Altered allostery of the left flipper domain underlies the weak ATP response of rat P2X5 receptors
Altered allostery of the left flipper domain underlies the weak ATP response of rat P2X5 receptors
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左鳍结构域的变构改变是大鼠 P2X5 受体弱 ATP 反应的基础
DOI：
10.1074/jbc.ra119.009959
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发表时间：
2019-12-20
影响因子：
4.8
通讯作者：
Yu，Ye
中科院分区：
文献类型：
--
作者：
Sun，Liang-Fei;Liu，Yan;Yu，Ye
虽然细胞外ATP门控阳离子通道嘌呤受体P2 X5广泛表达于哺乳动物的心脏、骨骼肌、免疫和神经系统，但对其功能和通道门控活性知之甚少。这种知识的缺乏是由于P2 X5在几种哺乳动物物种中的弱ATP反应，如人类，大鼠和小鼠。野生型人P2 X5（hP 2X 5 Δ328-349）对ATP无应答，而全长变体hP 2X 5（hP 2X 5-FL）（包含编码第二个hP 2X 5跨膜结构域（TM 2）的外显子10）对ATP有应答。然而，虽然大鼠P2 X5（rP 2X 5）有一个全长的TM 2，ATP只诱导弱电流的rP 2X 5，这促使我们研究这种小ATP反应的机制。在这里，我们表明，特定的rP 2X 5的残基与hP 2X 5（S191 F或F195 H）中的相应残基的单取代显着增强电流的振幅rP 2X 5。使用工程二硫键交联，单通道记录和分子建模的组合，我们询问了S191 F和F195 H取代对左鳍状（LF）结构域变构的影响。我们的研究结果的基础上，我们提出，绑定ATP诱导的LF域与其他功能亚型的不同变构引起了弱ATP反应的rP 2X 5受体。本研究结果为今后转基因研究P2 X5受体的生理和病理功能奠定了基础。
Although the extracellular ATP-gated cation channel purinergic receptor P2X5 is widely expressed in heart, skeletal muscle, and immune and nervous systems in mammals, little is known about its functions and channel-gating activities. This lack of knowledge is due to P2X5's weak ATP responses in several mammalian species, such as humans, rats, and mice. WT human P2X5 (hP2X5Δ328–349) does not respond to ATP, whereas a full-length variant, hP2X5 (hP2X5-FL), containing exon 10 encoding the second hP2X5 transmembrane domain (TM2), does. However, although rat P2X5 (rP2X5) has a full-length TM2, ATP induces only weak currents in rP2X5, which prompted us to investigate the mechanism underlying this small ATP response. Here, we show that single replacements of specific rP2X5 residues with the corresponding residues in hP2X5 (S191F or F195H) significantly enhance the current amplitude of rP2X5. Using a combination of engineered disulfide cross-linking, single-channel recording, and molecular modeling, we interrogated the effects of S191F and F195H substitutions on the allostery of the left flipper (LF) domain. On the basis of our findings, we propose that the bound ATP-induced distinct allostery of the LF domain with that of other functional subtypes has caused the weak ATP response of rP2X5 receptors. The findings of our study provide the prerequisite for future transgenic studies on the physiological and pathological functions of P2X5 receptors.