title: NIPP1 maintains EZH2 phosphorylation and promoter occupancy at proliferation-related target genes.
abstract: The histone methyltransferase EZH2 regulates cell proliferation and differentiation by silencing Polycomb group target genes. NIPP1, a nuclear regulator of serine/threonine protein phosphatase 1 (PP1), has been implicated in the regulation of EZH2 occupancy at target loci, but the underlying mechanism is not understood. Here, we demonstrate that the phosphorylation of EZH2 by cyclin-dependent kinases at Thr416 creates a docking site for the ForkHead-associated domain of NIPP1. Recruited NIPP1 enables the net phosphorylation of EZH2 by inhibiting its dephosphorylation by PP1. Accordingly, a NIPP1-binding mutant of EZH2 is hypophosphorylated, and the knockdown of NIPP1 results in a reduced phosphorylation of endogenous EZH2. Conversely, the loss of PP1 is associated with a hyperphosphorylation of EZH2. A genome-wide promoter-binding profiling in HeLa cells revealed that the NIPP1-binding mutant shows a deficient association with about a third of the Polycomb target genes, and these are enriched for functions in proliferation. Our data identify PP1 as an EZH2 phosphatase and demonstrate that the phosphorylation-regulated association of EZH2 with proliferation-related targets depends on associated NIPP1.
authors.affiliation: Laboratory of Biosignaling & Therapeutics, Department of Cellular and Molecular Medicine, KU Leuven, B-3000 Leuven, Belgium.
authors.forename: Nikki
authors.initials: N
authors.lastname: Minnebo
authors.forename: Janina
authors.initials: J
authors.lastname: Görnemann
authors.forename: Nichole
authors.initials: N
authors.lastname: O'Connell
authors.forename: Nele
authors.initials: N
authors.lastname: Van Dessel
authors.forename: Rita
authors.initials: R
authors.lastname: Derua
authors.forename: Marit Willemijn
authors.initials: MW
authors.lastname: Vermunt
authors.forename: Rebecca
authors.initials: R
authors.lastname: Page
authors.forename: Monique
authors.initials: M
authors.lastname: Beullens
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Peti
authors.forename: Aleyde
authors.initials: A
authors.lastname: Van Eynde
authors.forename: Mathieu
authors.initials: M
authors.lastname: Bollen
mesh_terms: D000818:Animals; D049109:Cell Proliferation; D004722:Endoribonucleases / Q000737:chemistry / Q000378:metabolism*; D000071221:Enhancer of Zeste Homolog 2 Protein; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D008958:Models, Molecular; D010749:Phosphoprotein Phosphatases / Q000737:chemistry / Q000378:metabolism*; D010766:Phosphorylation; D063151:Polycomb Repressive Complex 2 / Q000737:chemistry / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D054730:Protein Interaction Domains and Motifs; D054645:Protein Phosphatase 1 / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D013912:Threonine / Q000378:metabolism
chemical_list: D016601:RNA-Binding Proteins; D013912:Threonine; C498409:EZH2 protein, human; D000071221:Enhancer of Zeste Homolog 2 Protein; C498410:Ezh2 protein, mouse; D063151:Polycomb Repressive Complex 2; D004722:Endoribonucleases; D010749:Phosphoprotein Phosphatases; D054645:Protein Phosphatase 1; C097081:PPP1R8 protein, human