Analysis of where and which types of proteinases participate in lysosomal proteinase processing using bafilomycin A1 and Helicobacter pylori Vac A toxin

• Published in: Journal of biochemistry (Tokyo) 1999-04, Vol.125 (4), p.770-779
• Main Authors: Ishidoh, K, Takeda-Ezaki, M, Watanabe, S, Sato, N, Aihara, M, Imagawa, K, Kikuchi, M, Kominami, E
• Format: Article
• Language: English
• Subjects: 3T3 Cells; Amino Acid Sequence; Animals; Anti-Bacterial Agents - pharmacology; Bacterial Proteins - pharmacology; beta-N-Acetylhexosaminidases - metabolism; Cathepsin D - chemistry; Cathepsin D - metabolism; Cathepsins - chemistry; Cathepsins - metabolism; Endopeptidases - metabolism; Enzyme Inhibitors - pharmacology; Enzyme Precursors - chemistry; Enzyme Precursors - metabolism; Helicobacter pylori; Lysosomes - drug effects; Lysosomes - enzymology; Macrolides; Mice; Protease Inhibitors - pharmacology; Protein Processing, Post-Translational - drug effects; Proton-Translocating ATPases - antagonists & inhibitors; Vacuolar Proton-Translocating ATPases; Vacuoles - drug effects; Vacuoles - enzymology
• ISSN: 0021-924X
• DOI: 10.1093/oxfordjournals.jbchem.a022348

Lysosomal proteinases are translated as preproforms, transported through the Golgi apparatus as proforms, and localized in lysosomes as mature forms. In this study, we analyzed which subclass of proteinases participates in the processing of lysosomal proteinases using Bafilomycin A1, a vacuolar ATPase inhibitor. Bafilomycin A1 raises lysosomal pH resulting in the degradation of lysosomal proteinases such as cathepsins B, D, and L. Twenty-four hours after the withdrawal of Bafilomycin A1, NIH3T3 cells possess these proteinases in amounts and activities similar to those in cells cultured in DMEM and 5% BCS. In the presence of various proteinase inhibitors, procathepsin processing is disturbed by E-64-d, resulting in abnormal processing of cathepsins D and L, but not by APMSF, Pepstatin A, or CA-074. In the presence of Helicobacter pylori Vac A toxin, which prevents vesicular transport from late endosomes to lysosomes, the processing of procathepsins B and D occurs, while that of procathepsin L does not. Thus, procathepsins B and D are converted to their mature forms in late endosomes, while procathepsin L is processed to the mature form after its arrival in lysosomes by some cysteine proteinase other than cathepsin B.