1
|
Ruiz GCM, do Carmo Morato LF, Pazin WM, Oliveira ON, Constantino CJL. In situ interaction between the hormone 17α-ethynylestradiol and the liquid-ordered phase composed of the lipid rafts sphingomyelin and cholesterol. Bioorg Chem 2024; 143:107002. [PMID: 38006790 DOI: 10.1016/j.bioorg.2023.107002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 11/21/2023] [Accepted: 11/22/2023] [Indexed: 11/27/2023]
Abstract
Hormone treatments are frequently associated with cardiovascular diseases and cancers in women. Additionally, the detrimental effects of their presence as contaminants in water remain a concern. The transport of hormones through cell membranes is essential for their biological action, but investigating cell permeability is challenging owing to the experimental difficulty in dealing with whole cells. In this paper, we study the interaction of the synthetic hormone 17α-ethynylestradiol (EE2) with membrane models containing the key raft components sphingomyelin (SM) and cholesterol (Chol). The models consisted of Langmuir monolayers and giant unilamellar vesicles (GUVs) that represent bilayers. EE2 induced expansion of SM monolayers upon interacting with the non-hydrated amide group of SM head, but it had practically no effect on SM GUVs because these group are not available for interaction in bilayers. In contrast, EE2 interacted with hydrated phosphate group (PO2-) and amide group of SM/Chol mixture monolayer, which could explain the loss in phase contrast of liquid-ordered GUVs suggesting pore formation. A comparison with reported EE2 effects on GUVs in the fluid phase, for which no loss in phase contrast was observed, indicates that the liquid-ordered phase consisting of lipid rafts is relevant to be associated with the changes on cell permeability caused by the hormones.
Collapse
Affiliation(s)
- Gilia Cristine Marques Ruiz
- Department of Physics, School of Technology and Applied Sciences, São Paulo State University (UNESP), Presidente Prudente, SP, Brazil.
| | - Luis Fernando do Carmo Morato
- Department of Physics, School of Technology and Applied Sciences, São Paulo State University (UNESP), Presidente Prudente, SP, Brazil
| | | | - Osvaldo N Oliveira
- Sao Carlos Institute of Physics, University of Sao Paulo (USP), Sao Carlos, SP, Brazil
| | - Carlos José Leopoldo Constantino
- Department of Physics, School of Technology and Applied Sciences, São Paulo State University (UNESP), Presidente Prudente, SP, Brazil
| |
Collapse
|
2
|
Ozolina N, Kapustina I, Gurina V, Spiridonova E, Nurminsky V. The microdomains ( rafts) of plasmalemma in the protection of the plant cell under oxidative stress. Protoplasma 2023; 260:1365-1374. [PMID: 36959427 DOI: 10.1007/s00709-023-01852-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Accepted: 03/10/2023] [Indexed: 06/18/2023]
Abstract
The investigation of the lipid-protein microdomains of the plasmalemma isolated with the aid of the non-detergent technique in the zones of the sucrose density gradient after high-speed centrifugation from the tissue pieces of beet roots, which underwent oxidative stress, was conducted. The microdomains, whose lipid composition - according to the definition - allowed us to classify them as rafts, were studied. After the exposure to oxidative stress (100 mM hydrogen peroxide), the variations in the composition of membrane lipids bound up mainly with the elevations of the content of raft-forming lipids (sterols, sterol esters). Oxidative stress provoked redistribution in the composition of sterols, which led to an elevation in the content of campesterol and in the ratio of stigmasterol/sitosterol. Furthermore, the variations were registered in the content of phospholipids and phosphoglycerolipids, which are capable of stabilizing the lamellar structure of membranes. The results obtained allow one to assume that under the oxidative stress, variations in the composition of lipids in microdomains of the plasma membrane can take place. These variations may influence the functioning of the membranes, and the membranes may participate in the protection of the plant cell.
Collapse
Affiliation(s)
- Natalia Ozolina
- Siberian Institute of Plant Physiology and Biochemistry, Siberian Branch, Russian Academy of Sciences, Irkutsk, Russia
| | - Irina Kapustina
- Siberian Institute of Plant Physiology and Biochemistry, Siberian Branch, Russian Academy of Sciences, Irkutsk, Russia
| | - Veronika Gurina
- Siberian Institute of Plant Physiology and Biochemistry, Siberian Branch, Russian Academy of Sciences, Irkutsk, Russia.
| | - Ekaterina Spiridonova
- Siberian Institute of Plant Physiology and Biochemistry, Siberian Branch, Russian Academy of Sciences, Irkutsk, Russia
| | - Vadim Nurminsky
- Siberian Institute of Plant Physiology and Biochemistry, Siberian Branch, Russian Academy of Sciences, Irkutsk, Russia
| |
Collapse
|
3
|
Suzuki KGN, Komura N, Ando H. Recently developed glycosphingolipid probes and their dynamic behavior in cell plasma membranes as revealed by single-molecule imaging. Glycoconj J 2023; 40:305-314. [PMID: 37133616 DOI: 10.1007/s10719-023-10116-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/12/2023] [Indexed: 05/04/2023]
Abstract
Glycosphingolipids, including gangliosides, are representative lipid raft markers that perform a variety of physiological roles in cell membranes. However, studies aimed at revealing their dynamic behavior in living cells are rare, mostly due to a lack of suitable fluorescent probes. Recently, the ganglio-series, lacto-series, and globo-series glycosphingolipid probes, which mimic the behavior of the parental molecules in terms of partitioning to the raft fraction, were developed by conjugating hydrophilic dyes to the terminal glycans of glycosphingolipids using state-of-art entirely chemical-based synthetic techniques. High-speed, single-molecule observation of these fluorescent probes revealed that gangliosides were scarcely trapped in small domains (100 nm in diameter) for more than 5 ms in steady-state cells, suggesting that rafts including gangliosides were always moving and very small. Furthermore, dual-color, single-molecule observations clearly showed that homodimers and clusters of GPI-anchored proteins were stabilized by transiently recruiting sphingolipids, including gangliosides, to form homodimer rafts and the cluster rafts, respectively. In this review, we briefly summarize recent studies, the development of a variety of glycosphingolipid probes as well as the identification of the raft structures including gangliosides in living cells by single-molecule imaging.
Collapse
Affiliation(s)
- Kenichi G N Suzuki
- Institute for Glyco-core Research (iGCORE), Gifu University, 501-1193, Gifu, Japan.
| | - Naoko Komura
- Institute for Glyco-core Research (iGCORE), Gifu University, 501-1193, Gifu, Japan.
| | - Hiromune Ando
- Institute for Glyco-core Research (iGCORE), Gifu University, 501-1193, Gifu, Japan.
| |
Collapse
|
4
|
Abstract
The formation of membrane vesicles is a common feature in all eukaryotes. Lipid rafts are the best-studied example of membrane domains for both eukaryotes and prokaryotes, and their existence also is suggested in Archaea membranes. Lipid rafts are involved in the formation of transport vesicles, endocytic vesicles, exocytic vesicles, synaptic vesicles and extracellular vesicles, as well as enveloped viruses. Two mechanisms of how rafts are involved in vesicle formation have been proposed: first, that raft proteins and/or lipids located in lipid rafts associate with coat proteins that form a budding vesicle, and second, vesicle budding is triggered by enzymatic generation of cone-shaped ceramides and inverted cone-shaped lyso-phospholipids. In both cases, induction of curvature is also facilitated by the relaxation of tension in the raft domain. In this Review, we discuss the role of raft-derived vesicles in several intracellular trafficking pathways. We also highlight their role in different pathways of endocytosis, and in the formation of intraluminal vesicles (ILVs) through budding inwards from the multivesicular body (MVB) membrane, because rafts inside MVB membranes are likely to be involved in loading RNA into ILVs. Finally, we discuss the association of glycoproteins with rafts via the glycocalyx.
Collapse
Affiliation(s)
- Karolina Sapoń
- Institute of Biology, University of Opole, Kominka 6, 45-032 Opole, Poland
| | - Rafał Mańka
- Institute of Biology, University of Opole, Kominka 6, 45-032 Opole, Poland
| | - Teresa Janas
- Institute of Biology, University of Opole, Kominka 6, 45-032 Opole, Poland
| | - Tadeusz Janas
- Institute of Biology, University of Opole, Kominka 6, 45-032 Opole, Poland
| |
Collapse
|
5
|
Heimburg T. The excitable fluid mosaic. Biochim Biophys Acta Biomembr 2023; 1865:184104. [PMID: 36642342 DOI: 10.1016/j.bbamem.2022.184104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 11/23/2022] [Accepted: 12/13/2022] [Indexed: 01/15/2023]
Abstract
The Fluid Mosaic Model by Singer & Nicolson proposes that biological membranes consist of a fluid lipid layer into which integral proteins are embedded. The lipid membrane acts as a two-dimensional liquid in which the proteins can diffuse and interact. Until today, this view seems very reasonable and is the predominant picture in the literature. However, there exist broad melting transitions in biomembranes some 10-20 degrees below physiological temperatures that reach up to body temperature. Since they are found below body temperature, Singer & Nicolson did not pay any further attention to the melting process. But this is a valid view only as long as nothing happens. The transition temperature can be influenced by membrane tension, pH, ionic strength and other variables. Therefore, it is not generally correct that the physiological temperature is above this transition. The control over the membrane state by changing the intensive variables renders the membrane as a whole excitable. One expects phase behavior and domain formation that leads to protein sorting and changes in membrane function. Thus, the lipids become an active ingredient of the biological membrane. The melting transition affects the elastic constants of the membrane. This allows for the generation of propagating pulses in nerves and the formation of ion-channel-like pores in the lipid membranes. Here we show that on top of the fluid mosaic concept there exists a wealth of excitable phenomena that go beyond the original picture of Singer & Nicolson.1.
Collapse
Affiliation(s)
- Thomas Heimburg
- Membrane Biophysics Group, Niels Bohr Institute, University of Copenhagen, Denmark.
| |
Collapse
|
6
|
Abstract
Biomembrane order, dynamics, and other essential physicochemical parameters are controlled by cholesterol, a major component of mammalian cell membranes. Although cholesterol is well known to exhibit a condensing effect on fluid lipid membranes, the extent of stiffening that occurs with different degrees of lipid acyl chain unsaturation remains an enigma. In this review, we show that cholesterol locally increases the bending rigidity of both unsaturated and saturated lipid membranes, suggesting there may be a length-scale dependence of the bending modulus. We review our published data that address the origin of the mechanical effects of cholesterol on unsaturated and polyunsaturated lipid membranes and their role in biomembrane functions. Through a combination of solid-state deuterium NMR spectroscopy and neutron spin-echo spectroscopy, we show that changes in molecular packing cause the universal effects of cholesterol on the membrane bending rigidity. Our findings have broad implications for the role of cholesterol in lipid–protein interactions as well as raft-like mixtures, drug delivery applications, and the effects of antimicrobial peptides on lipid membranes.
Collapse
Affiliation(s)
- Fathima T Doole
- Deaprtment of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, 85712, USA
| | - Teshani Kumarage
- Department of Physics, Virginia Tech, Blacksburg, VA, 24061, USA.,Center for Soft Matter and Biological Physics, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Rana Ashkar
- Department of Physics, Virginia Tech, Blacksburg, VA, 24061, USA. .,Center for Soft Matter and Biological Physics, Virginia Tech, Blacksburg, VA, 24061, USA.
| | - Michael F Brown
- Deaprtment of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, 85712, USA. .,Department of Physics, University of Arizona, Tucson, AZ, 85712, USA.
| |
Collapse
|
7
|
Ozolina NV, Kapustina IS, Gurina VV, Nurminsky VN. Role of tonoplast microdomains in plant cell protection against osmotic stress. Planta 2022; 255:65. [PMID: 35150330 DOI: 10.1007/s00425-021-03800-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 11/22/2021] [Indexed: 06/14/2023]
Abstract
Variations in the content of tonoplast microdomains, isolated with the aid of a non-detergent technique, are induced by osmotic stress and may take part in plant cell adaptive mechanisms. Investigation of tonoplast microdomain lipids isolated with the aid of the non-detergent technique from beetroots (Beta vulgaris L.) subjected to either hyperosmotic or hypoosmotic stress was conducted. Earlier, an important role of tonoplast lipids in the protection of plant cells from stress was demonstrated (Ozolina et al. 2020a). In the present paper, we have put forward a hypothesis that lipids of microdomains of raft nature present in the tonoplast are responsible for this protective function. The variations in the content of lipids of the studied nondetergent-isolated microdomains (NIMs) under hyperosmotic and hypoosmotic stresses were different. Under hyperosmotic stress, in the scrutinized microdomains, some variations in the content of lipids were registered, which were characteristic of the already known protective anti-stress mechanisms. These variations were represented by an increase in sterols and polar lipids capable of stabilizing the bilayer structure of the membranes. The found variations in the content of sterols may be bound up with some intensification of the autophagy process under stress because sterols foster the formation of new membrane contacts necessary for this process. Under hypoosmotic stress, the pattern of redistribution of the lipids in the scrutinized membrane structures was different: the largest part of the lipids appeared to be represented by hydrocarbons, which fulfilled mainly a protective function in plants and could prevent the excess water influx into the vacuole. The results obtained not only demonstrate the possible functions of the vacuolar membrane microdomains but also put forward an assumption on the role of any membrane microdomain in the protection mechanisms of the plant cell.
Collapse
Affiliation(s)
- Natalia V Ozolina
- Siberian Institute of Plant Physiology and Biochemistry, Siberian Branch, Russian Academy of Sciences, 132, Lermontov St., Irkutsk, 664033, Russia
| | - Irina S Kapustina
- Siberian Institute of Plant Physiology and Biochemistry, Siberian Branch, Russian Academy of Sciences, 132, Lermontov St., Irkutsk, 664033, Russia
| | - Veronika V Gurina
- Siberian Institute of Plant Physiology and Biochemistry, Siberian Branch, Russian Academy of Sciences, 132, Lermontov St., Irkutsk, 664033, Russia
| | - Vadim N Nurminsky
- Siberian Institute of Plant Physiology and Biochemistry, Siberian Branch, Russian Academy of Sciences, 132, Lermontov St., Irkutsk, 664033, Russia.
| |
Collapse
|
8
|
Abstract
We review the current theories of nanodomain, or "raft," formation. We emphasize that the idea that they are co-exisiting Lo and Ld phases is fraught with difficulties, as is the closely related idea that they are due to critical fluctuations. We then review an alternate theory that the plasma membrane is a two-dimensional microemulsion, and that the mechanism that drives to zero the line tension between Lo and Ld phases is the coupling of height and composition fluctuations. The theory yields rafts of SM and cholesterol in the outer leaf and POPS and POPC in the inner leaf. The "sea" between rafts consists of POPC in the outer leaf and POPE and cholesterol in the inner leaf. The characteristic size of the domain structures is tens of nanometers.
Collapse
Affiliation(s)
- D W Allender
- Department of Physics, University of Washington, Seattle, Washington, USA.,Department of Physics, Kent State University, Kent, OH, USA
| | - M Schick
- Department of Physics, University of Washington, Seattle, Washington, USA.
| |
Collapse
|
9
|
Ozolina NV, Kapustina IS, Gurina VV, Bobkova VA, Nurminsky VN. Role of Plasmalemma Microdomains ( Rafts) in Protection of the Plant Cell Under Osmotic Stress. J Membr Biol 2021; 254:429-439. [PMID: 34302495 DOI: 10.1007/s00232-021-00194-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 07/08/2021] [Indexed: 12/17/2022]
Abstract
Lipid-protein microdomains (presumably rafts) of the plasmalemma isolated from the beetroots subjected to hyperosmotic stress and hypoosmotic stress were studied. In these microdomains, the variations in the composition of total lipids, sterols, and fatty acids were observed. These variations differed under hypo- and hyperosmotic types of stress. We presumed that such variations were bound up with different strategies, which are probably related to protecting the cell from osmotic stress. One of the protection tendencies might be related, in our opinion, to credible growth of the content of such lipids as sterols and sterol esters, which are considered as raft-forming. Under osmotic stress, these lipids can contribute to the formation of both new raft structures and new membrane contacts of plasmalemma with intracellular organelles. Another protection tendency may be bound up with the redistribution of membrane phospholipids and phosphoglycerolipids possibly to stabilize the membrane's lamellar structure, which is ensured by credible growth of the content of such lipids as phosphatidylcholines, phosphatidylinositols, and digalactosyldiacylglycerol. The participation of lipid-protein microdomains in the adaptive mechanisms of plant cells may, in our opinion, also be bound up with the redistribution of membrane sterols, which (redistribution) in a number of variants may provoke credible growth in the content of cholesterol or "anti-stress" sterols (campesterol and stigmasterol). So, according to our results, the variations in the content of the plasmalemma lipid-protein microdomains take place under osmotic stress. These variations may influence the functioning of plasmalemma and take part in the adaptive mechanisms of plant cells.
Collapse
Affiliation(s)
- N V Ozolina
- Siberian Institute of Plant Physiology and Biochemistry, Siberian Branch, Russian Academy of Sciences,, 132, Lermontov St, Irkutsk, Russia
| | - I S Kapustina
- Siberian Institute of Plant Physiology and Biochemistry, Siberian Branch, Russian Academy of Sciences,, 132, Lermontov St, Irkutsk, Russia
| | - V V Gurina
- Siberian Institute of Plant Physiology and Biochemistry, Siberian Branch, Russian Academy of Sciences,, 132, Lermontov St, Irkutsk, Russia.
| | - V A Bobkova
- Siberian Institute of Plant Physiology and Biochemistry, Siberian Branch, Russian Academy of Sciences,, 132, Lermontov St, Irkutsk, Russia
- Irkutsk State University, 5, Sukhe-Bator St, Irkutsk, Russia
| | - V N Nurminsky
- Siberian Institute of Plant Physiology and Biochemistry, Siberian Branch, Russian Academy of Sciences,, 132, Lermontov St, Irkutsk, Russia
| |
Collapse
|
10
|
Bernabé-Rubio M, Bosch-Fortea M, Alonso MA, Bernardino de la Serna J. Multi-dimensional and spatiotemporal correlative imaging at the plasma membrane of live cells to determine the continuum nano-to-micro scale lipid adaptation and collective motion. Methods 2021; 193:136-147. [PMID: 34126167 DOI: 10.1016/j.ymeth.2021.06.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 06/07/2021] [Accepted: 06/09/2021] [Indexed: 12/25/2022] Open
Abstract
The primary cilium is a specialized plasma membrane protrusion with important receptors for signalling pathways. In polarized epithelial cells, the primary cilium assembles after the midbody remnant (MBR) encounters the centrosome at the apical surface. The membrane surrounding the MBR, namely remnant-associated membrane patch (RAMP), once situated next to the centrosome, releases some of its lipid components to form a centrosome-associated membrane patch (CAMP) from which the ciliary membrane stems. The RAMP undergoes a spatiotemporal membrane refinement during the formation of the CAMP, which becomes highly enriched in condensed membranes with low lateral mobility. To better understand this process, we have developed a correlative imaging approach that yields quantitative information about the lipid lateral packing, its mobility and collective assembly at the plasma membrane at different spatial scales over time. Our work paves the way towards a quantitative understanding of the spatiotemporal lipid collective assembly at the plasma membrane as a functional determinant in cell biology and its direct correlation with the membrane physicochemical state. These findings allowed us to gain a deeper insight into the mechanisms behind the biogenesis of the ciliary membrane of polarized epithelial cells.
Collapse
Affiliation(s)
- Miguel Bernabé-Rubio
- Department of Cell Biology and Immunology, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, Madrid 28049, Spain; King's College London Centre for Stem Cells and Regenerative Medicine, 28th Floor, Tower Wing, Guy's Campus, Great Maze Pond, London SE1 9RT, UK
| | - Minerva Bosch-Fortea
- Department of Cell Biology and Immunology, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, Madrid 28049, Spain; Institute of Bioengineering and School of Engineering and Materials Science, Queen Mary, University of London, Mile End Road, London E1 4NS, UK
| | - Miguel A Alonso
- Department of Cell Biology and Immunology, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, Madrid 28049, Spain
| | - Jorge Bernardino de la Serna
- Central Laser Facility, Rutherford Appleton Laboratory, MRC-Research Complex at Harwell, Science and Technology Facilities Council, Harwell OX11 0QX, UK; National Heart and Lung Institute, Imperial College London, Sir Alexander Fleming Building, London SW7 2AZ, UK; NIHR Imperial Biomedical Research Centre, London SW7 2AZ, UK.
| |
Collapse
|
11
|
Janas T, Sapoń K, Janas T, Yarus M. Specific binding of VegT mRNA localization signal to membranes in Xenopus oocytes. Biochim Biophys Acta Mol Cell Res 2021; 1868:118952. [PMID: 33422615 DOI: 10.1016/j.bbamcr.2021.118952] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 07/11/2020] [Revised: 12/18/2020] [Accepted: 12/30/2020] [Indexed: 10/22/2022]
Abstract
We have studied the interaction of a VegT mRNA localization signal sequence with the membranes of the mitochondrial cloud in Xenopus oocytes, and the binding of the VegT mRNA signal sequence to the lipid raft regions of the vesicles bounded by ordered and disordered phospholipid bilayers. RNA preference for the membranes of the mitochondrial cloud was confirmed using microscopy of a fluorescence resonance energy transfer from RNA molecules to membranes. Our studies show that VegT mRNA has a higher affinity for ordered regions of lipid bilayers. This conclusion is supported by the dissociation constant measurements for RNA-liposome complex and the visualization of the FRET signal between giant vesicles and RNA. Our data indicate that these affinities are sensitive and distinct to the location of the localization elements within the VegT mRNA localization signal structure. Therefore, specific binding of VegT mRNA localization signal sequence to membranes can be responsible for polarized distribution of VegT mRNA in Xenopus oocytes. We suggest that the mechanism of this binding can involve the interaction of the localization elements within the VegT mRNA signal sequence with lipid raft regions of the mitochondrial cloud membranes, thereby utilizing localization elements as novel lipid raft-binding RNA motifs.
Collapse
Affiliation(s)
- Tadeusz Janas
- Institute of Biology, University of Opole, Kominka 6, 45-032 Opole, Poland; Department of MCD Biology, University of Colorado, Boulder, CO 80309, USA.
| | - Karolina Sapoń
- Institute of Biology, University of Opole, Kominka 6, 45-032 Opole, Poland
| | - Teresa Janas
- Institute of Biology, University of Opole, Kominka 6, 45-032 Opole, Poland
| | - Michael Yarus
- Department of MCD Biology, University of Colorado, Boulder, CO 80309, USA
| |
Collapse
|
12
|
Ozolina NV, Nesterkina IS, Gurina VV, Nurminsky VN. Non-detergent Isolation of Membrane Structures from Beet Plasmalemma and Tonoplast Having Lipid Composition Characteristic of Rafts. J Membr Biol 2020; 253:479-489. [PMID: 32954443 DOI: 10.1007/s00232-020-00137-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 08/26/2020] [Indexed: 10/23/2022]
Abstract
Vacuolar and plasma membranes were isolated by a detergent-free method from beet roots (Beta vulgaris L.), and were fractionated in a sucrose density gradient of 15-60% by high-speed centrifugation at 200,000×g during 18 h. The membrane material distributed over the sucrose density gradient was analyzed for the presence of lipids characteristic of raft structures in different zones of the gradient. The quantitative and qualitative content of lipids and sterols, and the composition of fatty acids were analyzed. Some membrane structures differing in their biochemical characteristics were revealed to be located in different zones of the sucrose gradient. The results of the analysis allowed us to identify three zones in the sucrose gradient after the vacuolar membrane fractionation and two zones in the plasma membrane where membrane structures, which may be defined as rafts for their lipid composition, were presented.
Collapse
Affiliation(s)
- Natalia V Ozolina
- Siberian Institute of Plant Physiology and Biochemistry, Siberian Branch, Russian Academy of Sciences, 132, Lermontov st., Irkutsk, 664033, Russia
| | - Irina S Nesterkina
- Siberian Institute of Plant Physiology and Biochemistry, Siberian Branch, Russian Academy of Sciences, 132, Lermontov st., Irkutsk, 664033, Russia
| | - Veronika V Gurina
- Siberian Institute of Plant Physiology and Biochemistry, Siberian Branch, Russian Academy of Sciences, 132, Lermontov st., Irkutsk, 664033, Russia
| | - Vadim N Nurminsky
- Siberian Institute of Plant Physiology and Biochemistry, Siberian Branch, Russian Academy of Sciences, 132, Lermontov st., Irkutsk, 664033, Russia.
| |
Collapse
|
13
|
Abstract
The plasma membrane (PM) spatiotemporal organization is one of the major factors controlling cell signaling and whole-cell homeostasis. The PM lipids, including cholesterol, determine the physicochemical properties of the membrane bilayer and thus play a crucial role in all membrane-dependent cellular processes. It is known that lipid content and distribution in the PM are not random, and their transversal and lateral organization is highly controlled. Mainly sphingolipid- and cholesterol-rich lipid nanodomains, historically referred to as rafts, are extremely dynamic “hot spots” of the PM controlling the function of many cell surface proteins and receptors. In the first part of this review, we will focus on the recent advances of PM investigation and the current PM concept. In the second part, we will discuss the importance of several classes of ABC transporters whose substrates are lipids for the PM organization and dynamics. Finally, we will briefly present the significance of lipid ABC transporters for immune responses.
Collapse
Affiliation(s)
- Ambroise Wu
- Faculty of Biotechnology, University of Wroclaw, Wroclaw, Poland
| | | | - Stephane Savary
- Lab. Bio-PeroxIL EA7270, University of Bourgogne Franche-Comté, Dijon, France
| | - Yannick Hamon
- Aix Marseille University, CNRS, INSERM, CIML, Centre d'Immunologie de Marseille-Luminy, Marseille, France
| | - Tomasz Trombik
- Faculty of Biotechnology, University of Wroclaw, Wroclaw, Poland
| |
Collapse
|
14
|
Petersen EN, Pavel MA, Wang H, Hansen SB. Disruption of palmitate-mediated localization; a shared pathway of force and anesthetic activation of TREK-1 channels. Biochim Biophys Acta Biomembr 2020; 1862:183091. [PMID: 31672538 PMCID: PMC6907892 DOI: 10.1016/j.bbamem.2019.183091] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Revised: 09/15/2019] [Accepted: 09/17/2019] [Indexed: 12/22/2022]
Abstract
TWIK related K+ channel (TREK-1) is a mechano- and anesthetic sensitive channel that when activated attenuates pain and causes anesthesia. Recently the enzyme phospholipase D2 (PLD2) was shown to bind to the channel and generate a local high concentration of phosphatidic acid (PA), an anionic signaling lipid that gates TREK-1. In a biological membrane, the cell harnesses lipid heterogeneity (lipid compartments) to control gating of TREK-1 using palmitate-mediated localization of PLD2. Here we discuss the ability of mechanical force and anesthetics to disrupt palmitate-mediated localization of PLD2 giving rise to TREK-1's mechano- and anesthetic-sensitive properties. The likely consequences of this indirect lipid-based mechanism of activation are discussed in terms of a putative model for excitatory and inhibitory mechano-effectors and anesthetic sensitive ion channels in a biological context. Lastly, we discuss the ability of locally generated PA to reach mM concentrations near TREK-1 and the biophysics of localized signaling. Palmitate-mediated localization of PLD2 emerges as a central control mechanism of TREK-1 responding to mechanical force and anesthetic action. This article is part of a Special Issue entitled: Molecular biophysics of membranes and membrane proteins.
Collapse
Affiliation(s)
- E Nicholas Petersen
- Department of Molecular Medicine, The Scripps Research Institute, Jupiter, FL 33458, USA; Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Mahmud Arif Pavel
- Department of Molecular Medicine, The Scripps Research Institute, Jupiter, FL 33458, USA; Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Hao Wang
- Department of Molecular Medicine, The Scripps Research Institute, Jupiter, FL 33458, USA; Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Scott B Hansen
- Department of Molecular Medicine, The Scripps Research Institute, Jupiter, FL 33458, USA; Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA.
| |
Collapse
|
15
|
Sharma N, Baek K, Shimokawa N, Takagi M. Effect of temperature on raft-dependent endocytic cluster formation during activation of Jurkat T cells by concanavalin A. J Biosci Bioeng 2018; 127:479-485. [PMID: 30355461 DOI: 10.1016/j.jbiosc.2018.09.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 09/18/2018] [Accepted: 09/21/2018] [Indexed: 01/28/2023]
Abstract
Temperature plays an important role in the immune response. Acclimatization occurs when there are changes in ambient temperature over a long period. In this study, we used the human leukemic Jurkat T cell line to study the effect of temperature on the immune system using concanavalin A (ConA), a plant-derived immunostimulant, as a trigger for T-cell activation. Previously, we have reported endocytic intracellular cluster formation during T-cell activation by ConA with the aid of rafts and polymerization of the cytoskeleton (actin and microtubules). Here, we investigated the effect of temperature on cluster formation (with the aid of three-dimensional images of the cells) and on the stability of rafts, actin, and microtubules. When the temperature was changed between 23°C and 37°C (physiological temperature), clusters could be observed throughout this temperature range. Raft structure was stabilized at lower temperatures but destabilized at higher temperatures. Actin was stable when the temperature was higher than 27°C. When actin was depolymerized, clustering was not observed at 37°C but could be observed at 23°C. There were no changes in microtubules within this temperature range. Thus, raft clustering may be associated with raft stability at lower temperatures (<27°C) and with actin at higher temperatures (≥27°C). Hence, we provided insight into the associations between temperature, rafts, actin, and microtubules in the immune response.
Collapse
Affiliation(s)
- Neha Sharma
- School of Materials Science, Japan Advanced Institute of Science and Technology (JAIST), 1-1 Asahidai, Nomi, Ishikawa 923-1292, Japan
| | - KeangOK Baek
- School of Materials Science, Japan Advanced Institute of Science and Technology (JAIST), 1-1 Asahidai, Nomi, Ishikawa 923-1292, Japan
| | - Naofumi Shimokawa
- School of Materials Science, Japan Advanced Institute of Science and Technology (JAIST), 1-1 Asahidai, Nomi, Ishikawa 923-1292, Japan
| | - Masahiro Takagi
- School of Materials Science, Japan Advanced Institute of Science and Technology (JAIST), 1-1 Asahidai, Nomi, Ishikawa 923-1292, Japan.
| |
Collapse
|
16
|
Termini L, Boccardo E. Epithelial Organotypic Cultures: A Viable Model to Address Mechanisms of Carcinogenesis by Epitheliotropic Viruses. Curr Top Med Chem 2018; 18:246-255. [PMID: 29637861 DOI: 10.2174/1568026618666180410125850] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Revised: 02/08/2018] [Accepted: 03/24/2018] [Indexed: 11/22/2022]
Abstract
In vitro culture of primary or established cell lines is one of the leading techniques in many areas of basic biological research. The use of pure or highly enriched cultures of specific cell types obtained from different tissues and genetics backgrounds has greatly contributed to our current understanding of normal and pathological cellular processes. Cells in culture are easily propagated generating an almost endless source of material for experimentation. Besides, they can be manipulated to achieve gene silencing, gene overexpression and genome editing turning possible the dissection of specific gene functions and signaling pathways. However, monolayer and suspension cultures of cells do not reproduce the cell type diversity, cell-cell contacts, cell-matrix interactions and differentiation pathways typical of the three-dimensional environment of tissues and organs from where they were originated. Therefore, different experimental animal models have been developed and applied to address these and other complex issues in vivo. However, these systems are costly and time consuming. Most importantly the use of animals in scientific research poses moral and ethical concerns facing a steadily increasing opposition from different sectors of the society. Therefore, there is an urgent need for the development of alternative in vitro experimental models that accurately reproduce the events observed in vivo to reduce the use of animals. Organotypic cultures combine the flexibility of traditional culture systems with the possibility of culturing different cell types in a 3D environment that reproduces both the structure and the physiology of the parental organ. Here we present a summarized description of the use of epithelial organotypic for the study of skin physiology, human papillomavirus biology and associated tumorigenesis.
Collapse
Affiliation(s)
- Lara Termini
- Centro de Investigacao Translacional em Oncologia (LIM24), Instituto do Cancer do Estado de 11Sao Paulo (ICESP), Sao Paulo, Brazil
| | - Enrique Boccardo
- Department of Microbiology, Institute of Biomedical Sciences, University of Sao Paulo (USP), Av. Prof. Lineu Prestes 1374, 05508-900, Sao Paulo, SP, Brazil
| |
Collapse
|
17
|
West E, Osborne C, Bate C. The cholesterol ester cycle regulates signalling complexes and synapse damage caused by amyloid-β. J Cell Sci 2017; 130:3050-3059. [PMID: 28760925 DOI: 10.1242/jcs.205484] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Accepted: 07/26/2017] [Indexed: 02/01/2023] Open
Abstract
Cholesterol is required for the formation and function of some signalling platforms. In synaptosomes, amyloid-β (Aβ) oligomers, the causative agent in Alzheimer's disease, bind to cellular prion proteins (PrPC) resulting in increased cholesterol concentrations, translocation of cytoplasmic phospholipase A2 (cPLA2, also known as PLA2G4A) to lipid rafts, and activation of cPLA2 The formation of Aβ-PrPC complexes is controlled by the cholesterol ester cycle. In this study, Aβ activated cholesterol ester hydrolases, which released cholesterol from stores of cholesterol esters and stabilised Aβ-PrPC complexes, resulting in activated cPLA2 Conversely, cholesterol esterification reduced cholesterol concentrations causing the dispersal of Aβ-PrPC complexes. In cultured neurons, the cholesterol ester cycle regulated Aβ-induced synapse damage; cholesterol ester hydrolase inhibitors protected neurons, while inhibition of cholesterol esterification significantly increased Aβ-induced synapse damage. An understanding of the molecular mechanisms involved in the dispersal of signalling complexes is important as failure to deactivate signalling pathways can lead to pathology. This study demonstrates that esterification of cholesterol is a key factor in the dispersal of Aβ-induced signalling platforms involved in the activation of cPLA2 and synapse degeneration.
Collapse
Affiliation(s)
- Ewan West
- Department of Pathology and Pathogen Biology, Royal Veterinary College, Hawkshead Lane, North Mymms, Herts, AL9 7TA, UK
| | - Craig Osborne
- Department of Pathology and Pathogen Biology, Royal Veterinary College, Hawkshead Lane, North Mymms, Herts, AL9 7TA, UK
| | - Clive Bate
- Department of Pathology and Pathogen Biology, Royal Veterinary College, Hawkshead Lane, North Mymms, Herts, AL9 7TA, UK
| |
Collapse
|
18
|
Kim JH, Singh A, Del Poeta M, Brown DA, London E. The effect of sterol structure upon clathrin-mediated and clathrin-independent endocytosis. J Cell Sci 2017; 130:2682-2695. [PMID: 28655854 DOI: 10.1242/jcs.201731] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Accepted: 06/22/2017] [Indexed: 12/25/2022] Open
Abstract
Ordered lipid domains (rafts) in plasma membranes have been hypothesized to participate in endocytosis based on inhibition of endocytosis by removal or sequestration of cholesterol. To more carefully investigate the role of the sterol in endocytosis, we used a substitution strategy to replace cholesterol with sterols that show various raft-forming abilities and chemical structures. Both clathrin-mediated endocytosis of transferrin and clathrin-independent endocytosis of clustered placental alkaline phosphatase were measured. A subset of sterols reversibly inhibited both clathrin-dependent and clathrin-independent endocytosis. The ability of a sterol to support lipid raft formation was necessary for endocytosis. However, it was not sufficient, because a sterol lacking a 3β-OH group did not support endocytosis even though it had the ability to support ordered domain formation. Double bonds in the sterol rings and an aliphatic tail structure identical to that of cholesterol were neither necessary nor sufficient to support endocytosis. This study shows that substitution using a large number of sterols can define the role of sterol structure in cellular functions. Hypotheses for how sterol structure can similarly alter clathrin-dependent and clathrin-independent endocytosis are discussed.
Collapse
Affiliation(s)
- Ji Hyun Kim
- Dept. of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794, USA
| | - Ashutosh Singh
- Dept. of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, NY 11794, USA
| | - Maurizio Del Poeta
- Dept. of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, NY 11794, USA
| | - Deborah A Brown
- Dept. of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794, USA
| | - Erwin London
- Dept. of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794, USA
| |
Collapse
|
19
|
Skotland T, Sandvig K, Llorente A. Lipids in exosomes: Current knowledge and the way forward. Prog Lipid Res 2017; 66:30-41. [PMID: 28342835 DOI: 10.1016/j.plipres.2017.03.001] [Citation(s) in RCA: 635] [Impact Index Per Article: 90.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Revised: 03/14/2017] [Accepted: 03/21/2017] [Indexed: 12/29/2022]
Abstract
Lipids are essential components of exosomal membranes, and it is well-known that specific lipids are enriched in exosomes compared to their parent cells. In this review we discuss current knowledge about the lipid composition of exosomes. We compare published data for different lipid classes in exosomes, and what is known about their lipid species, i.e. lipid molecules with different fatty acyl groups. Moreover, we elaborate on the hypothesis about hand-shaking between the very-long-chain sphingolipids in the outer leaflet and PS 18:0/18:1 in the inner leaflet, and we propose this to be an important mechanism in membrane biology, not only for exosomes. The similarity between the lipid composition of exosomes, HIV particles, and detergent resistant membranes, used as lipid rafts models, is also discussed. Furthermore, we summarize knowledge about the role of specific lipids and lipid metabolizing enzymes on the formation and release of exosomes. Finally, the use of exosomal lipids as biomarkers and how the lipid composition of exosomes may be of importance for researchers aiming to use exosomes as drug delivery vehicles is discussed. In conclusion, we have summarized what is presently known about lipids in exosomes and identified issues that should be taken into consideration in future studies.
Collapse
Affiliation(s)
- Tore Skotland
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital-The Norwegian Radium Hospital, 0379 Oslo, Norway; Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, 0379 Oslo, Norway.
| | - Kirsten Sandvig
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital-The Norwegian Radium Hospital, 0379 Oslo, Norway; Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, 0379 Oslo, Norway; Department of Molecular Biosciences, University of Oslo, 0316 Oslo, Norway
| | - Alicia Llorente
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital-The Norwegian Radium Hospital, 0379 Oslo, Norway; Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, 0379 Oslo, Norway
| |
Collapse
|
20
|
Ceñido JF, Itin B, Stark RE, Huang YY, Oquendo MA, John Mann J, Elizabeth Sublette M. Characterization of lipid rafts in human platelets using nuclear magnetic resonance: A pilot study. Biochem Biophys Rep 2017; 10:132-6. [PMID: 28955740 DOI: 10.1016/j.bbrep.2017.03.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 02/28/2017] [Accepted: 03/15/2017] [Indexed: 11/23/2022] Open
Abstract
Lipid microdomains (‘lipid rafts’) are plasma membrane subregions, enriched in cholesterol and glycosphingolipids, which participate dynamically in cell signaling and molecular trafficking operations. One strategy for the study of the physicochemical properties of lipid rafts in model membrane systems has been the use of nuclear magnetic resonance (NMR), but until now this spectroscopic method has not been considered a clinically relevant tool. We performed a proof-of-concept study to test the feasibility of using NMR to study lipid rafts in human tissues. Platelets were selected as a cost-effective and minimally invasive model system in which lipid rafts have previously been studied using other approaches. Platelets were isolated from plasma of medication-free adult research participants (n=13) and lysed with homogenization and sonication. Lipid-enriched fractions were obtained using a discontinuous sucrose gradient. Association of lipid fractions with GM1 ganglioside was tested using HRP-conjugated cholera toxin B subunit dot blot assays. 1H high resolution magic-angle spinning nuclear magnetic resonance (HRMAS NMR) spectra obtained with single-pulse Bloch decay experiments yielded spectral linewidths and intensities as a function of temperature. Rates of lipid lateral diffusion that reported on raft size were measured with a two-dimensional stimulated echo longitudinal encode-decode NMR experiment. We found that lipid fractions at 10–35% sucrose density associated with GM1 ganglioside, a marker for lipid rafts. NMR spectra of the membrane phospholipids featured a prominent ‘centerband’ peak associated with the hydrocarbon chain methylene resonance at 1.3 ppm; the linewidth (full width at half-maximum intensity) of this ‘centerband’ peak, together with the ratio of intensities between the centerband and ‘spinning sideband’ peaks, agreed well with values reported previously for lipid rafts in model membranes. Decreasing temperature produced decreases in the 1.3 ppm peak intensity and a discontinuity at ~18 °C, for which the simplest explanation is a phase transition from Ld to Lo phases indicative of raft formation. Rates of lateral diffusion of the acyl chain lipid signal at 1.3 ppm, a quantitative measure of microdomain size, were consistent with lipid molecules organized in rafts. These results show that HRMAS NMR can characterize lipid microdomains in human platelets, a methodological advance that could be extended to other tissues in which membrane biochemistry may have physiological and pathophysiological relevance. Lipid raft properties have been studied mainly in model membranes or cell cultures. We report a novel 1H NMR approach to lipid raft characterization in human platelets. We find spectroscopy, diffusion, and phase transitions consistent with lipid rafts. NMR plus bioassays may be used to study raft-mediated cell function in human tissues.
Collapse
|
21
|
Abstract
Lipid rafts have been drawing extensive attention as a signaling platform. To investigate molecular interactions in lipid rafts, we often need to observe molecules in the plasma membranes of living cells because chemical fixation and subsequent immunostaining with divalent or multivalent antibodies may change the location of the target molecules. In this chapter, we describe how to examine dynamics of raft-associated glycosylphosphatidylinositol (GPI)-anchored receptors and interactions of the receptors with downstream signaling molecules by single-particle tracking or single-molecule imaging techniques.
Collapse
Affiliation(s)
- Kenichi G N Suzuki
- Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Institute for Frontier Medical Sciences, Kyoto University, Kyoto, 606-8507, Japan.
- National Centre for Biological Sciences (NCBS)/Institute for Stem Cell Biology and Regenerative Medicine (inStem), Bangalore, 560065, India.
| |
Collapse
|
22
|
Capponi S, Freites JA, Tobias DJ, White SH. Interleaflet mixing and coupling in liquid-disordered phospholipid bilayers. Biochim Biophys Acta 2015; 1858:354-62. [PMID: 26657692 DOI: 10.1016/j.bbamem.2015.11.024] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Revised: 11/03/2015] [Accepted: 11/21/2015] [Indexed: 01/02/2023]
Abstract
Organized as bilayers, phospholipids are the fundamental building blocks of cellular membranes and determine many of their biological functions. Interactions between the two leaflets of the bilayer (interleaflet coupling) have been implicated in the passage of information through membranes. However, physically, the meaning of interleaflet coupling is ill defined and lacks a structural basis. Using all-atom molecular dynamics simulations of fluid phospholipid bilayers of five different lipids with differing degrees of acyl-chain asymmetry, we have examined interleaflet mixing to gain insights into coupling. Reasoning that the transbilayer distribution of terminal methyl groups is an appropriate measure of interleaflet mixing, we calculated the transbilayer distributions of the acyl chain terminal methyl groups for five lipids: dioleoylphosphatidylcholine (DOPC), palmitoyloleoylphosphatidylcholine (POPC), stearoyloleoylphosphatidylcholine (SOPC), oleoylmyristoylphosphatidylcholine (OMPC), and dimyristoylphosphatidylcholine (DMPC). We observed in all cases very strong mixing across the bilayer midplane that diminished somewhat with increasing acyl-chain ordering defined by methylene order parameters. A hallmark of the interleaflet coupling idea is complementarity, which postulates that lipids with short alkyl chains in one leaflet will preferentially associate with lipids with long alkyl chains in the other leaflet. Our results suggest a much more complicated picture for thermally disordered bilayers that we call distributed complementarity, as measured by the difference in the peak positions of the sn-1 and sn-2 methyl distributions in the same leaflet.
Collapse
Affiliation(s)
- Sara Capponi
- Department of Physiology and Biophysics and Center for Biomembrane Systems, University of California at Irvine, Irvine, CA 92697, USA
| | - J Alfredo Freites
- Department of Chemistry and Center for Biomembrane Systems, University of California at Irvine, Irvine, CA 92697, USA
| | - Douglas J Tobias
- Department of Chemistry and Center for Biomembrane Systems, University of California at Irvine, Irvine, CA 92697, USA
| | - Stephen H White
- Department of Physiology and Biophysics and Center for Biomembrane Systems, University of California at Irvine, Irvine, CA 92697, USA.
| |
Collapse
|
23
|
Galmes R, Delaunay JL, Maurice M, Aït-Slimane T. Oligomerization is required for normal endocytosis/transcytosis of a GPI-anchored protein in polarized hepatic cells. J Cell Sci 2013; 126:3409-16. [PMID: 23750006 DOI: 10.1242/jcs.126250] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Targeting of glycosyl-phosphatidylinositol (GPI)-anchored proteins (GPI-APs) in polarized epithelial cells depends on their association with detergent-resistant membrane microdomains called rafts. In MDCK cells, GPI-APs associate with rafts in the trans-Golgi network and are directly delivered to the apical membrane. It has been shown that oligomerization is required for their stabilization in rafts and their apical targeting. In hepatocytes, GPI-APs are first delivered to the basolateral membrane and secondarily reach the apical membrane by transcytosis. We investigated whether oligomerization is required for raft association and apical sorting of GPI-APs in polarized HepG2 cells, and at which step of the pathway oligomerization occurs. Model proteins were wild-type GFP-GPI and a double cysteine GFP-GPI mutant, in which GFP dimerization was impaired. Unlike wild-type GFP-GPI, which was efficiently endocytosed and transcytosed to the apical surface, the double cysteine mutant was basolaterally internalized, but massively accumulated in early endosomes, and reached the bile canaliculi with delayed kinetics. The double cysteine mutant was less resistant to Triton X-100 extraction, and formed fewer high molecular weight complexes. We conclude from these results that, in hepatocytes, oligomerization plays a key role in targeting GPI-APs to the apical membrane, by increasing their affinity for rafts and allowing their transcytosis.
Collapse
Affiliation(s)
- Romain Galmes
- INSERM, UMR_S938, Centre de Recherche Saint-Antoine, Paris, France
| | | | | | | |
Collapse
|
24
|
Abstract
Single-molecule imaging is a powerful tool for the study of dynamic molecular interactions in living cell plasma membranes. Herein, we describe a single-molecule imaging microscopy technique that can be used to measure lifetimes and densities of receptor dimers and oligomers. This method can be performed using a total internal reflection fluorescent microscope equipped with one or two high-sensitivity cameras. For dual-color observation, two images obtained synchronously in different colors are spatially corrected and then overlaid. Receptors must be expressed at low density in cell plasma membranes because high-density expression (>2 molecules/μm(2)) creates difficulty for tracking individual fluorescent spots. In addition, the receptors should be labeled with highly photostable fluorophores at high efficiency because short photobleaching lifetimes and low labeling efficiency of receptors reduce the probability of detecting dimers and oligomers. In this chapter, we describe methods for observing and detecting colocalization of the individual fluorescent spots of receptors labeled with fluorophores via small tags and the estimation of true dimer and oligomer lifetimes after correction with photobleaching lifetimes of fluorophores.
Collapse
Affiliation(s)
- Kenichi G N Suzuki
- Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Kyoto, Japan; National Centre for Biological Sciences (NCBS)/Institute for Stem Cell Biology and Regenerative Medicine (inStem), Bangalore, India
| | | | | | | |
Collapse
|