KRT12: Keratin 12 Gene in Corneal Epithelial Integrity
Essential intermediate filament protein for corneal transparency and Meesmann corneal dystrophy
Gene Information Card
| Symbol | KRT12 |
|---|---|
| Full Name | Keratin 12 |
| Gene Type | protein-coding |
| Chromosomal Location | 17q21.2 |
| NCBI Gene ID | 3859 ncbi.nlm.nih.gov/gene/3859 |
| Ensembl ID | ENSG00000187242 |
| UniProt ID | Q99456 |
| OMIM ID | 601687 |
| HGNC ID | 6415 |
| Aliases | K12, CK12, KRT12A, KRT12B |
Description
KRT12 encodes keratin 12, a type I intermediate filament protein specifically expressed in the corneal epithelium. Keratin 12 pairs with keratin 3 (KRT3) to form heterodimers that assemble into intermediate filaments, providing mechanical stability and maintaining corneal epithelial integrity. Mutations in KRT12 are associated with Meesmann corneal dystrophy, an autosomal dominant disorder characterized by fragility of the anterior corneal epithelium and recurrent erosions.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Meesmann corneal dystrophy | Dominant-negative mutations in KRT12 disrupt keratin filament assembly in corneal epithelial cells, leading to cytoplasmic vacuolization and epithelial fragility. | ClinVar, OMIM |
| Corneal epithelial basement membrane dystrophy | Altered keratin network integrity compromises cell adhesion and basement membrane attachment. | NCBI Gene, OMIM |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Cornea | High (nTPM: 1000+) | Tissue-specific high expression |
| Esophagus | Low (nTPM: 5) | Minimal expression |
| Skin | Not detected | No significant expression |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| Corneal epithelial cells (HCE-T) | High | Primary expression site |
| HeLa | Not detected | No expression |
| A549 | Not detected | No expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.427G>A (p.Val143Met) | Missense | Common in Meesmann dystrophy | Disrupts filament assembly |
| c.428T>C (p.Leu143Pro) | Missense | Rare | Dominant-negative effect |
| c.1309C>T (p.Arg437Cys) | Missense | Reported | Alters keratin dimerization |
Mutation functional classification
Loss of Function (LOF)
Not reported; KRT12 loss-of-function is not associated with disease phenotype.
Gain of Function (GOF)
Not reported.
Dominant Negative (DN)
Most pathogenic mutations (e.g., Val143Met, Leu143Pro) act via dominant-negative interference with wild-type keratin 12 and keratin 3 filament assembly.
View complete mutation data：
Gene Ontology (GO)
| • structural molecule activity (GO:0005198) | • intermediate filament (GO:0005882) |
| • keratin filament (GO:0045095) | • epithelial cell differentiation (GO:0030855) |
| • corneal epithelial cell differentiation (GO:0008546) |
Pathways
• Intermediate filament organization (Reactome: R-HSA-6809371)
• Keratinization (Reactome: R-HSA-6805567)
Protein Summary
Keratin 12 is a 55 kDa type I intermediate filament protein (494 amino acids) with a central alpha-helical rod domain flanked by non-helical head and tail domains. It heteropolymerizes with keratin 3 to form corneal epithelial intermediate filaments, essential for corneal transparency and resistance to mechanical stress. The protein is highly conserved among mammals and is exclusively expressed in differentiated corneal epithelial cells.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| KRT12 Knockout HEK293 Cell Line | EDJ-KQ5089 | Human | 3859 | Details Get a Quote |
| KRT12 Knockout HeLa Cell Line | EDJ-KQ53758 | Human | 3859 | Details Get a Quote |
| KRT12 Knockout A-549 Cell Line | EDJ-KQ62235 | Human | 3859 | Details Get a Quote |
| KRT12 Knockout HCT 116 Cell Line | EDJ-KQ70720 | Human | 3859 | Details Get a Quote |
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