USH1C
Description
The USH1C (USH1 protein network component harmonin) is a protein-coding gene located on chromosome 11.
Harmonin is a protein encoded by the USH1C gene in humans. It is expressed in sensory cells of the inner ear and retina, where it plays a vital role in hearing, balance, and vision. Mutations in the USH1C gene cause Usher syndrome type 1c and nonsyndromic sensorineural deafness. The USH1C gene is located on chromosome 11 and comprises 28 exons. Alternative splicing generates multiple mRNA transcript variants, some of which are associated with rare Usher syndrome and nonsyndromic sensorineural deafness phenotypes. The encoded harmonin protein exhibits multiple isoforms due to alternative splicing, including a standard isoform with 552 amino acids. Harmonin contains a PDZ domain, which aids in anchoring the protein to the cell membrane and cytoskeletal components. Harmonin is found at the apex of inner hair cells (IHCs), which convert mechanical signals from sound waves into electrical signals interpreted by the brain as sound. IHCs possess an apical bundle of actin-rich stereocilia that vary in height and are connected to each other by flexible tip links. Tip links are protein complexes composed of cadherin 23 (CDH23) and protocadherin 15 (PCDH15).
The USH1C gene encodes harmonin, a scaffolding protein that plays a crucial role in mechanotransduction within cochlear hair cells. It forms a functional network with USH1G, CDH23, and MYO7A, essential for the conversion of sound waves into electrical signals. Harmonin is also required for the normal development and maintenance of cochlear hair cell bundles. As part of the intermicrovillar adhesion complex (IMAC), harmonin contributes to brush border differentiation by regulating microvilli organization and length. It acts as a central regulator in IMAC assembly, recruiting CDHR2, CDHR5, and MYO7B to the microvilli tips.
USH1C is also known as AIE-75, DFNB18, DFNB18A, NY-CO-37, NY-CO-38, PDZ-45, PDZ-73, PDZ-73/NY-CO-38, PDZ73, PDZD7C, ush1cpst.
Associated Diseases
- Deafness, neurosensory, autosomal recessive 18
- Usher syndrome, type IC
- Usher syndrome, type I
- Usher syndrome type 1
