SFTPC Gene: Surfactant Protein C
Key regulator of pulmonary surfactant function and lung homeostasis
Gene Information Card
| Symbol | SFTPC |
|---|---|
| Full Name | Surfactant Protein C |
| Gene Type | protein-coding |
| Chromosomal Location | 8p21.3 |
| NCBI Gene ID | 6440 ncbi.nlm.nih.gov/gene/6440 |
| Ensembl ID | ENSG00000168484 |
| UniProt ID | P11686 |
| OMIM ID | 178620 |
| HGNC ID | 10802 |
| Aliases | SP-C, PSP-C, SFTP2, BRICD6 |
Description
The SFTPC gene encodes surfactant protein C (SP-C), a hydrophobic protein essential for pulmonary surfactant function. SP-C is synthesized as a 197-amino-acid proprotein (proSP-C) in alveolar type II cells, then proteolytically processed to the mature 35-amino-acid form. Mature SP-C reduces surface tension at the air-liquid interface in alveoli, preventing collapse during exhalation. Mutations in SFTPC cause familial interstitial lung disease (ILD) and sporadic forms of pulmonary fibrosis.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Surfactant metabolism dysfunction, pulmonary, 2 (SMDP2) | Dominant-negative or gain-of-toxic-function mutations in SFTPC lead to misfolded proSP-C, ER stress, and apoptosis of alveolar type II cells | OMIM #610913; ClinVar |
| Idiopathic pulmonary fibrosis (IPF) | SFTPC mutations (e.g., I73T) cause abnormal protein aggregation and chronic epithelial injury, promoting fibrosis | NCBI Gene; ClinVar |
| Interstitial lung disease (ILD) in children | De novo or inherited SFTPC variants disrupt surfactant homeostasis, leading to respiratory distress and ILD | OMIM; PubMed |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Lung | 124.2 | High |
| Trachea | 12.5 | Low |
| Thyroid | 0.3 | Not detected |
| Other tissues | 0.0 | Not detected |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| A549 (lung adenocarcinoma) | 0.0 | No endogenous expression; used for transfection studies |
| NCI-H441 (lung papillary adenocarcinoma) | 45.8 | Moderate expression; Clara-like cell line |
| Primary alveolar type II cells | 150.0 | High expression; physiological source |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.218T>C (p.I73T) | Missense | ~30% of familial SFTPC cases | Dominant-negative; causes ER retention and aggregation of proSP-C |
| c.460+1G>A | Splice site | Rare | Loss of function; leads to truncated protein |
| c.173C>T (p.A58D) | Missense | Rare | Gain of toxic function; misfolding and ER stress |
| c.424C>T (p.R142W) | Missense | Rare | Dominant-negative; impaired trafficking |
Mutation functional classification
Loss of Function (LOF)
Rare; splice-site or nonsense variants that reduce SP-C production, but haploinsufficiency is not a major disease mechanism.
Gain of Function (GOF)
Not typical; most pathogenic mutations are dominant-negative or gain-of-toxic-function via misfolding.
Dominant Negative (DN)
Common; e.g., I73T and A58D cause mutant proSP-C to aggregate and disrupt wild-type protein processing, leading to ER stress and cell death.
View complete mutation data：
Gene Ontology (GO)
| • GO:0005576 - extracellular region | • GO:0005615 - extracellular space |
| • GO:0006629 - lipid metabolic process | • GO:0008289 - lipid binding |
| • GO:0016021 - integral component of membrane | • GO:0030324 - lung development |
| • GO:0043129 - surfactant homeostasis | • GO:0070062 - extracellular exosome |
Pathways
• Pulmonary surfactant metabolism (Reactome: R-HSA-5683826)
• Unfolded protein response (UPR) in ER stress (Reactome: R-HSA-381119)
Protein Summary
Surfactant protein C (SP-C) is a 4.2 kDa hydrophobic peptide produced exclusively in alveolar type II cells. The precursor proSP-C (21 kDa) undergoes C-terminal and N-terminal proteolytic cleavage to yield the mature 35-residue form. Mature SP-C contains a transmembrane domain and two palmitoylated cysteine residues, enabling strong interaction with phospholipids. SP-C is critical for reducing surface tension and stabilizing the surfactant film. Mutations in SFTPC cause protein misfolding, ER stress, and apoptosis, leading to interstitial lung disease and pulmonary fibrosis.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| SFTPC Knockout HEK293 Cell Line | EDJ-KQ3915 | Human | 6440 | Details Get a Quote |
| SFTPC Knockout HeLa Cell Line | EDJ-KQ54452 | Human | 6440 | Details Get a Quote |
| SFTPC Knockout A-549 Cell Line | EDJ-KQ62942 | Human | 6440 | Details Get a Quote |
| SFTPC Knockout HCT 116 Cell Line | EDJ-KQ71412 | Human | 6440 | Details Get a Quote |
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