Cortical actin turnover during cytokinesis requires myosin II
Cortical actin turnover during cytokinesis requires myosin II
复制标题
DOI：
10.1016/j.cub.2005.03.042
复制
发表时间：
2005-04-26
期刊：
影响因子：
9.2
通讯作者：
Wang, YL
中科院分区：
文献类型：
--
作者：
Guha, M;Zhou, M;Wang, YL
肌球蛋白II参与胞质分裂已被证明与显微注射，遗传和药理学方法，然而，肌球蛋白II在细胞分裂中的确切作用仍然知之甚少。为了解决这个问题，我们用blebbistatin（一种有效的非肌肉肌球蛋白II ATP酶抑制剂）处理分裂的正常大鼠肾（NRK）细胞。Blebbistatin引起了强烈的抑制胞质分裂，但没有检测到的影响赤道定位的肌动蛋白或肌球蛋白。然而，尽管这些丝在后期胞质分裂过程中从对照细胞的赤道分离，但它们在blebbistatin处理的细胞中持续了很长一段时间。赤道肌动蛋白的积累是由肌动蛋白丝营业额的抑制，荧光光漂白后的恢复半衰期增加2倍。局部释放blebbistatin在赤道引起局部积累的赤道肌动蛋白和抑制胞质分裂，符合肌球蛋白II沿着沟的功能。然而，极区的治疗也引起了高频率的异常胞质分裂，这表明肌球蛋白II可能发挥第二个，全球性的作用。我们的观察表明，肌球蛋白II ATP酶不是胞质分裂期间赤道皮质组装所需的，但对其随后的周转和重塑至关重要。
The involvement of myosin II in cytokinesis has been demonstrated with microinjection, genetic, and pharmacological approaches; however, the exact role of myosin II in cell division remains poorly understood. To address this question, we treated dividing normal rat kidney (NRK) cells with blebbistatin, a potent inhibitor of the nonmuscle myosin II ATPase. Blebbistatin caused a strong inhibition of cytokinesis but no detectable effect on the equatorial localization of actin or myosin. However, whereas these filaments dissociated from the equator in control cells during late cytokinesis, they persisted in blebbistatin-treated cells over an extended period of time. The accumulation of equatorial actin was caused by the inhibition of actin filament turnover, as suggested by a 2-fold increase in recovery half-time after fluorescence photobleaching. Local release of blebbistatin at the equator caused localized accumulation of equatorial actin and inhibition of cytokinesis, consistent with the function of myosin II along the furrow. However, treatment of the polar region also caused a high frequency of abnormal cytokinesis, suggesting that myosin II may play a second, global role. Our observations indicate that myosin II ATPase is not required for the assembly of equatorial cortex during cytokinesis but is essential for its subsequent turnover and remodeling.