Numerous functions have been ascribed to the cystic fibrosis transmembrane conductance regulator (CFTR) and all of them rely on the proper trafficking of this protein into the apical plasma membrane. Our understanding is based on the finding that the most common mutation, Δ-F508 CFTR, remains in the endoplasmic reticulum and is degraded. In contrast, drug or temperature rescue allows mutant Δ-F508 CFTR to become fully glycosylated and traffic to the membrane. We will assess the impact of other treatments on mutant CFTR by making use of lipid rafts in which we observe migration of mature CFTR, endogenous or corrected, to a lower buoyant density in a sucrose gradient. In addition, we will create and evaluate antibodies that detect corrected Δ-F508 at the cell surface. We will identify accessory proteins that participate in this process so that we can gain insight into therapies that can be targeted to advance CFTR from within the cell to its functional location.