INHIBITION OF DNA-BINDING BY THE PHOSPHORYLATION OF POLY ADP-RIBOSE POLYMERASE PROTEIN CATALYZED BY PROTEIN-KINASE-C

Purified type II (β) and type III (α) protein kinase C phosphorylates highly purified polyADP-ribose polymerase in vitro whereby 2 mols of phosphate are transferred from ATP to serine and threonine residues present in the 36 and 56 kDa polypeptide domains of the polymerase protein. Calf thymus DNA was a non-competitive inhibitor of the protein kinase C catalyzed phosphorylation of polyADP-ribose polymerase. Coincidental with the phosphorylation of the protein the polymerase activity and DNA binding capacity of polyADP-ribose polymerase were inhibited. These in vitro findings may have possible cell biological significance in cellular signal transduction. © 1992.