Spindle Assembly Checkpoint Silencing

主轴装配检查点消音

• 批准号: 10623841
• 负责人: Nicholas Gene Brown
• 金额: $ 45.41万
• 依托单位: UNIV OF NORTH CAROLINA CHAPEL HILL
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-08-01 至 2028-07-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10623841
• 关键词: ATP phosphohydrolase; Binding; Cell Cycle; Cell Cycle Checkpoint; Cell division; Cellular biology; Chromatin; Chromosome Segregation; Chromosomes; Complex; Coupling; Cryoelectron Microscopy; Cyclin B; Defect; Development; Disease; Ensure; Eukaryotic Cell; Event; G1 Phase; Gene Expression; Gene Proteins; Genetic Transcription; In Vitro; Malignant Neoplasms; Mitosis; Mitotic; Mitotic Checkpoint; Molecular Conformation; Molecular Machines; Nucleosomes; PTTG1 gene; Phosphotransferases; Photometry; Polyubiquitination; Post-Translational Protein Processing; Process; Proteins; Regulation; Research; Techniques; Time; Ubiquitination; anaphase-promoting complex; cardiogenesis; daughter cell; inhibitor; innovation; protein degradation; reconstitution; scaffold; tumor progression; ubiquitin ligase

PROJECT SUMMARY Eukaryotic cell cycle is tightly controlled by an intricate sequence of events where both gene expression and protein degradation are under intense regulation. When the cell cycle is dysregulated, uncontrolled division ensues–a hallmark of cancer. Therefore, cell cycle checkpoints, such as the spindle assembly checkpoint (SAC), ensure faithful chromosome segregation and produce healthy daughter cells. During an active checkpoint, transcription is reduced and the primary ubiquitin ligase of mitosis, the Anaphase-Promoting Complex/Cyclosome (APC/C), is inhibited by the 4-subunit Mitotic Checkpoint Complex (MCC). Once the chromosomes are ready and the checkpoint is satisfied, the APC/C is freed from MCC inhibition through conformational rearrangements that permit MCC ubiquitination. The APC/C targets several well-established cell cycle regulators (e.g., Cyclin B and Securin) and chromatin regulators, including the chromatin building blocks–nucleosomes, for destruction, coupling mitotic exit and transcription. The APC/C-dependent progression through mitosis is incredibly complicated as it requires the participation of dozens of proteins, including activators, inhibitors, kinases, AAA-ATPases, and substrates. How all this regulation is successfully integrated on a single APC/C scaffold is unclear but highly significant because it is at the intersection of both protein degradation and gene expression for G1 phase. By reconstituting these processes in vitro with innovative techniques, such as time-resolved cryo-EM and mass photometry, we can better understand how polyubiquitination occurs, how specific cell cycle effectors influence the conformational states of MCC-bound APC/C, and how the nucleosome is targeted by the APC/C. The information gained from these studies will lead to an unprecedented understanding of the SAC and coordinated gene expression, which is at the heart of development, cell biology, and countless disease processes, including cancer.

项目概要 真核细胞周期受到一系列复杂事件的严格控制，其中基因表达和 当细胞周期失调、分裂失控时，蛋白质降解受到强烈调节。 随之而来的是细胞周期检查点，例如纺锤体组装检查点。 (SAC)，确保染色体忠实分离并在活跃期间产生健康的子细胞。 检查点，转录减少，有丝分裂的主要泛素连接酶，后期促进 复合物/环体 (APC/C) 被 4 亚基有丝分裂检查点复合物 (MCC) 抑制。 染色体准备好并且检查点得到满足，APC/C 通过以下方式摆脱 MCC 抑制 APC/C 的构象重排允许 MCC 泛素化。 细胞周期调节因子（例如 Cyclin B 和 Securin）和染色质调节因子，包括染色质构建 阻断核小体，用于破坏、耦合有丝分裂退出和转录。 有丝分裂的进展极其复杂，因为它需要数十种蛋白质的参与， 包括激活剂、抑制剂、激酶、AAA-ATP酶和底物所有这些调节是如何成功的。 集成在单个 APC/C 支架上尚不清楚，但非常重要，因为它位于两者的交叉点 G1 期的蛋白质降解和基因表达 通过在体外重建这些过程。 创新技术，例如时间分辨冷冻电镜和质量光度测定，我们可以更好地了解如何 发生多泛素化，特定细胞周期效应如何影响 MCC 结合的构象状态 APC/C，以及 APC/C 如何靶向核小体 从这些研究中获得的信息将引导我们。 对 SAC 和协调基因表达有了前所未有的了解，这是 发育、细胞生物学和无数疾病过程，包括癌症。