C-type lectin (CTL)/C-type lectin-like (CTLD) domain; CLECT: C-type lectin (CTL)/C-type lectin-like (CTLD) domain; protein domains homologous to the carbohydrate-recognition domains (CRDs) of the C-type lectins. This group is chiefly comprised of eukaryotic CTLDs, but contains some, as yet functionally uncharacterized, bacterial CTLDs. Many CTLDs are calcium-dependent carbohydrate binding modules; other CTLDs bind protein ligands, lipids, and inorganic surfaces, including CaCO3 and ice. Animal C-type lectins are involved in such functions as extracellular matrix organization, endocytosis, complement activation, pathogen recognition, and cell-cell interactions. For example: mannose-binding lectin and lung surfactant proteins A and D bind carbohydrates on surfaces (e.g. pathogens, allergens, necrotic, and apoptotic cells) and mediate functions associated with killing and phagocytosis; P (platlet)-, E (endothelial)-, and L (leukocyte)- selectins (sels) mediate the initial attachment, tethering, and rolling of lymphocytes on inflamed vascular walls enabling subsequent lymphocyte adhesion and transmigration. CTLDs may bind a variety of carbohydrate ligands including mannose, N-acetylglucosamine, galactose, N-acetylgalactosamine, and fucose. Several CTLDs bind to protein ligands, and only some of these binding interactions are Ca2+-dependent; including the CTLDs of Coagulation Factors IX/X (IX/X) and Von Willebrand Factor (VWF) binding proteins, and natural killer cell receptors. C-type lectins, such as lithostathine, and some type II antifreeze glycoproteins function in a Ca2+-independent manner to bind inorganic surfaces. Many proteins in this group contain a single CTLD; these CTLDs associate with each other through several different surfaces to form dimers, trimers, or tetramers, from which ligand-binding sites project in different orientations. Various vertebrate type 1 transmembrane proteins including macrophage mannose receptor, endo180, phospholipase A2 receptor, and dendritic and epithelial cell receptor (DEC205) have extracellular domains containing 8 or more CTLDs; these CTLDs remain in the parent model. In some members (IX/X and VWF binding proteins), a loop extends to the adjoining domain to form a loop-swapped dimer. A similar conformation is seen in the macrophage mannose receptor CRD4's putative non-sugar bound form of the domain in the acid environment of the endosome. Lineage specific expansions of CTLDs have occurred in several animal lineages including Drosophila melanogaster and Caenorhabditis elegans; these CTLDs also remain in the parent model.

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gi 755516795 131 CPKDWRLFGSHCYLVPTvsSSASWNKSEENCSRMGAHLVVIQSQEEQ 177
Cdd:cd03590    1 CPTNWKSFQSSCYFFST--EKKSWEESRQFCEDMGAHLVIINSQEEQ 45

C-type lectin-like domain (CTLD) of the type found in human dendritic cell (DC)-specific intercellular adhesion molecule 3-grabbing non-integrin (DC-SIGN) and the related receptor, DC-SIGN receptor (DC-SIGNR); CLECT_DC-SIGN_like: C-type lectin-like domain (CTLD) of the type found in human dendritic cell (DC)-specific intercellular adhesion molecule 3-grabbing non-integrin (DC-SIGN) and the related receptor, DC-SIGN receptor (DC-SIGNR). This group also contains proteins similar to hepatic asialoglycoprotein receptor (ASGP-R) and langerin in human. These proteins are type II membrane proteins with a CTLD ectodomain. CTLD refers to a domain homologous to the carbohydrate-recognition domains (CRDs) of the C-type lectins. DC-SIGN is thought to mediate the initial contact between dendritic cells and resting T cells, and may also mediate the rolling of DCs on epithelium. DC-SIGN and DC-SIGNR bind to oligosaccharides present on human tissues, as well as, on pathogens including parasites, bacteria, and viruses. DC-SIGN and DC-SIGNR bind to HIV enhancing viral infection of T cells. DC-SIGN and DC-SIGNR are homotetrameric, and contain four CTLDs stabilized by a coiled coil of alpha helices. The hepatic ASGP-R is an endocytic recycling receptor which binds and internalizes desialylated glycoproteins having a terminal galactose or N-acetylgalactosamine residues on their N-linked carbohydrate chains, via the clathrin-coated pit mediated endocytic pathway, and delivers them to lysosomes for degradation. It has been proposed that glycoproteins bearing terminal Sia (sialic acid) alpha2, 6GalNAc and Sia alpha2, 6Gal are endogenous ligands for ASGP-R and that ASGP-R participates in regulating the relative concentration of serum glycoproteins bearing alpha 2,6-linked Sia. The human ASGP-R is a hetero-oligomer composed of two subunits, both of which are found within this group. Langerin is expressed in a subset of dendritic leukocytes, the Langerhans cells (LC). Langerin induces the formation of Birbeck Granules (BGs) and associates with these BGs following internalization. Langerin binds, in a calcium-dependent manner, to glyco-conjugates containing mannose and related sugars mediating their uptake and degradation. Langerin molecules oligomerize as trimers with three CTLDs held together by a coiled-coil of alpha helices.

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gi 755516795 131 CPKDWRLFGSHCYLVPTvsSSASWNKSEENCSRMGAHLVVIQSQEEQ 177
Cdd:cd03590    1 CPTNWKSFQSSCYFFST--EKKSWEESRQFCEDMGAHLVIINSQEEQ 45

Lectin C-type domain; This family includes both long and short form C-type

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gi 755516795  151 SASWNKSEENCSRMGAHLVVIQSQEEQ 177
Cdd:pfam00059   1 SKTWDEAREACRKLGGHLVSINSAEEL 27

C-type lectin-like domain (CTLD) of the type found in human dendritic cell (DC)-specific intercellular adhesion molecule 3-grabbing non-integrin (DC-SIGN) and the related receptor, DC-SIGN receptor (DC-SIGNR); CLECT_DC-SIGN_like: C-type lectin-like domain (CTLD) of the type found in human dendritic cell (DC)-specific intercellular adhesion molecule 3-grabbing non-integrin (DC-SIGN) and the related receptor, DC-SIGN receptor (DC-SIGNR). This group also contains proteins similar to hepatic asialoglycoprotein receptor (ASGP-R) and langerin in human. These proteins are type II membrane proteins with a CTLD ectodomain. CTLD refers to a domain homologous to the carbohydrate-recognition domains (CRDs) of the C-type lectins. DC-SIGN is thought to mediate the initial contact between dendritic cells and resting T cells, and may also mediate the rolling of DCs on epithelium. DC-SIGN and DC-SIGNR bind to oligosaccharides present on human tissues, as well as, on pathogens including parasites, bacteria, and viruses. DC-SIGN and DC-SIGNR bind to HIV enhancing viral infection of T cells. DC-SIGN and DC-SIGNR are homotetrameric, and contain four CTLDs stabilized by a coiled coil of alpha helices. The hepatic ASGP-R is an endocytic recycling receptor which binds and internalizes desialylated glycoproteins having a terminal galactose or N-acetylgalactosamine residues on their N-linked carbohydrate chains, via the clathrin-coated pit mediated endocytic pathway, and delivers them to lysosomes for degradation. It has been proposed that glycoproteins bearing terminal Sia (sialic acid) alpha2, 6GalNAc and Sia alpha2, 6Gal are endogenous ligands for ASGP-R and that ASGP-R participates in regulating the relative concentration of serum glycoproteins bearing alpha 2,6-linked Sia. The human ASGP-R is a hetero-oligomer composed of two subunits, both of which are found within this group. Langerin is expressed in a subset of dendritic leukocytes, the Langerhans cells (LC). Langerin induces the formation of Birbeck Granules (BGs) and associates with these BGs following internalization. Langerin binds, in a calcium-dependent manner, to glyco-conjugates containing mannose and related sugars mediating their uptake and degradation. Langerin molecules oligomerize as trimers with three CTLDs held together by a coiled-coil of alpha helices.

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gi 755516795 131 CPKDWRLFGSHCYLVPTvsSSASWNKSEENCSRMGAHLVVIQSQEEQ 177
Cdd:cd03590    1 CPTNWKSFQSSCYFFST--EKKSWEESRQFCEDMGAHLVIINSQEEQ 45

C-type lectin-like domain (CTLD) of the type found in natural killer cell receptors (NKRs); CLECT_NK_receptors_like: C-type lectin-like domain (CTLD) of the type found in natural killer cell receptors (NKRs), including proteins similar to oxidized low density lipoprotein (OxLDL) receptor (LOX-1), CD94, CD69, NKG2-A and -D, osteoclast inhibitory lectin (OCIL), dendritic cell-associated C-type lectin-1 (dectin-1), human myeloid inhibitory C-type lectin-like receptor (MICL), mast cell-associated functional antigen (MAFA), killer cell lectin-like receptors: subfamily F, member 1 (KLRF1) and subfamily B, member 1 (KLRB1), and lys49 receptors. CTLD refers to a domain homologous to the carbohydrate-recognition domains (CRDs) of the C-type lectins. NKRs are variously associated with activation or inhibition of natural killer (NK) cells. Activating NKRs stimulate cytolysis by NK cells of virally infected or transformed cells; inhibitory NKRs block cytolysis upon recognition of markers of healthy self cells. Most Lys49 receptors are inhibitory; some are stimulatory. OCIL inhibits NK cell function via binding to the receptor NKRP1D. Murine OCIL in addition to inhibiting NK cell function inhibits osteoclast differentiation. MAFA clusters with the type I Fc epsilon receptor (FcepsilonRI) and inhibits the mast cells secretory response to FcepsilonRI stimulus. CD72 is a negative regulator of B cell receptor signaling. NKG2D is an activating receptor for stress-induced antigens; human NKG2D ligands include the stress induced MHC-I homologs, MICA, MICB, and ULBP family of glycoproteins Several NKRs have a carbohydrate-binding capacity which is not mediated through calcium ions (e.g. OCIL binds a range of high molecular weight sulfated glycosaminoglycans including dextran sulfate, fucoidan, and gamma-carrageenan sugars). Dectin-1 binds fungal beta-glucans and in involved in the innate immune responses to fungal pathogens. MAFA binds saccharides having terminal alpha-D mannose residues in a calcium-dependent manner. LOX-1 is the major receptor for OxLDL in endothelial cells and thought to play a role in the pathology of atherosclerosis. Some NKRs exist as homodimers (e.g.Lys49, NKG2D, CD69, LOX-1) and some as heterodimers (e.g. CD94/NKG2A). Dectin-1 can function as a monomer in vitro.

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gi 755516795 131 CPKDWRLFGSHCYLVPTVSSSasWNKSEENCSRMGAHLVVIQSQEEQILAQ 181
Cdd:cd03593    1 CPKDWICYGNKCYYFSMEKKT--WNESKEACSSKNSSLLKIDDEEELEFLQ 49

C-type lectin-like domain (CTLD) of the type found in CEL-1 from Cucumaria echinata and Echinoidin from Anthocidaris crassispina; CLECT_CEL-1_like: C-type lectin-like domain (CTLD) of the type found in CEL-1 from Cucumaria echinata and Echinoidin from Anthocidaris crassispina. CTLD refers to a domain homologous to the carbohydrate-recognition domains (CRDs) of the C-type lectins. The CEL-1 CTLD binds three calcium ions and has a high specificity for N-acteylgalactosamine (GalNAc). CEL-1 exhibits strong cytotoxicity which is inhibited by GalNAc. This protein may play a role as a toxin defending against predation. Echinoidin is found in the coelomic fluid of the sea urchin and is specific for GalBeta1-3GalNAc. Echinoidin has a cell adhesive activity towards human cancer cells which is not mediated through the CTLD. Both CEL-1 and Echinoidin are multimeric proteins comprised of multiple dimers linked by disulfide bonds.

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gi 755516795 131 CPKDWRLFGSHCYLVptVSSSASWNKSEENC-----SRMGAHLVVIQSQEEQ 177
Cdd:cd03589    1 CPTFWTAFGGYCYRF--FGDRLTWEEAELRCrsfsiPGLIAHLVSIHSQEEN 50

C-type lectin-like domain (CTLD) of the type found in Human REG-1 (lithostathine), REG-4, and avian eggshell-specific proteins: ansocalcin, structhiocalcin-1(SCA-1), and -2(SCA-2); CLECT_REG-1_like: C-type lectin-like domain (CTLD) of the type found in Human REG-1 (lithostathine), REG-4, and avian eggshell-specific proteins: ansocalcin, structhiocalcin-1(SCA-1), and -2(SCA-2). CTLD refers to a domain homologous to the carbohydrate-recognition domains (CRDs) of the C-type lectins. REG-1 is a proliferating factor which participates in various kinds of tissue regeneration including pancreatic beta-cell regeneration, regeneration of intestinal mucosa, regeneration of motor neurons, and perhaps in tissue regeneration of damaged heart. REG-1 may play a role on the pathophysiology of Alzheimer's disease and in the development of gastric cancers. Its expression is correlated with reduced survival from early-stage colorectal cancer. REG-1 also binds and aggregates several bacterial strains from the intestinal flora and it has been suggested that it is involved in the control of the intestinal bacterial ecosystem. Rat lithostathine has calcium carbonate crystal inhibitor activity in vitro. REG-IV is unregulated in pancreatic, gastric, hepatocellular, and prostrate adenocarcinomas. REG-IV activates the EGF receptor/Akt/AP-1 signaling pathway in colorectal carcinoma. Ansocalcin, SCA-1 and -2 are found at high concentration in the calcified egg shell layer of goose and ostrich, respectively and tend to form aggregates. Ansocalcin nucleates calcite crystal aggregates in vitro.

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gi 755516795 131 CPKDWRLFGSHCYLVptVSSSASWNKSEENCSRM--GAHLVVIQSQEE 176
Cdd:cd03594    1 CPKGWLPYKGNCYGY--FRQPLSWSDAELFCQKYgpGAHLASIHSPAE 46