A proteasome is a complex protein structure found in cells that plays a crucial role in degrading and recycling proteins. It helps maintain cellular health by breaking down damaged or unneeded proteins into smaller peptides, which can then be reused or eliminated. This process is essential for regulating various cellular functions, including the cell cycle and responses to stress. Proteasomes are part of the ubiquitin-proteasome system, where proteins marked with a small protein called ubiquitin are targeted for degradation. This system ensures that proteins are properly managed, preventing the accumulation of potentially harmful proteins and contributing to overall cellular homeostasis.