GSK-3β regulates proper mitotic spindle formation in cooperation with a component of the γ-tubulin ring complex, GCP5
GSK-3β regulates proper mitotic spindle formation in cooperation with a component of the γ-tubulin ring complex, GCP5
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DOI：
10.1074/jbc.m710282200
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发表时间：
2008-05-09
影响因子：
4.8
通讯作者：
Kikuchi, Akira
中科院分区：
文献类型：
--
作者：
Izumi, Nanae;Fumoto, Katsumi;Kikuchi, Akira
已知糖原合成酶激酶-3 β（GSK-3 β）在细胞中微管网络的动力学调节中起作用。在这里，我们显示GSK-3 β在有丝分裂纺锤体的正确形成中的作用，通过与GCP 5的相互作用，GCP 5是γ-微管蛋白环复合物（γ TuRC）的一个组成部分。在体外，GCP 5直接与GSK-3 β结合，并且在内源性水平的完整细胞中也观察到它们的相互作用。GCP 5的消耗显著降低了GCP 2和γ-微管蛋白在γ TuRC级分的蔗糖密度梯度和破坏γ-微管蛋白定位到纺锤体极中的有丝分裂细胞。GCP 5似乎是γ TuRC的形成或稳定以及γ-微管蛋白向纺锤体极的募集所需的。AGSK-3抑制剂不仅导致γ-微管蛋白和GCP 5在纺锤体极的积累，而且还增强了纺锤体极微管成核活性。GCP 5的耗尽挽救了在用GSK-3抑制剂处理的细胞中观察到的纺锤体极的这种破坏的组织。此外，GSK-3的抑制增强了γ TuRC与从体外有丝分裂细胞分离的中心体的结合。我们的研究结果表明，GSK-3 β调节γ TuRC，包括GCP 5，纺锤体极的本地化，从而控制适当的有丝分裂纺锤体的形成。
Glycogen synthase kinase-3 beta (GSK-3 beta) is known to play a role in the regulation of the dynamics of microtubule networks in cells. Here we show the role of GSK-3 beta in the proper formation of the mitotic spindles through an interaction with GCP5, a component of the gamma-tubulin ring complex (gamma TuRC). GCP5 bound directly to GSK-3 beta in vitro, and their interaction was also observed in intact cells at endogenous levels. Depletion of GCP5 dramatically reduced the GCP2 and gamma-tubulin in the gamma TuRC fraction of sucrose density gradients and disrupted gamma-tubulin localization to the spindle poles in mitotic cells. GCP5 appears to be required for the formation or stability of gamma TuRC and the recruitment of gamma-tubulin to the spindle poles. AGSK-3 inhibitor not only led to the accumulation of gamma-tubulin and GCP5 at the spindle poles but also enhanced microtubule nucleation activity at the spindle poles. Depletion of GCP5 rescued this disrupted organization of spindle poles observed in cells treated with the GSK-3 inhibitor. Furthermore, the inhibition of GSK-3 enhanced the binding of gamma TuRC to the centrosome isolated from mitotic cells in vitro. Our findings suggest that GSK-3 beta regulates the localization of gamma TuRC, including GCP5, to the spindle poles, thereby controlling the formation of proper mitotic spindles.