Replication stress response protein that accumulates at DNA damage sites and promotes replication fork progression and integrity (PubMed:27601467, PubMed:27723720, PubMed:27723717). Recruited to stalled replication forks via interaction with the RPA complex and directly stimulates ATR kinase activity independently of TOPBP1 (PubMed:27723720, PubMed:27723717). Probably only regulates a subset of ATR targets (PubMed:27723720, PubMed:27723717).
