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Hou XN, Tang C. The pros and cons of ubiquitination on the formation of protein condensates. Acta Biochim Biophys Sin (Shanghai) 2023; 55:1084-1098. [PMID: 37294105 PMCID: PMC10423694 DOI: 10.3724/abbs.2023096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Accepted: 03/19/2023] [Indexed: 06/10/2023] Open
Abstract
Ubiquitination, a post-translational modification that attaches one or more ubiquitin (Ub) molecules to another protein, plays a crucial role in the phase-separation processes. Ubiquitination can modulate the formation of membrane-less organelles in two ways. First, a scaffold protein drives phase separation, and Ub is recruited to the condensates. Second, Ub actively phase-separates through the interactions with other proteins. Thus, the role of ubiquitination and the resulting polyUb chains ranges from bystanders to active participants in phase separation. Moreover, long polyUb chains may be the primary driving force for phase separation. We further discuss that the different roles can be determined by the lengths and linkages of polyUb chains which provide preorganized and multivalent binding platforms for other client proteins. Together, ubiquitination adds a new layer of regulation for the flow of material and information upon cellular compartmentalization of proteins.
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Affiliation(s)
- Xue-Ni Hou
- Beijing National Laboratory for Molecular SciencesCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing100871China
| | - Chun Tang
- Beijing National Laboratory for Molecular SciencesCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing100871China
- Center for Quantitate BiologyPKU-Tsinghua Center for Life ScienceAcademy for Advanced Interdisciplinary StudiesPeking UniversityBeijing100871China
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2
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Analysis and prediction of protein stability based on interaction network, gene ontology, and KEGG pathway enrichment scores. BIOCHIMICA ET BIOPHYSICA ACTA. PROTEINS AND PROTEOMICS 2023; 1871:140889. [PMID: 36610583 DOI: 10.1016/j.bbapap.2023.140889] [Citation(s) in RCA: 32] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Revised: 12/18/2022] [Accepted: 01/02/2023] [Indexed: 01/06/2023]
Abstract
Metabolic stability of proteins plays a vital role in various dedicated cellular processes. Traditional methods of measuring the metabolic stability are time-consuming and expensive. Therefore, we developed a more efficient computational approach to understand the protein dynamic action mechanisms in biological process networks. In this study, we collected 341 short-lived proteins and 824 non-short-lived proteins from U2OS; 342 short-lived proteins and 821 non-short-lived proteins from HEK293T; 424 short-lived proteins and 1153 non-short-lived proteins from HCT116; and 384 short-lived proteins and 992 non-short-lived proteins from RPE1. The proteins were encoded by GO and KEGG enrichment scores based on the genes and their neighbors in STRING, resulting in 20,681 GO term features and 297 KEGG pathway features. We also incorporated the protein interaction information from STRING into the features and obtained 19,247 node features. Boruta and mRMR methods were used for feature filtering, and IFS method was used to obtain the best feature subsets and create the models with the highest performance. The present study identified 42 features that did not appear in previous studies and classified them into eight groups according to their functional annotation. By reviewing the literature, we found that the following three functional groups were critical in determining the stability of proteins: synaptic transmission, post-translational modifications, and cell fate determination. These findings may serve as a valuable reference for developing drugs that target protein stability.
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3
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White LJ, Russell AJ, Pizzey AR, Dasmahapatra KK, Pownall ME. The Presence of Two MyoD Genes in a Subset of Acanthopterygii Fish Is Associated with a Polyserine Insert in MyoD1. J Dev Biol 2023; 11:jdb11020019. [PMID: 37218813 DOI: 10.3390/jdb11020019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 04/20/2023] [Accepted: 04/26/2023] [Indexed: 05/24/2023] Open
Abstract
The MyoD gene was duplicated during the teleost whole genome duplication and, while a second MyoD gene (MyoD2) was subsequently lost from the genomes of some lineages (including zebrafish), many fish lineages (including Alcolapia species) have retained both MyoD paralogues. Here we reveal the expression patterns of the two MyoD genes in Oreochromis (Alcolapia) alcalica using in situ hybridisation. We report our analysis of MyoD1 and MyoD2 protein sequences from 54 teleost species, and show that O. alcalica, along with some other teleosts, include a polyserine repeat between the amino terminal transactivation domains (TAD) and the cysteine-histidine rich region (H/C) in MyoD1. The evolutionary history of MyoD1 and MyoD2 is compared to the presence of this polyserine region using phylogenetics, and its functional relevance is tested using overexpression in a heterologous system to investigate subcellular localisation, stability, and activity of MyoD proteins that include and do not include the polyserine region.
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Affiliation(s)
- Lewis J White
- Biology Department, University of York, York YO10 5DD, UK
| | | | | | | | - Mary E Pownall
- Biology Department, University of York, York YO10 5DD, UK
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4
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Combs LR, Spires LM, Alonso JD, Papp B, Toth Z. KSHV RTA Induces Degradation of the Host Transcription Repressor ID2 To Promote the Viral Lytic Cycle. J Virol 2022; 96:e0010122. [PMID: 35604218 PMCID: PMC9215225 DOI: 10.1128/jvi.00101-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 05/05/2022] [Indexed: 11/20/2022] Open
Abstract
The immediate early viral protein replication and transcription activator (RTA) of Kaposi's sarcoma-associated herpesvirus (KSHV) is essential for activating the lytic cycle of KSHV. RTA induces the KSHV lytic cycle by several mechanisms, acting as a viral transcription factor that directly induces viral and host genes and acting as a viral E3 ubiquitin ligase by degrading host proteins that block viral lytic replication. Recently, we have characterized the global gene expression changes in primary effusion lymphoma (PEL) upon lytic reactivation of KSHV, which also led to the identification of rapidly downregulated genes such as ID2, an inhibitor of basic helix-loop-helix transcription factors. Here, we demonstrate that ID2 overexpression in PEL ablates KSHV lytic reactivation, indicating that ID2 inhibits the KSHV lytic cycle. Furthermore, we show that while ID2 is highly expressed during latency, its protein level is rapidly reduced by 4 h postinduction during lytic reactivation. Our results indicate that RTA binds to ID2 and induces its degradation during the KSHV lytic cycle by N-terminal ubiquitination through the ubiquitin-proteasome pathway. Importantly, we found that not only KSHV RTA but also its Epstein-Barr virus (EBV) and murine gammaherpesvirus 68 (MHV68) homologs interact with ID2, and they can induce the degradation of all four members of the ID protein family, suggesting an evolutionarily conserved interplay between gammaherpesvirus RTAs and ID proteins. Taken together, we propose that ID2 acts as a repressor of the KSHV lytic cycle, which is counteracted by its RTA-mediated degradation. We also predict that ID proteins may act as restriction factors of the lytic phase of the other gammaherpesviruses as well. IMPORTANCE In addition to its transcription regulatory role, RTA is also known to have an E3 ubiquitin ligase activity, which RTA utilizes for inducing protein degradation. However, it is still largely unknown what host factors are downregulated during KSHV lytic reactivation by RTA-mediated protein degradation and what the biological significance of the degradation of these host factors is. In this study, we discovered that RTA employs N-terminal ubiquitination to induce degradation of ID2, a potent transcription repressor of host genes, via the ubiquitin-proteasome pathway to promote KSHV lytic reactivation in PEL cells. Furthermore, we found that not only KSHV RTA but also RTA of EBV and MHV68 gammaherpesviruses can induce the degradation of all four human ID proteins, indicating that the interplay between gammaherpesvirus RTAs and ID proteins is evolutionarily conserved.
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Affiliation(s)
- Lauren R. Combs
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, Florida, USA
| | - Lauren McKenzie Spires
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, Florida, USA
| | - Juan D. Alonso
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, Florida, USA
| | - Bernadett Papp
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, Florida, USA
- University of Florida Genetics Institute, Gainesville, Florida, USA
- University of Florida Health Cancer Center, Gainesville, Florida, USA
- University of Florida Center for Orphaned Autoimmune Disorders, Gainesville, Florida, USA
- University of Florida Informatics Institute, Gainesville, Florida, USA
| | - Zsolt Toth
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, Florida, USA
- University of Florida Genetics Institute, Gainesville, Florida, USA
- University of Florida Health Cancer Center, Gainesville, Florida, USA
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5
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Proulx J, Borgmann K, Park IW. Post-translational modifications inducing proteasomal degradation to counter HIV-1 infection. Virus Res 2020; 289:198142. [PMID: 32882242 DOI: 10.1016/j.virusres.2020.198142] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Revised: 08/20/2020] [Accepted: 08/21/2020] [Indexed: 12/14/2022]
Abstract
Post-translational modifications (PTMs) are integral to regulating a wide variety of cellular processes in eukaryotic cells, such as regulation of protein stability, alteration of celluar location, protein activity modulation, and regulation of protein interactions. HIV-1, like other eukaryotic viruses, and its infected host exploit the proteasomal degradation system for their respective proliferation and survival, using various PTMs, including but not limited to ubiquitination, SUMOylation, NEDDylation, interferon-stimulated gene (ISG)ylation. Essentially all viral proteins within the virions -- and in the HIV-1-infected cells -- interact with their cellular counterparts for this degradation, utilizing ubiquitin (Ub), and the Ub-like (Ubl) modifiers less frequently, to eliminate the involved proteins throughout the virus life cycle, from the entry step to release of the assembled virus particles. Such interplay is pivotal for, on the one hand, the cell to restrict proliferation of the infecting virus, and on the other, for molecular counteraction by the virus to overcome this cellular protein-imposed restriction. Recent reports indicate that not only viral/cellular proteins but also viral/viral protein interactions play vital roles in regulating viral protein stability. We hence give an overview of the molecular processes of PTMs involved in proteasomal degradation of the viral and cellular proteins, and the viral/viral and viral/cellular protein interplay in restriction and competition for HIV-1 vs. host cell survival. Insights in this realm could open new avenues for developing therapeutics against HIV-1 via targeting specific steps of the proteasome degradation pathway during the HIV-1 life cycle.
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Affiliation(s)
- Jessica Proulx
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX, 76107, United States
| | - Kathleen Borgmann
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX, 76107, United States
| | - In-Woo Park
- Microbiology, Immunology, and Genetics, University of North Texas Health Science Center, Fort Worth, TX, 76107, United States.
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6
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Mendes ML, Fougeras MR, Dittmar G. Analysis of ubiquitin signaling and chain topology cross-talk. J Proteomics 2020; 215:103634. [PMID: 31918034 DOI: 10.1016/j.jprot.2020.103634] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 12/13/2019] [Accepted: 01/05/2020] [Indexed: 12/12/2022]
Abstract
Protein ubiquitination is a powerful post-translational modification implicated in many cellular processes. Although ubiquitination is associated with protein degradation, depending on the topology of polyubiquitin chains, protein ubiquitination is connected to non-degradative events in DNA damage response, cell cycle control, immune response, trafficking, intracellular localization, and vesicle fusion events. It has been shown that a ubiquitin chain can contain two or more topologies at the same time. These branched chains add another level of complexity to ubiquitin signaling, increasing its versatility and specificity. Mass spectrometry-based proteomics has been playing an important role in the identification of all types of ubiquitin chains and linkages. This review aims to provide an overview of ubiquitin chain topology and associated signaling pathways and discusses the MS-based proteomic methodologies used to determine such topologies. SIGNIFICANCE: Ubiquitination plays important roles in many cellular processes. Proteins can be monoubiquitinated or polyubiquitinated forming non-branched or branched chains in a high number of possible combinations, each associated with different cellular processes. The detection and the topology of ubiquitin chains is thus of extreme importance in order to explain such processes. Advances in mass spectrometry based proteomics allowed for the discovery and topology mapping of many ubiquitin chains. This review revisits the state of the art in ubiquitin chain identification by mass spectrometry and gives an insight on the implication of such chains in many cellular processes.
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Affiliation(s)
- Marta L Mendes
- Proteomics of Cellular Signaling, Quantitative Biology Unit, Luxembourg Institute of Health, 1a Rue Thomas Edison, 1445 Strassen, Luxembourg
| | - Miriam R Fougeras
- Proteomics of Cellular Signaling, Quantitative Biology Unit, Luxembourg Institute of Health, 1a Rue Thomas Edison, 1445 Strassen, Luxembourg; Faculty of Science, Technology and Communication, University of Luxembourg, 2 avenue de l'Université, 4365, Esch-sur-Alzette, Luxembourg
| | - Gunnar Dittmar
- Proteomics of Cellular Signaling, Quantitative Biology Unit, Luxembourg Institute of Health, 1a Rue Thomas Edison, 1445 Strassen, Luxembourg; Faculty of Science, Technology and Communication, University of Luxembourg, 2 avenue de l'Université, 4365, Esch-sur-Alzette, Luxembourg.
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7
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Liu XH, De Gasperi R, Bauman WA, Cardozo CP. Nandrolone-induced nuclear accumulation of MyoD protein is mediated by Numb, a Notch inhibitor, in C2C12 myoblasts. Physiol Rep 2018; 6. [PMID: 29333723 PMCID: PMC5789652 DOI: 10.14814/phy2.13520] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 10/26/2017] [Accepted: 10/27/2017] [Indexed: 11/24/2022] Open
Abstract
Signaling via the androgen receptor (AR) stimulates myogenic progenitor differentiation. In addition, myogenic differentiation factor D (MyoD) and Numb, a Notch inhibitor, play key roles in regulating myogenic differentiation. Nandrolone, an anabolic steroid, upregulates both MyoD and Numb expression in myogenic cells. However, the molecular mechanisms by which MyoD is upregulated by nandrolone are unclear. Moreover, the potential crosstalk between nandrolone, MyoD, and Numb is not well understood. With these considerations in mind, we examined the effects of nandrolone on the expression of MyoD mRNA and protein, and determined the interactions of MyoD and Numb in the presence or absence of nandrolone in differentiating C2C12 myoblasts. Nandrolone increased MyoD mRNA and protein expression and significantly enhanced nuclear translocation of MyoD protein. The later effect of nandrolone was blunted by siRNA against Numb. Immunoprecipitation (IP) studies confirmed that Numb forms complexes with MyoD. Chromatin IP revealed that in the presence of nandrolone, Numb is recruited to a region of the MyH7 promotor containing the E‐box to which MyoD binds. These data indicate that nandrolone‐regulated MyoD activation occurs mainly through a posttranslational mechanism which promotes MyoD nuclear accumulation, and suggest that this effect of nandrolone is, at least in part, mediated by Numb.
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Affiliation(s)
- Xin-Hua Liu
- National Center for the Medical Consequences of Spinal Cord Injury, James J. Peter VA Medical Center, Bronx, New York.,Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Rita De Gasperi
- National Center for the Medical Consequences of Spinal Cord Injury, James J. Peter VA Medical Center, Bronx, New York.,Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, New York
| | - William A Bauman
- National Center for the Medical Consequences of Spinal Cord Injury, James J. Peter VA Medical Center, Bronx, New York.,Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York.,Department of Rehabilitation Medicine, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Christopher P Cardozo
- National Center for the Medical Consequences of Spinal Cord Injury, James J. Peter VA Medical Center, Bronx, New York.,Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York.,Department of Rehabilitation Medicine, Icahn School of Medicine at Mount Sinai, New York, New York.,Department of Pharmacologic Sciences, Icahn School of Medicine at Mount Sinai, New York, New York
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8
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Lysine-Less Variants of Spinal Muscular Atrophy SMN and SMNΔ7 Proteins Are Degraded by the Proteasome Pathway. Int J Mol Sci 2017; 18:ijms18122667. [PMID: 29292768 PMCID: PMC5751269 DOI: 10.3390/ijms18122667] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Revised: 11/30/2017] [Accepted: 12/04/2017] [Indexed: 11/17/2022] Open
Abstract
Spinal muscular atrophy is due to mutations affecting the SMN1 gene coding for the full-length protein (survival motor neuron; SMN) and the SMN2 gene that preferentially generates an exon 7-deleted protein (SMNΔ7) by alternative splicing. To study SMN and SMNΔ7 degradation in the cell, we have used tagged versions at the N- (Flag) or C-terminus (V5) of both proteins. Transfection of those constructs into HeLa cells and treatment with cycloheximide showed that those protein constructs were degraded. Proteasomal degradation usually requires prior lysine ubiquitylation. Surprisingly, lysine-less variants of both proteins tagged either at N- (Flag) or C-terminus (V5) were also degraded. The degradation of the endogenous SMN protein, and the protein constructs mentioned above, was mediated by the proteasome, as it was blocked by lactacystin, a specific and irreversible proteasomal inhibitor. The results obtained allowed us to conclude that SMN and SMNΔ7 proteasomal degradation did not absolutely require internal ubiquitylation nor N-terminal ubiquitylation (prevented by N-terminal tagging). While the above conclusions are firmly supported by the experimental data presented, we discuss and justify the need of deep proteomic techniques for the study of SMN complex components (orphan and bound) turn-over to understand the physiological relevant mechanisms of degradation of SMN and SMNΔ7 in the cell.
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9
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Geffen Y, Appleboim A, Gardner RG, Friedman N, Sadeh R, Ravid T. Mapping the Landscape of a Eukaryotic Degronome. Mol Cell 2016; 63:1055-65. [PMID: 27618491 DOI: 10.1016/j.molcel.2016.08.005] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 07/11/2016] [Accepted: 08/02/2016] [Indexed: 12/16/2022]
Abstract
The ubiquitin-proteasome system (UPS) for protein degradation has been under intensive study, and yet, we have only partial understanding of mechanisms by which proteins are selected to be targeted for proteolysis. One of the obstacles in studying these recognition pathways is the limited repertoire of known degradation signals (degrons). To better understand what determines the susceptibility of intracellular proteins to degradation by the UPS, we developed an unbiased method for large-scale identification of eukaryotic degrons. Using a reporter-based high-throughput competition assay, followed by deep sequencing, we measured a degradation potency index for thousands of native polypeptides in a single experiment. We further used this method to identify protein quality control (PQC)-specific and compartment-specific degrons. Our method provides an unprecedented insight into the yeast degronome, and it can readily be modified to study protein degradation signals and pathways in other organisms and in various settings.
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Affiliation(s)
- Yifat Geffen
- Department of Biological Chemistry, Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel
| | - Alon Appleboim
- Department of Biological Chemistry, Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel; School of Computer Science and Engineering, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel
| | - Richard G Gardner
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA
| | - Nir Friedman
- Department of Biological Chemistry, Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel; School of Computer Science and Engineering, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel.
| | - Ronen Sadeh
- Department of Biological Chemistry, Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel; School of Computer Science and Engineering, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel.
| | - Tommer Ravid
- Department of Biological Chemistry, Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel.
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10
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McDowell G, Philpott A. New Insights Into the Role of Ubiquitylation of Proteins. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2016; 325:35-88. [DOI: 10.1016/bs.ircmb.2016.02.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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11
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McDowell GS, Philpott A. Non-canonical ubiquitylation: mechanisms and consequences. Int J Biochem Cell Biol 2013; 45:1833-42. [PMID: 23732108 DOI: 10.1016/j.biocel.2013.05.026] [Citation(s) in RCA: 113] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Revised: 05/10/2013] [Accepted: 05/22/2013] [Indexed: 01/04/2023]
Abstract
Post-translational protein modifications initiate, regulate, propagate and terminate a wide variety of processes in cells, and in particular, ubiquitylation targets substrate proteins for degradation, subcellular translocation, cell signaling and multiple other cellular events. Modification of substrate proteins is widely observed to occur via covalent linkages of ubiquitin to the amine groups of lysine side-chains. However, in recent years several new modes of ubiquitin chain attachment have emerged. For instance, covalent modification of non-lysine sites in substrate proteins is theoretically possible according to basic chemical principles underlying the ubiquitylation process, and evidence is building that sites such as the N-terminal amine group of a protein, the hydroxyl group of serine and threonine residues and even the thiol groups of cysteine residues are all employed as sites of ubiquitylation. However, the potential importance of this "non-canonical ubiquitylation" of substrate proteins on sites other than lysine residues has been largely overlooked. This review aims to highlight the unusual features of the process of non-canonical ubiquitylation and the consequences of these events on the activity and fate of a protein.
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Affiliation(s)
- Gary S McDowell
- Department of Oncology, University of Cambridge, Hutchison/Medical Research Council (MRC) Research Centre, Cambridge, UK
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12
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Bichsel C, Neeld D, Hamazaki T, Chang LJ, Yang LJ, Terada N, Jin S. Direct reprogramming of fibroblasts to myocytes via bacterial injection of MyoD protein. Cell Reprogram 2013; 15:117-25. [PMID: 23438194 DOI: 10.1089/cell.2012.0058] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Forced exogenous gene expression has been well characterized as an effective method for directing both cellular differentiation and dedifferentiation. However, transgene expression is not amenable for therapeutic application due to potential insertional mutagenesis. Protein-based techniques provide a safe alternative, but current protein delivery methods are quite limited by labor-intensive purification processes, low protein yield, and inefficient intracellular targeting. Such limitations may be overcome by using a naturally occurring bacterial protein injection system, called the type III secretion system (T3SS), which injects bacterial proteins directly into the eukaryotic cell cytoplasm. Using a genetically attenuated strain of Pseudomonas aeruginosa, we have previously described the ability of this system to easily deliver a high quantity of protein to both differentiated and pluripotent cells. MyoD is a key muscle regulatory factor, the overexpression of which is able to induce transdifferentiation of numerous cell types into functional myocytes. Here we demonstrate transient injection of MyoD protein by P. aeruginosa to be sufficient to induce myogenic conversion of mouse embryonic fibroblasts. In addition to clear morphological changes, muscle-specific gene expression has been observed both at mRNA and protein levels. These studies serve as a foundation for the bacterial delivery of transcription factors to efficiently modulate concentration-dependent and temporal activation of gene expression that directs cell fate without jeopardizing genomic integrity.
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Affiliation(s)
- Candace Bichsel
- Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL 32610, USA
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13
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Kim CH, Kim KH, Yoo YM. Melatonin-induced autophagy is associated with degradation of MyoD protein in C2C12 myoblast cells. J Pineal Res 2012; 53:289-97. [PMID: 22582971 DOI: 10.1111/j.1600-079x.2012.00998.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
MyoD is a muscle-specific transcriptional factor that acts as a master switch for skeletal muscle differentiation. This protein regulates myoblast proliferation and myogenic differentiation and is also a short-lived regulatory protein that is degraded by the ubiquitin system. However, the lysosomal pathway of MyoD protein degradation remains unknown. In this study, we sought to determine whether melatonin (1, 2mm)-induced autophagy causes the degradation of MyoD protein in C2C12 myoblast cells. Melatonin induced a significant increase in expression of the microtubule-associated protein 1 light chain 3 (LC3)-II and Beclin-1 proteins in a dose-dependent manner. Melatonin treatment also significantly increased p-ERK, Ras, and p-Akt expressions in a dose-dependent manner. However, Bax expression was high compared with the absence of melatonin treatment, and Bcl-2 expression was high in the 0.1-0.5mm melatonin treatments and low in the 1 and 2mm melatonin treatments. Under the same conditions, cytosolic MyoD protein was significantly decreased in a dose-dependent manner and completely eliminated by 36hr. This decrease in MyoD protein involved ubiquitin-mediated proteasomal activity with proteasome inhibitor MG132 or autophagy-dependent lysosomal degradation with lysosomal inhibitor bafilomycin A1 (Baf-A1). In the same condition, phosphorylation of the mammalian target of rapamycin, p-mTOR, and p-S6K expression with Baf-A1 or Baf-A1-plus melatonin treatment were significantly decreased compared with the levels after treatment with melatonin only. Together, these results suggest that melatonin (1, 2mm)-induced autophagy results in partial lysosomal degradation of MyoD protein in C2C12 myoblast cells.
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Affiliation(s)
- Chi Hyun Kim
- Department of Biomedical Engineering, College of Health Science, Yonsei University, Wonju, Gangwon-do, Korea
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14
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Cajee UF, Hull R, Ntwasa M. Modification by ubiquitin-like proteins: significance in apoptosis and autophagy pathways. Int J Mol Sci 2012; 13:11804-11831. [PMID: 23109884 PMCID: PMC3472776 DOI: 10.3390/ijms130911804] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Revised: 09/11/2012] [Accepted: 09/13/2012] [Indexed: 01/31/2023] Open
Abstract
Ubiquitin-like proteins (Ubls) confer diverse functions on their target proteins. The modified proteins are involved in various biological processes, including DNA replication, signal transduction, cell cycle control, embryogenesis, cytoskeletal regulation, metabolism, stress response, homeostasis and mRNA processing. Modifiers such as SUMO, ATG12, ISG15, FAT10, URM1, and UFM have been shown to modify proteins thus conferring functions related to programmed cell death, autophagy and regulation of the immune system. Putative modifiers such as Domain With No Name (DWNN) have been identified in recent times but not fully characterized. In this review, we focus on cellular processes involving human Ubls and their targets. We review current progress in targeting these modifiers for drug design strategies.
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Affiliation(s)
- Umar-Faruq Cajee
- School of Molecular & Cell Biology, Gatehouse 512, University of the Witwatersrand, Johannesburg, 2050, South Africa; E-Mails: (U.-F.C.); (R.H.)
| | - Rodney Hull
- School of Molecular & Cell Biology, Gatehouse 512, University of the Witwatersrand, Johannesburg, 2050, South Africa; E-Mails: (U.-F.C.); (R.H.)
| | - Monde Ntwasa
- School of Molecular & Cell Biology, Gatehouse 512, University of the Witwatersrand, Johannesburg, 2050, South Africa; E-Mails: (U.-F.C.); (R.H.)
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Noy T, Suad O, Taglicht D, Ciechanover A. HUWE1 ubiquitinates MyoD and targets it for proteasomal degradation. Biochem Biophys Res Commun 2012; 418:408-13. [PMID: 22277673 DOI: 10.1016/j.bbrc.2012.01.045] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2012] [Accepted: 01/07/2012] [Indexed: 11/26/2022]
Abstract
MyoD is a tissue-specific transcriptional activator that acts as a master switch for muscle development. It activates a broad array of muscle-specific genes, which leads to conversion of proliferating myoblasts into mature myotubes. The ubiquitin proteasome system (UPS) plays an important role in controlling MyoD. Both its N-terminal residue and internal lysines can be targeted by ubiquitin, and both modifications appear to direct it for proteasomal degradation. The protein is short-lived and has a half-life of ∼45min in different cells. It was reported that MyoD can be ubiquitinated by MAFbx/AT-1, but accumulating lines of experimental evidence showed that other ligase(s) may also participate in its targeting. Here we describe the involvement of HUWE1 in the ubiquitination and proteasomal degradation of MyoD. Furthermore, we show that the ligase can ubiquitinate the protein in its N-terminal residue.
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Affiliation(s)
- Tahel Noy
- 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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16
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Busso CS, Wedgeworth CM, Izumi T. Ubiquitination of human AP-endonuclease 1 (APE1) enhanced by T233E substitution and by CDK5. Nucleic Acids Res 2011; 39:8017-28. [PMID: 21727086 PMCID: PMC3185409 DOI: 10.1093/nar/gkr401] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Apurinic/apyrimidinic endonuclease-1 (APE1) is a multifunctional DNA repair/gene regulatory protein in mammalian cells, and was recently reported to be phosphorylated at Thr233 by CDK5. We here report that ubiquitination of T233E APE1, a mimicry of phospho-T233 APE1, was markedly increased in multiple cell lines. Expression of CDK5 enhanced monoubiquitination of endogenous APE1. Polyubiquitinated APE1 was decreased when K48R ubiquitin was expressed, suggesting that polyubiquitination was mediated mainly through Lys48 of ubiquitin. The ubiquitination activity of MDM2, consistent in its role for APE1 ubiquitination, was increased for T233E APE1 compared to the wild-type APE1. In mouse embryonic fibroblasts lacking the MDM2 gene, ubiquitination of T233E APE1 was still observed probably because of the decreased degradation activity for monoubiquitinated APE1 and because of backup E3 ligases in the cells. Monoubiquitinated APE1 was present in the nucleus, and analyzing global gene expression profiles with or without induction of a ubiquitin-APE1 fusion gene suggested that monoubiquitination enhanced the gene suppression activity of APE1. These data reveal a delicate balance of ubiquitination and phosphorylation activities that alter the gene regulatory function of APE1.
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Affiliation(s)
- Carlos S Busso
- Department of Otolaryngology, Stanley S. Scott Cancer Center, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA
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17
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Ziv I, Matiuhin Y, Kirkpatrick DS, Erpapazoglou Z, Leon S, Pantazopoulou M, Kim W, Gygi SP, Haguenauer-Tsapis R, Reis N, Glickman MH, Kleifeld O. A perturbed ubiquitin landscape distinguishes between ubiquitin in trafficking and in proteolysis. Mol Cell Proteomics 2011; 10:M111.009753. [PMID: 21427232 PMCID: PMC3098606 DOI: 10.1074/mcp.m111.009753] [Citation(s) in RCA: 108] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Any of seven lysine residues on ubiquitin can serve as the base for chain-extension, resulting in a sizeable spectrum of ubiquitin modifications differing in chain length or linkage type. By optimizing a procedure for rapid lysis, we charted the profile of conjugated cellular ubiquitin directly from whole cell extract. Roughly half of conjugated ubiquitin (even at high molecular weights) was nonextended, consisting of monoubiquitin modifications and chain terminators (endcaps). Of extended ubiquitin, the primary linkages were via Lys48 and Lys63. All other linkages were detected, contributing a relatively small portion that increased at lower molecular weights. In vivo expression of lysineless ubiquitin (K0 Ub) perturbed the ubiquitin landscape leading to elevated levels of conjugated ubiquitin, with a higher mono-to-poly ratio. Affinity purification of these trapped conjugates identified a comprehensive list of close to 900 proteins including novel targets. Many of the proteins enriched by K0 ubiquitination were membrane-associated, or involved in cellular trafficking. Prime among them are components of the ESCRT machinery and adaptors of the Rsp5 E3 ubiquitin ligase. Ubiquitin chains associated with these substrates were enriched for Lys63 linkages over Lys48, indicating that K0 Ub is unevenly distributed throughout the ubiquitinome. Biological assays validated the interference of K0 Ub with protein trafficking and MVB sorting, minimally affecting Lys48-dependent turnover of proteasome substrates. We conclude that despite the shared use of the ubiquitin molecule, the two branches of the ubiquitin machinery—the ubiquitin-proteasome system and the ubiquitin trafficking system—were unevenly perturbed by expression of K0 ubiquitin.
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Affiliation(s)
- Inbal Ziv
- Department of Biology, Technion Israel institute of Technology, Haifa 32000, Israel
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18
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Lung J, Liu KJ, Chang JY, Leu SJ, Shih NY. MBP-1 is efficiently encoded by an alternative transcript of the ENO1 gene but post-translationally regulated by proteasome-dependent protein turnover. FEBS J 2010; 277:4308-21. [PMID: 20849415 DOI: 10.1111/j.1742-4658.2010.07819.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The c-myc promoter-binding protein-1 (MBP-1) is a transcriptional suppressor of tumorigenesis and thought to be the product of alternative translation initiation of the α-enolase (ENO1) transcript. In the present study, we cloned a 2552-bp novel cDNA with a putative coding sequence of MBP-1 and functionally examined its ability to encode the MBP-1 protein. Similarly to ENO1, the obtained MBP-1 was widely and differentially expressed in a variety of normal tissues and cancer cells. Experiments using MBP-1 promoter-driven luciferase reporter assays, biochemical cell fractionation followed by RT-PCR detection of the cytoplasmic mRNA, and transcription/translation-coupled reactions, consistently demonstrated that this novel transcript was alternatively transcribed from intron III of the ENO1 gene and was feasible for MBP-1 production. Hypoxia treatments significantly increased the transcriptional activation of the MBP-1 gene. Blocking the proteasomal degradation by MG132 stabilized the MBP-1 protein in cells. Compared with the translation efficiency for production of the MBP-1 protein, the MBP-1 transcript was 17.8 times more efficient than the ENO1 transcript. Thus, we suggest that this newly discovered transcript is a genuine template for the protein synthesis of MBP-1 in cells, and optimal expression of this gene in tumors may lead to effective clinical therapies for cancers.
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Affiliation(s)
- Jrhau Lung
- National Institute of Cancer Research, National Health Research Institutes, Tainan, Taiwan
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Abstract
The host innate immune response, including the production of type-I IFN, represents the primary line of defense against invading viral pathogens. Of the hundreds of IFN-stimulated genes (ISGs) discovered to date, ISG15 was one of the first identified and shown to encode a ubiquitin-like protein that functions, in part, as a modifier of protein function. Evidence implicating ISG15 as an innate immune protein with broad-spectrum antiviral activity continues to accumulate rapidly. This review will summarize recent findings on the innate antiviral activity of ISG15, with a focus on the interplay between ubiquitination and ISGylation pathways resulting in modulation of RNA virus assembly/budding. Indeed, ubiquitination is known to be proviral for some RNA viruses, whereas the parallel ISGylation pathway is known to be antiviral. A better understanding of the antiviral activities of ISG15 will enhance our fundamental knowledge of host innate responses to viral pathogens and may provide insight useful for the development of novel therapeutic approaches designed to enhance the immune response against such pathogens.
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Affiliation(s)
- Ronald N Harty
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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20
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Lehman NL. The ubiquitin proteasome system in neuropathology. Acta Neuropathol 2009; 118:329-47. [PMID: 19597829 PMCID: PMC2716447 DOI: 10.1007/s00401-009-0560-x] [Citation(s) in RCA: 145] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2009] [Revised: 06/10/2009] [Accepted: 06/11/2009] [Indexed: 11/29/2022]
Abstract
The ubiquitin proteasome system (UPS) orchestrates the turnover of innumerable cellular proteins. In the process of ubiquitination the small protein ubiquitin is attached to a target protein by a peptide bond. The ubiquitinated target protein is subsequently shuttled to a protease complex known as the 26S proteasome and subjected to degradative proteolysis. The UPS facilitates the turnover of proteins in several settings. It targets oxidized, mutant or misfolded proteins for general proteolytic destruction, and allows for the tightly controlled and specific destruction of proteins involved in development and differentiation, cell cycle progression, circadian rhythms, apoptosis, and other biological processes. In neuropathology, alteration of the UPS, or mutations in UPS target proteins may result in signaling abnormalities leading to the initiation or progression of tumors such as astrocytomas, hemangioblastomas, craniopharyngiomas, pituitary adenomas, and medulloblastomas. Dysregulation of the UPS may also contribute to tumor progression by perturbation of DNA replication and mitotic control mechanisms, leading to genomic instability. In neurodegenerative diseases caused by the expression of mutant proteins, the cellular accumulation of these proteins may overload the UPS, indirectly contributing to the disease process, e.g., sporadic Parkinsonism and prion diseases. In other cases, mutation of UPS components may directly cause pathological accumulation of proteins, e.g., autosomal recessive Parkinsonism and spinocerebellar ataxias. Defects or dysfunction of the UPS may also underlie cognitive disorders such as Angelman syndrome, Rett syndrome and autism, and muscle and nerve diseases, e.g., inclusion body myopathy and giant axon neuropathy. This paper describes the basic biochemical mechanisms comprising the UPS and reviews both its theoretical and proven involvement in neuropathological diseases. The potential for the UPS as a target of pharmacological therapy is also discussed.
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Affiliation(s)
- Norman L Lehman
- Department of Pathology and Laboratory Medicine, Hermelin Brain Tumor Center, Henry Ford Health System, Detroit, MI 48202, USA.
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21
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Kravtsova-Ivantsiv Y, Cohen S, Ciechanover A. Modification by single ubiquitin moieties rather than polyubiquitination is sufficient for proteasomal processing of the p105 NF-kappaB precursor. Mol Cell 2009; 33:496-504. [PMID: 19250910 DOI: 10.1016/j.molcel.2009.01.023] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2008] [Revised: 12/25/2008] [Accepted: 01/08/2009] [Indexed: 10/21/2022]
Abstract
Activation of NF-kappaB is regulated via numerous ubiquitin- and proteasome-mediated steps; an important one is processing of the precursor p105 to the p50 active subunit. The mechanisms involved are largely unknown, because this is an exceptional case where the ubiquitin system does not destroy its substrate completely. Here, we demonstrate that proteasomal processing of p105 requires ubiquitin but not generation of polyubiquitin chains. In vitro, ubiquitin species that cannot polymerize mediate processing. In yeasts that express nonpolymerizable ubiquitins, processing proceeds normally, whereas degradation of substrates that are dependent on polyubiquitination is inhibited. Similar results were obtained in mammalian cells. Interestingly, processing requires multiple monoubiquitinations, because progressive elimination of lysines in p105 is accompanied by gradual inhibition of p50 generation. Finally, the proteasome recognizes the multiply monoubiquitinated p105. These findings suggest that a proteolytic signal can be composed of a cluster of single ubiquitins, not necessarily a chain.
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Affiliation(s)
- Yelena Kravtsova-Ivantsiv
- Cancer and Vascular Biology Center, The Rappaport Faculty of Medicine and Research Institute, Technion-Israel Institute of Technology, Haifa 31096, Israel
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22
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Vosper JMD, McDowell GS, Hindley CJ, Fiore-Heriche CS, Kucerova R, Horan I, Philpott A. Ubiquitylation on canonical and non-canonical sites targets the transcription factor neurogenin for ubiquitin-mediated proteolysis. J Biol Chem 2009; 284:15458-68. [PMID: 19336407 DOI: 10.1074/jbc.m809366200] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Polyubiquitylation targets multiple proteins for degradation by the proteasome. Typically, the first ubiquitin is linked to lysine residues in the substrate for degradation via an isopeptide bond, although rarely ubiquitin linkage to the N-terminal residue has also been observed. We have recently shown that Neurogenin (NGN), a basic helix-loop-helix transcription factor that plays a central role in regulating neuronal differentiation, is degraded by ubiquitin-mediated proteolysis. We have taken a biochemical and mutagenesis approach to investigate sites of ubiquitylation of NGN, initially using extracts of eggs from the frog Xenopus laevis as a source of ubiquitylation and degradation components. NGN can be targeted for destruction by ubiquitylation via lysines or the N terminus. However, we see that a modified NGN, where canonical lysine ubiquitylation and N-terminally linked ubiquitylation are prevented, is nevertheless ubiquitylated and degraded by the proteasome. We show that polyubiquitin chains covalently attach to non-canonical cysteine residues in NGN, and these non-canonical linkages alone are capable of targeting NGN protein for destruction. Importantly, canonical and non-canonical ubiquitylation occurs simultaneously in the native protein and may differ in importance for driving degradation in interphase and mitosis. We conclude that native NGN is ubiquitylated on multiple canonical and non-canonical sites by cellular ubiquitin ligases, and all types of linkage can contribute to protein turnover.
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Affiliation(s)
- Jonathan M D Vosper
- Department of Oncology, University of Cambridge, Hutchison/Medical Research Council (MRC) Research Centre, Addenbrooke's Hospital, Cambridge CB2 0XZ, United Kingdom
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