CFTR and cystic fibrosis: In these studies, aside from the difference in baseline currents that recapitulated prior experiments, we observed a compensatory increase of ATP-dependent Cl– transport with truncated CFTR (G542X rats) compared to wild type (Supplementary Figure 1, stimulatory protocol), which has also been seen in CFTR knockout rats and CF patients (Tuggle et al., 2014).