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Cytoplasmic organelle, composed of a cylindric core particle bound by two regulatory particles at each end, responsible for degrading endogenous proteins. Proteins to be destroyed are recognized by proteasomes because of the presence of ubiquitin conjugated to the targeted protein's lysine residue.
See also: ubiquitin-protease pathway.
[protease + -some ]


A cellular protein complex consisting of proteolytic enzymes that degrade endogenous proteins, especially those that are damaged, pathogenic, or no longer of use.


, proteosome (prō′tē-ă-sōm″)
An enzymatic (protease) cell organelle that degrades misfolded or damaged proteins and modulates the quantity of regulatory proteins in the cell. The breakdown of proteins by proteasomes (proteolysis) is triggered when damaged proteins are tagged by ubiquitin.


A large, cylindrical protein complex of several sub-units, present in the cytoplasm and nucleus of all cells and an essential component in cell metabolism. The function of the proteasome is to act as a kind of shredder, degrading unwanted proteins that have been tagged for destruction with UBIQUITIN chains. It strips proteins of their ubiquitin, unfolds them and catalyzed them to peptides. Proteasomes have aroused much interest as therapeutic trargets in cancer. The proteasome 26S is involved both in the induction and repression of APOPTOSIS. See also POLYUBIQUITINATION.
References in periodicals archive ?
B signaling pathway and proteasome activity in HDFs, which suggested an anti-inflammatory effect of shikonin.
A decrease in proteasome activity weakens the homeostatic cellular capacity to remove proteins that are either misfolded or need to be replenished, favoring the development of neurodegenerative diseases (Wang and Saunders, 2014).
Antiviral activity of proteasome inhibitors in herpes simplex virus-1 infection: role of nuclear factor-kappaB.
Intriguingly, recent studies proposed the impairment of proteasome activates autophagy, which might be a compensatory mechanism allowing eliminating ubiquitin-proteasome system (UPS) substrates [8, 9].
The role of ubiquitin proteasome system (UPS) in heart failure has been studied extensively in recent years.
As you age, the function of the proteasome declines, and the removal of damaged proteins slows.
MLN9708 is an investigational oral proteasome inhibitor that is being studied in multiple myeloma, various other hematologic malignancies and solid tumors.
In addition, we have previously reported that proteasome activity is decreased in the stenotic kidney of rats with angiotensin II-dependent renal hypertension [29, 30].
Researchers in the University of Leicester's Department of Biology discovered that chloroplasts are affected by the ubiquitin proteasome system (UPS) -- a process which causes the breakdown of unwanted proteins in cells, previously thought to only act on central parts of the cell.
Phase 1 trial of the proteasome inhibitor PS-341 in patients with refractory hematologic malignancies.

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