The discussion highlights the key differences between proteasomes and immunoproteasomes. A proteasome is an ATP-dependent, multi-subunit protease essential for intracellular protein degradation, functioning in healthy tissues and immune-privileged organs. It degrades protein substrates into peptide fragments, which are then presented on major histocompatibility complex (MHC) class I molecules. In contrast, an immunoproteasome is specifically expressed in response to cytokines like gamma interferon and tumor necrosis factor alpha, primarily in lymphoid organs. During immune responses, particularly antiviral and antibacterial, immunoproteasomes replace constitutive proteasomes, enhancing MHC class I restricted antigen presentation, which is crucial for effective immune responses.