A Common Substrate Recognition Mode Conserved between Katanin p60 and VPS4 Governs Microtubule Severing and Membrane Skeleton Reorganization
A Common Substrate Recognition Mode Conserved between Katanin p60 and VPS4 Governs Microtubule Severing and Membrane Skeleton Reorganization
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DOI：
10.1074/jbc.m110.108365
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发表时间：
2010-05-28
影响因子：
4.8
通讯作者：
Hiroaki, Hidekazu
中科院分区：
文献类型：
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作者：
Iwaya, Naoko;Kuwahara, Yohta;Hiroaki, Hidekazu
Katanin p60（kp 60）是一种微管切割酶，在细胞骨架重组过程中以ATP依赖的方式发挥重要作用。我们发现，从小鼠katanin p60（kp 60-NTD）的N端分离的一个单一的结构域结合微管蛋白。通过NMR确定了kp 60-NTD的溶液结构。虽然它们的序列相似性低至20%，但kp 60-NTD的结构与微管相互作用和运输（MIT）结构域的结构具有惊人的相似性，MIT结构域采用反平行的三链螺旋束。特别地，螺旋2和3的排列在kp 60-NTD和来自Vps 4的MIT结构域之间是很保守的，Vps 4是促进转运III膜骨架复合物所需的内体分选复合物的分解的同源蛋白。突变研究表明，由螺旋2和3形成的带正电荷的表面结合微管蛋白。这种结合模式类似于Vps 4的MIT结构域和Vps 2/CHMP 1a之间的相互作用，Vps 2/CHMP 1a是转运III所需的内体分选复合物的一种组分。我们的研究结果表明，无论是分子结构和结合模式是保守的两个AAA-ATP酶，kp 60和Vps 4。一个共同的机制是进化上保守的两个不同的细胞事件，一个驱动微管切断和其他涉及膜骨骼重组。
Katanin p60 (kp60), a microtubule-severing enzyme, plays a key role in cytoskeletal reorganization during various cellular events in an ATP-dependent manner. We show that a single domain isolated from the N terminus of mouse katanin p60 (kp60-NTD) binds to tubulin. The solution structure of kp60-NTD was determined by NMR. Although their sequence similarities were as low as 20%, the structure of kp60-NTD revealed a striking similarity to those of the microtubule interacting and trafficking (MIT) domains, which adopt anti-parallel three-stranded helix bundle. In particular, the arrangement of helices 2 and 3 is well conserved between kp60-NTD and the MIT domain from Vps4, which is a homologous protein that promotes disassembly of the endosomal sorting complexes required for transport III membrane skeleton complex. Mutation studies revealed that the positively charged surface formed by helices 2 and 3 binds tubulin. This binding mode resembles the interaction between the MIT domain of Vps4 and Vps2/CHMP1a, a component of endosomal sorting complexes required for transport III. Our results show that both the molecular architecture and the binding modes are conserved between two AAA-ATPases, kp60 and Vps4. A common mechanism is evolutionarily conserved between two distinct cellular events, one that drives microtubule severing and the other involving membrane skeletal reorganization.