PhD iCASE with Merck (USA): allosteric modulation of P2X ion channels

P2X受体是由细胞外腺苷5'-三磷酸（ATP）激活的配体门控离子通道。在哺乳动物中，P2X受体介导ATP在神经传递、疼痛刺激反应和血压调节过程中的快速生物学效应。人类基因组编码7个P2X受体（P2X1-7）。P2X受体是三聚体，由3个成孔亚基组装而成，形成一个由细胞外ATP门控的阳离子选择性孔。ATP结合位点（正位位点）位于亚基之间，在结构上高度保守。因此，与正位位点结合的药物样化合物不太可能提供受体亚型特异性。相反，变构位点在低进化压力下，可能在受体亚型之间表现出结构多样性。尽管取得了一些进展，但预测变构位点的识别仍然具有挑战性。与默克的合作将允许研究已知的P2X受体的小分子变构调节剂，以经验鉴定P2X受体内的变构位点。本项目将采用膜片钳电生理学、分子建模、钙成像、诱变和高通量筛选等方法，阐明P2X受体亚基变构调节的分子基础。

P2X receptors are ligand-gated ion channels activated by extracellular adenosine 5'-triphosphate (ATP). In mammals, fast biological effects of ATP are mediated by P2X receptors during neurotransmission, response to painful stimuli and regulation of blood pressure. The human genome encodes 7 P2X receptors (P2X1-7). P2X receptors are trimeric, formed by the assembly of 3 pore-forming subunits that form a cation-selective pore gated by extracellular ATP. The ATP binding site (orthosteric site) lies between subunits and is highly structurally conserved. Drug-like compounds that bind to the orthosteric site are therefore unlikely to offer receptor subtype specificity. Conversely, allosteric sites are under low evolutionary pressure and are likely to display structural diversity between receptor subtypes. Despite some progress, the predictive identification of allosteric sites remains challenging.A collaboration with Merck will allow for investigation of known small molecule allosteric modulators of P2X eceptors for empirical identification of allosteric sites within P2X receptors. The project will employ patch-clamp electrophysiology, molecular modelling, calcium imaging, mutagenesis and high-throughput screening to elucidate the molecular basis for allosteric modulation of P2X receptor subunits.