A large protein complex that degrades proteins that have been tagged for elimination, particularly those tagged by ubiquitination.
Type of large protein complex in the cytosol that is responsible for degrading proteins that have been marked for destruction by ubiquitination or by some other means.
A joined group (or complex) of enzymes that destroy damaged or unwanted proteins and undamaged proteins that require degradation in the cell. This turnover or “recycling†of proteins is important to maintain balance within the cell and helps to regulate several functions including cell growth.
A multisubunit protein structure that is involved in the degradation of other proteins.
a proteasome is the evil twin of a chaperonin. Like a chaperonin, it is a longitudinally symmetrical series of 7-member rings (but four rings, not two) with a hole through the middle and an affinity for improperly-folded polypeptides. Unlike a chaperonin, a proteasome does not restore proteins to conformational health and send them on their way. Instead, the proteasome slashes the doomed polypeptide into little 7-13 amino acid oligopeptides so that they may be completely degraded by other proteases. Since its function is reclamation, not rehabilitation, a proteasome lacks any of the bells and whistles of a chaperonin and possesses a much narrower aperture. Thus, only proteins which are more or less completely unfolded can pass into the destructive core of the complex. The basic 20S proteasome is found in Actinobacteria and Archea. In eukaryotes, the 20S structure forms the core of a 26S proteasome. Image from the Max-Planck-Institut für Biochemie, Abteilung für Strukturforschung.
A large, multiprotein complex present in both the cytoplasm and the nucleus of eukaryotic cells that degrades cytosolic and nuclear proteins.
A large barrel-shaped multi-subunit complex, which harbours several protease activities. Substrates are threaded into the barrel, where they are degraded by the proteases.
A large, multisubunit, multicatalytic complex of proteins proposed to play a role in antigen processing.
Large multifunctional protease complex in the cytosol that degrades intracellular proteins marked for destruction by attachment of multiple ubiquitin molecules. ( Figure 3-18)
a large multiprotein complex found in all cells that functions in degradation of ubiquitylated proteins. (More? UNSW Cell Biology)
Complex of enzymes found within cells that play a key role in the regulation of cell function and growth. Proteasomes break down and clear out proteins after they've done their job and are no longer needed. Some cancer cells appear to be particularly dependent on proteasomes to grow and survive and undergo programmed cell death (apoptosis) if proteasome activity is blocked.
a large protein complex that helps destroy other cellular proteins when they are no longer needed
A specialized organelle within the cytoplasm of a cell that is responsible for degradation of cytoplasmically situated proteins. The proteasome plays a key role in normal protein turnover and in peptide presentation by MHC Class I antigen.
a structure in cells where damaged or unneeded proteins are broken down.
complex of proteases whose function is to fragment proteins into peptides.
(PRO-tee-uh-some) A cellular machine that digests proteins that have been tagged with ubiquitin for destruction.
Proteasomes are large protein complexes inside all eukaryotes and archaea, as well as some bacteria. In eukaryotes, they are located in the nucleus and the cytoplasm.Peters JM, Franke WW, Kleinschmidt JA. (1994) Distinct 19S and 20S subcomplexes of the 26S proteasome and their distribution in the nucleus and the cytoplasm. J Biol Chem, Mar 11;269(10):7709-18.