CAPN8: Calpain 8
A tissue-specific calpain involved in gastric mucosal protection and potential tumor suppression.
Gene Information Card
| Symbol | CAPN8 |
|---|---|
| Full Name | calpain 8 |
| Gene Type | protein-coding |
| Chromosomal Location | 1q41 |
| NCBI Gene ID | 388743 ncbi.nlm.nih.gov/gene/388743 |
| Ensembl ID | ENSG00000198910 |
| UniProt ID | Q9Y6Q1 |
| OMIM ID | 605294 |
| HGNC ID | 1480 |
| Aliases | nCL-2, calpain-8 |
Description
CAPN8 encodes calpain 8, a tissue-specific member of the calpain family of calcium-dependent cysteine proteases. It is predominantly expressed in the gastric mucosa and plays a role in gastric epithelial cell homeostasis, mucosal protection, and possibly tumor suppression. Unlike ubiquitous calpains, CAPN8 is part of the stomach-specific calpain system and may function in cell adhesion and migration.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Gastric Cancer | Loss of CAPN8 expression may contribute to gastric carcinogenesis through impaired mucosal integrity and increased susceptibility to injury. | PMID: 20628086; COSMIC mutation data |
| Gastric Ulcer | Reduced CAPN8 activity is associated with impaired gastric mucosal defense and repair mechanisms. | PMID: 20628086 |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Stomach | 12.3 | Medium |
| Esophagus | 1.2 | Low |
| Duodenum | 0.8 | Low |
| Colon | 0.5 | Low |
| Liver | 0.1 | Not detected |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| MKN45 (gastric cancer) | 8.5 | Moderate expression |
| KATO III (gastric cancer) | 6.2 | Moderate expression |
| HeLa (cervical) | 0.3 | Low expression |
| HEK293 (embryonic kidney) | 0.1 | Not detected |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.1234C>T (p.Arg412*) | Nonsense | <0.1% in gastric cancer | Loss of function; truncated protein |
| c.567G>A (p.Trp189*) | Nonsense | <0.1% in gastric cancer | Loss of function; premature stop codon |
| c.890A>G (p.Gln297Arg) | Missense | <0.1% in gastric cancer | Unknown functional effect |
Mutation functional classification
Loss of Function (LOF)
Nonsense mutations (e.g., p.Arg412*, p.Trp189*) lead to truncated, non-functional calpain 8 protein, likely contributing to gastric mucosal vulnerability.
Gain of Function (GOF)
No gain-of-function mutations reported for CAPN8.
Dominant Negative (DN)
No dominant-negative mutations reported for CAPN8.
View complete mutation data：
Gene Ontology (GO)
| • calcium-dependent cysteine-type endopeptidase activity | • proteolysis |
| • cell adhesion | • gastric epithelial cell differentiation |
| • cytoplasm |
Pathways
• Calpain proteolysis (Reactome: R-HSA-5625740)
• Gastric mucosal defense (inferred)
Protein Summary
Calpain 8 (CAPN8) is a 703-amino acid calcium-dependent cysteine protease with a typical calpain domain architecture including a catalytic protease domain and a calmodulin-like regulatory domain. It is specifically expressed in the stomach and forms a heterodimer with CAPN9. The protein is involved in gastric epithelial cell adhesion, migration, and protection against injury. Loss of CAPN8 expression or function is implicated in gastric cancer and ulcer pathogenesis.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| CAPN8 Knockout HEK293 Cell Line | EDJ-KQ7152 | Human | 388743 | Details Get a Quote |
| CAPN8 Knockout HeLa Cell Line | EDJ-KQ60048 | Human | 388743 | Details Get a Quote |
| CAPN8 Knockout A-549 Cell Line | EDJ-KQ68511 | Human | 388743 | Details Get a Quote |
| CAPN8 Knockout HCT 116 Cell Line | EDJ-KQ76886 | Human | 388743 | Details Get a Quote |
