PLASMA-MEMBRANE RECYCLING IN CFTR-EXPRESSING CHO CELLS

The hypothesis that the cystic fibrosis transmembrane conductance regu lator (CFTR) participates in plasma membrane recycling was tested expe rimentally. Using CHO cells, we determined the effects of CFTR express ion and of elevated intracellular cAMP on exocytosis, measured as the incorporation into the plasma membrane of endosomes pre-labelled with biotinylated wheat-germ agglutinin (WGA). CFTR expression was without effect on the rate of exocytosis. Furthermore, cAMP did not affect end osomal recycling to the plasma membrane in either CFTR-expressing or c ontrol cells. These findings suggest that CFTR is not involved in regu lating plasma membrane recycling in all cells.