MASP2

Mannan-binding lectin-associated serine protease 2 (MASP-2) is a member of the lectin pathway of complement and is one of two splice products from the MASP2 gene. The protein is secreted from the liver as a zymogenic protein consisting of 671 residues and circulates at a concentration of approximately 0.41 μg/mL in the serum. MASP-2 is associated with pattern-recognition molecules as a homodimer that is activated by MASP-1 when bound to an activating surface resulting in an A-chain and a B-chain linked by a disulphide bond. MASP-2 is also capable of autoactivating. Activated MASP-2 cleaves C2 and C4, which leads to formation of the C3 convertase, C4b2a, and activation of complement.