MYO3A

The protein encoded by this gene belongs to the myosin superfamily. Myosins are actin-dependent motor proteins and are categorized into conventional myosins (class II) and unconventional myosins (classes I and III through XV) based on their variable C-terminal cargo-binding domains. Class III myosins, such as this one, have a kinase domain N-terminal to the conserved N-terminal motor domains and are expressed in photoreceptors. The protein encoded by this gene plays an important role in hearing in humans. Three different recessive, loss of function mutations in the encoded protein have been shown to cause nonsyndromic progressive hearing loss. Expression of this gene is highly restricted, with the strongest expression in retina and cochlea. [provided by RefSeq]

Full Name

myosin IIIA

Function

Probable actin-based motor with a protein kinase activity. Probably plays a role in vision and hearing (PubMed:12032315).

Required for normal cochlear hair bundle development and hearing. Plays an important role in the early steps of cochlear hair bundle morphogenesis. Influences the number and lengths of stereocilia to be produced and limits the growth of microvilli within the forming auditory hair bundles thereby contributing to the architecture of the hair bundle, including its staircase pattern. Involved in the elongation of actin in stereocilia tips by transporting the actin regulatory factor ESPN to the plus ends of actin filaments (By similarity).

Biological Process

Cochlea morphogenesis Source: UniProtKB
Protein autophosphorylation Source: UniProtKB
Response to stimulus Source: UniProtKB-KW
Sensory perception of sound Source: UniProtKB
Visual perception Source: UniProtKB-KW

Cellular Location

Cytoskeleton
Cytoplasm
Other locations
filopodium tip
stereocilium
Note: Increased localization at the filodium tip seen in the presence of MORN4.

Involvement in disease

Deafness, autosomal recessive, 30 (DFNB30):
A form of non-syndromic deafness characterized by bilateral progressive hearing loss, which first affects the high frequencies. Hearing loss begins in the second decade, and by age 50 is severe in high and middle frequencies and moderate at low frequencies.