Figure 1. The X, C1, and C2B Domains in UNC-13L Inhibit Tonic Release.

Miniature EPSCs were recorded from the body wall muscle of adult worms in a 0 mM Ca²⁺ solution.

(A) Cartoon depicting the domain structure of UNC-13L.

(B) Representative mIPSC traces from the indicated genotypes.

(C and D) Quantification of the frequency (C) and amplitude (D) of the mIPSCs from the same genotypes as in (B).

(E) Representative mEPSC traces from the indicated genotypes.

(F and G) Average of the frequency (F) and amplitude (G) of the mEPSCs from the same genotypes as in (E).

(H) Sequence alignment of the C1 and C2B domains between worm unc-13 and rat Munc13-1. Identical residues are highlighted (blue). The histidine (H) that is essential for DAG binding in the C1 domain and the five aspartates (D1-D5) that bind Ca²⁺ in the C2B domain are indicated with stars.

(I) Representative mIPSC traces from the indicated genotypes.

(J and K) Quantification of the frequency (J) and amplitude (K) of the mIPSCs from the same genotypes as in (I).

Data are presented as box-and-whisker plots, with both the median (line) and mean (cross) indicated. ###p < 0.001 compared with the wild type; *p < 0.05, **p < 0.01, ***p < 0.001 compared with UNC-13L rescue; n.s., non-significant compared with UNC-13L rescue; one-way ANOVA test for the data in (D) and (G); oneway ANOVA following Kruskal-Wallis test for the data in (C), (F), (J), and (K). The number of worms analyzed for each genotype is indicated under each box.