Structural highlights
Function
BMI1_HUMAN 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. In the PRC1 complex, it is required to stimulate the E3 ubiquitin-protein ligase activity of RNF2/RING2.[1] [2] [3]
Publication Abstract from PubMed
Histone H2A monoubiquitination (H2Aub1) by the PRC1 subunit RING1B entails a positive feedback loop, mediated by the RING1B-interacting protein RYBP. We uncover that human RYBP-PRC1 binds unmodified nucleosomes via RING1B but H2Aub1-modified nucleosomes via RYBP. RYBP interactions with both ubiquitin and the nucleosome acidic patch create the high binding affinity that favors RYBP- over RING1B-directed PRC1 binding to H2Aub1-modified nucleosomes; this enables RING1B to monoubiquitinate H2A in neighboring unmodified nucleosomes.
Structural basis of the histone ubiquitination read-write mechanism of RYBP-PRC1.,Ciapponi M, Karlukova E, Schkolziger S, Benda C, Muller J Nat Struct Mol Biol. 2024 Jul;31(7):1023-1027. doi: 10.1038/s41594-024-01258-x. , Epub 2024 Mar 25. PMID:38528151[4]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Cao R, Tsukada Y, Zhang Y. Role of Bmi-1 and Ring1A in H2A ubiquitylation and Hox gene silencing. Mol Cell. 2005 Dec 22;20(6):845-54. PMID:16359901 doi:10.1016/j.molcel.2005.12.002
- ↑ Chagraoui J, Niessen SL, Lessard J, Girard S, Coulombe P, Sauvageau M, Meloche S, Sauvageau G. E4F1: a novel candidate factor for mediating BMI1 function in primitive hematopoietic cells. Genes Dev. 2006 Aug 1;20(15):2110-20. PMID:16882984 doi:http://dx.doi.org/20/15/2110
- ↑ Li Z, Cao R, Wang M, Myers MP, Zhang Y, Xu RM. Structure of a Bmi-1-Ring1B polycomb group ubiquitin ligase complex. J Biol Chem. 2006 Jul 21;281(29):20643-9. Epub 2006 May 18. PMID:16714294 doi:10.1074/jbc.M602461200
- ↑ Ciapponi M, Karlukova E, Schkölziger S, Benda C, Müller J. Structural basis of the histone ubiquitination read-write mechanism of RYBP-PRC1. Nat Struct Mol Biol. 2024 Jul;31(7):1023-1027. PMID:38528151 doi:10.1038/s41594-024-01258-x
