The role of ficolins in innate immunity.
Ficolins are a group of proteins containing both a collagen-like domain and a fibrinogen-like domain and are found in varying tissues. Ficolins present in sera have a lectin activity toward N-acetylglucosamine through their fibrinogen-like domains. The domain organizations between ficolins and mannose-binding lectin (MBL) are very similar in that both consist of a collagen-like domain and a carbohydrate-binding domain, although their carbohydrate-binding moieties are different. MBL acts as an opsonin and activates complement in association with MBL-associated serine proteases (MASPs) and sMAP, truncated protein of MASP-2, via the lectin pathway. Like MBL, two types of human serum ficolins, L-ficolin/P35 and H-ficolin, are associated with MASPs and sMAP, and activate the lectin pathway. In addition, L-ficolin/P35 acts as an opsonin. These findings indicate that serum ficolins play an important a role in innate immunity in a similar manner to MBL.
Matsushita
Misao
M
Department of Biochemistry, Fukushima Medical University, Japan. mmatsu@fmu.ac.jp
Fujita
Teizo
T
D000818:Animals; D002352:Carrier Proteins / Q000737:chemistry / Q000276:immunology* / Q000378:metabolism*; D037582:Complement Pathway, Mannose-Binding Lectin / Q000276:immunology / Q000502:physiology; D006801:Humans; D007113:Immunity, Innate / Q000502:physiology*; D037102:Lectins; D037601:Mannose-Binding Lectin / Q000737:chemistry / Q000276:immunology / Q000378:metabolism; D050606:Mannose-Binding Protein-Associated Serine Proteases; D010802:Phylogeny; D012697:Serine Endopeptidases / Q000276:immunology / Q000378:metabolism; D000097604:Ficolins
D002352:Carrier Proteins; D037102:Lectins; D037601:Mannose-Binding Lectin; D050606:Mannose-Binding Protein-Associated Serine Proteases; D012697:Serine Endopeptidases; D000097604:Ficolins