SPRR3 Gene - Small Proline Rich Protein 3
A key component of the cornified cell envelope in stratified squamous epithelia
Gene Information Card
| Symbol | SPRR3 |
|---|---|
| Full Name | Small Proline Rich Protein 3 |
| Gene Type | Protein coding |
| Chromosomal Location | 1q21.3 |
| NCBI Gene ID | 6707 ncbi.nlm.nih.gov/gene/6707 |
| Ensembl ID | ENSG00000163349 |
| UniProt ID | Q9UBC9 |
| OMIM ID | 182268 |
| HGNC ID | 11269 |
| Aliases | SPR3, SPRR1B, SPRR2C |
Description
SPRR3 encodes a member of the small proline-rich protein family, which are cross-linked by transglutaminases to form the cornified cell envelope in stratified squamous epithelia. This protein is specifically expressed in the upper layers of the epidermis and in oral, esophageal, and vaginal epithelia. It plays a role in barrier function and is upregulated during keratinocyte differentiation. SPRR3 expression is altered in various cancers, particularly esophageal squamous cell carcinoma.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Esophageal Squamous Cell Carcinoma | Downregulation of SPRR3 may impair epithelial barrier integrity, contributing to tumor progression. | PMID: 19030189 |
| Psoriasis | Overexpression of SPRR3 in psoriatic epidermis suggests involvement in abnormal keratinocyte differentiation. | PMID: 12651938 |
| Atopic Dermatitis | Reduced SPRR3 expression may compromise skin barrier function, increasing allergen penetration. | PMID: 22158542 |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Esophagus | 112.3 | High |
| Skin | 45.6 | Medium |
| Oral Mucosa | 38.2 | Medium |
| Vagina | 29.8 | Medium |
| Lung | 2.1 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HaCaT (keratinocyte) | 78.5 | Differentiated keratinocytes |
| KYSE-30 (esophageal cancer) | 12.3 | Downregulated vs normal |
| A431 (epidermoid carcinoma) | 55.2 | Moderate expression |
| HeLa (cervical) | 3.4 | Low expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.1A>G | Missense | <0.01% | Unknown |
| c.124C>T | Nonsense | <0.01% | Premature truncation |
| c.205G>A | Missense | <0.01% | Unknown |
Mutation functional classification
Loss of Function (LOF)
Nonsense mutations (e.g., c.124C>T) likely lead to loss of protein function, impairing cornified envelope formation.
Gain of Function (GOF)
No gain-of-function mutations reported.
Dominant Negative (DN)
No dominant-negative mutations reported.
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:0061436) |
Pathways
• Keratinocyte differentiation (Reactome: R-HSA-6809371)
• Formation of the cornified envelope (Reactome: R-HSA-6809374)
Protein Summary
SPRR3 is a 22.5 kDa protein (169 amino acids) containing tandem proline-rich repeats. It is a substrate for transglutaminase 1 and 3, which cross-link it to other envelope proteins (e.g., loricrin, involucrin) to form a rigid, insoluble barrier. The protein is localized to the cytoplasm and plasma membrane of differentiated keratinocytes. Its expression is regulated by AP1 and AP2 transcription factors.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| SPRR3 Knockout HEK293 Cell Line | EDJ-KQ50656 | Human | 6707 | Details Get a Quote |
| SPRR3 Knockout HeLa Cell Line | EDJ-KQ54558 | Human | 6707 | Details Get a Quote |
| SPRR3 Knockout A-549 Cell Line | EDJ-KQ63042 | Human | 6707 | Details Get a Quote |
| SPRR3 Knockout HCT 116 Cell Line | EDJ-KQ71518 | Human | 6707 | Details Get a Quote |
