LIN-2 is concentrated at GABA synapses in animals lacking SDN-1 PDZ-binding motif. (A) Confocal detection and quantification of mNG-SDN-1 fluorescence levels in control (mNG-sdn-1) and mNG-sdn-1(ΔEYFA) animals. (B) Confocal detection and fluorescence profiles of RFP-LIN-2A, expressed under the muscle-specific Pmyo-3 promoter, and GABAergic presynaptic active zones, using the CLA-1-BFP marker under Punc-47 promoter, in control and sdn-1(ΔEYFA) animals. (C) Pearson’s correlation coefficient between RFP-LIN-2A and GABAergic active zones in control and sdn-1(ΔEYFA) animals. (D) Fluorescence levels of RFP-LIN-2A along the dorsal nerve cord (left) or at GABA synapses (right) in control and sdn-1(ΔEYFA) animals. Total fluorescence (left panel) was measured as for other figures. To measure fluorescence specifically at GABA synapses, RFP-LIN-2A fluorescence was measured within GABA regions, which were defined by the presence of the Punc-47::cla-1-bfp marker. Scale bars, 10 µm.