E3 SUMO-protein ligase which facilitates SUMO1 conjugation by UBE2I. Component of the Polycomb group (PcG) multiprotein PRC1 complex, a complex 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.
Protein modification; protein sumoylation.
Contains 1 chromo domain.
Phosphorylated on Thr-497 by HIPK2 upon DNA damage; which enhances E3 SUMO-protein ligase activity and promotes sumoylation on Lys-494.