FCN1 (Ficolin 1) Gene
Key Pattern Recognition Molecule in Innate Immunity
Gene Information Card
| Symbol | FCN1 |
|---|---|
| Full Name | Ficolin 1 |
| Gene Type | Protein coding |
| Chromosomal Location | 9q34.3 |
| NCBI Gene ID | 2219 ncbi.nlm.nih.gov/gene/2219 |
| Ensembl ID | ENSG00000185262 |
| UniProt ID | O00602 |
| OMIM ID | 601252 |
| HGNC ID | 3623 |
| Aliases | FCN, M-ficolin, ficolin-A |
Description
FCN1 encodes ficolin 1 (M-ficolin), a soluble pattern recognition molecule of the innate immune system. It is primarily expressed in monocytes and neutrophils and functions as a lectin that binds to carbohydrate moieties on microbial surfaces, activating the lectin complement pathway via associated serine proteases (MASPs). Ficolin 1 also acts as an opsonin, enhancing phagocytosis.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Recurrent respiratory infections | Deficiency of ficolin 1 may impair complement activation and opsonization, increasing susceptibility to infections | ClinVar; PMID: 22112314 |
| Systemic lupus erythematosus (SLE) | Altered ficolin 1 levels and polymorphisms associated with disease susceptibility and activity | OMIM; PMID: 23325525 |
| Inflammatory bowel disease | FCN1 expression changes linked to mucosal inflammation and dysbiosis | NCBI Gene; PMID: 28798025 |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Bone marrow | 12.5 | Medium |
| Spleen | 8.3 | Medium |
| Lung | 5.1 | Low |
| Liver | 2.0 | Low |
| Whole blood | 15.2 | High |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| THP-1 (monocytic) | 18.4 | High expression; model for monocyte/macrophage studies |
| HL-60 (promyelocytic) | 9.7 | Moderate expression; neutrophil-like differentiation |
| K-562 (erythroleukemia) | 0.5 | Very low expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.635G>A (p.Arg212Gln) | Missense | 0.01% (gnomAD) | Reduced ligand binding and complement activation |
| c.772C>T (p.Arg258Trp) | Missense | 0.005% (gnomAD) | Impaired secretion and function |
| c.1048C>T (p.Arg350*) | Nonsense | 0.001% (gnomAD) | Premature truncation; loss of function |
Mutation functional classification
Loss of Function (LOF)
Nonsense and missense mutations that reduce protein secretion, ligand binding, or complement activation (e.g., p.Arg350*, p.Arg212Gln).
Gain of Function (GOF)
No gain-of-function mutations reported in FCN1.
Dominant Negative (DN)
No dominant-negative mutations described for FCN1.
View complete mutation data：
Gene Ontology (GO)
| • complement activation (GO:0001867) | • protein binding (GO:0005515) |
| • carbohydrate binding (GO:0030246) | • extracellular region (GO:0005576) |
| • plasma membrane (GO:0005886) |
Pathways
• Lectin complement pathway (Reactome: R-HSA-166662)
• Innate immune system (Reactome: R-HSA-168249)
• Ficolin-rich granule lumen (GO:0101002)
Protein Summary
Ficolin 1 (M-ficolin) is a 35 kDa secreted protein composed of an N-terminal collagen-like domain and a C-terminal fibrinogen-like domain. It forms oligomers and recognizes acetylated sugars (e.g., GlcNAc) on microbial surfaces. Upon binding, it recruits MASP-1/2 to activate the lectin complement pathway, leading to opsonization and inflammation. Ficolin 1 is stored in specific granules of neutrophils and monocytes.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| FCN1 Knockout HEK293 Cell Line | EDJ-KQ4583 | Human | 2219 | Details Get a Quote |
| FCN1 Knockout HeLa Cell Line | EDJ-KQ53213 | Human | 2219 | Details Get a Quote |
| FCN1 Knockout A-549 Cell Line | EDJ-KQ61694 | Human | 2219 | Details Get a Quote |
| FCN1 Knockout HCT 116 Cell Line | EDJ-KQ70181 | Human | 2219 | Details Get a Quote |
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