FCN can refer to one of the following:
Ficolin-2, which was initially identified as L-ficolin, is a protein that in humans is encoded by the FCN2 gene.
The product of this gene belongs to the ficolin family of proteins. This family is characterized by the presence of a leader peptide, a short N-terminal segment, followed by a collagen-like region, and a C-terminal fibrinogen-like domain. This gene is predominantly expressed in the liver, and has been shown to have carbohydrate binding and opsonic activities. Alternatively spliced transcript variants encoding different isoforms have been identified.
Ficolin-1, and also commonly termed M-ficolin is a protein that in humans is encoded by the FCN1 gene.
Proteins of the ficolin family consist of a leader peptide, a short N-terminal segment, followed by a collagen-like domain, and a C-terminal fibrinogen-like domain. The name of ficolin was derived from the latter two domains. The collagen-like and the fibrinogen-like domains are also found in other proteins such as tenascins, while the former is also found in complement protein C1q and collectins, which include mannose-binding lectin and lung surfactant proteins. Ficolins selectively recognize acetylated compounds. M-ficolin encoded by FCN1 is predominantly expressed in the peripheral blood leukocytes, and has been postulated to function as a plasma protein with elastin-binding activity. Several SNPs have been described in the FCN1 gene with impact on serum concentrations of M-ficolin and the ligand binding ability