Blangy A, Lane H A, d'Hérin P, Harper M, Kress M, Nigg E A
Swiss Institute for Experimental Cancer Research, Epalinges, Switzerland.
Cell. 1995 Dec 29;83(7):1159-69. doi: 10.1016/0092-8674(95)90142-6.
We have isolated a human homolog of Xenopus Eg5, a kinesin-related motor protein implicated in the assembly and dynamics of the mitotic spindle. We report that microinjection of antibodies against human Eg5 (HsEg5) blocks centrosome migration and causes HeLa cells to arrest in mitosis with monoastral microtubule arrays. Furthermore, an evolutionarily conserved cdc2 phosphorylation site (Thr-927) in HsEg5 is phosphorylated specifically during mitosis in HeLa cells and by p34cdc2/cyclin B in vitro. Mutation of Thr-927 to nonphosphorylatable residues prevents HsEg5 from binding to centrosomes, indicating that phosphorylation controls the association of this motor with the spindle apparatus. These results indicate that HsEg5 is required for establishing a bipolar spindle and that p34cdc2 protein kinase directly regulates its localization.
我们分离出了非洲爪蟾Eg5的一种人类同源物，这是一种与驱动蛋白相关的运动蛋白，参与有丝分裂纺锤体的组装和动态变化。我们报道，显微注射抗人类Eg5（HsEg5）抗体可阻断中心体迁移，并使HeLa细胞停滞在有丝分裂期，形成单星体微管阵列。此外，HsEg5中一个进化上保守的cdc2磷酸化位点（苏氨酸-927）在HeLa细胞有丝分裂期间被特异性磷酸化，并且在体外被p34cdc2/细胞周期蛋白B磷酸化。将苏氨酸-927突变为不可磷酸化的残基会阻止HsEg5与中心体结合，这表明磷酸化控制了这种运动蛋白与纺锤体装置的结合。这些结果表明，HsEg5是建立双极纺锤体所必需的，并且p34cdc2蛋白激酶直接调节其定位。
