P2X2 and P2X5 Subunits Define a New Heteromeric Receptor with P2X7-Like Properties
P2X2 and P2X5 Subunits Define a New Heteromeric Receptor with P2X7-Like Properties
复制标题
DOI：
10.1523/jneurosci.6332-11.2012
复制
发表时间：
2012-03-21
影响因子：
5.3
通讯作者：
Rassendren, Francois
中科院分区：
文献类型：
--
作者：
Compan, Vincent;Ulmann, Lauriane;Rassendren, Francois
配体门控离子通道是一种典型的寡聚膜蛋白，其化学计量决定了其功能特性和亚细胞定位。破译这种蛋白质复合物的四级结构是一项艰巨的任务，通常需要多种方法的结合。ATP门控P2 X受体由三个亚基的缔合形成，但质膜上七个P2 X亚基的四元排列仍不清楚。通过结合生物发光共振能量转移，双功能荧光互补和蛋白质生物化学，我们开发了一种实验方法，可以精确测定大鼠P2 X受体四级组装。我们发现P2 X5亚基与P2 X1、P2 X2和P2 X4亚基相关。我们证明，P2 X5和P2 X2亚基相互作用，形成尚未表征的异聚受体与交替的化学计量，都存在于质膜。P2 X2/5受体显示功能特性，如孔扩张、膜起泡和磷脂酰丝氨酸暴露，这些以前被认为是P2 X7受体的特征性标志。在小鼠中，P2 X2和P2 X5亚基共定位并在特定的神经元群体中物理相互作用，表明其他P2 X受体可能有助于通常归因于P2 X7受体的细胞反应。
Ligand-gated ion channels are prototypic oligomeric membrane proteins whose stoichiometry determines their functional properties and subcellular localization. Deciphering the quaternary structure of such protein complexes is an arduous task and usually requires the combination of multiple approaches. ATP-gated P2X receptors are formed by the association of three subunits, but the quaternary arrangement of the seven P2X subunits at the plasma membrane remains poorly characterized. By combining bioluminescence resonance energy transfer, bifunctional fluorescence complementation and protein biochemistry, we developed an experimental approach that allows precise determination of rat P2X receptor quaternary assembly. We found that P2X5 subunits associate with P2X1, P2X2, and P2X4 subunits. We demonstrate that P2X5 and P2X2 subunits interact to form as yet uncharacterized heteromeric receptors with alternate stoichiometries, both present at the plasma membrane. P2X2/5 receptors display functional properties such as pore dilatation, membrane blebbing, and phosphatidylserine exposure that were previously thought to be characteristic hallmarks of the P2X7 receptor. In mouse, P2X2 and P2X5 subunits colocalize and physically interact in specific neuronal populations suggesting that other P2X receptors might contribute to cellular responses typically attributed to P2X7 receptor.