Electrophysiological characteristics of the Ca2+-activated Cl- channel family of anion transport proteins

1. A protein isolated from the bovine tracheal epithelium behaves as a Ca2-activated Cl- channel (CaCC) when incorporated into planar lipid bilayers. 2. An antibody raised against this protein was used to screen a cDNA expres sion library and resulted in the isolation of a cDNA clone that exhibited n early identical electrophysiological characteristics to the isolated endoge nous protein when expressed. 3. Recent cloning of several related proteins has revealed that the cloned bovine CaCC is one of a large and growing family. All new family members so far examined are associated with the appearance of a novel Ca2+-mediated C l- conductance when heterologously expressed. 4. This new group of proteins may underlie the Ca2+-mediated Cl- conductanc e upregulated in the cystic fibrosis (CF) knockout mouse and thought to be responsible for the escape from the significant airway pathology associated with CF.