EFFECTS OF PHOSPHORYLATION BY CAK ON CYCLIN BINDING BY CDC2 AND CDK2
EFFECTS OF PHOSPHORYLATION BY CAK ON CYCLIN BINDING BY CDC2 AND CDK2
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DOI：
10.1128/mcb.15.1.345
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发表时间：
1995-01-01
影响因子：
5.3
通讯作者：
MORGAN, DO
中科院分区：
文献类型：
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作者：
DESAI, D;WESSLING, HC;MORGAN, DO
细胞周期蛋白依赖性蛋白激酶（CDK）通过与细胞周期蛋白的结合以及通过CDK激活激酶（CAK）在保守的苏氨酸残基处的磷酸化而被激活。我们已经研究了各种人CDK和细胞周期蛋白亚基在体外的结合，使用来自杆状病毒感染的昆虫细胞的纯化蛋白。我们发现大多数已知存在于人类细胞中的CDK-cyclin复合物（CDC 2-cyclin B，CDK 2-cyclin A和CDK 2-cyclin E）在没有磷酸化或其他细胞成分的情况下以高亲和力形式存在。一种复合物（CDC 2-细胞周期蛋白A）仅在活化苏氨酸残基处的CDC 2的CAK介导的磷酸化后以高亲和力形成。即使在CDC 2亚基磷酸化后，CDC 2在体外也不会以高亲和力与细胞周期蛋白E结合。因此，磷酸化在高亲和力CDK-细胞周期蛋白复合物的形成中具有不同的重要性。
The cyclin-dependent protein kinases (CDKs) are activated by association,vith cyclins and by phosphorylation at a conserved threonine residue by the CDK-activating kinase (CAK). We have studied the binding of various human CDK and cyclin subunits in vitro, using purified proteins derived from baculovirus-infected insect cells. We find that most CDK-cyclin complexes known tb exist in human cells (CDC2-cyclin B, CDK2-cyclin A, and CDK2-cyclin E) form with high affinity in the absence of phosphorylation or other cellular components. One complex (CDC2-cyclin A) forms with high affinity only after CAK-mediated phosphorylation of CDC2 at the activating threonine residue. CDC2 does not bind with high affinity to cyclin E in vitro, even after phosphorylation of the CDC2 subunit. Thus, phosphorylation is of varying importance in the formation of high-affinity CDK-cyclin complexes.