The Human Tim-Tipin Complex Interacts Directly with DNA Polymerase ϵ and Stimulates Its Synthetic Activity

Aria, Valentina; Felice, Maurilio De; Perna, Roberta Di; Uno, Shuji; Masai, Hisao; Syväoja, Juhani E.; Loon, Barbara van; Hübscher, Ulrich; Pisani, Francesca M.

doi:10.1074/jbc.m112.398073

Cited by 17 publications

(21 citation statements)

References 40 publications

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“…Replisome components are usually stably associated to replication forks 27 . Tipin is required for efficient Pol α binding to chromatin, and it has been shown to increase processivity of all major DNA polymerases 3 , 8 . It is possible that the Tipin facilitates polymerase-mediated DNA replication re-priming, ensuring discontinuous progression of DNA replication.…”

Section: Discussionmentioning

confidence: 99%

Mta2 promotes Tipin-dependent maintenance of replication fork integrity

Errico¹,

Aze²,

Costanzo

2014

Cell Cycle

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Orderly progression of S phase requires the action of replisome-associated Tipin and Tim1 proteins, whose molecular function is poorly understood. Here, we show that Tipin deficiency leads to the accumulation of aberrant replication intermediates known as reversed forks. We identified Mta2, a subunit of the NuRD chromatin remodeler complex, as a novel Tipin binding partner and mediator of its function. Mta2 is required for Tipin-dependent Polymerase α binding to replicating chromatin, and this function is essential to prevent the accumulation of reversed forks. Given the role of the Mta2–NuRD complex in the maintenance of heterochromatin, which is usually associated with hard-to-replicate DNA sequences, we tested the role of Tipin in the replication of such regions. Using a novel assay we developed to monitor replication of specific genomic loci in Xenopus laevis egg extract we demonstrated that Tipin is directly required for efficient replication of vertebrate centromeric DNA. Overall these results suggest that Mta2 and Tipin cooperate to maintain replication fork integrity, especially on regions that are intrinsically difficult to duplicate.

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Section: Discussionmentioning

confidence: 99%

Mta2 promotes Tipin-dependent maintenance of replication fork integrity

Errico¹,

Aze²,

Costanzo

2014

Cell Cycle

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“…Several kinases have been reported to phosphorylate CLASPIN and promote CHK1 activation, including CHK1 itself (4)(5)(6)14), casein kinase 1 gamma 1 (CK1g1; ref. 15), and CDC7 (16,17).…”

Section: Introductionmentioning

confidence: 99%

“…Importantly, cellular surveillance mechanisms that overlap with the DNA damage response pathways detect, stabilize, and resolve stalled replication forks to help preserve genome stability (2). CLASPIN, critical for both DNA synthesis and for signaling the presence of replication stress, is a ring-shaped protein that, together with the TIPIN-TIM1 complex, physically links DNA polymerases and DNA helicase (4)(5)(6); this is important for stabilization of replication forks, both during normal replication and upon prolonged arrest (1,2,7). CLASPIN also plays an important role in the replication stress response pathway (3,8,9), as ATR activation of CHK1 is favored by the binding of CHK1 to CLASPIN (2,(10)(11)(12)(13).…”

Section: Introductionmentioning

confidence: 99%

The Deubiquitinase USP9X Maintains DNA Replication Fork Stability and DNA Damage Checkpoint Responses by Regulating CLASPIN during S-Phase

et al. 2016

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Coordination of the multiple processes underlying DNA replication is key for maintaining genome stability and preventing tumorigenesis. CLASPIN, a critical player in replication fork stabilization and checkpoint responses, must be tightly regulated during the cell cycle to prevent the accumulation of DNA damage. In this study, we used a quantitative proteomics approach and identified USP9X as a novel CLASPIN-interacting protein. USP9X is a deubiquitinase involved in multiple signaling and survival pathways whose tumor suppressor or oncogenic activity is highly context dependent. We found that USP9X regulated the expression and stability of CLASPIN in an S-phase-specific manner. USP9X depletion profoundly impairs the progression of DNA replication forks, causing unscheduled termination events with a frequency similar to CLASPIN depletion, resulting in excessive endogenous DNA damage. Importantly, restoration of CLASPIN expression in USP9X-depleted cells partially suppressed the accumulation of DNA damage. Furthermore, USP9X depletion compromised CHK1 activation in response to hydroxyurea and UV, thus promoting hypersensitivity to drug-induced replication stress. Taken together, our results reveal a novel role for USP9X in the maintenance of genomic stability during DNA replication and provide potential mechanistic insights into its tumor suppressor role in certain malignancies. Cancer Res; 76(8); 2384-93. Ó2016 AACR.

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“…This is very slow, considering that estimates suggest that entire Okazaki fragments are synthesized and processed in under 1 s (57, 58). The loading of Pol ⑀ might be faster in vivo due to the activities of other proteins, such as GINS in the preloading complex/CMG helicase in yeast and TIM-Tipin in human cells (25,59,60). Recent in vitro reconstitution experiments showed that CMG helicase selects Pol ⑀ over Pol ␦ on the leading strand in yeast (61).…”

mentioning

confidence: 99%

Yeast DNA Polymerase ϵ Catalytic Core and Holoenzyme Have Comparable Catalytic Rates

Ganai

Osterman

Johansson

2015

Journal of Biological Chemistry

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Background:The catalytic rates for yeast Pol ⑀ are unknown. Results: The catalytic core and holoenzyme have comparable catalytic rates, but the loading onto primer termini differs. Conclusion:The accessory subunits and C terminus of the catalytic subunit do not influence the catalytic rates. Significance: The catalytic rates of Pol ⑀ provide a benchmark for future mechanistic studies of leading strand synthesis.

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The Human Tim-Tipin Complex Interacts Directly with DNA Polymerase ϵ and Stimulates Its Synthetic Activity

Cited by 17 publications

References 40 publications

Mta2 promotes Tipin-dependent maintenance of replication fork integrity

Mta2 promotes Tipin-dependent maintenance of replication fork integrity

The Deubiquitinase USP9X Maintains DNA Replication Fork Stability and DNA Damage Checkpoint Responses by Regulating CLASPIN during S-Phase

Yeast DNA Polymerase ϵ Catalytic Core and Holoenzyme Have Comparable Catalytic Rates

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