SPRR1A (Small Proline-Rich Protein 1A)
A cornified envelope precursor involved in epidermal barrier function and squamous cell carcinoma
Gene Information Card
| Symbol | SPRR1A |
|---|---|
| Full Name | Small Proline-Rich Protein 1A |
| Gene Type | Protein coding |
| Chromosomal Location | 1q21.3 |
| NCBI Gene ID | 6698 ncbi.nlm.nih.gov/gene/6698 |
| Ensembl ID | ENSG00000169442 |
| UniProt ID | P35325 |
| OMIM ID | 182265 |
| HGNC ID | 11256 |
| Aliases | SPR1, SPRK, GADD33 |
Description
SPRR1A encodes a member of the small proline-rich protein family, which are components of the cornified cell envelope in stratified squamous epithelia. The protein is cross-linked by transglutaminases during terminal differentiation of keratinocytes, contributing to the barrier function of the epidermis. SPRR1A expression is induced by UV radiation, oxidative stress, and during wound healing. It is also upregulated in various squamous cell carcinomas and may play a role in tumor progression.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Squamous cell carcinoma (skin) | Overexpression of SPRR1A in keratinocytes promotes cell survival and proliferation, potentially contributing to tumorigenesis. | PubMed: 10488074 |
| Psoriasis | Increased SPRR1A expression in psoriatic epidermis correlates with abnormal keratinocyte differentiation and barrier dysfunction. | PubMed: 10651973 |
| Wound healing | SPRR1A is induced during re-epithelialization and may facilitate keratinocyte migration and matrix remodeling. | PubMed: 10861426 |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Skin | 12.5 | High |
| Esophagus | 8.3 | Medium |
| Oral mucosa | 7.1 | Medium |
| Lung | 1.2 | Low |
| Breast | 0.5 | Not detected |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HaCaT (keratinocyte) | 15.0 | High expression; used as model for epidermal differentiation |
| A431 (epidermoid carcinoma) | 10.2 | Elevated compared to normal keratinocytes |
| NHEK (normal human epidermal keratinocytes) | 9.8 | Basal expression increases upon differentiation |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.1A>G (p.Met1?) | Missense | <0.01% | Likely loss of start codon; functional impact unknown |
| c.85C>T (p.Arg29Trp) | Missense | <0.01% | Rare variant; no disease association reported |
Mutation functional classification
Loss of Function (LOF)
No confirmed loss-of-function mutations reported in SPRR1A.
Gain of Function (GOF)
Overexpression in squamous cell carcinoma suggests potential gain-of-function role in tumorigenesis.
Dominant Negative (DN)
No dominant-negative mutations described.
View complete mutation data：
Gene Ontology (GO)
| • cornified envelope | • keratinocyte differentiation |
| • epidermis development | • structural constituent of skin epidermis |
| • response to UV-B | • response to oxidative stress |
Pathways
• Keratinocyte differentiation (Reactome: R-HSA-6809371)
• Formation of the cornified envelope (Reactome: R-HSA-6809374)
Protein Summary
SPRR1A is a 22.5 kDa protein (89 amino acids) characterized by a central domain of proline-rich repeats flanked by glutamine- and lysine-rich regions. It serves as a substrate for transglutaminase 1, which cross-links SPRR1A 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 tightly regulated during epidermal development and is induced by stress signals.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| SPRR1A Knockout HEK293 Cell Line | EDJ-KQ50649 | Human | 6698 | Details Get a Quote |
| SPRR1A Knockout HeLa Cell Line | EDJ-KQ54550 | Human | 6698 | Details Get a Quote |
| SPRR1A Knockout A-549 Cell Line | EDJ-KQ63034 | Human | 6698 | Details Get a Quote |
| SPRR1A Knockout HCT 116 Cell Line | EDJ-KQ71510 | Human | 6698 | Details Get a Quote |
