TICAM-1, an adaptor molecule that participates in Toll-like receptor 3–mediated interferon-β induction

Human Toll-like receptor (TLR) 3 recognizes double-stranded (ds) RNA and induces production of interferon (IFN)-β independent of the adaptor molecules MyD88 and TIRAP. Thus, another adaptor must exist that preferentially mediates TLR3-dependent production of IFN-β. We have identified an alternative adaptor, designated Toll-interleukin 1 receptor domain (TIR)-containing adaptor molecule (TICAM)-1, that can physically bind the TIR domain of TLR3 and activate the IFN-β promoter in response to poly(I):poly(C). Thus, dsRNA-TLR3–dependent production of IFN-β is mediated mainly by TICAM-1. This TICAM-1–dependent pathway may have a role in other TLR–IFN-β pathways, which form part of the MyD88-independent cellular immune response.