Gliksman N R, Parsons S F, Salmon E D
Department of Biology, University of North Carolina, Chapel Hill 27599-3280.
J Cell Biol. 1992 Dec;119(5):1271-6. doi: 10.1083/jcb.119.5.1271.
We used high-resolution video microscopy to visualize microtubule dynamic instability in extracts of interphase sea urchin eggs and to analyze the changes that occur upon addition of 0.8-2.5 microM okadaic acid, an inhibitor of phosphatase 1 and 2A (PP1, PP2a) (Bialojan, D., and A. Takai. 1988. Biochem. J. 256:283-290). Microtubule plus-ends in these extracts oscillated between the elongation and shortening phases of dynamic instability at frequencies typical for interphase cells. Switching from elongation to shortening (catastrophe) was frequent, but microtubules persisted and grew long because of frequent switching back to elongation (rescue). Addition of okadaic acid to the extract induced rapid (< 5 min) conversion to short, dynamic microtubules typical of mitosis. The frequency of catastrophe doubled and the velocities of elongation and shortening increased slightly; however, the major change was an elimination of rescue. Thus, modulation of the rescue frequency by phosphorylation-dependent mechanisms may be a major regulatory pathway for selectively controlling microtubule dynamics without dramatically changing velocities of microtubule elongation and shortening.
我们使用高分辨率视频显微镜观察海胆卵间期提取物中的微管动态不稳定性，并分析添加0.8 - 2.5微摩尔冈田酸（一种磷酸酶1和2A（PP1、PP2a）的抑制剂）后发生的变化（比亚洛扬，D.，和A. 高井。1988年。《生物化学杂志》256:283 - 290）。这些提取物中的微管正端在动态不稳定性的伸长和缩短阶段之间振荡，频率与间期细胞的典型频率相同。从伸长转换为缩短（灾难）很频繁，但由于频繁转换回伸长（救援），微管持续存在并生长很长。向提取物中添加冈田酸会导致快速（<5分钟）转变为有丝分裂典型的短而动态的微管。灾难频率翻倍，伸长和缩短速度略有增加；然而，主要变化是救援的消除。因此，通过磷酸化依赖机制调节救援频率可能是一种主要的调节途径，用于在不大幅改变微管伸长和缩短速度的情况下选择性地控制微管动力学。
