E3 ubiquitin-protein ligase required to prevent centriole reduplication (By similarity). Probably acts by ubiquitinating positive regulators of centriole reduplication (By similarity). Mediates monoubiquitination of 'Lys-119' of histone H2A (H2AK119Ub), a specific tag for epigenetic transcriptional repression: associates with some Polycomb group (PcG) multiprotein PRC2-like complex and mediates repression of target genes (PubMed:25470042). 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. Associates with the PRC2/EED-EZH2 complex. Found in vesicles of the peroxisome. Aggregates as aggresomes, a perinuclear region where certain misfolded or aggregated proteins are sequestered for proteasomal degradation. Highly expressed in testis and brain. In embryonic tissues, expressed in epithelia, including ducts of the developing pancreas, epithelium of the midgut and nasal epithelium. In adult, detected in the central and peripheral nervous systems, including enteric ganglia, retina and the adrenal medulla (at protein level). Auto-ubiquitinated. Belongs to the TRIM/RBCC family.