Prioritizing PARylation in DNA Damage and Repair
Measuring cellular poly ADP-ribosylation can unlock new anticancer strategies and approaches.
ADP-ribosylation, the attachment of ADP-ribose to proteins, is a common eukaryotic post-translational modification. It exists in two forms: mono ADP-ribosylation (MARylation), where individual units are attached to the protein in question, and poly ADP-ribosylation (PARylation), where proteins are bound to multi-ADP-ribose unit chains and branches. PARylation is integral to many key cellular functions, including signaling modulation and DNA repair.
Poly ADP-ribose polymerases (PARPs) mediate ADP ribosylation. Scientists have discovered seventeen PARP families in humans, but only members of the first five PARP families are capable of PARylation, with PARP1 being the most abundant.1 PARP1 is a prominent part of DNA repair pathways, detecting and binding to both single-stranded and double-stranded breaks. PARP1 then recruits repair proteins to the damage site by auto-PARylating itself.2 If DNA is excessively damaged beyond repair, apoptotic pathways shut down DNA repair mechanisms, characterized by PARP1 cleavage.3
PARylation is reversible and is undone by PAR erasers such as poly ADP-ribose glycohydrolase (PARG). This serves two main functions. First, it allows PARP proteins to maintain functionality by returning them to their inactive forms. PARG inhibition results in increases in sensitivity to DNA damage and disrupted DNA replication. Second, it prevents parthanatos, a caspase-independent cell death mechanism caused by cytoplasmic poly ADP-ribose accumulation.4
Given their roles in DNA replication and repair, it is unsurprising that scientists have targeted both PARP and PARG for anticancer efforts.2,4 Here, PARylation is an indicator of approach efficacy, and products such as the LysA™ Universal PARylation Assay Kit from BPS Biosciences gives scientists precise measurements in an easy-to-use package. Based on sandwich ELISA, this kit is capable of qualitative and quantitative measurements, includes controls and standards, does not detect MARylation, and is linear within the 100pM to 20nM PARylation range. Accurate PARylation measurements drive continued work on PARP- and PARG inhibitor-based therapeutic approaches, whether used alone or in combination with other strategies.
Learn more about measuring PARylation.
- Ummarino S, et al. Genes (Basel). 2021;12(3):446.
- Slade D. Genes Dev. 2020;34(5-6):360-94.
- Gobeil S, et al. Cell Death Differ. 2001;8:588-94.
- Harrision D, et al. Front Mol Biosci. 2020;7:191.