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-Structure paper
Title | Mechanism of auto-inhibition and activation of Mec1 checkpoint kinase. |
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Journal, issue, pages | Nat Struct Mol Biol, Vol. 28, Issue 1, Page 50-61, Year 2021 |
Publish date | Nov 9, 2020 |
![]() | Elias A Tannous / Luke A Yates / Xiaodong Zhang / Peter M Burgers / ![]() ![]() |
PubMed Abstract | In response to DNA damage or replication fork stalling, the basal activity of Mec1 is stimulated in a cell-cycle-dependent manner, leading to cell-cycle arrest and the promotion of DNA repair. Mec1 ...In response to DNA damage or replication fork stalling, the basal activity of Mec1 is stimulated in a cell-cycle-dependent manner, leading to cell-cycle arrest and the promotion of DNA repair. Mec1 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 Å and the wild type at 3.8 Å, both in complex with Mg-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. |
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Methods | EM (single particle) |
Resolution | 2.82 - 4.3 Å |
Structure data | EMDB-11050, PDB-6z2w: EMDB-11051, PDB-6z2x: EMDB-11055, PDB-6z3a: ![]() EMDB-11056: |
Chemicals | ![]() ChemComp-ANP: ![]() ChemComp-ZN: ![]() ChemComp-MG: ![]() ChemComp-HOH: |
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