Regulation of the Anaphase-Promoting Complex by the Spindle Checkpoint

纺锤体检查点对后期促进复合体的调节

基本信息

批准号：
7617863
负责人：
HONGTAO YU
金额：
$ 30.49万
依托单位：
UT SOUTHWESTERN MEDICAL CENTER
依托单位国家：
美国
项目类别：
财政年份：
2001
资助国家：
美国
起止时间：
2001-05-01 至 2011-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7617863
关键词：
Adopted Anaphase Antibodies Antimitotic Agents Antineoplastic Agents Benomyl Binding Biological Assay Boxing C-terminal Cell Cycle Cell Cycle Proteins Cells Centromere Chromosomes Cleaved cell Collection Complex Defect Drops Elements Goals Hela Cells Human In Vitro Interphase Kinetochores Lead Length Light MG132 Malignant Neoplasms Mammalian Cell Masks Mediating Metaphase Mitosis Mitotic Mitotic Checkpoint Mitotic spindle Modeling Molecular Molecular Conformation Mutate N-terminal Nocodazole Orthologous Gene Paclitaxel Pathway interactions Phosphorylation Phosphotransferases Proteasome Inhibitor Protein Deficiency Proteins Regulation Research Personnel Role Saccharomycetales Signal Transduction Sister Chromatid System Testing Ubiquitin Ubiquitination Xenopus anaphase-promoting complex base cancer cell cohesin egg human PTTG1 protein in vivo inhibitor/antagonist insight killings multicatalytic endopeptidase complex mutant premature prevent programs protein complex protein degradation reconstitution research study response separase ubiquitin ligase

项目摘要

DESCRIPTION (provided by applicant): The orderly progression through the cell division cycle requires periodic degradation of key cell cycle regulatory proteins by the ubiquitin-proteasome system. The anaphase-promoting complex or cyclosome (APC/C) is a large multi-subunit ubiquitin ligase that controls several cell cycle transitions, including the metaphase-anaphase transition. After all sister chromatids have achieved bipolar attachment to the mitotic spindle, APC/C in conjunction with its activator Cdc20 ubiquitinates securin, an inhibitor of separase. Degradation of securin activates separase, which then cleaves a subunit of cohesin and triggers sister- chromatid separation and the onset of anaphase. The activity of APC/C-Cdc20 is tightly controlled by multiple mechanisms to prevent premature sister-chromatid separation. The spindle checkpoint is one such APC/C-regulatory mechanism. Our long-term goal is to understand how the spindle checkpoint inhibits the activity of APC/C-Cdc20 and delays the onset of anaphase in response to a single unattached kinetochore within a mitotic cell. This proposal focuses on the mechanism of assembly and disassembly of the mitotic checkpoint complex (MCC), an important checkpoint inhibitor of APC/C. MCC contains BubR1, Bub3, Cdc20, and Mad2. BubR1 and Bub3 bind to each other constitutively throughout the cell cycle whereas the BubR1-Cdc20 and Mad2-Cdc20 interactions are enhanced during mitosis. The specific aims of this proposal are: (1) to determine the role of Mad1 -assisted conformational change of Mad2 in MCC assembly; (2) to determine the role of phosphorylation of Cdc20 by Bub1 in MCC assembly; and (3) to determine the role of Cdc20 autoubiquitination and degradation in MCC disassembly. Malfunction of the spindle checkpoint has been implicated in human cancers. The antimitotic class of anti-cancer drugs, such as Taxol, kills cancer cells by exploiting defects in this pathway. Experiments in this proposal will shed light on the molecular basis of the spindle checkpoint, which might eventually lead to new strategies to treat human cancers.

描述（由申请人提供）：细胞分裂周期的有序进展需要泛素-蛋白酶体系统定期降解关键细胞周期调节蛋白。后期促进复合物或环体 (APC/C) 是一种大型多亚基泛素连接酶，控制多个细胞周期转变，包括中期 - 后期转变。所有姐妹染色单体都实现了与有丝分裂纺锤体的双极附着后，APC/C 与其激活剂 Cdc20 一起泛素化 securin（一种分离酶抑制剂）。 securin 的降解会激活分离酶，然后分离酶裂解粘连蛋白的亚基并引发姐妹染色单体分离和后期的开始。 APC/C-Cdc20 的活性受到多种机制的严格控制，以防止姐妹染色单体过早分离。主轴检查点就是这样一种 APC/C 调节机制。我们的长期目标是了解纺锤体检查点如何抑制 APC/C-Cdc20 的活性并延迟后期的开始，以响应有丝分裂细胞内的单个未附着的动粒。该提案重点研究有丝分裂检查点复合体（MCC）的组装和分解机制，MCC是APC/C的重要检查点抑制剂。 MCC 包含 BubR1、Bub3、Cdc20 和 Mad2。 BubR1 和 Bub3 在整个细胞周期中持续相互结合，而 BubR1-Cdc20 和 Mad2-Cdc20 相互作用在有丝分裂过程中增强。该提案的具体目的是：（1）确定Mad1辅助Mad2构象变化在MCC组装中的作用； (2)确定Bub1磷酸化Cdc20在MCC组装中的作用； (3) 确定 Cdc20 自动泛素化和降解在 MCC 拆卸中的作用。纺锤体检查点的故障与人类癌症有关。抗有丝分裂类抗癌药物，例如紫杉醇，通过利用该途径中的缺陷来杀死癌细胞。该提案中的实验将揭示纺锤体检查点的分子基础，这可能最终导致治疗人类癌症的新策略。