**1. Introduction**

Repair of radiation-induced DNA damage requires a complex series of protein interactions. Single-stranded DNA (ssDNA) binding proteins (RPA/SSB) have long been known to play a passive, protective role in DNA replication and repair, by coating ssDNA. Recent evidence, however, suggests a much more active function for these ubiquitous proteins. In this review, we provide a summary of the background of ssDNA binding proteins, and incorporate recent experimental observations into current models of dynamic interactions between these proteins and cellular DNA repair enzymes. These results point to a highly choreographed, interactive mechanism, with RPA/SSB at the center of the coordination.
