Phosphorylation of the cohesin subunit Scc1 by Polo/Cdc5 kinase regulates sister chromatid separation in yeast
Phosphorylation of the cohesin subunit Scc1 by Polo/Cdc5 kinase regulates sister chromatid separation in yeast
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DOI：
10.1016/s0092-8674(01)00362-2
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发表时间：
2001-05-18
期刊：
影响因子：
64.5
通讯作者：
Nasmyth, K
中科院分区：
文献类型：
--
作者：
Alexandru, G;Uhlmann, F;Nasmyth, K
在后期开始时，caspase相关蛋白酶（分离酶）通过分裂内聚蛋白亚基Scc1破坏姐妹染色单体之间的连接。在细胞周期的大部分时间里，分离酶通过与一种叫做安全蛋白的抑制蛋白结合而保持非活性。分离酶的激活需要securin的蛋白水解，这是由一种称为后期促进复合体的泛素蛋白连接酶介导的。细胞通过延迟安全蛋白泛素化来调节后期进入，直到所有染色体都附着在有丝分裂纺锤体上。虽然不再受这种有丝分裂监视机制的调节，但在缺乏安全蛋白的酵母突变体中，姐妹分离仍然受到细胞周期的严格调节。我们在这里表明，Polo/Cdc5激酶磷酸化了Scc1切割位点附近的丝氨酸残基，并强烈增强了它们的切割。分离酶识别位点的磷酸化可能是高度保守的，并且独立于securin调节姐妹染色单体的分离。
At the onset of anaphase, a caspase-related protease (separase) destroys the link between sister chromatids by cleaving the cohesin subunit Scc1. During most of the cell cycle, separase is kept inactive by binding to an inhibitory protein called securin. Separase activation requires proteolysis of securin, which is mediated by an ubiquitin protein ligase called the anaphase-promoting complex. Cells regulate anaphase entry by delaying securin ubiquitination until all chromosomes have attached to the mitotic spindle. Though no longer regulated by this mitotic surveillance mechanism, sister separation remains tightly cell cycle regulated in yeast mutants lacking securin. We show here that the Polo/Cdc5 kinase phosphorylates serine residues adjacent to Scc1 cleavage sites and strongly enhances their cleavage. Phosphorylation of separase recognition sites may be highly conserved and regulates sister chromatid separation independently of securin.