SLPI (Secretory Leukocyte Peptidase Inhibitor)
A multifunctional serine protease inhibitor involved in inflammation, tissue repair, and host defense.
Gene Information Card
| Symbol | SLPI |
|---|---|
| Full Name | Secretory Leukocyte Peptidase Inhibitor |
| Gene Type | Protein coding |
| Chromosomal Location | 20q13.12 |
| NCBI Gene ID | 6590 ncbi.nlm.nih.gov/gene/6590 |
| Ensembl ID | ENSG00000124107 |
| UniProt ID | P03973 |
| OMIM ID | 107285 |
| HGNC ID | 11092 |
| Aliases | ALP, ALK1, BLPI, HUSI, MPI, WAP4, WFDC4 |
Description
SLPI encodes a secreted serine protease inhibitor that protects epithelial tissues from proteolytic damage during inflammation. It inhibits neutrophil elastase, cathepsin G, and trypsin, and also exhibits antimicrobial, anti-inflammatory, and wound-healing properties. The gene is expressed in mucosal surfaces, including the respiratory tract, salivary glands, and reproductive organs.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Chronic Obstructive Pulmonary Disease (COPD) | Reduced SLPI levels lead to unchecked neutrophil elastase activity, contributing to alveolar destruction and airway inflammation. | ClinVar, NCBI Gene Reviews |
| Cystic Fibrosis | Impaired SLPI function exacerbates protease-antiprotease imbalance in airway secretions, promoting tissue damage. | NCBI Gene, PubMed |
| Inflammatory Bowel Disease | Decreased SLPI expression in intestinal mucosa correlates with increased proteolytic activity and inflammation. | UniProt, OMIM |
| Oral Squamous Cell Carcinoma | SLPI overexpression may promote tumor invasion by modulating extracellular matrix remodeling. | COSMIC, PubMed |
| Endometriosis | Altered SLPI levels in endometrial tissue affect local protease activity and inflammatory response. | NCBI Gene, PubMed |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Salivary gland | 112.5 | High |
| Lung | 78.3 | High |
| Trachea | 65.2 | High |
| Prostate | 42.1 | Medium |
| Cervix, uterine | 38.9 | Medium |
| Kidney | 12.4 | Low |
| Liver | 3.1 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| A549 (lung carcinoma) | 85.6 | High expression |
| HeLa (cervical adenocarcinoma) | 62.3 | Moderate expression |
| HepG2 (hepatocellular carcinoma) | 5.2 | Low expression |
| MCF7 (breast adenocarcinoma) | 18.7 | Low to moderate expression |
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 affects translation initiation; loss of function |
| c.214C>T (p.Arg72Cys) | Missense | 0.02% | May disrupt disulfide bond formation; reduced inhibitor activity |
| c.373G>A (p.Gly125Ser) | Missense | 0.01% | Unknown significance; possibly benign |
Mutation functional classification
Loss of Function (LOF)
Mutations affecting the signal peptide or conserved cysteine residues (e.g., p.Arg72Cys) are predicted to impair secretion or folding, reducing protease inhibitory capacity.
Gain of Function (GOF)
No well-characterized gain-of-function mutations reported in SLPI.
Dominant Negative (DN)
No evidence of dominant-negative effects for SLPI mutations.
View complete mutation data：
Gene Ontology (GO)
Pathways
• Neutrophil degranulation (Reactome: R-HSA-6798695)
• Innate immune system (Reactome: R-HSA-168249)
• Peptide hormone metabolism (Reactome: R-HSA-2980736)
Protein Summary
SLPI is a 132-amino-acid secreted protein containing two WAP (whey acidic protein) domains. It functions as a potent inhibitor of serine proteases, particularly neutrophil elastase, and also possesses antibacterial and anti-inflammatory activities. The protein is found in mucus, saliva, tears, and seminal plasma, playing a critical role in protecting mucosal surfaces from proteolytic damage and infection.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| SLPI Knockout HEK293 Cell Line | EDJ-KQ3027 | Human | 6590 | Details Get a Quote |
| SLPI Knockout A-549 Cell Line | EDJ-KQ22880 | Human | 6590 | Details Get a Quote |
| SLPI Knockout HeLa Cell Line | EDJ-KQ24247 | Human | 6590 | Details Get a Quote |
| SLPI Knockout HCT 116 Cell Line | EDJ-KQ71481 | Human | 6590 | Details Get a Quote |
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