Dectin-2 is a pattern recognition receptor for fungi that couples with the Fc receptor gamma chain to induce innate immune responses.
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.
Sato
Kota
K
Department of Dermatology, the University of Texas Southwestern Medical Center and Dermatology Section (Medical Service), Dallas Veterans Affairs Medical Center, Dallas, TX 75390, USA.
Yang
Xiao-li
XL
Yudate
Tatsuo
T
Chung
Jin-Sung
JS
Wu
Jianming
J
Luby-Phelps
Kate
K
Kimberly
Robert P
RP
Underhill
David
D
Cruz
Ponciano D
PD
Ariizumi
Kiyoshi
K
D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D002118:Calcium / Q000378:metabolism; D002460:Cell Line; D017931:DNA Primers; D005658:Fungi / Q000276:immunology / Q000378:metabolism*; D007113:Immunity, Innate; D047468:Immunoprecipitation; D053590:Interleukin 1 Receptor Antagonist Protein / Q000096:biosynthesis; D037181:Lectins, C-Type / Q000378:metabolism*; D051379:Mice; D016328:NF-kappa B / Q000378:metabolism; D010766:Phosphorylation; D011485:Protein Binding; D011961:Receptors, Fc / Q000378:metabolism*; D015398:Signal Transduction; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis
D017931:DNA Primers; D053590:Interleukin 1 Receptor Antagonist Protein; D037181:Lectins, C-Type; D016328:NF-kappa B; D011961:Receptors, Fc; D014409:Tumor Necrosis Factor-alpha; C445340:dectin-2, mouse; D002118:Calcium