Structural basis of the Scc2/cohesin interaction and its implication on cohesin loading

Scc2/粘连蛋白相互作用的结构基础及其对粘连蛋白负载的影响

• 批准号: BB/S002537/1
• 负责人: Bin Hu
• 金额: $ 57.19万
• 依托单位: University of Sheffield
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2019
• 资助国家: 英国
• 起止时间: 2019 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FS002537%2F1
• 关键词: Structural; basis; Scc2; cohesin; interaction

The biological features of all organisms (from bacteria to humans) are mainly decided by genetic information inherited from their parents. A large amount of genetic information is carried by a macromolecule called DNA, which is stored in each cell. When cells grow and divide, DNA is accurately duplicated into 'sisters' and equally transmitted to the two new-born daughter cells. Mistakes in this process can lead to catastrophic consequences, altering the fate of cells. This can cause cell death or diseases such as cancer and developmental disorders. To ensure the precise sharing out of the duplicated genetic information, sister DNAs produced after DNA replication are held together until they are ready to move to opposites poles of the cell, just before the cell divides. This phenomenon is called sister chromatid cohesion.Sister chromatid cohesion is mediated by a special machine called cohesin, which consists of three protein subunits. Cohesin also plays important roles in processes apart from sister chromatid cohesion, such as regulation of which genes are used, and repair of damaged DNA. Although it performs a variety of tasks with DNA, cohesin appears to have a very simple mode to interact with DNA. The three subunits interconnect each other to form a huge protein ring structure, and the ring can open and close, allowing the DNA fiber to enter or exit the ring. Precise regulation of cohesin's association and dissociation with DNA is fundamental for its actions. Defects in this regulation compromise cohesin's function, which in humans would lead to cancer and inherited developmental disorders (such as Cornelia de Lange CdLS and Roberts syndromes).Cohesin cannot directly bind DNA in vivo and its DNA association requires another protein complex called Scc2/4. Interestingly, more than half of reported CdLS cases are due to defective Scc2. Although cohesin has been studied over twenty years, our knowledge of molecular details in its Scc2-dependent loading reaction has progressed very little. We know a key event during this loading reaction is the assembly of Scc2/cohesin pre-loading complex. Therefore, revealing the structure of this complex will greatly improve our understanding of how Scc2 recruits cohesin to DNA, which is the ultimate goal of this study.The architecture of cohesin complex has been established and a pseudo-atomic structure of the Scc2/4 complex was published recently. The question is how to join these two structures together to get a whole picture of the pre-loading complex. The key to this is to precisely map Scc2/cohesin interfaces or interaction sites. Our preliminary experiments discovered several regions of cohesin which are the Scc2-interacting sites. In this study, we will determine these interfaces using comprehensive genetic, biochemical, and biophysical approaches. All these results allow us to create a structural model of the Scc2/cohesin pre-loading complex, which will cast fresh light on the molecular mechanism of the cohesin loading. Insight into this fundamental process will help us understand how DNA segregation sometimes fails in cell division, as in cancer cells, or how our developmental programme goes wrong, which gives rise to cohesin-related diseases.

所有生物体（从细菌到人类）的生物学特征主要取决于从父母那里继承的遗传信息。大量的遗传信息由一种叫做DNA的大分子携带，储存在每个细胞中。当细胞生长和分裂时，DNA被准确地复制成“姐妹篇”，并平等地传递给两个新生的子细胞。这个过程中的错误可能导致灾难性的后果，改变细胞的命运。这可能导致细胞死亡或疾病，如癌症和发育障碍。为了确保复制的遗传信息的精确共享，DNA复制后产生的姐妹DNA被保持在一起，直到它们准备好移动到细胞的两极，就在细胞分裂之前。这种现象被称为姐妹染色单体凝聚。姐妹染色单体凝聚是由一种称为凝聚素的特殊机器介导的，它由三个蛋白质亚基组成。除了姐妹染色单体凝聚外，凝聚素还在其他过程中发挥重要作用，例如调节哪些基因被使用，以及修复受损的DNA。虽然它与DNA执行各种任务，但粘着蛋白似乎具有与DNA相互作用的非常简单的模式。这三个亚基相互连接，形成一个巨大的蛋白质环结构，环可以打开和关闭，允许DNA纤维进入或退出环。精确调控cohesin与DNA的结合和解离是cohesin发挥作用的基础。这种调节的缺陷损害了粘着蛋白的功能，这在人类中会导致癌症和遗传性发育障碍（如科尔内利亚德兰格CdLS和罗伯茨综合征）。粘着蛋白不能在体内直接结合DNA，其DNA结合需要另一种称为Scc 2/4的蛋白质复合物。有趣的是，报告的CdLS病例中有一半以上是由于Scc 2缺陷所致。虽然cohesin已经研究了二十多年，我们的知识的分子细节，在其Scc 2依赖加载反应进展甚微。我们知道在这个加载反应中的一个关键事件是Scc 2/cohesin预加载复合物的组装。因此，揭示Scc 2/4复合物的结构将极大地提高我们对Scc 2如何将cohesin招募到DNA中的理解，这也是本研究的最终目标。问题是如何将这两个结构连接在一起，以获得预加载复合体的全貌。其关键是精确地映射Scc 2/cohesin界面或相互作用位点。我们的初步实验发现了几个区域的cohesin这是Scc 2相互作用的网站。在这项研究中，我们将确定这些接口综合遗传，生物化学和生物物理方法。所有这些结果使我们能够创建Scc 2/cohesin预加载复合物的结构模型，这将为cohesin加载的分子机制提供新的思路。深入了解这一基本过程将有助于我们理解DNA分离有时在细胞分裂中是如何失败的，比如在癌细胞中，或者我们的发育程序是如何出错的，这会导致与粘着蛋白相关的疾病。

项目成果

Folding of cohesin's coiled coil is important for Scc2/4-induced association with chromosomes.

• DOI: 10.7554/elife.67268
• 发表时间: 2021-07-14
• 期刊: eLife
• 影响因子: 7.7
• 作者: Petela NJ;Gonzalez Llamazares A;Dixon S;Hu B;Lee BG;Metson J;Seo H;Ferrer-Harding A;Voulgaris M;Gligoris T;Collier J;Oh BH;Löwe J;Nasmyth KA
• 通讯作者: Nasmyth KA

Conformational dynamics of cohesin/Scc2 loading complex are regulated by Smc3 acetylation and ATP binding.

• DOI: 10.1038/s41467-023-41596-w
• 发表时间: 2023-09-22
• 期刊: NATURE COMMUNICATIONS
• 影响因子: 16.6
• 作者: Kaushik, Aditi;Than, Thane;Petela, Naomi J.;Voulgaris, Menelaos;Percival, Charlotte;Daniels, Peter;Rafferty, John B.;Nasmyth, Kim A.;Hu, Bin
• 通讯作者: Hu, Bin