Wang Weiyi, Cantos-Fernandes Soraya, Lv Yuncong, Kuerban Hureshitanmu, Ahmad Shoeb, Wang Chunguang, Gigant Benoît
Department of Central Laboratory, Shanghai Tenth People's Hospital of Tongji University, School of Life Sciences and Technology, Tongji University, Shanghai, 200092, China.
Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette cedex, France.
Nat Commun. 2017 Jul 10;8(1):70. doi: 10.1038/s41467-017-00091-9.
Kinesin-13s are critical microtubule regulators which induce microtubule disassembly in an ATP dependent manner. To clarify their mechanism, we report here the crystal structure of a functional construct of the kinesin-13 Kif2C/MCAK in an ATP-like state and bound to the αβ-tubulin heterodimer, a complex mimicking the species that dissociates from microtubule ends during catalytic disassembly. Our results picture how Kif2C stabilizes a curved tubulin conformation. The Kif2C α4-L12-α5 region undergoes a remarkable 25° rotation upon tubulin binding to target the αβ-tubulin hinge. This movement leads the β5a-β5b motif to interact with the distal end of β-tubulin, whereas the neck and the KVD motif, two specific elements of kinesin-13s, target the α-tubulin distal end. Taken together with the study of Kif2C mutants, our data suggest that stabilization of a curved tubulin is an important contribution to the Kif2C mechanism.Kinesin-13s are microtubule depolymerizing enzymes. Here the authors present the crystal structure of a DARPin fused construct comprising the short neck region and motor domain of kinesin-13 in complex with an αβ-tubulin heterodimer, which shows that kinesin-13 functions by stabilizing a curved tubulin conformation.
驱动蛋白-13是关键的微管调节因子，它以ATP依赖的方式诱导微管解聚。为了阐明其作用机制，我们在此报告了处于ATP样状态且与αβ-微管蛋白异二聚体结合的驱动蛋白-13 Kif2C/MCAK功能构建体的晶体结构，该复合物模拟了在催化解聚过程中从微管末端解离的物质。我们的结果展示了Kif2C如何稳定弯曲的微管蛋白构象。在与微管蛋白结合时，Kif2C的α4-L12-α5区域会发生显著的25°旋转，以靶向αβ-微管蛋白铰链。这一运动导致β5a-β5b基序与β-微管蛋白的远端相互作用，而颈部和KVD基序这两个驱动蛋白-13的特定元件则靶向α-微管蛋白的远端。结合对Kif2C突变体的研究，我们的数据表明稳定弯曲的微管蛋白是Kif2C作用机制的一个重要贡献。驱动蛋白-13是微管解聚酶。在此，作者展示了一种包含驱动蛋白-13短颈部区域和运动结构域的DARPin融合构建体与αβ-微管蛋白异二聚体复合物的晶体结构，这表明驱动蛋白-13通过稳定弯曲的微管蛋白构象发挥作用。
