Mlp1 Acts as a Mitotic Scaffold to Spatially Regulate Spindle Assembly Checkpoint Proteins in Aspergillus nidulans
Mlp1 Acts as a Mitotic Scaffold to Spatially Regulate Spindle Assembly Checkpoint Proteins in Aspergillus nidulans
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DOI：
10.1091/mbc.e08-08-0878
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发表时间：
2009-04-15
影响因子：
3.3
通讯作者：
Osmani, Stephen A.
中科院分区：
文献类型：
--
作者：
De Souza, Colin P.;Hashmi, Shahr B.;Osmani, Stephen A.
在开放有丝分裂过程中，一些核孔复合物（NPC）蛋白具有有丝分裂特异性定位和功能。我们发现构巢曲霉Mlp 1 NPC蛋白具有以前未实现的有丝分裂作用，涉及纺锤体组装检查点（SAC）蛋白的空间调控。在间期，An-Mlp 1将An-Mad 1和An-Mad 2 SAC蛋白拴系到NPC。在正常的有丝分裂过程中，An-Mlp 1，An-Mad 1和An-Mad 2定位类似，周围，着丝粒，直到末期时，他们短暂定位在纺锤体附近，但不是在着丝粒。在SAC激活期间，An-Mlp 1以类似于An-Mad 1和An-Mad 2的方式与着丝粒保持关联。虽然An-Mlp 1是不需要的An-Mad 1动粒定位在早期有丝分裂，它是必不可少的，以维持An-Mad 1在周围的扩展区域的动粒在早期有丝分裂和附近的纺锤体在末期。我们的数据是一致的An-Mlp 1的有丝分裂纺锤体矩阵的一部分，类似于其果蝇的直系同源物，并表明该矩阵本地化SAC蛋白。通过维持SAC蛋白靠近有丝分裂器，An-Mlp 1可能有助于监测有丝分裂进程和协调有效的有丝分裂退出。与这种可能性相一致，An-Mad 1和An-Mlp 1从末期基质中重新分布，并在有丝分裂退出被不可降解的细胞周期蛋白B的表达阻止时与分离的动粒相关联。
During open mitosis several nuclear pore complex (NPC) proteins have mitotic specific localizations and functions. We find that the Aspergillus nidulans Mlp1 NPC protein has previously unrealized mitotic roles involving spatial regulation of spindle assembly checkpoint (SAC) proteins. In interphase, An-Mlp1 tethers the An-Mad1 and An-Mad2 SAC proteins to NPCs. During a normal mitosis, An-Mlp1, An-Mad1, and An-Mad2 localize similarly on, and around, kinetochores until telophase when they transiently localize near the spindle but not at kinetochores. During SAC activation, An-Mlp1 remains associated with kinetochores in a manner similar to An-Mad1 and An-Mad2. Although An-Mlp1 is not required for An-Mad1 kinetochore localization during early mitosis, it is essential to maintain An-Mad1 in the extended region around kinetochores in early mitosis and near the spindle in telophase. Our data are consistent with An-Mlp1 being part of a mitotic spindle matrix similar to its Drosophila orthologue and demonstrate that this matrix localizes SAC proteins. By maintaining SAC proteins near the mitotic apparatus, An-Mlp1 may help monitor mitotic progression and coordinate efficient mitotic exit. Consistent with this possibility, An-Mad1 and An-Mlp1 redistribute from the telophase matrix and associate with segregated kinetochores when mitotic exit is prevented by expression of nondegradable cyclin B.