A method for imaging single molecules at the plasma membrane of live cells within tissue slices

Recent advances in light microscopy allow individual biological macromolecules to be visualized in the plasma membrane and cytosol of live cells with nanometer precision and similar to 10-ms time resolution. This allows new discoveries to be made because the location and kinetics of molecular interactions can be directly observed in situ without the inherent averaging of bulk measurements. To date, the majority of single-molecule imaging studies have been performed in either unicellular organisms or cultured, and often chemically fixed, mammalian cell lines. However, primary cell cultures and cell lines derived from multicellular organisms might exhibit different properties from cells in their native tissue environment, in particular regarding the structure and organization of the plasma membrane. Here, we describe a simple approach to image, localize, and track single fluorescently tagged membrane proteins in freshly prepared live tissue slices and demonstrate how this method can give information about the movement and localization of a G protein-coupled receptor in cardiac tissue slices. In principle, this experimental approach can be used to image the dynamics of single molecules at the plasma membrane of many different soft tissue samples and may be combined with other experimental techniques.

Automated summary

Recent advances in light microscopy have enabled the visualization of individual biological macromolecules in live cells with nanometer precision and high time resolution. This allows for direct observation of molecular interactions without bulk averaging, leading to new discoveries. While most single-molecule imaging studies have been done in unicellular organisms or cultured mammalian cell lines, there is potential to apply this approach to studying dynamics in different tissue samples.