Proteasome interaction with ubiquitinated substrates: from mechanisms to therapies
The 26S proteasome is responsible for regulated proteolysis in eukaryotic cells. Its substrates are diverse in structure, function, sequence length, and amino acid composition, and are targeted to the proteasome by post‐translational modification with ubiquitin. Ubiquitination occurs through a compl...
Gespeichert in:
Veröffentlicht in: | The FEBS journal 2021-09, Vol.288 (18), p.5231-5251 |
---|---|
Hauptverfasser: | , , , , |
Format: | Artikel |
Sprache: | eng |
Schlagworte: | |
Online-Zugang: | Volltext |
Tags: |
Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
|
Zusammenfassung: | The 26S proteasome is responsible for regulated proteolysis in eukaryotic cells. Its substrates are diverse in structure, function, sequence length, and amino acid composition, and are targeted to the proteasome by post‐translational modification with ubiquitin. Ubiquitination occurs through a complex enzymatic cascade and can also signal for other cellular events, unrelated to proteasome‐catalyzed degradation. Like other post‐translational protein modifications, ubiquitination is reversible, with ubiquitin chain hydrolysis catalyzed by the action of deubiquitinating enzymes (DUBs), ~ 90 of which exist in humans and allow for temporal events and dynamic ubiquitin‐chain remodeling. DUBs have been known for decades to be an integral part of the proteasome, as deubiquitination is coupled to substrate unfolding and translocation into the internal degradation chamber. Moreover, the proteasome also binds several ubiquitinating enzymes and shuttle factors that recruit ubiquitinated substrates. The role of this intricate machinery and how ubiquitinated substrates interact with proteasomes remains an area of active investigation. Here, we review what has been learned about the mechanisms used by the proteasome to bind ubiquitinated substrates, substrate shuttle factors, ubiquitination machinery, and DUBs. We also discuss many open questions that require further study or the development of innovative approaches to be answered. Finally, we address the promise of expanded therapeutic targeting that could benefit from such new discoveries.
The 26S proteasome is a sophisticated 2.5 MDa proteolytic biomachine that removes damaged or obsolete proteins from cells by digesting them into peptides. Proteasome substrates are so‐marked by post‐translational modification with ubiquitin, and consequently, recognition and removal of ubiquitin chains are vital to substrate processing. We describe mechanistic features of this process, highlighting the importance of conformational rearrangements and transient interactions in advancing ubiquitinated substrates from recognition to degradation. |
---|---|
ISSN: | 1742-464X 1742-4658 1742-4658 |
DOI: | 10.1111/febs.15638 |