| Structural highlights
Function
LCD1_YEAST Forms a complex with the serine/threonine kinase MEC1 which activates checkpoint signaling upon genotoxic stresses. The MEC1-LCD1 complex is recruited by the single-strand-binding protein complex RPA to DNA lesions in order to initiate the DNA repair by homologous recombination, after the MRX-complex and TEL1 are displaced. Required for the recruitment of MEC1 to DNA lesions, the activation of CHK1 and RAD53 kinases and phosphorylation of RAD9 in response to DNA damage. Required for cell growth and meiotic recombination.[1] [2] [3] [4] [5] [6] [7] [8] [9]
Publication Abstract from PubMed
In response to DNA damage or replication fork stalling, the basal activity of Mec1(ATR) is stimulated in a cell-cycle-dependent manner, leading to cell-cycle arrest and the promotion of DNA repair. Mec1(ATR) dysfunction leads to cell death in yeast and causes chromosome instability and embryonic lethality in mammals. Thus, ATR is a major target for cancer therapies in homologous recombination-deficient cancers. Here we identify a single mutation in Mec1, conserved in ATR, that results in constitutive activity. Using cryo-electron microscopy, we determine the structures of this constitutively active form (Mec1(F2244L)-Ddc2) at 2.8 A and the wild type at 3.8 A, both in complex with Mg(2+)-AMP-PNP. These structures yield a near-complete atomic model for Mec1-Ddc2 and uncover the molecular basis for low basal activity and the conformational changes required for activation. Combined with biochemical and genetic data, we discover key regulatory regions and propose a Mec1 activation mechanism.
Mechanism of auto-inhibition and activation of Mec1(ATR) checkpoint kinase.,Tannous EA, Yates LA, Zhang X, Burgers PM Nat Struct Mol Biol. 2021 Jan;28(1):50-61. doi: 10.1038/s41594-020-00522-0. Epub , 2020 Nov 9. PMID:33169019[10]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Paciotti V, Clerici M, Lucchini G, Longhese MP. The checkpoint protein Ddc2, functionally related to S. pombe Rad26, interacts with Mec1 and is regulated by Mec1-dependent phosphorylation in budding yeast. Genes Dev. 2000 Aug 15;14(16):2046-59. PMID:10950868
- ↑ Rouse J, Jackson SP. LCD1: an essential gene involved in checkpoint control and regulation of the MEC1 signalling pathway in Saccharomyces cerevisiae. EMBO J. 2000 Nov 1;19(21):5801-12. PMID:11060031 doi:http://dx.doi.org/10.1093/emboj/19.21.5801
- ↑ Wakayama T, Kondo T, Ando S, Matsumoto K, Sugimoto K. Pie1, a protein interacting with Mec1, controls cell growth and checkpoint responses in Saccharomyces cerevisiae. Mol Cell Biol. 2001 Feb;21(3):755-64. PMID:11154263 doi:http://dx.doi.org/10.1128/MCB.21.3.755-764.2001
- ↑ Clerici M, Paciotti V, Baldo V, Romano M, Lucchini G, Longhese MP. Hyperactivation of the yeast DNA damage checkpoint by TEL1 and DDC2 overexpression. EMBO J. 2001 Nov 15;20(22):6485-98. PMID:11707419 doi:http://dx.doi.org/10.1093/emboj/20.22.6485
- ↑ Rouse J, Jackson SP. Lcd1p recruits Mec1p to DNA lesions in vitro and in vivo. Mol Cell. 2002 Apr;9(4):857-69. PMID:11983176
- ↑ Enomoto S, Glowczewski L, Berman J. MEC3, MEC1, and DDC2 are essential components of a telomere checkpoint pathway required for cell cycle arrest during senescence in Saccharomyces cerevisiae. Mol Biol Cell. 2002 Aug;13(8):2626-38. PMID:12181334 doi:http://dx.doi.org/10.1091/mbc.02-02-0012
- ↑ Lisby M, Barlow JH, Burgess RC, Rothstein R. Choreography of the DNA damage response: spatiotemporal relationships among checkpoint and repair proteins. Cell. 2004 Sep 17;118(6):699-713. PMID:15369670 doi:http://dx.doi.org/10.1016/j.cell.2004.08.015
- ↑ Nakada D, Hirano Y, Tanaka Y, Sugimoto K. Role of the C terminus of Mec1 checkpoint kinase in its localization to sites of DNA damage. Mol Biol Cell. 2005 Nov;16(11):5227-35. Epub 2005 Sep 7. PMID:16148046 doi:http://dx.doi.org/E05-05-0405
- ↑ Ma JL, Lee SJ, Duong JK, Stern DF. Activation of the checkpoint kinase Rad53 by the phosphatidyl inositol kinase-like kinase Mec1. J Biol Chem. 2006 Feb 17;281(7):3954-63. Epub 2005 Dec 19. PMID:16365046 doi:http://dx.doi.org/M507508200
- ↑ Tannous EA, Yates LA, Zhang X, Burgers PM. Mechanism of auto-inhibition and activation of Mec1(ATR) checkpoint kinase. Nat Struct Mol Biol. 2021 Jan;28(1):50-61. PMID:33169019 doi:10.1038/s41594-020-00522-0
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