Accumulating α-syn downregulates presynaptic proteins. (A) Confocal images of NMJ immunolabelled with anti-CSP, anti-GFP and anti-HRP. (C) Confocal images of NMJ staining with anti-Synapsin, anti-GFP and anti-HRP. (B) Quantitative analysis of the fluorescence levels of CSP revealed downregulation in the NMJ of nSyb>WT-α-syn-EGFP larvae compared with control; *P = 0.0248; mean ± SEM shown for each genotype (n = 6 flies/genotype). (D) Quantitative analysis of the Synapsin fluorescence levels showed downregulation in the NMJ of nSyb>WT-α-syn-EGFP larvae compared with control; ****P < 0.0001; mean with SEM shown for each genotype (n = 12–13 flies/genotype). Statistical analyses were performed using unpaired two-tailed t-test. Scale bars: 10 µm.