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Tapia-Alveal C, Lin SJ, O’Connell MJ. Functional interplay between cohesin and Smc5/6 complexes. Chromosoma 2014; 123:437-45. [PMID: 24981336 PMCID: PMC4169997 DOI: 10.1007/s00412-014-0474-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Revised: 06/10/2014] [Accepted: 06/11/2014] [Indexed: 12/14/2022]
Abstract
Chromosomes are subjected to massive reengineering as they are replicated, transcribed, repaired, condensed, and segregated into daughter cells. Among the engineers are three large protein complexes collectively known as the structural maintenance of chromosome (SMC) complexes: cohesin, condensin, and Smc5/6. As their names suggest, cohesin controls sister chromatid cohesion, condensin controls chromosome condensation, and while precise functions for Smc5/6 have remained somewhat elusive, most reports have focused on the control of recombinational DNA repair. Here, we focus on cohesin and Smc5/6 function. It is becoming increasingly clear that the functional repertoires of these complexes are greater than sister chromatid cohesion and recombination. These SMC complexes are emerging as interrelated and cooperating factors that control chromosome dynamics throughout interphase. However, they also release their embrace of sister chromatids to enable their segregation at anaphase, resetting the dynamic cycle of SMC-chromosome interactions.
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Affiliation(s)
- Claudia Tapia-Alveal
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Su-Jiun Lin
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Matthew J. O’Connell
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY
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SUMO-targeted ubiquitin ligase, Rad60, and Nse2 SUMO ligase suppress spontaneous Top1-mediated DNA damage and genome instability. PLoS Genet 2011; 7:e1001320. [PMID: 21408210 PMCID: PMC3048374 DOI: 10.1371/journal.pgen.1001320] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2010] [Accepted: 01/26/2011] [Indexed: 11/19/2022] Open
Abstract
Through as yet undefined proteins and pathways, the SUMO-targeted ubiquitin ligase (STUbL) suppresses genomic instability by ubiquitinating SUMO conjugated proteins and driving their proteasomal destruction. Here, we identify a critical function for fission yeast STUbL in suppressing spontaneous and chemically induced topoisomerase I (Top1)-mediated DNA damage. Strikingly, cells with reduced STUbL activity are dependent on tyrosyl-DNA phosphodiesterase 1 (Tdp1). This is notable, as cells lacking Tdp1 are largely aphenotypic in the vegetative cell cycle due to the existence of alternative pathways for the removal of covalent Top1-DNA adducts (Top1cc). We further identify Rad60, a SUMO mimetic and STUbL-interacting protein, and the SUMO E3 ligase Nse2 as critical Top1cc repair factors in cells lacking Tdp1. Detection of Top1ccs using chromatin immunoprecipitation and quantitative PCR shows that they are elevated in cells lacking Tdp1 and STUbL, Rad60, or Nse2 SUMO ligase activity. These unrepaired Top1ccs are shown to cause DNA damage, hyper-recombination, and checkpoint-mediated cell cycle arrest. We further determine that Tdp1 and the nucleotide excision repair endonuclease Rad16-Swi10 initiate the major Top1cc repair pathways of fission yeast. Tdp1-based repair is the predominant activity outside S phase, likely acting on transcription-coupled Top1cc. Epistasis analyses suggest that STUbL, Rad60, and Nse2 facilitate the Rad16-Swi10 pathway, parallel to Tdp1. Collectively, these results reveal a unified role for STUbL, Rad60, and Nse2 in protecting genome stability against spontaneous Top1-mediated DNA damage.
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Smet-Nocca C, Wieruszeski JM, Léger H, Eilebrecht S, Benecke A. SUMO-1 regulates the conformational dynamics of thymine-DNA Glycosylase regulatory domain and competes with its DNA binding activity. BMC BIOCHEMISTRY 2011; 12:4. [PMID: 21284855 PMCID: PMC3040724 DOI: 10.1186/1471-2091-12-4] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/07/2010] [Accepted: 02/01/2011] [Indexed: 12/01/2022]
Abstract
Background The human thymine-DNA glycosylase (TDG) plays a dual role in base excision repair of G:U/T mismatches and in transcription. Regulation of TDG activity by SUMO-1 conjugation was shown to act on both functions. Furthermore, TDG can interact with SUMO-1 in a non-covalent manner. Results Using NMR spectroscopy we have determined distinct conformational changes in TDG upon either covalent sumoylation on lysine 330 or intermolecular SUMO-1 binding through a unique SUMO-binding motif (SBM) localized in the C-terminal region of TDG. The non-covalent SUMO-1 binding induces a conformational change of the TDG amino-terminal regulatory domain (RD). Such conformational dynamics do not exist with covalent SUMO-1 attachment and could potentially play a broader role in the regulation of TDG functions for instance during transcription. Both covalent and non-covalent processes activate TDG G:U repair similarly. Surprisingly, despite a dissociation of the SBM/SUMO-1 complex in presence of a DNA substrate, SUMO-1 preserves its ability to stimulate TDG activity indicating that the non-covalent interactions are not directly involved in the regulation of TDG activity. SUMO-1 instead acts, as demonstrated here, indirectly by competing with the regulatory domain of TDG for DNA binding. Conclusions SUMO-1 increases the enzymatic turnover of TDG by overcoming the product-inhibition of TDG on apurinic sites. The mechanism involves a competitive DNA binding activity of SUMO-1 towards the regulatory domain of TDG. This mechanism might be a general feature of SUMO-1 regulation of other DNA-bound factors such as transcription regulatory proteins.
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Affiliation(s)
- Caroline Smet-Nocca
- Institut de Recherche Interdisciplinaire, Université de Lille1 - Université de Lille2 - CNRS USR3078, Parc de la Haute Borne, 50 avenue de Halley, 59658 Villeneuve d'Ascq, France
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Ku B, Lim JH, Shin HC, Shin SY, Oh BH. Crystal structure of the MukB hinge domain with coiled-coil stretches and its functional implications. Proteins 2009; 78:1483-90. [DOI: 10.1002/prot.22664] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Duan X, Yang Y, Chen YH, Arenz J, Rangi GK, Zhao X, Ye H. Architecture of the Smc5/6 Complex of Saccharomyces cerevisiae Reveals a Unique Interaction between the Nse5-6 Subcomplex and the Hinge Regions of Smc5 and Smc6. J Biol Chem 2009; 284:8507-15. [PMID: 19141609 PMCID: PMC2659209 DOI: 10.1074/jbc.m809139200] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2008] [Revised: 01/12/2009] [Indexed: 12/23/2022] Open
Abstract
The evolutionarily conserved structural maintenance of chromosome (SMC) proteins forms the core structures of three multisubunit complexes as follows: cohesin, condensin, and the Smc5/6 complex. These complexes play crucial roles in different aspects of chromosomal organization, duplication, and segregation. Although the architectures of cohesin and condensin are better understood, that of the more recently identified Smc5/6 complex remains to be elucidated. We have previously shown that the Smc5/6 complex of Saccharomyces cerevisiae contains Smc5, Smc6, and six non-SMC elements (Nse1-6). In this study, we investigated the architecture of the budding yeast Smc5/6 complex employing the yeast two-hybrid assay as well as in vitro biochemical approaches using purified recombinant proteins. These analyses revealed that Smc5 and Smc6 associate with each other at their hinge regions and constitute the backbone of the complex, whereas the Nse1-6 subunits form three distinct subcomplexes/entities that interact with different regions of Smc5 and Smc6. The Nse1, -3, and -4 subunits form a stable subcomplex that binds to the head and the adjacent coiled-coil region of Smc5. Nse2 binds to the middle of the coiled-coil region of Smc5. Nse5 and Nse6 interact with each other and, as a heterodimer, bind to the hinge regions of Smc5 and Smc6. These findings provide new insights into the structures of the Smc5/6 complex and lay the foundation for further investigations into the mechanism of its functions.
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Affiliation(s)
- Xinyuan Duan
- Brown Cancer Center, University of Louisville School of Medicine, Louisville, Kentucky 40202, USA
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Abstract
SUMO proteins are small ubiquitin-like modifiers found in all eukaryotes that become covalently conjugated to other cellular proteins. The SUMO conjugation pathway is biochemically similar to ubiquitin conjugation, although the enzymes within the pathway act exclusively on SUMO proteins. This post-translational modification controls many processes. Here, I will focus on evidence that SUMOylation plays a critical role(s) in mitosis: Early studies showed a genetic requirement for SUMO pathway components in the process of cell division, while later findings implicated SUMOylation in the control of mitotic chromosome structure, cell cycle progression, kinetochore function and cytokinesis. Recent insights into the targets of SUMOylation are likely to be extremely helpful in understanding each of these aspects. Finally, growing evidence suggests that SUMOylation is a downstream target of regulation through Ran, a small GTPase with important functions in both interphase nuclear trafficking and mitotic spindle assembly.
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Affiliation(s)
- Mary Dasso
- Laboratory of Gene Regulation and Development, NICHD/NIH, Building 18, Room 106, MSC-5431, Bethesda, MD 20892, USA.
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Wu F, Chiocca S, Beck WT, Mo YY. Gam1-associated alterations of drug responsiveness through activation of apoptosis. Mol Cancer Ther 2007; 6:1823-30. [PMID: 17575111 DOI: 10.1158/1535-7163.mct-06-0771] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
An early gene product, Gam1, encoded by the avian adenovirus CELO, is an inhibitory protein for the sumoylation machinery, which has been implicated in regulating a variety of cellular pathways. In this study, we found that Gam1 effectively suppressed both constitutive and inducible sumoylation and caused significant cell growth inhibition. This Gam1-mediated cell growth inhibition was associated with induction of apoptosis. In particular, Gam1 induced caspase-3 activity as detected by immunostaining and Western blot. Of interest, like the Ubc9 dominant-negative mutant, Gam1 also sensitized cells to DNA-damaging agents such as topotecan and doxorubicin and non-DNA-damaging agents such as paclitaxel and vincristine. Taken together, our findings suggest that activation of the caspase pathways is at least in part responsible for the increased apoptosis in Gam1-expressing cells and, thus, contributes to the growth inhibition and enhanced chemosensitivity.
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Affiliation(s)
- Fangting Wu
- Department of Medical Microbiology, Southern Illinois University School of Medicine, Springfield, IL 62794, USA
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Potts PR, Yu H. The SMC5/6 complex maintains telomere length in ALT cancer cells through SUMOylation of telomere-binding proteins. Nat Struct Mol Biol 2007; 14:581-90. [PMID: 17589526 DOI: 10.1038/nsmb1259] [Citation(s) in RCA: 284] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2007] [Accepted: 05/02/2007] [Indexed: 11/08/2022]
Abstract
Most cancer cells activate telomerase to elongate telomeres and achieve unlimited replicative potential. Some cancer cells cannot activate telomerase and use telomere homologous recombination (HR) to elongate telomeres, a mechanism termed alternative lengthening of telomeres (ALT). A hallmark of ALT cells is the recruitment of telomeres to PML bodies (termed APBs). Here, we show that the SMC5/6 complex localizes to APBs in ALT cells and is required for targeting telomeres to APBs. The MMS21 SUMO ligase of the SMC5/6 complex SUMOylates multiple telomere-binding proteins, including TRF1 and TRF2. Inhibition of TRF1 or TRF2 SUMOylation prevents APB formation. Depletion of SMC5/6 subunits by RNA interference inhibits telomere HR, causing telomere shortening and senescence in ALT cells. Thus, the SMC5/6 complex facilitates telomere HR and elongation in ALT cells by promoting APB formation through SUMOylation of telomere-binding proteins.
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Affiliation(s)
- Patrick Ryan Potts
- Department of Pharmacology, The University of Texas Southwestern Medical Center, 6001 Forest Park Road, Dallas, Texas 75390-9041, USA
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Kosoy A, Calonge TM, Outwin EA, O'Connell MJ. Fission yeast Rnf4 homologs are required for DNA repair. J Biol Chem 2007; 282:20388-94. [PMID: 17502373 DOI: 10.1074/jbc.m702652200] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
We describe two RING finger proteins in the fission yeast Schizosaccharomyces pombe, Rfp1 and Rfp2. We show that these proteins function redundantly in DNA repair. Rfp1 was isolated as a Chk1-interacting protein in a two-hybrid screen and has high amino acid sequence similarity to Rfp2. Deletion of either gene does not cause a phenotype, but a double deletion (rfp1Deltarfp2Delta) showed poor viability and defects in cell cycle progression. These cells are also sensitive to DNA-damaging agents, although they maintained normal checkpoint signaling to Chk1. Rfp1 and Rfp2 are most closely related to human Rnf4, and we showed that Rnf4 can substitute functionally for Rfp1 and/or Rfp2. The double mutants also showed significantly increased levels of protein SUMOylation, and we identified an S. pombe Ulp2/Smt4 homolog that, when overexpressed, reduced SUMO levels and suppressed the DNA damage sensitivity of rfp1Delta rfp2Delta cells.
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Affiliation(s)
- Ana Kosoy
- Department of Oncological Sciences, Mount Sinai School of Medicine, One Gustave L. Levy Place, New York, NY 10029, USA
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Díaz-Martínez LA, Giménez-Abián JF, Azuma Y, Guacci V, Giménez-Martín G, Lanier LM, Clarke DJ. PIASgamma is required for faithful chromosome segregation in human cells. PLoS One 2006; 1:e53. [PMID: 17183683 PMCID: PMC1762334 DOI: 10.1371/journal.pone.0000053] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2006] [Accepted: 10/24/2006] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND The precision of the metaphase-anaphase transition ensures stable genetic inheritance. The spindle checkpoint blocks anaphase onset until the last chromosome biorients at metaphase plate, then the bonds between sister chromatids are removed and disjoined chromatids segregate to the spindle poles. But, how sister separation is triggered is not fully understood. PRINCIPAL FINDINGS We identify PIASgamma as a human E3 sumo ligase required for timely and efficient sister chromatid separation. In cells lacking PIASgamma, normal metaphase plates form, but the spindle checkpoint is activated, leading to a prolonged metaphase block. Sister chromatids remain cohered even if cohesin is removed by depletion of hSgo1, because DNA catenations persist at centromeres. PIASgamma-depleted cells cannot properly localize Topoisomerase II at centromeres or in the cores of mitotic chromosomes, providing a functional link between PIASgamma and Topoisomerase II. CONCLUSIONS PIASgamma directs Topoisomerase II to specific chromosome regions that require efficient removal of DNA catenations prior to anaphase. The lack of this activity activates the spindle checkpoint, protecting cells from non-disjunction. Because DNA catenations persist without PIASgamma in the absence of cohesin, removal of catenations and cohesin rings must be regulated in parallel.
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Affiliation(s)
- Laura A. Díaz-Martínez
- Department of Genetics, Cell Biology and Development, University of Minnesota Medical SchoolMinneapolis, Minnesota, United States of America
| | - Juan F. Giménez-Abián
- Department of Genetics, Cell Biology and Development, University of Minnesota Medical SchoolMinneapolis, Minnesota, United States of America
- Proliferación Celular, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones CientíficasMadrid, Spain
| | - Yoshiaki Azuma
- Department of Molecular Biosciences, University of KansasLawrence, Kansas, United States of America
| | - Vincent Guacci
- Carnegie Institute, Department of EmbryologyBaltimore, Maryland, United States of America
| | - Gonzalo Giménez-Martín
- Proliferación Celular, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones CientíficasMadrid, Spain
| | - Lorene M. Lanier
- Department of Neuroscience, University of MinnesotaMinneapolis, Minnesota, United States of America
| | - Duncan J. Clarke
- Department of Genetics, Cell Biology and Development, University of Minnesota Medical SchoolMinneapolis, Minnesota, United States of America
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de Carvalho CE, Colaiácovo MP. SUMO-mediated regulation of synaptonemal complex formation during meiosis. Genes Dev 2006; 20:1986-92. [PMID: 16882975 DOI: 10.1101/gad.1457806] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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