Synonyms: Background:5'-3' DNA helicase involved in DNA damage response by acting as an inhibitor of DNA end resection(PubMed:25617833, PubMed:26774285). Recruitment to single-stranded DNA(ssDNA) following DNA damage leads to inhibit the nucleases catalyzing resection, such as EXO1, BLM and DNA2, possibly via the 5'-3' ssDNA translocase activity of HELB(PubMed:26774285). As cells approach S phase, DNA end resection is promoted by the nuclear export of HELB following phosphorylation(PubMed:26774285). Acts independently of TP53BP1(PubMed:26774285). Unwinds duplex DNA with 5'-3' polarity. Has single-strand DNA-dependent ATPase and DNA helicase activities. Prefers ATP and dATP as substrates(PubMed:12181327). During S phase, may facilitate cellular recovery from replication stress(PubMed:22194613).