51
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French ME, Klosowiak JL, Aslanian A, Reed SI, Yates JR, Hunter T. Mechanism of ubiquitin chain synthesis employed by a HECT domain ubiquitin ligase. J Biol Chem 2017; 292:10398-10413. [PMID: 28461335 DOI: 10.1074/jbc.m117.789479] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2017] [Revised: 04/27/2017] [Indexed: 11/06/2022] Open
Abstract
Homologous to E6AP C-terminal (HECT) ubiquitin (Ub) ligases (E3s) are a large class of enzymes that bind to their substrates and catalyze ubiquitination through the formation of a Ub thioester intermediate. The mechanisms by which these E3s assemble polyubiquitin chains on their substrates remain poorly defined. We report here that the Nedd4 family HECT E3, WWP1, assembles substrate-linked Ub chains containing Lys-63, Lys-48, and Lys-11 linkages (Lys-63 > Lys-48 > Lys-11). Our results demonstrate that WWP1 catalyzes the formation of Ub chains through a sequential addition mechanism, in which Ub monomers are transferred in a successive fashion to the substrate, and that ubiquitination by WWP1 requires the presence of a low-affinity, noncovalent Ub-binding site within the HECT domain. Unexpectedly, we find that the formation of Ub chains by WWP1 occurs in two distinct phases. In the first phase, chains are synthesized in a unidirectional manner and are linked exclusively through Lys-63 of Ub. In the second phase, chains are elongated in a multidirectional fashion characterized by the formation of mixed Ub linkages and branched structures. Our results provide new insight into the mechanism of Ub chain formation employed by Nedd4 family HECT E3s and suggest a framework for understanding how this family of E3s generates Ub signals that function in proteasome-independent and proteasome-dependent pathways.
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Affiliation(s)
- Michael E French
- From the Molecular and Cell Biology Laboratory, Salk Institute for Biological Studies, La Jolla, California 92037.,the Departments of Cell and Molecular Biology and
| | - Julian L Klosowiak
- the Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611
| | - Aaron Aslanian
- From the Molecular and Cell Biology Laboratory, Salk Institute for Biological Studies, La Jolla, California 92037.,Chemical Physiology, The Scripps Research Institute, La Jolla, California 92037, and
| | | | - John R Yates
- Chemical Physiology, The Scripps Research Institute, La Jolla, California 92037, and
| | - Tony Hunter
- From the Molecular and Cell Biology Laboratory, Salk Institute for Biological Studies, La Jolla, California 92037,
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52
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Crowe SO, Rana ASJB, Deol KK, Ge Y, Strieter ER. Ubiquitin Chain Enrichment Middle-Down Mass Spectrometry Enables Characterization of Branched Ubiquitin Chains in Cellulo. Anal Chem 2017; 89:4428-4434. [PMID: 28291339 PMCID: PMC5541364 DOI: 10.1021/acs.analchem.6b03675] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Ubiquitin (Ub) has a broad functional range that has been ascribed to the formation of an array of polymeric ubiquitin chains. Understanding the precise roles of ubiquitin chains, however, is difficult due to their complex chain topologies. Branched ubiquitin chains are particularly challenging, as multiple modifications on a single ubiquitin preclude the use of standard bottom-up proteomic approaches. Developing methods to overcome these challenges is crucial considering evidence suggesting branched chains regulate the stability of proteins. In this study, we employ Ubiquitin Chain Enrichment Middle-down Mass Spectrometry (UbiChEM-MS) to identify branched chains that cannot be detected using bottom-up proteomic methods. Specifically, we employ tandem ubiquitin binding entities (TUBEs) and the K29-selective Npl4 Zinc Finger 1 (NZF1) domain from the deubiquitinase TRABID to enrich for chains from human cells. Minimal trypsinolysis followed by high resolution mass spectrometric analysis reveals that Ub chain branching can indeed be detected using both Ub binding domains (UBDs) tested at endogenous levels. We find that ∼1% of chains isolated with TUBEs contain Ub branch points, with this value rising to ∼4% after proteasome inhibition. Electron-transfer dissociation (ETD) analysis indicates the presence of K48 in these branched chains. The use of the NZF1 domain reveals that ∼4% of the isolated chains contain branch points with no apparent dependence on proteasome inhibition. Our results demonstrate an effective strategy for detecting and characterizing the dynamics of branched conjugates under different cellular conditions.
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Affiliation(s)
- Sean O. Crowe
- Department of Chemistry, University of Massachusetts-Amherst, Amherst, Massachusetts 01003, United States
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Ambar S. J. B. Rana
- Department of Chemistry, University of Massachusetts-Amherst, Amherst, Massachusetts 01003, United States
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Kirandeep K. Deol
- Department of Chemistry, University of Massachusetts-Amherst, Amherst, Massachusetts 01003, United States
| | - Ying Ge
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
- Department of Cell and Regenerative Biology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
- Human Proteomics Program, University of Wisconsin-Madison, Madison, Wisconsin 53705, United States
| | - Eric R. Strieter
- Department of Chemistry, University of Massachusetts-Amherst, Amherst, Massachusetts 01003, United States
- Department of Biochemistry and Molecular Biology, University of Massachusetts-Amherst, Amherst, Massachusetts 01003, United States
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53
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Ho HC, MacGurn JA, Emr SD. Deubiquitinating enzymes Ubp2 and Ubp15 regulate endocytosis by limiting ubiquitination and degradation of ARTs. Mol Biol Cell 2017; 28:1271-1283. [PMID: 28298493 PMCID: PMC5415021 DOI: 10.1091/mbc.e17-01-0008] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 02/27/2017] [Accepted: 02/28/2017] [Indexed: 12/18/2022] Open
Abstract
Endocytic down-regulation of cell-surface proteins is a fundamental cellular process for cell survival and adaptation to environmental stimuli. Ubiquitination of cargo proteins serves as the sorting signal for downstream trafficking and relies on the arrestin-related trafficking adaptor (ART)-Rsp5 ubiquitin ligase adaptor network in yeast. Hence proper regulation of the abundance and activity of these ligase-adaptor complexes is critical for main-tenance of optimal plasma membrane protein composition. Here we report that the stability of ARTs is regulated by the deubiquitinating enzymes (DUBs) Ubp2 and Ubp15. By counteracting the E3 ubiquitin ligase Rsp5, Ubp2 and Ubp15 prevent hyperubiquitination and proteasomal degradation of ARTs. Specifically, we show that loss of both Ubp2 and Ubp15 results in a defect in Hxt6 endocytosis associated with Art4 instability. Our results uncover a novel function for DUBs in the endocytic pathway by which Ubp2 and Ubp15 positively regulate the ART-Rsp5 network.
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Affiliation(s)
- Hsuan-Chung Ho
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853
| | - Jason A MacGurn
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37240
| | - Scott D Emr
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853
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54
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Abstract
The ubiquitin proteasome system controls the concentrations of regulatory proteins and removes damaged and misfolded proteins from cells. Proteins are targeted to the protease at the center of this system, the proteasome, by ubiquitin tags, but ubiquitin is also used as a signal in other cellular processes. Specificity is conferred by the size and structure of the ubiquitin tags, which are recognized by receptors associated with the different cellular processes. However, the ubiquitin code remains ambiguous, and the same ubiquitin tag can target different proteins to different fates. After binding substrate protein at the ubiquitin tag, the proteasome initiates degradation at a disordered region in the substrate. The proteasome has pronounced preferences for the initiation site, and its recognition represents a second component of the degradation signal.
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Affiliation(s)
- Houqing Yu
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas 78712;
| | - Andreas Matouschek
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas 78712;
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55
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Zhang X, Smits AH, van Tilburg GBA, Jansen PWTC, Makowski MM, Ovaa H, Vermeulen M. An Interaction Landscape of Ubiquitin Signaling. Mol Cell 2017; 65:941-955.e8. [PMID: 28190767 DOI: 10.1016/j.molcel.2017.01.004] [Citation(s) in RCA: 83] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 12/06/2016] [Accepted: 01/05/2017] [Indexed: 02/07/2023]
Abstract
Intracellular signaling via the covalent attachment of different ubiquitin linkages to protein substrates is fundamental to many cellular processes. Although linkage-selective ubiquitin interactors have been studied on a case-by-case basis, proteome-wide analyses have not been conducted yet. Here, we present ubiquitin interactor affinity enrichment-mass spectrometry (UbIA-MS), a quantitative interaction proteomics method that makes use of chemically synthesized diubiquitin to enrich and identify ubiquitin linkage interactors from crude cell lysates. UbIA-MS reveals linkage-selective diubiquitin interactions in multiple cell types. For example, we identify TAB2 and TAB3 as novel K6 diubiquitin interactors and characterize UCHL3 as a K27-linkage selective interactor that regulates K27 polyubiquitin chain formation in cells. Additionally, we show a class of monoubiquitin and K6 diubiquitin interactors whose binding is induced by DNA damage. We expect that our proteome-wide diubiquitin interaction landscape and established workflows will have broad applications in the ongoing efforts to decipher the complex language of ubiquitin signaling.
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Affiliation(s)
- Xiaofei Zhang
- Department of Molecular Biology, Faculty of Science, Radboud Institute for Molecular Life Sciences, Radboud University Nijmegen, Nijmegen 6525, the Netherlands.
| | - Arne H Smits
- Department of Molecular Biology, Faculty of Science, Radboud Institute for Molecular Life Sciences, Radboud University Nijmegen, Nijmegen 6525, the Netherlands
| | - Gabrielle B A van Tilburg
- Division of Cell Biology II, Netherlands Cancer Institute, Plesmanlaan 121, Amsterdam 1066CX, the Netherlands; Department of Chemical Immunology, Leiden University Medical Center, Albinusdreef 2, Leiden 2333ZA, the Netherlands
| | - Pascal W T C Jansen
- Department of Molecular Biology, Faculty of Science, Radboud Institute for Molecular Life Sciences, Radboud University Nijmegen, Nijmegen 6525, the Netherlands
| | - Matthew M Makowski
- Department of Molecular Biology, Faculty of Science, Radboud Institute for Molecular Life Sciences, Radboud University Nijmegen, Nijmegen 6525, the Netherlands
| | - Huib Ovaa
- Division of Cell Biology II, Netherlands Cancer Institute, Plesmanlaan 121, Amsterdam 1066CX, the Netherlands; Department of Chemical Immunology, Leiden University Medical Center, Albinusdreef 2, Leiden 2333ZA, the Netherlands.
| | - Michiel Vermeulen
- Department of Molecular Biology, Faculty of Science, Radboud Institute for Molecular Life Sciences, Radboud University Nijmegen, Nijmegen 6525, the Netherlands.
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56
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Brown NG, VanderLinden R, Watson ER, Weissmann F, Ordureau A, Wu KP, Zhang W, Yu S, Mercredi PY, Harrison JS, Davidson IF, Qiao R, Lu Y, Dube P, Brunner MR, Grace CRR, Miller DJ, Haselbach D, Jarvis MA, Yamaguchi M, Yanishevski D, Petzold G, Sidhu SS, Kuhlman B, Kirschner MW, Harper JW, Peters JM, Stark H, Schulman BA. Dual RING E3 Architectures Regulate Multiubiquitination and Ubiquitin Chain Elongation by APC/C. Cell 2016; 165:1440-1453. [PMID: 27259151 DOI: 10.1016/j.cell.2016.05.037] [Citation(s) in RCA: 113] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Revised: 04/16/2016] [Accepted: 05/09/2016] [Indexed: 11/25/2022]
Abstract
Protein ubiquitination involves E1, E2, and E3 trienzyme cascades. E2 and RING E3 enzymes often collaborate to first prime a substrate with a single ubiquitin (UB) and then achieve different forms of polyubiquitination: multiubiquitination of several sites and elongation of linkage-specific UB chains. Here, cryo-EM and biochemistry show that the human E3 anaphase-promoting complex/cyclosome (APC/C) and its two partner E2s, UBE2C (aka UBCH10) and UBE2S, adopt specialized catalytic architectures for these two distinct forms of polyubiquitination. The APC/C RING constrains UBE2C proximal to a substrate and simultaneously binds a substrate-linked UB to drive processive multiubiquitination. Alternatively, during UB chain elongation, the RING does not bind UBE2S but rather lures an evolving substrate-linked UB to UBE2S positioned through a cullin interaction to generate a Lys11-linked chain. Our findings define mechanisms of APC/C regulation, and establish principles by which specialized E3-E2-substrate-UB architectures control different forms of polyubiquitination.
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Affiliation(s)
- Nicholas G Brown
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Ryan VanderLinden
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA; Howard Hughes Medical Institute, Memphis, TN 38105, USA
| | - Edmond R Watson
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Florian Weissmann
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), 1030 Vienna, Austria
| | - Alban Ordureau
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Kuen-Phon Wu
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Wei Zhang
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, Ontario M5S3E1, Canada
| | - Shanshan Yu
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Peter Y Mercredi
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Joseph S Harrison
- Department of Biochemistry and Biophysics and Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, North Carolina 27599, USA
| | - Iain F Davidson
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), 1030 Vienna, Austria
| | - Renping Qiao
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), 1030 Vienna, Austria
| | - Ying Lu
- Department of Systems Biology, Harvard Medical School, Boston, MA, 02115, USA
| | - Prakash Dube
- Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Michael R Brunner
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Christy R R Grace
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Darcie J Miller
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - David Haselbach
- Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Marc A Jarvis
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), 1030 Vienna, Austria
| | - Masaya Yamaguchi
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - David Yanishevski
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Georg Petzold
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), 1030 Vienna, Austria
| | - Sachdev S Sidhu
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, Ontario M5S3E1, Canada
| | - Brian Kuhlman
- Department of Biochemistry and Biophysics and Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, North Carolina 27599, USA
| | - Marc W Kirschner
- Department of Systems Biology, Harvard Medical School, Boston, MA, 02115, USA
| | - J Wade Harper
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Jan-Michael Peters
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), 1030 Vienna, Austria.
| | - Holger Stark
- Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany.
| | - Brenda A Schulman
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA; Howard Hughes Medical Institute, Memphis, TN 38105, USA.
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57
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Abstract
Protein complexes form the critical foundation for a wide range of biological process, however understanding the intricate details of their activities is often challenging. In this review we describe how mass spectrometry plays a key role in the analysis of protein assemblies and the cellular pathways which they are involved in. Specifically, we discuss how the versatility of mass spectrometric approaches provides unprecedented information on multiple levels. We demonstrate this on the ubiquitin-proteasome proteolytic pathway, a process that is responsible for protein turnover. We follow the various steps of this degradation route and illustrate the different mass spectrometry workflows that were applied for elucidating molecular information. Overall, this review aims to stimulate the integrated use of multiple mass spectrometry approaches for analyzing complex biological systems.
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58
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Grice GL, Nathan JA. The recognition of ubiquitinated proteins by the proteasome. Cell Mol Life Sci 2016; 73:3497-506. [PMID: 27137187 PMCID: PMC4980412 DOI: 10.1007/s00018-016-2255-5] [Citation(s) in RCA: 218] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 04/22/2016] [Accepted: 04/26/2016] [Indexed: 12/14/2022]
Abstract
The ability of ubiquitin to form up to eight different polyubiquitin chain linkages generates complexity within the ubiquitin proteasome system, and accounts for the diverse roles of ubiquitination within the cell. Understanding how each type of ubiquitin linkage is correctly interpreted by ubiquitin binding proteins provides important insights into the link between chain recognition and cellular fate. A major function of ubiquitination is to signal degradation of intracellular proteins by the 26S proteasome. Lysine-48 (K48) linked polyubiquitin chains are well established as the canonical signal for proteasomal degradation, but recent studies show a role for other ubiquitin linked chains in facilitating degradation by the 26S proteasome. Here, we review how different types of polyubiquitin linkage bind to ubiquitin receptors on the 26S proteasome, how they signal degradation and discuss the implications of ubiquitin chain linkage in regulating protein breakdown by the proteasome.
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Affiliation(s)
- Guinevere L Grice
- Department of Medicine, Cambridge Institute for Medical Research, University of Cambridge, Cambridge, CB2 0XY, UK
| | - James A Nathan
- Department of Medicine, Cambridge Institute for Medical Research, University of Cambridge, Cambridge, CB2 0XY, UK.
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59
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The Ubiquitination of NF-κB Subunits in the Control of Transcription. Cells 2016; 5:cells5020023. [PMID: 27187478 PMCID: PMC4931672 DOI: 10.3390/cells5020023] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Revised: 05/03/2016] [Accepted: 05/06/2016] [Indexed: 02/06/2023] Open
Abstract
Nuclear factor (NF)-κB has evolved as a latent, inducible family of transcription factors fundamental in the control of the inflammatory response. The transcription of hundreds of genes involved in inflammation and immune homeostasis require NF-κB, necessitating the need for its strict control. The inducible ubiquitination and proteasomal degradation of the cytoplasmic inhibitor of κB (IκB) proteins promotes the nuclear translocation and transcriptional activity of NF-κB. More recently, an additional role for ubiquitination in the regulation of NF-κB activity has been identified. In this case, the ubiquitination and degradation of the NF-κB subunits themselves plays a critical role in the termination of NF-κB activity and the associated transcriptional response. While there is still much to discover, a number of NF-κB ubiquitin ligases and deubiquitinases have now been identified which coordinate to regulate the NF-κB transcriptional response. This review will focus the regulation of NF-κB subunits by ubiquitination, the key regulatory components and their impact on NF-κB directed transcription.
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60
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Abstract
Protein ubiquitination is a dynamic multifaceted post-translational modification involved in nearly all aspects of eukaryotic biology. Once attached to a substrate, the 76-amino acid protein ubiquitin is subjected to further modifications, creating a multitude of distinct signals with distinct cellular outcomes, referred to as the 'ubiquitin code'. Ubiquitin can be ubiquitinated on seven lysine (Lys) residues or on the N-terminus, leading to polyubiquitin chains that can encompass complex topologies. Alternatively or in addition, ubiquitin Lys residues can be modified by ubiquitin-like molecules (such as SUMO or NEDD8). Finally, ubiquitin can also be acetylated on Lys, or phosphorylated on Ser, Thr or Tyr residues, and each modification has the potential to dramatically alter the signaling outcome. While the number of distinctly modified ubiquitin species in cells is mind-boggling, much progress has been made to characterize the roles of distinct ubiquitin modifications, and many enzymes and receptors have been identified that create, recognize or remove these ubiquitin modifications. We here provide an overview of the various ubiquitin modifications present in cells, and highlight recent progress on ubiquitin chain biology. We then discuss the recent findings in the field of ubiquitin acetylation and phosphorylation, with a focus on Ser65-phosphorylation and its role in mitophagy and Parkin activation.
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Affiliation(s)
- Kirby N Swatek
- Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - David Komander
- Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
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61
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Martinez-Fonts K, Matouschek A. A Rapid and Versatile Method for Generating Proteins with Defined Ubiquitin Chains. Biochemistry 2016; 55:1898-908. [PMID: 26943792 DOI: 10.1021/acs.biochem.5b01310] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Ubiquitin and polyubiquitin chains target proteins for a wide variety of cellular processes. Ubiquitin-mediated targeting is regulated by the lysine through which the ubiquitins are linked as well as the broader ubiquitin landscape on the protein. The mechanisms of this regulation are not fully understood. For example, the canonical proteasome targeting signal is a lysine 48-linked polyubiquitin chain, and the canonical endocytosis signal is a lysine 63-linked polyubiquitin chain. However, lysine 63-linked polyubiquitin chains can also target substrates for degradation. Biochemical studies of ubiquitinated proteins have been limited by the difficulty of building proteins with well-defined polyubiquitin chains. Here we describe an efficient and versatile method for synthesizing ubiquitin chains of defined linkage and length. The synthesized ubiquitin chains are then attached to any protein containing a ubiquitin moiety. These proteins can be used to study ubiquitin targeting in in vitro assays in the tightly controlled manner required for biochemical studies.
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Affiliation(s)
- Kirby Martinez-Fonts
- Department of Molecular Biosciences, The University of Texas at Austin , Austin, Texas 78712, United States.,Department of Molecular Biosciences, Northwestern University , Evanston, Illinois 60208, United States
| | - Andreas Matouschek
- Department of Molecular Biosciences, The University of Texas at Austin , Austin, Texas 78712, United States.,Department of Molecular Biosciences, Northwestern University , Evanston, Illinois 60208, United States
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62
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He F, Wollscheid HP, Nowicka U, Biancospino M, Valentini E, Ehlinger A, Acconcia F, Magistrati E, Polo S, Walters KJ. Myosin VI Contains a Compact Structural Motif that Binds to Ubiquitin Chains. Cell Rep 2016; 14:2683-94. [PMID: 26971995 DOI: 10.1016/j.celrep.2016.01.079] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Revised: 11/24/2015] [Accepted: 01/27/2016] [Indexed: 12/13/2022] Open
Abstract
Myosin VI is critical for cargo trafficking and sorting during early endocytosis and autophagosome maturation, and abnormalities in these processes are linked to cancers, neurodegeneration, deafness, and hypertropic cardiomyopathy. We identify a structured domain in myosin VI, myosin VI ubiquitin-binding domain (MyUb), that binds to ubiquitin chains, especially those linked via K63, K11, and K29. Herein, we solve the solution structure of MyUb and MyUb:K63-linked diubiquitin. MyUb folds as a compact helix-turn-helix-like motif and nestles between the ubiquitins of K63-linked diubiquitin, interacting with distinct surfaces of each. A nine-amino-acid extension at the C-terminal helix (Helix2) of MyUb is required for myosin VI interaction with endocytic and autophagic adaptors. Structure-guided mutations revealed that a functional MyUb is necessary for optineurin interaction. In addition, we found that an isoform-specific helix restricts MyUb binding to ubiquitin chains. This work provides fundamental insights into myosin VI interaction with ubiquitinated cargo and functional adaptors.
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Affiliation(s)
- Fahu He
- Protein Processing Section, Structural Biophysics Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA
| | - Hans-Peter Wollscheid
- IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Via Adamello 16, 20139 Milano, Italy
| | - Urszula Nowicka
- Protein Processing Section, Structural Biophysics Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA
| | - Matteo Biancospino
- IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Via Adamello 16, 20139 Milano, Italy
| | - Eleonora Valentini
- IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Via Adamello 16, 20139 Milano, Italy
| | - Aaron Ehlinger
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Filippo Acconcia
- IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Via Adamello 16, 20139 Milano, Italy
| | - Elisa Magistrati
- IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Via Adamello 16, 20139 Milano, Italy
| | - Simona Polo
- IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Via Adamello 16, 20139 Milano, Italy; DIPO, Dipartimento di Oncologia ed Emato-oncologia, Università degli Studi di Milano, Via di Rudinì 8, 20122 Milan, Italy.
| | - Kylie J Walters
- Protein Processing Section, Structural Biophysics Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA.
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63
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Alfano C, Faggiano S, Pastore A. The Ball and Chain of Polyubiquitin Structures. Trends Biochem Sci 2016; 41:371-385. [PMID: 26899455 DOI: 10.1016/j.tibs.2016.01.006] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Revised: 01/18/2016] [Accepted: 01/22/2016] [Indexed: 10/22/2022]
Abstract
Ubiquitylation is a post-translational modification implicated in several different cellular pathways. The possibility of forming chains through covalent crosslinking between any of the seven lysines, or the initial methionine, and the C terminus of another moiety provides ubiquitin (Ub) with special flexibility in its function in signalling. Here, we review the knowledge accumulated over the past several years about the functions and structural features of polyUb chains. This analysis reveals the need to understand further the functional role of some of the linkages and the structural code that determines recognition of polyUbs by protein partners.
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Affiliation(s)
- Caterina Alfano
- Department of Clinical and Basic Neuroscience, King's College London, London, UK
| | | | - Annalisa Pastore
- Department of Clinical and Basic Neuroscience, King's College London, London, UK.
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64
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Abstract
Ubiquitin plays an essential role in modulating protein functions, and deregulation of the ubiquitin system leads to the development of multiple human diseases. Owing to its molecular features, ubiquitin can form various homo- and heterotypic polymers on substrate proteins, thereby provoking distinct cellular responses. The concept of multifaceted ubiquitin chains encoding different functions has been substantiated in recent years. It has been established that all possible ubiquitin linkage types are utilized for chain assembly and propagation of specific signals in vivo. In addition, branched ubiquitin chains and phosphorylated ubiquitin molecules have been put under the spotlight recently. The development of novel technologies has provided detailed insights into the structure and function of previously poorly understood ubiquitin signals. In this Cell Science at a Glance article and accompanying poster, we provide an update on the complexity of ubiquitin chains and their physiological relevance.
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Affiliation(s)
- Masato Akutsu
- Buchmann Institute for Molecular Life Sciences, Institute of Biochemistry II, Goethe University, Max-von Laue-Str. 15, Frankfurt 60438, Germany
| | - Ivan Dikic
- Buchmann Institute for Molecular Life Sciences, Institute of Biochemistry II, Goethe University, Max-von Laue-Str. 15, Frankfurt 60438, Germany
| | - Anja Bremm
- Buchmann Institute for Molecular Life Sciences, Institute of Biochemistry II, Goethe University, Max-von Laue-Str. 15, Frankfurt 60438, Germany
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