E3 ubiquitin-protein ligase that mediates ubiquitination and subsequent proteasomal degradation of target proteins (PubMed:28351989, PubMed:32786047). E3 ubiquitin ligases accept ubiquitin from an E2 ubiquitin-conjugating enzyme in the form of a thioester and then directly transfers the ubiquitin to targeted substrates (PubMed:28351989, PubMed:32786047). It probably triggers the ubiquitin-mediated degradation of different substrates (PubMed:28351989, PubMed:32786047). Mediates the proteasomal-dependent degradation of ATG6, a component of the autophagosome complex (PubMed:28351989). Requires TRAF1A/MUSE14 and TRAF1B/MUSE13 to target ATG6 for ubiquitination and subsequent regulation of autophagosome assembly (PubMed:28351989). Modulates directly the ubiquitination and proteasomal-dependent degradation of FREE1, a component of the ESCRT-I complex (PubMed:32786047, PubMed:32753431). Modulates directly the ubiquitination and proteasomal-dependent degradation of ELC/VPS23A, a component of the ESCRT-I complex (PubMed:32753431). 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 RAP2-2 (PubMed:17873090). Interacts with SINAT6 (PubMed:24350984). Interacts with ATG6 and TRAF1A (PubMed:28351989). Interacts with WAV3 (PubMed:22122664). Interacts with FREE1 (PubMed:32786047, PubMed:32753431). Interacts with ELC/VPS23A (PubMed:32753431). Induced by drought stress, salt stress, osmotic shock and abscisic acid (ABA). The RING-type zinc finger domain is essential for ubiquitin ligase activity. The SBD domain (substrate-binding domain) mediates the homodimerization and the interaction with substrate proteins. It is related to the TRAF family. No visible phenotype, may be due to the existence of 4 homologous proteins. May be due to intron retention. Belongs to the SINA (Seven in absentia) family.