Related Experiment Video
Updated: Jul 18, 2026

Analysis of Protein Folding, Transport, and Degradation in Living Cells by Radioactive Pulse Chase
Published on: February 12, 2019
Folding, activity and targeting of mutated human cathepsin D that cannot be processed into the double-chain form
Carlo Follo1, Roberta Castino, Giuseppina Nicotra
1Laboratory of Molecular Pathology, Dipartimento di Scienze Mediche, Università del Piemonte Orientale A. Avogadro, via Solaroli 17, 28100 Novara, Italy.
Abstract:
The precursor of human cathepsin D (CD) is converted into the single-chain and the double-chain active polypeptides by subsequent proteolysis reactions taking place in the endosomal-lysosomal compartment and involving specific aminoacid sequences. We have mutagenized the region of aminoacids (comprising the beta-hairpin loop) involved in the latter proteolytic maturation step and generated a mutant CD that cannot be converted into the mature double-chain form. This mutant CD expressed in rodent cells reaches the lysosome and is stable as single-chain polypeptide, bears high-mannose type sugars, binds to pepstatin A and is enzymatically active, indicating that it is correctly folded. The present work provides new insights on the aminoacid region involved in the terminal processing of human CD and on the function of the processing beta-hairpin loop.
Related Concept Videos
Export of Misfolded Proteins out of the ER
Molecular Chaperones and Protein Folding
The...
Protein Folding
Protein Structure Is Critical to Its Biological Function
Proteins perform a wide range of biological functions such as catalyzing chemical reactions, providing...
Protein Folding
Amyloid Fibrils
Amyloid deposits were observed as early as 1639 in the liver and the spleen. In 1854, Rudolph Virchow performed iodine staining, normally used to...
Protein Folding Quality Check in the RER

