The oncogenic serine/threonine kinase Pim-1 phosphorylates and inhibits the activity of Cdc25C-associated kinase 1 (C-TAK1) -: A novel role for Pim-1 at the G2/M cell cycle checkpoint
The oncogenic serine/threonine kinase Pim-1 phosphorylates and inhibits the activity of Cdc25C-associated kinase 1 (C-TAK1) -: A novel role for Pim-1 at the G2/M cell cycle checkpoint
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DOI：
10.1074/jbc.m404440200
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发表时间：
2004-11-12
影响因子：
4.8
通讯作者：
Möröy, T
中科院分区：
文献类型：
--
作者：
Bachmann, M;Hennemann, H;Möröy, T
Pim-1癌基因编码一种丝氨酸-苏氨酸激酶，它传递来自细胞因子受体的信号，当高水平表达时，有助于淋巴样肿瘤的形成。在这里，我们证明了蛋白激酶CDC25 C相关蛋白激酶1(C-TAK1)是PIM-1的结合伙伴和底物。Pim-1和C-TAK1在生物化学和酵母双杂交实验中表现出物理相互作用。免疫荧光实验表明，Pim-1.C-TAK1复合体以胞质为主。瞬时转染Pim-1后，Pim-1也出现在细胞核内，并能将C-TAK1募集到胞核内。Pim-1和C-TAK1都发生了自身磷酸化，但只有Pim-1能够磷酸化C-TAK1，反之亦然。C-TAK1的质谱学分析表明，自磷酸化和Pim-1介导的磷酸化的位点是不同的，不重叠。Pim-1的磷酸化显著降低了C-TAK1的活性，特别是它对CDC25C的磷酸化和失活能力，CDC25C是一种积极促进细胞周期G(2)/M期进展的蛋白。因此，我们的发现直接表明Pim-1在细胞周期的G(2)/M转换中作为一个正向调节因子的新角色。
The Pim-1 oncogene encodes a serine-threonine kinase that relays signals from cytokine receptors and contributes to the formation of lymphoid tumors when expressed at high levels. Here we show that the protein kinase Cdc25 C-associated kinase 1 (C-TAK1) is a binding partner and a substrate of Pim-1. A physical interaction of Pim-1 and C-TAK1 could be shown biochemically and in yeast two-hybrid assays. Immunofluorescence experiments suggested that Pim-1.C-TAK1 complexes are predominantly cytoplasmic. When transiently transfected, Pim-1 was also found in the nucleus and could recruit C-TAK1 to this compartment. Both Pim-1 and C-TAK1 underwent autophosphorylation, but only Pim-1 was able to phosphorylate C-TAK1 but not vice versa. Mass spectrometry analysis of C-TAK1 suggested that the sites of autophosphorylation and Pim-1-mediated phosphorylation are distinct and not overlapping. Phosphorylation by Pim-1 decreased C-TAK1 kinase activity significantly, in particular its ability to phosphorylate and inactivate Cdc25C, a protein that actively promotes cell cycle progression at the G(2)/M phase. Hence our findings directly suggest a novel role for Pim-1 as a positive regulator at the G(2)/M transition of the cell cycle.