1
|
Suresh P, London E. MαCD-based plasma membrane outer leaflet lipid exchange in mammalian cells to study insulin receptor activity. Methods Enzymol 2024; 700:485-507. [PMID: 38971611 DOI: 10.1016/bs.mie.2024.03.027] [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] [Indexed: 07/08/2024]
Abstract
Signaling receptors on the plasma membrane, such as insulin receptor, can have their activity modulated to some extent by their surrounding lipids. Studying the contribution of membrane lipid properties such as presence of ordered lipid domains or bilayer thickness on the activity of receptors has been a challenging objective in living cells. Using methyl-alpha cyclodextrin-mediated lipid exchange, we are able to alter the lipids of the outer leaflet plasma membrane of mammalian cells to investigate the effect of the properties of the exchanged lipid upon receptor function in live cells. In this article, we describe the technique of lipid exchange in detail and how it can be applied to better understand lipid-mediated regulation of insulin receptor activity in cells.
Collapse
Affiliation(s)
- Pavana Suresh
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, United States.
| | - Erwin London
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY, United States
| |
Collapse
|
2
|
Heberle FA, Waxham MN. Phase separation in model lipid membranes investigated with cryogenic electron microscopy. Methods Enzymol 2024; 700:189-216. [PMID: 38971600 DOI: 10.1016/bs.mie.2024.03.003] [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] [Indexed: 07/08/2024]
Abstract
We describe a method for investigating lateral membrane heterogeneity using cryogenic electron microscopy (cryo-EM) images of liposomes. The method takes advantage of differences in the thickness and molecular density of ordered and disordered phases that are resolvable in phase contrast cryo-EM. Compared to biophysical techniques like FRET or neutron scattering that yield ensemble-averaged information, cryo-EM provides direct visualization of individual vesicles and can therefore reveal variability that would otherwise be obscured by averaging. Moreover, because the contrast mechanism involves inherent properties of the lipid phases themselves, no extrinsic probes are required. We explain and discuss various complementary analyses of spatially resolved thickness and intensity measurements that enable an assessment of the membrane's phase state. The method opens a window to nanodomain structure in synthetic and biological membranes that should lead to an improved understanding of lipid raft phenomena.
Collapse
Affiliation(s)
- Frederick A Heberle
- Department of Chemistry, University of Tennessee, Knoxville, TN, United States.
| | - M Neal Waxham
- Department of Neurobiology and Anatomy, University of Texas Health Science Center, Houston, TX, United States.
| |
Collapse
|
3
|
Park J, Ahn Y, Lee WJ, Jin S, Jeong S, Kim J, Lee YS, Lee JC, Seo D. Analysis of Phase Heterogeneity in Lipid Membranes Using Single-Molecule Tracking in Live Cells. Anal Chem 2023; 95:15924-15932. [PMID: 37774148 DOI: 10.1021/acs.analchem.3c02655] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/01/2023]
Abstract
In live cells, the plasma membrane is composed of lipid domains separated by hundreds of nanometers in dynamic equilibrium. Lipid phase separation regulates the trafficking and spatiotemporal organization of membrane molecules that promote signal transduction. However, visualizing domains with adequate spatiotemporal accuracy remains challenging because of their subdiffraction limit size and highly dynamic properties. Here, we present a single lipid-molecular motion analysis pipeline (lipid-MAP) for analyzing the phase heterogeneity of lipid membranes by detecting the instantaneous velocity change of a single lipid molecule using the excellent optical properties of nanoparticles, high spatial localization accuracy of single-molecule localization microscopy, and separation capability of the diffusion state of the hidden Markov model algorithm. Using lipid-MAP, individual lipid molecules were found to be in dynamic equilibrium between two statistically distinguishable phases, leading to the formation of small (∼170 nm), viscous (2.5× more viscous than surrounding areas), and transient domains in live cells. Moreover, our findings provide an understanding of how membrane compositional changes, i.e., cholesterol and phospholipids, affect domain formation. This imaging method can contribute to an improved understanding of spatiotemporal-controlled membrane dynamics at the molecular level.
Collapse
Affiliation(s)
- Jiseong Park
- Department of Physics and Chemistry, DGIST, Daegu 42988, Republic of Korea
| | - Yongdeok Ahn
- Department of Physics and Chemistry, DGIST, Daegu 42988, Republic of Korea
| | - Wonhee John Lee
- Department of Physics and Chemistry, DGIST, Daegu 42988, Republic of Korea
| | - Siwoo Jin
- Department of Physics and Chemistry, DGIST, Daegu 42988, Republic of Korea
| | - Sejoo Jeong
- Department of New Biology, DGIST, Daegu 42988, Republic of Korea
| | - Jaeyong Kim
- Department of New Biology, DGIST, Daegu 42988, Republic of Korea
| | - Young-Sam Lee
- Department of New Biology, DGIST, Daegu 42988, Republic of Korea
| | - Jong-Chan Lee
- Department of New Biology, DGIST, Daegu 42988, Republic of Korea
| | - Daeha Seo
- Department of Physics and Chemistry, DGIST, Daegu 42988, Republic of Korea
| |
Collapse
|
4
|
Krzyzanowski N, Porcar L, Perez-Salas U. A Small-Angle Neutron Scattering, Calorimetry and Densitometry Study to Detect Phase Boundaries and Nanoscale Domain Structure in a Binary Lipid Mixture. MEMBRANES 2023; 13:323. [PMID: 36984710 PMCID: PMC10051979 DOI: 10.3390/membranes13030323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 03/06/2023] [Accepted: 03/07/2023] [Indexed: 06/18/2023]
Abstract
Techniques that can probe nanometer length scales, such as small-angle neutron scattering (SANS), have become increasingly popular to detect phase separation in membranes. But to extract the phase composition and domain structure from the SANS traces, complementary information is needed. Here, we present a SANS, calorimetry and densitometry study of a mixture of two saturated lipids that exhibits solidus-liquidus phase coexistence: 1,2-dipalmitoyl-d62-sn-glycero-3-phosphocholine (dDPPC, tail-deuterated DPPC) and 1,2-dilauroyl-sn-glycero-3-phosphocholine (DLPC). With calorimetry, we investigated the phase diagram for this system and found that the boundary traces for both multilamellar vesicles (MLVs) as well as 50 nm unilamellar vesicles overlap. Because the solidus boundary was mostly inaccessible by calorimetry, we investigated it by both SANS and molecular volume measurements for a 1:1 dDPPC:DLPC lipid mixture. From the temperature behavior of the molecular volume for the 1:1 dDPPC:DLPC mixture, as well as the individual molecular volume of each lipid species, we inferred that the liquidus phase consists of only fluid-state lipids while the solidus phase consists of lipids that are in gel-like states. Using this solidus-liquidus phase model, the SANS data were analyzed with an unrestricted shape model analysis software: MONSA. The resulting fits show irregular domains with dendrite-like features as those previously observed on giant unilamellar vesicles (GUVs). The surface pair correlation function describes a characteristic domain size for the minority phase that decreases with temperature, a behavior found to be consistent with a concomitant decrease in membrane mismatch between the liquidus and solidus phases.
Collapse
Affiliation(s)
- Natalie Krzyzanowski
- Department of Physics, University of Illinois at Chicago, Chicago, IL 60608, USA
| | - Lionel Porcar
- Large Scale Structures Group, Institut Laue-Langevin, CEDEX 9, 38042 Grenoble, France
| | - Ursula Perez-Salas
- Department of Physics, University of Illinois at Chicago, Chicago, IL 60608, USA
| |
Collapse
|
5
|
Antifungal effect of the liposome encapsulation of the Trans- Caryophylene and its association with fluconazole. Chem Biol Interact 2023; 373:110377. [PMID: 36754224 DOI: 10.1016/j.cbi.2023.110377] [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: 01/04/2023] [Revised: 01/25/2023] [Accepted: 01/31/2023] [Indexed: 02/08/2023]
Abstract
Trans-Caryophyllene (TC), a sesquiterpene, with proven biological activities, which in this work was tested alone, encapsulated in liposomes and associated with Fluconazole in vitro in an attempt to enhance the effect of the drug. Liposomes were characterized from vesicle size, polydispersity index, and Zeta potential, and imaging by scanning electron microscopy. Antifungal assays were performed against Candida albicans, Candida tropicalis and Candida krusei by microdilution to determine the IC50 values and the viability curve. The Minimum Fungicidal Concentration (MFC) was performed by subcultivation in solid medium and the inhibitory effect of the association of TC and Fluconazole and tests to verify morphological changes was performed in micro-cultivation chambers based on concentrations on microdilution plates. The corresponding IC50 data of the substances ranged from 34.4 to 65249 μg/mL, considerably high values compared to the control (Fluconazole). The MFC of all compounds showing fungistatic effect. The performance of the compounds on the cell viability curve was similar in all tested strains, as they showed no antifungal potential when compared to the control (FCZ), when associated with FCZ they showed no significant antifungal activity. The free and liposomal TC also managed to restrict 100% of the fungal dimorphism, in both concentrations, against C. albicans, and against C. tropicalis the isolated TC did not show a significant inhibitory effect; however, against the C. krusei strain inhibited 100% in filamentous growth in both concentrations, which is statistically relevant. The liposomes were homogeneous, with vesicles with diameters of 185.46 nm for the control and 143.8 nm for the liposomal TC, and a surface charge potential of - 42.6 mV. By scanning microscopy, the spherical shapes of the vesicles were verified.
Collapse
|
6
|
Phan HT, Passos Gibson V, Guédin A, Ibarboure E, El Mammeri N, Grélard A, Le Meins JF, Dufourc EJ, Loquet A, Giasson S, Leblond Chain J. Switchable Lipids: From Conformational Switch to Macroscopic Changes in Lipid Vesicles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:3072-3082. [PMID: 36793207 DOI: 10.1021/acs.langmuir.2c03149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
It has been shown that the use of conformationally pH-switchable lipids can drastically enhance the cytosolic drug delivery of lipid vesicles. Understanding the process by which the pH-switchable lipids disturb the lipid assembly of nanoparticles and trigger the cargo release is crucial to optimize the rational design of pH-switchable lipids. Here, we gather morphological observations (FF-SEM, Cryo-TEM, AFM, confocal microscopy), physicochemical characterization (DLS, ELS), as well as phase behavior studies (DSC, 2H NMR, Langmuir isotherm, and MAS NMR) to propose a mechanism of pH-triggered membrane destabilization. We demonstrate that the switchable lipids are homogeneously incorporated with other co-lipids (DSPC, cholesterol, and DSPE-PEG2000) and promote a liquid-ordered phase insensitive to temperature variation. Upon acidification, the protonation of the switchable lipids triggers a conformational switch altering the self-assembly properties of lipid nanoparticles. These modifications do not lead to a phase separation of the lipid membrane; however, they cause fluctuations and local defects, which result in morphological changes of the lipid vesicles. These changes are proposed to affect the permeability of vesicle membrane, triggering the release of the cargo encapsulated in the lipid vesicles (LVs). Our results confirm that pH-triggered release does not require major morphological changes, but can result from small defects affecting the lipid membrane permeability.
Collapse
Affiliation(s)
- Huu Trong Phan
- Faculty of Pharmacy, University of Montreal, Montréal H3C 3J7, Canada
| | | | - Aurore Guédin
- University of Bordeaux, CNRS, INSERM, ARNA, UMR 5320, U1212, Bordeaux F-33000 France
| | - Emmanuel Ibarboure
- Laboratoire de Chimie des Polymères Organiques LCPO Université de Bordeaux CNRS Bordeaux INP UMR 5629, Pessac F-33600, France
| | - Nadia El Mammeri
- Institut de Chimie et de Biologie des Membranes et des Nano-objets, Institut Européen de Chimie et Biologie, CNRS, UMR 5248, Université de Bordeaux, Pessac F-33600, France
| | - Axelle Grélard
- Institut de Chimie et de Biologie des Membranes et des Nano-objets, Institut Européen de Chimie et Biologie, CNRS, UMR 5248, Université de Bordeaux, Pessac F-33600, France
| | - Jean-François Le Meins
- Laboratoire de Chimie des Polymères Organiques LCPO Université de Bordeaux CNRS Bordeaux INP UMR 5629, Pessac F-33600, France
| | - Erick J Dufourc
- Institut de Chimie et de Biologie des Membranes et des Nano-objets, Institut Européen de Chimie et Biologie, CNRS, UMR 5248, Université de Bordeaux, Pessac F-33600, France
| | - Antoine Loquet
- Institut de Chimie et de Biologie des Membranes et des Nano-objets, Institut Européen de Chimie et Biologie, CNRS, UMR 5248, Université de Bordeaux, Pessac F-33600, France
| | - Suzanne Giasson
- Faculty of Pharmacy, University of Montreal, Montréal H3C 3J7, Canada
- Department of Chemistry, University of Montreal, Montréal H3C 3J7, Canada
| | - Jeanne Leblond Chain
- University of Bordeaux, CNRS, INSERM, ARNA, UMR 5320, U1212, Bordeaux F-33000 France
| |
Collapse
|
7
|
Sugár IP. Interaction Energy between Two Separated Charged Spheres Surrounded Inside and Outside by Electrolyte. MEMBRANES 2022; 12:947. [PMID: 36295706 PMCID: PMC9610154 DOI: 10.3390/membranes12100947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 09/12/2022] [Accepted: 09/26/2022] [Indexed: 06/16/2023]
Abstract
By using the recently generalized version of Newton's shell theorem, analytical equations are derived to calculate the electric interaction energy between two separated, charged spheres surrounded outside and inside by electrolyte. This electric interaction energy is calculated as a function of the electrolyte's ion concentration, temperature, distance between the spheres and size of the spheres. At the same distance between the spheres, the absolute value of the interaction energy decreases with increasing electrolyte ion concentration and increases with increasing temperature. At zero electrolyte ion concentration, the derived analytical equation transforms into the Coulomb Equation Finally, the analytical equation is generalized to calculate the electric interaction energy of N separated, charged spheres surrounded by electrolyte.
Collapse
Affiliation(s)
- István P Sugár
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| |
Collapse
|
8
|
Karonen M. Insights into Polyphenol-Lipid Interactions: Chemical Methods, Molecular Aspects and Their Effects on Membrane Structures. PLANTS (BASEL, SWITZERLAND) 2022; 11:plants11141809. [PMID: 35890443 PMCID: PMC9317924 DOI: 10.3390/plants11141809] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 07/01/2022] [Accepted: 07/06/2022] [Indexed: 05/12/2023]
Abstract
Plant polyphenols have many potential applications, for example, in the fields of chemical ecology and human and animal health and nutrition. These biological benefits are related to their bioavailability, bioaccessibility and interactions with other biomolecules, such as proteins, lipids, fibers and amino acids. Polyphenol-protein interactions are well-studied, but less is known about their interactions with lipids and cell membranes. However, the affinity of polyphenols for lipid bilayers partially determines their biological activity and is also important from the usability perspective. The polyphenol-lipid interactions can be studied with several chemical tools including, among others, partition coefficient measurements, calorimetric methods, spectroscopic techniques and molecular dynamics simulation. Polyphenols can variably interact with and penetrate lipid bilayers depending on the structures and concentrations of the polyphenols, the compositions of the lipids and the ambient conditions and factors. Polyphenol penetrating the lipid bilayer can perturb and cause changes in its structure and biophysical properties. The current studies have used structurally different polyphenols, diverse model lipids and various measuring techniques. This approach provides detailed information on polyphenol-lipid interactions, but there is much variability, and the results may even be contradictory, for example, in relation to the locations and orientations of the polyphenols in the lipid bilayers. Nevertheless, by using well-characterized model polyphenols and lipids systematically and combining the results obtained with several techniques within a study, it is possible to create a good overall picture of these fascinating interactions.
Collapse
Affiliation(s)
- Maarit Karonen
- Natural Chemistry Research Group, Department of Chemistry, University of Turku, 20014 Turku, Finland
| |
Collapse
|
9
|
Unique and redundant spectral fingerprints of docosahexaenoic, alpha-linolenic and gamma-linolenic acids in binary mixtures. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.119222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
10
|
Sharma A, Seal A, Iyer SS, Srivastava A. Enthalpic and entropic contributions to interleaflet coupling drive domain registration and antiregistration in biological membrane. Phys Rev E 2022; 105:044408. [PMID: 35590589 DOI: 10.1103/physreve.105.044408] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Accepted: 03/14/2022] [Indexed: 06/15/2023]
Abstract
Biological membrane is a complex self-assembly of lipids, sterols, and proteins organized as a fluid bilayer of two closely stacked lipid leaflets. Differential molecular interactions among its diverse constituents give rise to heterogeneities in the membrane lateral organization. Under certain conditions, heterogeneities in the two leaflets can be spatially synchronized and exist as registered domains across the bilayer. Several contrasting theories behind mechanisms that induce registration of nanoscale domains have been suggested. Following a recent study showing the effect of position of lipid tail unsaturation on domain registration behavior, we decided to develop an analytical theory to elucidate the driving forces that create and maintain domain registry across leaflets. Towards this, we formulated a Hamiltonian for a stacked lattice system where site variables capture the lipid molecular properties such as the position of unsaturation and various other interactions that could drive phase separation and interleaflet coupling. We solve the Hamiltonian using Monte Carlo simulations and create a complete phase diagram that reports the presence or absence of registered domains as a function of various Hamiltonian parameters. We find that the interleaflet coupling should be described as a competing enthalpic contribution due to interaction of lipid tail termini, primarily due to saturated-saturated interactions, and an interleaflet entropic contribution from overlap of unsaturated tail termini. A higher position of unsaturation is seen to provide weaker interleaflet coupling. Thermodynamically stable nanodomains could also be observed for certain points in the parameter space in our bilayer model, which were further verified by carrying out extended Monte Carlo simulations. These persistent noncoalescing registered nanodomains close to the lower end of the accepted nanodomain size range also point towards a possible "nanoscale" emulsion description of lateral heterogeneities in biological membrane leaflets.
Collapse
Affiliation(s)
- Akshara Sharma
- Department of Physics, Indian Institute of Science-Bangalore, C. V. Raman Road, Bangalore, Karnataka 560012, India
| | - Aniruddha Seal
- School of Chemical Sciences, National Institute of Science Education and Research, Bhubaneswar, Khurda, Odisha 752050, India
| | - Sahithya S Iyer
- Molecular Biophysics Unit, Indian Institute of Science-Bangalore, C. V. Raman Road, Bangalore, Karnataka 560012, India
| | - Anand Srivastava
- Molecular Biophysics Unit, Indian Institute of Science-Bangalore, C. V. Raman Road, Bangalore, Karnataka 560012, India
| |
Collapse
|
11
|
Sofińska K, Lupa D, Chachaj-Brekiesz A, Czaja M, Kobierski J, Seweryn S, Skirlińska-Nosek K, Szymonski M, Wilkosz N, Wnętrzak A, Lipiec E. Revealing local molecular distribution, orientation, phase separation, and formation of domains in artificial lipid layers: Towards comprehensive characterization of biological membranes. Adv Colloid Interface Sci 2022; 301:102614. [PMID: 35190313 DOI: 10.1016/j.cis.2022.102614] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 01/28/2022] [Accepted: 02/01/2022] [Indexed: 01/01/2023]
Abstract
Lipids, together with molecules such as DNA and proteins, are one of the most relevant systems responsible for the existence of life. Selected lipids are able to assembly into various organized structures, such as lipid membranes. The unique properties of lipid membranes determine their complex functions, not only to separate biological environments, but also to participate in regulatory functions, absorption of nutrients, cell-cell communication, endocytosis, cell signaling, and many others. Despite numerous scientific efforts, still little is known about the reason underlying the variability within lipid membranes, and its biochemical significance. In this review, we discuss the structural complexity of lipid membranes, as well as the importance to simplify studied systems in order to understand phenomena occurring in natural, complex membranes. Such systems require a model interface to be analyzed. Therefore, here we focused on analytical studies of artificial systems at various interfaces. The molecular structure of lipid membranes, specifically the nanometric thickens of molecular bilayer, limits in a major extent the choice of highly sensitive methods suitable to study such structures. Therefore, we focused on methods that combine high sensitivity, and/or chemical selectivity, and/or nanometric spatial resolution, such as atomic force microscopy, nanospectroscopy (tip-enhanced Raman spectroscopy, infrared nanospectroscopy), phase modulation infrared reflection-absorption spectroscopy, sum-frequency generation spectroscopy. We summarized experimental and theoretical approaches providing information about molecular structure and composition, lipid spatial distribution (phase separation), organization (domain shape, molecular orientation) of lipid membranes, and real-time visualization of the influence of various molecules (proteins, drugs) on their integrity. An integral part of this review discusses the latest achievements in the field of lipid layer-based biosensors.
Collapse
|
12
|
Nieto-Garai JA, Lorizate M, Contreras FX. Shedding light on membrane rafts structure and dynamics in living cells. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2022; 1864:183813. [PMID: 34748743 DOI: 10.1016/j.bbamem.2021.183813] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 10/21/2021] [Accepted: 10/25/2021] [Indexed: 12/12/2022]
Abstract
Cellular membranes are fundamental building blocks regulating an extensive repertoire of biological functions. These structures contain lipids and membrane proteins that are known to laterally self-aggregate in the plane of the membrane, forming defined membrane nanoscale domains essential for protein activity. Membrane rafts are described as heterogeneous, dynamic, and short-lived cholesterol- and sphingolipid-enriched membrane nanodomains (10-200 nm) induced by lipid-protein and lipid-lipid interactions. Those membrane nanodomains have been extensively characterized using model membranes and in silico methods. However, despite the development of advanced fluorescence microscopy techniques, undoubted nanoscale visualization by imaging techniques of membrane rafts in the membrane of unperturbed living cells is still uncompleted, increasing the skepticism about their existence. Here, we broadly review recent biochemical and microscopy techniques used to investigate membrane rafts in living cells and we enumerate persistent open questions to answer before unlocking the mystery of membrane rafts in living cells.
Collapse
Affiliation(s)
- Jon Ander Nieto-Garai
- Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), Barrio Sarriena s/n, 48940 Bilbao, Spain.
| | - Maier Lorizate
- Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), Barrio Sarriena s/n, 48940 Bilbao, Spain; Instituto Biofisika (UPV/EHU, CSIC), Barrio Sarriena s/n, 48940 Bilbao, Spain
| | - F-Xabier Contreras
- Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), Barrio Sarriena s/n, 48940 Bilbao, Spain; Instituto Biofisika (UPV/EHU, CSIC), Barrio Sarriena s/n, 48940 Bilbao, Spain; IKERBASQUE, Basque Foundation for Science, 48011 Bilbao, Spain.
| |
Collapse
|
13
|
Abstract
The ability of cholesterol to uncoil (i.e., condense) the acyl chains of phospholipids has been known for a century. Despite extensive studies of the interactions between cholesterol and phospholipids, a molecular-level understanding of this uncoiling phenomenon has remained elusive. Equally unclear has been whether cholesterol's two different faces (i.e., its relatively smooth α face and its relatively rough β face) contribute to its condensing power. Because cholesterol's condensing effect is believed to play a major role in controlling the fluidity, structure, and functioning of all animal cell membranes, its biological importance cannot be overstated. This Perspective focuses on experimental evidence that addresses (i) the credibility of a popular "umbrella" mechanism that has been used to account for cholesterol's condensing effect, (ii) the credibility of an alternate "template" mechanism, (iii) the importance of cholesterol two-faced character with respect to its condensing power, and (iv) the viability of a surface occupancy model.
Collapse
|
14
|
Lewandowski D, Sander CL, Tworak A, Gao F, Xu Q, Skowronska-Krawczyk D. Dynamic lipid turnover in photoreceptors and retinal pigment epithelium throughout life. Prog Retin Eye Res 2021; 89:101037. [PMID: 34971765 PMCID: PMC10361839 DOI: 10.1016/j.preteyeres.2021.101037] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 12/13/2021] [Accepted: 12/15/2021] [Indexed: 12/13/2022]
Abstract
The retinal pigment epithelium-photoreceptor interphase is renewed each day in a stunning display of cellular interdependence. While photoreceptors use photosensitive pigments to convert light into electrical signals, the RPE supports photoreceptors in their function by phagocytizing shed photoreceptor tips, regulating the blood retina barrier, and modulating inflammatory responses, as well as regenerating the 11-cis-retinal chromophore via the classical visual cycle. These processes involve multiple protein complexes, tightly regulated ligand-receptors interactions, and a plethora of lipids and protein-lipids interactions. The role of lipids in maintaining a healthy interplay between the RPE and photoreceptors has not been fully delineated. In recent years, novel technologies have resulted in major advancements in understanding several facets of this interplay, including the involvement of lipids in phagocytosis and phagolysosome function, nutrient recycling, and the metabolic dependence between the two cell types. In this review, we aim to integrate the complex role of lipids in photoreceptor and RPE function, emphasizing the dynamic exchange between the cells as well as discuss how these processes are affected in aging and retinal diseases.
Collapse
Affiliation(s)
- Dominik Lewandowski
- Department of Ophthalmology, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, USA
| | - Christopher L Sander
- Department of Ophthalmology, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, USA; Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Aleksander Tworak
- Department of Ophthalmology, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, USA
| | - Fangyuan Gao
- Department of Ophthalmology, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, USA
| | - Qianlan Xu
- Department of Physiology and Biophysics, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, USA; Department of Ophthalmology, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, USA
| | - Dorota Skowronska-Krawczyk
- Department of Physiology and Biophysics, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, USA; Department of Ophthalmology, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, USA.
| |
Collapse
|
15
|
Kishimoto T, Mioka T, Itoh E, Williams DE, Andersen RJ, Tanaka K. Phospholipid flippases and Sfk1 are essential for the retention of ergosterol in the plasma membrane. Mol Biol Cell 2021; 32:1374-1392. [PMID: 34038161 PMCID: PMC8694040 DOI: 10.1091/mbc.e20-11-0699] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 05/18/2021] [Accepted: 05/21/2021] [Indexed: 11/17/2022] Open
Abstract
Sterols are important lipid components of the plasma membrane (PM) in eukaryotic cells, but it is unknown how the PM retains sterols at a high concentration. Phospholipids are asymmetrically distributed in the PM, and phospholipid flippases play an important role in generating this phospholipid asymmetry. Here, we provide evidence that phospholipid flippases are essential for retaining ergosterol in the PM of yeast. A mutant in three flippases, Dnf1-Lem3, Dnf2-Lem3, and Dnf3-Crf1, and a membrane protein, Sfk1, showed a severe growth defect. We recently identified Sfk1 as a PM protein involved in phospholipid asymmetry. The PM of this mutant showed high permeability and low density. Staining with the sterol probe filipin and the expression of a sterol biosensor revealed that ergosterol was not retained in the PM. Instead, ergosterol accumulated in an esterified form in lipid droplets. We propose that ergosterol is retained in the PM by the asymmetrical distribution of phospholipids and the action of Sfk1. Once phospholipid asymmetry is severely disrupted, sterols might be exposed on the cytoplasmic leaflet of the PM and actively transported to the endoplasmic reticulum by sterol transfer proteins.
Collapse
Affiliation(s)
- Takuma Kishimoto
- Division of Molecular Interaction, Institute for Genetic Medicine, Hokkaido University Graduate School of Life Science, Sapporo, Hokkaido 060-0815, Japan
| | - Tetsuo Mioka
- Division of Molecular Interaction, Institute for Genetic Medicine, Hokkaido University Graduate School of Life Science, Sapporo, Hokkaido 060-0815, Japan
| | - Eriko Itoh
- Division of Molecular Interaction, Institute for Genetic Medicine, Hokkaido University Graduate School of Life Science, Sapporo, Hokkaido 060-0815, Japan
| | - David E. Williams
- Departments of Chemistry and Earth, Ocean, and Atmospheric Sciences, University of British Columbia, Vancouver, BC V6T 1Z1, Canada
| | - Raymond J. Andersen
- Departments of Chemistry and Earth, Ocean, and Atmospheric Sciences, University of British Columbia, Vancouver, BC V6T 1Z1, Canada
| | - Kazuma Tanaka
- Division of Molecular Interaction, Institute for Genetic Medicine, Hokkaido University Graduate School of Life Science, Sapporo, Hokkaido 060-0815, Japan
| |
Collapse
|
16
|
ESCRT-III induces phase separation in model membranes prior to budding and causes invagination of the liquid-ordered phase. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2021; 1863:183689. [PMID: 34224704 DOI: 10.1016/j.bbamem.2021.183689] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 06/05/2021] [Accepted: 06/27/2021] [Indexed: 11/21/2022]
Abstract
Membrane fission triggered by the endosomal sorting complex required for transport (ESCRT) is an important process observed in several pathogenic and non-pathogenic cellular events. From a synthetic-biology viewpoint, ESCRT proteins represent an interesting machinery for the construction of cell mimetic sub-compartments produced by fission. Since their discovery, the studies on ESCRT-III-mediated action, have mainly focused on protein dynamics, ignoring the role of lipid organization and membrane phase state. Recently, it has been suggested that membrane buds formed by the action of ESCRT-III are generated from transient microdomains in endosomal membranes. However, the interplay between membrane domain formation and ESCRT remodeling pathways has not been investigated. Here, giant unilamellar vesicles made of ternary lipid mixtures, either homogeneous in phase or exhibiting liquid-ordered/liquid-disordered phase coexistence, were employed as a model membrane system. These vesicles were incubated with purified recombinant ESCRT-III proteins from the parasite Entamoeba histolytica. In homogeneous membranes, we observe that EhVps32 can trigger domain formation while EhVps20 preferentially co-localizes in the liquid disordered phase. The addition of EhVps24 appears to induce the formation of intraluminal vesicles produced from the liquid-ordered phase. In phase separated membranes, the intraluminal vesicles are also generated from the liquid-ordered phase and presumably emerge from the phase boundary region. Our findings reinforce the hypothesis that ESCRT-mediated remodeling depends on the membrane phase state. Furthermore, the obtained results point to a potential synthetic biology approach for establishing eukaryotic mimics of artificial cells with microcompartments of specific membrane composition, which can also differ from that of the mother vesicle.
Collapse
|
17
|
Feigenson GW. On the small size of liquid-disordered + liquid-ordered nanodomains. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2021; 1863:183685. [PMID: 34175299 DOI: 10.1016/j.bbamem.2021.183685] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Revised: 06/09/2021] [Accepted: 06/17/2021] [Indexed: 11/15/2022]
Abstract
Four-component phase diagrams reveal that Liquid-disordered + liquid-ordered (Ld + Lo) nanodomains are exclusively found adjacent to a three-phase region, and so cannot be a one-phase microemulsion. Of importance for understanding biological membranes, a small change in lipid bilayer composition can change the size of these coexisting phase domains hundreds of fold, between tens of nanometers and microns. Nanodomain diameter, measured from small angle neutron scattering, is in the range 15-35 nm, consistent with stabilization by repulsive dipole fields. Ld/Lo line tension controls the Ld + Lo domain size transition. Other than size, chemical and physical properties of the phase domains do not seem to change during the transition. Unfavorable lipid-lipid pairwise interactions, rather than phase thickness mismatch, seem to be the main reason for Ld + Lo immiscibility. Pairwise interactions of cholesterol-phospholipid seem to be favorable, whereas pairwise interactions of high-melting phospholipid with low-melting phospholipid are unfavorable. Measured Ld/Lo line tension, like the phase separation, is created mainly by unfavorable lipid-lipid pairwise interactions. Lipid dipole-dipole repulsion opposes these unfavorable lipid-lipid pairwise interactions and thus, in a sense, is the reason that nanodomains form. Bilayer physical and chemical properties measured from macroscopic domains of coexisting Ld + Lo phases should be good approximations for the properties of coexisting nanoscopic domains.
Collapse
Affiliation(s)
- Gerald W Feigenson
- Cornell University Department of Molecular Biology and Genetics, Room 201 Biotechnology Building, 215 Tower Rd. Ithaca, New York 14853, United States.
| |
Collapse
|
18
|
Dynamic "Molecular Portraits" of Biomembranes Drawn by Their Lateral Nanoscale Inhomogeneities. Int J Mol Sci 2021; 22:ijms22126250. [PMID: 34200697 PMCID: PMC8230387 DOI: 10.3390/ijms22126250] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 06/04/2021] [Accepted: 06/09/2021] [Indexed: 01/22/2023] Open
Abstract
To date, it has been reliably shown that the lipid bilayer/water interface can be thoroughly characterized by a sophisticated so-called "dynamic molecular portrait". The latter reflects a combination of time-dependent surface distributions of various physicochemical properties, inherent in both model lipid bilayers and natural multi-component cell membranes. One of the most important features of biomembranes is their mosaicity, which is expressed in the constant presence of lateral inhomogeneities, the sizes and lifetimes of which vary in a wide range-from 1 to 103 nm and from 0.1 ns to milliseconds. In addition to the relatively well-studied macroscopic domains (so-called "rafts"), the analysis of micro- and nanoclusters (or domains) that form an instantaneous picture of the distribution of structural, dynamic, hydrophobic, electrical, etc., properties at the membrane-water interface is attracting increasing interest. This is because such nanodomains (NDs) have been proven to be crucial for the proper membrane functioning in cells. Therefore, an understanding with atomistic details the phenomena associated with NDs is required. The present mini-review describes the recent results of experimental and in silico studies of spontaneously formed NDs in lipid membranes. The main attention is paid to the methods of ND detection, characterization of their spatiotemporal parameters, the elucidation of the molecular mechanisms of their formation. Biological role of NDs in cell membranes is briefly discussed. Understanding such effects creates the basis for rational design of new prospective drugs, therapeutic approaches, and artificial membrane materials with specified properties.
Collapse
|
19
|
Abstract
Fungal pathologies caused by the genus Candida have increased in recent years due to the involvement of immunosuppressed people and the advance of resistance mechanisms acquired by these microorganisms. Liposomes are nanovesicles with lipid bilayers in which they store compounds. α-Bisabolol is a sesquiterpene with proven biological activities, and in this work it was tested alone in liposomes and in association with Fluconazole in vitro to evaluate the antifungal potential, Fluconazole optimization, and virulence inhibitory effect in vitro. Antifungal assays were performed against standard strains of Candida albicans, Candida tropicalis, and Candida krusei by microdilution to identify the IC50 values and to obtain the cell viability. The Minimum Fungicidal Concentration (MFC) was performed by subculturing on the solid medium, and at their subinhibitory concentration (Matrix Concentration (MC): 16,384 µg/mL) (MC/16), the compounds, both isolated and liposomal, were associated with fluconazole in order to verify the inhibitory effect of this junction. Tests to ascertain changes in morphology were performed in microculture chambers according to MC concentrations. Liposomes were characterized from the vesicle size, polydispersity index, average Zeta potential, and scanning electron microscopy. The IC50 value of the liposomal bisabolol associated with fluconazole (FCZ) was 2.5 µg/mL against all strains tested, revealing a potentiating effect. Liposomal bisabolol was able to potentiate the effect of fluconazole against the CA and CT strains by reducing its concentration and completely inhibiting fungal growth. α-Bisabolol in liposomal form inhibited the morphological transition in all strains tested at a concentration of MC/8. The liposomes were homogeneous, with vesicles with diameters of 203.8 nm for the liposomal bisabolol and a surface charge potential of −34.2 mV, conferring stability to the nanosystem. Through scanning microscopy, the spherical shapes of the vesicles were observed.
Collapse
|
20
|
Kobierski J, Wnętrzak A, Chachaj-Brekiesz A, Filiczkowska A, Petelska AD, Dynarowicz-Latka P. How the replacement of cholesterol by 25-hydroxycholesterol affects the interactions with sphingolipids: The Langmuir Monolayer Study complemented with theoretical calculations. J R Soc Interface 2021; 18:20210050. [PMID: 33726539 DOI: 10.1098/rsif.2021.0050] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
In this paper, a representative of chain-oxidized sterols, 25-hydroxycholesterol (25-OH), has been studied in Langmuir monolayers mixed with the sphingolipids sphingomyelin (SM) and ganglioside (GM1) to build lipid rafts. A classical Langmuir monolayer approach based on thermodynamic analysis of interactions was complemented with microscopic visualization of films (Brewster angle microscopy), surface-sensitive spectroscopy (polarization modulation-infrared reflection-absorption spectroscopy) and theoretical calculations (density functional theory modelling and molecular dynamics simulations). Strong interactions between 25-OH and both investigated sphingolipids enabled the formation of surface complexes. As known from previous studies, 25-OH in pure monolayers can be anchored to the water surface with a hydroxyl group at either C(3) or C(25). In this study, we investigated how the presence of additional strong interactions with sphingolipids modifies the surface arrangement of 25-OH. Results have shown that, in the 25-OH/GM1 system, there are no preferences regarding the orientation of the 25-OH molecule in surface complexes and two types of complexes are formed. On the other hand, SM enforces one specific orientation of 25-OH: being anchored with the C(3)-OH group to the water. The strength of interactions between the studied sphingolipids and 25-OH versus cholesterol is similar, which indicates that cholesterol may well be replaced by oxysterol in the lipid raft system. In this way, the composition of lipid rafts can be modified, changing their rheological properties and, as a consequence, influencing their proper functioning.
Collapse
Affiliation(s)
- Jan Kobierski
- Department of Pharmaceutical Biophysics, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9, 30-688 Kraków, Poland
| | - Anita Wnętrzak
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Kraków, Poland
| | - Anna Chachaj-Brekiesz
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Kraków, Poland
| | - Anna Filiczkowska
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, Łojasiewicza 11, 30-348 Kraków, Poland
| | - Aneta D Petelska
- Faculty of Chemistry, University of Bialystok, Ciołkowskiego 1 K, 15-425 Bialystok, Poland
| | | |
Collapse
|
21
|
Sugár IP. Electric energies of a charged sphere surrounded by electrolyte. AIMS BIOPHYSICS 2021. [DOI: 10.3934/biophy.2021012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
|
22
|
Yang J, Jin J, Li S. Role of polyunsaturated phospholipids in liquid-ordered and liquid-disordered phases. RSC Adv 2021; 11:27115-27120. [PMID: 35480686 PMCID: PMC9037819 DOI: 10.1039/d1ra02692e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 07/30/2021] [Indexed: 11/21/2022] Open
Abstract
Polyunsaturated phospholipids play a strong repulsive role in the liquid-disordered phase but a weak role in the liquid-ordered phase.
Collapse
Affiliation(s)
- Jing Yang
- College of Education, Wenzhou University, Wenzhou, Zhejiang 325035, China
| | - Jianyu Jin
- College of Education, Wenzhou University, Wenzhou, Zhejiang 325035, China
| | - Shiben Li
- Department of Physics, Wenzhou University, Wenzhou, Zhejiang 325035, China
| |
Collapse
|
23
|
Mamode Cassim A, Grison M, Ito Y, Simon-Plas F, Mongrand S, Boutté Y. Sphingolipids in plants: a guidebook on their function in membrane architecture, cellular processes, and environmental or developmental responses. FEBS Lett 2020; 594:3719-3738. [PMID: 33151562 DOI: 10.1002/1873-3468.13987] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 10/29/2020] [Accepted: 10/30/2020] [Indexed: 12/15/2022]
Abstract
Sphingolipids are fundamental lipids involved in various cellular, developmental and stress-response processes. As such, they orchestrate not only vital molecular mechanisms of living cells but also act in diseases, thus qualifying as potential pharmaceutical targets. Sphingolipids are universal to eukaryotes and are also present in some prokaryotes. Some sphingolipid structures are conserved between animals, plants and fungi, whereas others are found only in plants and fungi. In plants, the structural diversity of sphingolipids, as well as their downstream effectors and molecular and cellular mechanisms of action, are of tremendous interest to both basic and applied researchers, as about half of all small molecules in clinical use originate from plants. Here, we review recent advances towards a better understanding of the biosynthesis of sphingolipids, the diversity in their structures as well as their functional roles in membrane architecture, cellular processes such as membrane trafficking and cell polarity, and cell responses to environmental or developmental signals.
Collapse
Affiliation(s)
- Adiilah Mamode Cassim
- Agroécologie, AgroSup Dijon, INRAE, ERL 6003 CNRS, University of Bourgogne Franche-Comté, Dijon, France
| | - Magali Grison
- Laboratoire de Biogenèse Membranaire, UMR5200, Université de Bordeaux, CNRS, Villenave d'Ornon, France
| | - Yoko Ito
- Laboratoire de Biogenèse Membranaire, UMR5200, Université de Bordeaux, CNRS, Villenave d'Ornon, France
| | - Francoise Simon-Plas
- Agroécologie, AgroSup Dijon, INRAE, ERL 6003 CNRS, University of Bourgogne Franche-Comté, Dijon, France
| | - Sébastien Mongrand
- Laboratoire de Biogenèse Membranaire, UMR5200, Université de Bordeaux, CNRS, Villenave d'Ornon, France
| | - Yohann Boutté
- Laboratoire de Biogenèse Membranaire, UMR5200, Université de Bordeaux, CNRS, Villenave d'Ornon, France
| |
Collapse
|
24
|
Canepa E, Salassi S, de Marco AL, Lambruschini C, Odino D, Bochicchio D, Canepa F, Canale C, Dante S, Brescia R, Stellacci F, Rossi G, Relini A. Amphiphilic gold nanoparticles perturb phase separation in multidomain lipid membranes. NANOSCALE 2020; 12:19746-19759. [PMID: 32966489 DOI: 10.1039/d0nr05366j] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Amphiphilic gold nanoparticles with diameters in the 2-4 nm range are promising as theranostic agents thanks to their spontaneous translocation through cell membranes. This study addresses the effects that these nanoparticles may have on a distinct feature of plasma membranes: lipid lateral phase separation. Atomic force microscopy, quartz crystal microbalance, and molecular dynamics are combined to study the interaction between model neuronal membranes, which spontaneously form ordered and disordered lipid domains, and amphiphilic gold nanoparticles having negatively charged surface functionalization. Nanoparticles are found to interact with the bilayer and form bilayer-embedded ordered aggregates. Nanoparticles also suppress lipid phase separation, in a concentration-dependent fashion. A general, yet simple thermodynamic model is developed to show that the change of lipid-lipid enthalpy is the dominant driving force towards the nanoparticle-induced destabilization of phase separation.
Collapse
Affiliation(s)
- Ester Canepa
- Department of Chemistry and Industrial Chemistry, University of Genoa, Via Dodecaneso 31, 16146 Genoa, Italy.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
25
|
Luo Y, Maibaum L. Modulated and spiral surface patterns on deformable lipid vesicles. J Chem Phys 2020; 153:144901. [PMID: 33086800 DOI: 10.1063/5.0020087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
We investigate the behavior of two-dimensional systems that exhibit a transition between homogeneous and spatially inhomogeneous phases, which have spherical topology, and whose mechanical properties depend on the local value of the order parameter. One example of such a system is multicomponent lipid bilayer vesicles, which serve as a model to study cellular membranes. Under certain conditions, such bilayers separate into coexisting liquid-ordered and liquid-disordered regions. When arranged into the shape of small vesicles, this phase coexistence can result in spatial patterns that are more complex than the basic two-domain configuration encountered in typical bulk systems. The difference in bending rigidity between the liquid-ordered and liquid-disordered regions couples the shape of the vesicle to the local composition. We show that this interplay gives rise to a rich phase diagram that includes homogeneous, separated, and axisymmetric modulated phases that are divided by regions of spiral patterns in the surface morphology.
Collapse
Affiliation(s)
- Yongtian Luo
- Department of Chemistry, University of Washington, Seattle, Washington 98195, USA
| | - Lutz Maibaum
- Department of Chemistry, University of Washington, Seattle, Washington 98195, USA
| |
Collapse
|
26
|
Radja A. Pollen wall patterns as a model for biological self-assembly. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2020; 336:629-641. [PMID: 32991047 PMCID: PMC9292386 DOI: 10.1002/jez.b.23005] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 08/26/2020] [Accepted: 08/28/2020] [Indexed: 12/21/2022]
Abstract
We are still far from being able to predict organisms' shapes purely from their genetic codes. While it is imperative to identify which encoded macromolecules contribute to a phenotype, determining how macromolecules self-assemble independently of the genetic code may be equally crucial for understanding shape development. Pollen grains are typically single-celled microgametophytes that have decorated walls of various shapes and patterns. The accumulation of morphological data and a comprehensive understanding of the wall development makes this system ripe for mathematical and physical modeling. Therefore, pollen walls are an excellent system for identifying both the genetic products and the physical processes that result in a huge diversity of extracellular morphologies. In this piece, I highlight the current understanding of pollen wall biology relevant for quantification studies and enumerate the modellable aspects of pollen wall patterning and specific approaches that one may take to elucidate how pollen grains build their beautifully patterned walls.
Collapse
Affiliation(s)
- Asja Radja
- School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts, USA
| |
Collapse
|
27
|
Li M, Heller WT, Liu CH, Gao CY, Cai Y, Hou Y, Nieh MP. Effects of fluidity and charge density on the morphology of a bicellar mixture - A SANS study. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183315. [PMID: 32304755 DOI: 10.1016/j.bbamem.2020.183315] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 04/11/2020] [Accepted: 04/13/2020] [Indexed: 01/28/2023]
Abstract
The spontaneously formed structures of physiologically relevant lipid model membranes made of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine, 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-(1'-rac-glycerol) and 1,2-hexanoyl-sn-glycero-3-phosphocholine have been evaluated in depth using small angle neutron scattering. Although a common molar ratio of long- to short- chain phospholipids (~4) as reported in many bicellar mixtures was used, discoidal bicelles were not found as the major phase throughout the range of lipid concentration and temperature studied, indicating that the required condition for the formation of bicelle is the immiscibility between the long- and short- chain lipids, which were in the gel and Lα phases, respectively, in previous reports. In this study, all lipids are in the Lα phase. The characterization outcome suggests that the spontaneous structures tie strongly with the physical parameters of the system such as melting transition temperature of the long-chain lipid, total lipid concentration and charge density of the system. Multilamellar vesicles, unilamellar vesicles, ribbons and perforated lamellae can be obtained based on the analysis of the small angle neutron scattering results, leading to the construction of structural diagrams. This report provides the important map to choose suitable lipid systems for the structural study of membrane-associated proteins, design of theranostic nanocarriers or other related research fields.
Collapse
Affiliation(s)
- Ming Li
- Polymer Program, Institute of Materials Science, University of Connecticut, Storrs, 06269, USA
| | - William T Heller
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Chung-Hao Liu
- Polymer Program, Institute of Materials Science, University of Connecticut, Storrs, 06269, USA
| | - Carrie Y Gao
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Yutian Cai
- Department of Polymer Material Science and Engineering, College of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha, Hunan 410000, China
| | - Yiming Hou
- Department of Polymer Material Science and Engineering, College of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha, Hunan 410000, China
| | - Mu-Ping Nieh
- Polymer Program, Institute of Materials Science, University of Connecticut, Storrs, 06269, USA; Department of Chemical & Biomolecular Engineering, University of Connecticut, Storrs 06269, USA; Department of Biomedical Engineering, University of Connecticut, Storrs 06269, USA.
| |
Collapse
|
28
|
Cruz MAE, Ferreira CR, Tovani CB, de Oliveira FA, Bolean M, Caseli L, Mebarek S, Millán JL, Buchet R, Bottini M, Ciancaglini P, Paula Ramos A. Phosphatidylserine controls calcium phosphate nucleation and growth on lipid monolayers: A physicochemical understanding of matrix vesicle-driven biomineralization. J Struct Biol 2020; 212:107607. [PMID: 32858148 DOI: 10.1016/j.jsb.2020.107607] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 08/15/2020] [Accepted: 08/19/2020] [Indexed: 12/12/2022]
Abstract
Bone biomineralization is an exquisite process by which a hierarchically organized mineral matrix is formed. Growing evidence has uncovered the involvement of one class of extracellular vesicles, named matrix vesicles (MVs), in the formation and delivery of the first mineral nuclei to direct collagen mineralization. MVs are released by mineralization-competent cells equipped with a specific biochemical machinery to initiate mineral formation. However, little is known about the mechanisms by which MVs can trigger this process. Here, we present a combination of in situ investigations and ex vivo analysis of MVs extracted from growing-femurs of chicken embryos to investigate the role played by phosphatidylserine (PS) in the formation of mineral nuclei. By using self-assembled Langmuir monolayers, we reconstructed the nucleation core - a PS-enriched motif thought to trigger mineral formation in the lumen of MVs. In situ infrared spectroscopy of Langmuir monolayers and ex situ analysis by transmission electron microscopy evidenced that mineralization was achieved in supersaturated solutions only when PS was present. PS nucleated amorphous calcium phosphate that converted into biomimetic apatite. By using monolayers containing lipids extracted from native MVs, mineral formation was also evidenced in a manner that resembles the artificial PS-enriched monolayers. PS-enrichment in lipid monolayers creates nanodomains for local increase of supersaturation, leading to the nucleation of ACP at the interface through a multistep process. We posited that PS-mediated nucleation could be a predominant mechanism to produce the very first mineral nuclei during MV-driven bone/cartilage biomineralization.
Collapse
Affiliation(s)
- Marcos A E Cruz
- Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, FFCLRP - Universidade de São Paulo - Departamento de Química, Brazil
| | - Claudio R Ferreira
- Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, FFCLRP - Universidade de São Paulo - Departamento de Química, Brazil
| | - Camila B Tovani
- Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, FFCLRP - Universidade de São Paulo - Departamento de Química, Brazil
| | | | - Maytê Bolean
- Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, FFCLRP - Universidade de São Paulo - Departamento de Química, Brazil
| | - Luciano Caseli
- Institute of Environmental, Chemical and Pharmaceutical Sciences - Federal University of Sao Paulo, Brazil
| | - Saida Mebarek
- Universite de Lyon, ICBMS UMR 5246 CNRS, Villeurbanne, France
| | - José Luis Millán
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
| | - Rene Buchet
- Universite de Lyon, ICBMS UMR 5246 CNRS, Villeurbanne, France
| | - Massimo Bottini
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA; Department of Experimental Medicine, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Pietro Ciancaglini
- Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, FFCLRP - Universidade de São Paulo - Departamento de Química, Brazil.
| | - Ana Paula Ramos
- Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, FFCLRP - Universidade de São Paulo - Departamento de Química, Brazil.
| |
Collapse
|
29
|
Iyer SS, Srivastava A. Degeneracy in molecular scale organization of biological membranes. SOFT MATTER 2020; 16:6752-6764. [PMID: 32628232 DOI: 10.1039/d0sm00619j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The scale-rich spatiotemporal organization in biological membranes has its origin in the differential inter- and intra-molecular interactions among their constituents. In this work, we explore the molecular-origin behind that variety and possible degeneracy in lateral organization in membranes. For our study, we post-process microsecond long all-atom molecular dynamics trajectories for three systems that exhibit fluid phase coexistence: (i) PSM/POPC/Chol (0.47/0.32/0.21), (ii) PSM/DOPC/Chol (0.43/0.38/0.19) and (iii) DPPC/DOPC/Chol (0.37/0.36/0.27). To distinguish the liquid ordered and disordered regions at molecular scales, we calculate the degree of non-affineness of individual lipids in their neighbourhood and track their topological rearrangements. Disconnectivity graph analysis with respect to membrane organization shows that the DPPC/DOPC/Chol and PSM/DOPC/Chol systems exhibit funnel-like energy landscapes as opposed to a highly frustrated energy landscape for the more biomimetic PSM/POPC/Chol system. We use these measurements to develop a continuous lattice Hamiltonian and evolve that using Monte Carlo simulated annealing to explore the possibility of structural degeneracy in membrane organization. Our data show that model membranes with lipid constituents that are biomimetic (PSM/POPC/Chol) have the ability to access a large range of membrane sub-structure space (higher degeneracy) as compared to the other two systems, which form only one kind of substructure even with changing composition. Since the spatiotemporal organization in biological membranes dictates the "molecular encounters" and in turn larger scale biological processes such as molecular transport, trafficking and cellular signalling, we posit that this structural degeneracy could enable access to a larger repository to functionally important molecular organization in systems with physiologically relevant compositions.
Collapse
Affiliation(s)
- Sahithya S Iyer
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India.
| | | |
Collapse
|
30
|
Huang J, Hiraki S, Feigenson GW. Calculation of Liquid-Disordered/Liquid-Ordered Line Tension from Pairwise Lipid Interactions. J Phys Chem B 2020; 124:4949-4959. [DOI: 10.1021/acs.jpcb.0c03329] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- J. Huang
- Department of Physics and Astronomy, Texas Tech University, Box 41051, Lubbock, Texas 79409, United States
| | - S. Hiraki
- Department of Chemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, Japan
| | - G. W. Feigenson
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853, United States
| |
Collapse
|
31
|
Levental KR, Malmberg E, Symons JL, Fan YY, Chapkin RS, Ernst R, Levental I. Lipidomic and biophysical homeostasis of mammalian membranes counteracts dietary lipid perturbations to maintain cellular fitness. Nat Commun 2020; 11:1339. [PMID: 32165635 PMCID: PMC7067841 DOI: 10.1038/s41467-020-15203-1] [Citation(s) in RCA: 105] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 02/21/2020] [Indexed: 11/29/2022] Open
Abstract
Proper membrane physiology requires maintenance of biophysical properties, which must be buffered from external perturbations. While homeostatic adaptation of membrane fluidity to temperature variation is a ubiquitous feature of ectothermic organisms, such responsive membrane adaptation to external inputs has not been directly observed in mammals. Here, we report that challenging mammalian membranes by dietary lipids leads to robust lipidomic remodeling to preserve membrane physical properties. Specifically, exogenous polyunsaturated fatty acids are rapidly incorporated into membrane lipids, inducing a reduction in membrane packing. These effects are rapidly compensated both in culture and in vivo by lipidome-wide remodeling, most notably upregulation of saturated lipids and cholesterol, resulting in recovery of membrane packing and permeability. Abrogation of this response results in cytotoxicity when membrane homeostasis is challenged by dietary lipids. These results reveal an essential mammalian mechanism for membrane homeostasis wherein lipidome remodeling in response to dietary lipid inputs preserves functional membrane phenotypes. Proper membrane physiology requires maintenance of a narrow range of physicochemical properties, which must be buffered from external perturbations. Here, authors report lipidomic remodeling to preserve membrane physical properties upon exogenous polyunsaturated fatty acids exposure.
Collapse
Affiliation(s)
- Kandice R Levental
- Department of Integrative Biology & Pharmacology, University of Texas Health Science Center at Houston, Houston, TX, USA.
| | - Eric Malmberg
- Department of Integrative Biology & Pharmacology, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Jessica L Symons
- Department of Integrative Biology & Pharmacology, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Yang-Yi Fan
- Program in Integrative Nutrition & Complex Diseases and Department of Nutrition, Texas A&M University, College Station, TX, USA
| | - Robert S Chapkin
- Program in Integrative Nutrition & Complex Diseases and Department of Nutrition, Texas A&M University, College Station, TX, USA
| | - Robert Ernst
- Department of Medical Biochemistry & Molecular Biology, Medical Faculty, Saarland University, Homburg, Germany
| | - Ilya Levental
- Department of Integrative Biology & Pharmacology, University of Texas Health Science Center at Houston, Houston, TX, USA.
| |
Collapse
|
32
|
Soloviov D, Cai YQ, Bolmatov D, Suvorov A, Zhernenkov K, Zav'yalov D, Bosak A, Uchiyama H, Zhernenkov M. Functional lipid pairs as building blocks of phase-separated membranes. Proc Natl Acad Sci U S A 2020; 117:4749-4757. [PMID: 32071249 PMCID: PMC7060688 DOI: 10.1073/pnas.1919264117] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Biological membranes exhibit a great deal of compositional and phase heterogeneity due to hundreds of chemically distinct components. As a result, phase separation processes in cell membranes are extremely difficult to study, especially at the molecular level. It is currently believed that the lateral membrane heterogeneity and the formation of domains, or rafts, are driven by lipid-lipid and lipid-protein interactions. Nevertheless, the underlying mechanisms regulating membrane heterogeneity remain poorly understood. In the present work, we combine inelastic X-ray scattering with molecular dynamics simulations to provide direct evidence for the existence of strongly coupled transient lipid pairs. These lipid pairs manifest themselves experimentally through optical vibrational (a.k.a. phononic) modes observed in binary (1,2-dipalmitoyl-sn-glycero-3-phosphocholine [DPPC]-cholesterol) and ternary (DPPC-1,2-dioleoyl-sn-glycero-3-phosphocholine/1-palmitoyl-2-oleoyl-glycero-3-phosphocholine [DOPC/POPC]-cholesterol) systems. The existence of a phononic gap in these vibrational modes is a direct result of the finite size of patches formed by these lipid pairs. The observation of lipid pairs provides a spatial (subnanometer) and temporal (subnanosecond) window into the lipid-lipid interactions in complex mixtures of saturated/unsaturated lipids and cholesterol. Our findings represent a step toward understanding the lateral organization and dynamics of membrane domains using a well-validated probe with a high spatial and temporal resolution.
Collapse
Affiliation(s)
- Dmytro Soloviov
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny 141701, Russia
- Frank Laboratory for Neutron Physics, Joint Institute for Nuclear Research, Dubna 141980, Russia
- Department of Physics, Taras Shevchenko National University of Kyiv, Kyiv 01601, Ukraine
- Nuclear Facility Safety Department, Institute for Safety Problems of Nuclear Power Plants of National Academy of Science of Ukraine, Chornobyl 07270, Ukraine
| | - Yong Q Cai
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY 11973
| | - Dima Bolmatov
- Large Scale Structures Group, Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831
- Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996
| | - Alexey Suvorov
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY 11973
| | - Kirill Zhernenkov
- Jülich Centre for Neutron Science at Heinz Maier-Leibnitz Zentrum, Forschungszentrum Jülich GmbH, 85748 Garching, Germany
- Frank Laboratory for Neutron Physics, Joint Institute for Nuclear Research, Dubna 141980, Russia
| | - Dmitry Zav'yalov
- Department of Physics, Volgograd State Technical University, Volgograd 400005, Russia
| | - Alexey Bosak
- Experiments Division, European Synchrotron Radiation Facility, 38043 Grenoble, France
| | - Hiroshi Uchiyama
- Japan Synchrotron Radiation Research Institute, SPring-8, Sayo, Hyogo 679-5198, Japan
| | - Mikhail Zhernenkov
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY 11973;
| |
Collapse
|
33
|
Levental I, Levental KR, Heberle FA. Lipid Rafts: Controversies Resolved, Mysteries Remain. Trends Cell Biol 2020; 30:341-353. [PMID: 32302547 DOI: 10.1016/j.tcb.2020.01.009] [Citation(s) in RCA: 316] [Impact Index Per Article: 79.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 01/23/2020] [Accepted: 01/24/2020] [Indexed: 01/08/2023]
Abstract
The lipid raft hypothesis postulates that lipid-lipid interactions can laterally organize biological membranes into domains of distinct structures, compositions, and functions. This proposal has in equal measure exhilarated and frustrated membrane research for decades. While the physicochemical principles underlying lipid-driven domains has been explored and is well understood, the existence and relevance of such domains in cells remains elusive, despite decades of research. Here, we review the conceptual underpinnings of the raft hypothesis and critically discuss the supporting and contradicting evidence in cells, focusing on why controversies about the composition, properties, and even the very existence of lipid rafts remain unresolved. Finally, we highlight several recent breakthroughs that may resolve existing controversies and suggest general approaches for moving beyond questions of the existence of rafts and towards understanding their physiological significance.
Collapse
Affiliation(s)
- Ilya Levental
- Department of Integrative Biology and Pharmacology, McGovern Medical School, University of Texas Health Science Center, Houston, TX 70030, USA.
| | - Kandice R Levental
- Department of Integrative Biology and Pharmacology, McGovern Medical School, University of Texas Health Science Center, Houston, TX 70030, USA
| | - Frederick A Heberle
- Department of Chemistry, University of Tennessee, Knoxville, TN 37996, USA; Shull Wollan Center, Oak Ridge National Laboratory, Oak Ridge, TN 33830, USA
| |
Collapse
|
34
|
Zhu K, Su H. Unraveling Dynamic Transitions in Time-Resolved Biomolecular Motions by A Dressed Diffusion Model. J Phys Chem A 2020; 124:613-617. [PMID: 31589443 DOI: 10.1021/acs.jpca.9b08142] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Recent experimental data reveal the complexity of diffusion dynamics beyond the scope of classical Brownian dynamics. The particles exhibit diverse diffusive motions from the anomalous toward classical diffusion over a wide range of temporal scales. Here a dressed diffusion model is developed to account for non-Brownian phenomena. By coupling the particle dynamics with a local field, the dressed diffusion model generalizes the Langevin equation through coupled damping kernels and generates the salient feature of time-dependent diffusion dynamics reported in the experimental measurements of biomolecules. The dressed diffusion model provides one quantitative aspect for future endeavors in this rapid-growing field.
Collapse
Affiliation(s)
- Kaicheng Zhu
- Department of Chemistry , The Hong Kong University of Science and Technology , Clear Water Bay, Kowloon , Hong Kong
| | - Haibin Su
- Department of Chemistry , The Hong Kong University of Science and Technology , Clear Water Bay, Kowloon , Hong Kong
| |
Collapse
|
35
|
Gu RX, Baoukina S, Tieleman DP. Phase Separation in Atomistic Simulations of Model Membranes. J Am Chem Soc 2020; 142:2844-2856. [DOI: 10.1021/jacs.9b11057] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Ruo-Xu Gu
- Centre for Molecular Simulation and Department of Biological Sciences, University of Calgary, 2500 University Drive, N.W., Calgary, Alberta T2N 1N4, Canada
| | - Svetlana Baoukina
- Centre for Molecular Simulation and Department of Biological Sciences, University of Calgary, 2500 University Drive, N.W., Calgary, Alberta T2N 1N4, Canada
| | - D. Peter Tieleman
- Centre for Molecular Simulation and Department of Biological Sciences, University of Calgary, 2500 University Drive, N.W., Calgary, Alberta T2N 1N4, Canada
| |
Collapse
|
36
|
Allender DW, Giang H, Schick M. Model Plasma Membrane Exhibits a Microemulsion in Both Leaves Providing a Foundation for "Rafts". Biophys J 2020; 118:1019-1031. [PMID: 32023433 DOI: 10.1016/j.bpj.2020.01.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 12/02/2019] [Accepted: 01/03/2020] [Indexed: 12/22/2022] Open
Abstract
We consider a model lipid plasma membrane, one that describes the outer leaf as consisting of sphingomyelin, phosphatidylcholine, and cholesterol and the inner leaf of phosphatidylethanolamine, phosphatidylserine, phosphatidylcholine, and cholesterol. Their relative compositions are taken from experiment; the cholesterol freely interchanges between leaves. Fluctuations in local composition are coupled to fluctuations in the local membrane curvature, as in the Leibler-Andelman mechanism. Structure factors of components in both leaves display a peak at nonzero wavevector. This indicates that the disordered fluid membrane is characterized by structure of the corresponding wavelength. The scale is given by membrane properties: its bending modulus and its surface tension, which arises from the membrane's connections to the cytoskeleton. From measurements on the plasma membrane, this scale is on the order of 100 nm. We find that the membrane can be divided into two different kinds of domains that differ not only in their composition but also in their curvature. The first domain in the outer, exoplasmic leaf is rich in cholesterol and sphingomyelin, whereas the inner, cytoplasmic leaf is rich in phosphatidylserine and phosphatidylcholine. The second kind of domain is rich in phosphatidylcholine in the outer leaf and in cholesterol and phosphatidylethanolamine in the inner leaf. The theory provides a tenable basis for the origin of structure in the plasma membrane and an illuminating picture of the organization of lipids therein.
Collapse
Affiliation(s)
- David W Allender
- Department of Physics, University of Washington, Seattle, Washington; Department of Physics, Kent State University, Kent, Ohio
| | - Ha Giang
- Department of Physics, University of Washington, Seattle, Washington; Viettel Aerospace Institute, Hanoi, Vietnam
| | - M Schick
- Department of Physics, University of Washington, Seattle, Washington.
| |
Collapse
|
37
|
P. Sugár I. A generalization of the Shell Theorem.Electric potential of charged spheres and charged vesicles surrounded by electrolyte. AIMS BIOPHYSICS 2020. [DOI: 10.3934/biophy.2020007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
|
38
|
Enoki TA, Feigenson GW. Asymmetric Bilayers by Hemifusion: Method and Leaflet Behaviors. Biophys J 2019; 117:1037-1050. [PMID: 31493862 DOI: 10.1016/j.bpj.2019.07.054] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Revised: 06/13/2019] [Accepted: 07/08/2019] [Indexed: 01/03/2023] Open
Abstract
We describe a new method to prepare asymmetric giant unilamellar vesicles (aGUVs) via hemifusion. Hemifusion of giant unilamellar vesicles and a supported lipid bilayer, triggered by calcium, promotes the lipid exchange of the fused outer leaflets mediated by lipid diffusion. We used different fluorescent dyes to monitor the inner and the outer leaflets of the unsupported aGUVs. We confirmed that almost all newly exchanged lipids in the aGUVs are found in the outer leaflet of these asymmetric vesicles. In addition, we test the stability of the aGUVs formed by hemifusion in preserving their contents during the procedure. For aGUVs prepared from the hemifusion of giant unilamellar vesicles composed of 1,2-distearoyl-sn-glycero-3-phosphocholine/1,2-dioleoyl-sn-glycero-3-phosphocholine/cholesterol = 0.39/0.39/0.22 and a supported lipid bilayer of 1,2-dioleoyl-sn-glycero-3-phosphocholine/cholesterol = 0.8/0.2, we observed the exchanged lipids to alter the bilayer properties. To access the physical and chemical properties of the asymmetric bilayer, we monitored the dye partition coefficients of individual leaflets and the generalized polarization of the fluorescence probe 6-dodecanoyl-2-[ N-methyl-N-(carboxymethyl)amino] naphthalene, a sensor for the lipid packing/order of its surroundings. For a high percentage of lipid exchange (>70%), the dye partition indicates induced-disordered and induced-ordered domains. The induced domains have distinct lipid packing/order compared to the symmetric liquid-disordered and liquid-ordered domains.
Collapse
Affiliation(s)
- Thais A Enoki
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York.
| | - Gerald W Feigenson
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York
| |
Collapse
|
39
|
The Contribution of Differential Scanning Calorimetry for the Study of Peptide/Lipid Interactions. Methods Mol Biol 2019; 1964:3-15. [PMID: 30929231 DOI: 10.1007/978-1-4939-9179-2_1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
Membrane-active peptides include a variety of molecules such as antimicrobial (AMP), cell-penetrating (CPP), viral, and amyloid peptides that are implicated in several pathologies. They constitute important targets because they are either at the basis of novel therapies (drug delivery for CPPs or antimicrobial activity for AMPs) or they are the agents causing these pathologies (viral and amyloid peptides). They all share the common property of interacting with the cellular lipid membrane in their mode of action. Therefore, a better understanding of the peptide/lipid (P/L) interaction is essential to help decipher their mechanism of action. Among the different biophysical methods that can be used to fully characterize P/L interactions, differential scanning calorimetry (DSC) allows determining the peptide effect on the lipid phase transitions, a property that reflects the P/L interaction mode. A general protocol for classical DSC experiments for P/L studies will be provided.
Collapse
|
40
|
Role of Transmembrane Proteins for Phase Separation and Domain Registration in Asymmetric Lipid Bilayers. Biomolecules 2019; 9:biom9080303. [PMID: 31349669 PMCID: PMC6723173 DOI: 10.3390/biom9080303] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 07/19/2019] [Accepted: 07/22/2019] [Indexed: 02/05/2023] Open
Abstract
It is well known that the formation and spatial correlation of lipid domains in the two apposed leaflets of a bilayer are influenced by weak lipid–lipid interactions across the bilayer’s midplane. Transmembrane proteins span through both leaflets and thus offer an alternative domain coupling mechanism. Using a mean-field approximation of a simple bilayer-type lattice model, with two two-dimensional lattices stacked one on top of the other, we explore the role of this “structural” inter-leaflet coupling for the ability of a lipid membrane to phase separate and form spatially correlated domains. We present calculated phase diagrams for various effective lipid–lipid and lipid–protein interaction strengths in membranes that contain a binary lipid mixture in each leaflet plus a small amount of added transmembrane proteins. The influence of the transmembrane nature of the proteins is assessed by a comparison with “peripheral” proteins, which result from the separation of one single integral protein into two independent units that are no longer structurally connected across the bilayer. We demonstrate that the ability of membrane-spanning proteins to facilitate domain formation requires sufficiently strong lipid–protein interactions. Weak lipid–protein interactions generally tend to inhibit phase separation in a similar manner for transmembrane as for peripheral proteins.
Collapse
|
41
|
Allender DW, Sodt AJ, Schick M. Cholesterol-Dependent Bending Energy Is Important in Cholesterol Distribution of the Plasma Membrane. Biophys J 2019; 116:2356-2366. [PMID: 31023537 PMCID: PMC6589153 DOI: 10.1016/j.bpj.2019.03.028] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Revised: 02/19/2019] [Accepted: 03/21/2019] [Indexed: 11/16/2022] Open
Abstract
We consider the plasma membrane that contains a cholesterol molar fraction of 0.4 and ask how that cholesterol is distributed between the two leaves. Because of the rapid flip-flop of cholesterol between leaves, we assume that its distribution is determined by the equality of its chemical potentials in the two leaves. When we consider only the contributions of entropy and interactions to the cholesterol chemical potential in our model system, we find, not surprisingly, that the cholesterol is mostly in the outer leaf because of the strong attraction between cholesterol and sphingomyelin (SM), which is predominantly in that leaf. We find 72% there. We then include the contribution from the bending energy in each leaf that must be overcome to join the leaves in a flat bilayer. The product of bending modulus and spontaneous curvature is obtained from simulation. We find that the addition of cholesterol to the outer leaf reduces the spontaneous curvature, which is initially positive, until it passes through zero when the molar fraction of cholesterol in the outer leaf is 0.28. Additional cholesterol is driven toward the inner leaf by the sphingomyelin phosphatidylcholine mixture. This is resisted by the bending energy contribution to the inner leaf. We find, again by simulation, that the addition of cholesterol monotonically increases the magnitude of the spontaneous curvature of the inner leaf, which is negative. This increases its bending energy. We conclude that, as a result of these competing effects, the percentage of cholesterol in the outer leaf is reduced to ∼63 ± 6%.
Collapse
Affiliation(s)
- D W Allender
- Department of Physics, University of Washington, Seattle, Washington; Department of Physics, Kent State University, Kent, Ohio
| | - A J Sodt
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Rockville, Maryland
| | - M Schick
- Department of Physics, University of Washington, Seattle, Washington.
| |
Collapse
|
42
|
Mantil E, Crippin T, Avis TJ. Domain redistribution within ergosterol-containing model membranes in the presence of the antimicrobial compound fengycin. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2019; 1861:738-747. [DOI: 10.1016/j.bbamem.2019.01.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2018] [Revised: 12/01/2018] [Accepted: 01/08/2019] [Indexed: 01/25/2023]
|
43
|
Kristanc L, Božič B, Jokhadar ŠZ, Dolenc MS, Gomišček G. The pore-forming action of polyenes: From model membranes to living organisms. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2019; 1861:418-430. [DOI: 10.1016/j.bbamem.2018.11.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 11/04/2018] [Accepted: 11/14/2018] [Indexed: 01/05/2023]
|
44
|
Almeida PF. How to Determine Lipid Interactions in Membranes from Experiment Through the Ising Model. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:21-40. [PMID: 30589556 DOI: 10.1021/acs.langmuir.8b03054] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The determination and the meaning of interactions in lipid bilayers are discussed and interpreted through the Ising model. Originally developed to understand phase transitions in ferromagnetic systems, the Ising model applies equally well to lipid bilayers. In the case of a membrane, the essence of the Ising model is that each lipid is represented by a site on a lattice and that the interaction of each site with its nearest neighbors is represented by an energy parameter ω. To calculate the thermodynamic properties of the system, such as the enthalpy, the Gibbs energy, and the heat capacity, the partition function is derived. The calculation of the configurational entropy factor in the partition function, however, requires approximations or the use of Monte Carlo (MC) simulations. Those approximations are described. Ultimately, MC simulations are used in combination with experiment to determine the interaction parameters ω in lipid bilayers. Several experimental approaches are described, which can be used to obtain interaction parameters. They include nearest-neighbor recognition, differential scanning calorimetry, and Förster resonance energy transfer. Those approaches are most powerful when used in combination of MC simulations of Ising models. Lipid membranes of different compositions are discussed, which have been studied with these approaches. They include mixtures of cholesterol, saturated (ordered) phospholipids, and unsaturated (disordered) phospholipids. The interactions between those lipid species are examined as a function of molecular properties such as the degree of unsaturation and the acyl chain length. The general rule that emerges is that interactions between different lipids are usually unfavorable. The exception is that cholesterol interacts favorably with saturated (ordered) phospholipids. However, the interaction of cholesterol with unsaturated phospholipids becomes extremely unfavorable as the degree of unsaturation increases.
Collapse
Affiliation(s)
- Paulo F Almeida
- Department of Chemistry and Biochemistry , University of North Carolina Wilmington , Wilmington , North Carolina 28403 , United States
| |
Collapse
|
45
|
Britt HM, Mosely JA, Sanderson JM. The influence of cholesterol on melittin lipidation in neutral membranes. Phys Chem Chem Phys 2019; 21:631-640. [DOI: 10.1039/c8cp06661b] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Cholesterol inclusion in membranes influences the rate and selectivity of acyl transfer from lipids to a membrane-embedded peptide.
Collapse
|
46
|
Luo Y, Maibaum L. Phase diagrams of multicomponent lipid vesicles: Effects of finite size and spherical geometry. J Chem Phys 2018; 149:174901. [DOI: 10.1063/1.5045499] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Affiliation(s)
- Yongtian Luo
- Department of Chemistry, University of Washington, Seattle, Washington 98195, USA
| | - Lutz Maibaum
- Department of Chemistry, University of Washington, Seattle, Washington 98195, USA
| |
Collapse
|
47
|
Yasuda T, Slotte JP, Murata M. Nanosized Phase Segregation of Sphingomyelin and Dihydrosphigomyelin in Unsaturated Phosphatidylcholine Binary Membranes without Cholesterol. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:13426-13437. [PMID: 30350701 DOI: 10.1021/acs.langmuir.8b02637] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
In this study, we applied fluorescence spectroscopy, differential scanning calorimetry (DSC), and 2H NMR to elucidate the properties of nanoscopic segregated domains in stearoylsphingomyelin (SSM)/dioleoylphosphatidylcholine (DOPC) and dihydrostearoylsphingomyelin (dhSSM)/DOPC binary membranes. The results obtained from fluorescence measurements suggest the existence of gel-like domains with high fluidity in both SSM and dhSSM macroscopic gel phases. The DSC thermograms showed that DOPC destabilizes SM-rich gel-like domains to a much lesser extent compared to the same amount of cholesterol. It was also found that a stable lateral segregation occurs without cholesterol, indicating that SSM itself undergoes homophilic interactions to form small gel-like domains. 2H NMR experiments disclosed differences in the temperature-dependent ordering of SSM/DOPC and dhSSM/DOPC bilayers; the dhSSM membrane showed less miscibility with the DOPC fluid phase, higher thermal stability, and tighter packing. In addition, the NMR results suggest the formation of mid-sized gel-like aggregates consisting of dhSSM. These differences could be accounted for by homophilic interactions, as previously reported ( Yasuda Biophys. J. 2016 , 110 , 431 - 440 ). In the absence of cholesterol, the moderately strong sphingomyelin (SM)/SM affinity results in the formation of small gel-like domains, whereas a stronger dhSSM/dhSSM affinity leads to larger gel-like domains. Considering the similar physicochemical features of SSM and dhSSM, the present results suggest that the formation of nanosized domains of SM is better characterized by homophilic interactions than by SM-cholesterol interplay. These effects are considered important to the ordered domain formation of SMs in biological membranes.
Collapse
Affiliation(s)
- Tomokazu Yasuda
- Department of Chemistry, Graduate School of Science , Osaka University , Toyonaka , Osaka 560-0043 , Japan
- Biochemistry, Faculty of Science and Engineering , Åbo Akademi University , Tykistökatu 6A , Turku FIN-20520 , Finland
| | - J Peter Slotte
- Biochemistry, Faculty of Science and Engineering , Åbo Akademi University , Tykistökatu 6A , Turku FIN-20520 , Finland
| | - Michio Murata
- Department of Chemistry, Graduate School of Science , Osaka University , Toyonaka , Osaka 560-0043 , Japan
| |
Collapse
|
48
|
Yagi T, Sato H. A simple model of planar membrane: An integral equation investigation. J Comput Chem 2018; 39:2576-2581. [PMID: 30394542 DOI: 10.1002/jcc.25638] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 09/03/2018] [Accepted: 09/17/2018] [Indexed: 11/08/2022]
Abstract
A simple model of a lipid membrane, a binary mixture of saturated lipids and unsaturated lipids, was studied using an integral equation theory. The planar membrane is modeled as mixture of linear and bent molecules in two-dimensional space, and site-site radial distribution function, Kirkwood-Buff (KB) integral and related quantities were computed over the whole range of the molar fraction to understand their mixing behavior. We found that a close packing of linear molecules is enhanced as the fraction of bent molecules increases, but a long range correlation between the linear molecules is weakened. A high concentration of linear molecules promotes the demixing of linear molecules and bent molecules, and enhances the long range correlation between molecules. This implies that, the higher the concentration of linear molecules, the larger clusters tend to be formed. © 2018 Wiley Periodicals, Inc.
Collapse
Affiliation(s)
- Tomoaki Yagi
- Department of Molecular Engineering, Kyoto University, Kyoto, 615-8510, Japan
| | - Hirofumi Sato
- Department of Molecular Engineering, Kyoto University, Kyoto, 615-8510, Japan
| |
Collapse
|
49
|
Wang C, Almeida PF, Regen SL. Net Interactions That Push Cholesterol Away from Unsaturated Phospholipids Are Driven by Enthalpy. Biochemistry 2018; 57:6637-6643. [DOI: 10.1021/acs.biochem.8b00983] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Chang Wang
- Department of Chemistry, Lehigh University, Bethlehem, Pennsylvania 18015, United States
| | - Paulo F. Almeida
- Department of Chemistry and Biochemistry, University of North Carolina Wilmington, Wilmington, North Carolina 28403, United States
| | - Steven L. Regen
- Department of Chemistry, Lehigh University, Bethlehem, Pennsylvania 18015, United States
| |
Collapse
|
50
|
Almeida PF, Carter FE, Kilgour KM, Raymonda MH, Tejada E. Heat Capacity of DPPC/Cholesterol Mixtures: Comparison of Single Bilayers with Multibilayers and Simulations. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:9798-9809. [PMID: 30088940 DOI: 10.1021/acs.langmuir.8b01774] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The excess heat capacity (Δ C p) of mixtures of dipalmitoylphosphatidylcholine (DPPC) and cholesterol (Chol) is examined in detail in large unilamellar vesicles (LUVs), both experimentally, using differential scanning calorimetry (DSC), and theoretically, using a three-state Ising model. The model postulates that DPPC can access three conformational states: gel, liquid-disordered (Ld), and liquid-ordered (Lo). The Lo state, however, is only available if coupled with interaction with an adjacent Chol. Δ C p was calculated using Monte Carlo simulations on a lattice and compared to experiment. The DSC results in LUVs are compared with literature data on multilamellar vesicles (MLVs). The enthalpy change of the complete phase transition from gel to Ld is identical in LUVs and MLVs, and the melting temperatures ( Tm) are similar. However, the DSC curves in LUVs are significantly broader, and the maxima of Δ C p are accordingly smaller. The parameters in the Ising model were chosen to match the DSC curves in LUVs and the nearest-neighbor recognition (NNR) data. The model reproduces the NNR data very well. It also reproduces the phase transition in DPPC, the freezing point depression induced by Chol, and the broad component of Δ C p in DPPC/Chol LUVs. However, there is a sharp component, between 5 and 15 mol % Chol, that the model does not reproduce. The broad component of Δ C p becomes dominant as Chol concentration increases, indicating that it involves melting of the Lo phase. Because the simulations reproduce this component, the conclusions regarding the nature of the phase transition at high Chol concentrations and the structure of the Lo phase are important: there is no true phase separation in DPPC/Chol LUVs. There are large domains of gel and Lo phase coexisting below Tm of DPPC, but above Tm the three states of DPPC are mixed with Chol, although clusters persist.
Collapse
Affiliation(s)
- Paulo F Almeida
- Department of Chemistry and Biochemistry , University of North Carolina Wilmington , Wilmington , North Carolina 28403 , United States
| | - Faith E Carter
- Department of Chemistry and Biochemistry , University of North Carolina Wilmington , Wilmington , North Carolina 28403 , United States
| | - Katie M Kilgour
- Department of Chemistry and Biochemistry , University of North Carolina Wilmington , Wilmington , North Carolina 28403 , United States
| | - Matthew H Raymonda
- Department of Chemistry and Biochemistry , University of North Carolina Wilmington , Wilmington , North Carolina 28403 , United States
| | - Emmanuel Tejada
- Department of Chemistry and Biochemistry , University of North Carolina Wilmington , Wilmington , North Carolina 28403 , United States
| |
Collapse
|