Cathepsin B, Cathepsin K, Cathepsin L, and Cathepsin S (CTS)

Cathepsin B, Cathepsin K, Cathepsin L, and Cathepsin S are lysosomal cysteine proteases involved in the degradation of intracellular and extracellular proteins. They play essential roles in protein turnover, antigen presentation, apoptosis, and tissue remodeling. Specific members have unique physiological and pathological implications; for example, Cathepsin K is crucial for bone resorption by osteoclasts, Cathepsin S mediates antigen presentation in immune cells, and Cathepsins B and L regulate apoptosis and cancer cell invasion. Therapeutically, they are primary molecular targets for drugs intended to treat cancer, osteoporosis, autoimmune diseases, and fibrosis, but selectivity and safety remain clinical challenges.

Other names

Thiol proteinasecysteine protease BOsteoclast proteinaseMajor excreted protein of kidneyCysteine proteinase SCTS

Cysteine protease inhibition (block active site, reduce protein breakdown); Modulation of immune cell function and antigen presentation; Reduction of extracellular matrix degradation