Figure 3.

Single-molecule imaging in live cells. TMR-labeled cAMP receptors of Dictyostelium discoideum were imaged on both the basal (a) and apical surfaces (b). Scale bars, 3 μm. (c) Diffusion coefficients of cAMP receptors at the apical and basal surfaces of the cell. Molecules surviving for >15 frames (54 molecules/cell for the basal surface and 30 molecules/cell for the apical surface on average) were used for the analysis. Molecules from the same amoeba cell were used to get a single diffusion-coefficient value for either the basal surface or the apical surface. The data presented are the averages of 13 cells for the basal surface, and 11 cells for the apical surface. The oil-immersion objective was used for the experiments, and the exposure time was 50 ms.