Mannose Associated Serine Protease 2 (MASP2)

MASP2 is a protein involved in the complement system. Mannose-binding lectin (MBL) is a serum component which participates in innate immunity by activating complement via a novel pathway. Human MBL forms complexes with two types of serine proteases termed MASP (MBL-associated serine protease). These two proteases, MASP1 and MASP2, are structurally similar to one another as well as to C1r and C1s. Together, MASP, C1r and C1s constitute a novel serine protease family. It is likely that human MASP1 is able to activate C3, while human MASP2 cleaves C4, although further functional studies are required to confirm this. Based on the analysis of MASP cDNA of vertebrates and ascidians, the MASP/C1r/C1s family can be classified into two groups.