title: The polycomb protein Pc2 is a SUMO E3.
abstract: Polycomb group (PcG) proteins form large multimeric complexes (PcG bodies) which are involved in the stable repression of gene expression. The human PcG protein, Pc2, has been shown to recruit the transcriptional corepressor, CtBP, to PcG bodies. We show that CtBP is sumoylated at a single lysine. In vitro, CtBP sumoylation minimally requires the SUMO E1 and E2 (Ubc9) and SUMO-1. However, Pc2 dramatically enhances CtBP sumoylation. In vivo, this is likely due to the ability of Pc2 to recruit both CtBP and Ubc9 to PcG bodies, thereby bringing together substrate and E2, and stimulating the transfer of SUMO to CtBP. These results demonstrate that Pc2 is a SUMO E3, and suggest that PcG bodies may be sumoylation centers.
authors.affiliation: Department of Biochemistry and Molecular Genetics, Center for Cell Signaling, University of Virginia, Charlottesville, VA 22908, USA.
authors.forename: Michael H
authors.initials: MH
authors.lastname: Kagey
authors.forename: Tiffany A
authors.initials: TA
authors.lastname: Melhuish
authors.forename: David
authors.initials: D
authors.lastname: Wotton
mesh_terms: D000429:Alcohol Oxidoreductases; D000818:Animals; D019556:COS Cells; D002451:Cell Compartmentation / Q000235:genetics; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005057:Eukaryotic Cells / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D008025:Ligases / Q000235:genetics / Q000378:metabolism*; D008239:Lysine / Q000235:genetics / Q000378:metabolism; D046911:Macromolecular Substances; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D063146:Polycomb-Group Proteins; D021381:Protein Transport / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D025841:Small Ubiquitin-Related Modifier Proteins / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic / Q000235:genetics*; D025801:Ubiquitin / Q000235:genetics / Q000378:metabolism; D044763:Ubiquitin-Conjugating Enzymes; D044767:Ubiquitin-Protein Ligases; D000098843:Ubiquitin-Conjugating Enzyme UBC9
chemical_list: D004268:DNA-Binding Proteins; D046911:Macromolecular Substances; D010750:Phosphoproteins; D063146:Polycomb-Group Proteins; D012097:Repressor Proteins; D025841:Small Ubiquitin-Related Modifier Proteins; D025801:Ubiquitin; D000429:Alcohol Oxidoreductases; C096794:C-terminal binding protein; D044763:Ubiquitin-Conjugating Enzymes; D044767:Ubiquitin-Protein Ligases; D008025:Ligases; C570427:CBX4 protein, human; D000098843:Ubiquitin-Conjugating Enzyme UBC9; D008239:Lysine