title: Dectin-1 and Dectin-2 in innate immunity against fungi.
abstract: Dectin-1 and Dectin-2 are type II transmembrane proteins of the C-type lectin family with single carbohydrate recognition domains (CRDs) in their extracellular region. They are expressed mainly in dendritic cells and macrophages. Dectin-1 recognizes β-glucans with its CRD and transduces signals through its immunoreceptor tyrosine-based activation motif (ITAM)-like motif in the cytoplasmic domain, whereas Dectin-2 recognizes α-mannans and transduces its signal through association with the ITAM-containing Fc receptor γ chain. Upon ligand binding, spleen tyrosine kinase is recruited to the ITAM and activates the caspase recruitment domain family member 9 (CARD9)-nuclear factor-κB axis, resulting in the activation of various genes including those encoding pro-inflammatory cytokines. Both β-glucans and α-mannans are major cell wall components of fungi including Candida albicans and Pneumocystis carinii. Recently, it was reported that Dectin-1 is important in protection against P. carinii by inducing reactive oxygen species, whereas both Dectin-1 and Dectin-2 play important roles in defense against C. albicans by preferentially inducing T(h)17 cell differentiation. In this review, we briefly revisit the structures, ligands, signal transduction and functional roles of Dectin-1 and Dectin-2 in host defense against fungal infection.
authors.affiliation: Department of Molecular Immunology, Medical Mycology Research Center, Chiba University, Chiba 260-8673, Japan.
authors.forename: Shinobu
authors.initials: S
authors.lastname: Saijo
authors.forename: Yoichiro
authors.initials: Y
authors.lastname: Iwakura
mesh_terms: D000818:Animals; D005658:Fungi / Q000276:immunology*; D006801:Humans; D007113:Immunity, Innate / Q000276:immunology*; D037181:Lectins, C-Type / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D008024:Ligands; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D009181:Mycoses / Q000276:immunology*; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D015398:Signal Transduction / Q000276:immunology; D000099181:Dectin-1
chemical_list: D037181:Lectins, C-Type; D008024:Ligands; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D000099181:Dectin-1; C445340:dectin-2, mouse