An exclusion zone model reveals similar nanoscale distribution of Cav2.1 in AZs on Kv3.1b+ and mGluR1α+ INs
(A) An AZ on a Kv3.1b+ dendrite is shown (demarcated with orange line). Centers of experimentally determined Munc13-1 clusters (small black open circles) are surrounded by exclusion zones of 40 nm radius (EZ 40nm, large circles), the original positions of the Cav2.1 gold particles are shown with orange dots, and the locations of the same number of randomly placed particles generated by the exclusion zone model (EZM) are shown by the purple dots.
(B) Ratios of mean NNDs calculated from experimental and an EZM-generated Cav2.1 pattern are plotted for 5 different exclusion zone radii (n = 74 AZs, 50 random simulations per AZ). Corresponding data (open circles) and their boxplot summary are colored identically. Random patterns at 60, 55, and 30 nm EZ radii are significantly different from the data (p < 0.01, Friedman test followed by WSR test with HBC).
(C) Same as (A) but for an AZ contacting an mGluR1a+ dendrite.
(D) Same as (B) but showing ratios of mean NNDs from AZs contacting mGluR1a+ dendrites (n = 59 AZs). Random patterns at 60, 55, and 30 nm EZ radii are significantly different form the data (p < 0.003, Friedman test followed by WSR test with HBC). Horizontal lines in the box plots: 25th, 50th, and 75th percentiles, rectangle: mean, whiskers: SD.