Fig. 6

PS1-Syt1 interaction modulates synaptic vesicle trafficking. a Fluorescent images show distribution of the eGFP-synaptophysin (eGFP-Syp) in primary neurons pre-treated for 2 h with scramble and PS1-LNT peptides. Note increased fluorescence intensity in synaptic puncta along the processes. The arrows point to the example region of interests (ROIs) used for the photobleaching experiments; scale bar 15 μm. b Fluorescence recovery after photobleaching (FRAP) experiments demonstrate impaired motion of synaptic vesicle proteins in the PS1-LNT pre-treated neurons. The fluorescent images present 5 μm-diameter ROIs recorded in eGFP-Syp expressing neurons pre-treated for 2 h with scramble or PS1-LNT peptides, and stimulated for with 50 mM KCl. Three ROIs are analyzed for each condition: pre-bleach, immediately after bleach and 10 s after bleach. The adjacent bar graph demonstrates the quantification of the eGFP-Syp fluorescence recovered within 10 s post-bleach. The data are presented as mean + SEM, n = 36. Statistical significance was determined using unpaired Student’s t-test, ***p < 0.001. c Fluorescent images present distribution of the eGFP-tubulin (eGFP-Tub) in primary neurons pre-treated with scramble and PS1-LNT peptides. The arrows point to the ROIs used for the photobleaching experiments; scale bar 15 μm. d Control FRAP experiments demonstrate no alterations in eGFP-tubulin fluorescence recovery after photobleaching in neurons pre-treated for 2 h with PS1-LNT or scramble peptides, and stimulated with 50 mM KCl for 15 min. The fluorescent images present 5 μm-diameter ROIs recorded in eGFP-Tub expressing neurons pre-treated with scramble or PS1-LNT peptides. The data are presented as mean + SEM, n = 19. Statistical significance was determined using unpaired Student’s t-test