title: Ubiquitin-specific proteases 7 and 11 modulate Polycomb regulation of the INK4a tumour suppressor.
abstract: An important facet of transcriptional repression by Polycomb repressive complex 1 (PRC1) is the mono-ubiquitination of histone H2A by the combined action of the Posterior sex combs (Psc) and Sex combs extra (Sce) proteins. Here, we report that two ubiquitin-specific proteases, USP7 and USP11, co-purify with human PRC1-type complexes through direct interactions with the Psc orthologues MEL18 and BMI1, and with other PRC1 components. Ablation of either USP7 or USP11 in primary human fibroblasts results in de-repression of the INK4a tumour suppressor accompanied by loss of PRC1 binding at the locus and a senescence-like proliferative arrest. Mechanistically, USP7 and USP11 regulate the ubiquitination status of the Psc and Sce proteins themselves, thereby affecting their turnover and abundance. Our results point to a novel function for USPs in the regulation and function of Polycomb complexes.
authors.affiliation: Cancer Research UK, London Research Institute, London, UK.
authors.forename: Goedele N
authors.initials: GN
authors.lastname: Maertens
authors.forename: Selma
authors.initials: S
authors.lastname: El Messaoudi-Aubert
authors.forename: Sarah
authors.initials: S
authors.lastname: Elderkin
authors.forename: Kevin
authors.initials: K
authors.lastname: Hiom
authors.forename: Gordon
authors.initials: G
authors.lastname: Peters
mesh_terms: D049109:Cell Proliferation; D002478:Cells, Cultured; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000378:metabolism*; D006657:Histones / Q000378:metabolism; D006801:Humans; D009687:Nuclear Proteins / Q000378:metabolism; D063150:Polycomb Repressive Complex 1; D063146:Polycomb-Group Proteins; D011485:Protein Binding; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D034622:RNA Interference; D012097:Repressor Proteins / Q000378:metabolism*; D013869:Thiolester Hydrolases / Q000235:genetics / Q000378:metabolism*; D043222:Ubiquitin Thiolesterase / Q000235:genetics / Q000378:metabolism*; D000076084:Ubiquitin-Specific Peptidase 7; D054875:Ubiquitination
chemical_list: C069077:BMI1 protein, human; D019941:Cyclin-Dependent Kinase Inhibitor p16; D006657:Histones; D009687:Nuclear Proteins; D063146:Polycomb-Group Proteins; D011518:Proto-Oncogene Proteins; D012097:Repressor Proteins; C101359:USP11 protein, human; D063150:Polycomb Repressive Complex 1; D013869:Thiolester Hydrolases; C464569:USP7 protein, human; D043222:Ubiquitin Thiolesterase; D000076084:Ubiquitin-Specific Peptidase 7