2lvm
From Proteopedia
Solution structure of human 53BP1 tandem Tudor domains in complex with a histone H4K20me2 peptide
Structural highlights
DiseaseTP53B_HUMAN Note=A chromosomal aberration involving TP53BP1 is found in a form of myeloproliferative disorder chronic with eosinophilia. Translocation t(5;15)(q33;q22) with PDGFRB creating a TP53BP1-PDGFRB fusion protein. FunctionTP53B_HUMAN Plays a key role in the response to DNA damage. May have a role in checkpoint signaling during mitosis. Enhances TP53-mediated transcriptional activation.[1] [2] Publication Abstract from PubMedThe pathogenic sequelae of BRCA1 mutation in human and mouse cells are mitigated by concomitant deletion of 53BP1, which binds histone H4 dimethylated at Lys20 (H4K20me2) to promote nonhomologous end joining, suggesting that a balance between BRCA1 and 53BP1 regulates DNA double strand-break (DSB) repair mechanism choice. Here we document that acetylation is a key determinant of this balance. TIP60 acetyltransferase deficiency reduced BRCA1 at DSB chromatin with commensurate increases in 53BP1, whereas HDAC inhibition yielded the opposite effect. TIP60-dependent H4 acetylation diminished 53BP1 binding to H4K20me2 in part through disruption of a salt bridge between H4K16 and Glu1551 in the 53BP1 Tudor domain. Moreover, TIP60 deficiency impaired homologous recombination and conferred sensitivity to PARP inhibition in a 53BP1-dependent manner. These findings demonstrate that acetylation in cis to H4K20me2 regulates relative BRCA1 and 53BP1 DSB chromatin occupancy to direct DNA repair mechanism. Acetylation limits 53BP1 association with damaged chromatin to promote homologous recombination.,Tang J, Cho NW, Cui G, Manion EM, Shanbhag NM, Botuyan MV, Mer G, Greenberg RA Nat Struct Mol Biol. 2013 Feb 3. doi: 10.1038/nsmb.2499. PMID:23377543[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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