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Li H, Sun S. Protein Aggregation in the ER: Calm behind the Storm. Cells 2021; 10:cells10123337. [PMID: 34943844 PMCID: PMC8699410 DOI: 10.3390/cells10123337] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Revised: 11/19/2021] [Accepted: 11/22/2021] [Indexed: 02/06/2023] Open
Abstract
As one of the largest organelles in eukaryotic cells, the endoplasmic reticulum (ER) plays a vital role in the synthesis, folding, and assembly of secretory and membrane proteins. To maintain its homeostasis, the ER is equipped with an elaborate network of protein folding chaperones and multiple quality control pathways whose cooperative actions safeguard the fidelity of protein biogenesis. However, due to genetic abnormalities, the error-prone nature of protein folding and assembly, and/or defects or limited capacities of the protein quality control systems, nascent proteins may become misfolded and fail to exit the ER. If not cleared efficiently, the progressive accumulation of misfolded proteins within the ER may result in the formation of toxic protein aggregates, leading to the so-called “ER storage diseases”. In this review, we first summarize our current understanding of the protein folding and quality control networks in the ER, including chaperones, unfolded protein response (UPR), ER-associated protein degradation (ERAD), and ER-selective autophagy (ER-phagy). We then survey recent research progress on a few ER storage diseases, with a focus on the role of ER quality control in the disease etiology, followed by a discussion on outstanding questions and emerging concepts in the field.
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Affiliation(s)
- Haisen Li
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI 48201, USA;
| | - Shengyi Sun
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI 48201, USA;
- Department of Biochemistry, Microbiology and Immunology, Wayne State University School of Medicine, Detroit, MI 48201, USA
- Correspondence:
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2
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Padilla-Godínez FJ, Ramos-Acevedo R, Martínez-Becerril HA, Bernal-Conde LD, Garrido-Figueroa JF, Hiriart M, Hernández-López A, Argüero-Sánchez R, Callea F, Guerra-Crespo M. Protein Misfolding and Aggregation: The Relatedness between Parkinson's Disease and Hepatic Endoplasmic Reticulum Storage Disorders. Int J Mol Sci 2021; 22:ijms222212467. [PMID: 34830348 PMCID: PMC8619695 DOI: 10.3390/ijms222212467] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 10/18/2021] [Accepted: 10/19/2021] [Indexed: 12/21/2022] Open
Abstract
Dysfunction of cellular homeostasis can lead to misfolding of proteins thus acquiring conformations prone to polymerization into pathological aggregates. This process is associated with several disorders, including neurodegenerative diseases, such as Parkinson’s disease (PD), and endoplasmic reticulum storage disorders (ERSDs), like alpha-1-antitrypsin deficiency (AATD) and hereditary hypofibrinogenemia with hepatic storage (HHHS). Given the shared pathophysiological mechanisms involved in such conditions, it is necessary to deepen our understanding of the basic principles of misfolding and aggregation akin to these diseases which, although heterogeneous in symptomatology, present similarities that could lead to potential mutual treatments. Here, we review: (i) the pathological bases leading to misfolding and aggregation of proteins involved in PD, AATD, and HHHS: alpha-synuclein, alpha-1-antitrypsin, and fibrinogen, respectively, (ii) the evidence linking each protein aggregation to the stress mechanisms occurring in the endoplasmic reticulum (ER) of each pathology, (iii) a comparison of the mechanisms related to dysfunction of proteostasis and regulation of homeostasis between the diseases (such as the unfolded protein response and/or autophagy), (iv) and clinical perspectives regarding possible common treatments focused on improving the defensive responses to protein aggregation for diseases as different as PD, and ERSDs.
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Affiliation(s)
- Francisco J. Padilla-Godínez
- Neurosciences Division, Cell Physiology Institute, National Autonomous University of Mexico, Mexico City 04510, Mexico; (F.J.P.-G.); (R.R.-A.); (H.A.M.-B.); (L.D.B.-C.); (J.F.G.-F.); (M.H.)
- Regenerative Medicine Laboratory, Department of Surgery, Faculty of Medicine, National Autonomous University of Mexico, Mexico City 04510, Mexico; (A.H.-L.); (R.A.-S.)
| | - Rodrigo Ramos-Acevedo
- Neurosciences Division, Cell Physiology Institute, National Autonomous University of Mexico, Mexico City 04510, Mexico; (F.J.P.-G.); (R.R.-A.); (H.A.M.-B.); (L.D.B.-C.); (J.F.G.-F.); (M.H.)
- Regenerative Medicine Laboratory, Department of Surgery, Faculty of Medicine, National Autonomous University of Mexico, Mexico City 04510, Mexico; (A.H.-L.); (R.A.-S.)
| | - Hilda Angélica Martínez-Becerril
- Neurosciences Division, Cell Physiology Institute, National Autonomous University of Mexico, Mexico City 04510, Mexico; (F.J.P.-G.); (R.R.-A.); (H.A.M.-B.); (L.D.B.-C.); (J.F.G.-F.); (M.H.)
- Regenerative Medicine Laboratory, Department of Surgery, Faculty of Medicine, National Autonomous University of Mexico, Mexico City 04510, Mexico; (A.H.-L.); (R.A.-S.)
| | - Luis D. Bernal-Conde
- Neurosciences Division, Cell Physiology Institute, National Autonomous University of Mexico, Mexico City 04510, Mexico; (F.J.P.-G.); (R.R.-A.); (H.A.M.-B.); (L.D.B.-C.); (J.F.G.-F.); (M.H.)
- Regenerative Medicine Laboratory, Department of Surgery, Faculty of Medicine, National Autonomous University of Mexico, Mexico City 04510, Mexico; (A.H.-L.); (R.A.-S.)
| | - Jerónimo F. Garrido-Figueroa
- Neurosciences Division, Cell Physiology Institute, National Autonomous University of Mexico, Mexico City 04510, Mexico; (F.J.P.-G.); (R.R.-A.); (H.A.M.-B.); (L.D.B.-C.); (J.F.G.-F.); (M.H.)
- Regenerative Medicine Laboratory, Department of Surgery, Faculty of Medicine, National Autonomous University of Mexico, Mexico City 04510, Mexico; (A.H.-L.); (R.A.-S.)
| | - Marcia Hiriart
- Neurosciences Division, Cell Physiology Institute, National Autonomous University of Mexico, Mexico City 04510, Mexico; (F.J.P.-G.); (R.R.-A.); (H.A.M.-B.); (L.D.B.-C.); (J.F.G.-F.); (M.H.)
| | - Adriana Hernández-López
- Regenerative Medicine Laboratory, Department of Surgery, Faculty of Medicine, National Autonomous University of Mexico, Mexico City 04510, Mexico; (A.H.-L.); (R.A.-S.)
| | - Rubén Argüero-Sánchez
- Regenerative Medicine Laboratory, Department of Surgery, Faculty of Medicine, National Autonomous University of Mexico, Mexico City 04510, Mexico; (A.H.-L.); (R.A.-S.)
| | - Francesco Callea
- Department of Histopathology, Bugando Medical Centre, Catholic University of Healthy and Allied Sciences, Mwanza 1464, Tanzania;
| | - Magdalena Guerra-Crespo
- Neurosciences Division, Cell Physiology Institute, National Autonomous University of Mexico, Mexico City 04510, Mexico; (F.J.P.-G.); (R.R.-A.); (H.A.M.-B.); (L.D.B.-C.); (J.F.G.-F.); (M.H.)
- Regenerative Medicine Laboratory, Department of Surgery, Faculty of Medicine, National Autonomous University of Mexico, Mexico City 04510, Mexico; (A.H.-L.); (R.A.-S.)
- Correspondence:
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3
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Vilar R, Lukowski SW, Garieri M, Di Sanza C, Neerman-Arbez M, Fish RJ. Chemical Modulators of Fibrinogen Production and Their Impact on Venous Thrombosis. Thromb Haemost 2020; 121:433-448. [PMID: 33302304 DOI: 10.1055/s-0040-1718414] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Thrombosis is a leading cause of morbidity and mortality. Fibrinogen, the soluble substrate for fibrin-based clotting, has a central role in haemostasis and thrombosis and its plasma concentration correlates with cardiovascular disease event risk and a prothrombotic state in experimental models. We aimed to identify chemical entities capable of changing fibrinogen production and test their impact on experimental thrombosis. A total of 1,280 bioactive compounds were screened for their ability to alter fibrinogen production by hepatocyte-derived cancer cells and a selected panel was tested in zebrafish larvae. Anthralin and all-trans retinoic acid (RA) were identified as fibrinogen-lowering and fibrinogen-increasing moieties, respectively. In zebrafish larvae, anthralin prolonged laser-induced venous- occlusion times and reduced thrombocyte accumulation at injury sites. RA had opposite effects. Treatment with RA, a nuclear receptor ligand, increased fibrinogen mRNA levels. Using an antisense morpholino oligonucleotide to deplete zebrafish fibrinogen, we correlated a shortening of laser-induced venous thrombosis times with RA treatment and fibrinogen protein levels. Anthralin had little effect on fibrinogen mRNA in zebrafish larvae, despite leading to lower detectable fibrinogen. Therefore, we made a proteomic scan of anthralin-treated cells and larvae. A reduced representation of proteins linked to the canonical secretory pathway was detected, suggesting that anthralin affects protein secretion. In summary, we found that chemical modulation of fibrinogen levels correlates with measured effects on experimental venous thrombosis and could be investigated as a therapeutic avenue for thrombosis prevention.
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Affiliation(s)
- Rui Vilar
- Department of Genetic Medicine and Development, University of Geneva Faculty of Medicine, Geneva, Switzerland
| | - Samuel W Lukowski
- Department of Genetic Medicine and Development, University of Geneva Faculty of Medicine, Geneva, Switzerland.,Institute for Molecular Bioscience, The University of Queensland, Saint Lucia, Queensland, Australia
| | - Marco Garieri
- Department of Genetic Medicine and Development, University of Geneva Faculty of Medicine, Geneva, Switzerland
| | - Corinne Di Sanza
- Department of Genetic Medicine and Development, University of Geneva Faculty of Medicine, Geneva, Switzerland
| | - Marguerite Neerman-Arbez
- Department of Genetic Medicine and Development, University of Geneva Faculty of Medicine, Geneva, Switzerland.,iGE3, Institute of Genetics and Genomics in Geneva, Geneva, Switzerland
| | - Richard J Fish
- Department of Genetic Medicine and Development, University of Geneva Faculty of Medicine, Geneva, Switzerland
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Asselta R, Paraboschi EM, Duga S. Hereditary Hypofibrinogenemia with Hepatic Storage. Int J Mol Sci 2020; 21:ijms21217830. [PMID: 33105716 PMCID: PMC7659954 DOI: 10.3390/ijms21217830] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 10/21/2020] [Accepted: 10/21/2020] [Indexed: 12/14/2022] Open
Abstract
Fibrinogen is a 340-kDa plasma glycoprotein constituted by two sets of symmetrical trimers, each formed by the Aα, Bβ, and γ chains (respectively coded by the FGA, FGB, and FGG genes). Quantitative fibrinogen deficiencies (hypofibrinogenemia, afibrinogenemia) are rare congenital disorders characterized by low or unmeasurable plasma fibrinogen antigen levels. Their genetic basis is represented by mutations within the fibrinogen genes. To date, only eight mutations, all affecting a small region of the fibrinogen γ chain, have been reported to cause hereditary hypofibrinogenemia with hepatic storage (HHHS), a disorder characterized by protein aggregation in the endoplasmic reticulum, hypofibrinogenemia, and liver disease of variable severity. Here, we will briefly review the clinic characteristics of HHHS patients and the histological feature of their hepatic inclusions, and we will focus on the molecular genetic basis of this peculiar type of coagulopathy.
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Affiliation(s)
- Rosanna Asselta
- Department of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, Pieve Emanuele, 20090 Milan, Italy; (E.M.P.); (S.D.)
- Humanitas Clinical and Research Center, IRCCS, Via Manzoni 56, Rozzano, 20089 Milan, Italy
- Correspondence: ; Tel.: +39-02-8224-5215
| | - Elvezia Maria Paraboschi
- Department of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, Pieve Emanuele, 20090 Milan, Italy; (E.M.P.); (S.D.)
- Humanitas Clinical and Research Center, IRCCS, Via Manzoni 56, Rozzano, 20089 Milan, Italy
| | - Stefano Duga
- Department of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, Pieve Emanuele, 20090 Milan, Italy; (E.M.P.); (S.D.)
- Humanitas Clinical and Research Center, IRCCS, Via Manzoni 56, Rozzano, 20089 Milan, Italy
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5
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In focus in HCB. Histochem Cell Biol 2020; 153:71-75. [PMID: 31993752 DOI: 10.1007/s00418-020-01843-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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6
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Chiritoiu M, Chiritoiu GN, Munteanu CVA, Pastrama F, Ivessa NE, Petrescu SM. EDEM1 Drives Misfolded Protein Degradation via ERAD and Exploits ER-Phagy as Back-Up Mechanism When ERAD Is Impaired. Int J Mol Sci 2020; 21:ijms21103468. [PMID: 32423001 PMCID: PMC7279049 DOI: 10.3390/ijms21103468] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 04/30/2020] [Accepted: 05/07/2020] [Indexed: 01/20/2023] Open
Abstract
Endoplasmic reticulum (ER)-associated degradation (ERAD) is the main mechanism of targeting ER proteins for degradation to maintain homeostasis, and perturbations of ERAD lead to pathological conditions. ER-degradation enhancing α-mannosidase-like (EDEM1) was proposed to extract terminally misfolded proteins from the calnexin folding cycle and target them for degradation by ERAD. Here, using mass-spectrometry and biochemical methods, we show that EDEM1 is found in auto-regulatory complexes with ERAD components. Moreover, the N-terminal disordered region of EDEM1 mediates protein–protein interaction with misfolded proteins, whilst the absence of this domain significantly impairs their degradation. We also determined that overexpression of EDEM1 can induce degradation, even when proteasomal activity is severely impaired, by promoting the formation of aggregates, which can be further degraded by autophagy. Therefore, we propose that EDEM1 maintains ER homeostasis and mediates ERAD client degradation via autophagy when either dislocation or proteasomal degradation are impaired.
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Affiliation(s)
- Marioara Chiritoiu
- Department of Molecular Cell Biology, Institute of Biochemistry, Splaiul Independentei 296, 060031 Bucharest 17, Romania; (M.C.); (G.N.C.)
| | - Gabriela N. Chiritoiu
- Department of Molecular Cell Biology, Institute of Biochemistry, Splaiul Independentei 296, 060031 Bucharest 17, Romania; (M.C.); (G.N.C.)
| | - Cristian V. A. Munteanu
- Department of Bioinformatics & Structural Biochemistry, Institute of Biochemistry, Splaiul Independentei 296, 060031 Bucharest 17, Romania; (C.V.A.M.); (F.P.)
| | - Florin Pastrama
- Department of Bioinformatics & Structural Biochemistry, Institute of Biochemistry, Splaiul Independentei 296, 060031 Bucharest 17, Romania; (C.V.A.M.); (F.P.)
| | - N. Erwin Ivessa
- Center for Medical Biochemistry, Max Perutz Labs, Medical University of Vienna, A-1030 Vienna, Austria;
| | - Stefana M. Petrescu
- Department of Molecular Cell Biology, Institute of Biochemistry, Splaiul Independentei 296, 060031 Bucharest 17, Romania; (M.C.); (G.N.C.)
- Correspondence: ; Tel.: +40-2-1223-9069
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7
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Abstract
In consistent with other membrane-bound and secretory proteins, immune checkpoint proteins go through a set of modifications in the endoplasmic reticulum (ER) to acquire their native functional structures before they function at their destinations. There are various ER-resident chaperones and enzymes synergistically regulate and catalyze the glycosylation, folding and transporting of proteins. The whole processing is under the surveillance of ER quality control system which allows the correctly folded proteins to exit from the ER with the help of coat proteinII(COPII) coated vesicles, while retains the rest of terminally misfolded ones in the ER and then eliminates them via ER-associated degradation (ERAD) or ER-to-lysosomes-associated degradation (ERLAD). The dysfunction of the ER causes ER stress which triggers unfolded protein response (UPR) to restore ER proteostasis. Unsolvable prolonged ER stress ultimately results in cell death. This chapter reviews the process that proteins undergo in the ER, and the glycosylation, folding and degradation of immune checkpoint proteins as well as the associated potential immunotherapies to date.
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8
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Park S, Zuber C, Roth J. Selective autophagy of cytosolic protein aggregates involves ribosome-free rough endoplasmic reticulum. Histochem Cell Biol 2019; 153:89-99. [PMID: 31720797 DOI: 10.1007/s00418-019-01829-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/31/2019] [Indexed: 10/25/2022]
Abstract
Autophagy is a degradative cellular process that can be both non-selective and selective and begins with the formation of a unique smooth double-membrane phagophore which wraps around a portion of the cytoplasm. Excess and damaged organelles and cytoplasmic protein aggregates are degraded by selective autophagy. Previously, we reported that in fed HepG2 cells, cytoplasmic aggregates of EDEM1 and surplus fibrinogen Aα-γ assembly intermediates are targets of selective autophagy receptors and become degraded by a selective autophagy called aggrephagy. Here, we show by multiple confocal immunofluorescence and colocalization panels the codistribution of cytoplasmic protein aggregates with the selective autophagy receptors p62/SQSTM1 and NBR1 and with the phagophore marker LC3, and that phagophores induced by vinblastine treatment contain complexes of protein aggregates and selective autophagy receptors. By combined serial ultrathin section analysis and immunoelectron microscopy, we found that in fed HepG2 cells, a basically ribosome-free subdomain of rough endoplasmic reticulum (RER) cisternae forms a cradle that engulfs the cytoplasmic protein aggregates. This RER subdomain appears structurally different from omegasomes formed by the RER, which were suggested to provide a membrane platform from which the phagophore is derived in starvation-induced autophagy. Taken together, our observations provide further evidence for the importance of RER subdomains as a site and membrane source for phagophore formation and show their involvement in selective autophagy.
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Affiliation(s)
- Sujin Park
- Biozentrum, University of Basel, 4056, Basel, Switzerland.,Department of Integrated OMICS for Biomedical Science, WCU Program of Graduate School, Yonsei University, Seoul, 120-749, South Korea
| | - Christian Zuber
- Division of Cell and Molecular Pathology, Department of Pathology, University of Zurich, 8091, Zurich, Switzerland
| | - Jürgen Roth
- Department of Integrated OMICS for Biomedical Science, WCU Program of Graduate School, Yonsei University, Seoul, 120-749, South Korea. .,Division of Cell and Molecular Pathology, Department of Pathology, University of Zurich, 8091, Zurich, Switzerland.
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Kocaturk NM, Gozuacik D. Crosstalk Between Mammalian Autophagy and the Ubiquitin-Proteasome System. Front Cell Dev Biol 2018; 6:128. [PMID: 30333975 PMCID: PMC6175981 DOI: 10.3389/fcell.2018.00128] [Citation(s) in RCA: 270] [Impact Index Per Article: 45.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 09/13/2018] [Indexed: 12/16/2022] Open
Abstract
Autophagy and the ubiquitin-proteasome system (UPS) are the two major intracellular quality control and recycling mechanisms that are responsible for cellular homeostasis in eukaryotes. Ubiquitylation is utilized as a degradation signal by both systems, yet, different mechanisms are in play. The UPS is responsible for the degradation of short-lived proteins and soluble misfolded proteins whereas autophagy eliminates long-lived proteins, insoluble protein aggregates and even whole organelles (e.g., mitochondria, peroxisomes) and intracellular parasites (e.g., bacteria). Both the UPS and selective autophagy recognize their targets through their ubiquitin tags. In addition to an indirect connection between the two systems through ubiquitylated proteins, recent data indicate the presence of connections and reciprocal regulation mechanisms between these degradation pathways. In this review, we summarize these direct and indirect interactions and crosstalks between autophagy and the UPS, and their implications for cellular stress responses and homeostasis.
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Affiliation(s)
- Nur Mehpare Kocaturk
- Molecular Biology, Genetics and Bioengineering Program, Faculty of Engineering and Natural Sciences, Sabanci University, Istanbul, Turkey
| | - Devrim Gozuacik
- Molecular Biology, Genetics and Bioengineering Program, Faculty of Engineering and Natural Sciences, Sabanci University, Istanbul, Turkey
- Center of Excellence for Functional Surfaces and Interfaces for Nano Diagnostics (EFSUN), Sabanci University, Istanbul, Turkey
- Nanotechnology Research and Application Center (SUNUM), Sabanci University, Istanbul, Turkey
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10
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Nemec AA, Howell LA, Peterson AK, Murray MA, Tomko RJ. Autophagic clearance of proteasomes in yeast requires the conserved sorting nexin Snx4. J Biol Chem 2017; 292:21466-21480. [PMID: 29109144 DOI: 10.1074/jbc.m117.817999] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 11/03/2017] [Indexed: 11/06/2022] Open
Abstract
Turnover of the 26S proteasome by autophagy is an evolutionarily conserved process that governs cellular proteolytic capacity and eliminates inactive particles. In most organisms, proteasomes are located in both the nucleus and cytoplasm. However, the specific autophagy routes for nuclear and cytoplasmic proteasomes are unclear. Here, we investigate the spatial control of autophagic proteasome turnover in budding yeast (Saccharomyces cerevisiae). We found that nitrogen starvation-induced proteasome autophagy is independent of known nucleophagy pathways but is compromised when nuclear protein export is blocked. Furthermore, via pharmacological tethering of proteasomes to chromatin or the plasma membrane, we provide evidence that nuclear proteasomes at least partially disassemble before autophagic turnover, whereas cytoplasmic proteasomes remain largely intact. A targeted screen of autophagy genes identified a requirement for the conserved sorting nexin Snx4 in the autophagic turnover of proteasomes and several other large multisubunit complexes. We demonstrate that Snx4 cooperates with sorting nexins Snx41 and Snx42 to mediate proteasome turnover and is required for the formation of cytoplasmic proteasome puncta that accumulate when autophagosome formation is blocked. Together, our results support distinct mechanistic paths in the turnover of nuclear versus cytoplasmic proteasomes and point to a critical role for Snx4 in cytoplasmic agglomeration of proteasomes en route to autophagic destruction.
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Affiliation(s)
- Antonia A Nemec
- From the Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, Florida 32306
| | - Lauren A Howell
- From the Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, Florida 32306
| | - Anna K Peterson
- From the Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, Florida 32306
| | - Matthew A Murray
- From the Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, Florida 32306
| | - Robert J Tomko
- From the Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, Florida 32306
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11
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Raychaudhuri S, Espenshade PJ. Endoplasmic Reticulum Exit of Golgi-resident Defective for SREBP Cleavage (Dsc) E3 Ligase Complex Requires Its Activity. J Biol Chem 2015; 290:14430-40. [PMID: 25918164 DOI: 10.1074/jbc.m114.630863] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2014] [Indexed: 01/23/2023] Open
Abstract
Layers of quality control ensure proper protein folding and complex formation prior to exit from the endoplasmic reticulum. The fission yeast Dsc E3 ligase is a Golgi-localized complex required for sterol regulatory element-binding protein (SREBP) transcription factor activation that shows architectural similarity to endoplasmic reticulum-associated degradation E3 ligases. The Dsc E3 ligase consists of five integral membrane proteins (Dsc1-Dsc5) and functionally interacts with the conserved AAA-ATPase Cdc48. Utilizing an in vitro ubiquitination assay, we demonstrated that Dsc1 has ubiquitin E3 ligase activity that requires the E2 ubiquitin-conjugating enzyme Ubc4. Mutations that specifically block Dsc1-Ubc4 interaction prevent SREBP cleavage, indicating that SREBP activation requires Dsc E3 ligase activity. Surprisingly, Golgi localization of the Dsc E3 ligase complex also requires Dsc1 E3 ligase activity. Analysis of Dsc E3 ligase complex formation, glycosylation, and localization indicated that Dsc1 E3 ligase activity is specifically required for endoplasmic reticulum exit of the complex. These results define enzyme activity-dependent sorting as an autoregulatory mechanism for protein trafficking.
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Affiliation(s)
- Sumana Raychaudhuri
- From the Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Peter J Espenshade
- From the Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
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12
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Ferris SP, Kodali VK, Kaufman RJ. Glycoprotein folding and quality-control mechanisms in protein-folding diseases. Dis Model Mech 2015; 7:331-41. [PMID: 24609034 PMCID: PMC3944493 DOI: 10.1242/dmm.014589] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Biosynthesis of proteins – from translation to folding to export – encompasses a complex set of events that are exquisitely regulated and scrutinized to ensure the functional quality of the end products. Cells have evolved to capitalize on multiple post-translational modifications in addition to primary structure to indicate the folding status of nascent polypeptides to the chaperones and other proteins that assist in their folding and export. These modifications can also, in the case of irreversibly misfolded candidates, signal the need for dislocation and degradation. The current Review focuses on the glycoprotein quality-control (GQC) system that utilizes protein N-glycosylation and N-glycan trimming to direct nascent glycopolypeptides through the folding, export and dislocation pathways in the endoplasmic reticulum (ER). A diverse set of pathological conditions rooted in defective as well as over-vigilant ER quality-control systems have been identified, underlining its importance in human health and disease. We describe the GQC pathways and highlight disease and animal models that have been instrumental in clarifying our current understanding of these processes.
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Affiliation(s)
- Sean P Ferris
- Department of Biological Chemistry and Medical Scientist Training Program, University of Michigan, Ann Arbor, MI 48109, USA
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13
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Fisher E, Lake E, McLeod RS. Apolipoprotein B100 quality control and the regulation of hepatic very low density lipoprotein secretion. J Biomed Res 2014; 28:178-93. [PMID: 25013401 PMCID: PMC4085555 DOI: 10.7555/jbr.28.20140019] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Accepted: 02/15/2014] [Indexed: 12/19/2022] Open
Abstract
Apolipoprotein B (apoB) is the main protein component of very low density lipoprotein (VLDL) and is necessary for the assembly and secretion of these triglyceride (TG)-rich particles. Following release from the liver, VLDL is converted to low density lipoprotein (LDL) in the plasma and increased production of VLDL can therefore play a detrimental role in cardiovascular disease. Increasing evidence has helped to establish VLDL assembly as a target for the treatment of dyslipidemias. Multiple factors are involved in the folding of the apoB protein and the formation of a secretion-competent VLDL particle. Failed VLDL assembly can initiate quality control mechanisms in the hepatocyte that target apoB for degradation. ApoB is a substrate for endoplasmic reticulum associated degradation (ERAD) by the ubiquitin proteasome system and for autophagy. Efficient targeting and disposal of apoB is a regulated process that modulates VLDL secretion and partitioning of TG. Emerging evidence suggests that significant overlap exists between these degradative pathways. For example, the insulin-mediated targeting of apoB to autophagy and postprandial activation of the unfolded protein response (UPR) may employ the same cellular machinery and regulatory cues. Changes in the quality control mechanisms for apoB impact hepatic physiology and pathology states, including insulin resistance and fatty liver. Insulin signaling, lipid metabolism and the hepatic UPR may impact VLDL production, particularly during the postprandial state. In this review we summarize our current understanding of VLDL assembly, apoB degradation, quality control mechanisms and the role of these processes in liver physiology and in pathologic states.
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Affiliation(s)
- Eric Fisher
- Biochemistry & Molecular Biology, Faculty of Medicine, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Elizabeth Lake
- Biochemistry & Molecular Biology, Faculty of Medicine, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Roger S McLeod
- Biochemistry & Molecular Biology, Faculty of Medicine, Dalhousie University, Halifax, NS B3H 4R2, Canada
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Park S, Jang I, Zuber C, Lee Y, Cho JW, Matsuo I, Ito Y, Roth J. ERADication of EDEM1 occurs by selective autophagy and requires deglycosylation by cytoplasmic peptide N-glycanase. Histochem Cell Biol 2014; 142:153-69. [PMID: 24664425 DOI: 10.1007/s00418-014-1204-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/22/2014] [Indexed: 11/30/2022]
Abstract
ER degradation-enhancing α-mannosidase-like 1 protein (EDEM1) is involved in the routing of misfolded glycoproteins for degradation in the cytoplasm. Previously, we reported that EDEM1 leaves the endoplasmic reticulum via non-COPII vesicles (Zuber et al. in Proc Natl Acad Sci USA 104:4407-4412, 2007) and becomes degraded by basal autophagy (Le Fourn et al. in Cell Mol Life Sci 66:1434-1445, 2009). However, it is unknown which type of autophagy is involved. Likewise, how EDEM1 is targeted to autophagosomes remains elusive. We now show that EDEM1 is degraded by selective autophagy. It colocalizes with the selective autophagy cargo receptors p62/SQSTM1, neighbor of BRCA1 gene 1 (NBR1) and autophagy-linked FYVE (Alfy) protein, and becomes engulfed by autophagic isolation membranes. The interaction with p62/SQSTM1 and NBR1 is required for routing of EDEM1 to autophagosomes since it can be blocked by short inhibitory RNA knockdown of the cargo receptors. Furthermore, p62/SQSTM1 interacts only with deglycosylated EDEM1 that is also ubiquitinated. The deglycosylation of EDEM1 occurs by the cytosolic peptide N-glycanase and is a prerequisite for interaction and aggregate formation with p62/SQSTM1 as demonstrated by the effect of peptide N-glycanase inhibitors on the formation of protein aggregates. Conversely, aggregation of p62/SQSTM1 and EDEM1 occurs independent of cytoplasmic histone deacetylase. These data provide novel insight into the mechanism of autophagic degradation of the ER-associated protein degradation (ERAD) component EDEM1 and disclose hitherto unknown parallels with the clearance of cytoplasmic aggregates of misfolded proteins by selective autophagy.
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Affiliation(s)
- Sujin Park
- WCU Program, Department of Integrated OMICS for Biomedical Science, Yonsei University Graduate School, Seoul, 120-749, Korea
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Taatjes DJ. Cell biology of protein glycosylation: a celebration of the career of Jürgen Roth on the occasion of his 70th birthday. Cell Biol Int 2014; 38:547-52. [PMID: 24375674 DOI: 10.1002/cbin.10239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Accepted: 12/24/2013] [Indexed: 11/08/2022]
Affiliation(s)
- Douglas J Taatjes
- Department of Pathology and Microscopy Imaging Center, College of Medicine, University of Vermont, Burlington, Vermont, USA
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16
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Venditti R, Wilson C, De Matteis MA. Exiting the ER: what we know and what we don't. Trends Cell Biol 2013; 24:9-18. [PMID: 24076263 DOI: 10.1016/j.tcb.2013.08.005] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Revised: 08/07/2013] [Accepted: 08/13/2013] [Indexed: 01/17/2023]
Abstract
The vast majority of proteins that are transported to different cellular compartments and secreted from the cell require coat protein complex II (COPII) for export from the endoplasmic reticulum (ER). Many of the molecular mechanisms underlying COPII assembly are understood in great detail, but it is becoming increasingly evident that this basic machinery is insufficient to account for diverse aspects of protein export from the ER that are observed in vivo. Here we review recent data that have furthered our mechanistic understanding of COPII assembly and, in particular, how genetic diseases associated with the early secretory pathway have added fundamental insights into the regulation of ER-derived carrier formation. We also highlight some unresolved issues that future work should address to better understand the physiology of COPII-mediated transport.
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Affiliation(s)
- Rossella Venditti
- Telethon Institute of Genetics and Medicine, Via Pietro Castellino 111, Naples 80131, Italy
| | - Cathal Wilson
- Telethon Institute of Genetics and Medicine, Via Pietro Castellino 111, Naples 80131, Italy
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