The present invention provides a method to label phospholipids in vivo based on the metabolic incorporation of an alkynyl- or azido-labeled metabolic precursor into phospholipids. The resulting phospholipids have alkynyl or azido moieties, which, upon reaction with a labeled azide or alkyne, respectively, form labeled compounds that can be visualized using optical or electron microscopy with high sensitivity and spatial resolution in cells or tissue. The present method provides a valuable tool for imaging phospholipid synthesis, turnover and subcellular localization in cultured cells as well as in animals.
