monoADPribosejä

MonoADP-ribose refers to a post-translational modification where a single adenosine diphosphate (ADP) ribose moiety is attached to a protein. This modification, known as mono(ADP-ribosyl)ation, is catalyzed by a family of enzymes called ADP-ribosyltransferases (ARTs). These enzymes transfer ADP-ribose from nicotinamide adenine dinucleotide (NAD+) to specific amino acid residues on target proteins, most commonly arginine, asparagine, glutamine, or cysteine.

The function of mono(ADP-ribosyl)ation is diverse and context-dependent. It plays crucial roles in various cellular processes including DNA repair, gene regulation, protein folding, and signal transduction pathways. The attachment of the bulky ADP-ribose group can alter the protein's structure, activity, localization, or its interactions with other molecules. For instance, mono(ADP-ribosyl)ation has been implicated in the response to DNA damage, where it can recruit repair proteins to damaged sites. It is also involved in modulating the activity of G proteins, which are key players in cellular signaling.

Unlike poly(ADP-ribosyl)ation, which involves the formation of long chains of ADP-ribose units, mono(ADP-ribosyl)ation involves the addition of only a single ADP-ribose unit. This distinction is important as the biochemical and biological consequences of these two modifications differ. The enzymes responsible for mono(ADP-ribosyl)ation, the ARTs, are a conserved family found across many species. The reversibility of mono(ADP-ribosyl)ation is mediated by ADP-ribose hydrolases, ensuring dynamic regulation of this modification.