Selective Labeling of Phosphatidylcholine to Track Their Translocation Between Organelles in Living Cells.

Phosphatidylcholine (PC) is a major phospholipid that forms biological membranes in eukaryotes. PC is mainly synthesized in the endoplasmic reticulum (ER) and Golgi apparatus and then transported to other organelle membranes via multiple mechanisms. Such interorganelle lipid transport is thought to play an important role in the maintenance of cell morphology, organelle functions, and homeostasis, though the details of this process have not yet been well investigated. This chapter describes a technology for the selective labeling and fluorescence imaging of PC in target organelles. This approach involves the metabolic incorporation of azidocholine, followed by a spatially restricted bioorthogonal click reaction that enables the visualization and quantitative analysis of interorganelle PC transport in live cells using confocal microscopy.