Immunoproteasomes are commonly expressed in cells of the immune system, but they can also be induced in non-immune cells upon exposure to proinflammatory cytokines such as interferons (IFN) [100] or tumor necrosis factor (TNF) [101,102], environmental stress (e.g., heat shock [103]), aging [104] or neurodegenerative diseases [105,106]. The gene discussed is TNF; the disease is neurodegenerative disease.