Proteasome

Definition

A proteasome is a large protein complex in cells responsible for degrading unwanted or damaged proteins by proteolysis, a chemical reaction that breaks peptide bonds. It plays a critical role in regulating various cellular processes by controlling the concentration of particular proteins and degrading misfolded proteins.

5 Must Know Facts For Your Next Test

1. Proteasomes recognize ubiquitin-tagged proteins for degradation.
2. The core particle of the proteasome has a barrel-like structure composed of four stacked rings.
3. ATP is required for the unfolding and translocation of substrates into the proteasome core.
4. Proteasome activity is crucial for cell cycle regulation, apoptosis, and DNA repair.
5. Inhibition of proteasomes can lead to the accumulation of defective proteins and has been explored as a therapeutic strategy in cancer treatment.

Review Questions

• What type of tag marks proteins for degradation by the proteasome?
• How many rings compose the core particle of the proteasome?
• Why is ATP necessary for proteasomal function?

Related terms

Ubiquitin: A small protein that tags other proteins for degradation by the proteasome.

Autophagy: A process that involves the degradation of cellular components through lysosomal machinery.

Chaperone Proteins: Proteins that assist in folding other proteins correctly and preventing misfolding or aggregation.