Stimulatory action of internal protons on Slo1 BK channels
Stimulatory action of internal protons on Slo1 BK channels
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DOI：
10.1016/s0006-3495(03)70023-x
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发表时间：
2003-05-01
影响因子：
3.4
通讯作者：
Hoshi, T
中科院分区：
文献类型：
--
作者：
Avdonin, V;Tang, XD;Hoshi, T
我们研究了异源表达的hSlo1 BK通道的内部pH敏感性。在虚拟的情况下的Ca2+和Mg2+隔离的电压依赖性门控转换，低内部pH值增强宏观hSlo1电流通过转移的电压依赖性激活更负的电压。低pH值时，激活时间进程较快，失活时间进程较慢。刺激效应的Kd值约为pH = 6.5或0.35 μ M。当辅助亚基小鼠β 1共表达时，刺激作用得以维持。用组氨酸修饰剂焦碳酸二乙酯处理hSlo1通道也增强了hSlo1电流，并大大降低了内部pH敏感性，这表明焦碳酸二乙酯和低pH可能对相同的效应机制起作用。高浓度的Ca2+或Mg2+也掩盖了低内部pH值的刺激作用。这些结果表明，酸敏感性的hSlo1 BK通道可能涉及的通道域牵连的二价依赖性激活。
We investigated the internal pH-sensitivity of heterologously expressed hSlo1 BK channels. In the virtual absence of Ca2+ and Mg2+ to isolate the voltage-dependent gating transitions, low internal pH enhanced macroscopic hSlo1 currents by shifting the voltage-dependence of activation to more negative voltages. The activation time course was faster and the deactivation time course was slower with low pH. The estimated K-d value of the stimulatory effect was approximately pH = 6.5 or 0.35 muM. The stimulatory effect was maintained when the auxiliary subunit mouse beta1 was coexpressed. Treatment of the hSlo1 channel with the histidine modifying agent diethyl pyrocarbonate also enhanced the hSlo1 currents and greatly diminished the internal pH sensitivity, suggesting that diethyl pyrocarbonate and low pH may work on the same effector mechanism. High concentrations of Ca2+ or Mg2+ also masked the stimulatory effect of low internal pH. These results indicate that the acid-sensitivity of the hSlo1 BK channel may involve the channel domain implicated in the divalent-dependent activation.