Recombinant human Cathepsin S protein (Active)

Supplementary information

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

Cathepsin S sometimes referred to as CTSS is a cysteine protease enzyme weighing about 24-29 kDa part of the papain family. It occurs mainly in lysosomes and is expressed in a variety of cells including antigen-presenting cells like macrophages dendritic cells and B lymphocytes. Cathepsin S functions to cleave proteins at lysines playing a central role in protein degradation and antigen processing. It distinguishes itself from other cathepsins by maintaining activity in an alkaline environment and is essential for the processing of invariant chain (Ii) in MHC class II molecules.

Biological function summary

Cathepsin S participates in immune system modulation and matrix degradation. It stands out in its role in the immune response cleaving antigenic proteins for presentation by MHC class II therefore influencing T-cell activation. Although synonymous with lysosomal activity it also operates extracellularly contributing to tissue remodeling and inflammation. Cathepsin S is not part of a larger complex but interacts with MHC class II impacting antigen presentation.

Pathways

This protease is critical in the immune system and extracellular matrix degradation pathways. In the context of the immune pathway CTSS interacts with other proteases such as Cathepsin L and Cathepsin B to perform antigen trimming and processing. Moreover CTSS supports the activation of T lymphocytes by ensuring the correct presentation of peptide fragments on MHC class II molecules. In matrix degradation CTSS indirectly influences collagen breakdown and interaction with other matrix metalloproteinases.

Cathepsin S is associated with autoimmune diseases like rheumatoid arthritis where it contributes to tissue inflammation and joint damage. It also relates to atherosclerosis promoting instability in atherosclerotic plaques which could result in heart disease. In rheumatoid arthritis interactions with cytokines like TNF-alpha amplify inflammatory responses while in atherosclerosis CTSS links with other proteases to degrade extracellular matrix components leading to vulnerable lesions.