FIGURE 2.

Single molecule quantification of SEP-MORs transported in recycling vesicles. A, representative maximum fluorescence intensity measurement of a single EGFP. B, single EGFP molecules were adsorbed and imaged prior to recycling experiments, utilizing identical TIR-FM imaging conditions. Isolated EGFPs were identified by their characteristic blinking and single photobleaching step; maximum intensities were binned, obtaining a mean intensity of 319.6 ± 5.8 S.E. per single EGFP molecule (n = 906). C, maximum fluorescence intensity of single recycling events was measured in striatal neurons and HEK293 cells with a mean intensity of 5696 and 7489, respectively (n = 70 for neurons, and n = 66 for HEK293 cells). D, number of SEP-MORs/vesicle ranged from ∼8 to ∼55, with an average number of ∼18 receptors in striatal neurons and an average of ∼23 receptors in HEK293.