BAX Gene: BCL2 Associated X, Apoptosis Regulator
A key pro-apoptotic regulator in the BCL2 family, involved in mitochondrial outer membrane permeabilization and programmed cell death.
Gene Information Card
| Symbol | BAX |
|---|---|
| Full Name | BCL2 associated X, apoptosis regulator |
| Gene Type | protein-coding |
| Chromosomal Location | 19q13.33 (GRCh38) |
| NCBI Gene ID | 581 ncbi.nlm.nih.gov/gene/581 |
| Ensembl ID | ENSG00000087088 |
| UniProt ID | Q07812 |
| OMIM ID | 600040 |
| HGNC ID | 959 |
| Aliases | BCL2L4; BAX; BAX protein |
Description
The BAX gene encodes the BAX protein, a pro-apoptotic member of the BCL2 family. BAX plays a central role in the intrinsic (mitochondrial) apoptosis pathway. Upon apoptotic stimuli, BAX undergoes conformational changes, translocates to the mitochondrial outer membrane, and oligomerizes to form pores, leading to mitochondrial outer membrane permeabilization (MOMP), release of cytochrome c, and activation of caspases. BAX activity is tightly regulated by interactions with anti-apoptotic proteins (e.g., BCL2) and BH3-only proteins. Dysregulation of BAX expression or function contributes to various diseases, including cancer and neurodegenerative disorders.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Cancer (various types) | Loss of BAX function (e.g., frameshift mutations in microsatellite instability) reduces apoptosis, promoting tumorigenesis and resistance to therapy. | COSMIC; ClinVar; multiple studies |
| Colorectal cancer | Frameshift mutations in the (G)8 tract of BAX are common in microsatellite instability-high (MSI-H) tumors, leading to truncated inactive protein. | COSMIC; ClinVar |
| Lymphoma | BAX mutations or altered expression contribute to apoptosis resistance in B-cell lymphomas. | COSMIC; literature |
| Neurodegenerative diseases (e.g., Alzheimer's, Parkinson's) | Altered BAX expression or activity may contribute to neuronal apoptosis, though evidence is complex. | OMIM; literature |
| Autoimmune lymphoproliferative syndrome (ALPS) - rare | Germline BAX mutations have been reported in atypical ALPS, leading to defective apoptosis of lymphocytes. | OMIM; ClinVar |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Small intestine | 20.4 | High |
| Spleen | 18.2 | High |
| Bone marrow | 16.5 | High |
| Lymph node | 15.8 | High |
| Colon | 14.9 | High |
| Liver | 12.3 | Medium |
| Kidney | 11.0 | Medium |
| Brain | 8.5 | Medium |
| Heart | 6.2 | Low |
| Skeletal muscle | 4.1 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| K-562 (leukemia) | 18.5 | High expression |
| HeLa (cervical cancer) | 15.2 | High expression |
| A549 (lung cancer) | 12.8 | Medium expression |
| MCF7 (breast cancer) | 10.1 | Medium expression |
| HepG2 (liver cancer) | 9.3 | Medium expression |
| SH-SY5Y (neuroblastoma) | 7.8 | Low expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.121_122insA (p.Thr41fs) | Frameshift insertion | Common in MSI-H colorectal cancer | Truncated protein, loss of pro-apoptotic function |
| c.128G>A (p.Gly43Asp) | Missense | Rare in cancer | Impaired dimerization and reduced apoptosis |
| c.220C>T (p.Arg74Ter) | Nonsense | Rare in cancer | Premature stop, loss of function |
| c.376G>A (p.Gly126Ser) | Missense | Rare in cancer | Altered conformational change, reduced MOMP |
| c.512G>A (p.Arg171His) | Missense | Rare in cancer | Impaired oligomerization, dominant-negative effect |
Mutation functional classification
Loss of Function (LOF)
Most BAX mutations in cancer are loss-of-function, leading to reduced apoptosis and increased cell survival. Frameshift and nonsense mutations truncate the protein, while missense mutations may disrupt key functional domains.
Gain of Function (GOF)
No clear gain-of-function mutations have been reported for BAX; its role is primarily pro-apoptotic, and gain-of-function would likely increase apoptosis, which is not commonly selected for in cancer.
Dominant Negative (DN)
Some missense mutations (e.g., p.Arg171His) can act in a dominant-negative manner, interfering with wild-type BAX oligomerization and reducing apoptosis even in heterozygous state.
View complete mutation data：
Gene Ontology (GO)
| • apoptosis | • mitochondrial outer membrane permeabilization |
| • protein homodimerization activity | • protein heterodimerization activity |
| • BH3 domain binding | • channel activity |
| • cytochrome c release | • intrinsic apoptotic signaling pathway |
Pathways
• Intrinsic Apoptosis Pathway
• p53-dependent apoptosis
• BCL2 family-mediated regulation of apoptosis
• Mitochondrial outer membrane permeabilization (MOMP)
Protein Summary
The BAX protein (UniProt Q07812) is a 192-amino acid protein (21 kDa) that belongs to the BCL2 family. It contains a BH3 domain, a BH1 domain, and a C-terminal transmembrane domain. In healthy cells, BAX is predominantly cytosolic or loosely attached to mitochondria. Upon apoptotic stimuli, BAX undergoes conformational changes, exposing its BH3 domain and C-terminal tail, leading to mitochondrial targeting and insertion into the outer membrane. BAX then oligomerizes to form pores, causing MOMP and release of pro-apoptotic factors such as cytochrome c. BAX activity is regulated by anti-apoptotic proteins (e.g., BCL2, BCL-XL) and BH3-only proteins (e.g., BID, BIM).
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| BAX Knockout HEK293 Cell Line | EDJ-KQ1747 | Human | 581 | Details Get a Quote |
| BAX Knockout HCT 116 Cell Line | EDJ-KQ20266 | Human | 581 | Details Get a Quote |
| BAX Knockout A-549 Cell Line | EDJ-KQ21614 | Human | 581 | Details Get a Quote |
| BAX Knockout HeLa Cell Line | EDJ-KQ21616 | Human | 581 | Details Get a Quote |
| Bax and Bak1 Knockout ExpiCHO Cell Line | EDC90319 | Chinese hamster | 100689032 and 100689368 | Details Get a Quote |
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