The Polo-like kinase Plx1 interacts with and inhibits Myt1 after fertilization of Xenopus eggs
The Polo-like kinase Plx1 interacts with and inhibits Myt1 after fertilization of Xenopus eggs
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DOI：
10.1038/sj.emboj.7600567
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发表时间：
2005-03-09
期刊：
影响因子：
11.4
通讯作者：
Sagata, N
中科院分区：
文献类型：
--
作者：
Inoue, D;Sagata, N
在非洲爪蟾卵母细胞减数分裂细胞周期中，Mos-MAPK通路的下游激酶p90（rsk）与Cdc 2抑制性激酶Myt 1相互作用并抑制Cdc 2抑制性激酶Myt 1。然而，p90（rsk）在受精后由于Mos的降解而失活。在这里，我们表明，波罗样激酶Plx 1，而不是p90（rsk），相互作用，并抑制Myt 1非洲爪蟾卵受精后。在胚胎细胞周期的M期，Cdc 2磷酸化Thr 478上的Myt 1，从而为Plx 1创建对接位点。Plx 1在体内外均能磷酸化Myt 1并抑制其激酶活性。Myt 1和Plx 1之间的相互作用至少部分是正常胚胎细胞分裂所必需的。最后，有趣的是，Myt 1是磷酸化的Thr 478甚至在减数分裂细胞周期，但其与Plx 1的相互作用在很大程度上抑制了p90（rsk）介导的磷酸化。这些结果表明，Myt 1抑制机制在非洲爪蟾卵受精，并强烈建议Plx 1作为一个直接抑制激酶Myt 1在非洲爪蟾有丝分裂细胞周期。
During the meiotic cell cycle in Xenopus oocytes, p90(rsk), the downstream kinase of the Mos - MAPK pathway, interacts with and inhibits the Cdc2 inhibitory kinase Myt1. However, p90(rsk) is inactivated after fertilization due to the degradation of Mos. Here we show that the Polo- like kinase Plx1, instead of p90(rsk), interacts with and inhibits Myt1 after fertilization of Xenopus eggs. At the M phase of the embryonic cell cycle, Cdc2 phosphorylates Myt1 on Thr478 and thereby creates a docking site for Plx1. Plx1 can phosphorylate Myt1 and inhibit its kinase activity both in vitro and in vivo. The interaction between Myt1 and Plx1 is required, at least in part, for normal embryonic cell divisions. Finally, and interestingly, Myt1 is phosphorylated on Thr478 even during the meiotic cell cycle, but its interaction with Plx1 is largely inhibited by p90(rsk)-mediated phosphorylation. These results indicate a switchover in the Myt1 inhibition mechanism at fertilization of Xenopus eggs, and strongly suggest that Plx1 acts as a direct inhibitory kinase of Myt1 in the mitotic cell cycles in Xenopus.