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Balakrishnan M, Kenworthy AK. Lipid Peroxidation Drives Liquid-Liquid Phase Separation and Disrupts Raft Protein Partitioning in Biological Membranes. J Am Chem Soc 2024; 146:1374-1387. [PMID: 38171000 PMCID: PMC10797634 DOI: 10.1021/jacs.3c10132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 12/06/2023] [Accepted: 12/07/2023] [Indexed: 01/05/2024]
Abstract
The peroxidation of membrane lipids by free radicals contributes to aging, numerous diseases, and ferroptosis, an iron-dependent form of cell death. Peroxidation changes the structure and physicochemical properties of lipids, leading to bilayer thinning, altered fluidity, and increased permeability of membranes in model systems. Whether and how lipid peroxidation impacts the lateral organization of proteins and lipids in biological membranes, however, remains poorly understood. Here, we employ cell-derived giant plasma membrane vesicles (GPMVs) as a model to investigate the impact of lipid peroxidation on ordered membrane domains, often termed membrane rafts. We show that lipid peroxidation induced by the Fenton reaction dramatically enhances the phase separation propensity of GPMVs into coexisting liquid-ordered (Lo) and liquid-disordered (Ld) domains and increases the relative abundance of the disordered phase. Peroxidation also leads to preferential accumulation of peroxidized lipids and 4-hydroxynonenal (4-HNE) adducts in the disordered phase, decreased lipid packing in both Lo and Ld domains, and translocation of multiple classes of raft proteins out of ordered domains. These findings indicate that the peroxidation of plasma membrane lipids disturbs many aspects of membrane rafts, including their stability, abundance, packing, and protein and lipid composition. We propose that these disruptions contribute to the pathological consequences of lipid peroxidation during aging and disease and thus serve as potential targets for therapeutic intervention.
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Affiliation(s)
- Muthuraj Balakrishnan
- Center
for Membrane and Cell Physiology, University
of Virginia, Charlottesville, Virginia 22903, United States
- Department
of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, Virginia 22903, United States
| | - Anne K. Kenworthy
- Center
for Membrane and Cell Physiology, University
of Virginia, Charlottesville, Virginia 22903, United States
- Department
of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, Virginia 22903, United States
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2
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Mayor S, Bhat A, Kusumi A. A Survey of Models of Cell Membranes: Toward a New Understanding of Membrane Organization. Cold Spring Harb Perspect Biol 2023; 15:a041394. [PMID: 37643877 PMCID: PMC10547391 DOI: 10.1101/cshperspect.a041394] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
The cell membrane, the boundary that separates living cells from their environment, has been the subject of study for over a century. The fluid-mosaic model of Singer and Nicolson in 1972 proposed the plasma membrane as a two-dimensional fluid composed of lipids and proteins. Fifty years hence, advances in biophysical and biochemical tools, particularly optical imaging techniques, have allowed for a better understanding of the physical nature, organization, and composition of cell membranes. This has been made possible by visualizing membrane heterogeneities and their dynamics and appreciating the asymmetrical arrangement of lipids in living cell membranes. Despite these advances, mechanisms underlying the local spatiotemporal organization of membrane components remain unclear. This review surveys various models of membrane organization, culminating in a new model that incorporates nonequilibrium processes and forces exerted by interactions with extramembrane elements such as the actin cytoskeleton. The proposed model provides a comprehensive understanding of membrane organization, taking into account the dynamic nature of the cell membrane and its interactions with its immediate environment.
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Affiliation(s)
- Satyajit Mayor
- National Centre for Biological Science, TIFR, Bangalore 560065, India
| | - Abrar Bhat
- National Centre for Biological Science, TIFR, Bangalore 560065, India
| | - Akihiro Kusumi
- Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa 904-0495, Japan; Institute for Integrated Cell-Material Sciences (iCeMS), Kyoto University, Kyoto 606-8501, Japan
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3
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Balakrishnan M, Kenworthy AK. Lipid peroxidation drives liquid-liquid phase separation and disrupts raft protein partitioning in biological membranes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.12.557355. [PMID: 37745342 PMCID: PMC10515805 DOI: 10.1101/2023.09.12.557355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
The peroxidation of membrane lipids by free radicals contributes to aging, numerous diseases, and ferroptosis, an iron-dependent form of cell death. Peroxidation changes the structure, conformation and physicochemical properties of lipids, leading to major membrane alterations including bilayer thinning, altered fluidity, and increased permeability. Whether and how lipid peroxidation impacts the lateral organization of proteins and lipids in biological membranes, however, remains poorly understood. Here, we employ cell-derived giant plasma membrane vesicles (GPMVs) as a model to investigate the impact of lipid peroxidation on ordered membrane domains, often termed membrane rafts. We show that lipid peroxidation induced by the Fenton reaction dramatically enhances phase separation propensity of GPMVs into co-existing liquid ordered (raft) and liquid disordered (non-raft) domains and increases the relative abundance of the disordered, non-raft phase. Peroxidation also leads to preferential accumulation of peroxidized lipids and 4-hydroxynonenal (4-HNE) adducts in the disordered phase, decreased lipid packing in both raft and non-raft domains, and translocation of multiple classes of proteins out of rafts. These findings indicate that peroxidation of plasma membrane lipids disturbs many aspects of membrane rafts, including their stability, abundance, packing, and protein and lipid composition. We propose that these disruptions contribute to the pathological consequences of lipid peroxidation during aging and disease, and thus serve as potential targets for therapeutic intervention.
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Affiliation(s)
- Muthuraj Balakrishnan
- Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, VA USA
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Anne K. Kenworthy
- Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, VA USA
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, VA, USA
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4
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Yoo SW, Waheed AA, Deme P, Tohumeken S, Rais R, Smith MD, DeMarino C, Calabresi PA, Kashanchi F, Freed EO, Slusher BS, Haughey NJ. Inhibition of neutral sphingomyelinase 2 impairs HIV-1 envelope formation and substantially delays or eliminates viral rebound. Proc Natl Acad Sci U S A 2023; 120:e2219543120. [PMID: 37406092 PMCID: PMC10334757 DOI: 10.1073/pnas.2219543120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 04/03/2023] [Indexed: 07/07/2023] Open
Abstract
Although HIV-1 Gag is known to drive viral assembly and budding, the precise mechanisms by which the lipid composition of the plasma membrane is remodeled during assembly are incompletely understood. Here, we provide evidence that the sphingomyelin hydrolase neutral sphingomyelinase 2 (nSMase2) interacts with HIV-1 Gag and through the hydrolysis of sphingomyelin creates ceramide that is necessary for proper formation of the viral envelope and viral maturation. Inhibition or depletion of nSMase2 resulted in the production of noninfectious HIV-1 virions with incomplete Gag lattices lacking condensed conical cores. Inhibition of nSMase2 in HIV-1-infected humanized mouse models with a potent and selective inhibitor of nSMase2 termed PDDC [phenyl(R)-(1-(3-(3,4-dimethoxyphenyl)-2, 6-dimethylimidazo[1,2-b]pyridazin-8-yl) pyrrolidin-3-yl)-carbamate] produced a linear reduction in levels of HIV-1 in plasma. If undetectable plasma levels of HIV-1 were achieved with PDDC treatment, viral rebound did not occur for up to 4 wk when PDDC was discontinued. In vivo and tissue culture results suggest that PDDC selectively kills cells with actively replicating HIV-1. Collectively, this work demonstrates that nSMase2 is a critical regulator of HIV-1 replication and suggests that nSMase2 could be an important therapeutic target with the potential to kill HIV-1-infected cells.
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Affiliation(s)
- Seung-Wan Yoo
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD21210
| | - Abdul A. Waheed
- Virus-Cell Interaction Section, HIV-1 Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute-Frederick, Frederick, MD21702
| | - Pragney Deme
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD21210
| | - Sehmus Tohumeken
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD21210
| | - Rana Rais
- Johns Hopkins Drug Discovery, Johns Hopkins University School of Medicine, Baltimore, MD21205
| | - Matthew D. Smith
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD21210
| | - Catherine DeMarino
- Laboratory of Molecular Virology, George Mason University, Manassas, VA20110
| | - Peter A. Calabresi
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD21210
| | - Fatah Kashanchi
- Laboratory of Molecular Virology, George Mason University, Manassas, VA20110
| | - Eric O. Freed
- Virus-Cell Interaction Section, HIV-1 Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute-Frederick, Frederick, MD21702
| | - Barbara S. Slusher
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD21210
- Johns Hopkins Drug Discovery, Johns Hopkins University School of Medicine, Baltimore, MD21205
- Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD21210
- Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD21210
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD21224
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD21205
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD21210
| | - Norman J. Haughey
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD21210
- Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD21210
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5
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Vurro V, Moschetta M, Bondelli G, Sardar S, Magni A, Sesti V, Paternò GM, Bertarelli C, D'Andrea C, Lanzani G. Membrane Order Effect on the Photoresponse of an Organic Transducer. MEMBRANES 2023; 13:membranes13050538. [PMID: 37233599 DOI: 10.3390/membranes13050538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 05/12/2023] [Accepted: 05/19/2023] [Indexed: 05/27/2023]
Abstract
Non-genetic photostimulation, which allows for control over cellular activity via the use of cell-targeting phototransducers, is widely used nowadays to study and modulate/restore biological functions. This approach relies on non-covalent interactions between the phototransducer and the cell membrane, thus implying that cell conditions and membrane status can dictate the effectiveness of the method. For instance, although immortalized cell lines are traditionally used in photostimulation experiments, it has been demonstrated that the number of passages they undergo is correlated to the worsening of cell conditions. In principle, this could impact cell responsivity against exogenous stressors, including photostimulation. However, these aspects have usually been neglected in previous experiments. In this work, we investigated whether cell passages could affect membrane properties (such as polarity and fluidity). We applied optical spectroscopy and electrophysiological measurements in two different biological models: (i) an epithelial immortalized cell line (HEK-293T cells) and (ii) liposomes. Different numbers of cell passages were compared to a different morphology in the liposome membrane. We demonstrated that cell membranes show a significant decrease in ordered domains upon increasing the passage number. Furthermore, we observed that cell responsivity against external stressors is markedly different between aged and non-aged cells. Firstly, we noted that the thermal-disordering effect that is usually observed in membranes is more evident in aged cells than in non-aged ones. We then set up a photostimulation experiment by using a membrane-targeted azobenzene as a phototransducer (Ziapin2). As an example of a functional consequence of such a condition, we showed that the rate of isomerization of an intramembrane molecular transducer is significantly impaired in aged cells. The reduction in the photoisomerization rate translates in cells with a sustained reduction of the Ziapin2-related hyperpolarization of the membrane potential and an overall increase in the molecule fluorescence. Overall, our results suggest that membrane stimulation strongly depends on membrane order, highlighting the importance of cell passage during the characterization of the stimulation tools. This study can shine light on the correlation between aging and the development of diseases driven by membrane degradation as well as on the different cell responsivities against external stressors, such as temperature and photostimulation.
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Affiliation(s)
- Vito Vurro
- Center for Nano Science and Technology @PoliMi, Istituto Italiano di Tecnologia, 20134 Milan, Italy
| | - Matteo Moschetta
- Center for Nano Science and Technology @PoliMi, Istituto Italiano di Tecnologia, 20134 Milan, Italy
| | - Gaia Bondelli
- Center for Nano Science and Technology @PoliMi, Istituto Italiano di Tecnologia, 20134 Milan, Italy
- Department of Physics, Politecnico di Milano, 20133 Milan, Italy
| | - Samim Sardar
- Center for Nano Science and Technology @PoliMi, Istituto Italiano di Tecnologia, 20134 Milan, Italy
| | - Arianna Magni
- Center for Nano Science and Technology @PoliMi, Istituto Italiano di Tecnologia, 20134 Milan, Italy
- Department of Physics, Politecnico di Milano, 20133 Milan, Italy
| | - Valentina Sesti
- Center for Nano Science and Technology @PoliMi, Istituto Italiano di Tecnologia, 20134 Milan, Italy
- Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, 20133 Milan, Italy
| | - Giuseppe Maria Paternò
- Center for Nano Science and Technology @PoliMi, Istituto Italiano di Tecnologia, 20134 Milan, Italy
- Department of Physics, Politecnico di Milano, 20133 Milan, Italy
| | - Chiara Bertarelli
- Center for Nano Science and Technology @PoliMi, Istituto Italiano di Tecnologia, 20134 Milan, Italy
- Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, 20133 Milan, Italy
| | - Cosimo D'Andrea
- Center for Nano Science and Technology @PoliMi, Istituto Italiano di Tecnologia, 20134 Milan, Italy
- Department of Physics, Politecnico di Milano, 20133 Milan, Italy
| | - Guglielmo Lanzani
- Center for Nano Science and Technology @PoliMi, Istituto Italiano di Tecnologia, 20134 Milan, Italy
- Department of Physics, Politecnico di Milano, 20133 Milan, Italy
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6
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Montalbo RCK, Tu HL. Micropatterning of functional lipid bilayer assays for quantitative bioanalysis. BIOMICROFLUIDICS 2023; 17:031302. [PMID: 37179590 PMCID: PMC10171888 DOI: 10.1063/5.0145997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Accepted: 04/24/2023] [Indexed: 05/15/2023]
Abstract
Interactions of the cell with its environment are mediated by the cell membrane and membrane-localized molecules. Supported lipid bilayers have enabled the recapitulation of the basic properties of cell membranes and have been broadly used to further our understanding of cellular behavior. Coupled with micropatterning techniques, lipid bilayer platforms have allowed for high throughput assays capable of performing quantitative analysis at a high spatiotemporal resolution. Here, an overview of the current methods of the lipid membrane patterning is presented. The fabrication and pattern characteristics are briefly described to present an idea of the quality and notable features of the methods, their utilizations for quantitative bioanalysis, as well as to highlight possible directions for the advanced micropatterning lipid membrane assays.
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7
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Shimokawa N, Hamada T. Physical Concept to Explain the Regulation of Lipid Membrane Phase Separation under Isothermal Conditions. Life (Basel) 2023; 13:life13051105. [PMID: 37240749 DOI: 10.3390/life13051105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 04/21/2023] [Accepted: 04/22/2023] [Indexed: 05/28/2023] Open
Abstract
Lateral phase separation within lipid bilayer membranes has attracted considerable attention in the fields of biophysics and cell biology. Living cells organize laterally segregated compartments, such as raft domains in an ordered phase, and regulate their dynamic structures under isothermal conditions to promote cellular functions. Model membrane systems with minimum components are powerful tools for investigating the basic phenomena of membrane phase separation. With the use of such model systems, several physicochemical characteristics of phase separation have been revealed. This review focuses on the isothermal triggering of membrane phase separation from a physical point of view. We consider the free energy of the membrane that describes lateral phase separation and explain the experimental results of model membranes to regulate domain formation under isothermal conditions. Three possible regulation factors are discussed: electrostatic interactions, chemical reactions and membrane tension. These findings may contribute to a better understanding of membrane lateral organization within living cells that function under isothermal conditions and could be useful for the development of artificial cell engineering.
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Affiliation(s)
- Naofumi Shimokawa
- School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi 923-1292, Ishikawa, Japan
| | - Tsutomu Hamada
- School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi 923-1292, Ishikawa, Japan
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8
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Deng Z, Li J, Liu H, Luo T, Yang Y, Yang M, Chen X. A light-controlled DNA nanothermometer for temperature sensing in the cellular membrane microenvironment. Biosens Bioelectron 2022; 216:114627. [PMID: 35973279 DOI: 10.1016/j.bios.2022.114627] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Revised: 08/02/2022] [Accepted: 08/05/2022] [Indexed: 11/16/2022]
Abstract
Precise sensing of cellular temperature is one significant yet challenge task for studying miscellaneous biological processes. Herein, we report a light-controlled DNA nanothermometer that allow for real-time thermal sensing in extracellular microscope with high spatiotemporal resolution. The light-controlled DNA nanothermometer three key elements: a thermal-sensitive molecular beacon (MB) labelled with fluorophore Cy5 and Cy3 at its 5' and 3' termini, an inhibitor strand containing two photocleavable linkers (pc-linker), and a biotin modified strand, which could modify this three-strand hybridization complex onto the cell surface. Upon exposing to UV light irradiation, the light-controlled DNA nanothermometer could be remotely activated and enable to perform highly sensitive and practical ratiometric temperature sensing. Meanwhile, the light-controlled DNA nanothermometer could conduct temperature sensing in the extracellular microscope and demonstrates desirable sensitivity, excellent reversibility, and quantitative ability for extracellular temperature measurement. Therefore, this light-controlled DNA can serve as a promising tool for elucidating thermal-related cell physiological and pathological processes.
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Affiliation(s)
- Zhiwei Deng
- Hunan Provincial Key Laboratory of Micro & Nano Materials Interface Science, College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, China
| | - Jiacheng Li
- Hunan Provincial Key Laboratory of Micro & Nano Materials Interface Science, College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, China
| | - Hui Liu
- Hunan Provincial Key Laboratory of Micro & Nano Materials Interface Science, College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, China
| | - Tong Luo
- Hunan Provincial Key Laboratory of Micro & Nano Materials Interface Science, College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, China
| | - Yanjing Yang
- Hunan Provincial Key Laboratory of Micro & Nano Materials Interface Science, College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, China.
| | - Minghui Yang
- Hunan Provincial Key Laboratory of Micro & Nano Materials Interface Science, College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, China.
| | - Xiang Chen
- Department of Dermatology, Xiangya Hospital, Central South University, Changsha, Hunan, 410000, China; National Engineering Research Center of Personalized Diagnostic and Therapeutic Technology, Central South University, Changsha, 410083, China.
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9
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Ureña J, Knight A, Lee IH. Membrane Cargo Density-Dependent Interaction between Protein and Lipid Domains on the Giant Unilamellar Vesicles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:4702-4712. [PMID: 35385290 DOI: 10.1021/acs.langmuir.2c00247] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Protein cargos anchored on the lipid membrane can be segregated by fluidic domain phase separation. Lipid membranes at certain compositions may separate into lipid domains to segregate cargos, and protein cargos themselves may be involved in protein condensate domain formation with multivalent binding proteins to segregate cargos. Recent studies suggest that these two driving forces of phase separation closely interact on the lipid membranes to promote codomain formation. In this report, we studied the effect of cargo density on the outcome of the cargo phase separation on giant unilamellar vesicles. Proteins and lipids are connected only by the anchored cargos, so it was originally hypothesized that higher cargo density would increase the degree of interaction between the lipid and protein domains, promoting more phase separation. However, fluorescence image analysis on different cargo densities showed that the cooperative domain formation and steric pressure are at a tug of war opposing each other. Cooperative domain formation is dominant under lower anchor density conditions, and above a threshold density, steric pressure was dominant opposing the domain formation. The result suggests that the cargo density is a key parameter affecting the outcome of cargo organization on the lipid membranes by phase separation.
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Affiliation(s)
- Juan Ureña
- Department of Chemistry and Biochemistry, Montclair State University, Montclair, New Jersey 07043, United States
| | - Ashlynn Knight
- Department of Biology, Montclair State University, Montclair, New Jersey 07043, United States
| | - Il-Hyung Lee
- Department of Chemistry and Biochemistry, Montclair State University, Montclair, New Jersey 07043, United States
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10
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Fricke N, Raghunathan K, Tiwari A, Stefanski KM, Balakrishnan M, Waterson AG, Capone R, Huang H, Sanders CR, Bauer JA, Kenworthy AK. High-Content Imaging Platform to Discover Chemical Modulators of Plasma Membrane Rafts. ACS CENTRAL SCIENCE 2022; 8:370-378. [PMID: 35355811 PMCID: PMC8961798 DOI: 10.1021/acscentsci.1c01058] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Indexed: 05/05/2023]
Abstract
Plasma membrane organization profoundly impacts cellular functionality. A well-known mechanism underlying this organization is through nanoscopic clustering of distinct lipids and proteins in membrane rafts. Despite their physiological importance, rafts remain a difficult-to-study aspect of membrane organization, in part because of the paucity of chemical tools to experimentally modulate their properties. Methods to selectively target rafts for therapeutic purposes are also currently lacking. To tackle these problems, we developed a high-throughput screen and an accompanying image analysis pipeline to identify small molecules that enhance or inhibit raft formation. Cell-derived giant plasma membrane vesicles were used as the experimental platform. A proof-of-principle screen using a bioactive lipid library demonstrates that this method is robust and capable of validating established raft modulators including C6- and C8-ceramide, miltefosine, and epigallocatechin gallate as well as identifying new ones. The platform we describe here represents a powerful tool to discover new chemical approaches to manipulate rafts and their components.
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Affiliation(s)
- Nico Fricke
- Department
of Molecular Physiology and Biophysics, Vanderbilt School of Medicine, Nashville, Tennessee 37232, United States
| | - Krishnan Raghunathan
- Department
of Molecular Physiology and Biophysics, Vanderbilt School of Medicine, Nashville, Tennessee 37232, United States
| | - Ajit Tiwari
- Department
of Molecular Physiology and Biophysics, Vanderbilt School of Medicine, Nashville, Tennessee 37232, United States
| | - Katherine M. Stefanski
- Department
of Biochemistry, Vanderbilt School of Medicine, Nashville, Tennessee 37240, United States
| | - Muthuraj Balakrishnan
- Center
for Membrane and Cell Physiology and Department of Molecular Physiology
and Biological Physics, University of Virginia
School of Medicine, Charlottesville, Virginia 22903, United States
| | - Alex G. Waterson
- Department
of Pharmacology, Vanderbilt School of Medicine, Nashville, Tennessee 37232, United States
| | - Ricardo Capone
- Department
of Molecular Physiology and Biophysics, Vanderbilt School of Medicine, Nashville, Tennessee 37232, United States
| | - Hui Huang
- Department
of Biochemistry, Vanderbilt School of Medicine, Nashville, Tennessee 37240, United States
| | - Charles R. Sanders
- Department
of Biochemistry, Vanderbilt School of Medicine, Nashville, Tennessee 37240, United States
| | - Joshua A. Bauer
- Department
of Biochemistry, Vanderbilt School of Medicine, Nashville, Tennessee 37240, United States
- Vanderbilt
Institute of Chemical Biology, High-Throughput Screening Facility, Vanderbilt School of Medicine, Nashville, Tennessee 37232, United States
| | - Anne K. Kenworthy
- Department
of Molecular Physiology and Biophysics, Vanderbilt School of Medicine, Nashville, Tennessee 37232, United States
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11
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Kenworthy AK, Schmieder SS, Raghunathan K, Tiwari A, Wang T, Kelly CV, Lencer WI. Cholera Toxin as a Probe for Membrane Biology. Toxins (Basel) 2021; 13:543. [PMID: 34437414 PMCID: PMC8402489 DOI: 10.3390/toxins13080543] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2021] [Revised: 07/23/2021] [Accepted: 07/29/2021] [Indexed: 12/26/2022] Open
Abstract
Cholera toxin B-subunit (CTxB) has emerged as one of the most widely utilized tools in membrane biology and biophysics. CTxB is a homopentameric stable protein that binds tightly to up to five GM1 glycosphingolipids. This provides a robust and tractable model for exploring membrane structure and its dynamics including vesicular trafficking and nanodomain assembly. Here, we review important advances in these fields enabled by use of CTxB and its lipid receptor GM1.
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Affiliation(s)
- Anne K. Kenworthy
- Center for Membrane and Cell Physiology and Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, VA 22903, USA; (A.T.); (T.W.)
| | - Stefanie S. Schmieder
- Division of Gastroenterology, Boston Children’s Hospital, Boston, MA 02115, USA;
- Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA
- Harvard Digestive Diseases Center, Boston, MA 02115, USA
| | - Krishnan Raghunathan
- Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15224, USA;
| | - Ajit Tiwari
- Center for Membrane and Cell Physiology and Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, VA 22903, USA; (A.T.); (T.W.)
| | - Ting Wang
- Center for Membrane and Cell Physiology and Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, VA 22903, USA; (A.T.); (T.W.)
| | - Christopher V. Kelly
- Department of Physics and Astronomy, Wayne State University, Detroit, MI 48201, USA
| | - Wayne I. Lencer
- Division of Gastroenterology, Boston Children’s Hospital, Boston, MA 02115, USA;
- Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA
- Harvard Digestive Diseases Center, Boston, MA 02115, USA
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12
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Kusumi A, Fujiwara TK, Tsunoyama TA, Kasai RS, Liu AA, Hirosawa KM, Kinoshita M, Matsumori N, Komura N, Ando H, Suzuki KGN. Defining raft domains in the plasma membrane. Traffic 2021; 21:106-137. [PMID: 31760668 DOI: 10.1111/tra.12718] [Citation(s) in RCA: 71] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 11/19/2019] [Accepted: 11/20/2019] [Indexed: 01/03/2023]
Abstract
Many plasma membrane (PM) functions depend on the cholesterol concentration in the PM in strikingly nonlinear, cooperative ways: fully functional in the presence of physiological cholesterol levels (35~45 mol%), and nonfunctional below 25 mol% cholesterol; namely, still in the presence of high concentrations of cholesterol. This suggests the involvement of cholesterol-based complexes/domains formed cooperatively. In this review, by examining the results obtained by using fluorescent lipid analogs and avoiding the trap of circular logic, often found in the raft literature, we point out the fundamental similarities of liquid-ordered (Lo)-phase domains in giant unilamellar vesicles, Lo-phase-like domains formed at lower temperatures in giant PM vesicles, and detergent-resistant membranes: these domains are formed by cooperative interactions of cholesterol, saturated acyl chains, and unsaturated acyl chains, in the presence of >25 mol% cholesterol. The literature contains evidence, indicating that the domains formed by the same basic cooperative molecular interactions exist and play essential roles in signal transduction in the PM. Therefore, as a working definition, we propose that raft domains in the PM are liquid-like molecular complexes/domains formed by cooperative interactions of cholesterol with saturated acyl chains as well as unsaturated acyl chains, due to saturated acyl chains' weak multiple accommodating interactions with cholesterol and cholesterol's low miscibility with unsaturated acyl chains and TM proteins. Molecules move within raft domains and exchange with those in the bulk PM. We provide a logically established collection of fluorescent lipid probes that preferentially partition into raft and non-raft domains, as defined here, in the PM.
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Affiliation(s)
- Akihiro Kusumi
- Membrane Cooperativity Unit, Okinawa Institute of Science and Technology Graduate University (OIST), Okinawa, Japan.,Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Kyoto, Japan
| | - Takahiro K Fujiwara
- Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Kyoto, Japan
| | - Taka A Tsunoyama
- Membrane Cooperativity Unit, Okinawa Institute of Science and Technology Graduate University (OIST), Okinawa, Japan
| | - Rinshi S Kasai
- Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | - An-An Liu
- Tianjin Key Laboratory of Biosensing and Molecular Recognition, Research Center for Analytical Sciences, College of Chemistry, Nankai University, Tianjin, P. R. China
| | - Koichiro M Hirosawa
- Center for Highly Advanced Integration of Nano and Life Sciences (G-CHAIN), Gifu University, Gifu, Japan
| | - Masanao Kinoshita
- Department of Chemistry, Faculty of Science, Kyushu University, Fukuoka, Japan
| | - Nobuaki Matsumori
- Department of Chemistry, Faculty of Science, Kyushu University, Fukuoka, Japan
| | - Naoko Komura
- Center for Highly Advanced Integration of Nano and Life Sciences (G-CHAIN), Gifu University, Gifu, Japan
| | - Hiromune Ando
- Center for Highly Advanced Integration of Nano and Life Sciences (G-CHAIN), Gifu University, Gifu, Japan
| | - Kenichi G N Suzuki
- Center for Highly Advanced Integration of Nano and Life Sciences (G-CHAIN), Gifu University, Gifu, Japan
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13
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Capone R, Tiwari A, Hadziselimovic A, Peskova Y, Hutchison JM, Sanders CR, Kenworthy AK. The C99 domain of the amyloid precursor protein resides in the disordered membrane phase. J Biol Chem 2021; 296:100652. [PMID: 33839158 PMCID: PMC8113881 DOI: 10.1016/j.jbc.2021.100652] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 04/02/2021] [Accepted: 04/07/2021] [Indexed: 12/11/2022] Open
Abstract
Processing of the amyloid precursor protein (APP) via the amyloidogenic pathway is associated with the etiology of Alzheimer's disease. The cleavage of APP by β-secretase to generate the transmembrane 99-residue C-terminal fragment (C99) and subsequent processing of C99 by γ-secretase to yield amyloid-β (Aβ) peptides are essential steps in this pathway. Biochemical evidence suggests that amyloidogenic processing of C99 occurs in cholesterol- and sphingolipid-enriched liquid-ordered phase membrane rafts. However, direct evidence that C99 preferentially associates with these rafts has remained elusive. Here, we tested this by quantifying the affinity of C99-GFP for raft domains in cell-derived giant plasma membrane vesicles (GPMVs). We found that C99 was essentially excluded from ordered domains in vesicles from HeLa cells, undifferentiated SH-SY5Y cells, or SH-SY5Y-derived neurons; instead, ∼90% of C99 partitioned into disordered domains. The strong association of C99 with disordered domains occurred independently of its cholesterol-binding activity or homodimerization, or of the presence of the familial Alzheimer disease Arctic mutation (APP E693G). Finally, through biochemical studies we confirmed previous results, which showed that C99 is processed in the plasma membrane by α-secretase, in addition to the well-known γ-secretase. These findings suggest that C99 itself lacks an intrinsic affinity for raft domains, implying that either i) amyloidogenic processing of the protein occurs in disordered regions of the membrane, ii) processing involves a marginal subpopulation of C99 found in rafts, or iii) as-yet-unidentified protein-protein interactions with C99 in living cells drive this protein into membrane rafts to promote its cleavage therein.
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Affiliation(s)
- Ricardo Capone
- Department of Biochemistry, Vanderbilt University, Nashville, Tennessee, USA; Center for Structural Biology, Vanderbilt University, Nashville, Tennessee, USA; Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, USA
| | - Ajit Tiwari
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, USA
| | | | - Yelena Peskova
- Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, Virginia, USA
| | - James M Hutchison
- Department of Biochemistry, Vanderbilt University, Nashville, Tennessee, USA
| | - Charles R Sanders
- Department of Biochemistry, Vanderbilt University, Nashville, Tennessee, USA; Center for Structural Biology, Vanderbilt University, Nashville, Tennessee, USA; Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Anne K Kenworthy
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, USA.
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14
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Kamble S, Patil S, Kulkarni M, Appala VRM. Interleaflet Decoupling in a Lipid Bilayer at Excess Cholesterol Probed by Spectroscopic Ellipsometry and Simulations. J Membr Biol 2020; 253:647-659. [PMID: 33221946 DOI: 10.1007/s00232-020-00156-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 11/11/2020] [Indexed: 11/26/2022]
Abstract
Artificial lipid membranes are often investigated as a replica of the cell membrane in the form of supported lipid bilayers (SLBs). In SLBs, the phase state of a lipid bilayer strongly depends on the presence of molecules such as cholesterol, ceramide, and physical parameters such as temperature. Cholesterol is a key molecule of biological membranes and it exerts condensing effect on lipid bilayers. In this paper, we demonstrate the influence of excess cholesterol content on a supported lipid bilayer of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) (fluid-phase) using spectroscopic ellipsometry (SE) and coarse-grained (CG) molecular dynamics (MD) simulations. The results show the condensation effect due to cholesterol addition up to 30% and interleaflet decoupling at excess cholesterol beyond 30%. SE results show the separation of individual leaflets of the bilayer and influence of cholesterol on the biophysical properties such as thickness and optical index. CG simulations were performed at different ratios of DOPC:cholesterol mixtures to explore cholesterol-driven bilayer properties and stability. The simulations displayed the accumulation of cholesterol molecules at the interface of the lower and upper leaflets of the bilayer, thus leading to undulations in the bilayer. This work reports the successful application of SE technique to study lipid-cholesterol interactions for the first time.
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Affiliation(s)
- Sagar Kamble
- Department of Applied Physics, Defence Institute of Advanced Technology (DIAT) DU, Girinagar, Pune, India
| | - Snehal Patil
- Department of Applied Physics, Defence Institute of Advanced Technology (DIAT) DU, Girinagar, Pune, India
| | - Mandar Kulkarni
- Division of Biophysical Chemistry, Chemical Center, Lund University, 22100, Lund, Sweden.
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15
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Castello-Serrano I, Lorent JH, Ippolito R, Levental KR, Levental I. Myelin-Associated MAL and PLP Are Unusual among Multipass Transmembrane Proteins in Preferring Ordered Membrane Domains. J Phys Chem B 2020; 124:5930-5939. [PMID: 32436385 PMCID: PMC7792449 DOI: 10.1021/acs.jpcb.0c03028] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Eukaryotic membranes can be partitioned into lipid-driven membrane microdomains called lipid rafts, which function to sort lipids and proteins in the plane of the membrane. As protein selectivity underlies all functions of lipid rafts, there has been significant interest in understanding the structural and molecular determinants of raft affinity. Such determinants have been described for lipids and single-spanning transmembrane proteins; however, how multipass transmembrane proteins (TMPs) partition between ordered and disordered phases has not been widely explored. Here we used cell-derived giant plasma membrane vesicles (GPMVs) to systematically measure multipass TMP partitioning to ordered membrane domains. Across a set of 24 structurally and functionally diverse multipass TMPs, the large majority (92%) had minimal raft affinity. The only exceptions were two myelin-associated four-pass TMPs, myelin and lymphocyte protein (MAL), and proteo lipid protein (PLP). We characterized the potential mechanisms for their exceptional raft affinity and observed that PLP requires cholesterol and sphingolipids for optimal association with ordered membrane domains and that PLP and MAL appear to compete for cholesterol-mediated raft affinity. These observations suggest broad conclusions about the composition of ordered membrane domains in cells and point to previously unrecognized drivers of raft affinity for multipass transmembrane proteins.
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Affiliation(s)
- Ivan Castello-Serrano
- Department of Integrative Biology and Pharmacology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Joseph H Lorent
- Department of Integrative Biology and Pharmacology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Rossana Ippolito
- Department of Integrative Biology and Pharmacology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Kandice R Levental
- Department of Integrative Biology and Pharmacology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Ilya Levental
- Department of Integrative Biology and Pharmacology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
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16
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Structured clustering of the glycosphingolipid GM1 is required for membrane curvature induced by cholera toxin. Proc Natl Acad Sci U S A 2020; 117:14978-14986. [PMID: 32554490 DOI: 10.1073/pnas.2001119117] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
AB5 bacterial toxins and polyomaviruses induce membrane curvature as a mechanism to facilitate their entry into host cells. How membrane bending is accomplished is not yet fully understood but has been linked to the simultaneous binding of the pentameric B subunit to multiple copies of glycosphingolipid receptors. Here, we probe the toxin membrane binding and internalization mechanisms by using a combination of superresolution and polarized localization microscopy. We show that cholera toxin subunit B (CTxB) can induce membrane curvature only when bound to multiple copies of its glycosphingolipid receptor, GM1, and the ceramide structure of GM1 is likely not a determinant of this activity as assessed in model membranes. A mutant CTxB capable of binding only a single GM1 fails to generate curvature either in model membranes or in cells, and clustering the mutant CTxB-single-GM1 complexes by antibody cross-linking does not rescue the membrane curvature phenotype. We conclude that both the multiplicity and specific geometry of GM1 binding sites are necessary for the induction of membrane curvature. We expect this to be a general rule of membrane behavior for all AB5 toxins and polyomaviruses that bind glycosphingolipids to invade host cells.
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17
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Peripheral myelin protein 22 preferentially partitions into ordered phase membrane domains. Proc Natl Acad Sci U S A 2020; 117:14168-14177. [PMID: 32513719 PMCID: PMC7322011 DOI: 10.1073/pnas.2000508117] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The preferential partitioning of single-span membrane proteins for ordered phase domains in phase-separated membranes is now reasonably well understood, but little is known about this phase preference for multispan helical membrane proteins. Here, it is shown that the disease-linked tetraspan membrane protein, PMP22, displays a pronounced preference to partition into the ordered phase, a preference that is reversed by disease mutations. This phase preference may be related to the role of PMP22 in cholesterol homeostasis in myelinating Schwann cells, a role that is also known to be disrupted under conditions of Charcot–Marie–Tooth disease (CMTD) peripheral neuropathy caused by pmp22 mutations. The ordered environment of cholesterol-rich membrane nanodomains is thought to exclude many transmembrane (TM) proteins. Nevertheless, some multispan helical transmembrane proteins have been proposed to partition into these environments. Here, giant plasma membrane vesicles (GPMVs) were employed to quantitatively show that the helical tetraspan peripheral myelin protein 22 (PMP22) exhibits a pronounced preference for, promotes the formation of, and stabilizes ordered membrane domains. Neither S-palmitoylation of PMP22 nor its putative cholesterol binding motifs are required for this preference. In contrast, Charcot–Marie–Tooth disease-causing mutations that disrupt the stability of PMP22 tertiary structure reduce or eliminate this preference in favor of the disordered phase. These studies demonstrate that the ordered phase preference of PMP22 derives from global structural features associated with the folded form of this protein, providing a glimpse at the structural factors that promote raft partitioning for multispan helical membrane proteins.
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18
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Pinigin KV, Kondrashov OV, Jiménez-Munguía I, Alexandrova VV, Batishchev OV, Galimzyanov TR, Akimov SA. Elastic deformations mediate interaction of the raft boundary with membrane inclusions leading to their effective lateral sorting. Sci Rep 2020; 10:4087. [PMID: 32139760 PMCID: PMC7058020 DOI: 10.1038/s41598-020-61110-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 02/18/2020] [Indexed: 02/06/2023] Open
Abstract
Liquid-ordered lipid domains represent a lateral inhomogeneity in cellular membranes. These domains have elastic and physicochemical properties different from those of the surrounding membrane. In particular, their thickness exceeds that of the disordered membrane. Thus, elastic deformations arise at the domain boundary in order to compensate for the thickness mismatch. In equilibrium, the deformations lead to an incomplete register of monolayer ordered domains: the elastic energy is minimal if domains in opposing monolayers lie on the top of each other, and their boundaries are laterally shifted by about 3 nm. This configuration introduces a region, composed of one ordered and one disordered monolayers, with an intermediate bilayer thickness. Besides, a jump in a local monolayer curvature takes place in this intermediate region, concentrating here most of the elastic stress. This region can participate in a lateral sorting of membrane inclusions by offering them an optimal bilayer thickness and local curvature conditions. In the present study, we consider the sorting of deformable lipid inclusions, undeformable peripheral and deeply incorporated peptide inclusions, and undeformable transmembrane inclusions of different molecular geometry. With rare exceptions, all types of inclusions have an affinity to the ordered domain boundary as compared to the bulk phases. The optimal lateral distribution of inclusions allows relaxing the elastic stress at the boundary of domains.
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Affiliation(s)
- Konstantin V Pinigin
- A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 31/4 Leninskiy prospekt, Moscow, 119071, Russia
| | - Oleg V Kondrashov
- A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 31/4 Leninskiy prospekt, Moscow, 119071, Russia
| | - Irene Jiménez-Munguía
- National University of Science and Technology "MISiS", 4 Leninskiy prospect, Moscow, 119049, Russia
| | | | - Oleg V Batishchev
- A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 31/4 Leninskiy prospekt, Moscow, 119071, Russia
| | - Timur R Galimzyanov
- A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 31/4 Leninskiy prospekt, Moscow, 119071, Russia
| | - Sergey A Akimov
- A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 31/4 Leninskiy prospekt, Moscow, 119071, Russia.
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19
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Skinkle AD, Levental KR, Levental I. Cell-Derived Plasma Membrane Vesicles Are Permeable to Hydrophilic Macromolecules. Biophys J 2020; 118:1292-1300. [PMID: 32053777 DOI: 10.1016/j.bpj.2019.12.040] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 12/09/2019] [Accepted: 12/23/2019] [Indexed: 12/22/2022] Open
Abstract
Giant plasma membrane vesicles (GPMVs) are a widely used experimental platform for biochemical and biophysical analysis of isolated mammalian plasma membranes (PMs). A core advantage of these vesicles is that they maintain the native lipid and protein diversity of the PM while affording the experimental flexibility of synthetic giant vesicles. In addition to fundamental investigations of PM structure and composition, GPMVs have been used to evaluate the binding of proteins and small molecules to cell-derived membranes and the permeation of drug-like molecules through them. An important assumption of such experiments is that GPMVs are sealed, i.e., that permeation occurs by diffusion through the hydrophobic core rather than through hydrophilic pores. Here, we demonstrate that this assumption is often incorrect. We find that most GPMVs isolated using standard preparations are passively permeable to various hydrophilic solutes as large as 40 kDa, in contrast to synthetic giant unilamellar vesicles. We attribute this leakiness to stable, relatively large, and heterogeneous pores formed by rupture of vesicles from cells. Finally, we identify preparation conditions that minimize poration and allow evaluation of sealed GPMVs. These unexpected observations of GPMV poration are important for interpreting experiments utilizing GPMVs as PM models, particularly for drug permeation and membrane asymmetry.
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Affiliation(s)
- Allison D Skinkle
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Houston, Texas; Biological and Biomedical Sciences Program, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Kandice R Levental
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Houston, Texas
| | - Ilya Levental
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Houston, Texas.
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20
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Berselli GB, Sarangi NK, Ramadurai S, Murphy PV, Keyes TE. Microcavity-Supported Lipid Membranes: Versatile Platforms for Building Asymmetric Lipid Bilayers and for Protein Recognition. ACS APPLIED BIO MATERIALS 2019; 2:3404-3417. [DOI: 10.1021/acsabm.9b00378] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Guilherme B. Berselli
- School of Chemical Sciences and National Centre for Sensor Research, Dublin City University, Dublin 9, Ireland
| | - Nirod Kumar Sarangi
- School of Chemical Sciences and National Centre for Sensor Research, Dublin City University, Dublin 9, Ireland
| | - Sivaramakrishnan Ramadurai
- School of Chemical Sciences and National Centre for Sensor Research, Dublin City University, Dublin 9, Ireland
| | - Paul V. Murphy
- School of Chemistry, NUI Galway, University Road, Galway, Ireland
| | - Tia E. Keyes
- School of Chemical Sciences and National Centre for Sensor Research, Dublin City University, Dublin 9, Ireland
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21
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Moreno-Pescador G, Florentsen CD, Østbye H, Sønder SL, Boye TL, Veje EL, Sonne AK, Semsey S, Nylandsted J, Daniels R, Bendix PM. Curvature- and Phase-Induced Protein Sorting Quantified in Transfected Cell-Derived Giant Vesicles. ACS NANO 2019; 13:6689-6701. [PMID: 31199124 DOI: 10.1021/acsnano.9b01052] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Eukaryotic cells possess a dynamic network of membranes that vary in lipid composition. To perform numerous biological functions, cells modulate their shape and the lateral organization of proteins associated with membranes. The modulation is generally facilitated by physical cues that recruit proteins to specific regions of the membrane. Analyzing these cues is difficult due to the complexity of the membrane conformations that exist in cells. Here, we examine how different types of membrane proteins respond to changes in curvature and to lipid phases found in the plasma membrane. By using giant plasma membrane vesicles derived from transfected cells, the proteins were positioned in the correct orientation and the analysis was performed in plasma membranes with a biological composition. Nanoscale membrane curvatures were generated by extracting nanotubes from these vesicles with an optical trap. The viral membrane protein neuraminidase was not sensitive to curvature, but it did exhibit strong partitioning (coefficient of K = 0.16) disordered membrane regions. In contrast, the membrane repair protein annexin 5 showed a preference for nanotubes with a density up to 10-15 times higher than that on the more flat vesicle membrane. The investigation of nanoscale effects in isolated plasma membranes provides a quantitative platform for studying peripheral and integral membrane proteins in their natural environment.
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Affiliation(s)
| | | | - Henrik Østbye
- Department of Biochemistry and Biophysics , Stockholm University , 10691 Stockholm , Sweden
| | - Stine L Sønder
- Membrane Integrity Group, Unit for Cell Death and Metabolism, Center for Autophagy, Recycling and Disease , Danish Cancer Society Research Center , Strandboulevarden 49 , DK-2100 Copenhagen , Denmark
| | - Theresa L Boye
- Membrane Integrity Group, Unit for Cell Death and Metabolism, Center for Autophagy, Recycling and Disease , Danish Cancer Society Research Center , Strandboulevarden 49 , DK-2100 Copenhagen , Denmark
| | - Emilie L Veje
- Niels Bohr Institute , University of Copenhagen , DK-2100 Copenhagen , Denmark
| | - Alexander K Sonne
- Niels Bohr Institute , University of Copenhagen , DK-2100 Copenhagen , Denmark
| | - Szabolcs Semsey
- Niels Bohr Institute , University of Copenhagen , DK-2100 Copenhagen , Denmark
| | - Jesper Nylandsted
- Membrane Integrity Group, Unit for Cell Death and Metabolism, Center for Autophagy, Recycling and Disease , Danish Cancer Society Research Center , Strandboulevarden 49 , DK-2100 Copenhagen , Denmark
- Department of Cellular and Molecular Medicine, Faculty of Health Sciences , University of Copenhagen , DK-2200 Copenhagen N , Denmark
| | - Robert Daniels
- Department of Biochemistry and Biophysics , Stockholm University , 10691 Stockholm , Sweden
| | - Poul Martin Bendix
- Niels Bohr Institute , University of Copenhagen , DK-2100 Copenhagen , Denmark
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22
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Lin X, Gorfe AA, Levental I. Protein Partitioning into Ordered Membrane Domains: Insights from Simulations. Biophys J 2019; 114:1936-1944. [PMID: 29694870 DOI: 10.1016/j.bpj.2018.03.020] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Revised: 03/09/2018] [Accepted: 03/22/2018] [Indexed: 11/24/2022] Open
Abstract
Cellular membranes are laterally organized into domains of distinct structures and compositions by the differential interaction affinities between various membrane lipids and proteins. A prominent example of such structures are lipid rafts, which are ordered, tightly packed domains that have been widely implicated in cellular processes. The functionality of raft domains is driven by their selective recruitment of specific membrane proteins to regulate their interactions and functions; however, there have been few general insights into the factors that determine the partitioning of membrane proteins between coexisting liquid domains. In this work, we used extensive coarse-grained and atomistic molecular dynamics simulations, potential of mean force calculations, and conceptual models to describe the partitioning dynamics and energetics of a model transmembrane domain from the linker of activation of T cells. We find that partitioning between domains is determined by an interplay between protein-lipid interactions and differential lipid packing between raft and nonraft domains. Specifically, we show that partitioning into ordered domains is promoted by preferential interactions between peptides and ordered lipids, mediated in large part by modification of the peptides by saturated fatty acids (i.e., palmitoylation). Ordered phase affinity is also promoted by elastic effects, specifically hydrophobic matching between the membrane and the peptide. Conversely, ordered domain partitioning is disfavored by the tight molecular packing of the lipids therein. The balance of these dominant drivers determines partitioning. In the case of the wild-type linker of activation of T cells transmembrane domain, these factors combine to yield enrichment of the peptide at Lo/Ld interfaces. These results define some of the general principles governing protein partitioning between coexisting membrane domains and potentially explain previous disparities among experiments and simulations across model systems.
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Affiliation(s)
- Xubo Lin
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, Texas; School of Biological Science and Medical Engineering, Beihang University, Beijing, China; Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing, China
| | - Alemayehu A Gorfe
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, Texas.
| | - Ilya Levental
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, Texas.
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23
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Kamble S, Patil S, Kulkarni M, Murthy AVR. Spectroscopic Ellipsometry of fluid and gel phase lipid bilayers in hydrated conditions. Colloids Surf B Biointerfaces 2019; 176:55-61. [DOI: 10.1016/j.colsurfb.2018.12.061] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 11/20/2018] [Accepted: 12/20/2018] [Indexed: 11/26/2022]
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24
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Han TW, Ye W, Bethel NP, Zubia M, Kim A, Li KH, Burlingame AL, Grabe M, Jan YN, Jan LY. Chemically induced vesiculation as a platform for studying TMEM16F activity. Proc Natl Acad Sci U S A 2019; 116:1309-1318. [PMID: 30622179 PMCID: PMC6347726 DOI: 10.1073/pnas.1817498116] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Calcium-activated phospholipid scramblase mediates the energy-independent bidirectional translocation of lipids across the bilayer, leading to transient or, in the case of apoptotic scrambling, sustained collapse of membrane asymmetry. Cells lacking TMEM16F-dependent lipid scrambling activity are deficient in generation of extracellular vesicles (EVs) that shed from the plasma membrane in a Ca2+-dependent manner, namely microvesicles. We have adapted chemical induction of giant plasma membrane vesicles (GPMVs), which require both TMEM16F-dependent phospholipid scrambling and calcium influx, as a kinetic assay to investigate the mechanism of TMEM16F activity. Using the GPMV assay, we identify and characterize both inactivating and activating mutants that elucidate the mechanism for TMEM16F activation and facilitate further investigation of TMEM16F-mediated lipid translocation and its role in extracellular vesiculation.
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Affiliation(s)
- Tina W Han
- Howard Hughes Medical Institute, University of California, San Francisco, CA 94143
- Department of Physiology, University of California, San Francisco, CA 94143
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94143
| | - Wenlei Ye
- Howard Hughes Medical Institute, University of California, San Francisco, CA 94143
- Department of Physiology, University of California, San Francisco, CA 94143
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94143
| | - Neville P Bethel
- Department of Pharmaceutical Chemistry, Cardiovascular Research Institute, University of California, San Francisco, CA 94143
| | - Mario Zubia
- Howard Hughes Medical Institute, University of California, San Francisco, CA 94143
- Department of Physiology, University of California, San Francisco, CA 94143
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94143
| | - Andrew Kim
- Howard Hughes Medical Institute, University of California, San Francisco, CA 94143
- Department of Physiology, University of California, San Francisco, CA 94143
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94143
| | - Kathy H Li
- Mass Spectrometry Facility, University of California, San Francisco, CA 94143
| | - Alma L Burlingame
- Mass Spectrometry Facility, University of California, San Francisco, CA 94143
| | - Michael Grabe
- Department of Pharmaceutical Chemistry, Cardiovascular Research Institute, University of California, San Francisco, CA 94143
| | - Yuh Nung Jan
- Howard Hughes Medical Institute, University of California, San Francisco, CA 94143
- Department of Physiology, University of California, San Francisco, CA 94143
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94143
| | - Lily Y Jan
- Howard Hughes Medical Institute, University of California, San Francisco, CA 94143;
- Department of Physiology, University of California, San Francisco, CA 94143
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94143
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25
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Lam JGT, Song C, Seveau S. High-throughput Measurement of Plasma Membrane Resealing Efficiency in Mammalian Cells. J Vis Exp 2019. [PMID: 30663635 DOI: 10.3791/58351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
In their physiological environment, mammalian cells are often subjected to mechanical and biochemical stresses that result in plasma membrane damage. In response to these damages, complex molecular machineries rapidly reseal the plasma membrane to restore its barrier function and maintain cell survival. Despite 60 years of research in this field, we still lack a thorough understanding of the cell resealing machinery. With the goal of identifying cellular components that control plasma membrane resealing or drugs that can improve resealing, we have developed a fluorescence-based high-throughput assay that measures the plasma membrane resealing efficiency in mammalian cells cultured in microplates. As a model system for plasma membrane damage, cells are exposed to the bacterial pore-forming toxin listeriolysin O (LLO), which forms large 30-50 nm diameter proteinaceous pores in cholesterol-containing membranes. The use of a temperature-controlled multi-mode microplate reader allows for rapid and sensitive spectrofluorometric measurements in combination with brightfield and fluorescence microscopy imaging of living cells. Kinetic analysis of the fluorescence intensity emitted by a membrane impermeant nucleic acid-binding fluorochrome reflects the extent of membrane wounding and resealing at the cell population level, allowing for the calculation of the cell resealing efficiency. Fluorescence microscopy imaging allows for the enumeration of cells, which constitutively express a fluorescent chimera of the nuclear protein histone 2B, in each well of the microplate to account for potential variations in their number and allows for eventual identification of distinct cell populations. This high-throughput assay is a powerful tool expected to expand our understanding of membrane repair mechanisms via screening for host genes or exogenously added compounds that control plasma membrane resealing.
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Affiliation(s)
- Jonathan G T Lam
- Department of Microbial Infection and Immunity, The Ohio State University; Department of Microbiology, The Ohio State University; Infectious Diseases Institute, The Ohio State University
| | - Chi Song
- Division of Biostatistics, College of Public Health, The Ohio State University
| | - Stephanie Seveau
- Department of Microbial Infection and Immunity, The Ohio State University; Department of Microbiology, The Ohio State University; Infectious Diseases Institute, The Ohio State University;
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26
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Pick H, Alves AC, Vogel H. Single-Vesicle Assays Using Liposomes and Cell-Derived Vesicles: From Modeling Complex Membrane Processes to Synthetic Biology and Biomedical Applications. Chem Rev 2018; 118:8598-8654. [PMID: 30153012 DOI: 10.1021/acs.chemrev.7b00777] [Citation(s) in RCA: 96] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The plasma membrane is of central importance for defining the closed volume of cells in contradistinction to the extracellular environment. The plasma membrane not only serves as a boundary, but it also mediates the exchange of physical and chemical information between the cell and its environment in order to maintain intra- and intercellular functions. Artificial lipid- and cell-derived membrane vesicles have been used as closed-volume containers, representing the simplest cell model systems to study transmembrane processes and intracellular biochemistry. Classical examples are studies of membrane translocation processes in plasma membrane vesicles and proteoliposomes mediated by transport proteins and ion channels. Liposomes and native membrane vesicles are widely used as model membranes for investigating the binding and bilayer insertion of proteins, the structure and function of membrane proteins, the intramembrane composition and distribution of lipids and proteins, and the intermembrane interactions during exo- and endocytosis. In addition, natural cell-released microvesicles have gained importance for early detection of diseases and for their use as nanoreactors and minimal protocells. Yet, in most studies, ensembles of vesicles have been employed. More recently, new micro- and nanotechnological tools as well as novel developments in both optical and electron microscopy have allowed the isolation and investigation of individual (sub)micrometer-sized vesicles. Such single-vesicle experiments have revealed large heterogeneities in the structure and function of membrane components of single vesicles, which were hidden in ensemble studies. These results have opened enormous possibilities for bioanalysis and biotechnological applications involving unprecedented miniaturization at the nanometer and attoliter range. This review will cover important developments toward single-vesicle analysis and the central discoveries made in this exciting field of research.
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Affiliation(s)
- Horst Pick
- Institute of Chemical Sciences and Engineering , Ecole Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne , Switzerland
| | - Ana Catarina Alves
- Institute of Chemical Sciences and Engineering , Ecole Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne , Switzerland
| | - Horst Vogel
- Institute of Chemical Sciences and Engineering , Ecole Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne , Switzerland
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27
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Fülöp G, Brameshuber M, Arnold AM, Schütz GJ, Sevcsik E. Determination of the Membrane Environment of CD59 in Living Cells. Biomolecules 2018; 8:E28. [PMID: 29772810 PMCID: PMC6023084 DOI: 10.3390/biom8020028] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 04/24/2018] [Accepted: 05/14/2018] [Indexed: 11/24/2022] Open
Abstract
The organization and dynamics of proteins and lipids in the plasma membrane, and their role in membrane functionality, have been subject of a long-lasting debate. Specifically, it is unclear to what extent membrane proteins are affected by their immediate lipid environment and vice versa. Studies on model membranes and plasma membrane vesicles indicated preferences of proteins for lipid phases characterized by different acyl chain order; however, whether such phases do indeed exist in live cells is still not known. Here, we refine a previously developed micropatterning approach combined with single molecule tracking to quantify the influence of the glycosylphosphatidylinositol-anchored (GPI-anchored) protein CD59 on its molecular environment directly in the live cell plasma membrane. We find that locally enriched and immobilized CD59 presents obstacles to the diffusion of fluorescently labeled lipids with a different phase-partitioning behavior independent of cell cholesterol levels and type of lipid. Our results give no evidence for either specific binding of the lipids to CD59 or the existence of nanoscopic ordered membrane regions associated with CD59.
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Affiliation(s)
- Gergő Fülöp
- Institute of Applied Physics, TU Wien, Wiedner Hauptstrasse 8-10, Vienna 1040, Austria.
| | - Mario Brameshuber
- Institute of Applied Physics, TU Wien, Wiedner Hauptstrasse 8-10, Vienna 1040, Austria.
| | - Andreas M Arnold
- Institute of Applied Physics, TU Wien, Wiedner Hauptstrasse 8-10, Vienna 1040, Austria.
| | - Gerhard J Schütz
- Institute of Applied Physics, TU Wien, Wiedner Hauptstrasse 8-10, Vienna 1040, Austria.
| | - Eva Sevcsik
- Institute of Applied Physics, TU Wien, Wiedner Hauptstrasse 8-10, Vienna 1040, Austria.
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28
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Raghunathan K, Kenworthy AK. Dynamic pattern generation in cell membranes: Current insights into membrane organization. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:2018-2031. [PMID: 29752898 DOI: 10.1016/j.bbamem.2018.05.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 04/30/2018] [Accepted: 05/03/2018] [Indexed: 12/18/2022]
Abstract
It has been two decades since the lipid raft hypothesis was first presented. Even today, whether these nanoscale cholesterol-rich domains are present in cell membranes is not completely resolved. However, especially in the last few years, a rich body of literature has demonstrated both the presence and the importance of non-random distribution of biomolecules on the membrane, which is the focus of this review. These new developments have pushed the experimental limits of detection and have brought us closer to observing lipid domains in the plasma membrane of live cells. Characterization of biomolecules associated with lipid rafts has revealed a deep connection between biological regulation and function and membrane compositional heterogeneities. Finally, tantalizing new developments in the field have demonstrated that lipid domains might not just be associated with the plasma membrane of eukaryotes but could potentially be a ubiquitous membrane-organizing principle in several other biological systems. This article is part of a Special Issue entitled: Emergence of Complex Behavior in Biomembranes edited by Marjorie Longo.
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Affiliation(s)
- Krishnan Raghunathan
- Department of Pediatrics, Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, PA 15224, USA.
| | - Anne K Kenworthy
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232, USA; Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA.
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29
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Abstract
Helicobacter pylori, a Gram-negative bacterium, is a well-known risk factor for gastric cancer. H. pylori vacuolating cytotoxin A (VacA) is a secreted pore-forming toxin that induces a wide range of cellular responses. Like many other bacterial toxins, VacA has been hypothesized to utilize lipid rafts to gain entry into host cells. Here, we used giant plasma membrane vesicles (GPMVs) as a model system to understand the preferential partitioning of VacA into lipid rafts. We show that a wild-type (WT) toxin predominantly associates with the raft phase. Acid activation of VacA enhances binding of the toxin to GPMVs but is not required for raft partitioning. VacA mutant proteins with alterations at the amino terminus (resulting in impaired membrane channel formation) and a nonoligomerizing VacA mutant protein retain the ability to preferentially associate with lipid rafts. Consistent with these results, the isolated VacA p55 domain was capable of binding to lipid rafts. We conclude that the affinity of VacA for rafts is independent of its capacity to oligomerize or form membrane channels.
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30
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Cholesterol induced asymmetry in DOPC bilayers probed by AFM force spectroscopy. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:953-959. [PMID: 29408513 DOI: 10.1016/j.bbamem.2018.01.021] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 01/24/2018] [Accepted: 01/28/2018] [Indexed: 11/21/2022]
Abstract
Cholesterol induced mechanical effects on artificial lipid bilayers are well known and have been thoroughly investigated by AFM force spectroscopy. However, dynamics of cholesterol impingement into bilayers at various cholesterol concentrations and their effects have not been clearly understood. In this paper we present, the effect of cholesterol as a function of its concentration in a simple single component dioleoylphosphatidylcholine (DOPC) bilayer. The nature of measured breakthrough forces on a bilayer with the addition of cholesterol, suggested that it is not just responsible to increase the mechanical stability but also introduces irregularities across the leaflets of the bilayer. This cholesterol induced asymmetry across the (in the inner and outer leaflets) bilayer is related to the phenomena of interleaflet coupling and is a function of cholesterol concentration probed by AFM can provide an unprecedented direction on mechanical properties of lipid membrane as it can be directly correlated to biophysical properties of a cell membrane.
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31
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Veerapathiran S, Wohland T. The imaging FCS diffusion law in the presence of multiple diffusive modes. Methods 2017; 140-141:140-150. [PMID: 29203404 DOI: 10.1016/j.ymeth.2017.11.016] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 11/24/2017] [Accepted: 11/28/2017] [Indexed: 01/21/2023] Open
Abstract
The cellular plasma membrane is the barrier over which cells exchange materials and communicate with their surroundings, and thus plays the central role in cellular sensing and metabolism. Therefore, the investigation of plasma membrane organization and dynamics is required for understanding of cellular functions. The plasma membrane is a heterogeneous matrix. The presence of structures such as lipid and protein domains and the cytoskeleton meshwork poses a hindrance to the free diffusion of membrane associated biomolecules. However, these domains and the cytoskeleton meshwork barriers are below the optical diffraction limit with potentially short lifetimes and are not easily detected even in super-resolution microscopy. Therefore, dynamic measurements are often used to indirectly prove the existence of domains and barriers by analyzing the mode of diffusion of probe molecules. One of these tools is the Fluorescence Correlation Spectroscopy (FCS) diffusion law. The FCS diffusion law is a plot of diffusion time (τd) versus observation area. For at least three different diffusive modes - free, domain confined, and meshwork hindered hop diffusion - the expected plots have been characterized, typically by its y-intercept (τ0) when fit with a linear model, and have been verified in many cases. However, a description of τ0 has only been given for pure diffusive modes. But in many experimental cases it is not evident that a protein will undergo only one kind of diffusion, and thus the interpretation of the τ0 value is problematic. Here, we therefore address the question about the absolute value of τ0 in the case of complex diffusive modes, i.e. when either one molecule is domain confined and cytoskeleton hindered or when two molecules exhibit different diffusive behavior at the same position in a sample. In addition, we investigate how τ0 changes when the diffusive mode of a probe alters upon disruption of domains or the cytoskeleton by drug treatments. By a combination of experimental studies and simulations, we show that τ0 is not influenced equally by the different diffusive modes as typically found in cellular environments, and that it is the relative change of τ0 rather than its absolute value that provides information on the mode of diffusion.
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Affiliation(s)
- Sapthaswaran Veerapathiran
- Department of Biological Sciences and NUS Centre for Bio-Imaging Sciences, National University of Singapore, 14 Science Drive 4, 117557 Singapore, Singapore
| | - Thorsten Wohland
- Department of Biological Sciences and NUS Centre for Bio-Imaging Sciences, National University of Singapore, 14 Science Drive 4, 117557 Singapore, Singapore; Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543 Singapore, Singapore.
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32
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Levental KR, Surma MA, Skinkle AD, Lorent JH, Zhou Y, Klose C, Chang JT, Hancock JF, Levental I. ω-3 polyunsaturated fatty acids direct differentiation of the membrane phenotype in mesenchymal stem cells to potentiate osteogenesis. SCIENCE ADVANCES 2017; 3:eaao1193. [PMID: 29134198 PMCID: PMC5677358 DOI: 10.1126/sciadv.aao1193] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 10/16/2017] [Indexed: 05/19/2023]
Abstract
Mammalian cells produce hundreds of dynamically regulated lipid species that are actively turned over and trafficked to produce functional membranes. These lipid repertoires are susceptible to perturbations from dietary sources, with potentially profound physiological consequences. However, neither the lipid repertoires of various cellular membranes, their modulation by dietary fats, nor their effects on cellular phenotypes have been widely explored. We report that differentiation of human mesenchymal stem cells (MSCs) into osteoblasts or adipocytes results in extensive remodeling of the plasma membrane (PM), producing cell-specific membrane compositions and biophysical properties. The distinct features of osteoblast PMs enabled rational engineering of membrane phenotypes to modulate differentiation in MSCs. Specifically, supplementation with docosahexaenoic acid (DHA), a lipid component characteristic of osteoblast membranes, induced broad lipidomic remodeling in MSCs that reproduced compositional and structural aspects of the osteoblastic PM phenotype. The PM changes induced by DHA supplementation potentiated osteogenic differentiation of MSCs concurrent with enhanced Akt activation at the PM. These observations prompt a model wherein the DHA-induced lipidome leads to more stable membrane microdomains, which serve to increase Akt activity and thereby enhance osteogenic differentiation. More broadly, our investigations suggest a general mechanism by which dietary fats affect cellular physiology through remodeling of membrane lipidomes, biophysical properties, and signaling.
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Affiliation(s)
- Kandice R. Levental
- McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | | | | | - Joseph H. Lorent
- McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Yong Zhou
- McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | | | - Jeffrey T. Chang
- McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
- School of Biomedical Informatics, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
- Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
- Department of Bioinformatics and Computational Biology, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - John F. Hancock
- McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
- Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Ilya Levental
- McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
- Corresponding author.
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33
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Peng R, Wang H, Lyu Y, Xu L, Liu H, Kuai H, Liu Q, Tan W. Facile Assembly/Disassembly of DNA Nanostructures Anchored on Cell-Mimicking Giant Vesicles. J Am Chem Soc 2017; 139:12410-12413. [PMID: 28841373 PMCID: PMC5877790 DOI: 10.1021/jacs.7b07485] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
DNA nanostructures assembled on living cell membranes have become powerful research tools. Synthetic lipid membranes have been used as a membrane model to study the dynamic behavior of DNA nanostructures on fluid soft lipid bilayers, but without the inherent complexity of natural membranes. Herein, we report the assembly and disassembly of DNA nanoprisms on cell-mimicking micrometer-scale giant membrane vesicles derived from living mammalian cells. Three-dimensional DNA nanoprisms with a DNA arm and a cholesterol anchor were efficiently localized on the membrane surface. The assembly and disassembly of DNA nanoprisms were dynamically manipulated by DNA strand hybridization and toehold-mediated strand displacement. Furthermore, the heterogeneity of reversible assembly/disassembly of DNA nanoprisms was monitored by Förster resonance energy transfer. This study suggests the feasibility of DNA-mediated functional biomolecular assembly on cell membranes for biomimetics studies and delivery systems.
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Affiliation(s)
- Ruizi Peng
- Molecular Science and Biomedicine Laboratory, State Key Laboratory of Chemo/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering, College of Life Sciences, and Aptamer Engineering Center of Hunan Province, Hunan University, Changsha, Hunan 410082, China
| | - Huijing Wang
- Molecular Science and Biomedicine Laboratory, State Key Laboratory of Chemo/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering, College of Life Sciences, and Aptamer Engineering Center of Hunan Province, Hunan University, Changsha, Hunan 410082, China
| | - Yifan Lyu
- Molecular Science and Biomedicine Laboratory, State Key Laboratory of Chemo/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering, College of Life Sciences, and Aptamer Engineering Center of Hunan Province, Hunan University, Changsha, Hunan 410082, China
- Department of Chemistry and Department of Physiology and Functional Genomics, Center for Research at the Bio/Nano Interface, Health Cancer Center, UF Genetics Institute, McKnight Brain Institute, University of Florida, Gainesville, Florida 32611-7200, United States
| | - Liujun Xu
- Molecular Science and Biomedicine Laboratory, State Key Laboratory of Chemo/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering, College of Life Sciences, and Aptamer Engineering Center of Hunan Province, Hunan University, Changsha, Hunan 410082, China
| | - Hui Liu
- Molecular Science and Biomedicine Laboratory, State Key Laboratory of Chemo/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering, College of Life Sciences, and Aptamer Engineering Center of Hunan Province, Hunan University, Changsha, Hunan 410082, China
| | - Hailan Kuai
- Molecular Science and Biomedicine Laboratory, State Key Laboratory of Chemo/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering, College of Life Sciences, and Aptamer Engineering Center of Hunan Province, Hunan University, Changsha, Hunan 410082, China
| | - Qiaoling Liu
- Molecular Science and Biomedicine Laboratory, State Key Laboratory of Chemo/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering, College of Life Sciences, and Aptamer Engineering Center of Hunan Province, Hunan University, Changsha, Hunan 410082, China
| | - Weihong Tan
- Molecular Science and Biomedicine Laboratory, State Key Laboratory of Chemo/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering, College of Life Sciences, and Aptamer Engineering Center of Hunan Province, Hunan University, Changsha, Hunan 410082, China
- Department of Chemistry and Department of Physiology and Functional Genomics, Center for Research at the Bio/Nano Interface, Health Cancer Center, UF Genetics Institute, McKnight Brain Institute, University of Florida, Gainesville, Florida 32611-7200, United States
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34
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Haralampiev I, Scheidt HA, Huster D, Müller P. The Potential of α-Spinasterol to Mimic the Membrane Properties of Natural Cholesterol. Molecules 2017; 22:molecules22081390. [PMID: 28829376 PMCID: PMC6152097 DOI: 10.3390/molecules22081390] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 08/18/2017] [Accepted: 08/19/2017] [Indexed: 01/07/2023] Open
Abstract
Sterols play a unique role for the structural and dynamical organization of membranes. The current study reports data on the membrane properties of the phytosterol (3β,5α,22E)-stigmasta-7,22-dien-3-β-ol (α-spinasterol), which represents an important component of argan oil and have not been investigated so far in molecular detail. In particular, the impact of α-spinasterol on the structure and organization of lipid membranes was investigated and compared with those of cholesterol. Various membrane parameters such as the molecular packing of the phospholipid fatty acyl chains, the membrane permeability toward polar molecules, and the formation of lateral membrane domains were studied. The experiments were performed on lipid vesicles using methods of NMR spectroscopy and fluorescence spectroscopy and microscopy. The results show that α-spinasterol resembles the membrane behavior of cholesterol to some degree.
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Affiliation(s)
- Ivan Haralampiev
- Department of Biology, Humboldt-Universität zu Berlin, Invalidenstr. 42, D-10115 Berlin, Germany.
| | - Holger A Scheidt
- Institute for Medical Physics and Biophysics, Leipzig University, Härtelstr. 16-18, D-04107 Leipzig, Germany.
| | - Daniel Huster
- Institute for Medical Physics and Biophysics, Leipzig University, Härtelstr. 16-18, D-04107 Leipzig, Germany.
| | - Peter Müller
- Department of Biology, Humboldt-Universität zu Berlin, Invalidenstr. 42, D-10115 Berlin, Germany.
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35
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Sezgin E. Super-resolution optical microscopy for studying membrane structure and dynamics. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:273001. [PMID: 28481213 PMCID: PMC5952331 DOI: 10.1088/1361-648x/aa7185] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Investigation of cell membrane structure and dynamics requires high spatial and temporal resolution. The spatial resolution of conventional light microscopy is limited due to the diffraction of light. However, recent developments in microscopy enabled us to access the nano-scale regime spatially, thus to elucidate the nanoscopic structures in the cellular membranes. In this review, we will explain the resolution limit, address the working principles of the most commonly used super-resolution microscopy techniques and summarise their recent applications in the biomembrane field.
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Affiliation(s)
- Erdinc Sezgin
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, OX39DS, United Kingdom
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36
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Polyunsaturated Lipids Regulate Membrane Domain Stability by Tuning Membrane Order. Biophys J 2017; 110:1800-1810. [PMID: 27119640 DOI: 10.1016/j.bpj.2016.03.012] [Citation(s) in RCA: 136] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Revised: 03/08/2016] [Accepted: 03/09/2016] [Indexed: 11/21/2022] Open
Abstract
The plasma membrane (PM) serves as the functional interface between a cell and its environment, hosting extracellular signal transduction and nutrient transport among a variety of other processes. To support this extensive functionality, PMs are organized into lateral domains, including ordered, lipid-driven assemblies termed lipid rafts. Although the general requirements for ordered domain formation are well established, how these domains are regulated by cell-endogenous mechanisms or exogenous perturbations has not been widely addressed. In this context, an intriguing possibility is that dietary fats can incorporate into membrane lipids to regulate the properties and physiology of raft domains. Here, we investigate the effects of polyunsaturated fats on the organization of membrane domains across a spectrum of membrane models, including computer simulations, synthetic lipid membranes, and intact PMs isolated from mammalian cells. We observe that the ω-3 polyunsaturated fatty acid docosahexaenoic acid is robustly incorporated into membrane lipids, and this incorporation leads to significant remodeling of the PM lipidome. Across model systems, docosahexaenoic acid-containing lipids enhance the stability of ordered raft domains by increasing the order difference between them and coexisting nonraft domains. The relationship between interdomain order disparity and the stability of phase separation holds for a spectrum of different perturbations, including manipulation of cholesterol levels and high concentrations of exogenous amphiphiles, suggesting it as a general feature of the organization of biological membranes. These results demonstrate that polyunsaturated fats affect the composition and organization of biological membranes, suggesting a potential mechanism for the extensive effects of dietary fat on health and disease.
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37
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Edler E, Schulze E, Stein M. Membrane localization and dynamics of geranylgeranylated Rab5 hypervariable region. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1859:1335-1349. [PMID: 28455099 DOI: 10.1016/j.bbamem.2017.04.021] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Revised: 04/18/2017] [Accepted: 04/23/2017] [Indexed: 12/11/2022]
Abstract
The small GTPase Rab5 is a key regulator of endosomal trafficking processes and a marker for the early endosome. The C-terminal hypervariable region (HVR) of Rab5 is post-translationally modified at residues Cys212 and Cys213 to accommodate two geranylgeranyl anchors (C20 carbon chain length) in order to associate Rab5 with the membrane. The structural role of the HVR regarding protein-early endosome membrane recruitment is not resolved due to its high degree of flexibility and lack of crystallographic information. Here, full-atomistic and coarse-grained molecular dynamics simulations of the truncated Rab5 HVR206-215 in three model membranes of increasing complexity (pure phospholipid bilayer, ternary membrane with cholesterol, six-component early endosome) were performed. Specific electrostatic interactions between the HVR206-215 Arg209 residue and the phosphate group of the inositol ring of PI(3)P were detected. This shows that PI(3)P acts as a first contact site of protein recruitment to the early endosome. The free energy change of HVR206-215 extraction from the bilayer was largest for the physiological negatively charged membrane. 5μs coarse-grained simulations revealed an active recruitment of PI(3)P to the HVR206-215 supporting the formation of Rab5- and PI(3)P enriched signaling platforms.
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Affiliation(s)
- Eileen Edler
- Molecular Simulations and Design Group, Max Planck Institute for Dynamics of Complex Technical Systems, Sandtorstrasse 1, 39106 Magdeburg, Germany
| | - Eric Schulze
- Molecular Simulations and Design Group, Max Planck Institute for Dynamics of Complex Technical Systems, Sandtorstrasse 1, 39106 Magdeburg, Germany; International Max Planck Research School (IMPRS) for Advanced Methods in Process and Systems Engineering, Magdeburg, Germany
| | - Matthias Stein
- Molecular Simulations and Design Group, Max Planck Institute for Dynamics of Complex Technical Systems, Sandtorstrasse 1, 39106 Magdeburg, Germany.
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38
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Huang S, Lim SY, Gupta A, Bag N, Wohland T. Plasma membrane organization and dynamics is probe and cell line dependent. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1859:1483-1492. [PMID: 27998689 DOI: 10.1016/j.bbamem.2016.12.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Revised: 12/03/2016] [Accepted: 12/08/2016] [Indexed: 01/01/2023]
Abstract
The action and interaction of membrane receptor proteins take place within the plasma membrane. The plasma membrane, however, is not a passive matrix. It rather takes an active role and regulates receptor distribution and function by its composition and the interaction of its lipid components with embedded and surrounding proteins. Furthermore, it is not a homogenous fluid but contains lipid and protein domains of various sizes and characteristic lifetimes which are important in regulating receptor function and signaling. The precise lateral organization of the plasma membrane, the differences between the inner and outer leaflet, and the influence of the cytoskeleton are still debated. Furthermore, there is a lack of comparisons of the organization and dynamics of the plasma membrane of different cell types. Therefore, we used four different specific membrane markers to test the lateral organization, the differences between the inner and outer membrane leaflet, and the influence of the cytoskeleton of up to five different cell lines, including Chinese hamster ovary (CHO-K1), Human cervical carcinoma (HeLa), neuroblastoma (SH-SY5Y), fibroblast (WI-38) and rat basophilic leukemia (RBL-2H3) cells by Imaging Total Internal Reflection (ITIR)-Fluorescence Correlation Spectroscopy (FCS). We measure diffusion in the temperature range of 298-310K to measure the Arrhenius activation energy (EArr) of diffusion and apply the FCS diffusion law to obtain information on the spatial organization of the probe molecules on the various cell membranes. Our results show clear differences of the FCS diffusion law and EArr for the different probes in dependence of their localization. These differences are similar in the outer and inner leaflet of the membrane. However, these values can differ significantly between different cell lines raising the question how molecular plasma membrane events measured in different cell lines can be compared. This article is part of a Special Issue entitled: Interactions between membrane receptors in cellular membranes edited by Kalina Hristova.
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Affiliation(s)
- Shuangru Huang
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore; NUS Centre for Bio-Imaging Sciences, National University of Singapore, 14 Science Drive 4, Singapore
| | - Shi Ying Lim
- NUS Centre for Bio-Imaging Sciences, National University of Singapore, 14 Science Drive 4, Singapore; Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore
| | - Anjali Gupta
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore; NUS Centre for Bio-Imaging Sciences, National University of Singapore, 14 Science Drive 4, Singapore
| | - Nirmalya Bag
- NUS Centre for Bio-Imaging Sciences, National University of Singapore, 14 Science Drive 4, Singapore; Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore
| | - Thorsten Wohland
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore; NUS Centre for Bio-Imaging Sciences, National University of Singapore, 14 Science Drive 4, Singapore; Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore.
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39
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Raghunathan K, Wong TH, Chinnapen DJ, Lencer WI, Jobling MG, Kenworthy AK. Glycolipid Crosslinking Is Required for Cholera Toxin to Partition Into and Stabilize Ordered Domains. Biophys J 2016; 111:2547-2550. [PMID: 27914621 DOI: 10.1016/j.bpj.2016.11.008] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Revised: 11/09/2016] [Accepted: 11/11/2016] [Indexed: 12/17/2022] Open
Abstract
Current models of lipid rafts propose that lipid domains exist as nanoscale compositional fluctuations and these fluctuations can potentially be stabilized into larger domains, consequently better compartmentalizing cellular functions. However, the mechanisms governing stabilized raft assembly and function remain unclear. Here, we test the role of glycolipid crosslinking as a raft targeting and ordering mechanism using the well-studied raft marker cholera toxin B pentamer (CTxB) that binds up to five GM1 glycosphingolipids to enter host cells. We show that when applied to cell-derived giant plasma membrane vesicles, a variant of CTxB containing only a single functional GM1 binding site exhibits significantly reduced partitioning to the ordered phase compared to wild-type CTxB with five binding sites. Moreover, monovalent CTxB does not stabilize membrane domains, unlike wild-type CTxB. These results support the long-held hypothesis that CTxB stabilizes raft domains via a lipid crosslinking mechanism and establish a role for crosslinking in the partitioning of CTxB to ordered domains.
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Affiliation(s)
- Krishnan Raghunathan
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Tiffany H Wong
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Daniel J Chinnapen
- Harvard Medical School and the Harvard Digestive Diseases Center, Boston, Massachusetts
| | - Wayne I Lencer
- Harvard Medical School and the Harvard Digestive Diseases Center, Boston, Massachusetts
| | - Michael G Jobling
- Department of Immunology and Microbiology, University of Colorado, Aurora, Colorado
| | - Anne K Kenworthy
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee; Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, Tennessee.
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40
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Johnson RG, Le HC, Evenson K, Loberg SW, Myslajek TM, Prabhu A, Manley AM, O’Shea C, Grunenwald H, Haddican M, Fitzgerald PM, Robinson T, Cisterna BA, Sáez JC, Liu TF, Laird DW, Sheridan JD. Connexin Hemichannels: Methods for Dye Uptake and Leakage. J Membr Biol 2016; 249:713-741. [DOI: 10.1007/s00232-016-9925-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 08/22/2016] [Indexed: 01/18/2023]
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41
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Levental I, Veatch S. The Continuing Mystery of Lipid Rafts. J Mol Biol 2016; 428:4749-4764. [PMID: 27575334 DOI: 10.1016/j.jmb.2016.08.022] [Citation(s) in RCA: 192] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 08/16/2016] [Accepted: 08/19/2016] [Indexed: 12/12/2022]
Abstract
Since its initial formalization nearly 20 years ago, the concept of lipid rafts has generated a tremendous amount of attention and interest and nearly as much controversy. The controversy is perhaps surprising because the notion itself is intuitive: compartmentalization in time and space is a ubiquitous theme at all scales of biology, and therefore, the partitioning of cellular membranes into lateral subdivision should be expected. Nevertheless, the physicochemical principles responsible for compartmentalization and the molecular mechanisms by which they are functionalized remain nearly as mysterious today as they were two decades ago. Herein, we review recent literature on this topic with a specific focus on the major open questions in the field including: (1) what are the best tools to assay raft behavior in living membranes? (2) what is the function of the complex lipidome of mammalian cells with respect to membrane organization? (3) what are the mechanisms that drive raft formation and determine their properties? (4) how can rafts be modulated? (5) how is membrane compartmentalization integrated into cellular signaling? Despite decades of intensive research, this compelling field remains full of fundamental questions.
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Affiliation(s)
- Ilya Levental
- McGovern Medical School at the University of Texas Houston, Department of Integrative Biology and Pharmacology
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42
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Moens PDJ, Digman MA, Gratton E. Modes of diffusion of cholera toxin bound to GM1 on live cell membrane by image mean square displacement analysis. Biophys J 2016; 108:1448-1458. [PMID: 25809257 DOI: 10.1016/j.bpj.2015.02.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Revised: 01/27/2015] [Accepted: 02/02/2015] [Indexed: 11/16/2022] Open
Abstract
The image-mean square displacement technique applies the calculation of the mean square displacement commonly used in single-molecule tracking to images without resolving single particles. The image-mean square displacement plot obtained is similar to the mean square displacement plot obtained using the single-particle tracking technique. This plot is then used to reconstruct the protein diffusion law and to identify whether the labeled molecules are undergoing pure isotropic, restricted, corralled, transiently confined, or directed diffusion. In our study total internal reflection fluorescence microscopy images were taken of Cholera toxin subunit B (CtxB) membrane-labeled NIH 3T3 mouse fibroblasts and MDA 231 MB cells. We found a population of CTxB undergoing purely isotropic diffusion and one displaying restricted diffusion with corral sizes ranging from 150 to ∼1800 nm. We show that the diffusion rate of CTxB bound to GM1 is independent of the size of the confinement, suggesting that the mechanism of confinement is different from the mechanism controlling the diffusion rate of CtxB. We highlight the potential effect of continuous illumination on the diffusion mode of CTxB. We also show that aggregation of CTxB/GM1 in large complexes occurs and that these aggregates tend to have slower diffusion rates.
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Affiliation(s)
- Pierre D J Moens
- Centre for Bioactive Discovery in Health and Ageing, School of Science and Technology, University of New England, Armidale, Australia.
| | - Michelle A Digman
- Centre for Bioactive Discovery in Health and Ageing, School of Science and Technology, University of New England, Armidale, Australia; Laboratory for Fluorescence Dynamics, Department of Biomedical Engineering, University of California, Irvine, Irvine, California
| | - Enrico Gratton
- Centre for Bioactive Discovery in Health and Ageing, School of Science and Technology, University of New England, Armidale, Australia; Laboratory for Fluorescence Dynamics, Department of Biomedical Engineering, University of California, Irvine, Irvine, California
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43
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Oyama K, Arai T, Isaka A, Sekiguchi T, Itoh H, Seto Y, Miyazaki M, Itabashi T, Ohki T, Suzuki M, Ishiwata S. Directional bleb formation in spherical cells under temperature gradient. Biophys J 2016. [PMID: 26200871 DOI: 10.1016/j.bpj.2015.06.016] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Living cells sense absolute temperature and temporal changes in temperature using biological thermosensors such as ion channels. Here, we reveal, to our knowledge, a novel mechanism of sensing spatial temperature gradients within single cells. Spherical mitotic cells form directional membrane extensions (polar blebs) under sharp temperature gradients (≥∼0.065°C μm(-1); 1.3°C temperature difference within a cell), which are created by local heating with a focused 1455-nm laser beam under an optical microscope. On the other hand, multiple nondirectional blebs are formed under gradual temperature gradients or uniform heating. During heating, the distribution of actomyosin complexes becomes inhomogeneous due to a break in the symmetry of its contractile force, highlighting the role of the actomyosin complex as a sensor of local temperature gradients.
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Affiliation(s)
- Kotaro Oyama
- Department of Physics, School of Advanced Science and Engineering, Waseda University, Tokyo, Japan.
| | - Tomomi Arai
- Department of Physics, School of Advanced Science and Engineering, Waseda University, Tokyo, Japan
| | - Akira Isaka
- Department of Physics, School of Advanced Science and Engineering, Waseda University, Tokyo, Japan
| | - Taku Sekiguchi
- Department of Physics, School of Advanced Science and Engineering, Waseda University, Tokyo, Japan
| | - Hideki Itoh
- Department of Physics, School of Advanced Science and Engineering, Waseda University, Tokyo, Japan; Institute of Medical Biology, Agency for Science, Technology and Research (A(∗)STAR), Singapore, Singapore
| | - Yusuke Seto
- Department of Physics, School of Advanced Science and Engineering, Waseda University, Tokyo, Japan
| | - Makito Miyazaki
- Department of Physics, School of Advanced Science and Engineering, Waseda University, Tokyo, Japan
| | - Takeshi Itabashi
- Department of Physics, School of Advanced Science and Engineering, Waseda University, Tokyo, Japan
| | - Takashi Ohki
- Department of Physics, School of Advanced Science and Engineering, Waseda University, Tokyo, Japan
| | - Madoka Suzuki
- WASEDA Bioscience Research Institute in Singapore (WABIOS), Singapore, Singapore; Organization for University Research Initiatives, Waseda University, Tokyo, Japan.
| | - Shin'ichi Ishiwata
- Department of Physics, School of Advanced Science and Engineering, Waseda University, Tokyo, Japan; WASEDA Bioscience Research Institute in Singapore (WABIOS), Singapore, Singapore; Organization for University Research Initiatives, Waseda University, Tokyo, Japan.
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44
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Chlanda P, Zimmerberg J. Protein-lipid interactions critical to replication of the influenza A virus. FEBS Lett 2016; 590:1940-54. [PMID: 26921878 DOI: 10.1002/1873-3468.12118] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 02/08/2016] [Accepted: 02/21/2016] [Indexed: 12/12/2022]
Abstract
Influenza A virus (IAV) assembles on the plasma membrane where viral proteins localize to form a bud encompassing the viral genome, which ultimately pinches off to give rise to newly formed infectious virions. Upon entry, the virus faces the opposite task-fusion with the endosomal membrane and disassembly to deliver the viral genome to the cytoplasm. There are at least four influenza proteins-hemagglutinin (HA), neuraminidase (NA), matrix 1 protein (M1), and the M2 ion channel-that are known to directly interact with the cellular membrane and modify membrane curvature in order to both assemble and disassemble membrane-enveloped virions. Here, we summarize and discuss current knowledge of the interactions of lipids and membrane proteins involved in the IAV replication cycle.
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Affiliation(s)
- Petr Chlanda
- Section on Integrative Biophysics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Joshua Zimmerberg
- Section on Integrative Biophysics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
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45
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Imaging approaches for analysis of cholesterol distribution and dynamics in the plasma membrane. Chem Phys Lipids 2016; 199:106-135. [PMID: 27016337 DOI: 10.1016/j.chemphyslip.2016.03.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Accepted: 03/04/2016] [Indexed: 11/21/2022]
Abstract
Cholesterol is an important lipid component of the plasma membrane (PM) of mammalian cells, where it is involved in control of many physiological processes, such as endocytosis, cell migration, cell signalling and surface ruffling. In an attempt to explain these functions of cholesterol, several models have been put forward about cholesterol's lateral and transbilayer organization in the PM. In this article, we review imaging techniques developed over the last two decades for assessing the distribution and dynamics of cholesterol in the PM of mammalian cells. Particular focus is on fluorescence techniques to study the lateral and inter-leaflet distribution of suitable cholesterol analogues in the PM of living cells. We describe also several methods for determining lateral cholesterol dynamics in the PM including fluorescence recovery after photobleaching (FRAP), fluorescence correlation spectroscopy (FCS), single particle tracking (SPT) and spot variation FCS coupled to stimulated emission depletion (STED) microscopy. For proper interpretation of such measurements, we provide some background in probe photophysics and diffusion phenomena occurring in cell membranes. In particular, we show the equivalence of the reaction-diffusion approach, as used in FRAP and FCS, and continuous time random walk (CTRW) models, as often invoked in SPT studies. We also discuss mass spectrometry (MS) based imaging of cholesterol in the PM of fixed cells and compare this method with fluorescence imaging of sterols. We conclude that evidence from many experimental techniques converges towards a model of a homogeneous distribution of cholesterol with largely free and unhindered diffusion in both leaflets of the PM.
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46
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Bleecker JV, Cox PA, Foster RN, Litz JP, Blosser MC, Castner DG, Keller SL. Thickness Mismatch of Coexisting Liquid Phases in Noncanonical Lipid Bilayers. J Phys Chem B 2016; 120:2761-70. [PMID: 26890258 DOI: 10.1021/acs.jpcb.5b10165] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Lipid composition dictates membrane thickness, which in turn can influence membrane protein activity. Lipid composition also determines whether a membrane demixes into coexisting liquid-crystalline phases. Previous direct measurements of demixed lipid membranes have always found a liquid-ordered phase that is thicker than the liquid-disordered phase. Here we investigated noncanonical ternary lipid mixtures designed to produce bilayers with thicker disordered phases than ordered phases. The membranes were composed of short, saturated (ordered) lipids; long, unsaturated (disordered) lipids; and cholesterol. We found that few of these systems yield coexisting liquid phases above 10 °C. For membranes that do demix into two liquid phases, we measured the thickness mismatch between the phases by atomic force microscopy and found that not one of the systems yields thicker disordered than ordered phases under standard experimental conditions. We found no monotonic relationship between demixing temperatures of these ternary systems and either estimated thickness mismatches between the liquid phases or the physical parameters of single-component membranes composed of the individual lipids. These results highlight the robustness of a membrane's liquid-ordered phase to be thicker than the liquid-disordered phase, regardless of the membrane's lipid composition.
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Affiliation(s)
- Joan V Bleecker
- Departments of Chemistry, ‡Chemical Engineering, and §Bioengineering, University of Washington , Seattle, Washington 98195, United States
| | - Phillip A Cox
- Departments of Chemistry, ‡Chemical Engineering, and §Bioengineering, University of Washington , Seattle, Washington 98195, United States
| | - Rami N Foster
- Departments of Chemistry, ‡Chemical Engineering, and §Bioengineering, University of Washington , Seattle, Washington 98195, United States
| | - Jonathan P Litz
- Departments of Chemistry, ‡Chemical Engineering, and §Bioengineering, University of Washington , Seattle, Washington 98195, United States
| | - Matthew C Blosser
- Departments of Chemistry, ‡Chemical Engineering, and §Bioengineering, University of Washington , Seattle, Washington 98195, United States
| | - David G Castner
- Departments of Chemistry, ‡Chemical Engineering, and §Bioengineering, University of Washington , Seattle, Washington 98195, United States
| | - Sarah L Keller
- Departments of Chemistry, ‡Chemical Engineering, and §Bioengineering, University of Washington , Seattle, Washington 98195, United States
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47
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Podkalicka J, Biernatowska A, Majkowski M, Grzybek M, Sikorski AF. MPP1 as a Factor Regulating Phase Separation in Giant Plasma Membrane-Derived Vesicles. Biophys J 2016; 108:2201-11. [PMID: 25954878 PMCID: PMC4423064 DOI: 10.1016/j.bpj.2015.03.017] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Revised: 02/26/2015] [Accepted: 03/10/2015] [Indexed: 12/15/2022] Open
Abstract
The existence of membrane-rafts helps to conceptually understand the spatiotemporal organization of membrane-associated events (signaling, fusion, fission, etc.). However, as rafts themselves are nanoscopic, dynamic, and transient assemblies, they cannot be directly observed in a metabolizing cell by traditional microscopy. The observation of phase separation in giant plasma membrane-derived vesicles from live cells is a powerful tool for studying lateral heterogeneity in eukaryotic cell membranes, specifically in the context of membrane rafts. Microscopic phase separation is detectable by fluorescent labeling, followed by cooling of the membranes below their miscibility phase transition temperature. It remains unclear, however, if this lipid-driven process is tuneable in any way by interactions with proteins. Here, we demonstrate that MPP1, a member of the MAGUK family, can modulate membrane properties such as the fluidity and phase separation capability of giant plasma membrane-derived vesicles. Our data suggest that physicochemical domain properties of the membrane can be modulated, without major changes in lipid composition, through proteins such as MPP1.
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Affiliation(s)
- Joanna Podkalicka
- Laboratory of Cytobiochemistry, Faculty of Biotechnology, University of Wrocław, Wrocław, Poland; Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Agnieszka Biernatowska
- Laboratory of Cytobiochemistry, Faculty of Biotechnology, University of Wrocław, Wrocław, Poland
| | - Michał Majkowski
- Laboratory of Cytobiochemistry, Faculty of Biotechnology, University of Wrocław, Wrocław, Poland
| | - Michał Grzybek
- Paul Langerhans Institute Dresden of the Helmholtz Centre Munich at the University Clinic Carl Gustav Carus, TU Dresden, Dresden, Germany; German Center for Diabetes Research (DZD e.v.), Neuherberg, Germany
| | - Aleksander F Sikorski
- Laboratory of Cytobiochemistry, Faculty of Biotechnology, University of Wrocław, Wrocław, Poland.
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48
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In situ quantification of protein binding to the plasma membrane. Biophys J 2016; 108:2648-57. [PMID: 26039166 DOI: 10.1016/j.bpj.2015.04.021] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Revised: 03/24/2015] [Accepted: 04/20/2015] [Indexed: 11/21/2022] Open
Abstract
This study presents a fluorescence-based assay that allows for direct measurement of protein binding to the plasma membrane inside living cells. An axial scan through the cell generates a fluorescence intensity profile that is analyzed to determine the membrane-bound and cytoplasmic concentrations of a peripheral membrane protein labeled by the enhanced green fluorescent protein (EGFP). The membrane binding curve is constructed by mapping those concentrations for a population of cells with a wide range of protein expression levels, and a fit of the binding curve determines the number of binding sites and the dissociation coefficient. We experimentally verified the technique, using myosin-1C-EGFP as a model system and fit its binding curve. Furthermore, we studied the protein-lipid interactions of the membrane binding domains from lactadherin and phospholipase C-δ1 to evaluate the feasibility of using competition binding experiments to identify specific lipid-protein interactions in living cells. Finally, we applied the technique to determine the lipid specificity, the number of binding sites, and the dissociation coefficient of membrane binding for the Gag matrix domain of human T-lymphotropic virus type 1, which provides insight into early assembly steps of the retrovirus.
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49
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Abstract
The fundamental mechanisms of protein and lipid organization at the plasma membrane have continued to engage researchers for decades. Among proposed models, one idea has been particularly successful which assumes that sterol-dependent nanoscopic phases of different lipid chain order compartmentalize proteins, thereby modulating protein functionality. This model of membrane rafts has sustainably sparked the fields of membrane biophysics and biology, and shifted membrane lipids into the spotlight of research; by now, rafts have become an integral part of our terminology to describe a variety of cell biological processes. But is the evidence clear enough to continue supporting a theoretical concept which has resisted direct proof by observation for nearly twenty years? In this essay, we revisit findings that gave rise to and substantiated the raft hypothesis, discuss its impact on recent studies, and present alternative mechanisms to account for plasma membrane heterogeneity.
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Affiliation(s)
- Eva Sevcsik
- Institute of Applied Physics, Vienna University of Technology, Vienna, Austria
| | - Gerhard J Schütz
- Institute of Applied Physics, Vienna University of Technology, Vienna, Austria
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50
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Vagne Q, Turner MS, Sens P. Sensing Size through Clustering in Non-Equilibrium Membranes and the Control of Membrane-Bound Enzymatic Reactions. PLoS One 2015; 10:e0143470. [PMID: 26656912 PMCID: PMC4687633 DOI: 10.1371/journal.pone.0143470] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 11/05/2015] [Indexed: 11/18/2022] Open
Abstract
The formation of dynamical clusters of proteins is ubiquitous in cellular membranes and is in part regulated by the recycling of membrane components. We show, using stochastic simulations and analytic modeling, that the out-of-equilibrium cluster size distribution of membrane components undergoing continuous recycling is strongly influenced by lateral confinement. This result has significant implications for the clustering of plasma membrane proteins whose mobility is hindered by cytoskeletal “corrals” and for protein clustering in cellular organelles of limited size that generically support material fluxes. We show how the confinement size can be sensed through its effect on the size distribution of clusters of membrane heterogeneities and propose that this could be regulated to control the efficiency of membrane-bound reactions. To illustrate this, we study a chain of enzymatic reactions sensitive to membrane protein clustering. The reaction efficiency is found to be a non-monotonic function of the system size, and can be optimal for sizes comparable to those of cellular organelles.
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Affiliation(s)
- Quentin Vagne
- Institut Curie, PSL Research University, CNRS, UMR 168, 26 rue d’Ulm, F-75005, Paris, France
| | - Matthew S. Turner
- Dept. of Physics & Complexity Centre, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Pierre Sens
- Institut Curie, PSL Research University, CNRS, UMR 168, 26 rue d’Ulm, F-75005, Paris, France
- * E-mail:
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