E3 ubiquitin-protein ligase that mediates the polyubiquitination of lysine and cysteine residues on target proteins and is thereby implicated in the regulation of various signaling pathways including autophagy, innate immunity or DNA repair (PubMed:20064473, PubMed:31959741, PubMed:33608556). Inhibits TGF-beta signaling by triggering SMAD2 and TGFBR1 ubiquitination and proteasome-dependent degradation (PubMed:15496141). Downregulates autophagy and cell growth by ubiquitinating and reducing cellular ULK1 or ASCT2 levels (PubMed:28820317, PubMed:31959741). Promotes ubiquitination and internalization of various plasma membrane channels such as ENaC, SCN2A/Nav1.2, SCN3A/Nav1.3, SCN5A/Nav1.5, SCN9A/Nav1.7, SCN10A/Nav1.8, KCNA3/Kv1.3, KCNH2, EAAT1, KCNQ2/Kv7.2, KCNQ3/Kv7.3 or CLC5 (PubMed:26363003, PubMed:27445338). Promotes ubiquitination and degradation of SGK1 and TNK2. Ubiquitinates BRAT1 and this ubiquitination is enhanced in the presence of NDFIP1 (PubMed:25631046). Plays a role in dendrite formation by melanocytes (PubMed:23999003). Involved in the regulation of TOR signaling (PubMed:27694961). Ubiquitinates and regulates protein levels of NTRK1 once this one is activated by NGF (PubMed:27445338). Plays a role in antiviral innate immunity by catalyzing ‘Lys-29’-linked cysteine ubiquitination of TRAF3, resulting in enhanced ‘Lys-48’ and ‘Lys-63’-linked ubiquitination of TRAF3 (PubMed:33608556). Ubiquitinates TTYH2 and TTYH3 and regulates protein levels of TTYH2 (PubMed:18577513).
