Increased levels of ectopically expressed C1D(EGFP) in the presence of the proteasome-specific inhibitor MG115. Cells were transfected with pcDNA3-C1D(EGFP). The culture was split at 8 hours post transfection, and incubation was continued (16 hours) without (-) or with (+)10 μM of the proteasome-specific inhibitor MG115. Lysates of cell pellets with identical cell numbers were submitted side by side to 12% SDS-polyacrylamide gelelectrophoresis. Parallel lanes were either stained (left) or electroblotted to nitrocellulose which was immuno-stained by means of the monospecific C1D antibody , and 125Iodine-labelled anti rabbit Ig. The autoradiograph of the blot is shown together with the positions of prestained marker proteins. The main autoradiographic signal corresponds with the molecular mass of the C1D(EGFP) fusion protein (43 kDa).