Synaptic vesicle connectors for vesicles within 250 nm from the AZ. Connectivity increased both in WT and RIM1a KO under MG132 treatment. (A) Fraction of connected vesicles. (B) Fraction of connected vesicles versus distance to the AZ. (C) Mean number of connectors per vesicle. (D) Fraction of vesicles as a function of tethering and connectivity. C shows mean values and SEMs (error bars). A, B, and D show number of occurrences (consequently no error bars are displayed). Confidence values: *, P < 0.05; **, P < 0.01; ***, P < 0.001. The numbers of animals, synapses, vesicles, and connectors analyzed for each category are shown in Table S1. SV, synaptic vesicle.