Kinetic stabilization of microtubule dynamic instability in vitro by vinblastine.
Kinetic stabilization of microtubule dynamic instability in vitro by vinblastine.
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DOI：
10.1021/bi00056a013
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发表时间：
1993-02
期刊：
影响因子：
2.9
通讯作者：
R. Toso;M. Jordan;K. Farrell;B. Matsumoto;L. Wilson
中科院分区：
文献类型：
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作者：
R. Toso;M. Jordan;K. Farrell;B. Matsumoto;L. Wilson
低浓度长春碱的抗增殖作用似乎是由于纺锤体微管聚合动力学的调节而不是由于微管的去极化[Jordan，M.一、投掷者，D.，& Wilson，L. 51，2212-2222;（1992）J. Cell. Sci. 102，401-416]。在本研究中，我们使用微分干涉相差视频显微镜分析长春碱对生长和缩短动力学（动态不稳定性）的个别牛脑微管在体外的影响。对于缺乏微管相关蛋白（MAP）或富含MAP的微管，低浓度的长春碱（0.2 μ M-1 μ M）抑制了生长和缩短速率，并增加了微管处于减弱状态的时间百分比活动，既不生长也不缩短。可检测到。长春碱还抑制微管生长和缩短的持续时间，并增加衰减状态的持续时间，在此期间微管既不生长也不缩短。与先前在微管悬浮液中使用放射性标记的核苷酸交换获得的数据一致[Jordan，M.一、& Wilson，L.（1990）Biochemistry 29，2730-2739]，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GTP或GDP-Pi“帽”的增益和损失来动力学稳定微管末端，这被认为是负责生长和缩短阶段之间的过渡。数据支持以下假设：（1）低浓度长春碱通过动力学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。
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.