Figure 6. Puncta of PSD95-RFP and synaptophysin-GFP assemble and disassemble with similar parameters but independently at shared sites.

A. Examples of synaptophysin-GFP (green), PSD95-RFP (red), and colocalization (either yellow or adjacent green and red) before (Pre), 10 min, and 30 min after brief application of saline (control). The arrows indicate examples of PSD95-RFP puncta that were present in the pretest, disassembled at 10 min, and reassembled at 30 min, and the asterisk indicates one that moved. Scale bar, 10 µm. B. Average number of PSD95-RFP puncta that were present only in the pretest (A), 10 min (B), 30 min (C), and various combinations (AB, AC, etc.), compared to results of a model like the one for synaptophysin-GFP shown in Fig. 4A. The number of puncta in the field has been normalized to the number on the pretest in each experiment (average pretest value  = 114, n = 24). C. Average number of sites with only synaptophysin in the pretest (A), PSD95 in the pretest (B), synaptophysin in the posttest (C), PSD95 in the posttest (D), and various combinations (AB, AC, etc.), compared to results of the model illustrated in D. Data for the 10 min and 30 min posttests were similar, and have been pooled. The number of sites of each type in the field has been normalized to the sum of synaptophysin-GFP and PSD95-RFP puncta on the pretest in each experiment (average pretest values  = 48 synaptophysin and 51 PSD95, n = 11). D. Cartoon of the model used to fit the data in C. Puncta of synaptophysin and PSD95 assemble and disassemble independently with the same parameters at shared sites, which are more stable than the puncta themselves.