Assessment of the CFTR and ENaC association

Cystic fibrosis (CF) is one of the most common lethal genetic disorders. It results primarily from mutations in the cystic fibrosis transmembrane conductance regulator (cftr) gene. These mutations cause inadequate functioning of CFTR, which in turn leads to the severe disruption of transport function in several epithelia across various organs. Affected organs include the sweat glands, the intestine, and the reproductive system, with the most devastating consequences due to the effects of the disease on airways. Despite aggressive treatment, gradual lung failure is the major life limiting factor in patients with CF. Understanding of the exact manner by which defects in the CFTR lead to lung failure is thus critical. In the CF airway, decreased chloride secretion and increased salt absorption is observed. The decreased chloride secretion appears to be a direct consequence of defective CFTR; however, the increased salt absorption is believed to result from the failure of CFTR to restrict salt absorption through a sodium channel named the epithelial Na+ channel, ENaC. The mechanism by which CFTR modulates the function of ENaC proteins is still obscure and somewhat controversial. In this short review we will focus on recent findings of a possible direct CFTR and ENaC association.