Studying catabolism of protein ADP-ribosylation

Protein ADP-ribosylation is a conserved post-translational modification that regulates many major cellular functions, such as DNA repair, transcription, translation, signal transduction, stress response, cell division, aging and cell death. Protein ADP-Ribosyl Transferases (ARTs) catalyse the transfer of an ADP-ribose (ADPr) group from -Nicotinamide Adenine Dinucleotide (-NAD+) cofactor onto a specific target protein with release of nicotinamide. ADP-ribosylation leads to changes in protein structure, function, stability and localisation thus defining the appropriate cellular response. The signalling by modifications needs to be finely tuned and eventually silenced and one of the ways to achieve this is through the action of enzymes that remove (reverse) protein ADP-ribosylation in a timely fashion such as PARG, TARG1 and MACROD1. Here, we describe several basic methods used to study the enzymatic activity of de-ADP-ribosylating enzymes.