Adp-ribosylation

Definition

ADP-ribosylation is a post-translational modification process where an ADP-ribose molecule is transferred from NAD+ to a target protein, leading to changes in the protein's function, stability, or interactions. This modification can significantly impact cellular processes, including DNA repair and cell signaling, thereby influencing gene expression and epigenetic regulation.

5 Must Know Facts For Your Next Test

1. ADP-ribosylation can regulate various cellular functions by altering the activity of proteins involved in signaling pathways and DNA repair mechanisms.
2. It can be reversible, allowing cells to respond quickly to changes in their environment by removing or adding ADP-ribose groups.
3. Different enzymes can catalyze ADP-ribosylation, leading to diverse outcomes depending on the target protein and the context within the cell.
4. This modification plays an important role in epigenetic regulation by influencing the structure of chromatin and the accessibility of DNA for transcription.
5. ADP-ribosylation is implicated in various diseases, including cancer, where altered expression of ADP-ribosylating enzymes can affect tumor progression.

Review Questions

• How does adp-ribosylation affect protein function and what implications does this have for cellular processes?
  • ADP-ribosylation modifies proteins by adding ADP-ribose molecules, which can change their activity, stability, or interactions with other molecules. This alteration can significantly influence critical cellular processes like signaling pathways and DNA repair. As a result, these changes play a pivotal role in regulating gene expression and ultimately affect how cells respond to various stimuli.
• Discuss the role of poly(ADP-ribose) polymerase (PARP) in the context of adp-ribosylation and its implications for genomic stability.
  • Poly(ADP-ribose) polymerase (PARP) is essential for catalyzing the addition of ADP-ribose units to target proteins. It plays a crucial role in DNA repair mechanisms by facilitating the recruitment of repair proteins to sites of damage. This process helps maintain genomic stability; however, if PARP activity is dysregulated, it can lead to impaired DNA repair and contribute to the development of diseases such as cancer.
• Evaluate the significance of adp-ribosylation in epigenetic regulation and how it may influence disease outcomes.
  • ADP-ribosylation is significant in epigenetic regulation as it alters chromatin structure, thereby influencing DNA accessibility for transcription. This modification allows cells to dynamically regulate gene expression based on environmental changes. In disease contexts like cancer, abnormal patterns of adp-ribosylation can disrupt normal epigenetic control, leading to altered gene expression profiles that contribute to tumor progression and treatment resistance.

Related terms

NAD+: Nicotinamide adenine dinucleotide, a coenzyme involved in redox reactions and also serves as a substrate for ADP-ribosylation.

Poly(ADP-ribose) polymerase (PARP): An enzyme that catalyzes the addition of ADP-ribose units to proteins and plays a crucial role in DNA repair and maintaining genomic stability.

Histone Modifications: Chemical modifications on histone proteins that alter chromatin structure and influence gene expression; ADP-ribosylation can be one of these modifications.