| Mannan-binding Lectin Pathway |
Website Links For Pathway |
Information AboutMannan-binding Lectin Pathway |
|
The Mannan-binding lectin pathway is homologous to the Classical Complement Pathway . The MBL pathway uses a protein similar to C1q of the classical pathway which binds to mannose residues as well as other sugars in a pattern that allows binding on multiple pathogens. MBL, produced by the liver, can initiate complement by binding to these pathogen surfaces. MBL is a 6 headed molecule that forms a complex with MASP-I (Mannan-binding lectin '''A'''ssociated '''S'''erine '''P'''rotease) and MASP-II, two protease zymogens. MASP-I and MASP-II are very similar to C1r and C1s of the Classical Pathway and are thought to have a common evolutionary ancestor. When MBL binds to a pathogen's phospholipid bilayer, MASP-I and MASP-II are activated to cleave C4 and C2 into C4a, C4b, C2a, and C2b. C4b and C2b combine on the pathogen's surface forming C3 convertase (C4bC2b), while C4a and C2a act as chemoattractants. NOTE: It has been found that people deficient in MBL experience a substantial increase in infections during the early years of childhood. |
|
|