KRT33A
Keratin 33A, a type I hair keratin involved in hair shaft formation
Gene Information Card
| Symbol | KRT33A |
|---|---|
| Full Name | keratin 33A |
| Gene Type | protein-coding |
| Chromosomal Location | 17q21.2 |
| NCBI Gene ID | 3883 ncbi.nlm.nih.gov/gene/3883 |
| Ensembl ID | ENSG00000108423 |
| UniProt ID | O76009 |
| OMIM ID | 602760 |
| HGNC ID | 6443 |
| Aliases | Ha-3I, K33A, KRTHA3A, hHa3-I |
Description
KRT33A encodes a type I hair keratin (keratin 33A) that heterodimerizes with type II keratins to form intermediate filaments in the hair shaft. It is specifically expressed in the hair cortex and contributes to hair fiber strength and structure. Mutations in KRT33A are associated with autosomal dominant monilethrix, a condition characterized by beaded hair and fragility.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Monilethrix | Missense mutations in the helix initiation motif disrupt keratin filament assembly, leading to hair shaft fragility and beaded appearance. | ClinVar, OMIM |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Skin (scalp) | 0.0 | Not detected |
| Hair follicle | High | High |
| Esophagus | 0.0 | Not detected |
| Cervix | 0.0 | Not detected |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HaCaT (keratinocyte) | 0.0 | Not expressed |
| Hair follicle dermal papilla cells | 0.0 | Not expressed |
| Hair follicle matrix cells | High | High expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.367G>A (p.Glu123Lys) | Missense | Rare | Disrupts helix initiation motif; associated with monilethrix |
| c.365A>G (p.Asn122Ser) | Missense | Rare | Alters filament assembly; pathogenic in monilethrix |
Mutation functional classification
Loss of Function (LOF)
Not established; missense mutations likely exert dominant-negative effects rather than complete loss.
Gain of Function (GOF)
Not reported.
Dominant Negative (DN)
Yes; mutant keratin 33A interferes with wild-type keratin filament formation in hair cortex.
View complete mutation data：
Gene Ontology (GO)
| • structural constituent of skin epidermis | • intermediate filament organization |
| • hair follicle development | • keratin filament |
Pathways
• Keratinization
• Formation of the cornified envelope
• Intermediate filament polymerization
Protein Summary
Keratin 33A (UniProt O76009) is a 416-amino acid type I hair keratin with a central alpha-helical rod domain flanked by non-helical head and tail regions. It forms heterodimers with type II hair keratins (e.g., KRT85) to build intermediate filaments essential for hair shaft integrity. The protein is expressed specifically in the hair cortex and is absent in other epithelial tissues.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| KRT33A Knockout HEK293 Cell Line | EDJ-KQ5096 | Human | 3883 | Details Get a Quote |
| KRT33A Knockout HeLa Cell Line | EDJ-KQ53763 | Human | 3883 | Details Get a Quote |
| KRT33A Knockout A-549 Cell Line | EDJ-KQ62242 | Human | 3883 | Details Get a Quote |
| KRT33A Knockout HCT 116 Cell Line | EDJ-KQ70726 | Human | 3883 | Details Get a Quote |
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