Native kinesin-1 does not bind preferentially to GTP-tubulin-rich microtubules in vitro.
Native kinesin-1 does not bind preferentially to GTP-tubulin-rich microtubules in vitro.
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天然驱动蛋白-1 在体外不会优先与富含 GTP 微管蛋白的微管结合。
DOI：
10.1002/cm.21386
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
Xu,Jing
中科院分区：
文献类型：
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作者：
Li,Qiaochu;King,StephenJ;Xu,Jing
像Kinesin-1这样的分子马达以小团队的形式工作，在细胞内主动运送货物，例如在轴突的极化运输中。在这里，我们研究了微管蛋白的核苷酸状态对由多个动蛋白马达携带的货物的运行长度的潜在调节作用，使用基于光学捕获的体外试验。根据先前的一份报告，Kinesin优先结合到富含GTP微管的微管上，我们预计多Kinesin货物将沿着GMPCPP微管比沿着GDP微管运行的距离要大得多。令人惊讶的是，我们没有发现微管类型之间在运行长度上的任何显著差异。单分子实验、与以前理论的比较和经典的微管亲和力下拉分析相结合的结果表明，天然的Kinesin-1不优先与富含GTP微管的微管结合。我们的观察结果与之前的报告之间的明显差异可能反映了这里使用的本地马达和之前检查的重组马达之间的翻译后修饰的差异。未来的研究将有助于阐明马达的翻译后修饰和微管的核苷酸结合状态之间的相互作用，以调节体内的运输。
Molecular motors such as kinesin‐1 work in small teams to actively shuttle cargos in cells, for example in polarized transport in axons. Here, we examined the potential regulatory role of the nucleotide state of tubulin on the run length of cargos carried by multiple kinesin motors, using an optical trapping‐based in vitro assay. Based on a previous report that kinesin binds preferentially to GTP‐tubulin‐rich microtubules, we anticipated that multiple‐kinesin cargos would run substantially greater distances along GMPCPP microtubules than along GDP microtubules. Surprisingly, we did not uncover any significant differences in run length between microtubule types. A combination of single‐molecule experiments, comparison with previous theory, and classic microtubule affinity pulldown assays revealed that native kinesin‐1 does not bind preferentially to GTP‐tubulin‐rich microtubules. The apparent discrepancy between our observations and the previous report likely reflects differences in post‐translational modifications between the native motors used here and the recombinant motors examined previously. Future investigations will help shed light on the interplay between the motor's post‐translational modification and the microtubule's nucleotide‐binding state for transport regulation in vivo.