SDN-1ICD recruits N-AChR to GABA synapses. (A) Structure of the chimeric protein containing the NLG-1 ecto- and transmembrane (TM) domains and the SDN-1ICD. mNG tag was inserted immediately after the signal peptide (SP). The PDZ-binding motif of SDN-1 is shown in blue. (B) Confocal detection of mNG-NLG-1ECD/SDN-1ICD expression driven by the muscle-specific promoter Pmyo-3 and of the presynaptic marker CLA-1-BFP driven by the GABAergic neuron-specific promoter Punc-47. (C) Confocal detection and fluorescent profiles of ACR-16-wrmScarlet and cholinergic active zone marker CLA-1-BFP. NLG-1ECD/SDN-1ICD was expressed under the muscle-specific promoter Pmyo-3 in sdn-1(0) mutant animals. (D) Pearson’s correlation coefficient between N-AChRs (ACR-16-wrmScarlet) and cholinergic boutons. (E) Confocal detection and fluorescent profiles of L-AChRs (UNC-29-RFP) and mNG-NLG-1ECD/SDN-1ICD driven by the muscle-specific promoter Pmyo-3 in sdn-1(0) mutants. (F) Pearson’s correlation coefficient between the chimera and N-AChRs (ACR-16-wrmScarlet) or L-AChRs (UNC-29-RFP) in sdn-1(0) mutants. (G) Quantification of UNC-29-RFP in control, sdn-1(0), and sdn-1(0) animals expressing the chimera specifically in muscle. Scale bars, 10 µm.