The proteasomal de-ubiquitinating enzyme POH1 promotes the double-strand DNA break response

Butler, Laura; Densham, Ruth M; Jia, Junying; Garvin, Alexander J; Stone, Helen R; Shah, Vandna; Weekes, Daniel; Festy, Frederic; Beesley, James; Morris, Joanna R.

doi:10.1038/emboj.2012.232

Cited by 134 publications

(154 citation statements)

References 94 publications

Supporting

Mentioning

149

Contrasting

Order By: Relevance

“…Several studies reported the screening of genes in regulating the recruitment of 53BP1 to DNA damage sites (38)(39)(40). Depletion of UbcH7 was reported to increase the size of 53BP1 foci (30), similar to our observation.…”

Section: Discussionsupporting

confidence: 81%

UbcH7 regulates 53BP1 stability and DSB repair

Han¹,

Zhang²,

Chung³

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

DNA double-strand break (DSB) repair is not only key to genome stability but is also an important anticancer target. Through an shRNA library-based screening, we identified ubiquitin-conjugating enzyme H7 (UbcH7, also known as Ube2L3), a ubiquitin E2 enzyme, as a critical player in DSB repair. UbcH7 regulates both the steady-state and replicative stress-induced ubiquitination and proteasome-dependent degradation of the tumor suppressor p53-binding protein 1 (53BP1). Phosphorylation of 53BP1 at the N terminus is involved in the replicative stress-induced 53BP1 degradation. Depletion of UbcH7 stabilizes 53BP1, leading to inhibition of DSB end resection. Therefore, UbcH7-depleted cells display increased nonhomologous end-joining and reduced homologous recombination for DSB repair. Accordingly, UbcH7-depleted cells are sensitive to DNA damage likely because they mainly used the errorprone nonhomologous end-joining pathway to repair DSBs. Our studies reveal a novel layer of regulation of the DSB repair choice and propose an innovative approach to enhance the effect of radiotherapy or chemotherapy through stabilizing 53BP1.DNA damage response | UbcH7 | 53BP1 | protein degradation | DSB repair P rompt response to double-strand breaks (DSBs) caused by, for example, ionization radiation (IR), requires sequential and coordinated assembly of DNA damage response (DDR) proteins at damage sites (1). Recent research findings reveal key roles of the tumor suppressor p53-binding protein 1 (53BP1) and BRCA1 in the decision making of DSB repair. 53BP1, together with Rif1, suppress BRCA1-dependent homologous recombination (HR), thereby promoting nonhomologous end-joining (NHEJ) in G1 phase (2-6). Conversely, BRCA1 antagonizes 53BP1/Rif1, favoring HR in S and G2 phases (7,8). In the absence of BRCA1 or with enhanced retention of 53BP1 at DSB sites, cells primarily use the error-prone NHEJ to repair DSBs throughout the cell cycle, which leads to gene rearrangement, cell death, and increased sensitivity to anticancer therapies (9-11). Consistently, BRCA1-null mice are early embryonic lethal (12, 13) and codepletion of TP53BP1 rescued the lethality phenotype of BRCA1-null mice (12)(13)(14).Low expression level of 53BP1 was found to be associated with poor clinical outcome in triple negative breast cancer patients with BRCA1 mutation (12, 15), as well as resistance to genotoxins and poly(ADP-ribose) polymerase inhibitors (12,16,17). This finding is probably because loss of 53BP1 restored HR and promoted cell survival (12-14). Reduced expression of 53BP1 was also observed in tumors from the brain (18), lymph node (19), and pancreas (20). These data indicate that loss of 53BP1 might be a common mechanism for advanced tumors to evade from radiotherapy or chemotherapy. However, molecular mechanisms controlling the protein level of 53BP1 remain less well understood.Here we show that UbcH7, an E2 enzyme involved in the ubiquitin (Ub) pathway, controls the protein stability of 53BP1, thereby determining the DSB repair choice. Loss of UbcH7 sta...

show abstract

Section: Discussionsupporting

confidence: 81%

UbcH7 regulates 53BP1 stability and DSB repair

Han¹,

Zhang²,

Chung³

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

show abstract

“…37 POH1, a deubiquitylating enzyme (DUB) and proteasome component, has been proposed to influence 53BP1 IRIF size in G1 by regulating RNF8/168-dependent ubiquitination and JMJD2 chromatin retention. 57 Strikingly, we found that depletion of POH1, like siBRCA1, precluded the formation of a 53BP1-devoid core in the IRIF and RPA foci formation and that combined depletion of POH1 and RAP80 restored the bimodal distribution as well as RPA foci. 37 These findings demonstrate that 53BP1 and RAP80 provide barriers to resection, which are relieved by BRCA1 and POH1, respectively (Figure 3).…”

Section: Poh1 Relieves a Barrier That Receptor-associated Protein 80mentioning

confidence: 82%

DNA DSB repair pathway choice: an orchestrated handover mechanism

Kakarougkas

Jeggo²

2014

BJR

231

186

View full text Add to dashboard Cite

Cite this article as: Kakarougkas A, Jeggo PA. DNA DSB repair pathway choice: an orchestrated handover mechanism. Br J Radiol 2014;87:20130685. RADIOBIOLOGY SPECIAL FEATURE: REVIEW ARTICLE DNA DSB repair pathway choice: an orchestrated handover mechanism A KAKAROUGKAS, MSc, PhD, and P A JEGGO, PhD Genome Damage and Stability Centre, University of Sussex, Brighton, UK Address correspondence to: Professor Penny Jeggo E-mail: p.a.jeggo@sussex.ac.uk ABSTRACT DNA double strand breaks (DSBs) are potential lethal lesions but can also lead to chromosome rearrangements, a step promoting carcinogenesis. DNA non-homologous end-joining (NHEJ) is the major DSB rejoining process and occurs in all cell cycle stages. Homologous recombination (HR) can additionally function to repair irradiation-induced two-ended DSBs in G2 phase. In mammalian cells, HR predominantly uses a sister chromatid as a template for DSB repair; thus HR functions only in late S/G2 phase. Here, we review current insight into the interplay between HR and NHEJ in G2 phase. We argue that NHEJ represents the first choice pathway, repairing approximately 80% of X-ray-induced DSBs with rapid kinetics. However, a subset of DSBs undergoes end resection and repair by HR. 53BP1 restricts resection, thereby promoting NHEJ. During the switch from NHEJ to HR, 53BP1 is repositioned to the periphery of enlarged irradiation-induced foci (IRIF) via a BRCA1-dependent process. K63-linked ubiquitin chains, which also form at IRIF, are also repositioned as well as receptor-associated protein 80 (RAP80), a ubiquitin binding protein. RAP80 repositioning requires POH1, a proteasome component. Thus, the interfacing barriers to HR, 53BP1 and RAP80 are relieved by POH1 and BRCA1, respectively. Removal of RAP80 from the IRIF core is required for loss of the ubiquitin chains and 53BP1, and for efficient replication protein A foci formation. We propose that NHEJ is used preferentially to HR because it is a compact process that does not necessitate extensive chromatin changes in the DSB vicinity.

show abstract

“…1C and Table S1). As proof of validity, we also identified BRCC36, USP3, and PSMD14, which have been previously reported to regulate DSB signaling by impacting RAD51 and/or BRCA1 foci formation (9,10,16). The DUB candidates whose knockdown induced a decrease in BRCA1/RAD51 foci formation include BAP1, DUB3, STAMBP, STAMBPL1, and COPS5 (Fig.…”

Section: Dub Rnai Screen Reveals Several Regulators Of Hr Proteins Asmentioning

confidence: 92%

“…For instance, BRCA1/BRCA2-containing complex subunit 36 (BRCC36), a K63 chain-specific DUB, regulates the recruitment of repair proteins by modulating the level of ubiquitin chains (7,8). POH1/rpn11/PSMD14, a regulatory subunit of the 19S proteasome, deconjugates ubiquitin chains at DSB sites and promotes the recruitment of RAD51 (9). Ubiquitin specific peptidase 3 (USP3) and OTUB1 have also been reported to be important for DSB signaling and repair (10,11).…”

mentioning

confidence: 99%

Tumor suppressor and deubiquitinase BAP1 promotes DNA double-strand break repair

Pak

Hammond-Martel

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

306

339

View full text Add to dashboard Cite

The cellular response to highly genotoxic DNA double-strand breaks (DSBs) involves the exquisite coordination of multiple signaling and repair factors. Here, we conducted a functional RNAi screen and identified BAP1 as a deubiquitinase required for efficient assembly of the homologous recombination (HR) factors BRCA1 and RAD51 at ionizing radiation (IR) -induced foci. BAP1 is a chromatin-associated protein frequently inactivated in cancers of various tissues. To further investigate the role of BAP1 in DSB repair, we used a gene targeting approach to knockout (KO) this deubiquitinase in chicken DT40 cells. We show that BAP1-deficient cells are (i) sensitive to IR and other agents that induce DSBs, (ii) defective in HR-mediated immunoglobulin gene conversion, and (iii) exhibit an increased frequency of chromosomal breaks after IR treatment. We also show that BAP1 is recruited to chromatin in the proximity of a single site-specific I-SceI-induced DSB. Finally, we identified six IR-induced phosphorylation sites in BAP1 and showed that mutation of these residues inhibits BAP1 recruitment to DSB sites. We also found that both BAP1 catalytic activity and its phosphorylation are critical for promoting DNA repair and cellular recovery from DNA damage. Our data reveal an important role for BAP1 in DSB repair by HR, thereby providing a possible molecular basis for its tumor suppressor function.

show abstract

The proteasomal de-ubiquitinating enzyme POH1 promotes the double-strand DNA break response

Cited by 134 publications

References 94 publications

UbcH7 regulates 53BP1 stability and DSB repair

UbcH7 regulates 53BP1 stability and DSB repair

DNA DSB repair pathway choice: an orchestrated handover mechanism

Tumor suppressor and deubiquitinase BAP1 promotes DNA double-strand break repair

Contact Info

Product

Resources

About