E3 ubiquitin-protein ligase that mediates monoubiquitination of 'Lys-119' of histone H2A, thereby playing a central role in histone code and gene regulation. H2A 'Lys-119' ubiquitination gives a specific tag for epigenetic transcriptional repression and participates in X chromosome inactivation of female mammals. May be involved in the initiation of both imprinted and random X inactivation. Essential 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, rendering chromatin heritably changed in its expressibility. E3 ubiquitin- protein ligase activity is enhanced by BMI1/PCGF4. Acts as the main E3 ubiquitin ligase on histone H2A of the PRC1 complex, while RING1 may rather act as a modulator of RNF2/RING2 activity. Component of chromatin-associated Polycomb (PcG) complexes. Part of the E2F6.com-1 complex in G0 phase composed of E2F6, MGA, MAX, TFDP1, CBX3, BAT8, EUHMTASE1, RING1, RNF2/RING2, MBLR, L3MBTL2 and YAF2. Component of a PRC1-like complex. Component of some MLL1/MLL complex, at least composed of the core components MLL, ASH2L, HCFC1/HCF1, WDR5 and RBBP5, as well as the facultative components C17orf49, CHD8, E2F6, HSP70, INO80C, KANSL1, LAS1L, MAX, MCRS1, MGA, MYST1/MOF, PELP1, PHF20, PRP31, RING2, RUVB1/TIP49A, RUVB2/TIP49B, SENP3, TAF1, TAF4, TAF6, TAF7, TAF9 and TEX10. Interacts with RYBP, HIP2 and TFCP2. Association to the chromosomal DNA is cell-cycle dependent. Component of repressive BCOR complex containing Polycomb group subcomplex at least composed of RYBP, PCGF1, BCOR and RING1. Interacts with Interacts with PCGF2, CBX4, CBX6, CBX7 and CBX8. Interacts with CBX2, BMI and PHC2. Interacts with RYBP, HIP2 and TFCP2. Note: This description may include information from UniProtKB.
Alt. Names/Synonyms: BAP-1; BAP1; DING; E3 ubiquitin-protein ligase RING2; HIP2-interacting protein 3; HIPI3; Huntingtin-interacting protein 2-interacting protein 3; Protein DinG; RING finger protein 1B; RING finger protein 2; RING finger protein BAP-1; RING1B; RING2; RNF2