Structure of the cohesin loader Scc2.
Structure of the cohesin loader Scc2.
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DOI：
10.1038/ncomms13952
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发表时间：
2017-01-06
影响因子：
16.6
通讯作者：
Singleton MR
中科院分区：
文献类型：
--
作者：
Chao WC;Murayama Y;Muñoz S;Jones AW;Wade BO;Purkiss AG;Hu XW;Borg A;Snijders AP;Uhlmann F;Singleton MR
粘连蛋白的功能对于基因组完整性、染色体组织和转录调控至关重要，它可以防止姐妹染色单体过早分离和 DNA 环的形成。染色质上粘连蛋白的负载取决于 Scc2-Scc4 复合物；然而，人们对它如何刺激内聚力加载活动知之甚少。在这里，我们确定了 Scc2 负责催化粘连蛋白加载的大“钩子”结构。我们确定了对体内黏连蛋白加载至关重要的关键 Scc2 表面。借助先前确定的结构和同源建模，我们推导出全长 Scc2-Scc4 复合物的伪原子结构。最后，使用重组纯化的 Scc2-Scc4 和粘连蛋白，我们进行了交联质谱和相互作用测定，表明 Scc2-Scc4 使用其模块化结构与粘连蛋白进行多次接触。粘连蛋白复合物通过确保有丝分裂和减数分裂期间正确的姐妹染色单体分离来维持基因组完整性。在这里，Chao 等人。提出了全长 Scc2-Scc4 粘连蛋白装载复合物的伪原子模型，并揭示了对于粘连蛋白装载至关重要的关键 Scc2 表面。
The functions of cohesin are central to genome integrity, chromosome organization and transcription regulation through its prevention of premature sister-chromatid separation and the formation of DNA loops. The loading of cohesin onto chromatin depends on the Scc2–Scc4 complex; however, little is known about how it stimulates the cohesion-loading activity. Here we determine the large ‘hook' structure of Scc2 responsible for catalysing cohesin loading. We identify key Scc2 surfaces that are crucial for cohesin loading in vivo. With the aid of previously determined structures and homology modelling, we derive a pseudo-atomic structure of the full-length Scc2–Scc4 complex. Finally, using recombinantly purified Scc2–Scc4 and cohesin, we performed crosslinking mass spectrometry and interaction assays that suggest Scc2–Scc4 uses its modular structure to make multiple contacts with cohesin. The cohesin complex maintains genome integrity by ensuring correct sister-chromatid segregation during mitosis and meiosis. Here, Chao et al. present a pseudo-atomic model of the full-length Scc2–Scc4 cohesin loader complex and reveal key Scc2 surfaces crucial for cohesin loading.