Breakage of the oligomeric CaMKII hub by the regulatory segment of the kinase.
Breakage of the oligomeric CaMKII hub by the regulatory segment of the kinase.
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DOI：
10.7554/elife.57784
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发表时间：
2020-09-09
期刊：
影响因子：
7.7
通讯作者：
Kuriyan J
中科院分区：
文献类型：
--
作者：
Karandur D;Bhattacharyya M;Xia Z;Lee YK;Muratcioglu S;McAffee D;McSpadden ED;Qiu B;Groves JT;Williams ER;Kuriyan J
Ca 2 +/钙调蛋白依赖性蛋白激酶II（CaMKII）是一种寡聚酶，在神经元信号传导和心脏功能中发挥重要作用。先前，我们表明CaMKII的活化触发全酶之间的亚基交换，潜在地增加活性状态的扩散（Stratton等人，2014; Bhattacharyya等人，2016年）。使用质谱，我们现在显示，来自CaMKII-α调节片段的未磷酸化和磷酸化肽与CaMKII-α枢纽结合，并将其分解为较小的寡聚体。分子动力学模拟表明，调节段停靠在枢纽亚基之间的界面自发，捕获枢纽结构的大波动。哺乳动物细胞中表达的CaMKII-α的单分子荧光强度分析表明，CaMKII-α的激活导致全酶的不稳定。我们的研究结果表明，通过激活和磷酸化释放的调节片段允许它破坏枢纽，产生更小的组件，可能重新组装形成新的全酶。
Ca2+/calmodulin-dependent protein kinase II (CaMKII) is an oligomeric enzyme with crucial roles in neuronal signaling and cardiac function. Previously, we showed that activation of CaMKII triggers the exchange of subunits between holoenzymes, potentially increasing the spread of the active state (Stratton et al., 2014; Bhattacharyya et al., 2016). Using mass spectrometry, we show now that unphosphorylated and phosphorylated peptides derived from the CaMKII-α regulatory segment bind to the CaMKII-α hub and break it into smaller oligomers. Molecular dynamics simulations show that the regulatory segments dock spontaneously at the interface between hub subunits, trapping large fluctuations in hub structure. Single-molecule fluorescence intensity analysis of CaMKII-α expressed in mammalian cells shows that activation of CaMKII-α results in the destabilization of the holoenzyme. Our results suggest that release of the regulatory segment by activation and phosphorylation allows it to destabilize the hub, producing smaller assemblies that might reassemble to form new holoenzymes.