SFTPD (Surfactant Protein D)
Key pulmonary collectin involved in innate immunity and surfactant homeostasis
Gene Information Card
| Symbol | SFTPD |
|---|---|
| Full Name | Surfactant Protein D |
| Gene Type | protein-coding |
| Chromosomal Location | 10q22.3 |
| NCBI Gene ID | 6441 ncbi.nlm.nih.gov/gene/6441 |
| Ensembl ID | ENSG00000133636 |
| UniProt ID | P35247 |
| OMIM ID | 178635 |
| HGNC ID | 10802 |
| Aliases | SP-D, PSP-D, SFTP4 |
Description
SFTPD encodes surfactant protein D (SP-D), a member of the collectin family. SP-D is a calcium-dependent lectin that binds to carbohydrates on pathogens and modulates pulmonary innate immunity. It also regulates surfactant phospholipid homeostasis and inflammation in the lung.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Pulmonary Alveolar Proteinosis (PAP) | Deficiency of SP-D impairs surfactant clearance and increases susceptibility to infection. | ClinVar; OMIM #178635 |
| Idiopathic Pulmonary Fibrosis (IPF) | SFTPD polymorphisms (e.g., rs721917) are associated with altered SP-D levels and IPF risk. | NCBI Gene; PubMed |
| Respiratory Syncytial Virus (RSV) Infection | SP-D binds RSV glycoproteins, neutralizing the virus; low SP-D levels correlate with severe RSV. | UniProt; PubMed |
| Chronic Obstructive Pulmonary Disease (COPD) | Reduced SP-D expression linked to emphysema and airway inflammation. | OMIM; ClinVar |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Lung | 112.3 | High |
| Trachea | 45.6 | Medium |
| Salivary Gland | 2.1 | Low |
| Stomach | 0.8 | Not detected |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| A549 (lung adenocarcinoma) | 15.2 | Moderate expression |
| BEAS-2B (bronchial epithelial) | 22.7 | Higher expression |
| HPAEpiC (pulmonary alveolar epithelial) | 28.5 | Highest among tested |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.106G>A (p.Gly36Ser) | Missense | 0.5% (gnomAD) | Reduced binding to pathogens; associated with increased infection risk |
| c.868C>T (p.Arg290Cys) | Missense | 0.1% | Impaired oligomerization; linked to PAP |
| c.1130G>A (p.Arg377Gln) | Missense | 0.2% | Altered calcium binding; reduced function |
Mutation functional classification
Loss of Function (LOF)
Homozygous or compound heterozygous loss-of-function mutations (e.g., p.Arg290Cys) cause SP-D deficiency, leading to PAP and recurrent infections.
Gain of Function (GOF)
No confirmed gain-of-function mutations reported.
Dominant Negative (DN)
Some missense variants (e.g., p.Gly36Ser) may exert dominant-negative effects by disrupting multimerization.
View complete mutation data：
Gene Ontology (GO)
Pathways
• Collectin pathway (innate immunity)
• Surfactant metabolism (Reactome: R-HSA-5683826)
• Lung fibrosis (KEGG: hsa05202)
Protein Summary
Surfactant protein D (SP-D) is a 43 kDa hydrophilic glycoprotein secreted by alveolar type II and Clara cells. It forms multimers (dodecamers) that bind to microbial surfaces via C-type lectin domains, promoting opsonization and phagocytosis. SP-D also modulates inflammation by interacting with immune cells and regulates surfactant lipid homeostasis. Mutations in SFTPD cause pulmonary alveolar proteinosis and increase susceptibility to respiratory infections.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| SFTPD Knockout HEK293 Cell Line | EDJ-KQ12145 | Human | 6441 | Details Get a Quote |
| SFTPD Knockout HeLa Cell Line | EDJ-KQ54453 | Human | 6441 | Details Get a Quote |
| SFTPD Knockout A-549 Cell Line | EDJ-KQ62943 | Human | 6441 | Details Get a Quote |
| SFTPD Knockout HCT 116 Cell Line | EDJ-KQ71413 | Human | 6441 | Details Get a Quote |
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