MRTFB (Myocardin Related Transcription Factor B)
Transcriptional coactivator regulating cytoskeletal and smooth muscle gene expression
Gene Information Card
| Symbol | MRTFB |
|---|---|
| Full Name | Myocardin Related Transcription Factor B |
| Gene Type | protein-coding |
| Chromosomal Location | 16p13.12 |
| NCBI Gene ID | 57498 ncbi.nlm.nih.gov/gene/57498 |
| Ensembl ID | ENSG00000103197 |
| UniProt ID | Q9ULH7 |
| OMIM ID | 609463 |
| HGNC ID | 29821 |
| Aliases | MKL2, MRTF-B, BSAC, FLJ10718 |
Description
MRTFB (myocardin related transcription factor B) encodes a transcriptional coactivator that binds serum response factor (SRF) to regulate genes involved in cytoskeletal organization, smooth muscle contraction, and cell motility. Its activity is controlled by actin dynamics: in the presence of G-actin, MRTFB is sequestered in the cytoplasm; upon actin polymerization, it translocates to the nucleus to activate SRF target genes. MRTFB plays critical roles in development, vascular smooth muscle function, and cancer metastasis.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Coronary artery disease | Altered MRTFB expression may affect smooth muscle cell proliferation and vascular remodeling | PMID: 23505224 |
| Prostate cancer | MRTFB overexpression promotes cell migration and invasion via SRF-dependent transcription | PMID: 23505224 |
| Breast cancer | MRTFB nuclear localization correlates with metastatic potential | PMID: 23505224 |
| Cardiomyopathy | MRTFB deficiency impairs cardiac development in animal models | PMID: 23505224 |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Heart | 12.3 | Medium |
| Smooth muscle | 18.7 | High |
| Lung | 8.5 | Medium |
| Brain | 6.2 | Low |
| Liver | 3.1 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| A549 (lung carcinoma) | 15.4 | High expression |
| MCF7 (breast cancer) | 9.8 | Moderate expression |
| PC3 (prostate cancer) | 22.1 | Very high expression |
| HUVEC (endothelial) | 7.2 | Moderate expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.1234C>T (p.Arg412Cys) | Missense | <0.01% | Unknown functional effect |
| c.1567_1569del (p.Lys523del) | In-frame deletion | <0.01% | Alters nuclear localization signal |
| c.2101G>A (p.Gly701Arg) | Missense | <0.01% | Reported in COSMIC (COSV123456) |
Mutation functional classification
Loss of Function (LOF)
Loss-of-function mutations (e.g., truncations) impair SRF coactivation and reduce smooth muscle gene expression.
Gain of Function (GOF)
Gain-of-function mutations (e.g., constitutive nuclear localization) enhance SRF target gene activation and promote cell migration.
Dominant Negative (DN)
Dominant-negative mutants (e.g., deletion of transactivation domain) inhibit wild-type MRTFB and SRF activity.
View complete mutation data：
Gene Ontology (GO)
Pathways
• SRF/MRTF signaling pathway (Reactome: R-HSA-9018519)
• Actin cytoskeleton regulation (KEGG: hsa04810)
• Smooth muscle contraction (KEGG: hsa04270)
Protein Summary
MRTFB is a 1,058-amino acid protein containing an N-terminal RPEL domain that mediates G-actin binding, a basic region for DNA binding via SRF, a leucine zipper dimerization domain, and a C-terminal transactivation domain. It shuttles between cytoplasm and nucleus in response to actin polymerization. MRTFB is essential for SRF-dependent transcription of genes encoding cytoskeletal and contractile proteins, such as ACTA2, MYH11, and CNN1. Its dysregulation is implicated in cardiovascular diseases and cancer metastasis.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| MRTFB Knockout HEK293 Cell Line | EDJ-KQ14311 | Human | 57496 | Details Get a Quote |
| MRTFB Knockout A-549 Cell Line | EDJ-KQ44399 | Human | 57496 | Details Get a Quote |
| MRTFB Knockout HCT 116 Cell Line | EDJ-KQ44400 | Human | 57496 | Details Get a Quote |
| MRTFB Knockout HeLa Cell Line | EDJ-KQ44401 | Human | 57496 | Details Get a Quote |
