Aurora B-dependent Regulation of Class IIa Histone Deacetylases by Mitotic Nuclear Localization Signal Phosphorylation
Class IIa histone deacetylases (HDACs 4/5/7/9) are transcriptional regulators with critical roles in cardiac disease, cancer, and viral infection. HDAC inhibitors are promising anti-cancer agents, and while they are known to disrupt mitotic progression, the underlying mechanisms of mitotic regulation by HDACs are not fully understood. Here we provide the first identification of histone deacetylases as substrates of Aurora B kinase (AurB). Our study identifies class IIa HDACs as a novel family of AurB targets and provides the first evidence that HDACs are temporally and spatially regulated by phosphorylation during the cell cycle. We define the precise sites of AurB-mediated phosphorylation as a conserved serine within the nuclear localization signals of HDAC4, HDAC5, and HDAC9 at Ser265, Ser278, and Ser242, respectively. We establish that AurB interacts with these HDACs in vivo, and that this association increases upon disruption of 14-3-3 binding. We observe co-localization of endogenous, phosphorylated HDACs with AurB at the mitotic midzone in late anaphase and the midbody during cytokinesis, complemented by a reduction in HDAC interactions with components of the nuclear co-repressor (NCoR) complex. We propose that AurB-dependent phosphorylation of HDACs induces sequestration within a phosphorylation gradient at the midzone, maintaining separation from re-forming nuclei and contributing to transcriptional control.
Available from: Jesper V Olsen
- "These are Aurora kinase B (Aurora B), Dual specificity protein kinase CLK3 and cGMP-dependent protein kinase 1 (PKG1). Recently, Aurora B was shown to phosphorylate certain histone deacetylases (HDACs) with critical roles in cardiac disease and thereby likely regulate their localization . PKG1 is involved in vascular smooth muscle relaxation, where it influences actin binding by the phosphorylation of proteins important for cytoskeletal reorganisation  which fits well with regulation by Ang II. "
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