Toso R J, Jordan M A, Farrell K W, Matsumoto B, Wilson L
Department of Biological Sciences, University of California, Santa Barbara 93106.
Biochemistry. 1993 Feb 9;32(5):1285-93. doi: 10.1021/bi00056a013.
The antiproliferative action of vinblastine at low concentrations appears to result from modulation of the polymerization dynamics of spindle microtubules rather than from depolarization of the microtubules [Jordan, M. A., Thrower, D., & Wilson, L. (1991) Cancer Res. 51, 2212-2222; (1992) J. Cell. Sci. 102, 401-416]. In the present study, we used differential interference contrast video microscopy to analyze the effects of vinblastine on the growing and shortening dynamics (dynamic instability) of individual bovine brain microtubules in vitro. With microtubules which were either depleted of microtubule-associated proteins (MAPs) or rich in MAPs, low concentrations of vinblastine (0.2 microM-1 microM) suppressed the growing and shortening rates and increased the percentage of time that the microtubules spent a state of attenuated activity, neither growing nor shortening detectably. Vinblastine also suppressed the duration of microtubule growing and shortening, and increased the duration of the attenuated state, during which the microtubules neither grew nor shortened detectably. Consistent with previous data obtained using radiolabeled nucleotide exchange in microtubule suspensions [Jordan, M. A., & Wilson, L. (1990) Biochemistry 29, 2730-2739], vinblastine suppressed growing and shortening dynamics at the kinetically more rapid plus ends. The results suggest that vinblastine kinetically stabilizes microtubule ends by modulating the gain and loss of the stabilizing GTP or GDP-Pi "cap", which is believed to be responsible for the transitions between the growing and shortening phases. The data support the hypothesis that (1) low concentrations of vinblastine inhibit mitosis by kinetically stabilizing the polymerization dynamics of spindle microtubules and that (2) the dynamics of spindle microtubules are critical for the proper progression of mitosis.
长春碱在低浓度时的抗增殖作用似乎源于对纺锤体微管聚合动力学的调节，而非微管的去极化作用[乔丹，M. A.，思罗尔，D.，& 威尔逊，L.（1991年）《癌症研究》51卷，2212 - 2222页；（1992年）《细胞科学杂志》102卷，401 - 416页]。在本研究中，我们使用微分干涉相差视频显微镜来分析长春碱对体外单个牛脑微管生长和缩短动力学（动态不稳定性）的影响。对于那些微管相关蛋白（MAPs）耗尽或富含MAPs的微管，低浓度的长春碱（0.2微摩尔/升 - 1微摩尔/升）会抑制生长和缩短速率，并增加微管处于活性减弱状态（既不明显生长也不明显缩短）的时间百分比。长春碱还会抑制微管生长和缩短的持续时间，并增加减弱状态的持续时间，在此期间微管既不明显生长也不明显缩短。与之前在微管悬浮液中使用放射性标记核苷酸交换获得的数据一致[乔丹，M. A.，& 威尔逊，L.（1990年）《生物化学》29卷，2730 - 2739页]，长春碱在动力学上更快的正端抑制生长和缩短动力学。结果表明，长春碱通过调节稳定的GTP或GDP - Pi“帽”的获得和丢失，在动力学上稳定微管末端，据信这种“帽”负责生长和缩短阶段之间的转变。这些数据支持以下假设：（1）低浓度的长春碱通过在动力学上稳定纺锤体微管的聚合动力学来抑制有丝分裂，以及（2）纺锤体微管的动力学对于有丝分裂的正常进行至关重要。
