OTOP1: Otoperlin 1, a Proton-Selective Ion Channel in Sour Taste and Inner Ear Function
Comprehensive biomedical reference for OTOP1 gene, encoding a proton channel involved in sour taste transduction and vestibular function.
Gene Information Card
| Symbol | OTOP1 |
|---|---|
| Full Name | otoperlin 1 |
| Gene Type | protein-coding |
| Chromosomal Location | 4p15.32 |
| NCBI Gene ID | 133060 ncbi.nlm.nih.gov/gene/133060 |
| Ensembl ID | ENSG00000164134 |
| UniProt ID | Q7Z7M0 |
| OMIM ID | 607829 |
| HGNC ID | 18790 |
| Aliases | OTOP, MGC138499, MGC138501 |
Description
OTOP1 encodes otoperlin 1, a proton-selective ion channel that is essential for sour taste perception in type III taste receptor cells. It is also expressed in the inner ear, where it contributes to vestibular function. OTOP1 is a member of the otoperlin family, which includes OTOP2 and OTOP3. The protein forms a voltage-gated proton channel that is activated by extracellular acidification, mediating the detection of sour stimuli. Mutations in OTOP1 have been associated with hearing loss and vestibular dysfunction in animal models.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Hearing loss (non-syndromic) | Loss-of-function mutations in OTOP1 disrupt proton conductance in inner ear hair cells, impairing mechanoelectrical transduction. | ClinVar, OMIM |
| Vestibular dysfunction | OTOP1 deficiency leads to balance deficits in mice; human correlation under investigation. | NCBI Gene, OMIM |
| Sour taste perception defects | OTOP1 is the primary sour taste receptor; null mutations abolish sour taste in mice. | NCBI Gene, UniProt |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Tongue (taste buds) | 12.5 | Medium |
| Inner ear (vestibular organs) | 8.3 | Medium |
| Stomach | 5.1 | Low |
| Kidney | 3.2 | Low |
| Brain (cerebellum) | 1.8 | Not detected |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HEK293 | 0.0 | No endogenous expression; used for heterologous expression studies |
| Taste bud cells (type III) | High | Endogenous expression; sour taste transduction |
| Hair cells (utricle) | Medium | Vestibular function |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.154C>T (p.Arg52Cys) | Missense | Rare | Reduced proton conductance; associated with hearing loss in mice |
| c.1018G>A (p.Gly340Ser) | Missense | Rare | Loss of channel function; sour taste deficit in mice |
| c.1234delC (p.Leu412Trpfs*13) | Frameshift | Not reported in humans | Null allele; vestibular dysfunction in mouse models |
Mutation functional classification
Loss of Function (LOF)
Missense and frameshift mutations that abolish or severely reduce proton channel activity, leading to sour taste loss and vestibular defects.
Gain of Function (GOF)
Not reported for OTOP1.
Dominant Negative (DN)
Not reported for OTOP1.
View complete mutation data：
Gene Ontology (GO)
| • proton channel activity (GO:0015252) | • voltage-gated ion channel activity (GO:0005244) |
| • sour taste receptor activity (GO:0033038) | • plasma membrane (GO:0005886) |
| • integral component of membrane (GO:0016021) | • detection of chemical stimulus involved in sensory perception of sour taste (GO:0050914) |
| • vestibular receptor cell development (GO:0060113) |
Pathways
• Sour taste transduction (KEGG: hsa04742)
• Ion channel transport (Reactome: R-HSA-983712)
Protein Summary
Otoperlin 1 (OTOP1) is a 6-transmembrane domain proton channel that localizes to the plasma membrane of type III taste receptor cells and inner ear hair cells. It is activated by extracellular protons (pH < 6.5) and mediates a voltage-dependent inward proton current. The channel is essential for sour taste perception and contributes to vestibular function. OTOP1 is not expressed in the cochlea but is found in vestibular hair cells, where it may modulate mechanotransduction. The protein has no known enzymatic activity and functions as a homomultimer.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| OTOP1 Knockout HEK293 Cell Line | EDJ-KQ9310 | Human | 133060 | Details Get a Quote |
| OTOP1 Knockout HeLa Cell Line | EDJ-KQ58324 | Human | 133060 | Details Get a Quote |
| OTOP1 Knockout A-549 Cell Line | EDJ-KQ66812 | Human | 133060 | Details Get a Quote |
| OTOP1 Knockout HCT 116 Cell Line | EDJ-KQ75215 | Human | 133060 | Details Get a Quote |
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