Alt. symbols: MASP1P1

Approved name: MBL associated serine protease 2
Alt. names: mannan-binding lectin serine protease 2, mannan-binding lectin serine peptidase 1 pseudogene 1, mannan-binding lectin serine protease 1 pseudogene 1

Location: 1p36.22: 11022009 - 11047239 (-)
Gene type: protein_coding, 17 transcripts.

Scores: LoFtool: 0.273000 | pLI: 0.00000000 | LOEUF: 1.146

HGNC: 6902

NCBI: 10747, RefSeq: NG_007289.2

Ensembl: ENSG00000009724.18

LRG_82 | Status: public

OMIM: 605102

Expression | ProteinAtlas

Gene Ontology (GO)

• Molecular function: serine-type endopeptidase activity [GO:0004252]
• Cell component: extracellular space [GO:0005615]
• Biological process: complement activation, lectin pathway [GO:0001867]

Normal function

MASP2 encodes a serum serine protease that plays an important role in the activation of the complement system via mannose-binding lectin (MBL), which recognizes various ligands expressed by a wide variety of microorganisms. After activation by auto-catalytic cleavage, it cleaves C2 and C4, leading to their activation and to the formation of C3 convertase.

Dysfunction and disease

MASP2 deficiency [MIM:613791] is an autosomal recessive condition classically defined as a MASP2 protein level of <100 ng/ml. This occurs in about 4% of Caucasians and up to 18% of some African populations. While some MASP2-deficient individuals may have an increased risk of infection or autoimmune disease, most are asymptomatic. Systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), and inflammatory bowel disease (IBD) are some of the autoimmune conditions linked to MASP2 variants (PMID : 11256742, 32677764, 31383674), while total MASP2 dysfunction has been proposed to be a major modifier of lung disease in cystic fibrosis patients (PMID: 17045845). Homozygosity for the D120G variant is one of the most common causes, though this is found only in Caucasians and Inuits from West-Greenland (heterozygous allele frequency 3.7-3.9%). Other ethnic-specific variants include a 4-residue tandem duplication found only in Chinese patients (gene frequency 0.26%) and the P126L and R99Q variants present only in Africans and Amerindians. Of note, homozygosity for some variants such as V377A or R99Q has been associated with normal enzyme activity, while P126L homozygosity has been reported to engender nonfunctional protein (PMID: 17252003). Thus far, copy number changes and missense, nonsense and frameshift mutations have all been reported. [Load More]