E3 ubiquitin-protein ligase that participates in multiple biological processes including cell survival, differentiation, apoptosis, and in particular, the innate immune response (PubMed:28747347, PubMed:31360105). Participates in the activation of interferon-gamma signaling by promoting proteasomal degradation of the repressor SOCS1 (PubMed:12163497). Plays a positive role in the TNFalpha and IL-1beta signaling pathways. Mechanistically, induces the 'Lys-63'-linked polyubiquitination of MAP3K7/TAK1 component leading to the activation of NF-kappa-B (By similarity). Modulates also STAT3 activity through negative regulation of PIAS3, either by degradation of PIAS3 through the ubiquitin-proteasome pathway or exclusion of PIAS3 from the nucleus (By similarity). Negatively regulates TLR3/4-mediated innate immune response by catalyzing 'Lys-6'- and 'Lys-33'-linked polyubiquitination of TICAM1 and thereby disrupting the TICAM1-TBK1 interaction (PubMed:28747347). S-ubiquitinyl-[E2 ubiquitin-conjugating enzyme]-L-cysteine + [acceptor protein]-L-lysine = [E2 ubiquitin-conjugating enzyme]-L-cysteine + N(6)-ubiquitinyl-[acceptor protein]-L-lysine. Protein modification; protein ubiquitination. Homodimer. Interacts with SOCS1 (via) SH2 domain and SOCS box. Interacts with HSP90AB1; prevents nucleus translocation of phosphorylated STAT3 and HSP90AB1 (PubMed:21689689). Interacts with MAP3K7/TAK1 (By similarity). Interacts with PIAS3 (By similarity). Interacts with TICAM1 (PubMed:28747347). High expression in heart, liver, and thymus. Expressed in embryonic CNS, kidney, lens and gut. At 10.5 and 12.5 dpc, expressed in the central nervous system. At 14.5 dpc, expressed in the eye (lens and inner neural layer of the retina), in the primitive glomeruli of the developing kidney, in the villi of the gut and in the dorsal root ganglia. The coiled coil domain is required for homodimerization. The region immediately C-terminal to the RING motif is sufficient to mediate the interaction with SOCS1. Mice are more susceptible to LPS and bacterial-induced death (PubMed:28747347). In addition, TRIM8 deletion plays a protective role in hepatocyte injury triggered by hepatic ischaemia/reperfusion (I/R) injury (PubMed:31360105). Belongs to the TRIM/RBCC family.