The acetyltransferase Eco1 elicits cohesin dimerization during S phase
The acetyltransferase Eco1 elicits cohesin dimerization during S phase
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乙酰转移酶 Eco1 在 S 期引发粘连蛋白二聚化
DOI：
10.1074/jbc.ra120.013102
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发表时间：
2020-05-29
影响因子：
4.8
通讯作者：
Lou，Huiqiang
中科院分区：
文献类型：
--
作者：
Shi，Di;Zhao，Shuaijun;Lou，Huiqiang
内聚蛋白是一种DNA相关蛋白复合物，形成一个三环，控制姐妹染色单体内聚、染色体分离和组织、DNA复制和基因表达。姐妹染色单体内聚是由蛋白乙酰转移酶Eco1建立的，该酶使内聚蛋白亚基Smc3上的两个保守赖氨酸残基乙酰化，从而确保酵母（Saccharomyces cerevisiae）和其他真核生物中的染色单体正确分离。然而，eco1催化的内聚蛋白乙酰化的后果是未知的，染色单体内聚状态的确切性质仍然存在争议。本研究表明，在酵母和人类细胞中，内聚蛋白亚基Scc1/Rad21和Scc3的自相互作用以DNA复制偶联的方式发生。使用基于ms的交联和体内二硫交联的纯化黏结蛋白分析，我们表明黏结蛋白亚群可能以二聚体的形式存在。重要的是，在温度敏感和生长素诱导的降解介导的Eco1缺失后，内聚蛋白-内聚蛋白相互作用显著受损，而删除去乙酰化酶Hos1或Eco1拮抗剂Wpl1/Rad61可使内聚蛋白二聚体水平提高约20%。这些结果表明，黏结蛋白在S期二聚，在有丝分裂中单体化，这一过程在姐妹染色单体黏结-溶解循环中由Eco1、Wpl1和Hos1控制。这些发现表明黏结蛋白二聚化受黏结循环的控制，并支持双环黏结蛋白模式在姐妹染色单体黏结中起作用的观点。
Cohesin is a DNA-associated protein complex that forms a tripartite ring controlling sister chromatid cohesion, chromosome segregation and organization, DNA replication, and gene expression. Sister chromatid cohesion is established by the protein acetyltransferase Eco1, which acetylates two conserved lysine residues on the cohesin subunit Smc3 and thereby ensures correct chromatid separation in yeast (Saccharomyces cerevisiae) and other eukaryotes. However, the consequence of Eco1-catalyzed cohesin acetylation is unknown, and the exact nature of the cohesive state of chromatids remains controversial. Here, we show that self-interactions of the cohesin subunits Scc1/Rad21 and Scc3 occur in a DNA replication–coupled manner in both yeast and human cells. Using cross-linking MS-based and in vivo disulfide cross-linking analyses of purified cohesin, we show that a subpopulation of cohesin may exist as dimers. Importantly, upon temperature-sensitive and auxin-induced degron-mediated Eco1 depletion, the cohesin-cohesin interactions became significantly compromised, whereas deleting either the deacetylase Hos1 or the Eco1 antagonist Wpl1/Rad61 increased cohesin dimer levels by ∼20%. These results indicate that cohesin dimerizes in the S phase and monomerizes in mitosis, processes that are controlled by Eco1, Wpl1, and Hos1 in the sister chromatid cohesion-dissolution cycle. These findings suggest that cohesin dimerization is controlled by the cohesion cycle and support the notion that a double-ring cohesin model operates in sister chromatid cohesion.