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Varandas PAMM, Belinha R, Cobb AJA, Prates Ramalho JP, Segundo MA, Loura LMS, Silva EMP. Flow-based bioconjugation of coumarin phosphatidylethanolamine probes: Optimised synthesis and membrane molecular dynamics studies. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2024; 1866:184335. [PMID: 38763271 DOI: 10.1016/j.bbamem.2024.184335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Revised: 04/01/2024] [Accepted: 05/11/2024] [Indexed: 05/21/2024]
Abstract
A series of phosphatidylethanolamine fluorescent probes head-labelled with 3-carboxycoumarin was prepared by an improved bioconjugation approach through continuous flow synthesis. The established procedure, supported by a design of experiment (DoE) set-up, resulted in a significant reduction in the reaction time compared to the conventional batch method, in addition to a minor yield increase. The characterization of these probes was enhanced by an in-depth molecular dynamics (MD) study of the behaviour of a representative probe of this family, 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine labelled with 3-carboxycoumarin (POPE-COUM), in bilayers of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC)/1-stearoyl-2-linoleoyl-sn-glycero-3-phosphocholine (SLPC) 2:1, mimicking the composition of the egg yolk lecithin membranes recently used experimentally by our group to study POPE-COUM as a biomarker of the oxidation state and integrity of large unilamellar vesicles (LUVs). The MD simulations revealed that the coumarin group is oriented towards the bilayer interior, leading to a relatively internal location, in agreement with what is observed in the nitrobenzoxadiazole fluorophore of commercial head-labelled NBD-PE probes. This behaviour is consistent with the previously stated hypothesis that POPE-COUM is entirely located within the LUVs structure. Hence, the delay on the oxidation of the probe in the oxygen radical absorbance capacity (ORAC) assays performed is related with the inaccessibility of the probe until alteration of the LUV structure occurs. Furthermore, our simulations show that POPE-COUM exerts very little global and local perturbation on the host bilayer, as evaluated by key properties of the unlabelled lipids. Together, our findings establish PE-COUM as suitable fluorescent lipid analogue probes.
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Affiliation(s)
- Pedro A M M Varandas
- LAQV, REQUIMTE, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira 228, 4050-313 Porto, Portugal
| | - Ricardo Belinha
- LAQV, REQUIMTE, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira 228, 4050-313 Porto, Portugal
| | - Alexander J A Cobb
- Department of Chemistry, King's College London, 7 Trinity Street, London SE1 1DB, United Kingdom
| | - João P Prates Ramalho
- Department of Chemistry, School of Science and Technology, University of Évora, Rua Romão Ramalho 59, 7000-671 Évora, Portugal; LAQV, REQUIMTE, University of Évora, Rua Romão Ramalho 59, 7000-671 Évora, Portugal; Hercules Laboratory, University of Évora, Palácio do Vimioso, Largo Marquês de Marialva 8, 7000-809 Évora, Portugal
| | - Marcela A Segundo
- LAQV, REQUIMTE, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira 228, 4050-313 Porto, Portugal.
| | - Luís M S Loura
- Faculty of Pharmacy, University of Coimbra, 3000-548 Coimbra, Portugal; Coimbra Chemistry Center - Institute of Molecular Sciences (CQC-IMS), Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal; CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-535 Coimbra, Portugal.
| | - Eduarda M P Silva
- Associate Laboratory i4HB - Institute for Health and Bioeconomy, University Institute of Health Sciences - CESPU, 4585-116 Gandra, Portugal; UCIBIO - Applied Molecular Biosciences Unit, Translational Toxicology Research Laboratory, University Institute of Health Sciences (1H-TOXRUN, IUCS-CESPU), 4585-116 Gandra, Portugal
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2
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Borges-Araújo L, Souza PCT, Fernandes F, Melo MN. Improved Parameterization of Phosphatidylinositide Lipid Headgroups for the Martini 3 Coarse-Grain Force Field. J Chem Theory Comput 2021; 18:357-373. [PMID: 34962393 DOI: 10.1021/acs.jctc.1c00615] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Phosphoinositides are a family of membrane phospholipids that play crucial roles in membrane regulatory events. As such, these lipids are often a key part of molecular dynamics simulation studies of biological membranes, in particular of those employing coarse-grain models because of the potential long times and sizes of the involved membrane processes. Version 3 of the widely used Martini coarse-grain force field has been recently published, greatly refining many aspects of biomolecular interactions. In order to properly use it for lipid membrane simulations with phosphoinositides, we put forth the Martini 3-specific parameterization of inositol, phosphatidylinositol, and seven physiologically relevant phosphorylated derivatives of phosphatidylinositol. Compared to parameterizations for earlier Martini versions, focus was put on a more accurate reproduction of the behavior seen in both atomistic simulations and experimental studies, including the signaling-relevant phosphoinositide interaction with divalent cations. The models that we develop improve upon the conformational dynamics of phosphoinositides in the Martini force field and provide stable topologies at typical Martini time steps. They are able to reproduce experimentally known protein-binding poses as well as phosphoinositide aggregation tendencies. The latter was tested both in the presence and absence of calcium and included correct behavior of PI(4,5)P2 calcium-induced clusters, which can be of relevance for regulation.
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Affiliation(s)
- Luís Borges-Araújo
- iBB-Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Lisbon 1049-001, Portugal.,Associate Laboratory i4HB─Institute for Health and Bioeconomy, at Instituto Superior Técnico, Universidade de Lisboa, Lisbon 1049-001, Portugal.,Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, Oeiras 2780-157, Portugal
| | - Paulo C T Souza
- Molecular Microbiology and Structural Biochemistry, UMR 5086 CNRS & University of Lyon, 7 Passage du Vercors, Lyon F-69367, France
| | - Fábio Fernandes
- iBB-Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Lisbon 1049-001, Portugal.,Associate Laboratory i4HB─Institute for Health and Bioeconomy, at Instituto Superior Técnico, Universidade de Lisboa, Lisbon 1049-001, Portugal.,Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Lisbon 1049-001, Portugal
| | - Manuel N Melo
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, Oeiras 2780-157, Portugal
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3
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Cebecauer M, Amaro M, Jurkiewicz P, Sarmento MJ, Šachl R, Cwiklik L, Hof M. Membrane Lipid Nanodomains. Chem Rev 2018; 118:11259-11297. [PMID: 30362705 DOI: 10.1021/acs.chemrev.8b00322] [Citation(s) in RCA: 128] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Lipid membranes can spontaneously organize their components into domains of different sizes and properties. The organization of membrane lipids into nanodomains might potentially play a role in vital functions of cells and organisms. Model membranes represent attractive systems to study lipid nanodomains, which cannot be directly addressed in living cells with the currently available methods. This review summarizes the knowledge on lipid nanodomains in model membranes and exposes how their specific character contrasts with large-scale phase separation. The overview on lipid nanodomains in membranes composed of diverse lipids (e.g., zwitterionic and anionic glycerophospholipids, ceramides, glycosphingolipids) and cholesterol aims to evidence the impact of chemical, electrostatic, and geometric properties of lipids on nanodomain formation. Furthermore, the effects of curvature, asymmetry, and ions on membrane nanodomains are shown to be highly relevant aspects that may also modulate lipid nanodomains in cellular membranes. Potential mechanisms responsible for the formation and dynamics of nanodomains are discussed with support from available theories and computational studies. A brief description of current fluorescence techniques and analytical tools that enabled progress in lipid nanodomain studies is also included. Further directions are proposed to successfully extend this research to cells.
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Affiliation(s)
- Marek Cebecauer
- J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences , Dolejškova 3 , 18223 Prague 8 , Czech Republic
| | - Mariana Amaro
- J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences , Dolejškova 3 , 18223 Prague 8 , Czech Republic
| | - Piotr Jurkiewicz
- J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences , Dolejškova 3 , 18223 Prague 8 , Czech Republic
| | - Maria João Sarmento
- J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences , Dolejškova 3 , 18223 Prague 8 , Czech Republic
| | - Radek Šachl
- J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences , Dolejškova 3 , 18223 Prague 8 , Czech Republic
| | - Lukasz Cwiklik
- J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences , Dolejškova 3 , 18223 Prague 8 , Czech Republic
| | - Martin Hof
- J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences , Dolejškova 3 , 18223 Prague 8 , Czech Republic
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Inorganic mercury and cadmium induce rigidity in eukaryotic lipid extracts while mercury also ruptures red blood cells. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:710-717. [DOI: 10.1016/j.bbamem.2017.12.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 11/22/2017] [Accepted: 12/15/2017] [Indexed: 01/19/2023]
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Sarmento MJ, Coutinho A, Fedorov A, Prieto M, Fernandes F. Membrane Order Is a Key Regulator of Divalent Cation-Induced Clustering of PI(3,5)P 2 and PI(4,5)P 2. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:12463-12477. [PMID: 28961003 DOI: 10.1021/acs.langmuir.7b00666] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Although the evidence for the presence of functionally important nanosized phosphorylated phosphoinositide (PIP)-rich domains within cellular membranes has accumulated, very limited information is available regarding the structural determinants for compartmentalization of these phospholipids. Here, we used a combination of fluorescence spectroscopy and microscopy techniques to characterize differences in divalent cation-induced clustering of PI(4,5)P2 and PI(3,5)P2. Through these methodologies we were able to detect differences in divalent cation-induced clustering efficiency and cluster size. Ca2+-induced PI(4,5)P2 clusters are shown to be significantly larger than the ones observed for PI(3,5)P2. Clustering of PI(4,5)P2 is also detected at physiological concentrations of Mg2+, suggesting that in cellular membranes, these molecules are constitutively driven to clustering by the high intracellular concentration of divalent cations. Importantly, it is shown that lipid membrane order is a key factor in the regulation of clustering for both PIP isoforms, with a major impact on cluster sizes. Clustered PI(4,5)P2 and PI(3,5)P2 are observed to present considerably higher affinity for more ordered lipid phases than the monomeric species or than PI(4)P, possibly reflecting a more general tendency of clustered lipids for insertion into ordered domains. These results support a model for the description of the lateral organization of PIPs in cellular membranes, where both divalent cation interaction and membrane order are key modulators defining the lateral organization of these lipids.
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Affiliation(s)
- Maria J Sarmento
- Centro de Química-Física Molecular and Institute of Nanoscience and Nanotechnology, Instituto Superior Técnico, University of Lisbon , 1649-004 Lisbon, Portugal
- J. Heyrovský Inst. Physical Chemistry of the A.S.C.R. v.v.i. , 182 23 Prague, Czech Republic
| | - Ana Coutinho
- Centro de Química-Física Molecular and Institute of Nanoscience and Nanotechnology, Instituto Superior Técnico, University of Lisbon , 1649-004 Lisbon, Portugal
- Departamento de Química e Bioquímica, FCUL, University of Lisbon , 1649-004 Lisbon, Portugal
| | - Aleksander Fedorov
- Centro de Química-Física Molecular and Institute of Nanoscience and Nanotechnology, Instituto Superior Técnico, University of Lisbon , 1649-004 Lisbon, Portugal
| | - Manuel Prieto
- Centro de Química-Física Molecular and Institute of Nanoscience and Nanotechnology, Instituto Superior Técnico, University of Lisbon , 1649-004 Lisbon, Portugal
| | - Fábio Fernandes
- Centro de Química-Física Molecular and Institute of Nanoscience and Nanotechnology, Instituto Superior Técnico, University of Lisbon , 1649-004 Lisbon, Portugal
- UCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa , Campus da Caparica, 2829-516 Caparica, Portugal
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6
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Kerek EM, Prenner EJ. Inorganic cadmium affects the fluidity and size of phospholipid based liposomes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:3169-3181. [DOI: 10.1016/j.bbamem.2016.10.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2016] [Revised: 09/21/2016] [Accepted: 10/06/2016] [Indexed: 12/13/2022]
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7
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Ludolphs M, Schneeberger D, Soykan T, Schäfer J, Papadopoulos T, Brose N, Schindelin H, Steinem C. Specificity of Collybistin-Phosphoinositide Interactions: IMPACT OF THE INDIVIDUAL PROTEIN DOMAINS. J Biol Chem 2015; 291:244-54. [PMID: 26546675 DOI: 10.1074/jbc.m115.673400] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Indexed: 01/01/2023] Open
Abstract
The regulatory protein collybistin (CB) recruits the receptor-scaffolding protein gephyrin to mammalian inhibitory glycinergic and GABAergic postsynaptic membranes in nerve cells. CB is tethered to the membrane via phosphoinositides. We developed an in vitro assay based on solid-supported 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine membranes doped with different phosphoinositides on silicon/silicon dioxide substrates to quantify the binding of various CB2 constructs using reflectometric interference spectroscopy. Based on adsorption isotherms, we obtained dissociation constants and binding capacities of the membranes. Our results show that full-length CB2 harboring the N-terminal Src homology 3 (SH3) domain (CB2SH3+) adopts a closed and autoinhibited conformation that largely prevents membrane binding. This autoinhibition is relieved upon introduction of the W24A/E262A mutation, which conformationally "opens" CB2SH3+ and allows the pleckstrin homology domain to properly bind lipids depending on the phosphoinositide species with a preference for phosphatidylinositol 3-monophosphate and phosphatidylinositol 4-monophosphate. This type of membrane tethering under the control of the release of the SH3 domain of CB is essential for regulating gephyrin clustering.
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Affiliation(s)
- Michaela Ludolphs
- From the Institute of Organic and Biomolecular Chemistry, University of Göttingen, Tammannstrasse 2, 37077 Göttingen, Germany
| | - Daniela Schneeberger
- Rudolf Virchow Center for Experimental Biomedicine, University of Würzburg, Josef-Schneider-Strasse 2, 97080 Würzburg, Germany
| | - Tolga Soykan
- Department of Molecular Neurobiology, Max Planck Institute for Experimental Medicine, Hermann-Rein-Strasse 3, 37075 Göttingen, Germany, and
| | - Jonas Schäfer
- From the Institute of Organic and Biomolecular Chemistry, University of Göttingen, Tammannstrasse 2, 37077 Göttingen, Germany
| | - Theofilos Papadopoulos
- Universitätsmedizin Göttingen, Department of Molecular Biology, Humboldtallee 23, 37073 Göttingen, Germany
| | - Nils Brose
- Department of Molecular Neurobiology, Max Planck Institute for Experimental Medicine, Hermann-Rein-Strasse 3, 37075 Göttingen, Germany, and
| | - Hermann Schindelin
- Rudolf Virchow Center for Experimental Biomedicine, University of Würzburg, Josef-Schneider-Strasse 2, 97080 Würzburg, Germany
| | - Claudia Steinem
- From the Institute of Organic and Biomolecular Chemistry, University of Göttingen, Tammannstrasse 2, 37077 Göttingen, Germany,
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Slochower DR, Wang YH, Tourdot RW, Radhakrishnan R, Janmey PA. Counterion-mediated pattern formation in membranes containing anionic lipids. Adv Colloid Interface Sci 2014; 208:177-88. [PMID: 24556233 DOI: 10.1016/j.cis.2014.01.016] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Revised: 01/21/2014] [Accepted: 01/22/2014] [Indexed: 01/05/2023]
Abstract
Most lipid components of cell membranes are either neutral, like cholesterol, or zwitterionic, like phosphatidylcholine and sphingomyelin. Very few lipids, such as sphingosine, are cationic at physiological pH. These generally interact only transiently with the lipid bilayer, and their synthetic analogs are often designed to destabilize the membrane for drug or DNA delivery. However, anionic lipids are common in both eukaryotic and prokaryotic cell membranes. The net charge per anionic phospholipid ranges from -1 for the most abundant anionic lipids such as phosphatidylserine, to near -7 for phosphatidylinositol 3,4,5 trisphosphate, although the effective charge depends on many environmental factors. Anionic phospholipids and other negatively charged lipids such as lipopolysaccharides are not randomly distributed in the lipid bilayer, but are highly restricted to specific leaflets of the bilayer and to regions near transmembrane proteins or other organized structures within the plane of the membrane. This review highlights some recent evidence that counterions, in the form of monovalent or divalent metal ions, polyamines, or cationic protein domains, have a large influence on the lateral distribution of anionic lipids within the membrane, and that lateral demixing of anionic lipids has effects on membrane curvature and protein function that are important for biological control.
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Affiliation(s)
- David R Slochower
- Graduate Group in Biochemistry and Molecular Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Yu-Hsiu Wang
- Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Richard W Tourdot
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Ravi Radhakrishnan
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Paul A Janmey
- Graduate Group in Biochemistry and Molecular Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA; Departments of Physiology and Physics, University of Pennsylvania, Philadelphia, PA 19104, USA
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Jiang Z, Redfern RE, Isler Y, Ross AH, Gericke A. Cholesterol stabilizes fluid phosphoinositide domains. Chem Phys Lipids 2014; 182:52-61. [PMID: 24556334 DOI: 10.1016/j.chemphyslip.2014.02.003] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Revised: 02/06/2014] [Accepted: 02/07/2014] [Indexed: 11/19/2022]
Abstract
Local accumulation of phosphoinositides (PIPs) is an important factor for a broad range of cellular events including membrane trafficking and cell signaling. The negatively charged phosphoinositide headgroups can interact with cations or cationic proteins and this electrostatic interaction has been identified as the main phosphoinositide clustering mechanism. However, an increasing number of reports show that phosphoinositide-mediated signaling events are at least in some cases cholesterol dependent, suggesting other possible contributors to the segregation of phosphoinositides. Using fluorescence microscopy on giant unilamellar vesicles and monolayers at the air/water interface, we present data showing that cholesterol stabilizes fluid phosphoinositide-enriched phases. The interaction with cholesterol is observed for all investigated phosphoinositides (PI(4)P, PI(3,4)P2, PI(3,5)P2, PI(4,5)P2 and PI(3,4,5)P3) as well as phosphatidylinositol. We find that cholesterol is present in the phosphoinositide-enriched phase and that the resulting phase is fluid. Cholesterol derivatives modified at the hydroxyl group (cholestenone, cholesteryl ethyl ether) do not promote formation of phosphoinositide domains, suggesting an instrumental role of the cholesterol hydroxyl group in the observed cholesterol/phosphoinositide interaction. This leads to the hypothesis that cholesterol participates in an intermolecular hydrogen bond network formed among the phosphoinositide lipids. We had previously reported that the intra- and intermolecular hydrogen bond network between the phosphoinositide lipids leads to a reduction of the charge density at the phosphoinositide phosphomonoester groups (Kooijman et al., 2009). We believe that cholesterol acts as a spacer between the phosphoinositide lipids, thereby reducing the electrostatic repulsion, while participating in the hydrogen bond network, leading to its further stabilization. To illustrate the effect of phosphoinositide segregation on protein binding, we show that binding of the tumor suppressor protein PTEN to PI(5)P and PI(4,5)P2 is enhanced in the presence of cholesterol. These results provide new insights into how phosphoinositides mediate important cellular events.
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Affiliation(s)
- Zhiping Jiang
- Laboratory of Molecular Biophysics, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, United States
| | - Roberta E Redfern
- ProMedica Research Department, ProMedica Health System, Toledo, OH 43606, United States
| | - Yasmin Isler
- Academic Health Center BioRepository, ProMedica Health System, Toledo, OH 43606, United States
| | - Alonzo H Ross
- University of Massachusetts Medical School, Worcester, MA 01605, United States
| | - Arne Gericke
- Department of Chemistry and Biochemistry, Worcester Polytechnic Institute, 100 Institute Rd., Worcester, MA 01609, United States.
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Counterion-mediated cluster formation by polyphosphoinositides. Chem Phys Lipids 2014; 182:38-51. [PMID: 24440472 DOI: 10.1016/j.chemphyslip.2014.01.001] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Revised: 12/11/2013] [Accepted: 01/06/2014] [Indexed: 02/06/2023]
Abstract
Polyphosphoinositides (PPI) and in particular PI(4,5)P2, are among the most highly charged molecules in cell membranes, are important in many cellular signaling pathways, and are frequently targeted by peripheral polybasic proteins for anchoring through electrostatic interactions. Such interactions between PIP2 and proteins containing polybasic stretches depend on the physical state and the lateral distribution of PIP2 within the inner leaflet of the cell's lipid bilayer. The physical and chemical properties of PIP2 such as pH-dependent changes in headgroup ionization and area per molecule as determined by experiments together with molecular simulations that predict headgroup conformations at various ionization states have revealed the electrostatic properties and phase behavior of PIP2-containing membranes. This review focuses on recent experimental and computational developments in defining the physical chemistry of PIP2 and its interactions with counterions. Ca(2+)-induced changes in PIP2 charge, conformation, and lateral structure within the membrane are documented by numerous experimental and computational studies. A simplified electrostatic model successfully predicts the Ca(2+)-driven formation of PIP2 clusters but cannot account for the different effects of Ca(2+) and Mg(2+) on PIP2-containing membranes. A more recent computational study is able to see the difference between Ca(2+) and Mg(2+) binding to PIP2 in the absence of a membrane and without cluster formation. Spectroscopic studies suggest that divalent cation- and multivalent polyamine-induced changes in the PIP2 lateral distribution in model membrane are also different, and not simply related to the net charge of the counterion. Among these differences is the capacity of Ca(2+) but not other polycations to induce nm scale clusters of PIP2 in fluid membranes. Recent super resolution optical studies show that PIP2 forms nanoclusters in the inner leaflet of a plasma membrane with a similar size distribution as those induced by Ca(2+) in model membranes. The mechanisms by which PIP2 forms nanoclusters and other structures inside a cell remain to be determined, but the unique electrostatic properties of PIP2 and its interactions with multivalent counterions might have particular physiological relevance.
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Salvemini IL, Gau D, Reid J, Bagatolli L, Macmillan A, Moens P. Low PIP2 molar fractions induce nanometer size clustering in giant unilamellar vesicles. Chem Phys Lipids 2014; 177:51-63. [DOI: 10.1016/j.chemphyslip.2013.11.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Revised: 09/29/2013] [Accepted: 11/11/2013] [Indexed: 01/08/2023]
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12
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Sarmento MJ, Coutinho A, Fedorov A, Prieto M, Fernandes F. Ca(2+) induces PI(4,5)P2 clusters on lipid bilayers at physiological PI(4,5)P2 and Ca(2+) concentrations. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1838:822-30. [PMID: 24316170 DOI: 10.1016/j.bbamem.2013.11.020] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Revised: 11/22/2013] [Accepted: 11/26/2013] [Indexed: 01/22/2023]
Abstract
Calcium has been shown to induce clustering of PI(4,5)P2 at high and non-physiological concentrations of both the divalent ion and the phosphatidylinositol, or on supported lipid monolayers. In lipid bilayers at physiological conditions, clusters are not detected through microscopic techniques. Here, we aimed to determine through spectroscopic methodologies if calcium plays a role in PI(4,5)P2 lateral distribution on lipid bilayers under physiological conditions. Using several different approaches which included information on fluorescence quantum yield, polarization, spectra and diffusion properties of a fluorescent derivative of PI(4,5)P2 (TopFluor(TF)-PI(4,5)P2), we show that Ca(2+) promotes PI(4,5)P2 clustering in lipid bilayers at physiological concentrations of both Ca(2+) and PI(4,5)P2. Fluorescence depolarization data of TF-PI(4,5)P2 in the presence of calcium suggests that under physiological concentrations of PI(4,5)P2 and calcium, the average cluster size comprises ~15 PI(4,5)P2 molecules. The presence of Ca(2+)-induced PI(4,5)P2 clusters is supported by FCS data. Additionally, calcium mediated PI(4,5)P2 clustering was more pronounced in liquid ordered (lo) membranes, and the PI(4,5)P2-Ca(2+) clusters presented an increased affinity for lo domains. In this way, PI(4,5)P2 could function as a lipid calcium sensor and the increased efficiency of calcium-mediated PI(4,5)P2 clustering on lo domains might provide targeted nucleation sites for PI(4,5)P2 clusters upon calcium stimulus.
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Affiliation(s)
- Maria J Sarmento
- Centro de Química-Física Molecular and Institute of Nanoscience and Nanotechnology, Instituto Superior Técnico, University of Lisbon, Lisbon, Portugal
| | - Ana Coutinho
- Centro de Química-Física Molecular and Institute of Nanoscience and Nanotechnology, Instituto Superior Técnico, University of Lisbon, Lisbon, Portugal; Departamento de Química e Bioquímica, FCUL, University of Lisbon, Lisbon, Portugal
| | - Aleksander Fedorov
- Centro de Química-Física Molecular and Institute of Nanoscience and Nanotechnology, Instituto Superior Técnico, University of Lisbon, Lisbon, Portugal
| | - Manuel Prieto
- Centro de Química-Física Molecular and Institute of Nanoscience and Nanotechnology, Instituto Superior Técnico, University of Lisbon, Lisbon, Portugal
| | - Fabio Fernandes
- Centro de Química-Física Molecular and Institute of Nanoscience and Nanotechnology, Instituto Superior Técnico, University of Lisbon, Lisbon, Portugal.
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Braunger JA, Kramer C, Morick D, Steinem C. Solid supported membranes doped with PIP2: influence of ionic strength and pH on bilayer formation and membrane organization. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:14204-13. [PMID: 24199623 DOI: 10.1021/la402646k] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Phosphoinositides and in particular L-α-phosphatidylinositol-4,5-bisphosphate (PIP2) are key lipids controlling many cellular events and serve as receptors for a large number of intracellular proteins. To quantitatively analyze protein-PIP2 interactions in vitro in a time-resolved manner, planar membranes on solid substrates are highly desirable. Here, we describe an optimized protocol to form PIP2 containing planar solid supported membranes on silicon surfaces by vesicle spreading. Supported lipid bilayers (SLBs) were obtained by spreading POPC/PIP2 (92:8) small unilamellar vesicles onto hydrophilic silicon substrates at a low pH of 4.8. These membranes were capable of binding ezrin, resulting in large protein coverage as concluded from reflectometric interference spectroscopy and fluorescence microscopy. As deduced from fluorescence microscopy, only under low pH conditions, a homogeneously appearing distribution of fluorescently labeled PIP2 molecules in the membrane was achieved. Fluorescence recovery after photobleaching experiments revealed that PIP2 is not mobile in the bottom layer of the SLBs, while PIP2 is fully mobile in the top layer with diffusion coefficients of about 3 μm(2)/s. This diffusion coefficient was considerably reduced by a factor of about 3 if ezrin has been bound to PIP2 in the membrane.
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Affiliation(s)
- Julia A Braunger
- Institut für Organische und Biomolekulare Chemie, Georg-August Universität , Tammannstr. 2, 37077 Göttingen, Germany
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14
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Simple estimation of Förster Resonance Energy Transfer (FRET) orientation factor distribution in membranes. Int J Mol Sci 2012. [PMID: 23203123 PMCID: PMC3509639 DOI: 10.3390/ijms131115252] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Because of its acute sensitivity to distance in the nanometer scale, Förster resonance energy transfer (FRET) has found a large variety of applications in many fields of chemistry, physics, and biology. One important issue regarding the correct usage of FRET is its dependence on the donor-acceptor relative orientation, expressed as the orientation factor κ2. Different donor/acceptor conformations can lead to κ2 values in the 0 ≤ κ2 ≤ 4 range. Because the characteristic distance for FRET, R0, is proportional to (κ2)1/6, uncertainties in the orientation factor are reflected in the quality of information that can be retrieved from a FRET experiment. In most cases, the average value of κ2 corresponding to the dynamic isotropic limit (<κ2> = 2/3) is used for computation of R0 and hence donor-acceptor distances and acceptor concentrations. However, this can lead to significant error in unfavorable cases. This issue is more critical in membrane systems, because of their intrinsically anisotropic nature and their reduced fluidity in comparison to most common solvents. Here, a simple numerical simulation method for estimation of the probability density function of κ2 for membrane-embedded donor and acceptor fluorophores in the dynamic regime is presented. In the simplest form, the proposed procedure uses as input the most probable orientations of the donor and acceptor transition dipoles, obtained by experimental (including linear dichroism) or theoretical (such as molecular dynamics simulation) techniques. Optionally, information about the widths of the donor and/or acceptor angular distributions may be incorporated. The methodology is illustrated for special limiting cases and common membrane FRET pairs.
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15
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Loura LMS. Lateral distribution of NBD-PC fluorescent lipid analogs in membranes probed by molecular dynamics-assisted analysis of Förster Resonance Energy Transfer (FRET) and fluorescence quenching. Int J Mol Sci 2012; 13:14545-64. [PMID: 23203080 PMCID: PMC3509596 DOI: 10.3390/ijms131114545] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2012] [Revised: 10/29/2012] [Accepted: 11/01/2012] [Indexed: 01/19/2023] Open
Abstract
Förster resonance energy transfer (FRET) is a powerful tool used for many problems in membrane biophysics, including characterization of the lateral distribution of lipid components and other species of interest. However, quantitative analysis of FRET data with a topological model requires adequate choices for the values of several input parameters, some of which are difficult to obtain experimentally in an independent manner. For this purpose, atomistic molecular dynamics (MD) simulations can be potentially useful as they provide direct detailed information on transverse probe localization, relative probe orientation, and membrane surface area, all of which are required for analysis of FRET data. This is illustrated here for the FRET pairs involving 1,6-diphenylhexatriene (DPH) as donor and either 1-palmitoyl,2-(6-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino] hexanoyl)- sn-glycero-3-phosphocholine (C6-NBD-PC) or 1-palmitoyl,2-(12-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]dodecanoyl)-sn-glycero-3-phosphocholine (C12-NBD-PC) as acceptors, in fluid vesicles of 1,2-dipalmitoyl-sn-3-glycerophosphocholine (DPPC, 50 °C). Incorporation of results from MD simulations improves the statistical quality of model fitting to the experimental FRET data. Furthermore, the decay of DPH in the presence of moderate amounts of C12-NBD-PC (>0.4 mol%) is consistent with non-random lateral distribution of the latter, at variance with C6-NBD-PC, for which aggregation is ruled out up to 2.5 mol% concentration. These conclusions are supported by analysis of NBD-PC fluorescence self-quenching. Implications regarding the relative utility of these probes in membrane studies are discussed.
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Affiliation(s)
- Luís M S Loura
- Faculty of Pharmacy, University of Coimbra, Health Sciences Campus, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal.
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16
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Loura LMS, Prieto M. Lateral Membrane Heterogeneity Probed by FRET Spectroscopy and Microscopy. SPRINGER SERIES ON FLUORESCENCE 2012. [DOI: 10.1007/4243_2012_59] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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17
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Loura LMS, Prieto M. FRET in Membrane Biophysics: An Overview. Front Physiol 2011; 2:82. [PMID: 22110442 PMCID: PMC3216123 DOI: 10.3389/fphys.2011.00082] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2011] [Accepted: 10/26/2011] [Indexed: 12/31/2022] Open
Abstract
Förster resonance energy transfer (FRET), in most applications used as a “spectroscopic ruler,” allows an easy determination of the donor-acceptor intermolecular distance. However, the situation becomes complex in membranes, since around each donor there is an ensemble of acceptors at non-correlated distances. In this review, state-of-the-art methodologies for this situation are presented, usually involving time-resolved data and model fitting. This powerful approach can be used to study the occurrence of phase separation (“rafts” or other type of domains), allowing their detection as well as size evaluation. Formalisms for studying lipid–protein and protein–protein interactions according to specific topologies are also addressed. The advantages and added complexity of a specific type of FRET (energy homotransfer or energy migration) are described, as well as applications of FRET under the microscope.
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Affiliation(s)
- Luís M S Loura
- Faculdade de Farmácia, Universidade de Coimbra Coimbra, Portugal
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18
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Baumann MK, Swann MJ, Textor M, Reimhult E. Pleckstrin Homology-Phospholipase C-δ1 Interaction with Phosphatidylinositol 4,5-Bisphosphate Containing Supported Lipid Bilayers Monitored in Situ with Dual Polarization Interferometry. Anal Chem 2011; 83:6267-74. [DOI: 10.1021/ac2009178] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Martina K. Baumann
- Department of Materials, Laboratory for Surface Science and Technology (LSST), ETH Zurich, Wolfgang-Pauli-Strasse 10, CH-8093 Zurich, Switzerland
| | - Marcus J. Swann
- Farfield Group, Farfield House, Southmere Court, Electra Way, Crewe Business Park, Crewe CW1 6GU, United Kingdom
| | - Marcus Textor
- Department of Materials, Laboratory for Surface Science and Technology (LSST), ETH Zurich, Wolfgang-Pauli-Strasse 10, CH-8093 Zurich, Switzerland
| | - Erik Reimhult
- Department of Materials, Laboratory for Surface Science and Technology (LSST), ETH Zurich, Wolfgang-Pauli-Strasse 10, CH-8093 Zurich, Switzerland
- Department of Nanobiotechnology, University of Natural Resources and Life Sciences Vienna, Muthgasse 11, A-1190 Vienna, Austria
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19
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Characterization of supported lipid bilayers incorporating the phosphoinositides phosphatidylinositol 4,5-biphosphate and phosphoinositol-3,4,5-triphosphate by complementary techniques. Biointerphases 2011; 5:114-9. [PMID: 21219032 DOI: 10.1116/1.3516485] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Phosphoinositides are involved in a large number of processes in cells and it is very demanding to study individual protein-lipid interactions in vivo due to their rapid turnover and involvement in simultaneous events. Supported lipid bilayers (SLBs) containing controlled amounts of phosphoinositides provide a defined model system where important specific recognition events involving phosphoinositides can be systematically investigated using surface sensitive analytical techniques. The authors have demonstrated the formation and characterized the assembly kinetics of SLBs incorporating phosphatidylinositol 4,5-biphosphate (PIP(2); 1, 5, and 10 wt %) and phosphoinositol-3,4,5-triphosphate (1 wt %) using the quartz crystal microbalance with dissipation monitoring and fluorescence recovery after photobleaching. An increased fraction of phosphoinositides led to a higher barrier to liposome fusion, but full fluidity for the phosphatidylcholine lipids in the formed SLB. Significantly, the majority of phosphoinositides were shown to be immobile. X-ray photoelectron spectroscopy was used for the first time to verify that the PIP(2) fraction of lipids in the SLB scales linearly with the amount mixed in from stock solutions.
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20
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Dietrich U, Krüger P, Käs JA. Structural investigation on the adsorption of the MARCKS peptide on anionic lipid monolayers - effects beyond electrostatic. Chem Phys Lipids 2011; 164:266-75. [PMID: 21376024 DOI: 10.1016/j.chemphyslip.2011.02.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2010] [Revised: 02/16/2011] [Accepted: 02/17/2011] [Indexed: 11/25/2022]
Abstract
The presence of charged lipids in the cell membrane constitutes the background for the interaction with numerous membrane proteins. As a result, the valence of the lipids plays an important role concerning their lateral organization in the membrane and therefore the very manner of this interaction. This present study examines this aspect, particularly regarding to the interaction of the anionic lipid DPPS with the highly basic charged effector domain of the MARCKS protein, examined in monolayer model systems. Film balance, fluorescence microscopy and X-ray reflection/diffraction measurements were used to study the behavior of DPPS in a mixture with DPPC for its dependance on the presence of MARCKS (151-175). In the mixed monolayer, both lipids are completely miscible therefore DPPS is incorporated in the ordered crystalline DPPC domains as well. The interaction of MARCKS peptide with the mixed monolayer leads to the formation of lipid/peptide clusters causing an elongation of the serine group of the DPPS up to 7Å in direction to surface normal into the subphase. The large cationic charge of the peptide pulls out the serine group of the interface which simultaneously causes an elongation of the phosphodiester group of the lipid fraction too. The obtained results were used to compare the interaction of MARCKS peptide with the polyvalent PIP(2) in mixed monolayers. On this way we surprisingly find out, that the relative small charge difference of the anionic lipids causes a significant different interaction with MARCKS (151-175). The lateral arrangement of the anionic lipids depends on their charge values and determines the diffusion of the electrostatic binding clusters within the membrane.
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Affiliation(s)
- Undine Dietrich
- Division of Soft Matter Physics, Leipzig University, Linnstrasse, Germany.
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21
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Ohki S, Müller M, Arnold K, Ohshima H. Surface potential of phosphoinositide membranes: comparison between theory and experiment. Colloids Surf B Biointerfaces 2010; 79:210-8. [PMID: 20435450 DOI: 10.1016/j.colsurfb.2010.03.052] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2010] [Accepted: 03/31/2010] [Indexed: 10/19/2022]
Abstract
Surface potential of lipid membranes made of phosphatidylcholine (PC) and one of the phosphoinositides (PPI); PI, PIP or PIP(2), was studied by using the electrophoretic mobility of these lipid membrane vesicles, and a theoretical model of the surface potential developed for these membranes containing PPIs. By using the measured zeta-potential for the PI/PC membranes and a well-known surface potential theory, the inositol ring of the PI molecule was found to extend into the aqueous phase approximately normal to the membrane surface for various PI/PC ratios investigated. The outer edge of the inositol ring is located at about 5.2A from the phosphate group conjugated with the glycerol of the phospholipids. The inositol group was slightly tilted from the membrane normal direction. For both PIP/PC and PIP(2)/PC membranes, the analyses of surface potential using the measured zeta-potential values and the surface potential theory which was developed for these membranes gave consistent results with respect to the slipping layer distance from the second surface charge layer. The conclusion is that the experimental data can be fairly well resolved by using a linearized Poisson-Boltzmann surface potential equation set up for a PPI/PC membrane model up to a certain concentration of PPI in PC membranes. Our theoretical model made for these membrane surface potentials seems to be reasonable for analysis of electrical surface phenomena for these PPI/PC membranes containing small concentrations of PPI molecules.
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Affiliation(s)
- Shinpei Ohki
- Department of Physiology & Biophysics, State University of New York at Buffalo, Buffalo, NY, USA.
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22
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Loura LMS, Prieto M, Fernandes F. Quantification of protein-lipid selectivity using FRET. EUROPEAN BIOPHYSICS JOURNAL : EBJ 2010; 39:565-78. [PMID: 20238256 PMCID: PMC2841278 DOI: 10.1007/s00249-009-0532-z] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/15/2009] [Revised: 07/30/2009] [Accepted: 08/04/2009] [Indexed: 12/11/2022]
Abstract
Membrane proteins exhibit different affinities for different lipid species, and protein-lipid selectivity regulates the membrane composition in close proximity to the protein, playing an important role in the formation of nanoscale membrane heterogeneities. The sensitivity of Förster resonance energy transfer (FRET) for distances of 10 A up to 100 A is particularly useful to retrieve information on the relative distribution of proteins and lipids in the range over which protein-lipid selectivity is expected to influence membrane composition. Several FRET-based methods applied to the quantification of protein-lipid selectivity are described herein, and different formalisms applied to the analysis of FRET data for particular geometries of donor-acceptor distribution are critically assessed.
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Affiliation(s)
- Luís M. S. Loura
- Faculdade de Farmácia, Universidade de Coimbra, Pólo das Ciências da Saúde, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal
- Centro de Química de Évora, Rua Romão Ramalho, 59, 7000-671 Evora, Portugal
| | - Manuel Prieto
- Centro de Química Física Molecular and Institute of Nanosciences and Nanotechnologies, Complexo I, Instituto Superior Técnico, Av. Rovisco Pais, 1049-001 Lisbon, Portugal
| | - Fábio Fernandes
- Department of Membrane Biophysics, Max-Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
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23
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Membrane microheterogeneity: Förster resonance energy transfer characterization of lateral membrane domains. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2009; 39:589-607. [DOI: 10.1007/s00249-009-0547-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2009] [Revised: 09/14/2009] [Accepted: 09/24/2009] [Indexed: 01/20/2023]
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24
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Kooijman EE, King KE, Gangoda M, Gericke A. Ionization Properties of Phosphatidylinositol Polyphosphates in Mixed Model Membranes. Biochemistry 2009; 48:9360-71. [DOI: 10.1021/bi9008616] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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25
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Profilin interaction with phosphatidylinositol (4,5)-bisphosphate destabilizes the membrane of giant unilamellar vesicles. Biophys J 2009; 96:5112-21. [PMID: 19527671 DOI: 10.1016/j.bpj.2009.03.034] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2008] [Revised: 03/23/2009] [Accepted: 03/24/2009] [Indexed: 11/22/2022] Open
Abstract
Profilin, a small cytoskeletal protein, and phosphatidylinositol (4,5)-bisphosphate [PI(4,5)P2] have been implicated in cellular events that alter the cell morphology, such as endocytosis, cell motility, and formation of the cleavage furrow during cytokinesis. Profilin has been shown to interact with PI(4,5)P2, but the role of this interaction is still poorly understood. Using giant unilamellar vesicles (GUVs) as a simple model of the cell membrane, we investigated the interaction between profilin and PI(4,5)P2. A number and brightness analysis demonstrated that in the absence of profilin, molar ratios of PI(4,5)P2 above 4% result in lipid demixing and cluster formations. Furthermore, adding profilin to GUVs made with 1% PI(4,5)P2 leads to the formation of clusters of both profilin and PI(4,5)P2. However, due to the self-quenching of the dipyrrometheneboron difluoride-labeled PI(4,5)P2, we were unable to determine the size of these clusters. Finally, we show that the formation of these clusters results in the destabilization and deformation of the GUV membrane.
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26
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Garg S, Tang JX, Rühe J, Naumann CA. Actin-induced perturbation of PS lipid-cholesterol interaction: A possible mechanism of cytoskeleton-based regulation of membrane organization. J Struct Biol 2009; 168:11-20. [PMID: 19366633 DOI: 10.1016/j.jsb.2009.04.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2008] [Revised: 04/02/2009] [Accepted: 04/03/2009] [Indexed: 01/27/2023]
Abstract
To obtain insight into the potential role of the cytoskeleton on lipid mixing behavior in plasma membranes, the current study explores the influence of physisorbed actin filaments (F-actin) on lipid-lipid phase separations in planar model membrane systems containing raft-mimicking lipid mixtures of well-defined compositions using a complementary experimental approach of epifluorescence microscopy, fluorescence anisotropy, wide-field single molecule fluorescence microscopy, and interfacial rheometry. In particular, we have explored the impact of F-actin on cholesterol (CHOL)-phospholipid interactions, which are considered important for the formation of CHOL-enriched lipid raft domains. By using epifluorescence microscopy, we show that physisorbed filamentous actin (F-actin) alters the domain size of lipid-lipid phase separations in the presence of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylserine (POPS) and cholesterol (CHOL). In contrast, no actin-induced modification in lipid-lipid phase separations is observed in the absence of POPS or when POPS is replaced by another anionic lipid, 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylglycerol (POPG). Wide-field single molecule fluorescence microscopy on binary lipid mixtures indicate that PS and PG lipids show similar electrostatic interactions with physisorbed actin filaments. Complementary fluorescence anisotropy experiments on binary PS lipid-containing lipid mixtures are provided to illustrate the actin-induced segregation of anionic lipids. The similarity of electrostatic interactions between actin and both anionic lipids suggests that the observed differences in actin-mediated perturbations of lipid phase separations are caused by distinct PS lipid-CHOL versus PG lipid-CHOL interactions. We hypothesize that the actin cytoskeleton and some peripheral membrane proteins may alter lipid-lipid phase separations in plasma membranes in a similar way by interacting with PS lipids.
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Affiliation(s)
- S Garg
- Indiana University, Department of Chemistry and Chemical Biology, Indianapolis, 46202-3274, USA
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27
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Dietrich U, Krüger P, Gutberlet T, Käs JA. Interaction of the MARCKS peptide with PIP2 in phospholipid monolayers. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2009; 1788:1474-81. [PMID: 19362071 DOI: 10.1016/j.bbamem.2009.04.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2009] [Revised: 03/15/2009] [Accepted: 04/01/2009] [Indexed: 11/17/2022]
Abstract
In this present work we have studied the effect of MARCKS (151-175) peptide on a mixed DPPC/PIP2 monolayer. By means of film balance, fluorescence microscopy, x-ray reflection/diffraction and neutron reflection measurements we detected changes in the lateral organization of the monolayer and changes in the perpendicular orientation of the PIP2 molecules depending on the presence of MARCKS (151-175) peptide in the subphase. In the mixed monolayer, the PIP2 molecules are distributed uniformly in the disordered phase of the monolayer, whereas the PI(4,5) groups elongate up to 10 A below the phosphodiester groups. This elongation forms the precondition for the electrostatic interaction of the MARCKS peptide with the PIP2 molecules. Due to the enrichment of PIP2 in the disordered phase, the interaction with the peptide occurs primarily in this phase, causing the PI(4,5) groups to tilt toward the monolayer interface.
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Affiliation(s)
- Undine Dietrich
- Division of Soft Matter Physics, Faculty for Physics and Earth Sciences, University of Leipzig, Linnéstr. 5, D-04103 Leipzig, Germany.
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28
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Loura LM, de Almeida RF, Silva LC, Prieto M. FRET analysis of domain formation and properties in complex membrane systems. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2009; 1788:209-24. [DOI: 10.1016/j.bbamem.2008.10.012] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2008] [Revised: 10/16/2008] [Accepted: 10/16/2008] [Indexed: 12/27/2022]
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29
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Carvalho K, Ramos L, Roy C, Picart C. Giant unilamellar vesicles containing phosphatidylinositol(4,5)bisphosphate: characterization and functionality. Biophys J 2008; 95:4348-60. [PMID: 18502807 PMCID: PMC2567945 DOI: 10.1529/biophysj.107.126912] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2007] [Accepted: 05/01/2008] [Indexed: 01/28/2023] Open
Abstract
Biomimetic systems such as giant unilamellar vesicles (GUVs) are increasingly used for studying protein/lipid interactions due to their size (similar to that of cells) and to their ease of observation by light microscopy techniques. Biophysicists have begun to complexify GUVs to investigate lipid/protein interactions. In particular, composite GUVs have been designed that incorporate lipids that play important physiological roles in cellulo, such as phosphoinositides and among those the most abundant one, phosphatidylinositol(4,5)bisphosphate (PIP2). Fluorescent lipids are often used as tracers to observe GUV membranes by microscopy but they can not bring quantitative information about the insertion of unlabeled lipids. In this study, we carried out zeta-potential measurements to prove the effective incorporation of PIP2 as well as that of phosphatidylserine in the membrane of GUVs prepared by electroformation and to follow the stability of PIP2-containing GUVs. Using confocal microscopy, we found that long-chain (C16) fluorescent PIP2 analogs used as tracers (0.1% of total lipids) show a uniform distribution in the membrane whereas PIP2 antibodies show PIP2 clustering. However, the clustering effect, which is emphasized when tertiary antibodies are used in addition to secondary ones to enhance the size of the detection complex, is artifactual. We showed that divalent ions (Ca2+ and Mg2+) can induce aggregation of PIP2 in the membrane depending on their concentration. Finally, the interaction of ezrin with PIP2-containing GUVs was investigated. Using either labeled ezrin and unlabeled GUVs or both labeled ezrin and GUVs, we showed that clusters of PIP2 and proteins are formed.
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Affiliation(s)
- Kévin Carvalho
- DIMNP, Dynamique des Interactions Membranaires Normales et Pathologiques, Centre National de la Recherche Scientifique, UMR 5235, Université Montpellier II et I, Montpellier, France
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30
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Nickel W, Seedorf M. Unconventional Mechanisms of Protein Transport to the Cell Surface of Eukaryotic Cells. Annu Rev Cell Dev Biol 2008; 24:287-308. [PMID: 18590485 DOI: 10.1146/annurev.cellbio.24.110707.175320] [Citation(s) in RCA: 202] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Walter Nickel
- Heidelberg University Biochemistry Center (BZH) 69120 Heidelberg, Germany
| | - Matthias Seedorf
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), 69120 Heidelberg, Germany;
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31
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Epand RM. Proteins and cholesterol-rich domains. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2008; 1778:1576-82. [DOI: 10.1016/j.bbamem.2008.03.016] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2007] [Revised: 03/19/2008] [Accepted: 03/24/2008] [Indexed: 12/21/2022]
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32
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Temmerman K, Ebert AD, Müller HM, Sinning I, Tews I, Nickel W. A direct role for phosphatidylinositol-4,5-bisphosphate in unconventional secretion of fibroblast growth factor 2. Traffic 2008; 9:1204-17. [PMID: 18419755 DOI: 10.1111/j.1600-0854.2008.00749.x] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Fibroblast growth factor 2 (FGF-2) is a mitogen that is exported from cells by an endoplasmic reticulum/Golgi-independent secretory pathway. Recent findings have shown that FGF-2 export occurs by direct translocation from the cytoplasm across the plasma membrane into the extracellular space. Here, we report that FGF-2 contains a binding site for phosphatidylinositol-4,5-bisphosphate [PI(4,5)P(2)], the principal phosphoinositide species associated with plasma membranes. Intriguingly, in the context of a lipid bilayer, the interaction between FGF-2 and PI(4,5)P(2) is shown to depend on a lipid background that resembles plasma membranes. We show that the interaction with PI(4,5)P(2) is critically important for FGF-2 secretion as experimental conditions reducing cellular levels of PI(4,5)P(2) resulted in a substantial drop in FGF-2 export efficiency. Likewise, we have identified FGF-2 variant forms deficient for binding to PI(4,5)P(2) that were found to be severely impaired with regard to export efficiency. These data show that a transient interaction with PI(4,5)P(2) associated with the inner leaflet of plasma membranes represents the initial step of the unconventional secretory pathway of FGF-2.
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Affiliation(s)
- Koen Temmerman
- Heidelberg University Biochemistry Center, Im Neuenheimer Feld 328, 69120 Heidelberg, Germany
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Golebiewska U, Nyako M, Woturski W, Zaitseva I, McLaughlin S. Diffusion coefficient of fluorescent phosphatidylinositol 4,5-bisphosphate in the plasma membrane of cells. Mol Biol Cell 2008; 19:1663-9. [PMID: 18256277 PMCID: PMC2291420 DOI: 10.1091/mbc.e07-12-1208] [Citation(s) in RCA: 117] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2007] [Revised: 01/10/2008] [Accepted: 01/24/2008] [Indexed: 11/11/2022] Open
Abstract
Phosphatidylinositol 4,5-bisphosphate (PIP(2)) controls a surprisingly large number of processes in cells. Thus, many investigators have suggested that there might be different pools of PIP(2) on the inner leaflet of the plasma membrane. If a significant fraction of PIP(2) is bound electrostatically to unstructured clusters of basic residues on membrane proteins, the PIP(2) diffusion constant, D, should be reduced. We microinjected micelles of Bodipy TMR-PIP(2) into cells, and we measured D on the inner leaflet of fibroblasts and epithelial cells by using fluorescence correlation spectroscopy. The average +/- SD value from all cell types was D = 0.8 +/- 0.2 microm(2)/s (n = 218; 25 degrees C). This is threefold lower than the D in blebs formed on Rat1 cells, D = 2.5 +/- 0.8 microm(2)/s (n = 26). It is also significantly lower than the D in the outer leaflet or in giant unilamellar vesicles and the diffusion coefficient for other lipids on the inner leaflet of these cell membranes. The simplest interpretation is that approximately two thirds of the PIP(2) on inner leaflet of these plasma membranes is bound reversibly.
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Affiliation(s)
- Urszula Golebiewska
- Department of Physiology and Biophysics, Health Science Center, Stony Brook University, Stony Brook, NY 11794-8661
| | - Marian Nyako
- Department of Physiology and Biophysics, Health Science Center, Stony Brook University, Stony Brook, NY 11794-8661
| | - William Woturski
- Department of Physiology and Biophysics, Health Science Center, Stony Brook University, Stony Brook, NY 11794-8661
| | - Irina Zaitseva
- Department of Physiology and Biophysics, Health Science Center, Stony Brook University, Stony Brook, NY 11794-8661
| | - Stuart McLaughlin
- Department of Physiology and Biophysics, Health Science Center, Stony Brook University, Stony Brook, NY 11794-8661
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Blin G, Margeat E, Carvalho K, Royer CA, Roy C, Picart C. Quantitative analysis of the binding of ezrin to large unilamellar vesicles containing phosphatidylinositol 4,5 bisphosphate. Biophys J 2007; 94:1021-33. [PMID: 17827228 PMCID: PMC2186265 DOI: 10.1529/biophysj.107.110213] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
The plasma membrane-cytoskeleton interface is a dynamic structure participating in a variety of cellular events. Among the proteins involved in the direct linkage between the cytoskeleton and the plasma membrane is the ezrin/radixin/moesin (ERM) family. The FERM (4.1 ezrin/radixin/moesin) domain in their N-terminus contains a phosphatidylinositol 4,5 bisphosphate (PIP(2)) (membrane) binding site whereas their C-terminus binds actin. In this work, our aim was to quantify the interaction of ezrin with large unilamellar vesicles (LUVs) containing PIP(2). For this purpose, we produced human recombinant ezrin bearing a cysteine residue at its C-terminus for subsequent labeling with Alexa488 maleimide. The functionality of labeled ezrin was checked by comparison with that of wild-type ezrin. The affinity constant between ezrin and LUVs was determined by cosedimentation assays and fluorescence correlation spectroscopy. The affinity was found to be approximately 5 microM for PIP(2)-LUVs and 20- to 70-fold lower for phosphatidylserine-LUVs. These results demonstrate, as well, that the interaction between ezrin and PIP(2)-LUVs is not cooperative. Finally, we found that ezrin FERM domain (area of approximately 30 nm(2)) binding to a single PIP(2) can block access to neighboring PIP(2) molecules and thus contributes to lower the accessible PIP(2) concentration. In addition, no evidence exists for a clustering of PIP(2) induced by ezrin addition.
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Affiliation(s)
- Guillaume Blin
- DIMNP, Universités Montpellier II et I, CNRS, Montpellier cedex 05, France
| | - Emmanuel Margeat
- Institut National de la Sante et de la Recherche Medicale Unité 554, and Université Montpellier, Centre National de Recherche Scientifique, UMR 5048, Centre de Biochimie Structurale, Montpellier, France
| | - Kévin Carvalho
- DIMNP, Universités Montpellier II et I, CNRS, Montpellier cedex 05, France
| | - Catherine A. Royer
- Institut National de la Sante et de la Recherche Medicale Unité 554, and Université Montpellier, Centre National de Recherche Scientifique, UMR 5048, Centre de Biochimie Structurale, Montpellier, France
| | - Christian Roy
- DIMNP, Universités Montpellier II et I, CNRS, Montpellier cedex 05, France
| | - Catherine Picart
- DIMNP, Universités Montpellier II et I, CNRS, Montpellier cedex 05, France
- Address reprint requests to Catherine Picart.
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Abstract
Phosphatidylinositol 4,5-bisphosphate (PIP(2))-mediated signalling is a new and rapidly developing area in the field of cellular signal transduction. With the extensive and growing list of PIP(2)-sensitive membrane proteins (many of which are ion channels and transporters) and multiple signals affecting plasma membrane PIP(2) levels, the question arises as to the cellular mechanisms that confer specificity to PIP(2)-mediated signalling. In this review we critically consider two major hypotheses for such possible mechanisms: (i) clustering of PIP(2) in membrane microdomains with restricted lateral diffusion, a hypothesis providing a mechanism for spatial segregation of PIP(2) signals and (ii) receptor-specific buffering of the global plasma membrane PIP(2) pool via Ca(2+)-mediated stimulation of PIP(2) synthesis or release, a concept allowing for receptor-specific signalling with free lateral diffusion of PIP(2). We also discuss several other technical and conceptual intricacies of PIP(2)-mediated signalling.
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Affiliation(s)
- Nikita Gamper
- Institute of Membrane and Systems Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK.
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