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.

所有生物体（从细菌到人类）的生物学特征主要是由从父母遗传的遗传信息决定的。大量的遗传信息是由一种称为DNA的大分子携带的，它存储在每个细胞中。当细胞生长和分裂时，DNA 被准确地复制成“姐妹细胞”，并同等地传递给两个新生的子细胞。这个过程中的错误可能会导致灾难性的后果，改变细胞的命运。这可能导致细胞死亡或癌症和发育障碍等疾病。为了确保精确共享重复的遗传信息，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。这种现象称为姐妹染色单体内聚力。姐妹染色单体内聚力是由一种称为粘连蛋白的特殊机器介导的，该机器由三个蛋白质亚基组成。粘连蛋白还在姐妹染色单体粘连以外的过程中发挥着重要作用，例如调节使用哪些基因以及修复受损的 DNA。尽管粘连蛋白与 DNA 执行多种任务，但其与 DNA 相互作用的模式似乎非常简单。三个亚基相互连接，形成巨大的蛋白质环状结构，环可以打开和关闭，允许DNA纤维进入或离开环。粘连蛋白与 DNA 的结合和解离的精确调节是其作用的基础。这种调节的缺陷会损害粘连蛋白的功能，这在人类中会导致癌症和遗传性发育障碍（例如 Cornelia de Lange CdLS 和 Roberts 综合征）。粘连蛋白在体内不能直接结合 DNA，其 DNA 结合需要另一种称为 Scc2/4 的蛋白质复合物。有趣的是，超过一半的 CdLS 病例是由于 Scc2 缺陷所致。尽管粘连蛋白的研究已有二十多年，但我们对其依赖于 Scc2 的负载反应的分子细节的了解却进展甚微。我们知道加载反应过程中的一个关键事件是 Scc2/粘连蛋白预加载复合物的组装。因此，揭示该复合物的结构将极大地提高我们对Scc2如何将粘连蛋白招募到DNA上的理解，这也是本研究的最终目标。粘连蛋白复合物的结构已经建立，并建立了Scc2/4复合物的伪原子结构最近发布了。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。其关键是精确绘制 Scc2/cohesin 界面或相互作用位点。我们的初步实验发现了粘连蛋白的几个区域，它们是 Scc2 相互作用位点。在这项研究中，我们将使用综合遗传、生物化学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/粘连蛋白预加载复合物的结构模型，这将为粘连蛋白加载的分子机制提供新的线索。深入了解这一基本过程将有助于我们了解 DNA 分离有时如何在细胞分裂中失败（例如在癌细胞中），或者我们的发育程序如何出错，从而导致与粘连蛋白相关的疾病。

项目成果

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

Cohesin/Scc2 负载复合物的构象动力学受 Smc3 乙酰化和 ATP 结合调节

• DOI: http://dx.10.1101/2022.12.04.519023
• 发表时间: 2022
• 作者: Kaushik A

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

粘连蛋白卷曲螺旋的折叠对于 Scc2/4 诱导的染色体关联非常重要。

• DOI: http://dx.10.7554/elife.67268
• 发表时间: 2021
• 期刊: eLife
• 影响因子: 7.7
• 作者: Petela NJ

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

Cohesin/Scc2 负载复合物的构象动力学受 Smc3 乙酰化和 ATP 结合的调节。

• DOI: http://dx.10.1038/s41467-023-41596-w
• 发表时间: 2023
• 期刊: Nature communications
• 影响因子: 16.6
• 作者: Kaushik A