Figure 6.

Serine protease trypsin can activate ENaC to produce Na+ current in Xenopus oocytes. The three rat ENaC subunits and one of water, WT, or mutant TMPRSS3 were co-injected into Xenopus oocytes. After injection, the oocytes were treated with trypsin and then Na+ currents were recorded. (A) After trypsin treatment, the ENaC was significant activated, producing Na+ currents in the water (H₂O) group. (B) In the TMPRSS3WT group, whether there was a trypsin treatment or not did not affect the ENaC activation and the Na+ currents. (C–F) All of the four missense mutation groups were very similar to the water group, and ENaC could be activated, increasing the Na+ currents. (G) In the quantitative analysis, 10 Xenopus oocytes were treated by trypsin and measured by ENaC-mediated INa in each group. (n ≥10).