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Structural basis of the histone ubiquitination read-write mechanism of RYBP-PRC1.

ABSTRACT: 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.

SUBMITTER: Ciapponi M

PROVIDER: S-EPMC11257959 | biostudies-literature | 2024 Jul

REPOSITORIES: biostudies-literature

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Structural basis of the histone ubiquitination read-write mechanism of RYBP-PRC1.

Ciapponi Maria M Karlukova Elena E Schkölziger Sven S Benda Christian C Müller Jürg J

Nature structural & molecular biology 20240325 7

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 ne ...[more]

PMID: 38528151

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