Nek2 phosphorylates and stabilizes β-catenin at mitotic centrosomes downstream of Plk1.
Nek2 phosphorylates and stabilizes β-catenin at mitotic centrosomes downstream of Plk1.
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NEK2磷酸化并稳定β-catenin在PLK1下游的有丝分裂中心体上。
DOI：
10.1091/mbc.e13-06-0349
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发表时间：
2014-04
影响因子：
3.3
通讯作者：
Barth AI
中科院分区：
文献类型：
--
作者：
Mbom BC;Siemers KA;Ostrowski MA;Nelson WJ;Barth AI
Plk 1在稳定有丝分裂中心体的β-连环蛋白和促进中心体分离中调节Nek 2活性。Nek 2磷酸化β-连环蛋白中与GSK 3 β相同的调控位点（S33/S37/T41）以及其他位点，并抑制E3连接酶β-TrCP与β-连环蛋白的结合，从而阻止β-连环蛋白泛素化和降解。β-连环蛋白是一种多功能蛋白质，在细胞间粘附、Wnt信号传导和中心体周期中具有关键作用。尽管β-连环蛋白在细胞间粘附和Wnt信号传导中的调节已经很好地理解，但β-连环蛋白在中心体中是如何调节的还不清楚。NIMA相关蛋白激酶2（Nek 2）调节中心体分离/分裂，与β-连环蛋白结合并磷酸化。使用体外和基于细胞的测定，我们表明Nek 2磷酸化β-连环蛋白N-末端中与糖原合成酶激酶3β（GSK 3 β）相同的调节位点，其被特异性磷酸化-S33/S37/T41抗体识别，以及其他位点。Nek 2与β-连环蛋白的结合似乎抑制E3连接酶β-TrCP的结合并阻止β-连环蛋白泛素化和降解。因此，被Nek 2磷酸化的β-连环蛋白在有丝分裂中稳定并积累在中心体。我们进一步表明，polo样激酶1（Plk 1）调节Nek 2磷酸化和β-catenin的稳定。总之，这些结果确定了一种新的机制，调节β-连环蛋白的稳定性，是独立的GSK 3 β，并提供了新的见解，涉及Plk 1，Nek 2和β-连环蛋白，调节中心体周期的途径。
Plk1 regulates Nek2 activity in stabilizing β-catenin at mitotic centrosomes and in promoting centrosome separation. Nek2 phosphorylates the same regulatory sites (S33/S37/T41) as GSK3β in β-catenin, as well as additional sites, and inhibits binding of the E3 ligase β-TrCP to β-catenin, thereby preventing β-catenin ubiquitination and degradation. β-Catenin is a multifunctional protein with critical roles in cell–cell adhesion, Wnt signaling, and the centrosome cycle. Whereas the regulation of β-catenin in cell–cell adhesion and Wnt signaling are well understood, how β-catenin is regulated at the centrosome is not. NIMA-related protein kinase 2 (Nek2), which regulates centrosome disjunction/splitting, binds to and phosphorylates β-catenin. Using in vitro and cell-based assays, we show that Nek2 phosphorylates the same regulatory sites in the N-terminus of β-catenin as glycogen synthase kinase 3β (GSK3β), which are recognized by a specific phospho-S33/S37/T41 antibody, as well as additional sites. Nek2 binding to β-catenin appears to inhibit binding of the E3 ligase β-TrCP and prevents β-catenin ubiquitination and degradation. Thus β-catenin phosphorylated by Nek2 is stabilized and accumulates at centrosomes in mitosis. We further show that polo-like kinase 1 (Plk1) regulates Nek2 phosphorylation and stabilization of β-catenin. Taken together, these results identify a novel mechanism for regulating β-catenin stability that is independent of GSK3β and provide new insight into a pathway involving Plk1, Nek2, and β-catenin that regulates the centrosome cycle.