1
|
Sadeghi N, Kok RJ, Bos C, Zandvliet M, Geerts WJC, Storm G, Moonen CTW, Lammers T, Deckers R. Hyperthermia-triggered release of hypoxic cell radiosensitizers from temperature-sensitive liposomes improves radiotherapy efficacy in vitro. Nanotechnology 2019; 30:264001. [PMID: 30836341 DOI: 10.1088/1361-6528/ab0ce6] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Hypoxia is a characteristic feature of solid tumors and an important cause of resistance to radiotherapy. Hypoxic cell radiosensitizers have been shown to increase radiotherapy efficacy, but dose-limiting side effects prevent their widespread use in the clinic. We propose the encapsulation of hypoxic cell radiosensitizers in temperature-sensitive liposomes (TSL) to target the radiosensitizers specifically to tumors and to avoid unwanted accumulation in healthy tissues. The main objective of the present study is to develop and characterize TSL loaded with the radiosensitizer pimonidazole (PMZ) and to evaluate the in vitro efficacy of free PMZ and PMZ encapsulated in TSL in combination with hyperthermia and radiotherapy. PMZ was actively loaded into TSL at different drug/lipid ratios, and the physicochemical characteristics and the stability of the resulting TSL-PMZ were evaluated. PMZ release was determined at 37 °C and 42 °C in HEPES buffer saline and fetal bovine serum. The concentration-dependent radiosensitizing effect of PMZ was investigated by exposing FaDu cells to different PMZ concentrations under hypoxic conditions followed by exposure to ionizing irradiation. The efficacy of TSL-PMZ in combination with hyperthermia and radiotherapy was determined in vitro, assessing cell survival and DNA damage by means of the clonogenic assay and histone H2AX phosphorylation, respectively. All TSL-PMZ formulations showed high encapsulation efficiencies and were stable for 30 d upon storage at 4 °C and 20 °C. Fast PMZ release was observed at 42 °C, regardless of the drug/lipid ratio. Increasing the PMZ concentration significantly enhanced the effect of ionizing irradiation. Pre-heated TSL-PMZ in combination with radiotherapy caused a 14.3-fold increase in cell death as compared to radiotherapy treatment alone. In conclusion, our results indicate that TSL-PMZ in combination with hyperthermia can assist in improving the efficacy of radiotherapy under hypoxic conditions.
Collapse
Affiliation(s)
- Negar Sadeghi
- Imaging Division, University Medical Center Utrecht, Utrecht, The Netherlands. Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands. Department of Nanomedicine and Theranostics, Institute for Experimental Molecular Imaging, University Clinic and Helmholtz Institute for Biomedical Engineering, RWTH Aachen University, Aachen, Germany
| | | | | | | | | | | | | | | | | |
Collapse
|
2
|
Abstract
Blood platelets play a central role in the arrest of bleeding and the development of thrombosis. Unraveling the complex processes of platelet biogenesis from megakaryocytes, platelet adhesion, aggregation, and secretory responses are important topics in the field of hemostasis and thrombosis. Analysis of the ultrastructural changes that occur during these processes is essential for understanding the rapid membrane dynamics and has contributed substantially to our present knowledge of platelet formation and functioning. Recent developments in real-time imaging, correlative light and electron microscopy imaging (CLEM), and 3D (cryo) electron microscopy and tomography offer exciting opportunities to improve studies of the platelet adhesive responses and secretion at the ultrastructural level in a close to native environment. In this chapter we discuss and illustrate cryo preparation techniques (high-pressure freezing, vitrification), correlative LM and EM workflows, and 3D cryo-electron tomography that we apply in our current research projects.
Collapse
Affiliation(s)
- Kasia B Engberts
- Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, The Netherlands
| | - Cor Seinen
- Laboratory of Clinical Chemistry and Hematology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Willie J C Geerts
- Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, The Netherlands
| | - Harry F G Heijnen
- Laboratory of Clinical Chemistry and Hematology, University Medical Center Utrecht, Utrecht, The Netherlands. .,Department of Cell Biology, Cell Microscopy Core, University Medical Center Utrecht, Utrecht, The Netherlands.
| |
Collapse
|
3
|
Kaplan M, Narasimhan S, de Heus C, Mance D, van Doorn S, Houben K, Popov-Čeleketić D, Damman R, Katrukha EA, Jain P, Geerts WJC, Heck AJR, Folkers GE, Kapitein LC, Lemeer S, van Bergen En Henegouwen PMP, Baldus M. EGFR Dynamics Change during Activation in Native Membranes as Revealed by NMR. Cell 2016; 167:1241-1251.e11. [PMID: 27839865 DOI: 10.1016/j.cell.2016.10.038] [Citation(s) in RCA: 126] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Revised: 08/08/2016] [Accepted: 10/20/2016] [Indexed: 10/20/2022]
Abstract
The epidermal growth factor receptor (EGFR) represents one of the most common target proteins in anti-cancer therapy. To directly examine the structural and dynamical properties of EGFR activation by the epidermal growth factor (EGF) in native membranes, we have developed a solid-state nuclear magnetic resonance (ssNMR)-based approach supported by dynamic nuclear polarization (DNP). In contrast to previous crystallographic results, our experiments show that the ligand-free state of the extracellular domain (ECD) is highly dynamic, while the intracellular kinase domain (KD) is rigid. Ligand binding restricts the overall and local motion of EGFR domains, including the ECD and the C-terminal region. We propose that the reduction in conformational entropy of the ECD by ligand binding favors the cooperative binding required for receptor dimerization, causing allosteric activation of the intracellular tyrosine kinase.
Collapse
Affiliation(s)
- Mohammed Kaplan
- NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Siddarth Narasimhan
- NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Cecilia de Heus
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Deni Mance
- NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Sander van Doorn
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Klaartje Houben
- NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Dušan Popov-Čeleketić
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Reinier Damman
- NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Eugene A Katrukha
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Purvi Jain
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Willie J C Geerts
- Biomolecular Imaging, Bijvoet Center for Biomolecular Research, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Albert J R Heck
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Gert E Folkers
- NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Lukas C Kapitein
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Simone Lemeer
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, 3584 CH Utrecht, the Netherlands
| | | | - Marc Baldus
- NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Utrecht University, 3584 CH Utrecht, the Netherlands.
| |
Collapse
|
4
|
Groot Kormelink T, Arkesteijn GJA, van de Lest CHA, Geerts WJC, Goerdayal SS, Altelaar MAF, Redegeld FA, Nolte-'t Hoen ENM, Wauben MHM. Mast Cell Degranulation Is Accompanied by the Release of a Selective Subset of Extracellular Vesicles That Contain Mast Cell-Specific Proteases. J Immunol 2016; 197:3382-3392. [PMID: 27619994 DOI: 10.4049/jimmunol.1600614] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 08/12/2016] [Indexed: 12/21/2022]
Abstract
Mast cells (MC) are well known for their effector role in allergic disorders; moreover, they are associated with diverse modulatory effects in innate and adaptive immunity. It is largely unclear how MC exert these modulating functions. In this article, we show that IgE-mediated MC degranulation leads to a rapid release of high quantities of extracellular vesicles (EV), comparable to the release of preformed mediators. EV are submicron structures composed of lipid bilayers, proteins, and nucleic acids that are released by cells in a regulated fashion and are involved in intercellular communication. Primary murine mucosal-type MC and connective tissue-type MC released phenotypically different EV populations depending on the stimulus they received. Although unstimulated MC constitutively released CD9+ EV, degranulation was accompanied by the release of CD63+ EV, which correlated with release of the soluble mediator β-hexosaminidase. This CD63+ EV subset was smaller and exhibited a higher buoyant density and distinct phospholipid composition compared with CD9+ EV. Marked differences were observed for phosphatidylinositol, phosphatidic acid, and bis(monoacylglycero)phosphate species. Strikingly, proteomic analysis of CD63+ EV from connective tissue-type MC unveiled an abundance of MC-specific proteases. With regard to carboxypeptidase A3, it was confirmed that the enzyme was EV associated and biologically active. Our data demonstrate that, depending on their activation status, MC release distinct EV subsets that differ in composition and protease activity and are indicative of differential immunological functions. Concerning the strategic tissue distribution of MC and the presence of degranulated MC in various (allergic) disorders, MC-derived EV should be considered potentially important immune regulators.
Collapse
Affiliation(s)
- Tom Groot Kormelink
- Department of Biochemistry and Cell Biology, Faculty of Veterinary Medicine, Utrecht University, 3584 CM Utrecht, the Netherlands;
| | - Ger J A Arkesteijn
- Department of Biochemistry and Cell Biology, Faculty of Veterinary Medicine, Utrecht University, 3584 CM Utrecht, the Netherlands.,Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, 3584 CL Utrecht, the Netherlands
| | - Chris H A van de Lest
- Department of Biochemistry and Cell Biology, Faculty of Veterinary Medicine, Utrecht University, 3584 CM Utrecht, the Netherlands
| | - Willie J C Geerts
- Biomolecular Imaging, Bijvoet Center, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Soenita S Goerdayal
- Biomolecular Mass Spectrometry and Proteomics Group, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, 3584 CH Utrecht, the Netherlands; and
| | - Maarten A F Altelaar
- Biomolecular Mass Spectrometry and Proteomics Group, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, 3584 CH Utrecht, the Netherlands; and
| | - Frank A Redegeld
- Division of Pharmacology, Department of Pharmaceutical Sciences, Faculty of Science, Utrecht University, 3584 CG Utrecht, the Netherlands
| | - Esther N M Nolte-'t Hoen
- Department of Biochemistry and Cell Biology, Faculty of Veterinary Medicine, Utrecht University, 3584 CM Utrecht, the Netherlands
| | - Marca H M Wauben
- Department of Biochemistry and Cell Biology, Faculty of Veterinary Medicine, Utrecht University, 3584 CM Utrecht, the Netherlands
| |
Collapse
|
5
|
Boere J, van de Lest CHA, Libregts SFWM, Arkesteijn GJA, Geerts WJC, Nolte-'t Hoen ENM, Malda J, van Weeren PR, Wauben MHM. Synovial fluid pretreatment with hyaluronidase facilitates isolation of CD44+ extracellular vesicles. J Extracell Vesicles 2016; 5:31751. [PMID: 27511891 PMCID: PMC4980521 DOI: 10.3402/jev.v5.31751] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Revised: 06/07/2016] [Accepted: 07/03/2016] [Indexed: 12/14/2022] Open
Abstract
Extracellular vesicles (EVs) in synovial fluid (SF) are gaining increased recognition as important factors in joint homeostasis, joint regeneration, and as biomarkers of joint disease. A limited number of studies have investigated EVs in SF samples of patients with joint disease, but knowledge on the role of EVs in healthy joints is lacking. In addition, no standardized protocol is available for isolation of EVs from SF. Based on the high viscosity of SF caused by high concentrations of hyaluronic acid (HA) - a prominent extracellular matrix component - it was hypothesized that EV recovery could be optimized by pretreatment with hyaluronidase (HYase). Therefore, the efficiency of EV isolation from healthy equine SF samples was tested by performing sequential ultracentrifugation steps (10,000g, 100,000g and 200,000g) in the presence or absence of HYase. Quantitative EV analysis using high-resolution flow cytometry showed an efficient recovery of EVs after 100,000g ultracentrifugation, with an increased yield of CD44+ EVs when SF samples were pretreated with HYase. Morphological analysis of SF-derived EVs with cryo-transmission-electron microscopy did not indicate damage by high-speed ultracentrifugation and revealed that most EVs are spherical with a diameter of 20-200 nm. Further protein characterization by Western blotting revealed that healthy SF-derived EVs contain CD9, Annexin-1, and CD90/Thy1.1. Taken together, these data suggest that EV isolation protocols for body fluids that contain relatively high amounts of HA, such as SF, could benefit from treatment of the fluid with HYase prior to ultracentrifugation. This method facilitates recovery and detection of CD44+ EVs within the HA-rich extracellular matrix. Furthermore, based on the findings presented here, it is recommended to sediment SF-derived EVs with at least 100,000g for optimal EV recovery.
Collapse
Affiliation(s)
- Janneke Boere
- Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, Netherlands.,Department of Biochemistry and Cell Biology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, Netherlands.,Department of Orthopaedics, University Medical Center Utrecht, Utrecht, Netherlands
| | - Chris H A van de Lest
- Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, Netherlands.,Department of Biochemistry and Cell Biology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, Netherlands
| | - Sten F W M Libregts
- Department of Biochemistry and Cell Biology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, Netherlands
| | - Ger J A Arkesteijn
- Department of Biochemistry and Cell Biology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, Netherlands.,Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, Netherlands
| | - Willie J C Geerts
- Department of Cryo-Electron Microscopy, Bijvoet Center for Biomolecular Research, Utrecht, Netherlands
| | - Esther N M Nolte-'t Hoen
- Department of Biochemistry and Cell Biology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, Netherlands
| | - Jos Malda
- Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, Netherlands.,Department of Orthopaedics, University Medical Center Utrecht, Utrecht, Netherlands
| | - P René van Weeren
- Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, Netherlands
| | - Marca H M Wauben
- Department of Biochemistry and Cell Biology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, Netherlands;
| |
Collapse
|
6
|
Lorenzato C, Oerlemans C, van Elk M, Geerts WJC, Denis de Senneville B, Moonen C, Bos C. MRI monitoring of nanocarrier accumulation and release using Gadolinium-SPIO co-labelled thermosensitive liposomes. Contrast Media Mol Imaging 2016; 11:184-94. [PMID: 26750715 DOI: 10.1002/cmmi.1679] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Revised: 10/09/2015] [Accepted: 11/19/2015] [Indexed: 12/20/2022]
Abstract
Encapsulation of anticancer drugs in triggerable nanocarriers can beneficially modify pharmacokinetics and biodistribution of chemotherapeutic drugs, and consequently increase tumor drug concentration and efficacy, while reducing side effects. Thermosensitive liposomes release their contents triggered by hyperthermia, which can be, for example, precisely delivered using an MR Imaging-guided focused ultrasound procedure. In such a scenario, it is attractive to demonstrate the accumulation of liposomes before applying hyperthermia, as well as to document the release of liposome content using MRI. To address this need, thermosensitive liposomes were developed and characterized, which were doubly loaded by iron oxide nanoparticles and Gd-chelate, as opposed to loading with a single contrast agent. When intact, the transverse relaxivity of the liposomes is high allowing detection of carriers in tissue. After heating the longitudinal relaxivity steeply increases indicating release of the small molecular contents. By choosing the appropriate MR sequences, availability and release can be evaluated without interference of one contrast agent with the other. Copyright © 2016 John Wiley & Sons, Ltd.
Collapse
Affiliation(s)
- Cyril Lorenzato
- University Medical Center Utrecht, Department of Radiology, Imaging Division, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands
| | - Chris Oerlemans
- University Medical Center Utrecht, Department of Radiology, Imaging Division, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands
| | - Merel van Elk
- Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences, 3584 CG, Utrecht, The Netherlands
| | - Willie J C Geerts
- Biomolecular Imaging, Bijvoet Center, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands
| | - Baudouin Denis de Senneville
- University Medical Center Utrecht, Department of Radiology, Imaging Division, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands.,Institut de Mathématiques de Bordeaux, UMR 5251 CNRS/Université de Bordeaux, F-33400, Talence, France
| | - Chrit Moonen
- University Medical Center Utrecht, Department of Radiology, Imaging Division, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands
| | - Clemens Bos
- University Medical Center Utrecht, Department of Radiology, Imaging Division, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands
| |
Collapse
|
7
|
Beznoussenko GV, Pilyugin SS, Geerts WJC, Kozlov MM, Burger KNJ, Luini A, Derganc J, Mironov AA. Trans-membrane area asymmetry controls the shape of cellular organelles. Int J Mol Sci 2015; 16:5299-333. [PMID: 25761238 PMCID: PMC4394477 DOI: 10.3390/ijms16035299] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Revised: 02/04/2015] [Accepted: 02/13/2015] [Indexed: 01/08/2023] Open
Abstract
Membrane organelles often have complicated shapes and differ in their volume, surface area and membrane curvature. The ratio between the surface area of the cytosolic and luminal leaflets (trans-membrane area asymmetry (TAA)) determines the membrane curvature within different sites of the organelle. Thus, the shape of the organelle could be critically dependent on TAA. Here, using mathematical modeling and stereological measurements of TAA during fast transformation of organelle shapes, we present evidence that suggests that when organelle volume and surface area are constant, TAA can regulate transformation of the shape of the Golgi apparatus, endosomal multivesicular bodies, and microvilli of brush borders of kidney epithelial cells. Extraction of membrane curvature by small spheres, such as COPI-dependent vesicles within the Golgi (extraction of positive curvature), or by intraluminal vesicles within endosomes (extraction of negative curvature) controls the shape of these organelles. For instance, Golgi tubulation is critically dependent on the fusion of COPI vesicles with Golgi cisternae, and vice versa, for the extraction of membrane curvature into 50–60 nm vesicles, to induce transformation of Golgi tubules into cisternae. Also, formation of intraluminal ultra-small vesicles after fusion of endosomes allows equilibration of their TAA, volume and surface area. Finally, when microvilli of the brush border are broken into vesicles and microvilli fragments, TAA of these membranes remains the same as TAA of the microvilli. Thus, TAA has a significant role in transformation of organelle shape when other factors remain constant.
Collapse
Affiliation(s)
- Galina V Beznoussenko
- The FIRC Institute of Molecular Oncology, Milan 20139, Italy.
- Consorzio Mario Negri Sud, S. Maria Imbaro, Chieti 66030, Italy.
| | - Sergei S Pilyugin
- Department of Mathematics, University of Florida, Gainesville, FL 32611-8105, USA.
| | - Willie J C Geerts
- Department of Biochemical Physiology, Institute of Biomembranes, 3584 CH Utrecht, The Netherlands.
| | - Michael M Kozlov
- Department of Physiology and Pharmacology, Tel Aviv University, Tel Aviv 69978, Israel.
| | - Koert N J Burger
- Department of Biochemical Physiology, Institute of Biomembranes, 3584 CH Utrecht, The Netherlands.
| | - Alberto Luini
- Consiglio Nazionale delle Ricerche (CNR), Istituto di Biochimica delle Proteine, Naples 80131, Italy.
| | - Jure Derganc
- Institute of Biophysics, University of Ljubljana, 1000 Ljubljana, Slovenia.
| | - Alexander A Mironov
- The FIRC Institute of Molecular Oncology, Milan 20139, Italy.
- Consorzio Mario Negri Sud, S. Maria Imbaro, Chieti 66030, Italy.
| |
Collapse
|
8
|
Delevoye C, Hurbain I, Tenza D, Sibarita JB, Uzan-Gafsou S, Ohno H, Geerts WJC, Verkleij AJ, Salamero J, Marks MS, Raposo G. AP-1 and KIF13A coordinate endosomal sorting and positioning during melanosome biogenesis. ACTA ACUST UNITED AC 2009; 187:247-64. [PMID: 19841138 PMCID: PMC2768840 DOI: 10.1083/jcb.200907122] [Citation(s) in RCA: 137] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Specialized cell types exploit endosomal trafficking to deliver protein cargoes to cell type-specific lysosome-related organelles (LROs), but how endosomes are specified for this function is not known. In this study, we show that the clathrin adaptor AP-1 and the kinesin motor KIF13A together create peripheral recycling endosomal subdomains in melanocytes required for cargo delivery to maturing melanosomes. In cells depleted of AP-1 or KIF13A, a subpopulation of recycling endosomes redistributes to pericentriolar clusters, resulting in sequestration of melanosomal enzymes like Tyrp1 in vacuolar endosomes and consequent inhibition of melanin synthesis and melanosome maturation. Immunocytochemistry, live cell imaging, and electron tomography reveal AP-1- and KIF13A-dependent dynamic close appositions and continuities between peripheral endosomal tubules and melanosomes. Our results reveal that LRO protein sorting is coupled to cell type-specific positioning of endosomes that facilitate endosome-LRO contacts and are required for organelle maturation.
Collapse
Affiliation(s)
- Cédric Delevoye
- Structure and Membrane Compartments, Centre Nationale de la Recherche Scientifique, UMR 144 Institut Curie, Centre de Recherche, Paris F-75248, France
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
9
|
Tomova C, Humbel BM, Geerts WJC, Entzeroth R, Holthuis JCM, Verkleij AJ. Membrane Contact Sites between Apicoplast and ER inToxoplasma gondiiRevealed by Electron Tomography. Traffic 2009; 10:1471-80. [DOI: 10.1111/j.1600-0854.2009.00954.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
|
10
|
van Niftrik L, Geerts WJC, van Donselaar EG, Humbel BM, Webb RI, Harhangi HR, Camp HJMOD, Fuerst JA, Verkleij AJ, Jetten MSM, Strous M. Cell division ring, a new cell division protein and vertical inheritance of a bacterial organelle in anammox planctomycetes. Mol Microbiol 2009; 73:1009-19. [DOI: 10.1111/j.1365-2958.2009.06841.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
11
|
van Niftrik L, Geerts WJC, van Donselaar EG, Humbel BM, Yakushevska A, Verkleij AJ, Jetten MSM, Strous M. Combined structural and chemical analysis of the anammoxosome: A membrane-bounded intracytoplasmic compartment in anammox bacteria. J Struct Biol 2008; 161:401-10. [PMID: 17604181 DOI: 10.1016/j.jsb.2007.05.005] [Citation(s) in RCA: 118] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2007] [Revised: 05/18/2007] [Accepted: 05/20/2007] [Indexed: 10/23/2022]
Abstract
Anammox bacteria have unique intracellular membranes that divide their cytoplasm into three separate compartments. The largest and innermost cytoplasmic compartment, the anammoxosome, is hypothesized to be the locus of all catabolic reactions in the anammox metabolism. Electron tomography showed that the anammoxosome and its membrane were highly folded. This finding was confirmed by a transmission electron microscopy study using different sample preparation methods. Further, in this study electron-dense particles were observed and electron tomography showed that they were confined to the anammoxosome compartment. Energy dispersive X-ray analysis revealed that these particles contained iron. The functional significance of a highly folded anammoxosome membrane and intracellular iron storage particles are discussed in relation to their possible function in energy generation.
Collapse
Affiliation(s)
- Laura van Niftrik
- Department of Microbiology, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands
| | | | | | | | | | | | | | | |
Collapse
|
12
|
van Niftrik L, Geerts WJC, van Donselaar EG, Humbel BM, Webb RI, Fuerst JA, Verkleij AJ, Jetten MSM, Strous M. Linking ultrastructure and function in four genera of anaerobic ammonium-oxidizing bacteria: cell plan, glycogen storage, and localization of cytochrome C proteins. J Bacteriol 2008; 190:708-17. [PMID: 17993524 PMCID: PMC2223682 DOI: 10.1128/jb.01449-07] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2007] [Accepted: 10/31/2007] [Indexed: 11/20/2022] Open
Abstract
Anaerobic ammonium oxidation (anammox) is an ecologically and industrially important process and is performed by a clade of deeply branching Planctomycetes. Anammox bacteria possess an intracytoplasmic membrane-bounded organelle, the anammoxosome. In the present study, the ultrastructures of four different genera of anammox bacteria were compared with transmission electron microscopy and electron tomography. The four anammox genera shared a common cell plan and contained glycogen granules. Differences between the four genera included cell size (from 800 to 1,100 nm in diameter), presence or absence of cytoplasmic particles, and presence or absence of pilus-like appendages. Furthermore, cytochrome c proteins were detected exclusively inside the anammoxosome. This detection provides further support for the hypothesis that this organelle is the locus of anammox catabolism.
Collapse
Affiliation(s)
- Laura van Niftrik
- Department of Microbiology, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands
| | | | | | | | | | | | | | | | | |
Collapse
|
13
|
Mari M, Bujny MV, Zeuschner D, Geerts WJC, Griffith J, Petersen CM, Cullen PJ, Klumperman J, Geuze HJ. SNX1 defines an early endosomal recycling exit for sortilin and mannose 6-phosphate receptors. Traffic 2007; 9:380-93. [PMID: 18088323 DOI: 10.1111/j.1600-0854.2007.00686.x] [Citation(s) in RCA: 128] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Mannose-6-phosphate receptors (MPRs) transport lysosomal hydrolases from the trans Golgi network (TGN) to endosomes. Recently, the multi-ligand receptor sortilin has also been implicated in this transport, but the transport carriers involved herein have not been identified. By quantitative immuno-electron microscopy, we localized endogenous sortilin of HepG2 cells predominantly to the TGN and endosomes. In the TGN, sortilin colocalized with MPRs in the same clathrin-coated vesicles. In endosomes, sortilin and MPRs concentrated in sorting nexin 1 (SNX1)-positive buds and vesicles. SNX1 depletion by small interfering RNA resulted in decreased pools of sortilin in the TGN and an increase in lysosomal degradation. These data indicate that sortilin and MPRs recycle to the TGN in SNX1-dependent carriers, which we named endosome-to-TGN transport carriers (ETCs). Notably, ETCs emerge from early endosomes (EE), lack recycling plasma membrane proteins and by three-dimensional electron tomography exhibit unique structural features. Hence, ETCs are distinct from hitherto described EE-derived membranes involved in recycling. Our data emphasize an important role of EEs in recycling to the TGN and indicate that different, specialized exit events occur on the same EE vacuole.
Collapse
Affiliation(s)
- Muriel Mari
- Cell Microscopy Center, Department of Cell Biology, Institute of Biomembranes, University Medical Centre (UMC) Utrecht, AZU Rm G02.525, 3584 CX Utrecht, The Netherlands
| | | | | | | | | | | | | | | | | |
Collapse
|
14
|
Yakushevska AE, Lebbink MN, Geerts WJC, Spek L, van Donselaar EG, Jansen KA, Humbel BM, Post JA, Verkleij AJ, Koster AJ. STEM tomography in cell biology. J Struct Biol 2007; 159:381-91. [PMID: 17600727 DOI: 10.1016/j.jsb.2007.04.006] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2007] [Revised: 04/12/2007] [Accepted: 04/14/2007] [Indexed: 11/27/2022]
Abstract
Transmission electron tomography has been used in biological sciences for quite some time and proven to be a valuable tool. However, to date, the different Scanning Transmission modes are almost not used for electron tomography on resin-embedded biological material. We explored different STEM modes on epon-embedded, osmium-uranyl-lead-stained biological material. Bright Field-TEM and High Angle Annular Dark Field-STEM tomograms from the same areas were recorded and compared. Contrast and signal-to-noise ratios were calculated. Template matching was used to validate results obtained in Bright Field-TEM and High Angle Annular Dark Field-STEM tomograms. It is concluded that High Angle Annular Dark Field-STEM gives a five times better contrast and signal-to-noise ratio than Bright Field-TEM. Template matching showed that 1.3 times more information could be extracted from High Angle Annular Dark Field-STEM tomograms than from Bright Field-TEM tomograms.
Collapse
Affiliation(s)
- A E Yakushevska
- Cellular Architecture and Dynamics, Institute of Biomembranes, Faculty of Science, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | | | | | | | | | | | | | | | | | | |
Collapse
|
15
|
Lebbink MN, Geerts WJC, van der Krift TP, Bouwhuis M, Hertzberger LO, Verkleij AJ, Koster AJ. Template matching as a tool for annotation of tomograms of stained biological structures. J Struct Biol 2006; 158:327-35. [PMID: 17270464 DOI: 10.1016/j.jsb.2006.12.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2006] [Revised: 12/05/2006] [Accepted: 12/06/2006] [Indexed: 10/23/2022]
Abstract
In recent years, electron tomography has improved our three-dimensional (3D) insight in the structural architecture of cells and organelles. For studies that involve the 3D imaging of stained sections, manual annotation of tomographic data has been an important method to help understand the overall 3D morphology of cellular compartments. Here, we postulate that template matching can provide a tool for more objective annotation and contouring of cellular structures. Also, this technique can extract information hitherto unharvested in tomographic studies. To evaluate the performance of template matching on tomograms of stained sections, we generated several templates representing a piece of microtubule or patches of membranes of different staining-thicknesses. These templates were matched to tomograms of stained electron microscopy sections. Both microtubules and ER-Golgi membranes could be detected using this method. By matching cuboids of different thicknesses, we were able to distinguish between coated and non-coated endosomal membrane-domains. Finally, heterogeneity in staining-thickness of endosomes could be observed. Template matching can be a useful addition to existing annotation-methods, and provide additional insights in cellular architecture.
Collapse
Affiliation(s)
- Misjaël N Lebbink
- Cellular Architecture and Dynamics, Utrecht University, The Netherlands.
| | | | | | | | | | | | | |
Collapse
|
16
|
Tomova C, Geerts WJC, Müller-Reichert T, Entzeroth R, Humbel BM. New comprehension of the apicoplast of Sarcocystis by transmission electron tomography. Biol Cell 2006; 98:535-45. [PMID: 16706752 DOI: 10.1042/bc20060028] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND INFORMATION Apicomplexan parasites (like Plasmodium, Toxoplasma, Eimeria and Sarcocystis) contain a distinctive organelle, the apicoplast, acquired by a secondary endosymbiotic process analogous to chloroplasts and mitochondria. The apicoplast is essential for long-term survival of the parasite. This prokaryotic origin implies that molecular and metabolic processes in the apicoplast differ from those of the eukaryotic host cells and therefore offer options for specific chemotherapeutic treatment. We studied the apicoplast in high-pressure frozen and freeze-substituted cysts of Sarcocystis sp. from roe deer (Capreolus capreolus) to get better insight in apicoplast morphology. RESULTS AND CONCLUSIONS We observed that the apicoplast contains four continuous membranes. The two inner membranes have a circular shape with a constant distance from each other and large-sized protein complexes are located between them. The two outer membranes have irregular shapes. The periplastid membrane also contains large-sized protein complexes, while the outer membrane displays protuberances into the parasite cytoplasm. In addition, it is closely associated with the endoplasmic reticulum by 'contact sites'.
Collapse
Affiliation(s)
- Cveta Tomova
- Institut für Zoologie/Spezielle Zoologie, Technische Universität Dresden, Helmholtzstrasse 10, D-01062 Dresden, Germany
| | | | | | | | | |
Collapse
|
17
|
Rodriguez D, Bárcena M, Möbius W, Schleich S, Esteban M, Geerts WJC, Koster AJ, Griffiths G, Locker JK. A vaccinia virus lacking A10L: viral core proteins accumulate on structures derived from the endoplasmic reticulum. Cell Microbiol 2006; 8:427-37. [PMID: 16469055 DOI: 10.1111/j.1462-5822.2005.00632.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The assembly of the intracellular mature virus (IMV) of vaccinia virus (VV), the prototype member of the poxviridae, is poorly understood and controversial. We have previously proposed that the IMV is composed of a continuous double-membraned cisterna derived from the smooth ER, whereby the genome-containing core is enwrapped by a part of this cisterna. In the present study we characterize a mutant virus in which the synthesis of the major core protein A10L can be conditionally expressed. Without A10L, IMVs are not made; immature viruses (IVs) and regularly stacked membrane structures that contain viral DNA, accumulate instead. By immunolabelling of thawed cryo-sections these stacks contain most of the viral core proteins and low levels of viral membrane proteins. Importantly, the stacked membranes could be labelled with antibodies to an ER marker protein, implying that they are derived from this cellular compartment. By electron tomography (ET) on semi-thin cryo-sections we show that the membranes of the stacks are continuous with the membranes of the IVs. Direct continuities with ER cisternae, to which the stacks are tightly apposed, were, however, not unequivocally seen. Finally, ET revealed how the IV membranes separated to become two-membrane profiles. Taken together, this study shows that VV core proteins and the viral DNA can coassemble onto ER-derived membranes that are continuous with the membranes of the IVs.
Collapse
Affiliation(s)
- Dolores Rodriguez
- Centro Nacional de Biotecnología, Campus Universidad Autónoma, 28049 Madrid, Spain
| | | | | | | | | | | | | | | | | |
Collapse
|
18
|
Zeuschner D, Geerts WJC, van Donselaar E, Humbel BM, Slot JW, Koster AJ, Klumperman J. Immuno-electron tomography of ER exit sites reveals the existence of free COPII-coated transport carriers. Nat Cell Biol 2006; 8:377-83. [PMID: 16531996 DOI: 10.1038/ncb1371] [Citation(s) in RCA: 143] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2005] [Accepted: 01/05/2006] [Indexed: 01/16/2023]
Abstract
Transport from the endoplasmic reticulum (ER) to the Golgi complex requires assembly of the COPII coat complex at ER exit sites. Recent studies have raised the question as to whether in mammalian cells COPII coats give rise to COPII-coated transport vesicles or instead form ER sub-domains that collect proteins for transport via non-coated carriers. To establish whether COPII-coated vesicles do exist in vivo, we developed approaches to combine quantitative immunogold labelling (to identify COPII) and three-dimensional electron tomography (to reconstruct entire membrane structures). In tomograms of both chemically fixed and high-pressure-frozen HepG2 cells, immuno-labelled COPII was found on ER-associated buds as well as on free approximately 50-nm diameter vesicles. In addition, we identified a novel type of COPII-coated structure that consists of partially COPII-coated, 150-200-nm long, dumb-bell-shaped tubules. Both COPII-coated carriers also contain the SNARE protein Sec22b, which is necessary for downstream fusion events. Our studies unambiguously establish the existence of free, bona fide COPII-coated transport carriers at the ER-Golgi interface, suggesting that assembly of COPII coats in vivo can result in vesicle formation.
Collapse
Affiliation(s)
- Dagmar Zeuschner
- Department of Cell Biology, Institute of Biomembranes, UMC Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
| | | | | | | | | | | | | |
Collapse
|
19
|
Grabenbauer M, Geerts WJC, Fernadez-Rodriguez J, Hoenger A, Koster AJ, Nilsson T. Correlative microscopy and electron tomography of GFP through photooxidation. Nat Methods 2005; 2:857-62. [PMID: 16278657 DOI: 10.1038/nmeth806] [Citation(s) in RCA: 186] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2005] [Accepted: 09/24/2005] [Indexed: 02/06/2023]
Abstract
We have developed a simple correlative photooxidation method that allows for the direct ultrastructural visualization of the green fluorescent protein (GFP) upon illumination. The method, termed GRAB for GFP recognition after bleaching, uses oxygen radicals generated during the GFP bleaching process to photooxidize 3,3'-diaminobenzidine (DAB) into an electron-dense precipitate that can be visualized by routine electron microscopy and electron tomography. The amount of DAB product produced by the GRAB method appears to be linear with the initial fluorescence, and the resulting images are of sufficient quality to reveal detailed spatial information. This is exemplified by the observed intra-Golgi stack and intracisternal distribution of a human Golgi resident glycosylation enzyme, N-acetylgalactosaminyltransferase-2 fused either to enhanced GFP or CFP.
Collapse
Affiliation(s)
- Markus Grabenbauer
- Cell Biology and Cell Biophysics Program, EMBL, Meyerhofstr. 1, D-69117 Heidelberg, Germany
| | | | | | | | | | | |
Collapse
|
20
|
Murk JLAN, Lebbink MN, Humbel BM, Geerts WJC, Griffith JM, Langenberg DML, Verreck FAW, Verkleij AJ, Koster AJ, Geuze HJ, Kleijmeer MJ. 3-D Structure of multilaminar lysosomes in antigen presenting cells reveals trapping of MHC II on the internal membranes. Traffic 2005; 5:936-45. [PMID: 15522096 DOI: 10.1111/j.1600-0854.2004.00235.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In late endosomes and lysosomes of antigen presenting cells major histocompatibility complex class II (MHC II) molecules bind peptides from degraded internalized pathogens. These compartments are called MHC class II compartments (MIICs), and from here peptide-loaded MHC II is transported to the cell surface for presentation to helper T-lymphocytes to generate an immune response. Recent studies from our group in mouse dendritic cells indicate that the MHC class II on internal vesicles of multivesicular late endosomes or multivesicular bodies is the main source of MHC II at the plasma membrane. We showed that dendritic cell activation triggers a back fusion mechanism whereby MHC II from the inner membranes is delivered to the multivesicular bodies' outer membrane. Another type of MIIC in B-lymphocytes and dendritic cells is more related to lysosomes and often appears as a multilaminar organelle with abundant MHC II-enriched internal membrane sheets. These multilaminar lysosomes have a functioning peptide-loading machinery, but to date it is not clear whether peptide-loaded MHC II molecules from the internal membranes can make their way to the cell surface and contribute to T cell activation. To obtain detailed information on the membrane organization of multilaminar lysosomes and investigate possible escape routes from the lumen of this organelle, we performed electron tomography on cryo-immobilized B-lymphocytes and dendritic cells. Our high-resolution 3-D reconstructions of multilaminar lysosomes indicate that their membranes are organized in such a way that MHC class II may be trapped on the inner membranes, without the possibility to escape to the cell surface.
Collapse
Affiliation(s)
- Jean-Luc A N Murk
- Department of Cell Biology, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX, Utrecht, the Netherlands
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
21
|
Trucco A, Polishchuk RS, Martella O, Di Pentima A, Fusella A, Di Giandomenico D, San Pietro E, Beznoussenko GV, Polishchuk EV, Baldassarre M, Buccione R, Geerts WJC, Koster AJ, Burger KNJ, Mironov AA, Luini A. Secretory traffic triggers the formation of tubular continuities across Golgi sub-compartments. Nat Cell Biol 2004; 6:1071-81. [PMID: 15502824 DOI: 10.1038/ncb1180] [Citation(s) in RCA: 415] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The organization of secretory traffic remains unclear, mainly because of the complex structure and dynamics of the secretory pathway. We have thus studied a simplified system, a single synchronized traffic wave crossing an individual Golgi stack, using electron tomography. Endoplasmic-reticulum-to-Golgi carriers join the stack by fusing with cis cisternae and induce the formation of intercisternal tubules, through which they redistribute their contents throughout the stack. These tubules seem to be pervious to Golgi enzymes, whereas Golgi vesicles are depleted of both enzymes and cargo. Cargo then traverses the stack without leaving the cisternal lumen. When cargo exits the stack, intercisternal connections disappear. These findings provide a new view of secretory traffic that includes dynamic intercompartment continuities as key players.
Collapse
Affiliation(s)
- Alvar Trucco
- Department of Cell Biology and Oncology, Consorzio Mario Negri Sud, 66030 Santa Maria Imbaro, Chieti, Italy
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
22
|
Kweon HS, Beznoussenko GV, Micaroni M, Polishchuk RS, Trucco A, Martella O, Di Giandomenico D, Marra P, Fusella A, Di Pentima A, Berger EG, Geerts WJC, Koster AJ, Burger KNJ, Luini A, Mironov AA. Golgi enzymes are enriched in perforated zones of golgi cisternae but are depleted in COPI vesicles. Mol Biol Cell 2004; 15:4710-24. [PMID: 15282336 PMCID: PMC519161 DOI: 10.1091/mbc.e03-12-0881] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
In the most widely accepted version of the cisternal maturation/progression model of intra-Golgi transport, the polarity of the Golgi complex is maintained by retrograde transport of Golgi enzymes in COPI-coated vesicles. By analyzing enzyme localization in relation to the three-dimensional ultrastructure of the Golgi complex, we now observe that Golgi enzymes are depleted in COPI-coated buds and 50- to 60-nm COPI-dependent vesicles in a variety of different cell types. Instead, we find that Golgi enzymes are concentrated in the perforated zones of cisternal rims both in vivo and in a cell-free system. This lateral segregation of Golgi enzymes is detectable in some stacks during steady-state transport, but it was significantly prominent after blocking endoplasmic reticulum-to-Golgi transport. Delivery of transport carriers to the Golgi after the release of a transport block leads to a diminution in Golgi enzyme concentrations in perforated zones of cisternae. The exclusion of Golgi enzymes from COPI vesicles and their transport-dependent accumulation in perforated zones argues against the current vesicle-mediated version of the cisternal maturation/progression model.
Collapse
Affiliation(s)
- Hee-Seok Kweon
- Department of Cell Biology and Oncology, Consorzio Mario Negri Sud, 66030 Santa Maria Imbaro (Chieti), Italy
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
23
|
Mironov AA, Mironov AA, Beznoussenko GV, Trucco A, Lupetti P, Smith JD, Geerts WJC, Koster AJ, Burger KNJ, Martone ME, Deerinck TJ, Ellisman MH, Luini A. ER-to-Golgi carriers arise through direct en bloc protrusion and multistage maturation of specialized ER exit domains. Dev Cell 2003; 5:583-94. [PMID: 14536060 DOI: 10.1016/s1534-5807(03)00294-6] [Citation(s) in RCA: 196] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Protein transport between the ER and the Golgi in mammalian cells occurs via large pleiomorphic carriers, and most current models suggest that these are formed by the fusion of small ER-derived COPII vesicles. We have examined the dynamics and structural features of these carriers during and after their formation from the ER by correlative video/light electron microscopy and tomography. We found that saccular carriers containing either the large supramolecular cargo procollagen or the small diffusible cargo protein VSVG arise through cargo concentration and direct en bloc protrusion of specialized ER domains in the vicinity of COPII-coated exit sites. This formation process is COPII dependent but does not involve budding and fusion of COPII-dependent vesicles. Fully protruded saccules then move centripetally, evolving into one of two types of carriers (with distinct kinetic and structural features). These findings provide an alternative framework for analysis of ER-to-Golgi traffic.
Collapse
Affiliation(s)
- Alexander A Mironov
- Department of Cell Biology and Oncology, Istituto di Ricerche Farmacologiche Mario Negri, Consorzio Mario Negri Sud, 66030 Santa Maria Imbaro, (Chieti), Italy
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
24
|
Abstract
Transmission electron microscopy images acquired under tilted-beam conditions experience an image shift as a function of defocus settings - a fact that is exploited as a method for defocus determination in most of the automated tomography data collection systems. Although the method was shown to be highly accurate for a large variety of specimens, we point out that in its original design it can strictly only be applied to images of untilted samples. The application to tilted samples and thus in automated electron tomography is impaired mainly due to a defocus change across the images, resulting in reduced accuracy. In this communication we present a method that can be used to improve the accuracy of the basic autofocusing procedures currently used in systems for automated electron tomography.
Collapse
Affiliation(s)
- U Ziese
- Molecular Cell Biology, Utrecht University, 3584 CH Utrecht, The Netherlands
| | | | | | | | | |
Collapse
|
25
|
Ziese U, Janssen AH, Murk JL, Geerts WJC, Van der Krift T, Verkleij AJ, Koster AJ. Automated high-throughput electron tomography by pre-calibration of image shifts. J Microsc 2002; 205:187-200. [PMID: 11879433 DOI: 10.1046/j.0022-2720.2001.00987.x] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Electron tomography is a versatile method for obtaining three-dimensional (3D) images with transmission electron microscopy. The technique is suitable to investigate cell organelles and tissue sections (100-500 nm thick) with 4-20 nm resolution. 3D reconstructions are obtained by processing a series of images acquired with the samples tilted over different angles. While tilting the sample, image shifts and defocus changes of several microm can occur. The current generation of automated acquisition software detects and corrects for these changes with a procedure that incorporates switching the electron optical magnification. We developed a novel method for data collection based on the measurement of shifts prior to data acquisition, which results in a five-fold increase in speed, enabling the acquisition of 151 images in less than 20 min. The method will enhance the quality of a tilt series by minimizing the amount of required focus-change compensation by aligning the optical axis to the tilt axis of the specimen stage. The alignment is achieved by invoking an amount of image shift as deduced from the mathematical model describing the effect of specimen tilt. As examples for application in biological and materials sciences 3D reconstructions of a mitochondrion and a zeolite crystal are presented.
Collapse
Affiliation(s)
- U Ziese
- Molecular Cell Biology, Utrecht University, 3584 CH Utrecht, The Netherlands
| | | | | | | | | | | | | |
Collapse
|