Adapter protein that plays a role in different signaling pathways including TLRs and IL-1 pathways or innate antiviral induction signaling. Plays a role in the activation of NF-kappa-B by forming a signal complex with TRAF6 and TAK1/MAP3K7 to activate TAK1/MAP3K7 leading to activation of IKKs (PubMed:25355951, PubMed:31281713). Once ubiquitinated, interacts with the dissociated RELA and NFKB1 proteins and translocates to the nucleus where it induces NF-kappa-B-dependent gene expression (PubMed:25355951). Plays a role in innate antiviral immune response by bridging the pattern recognition receptors RIGI and MDA5/IFIT1 to the MAVS complex at the mitochondrion (PubMed:25228397). Promotes proteolytic activation of MAP3K1. Involved in the BMP signaling pathway. Required for normal embryonic development (By similarity). ; As part of the MCIA complex, involved in the assembly of the mitochondrial complex I.