MASP2 (protein)

Mannan-binding lectin serine protease 2 also known as mannose-binding protein-associated serine protease 2 (MASP-2) is an is_associated_with::enzyme that in humans is encoded by the MASP2 is_associated_with::gene.

Function
The Ra-reactive factor (RARF) is a complement-dependent bactericidal factor that binds to the Ra and R2 is_associated_with::polysaccharides expressed by certain is_associated_with::enterobacteria. Alternate splicing of this gene results in two transcript variants encoding two RARF components that are involved in the is_associated_with::mannan-binding is_associated_with::lectin pathway of complement activation. The longer isoform is cleaved into two chains which form a heterodimer linked by a is_associated_with::disulfide bond. The encoded proteins are members of the is_associated_with::trypsin family of peptidases.

MASP-2 is involved in the is_associated_with::complement system. MASP-2 is very similar to the C1s molecule, of the classical complement pathway, and they are thought to have a common evolutionary ancestor. When the carbohydrate-recognising heads of MBL bind to specifically arranged mannose residues on the surface of a pathogen, MASP-2 is activated to cleave complement components C4 and C2 into C4a, C4b, C2a, and C2b.