Cathepsin S His Tag Protein, Human

Cathepsin S (CTSS) is a member of the lysosomal cysteine protease C1 family. It is synthesized as an inactive precursor of 331 amino acids and activated in lysosomes into a mature protease of 217 amino acids through proteolytic removal of its 99-amino acid propeptide. It is primarily expressed in the lysosomes of antigen-presenting cells, such as dendritic cells, B cells, and macrophages.Its core functions are characterized by unique substrate specificity:1) Key Enzyme in Antigen Presentation: It specifically degrades the invariant chain of MHC class II molecules, an essential step for presenting antigenic peptides to CD4⁺ T cells, and also participates in the direct processing and cross-presentation of exogenous antigens.2) Extracellular Matrix Degradation: As an elastase, it can degrade extracellular matrix components over a broad pH range.It holds significant clinical relevance, as dysregulation of its activity is closely associated with various diseases, including arthritis,atherosclerosis,neurological disorders, and chronic obstructive pulmonary disease. It primarily contributes to pathological processes by regulating inflammatory responses, immune reactions, and tissue remodeling, making it a potential therapeutic target for these conditions.