p-53BP1 Background Information 53BP1, also known as TP53BP1 (tumor protein p53 binding protein 1) or p202, is a 1,972 amino acid protein that is associated with kinetochores and contains two BRCT domains. Existing as multiple alternatively spliced isoforms, 53BP1 interacts with p53 and is thought to play a role in checkpoint signaling during mitosis, possibly enhancing p53-mediated transcriptional activation and influencing the cellular response to DNA damage. 53BP1 is subject to post-translational phosphorylation on specific amino acid residues, including Ser 1778, Ser 25 and Ser 29. The gene encoding 53BP1 maps to human chromosome 15, which houses over 700 genes and comprises nearly 3% of the human genome.
