Collectin, C-type lectin-like domain (IPR033990)

Short name: Collectin_CTLD

Overlapping homologous superfamilies

Domain relationships


This entry represents the C-type lectin-like domain (CTLD) of the type found in human collectins including lung surfactant proteins A and D, mannose-binding lectin (MBL, also known as mannan-binding protein or MBP), and CL-L1 (collectin liver 1) [PMID: 16394659, PMID: 8155265]. CTLD refers to a domain, homologous to the carbohydrate-recognition domains (CRDs) of the C-type lectins [PMID: 16336259].

The CTLDs of these collectins bind carbohydrates on surfaces (e.g. pathogens, allergens, necrotic, or apoptotic cells) and mediate functions associated with killing and phagocytosis. MBPs recognize high mannose oligosaccharides in a calcium dependent manner, bind to a broad range of pathogens, and trigger cell killing by activating the complement pathway [PMID: 12887296, PMID: 11414367]. MBP also acts directly as an opsonin [PMID: 2469767]. SP-A and SP-D in addition to functioning as host defense components, are components of pulmonary surfactant which play a role in surfactant homeostasis [PMID: 16213021, PMID: 23441475]. Pulmonary surfactant is a phospholipid-protein complex which reduces the surface tension within the lungs. SP-A binds the major surfactant lipid: dipalmitoylphosphatidylcholine (DPPC). SP-D binds two minor components of surfactant that contain sugar moieties: glucosylceramide and phosphatidylinositol (PI). MBP and SP-A, -D monomers are homotrimers with an N-terminal collagen region and three CTLDs. Multiple homotrimeric units associate to form supramolecular complexes. MBL deficiency results in an increased susceptibility to a large number of different infections and to inflammatory disease [PMID: 22377282].

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.