The Eyes Absent proteins (EYA1-4) are a biochemically unique group of tyrosine phosphatases known to be tumour-promoting across a range of cancer types. To date, the targets of EYA phosphatase activity remain largely uncharacterised. Here, we identify Polo-like kinase 1 (PLK1) as an interactor and phosphatase substrate of EYA4 and EYA1, with pY445 on PLK1 being the primary target site. Dephosphorylation of pY445 in the G2 phase of the cell cycle is required for centrosome maturation, PLK1 localization to centrosomes, and polo-box domain (PBD) dependent interactions between PLK1 and PLK1-activation complexes. Molecular dynamics simulations support the rationale that pY445 confers a structural impairment to PBD-substrate interactions that is relieved by EYA-mediated dephosphorylation. Depletion of EYA4 or EYA1, or chemical inhibition of EYA phosphatase activity, dramatically reduces PLK1 activation, causing mitotic defects and cell death. Overall, we have characterized a phosphotyrosine signalling network governing PLK1 and mitosis.

眼睛缺失蛋白 (EYA1-4) 是一组生物化学上独特的酪氨酸磷酸酶，已知可促进多种癌症类型的肿瘤生长。迄今为止，EYA 磷酸酶活性的目标在很大程度上仍然未知。在这里，我们将 Polo 样激酶 1 (PLK1) 确定为 EYA4 和 EYA1 的相互作用子和磷酸酶底物，其中 PLK1 上的 pY445 是主要靶位点。 pY445 在细胞周期 G2 期的去磷酸化对于中心体成熟、PLK1 定位到中心体以及 PLK1 和 PLK1 激活复合物之间的 polo-box 结构域 (PBD) 依赖性相互作用是必需的。分子动力学模拟支持这样的基本原理：pY445 会对 PBD-底物相互作用造成结构损伤，而 EYA 介导的去磷酸化可以缓解这种结构损伤。 EYA4 或 EYA1 的耗竭，或 EYA 磷酸酶活性的化学抑制，会显着降低 PLK1 的激活，导致有丝分裂缺陷和细胞死亡。总体而言，我们已经表征了控制 PLK1 和有丝分裂的磷酸酪氨酸信号网络。