| Structural highlights
Function
TOPB1_HUMAN Required for DNA replication. Plays a role in the rescue of stalled replication forks and checkpoint control. Binds double-stranded DNA breaks and nicks as well as single-stranded DNA. Recruits the SWI/SNF chromatin remodeling complex to E2F1-responsive promoters. Down-regulates E2F1 activity and inhibits E2F1-dependent apoptosis during G1/S transition and after DNA damage. Induces a large increase in the kinase activity of ATR.[1] [2] [3] [4] [5] [6]
Publication Abstract from PubMed
The checkpoint kinase ATR [ATM (ataxia-telangiectasia mutated) and rad3-related] is a master regulator of DNA damage response. Yet, how ATR activity is regulated remains to be investigated. We report here that histone demethylase PHF8 (plant homeodomain finger protein 8) plays a key role in ATR activation and replication stress response. Mechanistically, PHF8 interacts with and demethylates TOPBP1 (DNA topoisomerase 2-binding protein 1), an essential allosteric activator of ATR, under unperturbed conditions, but replication stress results in PHF8 phosphorylation and dissociation from TOPBP1. Consequently, hypomethylated TOPBP1 facilitates RAD9 (RADiation sensitive 9) binding and chromatin loading of the TOPBP1-RAD9 complex to fully activate ATR and thus safeguard the genome and protect cells against replication stress. Our study uncovers a demethylation and phosphorylation code that controls the assembly of TOPBP1-scaffolded protein complex, and provides molecular insight into non-histone methylation switch in ATR activation.
PHF8-promoted TOPBP1 demethylation drives ATR activation and preserves genome stability.,Ma S, Cao C, Che S, Wang Y, Su D, Liu S, Gong W, Liu L, Sun J, Zhao J, Wang Q, Song N, Ge T, Guo Q, Tian S, Chen CD, Zhang T, Wang J, Ding X, Yang F, Ying G, Yang J, Zhang K, Zhu Y, Yao Z, Yang N, Shi L Sci Adv. 2021 May 5;7(19):eabf7684. doi: 10.1126/sciadv.abf7684. Print 2021 May. PMID:33952527[7]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Yamane K, Tsuruo T. Conserved BRCT regions of TopBP1 and of the tumor suppressor BRCA1 bind strand breaks and termini of DNA. Oncogene. 1999 Sep 16;18(37):5194-203. PMID:10498869 doi:10.1038/sj.onc.1202922
- ↑ Makiniemi M, Hillukkala T, Tuusa J, Reini K, Vaara M, Huang D, Pospiech H, Majuri I, Westerling T, Makela TP, Syvaoja JE. BRCT domain-containing protein TopBP1 functions in DNA replication and damage response. J Biol Chem. 2001 Aug 10;276(32):30399-406. Epub 2001 Jun 6. PMID:11395493 doi:10.1074/jbc.M102245200
- ↑ Honda Y, Tojo M, Matsuzaki K, Anan T, Matsumoto M, Ando M, Saya H, Nakao M. Cooperation of HECT-domain ubiquitin ligase hHYD and DNA topoisomerase II-binding protein for DNA damage response. J Biol Chem. 2002 Feb 1;277(5):3599-605. Epub 2001 Nov 19. PMID:11714696 doi:10.1074/jbc.M104347200
- ↑ Liu K, Lin FT, Ruppert JM, Lin WC. Regulation of E2F1 by BRCT domain-containing protein TopBP1. Mol Cell Biol. 2003 May;23(9):3287-304. PMID:12697828
- ↑ Liu K, Luo Y, Lin FT, Lin WC. TopBP1 recruits Brg1/Brm to repress E2F1-induced apoptosis, a novel pRb-independent and E2F1-specific control for cell survival. Genes Dev. 2004 Mar 15;18(6):673-86. PMID:15075294 doi:10.1101/gad.1180204
- ↑ Kumagai A, Lee J, Yoo HY, Dunphy WG. TopBP1 activates the ATR-ATRIP complex. Cell. 2006 Mar 10;124(5):943-55. PMID:16530042 doi:10.1016/j.cell.2005.12.041
- ↑ Ma S, Cao C, Che S, Wang Y, Su D, Liu S, Gong W, Liu L, Sun J, Zhao J, Wang Q, Song N, Ge T, Guo Q, Tian S, Chen CD, Zhang T, Wang J, Ding X, Yang F, Ying G, Yang J, Zhang K, Zhu Y, Yao Z, Yang N, Shi L. PHF8-promoted TOPBP1 demethylation drives ATR activation and preserves genome stability. Sci Adv. 2021 May 5;7(19):eabf7684. PMID:33952527 doi:10.1126/sciadv.abf7684
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