Purification and cloning of a protein kinase that phosphorylates and activates the polo-like kinase Plx1
Purification and cloning of a protein kinase that phosphorylates and activates the polo-like kinase Plx1
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DOI：
10.1126/science.282.5394.1701
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发表时间：
1998-11-27
期刊：
影响因子：
56.9
通讯作者：
Maller, JL
中科院分区：
文献类型：
--
作者：
Qian, YW;Erikson, E;Maller, JL
非洲爪蟾polo样激酶1（Plx 1）在有丝分裂过程中对于Cdc 25 C的激活、纺锤体组装和细胞周期蛋白B降解是必不可少的。来自各种生物体的Polo样激酶被一种未鉴定的蛋白激酶磷酸化而活化。一种蛋白激酶，polo样激酶激酶1或xPlkk1，磷酸化和激活Plx1在体外被纯化到接近同质和克隆。磷酸肽图谱的Plx1磷酸化在体外重组xPlkk1或孕酮处理的卵母细胞表明，xPlkk1可以激活Plx1在体内。的xPlkk1蛋白本身也被激活的丝氨酸和苏氨酸残基上的磷酸化，并在体内的xPlkk1的激活动力学密切相关的Plx1的激活。此外，xPlkk 1注射到非洲爪蟾卵母细胞中加速了Plx 1的激活和细胞周期从G（2）期到M期的转变。这些结果定义了一个蛋白激酶级联，调节有丝分裂的几个事件。
The Xenopus polo-like kinase 1 (Plx1) is essential during mitosis for the activation of Cdc25C, for spindle assembly, and for cyclin B degradation. Polo-Like kinases from various organisms are activated by phosphorylation by an unidentified protein kinase. A protein kinase, polo-like kinase kinase 1 or xPlkk1, that phosphorylates and activates Plx1 in vitro was purified to near homogeneity and cloned. Phosphopeptide mapping of Plx1 phosphorylated in vitro by recombinant xPlkk1 or in progesterone-treated oocytes indicates that xPlkk1 may activate Plx1 in vivo. The xPlkk1 protein itself was also activated by phosphorylation on serine and threonine residues, and the kinetics of activation of xPlkk1 in vivo closely paralleled the activation of Plx1. Moreover, microinjection of xPlkk1 into Xenopus oocytes accelerated the timing of activation of Plx1 and the transition from G(2) to M phase of the cell cycle. These results define a protein kinase cascade that regulates several events of mitosis.