An Integrative Proteomic Approach Identifies Novel Cellular SMYD2 Substrates

Author

Hazem Ahmed^†, Shili Duan^‡, Cheryl H. Arrowsmith^†‡, Dalia Barsyte-Lovejoy^† and Matthieu Schapira^*†§

*E-mail: matthieu.schapira@utoronto.ca.

†Structural Genomics Consortium, University of Toronto, 101 College Street, MaRS Centre, South Tower, Toronto, Ontario M5G 1L7, Canada

‡Princess Margaret Cancer Centre and Department of Medical Biophysics, University of Toronto, Toronto, Ontario M5S 1A8, Canada

§Department of Pharmacology and Toxicology, University of Toronto; 1 King’s College Circle, Toronto, Ontario M5S 1A8, Canada

Journal of Proteome Research

Vol. 15: Issue. 6: Pages. 2052-2059

Publication Date (Web): May 10, 2016

DOI: 10.1021/acs.jproteome.6b00220

Protein methylation is a post-translational modification with important roles in transcriptional regulation and other biological processes, but the enzyme–substrate relationship between the 68 known human protein methyltransferases and the thousands of reported methylation sites is poorly understood. Here, we propose a bioinformatic approach that integrates structural, biochemical, cellular, and proteomic data to identify novel cellular substrates of the lysine methyltransferase SMYD2. Of the 14 novel putative SMYD2 substrates identified by our approach, six were confirmed in cells by immunoprecipitation: MAPT, CCAR2, EEF2, NCOA3, STUB1, and UTP14A. Treatment with the selective SMYD2 inhibitor BAY-598 abrogated the methylation signal, indicating that methylation of these novel substrates was dependent on the catalytic activity of the enzyme. We believe that our integrative approach can be applied to other protein lysine methyltransferases, and help understand how lysine methylation participates in wider signaling processes.

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http://pubs.acs.org/doi/abs/10.1021/acs.jproteome.6b00205#/doi/full/10.1021/acs.jproteome.6b00208