukaryota
Metazoa
OTOP3 of Homo sapiens
1.A.110.1.5









Zinc-sensitive proton channel, OTOP1, of 586 aas and 10 TMSs in a 5 + 5 + 2 TMS arrangement (Tu et al. 2018). It inhibits P2Y purinoceptors and modulates calcium homeostasis and influx of calcium in response to extracellular ATP. It is essential for the formation of otoliths in the inner ear of developing larvae and for the perception of gravity and acceleration (Söllner et al. 2004; Hughes et al. 2004). The 3-d structure has been determined by cryoEM (Saotome et al. 2019) (see family description). Mutations in the Otopetrin 1 gene in mice and fish produce an unusual bilateral vestibular pathology that involves the absence of otoconia without hearing impairment (Hurle et al. 2011).

Eukaryota
Metazoa
OTOP1 of Danio rerio (Zebrafish) (Brachydanio rerio)
1.A.110.1.6









OtoPetrin-like (Otpl6) of 581 aas and 12 TMSs.

Eukaryota
Metazoa
Otpl6 of Caenorhabditis elegans
1.A.110.1.7









OToPetrin-like protein, isoform D, of 647 aas and 12 or 13 TMSs in a 5 +7 or 8 TMS arrangement.

Eukaryota
Metazoa
OTOP, isoform D of Drosophila melanogaster (Fruit fly)
1.A.110.1.8









Putative otopetrin of 747 aas and 11 or 12 TMSs in a 1 + 3 + 7 or 8 TMS arrangement.

Eukaryota
Metazoa
Putative Otop protein of Schistosoma mansoni (Blood fluke)
1.A.110.1.9









The OTOP3 protopn channel protein of 681 aas and 12 TMSs. The cryo-EM structure along with functional characteristics have been described (Chen et al. 2019). XtOTOP3 forms a homodimer with each subunit containing 12 transmembrane helices that can be divided into two structurally homologous halves; each half assembles as an alpha-helical barrel that could serve as a proton conduction pore.

Eukaryota
Metazoa
OTOP3 of Xenopus tropicalis
1.A.110.1.10









Otop3 of 600 aas and 12 TMSs.  The high resolution 3-d structure has been determined by cryoEM (Saotome et al. 2019) (see family description). Applications of solution NMR for studying structure, dynamics, and interactions of polytopic integral membrane proteins has been reviewed (Danmaliki and Hwang 2020).

Eukaryota
Metazoa
Otop3 of Gallus gallus (chicken)