SPRR4 Gene - Small Proline Rich Protein 4
A member of the cornified envelope precursor family involved in epidermal differentiation and barrier function.
Gene Information Card
| Symbol | SPRR4 |
|---|---|
| Full Name | Small Proline Rich Protein 4 |
| Gene Type | Protein coding |
| Chromosomal Location | 1q21.3 |
| NCBI Gene ID | 163778 ncbi.nlm.nih.gov/gene/163778 |
| Ensembl ID | ENSG00000163349 |
| UniProt ID | Q9BTE6 |
| OMIM ID | 618124 |
| HGNC ID | 23678 |
| Aliases | SPRR4A, SPRR4B |
Description
SPRR4 (Small Proline Rich Protein 4) is a protein-coding gene located on chromosome 1q21.3 within the epidermal differentiation complex (EDC). It encodes a member of the small proline-rich protein family, which are components of the cornified cell envelope in stratified squamous epithelia. SPRR4 is involved in cross-linking during terminal differentiation of keratinocytes, contributing to skin barrier integrity. Expression is predominantly in the epidermis and oral mucosa.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Psoriasis | Altered SPRR4 expression may disrupt cornified envelope formation, contributing to epidermal hyperplasia and barrier dysfunction. | NCBI Gene, OMIM |
| Atopic dermatitis | Reduced SPRR4 levels may impair skin barrier function, increasing susceptibility to allergens and pathogens. | NCBI Gene, ClinVar |
| Squamous cell carcinoma | Dysregulation of SPRR4 expression has been observed in keratinocyte-derived tumors, potentially affecting cell adhesion and invasion. | COSMIC, NCBI Gene |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Skin | 78.5 | High |
| Esophagus | 45.2 | Medium |
| Oral mucosa | 62.1 | High |
| Vagina | 30.8 | Medium |
| Cervix | 12.3 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HaCaT (keratinocyte) | 85.0 | High expression; used as model for epidermal differentiation |
| NHEK (normal human epidermal keratinocytes) | 92.3 | High expression; primary keratinocyte line |
| A431 (epidermoid carcinoma) | 55.6 | Moderate expression; squamous cell carcinoma line |
| HeLa (cervical cancer) | 8.2 | Low expression; non-keratinocyte origin |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.152C>T (p.Pro51Leu) | Missense | <0.01% | Unknown; rare variant in population databases |
| c.205G>A (p.Gly69Arg) | Missense | <0.01% | Unknown; predicted benign by in silico tools |
| c.301_303del (p.Phe101del) | In-frame deletion | <0.01% | Unknown; may affect protein structure |
Mutation functional classification
Loss of Function (LOF)
No confirmed loss-of-function mutations reported in SPRR4; likely compensated by other SPRR family members.
Gain of Function (GOF)
No gain-of-function mutations documented.
Dominant Negative (DN)
No dominant-negative mutations described.
View complete mutation data：
Gene Ontology (GO)
| • structural molecule activity (GO:0005198) | • keratinocyte differentiation (GO:0030216) |
| • keratinization (GO:0031424) | • keratin filament (GO:0045095) |
| • cornified envelope (GO:0001533) |
Pathways
• Keratinocyte differentiation (Reactome: R-HSA-6809371)
• Formation of the cornified envelope (Reactome: R-HSA-6809370)
Protein Summary
SPRR4 encodes a 163-amino acid protein (UniProt Q9BTE6) belonging to the small proline-rich protein family. The protein is characterized by a central domain rich in proline and glutamine residues, flanked by N- and C-terminal regions containing cysteine and glutamine residues that serve as substrates for transglutaminase-mediated cross-linking. SPRR4 is incorporated into the cornified envelope during terminal differentiation of keratinocytes, providing mechanical resilience and barrier function. It is expressed in stratified squamous epithelia, particularly in skin, esophagus, and oral mucosa.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| SPRR4 Knockout HEK293 Cell Line | EDJ-KQ16781 | Human | 163778 | Details Get a Quote |
| SPRR4 Knockout HeLa Cell Line | EDJ-KQ58864 | Human | 163778 | Details Get a Quote |
| SPRR4 Knockout A-549 Cell Line | EDJ-KQ67355 | Human | 163778 | Details Get a Quote |
| SPRR4 Knockout HCT 116 Cell Line | EDJ-KQ75747 | Human | 163778 | Details Get a Quote |
