A role for protein kinase CK2 in cell proliferation:: evidence using a kinase-inactive mutant of CK2 catalytic subunit α
A role for protein kinase CK2 in cell proliferation:: evidence using a kinase-inactive mutant of CK2 catalytic subunit α
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DOI：
10.1038/sj.onc.1204307
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发表时间：
2001-04-12
期刊：
影响因子：
8
通讯作者：
Bianchini, L
中科院分区：
文献类型：
--
作者：
Lebrin, F;Chambaz, EM;Bianchini, L
蛋白激酶CK 2是一种普遍存在的、多效性的Ser/Thr蛋白激酶，由两个催化蛋白激酶组成。（α和/或α ′）和两个调节（B）亚基通常结合形成α（2）β（2）、α α ′ β（2）或α ′（2）β（2）异源四聚体。在两种成纤维细胞系：NIH 3 T3和CCL 39中进行分离的CK 2亚基α、α ′或β的过表达。为了干扰CK 2细胞功能，还用CK 2 α催化亚基的激酶失活突变体：CK 2 α-K68 A转染细胞。在NIH 3 T3细胞中，野生型亚基的过度表达（α、α '或β）对细胞增殖没有影响。相反，CK 2 α激酶缺陷突变体的过表达诱导细胞增殖的显著抑制，这是由于G1/如在NIH 3 T3和CCL 39细胞中使用BrdU掺入测量的瞬时转染实验中以及在CCL 39细胞中使用BrdU掺入测量的瞬时转染实验中所示的S进展。通过生长曲线分析稳定过表达CK 2 α-K68 A突变体的克隆。我们证明，激酶阴性突变体有能力整合内源性CK 2亚基池作为一个孤立的激酶无活性的α亚基和相关的β亚基在激酶无活性的四聚体。最后，我们发现，激酶失活突变体的表达干扰内源性CK 2底物的磷酸化，我们推测，最佳的磷酸化的目标蛋白CK 2是需要实现最佳的细胞周期进程。
Protein kinase CK2 is an ubiquitous and pleiotropic Ser/Thr protein kinase composed of two catalytic (alpha and/or alpha') and two regulatory (B) subunits generally combined to form alpha (2)beta (2), alpha alpha'beta (2), or alpha'(2)beta (2) heterotetramers, To gain more insight into the role of CK2 in the control of proliferation in mammalian cells, overexpression of isolated CK2 subunits alpha, alpha', or beta was carried out in two fibroblast cell lines: NIH3T3 and CCL39, To interfere with CK2 cellular functions, cells were also transfected with a kinase-inactive mutant of CK2 alpha catalytic subunit: CK2 alpha -K68A. In NIH3T3 cells, overexpression of either wild-type subunit (alpha, alpha' or beta) had no effect on cell proliferation, In contrast, overexpression of the CK2 alpha kinase-deficient mutant induced a marked inhibition of cell proliferation, This resulted from a defect in G1/S progression as demonstrated in transient transfection experiments in both NIH3T3 and CCL39 cells using BrdU incorporation measurements and in CCL39 clones stably overexpressing the CK2 alpha -K68A mutant by growth curve analysis. We demonstrated that the kinase-negative mutant has the capacity to integrate the endogenous CK2 subunit pool both as an isolated kinase-inactive alpha subunit and as associated to the beta subunit in a kinase-inactive tetramer. Finally we showed that expression of the kinase-inactive mutant interferes with phosphorylation of an endogenous CK2 substrate; we speculate that optimal phosphorylation of target proteins by CK2 is required to achieve optimal cell cycle progression.