Alternate splicing of this gene results in two transcript variants encoding two RARF components that are involved in the mannan-binding lectin pathway of complement activation.

The longer isoform is cleaved into two chains which form a heterodimer linked by a disulfide bond.

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.

This article incorporates text from the United States National Library of Medicine, which is in the public domain.