Figure 4From: The PEST sequence does not contribute to the stability of the cystic fibrosis transmembrane conductance regulatorTrypsin Sensitivity of CFTR PEST Mutants. Membranes were prepared from COS-1 cells transiently transfected with the cDNA of the various constructs. The membranes were treated with various concentrations (0–1000 μg/ml) of TPCK-treated trypsin. The reactions were stopped by the addition of lima bean trypsin inhibitor. Equivalent amounts of protein were subjected to immunoblot analysis (monoclonal antibody against the A52 tag).Back to article page