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. Required for proper control of cellular levels of GMNN expression. Homodimer. Component of a PRC1-like complex (PubMed:12167701, PubMed:19636380, PubMed:21282530). Interacts with RNF2 and CBX7 (By similarity). Interacts with PHC2, PHC2 and BMI1 (By similarity). The disease is caused by variants affecting the gene represented in this entry. The hPRC-H complex purification reported by PubMed:12167701 probably presents a mixture of different PRC1-like complexes. Truncated N-terminus.