Dectin-2 is a pattern recognition receptor for fungi that couples with the Fc receptor gamma chain to induce innate immune responses

J Biol Chem. 2006 Dec 15;281(50):38854-66. doi: 10.1074/jbc.M606542200. Epub 2006 Oct 18.

Abstract

Antigen presenting cells recognize pathogens via pattern recognition receptors (PRR), which upon ligation transduce intracellular signals that can induce innate immune responses. Because some C-type lectin-like receptors (e.g. dectin-1 and DCSIGN) were shown to act as PRR for particular microbes, we considered a similar role for dectin-2. Binding assays using soluble dectin-2 receptors showed the extracellular domain to bind preferentially to hyphal (rather than yeast/conidial) components of Candida albicans, Microsporum audouinii, and Trichophyton rubrum. Selective binding for hyphae was also observed using RAW macrophages expressing dectin-2, the ligation of which by hyphae or cross-linking with dectin-2-specific antibody led to protein tyrosine phosphorylation. Because dectin-2 lacks an intracellular signaling motif, we searched for a signal adaptor that permits it to transduce intracellular signals. First, we found that the Fc receptor gamma (FcRgamma) chain can bind to dectin-2. Second, ligation of dectin-2 on RAW cells induced tyrosine phosphorylation of FcRgamma, activation of NF-kappaB, internalization of a surrogate ligand, and up-regulated secretion of tumor necrosis factor alpha and interleukin-1 receptor antagonist. Finally, these dectin-2-induced events were blocked by PP2, an inhibitor of Src kinases that are mediators for FcRgamma chain-dependent signaling. We conclude that dectin-2 is a PRR for fungi that employs signaling through FcRgamma to induce innate immune responses.

MeSH terms

  • Animals
  • Base Sequence
  • Blotting, Western
  • Calcium / metabolism
  • Cell Line
  • DNA Primers
  • Fungi / immunology
  • Fungi / metabolism*
  • Immunity, Innate*
  • Immunoprecipitation
  • Interleukin 1 Receptor Antagonist Protein / biosynthesis
  • Lectins, C-Type / metabolism*
  • Mice
  • NF-kappa B / metabolism
  • Phosphorylation
  • Protein Binding
  • Receptors, Fc / metabolism*
  • Signal Transduction
  • Tumor Necrosis Factor-alpha / biosynthesis

Substances

  • DNA Primers
  • Interleukin 1 Receptor Antagonist Protein
  • Lectins, C-Type
  • NF-kappa B
  • Receptors, Fc
  • Tumor Necrosis Factor-alpha
  • dectin-2, mouse
  • Calcium