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J Biol Chem. 2018 Aug 17;293(33):12770-12780. doi: 10.1074/jbc.RA118.002890. Epub 2018 Jun 29.

Identification of Rpl29 as a major substrate of the lysine methyltransferase Set7/9.

Author information

1
From the Department of Epigenetics and Molecular Carcinogenesis, and.
2
the Center for Cancer Epigenetics, The University of Texas MD Anderson Cancer Center, Smithville, Texas 78957.
3
the Program in Genetics and Epigenetics, The University of Texas MD Anderson Cancer Center UT Health Graduate School of Biomedical Sciences, Houston, Texas 77030.
4
Cell Signaling Technology Inc., Danvers, Massachusetts 01923, and.
5
the Structural Genomics Consortium, and.
6
the Princess Margaret Cancer Centre and Department of Medical Biophysics, University of Toronto, Toronto, Ontario M5G 1L7, Canada.
7
From the Department of Epigenetics and Molecular Carcinogenesis, and tchen2@mdanderson.org.

Abstract

Set7/9 (also known as Set7, Set9, Setd7, and Kmt7) is a lysine methyltransferase that catalyzes the methylation of multiple substrates, including histone H3 and non-histone proteins. Although not essential for normal development and physiology, Set7/9-mediated methylation events play important roles in regulating cellular pathways involved in various human diseases, making Set7/9 a promising therapeutic target. Multiple Set7/9 inhibitors have been developed, which exhibit varying degrees of potency and selectivity in vitro However, validation of these compounds in vivo has been hampered by the lack of a reliable cellular biomarker for Set7/9 activity. Here, we report the identification of Rpl29, a ribosomal protein abundantly expressed in all cell types, as a major substrate of Set7/9. We show that Rpl29 lysine 5 (Rpl29K5) is methylated exclusively by Set7/9 and can be demethylated by Lsd1 (also known as Kdm1a). Rpl29 is not a core component of the ribosome translational machinery and plays a regulatory role in translation efficiency. Our results indicate that Rpl29 methylation has no effect on global protein synthesis but affects Rpl29 subcellular localization. Using an Rpl29 methylation-specific antibody, we demonstrate that Rpl29K5 methylation is present ubiquitously and validate that (R)-PFI-2, a Set7/9 inhibitor, efficiently reduces Rpl29K5 methylation in cell lines. Thus, Rpl29 methylation can serve as a specific cellular biomarker for measuring Set7/9 activity.

KEYWORDS:

Lsd1; Rpl29; Set7/9; biomarker; epigenetics; histone methylation; post-translational modification (PTM); ribosome function

PMID:
29959229
PMCID:
PMC6102145
[Available on 2019-08-17]
DOI:
10.1074/jbc.RA118.002890
[Indexed for MEDLINE]

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