FCN1 explained

Ficolin-1, and also commonly termed M-ficolin is a protein that in humans is encoded by the FCN1 gene.^{[1] [2] [3]}

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. M-ficolin levels reflect disease activity and predict remission in early rheumatoid arthritis.

Further reading

• Lu J, Le Y . Ficolins and the fibrinogen-like domain . Immunobiology . 199 . 2 . 190–9 . 1999 . 9777405 . 10.1016/s0171-2985(98)80026-0.
• Ichijo H, Hellman U, Wernstedt C . Molecular cloning and characterization of ficolin, a multimeric protein with fibrinogen- and collagen-like domains . J. Biol. Chem. . 268 . 19 . 14505–13 . 1993 . 10.1016/S0021-9258(19)85267-5 . 7686157 . etal. free .
• Matsushita M, Endo Y, Taira S . A novel human serum lectin with collagen- and fibrinogen-like domains that functions as an opsonin . J. Biol. Chem. . 271 . 5 . 2448–54 . 1996 . 8576206 . 10.1074/jbc.271.5.2448 . etal. free .
• Harumiya S, Takeda K, Sugiura T . Characterization of ficolins as novel elastin-binding proteins and molecular cloning of human ficolin-1 . J. Biochem. . 120 . 4 . 745–51 . 1997 . 8947836 . 10.1093/oxfordjournals.jbchem.a021474. etal.
• Le Y, Tan SM, Lee SH . Purification and binding properties of a human ficolin-like protein . J. Immunol. Methods . 204 . 1 . 43–9 . 1997 . 9202708 . 10.1016/S0022-1759(97)00029-X . etal.
• Matsushita M, Endo Y, Fujita T . Cutting edge: complement-activating complex of ficolin and mannose-binding lectin-associated serine protease . J. Immunol. . 164 . 5 . 2281–4 . 2000 . 10679061 . 10.4049/jimmunol.164.5.2281. free .
• Strausberg RL, Feingold EA, Grouse LH . Generation and initial analysis of more than 15,000 full-length human and mouse cDNA sequences . Proc. Natl. Acad. Sci. U.S.A. . 99 . 26 . 16899–903 . 2003 . 12477932 . 10.1073/pnas.242603899 . 139241 . 2002PNAS...9916899M . etal. free .
• Zeng L, Dai J, Ying K . Identification of a novel human angiopoietin-like gene expressed mainly in heart . J. Hum. Genet. . 48 . 3 . 159–62 . 2003 . 12624729 . 10.1007/s100380300025 . etal. free .
• Gregory LA, Thielens NM, Matsushita M . The X-ray structure of human mannan-binding lectin-associated protein 19 (MAp19) and its interaction site with mannan-binding lectin and L-ficolin . J. Biol. Chem. . 279 . 28 . 29391–7 . 2004 . 15117939 . 10.1074/jbc.M402687200 . etal. free .
• Zhang Z, Henzel WJ . Signal peptide prediction based on analysis of experimentally verified cleavage sites . Protein Sci. . 13 . 10 . 2819–24 . 2005 . 15340161 . 10.1110/ps.04682504 . 2286551 .
• Gerhard DS, Wagner L, Feingold EA . The status, quality, and expansion of the NIH full-length cDNA project: the Mammalian Gene Collection (MGC) . Genome Res. . 14 . 10B . 2121–7 . 2004 . 15489334 . 10.1101/gr.2596504 . 528928 . etal.
• Frederiksen PD, Thiel S, Larsen CB, Jensenius JC . M-ficolin, an innate immune defence molecule, binds patterns of acetyl groups and activates complement . Scand. J. Immunol. . 62 . 5 . 462–73 . 2006 . 16305643 . 10.1111/j.1365-3083.2005.01685.x . 35639359 . free .
• Tanio M, Kondo S, Sugio S, Kohno T . Trivalent recognition unit of innate immunity system: crystal structure of trimeric human M-ficolin fibrinogen-like domain . J. Biol. Chem. . 282 . 6 . 3889–95 . 2007 . 17148457 . 10.1074/jbc.M608627200 . free .

Arthritis Rheum. 2013 Dec;65(12):3045-50. doi: 10.1002/art.38179.M-ficolin levels reflect disease activity and predict remission in early rheumatoid arthritis.Ammitzbøll CG1, Thiel S, Jensenius JC, Ellingsen T, Hørslev-Petersen K, Hetland ML, Junker P, Krogh NS, Østergaard M, Stengaard-Pedersen K.

Notes and References

1. Lu J, Tay PN, Kon OL, Reid KB . Human ficolin: cDNA cloning, demonstration of peripheral blood leucocytes as the major site of synthesis and assignment of the gene to chromosome 9 . Biochem J . 313 . 2. 473–8 . Mar 1996 . 8573080 . 1216931 . 10.1042/bj3130473.
2. Endo Y, Sato Y, Matsushita M, Fujita T . Cloning and characterization of the human lectin P35 gene and its related gene . Genomics . 36 . 3 . 515–21 . Feb 1997 . 8884275 . 10.1006/geno.1996.0497 .
3. Web site: Entrez Gene: FCN1 ficolin (collagen/fibrinogen domain containing) 1.