CFTR and cystic fibrosis: Recent studies in killfish demonstrate that arsenic induces CFTR ubiquitinylation and degradation.20,21 In human airway epithelial cell culture, arsenic induces an increase in multiubiquitinlyated CFTR, which results in CFTR degradation and reduced CFTR-mediated chloride secretion.22 Together, these reports demonstrate that arsenic impairs CFTR function and support the hypothesis that there is a shared pathobiologic mechanism driving both cystic fibrosis and arsenic-induced lung disease.