proteasome core complex, beta-subunit complex

Definition

Target type: cellularcomponent

The proteasome core subcomplex that constitutes the two inner rings of the proteasome core complex. An example of this component is found in Mus musculus. [GOC:jl, GOC:mtg_sensu, GOC:rb, PMID:10854779]

The proteasome core complex, beta-subunit complex, is a crucial component of the ubiquitin-proteasome system (UPS), responsible for degrading misfolded, damaged, or regulatory proteins within eukaryotic cells. This complex, also known as the 20S proteasome, is a cylindrical structure composed of four stacked rings, each with seven subunits. The two outer rings are formed by seven alpha-subunits (α1-α7), while the two inner rings are formed by seven beta-subunits (β1-β7). These beta-subunits are responsible for the proteolytic activity of the complex.

Specifically, the beta-subunit complex contains three catalytically active subunits:

* **β1 (PSMB6):** This subunit has chymotrypsin-like activity, cleaving after hydrophobic residues.
* **β2 (PSMB7):** This subunit exhibits trypsin-like activity, cleaving after basic residues (lysine and arginine).
* **β5 (PSMB5):** This subunit possesses caspase-like activity, cleaving after acidic residues (glutamate and aspartate).

These active sites are located within the central chamber of the proteasome, where protein substrates are unfolded and degraded. The beta-subunit complex is highly regulated, with its activity controlled by a variety of factors, including the presence of ubiquitinated substrates, ATP, and specific inhibitors. It plays a vital role in maintaining cellular homeostasis, participating in various processes such as cell cycle control, immune response, and protein quality control. Damage or dysfunction of the proteasome core complex, particularly its beta-subunits, can lead to various diseases, including cancer, neurodegenerative disorders, and inflammatory conditions.'
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Proteins (11)

Compounds (59)