protein K48-linked deubiquitination

Definition

Target type: biologicalprocess

A protein deubiquitination process in which a K48-linked ubiquitin chain, i.e. a polymer of ubiquitin formed by linkages between lysine residues at position 48 of the ubiquitin monomers, is removed from a protein. [GOC:mah]

K48-linked deubiquitination is a critical cellular process that involves the removal of ubiquitin chains linked via lysine 48 (K48) from target proteins. This process plays a central role in regulating diverse cellular functions, including protein degradation, signal transduction, and DNA repair.

Ubiquitination, the attachment of ubiquitin monomers to target proteins, is a highly dynamic and reversible process. Ubiquitin is a small, highly conserved protein that can be attached to target proteins as single units or as polyubiquitin chains. The specific type of ubiquitin linkage, determined by the lysine residue on ubiquitin involved in the chain formation, dictates the fate of the target protein.

K48-linked polyubiquitination is the most common signal for protein degradation via the proteasome. When a protein is tagged with a K48-linked polyubiquitin chain, it is recognized and degraded by the proteasome, a large protein complex responsible for the breakdown of misfolded or damaged proteins. This process is crucial for maintaining cellular homeostasis and preventing the accumulation of potentially harmful proteins.

K48-linked deubiquitination, conversely, removes K48-linked polyubiquitin chains from target proteins, preventing their degradation by the proteasome. This process is mediated by a family of enzymes known as deubiquitinases (DUBs). DUBs are highly specific for the type of ubiquitin linkage they cleave, and they can regulate the stability and activity of their target proteins.

Deubiquitination can have several biological consequences:

- **Regulation of protein degradation:** DUBs can prevent the degradation of proteins that are normally targeted for proteasomal degradation, thus extending their half-life and increasing their cellular activity.
- **Signal transduction:** Some DUBs are involved in regulating signal transduction pathways by removing ubiquitin chains from signaling proteins, thereby modulating their activity and downstream effects.
- **DNA repair:** DUBs play a role in DNA repair by removing ubiquitin chains from proteins involved in the DNA damage response, allowing these proteins to function properly and facilitate DNA repair.
- **Immune response:** Deubiquitination can regulate the activity of immune cells by modulating the expression of proteins involved in the immune response.

In summary, K48-linked deubiquitination is a crucial cellular process that removes K48-linked polyubiquitin chains from target proteins, thereby preventing their degradation and modulating their activity. DUBs play a critical role in this process, regulating a wide range of cellular functions and contributing to the maintenance of cellular homeostasis. The precise mechanisms and biological implications of deubiquitination are still under investigation, but this process is emerging as a key player in cellular regulation.'
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Proteins (3)

Compounds (7)