Western blot analysis of 53BP1 phosphorylation in untreated (A,D), UV treated (B,E) and UV and lambda protein phosphatase (sc-200312A) treated (C,F) HeLa whole cell lysates. Antibodies tested include p-53BP1 (38.Ser 25): sc-135748 (A,B,C) and 53BP1 (H-300): sc-22760 (D,E,F).