(A-F) Representative confocal images of boutons at NMJ4 of larvae expressing Gbb-HA via D42Gal4 in otherwise wild-type (A,B), cmpyΔ8 homozygous (C,D) and Cmpy overexpression (E,F) backgrounds stained with anti-HA (Gbb-HA) and anti-HRP (neuronal membrane). (G) Quantification of the Gbb-HA/HRP ratio for the indicated genotypes indicates that presynaptic levels of Gbb-HA are reduced two-fold in cmpy nulls (n > 25 NMJs). (H) Quantification of the Gbb-HA/HRP ratio for the indicated genotypes indicates that presynaptic levels of Gbb-HA are increased 2.7-fold by Cmpy overexpression (n > 12 NMJs). (I-N) Representative confocal images of boutons at NMJ4 of wild-type (I,J), cmpyΔ8 homozygous (K,L) and D42Gal4, UASCmpy-Venus (M,N) larvae stained with anti-Gbb (Gbb) and anti-Fas2 (neuronal membrane). (O) Quantification of mean pixel intensity of Gbb inside the presynaptic terminal defined by Fas2 for the indicated genotypes indicates that presynaptic levels of Gbb are decreased more than two-fold in cmpy nulls (n = 8 NMJs). (P) Quantification of mean pixel intensity of Gbb inside the presynaptic terminal defined by Fas2 for the indicated genotypes indicates that presynaptic levels of Gbb are increased 1.3-fold by Cmpy overexpression (n = 8 NMJs). Scale bars are 2 μm. ** p<0.01 and *** p<0.001; error bars are SEM.