Kinesin-8-specific loop-2 controls the dual activities of the motor domain according to tubulin protofilament shape.
Kinesin-8-specific loop-2 controls the dual activities of the motor domain according to tubulin protofilament shape.
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DOI：
10.1038/s41467-022-31794-3
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发表时间：
2022-07-20
影响因子：
16.6
通讯作者：
中科院分区：
文献类型：
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Kinesin-8s是一种具有双重活性的马达蛋白，可以在微管上进行运动并解聚微管正端，但它们结合这些不同活性的机制尚不清楚。我们通过在微管晶格和弯曲的微管末端模拟上获得白色念珠菌Kip3在不同催化状态下的低温EM结构(2.6-3.9 ä)来解决这一问题。我们还测定了微管非结合CaKip3-ADP(2.0 ä)的晶体结构，并分析了CaKip3和Kinesin-1突变体的生化活性。这些数据表明，Kinesin-8的微管解聚活性源于其运动核心的构象变化，这种构象变化通过其延伸的loop-2与微管蛋白之间的动态接触而被放大。在弯曲的微管末端，loop-1插入到前面的运动域中，形成头尾相连的kinesin-8阵列，补充loop-2与弯曲微管蛋白的接触，并帮助解聚。在微管晶格中的直管蛋白原丝上，环-2-微管蛋白接触抑制了运动核心的构象变化，但在ADP-PI状态下，这些接触是松弛的，允许颈部-连接件对接以进行运动。我们认为，这些微管形状引起的由环-2调节的促进微管解聚和促进运动的动蛋白状态之间的变化，是驱动蛋白-8马达双重活性的关键。Kinesin-8s是一种具有双重活性的马达蛋白，可以在微管上进行连续运动，并解聚微管加端。这项研究展示了Kinesin-8是如何通过它们的微管形状感应环-2区域在促进和促进微管解聚状态之间转换的。
Kinesin-8s are dual-activity motor proteins that can move processively on microtubules and depolymerize microtubule plus-ends, but their mechanism of combining these distinct activities remains unclear. We addressed this by obtaining cryo-EM structures (2.6–3.9 Å) of Candida albicans Kip3 in different catalytic states on the microtubule lattice and on a curved microtubule end mimic. We also determined a crystal structure of microtubule-unbound CaKip3-ADP (2.0 Å) and analyzed the biochemical activity of CaKip3 and kinesin-1 mutants. These data reveal that the microtubule depolymerization activity of kinesin-8 originates from conformational changes of its motor core that are amplified by dynamic contacts between its extended loop-2 and tubulin. On curved microtubule ends, loop-1 inserts into preceding motor domains, forming head-to-tail arrays of kinesin-8s that complement loop-2 contacts with curved tubulin and assist depolymerization. On straight tubulin protofilaments in the microtubule lattice, loop-2-tubulin contacts inhibit conformational changes in the motor core, but in the ADP-Pi state these contacts are relaxed, allowing neck-linker docking for motility. We propose that these tubulin shape-induced alternations between pro-microtubule-depolymerization and pro-motility kinesin states, regulated by loop-2, are the key to the dual activity of kinesin-8 motors. Kinesin-8s are dual-activity motor proteins that can move processively on microtubules and depolymerize microtubule plus-ends. This study shows how kinesin-8s alternate between a promotility and a pro-microtubule-depolymerization state via their tubulin shape-sensing loop-2 region.
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DOI：
10.1107/s0907444904019158
发表时间：
2004-12-01
影响因子：
2.2
作者：
Emsley, P;Cowtan, K
通讯作者：
Cowtan, K
影响因子：
5.6
作者：
Arora, Kritica;Talje, Lama;Kwok, Benjamin H.
通讯作者：
Kwok, Benjamin H.
影响因子：
--
作者：
Frazer, Corey;Joshi, Monika;Allingham, John S.
通讯作者：
Allingham, John S.
在核迁移方面，需要与酿酒酵母的动力学相关的KIP3。
影响因子：
7.8
作者：
DeZwaan, TM;Ellingson, E;Pellman, D;Roof, DM
通讯作者：
Roof, DM
影响因子：
16.6
作者：
Benoit MPMH;Asenjo AB;Paydar M;Dhakal S;Kwok BH;Sosa H
通讯作者：
Sosa H