Promotion of tubulin assembly by aluminum ion in vitro.
Promotion of tubulin assembly by aluminum ion in vitro.
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DOI：
10.1126/science.3105058
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发表时间：
1987-04
期刊：
影响因子：
56.9
通讯作者：
T. L. Macdonald;W. Humphreys;R. B. Martin
中科院分区：
文献类型：
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作者：
T. L. Macdonald;W. Humphreys;R. B. Martin
有人提出，铝离子是多种神经系统疾病的促成因素。在许多此类疾病中，细胞骨架的畸变已被注意到。通过测定聚合所需的金属离子-鸟苷三磷酸-微管蛋白三元复合物的缔合常数，研究了铝离子对微管蛋白体外组装成微管的影响。铝离子的缔合常数大约是微管组装的生理介质镁离子的10(7)倍。此外，当镁离子低于1.0毫摩尔/升时，4.0×10(-10)摩尔/升的铝离子与镁离子有效竞争支持微管蛋白聚合。通过电子显微镜观察，铝离子产生的微管与镁离子产生的微管没有区别，并且它们表现出相同的组装临界微管蛋白浓度和对冷诱导解聚的敏感性。然而，铝离子微管的三磷酸鸟苷水解速率和对钙离子诱导的解聚（体内微管的关键调节过程）的敏感性明显低于镁离子微管。
It has been proposed that aluminum ion is a contributing factor in a variety of neurological diseases. In many of these diseases, aberrations in the cytoskeleton have been noted. The effects of aluminum ion on the in vitro assembly of tubulin into microtubules has been examined by determining the association constants for the metal ion-guanosine triphosphate-tubulin ternary complex required for polymerization. The association constant for aluminum ion was approximately 10(7) times that of magnesium ion, the physiological mediator of microtubule assembly. In addition, aluminum ion at 4.0 X 10(-10) mole per liter competed effectively with magnesium ion for support of tubulin polymerization when magnesium ion falls below 1.0 millimole per liter. The microtubules produced by aluminum ion were indistinguishable from those produced by magnesium ion when viewed by electron microscopy, and they showed identical critical tubulin concentrations for assembly and sensitivities to cold-induced depolymerization. However, the rate of guanosine triphosphate hydrolysis and the sensitivity to calcium ion-induced depolymerization, critical regulatory processes of microtubules in vivo, were markedly lower for aluminum ion microtubules than for magnesium ion microtubules.