Tryptophan 46 is a site for ethanol and ivermectin action in P2X4 receptors.
Tryptophan 46 is a site for ethanol and ivermectin action in P2X4 receptors.
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色氨酸 46 是 P2X4 受体中乙醇和伊维菌素作用的位点。
DOI：
10.1007/s11302-013-9373-4
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发表时间：
2013
影响因子：
3.5
通讯作者：
Asatryan,Liana
中科院分区：
文献类型：
--
作者：
Popova,Maya;Trudell,James;Li,Kaixun;Alkana,Ronald;Davies,Daryl;Asatryan,Liana
ATP 门控嘌呤能 P2X4 受体 (P2X4R) 是对酒精最敏感的 P2XR 亚型。我们最近报道了伊维菌素（IVM），一种用于动物和人类的抗寄生虫药，可以拮抗乙醇对 P2X4R 的抑制。此外，IVM 还减少了小鼠的乙醇摄入量。大鼠 P2X4R 的第一个分子模型建立在斑马鱼 P2X4R 的 X 射线晶体结构上，揭示了由 TM2 中的 Asp331、Met336 以及 TM1 片段中的 Trp46 和 Trp50 形成的乙醇和 IVM 的作用袋。 Asp331 和 Met336 的作用已通过实验得到证实。本研究验证了 Trp46 在乙醇和 IVM P2X4R 调节中发挥作用的假设。 Trp46 突变为具有不同理化特性的残基，并使用爪蟾细胞表达系统和两电极电压钳测试所得突变体的乙醇和 IVM 反应。 46 位的非芳香族取代降低了较高浓度下的乙醇抑制，并将 IVM 增强作用转变为抑制作用。 Trp46 和 Met336 位点的丙氨酸同时取代也导致乙醇和 IVM 反应的类似变化。此外，基于斑马鱼 P2X4R 开孔构象的新分子模型表明 Tyr42 的作用得到了实验的进一步支持。我们之前和当前的研究结果，结合我们在 P2X4R 敲除小鼠中乙醇消耗增加的初步证据，表明 P2X4R 中由 42、46、331 和 336 位形成的乙醇和 IVM 作用袋为酒精使用障碍的药物开发提供了潜在的靶点。
ATP-gated purinergic P2X4 receptors (P2X4Rs) are the most alcohol-sensitive P2XR subtype. We recently reported that ivermectin (IVM), an antiparasitic used in animals and humans, antagonized ethanol inhibition of P2X4Rs. Furthermore, IVM reduced ethanol intake in mice. The first molecular model of the rat P2X4R, built onto the X-ray crystal structure of zebrafish P2X4R, revealed an action pocket for both ethanol and IVM formed by Asp331, Met336 in TM2 and Trp46, and Trp50 in TM1 segments. The role of Asp331 and Met336 was experimentally confirmed. The present study tested the hypothesis that Trp46 plays a role in ethanol and IVM modulation of P2X4Rs. Trp46 was mutated to residues with different physicochemical properties and the resultant mutants tested for ethanol and IVM responses usingXenopusoocyte expression system and two-electrode voltage clamp. Nonaromatic substitutions at position 46 reduced ethanol inhibition at higher concentrations and switched IVM potentiation to inhibition. Simultaneous substitution of alanine at positions Trp46 and Met336 also resulted in similar changes in ethanol and IVM responses. Furthermore, a new molecular model based on the open pore conformation of zebrafish P2X4R suggested a role for Tyr42 that was further supported experimentally. Our previous and current findings, combined with our preliminary evidence of increased ethanol consumption in P2X4R knockout mice, suggest that the ethanol and IVM action pocket in P2X4Rs formed by positions 42, 46, 331, and 336 presents a potential target for medication development for alcohol use disorders.