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Echarri A, Pavón DM, Sánchez S, García-García M, Calvo E, Huerta-López C, Velázquez-Carreras D, Viaris de Lesegno C, Ariotti N, Lázaro-Carrillo A, Strippoli R, De Sancho D, Alegre-Cebollada J, Lamaze C, Parton RG, Del Pozo MA. An Abl-FBP17 mechanosensing system couples local plasma membrane curvature and stress fiber remodeling during mechanoadaptation. Nat Commun 2019; 10:5828. [PMID: 31862885 PMCID: PMC6925243 DOI: 10.1038/s41467-019-13782-2] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 11/22/2019] [Indexed: 12/19/2022] Open
Abstract
Cells remodel their structure in response to mechanical strain. However, how mechanical forces are translated into biochemical signals that coordinate the structural changes observed at the plasma membrane (PM) and the underlying cytoskeleton during mechanoadaptation is unclear. Here, we show that PM mechanoadaptation is controlled by a tension-sensing pathway composed of c-Abl tyrosine kinase and membrane curvature regulator FBP17. FBP17 is recruited to caveolae to induce the formation of caveolar rosettes. FBP17 deficient cells have reduced rosette density, lack PM tension buffering capacity under osmotic shock, and cannot adapt to mechanical strain. Mechanistically, tension is transduced to the FBP17 F-BAR domain by direct phosphorylation mediated by c-Abl, a mechanosensitive molecule. This modification inhibits FBP17 membrane bending activity and releases FBP17-controlled inhibition of mDia1-dependent stress fibers, favoring membrane adaptation to increased tension. This mechanoprotective mechanism adapts the cell to changes in mechanical tension by coupling PM and actin cytoskeleton remodeling. Mechanical forces are sensed by cells and can alter plasma membrane properties, but biochemical changes underlying this are not clear. Here the authors show tension is sensed by c-Abl and FBP17, which couples changes in mechanical tension to remodelling of the plasma membrane and actin cytoskeleton.
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Affiliation(s)
- Asier Echarri
- Mechanoadaptation and Caveolae Biology Laboratory, Cell and Developmental Biology Area, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Melchor Fernández Almagro, 3, 28029, Madrid, Spain.
| | - Dácil M Pavón
- Mechanoadaptation and Caveolae Biology Laboratory, Cell and Developmental Biology Area, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Melchor Fernández Almagro, 3, 28029, Madrid, Spain
| | - Sara Sánchez
- Mechanoadaptation and Caveolae Biology Laboratory, Cell and Developmental Biology Area, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Melchor Fernández Almagro, 3, 28029, Madrid, Spain
| | - María García-García
- Mechanoadaptation and Caveolae Biology Laboratory, Cell and Developmental Biology Area, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Melchor Fernández Almagro, 3, 28029, Madrid, Spain
| | - Enrique Calvo
- Proteomics Unit, Vascular Pathophysiology Area, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Melchor Fernández Almagro, 3, 28029, Madrid, Spain
| | - Carla Huerta-López
- Molecular Mechanics of the Cardiovascular System Laboratory, Cell and Developmental Biology Area, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Melchor Fernández Almagro, 3, 28029, Madrid, Spain
| | - Diana Velázquez-Carreras
- Molecular Mechanics of the Cardiovascular System Laboratory, Cell and Developmental Biology Area, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Melchor Fernández Almagro, 3, 28029, Madrid, Spain
| | - Christine Viaris de Lesegno
- Membrane Mechanics and Dynamics of Intracellular Signaling Laboratory, Institut Curie - Centre de Recherche, PSL Research University, CNRS UMR3666, INSERM U1143, 75248, Paris, France
| | - Nicholas Ariotti
- The Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Ana Lázaro-Carrillo
- Mechanoadaptation and Caveolae Biology Laboratory, Cell and Developmental Biology Area, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Melchor Fernández Almagro, 3, 28029, Madrid, Spain.,Departamento de Biología, Universidad Autónoma de Madrid, Cantoblanco, 28049, Madrid, Spain
| | | | - David De Sancho
- Departamento de Ciencia y Tecnología de Polímeros, Euskal Herriko Unibertsitatea, 20018, Donostia-San Sebastián, Spain.,Donostia International Physics Center, Manuel Lardizabal Ibilbidea, 4, 20018, Donostia-San Sebastián, Spain
| | - Jorge Alegre-Cebollada
- Molecular Mechanics of the Cardiovascular System Laboratory, Cell and Developmental Biology Area, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Melchor Fernández Almagro, 3, 28029, Madrid, Spain
| | - Christophe Lamaze
- Membrane Mechanics and Dynamics of Intracellular Signaling Laboratory, Institut Curie - Centre de Recherche, PSL Research University, CNRS UMR3666, INSERM U1143, 75248, Paris, France
| | - Robert G Parton
- The Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia.,The Centre for Microscopy and Microanalysis, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Miguel A Del Pozo
- Mechanoadaptation and Caveolae Biology Laboratory, Cell and Developmental Biology Area, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Melchor Fernández Almagro, 3, 28029, Madrid, Spain.
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Bayat N, McOrist N, Ariotti N, Lai M, Sia KC, Li Y, Grace JL, Quinn JF, Whittaker MR, Kavallaris M, Davis TP, Lock RB. Thiol-Reactive Star Polymers Functionalized with Short Ethoxy-Containing Moieties Exhibit Enhanced Uptake in Acute Lymphoblastic Leukemia Cells. Int J Nanomedicine 2019; 14:9795-9808. [PMID: 31853178 PMCID: PMC6914812 DOI: 10.2147/ijn.s220326] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 11/16/2019] [Indexed: 01/27/2023] Open
Abstract
Purpose Directing nanoparticles to cancer cells without using antibodies is of great interest. Subtle changes to the surface chemistry of nanoparticles can significantly affect their biological fate, including their propensity to associate with different cell populations. For instance, nanoparticles functionalized with thiol-reactive groups can potentially enhance association with cells that over-express cell-surface thiol groups. The potential of such an approach for enhancing drug delivery for childhood acute lymphoblastic leukemia (ALL) cells has not been investigated. Herein, we investigate the impact of thiol-reactive star polymers on the cellular association and the mechanisms of uptake of the nanoparticles. Methods We prepared fluorescently labeled star polymers functionalized with an mPEG brush corona and pyridyl disulfide to examine how reactivity to exofacial thiols impacts cellular association with ALL cells. We also studied how variations to the mPEG brush composition could potentially be used as a secondary method for controlling the extent of cell association. Specifically, we examined how the inclusion of shorter diethylene glycol brush moieties into the nanoparticle corona could be used to further influence cell association. Results Star polymers incorporating both thiol-reactive and diethylene glycol brush moieties exhibited the highest cellular association, followed by those functionalized solely with thiol reactive groups compared to control nanoparticles in T and B pediatric ALL patient-derived xenografts harvested from the spleens and bone marrow of immunodeficient mice. Transfection of cells with an early endosomal marker and imaging with correlative light and electron microscopy confirmed cellular uptake. Endocytosis inhibitors revealed dynamin-dependent clathrin-mediated endocytosis as the main uptake pathway for all the star polymers. Conclusion Thiol-reactive star polymers having an mPEG brush corona that includes a proportion of diethylene glycol brush moieties represent a potential strategy for improved leukemia cell delivery.
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Affiliation(s)
- Narges Bayat
- Leukemia Biology Program, Children's Cancer Institute, Lowy Cancer Research Centre, University of New South Wales, Sydney, NSW, Australia.,School of Women's and Children's Health, Faculty of Medicine, University of New South Wales, Sydney, Australia
| | - Nathan McOrist
- Leukemia Biology Program, Children's Cancer Institute, Lowy Cancer Research Centre, University of New South Wales, Sydney, NSW, Australia
| | - Nicholas Ariotti
- Electron Microscope Unit, Mark Wainwright Analytical Centre, Chemical Sciences Building, University of New South Wales, Sydney, NSW, Australia.,School of Medical Sciences, University of New South Wales, Sydney, NSW, Australia
| | - May Lai
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, and Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - Keith Cs Sia
- Leukemia Biology Program, Children's Cancer Institute, Lowy Cancer Research Centre, University of New South Wales, Sydney, NSW, Australia.,School of Women's and Children's Health, Faculty of Medicine, University of New South Wales, Sydney, Australia
| | - Yuhuan Li
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, and Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - James L Grace
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, and Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - John F Quinn
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, and Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - Michael R Whittaker
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, and Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - Maria Kavallaris
- School of Women's and Children's Health, Faculty of Medicine, University of New South Wales, Sydney, Australia.,Tumor Biology and Targeting Program, Children's Cancer Institute, Lowy Cancer Research Centre, University of New South Wales, Sydney, NSW, Australia.,Australian Centre for Nanomedicine, ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, University of New South Wales, Sydney, NSW, Australia
| | - Thomas P Davis
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, and Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia.,Department of Chemistry, University of Warwick, Coventry, UK.,Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Richard B Lock
- Leukemia Biology Program, Children's Cancer Institute, Lowy Cancer Research Centre, University of New South Wales, Sydney, NSW, Australia.,School of Women's and Children's Health, Faculty of Medicine, University of New South Wales, Sydney, Australia
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53
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Samaddar S, Mazur J, Boehm D, Thompson DH. Development And In Vitro Characterization Of Bladder Tumor Cell Targeted Lipid-Coated Polyplex For Dual Delivery Of Plasmids And Small Molecules. Int J Nanomedicine 2019; 14:9547-9561. [PMID: 31824150 PMCID: PMC6900316 DOI: 10.2147/ijn.s225172] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 10/22/2019] [Indexed: 01/25/2023] Open
Abstract
BACKGROUND Bladder cancer is the fourth most common cancer in men and eleventh most common in women. Combination therapy using a gene and chemotherapeutic drug is a potentially useful strategy for treating bladder cancer in cases where a synergistic benefit can be achieved successfully. This approach relies on developing drug combinations using carrier systems that can load both hydrophilic genes and hydrophobic drugs. Ideally, the formulation for carrier system should be free of traditional high shear techniques such as sonication and extrusion to reduce shear-induced nucleic acid strand breakage. Moreover, the system should be able to protect the nucleic acid from enzymatic attack and deliver it specifically to the tumor site. MATERIALS AND METHODS A dual payload carrier system that was formulated using a simple flow mixing technique to complex anionic plasmid (EGFP-NLS) using a cationic polymer (CD-PEI2.5kD) followed by coating of the polyplex using lipid membranes. The resulting lipid-coated polyplex (LCP) formulations are targeted to bladder cancer cells by employing a bacterial adhesive peptide sequence, RWFV, that targets the LCP to the tumor stroma for efficiently delivering reporter plasmid, EGFP-NLS and a model small molecule drug, pyrene, to the cancer cells. RESULTS Encapsulation efficiency of the peptide targeted carrier for the plasmid was 50% ± 0.4% and for pyrene it was 16% ± 0.4%. The ability of the targeted LCP to transfect murine bladder cancer cells was 4-fold higher than LCP bearing a scrambled peptide sequence. Fluorescence of cells due to pyrene delivery was highest after 4 hrs using targeted LCP. Finally, we loaded the peptide targeted LCP with anti-cancer agent, curcumin. The targeted formulation of curcumin resulted in only 45% viable cancer cells at a concentration of 5 µg/mL, whereas the empty and non-targeted formulations did not result any significant cell death. CONCLUSION These results demonstrate the specificity of the targeting peptide sequence in engaging tumor cells and the utility of the developed carrier platform to deliver a dual payload to bladder tumor cells.
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Affiliation(s)
- Shayak Samaddar
- Department of Chemistry, Purdue University, Bindley Bioscience Center, West Lafayette, Indiana47906, USA
| | - Joshua Mazur
- Department of Chemistry, Purdue University, Bindley Bioscience Center, West Lafayette, Indiana47906, USA
| | - Devin Boehm
- Department of Chemistry, Purdue University, Bindley Bioscience Center, West Lafayette, Indiana47906, USA
| | - David H Thompson
- Department of Chemistry, Purdue University, Bindley Bioscience Center, West Lafayette, Indiana47906, USA
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54
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Multiscale Imaging of Metastasis in Zebrafish. Trends Cancer 2019; 5:766-778. [DOI: 10.1016/j.trecan.2019.10.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 10/11/2019] [Accepted: 10/14/2019] [Indexed: 12/12/2022]
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55
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Bhattachan P, Rae J, Yu H, Jung W, Wei J, Parton RG, Dong B. Ascidian caveolin induces membrane curvature and protects tissue integrity and morphology during embryogenesis. FASEB J 2019; 34:1345-1361. [PMID: 31914618 DOI: 10.1096/fj.201901281r] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 10/30/2019] [Accepted: 11/14/2019] [Indexed: 01/20/2023]
Abstract
Cell morphology and tissue integrity are essential for embryogenesis. Caveolins are membrane proteins that induce the formation of surface pits called caveolae that serve as membrane reservoirs for cell and tissue protection during development. In vertebrates, caveolin 1 (Cav1) and caveolin 3 (Cav3) are required for caveola formation. However, the formation of caveola and the function of caveolins in invertebrates are largely unknown. In this study, three caveolins, Cav-a, Cav-b, and CavY, are identified in the genome of the invertebrate chordate Ciona spp. Based on phylogenetic analysis, Cav-a is found to be closely related to the vertebrate Cav1 and Cav3. In situ hybridization shows that Cav-a is expressed in Ciona embryonic notochord and muscle. Cell-free experiments, model cell culture systems, and in vivo experiments demonstrate that Ciona Cav-a has the ability to induce membrane curvature at the plasma membrane. Knockdown of Cav-a in Ciona embryos causes loss of invaginations in the plasma membrane and results in the failure of notochord elongation and lumenogenesis. Expression of a dominant-negative Cav-a point mutation causes cells to change shape and become displaced from the muscle and notochord to disrupt tissue integrity. Furthermore, we demonstrate that Cav-a vesicles show polarized trafficking and localize at the luminal membrane during notochord lumenogenesis. Taken together, these results show that the invertebrate chordate caveolin from Ciona plays crucial roles in tissue integrity and morphology by inducing membrane curvature and intracellular vesicle trafficking during embryogenesis.
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Affiliation(s)
- Punit Bhattachan
- Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.,Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, China
| | - James Rae
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD, Australia
| | - Haiyan Yu
- Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - WooRam Jung
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD, Australia
| | - Jiankai Wei
- Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.,Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, China
| | - Robert G Parton
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD, Australia.,Centre for Microscopy and Microanalysis, The University of Queensland, St. Lucia, QLD, Australia
| | - Bo Dong
- Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.,Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, China
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56
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Küey C, Larocque G, Clarke NI, Royle SJ. Unintended perturbation of protein function using GFP nanobodies in human cells. J Cell Sci 2019; 132:jcs234955. [PMID: 31601614 PMCID: PMC6857592 DOI: 10.1242/jcs.234955] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 10/03/2019] [Indexed: 12/28/2022] Open
Abstract
Tagging a protein of interest with GFP using genome editing is a popular approach to study protein function in cell and developmental biology. To avoid re-engineering cell lines or organisms in order to introduce additional tags, functionalized nanobodies that bind GFP can be used to extend the functionality of the GFP tag. We developed functionalized nanobodies, which we termed 'dongles', that could add, for example, an FKBP tag to a GFP-tagged protein of interest, enabling knocksideways experiments in GFP knock-in cell lines. The power of knocksideways is that it allows investigators to rapidly switch the protein from an active to an inactive state. We show that dongles allow for effective knocksideways of GFP-tagged proteins in genome-edited human cells. However, we discovered that nanobody binding to dynamin-2-GFP caused inhibition of dynamin function prior to knocksideways. The function of GFP-tagged tumor protein D54 (TPD54, also known as TPD52L2) in anterograde traffic was also perturbed by dongles. While these issues potentially limit the application of dongles, we discuss strategies for their deployment as cell biological tools.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Cansu Küey
- Centre for Mechanochemical Cell Biology, Warwick Medical School, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, UK
| | - Gabrielle Larocque
- Centre for Mechanochemical Cell Biology, Warwick Medical School, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, UK
| | - Nicholas I Clarke
- Centre for Mechanochemical Cell Biology, Warwick Medical School, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, UK
| | - Stephen J Royle
- Centre for Mechanochemical Cell Biology, Warwick Medical School, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, UK
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57
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Parton RG. Twenty years of traffic: A 2020 vision of cellular electron microscopy. Traffic 2019; 21:156-161. [DOI: 10.1111/tra.12684] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 08/12/2019] [Accepted: 08/13/2019] [Indexed: 02/01/2023]
Affiliation(s)
- Robert G. Parton
- Institute for Molecular Bioscience and Centre for Microscopy and Microanalysis The University of Queensland Brisbane Queensland Australia
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58
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Flotillins promote T cell receptor sorting through a fast Rab5-Rab11 endocytic recycling axis. Nat Commun 2019; 10:4392. [PMID: 31558725 PMCID: PMC6763463 DOI: 10.1038/s41467-019-12352-w] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 08/28/2019] [Indexed: 12/25/2022] Open
Abstract
The targeted endocytic recycling of the T cell receptor (TCR) to the immunological synapse is essential for T cell activation. Despite this, the mechanisms that underlie the sorting of internalised receptors into recycling endosomes remain poorly understood. To build a comprehensive picture of TCR recycling during T cell activation, we developed a suite of new imaging and quantification tools centred on photoactivation of fluorescent proteins. We show that the membrane-organising proteins, flotillin-1 and -2, are required for TCR to reach Rab5-positive endosomes immediately after endocytosis and for transfer from Rab5- to Rab11a-positive compartments. We further observe that after sorting into in Rab11a-positive vesicles, TCR recycles to the plasma membrane independent of flotillin expression. Our data suggest a mechanism whereby flotillins delineate a fast Rab5-Rab11a endocytic recycling axis and functionally contribute to regulate the spatial organisation of these endosomes. Internalized receptors are recycled back to the cell surface, but their precise mechanisms are unclear. Here, the authors show that the flotillin membrane proteins may regulate the transfer of internalized T cell receptors into Rab5 and Rab11-positive endosomes to support its rapid recycling.
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NPC1 regulates ER contacts with endocytic organelles to mediate cholesterol egress. Nat Commun 2019; 10:4276. [PMID: 31537798 PMCID: PMC6753064 DOI: 10.1038/s41467-019-12152-2] [Citation(s) in RCA: 175] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 08/19/2019] [Indexed: 12/19/2022] Open
Abstract
Transport of dietary cholesterol from endocytic organelles to the endoplasmic reticulum (ER) is essential for cholesterol homoeostasis, but the mechanism and regulation of this transport remains poorly defined. Membrane contact sites (MCS), microdomains of close membrane apposition, are gaining attention as important platforms for non-vesicular, inter-organellar communication. Here we investigate the impact of ER-endocytic organelle MCS on cholesterol transport. We report a role for Niemann-Pick type C protein 1 (NPC1) in tethering ER-endocytic organelle MCS where it interacts with the ER-localised sterol transport protein Gramd1b to regulate cholesterol egress. We show that artificially tethering MCS rescues the cholesterol accumulation that characterises NPC1-deficient cells, consistent with direct lysosome to ER cholesterol transport across MCS. Finally, we identify an expanded population of lysosome-mitochondria MCS in cells depleted of NPC1 or Gramd1b that is dependent on the late endosomal sterol-binding protein STARD3, likely underlying the mitochondrial cholesterol accumulation in NPC1-deficient cells. Though endocytosed dietary cholesterol is transferred to the endoplasmic reticulum (ER), how this is regulated is unclear. Here, the authors report a role for Niemann-Pick Type C Protein 1 (NPC1) in tethering endocytic organelles to the ER, which may contribute to interorganelle cholesterol transport.
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Frum T, Watts JL, Ralston A. TEAD4, YAP1 and WWTR1 prevent the premature onset of pluripotency prior to the 16-cell stage. Development 2019; 146:dev.179861. [PMID: 31444221 PMCID: PMC6765126 DOI: 10.1242/dev.179861] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Accepted: 08/09/2019] [Indexed: 12/15/2022]
Abstract
In mice, pluripotent cells are thought to derive from cells buried inside the embryo around the 16-cell stage. Sox2 is the only pluripotency gene known to be expressed specifically within inside cells at this stage. To understand how pluripotency is established, we therefore investigated the mechanisms regulating the initial activation of Sox2 expression. Surprisingly, Sox2 expression initiated normally in the absence of both Nanog and Oct4 (Pou5f1), highlighting differences between embryo and stem cell models of pluripotency. However, we observed precocious ectopic expression of Sox2 prior to the 16-cell stage in the absence of Yap1, Wwtr1 and Tead4. Interestingly, the repression of premature Sox2 expression was sensitive to LATS kinase activity, even though LATS proteins normally do not limit activity of TEAD4, YAP1 and WWTR1 during these early stages. Finally, we present evidence for direct transcriptional repression of Sox2 by YAP1, WWTR1 and TEAD4. Taken together, our observations reveal that, while embryos are initially competent to express Sox2 as early as the four-cell stage, transcriptional repression prevents the premature expression of Sox2, thereby restricting the pluripotency program to the stage when inside cells are first created. Highlighted Article: The pluripotency marker SOX2 is not initially regulated by OCT4 and NANOG, but by HIPPO pathway members during the first 2 days of mouse embryogenesis.
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Affiliation(s)
- Tristan Frum
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
| | - Jennifer L Watts
- Physiology Graduate Program, Michigan State University, East Lansing, MI 48824, USA.,Reproductive and Developmental Biology Training Program, Michigan State University, East Lansing, MI 48824, USA
| | - Amy Ralston
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA .,Reproductive and Developmental Biology Training Program, Michigan State University, East Lansing, MI 48824, USA
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Simpson JD, Smith SA, Thurecht KJ, Such G. Engineered Polymeric Materials for Biological Applications: Overcoming Challenges of the Bio-Nano Interface. Polymers (Basel) 2019; 11:E1441. [PMID: 31480780 PMCID: PMC6780590 DOI: 10.3390/polym11091441] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 08/28/2019] [Accepted: 08/29/2019] [Indexed: 12/11/2022] Open
Abstract
Nanomedicine has generated significant interest as an alternative to conventional cancertherapy due to the ability for nanoparticles to tune cargo release. However, while nanoparticletechnology has promised significant benefit, there are still limited examples of nanoparticles inclinical practice. The low translational success of nanoparticle research is due to the series ofbiological roadblocks that nanoparticles must migrate to be effective, including blood and plasmainteractions, clearance, extravasation, and tumor penetration, through to cellular targeting,internalization, and endosomal escape. It is important to consider these roadblocks holistically inorder to design more effective delivery systems. This perspective will discuss how nanoparticlescan be designed to migrate each of these biological challenges and thus improve nanoparticledelivery systems in the future. In this review, we have limited the literature discussed to studiesinvestigating the impact of polymer nanoparticle structure or composition on therapeutic deliveryand associated advancements. The focus of this review is to highlight the impact of nanoparticlecharacteristics on the interaction with different biological barriers. More specific studies/reviewshave been referenced where possible.
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Affiliation(s)
- Joshua D Simpson
- Centre for Advanced Imaging, Australian Institute for Bioengineering and Nanotechnology, ARC Centre of Excellence in Convergent Bio-Nano Science and Technology and ARC Training Centre for Innovation in Biomedical Imaging Technology, the University of Queensland, St Lucia QLD 4072, Australia;
| | - Samuel A Smith
- School of Chemistry, University of Melbourne, Parkville VIC 3010, Australia;
| | - Kristofer J. Thurecht
- Centre for Advanced Imaging, Australian Institute for Bioengineering and Nanotechnology, ARC Centre of Excellence in Convergent Bio-Nano Science and Technology and ARC Training Centre for Innovation in Biomedical Imaging Technology, the University of Queensland, St Lucia QLD 4072, Australia;
| | - Georgina Such
- School of Chemistry, University of Melbourne, Parkville VIC 3010, Australia;
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Long MJC, Liu X, Aye Y. Chemical Biology Gateways to Mapping Location, Association, and Pathway Responsivity. Front Chem 2019; 7:125. [PMID: 30949469 PMCID: PMC6437114 DOI: 10.3389/fchem.2019.00125] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2018] [Accepted: 02/18/2019] [Indexed: 12/14/2022] Open
Abstract
Here we discuss, how by applying chemical concepts to biological problems, methods have been developed to map spatiotemporal regulation of proteins and small-molecule modulation of proteome signaling responses. We outline why chemical-biology platforms are ideal for such purposes. We further discuss strengths and weaknesses of chemical-biology protocols, contrasting them against classical genetic and biochemical approaches. We make these evaluations based on three parameters: occupancy; functional information; and spatial restriction. We demonstrate how the specific choice of chemical reagent and experimental set-up unite to resolve biological problems. Potential improvements/extensions as well as specific controls that in our opinion are often overlooked or employed incorrectly are also considered. Finally, we discuss some of the latest emerging methods to illuminate how chemical-biology innovations provide a gateway toward information hitherto inaccessible by conventional genetic/biochemical means. Finally, we also caution against solely relying on chemical-biology strategies and urge the field to undertake orthogonal validations to ensure robustness of results.
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Affiliation(s)
| | - Xuyu Liu
- École Polytechnique Fédérale de Lausanne, Institute of Chemical Sciences and Engineering, Lausanne, Switzerland
| | - Yimon Aye
- École Polytechnique Fédérale de Lausanne, Institute of Chemical Sciences and Engineering, Lausanne, Switzerland
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63
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Wang H, Ma Q, Qi Y, Dong J, Du X, Rae J, Wang J, Wu WF, Brown AJ, Parton RG, Wu JW, Yang H. ORP2 Delivers Cholesterol to the Plasma Membrane in Exchange for Phosphatidylinositol 4, 5-Bisphosphate (PI(4,5)P2). Mol Cell 2019; 73:458-473.e7. [DOI: 10.1016/j.molcel.2018.11.014] [Citation(s) in RCA: 75] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2018] [Revised: 10/15/2018] [Accepted: 11/13/2018] [Indexed: 10/27/2022]
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64
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Membrane Curvature and Tension Control the Formation and Collapse of Caveolar Superstructures. Dev Cell 2019; 48:523-538.e4. [DOI: 10.1016/j.devcel.2018.12.005] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2018] [Revised: 07/24/2018] [Accepted: 12/14/2018] [Indexed: 01/13/2023]
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65
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Frum T, Murphy TM, Ralston A. HIPPO signaling resolves embryonic cell fate conflicts during establishment of pluripotency in vivo. eLife 2018; 7:42298. [PMID: 30526858 PMCID: PMC6289571 DOI: 10.7554/elife.42298] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 11/12/2018] [Indexed: 01/03/2023] Open
Abstract
During mammalian development, the challenge for the embryo is to override intrinsic cellular plasticity to drive cells to distinct fates. Here, we unveil novel roles for the HIPPO signaling pathway in controlling cell positioning and expression of Sox2, the first marker of pluripotency in the mouse early embryo. We show that maternal and zygotic YAP1 and WWTR1 repress Sox2 while promoting expression of the trophectoderm gene Cdx2 in parallel. Yet, Sox2 is more sensitive than Cdx2 to Yap1/Wwtr1 dosage, leading cells to a state of conflicted cell fate when YAP1/WWTR1 activity is moderate. Remarkably, HIPPO signaling activity resolves conflicted cell fate by repositioning cells to the interior of the embryo, independent of its role in regulating Sox2 expression. Rather, HIPPO antagonizes apical localization of Par complex components PARD6B and aPKC. Thus, negative feedback between HIPPO and Par complex components ensure robust lineage segregation. As an embryo develops, its cells divide, grow and migrate in specific patterns to build an organized collection of cells that go on to form our tissues and organs. One of the first steps – well before the embryo has implanted into the womb – is to allocate cells to make part of the placenta. Once this process is complete, the remaining cells continue building the organism. These cells are pluripotent, meaning they can develop into any part of the body. Scientists think that the embryo manages to sort ‘placenta cells’ from pluripotent ones with the help of certain proteins, which the mother has packaged into her eggs. To investigate this further, Frum et al. used genetic tools to track a specific gene called Sox2 that identifies pluripotent cells as soon as they are formed in mouse embryos. The experiments revealed that the mother places two closely related proteins known as YAP1 and WWTR1 within each egg, which help to make placenta cells different from pluripotent cells. Moreover, both proteins enable the embryo to segregate these two cell types to two different locations: placenta cells are moved to the outer layer of the embryo, while pluripotent cells are moved to the inside. Current technologies allow researchers to create pluripotent cells in the laboratory. But these approaches often result in error, failing to replicate the embryo’s natural ability. By studying how embryos form and arrange pluripotent cells, scientists hope to advance stem cell technology (which emerge from pluripotent cells). This may help to find new ways to heal damaged tissues and organs, or to treat or even prevent many diseases.
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Affiliation(s)
- Tristan Frum
- Department of Biochemistry and Molecular Biology, Michigan State University, Michigan, United States
| | - Tayler M Murphy
- Genetics Graduate Program, Michigan State University, Michigan, United States.,Reproductive and Developmental Biology Training Program, Michigan State University, Michigan, United States
| | - Amy Ralston
- Department of Biochemistry and Molecular Biology, Michigan State University, Michigan, United States.,Genetics Graduate Program, Michigan State University, Michigan, United States.,Reproductive and Developmental Biology Training Program, Michigan State University, Michigan, United States
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66
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Hall TE, Rae J, Ariotti N, G Parton R. Electron Microscopic Detection of Proteins and Protein Complexes in Mammalian Cells Using APEX-tagged, Conditionally Stable Nanobodies. Bio Protoc 2018; 8:e3088. [PMID: 34532541 DOI: 10.21769/bioprotoc.3088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 11/06/2018] [Accepted: 11/20/2018] [Indexed: 11/02/2022] Open
Abstract
The recent development of 3D electron microscopic techniques for cells and tissues has necessitated the development of new methods for the detection of proteins and protein-complexes in situ. The development of new genetic tags, such as the ascorbate peroxidase, APEX, for electron microscopic detection of tagged proteins has expanded the available toolbox and ushered in a new era in biological electron microscopy. Here, we describe methods for combining conditionally-stable nanobodies to fluorescent protein tags with APEX-based detection. These methods are compatible with detection of low levels of expression of fluorescently-tagged proteins and with detection of protein complexes using split GFP-based complementation methods. We describe a simple protocol for applying these methods to the electron microscopic detection of proteins and protein complexes in cultured cells.
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Affiliation(s)
- Thomas E Hall
- The University of Queensland, Institute for Molecular Bioscience, Queensland 4072, Australia
| | - James Rae
- The University of Queensland, Institute for Molecular Bioscience, Queensland 4072, Australia
| | - Nicholas Ariotti
- The University of Queensland, Institute for Molecular Bioscience, Queensland 4072, Australia
| | - Robert G Parton
- The University of Queensland, Institute for Molecular Bioscience, Queensland 4072, Australia.,The University of Queensland, Centre for Microscopy and Microanalysis, Brisbane, Queensland 4072, Australia
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67
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Abstract
The plasma membrane of eukaryotic cells is not a simple sheet of lipids and proteins but is differentiated into subdomains with crucial functions. Caveolae, small pits in the plasma membrane, are the most abundant surface subdomains of many mammalian cells. The cellular functions of caveolae have long remained obscure, but a new molecular understanding of caveola formation has led to insights into their workings. Caveolae are formed by the coordinated action of a number of lipid-interacting proteins to produce a microdomain with a specific structure and lipid composition. Caveolae can bud from the plasma membrane to form an endocytic vesicle or can flatten into the membrane to help cells withstand mechanical stress. The role of caveolae as mechanoprotective and signal transduction elements is reviewed in the context of disease conditions associated with caveola dysfunction.
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Affiliation(s)
- Robert G. Parton
- Institute for Molecular Bioscience and Centre for Microscopy and Microanalysis, University of Queensland, Brisbane, Queensland 4060, Australia
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68
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Correlated Light-Serial Scanning Electron Microscopy (CoLSSEM) for ultrastructural visualization of single neurons in vivo. Sci Rep 2018; 8:14491. [PMID: 30262876 PMCID: PMC6160427 DOI: 10.1038/s41598-018-32820-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Accepted: 09/14/2018] [Indexed: 11/09/2022] Open
Abstract
A challenging aspect of neuroscience revolves around mapping the synaptic connections within neural circuits (connectomics) over scales spanning several orders of magnitude (nanometers to meters). Despite significant improvements in serial section electron microscopy (SSEM) technologies, several major roadblocks have impaired its general applicability to mammalian neural circuits. In the present study, we introduce a new approach that circumvents some of these roadblocks by adapting a genetically-encoded ascorbate peroxidase (APEX2) as a fusion protein to a membrane-targeted fluorescent reporter (CAAX-Venus), and introduce it in single pyramidal neurons in vivo using extremely sparse in utero cortical electroporation. This approach allows us to perform Correlated Light-SSEM (CoLSSEM), a variant of Correlated Light-EM (CLEM), on individual neurons, reconstructing their dendritic and axonal arborization in a targeted way via combination of high-resolution confocal microscopy, and subsequent imaging of its ultrastructural features and synaptic connections with ATUM-SEM (automated tape-collecting ultramicrotome - scanning electron microscopy) technology. Our method significantly will improve the feasibility of large-scale reconstructions of neurons within a circuit, and permits the description of some ultrastructural features of identified neurons with their functional and/or structural connectivity, one of the main goal of connectomics.
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69
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Sugo M, Kimura H, Arasaki K, Amemiya T, Hirota N, Dohmae N, Imai Y, Inoshita T, Shiba-Fukushima K, Hattori N, Cheng J, Fujimoto T, Wakana Y, Inoue H, Tagaya M. Syntaxin 17 regulates the localization and function of PGAM5 in mitochondrial division and mitophagy. EMBO J 2018; 37:embj.201798899. [PMID: 30237312 DOI: 10.15252/embj.201798899] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2017] [Revised: 08/03/2018] [Accepted: 08/13/2018] [Indexed: 12/26/2022] Open
Abstract
PGAM5, a mitochondrial protein phosphatase that is genetically and biochemically linked to PINK1, facilitates mitochondrial division by dephosphorylating the mitochondrial fission factor Drp1. At the onset of mitophagy, PGAM5 is cleaved by PARL, a rhomboid protease that degrades PINK1 in healthy cells, and the cleaved form facilitates the engulfment of damaged mitochondria by autophagosomes by dephosphorylating the mitophagy receptor FUNDC1. Here, we show that the function and localization of PGAM5 are regulated by syntaxin 17 (Stx17), a mitochondria-associated membrane/mitochondria protein implicated in mitochondrial dynamics in fed cells and autophagy in starved cells. In healthy cells, loss of Stx17 causes PGAM5 aggregation within mitochondria and thereby failure of the dephosphorylation of Drp1, leading to mitochondrial elongation. In Parkin-mediated mitophagy, Stx17 is prerequisite for PGAM5 to interact with FUNDC1. Our results reveal that the Stx17-PGAM5 axis plays pivotal roles in mitochondrial division and PINK1/Parkin-mediated mitophagy.
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Affiliation(s)
- Masashi Sugo
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, Japan
| | - Hana Kimura
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, Japan
| | - Kohei Arasaki
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, Japan
| | - Toshiki Amemiya
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, Japan
| | - Naohiko Hirota
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, Japan
| | - Naoshi Dohmae
- Biomolecular Characterization Unit, RIKEN Center for Sustainable Resource Science, Wako, Japan
| | - Yuzuru Imai
- Department of Research for Parkinson's Disease, Juntendo University Graduate School of Medicine, Tokyo, Japan.,Department of Neurology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Tsuyoshi Inoshita
- Department of Treatment and Research in Multiple Sclerosis and Neuro-intractable Disease, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Kahori Shiba-Fukushima
- Department of Treatment and Research in Multiple Sclerosis and Neuro-intractable Disease, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Nobutaka Hattori
- Department of Research for Parkinson's Disease, Juntendo University Graduate School of Medicine, Tokyo, Japan.,Department of Neurology, Juntendo University Graduate School of Medicine, Tokyo, Japan.,Department of Treatment and Research in Multiple Sclerosis and Neuro-intractable Disease, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Jinglei Cheng
- Department of Anatomy and Molecular Cell Biology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Toyoshi Fujimoto
- Department of Anatomy and Molecular Cell Biology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Yuichi Wakana
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, Japan
| | - Hiroki Inoue
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, Japan
| | - Mitsuo Tagaya
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, Japan
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70
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Tillu VA, Lim YW, Kovtun O, Mureev S, Ferguson C, Bastiani M, McMahon KA, Lo HP, Hall TE, Alexandrov K, Collins BM, Parton RG. A variable undecad repeat domain in cavin1 regulates caveola formation and stability. EMBO Rep 2018; 19:e45775. [PMID: 30021837 PMCID: PMC6123655 DOI: 10.15252/embr.201845775] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 06/05/2018] [Accepted: 06/14/2018] [Indexed: 11/09/2022] Open
Abstract
Caveolae are plasma membrane invaginations involved in transport, signalling and mechanical membrane sensing in metazoans. Their formation depends upon multiple interactions between membrane-embedded caveolins, lipids and cytosolic cavin proteins. Of the four cavin family members, only cavin1 is strictly required for caveola formation. Here, we demonstrate that an eleven residue (undecad) repeat sequence (UC1) exclusive to cavin1 is essential for caveolar localization and promotes membrane remodelling through binding to phosphatidylserine. In the notochord of mechanically stimulated zebrafish embryos, the UC1 domain is required for caveolar stability and resistance to membrane stress. The number of undecad repeats in the cavin1 UC1 domain varies throughout evolution, and we find that an increased number also correlates with increased caveolar stability. Lastly, we show that the cavin1 UC1 domain induces dramatic remodelling of the plasma membrane when grafted into cavin2 suggesting an important role in membrane sculpting. Overall, our work defines a novel conserved cavin1 modular domain that controls caveolar assembly and stability.
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Affiliation(s)
- Vikas A Tillu
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Qld, Australia
| | - Ye-Wheen Lim
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Qld, Australia
| | - Oleksiy Kovtun
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Qld, Australia
| | - Sergey Mureev
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Qld, Australia
| | - Charles Ferguson
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Qld, Australia
| | - Michele Bastiani
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Qld, Australia
| | - Kerrie-Ann McMahon
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Qld, Australia
| | - Harriet P Lo
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Qld, Australia
| | - Thomas E Hall
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Qld, Australia
| | - Kirill Alexandrov
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Qld, Australia
| | - Brett M Collins
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Qld, Australia
| | - Robert G Parton
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Qld, Australia
- Centre for Microscopy and Microanalysis, The University of Queensland, St. Lucia, Qld, Australia
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71
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Sathe M, Muthukrishnan G, Rae J, Disanza A, Thattai M, Scita G, Parton RG, Mayor S. Small GTPases and BAR domain proteins regulate branched actin polymerisation for clathrin and dynamin-independent endocytosis. Nat Commun 2018; 9:1835. [PMID: 29743604 PMCID: PMC5943408 DOI: 10.1038/s41467-018-03955-w] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Accepted: 03/22/2018] [Indexed: 01/10/2023] Open
Abstract
Using real-time TIRF microscopy imaging, we identify sites of clathrin and dynamin-independent CLIC/GEEC (CG) endocytic vesicle formation. This allows spatio-temporal localisation of known molecules affecting CG endocytosis; GBF1 (a GEF for ARF1), ARF1 and CDC42 which appear sequentially over 60 s, preceding scission. In an RNAi screen for BAR domain proteins affecting CG endocytosis, IRSp53 and PICK1, known interactors of CDC42 and ARF1, respectively, were selected. Removal of IRSp53, a negative curvature sensing protein, abolishes CG endocytosis. Furthermore, the identification of ARP2/3 complex at CG endocytic sites, maintained in an inactive state reveals a function for PICK1, an ARP2/3 inhibitor. The spatio-temporal sequence of the arrival and disappearance of the molecules suggest a mechanism for a clathrin and dynamin-independent endocytic process. Coincident with the loss of PICK1 by GBF1-activated ARF1, CDC42 recruitment leads to the activation of IRSp53 and the ARP2/3 complex, resulting in a burst of F-actin polymerisation potentially powering scission. Several endocytic pathways operate simultaneously at the cell surface, including the clathrin and dynamin-independent CLIC/GEEC (CG) pathway. Here the authors show that small GTPases and BAR domain proteins regulate branched actin to make clathrin and dynamin-independent endocytic vesicles.
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Affiliation(s)
- Mugdha Sathe
- National Centre for Biological Science (TIFR), Bellary Road, Bangalore, 560065, India
| | - Gayatri Muthukrishnan
- National Centre for Biological Science (TIFR), Bellary Road, Bangalore, 560065, India
| | - James Rae
- Institute for Molecular Bioscience, University of Queensland, Brisbane, QLD, 4072, Australia.,Centre for Microscopy and Microanalysis, University of Queensland, Brisbane, QLD, 4072, Australia
| | - Andrea Disanza
- IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Milan, 20139, Italy.,Department of Oncology and Hemato-Oncology, University of Milan, Milan, 20122, Italy
| | - Mukund Thattai
- National Centre for Biological Science (TIFR), Bellary Road, Bangalore, 560065, India.,Simons Centre for the Study of Living Machines, National Centre for Biological Sciences (TIFR), Bellary Road, Bangalore, 560065, India
| | - Giorgio Scita
- IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Milan, 20139, Italy.,Department of Oncology and Hemato-Oncology, University of Milan, Milan, 20122, Italy
| | - Robert G Parton
- Institute for Molecular Bioscience, University of Queensland, Brisbane, QLD, 4072, Australia.,Centre for Microscopy and Microanalysis, University of Queensland, Brisbane, QLD, 4072, Australia
| | - Satyajit Mayor
- National Centre for Biological Science (TIFR), Bellary Road, Bangalore, 560065, India. .,Institute for Stem Cell Biology and Regenerative Medicine, Bellary Road, Bangalore, 560065, India.
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72
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Ariotti N, Rae J, Giles N, Martel N, Sierecki E, Gambin Y, Hall TE, Parton RG. Ultrastructural localisation of protein interactions using conditionally stable nanobodies. PLoS Biol 2018; 16:e2005473. [PMID: 29621251 PMCID: PMC5903671 DOI: 10.1371/journal.pbio.2005473] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 04/17/2018] [Accepted: 03/20/2018] [Indexed: 01/21/2023] Open
Abstract
We describe the development and application of a suite of modular tools for high-resolution detection of proteins and intracellular protein complexes by electron microscopy (EM). Conditionally stable GFP- and mCherry-binding nanobodies (termed csGBP and csChBP, respectively) are characterized using a cell-free expression and analysis system and subsequently fused to an ascorbate peroxidase (APEX) enzyme. Expression of these cassettes alongside fluorescently labelled proteins results in recruitment and stabilisation of APEX, whereas unbound APEX nanobodies are efficiently degraded by the proteasome. This greatly simplifies correlative analyses, enables detection of less-abundant proteins, and eliminates the need to balance expression levels between fluorescently labelled and APEX nanobody proteins. Furthermore, we demonstrate the application of this system to bimolecular complementation ('EM split-fluorescent protein'), for localisation of protein-protein interactions at the ultrastructural level.
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Affiliation(s)
- Nicholas Ariotti
- The University of Queensland, Institute for Molecular Bioscience, Queensland, Australia
| | - James Rae
- The University of Queensland, Institute for Molecular Bioscience, Queensland, Australia
| | - Nichole Giles
- EMBL Australia Node in Single Molecule Sciences, School of Medical Science, The University of New South Wales, Sydney, New South Wales, Australia
| | - Nick Martel
- The University of Queensland, Institute for Molecular Bioscience, Queensland, Australia
| | - Emma Sierecki
- EMBL Australia Node in Single Molecule Sciences, School of Medical Science, The University of New South Wales, Sydney, New South Wales, Australia
| | - Yann Gambin
- EMBL Australia Node in Single Molecule Sciences, School of Medical Science, The University of New South Wales, Sydney, New South Wales, Australia
| | - Thomas E. Hall
- The University of Queensland, Institute for Molecular Bioscience, Queensland, Australia
| | - Robert G. Parton
- The University of Queensland, Institute for Molecular Bioscience, Queensland, Australia
- The University of Queensland, Centre for Microscopy and Microanalysis, Brisbane, Queensland, Australia
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73
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Barklis E, Staubus AO, Mack A, Harper L, Barklis RL, Alfadhli A. Lipid biosensor interactions with wild type and matrix deletion HIV-1 Gag proteins. Virology 2018; 518:264-271. [PMID: 29549788 DOI: 10.1016/j.virol.2018.03.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 03/03/2018] [Accepted: 03/06/2018] [Indexed: 11/19/2022]
Abstract
The matrix (MA) domain of the HIV-1 precursor Gag protein (PrGag) has been shown interact with the HIV-1 envelope (Env) protein, and to direct PrGag proteins to plasma membrane (PM) assembly sites by virtue of its affinity to phosphatidylinositol-4,5-bisphosphate (PI[4,5]P2). Unexpectedly, HIV-1 viruses with large MA deletions (ΔMA) have been shown to be conditionally infectious as long as they are matched with Env truncation mutant proteins or alternative viral glycoproteins. To characterize the interactions of wild type (WT) and ΔMA Gag proteins with PI(4,5)P2 and other acidic phospholipids, we have employed a set of lipid biosensors as probes. Our investigations showed marked differences in WT and ΔMA Gag colocalization with biosensors, effects on biosensor release, and association of biosensors with virus-like particles. These results demonstrate an alternative approach to the analysis of viral protein-lipid associations, and provide new data as to the lipid compositions of HIV-1 assembly sites.
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Affiliation(s)
- Eric Barklis
- Department of Molecular Microbiology and Immunology, Oregon Health and Sciences University, 3181 SW Sam Jackson Park Road, Portland, OR 97035, United States.
| | - August O Staubus
- Department of Molecular Microbiology and Immunology, Oregon Health and Sciences University, 3181 SW Sam Jackson Park Road, Portland, OR 97035, United States
| | - Andrew Mack
- Department of Molecular Microbiology and Immunology, Oregon Health and Sciences University, 3181 SW Sam Jackson Park Road, Portland, OR 97035, United States
| | - Logan Harper
- Department of Molecular Microbiology and Immunology, Oregon Health and Sciences University, 3181 SW Sam Jackson Park Road, Portland, OR 97035, United States
| | - Robin Lid Barklis
- Department of Molecular Microbiology and Immunology, Oregon Health and Sciences University, 3181 SW Sam Jackson Park Road, Portland, OR 97035, United States
| | - Ayna Alfadhli
- Department of Molecular Microbiology and Immunology, Oregon Health and Sciences University, 3181 SW Sam Jackson Park Road, Portland, OR 97035, United States
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74
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Reporter-nanobody fusions (RANbodies) as versatile, small, sensitive immunohistochemical reagents. Proc Natl Acad Sci U S A 2018; 115:2126-2131. [PMID: 29440485 DOI: 10.1073/pnas.1722491115] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Sensitive and specific antibodies are essential for detecting molecules in cells and tissues. However, currently used polyclonal and monoclonal antibodies are often less specific than desired, difficult to produce, and available in limited quantities. A promising recent approach to circumvent these limitations is to employ chemically defined antigen-combining domains called "nanobodies," derived from single-chain camelid antibodies. Here, we used nanobodies to prepare sensitive unimolecular detection reagents by genetically fusing cDNAs encoding nanobodies to enzymatic or antigenic reporters. We call these fusions between a reporter and a nanobody "RANbodies." They can be used to localize epitopes and to amplify signals from fluorescent proteins. They can be generated and purified simply and in unlimited amounts and can be preserved safely and inexpensively in the form of DNA or digital sequence.
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75
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Xu D, Li Y, Wu L, Li Y, Zhao D, Yu J, Huang T, Ferguson C, Parton RG, Yang H, Li P. Rab18 promotes lipid droplet (LD) growth by tethering the ER to LDs through SNARE and NRZ interactions. J Cell Biol 2018; 217:975-995. [PMID: 29367353 PMCID: PMC5839781 DOI: 10.1083/jcb.201704184] [Citation(s) in RCA: 154] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2017] [Revised: 10/12/2017] [Accepted: 12/22/2017] [Indexed: 12/16/2022] Open
Abstract
Lipid incorporation from endoplasmic reticulum (ER) to lipid droplet (LD) is important in controlling LD growth and intracellular lipid homeostasis. However, the molecular link mediating ER and LD cross talk remains elusive. Here, we identified Rab18 as an important Rab guanosine triphosphatase in controlling LD growth and maturation. Rab18 deficiency resulted in a drastically reduced number of mature LDs and decreased lipid storage, and was accompanied by increased ER stress. Rab3GAP1/2, the GEF of Rab18, promoted LD growth by activating and targeting Rab18 to LDs. LD-associated Rab18 bound specifically to the ER-associated NAG-RINT1-ZW10 (NRZ) tethering complex and their associated SNAREs (Syntaxin18, Use1, BNIP1), resulting in the recruitment of ER to LD and the formation of direct ER-LD contact. Cells with defects in the NRZ/SNARE complex function showed reduced LD growth and lipid storage. Overall, our data reveal that the Rab18-NRZ-SNARE complex is critical protein machinery for tethering ER-LD and establishing ER-LD contact to promote LD growth.
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Affiliation(s)
- Dijin Xu
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Yuqi Li
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Lizhen Wu
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Ying Li
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Dongyu Zhao
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Jinhai Yu
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Tuozhi Huang
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Charles Ferguson
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Australia
| | - Robert G Parton
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Australia.,Centre for Microscopy and Microanalysis, University of Queensland, Brisbane, Australia
| | - Hongyuan Yang
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, Australia
| | - Peng Li
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
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76
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Abstract
Probes are essential to visualize proteins in their cellular environment, both using light microscopy as well as electron microscopy (EM). Correlated light microscopy and electron microscopy (CLEM) requires probes that can be imaged simultaneously by both optical and electron-dense signals. Existing combinatorial probes often have impaired efficiency, need ectopic expression as a fusion protein, or do not target endogenous proteins. Here, we present FLIPPER-bodies to label endogenous proteins for CLEM. Fluorescent Indicator and Peroxidase for Precipitation with EM Resolution (FLIPPER), the combination of a fluorescent protein and a peroxidase, is fused to a nanobody against a target of interest. The modular nature of these probes allows an easy exchange of components to change its target or color. A general FLIPPER-body targeting GFP highlights histone2B-GFP both in fluorescence and in EM. Similarly, endogenous EGF receptors and HER2 are visualized at nm-scale resolution in ultrastructural context. The small and flexible FLIPPER-body outperforms IgG-based immuno-labeling, likely by better reaching the epitopes. Given the modular domains and possibilities of nanobody generation for other targets, FLIPPER-bodies have high potential to become a universal tool to identify proteins in immuno-CLEM with increased sensitivity compared to current approaches.
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77
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Clarke NI, Royle SJ. Correlating light microscopy with serial block face scanning electron microscopy to study mitotic spindle architecture. Methods Cell Biol 2018; 145:29-43. [PMID: 29957210 DOI: 10.1016/bs.mcb.2018.03.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The mitotic spindle is a complex structure that coordinates the accurate segregation of chromosomes during cell division. To understand how the mitotic spindle operates at the molecular level, high resolution imaging is needed. Serial block face-scanning electron microscopy (SBF-SEM) is a technique that can be used to visualize the ultrastructure of entire cells, including components of the mitotic spindle such as microtubules, kinetochores, centrosomes, and chromosomes. Although transmission electron microscopy (TEM) has higher resolution, the reconstruction of large volumes using TEM and tomography is labor intensive, whereas SBF-SEM takes only days to process, image, and segment samples. SBF-SEM fills the resolution gap between light microscopy (LM) and TEM. When combined with LM, SBF-SEM provides a platform where dynamic cellular events can be selected and imaged at high resolution. Here we outline methods to use correlation and SBF-SEM to study mitotic spindle architecture in 3D with high resolution.
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Affiliation(s)
- Nicholas I Clarke
- Centre for Mechanochemical Cell Biology, Warwick Medical School, Coventry, United Kingdom
| | - Stephen J Royle
- Centre for Mechanochemical Cell Biology, Warwick Medical School, Coventry, United Kingdom.
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78
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Snyers L, Erhart R, Laffer S, Pusch O, Weipoltshammer K, Schöfer C. LEM4/ANKLE-2 deficiency impairs post-mitotic re-localization of BAF, LAP2α and LaminA to the nucleus, causes nuclear envelope instability in telophase and leads to hyperploidy in HeLa cells. Eur J Cell Biol 2017; 97:63-74. [PMID: 29254732 DOI: 10.1016/j.ejcb.2017.12.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 12/05/2017] [Accepted: 12/06/2017] [Indexed: 01/01/2023] Open
Abstract
The human LEM-domain protein family is involved in fundamental aspects of nuclear biology. The LEM-domain interacts with the barrier-to-autointegration factor (BAF), which itself binds DNA. LEM-domain proteins LAP2, emerin and MAN1 are proteins of the inner nuclear membrane; they have important functions: maintaining the integrity of the nuclear lamina and regulating gene expression at the nuclear periphery. LEM4/ANKLE-2 has been proposed to participate in nuclear envelope reassembly after mitosis and to mediate dephosphorylation of BAF through binding to phosphatase PP2A. Here, we used CRISPR/Cas9 to create several cell lines deficient in LEM4/ANKLE-2. By using time-lapse video microscopy, we show that absence of this protein severely compromises the post mitotic re-association of the nuclear proteins BAF, LAP2α and LaminA to chromosomes. These defects give rise to a strong mechanical instability of the nuclear envelope in telophase and to a chromosomal instability leading to increased number of hyperploid cells. Reintroducing LEM4/ANKLE-2 in the cells by transfection could efficiently restore the telophase association of BAF and LAP2α to the chromosomes. This rescue phenotype was abolished for N- or C-terminally truncated mutants that had lost the capacity to bind PP2A. We demonstrate also that, in addition to binding to PP2A, LEM4/ANKLE-2 binds BAF through its LEM-domain, providing further evidence for a generic function of this domain as a principal interactor of BAF.
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Affiliation(s)
- Luc Snyers
- Department of Cell and Developmental Biology, Center for Anatomy and Cell Biology, Medical University of Vienna, Schwarzspanierstrasse 17, Vienna, 1090, Austria.
| | - Renate Erhart
- Department of Cell and Developmental Biology, Center for Anatomy and Cell Biology, Medical University of Vienna, Schwarzspanierstrasse 17, Vienna, 1090, Austria
| | - Sylvia Laffer
- Department of Cell and Developmental Biology, Center for Anatomy and Cell Biology, Medical University of Vienna, Schwarzspanierstrasse 17, Vienna, 1090, Austria
| | - Oliver Pusch
- Department of Cell and Developmental Biology, Center for Anatomy and Cell Biology, Medical University of Vienna, Schwarzspanierstrasse 17, Vienna, 1090, Austria
| | - Klara Weipoltshammer
- Department of Cell and Developmental Biology, Center for Anatomy and Cell Biology, Medical University of Vienna, Schwarzspanierstrasse 17, Vienna, 1090, Austria
| | - Christian Schöfer
- Department of Cell and Developmental Biology, Center for Anatomy and Cell Biology, Medical University of Vienna, Schwarzspanierstrasse 17, Vienna, 1090, Austria
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79
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Johnston APR, Rae J, Ariotti N, Bailey B, Lilja A, Webb R, Ferguson C, Maher S, Davis TP, Webb RI, McGhee J, Parton RG. Journey to the centre of the cell: Virtual reality immersion into scientific data. Traffic 2017; 19:105-110. [PMID: 29159991 DOI: 10.1111/tra.12538] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Revised: 10/31/2017] [Accepted: 10/31/2017] [Indexed: 01/13/2023]
Abstract
Visualization of scientific data is crucial not only for scientific discovery but also to communicate science and medicine to both experts and a general audience. Until recently, we have been limited to visualizing the three-dimensional (3D) world of biology in 2 dimensions. Renderings of 3D cells are still traditionally displayed using two-dimensional (2D) media, such as on a computer screen or paper. However, the advent of consumer grade virtual reality (VR) headsets such as Oculus Rift and HTC Vive means it is now possible to visualize and interact with scientific data in a 3D virtual world. In addition, new microscopic methods provide an unprecedented opportunity to obtain new 3D data sets. In this perspective article, we highlight how we have used cutting edge imaging techniques to build a 3D virtual model of a cell from serial block-face scanning electron microscope (SBEM) imaging data. This model allows scientists, students and members of the public to explore and interact with a "real" cell. Early testing of this immersive environment indicates a significant improvement in students' understanding of cellular processes and points to a new future of learning and public engagement. In addition, we speculate that VR can become a new tool for researchers studying cellular architecture and processes by populating VR models with molecular data.
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Affiliation(s)
- Angus P R Johnston
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Australia.,ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash University, Parkville, Australia
| | - James Rae
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Australia.,ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, University of Queensland, Brisbane, Australia
| | - Nicholas Ariotti
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Australia
| | - Benjamin Bailey
- 3D Visualisation Aesthetics Lab, University of New South Wales, Sydney, Australia.,ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, University of New South Wales, Sydney, Australia
| | - Andrew Lilja
- 3D Visualisation Aesthetics Lab, University of New South Wales, Sydney, Australia.,ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, University of New South Wales, Sydney, Australia
| | - Robyn Webb
- Centre for Microscopy and Microanalysis, University of Queensland, Brisbane, Australia
| | - Charles Ferguson
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Australia.,ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, University of Queensland, Brisbane, Australia
| | - Sheryl Maher
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Australia
| | - Thomas P Davis
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Australia.,ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash University, Parkville, Australia.,Department of Chemistry, University of Warwick, Coventry, UK
| | - Richard I Webb
- Centre for Microscopy and Microanalysis, University of Queensland, Brisbane, Australia
| | - John McGhee
- 3D Visualisation Aesthetics Lab, University of New South Wales, Sydney, Australia.,ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, University of New South Wales, Sydney, Australia
| | - Robert G Parton
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Australia.,ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, University of Queensland, Brisbane, Australia.,Centre for Microscopy and Microanalysis, University of Queensland, Brisbane, Australia
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80
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Qiu S, Leung A, Bo Y, Kozak RA, Anand SP, Warkentin C, Salambanga FDR, Cui J, Kobinger G, Kobasa D, Côté M. Ebola virus requires phosphatidylinositol (3,5) bisphosphate production for efficient viral entry. Virology 2017; 513:17-28. [PMID: 29031163 DOI: 10.1016/j.virol.2017.09.028] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 09/28/2017] [Accepted: 09/30/2017] [Indexed: 12/11/2022]
Abstract
For entry, Ebola virus (EBOV) requires the interaction of its viral glycoprotein with the cellular protein Niemann-Pick C1 (NPC1) which resides in late endosomes and lysosomes. How EBOV is trafficked and delivered to NPC1 and whether this is positively regulated during entry remain unclear. Here, we show that the PIKfyve-ArPIKfyve-Sac3 cellular complex, which is involved in the metabolism of phosphatidylinositol (3,5) bisphosphate (PtdIns(3,5)P2), is critical for EBOV infection. Although the expression of all subunits of the complex was required for efficient entry, PIKfyve kinase activity was specifically critical for entry by all pathogenic filoviruses. Inhibition of PIKfyve prevented colocalization of EBOV with NPC1 and led to virus accumulation in intracellular vesicles with characteristics of early endosomes. Importantly, genetically-encoded phosphoinositide probes revealed an increase in PtdIns(3,5)P2-positive vesicles in cells during EBOV entry. Taken together, our studies suggest that EBOV requires PtdIns(3,5)P2 production in cells to promote efficient delivery to NPC1.
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Affiliation(s)
- Shirley Qiu
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Canada; Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, Canada
| | - Anders Leung
- Special Pathogens Program, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Canada
| | - Yuxia Bo
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Canada; Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, Canada
| | - Robert A Kozak
- Special Pathogens Program, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Canada
| | - Sai Priya Anand
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Canada; Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, Canada
| | - Corina Warkentin
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Canada; Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, Canada
| | - Fabiola D R Salambanga
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Canada; Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, Canada
| | - Jennifer Cui
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Canada; Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, Canada
| | - Gary Kobinger
- Special Pathogens Program, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Canada
| | - Darwyn Kobasa
- Special Pathogens Program, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Canada; Department of Medical Microbiology, University of Manitoba, Winnipeg, Canada
| | - Marceline Côté
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Canada; Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, Canada.
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81
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ORP5 and ORP8 bind phosphatidylinositol-4, 5-biphosphate (PtdIns(4,5)P 2) and regulate its level at the plasma membrane. Nat Commun 2017; 8:757. [PMID: 28970484 PMCID: PMC5624964 DOI: 10.1038/s41467-017-00861-5] [Citation(s) in RCA: 137] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 08/02/2017] [Indexed: 12/20/2022] Open
Abstract
ORP5 and ORP8, members of the oxysterol-binding protein (OSBP)-related proteins (ORP) family, are endoplasmic reticulum membrane proteins implicated in lipid trafficking. ORP5 and ORP8 are reported to localize to endoplasmic reticulum–plasma membrane junctions via binding to phosphatidylinositol-4-phosphate (PtdIns(4)P), and act as a PtdIns(4)P/phosphatidylserine counter exchanger between the endoplasmic reticulum and plasma membrane. Here we provide evidence that the pleckstrin homology domain of ORP5/8 via PtdIns(4,5)P2, and not PtdIns(4)P binding mediates the recruitment of ORP5/8 to endoplasmic reticulum–plasma membrane contact sites. The OSBP-related domain of ORP8 can extract and transport multiple phosphoinositides in vitro, and knocking down both ORP5 and ORP8 in cells increases the plasma membrane level of PtdIns(4,5)P2 with little effect on PtdIns(4)P. Overall, our data show, for the first time, that phosphoinositides other than PtdIns(4)P can also serve as co-exchangers for the transport of cargo lipids by ORPs. ORP5/8 are endoplasmic reticulum (ER) membrane proteins implicated in lipid trafficking that localize to ER-plasma membrane (PM) contacts and maintain membrane homeostasis. Here the authors show that PtdIns(4,5)P2 plays a critical role in the targeting and function of ORP5/8 at the PM.
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82
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Electron microscopy using the genetically encoded APEX2 tag in cultured mammalian cells. Nat Protoc 2017; 12:1792-1816. [PMID: 28796234 DOI: 10.1038/nprot.2017.065] [Citation(s) in RCA: 122] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Electron microscopy (EM) is the premiere technique for high-resolution imaging of cellular ultrastructure. Unambiguous identification of specific proteins or cellular compartments in electron micrographs, however, remains challenging because of difficulties in delivering electron-dense contrast agents to specific subcellular targets within intact cells. We recently reported enhanced ascorbate peroxidase 2 (APEX2) as a broadly applicable genetic tag that generates EM contrast on a specific protein or subcellular compartment of interest. This protocol provides guidelines for designing and validating APEX2 fusion constructs, along with detailed instructions for cell culture, transfection, fixation, heavy-metal staining, embedding in resin, and EM imaging. Although this protocol focuses on EM in cultured mammalian cells, APEX2 is applicable to many cell types and contexts, including intact tissues and organisms, and is useful for numerous applications beyond EM, including live-cell proteomic mapping. This protocol, which describes procedures for sample preparation from cell monolayers and cell pellets, can be completed in 10 d, including time for APEX2 fusion construct validation, cell growth, and solidification of embedding resins. Notably, the only additional steps required relative to a standard EM sample preparation are cell transfection and a 2- to 45-min staining period with 3,3-diaminobenzidine (DAB) and hydrogen peroxide (H2O2).
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83
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84
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Wobst HJ, Delsing L, Brandon NJ, Moss SJ. Truncation of the TAR DNA-binding protein 43 is not a prerequisite for cytoplasmic relocalization, and is suppressed by caspase inhibition and by introduction of the A90V sequence variant. PLoS One 2017; 12:e0177181. [PMID: 28510586 PMCID: PMC5433705 DOI: 10.1371/journal.pone.0177181] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Accepted: 04/23/2017] [Indexed: 12/12/2022] Open
Abstract
The RNA-binding and -processing protein TAR DNA-binding protein 43 (TDP-43) is heavily linked to the underlying causes and pathology of neurodegenerative diseases such as amyotrophic lateral sclerosis and frontotemporal lobar degeneration. In these diseases, TDP-43 is mislocalized, hyperphosphorylated, ubiquitinated, aggregated and cleaved. The importance of TDP-43 cleavage in the disease pathogenesis is still poorly understood. Here we detail the use of D-sorbitol as an exogenous stressor that causes TDP-43 cleavage in HeLa cells, resulting in a 35 kDa truncated product that accumulates in the cytoplasm within one hour of treatment. We confirm that the formation of this 35 kDa cleavage product is mediated by the activation of caspases. Inhibition of caspases blocks the cleavage of TDP-43, but does not prevent the accumulation of full-length protein in the cytoplasm. Using D-sorbitol as a stressor and caspase activator, we also demonstrate that the A90V variant of TDP-43, which lies adjacent to the caspase cleavage site within the nuclear localization sequence of TDP-43, confers partial resistance against caspase-mediated generation of the 35 kDa cleavage product.
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Affiliation(s)
- Heike J. Wobst
- AstraZeneca-Tufts Laboratory for Basic and Translational Neuroscience, Tufts University, Boston, MA, United States of America
| | - Louise Delsing
- AstraZeneca-Tufts Laboratory for Basic and Translational Neuroscience, Tufts University, Boston, MA, United States of America
- AstraZeneca, Discovery Science, Innovative Medicines and Early Development Biotech Unit, Mölndal, Sweden
| | - Nicholas J. Brandon
- AstraZeneca-Tufts Laboratory for Basic and Translational Neuroscience, Tufts University, Boston, MA, United States of America
- AstraZeneca, Neuroscience, Innovative Medicines and Early Development, Waltham, MA, United States of America
| | - Stephen J. Moss
- AstraZeneca-Tufts Laboratory for Basic and Translational Neuroscience, Tufts University, Boston, MA, United States of America
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA, United States of America
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85
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Ariotti N, Hall TE, Parton RG. Correlative light and electron microscopic detection of GFP-labeled proteins using modular APEX. Methods Cell Biol 2017; 140:105-121. [PMID: 28528629 DOI: 10.1016/bs.mcb.2017.03.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/01/2023]
Abstract
The use of green fluorescent protein (GFP) and related proteins has revolutionized light microscopy. Here we describe a rapid and simple method to localize GFP-tagged proteins in cells and in tissues by electron microscopy (EM) using a modular approach involving a small GFP-binding peptide (GBP) fused to the ascorbate peroxidase-derived APEX2 tag. We provide a method for visualizing GFP-tagged proteins by light and EM in cultured cells and in the zebrafish using modular APEX-GBP. Furthermore, we describe in detail the benefits of this technique over many of the currently available correlative light and electron microscopy approaches and demonstrate APEX-GBP is readily applicable to modern three-dimensional techniques.
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Affiliation(s)
| | - Thomas E Hall
- The University of Queensland, Brisbane, QLD, Australia
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86
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Hawley TS, Hawley RG, Telford WG. Fluorescent Proteins for Flow Cytometry. ACTA ACUST UNITED AC 2017; 80:9.12.1-9.12.20. [PMID: 28369764 DOI: 10.1002/cpcy.17] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Fluorescent proteins have become standard tools for cell and molecular biologists. The color palette of fluorescent proteins spans the ultraviolet, visible, and near-infrared spectrum. Utility of fluorescent proteins has been greatly facilitated by the availability of compact and affordable solid state lasers capable of providing various excitation wavelengths. In theory, the plethora of fluorescent proteins and lasers make it easy to detect multiple fluorescent proteins simultaneously. However, in practice, heavy spectral overlap due to broad excitation and emission spectra presents a challenge. In conventional flow cytometry, careful selection of excitation wavelengths and detection filters is necessary. Spectral flow cytometry, an emerging methodology that is not confined by the "one color, one detector" paradigm, shows promise in the facile detection of multiple fluorescent proteins. This chapter provides a synopsis of fluorescent protein development, a list of commonly used fluorescent proteins, some practical considerations and strategies for detection, and examples of applications. © 2017 by John Wiley & Sons, Inc.
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Affiliation(s)
- Teresa S Hawley
- Flow Cytometry Core Facility, Laboratory of Genome Integrity, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland
| | - Robert G Hawley
- Department of Anatomy and Regenerative Biology, George Washington University School of Medicine and Health Sciences, Washington, D.C
| | - William G Telford
- Flow Cytometry Core Facility, Experimental Transplantation and Immunology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland
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87
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Liu LK, Choudhary V, Toulmay A, Prinz WA. An inducible ER-Golgi tether facilitates ceramide transport to alleviate lipotoxicity. J Cell Biol 2016; 216:131-147. [PMID: 28011845 PMCID: PMC5223604 DOI: 10.1083/jcb.201606059] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Revised: 10/20/2016] [Accepted: 12/07/2016] [Indexed: 01/27/2023] Open
Abstract
Liu et al. show that ER–Golgi tethering increases during ER stress in yeast. The protein Nvj2p is required for this tethering, which promotes nonvesicular ceramide transport from the ER to the Golgi to alleviate ceramide toxicity. Ceramides are key intermediates in sphingolipid biosynthesis and potent signaling molecules. However, excess ceramide is toxic, causing growth arrest and apoptosis. In this study, we identify a novel mechanism by which cells prevent the toxic accumulation of ceramides; they facilitate nonvesicular ceramide transfer from the endoplasmic reticulum (ER) to the Golgi complex, where ceramides are converted to complex sphingolipids. We find that the yeast protein Nvj2p promotes the nonvesicular transfer of ceramides from the ER to the Golgi complex. The protein is a tether that generates close contacts between these compartments and may directly transport ceramide. Nvj2p normally resides at contacts between the ER and other organelles, but during ER stress, it relocalizes to and increases ER–Golgi contacts. ER–Golgi contacts fail to form during ER stress in cells lacking Nvj2p. Our findings demonstrate that cells regulate ER–Golgi contacts in response to stress and reveal that nonvesicular ceramide transfer out of the ER prevents the buildup of toxic amounts of ceramides.
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Affiliation(s)
- Li-Ka Liu
- Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Vineet Choudhary
- Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Alexandre Toulmay
- Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892
| | - William A Prinz
- Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892
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88
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Karreman MA, Hyenne V, Schwab Y, Goetz JG. Intravital Correlative Microscopy: Imaging Life at the Nanoscale. Trends Cell Biol 2016; 26:848-863. [DOI: 10.1016/j.tcb.2016.07.003] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 07/12/2016] [Accepted: 07/15/2016] [Indexed: 01/04/2023]
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89
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Follett J, Bugarcic A, Yang Z, Ariotti N, Norwood SJ, Collins BM, Parton RG, Teasdale RD. Parkinson Disease-linked Vps35 R524W Mutation Impairs the Endosomal Association of Retromer and Induces α-Synuclein Aggregation. J Biol Chem 2016; 291:18283-98. [PMID: 27385586 DOI: 10.1074/jbc.m115.703157] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Indexed: 12/20/2022] Open
Abstract
Endosomal sorting is a highly orchestrated cellular process. Retromer is a heterotrimeric complex that associates with endosomal membranes and facilitates the retrograde sorting of multiple receptors, including the cation-independent mannose 6-phosphate receptor for lysosomal enzymes. The cycling of retromer on and off the endosomal membrane is regulated by a network of retromer-interacting proteins. Here, we find that Parkinson disease-associated Vps35 variant, R524W, but not P316S, is a loss-of-function mutation as marked by a reduced association with this regulatory network and dysregulation of endosomal receptor sorting. Expression of Vps35 R524W-containing retromer results in the accumulation of intracellular α-synuclein-positive aggregates, a hallmark of Parkinson disease. Overall, the Vps35 R524W-containing retromer has a decreased endosomal association, which can be partially rescued by R55, a small molecule previously shown to stabilize the retromer complex, supporting the potential for future targeting of the retromer complex in the treatment of Parkinson disease.
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Affiliation(s)
- Jordan Follett
- From the Institute for Molecular Bioscience, University of Queensland, St. Lucia, Queensland 4072, Australia and
| | - Andrea Bugarcic
- From the Institute for Molecular Bioscience, University of Queensland, St. Lucia, Queensland 4072, Australia and
| | - Zhe Yang
- From the Institute for Molecular Bioscience, University of Queensland, St. Lucia, Queensland 4072, Australia and
| | - Nicholas Ariotti
- From the Institute for Molecular Bioscience, University of Queensland, St. Lucia, Queensland 4072, Australia and
| | - Suzanne J Norwood
- From the Institute for Molecular Bioscience, University of Queensland, St. Lucia, Queensland 4072, Australia and
| | - Brett M Collins
- From the Institute for Molecular Bioscience, University of Queensland, St. Lucia, Queensland 4072, Australia and
| | - Robert G Parton
- From the Institute for Molecular Bioscience, University of Queensland, St. Lucia, Queensland 4072, Australia and the Centre for Microscopy and Microanalysis, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Rohan D Teasdale
- From the Institute for Molecular Bioscience, University of Queensland, St. Lucia, Queensland 4072, Australia and
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90
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Hall TE, Ariotti N, Ferguson C, Xiong Z, Parton RG. New Transgenic Lines for Localization of GFP-Tagged Proteins by Electron Microscopy. Zebrafish 2016; 13:232-3. [DOI: 10.1089/zeb.2016.29002.hal] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Thomas E. Hall
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Australia
| | - Nicholas Ariotti
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Australia
| | - Charles Ferguson
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Australia
| | - Zherui Xiong
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Australia
| | - Robert G. Parton
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Australia
- Centre for Microscopy and Microanalysis, University of Queensland, Brisbane, Australia
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91
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A localization module. Nat Chem Biol 2015. [DOI: 10.1038/nchembio.1994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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