5' to 3' DNA replicative helicase recruited to paused replisomes to promote fork progression throughout nonhistone protein-DNA complexes, naturally occurring impediments that are encountered in each S phase where replication forks pauses. Needed for normal fork progression through over 1000 discrete sites scattered throughout the genome, like rDNA, tRNA genes, centromeres, active replication origins, or transcriptional silencers. Required for timely replication of the telomere and subtelomeric DNA and for wild-type levels of telomeric silencing. Involved in regulation of Ty1 transposition and protects the genome from instability at nascent sites of retrotransposition. Involved in DNA repair during stalled replication fork, regulation of fragile sites expression and essential for genome stability. Also plays a role in mtDNA replication. Has G-quadruplex (G4) unwinding activity and can suppress G4-induced genome instability when PIF1 levels are low. ATP + H2O = ADP + H(+) + phosphate Interacts with DEF1 and POL30. The N-terminal part (residues 1 to 249) is essential for function and confers locus specificity. Present with 656 molecules/cell in log phase SD medium. Belongs to the helicase family.