Tumor suppressor p53-binding protein 1 also known as p53-binding protein 1 or 53BP1 is a protein that in humans is encoded by the TP53BP1gene.[5][6][7]
DNA double-strand breaks (DSBs) are cytotoxic damages that can be repaired either by the homologous recombinational repair (HR) pathway or by the non-homologous end-joining (NHEJ) pathway. NHEJ, although faster than HR, is less accurate. The early divergent step between the two pathways is end resection, and this step is regulated by numerous factors. In particular, BRCA1 and 53BP1 play a role in determining the balance between the two pathways.[9][10] 53BP1 restricts resection and promotes NHEJ.
Age-associated deficient repair
Ordinarily during the G1 phase of the cell cycle, when a sister chromatid is unavailable for HR, NHEJ is the predominant pathway for repairing DNA double-strand breaks (DSBs). However, as individuals age, recruitment of 53BP1 to DSBs during G1 becomes deficient.[11] The absence of 53BP1 at such DSBs appears to promote the alternative error-prone repair process Alt-EJ.[11] This repair process, also referred to as microhomology-mediated end joining, is highly inaccurate and likely contributes to the aging process.
^Derbyshire DJ, Basu BP, Date T, Iwabuchi K, Doherty AJ (Oct 2002). "Purification, crystallization and preliminary X-ray analysis of the BRCT domains of human 53BP1 bound to the p53 tumour suppressor". Acta Crystallographica Section D. 58 (Pt 10 Pt 2): 1826–9. Bibcode:2002AcCrD..58.1826D. doi:10.1107/S0907444902010910. PMID12351827.
Wen Y, Yan DH, Spohn B, Deng J, Lin SY, Hung MC (Jan 2000). "Tumor suppression and sensitization to tumor necrosis factor alpha-induced apoptosis by an interferon-inducible protein, p202, in breast cancer cells". Cancer Research. 60 (1): 42–6. PMID10646849.
Derbyshire DJ, Basu BP, Date T, Iwabuchi K, Doherty AJ (Oct 2002). "Purification, crystallization and preliminary X-ray analysis of the BRCT domains of human 53BP1 bound to the p53 tumour suppressor". Acta Crystallographica Section D. 58 (Pt 10 Pt 2): 1826–9. Bibcode:2002AcCrD..58.1826D. doi:10.1107/S0907444902010910. PMID12351827.
DiTullio RA, Mochan TA, Venere M, Bartkova J, Sehested M, Bartek J, Halazonetis TD (Dec 2002). "53BP1 functions in an ATM-dependent checkpoint pathway that is constitutively activated in human cancer". Nature Cell Biology. 4 (12): 998–1002. doi:10.1038/ncb892. PMID12447382. S2CID7430614.
Fernandez-Capetillo O, Chen HT, Celeste A, Ward I, Romanienko PJ, Morales JC, Naka K, Xia Z, Camerini-Otero RD, Motoyama N, Carpenter PB, Bonner WM, Chen J, Nussenzweig A (Dec 2002). "DNA damage-induced G2-M checkpoint activation by histone H2AX and 53BP1". Nature Cell Biology. 4 (12): 993–7. doi:10.1038/ncb884. PMID12447390. S2CID12380387.
Yan DH, Abramian A, Li Z, Ding Y, Wen Y, Liu TJ, Hunt K (Mar 2003). "P202, an interferon-inducible protein, inhibits E2F1-mediated apoptosis in prostate cancer cells". Biochemical and Biophysical Research Communications. 303 (1): 219–22. doi:10.1016/S0006-291X(03)00320-6. PMID12646190.