Function of spindle microtubules in directing cortical movement and actin filament organization in dividing cultured cells.
Function of spindle microtubules in directing cortical movement and actin filament organization in dividing cultured cells.
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发表时间：
1996-08
影响因子：
4
通讯作者：
D. Fishkind;J. Silverman;Yu-li Wang
中科院分区：
文献类型：
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作者：
D. Fishkind;J. Silverman;Yu-li Wang
有丝分裂纺锤体长期以来被认为在细胞分裂过程中决定分裂沟的位置起着重要作用，然而对这一过程所涉及的机制知之甚少。一个有吸引力的假设是，纺锤体发出的信号可能在细胞分裂过程中诱导皮层结构的重组和肌动蛋白丝向赤道的运输。虽然这是一个重要的想法，但很少有实验能直接验证这个模型。在目前的研究中，我们使用了多种实验方法来确定正常细胞分裂过程中对关键皮层事件的微管依赖性影响，包括皮层流动、肌动蛋白丝的重新定向和收缩装置的形成。单颗粒跟踪实验表明，微管破坏药物诺可达唑诱导细胞表面受体在后期开始后的运动受到抑制，而微管稳定药物紫杉醇则导致受体运动的整体模式发生深刻变化。这些影响伴随着肌动蛋白细胞骨架组织的一系列相关变化。在诺可达唑处理的细胞中，皮层肌动蛋白丝的三维组织似乎比对照组更不有序。荧光检测线性二色性的测量表明，沿着纺锤轴的细丝排列减少。相反，在紫杉醇处理的细胞中，肌动蛋白丝在皮层腹侧和背侧表面沿赤道的排列增加，反映了表面受体的重新分布模式。综上所述，这些实验表明纺锤体微管参与了细胞分裂过程中表面受体的双极流动和肌动蛋白丝的重组，从而刺激了皮层细胞骨架成分的定位和组织组织培养细胞分裂的收缩装置。
The mitotic spindle has long been recognized to play an essential role in determining the position of the cleavage furrow during cell division, however little is known about the mechanisms involved in this process. One attractive hypothesis is that signals from the spindle may function to induce reorganization of cortical structures and transport of actin filaments to the equator during cytokinesis. While an important idea, few experiments have directly tested this model. In the present study, we have used a variety of experimental approaches to identify microtubule-dependent effects on key cortical events during normal cell cleavage, including cortical flow, reorientation of actin filaments, and formation of the contractile apparatus. Single-particle tracking experiments showed that the microtubule disrupting drug nocodazole induces an inhibition of the movements of cell surface receptors following anaphase onset, while the microtubule stabilizing drug taxol causes profound changes in the overall pattern of receptor movements. These effects were accompanied by a related set of changes in the organization of the actin cytoskeleton. In nocodazole-treated cells, the three-dimensional organization of cortical actin filaments appeared less ordered than in controls. Measurements with fluorescence-detected linear dichroism indicated a decrease in the alignment of filaments along the spindle axis. In contrast, actin filaments in taxol-treated cells showed an increased alignment along the equator on both the ventral and dorsal cortical surfaces, mirroring the redistribution pattern of surface receptors. Together, these experiments show that spindle microtubules are involved in directing bipolar flow of surface receptors and reorganization of actin filaments during cell division, thus acting as a stimulus for positioning cortical cytoskeletal components and organizing the contractile apparatus of dividing tissue culture cells.