A calcium switch for the functional coupling between a (hslo) and beta subunits (K-v,K-Ca beta) of maxi K channels
A calcium switch for the functional coupling between a (hslo) and beta subunits (K-v,K-Ca beta) of maxi K channels
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DOI：
10.1016/0014-5793(96)00151-2
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发表时间：
1996-03-11
期刊：
影响因子：
3.5
通讯作者：
Toro, L
中科院分区：
文献类型：
--
作者：
Meera, P;Wallner, M;Toro, L
当在微摩尔 [Ca2+](i) 范围内进行探测时，K-V?(Ca)beta 亚基显着增加 MaxiK 通道 α 亚基的表观钙敏感性。对大范围 [Ca2+](i) 的分析表明，这种功能耦合受到 [Ca2+](i) 的精细调节。 Ca2+ 离子在浓度超出静息 [Ca2+](i) 时将 MaxiK α+β 复合物转变为功能耦合状态。当 [Ca2+] 小于或等于 100 nM 时，MaxiK 活性变得独立于 Ca2+，完全由电压激活，并且其与其 β 亚基的功能耦合被释放。功能开关在细胞兴奋期间发生的 [Ca2+](i) 处发生，为 MaxiK 通道如何调节平滑肌兴奋性和神经递质释放提供了分子基础。
K-V?(Ca)beta subunit dramatically increases the apparent calcium sensitivity of the alpha subunit of MaxiK channels when probed in the micromolar [Ca2+](i) range, Analysis in a wide range of [Ca2+](i) revealed that this functional coupling is exquisitely modulated by [Ca2+](i). Ca2+ ions switch MaxiK alpha+beta complex into a functionally coupled state at concentrations beyond resting [Ca2+](i). At [Ca2+] less than or equal to 100 nM, MaxiK activity becomes independent of Ca2+, is purely voltage-activated, and its functional coupling with its beta subunit is released. The functional switch develops at [Ca2+](i) that occur during cellular excitation, providing the molecular basis of how MaxiK channels regulate smooth muscle excitability and neurotransmitter release.