Slo3 K+ channels: voltage and pH dependence of macroscopic currents.
Slo3 K+ channels: voltage and pH dependence of macroscopic currents.
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Slo3 K+通道：宏观电流的电压和pH依赖性。
DOI：
10.1085/jgp.200609552
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发表时间：
2006-09
期刊：
影响因子：
--
通讯作者：
Lingle CJ
中科院分区：
文献类型：
--
作者：
Zhang X;Zeng X;Lingle CJ
The mouse Slo3 gene (KCNMA3) encodes a K+ channel that is regulated by changes in cytosolic pH. Like Slo1 subunits responsible for the Ca2+ and voltage-activated BK-type channel, the Slo3 α subunit contains a pore module with homology to voltage-gated K+ channels and also an extensive cytosolic C terminus thought to be responsible for ligand dependence. For the Slo3 K+ channel, increases in cytosolic pH promote channel activation, but very little is known about many fundamental properties of Slo3 currents. Here we define the dependence of macroscopic conductance on voltage and pH and, in particular, examine Slo3 conductance activated at negative potentials. Using this information, the ability of a Horrigan-Aldrich–type of general allosteric model to account for Slo3 gating is examined. Finally, the pH and voltage dependence of Slo3 activation and deactivation kinetics is reported. The results indicate that Slo3 differs from Slo1 in several important ways. The limiting conductance activated at the most positive potentials exhibits a pH-dependent maximum, suggesting differences in the limiting open probability at different pH. Furthermore, over a 600 mV range of voltages (−300 to +300 mV), Slo3 conductance shifts only about two to three orders of magnitude, and the limiting conductance at negative potentials is relatively voltage independent compared to Slo1. Within the context of the Horrigan-Aldrich model, these results indicate that the intrinsic voltage dependence (zL) of the Slo3 closed–open equilibrium and the coupling (D) between voltage sensor movement are less than in Slo1. The kinetic behavior of Slo3 currents also differs markedly from Slo1. Both activation and deactivation are best described by two exponential components, both of which are only weakly voltage dependent. Qualitatively, the properties of the two kinetic components in the activation time course suggest that increases in pH increase the fraction of more rapidly opening channels.
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DOI：
10.1085/jgp.112.1.33
发表时间：
1998-07
期刊：
The Journal of general physiology
影响因子：
--
作者：
Santi CM;Santos T;Hernández-Cruz A;Darszon A
通讯作者：
Darszon A
DOI：
10.1085/jgp.109.5.647
发表时间：
1997-05
期刊：
The Journal of general physiology
影响因子：
--
作者：
Cui J;Cox DH;Aldrich RW
通讯作者：
Aldrich RW
每通道总充电移动。门控电荷位移与激活的电压灵敏度之间的关系。
影响因子：
3.8
作者：
Sigg, D;Bezanilla, F
通讯作者：
Bezanilla, F
DOI：
10.1085/jgp.118.6.711
发表时间：
2001-12
期刊：
The Journal of general physiology
影响因子：
--
作者：
Moss BL;Magleby KL
通讯作者：
Magleby KL
影响因子：
3.4
作者：
Avdonin, V;Tang, XD;Hoshi, T
通讯作者：
Hoshi, T