Cystatins in Immune System

Abstract


Lysosomal cysteine proteases, the cathepsins, classified as clan C1, 1 were long believed to be responsible for the terminal protein degradation in the lysosomes. This view has changed since they are involved in a number of important cellular processes, such as antigen presentation, 2 bone resorption, 3 apoptosis 4 and protein processing, 5 as well as several pathologies such as cancer progression, 6 inflammation 7 and neurodegeneration. 8 So far, cathepsin D, an aspartic protease, and cysteine