Modulation of the alpha 1A Ca2+ channel by beta subunits at physiological Ca2+ concentration
Modulation of the alpha 1A Ca2+ channel by beta subunits at physiological Ca2+ concentration
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DOI：
10.1016/0014-5793(96)00704-1
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发表时间：
1996-08-12
期刊：
影响因子：
3.5
通讯作者：
Charnet, P
中科院分区：
文献类型：
--
作者：
Cens, T;Mangoni, ME;Charnet, P
在非洲爪蟾卵母细胞中单独或与β 1b、β 2a、β 3或β 4亚基组合表达的A类Ca2+通道α 1亚基（α 1A）mas，与在40 mM Ba2+存在下进行的类似记录相比，在1.8 mM外部Ca2+存在下的电压依赖性激活和失活分析显示两种关系的超极化位移。活化和失活的这些变化不同，仅受共表达β亚基性质的强烈调节。另一方面，对于每种组合，在1.8 mM Ca 2+和30 mM Ba 2+中失活的动力学相似（例如，β 2a亚基的共表达减少了使用40mMBa2+或1.8mMCa2+的失活）。因此，β亚基对通道特性的调节在生理Ca 2+或高Ba 2+浓度下是不同的。必须考虑这些结果，以推断β亚基在天然细胞中的作用。
The class A Ca2+ channel alpha 1 subunit (alpha 1A) mas expressed in Xenopus oocytes alone or in combination with the beta 1b, beta 2a, beta 3, or beta 4 subunit, Analysis of voltage-dependent activation and inactivation in the presence of 1.8 mM external Ca2+ showed an hyperpolarising shift of both relations when compared to similar recordings performed in the presence of 40 mM Ba2+. These shifts, which differed for activation and inactivation, mere strongly modulated by the nature of the co-expressed beta subunit, On the other hand, for each combination, the kinetics of inactivation were similar in 1.8 mM Ca2+ and 30 mM Ba2+ (for example co-expression of the beta 2a subunit reduced inactivation using either 40 mM Ba2+ or 1.8 mM Ca2+), Thus, modulation of channel properties by the beta subunit is different in physiological Ca2+ or high Ba2+ concentrations. These results must be taken into consideration to extrapolate the role of the beta subunit in native cells.