MYO3B: Myosin IIIB
A member of the class III myosin family involved in sensory hair cell function and hearing
Gene Information Card
| Symbol | MYO3B |
|---|---|
| Full Name | myosin IIIB |
| Gene Type | protein-coding |
| Chromosomal Location | 2q31.1 |
| NCBI Gene ID | 140469 ncbi.nlm.nih.gov/gene/140469 |
| Ensembl ID | ENSG00000171992 |
| UniProt ID | Q8WXR4 |
| OMIM ID | 610040 |
| HGNC ID | 15576 |
| Aliases | DFNB93, MYO3B, myosin IIIB |
Description
MYO3B encodes myosin IIIB, an actin-based motor protein with an N-terminal kinase domain. It is predominantly expressed in sensory hair cells of the inner ear and is essential for stereocilia development and maintenance. Mutations in MYO3B cause autosomal recessive non-syndromic hearing loss (DFNB93).
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Autosomal recessive non-syndromic hearing loss 93 (DFNB93) | Loss-of-function mutations disrupt actin-based transport in hair cell stereocilia, leading to progressive hearing loss. | ClinVar, OMIM |
| Usher syndrome (possible modifier) | Potential involvement in retinal and cochlear hair cell function, though direct evidence is limited. | OMIM |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Inner ear (cochlea) | High | Tissue-specific |
| Testis | Low | GTEx |
| Brain (cerebellum) | Low | GTEx |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HEK293 | Low | Overexpression studies |
| Hair cell lines (e.g., UB/OC-1) | High | Endogenous expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.1616C>T (p.Pro539Leu) | Missense | Rare | Likely loss-of-function; associated with DFNB93 |
| c.2440C>T (p.Arg814*) | Nonsense | Rare | Truncating; loss-of-function; hearing loss |
| c.1327G>A (p.Gly443Arg) | Missense | Rare | Likely damaging; reduced motor activity |
Mutation functional classification
Loss of Function (LOF)
Nonsense and missense mutations that impair actin-binding or motor activity lead to hearing loss (DFNB93).
Gain of Function (GOF)
Not reported.
Dominant Negative (DN)
Not reported.
View complete mutation data：
Gene Ontology (GO)
| • actin binding | • ATP binding |
| • calmodulin binding | • kinase activity |
| • motor activity | • actin filament-based movement |
| • sensory perception of sound |
Pathways
• Actin cytoskeleton regulation
• Stereocilia development
• Myosin-mediated transport
Protein Summary
Myosin IIIB is a 1615-amino acid protein with an N-terminal serine/threonine kinase domain, a motor domain, and a C-terminal tail that binds actin. It localizes to stereocilia tips and is required for their elongation and maintenance. The kinase domain autophosphorylates and regulates motor activity.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| MYO3B Knockout HEK293 Cell Line | EDJ-KQ9775 | Human | 140469 | Details Get a Quote |
| MYO3B Knockout HeLa Cell Line | EDJ-KQ58433 | Human | 140469 | Details Get a Quote |
| MYO3B Knockout A-549 Cell Line | EDJ-KQ66922 | Human | 140469 | Details Get a Quote |
| MYO3B Knockout HCT 116 Cell Line | EDJ-KQ75326 | Human | 140469 | Details Get a Quote |
