SFTPB Gene - Surfactant Protein B
Essential for pulmonary surfactant function and lung homeostasis
Gene Information Card
| Symbol | SFTPB |
|---|---|
| Full Name | Surfactant Protein B |
| Gene Type | protein-coding |
| Chromosomal Location | 2p11.2 |
| NCBI Gene ID | 6439 ncbi.nlm.nih.gov/gene/6439 |
| Ensembl ID | ENSG00000168878 |
| UniProt ID | P07988 |
| OMIM ID | 178640 |
| HGNC ID | 10801 |
| Aliases | SP-B, SFTB3, PSP-B, SMDP1 |
Description
The SFTPB gene encodes surfactant protein B (SP-B), a hydrophobic protein essential for the formation and function of pulmonary surfactant. SP-B reduces surface tension at the air-liquid interface in the alveoli, preventing alveolar collapse during expiration. It is synthesized as a larger precursor (proSP-B) and proteolytically processed to the active mature form. Mutations in SFTPB cause hereditary surfactant protein B deficiency, leading to severe neonatal respiratory distress syndrome and pulmonary alveolar proteinosis.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Surfactant protein B deficiency | Loss-of-function mutations in SFTPB impair surfactant function, causing alveolar collapse and respiratory failure. | OMIM #265120; ClinVar |
| Neonatal respiratory distress syndrome | Deficiency of SP-B leads to inadequate surfactant, resulting in atelectasis and hypoxia in newborns. | NCBI Gene; OMIM |
| Pulmonary alveolar proteinosis | Accumulation of surfactant proteins and lipids in alveoli due to impaired surfactant clearance or function. | OMIM; ClinVar |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Lung | 124.3 | High |
| Trachea | 45.2 | Medium |
| Thyroid | 1.2 | Low |
| Testis | 0.8 | Low |
| Other tissues | <0.5 | Not detected |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| A549 (lung carcinoma) | 85.6 | High expression; type II pneumocyte model |
| NCI-H441 (lung adenocarcinoma) | 112.4 | High expression; Clara cell-like |
| BEAS-2B (bronchial epithelial) | 2.3 | Low expression |
| HEK293 (embryonic kidney) | 0.1 | Not expressed |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.397delC (p.Leu133CysfsTer24) | Frameshift | Common in SP-B deficiency | Loss of function; truncated protein |
| c.875G>A (p.Arg292Gln) | Missense | Rare | Impaired processing of proSP-B |
| c.997C>T (p.Arg333Ter) | Nonsense | Rare | Premature stop; loss of function |
| c.1A>G (p.Met1?) | Start loss | Rare | No translation initiation |
Mutation functional classification
Loss of Function (LOF)
Most SFTPB mutations are loss-of-function, leading to SP-B deficiency and severe respiratory disease.
Gain of Function (GOF)
No gain-of-function mutations reported for SFTPB.
Dominant Negative (DN)
No dominant-negative mutations reported; inheritance is autosomal recessive.
View complete mutation data：
Gene Ontology (GO)
Pathways
• Surfactant metabolism (Reactome: R-HSA-5683826)
• Lung surfactant metabolism (KEGG: hsa04974)
Protein Summary
Surfactant protein B (SP-B) is a 79-amino acid mature hydrophobic protein derived from a 381-residue precursor. It is secreted by type II pneumocytes and localizes to the alveolar lining fluid. SP-B is critical for the formation of the surfactant monolayer by promoting the adsorption and spreading of phospholipids. Deficiency leads to fatal neonatal respiratory distress. The protein contains three saposin-like domains and is highly conserved across mammals.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| SFTPB Knockout HEK293 Cell Line | EDJ-KQ2276 | Human | 6439 | Details Get a Quote |
| SFTPB Knockout HeLa Cell Line | EDJ-KQ54451 | Human | 6439 | Details Get a Quote |
| SFTPB Knockout A-549 Cell Line | EDJ-KQ62941 | Human | 6439 | Details Get a Quote |
| SFTPB Knockout HCT 116 Cell Line | EDJ-KQ71411 | Human | 6439 | Details Get a Quote |
Displaying Records 1 To 4 Of 4 Records
