Figure 5

Neurexin and synaptophysin levels fluctuate over the course of minutes at axo-dendritic contact sites and neuroligin induced developing synapses. (A) Image of an axon co-expressing synaptophysin-GFP (green) and neurexin-tdTomato (red) and contacting the somato-dendritic region of a neuron expressing RFP670 (blue). White box corresponds to contact region represented by kymographs in (B). (B) Individual kymographs of an axon expressing synaptophysin-GFP (top) and neurexin-tdTomato (middle) that contacts a dendrite expressing RFP670 (bottom). Levels of both neurexin and synaptophysin fluctuate over the course of minutes to hours at sites that contact somato-dendritic regions of the adjacent neuron (arrows, top), including the formation (white box) and disappearance (white arrowhead) of co-clusters. (C) Kymographs of an axon expressing neurexin-GFP (left) and synaptophysin-RFP (right) contacting a neuroligin-expressing HEK293 cell. The amount of neurexin and synaptophysin at co-clustered sites (arrow, bottom) fluctuates extensively over hours and even within minutes (white arrowheads). Scale bars (A, B) = 10 μm, scale bar (C) = 5 μm.