1
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Reinbold C, Kong KYE, Kats I, Khmelinskii A, Knop M. Multiplexed protein stability (MPS) profiling of terminal degrons using fluorescent timer libraries in Saccharomyces cerevisiae. Methods Enzymol 2023; 686:321-344. [PMID: 37532406 DOI: 10.1016/bs.mie.2023.02.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/04/2023]
Abstract
N-terminal protein sequences and their proteolytic processing and modifications influence the stability and turnover of proteins by creating potential degrons for cellular proteolytic pathways. Understanding the impact of genetic perturbations of components affecting the processing of protein N-termini and thereby their stability, requires methods compatible with proteome-wide studies of many N-termini simultaneously. Tandem fluorescent timers (tFT) allow the in vivo measurement of protein turnover completely independent of protein abundance and can be deployed for proteome-wide studies. Here we present a protocol for Multiplexed Protein Stability (MPS) profiling of tFT-libraries encoding large numbers of different protein N-termini fused to tFT in the yeast Saccharomyces cerevisiae. This protocol includes fluorescence cell sorting based profiling of these libraries using a pooling approach. Analysis of the sorted pools is done by using multiplexed deep sequencing, in order to generate a stability index for each N-terminally peptide fused to the tFT reporter, and to evaluate half-life changes across all species represented in the library.
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Affiliation(s)
- Christian Reinbold
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany
| | | | - Ilia Kats
- Division of Computational Genomics and Systems Genetics, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | | | - Michael Knop
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany; Cell Morphogenesis and Signal Transduction, German Cancer Research Center (DKFZ), DKFZ-ZMBH Alliance, Heidelberg, Germany.
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2
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Wang N, Gao JG, Wu MW. Molecular docking and molecular simulation studies for N-degron selectivity of chloroplastic ClpS from Chlamydomonas reinhardtii. Comput Biol Chem 2023; 103:107825. [PMID: 36773520 DOI: 10.1016/j.compbiolchem.2023.107825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2022] [Revised: 01/31/2023] [Accepted: 02/02/2023] [Indexed: 02/11/2023]
Abstract
Regarding the importance of N-degron pathway in protein degradation network, the adaptor protein ClpS recognizes the substrates bearing classical N-degrons, and delivers them to caseinolytic protease complex ClpAP for degradation. Interestingly, the majority of N-degrons located near the N-terminus of protein substrate are belonged to the hydrophobic type amino acids. Chloroplast, an important organelle for plant photosynthesis, contain a diversified Clp degradation system. Despite several studies have confirmed that chloroplastic ClpS is able to interact with classical N-degrons derived from prokaryotes, whereas, the molecular mechanism underlying how the chloroplastic ClpS protein could recognize the substrate tagged by N-degrons is still unclear until now. Chlamydomonas reinhardtii is a kind of unicellular model organism for photosynthesis researches, which possesses a large cup-shaped chloroplast, and the corresponding genome data indicates that it owns bacterial homologous adaptor protein, named CrClpS1. However, the relevant biochemical knowledges, and protein structure researches for CrClpS1 adaptor aren't reported up to date. The molecular interactions between CrClpS1 and possible N-degrons are undefined as well. Here, we build a reliable homology model of CrClpS1 and find a hydrophobic pocket for N-degron binding. We combine molecular docking, molecular dynamic simulations, and MM/PBSA, MM/GBSA binding free energy estimations to elucidate the molecular properties of CrClpS1-N-degron interactions. Besides, we investigate the conformational changes for CrClpS1-apo in water-solvent environment and analyze its possible biological significances through a long time molecular dynamic simulation. Specifically, the adaptor CrClpS1 displays the stronger interactions with Phe, Trp, Tyr, His and Ile with respect to other amino acids. Using the residue decomposition analysis, the interactions between CrClpS1 and N-degrons are heavily depended on several conservative residues, which are located around the hydrophobic pocket, implying that chloroplast isolated from Chlamydomonas reinhadtii adopts a relatively conservative N-degron recognition mode. Besides, the opening-closure of hydrophobic pocket of CrClpS1 might be beneficial for the N-degron selectivity.
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Affiliation(s)
- Ning Wang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100101, China.
| | - Jian-Guo Gao
- Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science and Technology, Xinjiang University, Urumqi, China
| | - Ming-Wei Wu
- University of Chinese Academy of Sciences, Beijing 100101, China; Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
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3
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Müller F, Bange T. Identification of N-degrons and N-recognins using peptide pull-downs combined with quantitative mass spectrometry. Methods Enzymol 2023; 686:67-97. [PMID: 37532409 DOI: 10.1016/bs.mie.2023.02.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/04/2023]
Abstract
Regulated protein degradation controls protein levels of all short-lived proteins to ensure cellular homeostasis and also protects cells from misfolded or other abnormal proteins. The most important players in the degradation system are E3 ubiquitin ligases which recognize exposed sequence motifs, so-called degrons, of target proteins and mark them through the attachment of ubiquitin for degradation. N-terminal (Nt) sequences are extensively used as degrons (N-degrons) and all 20 amino acids are able to feed proteins in 1 of the 5 known N-degron pathways. Studies have mainly focused on characterizing systematically the role of the starting amino acid on protein stability and less on the identification of the E3 ligases involved. Recent data from our lab and literature suggest that there is an extensive interplay of N-recognins and Nt-modifying enzymes like Nt-acetyltransferases (NATs) or N-myristoyltransferases which only starts to be elucidated. It suggests that improperly modified or unexpectedly unmodified proteins become rapidly removed after synthesis ensuring protein maturation and quality control of specific subsets of proteins. Here, we describe a peptide pull-down and down-stream bioinformatics workflow conducted in the MaxQuant and Perseus computational environment to identify N-recognin candidates in an unbiased way using quantitative mass spectrometry (MS)-based proteomics. Our workflow allows the identification of N-recognin candidates for specific N-degrons, to determine their sequence specificity and it can be applied as well more general to identify binding partners of N-terminal modifications. This method paves the way to identify pathways involved in protein quality control and stability acting at the N-terminus.
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Affiliation(s)
- Franziska Müller
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Tanja Bange
- Institute of Medical Psychology, Faculty of Medicine, Ludwig-Maximilians University, Munich, Germany.
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4
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Donzelli L, Bolgi O, Geiss-Friedlander R. The amino-dipeptidyl peptidases DPP8 and DPP9: Purification and enzymatic assays. Methods Enzymol 2023; 684:289-323. [PMID: 37230592 DOI: 10.1016/bs.mie.2023.02.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Proline residues highly impact protein stability when present either in the first or second N-terminal position. While the human genome encodes for more than 500 proteases, only few proteases are capable of hydrolyzing a proline-containing peptide bond. The two intra-cellular amino-dipeptidyl peptidases DPP8 and DPP9 are exceptional as they possess the rare ability to cleave post-proline. By removing N-terminal Xaa-Pro dipeptides, DPP8 and DPP9 expose a neo N-terminus of their substates, which can consequently alter inter- or intra-molecular interactions of the modified protein. Both DPP8 and DPP9 play key roles in the immune response and are linked to cancer progression, emerging as attractive drug targets. DPP9 is more abundant than DPP8 and is rate limiting for cleavage of cytosolic proline-containing peptides. Only few DPP9 substrates have been characterized; these include Syk, a central kinase for B-cell receptor mediated signaling; Adenylate Kinase 2 (AK2) which is important for cellular energy homeostasis; and the tumor suppressor Breast cancer type 2 susceptibility protein (BRCA2) that is critical for repair of DNA double strand breaks. N-terminal processing of these proteins by DPP9 triggers their rapid turn-over by the proteasome, highlighting a role for DPP9 as upstream components of the N-degron pathway. Whether N-terminal processing by DPP9 leads to substrate-degradation in all cases, or whether additional outcomes are possible, remains to be tested. In this chapter we will describe methods for purification of DPP8 and DPP9 as well as protocols for biochemical and enzymatic characterization of these proteases.
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Affiliation(s)
- Laura Donzelli
- Institute of Molecular Medicine and Cell Research, Medical Faculty, University of Freiburg, Freiburg, Germany
| | - Oguz Bolgi
- Institute of Molecular Medicine and Cell Research, Medical Faculty, University of Freiburg, Freiburg, Germany
| | - Ruth Geiss-Friedlander
- Institute of Molecular Medicine and Cell Research, Medical Faculty, University of Freiburg, Freiburg, Germany.
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5
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Seo DY, Kim D, Nguyen KT, Oh J, Lee JS, Hwang CS. N-Terminally arginylated ubiquitin is attached to histone H2A by RING1B E3 ligase in human cells. Biochem Biophys Res Commun 2023; 666:186-194. [PMID: 36932026 DOI: 10.1016/j.bbrc.2023.02.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 02/09/2023] [Indexed: 02/11/2023]
Abstract
Ubiquitin (Ub) is highly conserved in all eukaryotic organisms and begins at the N-terminus with Met and Gln. Our recent research demonstrates that N-terminally (Nt-) arginylated Ub can be produced in the yeast Saccharomyces cerevisiae. However, the existence of Nt-arginylated Ub in multicellular organisms remains unknown. Here we explore the mechanism for creating Nt-arginylated Ub using human embryonic kidney HEK293 cells that express various Nt-modified Ubs. We found that Gln-starting Q-Ub was converted into Glu-starting E-Ub by NTAQ1 Nt-deamidase and subsequently Nt-arginylated by ATE1 arginyltransferase in HEK293 cells. We also found that the resulting Arg-Glu-starting RE-Ub was mainly deposited on the Lys119 residue of histone H2A. Furthermore, RING1B E3 Ub ligase mediated the attachment of RE-Ub to H2A. These findings reveal a previously unknown type of histone ubiquitylation which greatly increases the combinatorial complexity of histone and ubiquitin codes.
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Affiliation(s)
- Dong-Young Seo
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk, 37673, Republic of Korea
| | - Dasom Kim
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk, 37673, Republic of Korea
| | - Kha The Nguyen
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk, 37673, Republic of Korea
| | - Junsoo Oh
- Department of Molecular Bioscience, College of Biomedical Science, Kangwon National University, Chuncheon, Kangwon, 24341, Republic of Korea
| | - Jung-Shin Lee
- Department of Molecular Bioscience, College of Biomedical Science, Kangwon National University, Chuncheon, Kangwon, 24341, Republic of Korea
| | - Cheol-Sang Hwang
- Department of Life Sciences, Korea University, Seoul, 02841, Republic of Korea.
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6
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Rovere M, Pucciariello C, Castella C, Berger A, Forgia M, Guyet TA, Bosseno M, Pacoud M, Brouquisse R, Perata P, Boscari A. Group VII ethylene response factors, MtERF74 and MtERF75, sustain nitrogen fixation in Medicago truncatula microoxic nodules. Plant Cell Environ 2023; 46:607-620. [PMID: 36479691 DOI: 10.1111/pce.14505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 12/02/2022] [Accepted: 12/04/2022] [Indexed: 06/17/2023]
Abstract
Group VII ethylene response factors (ERF-VII) are plant-specific transcription factors (TFs) known for their role in the activation of hypoxia-responsive genes under low oxygen stress but also in plant endogenous hypoxic niches. However, their function in the microaerophilic nitrogen-fixing nodules of legumes has not yet been investigated. We investigated regulation and the function of the two Medicago truncatula ERF-VII TFs (MtERF74 and MtERF75) in roots and nodules, MtERF74 and MtERF75 in response to hypoxia stress and during the nodulation process using an RNA interference strategy and targeted proteolysis of MtERF75. Knockdown of MtERF74 and MtERF75 partially blocked the induction of hypoxia-responsive genes in roots exposed to hypoxia stress. In addition, a significant reduction in nodulation capacity and nitrogen fixation activity was observed in mature nodules of double knockdown transgenic roots. Overall, the results indicate that MtERF74 and MtERF75 are involved in the induction of MtNR1 and Pgb1.1 expression for efficient Phytogb-nitric oxide respiration in the nodule.
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Affiliation(s)
- Martina Rovere
- Université Côte d'Azur, INRAE, CNRS, ISA, Sophia Antipolis, France
| | - Chiara Pucciariello
- PlantLab, Institute of Life Sciences, Scuola Superiore Sant'Anna, Pisa, Italy
| | - Claude Castella
- INRAE, UR1115 Plantes et Systèmes de culture Horticoles (PSH), Site Agroparc, Avignon, France
| | - Antoine Berger
- Agroécologie, AgroSup Dijon, CNRS, INRAE, University of Bourgogne Franche-Comté, Dijon, France
| | - Marco Forgia
- Université Côte d'Azur, INRAE, CNRS, ISA, Sophia Antipolis, France
| | - Tran A Guyet
- PlantLab, Institute of Life Sciences, Scuola Superiore Sant'Anna, Pisa, Italy
| | - Marc Bosseno
- Université Côte d'Azur, INRAE, CNRS, ISA, Sophia Antipolis, France
| | - Marie Pacoud
- Université Côte d'Azur, INRAE, CNRS, ISA, Sophia Antipolis, France
| | | | - Pierdomenico Perata
- PlantLab, Institute of Life Sciences, Scuola Superiore Sant'Anna, Pisa, Italy
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7
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Bolgi O, Silva-Garcia M, Ross B, Pilla E, Kari V, Killisch M, Spitzner M, Stark N, Lenz C, Weiss K, Donzelli L, Gorrell MD, Grade M, Riemer J, Urlaub H, Dobbelstein M, Huber R, Geiss-Friedlander R. Dipeptidyl peptidase 9 triggers BRCA2 degradation and promotes DNA damage repair. EMBO Rep 2022; 23:e54136. [PMID: 35912982 PMCID: PMC9535758 DOI: 10.15252/embr.202154136] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 07/01/2022] [Accepted: 07/07/2022] [Indexed: 12/30/2022] Open
Abstract
N-terminal sequences are important sites for post-translational modifications that alter protein localization, activity, and stability. Dipeptidyl peptidase 9 (DPP9) is a serine aminopeptidase with the rare ability to cleave off N-terminal dipeptides with imino acid proline in the second position. Here, we identify the tumor-suppressor BRCA2 as a DPP9 substrate and show this interaction to be induced by DNA damage. We present crystallographic structures documenting intracrystalline enzymatic activity of DPP9, with the N-terminal Met1-Pro2 of a BRCA21-40 peptide captured in its active site. Intriguingly, DPP9-depleted cells are hypersensitive to genotoxic agents and are impaired in the repair of DNA double-strand breaks by homologous recombination. Mechanistically, DPP9 targets BRCA2 for degradation and promotes the formation of RAD51 foci, the downstream function of BRCA2. N-terminal truncation mutants of BRCA2 that mimic a DPP9 product phenocopy reduced BRCA2 stability and rescue RAD51 foci formation in DPP9-deficient cells. Taken together, we present DPP9 as a regulator of BRCA2 stability and propose that by fine-tuning the cellular concentrations of BRCA2, DPP9 alters the BRCA2 interactome, providing a possible explanation for DPP9's role in cancer.
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Affiliation(s)
- Oguz Bolgi
- Institute of Molecular Medicine and Cell Research, Medical Faculty, University of Freiburg, Freiburg, Germany.,Department of Molecular Biology, University Medical Center Göttingen, Göttingen, Germany
| | - Maria Silva-Garcia
- Department of Molecular Biology, University Medical Center Göttingen, Göttingen, Germany
| | - Breyan Ross
- Max Planck Institut für Biochemie, Martinsried, Germany.,Proteros Biostructures GmbH, Martinsried, Germany
| | - Esther Pilla
- Department of Molecular Biology, University Medical Center Göttingen, Göttingen, Germany
| | - Vijayalakshmi Kari
- Department of General, Visceral and Pediatric Surgery, University Medical Center Göttingen, Göttingen, Germany
| | - Markus Killisch
- Department of Molecular Biology, University Medical Center Göttingen, Göttingen, Germany
| | - Melanie Spitzner
- Department of General, Visceral and Pediatric Surgery, University Medical Center Göttingen, Göttingen, Germany
| | - Nadine Stark
- Institute of Molecular Oncology, Göttingen Center of Molecular Biosciences (GZMB), University Medical Center Göttingen, Göttingen, Germany
| | - Christof Lenz
- Bioanalytics, Institute of Clinical Chemistry, University Medical Center, Göttingen, Germany.,Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Konstantin Weiss
- Institute of Biochemistry, Redox Biochemistry, and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Laura Donzelli
- Institute of Molecular Medicine and Cell Research, Medical Faculty, University of Freiburg, Freiburg, Germany
| | - Mark D Gorrell
- Centenary Institute, The University of Sydney Faculty of Medicine and Health, Sydney, NSW, Australia
| | - Marian Grade
- Department of General, Visceral and Pediatric Surgery, University Medical Center Göttingen, Göttingen, Germany
| | - Jan Riemer
- Institute of Biochemistry, Redox Biochemistry, and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Henning Urlaub
- Bioanalytics, Institute of Clinical Chemistry, University Medical Center, Göttingen, Germany.,Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Matthias Dobbelstein
- Institute of Molecular Oncology, Göttingen Center of Molecular Biosciences (GZMB), University Medical Center Göttingen, Göttingen, Germany
| | - Robert Huber
- Max Planck Institut für Biochemie, Martinsried, Germany.,Zentrum für Medizinische Biotechnologie, Universität Duisburg-Essen, Essen, Germany.,Fakultät für Chemie, Technische Universität München, Garching, Germany
| | - Ruth Geiss-Friedlander
- Institute of Molecular Medicine and Cell Research, Medical Faculty, University of Freiburg, Freiburg, Germany.,Department of Molecular Biology, University Medical Center Göttingen, Göttingen, Germany
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8
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Willems P, Huesgen PF, Finkemeier I, Graciet E, Meinnel T, Van Breusegem F. Editorial: Plant protein termini: Their generation, modification and function. Front Plant Sci 2022; 13:1040392. [PMID: 36247598 PMCID: PMC9562973 DOI: 10.3389/fpls.2022.1040392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Accepted: 09/15/2022] [Indexed: 06/16/2023]
Affiliation(s)
- Patrick Willems
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- Vlaams Instituut voor Biotechnologie (VIB) Center for Plant Systems Biology, Vlaams Instituut voor Biotechnologie (VIB), Ghent, Belgium
- Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
- Vlaams Instituut voor Biotechnologie (VIB) Center for Medical Biotechnology, Vlaams Instituut voor Biotechnologie (VIB), Ghent, Belgium
| | - Pitter F. Huesgen
- Central Institute for Engineering, Electronics and Analytics, ZEA-3, Forschungszentrum Jülich, Jülich, Germany
- Cologne Excellence Cluster on Stress Responses in Ageing-Associated Diseases, CECAD, Medical Faculty and University Hospital, University of Cologne, Cologne, Germany
- Institute of Biochemistry, Department for Chemistry, University of Cologne, Cologne, Germany
| | - Iris Finkemeier
- Plant Physiology, Institute of Plant Biology and Biotechnology, University of Muenster, Münster, Germany
| | - Emmanuelle Graciet
- Department of Biology, Maynooth University, Maynooth, Ireland
- Kathleen Lonsdale Institute for Human Health Research, Maynooth University, Maynooth, Ireland
| | - Thierry Meinnel
- Université Paris-Saclay, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Centre National de la Recherche Scientifique (CNRS), Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Frank Van Breusegem
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- Vlaams Instituut voor Biotechnologie (VIB) Center for Plant Systems Biology, Vlaams Instituut voor Biotechnologie (VIB), Ghent, Belgium
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9
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Nguyen KT, Ju S, Kim SY, Lee CS, Lee C, Hwang CS. N-Terminal Modifications of Ubiquitin via Methionine Excision, Deamination, and Arginylation Expand the Ubiquitin Code. Mol Cells 2022; 45:158-167. [PMID: 35253655 PMCID: PMC8926867 DOI: 10.14348/molcells.2022.2027] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 12/16/2021] [Accepted: 01/12/2022] [Indexed: 11/27/2022] Open
Abstract
Ubiquitin (Ub) is post-translationally modified by Ub itself or Ub-like proteins, phosphorylation, and acetylation, among others, which elicits a variety of Ub topologies and cellular functions. However, N-terminal (Nt) modifications of Ub remain unknown, except the linear head-to-tail ubiquitylation via Nt-Met. Here, using the yeast Saccharomyces cerevisiae and an Nt-arginylated Ub-specific antibody, we found that the detectable level of Ub undergoes Nt-Met excision, Nt-deamination, and Nt-arginylation. The resulting Nt-arginylated Ub and its conjugated proteins are upregulated in the stationary-growth phase or by oxidative stress. We further proved the existence of Nt-arginylated Ub in vivo and identified Nt-arginylated Ub-protein conjugates using stable isotope labeling by amino acids in cell culture (SILAC)-based tandem mass spectrometry. In silico structural modeling of Nt-arginylated Ub predicted that Nt-Arg flexibly protrudes from the surface of the Ub, thereby most likely providing a docking site for the factors that recognize it. Collectively, these results reveal unprecedented Nt-arginylated Ub and the pathway by which it is produced, which greatly expands the known complexity of the Ub code.
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Affiliation(s)
- Kha The Nguyen
- Department of Life Sciences, Pohang University of Science and Technology, Pohang 37673, Korea
| | - Shinyeong Ju
- Center for Theragnosis, Korea Institute of Science and Technology, Seoul 02792, Korea
| | - Sang-Yoon Kim
- Department of Life Sciences, Pohang University of Science and Technology, Pohang 37673, Korea
| | - Chang-Seok Lee
- Department of Life Sciences, Pohang University of Science and Technology, Pohang 37673, Korea
| | - Cheolju Lee
- Center for Theragnosis, Korea Institute of Science and Technology, Seoul 02792, Korea
- Division of Bio-Medical Science & Technology, KIST School, Korea University of Science and Technology, Seoul 02792, Korea
| | - Cheol-Sang Hwang
- Department of Life Sciences, Pohang University of Science and Technology, Pohang 37673, Korea
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10
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Sherpa D, Chrustowicz J, Schulman BA. How the ends signal the end: Regulation by E3 ubiquitin ligases recognizing protein termini. Mol Cell 2022; 82:1424-1438. [PMID: 35247307 PMCID: PMC9098119 DOI: 10.1016/j.molcel.2022.02.004] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 01/18/2022] [Accepted: 02/01/2022] [Indexed: 12/31/2022]
Abstract
Specificity of eukaryotic protein degradation is determined by E3 ubiquitin ligases and their selective binding to protein motifs, termed "degrons," in substrates for ubiquitin-mediated proteolysis. From the discovery of the first substrate degron and the corresponding E3 to a flurry of recent studies enabled by modern systems and structural methods, it is clear that many regulatory pathways depend on E3s recognizing protein termini. Here, we review the structural basis for recognition of protein termini by E3s and how this recognition underlies biological regulation. Diverse E3s evolved to harness a substrate's N and/or C terminus (and often adjacent residues as well) in a sequence-specific manner. Regulation is achieved through selective activation of E3s and also through generation of degrons at ribosomes or by posttranslational means. Collectively, many E3 interactions with protein N and C termini enable intricate control of protein quality and responses to cellular signals.
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Affiliation(s)
- Dawafuti Sherpa
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Martinsried, Bavaria, Germany
| | - Jakub Chrustowicz
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Martinsried, Bavaria, Germany
| | - Brenda A Schulman
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Martinsried, Bavaria, Germany.
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11
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Eldeeb MA, Ragheb MA, Soliman MH, Fahlman RP. Regulation of Neurodegeneration-associated Protein Fragments by the N-degron Pathways. Neurotox Res 2022; 40:298-318. [PMID: 35043375 DOI: 10.1007/s12640-021-00396-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 07/20/2021] [Accepted: 07/20/2021] [Indexed: 12/20/2022]
Abstract
Among the most salient features that underpin the development of aging-related neurodegenerative disorders are the accumulation of protein aggregates and the decrease in cellular degradation capacity. Mammalian cells have evolved sophisticated quality control mechanisms to repair or eliminate the otherwise abnormal or misfolded proteins. Chaperones identify unstable or abnormal conformations in proteins and often help them regain their correct conformation. However, if repair is not an option, abnormal proteins are selectively degraded to prevent undesired interactions with other proteins or oligomerization into toxic multimeric complexes. The autophagic-lysosomal system and the ubiquitin-proteasome system mediate the selective and targeted degradation of abnormal or aberrant protein fragments. Despite an increasing understanding regarding the molecular responses that counteract the formation and clearance of dysfunctional protein aggregates, the role of N-degrons in these processes is poorly understood. Previous work demonstrated that the Arg-N-end rule degradation pathway (Arg-N-degron pathway) mediates the degradation of neurodegeneration-associated proteins, thereby regulating crucial signaling hubs that modulate the progression of neurodegenerative diseases. Herein, we discuss the functional interconnection between N-degron pathways and proteins associated with neurodegenerative disorders, including Alzheimer's disease, amyotrophic lateral sclerosis, and Parkinson's disease. We also highlight some future prospects related to how the molecular insights gained from these processes will help unveil novel therapeutic approaches.
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Affiliation(s)
- Mohamed A Eldeeb
- Chemistry Department (Biochemistry Division), Faculty of Science, Cairo University, Giza, Egypt. .,Neurodegenerative Diseases Group, Department of Neurology and Neurosurgery, McGill Parkinson Program, Montreal Neurological Institute, McGill University, Montreal, QC, Canada.
| | - Mohamed A Ragheb
- Chemistry Department (Biochemistry Division), Faculty of Science, Cairo University, Giza, Egypt
| | - Marwa H Soliman
- Chemistry Department (Biochemistry Division), Faculty of Science, Cairo University, Giza, Egypt
| | - Richard P Fahlman
- Department of Biochemistry, University of Alberta, Edmonton, AB, Canada
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12
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Huber M, Armbruster L, Etherington RD, De La Torre C, Hawkesford MJ, Sticht C, Gibbs DJ, Hell R, Wirtz M. Disruption of the N α-Acetyltransferase NatB Causes Sensitivity to Reductive Stress in Arabidopsis thaliana. Front Plant Sci 2022; 12:799954. [PMID: 35046984 PMCID: PMC8761761 DOI: 10.3389/fpls.2021.799954] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Accepted: 11/22/2021] [Indexed: 06/14/2023]
Abstract
In Arabidopsis thaliana, the evolutionary conserved N-terminal acetyltransferase (Nat) complexes NatA and NatB co-translationally acetylate 60% of the proteome. Both have recently been implicated in the regulation of plant stress responses. While NatA mediates drought tolerance, NatB is required for pathogen resistance and the adaptation to high salinity and high osmolarity. Salt and osmotic stress impair protein folding and result in the accumulation of misfolded proteins in the endoplasmic reticulum (ER). The ER-membrane resident E3 ubiquitin ligase DOA10 targets misfolded proteins for degradation during ER stress and is conserved among eukaryotes. In yeast, DOA10 recognizes conditional degradation signals (Ac/N-degrons) created by NatA and NatB. Assuming that this mechanism is preserved in plants, the lack of Ac/N-degrons required for efficient removal of misfolded proteins might explain the sensitivity of NatB mutants to protein harming conditions. In this study, we investigate the response of NatB mutants to dithiothreitol (DTT) and tunicamycin (TM)-induced ER stress. We report that NatB mutants are hypersensitive to DTT but not TM, suggesting that the DTT hypersensitivity is caused by an over-reduction of the cytosol rather than an accumulation of unfolded proteins in the ER. In line with this hypothesis, the cytosol of NatB depleted plants is constitutively over-reduced and a global transcriptome analysis reveals that their reductive stress response is permanently activated. Moreover, we demonstrate that doa10 mutants are susceptible to neither DTT nor TM, ruling out a substantial role of DOA10 in ER-associated protein degradation (ERAD) in plants. Contrary to previous findings in yeast, our data indicate that N-terminal acetylation (NTA) does not inhibit ER targeting of a substantial amount of proteins in plants. In summary, we provide further evidence that NatB-mediated imprinting of the proteome is vital for the response to protein harming stress and rule out DOA10 as the sole recognin for substrates in the plant ERAD pathway, leaving the role of DOA10 in plants ambiguous.
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Affiliation(s)
- Monika Huber
- Centre for Organismal Studies, Molecular Biology of Plants Group, Heidelberg University, Heidelberg, Germany
| | - Laura Armbruster
- Centre for Organismal Studies, Molecular Biology of Plants Group, Heidelberg University, Heidelberg, Germany
| | | | - Carolina De La Torre
- Institute of Clinical Chemistry, NGS Core Facility, Medical Faculty Mannheim of Heidelberg University, Heidelberg, Germany
| | | | - Carsten Sticht
- Institute of Clinical Chemistry, NGS Core Facility, Medical Faculty Mannheim of Heidelberg University, Heidelberg, Germany
| | - Daniel J. Gibbs
- School of Biosciences, University of Birmingham, Edgbaston, United Kingdom
| | - Rüdiger Hell
- Centre for Organismal Studies, Molecular Biology of Plants Group, Heidelberg University, Heidelberg, Germany
| | - Markus Wirtz
- Centre for Organismal Studies, Molecular Biology of Plants Group, Heidelberg University, Heidelberg, Germany
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13
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Shin JS, Park SH, Kim L, Heo J, Song HK. Crystal structure of yeast Gid10 in complex with Pro/ N-degron. Biochem Biophys Res Commun 2021; 582:86-92. [PMID: 34695755 DOI: 10.1016/j.bbrc.2021.10.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 10/03/2021] [Indexed: 11/22/2022]
Abstract
The cellular glucose level has to be tightly regulated by a variety of cellular processes. One of them is the degradation of gluconeogenic enzymes such as Fbp1, Icl1, Mdh2, and Pck1 by GID (glucose-induced degradation deficient) E3 ubiquitin ligase. The Gid4 component of the GID ligase complex is responsible for recognizing the N-terminal proline residue of the target substrates under normal conditions. However, an alternative N-recognin Gid10 controls the degradation process under stressed conditions. Although Gid10 shares a high sequence similarity with Gid4, their substrate specificities are quite different. Here, we report the structure of Gid10 from Saccharomyces cerevisiae in complex with Pro/N-degron, Pro-Tyr-Ile-Thr, which is almost identical to the sequence of the natural substrate Art2. Although Gid10 shares many structural features with the Gid4 protein from yeast and humans, the current structure explains the unique structural difference for the preference of bulky hydrophobic residue at the second position of Pro/N-degron. Therefore, this study provides a fundamental basis for understanding of the structural diversity and substrate specificity of recognition components in the GID E3 ligase complex involved in the Pro/N-degron pathway.
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14
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Kim JG, Shin HC, Seo T, Nawale L, Han G, Kim BY, Kim SJ, Cha-Molstad H. Signaling Pathways Regulated by UBR Box-Containing E3 Ligases. Int J Mol Sci 2021; 22:8323. [PMID: 34361089 DOI: 10.3390/ijms22158323] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 07/28/2021] [Accepted: 07/29/2021] [Indexed: 12/31/2022] Open
Abstract
UBR box E3 ligases, also called N-recognins, are integral components of the N-degron pathway. Representative N-recognins include UBR1, UBR2, UBR4, and UBR5, and they bind destabilizing N-terminal residues, termed N-degrons. Understanding the molecular bases of their substrate recognition and the biological impact of the clearance of their substrates on cellular signaling pathways can provide valuable insights into the regulation of these pathways. This review provides an overview of the current knowledge of the binding mechanism of UBR box N-recognin/N-degron interactions and their roles in signaling pathways linked to G-protein-coupled receptors, apoptosis, mitochondrial quality control, inflammation, and DNA damage. The targeting of these UBR box N-recognins can provide potential therapies to treat diseases such as cancer and neurodegenerative diseases.
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15
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Eldeeb MA. N-Terminal-Dependent Protein Degradation and Targeting Cancer Cells. Anticancer Agents Med Chem 2021; 21:231-236. [PMID: 32814541 DOI: 10.2174/1871520620666200819112632] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 03/11/2020] [Accepted: 04/19/2020] [Indexed: 11/22/2022]
Abstract
Intracellular protein degradation is mediated selectively by the Ubiquitin-Proteasome System (UPS) and autophagic-lysosomal system in mammalian cells. Many cellular and physiological processes, such as cell division, cell differentiation, and cellular demise, are fine-tuned via the UPS-mediated protein degradation. Notably, impairment of UPS contributes to human disorders, including cancer and neurodegeneration. The proteasome- dependent N-degron pathways mediate the degradation of proteins through their destabilizing aminoterminal residues. Recent advances unveiled that targeting N-degron proteolytic pathways can aid in sensitizing some cancer cells to chemotherapeutic agents. Furthermore, interestingly, exploiting the N-degron feature, the simplest degradation signal in mammals, and fusing it to a ligand specific for Estrogen-Related Receptor alpha (ERRa) has demonstrated its utility in ERRa knockdown, via N-terminal dependent degradation, and also its efficiency in the inhibition of growth of breast cancer cells. These recent advances uncover the therapeutic implications of targeting and exploiting N-degron proteolytic pathways to curb growth and migration of cancer cells.
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Affiliation(s)
- Mohamed A Eldeeb
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC, Canada
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16
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Winter N, Novatchkova M, Bachmair A. Cellular Control of Protein Turnover via the Modification of the Amino Terminus. Int J Mol Sci 2021; 22:ijms22073545. [PMID: 33805528 PMCID: PMC8037982 DOI: 10.3390/ijms22073545] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 03/22/2021] [Accepted: 03/24/2021] [Indexed: 12/13/2022] Open
Abstract
The first amino acid of a protein has an important influence on its metabolic stability. A number of ubiquitin ligases contain binding domains for different amino-terminal residues of their substrates, also known as N-degrons, thereby mediating turnover. This review summarizes, in an exemplary way, both older and more recent findings that unveil how destabilizing amino termini are generated. In most cases, a step of proteolytic cleavage is involved. Among the over 500 proteases encoded in the genome of higher eukaryotes, only a few are known to contribute to the generation of N-degrons. It can, therefore, be expected that many processing paths remain to be discovered.
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Affiliation(s)
- Nikola Winter
- Max Perutz Labs, Department of Biochemistry and Cell Biology, University of Vienna, A-1030 Vienna, Austria;
| | - Maria Novatchkova
- Vienna BioCenter, Research Institute of Molecular Pathology, A-1030 Vienna, Austria;
- Vienna BioCenter, Institute of Molecular Biotechnology, A-1030 Vienna, Austria
| | - Andreas Bachmair
- Max Perutz Labs, Department of Biochemistry and Cell Biology, University of Vienna, A-1030 Vienna, Austria;
- Correspondence:
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17
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Abstract
In mammals, protein degradation is mediated selectively by the ubiquitin proteasome system (UPS) and the autophagic-lysosomal system. Over the past decades, N-degron pathways have been shown to be responsible for the selective degradation of proteins that harbor destabilizing N-terminal motifs. Recent studies have employed these pathways in the development of proteolysis targeting chimeras (PROTACs) composed of a degradation module linked to a substrate recognition domain to target proteins encoded by cancer-related genes for proteasomal destruction. Herein we provide an overview of PROTACs in the context of the N-degron concept and address the application of this technique to curb the migration and invasion of cancer cells, with a focus on the far-reaching potential of exploiting N-degron pathways for therapeutic purposes.
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Affiliation(s)
- Mohamed A Eldeeb
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Cornelia E Zorca
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Richard P Fahlman
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
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18
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Eldeeb MA, Zorca CE, Ragheb MA, Rashidi FB, Salah El-Din DS. Fine-tuning ER-phagy by post-translational modifications. Bioessays 2020; 43:e2000212. [PMID: 33210303 DOI: 10.1002/bies.202000212] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 10/05/2020] [Accepted: 10/06/2020] [Indexed: 01/23/2023]
Abstract
Autophagy functions in both selective and non-selective ways to maintain cellular homeostasis. Endoplasmic reticulum autophagy (ER-phagy) is a subclass of autophagy responsible for the degradation of the endoplasmic reticulum through selective encapsulation into autophagosomes. ER-phagy occurs both under physiological conditions and in response to stress cues, and plays a crucial role in maintaining the homeostatic control of the organelle. Although specific receptors that target parts of the ER membrane, as well as, internal proteins for lysosomal degradation have been identified, the molecular regulation of ER-phagy has been elusive. Recent work has uncovered novel regulators of ER-phagy that involve post-translational modifications of ER-resident proteins and functional cross-talk with other cellular processes. Herein, we discuss how morphology affects the function of the peripheral ER, and how ER-phagy modulates the turnover of this organelle. We also address how ER-phagy is regulated at the molecular level, considering implications relevant to human diseases.
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Affiliation(s)
- Mohamed A Eldeeb
- McGill Parkinson Program, Neurodegenerative Diseases Group, Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Cornelia E Zorca
- McGill Parkinson Program, Neurodegenerative Diseases Group, Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Mohamed A Ragheb
- Chemistry Department (Biochemistry Division), Faculty of Science, Cairo University, Giza, Egypt
| | - Fatma B Rashidi
- Chemistry Department (Biochemistry Division), Faculty of Science, Cairo University, Giza, Egypt
| | - Doaa S Salah El-Din
- Chemistry Department (Biochemistry Division), Faculty of Science, Cairo University, Giza, Egypt
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19
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Eldeeb MA, Ragheb MA. N-degron-mediated degradation and regulation of mitochondrial PINK1 kinase. Curr Genet 2020; 66:693-701. [PMID: 32157382 DOI: 10.1007/s00294-020-01062-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2020] [Revised: 02/04/2020] [Accepted: 02/05/2020] [Indexed: 12/12/2022]
Abstract
Parkinson's disease (PD) is a progressive neurodegenerative condition characterized by a gradual loss of a specific group of dopaminergic neurons in the substantia nigra. Importantly, current treatments only address the symptoms of PD, yet not the underlying molecular causes. Concomitantly, the function of genes that cause inherited forms of PD point to mitochondrial dysfunction as a major contributor in the etiology of PD. An inherent challenge that mitochondria face is the continuous exposure to diverse stresses including high levels of reactive oxygen species and protein misfolding, which increase their likelihood of dysregulation. In response, eukaryotic cells have evolved sophisticated quality control mechanisms to identify, repair and/or eliminate abnormal dysfunctional mitochondria. One such mechanism is mitophagy, a process which involves PTEN-induced putative kinase 1 (PINK1), a mitochondrial Ser/Thr kinase and Parkin, an E3 ubiquitin ligase, each encoded by genes responsible for early-onset autosomal recessive familial PD. Over 100 loss-of-function mutations in the PTEN-induced putative kinase 1 (PINK1) gene have been reported to cause autosomal recessive early-onset PD. PINK1 acts upstream of Parkin and is essential for the mitochondrial localization and activation of Parkin. Upon mitochondrial damage, PINK1 builds up on the outer mitochondrial membrane (OMM) and mediates the activation of Parkin. Activated Parkin then ubiquitinates numerous OMM proteins, eliciting mitochondrial autophagy (mitophagy). As a result, damaged mitochondrial components can be selectively eliminated. Thus, PINK1 acts a sensor of damage via fine-tuning of its levels on mitochondria, where it activates Parkin to orchestrate the clearance of unhealthy mitochondria. Previous work has unveiled that the Arg-N-end rule degradation pathway (Arg-N-degron pathway) mediates the degradation of PINK1, and thus fine-tune PINK1-dependent mitochondrial quality control pathway. Herein, we briefly discuss the interconnection between N-end rule degradation pathways and mitophagy in the context of N-degron mediated degradation of mitochondrial kinase PINK1 and highlight some of the future prospects.
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20
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Eldeeb MA, Ragheb MA, Esmaili M, Hussein F. Physiological State Dictates the Proteasomal-Mediated Purging of Misfolded Protein Fragments. Protein Pept Lett 2019; 27:251-255. [PMID: 31738130 DOI: 10.2174/0929866526666191026111951] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 09/03/2019] [Accepted: 09/04/2019] [Indexed: 01/01/2023]
Abstract
A pivotal feature that underlies the development of neurodegeneration is the accumulation of protein aggregates. In response, eukaryotic cells have evolved sophisticated quality control mechanisms to identify, repair and/or eliminate the misfolded abnormal proteins. Chaperones identify any otherwise abnormal conformations in proteins and often help them to regain their correct conformation. However, if repair is not an option, the abnormal protein is selectively degraded to prevent its oligomerization into toxic multimeric complexes. Autophagiclysosomal system and the ubiquitin-proteasome system mediate the targeted degradation of the aberrant protein fragments. Despite the increasing understanding of the molecular counteracting responses toward the accumulation of dysfunctional misfolded proteins, the molecular links between the upstream physiological inputs and the clearance of abnormal misfolded proteins is relatively poorly understood. Recent work has demonstrated that certain physiological states such as vigorous exercise and fasting may enhance the ability of mammalian cells to clear misfolded, toxic and aberrant protein fragments. These findings unveil a novel mechanism that activates the cells' protein-disposal machinery, facilitating the adaptation process of cellular proteome to fluctuations in cellular demands and alterations of environmental cues. Herein, we briefly discuss the molecular interconnection between certain physiological cues and proteasomal degradation pathway in the context of these interesting findings and highlight some of the future prospects.
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Affiliation(s)
- Mohamed A Eldeeb
- Department of Chemistry (Biochemistry Division), Faculty of Science, Cairo University, Giza 12613, Egypt.,Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | - Mohamed A Ragheb
- Department of Chemistry (Biochemistry Division), Faculty of Science, Cairo University, Giza 12613, Egypt
| | - Mansoore Esmaili
- Department of Biochemistry, University of Alberta, Edmonton, AB, Canada
| | - Faraz Hussein
- Department of Biochemistry, University of Alberta, Edmonton, AB, Canada
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21
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Tran A. The N-end rule pathway and Ubr1 enforce protein compartmentalization via P2-encoded cellular location signals. J Cell Sci 2019; 132:jcs.231662. [PMID: 30940687 DOI: 10.1242/jcs.231662] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 03/22/2019] [Indexed: 12/24/2022] Open
Abstract
The Arg/N-end rule pathway and Ubr1, a ubiquitin E3 ligase conserved from yeast to humans, is involved in the degradation of misfolded proteins in the cytosol. However, the root physiological purpose of this activity is not completely understood. Through a systematic examination of single-residue P2-position mutants of misfolded proteins, and global and targeted bioinformatic analyses of the Saccharomyces cerevisiae proteome, it was determined that Ubr1 preferentially targets mistranslocated secretory and mitochondrial proteins in the cytosol. Degradation by Ubr1 is dependent on the recognition of cellular location signals that are naturally embedded into the second amino acid residue of most proteins. This P2-encoded location signaling mechanism may shed light on how Ubr1 and the N-end rule pathway are involved in neurodegenerative diseases such as Alzheimer's and Parkinson's diseases. A corollary to this discovery is that the N-end rule pathway enforces the compartmentalization of secretory and mitochondrial proteins by degrading those that fail to reach their intended subcellular locations. The N-end rule pathway is therefore likely to have been critical to the evolution of endosymbiotic relationships that paved the way for advanced eukaryotic cellular life. This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Anthony Tran
- National University of Singapore, Department of Biological Sciences, Singapore 117604
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22
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Montandon C, Dougan DA, van Wijk KJ. N-degron specificity of chloroplast ClpS1 in plants. FEBS Lett 2019; 593:962-970. [PMID: 30953344 DOI: 10.1002/1873-3468.13378] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 03/29/2019] [Accepted: 04/01/2019] [Indexed: 12/29/2022]
Abstract
The prokaryotic N-degron pathway depends on the Clp chaperone-protease system and the ClpS adaptor for recognition of N-degron bearing substrates. Plant chloroplasts contain a diversified Clp protease, including the ClpS homolog ClpS1. Several candidate ClpS1 substrates have been identified, but the N-degron specificity is unclear. Here, we employed in vitro ClpS1 affinity assays using eight N-degron green fluorescence protein reporters containing either F, Y, L, W, I, or R in the N-terminal position. This demonstrated that ClpS1 has a restricted N-degron specificity, recognizing proteins bearing an N-terminal F or W, only weakly recognizing L, but not recognizing Y or I. This affinity is dependent on two conserved residues in the ClpS1 binding pocket and is sensitive to FR dipeptide competition, suggesting a unique chloroplast N-degron pathway.
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Affiliation(s)
- Cyrille Montandon
- Plant Biology Section, School of Integrative Plant Sciences (SIPS), Cornell University, Ithaca, NY, USA
| | - David A Dougan
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Australia
| | - Klaas J van Wijk
- Plant Biology Section, School of Integrative Plant Sciences (SIPS), Cornell University, Ithaca, NY, USA
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23
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Dissmeyer N, Rivas S, Graciet E. Life and death of proteins after protease cleavage: protein degradation by the N-end rule pathway. New Phytol 2018; 218:929-935. [PMID: 28581033 DOI: 10.1111/nph.14619] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 04/04/2017] [Indexed: 06/07/2023]
Abstract
UNLABELLED Contents Summary 929 I. INTRODUCTION conservation and diversity of N-end rule pathways 929 II. Defensive functions of the N-end rule pathway in plants 930 III. Proteases and degradation by the N-end rule pathway 930 IV. New proteomics approaches for the identification of N-end rule substrates 932 V. Concluding remarks 932 Acknowledgements 934 References 934 SUMMARY: The N-end rule relates the stability of a protein to the identity of its N-terminal residue and some of its modifications. Since its discovery in the 1980s, the repertoire of N-terminal degradation signals has expanded, leading to a diversity of N-end rule pathways. Although some of these newly discovered N-end rule pathways remain largely unexplored in plants, recent discoveries have highlighted roles of N-end rule-mediated protein degradation in plant defense against pathogens and in cell proliferation during organ growth. Despite this progress, a bottleneck remains the proteome-wide identification of N-end rule substrates due to the prerequisite for endoproteolytic cleavage and technical limitations. Here, we discuss the recent diversification of N-end rule pathways and their newly discovered functions in plant defenses, stressing the role of proteases. We expect that novel proteomics techniques (N-terminomics) will be essential for substrate identification. We review these methods, their limitations and future developments.
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Affiliation(s)
- Nico Dissmeyer
- Independent Junior Research Group on Protein Recognition and Degradation, Leibniz Institute of Plant Biochemistry (IPB), Weinberg 3, Halle (Saale), D-06120, Germany
- ScienceCampus Halle - Plant-based Bioeconomy, Betty-Heimann-Strasse 3, Halle (Saale), D-06120, Germany
| | - Susana Rivas
- LIPM, Université de Toulouse, INRA, CNRS, Castanet-Tolosan, 31 326, France
| | - Emmanuelle Graciet
- Department of Biology, Maynooth University, Maynooth, Co. Kildare, Ireland
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24
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Muñoz-Escobar J, Matta-Camacho E, Cho C, Kozlov G, Gehring K. Bound Waters Mediate Binding of Diverse Substrates to a Ubiquitin Ligase. Structure 2017; 25:719-729.e3. [PMID: 28392261 DOI: 10.1016/j.str.2017.03.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Revised: 02/03/2017] [Accepted: 03/09/2017] [Indexed: 11/16/2022]
Abstract
The N-end rule pathway controls the half-life of proteins based on their N-terminal residue. Positively charged type 1 N-degrons are recognized by a negatively charged pocket on the Zn finger named the UBR box. Here, we show that the UBR box is rigid, but bound water molecules in the pocket provide the structural plasticity required to bind different positively charged amino acids. Ultra-high-resolution crystal structures of arginine, histidine, and methylated arginine reveal that water molecules mediate the binding of N-degron peptides. Using a high-throughput binding assay and isothermal titration calorimetry, we demonstrate that the UBR box is able to bind methylated arginine and lysine peptides with high affinity and measure the preference for hydrophobic residues in the second position in the N-degron peptide. Finally, we show that the V122L mutation present in Johanson-Blizzard syndrome patients changes the specificity for the second position due to occlusion of the secondary pocket.
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Affiliation(s)
- Juliana Muñoz-Escobar
- Department of Biochemistry, Groupe de Recherche Axé sur la Structure des Protéines, McGill University, Montreal, QC H3G 0B1, Canada
| | - Edna Matta-Camacho
- Department of Biochemistry, Groupe de Recherche Axé sur la Structure des Protéines, McGill University, Montreal, QC H3G 0B1, Canada
| | - Cordelia Cho
- Department of Biochemistry, Groupe de Recherche Axé sur la Structure des Protéines, McGill University, Montreal, QC H3G 0B1, Canada
| | - Guennadi Kozlov
- Department of Biochemistry, Groupe de Recherche Axé sur la Structure des Protéines, McGill University, Montreal, QC H3G 0B1, Canada
| | - Kalle Gehring
- Department of Biochemistry, Groupe de Recherche Axé sur la Structure des Protéines, McGill University, Montreal, QC H3G 0B1, Canada.
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25
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Gibbs DJ, Bailey M, Tedds HM, Holdsworth MJ. From start to finish: amino-terminal protein modifications as degradation signals in plants. New Phytol 2016; 211:1188-94. [PMID: 27439310 DOI: 10.1111/nph.14105] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 06/07/2016] [Indexed: 05/23/2023]
Abstract
Contents 1188 I. 1188 II. 1189 III. 1190 IV. 1191 V. 1192 1192 References 1192 SUMMARY: The amino- (N-) terminus (Nt) of a protein can undergo a diverse array of co- and posttranslational modifications. Many of these create degradation signals (N-degrons) that mediate protein destruction via the N-end rule pathway of ubiquitin-mediated proteolysis. In plants, the N-end rule pathway has emerged as a major system for regulated control of protein stability. Nt-arginylation-dependent degradation regulates multiple growth, development and stress responses, and recently identified functions of Nt-acetylation can also be linked to effects on the in vivo half-lives of Nt-acetylated proteins. There is also increasing evidence that N-termini could act as important protein stability determinants in plastids. Here we review recent advances in our understanding of the relationship between the nature of protein N-termini, Nt-processing events and proteolysis in plants.
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Affiliation(s)
- Daniel J Gibbs
- School of Biosciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Mark Bailey
- School of Biosciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Hannah M Tedds
- School of Biosciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Michael J Holdsworth
- Division of Plant and Crop Sciences, School of Biosciences, University of Nottingham, Sutton Bonington, LE12 5RD, UK
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26
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AhYoung AP, Koehl A, Vizcarra CL, Cascio D, Egea PF. Structure of a putative ClpS N-end rule adaptor protein from the malaria pathogen Plasmodium falciparum. Protein Sci 2016; 25:689-701. [PMID: 26701219 DOI: 10.1002/pro.2868] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Revised: 12/20/2015] [Accepted: 12/21/2015] [Indexed: 01/05/2023]
Abstract
The N-end rule pathway uses an evolutionarily conserved mechanism in bacteria and eukaryotes that marks proteins for degradation by ATP-dependent chaperones and proteases such as the Clp chaperones and proteases. Specific N-terminal amino acids (N-degrons) are sufficient to target substrates for degradation. In bacteria, the ClpS adaptor binds and delivers N-end rule substrates for their degradation upon association with the ClpA/P chaperone/protease. Here, we report the first crystal structure, solved at 2.7 Å resolution, of a eukaryotic homolog of bacterial ClpS from the malaria apicomplexan parasite Plasmodium falciparum (Pfal). Despite limited sequence identity, Plasmodium ClpS is very similar to bacterial ClpS. Akin to its bacterial orthologs, plasmodial ClpS harbors a preformed hydrophobic pocket whose geometry and chemical properties are compatible with the binding of N-degrons. However, while the N-degron binding pocket in bacterial ClpS structures is open and accessible, the corresponding pocket in Plasmodium ClpS is occluded by a conserved surface loop that acts as a latch. Despite the closed conformation observed in the crystal, we show that, in solution, Pfal-ClpS binds and discriminates peptides mimicking bona fide N-end rule substrates. The presence of an apicoplast targeting peptide suggests that Pfal-ClpS localizes to this plastid-like organelle characteristic of all Apicomplexa and hosting most of its Clp machinery. By analogy with the related ClpS1 from plant chloroplasts and cyanobacteria, Plasmodium ClpS likely functions in association with ClpC in the apicoplast. Our findings open new venues for the design of novel anti-malarial drugs aimed at disrupting parasite-specific protein quality control pathways.
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Affiliation(s)
- Andrew P AhYoung
- Department of Biological Chemistry, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California
| | - Antoine Koehl
- Department of Biological Chemistry, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California
| | - Christina L Vizcarra
- Department of Chemistry and Biochemistry, University of California at Los Angeles, Los Angeles, California
| | - Duilio Cascio
- Department of Energy Institute for Genomics and Proteomics, University of California at Los Angeles, Los Angeles, California
| | - Pascal F Egea
- Department of Biological Chemistry, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California.,Molecular Biology Institute, University of California at Los Angeles, Los Angeles, California
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