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Swarnkar A, Leidner F, Rout AK, Ainatzi S, Schmidt CC, Becker S, Urlaub H, Griesinger C, Grubmüller H, Stein A. Determinants of chemoselectivity in ubiquitination by the J2 family of ubiquitin-conjugating enzymes. EMBO J 2024; 43:6705-6739. [PMID: 39533056 PMCID: PMC11649903 DOI: 10.1038/s44318-024-00301-3] [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: 05/10/2024] [Revised: 10/29/2024] [Accepted: 10/31/2024] [Indexed: 11/16/2024] Open
Abstract
Ubiquitin-conjugating enzymes (E2) play a crucial role in the attachment of ubiquitin to proteins. Together with ubiquitin ligases (E3), they catalyze the transfer of ubiquitin (Ub) onto lysines with high chemoselectivity. A subfamily of E2s, including yeast Ubc6 and human Ube2J2, also mediates noncanonical modification of serines, but the structural determinants for this chemical versatility remain unknown. Using a combination of X-ray crystallography, molecular dynamics (MD) simulations, and reconstitution approaches, we have uncovered a two-layered mechanism that underlies this unique reactivity. A rearrangement of the Ubc6/Ube2J2 active site enhances the reactivity of the E2-Ub thioester, facilitating attack by weaker nucleophiles. Moreover, a conserved histidine in Ubc6/Ube2J2 activates a substrate serine by general base catalysis. Binding of RING-type E3 ligases further increases the serine selectivity inherent to Ubc6/Ube2J2, via an allosteric mechanism that requires specific positioning of the ubiquitin tail at the E2 active site. Our results elucidate how subtle structural modifications to the highly conserved E2 fold yield distinct enzymatic activity.
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Affiliation(s)
- Anuruti Swarnkar
- Research Group Membrane Protein Biochemistry, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077, Göttingen, Germany
| | - Florian Leidner
- Department of Theoretical and Computational Biophysics, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077, Göttingen, Germany
| | - Ashok K Rout
- Department of NMR-based Structural Biology, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077, Göttingen, Germany
- Institut für Chemie und Metabolomics, Universität zu Lübeck, 23562, Lübeck, Germany
| | - Sofia Ainatzi
- Research Group Bioanalytical Mass Spectrometry, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077, Göttingen, Germany
| | - Claudia C Schmidt
- Research Group Membrane Protein Biochemistry, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077, Göttingen, Germany
- ETH Zürich, Otto-Stern-Weg 3, 8093, Zürich, Switzerland
| | - Stefan Becker
- Department of NMR-based Structural Biology, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077, Göttingen, Germany
| | - Henning Urlaub
- Research Group Bioanalytical Mass Spectrometry, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077, Göttingen, Germany
| | - Christian Griesinger
- Department of NMR-based Structural Biology, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077, Göttingen, Germany
| | - Helmut Grubmüller
- Department of Theoretical and Computational Biophysics, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077, Göttingen, Germany
| | - Alexander Stein
- Research Group Membrane Protein Biochemistry, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077, Göttingen, Germany.
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2
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Behera A, Sachan D, Barik GK, Reddy ABM. Role of MARCH E3 ubiquitin ligases in cancer development. Cancer Metastasis Rev 2024; 43:1257-1277. [PMID: 39037545 DOI: 10.1007/s10555-024-10201-x] [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: 04/14/2024] [Accepted: 07/14/2024] [Indexed: 07/23/2024]
Abstract
Membrane-associated RING-CH (MARCH) E3 ubiquitin ligases, a family of RING-type E3 ubiquitin ligases, have garnered increased attention for their indispensable roles in immune regulation, inflammation, mitochondrial dynamics, and lipid metabolism. The MARCH E3 ligase family consists of eleven distinct members, and the dysregulation of many of these members has been documented in several human malignancies. Over the past two decades, extensive research has revealed that MARCH E3 ligases play pivotal roles in cancer progression by ubiquitinating key oncogenes and tumor suppressors and orchestrating various signaling pathways. Some MARCH E3s act as oncogenes, while others act as tumor suppressors, and the majority of MARCH E3s play both oncogenic and tumor suppressive roles in a context-dependent manner. Notably, there is special emphasis on the sole mitochondrial MARCH E3 ligase MARCH5, which regulates mitochondrial homeostasis within cancer cells. In this review, we delve into the diverse functions of MARCH E3 ligases across different cancer types, shedding light on the underlying molecular mechanisms mediating their effects, their regulatory effects on cancer and their potential as therapeutic targets.
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Affiliation(s)
- Abhayananda Behera
- Department of Animal Biology, School of Life Sciences, University of Hyderabad, Hyderabad, 500046, India
| | - Deepanshi Sachan
- Department of Animal Biology, School of Life Sciences, University of Hyderabad, Hyderabad, 500046, India
| | - Ganesh Kumar Barik
- Cancer Biology Division, National Centre for Cell Science, Savitribai Phule Pune University, Ganeshkhind Road, Pune, Maharashtra, 411007, India
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3
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Fenton NM, Qian L, Paine EG, Sharpe LJ, Brown AJ. A paREDOX in the control of cholesterol biosynthesis: Does the NADPH sensor and E3 ubiquitin ligase MARCHF6 protect mammalian cells during oxidative stress by controlling sterol biosynthesis? Bioessays 2024; 46:e2400073. [PMID: 38760877 DOI: 10.1002/bies.202400073] [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: 03/27/2024] [Revised: 04/30/2024] [Accepted: 05/03/2024] [Indexed: 05/19/2024]
Abstract
Sterols and the reductant nicotinamide adenine dinucleotide phosphate (NADPH), essential for eukaryotic life, arose because of, and as an adaptation to, rising levels of molecular oxygen (O2). Hence, the NADPH and O2-intensive process of sterol biosynthesis is inextricably linked to redox status. In mammals, cholesterol biosynthesis is exquisitely regulated post-translationally by multiple E3 ubiquitin ligases, with membrane associated Really Interesting New Gene (RING) C3HC4 finger 6 (MARCHF6) degrading at least six enzymes in the pathway. Intriguingly, all these MARCHF6-dependent enzymes require NADPH. Moreover, MARCHF6 is activated by NADPH, although what this means for control of cholesterol synthesis is unclear. Indeed, this presents a paradox for how NADPH regulates this vital pathway, since NADPH is a cofactor in cholesterol biosynthesis and yet, low levels of NADPH should spare cholesterol biosynthesis enzymes targeted by MARCHF6 by reducing its activity. We speculate MARCHF6 helps mammalian cells adapt to oxidative stress (signified by low NADPH levels) by reducing degradation of cholesterogenic enzymes, thereby maintaining synthesis of protective cholesterol.
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Affiliation(s)
- Nicole M Fenton
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Lydia Qian
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Eloise G Paine
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Laura J Sharpe
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Andrew J Brown
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
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4
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Zhang L, Cao Z, Hong Y, He H, Chen L, Yu Z, Gao Y. Squalene Epoxidase: Its Regulations and Links with Cancers. Int J Mol Sci 2024; 25:3874. [PMID: 38612682 PMCID: PMC11011400 DOI: 10.3390/ijms25073874] [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: 01/09/2024] [Revised: 03/09/2024] [Accepted: 03/19/2024] [Indexed: 04/14/2024] Open
Abstract
Squalene epoxidase (SQLE) is a key enzyme in the mevalonate-cholesterol pathway that plays a critical role in cellular physiological processes. It converts squalene to 2,3-epoxysqualene and catalyzes the first oxygenation step in the pathway. Recently, intensive efforts have been made to extend the current knowledge of SQLE in cancers through functional and mechanistic studies. However, the underlying mechanisms and the role of SQLE in cancers have not been fully elucidated yet. In this review, we retrospected current knowledge of SQLE as a rate-limiting enzyme in the mevalonate-cholesterol pathway, while shedding light on its potential as a diagnostic and prognostic marker, and revealed its therapeutic values in cancers. We showed that SQLE is regulated at different levels and is involved in the crosstalk with iron-dependent cell death. Particularly, we systemically reviewed the research findings on the role of SQLE in different cancers. Finally, we discussed the therapeutic implications of SQLE inhibitors and summarized their potential clinical values. Overall, this review discussed the multifaceted mechanisms that involve SQLE to present a vivid panorama of SQLE in cancers.
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Affiliation(s)
- Lin Zhang
- Department of Thoracic Surgery, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital & Shenzhen Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Shenzhen 518116, China
| | - Zheng Cao
- Department of Pathology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China
| | - Yuheng Hong
- Department of Thoracic Surgery, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China
| | - Haihua He
- Department of Thoracic Surgery, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China
- Department of Oncology, Renmin Hospital of Wuhan University, Wuhan 430060, China
| | - Leifeng Chen
- Department of Thoracic Surgery, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China
- Department of Oncology, Renmin Hospital of Wuhan University, Wuhan 430060, China
| | - Zhentao Yu
- Department of Thoracic Surgery, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital & Shenzhen Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Shenzhen 518116, China
| | - Yibo Gao
- Central Laboratory & Shenzhen Key Laboratory of Epigenetics and Precision Medicine for Cancers, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital & Shenzhen Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Shenzhen 518116, China
- State Key Laboratory of Molecular Oncology, National Cancer Center, National Clinical Research Center for Cancer, Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China
- Laboratory of Translational Medicine, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China
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5
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Wu K, Itskanov S, Lynch DL, Chen Y, Turner A, Gumbart JC, Park E. Substrate recognition mechanism of the endoplasmic reticulum-associated ubiquitin ligase Doa10. Nat Commun 2024; 15:2182. [PMID: 38467638 PMCID: PMC10928120 DOI: 10.1038/s41467-024-46409-2] [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: 08/26/2023] [Accepted: 02/14/2024] [Indexed: 03/13/2024] Open
Abstract
Doa10 (MARCHF6 in metazoans) is a large polytopic membrane-embedded E3 ubiquitin ligase in the endoplasmic reticulum (ER) that plays an important role in quality control of cytosolic and ER proteins. Although Doa10 is highly conserved across eukaryotes, it is not understood how Doa10 recognizes its substrates. Here, we define the substrate recognition mechanism of Doa10 by structural and functional analyses on Saccharomyces cerevisiae Doa10 and its model substrates. Cryo-EM analysis shows that Doa10 has unusual architecture with a large lipid-filled central cavity, and its conserved middle domain forms an additional water-filled lateral tunnel open to the cytosol. Our biochemical data and molecular dynamics simulations suggest that the entrance of the substrate's degron peptide into the lateral tunnel is required for efficient polyubiquitination. The N- and C-terminal membrane domains of Doa10 seem to form fence-like features to restrict polyubiquitination to those proteins that can access the central cavity and lateral tunnel. Our study reveals how extended hydrophobic sequences at the termini of substrate proteins are recognized by Doa10 as a signal for quality control.
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Affiliation(s)
- Kevin Wu
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, 94720, USA
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA, 94720, USA
| | - Samuel Itskanov
- Biophysics Graduate Program, University of California, Berkeley, CA, 94720, USA
| | - Diane L Lynch
- School of Physics and School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Yuanyuan Chen
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, 94720, USA
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA, 94720, USA
| | - Aasha Turner
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, 94720, USA
| | - James C Gumbart
- School of Physics and School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Eunyong Park
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, 94720, USA.
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA, 94720, USA.
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6
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Wu K, Itskanov S, Lynch DL, Chen Y, Turner A, Gumbart JC, Park E. Substrate recognition mechanism of the endoplasmic reticulum-associated ubiquitin ligase Doa10. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.09.574907. [PMID: 38260251 PMCID: PMC10802466 DOI: 10.1101/2024.01.09.574907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Doa10 (MARCH6 in metazoans) is a large polytopic membrane-embedded E3 ubiquitin ligase in the endoplasmic reticulum (ER) that plays an important role in quality control of cytosolic and ER proteins. Although Doa10 is highly conserved across eukaryotes, it is not understood how Doa10 recognizes its substrates. Here, we defined the substrate recognition mechanism of Doa10 by structural and functional analyses on Saccharomyces cerevisiae Doa10 and its well-defined degron Deg1. Cryo-EM analysis shows that Doa10 has unusual architecture with a large lipid-filled central cavity, and its conserved middle domain forms an additional water-filled lateral tunnel open to the cytosol. Our biochemical data and molecular dynamics simulations suggest that the entrance of the substrate's degron peptide into the lateral tunnel is required for efficient polyubiquitination. The N- and C-terminal membrane domains of Doa10 seem to form fence-like features to restrict polyubiquitination to those proteins that can access the central cavity and lateral tunnel.
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Affiliation(s)
- Kevin Wu
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA 94720, USA
| | - Samuel Itskanov
- Biophysics Graduate Program, University of California, Berkeley, CA 94720, USA
| | - Diane L. Lynch
- School of Physics and School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Yuanyuan Chen
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA 94720, USA
| | - Aasha Turner
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA
| | - James C. Gumbart
- School of Physics and School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Eunyong Park
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA 94720, USA
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7
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Botsch JJ, Junker R, Sorgenfrei M, Ogger PP, Stier L, von Gronau S, Murray PJ, Seeger MA, Schulman BA, Bräuning B. Doa10/MARCH6 architecture interconnects E3 ligase activity with lipid-binding transmembrane channel to regulate SQLE. Nat Commun 2024; 15:410. [PMID: 38195637 PMCID: PMC10776854 DOI: 10.1038/s41467-023-44670-5] [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: 06/12/2023] [Accepted: 12/19/2023] [Indexed: 01/11/2024] Open
Abstract
Transmembrane E3 ligases play crucial roles in homeostasis. Much protein and organelle quality control, and metabolic regulation, are determined by ER-resident MARCH6 E3 ligases, including Doa10 in yeast. Here, we present Doa10/MARCH6 structural analysis by cryo-EM and AlphaFold predictions, and a structure-based mutagenesis campaign. The majority of Doa10/MARCH6 adopts a unique circular structure within the membrane. This channel is established by a lipid-binding scaffold, and gated by a flexible helical bundle. The ubiquitylation active site is positioned over the channel by connections between the cytosolic E3 ligase RING domain and the membrane-spanning scaffold and gate. Here, by assaying 95 MARCH6 variants for effects on stability of the well-characterized substrate SQLE, which regulates cholesterol levels, we reveal crucial roles of the gated channel and RING domain consistent with AlphaFold-models of substrate-engaged and ubiquitylation complexes. SQLE degradation further depends on connections between the channel and RING domain, and lipid binding sites, revealing how interconnected Doa10/MARCH6 elements could orchestrate metabolic signals, substrate binding, and E3 ligase activity.
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Affiliation(s)
- J Josephine Botsch
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152, Martinsried, Germany
- Technical University of Munich, School of Natural Sciences, Munich, Germany
| | - Roswitha Junker
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152, Martinsried, Germany
| | - Michèle Sorgenfrei
- Institute of Medical Microbiology, University of Zurich, Gloriastrasse 28/30, 8006, Zurich, Switzerland
| | - Patricia P Ogger
- Research Group of Immunoregulation, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152, Martinsried, Germany
| | - Luca Stier
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152, Martinsried, Germany
- Technical University of Munich, School of Natural Sciences, Munich, Germany
| | - Susanne von Gronau
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152, Martinsried, Germany
| | - Peter J Murray
- Research Group of Immunoregulation, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152, Martinsried, Germany
| | - Markus A Seeger
- Institute of Medical Microbiology, University of Zurich, Gloriastrasse 28/30, 8006, Zurich, Switzerland
| | - Brenda A Schulman
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152, Martinsried, Germany.
| | - Bastian Bräuning
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152, Martinsried, Germany.
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Christianson JC, Jarosch E, Sommer T. Mechanisms of substrate processing during ER-associated protein degradation. Nat Rev Mol Cell Biol 2023; 24:777-796. [PMID: 37528230 DOI: 10.1038/s41580-023-00633-8] [Citation(s) in RCA: 67] [Impact Index Per Article: 33.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/20/2023] [Indexed: 08/03/2023]
Abstract
Maintaining proteome integrity is essential for long-term viability of all organisms and is overseen by intrinsic quality control mechanisms. The secretory pathway of eukaryotes poses a challenge for such quality assurance as proteins destined for secretion enter the endoplasmic reticulum (ER) and become spatially segregated from the cytosolic machinery responsible for disposal of aberrant (misfolded or otherwise damaged) or superfluous polypeptides. The elegant solution provided by evolution is ER-membrane-bound ubiquitylation machinery that recognizes misfolded or surplus proteins or by-products of protein biosynthesis in the ER and delivers them to 26S proteasomes for degradation. ER-associated protein degradation (ERAD) collectively describes this specialized arm of protein quality control via the ubiquitin-proteasome system. But, instead of providing a single strategy to remove defective or unwanted proteins, ERAD represents a collection of independent processes that exhibit distinct yet overlapping selectivity for a wide range of substrates. Not surprisingly, ER-membrane-embedded ubiquitin ligases (ER-E3s) act as central hubs for each of these separate ERAD disposal routes. In these processes, ER-E3s cooperate with a plethora of specialized factors, coordinating recognition, transport and ubiquitylation of undesirable secretory, membrane and cytoplasmic proteins. In this Review, we focus on substrate processing during ERAD, highlighting common threads as well as differences between the many routes via ERAD.
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Affiliation(s)
- John C Christianson
- Botnar Research Centre, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, UK.
| | - Ernst Jarosch
- Max-Delbrück-Centrer for Molecular Medicine in Helmholtz Association, Berlin-Buch, Germany
| | - Thomas Sommer
- Max-Delbrück-Centrer for Molecular Medicine in Helmholtz Association, Berlin-Buch, Germany.
- Institute for Biology, Humboldt Universität zu Berlin, Berlin, Germany.
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9
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Lu Z, Shen Q, Liu L, Talbo G, Speight R, Trau M, Dumsday G, Howard CB, Vickers CE, Peng B. Profiling proteomic responses to hexokinase-II depletion in terpene-producing Saccharomyces cerevisiae. ENGINEERING MICROBIOLOGY 2023; 3:100079. [PMID: 39628925 PMCID: PMC11610997 DOI: 10.1016/j.engmic.2023.100079] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 01/03/2023] [Accepted: 02/13/2023] [Indexed: 12/06/2024]
Abstract
Hexokinase II (Hxk2) is a master protein in glucose-mediated transcriptional repression signaling pathway. Degrading Hxk2 through an auxin-inducible protein degradation previously doubled sesquiterpene (nerolidol) production at gram-per-liter levels in Saccharomyces cerevisiae. Global transcriptomics/proteomics profiles in Hxk2-deficient background are important to understanding genetic and molecular mechanisms for improved nerolidol production and guiding further strain optimization. Here, proteomic responses to Hxk2 depletion are investigated in the yeast strains harboring a GAL promoters-controlled nerolidol synthetic pathway, at the exponential and ethanol growth phases and in GAL80-wildtype and gal80Δ backgrounds. Carbon metabolic pathways and amino acid metabolic pathways show diversified responses to Hxk2 depletion and growth on ethanol, including upregulation of alternative carbon catabolism and respiration as well as downregulation of amino acid synthesis. De-repression of GAL genes may contribute to improved nerolidol production in Hxk2-depleted strains. Seventeen transcription factors associated with upregulated genes are enriched. Validating Ash1-mediated repression on the RIM4 promoter shows the variation on the regulatory effects of different Ash1-binding sites and the synergistic effect of Ash1 and Hxk2-mediated repression. Further validation of individual promoters shows that HXT1 promoter activities are glucose-dependent in hxk2Δ background, but much weaker than those in HXK2-wildtype background. In summary, inactivating HXK2 may relieve glucose repression on respiration and GAL promoters for improved bioproduction under aerobic conditions in S. cerevisiae. The proteomics profiles provide a better genetics overview for a better metabolic engineering design in Hxk2-deficient backgrounds.
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Affiliation(s)
- Zeyu Lu
- ARC Centre of Excellence in Synthetic Biology, Queensland University of Technology, Brisbane, QLD, 4000, Australia
- Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, Brisbane, QLD, 4072, Australia
- Centre of Agriculture and the Bioeconomy, School of Biology and Environmental Science, Faculty of Science, Queensland University of Technology, Brisbane, QLD, 4000, Australia
- CSIRO Synthetic Biology Future Science Platform, Commonwealth Scientific and Industrial Research Organisation (CSIRO), Black Mountain, ACT, 2601, Australia
| | - Qianyi Shen
- ARC Centre of Excellence in Synthetic Biology, Queensland University of Technology, Brisbane, QLD, 4000, Australia
- Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, Brisbane, QLD, 4072, Australia
- Centre of Agriculture and the Bioeconomy, School of Biology and Environmental Science, Faculty of Science, Queensland University of Technology, Brisbane, QLD, 4000, Australia
- School of Chemistry and Molecular Biosciences (SCMB), the University of Queensland, Brisbane, QLD, 4072, Australia
| | - Lian Liu
- Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, Brisbane, QLD, 4072, Australia
- Metabolomics Australia (Queensland Node), Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Gert Talbo
- Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, Brisbane, QLD, 4072, Australia
- Metabolomics Australia (Queensland Node), Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Robert Speight
- ARC Centre of Excellence in Synthetic Biology, Queensland University of Technology, Brisbane, QLD, 4000, Australia
- Centre of Agriculture and the Bioeconomy, School of Biology and Environmental Science, Faculty of Science, Queensland University of Technology, Brisbane, QLD, 4000, Australia
| | - Matt Trau
- Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, Brisbane, QLD, 4072, Australia
- School of Chemistry and Molecular Biosciences (SCMB), the University of Queensland, Brisbane, QLD, 4072, Australia
| | | | - Christopher B. Howard
- Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Claudia E. Vickers
- ARC Centre of Excellence in Synthetic Biology, Queensland University of Technology, Brisbane, QLD, 4000, Australia
- Centre of Agriculture and the Bioeconomy, School of Biology and Environmental Science, Faculty of Science, Queensland University of Technology, Brisbane, QLD, 4000, Australia
- CSIRO Synthetic Biology Future Science Platform, Commonwealth Scientific and Industrial Research Organisation (CSIRO), Black Mountain, ACT, 2601, Australia
- Eden Brew Pty Ltd, Glenorie, NSW, 2157, Australia
| | - Bingyin Peng
- ARC Centre of Excellence in Synthetic Biology, Queensland University of Technology, Brisbane, QLD, 4000, Australia
- Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, Brisbane, QLD, 4072, Australia
- Centre of Agriculture and the Bioeconomy, School of Biology and Environmental Science, Faculty of Science, Queensland University of Technology, Brisbane, QLD, 4000, Australia
- CSIRO Synthetic Biology Future Science Platform, Commonwealth Scientific and Industrial Research Organisation (CSIRO), Black Mountain, ACT, 2601, Australia
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10
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Doss EM, Moore JM, Harman BH, Doud EH, Rubenstein EM, Bernstein DA. Characterization of endoplasmic reticulum-associated degradation in the human fungal pathogen Candida albicans. PeerJ 2023; 11:e15897. [PMID: 37645016 PMCID: PMC10461541 DOI: 10.7717/peerj.15897] [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: 05/22/2023] [Accepted: 07/24/2023] [Indexed: 08/31/2023] Open
Abstract
Background Candida albicans is the most prevalent human fungal pathogen. In immunocompromised individuals, C. albicans can cause serious systemic disease, and patients infected with drug-resistant isolates have few treatment options. The ubiquitin-proteasome system has not been thoroughly characterized in C. albicans. Research from other organisms has shown ubiquitination is important for protein quality control and regulated protein degradation at the endoplasmic reticulum (ER) via ER-associated protein degradation (ERAD). Methods Here we perform the first characterization, to our knowledge, of ERAD in a human fungal pathogen. We generated functional knockouts of C. albicans genes encoding three proteins predicted to play roles in ERAD, the ubiquitin ligases Hrd1 and Doa10 and the ubiquitin-conjugating enzyme Ubc7. We assessed the fitness of each mutant in the presence of proteotoxic stress, and we used quantitative tandem mass tag mass spectrometry to characterize proteomic alterations in yeast lacking each gene. Results Consistent with a role in protein quality control, yeast lacking proteins thought to contribute to ERAD displayed hypersensitivity to proteotoxic stress. Furthermore, each mutant displayed distinct proteomic profiles, revealing potential physiological ERAD substrates, co-factors, and compensatory stress response factors. Among candidate ERAD substrates are enzymes contributing to ergosterol synthesis, a known therapeutic vulnerability of C. albicans. Together, our results provide the first description of ERAD function in C. albicans, and, to our knowledge, any pathogenic fungus.
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Affiliation(s)
- Ellen M. Doss
- Department of Biology, Ball State University, Muncie, Indiana, United States
- Mode of Action and Resistance Management Center of Expertise, Corteva Agriscience, Indianapolis, Indiana, United States
| | - Joshua M. Moore
- Department of Biology, Ball State University, Muncie, Indiana, United States
| | - Bryce H. Harman
- Department of Biology, Ball State University, Muncie, Indiana, United States
| | - Emma H. Doud
- Center for Proteome Analysis, Indiana University School of Medicine, Indianapolis, Indiana, United States
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, United States
| | - Eric M. Rubenstein
- Department of Biology, Ball State University, Muncie, Indiana, United States
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11
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Qian L, Scott NA, Capell-Hattam IM, Draper EA, Fenton NM, Luu W, Sharpe LJ, Brown AJ. Cholesterol synthesis enzyme SC4MOL is fine-tuned by sterols and targeted for degradation by the E3 ligase MARCHF6. J Lipid Res 2023; 64:100362. [PMID: 36958722 PMCID: PMC10176258 DOI: 10.1016/j.jlr.2023.100362] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 02/09/2023] [Accepted: 02/25/2023] [Indexed: 03/25/2023] Open
Abstract
Cholesterol biosynthesis is a highly regulated pathway, with over 20 enzymes controlled at the transcriptional and post-translational level. Whilst some enzymes remain stable, increased sterol levels can trigger degradation of several synthesis enzymes via the ubiquitin-proteasome system. Of note, we previously identified four cholesterol synthesis enzymes as substrates for one E3 ubiquitin ligase, membrane-associated RING-CH-type finger 6 (MARCHF6). Whether MARCHF6 targets the cholesterol synthesis pathway at other points is unknown. In addition, the post-translational regulation of many cholesterol synthesis enzymes, including the C4-demethylation complex (sterol-C4-methyl oxidase-like, SC4MOL; NAD(P) dependent steroid dehydrogenase-like, NSDHL; hydroxysteroid 17-beta dehydrogenase, HSD17B7) is largely uncharacterized. Using cultured mammalian cell-lines (human-derived and Chinese Hamster Ovary cells), we show SC4MOL, the first acting enzyme of C4-demethylation, is a MARCHF6 substrate, and is rapidly turned over and sensitive to sterols. Sterol depletion stabilizes SC4MOL protein levels, whilst sterol excess downregulates both transcript and protein levels. Furthermore, we found SC4MOL depletion by siRNA results in a significant decrease in total cell cholesterol. Thus, our work indicates SC4MOL is the most regulated enzyme in the C4-demethylation complex. Our results further implicate MARCHF6 as a crucial post-translational regulator of cholesterol synthesis, with this E3 ubiquitin ligase controlling levels of at least five enzymes of the pathway.
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Affiliation(s)
- Lydia Qian
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales 2052, Australia
| | - Nicola A Scott
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales 2052, Australia
| | - Isabelle M Capell-Hattam
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales 2052, Australia
| | - Eliza A Draper
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales 2052, Australia
| | - Nicole M Fenton
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales 2052, Australia
| | - Winnie Luu
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales 2052, Australia
| | - Laura J Sharpe
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales 2052, Australia
| | - Andrew J Brown
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales 2052, Australia.
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12
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Mehrtash AB, Hochstrasser M. Ectopic RING activity at the ER membrane differentially impacts ERAD protein quality control pathways. J Biol Chem 2023; 299:102927. [PMID: 36682496 PMCID: PMC9950527 DOI: 10.1016/j.jbc.2023.102927] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Revised: 01/12/2023] [Accepted: 01/13/2023] [Indexed: 01/20/2023] Open
Abstract
Endoplasmic reticulum-associated degradation (ERAD) is a protein quality control pathway that ensures misfolded proteins are removed from the ER and destroyed. In ERAD, membrane and luminal substrates are ubiquitylated by ER-resident RING-type E3 ubiquitin ligases, retrotranslocated into the cytosol, and degraded by the proteasome. Overexpression of ERAD factors is frequently used in yeast and mammalian cells to study this process. Here, we analyze the impact of ERAD E3 overexpression on substrate turnover in yeast, where there are three ERAD E3 complexes (Doa10, Hrd1, and Asi1-3). Elevated Doa10 or Hrd1 (but not Asi1) RING activity at the ER membrane resulting from protein overexpression inhibits the degradation of specific Doa10 substrates. The ERAD E2 ubiquitin-conjugating enzyme Ubc6 becomes limiting under these conditions, and UBC6 overexpression restores Ubc6-mediated ERAD. Using a subset of the dominant-negative mutants, which contain the Doa10 RING domain but lack the E2-binding region, we show that they induce degradation of membrane tail-anchored Ubc6 independently of endogenous Doa10 and the other ERAD E3 complexes. This remains true even if the cells lack the Dfm1 rhomboid pseudoprotease, which is also a proposed retrotranslocon. Hence, rogue RING activity at the ER membrane elicits a highly specific off-pathway defect in the Doa10 pathway, and the data point to an additional ERAD E3-independent retrotranslocation mechanism.
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Affiliation(s)
- Adrian B Mehrtash
- Department of Molecular, Cellular, & Developmental Biology, Yale University, New Haven, Connecticut, USA
| | - Mark Hochstrasser
- Department of Molecular, Cellular, & Developmental Biology, Yale University, New Haven, Connecticut, USA; Department of Molecular Biophysics & Biochemistry, Yale University, New Haven, Connecticut, USA.
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13
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Depienne C, van den Maagdenberg AMJM, Kühnel T, Ishiura H, Corbett MA, Tsuji S. Insights into familial adult myoclonus epilepsy pathogenesis: How the same repeat expansion in six unrelated genes may lead to cortical excitability. Epilepsia 2023. [PMID: 36622139 DOI: 10.1111/epi.17504] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 12/22/2022] [Accepted: 01/06/2023] [Indexed: 01/10/2023]
Abstract
Familial adult myoclonus epilepsy (FAME) results from the same pathogenic TTTTA/TTTCA pentanucleotide repeat expansion in six distinct genes encoding proteins with different subcellular localizations and very different functions, which poses the issue of what causes the neurobiological disturbances that lead to the clinical phenotype. Postmortem and electrophysiological studies have pointed to cortical hyperexcitability as well as dysfunction and neurodegeneration of both the cortex and cerebellum of FAME subjects. FAME expansions, contrary to the same expansion in DAB1 causing spinocerebellar ataxia type 37, seem to have no or limited impact on their recipient gene expression, which suggests a pathophysiological mechanism independent of the gene and its function. Current hypotheses include toxicity of the RNA molecules carrying UUUCA repeats, or toxicity of polypeptides encoded by the repeats, a mechanism known as repeat-associated non-AUG translation. The analysis of postmortem brains of FAME1 expansion (in SAMD12) carriers has revealed the presence of RNA foci that could be formed by the aggregation of RNA molecules with abnormal UUUCA repeats, but evidence is still lacking for other FAME subtypes. Even when the expansion is located in a gene ubiquitously expressed, expression of repeats remains undetectable in peripheral tissues (blood, skin). Therefore, the development of appropriate cellular models (induced pluripotent stem cell-derived neurons) or the study of affected tissues in patients is required to elucidate how FAME repeat expansions located in unrelated genes lead to disease.
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Affiliation(s)
- Christel Depienne
- Institute of Human Genetics, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Arn M J M van den Maagdenberg
- Department of Human Genetics, Leiden University Medical Center, Leiden, the Netherlands.,Department of Neurology, Leiden University Medical Center, Leiden, the Netherlands
| | - Theresa Kühnel
- Institute of Human Genetics, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Hiroyuki Ishiura
- Department of Neurology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan.,Department of Neurology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Mark A Corbett
- Robinson Research Institute, University of Adelaide, Adelaide Medical School, Adelaide, South Australia, Australia
| | - Shoji Tsuji
- Department of Neurology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan.,Institute of Medical Genomics, International University of Health and Welfare, Chiba, Japan
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14
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Krshnan L, van de Weijer ML, Carvalho P. Endoplasmic Reticulum-Associated Protein Degradation. Cold Spring Harb Perspect Biol 2022; 14:a041247. [PMID: 35940909 PMCID: PMC9732900 DOI: 10.1101/cshperspect.a041247] [Citation(s) in RCA: 67] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Misfolded, potentially toxic proteins in the lumen and membrane of the endoplasmic reticulum (ER) are eliminated by proteasomes in the cytosol through ER-associated degradation (ERAD). The ERAD process involves the recognition of substrates in the lumen and membrane of the ER, their translocation into the cytosol, ubiquitination, and delivery to the proteasome for degradation. These ERAD steps are performed by membrane-embedded ubiquitin-ligase complexes of different specificity that together cover a wide range of substrates. Besides misfolded proteins, ERAD further contributes to quality control by targeting unassembled and mislocalized proteins. ERAD also targets a restricted set of folded proteins to influence critical ER functions such as sterol biosynthesis, calcium homeostasis, or ER contacts with other organelles. This review describes the ubiquitin-ligase complexes and the principles guiding protein degradation by ERAD.
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Affiliation(s)
- Logesvaran Krshnan
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, United Kingdom
| | | | - Pedro Carvalho
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, United Kingdom
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15
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Mehrtash AB, Hochstrasser M. Elements of the ERAD ubiquitin ligase Doa10 regulating sequential poly-ubiquitylation of its targets. iScience 2022; 25:105351. [PMID: 36325070 PMCID: PMC9619350 DOI: 10.1016/j.isci.2022.105351] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 08/16/2022] [Accepted: 10/11/2022] [Indexed: 11/29/2022] Open
Abstract
In ER-associated degradation (ERAD), misfolded ER proteins are degraded by the proteasome after undergoing ubiquitylation. Yeast Doa10 (human MARCHF6/TEB4) is a membrane-embedded E3 ubiquitin ligase that functions with E2s Ubc6 and Ubc7. Ubc6 attaches a single ubiquitin to substrates, which is extended by Ubc7 to form a polyubiquitin chain. We show the conserved C-terminal element (CTE) of Doa10 promotes E3-mediated Ubc6 activity. Doa10 substrates undergoing an alternative ubiquitylation mechanism are still degraded in CTE-mutant cells. Structure prediction by AlphaFold2 suggests the CTE binds near the catalytic RING-CH domain, implying a direct role in substrate ubiquitylation, and we confirm this interaction using intragenic suppression. Truncation analysis defines a minimal E2-binding region of Doa10; structural predictions suggest that Doa10 forms a retrotranslocation channel and that E2s bind within the cofactor-binding region defined here. These results provide mechanistic insight into how Doa10, and potentially other ligases, interact with their cofactors and mediate ERAD. The conserved Doa10 C-terminus promotes E3-mediated activity of Ubc6 The minimal E2-binding region of Doa10 includes TMs 1–9 The N- and C-terminus of Doa10 interact, likely forming an ERAD protein channel
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Affiliation(s)
- Adrian B. Mehrtash
- Department of Molecular, Cellular, & Developmental Biology, Yale University, New Haven, 06520 CT, USA
| | - Mark Hochstrasser
- Department of Molecular, Cellular, & Developmental Biology, Yale University, New Haven, 06520 CT, USA
- Department of Molecular Biophysics & Biochemistry, Yale University, New Haven, CT 06520, USA
- Corresponding author
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16
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The MARCHF6 E3 ubiquitin ligase acts as an NADPH sensor for the regulation of ferroptosis. Nat Cell Biol 2022; 24:1239-1251. [PMID: 35941365 DOI: 10.1038/s41556-022-00973-1] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 06/29/2022] [Indexed: 01/16/2023]
Abstract
Ferroptosis is a unique form of cell death caused by excessive iron-dependent lipid peroxidation. The level of the anabolic reductant NADPH is a biomarker of ferroptosis sensitivity. However, specific regulators that detect cellular NADPH levels, thereby modulating downstream ferroptosis cascades, are largely unknown. We show here that the transmembrane endoplasmic reticulum MARCHF6 E3 ubiquitin ligase recognizes NADPH through its C-terminal regulatory region. This interaction upregulates the E3 ligase activity of MARCHF6, thus downregulating ferroptosis. We also found that MARCHF6 mediates the degradation of the key ferroptosis effectors ACSL4 and p53. Furthermore, inhibiting ferroptosis rescued the growth of MARCHF6-deficient tumours and peri-natal lethality of Marchf6-/- mice. Together, these findings identify MARCHF6 as a previously unknown NADPH sensor in the ubiquitin system and a crucial regulator of ferroptosis.
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17
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Hill J, Nyathi Y. USP5 enhances SGTA mediated protein quality control. PLoS One 2022; 17:e0257786. [PMID: 35895711 PMCID: PMC9328565 DOI: 10.1371/journal.pone.0257786] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Accepted: 07/11/2022] [Indexed: 11/18/2022] Open
Abstract
Mislocalised membrane proteins (MLPs) present a risk to the cell due to exposed hydrophobic amino acids which cause MLPs to aggregate. Previous studies identified SGTA as a key component of the machinery that regulates the quality control of MLPs. Overexpression of SGTA promotes deubiqutination of MLPs resulting in their accumulation in cytosolic inclusions, suggesting SGTA acts in collaboration with deubiquitinating enzymes (DUBs) to exert these effects. However, the DUBs that play a role in this process have not been identified. In this study we have identified the ubiquitin specific peptidase 5 (USP5) as a DUB important in regulating the quality control of MLPs. We show that USP5 is in complex with SGTA, and this association is increased in the presence of an MLP. Overexpression of SGTA results in an increase in steady-state levels of MLPs suggesting a delay in proteasomal degradation of substrates. However, our results show that this effect is strongly dependent on the presence of USP5. We find that in the absence of USP5, the ability of SGTA to increase the steady state levels of MLPs is compromised. Moreover, knockdown of USP5 results in a reduction in the steady state levels of MLPs, while overexpression of USP5 increases the steady state levels. Our findings suggest that the interaction of SGTA with USP5 enables specific MLPs to escape proteasomal degradation allowing selective modulation of MLP quality control. These findings progress our understanding of aggregate formation, a hallmark in a range of neurodegenerative diseases and type II diabetes, as well as physiological processes of aggregate clearance.
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Affiliation(s)
- Jake Hill
- School of Life Sciences, Joseph Banks Laboratories, University of Lincoln, Lincoln, United Kingdom
- School of Chemistry and Bioscience, Faculty of Life Sciences, University of Bradford, Bradford, United Kingdom
| | - Yvonne Nyathi
- School of Life Sciences, Joseph Banks Laboratories, University of Lincoln, Lincoln, United Kingdom
- School of Chemistry and Bioscience, Faculty of Life Sciences, University of Bradford, Bradford, United Kingdom
- * E-mail:
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18
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Christianson JC, Carvalho P. Order through destruction: how ER-associated protein degradation contributes to organelle homeostasis. EMBO J 2022; 41:e109845. [PMID: 35170763 PMCID: PMC8922271 DOI: 10.15252/embj.2021109845] [Citation(s) in RCA: 74] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 01/09/2022] [Accepted: 01/25/2022] [Indexed: 12/24/2022] Open
Abstract
The endoplasmic reticulum (ER) is a large, dynamic, and multifunctional organelle. ER protein homeostasis is essential for the coordination of its diverse functions and depends on ER-associated protein degradation (ERAD). The latter process selects target proteins in the lumen and membrane of the ER, promotes their ubiquitination, and facilitates their delivery into the cytosol for degradation by the proteasome. Originally characterized for a role in the degradation of misfolded proteins and rate-limiting enzymes of sterol biosynthesis, the many branches of ERAD now appear to control the levels of a wider range of substrates and influence more broadly the organization and functions of the ER, as well as its interactions with adjacent organelles. Here, we discuss recent mechanistic advances in our understanding of ERAD and of its consequences for the regulation of ER functions.
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Affiliation(s)
- John C Christianson
- Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal SciencesBotnar Research CentreUniversity of OxfordOxfordUK
| | - Pedro Carvalho
- Sir William Dunn School of PathologyUniversity of OxfordOxfordUK
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19
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Peters L, Depienne C, Klebe S. Familial adult myoclonic epilepsy (FAME): clinical features, molecular characteristics, pathophysiological aspects and diagnostic work-up. MED GENET-BERLIN 2021; 33:311-318. [PMID: 38835431 PMCID: PMC11006339 DOI: 10.1515/medgen-2021-2100] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 11/16/2021] [Indexed: 06/06/2024]
Abstract
Familial adult myoclonic epilepsy (FAME) is a rare autosomal dominant disorder characterized by myoclonus and seizures. The genetic variant underlying FAME is an intronic repeat expansion composed of two different pentamers: an expanded TTTTA, which is the motif originally present at the locus, and an insertion of TTTCA repeats, which is usually located at the 3' end and likely corresponds to the pathogenic part of the expansion. This repeat expansion has been identified so far in six genes located on different chromosomes, which remarkably encode proteins with distinct cellular localizations and functions. Although the exact pathophysiological mechanisms remain to be clarified, it is likely that FAME repeat expansions lead to disease independently of the gene where they occur. We herein review the clinical and molecular characteristics of this singular genetic disorder, which interestingly shares clinical features with other more common neurological disorders whose etiology remains mainly unsolved.
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Affiliation(s)
- Lorenz Peters
- Department of Neurology, University Hospital Essen, Essen, Germany
| | - Christel Depienne
- Institute of Human Genetics, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Stephan Klebe
- Department of Neurology, University Hospital Essen, Essen, Germany
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20
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Liu Y, Xu S, Huang Y, Liu S, Xu Z, Wei M, Liu J. MARCH6 promotes Papillary Thyroid Cancer development by destabilizing DHX9. Int J Biol Sci 2021; 17:3401-3412. [PMID: 34512155 PMCID: PMC8416720 DOI: 10.7150/ijbs.60628] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 07/22/2021] [Indexed: 12/23/2022] Open
Abstract
Membrane-associated ring-CH-type finger (MARCH) proteins belong to the E3 ubiquitin ligase family, which regulates protein stability by increasing ubiquitination. Recent evidence has shown that some MARCH proteins play important roles in cancer development. However, the role of MARCH6 in tumorigenesis, including thyroid tumorigenesis, remains unknown. In this study, we determined that MARCH6 was upregulated in the majority of primary papillary thyroid cancers (PTCs) at both the mRNA and protein levels. Gain-of-function and loss-of-function studies demonstrated that MARCH6 suppressed apoptosis and promoted cell cycle progression, cell proliferation, growth, migration and tumorigenesis in thyroid cancer cells. Mechanistically, MARCH6 interacted with and downregulated DHX9. Knockdown of DHX9 enhanced the proliferative and migratory abilities of thyroid cancer cells. The inhibitory effect of MARCH6 knockdown on thyroid cancer cell growth and migration was also reversed by DHX9 silencing. In addition, MARCH6 activated the AKT/mTOR signaling pathway in a manner dependent on the downregulation of DHX9. Overall, MARCH6 functions as a potential oncogene in thyroid cancer by destabilizing DHX9 and activating AKT/mTOR signaling.
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Affiliation(s)
- Yang Liu
- Department of Head and Neck Surgical Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, P. R. China
| | - Siyuan Xu
- Department of Head and Neck Surgical Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, P. R. China
| | - Ying Huang
- Department of Head and Neck Surgical Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, P. R. China
| | - Shaoyan Liu
- Department of Head and Neck Surgical Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, P. R. China
| | - Zhengang Xu
- Department of Head and Neck Surgical Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, P. R. China
| | - Minghui Wei
- Department of Head and Neck Surgical Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital & Shenzhen Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Shenzhen, P. R. China
| | - Jie Liu
- Department of Head and Neck Surgical Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, P. R. China
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21
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The Degron Architecture of Squalene Monooxygenase and How Specific Lipids Calibrate Levels of This Key Cholesterol Synthesis Enzyme. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021. [PMID: 32979157 DOI: 10.1007/5584_2020_583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register]
Abstract
Cholesterol synthesis is a fundamental process that contributes to cellular cholesterol homeostasis. Cells execute transcriptional and post-translational mechanisms to control the abundance of enzymes of the cholesterol synthesis pathway, consequently affecting cholesterol production. One such highly tuned enzyme is squalene monooxygenase (SM), which catalyzes a rate-limiting step in the pathway. A well-characterized mechanism is the cholesterol-mediated degradation of SM. Notably, lipids (cholesterol, plasmalogens, squalene, and unsaturated fatty acids) can act as cellular signals that either promote or reduce SM degradation. The N-terminal region of SM consists of the shortest known cholesterol-responsive degron, characterized by atypical membrane anchoring structures, namely a re-entrant loop and an amphipathic helix. SM also undergoes non-canonical ubiquitination on serine, a relatively uncommon attachment site for ubiquitination. The structure of the catalytic domain of SM has been solved, providing insights into the catalytic mechanisms and modes of inhibition by well-known SM inhibitors, some of which have been effective in lowering cholesterol levels in animal models. Certain human cancers have been linked to dysregulation of SM levels and activity, further emphasizing the relevance of SM in health and disease.
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22
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Kang JA, Jeon YJ. How Is the Fidelity of Proteins Ensured in Terms of Both Quality and Quantity at the Endoplasmic Reticulum? Mechanistic Insights into E3 Ubiquitin Ligases. Int J Mol Sci 2021; 22:ijms22042078. [PMID: 33669844 PMCID: PMC7923238 DOI: 10.3390/ijms22042078] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 02/16/2021] [Accepted: 02/16/2021] [Indexed: 02/06/2023] Open
Abstract
The endoplasmic reticulum (ER) is an interconnected organelle that plays fundamental roles in the biosynthesis, folding, stabilization, maturation, and trafficking of secretory and transmembrane proteins. It is the largest organelle and critically modulates nearly all aspects of life. Therefore, in the endoplasmic reticulum, an enormous investment of resources, including chaperones and protein folding facilitators, is dedicated to adequate protein maturation and delivery to final destinations. Unfortunately, the folding and assembly of proteins can be quite error-prone, which leads to the generation of misfolded proteins. Notably, protein homeostasis, referred to as proteostasis, is constantly exposed to danger by flows of misfolded proteins and subsequent protein aggregates. To maintain proteostasis, the ER triages and eliminates terminally misfolded proteins by delivering substrates to the ubiquitin–proteasome system (UPS) or to the lysosome, which is termed ER-associated degradation (ERAD) or ER-phagy, respectively. ERAD not only eliminates misfolded or unassembled proteins via protein quality control but also fine-tunes correctly folded proteins via protein quantity control. Intriguingly, the diversity and distinctive nature of E3 ubiquitin ligases determine efficiency, complexity, and specificity of ubiquitination during ERAD. ER-phagy utilizes the core autophagy machinery and eliminates ERAD-resistant misfolded proteins. Here, we conceptually outline not only ubiquitination machinery but also catalytic mechanisms of E3 ubiquitin ligases. Further, we discuss the mechanistic insights into E3 ubiquitin ligases involved in the two guardian pathways in the ER, ERAD and ER-phagy. Finally, we provide the molecular mechanisms by which ERAD and ER-phagy conduct not only protein quality control but also protein quantity control to ensure proteostasis and subsequent organismal homeostasis.
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Affiliation(s)
- Ji An Kang
- Department of Biochemistry, College of Medicine, Chungnam National University, Daejeon 35015, Korea;
- Department of Medical Science, College of Medicine, Chungnam National University, Daejeon 35015, Korea
| | - Young Joo Jeon
- Department of Biochemistry, College of Medicine, Chungnam National University, Daejeon 35015, Korea;
- Department of Medical Science, College of Medicine, Chungnam National University, Daejeon 35015, Korea
- Correspondence:
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23
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Ishihara T, Kanon H, Ban-Ishihara R, Ishihara N. Multiple assay systems to analyze the dynamics of mitochondrial nucleoids in living mammalian cells. Biochim Biophys Acta Gen Subj 2021; 1865:129874. [PMID: 33607223 DOI: 10.1016/j.bbagen.2021.129874] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2020] [Revised: 01/18/2021] [Accepted: 02/09/2021] [Indexed: 10/22/2022]
Abstract
BACKGROUND Mitochondria, which play a critical role in energy production by oxidative respiration, are highly dynamic organelles and their double membranes undergo frequent events of fusion and fission. Mitochondria are believed to be derived from the endosymbiosis of proteobacteria, and thus mitochondria still contain their own DNA, mitochondrial DNA (mtDNA). Several copies of mtDNA form mitochondrial nucleoid with DNA-binding proteins. Recently, the morphology and distribution of the mitochondrial membrane and nucleoid were reported to be cooperatively regulated during their dynamic movement. However, the molecular mechanism is unclear, because the involved molecules are poorly understood, and suitable techniques to analyze nucleoid have not been fully developed. RESULTS To solve these issues, we examined the molecular mechanism of nucleoid dynamics by two approaches. First, we constructed a new probe to perform live imaging of nucleoid dynamics using the DNA-binding domain of mitochondrial transcriptional factor A (TFAM) and the photo-convertible fluorescent protein Kikume Green-Red (KikGR). Nucleoids were visualized stably for a long period using the new probe. Second, we searched for nucleoid regulatory factors by small interfering RNA screening using HeLa cells and identified a subset of MARCH family ubiquitin ligases that affect nucleoid morphology. CONCLUSION The factors and probe, reported in this study, would be useful to reveal novel mechanisms of mitochondrial regulation. GENERAL SIGNIFICANCE The mtDNA dynamics should be concerned in the regulation of mitochondrial activity and its quality control, associated with mitochondrial membrane dynamics.
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Affiliation(s)
- Takaya Ishihara
- Department of Biological Sciences, Graduate School of Science, Osaka University, Japan; Department of Protein Biochemistry, Institute of Life Science, Kurume University, Japan.
| | - Hirotaka Kanon
- Department of Biological Sciences, Graduate School of Science, Osaka University, Japan
| | - Reiko Ban-Ishihara
- Department of Protein Biochemistry, Institute of Life Science, Kurume University, Japan
| | - Naotada Ishihara
- Department of Biological Sciences, Graduate School of Science, Osaka University, Japan; Department of Protein Biochemistry, Institute of Life Science, Kurume University, Japan.
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Scott NA, Sharpe LJ, Brown AJ. The E3 ubiquitin ligase MARCHF6 as a metabolic integrator in cholesterol synthesis and beyond. Biochim Biophys Acta Mol Cell Biol Lipids 2020; 1866:158837. [PMID: 33049405 DOI: 10.1016/j.bbalip.2020.158837] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 09/29/2020] [Accepted: 10/02/2020] [Indexed: 12/19/2022]
Abstract
MARCHF6 is a large multi-pass E3 ubiquitin ligase embedded in the membranes of the endoplasmic reticulum. It participates in endoplasmic reticulum associated degradation, including autoubiquitination, and many of its identified substrates are involved in sterol and lipid metabolism. Post-translationally, MARCHF6 expression is attuned to cholesterol status, with high cholesterol preventing its degradation and hence boosting MARCHF6 levels. By modulating MARCHF6 activity, cholesterol may regulate other aspects of cell metabolism beyond the known repertoire. Whilst we have learnt much about MARCHF6 in the past decade, there are still many more mysteries to be unravelled to fully understand its regulation, substrates, and role in human health and disease.
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Affiliation(s)
- Nicola A Scott
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Laura J Sharpe
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Andrew J Brown
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia.
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25
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The degradation-promoting roles of deubiquitinases Ubp6 and Ubp3 in cytosolic and ER protein quality control. PLoS One 2020; 15:e0232755. [PMID: 32401766 PMCID: PMC7219781 DOI: 10.1371/journal.pone.0232755] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 04/21/2020] [Indexed: 11/19/2022] Open
Abstract
The quality control of intracellular proteins is achieved by degrading misfolded proteins which cannot be refolded by molecular chaperones. In eukaryotes, such degradation is handled primarily by the ubiquitin-proteasome system. However, it remained unclear whether and how protein quality control deploys various deubiquitinases. To address this question, we screened deletions or mutation of the 20 deubiquitinase genes in Saccharomyces cerevisiae and discovered that almost half of the mutations slowed the removal of misfolded proteins whereas none of the remaining mutations accelerated this process significantly. Further characterization revealed that Ubp6 maintains the level of free ubiquitin to promote the elimination of misfolded cytosolic proteins, while Ubp3 supports the degradation of misfolded cytosolic and ER luminal proteins by different mechanisms.
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26
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Florian RT, Kraft F, Leitão E, Kaya S, Klebe S, Magnin E, van Rootselaar AF, Buratti J, Kühnel T, Schröder C, Giesselmann S, Tschernoster N, Altmueller J, Lamiral A, Keren B, Nava C, Bouteiller D, Forlani S, Jornea L, Kubica R, Ye T, Plassard D, Jost B, Meyer V, Deleuze JF, Delpu Y, Avarello MDM, Vijfhuizen LS, Rudolf G, Hirsch E, Kroes T, Reif PS, Rosenow F, Ganos C, Vidailhet M, Thivard L, Mathieu A, Bourgeron T, Kurth I, Rafehi H, Steenpass L, Horsthemke B, LeGuern E, Klein KM, Labauge P, Bennett MF, Bahlo M, Gecz J, Corbett MA, Tijssen MAJ, van den Maagdenberg AMJM, Depienne C. Unstable TTTTA/TTTCA expansions in MARCH6 are associated with Familial Adult Myoclonic Epilepsy type 3. Nat Commun 2019; 10:4919. [PMID: 31664039 PMCID: PMC6820781 DOI: 10.1038/s41467-019-12763-9] [Citation(s) in RCA: 103] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Accepted: 09/23/2019] [Indexed: 12/30/2022] Open
Abstract
Familial Adult Myoclonic Epilepsy (FAME) is a genetically heterogeneous disorder characterized by cortical tremor and seizures. Intronic TTTTA/TTTCA repeat expansions in SAMD12 (FAME1) are the main cause of FAME in Asia. Using genome sequencing and repeat-primed PCR, we identify another site of this repeat expansion, in MARCH6 (FAME3) in four European families. Analysis of single DNA molecules with nanopore sequencing and molecular combing show that expansions range from 3.3 to 14 kb on average. However, we observe considerable variability in expansion length and structure, supporting the existence of multiple expansion configurations in blood cells and fibroblasts of the same individual. Moreover, the largest expansions are associated with micro-rearrangements occurring near the expansion in 20% of cells. This study provides further evidence that FAME is caused by intronic TTTTA/TTTCA expansions in distinct genes and reveals that expansions exhibit an unexpectedly high somatic instability that can ultimately result in genomic rearrangements.
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Affiliation(s)
- Rahel T Florian
- Institute of Human Genetics, University Hospital Essen, University of Duisburg-Essen, Hufelandstraße 55, 45147, Essen, Germany
| | - Florian Kraft
- Institute of Human Genetics, Medical Faculty, RWTH Aachen University, 52062, Aachen, Germany
| | - Elsa Leitão
- Institute of Human Genetics, University Hospital Essen, University of Duisburg-Essen, Hufelandstraße 55, 45147, Essen, Germany
| | - Sabine Kaya
- Institute of Human Genetics, University Hospital Essen, University of Duisburg-Essen, Hufelandstraße 55, 45147, Essen, Germany
| | - Stephan Klebe
- Department of Neurology, Universitätsklinikum Essen, Universität Duisburg-Essen, Hufelandstraße 55, 45147, Essen, Germany
| | - Eloi Magnin
- Department of Neurology, CHU Jean Minjoz, 25000, Besançon, France
| | - Anne-Fleur van Rootselaar
- Departments of Neurology and Clinical Neurophysiology, Amsterdam UMC, University of Amsterdam, Amsterdam Neuroscience, Meibergdreef 9, 1105, AZ, Amsterdam, The Netherlands
| | - Julien Buratti
- AP-HP, Hôpital Pitié-Salpêtrière, Département de Génétique, 75013, Paris, France
| | - Theresa Kühnel
- Institute of Human Genetics, University Hospital Essen, University of Duisburg-Essen, Hufelandstraße 55, 45147, Essen, Germany
| | - Christopher Schröder
- Institute of Human Genetics, University Hospital Essen, University of Duisburg-Essen, Hufelandstraße 55, 45147, Essen, Germany
| | - Sebastian Giesselmann
- Institute of Human Genetics, Medical Faculty, RWTH Aachen University, 52062, Aachen, Germany
| | - Nikolai Tschernoster
- Cologne Center for Genomics, Center for Molecular Medicine Cologne (CMMC), University of Cologne, Weyertal 115b, 50931, Cologne, Germany
| | - Janine Altmueller
- Cologne Center for Genomics, Center for Molecular Medicine Cologne (CMMC), University of Cologne, Weyertal 115b, 50931, Cologne, Germany
| | - Anaide Lamiral
- Department of Neurology, CHU Jean Minjoz, 25000, Besançon, France
| | - Boris Keren
- AP-HP, Hôpital Pitié-Salpêtrière, Département de Génétique, 75013, Paris, France
| | - Caroline Nava
- AP-HP, Hôpital Pitié-Salpêtrière, Département de Génétique, 75013, Paris, France
- Institut du Cerveau et de la Moelle épinière (ICM), Sorbonne Université, UMR S 1127, Inserm U1127, CNRS UMR 7225, F-75013, Paris, France
| | - Delphine Bouteiller
- Institut du Cerveau et de la Moelle épinière (ICM), Sorbonne Université, UMR S 1127, Inserm U1127, CNRS UMR 7225, F-75013, Paris, France
| | - Sylvie Forlani
- Institut du Cerveau et de la Moelle épinière (ICM), Sorbonne Université, UMR S 1127, Inserm U1127, CNRS UMR 7225, F-75013, Paris, France
| | - Ludmila Jornea
- Institut du Cerveau et de la Moelle épinière (ICM), Sorbonne Université, UMR S 1127, Inserm U1127, CNRS UMR 7225, F-75013, Paris, France
| | - Regina Kubica
- Institute of Human Genetics, University Hospital Essen, University of Duisburg-Essen, Hufelandstraße 55, 45147, Essen, Germany
| | - Tao Ye
- IGBMC, CNRS UMR 7104/INSERM U1258/Université de Strasbourg, 1 Rue Laurent Fries, 67400, Illkirch-Graffenstaden, France
| | - Damien Plassard
- IGBMC, CNRS UMR 7104/INSERM U1258/Université de Strasbourg, 1 Rue Laurent Fries, 67400, Illkirch-Graffenstaden, France
| | - Bernard Jost
- IGBMC, CNRS UMR 7104/INSERM U1258/Université de Strasbourg, 1 Rue Laurent Fries, 67400, Illkirch-Graffenstaden, France
| | - Vincent Meyer
- Centre National de Recherche en Génomique Humaine (CNRGH), Institut de Biologie François Jacob, CEA, Université Paris-Saclay, F-91057, Evry, France
| | - Jean-François Deleuze
- Centre National de Recherche en Génomique Humaine (CNRGH), Institut de Biologie François Jacob, CEA, Université Paris-Saclay, F-91057, Evry, France
| | - Yannick Delpu
- Genomic Vision, 80 Rue des Meuniers, 92220, Bagneux, France
| | | | - Lisanne S Vijfhuizen
- Department of Human Genetics, Leiden University Medical Center, Albinusdreef 2, 2333, ZA, Leiden, The Netherlands
| | - Gabrielle Rudolf
- IGBMC, CNRS UMR 7104/INSERM U1258/Université de Strasbourg, 1 Rue Laurent Fries, 67400, Illkirch-Graffenstaden, France
- Department of Neurology-centre de référence des epilepsies rares, University Hospital of Strasbourg, 1 Avenue Molière, 67200, Strasbourg, France
| | - Edouard Hirsch
- Department of Neurology-centre de référence des epilepsies rares, University Hospital of Strasbourg, 1 Avenue Molière, 67200, Strasbourg, France
| | - Thessa Kroes
- School of Biological Sciences, School of Medicine and Robinson Research Institute, The University of Adelaide, Adelaide, 5005, SA, Australia
| | - Philipp S Reif
- Epilepsy Center Frankfurt Rhine-Main, Department of Neurology, Goethe University and LOEWE Center for Personalized Translational Epilepsy Research (CePTER), 60323, Frankfurt am Main, Germany
- Department of Neurology, Epilepsy Center Hessen, Philipps University, 35037, Marburg, Germany
| | - Felix Rosenow
- Epilepsy Center Frankfurt Rhine-Main, Department of Neurology, Goethe University and LOEWE Center for Personalized Translational Epilepsy Research (CePTER), 60323, Frankfurt am Main, Germany
- Department of Neurology, Epilepsy Center Hessen, Philipps University, 35037, Marburg, Germany
| | - Christos Ganos
- Department of Neurology, Charité University Medicine Berlin, 10117, Berlin, Germany
| | - Marie Vidailhet
- Institut du Cerveau et de la Moelle épinière (ICM), Sorbonne Université, UMR S 1127, Inserm U1127, CNRS UMR 7225, F-75013, Paris, France
- APHP, Hôpital Pitié-Salpêtrière, Département de Neurologie, 75013, Paris, France
| | - Lionel Thivard
- APHP, Hôpital Pitié-Salpêtrière, Département de Neurologie, 75013, Paris, France
| | - Alexandre Mathieu
- Human Genetics and Cognitive Functions, Pasteur Institute, UMR3571 CNRS, Université de Paris, 75015, Paris, France
| | - Thomas Bourgeron
- Human Genetics and Cognitive Functions, Pasteur Institute, UMR3571 CNRS, Université de Paris, 75015, Paris, France
| | - Ingo Kurth
- Institute of Human Genetics, Medical Faculty, RWTH Aachen University, 52062, Aachen, Germany
| | - Haloom Rafehi
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, 3052, VIC, Australia
- Department of Medical Biology, University of Melbourne, Melbourne, 3010, VIC, Australia
- Epilepsy Research Centre, Department of Medicine, University of Melbourne, Austin Health, Heidelberg, 3084, VIC, Australia
| | - Laura Steenpass
- Institute of Human Genetics, University Hospital Essen, University of Duisburg-Essen, Hufelandstraße 55, 45147, Essen, Germany
| | - Bernhard Horsthemke
- Institute of Human Genetics, University Hospital Essen, University of Duisburg-Essen, Hufelandstraße 55, 45147, Essen, Germany
| | - Eric LeGuern
- AP-HP, Hôpital Pitié-Salpêtrière, Département de Génétique, 75013, Paris, France
- Institut du Cerveau et de la Moelle épinière (ICM), Sorbonne Université, UMR S 1127, Inserm U1127, CNRS UMR 7225, F-75013, Paris, France
| | - Karl Martin Klein
- Epilepsy Center Frankfurt Rhine-Main, Department of Neurology, Goethe University and LOEWE Center for Personalized Translational Epilepsy Research (CePTER), 60323, Frankfurt am Main, Germany
- Department of Neurology, Epilepsy Center Hessen, Philipps University, 35037, Marburg, Germany
- Departments of Clinical Neurosciences, Medical Genetics and Community Health Sciences, Hotchkiss Brain Institute & Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, 2500 University Dr NW, Calgary, AB, T2N 1N4, Canada
| | - Pierre Labauge
- Department of Neurology, Gui de Chauliac University Hospital, 34295, Montpellier, France
| | - Mark F Bennett
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, 3052, VIC, Australia
- Department of Medical Biology, University of Melbourne, Melbourne, 3010, VIC, Australia
- Epilepsy Research Centre, Department of Medicine, University of Melbourne, Austin Health, Heidelberg, 3084, VIC, Australia
| | - Melanie Bahlo
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, 3052, VIC, Australia
- Department of Medical Biology, University of Melbourne, Melbourne, 3010, VIC, Australia
| | - Jozef Gecz
- School of Biological Sciences, School of Medicine and Robinson Research Institute, The University of Adelaide, Adelaide, 5005, SA, Australia
- South Australian Health and Medical Research Institute, The University of Adelaide, Adelaide, 5005, SA, Australia
| | - Mark A Corbett
- School of Biological Sciences, School of Medicine and Robinson Research Institute, The University of Adelaide, Adelaide, 5005, SA, Australia
| | - Marina A J Tijssen
- Department of Neurology, University Medical Center Groningen, University of Groningen, 9700, AB, Groningen, the Netherlands
| | - Arn M J M van den Maagdenberg
- Department of Human Genetics, Leiden University Medical Center, Albinusdreef 2, 2333, ZA, Leiden, The Netherlands
- Department of Neurology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, Leiden, The Netherlands
| | - Christel Depienne
- Institute of Human Genetics, University Hospital Essen, University of Duisburg-Essen, Hufelandstraße 55, 45147, Essen, Germany.
- Institut du Cerveau et de la Moelle épinière (ICM), Sorbonne Université, UMR S 1127, Inserm U1127, CNRS UMR 7225, F-75013, Paris, France.
- IGBMC, CNRS UMR 7104/INSERM U1258/Université de Strasbourg, 1 Rue Laurent Fries, 67400, Illkirch-Graffenstaden, France.
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27
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Buchwalter A, Schulte R, Tsai H, Capitanio J, Hetzer M. Selective clearance of the inner nuclear membrane protein emerin by vesicular transport during ER stress. eLife 2019; 8:e49796. [PMID: 31599721 PMCID: PMC6802967 DOI: 10.7554/elife.49796] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Accepted: 10/09/2019] [Indexed: 12/17/2022] Open
Abstract
The inner nuclear membrane (INM) is a subdomain of the endoplasmic reticulum (ER) that is gated by the nuclear pore complex. It is unknown whether proteins of the INM and ER are degraded through shared or distinct pathways in mammalian cells. We applied dynamic proteomics to profile protein half-lives and report that INM and ER residents turn over at similar rates, indicating that the INM's unique topology is not a barrier to turnover. Using a microscopy approach, we observed that the proteasome can degrade INM proteins in situ. However, we also uncovered evidence for selective, vesicular transport-mediated turnover of a single INM protein, emerin, that is potentiated by ER stress. Emerin is rapidly cleared from the INM by a mechanism that requires emerin's LEM domain to mediate vesicular trafficking to lysosomes. This work demonstrates that the INM can be dynamically remodeled in response to environmental inputs.
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Affiliation(s)
- Abigail Buchwalter
- Cardiovascular Research InstituteUniversity of California, San FranciscoSan FranciscoUnited States
- Department of PhysiologyUniversity of California, San FranciscoSan FranciscoUnited States
- Chan Zuckerberg BiohubSan FranciscoUnited States
| | - Roberta Schulte
- The Salk Institute for Biological StudiesLa JollaUnited States
| | - Hsiao Tsai
- The Salk Institute for Biological StudiesLa JollaUnited States
| | | | - Martin Hetzer
- The Salk Institute for Biological StudiesLa JollaUnited States
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28
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Tax G, Lia A, Santino A, Roversi P. Modulation of ERQC and ERAD: A Broad-Spectrum Spanner in the Works of Cancer Cells? JOURNAL OF ONCOLOGY 2019; 2019:8384913. [PMID: 31662755 PMCID: PMC6791201 DOI: 10.1155/2019/8384913] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Accepted: 08/27/2019] [Indexed: 12/21/2022]
Abstract
Endoplasmic reticulum glycoprotein folding quality control (ERQC) and ER-associated degradation (ERAD) preside over cellular glycoprotein secretion and maintain steady glycoproteostasis. When cells turn malignant, cancer cell plasticity is affected and supported either by point mutations, preferential isoform selection, altered expression levels, or shifts to conformational equilibria of a secreted glycoprotein. Such changes are crucial in mediating altered extracellular signalling, metabolic behavior, and adhesion properties of cancer cells. It is therefore conceivable that interference with ERQC and/or ERAD can be used to selectively damage cancers. Indeed, inhibitors of the late stages of ERAD are already in the clinic against cancers such as multiple myeloma. Here, we review recent advances in our understanding of the complex relationship between glycoproteostasis and cancer biology and discuss the potential of ERQC and ERAD modulators for the selective targeting of cancer cell plasticity.
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Affiliation(s)
- Gábor Tax
- Leicester Institute of Structural and Chemical Biology, Department of Molecular and Cell Biology, University of Leicester, Henry Wellcome Building, Lancaster Road, Leicester LE1 7RH, UK
| | - Andrea Lia
- Leicester Institute of Structural and Chemical Biology, Department of Molecular and Cell Biology, University of Leicester, Henry Wellcome Building, Lancaster Road, Leicester LE1 7RH, UK
- Institute of Sciences of Food Production, C.N.R. Unit of Lecce, via Monteroni, I-73100 Lecce, Italy
| | - Angelo Santino
- Institute of Sciences of Food Production, C.N.R. Unit of Lecce, via Monteroni, I-73100 Lecce, Italy
| | - Pietro Roversi
- Leicester Institute of Structural and Chemical Biology, Department of Molecular and Cell Biology, University of Leicester, Henry Wellcome Building, Lancaster Road, Leicester LE1 7RH, UK
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29
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Scheffer J, Hasenjäger S, Taxis C. Degradation of integral membrane proteins modified with the photosensitive degron module requires the cytosolic endoplasmic reticulum-associated degradation pathway. Mol Biol Cell 2019; 30:2558-2570. [PMID: 31411939 PMCID: PMC6740197 DOI: 10.1091/mbc.e18-12-0754] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Protein quality mechanisms are fundamental for proteostasis of eukaryotic cells. Endoplasmic reticulum–associated degradation (ERAD) is a well-studied pathway that ensures quality control of secretory and endoplasmic reticulum (ER)–resident proteins. Different branches of ERAD are involved in degradation of malfolded secretory proteins, depending on the localization of the misfolded part, the ER lumen (ERAD-L), the ER membrane (ERAD-M), and the cytosol (ERAD-C). Here we report that modification of several ER transmembrane proteins with the photosensitive degron (psd) module resulted in light-dependent degradation of the membrane proteins via the ERAD-C pathway. We found dependency on the ubiquitylation machinery including the ubiquitin-activating enzyme Uba1, the ubiquitin-conjugating enzymes Ubc6 and Ubc7, and the ubiquitin–protein ligase Doa10. Moreover, we found involvement of the Cdc48 AAA-ATPase complex members Ufd1 and Npl4, as well as the proteasome, in degradation of Sec62-myc-psd. Thus, our work shows that ERAD-C substrates can be systematically generated via synthetic degron constructs, which facilitates future investigations of the ERAD-C pathway.
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Affiliation(s)
- Johannes Scheffer
- Department of Chemistry/Biochemistry, Philipps-University Marburg, 35043 Marburg, Germany
| | - Sophia Hasenjäger
- Department of Biology/Genetics, Philipps-University Marburg, 35043 Marburg, Germany
| | - Christof Taxis
- Department of Biology/Genetics, Philipps-University Marburg, 35043 Marburg, Germany
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30
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Sharpe LJ, Howe V, Scott NA, Luu W, Phan L, Berk JM, Hochstrasser M, Brown AJ. Cholesterol increases protein levels of the E3 ligase MARCH6 and thereby stimulates protein degradation. J Biol Chem 2018; 294:2436-2448. [PMID: 30545937 DOI: 10.1074/jbc.ra118.005069] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Revised: 12/06/2018] [Indexed: 12/12/2022] Open
Abstract
The E3 ligase membrane-associated ring-CH-type finger 6 (MARCH6) is a polytopic enzyme bound to the membranes of the endoplasmic reticulum. It controls levels of several known protein substrates, including a key enzyme in cholesterol synthesis, squalene monooxygenase. However, beyond its own autodegradation, little is known about how MARCH6 itself is regulated. Using CRISPR/Cas9 gene-editing, MARCH6 overexpression, and immunoblotting, we found here that cholesterol stabilizes MARCH6 protein endogenously and in HEK293 cells that stably express MARCH6. Conversely, MARCH6-deficient HEK293 and HeLa cells lost their ability to degrade squalene monooxygenase in a cholesterol-dependent manner. The ability of cholesterol to boost MARCH6 did not seem to involve a putative sterol-sensing domain in this E3 ligase, but was abolished when either membrane extraction by valosin-containing protein (VCP/p97) or proteasomal degradation was inhibited. Furthermore, cholesterol-mediated stabilization was absent in two MARCH6 mutants that are unable to degrade themselves, indicating that cholesterol stabilizes MARCH6 protein by preventing its autodegradation. Experiments with chemical chaperones suggested that this likely occurs through a conformational change in MARCH6 upon cholesterol addition. Moreover, cholesterol reduced the levels of at least three known MARCH6 substrates, indicating that cholesterol-mediated MARCH6 stabilization increases its activity. Our findings highlight an important new role for cholesterol in controlling levels of proteins, extending the known repertoire of cholesterol homeostasis players.
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Affiliation(s)
- Laura J Sharpe
- From the School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales 2052, Australia and
| | - Vicky Howe
- From the School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales 2052, Australia and
| | - Nicola A Scott
- From the School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales 2052, Australia and
| | - Winnie Luu
- From the School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales 2052, Australia and
| | - Lisa Phan
- From the School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales 2052, Australia and
| | - Jason M Berk
- the Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520
| | - Mark Hochstrasser
- the Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520
| | - Andrew J Brown
- From the School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales 2052, Australia and
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31
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Mehrtash AB, Hochstrasser M. Ubiquitin-dependent protein degradation at the endoplasmic reticulum and nuclear envelope. Semin Cell Dev Biol 2018; 93:111-124. [PMID: 30278225 DOI: 10.1016/j.semcdb.2018.09.013] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 09/26/2018] [Accepted: 09/27/2018] [Indexed: 01/01/2023]
Abstract
Numerous nascent proteins undergo folding and maturation within the luminal and membrane compartments of the endoplasmic reticulum (ER). Despite the presence of various factors in the ER that promote protein folding, many proteins fail to properly fold and assemble and are subsequently degraded. Regulatory proteins in the ER also undergo degradation in a way that is responsive to stimuli or the changing needs of the cell. As in most cellular compartments, the ubiquitin-proteasome system (UPS) is responsible for the majority of the degradation at the ER-in a process termed ER-associated degradation (ERAD). Autophagic processes utilizing ubiquitin-like protein-conjugating systems also play roles in protein degradation at the ER. The ER is continuous with the nuclear envelope (NE), which consists of the outer nuclear membrane (ONM) and inner nuclear membrane (INM). While ERAD is known also to occur at the NE, only some of the ERAD ubiquitin-ligation pathways function at the INM. Protein degradation machineries in the ER/NE target a wide variety of substrates in multiple cellular compartments, including the cytoplasm, nucleoplasm, ER lumen, ER membrane, and the NE. Here, we review the protein degradation machineries of the ER and NE and the underlying mechanisms dictating recognition and processing of substrates by these machineries.
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Affiliation(s)
- Adrian B Mehrtash
- Department of Molecular, Cellular, & Developmental Biology, Yale University, New Haven, 06520, CT, USA.
| | - Mark Hochstrasser
- Department of Molecular Biophysics & Biochemistry, Yale University, New Haven, CT, 06520, USA; Department of Molecular, Cellular, & Developmental Biology, Yale University, New Haven, 06520, CT, USA.
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32
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Coordinate regulation of mutant NPC1 degradation by selective ER autophagy and MARCH6-dependent ERAD. Nat Commun 2018; 9:3671. [PMID: 30202070 PMCID: PMC6131187 DOI: 10.1038/s41467-018-06115-2] [Citation(s) in RCA: 85] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 07/26/2018] [Indexed: 12/30/2022] Open
Abstract
Niemann–Pick type C disease is a fatal, progressive neurodegenerative disorder caused by loss-of-function mutations in NPC1, a multipass transmembrane glycoprotein essential for intracellular lipid trafficking. We sought to define the cellular machinery controlling degradation of the most common disease-causing mutant, I1061T NPC1. We show that this mutant is degraded, in part, by the proteasome following MARCH6-dependent ERAD. Unexpectedly, we demonstrate that I1061T NPC1 is also degraded by a recently described autophagic pathway called selective ER autophagy (ER-phagy). We establish the importance of ER-phagy both in vitro and in vivo, and identify I1061T as a misfolded endogenous substrate for this FAM134B-dependent process. Subcellular fractionation of I1061T Npc1 mouse tissues and analysis of human samples show alterations of key components of ER-phagy, including FAM134B. Our data establish that I1061T NPC1 is recognized in the ER and degraded by two different pathways that function in a complementary fashion to regulate protein turnover. Niemann-Pick type C1 disease is most commonly caused by the allele NPC1 I1061T, which is misfolded in the ER and rapidly degraded by the ubiquitin proteasome system. Here the authors show that the I1061T mutant is also degraded by ER-phagy.
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33
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Berner N, Reutter KR, Wolf DH. Protein Quality Control of the Endoplasmic Reticulum and Ubiquitin-Proteasome-Triggered Degradation of Aberrant Proteins: Yeast Pioneers the Path. Annu Rev Biochem 2018; 87:751-782. [PMID: 29394096 DOI: 10.1146/annurev-biochem-062917-012749] [Citation(s) in RCA: 97] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Cells must constantly monitor the integrity of their macromolecular constituents. Proteins are the most versatile class of macromolecules but are sensitive to structural alterations. Misfolded or otherwise aberrant protein structures lead to dysfunction and finally aggregation. Their presence is linked to aging and a plethora of severe human diseases. Thus, misfolded proteins have to be rapidly eliminated. Secretory proteins constitute more than one-third of the eukaryotic proteome. They are imported into the endoplasmic reticulum (ER), where they are folded and modified. A highly elaborated machinery controls their folding, recognizes aberrant folding states, and retrotranslocates permanently misfolded proteins from the ER back to the cytosol. In the cytosol, they are degraded by the highly selective ubiquitin-proteasome system. This process of protein quality control followed by proteasomal elimination of the misfolded protein is termed ER-associated degradation (ERAD), and it depends on an intricate interplay between the ER and the cytosol.
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Affiliation(s)
- Nicole Berner
- Institute of Biochemistry and Technical Biochemistry, University of Stuttgart, 70569 Stuttgart, Germany; , ,
| | - Karl-Richard Reutter
- Institute of Biochemistry and Technical Biochemistry, University of Stuttgart, 70569 Stuttgart, Germany; , ,
| | - Dieter H Wolf
- Institute of Biochemistry and Technical Biochemistry, University of Stuttgart, 70569 Stuttgart, Germany; , ,
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Abstract
As a compartment border, the nuclear envelope (NE) needs to serve as both a protective membrane shell for the genome and a versatile communication interface between the nucleus and the cytoplasm. Despite its important structural role in sheltering the genome, the NE is a dynamic and highly adaptable boundary that changes composition during differentiation, deforms in response to mechanical challenges, can be repaired upon rupture and even rapidly disassembles and reforms during open mitosis. NE remodelling is fundamentally involved in cell growth, division and differentiation, and if perturbed can lead to devastating diseases such as muscular dystrophies or premature ageing.
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James AW, Gowsalya R, Nachiappan V. Dolichyl pyrophosphate phosphatase-mediated N -glycosylation defect dysregulates lipid homeostasis in Saccharomyces cerevisiae. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:1705-1718. [DOI: 10.1016/j.bbalip.2016.08.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 08/05/2016] [Accepted: 08/09/2016] [Indexed: 12/28/2022]
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