Role of ficolin in innate immunity and its molecular basis.
Ficolin is a multimeric protein consisting of an N-terminal collagen-like domain and a C-terminal fibrinogen-like domain. The structure is similar to mannose-binding lectin (MBL) and complement C1q owing to the collagen-like stalk. Accumulating data indicate that a key function of ficolin is to recognize the carbohydrate moieties on pathogens as a pattern-recognition molecule. Two or three kinds of ficolin have been identified in each species of mammals. They are similar but with some differences in the expression site, location site, ligand-binding specificity and ability to form complexes with MBL-associated serine proteases (MASPs). Like MBL, some ficolins are serum lectins and can form a complex with MASPs and small MBL-associated protein (sMAP). This complex activates the complement through "the lectin pathway". Our recent study suggests that ficolin acts through two distinct routes: the lectin pathway and a primitive opsonophagocytosis. All these observations suggest that ficolins function in clearance of non-self, based on their location sites and their molecular features.
Endo
Yuichi
Y
Department of Immunology, Fukushima Medical University School of Medicine, 1-Hikarigaoka, Fukushima 960-1295, Japan. yendo@fmu.ac.jp
Matsushita
Misao
M
Fujita
Teizo
T
D000818:Animals; D005091:Exons / Q000235:genetics; D006801:Humans; D007113:Immunity, Innate / Q000276:immunology*; D037102:Lectins / Q000737:chemistry / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D008024:Ligands; D000097604:Ficolins
D037102:Lectins; D008024:Ligands; D000097604:Ficolins