Regulatory mechanisms of cytoskeletal proteins by phosphorylation and their cellular functions

我们发现，CDK1使Vimentin-Ser55从早中期到中期磷酸化，导致PLK-1向Vimentin募集。当Plk1与Vimentin的磷酸化丝氨酸55结合后，Plk1被激活，然后磷酸化Vimentin-Ser82。在细胞质分裂过程中，Rho-Kinase和Aurora-B在卵裂沟特异性地使IF磷酸化。CDK1、Plk1、Rho-Kinase和Aurora-B对IF的磷酸化在局部IF的分解中起着重要作用，并且对于IF网络有效地分离成子细胞是必不可少的。我们也是。发现CDK1使内着丝粒蛋白(LNCENP)上的Thr59和Thr388磷酸化。CDK1对INCENP的磷酸化是Plk1向着丝粒募集所必需的，而Plk1与Aurora-B在INCENP上的复合体的形成可能在染色体动力学的调节中起着关键作用。我们鉴定了Trichoplein和Fas结合因子-1(FBF-I)是新的角蛋白结合蛋白。Trichoplein和FBF-1有一个结构域，显示出Trichohyalin和plectin之间的序列相似性程度很低，被命名为Trichohyalin/plectin同源域(TPHD)。这些蛋白与角蛋白共定位，也定位于细胞与细胞间的黏附。

We found that Cdk1 phosphorylates vimentin-Ser55 from prometaphase to metaphase, leading to the recruitment of Plk-1 to vimentin. Upon binding to Phospho-Ser55 of vimentin, Plk1 is activated, and then phosphorylates vimentin-Ser82. During cytokinesis, Rho-kinase and Aurora-B specifically phosphorylate IFs at the cleavage furrow. The IF phosphorylation by Cdk1, Plk1, Rho-kinase, and Aurora-B plays an important role in the local IF breakdown, and is essential for the efficient segregation of IF networks into daughter cells. We also. found that Cdk1 phosphorylates Thr59 and Thr388 on inner centromere protein (lNCENP). INCENP phosphorylation by Cdk1 is necessary for the recruitment of Plk1 to the kinetochore, and the complex formation of Plk1 and Aurora-B on INCENP may play crucial roles in the regulation of chromosome dynamics. We identified Trichoplein and Fas binding factor-1 (Fbf-I) as novel keratin-binding proteins. Trichoplein and Fbf-1 have a domain that shows a low degree of sequence similarity between trichohyalin and plectin, designated, as trichohyalin/plectin homology domain (TPHD). These proteins co-localized with keratin, and also localized at cell-cell adhesion.