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. Author manuscript; available in PMC: 2017 Oct 19.
Published in final edited form as: Cell. 2009 Feb 6;136(3):508–520. doi: 10.1016/j.cell.2008.12.021

Figure 6. DNA-PKcs and PIDD Affect G2/M DNA Damage Checkpoint.

Figure 6

(A)DNA-PKcs contributes to a G2/M checkpoint. Immortalized wild-type and DNA-PKcs knockout MEF lines were irradiated with 4 Gy, cultured for 2 and 6 hrs, and mitotic percentages were analyzed.

(B) DNA-PKcs kinase inhibitor influences the caspase-2 G2/M checkpoint. Isogenic wild-type and caspase-2-deficient MEF lines were incubated with 10 μM DNA-PKcs inhibitor for 1 hr, irradiated with 4 Gy of IR, and mitotic percentages were analyzed at 2 and 6 hrs post IR.

(C) Endogenous PIDD contributes to a G2/M checkpoint. Isogenic wild-type and PIDD knockout MEF lines were treated and analyzed the same as in A.

(D)Endogenous PIDD is required for a full activation of nuclear caspase-2. Nuclear extracts from PIDD cell lines treated identically as in C were analyzed by IB.

(E) PIDD-overexpression induces a stronger activation of a G2/M checkpoint. HeLa cells stably expressing an empty vector or FLAG-tagged PIDD (PIDD-stable) were exposed to 4 Gy IR, cultured for 1 and 2 hrs, and analyzed for mitotic percentages.

(F) Requirement of caspase-2 for PIDD to activate a G2/M checkpoint. Caspase-2-deficient MEFs [C2 (−/−)] stably expressing an empty vector (Vector-stable) or FLAG-tagged PIDD (PIDD-stable) were exposed to 4 Gy IR, cultured for additional 2 or 6 hrs, and analyzed for mitotic percentages.