Figure 3: Postsynaptic overexpression of dLRRK increases pool of readily releasable vesicles.

(a) Failure analysis of dLRRK OE larvae. Distribution of EJC amplitudes and mEJC amplitudes (inset) recorded under low external Ca²⁺ concentrations (0.25 mM) for control (G14-Gal4/+, n=2,572 EJCs and 1,784 mEJCs (left), and larvae overexpressing dLRRK in the muscle (G14-Gal4/UAS-dLRRK, n=3,024 EJCs and 1,828 mEJCs) (middle). Black bars indicate events that were considered as failures. (control n=409, dLRRK OE n=152). Quantification of QC (right). **P<0.001, Student’s t-test. Error bars are s.e.m. (b) Representative (continuous recording) of EJC amplitudes in control (MHC-Gal4/+) larvae elicited at 0.2 Hz at the indicated Ca²⁺ concentrations. (c) Representative parabolic variance–mean plots for control (MHC-Gal4/+) (solid) and overexpression of dLRRK (UAS-dLRRK/+; MHC-GAL4/+) in muscle (dotted). (d,e) Quantal parameters for the number of ready-release vesicles (d) and the probability of vesicle release (e) for overexpression of dLRRK (UAS-dLRRK/+; MHC-Gal4/+) and control (MHC-Gal4/+). n=7 and 5. (f,g) Mean cumulative EJC plot with back extrapolation of linear fit from the last ten stimuli to time zero (f) and bar graph shows the relative size of RRP (g) for overexpression of control (MHC-Gal4/+) and dLRRK OE (UAS-dLRRK/+; MHC-Gal4/+). n=8 and 10. Recordings performed in 3 mM Ca²⁺ HL3 for 60 Hz, 30 stimuli. Error bars represent s.e.m. *P<0.05 and **P<0.01. See Supplementary Table 1.