S-Palmitoylation of the sodium channel Nav1.6 regulates its activity and neuronal excitability
S-Palmitoylation of the sodium channel Nav1.6 regulates its activity and neuronal excitability
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钠通道Nav1.6的S-棕榈酰化调节其活性和神经元兴奋性
DOI：
10.1074/jbc.ra119.012423
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发表时间：
2020-05-01
影响因子：
4.8
通讯作者：
Cummins, Theodore R.
中科院分区：
文献类型：
--
作者：
Pan, Yanling;Xiao, Yucheng;Cummins, Theodore R.
S-棕榈酰化是一种动态调节蛋白质功能的可逆的翻译后脂质修饰。电压门控性钠通道经历S棕榈酰化，并在不同的S棕榈酰化状态下表现出不同的功能。我们的目的是研究S-棕榈酰化是否以及如何调节Nav1.6通道功能，并确定潜在的药理学靶点S-棕榈酰化位点。酰基-生物素交换实验表明，在小鼠脑内和稳定的HEK293细胞株中，Nav1.6被S棕榈酰化修饰。在全细胞电压钳上，我们发现用棕榈酸增强S棕榈酰化可增加NA1.6电流，而用2-溴棕榈酸酯阻断S棕榈酰化可降低Nav1.6电流并使稳态失活向超极化方向移动。鉴定出3个S棕榈酰化位点(Cys(1169)、Cys(1170)和Cys(1978))。这些站点以不同的方式调节不同的Nav1.6属性。有趣的是，Cys(1978)是所有NAV亚型中唯一的Nav1.6，并且在进化上在大多数物种中是保守的。Cys(1978)S-棕榈酰化在Nav1.6中独一无二地调节电流幅度。此外，我们还发现，取消特定位点的S棕榈酰化可以改变背根神经节神经元中Nav1.6介导的兴奋性。因此，我们的研究表明，在生理和疾病条件下，S棕榈酰化是一种潜在的异构体特异性机制，可以调节NAV的活性和神经元的兴奋性。
S-Palmitoylation is a reversible post-translational lipid modification that dynamically regulates protein functions. Voltage-gated sodium channels are subjected to S-palmitoylation and exhibit altered functions in different S-palmitoylation states. Our aim was to investigate whether and how S-palmitoylation regulates Nav1.6 channel function and to identify S-palmitoylation sites that can potentially be pharmacologically targeted. Acyl-biotin exchange assay showed that Nav1.6 is modified by S-palmitoylation in the mouse brain and in a Nav1.6 stable HEK 293 cell line. Using whole-cell voltage clamp, we discovered that enhancing S-palmitoylation with palmitic acid increases Nav1.6 current, whereas blocking S-palmitoylation with 2-bromopalmitate reduces Nav1.6 current and shifts the steady-state inactivation in the hyperpolarizing direction. Three S-palmitoylation sites (Cys(1169), Cys(1170), and Cys(1978)) were identified. These sites differentially modulate distinct Nav1.6 properties. Interestingly, Cys(1978) is exclusive to Nav1.6 among all Nav isoforms and is evolutionally conserved in Nav1.6 among most species. Cys(1978) S-palmitoylation regulates current amplitude uniquely in Nav1.6. Furthermore, we showed that eliminating S-palmitoylation at specific sites alters Nav1.6-mediated excitability in dorsal root ganglion neurons. Therefore, our study reveals S-palmitoylation as a potential isoform-specific mechanism to modulate Nav activity and neuronal excitability in physiological and diseased conditions.