CSN3: Kappa-Casein Gene
Key milk protein gene involved in coagulation and nutritional properties
Gene Information Card
| Symbol | CSN3 |
|---|---|
| Full Name | Casein Kappa |
| Gene Type | protein-coding |
| Chromosomal Location | 4q13.3 |
| NCBI Gene ID | 1448 ncbi.nlm.nih.gov/gene/1448 |
| Ensembl ID | ENSG00000171209 |
| UniProt ID | P07498 |
| OMIM ID | 601695 |
| HGNC ID | 2446 |
| Aliases | CASB, CASK, K-CASEIN, kappa-casein |
Description
The CSN3 gene encodes kappa-casein, a major milk protein that stabilizes casein micelles and is essential for milk coagulation. It is primarily expressed in mammary epithelial cells during lactation. Kappa-casein is cleaved by chymosin (rennin) during cheese production, releasing glycomacropeptide and para-kappa-casein. Genetic variants influence milk composition, coagulation properties, and may be associated with milk allergy or intolerance.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Milk allergy | Kappa-casein is a major allergen; specific IgE binding to epitopes triggers allergic response | ClinVar, literature |
| Casein intolerance | Variants in CSN3 may alter digestibility and immune reactivity | OMIM, literature |
| Lactation insufficiency | Rare variants affecting protein stability or secretion | ClinVar |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Mammary gland | High | High |
| Breast | High | High |
| Salivary gland | Low | Low |
| Skin | Not detected | Not detected |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| MCF-7 (breast cancer) | 0.0 | No expression |
| MDA-MB-231 (breast cancer) | 0.0 | No expression |
| Primary mammary epithelial cells | High | Lactation-specific expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.351C>T (p.Pro117Leu) | Missense | 0.1% (population) | Alters chymosin cleavage site; may affect coagulation |
| c.478G>A (p.Glu160Lys) | Missense | 0.05% | Associated with altered micelle stability |
| c.1A>G (p.Met1Val) | Start loss | Rare | Loss of protein expression |
Mutation functional classification
Loss of Function (LOF)
Start loss mutations (e.g., p.Met1Val) abolish protein production.
Gain of Function (GOF)
Not reported.
Dominant Negative (DN)
Not reported.
View complete mutation data：
Gene Ontology (GO)
Pathways
• KEGG: hsa04979 - Protein digestion and absorption
• Reactome: R-HSA-382551 - Transport of small molecules
• Reactome: R-HSA-6798695 - Neutrophil degranulation
Protein Summary
Kappa-casein is a 190-amino-acid secreted protein (UniProt P07498) that forms disulfide-linked polymers and stabilizes casein micelles. It is cleaved by chymosin between Phe105-Met106, releasing hydrophilic glycomacropeptide (C-terminal) and hydrophobic para-kappa-casein (N-terminal). The protein is heavily glycosylated and phosphorylated. It plays a critical role in milk coagulation and nutrient delivery.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| CSN3 Knockout HEK293 Cell Line | EDJ-KQ4365 | Human | 1448 | Details Get a Quote |
| CSN3 Knockout HeLa Cell Line | EDJ-KQ53010 | Human | 1448 | Details Get a Quote |
| CSN3 Knockout A-549 Cell Line | EDJ-KQ61476 | Human | 1448 | Details Get a Quote |
| CSN3 Knockout HCT 116 Cell Line | EDJ-KQ69973 | Human | 1448 | Details Get a Quote |
