Lipids play crucial roles as structural elements, signaling molecules and material transporters in cells. However, the functions and dynamics of lipids within cells remain unclear because of a lack of methods to selectively label lipids in specific organelles and trace their movement by live-cell imaging. We describe here a technology for the selective labeling and fluorescence imaging (microscopic or nanoscopic) of phosphatidylcholine in target organelles. This approach involves the metabolic incorporation of azido-choline, followed by a spatially limited bioorthogonal reaction that enables the visualization and quantitative analysis of interorganelle lipid transport in live cells. More importantly, with live-cell imaging, we obtained direct evidence that the autophagosomal membrane originates from the endoplasmic reticulum. This method is simple and robust and is thus powerful for real-time tracing of interorganelle lipid trafficking.

脂质作为细胞中的结构元件、信号分子和物质转运蛋白发挥着至关重要的作用。然而，由于缺乏选择性标记特定细胞器中脂质并通过活细胞成像追踪其运动的方法，细胞内脂质的功能和动态仍不清楚。我们在这里描述了一种用于目标细胞器中磷脂酰胆碱的选择性标记和荧光成像（微观或纳米）的技术。这种方法涉及叠氮胆碱的代谢掺入，然后进行空间有限的生物正交反应，从而能够对活细胞中细胞器间脂质转运进行可视化和定量分析。更重要的是，通过活细胞成像，我们获得了自噬体膜起源于内质网的直接证据。该方法简单而稳定，因此对于细胞器间脂质运输的实时追踪非常有效。