Phosphorylation of Sae2 Mediates Forkhead-associated (FHA) Domain-specific Interaction and Regulates Its DNA Repair Function

Liang, Jason; Suhandynata, Raymond T.; Zhou, Huilin

doi:10.1074/jbc.m114.625293

Cited by 33 publications

(45 citation statements)

References 44 publications

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“…Previous studies have shown that Xrs2/Nbs1 is a flexible scaffold that binds to several DNA repair proteins, including Mre11, Tel1/ATM, Sae2/Ctp1/CtIP and Lif1 (Liang et al, 2015; Lloyd et al, 2009; Matsuzaki et al, 2008; Nakada et al, 2003; Palmbos et al, 2008; Tsukamoto et al, 2005; Williams et al, 2009). Xrs2 binding to Mre11 is required for its nuclear localization raising the question of the contribution of Xrs2 to MR functions once the complex is in the correct cellular compartment.…”

Section: Discussionmentioning

confidence: 99%

“…Deletion of the Tel1 interaction motif at the C-terminus of Xrs2 ( xrs2-11 ) results in a phenotype similar to the tel1Δ mutant, including a defect in DNA damage signaling and short telomeres (Nakada et al, 2003). The N-terminal region of Xrs2/Nbs1 contains a forkhead associated (FHA) domain, which binds to phosphorylated Sae2/Ctp1/CtIP and Lif1/Xrcc4 (Chen et al, 2001; Liang et al, 2015; Lloyd et al, 2009; Matsuzaki et al, 2008; Palmbos et al, 2008; Wang et al, 2013; Williams et al, 2009). …”

Section: Introductionmentioning

confidence: 99%

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Xrs2 Dependent and Independent Functions of the Mre11-Rad50 Complex

Al-Zain

Cannavó

et al. 2016

Molecular Cell

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SUMMARY The Mre11-Rad50-Xrs2/Nbs1 (MRX/N) complex orchestrates the cellular response to DSBs through its structural, enzymatic and signaling roles. Xrs2/Nbs1 is essential for nuclear translocation of Mre11, but its role as a component of the complex is not well defined. Here we demonstrate that nuclear localization of Mre11 (Mre11-NLS) is able to bypass several functions of Xrs2, including DNA end resection, meiosis, hairpin resolution and cellular resistance to clastogens. Using purified components, we show the MR complex has equivalent activity to MRX in cleavage of protein-blocked DNA ends. Although Xrs2 physically interacts with Sae2, we found that end resection in its absence remains Sae2 dependent in vivo and in vitro. MRE11-NLS was unable to rescue the xrs2Δ defects in Tel1/ATM kinase signaling and non-homologous end joining, consistent with the role of Xrs2 as a chaperone and adaptor protein coordinating interactions between the MR complex and other repair proteins.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Xrs2 Dependent and Independent Functions of the Mre11-Rad50 Complex

Al-Zain

Cannavó

et al. 2016

Molecular Cell

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“…The substitution with alanine of five of the Sae2 S/TQ sites, which conform to the consensus phosphorylation motif of Mec1 and Tel1, prevents DNA damage-dependent phosphorylation and the sae2-5A mutant is phenotypically similar to sae2Δ (Baroni et al, 2004). Phosphorylation of Thr-90 of Sae2 mediates interaction with the FHA domains of Xrs2, Rad53 and Dun1, whereas Rad53 and Dun1 additionally interact with phosphorylated Thr-279 (Liang, Suhandynata, and Zhou, 2015). The sae2-2AQ mutant (T90A, T279A) is more resistant to DNA damaging agents than sae2Δ and sae2-5A , but exhibits prolonged Rad53 activation, similar to the sae2Δ mutant.…”

Section: Resection and The Dna Damage Checkpointmentioning

confidence: 99%

Mechanism and regulation of DNA end resection in eukaryotes

Symington

2016

Critical Reviews in Biochemistry and Molecular Biology

355

402

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The repair of DNA double-strand breaks (DSBs) by homologous recombination (HR) is initiated by nucleolytic degradation of the 5′ terminated strands in a process termed end resection. End resection generates 3′ single-stranded DNA tails, substrates for Rad51 to catalyze homologous pairing and exchange of DNA strands, and for activation of the DNA damage checkpoint. The commonly accepted view is that end resection occurs by a two-step mechanism. In the first step, Sae2/CtIP activates the Mre11-Rad50-Xrs2/Nbs1 (MRX/N) complex to endonucleolytically cleave the 5′-terminated DNA strands close to break ends, and in the second step Exo1 and/or Dna2 nucleases extend the resected tracts to produce long 3′-ssDNA-tailed intermediates. Initiation of resection commits a cell to repair a DSB by HR because long ssDNA overhangs are poor substrates for non-homologous end joining (NHEJ). Thus, the initiation of end resection has emerged as a critical control point for repair pathway choice. Here, I review recent studies on the mechanism of end resection and how this process is regulated to ensure the most appropriate repair outcome.

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“…Phosphorylation of Sae2 was shown to affect its oligomeric state (63). Furthermore, mutations of Mec1/Tel1 target sites to non-phosphorylatable residues in Sae2 result in DNA damage sensitivity, showing that in addition, phosphorylation under the control of DNA damage checkpoint is important for the function of Sae2 in vivo (63)(64)(65). As Sae2 has additional roles on top of controlling Mre11 (see above), it remains to be determined whether the Mec1/Tel1-dependent phosphorylation affects DSB resection or other functions of Sae2.…”

Section: Short-range Dna End Processing By Mrx and Sae2: Mechanism Anmentioning

confidence: 99%

“…Therefore, the CDKdependent regulation of Sae2 activity represents one of the key control mechanisms ensuring that resection only takes place in the S/G 2 phase of the cell cycle when a homologous template is available for repair. In addition to CDK, Sae2 is also regulated by the Mec1 and Tel1 kinases in response to DNA damage (63)(64)(65). Phosphorylation of Sae2 was shown to affect its oligomeric state (63).…”

Section: Short-range Dna End Processing By Mrx and Sae2: Mechanism Anmentioning

confidence: 99%

DNA End Resection: Nucleases Team Up with the Right Partners to Initiate Homologous Recombination

Ćejka

2015

Journal of Biological Chemistry

189

199

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The repair of DNA double-strand breaks by homologous recombination commences by nucleolytic degradation of the 5-terminated strand of the DNA break. This leads to the formation of 3-tailed DNA, which serves as a substrate for the strand exchange protein Rad51. The nucleoprotein filament then invades homologous DNA to drive template-directed repair. In this review, I discuss mainly the mechanisms of DNA end resection in Saccharomyces cerevisiae, which includes short-range resection by Mre11-Rad50-Xrs2 and Sae2, as well as processive long-range resection by Sgs1-Dna2 or Exo1 pathways. Resection mechanisms are highly conserved between yeast and humans, and analogous machineries are found in prokaryotes as well. Homologous recombination (HR)2 plays a central role in the repair of DNA double-strand breaks (DSBs) (1). In vegetative cells, recombination restores broken DNA to preserve genome integrity. In meiosis, HR promotes proper chromosome segregation and exchange of genetic information between maternal and paternal genomes, and thus contributes to the generation of genetic diversity. Recombination is initiated upon the formation of ssDNA overhangs through a process termed DNA end resection. The nucleolytic processing of broken DNA ends is essential for all recombination mechanisms (Fig. 1). Resection of DSBs commits their repair to HR as it prevents ligation by the potentially more mutagenic non-homologous end-joining (NHEJ) pathway (2-4). Resected DNA is first coated by the ssDNA-binding protein replication protein A (RPA). In most cases, RPA is subsequently replaced with the strand exchange protein Rad51, forming a nucleoprotein filament capable of invading homologous DNA. Repair can then proceed via either of two main recombination pathways, synthesis-dependent strand annealing or the canonical pathway that involves the formation of a double Holliday junction (Fig. 1). Single-strand annealing (SSA) is instead a Rad51-independent pathway that requires extensive resection of DNA between two repetitive sequences ( Fig. 1). DNA End Resection: When and What to ResectDSBs can form accidentally in any phase of the cell cycle upon exposure to ionizing radiation or chemicals or as a result of abortive processing of nucleic acids. Most DSBs, however, occur in S-phase when a DNA replication fork runs into a nick. Furthermore, DSBs are sometimes introduced "intentionally," such as in the prophase of the first meiotic division or during anticancer therapy regimens based on DNA-damaging agents (5). Depending on the cellular context, cells must first "decide" whether or not to resect the breaks (3, 4, 6, 7). DNA end resection commits the repair to HR and prevents NHEJ; therefore, it would be detrimental to resect DSBs in the G 1 phase of the cell cycle when no sister chromatid DNA is available as a template for repair. Cells have thus developed regulatory control mechanisms that activate resection only during the S or G 2 phases of the cell cycle, which will be introduced below (4, 6 -8).Another critical parameter is the pola...

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Phosphorylation of Sae2 Mediates Forkhead-associated (FHA) Domain-specific Interaction and Regulates Its DNA Repair Function

Cited by 33 publications

References 44 publications

Xrs2 Dependent and Independent Functions of the Mre11-Rad50 Complex

Xrs2 Dependent and Independent Functions of the Mre11-Rad50 Complex

Mechanism and regulation of DNA end resection in eukaryotes

DNA End Resection: Nucleases Team Up with the Right Partners to Initiate Homologous Recombination

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