Search results for MASP1

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Reaction (2 results from a total of 2)

Identifier: R-HSA-166721
Species: Homo sapiens
Compartment: extracellular region, plasma membrane
The MBL polypeptide chain consists of a short N-terminal cysteine-rich region, a collagen-like region comprising 19 Gly-X-Y triplets, a 34-residue hydrophobic stretch, and a C-terminal C-type lectin domain. MBL monomers associate via their cysteine-rich and collagen-like regions to form homotrimers, and these in turn associate into oligomers. The predominant oligomers found in human serum contain three (MBL-I) or four (MBL-II) homotrimers (Fujita et al. 2004, Teillet et al. 2005). Extracellular MBL oligomers circulate as complexes with MASP1/2. In the presence of Ca2+, the carbohydrate recognition domain (CRD) of MBL binds carbohydrates with 3- and 4- OH groups in the pyranose ring, such as mannose and N-acetyl-D-glucosamine. Such motifs occur on the surfaces of viruses, bacteria, fungi and protozoa. The affinity of any one MBL binding site for a carbohydrate ligand is low, but interaction between multiple binding sites on an MBL oligomer and repetitive carbohydrate motifs on a target cell surface allow high-avidity binding. The specificity of the MBL binding site (it does not bind glucose or sialic acid) and the requirement for a repeated target motif may account for the failure of MBL to bind human glycoproteins under normal conditions (Petersen et al. 2001). This reaction in particular represents the interaction of MBL with bacterial mannose repeats.
Identifier: R-HSA-8852509
Species: Homo sapiens
Compartment: extracellular region, plasma membrane
Collectin kidney 1 (CL-K1, CL-11, COLEC11) (Keshi et al. 2006) forms disulfide-bridged stable heteromers with collectin liver 1 (CL-L1, COLEC10) (Otahani et al. 1999), with a ratio of one COLEC10 to two COLEC11 polypeptide chains. The majority of plasma COLEC11 was found in complex with COLEC10 (Henriksen et al. 2013). The resulting COLEC10:2xCOLEC11 heterocomplex, termred CL-LK, contains multiple Ca2+ -dependent carbohydrate-recognition domains (CRDs) and collagen-like regions, which allow high-avidity binding (KD ~10-9 M) to target cell surface carbohydrate patterns (Bajic et al. 2015); COLEC11 recognizes L-fucose and D-mannose and the disaccharide D-mannose(alpha1-2)-D-mannose (Keshi et al. 2006, Hansen et al. 2010, Selman & Hansen 2012, ). CL-LK can bind mannose-rich patterns on M. tuberculosis (Troegeler et al. 2015). The CL-LK complex was able to bind mannan-binding lectin-associated serine proteases (MASPs) in vitro with affinities in the nM range, and was associated with MASP1/3 and MASP2 in plasma. Upon binding to mannan or DNA in the presence of MASP2, the COLEC10:COLEC11 complex mediated deposition of C4b (Henriksen et al. 2013). Polymorphisms in the COLEC11 gene cause 3MC syndrome (Rooryck et al. 2011).
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