The ran GTPase regulates kinetochore function
The ran GTPase regulates kinetochore function
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DOI：
10.1016/s1534-5807(03)00194-1
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发表时间：
2003-07-01
影响因子：
11.8
通讯作者：
Dasso, M
中科院分区：
文献类型：
--
作者：
Arnaoutov, A;Dasso, M
Ran GTdR是核组装、核运输、纺锤体组装和有丝分裂调节所必需的。虽然前三个过程相对较好地理解，但Ran在有丝分裂进程中的作用的细节仍然不清楚。我们已经发现，Ran交换因子（RCC 1）的水平升高废除了非洲爪蟾卵提取物中的纺锤体组装检查点，恢复APC/C活性，并破坏检查点调节因子（包括Mad 2，CENP-E，Bub 1和Bub 3）的动粒定位。Ran's GT3激活蛋白（RanGAP 1）及其辅助因子（RanBP 1）的消耗同样消除了检查点阻滞。相比之下，RanGAP 1和RanBP 1与外源RCC 1的提取物的添加恢复纺锤体检查点。总之，这些观察结果表明纺锤体检查点直接响应于Ran-GTP水平。最后，我们观察到一个明确的波RCC 1协会有丝分裂染色体在中期-后期的过渡在正常的周期提取物，这表明这种机制有一个重要的作用，在未受干扰的细胞周期。
The Ran GTPase is required for nuclear assembly, nuclear transport, spindle assembly, and mitotic regulation. While the first three processes are relatively well understood, details of Ran's role in mitotic progression remain obscure. We have found that elevated levels of Ran's exchange factor (RCC1) abrogate the spindle assembly checkpoint in Xenopus egg extracts, restore APC/C activity, and disrupt the kinetochore localization of checkpoint regulators, including Mad2, CENP-E, Bub1, and Bub3. Depletion of Ran's GTPase activating protein (RanGAP1) and its accessory factor (RanBP1) similarly abrogates checkpoint arrest. By contrast, the addition of RanGAP1 and RanBP1 to extracts with exogenous RCC1 restores the spindle checkpoint. Together, these observations suggest that the spindle checkpoint is directly responsive to Ran-GTP levels. Finally, we observe a clear wave of RCC1 association to mitotic chromosomes at the metaphase-anaphase transition in normal cycling extracts, suggesting that this mechanism has an important role in unperturbed cell cycles.