The C-type lectin superfamily in the immune system.
Protein-carbohydrate interactions serve multiple functions in the immune system. Many animal lectins (sugar-binding proteins) mediate both pathogen recognition and cell-cell interactions using structurally related Ca(2+)-dependent carbohydrate-recognition domains (C-type CRDs). Pathogen recognition by soluble collections such as serum mannose-binding protein and pulmonary surfactant proteins, and also the macrophage cell-surface mannose receptor, is effected by binding of terminal monosaccharide residues characteristic of bacterial and fungal cell surfaces. The broad selectivity of the monosaccharide-binding site and the geometrical arrangement of multiple CRDs in the intact lectins explains the ability of the proteins to mediate discrimination between self and non-self. In contrast, the much narrower binding specificity of selectin cell adhesion molecules results from an extended binding site within a single CRD. Other proteins, particularly receptors on the surface of natural killer cells, contain C-type lectin-like domains (CTLDs) that are evolutionarily divergent from the C-type lectins and which would be predicted to function through different mechanisms.
Department of Structural Biology, Stanford University School of Medicine, California, USA. weis@fucose.stanford.edu
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D000595:Amino Acid Sequence; D000818:Animals; D002118:Calcium; D002352:Carrier Proteins / Q000737:chemistry / Q000378:metabolism; D037222:Collectins; D006801:Humans; D007107:Immune System / Q000378:metabolism; D007694:Killer Cells, Natural / Q000378:metabolism; D037102:Lectins / Q000737:chemistry* / Q000378:metabolism; D037181:Lectins, C-Type; D000090323:Mannose Receptor; D037241:Mannose-Binding Lectins; D008969:Molecular Sequence Data; D011487:Protein Conformation; D011956:Receptors, Cell Surface / Q000737:chemistry / Q000378:metabolism; D011971:Receptors, Immunologic / Q000737:chemistry; D019087:Selectins / Q000378:metabolism
D002352:Carrier Proteins; D037222:Collectins; D037102:Lectins; D037181:Lectins, C-Type; D000090323:Mannose Receptor; D037241:Mannose-Binding Lectins; D011956:Receptors, Cell Surface; D011971:Receptors, Immunologic; D019087:Selectins; D002118:Calcium