期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2018
卷号：115
期号：28
页码：7302-7307
DOI：10.1073/pnas.1801850115
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Protein O -glycosylation by attachment of β- N -acetylglucosamine (GlcNAc) to the Ser or Thr residue is a major posttranslational glycosylation event and is often associated with protein folding, stability, and activity. The methylation of histone H3 at Lys-27 catalyzed by the methyltransferase EZH2 was known to suppress gene expression and cancer development, and we previously reported that the O -GlcNAcylation of EZH2 at S76 stabilized EZH2 and facilitated the formation of H3K27me3 to inhibit tumor suppression. In this study, we employed a fluorescence-based method of sugar labeling combined with mass spectrometry to investigate EZH2 glycosylation and identified five O -GlcNAcylation sites. We also find that mutation of one or more of the O -GlcNAcylation sites S73A, S76A, S84A, and T313A in the N-terminal region decreases the stability of EZH2, but does not affect its association with the PRC2 components SUZ12 and EED. Mutation of the C-terminal O -GlcNAcylation site (S729A) in the catalytic domain of EZH2 abolishes the di- and trimethylation activities, but not the monomethylation of H3K27, nor the integrity of the PRC2/EZH2 core complex. Our results show the effect of individual O -GlcNAcylation sites on the function of EZH2 and suggest an alternative approach to tumor suppression through selective inhibition of EZH2 O -GlcNAcylation.
关键词：O -GlcNAcylation ; methyltransferase EZH2 ; H3K27me3 ; cancer
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