Regulation of Drosophila Ca2+/calmodulin-dependent protein kinase II by autophosphorylation analyzed by site-directed mutagenesis.
Regulation of Drosophila Ca2+/calmodulin-dependent protein kinase II by autophosphorylation analyzed by site-directed mutagenesis.
复制标题
通过定点诱变分析自磷酸化对果蝇 Ca2/钙调蛋白依赖性蛋白激酶 II 的调节。
DOI：
10.1046/j.1471-4159.1998.71010378.x
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发表时间：
1998
影响因子：
4.7
通讯作者：
Griffith,LC
中科院分区：
文献类型：
--
作者：
Wang,Z;Palmer,G;Griffith,LC
在这项研究中，我们证明了果蝇钙/钙调素依赖性蛋白激酶II（CaMK II）能够通过其调节域内三种苏氨酸的自磷酸化进行复杂的调节。具体来说，我们表明果蝇CaMKII中苏氨酸-287的自磷酸化与大鼠α CaMKII中苏氨酸-286的磷酸化相当，无论是在赋予酶钙独立性的能力方面，还是在其如何磷酸化的机制细节方面。该残基的自磷酸化仅发生在全酶结构内，并且需要钙调蛋白（CaM）与底物亚基结合。在果蝇激酶的CaM结合结构域中，苏氨酸-306和苏氨酸-307的磷酸化仅在缺乏CaM的情况下发生，并且这种磷酸化能够抑制进一步的CaM结合。此外，我们的研究结果表明，苏氨酸-306和苏氨酸-307的磷酸化不能模拟结合的CaM，以减轻CaM与分子间苏氨酸-287磷酸化的底物亚基结合的需要。这些结果表明，这种激酶的调节性自磷酸化的机制早于无脊椎动物和脊椎动物之间的分裂。
In this study we demonstrate thatDrosophilacalcium/calmodulin‐dependent protein kinase II (CaMKII) is capable of complex regulation by autophosphorylation of the three threonines within its regulatory domain. Specifically, we show that autophosphorylation of threonine‐287 inDrosophilaCaMKII is equivalent to phosphorylation of threonine‐286 in rat α CaMKII both in its ability to confer calcium independence on the enzyme and in the mechanistic details of how it becomes phosphorylated. Autophosphorylation of this residue occurs only within the holoenzyme structure and requires calmodulin (CaM) to be bound to the substrate subunit. Phosphorylation of threonine‐306 and threonine‐307 in the CaM binding domain of theDrosophilakinase occurs only in the absence of CaM, and this phosphorylation is capable of inhibiting further CaM binding. Additionally, our findings suggest that phosphorylation of threonine‐306 and threonine‐307 does not mimic bound CaM to alleviate the requirement for CaM binding to the substrate subunit for intermolecular threonine‐287 phosphorylation. These results demonstrate that the mechanism of regulatory autophosphorylation of this kinase predates the split between invertebrates and vertebrates.