Phosphorylation of Cdc25A at Ser-123 in response to DNA damage Authored: O'Connell, M, Walworth, N, 2003-06-05 08:03:09 Chk1 directly phosphorylates Cdc25A at Ser-123. Chk1 phosphorylation is required for cells to delay cell cycle progression in response to double-strand DNA breaks (Zhao et al., 2002). Edited: Matthews, L, 2003-09-10 06:00:00 Pubmed12399544 Reactome Database ID Release 4369591 Reactome, http://www.reactome.org ReactomeREACT_1680 Reviewed: Manfredi, J, 0000-00-00 00:00:00