Differential regulation and relocalization of the platelet P2Y receptors after activation:: A way to avoid loss of hemostatic properties?
Differential regulation and relocalization of the platelet P2Y receptors after activation:: A way to avoid loss of hemostatic properties?
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DOI：
10.1124/mol.104.004846
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发表时间：
2005-03-01
影响因子：
3.6
通讯作者：
Gachet, C
中科院分区：
文献类型：
--
作者：
Baurand, A;Eckly, A;Gachet, C
在本研究中，我们研究了P2 Y（1）和P2 Y（12）受体与绿色荧光蛋白融合的血小板或星形细胞瘤细胞在激动剂诱导刺激后的脱敏和运输。在血小板和转染细胞中，暴露于10 μ M ADP导致P2Y（1）受体驱动的钙信号脱敏，而P2Y（12）受体介导的cAMP形成抑制不受影响。ADP刺激的血小板的质膜也保留了P2Y（12）活性。激动剂诱导的P2Y（1）受体脱敏伴随着其在血小板和转染细胞中的内化。相反，尽管相当一部分P2Y（12）受体被迅速和瞬时内化，但大多数P2Y（12）受体仍保留在质膜上。激活的P2Y（1）受体通过网格蛋白依赖性途径在细胞和血小板中内化，而P2Y（12）受体似乎使用独特的、不依赖网格蛋白的途径。总之，这些数据表明P2Y（1）和P2Y（12）受体在活化时受到差异调节。Gi蛋白偶联的P2Y（12）受体依赖性反应的脱敏的不存在可能代表了保留否则无反应的血小板的止血性质的机制。
In the present study, we investigated the desensitization and trafficking of the P2Y(1) and P2Y(12) receptors after agonist-induced stimulation of platelets or astrocytoma cells transfected with the P2Y(1) or P2Y(12) receptors fused to green fluorescent protein. In platelets and in transfected cells, exposure to 10 muM ADP caused desensitization of the P2Y(1) receptor-driven calcium signal, whereas the P2Y(12) receptor-mediated inhibition of cAMP formation was not affected. Plasma membranes from ADP-stimulated platelets also retained P2Y(12) activity. Agonist-induced P2Y(1) receptor desensitization was accompanied by its internalization in platelets and transfected cells. In contrast, although a substantial fraction of P2Y(12) receptors was rapidly and transiently internalized, most of the P2Y(12) receptors remained at the plasma membrane. Activated P2Y(1) receptors were internalized through a clathrin-dependent pathway in cells and platelets, whereas the P2Y(12) receptors seemed to use a distinct, clathrin-independent pathway. Together, these data indicate that the P2Y(1) and P2Y(12) receptors are differentially regulated upon activation. The absence of desensitization of the Gi protein-coupled P2Y(12) receptor-dependent responses could represent a mechanism to preserve the hemostatic properties of otherwise unresponsive platelets.