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Zarei Ghobadi M, Mozhgani SH, Erfani Y. Identification of dysregulated pathways underlying HTLV-1-associated myelopathy/tropical spastic paraparesis through co-expression network analysis. J Neurovirol 2021; 27:820-830. [PMID: 33405203 DOI: 10.1007/s13365-020-00919-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 09/29/2020] [Accepted: 10/08/2020] [Indexed: 12/13/2022]
Abstract
Human T cell lymphotropic virus-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a pathogen-caused disease which is associated with the progressive neurological disorder. HAM/TSP affects the expression level of several proteins and dysregulates some biological pathways. To identify the interaction patterns among expressed genes in HAM/TSP patients, weighted gene co-expression network analysis (WGCNA) was applied. Three microarray datasets regarding HAM/TSP were merged, and the co-expression network was constructed among genes. A total of 38 modules were identified. Three preserved modules in HAM/TSP in comparison to the healthy subjects which also had the most connected proteins and enriched in the biological pathways were selected. These modules were enriched in pathways related to immune systems, cell cycle, viral infection, and neuronal systems. Moreover, the involvement of novel immunological-related proteins including C1QB, GBP5, PSME1, SERPING1, and UBE2C; neurological-related proteins including TUBA4A, TUBB8, and TP63; and also proteins including TRPC6, PRKG2, OPRD1, PRKACA, and TUBB4A involved in the cGMP-PKG signaling pathway, thyroid hormone synthesis, and recruitment of mitotic centrosome proteins and complexes were found. Therefore, tracing these proteins and the identified modules can shed light on the pathogenesis mechanism of HAM/TSP and help to find potential therapeutic targets. However, further experimental validation should be performed to confirm the proposed functional players.
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Affiliation(s)
- Mohadeseh Zarei Ghobadi
- Department of Virology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
- Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran
| | - Sayed-Hamidreza Mozhgani
- Department of Microbiology, School of Medicine, Alborz University of Medical Sciences, Karaj, Iran
- Non-Communicable Diseases Research Center, Alborz University of Medical Sciences, Karaj, Iran
| | - Yousef Erfani
- Department of Medical Laboratory Sciences, School of Allied Medical Sciences, Tehran University of Medical Sciences, Tehran, Iran.
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2
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Braun AL, Meghini F, Villa-Fombuena G, Guermont M, Fernandez-Martinez E, Qian Z, Dolores Martín-Bermudo M, González-Reyes A, Glover DM, Kimata Y. The careful control of Polo kinase by APC/C-Ube2C ensures the intercellular transport of germline centrosomes during Drosophila oogenesis. Open Biol 2021; 11:200371. [PMID: 34186008 PMCID: PMC8241486 DOI: 10.1098/rsob.200371] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
A feature of metazoan reproduction is the elimination of maternal centrosomes from the oocyte. In animals that form syncytial cysts during oogenesis, including Drosophila and human, all centrosomes within the cyst migrate to the oocyte where they are subsequently degenerated. The importance and the underlying mechanism of this event remain unclear. Here, we show that, during early Drosophila oogenesis, control of the Anaphase Promoting Complex/Cyclosome (APC/C), the ubiquitin ligase complex essential for cell cycle control, ensures proper transport of centrosomes into the oocyte through the regulation of Polo/Plk1 kinase, a critical regulator of the integrity and activity of the centrosome. We show that novel mutations in the APC/C-specific E2, Vihar/Ube2c, that affect its inhibitory regulation on APC/C cause precocious Polo degradation and impedes centrosome transport, through destabilization of centrosomes. The failure of centrosome migration correlates with weakened microtubule polarization in the cyst and allows ectopic microtubule nucleation in nurse cells, leading to the loss of oocyte identity. These results suggest a role for centrosome migration in oocyte fate maintenance through the concentration and confinement of microtubule nucleation activity into the oocyte. Considering the conserved roles of APC/C and Polo throughout the animal kingdom, our findings may be translated into other animals.
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Affiliation(s)
- Alexis Leah Braun
- Department of Genetics, University of Cambridge, Cambridge CB2 3EH, UK
| | - Francesco Meghini
- Department of Genetics, University of Cambridge, Cambridge CB2 3EH, UK
| | - Gema Villa-Fombuena
- Centro Andaluz de Biología del Desarrollo, CSIC/Universidad Pablo de Olavide/JA, Carretera de Utrera km 1, 41013 Sevilla, Spain
| | - Morgane Guermont
- Department of Genetics, University of Cambridge, Cambridge CB2 3EH, UK
| | | | - Zhang Qian
- School of Life Science and Technology, ShanghaiTech University, 393 Middle Huaxia Road, Shanghai 201210, People's Republic of China
| | - Maria Dolores Martín-Bermudo
- Centro Andaluz de Biología del Desarrollo, CSIC/Universidad Pablo de Olavide/JA, Carretera de Utrera km 1, 41013 Sevilla, Spain
| | - Acaimo González-Reyes
- Centro Andaluz de Biología del Desarrollo, CSIC/Universidad Pablo de Olavide/JA, Carretera de Utrera km 1, 41013 Sevilla, Spain
| | | | - Yuu Kimata
- Department of Genetics, University of Cambridge, Cambridge CB2 3EH, UK.,School of Life Science and Technology, ShanghaiTech University, 393 Middle Huaxia Road, Shanghai 201210, People's Republic of China
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3
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Presta I, Novellino F, Donato A, La Torre D, Palleria C, Russo E, Malara N, Donato G. UbcH10 a Major Actor in Cancerogenesis and a Potential Tool for Diagnosis and Therapy. Int J Mol Sci 2020; 21:E2041. [PMID: 32192022 PMCID: PMC7139792 DOI: 10.3390/ijms21062041] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 03/13/2020] [Accepted: 03/15/2020] [Indexed: 01/22/2023] Open
Abstract
Malignant transformation is a multistep process in which several molecular entities become dysregulated and result in dysfunction in the regulation of cell proliferation. In past years, scientists have gradually dissected the pathways involved in the regulation of the cell cycle. The mitotic ubiquitin-conjugating enzymes UbcH10, has been extensively studied since its cloning and characterization and it has been identified as a constantly overexpressed factor in many types of cancer. In this paper, we have reviewed the literature about UbcH10 in human cancer, pointing out the association between its overexpression and exacerbation of cancer phenotype. Moreover, many recalled studied demonstrated how immunohistochemistry or RT-PCR analysis can distinguish normal tissues and benign lesions from malignant neoplasms. In other experimental studies, many of the consequences of UbcH10 overexpression, such as increased proliferation, metastasizing, cancer progression and resistance to anticancer drugs are reversed through gene silencing techniques. In recent years, many authors have defined UbcH10 evaluation in cancer patients as a useful tool for diagnosis and therapy. This opinion is shared by the authors who advertise how it would be useful to start using in clinical practice the notions acquired about this important moleculein the carcinogenesis of many human malignancies.
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Affiliation(s)
- Ivan Presta
- Department of Health Sciences, University “Magna Græcia” of Catanzaro, 88100 Catanzaro, Italy; (C.P.); (E.R.); (G.D.)
| | - Fabiana Novellino
- Neuroimaging Unit, Institute of Bioimaging and Molecular Physiology, National Research Council (IBFM-CNR) Viale Europa, 88100 Catanzaro, Italy;
| | - Annalidia Donato
- Department of Medical and Surgical Sciences, University “Magna Graecia” of Catanzaro, 88100 Catanzaro, Italy; (A.D.); (D.L.T.)
| | - Domenico La Torre
- Department of Medical and Surgical Sciences, University “Magna Graecia” of Catanzaro, 88100 Catanzaro, Italy; (A.D.); (D.L.T.)
| | - Caterina Palleria
- Department of Health Sciences, University “Magna Græcia” of Catanzaro, 88100 Catanzaro, Italy; (C.P.); (E.R.); (G.D.)
| | - Emilio Russo
- Department of Health Sciences, University “Magna Græcia” of Catanzaro, 88100 Catanzaro, Italy; (C.P.); (E.R.); (G.D.)
| | - Natalia Malara
- Department of Clinical and Experimental Medicine, University “Magna Graecia” of Catanzaro, 88100 Catanzaro, Italy;
| | - Giuseppe Donato
- Department of Health Sciences, University “Magna Græcia” of Catanzaro, 88100 Catanzaro, Italy; (C.P.); (E.R.); (G.D.)
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4
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Liu B, Lee G, Wu J, Deming J, Kuei C, Harrington A, Wang L, Towne J, Lovenberg T, Liu C, Sun S. The PAR2 signal peptide prevents premature receptor cleavage and activation. PLoS One 2020; 15:e0222685. [PMID: 32078628 PMCID: PMC7032737 DOI: 10.1371/journal.pone.0222685] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 02/03/2020] [Indexed: 11/19/2022] Open
Abstract
Unlike closely related GPCRs, protease-activated receptors (PAR1, PAR2, PAR3, and PAR4) have a predicted signal peptide at their N-terminus, which is encoded by a separate exon, suggesting that the signal peptides of PARs may serve an important and unique function, specific for PARs. In this report, we show that the PAR2 signal peptide, when fused to the N-terminus of IgG-Fc, effectively induced IgG-Fc secretion into culture medium, thus behaving like a classical signal peptide. The presence of PAR2 signal peptide has a strong effect on PAR2 cell surface expression, as deletion of the signal peptide (PAR2ΔSP) led to dramatic reduction of the cell surface expression and decreased responses to trypsin or the synthetic peptide ligand (SLIGKV). However, further deletion of the tethered ligand region (SLIGKV) at the N-terminus rescued the cell surface receptor expression and the response to the synthetic peptide ligand, suggesting that the signal peptide of PAR2 may be involved in preventing PAR2 from intracellular protease activation before reaching the cell surface. Supporting this hypothesis, an Arg36Ala mutation on PAR2ΔSP, which disabled the trypsin activation site, increased the receptor cell surface expression and the response to ligand stimulation. Similar effects were observed when PAR2ΔSP expressing cells were treated with protease inhibitors. Our findings indicated that there is a role of the PAR2 signal peptide in preventing the premature activation of PAR2 from intracellular protease cleavage before reaching the cells surface. The same mechanism may also apply to PAR1, PAR3, and PAR4.
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Affiliation(s)
- Belinda Liu
- Janssen Research & Development, LLC, San Diego, California, United States of America
| | - Grace Lee
- Janssen Research & Development, LLC, San Diego, California, United States of America
| | - Jiejun Wu
- Janssen Research & Development, LLC, San Diego, California, United States of America
| | - Janise Deming
- Janssen Research & Development, LLC, San Diego, California, United States of America
| | - Chester Kuei
- Janssen Research & Development, LLC, San Diego, California, United States of America
| | - Anthony Harrington
- Janssen Research & Development, LLC, San Diego, California, United States of America
| | - Lien Wang
- Janssen Research & Development, LLC, San Diego, California, United States of America
| | - Jennifer Towne
- Janssen Research & Development, LLC, San Diego, California, United States of America
| | - Timothy Lovenberg
- Janssen Research & Development, LLC, San Diego, California, United States of America
| | - Changlu Liu
- Janssen Research & Development, LLC, San Diego, California, United States of America
| | - Siquan Sun
- Janssen Research & Development, LLC, San Diego, California, United States of America
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5
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Liu G, Zhao J, Pan B, Ma G, Liu L. UBE2C overexpression in melanoma and its essential role in G2/M transition. J Cancer 2019; 10:2176-2184. [PMID: 31258721 PMCID: PMC6584412 DOI: 10.7150/jca.32731] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2019] [Accepted: 04/07/2019] [Indexed: 12/21/2022] Open
Abstract
Ubiquitin‑conjugating enzyme E2C (UBE2C) is a key regulator of cell cycle progression, and its aberrant expression has been implicated in various malignancies. However, its clinical and biological roles in malignant melanoma is still unclear. In this study, we found a significant high expression level of UBE2C in melanoma by an in silico analysis of The Cancer Genome Atlas (TCGA) database, which was further validated using fresh melanoma samples. The KM plotter showed that UBE2C level was statistically related to the overall survival (OS) of melanoma patients (p<0.01). RNA interference of UBE2C inhibited the growth of melanoma cells via deactivating ERK/Akt signaling pathways, and blocked the G2/M transition through downregulation of both the level and the activity of mitosis promoting factor (MPF), triggering the apoptosis of melanoma cells. Further, silencing of UBE2C significantly inhibited the xenografted tumor growth on nude mice, indicating an important role of UBE2C in melanoma growth in vivo. Together, our results show that UBE2C may serve as a novel prognostic biomarker as well as a potential therapeutic target for melanoma.
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Affiliation(s)
- Guolong Liu
- Department of Gastrointestinal Cancer Biology, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin 300060, P.R. China
| | - Jun Zhao
- Department of Bone & Soft Tissue Tumor, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin 300060, P.R. China
| | - Boyu Pan
- Department of Gastrointestinal Cancer Biology, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin 300060, P.R. China
| | - Gang Ma
- Department of Gastrointestinal Cancer Biology, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin 300060, P.R. China
| | - Liren Liu
- Department of Gastrointestinal Cancer Biology, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin 300060, P.R. China
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6
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7
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Ma R, Kang X, Zhang G, Fang F, DU Y, Lv H. High expression of UBE2C is associated with the aggressive progression and poor outcome of malignant glioma. Oncol Lett 2016; 11:2300-2304. [PMID: 26998166 DOI: 10.3892/ol.2016.4171] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Accepted: 12/18/2015] [Indexed: 11/06/2022] Open
Abstract
Ubiquitin-conjugating enzyme E2C (UBE2C) is a key regulator of cell cycle progression and is involved in the tumorigenesis of a variety of cancers. Previous studies have demonstrated that UBE2C is an important factor in the malignant progression of astrocytic tumors. However, the association between UBE2C expression and clinical prognosis of glioma patients has not been defined. In the present study, the expression of UBE2C in gliomas and non-cancerous brain tissues were detected by microarray and immunohistochemical analysis. The association between UBE2C expression and clinicopathological characteristics of the glioma patients was evaluated. The Kaplan-Meier method and multivariate Cox's proportional hazards model were used to analyze the survival time of the patients. The results demonstrated that the expression levels of UBE2C in anaplastic gliomas and glioblastoma (GBM) patients were significantly higher compared to low-grade gliomas, in microarray and immunohistochemistry analysis. A higher UBE2C expression was associated with a significantly decreased overall survival time in patients possessing anaplastic gliomas (P<0.01) and GBMs (P<0.05). Multivariate analysis of 80 GBM patients revealed that UBE2C expression was an independent prognostic factor. To the best of our knowledge, the present data suggest for the first time that UBE2C overexpression is strongly associated with an aggressive progression and poor outcome of malignant glioma. Therefore, UBE2C overexpression may be used as a predictor of poor prognosis in patients with malignant glioma.
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Affiliation(s)
- Ruimin Ma
- Laboratory Diagnosis Center, Beijing Tiantan Hospital, Capital Medical University, Beijing 100050, P.R. China; Beijing Engineering Research Center of Immunological Reagents Clinical Research, Beijing 100050, P.R. China
| | - Xixiong Kang
- Laboratory Diagnosis Center, Beijing Tiantan Hospital, Capital Medical University, Beijing 100050, P.R. China; Beijing Engineering Research Center of Immunological Reagents Clinical Research, Beijing 100050, P.R. China
| | - Guojun Zhang
- Laboratory Diagnosis Center, Beijing Tiantan Hospital, Capital Medical University, Beijing 100050, P.R. China; Beijing Engineering Research Center of Immunological Reagents Clinical Research, Beijing 100050, P.R. China
| | - Fang Fang
- Laboratory Diagnosis Center, Beijing Tiantan Hospital, Capital Medical University, Beijing 100050, P.R. China; Beijing Engineering Research Center of Immunological Reagents Clinical Research, Beijing 100050, P.R. China
| | - Yamei DU
- Laboratory Diagnosis Center, Beijing Tiantan Hospital, Capital Medical University, Beijing 100050, P.R. China; Beijing Engineering Research Center of Immunological Reagents Clinical Research, Beijing 100050, P.R. China
| | - Hong Lv
- Laboratory Diagnosis Center, Beijing Tiantan Hospital, Capital Medical University, Beijing 100050, P.R. China; Beijing Engineering Research Center of Immunological Reagents Clinical Research, Beijing 100050, P.R. China
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8
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Boban M, Ljungdahl PO, Foisner R. Atypical ubiquitylation in yeast targets lysine-less Asi2 for proteasomal degradation. J Biol Chem 2014; 290:2489-95. [PMID: 25492870 PMCID: PMC4303697 DOI: 10.1074/jbc.m114.600593] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Proteins are typically targeted for proteasomal degradation by the attachment of a polyubiquitin chain to ϵ-amino groups of lysine residues. Non-lysine ubiquitylation of proteasomal substrates has been considered an atypical and rare event limited to complex eukaryotes. Here we report that a fully functional lysine-less mutant of an inner nuclear membrane protein in yeast, Asi2, is polyubiquitylated and targeted for proteasomal degradation. Efficient degradation of lysine-free Asi2 requires E3-ligase Doa10 and E2 enzymes Ubc6 and Ubc7, components of the endoplasmic reticulum-associated degradation pathway. Together, our data suggest that non-lysine ubiquitylation may be more prevalent than currently considered.
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Affiliation(s)
- Mirta Boban
- From the Max F. Perutz Laboratories, Department of Medical Biochemistry, Medical University Vienna, A-1030 Vienna, Austria and
| | - Per O Ljungdahl
- the Department of Molecular Biosciences, Wenner-Gren Institute, Stockholm University SE-S-10691 Stockholm, Sweden
| | - Roland Foisner
- From the Max F. Perutz Laboratories, Department of Medical Biochemistry, Medical University Vienna, A-1030 Vienna, Austria and
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9
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Min M, Mayor U, Dittmar G, Lindon C. Using in vivo biotinylated ubiquitin to describe a mitotic exit ubiquitome from human cells. Mol Cell Proteomics 2014; 13:2411-25. [PMID: 24857844 PMCID: PMC4159658 DOI: 10.1074/mcp.m113.033498] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Revised: 05/19/2014] [Indexed: 11/06/2022] Open
Abstract
Mitotic division requires highly regulated morphological and biochemical changes to the cell. Upon commitment to exit mitosis, cells begin to remove mitotic regulators in a temporally and spatially controlled manner to bring about the changes that reestablish interphase. Ubiquitin-dependent pathways target these regulators to generate polyubiquitin-tagged substrates for degradation by the 26S proteasome. However, the lack of cell-based assays to investigate in vivo ubiquitination limits our knowledge of the identity of substrates of ubiquitin-mediated regulation in mitosis. Here we report an in vivo ubiquitin tagging system used in human cells that allows efficient purification of ubiquitin conjugates from synchronized cell populations. Coupling purification with mass spectrometry, we have identified a series of mitotic regulators targeted for polyubiquitination in mitotic exit. We show that some are new substrates of the anaphase-promoting complex/cyclosome and validate KIFC1 and RacGAP1/Cyk4 as two such targets involved respectively in timely mitotic spindle disassembly and cell spreading. We conclude that in vivo biotin tagging of ubiquitin can provide valuable information about the role of ubiquitin-mediated regulation in processes required for rebuilding interphase cells.
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Affiliation(s)
- Mingwei Min
- From the ‡Department of Genetics, University of Cambridge, Downing St., Cambridge CB2 3EH, UK
| | - Ugo Mayor
- §CIC Biogune, Bizkaia Teknology Park, 48160 Derio, Basque Country, Spain; ¶Ikerbasque, Basque Foundation for Science, 48011, Bilbao, Spain
| | - Gunnar Dittmar
- ‖Max Delbrück Center for Molecular Medicine, 13125 Berlin, Germany
| | - Catherine Lindon
- From the ‡Department of Genetics, University of Cambridge, Downing St., Cambridge CB2 3EH, UK;
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10
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Abstract
Viruses commonly manipulate cell cycle progression to create cellular conditions that are most beneficial to their replication. To accomplish this feat, viruses often target critical cell cycle regulators in order to have maximal effect with minimal input. One such master regulator is the large, multisubunit E3 ubiquitin ligase anaphase-promoting complex (APC) that targets effector proteins for ubiquitination and proteasome degradation. The APC is essential for cells to progress through anaphase, exit from mitosis, and prevent a premature entry into S phase. These far-reaching effects of the APC on the cell cycle are through its ability to target a number of substrates, including securin, cyclin A, cyclin B, thymidine kinase, geminin, and many others. Recent studies have identified several proteins from a number of viruses that can modulate APC activity by different mechanisms, highlighting the potential of the APC in driving viral replication or pathogenesis. Most notably, human cytomegalovirus (HCMV) protein pUL21a was recently identified to disable the APC via a novel mechanism by targeting APC subunits for degradation, both during virus infection and in isolation. Importantly, HCMV lacking both viral APC regulators is significantly attenuated, demonstrating the impact of the APC on a virus infection. Work in this field will likely lead to novel insights into viral replication and pathogenesis and APC function and identify novel antiviral and anticancer targets. Here we review viral mechanisms to regulate the APC, speculate on their roles during infection, and identify questions to be addressed in future studies.
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11
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Sarkari F, Wheaton K, La Delfa A, Mohamed M, Shaikh F, Khatun R, Arrowsmith CH, Frappier L, Saridakis V, Sheng Y. Ubiquitin-specific protease 7 is a regulator of ubiquitin-conjugating enzyme UbE2E1. J Biol Chem 2013; 288:16975-16985. [PMID: 23603909 DOI: 10.1074/jbc.m113.469262] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Ubiquitin-specific protease 7 (USP7) is a deubiquitinating enzyme found in all eukaryotes that catalyzes the removal of ubiquitin from specific target proteins. Here, we report that UbE2E1, an E2 ubiquitin conjugation enzyme with a unique N-terminal extension, is a novel USP7-interacting protein. USP7 forms a complex with UbE2E1 in vitro and in vivo through the ASTS USP7 binding motif within its N-terminal extension in an identical manner with other known USP7 binding proteins. We show that USP7 attenuates UbE2E1-mediated ubiquitination, an effect that requires the N-terminal ASTS sequence of UbE2E1 as well as the catalytic activity of USP7. Additionally, USP7 is critical in maintaining the steady state levels of UbE2E1 in cells. This study reveals a new cellular mechanism that couples the opposing activities of the ubiquitination machinery and a deubiquitinating enzyme to maintain and modulate the dynamic balance of the ubiquitin-proteasome system.
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Affiliation(s)
- Feroz Sarkari
- Department of Biology, York University, Toronto, Ontario M3J 1P3
| | - Keith Wheaton
- Department of Biology, York University, Toronto, Ontario M3J 1P3
| | - Anthony La Delfa
- Department of Biology, York University, Toronto, Ontario M3J 1P3
| | - Majda Mohamed
- Department of Biology, York University, Toronto, Ontario M3J 1P3
| | - Faryal Shaikh
- Department of Biology, York University, Toronto, Ontario M3J 1P3
| | - Rahima Khatun
- Department of Biology, York University, Toronto, Ontario M3J 1P3
| | - Cheryl H Arrowsmith
- Division of Cancer Genomics and Proteomics, Ontario Cancer Institute, University Health Network, Toronto, Ontario M5G 1L7
| | - Lori Frappier
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Vivian Saridakis
- Department of Biology, York University, Toronto, Ontario M3J 1P3.
| | - Yi Sheng
- Department of Biology, York University, Toronto, Ontario M3J 1P3.
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12
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Ambrosone A, Di Giacomo M, Leone A, Grillo MS, Costa A. Identification of early induced genes upon water deficit in potato cell cultures by cDNA-AFLP. JOURNAL OF PLANT RESEARCH 2013; 126:169-178. [PMID: 22772750 DOI: 10.1007/s10265-012-0505-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Accepted: 06/06/2012] [Indexed: 06/01/2023]
Abstract
For plant cells in the early phases of water stress exposure, the genes induced under such conditions play a key role in detecting and responding to water deficit. In this study, potato cell suspensions were used as a simplified model system to dissect early molecular changes upon low water potential. In particular, the cDNA-amplified fragment length polymorphism approach was used to capture genes rapidly activated in potato cell cultures in response to water deficit induced by short-term exposure (up to 1 h) to polyethylene glycol. Selective amplifications with 38 primer combinations allowed the visualization of about 167 transcript-derived fragments (TDFs) differentially expressed upon exposure to low water potential. The gene expression pattern of 18 up-regulated genes was further investigated by semi-quantitative reverse transcriptase polymerase chain reaction analysis. Sequencing and similarity analysis revealed that TDFs present homologies chiefly with proteins involved in chaperone activity and protein degradation (hsps, proteinase precursor), in protein synthesis (elongation factor, ribosomal proteins) and in the ROS scavenging pathway (phenylalanine ammonia-lyase, peroxidase). Our findings might contribute to describe the potential role of genes activated in the early phases of plant response to drought.
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Affiliation(s)
- Alfredo Ambrosone
- National Research Council of Italy, Institute of Plant Genetics (CNR-IGV), Via Università 133, Portici, Naples, Italy
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13
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Batra R, Harder N, Gogolin S, Diessl N, Soons Z, Jäger-Schmidt C, Lawerenz C, Eils R, Rohr K, Westermann F, König R. Time-lapse imaging of neuroblastoma cells to determine cell fate upon gene knockdown. PLoS One 2012; 7:e50988. [PMID: 23251412 PMCID: PMC3521006 DOI: 10.1371/journal.pone.0050988] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Accepted: 10/29/2012] [Indexed: 11/22/2022] Open
Abstract
Neuroblastoma is the most common extra-cranial solid tumor of early childhood. Standard therapies are not effective in case of poor prognosis and chemotherapy resistance. To improve drug therapy, it is imperative to discover new targets that play a substantial role in tumorigenesis of neuroblastoma. The mitotic machinery is an attractive target for therapeutic interventions and inhibitors can be developed to target mitotic entry, spindle apparatus, spindle activation checkpoint, and mitotic exit. We present an elaborate analysis pipeline to determine cancer specific therapeutic targets by first performing a focused gene expression analysis to select genes followed by a gene knockdown screening assay of live cells. We interrogated gene expression studies of neuroblastoma tumors and selected 240 genes relevant for tumorigenesis and cell cycle. With these genes we performed time-lapse screening of gene knockdowns in neuroblastoma cells. We classified cellular phenotypes and used the temporal context of the perturbation effect to determine the sequence of events, particularly the mitotic entry preceding cell death. Based upon this phenotype kinetics from the gene knockdown screening, we inferred dynamic gene functions in mitosis and cell proliferation. We identified six genes (DLGAP5, DSCC1, SMO, SNRPD1, SSBP1, and UBE2C) with a vital role in mitosis and these are promising therapeutic targets for neuroblastoma. Images and movies of every time point of all screened genes are available at https://ichip.bioquant.uni-heidelberg.de.
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Affiliation(s)
- Richa Batra
- Department of Bioinformatics and Functional Genomics, Institute of Pharmacy and Molecular Biotechnology, Bioquant, University of Heidelberg, Heidelberg, Germany
- Division of Theoretical Bioinformatics, German Cancer Research Centre (DKFZ), Heidelberg, Germany
| | - Nathalie Harder
- Department of Bioinformatics and Functional Genomics, Institute of Pharmacy and Molecular Biotechnology, Bioquant, University of Heidelberg, Heidelberg, Germany
- Division of Theoretical Bioinformatics, German Cancer Research Centre (DKFZ), Heidelberg, Germany
| | - Sina Gogolin
- Division of Tumor Genetics, German Cancer Research Centre (DKFZ), Heidelberg, Germany
| | - Nicolle Diessl
- Department of Genomics and Proteomics Core Facility, High-Throughput Screening, German Cancer Research Center, Heidelberg, Germany
| | - Zita Soons
- Department of Bioinformatics and Functional Genomics, Institute of Pharmacy and Molecular Biotechnology, Bioquant, University of Heidelberg, Heidelberg, Germany
- Division of Theoretical Bioinformatics, German Cancer Research Centre (DKFZ), Heidelberg, Germany
| | - Christina Jäger-Schmidt
- Division of Theoretical Bioinformatics, German Cancer Research Centre (DKFZ), Heidelberg, Germany
| | - Christian Lawerenz
- Division of Theoretical Bioinformatics, German Cancer Research Centre (DKFZ), Heidelberg, Germany
| | - Roland Eils
- Department of Bioinformatics and Functional Genomics, Institute of Pharmacy and Molecular Biotechnology, Bioquant, University of Heidelberg, Heidelberg, Germany
- Division of Theoretical Bioinformatics, German Cancer Research Centre (DKFZ), Heidelberg, Germany
| | - Karl Rohr
- Department of Bioinformatics and Functional Genomics, Institute of Pharmacy and Molecular Biotechnology, Bioquant, University of Heidelberg, Heidelberg, Germany
- Division of Theoretical Bioinformatics, German Cancer Research Centre (DKFZ), Heidelberg, Germany
| | - Frank Westermann
- Division of Tumor Genetics, German Cancer Research Centre (DKFZ), Heidelberg, Germany
| | - Rainer König
- Department of Bioinformatics and Functional Genomics, Institute of Pharmacy and Molecular Biotechnology, Bioquant, University of Heidelberg, Heidelberg, Germany
- Division of Theoretical Bioinformatics, German Cancer Research Centre (DKFZ), Heidelberg, Germany
- * E-mail:
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14
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Du H, Jie L, Xu W, Wu Y, Liu T, Li M. A monoclonal antibody against a potential cancer biomarker, human ubiquitin-conjugating enzyme E2. Hybridoma (Larchmt) 2012; 31:196-202. [PMID: 22741584 DOI: 10.1089/hyb.2012.0005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Human ubiquitin-conjugating enzyme E2, also known as UbcH10, is defined as a cyclin-selective ubiquitin carrier protein and is essential for selective degradation of many short-lived proteins in eukaryotic cells. Recently more and more data show that UbcH10 could be a potential cancer biomarker. In this study, we have developed a monoclonal antibody (MAb) against UbcH10 using an expression recombinant protein. Hybridomas F001, F007, and F008 with high affinities belong to IgG1 subclass with κ light and are highly specific for UbcH10. Further experimentation showed that MAbs F001, F007, and F008 are suitable for the development of immunoassay core agents with sufficient sensitivity and specificity in vitro by Western-blot, immunofluorescence, and immunohistochemistry. These MAbs can be used as a tool for further investigation on functions related to the role of UbcH10 in tumorigenesis and development.
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Affiliation(s)
- Hongyan Du
- Institute of Antibody Engineering, School of Biotechnology, Southern Medical University, Guangzhou, Guangdong Province, China
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15
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Müller GA, Quaas M, Schümann M, Krause E, Padi M, Fischer M, Litovchick L, DeCaprio JA, Engeland K. The CHR promoter element controls cell cycle-dependent gene transcription and binds the DREAM and MMB complexes. Nucleic Acids Res 2011; 40:1561-78. [PMID: 22064854 PMCID: PMC3287175 DOI: 10.1093/nar/gkr793] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Cell cycle-dependent gene expression is often controlled on the transcriptional level. Genes like cyclin B, CDC2 and CDC25C are regulated by cell cycle-dependent element (CDE) and cell cycle genes homology region (CHR) promoter elements mainly through repression in G(0)/G(1). It had been suggested that E2F4 binding to CDE sites is central to transcriptional regulation. However, some promoters are only controlled by a CHR. We identify the DREAM complex binding to the CHR of mouse and human cyclin B2 promoters in G(0). Association of DREAM and cell cycle-dependent regulation is abrogated when the CHR is mutated. Although E2f4 is part of the complex, a CDE is not essential but can enhance binding of DREAM. We show that the CHR element is not only necessary for repression of gene transcription in G(0)/G(1), but also for activation in S, G(2) and M phases. In proliferating cells, the B-myb-containing MMB complex binds the CHR of both promoters independently of the CDE. Bioinformatic analyses identify many genes which contain conserved CHR elements in promoters binding the DREAM complex. With Ube2c as an example from that screen, we show that inverse CHR sites are functional promoter elements that can bind DREAM and MMB. Our findings indicate that the CHR is central to DREAM/MMB-dependent transcriptional control during the cell cycle.
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Affiliation(s)
- Gerd A Müller
- Molecular Oncology, Medical School, University of Leipzig, Semmelweisstrasse 14, 04103 Leipzig, Germany
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16
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Wickliffe KE, Williamson A, Meyer HJ, Kelly A, Rape M. K11-linked ubiquitin chains as novel regulators of cell division. Trends Cell Biol 2011; 21:656-63. [PMID: 21978762 DOI: 10.1016/j.tcb.2011.08.008] [Citation(s) in RCA: 126] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2011] [Revised: 08/24/2011] [Accepted: 08/31/2011] [Indexed: 02/07/2023]
Abstract
Modification of proteins with ubiquitin chains is an essential regulatory event in cell cycle control. Differences in the connectivity of ubiquitin chains are believed to result in distinct functional consequences for the modified proteins. Among eight possible homogenous chain types, canonical Lys48-linked ubiquitin chains have long been recognized to drive the proteasomal degradation of cell cycle regulators, and Lys48 is the only essential lysine residue of ubiquitin in yeast. It thus came as a surprise that in higher eukaryotes atypical K11-linked ubiquitin chains regulate the substrates of the anaphase-promoting complex and control progression through mitosis. We discuss recent findings that shed light on the assembly and function of K11-linked chains during cell division.
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Affiliation(s)
- Katherine E Wickliffe
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, USA
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17
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Weissman AM, Shabek N, Ciechanover A. The predator becomes the prey: regulating the ubiquitin system by ubiquitylation and degradation. Nat Rev Mol Cell Biol 2011; 12:605-20. [PMID: 21860393 PMCID: PMC3545438 DOI: 10.1038/nrm3173] [Citation(s) in RCA: 240] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Ubiquitylation (also known as ubiquitination) regulates essentially all of the intracellular processes in eukaryotes through highly specific modification of numerous cellular proteins, which is often tightly regulated in a spatial and temporal manner. Although most often associated with proteasomal degradation, ubiquitylation frequently serves non-proteolytic functions. In light of its central roles in cellular regulation, it has not been surprising to find that many of the components of the ubiquitin system itself are regulated by ubiquitylation. This observation has broad implications for pathophysiology.
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Affiliation(s)
- Allan M. Weissman
- Laboratory of Protein Dynamics and Signaling, National Cancer Institute, Frederick, Maryland 21702, USA
| | - Nitzan Shabek
- Cancer and Vascular Biology Research Center, The Rappaport Faculty of Medicine and Research Institute, Technion-Israel Institute of Technology, Haifa 31096, Israel
| | - Aaron Ciechanover
- Cancer and Vascular Biology Research Center, The Rappaport Faculty of Medicine and Research Institute, Technion-Israel Institute of Technology, Haifa 31096, Israel
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18
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Huang X, Summers MK, Pham V, Lill JR, Liu J, Lee G, Kirkpatrick DS, Jackson PK, Fang G, Dixit VM. Deubiquitinase USP37 is activated by CDK2 to antagonize APC(CDH1) and promote S phase entry. Mol Cell 2011; 42:511-23. [PMID: 21596315 DOI: 10.1016/j.molcel.2011.03.027] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2010] [Revised: 03/07/2011] [Accepted: 03/30/2011] [Indexed: 11/26/2022]
Abstract
Cell cycle progression requires the E3 ubiquitin ligase anaphase-promoting complex (APC/C), which uses the substrate adaptors CDC20 and CDH1 to target proteins for proteasomal degradation. The APC(CDH1) substrate cyclin A is critical for the G1/S transition and, paradoxically, accumulates even when APC(CDH1) is active. We show that the deubiquitinase USP37 binds CDH1 and removes degradative polyubiquitin from cyclin A. USP37 was induced by E2F transcription factors in G1, peaked at G1/S, and was degraded in late mitosis. Phosphorylation of USP37 by CDK2 stimulated its full activity. USP37 overexpression caused premature cyclin A accumulation in G1 and accelerated S phase entry, whereas USP37 knockdown delayed these events. USP37 was inactive in mitosis because it was no longer phosphorylated by CDK2. Indeed, it switched from an antagonist to a substrate of APC(CDH1) and was modified with degradative K11-linked polyubiquitin.
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Affiliation(s)
- Xiaodong Huang
- Department of Physiological Chemistry, Genentech, Inc., 1 DNA Way, South San Francisco, CA 94080, USA
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19
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Meyer HJ, Rape M. Processive ubiquitin chain formation by the anaphase-promoting complex. Semin Cell Dev Biol 2011; 22:544-50. [PMID: 21477659 DOI: 10.1016/j.semcdb.2011.03.009] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2011] [Accepted: 03/16/2011] [Indexed: 12/11/2022]
Abstract
Progression through mitosis requires the sequential ubiquitination of cell cycle regulators by the anaphase-promoting complex, resulting in their proteasomal degradation. Although several mechanisms contribute to APC/C regulation during mitosis, the APC/C is able to discriminate between its many substrates by exploiting differences in the processivity of ubiquitin chain assembly. Here, we discuss how the APC/C achieves processive ubiquitin chain formation to trigger the sequential degradation of cell cycle regulators during mitosis.
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Affiliation(s)
- Hermann-Josef Meyer
- University of California at Berkeley, Department of Molecular and Cell Biology, Berkeley, CA 94720-3202, United States
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20
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van Ree JH, Jeganathan KB, Malureanu L, van Deursen JM. Overexpression of the E2 ubiquitin-conjugating enzyme UbcH10 causes chromosome missegregation and tumor formation. ACTA ACUST UNITED AC 2010; 188:83-100. [PMID: 20065091 PMCID: PMC2812857 DOI: 10.1083/jcb.200906147] [Citation(s) in RCA: 168] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
An overabundance of UbcH10 disrupts mitotic checkpoint signaling as a result of a degradation of cyclin B, increasing spontaneous and carcinogen-induced tumor formation in transgenic mice. The anaphase-promoting complex/cyclosome (APC/C) E3 ubiquitin ligase functions with the E2 ubiquitin–conjugating enzyme UbcH10 in the orderly progression through mitosis by marking key mitotic regulators for destruction by the 26-S proteasome. UbcH10 is overexpressed in many human cancer types and is associated with tumor progression. However, whether UbcH10 overexpression causes tumor formation is unknown. To address this central question and to define the molecular and cellular consequences of UbcH10 overexpression, we generated a series of transgenic mice in which UbcH10 was overexpressed in graded fashion. In this study, we show that UbcH10 overexpression leads to precocious degradation of cyclin B by the APC/C, supernumerary centrioles, lagging chromosomes, and aneuploidy. Importantly, we find that UbcH10 transgenic mice are prone to carcinogen-induced lung tumors and a broad spectrum of spontaneous tumors. Our results identify UbcH10 as a prominent protooncogene that causes whole chromosome instability and tumor formation over a wide gradient of overexpression levels.
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Affiliation(s)
- Janine H van Ree
- Department of Pediatric and Adolescent Medicine, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
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21
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Summers MK, Jackson PK. Biochemical analysis of the Anaphase Promoting Complex: activities of E2 enzymes and substrate competitive (pseudosubstrate) inhibitors. Methods Mol Biol 2009; 545:313-330. [PMID: 19475398 DOI: 10.1007/978-1-60327-993-2_20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The Anaphase Promoting Complex (APC) ubiquitin ligase is critical for multiple processes including cell cycle, development, meiosis, and senescence. The importance of regulation of the APC by substrate competitive (pseudosubstrate) inhibitors, such as Emi1 and BubR1, has recently been demonstrated. Substrate competitive inhibitors typically bind to enzymes via the same site as substrates, but by having any combination of increased enzyme affinity and low turnover numbers, are able to "clog" the ability of the enzyme to bind and turnover substrates. For the APC, these pseudosubstrates can both position and block the APC and have been well validated as critical regulators for the APC enzymes.We have found that the substrate competitive mechanism of inhibition is sensitive to the E2 activity driving APC catalyzed ubiquitination events. This chapter provides detailed protocols for multiple in vitro ubiquitination assays of increasing complexity and the use of pseudosubstrate inhibitors in these assays. These assays are instrumental in examining the use of E2 enzymes by the APC and the intimate relationship this has with pseudosubstrate inhibition.
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Affiliation(s)
- Matthew K Summers
- Department of Cellular Regulation, Genentech Inc., South San Francisco, CA, USA
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22
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Walker A, Acquaviva C, Matsusaka T, Koop L, Pines J. UbcH10 has a rate-limiting role in G1 phase but might not act in the spindle checkpoint or as part of an autonomous oscillator. J Cell Sci 2008; 121:2319-26. [PMID: 18559889 DOI: 10.1242/jcs.031591] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Ubiquitin-dependent proteolysis mediated by the anaphase-promoting complex/cyclosome (APC/C) ubiquitin ligase lies at the heart of the cell cycle. The APC/C targets mitotic cyclins for destruction in mitosis and G1 phase and is then inactivated at S phase, thereby generating the alternating states of high and low cyclin-Cdk activity required for the alternation of mitosis and DNA replication. Two key questions are how the APC/C is held in check by the spindle-assembly checkpoint to delay cells in mitosis in the presence of improperly attached chromosomes, and how the APC/C is inactivated once cells exit mitosis. The ubiquitin-conjugating protein UbcH10 has been proposed to be crucial in the answers to both questions. However, here we show that the behaviour of UbcH10 is inconsistent with both a crucial role in the spindle checkpoint and in inactivating the APC/C as part of an autonomous oscillator. Instead, we find that the rate-limiting role of UbcH10 is only at the end of G1 phase, just before DNA replication begins.
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Affiliation(s)
- Adam Walker
- Wellcome Trust/Cancer Research UK Gurdon Institute and Department of Zoology, University of Cambridge, Cambridge CB2 1QN, UK
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23
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Lin J, Raoof DA, Wang Z, Lin MY, Thomas DG, Greenson JK, Giordano TJ, Orringer MB, Chang AC, Beer DG, Lin L. Expression and effect of inhibition of the ubiquitin-conjugating enzyme E2C on esophageal adenocarcinoma. Neoplasia 2007; 8:1062-71. [PMID: 17217624 PMCID: PMC1783715 DOI: 10.1593/neo.05832] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Ubiquitin-dependent proteolysis of cyclins plays a critical role in cell cycle progression and tumorigenesis. We examined the expression of ubiquitin-conjugating enzyme E2C (UBE2C) during progression from Barrett's metaplasia to esophageal adenocarcinoma (EA) and the effects of targeting this enzyme on EA-derived cell lines. Using oligonucleotide microarrays UBE2C expression was elevated in 73% (11 of 15) of EAs relative to Barrett's metaplasia. Tissue microarray showed elevated UBE2C in 70% (7 of 10) of dysplastic samples and in 87% (58 of 67) of tumors relative to metaplastic samples. Transfection of dominant-negative UBE2C into Seg-1 cells decreased proliferation (P = .04) and increased mitotic arrest compared to vector controls (63.5% vs 6.8%; P < .001). Transfection of UBE2C small interfering RNA also caused inhibiton of cell proliferation and distortion of the cell cycle, with maximal increase of G(2) cells (155% of mock cells) at 72 hours and of S-phase cells (308% of mock cells) at 24 hours. Treatment of Seg-1 cells with the proteasome inhibitor MG-262 (1 nM-1 microM) showed decreased proliferation (P = .02). EA-derived cells expressing UBE2C are sensitive to treatment with MG-262 and to silencing of UBE2C, suggesting that patients with EAs overexpressing UBE2C may benefit from agents targeting this ubiquitin-conjugating enzyme.
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Affiliation(s)
- Jules Lin
- Section of General Thoracic Surgery, Department of Surgery, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Duna A Raoof
- Section of General Thoracic Surgery, Department of Surgery, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Zhuwen Wang
- Section of General Thoracic Surgery, Department of Surgery, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Mu-Yen Lin
- Division of Thoracic Surgery, Department of Surgery and Institute of Clinical Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Dafydd G Thomas
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Joel K Greenson
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Thomas J Giordano
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Mark B Orringer
- Section of General Thoracic Surgery, Department of Surgery, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Andrew C Chang
- Section of General Thoracic Surgery, Department of Surgery, University of Michigan Medical School, Ann Arbor, MI, USA
| | - David G Beer
- Section of General Thoracic Surgery, Department of Surgery, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Lin Lin
- Section of General Thoracic Surgery, Department of Surgery, University of Michigan Medical School, Ann Arbor, MI, USA
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24
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Ravid T, Hochstrasser M. Autoregulation of an E2 enzyme by ubiquitin-chain assembly on its catalytic residue. Nat Cell Biol 2007; 9:422-7. [PMID: 17310239 DOI: 10.1038/ncb1558] [Citation(s) in RCA: 130] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2007] [Accepted: 02/05/2007] [Indexed: 11/09/2022]
Abstract
Cells have quality-control mechanisms to recognize non-native protein structures and either help the proteins fold or promote their degradation. Ubiquitin-conjugating enzymes (E2s) and ubiquitin ligases (E3s) work together to assemble polyubiquitin chains on misfolded or misassembled proteins, which are then degraded by the proteasome. Here, we find that Ubc7, a yeast E2, can itself undergo degradation when its levels exceed that of its binding partner Cue1, a transmembrane protein that tethers Ubc7 to the endoplasmic reticulum. Unassembled, and thus mislocalized, Ubc7 is targeted to the proteasome by Ufd4, a homologous to E6-AP C-terminus (HECT)-class E3. Ubc7 is autoubiquitinated by a novel mechanism wherein the catalytic cysteine, instead of a lysine residue, provides the polyubiquitin chain acceptor site, and this cysteine-linked chain functions as a degradation signal. The polyubiquitin chain can also be transferred to a lysine side chain, suggesting a mechanism for polyubiquitin chain assembly that precedes substrate modification.
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Affiliation(s)
- Tommer Ravid
- Department of Molecular Biophysics & Biochemistry, Yale University, New Haven, CT 06520, USA
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25
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Peters JM. The anaphase promoting complex/cyclosome: a machine designed to destroy. Nat Rev Mol Cell Biol 2006; 7:644-56. [PMID: 16896351 DOI: 10.1038/nrm1988] [Citation(s) in RCA: 989] [Impact Index Per Article: 54.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The anaphase promoting complex/cyclosome (APC/C) is a ubiquitin ligase that has essential functions in and outside the eukaryotic cell cycle. It is the most complex molecular machine that is known to catalyse ubiquitylation reactions, and it contains more than a dozen subunits that assemble into a large 1.5-MDa complex. Recent discoveries have revealed an unexpected multitude of mechanisms that control APC/C activity, and have provided a first insight into how this unusual ubiquitin ligase recognizes its substrates.
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Affiliation(s)
- Jan-Michael Peters
- Research Institute of Molecular Pathology, Dr. Bohr-Gasse 7, A-1030 Vienna, Austria.
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26
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Havens CG, Ho A, Yoshioka N, Dowdy SF. Regulation of late G1/S phase transition and APC Cdh1 by reactive oxygen species. Mol Cell Biol 2006; 26:4701-11. [PMID: 16738333 PMCID: PMC1489138 DOI: 10.1128/mcb.00303-06] [Citation(s) in RCA: 144] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Proliferating cells have a higher metabolic rate than quiescent cells. To investigate the role of metabolism in cell cycle progression, we examined cell size, mitochondrial mass, and reactive oxygen species (ROS) levels in highly synchronized cell populations progressing from early G1 to S phase. We found that ROS steadily increased, compared to cell size and mitochondrial mass, through the cell cycle. Since ROS has been shown to influence cell proliferation and transformation, we hypothesized that ROS could contribute to cell cycle progression. Antioxidant treatment of cells induced a late-G1-phase cell cycle arrest characterized by continued cellular growth, active cyclin D-Cdk4/6 and active cyclin E-Cdk2 kinases, and inactive hyperphosphorylated pRb. However, antioxidant-treated cells failed to accumulate cyclin A protein, a requisite step for initiation of DNA synthesis. Further examination revealed that cyclin A continued to be ubiquitinated by the anaphase promoting complex (APC) and to be degraded by the proteasome. This antioxidant arrest could be rescued by overexpression of Emi1, an APC inhibitor. These observations reveal an intrinsic late-G1-phase checkpoint, after transition across the growth factor-dependent G1 restriction point, that links increased steady-state levels of endogenous ROS and cell cycle progression through continued activity of APC in association with Cdh1.
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Affiliation(s)
- Courtney G Havens
- Howard Hughes Medical Institute, Department of Cellular and Molecular Medicine, University of California-San Diego, School of Medicine, 9500 Gilman Dr., La Jolla, CA 92093-0686, USA
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27
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Pickart CM, Eddins MJ. Ubiquitin: structures, functions, mechanisms. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2005; 1695:55-72. [PMID: 15571809 DOI: 10.1016/j.bbamcr.2004.09.019] [Citation(s) in RCA: 964] [Impact Index Per Article: 50.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Ubiquitin is the founding member of a family of structurally conserved proteins that regulate a host of processes in eukaryotic cells. Ubiquitin and its relatives carry out their functions through covalent attachment to other cellular proteins, thereby changing the stability, localization, or activity of the target protein. This article reviews the basic biochemistry of these protein conjugation reactions, focusing on ubiquitin itself and emphasizing recent insights into mechanism and specificity.
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Affiliation(s)
- Cecile M Pickart
- Department of Biochemistry and Molecular Biology/Bloomberg School of Public Health, Johns Hopkins University, 615 North Wolfe Street, Baltimore, MD 21205, USA.
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28
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Abstract
Regulated protein degradation has emerged as a key recurring theme in multiple aspects of cell-cycle regulation. Importantly, the irreversible nature of proteolysis makes it an invaluable complement to the intrinsically reversible regulation through phosphorylation and other post-translational modifications. Consequently, ubiquitin-protein ligases, the protagonists of regulated protein destruction, have gained prominence that compares to that of the cyclin-dependent kinases (Cdks) in driving the eukaryotic cell-cycle clock. This review will focus on the two main players, the related ubiquitin-protein ligases APC/C and SCF, and how they control cell-cycle progression. I will also try to delineate the regulation and interplay of these destruction mechanisms, which are intricately connected to the kinase network as well as to extrinsic signals. Moreover, cell-cycle ubiquitin-protein ligases are themselves subject to proteolytic control in cis as well as in trans. Finally, a careful comparison of the functions and regulation of APC/C and SCF shows that, in certain aspects, their logic of action is fundamentally different.
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Affiliation(s)
- Hartmut C Vodermaier
- Research Institute of Molecular Pathology (IMP), Dr. Bohr-Gasse 7, A-1030 Vienna, Austria.
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29
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Máthé E, Kraft C, Giet R, Deák P, Peters JM, Glover DM. The E2-C vihar is required for the correct spatiotemporal proteolysis of cyclin B and itself undergoes cyclical degradation. Curr Biol 2005; 14:1723-33. [PMID: 15458643 DOI: 10.1016/j.cub.2004.09.023] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2004] [Revised: 07/08/2004] [Accepted: 08/02/2004] [Indexed: 10/26/2022]
Abstract
BACKGROUND Proteolytic degradation of mitotic regulatory proteins first requires these targets to be ubiquitinated. This is regulated at the level of conjugation of ubiquitin to substrates by the anaphase-promoting complex/cyclosome (APC/C) ubiquitin-protein ligase. Substrate specificity and temporal activity of the APC/C has been thought to lie primarily with its two activators, Cdc20/Fizzy and Cdh1/Fizzy-related. RESULTS Here, we show that reduction in the E2 ubiquitin-conjugating enzyme (UBC) of the E2-C family that is encoded by the Drosophila gene vihar (vih), by either mutation or RNAi, leads to an accumulation of cells in a metaphase-like state. Cyclin B accumulates to high levels in all mitotic vih cells, particularly at the spindle poles. Vihar E2-C is present in the cytoplasm of mitotic cells but also associates with centrosomes, and its own degradation is initiated at the metaphase-anaphase transition. Expression of destruction D box mutants of vihar in the syncytial embryo results in mitotic arrest at late anaphase. In contrast to hypomorphic mutants, Cyclin B is degraded at the spindle poles and accumulates in the equatorial region of the spindle. CONCLUSIONS In Drosophila, the Vihar E2 UBC contributes to the spatiotemporal control of Cyclin B degradation that first occurs at the spindle poles. APC/C-mediated proteolysis of Vihar E2-C autoinactivates the APC/C at the centrosome before a second wave of proteolysis to degrade Cyclin B on the rest of the spindle and elsewhere in the cell.
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Affiliation(s)
- Endre Máthé
- Cancer Research UK Cell Cycle Genetics Group, Department of Genetics, University of Cambridge, Downing Street, Cambridge CB2 3EH, UK
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30
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Rape M, Kirschner MW. Autonomous regulation of the anaphase-promoting complex couples mitosis to S-phase entry. Nature 2004; 432:588-95. [PMID: 15558010 DOI: 10.1038/nature03023] [Citation(s) in RCA: 239] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2004] [Accepted: 09/13/2004] [Indexed: 11/08/2022]
Abstract
Oscillations in cyclin-dependent kinase (CDK) activity drive the somatic cell cycle. After entry into mitosis, CDKs activate the anaphase-promoting complex (APC), which then promotes cyclin degradation and mitotic exit. The re-accumulation of cyclin A causes the inactivation of APC and entry into S phase, but how cyclin A can accumulate in the presence of active APC has remained unclear. Here we show that, during G1, APC autonomously switches to a state permissive for cyclin A accumulation. Crucial to this transition is the APC(Cdh1)-dependent autoubiquitination and proteasomal degradation of the ubiquitin-conjugating enzyme (E2) UbcH10. Because APC substrates inhibit the autoubiquitination of UbcH10, but not its E2 function, APC activity is maintained as long as G1 substrates are present. Thus, through UbcH10 degradation and cyclin A stabilization, APC autonomously downregulates its activity. This indicates that the core of the metazoan cell cycle could be described as a self-perpetuating but highly regulated oscillator composed of alternating CDK and APC activities.
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Affiliation(s)
- Michael Rape
- Department of Systems Biology, Harvard Medical School, 240 Longwood Avenue, Boston, Massachusetts 02115, USA
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31
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Wagner KW, Sapinoso LM, El-Rifai W, Frierson HF, Butz N, Mestan J, Hofmann F, Deveraux QL, Hampton GM. Overexpression, genomic amplification and therapeutic potential of inhibiting the UbcH10 ubiquitin conjugase in human carcinomas of diverse anatomic origin. Oncogene 2004; 23:6621-9. [PMID: 15208666 DOI: 10.1038/sj.onc.1207861] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Gene expression profiling of anatomically diverse carcinomas and their corresponding normal tissues was used to identify genes with cancer-associated expression. We show here that the ubiquitin conjugase, UbcH10, is significantly overexpressed in many different types of cancers and is associated with the degree of tumor differentiation in carcinomas of the breast, lung, ovary and bladder, as well as in glioblastomas. We also show that UbcH10 overexpression in gastro-esophageal, and probably other carcinomas may be a direct consequence of chromosomal amplification at the UbcH10 locus, 20q13.1, a region known to be amplified in diverse tumors. To evaluate whether inhibition of UbcH10 function may be therapeutically relevant in cancer, we used small interfering RNAs (siRNAs) to silence UbcH10 transcription selectively. Diminution of UbcH10 expression significantly inhibited both tumor and normal cell proliferation without inducing cell death. However, when combined with agonists of the DR5/TRAIL receptor, siRNAs directed against the UbcH10 transcript dramatically enhanced killing of cancer cells, but not of proliferating primary human epithelial cells or fibroblasts. Together, these data demonstrate that UbcH10 plays an important role in tumor development and that its inhibition in combination with agonists of the TRAIL receptor may provide an enhanced therapeutic index.
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Affiliation(s)
- Klaus W Wagner
- Genomics Institute of the Novartis Research Foundation, 10675 John Jay Hopkins Drive, San Diego, CA 92121, USA
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32
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Hu T, Gibson DP, Carr GJ, Torontali SM, Tiesman JP, Chaney JG, Aardema MJ. Identification of a gene expression profile that discriminates indirect-acting genotoxins from direct-acting genotoxins. Mutat Res 2004; 549:5-27. [PMID: 15120960 DOI: 10.1016/j.mrfmmm.2003.11.012] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2003] [Revised: 11/16/2003] [Accepted: 11/17/2003] [Indexed: 04/29/2023]
Abstract
During the safety evaluation process of new drugs and chemicals, a battery of genotoxicity tests is conducted starting with in vitro genotoxicity assays. Obtaining positive results in in vitro genotoxicity tests is not uncommon. Follow-up studies to determine the biological relevance of positive genotoxicity results are costly, time consuming, and utilize animals. More efficient methods, especially for identifying a putative mode of action like an indirect mechanism of genotoxicity (where DNA molecules are not the initial primary targets), would greatly improve the risk assessment for genotoxins. To this end, we are participating in an International Life Sciences Institute (ILSI) project involving studies of gene expression changes caused by model genotoxins. The purpose of the work is to evaluate gene expression tools in general, and specifically for discriminating genotoxins that are direct-acting from indirect-acting. Our lab has evaluated gene expression changes as well as micronuclei (MN) in L5178Y TK(+/-) mouse lymphoma cells treated with six compounds. Direct-acting genotoxins (where DNA is the initial primary target) that were evaluated included the DNA crosslinking agents, mitomycin C (MMC) and cisplatin (CIS), and an alkylating agent, methyl methanesulfonate (MMS). Indirect-acting genotoxins included hydroxyurea (HU), a ribonucleotide reductase inhibitor, taxol (TXL), a microtubule inhibitor, and etoposide (ETOP), a DNA topoisomerase II inhibitor. Microarray gene expression analysis was conducted using Affymetrix mouse oligonucleotide arrays on RNA samples derived from cells which were harvested immediately after the 4 h chemical treatment, and 20 h after the 4 h chemical treatment. The evaluation of these experimental results yields evidence of differentially regulated genes at both 4 and 24 h time points that appear to have discriminating power for direct versus indirect genotoxins, and therefore may serve as a fingerprint for classifying chemicals when their mechanism of action is unknown.
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Affiliation(s)
- Ting Hu
- The Procter and Gamble Company, Miami Valley Laboratories, P.O. Box 538707 09, Cincinnati, OH 45253-8707, USA
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33
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Listovsky T, Oren YS, Yudkovsky Y, Mahbubani HM, Weiss AM, Lebendiker M, Brandeis M. Mammalian Cdh1/Fzr mediates its own degradation. EMBO J 2004; 23:1619-26. [PMID: 15029244 PMCID: PMC391060 DOI: 10.1038/sj.emboj.7600149] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2003] [Accepted: 02/09/2004] [Indexed: 11/08/2022] Open
Abstract
The Anaphase-Promoting Complex/Cyclosome (APC/C) ubiquitin ligase mediates degradation of cell cycle proteins during mitosis and G1. Cdc20/Fzy and Cdh1/Fzr are substrate-specific APC/C activators. The level of mammalian Cdh1 is high in mitosis, but it is inactive and does not bind the APC/C. We show that when Cdh1 is active in G1 and G0, its levels are considerably lower and almost all of it is APC/C associated. We demonstrate that Cdh1 is subject to APC/C-specific degradation in G1 and G0, and that this degradation depends upon two RXXL-type destruction boxes. We further demonstrate that addition of Cdh1 to Xenopus interphase extracts, which have an inactive APC/C, activates it to degrade Cdh1. These observations indicate that Cdh1 mediates its own degradation by activating the APC/C to degrade itself. Elevated levels of Cdh1 are deleterious for cell cycle progression in various organisms. This auto-regulation of Cdh1 could thus play a role in ensuring that the level of Cdh1 is reduced during G1 and G0, allowing it to be switched off at the correct time.
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Affiliation(s)
- Tamar Listovsky
- Department of Genetics, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Yifat S Oren
- Department of Genetics, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Yana Yudkovsky
- Unit of Biochemistry, The Rappaport Institute of Medical Research, The Technion-Israel Institute for Technology, Haifa, Israel
| | - Hiro M Mahbubani
- Cancer Research-UK, Clare Hall Laboratories, South Mimms, Herts, UK
| | - Aryeh M Weiss
- Department of Genetics, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
- School of Engineering, Bar Ilan University, Ramat Gan, Israel
| | - Mario Lebendiker
- Protein Purification Unit, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Michael Brandeis
- Department of Genetics, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
- Cancer Research-UK, Clare Hall Laboratories, South Mimms, Herts, UK
- Department of Genetics, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel. Tel: +972 2 6585123; Fax: +972 2 6586975; E-mail:
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34
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Gabellini D, Colaluca IN, Vodermaier HC, Biamonti G, Giacca M, Falaschi A, Riva S, Peverali FA. Early mitotic degradation of the homeoprotein HOXC10 is potentially linked to cell cycle progression. EMBO J 2003; 22:3715-24. [PMID: 12853486 PMCID: PMC165610 DOI: 10.1093/emboj/cdg340] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Hox proteins are transcription factors involved in controlling axial patterning, leukaemias and hereditary malformations. Here, we show that HOXC10 oscillates in abundance during the cell cycle, being targeted for degradation early in mitosis by the ubiquitin-dependent proteasome pathway. Among abdominal-B subfamily members, the mitotic proteolysis of HOXC10 appears unique, since the levels of the paralogous HOXD10 and the related homeoprotein HOXC13 are constant throughout the cell cycle. When two destruction box motifs (D-box) are mutated, HOXC10 is stabilized and cells accumulate in metaphase. HOXC10 appears to be a new prometaphase target of the anaphase-promoting complex (APC), since its degradation coincides with cyclin A destruction and is suppressed by expression of a dominant-negative form of UbcH10, an APC-associated ubiquitin-conjugating enzyme. Moreover, HOXC10 co-immunoprecipitates the APC subunit CDC27, and its in vitro degradation is reduced in APC-depleted extracts or by competition with the APC substrate cyclin A. These data imply that HOXC10 is a homeoprotein with the potential to influence mitotic progression, and might provide a link between developmental regulation and cell cycle control.
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Affiliation(s)
- Davide Gabellini
- Istituto di Genetica Molecolare, CNR, via Abbiategrasso 207,I-27100 Pavia, Italy
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Fay DS, Large E, Han M, Darland M. lin-35/Rb and ubc-18, an E2 ubiquitin-conjugating enzyme, function redundantly to control pharyngeal morphogenesis in C. elegans. Development 2003; 130:3319-30. [PMID: 12783801 DOI: 10.1242/dev.00561] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The retinoblastoma gene product has been implicated in the regulation of multiple cellular and developmental processes, including a well-defined role in the control of cell cycle progression. The Caenorhabditis elegans retinoblastoma protein homolog, LIN-35, is also a key regulator of cell cycle entry and, as shown by studies of synthetic multivulval genes, plays an important role in the determination of vulval cell fates. We demonstrate an additional and unexpected function for lin-35 in organ morphogenesis. Using a genetic approach to isolate lin-35 synthetic-lethal mutations, we have identified redundant roles for lin-35 and ubc-18, a gene that encodes an E2 ubiquitin-conjugating enzyme closely related to human UBCH7. lin-35 and ubc-18 cooperate to control one or more steps during pharyngeal morphogenesis. Based on genetic and phenotypic analyses, this role for lin-35 in pharyngeal morphogenesis appears to be distinct from its cell cycle-related functions. lin-35 and ubc-18 may act in concert to regulate the levels of one or more critical targets during C. elegans development.
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Affiliation(s)
- David S Fay
- Department of Molecular Biology, University of Wyoming, PO Box 3944, Laramie, WY 82071-3944, USA.
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36
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Criqui MC, de Almeida Engler J, Camasses A, Capron A, Parmentier Y, Inzé D, Genschik P. Molecular characterization of plant ubiquitin-conjugating enzymes belonging to the UbcP4/E2-C/UBCx/UbcH10 gene family. PLANT PHYSIOLOGY 2002; 130:1230-40. [PMID: 12427990 PMCID: PMC166644 DOI: 10.1104/pp.011353] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2002] [Accepted: 08/07/2002] [Indexed: 05/04/2023]
Abstract
The anaphase promoting complex or cyclosome is the ubiquitin-ligase that targets destruction box-containing proteins for proteolysis during the cell cycle. Anaphase promoting complex or cyclosome and its activator (the fizzy and fizzy-related) proteins work together with ubiquitin-conjugating enzymes (UBCs) (E2s). One class of E2s (called E2-C) seems specifically involved in cyclin B1 degradation. Although it has recently been shown that mammalian E2-C is regulated at the protein level during the cell cycle, not much is known concerning the expression of these genes. Arabidopsis encodes two genes belonging to the E2-C gene family (called UBC19 and UBC20). We found that UBC19 is able to complement fission yeast (Schizosaccharomyces pombe) UbcP4-140 mutant, indicating that the plant protein can functionally replace its yeast ortholog for protein degradation during mitosis. In situ hybridization experiments were performed to study the expression of the E2-C genes in various tissues of plants. Their transcripts were always, but not exclusively, found in tissues active for cell division. Thus, the UBC19/20 E2s may have a key function during cell cycle, but may also be involved in ubiquitylation reactions occurring during differentiation and/or in differentiated cells. Finally, we showed that a translational fusion protein between UBC19 and green fluorescent protein localized both in the cytosol and the nucleus in stable transformed tobacco (Nicotiana tabacum cv Bright Yellow 2) cells.
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Affiliation(s)
- Marie Claire Criqui
- Institut de Biologie Moléculaire des Plantes du Centre National de la Recherche Scientifique, 12 rue du Général Zimmer, 67084 Strasbourg cedex, France
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37
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Zur A, Brandeis M. Timing of APC/C substrate degradation is determined by fzy/fzr specificity of destruction boxes. EMBO J 2002; 21:4500-10. [PMID: 12198152 PMCID: PMC126191 DOI: 10.1093/emboj/cdf452] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The anaphase promoting complex/cyclosome (APC/C), activated by fzy and fzr, degrades cell cycle proteins that carry RXXL or KEN destruction boxes (d-boxes). APC/C substrates regulate sequential events and must be degraded in the correct order during mitosis and G(1). We studied how d-boxes determine APC/C(fzy)/APC/C(fzr) specificity and degradation timing. Cyclin B1 has an RXXL box and is degraded by both APC/C(fzy) and APC/C(fzr); fzy has a KEN box and is degraded by APC/C(fzr) only. We characterized the degradation of substrates with swapped d-boxes. Cyclin B1 with KEN was degraded by APC/C(fzr) only. Fzy with RXXL could be degraded by APC/C(fzy) and APC/C(fzr). Interestingly, APC/C(fzy)- but not APC/C(fzr)-specific degradation is highly dependent on the location of RXXL. We studied degradation of tagged substrates in real time and observed that APC/C(fzr) is activated in early G(1). These observations demonstrate how d-box specificities of APC/C(fzy) and APC/C(fzr), and the successive activation of APC/C by fzy and fzr, establish the temporal degradation pattern. Our observations can explain further why some endogenous RXXL substrates are degraded by APC/C(fzy), while others are restricted to APC/C(fzr).
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Affiliation(s)
| | - Michael Brandeis
- Department of Genetics, Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
Corresponding author e-mail:
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38
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Lin Y, Hwang WC, Basavappa R. Structural and functional analysis of the human mitotic-specific ubiquitin-conjugating enzyme, UbcH10. J Biol Chem 2002; 277:21913-21. [PMID: 11927573 DOI: 10.1074/jbc.m109398200] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cell cycle progression is controlled at several different junctures by the targeted destruction of cell cycle regulatory proteins. These carefully orchestrated events include the destruction of the securin protein to permit entry into anaphase, and the destruction of cyclin B to permit exit from mitosis. These destruction events are mediated by the ubiquitin/proteasome system. The human ubiquitin-conjugating enzyme, UbcH10, is an essential mediator of the mitotic destruction events. We report here the 1.95-A crystal structure of a mutant UbcH10, in which the active site cysteine has been replaced with a serine. Functional analysis indicates that the mutant is active in accepting ubiquitin, although not as efficiently as wild-type. Examination of the crystal structure reveals that the NH2-terminal extension in UbcH10 is disordered and that a conserved 3(10)-helix places a lysine residue near the active site. Analysis of relevant mutants demonstrates that for ubiquitin-adduct formation the presence or absence of the NH2-terminal extension has little effect, whereas the lysine residue near the active site has significant effect. The structure provides additional insight into UbcH10 function including possible sites of interaction with the anaphase promoting complex/cyclosome and the disposition of a putative destruction box motif in the structure.
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Affiliation(s)
- Yaqiong Lin
- Department of Biochemistry and Biophysics, University of Rochester Medical Center, Rochester, New York 14642, USA
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39
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Abstract
Key events in mitosis such as sister chromatid separation and subsequent inactivation of cyclin-dependent kinase 1 are regulated by ubiquitin-dependent proteolysis. These events are mediated by the anaphase-promoting complex (APC), a cell cycle-regulated ubiquitin ligase that assembles multiubiquitin chains on regulatory proteins such as securin and cyclins and thereby targets them for destruction by the 26S proteasome.
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Affiliation(s)
- Jan-Michael Peters
- Research Institute of Molecular Pathology, Dr.-Bohr Gasse 7, A-1030 Vienna, Austria.
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40
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Abstract
The conjugation of ubiquitin to other cellular proteins regulates a broad range of eukaryotic cell functions. The high efficiency and exquisite selectivity of ubiquitination reactions reflect the properties of enzymes known as ubiquitin-protein ligases or E3s. An E3 recognizes its substrates based on the presence of a specific ubiquitination signal, and catalyzes the formation of an isopeptide bond between a substrate (or ubiquitin) lysine residue and the C terminus of ubiquitin. Although a great deal is known about the molecular basis of E3 specificity, much less is known about molecular mechanisms of catalysis by E3s. Recent findings reveal that all known E3s utilize one of just two catalytic domains--a HECT domain or a RING finger--and crystal structures have provided the first detailed views of an active site of each type. The new findings shed light on many aspects of E3 structure, function, and mechanism, but also emphasize that key features of E3 catalysis remain to be elucidated.
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Affiliation(s)
- C M Pickart
- School of Public Health, Johns Hopkins University, 615 North Wolfe Street, Baltimore, Maryland 21205, USA.
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41
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Chan AH, Lee SM, Chim SS, Kok LD, Waye MM, Lee CY, Fung KP, Tsui SK. Molecular cloning and characterization of a RING-H2 finger protein, ANAPC11, the human homolog of yeast Apc11p. J Cell Biochem 2001; 83:249-58. [PMID: 11573242 DOI: 10.1002/jcb.1217] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Yeast Apc11p together with Rbx1 and Roc2/SAG define a new class of RING-H2 fingers in a superfamily of E3 ubiquitin ligases. The human homolog of Apc11p, ANAPC11 was identified during a large-scale partial sequencing of a human liver cancer cDNA library and partial characterization was performed. This 514 bp full-length cDNA has a predicted open reading frame (ORF) encoding 84 amino acids. The ORF codes for ANAPC11, the human anaphase promoting complex subunit 11 (yeast APC11 homolog), which possesses a RING-H2 finger motif and exhibits sequence similarity to subunits of E3 ubiquitin ligase complexes. In Northern blot hybridization with poly(A) RNA of various human tissues using radio-labelled ANAPC11 cDNA probe, we found strong signals detected in skeletal muscle and heart; moderate signals detected in brain, kidney, and liver; and detectable but low signals in colon, thymus, spleen, small intestine, placenta, lung, and peripheral blood leukocyte. The ANAPC11 gene is located at the human chromosome 17q25. ANAPC11 is distributed diffusely in the cytoplasm and nucleus with discrete accumulation in granular structures in all the cell lines (AML 12, HepG2, and C2C12) transfected. Expression level of ANAPC11 is found higher in certain types of cancer determined in the RNA dot blot experiment.
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Affiliation(s)
- A H Chan
- Department of Biochemistry, The Chinese University of Hong Kong, Shatin, NT, Hong Kong
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