DNA damage-induced CHK1 autophosphorylation at Ser296 is regulated by an intramolecular mechanism

CHK1 regulates the DNA damage-induced checkpoint involving an ATR- or ATM- dependent pathway. In this paper, we focused on the autophosphorylation of Ser296, one of the DNA damage-induced phosphorylation sites. First, we demonstrated that the Ser296 autophosphorylation of CHK1 is mainly regulated by an intramolecular mechanism in response to DNA damage. In examining the relationship between Ser296 and Ser317/Ser345, the other ATR dependent phosphorylation sites, we found that the Ser296 cis-autophosphorylation was dependent on both Ser317 and Ser345 phosphorylation. Our findings suggest that CHK1 mediates cell cycle checkpoint signals by both cis-autophosphorylation and trans-phosphorylation of downstream factors.Structured summary of protein interactionsCHK1phosphorylatesCHK1 by protein kinase assay (View Interaction: 1, 2, 3)

► Ser296 phosphorylation of CHK1 is regulated by an ATR-dependent pathway.
► CHK1 autophosphorylates at Ser296 via an intramolecular mechanism.
► Ser296 cis-autophosphorylation is dependent on Ser317 and Ser345 phosphorylation.