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VAN Donselaar EG, Dorresteijn B, Popov-Čeleketić D, VAN DE Wetering WJ, Verrips TC, Boekhout T, Schneijdenberg CTWM, Xenaki AT, VAN DER Krift TP, Müller WH. Extremely thin layer plastification for focused-ion beam scanning electron microscopy: an improved method to study cell surfaces and organelles of cultured cells. J Microsc 2018; 270:359-373. [PMID: 29574724 DOI: 10.1111/jmi.12694] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Revised: 02/16/2018] [Accepted: 02/17/2018] [Indexed: 02/01/2023]
Abstract
Since the recent boost in the usage of electron microscopy in life-science research, there is a great need for new methods. Recently minimal resin embedding methods have been successfully introduced in the sample preparation for focused-ion beam scanning electron microscopy (FIB-SEM). In these methods several possibilities are given to remove as much resin as possible from the surface of cultured cells or multicellular organisms. Here we introduce an alternative way in the minimal resin embedding method to remove excess of resin from two widely different cell types by the use of Mascotte filter paper. Our goal in correlative light and electron microscopic studies of immunogold-labelled breast cancer SKBR3 cells was to visualise gold-labelled HER2 plasma membrane proteins as well as the intracellular structures of flat and round cells. We found a significant difference (p < 0.001) in the number of gold particles of selected cells per 0.6 μm2 cell surface: on average a flat cell contained 2.46 ± 1.98 gold particles, and a round cell 5.66 ± 2.92 gold particles. Moreover, there was a clear difference in the subcellular organisation of these two cells. The round SKBR3 cell contained many organelles, such as mitochondria, Golgi and endoplasmic reticulum, when compared with flat SKBR3 cells. Our next goal was to visualise crosswall associated organelles, septal pore caps, of Rhizoctonia solani fungal cells by the combined use of a heavy metal staining and our extremely thin layer plastification (ETLP) method. At low magnifications this resulted into easily finding septa which appeared as bright crosswalls in the back-scattered electron mode in the scanning electron microscope. Then, a septum was selected for FIB-SEM. Cross-sectioned views clearly revealed the perforate septal pore cap of R. solani next to other structures, such as mitochondria, endoplasmic reticulum, lipid bodies, dolipore septum, and the pore channel. As the ETLP method was applied on two widely different cell types, the use of the ETLP method will be beneficial to correlative studies of other cell model systems and multicellular organisms.
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Affiliation(s)
- E G VAN Donselaar
- Department of Cell Biology, University Medical Center Utrecht (UMCU), Utrecht, the Netherlands
| | - B Dorresteijn
- Science Faculty, Biology Department, Utrecht University, Utrecht, the Netherlands
| | - D Popov-Čeleketić
- Science Faculty, Biology Department, Utrecht University, Utrecht, the Netherlands.,Visuals Consulting, Utrecht, the Netherlands
| | - W J VAN DE Wetering
- Science Faculty, Biology Department, Utrecht University, Utrecht, the Netherlands.,QVQ, Utrecht, the Netherlands
| | | | - T Boekhout
- Westerdijk Fungal Biodiversity Institute, Utrecht Science Park, Utrecht, the Netherlands.,Institute of Biodiversity and Ecosystem Dynamics (IBED), University of Amsterdam, Amsterdam, the Netherlands
| | | | - A T Xenaki
- Science Faculty, Biology Department, Utrecht University, Utrecht, the Netherlands
| | - T P VAN DER Krift
- Science Faculty, Chemistry Department, Utrecht University, Utrecht, the Netherlands
| | - W H Müller
- Science Faculty, Chemistry Department, Utrecht University, Utrecht, the Netherlands
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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.
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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.
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Popov-Čeleketić D, Bianchi F, Ruiz SJ, Meutiawati F, Poolman B. A Plasma Membrane Association Module in Yeast Amino Acid Transporters. J Biol Chem 2016; 291:16024-37. [PMID: 27226538 DOI: 10.1074/jbc.m115.706770] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [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: 11/25/2015] [Indexed: 12/22/2022] Open
Abstract
Amino acid permeases (AAPs) in the plasma membrane (PM) of Saccharomyces cerevisiae are responsible for the uptake of amino acids and involved in regulation of their cellular levels. Here, we report on a strong and complex module for PM association found in the C-terminal tail of AAPs. Using in silico analyses and mutational studies we found that the C-terminal sequences of Gap1, Bap2, Hip1, Tat1, Tat2, Mmp1, Sam3, Agp1, and Gnp1 are about 50 residues long, associate with the PM, and have features that discriminate them from the termini of organellar amino acid transporters. We show that this sequence (named PMasseq) contains an amphipathic α-helix and the FWC signature, which is palmitoylated by palmitoyltransferase Pfa4. Variations of PMasseq, found in different AAPs, lead to different mobilities and localization patterns, whereas the disruption of the sequence has an adverse effect on cell viability. We propose that PMasseq modulates the function and localization of AAPs along the PM. PMasseq is one of the most complex protein signals for plasma membrane association across species and can be used as a delivery vehicle for the PM.
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Affiliation(s)
- Dušan Popov-Čeleketić
- From the Department of Biochemistry, University of Groningen, Groningen Biomolecular Sciences and Biotechnology Institute, and Zernike Institute for Advanced Materials, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Frans Bianchi
- From the Department of Biochemistry, University of Groningen, Groningen Biomolecular Sciences and Biotechnology Institute, and Zernike Institute for Advanced Materials, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Stephanie J Ruiz
- From the Department of Biochemistry, University of Groningen, Groningen Biomolecular Sciences and Biotechnology Institute, and Zernike Institute for Advanced Materials, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Febrina Meutiawati
- From the Department of Biochemistry, University of Groningen, Groningen Biomolecular Sciences and Biotechnology Institute, and Zernike Institute for Advanced Materials, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Bert Poolman
- From the Department of Biochemistry, University of Groningen, Groningen Biomolecular Sciences and Biotechnology Institute, and Zernike Institute for Advanced Materials, Nijenborgh 4, 9747 AG Groningen, The Netherlands
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Popov-Čeleketić D, van Bergen En Henegouwen PMP. Membrane domain formation-a key factor for targeted intracellular drug delivery. Front Physiol 2014; 5:462. [PMID: 25520666 PMCID: PMC4251288 DOI: 10.3389/fphys.2014.00462] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [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: 09/16/2014] [Accepted: 11/11/2014] [Indexed: 01/23/2023] Open
Abstract
Protein molecules, toxins and viruses internalize into the cell via receptor-mediated endocytosis (RME) using specific proteins and lipids in the plasma membrane. The plasma membrane is a barrier for many pharmaceutical agents to enter into the cytoplasm of target cells. In the case of cancer cells, tissue-specific biomarkers in the plasma membrane, like cancer-specific growth factor receptors, could be excellent candidates for RME-dependent drug delivery. Recent data suggest that agent binding to these receptors at the cell surface, resulting in membrane domain formation by receptor clustering, can be used for the initiation of RME. As a result, these pharmaceutical agents are internalized into the cells and follow different routes until they reach their final intracellular targets like lysosomes or Golgi. We propose that clustering induced formation of plasma membrane microdomains enriched in receptors, sphingolipids, and inositol lipids, leads to membrane bending which functions as the onset of RME. In this review we will focus on the role of domain formation in RME and discuss potential applications for targeted intracellular drug delivery.
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Affiliation(s)
- Dušan Popov-Čeleketić
- Division of Cell Biology, Department of Biology, Faculty of Science, Utrecht University Utrecht, Netherlands
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Waegemann K, Popov-Čeleketić D, Neupert W, Azem A, Mokranjac D. Cooperation of TOM and TIM23 complexes during translocation of proteins into mitochondria. J Mol Biol 2014; 427:1075-84. [PMID: 25083920 DOI: 10.1016/j.jmb.2014.07.015] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Revised: 07/14/2014] [Accepted: 07/22/2014] [Indexed: 01/07/2023]
Abstract
Translocation of the majority of mitochondrial proteins from the cytosol into mitochondria requires the cooperation of TOM and TIM23 complexes in the outer and inner mitochondrial membranes. The molecular mechanisms underlying this cooperation remain largely unknown. Here, we present biochemical and genetic evidence that at least two contacts from the side of the TIM23 complex play an important role in TOM-TIM23 cooperation in vivo. Tim50, likely through its very C-terminal segment, interacts with Tom22. This interaction is stimulated by translocating proteins and is independent of any other TOM-TIM23 contact known so far. Furthermore, the exposure of Tim23 on the mitochondrial surface depends not only on its interaction with Tim50 but also on the dynamics of the TOM complex. Destabilization of the individual contacts reduces the efficiency of import of proteins into mitochondria and destabilization of both contacts simultaneously is not tolerated by yeast cells. We conclude that an intricate and coordinated network of protein-protein interactions involving primarily Tim50 and also Tim23 is required for efficient translocation of proteins across both mitochondrial membranes.
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Affiliation(s)
- Karin Waegemann
- Department of Physiological Chemistry, Medical Faculty, University of Munich, Butenandtstrasse 5, 81377 Munich, Germany
| | - Dušan Popov-Čeleketić
- Department of Physiological Chemistry, Medical Faculty, University of Munich, Butenandtstrasse 5, 81377 Munich, Germany
| | - Walter Neupert
- Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Abdussalam Azem
- Department of Biochemistry and Molecular Biology, George S. Wise Faculty of Life Sciences, Tel Aviv University, 69978 Tel Aviv, Israel
| | - Dejana Mokranjac
- Department of Physiological Chemistry, Medical Faculty, University of Munich, Butenandtstrasse 5, 81377 Munich, Germany.
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Gevorkyan-Airapetov L, Zohary K, Popov-Čeleketić D, Mapa K, Hell K, Neupert W, Azem A, Mokranjac D. Interaction of Tim23 with Tim50 Is Essential for Protein Translocation by the Mitochondrial TIM23 Complex. J Biol Chem 2009; 284:4865-72. [DOI: 10.1074/jbc.m807041200] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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