1
|
Yang X, Yan K, Zhan Q, Chen H, Pei CZ, Zhu L. Exploration of Diagnostic Deubiquitinating Enzymes in Endometriosis and Its Immune Infiltration. Biochem Genet 2024; 62:4359-4379. [PMID: 38302849 DOI: 10.1007/s10528-023-10653-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 12/27/2023] [Indexed: 02/03/2024]
Abstract
The mechanism involved in the pathogenesis of endometriosis is poorly understood. The purpose of this study is to identify key deubiquitinating enzymes (DUBs) for endometriosis diagnosis and elucidate the possible mechanism, offering novel insights for noninvasive early diagnosis and treatment. Four gene expression datasets were employed from the Gene Expression Omnibus to identify differentially expressed genes (DEGs) between endometriosis and normal controls. GO and KEGG pathways were performed for enrichment analysis. Calibration curves, ROC, DCA, and clinical impact curves verified the clinical usefulness of the nomogram model. In addition, the ssGSEA method was conducted to estimate 23 types of immune cells. A specific DUB gene signature was constructed with Lasso regression, univariate logistic regression, and SVM analysis. RT-qPCR validated the expression of biomarkers. A total of 85 endometriosis-related DUBs were identified in the eutopic endometrium. Among them, 20 DUBs were found to be correlated with the severity of endometriosis. A diagnostic risk model based on five DUB-related genes (USP21, USP48, ZRANB1, COPS5, and EIF3F) was developed using lasso-cox regression analysis. The nomogram model exhibited a strong predictive ability to diagnose endometriosis. KEGG analysis revealed that ubiquitin-mediated proteolysis was activated in patients suffering from severe symptoms. Analysis of immune cell infiltration revealed a positive correlation between USP21 and multiple immune cells in the eutopic endometrium. However, EIF3F showed an opposite relationship. Dysregulation of DUBs was related to the immune microenvironment in endometriosis. Results from RT-qPCR confirmed the expression of DEGs in clinical samples. In summary, the diagnostic model for endometriosis constructed using five differentially expressed DUB genes demonstrates strong diagnostic capability, suggesting that these genes could serve as potential candidate biomarkers and therapeutic targets.
Collapse
Affiliation(s)
- Xinyun Yang
- Department of Reproductive Endocrinology, Zhejiang University School of Medicine, Women's Hospital, Hangzhou, Zhejiang, People's Republic of China
| | - Kai Yan
- Department of Reproductive Endocrinology, Zhejiang University School of Medicine, Women's Hospital, Hangzhou, Zhejiang, People's Republic of China
| | - Qitao Zhan
- Department of Reproductive Endocrinology, Zhejiang University School of Medicine, Women's Hospital, Hangzhou, Zhejiang, People's Republic of China
| | - Hao Chen
- Department of Pathology, Hangzhou Women's Hospital, Hangzhou, Zhejiang, People's Republic of China
| | - Chang-Zhu Pei
- Reproductive Medicine Center, Yanbian University Hospital, Yanji, Jilin, People's Republic of China.
| | - Linling Zhu
- Department of Reproductive Endocrinology, Zhejiang University School of Medicine, Women's Hospital, Hangzhou, Zhejiang, People's Republic of China.
- Department of Gynecology, Hangzhou Women's Hospital, Hangzhou, Zhejiang, People's Republic of China.
| |
Collapse
|
2
|
Lord S, Johnston H, Samant R, Lai Y. Ubiquitylomics: An Emerging Approach for Profiling Protein Ubiquitylation in Skeletal Muscle. J Cachexia Sarcopenia Muscle 2024; 15:2281-2294. [PMID: 39279720 PMCID: PMC11634490 DOI: 10.1002/jcsm.13601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 07/18/2024] [Accepted: 08/12/2024] [Indexed: 09/18/2024] Open
Abstract
Skeletal muscle is a highly adaptable tissue, finely tuned by various physiological and pathological factors. Whilst the pivotal role of skeletal muscle in overall health is widely acknowledged, unravelling the underlying molecular mechanisms poses ongoing challenges. Protein ubiquitylation, a crucial post-translational modification, is involved in regulating most biological processes. This widespread impact is achieved through a diverse set of enzymes capable of generating structurally and functionally distinct ubiquitin modifications on proteins. The complexity of protein ubiquitylation has presented significant challenges in not only identifying ubiquitylated proteins but also characterising their functional significance. Mass spectrometry enables in-depth analysis of proteins and their post-translational modification status, offering a powerful tool for studying protein ubiquitylation and its biological diversity: an approach termed ubiquitylomics. Ubiquitylomics has been employed to tackle different perspectives of ubiquitylation, including but not limited to global quantification of substrates and ubiquitin linkages, ubiquitin site recognition and crosstalk with other post-translational modifications. As the field of mass spectrometry continues to evolve, the usage of ubiquitylomics has unravelled novel insights into the regulatory mechanisms of protein ubiquitylation governing biology. However, ubiquitylomics research has predominantly been conducted in cellular models, limiting our understanding of ubiquitin signalling events driving skeletal muscle biology. By integrating the intricate landscape of protein ubiquitylation with dynamic shifts in muscle physiology, ubiquitylomics promises to not only deepen our understanding of skeletal muscle biology but also lay the foundation for developing transformative muscle-related therapeutics. This review aims to articulate how ubiquitylomics can be utilised by researchers to address different aspects of ubiquitylation signalling in skeletal muscle. We explore methods used in ubiquitylomics experiments, highlight relevant literature employing ubiquitylomics in the context of skeletal muscle and outline considerations for experimental design.
Collapse
Affiliation(s)
- Samuel O. Lord
- School of Sport, Exercise and Rehabilitation SciencesUniversity of BirminghamBirminghamUK
| | | | | | - Yu‐Chiang Lai
- School of Sport, Exercise and Rehabilitation SciencesUniversity of BirminghamBirminghamUK
- MRC Versus Arthritis Centre for Musculoskeletal Ageing ResearchUniversity of BirminghamBirminghamUK
- NIHR Birmingham Biomedical Research Centre Sarcopenia and MultimorbidityUniversity of BirminghamBirminghamUK
| |
Collapse
|
3
|
Meadow ME, Broas S, Hoare M, Alimohammadi F, Welle KA, Swovick K, Hryhorenko JR, Martinez JC, Biashad SA, Seluanov A, Gorbunova V, Buchwalter A, Ghaemmaghami S. Proteome Birthdating Reveals Age-Selectivity of Protein Ubiquitination. Mol Cell Proteomics 2024; 23:100791. [PMID: 38797438 PMCID: PMC11260378 DOI: 10.1016/j.mcpro.2024.100791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 03/27/2024] [Accepted: 05/15/2024] [Indexed: 05/29/2024] Open
Abstract
Within a cell, proteins have distinct and highly variable half-lives. As a result, the molecular ages of proteins can range from seconds to years. How the age of a protein influences its environmental interactions is a largely unexplored area of biology. To investigate the age-selectivity of cellular pathways, we developed a methodology termed "proteome birthdating" that barcodes proteins based on their time of synthesis. We demonstrate that this approach provides accurate measurements of protein turnover kinetics from a single biological sample encoding multiple labeling time-points. As a first application of the birthdated proteome, we investigated the age distribution of the human ubiquitinome. Our results indicate that the vast majority of ubiquitinated proteins in a cell consist of newly synthesized proteins and that these young proteins constitute the bulk of the degradative flux through the proteasome. Rapidly ubiquitinated nascent proteins are enriched in cytosolic subunits of large protein complexes. Conversely, proteins destined for the secretory pathway and vesicular transport have older ubiquitinated populations. Our data also identify a smaller subset of older ubiquitinated cellular proteins that do not appear to be targeted to the proteasome for rapid degradation. Together, our data provide an age census of the human ubiquitinome and establish proteome birthdating as a robust methodology for investigating the protein age-selectivity of diverse cellular pathways.
Collapse
Affiliation(s)
- Michael E Meadow
- Department of Biology, University of Rochester, New York, USA; Medical Scientist Training Program, University of Rochester, New York, USA
| | - Sarah Broas
- Department of Biology, University of Rochester, New York, USA
| | - Margaret Hoare
- Department of Biology, University of Rochester, New York, USA
| | - Fatemeh Alimohammadi
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, New York, USA
| | - Kevin A Welle
- University of Rochester Mass Spectrometry Resource Laboratory, New York, USA
| | - Kyle Swovick
- University of Rochester Mass Spectrometry Resource Laboratory, New York, USA
| | | | - John C Martinez
- Department of Biology, University of Rochester, New York, USA
| | | | - Andrei Seluanov
- Department of Biology, University of Rochester, New York, USA; Department of Medicine, University of Rochester Medical Center, Rochester, New York, USA
| | - Vera Gorbunova
- Department of Biology, University of Rochester, New York, USA; Department of Medicine, University of Rochester Medical Center, Rochester, New York, USA
| | - Abigail Buchwalter
- Cardiovascular Research Institute, University of California San Francisco, San Francisco, California, USA
| | - Sina Ghaemmaghami
- Department of Biology, University of Rochester, New York, USA; University of Rochester Mass Spectrometry Resource Laboratory, New York, USA.
| |
Collapse
|
4
|
van Overbeek NK, Aguirre T, van der Heden van Noort GJ, Blagoev B, Vertegaal ACO. Deciphering non-canonical ubiquitin signaling: biology and methodology. Front Mol Biosci 2024; 10:1332872. [PMID: 38414868 PMCID: PMC10897730 DOI: 10.3389/fmolb.2023.1332872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Accepted: 12/20/2023] [Indexed: 02/29/2024] Open
Abstract
Ubiquitination is a dynamic post-translational modification that regulates virtually all cellular processes by modulating function, localization, interactions and turnover of thousands of substrates. Canonical ubiquitination involves the enzymatic cascade of E1, E2 and E3 enzymes that conjugate ubiquitin to lysine residues giving rise to monomeric ubiquitination and polymeric ubiquitination. Emerging research has established expansion of the ubiquitin code by non-canonical ubiquitination of N-termini and cysteine, serine and threonine residues. Generic methods for identifying ubiquitin substrates using mass spectrometry based proteomics often overlook non-canonical ubiquitinated substrates, suggesting that numerous undiscovered substrates of this modification exist. Moreover, there is a knowledge gap between in vitro studies and comprehensive understanding of the functional consequence of non-canonical ubiquitination in vivo. Here, we discuss the current knowledge about non-lysine ubiquitination, strategies to map the ubiquitinome and their applicability for studying non-canonical ubiquitination substrates and sites. Furthermore, we elucidate the available chemical biology toolbox and elaborate on missing links required to further unravel this less explored subsection of the ubiquitin system.
Collapse
Affiliation(s)
- Nila K. van Overbeek
- Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, Netherlands
| | - Tim Aguirre
- Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, Netherlands
| | | | - Blagoy Blagoev
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Alfred C. O. Vertegaal
- Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, Netherlands
| |
Collapse
|
5
|
Blaszczak E, Pasquier E, Le Dez G, Odrzywolski A, Lazarewicz N, Brossard A, Fornal E, Moskalek P, Wysocki R, Rabut G. Dissecting Ubiquitylation and DNA Damage Response Pathways in the Yeast Saccharomyces cerevisiae Using a Proteome-Wide Approach. Mol Cell Proteomics 2024; 23:100695. [PMID: 38101750 PMCID: PMC10803944 DOI: 10.1016/j.mcpro.2023.100695] [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: 06/26/2023] [Revised: 11/26/2023] [Accepted: 12/12/2023] [Indexed: 12/17/2023] Open
Abstract
In response to genotoxic stress, cells evolved with a complex signaling network referred to as the DNA damage response (DDR). It is now well established that the DDR depends upon various posttranslational modifications; among them, ubiquitylation plays a key regulatory role. Here, we profiled ubiquitylation in response to the DNA alkylating agent methyl methanesulfonate (MMS) in the budding yeast Saccharomyces cerevisiae using quantitative proteomics. To discover new proteins ubiquitylated upon DNA replication stress, we used stable isotope labeling by amino acids in cell culture, followed by an enrichment of ubiquitylated peptides and LC-MS/MS. In total, we identified 1853 ubiquitylated proteins, including 473 proteins that appeared upregulated more than 2-fold in response to MMS treatment. This enabled us to localize 519 ubiquitylation sites potentially regulated upon MMS in 435 proteins. We demonstrated that the overexpression of some of these proteins renders the cells sensitive to MMS. We also assayed the abundance change upon MMS treatment of a selection of yeast nuclear proteins. Several of them were differentially regulated upon MMS treatment. These findings corroborate the important role of ubiquitin-proteasome-mediated degradation in regulating the DDR.
Collapse
Affiliation(s)
- Ewa Blaszczak
- Department of Genetics and Cell Physiology, Faculty of Biological Sciences, University of Wroclaw, Wroclaw, Poland; Department of Biochemistry and Molecular Biology, Faculty of Medical Sciences, Medical University of Lublin, Lublin, Poland.
| | - Emeline Pasquier
- Univ Rennes, CNRS, INSERM, Institute of Genetics and Development of Rennes (IGDR), UMR 6290, U1305, Rennes, France
| | - Gaëlle Le Dez
- Univ Rennes, CNRS, INSERM, Institute of Genetics and Development of Rennes (IGDR), UMR 6290, U1305, Rennes, France
| | - Adrian Odrzywolski
- Department of Biochemistry and Molecular Biology, Faculty of Medical Sciences, Medical University of Lublin, Lublin, Poland
| | - Natalia Lazarewicz
- Department of Genetics and Cell Physiology, Faculty of Biological Sciences, University of Wroclaw, Wroclaw, Poland; Univ Rennes, CNRS, INSERM, Institute of Genetics and Development of Rennes (IGDR), UMR 6290, U1305, Rennes, France
| | - Audrey Brossard
- Univ Rennes, CNRS, INSERM, Institute of Genetics and Development of Rennes (IGDR), UMR 6290, U1305, Rennes, France
| | - Emilia Fornal
- Department of Bioanalytics, Faculty of Biomedicine, Medical University of Lublin, Lublin, Poland
| | - Piotr Moskalek
- Department of Genetics and Cell Physiology, Faculty of Biological Sciences, University of Wroclaw, Wroclaw, Poland
| | - Robert Wysocki
- Department of Genetics and Cell Physiology, Faculty of Biological Sciences, University of Wroclaw, Wroclaw, Poland.
| | - Gwenaël Rabut
- Univ Rennes, CNRS, INSERM, Institute of Genetics and Development of Rennes (IGDR), UMR 6290, U1305, Rennes, France.
| |
Collapse
|
6
|
Hua Z. Deciphering the protein ubiquitylation system in plants. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:6487-6504. [PMID: 37688404 DOI: 10.1093/jxb/erad354] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Accepted: 09/07/2023] [Indexed: 09/10/2023]
Abstract
Protein ubiquitylation is a post-translational modification (PTM) process that covalently modifies a protein substrate with either mono-ubiquitin moieties or poly-ubiquitin chains often at the lysine residues. In Arabidopsis, bioinformatic predictions have suggested that over 5% of its proteome constitutes the protein ubiquitylation system. Despite advancements in functional genomic studies in plants, only a small fraction of this bioinformatically predicted system has been functionally characterized. To expand our understanding about the regulatory function of protein ubiquitylation to that rivalling several other major systems, such as transcription regulation and epigenetics, I describe the status, issues, and new approaches of protein ubiquitylation studies in plant biology. I summarize the methods utilized in defining the ubiquitylation machinery by bioinformatics, identifying ubiquitylation substrates by proteomics, and characterizing the ubiquitin E3 ligase-substrate pathways by functional genomics. Based on the functional and evolutionary analyses of the F-box gene superfamily, I propose a deleterious duplication model for the large expansion of this family in plant genomes. Given this model, I present new perspectives of future functional genomic studies on the plant ubiquitylation system to focus on core and active groups of ubiquitin E3 ligase genes.
Collapse
Affiliation(s)
- Zhihua Hua
- Department of Environmental and Plant Biology, Ohio University, Athens, OH 45701, USA
- Interdisciplinary Program in Molecular and Cellular Biology, Ohio University, Athens, OH 45701, USA
| |
Collapse
|
7
|
Sathe G, Sapkota GP. Proteomic approaches advancing targeted protein degradation. Trends Pharmacol Sci 2023; 44:786-801. [PMID: 37778939 DOI: 10.1016/j.tips.2023.08.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 08/18/2023] [Accepted: 08/25/2023] [Indexed: 10/03/2023]
Abstract
Targeted protein degradation (TPD) is an emerging modality for research and therapeutics. Most TPD approaches harness cellular ubiquitin-dependent proteolytic pathways. Proteolysis-targeting chimeras (PROTACs) and molecular glue (MG) degraders (MGDs) represent the most advanced TPD approaches, with some already used in clinical settings. Despite these advances, TPD still faces many challenges, pertaining to both the development of effective, selective, and tissue-penetrant degraders and understanding their mode of action. In this review, we focus on progress made in addressing these challenges. In particular, we discuss the utility and application of recent proteomic approaches as indispensable tools to enable insights into degrader development, including target engagement, degradation selectivity, efficacy, safety, and mode of action.
Collapse
Affiliation(s)
- Gajanan Sathe
- MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK.
| | - Gopal P Sapkota
- MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK.
| |
Collapse
|
8
|
Wang XY, Xu YM, Lau ATY. Proteogenomics in Cancer: Then and Now. J Proteome Res 2023; 22:3103-3122. [PMID: 37725793 DOI: 10.1021/acs.jproteome.3c00196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/21/2023]
Abstract
For years, the paths of sequencing technologies and mass spectrometry have occurred in isolation, with each developing its own unique culture and expertise. These two technologies are crucial for inspecting complementary aspects of the molecular phenotype across the central dogma. Integrative multiomics strives to bridge the analysis gap among different fields to complete more comprehensive mechanisms of life events and diseases. Proteogenomics is one integrated multiomics field. Here in this review, we mainly summarize and discuss three aspects: workflow of proteogenomics, proteogenomics applications in cancer research, and the SWOT (Strengths, Weaknesses, Opportunities, Threats) analysis of proteogenomics in cancer research. In conclusion, proteogenomics has a promising future as it clarifies the functional consequences of many unannotated genomic abnormalities or noncanonical variants and identifies driver genes and novel therapeutic targets across cancers, which would substantially accelerate the development of precision oncology.
Collapse
Affiliation(s)
- Xiu-Yun Wang
- Laboratory of Cancer Biology and Epigenetics, Department of Cell Biology and Genetics, Shantou University Medical College, Shantou, Guangdong 515041, People's Republic of China
| | - Yan-Ming Xu
- Laboratory of Cancer Biology and Epigenetics, Department of Cell Biology and Genetics, Shantou University Medical College, Shantou, Guangdong 515041, People's Republic of China
| | - Andy T Y Lau
- Laboratory of Cancer Biology and Epigenetics, Department of Cell Biology and Genetics, Shantou University Medical College, Shantou, Guangdong 515041, People's Republic of China
| |
Collapse
|
9
|
Mostofian B, Martin HJ, Razavi A, Patel S, Allen B, Sherman W, Izaguirre JA. Targeted Protein Degradation: Advances, Challenges, and Prospects for Computational Methods. J Chem Inf Model 2023; 63:5408-5432. [PMID: 37602861 PMCID: PMC10498452 DOI: 10.1021/acs.jcim.3c00603] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Indexed: 08/22/2023]
Abstract
The therapeutic approach of targeted protein degradation (TPD) is gaining momentum due to its potentially superior effects compared with protein inhibition. Recent advancements in the biotech and pharmaceutical sectors have led to the development of compounds that are currently in human trials, with some showing promising clinical results. However, the use of computational tools in TPD is still limited, as it has distinct characteristics compared with traditional computational drug design methods. TPD involves creating a ternary structure (protein-degrader-ligase) responsible for the biological function, such as ubiquitination and subsequent proteasomal degradation, which depends on the spatial orientation of the protein of interest (POI) relative to E2-loaded ubiquitin. Modeling this structure necessitates a unique blend of tools initially developed for small molecules (e.g., docking) and biologics (e.g., protein-protein interaction modeling). Additionally, degrader molecules, particularly heterobifunctional degraders, are generally larger than conventional small molecule drugs, leading to challenges in determining drug-like properties like solubility and permeability. Furthermore, the catalytic nature of TPD makes occupancy-based modeling insufficient. TPD consists of multiple interconnected yet distinct steps, such as POI binding, E3 ligase binding, ternary structure interactions, ubiquitination, and degradation, along with traditional small molecule properties. A comprehensive set of tools is needed to address the dynamic nature of the induced proximity ternary complex and its implications for ubiquitination. In this Perspective, we discuss the current state of computational tools for TPD. We start by describing the series of steps involved in the degradation process and the experimental methods used to characterize them. Then, we delve into a detailed analysis of the computational tools employed in TPD. We also present an integrative approach that has proven successful for degrader design and its impact on project decisions. Finally, we examine the future prospects of computational methods in TPD and the areas with the greatest potential for impact.
Collapse
Affiliation(s)
- Barmak Mostofian
- OpenEye, Cadence Molecular Sciences, Boston, Massachusetts 02114 United States
| | - Holli-Joi Martin
- Laboratory
for Molecular Modeling, Division of Chemical Biology and Medicinal
Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, North Carolina 27599 United States
| | - Asghar Razavi
- ENKO
Chem, Inc, Mystic, Connecticut 06355 United States
| | - Shivam Patel
- Psivant
Therapeutics, Boston, Massachusetts 02210 United States
| | - Bryce Allen
- Differentiated
Therapeutics, San Diego, California 92056 United States
| | - Woody Sherman
- Psivant
Therapeutics, Boston, Massachusetts 02210 United States
| | - Jesus A Izaguirre
- Differentiated
Therapeutics, San Diego, California 92056 United States
- Atommap
Corporation, New York, New York 10013 United States
| |
Collapse
|
10
|
van Wijk KJ, Leppert T, Sun Z, Deutsch EW. Does the Ubiquitination Degradation Pathway Really Reach inside of the Chloroplast? A Re-Evaluation of Mass Spectrometry-Based Assignments of Ubiquitination. J Proteome Res 2023. [PMID: 37092802 DOI: 10.1021/acs.jproteome.3c00178] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
A recent paper in Science Advances by Sun et al. claims that intra-chloroplast proteins in the model plant Arabidopsis can be polyubiquitinated and then extracted into the cytosol for subsequent degradation by the proteasome. Most of this conclusion hinges on several sets of mass spectrometry (MS) data. If the proposed results and conclusion are true, this would be a major change in the proteolysis/proteostasis field, breaking the long-standing dogma that there are no polyubiquitination mechanisms within chloroplast organelles (nor in mitochondria). Given its importance, we reanalyzed their raw MS data using both open and closed sequence database searches and encountered many issues not only with the results but also discrepancies between stated methods (e.g., use of alkylating agent iodoacetamide (IAA)) and observed mass modifications. Although there is likely enrichment of ubiquitination signatures in a subset of the data (probably from ubiquitination in the cytosol), we show that runaway alkylation with IAA caused extensive artifactual modifications of N termini and lysines to the point that a large fraction of the desired ubiquitination signatures is indistinguishable from artifactual acetamide signatures, and thus, no intra-chloroplast polyubiquitination conclusions can be drawn from these data. We provide recommendations on how to avoid such perils in future work.
Collapse
Affiliation(s)
- Klaas J van Wijk
- Section of Plant Biology, School of Integrative Plant Sciences (SIPS), Cornell University, Ithaca, New York 14853, United States
| | - Tami Leppert
- Institute for Systems Biology (ISB), Seattle, Washington 98109, United States
| | - Zhi Sun
- Institute for Systems Biology (ISB), Seattle, Washington 98109, United States
| | - Eric W Deutsch
- Institute for Systems Biology (ISB), Seattle, Washington 98109, United States
| |
Collapse
|
11
|
Kelsall IR. Non-lysine ubiquitylation: Doing things differently. Front Mol Biosci 2022; 9:1008175. [PMID: 36200073 PMCID: PMC9527308 DOI: 10.3389/fmolb.2022.1008175] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Accepted: 09/01/2022] [Indexed: 11/23/2022] Open
Abstract
The post-translational modification of proteins with ubiquitin plays a central role in nearly all aspects of eukaryotic biology. Historically, studies have focused on the conjugation of ubiquitin to lysine residues in substrates, but it is now clear that ubiquitylation can also occur on cysteine, serine, and threonine residues, as well as on the N-terminal amino group of proteins. Paradigm-shifting reports of non-proteinaceous substrates have further extended the reach of ubiquitylation beyond the proteome to include intracellular lipids and sugars. Additionally, results from bacteria have revealed novel ways to ubiquitylate (and deubiquitylate) substrates without the need for any of the enzymatic components of the canonical ubiquitylation cascade. Focusing mainly upon recent findings, this review aims to outline the current understanding of non-lysine ubiquitylation and speculate upon the molecular mechanisms and physiological importance of this non-canonical modification.
Collapse
|