KRTAP4-5 (Keratin Associated Protein 4-5): Genetics, Expression, and Disease Relevance
A comprehensive biomedical overview of the KRTAP4-5 gene, including genomic context, expression patterns, and clinical associations.
Gene Information Card
| Symbol | KRTAP4-5 |
|---|---|
| Full Name | Keratin Associated Protein 4-5 |
| Gene Type | protein coding |
| Chromosomal Location | 17q21.2 |
| NCBI Gene ID | 83895 ncbi.nlm.nih.gov/gene/83895 |
| Ensembl ID | ENSG00000206183 |
| UniProt ID | Q9BYR8 |
| OMIM ID | 611289 |
| HGNC ID | 18937 |
| Aliases | KAP4.5, KRTAP4.5 |
Description
KRTAP4-5 encodes a keratin-associated protein (KAP) that is a component of the hair fiber. KAPs are structural proteins that cross-link with keratin intermediate filaments to provide strength and rigidity to hair. KRTAP4-5 belongs to the high-sulfur KAP family and is expressed primarily in the hair cortex. Its expression is regulated during hair follicle differentiation. While its exact role in disease is not fully established, variations in KAP genes have been associated with hair shaft disorders and may influence hair properties.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Woolly hair | Potential involvement in hair shaft structure; mutations may disrupt keratin cross-linking. | Limited evidence; inferred from KAP family function. |
| Hair morphology traits | Genetic variation may affect hair texture and strength. | GWAS and candidate gene studies suggest association. |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Skin | Not detected | Low |
| Hair follicle | Not available | High (based on RNA-seq in hair-related tissues) |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| Keratinocytes | Not detected | No expression in standard cell lines |
| Hair follicle dermal papilla cells | Not available | Expected expression based on tissue specificity |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| rs201183495 | SNV | 0.1% (global) | Missense variant; functional impact unknown |
| rs147901577 | SNV | 0.05% | Synonymous variant; no known effect |
Mutation functional classification
Loss of Function (LOF)
No confirmed loss-of-function mutations reported in KRTAP4-5.
Gain of Function (GOF)
No evidence of gain-of-function mutations.
Dominant Negative (DN)
Not applicable; no dominant-negative mechanisms described.
View complete mutation data：
Gene Ontology (GO)
| • structural constituent of skin epidermis | • keratin filament binding |
| • hair follicle development |
Pathways
• Keratinization
• Formation of the cornified envelope
Protein Summary
KRTAP4-5 is a small, cysteine-rich protein (approximately 150 amino acids) that belongs to the high-sulfur keratin-associated protein family. It is synthesized in the hair cortex and cross-links with keratin intermediate filaments via disulfide bonds, contributing to the mechanical strength and rigidity of hair. The protein contains a characteristic cysteine-rich repeat domain. Its expression is tightly regulated during hair follicle differentiation, and it is not expressed in other tissues at significant levels.
Related Services
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|---|---|---|---|---|
| No Data | ||||
