Ubiquitination of Lysine 867 of the Human SETDB1 Protein Upregulates Its Histone H3 Lysine 9 (H3K9) Methyltransferase Activity

PLoS One. 2016 Oct 31;11(10):e0165766. doi: 10.1371/journal.pone.0165766. eCollection 2016.

Abstract

Posttranslational modifications (PTMs) of proteins play a crucial role in regulating protein-protein interactions, enzyme activity, subcellular localization, and stability of the protein. SET domain, bifurcated 1 (SETDB1) is a histone methyltransferase that regulates the methylation of histone H3 on lysine 9 (H3K9), gene silencing, and transcriptional repression. The C-terminal region of SETDB1 is a key site for PTMs, and is essential for its enzyme activity in mammalian and insect cells. In this study, we aimed to evaluate more precisely the effect of PTMs on the H3K9 methyltransferase activity of SETDB1. Using mass spectrometry analysis, we show that the C-terminal region of human SETDB1 purified from insect cells is ubiquitinated. We also demonstrate that the ubiquitination of lysine 867 of the human SETDB1 is necessary for full H3K9 methyltransferase activity in mammalian cells. Finally, we show that SETDB1 ubiquitination regulates the expression of its target gene, serpin peptidase inhibitor, clade E, member 1 (SERPINE1) by methylating H3K9. These results suggest that the ubiquitination of SETDB1 at lysine 867 controls the expression of its target gene by activating its H3K9 methyltransferase activity.

MeSH terms

  • Animals
  • Cell Line
  • Enzyme Activation
  • Gene Expression Regulation
  • Histone Methyltransferases
  • Histone-Lysine N-Methyltransferase / metabolism*
  • Histones / metabolism*
  • Humans
  • Lysine / metabolism*
  • Models, Biological
  • Protein Binding
  • Protein Interaction Domains and Motifs
  • Protein Methyltransferases / chemistry
  • Protein Methyltransferases / metabolism*
  • Ubiquitination

Substances

  • Histones
  • Histone Methyltransferases
  • Protein Methyltransferases
  • Histone-Lysine N-Methyltransferase
  • SETDB1 protein, human
  • Lysine

Grants and funding

This work was supported by JSPS KAKENHI Grant No. 25860253, 15H02896, 25670026 and 15H04644 (http://www.jsps.go.jp/english/index.html). The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.