GO:0072572 poly-ADP-D-ribose binding: Mechanism, Genes

Poly-ADP-D-ribose binding (GO:0072572) is a molecular function that enables proteins to recognize and interact with poly-ADP-D-ribose (pADPr), a post-translational modification polymer synthesized by PARP enzymes. This binding event is critical for the recruitment of DNA repair factors, chromatin remodelers, and signaling molecules to sites of cellular stress, thereby orchestrating the DNA damage response and other essential processes. Researchers study this function to understand how cells maintain genomic integrity and how its dysregulation contributes to diseases such as cancer and neurodegeneration. The specificity of pADPr binding is mediated by dedicated domains, including macrodomains, PAR-binding zinc fingers (PBZ), WWE domains, and BRCT repeats, which decode the pADPr signal. Given its central role in cellular stress responses, poly-ADP-D-ribose binding is a promising target for therapeutic development and a focus of intense biomedical research.

Poly-ADP-D-ribose binding is the molecular function of selectively and non-covalently interacting with polymeric ADP-D-ribose, a polymer composed of poly-ADP-D-ribose units linked through 1,2-glycosidic bonds at the ribose ring. This function is exhibited by proteins that contain specialized pADPr-binding domains and is essential for transmitting signals in processes such as DNA repair and cell death.

Poly-ADP-D-ribose binding is fundamental to the DNA damage response, as it recruits key repair proteins to sites of DNA breaks and regulates their activity. This function also influences chromatin remodeling, transcription, and cell death pathways, making it a central node in cellular stress signaling. Dysregulation of pADPr binding is linked to cancer, neurodegeneration, and inflammatory disorders, underscoring its clinical relevance. Understanding this function at the molecular level can guide the development of targeted therapies, such as PARP inhibitors, and inform CRISPR-based disease modeling.

The following genes encode proteins that bind poly-ADP-D-ribose or regulate its metabolism, and are commonly studied in the context of GO:0072572.

Poly-ADP-D-ribose binding is regulated at multiple levels. The synthesis of pADPr by PARP enzymes is tightly controlled by DNA damage signals and NAD+ availability. Conversely, catabolic enzymes such as PARG, ARH3, and TARG1 rapidly degrade pADPr to terminate signaling. Post-translational modifications of pADPr-binding proteins, including phosphorylation, can modulate their affinity for pADPr. Additionally, the expression levels of reader proteins are subject to transcriptional and post-transcriptional regulation, influencing the cellular response to stress.

Dysregulated poly-ADP-D-ribose binding is a hallmark of many cancers. Mutations in BRCA1 and other repair genes that rely on pADPr binding lead to homologous recombination deficiency, making tumors sensitive to PARP inhibitors. Overexpression of PARP1 and altered pADPr metabolism contribute to chemoresistance and tumor progression. Targeting pADPr-binding domains is a promising therapeutic strategy.

Defects in pADPr metabolism and binding are linked to neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS) and ataxia. Mutations in TARG1 cause a neurodegenerative syndrome characterized by pADPr accumulation and impaired DNA repair. Similarly, altered pADPr signaling contributes to neuronal death in Parkinson's and Alzheimer's diseases.

pADPr binding plays a role in inflammatory signaling. For example, TRPM2, a pADPr-binding ion channel, mediates calcium influx and cytokine release in immune cells. Dysregulation of this process is implicated in autoimmune and inflammatory diseases.

Recombinant pADPr-binding domains can be tested for binding to synthetic pADPr or PARylated proteins using pull-down assays, surface plasmon resonance (SPR), or isothermal titration calorimetry (ITC). These methods quantify affinity and specificity.

X-ray crystallography and cryo-electron microscopy (cryo-EM) reveal the atomic details of pADPr recognition by macrodomains, PBZ, WWE, and BRCT domains. These structures inform the design of inhibitors.

Fluorescently tagged pADPr-binding domains (e.g., AF1521 macrodomain) are used as probes to visualize pADPr accumulation at DNA damage sites in live cells. Co-localization with repair factors can be assessed by confocal microscopy.

Genome-wide CRISPR knockout screens identify genes required for pADPr-dependent processes, such as DNA repair. Mass spectrometry-based proteomics can identify pADPr-modified proteins and their interactors.

Researchers studying poly-ADP-D-ribose binding-related genes often need to determine whether a candidate gene is causally involved in DNA repair, stress signaling, or disease progression. EDITGENE provides a comprehensive suite of CRISPR services to generate precisely engineered cell models, enabling rigorous functional validation of pADPr-binding proteins and their domains.

Poly-ADP-D-ribose binding (GO:0072572) is a pivotal molecular function that orchestrates cellular responses to DNA damage and stress through the recruitment of specialized reader proteins. Its dysregulation is implicated in cancer, neurodegeneration, and inflammation, making it a prime target for therapeutic intervention. Advances in CRISPR-based models and screening technologies are accelerating the discovery of new pADPr-binding proteins and their roles in disease. EDITGENE's comprehensive services empower researchers to dissect this function with precision and speed.