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Mol Cell. 2018 May 3;70(3):422-434.e6. doi: 10.1016/j.molcel.2018.03.020. Epub 2018 Apr 19.

Allosteric Activation Dictates PRC2 Activity Independent of Its Recruitment to Chromatin.

Author information

1
Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA.
2
Department of Chemistry, New York University, New York, NY 10003, USA.
3
Shared Bioinformatics Core, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA.
4
Department of Biochemistry and Molecular Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
5
Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA. Electronic address: danny.reinberg@nyumc.org.

Abstract

PRC2 is a therapeutic target for several types of cancers currently undergoing clinical trials. Its activity is regulated by a positive feedback loop whereby its terminal enzymatic product, H3K27me3, is specifically recognized and bound by an aromatic cage present in its EED subunit. The ensuing allosteric activation of the complex stimulates H3K27me3 deposition on chromatin. Here we report a stepwise feedback mechanism entailing key residues within distinctive interfacing motifs of EZH2 or EED that are found to be mutated in cancers and/or Weaver syndrome. PRC2 harboring these EZH2 or EED mutants manifested little activity in vivo but, unexpectedly, exhibited similar chromatin association as wild-type PRC2, indicating an uncoupling of PRC2 activity and recruitment. With genetic and chemical tools, we demonstrated that targeting allosteric activation overrode the gain-of-function effect of EZH2Y646X oncogenic mutations. These results revealed critical implications for the regulation and biology of PRC2 and a vulnerability in tackling PRC2-addicted cancers.

KEYWORDS:

EZH2; H3K27 methylation; PRC2; allosteric activation; alpha-helical mimetics

PMID:
29681499
PMCID:
PMC5935545
DOI:
10.1016/j.molcel.2018.03.020
[Indexed for MEDLINE]
Free PMC Article

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