Role of the mono(ADP)ribosylation of proteins in cellular regulation

In addition to its well established role as a cofactor in redox reactions, NAD+ serves also as a substrate for a ubiquitous group of enzymes called ADP-ribosyltransferases. These enzymes are found in the cytosol and in the nucleus of eukaryotic cells, they are involved as components of pathogenic bacterial toxins, and as part of a mechanism for inactivating host cell protein biosynthetic machinery in bacteriophage-infected cells. An overview of mono(ADP)ribosylation reactions is provided.