MYO9B: Myosin IXB Gene
A RhoGAP-containing unconventional myosin involved in cell motility, signaling, and immune regulation
Gene Information Card
| Symbol | MYO9B |
|---|---|
| Full Name | Myosin IXB |
| Gene Type | Protein coding |
| Chromosomal Location | 19p13.11 |
| NCBI Gene ID | 4650 ncbi.nlm.nih.gov/gene/4650 |
| Ensembl ID | ENSG00000099331 |
| UniProt ID | Q13459 |
| OMIM ID | 602129 |
| HGNC ID | 7606 |
| Aliases | MYR5, CELIAC4, FLJ11029, FLJ20537 |
Description
MYO9B encodes myosin IXB, an unconventional myosin motor protein that contains a Rho GTPase-activating protein (RhoGAP) domain. It functions as a molecular motor along actin filaments and negatively regulates RhoA signaling, thereby influencing cytoskeletal dynamics, cell migration, and immune cell function. Variants in MYO9B have been associated with susceptibility to celiac disease, inflammatory bowel disease, and other autoimmune conditions.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Celiac disease | MYO9B variants may alter intestinal barrier function and immune response to gluten, increasing disease risk | Genetic association studies (OMIM 602129) |
| Inflammatory bowel disease (Crohn's disease, ulcerative colitis) | Dysregulation of RhoA signaling due to MYO9B variants affects epithelial integrity and immune cell migration | Case-control studies and meta-analyses |
| Autoimmune thyroid disease | Shared genetic susceptibility with celiac disease; MYO9B polymorphisms implicated | GWAS and candidate gene studies |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Small intestine | 12.5 | Medium |
| Colon | 10.3 | Medium |
| Spleen | 8.7 | Low |
| Lung | 7.1 | Low |
| Brain | 5.2 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HeLa | 15.0 | Cervical adenocarcinoma |
| A549 | 12.3 | Lung carcinoma |
| HepG2 | 9.8 | Hepatocellular carcinoma |
| K562 | 6.5 | Chronic myeloid leukemia |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| rs2305764 (intronic variant) | SNV | ~30% in European populations | Associated with celiac disease risk |
| rs1545620 (missense, Ala1516Thr) | Missense | ~25% in European populations | May alter RhoGAP activity; linked to IBD |
| rs7259292 (intronic variant) | SNV | ~15% in European populations | Associated with ulcerative colitis |
Mutation functional classification
Loss of Function (LOF)
Rare nonsense or frameshift variants predicted to truncate the protein, likely reducing RhoGAP activity and disrupting actin-based motility.
Gain of Function (GOF)
Not well characterized; some missense variants may enhance RhoGAP activity, leading to excessive RhoA inhibition.
Dominant Negative (DN)
Not reported for MYO9B.
View complete mutation data：
Gene Ontology (GO)
| • actin filament binding | • ATP binding |
| • GTPase activator activity | • microtubule motor activity |
| • Rho GTPase activator activity | • actin cytoskeleton organization |
| • cell migration | • intracellular protein transport |
| • negative regulation of Rho protein signal transduction |
Pathways
• Rho GTPase cycle
• Actin cytoskeleton regulation
• Signaling by Rho family GTPases
Protein Summary
Myosin IXB is a 230 kDa unconventional myosin composed of an N-terminal motor domain, a neck region with IQ motifs, and a C-terminal tail containing a RhoGAP domain. It moves processively along actin filaments and simultaneously inactivates RhoA by stimulating its GTP hydrolysis. This dual motor-GAP activity allows MYO9B to regulate cell shape, adhesion, and migration, particularly in immune cells and epithelial barriers.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| MYO9B Knockout HEK293 Cell Line | EDJ-KQ982 | Human | 4650 | Details Get a Quote |
| MYO9B Knockout HCT 116 Cell Line | EDJ-KQ20005 | Human | 4650 | Details Get a Quote |
| MYO9B Knockout HeLa Cell Line | EDJ-KQ20006 | Human | 4650 | Details Get a Quote |
| MYO9B Knockout A-549 Cell Line | EDJ-KQ18684 | Human | 4650 | Details Get a Quote |
