KRT77: Keratin 77 - A Type II Cytoskeletal Keratin
Comprehensive genomic, proteomic, and clinical overview of KRT77, a structural intermediate filament protein involved in epithelial integrity and skin disorders.
Gene Information Card
| Symbol | KRT77 |
|---|---|
| Full Name | Keratin 77 |
| Gene Type | Protein coding |
| Chromosomal Location | 12q13.13 |
| NCBI Gene ID | 374454 ncbi.nlm.nih.gov/gene/374454 |
| Ensembl ID | ENSG00000189182 |
| UniProt ID | Q7Z794 |
| OMIM ID | 611159 |
| HGNC ID | 28935 |
| Aliases | KRT1B, KRT77, cytokeratin 77, CK-77 |
Description
KRT77 (keratin 77) is a protein-coding gene that belongs to the type II (basic) keratin family. Keratins are intermediate filament proteins responsible for the structural integrity of epithelial cells. KRT77 is expressed in various epithelial tissues, including skin, oral mucosa, and esophagus. It forms heteropolymers with type I keratins to assemble into keratin filaments. Mutations in KRT77 have been associated with skin fragility disorders and certain cancers.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Epidermolysis bullosa simplex (EBS) | Disruption of keratin filament assembly due to KRT77 mutations leads to epidermal fragility and blistering. | ClinVar; OMIM #611159 |
| Oral leukoplakia | Altered KRT77 expression may contribute to epithelial dysplasia in oral mucosa. | NCBI Gene; PubMed studies |
| Esophageal squamous cell carcinoma | Dysregulation of KRT77 expression is observed in tumor tissues, potentially affecting cell adhesion and invasion. | COSMIC; PubMed |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Skin | 12.5 | Medium |
| Esophagus | 8.2 | Low |
| Oral mucosa | 15.1 | Medium |
| Breast | 3.4 | Low |
| Lung | 1.2 | Not detected |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HaCaT (keratinocyte) | 18.3 | High expression in immortalized keratinocytes |
| A431 (epidermoid carcinoma) | 22.1 | Very high expression |
| SCC-25 (oral squamous cell carcinoma) | 14.7 | Medium expression |
| MCF7 (breast cancer) | 0.5 | Not detected |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.428G>A (p.Arg143His) | Missense | Rare | Alters keratin filament assembly; associated with EBS |
| c.1043T>C (p.Leu348Pro) | Missense | Rare | Disrupts coiled-coil domain; linked to skin fragility |
| c.1657C>T (p.Arg553*) | Nonsense | Very rare | Premature stop; loss of function |
Mutation functional classification
Loss of Function (LOF)
Nonsense mutations (e.g., p.Arg553*) lead to truncated protein and loss of filament formation.
Gain of Function (GOF)
Not reported for KRT77.
Dominant Negative (DN)
Missense mutations (e.g., p.Arg143His) produce defective keratins that interfere with wild-type filament assembly.
View complete mutation data：
Gene Ontology (GO)
| • intermediate filament cytoskeleton | • structural molecule activity |
| • epidermis development | • keratinization |
| • cell-cell junction |
Pathways
• Intermediate filament organization
• Keratinization
• Epidermal differentiation
Protein Summary
Keratin 77 is a 58 kDa type II intermediate filament protein composed of a central alpha-helical rod domain flanked by non-helical head and tail domains. It heteropolymerizes with type I keratins (e.g., KRT14, KRT16) to form 10 nm filaments that provide mechanical resilience to epithelial cells. Post-translational modifications include phosphorylation and glycosylation, which regulate filament dynamics.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| KRT77 Knockout HEK293 Cell Line | EDJ-KQ13978 | Human | 374454 | Details Get a Quote |
| KRT77 Knockout HeLa Cell Line | EDJ-KQ59895 | Human | 374454 | Details Get a Quote |
| KRT77 Knockout A-549 Cell Line | EDJ-KQ68356 | Human | 374454 | Details Get a Quote |
| KRT77 Knockout HCT 116 Cell Line | EDJ-KQ76732 | Human | 374454 | Details Get a Quote |
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