{{.infobox .infobox-gene}}
| | |
|---|---| [1]
| Symbol | CLRN1 |
| Full Name | Clarin 1 |
| Chromosome | 3p21.3 |
| NCBI Gene | 55630 |
| OMIM | 606397 |
| Ensembl | ENSG00000122218 |
| UniProt | Q9NYQ5 |
Usher syndrome type 3A, Sensorineural hearing loss, Retinitis pigmentosa
CLRN1 encodes clarin 1, a member of the tetraspanin family of proteins, which are characterized by four transmembrane domains. Clarin 1 is essential for the formation and maintenance of stereocilia in inner ear hair cells and for photoreceptor cell function 1.
Clarin 1 localizes to the plasma membrane of hair cell stereocilia and photoreceptor cells. The protein forms oligomeric complexes and interacts with other Usher syndrome proteins including:
The exact signaling pathway of clarin 1 remains under investigation, but it appears to function in organizing the protein complexes necessary for stereocilia bundle formation and maintenance 2.
As a tetraspanin, clarin 1 likely participates in:
CLRN1 is expressed primarily in:
The protein is expressed throughout development, with particular importance during late embryonic and early postnatal periods when stereocilia bundles mature.
Mutations in CLRN1 cause Usher syndrome type 3A, characterized by:
The phenotype is variable, and some mutations may cause isolated hearing loss without retinal involvement.
CLRN1 mutations lead to progressive degeneration of hair cells, representing a model of sensory neuron degeneration:
Understanding these mechanisms may inform:
The photoreceptor degeneration in Usher syndrome type 3A shares features with:
Clarin 1 is a tetraspanin with characteristic features:
The large extracellular loop (EC2) contains:
Clarin 1 forms homooligomers and heterooligomers with other tetraspanins, which may be important for its function in membrane microdomains.
While the exact signaling cascade is not fully characterized, clarin 1 participates in:
In photoreceptor cells, clarin 1 may function in:
Calcium signaling: May modulate calcium homeostasis. Calcium signaling. ↩︎