Mannose-binding protein C (MBL2) is a calcium-dependent lectin involved in innate immune defence. It binds to oligosaccharides (mannose, fucose and N-acetylglucosamine) on the surface of micro-organisms and initiates complement activation of the lectin pathway []. It also binds to late apoptotic cells, enabling their uptake by macrophages []. MBL2 forms a homotrimer []which then binds to mannan-binding lectin-associated serine peptidases, leading to their activation and cleavage of complement components C2 and C4 to form the C3/C5 convertase [, ]. MBL2 expressed on the brush border epithelial cells of kidney-proximal tubules interacts with meprin precursors, preventing activation []. The tertiary structure of MBL2 has been solved, and the protein contains a collagen-like and a C-typelectin domain [].
