Probing nanoscale self-assembly of nonfluorescent small molecules inside live mammalian cells.
Like cellular proteins that form fibrillar nanostructures, small hydrogelator molecules self-assemble in water to generate molecular nanofibers. In contrast to the well-defined (dys)functions of endogenous protein filaments, the fate of intracellular assembly of small molecules remains largely unknown. Here we demonstrate the imaging of enzyme-triggered self-assembly of nonfluorescent small molecules by doping the molecular assemblies with a fluorescent hydrogelator. The cell fractionation experiments, fluorescent imaging, and electron microscopy indicate that the hydrogelators self-assemble and localize to the endoplasmic reticulum (ER) and are likely processed via the cellular secretory pathway (i.e., ER-Golgi-lysosomes/secretion). This work, as the first example of the use of correlative light and electron microscopy for probing the self-assembly of nonfluorescent small molecules inside live mammalian cells, not only establishes a general strategy to provide the spatiotemporal profile of the assemblies of small molecules inside cells but may lead to a new paradigm for regulating cellular functions based on the interactions between the assemblies of small molecules (e.g., molecular nanofibers) and subcellular organelles.
Department of Chemistry and ‡Department of Biology, Brandeis University , 415 South Street, Waltham, Massachusetts 02454, United States.
Yuan
Y
Gao
Cristina
C
Berciu
Yi
Y
Kuang
Junfeng
J
Shi
Daniela
D
Nicastro
Bing
B
Xu
D006367:HeLa Cells; D006801:Humans; D046529:Microscopy, Electron, Transmission; D015335:Molecular Probes; D036103:Nanotechnology
D015335:Molecular Probes