Protein: Proton channel OTOP1 (Q7ZWK8)
Organism: Danio rerio (Zebrafish) (Brachydanio rerio)
Function: Proton-selective ion channel. Biphasically modulated by acid and alkali, mediating proton influx and efflux in response to extracellular acid and base stimulation, respectively (By similarity). May be involved in acid and base perception (By similarity). Sensor for ammonium chloride (NH(4)Cl) in taste receptor cells. NH(4)Cl acts by increasing the intracellular pH, thereby generating a driving force for proton entry through OTOP1 channel. Plays a role in the regulation of Ca(2+) flux in response to purigenic (ATP, ADP and UDP) stimuli, leading to increase in cytosolic Ca(2+) due to influx of extracellular calcium. May play this role by inhibiting P2Y purinoceptor-mediated Ca(2+) release in a Ca(2+)-dependent manner and promote an influx of Ca(2+) in response to ATP. Through this mechanism and possibly others, plays a role in the formation and function of calcium carbonate-based structures in the vestibular system of the inner ear, called otoconia, that sense gravity and linear acceleration
Subcellular location: Cell membrane; Multi-pass membrane protein. Cell projection, microvillus. Note=Found in the gelatinous membrane overlying the inner ear macular epithelium. Also detected in the apical microvilli in inner ear supporting cells
Sequence: MVEHGGTDSMWLNKYNPAAASSASSSSSSDAENKLFSRLKVSLTKKYPQKNAELLSAQYGTNLLLLGVSVMLALAAQSGPVKEEHLLSFITVLMLVQLVWMLCYMIRRERERSPVPERDAHAGASWIRGGLTMLALLSLIMDAFRIGYFVGYHSCISAALGVYPIVHALHTISQVHFLWFHIKDVIKKYETFERFGVIHAVFTNLLLWCNGVMSETEHFMHNHRRRLIEMGYANLSTVDVQPHCNCTTSVCSMFSTSLYYLYPFNIEYHIFVSAMLFVMWKNIGRTLDRHSNRKRRSTGSTGLLLGPLGGLVALASSVSVLVVYLIHLEKTEEMHEAAVSMFYYYGVAMMACMCVGSGTGLLVYRMENRPMDTGSNPARTLDTELLLASSLGSWLMSWCSVVASVAEAGQKSPSFSWTSLTYSLLLVLEKCIQNLFIVESLYRRHSEEEEDAAAPQVFSVAVPPYDGILNHGYEAHDKHREAEPAAGSHALSRKQPDAPLPAGQRLDVTPGRKRQILKNICMFLFMCNISLWILPAFGCRPQYDNPLENETFGTSVWTTVLNVAIPLNLFYRMHSVASLFEVFRKV
InterPro domains: - IPR004878: Otopetrin (family) [21-585]
Gene Ontology annotations:
Molecular Function (MF): GO:0003674 (molecular function), GO:0005488 (binding), GO:0005215 (transporter activity), GO:0036094 (small molecule binding), GO:0008289 (lipid binding), GO:0022857 (transmembrane transporter activity), GO:0097159 (organic cyclic compound binding), GO:0005515 (protein binding), GO:0043178 (alcohol binding), GO:0005496 (steroid binding), GO:0015075 (monoatomic ion transmembrane transporter activity), GO:0042802 (identical protein binding), GO:0022803 (passive transmembrane transporter activity), GO:0015318 (inorganic molecular entity transmembrane transporter activity), GO:0005216 (monoatomic ion channel activity), GO:0022890 (inorganic cation transmembrane transporter activity), GO:0015485 (cholesterol binding), GO:0015267 (channel activity), GO:0008324 (monoatomic cation transmembrane transporter activity), GO:0032934 (sterol binding), GO:0005261 (monoatomic cation channel activity), GO:0015078 (proton transmembrane transporter activity), GO:0015252 (proton channel activity)
Biological Process (BP): GO:0008150 (biological process), GO:0051179 (localization), GO:0051179 (localization), GO:0032502 (developmental process), GO:0009987 (cellular process), GO:0032501 (multicellular organismal process), GO:0048856 (anatomical structure development), GO:0007275 (multicellular organism development), GO:0009653 (anatomical structure morphogenesis), GO:0055085 (transmembrane transport), GO:0051234 (establishment of localization), GO:0048646 (anatomical structure formation involved in morphogenesis), GO:0048840 (otolith development), GO:0009887 (animal organ morphogenesis), GO:0048598 (embryonic morphogenesis), GO:0009888 (tissue development), GO:0098660 (inorganic ion transmembrane transport), GO:0006810 (transport), GO:0048513 (animal organ development), GO:0009790 (embryo development), GO:0034220 (monoatomic ion transmembrane transport), GO:0048839 (inner ear development), GO:0098655 (monoatomic cation transmembrane transport), GO:0098662 (inorganic cation transmembrane transport), GO:0048568 (embryonic organ development), GO:0042472 (inner ear morphogenesis), GO:0032474 (otolith morphogenesis), GO:0048562 (embryonic organ morphogenesis), GO:0007423 (sensory organ development), GO:0090596 (sensory organ morphogenesis), GO:0031214 (biomineral tissue development), GO:0006811 (monoatomic ion transport), GO:0042471 (ear morphogenesis), GO:0006812 (monoatomic cation transport), GO:0043583 (ear development), GO:1902600 (proton transmembrane transport)
Cellular Component (CC): GO:0005575 (cellular component), GO:0110165 (cellular anatomical entity), GO:0071944 (cell periphery), GO:0016020 (membrane), GO:0005886 (plasma membrane)