101
|
Modifications of p53: competing for the lysines. Curr Opin Genet Dev 2009; 19:18-24. [PMID: 19179064 DOI: 10.1016/j.gde.2008.11.010] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2008] [Accepted: 11/26/2008] [Indexed: 11/20/2022]
Abstract
The p53 tumour suppressor protein is subject to numerous post-translational modifications, which coalesce in various combinations and patterns to regulate its activity. In addition to a multitude of phosphorylated serines and threonines, many of the lysine residues in p53 can be modified to regulate activity, stability and subcellular localization of the protein. This complexity is amplified by the variety of modifications that can target the same lysine residue - often with opposing effects on p53 function.
Collapse
|
102
|
Golebiowski F, Matic I, Tatham MH, Cole C, Yin Y, Nakamura A, Cox J, Barton GJ, Mann M, Hay RT. System-wide changes to SUMO modifications in response to heat shock. Sci Signal 2009; 2:ra24. [PMID: 19471022 DOI: 10.1126/scisignal.2000282] [Citation(s) in RCA: 383] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Covalent conjugation of the small ubiquitin-like modifier (SUMO) proteins to target proteins regulates many important eukaryotic cellular mechanisms. Although the molecular consequences of the conjugation of SUMO proteins are relatively well understood, little is known about the cellular signals that regulate the modification of their substrates. Here, we show that SUMO-2 and SUMO-3 are required for cells to survive heat shock. Through quantitative labeling techniques, stringent purification of SUMOylated proteins, advanced mass spectrometric technology, and novel techniques of data analysis, we quantified heat shock-induced changes in the SUMOylation state of 766 putative substrates. In response to heat shock, SUMO was polymerized into polySUMO chains and redistributed among a wide range of proteins involved in cell cycle regulation; apoptosis; the trafficking, folding, and degradation of proteins; transcription; translation; and DNA replication, recombination, and repair. This comprehensive proteomic analysis of the substrates of a ubiquitin-like modifier (Ubl) identifies a pervasive role for SUMO proteins in the biologic response to hyperthermic stress.
Collapse
Affiliation(s)
- Filip Golebiowski
- 1Wellcome Trust Centre for Gene Regulation and Expression, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, UK
| | | | | | | | | | | | | | | | | | | |
Collapse
|
103
|
Grabbe C, Dikic I. Functional Roles of Ubiquitin-Like Domain (ULD) and Ubiquitin-Binding Domain (UBD) Containing Proteins. Chem Rev 2009; 109:1481-94. [DOI: 10.1021/cr800413p] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Caroline Grabbe
- Institute of Biochemistry II and Cluster of Excellence Macromolecular Complexes, Goethe University Frankfurt am Main, Theodor-Stern-Kai 7, D-60590 Frankfurt (Main), Germany, Mediterranean Institute for Life Sciences, 21000 Split, Croatia, and Department of Immunology, School of Medicine, University of Split, Soltanska 2, 21 000 Split, Croatia
| | - Ivan Dikic
- Institute of Biochemistry II and Cluster of Excellence Macromolecular Complexes, Goethe University Frankfurt am Main, Theodor-Stern-Kai 7, D-60590 Frankfurt (Main), Germany, Mediterranean Institute for Life Sciences, 21000 Split, Croatia, and Department of Immunology, School of Medicine, University of Split, Soltanska 2, 21 000 Split, Croatia
| |
Collapse
|
104
|
Abstract
Post-translational modification of the cell's proteome by ubiquitin and ubiquitin-like proteins provides dynamic functional regulation. Ubiquitin and SUMO are well-studied post-translational modifiers that typically impart distinct effects on their targets. The recent discovery that modification by SUMO can target proteins for ubiquitination and proteasomal degradation sets a new paradigm in the field, and offers insights into the roles of SUMO and ubiquitin in genome stability.
Collapse
|
105
|
Park HJ, Zheng H, Kulkarni D, Kerrigan J, Pungaliya P, Saleem A, Rubin EH. Identification of phosphorylation sites of TOPORS and a role for serine 98 in the regulation of ubiquitin but not SUMO E3 ligase activity. Biochemistry 2009; 47:13887-96. [PMID: 19053840 DOI: 10.1021/bi801904q] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
TOPORS is the first example of a protein that possesses both ubiquitin and SUMO E3 ligase activity. The ubiquitination activity maps to a conserved RING domain in the N-terminal region of the protein, which is not required for sumoylation activity. Similar to other E3 ligases, it is likely that the ubiquitin and sumoylation activities of TOPORS are regulated by post-translational modifications. Therefore, we employed mass spectrometry to identify post-translational modifications of TOPORS. Several putative phosphorylated regions were identified in conserved regions of the protein. We investigated the role of phosphorylation of serine 98, which is adjacent to the RING domain, in both cells and in vitro. Mutation of serine 98 to aspartic acid resulted in an increase in the ubiquitin ligase activity of TOPORS both in cells and in vitro. In addition, this mutation increased the binding of TOPORS to the E2 enzyme UbcH5a both in vitro and in cells. Conversely, a phospho-deficient mutant (S98A) exhibited little change in ubiquitin ligase activity compared to wild-type TOPORS, both in cells and in vitro. Neither of the mutants affected the localization of TOPORS to punctate nuclear regions. In addition, neither mutant affected the SUMO ligase activity of TOPORS in cells or in vitro. Molecular modeling studies support a role for serine 98 in regulating TOPORS-E2 interactions. Our findings indicate that phosphorylation of serine 98 regulates the ubiquitin but not the SUMO ligase activity of TOPORS, consistent with a potential binary switch function for TOPORS in protein ubiquitination versus sumoylation.
Collapse
Affiliation(s)
- Hye-Jin Park
- Departments of Pharmacology and Medicine, The Cancer Institute of New Jersey, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, 195 Little Albany Street, New Brunswick, New Jersey 08901, USA
| | | | | | | | | | | | | |
Collapse
|
106
|
Kim KI, Baek SH. Small ubiquitin-like modifiers in cellular malignancy and metastasis. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2009; 273:265-311. [PMID: 19215907 DOI: 10.1016/s1937-6448(08)01807-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Small ubiquitin-like modifiers (SUMOs) mediate a variety of cellular functions of protein targets mainly in the nucleus but in other cellular compartments as well, and thereby participate in maintaining cellular homeostasis. SUMO system plays important roles in transcriptional regulation, DNA damage responses, maintaining genome integrity, and signaling pathways. Thus, in some cases, loss of regulated control on SUMOylation/deSUMOylation processes causes a defect in maintaining homeostasis and hence gives a cue to cancer development and progression. Furthermore, recent studies have revealed that SUMO system is involved in cancer metastasis. In this review, we will summarize the possible role of SUMO system in cancer development, progression, and metastasis and discuss future directions.
Collapse
Affiliation(s)
- Keun Il Kim
- Department of Biological Sciences, Research Center for Women's Disease, Sookmyung Women's University, Seoul, Korea
| | | |
Collapse
|
107
|
Yang Y, Kitagaki J, Wang H, Hou DX, Perantoni AO. Targeting the ubiquitin-proteasome system for cancer therapy. Cancer Sci 2008; 100:24-8. [PMID: 19037995 DOI: 10.1111/j.1349-7006.2008.01013.x] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The ubiquitin-proteasome system plays a critical role in controlling the level, activity and location of various cellular proteins. Significant progress has been made in investigating the molecular mechanisms of ubiquitination, particularly in understanding the structure of the ubiquitination machinery and identifying ubiquitin protein ligases, the primary specificity-determining enzymes. Therefore, it is now possible to target specific molecules involved in ubiquitination and proteasomal degradation to regulate many cellular processes such as signal transduction, proliferation and apoptosis. In particular, alterations in ubiquitination are observed in most, if not all, cancer cells. This is manifested by destabilization of tumor suppressors, such as p53, and overexpression of oncogenes such as c-Myc and c-Jun. In addition to the development and clinical validation of proteasome inhibitor, bortezomib, in myeloma therapy, recent studies have demonstrated that it is possible to develop inhibitors for specific ubiquitination and deubiquitination enzymes. With the help of structural studies, rational design and chemical synthesis, it is conceivable that we will be able to use 'druggable' inhibitors of the ubiquitin system to evaluate their effects in animal tumor models in the not-so-distant future.
Collapse
Affiliation(s)
- Yili Yang
- Cancer and Developmental Biology Laboratory, National Cancer Institute at Frederick, National Institutes of Health, Frederick, MD 21702, USA.
| | | | | | | | | |
Collapse
|
108
|
Ubc9 sumoylation regulates SUMO target discrimination. Mol Cell 2008; 31:371-82. [PMID: 18691969 DOI: 10.1016/j.molcel.2008.05.022] [Citation(s) in RCA: 174] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2008] [Revised: 04/23/2008] [Accepted: 05/29/2008] [Indexed: 01/05/2023]
Abstract
Posttranslational modification with small ubiquitin-related modifier, SUMO, is a widespread mechanism for rapid and reversible changes in protein function. Considering the large number of known targets, the number of enzymes involved in modification seems surprisingly low: a single E1, a single E2, and a few distinct E3 ligases. Here we show that autosumoylation of the mammalian E2-conjugating enzyme Ubc9 at Lys14 regulates target discrimination. While not altering its activity toward HDAC4, E2-25K, PML, or TDG, sumoylation of Ubc9 impairs its activity on RanGAP1 and strongly activates sumoylation of the transcriptional regulator Sp100. Enhancement depends on a SUMO-interacting motif (SIM) in Sp100 that creates an additional interface with the SUMO conjugated to the E2, a mechanism distinct from Ubc9 approximately SUMO thioester recruitment. The crystal structure of sumoylated Ubc9 demonstrates how the newly created binding interface can provide a gain in affinity otherwise provided by E3 ligases.
Collapse
|
109
|
Liu B, Shuai K. Regulation of the sumoylation system in gene expression. Curr Opin Cell Biol 2008; 20:288-93. [PMID: 18468876 DOI: 10.1016/j.ceb.2008.03.014] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2008] [Accepted: 03/20/2008] [Indexed: 11/17/2022]
Abstract
Protein sumoylation has emerged as an important regulatory mechanism for the transcriptional machinery. Sumoylation is a highly dynamic process that is regulated in response to cellular stimuli or pathogenic challenges. Altered activity of the small ubiquitin-like modifier (SUMO) conjugation system is associated with human cancers and inflammation. Thus, understanding the regulation of protein sumoylation is important for the design of SUMO-based therapeutic strategies for the treatment of human diseases. Recent studies indicate that the sumoylation system can be regulated through multiple mechanisms, including the regulation of the expression of various components of the sumoylation pathway, and the modulation of the activity of SUMO enzymes. In addition, extracellular stimuli can signal the nucleus to trigger the rapid promoter recruitment of SUMO E3 ligases, resulting in the immediate repression of transcription. Finally, the sumoylation system can also be regulated through crosstalk with other post-translational modifications, including phosphorylation, ubiquitination, and acetylation.
Collapse
Affiliation(s)
- Bin Liu
- Division of Hematology-Oncology, Department of Medicine, University of California Los Angeles, Los Angeles, CA 90095, United States
| | | |
Collapse
|
110
|
Tang Z, Hecker CM, Scheschonka A, Betz H. Protein interactions in the sumoylation cascade: lessons from X-ray structures. FEBS J 2008; 275:3003-15. [PMID: 18492068 DOI: 10.1111/j.1742-4658.2008.06459.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Sumoylation is a multi-step protein modification reaction in which SUMO (small ubiquitin-like modifier) proteins are covalently attached to lysine residues of substrate proteins. Here, we compare the sequences and structures of modifiers and enzymes involved in sumoylation with those of the related ubiquitination and neddylation cascades. By using available structural data on modifier/enzyme/substrate interactions, we discuss and model sumoylation complexes that include SUMO-1 and the E1 and E2 enzymes Aos1-uba2 and ubc9, or SUMO-1 and E2 together with the E3 ligase RanBP2 and its substrate RanGAP1. Their comparison provides insight into the protein interactions underlying sumoylation, and suggests how SUMO proteins may be translocated between enzymes during the various steps of the protein modification reaction.
Collapse
Affiliation(s)
- Zhongshu Tang
- Department of Neurochemistry, Max-Planck-Institute for Brain Research, Deutschordenstrasse 46, Frankfurt, Germany
| | | | | | | |
Collapse
|
111
|
Tan JAT, Sun Y, Song J, Chen Y, Krontiris TG, Durrin LK. SUMO conjugation to the matrix attachment region-binding protein, special AT-rich sequence-binding protein-1 (SATB1), targets SATB1 to promyelocytic nuclear bodies where it undergoes caspase cleavage. J Biol Chem 2008; 283:18124-34. [PMID: 18408014 DOI: 10.1074/jbc.m800512200] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
SATB1 (special AT-rich sequence-binding protein-1) provides a key link between DNA loop organization, chromatin modification/remodeling, and association of transcription factors at matrix attachment regions (MARs). To investigate the role of SATB1 in cellular events, we performed a yeast two-hybrid screen that identified SUMO-1, Ubc9, and protein inhibitor of activated STAT (PIAS) family members as SATB1 interaction partners. These proteins, working in concert, enhanced SUMO conjugation to lysine-744 of SATB1. Overexpression of SUMO or PIAS in Jurkat cells, which express high levels of endogenous SATB1, exhibited enhanced caspase cleavage of this MAR-associating protein. Sumoylation-deficient SATB1 (SATB1(K744R)) failed to display the characteristic caspase cleavage pattern; however, fusion of SUMO in-frame to SATB1(K744R) restored cleavage. A SUMO-independent interaction of inactive caspase-6 and SATB1 was noted. A subset of total cellular SATB1 localized into promyelocytic leukemia nuclear bodies where enhanced SATB1 cleavage was detected subsequent to caspase activation. These results reveal a novel sumoylation-directed caspase cleavage of this key regulatory molecule. The role of regulated proteolysis of SATB1 may be to control transcription in immune cells during normal cell functions or to assist in efficient and rapid clearance of nonfunctional or potentially damaging immune cells.
Collapse
Affiliation(s)
- Joseph-Anthony T Tan
- Division of Molecular Medicine, Division of Immunology, and Graduate School of Biological Sciences, Beckman Research Institute of the City of Hope Medical Center, Duarte, CA 91010, USA
| | | | | | | | | | | |
Collapse
|
112
|
Abstract
The small ubiquitin-like modifier proteins (Smt3 in yeast and SUMOs 1-4 in vertebrates) are members of the ubiquitin super family. Like ubiquitin, the SUMOs are protein modifiers that are covalently attached to the epsilon-amino group of lysine residues in the substrates. The application of proteomics to the SUMO field has greatly expanded both the number of known targets and the number of identified target lysines. As new refinements of proteomic techniques are developed and applied to sumoylation, an explosion of novel data is likely in the next 5 years. This ability to examine sumoylated proteins globally, rather than individually, will lead to new insights into both the functions of the individual SUMO types, and how dynamic changes in overall sumoylation occur in response to alterations in cellular environment. In addition, there is a growing appreciation for the existence of cross-talk mechanisms between the sumoylation and ubiquitinylation processes. Rather than being strictly parallel, these two systems have many points of intersection, and it is likely that the coordination of these two systems is a critical contributor to the regulation of many fundamental cellular events.
Collapse
Affiliation(s)
- Van G Wilson
- Department of Microbial & Molecular Pathogenesis, College of Medicine, Texas A&M Health Science Center, College Station, TX 77843-1114, USA.
| | | |
Collapse
|
113
|
Schwamborn K, Knipscheer P, van Dijk E, van Dijk WJ, Sixma TK, Meloen RH, Langedijk JPM. SUMO assay with peptide arrays on solid support: insights into SUMO target sites. J Biochem 2008; 144:39-49. [PMID: 18344540 DOI: 10.1093/jb/mvn039] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The modification of proteins by SUMO (small ubiquitin-like modifier) regulates various cellular processes. Sumoylation often occurs on a specific lysine residue within the consensus motif psiKxE/D. However, little is known about the specificity and selectivity of SUMO target sites. We describe here a SUMO assay with peptide array on solid support for the simultaneous characterization of hundreds of different SUMO target sites. This approach was used to characterize known SUMO substrates. The position of the motif within the peptide and the amino acids flanking the acceptor site affected the efficiency of SUMO modification. Interestingly, a sequence of only four amino acids, corresponding to the SUMO consensus motif without flanking amino acids, was a bona fide target site. Analysis of a peptide library for all variants of the psiKxE/D consensus motif revealed that the first and third positions in the tetrapeptide preferably contain aromatic amino acid residues. Furthermore, by adding the SUMO E3 ligase PIAS1 to the reaction mixture, we show specific enhancement of the modification of a PIAS1-dependent SUMO substrate in this system. Overall, our results demonstrate that the sumoylation assay with peptide array on solid support can be used for the high-throughput characterization of SUMO target sites, and provide new insights into the composition, selectivity and specificity of SUMO target sites.
Collapse
Affiliation(s)
- Klaus Schwamborn
- Pepscan Therapeutics BV, Zuidersluisweg 2, 8243 RC Lelystad, the Netherlands.
| | | | | | | | | | | | | |
Collapse
|
114
|
Guan B, Pungaliya P, Li X, Uquillas C, Mutton LN, Rubin EH, Bieberich CJ. Ubiquitination by TOPORS regulates the prostate tumor suppressor NKX3.1. J Biol Chem 2007; 283:4834-40. [PMID: 18077445 DOI: 10.1074/jbc.m708630200] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The NKX3.1 gene located at 8p21.2 encodes a homeodomain-containing transcription factor that acts as a haploinsufficient tumor suppressor in prostate cancer. Diminished protein expression of NKX3.1 has been observed in prostate cancer precursors and carcinomas. TOPORS is a ubiquitously expressed E3 ubiquitin ligase that can ubiquitinate tumor suppressor p53. Here we report interaction between NKX3.1 and TOPORS. NKX3.1 can be ubiquitinated by TOPORS in vitro and in vivo, and overexpression of TOPORS leads to NKX3.1 proteasomal degradation in prostate cancer cells. Conversely, small interfering RNA-mediated knockdown of TOPORS leads to an increased steady-state level and prolonged half-life of NKX3.1. These data establish TOPORS as a negative regulator of NKX3.1 and implicate TOPORS in prostate cancer progression.
Collapse
Affiliation(s)
- Bin Guan
- Department of Biological Sciences, University of Maryland, Baltimore County, Baltimore, Maryland 21250, USA
| | | | | | | | | | | | | |
Collapse
|
115
|
Martin S, Wilkinson KA, Nishimune A, Henley JM. Emerging extranuclear roles of protein SUMOylation in neuronal function and dysfunction. Nat Rev Neurosci 2007; 8:948-59. [PMID: 17987030 PMCID: PMC3314512 DOI: 10.1038/nrn2276] [Citation(s) in RCA: 161] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Post-translational protein modifications are integral components of signalling cascades that enable cells to efficiently, rapidly and reversibly respond to extracellular stimuli. These modifications have crucial roles in the CNS, where the communication between neurons is particularly complex. SUMOylation is a post-translational modification in which a member of the small ubiquitin-like modifier (SUMO) family of proteins is conjugated to lysine residues in target proteins. It is well established that SUMOylation controls many aspects of nuclear function, but it is now clear that it is also a key determinant in many extranuclear neuronal processes, and it has also been implicated in a wide range of neuropathological conditions.
Collapse
Affiliation(s)
- Stéphane Martin
- MRC Centre for Synaptic Plasticity, Department of Anatomy, School of Medical Sciences, University of Bristol, University Walk, Bristol, BS8 1TD, UK
| | | | | | | |
Collapse
|
116
|
Hammer E, Heilbronn R, Weger S. The E3 ligase Topors induces the accumulation of polysumoylated forms of DNA topoisomerase I in vitro and in vivo. FEBS Lett 2007; 581:5418-24. [PMID: 17976381 DOI: 10.1016/j.febslet.2007.10.040] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2007] [Revised: 10/22/2007] [Accepted: 10/22/2007] [Indexed: 11/30/2022]
Abstract
Human Topors has originally been identified as binding partner of p53 and DNA topoisomerase I (TOP1). It can function as both an ubiquitin and SUMO-1 E3 ligase for p53. Here we demonstrate that Topors enhances the formation of high-molecular weight SUMO-1 conjugates of TOP1 in a reconstituted in vitro system and also in human osteosarcoma cells, similar to treatment with CPT. In contrast to the situation observed with p53, overall sumoylation levels were rather unaffected. Experiments with TOP1 point mutants strongly suggest that the high-molecular weight conjugates represent SUMO-1 chains formed on a limited number of SUMO-1 acceptor sites.
Collapse
Affiliation(s)
- Eva Hammer
- Institute of Virology, Charité Campus Benjamin Franklin, Free University of Berlin, Hindenburgdamm 27, 12203 Berlin, Germany
| | | | | |
Collapse
|
117
|
Pungaliya P, Kulkarni D, Park HJ, Marshall H, Zheng H, Lackland H, Saleem A, Rubin EH. TOPORS functions as a SUMO-1 E3 ligase for chromatin-modifying proteins. J Proteome Res 2007; 6:3918-23. [PMID: 17803295 DOI: 10.1021/pr0703674] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
TOPORS is the first example of a protein with both ubiquitin and SUMO-1 E3 ligase activity and has been implicated as a tumor suppressor in several different malignancies. To gain insight into the cellular role of TOPORS, a proteomic screen was performed to identify candidate sumoylation substrates. The results indicate that many of the putative substrates are involved in chromatin modification or transcriptional regulation. Transfection studies confirmed mammalian Sin3A as a sumoylation substrate for TOPORS. These findings suggest that TOPORS may function as a tumor suppressor by regulating mSin3A and other proteins involved in chromatin modification.
Collapse
Affiliation(s)
- Pooja Pungaliya
- Department of Pharmacology, The Cancer Institute of New Jersey, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, 195 Little Albany Street, New Brunswick, New Jersey 08901, USA
| | | | | | | | | | | | | | | |
Collapse
|
118
|
Ii T, Mullen JR, Slagle CE, Brill SJ. Stimulation of in vitro sumoylation by Slx5-Slx8: evidence for a functional interaction with the SUMO pathway. DNA Repair (Amst) 2007; 6:1679-91. [PMID: 17669696 PMCID: PMC2100399 DOI: 10.1016/j.dnarep.2007.06.004] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2007] [Revised: 06/13/2007] [Accepted: 06/14/2007] [Indexed: 11/15/2022]
Abstract
The yeast genes SLX5 and SLX8 were identified based on their requirement for viability in the absence of the Sgs1 DNA helicase. Loss of these genes results in genome instability, nibbled colonies, and other phenotypes associated with defects in sumoylation. The Slx5 and Slx8 proteins form a stable complex and each subunit contains a single RING-finger domain at its C-terminus. To determine the physiological function of the Slx5-8 complex, we explored its interaction with the SUMO pathway. Curing 2micro circle from the mutants, suppressed their nibbled colony phenotype and partially improved their growth rate, but did not affect their sensitivity to hydroxyurea. The increase in sumoylation observed in slx5Delta and slx8Delta mutants was found to be dependent on the Siz1 SUMO ligase. Physical interactions between the Slx5-8 complex and both Ubc9 and Smt3 were identified and characterized. Using in vitro reactions, we show that Slx5, Slx8, or the Slx5-8 complex stimulates the formation of SUMO chains and the sumoylation of a test substrate. Interestingly, a functional RING-finger domain is not required for this stimulation in vitro. These biochemical data demonstrate for the first time that the Slx5 and Slx8 complex is capable of interacting directly with the SUMO pathway.
Collapse
Affiliation(s)
| | | | | | - Steven J. Brill
- *To whom correspondence should be addressed, Phone (732) 235-4197, Fax (732) 235-4880,
| |
Collapse
|
119
|
Dorval V, Fraser PE. SUMO on the road to neurodegeneration. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2007; 1773:694-706. [PMID: 17475350 DOI: 10.1016/j.bbamcr.2007.03.017] [Citation(s) in RCA: 138] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2007] [Revised: 03/22/2007] [Accepted: 03/23/2007] [Indexed: 11/24/2022]
Abstract
Sumoylation is a post-translational modification by which small ubiquitin-like modifiers (SUMO) are covalently conjugated to target proteins. This reversible pathway provides a rapid and efficient way to modulate the subcellular localization, activity and stability of a wide variety of substrates. Similar to its well-known cousin ubiquitin, SUMO co-localize with the neuronal inclusions associated with several neurodegenerative diseases, including multiple system atrophy, Huntington's disease and other related polyglutamine disorders. The identification of huntingtin, ataxin-1, tau and alpha-synuclein as SUMO substrates further supports the involvement of sumoylation in the pathogenesis of this family of neurological diseases. In addition to direct targeting of these constituent proteins, sumoylation also impacts other disease pathways such as oxidative stress, protein aggregation and proteasome-mediated degradation. This review highlights the recent advances in understanding the contributions of SUMO to neurodegeneration and the underlying pathogenic mechanisms of these diseases.
Collapse
Affiliation(s)
- Véronique Dorval
- Department of Medical Biophysics, Centre for Research in Neurodegenerative Diseases, University of Toronto, 6 Queen's Park Crescent West, Toronto, Ontario, Canada M5S 3H2.
| | | |
Collapse
|
120
|
Abstract
Ubiquitin and ubiquitin-like proteins (Ubls) are signalling messengers that control many cellular functions, such as cell proliferation, apoptosis, the cell cycle and DNA repair. It is becoming apparent that the deregulation of ubiquitin pathways results in the development of human diseases, including many types of tumours. Here we summarize the common principles and specific features of ubiquitin and Ubls in the regulation of cancer-relevant pathways, and discuss new strategies to target ubiquitin signalling in drug discovery.
Collapse
Affiliation(s)
- Daniela Hoeller
- Institute of Biochemistry II, Goethe University School of Medicine, University Hospital, Building 75, Theodour-Stern-Kai 7, D-60590 Frankfurt, Germany
| | | | | |
Collapse
|
121
|
Moschos SJ, Mo YY. Role of SUMO/Ubc9 in DNA Damage Repair and Tumorigenesis. J Mol Histol 2006; 37:309-19. [PMID: 16758298 DOI: 10.1007/s10735-006-9030-0] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2006] [Accepted: 04/17/2006] [Indexed: 11/25/2022]
Abstract
DNA damage repair is an important cell function for genome integrity and its deregulation can lead to genomic instability and development of malignancies. Sumoylation is an increasingly important ubiquitin-like modification of proteins affecting protein stability, enzymatic activity, nucleocytoplasmic trafficking, and protein-protein interactions. In particular, several important DNA repair enzymes are subject to sumoylation, which appears to play a role in copping with DNA damage insults. Recent reports indicate that Ubc9, the single SUMO E2 enzyme catalyzing the conjugation of SUMO to target proteins, is overexpressed in certain tumors, such as lung adenocarcinoma, ovarian carcinoma and melanoma, suggestive of its clinic significance. This review summarizes the most important DNA damage repair pathways which are potentially affected by Ubc9/SUMO and their role in regulating the function of several proteins involved in the DNA damage repair machinery.
Collapse
Affiliation(s)
- Stergios J Moschos
- Department of Medicine, Division of Hematology-Oncology, Hillman Cancer Research Pavilion, University of Pittsburgh Medical Center, 5117 Centre Avenue, Suite 1.32e, Pittsburgh, PA 15213, USA
| | | |
Collapse
|
122
|
Capelson M, Corces VG. SUMO conjugation attenuates the activity of the gypsy chromatin insulator. EMBO J 2006; 25:1906-14. [PMID: 16628226 PMCID: PMC1456934 DOI: 10.1038/sj.emboj.7601068] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2005] [Accepted: 03/08/2006] [Indexed: 02/08/2023] Open
Abstract
Chromatin insulators have been implicated in the establishment of independent gene expression domains and in the nuclear organization of chromatin. Post-translational modification of proteins by Small Ubiquitin-like Modifier (SUMO) has been reported to regulate their activity and subnuclear localization. We present evidence suggesting that two protein components of the gypsy chromatin insulator of Dorsophila melanogaster, Mod(mdg4)2.2 and CP190, are sumoylated, and that SUMO is associated with a subset of genomic insulator sites. Disruption of the SUMO conjugation pathway improves the enhancer-blocking function of a partially active insulator, indicating that SUMO modification acts to regulate negatively the activity of the gypsy insulator. Sumoylation does not affect the ability of CP190 and Mod(mdg4)2.2 to bind chromatin, but instead appears to regulate the nuclear organization of gypsy insulator complexes. The results suggest that long-range interactions of insulator proteins are inhibited by sumoylation and that the establishment of chromatin domains can be regulated by SUMO conjugation.
Collapse
Affiliation(s)
- Maya Capelson
- Department of Biology, Johns Hopkins University, Baltimore, MD, USA
| | - Victor G Corces
- Department of Biology, Johns Hopkins University, Baltimore, MD, USA
| |
Collapse
|
123
|
Abstract
Although early studies have suggested that the oncoprotein Mdm2 is the primary E3 ubiquitin ligase for the p53 tumor suppressor, an increasing amount of data suggests that p53 ubiquitination and degradation are more complex than once thought. The discoveries of MdmX, HAUSP, ARF, COP1, Pirh2, and ARF-BP1 continue to uncover the multiple facets of this pathway. There is no question that Mdm2 plays a pivotal role in downregulating p53 activities in numerous cellular settings. Nevertheless, growing evidence challenges the conventional view that Mdm2 is essential for p53 turnover.
Collapse
Affiliation(s)
- Christopher L. Brooks
- Institute for Cancer Genetics and Department of Pathology, College of Physicians and Surgeons, Columbia University, 1150 St. Nicholas Avenue, New York, New York 10032
| | - Wei Gu
- Institute for Cancer Genetics and Department of Pathology, College of Physicians and Surgeons, Columbia University, 1150 St. Nicholas Avenue, New York, New York 10032
- Correspondence:
| |
Collapse
|
124
|
Klenk C, Humrich J, Quitterer U, Lohse MJ. SUMO-1 controls the protein stability and the biological function of phosducin. J Biol Chem 2006; 281:8357-64. [PMID: 16421094 DOI: 10.1074/jbc.m513703200] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Phosducin regulates Gbetagamma-stimulated signaling by binding to Gbetagamma subunits of heterotrimeric G-proteins. Control of phosducin activity by phosphorylation is well established. However, little is known about other mechanisms that may control phosducin activity. Here we report that phosducin is regulated at the posttranslational level by modification with the small ubiquitin-related modifier, SUMO. We demonstrate modification with SUMO for phosducin in vitro expressed in cells and for native phosducin purified from retina and the heart. A consensus motif for SUMOylation was identified in phosducin at amino acid positions 32-35. Mutation of the conserved lysine 33 to arginine in this motif abolished SUMOylation of phosducin, indicating that SUMO is attached to lysine 33 of phosducin. In transfected cells the steady-state levels of the K33R mutant protein were much lower compared with wild-type phosducin. The investigation of the stability of wild-type phosducin and of phosducinK33R showed a decreased protein stability of the SUMOylation-deficient mutant. The decreased protein stability correlated with increased ubiquitinylation of the SUMOylation-deficient mutant. These findings indicate that SUMOylation protects phosducin from proteasomal degradation. SUMOylation of phosducin decreased its ability to bind Gbetagamma. PhlP, a closely related member of the phosducin family, was not a target for SUMOylation, but its SUMOylation can be achieved by a single amino acid insertion in the conserved N terminus of PhlP. Together, these findings show that phosducin is a previously unrecognized target of SUMO modification and that SUMOylation controls phosducin stability in cells as well as its functional properties.
Collapse
Affiliation(s)
- Christoph Klenk
- Institute of Pharmacology, University of Würzburg, Versbacher Strasse 9, D-97078 Würzburg, Germany
| | | | | | | |
Collapse
|