1
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Yang K, Feng Z, Pastor-Pareja JC. p24-Tango1 interactions ensure ER-Golgi interface stability and efficient transport. J Cell Biol 2024; 223:e202309045. [PMID: 38470362 PMCID: PMC10932740 DOI: 10.1083/jcb.202309045] [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: 09/07/2023] [Revised: 01/07/2024] [Accepted: 02/05/2024] [Indexed: 03/13/2024] Open
Abstract
The eukaryotic p24 family, consisting of α-, β-, γ- and δ-p24 subfamilies, has long been known to be involved in regulating secretion. Despite increasing interest in these proteins, fundamental questions remain about their role. Here, we systematically investigated Drosophila p24 proteins. We discovered that members of all four p24 subfamilies are required for general secretion and that their localizations between ER exit site (ERES) and Golgi are interdependent in an α→βδ→γ sequence. We also found that localization of p24 proteins and ERES determinant Tango1 requires interaction through their respective GOLD and SH3 lumenal domains, with Tango1 loss sending p24 proteins to the plasma membrane and vice versa. Finally, we show that p24 loss expands the COPII zone at ERES and increases the number of ER-Golgi vesicles, supporting a restrictive role of p24 proteins on vesicle budding for efficient transport. Our results reveal Tango1-p24 interplay as central to the generation of a stable ER-Golgi interface.
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Affiliation(s)
- Ke Yang
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Zhi Feng
- School of Life Sciences, Tsinghua University, Beijing, China
| | - José Carlos Pastor-Pareja
- School of Life Sciences, Tsinghua University, Beijing, China
- Tsinghua-Peking Center for Life Sciences, Beijing, China
- Institute of Neurosciences, Consejo Superior de Investigaciones Científicas-Universidad Miguel Hernández, San Juan de Alicante, Spain
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2
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Piccolo D, Zarouchlioti C, Bellingham J, Guarascio R, Ziaka K, Molday RS, Cheetham ME. A Proximity Complementation Assay to Identify Small Molecules That Enhance the Traffic of ABCA4 Misfolding Variants. Int J Mol Sci 2024; 25:4521. [PMID: 38674104 PMCID: PMC11050442 DOI: 10.3390/ijms25084521] [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: 02/29/2024] [Revised: 04/16/2024] [Accepted: 04/18/2024] [Indexed: 04/28/2024] Open
Abstract
ABCA4-related retinopathy is the most common inherited Mendelian eye disorder worldwide, caused by biallelic variants in the ATP-binding cassette transporter ABCA4. To date, over 2200 ABCA4 variants have been identified, including missense, nonsense, indels, splice site and deep intronic defects. Notably, more than 60% are missense variants that can lead to protein misfolding, mistrafficking and degradation. Currently no approved therapies target ABCA4. In this study, we demonstrate that ABCA4 misfolding variants are temperature-sensitive and reduced temperature growth (30 °C) improves their traffic to the plasma membrane, suggesting the folding of these variants could be rescuable. Consequently, an in vitro platform was developed for the rapid and robust detection of ABCA4 traffic to the plasma membrane in transiently transfected cells. The system was used to assess selected candidate small molecules that were reported to improve the folding or traffic of other ABC transporters. Two candidates, 4-PBA and AICAR, were identified and validated for their ability to enhance both wild-type ABCA4 and variant trafficking to the cell surface in cell culture. We envision that this platform could serve as a primary screen for more sophisticated in vitro testing, enabling the discovery of breakthrough agents to rescue ABCA4 protein defects and mitigate ABCA4-related retinopathy.
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Affiliation(s)
- Davide Piccolo
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK; (D.P.); (C.Z.); (R.G.); (K.Z.)
| | - Christina Zarouchlioti
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK; (D.P.); (C.Z.); (R.G.); (K.Z.)
| | - James Bellingham
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK; (D.P.); (C.Z.); (R.G.); (K.Z.)
| | - Rosellina Guarascio
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK; (D.P.); (C.Z.); (R.G.); (K.Z.)
| | - Kalliopi Ziaka
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK; (D.P.); (C.Z.); (R.G.); (K.Z.)
| | - Robert S. Molday
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC V6T 1Z3, Canada;
| | - Michael E. Cheetham
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK; (D.P.); (C.Z.); (R.G.); (K.Z.)
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3
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Pearson GJ, Mears HV, Broncel M, Snijders AP, Bauer DLV, Carlton JG. ER-export and ARFRP1/AP-1-dependent delivery of SARS-CoV-2 Envelope to lysosomes controls late stages of viral replication. SCIENCE ADVANCES 2024; 10:eadl5012. [PMID: 38569033 PMCID: PMC10990277 DOI: 10.1126/sciadv.adl5012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Accepted: 02/28/2024] [Indexed: 04/05/2024]
Abstract
The β-coronavirus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of the global COVID-19 pandemic. Coronaviral Envelope (E) proteins are pentameric viroporins that play essential roles in assembly, release, and pathogenesis. We developed a nondisruptive tagging strategy for SARS-CoV-2 E and find that, at steady state, it localizes to the Golgi and to lysosomes. We identify sequences in E, conserved across Coronaviridae, responsible for endoplasmic reticulum-to-Golgi export, and relate this activity to interaction with COP-II via SEC24. Using proximity biotinylation, we identify an ADP ribosylation factor 1/adaptor protein-1 (ARFRP1/AP-1)-dependent pathway allowing Golgi-to-lysosome trafficking of E. We identify sequences in E that bind AP-1, are conserved across β-coronaviruses, and allow E to be trafficked from Golgi to lysosomes. We show that E acts to deacidify lysosomes and, by developing a trans-complementation assay for SARS-CoV-2 structural proteins, that lysosomal delivery of E and its viroporin activity is necessary for efficient viral replication and release.
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Affiliation(s)
- Guy J. Pearson
- Organelle Dynamics Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
- School of Cancer & Pharmaceutical Sciences, King’s College London, Great Maze Pond, London SE1 1UL, UK
| | - Harriet V. Mears
- RNA Virus Replication Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Malgorzata Broncel
- Proteomic Science Technology Platform, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Ambrosius P. Snijders
- Proteomic Science Technology Platform, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - David L. V. Bauer
- RNA Virus Replication Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Jeremy G. Carlton
- Organelle Dynamics Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
- School of Cancer & Pharmaceutical Sciences, King’s College London, Great Maze Pond, London SE1 1UL, UK
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4
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Robinson CM, Duggan A, Forrester A. ER exit in physiology and disease. Front Mol Biosci 2024; 11:1352970. [PMID: 38314136 PMCID: PMC10835805 DOI: 10.3389/fmolb.2024.1352970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2023] [Accepted: 01/05/2024] [Indexed: 02/06/2024] Open
Abstract
The biosynthetic secretory pathway is comprised of multiple steps, modifications and interactions that form a highly precise pathway of protein trafficking and secretion, that is essential for eukaryotic life. The general outline of this pathway is understood, however the specific mechanisms are still unclear. In the last 15 years there have been vast advancements in technology that enable us to advance our understanding of this complex and subtle pathway. Therefore, based on the strong foundation of work performed over the last 40 years, we can now build another level of understanding, using the new technologies available. The biosynthetic secretory pathway is a high precision process, that involves a number of tightly regulated steps: Protein folding and quality control, cargo selection for Endoplasmic Reticulum (ER) exit, Golgi trafficking, sorting and secretion. When deregulated it causes severe diseases that here we categorise into three main groups of aberrant secretion: decreased, excess and altered secretion. Each of these categories disrupts organ homeostasis differently, effecting extracellular matrix composition, changing signalling events, or damaging the secretory cells due to aberrant intracellular accumulation of secretory proteins. Diseases of aberrant secretion are very common, but despite this, there are few effective therapies. Here we describe ER exit sites (ERES) as key hubs for regulation of the secretory pathway, protein quality control and an integratory hub for signalling within the cell. This review also describes the challenges that will be faced in developing effective therapies, due to the specificity required of potential drug candidates and the crucial need to respect the fine equilibrium of the pathway. The development of novel tools is moving forward, and we can also use these tools to build our understanding of the acute regulation of ERES and protein trafficking. Here we review ERES regulation in context as a therapeutic strategy.
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Affiliation(s)
- Claire M Robinson
- School of Medicine, Health Sciences Centre, University College Dublin, Dublin, Ireland
- Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin, Ireland
| | - Aislinn Duggan
- School of Medicine, Health Sciences Centre, University College Dublin, Dublin, Ireland
- Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin, Ireland
| | - Alison Forrester
- Research Unit of Cell Biology (URBC), Namur Research Institute for Life Sciences (NARILIS), University of Namur, Namur, Belgium
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5
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Bunel L, Pincet L, Malhotra V, Raote I, Pincet F. A model for collagen secretion by intercompartmental continuities. Proc Natl Acad Sci U S A 2024; 121:e2310404120. [PMID: 38147551 PMCID: PMC10769856 DOI: 10.1073/pnas.2310404120] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 11/14/2023] [Indexed: 12/28/2023] Open
Abstract
Newly synthesized secretory proteins are exported from the endoplasmic reticulum (ER) at specialized subcompartments called exit sites (ERES). Cargoes like procollagen are too large for export by the standard COPII-coated vesicle of 60 nm average diameter. We have previously suggested that procollagen is transported from the ER to the next secretory organelle, the ER-Golgi intermediate compartment (ERGIC), in TANGO1-dependent interorganelle tunnels. In the theoretical model presented here, we suggest that intrinsically disordered domains of TANGO1 in the ER lumen induce an entropic contraction, which exerts a force that draws procollagen toward the ERES. Within this framework, molecular gradients of pH and/or HSP47 between the ER and ERGIC create a force in the order of tens of femto-Newtons. This force is substantial enough to propel procollagen from the ER at a speed of approximately 1 nm · s-1. This calculated speed and the quantities of collagen secreted are similar to its observed physiological secretion rate in fibroblasts, consistent with the proposal that ER export is the rate-limiting step for procollagen secretion. Hence, the mechanism we propose is theoretically adequate to explain how cells can utilize molecular gradients and export procollagens at a rate commensurate with physiological needs.
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Affiliation(s)
- Louis Bunel
- Laboratoire de Physique de l’École normale supérieure, École Normale Supérieure, Université Paris Sciences et Lettres, CNRS, Sorbonne Université, Université Paris Cité, F-75005Paris, France
| | - Lancelot Pincet
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d’Orsay, 91405Orsay, France
| | - Vivek Malhotra
- Centre for Genomic Regulation, The Barcelona Institute of Science and Technology, Barcelona08003, Spain
- Universitat Pompeu Fabra, Barcelona08003, Spain
- Institució Catalana de Recerca i Estudis Avançats, Barcelona08010, Spain
| | - Ishier Raote
- Université Paris Cité, CNRS, Institut Jacques Monod, F-75013Paris, France
| | - Frédéric Pincet
- Laboratoire de Physique de l’École normale supérieure, École Normale Supérieure, Université Paris Sciences et Lettres, CNRS, Sorbonne Université, Université Paris Cité, F-75005Paris, France
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6
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Held A, Lapka J, Sargeant J, Hojanazarova J, Shaheen A, Galindo S, Madreiter-Sokolowski C, Malli R, Graier WF, Hay JC. Steady-state regulation of COPII-dependent secretory cargo sorting by inositol trisphosphate receptors, calcium, and penta EF hand proteins. J Biol Chem 2023; 299:105471. [PMID: 37979918 PMCID: PMC10750190 DOI: 10.1016/j.jbc.2023.105471] [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: 07/01/2023] [Revised: 10/30/2023] [Accepted: 11/02/2023] [Indexed: 11/20/2023] Open
Abstract
Recently, we demonstrated that agonist-stimulated Ca2+ signaling involving IP3 receptors modulates ER export rates through activation of the penta-EF Hand proteins apoptosis-linked gene-2 (ALG-2) and peflin. It is unknown, however, whether IP3Rs and penta-EF proteins regulate ER export rates at steady state. Here we tested this idea in normal rat kidney epithelial cells by manipulation of IP3R isoform expression. Under standard growth conditions, spontaneous cytosolic Ca2+ oscillations occurred simultaneously in successive groups of contiguous cells, generating intercellular Ca2+ waves that moved across the monolayer periodically. Depletion of IP3R-3, typically the least promiscuous IP3R isoform, caused increased cell participation in intercellular Ca2+ waves in unstimulated cells. The increased spontaneous signaling was sufficient to cause increased ALG-2 and COPII coat subunit Sec31A and decreased peflin localization at ER exit sites, resulting in increased ER-to-Golgi transport of the COPII client cargo VSV-G. The elevated ER-to-Golgi transport caused greater concentration of VSV-G at ER exit sites and had reciprocal effects on transport of VSV-G and a bulk-flow cargo, though both cargos equally required Sec31A. Inactivation of client cargo sorting using 4-phenylbutyrate had opposing reciprocal effects on client and bulk-flow cargo and neutralized any effect of ALG-2 activation on transport. This work extends our knowledge of ALG-2 mechanisms and indicates that in normal rat kidney cells, IP3R isoforms regulate homeostatic Ca2+ signaling that helps determine the basal secretion rate and stringency of COPII-dependent cargo sorting.
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Affiliation(s)
- Aaron Held
- Division of Biological Sciences, Center for Structural & Functional Neuroscience, University of Montana, Missoula, Montana, USA
| | - Jacob Lapka
- Division of Biological Sciences, Center for Structural & Functional Neuroscience, University of Montana, Missoula, Montana, USA
| | - John Sargeant
- Division of Biological Sciences, Center for Structural & Functional Neuroscience, University of Montana, Missoula, Montana, USA
| | - Jennet Hojanazarova
- Division of Biological Sciences, Center for Structural & Functional Neuroscience, University of Montana, Missoula, Montana, USA
| | - Alaa Shaheen
- Division of Biological Sciences, Center for Structural & Functional Neuroscience, University of Montana, Missoula, Montana, USA
| | - Samuel Galindo
- Division of Biological Sciences, Center for Structural & Functional Neuroscience, University of Montana, Missoula, Montana, USA
| | - Corina Madreiter-Sokolowski
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Graz, Austria
| | - Roland Malli
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Graz, Austria
| | - Wolfgang F Graier
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Graz, Austria
| | - Jesse C Hay
- Division of Biological Sciences, Center for Structural & Functional Neuroscience, University of Montana, Missoula, Montana, USA.
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7
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Morales-Paytuví F, Fajardo A, Ruiz-Mirapeix C, Rae J, Tebar F, Bosch M, Enrich C, Collins BM, Parton RG, Pol A. Early proteostasis of caveolins synchronizes trafficking, degradation, and oligomerization to prevent toxic aggregation. J Cell Biol 2023; 222:e202204020. [PMID: 37526691 PMCID: PMC10394380 DOI: 10.1083/jcb.202204020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 04/05/2023] [Accepted: 06/09/2023] [Indexed: 08/02/2023] Open
Abstract
Caveolin-1 (CAV1) and CAV3 are membrane-sculpting proteins driving the formation of the plasma membrane (PM) caveolae. Within the PM mosaic environment, caveola assembly is unique as it requires progressive oligomerization of newly synthesized caveolins while trafficking through the biosynthetic-secretory pathway. Here, we have investigated these early events by combining structural, biochemical, and microscopy studies. We uncover striking trafficking differences between caveolins, with CAV1 rapidly exported to the Golgi and PM while CAV3 is initially retained in the endoplasmic reticulum and laterally moves into lipid droplets. The levels of caveolins in the endoplasmic reticulum are controlled by proteasomal degradation, and only monomeric/low oligomeric caveolins are exported into the cis-Golgi with higher-order oligomers assembling beyond this compartment. When any of those early proteostatic mechanisms are compromised, chemically or genetically, caveolins tend to accumulate along the secretory pathway forming non-functional aggregates, causing organelle damage and triggering cellular stress. Accordingly, we propose a model in which disrupted proteostasis of newly synthesized caveolins contributes to pathogenesis.
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Affiliation(s)
- Frederic Morales-Paytuví
- Lipid Trafficking and Disease Group, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Alba Fajardo
- Lipid Trafficking and Disease Group, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Carles Ruiz-Mirapeix
- Lipid Trafficking and Disease Group, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - James Rae
- Institute for Molecular Bioscience (IMB), The University of Queensland (UQ) , Brisbane, Australia
| | - Francesc Tebar
- Department of Biomedical Sciences, Faculty of Medicine, Universitat de Barcelona, Barcelona, Spain
| | - Marta Bosch
- Lipid Trafficking and Disease Group, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
- Department of Biomedical Sciences, Faculty of Medicine, Universitat de Barcelona, Barcelona, Spain
| | - Carlos Enrich
- Department of Biomedical Sciences, Faculty of Medicine, Universitat de Barcelona, Barcelona, Spain
| | - Brett M Collins
- Institute for Molecular Bioscience (IMB), The University of Queensland (UQ) , Brisbane, Australia
| | - Robert G Parton
- Institute for Molecular Bioscience (IMB), The University of Queensland (UQ) , Brisbane, Australia
- Centre for Microscopy and Microanalysis (CMM), The University of Queensland (UQ), Brisbane, Australia
| | - Albert Pol
- Lipid Trafficking and Disease Group, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
- Department of Biomedical Sciences, Faculty of Medicine, Universitat de Barcelona, Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA) , Barcelona, Spain
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8
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Patel S, Bhatt AM, Bhansali P, Setty SRG. Pseudophosphatase STYXL1 depletion enhances glucocerebrosidase trafficking to lysosomes via ER stress. Traffic 2023; 24:254-269. [PMID: 37198709 DOI: 10.1111/tra.12886] [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: 12/07/2022] [Revised: 03/28/2023] [Accepted: 03/29/2023] [Indexed: 05/19/2023]
Abstract
Pseudophosphatases are catalytically inactive but share sequence and structural similarities with classical phosphatases. STYXL1 is a pseudophosphatase that belongs to the family of dual-specificity phosphatases and is known to regulate stress granule formation, neurite formation and apoptosis in different cell types. However, the role of STYXL1 in regulating cellular trafficking or the lysosome function has not been elucidated. Here, we show that the knockdown of STYXL1 enhances the trafficking of β-glucocerebrosidase (β-GC) and its lysosomal activity in HeLa cells. Importantly, the STYXL1-depleted cells display enhanced distribution of endoplasmic reticulum (ER), late endosome and lysosome compartments. Further, knockdown of STYXL1 causes the nuclear translocation of unfolded protein response (UPR) and lysosomal biogenesis transcription factors. However, the upregulated β-GC activity in the lysosomes is independent of TFEB/TFE3 nuclear localization in STYXL1 knockdown cells. The treatment of STYXL1 knockdown cells with 4-PBA (ER stress attenuator) significantly reduces the β-GC activity equivalent to control cells but not additive with thapsigargin, an ER stress activator. Additionally, STYXL1-depleted cells show the enhanced contact of lysosomes with ER, possibly via increased UPR. The depletion of STYXL1 in human primary fibroblasts derived from Gaucher patients showed moderately enhanced lysosomal enzyme activity. Overall, these studies illustrated the unique role of pseudophosphatase STYXL1 in modulating the lysosome function both in normal and lysosome-storage disorder cell types. Thus, designing small molecules against STYXL1 possibly can restore the lysosome activity by enhancing ER stress in Gaucher disease.
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Affiliation(s)
- Saloni Patel
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
| | - Anshul Milap Bhatt
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
| | - Priyanka Bhansali
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
| | - Subba Rao Gangi Setty
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
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9
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Elverson K, Warwicker J, Freeman S, Manson F. Tadalafil Rescues the p.M325T Mutant of Best1 Chloride Channel. Molecules 2023; 28:molecules28083317. [PMID: 37110551 PMCID: PMC10142963 DOI: 10.3390/molecules28083317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 03/24/2023] [Accepted: 03/31/2023] [Indexed: 04/29/2023] Open
Abstract
Bestrophin 1 (Best1) is a chloride channel that localises to the plasma membrane of retinal pigment epithelium (RPE) cells. Mutations in the BEST1 gene are associated with a group of untreatable inherited retinal dystrophies (IRDs) called bestrophinopathies, caused by protein instability and loss-of-function of the Best1 protein. 4PBA and 2-NOAA have been shown to rescue the function, expression, and localisation of Best1 mutants; however, it is of interest to find more potent analogues as the concentration of the drugs required is too high (2.5 mM) to be given therapeutically. A virtual docking model of the COPII Sec24a site, where 4PBA has been shown to bind, was generated and a library of 1416 FDA-approved compounds was screened at the site. The top binding compounds were tested in vitro in whole-cell patch-clamp experiments of HEK293T cells expressing mutant Best1. The application of 25 μM tadalafil resulted in full rescue of Cl- conductance, comparable to wild type Best1 levels, for p.M325T mutant Best1 but not for p.R141H or p.L234V mutants.
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Affiliation(s)
- Kathleen Elverson
- Division of Evolution, Infection and Genomics, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PT, UK
| | - Jim Warwicker
- Division of Molecular and Cellular Function, Faculty of Biology, Medicine and Health, Manchester Institute of Biotechnology, The University of Manchester, Manchester M1 7DN, UK
| | - Sally Freeman
- Division of Pharmacy and Optometry, School of Health Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PT, UK
| | - Forbes Manson
- Division of Evolution, Infection and Genomics, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PT, UK
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10
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Van der Verren SE, Zanetti G. The small GTPase Sar1, control centre of COPII trafficking. FEBS Lett 2023; 597:865-882. [PMID: 36737236 DOI: 10.1002/1873-3468.14595] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 01/23/2023] [Accepted: 01/25/2023] [Indexed: 02/05/2023]
Abstract
Sar1 is a small GTPase of the ARF family. Upon exchange of GDP for GTP, Sar1 associates with the endoplasmic reticulum (ER) membrane and recruits COPII components, orchestrating cargo concentration and membrane deformation. Many aspects of the role of Sar1 and regulation of its GTP cycle remain unclear, especially as complexity increases in higher organisms that secrete a wider range of cargoes. This review focusses on the regulation of GTP hydrolysis and its role in coat assembly, as well as the mechanism of Sar1-induced membrane deformation and scission. Finally, we highlight the additional specialisation in higher eukaryotes and the outstanding questions on how Sar1 functions are orchestrated.
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Affiliation(s)
| | - Giulia Zanetti
- Institute of Structural and Molecular Biology, Birkbeck College London, UK
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11
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Roberts BS, Satpute-Krishnan P. The many hats of transmembrane emp24 domain protein TMED9 in secretory pathway homeostasis. Front Cell Dev Biol 2023; 10:1096899. [PMID: 36733337 PMCID: PMC9888432 DOI: 10.3389/fcell.2022.1096899] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2022] [Accepted: 12/29/2022] [Indexed: 01/18/2023] Open
Abstract
The secretory pathway is an intracellular highway for the vesicular transport of newly synthesized proteins that spans the endoplasmic reticulum (ER), Golgi, lysosomes and the cell surface. A variety of cargo receptors, chaperones, and quality control proteins maintain the smooth flow of cargo along this route. Among these is vesicular transport protein TMED9, which belongs to the p24/transmembrane emp24 domain (TMED) family of proteins, and is expressed across vertebrate species. The TMED family is comprised of structurally-related type I transmembrane proteins with a luminal N-terminal Golgi-dynamics domain, a luminal coiled-coil domain, a transmembrane domain and a short cytosolic C-terminal tail that binds COPI and COPII coat proteins. TMED9, like other members of the TMED family, was first identified as an abundant constituent of the COPI and COPII coated vesicles that mediate traffic between the ER and the Golgi. TMED9 is typically purified in hetero-oligomers together with TMED family members, suggesting that it may function as part of a complex. Recently, TMED family members have been discovered to play various roles in secretory pathway homeostasis including secreted protein processing, quality control and degradation of misfolded proteins, and post-Golgi trafficking. In particular, TMED9 has been implicated in autophagy, lysosomal sorting, viral replication and cancer, which we will discuss in this Mini-Review.
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12
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Stein D, Slobodnik Z, Tam B, Einav M, Akabayov B, Berstein S, Toiber D. 4-phenylbutyric acid-Identity crisis; can it act as a translation inhibitor? Aging Cell 2022; 21:e13738. [PMID: 36373957 PMCID: PMC9741500 DOI: 10.1111/acel.13738] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 09/30/2022] [Accepted: 10/21/2022] [Indexed: 11/16/2022] Open
Abstract
Loss of proteostasis can occur due to mutations, the formation of aggregates, or general deficiency in the correct translation and folding of proteins. These phenomena are commonly observed in pathologies, but most significantly, loss of proteostasis characterizes aging. This loss leads to the chronic activation of stress responses and has a generally deleterious impact on the organism. While finding molecules that can alleviate these symptoms is an important step toward solutions for these conditions, some molecules might be mischaracterized on the way. 4-phenylbutyric acid (4PBA) is known for its role as a chemical chaperone that helps alleviate endoplasmic reticulum (ER) stress, yet a scan of the literature reveals that no biochemical or molecular experiments have shown any protein refolding capacity. Here, we show that 4PBA is a conserved weak inhibitor of mRNA translation, both in vitro and in cellular systems, and furthermore-it does not promote protein folding nor prevents aggregation. 4PBA possibly alleviates proteostatic or ER stress by inhibiting protein synthesis, allowing the cells to cope with misfolded proteins by reducing the protein load. Better understanding of 4PBA biochemical mechanisms will improve its usage in basic science and as a drug in different pathologies, also opening new venues for the treatment of different diseases.
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Affiliation(s)
- Daniel Stein
- Department of Life SciencesBen‐Gurion University of the NegevBeer ShevaIsrael,The Zlotowski Center for NeuroscienceBen‐Gurion University of the NegevBeer ShevaIsrael
| | - Zeev Slobodnik
- Department of Life SciencesBen‐Gurion University of the NegevBeer ShevaIsrael,The Zlotowski Center for NeuroscienceBen‐Gurion University of the NegevBeer ShevaIsrael
| | - Benjamin Tam
- Department of ChemistryBen‐Gurion University of the NegevBeer ShevaIsrael
| | - Monica Einav
- Department of Life SciencesBen‐Gurion University of the NegevBeer ShevaIsrael,The Zlotowski Center for NeuroscienceBen‐Gurion University of the NegevBeer ShevaIsrael
| | - Barak Akabayov
- Department of ChemistryBen‐Gurion University of the NegevBeer ShevaIsrael
| | - Shimon Berstein
- Department of Life SciencesBen‐Gurion University of the NegevBeer ShevaIsrael
| | - Debra Toiber
- Department of Life SciencesBen‐Gurion University of the NegevBeer ShevaIsrael,The Zlotowski Center for NeuroscienceBen‐Gurion University of the NegevBeer ShevaIsrael
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13
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Gomez-Navarro N, Maldutyte J, Poljak K, Peak-Chew SY, Orme J, Bisnett BJ, Lamb CH, Boyce M, Gianni D, Miller EA. Selective inhibition of protein secretion by abrogating receptor-coat interactions during ER export. Proc Natl Acad Sci U S A 2022; 119:e2202080119. [PMID: 35901214 PMCID: PMC9351455 DOI: 10.1073/pnas.2202080119] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Accepted: 06/01/2022] [Indexed: 01/03/2023] Open
Abstract
Protein secretion is an essential process that drives cell growth, movement, and communication. Protein traffic within the secretory pathway occurs via transport intermediates that bud from one compartment and fuse with a downstream compartment to deliver their contents. Here, we explore the possibility that protein secretion can be selectively inhibited by perturbing protein-protein interactions that drive capture into transport vesicles. Human proprotein convertase subtilisin/kexin type 9 (PCSK9) is a determinant of cholesterol metabolism whose secretion is mediated by a specific cargo adaptor protein, SEC24A. We map a series of protein-protein interactions between PCSK9, its endoplasmic reticulum (ER) export receptor SURF4, and SEC24A that mediate secretion of PCSK9. We show that the interaction between SURF4 and SEC24A can be inhibited by 4-phenylbutyrate (4-PBA), a small molecule that occludes a cargo-binding domain of SEC24. This inhibition reduces secretion of PCSK9 and additional SURF4 clients that we identify by mass spectrometry, leaving other secreted cargoes unaffected. We propose that selective small-molecule inhibition of cargo recognition by SEC24 is a potential therapeutic intervention for atherosclerosis and other diseases that are modulated by secreted proteins.
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Affiliation(s)
- Natalia Gomez-Navarro
- Cell Biology Division, Medical Research Council Laboratory of Molecular Biology, Cambridge, CB2 0QH, United Kingdom
| | - Julija Maldutyte
- Cell Biology Division, Medical Research Council Laboratory of Molecular Biology, Cambridge, CB2 0QH, United Kingdom
| | - Kristina Poljak
- Cell Biology Division, Medical Research Council Laboratory of Molecular Biology, Cambridge, CB2 0QH, United Kingdom
| | - Sew-Yeu Peak-Chew
- Cell Biology Division, Medical Research Council Laboratory of Molecular Biology, Cambridge, CB2 0QH, United Kingdom
| | - Jonathon Orme
- Discovery Sciences, BioPharmaceuticals R&D, AstraZeneca, Cambridge, CB2 0AA, United Kingdom
| | - Brittany J. Bisnett
- Department of Biochemistry, Duke University School of Medicine, Durham, NC27710, USA
| | - Caitlin H. Lamb
- Department of Biochemistry, Duke University School of Medicine, Durham, NC27710, USA
| | - Michael Boyce
- Department of Biochemistry, Duke University School of Medicine, Durham, NC27710, USA
| | - Davide Gianni
- Discovery Sciences, BioPharmaceuticals R&D, AstraZeneca, Cambridge, CB2 0AA, United Kingdom
| | - Elizabeth A. Miller
- Cell Biology Division, Medical Research Council Laboratory of Molecular Biology, Cambridge, CB2 0QH, United Kingdom
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14
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Suga K, Yamamoto-Hijikata S, Terao Y, Akagawa K, Ushimaru M. Golgi stress induces upregulation of the ER-Golgi SNARE Syntaxin-5, altered βAPP processing, and Caspase-3-dependent apoptosis in NG108-15 cells. Mol Cell Neurosci 2022; 121:103754. [PMID: 35842170 DOI: 10.1016/j.mcn.2022.103754] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Revised: 05/29/2022] [Accepted: 07/07/2022] [Indexed: 01/06/2023] Open
Abstract
The involvement of secretory pathways and Golgi dysfunction in neuronal cells during Alzheimer's disease progression is poorly understood. Our previous overexpression and knockdown studies revealed that the intracellular protein level of Syntaxin-5, an endoplasmic reticulum-Golgi soluble N-ethylmaleimide-sensitive factor-attachment protein receptor (SNARE), modulates beta-amyloid precursor protein processing in neuronal cells. We recently showed that changes in endogenous Syntaxin-5 protein expression occur under stress induction. Syntaxin-5 was upregulated by endoplasmic reticulum stress but was degraded by Caspase-3 during apoptosis in neuronal cells. In addition, we showed that sustained endoplasmic reticulum stress promotes Caspase-3-dependent apoptosis during the later phase of the endoplasmic reticulum stress response in NG108-15 cells. In this study, to elucidate the consequences of secretory pathway dysfunction in beta-amyloid precursor protein processing that lead to neuronal cell death, we examined the effect of various stresses on endoplasmic reticulum-Golgi SNARE expression and beta-amyloid precursor protein processing. By using compounds to disrupt Golgi function, we show that Golgi stress promotes upregulation of the endoplasmic reticulum-Golgi SNARE Syntaxin-5, and prolonged stress causes Caspase-3-dependent apoptosis. Golgi stress induced intracellular beta-amyloid precursor protein accumulation and a concomitant decrease in total amyloid-beta production. We also examined the protective effect of the chemical chaperone 4-phenylbutylate on changes in amyloid-beta production and the activation of Caspase-3 induced by endoplasmic reticulum and Golgi stress. The compound alleviated the increase in the amyloid-beta 1-42/amyloid-beta 1-40 ratio induced by endoplasmic reticulum and Golgi stress. Furthermore, 4-phenylbutylate could rescue Caspase-3-dependent apoptosis induced by prolonged organelle stress. These results suggest that organelle stress originating from the endoplasmic reticulum and Golgi has a substantial impact on the amyloidogenic processing of beta-amyloid precursor protein and Caspase-3-dependent apoptosis, leading to neuronal cell death.
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Affiliation(s)
- Kei Suga
- Department of Chemistry, Kyorin University, Faculty of Medicine, Mitaka, Tokyo 181-8611, Japan; Department of Medical Physiology, Kyorin University, Faculty of Medicine, Mitaka, Tokyo 181-8611, Japan.
| | | | - Yasuo Terao
- Department of Medical Physiology, Kyorin University, Faculty of Medicine, Mitaka, Tokyo 181-8611, Japan
| | - Kimio Akagawa
- Department of Medical Physiology, Kyorin University, Faculty of Medicine, Mitaka, Tokyo 181-8611, Japan
| | - Makoto Ushimaru
- Department of Chemistry, Kyorin University, Faculty of Medicine, Mitaka, Tokyo 181-8611, Japan
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15
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Qian N, Li S, Tan X. The curious case of TMEM120A: Mechanosensor, fat regulator, or antiviral defender? Bioessays 2022; 44:e2200045. [PMID: 35419854 DOI: 10.1002/bies.202200045] [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: 02/21/2022] [Revised: 03/17/2022] [Accepted: 03/23/2022] [Indexed: 11/06/2022]
Abstract
Mechanical pain sensing, adipogenesis, and STING-dependent innate immunity seem three distinct biological processes without substantial relationships. Intriguingly, TMEM120A, a transmembrane protein, has been shown to detect mechanical pain stimuli as a mechanosensitive channel, contribute to adipocyte differentiation/function by regulating genome organization and promote STING trafficking to active cellular innate immune response. However, the role of TMEM120A as a mechanosensitive channel was challenged by recent studies which cannot reproduce data supporting its role in mechanosensing. Furthermore, the molecular mechanism by which TMEM120A contributes to adipocyte differentiation/function and promotes STING trafficking remains elusive. In this review, we discuss these multiple proposed functions of TMEM120A and hypothesize the molecular mechanism underlying TMEM120A's role in fatty acid metabolism and STING signaling.
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Affiliation(s)
- Nianchao Qian
- Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, School of Pharmaceutical Sciences, Tsinghua University, Beijing, China
| | - Shuo Li
- Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, School of Pharmaceutical Sciences, Tsinghua University, Beijing, China
| | - Xu Tan
- Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, School of Pharmaceutical Sciences, Tsinghua University, Beijing, China.,Tsinghua-Peking Center for Life Sciences, Beijing, China.,Center for Infectious Disease Research, School of Medicine, Tsinghua University, Beijing, China
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16
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A tango for coats and membranes: New insights into ER-to-Golgi traffic. Cell Rep 2022; 38:110258. [DOI: 10.1016/j.celrep.2021.110258] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 11/17/2021] [Accepted: 12/21/2021] [Indexed: 12/30/2022] Open
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17
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Lu CL, Ortmeier S, Brudvig J, Moretti T, Cain J, Boyadjiev SA, Weimer JM, Kim J. Collagen has a unique SEC24 preference for efficient export from the endoplasmic reticulum. Traffic 2022; 23:81-93. [PMID: 34761479 PMCID: PMC8692420 DOI: 10.1111/tra.12826] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 10/28/2021] [Accepted: 10/29/2021] [Indexed: 01/03/2023]
Abstract
SEC24 is mainly involved in cargo sorting during COPII vesicle assembly. There are four SEC24 paralogs (A-D) in vertebrates, which are classified into two subgroups (SEC24A/B and SEC24C/D). Pathological mutations in SEC24D cause osteogenesis imperfecta with craniofacial dysplasia in humans. sec24d mutant fish also recapitulate the phenotypes. Consistent with the skeletal phenotypes, the secretion of collagen was severely defective in mutant fish, emphasizing the importance of SEC24D in collagen secretion. However, SEC24D patient-derived fibroblasts show only a mild secretion phenotype, suggesting tissue-specificity in the secretion process. Using Sec24d KO mice and cultured cells, we show that SEC24A and SEC24B also contribute to endoplasmic reticulum (ER) export of procollagen. In contrast, fibronectin 1 requires either SEC24C or SEC24D for ER export. On the basis of our results, we propose that procollagen interacts with multiple SEC24 paralogs for efficient export from the ER, and that this is the basis for tissue-specific phenotypes resulting from SEC24 paralog deficiency.
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Affiliation(s)
- Chung-Ling Lu
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, 50011, USA
| | - Steven Ortmeier
- Pediatrics and Rare Diseases Group, Sanford Research, Sioux Falls, SD, 57104, USA
| | - Jon Brudvig
- Pediatrics and Rare Diseases Group, Sanford Research, Sioux Falls, SD, 57104, USA
| | - Tamara Moretti
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, 50011, USA
| | - Jacob Cain
- Pediatrics and Rare Diseases Group, Sanford Research, Sioux Falls, SD, 57104, USA
| | - Simeon A. Boyadjiev
- Department of Pediatrics, University of California Davis School of Medicine, Sacramento, CA, 95817, USA
| | - Jill M. Weimer
- Pediatrics and Rare Diseases Group, Sanford Research, Sioux Falls, SD, 57104, USA
| | - Jinoh Kim
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, 50011, USA,To who correspondence should be addressed: Jinoh Kim, 2086 Vet Med, 1800 Christensen Drive, Iowa State University, Ames, IA 50011, , Tel: 515-294-3401
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18
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Sargeant J, Seiler DK, Costain T, Madreiter-Sokolowski CT, Gordon DE, Peden AA, Malli R, Graier WF, Hay JC. ALG-2 and peflin regulate COPII targeting and secretion in response to calcium signaling. J Biol Chem 2021; 297:101393. [PMID: 34762908 PMCID: PMC8671942 DOI: 10.1016/j.jbc.2021.101393] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 11/01/2021] [Accepted: 11/05/2021] [Indexed: 02/05/2023] Open
Abstract
ER-to-Golgi transport is the first step in the constitutive secretory pathway, which, unlike regulated secretion, is believed to proceed nonstop independent of Ca2+ flux. However, here we demonstrate that penta-EF hand (PEF) proteins ALG-2 and peflin constitute a hetero-bifunctional COPII regulator that responds to Ca2+ signaling by adopting one of several distinct activity states. Functionally, these states can adjust the rate of ER export of COPII-sorted cargos up or down by ∼50%. We found that at steady-state Ca2+, ALG-2/peflin hetero-complexes bind to ER exit sites (ERES) through the ALG-2 subunit to confer a low, buffered secretion rate, while peflin-lacking ALG-2 complexes markedly stimulate secretion. Upon Ca2+ signaling, ALG-2 complexes lacking peflin can either increase or decrease the secretion rate depending on signaling intensity and duration-phenomena that could contribute to cellular growth and intercellular communication following secretory increases or protection from excitotoxicity and infection following decreases. In epithelial normal rat kidney (NRK) cells, the Ca2+-mobilizing agonist ATP causes ALG-2 to depress ER export, while in neuroendocrine PC12 cells, Ca2+ mobilization by ATP results in ALG-2-dependent enhancement of secretion. Furthermore, distinct Ca2+ signaling patterns in NRK cells produce opposing ALG-2-dependent effects on secretion. Mechanistically, ALG-2-dependent depression of secretion involves decreased levels of the COPII outer shell and increased peflin targeting to ERES, while ALG-2-dependent enhancement of secretion involves increased COPII outer shell and decreased peflin at ERES. These data provide insights into how PEF protein dynamics affect secretion of important physiological cargoes such as collagen I and significantly impact ER stress.
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Affiliation(s)
- John Sargeant
- Division of Biological Sciences, Center for Structural and Functional Neuroscience, University of Montana, Missoula, Montana, USA
| | - Danette Kowal Seiler
- Division of Biological Sciences, Center for Structural and Functional Neuroscience, University of Montana, Missoula, Montana, USA
| | - Tucker Costain
- Division of Biological Sciences, Center for Structural and Functional Neuroscience, University of Montana, Missoula, Montana, USA
| | | | - David E Gordon
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, California, USA
| | - Andrew A Peden
- Department of Biomedical Science and Centre for Membrane Interactions and Dynamics, The University of Sheffield, Sheffield, United Kingdom
| | - Roland Malli
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Graz, Austria
| | - Wolfgang F Graier
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Graz, Austria
| | - Jesse C Hay
- Division of Biological Sciences, Center for Structural and Functional Neuroscience, University of Montana, Missoula, Montana, USA.
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19
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The Unfolded Protein Response as a Guardian of the Secretory Pathway. Cells 2021; 10:cells10112965. [PMID: 34831188 PMCID: PMC8616143 DOI: 10.3390/cells10112965] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 10/27/2021] [Accepted: 10/29/2021] [Indexed: 02/07/2023] Open
Abstract
The endoplasmic reticulum (ER) is the major site of membrane biogenesis in most eukaryotic cells. As the entry point to the secretory pathway, it handles more than 10,000 different secretory and membrane proteins. The insertion of proteins into the membrane, their folding, and ER exit are affected by the lipid composition of the ER membrane and its collective membrane stiffness. The ER is also a hotspot of lipid biosynthesis including sterols, glycerophospholipids, ceramides and neural storage lipids. The unfolded protein response (UPR) bears an evolutionary conserved, dual sensitivity to both protein-folding imbalances in the ER lumen and aberrant compositions of the ER membrane, referred to as lipid bilayer stress (LBS). Through transcriptional and non-transcriptional mechanisms, the UPR upregulates the protein folding capacity of the ER and balances the production of proteins and lipids to maintain a functional secretory pathway. In this review, we discuss how UPR transducers sense unfolded proteins and LBS with a particular focus on their role as guardians of the secretory pathway.
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20
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Pharmacological targeting of endoplasmic reticulum stress in disease. Nat Rev Drug Discov 2021; 21:115-140. [PMID: 34702991 DOI: 10.1038/s41573-021-00320-3] [Citation(s) in RCA: 181] [Impact Index Per Article: 60.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/15/2021] [Indexed: 02/08/2023]
Abstract
The accumulation of misfolded proteins in the endoplasmic reticulum (ER) leads to ER stress, resulting in activation of the unfolded protein response (UPR) that aims to restore protein homeostasis. However, the UPR also plays an important pathological role in many diseases, including metabolic disorders, cancer and neurological disorders. Over the last decade, significant effort has been invested in targeting signalling proteins involved in the UPR and an array of drug-like molecules is now available. However, these molecules have limitations, the understanding of which is crucial for their development into therapies. Here, we critically review the existing ER stress and UPR-directed drug-like molecules, highlighting both their value and their limitations.
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21
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Lu CL, Kim J. Craniofacial Diseases Caused by Defects in Intracellular Trafficking. Genes (Basel) 2021; 12:726. [PMID: 34068038 PMCID: PMC8152478 DOI: 10.3390/genes12050726] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 05/10/2021] [Accepted: 05/11/2021] [Indexed: 12/12/2022] Open
Abstract
Cells use membrane-bound carriers to transport cargo molecules like membrane proteins and soluble proteins, to their destinations. Many signaling receptors and ligands are synthesized in the endoplasmic reticulum and are transported to their destinations through intracellular trafficking pathways. Some of the signaling molecules play a critical role in craniofacial morphogenesis. Not surprisingly, variants in the genes encoding intracellular trafficking machinery can cause craniofacial diseases. Despite the fundamental importance of the trafficking pathways in craniofacial morphogenesis, relatively less emphasis is placed on this topic, thus far. Here, we describe craniofacial diseases caused by lesions in the intracellular trafficking machinery and possible treatment strategies for such diseases.
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Affiliation(s)
| | - Jinoh Kim
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA;
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22
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Chen SZ, Ling Y, Yu LX, Song YT, Chen XF, Cao QQ, Yu H, Chen C, Tang JJ, Fan ZC, Miao YS, Dong YP, Tao JY, Monga SPS, Wen W, Wang HY. 4-phenylbutyric acid promotes hepatocellular carcinoma via initiating cancer stem cells through activation of PPAR-α. Clin Transl Med 2021; 11:e379. [PMID: 33931972 PMCID: PMC8087947 DOI: 10.1002/ctm2.379] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 03/16/2021] [Accepted: 03/18/2021] [Indexed: 12/12/2022] Open
Abstract
Background and aims 4‐phenylbutyric acid (4‐PBA) is a low molecular weight fatty acid that is used in clinical practice to treat inherited urea cycle disorders. In previous reports, it acted as a chemical chaperone inhibiting endoplasmic reticulum (ER) stress and unfolded protein response signaling. A few studies have suggested its function against hepatic fibrosis in mice models. However, its role in hepatocarcinogenesis remained unknown. Methods 4‐PBA was administered alone or in combination with diethylnitrosamine to investigate its long‐term effect on liver tumorigenesis. The role of 4‐PBA in oncogene‐induced hepatocellular carcinoma (HCC) mice model using sleeping beauty system co‐expressed with hMet and β‐catenin point mutation (S45Y) was also observed. RNA‐seq and PCR array were used to screen the pathways and genes involved. In vitro and in vivo studies were conducted to explore the effect of 4‐PBA on liver and validate the underlying mechanism. Results 4‐PBA alone didn't cause liver tumor in long term. However, it promoted liver tumorigenesis in HCC mice models via initiation of liver cancer stem cells (LCSCs) through Wnt5b‐Fzd5 mediating β‐catenin signaling. Peroxisome proliferator‐activated receptors (PPAR)‐α induced by 4‐PBA was responsible for the activation of β‐catenin signaling. Thus, intervention of PPAR‐α reversed 4‐PBA‐induced initiation of LCSCs and HCC development in vivo. Further study revealed that 4‐PBA could not only upregulate the expression of PPAR‐α transcriptionally but also enhance its stabilization via protecting it from proteolysis. Moreover, high PPAR‐α expression predicted poor prognosis in HCC patients. Conclusions 4‐PBA could upregulate PPAR‐α to initiate LCSCs by activating β‐catenin signaling pathway, promoting HCC at early stage. Therefore, more discretion should be taken to monitor the potential tumor‐promoting effect of 4‐PBA under HCC‐inducing environment.
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Affiliation(s)
- Shu-Zhen Chen
- National Center for Liver Cancer, Second Military Medical University, Shanghai, China.,International Cooperation Laboratory on Signal Transduction, Eastern Hepatobiliary Surgery Hospital, Second Military Medical University, Shanghai, China
| | - Yan Ling
- National Center for Liver Cancer, Second Military Medical University, Shanghai, China.,International Cooperation Laboratory on Signal Transduction, Eastern Hepatobiliary Surgery Hospital, Second Military Medical University, Shanghai, China
| | - Le-Xing Yu
- National Center for Liver Cancer, Second Military Medical University, Shanghai, China.,International Cooperation Laboratory on Signal Transduction, Eastern Hepatobiliary Surgery Hospital, Second Military Medical University, Shanghai, China
| | - Yu-Ting Song
- National Center for Liver Cancer, Second Military Medical University, Shanghai, China.,International Cooperation Laboratory on Signal Transduction, Eastern Hepatobiliary Surgery Hospital, Second Military Medical University, Shanghai, China.,Model Animal Research Center, Nanjing University, Nanjing, Jiangsu Province, China
| | - Xiao-Fei Chen
- School of Pharmacy, Second Military Medical University, Shanghai, China
| | - Qi-Qi Cao
- National Center for Liver Cancer, Second Military Medical University, Shanghai, China.,International Cooperation Laboratory on Signal Transduction, Eastern Hepatobiliary Surgery Hospital, Second Military Medical University, Shanghai, China
| | - Han Yu
- National Center for Liver Cancer, Second Military Medical University, Shanghai, China.,International Cooperation Laboratory on Signal Transduction, Eastern Hepatobiliary Surgery Hospital, Second Military Medical University, Shanghai, China
| | - Can Chen
- National Center for Liver Cancer, Second Military Medical University, Shanghai, China.,International Cooperation Laboratory on Signal Transduction, Eastern Hepatobiliary Surgery Hospital, Second Military Medical University, Shanghai, China.,Fujian Medical University, Fuzhou, Fujian Province, China
| | - Jiao-Jiao Tang
- National Center for Liver Cancer, Second Military Medical University, Shanghai, China.,Cancer Research Center, The First Affiliated Hospital of University of Science and Technology of China, Hefei, Anhui Province, China
| | - Zhe-Cai Fan
- National Center for Liver Cancer, Second Military Medical University, Shanghai, China
| | - Yu-Shan Miao
- National Center for Liver Cancer, Second Military Medical University, Shanghai, China.,International Cooperation Laboratory on Signal Transduction, Eastern Hepatobiliary Surgery Hospital, Second Military Medical University, Shanghai, China
| | - Ya-Ping Dong
- National Center for Liver Cancer, Second Military Medical University, Shanghai, China.,International Cooperation Laboratory on Signal Transduction, Eastern Hepatobiliary Surgery Hospital, Second Military Medical University, Shanghai, China.,Fujian Medical University, Fuzhou, Fujian Province, China
| | - Jun-Yan Tao
- Department of Pathology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Satdarshan P S Monga
- Department of Pathology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Wen Wen
- National Center for Liver Cancer, Second Military Medical University, Shanghai, China.,International Cooperation Laboratory on Signal Transduction, Eastern Hepatobiliary Surgery Hospital, Second Military Medical University, Shanghai, China
| | - Hong-Yang Wang
- National Center for Liver Cancer, Second Military Medical University, Shanghai, China.,International Cooperation Laboratory on Signal Transduction, Eastern Hepatobiliary Surgery Hospital, Second Military Medical University, Shanghai, China.,Model Animal Research Center, Nanjing University, Nanjing, Jiangsu Province, China.,State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China.,Fujian Medical University, Fuzhou, Fujian Province, China.,Cancer Research Center, The First Affiliated Hospital of University of Science and Technology of China, Hefei, Anhui Province, China
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23
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Shomron O, Nevo-Yassaf I, Aviad T, Yaffe Y, Zahavi EE, Dukhovny A, Perlson E, Brodsky I, Yeheskel A, Pasmanik-Chor M, Mironov A, Beznoussenko GV, Mironov AA, Sklan EH, Patterson GH, Yonemura Y, Sannai M, Kaether C, Hirschberg K. COPII collar defines the boundary between ER and ER exit site and does not coat cargo containers. J Cell Biol 2021; 220:211990. [PMID: 33852719 PMCID: PMC8054201 DOI: 10.1083/jcb.201907224] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 01/14/2021] [Accepted: 03/11/2021] [Indexed: 12/13/2022] Open
Abstract
COPII and COPI mediate the formation of membrane vesicles translocating in opposite directions within the secretory pathway. Live-cell and electron microscopy revealed a novel mode of function for COPII during cargo export from the ER. COPII is recruited to membranes defining the boundary between the ER and ER exit sites, facilitating selective cargo concentration. Using direct observation of living cells, we monitored cargo selection processes, accumulation, and fission of COPII-free ERES membranes. CRISPR/Cas12a tagging, the RUSH system, and pharmaceutical and genetic perturbations of ER-Golgi transport demonstrated that the COPII coat remains bound to the ER–ERES boundary during protein export. Manipulation of the cargo-binding domain in COPII Sec24B prohibits cargo accumulation in ERES. These findings suggest a role for COPII in selecting and concentrating exported cargo rather than coating Golgi-bound carriers. These findings transform our understanding of coat proteins’ role in ER-to-Golgi transport.
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Affiliation(s)
- Olga Shomron
- Department of Pathology, Sackler School of Medicine, Tel-Aviv University, Tel Aviv, Israel
| | - Inbar Nevo-Yassaf
- Department of Pathology, Sackler School of Medicine, Tel-Aviv University, Tel Aviv, Israel
| | - Tamar Aviad
- Department of Pathology, Sackler School of Medicine, Tel-Aviv University, Tel Aviv, Israel
| | - Yakey Yaffe
- Department of Pathology, Sackler School of Medicine, Tel-Aviv University, Tel Aviv, Israel
| | - Eitan Erez Zahavi
- Department of Physiology and Pharmacology, Sackler School of Medicine, Tel-Aviv University, Tel Aviv, Israel
| | - Anna Dukhovny
- Department of Clinical Immunology and Microbiology, Sackler School of Medicine, Tel-Aviv University, Tel Aviv, Israel
| | - Eran Perlson
- Department of Physiology and Pharmacology, Sackler School of Medicine, Tel-Aviv University, Tel Aviv, Israel
| | - Ilya Brodsky
- Lomonosov Moscow State University, Andrey N. Belozersky Institute for Physico-Chemical Biology, Moscow, Russia
| | - Adva Yeheskel
- Bioinformatics Unit, George S. Wise Faculty of Life Sciences, Tel-Aviv University, Tel Aviv, Israel
| | - Metsada Pasmanik-Chor
- Bioinformatics Unit, George S. Wise Faculty of Life Sciences, Tel-Aviv University, Tel Aviv, Israel
| | - Anna Mironov
- Istituto Firc di Oncologia Molecolare, Fondazione Istituto Fondazione Italiana per la Ricerca sul Cancro di Oncologia Molecolare, Milan, Italy
| | - Galina V Beznoussenko
- Istituto Firc di Oncologia Molecolare, Fondazione Istituto Fondazione Italiana per la Ricerca sul Cancro di Oncologia Molecolare, Milan, Italy
| | - Alexander A Mironov
- Istituto Firc di Oncologia Molecolare, Fondazione Istituto Fondazione Italiana per la Ricerca sul Cancro di Oncologia Molecolare, Milan, Italy
| | - Ella H Sklan
- Department of Clinical Immunology and Microbiology, Sackler School of Medicine, Tel-Aviv University, Tel Aviv, Israel
| | - George H Patterson
- Section on Biophotonics, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, Rockville, MD
| | - Yoji Yonemura
- Leibniz Institute on Aging, Fritz Lipmann Institute, Jena, Germany
| | - Mara Sannai
- Leibniz Institute on Aging, Fritz Lipmann Institute, Jena, Germany
| | | | - Koret Hirschberg
- Department of Pathology, Sackler School of Medicine, Tel-Aviv University, Tel Aviv, Israel
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24
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Garibaldi N, Contento BM, Babini G, Morini J, Siciliani S, Biggiogera M, Raspanti M, Marini JC, Rossi A, Forlino A, Besio R. Targeting cellular stress in vitro improves osteoblast homeostasis, matrix collagen content and mineralization in two murine models of osteogenesis imperfecta. Matrix Biol 2021; 98:1-20. [PMID: 33798677 PMCID: PMC11162743 DOI: 10.1016/j.matbio.2021.03.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 03/26/2021] [Accepted: 03/26/2021] [Indexed: 12/14/2022]
Abstract
Most cases of dominantly inherited osteogenesis imperfecta (OI) are caused by glycine substitutions in the triple helical domain of type I collagen α chains, which delay collagen folding, and cause the synthesis of collagen triple helical molecules with abnormal structure and post-translational modification. A variable extent of mutant collagen ER retention and other secondary mutation effects perturb osteoblast homeostasis and impair bone matrix quality. Amelioration of OI osteoblast homeostasis could be beneficial both to osteoblast anabolic activity and to the content of the extracellular matrix they deposit. Therefore, the effect of the chemical chaperone 4-phenylbutyrate (4-PBA) on cell homeostasis, collagen trafficking, matrix production and mineralization was investigated in primary osteoblasts from two murine models of moderate OI, Col1a1+/G349C and Col1a2+/G610C. At the cellular level, 4-PBA prevented intracellular accumulation of collagen and increased protein secretion, reducing aggregates within the mutant cells and normalizing ER morphology. At the extracellular level, increased collagen incorporation into matrix, associated with more mature collagen fibrils, was observed in osteoblasts from both models. 4-PBA also promoted OI osteoblast mineral deposition by increasing alkaline phosphatase expression and activity. Targeting osteoblast stress with 4-PBA improved both cellular and matrix abnormalities in culture, supporting further in vivo studies of its effect on bone tissue composition, strength and mineralization as a potential treatment for classical OI.
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Affiliation(s)
- Nadia Garibaldi
- Department of Molecular Medicine, Biochemistry Unit, University of Pavia, Pavia, Italy; Istituto Universitario di Studi Superiori - IUSS, Pavia, Italy.
| | - Barbara M Contento
- Department of Molecular Medicine, Biochemistry Unit, University of Pavia, Pavia, Italy.
| | | | - Jacopo Morini
- Department of Physics, University of Pavia, Pavia, Italy.
| | - Stella Siciliani
- Department of Biology and Biotechnology, University of Pavia, Pavia, Italy.
| | - Marco Biggiogera
- Department of Biology and Biotechnology, University of Pavia, Pavia, Italy.
| | - Mario Raspanti
- Department of Medicine and Surgery, University of Insubria, Varese, Italy.
| | - Joan C Marini
- Bone and Extracellular Matrix Branch, NICHD, National Institute of Health, Bethesda, MD 20892, USA.
| | - Antonio Rossi
- Department of Molecular Medicine, Biochemistry Unit, University of Pavia, Pavia, Italy.
| | - Antonella Forlino
- Department of Molecular Medicine, Biochemistry Unit, University of Pavia, Pavia, Italy.
| | - Roberta Besio
- Department of Molecular Medicine, Biochemistry Unit, University of Pavia, Pavia, Italy.
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25
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A virtuous cycle operated by ERp44 and ERGIC-53 guarantees proteostasis in the early secretory compartment. iScience 2021; 24:102244. [PMID: 33763635 PMCID: PMC7973864 DOI: 10.1016/j.isci.2021.102244] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 02/01/2021] [Accepted: 02/25/2021] [Indexed: 01/13/2023] Open
Abstract
The composition of the secretome depends on the combined action of cargo receptors that facilitate protein transport and sequential checkpoints that restrict it to native conformers. Acting after endoplasmic reticulum (ER)-resident chaperones, ERp44 retrieves its clients from downstream compartments. To guarantee efficient quality control, ERp44 should exit the ER as rapidly as its clients, or more. Here, we show that appending ERp44 to different cargo proteins increases their secretion rates. ERp44 binds the cargo receptor ER-Golgi intermediate compartment (ERGIC)-53 in the ER to negotiate preferential loading into COPII vesicles. Silencing ERGIC-53, or competing for its COPII binding with 4-phenylbutyrate, causes secretion of Prdx4, an enzyme that relies on ERp44 for intracellular localization. In more acidic, zinc-rich downstream compartments, ERGIC-53 releases its clients and ERp44, which can bind and retrieve non-native conformers via KDEL receptors. By coupling the transport of cargoes and inspector proteins, cells ensure efficiency and fidelity of secretion.
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26
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Gomez-Navarro N, Melero A, Li XH, Boulanger J, Kukulski W, Miller EA. Cargo crowding contributes to sorting stringency in COPII vesicles. J Cell Biol 2021; 219:151777. [PMID: 32406500 PMCID: PMC7300426 DOI: 10.1083/jcb.201806038] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 03/11/2020] [Accepted: 04/24/2020] [Indexed: 02/05/2023] Open
Abstract
Accurate maintenance of organelle identity in the secretory pathway relies on retention and retrieval of resident proteins. In the endoplasmic reticulum (ER), secretory proteins are packaged into COPII vesicles that largely exclude ER residents and misfolded proteins by mechanisms that remain unresolved. Here we combined biochemistry and genetics with correlative light and electron microscopy (CLEM) to explore how selectivity is achieved. Our data suggest that vesicle occupancy contributes to ER retention: in the absence of abundant cargo, nonspecific bulk flow increases. We demonstrate that ER leakage is influenced by vesicle size and cargo occupancy: overexpressing an inert cargo protein or reducing vesicle size restores sorting stringency. We propose that cargo recruitment into vesicles creates a crowded lumen that drives selectivity. Retention of ER residents thus derives in part from the biophysical process of cargo enrichment into a constrained spherical membrane-bound carrier.
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Affiliation(s)
| | - Alejandro Melero
- Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
| | - Xiao-Han Li
- Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
| | - Jérôme Boulanger
- Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
| | - Wanda Kukulski
- Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
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27
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Abstract
The functions of coat protein complex II (COPII) coats in cargo packaging and the creation of vesicles at the endoplasmic reticulum are conserved in eukaryotic protein secretion. Standard COPII vesicles, however, cannot handle the secretion of metazoan-specific cargoes such as procollagens, apolipoproteins, and mucins. Metazoans have thus evolved modules centered on proteins like TANGO1 (transport and Golgi organization 1) to engage COPII coats and early secretory pathway membranes to engineer a novel mode of cargo export at the endoplasmic reticulum.
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Affiliation(s)
- I Raote
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona 08003, Spain; ,
| | - V Malhotra
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona 08003, Spain; , .,Universitat Pompeu Fabra (UPF), Barcelona 08002, Spain.,Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona 08010, Spain
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28
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Bradley KL, Stokes CA, Marciniak SJ, Parker LC, Condliffe AM. Role of unfolded proteins in lung disease. Thorax 2021; 76:92-99. [PMID: 33077618 PMCID: PMC7803888 DOI: 10.1136/thoraxjnl-2019-213738] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2019] [Revised: 09/18/2020] [Accepted: 09/20/2020] [Indexed: 01/01/2023]
Abstract
The lungs are exposed to a range of environmental toxins (including cigarette smoke, air pollution, asbestos) and pathogens (bacterial, viral and fungal), and most respiratory diseases are associated with local or systemic hypoxia. All of these adverse factors can trigger endoplasmic reticulum (ER) stress. The ER is a key intracellular site for synthesis of secretory and membrane proteins, regulating their folding, assembly into complexes, transport and degradation. Accumulation of misfolded proteins within the lumen results in ER stress, which activates the unfolded protein response (UPR). Effectors of the UPR temporarily reduce protein synthesis, while enhancing degradation of misfolded proteins and increasing the folding capacity of the ER. If successful, homeostasis is restored and protein synthesis resumes, but if ER stress persists, cell death pathways are activated. ER stress and the resulting UPR occur in a range of pulmonary insults and the outcome plays an important role in many respiratory diseases. The UPR is triggered in the airway of patients with several respiratory diseases and in corresponding experimental models. ER stress has been implicated in the initiation and progression of pulmonary fibrosis, and evidence is accumulating suggesting that ER stress occurs in obstructive lung diseases (particularly in asthma), in pulmonary infections (some viral infections and in the setting of the cystic fibrosis airway) and in lung cancer. While a number of small molecule inhibitors have been used to interrogate the role of the UPR in disease models, many of these tools have complex and off-target effects, hence additional evidence (eg, from genetic manipulation) may be required to support conclusions based on the impact of such pharmacological agents. Aberrant activation of the UPR may be linked to disease pathogenesis and progression, but at present, our understanding of the context-specific and disease-specific mechanisms linking these processes is incomplete. Despite this, the ability of the UPR to defend against ER stress and influence a range of respiratory diseases is becoming increasingly evident, and the UPR is therefore attracting attention as a prospective target for therapeutic intervention strategies.
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Affiliation(s)
- Kirsty L Bradley
- Department of Infection, Immunity and Cardiovascular Diseases, The University of Sheffield, Sheffield, UK
| | - Clare A Stokes
- Department of Infection, Immunity and Cardiovascular Diseases, The University of Sheffield, Sheffield, UK
| | | | - Lisa C Parker
- Department of Infection, Immunity and Cardiovascular Diseases, The University of Sheffield, Sheffield, UK
| | - Alison M Condliffe
- Department of Infection, Immunity and Cardiovascular Diseases, The University of Sheffield, Sheffield, UK
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29
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Dvela-Levitt M, Shaw JL, Greka A. A Rare Kidney Disease To Cure Them All? Towards Mechanism-Based Therapies for Proteinopathies. Trends Mol Med 2020; 27:394-409. [PMID: 33341352 DOI: 10.1016/j.molmed.2020.11.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 11/20/2020] [Accepted: 11/20/2020] [Indexed: 12/30/2022]
Abstract
Autosomal dominant tubulointerstitial kidney diseases (ADTKDs) are a group of rare genetic diseases that lead to kidney failure. Mutations in the MUC1 gene cause ADTKD-MUC1 (MUC1 kidney disease, MKD), a disorder with no available therapies. Recent studies have identified the molecular and cellular mechanisms that drive MKD disease pathogenesis. Armed with patient-derived cell lines and pluripotent stem cell (iPSC)-derived kidney organoids, it was found that MKD is a toxic proteinopathy caused by the intracellular accumulation of misfolded MUC1 protein in the early secretory pathway. We discuss the advantages of studying rare monogenic kidney diseases, describe effective patient-derived model systems, and highlight recent mechanistic insights into protein quality control that have implications for additional proteinopathies beyond rare kidney diseases.
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Affiliation(s)
- Moran Dvela-Levitt
- The Broad Institute of Massachusetts Institute of Technology (MIT) and Harvard, Cambridge, MA, USA; Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Jillian L Shaw
- The Broad Institute of Massachusetts Institute of Technology (MIT) and Harvard, Cambridge, MA, USA
| | - Anna Greka
- The Broad Institute of Massachusetts Institute of Technology (MIT) and Harvard, Cambridge, MA, USA; Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA.
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30
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Gomez-Navarro N, Boulanger J, Miller EA. The Ubp3/Bre5 deubiquitylation complex modulates COPII vesicle formation. Traffic 2020; 21:702-711. [PMID: 32975860 PMCID: PMC7711842 DOI: 10.1111/tra.12766] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 09/17/2020] [Accepted: 09/18/2020] [Indexed: 11/12/2022]
Abstract
The appropriate delivery of secretory proteins to the correct subcellular destination is an essential cellular process. In the endoplasmic reticulum (ER), secretory proteins are captured into COPII vesicles that generally exclude ER resident proteins and misfolded proteins. We previously characterized a collection of yeast mutants that fail to enforce this sorting stringency and improperly secrete the ER chaperone, Kar2 (Copic et al., Genetics 2009). Here, we used the emp24Δ mutant strain that secretes Kar2 to identify candidate proteins that might regulate ER export, reasoning that loss of regulatory proteins would restore sorting stringency. We find that loss of the deubiquitylation complex Ubp3/Bre5 reverses all of the known phenotypes of the emp24Δ mutant, and similarly reverses Kar2 secretion of many other ER retention mutants. Based on a combination of genetic interactions and live cell imaging, we conclude that Ubp3 and Bre5 modulate COPII coat assembly at ER exit sites. Therefore, we propose that Ubp3/Bre5 influences the rate of vesicle formation from the ER that in turn can impact ER quality control events.
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Affiliation(s)
| | - Jérôme Boulanger
- Cell Biology Division, MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Elizabeth A Miller
- Cell Biology Division, MRC Laboratory of Molecular Biology, Cambridge, UK
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31
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Oommen D, Kizhakkedath P, Jawabri AA, Varghese DS, Ali BR. Proteostasis Regulation in the Endoplasmic Reticulum: An Emerging Theme in the Molecular Pathology and Therapeutic Management of Familial Hypercholesterolemia. Front Genet 2020; 11:570355. [PMID: 33173538 PMCID: PMC7538668 DOI: 10.3389/fgene.2020.570355] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Accepted: 08/31/2020] [Indexed: 02/05/2023] Open
Abstract
Familial hypercholesterolemia (FH) is an autosomal genetic disease characterized by high serum low-density lipoprotein (LDL) content leading to premature coronary artery disease. The main genetic and molecular causes of FH are mutations in low-density lipoprotein receptor gene (LDLR) resulting in the non-clearance of LDL from the blood by hepatocytes and consequently the formation of plaques. LDLR is synthesized and glycosylated in the endoplasmic reticulum (ER) and then transported to the plasma membrane via Golgi. It is estimated that more than 50% of reported FH-causing mutations in LDLR result in misfolded proteins that are transport-defective and hence retained in ER. ER accumulation of misfolded proteins causes ER-stress and activates unfolded protein response (UPR). UPR aids protein folding, blocks further protein synthesis, and eliminates misfolded proteins via ER-associated degradation (ERAD) to alleviate ER stress. Various studies demonstrated that ER-retained LDLR mutants are subjected to ERAD. Interestingly, chemical chaperones and genetic or pharmacological inhibition of ERAD have been reported to rescue the transport defective mutant LDLR alleles from ERAD and restore their ER-Golgi transport resulting in the expression of functional plasma membrane LDLR. This suggests the possibility of pharmacological modulation of proteostasis in the ER as a therapeutic strategy for FH. In this review, we picture a detailed analysis of UPR and the ERAD processes activated by ER-retained LDLR mutants associated with FH. In addition, we discuss and critically evaluate the potential role of chemical chaperones and ERAD modulators in the therapeutic management of FH.
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Affiliation(s)
- Deepu Oommen
- Department of Genetics and Genomics, College of Medicine and Health Sciences, United Arab Emirates University, Al-Ain, United Arab Emirates
| | - Praseetha Kizhakkedath
- Department of Genetics and Genomics, College of Medicine and Health Sciences, United Arab Emirates University, Al-Ain, United Arab Emirates
| | - Aseel A Jawabri
- Department of Genetics and Genomics, College of Medicine and Health Sciences, United Arab Emirates University, Al-Ain, United Arab Emirates
| | - Divya Saro Varghese
- Department of Genetics and Genomics, College of Medicine and Health Sciences, United Arab Emirates University, Al-Ain, United Arab Emirates
| | - Bassam R Ali
- Department of Genetics and Genomics, College of Medicine and Health Sciences, United Arab Emirates University, Al-Ain, United Arab Emirates.,Department of Pathology, College of Medicine and Health Sciences, United Arab Emirates University, Al-Ain, United Arab Emirates.,Zayed Center for Health Sciences, College of Medicine and Health Sciences, United Arab Emirates University, Al-Ain, United Arab Emirates
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32
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Braun D, Schweizer U. The Protein Translocation Defect of MCT8 L291R Is Rescued by Sodium Phenylbutyrate. Eur Thyroid J 2020; 9:269-280. [PMID: 33088796 PMCID: PMC7548921 DOI: 10.1159/000507439] [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] [Received: 12/20/2019] [Accepted: 03/24/2020] [Indexed: 11/19/2022] Open
Abstract
INTRODUCTION The monocarboxylate transporter 8 (MCT8; SLC16A2) is a specific transporter for thyroid hormones. MCT8 deficiency, formerly known as the Allan-Herndon-Dudley syndrome, is a rare genetic disease that leads to neurological impairments and muscle weakness. Current experimental treatment options rely on thyromimetic agonists that do not depend on MCT8 for cellular uptake. Another approach comes from studies with the chemical chaperone sodium phenylbutyrate (NaPB), which was able to stabilize MCT8 mutants having protein folding defects in vitro. In addition, NaPB is known as a compound that assists with plasma membrane translocation. OBJECTIVE The pathogenic MCT8L291R leads to the same severe neurological impairments found for other MCT8-deficient patients but, unexpectedly, lacks alterations in plasma 3,3',5-triiodothyronine (T3) levels. Here we tried to unravel the underlying mechanism of MCT8 deficiency and tested whether the pathogenic MCT8L291R mutant responds to NaPB treatment. Therefore, we overexpressed the mutant in Madin-Darby canine kidney cells in the human choriocarcinoma cell line JEG1 and in COS7 cells of African green monkey origin. RESULTS In our recent study we describe that the MCT8L291R mutation most likely leads to a translocation defect. The pathogenic mutant is not located at the plasma membrane, but shows overlapping expression with a marker protein of the lysosome. Mutation of the corresponding amino acid in murine Mct8 (Mct8L223R) displays a similar effect on cell surface expression and transport function as seen before for MCT8L291R. NaPB was able to correct the translocation defect of MCT8L291R/Mct8L223R and restored protein function by increasing T3 transport activity. Furthermore, we detected enhanced mRNA levels of wild-type and mutant MCT8/Mct8 after NaPB treatment. The increase in mRNA levels could be an explanation for the positive effect on protein expression and function detected for wild-type MCT8. CONCLUSION NaPB is not only suitable for the treatment of mutations leading to misfolding and protein degradation, but also for a mutant wrongly sorted inside a cell which is otherwise functional.
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Affiliation(s)
- Doreen Braun
- *Doreen Braun, Institut für Biochemie und Molekularbiologie, Medizinische Fakultät, Rheinische Friedrich-Wilhelms-Universität Bonn, Nussallee 11, DE–53115 Bonn (Germany),
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33
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Dunmore BJ, Yang X, Crosby A, Moore S, Long L, Huang C, Southwood M, Austin ED, Rana A, Upton PD, Morrell NW. 4PBA Restores Signaling of a Cysteine-substituted Mutant BMPR2 Receptor Found in Patients with Pulmonary Arterial Hypertension. Am J Respir Cell Mol Biol 2020; 63:160-171. [PMID: 32255665 DOI: 10.1165/rcmb.2019-0321oc] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Mutations in the gene encoding BMPR2 (bone morphogenetic protein type 2 receptor) are the major cause of heritable pulmonary arterial hypertension (PAH). Point mutations in the BMPR2 ligand-binding domain involving cysteine residues (such as C118W) are causative of PAH and predicted to cause protein misfolding. Using heterologous overexpression systems, we showed previously that these mutations lead to retention of BMPR2 in the endoplasmic reticulum but are partially rescued by chemical chaperones. Here, we sought to determine whether the chemical chaperone 4-phenylbutyrate (4PBA) restores BMPR2 signaling in primary cells and in a knockin mouse harboring a C118W mutation. First, we confirmed dysfunctional BMP signaling in dermal fibroblasts isolated from a family with PAH segregating the BMPR2 C118W mutation. After BMP4 treatment, the induction of downstream signaling targets (Smad1/5, ID1 [inhibitor of DNA binding 1], and ID2) was significantly reduced in C118W mutant cells. Treatment with 4PBA significantly rescued Smad1/5, ID1, and ID2 expression. Pulmonary artery smooth muscle cells isolated from the lungs of heterozygous mice harboring the Bmpr2 C118W mutation exhibited significantly increased proliferation. In the presence of 4PBA, hyperproliferation was dramatically reduced. Furthermore, in vivo, 4PBA treatment of Bmpr2 C118W mice partially rescued Bmpr2 expression, restored downstream signaling, and improved vascular remodeling. These findings demonstrate in primary cells and in a knockin mouse that the repurposed small-molecule chemical chaperone 4PBA might be a promising precision medicine approach to treat PAH in patients with specific subtypes of BMPR2 mutation involving cysteine substitutions in the ligand-binding domain.
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Affiliation(s)
- Benjamin J Dunmore
- Department of Medicine, University of Cambridge School of Clinical Medicine, Addenbrooke's and Royal Papworth Hospitals, Cambridge, United Kingdom
| | - XuDong Yang
- Department of Medicine, University of Cambridge School of Clinical Medicine, Addenbrooke's and Royal Papworth Hospitals, Cambridge, United Kingdom
| | - Alexi Crosby
- Department of Medicine, University of Cambridge School of Clinical Medicine, Addenbrooke's and Royal Papworth Hospitals, Cambridge, United Kingdom
| | - Stephen Moore
- Department of Medicine, University of Cambridge School of Clinical Medicine, Addenbrooke's and Royal Papworth Hospitals, Cambridge, United Kingdom
| | - Lu Long
- Department of Medicine, University of Cambridge School of Clinical Medicine, Addenbrooke's and Royal Papworth Hospitals, Cambridge, United Kingdom
| | - Christopher Huang
- Department of Medicine, University of Cambridge School of Clinical Medicine, Addenbrooke's and Royal Papworth Hospitals, Cambridge, United Kingdom
| | - Mark Southwood
- Pathology Research, Royal Papworth Hospital NHS Foundation Trust, Cambridge, United Kingdom; and
| | - Eric D Austin
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Amer Rana
- Department of Medicine, University of Cambridge School of Clinical Medicine, Addenbrooke's and Royal Papworth Hospitals, Cambridge, United Kingdom
| | - Paul D Upton
- Department of Medicine, University of Cambridge School of Clinical Medicine, Addenbrooke's and Royal Papworth Hospitals, Cambridge, United Kingdom
| | - Nicholas W Morrell
- Department of Medicine, University of Cambridge School of Clinical Medicine, Addenbrooke's and Royal Papworth Hospitals, Cambridge, United Kingdom
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Tanaka LY, Oliveira PVS, Laurindo FRM. Peri/Epicellular Thiol Oxidoreductases as Mediators of Extracellular Redox Signaling. Antioxid Redox Signal 2020; 33:280-307. [PMID: 31910038 DOI: 10.1089/ars.2019.8012] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Significance: Supracellular redox networks regulating cell-extracellular matrix (ECM) and organ system architecture merge with structural and functional (catalytic or allosteric) properties of disulfide bonds. This review addresses emerging evidence that exported thiol oxidoreductases (TORs), such as thioredoxin, protein disulfide isomerases (PDIs), quiescin sulfhydryl oxidases (QSOX)1, and peroxiredoxins, composing a peri/epicellular (pec)TOR pool, mediate relevant signaling. pecTOR functions depend mainly on kinetic and spatial regulation of thiol-disulfide exchange reactions governed by redox potentials, which are modulated by exported intracellular low-molecular-weight thiols, together conferring signal specificity. Recent Advances: pecTOR redox-modulates several targets including integrins, ECM proteins, surface molecules, and plasma components, although clear-cut documentation of direct effects is lacking in many cases. TOR catalytic pathways, displaying common patterns, culminate in substrate thiol reduction, oxidation, or isomerization. Peroxiredoxins act as redox/peroxide sensors, contrary to PDIs, which are likely substrate-targeted redox modulators. Emerging evidence suggests important pecTOR roles in patho(physio)logical processes, including blood coagulation, vascular remodeling, mechanosensing, endothelial function, immune responses, and inflammation. Critical Issues: Effects of pecPDIs supporting thrombosis/platelet activation have been well documented and reached the clinical arena. Roles of pecPDIA1 in vascular remodeling/mechanosensing are also emerging. Extracellular thioredoxin and pecPDIs redox-regulate immunoinflammation. Routes of TOR externalization remain elusive and appear to involve Golgi-independent routes. pecTORs are particularly accessible drug targets. Future Directions: Further understanding mechanisms of thiol redox reactions and developing assays for assessing pecTOR redox activities remain important research avenues. Also, addressing pecTORs as disease markers and achieving more efficient/specific drugs for pecTOR modulation are major perspectives for diagnostic/therapeutic improvements.
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Affiliation(s)
- Leonardo Y Tanaka
- Vascular Biology Laboratory, LIM-64 (Translational Cardiovascular Biology), Instituto do Coracao (InCor), Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo, Brazil
| | - Percillia V S Oliveira
- Vascular Biology Laboratory, LIM-64 (Translational Cardiovascular Biology), Instituto do Coracao (InCor), Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo, Brazil
| | - Francisco R M Laurindo
- Vascular Biology Laboratory, LIM-64 (Translational Cardiovascular Biology), Instituto do Coracao (InCor), Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo, Brazil
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35
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Ho N, Yap WS, Xu J, Wu H, Koh JH, Goh WWB, George B, Chong SC, Taubert S, Thibault G. Stress sensor Ire1 deploys a divergent transcriptional program in response to lipid bilayer stress. J Cell Biol 2020; 219:e201909165. [PMID: 32349127 PMCID: PMC7337508 DOI: 10.1083/jcb.201909165] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 02/26/2020] [Accepted: 04/07/2020] [Indexed: 12/11/2022] Open
Abstract
Membrane integrity at the endoplasmic reticulum (ER) is tightly regulated, and its disturbance is implicated in metabolic diseases. Using an engineered sensor that activates the unfolded protein response (UPR) exclusively when normal ER membrane lipid composition is compromised, we identified pathways beyond lipid metabolism that are necessary to maintain ER integrity in yeast and in C. elegans. To systematically validate yeast mutants that disrupt ER membrane homeostasis, we identified a lipid bilayer stress (LBS) sensor in the UPR transducer protein Ire1, located at the interface of the amphipathic and transmembrane helices. Furthermore, transcriptome and chromatin immunoprecipitation analyses pinpoint the UPR as a broad-spectrum compensatory response wherein LBS and proteotoxic stress deploy divergent transcriptional UPR programs. Together, these findings reveal the UPR program as the sum of two independent stress responses, an insight that could be exploited for future therapeutic intervention.
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Affiliation(s)
- Nurulain Ho
- Lipid Regulation and Cell Stress Group, School of Biological Sciences, Nanyang Technological University, Singapore
| | - Wei Sheng Yap
- Lipid Regulation and Cell Stress Group, School of Biological Sciences, Nanyang Technological University, Singapore
| | - Jiaming Xu
- Centre for Molecular Medicine and Therapeutics, British Columbia Children’s Hospital Research Institute, Department of Medical Genetics, University of British Columbia, Vancouver, Canada
| | - Haoxi Wu
- Lipid Regulation and Cell Stress Group, School of Biological Sciences, Nanyang Technological University, Singapore
| | - Jhee Hong Koh
- Lipid Regulation and Cell Stress Group, School of Biological Sciences, Nanyang Technological University, Singapore
| | - Wilson Wen Bin Goh
- Bio-Data Science and Education Research Group, School of Biological Sciences, Nanyang Technological University, Singapore
| | - Bhawana George
- Lipid Regulation and Cell Stress Group, School of Biological Sciences, Nanyang Technological University, Singapore
| | - Shu Chen Chong
- Lipid Regulation and Cell Stress Group, School of Biological Sciences, Nanyang Technological University, Singapore
| | - Stefan Taubert
- Centre for Molecular Medicine and Therapeutics, British Columbia Children’s Hospital Research Institute, Department of Medical Genetics, University of British Columbia, Vancouver, Canada
| | - Guillaume Thibault
- Lipid Regulation and Cell Stress Group, School of Biological Sciences, Nanyang Technological University, Singapore
- Institute of Molecular and Cell Biology, A*STAR, Singapore
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36
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Lopez S, Perez-Linero AM, Manzano-Lopez J, Sabido-Bozo S, Cortes-Gomez A, Rodriguez-Gallardo S, Aguilera-Romero A, Goder V, Muñiz M. Dual Independent Roles of the p24 Complex in Selectivity of Secretory Cargo Export from the Endoplasmic Reticulum. Cells 2020; 9:cells9051295. [PMID: 32456004 PMCID: PMC7291304 DOI: 10.3390/cells9051295] [Citation(s) in RCA: 2] [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: 02/24/2020] [Revised: 05/18/2020] [Accepted: 05/20/2020] [Indexed: 11/22/2022] Open
Abstract
The cellular mechanisms that ensure the selectivity and fidelity of secretory cargo protein transport from the endoplasmic reticulum (ER) to the Golgi are still not well understood. The p24 protein complex acts as a specific cargo receptor for GPI-anchored proteins by facilitating their ER exit through a specialized export pathway in yeast. In parallel, the p24 complex can also exit the ER using the general pathway that exports the rest of secretory proteins with their respective cargo receptors. Here, we show biochemically that the p24 complex associates at the ER with other cargo receptors in a COPII-dependent manner, forming high-molecular weight multireceptor complexes. Furthermore, live cell imaging analysis reveals that the p24 complex is required to retain in the ER secretory cargos when their specific receptors are absent. This requirement does not involve neither the unfolded protein response nor the retrograde transport from the Golgi. Our results suggest that, in addition to its role as a cargo receptor in the specialized GPI-anchored protein pathway, the p24 complex also plays an independent role in secretory cargo selectivity during its exit through the general ER export pathway, preventing the non-selective bulk flow of native secretory cargos. This mechanism would ensure receptor-regulated cargo transport, providing an additional layer of regulation of secretory cargo selectivity during ER export.
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Affiliation(s)
- Sergio Lopez
- Department of Cell Biology, University of Seville, 41012 Seville, Spain; (S.L.); (A.M.P.-L.); (J.M.-L.); (S.S.-B.); (A.C.-G.); (S.R.-G.); (A.A.-R.)
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, 41012 Seville, Spain
| | - Ana Maria Perez-Linero
- Department of Cell Biology, University of Seville, 41012 Seville, Spain; (S.L.); (A.M.P.-L.); (J.M.-L.); (S.S.-B.); (A.C.-G.); (S.R.-G.); (A.A.-R.)
| | - Javier Manzano-Lopez
- Department of Cell Biology, University of Seville, 41012 Seville, Spain; (S.L.); (A.M.P.-L.); (J.M.-L.); (S.S.-B.); (A.C.-G.); (S.R.-G.); (A.A.-R.)
| | - Susana Sabido-Bozo
- Department of Cell Biology, University of Seville, 41012 Seville, Spain; (S.L.); (A.M.P.-L.); (J.M.-L.); (S.S.-B.); (A.C.-G.); (S.R.-G.); (A.A.-R.)
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, 41012 Seville, Spain
| | - Alejandro Cortes-Gomez
- Department of Cell Biology, University of Seville, 41012 Seville, Spain; (S.L.); (A.M.P.-L.); (J.M.-L.); (S.S.-B.); (A.C.-G.); (S.R.-G.); (A.A.-R.)
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, 41012 Seville, Spain
| | - Sofia Rodriguez-Gallardo
- Department of Cell Biology, University of Seville, 41012 Seville, Spain; (S.L.); (A.M.P.-L.); (J.M.-L.); (S.S.-B.); (A.C.-G.); (S.R.-G.); (A.A.-R.)
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, 41012 Seville, Spain
| | - Auxiliadora Aguilera-Romero
- Department of Cell Biology, University of Seville, 41012 Seville, Spain; (S.L.); (A.M.P.-L.); (J.M.-L.); (S.S.-B.); (A.C.-G.); (S.R.-G.); (A.A.-R.)
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, 41012 Seville, Spain
| | - Veit Goder
- Department of Genetics, University of Seville, 41012 Seville, Spain;
| | - Manuel Muñiz
- Department of Cell Biology, University of Seville, 41012 Seville, Spain; (S.L.); (A.M.P.-L.); (J.M.-L.); (S.S.-B.); (A.C.-G.); (S.R.-G.); (A.A.-R.)
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, 41012 Seville, Spain
- Correspondence: ; Tel.: +34-954556529
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Phillips BP, Gomez-Navarro N, Miller EA. Protein quality control in the endoplasmic reticulum. Curr Opin Cell Biol 2020; 65:96-102. [PMID: 32408120 PMCID: PMC7588826 DOI: 10.1016/j.ceb.2020.04.002] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 03/02/2020] [Accepted: 04/02/2020] [Indexed: 11/30/2022]
Abstract
Misfolded and mistargeted proteins in the early secretory pathway present significant risks to the cell. A diverse and integrated network of quality control pathways protects the cell from these threats. We focus on the discovery of new mechanisms that contribute to this protective network. Biochemical and structural advances in endoplasmic reticulum targeting fidelity, and in the redistribution of mistargeted substrates are discussed. We further review new discoveries in quality control at the inner nuclear membrane in the context of orphaned subunits. We consider developments in our understanding of cargo selection for endoplasmic reticulum export. Conflicting data on quality control by cargo receptor proteins are discussed and we look to important future questions for the field.
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38
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Lu CL, Kim J. Consequences of mutations in the genes of the ER export machinery COPII in vertebrates. Cell Stress Chaperones 2020; 25:199-209. [PMID: 31970693 PMCID: PMC7058761 DOI: 10.1007/s12192-019-01062-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 11/14/2019] [Accepted: 12/13/2019] [Indexed: 11/28/2022] Open
Abstract
Coat protein complex II (COPII) plays an essential role in the export of cargo molecules such as secretory proteins, membrane proteins, and lipids from the endoplasmic reticulum (ER). In yeast, the COPII machinery is critical for cell viability as most COPII knockout mutants fail to survive. In mice and fish, homozygous knockout mutants of most COPII genes are embryonic lethal, reflecting the essentiality of the COPII machinery in the early stages of vertebrate development. In humans, COPII mutations, which are often hypomorphic, cause diseases having distinct clinical features. This is interesting as the fundamental cellular defect of these diseases, that is, failure of ER export, is similar. Analyses of humans and animals carrying COPII mutations have revealed clues to why a similar ER export defect can cause such different diseases. Previous reviews have focused mainly on the deficit of secretory or membrane proteins in the final destinations because of an ER export block. In this review, we also underscore the other consequence of the ER export block, namely ER stress triggered by the accumulation of cargo proteins in the ER.
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Affiliation(s)
- Chung-Ling Lu
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, 1800 Christensen Drive, Ames, IA, 50011, USA
| | - Jinoh Kim
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, 1800 Christensen Drive, Ames, IA, 50011, USA.
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Subramanian A, Capalbo A, Iyengar NR, Rizzo R, di Campli A, Di Martino R, Lo Monte M, Beccari AR, Yerudkar A, Del Vecchio C, Glielmo L, Turacchio G, Pirozzi M, Kim SG, Henklein P, Cancino J, Parashuraman S, Diviani D, Fanelli F, Sallese M, Luini A. Auto-regulation of Secretory Flux by Sensing and Responding to the Folded Cargo Protein Load in the Endoplasmic Reticulum. Cell 2020; 176:1461-1476.e23. [PMID: 30849374 DOI: 10.1016/j.cell.2019.01.035] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 08/30/2018] [Accepted: 01/23/2019] [Indexed: 11/19/2022]
Abstract
Maintaining the optimal performance of cell processes and organelles is the task of auto-regulatory systems. Here we describe an auto-regulatory device that helps to maintain homeostasis of the endoplasmic reticulum (ER) by adjusting the secretory flux to the cargo load. The cargo-recruiting subunit of the coatomer protein II (COPII) coat, Sec24, doubles as a sensor of folded cargo and, upon cargo binding, acts as a guanine nucleotide exchange factor to activate the signaling protein Gα12 at the ER exit sites (ERESs). This step, in turn, activates a complex signaling network that activates and coordinates the ER export machinery and attenuates proteins synthesis, thus preventing large fluctuations of folded and potentially active cargo that could be harmful to the cell or the organism. We call this mechanism AREX (autoregulation of ER export) and expect that its identification will aid our understanding of human physiology and diseases that develop from secretory dysfunction.
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Affiliation(s)
- Advait Subramanian
- Institute of Protein Biochemistry (IBP), Italian National Research Council (CNR), Napoli, Italy.
| | - Anita Capalbo
- Institute of Protein Biochemistry (IBP), Italian National Research Council (CNR), Napoli, Italy
| | - Namrata Ravi Iyengar
- Institute of Protein Biochemistry (IBP), Italian National Research Council (CNR), Napoli, Italy
| | - Riccardo Rizzo
- Institute of Protein Biochemistry (IBP), Italian National Research Council (CNR), Napoli, Italy
| | - Antonella di Campli
- Institute of Protein Biochemistry (IBP), Italian National Research Council (CNR), Napoli, Italy; Department of Medical, Oral and Biotechnological Sciences and CeSI-MeT, Center for Research on Ageing and Translational Medicine, "G. d'Annunzio" University of Chieti-Pescara, Chieti, Italy
| | - Rosaria Di Martino
- Institute of Protein Biochemistry (IBP), Italian National Research Council (CNR), Napoli, Italy
| | - Matteo Lo Monte
- Institute of Protein Biochemistry (IBP), Italian National Research Council (CNR), Napoli, Italy
| | - Andrea R Beccari
- Institute of Protein Biochemistry (IBP), Italian National Research Council (CNR), Napoli, Italy; Dompé Farmaceutici SpA, Milan, Italy
| | - Amol Yerudkar
- Department of Engineering, Universitá degli Studi del Sannio, Benevento, Italy
| | - Carmen Del Vecchio
- Department of Engineering, Universitá degli Studi del Sannio, Benevento, Italy
| | - Luigi Glielmo
- Department of Engineering, Universitá degli Studi del Sannio, Benevento, Italy
| | - Gabriele Turacchio
- Institute of Protein Biochemistry (IBP), Italian National Research Council (CNR), Napoli, Italy
| | - Marinella Pirozzi
- Institute of Protein Biochemistry (IBP), Italian National Research Council (CNR), Napoli, Italy
| | - Sang Geon Kim
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, South Korea
| | - Petra Henklein
- Institut fur Biochemie, Charite Universitätsmedizin, Berlin, Germany
| | - Jorge Cancino
- Centro de Biología Celular y Biomedicina (CEBICEM), Facultad de Medicina y Ciencia, Universidad San Sebastián, Lota 2465, Santiago 7510157, Chile
| | | | - Dario Diviani
- Université de Lausanne, Département de Pharmacologie et Toxicologie, Rue du Bugnon 27, 1011 Lausanne, Switzerland
| | - Francesca Fanelli
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Michele Sallese
- Department of Medical, Oral and Biotechnological Sciences and CeSI-MeT, Center for Research on Ageing and Translational Medicine, "G. d'Annunzio" University of Chieti-Pescara, Chieti, Italy
| | - Alberto Luini
- Institute of Protein Biochemistry (IBP), Italian National Research Council (CNR), Napoli, Italy.
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40
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Anelli T, Panina-Bordignon P. How to Avoid a No-Deal ER Exit. Cells 2019; 8:cells8091051. [PMID: 31500301 PMCID: PMC6769657 DOI: 10.3390/cells8091051] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2019] [Revised: 08/28/2019] [Accepted: 09/06/2019] [Indexed: 01/01/2023] Open
Abstract
Efficiency and fidelity of protein secretion are achieved thanks to the presence of different steps, located sequentially in time and space along the secretory compartment, controlling protein folding and maturation. After entering into the endoplasmic reticulum (ER), secretory proteins attain their native structure thanks to specific chaperones and enzymes. Only correctly folded molecules are allowed by quality control (QC) mechanisms to leave the ER and proceed to downstream compartments. Proteins that cannot fold properly are instead retained in the ER to be finally destined to proteasomal degradation. Exiting from the ER requires, in most cases, the use of coated vesicles, departing at the ER exit sites, which will fuse with the Golgi compartment, thus releasing their cargoes. Protein accumulation in the ER can be caused by a too stringent QC or by ineffective transport: these situations could be deleterious for the organism, due to the loss of the secreted protein, and to the cell itself, because of abnormal increase of protein concentration in the ER. In both cases, diseases can arise. In this review, we will describe the pathophysiology of protein folding and transport between the ER and the Golgi compartment.
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Affiliation(s)
- Tiziana Anelli
- Vita-Salute San Raffaele University, 20132 Milan, Italy.
- Division of Genetics and Cell Biology, IRCCS Ospedale San Raffaele, 20132 Milan, Italy.
| | - Paola Panina-Bordignon
- Vita-Salute San Raffaele University, 20132 Milan, Italy.
- Division of Neuroscience, IRCCS Ospedale San Raffaele, 20132 Milan, Italy.
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41
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Peotter J, Kasberg W, Pustova I, Audhya A. COPII-mediated trafficking at the ER/ERGIC interface. Traffic 2019; 20:491-503. [PMID: 31059169 PMCID: PMC6640837 DOI: 10.1111/tra.12654] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 04/25/2019] [Accepted: 05/02/2019] [Indexed: 12/16/2022]
Abstract
Coat proteins play multiple roles in the life cycle of a membrane-bound transport intermediate, functioning in lipid bilayer remodeling, cargo selection and targeting to an acceptor compartment. The Coat Protein complex II (COPII) coat is known to act in each of these capacities, but recent work highlights the necessity for numerous accessory factors at all stages of transport carrier existence. Here, we review recent findings that highlight the roles of COPII and its regulators in the biogenesis of tubular COPII-coated carriers in mammalian cells that enable cargo transport between the endoplasmic reticulum and ER-Golgi intermediate compartments, the first step in a series of trafficking events that ultimately allows for the distribution of biosynthetic secretory cargoes throughout the entire endomembrane system.
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Affiliation(s)
- Jennifer Peotter
- Department of Biomolecular Chemistry, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin
| | - William Kasberg
- Department of Biomolecular Chemistry, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin
| | - Iryna Pustova
- Department of Biomolecular Chemistry, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin
| | - Anjon Audhya
- Department of Biomolecular Chemistry, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin
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42
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Di S, Fan C, Ma Z, Li M, Guo K, Han D, Li X, Mu D, Yan X. PERK/eIF-2α/CHOP Pathway Dependent ROS Generation Mediates Butein-induced Non-small-cell Lung Cancer Apoptosis and G2/M Phase Arrest. Int J Biol Sci 2019; 15:1637-1653. [PMID: 31360107 PMCID: PMC6643215 DOI: 10.7150/ijbs.33790] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Accepted: 05/04/2019] [Indexed: 12/12/2022] Open
Abstract
Butein, a member of the chalcone family, is a potent anticarcinogen against multiple cancers, but its specific anti-NSCLC mechanism remains unknown. The present study examined the effects of butein treatment on NSCLC cell lines and NSCLC xenografts. Butein markedly decreased NSCLC cell viability; inhibited cell adhesion, migration, invasion, and colony forming ability; and induced cell apoptosis and G2/M phase arrest in NSCLC cells. Moreover, butein significantly inhibited PC-9 xenograft growth. Both in vivo and in vitro studies verified that butein exerted anti-NSCLC effect through activating endoplasmic reticulum (ER) stress-dependent reactive oxygen species (ROS) generation. These pro-apoptotic effects were reversed by the use of 4- phenylbutyric acid (4-PBA), CHOP siRNA, N-acetyl-L-cysteine (NAC) and Z-VAD-FMK (z-VAD) in vitro. Moreover, inhibition of ER stress markedly reduced ROS generation. In addition, in vivo studies further confirmed that inhibition of ER stress or oxidative stress partially abolished the butein-induced inhibition of tumor growth. Therefore, butein is a potential therapeutic agent for NSCLC, and its anticarcinogenic action might be mediated by ER stress-dependent ROS generation and the apoptosis pathway.
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Affiliation(s)
- Shouyin Di
- Department of Thoracic Surgery, Tangdu Hospital, The Fourth Military Medical University, 1 Xinsi Road, Xi'an 710038, China
| | - Chongxi Fan
- Department of Biomedical Engineering, The Fourth Military Medical University, 169 Changle West Road, Xi'an 710032, China
| | - Zhiqiang Ma
- Department of Thoracic Surgery, Tangdu Hospital, The Fourth Military Medical University, 1 Xinsi Road, Xi'an 710038, China
| | - Mingyang Li
- Department of Pathology, Xijing Hospital, The Fourth Military Medical University, 127 Changle West Road, Xi'an 710032, China
| | - Kai Guo
- Department of Thoracic Surgery, Tangdu Hospital, The Fourth Military Medical University, 1 Xinsi Road, Xi'an 710038, China
| | - Donghui Han
- Department of Urology, Xijing Hospital, The Fourth Military Medical University, 127 Changle West Road, Xi'an 710032, China
| | - Xiaofei Li
- Department of Thoracic Surgery, Tangdu Hospital, The Fourth Military Medical University, 1 Xinsi Road, Xi'an 710038, China
| | - Deguang Mu
- Department of Respiratory Medicine, Zhejiang Provincial People's Hospital, Hangzhou Medicine College, 158 Shangtang Road, Hangzhou 310014, China
| | - Xiaolong Yan
- Department of Thoracic Surgery, Tangdu Hospital, The Fourth Military Medical University, 1 Xinsi Road, Xi'an 710038, China
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43
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Dickinson MS, Anderson LN, Webb-Robertson BJM, Hansen JR, Smith RD, Wright AT, Hybiske K. Proximity-dependent proteomics of the Chlamydia trachomatis inclusion membrane reveals functional interactions with endoplasmic reticulum exit sites. PLoS Pathog 2019; 15:e1007698. [PMID: 30943267 PMCID: PMC6464245 DOI: 10.1371/journal.ppat.1007698] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 04/15/2019] [Accepted: 03/12/2019] [Indexed: 11/18/2022] Open
Abstract
Chlamydia trachomatis is the most common cause of bacterial sexually transmitted infection, responsible for millions of infections each year. Despite this high prevalence, the elucidation of the molecular mechanisms of Chlamydia pathogenesis has been difficult due to limitations in genetic tools and its intracellular developmental cycle. Within a host epithelial cell, chlamydiae replicate within a vacuole called the inclusion. Many Chlamydia-host interactions are thought to be mediated by the Inc family of type III secreted proteins that are anchored in the inclusion membrane, but their array of host targets are largely unknown. To investigate how the inclusion membrane proteome changes over the course of an infected cell, we have adapted the APEX2 system of proximity-dependent biotinylation. APEX2 is capable of specifically labeling proteins within a 20 nm radius in living cells. We transformed C. trachomatis to express the enzyme APEX2 fused to known inclusion membrane proteins, allowing biotinylation and purification of inclusion-associated proteins. Using quantitative mass spectrometry against APEX2 labeled samples, we identified over 400 proteins associated with the inclusion membrane at early, middle, and late stages of epithelial cell infection. This system was sensitive enough to detect inclusion interacting proteins early in the developmental cycle, at 8 hours post infection, a previously intractable time point. Mass spectrometry analysis revealed a novel, early association between C. trachomatis inclusions and endoplasmic reticulum exit sites (ERES), functional regions of the ER where COPII-coated vesicles originate. Pharmacological and genetic disruption of ERES function severely restricted early chlamydial growth and the development of infectious progeny. APEX2 is therefore a powerful in situ approach for identifying critical protein interactions on the membranes of pathogen-containing vacuoles. Furthermore, the data derived from proteomic mapping of Chlamydia inclusions has illuminated an important functional role for ERES in promoting chlamydial developmental growth.
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Affiliation(s)
- Mary S. Dickinson
- Department of Global Health, Graduate Program in Pathobiology, University of Washington, Seattle, WA, United States of America
- Department of Medicine, Division of Allergy and Infectious Diseases, Center for Emerging and Reemerging Infectious Disease (CERID), University of Washington, Seattle, WA, United States of America
| | - Lindsey N. Anderson
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, United States of America
| | | | - Joshua R. Hansen
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, United States of America
| | - Richard D. Smith
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, United States of America
| | - Aaron T. Wright
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, United States of America
- The Gene and Linda Voiland College of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA, United States of America
| | - Kevin Hybiske
- Department of Global Health, Graduate Program in Pathobiology, University of Washington, Seattle, WA, United States of America
- Department of Medicine, Division of Allergy and Infectious Diseases, Center for Emerging and Reemerging Infectious Disease (CERID), University of Washington, Seattle, WA, United States of America
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44
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Adolf F, Rhiel M, Hessling B, Gao Q, Hellwig A, Béthune J, Wieland FT. Proteomic Profiling of Mammalian COPII and COPI Vesicles. Cell Rep 2019; 26:250-265.e5. [DOI: 10.1016/j.celrep.2018.12.041] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 09/08/2018] [Accepted: 12/10/2018] [Indexed: 12/26/2022] Open
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45
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Jiang X, Fang G, Dong L, Jin P, Ding L, Zhang H, Fan J, Mao S, Fan X, Gong Y, Wang Y. Chemical chaperone 4-phenylbutyric acid alleviates the aggregation of human familial pulmonary fibrosis-related mutant SP-A2 protein in part through effects on GRP78. Biochim Biophys Acta Mol Basis Dis 2018; 1864:3546-3557. [PMID: 30293573 DOI: 10.1016/j.bbadis.2018.08.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 08/06/2018] [Accepted: 08/07/2018] [Indexed: 12/13/2022]
Abstract
G231V and F198S mutations in surfactant protein A2 (SP-A2) are associated with familial pulmonary fibrosis. These mutations cause defects in dimer/trimer assembly, trafficking, and secretion, as well as cause mutant protein aggregation. We investigated the effects and mechanisms of chemical chaperones on the cellular and biochemical properties of mutant SP-A2. Chemical chaperones, including 4-phenyl butyric acid (4-PBA), could enhance secretion and decrease intracellular aggregation of mutant SP-A2 in a dose-dependent manner. Interestingly, increased levels of aggregated mutant SP-A2, resulting from MG-132-mediated proteasome inhibition, could also be alleviated by 4-PBA. 4-PBA treatment reduced the degradation of mutant SP-A2 to chymotrypsin digestion in CHO-K1 cells and up-regulated GRP78 (BiP) expression. Overexpression of GRP78 in SP-A2 G231V- or F198S-expressing cells reduced, whereas shRNA-mediated knockdown of GRP78 enhanced aggregation of mutant SP-A2, suggesting that GRP78 regulates aggregation of mutant SP-A2. Together, these data indicate chemical chaperone 4-PBA and upregulation of GRP78 can alleviate aggregation to stabilize and facilitate secretion of mutant SP-A2. The up-regulation expression of GRP78 might partially contribute to the aggregate-alleviating effect of 4-PBA.
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Affiliation(s)
- Xu Jiang
- Institute of Hypoxia Medicine, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Guodong Fang
- Department of Pathology, Shaanxi Provincial People's Hospital, The Third Affiliated Hospital of Xi'an JiaoTong University, Xi'an 710068, Shaanxi, China
| | - Li Dong
- Department of Respiratory Medicine, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325015, Zhejiang, China
| | - Peifeng Jin
- Department of Cardiothoracic Surgery, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325015, Zhejiang, China
| | - Lu Ding
- Institute of Hypoxia Medicine, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Haizeng Zhang
- Institute of Hypoxia Medicine, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Junming Fan
- Institute of Hypoxia Medicine, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Sunzhong Mao
- Institute of Hypoxia Medicine, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Xiaofang Fan
- Institute of Hypoxia Medicine, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Yongsheng Gong
- Institute of Hypoxia Medicine, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, China.
| | - Yongyu Wang
- Institute of Hypoxia Medicine, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, China.
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46
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Aridor M. COPII gets in shape: Lessons derived from morphological aspects of early secretion. Traffic 2018; 19:823-839. [DOI: 10.1111/tra.12603] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Revised: 06/26/2018] [Accepted: 07/04/2018] [Indexed: 12/13/2022]
Affiliation(s)
- Meir Aridor
- Department of Cell Biology; University of Pittsburgh School of Medicine; Pittsburgh Pennsylvania
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Kasture A, Stockner T, Freissmuth M, Sucic S. An unfolding story: Small molecules remedy misfolded monoamine transporters. Int J Biochem Cell Biol 2017; 92:1-5. [PMID: 28890376 PMCID: PMC5679356 DOI: 10.1016/j.biocel.2017.09.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 08/24/2017] [Accepted: 09/06/2017] [Indexed: 12/16/2022]
Abstract
The key role of monoamine transporters is to take up neurotransmitters from the synaptic cleft and rapidly terminate neurotransmission. Monoamine transporters begin their journey by folding in the endoplasmic reticulum. Upon achieving their natively-folded state, the oligomerized transporters engage the coat protein complex II machinery and exit the endoplasmic reticulum compartment in a concentrative fashion. The transporters are subsequently sorted in the endoplasmic reticulum-Golgi intermediate complex and the Golgi apparatus, prior to reaching their pivotal site of action at the plasma membrane. Stringent quality-control mechanisms ensure that only the correctly-folded protein cargo departs the endoplasmic reticulum. Genetic point mutations in the coding sequences of monoamine transporters can trigger severe physiologic deficiencies by inducing folding defects. Protein misfolding precludes the delivery of functional monoamine transporters to the cell surface. Chemical- and/or pharmacological-chaperone molecules, which facilitate folding, have proven effective in restoring the activity of several misfolded pathological variants of monoamine transporters.
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Affiliation(s)
- Ameya Kasture
- Institute of Pharmacology, Center of Physiology and Pharmacology and Gaston H. Glock Research Laboratories for Exploratory Drug Development, Medical University of Vienna, Austria
| | - Thomas Stockner
- Institute of Pharmacology, Center of Physiology and Pharmacology and Gaston H. Glock Research Laboratories for Exploratory Drug Development, Medical University of Vienna, Austria
| | - Michael Freissmuth
- Institute of Pharmacology, Center of Physiology and Pharmacology and Gaston H. Glock Research Laboratories for Exploratory Drug Development, Medical University of Vienna, Austria
| | - Sonja Sucic
- Institute of Pharmacology, Center of Physiology and Pharmacology and Gaston H. Glock Research Laboratories for Exploratory Drug Development, Medical University of Vienna, Austria.
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