HEK 293, HCT116 and ATRflox cells were grown in DMEM supplemented with 10 percent foetal bovine serum. 53BP1 null mice are viable but are very tumor prone, (-)-MK 801 have problems in V J recombination and IgG course switching and are greatly hyersenstive to IR probably as a result of problem in nonhomologous end joining. Recent data suggest that 53BP1 is downregulated throughout the transition of precancerous level to carcinomas, and also loss of an individual 53BP1 allele in mice causes genome instability and lymphoma. At the cellular level, 53BP1 mouse embryo fibroblasts are mildly vulnerable to IR and show moderate problems in the IR induced G2 checkpoint. Individual cells depleted of 53BP1 using siRNA duplexes show a partial deficiency in the intra S stage checkpoint and also show defects in IR induced G2/M checkpoint after minimal doses of radiation. CHK2 phosphorylation is delayed in 53BP1 deficient cells and there is amarked reduction in the cross reactivity of IR treated cells with an antibody that recognises phospho SQ/TQ motifs qualified by ATM/ATR. Despite these findings, the complete molecular characteristics of 53BP1 its biological roles that are mediated by Urogenital pelvic malignancy are not comprehended. It’s broadly speaking thought that regardless of the molecular part of 53BP1, it is unique to DSBs.. This is mainly based on the observation that while 53BP1 colocalises with ATM at DSBs, it doesn’t translocate to websites of UV induced DNA damage. Earlier in the day studies indicated that exposure of cells to IR caused ATM dependent phosphorylation of 53BP1, as judged by electrophoretic mobility shift. To date, the sole known in vivo 53BP1 phosphorylation site are Ser25 and probably Ser29. In the span of our studies, we noticed that a 53BP1 protein, in which Ser25 and Ser29 are mutated to alanine residues, is still hyperphosphorylated in reaction to DNA damage. Here we report phosphorylation of 53BP1 at many book residues, using mass spectrometry and phospho specific Bazedoxifene ic50 antibodies, and demonstrate that ionising radiation stimulated phosphorylation of those residues involves ATM. Even though it is considered to be unique for DSBs, 53BP1 was found to be effectively phosphorylated at several story sites in reaction to UV irradiation in an ATMindependent, ATR dependent manner. All cells were maintained at 37 C in a humidified atmosphere containing five minutes CO2. The ATM inhibitor KU55933, organized at a focus of 10mMinDMSO, was kindly provided by Dr. Graeme Smith. To cause DNA harm, exponentially growing cells were treated with KU59333 or with clear car for 1h prior to exposure of cells to the indicated doses of IR or to the indicated dose of UV C irradiation. Samples were taken immediately ahead of irradiation, and at different times after treatment.