The ADP-Ribosyl-Transferases Diphtheria Toxin-Like (ARTDs) Family: An Overview

Poly-ADP-ribosylation is a post-translational modification that occurs in multicellular organisms, including plants and some lower unicellular eukaryotes. The founding member of the PARP family is PARP1. To date, 17 members of the PARP family have been identified, which differ from each other in terms of domain organization, transmodification targets, cellular localization, and biological functions. In recent years, considering structural and biochemical features of the different members of the PARP family, a new classification has been proposed. Thus, enzymes firstly classified as PARP are now named diphtheria-toxin-like ARTs, abbreviated to ARTDs, in accordance with the prototype bacterial toxin that their structural aspects resemble, with numbers indicating the different proteins of the family. The 17 human ARTD enzymes can be divided on the basis of their catalytic activity into polymerases (ARTD1–6), mono-ADP-ribosyl-transferases (ARTD7–17), and the inactive ARTD13. In recent years, ADP-ribosylation was intensively studied, and research was dominated by studies focusing on the role of this modification and its implication on various cellular processes. The aim of this review is to provide a general overview of the ARTD enzymes, with a special focus on mono-ARTDs.