Fig. 5. Cytosolic fragments are derived from multiple peptide domains. Membrane pellet and supernatant fractions were collected from CFTR degradation reactions carried out for 2 hours in the presence of 100 µM MG132. Samples were immunoprecipitated by N-terminal, C-terminal and R-domain specific antisera and quantified by scintillation counting as in Fig. 5. Data are expressed as the percentage of total radioactive counts in pellet and supernatant fractions that remained associated with indicated epitopes.