MASP2 (protein)

MASP2 is a protein that in humans is encoded by the MASP2 gene. It is a component of the lectin pathway of the complement system, where it functions as a serine protease. MASP2 is crucial for the activation of the complement system and plays a vital role in the immune system.

Structure

The MASP2 protein is a serine protease that is structurally similar to C1s and C2, proteins involved in the classical pathway of the complement system. It consists of a CUB (C1r/C1s, Uegf, Bmp1) domain, an EGF (epidermal growth factor)-like domain, two complement control protein (CCP) modules, and a serine protease domain.

Function

MASP2 is a component of the lectin pathway of the complement system, which is activated by the binding of mannose-binding lectin (MBL) or ficolins to pathogen surfaces. Upon binding, MASP2 cleaves complement component 4 (C4) and complement component 2 (C2) to form the C3 convertase, C4b2a. This leads to the activation of the complement system, which plays a crucial role in the immune response against pathogens.

Clinical significance

Mutations in the MASP2 gene can lead to MASP2 deficiency, a condition characterized by increased susceptibility to infections. In addition, some studies suggest that MASP2 may be involved in the pathogenesis of certain autoimmune diseases, such as rheumatoid arthritis and systemic lupus erythematosus.

See also

• Complement system
• Lectin pathway
• Serine protease
• Immune system