hXRCC2 enhances ADP/ATP processing and strand exchange by hRAD51.
The assembly of bacterial RecA, and its human homolog hRAD51, into an operational ADP/ATP-regulated DNA-protein (nucleoprotein) filament is essential for homologous recombination repair (HRR). Yet hRAD51 lacks the coordinated ADP/ATP processing exhibited by RecA and is less efficient in HRR reactions in vitro. In this study, we demonstrate that hXRCC2, one of five other poorly understood non-redundant human mitotic RecA homologs (hRAD51B, hRAD51C, hRAD51D, hXRCC2, and hXRCC3), stimulates hRAD51 ATP processing. hXRCC2 also increases hRAD51-mediated DNA unwinding and strand exchange activities that are integral for HRR. Although there does not seem to be a long-lived interaction between hXRCC2 and hRAD51, we detail a strong adenosine nucleotide-regulated interaction between the hXRCC2-hRAD51D heterodimer and hRAD51. These observations begin to elucidate the separate and specialized functions of the human mitotic RecA homologs that enable an efficient nucleoprotein filament required for HRR.
Shim
Kang Sup
KS
Genetics and Molecular Biology Program, Department of Microbiology and Immunology, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA.
Schmutte
Christoph
C
Tombline
Gregory
G
Heinen
Christopher D
CD
Fishel
Richard
R
D000244:Adenosine Diphosphate / Q000737:chemistry / Q000378:metabolism*; D000251:Adenosine Triphosphatases / Q000737:chemistry; D000255:Adenosine Triphosphate / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism*; D000911:Antibodies, Monoclonal / Q000737:chemistry; D001665:Binding Sites; D015374:Biosensing Techniques; D002467:Cell Nucleus / Q000378:metabolism; D004247:DNA / Q000737:chemistry / Q000378:metabolism; D004260:DNA Repair; D004268:DNA-Binding Proteins / Q000378:metabolism* / Q000502:physiology*; D019281:Dimerization; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D005982:Glutathione Transferase / Q000378:metabolism; D006801:Humans; D006868:Hydrolysis; D007700:Kinetics; D008938:Mitosis; D011233:Precipitin Tests; D011485:Protein Binding; D051135:Rad51 Recombinase; D011995:Recombination, Genetic; D013997:Time Factors; D014466:Ultraviolet Rays
D000911:Antibodies, Monoclonal; D004268:DNA-Binding Proteins; C113187:XRCC2 protein, human; C022571:adenosine 5'-O-(3-thiotriphosphate); D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D004247:DNA; D005982:Glutathione Transferase; C495153:RAD51 protein, human; D051135:Rad51 Recombinase; D000251:Adenosine Triphosphatases