In the inner ear, stereocilia are the mechanosensing organelles of hair cells, which respond to fluid motion in numerous types of animals for various functions, including hearing and balance. They are about 10–50 micrometers in length and share some similar features of microvilli. The hair cells turn the fluid pressure and other mechanical stimuli into electric stimuli via the many microvilli that make up stereocilia rods. Stereocilia exist in the auditory and vestibular systems.
T-box transcription factor TBX1 also known as T-box protein 1 and testis-specific T-box protein is a protein that in humans is encoded by the TBX1 gene. Genes in the T-box family are transcription factors that play important roles in the formation of tissues and organs during embryonic development. To carry out these roles, proteins made by this gene family bind to specific areas of DNA called T-box binding element (TBE) to control the expression of target genes.
Gap junction beta-2 protein (GJB2), also known as connexin 26 (Cx26) — is a protein that in humans is encoded by the GJB2 gene.
Harmonin is a protein that in humans is encoded by the USH1C gene. It is expressed in sensory cells of the inner ear and retina, where it plays a role in hearing, balance, and vision. Mutations at the USH1C locus cause Usher syndrome type 1c and nonsyndromic sensorineural deafness.
Cadherin-23 is a protein that in humans is encoded by the CDH23 gene.
Protocadherin-15 is a protein that in humans is encoded by the PCDH15 gene.
Usher syndrome type-1G protein is a protein that in humans is encoded by the USH1G gene.
Gap junction beta-6 protein (GJB6), also known as connexin 30 (Cx30) — is a protein that in humans is encoded by the GJB6 gene. Connexin 30 (Cx30) is one of several gap junction proteins expressed in the inner ear. Mutations in gap junction genes have been found to lead to both syndromic and nonsyndromic deafness. Mutations in this gene are associated with Clouston syndrome.
Tyrosinase-related protein 1, also known as TYRP1, is an intermembrane enzyme which in humans is encoded by the TYRP1 gene.
P protein, also known as melanocyte-specific transporter protein or pink-eyed dilution protein homolog, is a protein that in humans is encoded by the oculocutaneous albinism II (OCA2) gene. The P protein is believed to be an integral membrane protein involved in small molecule transport, specifically of tyrosine—a precursor of melanin. Certain mutations in OCA2 result in type 2 oculocutaneous albinism. OCA2 encodes the human homologue of the mouse p gene.
Eyes absent homolog 1 is a protein that in humans is encoded by the EYA1 gene.
Mitochondrial import inner membrane translocase subunit Tim8 A, also known as deafness-dystonia peptide or protein is an enzyme that in humans is encoded by the TIMM8A gene. This translocase has similarity to yeast mitochondrial proteins that are involved in the import of metabolite transporters from the cytoplasm into the mitochondrial inner membrane. The gene is mutated in deafness-dystonia syndrome and it is postulated that MTS/DFN-1 is a mitochondrial disease caused by a defective mitochondrial protein import system.
Alpha-tectorin is a protein that in humans is encoded by the TECTA gene.
Myosin-14 is a protein that in humans is encoded by the MYH14 gene.
Otoferlin is a protein that in humans is encoded by the OTOF gene. It is involved in vesicle membrane fusion, and mutations in the OTOF gene are associated with a genetic form of deafness.
Transmembrane channel-like protein 1 is a protein that in humans is encoded by the TMC1 gene. TMC1 contains six transmembrane domains with both the C and N termini on the endoplasmic side of the membrane, as well as a large loop between domains 4 and 5. This topology is similar to that of transient receptor potential channels (TRPs), a family of proteins involved in the perception of senses such as temperature, taste, pressure, and vision. TMC1 has been located in the post-natal mouse cochlea, and knockouts for TMC1 and TMC2 result in both auditory and vestibular deficits indicating TMC1 is a molecular part of auditory transduction.
Myosin-XV is a protein that in humans is encoded by the MYO15A gene.
Espin, also known as autosomal recessive deafness type 36 protein or ectoplasmic specialization protein, is a protein that in humans is encoded by the ESPN gene. Espin is a microfilament binding protein.
Sine oculis-binding protein homolog (SOBP) also known as Jackson circler protein 1 (JXC1) is a protein that in humans is encoded by the SOBP gene. The first SOBP gene was identified in Drosophila melanogaster in a yeast two-hybrid screen that used the SIX domain of the Sine oculis protein as bait. In most genomes, which harbor SOBP, the gene is present as a single copy.
Otoancorin is a protein found in the vertebrate inner ear, on the sensory epithelia where it connects to the gel matrix.
