Phosphorylation of myosin II regulatory light chain controls its accumulation, not that of actin, at the contractile ring in HeLa cells.
Phosphorylation of myosin II regulatory light chain controls its accumulation, not that of actin, at the contractile ring in HeLa cells.
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DOI：
10.1016/j.yexcr.2012.02.009
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发表时间：
2012-05
影响因子：
3.7
通讯作者：
Tomo Kondo;S. Itakura;Kozue Hamao;H. Hosoya
中科院分区：
文献类型：
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作者：
Tomo Kondo;S. Itakura;Kozue Hamao;H. Hosoya
在真核细胞的细胞质分裂过程中，一个基于肌动球蛋白的收缩环（CR）沿着细胞的赤道组装。体外实验中Myosin II调节轻链（MRLC）的磷酸化可刺激Myosin II atp酶活性，并且在各种类型的细胞中，磷酸化的MRLC定位于CR。先前的研究已经确定磷酸化的MRLC在CR犁沟中起重要作用。然而，磷酸化的MRLC在CR组装中的作用仍然未知。在这里，我们使用共聚焦显微镜观察了在皮层附近的CR组装过程中表达荧光蛋白标记的MRLC突变体和肌动蛋白的HeLa细胞的分裂。二磷酰亚胺MRLC比非磷酸化MRLC和肌动蛋白更早在细胞赤道积累。有趣的是，通过非磷酸化MRLC表达或用blebbistatin（一种肌球蛋白II抑制剂）治疗来干扰肌动蛋白II活性，并没有改变肌动蛋白在细胞赤道积聚的时间。此外，latrunculin A对肌动蛋白聚合的抑制作用对细胞赤道处MRLC的积累没有影响。综上所述，这些数据表明，在培养的哺乳动物细胞中，磷酸化的MRLC暂时控制其自身的积累，而不是肌动蛋白的积累。
During cytokinesis in eukaryotic cells, an actomyosin-based contractile ring (CR) is assembled along the equator of the cell. Myosin II ATPase activity is stimulated by the phosphorylation of the myosin II regulatory light chain (MRLC) in vitro, and phosphorylated MRLC localizes at the CR in various types of cells. Previous studies have determined that phosphorylated MRLC plays an important role in CR furrowing. However, the role of phosphorylated MRLC in CR assembly remains unknown. Here, we have used confocal microscopy to observe dividing HeLa cells expressing fluorescent protein-tagged MRLC mutants and actin during CR assembly near the cortex. Di-phosphomimic MRLC accumulated at the cell equator earlier than non-phosphorylatable MRLC and actin. Interestingly, perturbation of myosin II activity by non-phosphorylatable MRLC expression or treatment with blebbistatin, a myosin II inhibitor, did not alter the time of actin accumulation at the cell equator. Furthermore, inhibition of actin polymerization by treatment with latrunculin A had no effect on MRLC accumulation at the cell equator. Taken together, these data suggest that phosphorylated MRLC temporally controls its own accumulation, but not that of actin, in cultured mammalian cells.