E-64, cysteine protease inhibitor

Supplementary information

This supplementary information is collated from multiple sources and compiled automatically.

Cathepsin B Cathepsin L and Cathepsin S are lysosomal cysteine proteases that function in the degradation of proteins. Cathepsin B also known as APP secretase has a molecular weight of about 25-30 kDa. Cathepsin L also referred to as MEP weighs approximately 24-29 kDa. Meanwhile Cathepsin S possesses a mass of around 24 kDa. These cathepsins express in various cell types including macrophages neutrophils and epithelial cells as well as in tissues such as the liver kidney and spleen. The expression of these enzymes allows for the processing and breakdown of intracellular and extracellular proteins.

Biological function summary

These cathepsins play key roles in protein catabolism and are significant contributors to cellular homeostasis. While not typically part of protein complexes these proteases do interact with other molecular components to achieve protein turnover in lysosomal compartments. They participate in processes like antigen presentation and the maintenance of the extracellular matrix. Their activity continues to regulate immune responses and cellular remodeling by cleaving specific peptide substrates.

Pathways

Cathepsins B L and S engage prominently in pathways such as the immune response pathway and apoptosis. During immune response they influence the degradation of antigenic proteins for presentation to the immune system. In apoptosis these proteases modulate the proteolytic cascade that breaks down cellular components linking them to proteins like caspases which are central to the cell death pathway. Their involvement in these pathways highlights their critical regulatory roles in cellular processes.

Dysregulation of Cathepsin B L and S relates to conditions like cancer and neurodegenerative diseases. In cancer these proteases contribute to tumor invasion and metastasis through their action on the extracellular matrix where they may interact with proteins like matrix metalloproteinases. In neurodegenerative diseases such as Alzheimer's Cathepsin B has implications due to its role in amyloid precursor protein processing. The altered activity of these cathepsins may enhance pathological proteolysis therefore linking them to the progression of these disorders.