The signal cascade of the spindle checkpoint

主轴检查点信号级联

• 批准号: 15370085
• 负责人: MATSUMOTO Tomohiro
• 金额: $ 9.66万
• 依托单位: Kyoto University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2003
• 资助国家: 日本
• 起止时间: 2003 至 2005
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-15370085/
• 关键词: mitosis; spindle checkpoint; Mad2; p31comet; DNCI; 細胞周期; 染色体安定性; 動原体; 紡錘糸; ユビキチン化; Mad1; EB1

The spindle checkpoint is a surveillance mechanism that ensures equal segregation of chromosomes in mitosis. From prophase to metaphase it delays sister chromatid separation until all the kinetochores are connected to the mitotic spindles. In this research project we focused on Mad2, a protein which plays a central role in the signal cascade of the spindle checkpoint and attempted to reveal its biochemical nature as well as a molecular mechanism to negatively regulate Mad2.We found that Mad2 adopts two distinct folded conformations at equilibrium (termed N1-Mad2 and N2-Mad2). N2-Mad2 is more potent in APC/C inhibition. The two Mad2 conformers interconvert slowly in vitro, but interconversion is accelerated by a fragment of Mad1, an upstream regulator of Mad2. We also demonstrated that a negative regulator p31comet selectively interacts with N2-Mad2. Biochemical analysis of p31comet allowed identification of DNCI (intermediate chain of dynein) as a binding partner of p31comet. The two proteins physically interact each other in late mitosis. Cells lacking DNCI were arrested at metaphase with properly aligned chromosomes at the metaphase plate. This phenotype would suggest that DNCI together with p31comet play an important role in silencing the spindle checkpoint.

纺锤体检查点是一种监视机制，确保有丝分裂中染色体的平等分离。从前期到中期，它延迟姐妹染色单体的分离，直到所有的动粒都连接到有丝分裂的纺锤体上。本研究以Mad 2蛋白为研究对象，试图揭示Mad 2蛋白的生物化学性质以及负调控Mad 2的分子机制。N2-Mad 2在APC/C抑制中更有效。这两个Mad 2构象在体外缓慢相互转化，但相互转化是由Mad 1，Mad 2的上游调节器的片段加速。我们还证明了负调节p31 comet选择性地与N2-Mad 2相互作用。p31 comet的生化分析允许鉴定DNCI（动力蛋白的中间链）作为p31 comet的结合伴侣。这两种蛋白质在有丝分裂后期相互作用。缺乏DNCI的细胞被阻滞在中期，染色体在中期板上正确排列。这种表型表明DNCI与p31彗星一起在沉默纺锤体检查点中起重要作用。

项目成果

Low concentrations of taxol cause mitotic delay followed by premature dissociation of p55CDC from mad2 and BubR1 and abrogation of the spindle checkpoint, leading to aneuploidy

• DOI: 10.4161/cc.4.10.2061
• 发表时间: 2005-10-01
• 期刊: CELL CYCLE
• 影响因子: 4.3
• 作者: Ikui, AE;Yang, CPH;Horwitz, SB
• 通讯作者: Horwitz, SB

Luo X., Tang Z., Xia, G., Wassmann K., Matsumoto T., Rizo, J., Yu H: "Conformational signaling by Mad2 in the mitotic spindle checkpoint"Nature Structural & Molecular Biology. (In press). (2004)

Luo X.，Tang Z.，Xia，G.，Wassmann K.，Matsumoto T.，Rizo，J.，Yu H：“有丝分裂纺锤体检查点中 Mad2 的构象信号”Nature Structural

Conformation-specific binding of p31^comet to Mad2 antagonizes the function of Mad2 in the spindle checkpoint.

p31^comet 与 Mad2 的构象特异性结合拮抗 Mad2 在纺锤体检查点中的功能。

• 发表时间: 2004
• 期刊: EMBO J. 23
• 作者: Xia;G.et al.
• 通讯作者: G.et al.

The dream of every chromosome ; equal segregation for a healthy life of the host. Genome Instability and Cancer Development, in Advances in Experimental Medicine and Biology

每一条染色体的梦想；

• 发表时间: 2005
• 作者: Matsumoto;T.;et al.
• 通讯作者: et al.

Conformational signaling by Mad2 in the mitotic spindle checkpoint

有丝分裂纺锤体检查点中 Mad2 的构象信号传导

• 发表时间: 2004
• 期刊: Nature Structural & Molecular Biology 11
• 作者: Luo X.;Tang Z.;Xia;G.;Wassmann X.;Matsumoto T.;Rizo;J.;Yu H
• 通讯作者: Yu H