E3 ubiquitin-protein ligase that promotes the ubiquitination of various substrates (PubMed:23645206, PubMed:25165885). In turn, participates in the regulation of many biological processes including cell cycle, apoptosis, osteoclastogenesis as well as innate or adaptive immunity (PubMed:25165885, PubMed:28708287). Acts as negative regulator of NF-kappa-B-dependent transcription by promoting the ubiquitination and stabilization of the NF-kappa-B inhibitor TNFAIP3 (PubMed:25165885). May promote the ubiquitination of TRAF6 as well (PubMed:28708287). Acts also as a negative regulator of T-cell activation (PubMed:25165885). Inhibits cellular dsRNA responses and interferon production by targeting MAVS component for proteasomal degradation (PubMed:25165885). Ubiquitinates the CDK inhibitor CDKN1A leading to its degradationand probably also CDKN1B and CDKN1C (PubMed:23645206). This activity stimulates cell cycle G1-to-S phase transition and suppresses cellular senescence. May play a role in spermatogenesis.