Fig. 3.

Effect of the cysteine protease inhibitor E‐64 on cathepsin D processing. (A) GNPTAB ^−/− cells transfected with the human GNPTAB‐V5/His cDNA construct, and untransfected WT parental HeLa cells were treated with the indicated concentrations of E‐64 for 24 h. Equivalent amount of whole‐cell lysates were loaded for immunoblotting and probed for endogenous cathepsin D. * Indicates a longer exposure of the cathepsin D blot. (B) Immunoblot of endogenous cathepsin B and cathepsin L in whole‐cell lysates of the indicated cell lines, as determined by probing with their respective antibodies. * Indicates a longer exposure of the whole cathepsin L blot.