1
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Tax G, Guay KP, Pantalone L, Ceci M, Soldà T, Hitchman CJ, Hill JC, Vasiljević S, Lia A, Modenutti CP, Straatman KR, Santino A, Molinari M, Zitzmann N, Hebert DN, Roversi P, Trerotola M. Rescue of secretion of rare-disease-associated misfolded mutant glycoproteins in UGGT1 knock-out mammalian cells. Traffic 2024; 25:e12927. [PMID: 38272446 PMCID: PMC10832616 DOI: 10.1111/tra.12927] [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: 06/02/2023] [Revised: 11/02/2023] [Accepted: 12/05/2023] [Indexed: 01/27/2024]
Abstract
Endoplasmic reticulum (ER) retention of misfolded glycoproteins is mediated by the ER-localized eukaryotic glycoprotein secretion checkpoint, UDP-glucose glycoprotein glucosyl-transferase (UGGT). The enzyme recognizes a misfolded glycoprotein and flags it for ER retention by re-glucosylating one of its N-linked glycans. In the background of a congenital mutation in a secreted glycoprotein gene, UGGT-mediated ER retention can cause rare disease, even if the mutant glycoprotein retains activity ("responsive mutant"). Using confocal laser scanning microscopy, we investigated here the subcellular localization of the human Trop-2-Q118E, E227K and L186P mutants, which cause gelatinous drop-like corneal dystrophy (GDLD). Compared with the wild-type Trop-2, which is correctly localized at the plasma membrane, these Trop-2 mutants are retained in the ER. We studied fluorescent chimeras of the Trop-2 Q118E, E227K and L186P mutants in mammalian cells harboring CRISPR/Cas9-mediated inhibition of the UGGT1 and/or UGGT2 genes. The membrane localization of the Trop-2 Q118E, E227K and L186P mutants was successfully rescued in UGGT1-/- cells. UGGT1 also efficiently reglucosylated Trop-2-Q118E-EYFP in cellula. The study supports the hypothesis that UGGT1 modulation would constitute a novel therapeutic strategy for the treatment of pathological conditions associated to misfolded membrane glycoproteins (whenever the mutation impairs but does not abrogate function), and it encourages the testing of modulators of ER glycoprotein folding quality control as broad-spectrum rescue-of-secretion drugs in rare diseases caused by responsive secreted glycoprotein mutants.
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Affiliation(s)
- Gabor Tax
- Leicester Institute of Chemical and Structural Biology and Department of Molecular and Cell Biology, University of Leicester, Henry Wellcome Building, Lancaster Road, Leicester LE1 7HR, England, United Kingdom
| | - Kevin P. Guay
- Department of Biochemistry and Molecular Biology, and Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, United States
| | - Ludovica Pantalone
- Department of Medical, Oral and Biotechnological Sciences, "G. d'Annunzio" University of Chieti-Pescara, Italy; Laboratory of Cancer Pathology, Center for Advanced Studies and Technology (CAST), "G. d'Annunzio" University of Chieti-Pescara, Italy
| | - Martina Ceci
- Department of Medical, Oral and Biotechnological Sciences, "G. d'Annunzio" University of Chieti-Pescara, Italy; Laboratory of Cancer Pathology, Center for Advanced Studies and Technology (CAST), "G. d'Annunzio" University of Chieti-Pescara, Italy
| | - Tatiana Soldà
- Institute for Research in Biomedicine, Faculty of Biomedical Sciences, UniversitàdellaSvizzeraItaliana (USI), Bellinzona, Switzerland
| | - Charlie J. Hitchman
- Leicester Institute of Chemical and Structural Biology and Department of Molecular and Cell Biology, University of Leicester, Henry Wellcome Building, Lancaster Road, Leicester LE1 7HR, England, United Kingdom
| | - Johan C. Hill
- Institute of Glycobiology, Department of Biochemistry, South Parks Road, Oxford OX1 3RQ, United Kingdom
| | - Snežana Vasiljević
- Institute of Glycobiology, Department of Biochemistry, South Parks Road, Oxford OX1 3RQ, United Kingdom
| | - Andrea Lia
- Leicester Institute of Chemical and Structural Biology and Department of Molecular and Cell Biology, University of Leicester, Henry Wellcome Building, Lancaster Road, Leicester LE1 7HR, England, United Kingdom
- Institute of Sciences of Food Production, ISPA-CNR Unit of Lecce, via Monteroni, I-73100 Lecce, Italy
| | - Carlos P. Modenutti
- Departamento de QuímicaBiológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires (FCEyN-UBA) e Instituto de QuímicaBiológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN) CONICET, Pabellón 2 de Ciudad Universitaria, Ciudad de Buenos Aires C1428EHA, Argentina
| | - Kees R. Straatman
- Core Biotechnology Services, University of Leicester, University Road, Leicester LE1 7RH, England, United Kingdom
| | - Angelo Santino
- Institute of Sciences of Food Production, ISPA-CNR Unit of Lecce, via Monteroni, I-73100 Lecce, Italy
| | - Maurizio Molinari
- Institute of Glycobiology, Department of Biochemistry, South Parks Road, Oxford OX1 3RQ, United Kingdom
- School of Life Sciences, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Nicole Zitzmann
- Institute of Glycobiology, Department of Biochemistry, South Parks Road, Oxford OX1 3RQ, United Kingdom
| | - Daniel N. Hebert
- Department of Biochemistry and Molecular Biology, and Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, United States
| | - Pietro Roversi
- Leicester Institute of Chemical and Structural Biology and Department of Molecular and Cell Biology, University of Leicester, Henry Wellcome Building, Lancaster Road, Leicester LE1 7HR, England, United Kingdom
- Institute of AgriculturalBiology and Biotecnology, IBBA-CNR Unit of Milano, via Bassini 15, I-20133 Milano, Italy
| | - Marco Trerotola
- Department of Medical, Oral and Biotechnological Sciences, "G. d'Annunzio" University of Chieti-Pescara, Italy; Laboratory of Cancer Pathology, Center for Advanced Studies and Technology (CAST), "G. d'Annunzio" University of Chieti-Pescara, Italy
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2
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Guay KP, Ke H, Canniff NP, George GT, Eyles SJ, Mariappan M, Contessa JN, Gershenson A, Gierasch LM, Hebert DN. ER chaperones use a protein folding and quality control glyco-code. Mol Cell 2023; 83:4524-4537.e5. [PMID: 38052210 PMCID: PMC10790639 DOI: 10.1016/j.molcel.2023.11.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Revised: 10/18/2023] [Accepted: 11/07/2023] [Indexed: 12/07/2023]
Abstract
N-glycans act as quality control tags by recruiting lectin chaperones to assist protein maturation in the endoplasmic reticulum. The location and composition of N-glycans (glyco-code) are key to the chaperone-selection process. Serpins, a class of serine protease inhibitors, fold non-sequentially to achieve metastable active states. Here, the role of the glyco-code in assuring successful maturation and quality control of two human serpins, alpha-1 antitrypsin (AAT) and antithrombin III (ATIII), is described. We find that AAT, which has glycans near its N terminus, is assisted by early lectin chaperone binding. In contrast, ATIII, which has more C-terminal glycans, is initially helped by BiP and then later by lectin chaperones mediated by UGGT reglucosylation. UGGT action is increased for misfolding-prone disease variants, and these clients are preferentially glucosylated on their most C-terminal glycan. Our study illustrates how serpins utilize N-glycan presence, position, and composition to direct their proper folding, quality control, and trafficking.
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Affiliation(s)
- Kevin P Guay
- Department of Biochemistry and Molecular Biology, University of Massachusetts Amherst, Amherst, MA, USA; Program in Molecular and Cellular Biology, University of Massachusetts Amherst, Amherst, MA, USA
| | - Haiping Ke
- Department of Biochemistry and Molecular Biology, University of Massachusetts Amherst, Amherst, MA, USA
| | - Nathan P Canniff
- Department of Biochemistry and Molecular Biology, University of Massachusetts Amherst, Amherst, MA, USA; Program in Molecular and Cellular Biology, University of Massachusetts Amherst, Amherst, MA, USA
| | - Gracie T George
- Department of Biochemistry and Molecular Biology, University of Massachusetts Amherst, Amherst, MA, USA
| | - Stephen J Eyles
- Department of Biochemistry and Molecular Biology, University of Massachusetts Amherst, Amherst, MA, USA; Program in Molecular and Cellular Biology, University of Massachusetts Amherst, Amherst, MA, USA; Institute for Applied Life Sciences, Mass Spectrometry Center, University of Massachusetts Amherst, Amherst, MA, USA
| | - Malaiyalam Mariappan
- Department of Cell Biology, Nanobiology Institute, Yale School of Medicine, West Haven, CT, USA
| | - Joseph N Contessa
- Departments of Therapeutic Radiology and Pharmacology, Yale School of Medicine, New Haven, CT, USA
| | - Anne Gershenson
- Department of Biochemistry and Molecular Biology, University of Massachusetts Amherst, Amherst, MA, USA; Program in Molecular and Cellular Biology, University of Massachusetts Amherst, Amherst, MA, USA
| | - Lila M Gierasch
- Department of Biochemistry and Molecular Biology, University of Massachusetts Amherst, Amherst, MA, USA; Program in Molecular and Cellular Biology, University of Massachusetts Amherst, Amherst, MA, USA; Department of Chemistry, University of Massachusetts Amherst, Amherst, MA, USA
| | - Daniel N Hebert
- Department of Biochemistry and Molecular Biology, University of Massachusetts Amherst, Amherst, MA, USA; Program in Molecular and Cellular Biology, University of Massachusetts Amherst, Amherst, MA, USA.
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3
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Miura K, Katsuki R, Yoshida S, Ohta R, Tamura T. Identification of EGF Receptor and Thrombospondin-1 as Endogenous Targets of ER-Associated Degradation Enhancer EDEM1 in HeLa Cells. Int J Mol Sci 2023; 24:12171. [PMID: 37569550 PMCID: PMC10418772 DOI: 10.3390/ijms241512171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Revised: 07/26/2023] [Accepted: 07/27/2023] [Indexed: 08/13/2023] Open
Abstract
Secretory and membrane proteins are vital for cell activities, including intra- and intercellular communication. Therefore, protein quality control in the endoplasmic reticulum (ER) is an essential and crucial process for eukaryotic cells. Endoplasmic reticulum-associated degradation (ERAD) targets misfolded proteins during the protein maturation process in the ER and leads to their disposal. This process maintains the ER productive function and prevents misfolded protein stress (i.e., ER stress). The ERAD-stimulating factor ER degradation-enhancing α mannosidase-like 1 protein (EDEM1) acts on misfolded proteins to accelerate ERAD, thereby maintaining the productivity of the ER. However, the detail mechanism underlying the function of EDEM1 in ERAD is not completely understood due to a lack of established physiological substrate proteins. In this study, we attempted to identify substrate proteins for EDEM1 using siRNA. The matrix component thrombospondin-1 (TSP1) and epidermal growth factor receptor (EGFR) were identified as candidate targets of EDEM1. Their protein maturation status and cellular localization were markedly affected by knockdown of EDEM1. We also showed that EDEM1 physically associates with EGFR and enhances EGFR degradation via ERAD. Our data highlight the physiological role of EDEM1 in maintaining specific target proteins and provide a potential approach to the regulation of expression of clinically important proteins.
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Affiliation(s)
- Kohta Miura
- Department of Life Science, Graduate School of Engineering Science, Akita University, Akita 010-8502, Japan
| | - Riko Katsuki
- Department of Life Science, Graduate School of Engineering Science, Akita University, Akita 010-8502, Japan
| | - Shusei Yoshida
- Department of Life Science, Faculty of Engineering Science, Akita University, Akita 010-8502, Japan
| | - Ren Ohta
- Department of Life Science, Graduate School of Engineering Science, Akita University, Akita 010-8502, Japan
| | - Taku Tamura
- Department of Life Science, Graduate School of Engineering Science, Akita University, Akita 010-8502, Japan
- Department of Life Science, Faculty of Engineering Science, Akita University, Akita 010-8502, Japan
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4
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Tax G, Guay KP, Soldà T, Hitchman CJ, Hill JC, Vasiljević S, Lia A, Modenutti CP, Straatman KR, Santino A, Molinari M, Zitzmann N, Hebert DN, Roversi P, Trerotola M. Rescue of secretion of a rare-disease associated mis-folded mutant glycoprotein in UGGT1 knock-out mammalian cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.30.542711. [PMID: 37398215 PMCID: PMC10312515 DOI: 10.1101/2023.05.30.542711] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Endoplasmic reticulum (ER) retention of mis-folded glycoproteins is mediated by the ERlocalised eukaryotic glycoprotein secretion checkpoint, UDP-glucose glycoprotein glucosyl-transferase (UGGT). The enzyme recognises a mis-folded glycoprotein and flags it for ER retention by reglucosylating one of its N-linked glycans. In the background of a congenital mutation in a secreted glycoprotein gene, UGGT-mediated ER retention can cause rare disease even if the mutant glycoprotein retains activity ("responsive mutant"). Here, we investigated the subcellular localisation of the human Trop-2 Q118E variant, which causes gelatinous droplike corneal dystrophy (GDLD). Compared with the wild type Trop-2, which is correctly localised at the plasma membrane, the Trop-2-Q118E variant is found to be heavily retained in the ER. Using Trop-2-Q118E, we tested UGGT modulation as a rescue-of-secretion therapeutic strategy for congenital rare disease caused by responsive mutations in genes encoding secreted glycoproteins. We investigated secretion of a EYFP-fusion of Trop-2-Q118E by confocal laser scanning microscopy. As a limiting case of UGGT inhibition, mammalian cells harbouring CRISPR/Cas9-mediated inhibition of the UGGT1 and/or UGGT2 gene expressions were used. The membrane localisation of the Trop-2-Q118E-EYFP mutant was successfully rescued in UGGT1-/- and UGGT1/2-/- cells. UGGT1 also efficiently reglucosylated Trop-2-Q118E-EYFP in cellula. The study supports the hypothesis that UGGT1 modulation constitutes a novel therapeutic strategy for the treatment of Trop-2-Q118E associated GDLD, and it encourages the testing of modulators of ER glycoprotein folding Quality Control (ERQC) as broad-spectrum rescueof-secretion drugs in rare diseases caused by responsive secreted glycoprotein mutants.
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Affiliation(s)
- Gábor Tax
- Leicester Institute of Chemical and Structural Biology and Department of Molecular and Cell Biology, University of Leicester, Henry Wellcome Building, Lancaster Road, Leicester LE1 7HR, England, United Kingdom
| | - Kevin P. Guay
- Department of Biochemistry and Molecular Biology, and Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, United States
| | - Tatiana Soldà
- Institute for Research in Biomedicine, Faculty of Biomedical Sciences, Università della Svizzera Italiana (USI), Bellinzona, Switzerland
| | - Charlie J. Hitchman
- Leicester Institute of Chemical and Structural Biology and Department of Molecular and Cell Biology, University of Leicester, Henry Wellcome Building, Lancaster Road, Leicester LE1 7HR, England, United Kingdom
| | - Johan C. Hill
- Institute of Glycobiology, Department of Biochemistry, South Parks Road, Oxford OX1 3RQ, United Kingdom
| | - Snežana Vasiljević
- Institute of Glycobiology, Department of Biochemistry, South Parks Road, Oxford OX1 3RQ, United Kingdom
| | - Andrea Lia
- Leicester Institute of Chemical and Structural Biology and Department of Molecular and Cell Biology, University of Leicester, Henry Wellcome Building, Lancaster Road, Leicester LE1 7HR, England, United Kingdom
- Institute of Sciences of Food Production, ISPA-CNR Unit of Lecce, via Monteroni, I-73100 Lecce, Italy
| | - Carlos P. Modenutti
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires (FCEyN-UBA) e Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN) CONICET, Pabellón 2 de Ciudad Universitaria, Ciudad de Buenos Aires C1428EHA, Argentina
| | - Kees R. Straatman
- Leicester Institute of Chemical and Structural Biology and Department of Molecular and Cell Biology, University of Leicester, Henry Wellcome Building, Lancaster Road, Leicester LE1 7HR, England, United Kingdom
- Core Biotechnology Services, University of Leicester, University Road, Leicester LE1 7RH, England, United Kingdom
| | - Angelo Santino
- Institute of Sciences of Food Production, ISPA-CNR Unit of Lecce, via Monteroni, I-73100 Lecce, Italy
| | - Maurizio Molinari
- Institute of Glycobiology, Department of Biochemistry, South Parks Road, Oxford OX1 3RQ, United Kingdom
- School of Life Sciences, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Nicole Zitzmann
- Institute of Glycobiology, Department of Biochemistry, South Parks Road, Oxford OX1 3RQ, United Kingdom
| | - Daniel N. Hebert
- Department of Biochemistry and Molecular Biology, and Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, United States
| | - Pietro Roversi
- Leicester Institute of Chemical and Structural Biology and Department of Molecular and Cell Biology, University of Leicester, Henry Wellcome Building, Lancaster Road, Leicester LE1 7HR, England, United Kingdom
- Institute of Agricultural Biology and Biotecnology, IBBACNR Unit of Milano, via Bassini 15, I-20133 Milano, Italy
| | - Marco Trerotola
- Department of Medical, Oral and Biotechnological Sciences, “G. d’Annunzio” University of Chieti-Pescara, Italy; Laboratory of Cancer Pathology, Center for Advanced Studies and Technology (CAST), “G. d’Annunzio” University of Chieti-Pescara, Italy
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5
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Calnexin, More Than Just a Molecular Chaperone. Cells 2023; 12:cells12030403. [PMID: 36766745 PMCID: PMC9913998 DOI: 10.3390/cells12030403] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 01/17/2023] [Accepted: 01/17/2023] [Indexed: 01/26/2023] Open
Abstract
Calnexin is a type I integral endoplasmic reticulum (ER) membrane protein with an N-terminal domain that resides in the lumen of the ER and a C-terminal domain that extends into the cytosol. Calnexin is commonly referred to as a molecular chaperone involved in the folding and quality control of membrane-associated and secreted proteins, a function that is attributed to its ER- localized domain with a structure that bears a strong resemblance to another luminal ER chaperone and Ca2+-binding protein known as calreticulin. Studies have discovered that the cytosolic C-terminal domain of calnexin undergoes distinct post-translational modifications and interacts with a variety of proteins. Here, we discuss recent findings and hypothesize that the post-translational modifications of the calnexin C-terminal domain and its interaction with specific cytosolic proteins play a role in coordinating ER functions with events taking place in the cytosol and other cellular compartments.
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Chambers JE, Zubkov N, Kubánková M, Nixon-Abell J, Mela I, Abreu S, Schwiening M, Lavarda G, López-Duarte I, Dickens JA, Torres T, Kaminski CF, Holt LJ, Avezov E, Huntington JA, George-Hyslop PS, Kuimova MK, Marciniak SJ. Z-α 1-antitrypsin polymers impose molecular filtration in the endoplasmic reticulum after undergoing phase transition to a solid state. SCIENCE ADVANCES 2022; 8:eabm2094. [PMID: 35394846 PMCID: PMC8993113 DOI: 10.1126/sciadv.abm2094] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 02/16/2022] [Indexed: 05/06/2023]
Abstract
Misfolding of secretory proteins in the endoplasmic reticulum (ER) features in many human diseases. In α1-antitrypsin deficiency, the pathogenic Z variant aberrantly assembles into polymers in the hepatocyte ER, leading to cirrhosis. We show that α1-antitrypsin polymers undergo a liquid:solid phase transition, forming a protein matrix that retards mobility of ER proteins by size-dependent molecular filtration. The Z-α1-antitrypsin phase transition is promoted during ER stress by an ATF6-mediated unfolded protein response. Furthermore, the ER chaperone calreticulin promotes Z-α1-antitrypsin solidification and increases protein matrix stiffness. Single-particle tracking reveals that solidification initiates in cells with normal ER morphology, previously assumed to represent a healthy pool. We show that Z-α1-antitrypsin-induced hypersensitivity to ER stress can be explained by immobilization of ER chaperones within the polymer matrix. This previously unidentified mechanism of ER dysfunction provides a template for understanding a diverse group of related proteinopathies and identifies ER chaperones as potential therapeutic targets.
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Affiliation(s)
- Joseph E. Chambers
- Cambridge Institute for Medical Research (CIMR), Department of Medicine, University of Cambridge, The Keith Peters Building, Hills Road, Cambridge CB2 0XY, UK
| | - Nikita Zubkov
- Cambridge Institute for Medical Research (CIMR), Department of Medicine, University of Cambridge, The Keith Peters Building, Hills Road, Cambridge CB2 0XY, UK
| | - Markéta Kubánková
- Department of Chemistry, Imperial College London, Wood Lane, London W12 0BZ, UK
| | - Jonathon Nixon-Abell
- Cambridge Institute for Medical Research (CIMR), Department of Medicine, University of Cambridge, The Keith Peters Building, Hills Road, Cambridge CB2 0XY, UK
| | - Ioanna Mela
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Philippa Fawcett Drive, Cambridge CB3 0AS, UK
| | - Susana Abreu
- Cambridge Institute for Medical Research (CIMR), Department of Medicine, University of Cambridge, The Keith Peters Building, Hills Road, Cambridge CB2 0XY, UK
| | - Max Schwiening
- Cambridge Institute for Medical Research (CIMR), Department of Medicine, University of Cambridge, The Keith Peters Building, Hills Road, Cambridge CB2 0XY, UK
| | - Giulia Lavarda
- Departamento de Química Orgánica and Institute for Advanced Research in Chemical Sciences (IAdChem), Universidad Autónoma de Madrid, Madrid 28049, Spain
| | - Ismael López-Duarte
- Departamento de Química Orgánica and Institute for Advanced Research in Chemical Sciences (IAdChem), Universidad Autónoma de Madrid, Madrid 28049, Spain
| | - Jennifer A. Dickens
- Cambridge Institute for Medical Research (CIMR), Department of Medicine, University of Cambridge, The Keith Peters Building, Hills Road, Cambridge CB2 0XY, UK
| | - Tomás Torres
- Departamento de Química Orgánica and Institute for Advanced Research in Chemical Sciences (IAdChem), Universidad Autónoma de Madrid, Madrid 28049, Spain
- IMDEA Nanociencia, Campus de Cantoblanco, Madrid 28049, Spain
| | - Clemens F. Kaminski
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Philippa Fawcett Drive, Cambridge CB3 0AS, UK
| | - Liam J. Holt
- Institute for Systems Genetics, New York University Grossman School of Medicine, 435 E 30th St, New York, NY 10016, USA
| | - Edward Avezov
- Department of Clinical Neurosciences and UK Dementia Research Institute, University of Cambridge, Cambridge CB2 0AH, UK
| | - James A. Huntington
- Cambridge Institute for Medical Research (CIMR), Department of Medicine, University of Cambridge, The Keith Peters Building, Hills Road, Cambridge CB2 0XY, UK
| | - Peter St George-Hyslop
- Cambridge Institute for Medical Research (CIMR), Department of Medicine, University of Cambridge, The Keith Peters Building, Hills Road, Cambridge CB2 0XY, UK
- Department of Medicine (Neurology), Temerty Faculty of Medicine, University of Toronto, University Health Network, Toronto, ON M5T 0S8, Canada
- Taub Institute For Research on Alzheimer’s Disease and the Ageing Brain, Department of Neurology, Columbia University Irvine Medical Center, 630 West 1/68 Street, New York, NY 10032, USA
| | - Marina K. Kuimova
- Department of Chemistry, Imperial College London, Wood Lane, London W12 0BZ, UK
| | - Stefan J. Marciniak
- Cambridge Institute for Medical Research (CIMR), Department of Medicine, University of Cambridge, The Keith Peters Building, Hills Road, Cambridge CB2 0XY, UK
- Royal Papworth Hospital, Cambridge CB2 0AY, UK
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7
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Domesticated LTR-Retrotransposon gag-Related Gene (Gagr) as a Member of the Stress Response Network in Drosophila. Life (Basel) 2022; 12:life12030364. [PMID: 35330115 PMCID: PMC8956099 DOI: 10.3390/life12030364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Revised: 02/27/2022] [Accepted: 02/27/2022] [Indexed: 11/24/2022] Open
Abstract
The most important sources of new components of genomes are transposable elements, which can occupy more than half of the nucleotide sequence of the genome in higher eukaryotes. Among the mobile components of a genome, a special place is occupied by retroelements, which are similar to retroviruses in terms of their mechanisms of integration into a host genome. The process of positive selection of certain sequences of transposable elements and retroviruses in a host genome is commonly called molecular domestication. There are many examples of evolutionary adaptations of gag (retroviral capsid) sequences as new regulatory sequences of different genes in mammals, where domesticated gag genes take part in placenta functioning and embryogenesis, regulation of apoptosis, hematopoiesis, and metabolism. The only gag-related gene has been found in the Drosophila genome—Gagr. According to the large-scale transcriptomic and proteomic analysis data, the Gagr gene in D. melanogaster is a component of the protein complex involved in the stress response. In this work, we consider the evolutionary processes that led to the formation of a new function of the domesticated gag gene and its adaptation to participation in the stress response. We discuss the possible functional role of the Gagr as part of the complex with its partners in Drosophila, and the pathway of evolution of proteins of the complex in eukaryotes to determine the benefit of the domesticated retroelement gag gene.
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8
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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: 18] [Impact Index Per Article: 6.0] [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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9
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Role and mechanism of chaperones calreticulin and ERP57 in restoring trafficking to mutant HERG‑A561V protein. Int J Mol Med 2021; 48:159. [PMID: 34212985 PMCID: PMC8262656 DOI: 10.3892/ijmm.2021.4992] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 05/20/2021] [Indexed: 02/06/2023] Open
Abstract
Long QT syndrome type 2 is caused by a mutation in the human‑ether‑a‑go‑go‑related gene (HERG) gene encoding the rapidly activating delayed rectifier K‑current. HERG is a key cell membrane glycoprotein; however, whether the maturation process of HERG protein involves key molecules derived from the calnexin (CNX)/calreticulin (CRT) cycle and how these molecules work remains unknown. Using western blotting, the present study screened the key molecules CNX/CRT/endoplasmic reticulum protein 57 (ERP57) involved in this cycle, and it was revealed that the protein expression levels of CNX/CRT/ERP57 in wild‑type (WT)/A561V cells were increased compared with those in WT cells (n=3; P<0.05). Additionally, a co‑immunoprecipitation experiment was used to reveal that the ability of CNX/ERP57/CRT to interact with HERG was significantly increased in A561V and WT/A561V cells (n=3; P<0.05). A plasmid lacking the bb' domain of ERP57 was constructed and it was demonstrated that the key site of ERP57 binding to CRT and immature HERG protein is the bb' domain. The whole‑cell patch‑clamp technique detected that the tail current density increased by 46% following overexpression of CRT and by 53% following overexpression of ERP57 in WT/A561V cells. Overexpression of CRT and ERP57 could increased HERG protein levels on the membrane detected by confocal imaging. Furthermore, overexpression of ERP57 and CRT proteins could restore the HERG‑A561V mutant protein trafficking process and rescue the dominant‑negative suppression of WT. Overall, ERP57/CRT served a crucial role in the HERG‑A561V mutant protein trafficking deficiency and degradation process.
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10
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Brown AI, Koslover EF. Design principles for the glycoprotein quality control pathway. PLoS Comput Biol 2021; 17:e1008654. [PMID: 33524026 PMCID: PMC7877790 DOI: 10.1371/journal.pcbi.1008654] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 02/11/2021] [Accepted: 12/21/2020] [Indexed: 01/11/2023] Open
Abstract
Newly-translated glycoproteins in the endoplasmic reticulum (ER) often undergo cycles of chaperone binding and release in order to assist in folding. Quality control is required to distinguish between proteins that have completed native folding, those that have yet to fold, and those that have misfolded. Using quantitative modeling, we explore how the design of the quality-control pathway modulates its efficiency. Our results show that an energy-consuming cyclic quality-control process, similar to the observed physiological system, outperforms alternative designs. The kinetic parameters that optimize the performance of this system drastically change with protein production levels, while remaining relatively insensitive to the protein folding rate. Adjusting only the degradation rate, while fixing other parameters, allows the pathway to adapt across a range of protein production levels, aligning with in vivo measurements that implicate the release of degradation-associated enzymes as a rapid-response system for perturbations in protein homeostasis. The quantitative models developed here elucidate design principles for effective glycoprotein quality control in the ER, improving our mechanistic understanding of a system crucial to maintaining cellular health. We explore the architecture and limitations of the quality-control pathway responsible for efficient folding of secretory proteins. Newly-synthesized proteins are tagged by the attachment of a ‘glycan’ sugar chain which facilitates their binding to a chaperone that assists protein folding. Removal of a specific sugar group on the glycan ends the interaction with the chaperone, and not-yet-folded proteins can be re-tagged for another round of chaperone binding. A degradation pathway acts in parallel with the folding cycle, to remove those proteins that have remained unfolded for a sufficiently long time. We develop and solve a mathematical model of this quality-control system, showing that the cyclical design found in living cells is uniquely able to maximize folded protein throughput while avoiding accumulation of unfolded proteins. Although this physiological model provides the best performance, its parameters must be adjusted to perform optimally under different protein production loads, and any single fixed set of parameters leads to poor performance when production rate is altered. We find that a single adjustable parameter, the protein degradation rate, is sufficient to allow optimal performance across a range of conditions. Interestingly, observations of living cells suggest that the degradation speed is indeed rapidly adjusted.
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Affiliation(s)
- Aidan I. Brown
- Department of Physics, University of California, San Diego, San Diego, California, United States of America
| | - Elena F. Koslover
- Department of Physics, University of California, San Diego, San Diego, California, United States of America
- * E-mail:
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11
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Abstract
Folding of proteins is essential so that they can exert their functions. For proteins that transit the secretory pathway, folding occurs in the endoplasmic reticulum (ER) and various chaperone systems assist in acquiring their correct folding/subunit formation. N-glycosylation is one of the most conserved posttranslational modification for proteins, and in eukaryotes it occurs in the ER. Consequently, eukaryotic cells have developed various systems that utilize N-glycans to dictate and assist protein folding, or if they consistently fail to fold properly, to destroy proteins for quality control and the maintenance of homeostasis of proteins in the ER.
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12
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Adams BM, Canniff NP, Guay KP, Larsen ISB, Hebert DN. Quantitative glycoproteomics reveals cellular substrate selectivity of the ER protein quality control sensors UGGT1 and UGGT2. eLife 2020; 9:e63997. [PMID: 33320095 PMCID: PMC7771966 DOI: 10.7554/elife.63997] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 12/14/2020] [Indexed: 12/13/2022] Open
Abstract
UDP-glucose:glycoprotein glucosyltransferase (UGGT) 1 and 2 are central hubs in the chaperone network of the endoplasmic reticulum (ER), acting as gatekeepers to the early secretory pathway, yet little is known about their cellular clients. These two quality control sensors control lectin chaperone binding and glycoprotein egress from the ER. A quantitative glycoproteomics strategy was deployed to identify cellular substrates of the UGGTs at endogenous levels in CRISPR-edited HEK293 cells. The 71 UGGT substrates identified were mainly large multidomain and heavily glycosylated proteins when compared to the general N-glycoproteome. UGGT1 was the dominant glucosyltransferase with a preference toward large plasma membrane proteins whereas UGGT2 favored the modification of smaller, soluble lysosomal proteins. This study sheds light on differential specificities and roles of UGGT1 and UGGT2 and provides insight into the cellular reliance on the carbohydrate-dependent chaperone system to facilitate proper folding and maturation of the cellular N-glycoproteome.
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Affiliation(s)
- Benjamin M Adams
- Department of Biochemistry and Molecular Biology, University of MassachusettsAmherstUnited States
- Program in Molecular and Cellular Biology, University of MassachusettsAmherstUnited States
| | - Nathan P Canniff
- Department of Biochemistry and Molecular Biology, University of MassachusettsAmherstUnited States
- Program in Molecular and Cellular Biology, University of MassachusettsAmherstUnited States
| | - Kevin P Guay
- Department of Biochemistry and Molecular Biology, University of MassachusettsAmherstUnited States
- Program in Molecular and Cellular Biology, University of MassachusettsAmherstUnited States
| | - Ida Signe Bohse Larsen
- Department of Cellular and Molecular Medicine, University of CopenhagenCopenhagenDenmark
- Copenhagen Center for Glycomics, University of CopenhagenCopenhagenDenmark
| | - Daniel N Hebert
- Department of Biochemistry and Molecular Biology, University of MassachusettsAmherstUnited States
- Program in Molecular and Cellular Biology, University of MassachusettsAmherstUnited States
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13
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Rellmann Y, Eidhof E, Dreier R. Review: ER stress-induced cell death in osteoarthritic cartilage. Cell Signal 2020; 78:109880. [PMID: 33307190 DOI: 10.1016/j.cellsig.2020.109880] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 12/03/2020] [Accepted: 12/04/2020] [Indexed: 12/16/2022]
Abstract
In cartilage, chondrocytes are responsible for the biogenesis and maintenance of the extracellular matrix (ECM) composed of proteins, glycoproteins and proteoglycans. Various cellular stresses, such as hypoxia, nutrient deprivation, oxidative stress or the accumulation of advanced glycation end products (AGEs) during aging, but also translational errors or mutations in cartilage components or chaperone proteins affect the synthesis and secretion of ECM proteins, causing protein aggregates to accumulate in the endoplasmic reticulum (ER). This condition, referred to as ER stress, interferes with cartilage cell homeostasis and initiates the unfolded protein response (UPR), a rescue mechanism to regain cell viability and function. Chronic or irreversible ER stress, however, triggers UPR-initiated cell death. Due to unresolved ER stress in chondrocytes, diseases of the skeletal system, such as chondrodysplasias, arise. ER stress has also been identified as a contributing factor to the pathogenesis of cartilage degeneration processes such as osteoarthritis (OA). This review provides current knowledge about the biogenesis of ECM components in chondrocytes, describes possible causes for the impairment of involved processes and focuses on the ER stress-induced cell death in articular cartilage during OA. Targeting of the ER stress itself or intervention in UPR signaling to reduce death of chondrocytes may be promising for future osteoarthritis therapy.
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Affiliation(s)
- Yvonne Rellmann
- Institute of Physiological Chemistry and Pathobiochemistry, Waldeyerstraße 15, 48149 Münster, Germany
| | - Elco Eidhof
- Institute of Physiological Chemistry and Pathobiochemistry, Waldeyerstraße 15, 48149 Münster, Germany
| | - Rita Dreier
- Institute of Physiological Chemistry and Pathobiochemistry, Waldeyerstraße 15, 48149 Münster, Germany.
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14
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Margolin E, Oh YJ, Verbeek M, Naude J, Ponndorf D, Meshcheriakova YA, Peyret H, van Diepen MT, Chapman R, Meyers AE, Lomonossoff GP, Matoba N, Williamson A, Rybicki EP. Co-expression of human calreticulin significantly improves the production of HIV gp140 and other viral glycoproteins in plants. PLANT BIOTECHNOLOGY JOURNAL 2020; 18:2109-2117. [PMID: 32096288 PMCID: PMC7540014 DOI: 10.1111/pbi.13369] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 02/10/2020] [Accepted: 02/17/2020] [Indexed: 05/19/2023]
Abstract
Plant molecular farming (PMF) is rapidly gaining traction as a viable alternative to the currently accepted paradigm of producing biologics. While the platform is potentially cheaper and more scalable than conventional manufacturing systems, expression yields and appropriate post-translational modifications along the plant secretory pathway remain a challenge for certain proteins. Viral fusion glycoproteins in particular are often expressed at low yields in plants and, in some cases, may not be appropriately processed. Recently, however, transiently or stably engineering the host plant has shown promise as a strategy for producing heterologous proteins with more complex maturation requirements. In this study we investigated the co-expression of a suite of human chaperones to improve the production of a human immunodeficiency virus (HIV) type 1 soluble gp140 vaccine candidate in Nicotiana benthamiana plants. The co-expression of calreticulin (CRT) resulted in a dramatic increase in Env expression and ameliorated the endoplasmic reticulum (ER) stress response - as evidenced by lower transcript abundance of representative stress-responsive genes. The co-expression of CRT similarly improved accumulation of glycoproteins from Epstein-Barr virus (EBV), Rift Valley fever virus (RVFV) and chikungunya virus (CHIKV), suggesting that the endogenous chaperone machinery may impose a bottleneck for their production. We subsequently successfully combined the co-expression of human CRT with the transient expression of human furin, to enable the production of an appropriately cleaved HIV gp140 antigen. These transient plant host engineering strategies are a promising approach for the production of high yields of appropriately processed and cleaved viral glycoproteins.
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Affiliation(s)
- Emmanuel Margolin
- Division of Medical VirologyDepartment of PathologyFaculty of Health SciencesUniversity of Cape TownCape TownSouth Africa
- Wellcome Trust Centre for Infectious Disease Research in AfricaUniversity of Cape TownCape TownSouth Africa
- Faculty of Health SciencesInstitute of Infectious Disease and Molecular MedicineUniversity of Cape TownCape TownSouth Africa
- Biopharming Research UnitDepartment of Molecular and Cell BiologyUniversity of Cape TownCape TownSouth Africa
| | - Youngjun J. Oh
- Department of Pharmacology and ToxicologyUniversity of Louisville School of MedicineLouisvilleKYUSA
| | - Matthew Verbeek
- Biopharming Research UnitDepartment of Molecular and Cell BiologyUniversity of Cape TownCape TownSouth Africa
| | - Jason Naude
- Biopharming Research UnitDepartment of Molecular and Cell BiologyUniversity of Cape TownCape TownSouth Africa
| | - Daniel Ponndorf
- Department of Biological ChemistryJohn Innes CentreNorwichUK
| | | | - Hadrien Peyret
- Department of Biological ChemistryJohn Innes CentreNorwichUK
| | - Michiel T. van Diepen
- Division of Medical VirologyDepartment of PathologyFaculty of Health SciencesUniversity of Cape TownCape TownSouth Africa
- Faculty of Health SciencesInstitute of Infectious Disease and Molecular MedicineUniversity of Cape TownCape TownSouth Africa
| | - Ros Chapman
- Division of Medical VirologyDepartment of PathologyFaculty of Health SciencesUniversity of Cape TownCape TownSouth Africa
- Faculty of Health SciencesInstitute of Infectious Disease and Molecular MedicineUniversity of Cape TownCape TownSouth Africa
| | - Ann E. Meyers
- Biopharming Research UnitDepartment of Molecular and Cell BiologyUniversity of Cape TownCape TownSouth Africa
| | | | - Nobuyuki Matoba
- Department of Pharmacology and ToxicologyUniversity of Louisville School of MedicineLouisvilleKYUSA
| | - Anna‐Lise Williamson
- Division of Medical VirologyDepartment of PathologyFaculty of Health SciencesUniversity of Cape TownCape TownSouth Africa
- Wellcome Trust Centre for Infectious Disease Research in AfricaUniversity of Cape TownCape TownSouth Africa
- Faculty of Health SciencesInstitute of Infectious Disease and Molecular MedicineUniversity of Cape TownCape TownSouth Africa
| | - Edward P. Rybicki
- Faculty of Health SciencesInstitute of Infectious Disease and Molecular MedicineUniversity of Cape TownCape TownSouth Africa
- Biopharming Research UnitDepartment of Molecular and Cell BiologyUniversity of Cape TownCape TownSouth Africa
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15
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Adams BM, Ke H, Gierasch LM, Gershenson A, Hebert DN. Proper secretion of the serpin antithrombin relies strictly on thiol-dependent quality control. J Biol Chem 2019; 294:18992-19011. [PMID: 31662433 DOI: 10.1074/jbc.ra119.010450] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 10/24/2019] [Indexed: 01/04/2023] Open
Abstract
The protein quality control machinery of the endoplasmic reticulum (ERQC) ensures that client proteins are properly folded. ERQC substrates may be recognized as nonnative by the presence of exposed hydrophobic surfaces, free thiols, or processed N-glycans. How these features dictate which ERQC pathways engage a given substrate is poorly understood. Here, using metabolic labeling, immunoprecipitations, various biochemical assays, and the human serpin antithrombin III (ATIII) as a model, we explored the role of ERQC systems in mammalian cells. Although ATIII has N-glycans and a hydrophobic core, we found that its quality control depended solely on free thiol content. Mutagenesis of all six Cys residues in ATIII to Ala resulted in its efficient secretion even though the product was not natively folded. ATIII variants with free thiols were retained in the endoplasmic reticulum but not degraded. These results provide insight into the hierarchy of ERQC systems and reveal a fundamental vulnerability of ERQC in a case of reliance on the thiol-dependent quality control pathway.
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Affiliation(s)
- Benjamin M Adams
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, Massachusetts 01003.,Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, Massachusetts 01003
| | - Haiping Ke
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, Massachusetts 01003
| | - Lila M Gierasch
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, Massachusetts 01003.,Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, Massachusetts 01003.,Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003
| | - Anne Gershenson
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, Massachusetts 01003.,Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, Massachusetts 01003
| | - Daniel N Hebert
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, Massachusetts 01003 .,Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, Massachusetts 01003
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16
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Abstract
The site of protein folding and maturation for the majority of proteins that are secreted, localized to the plasma membrane or targeted to endomembrane compartments is the endoplasmic reticulum (ER). It is essential that proteins targeted to the ER are properly folded in order to carry out their function, as well as maintain protein homeostasis, as accumulation of misfolded proteins could lead to the formation of cytotoxic aggregates. Because protein folding is an error-prone process, the ER contains protein quality control networks that act to optimize proper folding and trafficking of client proteins. If a protein is unable to reach its native state, it is targeted for ER retention and subsequent degradation. The protein quality control networks of the ER that oversee this evaluation or interrogation process that decides the fate of maturing nascent chains is comprised of three general types of families: the classical chaperones, the carbohydrate-dependent system, and the thiol-dependent system. The cooperative action of these families promotes protein quality control and protein homeostasis in the ER. This review will describe the families of the ER protein quality control network and discuss the functions of individual members.
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Affiliation(s)
- Benjamin M Adams
- Department of Biochemistry and Molecular Biology, University of Massachusetts, 240 Thatcher Road, Amherst, MA, 01003, USA
- Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, MA, 01003, USA
| | - Michela E Oster
- Department of Biochemistry and Molecular Biology, University of Massachusetts, 240 Thatcher Road, Amherst, MA, 01003, USA
| | - Daniel N Hebert
- Department of Biochemistry and Molecular Biology, University of Massachusetts, 240 Thatcher Road, Amherst, MA, 01003, USA.
- Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, MA, 01003, USA.
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17
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Graham JB, Canniff NP, Hebert DN. TPR-containing proteins control protein organization and homeostasis for the endoplasmic reticulum. Crit Rev Biochem Mol Biol 2019; 54:103-118. [PMID: 31023093 DOI: 10.1080/10409238.2019.1590305] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The endoplasmic reticulum (ER) is a complex, multifunctional organelle comprised of a continuous membrane and lumen that is organized into a number of functional regions. It plays various roles including protein translocation, folding, quality control, secretion, calcium signaling, and lipid biogenesis. Cellular protein homeostasis is maintained by a complicated chaperone network, and the largest functional family within this network consists of proteins containing tetratricopeptide repeats (TPRs). TPRs are well-studied structural motifs that mediate intermolecular protein-protein interactions, supporting interactions with a wide range of ligands or substrates. Seven TPR-containing proteins have thus far been shown to localize to the ER and control protein organization and homeostasis within this multifunctional organelle. Here, we discuss the roles of these proteins in controlling ER processes and organization. The crucial roles that TPR-containing proteins play in the ER are highlighted by diseases or defects associated with their mutation or disruption.
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Affiliation(s)
- Jill B Graham
- a Molecular Cellular Biology Program , University of Massachusetts , Amherst , MA , USA.,b Biochemistry and Molecular Biology Department , University of Massachusetts , Amherst , MA , USA
| | - Nathan P Canniff
- a Molecular Cellular Biology Program , University of Massachusetts , Amherst , MA , USA.,b Biochemistry and Molecular Biology Department , University of Massachusetts , Amherst , MA , USA
| | - Daniel N Hebert
- a Molecular Cellular Biology Program , University of Massachusetts , Amherst , MA , USA.,b Biochemistry and Molecular Biology Department , University of Massachusetts , Amherst , MA , USA
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18
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Abstract
The endoplasmic reticulum (ER) is the site of maturation for roughly one-third of all cellular proteins. ER-resident molecular chaperones and folding catalysts promote folding and assembly in a diverse set of newly synthesized proteins. Because these processes are error-prone, all eukaryotic cells have a quality-control system in place that constantly monitors the proteins and decides their fate. Proteins with potentially harmful nonnative conformations are subjected to assisted folding or degraded. Persistent folding-defective proteins are distinguished from folding intermediates and targeted for degradation by a specific process involving clearance from the ER. Although the basic principles of these processes appear conserved from yeast to animals and plants, there are distinct differences in the ER-associated degradation of misfolded glycoproteins. The general importance of ER quality-control events is underscored by their involvement in the biogenesis of diverse cell surface receptors and their crucial maintenance of protein homeostasis under diverse stress conditions.
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Affiliation(s)
- Richard Strasser
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, 1190 Vienna, Austria;
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19
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Abstract
The endoplasmic reticulum (ER) is the site of maturation for roughly one-third of all cellular proteins. ER-resident molecular chaperones and folding catalysts promote folding and assembly in a diverse set of newly synthesized proteins. Because these processes are error-prone, all eukaryotic cells have a quality-control system in place that constantly monitors the proteins and decides their fate. Proteins with potentially harmful nonnative conformations are subjected to assisted folding or degraded. Persistent folding-defective proteins are distinguished from folding intermediates and targeted for degradation by a specific process involving clearance from the ER. Although the basic principles of these processes appear conserved from yeast to animals and plants, there are distinct differences in the ER-associated degradation of misfolded glycoproteins. The general importance of ER quality-control events is underscored by their involvement in the biogenesis of diverse cell surface receptors and their crucial maintenance of protein homeostasis under diverse stress conditions.
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Affiliation(s)
- Richard Strasser
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, 1190 Vienna, Austria;
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20
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Interdomain conformational flexibility underpins the activity of UGGT, the eukaryotic glycoprotein secretion checkpoint. Proc Natl Acad Sci U S A 2017; 114:8544-8549. [PMID: 28739903 DOI: 10.1073/pnas.1703682114] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Glycoproteins traversing the eukaryotic secretory pathway begin life in the endoplasmic reticulum (ER), where their folding is surveyed by the 170-kDa UDP-glucose:glycoprotein glucosyltransferase (UGGT). The enzyme acts as the single glycoprotein folding quality control checkpoint: it selectively reglucosylates misfolded glycoproteins, promotes their association with ER lectins and associated chaperones, and prevents premature secretion from the ER. UGGT has long resisted structural determination and sequence-based domain boundary prediction. Questions remain on how this single enzyme can flag misfolded glycoproteins of different sizes and shapes for ER retention and how it can span variable distances between the site of misfold and a glucose-accepting N-linked glycan on the same glycoprotein. Here, crystal structures of a full-length eukaryotic UGGT reveal four thioredoxin-like (TRXL) domains arranged in a long arc that terminates in two β-sandwiches tightly clasping the glucosyltransferase domain. The fold of the molecule is topologically complex, with the first β-sandwich and the fourth TRXL domain being encoded by nonconsecutive stretches of sequence. In addition to the crystal structures, a 15-Å cryo-EM reconstruction reveals interdomain flexibility of the TRXL domains. Double cysteine point mutants that engineer extra interdomain disulfide bridges rigidify the UGGT structure and exhibit impaired activity. The intrinsic flexibility of the TRXL domains of UGGT may therefore endow the enzyme with the promiscuity needed to recognize and reglucosylate its many different substrates and/or enable reglucosylation of N-linked glycans situated at variable distances from the site of misfold.
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21
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Protein quality control at the endoplasmic reticulum. Essays Biochem 2017; 60:227-235. [PMID: 27744338 DOI: 10.1042/ebc20160003] [Citation(s) in RCA: 103] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 05/31/2016] [Indexed: 12/22/2022]
Abstract
The ER (endoplasmic reticulum) is the protein folding 'factory' of the secretory pathway. Virtually all proteins destined for the plasma membrane, the extracellular space or other secretory compartments undergo folding and maturation within the ER. The ER hosts a unique PQC (protein quality control) system that allows specialized modifications such as glycosylation and disulfide bond formation essential for the correct folding and function of many secretory proteins. It is also the major checkpoint for misfolded or aggregation-prone proteins that may be toxic to the cell or extracellular environment. A failure of this system, due to aging or other factors, has therefore been implicated in a number of serious human diseases. In this article, we discuss several key features of ER PQC that maintain the health of the cellular secretome.
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22
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Calles-Garcia D, Yang M, Soya N, Melero R, Ménade M, Ito Y, Vargas J, Lukacs GL, Kollman JM, Kozlov G, Gehring K. Single-particle electron microscopy structure of UDP-glucose:glycoprotein glucosyltransferase suggests a selectivity mechanism for misfolded proteins. J Biol Chem 2017; 292:11499-11507. [PMID: 28490633 DOI: 10.1074/jbc.m117.789495] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Revised: 05/07/2017] [Indexed: 11/06/2022] Open
Abstract
The enzyme UDP-glucose:glycoprotein glucosyltransferase (UGGT) mediates quality control of glycoproteins in the endoplasmic reticulum by attaching glucose to N-linked glycan of misfolded proteins. As a sensor, UGGT ensures that misfolded proteins are recognized by the lectin chaperones and do not leave the secretory pathway. The structure of UGGT and the mechanism of its selectivity for misfolded proteins have been unknown for 25 years. Here, we used negative-stain electron microscopy and small-angle X-ray scattering to determine the structure of UGGT from Drosophila melanogaster at 18-Å resolution. Three-dimensional reconstructions revealed a cage-like structure with a large central cavity. Particle classification revealed flexibility that precluded determination of a high-resolution structure. Introduction of biotinylation sites into a fungal UGGT expressed in Escherichia coli allowed identification of the catalytic and first thioredoxin-like domains. We also used hydrogen-deuterium exchange mass spectrometry to map the binding site of an accessory protein, Sep15, to the first thioredoxin-like domain. The UGGT structural features identified suggest that the central cavity contains the catalytic site and is lined with hydrophobic surfaces. This enhances the binding of misfolded substrates with exposed hydrophobic residues and excludes folded proteins with hydrophilic surfaces. In conclusion, we have determined the UGGT structure, which enabled us to develop a plausible functional model of the mechanism for UGGT's selectivity for misfolded glycoproteins.
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Affiliation(s)
- Daniel Calles-Garcia
- From the Department of Biochemistry, McGill University, Montreal, Quebec H3G0B1, Canada
| | - Meng Yang
- From the Department of Biochemistry, McGill University, Montreal, Quebec H3G0B1, Canada
| | - Naoto Soya
- Department of Physiology, McGill University, Montreal, Quebec H3G1Y6, Canada
| | - Roberto Melero
- Biocomputing Unit, Centro Nacional de Biotectnologíay, 28049 Madrid, Spain
| | - Marie Ménade
- From the Department of Biochemistry, McGill University, Montreal, Quebec H3G0B1, Canada
| | - Yukishige Ito
- Synthetic Cellular Chemistry Laboratory, RIKEN, Wako, Saitama 351-0198, Japan
| | - Javier Vargas
- Biocomputing Unit, Centro Nacional de Biotectnologíay, 28049 Madrid, Spain.,Bioengineering Lab, Escuela Politécnica Superior, Universidad San Pablo CEU, 28668 Madrid, Spain, and
| | - Gergely L Lukacs
- Department of Physiology, McGill University, Montreal, Quebec H3G1Y6, Canada
| | - Justin M Kollman
- Department of Biochemistry, University of Washington, Seattle, Washington 98195-7350
| | - Guennadi Kozlov
- From the Department of Biochemistry, McGill University, Montreal, Quebec H3G0B1, Canada
| | - Kalle Gehring
- From the Department of Biochemistry, McGill University, Montreal, Quebec H3G0B1, Canada,
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23
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Abstract
The endoplasmic reticulum is the port of entry for proteins into the secretory pathway and the site of synthesis for several important lipids, including cholesterol, triacylglycerol, and phospholipids. Protein production within the endoplasmic reticulum is tightly regulated by a cohort of resident machinery that coordinates the folding, modification, and deployment of secreted and integral membrane proteins. Proteins failing to attain their native conformation are degraded through the endoplasmic reticulum-associated degradation (ERAD) pathway via a series of tightly coupled steps: substrate recognition, dislocation, and ubiquitin-dependent proteasomal destruction. The same ERAD machinery also controls the flux through various metabolic pathways by coupling the turnover of metabolic enzymes to the levels of key metabolites. We review the current understanding and biological significance of ERAD-mediated regulation of lipid metabolism in mammalian cells.
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Affiliation(s)
- Julian Stevenson
- Program in Metabolic Biology, Department of Nutritional Sciences and Toxicology, University of California, Berkeley, California 94720;
| | - Edmond Y Huang
- Program in Metabolic Biology, Department of Nutritional Sciences and Toxicology, University of California, Berkeley, California 94720;
| | - James A Olzmann
- Program in Metabolic Biology, Department of Nutritional Sciences and Toxicology, University of California, Berkeley, California 94720;
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24
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Abstract
Protein glycosylation is an essential co- and post-translational modification of secretory and membrane proteins in all eukaryotes. The initial steps of N-glycosylation and N-glycan processing are highly conserved between plants, mammals and yeast. In contrast, late N-glycan maturation steps in the Golgi differ significantly in plants giving rise to complex N-glycans with β1,2-linked xylose, core α1,3-linked fucose and Lewis A-type structures. While the essential role of N-glycan modifications on distinct mammalian glycoproteins is already well documented, we have only begun to decipher the biological function of this ubiquitous protein modification in different plant species. In this review, I focus on the biosynthesis and function of different protein N-linked glycans in plants. Special emphasis is given on glycan-mediated quality control processes in the ER and on the biological role of characteristic complex N-glycan structures.
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Affiliation(s)
- Richard Strasser
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna, Muthgasse 18, 1190 Vienna, Austria
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25
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Lamriben L, Graham JB, Adams BM, Hebert DN. N-Glycan-based ER Molecular Chaperone and Protein Quality Control System: The Calnexin Binding Cycle. Traffic 2016; 17:308-26. [PMID: 26676362 DOI: 10.1111/tra.12358] [Citation(s) in RCA: 121] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Revised: 12/14/2015] [Accepted: 12/14/2015] [Indexed: 12/17/2022]
Abstract
Helenius and colleagues proposed over 20-years ago a paradigm-shifting model for how chaperone binding in the endoplasmic reticulum was mediated and controlled for a new type of molecular chaperone- the carbohydrate-binding chaperones, calnexin and calreticulin. While the originally established basics for this lectin chaperone binding cycle holds true today, there has been a number of important advances that have expanded our understanding of its mechanisms of action, role in protein homeostasis, and its connection to disease states that are highlighted in this review.
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Affiliation(s)
- Lydia Lamriben
- Department of Biochemistry and Molecular Biology, Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, MA, 01003, USA
| | - Jill B Graham
- Department of Biochemistry and Molecular Biology, Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, MA, 01003, USA
| | - Benjamin M Adams
- Department of Biochemistry and Molecular Biology, Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, MA, 01003, USA
| | - Daniel N Hebert
- Department of Biochemistry and Molecular Biology, Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, MA, 01003, USA
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26
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Shao S, Hegde RS. Target Selection during Protein Quality Control. Trends Biochem Sci 2015; 41:124-137. [PMID: 26628391 DOI: 10.1016/j.tibs.2015.10.007] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Revised: 10/18/2015] [Accepted: 10/20/2015] [Indexed: 11/25/2022]
Abstract
Protein quality control (QC) pathways survey the cellular proteome to selectively recognize and degrade faulty proteins whose accumulation can lead to various diseases. Recognition of the occasional aberrant protein among an abundant sea of similar normal counterparts poses a considerable challenge to the cell. Solving this problem requires protein QC machinery to assay multiple molecular criteria within a spatial and temporal context. Although each QC pathway has unique criteria and mechanisms for distinguishing right from wrong, they appear to share several general concepts. We discuss principles of high-fidelity target recognition, the decisive event of all protein QC pathways, to guide future work in this area.
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Affiliation(s)
- Sichen Shao
- Medical Research Council Laboratory of Molecular Biology, Cambridge CB2 0QH, UK.
| | - Ramanujan S Hegde
- Medical Research Council Laboratory of Molecular Biology, Cambridge CB2 0QH, UK.
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27
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Caramelo JJ, Parodi AJ. A sweet code for glycoprotein folding. FEBS Lett 2015; 589:3379-87. [PMID: 26226420 DOI: 10.1016/j.febslet.2015.07.021] [Citation(s) in RCA: 90] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 07/15/2015] [Accepted: 07/15/2015] [Indexed: 12/11/2022]
Abstract
Glycoprotein synthesis is initiated in the endoplasmic reticulum (ER) lumen upon transfer of a glycan (Glc3Man9GlcNAc2) from a lipid derivative to Asn residues (N-glycosylation). N-Glycan-dependent quality control of glycoprotein folding in the ER prevents exit to Golgi of folding intermediates, irreparably misfolded glycoproteins and incompletely assembled multimeric complexes. It also enhances folding efficiency by preventing aggregation and facilitating formation of proper disulfide bonds. The control mechanism essentially involves four components, resident lectin-chaperones (calnexin and calreticulin) that recognize monoglucosylated polymannose protein-linked glycans, lectin-associated oxidoreductase acting on monoglucosylated glycoproteins (ERp57), a glucosyltransferase that creates monoglucosylated epitopes in protein-linked glycans (UGGT) and a glucosidase (GII) that removes the glucose units added by UGGT. This last enzyme is the only mechanism component sensing glycoprotein conformations as it creates monoglucosylated glycans exclusively in not properly folded glycoproteins or in not completely assembled multimeric glycoprotein complexes. Glycoproteins that fail to properly fold are eventually driven to proteasomal degradation in the cytosol following the ER-associated degradation pathway, in which the extent of N-glycan demannosylation by ER mannosidases play a relevant role in the identification of irreparably misfolded glycoproteins.
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Affiliation(s)
- Julio J Caramelo
- Fundación Instituto Leloir and Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA-CONICET), Avda. Patricias Argentinas 435, Buenos Aires C1405BWE, Argentina.
| | - Armando J Parodi
- Fundación Instituto Leloir and Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA-CONICET), Avda. Patricias Argentinas 435, Buenos Aires C1405BWE, Argentina.
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28
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Tannous A, Pisoni GB, Hebert DN, Molinari M. N-linked sugar-regulated protein folding and quality control in the ER. Semin Cell Dev Biol 2015; 41:79-89. [PMID: 25534658 PMCID: PMC4474783 DOI: 10.1016/j.semcdb.2014.12.001] [Citation(s) in RCA: 181] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Accepted: 12/02/2014] [Indexed: 11/18/2022]
Abstract
Asparagine-linked glycans (N-glycans) are displayed on the majority of proteins synthesized in the endoplasmic reticulum (ER). Removal of the outermost glucose residue recruits the lectin chaperone malectin possibly involved in a first triage of defective polypeptides. Removal of a second glucose promotes engagement of folding and quality control machineries built around the ER lectin chaperones calnexin (CNX) and calreticulin (CRT) and including oxidoreductases and peptidyl-prolyl isomerases. Deprivation of the last glucose residue dictates the release of N-glycosylated polypeptides from the lectin chaperones. Correctly folded proteins are authorized to leave the ER. Non-native polypeptides are recognized by the ER quality control key player UDP-glucose glycoprotein glucosyltransferase 1 (UGT1), re-glucosylated and re-addressed to the CNX/CRT chaperone binding cycle to provide additional opportunity for the protein to fold in the ER. Failure to attain the native structure determines the selection of the misfolded polypeptides for proteasome-mediated degradation.
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Affiliation(s)
- Abla Tannous
- Department of Biochemistry and Molecular Biology, Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, MA 01003, USA
| | | | - Daniel N Hebert
- Department of Biochemistry and Molecular Biology, Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, MA 01003, USA.
| | - Maurizio Molinari
- Università della Svizzera italiana, CH-6900 Lugano, Switzerland; Institute for Research in Biomedicine, Protein Folding and Quality Control, CH-6500 Bellinzona, Switzerland; Ecole Polytechnique Fédérale de Lausanne, School of Life Sciences, CH-1015 Lausanne, Switzerland.
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