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Barreca V, Boussadia Z, Polignano D, Galli L, Tirelli V, Sanchez M, Falchi M, Bertuccini L, Iosi F, Tatti M, Sargiacomo M, Fiani ML. Metabolic labelling of a subpopulation of small extracellular vesicles using a fluorescent palmitic acid analogue. J Extracell Vesicles 2023; 12:e12392. [PMID: 38072803 PMCID: PMC10710952 DOI: 10.1002/jev2.12392] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 11/14/2023] [Accepted: 11/17/2023] [Indexed: 12/18/2023] Open
Abstract
Exosomes are among the most puzzling vehicles of intercellular communication, but several crucial aspects of their biogenesis remain elusive, primarily due to the difficulty in purifying vesicles with similar sizes and densities. Here we report an effective methodology for labelling small extracellular vesicles (sEV) using Bodipy FL C16, a fluorescent palmitic acid analogue. In this study, we present compelling evidence that the fluorescent sEV population derived from Bodipy C16-labelled cells represents a discrete subpopulation of small exosomes following an intracellular pathway. Rapid cellular uptake and metabolism of Bodipy C16 resulted in the incorporation of fluorescent phospholipids into intracellular organelles specifically excluding the plasma membrane and ultimately becoming part of the exosomal membrane. Importantly, our fluorescence labelling method facilitated accurate quantification and characterization of exosomes, overcoming the limitations of nonspecific dye incorporation into heterogeneous vesicle populations. The characterization of Bodipy-labelled exosomes reveals their enrichment in tetraspanin markers, particularly CD63 and CD81, and in minor proportion CD9. Moreover, we employed nanoFACS sorting and electron microscopy to confirm the exosomal nature of Bodipy-labelled vesicles. This innovative metabolic labelling approach, based on the fate of a fatty acid, offers new avenues for investigating exosome biogenesis and functional properties in various physiological and pathological contexts.
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Affiliation(s)
- Valeria Barreca
- National Center for Global HealthIstituto Superiore di SanitàRomeItaly
| | | | - Deborah Polignano
- National Center for Global HealthIstituto Superiore di SanitàRomeItaly
| | - Lorenzo Galli
- National Center for Global HealthIstituto Superiore di SanitàRomeItaly
| | | | | | - Mario Falchi
- National AIDS CenterIstituto Superiore di SanitàRomeItaly
| | | | | | - Massimo Tatti
- Department of Oncology and Molecular MedicineIstituto Superiore di SanitàRomeItaly
| | | | - Maria Luisa Fiani
- National Center for Global HealthIstituto Superiore di SanitàRomeItaly
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2
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Thiyagarajah K, Basic M, Hildt E. Cellular Factors Involved in the Hepatitis D Virus Life Cycle. Viruses 2023; 15:1687. [PMID: 37632029 PMCID: PMC10459925 DOI: 10.3390/v15081687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 07/30/2023] [Accepted: 08/01/2023] [Indexed: 08/27/2023] Open
Abstract
Hepatitis D virus (HDV) is a defective RNA virus with a negative-strand RNA genome encompassing less than 1700 nucleotides. The HDV genome encodes only for one protein, the hepatitis delta antigen (HDAg), which exists in two forms acting as nucleoproteins. HDV depends on the envelope proteins of the hepatitis B virus as a helper virus for packaging its ribonucleoprotein complex (RNP). HDV is considered the causative agent for the most severe form of viral hepatitis leading to liver fibrosis/cirrhosis and hepatocellular carcinoma. Many steps of the life cycle of HDV are still enigmatic. This review gives an overview of the complete life cycle of HDV and identifies gaps in knowledge. The focus is on the description of cellular factors being involved in the life cycle of HDV and the deregulation of cellular pathways by HDV with respect to their relevance for viral replication, morphogenesis and HDV-associated pathogenesis. Moreover, recent progress in antiviral strategies targeting cellular structures is summarized in this article.
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Affiliation(s)
| | | | - Eberhard Hildt
- Paul-Ehrlich-Institute, Department of Virology, D-63225 Langen, Germany; (K.T.); (M.B.)
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Grziwa S, Schäfer JH, Nicastro R, Arens A, De Virgilio C, Fröhlich F, Moeller A, Gao J, Langemeyer L, Ungermann C. Yck3 casein kinase-mediated phosphorylation determines Ivy1 localization and function at endosomes and vacuole. J Cell Sci 2023:312552. [PMID: 37259913 DOI: 10.1242/jcs.260889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Accepted: 05/18/2023] [Indexed: 06/02/2023] Open
Abstract
The casein kinase Yck3 is a central regulator at the vacuole that phosphorylates several proteins involved in membrane trafficking. Here, we set out to identify novel substrates. We localized endogenously tagged Yck3 not only at the vacuole, but also on endosomes. To disable Yck3 function, we generated a kinase-deficient mutant and thus identified the I-BAR-protein Ivy1 as a novel Yck3 substrate. Ivy1 localizes to both endosomes and vacuoles, and Yck3 controls this localization. A phosphomimetic Ivy1-SD mutant was found primarily on vacuoles, its non-phosphorylatable SA variant strongly localized to endosomes, similar to what is observed upon deletion of Yck3. In vitro analysis revealed that Yck3-mediated phosphorylation strongly promoted Ivy1 recruitment to liposomes carrying Rab7-like Ypt7. Modelling of Ivy1 with Ypt7 identified binding sites for Ypt7 and a positively charged patch, which are both required for Ivy1 localization. Strikingly, Ivy1 mutations in either site resulted in more cells with multilobed vacuoles, suggesting a partial defect in its membrane biogenesis. Our data thus indicate that Yck3-mediated phosphorylation controls both localization and function of Ivy1 in endolysosomal biogenesis.
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Affiliation(s)
- Sophie Grziwa
- Osnabrück University, Department of Biology/Chemistry, Biochemistry section, Barbarastrasse 13, 49076 Osnabrück, Germany
| | - Jan-Hannes Schäfer
- Osnabrück University, Department of Biology/Chemistry, Structural Biology, Barbarastrasse 13, 49076 Osnabrück, Germany
| | - Raffaele Nicastro
- Department of Biology, University of Fribourg, Chemin du Musée, CH-1700 Fribourg, Switzerland
| | - Annabel Arens
- Osnabrück University, Department of Biology/Chemistry, Biochemistry section, Barbarastrasse 13, 49076 Osnabrück, Germany
| | - Claudio De Virgilio
- Department of Biology, University of Fribourg, Chemin du Musée, CH-1700 Fribourg, Switzerland
| | - Florian Fröhlich
- Osnabrück University, Department of Biology/Chemistry, Molecular Membrane Biology, Barbarastrasse 13, 49076 Osnabrück, Germany
- Osnabrück University, Center of Cellular Nanoanalytic Osnabrück (CellNanOs), Barbarastrasse 11, 49076 Osnabrück, Germany
| | - Arne Moeller
- Osnabrück University, Department of Biology/Chemistry, Structural Biology, Barbarastrasse 13, 49076 Osnabrück, Germany
- Osnabrück University, Center of Cellular Nanoanalytic Osnabrück (CellNanOs), Barbarastrasse 11, 49076 Osnabrück, Germany
| | - Jieqiong Gao
- Osnabrück University, Department of Biology/Chemistry, Biochemistry section, Barbarastrasse 13, 49076 Osnabrück, Germany
| | - Lars Langemeyer
- Osnabrück University, Department of Biology/Chemistry, Biochemistry section, Barbarastrasse 13, 49076 Osnabrück, Germany
- Osnabrück University, Center of Cellular Nanoanalytic Osnabrück (CellNanOs), Barbarastrasse 11, 49076 Osnabrück, Germany
| | - Christian Ungermann
- Osnabrück University, Department of Biology/Chemistry, Biochemistry section, Barbarastrasse 13, 49076 Osnabrück, Germany
- Osnabrück University, Center of Cellular Nanoanalytic Osnabrück (CellNanOs), Barbarastrasse 11, 49076 Osnabrück, Germany
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4
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Jiang TY, Shi YY, Cui XW, Pan YF, Lin YK, Feng XF, Ding ZW, Yang C, Tan YX, Dong LW, Wang HY. PTEN Deficiency Facilitates Exosome Secretion and Metastasis in Cholangiocarcinoma by Impairing TFEB-mediated Lysosome Biogenesis. Gastroenterology 2023; 164:424-438. [PMID: 36436593 DOI: 10.1053/j.gastro.2022.11.025] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 10/24/2022] [Accepted: 11/10/2022] [Indexed: 11/27/2022]
Abstract
BACKGROUND & AIMS In eukaryotes, the ubiquitin-proteasome system and the autophagy-lysosome pathway are essential for maintaining cellular proteostasis and associated with cancer progression. Our previous studies have demonstrated that phosphatase and tensin homolog (PTEN), one of the most frequently mutated genes in human cancers, limits proteasome abundance and determines chemosensitivity to proteasome inhibitors in cholangiocarcinoma (CCA). However, whether PTEN regulates the lysosome pathway remains unclear. METHODS We tested the effects of PTEN on lysosome biogenesis and exosome secretion using loss- and gain-of-function strategies in CCA cell lines. Using in vitro dephosphorylation assays, we explored the regulatory mechanism between PTEN and the key regulator of lysosome biogenesis, transcription factor EB (TFEB). Using the migration assays, invasion assays, and trans-splenic liver metastasis mouse models, we evaluated the function of PTEN deficiency, TFEB-mediated lysosome biogenesis, and exosome secretion on tumor metastasis. Moreover, we investigated the clinical significance of PTEN expression and exosome secretion by retrospective analysis. RESULTS PTEN facilitated lysosome biogenesis and acidification through its protein phosphatase activity to dephosphorylate TFEB at Ser211. Notably, PTEN deficiency increased exosome secretion by reducing lysosome-mediated degradation of multi-vesicular bodies, which further facilitated the proliferation and invasion of CCA. TFEB agonist curcumin analog C1 restrained the metastatic phenotype caused by PTEN deficiency in mouse models, and we highlighted the correlation between PTEN deficiency and exosome secretion in clinical cohorts. CONCLUSIONS In CCA, PTEN deficiency impairs lysosome biogenesis to facilitate exosome secretion and cancer metastasis in a TFEB phosphorylation-dependent manner.
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Affiliation(s)
- Tian-Yi Jiang
- National Center for Liver Cancer, the Third Affiliated Hospital of Naval Medical University, Shanghai, China; International Cooperation Laboratory on Signal Transduction, Eastern Hepatobiliary Surgery Institute, the Naval Medical University, Shanghai, China
| | - Yuan-Yuan Shi
- National Center for Liver Cancer, the Third Affiliated Hospital of Naval Medical University, Shanghai, China; The First Affiliated Hospital of Naval Medical University, Shanghai, China
| | - Xiao-Wen Cui
- National Center for Liver Cancer, the Third Affiliated Hospital of Naval Medical University, Shanghai, China; Department of Oncology, Eastern Hepatobiliary Surgery Hospital, the Naval Military Medical University, Shanghai, China
| | - Yu-Fei Pan
- International Cooperation Laboratory on Signal Transduction, Eastern Hepatobiliary Surgery Institute, the Naval Medical University, Shanghai, China
| | - Yun-Kai Lin
- National Center for Liver Cancer, the Third Affiliated Hospital of Naval Medical University, Shanghai, China; International Cooperation Laboratory on Signal Transduction, Eastern Hepatobiliary Surgery Institute, the Naval Medical University, Shanghai, China
| | - Xiao-Fan Feng
- International Cooperation Laboratory on Signal Transduction, Eastern Hepatobiliary Surgery Institute, the Naval Medical University, Shanghai, China
| | - Zhi-Wen Ding
- Department of Surgery, Eastern Hepatobiliary Surgery Hospital, the Naval Medical University, Shanghai, China
| | - Chun Yang
- Children's Hospital of Soochow University, Suzhou, P. R. China
| | - Ye-Xiong Tan
- International Cooperation Laboratory on Signal Transduction, Eastern Hepatobiliary Surgery Institute, the Naval Medical University, Shanghai, China; Laboratory of Signaling Regulation and Targeting Therapy of Liver Cancer, the Naval Medical University and Ministry of Education, Shanghai, China
| | - Li-Wei Dong
- National Center for Liver Cancer, the Third Affiliated Hospital of Naval Medical University, Shanghai, China; Laboratory of Signaling Regulation and Targeting Therapy of Liver Cancer, the Naval Medical University and Ministry of Education, Shanghai, China.
| | - Hong-Yang Wang
- National Center for Liver Cancer, the Third Affiliated Hospital of Naval Medical University, Shanghai, China; International Cooperation Laboratory on Signal Transduction, Eastern Hepatobiliary Surgery Institute, the Naval Medical University, Shanghai, China; Laboratory of Signaling Regulation and Targeting Therapy of Liver Cancer, the Naval Medical University and Ministry of Education, Shanghai, China; State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Hepato-biliary Tumor Biology, Shanghai, China.
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5
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Lee YJ, Shin KJ, Jang HJ, Ryu JS, Lee CY, Yoon JH, Seo JK, Park S, Lee S, Je AR, Huh YH, Kong SY, Kwon T, Suh PG, Chae YC. GPR143 controls ESCRT-dependent exosome biogenesis and promotes cancer metastasis. Dev Cell 2023; 58:320-334.e8. [PMID: 36800996 DOI: 10.1016/j.devcel.2023.01.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 10/17/2022] [Accepted: 01/26/2023] [Indexed: 02/18/2023]
Abstract
Exosomes transport a variety of macromolecules and modulate intercellular communication in physiology and disease. However, the regulation mechanisms that determine exosome contents during exosome biogenesis remain poorly understood. Here, we find that GPR143, an atypical GPCR, controls the endosomal sorting complex required for the transport (ESCRT)-dependent exosome biogenesis pathway. GPR143 interacts with HRS (an ESCRT-0 Subunit) and promotes its association to cargo proteins, such as EGFR, which subsequently enables selective protein sorting into intraluminal vesicles (ILVs) in multivesicular bodies (MVBs). GPR143 is elevated in multiple cancers, and quantitative proteomic and RNA profiling of exosomes in human cancer cell lines showed that the GPR143-ESCRT pathway promotes secretion of exosomes that carry unique cargo, including integrins signaling proteins. Through gain- and loss-of-function studies in mice, we show that GPR143 promotes metastasis by secreting exosomes and increasing cancer cell motility/invasion through the integrin/FAK/Src pathway. These findings provide a mechanism for regulating the exosomal proteome and demonstrate its ability to promote cancer cell motility.
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Affiliation(s)
- Yu Jin Lee
- Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Kyeong Jin Shin
- Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Hyun-Jun Jang
- Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Jin-Sun Ryu
- Division of Translational Science, Research Institute and Hospital, National Cancer Center, Goyang 10408, Republic of Korea
| | - Chae Young Lee
- Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Jong Hyuk Yoon
- Korea Brain Research Institute (KBRI), Daegu 41062, Republic of Korea
| | - Jeong Kon Seo
- Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Sabin Park
- Department of Biomedical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Semin Lee
- Department of Biomedical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - A Reum Je
- Electron Microscopy Research Center, Korea Basic Science Institute (KBSI), Cheongju 28119, Republic of Korea
| | - Yang Hoon Huh
- Electron Microscopy Research Center, Korea Basic Science Institute (KBSI), Cheongju 28119, Republic of Korea
| | - Sun-Young Kong
- Division of Translational Science, Research Institute and Hospital, National Cancer Center, Goyang 10408, Republic of Korea; Department of Cancer Biomedical Science, Graduate School of Cancer Science and Policy, National Cancer Center, Goyang 10408, Republic of Korea
| | - Taejoon Kwon
- Department of Biomedical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Pann-Ghill Suh
- Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea; Korea Brain Research Institute (KBRI), Daegu 41062, Republic of Korea.
| | - Young Chan Chae
- Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea.
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Lalnunthangi A, Dakpa G, Tiwari S. Multifunctional role of the ubiquitin proteasome pathway in phagocytosis. Prog Mol Biol Transl Sci 2023; 194:179-217. [PMID: 36631192 DOI: 10.1016/bs.pmbts.2022.06.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Phagocytosis is a specialized form of endocytosis where large cells and particles (>0.5μm) are engulfed by the phagocytic cells, and ultimately digested in the phagolysosomes. This process not only eliminates unwanted particles and pathogens from the extracellular sources, but also eliminates apoptotic cells within the body, and is critical for maintenance of tissue homeostasis. It is believed that both endocytosis and phagocytosis share common pathways after particle internalization, but specialized features and differences between these two routes of internalization are also likely. The recruitment and removal of each protein/particle during the maturation of endocytic/phagocytic vesicles has to be tightly regulated to ensure their timely action. Ubiquitin proteasome pathway (UPP), degrades unwanted proteins by post-translational modification of proteins with chains of conserved protein Ubiquitin (Ub), with subsequent recognition of Ub chains by the 26S proteasomes and substrate degradation by this protease. This pathway utilizes different Ub linkages to modify proteins to regulate protein-protein interaction, localization, and activity. Due to its vast number of targets, it is involved in many cellular pathways, including phagocytosis. This chapters describes the basic steps and signaling in phagocytosis and different roles that UPP plays at multiple steps in regulating phagocytosis directly, or through its interaction with other phagosomal proteins. How aberrations in UPP function affect phagocytosis and their association with human diseases, and how pathogens exploit this pathway for their own benefit is also discussed.
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Affiliation(s)
| | | | - Swati Tiwari
- School of Biotechnology, Jawaharlal Nehru University, New Delhi, India.
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Reilly A, Feechan A. The endosome as an effector target to mediate plant immunity? J Exp Bot 2023; 74:12-15. [PMID: 36563103 PMCID: PMC9786820 DOI: 10.1093/jxb/erac460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 11/21/2022] [Indexed: 06/17/2023]
Abstract
This article comments on: Liao W, Nielsen ME, Pedersen C, Xie W, Thordal-Christensen H. 2023. Barley endosomal MONENSIN SENSITIVITY1 is a target of the powdery mildew effector CSEP0162 and plays a role in plant immunity. Journal of Experimental Botany 74, 118–129.
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Affiliation(s)
- Aisling Reilly
- School of Agriculture and Food Science, University College Dublin, Belfield, Dublin 4, Ireland
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8
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Popescu MA, Patriche D, Dobrica MO, Pantazica AM, Flintoaca Alexandru PR, Rouillé Y, Popescu CI, Branza-Nichita N. Sac1 phosphatidylinositol 4-phosphate phosphatase is a novel host cell factor regulating hepatitis B virus particles assembly and release. FEBS J 2022; 289:7486-7499. [PMID: 35816160 DOI: 10.1111/febs.16575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 05/31/2022] [Accepted: 07/10/2022] [Indexed: 01/14/2023]
Abstract
The life-cycle of the Hepatitis B Virus (HBV), an enveloped DNA virus affecting the lives of more than 296 million chronicallyinfected people, is tightly dependent on the lipid metabolism of the host cell. Fatty acids and cholesterol are among the lipid factors with documented roles in regulating HBV replication and infection, respectively, but little is known about the phosphoinositide metabolism in these processes. In this study, we investigated the role of Sac1, a highly conserved phosphatidylinositol-4-phosphate (PI4P) phosphatase, with essential functions in phospholipid metabolism, in HBV assembly, and release. PI4P is one of the most abundant cellular phosphoinositide with complex functions at the level of the secretory pathway. Owing to the highly specific phosphatase activity toward PI4P, Sac1 controls the levels and restricts the localization of this lipid particularly at the trans-Golgi network, where it regulates sphingolipid synthesis, proteins sorting, and vesicles budding, by recruiting specific adaptor proteins. As a complete loss of Sac1 function compromises cell viability, in this work, we first developed and characterized several HBV replication-permissive cellular models with a moderate, transient, or stable downregulation of Sac1 expression. Our results show that Sac1 depletion in hepatic cells results in increased levels and redistribution of intracellular PI4P pools and impaired trafficking of the HBV envelope proteins to the endosomal vesicular network. Importantly, virus envelopment and release from these cells are significantly inhibited, revealing novel roles for Sac1, as a key host cell factor regulating morphogenesis of a DNA virus.
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Affiliation(s)
| | - David Patriche
- Institute of Biochemistry of the Romanian Academy, Bucharest, Romania
| | | | | | | | - Yves Rouillé
- Institut Pasteur de Lille, CHU Lille, U1019-UMR 9017-CIIL-Center for Infection and Immunity of Lille, University of Lille, CNRS, Inserm, France
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Ruf A, Oberkofler L, Robatzek S, Weiberg A. Spotlight on plant RNA-containing extracellular vesicles. Curr Opin Plant Biol 2022; 69:102272. [PMID: 35964451 DOI: 10.1016/j.pbi.2022.102272] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 06/29/2022] [Accepted: 07/04/2022] [Indexed: 06/15/2023]
Abstract
Extracellular vesicles (EVs) carrying RNA have attracted growing attention in plant cell biology. For a long time, EV release or uptake through the rigid plant cell wall was considered to be impossible and RNA outside cells to be unstable. Identified EV biomarkers have brought new insights into functional roles of EVs to transport their RNA cargo for systemic spread in plants and into plant-invading pathogens. RNA-binding proteins supposedly take over key functions in EV-mediated RNA secretion and transport, but the mechanisms of RNA sorting and EV translocation through the plant cell wall and plasma membrane are not understood. Characterizing the molecular players and the cellular mechanisms of plant RNA-containing EVs will create new knowledge in cell-to-cell and inter-organismal communication.
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Affiliation(s)
- Alessa Ruf
- LMU Munich Biocenter, Großhaderner Straße 4, 82152 Planegg-Martinsried, DE, Germany
| | - Lorenz Oberkofler
- LMU Munich Biocenter, Großhaderner Straße 4, 82152 Planegg-Martinsried, DE, Germany
| | - Silke Robatzek
- LMU Munich Biocenter, Großhaderner Straße 4, 82152 Planegg-Martinsried, DE, Germany
| | - Arne Weiberg
- LMU Munich Biocenter, Großhaderner Straße 4, 82152 Planegg-Martinsried, DE, Germany.
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Wu Q, Glitscher M, Tonnemacher S, Schollmeier A, Raupach J, Zahn T, Eberle R, Krijnse-Locker J, Basic M, Hildt E. Presence of Intact Hepatitis B Virions in Exosomes. Cell Mol Gastroenterol Hepatol 2023; 15:237-59. [PMID: 36184032 DOI: 10.1016/j.jcmgh.2022.09.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 09/23/2022] [Accepted: 09/23/2022] [Indexed: 02/21/2023]
Abstract
BACKGROUND & AIMS Hepatitis B virus (HBV) was identified as an enveloped DNA virus with a diameter of 42 nm. Multivesicular bodies play a central role in HBV egress and exosome biogenesis. In light of this, it was studied whether intact virions wrapped in exosomes are released by HBV-producing cells. METHODS Robust methods for efficient separation of exosomes from virions were established. Exosomes were subjected to limited detergent treatment for release of viral particles. Electron microscopy of immunogold labeled ultrathin sections of purified exosomes was performed for characterization of exosomal HBV. Exosome formation/release was affected by inhibitors or Crispr/Cas-mediated gene silencing. Infectivity/uptake of exosomal HBV was investigated in susceptible and non-susceptible cells. RESULTS Exosomes could be isolated from supernatants of HBV-producing cells, which are characterized by the presence of exosomal and HBV markers. These exosomal fractions could be separated from the fractions containing free virions. Limited detergent treatment of exosomes causes stepwise release of intact HBV virions and naked capsids. Inhibition of exosome morphogenesis impairs the release of exosome-wrapped HBV. Electron microscopy confirmed the presence of intact virions in exosomes. Moreover, the presence of large hepatitis B virus surface antigen on the surface of exosomes derived from HBV expressing cells was observed, which conferred exosome-encapsulated HBV initiating infection in susceptible cells in a , large hepatitis B virus surface antigen/Na+-taurocholate co-transporting polypeptide-dependent manner. The uptake of exosomal HBV with low efficiency was also observed in non-permissive cells. CONCLUSION These data indicate that a fraction of intact HBV virions can be released as exosomes. This reveals a so far not described release pathway for HBV.
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Abstract
Viruses are obligate intracellular pathogens that utilize cellular machinery for many aspects of their propagation and effective egress of virus particles from host cells is one important determinant of virus infectivity. Hijacking host cell processes applies in particular to the hepatitis B virus (HBV), as its DNA genome with about 3 kb in size is one of the smallest viral genomes known. HBV is a leading cause of liver disease and still displays one of the most successful pathogens in human populations worldwide. The extremely successful spread of this virus is explained by its efficient transmission strategies and its versatile particle types, including virions, empty envelopes, naked capsids and others. HBV exploits distinct host trafficking machineries to assemble and release its particle types including nucleocytoplasmic shuttling transport, secretory and exocytic pathways, the Endosomal Sorting Complexes Required for Transport pathway, and the autophagy pathway. Understanding how HBV uses and subverts host membrane trafficking systems offers the chance of obtaining new mechanistic insights into the regulation and function of this essential cellular processes. It can also help to identify potential targets for antiviral interventions. Here, I will provide an overview of HBV maturation, assembly, and budding, with a focus on recent advances, and will point out areas where questions remain that can benefit from future studies. Unless otherwise indicated, almost all presented knowledge was gained from cell culture-based, HBV in vitro -replication and in vitro -infection systems. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Reinhild Prange
- Department of Virology, University Medical Center of the Johannes Gutenberg University Mainz, Augustusplatz, Mainz, D-55131, Germany
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12
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Bayati A, Banks E, Han C, Luo W, Reintsch WE, Zorca CE, Shlaifer I, Del Cid Pellitero E, Vanderperre B, McBride HM, Fon EA, Durcan TM, McPherson PS. Rapid macropinocytic transfer of α-synuclein to lysosomes. Cell Rep 2022; 40:111102. [PMID: 35858558 DOI: 10.1016/j.celrep.2022.111102] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 05/10/2022] [Accepted: 06/22/2022] [Indexed: 12/01/2022] Open
Abstract
The nervous system spread of alpha-synuclein fibrils is thought to cause Parkinson's disease (PD) and other synucleinopathies; however, the mechanisms underlying internalization and cellular spread are enigmatic. Here, we use confocal and superresolution microscopy, subcellular fractionation, and electron microscopy (EM) of immunogold-labeled α-synuclein preformed fibrils (PFFs) to demonstrate that this form of the protein undergoes rapid internalization and is targeted directly to lysosomes in as little as 2 min. Uptake of PFFs is disrupted by macropinocytic inhibitors and circumvents classical endosomal pathways. Immunogold-labeled PFFs are seen at the highly curved inward edge of membrane ruffles, in newly formed macropinosomes, in multivesicular bodies and in lysosomes. While most fibrils remain in lysosomes, a portion is transferred to neighboring naive cells along with markers of exosomes. These data indicate that PFFs use a unique internalization mechanism as a component of cell-to-cell propagation.
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Affiliation(s)
- Armin Bayati
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, 3801 University Street, Montreal, QC H3A 2B4, Canada
| | - Emily Banks
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, 3801 University Street, Montreal, QC H3A 2B4, Canada
| | - Chanshuai Han
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, 3801 University Street, Montreal, QC H3A 2B4, Canada
| | - Wen Luo
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, 3801 University Street, Montreal, QC H3A 2B4, Canada
| | - Wolfgang E Reintsch
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, 3801 University Street, Montreal, QC H3A 2B4, Canada
| | - Cornelia E Zorca
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, 3801 University Street, Montreal, QC H3A 2B4, Canada
| | - Irina Shlaifer
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, 3801 University Street, Montreal, QC H3A 2B4, Canada
| | - Esther Del Cid Pellitero
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, 3801 University Street, Montreal, QC H3A 2B4, Canada
| | - Benoit Vanderperre
- Department of Biological Sciences, Université du Québec à Montréal, Montreal, QC, Canada
| | - Heidi M McBride
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, 3801 University Street, Montreal, QC H3A 2B4, Canada
| | - Edward A Fon
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, 3801 University Street, Montreal, QC H3A 2B4, Canada
| | - Thomas M Durcan
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, 3801 University Street, Montreal, QC H3A 2B4, Canada
| | - Peter S McPherson
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, 3801 University Street, Montreal, QC H3A 2B4, Canada.
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13
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Matsui T, Sakamaki Y, Nakashima S, Fukuda M. Rab39 and its effector UACA regulate basolateral exosome release from polarized epithelial cells. Cell Rep 2022; 39:110875. [PMID: 35649370 DOI: 10.1016/j.celrep.2022.110875] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 03/29/2022] [Accepted: 05/05/2022] [Indexed: 11/25/2022] Open
Abstract
Exosomes are small extracellular vesicles that originate from the intraluminal vesicles of multivesicular bodies (MVBs). We previously reported that polarized Madin-Darby canine kidney (MDCK) epithelial cells secrete two types of exosomes, apical and basolateral exosomes, from different MVBs. However, how these MVBs are selectively targeted to the apical or basolateral membrane remained unknown. Here, we analyze members of the Rab family small GTPases and show that different sets of Rabs mediate asymmetrical exosome release. Rab27, the best-known regulator of MVB transport for exosome release, is specifically but partially involved in apical exosome release, and Rab37, a close homolog of Rab27, is an additional apical exosome regulator. By contrast, Rab39 functions as a specific regulator of basolateral exosome release. Mechanistically, Rab39 interacts with its effector UACA, and UACA then recruits Lyspersin, a component of BLOC-1-related complex (BORC). Our findings suggest that the Rab39-UACA-BORC complex specifically mediates basolateral exosome release.
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Affiliation(s)
- Takahide Matsui
- Laboratory of Membrane Trafficking Mechanisms, Department of Integrative Life Sciences, Graduate School of Life Sciences, Tohoku University, Aobayama, Aoba-ku, Sendai, Miyagi 980-8578, Japan.
| | - Yuriko Sakamaki
- Microscopy Research Support Unit Research Core, Tokyo Medical and Dental University, Tokyo 113-8510, Japan
| | - Shumpei Nakashima
- Laboratory of Membrane Trafficking Mechanisms, Department of Integrative Life Sciences, Graduate School of Life Sciences, Tohoku University, Aobayama, Aoba-ku, Sendai, Miyagi 980-8578, Japan
| | - Mitsunori Fukuda
- Laboratory of Membrane Trafficking Mechanisms, Department of Integrative Life Sciences, Graduate School of Life Sciences, Tohoku University, Aobayama, Aoba-ku, Sendai, Miyagi 980-8578, Japan.
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14
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Wedemann L, Flomm FJ, Bosse JB. The unconventional way out-Egress of HCMV through multiviral bodies. Mol Microbiol 2022; 117:1317-1323. [PMID: 35607767 DOI: 10.1111/mmi.14946] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 05/18/2022] [Accepted: 05/21/2022] [Indexed: 12/14/2022]
Abstract
Human cytomegalovirus (HCMV) is a ubiquitous herpesvirus and the leading cause of congenital disabilities as well as a significant cause of disease in immunocompromised patients. The envelopment and egress of HCMV particles is an essential step of the viral life cycle as it determines viral spread and potentially tropism. Here we review the current literature on HCMV envelopment and egress with a particular focus on the role of virus-containing multivesicular body-like vesicles for virus egress and spread. We discuss the difficulties of determining the cellular provenance of these structures in light of viral redistribution of cellular marker proteins and provide potential paths to illuminate their genesis. Finally, we discuss how divergent egress pathways could result in virions of different tropisms.
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Affiliation(s)
- Linda Wedemann
- Centre for Structural Systems Biology, Hamburg, Germany.,Hannover Medical School, Institute of Virology, Hannover, Germany.,Cluster of Excellence RESIST (EXC 2155), Hannover Medical School, Hannover, Germany.,Leibniz-Institute of Virology, Hamburg, Germany
| | - Felix J Flomm
- Centre for Structural Systems Biology, Hamburg, Germany.,Hannover Medical School, Institute of Virology, Hannover, Germany.,Cluster of Excellence RESIST (EXC 2155), Hannover Medical School, Hannover, Germany.,Leibniz-Institute of Virology, Hamburg, Germany
| | - Jens B Bosse
- Centre for Structural Systems Biology, Hamburg, Germany.,Hannover Medical School, Institute of Virology, Hannover, Germany.,Cluster of Excellence RESIST (EXC 2155), Hannover Medical School, Hannover, Germany.,Leibniz-Institute of Virology, Hamburg, Germany
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15
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Garner RT, Weiss JA, Nie Y, Sullivan BP, Kargl CK, Drohan CJ, Kuang S, Stout J, Gavin TP. Effects of obesity and acute resistance exercise on skeletal muscle angiogenic communication pathways. Exp Physiol 2022; 107:906-918. [PMID: 35561231 DOI: 10.1113/ep090152] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 05/09/2022] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What are the central questions of this study? Do obesity and acute resistance exercise alter the regulation of muscle intercellular communication pathways consistent with inadequate compensatory angiogenesis in response to muscle loading present in individuals with obesity? What is the main finding and its importance? Obesity is associated with differences in both pro- and anti-angiogenic signaling consistent with lower muscle capillarization. Acute resistance exercise increases the release of skeletal muscle small extracellular vesicles independent of body mass. These results identify novel cellular factors associated with impaired angiogenesis in obesity and the positive effects of acute resistance exercise in lean and obese skeletal muscle. ABSTRACT Introduction Obesity (OB) impairs cell-to-cell communication signaling. Small extracellular vesicles (EVs), which includes exosomes, are released by skeletal muscle and participate in cell-to-cell communications including the regulation of angiogenesis. Resistance exercise (REx) increases muscle fiber size and capillarization. However, while obesity increases muscle fiber size, there is an inadequate increase in capillarization such that capillary density is reduced. It was hypothesized that REx induced angiogenic signaling and EV biogenesis would be lower with obesity. Methods Sedentary lean (LN) and individuals with obesity (OB) (n = 8/group) performed three sets of single leg, knee extension REx at 80% of maximum. Muscle biopsies were obtained at rest, 15 min, and 3 hr post-exercise and analyzed for angiogenic and EV biogenesis mRNA and protein. Results In OB, muscle fiber size was ∼20% greater and capillary density with type II fibers was ∼25% lower compared to LN (p<0.001) . In response to REx, increased vascular endothelial growth factor (VEGF) mRNA (pro-angiogenic) was similar (3-fold) between groups, while thrombospondin-1 (TSP-1) mRNA (anti-angiogenic) increased ∼2.5-fold in OB only (p = 0.010). miR-130a (pro-angiogenic) was ∼1.4-fold (p = 0.011) and miR-503 (anti-angiogenic) was ∼1.8-fold (p = 0.017) greater in OB compared to LN across all time points. In both groups acute REx decreased the EV surface protein Alix ∼50% consistent with the release of exosomes (p = 0.016). Conclusion Acute resistance exercise appears to induce the release of skeletal muscle small EVs independent of body mass. However, with obesity there is predominantly impaired angiogenic signaling consistent with inadequate angiogenesis in response to basal muscle hypertrophy. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Ron T Garner
- College of Science and Humanities, Husson University, ME, Bangor, IN, USA
| | - Jessica A Weiss
- Department of Health and Kinesiology and Max E. Wastl Human Performance Laboratory, Purdue University, West Lafayette, IN, USA
| | - Yaohui Nie
- Department of Health and Kinesiology and Max E. Wastl Human Performance Laboratory, Purdue University, West Lafayette, IN, USA.,Department of Animal Sciences, Purdue University, West Lafayette, IN, USA
| | - Brian P Sullivan
- Department of Health and Kinesiology and Max E. Wastl Human Performance Laboratory, Purdue University, West Lafayette, IN, USA
| | - Christopher K Kargl
- Department of Health and Kinesiology and Max E. Wastl Human Performance Laboratory, Purdue University, West Lafayette, IN, USA
| | - Cathal J Drohan
- School of Health and Human Performance, Dublin City University, Dublin, Ireland
| | - Shihuan Kuang
- Department of Health and Kinesiology and Max E. Wastl Human Performance Laboratory, Purdue University, West Lafayette, IN, USA.,Department of Animal Sciences, Purdue University, West Lafayette, IN, USA
| | - Julianne Stout
- Indiana University School of Medicine-West Lafayette, West Lafayette, IN, USA
| | - Timothy P Gavin
- Department of Health and Kinesiology and Max E. Wastl Human Performance Laboratory, Purdue University, West Lafayette, IN, USA
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16
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Glitscher M, Hildt E. Hepatitis E virus egress and beyond - the manifold roles of the viral ORF3 protein. Cell Microbiol 2021; 23:e13379. [PMID: 34272798 DOI: 10.1111/cmi.13379] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 06/18/2021] [Accepted: 07/06/2021] [Indexed: 11/30/2022]
Abstract
Although the hepatitis E virus represents an uprising threat to the global community by representing the commonest cause of an acute viral hepatitis worldwide, its life cycle is grossly understudied. Albeit HEV is a non-enveloped virus, its progeny is released as quasi-enveloped virions. Thus, the responsible accessory protein pORF3 gained rising attention in the past years. It mediates viral release via the exosomal route by targeting the viral capsid to the endosomal system, more precisely to multivesicular bodies. As this is followed by quasi-envelopment, pORF3 may in terms represent a substitute to a conventional envelope protein. This feature proofs to be rather unique with respect to other enteric viruses, although the protein's role in the viral life cycle seems to reach far beyond simply maintaining release of progeny viruses. How pORF3 affects viral morphogenesis, how it mediates efficient viral release and how it supports viral spread is summarised in this microreview. With this, we aim to shed light on functions of pORF3 to gain further insights in still enigmatic aspects of the HEV life cycle. TAKE AWAYS: HEV is released as exosome via multivesicular bodies Viral pORF3 mediates release via endosomal complexes required for transport pORF3 modulates various cellular processes in infected cells Elucidation of pORF3-related processes imply novel clinical strategies.
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Affiliation(s)
| | - Eberhard Hildt
- Department Virology, Paul-Ehrlich-Institut, Langen, Germany
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17
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Perrin P, Janssen L, Janssen H, van den Broek B, Voortman LM, van Elsland D, Berlin I, Neefjes J. Retrofusion of intralumenal MVB membranes parallels viral infection and coexists with exosome release. Curr Biol 2021:S0960-9822(21)00817-4. [PMID: 34237268 DOI: 10.1016/j.cub.2021.06.022] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 05/04/2021] [Accepted: 06/09/2021] [Indexed: 12/22/2022]
Abstract
The endosomal system constitutes a highly dynamic vesicle network used to relay materials and signals between the cell and its environment.1 Once internalized, endosomes gradually mature into late acidic compartments and acquire a multivesicular body (MVB) organization through invagination of the limiting membrane (LM) to form intraluminal vesicles (ILVs).2 Cargoes sequestered into ILVs can either be delivered to lysosomes for degradation or secreted following fusion of the MVB with the plasma membrane.3 It has been speculated that commitment to ILVs is not a terminal event, and that a return pathway exists, allowing “back-fusion” or “retrofusion” of intraluminal membranes to the LM.4 The existence of retrofusion as a way to support membrane equilibrium within the MVB has been widely speculated in various cell biological contexts, including exosome uptake5 and major histocompatibility complex class II (MHC class II) antigen presentation.6, 7, 8, 9 Given the small physical scale, retrofusion of ILVs cannot be measured with conventional techniques. To circumvent this, we designed a chemically tunable cell-based system to monitor retrofusion in real time. Using this system, we demonstrate that retrofusion occurs as part of the natural MVB lifestyle, with attributes parallel to those of viral infection. Furthermore, we find that retrofusion and exocytosis coexist in an equilibrium, implying that ILVs inert to retrofusion comprise a significant fraction of exosomes destined for secretion. MVBs thus contain three types of ILVs: those committed to lysosomal degradation, those retrofusing ILVs, and those subject to secretion in the form of exosomes. Video abstract
MVBs are complex organelles with intraluminal vesicles bound by the limiting membrane Intraluminal membranes are in a dynamic equilibrium with the limiting membrane Retrofusion of internal vesicles is controlled by processes used for viral fusion Exosomes arise from internal MVB vesicles not participating in retrofusion
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18
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Aydin Y, Koksal AR, Reddy V, Lin D, Osman H, Heidari Z, Rhadhi SM, Wimley WC, Parsi MA, Dash S. Extracellular Vesicle Release Promotes Viral Replication during Persistent HCV Infection. Cells 2021; 10:cells10050984. [PMID: 33922397 PMCID: PMC8146326 DOI: 10.3390/cells10050984] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 04/16/2021] [Accepted: 04/19/2021] [Indexed: 12/15/2022] Open
Abstract
Hepatitis C virus (HCV) infection promotes autophagic degradation of viral replicative intermediates for sustaining replication and spread. The excessive activation of autophagy can induce cell death and terminate infection without proper regulation. A prior publication from this laboratory showed that an adaptive cellular response to HCV microbial stress inhibits autophagy through beclin 1 degradation. The mechanisms of how secretory and degradative autophagy are regulated during persistent HCV infection is unknown. This study was performed to understand the mechanisms of viral persistence in the absence of degradative autophagy, which is essential for virus survival. Using HCV infection of a CD63-green fluorescence protein (CD63-GFP), labeled stable transfected Huh-7.5 cell, we found that autophagy induction at the early stage of HCV infection increased the degradation of CD63-GFP that favored virus replication. However, the late-stage of persistent HCV infection showed impaired autophagic degradation, leading to the accumulation of CD63-GFP. We found that impaired autophagic degradation promoted the release of extracellular vesicles and exosomes. The impact of blocking the release of extracellular vesicles (EVs) on virus survival was investigated in persistently infected cells and sub-genomic replicon cells. Our study illustrates that blocking EV and exosome release severely suppresses virus replication without effecting host cell viability. Furthermore, we found that blocking EV release triggers interferon lambda 1 secretion. These findings suggest that the release of EVs is an innate immune escape mechanism that promotes persistent HCV infection. We propose that inhibition of extracellular vesicle release can be explored as a potential antiviral strategy for the treatment of HCV and other emerging RNA viruses.
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Affiliation(s)
- Yucel Aydin
- Department of Pathology and Laboratory Medicine, Tulane University Health Sciences Center, New Orleans, LA 70112, USA; (Y.A.); (V.R.); (D.L.); (H.O.); (S.M.R.)
| | - Ali Riza Koksal
- Department of Medicine, Division of Gastroenterology and Hepatology, Tulane University Health Sciences Center, New Orleans, LA 70112, USA; (A.R.K.); (M.A.P.)
| | - Venu Reddy
- Department of Pathology and Laboratory Medicine, Tulane University Health Sciences Center, New Orleans, LA 70112, USA; (Y.A.); (V.R.); (D.L.); (H.O.); (S.M.R.)
| | - Dong Lin
- Department of Pathology and Laboratory Medicine, Tulane University Health Sciences Center, New Orleans, LA 70112, USA; (Y.A.); (V.R.); (D.L.); (H.O.); (S.M.R.)
| | - Hanadi Osman
- Department of Pathology and Laboratory Medicine, Tulane University Health Sciences Center, New Orleans, LA 70112, USA; (Y.A.); (V.R.); (D.L.); (H.O.); (S.M.R.)
| | - Zahra Heidari
- Department of Chemical and Biomedical Engineering, Tulane University, New Orleans, LA 70112, USA;
| | - Sadeq Mutlab Rhadhi
- Department of Pathology and Laboratory Medicine, Tulane University Health Sciences Center, New Orleans, LA 70112, USA; (Y.A.); (V.R.); (D.L.); (H.O.); (S.M.R.)
| | - William C Wimley
- Department of Biochemistry and Molecular Biology, Tulane University Health Sciences Center, New Orleans, LA 70112, USA;
| | - Mansour A Parsi
- Department of Medicine, Division of Gastroenterology and Hepatology, Tulane University Health Sciences Center, New Orleans, LA 70112, USA; (A.R.K.); (M.A.P.)
| | - Srikanta Dash
- Department of Pathology and Laboratory Medicine, Tulane University Health Sciences Center, New Orleans, LA 70112, USA; (Y.A.); (V.R.); (D.L.); (H.O.); (S.M.R.)
- Department of Medicine, Division of Gastroenterology and Hepatology, Tulane University Health Sciences Center, New Orleans, LA 70112, USA; (A.R.K.); (M.A.P.)
- Southeast Louisiana Veterans Health Care System, 2400 Canal Street, New Orleans, LA 70119, USA
- Correspondence: ; Tel.: +1-504-988-2519; Fax: +1-504-988-7389
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Burillo J, Fernández-Rhodes M, Piquero M, López-Alvarado P, Menéndez JC, Jiménez B, González-Blanco C, Marqués P, Guillén C, Benito M. Human amylin aggregates release within exosomes as a protective mechanism in pancreatic β cells: Pancreatic β-hippocampal cell communication. Biochim Biophys Acta Mol Cell Res 2021; 1868:118971. [PMID: 33515645 DOI: 10.1016/j.bbamcr.2021.118971] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Revised: 01/19/2021] [Accepted: 01/24/2021] [Indexed: 12/19/2022]
Abstract
Pancreatic β cells are essential in the maintenance of glucose homeostasis during the progression to type 2 Diabetes Mellitus (T2DM), generating compensatory hyperinsulinemia to counteract insulin resistance. It is well known, that throughout the process there is an increased mTORC1 signaling pathway, with an impairment in different quality control systems including ubiquitin-proteasome system and autophagy. In addition, under this situation, pancreatic β cells start to accumulate amylin protein (IAPP) in aggregates, and this accumulation contributes to the failure of autophagy, damaging different organelles such as plasma membrane, endoplasmic reticulum, mitochondria, and others. Here, we report that IAPP can be incorporated to multivesicular bodies (MVB) and secreted into exosomes, a mechanism responsible for the exportation of these toxic aggregates as vehicles of cell to cell communication. On this regard, we have demonstrated that the exosomes bearing toxic hIAPP released from pancreatic β cells are capable to induce hyperactivation of mTORC1 signaling, a failure in the autophagic cellular quality control, and favor pro-fission status of the mitochondrial dynamics in hippocampal cells. In summary, our results show that harmful accumulation of hIAPP in pancreatic β cells may be detoxified by the release of exosomes, which may be captured by endocytosis mechanism damaging neuronal hippocampal cells, which suggest an underlying molecular mechanism to the link between type 2 diabetes and neurodegenerative diseases.
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Affiliation(s)
- J Burillo
- Department of Biochemistry and molecular Biology, Complutense University, Madrid, Spain; Centro de Investigación Biomédica en Red (CIBER) de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Madrid, Spain; MOIR2: Mechanisms of Insulin Resistance, General Direction of Universities and Investigation (CCMM), Spain
| | - M Fernández-Rhodes
- Department of Biochemistry and molecular Biology, Complutense University, Madrid, Spain
| | - M Piquero
- Department of Organic Chemistry, Complutense University, Madrid, Spain
| | - P López-Alvarado
- Department of Organic Chemistry, Complutense University, Madrid, Spain
| | - J C Menéndez
- Department of Organic Chemistry, Complutense University, Madrid, Spain
| | - B Jiménez
- Department of Biochemistry and molecular Biology, Complutense University, Madrid, Spain; Centro de Investigación Biomédica en Red (CIBER) de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Madrid, Spain
| | - C González-Blanco
- Department of Biochemistry and molecular Biology, Complutense University, Madrid, Spain
| | - P Marqués
- Department of Biochemistry and molecular Biology, Complutense University, Madrid, Spain
| | - C Guillén
- Department of Biochemistry and molecular Biology, Complutense University, Madrid, Spain; Centro de Investigación Biomédica en Red (CIBER) de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Madrid, Spain; MOIR2: Mechanisms of Insulin Resistance, General Direction of Universities and Investigation (CCMM), Spain.
| | - M Benito
- Department of Biochemistry and molecular Biology, Complutense University, Madrid, Spain; Centro de Investigación Biomédica en Red (CIBER) de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Madrid, Spain; MOIR2: Mechanisms of Insulin Resistance, General Direction of Universities and Investigation (CCMM), Spain
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20
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Lin S, Meng T, Huang H, Zhuang H, He Z, Yang H, Feng D. Molecular machineries and physiological relevance of ER-mediated membrane contacts. Theranostics 2021; 11:974-995. [PMID: 33391516 PMCID: PMC7738843 DOI: 10.7150/thno.51871] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 10/22/2020] [Indexed: 02/06/2023] Open
Abstract
Membrane contact sites (MCSs) are defined as regions where two organelles are closely apposed, and most MCSs associated with each other via protein-protein or protein-lipid interactions. A number of key molecular machinery systems participate in mediating substance exchange and signal transduction, both of which are essential processes in terms of cellular physiology and pathophysiology. The endoplasmic reticulum (ER) is the largest reticulum network within the cell and has extensive communication with other cellular organelles, including the plasma membrane (PM), mitochondria, Golgi, endosomes and lipid droplets (LDs). The contacts and reactions between them are largely mediated by various protein tethers and lipids. Ions, lipids and even proteins can be transported between the ER and neighboring organelles or recruited to the contact site to exert their functions. This review focuses on the key molecules involved in the formation of different contact sites as well as their biological functions.
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21
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Roggenhofer E, Muller S, Santarnecchi E, Melie-Garcia L, Wiest R, Kherif F, Draganski B. Remodeling of brain morphology in temporal lobe epilepsy. Brain Behav 2020; 10:e01825. [PMID: 32945137 PMCID: PMC7667340 DOI: 10.1002/brb3.1825] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 08/10/2020] [Accepted: 08/14/2020] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Mesial temporal lobe epilepsy (TLE) is one of the most widespread neurological network disorders. Computational anatomy MRI studies demonstrate a robust pattern of cortical volume loss. Most statistical analyses provide information about localization of significant focal differences in a segregationist way. Multivariate Bayesian modeling provides a framework allowing inferences about inter-regional dependencies. We adopt this approach to answer following questions: Which structures within a pattern of dynamic epilepsy-associated brain anatomy reorganization best predict TLE pathology. Do these structures differ between TLE subtypes? METHODS We acquire clinical and MRI data from TLE patients with and without hippocampus sclerosis (n = 128) additional to healthy volunteers (n = 120). MRI data were analyzed in the computational anatomy framework of SPM12 using classical mass-univariate analysis followed by multivariate Bayesian modeling. RESULTS After obtaining TLE-associated brain anatomy pattern, we estimate predictive power for disease and TLE subtypes using Bayesian model selection and comparison. We show that ipsilateral para-/hippocampal regions contribute most to disease-related differences between TLE and healthy controls independent of TLE laterality and subtype. Prefrontal cortical changes are more discriminative for left-sided TLE, whereas thalamus and temporal pole for right-sided TLE. The presence of hippocampus sclerosis was linked to stronger involvement of thalamus and temporal lobe regions; frontoparietal involvement was predominant in absence of sclerosis. CONCLUSIONS Our topology inferences on brain anatomy demonstrate a differential contribution of structures within limbic and extralimbic circuits linked to main effects of TLE and hippocampal sclerosis. We interpret our results as evidence for TLE-related spatial modulation of anatomical networks.
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Affiliation(s)
- Elisabeth Roggenhofer
- Neurology Department, Department of Clinical Neuroscience, HUG, University Hospitals and Faculty of Medicine Geneva, Geneva, Switzerland.,Department of Clinical Neurosciences, LREN, CHUV, University of Lausanne, Lausanne, Switzerland
| | - Sandrine Muller
- Department of Clinical Neurosciences, LREN, CHUV, University of Lausanne, Lausanne, Switzerland
| | - Emiliano Santarnecchi
- Berenson-Allen Center for Non-Invasive Brain Stimulation, Cognitive Neurology Department, Beth Israel Medical Center, Harvard Medical School, Boston, MA, USA.,Siena Brain Investigation and Neuromodulation Lab, Department of Medicine, Surgery and Neuroscience, University of Siena, Siena, Italy
| | - Lester Melie-Garcia
- Department of Clinical Neurosciences, LREN, CHUV, University of Lausanne, Lausanne, Switzerland.,Applied Signal Processing Group, Swiss Federal Institute of Technology Lausanne (EPFL), Lausanne, Switzerland
| | - Roland Wiest
- Support Center for Advanced Neuroimaging, Institute for Diagnostic and Interventional Neuroradiology, University Hospital Inselspital, University of Bern, Bern, Switzerland
| | - Ferath Kherif
- Department of Clinical Neurosciences, LREN, CHUV, University of Lausanne, Lausanne, Switzerland
| | - Bogdan Draganski
- Department of Clinical Neurosciences, LREN, CHUV, University of Lausanne, Lausanne, Switzerland.,Department of Neurology, Max-Planck-Institute for Human Cognitive and Brain Sciences, Max Planck Society, Leipzig, Germany
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22
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Tavares LA, de Carvalho JV, Costa CS, Silveira RM, de Carvalho AN, Donadi EA, daSilva LLP. Two Functional Variants of AP-1 Complexes Composed of either γ2 or γ1 Subunits Are Independently Required for Major Histocompatibility Complex Class I Downregulation by HIV-1 Nef. J Virol 2020; 94:e02039-19. [PMID: 31915283 DOI: 10.1128/JVI.02039-19] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 01/01/2020] [Indexed: 11/20/2022] Open
Abstract
The HIV-1 accessory protein Nef downregulates the cell surface expression of major histocompatibility complex class I (MHC-I) molecules to facilitate virus spreading. The Nef-induced downregulation of MHC-I molecules such as HLA-A requires the clathrin adaptor protein 1 (AP-1) complex. The cooperative interaction of Nef, AP-1, and the cytosolic tail (CT) of HLA-A leads to a redirection of HLA-A targeting from the trans-Golgi network (TGN) to lysosomes for degradation. Although the γ-adaptin subunit of AP-1 has two distinct isoforms (γ1 and γ2), which may form two AP-1 complex variants, so far, only the importance of AP-1γ1 in MHC-I downregulation by Nef has been investigated. Here, we report that the AP-1γ2 isoform also participates in this process. We found that AP-1γ2 forms a complex with Nef and HLA-A2_CT and that this interaction depends on the Y320 residue in HLA-A2_CT and Nef expression. Moreover, Nef targets AP-1γ1 and AP-1γ2 to different compartments in T cells, and the depletion of either AP-1 variant impairs the Nef-mediated reduction of total endogenous HLA-A levels and rescues HLA-A levels on the cell surface. Finally, immunofluorescence and immunoelectron microscopy analyses reveal that the depletion of γ2 in T cells compromises both the Nef-mediated retention of HLA-A molecules in the TGN and targeting to multivesicular bodies/late endosomes. Altogether, these results show that in addition to AP-1γ1, Nef also requires the AP-1γ2 variant for efficient MHC-I downregulation.IMPORTANCE HIV-1 Nef mediates evasion of the host immune system by inhibiting MHC-I surface presentation of viral antigens. To achieve this goal, Nef modifies the intracellular trafficking of MHC-I molecules in several ways. Despite being the subject of intense study, the molecular details underlying these modifications are not yet fully understood. Adaptor protein 1 (AP-1) plays an essential role in the Nef-mediated downregulation of MHC-I molecules such as HLA-A in different cell types. However, AP-1 has two functionally distinct variants composed of either γ1 or γ2 subunit isoforms. Because previous studies on the role of AP-1 in MHC-I downregulation by Nef focused on AP-1γ1, an important open question is the participation of AP-1γ2 in this process. Here, we show that AP-1γ2 is also essential for Nef-mediated depletion of surface HLA-A molecules in T cells. Our results indicate that Nef hijacks AP-1γ2 to modify HLA-A intracellular transport, redirecting these proteins to lysosomes for degradation.
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23
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Haseeb A, Bai X, Vistro WA, Tarique I, Chen H, Yang P, Gandahi NS, Iqbal A, Huang Y, Chen Q. Characterization of in vivo autophagy during avian spermatogenesis1. Poult Sci 2019; 98:5089-5099. [PMID: 31198935 DOI: 10.3382/ps/pez320] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Accepted: 05/25/2019] [Indexed: 12/11/2022] Open
Abstract
Spermatogenesis is a complex cellular process that includes many subcellular events that are essential for the production of healthy spermatozoa. Autophagy is a physiological process that plays a significant role in the process of spermatogenesis; however, autophagy during avian spermatogenesis has not yet been reported. In the current study, we characterized in vivo autophagy throughout the process of domestic fowl spermatogenesis. Autophagy-specific markers, including microtubule-associated protein light chain 3 (LC3), sequestosome 1 (p62), and autophagy-related 7 (Atg7), were used to confirm the occurrence of autophagy in testicular germ cells. The protein expression of Atg7, LC3, and p62 in domestic fowl testes was confirmed by Western blotting. The immunohistochemical staining indicated a strong localization of LC3 and Atg7 within spermiogenic cells (intermediate and late spermatids) and primary spermatocytes. However, poorly expressed in cells (spermatogonia) that were located near the basement membrane. The immunofluorescence staining results showed the opposite tendency for LC3 and p62. LC3 was more strongly localized within the elongated spermatids, while p62 was strongly localized within the early spermatids. Moreover, the ultrastructural components of autophagy were revealed by transmission electron microscopy. Well-developed autophagosomes and multivesicular bodies were found to be prominent in primary spermatocytes (zygotene and pachytene) and spermiogenic cells. Furthermore, other vesicular structures, such as early endosomes and amphisomes, were also observed during spermatogenesis. The above findings collectively suggest that autophagy is active during spermatogenesis and that the level of autophagy increases from the basal to the luminal regions of the seminiferous tubules of domestic fowl testes. We propose that autophagic pathways may be involved in multiple functions to sustain spermatogenesis.
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Affiliation(s)
- A Haseeb
- Ministry of Education (MOE) Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Jiangsu Province 210095, China.,Faculty of Veterinary and Animal Sciences, University of Poonch Rawalakot, Azad Kashmir 12350, Pakistan
| | - X Bai
- Ministry of Education (MOE) Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Jiangsu Province 210095, China
| | - W A Vistro
- Ministry of Education (MOE) Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Jiangsu Province 210095, China
| | - I Tarique
- Ministry of Education (MOE) Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Jiangsu Province 210095, China
| | - H Chen
- Ministry of Education (MOE) Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Jiangsu Province 210095, China
| | - P Yang
- Ministry of Education (MOE) Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Jiangsu Province 210095, China
| | - N S Gandahi
- Ministry of Education (MOE) Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Jiangsu Province 210095, China
| | - A Iqbal
- Ministry of Education (MOE) Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Jiangsu Province 210095, China
| | - Y Huang
- Ministry of Education (MOE) Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Jiangsu Province 210095, China
| | - Q Chen
- Ministry of Education (MOE) Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Jiangsu Province 210095, China
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24
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Han Q, Lv L, Wei J, Lei X, Lin H, Li G, Cao J, Xie J, Yang W, Wu S, You J, Lu J, Liu P, Min J. Vps4A mediates the localization and exosome release of β-catenin to inhibit epithelial-mesenchymal transition in hepatocellular carcinoma. Cancer Lett 2019; 457:47-59. [PMID: 31059752 DOI: 10.1016/j.canlet.2019.04.035] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2018] [Revised: 04/05/2019] [Accepted: 04/26/2019] [Indexed: 12/20/2022]
Abstract
We previously reported that Vps4A acted as a tumor suppressor by influencing the microRNA profiles of exosomes and their parental cells in hepatocellular carcinoma (HCC). However, the underlying mechanism and if Vps4A contributes to sorting proteins into exosomes are not well known. Here, we performed mass spectrometry analysis of the immunoprecipitated Vps4A complex and confirmed that Vps4A was associated with β-catenin and CHMP4B. Through this interaction, Vps4A promoted the plasma membrane (PM) localization and exosome release of β-catenin. Silencing Vps4A or CHMP4B decreased the PM localization and exosome sorting of β-catenin. Vps4A overexpression decreased β-catenin signaling pathway and inhibited epithelial-mesenchymal transition (EMT) and motility of HCC cells. And, silencing Vps4A or CHMP4B promoted EMT in HCC. Furthermore, the expression of Vps4A was significantly related to that of several EMT markers in HCC tissues and the level of exosomal β-catenin in patients with metastatic HCC was significantly lower compared to that of control patients. In conclusion, through the interaction with CHMP4B and β-catenin, Vps4A regulates the PM localization and exosome sorting of β-catenin, consequently decreases β-catenin signaling, and thereby inhibits EMT and metastasis in HCC.
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Affiliation(s)
- Qingfang Han
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-sen University, Guangzhou, 510120, China; Department of Hepatobiliary Surgery, Sun Yat-sen Memorial Hospital, Guangzhou, 510120, China
| | - Lihong Lv
- Clinical Trial Institution of Pharmaceuticals, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, 510120, China
| | - Jinxing Wei
- Department of Hepatobiliary Surgery, Sun Yat-sen Memorial Hospital, Guangzhou, 510120, China
| | - Xin Lei
- Department of Thyroid and Breast Surgery, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, 510080, China
| | - Haoming Lin
- Department of Hepatobiliary Surgery, Sun Yat-sen Memorial Hospital, Guangzhou, 510120, China
| | - Guolin Li
- Department of Hepatobiliary Surgery, Sun Yat-sen Memorial Hospital, Guangzhou, 510120, China
| | - Jun Cao
- Department of Hepatobiliary Surgery, Sun Yat-sen Memorial Hospital, Guangzhou, 510120, China
| | - Jiyan Xie
- Department of Hepatobiliary Surgery, Sun Yat-sen Memorial Hospital, Guangzhou, 510120, China
| | - Weibang Yang
- Department of Hepatobiliary Surgery, Sun Yat-sen Memorial Hospital, Guangzhou, 510120, China
| | - Shaobin Wu
- Department of Hepatobiliary Surgery, Sun Yat-sen Memorial Hospital, Guangzhou, 510120, China
| | - Jia You
- Laboratory of Pharmacology and Toxicology, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, China
| | - Jing Lu
- Laboratory of Pharmacology and Toxicology, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, China
| | - Peiqing Liu
- Laboratory of Pharmacology and Toxicology, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, China.
| | - Jun Min
- Department of Hepatobiliary Surgery, Sun Yat-sen Memorial Hospital, Guangzhou, 510120, China.
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25
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Valcz G, Buzás EI, Kittel Á, Krenács T, Visnovitz T, Spisák S, Török G, Homolya L, Zsigrai S, Kiszler G, Antalffy G, Pálóczi K, Szállási Z, Szabó V, Sebestyén A, Solymosi N, Kalmár A, Dede K, Lőrincz P, Tulassay Z, Igaz P, Molnár B. En bloc release of MVB-like small extracellular vesicle clusters by colorectal carcinoma cells. J Extracell Vesicles 2019; 8:1596668. [PMID: 31007874 PMCID: PMC6461071 DOI: 10.1080/20013078.2019.1596668] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Revised: 03/04/2019] [Accepted: 03/12/2019] [Indexed: 12/24/2022] Open
Abstract
Small extracellular vesicles (EVs) are membrane enclosed structures that are usually released from cells upon exocytosis of multivesicular bodies (MVBs) as a collection of separate, free EVs. In this study, we analysed paraffin embedded sections of archived human colorectal cancer samples. We studied 3D reconstructions of confocal microscopic images complemented by HyVolution and STED imaging. Unexpectedly, we found evidence that large, MVB-like aggregates of ALIX/CD63 positive EV clusters were released en bloc by migrating tumour cells. These structures were often captured with partial or complete extra-cytoplasmic localization at the interface of the plasma membrane of the tumour cell and the stroma. Their diameter ranged between 0.62 and 1.94 μm (mean±S.D.: 1.17 ± 0.34 μm). High-resolution 3D reconstruction showed that these extracellular MVB-like EV clusters were composed of distinguishable internal particles of small EV size (mean±S.D.: 128.96 ± 16.73 nm). In vitro, HT29 colorectal cancer cells also showed the release of similar structures as confirmed by immunohistochemistry and immune electron microscopy. Our results provide evidence for an en bloc transmission of MVB-like EV clusters through the plasma membrane. Immunofluorescent-based detection of the MVB like small EV clusters in archived pathological samples may represent a novel and unique opportunity which enables analysis of EV release in situ in human tissues.
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Affiliation(s)
- Gábor Valcz
- Molecular Medicine Research Group, Hungarian Academy of Sciences and Semmelweis University, Budapest, Hungary.,2nd Department of Medicine, Semmelweis University, Budapest, Hungary
| | - Edit I Buzás
- Department of Genetics, Cell- and Immunobiology, Semmelweis University, Budapest, Hungary.,MTA-SE Immune-Proteogenomics Extracellular Vesicle Research Group, Hungarian Academy of Sciences, Budapest, Hungary
| | - Ágnes Kittel
- Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | - Tibor Krenács
- 1st Department of Pathology and Experimental Cancer Research, Semmelweis University, Budapest, Hungary
| | - Tamás Visnovitz
- Department of Genetics, Cell- and Immunobiology, Semmelweis University, Budapest, Hungary.,MTA-SE Immune-Proteogenomics Extracellular Vesicle Research Group, Hungarian Academy of Sciences, Budapest, Hungary
| | - Sándor Spisák
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, USA
| | - György Török
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
| | - László Homolya
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
| | - Sára Zsigrai
- 2nd Department of Medicine, Semmelweis University, Budapest, Hungary
| | - Gábor Kiszler
- Department of Image Analysis, 3DHISTECH Ltd, Budapest, Hungary
| | - Géza Antalffy
- Department of Image Analysis, 3DHISTECH Ltd, Budapest, Hungary
| | - Krisztina Pálóczi
- Department of Genetics, Cell- and Immunobiology, Semmelweis University, Budapest, Hungary
| | - Zoltán Szállási
- Computational Health Informatics Program (CHIP), Boston Children's Hospital and Harvard Medical School, Boston, USA
| | - Vanessza Szabó
- Department of Image Analysis, 3DHISTECH Ltd, Budapest, Hungary
| | - Anna Sebestyén
- 1st Department of Pathology and Experimental Cancer Research, Semmelweis University, Budapest, Hungary
| | - Norbert Solymosi
- Centre for Bioinformatics, University of Veterinary Medicine, Budapest, Hungary
| | - Alexandra Kalmár
- Molecular Medicine Research Group, Hungarian Academy of Sciences and Semmelweis University, Budapest, Hungary.,2nd Department of Medicine, Semmelweis University, Budapest, Hungary
| | - Kristóf Dede
- Department of General Surgery and Surgical Oncology, Uzsoki Teaching Hospital, Budapest, Hungary
| | - Péter Lőrincz
- Department of Anatomy, Cell and Developmental Biology, Eötvös Loránd University, Budapest, Hungary
| | - Zsolt Tulassay
- Molecular Medicine Research Group, Hungarian Academy of Sciences and Semmelweis University, Budapest, Hungary.,2nd Department of Medicine, Semmelweis University, Budapest, Hungary
| | - Péter Igaz
- Molecular Medicine Research Group, Hungarian Academy of Sciences and Semmelweis University, Budapest, Hungary.,2nd Department of Medicine, Semmelweis University, Budapest, Hungary
| | - Béla Molnár
- Molecular Medicine Research Group, Hungarian Academy of Sciences and Semmelweis University, Budapest, Hungary.,2nd Department of Medicine, Semmelweis University, Budapest, Hungary
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26
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Tabernero L, Woodman P. Dissecting the role of His domain protein tyrosine phosphatase/PTPN23 and ESCRTs in sorting activated epidermal growth factor receptor to the multivesicular body. Biochem Soc Trans 2018; 46:1037-46. [PMID: 30190330 DOI: 10.1042/BST20170443] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 05/31/2018] [Accepted: 07/31/2018] [Indexed: 02/06/2023]
Abstract
Sorting of activated epidermal growth factor receptor (EGFR) into intraluminal vesicles (ILVs) within the multivesicular body (MVB) is an essential step during the down-regulation of the receptor. The machinery that drives EGFR sorting attaches to the cytoplasmic face of the endosome and generates vesicles that bud into the endosome lumen, but somehow escapes encapsulation itself. This machinery is termed the ESCRT (endosomal sorting complexes required for transport) pathway, a series of multi-protein complexes and accessory factors first identified in yeast. Here, we review the yeast ESCRT pathway and describe the corresponding components in mammalian cells that sort EGFR. One of these is His domain protein tyrosine phosphatase (HD-PTP/PTPN23), and we review the interactions involving HD-PTP and ESCRTs. Finally, we describe a working model for how this ESCRT pathway might overcome the intrinsic topographical problem of EGFR sorting to the MVB lumen.
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27
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Saha N, Dutta S, Datta SP, Sarkar S. The minimal ESCRT machinery of Giardia lamblia has altered inter-subunit interactions within the ESCRT-II and ESCRT-III complexes. Eur J Cell Biol 2017; 97:44-62. [PMID: 29224850 DOI: 10.1016/j.ejcb.2017.11.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Revised: 11/29/2017] [Accepted: 11/30/2017] [Indexed: 11/19/2022] Open
Abstract
The ESCRT pathway functions at different subcellular membranes to induce their negative curvature, and it has been largely characterized in model eukaryotes belonging to Opisthokonta. But searches of the genomes of many nonopisthokonts belonging to various supergroups indicate that some of them may harbour fewer ESCRT components. Of the genomes explored thus far, one of the most minimal set of ESCRT components was identified in the human pathogen Giardia lamblia, which belongs to Excavata. Here we report that an ESCRT-mediated pathway most likely operates at the peripheral vesicles, which are located at the cell periphery and the bare zone of this protist. Functional comparison of all the identified putative giardial ESCRT components, with the corresponding well-characterized orthologues from Saccharomyces cerevisiae, indicated that only some of the ESCRT components could functionally substitute for the corresponding yeast proteins. While GlVps25, GlVps2, and all three paralogues of GlVps4, tested positive in functional complementation assays, GlVps22, GlVps20, and GlVps24 did not. Binary interactions of either GlVps22 or GlVps25, with other ESCRT-II components from Giardia or yeast indicate that the giardial Vps36 orthologue is either completely missing or highly diverged. Interactions within the giardial ESCRT-III components also differ from those in yeast; while GlVps46a interacts preferentially with Vps24 compared to Vps2, GlVps46b, like the yeast orthologue, interacts with both.
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Affiliation(s)
- Nabanita Saha
- Department of Biochemistry, Bose Institute, P 1/12 CIT Road Scheme VII M, Kolkata 700054, West Bengal, India.
| | - Somnath Dutta
- Department of Biochemistry, Bose Institute, P 1/12 CIT Road Scheme VII M, Kolkata 700054, West Bengal, India.
| | - Shankari P Datta
- Department of Biochemistry, Bose Institute, P 1/12 CIT Road Scheme VII M, Kolkata 700054, West Bengal, India.
| | - Srimonti Sarkar
- Department of Biochemistry, Bose Institute, P 1/12 CIT Road Scheme VII M, Kolkata 700054, West Bengal, India.
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28
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Pečenková T, Pleskot R, Žárský V. Subcellular Localization of Arabidopsis Pathogenesis-Related 1 (PR1) Protein. Int J Mol Sci 2017; 18:E825. [PMID: 28406455 PMCID: PMC5412409 DOI: 10.3390/ijms18040825] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 04/02/2017] [Accepted: 04/07/2017] [Indexed: 12/15/2022] Open
Abstract
The Arabidopsisthaliana pathogenesis-related 1 (PR1) is an important defense protein, so far it has only been detected in extracellular space and its subcellular sorting and transport remain unexplained. Using a green fluorescent protein (GFP) tagged full length, as well as a C-terminus truncated version of PR1, we observed that when expressed ectopically in Nicotiana benthamiana leaves, PR1 co-localizes only partially with Golgi markers, and much more prominently with the late endosome (LE)/multivesicular body (MVB) FYVE marker. The C-truncated version PR1ΔC predominantly localized to the endoplasmic reticulum (ER). The same localizations were found for stable Arabidopsis transformants with expression of PR1 and PR1ΔC driven by the native promoter. We conclude that the A. thaliana PR1 (AtPR1) undergoes an unconventional secretion pathway, starting from the C-terminus-dependent sorting from the ER, and utilizing further transportation via phosphatidyl-inositol-3-phosphate (PI(3)P) positive LE/MVB-like vesicles. The homology model of the PR1 structure shows that the cluster of positively charged amino acid residues (arginines 60, 67, 137, and lysine 135) could indeed interact with negatively charged phospholipids of cellular membranes. It remains to be resolved whether Golgi and LE/MVB localization reflects an alternative sorting or trafficking succession, and what the role of lipid interactions in it will be.
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Affiliation(s)
- Tamara Pečenková
- Laboratory of Cell Biology, Institute of Experimental Botany, Academy of Sciences of the Czech Republic, Rozvojova 263, 165 02 Prague 6, Czech Republic.
| | - Roman Pleskot
- Laboratory of Cell Biology, Institute of Experimental Botany, Academy of Sciences of the Czech Republic, Rozvojova 263, 165 02 Prague 6, Czech Republic.
| | - Viktor Žárský
- Laboratory of Cell Morphogenesis, Department of Experimental Plant Biology, Faculty of Science, Charles University in Prague, Vinicna 5, 128 44 Prague 2, Czech Republic.
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29
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Pečenková T, Pleskot R, Žárský V. Subcellular Localization of Arabidopsis Pathogenesis-Related 1 (PR1) Protein. Int J Mol Sci 2017. [PMID: 28406455 DOI: 10.3390/ijms1804082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/09/2023] Open
Abstract
The Arabidopsisthaliana pathogenesis-related 1 (PR1) is an important defense protein, so far it has only been detected in extracellular space and its subcellular sorting and transport remain unexplained. Using a green fluorescent protein (GFP) tagged full length, as well as a C-terminus truncated version of PR1, we observed that when expressed ectopically in Nicotiana benthamiana leaves, PR1 co-localizes only partially with Golgi markers, and much more prominently with the late endosome (LE)/multivesicular body (MVB) FYVE marker. The C-truncated version PR1ΔC predominantly localized to the endoplasmic reticulum (ER). The same localizations were found for stable Arabidopsis transformants with expression of PR1 and PR1ΔC driven by the native promoter. We conclude that the A. thaliana PR1 (AtPR1) undergoes an unconventional secretion pathway, starting from the C-terminus-dependent sorting from the ER, and utilizing further transportation via phosphatidyl-inositol-3-phosphate (PI(3)P) positive LE/MVB-like vesicles. The homology model of the PR1 structure shows that the cluster of positively charged amino acid residues (arginines 60, 67, 137, and lysine 135) could indeed interact with negatively charged phospholipids of cellular membranes. It remains to be resolved whether Golgi and LE/MVB localization reflects an alternative sorting or trafficking succession, and what the role of lipid interactions in it will be.
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Affiliation(s)
- Tamara Pečenková
- Laboratory of Cell Biology, Institute of Experimental Botany, Academy of Sciences of the Czech Republic, Rozvojova 263, 165 02 Prague 6, Czech Republic.
| | - Roman Pleskot
- Laboratory of Cell Biology, Institute of Experimental Botany, Academy of Sciences of the Czech Republic, Rozvojova 263, 165 02 Prague 6, Czech Republic.
| | - Viktor Žárský
- Laboratory of Cell Morphogenesis, Department of Experimental Plant Biology, Faculty of Science, Charles University in Prague, Vinicna 5, 128 44 Prague 2, Czech Republic.
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30
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Tavares LA, da Silva EML, da Silva-Januário ME, Januário YC, de Cavalho JV, Czernisz ÉS, Mardones GA, daSilva LLP. CD4 downregulation by the HIV-1 protein Nef reveals distinct roles for the γ1 and γ2 subunits of the AP-1 complex in protein trafficking. J Cell Sci 2016; 130:429-443. [PMID: 27909244 DOI: 10.1242/jcs.192104] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Accepted: 11/16/2016] [Indexed: 12/20/2022] Open
Abstract
The HIV accessory protein Nef is a major determinant of viral pathogenesis that facilitates viral particle release, prevents viral antigen presentation and increases infectivity of new virus particles. These functions of Nef involve its ability to remove specific host proteins from the surface of infected cells, including the CD4 receptor. Nef binds to the adaptor protein 2 (AP-2) and CD4 in clathrin-coated pits, forcing CD4 internalization and its subsequent targeting to lysosomes. Herein, we report that this lysosomal targeting requires a variant of AP-1 containing isoform 2 of γ-adaptin (AP1G2, hereafter γ2). Depletion of the γ2 or μ1A (AP1M1) subunits of AP-1, but not of γ1 (AP1G1), precludes Nef-mediated lysosomal degradation of CD4. In γ2-depleted cells, CD4 internalized by Nef accumulates in early endosomes and this alleviates CD4 removal from the cell surface. Depletion of γ2 also hinders EGFR-EGF-complex targeting to lysosomes, an effect that is not observed upon γ1 depletion. Taken together, our data provide evidence that the presence of γ1 or γ2 subunits delineates two distinct variants of AP-1 complexes, with different functions in protein sorting.
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Affiliation(s)
- Lucas A Tavares
- Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo 14049-900, Brazil
| | - Eulália M L da Silva
- Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo 14049-900, Brazil
| | - Mara E da Silva-Januário
- Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo 14049-900, Brazil
| | - Yunan C Januário
- Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo 14049-900, Brazil
| | - Julianne V de Cavalho
- Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo 14049-900, Brazil
| | - Érika S Czernisz
- Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo 14049-900, Brazil
| | - Gonzalo A Mardones
- Department of Physiology, School of Medicine, and Center for Interdisciplinary Studies of the Nervous System (CISNe), Universidad Austral de Chile, Valdivia 5110566, Chile
| | - Luis L P daSilva
- Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo 14049-900, Brazil
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31
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Schreij AMA, Fon EA, McPherson PS. Endocytic membrane trafficking and neurodegenerative disease. Cell Mol Life Sci 2016; 73:1529-45. [PMID: 26721251 PMCID: PMC11108351 DOI: 10.1007/s00018-015-2105-x] [Citation(s) in RCA: 105] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Revised: 10/26/2015] [Accepted: 11/26/2015] [Indexed: 12/11/2022]
Abstract
Neurodegenerative diseases are amongst the most devastating of human disorders. New technologies have led to a rapid increase in the identification of disease-related genes with an enhanced appreciation of the key roles played by genetics in the etiology of these disorders. Importantly, pinpointing the normal function of disease gene proteins leads to new understanding of the cellular machineries and pathways that are altered in the disease process. One such emerging pathway is membrane trafficking in the endosomal system. This key cellular process controls the localization and levels of a myriad of proteins and is thus critical for normal cell function. In this review we will focus on three neurodegenerative diseases; Parkinson disease, amyotrophic lateral sclerosis, and hereditary spastic paraplegias, for which a large number of newly discovered disease genes encode proteins that function in endosomal membrane trafficking. We will describe how alterations in these proteins affect endosomal function and speculate on the contributions of these disruptions to disease pathophysiology.
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Affiliation(s)
- Andrea M A Schreij
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, 3801 University Street, Montreal, QC, H3A 2B4, Canada
| | - Edward A Fon
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, 3801 University Street, Montreal, QC, H3A 2B4, Canada
| | - Peter S McPherson
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, 3801 University Street, Montreal, QC, H3A 2B4, Canada.
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Inoue J, Krueger EW, Chen J, Cao H, Ninomiya M, McNiven MA. HBV secretion is regulated through the activation of endocytic and autophagic compartments mediated by Rab7 stimulation. J Cell Sci 2015; 128:1696-706. [PMID: 25770103 DOI: 10.1242/jcs.158097] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2014] [Accepted: 03/06/2015] [Indexed: 01/05/2023] Open
Abstract
The cellular mechanisms by which hepatitis B virus (HBV) is assembled and exported are largely undefined. Recently, it has been suggested that these steps require the multivesicular body (MVB) and the autophagic machinery. However, the mechanisms by which HBV might regulate these compartments are unclear. In this study, we have found that by activating Rab7a, HBV alters its own secretion by inducing dramatic changes in the morphology of MVB and autophagic compartments. These changes are characterized by the formation of numerous tubules that are dependent upon the increase in Rab7 activity observed in the HBV-expressing HepG2.2.15 cells compared to HepG2 cells. Interestingly, transfection-based expression of the five individual viral proteins indicated that the precore protein, which is a precursor of HBeAg, was largely responsible for the increased Rab7 activity. Finally, small interfering RNA (siRNA)-mediated depletion of Rab7 significantly increased the secretion of virions, suggesting that reduced delivery of the virus to the lysosome facilitates viral secretion. These findings provide novel evidence indicating that HBV can regulate its own secretion through an activation of the endo-lysosomal and autophagic pathway mediated by Rab7 activation.
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Affiliation(s)
- Jun Inoue
- Department of Biochemistry and Molecular Biology, and Center for Basic Research in Digestive Diseases, Mayo Clinic, Rochester, MN 55905, USA Division of Gastroenterology, Tohoku University Graduate School of Medicine, Sendai, Miyagi 980-8574, Japan
| | - Eugene W Krueger
- Department of Biochemistry and Molecular Biology, and Center for Basic Research in Digestive Diseases, Mayo Clinic, Rochester, MN 55905, USA
| | - Jing Chen
- Department of Biochemistry and Molecular Biology, and Center for Basic Research in Digestive Diseases, Mayo Clinic, Rochester, MN 55905, USA
| | - Hong Cao
- Department of Biochemistry and Molecular Biology, and Center for Basic Research in Digestive Diseases, Mayo Clinic, Rochester, MN 55905, USA
| | - Masashi Ninomiya
- Department of Biochemistry and Molecular Biology, and Center for Basic Research in Digestive Diseases, Mayo Clinic, Rochester, MN 55905, USA Division of Gastroenterology, Tohoku University Graduate School of Medicine, Sendai, Miyagi 980-8574, Japan
| | - Mark A McNiven
- Department of Biochemistry and Molecular Biology, and Center for Basic Research in Digestive Diseases, Mayo Clinic, Rochester, MN 55905, USA
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Affiliation(s)
- François-Loïc Cosset
- CIRI - International Center for Infectiology Research, Team EVIR, Université de Lyon, Lyon, France; Inserm, U1111, Lyon, France; Ecole Normale Supérieure de Lyon, Lyon, France; Université Lyon 1, Centre International de Recherche en Infectiologie, Lyon, France; CNRS, UMR5308, Lyon, France; LabEx Ecofect, Université de Lyon, Lyon, France.
| | - Marlène Dreux
- CIRI - International Center for Infectiology Research, Team EVIR, Université de Lyon, Lyon, France; Inserm, U1111, Lyon, France; Ecole Normale Supérieure de Lyon, Lyon, France; Université Lyon 1, Centre International de Recherche en Infectiologie, Lyon, France; CNRS, UMR5308, Lyon, France; LabEx Ecofect, Université de Lyon, Lyon, France.
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Vild CJ, Xu Z. Vfa1 binds to the N-terminal microtubule-interacting and trafficking (MIT) domain of Vps4 and stimulates its ATPase activity. J Biol Chem 2014; 289:10378-10386. [PMID: 24567329 DOI: 10.1074/jbc.m113.532960] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The endosomal sorting complexes required for transport (ESCRT) are responsible for multivesicular body biogenesis, membrane abscission during cytokinesis, and retroviral budding. They function as transiently assembled molecular complexes on the membrane, and their disassembly requires the action of the AAA-ATPase Vps4. Vps4 is regulated by a multitude of ESCRT and ESCRT-related proteins. Binding of these proteins to Vps4 is often mediated via the microtubule-interacting and trafficking (MIT) domain of Vps4. Recently, a new Vps4-binding protein Vfa1 was identified in a yeast genetic screen, where overexpression of Vfa1 caused defects in vacuolar morphology. However, the function of Vfa1 and its role in vacuolar biology were largely unknown. Here, we provide the first detailed biochemical and biophysical study of Vps4-Vfa1 interaction. The MIT domain of Vps4 binds to the C-terminal 17 residues of Vfa1. This interaction is of high affinity and greatly stimulates the ATPase activity of Vps4. The crystal structure of the Vps4-Vfa1 complex shows that Vfa1 adopts a canonical MIT-interacting motif 2 structure that has been observed previously in other Vps4-ESCRT interactions. These findings suggest that Vfa1 is a novel positive regulator of Vps4 function.
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Affiliation(s)
- Cody J Vild
- Life Sciences Institute and Department of Biological Chemistry, Medical School, University of Michigan, Ann Arbor, Michigan 48109
| | - Zhaohui Xu
- Life Sciences Institute and Department of Biological Chemistry, Medical School, University of Michigan, Ann Arbor, Michigan 48109.
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Hoffmann J, Boehm C, Himmelsbach K, Donnerhak C, Roettger H, Weiss TS, Ploen D, Hildt E. Identification of α-taxilin as an essential factor for the life cycle of hepatitis B virus. J Hepatol 2013; 59:934-41. [PMID: 23816704 DOI: 10.1016/j.jhep.2013.06.020] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2013] [Revised: 06/04/2013] [Accepted: 06/20/2013] [Indexed: 01/11/2023]
Abstract
BACKGROUND & AIMS α-taxilin was identified as binding partner of syntaxins and is supposed to regulate vesicular trafficking. However, the physiological functions of α-taxilin and its potential relevance for the life cycle of hepatitis B virus (HBV) are still poorly understood. METHODS Transfected hepatoma cells, infected primary human hepatocytes, and liver tissue of HBV-infected patients were used to study the expression of α-taxilin. Subcellular localization and colocalization were analyzed by confocal laser scanning microscopy (CLSM). Protein-protein interactions were further investigated by co-immunoprecipitations. Silencing of α-taxilin expression was performed by lentiviral gene transfer. RESULTS HBV producing cells show a significant higher level of α-taxilin. HBV induces α-taxilin expression, by its regulatory proteins HBx and LHBs via c-Raf. This indicates that α-taxilin is essential for the release of HBV particles. CLSM and co-immunoprecipitations demonstrated that the PreS1PreS2 domain of LHBs interacts with α-taxilin. α-taxilin harbors a YXXL motif that represents a classic late domain. In accordance with this, it was found by co-immunoprecipitations that α-taxilin interacts with the ESCRT I component tsg101. CLSM revealed that a fraction of α-taxilin colocalizes with LHBs and tsg101. CONCLUSIONS α-taxilin plays an essential role for release of HBV-DNA containing particles. It might act as an adapter that binds, on the one hand, to LHBs and, on the other hand, to tsg101 and thereby helps recruit the ESCRT machinery to the viral envelope proteins.
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Affiliation(s)
- Jasmin Hoffmann
- Paul-Ehrlich-Institute, Division of Virology, D-63325 Langen, Germany
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Abstract
The pH of intracellular compartments is essential for the viability of cells. Despite its relevance, little is known about the pH of these compartments. To measure pH in vivo, we have first generated two pH sensors by combining the improved-solubility feature of solubility-modified green fluorescent protein (GFP) (smGFP) with the pH-sensing capability of the pHluorins and codon optimized for expression in Arabidopsis. PEpHluorin (plant-solubility-modified ecliptic pHluorin) gradually loses fluorescence as pH is lowered with fluorescence vanishing at pH 6.2 and PRpHluorin (plant-solubility-modified ratiomatric pHluorin), a dual-excitation sensor, allowing for precise measurements. Compartment-specific sensors were generated by further fusing specific sorting signals to PEpHluorin and PRpHluorin. Our results show that the pH of cytosol and nucleus is similar (pH 7.3 and 7.2), while peroxisomes, mitochondrial matrix, and plastidial stroma have alkaline pH. Compartments of the secretory pathway reveal a gradual acidification, spanning from pH 7.1 in the endoplasmic reticulum (ER) to pH 5.2 in the vacuole. Surprisingly, pH in the trans-Golgi network (TGN) and multivesicular body (MVB) is, with pH 6.3 and 6.2, quite similar. The inhibition of vacuolar-type H(+)-ATPase (V-ATPase) with concanamycin A (ConcA) caused drastic increase in pH in TGN and vacuole. Overall, the PEpHluorin and PRpHluorin are excellent pH sensors for visualization and quantification of pH in vivo, respectively.
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Affiliation(s)
- Jinbo Shen
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
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Silverman JS, Muratore KA, Bangs JD. Characterization of the late endosomal ESCRT machinery in Trypanosoma brucei. Traffic 2013; 14:1078-90. [PMID: 23905922 DOI: 10.1111/tra.12094] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Revised: 07/24/2013] [Accepted: 07/26/2013] [Indexed: 12/31/2022]
Abstract
The multivesicular body (MVB) is a specialized Rab7+ late endosome (LE) containing multiple intralumenal vesicles that function in targeting ubiquitinylated cell surface proteins to the lysosome for degradation. African trypanosomes lack a morphologically well-defined MVB, but contain orthologs of the ESCRT (Endosomal Sorting Complex Required for Transport) machinery that mediates MVB formation. We investigate the role of TbVps23, an early ESCRT component, and TbVps4, the terminal ESCRT ATPase, in lysosomal trafficking in bloodstream form trypanosomes. Both localize to the TbRab7+ LE and RNAi silencing of each rapidly blocks growth. TbVps4 silencing results in approximately threefold accumulation of TbVps23 at the LE, consistent with blocking terminal ESCRT disassembly. Trafficking of endocytic and biosynthetic cargo, but not default lysosomal reporters, is also negatively affected. Others reported that TbVps23 mediates ubiquitin-dependent lysosomal degradation of invariant surface glycoproteins (ISG65) (Leung et al., Traffic 2008;9:1698-1716). In contrast, we find that TbVps23 ablation does not affect ISG65 turnover, while TbVps4 silencing markedly enhances lysosomal degradation. We propose several models to accommodate these results, including that the ESCRT machinery actually retrieves ISG65 from the LE to earlier endocytic compartments, and in its absence ISG65 traffics more efficiently to the lysosome. Overall, these results confirm that the ESCRT machinery is essential in Trypanosoma brucei and plays important and novel role(s) in LE function in trypanosomes.
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Affiliation(s)
- Jason S Silverman
- Department of Microbiology and Immunology, School of Medicine and Biomedical Sciences, University at Buffalo (SUNY), 138 Farber Hall, 3435 Main Street, Buffalo, NY, 14214, USA; Current address: Monsanto Company, Mailstop LS2A, 800 N Lindbergh Blvd, Saint Louis, MO 63167, USA
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Badawi AH, Siahaan TJ. Suppression of MOG- and PLP-induced experimental autoimmune encephalomyelitis using a novel multivalent bifunctional peptide inhibitor. J Neuroimmunol 2013; 263:20-7. [PMID: 23911075 DOI: 10.1016/j.jneuroim.2013.07.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Revised: 07/03/2013] [Accepted: 07/10/2013] [Indexed: 01/08/2023]
Abstract
Previously, bifunctional peptide inhibitors (BPI) with a single antigenic peptide have been shown to suppress experimental autoimmune encephalomyelitis (EAE) in an antigen-specific manner. In this study, a multivalent BPI (MVBMOG/PLP) with two antigenic peptides derived from myelin oligodendrocyte glycoprotein (MOG38-50) and myelin proteolipid protein (PLP139-151) was evaluated in suppressing MOG38-50- and PLP139-151-induced EAE. MVBMOG/PLP significantly suppressed both models of EAE even when there was some evidence of epitope spreading in the MOG38-50-induced EAE model. In addition, MVBMOG/PLP was found to be more effective than PLP-BPI and MOG-BPI in suppressing MOG38-50-induced EAE. Thus, the development of MVB molecules with broader antigenic targets can lead to suppression of epitope spreading in EAE.
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Chapuy-Regaud S, Subra C, Requena M, de Medina P, Amara S, Delton-Vandenbroucke I, Payre B, Cazabat M, Carriere F, Izopet J, Poirot M, Record M. Progesterone and a phospholipase inhibitor increase the endosomal bis(monoacylglycero)phosphate content and block HIV viral particle intercellular transmission. Biochimie 2013; 95:1677-88. [PMID: 23774297 DOI: 10.1016/j.biochi.2013.05.019] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Accepted: 05/27/2013] [Indexed: 10/26/2022]
Abstract
Progesterone, the cationic amphiphile U18666A and a phospholipase inhibitor (Methyl Arachidonyl Fluoro Phosphonate, MAFP) inhibited by 70%-90% HIV production in viral reservoir cells, i.e. human THP-1 monocytes and monocyte-derived macrophages (MDM). These compounds triggered an inhibition of fluid phase endocytosis (macropinocytosis) and modified cellular lipid homeostasis since endosomes accumulated filipin-stained sterols and Bis(Monoacylglycero)Phosphate (BMP). BMP was quantified using a new cytometry procedure and was increased by 1.25 times with MAFP, 1.7 times with U18666A and 2.5 times with progesterone. MAFP but not progesterone or U18666A inhibited the hydrolysis of BMP by the Pancreatic Lipase Related Protein 2 (PLRP2) as shown by in-vitro experiments. The possible role of sterol transporters in steroid-mediated BMP increase is discussed. Electron microscopy showed the accumulation of viral particles either into large intracellular viral-containing compartments or outside the cells, indicating that endosomal accumulation of BMP could block intracellular biogenesis of viral particles while inhibition of macropinocytosis would prevent viral particle uptake. This is the first report linking BMP metabolism with a natural steroid such as progesterone or with involvement of a phospholipase A1 activity. BMP cellular content could be used as a biomarker for efficient anti-viral drugs.
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Affiliation(s)
- Sabine Chapuy-Regaud
- INSERM, U1043, Equipe Infection virales: persistance, réponse de l'hôte et physiopathologie, Toulouse F-31300, France
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Biasutto L, Chiechi A, Couch R, Liotta LA, Espina V. Retinal pigment epithelium (RPE) exosomes contain signaling phosphoproteins affected by oxidative stress. Exp Cell Res 2013; 319:2113-2123. [PMID: 23669273 DOI: 10.1016/j.yexcr.2013.05.005] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 05/03/2013] [Accepted: 05/04/2013] [Indexed: 12/23/2022]
Abstract
Age-related macular degeneration (AMD) is a leading cause of vision loss and blindness among the elderly population in the industrialized world. One of the typical features of this pathology is the gradual death of retinal pigment epithelial (RPE) cells, which are essential for maintaining photoreceptor functions and survival. The etiology is multifactorial, and oxidative stress is clearly one of the key factors involved in disease pathogenesis (Plafker, Adv. Exp. Med. Biol. 664 (2010) 447-56; Qin, Drug Dev. Res. 68 (2007) 213-225). Recent work has revealed the presence of phosphorylated signaling proteins in the vitreous humour of patients affected by AMD or other retinal diseases. While the location of these signaling proteins is typically the cell membrane or intracellular compartments, vitreous samples were proven to be cell-free (Davuluri et al., Arch. Ophthalmol. 127 (2009) 613-21). To gain a better understanding of how these proteins can be shed into the vitreous, we used reverse phase protein arrays (RPMA) to analyze the protein and phosphoprotein content of exosomes shed by cultured ARPE-19 cells under oxidative stress conditions. Seventy two proteins were shown to be released by ARPE-19 cells and compartmentalized within exosomes. Forty one of them were selectively detected in their post-translationally modified form (i.e., phosphorylated or cleaved) for the first time in exosomes. Sets of these proteins were linked together reflecting activation of pathway units within exosomes. A subset of (phospho)proteins were altered in exosomes secreted by ARPE-19 cells subjected to oxidative stress, compared to that secreted by control/non stressed cells. Stress-altered exosome proteins were found to be involved in pathways regulating apoptosis/survival (i.e, Bak, Smac/Diablo, PDK1 (S241), Akt (T308), Src (Y416), Elk1 (S383), ERK 1/2 (T202/Y204)) and cell metabolism (i.e., AMPKα1 (S485), acetyl-CoA carboxylase (S79), LDHA). Exosomes may thus represent the conduit through which membrane and intracellular signaling proteins are released into the vitreous. Changes in their (phospho)protein content upon stress conditions suggest their possible role in mediating cell-cell signaling during physio-pathological events; furthermore, exosomes may represent a potential source of biomarkers.
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Affiliation(s)
- Lucia Biasutto
- CNR Institute of Neuroscience, Viale G. Colombo 3, 35121 Padova, Italy; Department of Biomedical Sciences, University of Padova, Viale G. Colombo 3, 35121 Padova, Italy.
| | - Antonella Chiechi
- Center for Applied Proteomics and Molecular Medicine, George Mason University, 10900 University Blvd, Manassas, VA 20110, USA
| | - Robin Couch
- Department of Chemistry and Biochemistry, George Mason University, 10900 University Blvd, Manassas, VA 20110, USA
| | - Lance A Liotta
- Center for Applied Proteomics and Molecular Medicine, George Mason University, 10900 University Blvd, Manassas, VA 20110, USA
| | - Virginia Espina
- Center for Applied Proteomics and Molecular Medicine, George Mason University, 10900 University Blvd, Manassas, VA 20110, USA.
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Abstract
VPS9 domains can act as guanosine nucleotide exchange factors (GEFs) against small G proteins of the Rab5 family. Saccharomyces cerevisiae vps9Δ mutants have trafficking defects considerably less severe than multiple deletions of the three cognate Rab5 paralogs (Vps21, Ypt52, and Ypt53). Here, we show that Muk1, which also contains a VPS9 domain, acts as a second GEF against Vps21, Ypt52, and Ypt53. Muk1 is partially redundant with Vps9 in vivo, with vps9Δ muk1Δ double mutant cells displaying hypersensitivity to temperature and ionic stress, as well as profound impairments in endocytic and Golgi endosome trafficking, including defects in sorting through the multivesicular body. Cells lacking both Vps9 and Muk1 closely phenocopy double and triple knock-out strains lacking Rab5 paralogs. Microscopy and overexpression experiments demonstrate that Vps9 and Muk1 have distinct localization determinants. These experiments establish Muk1 as the second Rab5 GEF in budding yeast.
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Affiliation(s)
- Andrew L Paulsel
- Department of Biochemistry, University of Washington, Seattle, Washington 98195-7350, USA
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Abstract
The Epidermal Growth Factor Receptor (EGFR) is the prototypical receptor tyrosine kinase (RTK). These cell surface receptors are integral membrane proteins that bind ligands on their extracellular domain and relay that information to within the cell. The activated EGFR regulates diverse cell fates such as growth, proliferation, differentiation, migration, and apoptosis. These signaling properties are important for the appropriate development and maintenance of an organism. However, when inappropriately controlled, due to EGFR overexpression or hyperactivation, these signaling events are characteristic of many cancers. It remains unclear whether the uncontrolled EGFR activity leads to cell transformation or is a consequence of cell transformation. Regardless of the cause, increased EGFR activity serves both as a biomarker in the diagnosis of some cancers and is a molecular target for anti-cancer therapies. The promising results with current anti-EGFR therapies suggest that the receptor is a viable molecular target for a limited number of applications. However, to become an effective therapeutic target for other cancers that have elevated levels of EGFR activity, current approaches for inhibiting EGFR signaling will need to be refined. Here we describe the molecular mechanisms that regulate EGFR inactivation and discuss their potential as therapeutic targets for inhibiting EGFR signaling.
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Affiliation(s)
- Brian P Ceresa
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73190
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Jaillais Y, Gaude T. Sorting out the sorting functions of endosomes in Arabidopsis. Plant Signal Behav 2007; 2:556-8. [PMID: 19704558 PMCID: PMC2634368 DOI: 10.4161/psb.2.6.5108] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2007] [Accepted: 10/04/2007] [Indexed: 05/02/2023]
Abstract
In animals, sorting of membrane proteins following their internalization from the plasma membrane (PM) by endocytosis occurs through a series of different endosomal compartments. In plants, how and where these sorting events take place is still poorly understood and our current view of the endocytic pathway still largely relies on analogies made from the animal system. However, extensive differences seem to exist between animal and plant endosomal functions, as exemplified by the role of the trans-Golgi network (TGN) as an early endosomal compartment in plants or the functional diversification of conserved sorting complexes. By using the Arabidopsis root tip as a reference model, we and other have begun to shed light on the complexity of the plant endocytic pathways. Notably, we have recently characterized the functions of an endosomal compartment, the SNX1-endosomes, also referred to as the prevacuolar compartment (PVC) or multivesicular bodies (MVB), in the sorting of different cargo proteins, including two related auxin-efflux carriers, PIN1 and PIN2. We have shown that routing decisions take place at this endosomal level, such as the sorting of PIN2 toward the lytic vacuole for degradation or PIN1 toward the PM for recycling.
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Affiliation(s)
- Yvon Jaillais
- Reproduction et Développement des Plantes; Institut Fédératif de Recherche 128; Centre National de la Recherche Scientifique; Institut National de la Recherche Agronomique; Université Claude Bernard Lyon I; Ecole Normale Supérieure de Lyon; Lyon, France
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