mArSTED · Stepping into the light: exploring mono-ADP-ribosylation through super resolution STED microscopy

ADP-ribosylation (ADPr) is a key post-translational modification catalyzed by the ADP-ribosyltransferase (ART) superfamily, including poly-ADP-ribose polymerases (PARPs), which, despite their name, can transfer either a single (mono-ADPr) or multiple (poly-ADPr; PAR) units of ADP-ribose to their targets. This process occurs in response to various biological and pathological stimuli, regulating numerous cellular functions. For many years, research in the ADPr field focused primarily on poly-ADPr PARPs, often overlooking the physiological importance and therapeutic potential of mono-PARPs. Recently, the development of new reagents, including versatile antibodies to detect mono-ADPr, provided essential tools to finally explore this elusive modification. Emerging evidence, partly obtained by using these antibodies, suggests that mono-ADPr responses could be promising therapeutic targets for immune-related diseases, pushing mono-ADPr into the spotlight. However, this growing pharmaceutical interest contrasts with our limited understanding of the molecular mechanisms and biological functions of mono-ADPr and the catalyzing enzymes. In this MSCA project, I aim to shed light on the functions of the underexplored mono-ADP-ribosylation by pioneering the development of super-resolution microscopy methods to visualize mono-ADPr localization across different cellular structures. Through this cutting-edge approach, my research will provide unprecedented insights into the spatial dynamics of mono-ADPr, potentially uncovering novel aspects of its functional roles in cells and providing powerful new methods for the ADP-ribosylation field. Additionally, I will investigate the crosstalk between two PARPs that, according to preliminary data from the host lab, may collaboratively mediate ADPr at the nuclear pore complex, providing insights into the molecular mechanisms underlying the findings from our microscopy studies.