This gene encodes an adaptor protein containing a Toll/interleukin-1 receptor (TIR) homology domain, which is an intracellular signaling domain that mediates protein-protein interactions between the Toll-like receptors (TLRs) and signal-transduction components. This protein is involved in native immunity against invading pathogens. It specifically interacts with toll-like receptor 3, but not with other TLRs, and this association mediates dsRNA induction of interferon-beta through activation of nuclear factor kappa-B, during an antiviral immune response.