PCNA-Dependent Cleavage and Degradation of SDE2 Regulates Response to Replication Stress

Jo, Ukhyun; Winson, Cai; Wang, Jingming; Yoojin, Kwon; D’Andrea, Alan D.; Kim, Hyungjin

doi:10.1371/journal.pgen.1006465

Cited by 33 publications

(47 citation statements)

References 58 publications

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“…PCNA is expressed in cell nuclei, and its expression is elevated in cells at S phase (the DNA synthesis phase of cell cycle) [39]. PCNA participates in the repair of DNA via resynthesis of excised damaged DNA strands [40][41][42]. Our data further illustrated a down-regulated expression of PCNA in RIZ1overexpressed tumours exposed to radiation.…”

Section: Discussionsupporting

confidence: 62%

Combination of RIZ1 Overexpression and Radiotherapy Contributes to Apoptosis and DNA Damage of HeLa and SiHa Cervical Cancer Cells

Yang

Xing

et al. 2018

Basic Clin Pharma Tox

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Although radiotherapy has been widely applied to treating cervical cancer in the clinic, its therapeutic efficacy is often restricted to the radioresistance of cancer cells. Retinoblastoma protein-interacting zinc finger gene 1 (RIZ1) has been suggested as a tumour suppressor gene, whereas its role in cervical cancer with or without radiotherapy has been unclear. In this study, two cervical cancer cell lines, HeLa and SiHa cells, stably transfected with RIZ1 overexpression plasmid were subjected to ionizing radiation, and their survival fractions were calculated by assessing their clonogenic abilities. Our results showed that the forced overexpression of RIZ1 significantly reduced the clonogenic survival rates of both HeLa and SiHa cells exposed to ionizing radiation. By analysing the cell apoptotic status, we found that the RIZ1-overexpressed cervical cancer cells under ionizing radiation were more vulnerable to damage, and more γ-H2AX foci were found in these cells. Furthermore, the volumes of tumour xenografts formed by the RIZ1-overexpressed cells in nude mice under ionizing radiation were smaller than those generated by the control cells. There were more morphological changes, apoptosis cells and lower expression of PCNA in RIZ1-overexpressed tumour tissues of mice after exposure to ionizing radiation. Taken together, our study demonstrates that the overexpression of RIZ1 combined with radiotherapy facilitates apoptosis and DNA damage of cervical cancer cells.

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Section: Discussionsupporting

confidence: 62%

Combination of RIZ1 Overexpression and Radiotherapy Contributes to Apoptosis and DNA Damage of HeLa and SiHa Cervical Cancer Cells

Yang

Xing

et al. 2018

Basic Clin Pharma Tox

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“…The intriguing activity of Ubp5 and Ubp15 to process two distant UBLs requires structural studies of Sde2 UBL ‐protease complexes to reveal the mechanism of catalysis. In support of conservation of Sde2 processing, Kim and colleagues have recently reported cleavage and degradation of human Sde2 in a PCNA‐dependent manner and its role in replication stress (Jo et al , ).…”

Section: Discussionmentioning

confidence: 95%

Sde2 is an intron‐specific pre‐ mRNA splicing regulator activated by ubiquitin‐like processing

et al. 2017

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The expression of intron-containing genes in eukaryotes requires generation of protein-coding messenger RNAs (mRNAs) via RNA splicing, whereby the spliceosome removes non-coding introns from pre-mRNAs and joins exons. Spliceosomes must ensure accurate removal of highly diverse introns. We show that Sde2 is a ubiquitin-fold-containing splicing regulator that supports splicing of selected pre-mRNAs in an intron-specific manner in Both fission yeast and human Sde2 are translated as inactive precursor proteins harbouring the ubiquitin-fold domain linked through an invariant GGKGG motif to a C-terminal domain (referred to as Sde2-C). Precursor processing after the first di-glycine motif by the ubiquitin-specific proteases Ubp5 and Ubp15 generates a short-lived activated Sde2-C fragment with an N-terminal lysine residue, which subsequently gets incorporated into spliceosomes. Absence of Sde2 or defects in Sde2 activation both result in inefficient excision of selected introns from a subset of pre-mRNAs. Sde2 facilitates spliceosomal association of Cactin/Cay1, with a functional link between Sde2 and Cactin further supported by genetic interactions and pre-mRNA splicing assays. These findings suggest that ubiquitin-like processing of Sde2 into a short-lived activated form may function as a checkpoint to ensure proper splicing of certain pre-mRNAs in fission yeast.

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“…We could also visualize specific PLA foci between PCNA and GFP-tagged SDE2, further supporting its association with replication forks (Figure 1D). The formation of SDE2-EdU PLA foci was dependent on the C-terminal SAP domain, which is required for DNA binding 34 (Figure S1A).…”

Section: Sde2 Is Localized At Active Dna Replication Forksmentioning

confidence: 99%

“…pcDNA3-SDE2-Flag and its mutants were previously described 34,35 . pcDNA4-Flag-TIMELESSmyc-6xHis and pcDNA3-Flag-TIPIN were a gift from Aziz Sancar (Addgene plasmids #22887 and #22889).…”

Section: Plasmid Constructionsmentioning

confidence: 99%

“…These findings indicate that the dynamic control of SDE2 protein levels may modulate protein complexes and their activities at stressed forks. Although a role of SDE2 in DNA replication and stalled fork recovery has been shown, the mechanism by which this occurs is unknown 34 . Here, we demonstrate that SDE2 directly interacts with the FPC component TIM and promotes TIM stability and its localization at replication forks.…”

Section: Introductionmentioning

confidence: 99%

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SDE2 Integrates into the TIMELESS-TIPIN Complex to Protect Stalled Replication Forks

Rageul

Park

Zeng

et al. 2020

Preprint

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Protecting replication fork integrity during DNA replication is essential for maintaining genome stability. Here, we report that SDE2, a PCNA-associated protein, plays a key role in maintaining active replication and counteracting replication stress by regulating the replication fork protection complex (FPC). SDE2 directly interacts with the FPC component TIMELESS (TIM) and enhances TIM stability and its localization to replication forks, thereby aiding the coordination of replisome progression. Like TIM deficiency, knockdown of SDE2 leads to impaired fork progression and stalled fork recovery, along with a failure to activate CHK1 phosphorylation. Moreover, loss of SDE2 or TIM results in an excessive MRE11-dependent degradation of reversed forks. Together, our study uncovers an essential role for SDE2 in maintaining genomic integrity by stabilizing the FPC and describes a new role for TIM in protecting stalled replication forks. We propose that TIM-mediated fork protection may represent a way to cooperate with BRCA-dependent fork stabilization. form a four-way junction by the action of the RAD51 recombinase and several SWI/SNF family translocases such as SMARCAL1, ZRANB3, and HLTF 14,15 . This unique transaction protects stressed forks from degradation and acts as an intermediate for the repair and restart of stalled forks [16][17][18] . The tumor suppressor proteins BRCA1/2 and Fanconi anemia (FA) protein FANCD2 are required for the protection of reversed forks by stabilizing the RAD51 filaments and preventing the regressed arm from nucleolytic degradation 19 . Many regulatory proteins fine-tune the steps of processing or protecting reversed forks, and deregulated fork remodeling has been associated with fork collapse, genome instability, and sensitivity or resistance to chemotherapy 20,21 .The fork protection complex (FPC), composed of TIMELESS (TIM) and TIPIN (Swi1 and Swi3 in S. pombe, and Tof1 and Csm3 in S. cerevisiae), and the ancillary proteins AND-1 and CLASPIN (CLSPN) stabilizes the replisome to ensure unperturbed fork progression [22][23][24] . The FPC acts as a scaffold to link the movements of the CMG helicase and polymerase, preventing the uncoupling of their activities and ensuring efficient replisome progression 25,26 . Additionally, the FPC promotes the ATR-CHK1 checkpoint signaling under replication stress by stimulating the association of TIM-TIPIN and CLSPN to RPA-ssDNA at stalled forks, thereby facilitating CLSPN-mediated CHK1 phosphorylation by ATR 27,28 . TIM and TIPIN form an obligate heterodimer and have no known enzymatic function, suggesting that they play a structural role in supporting replisome integrity 29 . Loss of the FPC leads to defects in DNA replication and genome instability, indicating that maintaining structural integrity of the replisome is critical for preserving fork stability [30][31][32] . TIM is upregulated in a variety of cancers, implying that enhanced FPC activity may alleviate replication stress arising in tumors through oncogene activation 33 . However, the regu...

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PCNA-Dependent Cleavage and Degradation of SDE2 Regulates Response to Replication Stress

Cited by 33 publications

References 58 publications

Combination of RIZ1 Overexpression and Radiotherapy Contributes to Apoptosis and DNA Damage of HeLa and SiHa Cervical Cancer Cells

Combination of RIZ1 Overexpression and Radiotherapy Contributes to Apoptosis and DNA Damage of HeLa and SiHa Cervical Cancer Cells

Sde2 is an intron‐specific pre‐ mRNA splicing regulator activated by ubiquitin‐like processing

SDE2 Integrates into the TIMELESS-TIPIN Complex to Protect Stalled Replication Forks

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