RING domain E3 ubiquitin (Ub) ligase; role in Ub-mediated degradation of non-stop proteins and translationally stalled ER membrane proteins; component of ribosome-bound RQC (ribosome quality control) complex; role in the turnover of stalled nascent chain polypeptides through lysine residues exposed by CAT (C-terminal alanine and threonine) tailing; degrades mRNA products lacking a termination codon; role in chromatin modification; mutations in mouse homolog Listerin elicit neurodegeneration