JNK2 controls fragmentation of the Golgi complex and the G2/M transition through phosphorylation of GRASP65
JNK2 controls fragmentation of the Golgi complex and the G2/M transition through phosphorylation of GRASP65
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DOI：
10.1242/jcs.164871
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发表时间：
2015-06-15
影响因子：
4
通讯作者：
Colanzi, Antonino
中科院分区：
文献类型：
--
作者：
Cervigni, Romina Ines;Bonavita, Raffaella;Colanzi, Antonino
在哺乳动物细胞中，高尔基复合体由膜小管连接的堆叠组成。在G2期间，高尔基复合体被分解为孤立的堆栈。这个过程是进入有丝分裂所必需的，表明细胞器的正确遗传是由“高尔基体有丝分裂检查点”监控的。然而，这种高尔基体解体的调控和分子机制仍然知之甚少。在这里，我们表明，JNK 2在G2特异性分离的高尔基体堆叠通过磷酸化的高尔基体堆叠蛋白GRASP 65（也称为GORASP 1）的Ser 277的至关重要的作用。通过RNA干扰或通过用三种不相关的JNK抑制剂处理抑制JNK 2导致G2中的有效和持久的细胞周期阻滞。如果高尔基复合体被布雷菲德菌素A处理或GRASP 65耗竭分解，JNK活性变得不适合有丝分裂进入。最后，测量的高尔基体荧光恢复后，光漂白表明，JNK是必需的连接高尔基体堆栈的小管的分裂。我们的研究结果表明，JNK 2-GRASP 65信号轴在耦合高尔基体遗传和G2/M转换中起着至关重要的作用。
In mammalian cells, the Golgi complex is composed of stacks that are connected by membranous tubules. During G2, the Golgi complex is disassembled into isolated stacks. This process is required for entry into mitosis, indicating that the correct inheritance of the organelle is monitored by a 'Golgi mitotic checkpoint'. However, the regulation and the molecular mechanisms underlying this Golgi disassembly are still poorly understood. Here, we show that JNK2 has a crucial role in the G2-specific separation of the Golgi stacks through phosphorylation of Ser277 of the Golgi-stacking protein GRASP65 (also known as GORASP1). Inhibition of JNK2 by RNA interference or by treatment with three unrelated JNK inhibitors causes a potent and persistent cell cycle block in G2. JNK activity becomes dispensable for mitotic entry if the Golgi complex is disassembled by brefeldin A treatment or by GRASP65 depletion. Finally, measurement of the Golgi fluorescence recovery after photobleaching demonstrates that JNK is required for the cleavage of the tubules connecting Golgi stacks. Our findings reveal that a JNK2-GRASP65 signalling axis has a crucial role in coupling Golgi inheritance and G2/M transition.