MYO7A Gene - Myosin VIIA: Function, Mutations, and Associated Diseases

MYO7A encodes myosin VIIA, an unconventional myosin motor protein that functions as an actin-based molecular motor. It is critical for the structural integrity and function of hair cell stereocilia in the inner ear and for the transport of proteins in photoreceptor cells of the retina. Mutations in MYO7A are the most common cause of Usher syndrome type 1B, characterized by congenital sensorineural hearing loss, vestibular dysfunction, and retinitis pigmentosa. Additionally, mutations can cause non-syndromic autosomal dominant (DFNA11) and autosomal recessive (DFNB2) hearing loss.

Tissue Expression

Cell Line Expression

Hotspot Mutations

Mutation functional classification

• Usher syndrome pathway

• Phototransduction cascade

• Actin cytoskeleton regulation

Myosin VIIA is a 2547-amino acid unconventional myosin with an N-terminal motor domain, a neck region with IQ motifs that bind calmodulin, and a C-terminal tail domain containing a myosin tail homology 4 (MyTH4) domain, a band 4.1/ezrin/radixin/moesin (FERM) domain, and an SH3 domain. It functions as a dimeric actin-based motor that transports cargo along actin filaments. In inner ear hair cells, it is essential for stereocilia bundle cohesion and mechanotransduction. In the retina, it is involved in melanosome transport in retinal pigment epithelium and opsin transport in photoreceptors.