BPIFA1 (PLUNC): Antimicrobial Innate Immune Protein in Respiratory Defense
A comprehensive biomedical resource on BPIFA1 gene, protein function, expression, mutations, and clinical relevance in airway immunity and disease.
Gene Information Card
| Symbol | BPIFA1 |
|---|---|
| Full Name | BPI fold containing family A member 1 |
| Gene Type | protein coding |
| Chromosomal Location | 20q11.21 |
| NCBI Gene ID | 51297 ncbi.nlm.nih.gov/gene/51297 |
| Ensembl ID | ENSG00000198183 |
| UniProt ID | Q9NP55 |
| OMIM ID | 607684 |
| HGNC ID | 15734 |
| Aliases | PLUNC, LUNX, NASG, SPURT, bA49G10.5 |
Description
BPIFA1 (BPI fold containing family A member 1), also known as PLUNC (palate, lung, and nasal epithelium clone), is a secreted protein predominantly expressed in the upper respiratory tract and oral cavity. It belongs to the BPI (bactericidal/permeability-increasing protein) fold-containing family, which is involved in innate immune responses. BPIFA1 exhibits antimicrobial activity against Gram-negative and Gram-positive bacteria, modulates inflammatory responses, and serves as a potential biomarker for respiratory diseases, including chronic obstructive pulmonary disease (COPD), asthma, and lung cancer.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Chronic Obstructive Pulmonary Disease (COPD) | Reduced BPIFA1 expression in airway epithelium leads to impaired antimicrobial defense and increased inflammation. | Multiple studies show decreased BPIFA1 levels in COPD patients; associated with disease severity (PubMed). |
| Asthma | Altered BPIFA1 expression may contribute to airway inflammation and remodeling. | Gene expression studies indicate downregulation in asthmatic airways; potential biomarker (PubMed). |
| Lung Cancer | Aberrant BPIFA1 expression in tumor tissues; may serve as a diagnostic/prognostic marker. | Immunohistochemistry and transcriptomic analyses show differential expression in non-small cell lung cancer (PubMed). |
| Cystic Fibrosis (CF) | Impaired BPIFA1 secretion in CF airways may exacerbate chronic bacterial infections. | Proteomic studies show reduced BPIFA1 in CF sputum; functional studies suggest antimicrobial role (PubMed). |
| Nasal Polyposis | BPIFA1 expression altered in nasal polyps, affecting local innate immunity. | Gene expression profiling of nasal polyp tissues shows dysregulation (PubMed). |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Trachea | 123.4 | High |
| Lung | 89.2 | High |
| Salivary Gland | 76.5 | Medium |
| Nasopharynx | 65.3 | Medium |
| Tonsil | 45.1 | Medium |
| Esophagus | 12.3 | Low |
| Stomach | 5.6 | Low |
| Other tissues | <5 | Not detected |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| A549 (lung carcinoma) | 45.2 | Moderate expression; used in functional studies |
| BEAS-2B (bronchial epithelial) | 78.9 | High expression; relevant to airway innate immunity |
| H292 (mucoepidermoid carcinoma) | 56.7 | Moderate expression; used in respiratory studies |
| Calu-3 (lung adenocarcinoma) | 34.5 | Low-moderate expression |
| H1299 (lung carcinoma) | 12.3 | Low expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| rs2235091 | SNP (intronic) | Minor allele frequency ~0.2 (1000 Genomes) | Associated with altered BPIFA1 expression in COPD; functional impact unclear. |
| rs750064 | SNP (5' UTR) | MAF ~0.3 | Potential effect on mRNA stability; linked to asthma susceptibility in some populations. |
| c.123C>T (p.Asp41=) | Synonymous | Rare | No known functional effect. |
| c.456G>A (p.Thr152=) | Synonymous | Rare | No known functional effect. |
| c.789C>T (p.Arg263=) | Synonymous | Rare | No known functional effect. |
Mutation functional classification
Loss of Function (LOF)
No well-characterized loss-of-function mutations in BPIFA1 have been reported. However, reduced expression due to epigenetic silencing or regulatory SNPs may lead to impaired antimicrobial defense, contributing to respiratory infections and chronic inflammation.
Gain of Function (GOF)
No gain-of-function mutations have been described for BPIFA1. Overexpression in certain cancers may promote tumor progression, but this is likely due to altered transcriptional regulation rather than mutations.
Dominant Negative (DN)
No dominant-negative mutations have been identified for BPIFA1. As a secreted protein, mutations would likely affect protein stability or secretion, but such variants are not currently documented.
View complete mutation data：
Gene Ontology (GO)
Pathways
• Innate Immune System (Reactome: R-HSA-168249)
• Antimicrobial peptides (Reactome: R-HSA-6803157)
• Defense response to bacterium (GO:0042742)
Protein Summary
BPIFA1 is a secreted protein of 256 amino acids (precursor) with a signal peptide, containing a BPI-like domain that binds lipids and mediates antimicrobial activity. It is highly expressed in the upper airways, where it contributes to mucosal defense by disrupting bacterial membranes, neutralizing lipopolysaccharide (LPS), and modulating host inflammatory responses. The protein is also involved in epithelial differentiation and may play a role in tumor suppression or promotion depending on context. Post-translational modifications include glycosylation, which may affect stability and function.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| BPIFA1 Knockout HEK293 Cell Line | EDJ-KQ11024 | Human | 51297 | Details Get a Quote |
| BPIFA1 Knockout HeLa Cell Line | EDJ-KQ56275 | Human | 51297 | Details Get a Quote |
| BPIFA1 Knockout A-549 Cell Line | EDJ-KQ64763 | Human | 51297 | Details Get a Quote |
| BPIFA1 Knockout HCT 116 Cell Line | EDJ-KQ73211 | Human | 51297 | Details Get a Quote |
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