Species: Homo sapiens (Human). Function: May have a role in immune function. Probably involved in the processing of antigenic peptides during MHC class II-mediated antigen presentation. May play a role in activation-induced lymphocyte depletion in the thymus, and in neuronal degeneration and glial cell activation in the brain. Subcellular Location: Endosome. Protein Families: Peptidase A1 family. Tissue Specificity: Expressed abundantly in the stomach, the Clara cells of the lung and activated B-lymphocytes, and at lower levels in lymph nodes, skin and spleen. Not expressed in resting B-lymphocytes. Tag Info: C-terminal 6xHis-tagged.