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Diep DTV, Collado J, Hugenroth M, Fausten RM, Percifull L, Wälte M, Schuberth C, Schmidt O, Fernández-Busnadiego R, Bohnert M. A metabolically controlled contact site between vacuoles and lipid droplets in yeast. Dev Cell 2024; 59:740-758.e10. [PMID: 38367622 DOI: 10.1016/j.devcel.2024.01.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 11/17/2023] [Accepted: 01/18/2024] [Indexed: 02/19/2024]
Abstract
The lipid droplet (LD) organization proteins Ldo16 and Ldo45 affect multiple aspects of LD biology in yeast. They are linked to the LD biogenesis machinery seipin, and their loss causes defects in LD positioning, protein targeting, and breakdown. However, their molecular roles remained enigmatic. Here, we report that Ldo16/45 form a tether complex with Vac8 to create vacuole lipid droplet (vCLIP) contact sites, which can form in the absence of seipin. The phosphatidylinositol transfer protein (PITP) Pdr16 is a further vCLIP-resident recruited specifically by Ldo45. While only an LD subpopulation is engaged in vCLIPs at glucose-replete conditions, nutrient deprivation results in vCLIP expansion, and vCLIP defects impair lipophagy upon prolonged starvation. In summary, Ldo16/45 are multifunctional proteins that control the formation of a metabolically regulated contact site. Our studies suggest a link between LD biogenesis and breakdown and contribute to a deeper understanding of how lipid homeostasis is maintained during metabolic challenges.
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Affiliation(s)
- Duy Trong Vien Diep
- Institute of Cell Dynamics and Imaging, University of Münster, Von-Esmarch-Strasse 56, 48149 Münster, Germany; Cells in Motion Interfaculty Centre (CiM), University of Münster, Münster, Germany
| | - Javier Collado
- Institute of Neuropathology, University Medical Center Göttingen, 37099 Göttingen, Germany
| | - Marie Hugenroth
- Institute of Cell Dynamics and Imaging, University of Münster, Von-Esmarch-Strasse 56, 48149 Münster, Germany; Cells in Motion Interfaculty Centre (CiM), University of Münster, Münster, Germany
| | - Rebecca Martina Fausten
- Institute of Cell Dynamics and Imaging, University of Münster, Von-Esmarch-Strasse 56, 48149 Münster, Germany; Cells in Motion Interfaculty Centre (CiM), University of Münster, Münster, Germany
| | - Louis Percifull
- Institute of Cell Dynamics and Imaging, University of Münster, Von-Esmarch-Strasse 56, 48149 Münster, Germany; Cells in Motion Interfaculty Centre (CiM), University of Münster, Münster, Germany
| | - Mike Wälte
- Institute of Cell Dynamics and Imaging, University of Münster, Von-Esmarch-Strasse 56, 48149 Münster, Germany
| | - Christian Schuberth
- Institute of Cell Dynamics and Imaging, University of Münster, Von-Esmarch-Strasse 56, 48149 Münster, Germany; Cells in Motion Interfaculty Centre (CiM), University of Münster, Münster, Germany
| | - Oliver Schmidt
- Institute of Cell Biology, Biocenter Innsbruck, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Rubén Fernández-Busnadiego
- Institute of Neuropathology, University Medical Center Göttingen, 37099 Göttingen, Germany; Cluster of Excellence "Multiscale Imaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany; Faculty of Physics, University of Göttingen, Göttingen 37077, Germany
| | - Maria Bohnert
- Institute of Cell Dynamics and Imaging, University of Münster, Von-Esmarch-Strasse 56, 48149 Münster, Germany; Cells in Motion Interfaculty Centre (CiM), University of Münster, Münster, Germany.
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2
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Eising S, Esch B, Wälte M, Vargas Duarte P, Walter S, Ungermann C, Bohnert M, Fröhlich F. A lysosomal biogenesis map reveals the cargo spectrum of yeast vacuolar protein targeting pathways. J Cell Biol 2022; 221:213011. [PMID: 35175277 PMCID: PMC8859911 DOI: 10.1083/jcb.202107148] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 12/20/2021] [Accepted: 01/18/2022] [Indexed: 12/15/2022] Open
Abstract
The lysosome is the major catabolic organelle in the cell that has been established as a key metabolic signaling center. Mutations in many lysosomal proteins have catastrophic effects and cause neurodegeneration, cancer, and age-related diseases. The vacuole is the lysosomal analog of Saccharomyces cerevisiae that harbors many evolutionary conserved proteins. Proteins reach vacuoles via the Vps10-dependent endosomal vacuolar protein sorting pathway, via the alkaline phosphatase (ALP or AP-3) pathway, and via the cytosol-to-vacuole transport (CVT) pathway. A systematic understanding of the cargo spectrum of each pathway is completely lacking. Here, we use quantitative proteomics of purified vacuoles to generate the yeast lysosomal biogenesis map. This dataset harbors information on the cargo-receptor relationship of almost all vacuolar proteins. We map binding motifs of Vps10 and the AP-3 complex and identify a novel cargo of the CVT pathway under nutrient-rich conditions. Our data show how organelle purification and quantitative proteomics can uncover fundamental insights into organelle biogenesis.
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Affiliation(s)
- Sebastian Eising
- Molecular Membrane Biology Group, Department of Biology/Chemistry, Osnabrück University, Osnabrück, Germany
| | - Bianca Esch
- Molecular Membrane Biology Group, Department of Biology/Chemistry, Osnabrück University, Osnabrück, Germany
| | - Mike Wälte
- Institute of Cell Dynamics and Imaging, University of Münster, Münster, Germany
| | - Prado Vargas Duarte
- Biochemistry Section, Department of Biology/Chemistry, Osnabrück University, Osnabrück, Germany
| | - Stefan Walter
- Center of Cellular Nanoanalytics Osnabrück, Osnabrück University, Osnabrück, Germany
| | - Christian Ungermann
- Biochemistry Section, Department of Biology/Chemistry, Osnabrück University, Osnabrück, Germany.,Center of Cellular Nanoanalytics Osnabrück, Osnabrück University, Osnabrück, Germany
| | - Maria Bohnert
- Institute of Cell Dynamics and Imaging, University of Münster, Münster, Germany.,Cells in Motion Interfaculty Centre, University of Münster, Münster, Germany
| | - Florian Fröhlich
- Molecular Membrane Biology Group, Department of Biology/Chemistry, Osnabrück University, Osnabrück, Germany.,Biochemistry Section, Department of Biology/Chemistry, Osnabrück University, Osnabrück, Germany
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3
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Lindemann O, Rossaint J, Najder K, Schimmelpfennig S, Hofschröer V, Wälte M, Fels B, Oberleithner H, Zarbock A, Schwab A. Intravascular adhesion and recruitment of neutrophils in response to CXCL1 depends on their TRPC6 channels. J Mol Med (Berl) 2020; 98:349-360. [PMID: 31950205 PMCID: PMC7080674 DOI: 10.1007/s00109-020-01872-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [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: 06/03/2019] [Revised: 12/21/2019] [Accepted: 01/03/2020] [Indexed: 02/07/2023]
Abstract
Abstract Here we report a novel role for TRPC6, a member of the transient receptor potential (TRPC) channel family, in the CXCL1-dependent recruitment of murine neutrophil granulocytes. Representing a central element of the innate immune system, neutrophils are recruited from the blood stream to a site of inflammation. The recruitment process follows a well-defined sequence of events including adhesion to the blood vessel walls, migration, and chemotaxis to reach the inflammatory focus. A common feature of the underlying signaling pathways is the utilization of Ca2+ ions as intracellular second messengers. However, the required Ca2+ influx channels are not yet fully characterized. We used WT and TRPC6−/− neutrophils for in vitro and TRPC6−/− chimeric mice (WT mice with WT or TRPC6−/− bone marrow cells) for in vivo studies. After renal ischemia and reperfusion injury, TRPC6−/− chimeric mice had an attenuated TRPC6−/− neutrophil recruitment and a better outcome as judged from the reduced increase in the plasma creatinine concentration. In the cremaster model CXCL1-induced neutrophil adhesion, arrest and transmigration were also decreased in chimeric mice with TRPC6−/− neutrophils. Using atomic force microscopy and microfluidics, we could attribute the recruitment defect of TRPC6−/− neutrophils to the impact of the channel on adhesion to endothelial cells. Mechanistically, TRPC6−/− neutrophils exhibited lower Ca2+ transients during the initial adhesion leading to diminished Rap1 and β2 integrin activation and thereby reduced ICAM-1 binding. In summary, our study reveals that TRPC6 channels in neutrophils are crucial signaling modules in their recruitment from the blood stream in response to CXCL1. Key point Neutrophil TRPC6 channels are crucial for CXCL1-triggered activation of integrins during the initial steps of neutrophil recruitment.
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Affiliation(s)
- Otto Lindemann
- Institute of Physiology II, Westfälische Wilhelms-Universität, Münster, Germany
| | - Jan Rossaint
- Department of Anaesthesiology, Intensive Care and Pain Medicine, University Hospital Münster, Münster, Germany
| | - Karolina Najder
- Institute of Physiology II, Westfälische Wilhelms-Universität, Münster, Germany
| | | | - Verena Hofschröer
- Institute of Physiology II, Westfälische Wilhelms-Universität, Münster, Germany
| | - Mike Wälte
- Institute of Physiology II, Westfälische Wilhelms-Universität, Münster, Germany.,Institute of Cell Dynamics and Imaging, Westfälische Wilhelms-Universität, Münster, Germany
| | - Benedikt Fels
- Institute of Physiology II, Westfälische Wilhelms-Universität, Münster, Germany
| | - Hans Oberleithner
- Institute of Physiology II, Westfälische Wilhelms-Universität, Münster, Germany
| | - Alexander Zarbock
- Department of Anaesthesiology, Intensive Care and Pain Medicine, University Hospital Münster, Münster, Germany
| | - Albrecht Schwab
- Institute of Physiology II, Westfälische Wilhelms-Universität, Münster, Germany.
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4
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Zuttion F, Ligeour C, Vidal O, Wälte M, Morvan F, Vidal S, Vasseur JJ, Chevolot Y, Phaner-Goutorbe M, Schillers H. The anti-adhesive effect of glycoclusters on Pseudomonas aeruginosa bacteria adhesion to epithelial cells studied by AFM single cell force spectroscopy. Nanoscale 2018; 10:12771-12778. [PMID: 29946584 DOI: 10.1039/c8nr03285h] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The human opportunistic pathogen Pseudomonas aeruginosa (PA) is responsible for chronic infections of the respiratory epithelium in cystic fibrosis patients. PA takes advantage of an arsenal of virulence factors to infect and colonize human lungs. Among them, the lectin LecA favours epithelium invasion by interacting with host cell globotriaosylceramide (Gb3). A new therapeutic approach is based on the development of synthetic multivalent molecules (glycoclusters) targeting LecA with a higher affinity than its natural ligand. Atomic force microscopy-single cell force spectroscopy has been used to study the effect of glycoclusters on the bacteria-cell interaction. Glycoclusters have been shown to affect the detachment work and detachment force of the bacteria-cell interaction. The specificity and the efficiency of the glycocluster in targeting the lectin and destabilizing the PA-epithelial cell adhesion are demonstrated and discussed.
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Affiliation(s)
- Francesca Zuttion
- Université de Lyon, Ecole Centrale de Lyon, Institut des Nanotechnologies de Lyon INL UMR-5270, CNRS, 36 avenue Guy de Collongue, 69134 Ecully, France.
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5
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Wales P, Schuberth CE, Aufschnaiter R, Fels J, García-Aguilar I, Janning A, Dlugos CP, Schäfer-Herte M, Klingner C, Wälte M, Kuhlmann J, Menis E, Hockaday Kang L, Maier KC, Hou W, Russo A, Higgs HN, Pavenstädt H, Vogl T, Roth J, Qualmann B, Kessels MM, Martin DE, Mulder B, Wedlich-Söldner R. Calcium-mediated actin reset (CaAR) mediates acute cell adaptations. eLife 2016; 5. [PMID: 27919320 PMCID: PMC5140269 DOI: 10.7554/elife.19850] [Citation(s) in RCA: 102] [Impact Index Per Article: 12.8] [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: 07/20/2016] [Accepted: 11/14/2016] [Indexed: 12/24/2022] Open
Abstract
Actin has well established functions in cellular morphogenesis. However, it is not well understood how the various actin assemblies in a cell are kept in a dynamic equilibrium, in particular when cells have to respond to acute signals. Here, we characterize a rapid and transient actin reset in response to increased intracellular calcium levels. Within seconds of calcium influx, the formin INF2 stimulates filament polymerization at the endoplasmic reticulum (ER), while cortical actin is disassembled. The reaction is then reversed within a few minutes. This Calcium-mediated actin reset (CaAR) occurs in a wide range of mammalian cell types and in response to many physiological cues. CaAR leads to transient immobilization of organelles, drives reorganization of actin during cell cortex repair, cell spreading and wound healing, and induces long-lasting changes in gene expression. Our findings suggest that CaAR acts as fundamental facilitator of cellular adaptations in response to acute signals and stress. DOI:http://dx.doi.org/10.7554/eLife.19850.001 Our skeleton plays a vital role in giving shape and structure to our body, it also allows us to make coordinated movements. Similarly, each cell contains a microscopic network of structures and supports called the cytoskeleton that helps cells to adopt specific shapes and is crucial for them to move around. Unlike our skeleton, which is relatively unchanging, the cytoskeleton of each cell constantly changes and adapts to the specific needs of the cell. One part of the cytoskeleton is a dense, flexible meshwork of fibers called the cortex that lies just beneath the surface of the cell. The cortex is constructed using a protein called actin, and many of these proteins join together to form each fiber. When cells need to adapt rapidly to an injury or other sudden changes in their environment they activate a so-called stress response. This response often begins with a rapid increase in the amount of calcium ions inside a cell, which can then trigger changes in actin organization. However, it is not clear how cells under stress are able to globally remodel their actin cytoskeleton without compromising stability and integrity of the cortex. Wales, Schuberth, Aufschnaiter et al. used a range of mammalian cells to investigate how actin responds to stress signals. All cells responded to the resulting influx of calcium ions by deconstructing large parts of the actin cortex and simultaneously forming actin filaments near the center of the cell. Wales, Schuberth, Aufschnaiter et al. termed this response calcium-mediated actin reset (CaAR), as it lasted for only a few minutes before the actin cortex reformed. The experiments show that a protein called INF2 controls CaAR by rapidly removing actin from the cortex and forming new filaments near a cell compartment called the endoplasmic reticulum. CaAR allows cells to rapidly and drastically alter the cortex in response to stress. The experiments also show that this sudden shift in actin can change the activity of certain genes, leading to longer-term effects on the cell. The findings of Wales, Schuberth, Aufschnaiter et al. suggest that calcium ions globally regulate the actin cytoskeleton and hence cell shape and movement under stress. This could be relevant for many important processes and conditions such as wound healing, inflammation and cancer. A future challenge will be to understand the role of CaAR in these processes. DOI:http://dx.doi.org/10.7554/eLife.19850.002
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Affiliation(s)
- Pauline Wales
- Institute of Cell Dynamics and Imaging, University of Muenster, Muenster, Germany.,Cells-In-Motion Cluster of Excellence (EXC1003 - CiM), University of Münster, Muenster, Germany
| | - Christian E Schuberth
- Institute of Cell Dynamics and Imaging, University of Muenster, Muenster, Germany.,Cells-In-Motion Cluster of Excellence (EXC1003 - CiM), University of Münster, Muenster, Germany
| | - Roland Aufschnaiter
- Institute of Cell Dynamics and Imaging, University of Muenster, Muenster, Germany.,Cells-In-Motion Cluster of Excellence (EXC1003 - CiM), University of Münster, Muenster, Germany
| | - Johannes Fels
- Institute of Cell Dynamics and Imaging, University of Muenster, Muenster, Germany.,Cells-In-Motion Cluster of Excellence (EXC1003 - CiM), University of Münster, Muenster, Germany
| | | | - Annette Janning
- Institute of Cell Dynamics and Imaging, University of Muenster, Muenster, Germany.,Cells-In-Motion Cluster of Excellence (EXC1003 - CiM), University of Münster, Muenster, Germany
| | - Christopher P Dlugos
- Institute of Cell Dynamics and Imaging, University of Muenster, Muenster, Germany.,Cells-In-Motion Cluster of Excellence (EXC1003 - CiM), University of Münster, Muenster, Germany.,Medical Clinic D, University Clinic of Muenster, Muenster, Germany
| | - Marco Schäfer-Herte
- Institute of Cell Dynamics and Imaging, University of Muenster, Muenster, Germany.,Cells-In-Motion Cluster of Excellence (EXC1003 - CiM), University of Münster, Muenster, Germany
| | - Christoph Klingner
- Institute of Cell Dynamics and Imaging, University of Muenster, Muenster, Germany.,Cells-In-Motion Cluster of Excellence (EXC1003 - CiM), University of Münster, Muenster, Germany.,AG Molecular Mechanotransduction, Max Planck Institute of Biochemistry, Munich, Germany
| | - Mike Wälte
- Institute of Cell Dynamics and Imaging, University of Muenster, Muenster, Germany.,Cells-In-Motion Cluster of Excellence (EXC1003 - CiM), University of Münster, Muenster, Germany
| | - Julian Kuhlmann
- Institute of Cell Dynamics and Imaging, University of Muenster, Muenster, Germany.,Cells-In-Motion Cluster of Excellence (EXC1003 - CiM), University of Münster, Muenster, Germany
| | - Ekaterina Menis
- Institute of Cell Dynamics and Imaging, University of Muenster, Muenster, Germany.,Cells-In-Motion Cluster of Excellence (EXC1003 - CiM), University of Münster, Muenster, Germany
| | - Laura Hockaday Kang
- Institute of Cell Dynamics and Imaging, University of Muenster, Muenster, Germany.,Cells-In-Motion Cluster of Excellence (EXC1003 - CiM), University of Münster, Muenster, Germany
| | - Kerstin C Maier
- Department of Biochemistry, University of Munich, Munich, Germany
| | - Wenya Hou
- Institute of Biochemistry I, Friedrich Schiller University Jena, Jena, Germany
| | - Antonella Russo
- Institute of Immunology, University of Münster, Münster, Germany
| | - Henry N Higgs
- Department of Biochemistry, Dartmouth Medical School, Hanover, United States
| | | | - Thomas Vogl
- Institute of Immunology, University of Münster, Münster, Germany
| | - Johannes Roth
- Institute of Immunology, University of Münster, Münster, Germany
| | - Britta Qualmann
- Institute of Biochemistry I, Friedrich Schiller University Jena, Jena, Germany
| | - Michael M Kessels
- Institute of Biochemistry I, Friedrich Schiller University Jena, Jena, Germany
| | - Dietmar E Martin
- Department of Biochemistry, University of Munich, Munich, Germany
| | - Bela Mulder
- Theory of Biological Matter, FOM Institute AMOLF, Amsterdam, Netherlands
| | - Roland Wedlich-Söldner
- Institute of Cell Dynamics and Imaging, University of Muenster, Muenster, Germany.,Cells-In-Motion Cluster of Excellence (EXC1003 - CiM), University of Münster, Muenster, Germany
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6
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Abstract
Negative charges in the glycocalyx of red blood cells (RBC) and vascular endothelial cells (EC) facilitate frictionless blood flow through blood vessels. Na+ selectively shields these charges controlling surface electronegativity. The question was addressed whether the ambient Na+ concentration controls RBC-EC interaction. Using atomic force microscopy (AFM) adhesion forces between RBC and endothelial glycocalyx were quantified. A single RBC, mounted on an AFM cantilever, was brought in physical contact with the endothelial surface and then pulled off. Adhesion forces were quantified (i) after enzymatic removal of negative charges in the glycocalyx, (ii) under different ambient Na+ and (iii) after applying the intracellular aldosterone receptor antagonist spironolactone. Removal of negative surface charges increases RBC-EC interaction forces. A stepwise increase of ambient Na+ from 133 to 140 mM does not affect them. However, beyond 140 mM Na+ adhesion forces increase sharply (10% increase of adhesion force per 1 mM increase of Na+). Spironolactone prevents this response. It is concluded that negative charges reduce adhesion between RBC and EC. Ambient Na+ concentration determines the availability of free negative charges. Na+ concentrations in the low physiological range (below 140 mM) allow sufficient amounts of vacant negative charges so that adhesion of RBC to the endothelial surface is small. In contrast, Na+ in the high physiological range (beyond 140 mM) saturates the remaining negative surface charges thus increasing adhesion. Aldosterone receptor blockade by spironolactone prevents Na+ induced RBC adhesion to the endothelial glycocalyx. Extrapolation of in vitro experiments to in vivo conditions leads to the hypothesis that high sodium intake is likely to increase the incidence of thrombotic events.
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Affiliation(s)
- Hans Oberleithner
- Medical Faculty, Institute of Physiology II, University of Münster Münster, Germany
| | - Mike Wälte
- Medical Faculty, Institute of Physiology II, University of Münster Münster, Germany
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7
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Kim SN, Jeibmann A, Halama K, Witte HT, Wälte M, Matzat T, Schillers H, Faber C, Senner V, Paulus W, Klämbt C. ECM stiffness regulates glial migration in Drosophila and mammalian glioma models. Development 2014; 141:3233-42. [DOI: 10.1242/dev.106039] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Cell migration is an important feature of glial cells. Here, we used the Drosophila eye disc to decipher the molecular network controlling glial migration. We stimulated glial motility by pan-glial PDGF receptor (PVR) activation and identified several genes acting downstream of PVR. Drosophila lox is a non-essential gene encoding a secreted protein that stiffens the extracellular matrix (ECM). Glial-specific knockdown of Integrin results in ECM softening. Moreover, we show that lox expression is regulated by Integrin signaling and vice versa, suggesting that a positive-feedback loop ensures a rigid ECM in the vicinity of migrating cells. The general implication of this model was tested in a mammalian glioma model, where a Lox-specific inhibitor unraveled a clear impact of ECM rigidity in glioma cell migration.
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Affiliation(s)
- Su Na Kim
- Institute of Neurobiology, University of Münster, Münster 48149, Germany
| | - Astrid Jeibmann
- Institute of Neuropathology, University Hospital Münster, Münster 48149, Germany
| | - Kathrin Halama
- Institute of Neuropathology, University Hospital Münster, Münster 48149, Germany
| | - Hanna Teresa Witte
- Institute of Neurobiology, University of Münster, Münster 48149, Germany
- Institute of Neuropathology, University Hospital Münster, Münster 48149, Germany
| | - Mike Wälte
- Institute of Physiology II, University Hospital Münster, Münster 48149, Germany
| | - Till Matzat
- Institute of Neurobiology, University of Münster, Münster 48149, Germany
| | - Hermann Schillers
- Institute of Physiology II, University Hospital Münster, Münster 48149, Germany
| | - Cornelius Faber
- Department of Clinical Radiology, University Hospital Münster, Münster 48149, Germany
| | - Volker Senner
- Institute of Neuropathology, University Hospital Münster, Münster 48149, Germany
| | - Werner Paulus
- Institute of Neuropathology, University Hospital Münster, Münster 48149, Germany
| | - Christian Klämbt
- Institute of Neurobiology, University of Münster, Münster 48149, Germany
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8
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Schillers H, Wälte M, Urbanova K, Oberleithner H. Real-time monitoring of cell elasticity reveals oscillating myosin activity. Biophys J 2011; 99:3639-46. [PMID: 21112288 DOI: 10.1016/j.bpj.2010.09.048] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2010] [Revised: 08/30/2010] [Accepted: 09/22/2010] [Indexed: 10/18/2022] Open
Abstract
The cytoskeleton is the physical and biochemical interface for a large variety of cellular processes. Its complex regulation machinery is involved upstream and downstream in various signaling pathways. The cytoskeleton determines the mechanical properties of a cell. Thus, cell elasticity could serve as a parameter reflecting the behavior of the system rather than reflecting the specific properties of isolated components. In this study, we used atomic force microscopy to perform real-time monitoring of cell elasticity unveiling cytoskeletal dynamics of living bronchial epithelial cells. In resting cells, we found a periodic activity of the cytoskeleton. Amplitude and frequency of this spontaneous oscillation were strongly affected by intracellular calcium. Experiments reveal that basal cell elasticity and superimposed elasticity oscillations are caused by the collective action of myosin motor proteins. We characterized the cell as a mechanically multilayered structure, and followed cytoskeletal dynamics in the different layers with high time resolution. In conclusion, the collective activities of the myosin motor proteins define overall mechanical cell dynamics, reflecting specific changes of the chemical and mechanical environment.
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Affiliation(s)
- Hermann Schillers
- Institute of Physiology II, University of Münster, Münster, Germany.
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9
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Olety B, Wälte M, Honnert U, Schillers H, Bähler M. Myosin 1G (Myo1G) is a haematopoietic specific myosin that localises to the plasma membrane and regulates cell elasticity. FEBS Lett 2009; 584:493-9. [PMID: 19968988 DOI: 10.1016/j.febslet.2009.11.096] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [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: 09/03/2009] [Revised: 11/10/2009] [Accepted: 11/30/2009] [Indexed: 11/19/2022]
Abstract
Immune cells navigate through different environments where they experience different mechanical forces. Responses to external forces are determined by the mechanical properties of a cell and they depend to a large extent on the actin-rich cell cortex. We report here that Myo1G, a previously uncharacterised member of class I myosins, is expressed specifically in haematopoietic tissues and cells. It is associated with the plasma membrane. This association is dependent on a conserved PH-domain-like myosin I tail homology motif and the head domain. However, the head domain does not need to be a functional motor. Knockdown of Myo1G in Jurkat cells decreased cell elasticity significantly. We propose that Myo1G regulates cell elasticity by deformations of the actin network at the cell cortex.
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Affiliation(s)
- Balaji Olety
- Institute of General Zoology and Genetics, Westfalian Wilhelms-University Münster, Münster, Germany
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10
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Stumpf A, Wenners-Epping K, Wälte M, Lange T, Koch HG, Häberle J, Dübbers A, Falk S, Kiesel L, Nikova D, Bruns R, Bertram H, Oberleithner H, Schillers H. Physiological concept for a blood based CFTR test. Cell Physiol Biochem 2006; 17:29-36. [PMID: 16543719 DOI: 10.1159/000091457] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
We tested the hypothesis that the cystic fibrosis transmembrane conductance regulator (CFTR) could be involved in the volume regulation of human red blood cells (RBC). Experiments were based on two gadolinium (Gd(3+)) sensitive mechanisms, i.e. inhibition of ATP release (thetaATP(i)) and membrane destabilization. RBC of either cystic fibrosis (CF) patients or healthy donors (non-CF) were exposed to KCl buffer containing Gd(3+). A significantly larger quantity of non-CF RBC (2.55 %) hemolyzed as compared to CF RBC (0.89 %). It was found that both of the Gd(3+) mechanisms simultaneously are needed to achieve hemolysis, since either overriding thetaATP(i) by exogenous ATP addition prevented Gd(3+) induced hemolysis, or mimicking thetaATP(i) by apyrase in absence of Gd(3+) could not trigger hemolysis. Additionally, ion driven volume uptake was found to be a prerequisite for Gd3+ induced hemolysis as chloride and potassium channel blockers reduced the Gd(3+) response. The results show that in non-CF RBC Gd(3+) exerts its dual effect leading to hemolysis. On the contrary, in CF RBC, lacking CFTR dependent ATP release, the sole Gd(3+) effect of membrane destabilization is not sufficient to induce hemolysis similar to non-CF. This concept could form the basis of a novel method suitable for testing CFTR function in a blood sample.
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Affiliation(s)
- Astrid Stumpf
- Institute of Physiology II, University of Muenster, Germany.
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