masp2 (protein) masp2 (protein) mannan-binding lectin serine protease 2 also known as mannose-binding protein-associated serine protease 2 (masp-2) is an enzyme that in humans is encoded by the masp2 gene. masp2available structurespdbortholog search: pdbe rcsb list of pdb id codes4fxg, 1q3x, 1szb, 1zjk, 3tvjidentifiersaliasesmasp2, map19, masp-2, masp1p1, smap, mannan binding lectin serine peptidase 2, mannan-binding lectin serine protease 2, mbl associated serine protease 2, map-2external idsomim: 605102 mgi: 1330832 homologene: 4819 genecards: masp2 gene location (human)chr.chromosome 1 (human)band1p36.22start11,026,523 bpend11,047,239 bpgene location (mouse)chr.chromosome 4 (mouse)band4|4 e2start148,687,011 bpend148,699,956 bprna expression patternbgeehumanmouse (ortholog)top expressed inright lobe of livercerebellar hemispherepancreatic ductal cellleft uterine tubemonocytemuscle of leggastrocnemius muscletibial nervegastric mucosaskin of abdomentop expressed inleft lobe of livergallbladdersuperior surface of tonguemorulasuperior frontal gyrusascending aortaaortic valveproximal tubulecerebellar cortexsupraoptic nucleusmore reference expression databiogpsn/agene ontologymolecular function calcium ion binding peptidase activity serine-type peptidase activity protein binding hydrolase activity calcium-dependent protein binding metal ion binding complement component c4b binding serine-type endopeptidase activity cellular component extracellular region extracellular exosome extracellular space biological process complement activation, lectin pathway proteolysis complement activation, classical pathway immune system process innate immune response complement activation sources:amigo / quickgoorthologsspecieshumanmouseentrez1074717175ensemblensg00000009724ensmusg00000028979uniproto00187q91wp0refseq (mrna)nm_139208nm_006610nm_001003893nm_010767refseq (protein)np_006601np_631947np_001003893np_034897location (ucsc)chr 1: 11.03 – 11.05 mbchr 4: 148.69 – 148.7 mbpubmed searchwikidataview/edit humanview/edit mouse function the ra-reactive factor (rarf) is a complement-dependent bactericidal factor that binds to the ra and r2 polysaccharides expressed by certain enterobacteria. 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. the encoded proteins are members of the trypsin family of peptidases. masp-2 is involved in the 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.