Axin localizes to the centrosome and is involved in microtubule nucleation
Axin localizes to the centrosome and is involved in microtubule nucleation
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DOI：
10.1038/embor.2009.45
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发表时间：
2009-06-01
期刊：
影响因子：
7.7
通讯作者：
Kikuchi, Akira
中科院分区：
文献类型：
--
作者：
Fumoto, Katsumi;Kadono, Moe;Kikuchi, Akira
已知轴蛋白在 Wnt 通路中 β-连环蛋白的降解中具有重要作用。在这里，我们揭示了 Axin 在中心体的新功能。轴蛋白定位于各种细胞系的中心体并与γ-微管蛋白形成复合物。诺考达唑治疗后，Axin 的敲低降低了 γ-微管蛋白和 γ-微管蛋白复合蛋白 2（γ-微管蛋白环复合物的成分）在中心体的定位以及中心体微管成核活性。这些表型不能通过降低β-连环蛋白水平来挽救。尽管 Axin 的表达可以在 Axin 敲低细胞中挽救这些表型，但与 Axin 高度同源的 Axin2 的过度表达却不能。 Axin2也定位于中心体，但它不与γ-微管蛋白形成复合物。这些结果表明，Axin（而非 Axin2）通过与中心体处的 γ-微管蛋白形成复合物来参与微管成核。
Axin is known to have an important role in the degradation of beta-catenin in the Wnt pathway. Here, we reveal a new function of Axin at the centrosome. Axin was localized to the centrosome in various cell lines and formed a complex with gamma-tubulin. Knockdown of Axin reduced the localization of gamma-tubulin and gamma-tubulin complex protein 2-components of the gamma-tubulin ring complex-to the centrosome and the centrosomal microtubule nucleation activity after treatment with nocodazole. These phenotypes could not be rescued by the reduction in the levels of beta-catenin. Although the expression of Axin rescued these phenotypes in Axin-knockdown cells, overexpression of Axin2, which is highly homologous to Axin, could not. Axin2 was also localized to the centrosome, but it did not form a complex with gamma-tubulin. These results suggest that Axin, but not Axin2, is involved in microtubule nucleation by forming a complex with gamma-tubulin at the centrosome.