Tang Cheng, Duran Paz, Calderon-Rivera Aida, Loya-Lopez Santiago, Gomez Kimberly, Perez-Miller Samantha, Khanna Rajesh
Department of Molecular Pathobiology, College of Dentistry, New York University, New York, NY 10010, USA.
The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha 410081, China.
PNAS Nexus. 2024 Jun 4;3(6):pgae222. doi: 10.1093/pnasnexus/pgae222. eCollection 2024 Jun.
-palmitoylation, a reversible lipid post-translational modification, regulates the functions of numerous proteins. Voltage-gated sodium channels (Nas), pivotal in action potential generation and propagation within cardiac cells and sensory neurons, can be directly or indirectly modulated by -palmitoylation, impacting channel trafficking and function. However, the role of -palmitoylation in modulating Na1.7, a significant contributor to pain pathophysiology, has remained unexplored. Here, we addressed this knowledge gap by investigating if -palmitoylation influences Na1.7 channel function. Acyl-biotin exchange assays demonstrated that heterologously expressed Na1.7 channels are modified by -palmitoylation. Blocking -palmitoylation with 2-bromopalmitate resulted in reduced Na1.7 current density and hyperpolarized steady-state inactivation. We identified two -palmitoylation sites within Na1.7, both located in the second intracellular loop, which regulated different properties of the channel. Specifically, -palmitoylation of cysteine 1126 enhanced Na1.7 current density, while -palmitoylation of cysteine 1152 modulated voltage-dependent inactivation. Blocking -palmitoylation altered excitability of rat dorsal root ganglion neurons. Lastly, in human sensory neurons, Na1.7 undergoes -palmitoylation, and the attenuation of this post-translational modification results in alterations in the voltage-dependence of activation, leading to decreased neuronal excitability. Our data show, for the first time, that -palmitoylation affects Na1.7 channels, exerting regulatory control over their activity and, consequently, impacting rodent and human sensory neuron excitability. These findings provide a foundation for future pharmacological studies, potentially uncovering novel therapeutic avenues in the modulation of -palmitoylation for Na1.7 channels.
棕榈酰化是一种可逆的脂质翻译后修饰，可调节众多蛋白质的功能。电压门控钠通道（Na通道）在心脏细胞和感觉神经元的动作电位产生和传播中起关键作用，可直接或间接受到棕榈酰化的调节，影响通道的运输和功能。然而，棕榈酰化在调节Na1.7（疼痛病理生理学的重要促成因素）中的作用尚未得到探索。在此，我们通过研究棕榈酰化是否影响Na1.7通道功能来填补这一知识空白。酰基生物素交换试验表明，异源表达的Na1.7通道被棕榈酰化修饰。用2-溴棕榈酸阻断棕榈酰化会导致Na1.7电流密度降低和超极化稳态失活。我们在Na1.7中鉴定出两个棕榈酰化位点，均位于第二个细胞内环，它们调节通道的不同特性。具体而言，半胱氨酸1126的棕榈酰化增强了Na1.7电流密度，而半胱氨酸1152的棕榈酰化调节了电压依赖性失活。阻断棕榈酰化改变了大鼠背根神经节神经元的兴奋性。最后，在人类感觉神经元中，Na1.7发生棕榈酰化，这种翻译后修饰的减弱会导致激活电压依赖性的改变，从而导致神经元兴奋性降低。我们的数据首次表明，棕榈酰化影响Na1.7通道，对其活性进行调节控制，进而影响啮齿动物和人类感觉神经元的兴奋性。这些发现为未来的药理学研究奠定了基础，可能揭示调节Na1.7通道棕榈酰化的新治疗途径。
