Microtubule network remodeling is an essential process for cell development, maintenance, cell division, and motility. Microtubule‐severing enzymes are key players in the remodeling of the microtubule network; however, there are still open questions about their fundamental biochemical and biophysical mechanisms. Here, we explored the ability of the microtubule‐severing enzyme katanin to depolymerize stabilized microtubules. Interestingly, we found that the tubulin C‐terminal tail (CTT), which is required for severing, is not required for katanin‐catalyzed depolymerization. We also found that the depolymerization of microtubules lacking the CTT does not require ATP or katanin's ATPase activity, although the ATP turnover enhanced depolymerization. We also observed that the depolymerization rate depended on the katanin concentration and was best described by a hyperbolic function. Finally, we demonstrate that katanin can bind to filaments that lack the CTT, contrary to previous reports. The results of our work indicate that microtubule depolymerization likely involves a mechanism in which binding, but not enzymatic activity, is required for tubulin dimer removal from the filament ends.

中文翻译：

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Katanin独立于微管蛋白C末端尾部催化微管解聚。

微管网络重塑是细胞发育，维持，细胞分裂和运动的重要过程。分离微管的酶是微管网络重塑的关键因素。然而，关于它们的基本生化和生物物理机制仍存在未解决的问题。在这里，我们探讨了微管切割酶katanin解聚稳定的微管的能力。有趣的是，我们发现，切断所必需的微管蛋白C末端尾巴（CTT）不需要用于katanin催化的解聚反应。我们还发现，尽管ATP转换增强了解聚作用，但缺乏CTT的微管解聚不需要ATP或katanin的ATPase活性。我们还观察到解聚速率取决于katanin的浓度，并且最好用双曲线函数来描述。最后，与以前的报道相反，我们证明了katanin可以结合缺乏CTT的细丝。我们的工作结果表明，微管解聚可能涉及一种机制，其中从细丝末端去除微管蛋白二聚体需要结合而不是酶促活性。