MYO7 - myosin VII | Elisa - Clia - Antibody - Protein

Background

Myosin VII (MYO7) is a member of the myosin superfamily, which includes motor proteins that interact with actin filaments to generate cellular movement and transport. MYO7 is specifically known for its roles in sensory functions, particularly in the inner ear and retina. It is crucial for the proper functioning of hair cells in the cochlea, which are essential for hearing, and in photoreceptor cells in the retina, which are necessary for vision. Mutations in the MYO7A gene, which encodes myosin VIIA, are linked to several genetic disorders, including Usher syndrome type 1B and non-syndromic deafness.

Protein Structure

Myosin VII is a complex protein consisting of several distinct domains:

• N-terminal motor domain: This domain contains the ATPase activity necessary for motor function, allowing the protein to convert chemical energy into mechanical work.
• Neck region: This region contains IQ motifs that bind light chains, which are crucial for the protein's function and regulation.
• Coiled-coil domain: This domain facilitates dimerization, allowing two myosin VII molecules to form a functional dimer.
• C-terminal tail domain: This domain includes MyTH4 and FERM domains, which are involved in interactions with other proteins and cellular membranes.

Classification and Subtypes

Myosin VII belongs to the unconventional myosins, which are distinct from the more familiar class II myosins involved in muscle contraction. The primary subtype of myosin VII is myosin VIIA, encoded by the MYO7A gene. No significant subtypes have been identified within the myosin VII class, but different isoforms and mutations of myosin VIIA can lead to varying functional consequences and disease phenotypes.

Function and Biological Significance

Myosin VII plays several vital roles in cellular processes:

• Hearing: In the inner ear, myosin VIIA is critical for the function of hair cells, which convert mechanical sound vibrations into electrical signals.
• Vision: In the retina, myosin VIIA is involved in the transport of melanosomes in retinal pigment epithelial cells and the proper functioning of photoreceptor cells.
• Cell adhesion and migration: Myosin VIIA interacts with integrins and other cell adhesion molecules, influencing cell migration and tissue organization.

Clinical Issues

Mutations in the MYO7A gene can lead to various genetic disorders:

• Usher Syndrome Type 1B: This condition is characterized by congenital deafness, balance problems, and progressive vision loss due to retinitis pigmentosa.
• Non-syndromic Deafness: Specific mutations in MYO7A can cause isolated hearing loss without the other symptoms of Usher syndrome.
• Retinal Degeneration: MYO7A mutations can lead to progressive loss of vision due to defects in photoreceptor cells and retinal pigment epithelium function.

Summary

Myosin VII is a crucial motor protein involved in sensory functions, particularly in the auditory and visual systems. It plays a significant role in the mechanics of hearing and vision, and mutations in the MYO7A gene can result in severe genetic disorders such as Usher syndrome and non-syndromic deafness. Understanding the structure and function of myosin VII provides essential insights into its role in cellular processes and the molecular basis of related diseases.