Proteasome

Definition

The proteasome is a large protein complex that breaks down unwanted, damaged, misfolded, or short-lived proteins inside cells. Many proteins are first tagged with ubiquitin, a small regulatory protein, which helps direct them to the proteasome for degradation and recycling. [1] [2] [3]

Why It Matters in Ageing Research

The proteasome matters because protein quality control is essential for proteostasis, the maintenance of a healthy and functional protein network. Ageing is associated with increasing burdens of damaged or misfolded proteins, and impaired protein degradation can contribute to cellular stress, inflammation, neurodegeneration, and loss of tissue function. The proteasome is therefore a central part of the machinery that helps cells limit proteotoxic damage over time. [4] [5] [6]

Common Confusion

• The proteasome is not the same as autophagy; both degrade cellular material, but they handle different kinds of cargo through different systems.
• Proteasome activity is not always simply “good” or “bad”; cells need balanced protein degradation and protein synthesis.
• The proteasome degrades many normal short-lived regulatory proteins, not only damaged proteins.

Related Reading

• Proteostasis
• Autophagy
• Hallmarks of Ageing

References

1. Ciechanover, A. (2005). Proteolysis: from the lysosome to ubiquitin and the proteasome. https://doi.org/10.1038/nrm1552
2. Hershko, A., & Ciechanover, A. (1998). The ubiquitin system. https://doi.org/10.1146/annurev.biochem.67.1.425
3. Finley, D. (2009). Recognition and processing of ubiquitin-protein conjugates by the proteasome. https://doi.org/10.1146/annurev.biochem.78.081507.101607
4. Lopez-Otin, C., et al. (2013). The Hallmarks of Aging. https://doi.org/10.1016/j.cell.2013.05.039
5. Kaushik, S., & Cuervo, A. M. (2015). Proteostasis and aging. https://doi.org/10.1038/nm.4001
6. Vilchez, D., Saez, I., & Dillin, A. (2014). The role of protein clearance mechanisms in organismal ageing and age-related diseases. https://doi.org/10.1038/nrm3827