Differential contributions of nonmuscle myosin IIA and IIB to cytokinesis in human immortalized fibroblasts
Differential contributions of nonmuscle myosin IIA and IIB to cytokinesis in human immortalized fibroblasts
复制标题
非肌肉肌球蛋白 IIA 和 IIB 对人永生化成纤维细胞胞质分裂的不同贡献
DOI：
10.1016/j.yexcr.2019.01.020
复制
发表时间：
2019
影响因子：
3.7
通讯作者：
M.
中科院分区：
文献类型：
--
作者：
Yamamoto;K.;Otomo;K.;Nemoto;T.;Ishihara;S.;Haga;H.;Nagasaki;A.;Murakami;Y.;Takahashi;M.
非肌肉肌球蛋白II(NMII)通过收缩收缩环在胞质分裂中发挥重要作用。然而，人们对NMII亚型如何促进哺乳动物细胞胞质分裂知之甚少。在这里，我们研究了两个主要的NMII亚型，NMIIA和NMIIB，在细胞质分裂中的作用，使用的是WI-38VA13细胞系(人永生化成纤维细胞)。在该细胞系中，NMIIB比NMIIA更倾向于定位于收缩环。NMIIA的表达水平影响NMIIB的定位。在NMIIA基因敲除(KO)细胞中，大多数NMIIB聚集在卵裂沟，而在外源表达NMIIB的细胞中，大多数NMIIA从这个位置移位，表明NMIIB优先定位于收缩环。每种异构体的特定KO均产生相反的效应。NMIIA-KO和NMIIB-KO细胞的沟槽侵入率分别降低和增加。同时，NMIIA-KO和NMIIB-KO细胞收缩环上的NMII-纤维堆叠长度分别增加和减少。此外，NMIIA有助于在胞质分裂过程中保持皮质硬度。这些发现表明，在特定类型的细胞中，适当的NMIIA和NMIIB在收缩环中的比例对于适当的胞质分裂是重要的。此外，双光子激发旋转圆盘共聚焦显微镜使我们能够以三维的方式成像活细胞中收缩环的收缩。
Nonmuscle myosin II (NMII) plays an important role in cytokinesis by constricting a contractile ring. However, it is poorly understood how NMII isoforms contribute to cytokinesis in mammalian cells. Here, we investigated the roles of the two major NMII isoforms, NMIIA and NMIIB, in cytokinesis using a WI-38 VA13 cell line (human immortalized fibroblast). In this cell line, NMIIB tended to localize to the contractile ring more than NMIIA. The expression level of NMIIA affected the localization of NMIIB. Most NMIIB accumulated at the cleavage furrow in NMIIA-knockout (KO) cells, and most NMIIA was displaced from this location in exogenous NMIIB-expressing cells, indicating that NMIIB preferentially localizes to the contractile ring. Specific KO of each isoform elicited opposite effects. The rate of furrow ingression was decreased and increased in NMIIA-KO and NMIIB-KO cells, respectively. Meanwhile, the length of NMII-filament stacks in the contractile ring was increased and decreased in NMIIA-KO and NMIIB-KO cells, respectively. Moreover, NMIIA helped to maintain cortical stiffness during cytokinesis. These findings suggest that appropriate ratio of NMIIA and NMIIB in the contractile ring is important for proper cytokinesis in specific cell types. In addition, two-photon excitation spinning-disk confocal microscopy enabled us to image constriction of the contractile ring in live cells in a three-dimensional manner.