PARP-3 is a mono-ADP-ribosylase that activates PARP-1 in the absence of DNA.
The PARP-3 protein is closely related to the PARP-1 and PARP-2 proteins, which are involved in DNA repair and genome maintenance. Here, we characterized the biochemical properties of human PARP-3. PARP-3 is able to ADP-ribosylate itself as well as histone H1, a previously unknown substrate for PARP-3. PARP-3 is not ... activated upon binding to DNA and is a mono-ADP-ribosylase, in contrast to PARP-1 and PARP-2. PARP-3 interacts with PARP-1 and activates PARP-1 in the absence of DNA, resulting in synthesis of polymers of ADP-ribose. The N-terminal WGR domain of PARP-3 is involved in this activation. The functional interaction between PARP-3 and PARP-1 suggests that it may have a role in DNA repair. However, here we report that PARP-3 small interfering RNA-depleted cells are not sensitive to the topoisomerase I poison camptothecin, inducing DNA single-strand breaks, and repair these lesions as efficiently as wild-type cells. Altogether, these results suggest that the interaction between PARP-1 and PARP-3 is unrelated to DNA single-strand break repair.
Mesh Terms:
3-Iodobenzylguanidine, Adenosine Diphosphate Ribose, Camptothecin, Cell Cycle Proteins, DNA, DNA Breaks, Single-Stranded, DNA Repair, DNA Topoisomerases, Type I, Enzyme Inhibitors, Histones, Humans, Hydrolysis, Hydroxylamine, Mercuric Chloride, Poly(ADP-ribose) Polymerases, Protein Structure, Tertiary, RNA, Small Interfering, Topoisomerase I Inhibitors
3-Iodobenzylguanidine, Adenosine Diphosphate Ribose, Camptothecin, Cell Cycle Proteins, DNA, DNA Breaks, Single-Stranded, DNA Repair, DNA Topoisomerases, Type I, Enzyme Inhibitors, Histones, Humans, Hydrolysis, Hydroxylamine, Mercuric Chloride, Poly(ADP-ribose) Polymerases, Protein Structure, Tertiary, RNA, Small Interfering, Topoisomerase I Inhibitors
J. Biol. Chem.
Date: Mar. 12, 2010
PubMed ID: 20064938
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