Neurons expressing M18Y473D are not impaired at SV docking. Autaptic munc18-1 null hippocampal neurons expressing M18Y473D or M18WT as controls were analysed with electron microscopy on cryofixed samples (I) The active zone (AZ) length is similar (M18WT: 740.2 ± 29.7 nm; M18Y473D: 771.4 ± 28.1 nm, multilevel analysis, p = 0.871).(G-J) M18WT : N=3 independent cultures, n=159 synapses; M18Y473D: N=3 independent cultures, n=156 synapses. 