Figure 7

Trans-synaptic signaling does not attract synaptic vesicle or active zone proteins. (A) Schematics of HEK293 cell contact with an axon. Analysis was done on all STVs with initial positions either outside the contact area (gray area, left, center) or directly adjacent to the contact region (gray area, right). (B-D) Histograms of the net movement of STVs towards (positive) or away from (negative) contacts with HEK293 cells expressing either neuroligin-1 + HcRed (B, D) or HcRed only (C). STV movement was not biased towards sites of neurexin-neuroligin signaling, for either all STVs or only STVs adjacent to the contact. (E, F) Scatter plot of the number of STVs moving towards versus away from contacts with cells expressing neuroligin-1 + HcRed (blue circles) or HcRed only (red squares). Each small point represents the ratio for one axon, with larger points representing additional axons with the identical ratio. These ratios were approximately the same for axons that contact cells expressing neuroligin-1 or HcRed (black line = unity ratio line). (G) Similar to STVs, PTVs were not attracted to sites of neuroligin-1 contact. (B-D, G) Red arrows = mean.