Asparagusic Golgi\nTrackers

Thiol-mediated uptake\n(TMU) is thought to occur through\ndynamic\ncovalent cascade exchange networks. Here we show that the cascade\naccounting for TMU of asparagusic acid derivatives (AspA) ends in\nthe Golgi apparatus (G) and shifts from disulfide to thioester exchange\nwith palmitoyl transferases as the final exchange partner. As a result,\nAspA combined with pH-sensitive fluoresceins, red-shifted silicon-rhodamines,\nor mechanosensitive flipper probes selectively labels the Golgi apparatus\nin fluorescence microscopy images in living and fixed cells. AspA\nGolgi trackers work without cellular engineering and excel with speed,\nsimplicity, generality, and compatibility with G/ER and cis/trans\ndiscrimination, morphological changes, anterograde vesicular trafficking,\nand superresolution imaging by stimulated emission depletion microscopy.\nGolgi flippers in particular can image membrane order and tension\nin the Golgi and, if desired, at the plasma membrane during TMU.