SLO-1/BK localization at presynaptic terminals is controlled by CTN-1/α-catulin and DYB-1/dystrobrevin, but not by STN-1/syntrophin. (A) Schematic representation of the anatomical structure of a DA neuron. The DB neurons have an axon and dendrites that extend in the other direction. The unc-129 promoter (~2. 4 kb) drives expression in a subset of DA and DB cholinergic motor neurons. The axon processes with neuromuscular and VD synapses (green) are presynaptic regions, and individual synaptic areas (red) are presynaptic terminals. (B) Representative images of SLO-1::GFP in the axon terminals of DA and DB neurons in wild-type, ctn-1, dyb-1 and stn-1 mutant animals. Arrowheads highlight SLO-1::GFP puncta. The scale bar represents 5 μm. (C) Quantification of SLO-1::GFP puncta in wild-type and mutant animals. The maximum intensity of puncta and the number of puncta within a 10 μm distance were calculated using dotGUI (see Methods). For all the panels, data are presented as the mean ± SEM. *** and n.s. indicate a statically significant difference (multiplicity adjusted p < 0.001) and no significant difference between indicated groups, respectively (One-way ANOVA Dunett’s multiple comparison. wild-type, n = 11; dyb-1, n = 12; stn-1; n = 5). ND, not determined.