The quest to identify ADP-ribosylation readers: methodological advances

Interactions between ADP-ribose (ADPr) modifications and their readers play an essential role in various biological processes, and the toolbox for probing these interactions is expanding.Many methods for the discovery of ADPr readers rely on the activity of poly-ADPr (PAR) polymerase 1 (PARP1) to enzymatically synthesize PAR.Recent advances using (chemo)enzymatic methods include the incorporation of functional groups such as a photo-activatable azido group and/or the incorporation of a biotin-handle for affinity purifications.Chemically synthesized probes with a well-defined structure enable, for the first time, identification of mono-ADPr (MAR) and linear PAR-specific readers.An in-depth knowledge on ADPr modifications and their readers will aid in the discovery of novel therapeutic targets for multiple ADPr-associated pathologies. ADP-ribosylation regulates numerous fundamental cellular processes in health and disease. However, the limited availability of suitable tools and methods prevents the identification and characterization of certain components of the ADP-ribosylation signaling network and, consequently, efficient utilization of their biomedical potential. Identification of ADP-ribose (ADPr) readers has been particularly impeded by challenges associated with the development of ADPr-based enrichment probes. These difficulties were finally overcome in several recent studies describing various approaches to identifying ADPr readers in an unbiased, proteome-wide manner. In this review we discuss these different strategies and their limitations, benefits and drawbacks, and summarize how these technologies contribute to a dissection of ADP-ribosylation signaling networks. We also address unmet technological needs and future directions to investigate interactions with ADPr linkages. ADP-ribosylation regulates numerous fundamental cellular processes in health and disease. However, the limited availability of suitable tools and methods prevents the identification and characterization of certain components of the ADP-ribosylation signaling network and, consequently, efficient utilization of their biomedical potential. Identification of ADP-ribose (ADPr) readers has been particularly impeded by challenges associated with the development of ADPr-based enrichment probes. These difficulties were finally overcome in several recent studies describing various approaches to identifying ADPr readers in an unbiased, proteome-wide manner. In this review we discuss the