A V-to-F substitution in SK2 channels causes Ca(2+) hypersensitivity and improves locomotion in a C. elegans ALS model.
A V-to-F substitution in SK2 channels causes Ca(2+) hypersensitivity and improves locomotion in a C. elegans ALS model.
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DOI：
10.1038/s41598-018-28783-2
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发表时间：
2018-07-16
影响因子：
4.6
通讯作者：
Zhang M
中科院分区：
文献类型：
--
作者：
Nam YW;Baskoylu SN;Gazgalis D;Orfali R;Cui M;Hart AC;Zhang M
小电导Ca~(2+)激活的K~+(SK)通道在神经元兴奋性的调节中起着关键作用。SK通道是共济失调和肌萎缩侧索硬化症(ALS)的潜在药物靶点。SK通道只被钙离子结合的钙调蛋白激活。在此之前，我们发现了一个内在的无序片段，它对于钙/钙调蛋白结合和通道开放之间的机械耦合是必不可少的。在这里，我们报告了在固有的无序片段中用Valine取代苯丙氨酸(V407F)导致SK2-a通道对Ca~(2+)敏感性增加~6倍。这种取代导致了异位苯丙氨酸和M411之间的一种新的相互作用，稳定了PIP2相互作用的残基K405，并随后增强了对钙的敏感性。此外，在SK1或SK3通道中，相当于苯丙氨酸取代的Valine可产生钙超敏反应。线虫(C.elegans)SK2直系同源kcnl-2中的等量苯丙氨酸替代部分修复了现有线虫ALS模型中的运动缺陷，在该模型中，人SOD1G85R在神经元中高水平表达，证实了这种苯丙氨酸替代影响了体内的通道功能。这项工作首次为未来的研究提供了一个关键试剂：一种在体内对钙离子高度敏感的SK通道。
Small-conductance Ca2+-activated K+ (SK) channels mediate medium afterhyperpolarization in the neurons and play a key role in the regulation of neuronal excitability. SK channels are potential drug targets for ataxia and Amyotrophic Lateral Sclerosis (ALS). SK channels are activated exclusively by the Ca2+-bound calmodulin. Previously, we identified an intrinsically disordered fragment that is essential for the mechanical coupling between Ca2+/calmodulin binding and channel opening. Here, we report that substitution of a valine to phenylalanine (V407F) in the intrinsically disordered fragment caused a ~6 fold increase in the Ca2+ sensitivity of SK2-a channels. This substitution resulted in a novel interaction between the ectopic phenylalanine and M411, which stabilized PIP2-interacting residue K405, and subsequently enhanced Ca2+ sensitivity. Also, equivalent valine to phenylalanine substitutions in SK1 or SK3 channels conferred Ca2+ hypersensitivity. An equivalent phenylalanine substitution in the Caenorhabditis elegans (C. elegans) SK2 ortholog kcnl-2 partially rescued locomotion defects in an existing C. elegans ALS model, in which human SOD1G85R is expressed at high levels in neurons, confirming that this phenylalanine substitution impacts channel function in vivo. This work for the first time provides a critical reagent for future studies: an SK channel that is hypersensitive to Ca2+ with increased activity in vivo.
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DOI：
10.1085/jgp.200910295
发表时间：
2009-10
期刊：
The Journal of general physiology
影响因子：
--
作者：
Li W;Halling DB;Hall AW;Aldrich RW
通讯作者：
Aldrich RW
影响因子：
6.1
作者：
Luna-Cancalon K;Sikora KM;Pappas SS;Singh V;Wulff H;Paulson HL;Burmeister M;Shakkottai VG
通讯作者：
Shakkottai VG
DOI：
10.1523/jneurosci.1536-12.2013
发表时间：
2013-04-10
期刊：
The Journal of neuroscience : the official journal of the Society for Neuroscience
影响因子：
--
作者：
Dimitriadi M;Kye MJ;Kalloo G;Yersak JM;Sahin M;Hart AC
通讯作者：
Hart AC
影响因子：
4.5
作者：
Dimitriadi M;Sleigh JN;Walker A;Chang HC;Sen A;Kalloo G;Harris J;Barsby T;Walsh MB;Satterlee JS;Li C;Van Vactor D;Artavanis-Tsakonas S;Hart AC
通讯作者：
Hart AC
影响因子：
3.7
作者：
Chotoo CK;Silverman GA;Devor DC;Luke CJ
通讯作者：
Luke CJ