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Bianchi ME, Rubartelli A, Sitia R. Preferential Secretion of Oxidation-Sensitive Proteins by Unconventional Pathways: Why is This Important for Inflammation? Antioxid Redox Signal 2024. [PMID: 38916186 DOI: 10.1089/ars.2024.0554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 06/26/2024]
Abstract
Significance: Fidelity of intercellular communication depends on unambiguous interactions between protein ligands and membrane receptors. Most proteins destined to the extracellular space adopt the required three-dimensional shape as they travel through the endoplasmic reticulum (ER), Golgi complex, and other organelles of the exocytic pathway. However, some proteins, many of which are involved in inflammation, avoid this classical secretory route and follow unconventional pathways to leave the cell. Recent Advances: Stringent quality control systems operate in the ER and cis-Golgi, restricting transport to native conformers, devoid of non-native disulfides and/or reactive thiols. However, some proteins released by living cells require reduced cysteines to exert their extracellular function(s). Remarkably, these proteins lack the secretory signal sequence normally required by secretory proteins for translocation into the ER lumen. Critical Issues: Why do interleukin-1β, high mobility group box 1, and other proinflammatory proteins avoid the ER-Golgi route to reach the intercellular space? These proteins require reactive cysteines for exerting their function. Therefore, eluding thiol-mediated quality control along the exocytic pathway is likely one of the main reasons why extracellular proteins that need to be reduced utilize unconventional pathways of secretion, where a quality control aimed at oxidating native cysteines is not present. Future Directions: Particularly under stress conditions, cells release redox-active enzymes and nonprotein thiol compounds that exert an extracellular control of redox-sensitive protein activity, shaping inflammatory responses. This post-secretion, redox-dependent editing of protein messages is still largely undefined. Understanding the underlying mechanistic events will hopefully provide new tools to control inflammation.
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Affiliation(s)
- Marco E Bianchi
- Division of Genetics and Cell Biology, Vita-Salute San Raffaele University and IRCCS San Raffaele Hospital, Milano, Italy
| | - Anna Rubartelli
- Division of Genetics and Cell Biology, Vita-Salute San Raffaele University and IRCCS San Raffaele Hospital, Milano, Italy
| | - Roberto Sitia
- Division of Genetics and Cell Biology, Vita-Salute San Raffaele University and IRCCS San Raffaele Hospital, Milano, Italy
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2
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Oliveira PVS, Dalla Torre M, Debbas V, Orsi A, Laurindo FRM, Sitia R. Transport of protein disulfide isomerase from the endoplasmic reticulum to the extracellular space without passage through the Golgi complex. J Biol Chem 2024; 300:107536. [PMID: 38971317 DOI: 10.1016/j.jbc.2024.107536] [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: 02/10/2024] [Revised: 05/29/2024] [Accepted: 06/21/2024] [Indexed: 07/08/2024] Open
Abstract
Protein disulfide isomerase-A1 (PDIA1) is a master regulator of oxidative protein folding and proteostasis in the endoplasmic reticulum (ER). However, PDIA1 can reach the extracellular space, impacting thrombosis and other pathophysiological phenomena. Whether PDIA1 is externalized via passive release or active secretion is not known. To investigate how PDIA1 negotiates its export, we generated a tagged variant that undergoes N-glycosylation in the ER (Glyco-PDIA1). Addition of N-glycans does not alter its enzymatic functions. Upon either deletion of its KDEL ER-localization motif or silencing of KDEL receptors, Glyco-PDIA1 acquires complex glycans in the Golgi and is secreted. In control cells, however, Glyco-PDIA1 is released with endoglycosidase-H sensitive glycans, implying that it does not follow the classical ER-Golgi route nor does it encounter glycanases in the cytosol. Extracellular Glyco-PDIA1 is more abundant than actin, lactate dehydrogenase, or other proteins released by damaged or dead cells, suggesting active transport through a Golgi-independent route. The strategy we describe herein can be extended to dissect how select ER-residents reach the extracellular space.
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Affiliation(s)
- Percillia Victoria Santos Oliveira
- Division of Genetics and Cell Biology Vita-Salute San Raffaele University and IRCCS San Raffaele Scientific Institute, Milan, Italy; Laboratorio de Biologia Vascular, LIM-64 (Biologia Cardiovascular Translacional), Instituto do Coração (InCor), Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brasil
| | - Marco Dalla Torre
- Division of Genetics and Cell Biology Vita-Salute San Raffaele University and IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Victor Debbas
- Laboratorio de Biologia Vascular, LIM-64 (Biologia Cardiovascular Translacional), Instituto do Coração (InCor), Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brasil
| | - Andrea Orsi
- Division of Genetics and Cell Biology Vita-Salute San Raffaele University and IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Francisco Rafael Martins Laurindo
- Laboratorio de Biologia Vascular, LIM-64 (Biologia Cardiovascular Translacional), Instituto do Coração (InCor), Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brasil.
| | - Roberto Sitia
- Division of Genetics and Cell Biology Vita-Salute San Raffaele University and IRCCS San Raffaele Scientific Institute, Milan, Italy.
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3
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Hasegawa H, Wang S, Kast E, Chou HT, Kaur M, Janlaor T, Mostafavi M, Wang YL, Li P. Understanding the biosynthesis of human IgM SAM-6 through a combinatorial expression of mutant subunits that affect product assembly and secretion. PLoS One 2024; 19:e0291568. [PMID: 38848420 PMCID: PMC11161108 DOI: 10.1371/journal.pone.0291568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Accepted: 05/06/2024] [Indexed: 06/09/2024] Open
Abstract
Polymeric IgMs are secreted from plasma cells abundantly despite their structural complexity and intricate multimerization steps. To gain insights into IgM's assembly mechanics that underwrite such high-level secretion, we characterized the biosynthetic process of a natural human IgM, SAM-6, using a heterologous HEK293(6E) cell platform that allowed the production of IgMs both in hexameric and pentameric forms in a controlled fashion. By creating a series of mutant subunits that differentially disrupt secretion, folding, and specific inter-chain disulfide bond formation, we assessed their effects on various aspects of IgM biosynthesis in 57 different subunit chain combinations, both in hexameric and pentameric formats. The mutations caused a spectrum of changes in steady-state subcellular subunit distribution, ER-associated inclusion body formation, intracellular subunit detergent solubility, covalent assembly, secreted IgM product quality, and secretion output. Some mutations produced differential effects on product quality depending on whether the mutation was introduced to hexameric IgM or pentameric IgM. Through this systematic combinatorial approach, we consolidate diverse overlapping knowledge on IgM biosynthesis for both hexamers and pentamers, while unexpectedly revealing that the loss of certain inter-chain disulfide bonds, including the one between μHC and λLC, is tolerated in polymeric IgM assembly and secretion. The findings highlight the differential roles of underlying non-covalent protein-protein interactions in hexamers and pentamers when orchestrating the initial subunit interactions and maintaining the polymeric IgM product integrity during ER quality control steps, secretory pathway trafficking, and secretion.
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Affiliation(s)
- Haruki Hasegawa
- Discovery Protein Science, Department of Large Molecule Discovery and Research Data Science, Amgen Inc., South San Francisco, CA, United States of America
| | - Songyu Wang
- Discovery Protein Science, Department of Large Molecule Discovery and Research Data Science, Amgen Inc., South San Francisco, CA, United States of America
| | - Eddie Kast
- Molecular Analytics, Department of Biologic Therapeutic Discovery, Amgen Inc., South San Francisco, CA, United States of America
| | - Hui-Ting Chou
- Structural Biology, Department of Small Molecule Therapeutic Discovery, Amgen Inc., South San Francisco, CA, United States of America
| | - Mehma Kaur
- Discovery Protein Science, Department of Large Molecule Discovery and Research Data Science, Amgen Inc., South San Francisco, CA, United States of America
| | - Tanakorn Janlaor
- Discovery Protein Science, Department of Large Molecule Discovery and Research Data Science, Amgen Inc., South San Francisco, CA, United States of America
| | - Mina Mostafavi
- Discovery Protein Science, Department of Large Molecule Discovery and Research Data Science, Amgen Inc., South San Francisco, CA, United States of America
| | - Yi-Ling Wang
- Discovery Protein Science, Department of Large Molecule Discovery and Research Data Science, Amgen Inc., South San Francisco, CA, United States of America
| | - Peng Li
- Discovery Protein Science, Department of Large Molecule Discovery and Research Data Science, Amgen Inc., South San Francisco, CA, United States of America
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Law ME, Dulloo ZM, Eggleston SR, Takacs GP, Alexandrow GM, Wang M, Su H, Forsyth B, Chiang CW, Sharma A, Kanumuri SRR, Guryanova OA, Harrison JK, Tirosh B, Castellano RK, Law BK. DR5 disulfide bonding as a sensor and effector of protein folding stress. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.04.583390. [PMID: 38496520 PMCID: PMC10942403 DOI: 10.1101/2024.03.04.583390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
New agents are needed that selectively kill cancer cells without harming normal tissues. The TRAIL ligand and its receptors, DR5 and DR4, exhibit cancer-selective toxicity, but TRAIL analogs or agonistic antibodies targeting these receptors have not received FDA approval for cancer therapy. Small molecules for activating DR5 or DR4 independently of protein ligands may bypass some of the pharmacological limitations of these protein drugs. Previously described Disulfide bond Disrupting Agents (DDAs) activate DR5 by altering its disulfide bonding through inhibition of the Protein Disulfide Isomerases (PDIs) ERp44, AGR2, and PDIA1. Work presented here extends these findings by showing that disruption of single DR5 disulfide bonds causes high-level DR5 expression, disulfide-mediated clustering, and activation of Caspase 8-Caspase 3 mediated pro-apoptotic signaling. Recognition of the extracellular domain of DR5 by various antibodies is strongly influenced by the pattern of DR5 disulfide bonding, which has important implications for the use of agonistic DR5 antibodies for cancer therapy. Disulfide-defective DR5 mutants do not activate the ER stress response or stimulate autophagy, indicating that these DDA-mediated responses are separable from DR5 activation and pro-apoptotic signaling. Importantly, other ER stressors, including Thapsigargin and Tunicamycin also alter DR5 disulfide bonding in various cancer cell lines and in some instances, DR5 mis-disulfide bonding is potentiated by overriding the Integrated Stress Response (ISR) with inhibitors of the PERK kinase or the ISR inhibitor ISRIB. These observations indicate that the pattern of DR5 disulfide bonding functions as a sensor of ER stress and serves as an effector of proteotoxic stress by driving extrinsic apoptosis independently of extracellular ligands.
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Muts RM, den Boer MA, Bardoel BW, Aerts PC, de Haas CJC, Heck AJR, Rooijakkers SHM, Heesterbeek DAC. Artificial surface labelling of Escherichia coli with StrepTagII antigen to study how monoclonal antibodies drive complement-mediated killing. Sci Rep 2023; 13:18836. [PMID: 37914798 PMCID: PMC10620216 DOI: 10.1038/s41598-023-46026-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 10/26/2023] [Indexed: 11/03/2023] Open
Abstract
Antibodies play a key role in the immune defence against Gram-negative bacteria. After binding to bacterial surface antigens, IgG and IgM can activate the complement system and trigger formation of lytic membrane attack complex (MAC) pores. Molecular studies to compare functional activity of antibodies on bacteria are hampered by the limited availability of well-defined antibodies against bacterial surface antigens. Therefore, we genetically engineered E. coli by expressing the StrepTagII antigen into outer membrane protein X (OmpX) and validated that these engineered bacteria were recognised by anti-StrepTagII antibodies. We then combined this antigen-antibody system with a purified complement assay to avoid interference of serum components and directly compare MAC-mediated bacterial killing via IgG1 and pentameric IgM. While both IgG1 and IgM could induce MAC-mediated killing, we show that IgM has an increased capacity to induce complement-mediated killing of E. coli compared to IgG1. While Fc mutations that enhance IgG clustering after target binding could not improve MAC formation, mutations that cause formation of pre-assembled IgG hexamers enhanced the complement activating capacity of IgG1. Altogether, we here present a system to study antibody-dependent complement activation on E. coli and show IgM's enhanced capacity over IgG to induce complement-mediated lysis of E. coli.
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Affiliation(s)
- Remy M Muts
- Department of Medical Microbiology, University Medical Center Utrecht, 3584 CX, Utrecht, The Netherlands
| | - Maurits A den Boer
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute of Pharmaceutical Sciences, Utrecht University, 3584 CH, Utrecht, The Netherlands
- Netherlands Proteomic Center, 3584 CH, Utrecht, The Netherlands
| | - Bart W Bardoel
- Department of Medical Microbiology, University Medical Center Utrecht, 3584 CX, Utrecht, The Netherlands
| | - Piet C Aerts
- Department of Medical Microbiology, University Medical Center Utrecht, 3584 CX, Utrecht, The Netherlands
| | - Carla J C de Haas
- Department of Medical Microbiology, University Medical Center Utrecht, 3584 CX, Utrecht, The Netherlands
| | - Albert J R Heck
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute of Pharmaceutical Sciences, Utrecht University, 3584 CH, Utrecht, The Netherlands
- Netherlands Proteomic Center, 3584 CH, Utrecht, The Netherlands
| | - Suzan H M Rooijakkers
- Department of Medical Microbiology, University Medical Center Utrecht, 3584 CX, Utrecht, The Netherlands
| | - Dani A C Heesterbeek
- Department of Medical Microbiology, University Medical Center Utrecht, 3584 CX, Utrecht, The Netherlands.
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6
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Wang S, Zhao Y, Mao S, Zhu J, Zhan Y, Cai D, Ma X, Wang D, Chen S. Enhancing the activity of disulfide-bond-containing proteins via promoting disulfide bond formation in Bacillus licheniformis. Int J Biol Macromol 2023; 233:123468. [PMID: 36731702 DOI: 10.1016/j.ijbiomac.2023.123468] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 01/24/2023] [Accepted: 01/25/2023] [Indexed: 02/01/2023]
Abstract
Disulfide bonds in proteins have strongly influence on the folding efficiency by constraining the conformational space. The inefficient disulfide bond formation of proteins is the main limiting factor of enzyme activity and stability. This study aimed to increase the activity of disulfide-bond-containing proteins via promoting disulfide bonds formation in Bacillus licheniformis. Initially, the glutamate decarboxylase GAD from Escherichia coli was selected as the model protein and introduced into the B. licheniformis. Then, the disulfide isomerase and oxidoreductase from different sources were excavated and overexpressed successively to improve the catalytic efficiency of GAD. The final engineered B. licheniformis showed significantly improved GAD specific activity (from 10.4 U/mg to 80.0 U/mg), which also presented perfect adaptability for other disulfide-bond-containing proteins, for instance, UDP-glucosyltransferase from Arabidopsis thaliana. Taken together, our work demonstrated that the activity of GAD in B. licheniformis was regulated by the disulfide bonds formation status and provided a promising platform for the expression of disulfide-bond-containing proteins.
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Affiliation(s)
- Shiyi Wang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, Wuhan 430062, PR China
| | - Yiwen Zhao
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, Wuhan 430062, PR China
| | - Shufen Mao
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, Wuhan 430062, PR China
| | - Jiang Zhu
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, Wuhan 430062, PR China
| | - Yangyang Zhan
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, Wuhan 430062, PR China
| | - Dongbo Cai
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, Wuhan 430062, PR China
| | - Xin Ma
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, Wuhan 430062, PR China
| | - Dong Wang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, Wuhan 430062, PR China.
| | - Shouwen Chen
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, Wuhan 430062, PR China.
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7
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Wang L, Wang CC. Oxidative protein folding fidelity and redoxtasis in the endoplasmic reticulum. Trends Biochem Sci 2023; 48:40-52. [PMID: 35871147 DOI: 10.1016/j.tibs.2022.06.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2022] [Revised: 06/16/2022] [Accepted: 06/29/2022] [Indexed: 02/09/2023]
Abstract
In eukaryotic cells, oxidative protein folding occurs in the lumen of the endoplasmic reticulum (ER), catalyzed by ER sulfhydryl oxidase 1 (Ero1) and protein disulfide isomerase (PDI). The efficiency and fidelity of oxidative protein folding are vital for the function of secretory cells. Here, we summarize oxidative protein folding in yeast, plants, and mammals, and discuss how the conformation and activity of human Ero1-PDI machinery is regulated through various post-translational modifications (PTMs). We propose that oxidative protein folding fidelity and ER redox homeostasis are maintained by both the precise control of Ero1 oxidase activity and the division of labor between PDI family members. We also discuss how deregulated Ero1-PDI functions contribute to human diseases and can be leveraged for therapeutic interventions.
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Affiliation(s)
- Lei Wang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Chih-Chen Wang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
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8
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Chen Q, Menon R, Calder LJ, Tolar P, Rosenthal PB. Cryomicroscopy reveals the structural basis for a flexible hinge motion in the immunoglobulin M pentamer. Nat Commun 2022; 13:6314. [PMID: 36274064 PMCID: PMC9588798 DOI: 10.1038/s41467-022-34090-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 10/12/2022] [Indexed: 12/25/2022] Open
Abstract
Immunoglobulin M (IgM) is the most ancient of the five isotypes of immunoglobulin (Ig) molecules and serves as the first line of defence against pathogens. Here, we use cryo-EM to image the structure of the human full-length IgM pentamer, revealing antigen binding domains flexibly attached to the asymmetric and rigid core formed by the Cμ4 and Cμ3 constant regions and the J-chain. A hinge is located at the Cμ3/Cμ2 domain interface, allowing Fabs and Cμ2 to pivot as a unit both in-plane and out-of-plane. This motion is different from that observed in IgG and IgA, where the two Fab arms are able to swing independently. A biased orientation of one pair of Fab arms results from asymmetry in the constant domain (Cμ3) at the IgM subunit interacting most extensively with the J-chain. This may influence the multi-valent binding to surface-associated antigens and complement pathway activation. By comparison, the structure of the Fc fragment in the IgM monomer is similar to that of the pentamer, but is more dynamic in the Cμ4 domain.
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Affiliation(s)
- Qu Chen
- grid.451388.30000 0004 1795 1830Structural Biology Science Technology Platform, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT UK
| | - Rajesh Menon
- grid.451388.30000 0004 1795 1830Immune Receptor Activation Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT UK
| | - Lesley J. Calder
- grid.451388.30000 0004 1795 1830Structural Biology of Cells and Viruses Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT UK
| | - Pavel Tolar
- Immune Receptor Activation Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK. .,Institute of Immunity and Transplantation, University College London, Rowland Hill Street, London, NW3 2PP, UK.
| | - Peter B. Rosenthal
- grid.451388.30000 0004 1795 1830Structural Biology of Cells and Viruses Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT UK
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Sorrentino I, Galli M, Medraño-Fernandez I, Sitia R. Transfer of H 2O 2 from Mitochondria to the endoplasmic reticulum via Aquaporin-11. Redox Biol 2022; 55:102410. [PMID: 35863264 PMCID: PMC9304643 DOI: 10.1016/j.redox.2022.102410] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 07/12/2022] [Accepted: 07/12/2022] [Indexed: 01/20/2023] Open
Abstract
Some aquaporins (AQPs) can transport H2O2 across membranes, allowing redox signals to proceed in and between cells. Unlike other peroxiporins, human AQP11 is an endoplasmic reticulum (ER)-resident that can conduit H2O2 to the cytosol. Here, we show that silencing Ero1α, an ER flavoenzyme that generates abundant H2O2 during oxidative folding, causes a paradoxical increase in luminal H2O2 levels. The simultaneous AQP11 downregulation prevents this increase, implying that H2O2 reaches the ER from an external source(s). Pharmacological inhibition of the electron transport chain reveals that Ero1α downregulation activates superoxide production by complex III. In the intermembrane space, superoxide dismutase 1 generates H2O2 that enters the ER channeled by AQP11. Meanwhile, the number of ER-mitochondria contact sites increases as well, irrespective of AQP11 expression. Taken together, our findings identify a novel interorganellar redox response that is activated upon Ero1α downregulation and transfers H2O2 from mitochondria to the ER via AQP11.
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Affiliation(s)
- Ilaria Sorrentino
- Division of Genetics and Cell Biology, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Ospedale San Raffaele, Università Vita-Salute San Raffaele, 20132, Milan, Italy
| | - Mauro Galli
- Department of Medical Biology, Medical University of Białystok, 15222, Białystok, Poland
| | - Iria Medraño-Fernandez
- Department of Bioengineering and Aerospace Engineering, University Carlos III of Madrid, 28911, Madrid, Spain.
| | - Roberto Sitia
- Division of Genetics and Cell Biology, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Ospedale San Raffaele, Università Vita-Salute San Raffaele, 20132, Milan, Italy.
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10
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Palazzo FC, Sitia R, Tempio T. Selective Secretion of KDEL-Bearing Proteins: Mechanisms and Functions. Front Cell Dev Biol 2022; 10:967875. [PMID: 35912099 PMCID: PMC9326092 DOI: 10.3389/fcell.2022.967875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 06/24/2022] [Indexed: 11/13/2022] Open
Abstract
In multicellular organisms, cells must continuously exchange messages with the right meaning, intensity, and duration. Most of these messages are delivered through cognate interactions between membrane and secretory proteins. Their conformational maturation is assisted by a vast array of chaperones and enzymes, ensuring the fidelity of intercellular communication. These folding assistants reside in the early secretory compartment (ESC), a functional unit that encompasses endoplasmic reticulum (ER), intermediate compartment and cis-Golgi. Most soluble ESC residents have C-terminal KDEL-like motifs that prevent their transport beyond the Golgi. However, some accumulate in the ER, while others in downstream stations, implying different recycling rates. Moreover, it is now clear that cells can actively secrete certain ESC residents but not others. This essay discusses the physiology of their differential intracellular distribution, and the mechanisms that may ensure selectivity of release.
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11
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Liu P, Wang X, Sun Y, Zhao H, Cheng F, Wang J, Yang F, Hu J, Zhang H, Wang CC, Wang L. SARS-CoV-2 ORF8 reshapes the ER through forming mixed disulfides with ER oxidoreductases. Redox Biol 2022; 54:102388. [PMID: 35792438 PMCID: PMC9239706 DOI: 10.1016/j.redox.2022.102388] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 06/18/2022] [Accepted: 06/26/2022] [Indexed: 01/22/2023] Open
Abstract
The replication machinery of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is closely associated with the endoplasmic reticulum (ER) in host cells. Activation of the unfolded protein response (UPR) is a strategy hijacked by coronavirus to facilitate its replication and suppress host innate immunity. Here, we have found that SARS-CoV-2 ORF8 protein accumulates in the ER and escapes the degradation system by forming mixed disulfide complexes with ER oxidoreductases. ORF8 induces the activation of three UPR pathways through targeting key UPR components, remodels ER morphology and accelerates protein trafficking. Moreover, small molecule reducing agents release ORF8 from the mixed disulfide complexes and facilitate its degradation, therefore mitigate ER stress. Our study reveals a unique mechanism by which SARS-CoV-2 ORF8 escapes degradation by host cells and regulates ER reshaping. Targeting ORF8-involved mixed disulfide complexes could be a new strategy to alleviate SARS-CoV-2 induced ER stress and related diseases. SARS-CoV-2 ORF8 protein accumulates in the ER through forming mixed disulfide complexes. Two key protein disulfide isomerases, PDI and ERp44, are main targets of ORF8. ORF8 induces ER stress, remodels the ER and accelerates protein trafficking. Small molecule reducing agents facilitates the degradation of ORF8 and mitigates ER stress.
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Affiliation(s)
- Ping Liu
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Xi Wang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.
| | - Yiwei Sun
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Hongyu Zhao
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Fang Cheng
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jifeng Wang
- Laboratory of Proteomics, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Fuquan Yang
- Laboratory of Proteomics, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Junjie Hu
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Hong Zhang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Chih-Chen Wang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Lei Wang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China.
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Brücksken KA, Loreto Palacio P, Hanschmann EM. Thiol Modifications in the Extracellular Space—Key Proteins in Inflammation and Viral Infection. Front Immunol 2022; 13:932525. [PMID: 35833136 PMCID: PMC9271835 DOI: 10.3389/fimmu.2022.932525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 05/23/2022] [Indexed: 11/13/2022] Open
Abstract
Posttranslational modifications (PTMs) allow to control molecular and cellular functions in response to specific signals and changes in the microenvironment of cells. They regulate structure, localization, stability, and function of proteins in a spatial and temporal manner. Among them, specific thiol modifications of cysteine (Cys) residues facilitate rapid signal transduction. In fact, Cys is unique because it contains the highly reactive thiol group that can undergo different reversible and irreversible modifications. Upon inflammation and changes in the cellular microenvironment, many extracellular soluble and membrane proteins undergo thiol modifications, particularly dithiol–disulfide exchange, S-glutathionylation, and S-nitrosylation. Among others, these thiol switches are essential for inflammatory signaling, regulation of gene expression, cytokine release, immunoglobulin function and isoform variation, and antigen presentation. Interestingly, also the redox state of bacterial and viral proteins depends on host cell-mediated redox reactions that are critical for invasion and infection. Here, we highlight mechanistic thiol switches in inflammatory pathways and infections including cholera, diphtheria, hepatitis, human immunodeficiency virus (HIV), influenza, and coronavirus disease 2019 (COVID-19).
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