KRT84: Keratin 84
A type II hair keratin expressed in the hair follicle cortex.
Gene Information Card
| Symbol | KRT84 |
|---|---|
| Full Name | keratin 84 |
| Gene Type | protein-coding |
| Chromosomal Location | 12q13.13 |
| NCBI Gene ID | 3890 ncbi.nlm.nih.gov/gene/3890 |
| Ensembl ID | ENSG00000161846 |
| UniProt ID | Q9NSB2 |
| OMIM ID | 602766 |
| HGNC ID | 6443 |
| Aliases | KRT2-17, KRT84, HB4, K84, KRTHB4 |
Description
KRT84 (keratin 84) is a protein-coding gene that belongs to the type II keratin family. It encodes a basic hair keratin specifically expressed in the cortex of the hair follicle. Keratin 84 heteropolymerizes with type I hair keratins to form intermediate filaments, providing mechanical strength and structural integrity to the hair shaft. Mutations in KRT84 are associated with hair disorders such as monilethrix.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Monilethrix | Missense mutations in the helix initiation motif disrupt keratin filament assembly, leading to fragile, beaded hair. | ClinVar; OMIM #158000 |
| Woolly hair (isolated) | Rare variants may alter hair shaft structure, but direct evidence is limited. | ClinVar; PubMed |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Hair follicle (cortex) | High | Tissue-specific |
| Skin | Low | GTEx |
| Esophagus | Very low | GTEx |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HaCaT (keratinocyte) | 0.0 | Not expressed |
| NHEK (normal human epidermal keratinocytes) | 0.0 | Not expressed |
| Hair follicle dermal papilla cells | 0.0 | Not expressed |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.377T>C (p.Leu126Pro) | Missense | Rare | Disrupts helix initiation motif; associated with monilethrix |
| c.374A>G (p.Asn125Ser) | Missense | Rare | Alters filament assembly; reported in monilethrix |
| c.367C>T (p.Arg123Cys) | Missense | Rare | Likely pathogenic; disrupts coiled-coil domain |
Mutation functional classification
Loss of Function (LOF)
Not established; missense mutations likely cause dominant-negative effects.
Gain of Function (GOF)
Not reported.
Dominant Negative (DN)
Missense mutations in the helix initiation motif act in a dominant-negative manner, impairing filament formation.
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) |
Pathways
• Intermediate filament organization (Reactome: R-HSA-6809371)
• Keratinization (Reactome: R-HSA-6805567)
Protein Summary
Keratin 84 is a 58.5 kDa type II hair keratin composed of a central alpha-helical rod domain flanked by non-helical head and tail domains. It forms heterodimers with type I hair keratins (e.g., KRT31, KRT35) and assembles into 10 nm intermediate filaments. The protein is essential for the mechanical resilience of the hair cortex. Mutations in the conserved helix initiation motif cause monilethrix, characterized by brittle, beaded hair.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| KRT84 Knockout HEK293 Cell Line | EDJ-KQ5107 | Human | 3890 | Details Get a Quote |
| KRT84 Knockout HeLa Cell Line | EDJ-KQ53769 | Human | 3890 | Details Get a Quote |
| KRT84 Knockout A-549 Cell Line | EDJ-KQ62247 | Human | 3890 | Details Get a Quote |
| KRT84 Knockout HCT 116 Cell Line | EDJ-KQ70732 | Human | 3890 | Details Get a Quote |
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