The antagonistic roles of PDGF and integrin αvβ3 in regulating ROS production at focal adhesions.

Reactive oxygen species (ROS) have been shown to play crucial roles in regulating various cellular functions, e.g. focal adhesion (FA) dynamics and cell migration upon growth factor stimulation.

FRET-based assays to monitor DNA binding and annealing by Rad52 recombination mediator protein.

During homologous recombination and homology-directed repair of broken chromosomes, proteins that mediate and oppose recombination form dynamic complexes on damaged DNA. Quantitative analysis of these nucleoprotein assemblies requires a robust signal, which reports on the association of a recombination mediator with its substrate and on the state of substrate DNA within the complex. Eukaryotic Rad52 protein mediates recombination, repair, and restart of collapsed replication forks by facilitating replacement of ssDNA binding protein replication protein A (RPA) with Rad51 recombinase and by mediating annealing of two complementary DNA strands protected by RPA.

Human Rad52 binds and wraps single-stranded DNA and mediates annealing via two hRad52-ssDNA complexes.

Rad52 promotes the annealing of complementary strands of DNA bound by replication protein A (RPA) during discrete repair pathways. Here, we used a fluorescence resonance energy transfer (FRET) between two fluorescent dyes incorporated into DNA substrates to probe the mechanism by which human Rad52 (hRad52) interacts with and mediates annealing of ssDNA-hRPA complexes. Human Rad52 bound ssDNA or ssDNA-hRPA complex in two, concentration-dependent modes.

Human Rad52-mediated homology search and annealing occurs by continuous interactions between overlapping nucleoprotein complexes.

The Rad52 protein has critical functions in distinct pathways of the homology-directed DNA repair, one of which is to promote the annealing of complementary strands of DNA. Both yeast and human Rad52 proteins organize into ring-shaped oligomers with the predominant form being a heptamer. Despite the wealth of information obtained in previous investigations, how Rad52 mediates homology search and annealing remains unclear.