POLO-LIKE KINASE IS A CELL-CYCLE-REGULATED KINASE ACTIVATED DURING MITOSIS
POLO-LIKE KINASE IS A CELL-CYCLE-REGULATED KINASE ACTIVATED DURING MITOSIS
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DOI：
10.1074/jbc.270.36.21086
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发表时间：
1995-09-08
影响因子：
4.8
通讯作者：
FERRIS, DK
中科院分区：
文献类型：
--
作者：
HAMANAKA, R;SMITH, MR;FERRIS, DK
以前，我们证明了Polo样激酶（PLK）的表达是细胞DNA合成所必需的，并且PLK的过表达足以诱导DNA合成。我们现在报告，PLK的内源性水平，其磷酸化状态，和蛋白激酶活性在细胞周期进程中受到严格调控。PLK蛋白在G（1）中含量低，在S和G（2）M期间积累，并在有丝分裂后迅速减少。在有丝分裂期间，PLK在丝氨酸上磷酸化，并且其丝氨酸苏氨酸激酶功能在接近p34（cdc 2）的时间被激活。PLK的磷酸化形式在SDS-聚丙烯酰胺凝胶电泳上以降低的迁移率迁移，并且通过纯化的蛋白磷酸酶2A的去磷酸化将其转化为更快速迁移的形式并降低PLK激酶活性的总量。纯化的p34（cdc 2）-cyclin B复合物在体外可使PLK蛋白磷酸化，但对PLK激酶活性无明显影响。
Previously, we demonstrated that expression of polo-like kinase (PLK) is required for cellular DNA synthesis and that overexpression of PLK is sufficient to induce DNA synthesis. We now report that the endogenous levels of PLK, its phosphorylation status, and protein kinase activity are tightly regulated during cell cycle progression. PLK protein is low in G(1), accumulates during S and G(2)M, and is rapidly reduced after mitosis. During mitosis, PLK is phosphorylated on serine, and its serine threonine kinase function is activated at a time close to that of p34(cdc2). The phosphorylated form of PLK migrates with reduced mobility on SDS-polyacrylamide gel electrophoresis, and dephosphorylation by purified protein phosphatase 2A converts it to the more rapidly migrating form and reduces the total amount of PLK kinase activity. Purified p34(cdc2)-cyclin B complex can phosphorylate PLK protein in vitro but causes little increase in PLK kinase activity.