CBX4

The polyhistidine repeat may act as a targeting signal to nuclear speckles.

E3 SUMO-protein ligase which facilitates SUMO1 conjugation by UBE2I (PubMed:12679040). Involved in the sumoylation of HNRNPK, a p53/TP53 transcriptional coactivator, hence indirectly regulates p53/TP53 transcriptional activation resulting in p21/CDKN1A expression. Monosumoylates ZNF131 (PubMed:22825850).

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 (PubMed:12167701, PubMed:19636380, PubMed:21282530). 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:12167701, PubMed:19636380, PubMed:21282530). Binds to histone H3 trimethylated at 'Lys-9' (H3K9me3) (By similarity). Plays a role in the lineage differentiation of the germ layers in embryonic development (By similarity).

Protein modification; protein sumoylation.

Ubiquitinated. Ubiquitination regulates the function of the Polycomb group (PcG) multiprotein PRC1-like complex. Deubiquitinated by USP26.

Phosphorylated on Thr-497 by HIPK2 upon DNA damage. This phosphorylation stimulates E3 SUMO-protein ligase activity and promotes sumoylation on Lys-494, as well as sumoylation of other target proteins, such as HNRNPK.

Ubiquitous.

• Nucleus
• Nucleus speckle
• Localization to nuclear polycomb bodies is required for ZNF131 sumoylation (PubMed:22467880). Localized in distinct foci on chromatin (PubMed:18927235).

E3 SUMO-protein ligase CBX4, Chromobox protein homolog 4, Polycomb 2 homolog, Pc2, hPc2, CBX4

• entrezGene:8535
• omim:603079
• swissprot:O00257

Proteins

Epigenetics

61368Da