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Orsi A, van Anken E, Vitale M, Zamai M, Caiolfa VR, Sitia R, Bakunts A. Congress of multiple dimers is needed for cross-phosphorylation of IRE1α and its RNase activity. Life Sci Alliance 2024; 7:e202302562. [PMID: 38886017 PMCID: PMC11184514 DOI: 10.26508/lsa.202302562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Revised: 05/24/2024] [Accepted: 06/03/2024] [Indexed: 06/20/2024] Open
Abstract
The unfolded protein response can switch from a pro-survival to a maladaptive, pro-apoptotic mode. During ER stress, IRE1α sensors dimerize, become phosphorylated, and activate XBP1 splicing, increasing folding capacity in the ER protein factory. The steps that turn on the IRE1α endonuclease activity against endogenous mRNAs during maladaptive ER stress are still unknown. Here, we show that although necessary, IRE1α dimerization is not sufficient to trigger phosphorylation. Random and/or guided collisions among IRE1α dimers are needed to elicit cross-phosphorylation and endonuclease activities. Thus, reaching a critical concentration of IRE1α dimers in the ER membrane is a key event. Formation of stable IRE1α clusters is not necessary for RNase activity. However, clustering could modulate the potency of the response, promoting interactions between dimers and decreasing the accessibility of phosphorylated IRE1α to phosphatases. The stepwise activation of IRE1α molecules and their low concentration at the steady state prevent excessive responses, unleashing full-blown IRE1 activity only upon intense stress conditions.
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Affiliation(s)
- Andrea Orsi
- Division of Genetics and Cell Biology, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Eelco van Anken
- https://ror.org/01gmqr298 Division of Genetics and Cell Biology, Vita-Salute San Raffaele University, Milan, Italy
| | - Milena Vitale
- https://ror.org/01gmqr298 Division of Genetics and Cell Biology, Vita-Salute San Raffaele University, Milan, Italy
| | - Moreno Zamai
- Unit of Microscopy and Dynamic Imaging, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
| | - Valeria R Caiolfa
- Unit of Microscopy and Dynamic Imaging, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
- Center for Experimental Imaging, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Roberto Sitia
- https://ror.org/01gmqr298 Division of Genetics and Cell Biology, Vita-Salute San Raffaele University, Milan, Italy
| | - Anush Bakunts
- https://ror.org/01gmqr298 Division of Genetics and Cell Biology, Vita-Salute San Raffaele University, Milan, Italy
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2
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Hendershot LM, Buck TM, Brodsky JL. The Essential Functions of Molecular Chaperones and Folding Enzymes in Maintaining Endoplasmic Reticulum Homeostasis. J Mol Biol 2024; 436:168418. [PMID: 38143019 DOI: 10.1016/j.jmb.2023.168418] [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: 10/16/2023] [Revised: 12/18/2023] [Accepted: 12/19/2023] [Indexed: 12/26/2023]
Abstract
It has been estimated that up to one-third of the proteins encoded by the human genome enter the endoplasmic reticulum (ER) as extended polypeptide chains where they undergo covalent modifications, fold into their native structures, and assemble into oligomeric protein complexes. The fidelity of these processes is critical to support organellar, cellular, and organismal health, and is perhaps best underscored by the growing number of disease-causing mutations that reduce the fidelity of protein biogenesis in the ER. To meet demands encountered by the diverse protein clientele that mature in the ER, this organelle is populated with a cadre of molecular chaperones that prevent protein aggregation, facilitate protein disulfide isomerization, and lower the activation energy barrier of cis-trans prolyl isomerization. Components of the lectin (glycan-binding) chaperone system also reside within the ER and play numerous roles during protein biogenesis. In addition, the ER houses multiple homologs of select chaperones that can recognize and act upon diverse peptide signatures. Moreover, redundancy helps ensure that folding-compromised substrates are unable to overwhelm essential ER-resident chaperones and enzymes. In contrast, the ER in higher eukaryotic cells possesses a single member of the Hsp70, Hsp90, and Hsp110 chaperone families, even though several homologs of these molecules reside in the cytoplasm. In this review, we discuss specific functions of the many factors that maintain ER quality control, highlight some of their interactions, and describe the vulnerabilities that arise from the absence of multiple members of some chaperone families.
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Affiliation(s)
- Linda M Hendershot
- Department of Tumor Cell Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, United States.
| | - Teresa M Buck
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, United States
| | - Jeffrey L Brodsky
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, United States
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3
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Simpson MS, De Luca H, Cauthorn S, Luong P, Udeshi ND, Svinkina T, Schmieder SS, Carr SA, Grey MJ, Lencer WI. IRE1α recognizes a structural motif in cholera toxin to activate an unfolded protein response. J Cell Biol 2024; 223:e202402062. [PMID: 38578285 PMCID: PMC10996581 DOI: 10.1083/jcb.202402062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 03/18/2024] [Accepted: 03/20/2024] [Indexed: 04/06/2024] Open
Abstract
IRE1α is an endoplasmic reticulum (ER) sensor that recognizes misfolded proteins to induce the unfolded protein response (UPR). We studied cholera toxin (CTx), which invades the ER and activates IRE1α in host cells, to understand how unfolded proteins are recognized. Proximity labeling colocalized the enzymatic and metastable A1 segment of CTx (CTxA1) with IRE1α in live cells, where we also found that CTx-induced IRE1α activation enhanced toxicity. In vitro, CTxA1 bound the IRE1α lumenal domain (IRE1αLD), but global unfolding was not required. Rather, the IRE1αLD recognized a seven-residue motif within an edge β-strand of CTxA1 that must locally unfold for binding. Binding mapped to a pocket on IRE1αLD normally occupied by a segment of the IRE1α C-terminal flexible loop implicated in IRE1α oligomerization. Mutation of the CTxA1 recognition motif blocked CTx-induced IRE1α activation in live cells, thus linking the binding event with IRE1α signal transduction and induction of the UPR.
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Affiliation(s)
- Mariska S. Simpson
- Division of Gastroenterology, Hepatology and Nutrition, Boston Children’s Hospital, Boston MA, USA
- Graduate School of Life Sciences, Utrecht University, Utrecht, Netherlands
| | - Heidi De Luca
- Division of Gastroenterology, Hepatology and Nutrition, Boston Children’s Hospital, Boston MA, USA
| | - Sarah Cauthorn
- Division of Gastroenterology, Hepatology and Nutrition, Boston Children’s Hospital, Boston MA, USA
- Division of Gastroenterology, Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - Phi Luong
- Division of Gastroenterology, Hepatology and Nutrition, Boston Children’s Hospital, Boston MA, USA
| | | | | | - Stefanie S. Schmieder
- Division of Gastroenterology, Hepatology and Nutrition, Boston Children’s Hospital, Boston MA, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA, USA
| | | | - Michael J. Grey
- Division of Gastroenterology, Hepatology and Nutrition, Boston Children’s Hospital, Boston MA, USA
- Division of Gastroenterology, Beth Israel Deaconess Medical Center, Boston, MA, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA, USA
- Harvard Digestive Disease Center, Boston, MA, USA
| | - Wayne I. Lencer
- Division of Gastroenterology, Hepatology and Nutrition, Boston Children’s Hospital, Boston MA, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA, USA
- Harvard Digestive Disease Center, Boston, MA, USA
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4
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Pick T, Gamayun I, Tinschert R, Cavalié A. Kinetics of the thapsigargin-induced Ca2+ mobilisation: A quantitative analysis in the HEK-293 cell line. Front Physiol 2023; 14:1127545. [PMID: 37051019 PMCID: PMC10083721 DOI: 10.3389/fphys.2023.1127545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Accepted: 03/07/2023] [Indexed: 03/29/2023] Open
Abstract
Thapsigargin (TG) inhibits the sarco/endoplasmic reticulum Ca2+ ATPase (SERCA) pump and, when applied acutely, it initiates a Ca2+ mobilisation that begins with the loss of Ca2+ from the endoplasmic reticulum (ER) and culminates with store-operated Ca2+ entry (SOCE) from the extracellular space. Using the popular model cell line HEK-293, we quantified TG-induced changes in cytosolic and ER Ca2+ levels using FURA-2 and the FRET-based ER Ca2+ sensor D1ER, respectively. Our analysis predicts an ER Ca2+ leak of 5–6 µM⋅s−1 for the typical basal ER Ca2+ level of 335–407 µM in HEK-293 cells. The resulting cytosolic Ca2+ transients reached peak amplitudes of 0.6–1.0 µM in the absence of external Ca2+ and were amplified by SOCE that amounted to 28–30 nM⋅s−1 in 1 mM external Ca2+. Additionally, cytosolic Ca2+ transients were shaped by a Ca2+ clearance of 10–13 nM⋅s−1. Using puromycin (PURO), which enhances the ER Ca2+ leak, we show that TG-induced cytosolic Ca2+ transients are directly related to ER Ca2+ levels and to the ER Ca2+ leak. A one-compartment model incorporating ER Ca2+ leak and cytosolic Ca2+ clearance accounted satisfactorily for the basic features of TG-induced Ca2+ transients and underpinned the rule that an increase in amplitude associated with shortening of TG-induced cytosolic Ca2+ transients most likely reflects an increase in ER Ca2+ leak.
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Affiliation(s)
- Tillman Pick
- *Correspondence: Tillman Pick, ; Adolfo Cavalié,
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5
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Ambrose AJ, Sivinski J, Zerio CJ, Zhu X, Godek J, Kumirov VK, Coma Brujas T, Torra Garcia J, Annadurai A, Schmidlin CJ, Werner A, Shi T, Zavareh RB, Lairson L, Zhang DD, Chapman E. Discovery and Development of a Selective Inhibitor of the ER Resident Chaperone Grp78. J Med Chem 2023; 66:677-694. [PMID: 36516003 DOI: 10.1021/acs.jmedchem.2c01631] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
A recent study illustrated that a fluorescence polarization assay can be used to identify substrate-competitive Hsp70 inhibitors that can be isoform-selective. Herein, we use that assay in a moderate-throughput screen and report the discovery of a druglike amino-acid-based inhibitor with reasonable specificity for the endoplasmic reticular Hsp70, Grp78. Using traditional medicinal chemistry approaches, the potency and selectivity were further optimized through structure-activity relationship (SAR) studies in parallel assays for six of the human Hsp70 isoforms. The top compounds were all tested against a panel of cancer cell lines and disappointingly showed little effect. The top-performing compound, 8, was retested using a series of endoplasmic reticulum (ER) stress-inducing agents and found to synergize with these agents. Finally, 8 was tested in a spheroid tumor model and found to be more potent than in two-dimensional models. The optimized Grp78 inhibitors are the first reported isoform-selective small-molecule-competitive inhibitors of an Hsp70-substrate interaction.
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Affiliation(s)
- Andrew J Ambrose
- Department of Pharmacology and Toxicology, R. Ken Coit College of Pharmacy, University of Arizona, Tucson, Arizona85721, United States
| | - Jared Sivinski
- Department of Pharmacology and Toxicology, R. Ken Coit College of Pharmacy, University of Arizona, Tucson, Arizona85721, United States
| | - Christopher J Zerio
- Department of Pharmacology and Toxicology, R. Ken Coit College of Pharmacy, University of Arizona, Tucson, Arizona85721, United States
| | - Xiaoyi Zhu
- Department of Pharmacology and Toxicology, R. Ken Coit College of Pharmacy, University of Arizona, Tucson, Arizona85721, United States
| | - Jack Godek
- Department of Pharmacology and Toxicology, R. Ken Coit College of Pharmacy, University of Arizona, Tucson, Arizona85721, United States
| | - Vlad K Kumirov
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona85719, United States
| | - Teresa Coma Brujas
- Department of Pharmacology and Toxicology, R. Ken Coit College of Pharmacy, University of Arizona, Tucson, Arizona85721, United States
| | - Joan Torra Garcia
- Department of Pharmacology and Toxicology, R. Ken Coit College of Pharmacy, University of Arizona, Tucson, Arizona85721, United States
| | - Anandhan Annadurai
- Department of Pharmacology and Toxicology, R. Ken Coit College of Pharmacy, University of Arizona, Tucson, Arizona85721, United States
| | - Cody J Schmidlin
- Department of Pharmacology and Toxicology, R. Ken Coit College of Pharmacy, University of Arizona, Tucson, Arizona85721, United States
| | - Alyssa Werner
- Department of Pharmacology and Toxicology, R. Ken Coit College of Pharmacy, University of Arizona, Tucson, Arizona85721, United States
| | - Taoda Shi
- Department of Pharmacology and Toxicology, R. Ken Coit College of Pharmacy, University of Arizona, Tucson, Arizona85721, United States
| | - Reza Beheshti Zavareh
- Department of Chemistry, The Scripps Research Institute, La Jolla, California92037, United States
| | - Luke Lairson
- Department of Chemistry, The Scripps Research Institute, La Jolla, California92037, United States
| | - Donna D Zhang
- Department of Pharmacology and Toxicology, R. Ken Coit College of Pharmacy, University of Arizona, Tucson, Arizona85721, United States
| | - Eli Chapman
- Department of Pharmacology and Toxicology, R. Ken Coit College of Pharmacy, University of Arizona, Tucson, Arizona85721, United States
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6
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Chaperone-Dependent Mechanisms as a Pharmacological Target for Neuroprotection. Int J Mol Sci 2023; 24:ijms24010823. [PMID: 36614266 PMCID: PMC9820882 DOI: 10.3390/ijms24010823] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 12/26/2022] [Accepted: 12/27/2022] [Indexed: 01/05/2023] Open
Abstract
Modern pharmacotherapy of neurodegenerative diseases is predominantly symptomatic and does not allow vicious circles causing disease development to break. Protein misfolding is considered the most important pathogenetic factor of neurodegenerative diseases. Physiological mechanisms related to the function of chaperones, which contribute to the restoration of native conformation of functionally important proteins, evolved evolutionarily. These mechanisms can be considered promising for pharmacological regulation. Therefore, the aim of this review was to analyze the mechanisms of endoplasmic reticulum stress (ER stress) and unfolded protein response (UPR) in the pathogenesis of neurodegenerative diseases. Data on BiP and Sigma1R chaperones in clinical and experimental studies of Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, and Huntington's disease are presented. The possibility of neuroprotective effect dependent on Sigma1R ligand activation in these diseases is also demonstrated. The interaction between Sigma1R and BiP-associated signaling in the neuroprotection is discussed. The performed analysis suggests the feasibility of pharmacological regulation of chaperone function, possibility of ligand activation of Sigma1R in order to achieve a neuroprotective effect, and the need for further studies of the conjugation of cellular mechanisms controlled by Sigma1R and BiP chaperones.
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7
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Pranke IM, Chevalier B, Premchandar A, Baatallah N, Tomaszewski KF, Bitam S, Tondelier D, Golec A, Stolk J, Lukacs GL, Hiemstra PS, Dadlez M, Lomas DA, Irving JA, Delaunay-Moisan A, van Anken E, Hinzpeter A, Sermet-Gaudelus I, Edelman A. Keratin 8 is a scaffolding and regulatory protein of ERAD complexes. Cell Mol Life Sci 2022; 79:503. [PMID: 36045259 DOI: 10.1007/s00018-022-04528-3] [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: 02/07/2022] [Revised: 08/08/2022] [Accepted: 08/12/2022] [Indexed: 11/03/2022]
Abstract
Early recognition and enhanced degradation of misfolded proteins by the endoplasmic reticulum (ER) quality control and ER-associated degradation (ERAD) cause defective protein secretion and membrane targeting, as exemplified for Z-alpha-1-antitrypsin (Z-A1AT), responsible for alpha-1-antitrypsin deficiency (A1ATD) and F508del-CFTR (cystic fibrosis transmembrane conductance regulator) responsible for cystic fibrosis (CF). Prompted by our previous observation that decreasing Keratin 8 (K8) expression increased trafficking of F508del-CFTR to the plasma membrane, we investigated whether K8 impacts trafficking of soluble misfolded Z-A1AT protein. The subsequent goal of this study was to elucidate the mechanism underlying the K8-dependent regulation of protein trafficking, focusing on the ERAD pathway. The results show that diminishing K8 concentration in HeLa cells enhances secretion of both Z-A1AT and wild-type (WT) A1AT with a 13-fold and fourfold increase, respectively. K8 down-regulation triggers ER failure and cellular apoptosis when ER stress is jointly elicited by conditional expression of the µs heavy chains, as previously shown for Hrd1 knock-out. Simultaneous K8 silencing and Hrd1 knock-out did not show any synergistic effect, consistent with K8 acting in the Hrd1-governed ERAD step. Fractionation and co-immunoprecipitation experiments reveal that K8 is recruited to ERAD complexes containing Derlin2, Sel1 and Hrd1 proteins upon expression of Z/WT-A1AT and F508del-CFTR. Treatment of the cells with c407, a small molecule inhibiting K8 interaction, decreases K8 and Derlin2 recruitment to high-order ERAD complexes. This was associated with increased Z-A1AT secretion in both HeLa and Z-homozygous A1ATD patients' respiratory cells. Overall, we provide evidence that K8 acts as an ERAD modulator. It may play a scaffolding protein role for early-stage ERAD complexes, regulating Hrd1-governed retrotranslocation initiation/ubiquitination processes. Targeting K8-containing ERAD complexes is an attractive strategy for the pharmacotherapy of A1ATD.
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Affiliation(s)
- Iwona Maria Pranke
- Inserm, U1151, CNRS UMR 8253, Université de Paris, 160 rue de Vaugirard, 75015, Paris, France.
| | - Benoit Chevalier
- Inserm, U1151, CNRS UMR 8253, Université de Paris, 160 rue de Vaugirard, 75015, Paris, France
| | - Aiswarya Premchandar
- Laboratory of Mass Spectrometry, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02106, Warsaw, Poland
| | - Nesrine Baatallah
- Inserm, U1151, CNRS UMR 8253, Université de Paris, 160 rue de Vaugirard, 75015, Paris, France
| | - Kamil F Tomaszewski
- Inserm, U1151, CNRS UMR 8253, Université de Paris, 160 rue de Vaugirard, 75015, Paris, France
| | - Sara Bitam
- Inserm, U1151, CNRS UMR 8253, Université de Paris, 160 rue de Vaugirard, 75015, Paris, France
| | - Danielle Tondelier
- Inserm, U1151, CNRS UMR 8253, Université de Paris, 160 rue de Vaugirard, 75015, Paris, France
| | - Anita Golec
- Inserm, U1151, CNRS UMR 8253, Université de Paris, 160 rue de Vaugirard, 75015, Paris, France
| | - Jan Stolk
- Department of Pulmonology, Leiden University Medical Center, Leiden, The Netherlands
| | - Gergely L Lukacs
- Department of Physiology, McGill University, Montréal, QC, Canada.,Department of Biochemistry, McGill University, Montréal, QC, Canada
| | - Pieter S Hiemstra
- Department of Pulmonology, Leiden University Medical Center, Leiden, The Netherlands
| | - Michal Dadlez
- Laboratory of Mass Spectrometry, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02106, Warsaw, Poland
| | - David A Lomas
- UCL Respiratory and the Institute of Structural and Molecular Biology, University College London, London, WC1E 6JF, UK
| | - James A Irving
- UCL Respiratory and the Institute of Structural and Molecular Biology, University College London, London, WC1E 6JF, UK
| | - Agnes Delaunay-Moisan
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Gif-sur-Yvette, France
| | - Eelco van Anken
- Division of Genetics and Cell Biology, San Raffaele Scientific Institute, Milan, Italy
| | - Alexandre Hinzpeter
- Inserm, U1151, CNRS UMR 8253, Université de Paris, 160 rue de Vaugirard, 75015, Paris, France
| | - Isabelle Sermet-Gaudelus
- Inserm, U1151, CNRS UMR 8253, Université de Paris, 160 rue de Vaugirard, 75015, Paris, France.,Cystic Fibrosis Center, Hôpital Necker Enfants Malades, Assistance Publique Hôpitaux de Paris, Paris, France
| | - Aleksander Edelman
- Inserm, U1151, CNRS UMR 8253, Université de Paris, 160 rue de Vaugirard, 75015, Paris, France.
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8
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Gómez-Puerta S, Ferrero R, Hochstoeger T, Zubiri I, Chao J, Aragón T, Voigt F. Live imaging of the co-translational recruitment of XBP1 mRNA to the ER and its processing by diffuse, non-polarized IRE1α. eLife 2022; 11:e75580. [PMID: 35730412 PMCID: PMC9217131 DOI: 10.7554/elife.75580] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 06/01/2022] [Indexed: 11/13/2022] Open
Abstract
Endoplasmic reticulum (ER) to nucleus homeostatic signaling, known as the unfolded protein response (UPR), relies on the non-canonical splicing of XBP1 mRNA. The molecular switch that initiates splicing is the oligomerization of the ER stress sensor and UPR endonuclease IRE1α (inositol-requiring enzyme 1 alpha). While IRE1α can form large clusters that have been proposed to function as XBP1 processing centers on the ER, the actual oligomeric state of active IRE1α complexes as well as the targeting mechanism that recruits XBP1 to IRE1α oligomers remains unknown. Here, we have developed a single-molecule imaging approach to monitor the recruitment of individual XBP1 transcripts to the ER surface. Using this methodology, we confirmed that stable ER association of unspliced XBP1 mRNA is established through HR2 (hydrophobic region 2)-dependent targeting and relies on active translation. In addition, we show that IRE1α-catalyzed splicing mobilizes XBP1 mRNA from the ER membrane in response to ER stress. Surprisingly, we find that XBP1 transcripts are not recruited into large IRE1α clusters, which are only observed upon overexpression of fluorescently tagged IRE1α during ER stress. Our findings support a model where ribosome-engaged, immobilized XBP1 mRNA is processed by small IRE1α assemblies that could be dynamically recruited for processing of mRNA transcripts on the ER.
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Affiliation(s)
- Silvia Gómez-Puerta
- Department of Gene Therapy and Regulation of Gene Expression, Center for Applied Medical Research (CIMA), University of NavarraPamplonaSpain
| | - Roberto Ferrero
- Department of Gene Therapy and Regulation of Gene Expression, Center for Applied Medical Research (CIMA), University of NavarraPamplonaSpain
| | - Tobias Hochstoeger
- Friedrich Miescher Institute for Biomedical ResearchBaselSwitzerland
- University of BaselBaselSwitzerland
| | - Ivan Zubiri
- Department of Gene Therapy and Regulation of Gene Expression, Center for Applied Medical Research (CIMA), University of NavarraPamplonaSpain
| | - Jeffrey Chao
- Friedrich Miescher Institute for Biomedical ResearchBaselSwitzerland
| | - Tomás Aragón
- Department of Gene Therapy and Regulation of Gene Expression, Center for Applied Medical Research (CIMA), University of NavarraPamplonaSpain
| | - Franka Voigt
- Friedrich Miescher Institute for Biomedical ResearchBaselSwitzerland
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9
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Dyskerin Downregulation Can Induce ER Stress and Promote Autophagy via AKT-mTOR Signaling Deregulation. Biomedicines 2022; 10:biomedicines10051092. [PMID: 35625829 PMCID: PMC9138296 DOI: 10.3390/biomedicines10051092] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 04/28/2022] [Accepted: 05/04/2022] [Indexed: 02/05/2023] Open
Abstract
Dyskerin is an evolutionarily conserved nucleolar protein implicated in a wide range of fundamental biological roles, including telomere maintenance and ribosome biogenesis. Germline mutations of DKC1, the human gene encoding dyskerin, cause the hereditary disorders known as X-linked dyskeratosis congenita (X-DC). Moreover, dyskerin is upregulated in several cancers. Due to the pleiotropic functions of dyskerin, the X-DC clinical features overlap with those of both telomeropathies and ribosomopathies. In this paper, we evaluate the telomerase-independent effects of dyskerin depletion on cellular physiology by using inducible DCK1 knockdown. This system allows the downregulation of DKC1 expression within a short timeframe. We report that, in these cellular systems, dyskerin depletion induces the accumulation of unfolded/misfolded proteins in the endoplasmic reticulum, which in turn induces the activation of the PERK branch of the unfolded protein response. We also demonstrate that the PERK-eIF2a-ATF4-CHOP signaling pathway, activated by dyskerin downregulation, triggers a functional autophagic flux through the inhibition of the PI3K/AKT/mTOR pathway. By revealing a novel unpredicted connection between the loss of dyskerin, autophagy and UPR, our results establish a firm link between the lowering of dyskerin levels and the activation of the ER stress response, that plays a key role in the pathogenesis of several diseases.
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10
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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: 11] [Impact Index Per Article: 5.5] [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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11
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Muronetz VI, Kudryavtseva SS, Leisi EV, Kurochkina LP, Barinova KV, Schmalhausen EV. Regulation by Different Types of Chaperones of Amyloid Transformation of Proteins Involved in the Development of Neurodegenerative Diseases. Int J Mol Sci 2022; 23:ijms23052747. [PMID: 35269889 PMCID: PMC8910861 DOI: 10.3390/ijms23052747] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 02/21/2022] [Accepted: 02/28/2022] [Indexed: 02/06/2023] Open
Abstract
The review highlights various aspects of the influence of chaperones on amyloid proteins associated with the development of neurodegenerative diseases and includes studies conducted in our laboratory. Different sections of the article are devoted to the role of chaperones in the pathological transformation of alpha-synuclein and the prion protein. Information about the interaction of the chaperonins GroE and TRiC as well as polymer-based artificial chaperones with amyloidogenic proteins is summarized. Particular attention is paid to the effect of blocking chaperones by misfolded and amyloidogenic proteins. It was noted that the accumulation of functionally inactive chaperones blocked by misfolded proteins might cause the formation of amyloid aggregates and prevent the disassembly of fibrillar structures. Moreover, the blocking of chaperones by various forms of amyloid proteins might lead to pathological changes in the vital activity of cells due to the impaired folding of newly synthesized proteins and their subsequent processing. The final section of the article discusses both the little data on the role of gut microbiota in the propagation of synucleinopathies and prion diseases and the possible involvement of the bacterial chaperone GroE in these processes.
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Affiliation(s)
- Vladimir I. Muronetz
- Belozersky Institute of Physico Chemical Biology, Lomonosov Moscow State University, 119991 Moscow, Russia; (L.P.K.); (K.V.B.); (E.V.S.)
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, 119991 Moscow, Russia;
- Correspondence:
| | - Sofia S. Kudryavtseva
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, 119991 Moscow, Russia;
- Faculty of Biology, Lomonosov Moscow State University, 119991 Moscow, Russia;
| | - Evgeniia V. Leisi
- Faculty of Biology, Lomonosov Moscow State University, 119991 Moscow, Russia;
| | - Lidia P. Kurochkina
- Belozersky Institute of Physico Chemical Biology, Lomonosov Moscow State University, 119991 Moscow, Russia; (L.P.K.); (K.V.B.); (E.V.S.)
| | - Kseniya V. Barinova
- Belozersky Institute of Physico Chemical Biology, Lomonosov Moscow State University, 119991 Moscow, Russia; (L.P.K.); (K.V.B.); (E.V.S.)
| | - Elena V. Schmalhausen
- Belozersky Institute of Physico Chemical Biology, Lomonosov Moscow State University, 119991 Moscow, Russia; (L.P.K.); (K.V.B.); (E.V.S.)
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12
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Kyeong M, Lee JS. Endogenous BiP reporter system for simultaneous identification of ER stress and antibody production in Chinese hamster ovary cells. Metab Eng 2022; 72:35-45. [PMID: 35182754 DOI: 10.1016/j.ymben.2022.02.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 01/11/2022] [Accepted: 02/07/2022] [Indexed: 12/28/2022]
Abstract
As the biopharmaceutical industry expands, improving the production of therapeutic proteins using Chinese hamster ovary (CHO) cells is important. However, excessive and complicated protein production causes protein misfolding and triggers endoplasmic reticulum (ER) stress. When ER stress occurs, cells mediate the unfolded protein response (UPR) pathway to restore protein homeostasis and folding capacity of the ER. However, when the cells fail to control prolonged ER stress, UPR induces apoptosis. Therefore, monitoring the degree of UPR is required to achieve high productivity and the desired quality. In this study, we developed a fluorescence-based UPR monitoring system for CHO cells. We integrated mGFP into endogenous HSPA5 encoding BiP, a major ER chaperone, and the primary ER stress activation sensor, using CRISPR/Cas9-mediated targeted integration. The mGFP expression level changed according to the ER stress induced by chemical treatment and batch culture in the engineered cell line. Using this monitoring system, we demonstrated that host cells and recombinant CHO cell lines with different mean fluorescence intensities (MFI; basal expression levels of BiP) possess a distinct capacity for stress culture conditions induced by recombinant protein production. Antibody-producing recombinant CHO cell lines were generated using site-specific integration based on host cells equipped with the BiP reporter system. Targeted integrants showed a strong correlation between productivity and MFI, reflecting the potential of this monitoring system as a screening readout for high producers. Taken together, these data demonstrate the utility of the endogenous BiP reporter system for the detection of real-time dynamic changes in endogenous UPR and its potential for applications in recombinant protein production during CHO cell line development.
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Affiliation(s)
- Minji Kyeong
- Department of Molecular Science and Technology, Ajou University, Suwon, 16499, Republic of Korea
| | - Jae Seong Lee
- Department of Molecular Science and Technology, Ajou University, Suwon, 16499, Republic of Korea.
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13
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Wang J, Chen M, Wang M, Zhao W, Zhang C, Liu X, Cai M, Qiu Y, Zhang T, Zhou H, Zhao W, Si S, Shao R. The novel ER stress inducer Sec C triggers apoptosis by sulfating ER cysteine residues and degrading YAP via ER stress in pancreatic cancer cells. Acta Pharm Sin B 2022; 12:210-227. [PMID: 35127381 PMCID: PMC8800039 DOI: 10.1016/j.apsb.2021.07.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 06/11/2021] [Accepted: 06/16/2021] [Indexed: 12/14/2022] Open
Abstract
Pancreatic adenocarcinoma (PAAD) is one of the most lethal malignancies. Although gemcitabine (GEM) is a standard treatment for PAAD, resistance limits its application and therapy. Secoemestrin C (Sec C) is a natural compound from the endophytic fungus Emericella, and its anticancer activity has not been investigated since it was isolated. Our research is the first to indicate that Sec C is a broad-spectrum anticancer agent and could exhibit potently similar anticancer activity both in GEM-resistant and GEM-sensitive PAAD cells. Interestingly, Sec C exerted a rapid growth-inhibiting effect (80% death at 6 h), which might be beneficial for patients who need rapid tumor shrinkage before surgery. Liquid chromatography/mass spectrometry and N-acetyl-l-cysteine (NAC) reverse assays show that Sec C sulfates cysteines to disrupt disulfide-bonds formation in endoplasmic reticulum (ER) proteins to cause protein misfolding, leading to ER stress and disorder of lipid biosynthesis. Microarray data and subsequent assays show that ER stress-mediated ER-associated degradation (ERAD) ubiquitinates and downregulates YAP to enhance ER stress via destruction complex (YAP-Axin-GSK-βTrCP), which also elucidates a unique degrading style for YAP. Potent anticancer activity in GEM-resistant cells and low toxicity make Sec C a promising anti-PAAD candidate.
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Affiliation(s)
| | | | - Mengyan Wang
- Key Laboratory of Antibiotic Bioengineering, Ministry of Health, Laboratory of Oncology, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Wenxia Zhao
- Key Laboratory of Antibiotic Bioengineering, Ministry of Health, Laboratory of Oncology, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Conghui Zhang
- Key Laboratory of Antibiotic Bioengineering, Ministry of Health, Laboratory of Oncology, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Xiujun Liu
- Key Laboratory of Antibiotic Bioengineering, Ministry of Health, Laboratory of Oncology, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Meilian Cai
- Key Laboratory of Antibiotic Bioengineering, Ministry of Health, Laboratory of Oncology, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Yuhan Qiu
- Key Laboratory of Antibiotic Bioengineering, Ministry of Health, Laboratory of Oncology, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Tianshu Zhang
- Key Laboratory of Antibiotic Bioengineering, Ministry of Health, Laboratory of Oncology, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Huimin Zhou
- Key Laboratory of Antibiotic Bioengineering, Ministry of Health, Laboratory of Oncology, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Wuli Zhao
- Key Laboratory of Antibiotic Bioengineering, Ministry of Health, Laboratory of Oncology, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Shuyi Si
- Key Laboratory of Antibiotic Bioengineering, Ministry of Health, Laboratory of Oncology, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Rongguang Shao
- Key Laboratory of Antibiotic Bioengineering, Ministry of Health, Laboratory of Oncology, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
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14
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Lee HM, Lee SC, He L, Kong APS, Mao D, Hou Y, Chung ACK, Xu G, Ma RCW, Chan JCN. Legacy effect of high glucose on promoting survival of HCT116 colorectal cancer cells by reducing endoplasmic reticulum stress response. Am J Cancer Res 2021; 11:6004-6023. [PMID: 35018239 PMCID: PMC8727802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2021] [Accepted: 10/25/2021] [Indexed: 06/14/2023] Open
Abstract
Patients with diabetes have increased risk of cancer and poor response to anti-cancer treatment. Increased protein synthesis is associated with endoplasmic reticulum (ER) stress which can trigger the unfolded protein response (UPR) to restore homeostasis, failure of which can lead to dysregulated cellular growth. We hypothesize that hyperglycemia may have legacy effect in promoting survival of cancer cells through dysregulation of UPR. Using HCT116 colorectal cancer cells as a model, we demonstrated the effects of high glucose (25 mM) on promoting cell growth which persisted despite return to normal glucose medium (5.6 mM). Using the Affymetrix gene expression microarray in HCT116 cells programmed by high glucose, we observed activation of genes related to cell proliferation and cell cycle progression and suppression of genes implicated in UPR including BiP and CHOP. These gene expression changes were validated in HCT116 cancer cells using quantitative real-time PCR and Western blot analysis. We further examined the effects of thapsigargin, an anti-cancer prodrug, which utilized ER stress pathway to induce apoptosis. High glucose attenuated thapsigargin-induced UPR and growth inhibition in HCT116 cells, which persisted despite return to normal glucose medium. Western blot analysis showed activation of caspase-3 in thapsigargin-treated cells in both normal and high glucose medium, albeit with lower levels of cleaved caspase-3 in cells exposed to high glucose, suggesting reduced apoptosis. Flow cytometry analysis confirmed fewer apoptotic cells under thapsigargin treatment in cells exposed to high glucose. Our results suggested that hyperglycemia altered gene expression involved in UPR with increased cell proliferation and facilitated survival of HCT116 cells under thapsigargin-induced ER stress by reducing the apoptotic response.
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Affiliation(s)
- Heung Man Lee
- Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Prince of Wales HospitalShatin, Hong Kong
- Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Prince of Wales HospitalShatin, Hong Kong
| | - Shao Chin Lee
- Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Prince of Wales HospitalShatin, Hong Kong
- Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Prince of Wales HospitalShatin, Hong Kong
- Department of Biological Sciences, School of Life Sciences, Shanxi UniversityTaiyuan 030006, Shanxi, China
| | - Lan He
- Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Prince of Wales HospitalShatin, Hong Kong
- Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Prince of Wales HospitalShatin, Hong Kong
| | - Alice Pik Shan Kong
- Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Prince of Wales HospitalShatin, Hong Kong
- Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Prince of Wales HospitalShatin, Hong Kong
- Hong Kong Institute of Diabetes and Obesity, The Chinese University of Hong Kong, Prince of Wales HospitalShatin, Hong Kong
| | - Dandan Mao
- Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Prince of Wales HospitalShatin, Hong Kong
- Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Prince of Wales HospitalShatin, Hong Kong
| | - Yong Hou
- Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Prince of Wales HospitalShatin, Hong Kong
- Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Prince of Wales HospitalShatin, Hong Kong
| | | | - Gang Xu
- Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Prince of Wales HospitalShatin, Hong Kong
- Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Prince of Wales HospitalShatin, Hong Kong
- Hong Kong Institute of Diabetes and Obesity, The Chinese University of Hong Kong, Prince of Wales HospitalShatin, Hong Kong
| | - Ronald Ching Wan Ma
- Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Prince of Wales HospitalShatin, Hong Kong
- Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Prince of Wales HospitalShatin, Hong Kong
- Hong Kong Institute of Diabetes and Obesity, The Chinese University of Hong Kong, Prince of Wales HospitalShatin, Hong Kong
| | - Juliana Chung Ngor Chan
- Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Prince of Wales HospitalShatin, Hong Kong
- Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Prince of Wales HospitalShatin, Hong Kong
- Hong Kong Institute of Diabetes and Obesity, The Chinese University of Hong Kong, Prince of Wales HospitalShatin, Hong Kong
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15
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Trouvé P, Férec C, Génin E. The Interplay between the Unfolded Protein Response, Inflammation and Infection in Cystic Fibrosis. Cells 2021; 10:2980. [PMID: 34831204 PMCID: PMC8616505 DOI: 10.3390/cells10112980] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 10/25/2021] [Accepted: 10/29/2021] [Indexed: 12/15/2022] Open
Abstract
In cystic fibrosis (CF), p.Phe508del is the most frequent mutation in the Cystic Fibrosis Transmembrane conductance Regulator (CFTR) gene. The p.Phe508del-CFTR protein is retained in the ER and rapidly degraded. This retention likely triggers an atypical Unfolded Protein Response (UPR) involving ATF6, which reduces the expression of p.Phe508del-CFTR. There are still some debates on the role of the UPR in CF: could it be triggered by the accumulation of misfolded CFTR proteins in the endoplasmic reticulum as was proposed for the most common CFTR mutation p.Phe508del? Or, is it the consequence of inflammation and infection that occur in the disease? In this review, we summarize recent findings on UPR in CF and show how infection, inflammation and UPR act together in CF. We propose to rethink their respective role in CF and to consider them as a whole.
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Affiliation(s)
- Pascal Trouvé
- Inserm, Univ Brest, EFS, UMR 1078, GGB, F-29200 Brest, France; (C.F.); (E.G.)
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16
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Shen L, Gao J, Wang Y, Li X, Liu H, Zhong Y. Engineering the endoplasmic reticulum secretory pathway in Trichoderma reesei for improved cellulase production. Enzyme Microb Technol 2021; 152:109923. [PMID: 34688089 DOI: 10.1016/j.enzmictec.2021.109923] [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: 08/03/2021] [Revised: 09/18/2021] [Accepted: 09/29/2021] [Indexed: 10/20/2022]
Abstract
The filamentous fungus Trichoderma reesei is an extraordinarily efficient cell factory of industrial cellulase for production of biofuels and other bio-based products because of its excellent potential to secrete cellulolytic enzymes. Engineering the protein secretory pathway may be a powerful means for efficient protein production. However, it is uncertain whether this engineering approach could improve cellulase production in T. reesei. Herein, the endoplasmic reticulum (ER) secretory pathway was engineered for the production of cellulolytic enzymes by multiple strategies, including: (I) overexpression of the key components of protein folding (Pdi1, Ero1 and BiP); (II) overexpression of the glycosylation-related elements (Gpt1 and Gls2); (III) knockout of the ER mannosidase I (Mns1) encoding gene mns1. By utilizing these ER engineering strategies, the secretion of β-glucosidase was remarkably elevated in the engineered strains, ranging from 29.2 % to 112.5 %. Furthermore, it was found that engineering these components also regulated the ER stress resistance. More importantly, the total cellulase production was increased with varying degrees, which reached a maximum of 149.4 %, using the filter paper assay (FPA) as a characterization method. These results demonstrated that engineering the ER secretory pathway can enhance protein secretion, particularly for cellulase production, which shed light for the development of high-efficient cellulolytic enzymes for economically feasible bioethanol production from lignocellulosic biomass.
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Affiliation(s)
- Linjing Shen
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao 266237, PR China
| | - Jia Gao
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao 266237, PR China
| | - Yifan Wang
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao 266237, PR China
| | - Xihai Li
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao 266237, PR China
| | - Hong Liu
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao 266237, PR China.
| | - Yaohua Zhong
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao 266237, PR China
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17
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Anelli T, Dalla Torre M, Borini E, Mangini E, Ulisse A, Semino C, Sitia R, Panina-Bordignon P. Profound architectural and functional readjustments of the secretory pathway in decidualization of endometrial stromal cells. Traffic 2021; 23:4-20. [PMID: 34651407 DOI: 10.1111/tra.12822] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 07/10/2021] [Accepted: 10/07/2021] [Indexed: 12/19/2022]
Abstract
Certain cell types must expand their exocytic pathway to guarantee efficiency and fidelity of protein secretion. A spectacular case is offered by decidualizing human endometrial stromal cells (EnSCs). In the midluteal phase of the menstrual cycle, progesterone stimulation induces proliferating EnSCs to differentiate into professional secretors releasing proteins essential for efficient blastocyst implantation. Here, we describe the architectural rearrangements of the secretory pathway of a human EnSC line (TERT-immortalized human endometrial stromal cells (T-HESC)). As in primary cells, decidualization entails proliferation arrest and the coordinated expansion of the entire secretory pathway without detectable activation of unfolded protein response (UPR) pathways. Decidualization proceeds also in the absence of ascorbic acid, an essential cofactor for collagen biogenesis, despite also the secretion of some proteins whose folding does not depend on vitamin C is impaired. However, even in these conditions, no overt UPR induction can be detected. Morphometric analyses reveal that the exocytic pathway does not increase relatively to the volume of the cell. Thus, differently from other cell types, abundant production is guaranteed by a coordinated increase of the cell size following arrest of proliferation.
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Affiliation(s)
- Tiziana Anelli
- Faculty of Medicine, San Raffaele Vita-Salute University, Milan, Italy.,Division of Genetics and Cell Biology, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Marco Dalla Torre
- Faculty of Medicine, San Raffaele Vita-Salute University, Milan, Italy
| | - Elena Borini
- Faculty of Medicine, San Raffaele Vita-Salute University, Milan, Italy
| | - Elisabetta Mangini
- Division of Genetics and Cell Biology, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Adele Ulisse
- Division of Genetics and Cell Biology, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Claudia Semino
- Division of Genetics and Cell Biology, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Roberto Sitia
- Faculty of Medicine, San Raffaele Vita-Salute University, Milan, Italy.,Division of Genetics and Cell Biology, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Paola Panina-Bordignon
- Faculty of Medicine, San Raffaele Vita-Salute University, Milan, Italy.,Division of Neuroscience, IRCCS Ospedale San Raffaele, Milan, Italy
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18
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Endosomal trafficking and DNA damage checkpoint kinases dictate survival to replication stress by regulating amino acid uptake and protein synthesis. Dev Cell 2021; 56:2607-2622.e6. [PMID: 34534458 DOI: 10.1016/j.devcel.2021.08.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 06/11/2021] [Accepted: 08/20/2021] [Indexed: 12/22/2022]
Abstract
Atg6Beclin 1 mediates autophagy and endosomal trafficking. We investigated how Atg6 influences replication stress. Combining genetic, genomic, metabolomic, and proteomic approaches, we found that the Vps34-Vps15-Atg6Beclin 1-Vps38UVRAG-phosphatydilinositol-3 phosphate (PtdIns(3)P) axis sensitizes cells to replication stress by favoring the degradation of plasma membrane amino acid (AA) transporters via endosomal trafficking and ESCRT proteins, while the PtdIns(3)P phosphatases Ymr1 and Inp53 promote survival to replication stress by reversing this process. An impaired AA uptake triggers activation of Gcn2, which attenuates protein synthesis by phosphorylating eIF2α. Mec1Atr-Rad53Chk1/Chk2 activation during replication stress further hinders translation efficiency by counteracting eIF2α dephosphorylation through Glc7PP1. AA shortage-induced hyperphosphorylation of eIF2α inhibits the synthesis of 65 stress response proteins, thus resulting in cell sensitization to replication stress, while TORC1 promotes cell survival. Our findings reveal an integrated network mediated by endosomal trafficking, translational control pathways, and checkpoint kinases linking AA availability to the response to replication stress.
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19
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Pick T, Beck A, Gamayun I, Schwarz Y, Schirra C, Jung M, Krause E, Niemeyer BA, Zimmermann R, Lang S, Anken EV, Cavalié A. Remodelling of Ca 2+ homeostasis is linked to enlarged endoplasmic reticulum in secretory cells. Cell Calcium 2021; 99:102473. [PMID: 34560367 DOI: 10.1016/j.ceca.2021.102473] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 08/27/2021] [Accepted: 09/08/2021] [Indexed: 11/30/2022]
Abstract
The endoplasmic reticulum (ER) is extensively remodelled during the development of professional secretory cells to cope with high protein production. Since ER is the principal Ca2+ store in the cell, we characterised the Ca2+ homeostasis in NALM-6 and RPMI 8226 cells, which are commonly used as human pre-B and antibody secreting plasma cell models, respectively. Expression levels of Sec61 translocons and the corresponding Sec61-mediated Ca2+ leak from ER, Ca2+ storage capacity and store-operated Ca2+ entry were significantly enlarged in the secretory RPMI 8226 cell line. Using an immunoglobulin M heavy chain producing HeLa cell model, we found that the enlarged Ca2+ storage capacity and Ca2+ leak from ER are linked to ER expansion. Our data delineates a developmental remodelling of Ca2+ homeostasis in professional secretory cells in which a high Sec61-mediated Ca2+ leak and, thus, a high Ca2+ turnover in the ER is backed up by enhanced store-operated Ca2+ entry.
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Affiliation(s)
- Tillman Pick
- Experimental and Clinical Pharmacology and Toxicology, Pre-clinical Center for Molecular Signalling (PZMS), Saarland University, 66421 Homburg, Germany.
| | - Andreas Beck
- Experimental and Clinical Pharmacology and Toxicology, Pre-clinical Center for Molecular Signalling (PZMS), Saarland University, 66421 Homburg, Germany
| | - Igor Gamayun
- Experimental and Clinical Pharmacology and Toxicology, Pre-clinical Center for Molecular Signalling (PZMS), Saarland University, 66421 Homburg, Germany
| | - Yvonne Schwarz
- Molecular Neurophysiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, 66421 Homburg, Germany
| | - Claudia Schirra
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, 66421 Homburg, Germany
| | - Martin Jung
- Medical Biochemistry and Molecular Biology, Pre-clinical Centre for Molecular Signalling (PZMS), Saarland University, 66421 Homburg, Germany
| | - Elmar Krause
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, 66421 Homburg, Germany
| | - Barbara A Niemeyer
- Molecular Biophysics, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, 66421 Homburg, Germany
| | - Richard Zimmermann
- Medical Biochemistry and Molecular Biology, Pre-clinical Centre for Molecular Signalling (PZMS), Saarland University, 66421 Homburg, Germany
| | - Sven Lang
- Medical Biochemistry and Molecular Biology, Pre-clinical Centre for Molecular Signalling (PZMS), Saarland University, 66421 Homburg, Germany
| | - Eelco van Anken
- Division of Genetics and Cell Biology, San Raffaele Scientific Institute and Università Vita-Salute San Raffaele, Milan, Italy
| | - Adolfo Cavalié
- Experimental and Clinical Pharmacology and Toxicology, Pre-clinical Center for Molecular Signalling (PZMS), Saarland University, 66421 Homburg, Germany.
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20
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Verma K, Verma M, Chaphalkar A, Chakraborty K. Recent advances in understanding the role of proteostasis. Fac Rev 2021; 10:72. [PMID: 34632458 PMCID: PMC8483240 DOI: 10.12703/r/10-72] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Maintenance of a functional proteome is achieved through the mechanism of proteostasis that involves precise coordination between molecular machineries assisting a protein from its conception to demise. Although each organelle within a cell has its own set of proteostasis machinery, inter-organellar communication and cell non-autonomous signaling bring forth the multidimensional nature of the proteostasis network. Exposure to extrinsic and intrinsic stressors can challenge the proteostasis network, leading to the accumulation of aberrant proteins or a decline in the proteostasis components, as seen during aging and in several diseases. Here, we summarize recent advances in understanding the role of proteostasis and its regulation in aging and disease, including monogenetic and infectious diseases. We highlight some of the emerging as well as unresolved questions in proteostasis that need to be addressed to overcome pathologies associated with damaged proteins and to promote healthy aging.
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Affiliation(s)
- Kanika Verma
- CSIR-Institute of Genomics and Integrative Biology, Mathura Road, Delhi, India
- Academy of Scientific and Innovative Research, CSIR-HRDC, Ghaziabad, Uttar Pradesh, India
| | - Monika Verma
- CSIR-Institute of Genomics and Integrative Biology, Mathura Road, Delhi, India
- Academy of Scientific and Innovative Research, CSIR-HRDC, Ghaziabad, Uttar Pradesh, India
| | - Aseem Chaphalkar
- CSIR-Institute of Genomics and Integrative Biology, Mathura Road, Delhi, India
- Academy of Scientific and Innovative Research, CSIR-HRDC, Ghaziabad, Uttar Pradesh, India
| | - Kausik Chakraborty
- CSIR-Institute of Genomics and Integrative Biology, Mathura Road, Delhi, India
- Academy of Scientific and Innovative Research, CSIR-HRDC, Ghaziabad, Uttar Pradesh, India
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21
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Mazel-Sanchez B, Iwaszkiewicz J, Bonifacio JPP, Silva F, Niu C, Strohmeier S, Eletto D, Krammer F, Tan G, Zoete V, Hale BG, Schmolke M. Influenza A viruses balance ER stress with host protein synthesis shutoff. Proc Natl Acad Sci U S A 2021; 118:e2024681118. [PMID: 34479996 PMCID: PMC8433552 DOI: 10.1073/pnas.2024681118] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 07/15/2021] [Indexed: 02/06/2023] Open
Abstract
Excessive production of viral glycoproteins during infections poses a tremendous stress potential on the endoplasmic reticulum (ER) protein folding machinery of the host cell. The host cell balances this by providing more ER resident chaperones and reducing translation. For viruses, this unfolded protein response (UPR) offers the potential to fold more glycoproteins. We postulated that viruses could have developed means to limit the inevitable ER stress to a beneficial level for viral replication. Using a relevant human pathogen, influenza A virus (IAV), we first established the determinant for ER stress and UPR induction during infection. In contrast to a panel of previous reports, we identified neuraminidase to be the determinant for ER stress induction, and not hemagglutinin. IAV relieves ER stress by expression of its nonstructural protein 1 (NS1). NS1 interferes with the host messenger RNA processing factor CPSF30 and suppresses ER stress response factors, such as XBP1. In vivo viral replication is increased when NS1 antagonizes ER stress induction. Our results reveal how IAV optimizes glycoprotein expression by balancing folding capacity.
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Affiliation(s)
- Beryl Mazel-Sanchez
- Department of Microbiology and Molecular Medicine, University of Geneva, 1211 Geneva, Switzerland
| | - Justyna Iwaszkiewicz
- Molecular Modelling Group, Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland
| | - Joao P P Bonifacio
- Department of Microbiology and Molecular Medicine, University of Geneva, 1211 Geneva, Switzerland
| | - Filo Silva
- Department of Microbiology and Molecular Medicine, University of Geneva, 1211 Geneva, Switzerland
| | - Chengyue Niu
- Department of Microbiology and Molecular Medicine, University of Geneva, 1211 Geneva, Switzerland
| | - Shirin Strohmeier
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029
| | - Davide Eletto
- Institute of Medical Virology, University of Zürich, 8057 Zürich, Switzerland
| | - Florian Krammer
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029
| | - Gene Tan
- Infectious Diseases, J. Craig Venter Institute, La Jolla, CA 92037
- Division of Infectious Diseases, Department of Medicine, School of Medicine, University of California San Diego, La Jolla, CA 92093
| | - Vincent Zoete
- Molecular Modelling Group, Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland
| | - Benjamin G Hale
- Institute of Medical Virology, University of Zürich, 8057 Zürich, Switzerland
| | - Mirco Schmolke
- Department of Microbiology and Molecular Medicine, University of Geneva, 1211 Geneva, Switzerland;
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22
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Structures of a deAMPylation complex rationalise the switch between antagonistic catalytic activities of FICD. Nat Commun 2021; 12:5004. [PMID: 34408154 PMCID: PMC8373988 DOI: 10.1038/s41467-021-25076-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 07/15/2021] [Indexed: 12/22/2022] Open
Abstract
The endoplasmic reticulum (ER) Hsp70 chaperone BiP is regulated by AMPylation, a reversible inactivating post-translational modification. Both BiP AMPylation and deAMPylation are catalysed by a single ER-localised enzyme, FICD. Here we present crystallographic and solution structures of a deAMPylation Michaelis complex formed between mammalian AMPylated BiP and FICD. The latter, via its tetratricopeptide repeat domain, binds a surface that is specific to ATP-state Hsp70 chaperones, explaining the exquisite selectivity of FICD for BiP’s ATP-bound conformation both when AMPylating and deAMPylating Thr518. The eukaryotic deAMPylation mechanism thus revealed, rationalises the role of the conserved Fic domain Glu234 as a gatekeeper residue that both inhibits AMPylation and facilitates hydrolytic deAMPylation catalysed by dimeric FICD. These findings point to a monomerisation-induced increase in Glu234 flexibility as the basis of an oligomeric state-dependent switch between FICD’s antagonistic activities, despite a similar mode of engagement of its two substrates — unmodified and AMPylated BiP. The ER chaperone BiP is regulated by FICD-mediated AMPylation and deAMPylation. Here, the authors characterise the structure of mammalian AMPylated BiP bound to FICD, by X-ray crystallography and neutron scattering, providing insights into the mechanism of BiP AMPylation and deAMPylation.
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23
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Huang R, Hui Z, Wei S, Li D, Li W, Daping W, Alahdal M. IRE1 signaling regulates chondrocyte apoptosis and death fate in the osteoarthritis. J Cell Physiol 2021; 237:118-127. [PMID: 34297411 PMCID: PMC9291116 DOI: 10.1002/jcp.30537] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 07/08/2021] [Accepted: 07/10/2021] [Indexed: 12/19/2022]
Abstract
IRE1 is an important central regulator of unfolded protein response (UPR) in the endoplasmic reticulum (ER) because of its ability to regulate cell fate as a function of stress sensing. When misfolded proteins accumulated in chondrocytes ER, IRE1 disintegrates with BIP/GRP78 and undergoes dimer/oligomerization and transautophosphorylation. These two processes are mediated through an enzyme activity of IRE1 to activate endoribonuclease and generates XBP1 by unconventional splicing of XBP1 messenger RNA. Thereby promoting the transcription of UPR target genes and apoptosis. The deficiency of inositol-requiring enzyme 1α (IRE1α) in chondrocytes downregulates prosurvival factors XBP1S and Bcl-2, which enhances the apoptosis of chondrocytes through increasing proapoptotic factors caspase-3, p-JNK, and CHOP. Meanwhile, the activation of IRE1α increases chondrocyte viability and reduces cell apoptosis. However, the understanding of IRE1 responses and cell death fate remains controversial. This review provides updated data about the role IRE1 plays in chondrocytes and new insights about the potential efficacy of IRE1 regulation in cartilage repair and osteoarthritis treatment.
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Affiliation(s)
- Rongxiang Huang
- Shenzhen Key Laboratory of Tissue Engineering, Shenzhen Laboratory of Digital Orthopedic Engineering, Guangdong Provincial Research Center for Artificial Intelligence and Digital Orthopedic Technology, Shenzhen Second People's Hospital (The First Hospital Affiliated to Shenzhen University, Health Science Center), Shenzhen, China.,Clinical Medicine Department, School of Medicine, University of South China, Hengyang, China
| | - Zhang Hui
- Shenzhen Key Laboratory of Tissue Engineering, Shenzhen Laboratory of Digital Orthopedic Engineering, Guangdong Provincial Research Center for Artificial Intelligence and Digital Orthopedic Technology, Shenzhen Second People's Hospital (The First Hospital Affiliated to Shenzhen University, Health Science Center), Shenzhen, China.,Clinical Medicine Department, School of Medicine, University of South China, Hengyang, China
| | - Sun Wei
- Shenzhen Key Laboratory of Tissue Engineering, Shenzhen Laboratory of Digital Orthopedic Engineering, Guangdong Provincial Research Center for Artificial Intelligence and Digital Orthopedic Technology, Shenzhen Second People's Hospital (The First Hospital Affiliated to Shenzhen University, Health Science Center), Shenzhen, China
| | - Duan Li
- Shenzhen Key Laboratory of Tissue Engineering, Shenzhen Laboratory of Digital Orthopedic Engineering, Guangdong Provincial Research Center for Artificial Intelligence and Digital Orthopedic Technology, Shenzhen Second People's Hospital (The First Hospital Affiliated to Shenzhen University, Health Science Center), Shenzhen, China
| | - Wencui Li
- Shenzhen Key Laboratory of Tissue Engineering, Shenzhen Laboratory of Digital Orthopedic Engineering, Guangdong Provincial Research Center for Artificial Intelligence and Digital Orthopedic Technology, Shenzhen Second People's Hospital (The First Hospital Affiliated to Shenzhen University, Health Science Center), Shenzhen, China
| | - Wang Daping
- Shenzhen Key Laboratory of Tissue Engineering, Shenzhen Laboratory of Digital Orthopedic Engineering, Guangdong Provincial Research Center for Artificial Intelligence and Digital Orthopedic Technology, Shenzhen Second People's Hospital (The First Hospital Affiliated to Shenzhen University, Health Science Center), Shenzhen, China.,Clinical Medicine Department, School of Medicine, University of South China, Hengyang, China
| | - Murad Alahdal
- Shenzhen Key Laboratory of Tissue Engineering, Shenzhen Laboratory of Digital Orthopedic Engineering, Guangdong Provincial Research Center for Artificial Intelligence and Digital Orthopedic Technology, Shenzhen Second People's Hospital (The First Hospital Affiliated to Shenzhen University, Health Science Center), Shenzhen, China.,Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, China.,Department of Medical Laboratories, Hodeidah University, Al Hudaydah, Yemen
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24
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Hasegawa H, Wei KY, Thomas M, Li P, Kinderman F, Franey H, Liu L, Jacobsen F. Light chain subunit of a poorly soluble human IgG2λ crystallizes in physiological pH environment both in cellulo and in vitro. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2021; 1868:119078. [PMID: 34118277 DOI: 10.1016/j.bbamcr.2021.119078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 05/17/2021] [Accepted: 06/07/2021] [Indexed: 11/28/2022]
Abstract
Prominent inclusion bodies can develop in the endoplasmic reticulum (ER) when overexpressed antibodies possess intrinsically high condensation propensities. These observations suggest that antibodies deemed to show notable solubility problems may reveal such characteristics preemptively in the form of ER-associated inclusion bodies during antibody overexpression. To define the relationships between solubility problems and inclusion body phenotypes, we investigated the biosynthesis of a model human IgG2λ that shows severe opalescence in an acidic formulation buffer yet retains high solubility at physiological pH. Consistent with the pH-dependent solubility characteristics, the model antibody did not induce notable inclusion body in the physiological pH environment of the ER lumen. However, when individual subunit chains of the antibody were expressed separately, the light chain (LC) spontaneously induced notable crystal-like inclusion bodies in the ER. The LC crystallization event was readily reproducible in vitro by simply concentrating the purified LC protein at physiological pH. Two independent structural determinants for the LC crystallization were identified through rational mutagenesis approach by monitoring the effect of amino acid substitutions on intracellular LC crystallogenesis. The effect of mutations on crystallization was also recapitulated in vitro using purified LC proteins. Importantly, when introduced directly into the model antibody, a mutation that prevents the LC crystallization remediated the antibody's solubility problem without compromising the secretory output or antigen binding. These results illustrate that the ER can serve as a "physiological test tube" that not only reports secretory cargo's high condensation propensity at physiological pH, but also provides an orthogonal method that guides antibody engineering strategy.
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Affiliation(s)
- Haruki Hasegawa
- Department of Therapeutic Discovery, Amgen Inc., South San Francisco, CA 94080, USA.
| | - Kathy Y Wei
- Department of Therapeutic Discovery, Amgen Inc., South San Francisco, CA 94080, USA
| | - Melissa Thomas
- Department of Therapeutic Discovery, Amgen Inc., South San Francisco, CA 94080, USA
| | - Peng Li
- Department of Therapeutic Discovery, Amgen Inc., South San Francisco, CA 94080, USA
| | - Francis Kinderman
- Department of Process Development, Amgen Inc., Thousand Oaks, CA 91320, USA
| | - Heather Franey
- Department of Process Development, Amgen Inc., Thousand Oaks, CA 91320, USA
| | - Ling Liu
- Department of Therapeutic Discovery, Amgen Inc., Thousand Oaks, CA 91320, USA
| | - Frederick Jacobsen
- Department of Therapeutic Discovery, Amgen Inc., Thousand Oaks, CA 91320, USA
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Araújo de Melo Campos JT, Dantas de Medeiros JL, Cardoso de Melo ME, Alvares da Silva M, Oliveira de Sena M, Sales Craveiro Sarmento A, Fassarella Agnez Lima L, de Freitas Fregonezi GA, Gomes Lima J. Endoplasmic reticulum stress and muscle dysfunction in congenital lipodystrophies. Biochim Biophys Acta Mol Basis Dis 2021; 1867:166120. [PMID: 33713793 DOI: 10.1016/j.bbadis.2021.166120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 03/05/2021] [Accepted: 03/08/2021] [Indexed: 01/17/2023]
Abstract
Lipodystrophy syndromes are a group of rare diseases related to the pathological impairment of adipose tissue and metabolic comorbidities, including dyslipidemia, diabetes, insulin resistance, hypoleptinemia, and hypoadiponectinemia. They can be categorized as partial or generalized according to the degree of fat loss, and inherited or acquired disorders, if they are associated with genetic mutations or are related to autoimmunity, respectively. Some types of lipodystrophies have been associated with changes in both redox and endoplasmic reticulum (ER) homeostasis as well as muscle dysfunction (MD). Although ER stress (ERS) has been related to muscle dysfunction (MD) in many diseases, there is no data concerning its role in lipodystrophies' muscle physiopathology. Here we focused on congenital lipodystrophies associated with ERS and MD. We also described recent advances in our understanding of the relationships among ERS, MD, and genetic lipodystrophies, highlighting the adiponectin-protective roles.
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Affiliation(s)
- Julliane Tamara Araújo de Melo Campos
- Laboratório de Biologia Molecular e Genômica, Departamento de Biologia Celular e Genética, Centro de Biociências, Universidade Federal do Rio Grande do Norte, Natal, RN, Brazil.
| | - Jorge Luiz Dantas de Medeiros
- PneumoCardioVascular Lab/HUOL, Hospital Universitário Onofre Lopes, Empresa Brasileira de Serviços Hospitalares and Departamento de Fisioterapia, Universidade Federal do Rio Grande do Norte, Natal, RN, Brazil.
| | - Maria Eduarda Cardoso de Melo
- Laboratório de Biologia Molecular e Genômica, Departamento de Biologia Celular e Genética, Centro de Biociências, Universidade Federal do Rio Grande do Norte, Natal, RN, Brazil
| | - Monique Alvares da Silva
- Laboratório de Biologia Molecular e Genômica, Departamento de Biologia Celular e Genética, Centro de Biociências, Universidade Federal do Rio Grande do Norte, Natal, RN, Brazil
| | - Matheus Oliveira de Sena
- Laboratório de Biologia Molecular e Genômica, Departamento de Biologia Celular e Genética, Centro de Biociências, Universidade Federal do Rio Grande do Norte, Natal, RN, Brazil
| | - Aquiles Sales Craveiro Sarmento
- Unidade de Laboratório de Análises Clínicas e Anatomia Patológica, Hospital Universitário de Lagarto (HUL)/UFS, Lagarto, SE, Brazil
| | - Lucymara Fassarella Agnez Lima
- Laboratório de Biologia Molecular e Genômica, Departamento de Biologia Celular e Genética, Centro de Biociências, Universidade Federal do Rio Grande do Norte, Natal, RN, Brazil
| | - Guilherme Augusto de Freitas Fregonezi
- PneumoCardioVascular Lab/HUOL, Hospital Universitário Onofre Lopes, Empresa Brasileira de Serviços Hospitalares and Departamento de Fisioterapia, Universidade Federal do Rio Grande do Norte, Natal, RN, Brazil; Laboratório de Inovação Tecnológica em Reabilitação, Departamento de Fisioterapia, Universidade Federal do Rio Grande do Norte, Natal, RN, Brazil
| | - Josivan Gomes Lima
- Departamento de Medicina Clínica, Hospital Universitário Onofre Lopes (HUOL)/UFRN, Natal, RN, Brazil
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van Anken E, Bakunts A, Hu CCA, Janssens S, Sitia R. Molecular Evaluation of Endoplasmic Reticulum Homeostasis Meets Humoral Immunity. Trends Cell Biol 2021; 31:529-541. [PMID: 33685797 DOI: 10.1016/j.tcb.2021.02.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 02/02/2021] [Accepted: 02/03/2021] [Indexed: 12/16/2022]
Abstract
The biosynthesis of about one third of the human proteome, including membrane receptors and secreted proteins, occurs in the endoplasmic reticulum (ER). Conditions that perturb ER homeostasis activate the unfolded protein response (UPR). An 'optimistic' UPR output aims at restoring homeostasis by reinforcement of machineries that guarantee efficiency and fidelity of protein biogenesis in the ER. Yet, once the UPR 'deems' that ER homeostatic readjustment fails, it transitions to a 'pessimistic' output, which, depending on the cell type, will result in apoptosis. In this article, we discuss emerging concepts on how the UPR 'evaluates' ER stress, how the UPR is repurposed, in particular in B cells, and how UPR-driven counter-selection of cells undergoing homeostatic failure serves organismal homeostasis and humoral immunity.
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Affiliation(s)
- Eelco van Anken
- Division of Genetics and Cell Biology, San Raffaele Scientific Institute, Milan, Italy; Vita-Salute San Raffaele University, Milan, Italy.
| | - Anush Bakunts
- Division of Genetics and Cell Biology, San Raffaele Scientific Institute, Milan, Italy
| | | | - Sophie Janssens
- Laboratory for Endoplasmic Reticulum (ER) Stress and Inflammation, VIB Center for Inflammation Research, and Department of Internal Medicine and Pediatrics, Ghent University, Ghent, Belgium
| | - Roberto Sitia
- Division of Genetics and Cell Biology, San Raffaele Scientific Institute, Milan, Italy; Vita-Salute San Raffaele University, Milan, Italy
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27
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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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28
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Féral K, Jaud M, Philippe C, Di Bella D, Pyronnet S, Rouault-Pierre K, Mazzolini L, Touriol C. ER Stress and Unfolded Protein Response in Leukemia: Friend, Foe, or Both? Biomolecules 2021; 11:biom11020199. [PMID: 33573353 PMCID: PMC7911881 DOI: 10.3390/biom11020199] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 01/19/2021] [Accepted: 01/25/2021] [Indexed: 12/15/2022] Open
Abstract
The unfolded protein response (UPR) is an evolutionarily conserved adaptive signaling pathway triggered by a stress of the endoplasmic reticulum (ER) lumen compartment, which is initiated by the accumulation of unfolded proteins. This response, mediated by three sensors-Inositol Requiring Enzyme 1 (IRE1), Activating Transcription Factor 6 (ATF6), and Protein Kinase RNA-Like Endoplasmic Reticulum Kinase (PERK)—allows restoring protein homeostasis and maintaining cell survival. UPR represents a major cytoprotective signaling network for cancer cells, which frequently experience disturbed proteostasis owing to their rapid proliferation in an usually unfavorable microenvironment. Increased basal UPR also participates in the resistance of tumor cells against chemotherapy. UPR activation also occurs during hematopoiesis, and growing evidence supports the critical cytoprotective role played by ER stress in the emergence and proliferation of leukemic cells. In case of severe or prolonged stress, pro-survival UPR may however evolve into a cell death program called terminal UPR. Interestingly, a large number of studies have revealed that the induction of proapoptotic UPR can also strongly contribute to the sensitization of leukemic cells to chemotherapy. Here, we review the current knowledge on the consequences of the deregulation of UPR signaling in leukemias and their implications for the treatment of these diseases.
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Affiliation(s)
- Kelly Féral
- Inserm UMR1037-Cancer Research Center of Toulouse, 2 avenue Hubert Curien, Oncopole entrée C, CS 53717, 31037 Toulouse, France; (K.F.); (M.J.); (S.P.)
- Université Toulouse III Paul-Sabatier, F-31000 Toulouse, France
| | - Manon Jaud
- Inserm UMR1037-Cancer Research Center of Toulouse, 2 avenue Hubert Curien, Oncopole entrée C, CS 53717, 31037 Toulouse, France; (K.F.); (M.J.); (S.P.)
- Université Toulouse III Paul-Sabatier, F-31000 Toulouse, France
| | - Céline Philippe
- Barts Cancer Institute, Queen Mary University of London, London E1 4NS, UK; (C.P.); (D.D.B.); (K.R.-P.)
| | - Doriana Di Bella
- Barts Cancer Institute, Queen Mary University of London, London E1 4NS, UK; (C.P.); (D.D.B.); (K.R.-P.)
| | - Stéphane Pyronnet
- Inserm UMR1037-Cancer Research Center of Toulouse, 2 avenue Hubert Curien, Oncopole entrée C, CS 53717, 31037 Toulouse, France; (K.F.); (M.J.); (S.P.)
- Université Toulouse III Paul-Sabatier, F-31000 Toulouse, France
| | - Kevin Rouault-Pierre
- Barts Cancer Institute, Queen Mary University of London, London E1 4NS, UK; (C.P.); (D.D.B.); (K.R.-P.)
| | - Laurent Mazzolini
- Inserm UMR1037-Cancer Research Center of Toulouse, 2 avenue Hubert Curien, Oncopole entrée C, CS 53717, 31037 Toulouse, France; (K.F.); (M.J.); (S.P.)
- CNRS ERL5294, CRCT, F-31037 Toulouse, France
- Correspondence: (L.M.); (C.T.)
| | - Christian Touriol
- Inserm UMR1037-Cancer Research Center of Toulouse, 2 avenue Hubert Curien, Oncopole entrée C, CS 53717, 31037 Toulouse, France; (K.F.); (M.J.); (S.P.)
- Université Toulouse III Paul-Sabatier, F-31000 Toulouse, France
- Correspondence: (L.M.); (C.T.)
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29
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Evolution and function of the epithelial cell-specific ER stress sensor IRE1β. Mucosal Immunol 2021; 14:1235-1246. [PMID: 34075183 PMCID: PMC8528705 DOI: 10.1038/s41385-021-00412-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 04/30/2021] [Accepted: 05/01/2021] [Indexed: 02/04/2023]
Abstract
Barrier epithelial cells lining the mucosal surfaces of the gastrointestinal and respiratory tracts interface directly with the environment. As such, these tissues are continuously challenged to maintain a healthy equilibrium between immunity and tolerance against environmental toxins, food components, and microbes. An extracellular mucus barrier, produced and secreted by the underlying epithelium plays a central role in this host defense response. Several dedicated molecules with a unique tissue-specific expression in mucosal epithelia govern mucosal homeostasis. Here, we review the biology of Inositol-requiring enzyme 1β (IRE1β), an ER-resident endonuclease and paralogue of the most evolutionarily conserved ER stress sensor IRE1α. IRE1β arose through gene duplication in early vertebrates and adopted functions unique from IRE1α which appear to underlie the basic development and physiology of mucosal tissues.
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30
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Preissler S, Rato C, Yan Y, Perera LA, Czako A, Ron D. Calcium depletion challenges endoplasmic reticulum proteostasis by destabilising BiP-substrate complexes. eLife 2020; 9:62601. [PMID: 33295873 PMCID: PMC7758071 DOI: 10.7554/elife.62601] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Accepted: 12/08/2020] [Indexed: 12/14/2022] Open
Abstract
The metazoan endoplasmic reticulum (ER) serves both as a hub for maturation of secreted proteins and as an intracellular calcium storage compartment, facilitating calcium-release-dependent cellular processes. ER calcium depletion robustly activates the unfolded protein response (UPR). However, it is unclear how fluctuations in ER calcium impact organellar proteostasis. Here, we report that calcium selectively affects the dynamics of the abundant metazoan ER Hsp70 chaperone BiP, by enhancing its affinity for ADP. In the calcium-replete ER, ADP rebinding to post-ATP hydrolysis BiP-substrate complexes competes with ATP binding during both spontaneous and co-chaperone-assisted nucleotide exchange, favouring substrate retention. Conversely, in the calcium-depleted ER, relative acceleration of ADP-to-ATP exchange favours substrate release. These findings explain the rapid dissociation of certain substrates from BiP observed in the calcium-depleted ER and suggest a mechanism for tuning ER quality control and coupling UPR activity to signals that mobilise ER calcium in secretory cells.
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Affiliation(s)
- Steffen Preissler
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - Claudia Rato
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - Yahui Yan
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - Luke A Perera
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - Aron Czako
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - David Ron
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
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31
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Bruckmann C, Tamburri S, De Lorenzi V, Doti N, Monti A, Mathiasen L, Cattaneo A, Ruvo M, Bachi A, Blasi F. Mapping the native interaction surfaces of PREP1 with PBX1 by cross-linking mass-spectrometry and mutagenesis. Sci Rep 2020; 10:16809. [PMID: 33033354 PMCID: PMC7545097 DOI: 10.1038/s41598-020-74032-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 09/25/2020] [Indexed: 02/08/2023] Open
Abstract
Both onco-suppressor PREP1 and the oncogene MEIS1 bind to PBX1. This interaction stabilizes the two proteins and allows their translocation into the nucleus and thus their transcriptional activity. Here, we have combined cross-linking mass-spectrometry and systematic mutagenesis to detail the binding geometry of the PBX1-PREP1 (and PBX1-MEIS1) complexes, under native in vivo conditions. The data confirm the existence of two distinct interaction sites within the PBC domain of PBX1 and unravel differences among the highly similar binding sites of MEIS1 and PREP1. The HR2 domain has a fundamental role in binding the PBC-B domain of PBX1 in both PREP1 and MEIS1. The HR1 domain of MEIS1, however, seem to play a less stringent role in PBX1 interaction with respect to that of PREP1. This difference is also reflected by the different binding affinity of the two proteins to PBX1. Although partial, this analysis provides for the first time some ideas on the tertiary structure of the complexes not available before. Moreover, the extensive mutagenic analysis of PREP1 identifies the role of individual hydrophobic HR1 and HR2 residues, both in vitro and in vivo.
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Affiliation(s)
- Chiara Bruckmann
- IFOM (Foundation FIRC Institute of Molecular Oncology), Via Adamello 16, 20139, Milan, Italy.
| | - Simone Tamburri
- IFOM (Foundation FIRC Institute of Molecular Oncology), Via Adamello 16, 20139, Milan, Italy
- Department of Experimental Oncology, European Institute of Oncology, Via Adamello 16, 20139, Milan, Italy
| | - Valentina De Lorenzi
- IFOM (Foundation FIRC Institute of Molecular Oncology), Via Adamello 16, 20139, Milan, Italy
- Center for Nanotechnology Innovation@NEST, Istituto Italiano di Tecnologia, Piazza San Silvestro 12, 56124, Pisa, Italy
| | - Nunzianna Doti
- Institute of Biostructures and Bioimaging (IBB)-CNR, Via Mezzocannone 16, 80134, Naples, Italy
| | - Alessandra Monti
- Institute of Biostructures and Bioimaging (IBB)-CNR, Via Mezzocannone 16, 80134, Naples, Italy
| | - Lisa Mathiasen
- IFOM (Foundation FIRC Institute of Molecular Oncology), Via Adamello 16, 20139, Milan, Italy
| | - Angela Cattaneo
- IFOM (Foundation FIRC Institute of Molecular Oncology), Via Adamello 16, 20139, Milan, Italy
- Cogentech S.R.L. Benefit Corporation IT, Via Adamello 16, 20139, Milan, Italy
| | - Menotti Ruvo
- Institute of Biostructures and Bioimaging (IBB)-CNR, Via Mezzocannone 16, 80134, Naples, Italy
| | - Angela Bachi
- IFOM (Foundation FIRC Institute of Molecular Oncology), Via Adamello 16, 20139, Milan, Italy
| | - Francesco Blasi
- IFOM (Foundation FIRC Institute of Molecular Oncology), Via Adamello 16, 20139, Milan, Italy.
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32
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Intestinal Immune Homeostasis and Inflammatory Bowel Disease: A Perspective on Intracellular Response Mechanisms. GASTROINTESTINAL DISORDERS 2020. [DOI: 10.3390/gidisord2030024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The pathogenesis of inflammatory bowel disease (IBD) involves perturbation of intestinal immune homeostasis in genetically susceptible individuals. A mutual interplay between intestinal epithelial cells (IECs) and gut resident microbes maintains a homeostatic environment across the gut. An idiopathic gastrointestinal (GI) complication triggers aberrant physiological stress in the epithelium and peripheral myeloid cells, leading to a chronic inflammatory condition. Indeed, events in the endoplasmic reticulum (ER) and mitochondria contribute to orchestrating intracellular mechanisms such as the unfolded protein response (UPR) and oxidative stress, respectively, to resolve aberrant cellular stress. This review highlights the signaling cascades encrypted within ER and mitochondria in IECs and/or myeloid cells to dissipate chronic stress in maintaining intestinal homeostasis.
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33
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Evidence for Enhanced Exosome Production in Aromatase Inhibitor-Resistant Breast Cancer Cells. Int J Mol Sci 2020; 21:ijms21165841. [PMID: 32823947 PMCID: PMC7461508 DOI: 10.3390/ijms21165841] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Revised: 08/06/2020] [Accepted: 08/13/2020] [Indexed: 01/08/2023] Open
Abstract
Aromatase inhibitors (AIs) represent the standard anti-hormonal therapy for post-menopausal estrogen receptor-positive breast cancer, but their efficacy is limited by the emergence of AI resistance (AIR). Exosomes act as vehicles to engender cancer progression and drug resistance. The goal of this work was to study exosome contribution in AIR mechanisms, using estrogen-dependent MCF-7 breast cancer cells as models and MCF-7 LTED (Long-Term Estrogen Deprived) subline, modeling AIR. We found that exosome secretion was significantly increased in MCF-7 LTED cells compared to MCF-7 cells. MCF-7 LTED cells also exhibited a higher amount of exosomal RNA and proteins than MCF-7 cells. Proteomic analysis revealed significant alterations in the cellular proteome. Indeed, we showed an enrichment of proteins frequently identified in exosomes in MCF-7 LTED cells. The most up-regulated proteins in MCF-7 LTED cells were represented by Rab GTPases, important vesicle transport-regulators in cancer, that are significantly mapped in “small GTPase-mediated signal transduction”, “protein transport” and “vesicle-mediated transport” Gene Ontology categories. Expression of selected Rab GTPases was validated by immunoblotting. Collectively, we evidence, for the first time, that AIR breast cancer cells display an increased capability to release exosomes, which may be associated with an enhanced Rab GTPase expression. These data provide the rationale for further studies directed at clarifying exosome’s role on endocrine therapy, with the aim to offer relevant markers and druggable therapeutic targets for the management of hormone-resistant breast cancers.
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34
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Larburu N, Adams CJ, Chen CS, Nowak PR, Ali MMU. Mechanism of Hsp70 specialized interactions in protein translocation and the unfolded protein response. Open Biol 2020; 10:200089. [PMID: 32810420 PMCID: PMC7479934 DOI: 10.1098/rsob.200089] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Accepted: 07/07/2020] [Indexed: 01/17/2023] Open
Abstract
Hsp70 chaperones interact with substrate proteins in a coordinated fashion that is regulated by nucleotides and enhanced by assisting cochaperones. There are numerous homologues and isoforms of Hsp70 that participate in a wide variety of cellular functions. This diversity can facilitate adaption or specialization based on particular biological activity and location within the cell. In this review, we highlight two specialized binding partner proteins, Tim44 and IRE1, that interact with Hsp70 at the membrane in order to serve their respective roles in protein translocation and unfolded protein response signalling. Recent mechanistic data suggest analogy in the way the two Hsp70 homologues (BiP and mtHsp70) can bind and release from IRE1 and Tim44 upon substrate engagement. These shared mechanistic features may underlie how Hsp70 interacts with specialized binding partners and may extend our understanding of the mechanistic repertoire that Hsp70 chaperones possess.
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Affiliation(s)
| | | | | | | | - Maruf M. U. Ali
- Department of Life Sciences, Sir Ernst Chain Building, Imperial College London, London SW7 2AZ, UK
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35
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Jumaa H, Caganova M, McAllister EJ, Hoenig L, He X, Saltukoglu D, Brenker K, Köhler M, Leben R, Hauser AE, Niesner R, Rajewsky K, Reth M, Jellusova J. Immunoglobulin expression in the endoplasmic reticulum shapes the metabolic fitness of B lymphocytes. Life Sci Alliance 2020; 3:3/6/e202000700. [PMID: 32341085 PMCID: PMC7190274 DOI: 10.26508/lsa.202000700] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 04/10/2020] [Accepted: 04/15/2020] [Indexed: 11/24/2022] Open
Abstract
The major function of B lymphocytes is to sense antigens and to produce protective antibodies after activation. This function requires the expression of a B-cell antigen receptor (BCR), and evolutionary conserved mechanisms seem to exist that ensure that B cells without a BCR do not develop nor survive in the periphery. Here, we show that the loss of BCR expression on Burkitt lymphoma cells leads to decreased mitochondrial function and impaired metabolic flexibility. Strikingly, this phenotype does not result from the absence of a classical Syk-dependent BCR signal but rather from compromised ER expansion. We show that the reexpression of immunoglobulins (Ig) in the absence of the BCR signaling subunits Igα and Igβ rescues the observed metabolic defects. We demonstrate that immunoglobulin expression is needed to maintain ER homeostasis not only in lymphoma cells but also in resting B cells. Our study provides evidence that the expression of BCR components, which is sensed in the ER and shapes mitochondrial function, represents a novel mechanism of metabolic control in B cells.
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Affiliation(s)
- Huda Jumaa
- BIOSS Centre for Biological Signalling Studies and Centre For Integrative Biological Signalling Studies, Albert Ludwigs University of Freiburg, Freiburg, Germany.,Department of Molecular Immunology, Institute of Biology III at the Faculty of Biology, Albert Ludwigs University of Freiburg, Freiburg, Germany
| | - Marieta Caganova
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin-Buch, Germany
| | - Ellen J McAllister
- BIOSS Centre for Biological Signalling Studies and Centre For Integrative Biological Signalling Studies, Albert Ludwigs University of Freiburg, Freiburg, Germany.,Department of Molecular Immunology, Institute of Biology III at the Faculty of Biology, Albert Ludwigs University of Freiburg, Freiburg, Germany
| | | | - Xiaocui He
- Department of Molecular Immunology, Institute of Biology III at the Faculty of Biology, Albert Ludwigs University of Freiburg, Freiburg, Germany
| | - Deniz Saltukoglu
- BIOSS Centre for Biological Signalling Studies and Centre For Integrative Biological Signalling Studies, Albert Ludwigs University of Freiburg, Freiburg, Germany.,Department of Molecular Immunology, Institute of Biology III at the Faculty of Biology, Albert Ludwigs University of Freiburg, Freiburg, Germany
| | - Kathrin Brenker
- Department of Molecular Immunology, Institute of Biology III at the Faculty of Biology, Albert Ludwigs University of Freiburg, Freiburg, Germany
| | - Markus Köhler
- Biophysical Analytics, Deutsches Rheuma-Forschungszentrum, A Leibniz Institute, Berlin, Germany
| | - Ruth Leben
- Dynamic and Functional In Vivo Imaging, Veterinary Medicine, Freie Universität Berlin, Berlin, Germany.,Biophysical Analytics, Deutsches Rheuma-Forschungszentrum, A Leibniz Institute, Berlin, Germany
| | - Anja E Hauser
- Immune Dynamics Deutsches Rheuma-Forschungszentrum, A Leibniz Institute, Berlin, Germany.,Immune Dynamics, Rheumatology and Clinical Immunology, Charité-Universitätsmedizin, Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Raluca Niesner
- Dynamic and Functional In Vivo Imaging, Veterinary Medicine, Freie Universität Berlin, Berlin, Germany.,Biophysical Analytics, Deutsches Rheuma-Forschungszentrum, A Leibniz Institute, Berlin, Germany
| | - Klaus Rajewsky
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin-Buch, Germany
| | - Michael Reth
- BIOSS Centre for Biological Signalling Studies and Centre For Integrative Biological Signalling Studies, Albert Ludwigs University of Freiburg, Freiburg, Germany.,Department of Molecular Immunology, Institute of Biology III at the Faculty of Biology, Albert Ludwigs University of Freiburg, Freiburg, Germany
| | - Julia Jellusova
- BIOSS Centre for Biological Signalling Studies and Centre For Integrative Biological Signalling Studies, Albert Ludwigs University of Freiburg, Freiburg, Germany .,Department of Molecular Immunology, Institute of Biology III at the Faculty of Biology, Albert Ludwigs University of Freiburg, Freiburg, Germany
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36
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Gilljam KM, Holm KL, Zahoor M, Centonze FG, Farhan H, Blomhoff HK. Differential Effects of Reactive Oxygen Species on IgG versus IgM Levels in TLR-Stimulated B Cells. THE JOURNAL OF IMMUNOLOGY 2020; 204:2133-2142. [PMID: 32188759 DOI: 10.4049/jimmunol.1901131] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Accepted: 02/11/2020] [Indexed: 12/24/2022]
Abstract
It is becoming increasingly evident that reactive oxygen species (ROS) have critical roles as "second messengers" in cell signaling. In B cells, ROS can be generated either as a byproduct of mitochondrial respiration, as a result of the endoplasmic reticulum stress response induced by high production of Igs, or by the activation of NADPH oxidase (NOX) complexes. Having previously shown that costimulation of B cells via TLR 9 and the TLR-related receptor RP105 drives maturation of human peripheral blood B cells into Ig-producing cells, we aimed to study the role of ROS generated during this vital process. To this end, the ROS levels were either reduced by the NOX inhibitor VAS2870 or by the ROS scavenger N-acetyl cysteine (NAC). We revealed that TLR9/RP105-mediated stimulation of human B cells involved a rapid activation of NOX. Moreover, VAS2870 blocked the TLR9/RP105-induced B cell activation and thereby all Ig production. Importantly, we showed that ROS targeted by NAC was selectively required for IgG but not for IgM production. The endoplasmic reticulum stress response in the TLR9/RP105-stimulated cells was higher in IgG+ than in IgG- cells and was reduced by NAC in IgG+ cells only. Of note, we revealed that substantially higher levels of IgG than IgM were produced per cell and that IgG+ cells produced significantly higher ROS levels than IgG- cells. Taken together, our results imply that NAC-targeted ROS may be particularly important for sustaining the high Ig production in IgG+ B cells.
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Affiliation(s)
- Karin Margaretha Gilljam
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, 0372 Oslo, Norway
| | - Kristine Lillebø Holm
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, 0372 Oslo, Norway
| | - Muhammad Zahoor
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, 0372 Oslo, Norway
| | - Federica Grazia Centonze
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, 0372 Oslo, Norway
| | - Hesso Farhan
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, 0372 Oslo, Norway
| | - Heidi Kiil Blomhoff
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, 0372 Oslo, Norway
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37
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Yu J, Li T, Liu Y, Wang X, Zhang J, Wang X, Shi G, Lou J, Wang L, Wang CC, Wang L. Phosphorylation switches protein disulfide isomerase activity to maintain proteostasis and attenuate ER stress. EMBO J 2020; 39:e103841. [PMID: 32149426 DOI: 10.15252/embj.2019103841] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 02/07/2020] [Accepted: 02/11/2020] [Indexed: 12/11/2022] Open
Abstract
Accumulated unfolded proteins in the endoplasmic reticulum (ER) trigger the unfolded protein response (UPR) to increase ER protein folding capacity. ER proteostasis and UPR signaling need to be regulated in a precise and timely manner. Here, we identify phosphorylation of protein disulfide isomerase (PDI), one of the most abundant and critical folding catalysts in the ER, as an early event during ER stress. The secretory pathway kinase Fam20C phosphorylates Ser357 of PDI and responds rapidly to various ER stressors. Phosphorylation of Ser357 induces an open conformation of PDI and turns it from a "foldase" into a "holdase", which is critical for preventing protein misfolding in the ER. Phosphorylated PDI also binds to the lumenal domain of IRE1α, a major UPR signal transducer, and attenuates excessive IRE1α activity. Importantly, PDI-S359A knock-in mice display enhanced IRE1α activation and liver damage under acute ER stress. We conclude that the Fam20C-PDI axis constitutes a post-translational response to maintain ER proteostasis and plays a vital role in protecting against ER stress-induced cell death.
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Affiliation(s)
- Jiaojiao Yu
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Tao Li
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Yu Liu
- CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China
| | - Xi Wang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Jianchao Zhang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Xi'e Wang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Guizhi Shi
- Laboratory Animal Center of Institute of Biophysics, Chinese Academy of Sciences, Aviation General Hospital of Beijing, University of Chinese Academy of Sciences, Beijing, China
| | - Jizhong Lou
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China.,Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Likun Wang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Chih-Chen Wang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Lei Wang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
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38
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Hinte F, van Anken E, Tirosh B, Brune W. Repression of viral gene expression and replication by the unfolded protein response effector XBP1u. eLife 2020; 9:51804. [PMID: 32065579 PMCID: PMC7082126 DOI: 10.7554/elife.51804] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 02/17/2020] [Indexed: 01/07/2023] Open
Abstract
The unfolded protein response (UPR) is a cellular homeostatic circuit regulating protein synthesis and processing in the ER by three ER-to-nucleus signaling pathways. One pathway is triggered by the inositol-requiring enzyme 1 (IRE1), which splices the X-box binding protein 1 (Xbp1) mRNA, thereby enabling expression of XBP1s. Another UPR pathway activates the activating transcription factor 6 (ATF6). Here we show that murine cytomegalovirus (MCMV), a prototypic β-herpesvirus, harnesses the UPR to regulate its own life cycle. MCMV activates the IRE1-XBP1 pathway early post infection to relieve repression by XBP1u, the product of the unspliced Xbp1 mRNA. XBP1u inhibits viral gene expression and replication by blocking the activation of the viral major immediate-early promoter by XBP1s and ATF6. These findings reveal a redundant function of XBP1s and ATF6 as activators of the viral life cycle, and an unexpected role of XBP1u as a potent repressor of both XBP1s and ATF6-mediated activation. Cells survive by making many different proteins that each carry out specific tasks. To work correctly, each protein must be made and then folded into the right shape. Cells carefully monitor protein folding because unfolded proteins can compromise their viability. A protein called XBP1 is important in controlling how cells respond to unfolded proteins. Normally, cells contain a form of this protein called XBP1u, while increasing numbers of unfolded proteins trigger production of a form called XBP1s. The change from one form to the other is activated by a protein called IRE1. Viruses often manipulate stress responses like the unfolded protein response to help take control of the cell and produce more copies of the virus. Murine cytomegalovirus, which is known as MCMV for short, is a herpes-like virus that infects mice; it stops IRE1 activation and XBP1s production during the later stages of infection. However, research had shown that the unfolded protein response was triggered for a short time at an early stage of infection with MCMV, and it was unclear why this might be. Hinte et al. studied the effect of MCMV on cells grown in the laboratory. The experiments showed that a small dose of cell stress, namely activating the unfolded protein response briefly during early infection, helps to activate genes from the virus that allow it to take over the cell. Together, XBP1s and another protein called ATF6 help to switch on the viral genes. The virus also triggers IRE1 helping to reduce the levels of XBP1u, which could slow down the infection. Later, suppressing the unfolded protein response allows copies of the virus to be made faster to help spread the infection. These findings reveal new details of how viruses precisely manipulate their host cells at different stages of infection. These insights could lead to new ways to manage or prevent viral infections.
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Affiliation(s)
- Florian Hinte
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Eelco van Anken
- Division of Genetics and Cell Biology, San Raffaele Scientific Institute, Milan, Italy.,Università Vita-Salute San Raffaele, Milan, Italy
| | - Boaz Tirosh
- Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University, Jerusalem, Israel
| | - Wolfram Brune
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
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39
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Omer S, Koumangoye R, Delpire E. A mutation in the Na-K-2Cl cotransporter-1 leads to changes in cellular metabolism. J Cell Physiol 2020; 235:7239-7250. [PMID: 32039487 DOI: 10.1002/jcp.29623] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Accepted: 01/27/2020] [Indexed: 12/12/2022]
Abstract
The Na-K-Cl cotransporter-1 (NKCC1), by mediating the electroneutral transport of Na+ , K+ , and Cl- plays an important role in cell volume regulation, epithelial transport, and the control of neuronal excitability. Recently, we reported the first known human mutation in SLC12A2, the gene encoding NKCC1. The 17-year old patient suffers from multiorgan failure. Laboratory tests conducted on muscle and liver biopsies of the patient showed abnormal increase in mitochondrial DNA copy number and increased glycogen levels, indicating the possibility that the transporter may play a role in energy metabolism. Here, we show that fibroblasts isolated from the patient demonstrate a significant increase in mitochondrial respiration, compared to fibroblasts isolated from healthy individuals. Similarly, Madin Darby canine kidney (MDCK) cells transfected with enhanced green fluorescent protein (EGFP)-tagged mutant NKCC1 DNA demonstrated increased mitochondrial respiration when compared to MDCK cells expressing EGFP-tagged wild-type (WT) cotransporter. Direct inhibition of the cotransporter through addition of bumetanide did not change the rate of basal respiration, but led to increased maximal mitochondrial respiration. Fibroblasts extracted from NKCC1WT/DFX and NKCC1DFX/DFX mice also demonstrated a significant elevation in mitochondrial respiration, compared to fibroblasts isolated from their WT littermates. Expression of the mutant protein was associated with an increase in hydrogen peroxide and peroxidase activity and a decrease in messenger RNA transcript levels for protein involved in the unfolded protein response. These data reveal that cells expressing the mutant cotransporter demonstrate increased mitochondrial respiration and behave like they are experiencing a state of starvation.
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Affiliation(s)
- Salma Omer
- Department of Anesthesiology, Vanderbilt University School of Medicine, Nashville, Tennessee.,Neuroscience Graduate Program, Vanderbilt University, Nashville, Tennessee
| | - Rainelli Koumangoye
- Department of Anesthesiology, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Eric Delpire
- Department of Anesthesiology, Vanderbilt University School of Medicine, Nashville, Tennessee.,Neuroscience Graduate Program, Vanderbilt University, Nashville, Tennessee
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40
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Oikonomou C, Hendershot LM. Disposing of misfolded ER proteins: A troubled substrate's way out of the ER. Mol Cell Endocrinol 2020; 500:110630. [PMID: 31669350 PMCID: PMC6911830 DOI: 10.1016/j.mce.2019.110630] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 09/19/2019] [Accepted: 10/20/2019] [Indexed: 12/12/2022]
Abstract
Secreted, plasma membrane, and resident proteins of the secretory pathway are synthesized in the endoplasmic reticulum (ER) where they undergo post-translational modifications, oxidative folding, and subunit assembly in tightly monitored processes. An ER quality control (ERQC) system oversees protein maturation and ensures that only those reaching their native state will continue trafficking into the secretory pathway to reach their final destinations. Those that fail must be recognized and eliminated to maintain ER homeostasis. Two cellular mechanisms have been identified to rid the ER of terminally unfolded, misfolded, and aggregated proteins. ER-associated degradation (ERAD) was discovered nearly 30 years ago and entails the identification of improperly matured secretory pathway proteins and their retrotranslocation to the cytosol for degradation by the ubiquitin-proteasome system. ER-phagy has been more recently described and caters to larger, more complex proteins and protein aggregates that are not readily handled by ERAD. This pathway has unique upstream components and relies on the same downstream effectors of autophagy used in other cellular processes to deliver clients to lysosomes for degradation. In this review, we describe the main elements of ERQC, ERAD, and ER-phagy and focus on recent advances in these fields.
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Affiliation(s)
- Christina Oikonomou
- St. Jude Children's Research Hospital, Memphis, TN, 38104, USA; The University of Tennessee Health Science Center, Memphis, TN, USA
| | - Linda M Hendershot
- St. Jude Children's Research Hospital, Memphis, TN, 38104, USA; The University of Tennessee Health Science Center, Memphis, TN, USA.
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41
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Amin-Wetzel N, Neidhardt L, Yan Y, Mayer MP, Ron D. Unstructured regions in IRE1α specify BiP-mediated destabilisation of the luminal domain dimer and repression of the UPR. eLife 2019; 8:50793. [PMID: 31873072 PMCID: PMC6996924 DOI: 10.7554/elife.50793] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 12/23/2019] [Indexed: 12/15/2022] Open
Abstract
Coupling of endoplasmic reticulum (ER) stress to dimerisation-dependent activation of the UPR transducer IRE1 is incompletely understood. Whilst the luminal co-chaperone ERdj4 promotes a complex between the Hsp70 BiP and IRE1's stress-sensing luminal domain (IRE1LD) that favours the latter's monomeric inactive state and loss of ERdj4 de-represses IRE1, evidence linking these cellular and in vitro observations is presently lacking. We report that enforced loading of endogenous BiP onto endogenous IRE1α repressed UPR signalling in CHO cells and deletions in the IRE1α locus that de-repressed the UPR in cells, encode flexible regions of IRE1LD that mediated BiP-induced monomerisation in vitro. Changes in the hydrogen exchange mass spectrometry profile of IRE1LD induced by ERdj4 and BiP confirmed monomerisation and were consistent with active destabilisation of the IRE1LD dimer. Together, these observations support a competition model whereby waning ER stress passively partitions ERdj4 and BiP to IRE1LD to initiate active repression of UPR signalling.
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Affiliation(s)
- Niko Amin-Wetzel
- Cambridge Institute for Medical Research (CIMR), University of Cambridge, Cambridge, United Kingdom
| | - Lisa Neidhardt
- Cambridge Institute for Medical Research (CIMR), University of Cambridge, Cambridge, United Kingdom
| | - Yahui Yan
- Cambridge Institute for Medical Research (CIMR), University of Cambridge, Cambridge, United Kingdom
| | - Matthias P Mayer
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - David Ron
- Cambridge Institute for Medical Research (CIMR), University of Cambridge, Cambridge, United Kingdom
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42
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Kopp MC, Larburu N, Durairaj V, Adams CJ, Ali MMU. UPR proteins IRE1 and PERK switch BiP from chaperone to ER stress sensor. Nat Struct Mol Biol 2019; 26:1053-1062. [PMID: 31695187 PMCID: PMC6858872 DOI: 10.1038/s41594-019-0324-9] [Citation(s) in RCA: 186] [Impact Index Per Article: 37.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 10/01/2019] [Indexed: 12/24/2022]
Abstract
BiP is a major endoplasmic reticulum (ER) chaperone and is suggested to act as primary sensor in the activation of the unfolded protein response (UPR). How BiP operates as a molecular chaperone and as an ER stress sensor is unknown. Here, by reconstituting components of human UPR, ER stress and BiP chaperone systems, we discover that the interaction of BiP with the luminal domains of UPR proteins IRE1 and PERK switch BiP from its chaperone cycle into an ER stress sensor cycle by preventing the binding of its co-chaperones, with loss of ATPase stimulation. Furthermore, misfolded protein-dependent dissociation of BiP from IRE1 is primed by ATP but not ADP. Our data elucidate a previously unidentified mechanistic cycle of BiP function that explains its ability to act as an Hsp70 chaperone and ER stress sensor.
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Affiliation(s)
- Megan C Kopp
- Department of Life Sciences, Sir Ernst Chain Building, Imperial College London, London, UK
| | - Natacha Larburu
- Department of Life Sciences, Sir Ernst Chain Building, Imperial College London, London, UK
| | - Vinoth Durairaj
- Department of Life Sciences, Sir Ernst Chain Building, Imperial College London, London, UK
| | - Christopher J Adams
- Department of Life Sciences, Sir Ernst Chain Building, Imperial College London, London, UK
| | - Maruf M U Ali
- Department of Life Sciences, Sir Ernst Chain Building, Imperial College London, London, UK.
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43
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van Ziel AM, Wolzak K, Nölle A, Hoetjes PJ, Berenjeno-Correa E, van Anken E, Struys EA, Scheper W. No evidence for cell-to-cell transmission of the unfolded protein response in cell culture. J Neurochem 2019; 152:208-220. [PMID: 31442299 PMCID: PMC7003778 DOI: 10.1111/jnc.14856] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 07/31/2019] [Accepted: 08/12/2019] [Indexed: 12/18/2022]
Abstract
The unfolded protein response (UPR) is one of the major cell‐autonomous proteostatic stress responses. The UPR has been implicated in the pathogenesis of neurodegenerative diseases and is therefore actively investigated as therapeutic target. In this respect, cell non‐autonomous effects of the UPR including the reported cell‐to‐cell transmission of UPR activity may be highly important. A pharmaca‐based UPR induction was employed to generate conditioned media (CM) from CM‐donating neuronal (‘donor’) cells (SK‐N‐SH and primary mouse neurons). As previously reported, upon subsequent transfer of CM to naive neuronal ‘acceptor’ cells, we confirmed UPR target mRNA and protein expression by qPCR and automated microscopy. However, UPR target gene expression was also induced in the absence of donor cells, indicating carry‐over of pharmaca. Genetic induction of single pathways of the UPR in donor cells did not result in UPR transmission to acceptor cells. Moreover, no transmission was detected upon full UPR activation by nutrient deprivation or inducible expression of the heavy chain of immunoglobulin M in donor HeLa cells. In addition, in direct co‐culture of donor cells expressing the immunoglobulin M heavy chain and fluorescent UPR reporter acceptor HeLa cells, UPR transmission was not observed. In conclusion, carry‐over of pharmaca is a major confounding factor in pharmaca‐based UPR transmission protocols that are therefore unsuitable to study cell‐to‐cell UPR transmission. In addition, the absence of UPR transmission in non‐pharmaca‐based models of UPR activation indicates that cell‐to‐cell UPR transmission does not occur in cell culture. ![]()
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Affiliation(s)
- Anna M van Ziel
- Department of Clinical Genetics, Amsterdam University Medical Centers Location VUmc, Amsterdam, The Netherlands.,Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, Vrije Universiteit (VU), Amsterdam, The Netherlands
| | - Kimberly Wolzak
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, Vrije Universiteit (VU), Amsterdam, The Netherlands
| | - Anna Nölle
- Department of Pathology, Amsterdam University Medical Centers Location VUmc, Amsterdam, The Netherlands
| | - Petrus J Hoetjes
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, Vrije Universiteit (VU), Amsterdam, The Netherlands
| | - Ernesto Berenjeno-Correa
- Department of Clinical Genetics, Amsterdam University Medical Centers Location VUmc, Amsterdam, The Netherlands.,Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, Vrije Universiteit (VU), Amsterdam, The Netherlands
| | - Eelco van Anken
- Division of Genetics and Cell Biology, San Raffaele Scientific Institute, Milan, Italy
| | - Eduard A Struys
- Department of Clinical Chemistry, Amsterdam University Medical Centers Location VUmc, Amsterdam, The Netherlands
| | - Wiep Scheper
- Department of Clinical Genetics, Amsterdam University Medical Centers Location VUmc, Amsterdam, The Netherlands.,Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, Vrije Universiteit (VU), Amsterdam, The Netherlands.,Alzheimer Center, Amsterdam University Medical Centers Location VUmc, Amsterdam, The Netherlands
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44
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Stroberg W, Eilertsen J, Schnell S. Information processing by endoplasmic reticulum stress sensors. J R Soc Interface 2019; 16:20190288. [PMID: 31506041 DOI: 10.1098/rsif.2019.0288] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The unfolded protein response (UPR) is a collection of cellular feedback mechanisms that seek to maintain protein folding homeostasis in the endoplasmic reticulum (ER). When the ER is 'stressed', through either high protein folding demand or undersupply of chaperones and foldases, stress sensing proteins in the ER membrane initiate the UPR. Recently, experiments have indicated that these signalling molecules detect stress by being both sequestered by free chaperones and activated by free unfolded proteins. However, it remains unclear what advantage this bidirectional sensor control offers stressed cells. Here, we show that combining positive regulation of sensor activity by unfolded proteins with negative regulation by chaperones allows the sensor to make a more informative measurement of ER stress. The increase in the information capacity of the combined sensing mechanism stems from stretching of the active range of the sensor, at the cost of increased uncertainty due to the integration of multiple signals. These results provide a possible rationale for the evolution of the observed stress-sensing mechanism.
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Affiliation(s)
- Wylie Stroberg
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Justin Eilertsen
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Santiago Schnell
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA.,Department of Computational Medicine and Bioinformatics, University of Michigan Medical School, Ann Arbor, MI, USA
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45
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Berki T, Bakunts A, Duret D, Fabre L, Ladavière C, Orsi A, Charreyre MT, Raimondi A, van Anken E, Favier A. Advanced Fluorescent Polymer Probes for the Site-Specific Labeling of Proteins in Live Cells Using the HaloTag Technology. ACS OMEGA 2019; 4:12841-12847. [PMID: 31460409 PMCID: PMC6682114 DOI: 10.1021/acsomega.9b01643] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 07/16/2019] [Indexed: 06/01/2023]
Abstract
We report the site-specific and covalent bioconjugation of fluorescent polymer chains to proteins in live cells using the HaloTag technology. Polymer chains bearing a Halo-ligand precisely located at their α-chain-end were synthesized in a controlled manner owing to the RAFT polymerization process. They were labeled in lateral position by several organic fluorophores such as AlexaFluor 647. The resulting Halo-ligand polymer probe was finally shown to selectively recognize and label HaloTag proteins present at the membrane of live cells using confocal fluorescence microscopy. Such a polymer bioconjugation approach holds great promises for various applications ranging from cell imaging to cell surface functionalization.
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Affiliation(s)
- Thomas Berki
- Univ
Lyon, Université Lyon 1, INSA de Lyon, CNRS, Laboratoire Ingénierie
des Matériaux Polymères, UMR5223, F-69621 Villeurbanne, France
- Univ
Lyon, Ens de Lyon, CNRS, Laboratoire Joliot-Curie, USR3010, F-69364 Lyon, France
| | - Anush Bakunts
- Division of Genetics and Cell Biology and Experimental
Imaging Center, San Raffaele Scientific
Institute, Milan 20132, Italy
| | - Damien Duret
- Univ
Lyon, Université Lyon 1, INSA de Lyon, CNRS, Laboratoire Ingénierie
des Matériaux Polymères, UMR5223, F-69621 Villeurbanne, France
- Univ
Lyon, Ens de Lyon, CNRS, Laboratoire Joliot-Curie, USR3010, F-69364 Lyon, France
| | - Laura Fabre
- Univ
Lyon, Université Lyon 1, INSA de Lyon, CNRS, Laboratoire Ingénierie
des Matériaux Polymères, UMR5223, F-69621 Villeurbanne, France
| | - Catherine Ladavière
- Univ
Lyon, Université Lyon 1, INSA de Lyon, CNRS, Laboratoire Ingénierie
des Matériaux Polymères, UMR5223, F-69621 Villeurbanne, France
| | - Andrea Orsi
- Division of Genetics and Cell Biology and Experimental
Imaging Center, San Raffaele Scientific
Institute, Milan 20132, Italy
- Università
Vita-Salute San Raffaele, Milan 20132, Italy
| | - Marie-Thérèse Charreyre
- Univ
Lyon, Université Lyon 1, INSA de Lyon, CNRS, Laboratoire Ingénierie
des Matériaux Polymères, UMR5223, F-69621 Villeurbanne, France
- Univ
Lyon, Ens de Lyon, CNRS, Laboratoire Joliot-Curie, USR3010, F-69364 Lyon, France
| | - Andrea Raimondi
- Division of Genetics and Cell Biology and Experimental
Imaging Center, San Raffaele Scientific
Institute, Milan 20132, Italy
| | - Eelco van Anken
- Division of Genetics and Cell Biology and Experimental
Imaging Center, San Raffaele Scientific
Institute, Milan 20132, Italy
- Università
Vita-Salute San Raffaele, Milan 20132, Italy
| | - Arnaud Favier
- Univ
Lyon, Université Lyon 1, INSA de Lyon, CNRS, Laboratoire Ingénierie
des Matériaux Polymères, UMR5223, F-69621 Villeurbanne, France
- Univ
Lyon, Ens de Lyon, CNRS, Laboratoire Joliot-Curie, USR3010, F-69364 Lyon, France
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46
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Ricci D, Marrocco I, Blumenthal D, Dibos M, Eletto D, Vargas J, Boyle S, Iwamoto Y, Chomistek S, Paton JC, Paton AW, Argon Y. Clustering of IRE1α depends on sensing ER stress but not on its RNase activity. FASEB J 2019; 33:9811-9827. [PMID: 31199681 DOI: 10.1096/fj.201801240rr] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The sensors of the unfolded protein response react to endoplasmic reticulum (ER) stress by transient activation of their enzymatic activities, which initiate various signaling cascades. In addition, the sensor IRE1α exhibits stress-induced clustering in a transient time frame similar to activation of its endoRNase activity. Previous work had suggested that the clustering response and RNase activity of IRE1α are functionally linked, but here we show that they are independent of each other and have different behaviors and modes of activation. Although both clustering and the RNase activity are responsive to luminal stress conditions and to depletion of the ER chaperone binding protein, RNase-inactive IRE1α still clusters and, conversely, full RNase activity can be accomplished without clustering. The clusters formed by RNase-inactive IRE1α are much larger and persist longer than those induced by ER stress. Clustering requires autophosphorylation, and an IRE1α mutant whose RNase domain is responsive to ligands that bind the kinase domain forms yet a third type of stress-independent cluster, with distinct physical properties and half-lives. These data suggest that IRE1α clustering can follow distinct pathways upon activation of the sensor.-Ricci, D., Marrocco, I., Blumenthal, D., Dibos, M., Eletto, D., Vargas, J., Boyle, S., Iwamoto, Y., Chomistek, S., Paton, J. C., Paton, A. W., Argon, Y. Clustering of IRE1α depends on sensing ER stress but not on its RNase activity.
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Affiliation(s)
- Daniela Ricci
- Division of Cell Pathology, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Ilaria Marrocco
- Division of Cell Pathology, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Daniel Blumenthal
- Division of Cell Pathology, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Miriam Dibos
- Division of Cell Pathology, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Daniela Eletto
- Division of Cell Pathology, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Jade Vargas
- Division of Cell Pathology, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Sarah Boyle
- Division of Cell Pathology, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Yuichiro Iwamoto
- Division of Cell Pathology, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Steven Chomistek
- Division of Cell Pathology, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - James C Paton
- Department of Molecular and Cellular Biology, University of Adelaide, Adelaide, South Australia, Australia
| | - Adrienne W Paton
- Department of Molecular and Cellular Biology, University of Adelaide, Adelaide, South Australia, Australia
| | - Yair Argon
- Division of Cell Pathology, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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47
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Preissler S, Ron D. Early Events in the Endoplasmic Reticulum Unfolded Protein Response. Cold Spring Harb Perspect Biol 2019; 11:cshperspect.a033894. [PMID: 30396883 PMCID: PMC6442202 DOI: 10.1101/cshperspect.a033894] [Citation(s) in RCA: 104] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The physiological consequences of the unfolded protein response (UPR) are mediated by changes in gene expression. Underlying them are rapid processes involving preexisting components. We review recent insights gained into the regulation of the endoplasmic reticulum (ER) Hsp70 chaperone BiP, whose incorporation into inactive oligomers and reversible AMPylation and de-AMPylation present a first line of response to fluctuating levels of unfolded proteins. BiP activity is tied to the regulation of the UPR transducers by a recently discovered cycle of ER-localized, J protein-mediated formation of a repressive IRE1-BiP complex, whose working we contrast to an alternative model for UPR regulation that relies on direct recognition of unfolded proteins. We conclude with a discussion of mechanisms that repress messenger RNA (mRNA) translation to limit the flux of newly synthesized proteins into the ER, a rapid adaptation that does not rely on new macromolecule biosynthesis.
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48
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Vitale M, Bakunts A, Orsi A, Lari F, Tadè L, Danieli A, Rato C, Valetti C, Sitia R, Raimondi A, Christianson JC, van Anken E. Inadequate BiP availability defines endoplasmic reticulum stress. eLife 2019; 8:41168. [PMID: 30869076 PMCID: PMC6417858 DOI: 10.7554/elife.41168] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 02/13/2019] [Indexed: 12/16/2022] Open
Abstract
How endoplasmic reticulum (ER) stress leads to cytotoxicity is ill-defined. Previously we showed that HeLa cells readjust homeostasis upon proteostatically driven ER stress, triggered by inducible bulk expression of secretory immunoglobulin M heavy chain (μs) thanks to the unfolded protein response (UPR; Bakunts et al., 2017). Here we show that conditions that prevent that an excess of the ER resident chaperone (and UPR target gene) BiP over µs is restored lead to µs-driven proteotoxicity, i.e. abrogation of HRD1-mediated ER-associated degradation (ERAD), or of the UPR, in particular the ATF6α branch. Such conditions are tolerated instead upon removal of the BiP-sequestering first constant domain (CH1) from µs. Thus, our data define proteostatic ER stress to be a specific consequence of inadequate BiP availability, which both the UPR and ERAD redeem.
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Affiliation(s)
- Milena Vitale
- Division of Genetics and Cell Biology, San Raffaele Scientific Institute, Milan, Italy
| | - Anush Bakunts
- Division of Genetics and Cell Biology, San Raffaele Scientific Institute, Milan, Italy
| | - Andrea Orsi
- Division of Genetics and Cell Biology, San Raffaele Scientific Institute, Milan, Italy.,Università Vita-Salute San Raffaele, Milan, Italy
| | - Federica Lari
- Division of Genetics and Cell Biology, San Raffaele Scientific Institute, Milan, Italy.,Ludwig Institute for Cancer Research, University of Oxford, Oxford, United Kingdom
| | - Laura Tadè
- Division of Genetics and Cell Biology, San Raffaele Scientific Institute, Milan, Italy
| | - Alberto Danieli
- Division of Genetics and Cell Biology, San Raffaele Scientific Institute, Milan, Italy
| | - Claudia Rato
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - Caterina Valetti
- Department of Experimental Medicine, University of Genova, Genova, Italy
| | - Roberto Sitia
- Division of Genetics and Cell Biology, San Raffaele Scientific Institute, Milan, Italy.,Università Vita-Salute San Raffaele, Milan, Italy
| | - Andrea Raimondi
- Experimental Imaging Center, San Raffaele Scientific Institute, Milan, Italy
| | - John C Christianson
- Ludwig Institute for Cancer Research, University of Oxford, Oxford, United Kingdom
| | - Eelco van Anken
- Division of Genetics and Cell Biology, San Raffaele Scientific Institute, Milan, Italy.,Università Vita-Salute San Raffaele, Milan, Italy
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49
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Sannino S, Guerriero CJ, Sabnis AJ, Stolz DB, Wallace CT, Wipf P, Watkins SC, Bivona TG, Brodsky JL. Compensatory increases of select proteostasis networks after Hsp70 inhibition in cancer cells. J Cell Sci 2018; 131:jcs.217760. [PMID: 30131440 DOI: 10.1242/jcs.217760] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Accepted: 08/02/2018] [Indexed: 12/13/2022] Open
Abstract
Cancer cells thrive when challenged with proteotoxic stress by inducing components of the protein folding, proteasome, autophagy and unfolded protein response (UPR) pathways. Consequently, specific molecular chaperones have been validated as targets for anti-cancer therapies. For example, inhibition of Hsp70 family proteins (hereafter Hsp70) in rhabdomyosarcoma triggers UPR induction and apoptosis. To define how these cancer cells respond to compromised proteostasis, we compared rhabdomyosarcoma cells that were sensitive (RMS13) or resistant (RMS13-R) to the Hsp70 inhibitor MAL3-101. We discovered that endoplasmic reticulum-associated degradation (ERAD) and autophagy were activated in RMS13-R cells, suggesting that resistant cells overcome Hsp70 ablation by increasing misfolded protein degradation. Indeed, RMS13-R cells degraded ERAD substrates more rapidly than RMS cells and induced the autophagy pathway. Surprisingly, inhibition of the proteasome or ERAD had no effect on RMS13-R cell survival, but silencing of select autophagy components or treatment with autophagy inhibitors restored MAL3-101 sensitivity and led to apoptosis. These data indicate a route through which cancer cells overcome a chaperone-based therapy, define how cells can adapt to Hsp70 inhibition, and demonstrate the value of combined chaperone and autophagy-based therapies.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Sara Sannino
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | | | - Amit J Sabnis
- Department of Pediatrics, University of California, San Francisco, CA 94143, USA.,Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, CA 94143, USA
| | - Donna Beer Stolz
- Department of Medicine, University of California, San Francisco, CA 94143, USA
| | - Callen T Wallace
- Department of Medicine, University of California, San Francisco, CA 94143, USA
| | - Peter Wipf
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Simon C Watkins
- Department of Medicine, University of California, San Francisco, CA 94143, USA
| | - Trever G Bivona
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, CA 94143, USA.,Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Jeffrey L Brodsky
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
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50
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Bergmann TJ, Molinari M. Three branches to rule them all? UPR signalling in response to chemically versus misfolded proteins-induced ER stress. Biol Cell 2018; 110:197-204. [PMID: 29979817 DOI: 10.1111/boc.201800029] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 06/15/2018] [Indexed: 12/16/2022]
Abstract
Study of the unfolded protein responses (UPR) is mainly addressed by challenging eukaryotic cells with chemical compounds that impair calcium, redox or glycan homeostasis. These dramatically alter the endoplasmic reticulum (ER) environment and function, but also trigger pleiotropic effects that may result in multi-organellar failure and cell death. Recent works showed that UPR induced by the accumulation of unfolded polypeptides in the ER lumen drastically differs from chemically induced UPR. Unfolded proteins are tolerated by cells, which activate a finely tuned UPR without entering apoptotic programs. How cells adapt the UPR to the burden of misfolded proteins, what structural features of the accumulating proteins determine UPR intensity and how these mechanisms translate into disease are crucial questions to be address in the future.
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Affiliation(s)
- Timothy J Bergmann
- Università della Svizzera italiana (USI), Faculty of Biomedical Sciences, Institute for Research in Biomedicine, Bellinzona, Switzerland
| | - Maurizio Molinari
- Università della Svizzera italiana (USI), Faculty of Biomedical Sciences, Institute for Research in Biomedicine, Bellinzona, Switzerland.,École Polytechnique Fédérale de Lausanne, School of Life Sciences, Lausanne, Switzerland
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