Poly(ADP-ribose): a signaling molecule in different paradigms of cell death.

Poly(ADP-ribosylation) results from the conversion of NAD(+) into ADP-ribose and the following addition of ADP-ribose units to form polymers, further bound to acceptor proteins; once post-translationally ADP-ribosylated, proteins could change their function in basic processes. Poly(ADP-ribosylation) is activated under critical situations represented by DNA damage and cellular stress, and modulated in different paradigms of cell death. The hallmarks of the main death processes, i.e. apoptosis, parthanatos, necroptosis and autophagy, will be described, focusing on the role of poly(ADP-ribose) as a signaling molecule.