Skip to main content

MYO7A

Developmental stage

Detected in optic cup in 5.5 weeks-old embryos. Expressed in retinal pigment epithelium, cochlear and vestibular neuroepithelia, and olfactory epithelium at 8 weeks. At 19 weeks, present in both pigment epithelium and photoreceptor cells. At 24-28 weeks, expression in pigment epithelium and photoreceptor cells increases. Present in pigment epithelium and photoreceptor cells in adult.

Domain

The SAH (single alpha-helix) region is characterized by a high content of charged residues which are predicted to stabilize the alpha-helical structure by ionic bonds.

Function

Myosins are actin-based motor molecules with ATPase activity. Unconventional myosins serve in intracellular movements. Their highly divergent tails bind to membranous compartments, which are then moved relative to actin filaments. In the retina, plays an important role in the renewal of the outer photoreceptor disks. Plays an important role in the distribution and migration of retinal pigment epithelial (RPE) melanosomes and phagosomes, and in the regulation of opsin transport in retinal photoreceptors. In the inner ear, plays an important role in differentiation, morphogenesis and organization of cochlear hair cell bundles. Involved in hair-cell vesicle trafficking of aminoglycosides, which are known to induce ototoxicity (By similarity). Motor protein that is a part of the functional network formed by USH1C, USH1G, CDH23 and MYO7A that mediates mechanotransduction in cochlear hair cells. Required for normal hearing.

Involvement in disease

Usher syndrome 1B

USH1B

USH is a genetically heterogeneous condition characterized by the association of retinitis pigmentosa with sensorineural deafness. Age at onset and differences in auditory and vestibular function distinguish Usher syndrome type 1 (USH1), Usher syndrome type 2 (USH2) and Usher syndrome type 3 (USH3). USH1 is characterized by profound congenital sensorineural deafness, absent vestibular function and prepubertal onset of progressive retinitis pigmentosa leading to blindness.

None

The disease is caused by variants affecting the gene represented in this entry.

Deafness, autosomal recessive, 2

DFNB2

A form of non-syndromic sensorineural hearing loss. Sensorineural deafness results from damage to the neural receptors of the inner ear, the nerve pathways to the brain, or the area of the brain that receives sound information.

None

The disease is caused by variants affecting the gene represented in this entry.

Deafness, autosomal dominant, 11

DFNA11

A form of non-syndromic sensorineural hearing loss. Sensorineural deafness results from damage to the neural receptors of the inner ear, the nerve pathways to the brain, or the area of the brain that receives sound information. DFNA11 is characterized by onset after complete speech acquisition and subsequent gradual progression.

None

The disease is caused by variants affecting the gene represented in this entry.

Sequence similarities

Belongs to the TRAFAC class myosin-kinesin ATPase superfamily. Myosin family.

Tissue specificity

Expressed in the pigment epithelium and the photoreceptor cells of the retina. Also found in kidney, liver, testis, cochlea, lymphocytes. Not expressed in brain.

Cellular localization

  • Cytoplasm
  • Cytoplasm
  • Cell cortex
  • Cytoplasm
  • Cytoskeleton
  • Cell junction
  • Synapse
  • In the photoreceptor cells, mainly localized in the inner and base of outer segments as well as in the synaptic ending region (PubMed:8842737). In retinal pigment epithelial cells colocalizes with a subset of melanosomes, displays predominant localization to stress fiber-like structures and some localization to cytoplasmic puncta (PubMed:19643958, PubMed:27331610). Detected at the tip of cochlear hair cell stereocilia (PubMed:21709241). The complex formed by MYO7A, USH1C and USH1G colocalizes with F-actin (PubMed:21709241).

Alternative names

  • Unconventional myosin-VIIa
  • USH1B
  • MYO7A

Target type

Proteins

Molecular weight

254390Da