Deacetylation of the mitotic checkpoint protein BubR1 at lysine 250 by SIRT2 and subsequent effects on BubR1 degradation during the prometaphase/anaphase transition.
Deacetylation of the mitotic checkpoint protein BubR1 at lysine 250 by SIRT2 and subsequent effects on BubR1 degradation during the prometaphase/anaphase transition.
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DOI：
10.1016/j.bbrc.2014.09.128
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发表时间：
2014-10
影响因子：
3.1
通讯作者：
T. Suematsu;Yanze Li;H. Kojima;K. Nakajima;M. Oshimura;Toshiaki Inoue
中科院分区：
文献类型：
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作者：
T. Suematsu;Yanze Li;H. Kojima;K. Nakajima;M. Oshimura;Toshiaki Inoue
有丝分裂灾难是在有丝分裂期间和有丝分裂滑移到四倍体状态后发生的一种细胞死亡形式，在微管抑制剂杀死癌细胞的功效中起重要作用。在纺锤体组装检查点（SAC）的延长的有丝分裂停滞是有丝分裂灾难的众所周知的要求，因此，赋予对微管抑制剂的敏感性。我们以前报道过，SIRT 2，NAD+依赖性脱乙酰酶的sirtuin家族的成员，通过异常延长有丝分裂停滞，从而损害有丝分裂滑移后的细胞死亡途径，赋予微管抑制剂的抗性。因此，在限定的时间段之后关闭SAC激活是有效的滑移后死亡的附加要求。在这里，我们研究了SIRT 2是否使BubR 1去乙酰化，BubR 1是SAC的核心成分;在前中期，BubR 1在赖氨酸250（K250）处的乙酰化抑制了其APC/C依赖的蛋白水解，从而调节了后期进入的时间。我们发现SIRT 2在体外和体内都使BubR 1 K250脱乙酰基。我们还发现，SIRT 2敲除会导致分裂前期BubR 1乙酰化水平增加;然而，这种增加对于提高总BubR 1水平或延迟从分裂前期到分裂后期的转变并不显着。目前的研究表明，SIRT 2是一种BubR 1 K250的脱乙酰酶，尽管在SIRT 2敲除细胞中观察到的异常延长的SAC激活并不伴随着BubR 1水平的变化或从前中期到后期的延迟进展。
Mitotic catastrophe, a form of cell death that occurs during mitosis and after mitotic slippage to a tetraploid state, plays an important role in the efficacy of cancer cell killing by microtubule inhibitors. Prolonged mitotic arrest at the spindle assembly checkpoint (SAC) is a well-known requirement for mitotic catastrophe and, thus, for conferring sensitivity to microtubule inhibitors. We previously reported that downregulation of SIRT2, a member of the sirtuin family of NAD+-dependent deacetylases, confers resistance to microtubule inhibitors by abnormally prolonging mitotic arrest and thus compromising the cell death pathway after mitotic slippage. Thus, turning off SAC activation after a defined period is an additional requirement for efficient post-slippage death. Here, we investigated whether SIRT2 deacetylates BubR1, which is a core component of the SAC; acetylation of BubR1 at lysine 250 (K250) during prometaphase inhibits its APC/C-dependent proteolysis and thus regulates timing in anaphase entry. We showed that SIRT2 deacetylates BubR1 K250 both in vitro and in vivo. We also found that SIRT2 knockdown leads to increased levels of BubR1 acetylation at prometaphase; however, this increase is not substantial to elevate the levels of total BubR1 or delay the transition from prometaphase to anaphase. The present study shows that SIRT2 is a deacetylase for BubR1 K250, although the abnormally prolonged SAC activation observed in SIRT2 knockdown cells is not accompanied by a change in BubR1 levels or by delayed progression from prometaphase to anaphase.