Drosophila kinesin-8 stabilizes the kinetochore-microtubule interaction
Drosophila kinesin-8 stabilizes the kinetochore-microtubule interaction
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DOI：
10.1083/jcb.201807077
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发表时间：
2019-02-01
影响因子：
7.8
通讯作者：
Goshima, Gohta
中科院分区：
文献类型：
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作者：
Edzuka, Tomoya;Goshima, Gohta
驱动蛋白-8是多种动物和酵母细胞类型中正确的染色体比对所必需的。然而，目前还不清楚这种马达蛋白家族如何控制染色体排列，因为已经确定了多种生化活性，包括研究之间的不一致活性。在这里，我们发现，果蝇驱动蛋白-8（Klp 67 A）具有微管（MT）加上端稳定和不稳定的活动，除了驱动蛋白-8的通常观察到的MT加上端定向运动和微管蛋白结合活性在体外。我们进一步表明，Klp 67 A是所需的稳定kinetochore-MT附着在S2细胞的前中期。在Klp 67 A的情况下，异常长的MT以正常频率以“末端”方式与动粒相互作用。然而，这种互动是不稳定的，MT经常变得分离。这种表型是由MT加上末端稳定因子CLASP的异位表达拯救的，但不是由人工缩短MT。我们发现，人驱动蛋白-8（KIF 18 A）也是重要的，以确保适当的MT连接。总体而言，这些结果表明，MT稳定活性的驱动蛋白-8是至关重要的稳定kinetochore-MT连接。
Kinesin-8 is required for proper chromosome alignment in a variety of animal and yeast cell types. However, it is unclear how this motor protein family controls chromosome alignment, as multiple biochemical activities, including inconsistent ones between studies, have been identified. Here, we find that Drosophila kinesin-8 (Klp67A) possesses both microtubule (MT) plus end-stabilizing and -destabilizing activity, in addition to kinesin-8's commonly observed MT plus end-directed motility and tubulin-binding activity in vitro. We further show that Klp67A is required for stable kinetochore-MT attachment during prometaphase in S2 cells. In the absence of Klp67A, abnormally long MTs interact in an "end-on" fashion with kinetochores at normal frequency. However, the interaction is unstable, and MTs frequently become detached. This phenotype is rescued by ectopic expression of the MT plus end-stabilizing factor CLASP, but not by artificial shortening of MTs. We show that human kinesin-8 (KIF18A) is also important to ensure proper MT attachment. Overall, these results suggest that the MT-stabilizing activity of kinesin-8 is critical for stable kinetochore-MT attachment.