2-METHOXYESTRADIOL, AN ENDOGENOUS MAMMALIAN METABOLITE, INHIBITS TUBULIN POLYMERIZATION BY INTERACTING AT THE COLCHICINE SITE
2-METHOXYESTRADIOL, AN ENDOGENOUS MAMMALIAN METABOLITE, INHIBITS TUBULIN POLYMERIZATION BY INTERACTING AT THE COLCHICINE SITE
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DOI：
10.1073/pnas.91.9.3964
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发表时间：
1994-04-26
影响因子：
11.1
通讯作者：
HAMEL, E
中科院分区：
文献类型：
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作者：
DAMATO, RJ;LIN, CM;HAMEL, E
雌二醇的代谢产物2-甲氧基雌二醇（2 ME）在鸡胚绒毛尿囊膜试验中抑制血管生成。由于2 ME引起有丝分裂扰动，我们研究了它与微管蛋白的相互作用。在我们的标准1.0 M谷氨酸盐系统（加上1.0 mM MgCl 2，在37 ℃），超化学计量浓度（相对于微管蛋白）的2 ME抑制微管蛋白组件的成核和传播阶段，但不影响反应程度。尽管在2 ME存在下形成的聚合物比对照聚合物更冷稳定，但形态变化不大。在次优反应条件下（0.8M谷氨酸/无MgCl 2，26 ℃），亚化学计量的2 ME完全抑制聚合。没有其他雌激素化合物作为聚合或秋水仙素与微管蛋白结合的抑制剂，2 ME同样有效。秋水仙素结合的抑制是竞争性的（Ki，22 μ M）。因此，哺乳动物的雌二醇代谢物结合到微管蛋白的秋水仙碱位点，并且根据反应条件，抑制组装或似乎被掺入具有改变的稳定性的聚合物中。
A metabolite of estradiol, 2-methoxyestradiol (2ME), inhibits angiogenesis in the chicken embryo chorioallantoic membrane assay. Since 2ME causes mitotic perturbations, we examined its interactions with tubulin. In our standard 1.0 M glutamate system (plus 1.0 mM MgCl2 at 37 degrees C), superstoichiometric concentrations (relative to tubulin) of 2ME inhibited the nucleation and propagation phases of tubulin assembly but did not affect the reaction extent. Although polymer formed in the presence of 2ME was more cold-stable than control polymer, morphology was little changed. Under suboptimal reaction conditions (0.8 M glutamate/no MgCl2 at 26 degrees C), substoichiometric 2ME totally inhibited polymerization. No other estrogenic compound was as effective as 2ME as an inhibitor of polymerization or of the binding of colchicine to tubulin. Inhibition of colchicine binding was competitive (K-i, 22 mu M). Thus, a mammalian metabolite of estradiol binds to the colchicine site of tubulin and, depending on reaction conditions, either inhibits assembly or seems to be incorporated into a polymer with altered stability properties.