Regulation of muscle Cav1.1 channels by long-term depolarization involves proteolysis of the alpha1s subunit.
Regulation of muscle Cav1.1 channels by long-term depolarization involves proteolysis of the alpha1s subunit.
复制标题
通过长期去极化对肌肉 Cav1.1 通道的调节涉及 α1s 亚基的蛋白水解。
DOI：
10.1007/s00232-004-0683-x
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发表时间：
2004
期刊：
影响因子：
--
通讯作者：
Sánchez,JA
中科院分区：
文献类型：
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作者：
Carrillo,E;Galindo,JM;García,MC;Sánchez,JA
评估长期去极化对蛙骨骼肌Cav1.1通道的影响。电压钳和Western-blot实验显示，长期去极化导致Cav1.1通道的电流幅值和肌肉l型通道的主要亚基α 1s亚基水平显著降低。蛋白酶抑制剂E64 （50 μM）和lepeptin （50 μM）抑制了这两种现象的下降。相反，长期去极化对α1s的辅助亚基β1没有影响。通过RNase保护实验检测α1和β1亚基编码mrna的水平。α1和β1亚基mrna的含量均不受长期去极化的影响，表明Cav1.1通道的合成不受影响。综上所述，我们的实验表明，膜电流振幅和α 1s亚基水平的降低是由Ca2+依赖性蛋白酶对该亚基的降解增加引起的。
The effects of long-term depolarization on frog skeletal muscle Cav1.1 channels were assessed. Voltage-clamp and Western-blot experiments revealed that long-term depolarization brings about a drastic reduction in the amplitude of currents flowing through Cav1.1 channels and in the levels of the α1ssubunit, the main subunit of muscle L-type channels. The decline of both phenomena was prevented by the action of the protease inhibitors E64 (50 μM) and leupeptin (50 μM). In contrast, long-term depolarization had no effect on β1, the auxiliary subunit of α1s. The levels of mRNAs coding the α1sand the β1subunits were measured by RNase protection assays. Neither the content of the α1snor the β1subunit mRNAs were affected by long-term depolarization, indicating that the synthesis of Cav1.1 channels remained unaffected. Taken together, our experiments suggest that the reduction in the amplitude of membrane currents and in the α1ssubunit levels is caused by increased degradation of this subunit by a Ca2+-dependent protease.