In vitro reconstitution of a CaMKII memory switch by an NMDA receptor-derived peptide.
In vitro reconstitution of a CaMKII memory switch by an NMDA receptor-derived peptide.
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DOI：
10.1016/j.bpj.2014.01.026
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发表时间：
2014-03
影响因子：
3.4
通讯作者：
H. Urakubo;Miharu Sato;Shin Ishii;Shinya Kuroda
中科院分区：
文献类型：
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作者：
H. Urakubo;Miharu Sato;Shin Ishii;Shinya Kuroda
Ca2+/钙调蛋白依赖性蛋白激酶 II (CaMKII) 已被证明在通过复杂的分子相互作用（包括多个突触靶点的磷酸化）建立记忆方面发挥着重要作用。然而，由于缺乏直接证据，CaMKII本身是否作为分子记忆仍存在争议。在这里，我们证明 CaMKII 的单个全酶本身可以充当可擦除的分子记忆开关。我们在体外在蛋白磷酸酶 1 存在的情况下重建了 Ca2+/钙调蛋白依赖性 CaMKII 自磷酸化，并发现 CaMKII 磷酸化仅在 N-甲基-D-天冬氨酸受体衍生肽存在时才显示出具有历史依赖性（滞后）的开关样反应。这种滞后现象是 Ca2+ 和蛋白磷酸酶 1 浓度依赖性的，表明 CaMKII 记忆开关不仅仅是由处于活性构象的 CaMKII 的 N-甲基-D-天冬氨酸受体衍生的肽锁引起的。肽磷酸化位点的突变改变了 Ca2+ 滞后范围。这些功能可能对于海马突触长期突触可塑性的诱导和维持至关重要。
Ca2+/Calmodulin-dependent protein kinase II (CaMKII) has been shown to play a major role in establishing memories through complex molecular interactions including phosphorylation of multiple synaptic targets. However, it is still controversial whether CaMKII itself serves as a molecular memory because of a lack of direct evidence. Here, we show that a single holoenzyme of CaMKII per se serves as an erasable molecular memory switch. We reconstituted Ca2+/Calmodulin-dependent CaMKII autophosphorylation in the presence of protein phosphatase 1 in vitro, and found that CaMKII phosphorylation shows a switch-like response with history dependence (hysteresis) only in the presence of anN-methyl-D-aspartate receptor-derived peptide. This hysteresis is Ca2+and protein phosphatase 1 concentration-dependent, indicating that the CaMKII memory switch is not simply caused by anN-methyl-D-aspartate receptor-derived peptide lock of CaMKII in an active conformation. Mutation of a phosphorylation site of the peptide shifted the Ca2+range of hysteresis. These functions may be crucial for induction and maintenance of long-term synaptic plasticity at hippocampal synapses.