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. Author manuscript; available in PMC: 2011 Oct 8.
Published in final edited form as: Mol Cell. 2010 Oct 8;40(1):1–2. doi: 10.1016/j.molcel.2010.09.020

Figure 1. The roles of Chk1 and MK2 in DNA damage induced checkpoint arrest.

Figure 1

In response to DNA damage, ATR and ATM signal through the p38/MK2 stress kinase cascade leading to the rapid translocation of MK2 from the nucleus to the cytoplasm. MK2 then phosphorylates hnRNP A0 leading to stabilization of Gadd45α mRNA, at the same time preventing Gadd45α mRNA degradation by phosphorylating the ribonuclease PARN. Gadd45α protein can then participate in a positive feedback loop to p38/MK2 thereby preventing mitotic entry during DNA damage repair by retaining Cdc25B/C in the cytoplasm.