MDA-7

MASP2

MASP2, or Mannan-binding lectin serine protease 2, is a crucial enzyme in the lectin pathway of the complement system, which is part of the innate immune response. This enzyme plays a significant role in the activation of the complement system, which helps in opsonization, inflammation, and lysis of pathogens.

Structure

MASP2 is a serine protease that is structurally similar to other proteases in the complement system, such as C1r and C1s. It is composed of several domains, including a CUB domain, an EGF-like domain, two complement control protein (CCP) domains, and a serine protease domain. The serine protease domain is responsible for its enzymatic activity.

Function

MASP2 is activated when it binds to mannan-binding lectin (MBL) or ficolins that have attached to pathogen-associated molecular patterns (PAMPs) on the surface of microorganisms. Upon activation, MASP2 cleaves complement components C4 and C2, leading to the formation of the C3 convertase, C4b2a. This convertase then cleaves C3 into C3a and C3b, propagating the complement cascade.

Clinical Significance

Deficiencies or polymorphisms in MASP2 can lead to increased susceptibility to infections due to impaired complement activation. Conversely, overactivation of MASP2 has been implicated in certain inflammatory and autoimmune conditions. Research is ongoing to develop therapeutic interventions that target MASP2 for diseases where the lectin pathway is dysregulated.

Genetics

The MASP2 gene is located on chromosome 1p36.22. Variations in this gene can affect the levels and activity of the MASP2 protein, influencing an individual's immune response.

Research and Therapeutic Implications

Recent studies have focused on the role of MASP2 in various diseases, including systemic lupus erythematosus, rheumatoid arthritis, and ischemia-reperfusion injury. Inhibitors of MASP2 are being explored as potential treatments for conditions where excessive complement activation is detrimental.

Also see

• Complement system
• Mannan-binding lectin
• Serine protease
• Innate immune system