proteasome assembly

Definition

Target type: biologicalprocess

The aggregation, arrangement and bonding together of a mature, active proteasome complex. [GOC:go_curators, PMID:10872471]

The proteasome, a large, multi-subunit protein complex responsible for degrading misfolded and damaged proteins, undergoes a complex assembly process involving multiple steps and specialized chaperones. The process begins with the formation of the 20S core particle, the proteolytic chamber, which is assembled from two heptameric rings of alpha subunits and two heptameric rings of beta subunits. These rings stack together forming a barrel-like structure with a central cavity containing the active sites responsible for proteolysis. Prior to their incorporation into the 20S core particle, the beta subunits are synthesized as inactive precursors. They undergo a series of maturation steps, including activation of the active sites and removal of N-terminal propeptides. Chaperones play crucial roles throughout the assembly process. For instance, the chaperone PA28 facilitates the association of the alpha and beta rings, while PA700 assists in the formation of the regulatory particle (RP), the gatekeeper that controls entry of proteins into the proteasome. The RP consists of two 19S regulatory particles, each composed of a base subcomplex and a lid subcomplex. The base subcomplex interacts with the 20S core particle and is involved in substrate recognition and unfolding. The lid subcomplex functions in ATP-dependent unfolding and translocation of substrates into the 20S core particle. Once the RP assembles onto the 20S core particle, the final proteasome complex is formed, capable of recognizing, unfolding, and degrading proteins. The proteasome assembly process is tightly regulated, ensuring proper formation and function of this essential cellular machinery. Defects in proteasome assembly can lead to various diseases, highlighting its importance in maintaining cellular homeostasis.'
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Proteins (2)

Compounds (3)