The Drosophila orthologue of xPlkk1 is not essential for Polo activation and is necessary for proper contractile ring formation
The Drosophila orthologue of xPlkk1 is not essential for Polo activation and is necessary for proper contractile ring formation
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DOI：
10.1016/j.yexcr.2005.10.033
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发表时间：
2006-02-01
影响因子：
3.7
通讯作者：
Tavares, AA
中科院分区：
文献类型：
--
作者：
Alves, PS;Godinho, SA;Tavares, AA
Polo样激酶（Plks）对于有丝分裂的进展是必需的。这些激酶的活性在M期达到峰值，这种激活归因于磷酸化。能够在体外激活Plks的激酶先前已经在哺乳动物细胞和非洲爪蟾卵母细胞中鉴定出（分别为SLK和xPIKK 1），尽管在体内相关性尚未明确建立。为了研究波罗酶活性的调节，我们鉴定并克隆了一个属于ste 20 ser/thr家族的果蝇激酶，该激酶与xPIKKI和SLK具有密切的序列同源性。我们将这种激酶命名为dPIKK，并表明dPIKK在体外与波罗结合并磷酸化，导致后者的激活。另一方面，当从S2细胞中去除dPIKK时，波罗的激活似乎没有受到损害，这表明其他激酶在体内调节波罗的活性。此外，我们发现，一个百分比的dPlkk耗尽的细胞未能形成一个适当的肌动蛋白环在有丝分裂结束时，导致分裂沟的组装失败，并形成双核细胞。后期收缩环中检测到的dPikk积累加强了这种激酶在胞质分裂中起作用的想法，（c）2005 Elsevier Inc. All rights reserved.
Polo-like kinases (Plks) are essential for progression through mitosis. The activity of these kinases peak during M phase and this activation has been attributed to phosphorylation. Kinases capable of activating Plks in vitro have been previously identified both in mammalian cells and in Xenopus laevis oocytes (SLK and xPIkk1, respectively), although in in vivo correlation has, not been clearly established. In order to study the regulation of Polo activity, we identified and cloned a Drosophila melanogaster kinase belonging to the ste20 ser/thr family that presents a close sequence homology with xPIkkI and SLK. We termed this kinase dPIkk and showed that dPlkk associates with and phosphorylates Polo in vitro, resulting in the activation of the latter, On the other hand, when dPIkk is depleted from S2 cells, Polo activation does not seem to be impaired, suggesting that other kinases are imolved in regulating Polo activity in vivo. Additionally, we found that a percentage of dPlkk-depleted cells fail to form a proper actin ring at the end of mitosis, leading to a failure in the assembly of the cleavage furrow and to the formation of binucleated cells. The detected accumulation of dPikk in the contractile ring late in anaphase reinforces the idea that this kinase plays a role in cytokinesis, (c) 2005 Elsevier Inc. All rights reserved.