CALB2 (Calbindin 2) Gene: Structure, Function, and Clinical Significance
Comprehensive biomedical overview of the CALB2 gene encoding calretinin, a calcium-binding protein involved in neuronal function and cancer diagnostics.
Gene Information Card
| Symbol | CALB2 |
|---|---|
| Full Name | calbindin 2 |
| Gene Type | protein-coding |
| Chromosomal Location | 16q22.2 |
| NCBI Gene ID | 794 ncbi.nlm.nih.gov/gene/794 |
| Ensembl ID | ENSG00000102962 |
| UniProt ID | P22676 |
| OMIM ID | 114150 |
| HGNC ID | 1385 |
| Aliases | CAL2, CAB29, calretinin |
Description
CALB2 (calbindin 2) encodes calretinin, a 29 kDa calcium-binding protein belonging to the troponin C superfamily. Calretinin is expressed predominantly in neurons of the central and peripheral nervous systems, where it buffers intracellular calcium and modulates neuronal excitability. It is also expressed in certain epithelial and mesothelial cells. CALB2 is a well-established immunohistochemical marker for mesothelioma and is implicated in colorectal cancer, neuroblastoma, and other malignancies. The gene spans approximately 10 kb on chromosome 16q22.2 and contains 11 exons.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Malignant mesothelioma | CALB2 (calretinin) is a sensitive and specific immunohistochemical marker for mesothelioma; overexpression in mesothelial cells aids diagnosis. | ClinVar, NCBI PubMed |
| Colorectal cancer | CALB2 expression is frequently downregulated in colorectal adenocarcinomas; loss of calretinin may contribute to tumor progression. | COSMIC, NCBI PubMed |
| Neuroblastoma | Calretinin expression is associated with favorable histology and differentiation in neuroblastoma tumors. | NCBI PubMed |
| Epithelial ovarian cancer | Calretinin is used in differential diagnosis of ovarian sex cord-stromal tumors versus epithelial ovarian carcinomas. | ClinVar, NCBI PubMed |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Brain (cerebral cortex) | 12.5 | Medium |
| Cerebellum | 45.2 | High |
| Testis | 3.1 | Low |
| Colon | 1.8 | Low |
| Lung | 0.9 | Not detected |
| Heart | 0.5 | Not detected |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| NTERA-2 (embryonal carcinoma) | 28.3 | High expression |
| SH-SY5Y (neuroblastoma) | 15.7 | Moderate expression |
| MCF7 (breast cancer) | 2.1 | Low expression |
| HeLa (cervical cancer) | 1.4 | Low expression |
| A549 (lung cancer) | 0.3 | Not detected |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.1A>G (p.Met1?) | missense | <0.1% | Likely loss of start codon; predicted loss of function |
| c.295C>T (p.Arg99Trp) | missense | <0.1% | Substitution in EF-hand domain; may alter calcium binding |
| c.556G>A (p.Gly186Ser) | missense | <0.1% | Located in second EF-hand; uncertain significance |
Mutation functional classification
Loss of Function (LOF)
Mutations disrupting the start codon or EF-hand calcium-binding domains are predicted to impair calretinin's calcium buffering capacity.
Gain of Function (GOF)
No gain-of-function mutations have been reported for CALB2.
Dominant Negative (DN)
No dominant-negative mutations have been characterized for CALB2.
View complete mutation data：
Gene Ontology (GO)
Pathways
• Calcium signaling pathway (KEGG: hsa04020)
• Alzheimer disease – presenilin pathway (Reactome: R-HSA-8863720)
• Neurotransmitter release cycle (Reactome: R-HSA-112310)
Protein Summary
Calretinin (UniProt P22676) is a 271-amino acid protein with six EF-hand calcium-binding domains. It functions as a cytosolic calcium buffer and sensor, modulating calcium-dependent signaling in neurons. Calretinin is highly expressed in cerebellar granule cells, sensory neurons, and mesothelial cells. Its molecular weight is approximately 29 kDa. The protein exists as a monomer and can homodimerize. Post-translational modifications include N-terminal acetylation. Calretinin is widely used as a diagnostic immunohistochemical marker for mesothelioma and is also expressed in sex cord-stromal tumors of the ovary.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| CALB2 Knockout HEK293 Cell Line | EDJ-KQ2467 | Human | 794 | Details Get a Quote |
| CALB2 Knockout A-549 Cell Line | EDJ-KQ23019 | Human | 794 | Details Get a Quote |
| CALB2 Knockout HCT 116 Cell Line | EDJ-KQ23020 | Human | 794 | Details Get a Quote |
| CALB2 Knockout HeLa Cell Line | EDJ-KQ52777 | Human | 794 | Details Get a Quote |
Displaying Records 1 To 4 Of 4 Records
