Point mutation in the mouse P2X7 receptor affects intercellular calcium waves in astrocytes.
Point mutation in the mouse P2X7 receptor affects intercellular calcium waves in astrocytes.
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DOI：
10.1042/an20090001
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发表时间：
2009-04-14
期刊：
影响因子：
4.7
通讯作者：
Scemes E
中科院分区：
文献类型：
--
作者：
Suadicani SO;Iglesias R;Spray DC;Scemes E
嘌呤能P2受体和缝隙连接是两组参与星形胶质细胞间ICW（细胞间钙波）传递的蛋白质。ICW在这些神经胶质细胞中扩散的程度取决于释放的ATP的量，这可以通过膜通道以及其他途径发生。我们以前的研究表明，成孔P2 X7 R（P2 X7受体）有助于扩大ICW的蔓延，通过Panx 1（Pannexin 1）通道提供ATP释放的网站。为了深入了解介导这种反应的信号转导事件，我们比较了星形胶质细胞中P2 X7 R-Panx 1复合物的性质，该复合物来自在P2 X7 R的C末端含有天然点突变（P451 L）的小鼠品系（C57 Bl/6）与非突变受体（Balb/C小鼠）。电生理学、生物化学、药理学和荧光成像技术显示，位于P2 X7 R C-末端的SH 3结构域（Src酪氨酸激酶结合位点）的P451 L突变减弱了Panx 1电流、ATP释放和星形胶质细胞间ICW传播的距离。当使用Src酪氨酸抑制剂（PP 2）和跨C57 B16星形胶质细胞的P2 X7 R的P451 L突变的膜渗透肽时，获得了类似的结果。这些结果支持Src家族的酪氨酸激酶参与介导P2 X7 R刺激后Panx 1通道开放的初始步骤，以及星形胶质细胞之间钙信号的传递。
Purinergic P2 receptors and gap junctions are two groups of proteins involved in the transmission of ICWs (intercellular calcium waves) between astrocytes. The extent to which ICWs spread among these glial cells depends on the amount of ATP released, which can occur through membrane channels, as well as other pathways. Our previous studies have shown that the pore-forming P2X7R (P2X7 receptor) contributes to the amplification of ICW spread by providing sites of ATP release through Panx1 (Pannexin1) channels. To gain insight into the signal transduction events mediating this response we compared the properties of the P2X7R–Panx1 complex in astrocytes from a mouse strain (C57Bl/6) containing a naturally occurring point mutation (P451L) in the C-terminus of the P2X7R to that of non-mutated receptors (Balb/C mice). Electrophysiological, biochemical, pharmacological and fluorescence imaging techniques revealed that the P451L mutation located in the SH3 domain (a Src tyrosine kinase-binding site) of the C-terminus of the P2X7R attenuates Panx1 currents, ATP release and the distance of ICW spread between astrocytes. Similar results were obtained when using the Src tyrosine inhibitor (PP2) and a membrane-permeant peptide spanning the P451L mutation of the P2X7R of the C57Bl6 astrocytes. These results support the participation of a tyrosine kinase of the Src family in the initial steps mediating the opening of Panx1 channels following P2X7R stimulation and in the transmission of calcium signals among astrocytes.