RING1 and YY1-binding protein (RYBP)

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, during development. PcG PRC1-like complex acts through chromatin remodeling and modification of histones; it mediates monoubiquitination of histone H2A'Lys-119', rendering chromatin heritably changed in its expressibility (PubMed:25519132).

Component of a PRC1-like complex that mediates monoubiquitination of histone H2A'Lys-119' on the X chromosome and is needed for normal silencing of a single copy of the X chromosome in XX females. Inhibits ubiquitination and subsequent degradation of TP53, and thus plays a role in regulating transcription of TP53 target genes (PubMed:19098711).