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Single depolymerizing and transport kinesins stabilize microtubule ends
Cytoskeleton ( IF 2.9 ) Pub Date : 2021-07-26 , DOI: 10.1002/cm.21681
Alexandra Ciorîță 1, 2 , Michael Bugiel 1 , Swathi Sudhakar 1, 3 , Erik Schäffer 1 , Anita Jannasch 1
Affiliation  

Microtubules are highly dynamic cellular filaments and an accurate control of their length is important for many intracellular processes like cell division. Among other factors, microtubule length is actively modulated by motors from the kinesin superfamily. For example, yeast kinesin-8, Kip3, motors depolymerize microtubules by a cooperative, force- and length-dependent mechanism. However, whether single motors can also depolymerize microtubules is unclear. Here, we measured how single kinesin motors influenced the stability of microtubules in an in vitro assay. Using label-free interference reflection microscopy, we determined the spontaneous microtubule depolymerization rate of stabilized microtubules in the presence of kinesins. Surprisingly, we found that both single Kip3 and nondepolymerizing kinesin-1 transport motors, used as a control, stabilized microtubules further. For Kip3, this behavior is contrary to the collective force-dependent depolymerization activity of multiple motors. Because of the control measurement, the finding may hint at a more general stabilization mechanism. The complex, concentration-dependent interaction with microtubule ends provides new insights into the molecular mechanism of kinesin-8 and its regulatory function of microtubule length.

中文翻译:

单个解聚和运输驱动蛋白稳定微管末端

微管是高度动态的细胞细丝,准确控制其长度对于许多细胞内过程(如细胞分裂)很重要。除其他因素外,微管长度由驱动蛋白超家族的马达主动调节。例如,酵母 kinesin-8,Kip3,马达通过合作、力和长度依赖性机制解聚微管。然而,单个电机是否也可以解聚微管尚不清楚。在这里,我们测量了单个驱动蛋白马达如何影响体外微管的稳定性化验。使用无标记干涉反射显微镜,我们确定了在驱动蛋白存在下稳定微管的自发微管解聚速率。令人惊讶的是,我们发现用作对照的单个 Kip3 和非解聚驱动蛋白 1 运输马达进一步稳定了微管。对于 Kip3,这种行为与多个电机的集体力依赖性解聚活动相反。由于控制测量,这一发现可能暗示了一种更普遍的稳定机制。与微管末端的复杂、浓度依赖性相互作用为 kinesin-8 的分子机制及其对微管长度的调节功能提供了新的见解。
更新日期:2021-08-25
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