Vesicle Docking Is a Key Target of Local PI(4,5)P2 Metabolism in the Secretory Pathway of INS-1 Cells.
Vesicle Docking Is a Key Target of Local PI(4,5)P2 Metabolism in the Secretory Pathway of INS-1 Cells.
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囊泡对接是 INS-1 细胞分泌途径中局部 PI(4,5)P2 代谢的关键目标。
DOI：
10.1016/j.celrep.2017.07.041
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发表时间：
2017
期刊：
影响因子：
8.8
通讯作者：
Lou,Xuelin
中科院分区：
文献类型：
--
作者：
Ji,Chen;Fan,Fan;Lou,Xuelin
磷脂酰肌醇 4,5-二磷酸 (PI(4,5)P2) 信号传导在活细胞中是短暂的且空间受限。这种信号传导模式如何调节递质释放和激素分泌尚未得到解决。我们设计了一种光遗传学方法来控制胰岛素分泌细胞中时间和空间上的 PI(4,5)P2 水平。将此方法与全内反射荧光显微镜相结合，我们检查了单个囊泡运输步骤。与长期 PI(4,5)P2 扰动不同，质膜 (PM) 中快速且全细胞范围的 PI(4,5)P2 减少会强烈抑制分泌和细胞内 Ca2+ 浓度 ([Ca2+]i) 反应，但不会抑制 sytaxin1a 聚类。有趣的是，在囊泡对接位点选择性地局部 PI(4,5)P2 还原会导致囊泡从 PM 上显着脱离，而不影响 [Ca2+]i。这些结果强调了局部 PI(4,5)P2 在囊泡束缚和对接中的关键作用，与其在启动和融合中的作用相协调。因此，不同的时空 PI(4,5)P2 信号传导调节囊泡运输的不同步骤，并且囊泡对接可能是体内局部 PI(4,5)P2 信号传导的关键目标。
Phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) signaling is transient and spatially confined in live cells. How this pattern of signaling regulates transmitter release and hormone secretion has not been addressed. We devised an optogenetic approach to control PI(4,5)P2levels in time and space in insulin-secreting cells. Combining this approach with total internal reflection fluorescence microscopy, we examined individual vesicle-trafficking steps. Unlike long-term PI(4,5)P2perturbations, rapid and cell-wide PI(4,5)P2reduction in the plasma membrane (PM) strongly inhibits secretion and intracellular Ca2+concentration ([Ca2+]i) responses, but not sytaxin1a clustering. Interestingly, local PI(4,5)P2reduction selectively at vesicle docking sites causes remarkable vesicle undocking from the PM without affecting [Ca2+]i. These results highlight a key role of local PI(4,5)P2in vesicle tethering and docking, coordinated with its role in priming and fusion. Thus, different spatiotemporal PI(4,5)P2signaling regulates distinct steps of vesicle trafficking, and vesicle docking may be a key target of local PI(4,5)P2signaling in vivo.