Single-Molecule Microscopy - From membranes to fish

Many vital cellular signaling pathways lead through components that are at least transiently localized at the plasma membrane. As such the interaction of G-protein-coupled receptors with G proteins is a key event in transmembrane signal transduction that leads to vital decision-making by the cell. Here, we applied single-molecule epifluorescence and super-resolution microscopy to study the mobility and localization of membrane components in mammalian cells. We found that the mobility and localization of components is closely linked with their functional state. Our findings led us to the hypothesis that functional nanometric domains exist in the plasma membrane, which locally restrict the activation signal, and in turn, lead to faithful and efficient signaling.