A-D Representative whole-cell current traces recorded in an oocyte expressing murine ENaC alone (ENaC; A) or in combination with murine wild-type Prss8 (ENaC + Prss8-WT; B), zymogen-locked Prss8-R44Q (ENaC + Prss8-R44Q; C), or catalytically inactive Prss8-S238A (ENaC + Prss8-S238A; D). Presence of amiloride (Ami, 2 μM) or chymotrypsin (Chym, 2 μg/ml) in the bath solution is indicated by corresponding black or grey bars, respectively.
E Summary of data obtained in similar experiments as in A-D. Individual and mean ± SEM values of ΔIami before (−) and after (+) application of chymotrypsin. Measurements performed in the same oocyte are connected by a line (n=32 from 4 different batches of oocytes). ‡, p<0.001; †, p<0.01; n.s. not significant; Student’s t test.
F Summary of the data shown in E normalized as relative stimulatory effect of chymotrypsin on ΔIami, i.e. the ratio of ΔIami after chymotrypsin to ΔIami before chymotrypsin. Thus, a ratio of one (dotted line) indicates the absence of a stimulatory effect of chymotrypsin on ENaC. Individual and mean ± SEM values are shown. ‡, p<0.001; n.s. not significant; one-way ANOVA with Bonferroni post hoc test.