What is the function of the proteasome in protein quality control?

The proteasome plays a crucial role in maintaining protein quality control within the cell by degrading misfolded or damaged proteins. This process is essential for cellular health, as improperly folded proteins can lead to dysfunction and disease. The proteasome achieves this by recognizing and binding to proteins tagged for degradation, typically through a signal known as ubiquitination. Once the misfolded protein is identified, the proteasome unfolds it and translocates it into its catalytic core, where the protein is broken down into smaller peptides. This mechanism ensures that only properly folded and functional proteins remain available for the cell's various physiological processes. The ability of the proteasome to remove defective proteins is vital for preventing the accumulation of potentially toxic protein aggregates that can negatively impact cellular function.