Format

Send to

Choose Destination
J Exp Med. 2010 Apr 12;207(4):721-30. doi: 10.1084/jem.20091776. Epub 2010 Mar 15.

Selective control of type I IFN induction by the Rac activator DOCK2 during TLR-mediated plasmacytoid dendritic cell activation.

Author information

1
Division of Immunogenetics, Department of Immunobiology and Neuroscience, Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-8582, Japan.

Abstract

Plasmacytoid dendritic cells (pDCs) play a key role in antiviral immunity, but also contribute to the pathogenesis of certain autoimmune diseases, by producing large amounts of type I IFNs. Although activation of pDCs is triggered by engagement of nucleotide-sensing toll-like receptors (TLR) 7 and 9, type I IFN induction additionally requires IkappaB kinase (IKK) alpha-dependent activation of IFN regulatory factor (IRF) 7. However, the signaling pathway mediating IKK-alpha activation is poorly defined. We show that DOCK2, an atypical Rac activator, is essential for TLR7- and TLR9-mediated IFN-alpha induction in pDCs. We found that the exposure of pDCs to nucleic acid ligands induces Rac activation through a TLR-independent and DOCK2-dependent mechanism. Although this Rac activation was dispensable for induction of inflammatory cytokines, phosphorylation of IKK-alpha and nuclear translocation of IRF-7 were impaired in Dock2-deficient pDCs, resulting in selective loss of IFN-alpha induction. Similar results were obtained when a dominant-negative Rac mutant was expressed in wild-type pDCs. Thus, the DOCK2-Rac signaling pathway acts in parallel with TLR engagement to control IKK-alpha activation for type I IFN induction. Owing to its hematopoietic cell-specific expression, DOCK2 may serve as a therapeutic target for type I IFN-related autoimmune diseases.

PMID:
20231379
PMCID:
PMC2856018
DOI:
10.1084/jem.20091776
[Indexed for MEDLINE]
Free PMC Article

Publication type, MeSH terms, Substances

Publication type

MeSH terms

Substances

Supplemental Content

Full text links

Icon for HighWire Icon for PubMed Central
Loading ...
Support Center