FCN3 Gene (Ficolin-3)
Innate Immunity Pattern Recognition Molecule
Gene Information Card
| Symbol | FCN3 |
|---|---|
| Full Name | Ficolin-3 |
| Gene Type | Protein coding |
| Chromosomal Location | 1p36.11 |
| NCBI Gene ID | 8547 ncbi.nlm.nih.gov/gene/8547 |
| Ensembl ID | ENSG00000142748 |
| UniProt ID | O75636 |
| OMIM ID | 604973 |
| HGNC ID | 3625 |
| Aliases | FCN3, H-ficolin, Hakata antigen, ficolin-3 |
Description
FCN3 encodes ficolin-3 (H-ficolin), a serum protein that functions as a pattern recognition receptor in the innate immune system. It binds to carbohydrate moieties on microbial surfaces and activates the lectin complement pathway via association with mannose-binding lectin-associated serine proteases (MASPs). Ficolin-3 is primarily produced in the liver and lung, and its deficiency is associated with recurrent infections and autoimmune conditions.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| FCN3 deficiency | Loss-of-function mutations in FCN3 impair lectin pathway activation, reducing opsonization and clearance of pathogens. | ClinVar, OMIM |
| Recurrent respiratory infections | Deficient ficolin-3 leads to increased susceptibility to encapsulated bacteria (e.g., Streptococcus pneumoniae). | ClinVar, OMIM |
| Autoimmune diseases (e.g., systemic lupus erythematosus) | Altered ficolin-3 levels may contribute to immune complex clearance defects. | NCBI Gene, OMIM |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Liver | 48.2 | High |
| Lung | 12.5 | Medium |
| Spleen | 6.8 | Low |
| Kidney | 2.1 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HepG2 | 35.0 | Hepatocyte cell line |
| A549 | 8.5 | Lung epithelial cell line |
| THP-1 | 1.2 | Monocyte cell line |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.497C>T (p.Thr166Met) | Missense | Rare (MAF <0.01) | Reduced ficolin-3 secretion and function |
| c.163delC (p.Leu55Cysfs*26) | Frameshift | Very rare | Complete loss of protein expression |
| c.743G>A (p.Arg248Gln) | Missense | Rare | Impaired ligand binding |
Mutation functional classification
Loss of Function (LOF)
Frameshift and nonsense mutations (e.g., c.163delC) cause complete loss of ficolin-3 protein, leading to lectin pathway deficiency.
Gain of Function (GOF)
No gain-of-function mutations reported in FCN3.
Dominant Negative (DN)
No dominant-negative mutations described; deficiency is typically recessive.
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)
Protein Summary
Ficolin-3 (H-ficolin) is a 299-amino acid serum protein composed of a collagen-like domain and a fibrinogen-like domain. It forms homotrimers that further oligomerize into higher-order structures. The fibrinogen-like domain binds to acetylated sugars (e.g., GlcNAc) on microbial surfaces, while the collagen-like domain interacts with MASP-1/2 to trigger complement activation. Ficolin-3 is the most abundant ficolin in human serum and is critical for first-line defense against encapsulated bacteria.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| FCN3 Knockout HEK293 Cell Line | EDJ-KQ6279 | Human | 8547 | Details Get a Quote |
| FCN3 Knockout HeLa Cell Line | EDJ-KQ54938 | Human | 8547 | Details Get a Quote |
| FCN3 Knockout A-549 Cell Line | EDJ-KQ63422 | Human | 8547 | Details Get a Quote |
| FCN3 Knockout HCT 116 Cell Line | EDJ-KQ71888 | Human | 8547 | Details Get a Quote |
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