Methods for Purification of Proteins Associated with Cellular Poly(ADP-Ribose) and PARP-Specific Poly(ADP-Ribose)

Poly(ADP-ribose) (pADPr) is a posttranslational modification that regulates protein function through two major mechanisms: covalent modification of acceptor proteins and noncovalent binding of proteins to pADPr. pADPr is synthesized by a family of enzymes called poly(ADP-ribose) polymerases (PARPs) that are themselves major targets of pADPr modification. Here, we outline two methods for the purification of pADPr-binding proteins via pADPr purification under native conditions: purification of cellular pADPr and pADPr covalently linked to specific PARPs. Together, these methods provide complementary approaches to the identification of noncovalent pADPr–protein interactions in the cell.