title: Rad51 protein stimulates the branch migration activity of Rad54 protein.
abstract: The Rad51 and Rad54 proteins play important roles during homologous recombination in eukaryotes. Rad51 forms a nucleoprotein filament on single-stranded DNA and performs the initial steps of double strand break repair. Rad54 belongs to the Swi2/Snf2 family of ATP-dependent DNA translocases. We previously showed that Rad54 promotes branch migration of Holliday junctions. Here we find that human Rad51 (hRad51) significantly stimulates the branch migration activity of hRad54. The stimulation appears to be evolutionarily conserved, as yeast Rad51 also stimulates the branch migration activity of yeast Rad54. We further investigated the mechanism of this stimulation. Our results demonstrate that the stimulation of hRad54-promoted branch migration by hRad51 is driven by specific protein-protein interactions, and the active form of the hRad51 filament is more stimulatory than the inactive one. The current results support the hypothesis that the hRad51 conformation state has a strong effect on interaction with hRad54 and ultimately on the function of hRad54 in homologous recombination.
authors.affiliation: Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102-1192, USA.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Rossi
authors.forename: Alexander V
authors.initials: AV
authors.lastname: Mazin
mesh_terms: D004265:DNA Helicases; D045566:DNA, Cruciform / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D004277:DNA, Single-Stranded / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins; D019143:Evolution, Molecular; D006801:Humans; D009687:Nuclear Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D051135:Rad51 Recombinase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011995:Recombination, Genetic / Q000502:physiology; D012441:Saccharomyces cerevisiae / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
chemical_list: D045566:DNA, Cruciform; D004277:DNA, Single-Stranded; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D011994:Recombinant Proteins; D029701:Saccharomyces cerevisiae Proteins; C495151:RAD51 protein, S cerevisiae; C495153:RAD51 protein, human; D051135:Rad51 Recombinase; D004265:DNA Helicases; C103532:RAD54L protein, human