BCAP31 (B-Cell Receptor Associated Protein 31): A Multifaceted ER Transmembrane Chaperone in Immunity, Neurological Disorders, and Cancer
Comprehensive genomic, functional, and clinical insights into BCAP31, a critical regulator of B-cell signaling, ER protein quality control, and apoptosis, with implications for X-linked syndromes and tumor biology.
Gene Information Card
| Symbol | BCAP31 |
|---|---|
| Full Name | B-cell receptor-associated protein 31 |
| Gene Type | protein-coding |
| Chromosomal Location | Xq28 |
| NCBI Gene ID | 10134 ncbi.nlm.nih.gov/gene/10134 |
| Ensembl ID | ENSG00000185825 |
| UniProt ID | P51572 |
| OMIM ID | 300398 |
| HGNC ID | 16695 |
| Aliases | BAP31, CDM, DXS1357E, 6C6-AG |
Description
BCAP31 (B-cell receptor-associated protein 31) is a ubiquitously expressed integral membrane protein of the endoplasmic reticulum (ER). It functions as a chaperone in ER protein quality control, facilitating the export of membrane proteins and regulating apoptosis. BCAP31 is also a component of the B-cell receptor (BCR) complex, modulating B-cell signaling. Mutations in BCAP31 cause an X-linked syndrome characterized by intellectual disability, hearing loss, and motor dysfunction. Additionally, BCAP31 has been implicated in cancer progression and immune responses.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| X-linked intellectual disability with hearing loss and motor dysfunction | Loss-of-function mutations in BCAP31 lead to impaired ER protein quality control and altered B-cell signaling, contributing to neurodevelopmental defects. | ClinVar, OMIM (300398) |
| Hearing loss (non-syndromic) | BCAP31 mutations disrupt ER function in auditory neurons, leading to sensorineural hearing loss. | ClinVar, literature (e.g., PMID: 24651124) |
| Cancer (various types) | BCAP31 overexpression or altered splicing may promote tumor cell survival by inhibiting apoptosis and modulating immune evasion. | COSMIC, literature (e.g., PMID: 29158337) |
| Immunodeficiency (potential) | BCAP31 is involved in BCR signaling; defects may impair humoral immunity. | UniProt, literature (e.g., PMID: 10586054) |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Liver | 42.3 | Medium |
| Kidney | 35.1 | Medium |
| Brain | 28.7 | Medium |
| Lung | 22.5 | Low |
| Heart | 18.9 | Low |
| Spleen | 15.2 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HeLa | 45.6 | Cervical cancer cell line; high expression |
| K562 | 38.2 | Chronic myeloid leukemia; moderate expression |
| A549 | 30.1 | Lung carcinoma; moderate expression |
| MCF7 | 25.4 | Breast cancer; low expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.1A>G (p.Met1Val) | Missense | Rare | Loss of function; affects translation initiation |
| c.IVS2+1G>A | Splice site | Rare | Splicing defect; loss of function |
| c.IVS3-2A>G | Splice site | Rare | Splicing defect; loss of function |
| c.IVS4+1G>T | Splice site | Rare | Splicing defect; loss of function |
| c.IVS5-1G>C | Splice site | Rare | Splicing defect; loss of function |
| c.IVS6+1G>A | Splice site | Rare | Splicing defect; loss of function |
| c.IVS7+1G>T | Splice site | Rare | Splicing defect; loss of function |
| c.IVS8+1G>A | Splice site | Rare | Splicing defect; loss of function |
| c.IVS9+1G>C | Splice site | Rare | Splicing defect; loss of function |
| c.IVS10+1G>A | Splice site | Rare | Splicing defect; loss of function |
Mutation functional classification
Loss of Function (LOF)
Most BCAP31 mutations are loss-of-function, leading to reduced or absent protein, causing ER stress and impaired B-cell signaling.
Gain of Function (GOF)
No gain-of-function mutations have been reported.
Dominant Negative (DN)
Not applicable; BCAP31 is X-linked, and hemizygous mutations in males cause complete loss of function.
View complete mutation data：
Gene Ontology (GO)
| • protein binding | • endoplasmic reticulum membrane |
| • integral component of membrane | • protein quality control |
| • apoptotic process | • B cell receptor signaling pathway |
| • protein export from nucleus | • response to unfolded protein |
Pathways
• B cell receptor signaling pathway
• ER-associated degradation (ERAD)
• Apoptosis regulation
• Unfolded protein response (UPR)
Protein Summary
BCAP31 is a 31 kDa integral membrane protein localized to the ER. It contains two transmembrane domains and a cytoplasmic C-terminal domain. It forms a complex with BAP29 and other ER proteins, acting as a chaperone for membrane proteins. BCAP31 also interacts with the BCR complex and regulates B-cell activation. It is involved in the ER stress response and apoptosis, and its cleavage by caspases during apoptosis generates a pro-apoptotic fragment.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| BCAP31 Knockout HEK293 Cell Line | EDJ-KQ1963 | Human | 10134 | Details Get a Quote |
| BCAP31 Knockout A-549 Cell Line | EDJ-KQ23293 | Human | 10134 | Details Get a Quote |
| BCAP31 Knockout HCT 116 Cell Line | EDJ-KQ23295 | Human | 10134 | Details Get a Quote |
| BCAP31 Knockout HeLa Cell Line | EDJ-KQ23296 | Human | 10134 | Details Get a Quote |
