Phosphorylation of Bcl-2 protein by CDC2 kinase during G2/M phases and its role in cell cycle regulation
Phosphorylation of Bcl-2 protein by CDC2 kinase during G2/M phases and its role in cell cycle regulation
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DOI：
10.1074/jbc.m906893199
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发表时间：
2000-07-14
影响因子：
4.8
通讯作者：
Matsuda, M
中科院分区：
文献类型：
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作者：
Furukawa, Y;Iwase, S;Matsuda, M
尽管有报道称Bcl-2磷酸化与某些类型的细胞凋亡有关，但对其功能意义和磷酸化的激酶仍有很多争议。在这项研究中，我们检测了Bcl-2是否被CDC2激酶磷酸化，CDC2激酶是真核细胞周期中G(2)/M转化的主要调节因子。当冈田酸激活HL-60细胞的CDC2时，Bcl-2很容易被磷酸化。磷酸化与G(2)/M期细胞的积累相关，但与凋亡水平不成正比。此外，我们发现Bcl-2在正常细胞周期的G(2)/M期被磷酸化。CDC2磷酸化Bcl-2的能力通过高纯度CDC2-cyclin B复合物的体外激酶试验得到证实。通过合成多肽和突变细胞系，我们确定了苏氨酸56 （Bcl-2序列中CDC2的两个共识位点之一）是被CDC2磷酸化的残基。苏氨酸56突变消除了Bcl-2的细胞周期抑制作用，但不影响抗凋亡功能。这些结果表明，Bcl-2的两种不同功能（抗凋亡和细胞周期抑制）受到磷酸化等翻译后机制的不同调节。cdc2介导的Bcl-2磷酸化可能在有丝分裂过程中的负调控事件中发挥一定的生理作用。
Although it has been reported that Bcl-2 phosphorylation is associated with certain types of apoptosis, there is much controversy over the functional significance of and the kinases responsible for the phosphorylation. In this study, we examined whether Bcl-2 is phosphorylated by CDC2 kinase, a master regulator of G(2)/M transition in the eukaryotic cell cycle. When CDC2 was activated by okadaic acid in HL-60 cells, Bcl-2 phosphorylation was readily induced. The phosphorylation was correlated with the accumulation of cells in G(2)/M phases, but was not proportional to the level of apoptosis. Furthermore, we found that Bcl-2 was phosphorylated during G(2)/M phases of normal cell cycle. The ability of CDC2 to phosphorylate Bcl-2 was confirmed by in vitro kinase assay with a highly purified CDC2-cyclin B complex. Using synthetic peptides and mutant cell lines, we identified threonine 56, one of two consensus sites for CDC2 within the Bcl-2 sequence, as a residue phosphorylated by CDC2. Mutation at threonine 56 abrogated the cell cycle inhibitory effect of Bcl-2 without affecting anti-apoptotic function. These results suggest that two distinct functions of Bcl-2 (anti-apoptosis and cell cycle inhibition) are differentially regulated by post-translational mechanisms such as phosphorylation. CDC2-mediated phosphorylation of Bcl-2 may play some physiological roles in the negative regulatory events during mitosis.