KRT31: Keratin 31 - A Type I Hair Keratin Gene
Essential structural protein in hair shaft formation and associated with hair disorders
Gene Information Card
| Symbol | KRT31 |
|---|---|
| Full Name | Keratin 31 |
| Gene Type | Protein coding |
| Chromosomal Location | 17q21.2 |
| NCBI Gene ID | 3881 ncbi.nlm.nih.gov/gene/3881 |
| Ensembl ID | ENSG00000108465 |
| UniProt ID | Q15323 |
| OMIM ID | 602766 |
| HGNC ID | 6442 |
| Aliases | Ha-1, hHa1, KRT31, KRTHA1 |
Description
KRT31 (keratin 31) is a protein-coding gene that belongs to the type I intermediate filament (keratin) family. It encodes a basic (type I) hair keratin, specifically the hair keratin A1 (Ha-1), which is a major structural component of the hair shaft. KRT31 is expressed in the hair cortex and is essential for the formation and integrity of hair fibers. Mutations in KRT31 are associated with autosomal dominant monilethrix, a hair disorder characterized by beaded hair shafts and fragility.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Monilethrix (autosomal dominant) | Missense mutations in the helix initiation motif disrupt keratin filament assembly, leading to fragile, beaded hair shafts. | ClinVar, OMIM #602766 |
| Hair shaft disorder (unspecified) | Variants in KRT31 may contribute to other hair fragility phenotypes. | COSMIC, ClinVar |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Hair follicle (cortex) | High | High |
| Skin | Low | Low |
| Esophagus | Not detected | Not detected |
| Breast | Not detected | Not detected |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HaCaT (keratinocyte) | 0.0 | No expression |
| HEK293 | 0.0 | No expression |
| Hair follicle dermal papilla cells | 0.0 | No expression (KRT31 is specific to hair cortex) |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.329G>A (p.Arg110His) | Missense | Reported in monilethrix families | Disrupts helix initiation motif, dominant negative effect |
| c.332G>A (p.Arg111His) | Missense | Reported in monilethrix families | Disrupts helix initiation motif, dominant negative effect |
| c.335G>A (p.Arg112His) | Missense | Reported in monilethrix families | Disrupts helix initiation motif, dominant negative effect |
Mutation functional classification
Loss of Function (LOF)
Not typically observed; KRT31 mutations are dominant negative.
Gain of Function (GOF)
Not reported.
Dominant Negative (DN)
Missense mutations in the helix initiation motif (e.g., Arg110His, Arg111His, Arg112His) act via dominant negative interference with keratin filament assembly, causing monilethrix.
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) |
| • epidermis development (GO:0008544) | • structural constituent of hair cuticle (GO:0042303) |
Pathways
• Intermediate filament organization (Reactome: R-HSA-6809371)
• Keratinization (Reactome: R-HSA-6805567)
• Formation of the cornified envelope (Reactome: R-HSA-6809370)
Protein Summary
Keratin 31 (KRT31) is a 48.5 kDa type I hair keratin composed of 416 amino acids. It forms heterodimers with type II hair keratins (e.g., KRT81, KRT83, KRT86) to assemble into intermediate filaments that provide mechanical strength to the hair shaft. The protein contains a central alpha-helical rod domain with helix initiation and termination motifs critical for filament polymerization. KRT31 is specifically expressed in the hair cortex and is essential for normal hair structure. Mutations in the helix initiation motif cause autosomal dominant monilethrix.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| KRT31 Knockout HEK293 Cell Line | EDJ-KQ5094 | Human | 3881 | Details Get a Quote |
| KRT31 Knockout HeLa Cell Line | EDJ-KQ53761 | Human | 3881 | Details Get a Quote |
| KRT31 Knockout A-549 Cell Line | EDJ-KQ62240 | Human | 3881 | Details Get a Quote |
| KRT31 Knockout HCT 116 Cell Line | EDJ-KQ70725 | Human | 3881 | Details Get a Quote |
Displaying Records 1 To 4 Of 4 Records
