Isoform 1 acts as an E3 ubiquitin ligase, which accepts ubiquitin from specific E2 ubiquitin-conjugating enzymes, and then transfers it to substrates promoting their degradation by the proteasome. Promotes degradation of TRAF3, TLR4 and TLR9. Contributes to the regulation of antiviral responses. Down-regulates activation of NF-kappa-B, IRF3 activation and IFNB production. Isoform 3 inhibits TNF and IL-1 mediated activation of NF-kappa-B. Promotes TNF and RIP mediated apoptosis. 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. Interacts with UBE2L3 and to some extent with UBE2L6. Interacts with TRAF3, TLR3, TLR4, TLR5 and TLR9. Isoform 3/ZIN binds RIPK1. (Microbial infection) Isoform 3/ZIN binds RIPK1 and HIV Vif. Ubiquitous, with the highest levels of expression in testis and peripheral blood leukocytes. The RING-type zinc finger domain mediates binding to an E2 ubiquitin-conjugating enzyme. Auto-ubiquitinated. The disease is caused by variants affecting the gene represented in this entry. 4 different alternatively spliced mRNAs code for this protein isoform. Truncated N-terminus.