Dynamic regulation of the PR-Set7 histone methyltransferase is required for normal cell cycle progression (original) (raw)

  1. Weiping Wang2,
  2. Xiangduo Kong3,
  3. Lauren M. Congdon1,
  4. Kyoko Yokomori3,
  5. Marc W. Kirschner2 and
  6. Judd C. Rice1,4
  7. 1Department of Biochemistry and Molecular Biology, University of Southern California Keck School of Medicine, Los Angeles, California 90033, USA;
  8. 2Department of Systems Biology, Harvard Medical School, Boston, Massachusetts 02115, USA;
  9. 3Department of Biological Chemistry, School of Medicine, University of California at Irvine, Irvine, California 92697, USA

Abstract

Although the PR-Set7/Set8/KMT5a histone H4 Lys 20 monomethyltransferase (H4K20me1) plays an essential role in mammalian cell cycle progression, especially during G2/M, it remained unknown how PR-Set7 itself was regulated. In this study, we discovered the mechanisms that govern the dynamic regulation of PR-Set7 during mitosis, and that perturbation of these pathways results in defective mitotic progression. First, we found that PR-Set7 is phosphorylated at Ser 29 (S29) specifically by the cyclin-dependent kinase 1 (cdk1)/cyclinB complex, primarily from prophase through early anaphase, subsequent to global accumulation of H4K20me1. While S29 phosphorylation did not affect PR-Set7 methyltransferase activity, this event resulted in the removal of PR-Set7 from mitotic chromosomes. S29 phosphorylation also functions to stabilize PR-Set7 by directly inhibiting its interaction with the anaphase-promoting complex (APC), an E3 ubiquitin ligase. The dephosphorylation of S29 during late mitosis by the Cdc14 phosphatases was required for APCcdh1-mediated ubiquitination of PR-Set7 and subsequent proteolysis. This event is important for proper mitotic progression, as constitutive phosphorylation of PR-Set7 resulted in a substantial delay between metaphase and anaphase. Collectively, we elucidated the molecular mechanisms that control PR-Set7 protein levels during mitosis, and demonstrated that its orchestrated regulation is important for normal mitotic progression.

Footnotes