3'-5' DNA helicase and substrate-recognition component of the SCF(FBH1 E3 ubiquitin ligase complex that plays a key role in response to stalled/damaged replication forks. Involved in genome maintenance by acting as an anti-recombinogenic helicase and preventing extensive strand exchange during homologous recombination: promotes RAD51 filament dissolution from stalled forks, thereby inhibiting homologous recombination and preventing excessive recombination. Also promotes cell death and DNA double-strand breakage in response to replication stress: together with MUS81, promotes the endonucleolytic DNA cleavage following prolonged replication stress via its helicase activity, possibly to eliminate cells with excessive replication stress. Plays a major role in remodeling of stalled DNA forks by catalyzing fork regression, in which the fork reverses and the two nascent DNA strands anneal. In addition to the helicase activity, also acts as the substrate-recognition component of the SCF(FBH1 E3 ubiquitin ligase complex, a complex that mediates ubiquitination of RAD51, leading to regulate RAD51 subcellular location.