1
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Paratore TA, Schmidt GE, Ross AH, Gericke A. Thermal Stability of bivalent cation/phosphoinositide domains in model membranes. Chem Phys Lipids 2024:105424. [PMID: 39098579 DOI: 10.1016/j.chemphyslip.2024.105424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2024] [Revised: 07/30/2024] [Accepted: 07/31/2024] [Indexed: 08/06/2024]
Abstract
As key mediators in a wide array of signaling events, phosphoinositides (PIPs) orchestrate the recruitment of proteins to specific cellular locations at precise moments. This intricate spatiotemporal regulation of protein activity often necessitates the localized enrichment of the corresponding PIP. We investigate the extent and thermal stabilities of phosphatidylinositol-4-phosphate (PI(4)P), phosphatidylinositol-4,5-bisphosphate (PI(4,5)P2 and phosphatidylinositol-3,4,5-trisphosphate (PI(3,4,5)P3) clusters with calcium and magnesium ions. We observe negligible or minimal clustering of all examined PIPs in the presence of Mg2+ ions. While PI(4)P shows in the presence of Ca2+ no clustering, PI(4,5)P2 forms with Ca2+ strong clusters that exhibit stablity up to at least 80°C. The extent of cluster formation for the interaction of PI(3,4,5)P3 with Ca2+ is less than what was observed for PI(4,5)P2, yet we still observe some clustering up to 80°C. Given that cholesterol has been demonstrated to enhance PIP clustering, we examined whether bivalent cations and cholesterol synergistically promote PIP clustering. We found that the interaction of Mg2+ or Ca2+ with PI(4)P remains extraordinarily weak, even in the presence of cholesterol. In contrast, we observe synergistic interaction of cholesterol and Ca2+ with PI(4,5)P2. Also, in the presence of cholesterol, the interaction of Mg2+ with PI(4,5)P2 remains weak. PI(3,4,5)P3 does not show strong clustering with cholesterol for the experimental conditions of our study and the interaction with Ca2+ and Mg2+ was not influenced by the presence of cholesterol.
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Affiliation(s)
- Trevor A Paratore
- Worcester Polytechnic Institute, Department of Chemistry and Biochemistry, Worcester, MA, 01609, USA
| | - Greta E Schmidt
- Worcester Polytechnic Institute, Department of Chemistry and Biochemistry, Worcester, MA, 01609, USA
| | - Alonzo H Ross
- Worcester Polytechnic Institute, Department of Chemistry and Biochemistry, Worcester, MA, 01609, USA
| | - Arne Gericke
- Worcester Polytechnic Institute, Department of Chemistry and Biochemistry, Worcester, MA, 01609, USA.
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2
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Deserno M. Biomembranes balance many types of leaflet asymmetries. Curr Opin Struct Biol 2024; 87:102832. [PMID: 38735128 DOI: 10.1016/j.sbi.2024.102832] [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: 12/14/2023] [Revised: 03/18/2024] [Accepted: 04/22/2024] [Indexed: 05/14/2024]
Abstract
Many biological membranes host different lipid species in their two leaflets. Since their spontaneous curvatures are typically not the same, this compositional asymmetry generally entails bending torques, which can be counteracted by differential stress-the difference between the two leaflet tensions. This stress, in turn, can affect elastic parameters or phase behavior of the membrane or each individual leaflet, or push easily flippable species, especially cholesterol, from the compressed leaflet into the tense leaflet. In short, breaking the symmetry of a single observable (to wit: composition), essentially breaks all other symmetries as well, with many potentially interesting consequences. This brief report examines the elastic aspects of this interplay, focusing on some elementary conditions of mechanical and thermodynamic equilibrium, but also shows how this poses novel questions that we are only beginning to appreciate.
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Affiliation(s)
- Markus Deserno
- Department of Physics, Carnegie Mellon University, 5000 Forbes Ave, Pittsburgh, PA 15213, USA.
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3
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Chaisson EH, Heberle FA, Doktorova M. Building Asymmetric Lipid Bilayers for Molecular Dynamics Simulations: What Methods Exist and How to Choose One? MEMBRANES 2023; 13:629. [PMID: 37504995 PMCID: PMC10384462 DOI: 10.3390/membranes13070629] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2023] [Revised: 06/20/2023] [Accepted: 06/25/2023] [Indexed: 07/29/2023]
Abstract
The compositional asymmetry of biological membranes has attracted significant attention over the last decade. Harboring more differences from symmetric membranes than previously appreciated, asymmetric bilayers have proven quite challenging to study with familiar concepts and techniques, leaving many unanswered questions about the reach of the asymmetry effects. One particular area of active research is the computational investigation of composition- and number-asymmetric lipid bilayers with molecular dynamics (MD) simulations. Offering a high level of detail into the organization and properties of the simulated systems, MD has emerged as an indispensable tool in the study of membrane asymmetry. However, the realization that results depend heavily on the protocol used for constructing the asymmetric bilayer models has sparked an ongoing debate about how to choose the most appropriate approach. Here we discuss the underlying source of the discrepant results and review the existing methods for creating asymmetric bilayers for MD simulations. Considering the available data, we argue that each method is well suited for specific applications and hence there is no single best approach. Instead, the choice of a construction protocol-and consequently, its perceived accuracy-must be based primarily on the scientific question that the simulations are designed to address.
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Affiliation(s)
- Emily H. Chaisson
- Department of Chemistry, University of Tennessee Knoxville, Knoxville, TN 37916, USA
| | - Frederick A. Heberle
- Department of Chemistry, University of Tennessee Knoxville, Knoxville, TN 37916, USA
| | - Milka Doktorova
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22903, USA
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4
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Aghaaminiha M, Farnoud AM, Sharma S. Interdependence of cholesterol distribution and conformational order in lipid bilayers. Biointerphases 2023; 18:2887740. [PMID: 37125848 DOI: 10.1116/6.0002489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Accepted: 04/11/2023] [Indexed: 05/02/2023] Open
Abstract
We show, via molecular simulations, that not only does cholesterol induce a lipid order, but the lipid order also enhances cholesterol localization within the lipid leaflets. Therefore, there is a strong interdependence between these two phenomena. In the ordered phase, cholesterol molecules are predominantly present in the bilayer leaflets and orient themselves parallel to the bilayer normal. In the disordered phase, cholesterol molecules are mainly present near the center of the bilayer at the midplane region and are oriented orthogonal to the bilayer normal. At the melting temperature of the lipid bilayers, cholesterol concentration in the leaflets and the bilayer midplane is equal. This result suggests that the localization of cholesterol in the lipid bilayers is mainly dictated by the degree of ordering of the lipid bilayer. We validate our findings on 18 different lipid bilayer systems, obtained from three different phospholipid bilayers with varying concentrations of cholesterol. To cover a large temperature range in simulations, we employ the Dry Martini force field. We demonstrate that the Dry and the Wet Martini (with polarizable water) force fields produce comparable results.
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Affiliation(s)
| | - Amir M Farnoud
- Department of Chemical and Biomolecular Engineering, Ohio University, Athens, Ohio 45701
| | - Sumit Sharma
- Department of Chemical and Biomolecular Engineering, Ohio University, Athens, Ohio 45701
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5
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Coleman PS, Parlo RA. Cancer’s Camouflage — Microvesicle Shedding from Cholesterol-Rich Tumor Plasma Membranes Might Blindfold First-Responder Immunosurveillance Strategies. Eur J Cell Biol 2022; 101:151219. [DOI: 10.1016/j.ejcb.2022.151219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 03/14/2022] [Accepted: 03/20/2022] [Indexed: 11/03/2022] Open
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6
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Aghaaminiha M, Farnoud AM, Sharma S. Quantitative relationship between cholesterol distribution and ordering of lipids in asymmetric lipid bilayers. SOFT MATTER 2021; 17:2742-2752. [PMID: 33533367 DOI: 10.1039/d0sm01709d] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The plasma membrane of eukaryotic cells is known to be compositionally asymmetric. Certain phospholipids, such as sphingomyelin and phosphatidylcholine species, are predominantly localized in the outer leaflet, while phosphatidylethanolamine and phosphatidylserine species primarily reside in the inner leaflet. While phospholipid asymmetry between the membrane leaflets is well established, there is no consensus about cholesterol distribution between the two leaflets. We have performed a systematic study, via molecular simulations, of how the spatial distribution of cholesterol molecules in different "asymmetric" lipid bilayers are affected by the lipids' backbone, head-type, unsaturation, and chain-length by considering an asymmetric bilayer mimicking the plasma membrane lipids of red blood cells, as well as seventeen other asymmetric bilayers comprising of different lipid types. Our results reveal that the distribution of cholesterol in the leaflets is solely a function of the extent of ordering of the lipids within the leaflets. The ratio of the amount of cholesterol matches the ratio of lipid order in the two leaflets, thus providing a quantitative relationship between the two. These results are understood by the observation that asymmetric bilayers with equimolar amount of lipids in the two leaflets develop tensile and compressive stresses due to differences in the extent of lipid order. These stresses are alleviated by the transfer of cholesterol from the leaflet in compressive stress to the one in tensile stress. These findings are important in understanding the biology of the cell membrane, especially with regard to the composition of the membrane leaflets.
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Affiliation(s)
- Mohammadreza Aghaaminiha
- Department of Chemical and Biomolecular Engineering, Russ College of Engineering and Technology, Ohio University, Athens, OH 45701, USA.
| | - Amir M Farnoud
- Department of Chemical and Biomolecular Engineering, Russ College of Engineering and Technology, Ohio University, Athens, OH 45701, USA.
| | - Sumit Sharma
- Department of Chemical and Biomolecular Engineering, Russ College of Engineering and Technology, Ohio University, Athens, OH 45701, USA.
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7
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Karlsen ML, Bruhn DS, Pezeshkian W, Khandelia H. Long chain sphingomyelin depletes cholesterol from the cytoplasmic leaflet in asymmetric lipid membranes. RSC Adv 2021; 11:22677-22682. [PMID: 35480443 PMCID: PMC9034350 DOI: 10.1039/d1ra01464a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 06/16/2021] [Indexed: 12/28/2022] Open
Abstract
The transbilayer distribution of cholesterol (CHL) in complex asymmetric lipid membranes remains controversial, with contrasting investigations suggesting that there is more CHL either in the exoplasmic, outer leaflet (OL) or the cytoplasmic, inner leaflet (IL) depending on cell type or model, membrane composition, and method of investigation. Here, we launch systematic coarse-grained molecular dynamics simulations to investigate the impact of the sphingomyelin (SM) acyl chain length upon CHL distribution in asymmetric lipid membrane mixtures which account for the variation of the most abundant headgroups and acyl chain unsaturation in the two membrane leaflets. We find that there is always more CHL in the OL, but longer chain SM depletes more CHL from the IL than short chain SM in simple membrane mixtures containing SM and 16 : 0, 18 : 1 phospholipids. The difference between longer and shorter chain SM is neutralised in a more complex asymmetric membrane, where there are more saturated tails in the outer leaflet. We propose that interdigitation of long-chain SM into the opposing IL pushes cytoplasmic CHL towards the OL, but higher chain saturation of the outer leaflet compensates for the effect of SM chain length. Long acyl chain sphingomyelin and saturated phospholipid tails in the outer membrane leaflet deplete cholesterol from the inner leaflet in mammalian membranes.![]()
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Affiliation(s)
- Maria Lyngby Karlsen
- PHYLIFE: Physical Life Science
- Department of Physics, Chemistry and Pharmacy
- University of Southern Denmark
- Odense 5230 M
- Denmark
| | - Dennis S. Bruhn
- PHYLIFE: Physical Life Science
- Department of Physics, Chemistry and Pharmacy
- University of Southern Denmark
- Odense 5230 M
- Denmark
| | - Weria Pezeshkian
- PHYLIFE: Physical Life Science
- Department of Physics, Chemistry and Pharmacy
- University of Southern Denmark
- Odense 5230 M
- Denmark
| | - Himanshu Khandelia
- PHYLIFE: Physical Life Science
- Department of Physics, Chemistry and Pharmacy
- University of Southern Denmark
- Odense 5230 M
- Denmark
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8
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Rafieiolhosseini N, Ejtehadi MR. Thermal conductivity of the cell membrane in the presence of cholesterol and amyloid precursor protein. Phys Rev E 2020; 102:042401. [PMID: 33212660 DOI: 10.1103/physreve.102.042401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Accepted: 09/16/2020] [Indexed: 12/11/2022]
Abstract
The cell membrane is responsible for the transportation of heat between inside and outside the cell. Whether the thermal properties of the cell membrane are affected by the cholesterol concentration or the membrane proteins has not been investigated so far. Although the experimental measurement of the membrane thermal conductivity was not available until very recently, computational methods have been widely used for this purpose. In this study, we carry out molecular dynamics simulations to investigate the relation between the concentration of cholesterol and the thermal conductivity of a model membrane. Our results suggest an increase in the membrane thermal conductivity upon increasing the concentration of cholesterol in the membrane. Moreover, we find that the asymmetric distribution of cholesterol in the two membrane leaflets decreases thermal conductivity. We also find a rectification effect when heat flows in opposite directions through a model membrane decorated with the amyloid precursor protein. The results of this study apply to the advancement of selective treatment methods, as well as the development of new materials such as biological rectifiers.
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Affiliation(s)
- Neda Rafieiolhosseini
- School of Nano Science, Institute for Research in Fundamental Sciences (IPM), P. O. Box 19395-5531, Tehran, Iran
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9
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Abstract
Cholesterol homeostasis and trafficking are critical to the maintenance of the asymmetric plasma membrane of eukaryotic cells. Disruption or dysfunction of cholesterol trafficking leads to numerous human diseases. ATP-binding cassette (ABC) transporters play several critical roles in this process, and mutations in these sterol transporters lead to disorders such as Tangier disease and sitosterolemia. Biochemical and structural information on ABC sterol transporters is beginning to emerge, with published structures of ABCA1 and ABCG5/G8; these two proteins function in the reverse cholesterol transport pathway and mediate the efflux of cholesterol and xenosterols to high-density lipoprotein and bile salt micelles, respectively. Although both of these transporters belong to the ABC family and mediate the efflux of a sterol substrate, they have many distinct differences. Here, we summarize the current understanding of sterol transport driven by ABC transporters, with an emphasis on these two extensively characterized transporters.
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Affiliation(s)
- Ashlee M Plummer
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, USA;
| | - Alan T Culbertson
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, USA;
| | - Maofu Liao
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, USA;
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10
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Direct and indirect cholesterol effects on membrane proteins with special focus on potassium channels. Biochim Biophys Acta Mol Cell Biol Lipids 2020; 1865:158706. [DOI: 10.1016/j.bbalip.2020.158706] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 03/19/2020] [Accepted: 03/30/2020] [Indexed: 12/16/2022]
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11
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Thangapandian S, Kapoor K, Tajkhorshid E. Probing cholesterol binding and translocation in P-glycoprotein. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2020; 1862:183090. [PMID: 31676371 PMCID: PMC6934093 DOI: 10.1016/j.bbamem.2019.183090] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Revised: 09/15/2019] [Accepted: 09/17/2019] [Indexed: 01/01/2023]
Abstract
P-glycoprotein (Pgp) is a biomedically important member of the ABC transporter superfamily that mediates multidrug resistance in various cancer types. Substrate binding and transport in Pgp are modulated by the presence of cholesterol in the membrane. Structural information on cholesterol binding sites and mechanistic details of its redistribution are, however, largely unknown. In this study, a set of 40 independent molecular dynamics (MD) simulations of Pgp embedded in cholesterol-rich lipid bilayers are reported, totaling 8 μs, enabling extensive sampling of cholesterol-protein interactions in Pgp. Clustering analyses of the ensemble of cholesterol molecules (∼5740) sampled around Pgp in these simulations reveal specific and asymmetric cholesterol-binding regions formed by the transmembrane (TM) helices TM1-6 and TM8. Notably, not all the putative cholesterol binding sites identified by MD can be predicted by the primary sequence based cholesterol-recognition amino acid consensus (CRAC) or inverted CRAC (CARC) motifs, an observation that we attribute to inadequacy of these motifs to account for binding sites formed by remote amino acids in the sequence that can still be spatially adjacent to each other. Binding of cholesterol to Pgp occurs more frequently through its rough β-face formed by the two protruding methyl groups, whereas the opposite smooth α-face prefers packing alongside the membrane lipids. One full and two partial cholesterol flipping events between the two leaflets of the bilayer mediated by the surface of Pgp are also captured in these simulations. All flipping events are observed in a region formed by helices TM1, TM2, and TM11, featuring two full and two partial CRAC/CARC motifs, with Tyr49 and Tyr126 identified as key residues interacting with cholesterol during this event. Our study is the first to report direct observation of unconventional cholesterol translocation on the surface of Pgp, providing a secondary transport model for the known flippase activity of ABC exporters of cholesterol. This article is part of a Special Issue entitled: Molecular biophysics of membranes and membrane proteins.
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Affiliation(s)
- Sundar Thangapandian
- NIH Center for Molecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, Department of Biochemistry, Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Karan Kapoor
- NIH Center for Molecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, Department of Biochemistry, Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Emad Tajkhorshid
- NIH Center for Molecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, Department of Biochemistry, Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
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12
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Yesylevskyy S, Rivel T, Ramseyer C. Curvature increases permeability of the plasma membrane for ions, water and the anti-cancer drugs cisplatin and gemcitabine. Sci Rep 2019; 9:17214. [PMID: 31748538 PMCID: PMC6868207 DOI: 10.1038/s41598-019-53952-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2019] [Accepted: 09/26/2019] [Indexed: 01/15/2023] Open
Abstract
In this work the permeability of a model asymmetric plasma membrane, for ions, water and the anti-cancer drugs cisplatin and gemcitabine is studied by means of all-atom molecular dynamics simulations. It is shown for the first time that permeability of the highly curved membrane increases from one to three orders of magnitude upon membrane bending depending on the compound and the sign of curvature. Our results suggest that the membrane curvature could be an important factor of drug translocation through the membrane.
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Affiliation(s)
- Semen Yesylevskyy
- Laboratoire Chrono Environnement UMR CNRS 6249, Université de Bourgogne Franche-Comté, 16 route de Gray, 25030, Besançon, Cedex, France.
- Department of Physics of Biological Systems, Institute of Physics of the National Academy of Sciences of Ukraine, Prospect Nauky 46, 03028, Kyiv, Ukraine.
| | - Timothée Rivel
- Laboratoire Chrono Environnement UMR CNRS 6249, Université de Bourgogne Franche-Comté, 16 route de Gray, 25030, Besançon, Cedex, France
| | - Christophe Ramseyer
- Laboratoire Chrono Environnement UMR CNRS 6249, Université de Bourgogne Franche-Comté, 16 route de Gray, 25030, Besançon, Cedex, France
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13
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Collard L, Sinjab F, Notingher I. Raman Spectroscopy Study of Curvature-Mediated Lipid Packing and Sorting in Single Lipid Vesicles. Biophys J 2019; 117:1589-1598. [PMID: 31587827 PMCID: PMC6839040 DOI: 10.1016/j.bpj.2019.09.020] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 09/12/2019] [Accepted: 09/13/2019] [Indexed: 01/07/2023] Open
Abstract
Cellular plasma membrane deformability and stability is important in a range of biological processes. Changes in local curvature of the membrane affect the lateral movement of lipids, affecting the biophysical properties of the membrane. An integrated holographic optical tweezers and Raman microscope was used to investigate the effect of curvature gradients induced by optically stretching individual giant unilamellar vesicles (GUVs) on lipid packing and lateral segregation of cholesterol in the bilayer. The spatially resolved Raman analysis enabled detection of induced phase separation and changes in lipid ordering in individual GUVs. Using deuterated cholesterol, the changes in lipid ordering and phase separation were linked to lateral sorting of cholesterol in the stretched GUVs. Stretching the GUVs in the range of elongation factors 1-1.3 led to an overall decrease in cholesterol concentration at the edges compared to the center of stretched GUVs. The Raman spectroscopy results were consistent with a model of the bilayer accounting for cholesterol sorting in both bilayer leaflets, with a compositional asymmetry of 0.63 ± 0.04 in favor of the outer leaflet. The results demonstrate the potential of the integrated holographic optical tweezers-Raman technique to induce deformations to individual lipid vesicles and to simultaneously provide quantitative and spatially resolved molecular information. Future studies can extend to include more realistic models of cell membranes and potentially live cells.
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Affiliation(s)
- Liam Collard
- School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, United Kingdom
| | - Faris Sinjab
- School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, United Kingdom
| | - Ioan Notingher
- School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, United Kingdom.
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14
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Enkavi G, Javanainen M, Kulig W, Róg T, Vattulainen I. Multiscale Simulations of Biological Membranes: The Challenge To Understand Biological Phenomena in a Living Substance. Chem Rev 2019; 119:5607-5774. [PMID: 30859819 PMCID: PMC6727218 DOI: 10.1021/acs.chemrev.8b00538] [Citation(s) in RCA: 175] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Indexed: 12/23/2022]
Abstract
Biological membranes are tricky to investigate. They are complex in terms of molecular composition and structure, functional over a wide range of time scales, and characterized by nonequilibrium conditions. Because of all of these features, simulations are a great technique to study biomembrane behavior. A significant part of the functional processes in biological membranes takes place at the molecular level; thus computer simulations are the method of choice to explore how their properties emerge from specific molecular features and how the interplay among the numerous molecules gives rise to function over spatial and time scales larger than the molecular ones. In this review, we focus on this broad theme. We discuss the current state-of-the-art of biomembrane simulations that, until now, have largely focused on a rather narrow picture of the complexity of the membranes. Given this, we also discuss the challenges that we should unravel in the foreseeable future. Numerous features such as the actin-cytoskeleton network, the glycocalyx network, and nonequilibrium transport under ATP-driven conditions have so far received very little attention; however, the potential of simulations to solve them would be exceptionally high. A major milestone for this research would be that one day we could say that computer simulations genuinely research biological membranes, not just lipid bilayers.
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Affiliation(s)
- Giray Enkavi
- Department
of Physics, University of
Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
| | - Matti Javanainen
- Department
of Physics, University of
Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
- Institute
of Organic Chemistry and Biochemistry of the Czech Academy
of Sciences, Flemingovo naḿesti 542/2, 16610 Prague, Czech Republic
- Computational
Physics Laboratory, Tampere University, P.O. Box 692, FI-33014 Tampere, Finland
| | - Waldemar Kulig
- Department
of Physics, University of
Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
| | - Tomasz Róg
- Department
of Physics, University of
Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
- Computational
Physics Laboratory, Tampere University, P.O. Box 692, FI-33014 Tampere, Finland
| | - Ilpo Vattulainen
- Department
of Physics, University of
Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
- Computational
Physics Laboratory, Tampere University, P.O. Box 692, FI-33014 Tampere, Finland
- MEMPHYS-Center
for Biomembrane Physics
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15
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Rivel T, Ramseyer C, Yesylevskyy S. The asymmetry of plasma membranes and their cholesterol content influence the uptake of cisplatin. Sci Rep 2019; 9:5627. [PMID: 30948733 PMCID: PMC6449338 DOI: 10.1038/s41598-019-41903-w] [Citation(s) in RCA: 81] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 03/18/2019] [Indexed: 12/20/2022] Open
Abstract
The composition of the plasma membrane of malignant cells is thought to influence the cellular uptake of cisplatin and to take part in developing resistance to this widespread anti-cancer drug. In this work we study the permeation of cisplatin through the model membranes of normal and cancer cells using molecular dynamics simulations. A special attention is paid to lipid asymmetry and cholesterol content of the membranes. The loss of lipid asymmetry, which is common for cancer cells, leads to a decrease in their permeability to cisplatin by one order of magnitude in comparison to the membranes of normal cells. The change in the cholesterol molar ratio from 0% to 33% also decreases the permeability of the membrane by approximately one order of magnitude. The permeability of pure DOPC membrane is 5-6 orders of magnitude higher than one of the membranes with realistic lipid composition, which makes it as an inadequate model for the studies of drug permeability.
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Affiliation(s)
- Timothée Rivel
- Laboratoire Chrono Environnement UMR CNRS 6249, Université de Bourgogne Franche-Comté, 16 route de Gray, 25030, Besançon, Cedex, France.
| | - Christophe Ramseyer
- Laboratoire Chrono Environnement UMR CNRS 6249, Université de Bourgogne Franche-Comté, 16 route de Gray, 25030, Besançon, Cedex, France
| | - Semen Yesylevskyy
- Laboratoire Chrono Environnement UMR CNRS 6249, Université de Bourgogne Franche-Comté, 16 route de Gray, 25030, Besançon, Cedex, France.,Department of Physics of Biological Systems, Institute of Physics of the National Academy of Sciences of Ukraine, Prospect Nauky 46, 03028, Kyiv, Ukraine
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16
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Steck TL, Lange Y. Transverse distribution of plasma membrane bilayer cholesterol: Picking sides. Traffic 2018; 19:750-760. [PMID: 29896788 DOI: 10.1111/tra.12586] [Citation(s) in RCA: 88] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 06/04/2018] [Accepted: 06/05/2018] [Indexed: 12/23/2022]
Abstract
The transverse asymmetry (sidedness) of phospholipids in plasma membrane bilayers is well characterized, distinctive, actively maintained and functionally important. In contrast, numerous studies using a variety of techniques have concluded that plasma membrane bilayer cholesterol is either mostly in the outer leaflet or the inner leaflet or is fairly evenly distributed. Sterols might simply partition according to their differing affinities for the asymmetrically disposed phospholipids, but some studies have proposed that it is actively transported to the outer leaflet. Other work suggests that the sterol is enriched in the inner leaflet, driven by either positive interactions with the phosphatidylethanolamine on that side or by its exclusion from the outer leaflet by the long chain sphingomyelin molecules therein. This uncertainty raises three questions: is plasma membrane cholesterol sidedness fixed in a given cell or cell type; is it generally the same among mammalian species; and does it serve specific physiological functions? This review grapples with these issues.
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Affiliation(s)
- Theodore L Steck
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois
| | - Yvonne Lange
- Department of Pathology, Rush University Medical Center, Chicago, Illinois
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17
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Urakami N, Jimbo T, Sakuma Y, Imai M. Molecular mechanism of vesicle division induced by coupling between lipid geometry and membrane curvatures. SOFT MATTER 2018. [PMID: 29517793 DOI: 10.1039/c7sm02188g] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
We investigated the effects of lipid geometry on vesicle division using coarse grained molecular dynamics simulations. When the vesicle is composed of zero and negative spontaneous curvature lipids (ZSLs and NSLs), the difference in their molecular spontaneous curvatures destabilizes the neck of the limiting shape vesicle. In the vesicle division pathway, the neck developed into the stalk intermediates. The stalk was broken when the NSLs were expelled from the stalk. Free energy analysis shows that the coupling between the lipid geometry and the Gaussian rigidity is responsible for the observed vesicle division.
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Affiliation(s)
- Naohito Urakami
- Department of Physics and Informatics, Yamaguchi University, 1677-1 Yoshida, Yamaguchi, 753-8512, Japan.
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18
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Yesylevskyy SO, Rivel T, Ramseyer C. The influence of curvature on the properties of the plasma membrane. Insights from atomistic molecular dynamics simulations. Sci Rep 2017; 7:16078. [PMID: 29167583 PMCID: PMC5700167 DOI: 10.1038/s41598-017-16450-x] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Accepted: 11/13/2017] [Indexed: 11/24/2022] Open
Abstract
In this work we conduct a systematic analysis of the influence of curvature on various properties of a realistic model of mammalian plasma membrane with asymmetric lipid content of monolayers and a realistic concentration of cholesterol. In order to do this we developed new technique for simulating membranes with the global membrane curvature restricted to any desirable value while keeping free lateral diffusion of the lipids and without introducing artifacts or perturbing the membrane structure. We show that the thickness of the hydrophobic core of the concave monolayer decreases by approximately 1.3 Å in comparison to that of the flat membrane, while the thickness of the convex monolayer does not change. The order parameter of the lipid tails decreases significantly in the certain layers of the curved membrane. The area per lipid increases in the convex monolayer and decreases in the concave monolayer. The cholesterol inclination angle decreases when the curvature of a particular monolayer changes from concave to convex. The amount of cholesterol in the minor fraction located between the membrane leaflets is zero in the membrane with positive curvature and increases to 1.7% in the flat membrane and to 2.5% in the membrane with negative curvature.
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Affiliation(s)
- Semen O Yesylevskyy
- Department of Physics of Biological Systems, Institute of Physics of the National Academy of Sciences of Ukraine, Prospect Nauky 46, Kyiv, 03680, Ukraine.
| | - Timothée Rivel
- Laboratoire Chrono Environnement UMR CNRS 6249, Université de Bourgogne Franche-Comté, 16 route de Gray, 25030, Besançon, Cedex, France
| | - Christophe Ramseyer
- Laboratoire Chrono Environnement UMR CNRS 6249, Université de Bourgogne Franche-Comté, 16 route de Gray, 25030, Besançon, Cedex, France
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19
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Nawae W, Hannongbua S, Ruengjitchatchawalya M. Molecular dynamics exploration of poration and leaking caused by Kalata B1 in HIV-infected cell membrane compared to host and HIV membranes. Sci Rep 2017; 7:3638. [PMID: 28620219 PMCID: PMC5472625 DOI: 10.1038/s41598-017-03745-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 05/05/2017] [Indexed: 12/21/2022] Open
Abstract
The membrane disruption activities of kalata B1 (kB1) were investigated using molecular dynamics simulations with membrane models. The models were constructed to mimic the lipid microdomain formation in membranes of HIV particle, HIV-infected cell, and host cell. The differences in the lipid ratios of these membranes caused the formation of liquid ordered (lo) domains of different sizes, which affected the binding and activity of kB1. Stronger kB1 disruptive activity was observed for the membrane with small sized lo domain. Our results show that kB1 causes membrane leaking without bilayer penetration. The membrane poration mechanism involved in the disorganization of the lo domain and in cholesterol inter-leaflet translocation is described. This study enhances our understanding of the membrane activity of kB1, which may be useful for designing novel and potentially therapeutic peptides based on the kB1 framework.
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Affiliation(s)
- Wanapinun Nawae
- Pilot Plant Development and Training Institution, King Mongkut's University of Technology Thonburi (Bang Khun Thian Campus), 49 Soi Thian Thale 25, Bang Khun Thian Chai Thale Rd., Tha Kham, Bang Khun Thian, Bangkok, 10150, Thailand
| | - Supa Hannongbua
- Department of Chemistry, Kasetsart University, 50 Phaholyothin Rd., Ladyao, Chatuchak, Bangkok, Thailand, 10900
| | - Marasri Ruengjitchatchawalya
- Biotechnology Program, School of Bioresources and Technology, King Mongkut's University of Technology Thonburi (Bang KhunThian Campus), 49 Soi Thian Thale 25, Bang Khun Thian Chai Thale Rd., Tha Kham, Bang Khun Thian, Bangkok, 10150, Thailand.
- Bioinformatics and Systems Biology Program, King Mongkut's University of Technology Thonburi (Bang Khun Thian Campus), 49 Soi Thian Thale 25, Bang Khun Thian Chai Thale Rd., Tha Kham, Bang Khun Thian, Bangkok, 10150, Thailand.
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20
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Marquardt D, Kučerka N, Wassall SR, Harroun TA, Katsaras J. Cholesterol's location in lipid bilayers. Chem Phys Lipids 2016; 199:17-25. [DOI: 10.1016/j.chemphyslip.2016.04.001] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2016] [Revised: 04/01/2016] [Accepted: 04/02/2016] [Indexed: 02/07/2023]
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21
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Cherniavskyi YK, Ramseyer C, Yesylevskyy SO. Interaction of C60 fullerenes with asymmetric and curved lipid membranes: a molecular dynamics study. Phys Chem Chem Phys 2015; 18:278-84. [PMID: 26608905 DOI: 10.1039/c5cp05838d] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Interaction of fullerenes with asymmetric and curved DOPC/DOPS bicelles is studied by means of coarse-grained molecular dynamics simulations. The effects caused by asymmetric lipid composition of the membrane leaflets and the curvature of the membrane are analyzed. It is shown that the aggregates of fullerenes prefer to penetrate into the membrane in the regions of the moderately positive mean curvature. Upon penetration into the hydrophobic core of the membrane fullerenes avoid the regions of the extreme positive or the negative curvature. Fullerenes increase the ordering of lipid tails, which are in direct contact with them, but do not influence other lipids significantly. Our data suggest that the effects of the membrane curvature should be taken into account in the studies concerning permeability of the membranes to fullerenes and fullerene-based drug delivery systems.
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Affiliation(s)
- Yevhen K Cherniavskyi
- Department of Physics of Biological Systems, Institute of Physics of the National Academy of Sciences of Ukraine, Prospect Nauky 46, Kiev-28, 03680, Ukraine.
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22
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Yesylevskyy SO. Pteros 2.0: Evolution of the fast parallel molecular analysis library for C++ and python. J Comput Chem 2015; 36:1480-8. [DOI: 10.1002/jcc.23943] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Revised: 04/26/2015] [Accepted: 04/27/2015] [Indexed: 11/12/2022]
Affiliation(s)
- Semen O. Yesylevskyy
- Department of Physics of Biological Systems; Institute of Physics, National Academy of Sciences of Ukraine; Prospect Nauki, 46, Kyiv-03039 Ukraine
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23
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Marquardt D, Geier B, Pabst G. Asymmetric lipid membranes: towards more realistic model systems. MEMBRANES 2015; 5:180-96. [PMID: 25955841 PMCID: PMC4496639 DOI: 10.3390/membranes5020180] [Citation(s) in RCA: 150] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Accepted: 04/28/2015] [Indexed: 01/23/2023]
Abstract
Despite the ubiquity of transbilayer asymmetry in natural cell membranes, the vast majority of existing research has utilized chemically well-defined symmetric liposomes, where the inner and outer bilayer leaflets have the same composition. Here, we review various aspects of asymmetry in nature and in model systems in anticipation for the next phase of model membrane studies.
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Affiliation(s)
- Drew Marquardt
- Institute of Molecular Biosciences, Biophysics Division, University of Graz, NAWI Graz, Humboldtstr 50/III, Graz, 8010, Austria.
- BioTechMed-Graz, Graz, 8010, Austria.
| | - Barbara Geier
- Institute of Molecular Biosciences, Biophysics Division, University of Graz, NAWI Graz, Humboldtstr 50/III, Graz, 8010, Austria.
- BioTechMed-Graz, Graz, 8010, Austria.
| | - Georg Pabst
- Institute of Molecular Biosciences, Biophysics Division, University of Graz, NAWI Graz, Humboldtstr 50/III, Graz, 8010, Austria.
- BioTechMed-Graz, Graz, 8010, Austria.
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24
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Yesylevskyy SO, Demchenko AP. Cholesterol behavior in asymmetric lipid bilayers: insights from molecular dynamics simulations. Methods Mol Biol 2015; 1232:291-306. [PMID: 25331142 DOI: 10.1007/978-1-4939-1752-5_20] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Asymmetric lipid composition of the cell membranes plays an important role in the multitude of important biological functions. Much less is known, however, about the distribution and dynamics of cholesterol in asymmetric biological membranes. In this work we show how this issue could be addressed computationally by molecular dynamics simulations. The influence of the lipid head group charge, acyl chain saturation, spontaneous membrane curvature and the surface tension of the membrane on cholesterol distribution in asymmetric lipid bilayers is investigated. Four asymmetric bilayers containing DOPC, DOPS, DSPC, or DSPS lipids, were simulated on the time scale extended to tens of microseconds. We show that cholesterol strongly prefers anionic lipids to neutral and saturated lipid tails to unsaturated with distribution ratio ~0.4-0.6. Multiple flip-flop transitions of cholesterol were observed directly and their mean times range from 350 to 2,000 ns. It was shown that the distribution of cholesterol in the asymmetric bilayer depends not only on the type of lipids but also on the local membrane curvature and the surface tension. The geometric shape of spontaneously curved asymmetric bilayer changes dramatically in the presence of cholesterol. The membrane curvature becomes less homogeneous with large patches of flattened regions interleaved by rather sharp bends.
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Affiliation(s)
- Semen O Yesylevskyy
- Institute of Physics, National Academy of Sciences of Ukraine, Prospect Nauky, 46, Kiev, 03039, Ukraine,
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25
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Róg T, Vattulainen I. Cholesterol, sphingolipids, and glycolipids: what do we know about their role in raft-like membranes? Chem Phys Lipids 2014; 184:82-104. [PMID: 25444976 DOI: 10.1016/j.chemphyslip.2014.10.004] [Citation(s) in RCA: 140] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2014] [Revised: 10/24/2014] [Accepted: 10/25/2014] [Indexed: 12/14/2022]
Abstract
Lipids rafts are considered to be functional nanoscale membrane domains enriched in cholesterol and sphingolipids, characteristic in particular of the external leaflet of cell membranes. Lipids, together with membrane-associated proteins, are therefore considered to form nanoscale units with potential specific functions. Although the understanding of the structure of rafts in living cells is quite limited, the possible functions of rafts are widely discussed in the literature, highlighting their importance in cellular functions. In this review, we discuss the understanding of rafts that has emerged based on recent atomistic and coarse-grained molecular dynamics simulation studies on the key lipid raft components, which include cholesterol, sphingolipids, glycolipids, and the proteins interacting with these classes of lipids. The simulation results are compared to experiments when possible.
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Affiliation(s)
- Tomasz Róg
- Department of Physics, Tampere University of Technology, Tampere, Finland
| | - Ilpo Vattulainen
- Department of Physics, Tampere University of Technology, Tampere, Finland; MEMPHYS-Center for Biomembrane Physics, University of Southern Denmark, Odense, Denmark.
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26
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Koldsø H, Shorthouse D, Hélie J, Sansom MSP. Lipid clustering correlates with membrane curvature as revealed by molecular simulations of complex lipid bilayers. PLoS Comput Biol 2014; 10:e1003911. [PMID: 25340788 PMCID: PMC4207469 DOI: 10.1371/journal.pcbi.1003911] [Citation(s) in RCA: 169] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Accepted: 09/16/2014] [Indexed: 12/21/2022] Open
Abstract
Cell membranes are complex multicomponent systems, which are highly heterogeneous in the lipid distribution and composition. To date, most molecular simulations have focussed on relatively simple lipid compositions, helping to inform our understanding of in vitro experimental studies. Here we describe on simulations of complex asymmetric plasma membrane model, which contains seven different lipids species including the glycolipid GM3 in the outer leaflet and the anionic lipid, phosphatidylinositol 4,5-bisphophate (PIP2), in the inner leaflet. Plasma membrane models consisting of 1500 lipids and resembling the in vivo composition were constructed and simulations were run for 5 µs. In these simulations the most striking feature was the formation of nano-clusters of GM3 within the outer leaflet. In simulations of protein interactions within a plasma membrane model, GM3, PIP2, and cholesterol all formed favorable interactions with the model α-helical protein. A larger scale simulation of a model plasma membrane containing 6000 lipid molecules revealed correlations between curvature of the bilayer surface and clustering of lipid molecules. In particular, the concave (when viewed from the extracellular side) regions of the bilayer surface were locally enriched in GM3. In summary, these simulations explore the nanoscale dynamics of model bilayers which mimic the in vivo lipid composition of mammalian plasma membranes, revealing emergent nanoscale membrane organization which may be coupled both to fluctuations in local membrane geometry and to interactions with proteins. Cell membranes play important roles in vivo both in shielding the cell interior from the surrounding environment and in cell function through lipid components of the membrane having roles in controlling protein function, cell signaling etc. We employ molecular dynamics simulations to explore the behavior of biologically realistic membrane models. Our simulations reveal nano-domain clustering of the glycolipid GM3 and to a lesser extent of the anionic lipid phosphatidylinositol 4,5-bisphophate (PIP2). When including transmembrane proteins we are able to observe preferential interactions of known regulatory lipids (e.g. GM3, PIP2 and cholesterol) with the proteins. Membrane curvature is shown to be coupled to the local lipid composition, suggestive of a link between lipid nano-domains and membrane geometry.
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Affiliation(s)
- Heidi Koldsø
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - David Shorthouse
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Jean Hélie
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Mark S. P. Sansom
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
- * E-mail:
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27
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Yesylevskyy SO, Ramseyer C. Determination of mean and Gaussian curvatures of highly curved asymmetric lipid bilayers: the case study of the influence of cholesterol on the membrane shape. Phys Chem Chem Phys 2014; 16:17052-61. [DOI: 10.1039/c4cp01544d] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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28
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Yesylevskyy SO, Kraszewski S, Ramseyer C. Determination of the shape and curvature of nonplanar lipid bilayers that are bent in a single plane in molecular dynamics simulations. J Mol Model 2014; 20:2176. [DOI: 10.1007/s00894-014-2176-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Accepted: 02/08/2014] [Indexed: 11/29/2022]
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29
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Effect of cholesterol on behavior of 5-fluorouracil (5-FU) in a DMPC lipid bilayer, a molecular dynamics study. Biophys Chem 2014; 187-188:43-50. [DOI: 10.1016/j.bpc.2014.01.004] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Revised: 01/18/2014] [Accepted: 01/25/2014] [Indexed: 11/19/2022]
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30
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Li ZL, Wang JJ, Ding HM, Ma YQ. Influence of different membrane environments on the behavior of cholesterol. RSC Adv 2014. [DOI: 10.1039/c4ra08201j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Our results show the distribution of cholesterol between stress-free and stressed membranes or between the inner leaflet and the outer leaflet of curved membrane.
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Affiliation(s)
- Zhen-lu Li
- National Laboratory of Solid State Microstructures and Department of Physics
- Nanjing University
- Nanjing 210093, China
| | - Jing-jing Wang
- National Laboratory of Solid State Microstructures and Department of Physics
- Nanjing University
- Nanjing 210093, China
| | - Hong-ming Ding
- National Laboratory of Solid State Microstructures and Department of Physics
- Nanjing University
- Nanjing 210093, China
| | - Yu-qiang Ma
- National Laboratory of Solid State Microstructures and Department of Physics
- Nanjing University
- Nanjing 210093, China
- Center for Soft Condensed Matter Physics and Interdisciplinary Research
- Soochow University
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31
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Cholesterol induces uneven curvature of asymmetric lipid bilayers. ScientificWorldJournal 2013; 2013:965230. [PMID: 23766730 PMCID: PMC3671548 DOI: 10.1155/2013/965230] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Accepted: 04/28/2013] [Indexed: 01/07/2023] Open
Abstract
A remarkable flexibility is observed in biological membranes, which allows them to form the structures of different curvatures. We addressed the question of intrinsic ability of phospholipid membranes to form highly curved structures and the role of cholesterol in this process. The distribution of cholesterol in the highly curved asymmetric DOPC/DOPS lipid bilayer was investigated by the coarse-grained molecular dynamics simulations in the membrane patches with large aspect ratio. It is shown that cholesterol induces uneven membrane curvature promoting the formation of extended flattened regions of the membrane interleaved by sharp bends. It is shown that the affinity of cholesterol to anionic DOPS or neutral DOPC lipids is curvature dependent. The cholesterol prefers DOPS to DOPC in either planar or highly curved parts of the membrane. In contrast, in the narrow interval of moderate membrane curvatures this preference is inverted. Our data suggest that there is a complex self-consistent interplay between the membrane curvature and cholesterol distribution in the asymmetric lipid bilayers. The suggested new function of cholesterol may have a biological relevance.
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32
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