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Choi JT, Choi Y, Lee Y, Lee SH, Kang S, Lee KT, Bahn YS. The hybrid RAVE complex plays V-ATPase-dependent and -independent pathobiological roles in Cryptococcus neoformans. PLoS Pathog 2023; 19:e1011721. [PMID: 37812645 PMCID: PMC10586682 DOI: 10.1371/journal.ppat.1011721] [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: 05/09/2023] [Revised: 10/19/2023] [Accepted: 09/29/2023] [Indexed: 10/11/2023] Open
Abstract
V-ATPase, which comprises 13-14 subunits, is essential for pH homeostasis in all eukaryotes, but its proper function requires a regulator to assemble its subunits. While RAVE (regulator of H+-ATPase of vacuolar and endosomal membranes) and Raboconnectin-3 complexes assemble V-ATPase subunits in Saccharomyces cerevisiae and humans, respectively, the function of the RAVE complex in fungal pathogens remains largely unknown. In this study, we identified two RAVE complex components, Rav1 and Wdr1, in the fungal meningitis pathogen Cryptococcus neoformans, and analyzed their roles. Rav1 and Wdr1 are orthologous to yeast RAVE and human Rabconnectin-3 counterparts, respectively, forming the hybrid RAVE (hRAVE) complex. Deletion of RAV1 caused severe defects in growth, cell cycle control, morphogenesis, sexual development, stress responses, and virulence factor production, while the deletion of WDR1 resulted in similar but modest changes, suggesting that Rav1 and Wdr1 play central and accessary roles, respectively. Proteomics analysis confirmed that Wdr1 was one of the Rav1-interacting proteins. Although the hRAVE complex generally has V-ATPase-dependent functions, it also has some V-ATPase-independent roles, suggesting a unique role beyond conventional intracellular pH regulation in C. neoformans. The hRAVE complex played a critical role in the pathogenicity of C. neoformans, and RAV1 deletion attenuated virulence and impaired blood-brain barrier crossing ability. This study provides comprehensive insights into the pathobiological roles of the fungal RAVE complex and suggests a novel therapeutic strategy for controlling cryptococcosis.
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Affiliation(s)
- Jin-Tae Choi
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, Korea
| | - Yeseul Choi
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, Korea
| | - Yujin Lee
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, Korea
| | - Seung-Heon Lee
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, Korea
| | - Seun Kang
- Korea Zoonosis Research Institute, Jeonbuk National University, Jeonbuk, Republic of Korea
| | - Kyung-Tae Lee
- Korea Zoonosis Research Institute, Jeonbuk National University, Jeonbuk, Republic of Korea
| | - Yong-Sun Bahn
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, Korea
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2
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Sastri KT, Gupta NV, M S, Chakraborty S, Kumar H, Chand P, Balamuralidhara V, Gowda D. Nanocarrier facilitated drug delivery to the brain through intranasal route: A promising approach to transcend bio-obstacles and alleviate neurodegenerative conditions. J Drug Deliv Sci Technol 2022. [DOI: 10.1016/j.jddst.2022.103656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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3
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Ghosh A, Kar PK, Gautam A, Gupta R, Singh R, Chakravarti R, Ravichandiran V, Ghosh Dastidar S, Ghosh D, Roy S. An insight into SARS-CoV-2 structure, pathogenesis, target hunting for drug development and vaccine initiatives. RSC Med Chem 2022; 13:647-675. [PMID: 35814927 PMCID: PMC9215161 DOI: 10.1039/d2md00009a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 01/20/2022] [Indexed: 01/27/2023] Open
Abstract
SARS-CoV-2, the virus responsible for the COVID-19 pandemic, has been confirmed to be a new coronavirus having 79% and 50% similarity with SARS-CoV and MERS-CoV, respectively. For a better understanding of the features of the new virus SARS-CoV-2, we have discussed a possible correlation between some unique features of the genome of SARS-CoV-2 in relation to pathogenesis. We have also reviewed structural druggable viral and host targets for possible clinical application if any, as cases of reinfection and compromised protection have been noticed due to the emergence of new variants with increased infectivity even after vaccination. We have also discussed the types of vaccines that are being developed against SARS-CoV-2. In this review, we have tried to give a brief overview of the fundamental factors of COVID-19 research like basic virology, virus variants and the newly emerging techniques that can be applied to develop advanced treatment strategies for the management of COVID-19 disease.
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Affiliation(s)
- Arijit Ghosh
- Department of Natural Products, National Institute of Pharmaceutical Education and Research Kolkata India
- Department of Chemistry, University of Calcutta Kolkata India
- Netaji Subhas Chandra Bose Cancer Research institute 3081, Nayabad Kolkata-700094 India
| | - Paritosh K Kar
- Foundation on Tropical Diseases & Health Research Development, A Mission on Charitable Health Care Unit Balichak CT, Paschim Medinipur West Bengal 721 124 India
| | - Anupam Gautam
- Institute for Bioinformatics and Medical Informatics, University of Tübingen Sand 14 72076 Tübingen Germany
- International Max Planck Research School "From Molecules to Organisms", Max Planck Institute for Biology Tübingen Max-Planck-Ring 5 72076 Tübingen Germany
| | - Rahul Gupta
- Infectious Diseases and Immunology Division, CSIR-Indian Institute of Chemical Biology Kolkata India
| | - Rajveer Singh
- Department of Natural Products, National Institute of Pharmaceutical Education and Research Kolkata India
| | - Rudra Chakravarti
- Department of Natural Products, National Institute of Pharmaceutical Education and Research Kolkata India
| | - Velayutham Ravichandiran
- Department of Natural Products, National Institute of Pharmaceutical Education and Research Kolkata India
| | | | - Dipanjan Ghosh
- Department of Natural Products, National Institute of Pharmaceutical Education and Research Kolkata India
| | - Syamal Roy
- Infectious Diseases and Immunology Division, CSIR-Indian Institute of Chemical Biology Kolkata India
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4
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Shin J, Nile A, Oh JW. Role of adaptin protein complexes in intracellular trafficking and their impact on diseases. Bioengineered 2021; 12:8259-8278. [PMID: 34565296 PMCID: PMC8806629 DOI: 10.1080/21655979.2021.1982846] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Revised: 09/15/2021] [Accepted: 09/15/2021] [Indexed: 02/07/2023] Open
Abstract
Adaptin proteins (APs) play a crucial role in intracellular cell trafficking. The 'classical' role of APs is carried out by AP1‒3, which bind to clathrin, cargo, and accessory proteins. Accordingly, AP1-3 are crucial for both vesicle formation and sorting. All APs consist of four subunits that are indispensable for their functions. In fact, based on studies using cells, model organism knockdown/knock-out, and human variants, each subunit plays crucial roles and contributes to the specificity of each AP. These studies also revealed that the sorting and intracellular trafficking function of AP can exert varying effects on pathology by controlling features such as cell development, signal transduction related to the apoptosis and proliferation pathways in cancer cells, organelle integrity, receptor presentation, and viral infection. Although the roles and functions of AP1‒3 are relatively well studied, the functions of the less abundant and more recently identified APs, AP4 and AP5, are still to be investigated. Further studies on these APs may enable a better understanding and targeting of specific diseases.APs known or suggested locations and functions.
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Affiliation(s)
- Juhyun Shin
- Department of Stem Cell and Regenerative Biotechnology and Animal Resources Research Center, Konkuk University, Seoul, Republic of Korea
| | - Arti Nile
- Department of Stem Cell and Regenerative Biotechnology and Animal Resources Research Center, Konkuk University, Seoul, Republic of Korea
| | - Jae-Wook Oh
- Department of Stem Cell and Regenerative Biotechnology and Animal Resources Research Center, Konkuk University, Seoul, Republic of Korea
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5
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Roles of Endocytic Processes and Early Endosomes on Focal Adhesion Dynamics in MDA-MB-231 Cells. Rep Biochem Mol Biol 2021; 10:145-155. [PMID: 34604404 DOI: 10.52547/rbmb.10.2.145] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 04/22/2021] [Indexed: 01/02/2023]
Abstract
Background Focal adhesion (FA) play a critical role in many biological processes which include cell survival and cell migration. They serve as cellular anchor, allowing cells to stay attached to the extracellular matrix (ECM), and can also regulate cellular transduction. Previously, it has been suggested that vesicles such as endosomes could interact directly with FA or be implicated in their turnover. In this study, we investigated whether there is a relationship between FA and the early endocytic machinery in MDA-MB-231 cells. Methods In this study, cell culture, transfection, time laps confocal microscopies, immunocytochemistry, western blotting, Cell fractionation and immunoprecipitation techniques were performed. Results Cells acutely treated with Dynasore, an inhibitor of dynamin, or with Pitstop 2, an inhibitor of clathryn-dependent endocytosis showed a reduction in the expression of early endosome biomarkers such as Rab5 and EEA1. Additionally, cells treated with these endocytic inhibitors exhibited an increase number and size of FA, as well as an increase FA turnover duration. This data was consistent with the reduction of the speed of cell migration. We demonstrated that Rab5- and EEA1-positive early endosomes were found to be colocalized with internalized FA. Conclusion The present study suggests that there is a link between FA and early endosome markers, which indicates that the early endosomes may be involved in FA dynamics.
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Kadir SR, Lilja A, Gunn N, Strong C, Hughes RT, Bailey BJ, Rae J, Parton RG, McGhee J. Nanoscape, a data-driven 3D real-time interactive virtual cell environment. eLife 2021; 10:64047. [PMID: 34191720 PMCID: PMC8245131 DOI: 10.7554/elife.64047] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 06/04/2021] [Indexed: 12/15/2022] Open
Abstract
Our understanding of cellular and structural biology has reached unprecedented levels of detail, and computer visualisation techniques can be used to create three-dimensional (3D) representations of cells and their environment that are useful in both teaching and research. However, extracting and integrating the relevant scientific data, and then presenting them in an effective way, can pose substantial computational and aesthetic challenges. Here we report how computer artists, experts in computer graphics and cell biologists have collaborated to produce a tool called Nanoscape that allows users to explore and interact with 3D representations of cells and their environment that are both scientifically accurate and visually appealing. We believe that using Nanoscape as an immersive learning application will lead to an improved understanding of the complexities of cellular scales, densities and interactions compared with traditional learning modalities.
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Affiliation(s)
- Shereen R Kadir
- 3D Visualisation Aesthetics Lab, School of Art and Design, and the ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, University of New South Wales, Sydney, Australia
| | - Andrew Lilja
- 3D Visualisation Aesthetics Lab, School of Art and Design, and the ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, University of New South Wales, Sydney, Australia
| | - Nick Gunn
- 3D Visualisation Aesthetics Lab, School of Art and Design, and the ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, University of New South Wales, Sydney, Australia
| | - Campbell Strong
- 3D Visualisation Aesthetics Lab, School of Art and Design, and the ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, University of New South Wales, Sydney, Australia
| | - Rowan T Hughes
- 3D Visualisation Aesthetics Lab, School of Art and Design, and the ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, University of New South Wales, Sydney, Australia
| | - Benjamin J Bailey
- 3D Visualisation Aesthetics Lab, School of Art and Design, and the ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, University of New South Wales, Sydney, Australia
| | - James Rae
- Institute for Molecular Bioscience, ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, and Centre for Microscopy and Microanalysis, University of Queensland, Brisbane, Australia
| | - Robert G Parton
- Institute for Molecular Bioscience, ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, and Centre for Microscopy and Microanalysis, University of Queensland, Brisbane, Australia
| | - John McGhee
- 3D Visualisation Aesthetics Lab, School of Art and Design, and the ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, University of New South Wales, Sydney, Australia
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7
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Schmidt-Arras D, Rose-John S. Endosomes as Signaling Platforms for IL-6 Family Cytokine Receptors. Front Cell Dev Biol 2021; 9:688314. [PMID: 34141712 PMCID: PMC8204807 DOI: 10.3389/fcell.2021.688314] [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: 03/30/2021] [Accepted: 04/28/2021] [Indexed: 12/12/2022] Open
Abstract
Interleukin-6 (IL-6) is the name-giving cytokine of a family of eleven members, including IL-6, CNTF, LIF, and IL-27. IL-6 was first recognized as a B-cell stimulating factor but we now know that the cytokine plays a pivotal role in the orchestration of inflammatory processes as well as in inflammation associated cancer. Moreover, IL-6 is involved in metabolic regulation and it has been shown to be involved in major neural activities such as neuroprotection, which can help to repair and to reduce brain damage. Receptor complexes of all members formed at the plasma membrane contain one or two molecules of the signaling receptor subunit GP130 and the mechanisms of signal transduction are well understood. IL-6 type cytokines can also signal from endomembranes, in particular the endosome, and situations have been reported in which endocytosis of receptor complexes are a prerequisite of intracellular signaling. Moreover, pathogenic GP130 variants were shown to interfere with spatial activation of downstream signals. We here summarize the molecular mechanisms underlying spatial regulation of IL-6 family cytokine signaling and discuss its relevance for pathogenic processes.
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Affiliation(s)
- Dirk Schmidt-Arras
- Institute of Biochemistry, Christian-Albrechts-University Kiel, Kiel, Germany
| | - Stefan Rose-John
- Institute of Biochemistry, Christian-Albrechts-University Kiel, Kiel, Germany
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8
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Li G, Su B, Fu P, Bai Y, Ding G, Li D, Wang J, Yang G, Chu B. NPC1-regulated dynamic of clathrin-coated pits is essential for viral entry. SCIENCE CHINA-LIFE SCIENCES 2021; 65:341-361. [PMID: 34047913 PMCID: PMC8160554 DOI: 10.1007/s11427-021-1929-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Accepted: 04/12/2021] [Indexed: 12/21/2022]
Abstract
Viruses utilize cellular lipids and manipulate host lipid metabolism to ensure their replication and spread. Therefore, the identification of lipids and metabolic pathways that are suitable targets for antiviral development is crucial. Using a library of compounds targeting host lipid metabolic factors and testing them for their ability to block pseudorabies virus (PRV) and vesicular stomatitis virus (VSV) infection, we found that U18666A, a specific inhibitor of Niemann-Pick C1 (NPC1), is highly potent in suppressing the entry of diverse viruses including pseudotyped severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). NPC1 deficiency markedly attenuates viral growth by decreasing cholesterol abundance in the plasma membrane, thereby inhibiting the dynamics of clathrin-coated pits (CCPs), which are indispensable for clathrin-mediated endocytosis. Significantly, exogenous cholesterol can complement the dynamics of CCPs, leading to efficient viral entry and infectivity. Administration of U18666A improves the survival and pathology of PRV- and influenza A virus-infected mice. Thus, our studies demonstrate a unique mechanism by which NPC1 inhibition achieves broad antiviral activity, indicating a potential new therapeutic strategy against SARS-CoV-2, as well as other emerging viruses.
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Affiliation(s)
- Guoli Li
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450046, China
- Key Laboratory of Animal Biochemistry and Nutrition, Ministry of Agriculture and Rural Affairs of the People's Republic of China, Zhengzhou, 450046, China
| | - Bingqian Su
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450046, China
- Key Laboratory of Animal Biochemistry and Nutrition, Ministry of Agriculture and Rural Affairs of the People's Republic of China, Zhengzhou, 450046, China
| | - Pengfei Fu
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450046, China
- Key Laboratory of Animal Biochemistry and Nutrition, Ministry of Agriculture and Rural Affairs of the People's Republic of China, Zhengzhou, 450046, China
| | - Yilin Bai
- College of Veterinary Medicine, Northwest A&F University, Yangling, 712100, China
| | - Guangxu Ding
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450046, China
- Key Laboratory of Animal Biochemistry and Nutrition, Ministry of Agriculture and Rural Affairs of the People's Republic of China, Zhengzhou, 450046, China
| | - Dahua Li
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450046, China
- Key Laboratory of Animal Biochemistry and Nutrition, Ministry of Agriculture and Rural Affairs of the People's Republic of China, Zhengzhou, 450046, China
| | - Jiang Wang
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450046, China
- Key Laboratory of Animal Biochemistry and Nutrition, Ministry of Agriculture and Rural Affairs of the People's Republic of China, Zhengzhou, 450046, China
- International Joint Research Center of National Animal Immunology, Henan Agricultural University, Zhengzhou, 450046, China
| | - Guoyu Yang
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450046, China.
- Key Laboratory of Animal Biochemistry and Nutrition, Ministry of Agriculture and Rural Affairs of the People's Republic of China, Zhengzhou, 450046, China.
- International Joint Research Center of National Animal Immunology, Henan Agricultural University, Zhengzhou, 450046, China.
| | - Beibei Chu
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450046, China.
- Key Laboratory of Animal Biochemistry and Nutrition, Ministry of Agriculture and Rural Affairs of the People's Republic of China, Zhengzhou, 450046, China.
- International Joint Research Center of National Animal Immunology, Henan Agricultural University, Zhengzhou, 450046, China.
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9
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Djakbarova U, Madraki Y, Chan ET, Kural C. Dynamic interplay between cell membrane tension and clathrin-mediated endocytosis. Biol Cell 2021; 113:344-373. [PMID: 33788963 DOI: 10.1111/boc.202000110] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 03/08/2021] [Accepted: 03/19/2021] [Indexed: 12/26/2022]
Abstract
Deformability of the plasma membrane, the outermost surface of metazoan cells, allows cells to be dynamic, mobile and flexible. Factors that affect this deformability, such as tension on the membrane, can regulate a myriad of cellular functions, including membrane resealing, cell motility, polarisation, shape maintenance, membrane area control and endocytic vesicle trafficking. This review focuses on mechanoregulation of clathrin-mediated endocytosis (CME). We first delineate the origins of cell membrane tension and the factors that yield to its spatial and temporal fluctuations within cells. We then review the recent literature demonstrating that tension on the membrane is a fast-acting and reversible regulator of CME. Finally, we discuss tension-based regulation of endocytic clathrin coat formation during physiological processes.
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Affiliation(s)
| | - Yasaman Madraki
- Department of Physics, The Ohio State University, Columbus, OH, 43210, USA
| | - Emily T Chan
- Interdisciplinary Biophysics Graduate Program, The Ohio State University, Columbus, OH, 43210, USA.,Molecular Biophysics Training Program, The Ohio State University, Columbus, OH, 43210, USA
| | - Cömert Kural
- Department of Physics, The Ohio State University, Columbus, OH, 43210, USA.,Interdisciplinary Biophysics Graduate Program, The Ohio State University, Columbus, OH, 43210, USA
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10
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Camblor-Perujo S, Kononenko NL. Brain-specific functions of the endocytic machinery. FEBS J 2021; 289:2219-2246. [PMID: 33896112 DOI: 10.1111/febs.15897] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 03/29/2021] [Indexed: 12/12/2022]
Abstract
Endocytosis is an essential cellular process required for multiple physiological functions, including communication with the extracellular environment, nutrient uptake, and signaling by the cell surface receptors. In a broad sense, endocytosis is accomplished through either constitutive or ligand-induced invagination of the plasma membrane, which results in the formation of the plasma membrane-retrieved endocytic vesicles, which can either be sent for degradation to the lysosomes or recycled back to the PM. This additional function of endocytosis in membrane retrieval has been adopted by excitable cells, such as neurons, for membrane equilibrium maintenance at synapses. The last two decades were especially productive with respect to the identification of brain-specific functions of the endocytic machinery, which additionally include but not limited to regulation of neuronal differentiation and migration, maintenance of neuron morphology and synaptic plasticity, and prevention of neurotoxic aggregates spreading. In this review, we highlight the current knowledge of brain-specific functions of endocytic machinery with a specific focus on three brain cell types, neuronal progenitor cells, neurons, and glial cells.
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Affiliation(s)
| | - Natalia L Kononenko
- CECAD Cluster of Excellence, University of Cologne, Germany.,Center for Physiology & Pathophysiology, Medical Faculty, University of Cologne, Germany
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11
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Ma CIJ, Burgess J, Brill JA. Maturing secretory granules: Where secretory and endocytic pathways converge. Adv Biol Regul 2021; 80:100807. [PMID: 33866198 DOI: 10.1016/j.jbior.2021.100807] [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: 02/18/2021] [Revised: 03/10/2021] [Accepted: 03/18/2021] [Indexed: 10/21/2022]
Abstract
Secretory granules (SGs) are specialized organelles responsible for the storage and regulated release of various biologically active molecules from the endocrine and exocrine systems. Thus, proper SG biogenesis is critical to normal animal physiology. Biogenesis of SGs starts at the trans-Golgi network (TGN), where immature SGs (iSGs) bud off and undergo maturation before fusing with the plasma membrane (PM). How iSGs mature is unclear, but emerging studies have suggested an important role for the endocytic pathway. The requirement for endocytic machinery in SG maturation blurs the line between SGs and another class of secretory organelles called lysosome-related organelles (LROs). Therefore, it is important to re-evaluate the differences and similarities between SGs and LROs.
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Affiliation(s)
- Cheng-I Jonathan Ma
- Cell Biology Program, The Hospital for Sick Children, PGCRL Building, Room 15.9716, 686 Bay Street, Toronto, Ontario, M5G 0A4, Canada; Institute of Medical Science, University of Toronto, Medical Sciences Building, Room 2374, 1 King's College Circle, Toronto, Ontario, M5S 1A8, Canada
| | - Jason Burgess
- Cell Biology Program, The Hospital for Sick Children, PGCRL Building, Room 15.9716, 686 Bay Street, Toronto, Ontario, M5G 0A4, Canada; Department of Molecular Genetics, University of Toronto, Medical Sciences Building, Room 4396, 1 King's College Circle, Toronto, Ontario, M5S 1A8, Canada
| | - Julie A Brill
- Cell Biology Program, The Hospital for Sick Children, PGCRL Building, Room 15.9716, 686 Bay Street, Toronto, Ontario, M5G 0A4, Canada; Institute of Medical Science, University of Toronto, Medical Sciences Building, Room 2374, 1 King's College Circle, Toronto, Ontario, M5S 1A8, Canada; Department of Molecular Genetics, University of Toronto, Medical Sciences Building, Room 4396, 1 King's College Circle, Toronto, Ontario, M5S 1A8, Canada.
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12
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Lv C, Zhang X, Liu Y, Zhang T, Chen H, Zang J, Zheng B, Zhao G. Redesign of protein nanocages: the way from 0D, 1D, 2D to 3D assembly. Chem Soc Rev 2021; 50:3957-3989. [PMID: 33587075 DOI: 10.1039/d0cs01349h] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Compartmentalization is a hallmark of living systems. Through compartmentalization, ubiquitous protein nanocages such as viral capsids, ferritin, small heat shock proteins, and DNA-binding proteins from starved cells fulfill a variety of functions, while their shell-like structures hold great promise for various applications in the field of nanomedicine and nanotechnology. However, the number and structure of natural protein nanocages are limited, and these natural protein nanocages may not be suited for a given application, which might impede their further application as nanovehicles, biotemplates or building blocks. To overcome these shortcomings, different strategies have been developed by scientists to construct artificial protein nanocages, and 1D, 2D and 3D protein arrays with protein nanocages as building blocks through genetic and chemical modification to rival the size and functionality of natural protein nanocages. This review outlines the recent advances in the field of the design and construction of artificial protein nanocages and their assemblies with higher order, summarizes the strategies for creating the assembly of protein nanocages from zero-dimension to three dimensions, and introduces their corresponding applications in the preparation of nanomaterials, electrochemistry, and drug delivery. The review will highlight the roles of both the inter-subunit/intermolecular interactions at the key interface and the protein symmetry in constructing and controlling protein nanocage assemblies with different dimensions.
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Affiliation(s)
- Chenyan Lv
- College of Food Science and Nutritional Engineering, China Agricultural University, Beijing Key Laboratory of Functional Food from Plant Resources, Beijing 100083, China.
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13
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MYBL2 amplification in breast cancer: Molecular mechanisms and therapeutic potential. Biochim Biophys Acta Rev Cancer 2020; 1874:188407. [DOI: 10.1016/j.bbcan.2020.188407] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 07/21/2020] [Accepted: 07/21/2020] [Indexed: 02/08/2023]
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14
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Crawley-Snowdon H, Yang JC, Zaccai NR, Davis LJ, Wartosch L, Herman EK, Bright NA, Swarbrick JS, Collins BM, Jackson LP, Seaman MNJ, Luzio JP, Dacks JB, Neuhaus D, Owen DJ. Mechanism and evolution of the Zn-fingernail required for interaction of VARP with VPS29. Nat Commun 2020; 11:5031. [PMID: 33024112 PMCID: PMC7539009 DOI: 10.1038/s41467-020-18773-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 09/08/2020] [Indexed: 01/13/2023] Open
Abstract
VARP and TBC1D5 are accessory/regulatory proteins of retromer-mediated retrograde trafficking from endosomes. Using an NMR/X-ray approach, we determined the structure of the complex between retromer subunit VPS29 and a 12 residue, four-cysteine/Zn++ microdomain, which we term a Zn-fingernail, two of which are present in VARP. Mutations that abolish VPS29:VARP binding inhibit trafficking from endosomes to the cell surface. We show that VARP and TBC1D5 bind the same site on VPS29 and can compete for binding VPS29 in vivo. The relative disposition of VPS29s in hetero-hexameric, membrane-attached, retromer arches indicates that VARP will prefer binding to assembled retromer coats through simultaneous binding of two VPS29s. The TBC1D5:VPS29 interaction is over one billion years old but the Zn-fingernail appears only in VARP homologues in the lineage directly giving rise to animals at which point the retromer/VARP/TBC1D5 regulatory network became fully established.
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Affiliation(s)
- Harriet Crawley-Snowdon
- MRC Laboratory of Molecular Biology Cambridge Biomedical Campus, Francis Crick Ave, Cambridge, CB2 0QH, UK
| | - Ji-Chun Yang
- MRC Laboratory of Molecular Biology Cambridge Biomedical Campus, Francis Crick Ave, Cambridge, CB2 0QH, UK
| | - Nathan R Zaccai
- CIMR, The Keith Peters Building, Hills Road, Cambridge, CB2 0QQ, UK
| | - Luther J Davis
- CIMR, The Keith Peters Building, Hills Road, Cambridge, CB2 0QQ, UK
| | - Lena Wartosch
- CIMR, The Keith Peters Building, Hills Road, Cambridge, CB2 0QQ, UK
| | - Emily K Herman
- Division of Infectious Disease, Department of Medicine, University of Alberta, Edmonton, Canada, T6G 2G3
| | | | - James S Swarbrick
- Pharmacology and Therapeutics, The University of Melbourne, Parkville, Victoria, 3010, Australia
| | - Brett M Collins
- The University of Queensland, Institute for Molecular Bioscience, St Lucia, QLD, 4072, Australia
| | - Lauren P Jackson
- CIMR, The Keith Peters Building, Hills Road, Cambridge, CB2 0QQ, UK
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, 37232, USA
| | | | - J Paul Luzio
- CIMR, The Keith Peters Building, Hills Road, Cambridge, CB2 0QQ, UK.
| | - Joel B Dacks
- Division of Infectious Disease, Department of Medicine, University of Alberta, Edmonton, Canada, T6G 2G3.
| | - David Neuhaus
- MRC Laboratory of Molecular Biology Cambridge Biomedical Campus, Francis Crick Ave, Cambridge, CB2 0QH, UK.
| | - David J Owen
- CIMR, The Keith Peters Building, Hills Road, Cambridge, CB2 0QQ, UK.
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15
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Kashyap K, Shukla R. Drug Delivery and Targeting to the Brain Through Nasal Route: Mechanisms, Applications and Challenges. Curr Drug Deliv 2020; 16:887-901. [PMID: 31660815 DOI: 10.2174/1567201816666191029122740] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 08/05/2019] [Accepted: 10/15/2019] [Indexed: 02/06/2023]
Abstract
Blood-brain barrier (BBB) provides restrictions for the transportation of various therapeutic agents to the brain. Efforts to directly target the brain by olfactory as well as trigeminal nerve pathway, bypassing BBB, have grown significantly in recent times. The intranasal route of transportation of the drug encompasses ability for the delivery of drug directly to the brain, improves site-specificity in the brain and avoids systemic side effects. In the current era, novel drug delivery systems are useful tools for targeting the brain without providing any harmful effects in nasal mucosa as well as the central nervous system. The complex structure of nasal cavity, mucociliary clearance, degradation by the enzymes present in nasal cavity and pathological conditions like rhinitis, common cold, etc. are the major disputes for nasal drug delivery. The use of nanotechnological approaches like solid lipid nanoparticles, polymeric nanoparticles, nanoemulsions, liposomes and polymeric micelles provides the ability to overcome these barriers. There are several emerging nasal drug delivery technologies produced by various pharmaceutical companies to conquer these hurdles. This review tries to address the recent developments in the area of direct drug delivery to the brain through the nasal route.
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Affiliation(s)
- Kanchan Kashyap
- Department of Pharmaceutics, National Institute of Pharmaceutical Education and Research, Raebareli, India
| | - Rahul Shukla
- Department of Pharmaceutics, National Institute of Pharmaceutical Education and Research, Raebareli, India
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16
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Martinez-Gualda B, Pu SY, Froeyen M, Herdewijn P, Einav S, De Jonghe S. Structure-activity relationship study of the pyridine moiety of isothiazolo[4,3-b]pyridines as antiviral agents targeting cyclin G-associated kinase. Bioorg Med Chem 2019; 28:115188. [PMID: 31757682 DOI: 10.1016/j.bmc.2019.115188] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 10/21/2019] [Accepted: 10/25/2019] [Indexed: 11/26/2022]
Abstract
Previously, we reported the discovery of 3,6-disubstituted isothiazolo[4,3-b]pyridines as potent and selective cyclin G-associated kinase (GAK) inhibitors with promising antiviral activity. In this manuscript, the structure-activity relationship study was expanded to synthesis of isothiazolo[4,3-b]pyridines with modifications of the pyridine moiety. This effort led to the discovery of an isothiazolo[4,3-b]pyridine derivative with a 3,4-dimethoxyphenyl residue at position 5 that displayed low nanomolar GAK binding affinity and antiviral activity against dengue virus.
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Affiliation(s)
- Belén Martinez-Gualda
- KU Leuven, Rega Institute for Medical Research, Laboratory of Medicinal Chemistry, Herestraat 49, 3000 Leuven, Belgium
| | - Szu-Yuan Pu
- Department of Medicine, Division of Infectious Diseases and Geographic Medicine, and Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Mathy Froeyen
- KU Leuven, Rega Institute for Medical Research, Laboratory of Medicinal Chemistry, Herestraat 49, 3000 Leuven, Belgium
| | - Piet Herdewijn
- KU Leuven, Rega Institute for Medical Research, Laboratory of Medicinal Chemistry, Herestraat 49, 3000 Leuven, Belgium
| | - Shirit Einav
- Department of Medicine, Division of Infectious Diseases and Geographic Medicine, and Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Steven De Jonghe
- KU Leuven, Department of Microbiology, Immunology and Transplantation, Rega Institute for Medical Research, Laboratory of Virology and Chemotherapy, Herestraat 49, 3000 Leuven, Belgium.
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17
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Thottacherry JJ, Sathe M, Prabhakara C, Mayor S. Spoiled for Choice: Diverse Endocytic Pathways Function at the Cell Surface. Annu Rev Cell Dev Biol 2019; 35:55-84. [PMID: 31283376 PMCID: PMC6917507 DOI: 10.1146/annurev-cellbio-100617-062710] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Endocytosis has long been identified as a key cellular process involved in bringing in nutrients, in clearing cellular debris in tissue, in the regulation of signaling, and in maintaining cell membrane compositional homeostasis. While clathrin-mediated endocytosis has been most extensively studied, a number of clathrin-independent endocytic pathways are continuing to be delineated. Here we provide a current survey of the different types of endocytic pathways available at the cell surface and discuss a new classification and plausible molecular mechanisms for some of the less characterized pathways. Along with an evolutionary perspective of the origins of some of these pathways, we provide an appreciation of the distinct roles that these pathways play in various aspects of cellular physiology, including the control of signaling and membrane tension.
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Affiliation(s)
- Joseph Jose Thottacherry
- National Centre for Biological Science, Tata Institute for Fundamental Research, Bangalore 560065, India;
| | - Mugdha Sathe
- National Centre for Biological Science, Tata Institute for Fundamental Research, Bangalore 560065, India;
| | - Chaitra Prabhakara
- National Centre for Biological Science, Tata Institute for Fundamental Research, Bangalore 560065, India;
| | - Satyajit Mayor
- National Centre for Biological Science, Tata Institute for Fundamental Research, Bangalore 560065, India;
- Institute for Stem Cell Science and Regenerative Medicine, Bangalore, 560065, India
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18
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Blackburn JB, D'Souza Z, Lupashin VV. Maintaining order: COG complex controls Golgi trafficking, processing, and sorting. FEBS Lett 2019; 593:2466-2487. [PMID: 31381138 PMCID: PMC6771879 DOI: 10.1002/1873-3468.13570] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Revised: 07/31/2019] [Accepted: 08/01/2019] [Indexed: 12/31/2022]
Abstract
The conserved oligomeric Golgi (COG) complex, a multisubunit tethering complex of the CATCHR (complexes associated with tethering containing helical rods) family, controls membrane trafficking and ensures Golgi homeostasis by orchestrating retrograde vesicle targeting within the Golgi. In humans, COG defects lead to severe multisystemic diseases known as COG‐congenital disorders of glycosylation (COG‐CDG). The COG complex both physically and functionally interacts with all classes of molecules maintaining intra‐Golgi trafficking, namely SNAREs, SNARE‐interacting proteins, Rabs, coiled‐coil tethers, and vesicular coats. Here, we review our current knowledge of COG‐related trafficking and glycosylation defects in humans and model organisms, and analyze possible scenarios for the molecular mechanism of the COG orchestrated vesicle targeting.
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Affiliation(s)
- Jessica B Blackburn
- Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Zinia D'Souza
- Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Vladimir V Lupashin
- Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, AR, USA
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19
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Skugor A, Kjos NP, Sundaram AYM, Mydland LT, Ånestad R, Tauson AH, Øverland M. Effects of long-term feeding of rapeseed meal on skeletal muscle transcriptome, production efficiency and meat quality traits in Norwegian Landrace growing-finishing pigs. PLoS One 2019; 14:e0220441. [PMID: 31390356 PMCID: PMC6685631 DOI: 10.1371/journal.pone.0220441] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Accepted: 07/16/2019] [Indexed: 12/30/2022] Open
Abstract
This study was performed to investigate the effects of dietary inclusion of 20% rapeseed meal (RSM) as an alternative to soybean meal (SBM) in a three-month feeding experiment with growing finishing pigs. Dietary alteration affected growth performance, several carcass traits and transcriptional responses in the skeletal muscle, but did not affect measured meat quality traits. In general, pigs fed the RSM test diet exhibited reduced growth performance compared to pigs on SBM control diet. Significant transcriptional changes in the skeletal muscle of growing pigs fed RSM diet were likely the consequence of an increased amount of fiber and higher polyunsaturated fatty acids, and presence of bioactive phytochemicals, such as glucosinolates. RNAseq pipeline using Tophat2-Cuffdiff identified 57 upregulated and 63 downregulated genes in RSM compared to SBM pigs. Significantly enriched among downregulated pathways was p53-mediated signalling involved in cellular proliferation, while activation of negative growth regulators (IER5, KLF10, BTG2, KLF11, RETREG1, PRUNE2) in RSM fed pigs provided further evidence for reduced proliferation and increased cellular death, in accordance with the observed reduction in performance traits. Upregulation of well-known metabolic controllers (PDK4, UCP3, ESRRG and ESRRB), involved in energy homeostasis (glucose and lipid metabolism, and mitochondrial function), suggested less available energy and nutrients in RSM pigs. Furthermore, several genes supported more pronounced proteolysis (ABTB1, OTUD1, PADI2, SPP1) and reduced protein synthesis (THBS1, HSF4, AP1S2) in RSM muscle tissue. In parallel, higher levels of NR4A3, PDK4 and FGF21, and a drop in adropin, ELOVL6 and CIDEC/FSP27 indicated increased lipolysis and fatty acid oxidation, reflective of lower dressing percentage. Finally, pigs exposed to RSM showed greater expression level of genes responsive to oxidative stress, indicated by upregulation of GPX1, GPX2, and TXNIP.
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Affiliation(s)
- Adrijana Skugor
- Department of Animal and Aquacultural Sciences, Faculty of Biosciences, Norwegian University of Life Sciences, Aas, Norway
| | - Nils Petter Kjos
- Department of Animal and Aquacultural Sciences, Faculty of Biosciences, Norwegian University of Life Sciences, Aas, Norway
| | | | - Liv Torunn Mydland
- Department of Animal and Aquacultural Sciences, Faculty of Biosciences, Norwegian University of Life Sciences, Aas, Norway
| | - Ragnhild Ånestad
- Department of Animal and Aquacultural Sciences, Faculty of Biosciences, Norwegian University of Life Sciences, Aas, Norway
| | - Anne-Helene Tauson
- Department of Animal and Aquacultural Sciences, Faculty of Biosciences, Norwegian University of Life Sciences, Aas, Norway
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Margareth Øverland
- Department of Animal and Aquacultural Sciences, Faculty of Biosciences, Norwegian University of Life Sciences, Aas, Norway
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20
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Dighe SN, Ekwudu O, Dua K, Chellappan DK, Katavic PL, Collet TA. Recent update on anti-dengue drug discovery. Eur J Med Chem 2019; 176:431-455. [PMID: 31128447 DOI: 10.1016/j.ejmech.2019.05.010] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 04/12/2019] [Accepted: 05/06/2019] [Indexed: 01/27/2023]
Abstract
Dengue is the most important arthropod-borne viral disease of humans, with more than half of the global population living in at-risk areas. Despite the negative impact on public health, there are no antiviral therapies available, and the only licensed vaccine, Dengvaxia®, has been contraindicated in children below nine years of age. In an effort to combat dengue, several small molecules have entered into human clinical trials. Here, we review anti-DENV molecules and their drug targets that have been published within the past five years (2014-2018). Further, we discuss their probable mechanisms of action and describe a role for classes of clinically approved drugs and also an unclassified class of anti-DENV agents. This review aims to enhance our understanding of novel agents and their cognate targets in furthering innovations in the use of small molecules for dengue drug therapies.
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Affiliation(s)
- Satish N Dighe
- Innovative Medicines Group, Institute of Health & Biomedical Innovation, School of Clinical Sciences, Queensland University of Technology, Brisbane, Australia.
| | - O'mezie Ekwudu
- Innovative Medicines Group, Institute of Health & Biomedical Innovation, School of Clinical Sciences, Queensland University of Technology, Brisbane, Australia
| | - Kamal Dua
- Discipline of Pharmacy, Graduate School of Health, University of Technology Sydney, Ultimo, Australia
| | - Dinesh Kumar Chellappan
- Department of Life Sciences, School of Pharmacy, International Medical University (IMU), Bukit Jalil, Kuala Lumpur, 57000, Malaysia
| | - Peter L Katavic
- Innovative Medicines Group, Institute of Health & Biomedical Innovation, School of Clinical Sciences, Queensland University of Technology, Brisbane, Australia
| | - Trudi A Collet
- Innovative Medicines Group, Institute of Health & Biomedical Innovation, School of Clinical Sciences, Queensland University of Technology, Brisbane, Australia
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21
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Identification of Suppressor of Clathrin Deficiency-1 ( SCD1) and Its Connection to Clathrin-Mediated Endocytosis in Saccharomyces cerevisiae. G3-GENES GENOMES GENETICS 2019; 9:867-877. [PMID: 30679249 PMCID: PMC6404604 DOI: 10.1534/g3.118.200782] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Clathrin is a major coat protein involved in vesicle formation during endocytosis and transport in the endosomal/trans Golgi system. Clathrin is required for normal growth of yeast (Saccharomyces cerevisiae) and in some genetic backgrounds deletion of the clathrin heavy chain gene (CHC1) is lethal. Our lab defined a locus referred to as “suppressor of clathrin deficiency” (SCD1). In the presence of the scd1-v allele (“v” – viable), yeast cells lacking clathrin heavy chain survive but grow slowly, are morphologically abnormal and have many membrane trafficking defects. In the presence of scd1-i (“i”- inviable), chc1∆ causes lethality. As a strategy to identify SCD1, we used pooled linkage analysis and whole genome sequencing. Here, we report that PAL2 (YHR097C) is the SCD1 locus. pal2∆ is synthetic lethal with chc1∆; whereas a deletion of its paralog, PAL1, is not synthetic lethal with clathrin deficiency. Like Pal1, Pal2 has two NPF motifs that are potential binding sites for EH domain proteins such as the early endocytic factor Ede1, and Pal2 associates with Ede1. Also, GFP-tagged Pal2p localizes to cortical patches containing other immobile phase endocytic coat factors. Overall, our data show that PAL2 is the SCD1 locus and the Pal2 protein has characteristics of an early factor involved in clathrin-mediated endocytosis.
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22
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A new role of anterograde motor Kif5b in facilitating large clathrin-coated vesicle mediated endocytosis via regulating clathrin uncoating. Cell Discov 2019; 4:65. [PMID: 30603101 PMCID: PMC6305376 DOI: 10.1038/s41421-018-0067-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Revised: 10/11/2018] [Accepted: 10/11/2018] [Indexed: 11/30/2022] Open
Abstract
Kif5b-driven anterograde transport and clathrin-mediated endocytosis (CME) are responsible for opposite intracellular trafficking, contributing to plasma membrane homeostasis. However, whether and how the two trafficking processes coordinate remain unclear. Here, we show that Kif5b directly interacts with clathrin heavy chain (CHC) at a region close to that for uncoating catalyst (Hsc70) and preferentially localizes on relatively large clathrin-coated vesicles (CCVs). Uncoating in vitro is decreased for CCVs from the cortex of kif5b conditional knockout (mutant) mouse and facilitated by adding Kif5b fragments containing CHC-binding site, while cell peripheral distribution of CHC or Hsc70 keeps unaffected by Kif5b depletion. Furthermore, cellular entry of vesicular stomatitis virus that internalizes into large CCV is inhibited by Kif5b depletion or introducing a dominant-negative Kif5b fragment. These findings showed a new role of Kif5b in regulating large CCV-mediated CME via affecting CCV uncoating, indicating Kif5b as a molecular knot connecting anterograde transport to CME.
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23
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Wouters R, Pu SY, Froeyen M, Lescrinier E, Einav S, Herdewijn P, De Jonghe S. Cyclin G-associated kinase (GAK) affinity and antiviral activity studies of a series of 3-C-substituted isothiazolo[4,3-b]pyridines. Eur J Med Chem 2018; 163:256-265. [PMID: 30529544 DOI: 10.1016/j.ejmech.2018.11.065] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 11/21/2018] [Accepted: 11/27/2018] [Indexed: 12/26/2022]
Abstract
Cyclin G-associated kinase (GAK) is a cellular regulator of the clathrin-associated host adaptor proteins AP-1 and AP-2, which regulates intracellular trafficking of dengue virus during early and late stages of the viral lifecycle. Previously, the discovery of isothiazolo[4,3-b]pyridines as potent and selective GAK inhibitors with promising antiviral activity was reported. In this manuscript, the synthesis of isothiazolo[4,3-b]pyridines with a carbon-linked substituent at position 3 is described by the application of regioselective Suzuki and Sonogashira coupling reactions. A derivative with a 3,4-dimethoxyphenyl residue at position 3 demonstrates low nanomolar binding affinity for GAK and antiviral activity against dengue virus. These findings reveal that appropriate substitution of a phenyl moiety at position 3 of the scaffold can improve GAK binding affinity.
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Affiliation(s)
- Randy Wouters
- Medicinal Chemistry, Rega Institute for Medical Research, KU Leuven, Herestraat 49, bus 1041, 3000, Leuven, Belgium
| | - Szu-Yuan Pu
- Department of Medicine, Division of Infectious Diseases and Geographic Medicine, Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Mathy Froeyen
- Medicinal Chemistry, Rega Institute for Medical Research, KU Leuven, Herestraat 49, bus 1041, 3000, Leuven, Belgium
| | - Eveline Lescrinier
- Medicinal Chemistry, Rega Institute for Medical Research, KU Leuven, Herestraat 49, bus 1041, 3000, Leuven, Belgium
| | - Shirit Einav
- Department of Medicine, Division of Infectious Diseases and Geographic Medicine, Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Piet Herdewijn
- Medicinal Chemistry, Rega Institute for Medical Research, KU Leuven, Herestraat 49, bus 1041, 3000, Leuven, Belgium
| | - Steven De Jonghe
- Medicinal Chemistry, Rega Institute for Medical Research, KU Leuven, Herestraat 49, bus 1041, 3000, Leuven, Belgium.
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24
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Bairwa G, Caza M, Horianopoulos L, Hu G, Kronstad J. Role of clathrin-mediated endocytosis in the use of heme and hemoglobin by the fungal pathogen Cryptococcus neoformans. Cell Microbiol 2018; 21:e12961. [PMID: 30291809 DOI: 10.1111/cmi.12961] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 08/23/2018] [Accepted: 09/17/2018] [Indexed: 12/29/2022]
Abstract
Heme is a major source of iron for pathogens of humans, and its use is critical in determining the outcome of infection and disease. Cryptococcus neoformans is an encapsulated fungal pathogen that causes life-threatening infections in immunocompromised individuals. C. neoformans effectively uses heme as an iron source, but the underlying mechanisms are poorly defined. Non-iron metalloporphyrins (MPPs) are toxic analogues of heme and are thought to enter microbial cells via endogenous heme acquisition systems. We therefore carried out a mutant screen for susceptibility against manganese MPP (MnMPP) to identify new components for heme uptake in C. neoformans. We identified several genes involved in signalling, DNA repair, sugar metabolism, and trafficking that play important roles in susceptibility to MnMPP and in the use of heme as an iron source. We focused on investigating the role of clathrin-mediated endocytosis (CME) and found that several components of CME including Chc1, Las17, Rvs161, and Rvs167 are required for growth on heme and hemoglobin and for endocytosis and intracellular trafficking of these molecules. We show that the hemoglobin uptake process in C. neoformans involves clathrin heavy chain, Chc1, which appears to colocalise with hemoglobin-containing vesicles and to potentially assist in proper delivery of hemoglobin to the vacuole. Additionally, C. neoformans strains lacking Chc1, Las17, Rvs161, or Rvs167 were defective in the elaboration of several key virulence factors, and a las17 mutant was avirulent in a mouse model of cryptococcosis. Overall, this study unveils crucial functions of CME in the use of heme iron by C. neoformans and reveals a role for CME in fungal pathogenesis.
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Affiliation(s)
- Gaurav Bairwa
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada
| | - Mélissa Caza
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada
| | - Linda Horianopoulos
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada.,Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Guanggan Hu
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada
| | - James Kronstad
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada.,Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
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25
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Pu SY, Wouters R, Schor S, Rozenski J, Barouch-Bentov R, Prugar LI, O'Brien CM, Brannan JM, Dye JM, Herdewijn P, De Jonghe S, Einav S. Optimization of Isothiazolo[4,3- b]pyridine-Based Inhibitors of Cyclin G Associated Kinase (GAK) with Broad-Spectrum Antiviral Activity. J Med Chem 2018; 61:6178-6192. [PMID: 29953812 DOI: 10.1021/acs.jmedchem.8b00613] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
There is an urgent need for strategies to combat dengue and other emerging viral infections. We reported that cyclin G-associated kinase (GAK), a cellular regulator of the clathrin-associated host adaptor proteins AP-1 and AP-2, regulates intracellular trafficking of multiple unrelated RNA viruses during early and late stages of the viral lifecycle. We also reported the discovery of potent, selective GAK inhibitors based on an isothiazolo[4,3- b]pyridine scaffold, albeit with moderate antiviral activity. Here, we describe our efforts leading to the discovery of novel isothiazolo[4,3- b]pyridines that maintain high GAK affinity and selectivity. These compounds demonstrate improved in vitro activity against dengue virus, including in human primary dendritic cells, and efficacy against the unrelated Ebola and chikungunya viruses. Moreover, inhibition of GAK activity was validated as an important mechanism of antiviral action of these compounds. These findings demonstrate the potential utility of a GAK-targeted broad-spectrum approach for combating currently untreatable emerging viral infections.
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Affiliation(s)
- Szu-Yuan Pu
- Department of Medicine, Division of Infectious Diseases and Geographic Medicine, and Department of Microbiology and Immunology , Stanford University School of Medicine , Stanford , California 94305 , United States
| | - Randy Wouters
- Medicinal Chemistry, Rega Institute for Medical Research , KU Leuven , Herestraat 49, Bus 1041 , 3000 Leuven , Belgium
| | - Stanford Schor
- Department of Medicine, Division of Infectious Diseases and Geographic Medicine, and Department of Microbiology and Immunology , Stanford University School of Medicine , Stanford , California 94305 , United States
| | - Jef Rozenski
- Medicinal Chemistry, Rega Institute for Medical Research , KU Leuven , Herestraat 49, Bus 1041 , 3000 Leuven , Belgium
| | - Rina Barouch-Bentov
- Department of Medicine, Division of Infectious Diseases and Geographic Medicine, and Department of Microbiology and Immunology , Stanford University School of Medicine , Stanford , California 94305 , United States
| | - Laura I Prugar
- U.S. Army Medical Research Institute of Infectious Diseases , Viral Immunology Branch , Fort Detrick , Maryland 21702 , United States
| | - Cecilia M O'Brien
- U.S. Army Medical Research Institute of Infectious Diseases , Viral Immunology Branch , Fort Detrick , Maryland 21702 , United States
| | - Jennifer M Brannan
- U.S. Army Medical Research Institute of Infectious Diseases , Viral Immunology Branch , Fort Detrick , Maryland 21702 , United States
| | - John M Dye
- U.S. Army Medical Research Institute of Infectious Diseases , Viral Immunology Branch , Fort Detrick , Maryland 21702 , United States
| | - Piet Herdewijn
- Medicinal Chemistry, Rega Institute for Medical Research , KU Leuven , Herestraat 49, Bus 1041 , 3000 Leuven , Belgium
| | - Steven De Jonghe
- Medicinal Chemistry, Rega Institute for Medical Research , KU Leuven , Herestraat 49, Bus 1041 , 3000 Leuven , Belgium
| | - Shirit Einav
- Department of Medicine, Division of Infectious Diseases and Geographic Medicine, and Department of Microbiology and Immunology , Stanford University School of Medicine , Stanford , California 94305 , United States
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26
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Michaels TCT, Bellaiche MMJ, Hagan MF, Knowles TPJ. Kinetic constraints on self-assembly into closed supramolecular structures. Sci Rep 2017; 7:12295. [PMID: 28947758 PMCID: PMC5613031 DOI: 10.1038/s41598-017-12528-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Accepted: 08/04/2017] [Indexed: 11/09/2022] Open
Abstract
Many biological and synthetic systems exploit self-assembly to generate highly intricate closed supramolecular architectures, ranging from self-assembling cages to viral capsids. The fundamental design principles that control the structural determinants of the resulting assemblies are increasingly well-understood, but much less is known about the kinetics of such assembly phenomena and it remains a key challenge to elucidate how these systems can be engineered to assemble in an efficient manner and avoid kinetic trapping. We show here that simple scaling laws emerge from a set of kinetic equations describing the self-assembly of identical building blocks into closed supramolecular structures and that this scaling behavior provides general rules that determine efficient assembly in these systems. Using this framework, we uncover the existence of a narrow range of parameter space that supports efficient self-assembly and reveal that nature capitalizes on this behavior to direct the reliable assembly of viral capsids on biologically relevant timescales.
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Affiliation(s)
- Thomas C T Michaels
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK.,Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, 02138, USA
| | - Mathias M J Bellaiche
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK.,Laboratory of Chemical Physics, National Institute of Digestive and Diabetes and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Michael F Hagan
- Department of Physics, Brandeis University, Waltham, MA, 02454, USA
| | - Tuomas P J Knowles
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK. .,Cavendish Laboratory, Department of Physics, University of Cambridge, J J Thomson Avenue, Cambridge, CB3 1HE, United Kingdom.
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Khan AR, Liu M, Khan MW, Zhai G. Progress in brain targeting drug delivery system by nasal route. J Control Release 2017; 268:364-389. [PMID: 28887135 DOI: 10.1016/j.jconrel.2017.09.001] [Citation(s) in RCA: 198] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Revised: 08/31/2017] [Accepted: 09/01/2017] [Indexed: 12/13/2022]
Abstract
The blood-brain barrier (BBB) restricts the transport of potential therapeutic moieties to the brain. Direct targeting the brain via olfactory and trigeminal neural pathways by passing the BBB has gained an important consideration for delivery of wide range of therapeutics to brain. Intranasal route of transportation directly delivers the drugs to brain without systemic absorption, thus avoiding the side effects and enhancing the efficacy of neurotherapeutics. Over the last several decades, different drug delivery systems (DDSs) have been studied for targeting the brain by the nasal route. Novel DDSs such as nanoparticles (NPs), liposomes and polymeric micelles have gained potential as useful tools for targeting the brain without toxicity in nasal mucosa and central nervous system (CNS). Complex geometry of the nasal cavity presented a big challenge to effective delivery of drugs beyond the nasal valve. Recently, pharmaceutical firms utilized latest and emerging nasal drug delivery technologies to overcome these barriers. This review aims to describe the latest development of brain targeted DDSs via nasal administration. CHEMICAL COMPOUNDS STUDIED IN THIS ARTICLE Carbopol 934p (PubChem CID: 6581) Carboxy methylcellulose (PubChem CID: 24748) Penetratin (PubChem CID: 101111470) Poly lactic-co-glycolic acid (PubChem CID: 23111554) Tween 80 (PubChem CID: 5284448).
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Affiliation(s)
- Abdur Rauf Khan
- Department of Pharmaceutics, College of Pharmacy, Shandong University, 44 Wenhua Xilu, Jinan 250012, China
| | - Mengrui Liu
- Department of Pharmaceutics, College of Pharmacy, Shandong University, 44 Wenhua Xilu, Jinan 250012, China
| | - Muhammad Wasim Khan
- Department of Pharmaceutics, College of Pharmacy, Shandong University, 44 Wenhua Xilu, Jinan 250012, China
| | - Guangxi Zhai
- Department of Pharmaceutics, College of Pharmacy, Shandong University, 44 Wenhua Xilu, Jinan 250012, China.
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Beyond icosahedral symmetry in packings of proteins in spherical shells. Proc Natl Acad Sci U S A 2017; 114:9014-9019. [PMID: 28790186 DOI: 10.1073/pnas.1706825114] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The formation of quasi-spherical cages from protein building blocks is a remarkable self-assembly process in many natural systems, where a small number of elementary building blocks are assembled to build a highly symmetric icosahedral cage. In turn, this has inspired synthetic biologists to design de novo protein cages. We use simple models, on multiple scales, to investigate the self-assembly of a spherical cage, focusing on the regularity of the packing of protein-like objects on the surface. Using building blocks, which are able to pack with icosahedral symmetry, we examine how stable these highly symmetric structures are to perturbations that may arise from the interplay between flexibility of the interacting blocks and entropic effects. We find that, in the presence of those perturbations, icosahedral packing is not the most stable arrangement for a wide range of parameters; rather disordered structures are found to be the most stable. Our results suggest that (i) many designed, or even natural, protein cages may not be regular in the presence of those perturbations and (ii) optimizing those flexibilities can be a possible design strategy to obtain regular synthetic cages with full control over their surface properties.
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Giani M, den Otter WK, Briels WJ. Clathrin Assembly Regulated by Adaptor Proteins in Coarse-Grained Models. Biophys J 2017; 111:222-35. [PMID: 27410749 DOI: 10.1016/j.bpj.2016.06.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 04/29/2016] [Accepted: 06/01/2016] [Indexed: 11/18/2022] Open
Abstract
The assembly of clathrin triskelia into polyhedral cages during endocytosis is regulated by adaptor proteins (APs). We explore how APs achieve this by developing coarse-grained models for clathrin and AP2, employing a Monte Carlo click interaction, to simulate their collective aggregation behavior. The phase diagrams indicate that a crucial role is played by the mechanical properties of the disordered linker segment of AP. We also present a statistical-mechanical theory for the assembly behavior of clathrin, yielding good agreement with our simulations and experimental data from the literature. Adaptor proteins are found to regulate the formation of clathrin coats under certain conditions, but can also suppress the formation of cages.
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Affiliation(s)
- Matteo Giani
- Multi Scale Mechanics, Faculty of Engineering Technology, University of Twente, Enschede, The Netherlands; Computational BioPhysics, Faculty of Science and Technology, University of Twente, Enschede, The Netherlands; MESA+ Institute for Nanotechnology, University of Twente, Enschede, The Netherlands
| | - Wouter K den Otter
- Multi Scale Mechanics, Faculty of Engineering Technology, University of Twente, Enschede, The Netherlands; Computational BioPhysics, Faculty of Science and Technology, University of Twente, Enschede, The Netherlands; MESA+ Institute for Nanotechnology, University of Twente, Enschede, The Netherlands.
| | - Wim J Briels
- Computational BioPhysics, Faculty of Science and Technology, University of Twente, Enschede, The Netherlands; MESA+ Institute for Nanotechnology, University of Twente, Enschede, The Netherlands; Forschungszentrum Jülich, Jülich, Germany
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Venugopal K, Werkmeister E, Barois N, Saliou JM, Poncet A, Huot L, Sindikubwabo F, Hakimi MA, Langsley G, Lafont F, Marion S. Dual role of the Toxoplasma gondii clathrin adaptor AP1 in the sorting of rhoptry and microneme proteins and in parasite division. PLoS Pathog 2017; 13:e1006331. [PMID: 28430827 PMCID: PMC5415223 DOI: 10.1371/journal.ppat.1006331] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 05/03/2017] [Accepted: 04/03/2017] [Indexed: 12/13/2022] Open
Abstract
Toxoplasma gondii possesses a highly polarized secretory system, which efficiently assembles de novo micronemes and rhoptries during parasite replication. These apical secretory organelles release their contents into host cells promoting parasite invasion and survival. Using a CreLox-based inducible knock-out strategy and the ddFKBP over-expression system, we unraveled novel functions of the clathrin adaptor complex TgAP1. First, our data indicate that AP1 in T. gondii likely functions as a conserved heterotetrameric complex composed of the four subunits γ, β, μ1, σ1 and interacts with known regulators of clathrin-mediated vesicular budding such as the unique ENTH-domain containing protein, which we named Epsin-like protein (TgEpsL). Disruption of the μ1 subunit resulted in the mis-sorting of microneme proteins at the level of the Trans-Golgi-Network (TGN). Furthermore, we demonstrated that TgAP1 regulates rhoptry biogenesis by activating rhoptry protein exit from the TGN, but also participates in the post-Golgi maturation process of preROP compartments into apically anchored club-shaped mature organelles. For this latter activity, our data indicate a specific functional relationship between TgAP1 and the Rab5A-positive endosome-like compartment. In addition, we unraveled an original role for TgAP1 in the regulation of parasite division. APμ1-depleted parasites undergo normal daughter cell budding and basal complex assembly but fail to segregate at the end of cytokinesis. The phylum Apicomplexa comprises a large group of obligate intracellular parasites of wide human and agricultural significance. Most notable are Plasmodium, the causative agent of malaria, and Toxoplasma gondii, one of the most common human parasites, responsible for disease of the developing fetus and immune-compromised individuals. Apicomplexa are characterized by the presence of an apical complex consisting of secretory organelles named micronemes (MIC) and rhoptries (ROP). MIC and ROP proteins, released upon host cell recognition, are essential for host cell invasion and parasite survival. After invasion, these organelles are neo-synthesized at each parasite replication cycle. In our study, we demonstrate a crucial role for the T. gondii clathrin adaptor complex AP1 in the vesicular transport of neo-synthesized MIC and ROP proteins, thereby regulating mature apical organelle formation. In addition, we unravel an original role for TgAP1 in the late stages of the parasite division process during daughter cell segregation. Therefore, our study provides new insights into key regulatory mechanisms of the vesicular trafficking system essential for host invasion and intracellular survival of Toxoplasma gondii.
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Affiliation(s)
- Kannan Venugopal
- Centre d'Infection et d'Immunité de Lille, Université de Lille, Inserm U1019, CNRS UMR 8204, CHU Lille, Institut Pasteur de Lille, Lille, France
| | - Elisabeth Werkmeister
- Centre d'Infection et d'Immunité de Lille, Université de Lille, Inserm U1019, CNRS UMR 8204, CHU Lille, Institut Pasteur de Lille, Lille, France
| | - Nicolas Barois
- Centre d'Infection et d'Immunité de Lille, Université de Lille, Inserm U1019, CNRS UMR 8204, CHU Lille, Institut Pasteur de Lille, Lille, France
| | - Jean-Michel Saliou
- Centre d'Infection et d'Immunité de Lille, Université de Lille, Inserm U1019, CNRS UMR 8204, CHU Lille, Institut Pasteur de Lille, Lille, France
| | - Anais Poncet
- Centre d'Infection et d'Immunité de Lille, Université de Lille, Inserm U1019, CNRS UMR 8204, CHU Lille, Institut Pasteur de Lille, Lille, France
| | - Ludovic Huot
- Centre d'Infection et d'Immunité de Lille, Université de Lille, Inserm U1019, CNRS UMR 8204, CHU Lille, Institut Pasteur de Lille, Lille, France
| | - Fabien Sindikubwabo
- IAB, Team Host-pathogen interactions & immunity to infection, Université Grenoble Alpes, Inserm U1209, CNRS UMR5309, Grenoble, France
| | - Mohamed Ali Hakimi
- IAB, Team Host-pathogen interactions & immunity to infection, Université Grenoble Alpes, Inserm U1209, CNRS UMR5309, Grenoble, France
| | - Gordon Langsley
- Laboratoire de Biologie Cellulaire Comparative des Apicomplexes, Faculté de Médicine, Université Paris Descartes-Sorbonne Paris Cité, France. Inserm U1016, CNRS UMR8104, Institut Cochin, Paris, France
| | - Frank Lafont
- Centre d'Infection et d'Immunité de Lille, Université de Lille, Inserm U1019, CNRS UMR 8204, CHU Lille, Institut Pasteur de Lille, Lille, France
| | - Sabrina Marion
- Centre d'Infection et d'Immunité de Lille, Université de Lille, Inserm U1019, CNRS UMR 8204, CHU Lille, Institut Pasteur de Lille, Lille, France
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Goud Gadila SK, Williams M, Saimani U, Delgado Cruz M, Makaraci P, Woodman S, Short JC, McDermott H, Kim K. Yeast dynamin Vps1 associates with clathrin to facilitate vesicular trafficking and controls Golgi homeostasis. Eur J Cell Biol 2017; 96:182-197. [DOI: 10.1016/j.ejcb.2017.02.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Revised: 01/11/2017] [Accepted: 02/16/2017] [Indexed: 10/20/2022] Open
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de León N, Valdivieso MH. The long life of an endocytic patch that misses AP-2. Curr Genet 2016; 62:765-770. [PMID: 27126383 DOI: 10.1007/s00294-016-0605-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 04/15/2016] [Indexed: 10/21/2022]
Abstract
Endocytosis is the process by which cells regulate extracellular fluid uptake and internalize molecules bound to their plasma membrane. This process requires the generation of protein-coated vesicles. In clathrin-mediated endocytosis (CME) the assembly polypeptide 2 (AP-2) adaptor facilitates rapid endocytosis of some plasma membrane receptors by mediating clathrin recruitment to the endocytic site and by connecting cargoes to the clathrin coat. While this adaptor is essential for early embryonic development in mammals, initial results suggested that it is dispensable for endocytosis in unicellular eukaryotes. The drastic effect of depleting AP-2 in metazoa and the mild effect of deleting AP-2 subunits in Saccharomyces cerevisiae have prevented a detailed analysis of the dynamics of endocytic patches in the absence of this adaptor. Using live-cell imaging of Schizosaccharomyces pombe endocytic sites we have shown that eliminating AP-2 perturbs the dynamics of endocytic patches beyond the moment of coat assembly. These perturbations affect the cell growth pattern and cell wall synthesis. Our results highlight the importance of using different model organisms to address the study of conserved aspects of CME.
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Affiliation(s)
- Nagore de León
- Departamento de Microbiología y Genética/Instituto de Biología Funcional y Genómica (IBFG), University of Salamanca/CSIC, Calle Zacarías González 2, 37007, Salamanca, Spain.,Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, UK
| | - M-Henar Valdivieso
- Departamento de Microbiología y Genética/Instituto de Biología Funcional y Genómica (IBFG), University of Salamanca/CSIC, Calle Zacarías González 2, 37007, Salamanca, Spain.
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33
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Kim J, Song SH, Jin Y, Park HJ, Yoon H, Jeon S, Cho SW. Multiphoton luminescent graphene quantum dots for in vivo tracking of human adipose-derived stem cells. NANOSCALE 2016; 8:8512-9. [PMID: 27067507 DOI: 10.1039/c6nr02143c] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The applicability of graphene quantum dots (GQDs) for the in vitro and in vivo live imaging and tracking of different types of human stem cells is investigated. GQDs synthesized by the modified graphite intercalated compound method show efficient cellular uptake with improved biocompatibility and highly sensitive optical properties, indicating their feasibility as a bio-imaging probe for stem cell therapy.
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Affiliation(s)
- Jin Kim
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749, Republic of Korea.
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da Cunha FM, Wanderley-Teixeira V, Teixiera ÁAC, Alves LC. Ultrastructure and histochemistry of the fat body ofAnthonomus grandis(Coleoptera: Curculionidae). INVERTEBR REPROD DEV 2016. [DOI: 10.1080/07924259.2016.1162855] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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35
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Frazier MN, Davies AK, Voehler M, Kendall AK, Borner GHH, Chazin WJ, Robinson MS, Jackson LP. Molecular Basis for the Interaction Between AP4 β4 and its Accessory Protein, Tepsin. Traffic 2016; 17:400-15. [PMID: 26756312 PMCID: PMC4805503 DOI: 10.1111/tra.12375] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Revised: 01/07/2016] [Accepted: 01/07/2016] [Indexed: 01/08/2023]
Abstract
The adaptor protein 4 (AP4) complex (ϵ/β4/μ4/σ4 subunits) forms a non-clathrin coat on vesicles departing the trans-Golgi network. AP4 biology remains poorly understood, in stark contrast to the wealth of molecular data available for the related clathrin adaptors AP1 and AP2. AP4 is important for human health because mutations in any AP4 subunit cause severe neurological problems, including intellectual disability and progressive spastic para- or tetraplegias. We have used a range of structural, biochemical and biophysical approaches to determine the molecular basis for how the AP4 β4 C-terminal appendage domain interacts with tepsin, the only known AP4 accessory protein. We show that tepsin harbors a hydrophobic sequence, LFxG[M/L]x[L/V], in its unstructured C-terminus, which binds directly and specifically to the C-terminal β4 appendage domain. Using nuclear magnetic resonance chemical shift mapping, we define the binding site on the β4 appendage by identifying residues on the surface whose signals are perturbed upon titration with tepsin. Point mutations in either the tepsin LFxG[M/L]x[L/V] sequence or in its cognate binding site on β4 abolish in vitro binding. In cells, the same point mutations greatly reduce the amount of tepsin that interacts with AP4. However, they do not abolish the binding between tepsin and AP4 completely, suggesting the existence of additional interaction sites between AP4 and tepsin. These data provide one of the first detailed mechanistic glimpses at AP4 coat assembly and should provide an entry point for probing the role of AP4-coated vesicles in cell biology, and especially in neuronal function.
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Affiliation(s)
- Meredith N Frazier
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
- Center for Structural Biology, Vanderbilt University, Nashville, TN, USA
| | - Alexandra K Davies
- Department of Clinical Biochemistry, Cambridge Institute for Medical Research, University of Cambridge, Hills Road, Cambridge, UK
| | - Markus Voehler
- Center for Structural Biology, Vanderbilt University, Nashville, TN, USA
- Department of Biochemistry and Chemistry, Vanderbilt University, Nashville, TN, USA
| | - Amy K Kendall
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
- Center for Structural Biology, Vanderbilt University, Nashville, TN, USA
| | - Georg H H Borner
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Walter J Chazin
- Center for Structural Biology, Vanderbilt University, Nashville, TN, USA
- Department of Biochemistry and Chemistry, Vanderbilt University, Nashville, TN, USA
| | - Margaret S Robinson
- Department of Clinical Biochemistry, Cambridge Institute for Medical Research, University of Cambridge, Hills Road, Cambridge, UK
| | - Lauren P Jackson
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
- Center for Structural Biology, Vanderbilt University, Nashville, TN, USA
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Whitfield ST, Burston HE, Bean BDM, Raghuram N, Maldonado-Báez L, Davey M, Wendland B, Conibear E. The alternate AP-1 adaptor subunit Apm2 interacts with the Mil1 regulatory protein and confers differential cargo sorting. Mol Biol Cell 2015; 27:588-98. [PMID: 26658609 PMCID: PMC4751606 DOI: 10.1091/mbc.e15-09-0621] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Accepted: 12/01/2015] [Indexed: 12/31/2022] Open
Abstract
Adaptor complexes are important for cargo sorting in clathrin-coated vesicles. The µ adaptor subunits Apm1 and Apm2 create functionally distinct versions of the yeast AP-1 complex. A novel regulatory protein is identified that selectively binds Apm2-containing complexes and contributes to their membrane recruitment. Heterotetrameric adaptor protein complexes are important mediators of cargo protein sorting in clathrin-coated vesicles. The cell type–specific expression of alternate μ chains creates distinct forms of AP-1 with altered cargo sorting, but how these subunits confer differential function is unclear. Whereas some studies suggest the μ subunits specify localization to different cellular compartments, others find that the two forms of AP-1 are present in the same vesicle but recognize different cargo. Yeast have two forms of AP-1, which differ only in the μ chain. Here we show that the variant μ chain Apm2 confers distinct cargo-sorting functions. Loss of Apm2, but not of Apm1, increases cell surface levels of the v-SNARE Snc1. However, Apm2 is unable to replace Apm1 in sorting Chs3, which requires a dileucine motif recognized by the γ/σ subunits common to both complexes. Apm2 and Apm1 colocalize at Golgi/early endosomes, suggesting that they do not associate with distinct compartments. We identified a novel, conserved regulatory protein that is required for Apm2-dependent sorting events. Mil1 is a predicted lipase that binds Apm2 but not Apm1 and contributes to its membrane recruitment. Interactions with specific regulatory factors may provide a general mechanism to diversify the functional repertoire of clathrin adaptor complexes.
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Affiliation(s)
- Shawn T Whitfield
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Vancouver, University of British Columbia, Vancouver, BC V5Z 4H4, Canada Department of Biochemistry and Molecular Biology and Department of Medical Genetics, Faculty of Medicine, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Helen E Burston
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Vancouver, University of British Columbia, Vancouver, BC V5Z 4H4, Canada Department of Biochemistry and Molecular Biology and Department of Medical Genetics, Faculty of Medicine, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Björn D M Bean
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Vancouver, University of British Columbia, Vancouver, BC V5Z 4H4, Canada Department of Biochemistry and Molecular Biology and Department of Medical Genetics, Faculty of Medicine, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Nandini Raghuram
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Vancouver, University of British Columbia, Vancouver, BC V5Z 4H4, Canada
| | | | - Michael Davey
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Vancouver, University of British Columbia, Vancouver, BC V5Z 4H4, Canada
| | - Beverly Wendland
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218-2685
| | - Elizabeth Conibear
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Vancouver, University of British Columbia, Vancouver, BC V5Z 4H4, Canada Department of Biochemistry and Molecular Biology and Department of Medical Genetics, Faculty of Medicine, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
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Xu J, Li M, Jiao P, Tao H, Wei N, Ma F, Zhang J. Dynamic transcription profiles of "Qinguan" apple (Malus × domestica) leaves in response to Marssonina coronaria inoculation. FRONTIERS IN PLANT SCIENCE 2015; 6:842. [PMID: 26528306 PMCID: PMC4602106 DOI: 10.3389/fpls.2015.00842] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Accepted: 09/25/2015] [Indexed: 05/22/2023]
Abstract
Marssonina apple blotch, caused by the fungus Marssonina coronaria, is one of the most destructive apple diseases in China and East Asia. A better understanding of the plant's response to fungi during pathogenesis is urgently needed to improve plant resistance and to breed resistant cultivars. To address this, the transcriptomes of "Qinguan" (a cultivar with high resistance to M. coronaria) apple leaves were sequenced at 12, 24, 48, and 72 h post-inoculation (hpi) with Marssonina coronaria. The comparative results showed that a total of 1956 genes were differentially expressed between the inoculated and control samples at the 4 time points. Gene ontology (GO) term enrichment analysis of differentially expressed genes (DEGs) revealed changes in cellular component, secondary metabolism including chalcone isomerase activity, phytoalexin biosynthetic process, anthocyanin-containing compound biosynthetic process, lignin biosynthetic process, positive regulation of flavonoid biosynthetic process; and molecular functions or biological processes related to the defense response, biotic stimulus response, wounding response and fungus response. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that DEGs were significantly enriched in flavonoid biosynthesis, vitamin B6 metabolism, phenylpropanoid biosynthesis, and the stilbenoid, diarylheptanoid and gingerol biosynthesis pathways. Furthermore, the importance of changes in cellular components and partial polyphenol compounds when encountering M. coronaria are discussed.
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Affiliation(s)
| | | | | | | | | | | | - Junke Zhang
- The Department of Pomology, College of Horticulture, Northwest A&F UniversityYangling, China
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Role of plasma-membrane-bound sialidase NEU3 in clathrin-mediated endocytosis. Biochem J 2015; 470:131-44. [PMID: 26251452 DOI: 10.1042/bj20141550] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Accepted: 06/24/2015] [Indexed: 12/13/2022]
Abstract
Gangliosides are sialic acid-containing glycosphingolipids mainly expressed at the outer leaflet of the plasma membrane. Sialidase NEU3 is a key enzyme in the catabolism of gangliosides with its up-regulation having been observed in human cancer cells. In the case of CME (clathrin-mediated endocytosis), although this has been widely studied, the role of NEU3 and gangliosides in this cellular process has not yet been established. In the present study, we found an increased internalization of Tf (transferrin), the archetypical cargo for CME, in cells expressing complex gangliosides with high levels of sialylation. The ectopic expression of NEU3 led to a drastic decrease in Tf endocytosis, suggesting the participation of gangliosides in this process. However, the reduction in Tf endocytosis caused by NEU3 was still observed in glycosphingolipid-depleted cells, indicating that NEU3 could operate in a way that is independent of its action on gangliosides. Additionally, internalization of α2-macroglobulin and low-density lipoprotein, other typical ligands in CME, was also decreased in NEU3-expressing cells. In contrast, internalization of cholera toxin β-subunit, which is endocytosed by both clathrin-dependent and clathrin-independent mechanisms, remained unaltered. Kinetic assays revealed that NEU3 caused a reduction in the sorting of endocytosed Tf to early and recycling endosomes, with the Tf binding at the cell surface being also reduced. NEU3-expressing cells showed an altered subcellular distribution of clathrin adaptor AP-2 (adaptor protein 2), but did not reveal any changes in the membrane distribution of clathrin, PtdIns(4,5)P2 or caveolin-1. Overall, these results suggest a specific and novel role of NEU3 in CME.
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Posor Y, Eichhorn-Grünig M, Haucke V. Phosphoinositides in endocytosis. Biochim Biophys Acta Mol Cell Biol Lipids 2015; 1851:794-804. [DOI: 10.1016/j.bbalip.2014.09.014] [Citation(s) in RCA: 124] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2014] [Revised: 08/21/2014] [Accepted: 09/17/2014] [Indexed: 02/04/2023]
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Paczkowski JE, Richardson BC, Fromme JC. Cargo adaptors: structures illuminate mechanisms regulating vesicle biogenesis. Trends Cell Biol 2015; 25:408-16. [PMID: 25795254 DOI: 10.1016/j.tcb.2015.02.005] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Revised: 02/11/2015] [Accepted: 02/19/2015] [Indexed: 12/29/2022]
Abstract
Cargo adaptors sort transmembrane protein cargos into nascent vesicles by binding directly to their cytosolic domains. Recent studies have revealed previously unappreciated roles for cargo adaptors and regulatory mechanisms governing their function. The adaptor protein (AP)-1 and AP-2 clathrin adaptors switch between open and closed conformations that ensure they function at the right place at the right time. The exomer cargo adaptor has a direct role in remodeling the membrane for vesicle fission. Several different cargo adaptors functioning in distinct trafficking pathways at the Golgi are similarly regulated through bivalent binding to the ADP-ribosylation factor 1 (Arf1) GTPase, potentially enabling regulation by a threshold concentration of Arf1. Taken together, these studies highlight that cargo adaptors do more than just adapt cargos.
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Affiliation(s)
- Jon E Paczkowski
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA
| | - Brian C Richardson
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA
| | - J Christopher Fromme
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA.
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41
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Mechanisms Underlying Anomalous Diffusion in the Plasma Membrane. CURRENT TOPICS IN MEMBRANES 2015; 75:167-207. [DOI: 10.1016/bs.ctm.2015.03.002] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Septin6 and Septin7 GTP binding proteins regulate AP-3- and ESCRT-dependent multivesicular body biogenesis. PLoS One 2014; 9:e109372. [PMID: 25380047 PMCID: PMC4224394 DOI: 10.1371/journal.pone.0109372] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Accepted: 09/04/2014] [Indexed: 11/19/2022] Open
Abstract
Septins (SEPTs) form a family of GTP-binding proteins implicated in cytoskeleton and membrane organization, cell division and host/pathogen interactions. The precise function of many family members remains elusive. We show that SEPT6 and SEPT7 complexes bound to F-actin regulate protein sorting during multivesicular body (MVB) biogenesis. These complexes bind AP-3, an adapter complex sorting cargos destined to remain in outer membranes of maturing endosomes, modulate AP-3 membrane interactions and the motility of AP-3-positive endosomes. These SEPT-AP interactions also influence the membrane interaction of ESCRT (endosomal-sorting complex required for transport)-I, which selects ubiquitinated cargos for degradation inside MVBs. Whereas our findings demonstrate that SEPT6 and SEPT7 function in the spatial, temporal organization of AP-3- and ESCRT-coated membrane domains, they uncover an unsuspected coordination of these sorting machineries during MVB biogenesis. This requires the E3 ubiquitin ligase LRSAM1, an AP-3 interactor regulating ESCRT-I sorting activity and whose mutations are linked with Charcot-Marie-Tooth neuropathies.
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43
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Marszalowicz GP, Snook AE, Magee MS, Merlino D, Lisa DBB, Waldman SA. GUCY2C lysosomotropic endocytosis delivers immunotoxin therapy to metastatic colorectal cancer. Oncotarget 2014; 5:9460-71. [PMID: 25294806 PMCID: PMC4253446 DOI: 10.18632/oncotarget.2455] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Accepted: 09/07/2014] [Indexed: 02/06/2023] Open
Abstract
The emergence of targeted cancer therapy has been limited by the paucity of determinants which are tumor-specific and generally associated with disease, and have cell dynamics which effectively deploy cytotoxic payloads. Guanylyl cyclase C (GUCY2C) may be ideal for targeting because it is normally expressed only in insulated barrier compartments, including intestine and brain, but over-expressed by systemic metastatic colorectal tumors. Here, we reveal that GUCY2C rapidly internalizes from the cell surface to lysosomes in intestinal and colorectal cancer cells. Endocytosis is independent of ligand binding and receptor activation, and is mediated by clathrin. This mechanism suggests a design for immunotoxins comprising a GUCY2C-directed monoclonal antibody conjugated through a reducible disulfide linkage to ricin A chain, which is activated to a potent cytotoxin in lysosomes. Indeed, this immunotoxin specifically killed GUCY2C-expressing colorectal cancer cells in a lysosomal- and clathrin-dependent fashion. Moreover, this immunotoxin reduced pulmonary tumors>80% (p<0.001), and improved survival 25% (p<0.001), in mice with established colorectal cancer metastases. Further, therapeutic efficacy was achieved without histologic evidence of toxicity in normal tissues. These observations support GUCY2C-targeted immunotoxins as novel therapeutics for metastatic tumors originating in the GI tract, including colorectum, stomach, esophagus, and pancreas.
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Affiliation(s)
- Glen P. Marszalowicz
- School of Biomedical Engineering, Science, and Health Systems, Drexel University, Philadelphia, PA, USA
| | - Adam E. Snook
- Department of Pharmacology and Experimental Therapeutics, Thomas Jefferson University, Philadelphia, PA, USA
| | - Michael S. Magee
- Department of Pharmacology and Experimental Therapeutics, Thomas Jefferson University, Philadelphia, PA, USA
| | - Dante Merlino
- Department of Pharmacology and Experimental Therapeutics, Thomas Jefferson University, Philadelphia, PA, USA
| | | | - Scott A. Waldman
- Department of Pharmacology and Experimental Therapeutics, Thomas Jefferson University, Philadelphia, PA, USA
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Tourdot RW, Bradley RP, Ramakrishnan N, Radhakrishnan R. Multiscale computational models in physical systems biology of intracellular trafficking. IET Syst Biol 2014; 8:198-213. [PMID: 25257021 PMCID: PMC4336166 DOI: 10.1049/iet-syb.2013.0057] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Revised: 07/03/2014] [Accepted: 08/08/2014] [Indexed: 01/19/2023] Open
Abstract
In intracellular trafficking, a definitive understanding of the interplay between protein binding and membrane morphology remains incomplete. The authors describe a computational approach by integrating coarse-grained molecular dynamics (CGMD) simulations with continuum Monte Carlo (CM) simulations of the membrane to study protein-membrane interactions and the ensuing membrane curvature. They relate the curvature field strength discerned from the molecular level to its effect at the cellular length-scale. They perform thermodynamic integration on the CM model to describe the free energy landscape of vesiculation in clathrin-mediated endocytosis. The method presented here delineates membrane morphologies and maps out the free energy changes associated with membrane remodeling due to varying coat sizes, coat curvature strengths, membrane bending rigidities, and tensions; furthermore several constraints on mechanisms underlying clathrin-mediated endocytosis have also been identified, Their CGMD simulations have revealed the importance of PIP2 for stable binding of proteins essential for curvature induction in the bilayer and have provided a molecular basis for the positive curvature induction by the epsin N-terminal homology (EIMTH) domain. Calculation of the free energy landscape for vesicle budding has identified the critical size and curvature strength of a clathrin coat required for nucleation and stabilisation of a mature vesicle.
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Affiliation(s)
- Richard W Tourdot
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Ryan P Bradley
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Natesan Ramakrishnan
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Ravi Radhakrishnan
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA 19104, USA.
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Bitsikas V, Corrêa IR, Nichols BJ. Clathrin-independent pathways do not contribute significantly to endocytic flux. eLife 2014; 3:e03970. [PMID: 25232658 PMCID: PMC4185422 DOI: 10.7554/elife.03970] [Citation(s) in RCA: 127] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Accepted: 09/15/2014] [Indexed: 12/25/2022] Open
Abstract
Several different endocytic pathways have been proposed to function in mammalian cells. Clathrin-coated pits are well defined, but the identity, mechanism and function of alternative pathways have been controversial. Here we apply universal chemical labelling of plasma membrane proteins to define all primary endocytic vesicles, and labelling of specific proteins with a reducible SNAP-tag substrate. These approaches provide high temporal resolution and stringent discrimination between surface-connected and intracellular membranes. We find that at least 95% of the earliest detectable endocytic vesicles arise from clathrin-coated pits. GPI-anchored proteins, candidate cargoes for alternate pathways, are also found to enter the cell predominantly via coated pits. Experiments employing a mutated clathrin adaptor reveal distinct mechanisms for sorting into coated pits, and thereby explain differential effects on the uptake of transferrin and GPI-anchored proteins. These data call for a revision of models for the activity and diversity of endocytic pathways in mammalian cells. DOI:http://dx.doi.org/10.7554/eLife.03970.001 Cells are enclosed by a ‘plasma membrane’ that allows nutrients and certain small molecules to move in and out of cells. Larger molecules—such as proteins—are carried into cells through a process known as endocytosis, where part of the plasma membrane engulfs the molecule and transports it through the cell inside a bubble-like compartment called a vesicle. There may be several different ways by which endocytosis can occur. The most common method involves a protein known as clathrin, which coats part of the plasma membrane on the side facing the inside of the cell. This causes the membrane to deform into a pit. The pit grows around, and eventually completely surrounds, the molecule to be transported, at which point the clathrin-coated membrane pinches off from the rest of the plasma membrane to form a vesicle. Other forms of endocytosis do not need clathrin to form vesicles, and so are collectively known as clathrin-independent endocytosis. However, the details of how these other types of endocytosis work and how important they are for moving molecules into the cell remain unclear. This is partly because it is difficult to identify particular types of endocytosis. Previous attempts to do this have involved trying to identify molecules that are specifically and solely associated with that type of endocytosis, and using these to track the vesicle. However, few—if any—such molecules are known for clathrin-independent methods of endocytosis. Another approach is to inhibit the formation of clathrin-coated pits and study those molecules that are still taken into cells. The problem here is that incomplete inhibition can make interpreting the results difficult. Furthermore, complete inhibition of an important process like clathrin-dependent endocytosis is likely to have severe effects on many other aspects of cell function. Bitsikas et al. have developed a new method that allows a vesicle to be identified—regardless of how it forms—in cells that have not been treated with inhibitors. This method involves labelling proteins in the plasma membrane with a chemical that allows them to be traced, and so shows when they are included in vesicle membranes. Importantly, this new method can provide very accurate information as to whether or not proteins have been included in vesicles, and this may provide advantages over previous approaches. Bitsikas et al. selected a group of proteins that are thought to only enter cells in a clathrin-independent manner, but unexpectedly found that these proteins predominantly enter cells through clathrin-coated vesicles. Further analysis revealed that approximately 95% of all molecules that enter cells by endocytosis are taken up via clathrin-coated endocytosis. Therefore, clathrin-independent endocytosis does not make a significant contribution to the transport of large molecules into cells. These results are at odds with current thinking in the field. Future work could reveal whether the techniques applied by Bitsikas et al. detect more active clathrin-independent endocytosis in special situations, for example during cell migration, or in specific cell types. DOI:http://dx.doi.org/10.7554/eLife.03970.002
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Affiliation(s)
- Vassilis Bitsikas
- Department of Cell Biology, Medical Research Council Laboratory of Molecular Biology, Cambridge, United Kingdom
| | | | - Benjamin J Nichols
- Department of Cell Biology, Medical Research Council Laboratory of Molecular Biology, Cambridge, United Kingdom
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SDF-1 chemokine signalling modulates the apoptotic responses to iron deprivation of clathrin-depleted DT40 cells. PLoS One 2014; 9:e106278. [PMID: 25162584 PMCID: PMC4146602 DOI: 10.1371/journal.pone.0106278] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Accepted: 08/05/2014] [Indexed: 11/29/2022] Open
Abstract
We have previously deleted both endogenous copies of the clathrin heavy-chain gene in the chicken pre B-cell-line DT40 and replaced them with clathrin under the control of a tetracycline-regulatable promoter (Tet-Off). The originally derived cell-line DKO-S underwent apoptosis when clathrin expression was repressed. We have also described a cell-line DKO-R derived from DKO-S cells that was less sensitive to clathrin-depletion. Here we show that the restriction of transferrin uptake, resulting in iron deprivation, is responsible for the lethal consequence of clathrin-depletion. We further show that the DKO-R cells have up-regulated an anti-apoptotic survival pathway based on the chemokine SDF-1 and its receptor CXCR4. Our work clarifies several puzzling features of clathrin-depleted DT40 cells and reveals an example of how SDF-1/CXCR4 signalling can abrogate pro-apoptotic pathways and increase cell survival. We propose that the phenomenon described here has implications for the therapeutic approach to a variety of cancers.
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Abstract
In vitro reconstitution is prerequisite to investigate complex cellular functions at the molecular level. Reconstitution systems range from combining complete cellular cytosol with organelle-enriched membrane fractions to liposomal systems where all components are chemically defined and can be chosen at will. Here, we describe the in vitro reconstitution of COPI-coated vesicles from semi-intact cells. Efficient vesicle formation is achieved by simple incubation of permeabilized cells with the minimal set of coat proteins Arf1 and coatomer, and guanosine trinucleotides. GTP hydrolysis or any mechanical manipulations are not required for efficient COPI vesicle release.
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Croisé P, Estay-Ahumada C, Gasman S, Ory S. Rho GTPases, phosphoinositides, and actin: a tripartite framework for efficient vesicular trafficking. Small GTPases 2014; 5:e29469. [PMID: 24914539 DOI: 10.4161/sgtp.29469] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Rho GTPases are well known regulators of the actin cytoskeleton that act by binding and activating actin nucleators. They are therefore involved in many actin-based processes, including cell migration, cell polarity, and membrane trafficking. With the identification of phosphoinositide kinases and phosphatases as potential binding partners or effectors, Rho GTPases also appear to participate in the regulation of phosphoinositide metabolism. Since both actin dynamics and phosphoinositide turnover affect the efficiency and the fidelity of vesicle transport between cell compartments, Rho GTPases have emerged as critical players in membrane trafficking. Rho GTPase activity, actin remodeling, and phosphoinositide metabolism need to be coordinated in both space and time to ensure the progression of vesicles along membrane trafficking pathways. Although most molecular pathways are still unclear, in this review, we will highlight recent advances made in our understanding of how Rho-dependent signaling pathways organize actin dynamics and phosphoinositides and how phosphoinositides potentially provide negative feedback to Rho GTPases during endocytosis, exocytosis and membrane exchange between intracellular compartments.
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Affiliation(s)
- Pauline Croisé
- CNRS UPR 3212; Institut des Neurosciences Cellulaires et Intégratives; Université de Strasbourg; Strasbourg, France
| | - Catherine Estay-Ahumada
- CNRS UPR 3212; Institut des Neurosciences Cellulaires et Intégratives; Université de Strasbourg; Strasbourg, France
| | - Stéphane Gasman
- CNRS UPR 3212; Institut des Neurosciences Cellulaires et Intégratives; Université de Strasbourg; Strasbourg, France
| | - Stéphane Ory
- CNRS UPR 3212; Institut des Neurosciences Cellulaires et Intégratives; Université de Strasbourg; Strasbourg, France
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49
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Böcking T, Aguet F, Rapoport I, Banzhaf M, Yu A, Zeeh JC, Kirchhausen T. Key interactions for clathrin coat stability. Structure 2014; 22:819-29. [PMID: 24815030 DOI: 10.1016/j.str.2014.04.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Revised: 03/31/2014] [Accepted: 04/02/2014] [Indexed: 11/29/2022]
Abstract
Clathrin-coated vesicles are major carriers of vesicular traffic in eukaryotic cells. This endocytic pathway relies on cycles of clathrin coat assembly and Hsc70-mediated disassembly. Here we identify histidine residues as major determinants of lattice assembly and stability. They are located at the invariant interface between the proximal and distal segments of clathrin heavy chains, in triskelions centered on two adjacent vertices of the coated-vesicle lattice. Mutation of these histidine residues to glutamine alters the pH dependence of coat stability. We then describe single-particle fluorescence imaging experiments in which we follow the effect of these histidine mutations on susceptibility to Hsc70-dependent uncoating. Coats destabilized by these mutations require fewer Hsc70 molecules to initiate disassembly, as predicted by a model in which Hsc70 traps conformational distortions during the auxilin- and Hsc70:ATP-mediated uncoating reaction.
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Affiliation(s)
- Till Böcking
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA; Centre for Vascular Research, University of New South Wales, Sydney NSW 2052 Australia.
| | - François Aguet
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Iris Rapoport
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA; Program in Cellular and Molecular Medicine at Boston Children's Hospital, Boston, MA 02115, USA
| | - Manuel Banzhaf
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA; Program in Cellular and Molecular Medicine at Boston Children's Hospital, Boston, MA 02115, USA
| | - Anan Yu
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA; Program in Cellular and Molecular Medicine at Boston Children's Hospital, Boston, MA 02115, USA
| | - Jean Christophe Zeeh
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA; Program in Cellular and Molecular Medicine at Boston Children's Hospital, Boston, MA 02115, USA
| | - Tom Kirchhausen
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA; Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA; Program in Cellular and Molecular Medicine at Boston Children's Hospital, Boston, MA 02115, USA.
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50
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Chakraborty S, Umasankar PK, Preston GM, Khandelwal P, Apodaca G, Watkins SC, Traub LM. A phosphotyrosine switch for cargo sequestration at clathrin-coated buds. J Biol Chem 2014; 289:17497-514. [PMID: 24798335 DOI: 10.1074/jbc.m114.556589] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The AP-2 clathrin adaptor complex oversees endocytic cargo selection in two parallel but independent manners. First, by physically engaging peptide-based endocytic sorting signals, a subset of clathrin-dependent transmembrane cargo is directly collected into assembling buds. Synchronously, by interacting with an assortment of clathrin-associated sorting proteins (CLASPs) that independently select different integral membrane cargo for inclusion within the incipient bud, AP-2 handles additional cargo capture indirectly. The distal platform subdomain of the AP-2 β2 subunit appendage is a privileged CLASP-binding surface that recognizes a cognate, short α-helical interaction motif. This signal, found in the CLASPs β-arrestin and the autosomal recessive hypercholesterolemia (ARH) protein, docks into an elongated groove on the β2 appendage platform. Tyr-888 is a critical constituent of this spatially confined β2 appendage contact interface and is phosphorylated in numerous high-throughput proteomic studies. We find that a phosphomimetic Y888E substitution does not interfere with incorporation of expressed β2-YFP subunit into AP-2 or alter AP-2 deposition at surface clathrin-coated structures. The Y888E mutation does not affect interactions involving the sandwich subdomain of the β2 appendage, indicating that the mutated appendage is folded and operational. However, the Y888E, but not Y888F, switch selectively uncouples interactions with ARH and β-arrestin. Phyogenetic conservation of Tyr-888 suggests that this residue can reversibly control occupancy of the β2 platform-binding site and, hence, cargo sorting.
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Affiliation(s)
| | | | | | - Puneet Khandelwal
- the Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261
| | - Gerard Apodaca
- the Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261
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