Protein Phosphorylation Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK.
Protein Purification Facility, Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK.
Nat Commun. 2016 Dec 22;7:13853. doi: 10.1038/ncomms13853.
The 'NoCut', or Aurora B abscission checkpoint can be activated if DNA is retained in the cleavage furrow after completion of anaphase. Checkpoint failure leads to incomplete abscission and a binucleate outcome. These phenotypes are also observed after loss of PKCɛ in transformed cell models. Here we show that PKCɛ directly modulates the Aurora B-dependent abscission checkpoint by phosphorylating Aurora B at S227. This phosphorylation invokes a switch in Aurora B specificity, with increased phosphorylation of a subset of target substrates, including the CPC subunit Borealin. This switch is essential for abscission checkpoint exit. Preventing the phosphorylation of Borealin leads to abscission failure, as does expression of a non-phosphorylatable Aurora B S227A mutant. Further, depletion of the ESCRT-III component and Aurora B substrate CHMP4C enables abscission, bypassing the PKCɛ-Aurora B exit pathway. Thus, we demonstrate that PKCɛ signals through Aurora B to exit the abscission checkpoint and complete cell division.
“无切割”（NoCut），或 Aurora B 分离检查点，如果有丝分裂后期完成后 DNA 仍滞留在分裂沟中，就会被激活。检查点失活会导致不完全分离和双核结果。在转化细胞模型中丢失 PKCɛ 后，也观察到这些表型。在这里，我们表明 PKCɛ 通过磷酸化 Aurora B 上的 S227 直接调节 Aurora B 依赖性分离检查点。这种磷酸化引发了 Aurora B 特异性的转变，增加了一组靶底物的磷酸化，包括 CPC 亚基 Borealin。这种转变对于分离检查点退出至关重要。阻止 Borealin 的磷酸化会导致分离失败，表达非磷酸化的 Aurora B S227A 突变体也是如此。此外，耗尽 ESCRT-III 成分和 Aurora B 底物 CHMP4C 可使分离发生，绕过 PKCɛ-Aurora B 退出途径。因此，我们证明 PKCɛ 通过 Aurora B 发出信号以退出分离检查点并完成细胞分裂。
