MAFB Gene: V-Maf Avian Musculoaponeurotic Fibrosarcoma Oncogene Homolog B
A key transcription factor in hematopoietic differentiation and pancreatic development, implicated in multicentric carpotarsal osteolysis syndrome and multiple myeloma.
Gene Information Card
| Symbol | MAFB |
|---|---|
| Full Name | MAF bZIP transcription factor B |
| Gene Type | protein-coding |
| Chromosomal Location | 20q12 |
| NCBI Gene ID | 9935 ncbi.nlm.nih.gov/gene/9935 |
| Ensembl ID | ENSG00000100225 |
| UniProt ID | Q9Y5Q3 |
| OMIM ID | 608968 |
| HGNC ID | 6777 |
| Aliases | KRML, MGC43127, bZIP transcription factor B |
Description
MAFB (MAF bZIP transcription factor B) encodes a basic leucine zipper (bZIP) transcription factor that belongs to the MAF family. It plays critical roles in the regulation of hematopoiesis, particularly in monocyte/macrophage differentiation, and in pancreatic islet cell development. Mutations in MAFB are associated with multicentric carpotarsal osteolysis syndrome (MCTO) and have been implicated in multiple myeloma through chromosomal translocations and overexpression.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Multicentric carpotarsal osteolysis syndrome (MCTO) | Loss-of-function mutations in MAFB disrupt normal osteoclast and bone development, leading to progressive bone loss and carpotarsal osteolysis. | ClinVar, OMIM |
| Multiple myeloma | Chromosomal translocations (e.g., t(14;20)(q32;q12)) involving MAFB lead to its overexpression, contributing to plasma cell malignancy. | COSMIC, NCBI, OMIM |
| Diabetes mellitus (type 2) | MAFB is essential for pancreatic beta-cell development and function; variants may alter insulin secretion. | OMIM, NCBI |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Kidney | 12.5 | Medium |
| Pancreas | 8.2 | Medium |
| Bone marrow | 6.8 | Low |
| Spleen | 5.1 | Low |
| Lung | 3.4 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| K-562 (leukemia) | 15.3 | High expression |
| HEK 293 (embryonic kidney) | 9.7 | Medium expression |
| HeLa (cervical carcinoma) | 4.2 | Low expression |
| MCF7 (breast cancer) | 2.1 | Very low expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.266C>T (p.Ser89Leu) | Missense | Rare | Loss of DNA-binding activity; associated with MCTO |
| c.437G>A (p.Arg146Gln) | Missense | Rare | Impaired transcriptional activation; MCTO |
| t(14;20)(q32;q12) | Translocation | Somatic in multiple myeloma | Overexpression of MAFB driven by IGH enhancer |
| c.1A>G (p.Met1Val) | Start loss | Rare | Complete loss of protein; MCTO |
Mutation functional classification
Loss of Function (LOF)
Missense and start-loss mutations in MAFB (e.g., p.Ser89Leu, p.Met1Val) result in loss of DNA binding or protein production, leading to haploinsufficiency and MCTO.
Gain of Function (GOF)
Chromosomal translocations (e.g., t(14;20)) cause MAFB overexpression in multiple myeloma, acting as an oncogenic driver.
Dominant Negative (DN)
Some missense variants may produce a protein that interferes with wild-type MAFB function, though dominant-negative effects are not well-documented for MAFB.
View complete mutation data：
Gene Ontology (GO)
Pathways
• Hematopoietic cell lineage (KEGG:04640)
• Transcriptional misregulation in cancer (KEGG:05202)
• Signaling pathways regulating pluripotency of stem cells (KEGG:04550)
Protein Summary
MAFB is a 323-amino acid bZIP transcription factor that forms homodimers or heterodimers with other MAF family members. It binds to MAF recognition elements (MARE) in target gene promoters to regulate transcription. The protein contains an N-terminal transactivation domain and a C-terminal bZIP domain. MAFB is essential for monocyte/macrophage differentiation, osteoclast development, and pancreatic beta-cell maturation. Its dysregulation contributes to skeletal disorders and hematologic malignancies.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| MAFB Knockout HEK293 Cell Line | EDJ-KQ3355 | Human | 9935 | Details Get a Quote |
| MAFB Knockout HeLa Cell Line | EDJ-KQ25012 | Human | 9935 | Details Get a Quote |
| MAFB Knockout A-549 Cell Line | EDJ-KQ63761 | Human | 9935 | Details Get a Quote |
| MAFB Knockout HCT 116 Cell Line | EDJ-KQ72220 | Human | 9935 | Details Get a Quote |
