Metabolic Labeling of Phosphatidylethanolamine Lipids in Cells Using Clickable Ethanolamine Analogs

Phosphatidylethanolamine (PE) is the second most abundant phospholipid in mammalian cells. The cone-shaped structure of PE positions this lipid to act as a cornerstone of signaling events, such as those involving protein-protein and lipid-protein interactions, as it has been shown to promote conformational changes in both protein and lipid-based membrane structures. Despite this importance, chemical tools to interrogate the biological activity and trafficking of PE lipids are limited. Herein, we report the development of ethanolamine probes functionalized with clickable tags that are capable of infiltrating native cellular pathways and subsequently producing labeled PE lipids. Derivatization of click-tagged PE products enabled fluorescence microscopy imaging of these lipids in cells. Interrogation of the efficacy of these probes for biological incorporation was conducted using mass spectrometry and thin-layer chromatography analysis to identify various species of tagged PE molecules. This approach provides an invaluable step toward metabolic labeling strategies that will aid in the tracking of PE biosynthesis and trafficking pathways in cells.