Differential CaMKII regulation by voltage-gated calcium channels in the striatum.
Differential CaMKII regulation by voltage-gated calcium channels in the striatum.
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DOI：
10.1016/j.mcn.2015.08.003
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发表时间：
2015-09
期刊：
影响因子：
--
通讯作者：
Colbran RJ
中科院分区：
文献类型：
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作者：
Pasek JG;Wang X;Colbran RJ
钙信号传导调节纹状体中型多棘神经元的突触可塑性和许多其他功能，从而调节基底神经节功能。 Ca2+/钙调蛋白依赖性蛋白激酶 II (CaMKII) 是一种主要的钙依赖性信号蛋白，可将钙进入与多种细胞变化结合起来。 CaMKII 激活导致 Thr286 处的自磷酸化，并在钙信号消散后维持不依赖于钙的 CaMKII 活性。然而，人们对纹状体 CaMKII 的调节机制知之甚少。为了解决这个问题，用钙通道药理学调节剂处理小鼠脑切片，并对背侧纹状体的冲孔进行免疫印迹以检测 CaMKII Thr286 自磷酸化，作为 CaMKII 激活的指标。 KCl 去极化使 CaMKII 自磷酸化水平增加约 2 倍；这种增加被 LTCC 拮抗剂阻断，并通过药物 LTCC 激活剂治疗来模拟。细胞外钙的螯合除了降低 NMDA 受体 GluN2B 亚基和 AMPA 受体 GluA1 亚基中 CaMKII 位点的磷酸化外，还可以在 5 分钟内显着降低基础 CaMKII 自磷酸化，并增加胞浆部分中总 CaMKII 的水平。我们还发现，CaMKII 自磷酸化基础水平的维持需要低压门控 T 型钙通道，但不需要 LTCC 或 R 型钙通道。我们的研究结果表明，CaMKII 活性受到纹状体中多个钙通道的动态调节，从而将钙进入与关键下游底物耦合。
Calcium signaling regulates synaptic plasticity and many other functions in striatal medium spiny neurons to modulate basal ganglia function. Ca2+/calmodulin-dependent protein kinase II (CaMKII) is a major calcium-dependent signaling protein that couples calcium entry to diverse cellular changes. CaMKII activation results in autophosphorylation at Thr286 and sustained calcium-independent CaMKII activity after calcium signals dissipate. However, little is known about the mechanisms regulating striatal CaMKII. To address this, mouse brain slices were treated with pharmacological modulators of calcium channels and punches of dorsal striatum were immunoblotted for CaMKII Thr286 autophosphorylation as an index of CaMKII activation. KCl depolarization increased levels of CaMKII autophosphorylation ∼2-fold; this increase was blocked by an LTCC antagonist and was mimicked by treatment with pharmacological LTCC activators. The chelation of extracellular calcium robustly decreased basal CaMKII autophosphorylation within 5 min and increased levels of total CaMKII in cytosolic fractions, in addition to decreasing the phosphorylation of CaMKII sites in the GluN2B subunit of NMDA receptors and the GluA1 subunit of AMPA receptors. We also found that the maintenance of basal levels of CaMKII autophosphorylation requires low-voltage gated T-type calcium channels, but not LTCCs or R-type calcium channels. Our findings indicate that CaMKII activity is dynamically regulated by multiple calcium channels in the striatum thus coupling calcium entry to key downstream substrates.