Accepts ubiquitin from the E1 complex and catalyzes its covalent attachment to other proteins . In vitro catalyzes 'Lys-48'-linked polyubiquitination . Mediates the selective degradation of short-lived and abnormal proteins. Functions in the E6/E6-AP-induced ubiquitination of p53/TP53. Mediates ubiquitination of PEX5 and auto-ubiquitination of STUB1, TRAF6 and TRIM63/MURF1 (, ). Ubiquitinates STUB1-associated HSP90AB1 in vitro . Lacks inherent specificity for any particular lysine residue of ubiquitin . Essential for viral activation of IRF3 . Mediates polyubiquitination of CYP3A4 .
Subcellular locations: Cytoplasm
Ubiquitous. Up-regulated in livers of iron-overloaded patients with hereditary hemochromatosis.