Kinesin Kip2 enhances microtubule growth in vitro through length-dependent feedback on polymerization and catastrophe
Kinesin Kip2 enhances microtubule growth in vitro through length-dependent feedback on polymerization and catastrophe
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DOI：
10.7554/elife.10542
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发表时间：
2015-11-18
期刊：
影响因子：
7.7
通讯作者：
Howard, Jonathan
中科院分区：
文献类型：
--
作者：
Hibbel, Anneke;Bogdanova, Aliona;Howard, Jonathan
有丝分裂纺锤体的大小和位置由其组成微管的长度决定。微管长度的调节需要反馈来设定生长和收缩之间的平衡。尽管基于解聚驱动蛋白和切断蛋白质的微管长度控制的负反馈机制已被广泛研究，但正反馈机制尚不清楚。在这里，我们报告说，芽殖酵母驱动蛋白Kip2是一种微管聚合酶和突变抑制剂在体外，使用其进行性运动活动的反馈回路的一部分，以进一步促进微管生长。正反馈的出现是因为更长的微管结合了更多的马达，这些马达走到末端，在那里它们加强了生长并抑制了灾难。我们提出，正反馈，常见的生化途径之间的信号状态的切换，也可以用于机械信号通路之间的结构状态，在这种情况下，短和长的聚合物之间的切换。
The size and position of mitotic spindles is determined by the lengths of their constituent microtubules. Regulation of microtubule length requires feedback to set the balance between growth and shrinkage. Whereas negative feedback mechanisms for microtubule length control, based on depolymerizing kinesins and severing proteins, have been studied extensively, positive feedback mechanisms are not known. Here, we report that the budding yeast kinesin Kip2 is a microtubule polymerase and catastrophe inhibitor in vitro that uses its processive motor activity as part of a feedback loop to further promote microtubule growth. Positive feedback arises because longer microtubules bind more motors, which walk to the ends where they reinforce growth and inhibit catastrophe. We propose that positive feedback, common in biochemical pathways to switch between signaling states, can also be used in a mechanical signaling pathway to switch between structural states, in this case between short and long polymers.