KRT33B
Keratin 33B, a type I hair keratin gene involved in hair shaft formation
Gene Information Card
| Symbol | KRT33B |
|---|---|
| Full Name | keratin 33B |
| Gene Type | protein-coding |
| Chromosomal Location | 17q21.2 |
| NCBI Gene ID | 3884 ncbi.nlm.nih.gov/gene/3884 |
| Ensembl ID | ENSG00000131737 |
| UniProt ID | Q14525 |
| OMIM ID | 602766 |
| HGNC ID | 6443 |
| Aliases | KRT33B, Ha-3II, KRT33B, hHa3-II, keratin 33B, type I hair keratin 3B |
Description
KRT33B (keratin 33B) is a protein-coding gene located on chromosome 17q21.2. It encodes a type I hair keratin, specifically keratin 33B (also known as Ha-3II or hHa3-II), which is a basic (type I) intermediate filament protein. This keratin is expressed in the hair cortex and contributes to the structural integrity of hair shafts. Mutations in KRT33B are associated with hair disorders, including monilethrix.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Monilethrix | Mutations in KRT33B disrupt keratin intermediate filament assembly in the hair cortex, leading to fragile, beaded hair shafts. | PMID: 10980576; OMIM #158000 |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Hair follicle | Not available | High |
| Skin | Not available | Moderate |
| Scalp | Not available | High |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HaCaT (keratinocyte) | Not available | Low |
| NHEK (normal human epidermal keratinocytes) | Not available | Low |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.367C>T (p.Arg123Cys) | Missense | Rare | Disrupts keratin filament formation; associated with monilethrix |
| c.368G>A (p.Arg123His) | Missense | Rare | Similar effect; reported in monilethrix families |
Mutation functional classification
Loss of Function (LOF)
Missense mutations in the helix initiation motif impair filament assembly, leading to structural weakness.
Gain of Function (GOF)
Not reported.
Dominant Negative (DN)
Mutant keratin 33B interferes with wild-type keratin filament polymerization, causing dominant-negative effects.
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) |
Pathways
• Intermediate filament organization (Reactome: R-HSA-6809371)
• Keratinization (Reactome: R-HSA-6805567)
Protein Summary
Keratin 33B is a type I hair keratin (basic) that heteropolymerizes with type II hair keratins to form intermediate filaments in the hair cortex. It is essential for hair shaft strength and integrity. The protein contains a central alpha-helical rod domain with conserved helix initiation and termination motifs critical for filament assembly.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| KRT33B Knockout HEK293 Cell Line | EDJ-KQ50413 | Human | 3884 | Details Get a Quote |
| KRT33B Knockout HeLa Cell Line | EDJ-KQ53764 | Human | 3884 | Details Get a Quote |
| KRT33B Knockout A-549 Cell Line | EDJ-KQ62243 | Human | 3884 | Details Get a Quote |
| KRT33B Knockout HCT 116 Cell Line | EDJ-KQ70727 | Human | 3884 | Details Get a Quote |
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