Functional characterization of a P2X receptor from Schistosoma mansoni
Functional characterization of a P2X receptor from Schistosoma mansoni
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DOI：
10.1074/jbc.m408203200
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发表时间：
2004-10-01
影响因子：
4.8
通讯作者：
Ennion, SJ
中科院分区：
文献类型：
--
作者：
Agboh, KC;Webb, TE;Ennion, SJ
寄生血吸虫曼氏血吸虫P2 X受体（schP 2X）的克隆和表征提供了非脊椎动物ATP门控离子通道的第一个例子。在脊椎动物P2 X受体中保守的许多功能上重要的氨基酸残基，包括10个细胞外半胱氨酸，参与ATP识别的芳香族和带正电荷的残基，以及氨基末端尾中的共有蛋白激酶C位点，也存在于schP 2X中。总体而言，schP 2X与人P2 X（1-7）受体的氨基酸序列同一性范围为25.8%至36.6%。ATP在非洲爪蟾卵母细胞中表达的schP 2X通道上诱发浓度依赖性电流，EC 50为22.1 μ M。2 '，3'-O-（4-Benzoylbenzoyl）adenosine 5 '-triphosphate（Bz-ATP）是一种部分激动剂（最大反应为ATP的75.4 +/-4.4%），具有比ATP更高的效力（EC 50为3.6 μ M）。苏拉明和吡哆醛-磷酸-6-偶氮苯基-2 '，4'-二磺酸阻断schP 2X对100 μ M ATP的反应，IC 50值分别为9.6和0.5 μ M。伊维菌素（10 μ M）可使ATP和Bz-ATP的电流增强60%，对效价的影响极小（EC 50分别为18.2和1.6 μ M）。在双离子条件下测定HEK 293细胞中表达的schP 2X对各种阳离子的相对渗透性。schP 2X具有相对高的钙渗透性（P-Ca/P-Na = 3.80 +/-0.29）和与脊椎动物P2 X受体相似的估计最小孔径。SchP 2X为更好地了解人类P2 X受体功能提供了一个有用的比较模型，也可能为治疗血吸虫病提供一个替代的药物靶点。
The cloning and characterization of a P2X receptor (schP2X) from the parasitic blood fluke Schistosoma mansoni provides the first example of a non-vertebrate ATP-gated ion channel. A number of functionally important amino acid residues conserved throughout vertebrate P2X receptors, including 10 extracellular cysteines, aromatic and positively charged residues involved in ATP recognition, and a consensus protein kinase C site in the amino-terminal tail, are also present in schP2X. Overall, the amino acid sequence identity of schP2X with human P2X(1-7) receptors ranges from 25.8 to 36.6%. ATP evoked concentration-dependent currents at schP2X channels expressed in Xenopus oocytes with an EC50 of 22.1 muM. 2', 3'-O-(4-Benzoylbenzoyl) adenosine 5'-triphosphate (Bz-ATP) was a partial agonist ( maximum response 75.4 +/- 4.4% that of ATP) with a higher potency (EC50 of 3.6 muM) than ATP. Suramin and pyridoxal-phosphate-6- azophenyl- 2', 4'-disulfonic acid blocked schP2X responses to 100 muM ATP with IC50 values of 9.6 and 0.5 muM, respectively. Ivermectin ( 10 muM) potentiated currents to both ATP and Bz-ATP by similar to 60% with a minimal effect on potency (EC50 of 18.2 and 1.6 muM, respectively). The relative permeability of schP2X expressed in HEK293 cells to various cations was determined under bi-ionic conditions. schP2X has a relatively high calcium permeability (P-Ca/P-Na = 3.80 +/- 0.29) and an estimated minimum pore diameter similar to that of vertebrate P2X receptors. SchP2X provides a useful comparative model for the better understanding of human P2X receptor function and may also provide an alternative drug target for treatment of schistosomiasis.