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/S002537/2
• 负责人: Bin Hu
• 金额: $ 43.71万
• 依托单位: University of Aberdeen
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2020
• 资助国家: 英国
• 起止时间: 2020 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FS002537%2F2
• 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（从细菌到人类）的生物学特征主要由父母继承的遗传信息决定。大量遗传信息由称为DNA的大分子携带，该大分子存储在每个细胞中。当细胞生长和分裂时，将DNA准确地复制到“姐妹”中，并同样传播到两个新出生的子女细胞。在此过程中的错误会导致灾难性后果，从而改变细胞的命运。这会导致细胞死亡或癌症和发育障碍等疾病。为了确保重复的遗传信息的精确共享，将DNA复制后产生的姐妹DNA固定在一起，直到他们准备好移动到细胞分裂之前的细胞对立杆。这种现象称为姐妹染色单体内聚力。西斯特染色单体的内聚会是由一种称为粘蛋白的特殊机器介导的，该机器由三个蛋白质亚基组成。除了姐妹染色单体内聚会（例如使用哪些基因的调节）以及受损的DNA的修复，粘着蛋白在过程中还起着重要作用。尽管它执行了多种DNA任务，但粘蛋白似乎具有与DNA相互作用的非常简单的模式。这三个亚基相互连接以形成巨大的蛋白环结构，环可以打开和关闭，使DNA纤维进入或退出环。粘蛋白的关联和与DNA解离的精确调节对于其作用是基础。该调节中的缺陷损害了粘素的功能，在人类中，这将导致癌症和遗传性发育障碍（例如Cornelia de Lange CDLS和Roberts综合征）。Cohesin不能直接在体内结合DNA及其DNA缔合需要另一种称为SCC2/4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SCC2缺陷。尽管二十年来已经研究了粘着素，但我们对SCC2依赖性负载反应中分子细节的了解却很少。我们知道在此加载反应期间的关键事件是SCC2/粘蛋白预载复合物的组装。因此，揭示该复合物的结构将大大提高我们对SCC2如何募集凝聚蛋白到DNA的理解，这是这项研究的最终目标。已建立了粘蛋白复合物的结构，并最近发表了SCC2/4复合体的伪原子结构。问题是如何将这两种结构结合在一起，以获取预加载综合体的整体图片。这样做的关键是精确映射SCC2/粘蛋白接口或交互位点。我们的初步实验发现了几个粘蛋白的区域，即SCC2相互作用位点。在这项研究中，我们将使用全面的遗传，生化和生物物理方法来确定这些界面。所有这些结果使我们能够创建SCC2/粘蛋白预载复合物的结构模型，该模型将对粘蛋白负荷的分子机理呈现新鲜的启示。洞悉这一基本过程将有助于我们了解DNA分离有时在细胞分裂中如何失败，例如癌细胞，或者我们的发育计划如何出错，这会导致与粘蛋白相关的疾病。

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

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

• DOI: 10.1101/2022.12.04.519023
• 发表时间: 2022-12-04
• 期刊: bioRxiv
• 作者: Kaushik, Aditi;Than, Thane;Hu, Bin
• 通讯作者: Hu, Bin