Depletion of SNAP-25, but not synaptobrevins or Munc13–1/2 DKO, leads to changes in cis-Golgi morphology. A, Cortical neuronal cultures from WT, WT treated with TeNT, Munc13–1/2 DKO (M13 DKO), SNAP-25 KO (S25 KO), SNAP-25 KO rescued with eGFP, SNAP-25, Munc18-1 or -3, and Munc18-1/SNAP-25 DKO (M18/S25 DKO) were fixed at DIV 3 and stained with a cis-Golgi marker (GM130) and a dendritic marker (MAP2). B, cis-Golgi (GM130) morphology was analyzed quantitatively using ImageJ software; WT: 17.2 ± 0.75 μm²; WT with TeNT: 19.0 ± 1.93 μm²; Munc13–1/2 DKO: 21.6 ± 1.68 μm²; SNAP-25 KO: 14.0 ± 0.65 μm²; SNAP-25 KO with GFP: 13.7 ± 0.99 μm²; SNAP-25 KO with SNAP-25: 16.2 ± 1.89 μm²; SNAP-25 KO with Munc18-1 (M18-1): 16.5 ± 1.07 μm²; SNAP-25 KO with Munc18-3 (M18-3): 16.1 ± 0.87 μm²; Munc18-1/SNAP-25 DKO: 2.4 ± 0.27 μm². ***p < 0.001 (one-way ANOVA followed by the post hoc Bonferroni's test). C, Soma (MAP2) area was measure quantitatively using ImageJ software; WT: 170.7 ± 6.16 μm²; WT with TeNT: 183.1 ± 10.94 μm²; Munc13–1/2 DKO: 197.0 ± 10.23 μm²; SNAP-25 KO: 125.5 ± 4.70 μm²; SNAP-25 KO with GFP: 132.8 ± 7.50 μm²; SNAP-25 KO with SNAP25: 139.6 ± 10.97 μm²; SNAP-25 KO with Munc18-1: 149.8 ± 7.50 μm²; SNAP-25 KO with Munc18-3: 162.0 ± 7.74 μm²; Munc18-1/SNAP-25 DKO: 73.4 ± 5.61 μm². ***p < 0.001 (one-way ANOVA followed by the post hoc Bonferroni's test). D, cis-Golgi area corrected for the soma area; WT: 1.0 ± 0.03; WT with TeNT: 1.0 ± 0.07; Munc13–1/2 DKO: 1.1 ± 0.06; SNAP-25 KO: 1.1 ± 0.04; SNAP-25 KO with GFP: 1.0 ± 0.05; SNAP-25 KO with SNAP-25: 1.1 ± 0.06; SNAP-25 KO with Munc18-1: 1.1 ± 0.06; SNAP-25 KO with Munc18-3: 1.0 ± 0.04; Munc18-1/SNAP-25 DKO: 0.3 ± 0.03. ***p < 0.001 (one-way ANOVA followed by the post hoc Bonferroni's test). E, cis-Golgi shape was measured quantitatively using ImageJ software; WT: 0.4 ± 0.03; WT with TeNT: 0.4 ± 0.04; Munc13–1/2 DKO: 0.4 ± 0.04; SNAP-25 KO: 0.6 ± 0.02; SNAP-25 KO with GFP: 0.6 ± 0.03; SNAP-25 KO with SNAP-25: 0.4 ± 0.04; SNAP-25 KO with Munc18-1: 0.5 ± 0.04; SNAP-25 KO with Munc18-3: 0.6 ± 0.04; Munc18-1/SNAP-25 DKO: 0.6 ± 0.05. *p < 0.05 (one-way ANOVA followed by the post hoc Bonferroni's test). ***p < 0.001 (one-way ANOVA followed by the post hoc Bonferroni's test). Data are mean ± SEM.