Potent and long-lasting inhibition of human P2X2 receptors by copper.
Potent and long-lasting inhibition of human P2X2 receptors by copper.
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DOI：
10.1016/j.neuropharm.2013.09.001
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发表时间：
2014-02
影响因子：
4.7
通讯作者：
Hume RI
中科院分区：
文献类型：
--
作者：
Punthambaker S;Hume RI
P2 X受体是由ATP门控的离子通道。在啮齿动物中，这些通道由锌和铜调节。锌与神经递质在某些突触处共同释放，可以调节神经元活动，但铜在大脑中的作用尚不清楚。大鼠P2 X2受体在存在次最大浓度ATP的情况下显示出2-100 µM锌或铜的增强作用，但在浓度高于100 µM时被锌或铜抑制。相比之下，人P2 X2（hP 2X2）受体没有表现出增强作用，并且在2-100 µM范围内被锌强烈抑制。铜对hP 2X2的影响是令人感兴趣的，因为存在其中铜浓度改变的人脑疾病。我们发现hP 2X2受体被铜有效抑制（IC 50 = 40 nM）。ATP反应性在铜洗脱后恢复非常缓慢，完全恢复需要超过1小时。ATP结合促进铜结合，但不从这个抑制性网站解结合。其中前六个细胞外半胱氨酸缺失的突变受体C（1-6）S显示正常的铜抑制，然而还原剂显著加速从野生型hP 2X2和C（1-6）S突变体中的铜抑制的恢复，表明需要最后两个二硫键来维持高亲和力铜结合位点。正常锌抑制所需的三个组氨酸残基也是正常铜抑制所需的。患有未经治疗的威尔逊病的人大脑中有过量的铜。hP 2X2受体的高铜敏感性表明它们在这些患者中无功能。
P2X receptors are ion channels gated by ATP. In rodents these channels are modulated by zinc and copper. Zinc is co-released with neurotransmitter at some synapses and can modulate neuronal activity, but the role of copper in the brain is unclear. Rat P2X2 receptors show potentiation by 2–100 µM zinc or copper in the presence of a submaximal concentration of ATP but are inhibited by zinc or copper at concentrations above 100 µM. In contrast, human P2X2 (hP2X2) receptors show no potentiation and are strongly inhibited by zinc over the range of 2–100 µM. The effect of copper on hP2X2 is of interest because there are human brain disorders in which copper concentration is altered. We found that hP2X2 receptors are potently inhibited by copper (IC50 = 40 nM). ATP responsiveness recovered extremely slowly after copper washout, with full recovery requiring over 1 h. ATP binding facilitated copper binding but not unbinding from this inhibitory site. A mutant receptor in which the first six extracellular cysteines were deleted, C(1–6)S, showed normal copper inhibition, however reducing agents dramatically accelerated recovery from copper inhibition in wild type hP2X2 and the C(1–6)S mutant, indicating that the final two disulfide bonds are required to maintain the high affinity copper binding site. Three histidine residues required for normal zinc inhibition were also required for normal copper inhibition. Humans with untreated Wilson’s disease have excess amounts of copper in the brain. The high copper sensitivity of hP2X2 receptors suggests that they are non-functional in these patients.
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影响因子：
64.8
作者：
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通讯作者：
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