Poly ADP ribose (PAR) is a complex molecule made up of repeating units of adenosine diphosphate (ADP) ribose, which are linked together by glycosidic bonds. It is synthesized by the enzyme poly ADP ribose polymerase (PARP) as a response to DNA damage and plays a crucial role in DNA repair mechanisms and maintenance of genomic stability.
PAR is a versatile molecule that acts as a signaling molecule and a key mediator of various cellular processes. It is involved in the regulation of DNA repair pathways, chromatin structure, transcriptional regulation, and cell death pathways. PAR also serves as a docking site for multiple proteins involved in DNA damage repair, DNA replication, and chromatin remodeling, which enables their recruitment and coordinated action at the site of DNA damage.
PARylation, the addition of PAR to target proteins, occurs through the transfer of ADP-ribose units from NAD+ molecules. This post-translational modification modulates protein function, protein-protein interactions, and subcellular localization, thereby influencing various cellular processes and signaling pathways.
The dynamic and precise regulation of PARylation is essential for maintaining genomic integrity and cellular homeostasis. Dysregulation of PARylation has been implicated in various diseases, including cancer, neurodegenerative disorders, cardiovascular diseases, and autoimmune disorders.
In conclusion, poly ADP ribose (PAR) is a complex molecule synthesized in response to DNA damage that plays a pivotal role in DNA repair, cellular signaling, and maintenance of genomic stability. Its modification of various proteins through the process of PARylation contributes to the regulation of various cellular processes and is essential for overall cellular homeostasis.
