Polycomb group RING finger protein 5 (Pcgf5)

Component of a Polycomb group (PcG) multiprotein PRC1- like complex, a complex course necessary to maintain the transcriptionally repressive state of many genes, including Hox genes, during 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 (PubMed:27136092, PubMed:28596365).

Within the PRC1-like complex, regulates RNF2 ubiquitin ligase activity (By similarity). Plays a redundant role with PCGF3 as part of a PRC1-like complex that mediates monoubiquitination of histone H2A'Lys-119' on the X chromosome and is required for normal silencing of a single copy of the X chromosome in XX females (PubMed:28596365).