Role of the Mad2 Dimerization Interface in the Spindle Assembly Checkpoint Independent of Kinetochores
Role of the Mad2 Dimerization Interface in the Spindle Assembly Checkpoint Independent of Kinetochores
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DOI：
10.1016/j.cub.2012.08.028
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发表时间：
2012-10-23
期刊：
影响因子：
9.2
通讯作者：
Ciliberto, Andrea
中科院分区：
文献类型：
--
作者：
Mariani, Luca;Chiroli, Elena;Ciliberto, Andrea
背景：当着丝粒与纺锤体微管分离时，纺锤体组装检查点（SAC）使细胞停滞。信号传导途径在着丝粒处由一个SAC组分Mad2启动，其通过其开放和封闭构象异构体的构象二聚化催化级联的初始步骤。远离动粒，Mad2的二聚化表面已被提出，基于体外数据，与SAC激活剂或灭活剂相互作用，从而有助于SAC激活或沉默。在这里，我们分析它的作用在vivo.Results：要分析下游的着丝粒的推定途径，我们使用了两种互补的方法：我们激活SAC异位和独立的着丝粒，我们分离基因的着丝粒依赖和独立的池Mad2。我们发现，二聚化表面也需要下游的动粒安装checkpoint respons.Conclusion：我们的研究结果表明，远离动粒的二聚化表面是需要稳定的最终产品的途径，有丝分裂检查点复合物。令人惊讶的是，动粒的下游表面不介导Mad2二聚化。相反，我们的研究结果是一致的Mad3作为Mad2通过二聚化表面的主要相互作用的作用。
Background: The spindle assembly checkpoint (SAC) arrests cells when kinetochores are unattached to spindle microtubules. The signaling pathway is initiated at the kinetochores by one SAC component, Mad2, which catalyzes the initial steps of the cascade via the conformational dimerization of its open and closed conformers. Away from kinetochores, the dimerization surface of Mad2 has been proposed, based on data in vitro, to either interact with SAC activators or inactivators and thus to contribute to SAC activation or silencing. Here, we analyze its role in vivo.Results: To analyze the putative pathway downstream of the kinetochores, we used two complementary approaches: we activated the SAC ectopically and independently from kinetochores, and we separated genetically the kinetochore-dependent and independent pools of Mad2. We found that the dimerization surface is required also downstream of kinetochores to mount a checkpoint response.Conclusion: Our results show that away from kinetochores the dimerization surface is required for stabilizing the end-product of the pathway, the mitotic checkpoint complex. Surprisingly, downstream of kinetochores the surface does not mediate Mad2 dimerization. Instead, our results are consistent with a role of Mad3 as the main interactor of Mad2 via the dimerization surface.