Antigen-presenting cells (APCs) including dendritic cells (DCs) play critical roles in the initiation of immune response and maintenance of immune tolerance.Recognition of the invading pathogens via pattern-recognition receptors will trigger signaling cascades in APCs, leading to production of inflammatory cytokines and interferon (IFN).Inappropriate activation of innate signaling may cause excessive inflammation and autoimmune diseases.Thus the innate signaling needs to be strictly regulated to avoid harmful immunopathology.