Ficolin-3 (FCN3)

Ficolin-3 (FCN3), also known as Hakata antigen, is a secreted pattern recognition glycoprotein that contains both a collagen-like domain and a fibrinogen-like domain[2][3][5]. It is primarily produced by hepatocytes and bile duct cells in the liver, but also in the lung. Ficolin-3 binds to specific carbohydrate structures on pathogens (such as N-acetylglucosamine and sialic acid) and subsequently activates the lectin pathway of the complement system via association with MASP2 (Mannose-binding lectin-associated serine protease 2)[1][2][4]. This leads to cleavage of complement factors C4 and C2, formation of C3 convertase, and ultimately assembly of the membrane attack complex (MAC), which lyses pathogen membranes and promotes phagocytosis[1][2][3][4][5]. FCN3 has also been implicated as a tumor suppressor in liver and lung cancers, where its expression is inversely correlated with tumor progression and prognosis, possibly through induction of necroptosis (kinase-mediated programmed cell death)[1][3].

Other names

Ficolin-3FCN3FCNHHAKA1collagen/fibrinogen domain-containing lectin 3 p35collagen/fibrinogen domain-containing protein 3Hakata antigenH-ficolinficolin (collagen/fibrinogen domain containing) 3

Activation of complement pathway via MASP2 binding, leading to membrane attack complex (MAC) formation and cell lysis[1][4] Induction of necroptosis via RIPK1/RIPK3/MLKL signaling[1]