Interaction between Calcineurin and Ca/Calmodulin Kinase-II in Modulating Cellular Functions.
Interaction between Calcineurin and Ca/Calmodulin Kinase-II in Modulating Cellular Functions.
复制标题
DOI：
10.4061/2011/587359
复制
发表时间：
2011
期刊：
影响因子：
--
通讯作者：
Komagiri Y
中科院分区：
文献类型：
--
作者：
Kubokawa M;Nakamura K;Komagiri Y
钙调神经磷酸酶（CaN）和钙调蛋白依赖性蛋白激酶Ⅱ（CaMK Ⅱ）对肾小管上皮细胞K+通道活性和细胞内Ca ~（2+）浓度（[Ca ~（2+）]i）的调节作用已被研究。采用膜片钳技术记录细胞膜通道电流，Fura-2成像技术检测细胞内[Ca ~（2+）]i。我们发现CaN抑制剂环孢菌素A（CyA）降低了K+通道活性，升高了[Ca ~（2+）]i，表明CyA关闭了K+通道，打开了胞浆Ca ~（2+）库的Ca ~（2+）释放通道。此外，这两种反应都被CaMKII抑制剂KN-62阻断。这表明CyA介导的反应是由CaMKII激活引起的。事实上，蛋白质印迹分析显示，CyA增加磷酸化CaMKII，一种活性形式的CaMKII。这些发现表明，CaN依赖性去磷酸化抑制CaMKII介导的磷酸化，并且CaN的抑制增加磷酸化CaMKII，这导致CaMKII依赖性细胞作用的刺激。
Roles of calcineurin (CaN), a Ca2+/calmodulin- (CaM-) dependent protein phosphatase, and Ca2+/CaM-dependent protein kinase-II (CaMKII) in modulating K+ channel activity and the intracellular Ca2+ concentration ([Ca2+]i) have been investigated in renal tubule epithelial cells. The channel current through the cell membrane was recorded with the patch-clamp technique, and [Ca2+]i was monitored using fura-2 imaging. We found that a CaN-inhibitor, cyclosporin A (CyA), lowered the K+ channel activity and elevated [Ca2+]i, suggesting that CyA closes K+ channels and opens Ca2+-release channels of the cytosolic Ca2+-store. Moreover, both of these responses were blocked by KN-62, an inhibitor of CaMKII. It is suggested that the CyA-mediated response results from the activation of CaMKII. Indeed, Western blot analysis revealed that CyA increased phospho-CaMKII, an active form of CaMKII. These findings suggest that CaN-dependent dephosphorylation inhibits CaMKII-mediated phosphorylation, and the inhibition of CaN increases phospho-CaMKII, which results in the stimulation of CaMKII-dependent cellular actions.