Poly(ADP-ribose) binds to specific domains in DNA damage checkpoint proteins.
Poly(ADP-ribose) is formed in possibly all multicellular organisms by a familiy of poly(ADP-ribose) polymerases (PARPs). PARP-1, the best understood and until recently the only known member of this family, is a DNA damage signal protein catalyzing its automodification with multiple, variably sized ADP-ribose polymers that may contain up to 200 residues and several branching points. Through these polymers, PARP-1 can interact noncovalently with other proteins and alter their functions. Here we report the discovery of a poly(ADP-ribose)-binding sequence motif in several important DNA damage checkpoint proteins. The 20-amino acid motif contains two conserved regions: (i) a cluster rich in basic amino acids and (ii) a pattern of hydrophobic amino acids interspersed with basic residues. Using a combination of alanine scanning, polymer blot analysis, and photoaffinity labeling, we have identified poly(ADP-ribose)-binding sites in the following proteins: p53, p21(CIP1/WAF1), xeroderma pigmentosum group A complementing protein, MSH6, DNA ligase III, XRCC1, DNA polymerase epsilon, DNA-PK(CS), Ku70, NF-kappaB, inducible nitric-oxide synthase, caspase-activated DNase, and telomerase. The poly(ADP-ribose)-binding motif was found to overlap with five important functional domains responsible for (i) protein-protein interactions, (ii) DNA binding, (iii) nuclear localization, (iv) nuclear export, and (v) protein degradation. Thus, PARPs may target specific signal network proteins via poly(ADP-ribose) and regulate their domain functions.
Pleschke
J M
JM
Institute of Pharmacology and Toxicology, University of Zurich, Tierspital, Winterthurerstrasse 260, CH-8057 Zurich, Switzerland.
Kleczkowska
H E
HE
Strohm
M
M
Althaus
F R
FR
D000409:Alanine; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001665:Binding Sites; D002352:Carrier Proteins / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D004249:DNA Damage; D004260:DNA Repair; D051747:DNA-Activated Protein Kinase; D004268:DNA-Binding Proteins; D008969:Molecular Sequence Data; D011064:Poly Adenosine Diphosphate Ribose / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000502:physiology
D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D011064:Poly Adenosine Diphosphate Ribose; D051747:DNA-Activated Protein Kinase; D017346:Protein Serine-Threonine Kinases; D000409:Alanine