Tension-sensitive Plk1 phosphorylation on BubR1 regulates the stability of kinetochore-microtubule interactions
Tension-sensitive Plk1 phosphorylation on BubR1 regulates the stability of kinetochore-microtubule interactions
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DOI：
10.1101/gad.436007
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发表时间：
2007-09-01
影响因子：
10.5
通讯作者：
Nigg, Erich A.
中科院分区：
文献类型：
--
作者：
Elowe, Sabine;Huemmer, Stefan;Nigg, Erich A.
纺锤体检查点成分BubR1的有丝分裂磷酸化在进化过程中高度保守。在此，我们证明BubR1在细胞周期蛋白依赖性激酶1（Cdk1）位点T620处被磷酸化，这在体外和体内都会触发Plk1的募集以及BubR1被Plk1磷酸化。磷酸化似乎并非纺锤体检查点功能所必需，但对于动粒 - 微管（KT - MT）相互作用的稳定性、有丝分裂的适时进展以及染色体在中期板上的排列非常重要。通过定量质谱分析，我们确定S676是BubR1上Plk1特异性的磷酸化位点。此外，利用一种磷酸化特异性抗体，我们表明该位点在前中期被磷酸化，但在姐妹染色单体之间建立张力时在中期去磷酸化。这些发现描述了人类BubR1第一个在体内被验证的磷酸化位点，确定Plk1是导致有丝分裂中BubR1特征性迁移的激酶，并将一种动粒特异性功能归因于BubR1的高度磷酸化形式在稳定动粒 - 微管相互作用中的作用。
Mitotic phosphorylation of the spindle checkpoint component BubR1 is highly conserved throughout evolution. Here, we demonstrate that BubR1 is phosphorylated on the Cdk1 site T620, which triggers the recruitment of Plk1 and phosphorylation of BubR1 by Plk1 both in vitro and in vivo. Phosphorylation does not appear to be required for spindle checkpoint function but instead is important for the stability of kinetochore-microtubule (KT-MT) interactions, timely mitotic progression, and chromosome alignment onto the metaphase plate. By quantitative mass spectrometry, we identify S676 as a Plk1-specific phosphorylation site on BubR1. Furthermore, using a phospho-specific antibody, we show that this site is phosphorylated during prometaphase, but dephosphorylated at metaphase upon establishment of tension between sister chromatids. These findings describe the first in vivo verified phosphorylation site for human BubR1, identify Plk1 as the kinase responsible for causing the characteristic mitotic BubR1 upshift, and attribute a KT-specific function to the hyperphosphorylated form of BubR1 in the stabilization of KT-MT interactions.