Component of a Polycomb group (PcG) multiprotein PRC1-like complex, a complex class required to maintain the transcriptionally repressive state of many genes, including Hox genes, throughout development. PcG PRC1 complex acts via chromatin remodeling and modification of histones; it mediates monoubiquitination of histone H2A 'Lys-119', rendering chromatin heritably changed in its expressibility (PubMed:15386022, PubMed:16359901, PubMed:26151332, PubMed:16714294, PubMed:21772249, PubMed:25355358, PubMed:27827373). The complex composed of RNF2, UB2D3 and BMI1 binds nucleosomes, and has activity only with nucleosomal histone H2A (PubMed:21772249, PubMed:25355358). In the PRC1-like complex, regulates the E3 ubiquitin-protein ligase activity of RNF2/RING2 (PubMed:15386022, PubMed:26151332, PubMed:21772249). Component of a PRC1-like complex (PubMed:12167701, PubMed:15386022, PubMed:19636380, PubMed:21282530, PubMed:26151332, PubMed:21772249, PubMed:25355358). Identified in a PRC1-like HPRC-H complex with CBX2, CBX4, CBX8, PHC1, PHC2, PHC3 RING1 and RNF2 (PubMed:12167701). Interacts with RNF2/RING2 (PubMed:16714294, PubMed:21772249, PubMed:25355358). Interacts with RING1 (By similarity). Part of a complex that contains RNF2, UB2D3 and BMI1, where RNF2 and BMI1 form a tight heterodimer, and UB2D3 interacts only with RNF2 (PubMed:21772249, PubMed:25355358). The complex composed of RNF2, UB2D3 and BMI1 binds nucleosomes, and has activity only with nucleosomal histone H2A (PubMed:21772249, PubMed:25355358). Interacts with CBX7 and CBX8 (PubMed:19636380). Interacts with SPOP (PubMed:15897469). Part of a complex consisting of BMI1, CUL3 and SPOP (PubMed:15897469). Interacts with E4F1 (PubMed:16882984). Interacts with PHC2 (PubMed:9121482, PubMed:9199346, PubMed:27827373). Interacts with zinc finger protein ZNF277 (By similarity). May be part of a complex including at least ZNF277, BMI1 and RNF2/RING2 (By similarity). Down-regulated by oxidative stress. Monoubiquitinated (By similarity). May be polyubiquitinated; which does not lead to proteasomal degradation. The hPRC-H complex purification reported by PubMed:12167701 probably presents a mixture of different PRC1-like complexes.