1
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Bobkov D, Semenova S. Impact of lipid rafts on transient receptor potential channel activities. J Cell Physiol 2022; 237:2034-2044. [PMID: 35014032 DOI: 10.1002/jcp.30679] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Revised: 12/06/2021] [Accepted: 12/23/2021] [Indexed: 11/06/2022]
Abstract
Members of the transient receptor potential (TRP) superfamily are cation channels that are expressed in nearly every mammalian cell type and respond as cellular sensors to various environmental stimuli. Light, pressure, osmolarity, temperature, and other stimuli can induce TRP calcium conductivity and correspondingly trigger many signaling processes in cells. Disruption of TRP channel activity, as a rule, harms cellular function. Despite numerous studies, the mechanisms of TRP channel regulation are not yet sufficiently clear, in part, because TRP channels are regulated by a broad set of ligands having diverse physical and chemical features. It is now known that some TRP members are located in membrane microdomains termed lipid rafts. Moreover, interaction between specific raft-associated lipids with channels may be a key regulation mechanism. This review examines recent findings related to the roles of lipid rafts in regulation of TRP channel activity. The mechanistic events of channel interactions with the main lipid raft constituent, cholesterol, are being clarified. Better understanding of mechanisms behind such interactions would help establish the key elements of TRP channel regulation and hence allow control of cellular responses to environmental stimuli.
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Affiliation(s)
- Danila Bobkov
- Laboratory of Ionic Mechanisms of Cell Signaling, Institute of Cytology, Russian Academy of Sciences, St. Petersburg, Russia
| | - Svetlana Semenova
- Laboratory of Ionic Mechanisms of Cell Signaling, Institute of Cytology, Russian Academy of Sciences, St. Petersburg, Russia
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2
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Hai X, Zhou J, Liu G. Construction of immune/Creutzfeldt-Jakob disease-related gene coexpression network to predict biomarkers. Eur J Neurol 2021; 29:47-58. [PMID: 34390074 DOI: 10.1111/ene.15063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 07/30/2021] [Indexed: 11/29/2022]
Abstract
BACKGROUND AND PURPOSE Creutzfeldt-Jakob disease (CJD) is a transmissible spongiform encephalopathy characterized by rapid onset and high mortality. Despite considerable progress in the treatment and diagnosis of CJD, patient prognosis remains poor. Many studies have found that the immune response is associated with the pathophysiology of CJD. However, few studies have reported coexpression correlations between genes associated with CJD and the immune response. This study was undertaken to construct a network of coexpressed immune- and CJD-related genes that may reveal new biomarkers and therapeutic targets for CJD. METHODS Gene expression data from 11 CJD patients and 10 nonneurological controls were obtained from the Gene Expression Omnibus database. High-confidence protein-protein interaction (PPI) data were downloaded from the Human Protein Reference Database, and gene expression data of immune- and CJD-associated genes were downloaded from the AmiGo16 and DisGeNET databases, respectively. An immune/CJD-related expression network was constructed based on Pearson correlation coefficients and PPI networks, and a CJD-directed neighbour coexpression network was extracted, in which we compared the gene expression patterns and correlations between different groups. The samples were classified using CJD-specific modules, and differentially expressed genes (DEGs) between the CJD and nonneurological controls groups were identified within the CJD-specific modules. Further functional analysis was performed using Kyoto Encyclopaedia of Genes and Genomes (KEGG) enrichment analysis of genes in each CJD-specific module. RESULTS We constructed an immune/CJD-related coexpression gene network comprising 2007 nodes and 5268 edges, with immune-associated genes occupying important positions in the network. In the CJD-directed neighbour coexpression network, immune-associated genes exhibited the highest coexpression level with their interacting genes. Results from Pearson correlation analysis showed that most of the CJD-associated genes were positively correlated with immune-associated genes. Screening for CJD-specific modules identified MAPK1, CASP3, APP, MAPT, SNCA, and YWHAH, indicating a close connection between CJD and the immune response. Analyses of coexpression status and expression level of CJD-specific genes revealed a very high coexpression pattern for any two genes, with most genes being DEGs. Finally, KEGG enrichment analyses of all CJD-specific genes showed that the pathophysiology of CJD is closely related to infection and the immune response. CONCLUSIONS Our coexpression network analysis revealed a close connection between CJD- and immune-associated genes, and we identified six CJD-specific modules. Biological function analysis of CJD-specific module genes revealed that immune responses are associated with CJD pathophysiology and may provide novel diagnostic and therapeutic biomarkers for this disease.
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Affiliation(s)
- Xiaoou Hai
- Department of Pathogenic Biology, College of Basic Medical Sciences, Shenyang Medical College, Shenyang, China
| | - Jiaming Zhou
- Franklin and Marshall College, Lancaster, Pennsylvania, USA
| | - Guangyan Liu
- Department of Pathogenic Biology, College of Basic Medical Sciences, Shenyang Medical College, Shenyang, China
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3
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Furlan AL, Laurin Y, Botcazon C, Rodríguez-Moraga N, Rippa S, Deleu M, Lins L, Sarazin C, Buchoux S. Contributions and Limitations of Biophysical Approaches to Study of the Interactions between Amphiphilic Molecules and the Plant Plasma Membrane. PLANTS 2020; 9:plants9050648. [PMID: 32443858 PMCID: PMC7285231 DOI: 10.3390/plants9050648] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 05/07/2020] [Accepted: 05/15/2020] [Indexed: 12/20/2022]
Abstract
Some amphiphilic molecules are able to interact with the lipid matrix of plant plasma membranes and trigger the immune response in plants. This original mode of perception is not yet fully understood and biophysical approaches could help to obtain molecular insights. In this review, we focus on such membrane-interacting molecules, and present biophysically grounded methods that are used and are particularly interesting in the investigation of this mode of perception. Rather than going into overly technical details, the aim of this review was to provide to readers with a plant biochemistry background a good overview of how biophysics can help to study molecular interactions between bioactive amphiphilic molecules and plant lipid membranes. In particular, we present the biomimetic membrane models typically used, solid-state nuclear magnetic resonance, molecular modeling, and fluorescence approaches, because they are especially suitable for this field of research. For each technique, we provide a brief description, a few case studies, and the inherent limitations, so non-specialists can gain a good grasp on how they could extend their toolbox and/or could apply new techniques to study amphiphilic bioactive compound and lipid interactions.
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Affiliation(s)
- Aurélien L. Furlan
- Laboratoire de Biophysique Moléculaire aux Interfaces, Gembloux Agro-Bio Tech, TERRA Research Center, Université de Liège, B5030 Gembloux, Belgium; (A.L.F.); (Y.L.); (M.D.); (L.L.)
| | - Yoann Laurin
- Laboratoire de Biophysique Moléculaire aux Interfaces, Gembloux Agro-Bio Tech, TERRA Research Center, Université de Liège, B5030 Gembloux, Belgium; (A.L.F.); (Y.L.); (M.D.); (L.L.)
- Unité de Génie Enzymatique et Cellulaire, UMR 7025 CNRS/UPJV/UTC, Université de Picardie Jules Verne, 80039 Amiens, France; (C.B.); (N.R.-M.); (C.S.)
| | - Camille Botcazon
- Unité de Génie Enzymatique et Cellulaire, UMR 7025 CNRS/UPJV/UTC, Université de Picardie Jules Verne, 80039 Amiens, France; (C.B.); (N.R.-M.); (C.S.)
- Unité de Génie Enzymatique et Cellulaire, UMR 7025 CNRS/UPJV/UTC, Université de Technologie de Compiègne, 60200 Compiègne, France;
| | - Nely Rodríguez-Moraga
- Unité de Génie Enzymatique et Cellulaire, UMR 7025 CNRS/UPJV/UTC, Université de Picardie Jules Verne, 80039 Amiens, France; (C.B.); (N.R.-M.); (C.S.)
| | - Sonia Rippa
- Unité de Génie Enzymatique et Cellulaire, UMR 7025 CNRS/UPJV/UTC, Université de Technologie de Compiègne, 60200 Compiègne, France;
| | - Magali Deleu
- Laboratoire de Biophysique Moléculaire aux Interfaces, Gembloux Agro-Bio Tech, TERRA Research Center, Université de Liège, B5030 Gembloux, Belgium; (A.L.F.); (Y.L.); (M.D.); (L.L.)
| | - Laurence Lins
- Laboratoire de Biophysique Moléculaire aux Interfaces, Gembloux Agro-Bio Tech, TERRA Research Center, Université de Liège, B5030 Gembloux, Belgium; (A.L.F.); (Y.L.); (M.D.); (L.L.)
| | - Catherine Sarazin
- Unité de Génie Enzymatique et Cellulaire, UMR 7025 CNRS/UPJV/UTC, Université de Picardie Jules Verne, 80039 Amiens, France; (C.B.); (N.R.-M.); (C.S.)
| | - Sébastien Buchoux
- Unité de Génie Enzymatique et Cellulaire, UMR 7025 CNRS/UPJV/UTC, Université de Picardie Jules Verne, 80039 Amiens, France; (C.B.); (N.R.-M.); (C.S.)
- Correspondence: ; Tel.: +33-(0)3-2282-7473
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4
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Jaipuria G, Ukmar-Godec T, Zweckstetter M. Challenges and approaches to understand cholesterol-binding impact on membrane protein function: an NMR view. Cell Mol Life Sci 2018; 75:2137-2151. [PMID: 29520423 PMCID: PMC11105689 DOI: 10.1007/s00018-018-2789-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Revised: 02/16/2018] [Accepted: 02/27/2018] [Indexed: 01/27/2023]
Abstract
Experimental evidence for a direct role of lipids in determining the structure, dynamics, and function of membrane proteins leads to the term 'functional lipids'. In particular, the sterol molecule cholesterol modulates the activity of many membrane proteins. The precise nature of cholesterol-binding sites and the consequences of modulation of local membrane micro-viscosity by cholesterol, however, is often unknown. Here, we review the current knowledge of the interaction of cholesterol with transmembrane proteins, with a special focus on structural aspects of the interaction derived from nuclear magnetic resonance approaches. We highlight examples of the importance of cholesterol modulation of membrane protein function, discuss the specificity of cholesterol binding, and review the proposed binding motifs from a molecular perspective. We conclude with a short perspective on what could be future trends in research efforts targeted towards a better understanding of cholesterol/membrane protein interactions.
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Affiliation(s)
- Garima Jaipuria
- German Center for Neurodegenerative Diseases (DZNE), Von-Siebold-Str. 3a, 37075, Göttingen, Germany
| | - Tina Ukmar-Godec
- German Center for Neurodegenerative Diseases (DZNE), Von-Siebold-Str. 3a, 37075, Göttingen, Germany
- Department of Neurology, University Medical Center Göttingen, University of Göttingen, Waldweg 33, 37073, Göttingen, Germany
| | - Markus Zweckstetter
- German Center for Neurodegenerative Diseases (DZNE), Von-Siebold-Str. 3a, 37075, Göttingen, Germany.
- Department of Neurology, University Medical Center Göttingen, University of Göttingen, Waldweg 33, 37073, Göttingen, Germany.
- Department for NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany.
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5
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Braun AR, Lacy MM, Ducas VC, Rhoades E, Sachs JN. α-Synuclein's Uniquely Long Amphipathic Helix Enhances its Membrane Binding and Remodeling Capacity. J Membr Biol 2017; 250:183-193. [PMID: 28239748 DOI: 10.1007/s00232-017-9946-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Accepted: 01/24/2017] [Indexed: 10/20/2022]
Abstract
α-Synuclein is the primary protein found in Lewy bodies, the protein and lipid aggregates associated with Parkinson's disease and Lewy body dementia. The protein folds into a uniquely long amphipathic α-helix (AH) when bound to a membrane, and at high enough concentrations, it induces large-scale remodeling of membranes (tubulation and vesiculation). By engineering a less hydrophobic variant of α-Synuclein, we previously showed that the energy associated with binding of α-Synuclein's AH correlates with the extent of membrane remodeling (Braun et al. in J Am Chem Soc 136:9962-9972, 2014). In this study, we combine fluorescence correlation spectroscopy, electron microscopy, and vesicle clearance assays with coarse-grained molecular dynamics simulations to test the impact of decreasing the length of the amphipathic helix on membrane binding energy and tubulation. We show that truncation of α-Synuclein's AH length by approximately 15% reduces both its membrane binding affinity (by fivefold) and membrane remodeling capacity (by nearly 50% on per mole of bound protein basis). Results from simulations correlate well with the experiments and lend support to the idea that at high protein density there is a stabilization of individual, protein-induced membrane curvature fields. The extent to which these curvature fields are stabilized, a function of binding energy, dictates the extent of tubulation. Somewhat surprisingly, we find that this stabilization does not correlate directly with the geometric distribution of the proteins on the membrane surface.
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Affiliation(s)
- Anthony R Braun
- Department of Neuroscience, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Michael M Lacy
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, 06520, USA
| | - Vanessa C Ducas
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, 06520, USA
| | - Elizabeth Rhoades
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, 06520, USA
| | - Jonathan N Sachs
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN, 55455, USA.
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6
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Audagnotto M, Lemmin T, Barducci A, Dal Peraro M. Effect of the Synaptic Plasma Membrane on the Stability of the Amyloid Precursor Protein Homodimer. J Phys Chem Lett 2016; 7:3572-3578. [PMID: 27518597 DOI: 10.1021/acs.jpclett.6b01721] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The proteolytic cleavage of the transmembrane (TM) domain of the amyloid precursor protein (APP) releases amyloid-β (Aβ) peptides, which accumulation in the brain tissue is an early indicator of Alzheimer's disease. We used multiscale molecular dynamics simulations to investigate the stability of APP-TM dimer in realistic models of the synaptic plasma membrane (SPM). Between the two possible dimerization motifs proposed by NMR and EPR, namely G709XXXA713 and G700XXXG704XXXG708, our study revealed that the dimer promoted by the G709XXXA713 motif is not stable in the SPM due to the competition with highly unsaturated lipids that constitute the SPM. Under the same conditions, the dimer promoted by the G700XXXG704XXXG708 motif is instead the most stable species and likely the most biologically relevant. Independently of the dimerization state, both these motifs can be involved in the recruitment of cholesterol molecules.
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Affiliation(s)
- Martina Audagnotto
- Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL) , Lausanne 1015, Switzerland
- Swiss Institute of Bioinformatics (SIB) , Lausanne 1015, Switzerland
| | - Thomas Lemmin
- Department of Pharmaceutical Chemistry, University of California-San Francisco , San Francisco, California 94143, United States
| | - Alessandro Barducci
- Inserm, U1054 Montpellier, France
- Université de Montpellier, CNRS, UMR 5048 , Centre de Biochimie Structurale, U1054 Montpellier, France
| | - Matteo Dal Peraro
- Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL) , Lausanne 1015, Switzerland
- Swiss Institute of Bioinformatics (SIB) , Lausanne 1015, Switzerland
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7
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Fantini J, Di Scala C, Baier CJ, Barrantes FJ. Molecular mechanisms of protein-cholesterol interactions in plasma membranes: Functional distinction between topological (tilted) and consensus (CARC/CRAC) domains. Chem Phys Lipids 2016; 199:52-60. [DOI: 10.1016/j.chemphyslip.2016.02.009] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Revised: 02/24/2016] [Accepted: 02/26/2016] [Indexed: 12/22/2022]
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8
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Common molecular mechanism of amyloid pore formation by Alzheimer's β-amyloid peptide and α-synuclein. Sci Rep 2016; 6:28781. [PMID: 27352802 PMCID: PMC4926208 DOI: 10.1038/srep28781] [Citation(s) in RCA: 125] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 06/08/2016] [Indexed: 12/16/2022] Open
Abstract
Calcium-permeable pores formed by small oligomers of amyloid proteins are the primary pathologic species in Alzheimer’s and Parkinson’s diseases. However, the molecular mechanisms underlying the assembly of these toxic oligomers in the plasma membrane of brain cells remain unclear. Here we have analyzed and compared the pore-forming capability of a large panel of amyloid proteins including wild-type, variant and truncated forms, as well as synthetic peptides derived from specific domains of Aβ1-42 and α-synuclein. We show that amyloid pore formation involves two membrane lipids, ganglioside and cholesterol, that physically interact with amyloid proteins through specific structural motifs. Mutation or deletion of these motifs abolished pore formation. Moreover, α-synuclein (Parkinson) and Aβ peptide (Alzheimer) did no longer form Ca2+-permeable pores in presence of drugs that target either cholesterol or ganglioside or both membrane lipids. These results indicate that gangliosides and cholesterol cooperate to favor the formation of amyloid pores through a common molecular mechanism that can be jammed at two different steps, suggesting the possibility of a universal therapeutic approach for neurodegenerative diseases. Finally we present the first successful evaluation of such a new therapeutic approach (coined “membrane therapy”) targeting amyloid pores formed by Aβ1-42 and α-synuclein.
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9
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Di Scala C, Yahi N, Flores A, Boutemeur S, Kourdougli N, Chahinian H, Fantini J. Broad neutralization of calcium-permeable amyloid pore channels with a chimeric Alzheimer/Parkinson peptide targeting brain gangliosides. Biochim Biophys Acta Mol Basis Dis 2016; 1862:213-22. [DOI: 10.1016/j.bbadis.2015.11.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Revised: 10/27/2015] [Accepted: 11/30/2015] [Indexed: 12/13/2022]
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10
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Posada IMD, Fantini J, Contreras FX, Barrantes F, Alonso A, Goñi FM. A cholesterol recognition motif in human phospholipid scramblase 1. Biophys J 2015; 107:1383-92. [PMID: 25229146 DOI: 10.1016/j.bpj.2014.07.039] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Revised: 06/28/2014] [Accepted: 07/22/2014] [Indexed: 11/26/2022] Open
Abstract
Human phospholipid scramblase 1 (SCR) catalyzes phospholipid transmembrane (flip-flop) motion. This protein is assumed to bind the membrane hydrophobic core through a transmembrane domain (TMD) as well as via covalently bound palmitoyl residues. Here, we explore the possible interaction of the SCR TMD with cholesterol by using a variety of experimental and computational biophysical approaches. Our findings indicate that SCR contains an amino acid segment at the C-terminal region that shows a remarkable affinity for cholesterol, although it lacks the CRAC sequence. Other 3-OH sterols, but not steroids lacking the 3-OH group, also bind this region of the protein. The newly identified cholesterol-binding region is located partly at the C-terminal portion of the TMD and partly in the first amino acid residues in the SCR C-terminal extracellular coil. This finding could be related to the previously described affinity of SCR for cholesterol-rich domains in membranes.
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Affiliation(s)
- Itziar M D Posada
- Unidad de Biofísica (CSIC, UPV/EHU), Departamento de Bioquímica y Biología Molecular, Bilbao, Spain
| | - Jacques Fantini
- Interactions Moléculaires et Systèmes Membranaires, EA-4674, Aix-Marseille Université, Marseille, France
| | - F Xabier Contreras
- Unidad de Biofísica (CSIC, UPV/EHU), Departamento de Bioquímica y Biología Molecular, Bilbao, Spain; IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
| | - Francisco Barrantes
- Laboratory of Molecular Neurobiology, Faculty of Medical Sciences, Biomedical Research Institute (BIOMED) UCA-CONICET, Catholic University of Argentina, Buenos Aires, Argentina
| | - Alicia Alonso
- Unidad de Biofísica (CSIC, UPV/EHU), Departamento de Bioquímica y Biología Molecular, Bilbao, Spain
| | - Félix M Goñi
- Unidad de Biofísica (CSIC, UPV/EHU), Departamento de Bioquímica y Biología Molecular, Bilbao, Spain.
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11
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Deleu M, Crowet JM, Nasir MN, Lins L. Complementary biophysical tools to investigate lipid specificity in the interaction between bioactive molecules and the plasma membrane: A review. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1838:3171-3190. [DOI: 10.1016/j.bbamem.2014.08.023] [Citation(s) in RCA: 102] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Revised: 08/05/2014] [Accepted: 08/21/2014] [Indexed: 02/08/2023]
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12
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Exogenous α-synuclein decreases raft partitioning of Cav2.2 channels inducing dopamine release. J Neurosci 2014; 34:10603-15. [PMID: 25100594 DOI: 10.1523/jneurosci.0608-14.2014] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
α-Synuclein is thought to regulate neurotransmitter release through multiple interactions with presynaptic proteins, cytoskeletal elements, ion channels, and synaptic vesicles membrane. α-Synuclein is abundant in the presynaptic compartment, and its release from neurons and glia has been described as responsible for spreading of α-synuclein-derived pathology. α-Synuclein-dependent dysregulation of neurotransmitter release might occur via its action on surface-exposed calcium channels. Here, we provide electrophysiological and biochemical evidence to show that α-synuclein, applied to rat neurons in culture or striatal slices, selectively activates Cav2.2 channels, and said activation correlates with increased neurotransmitter release. Furthermore, in vivo perfusion of α-synuclein into the striatum also leads to acute dopamine release. We further demonstrate that α-synuclein reduces the amount of plasma membrane cholesterol and alters the partitioning of Cav2.2 channels, which move from raft to cholesterol-poor areas of the plasma membrane. We provide evidence for a novel mechanism through which α-synuclein acts from the extracellular milieu to modulate neurotransmitter release and propose a unifying hypothesis for the mechanism of α-synuclein action on multiple targets: the reorganization of plasma membrane microdomains.
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13
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Bellani S, Mescola A, Ronzitti G, Tsushima H, Tilve S, Canale C, Valtorta F, Chieregatti E. GRP78 clustering at the cell surface of neurons transduces the action of exogenous alpha-synuclein. Cell Death Differ 2014; 21:1971-83. [PMID: 25124556 DOI: 10.1038/cdd.2014.111] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2014] [Revised: 06/02/2014] [Accepted: 07/01/2014] [Indexed: 01/07/2023] Open
Abstract
Mutation or multiplication of the alpha-synuclein (Syn)-encoding gene is frequent cause of early onset Parkinson's disease (PD). Recent evidences point to the pathogenic role of excess Syn also in sporadic PD. Syn is a cytosolic protein, which has been shown to be released from neurons. Here we provide evidence that extracellular Syn induces an increase in surface-exposed glucose-related protein of 78 kDa (GRP78), which becomes clustered in microdomains of the neuronal plasma membrane. Upon interacting with Syn, GRP78 activates a signaling cascade leading to cofilin 1 inactivation and stabilization of microfilaments, thus affecting morphology and dynamics of actin cytoskeleton in cultured neurons. Downregulation of GRP78 abolishes the activity of exogenous Syn, indicating that it is the primary target of Syn. Inactivation of cofilin 1 and stabilization of actin cytoskeleton are present also in fibroblasts derived from genetic PD patients, which show a dramatic increase in stress fibers. Similar changes are displayed by control cells incubated with the medium of PD fibroblasts, only when Syn is present. The accumulation of Syn in the extracellular milieu, its interaction with the plasma membrane and Syn-driven clustering of GRP78 appear, therefore, responsible for the dysregulation of actin turnover, leading to early deficits in synaptic function that precede neurodegeneration.
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Affiliation(s)
- S Bellani
- Division of Neuroscience, San Raffaele Scientific Institute and Vita-Salute University, Milan 20132, Italy
| | - A Mescola
- Department of Nanophysics and Brain Technologies, Istituto Italiano di Tecnologia, Genoa 16163, Italy
| | - G Ronzitti
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, Genoa 16163, Italy
| | - H Tsushima
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, Genoa 16163, Italy
| | - S Tilve
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, Genoa 16163, Italy
| | - C Canale
- Department of Nanophysics and Brain Technologies, Istituto Italiano di Tecnologia, Genoa 16163, Italy
| | - F Valtorta
- Division of Neuroscience, San Raffaele Scientific Institute and Vita-Salute University, Milan 20132, Italy
| | - E Chieregatti
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, Genoa 16163, Italy
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Braun AR, Lacy MM, Ducas VC, Rhoades E, Sachs JN. α-Synuclein-induced membrane remodeling is driven by binding affinity, partition depth, and interleaflet order asymmetry. J Am Chem Soc 2014; 136:9962-72. [PMID: 24960410 PMCID: PMC4105054 DOI: 10.1021/ja5016958] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
We have investigated
the membrane remodeling capacity of the N-terminal
membrane-binding domain of α-synuclein (α-Syn100). Using fluorescence correlation spectroscopy and vesicle clearance
assays, we show that α-Syn100 fully tubulates POPG
vesicles, the first demonstration that the amphipathic helix on its
own is capable of this effect. We also show that at equal density
of membrane-bound protein, α-Syn has dramatically reduced affinity
for, and does not tubulate, vesicles composed of a 1:1 POPG:POPC mixture.
Coarse-grained molecular dynamics simulations suggested that the difference
between the pure POPG and mixture results may be attributed to differences
in the protein’s partition depth, the membrane’s hydrophobic
thickness, and disruption of acyl chain order. To explore the importance
of these attributes compared with the role of the reduced binding
energy, we created an α-Syn100 variant in which we
removed the hydrophobic core of the non-amyloid component (NAC) domain
and tested its impact on pure POPG vesicles. We observed a substantial
reduction in binding affinity and tubulation, and simulations of the
NAC-null protein suggested that the reduced binding energy increases
the protein mobility on the bilayer surface, likely impacting the
protein’s ability to assemble into organized pretubule structures.
We also used simulations to explore a potential role for interleaflet
coupling as an additional driving force for tubulation. We conclude
that symmetry across the leaflets in the tubulated state maximizes
the interaction energy of the two leaflets and relieves the strain
induced by the hydrophobic void beneath the amphipathic helix.
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Affiliation(s)
- Anthony R Braun
- Department of Biomedical Engineering, University of Minnesota , Minneapolis, Minnesota 55455, United States
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Di Scala C, Troadec JD, Lelièvre C, Garmy N, Fantini J, Chahinian H. Mechanism of cholesterol-assisted oligomeric channel formation by a short Alzheimer β-amyloid peptide. J Neurochem 2013; 128:186-95. [PMID: 23919567 DOI: 10.1111/jnc.12390] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Revised: 07/22/2013] [Accepted: 07/31/2013] [Indexed: 11/29/2022]
Abstract
Alzheimer β-amyloid (Aβ) peptides can self-organize into oligomeric ion channels with high neurotoxicity potential. Cholesterol is believed to play a key role in this process, but the molecular mechanisms linking cholesterol and amyloid channel formation have so far remained elusive. Here, we show that the short Aβ22-35 peptide, which encompasses the cholesterol-binding domain of Aβ, induces a specific increase of Ca(2+) levels in neural cells. This effect is neither observed in calcium-free medium nor in cholesterol-depleted cells, and is inhibited by zinc, a blocker of amyloid channel activity. Double mutations V24G/K28G and N27R/K28R in Aβ22-35 modify cholesterol binding and abrogate channel formation. Molecular dynamic simulations suggest that cholesterol induces a tilted α-helical topology of Aβ22-35. This facilitates the establishment of an inter-peptide hydrogen bond network involving Asn-27 and Lys-28, a key step in the octamerization of Aβ22-35 which proceeds gradually until the formation of a perfect annular channel in a phosphatidylcholine membrane. Overall, these data give mechanistic insights into the role of cholesterol in amyloid channel formation, opening up new therapeutic options for Alzheimer's disease. Aβ22-35 peptide, which encompasses the cholesterol binding domain of Aβ, induces a specific increase of Ca(2+) level in neural cells. Double mutations V24G/K28G and N27R/K28R modify cholesterol binding and abrogate channels formation. Molecular dynamic simulations suggest that cholesterol induces a tilted α-helical peptide topology facilitating the formation of annular octameric channels, as schematically shown in the graphic (with a hydrogen bond shown in green for two vicinal peptides). Overall, the data give insights into the role of cholesterol in amyloid channel formation and open up new therapeutic options for Alzheimer's disease.
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Affiliation(s)
- Coralie Di Scala
- Faculté des Sciences, Aix-Marseille Université, EA4674, Marseille, France
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Fantini J, Barrantes FJ. How cholesterol interacts with membrane proteins: an exploration of cholesterol-binding sites including CRAC, CARC, and tilted domains. Front Physiol 2013; 4:31. [PMID: 23450735 PMCID: PMC3584320 DOI: 10.3389/fphys.2013.00031] [Citation(s) in RCA: 326] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Accepted: 02/08/2013] [Indexed: 12/20/2022] Open
Abstract
The plasma membrane of eukaryotic cells contains several types of lipids displaying high biochemical variability in both their apolar moiety (e.g., the acyl chain of glycerolipids) and their polar head (e.g., the sugar structure of glycosphingolipids). Among these lipids, cholesterol is unique because its biochemical variability is almost exclusively restricted to the oxidation of its polar −OH group. Although generally considered the most rigid membrane lipid, cholesterol can adopt a broad range of conformations due to the flexibility of its isooctyl chain linked to the polycyclic sterane backbone. Moreover, cholesterol is an asymmetric molecule displaying a planar α face and a rough β face. Overall, these structural features open up a number of possible interactions between cholesterol and membrane lipids and proteins, consistent with the prominent regulatory functions that this unique lipid exerts on membrane components. The aim of this review is to describe how cholesterol interacts with membrane lipids and proteins at the molecular/atomic scale, with special emphasis on transmembrane domains of proteins containing either the consensus cholesterol-binding motifs CRAC and CARC or a tilted peptide. Despite their broad structural diversity, all these domains bind cholesterol through common molecular mechanisms, leading to the identification of a subset of amino acid residues that are overrepresented in both linear and three-dimensional membrane cholesterol-binding sites.
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Affiliation(s)
- Jacques Fantini
- EA-4674, Interactions Moléculaires et Systèmes Membranaires, Aix-Marseille Université Marseille, France
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Fantini J, Yahi N. The driving force of alpha-synuclein insertion and amyloid channel formation in the plasma membrane of neural cells: key role of ganglioside- and cholesterol-binding domains. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 991:15-26. [PMID: 23775688 DOI: 10.1007/978-94-007-6331-9_2] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Alpha-synuclein is an amyloidogenic protein expressed in brain and involved in Parkinson's disease. It is an intrinsically disordered protein that folds into an alpha-helix rich structure upon binding to membrane lipids. Helical alpha-synuclein can penetrate the membrane and form oligomeric ion channels, thereby eliciting important perturbations of calcium fluxes. The study of alpha-synuclein/lipid interactions had shed some light on the molecular mechanisms controlling the targeting and functional insertion of alpha-synuclein in neural membranes. The protein first interacts with a cell surface glycosphingolipid (ganglioside GM3 in astrocytes or GM1 in neurons). This induces the folding of an alpha-helical domain containing a tilted peptide (67-78) that displays a high affinity for cholesterol. The driving force of the insertion process is the formation of a transient OH-Pi hydrogen bond between the ganglioside and the aromatic ring of the alpha-synuclein residue Tyr-39. The higher polarity of Tyr-39 vs. the lipid bilayer forces the protein to cross the membrane, allowing the tilted peptide to reach cholesterol. The tilted geometry of the cholesterol/alpha-synuclein complex facilitates the formation of an oligomeric channel. Interestingly, this functional cooperation between glycosphingolipids and cholesterol presents a striking analogy with virus fusion mechanisms.
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Affiliation(s)
- Jacques Fantini
- Faculté des Sciences Saint-Jérôme, Aix Marseille University, Marseille, France.
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Morriss-Andrews A, Shea JE. Kinetic pathways to peptide aggregation on surfaces: the effects of β-sheet propensity and surface attraction. J Chem Phys 2012; 136:065103. [PMID: 22360223 DOI: 10.1063/1.3682986] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Mechanisms of peptide aggregation on hydrophobic surfaces are explored using molecular dynamics simulations with a coarse-grained peptide representation. Systems of peptides are studied with varying degrees of backbone rigidity (a measure of β-sheet propensity) and degrees of attraction between their hydrophobic residues and the surface. Multiple pathways for aggregation are observed, depending on the surface attraction and peptide β-sheet propensity. For the case of a single-layered β-sheet fibril forming on the surface (a dominant structure seen in all simulations), three mechanisms are observed: (a) a condensation-ordering transition where a bulk-formed amorphous aggregate binds to the surface and subsequently rearranges to form a fibril; (b) the initial formation of a single-layered fibril in the bulk depositing flat on the surface; and (c) peptides binding individually to the surface and nucleating fibril formation by individual peptide deposition. Peptides with a stiffer chiral backbone prefer mechanism (b) over (a), and stronger surface attractions prefer mechanism (c) over (a) and (b). Our model is compared to various similar experimental systems, and an agreement was found in terms of the surface increasing the degree of fibrillar aggregation, with the directions of fibrillar growth matching the crystallographic symmetry of the surface. Our simulations provide details of aggregate growth mechanisms on scales inaccessible to either experiment or atomistic simulations.
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Affiliation(s)
- Alex Morriss-Andrews
- Department of Physics, University of California Santa Barbara, Santa Barbara, California 93106, USA
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Fantini J, Carlus D, Yahi N. The fusogenic tilted peptide (67-78) of α-synuclein is a cholesterol binding domain. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1808:2343-51. [PMID: 21756873 DOI: 10.1016/j.bbamem.2011.06.017] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2011] [Revised: 06/21/2011] [Accepted: 06/23/2011] [Indexed: 01/06/2023]
Abstract
Parkinson's disease-associated α-synuclein is an amyloidogenic protein not only expressed in the cytoplasm of neurons, but also secreted in the extracellular space and internalized into glial cells through a lipid raft-dependent process. We previously showed that α-synuclein interacts with raft glycosphingolipids through a structural motif common to various viral and amyloidogenic proteins. Here we report that α-synuclein also interacts with cholesterol, as assessed by surface pressure measurements of cholesterol-containing monolayers. Using a panel of recombinant fragments and synthetic peptides, we identified two distinct cholesterol-binding domains in α-synuclein. One of these domains, which corresponds to the tilted peptide of α-synuclein (67-78), bound cholesterol with high affinity and was toxic for cultured astrocytes. Molecular modeling suggested that cholesterol binds to this peptide with a tilt angle of 46°. α-synuclein also contains a cholesterol recognition consensus motif, which had a lower affinity for cholesterol and was devoid of toxicity. This motif is encased in the glycosphingolipid-binding domain (34-45) of α-synuclein. In raft-like model membranes containing both cholesterol and glycosphingolipids, the head groups of glycosphingolipids prevented the accessibility of cholesterol to exogenous ligands. Nevertheless, cholesterol appeared to 'signal' its presence by tuning glycosphingolipid conformation, thereby facilitating α-synuclein binding to raft-like membranes. We propose that the association of α-synuclein with lipid rafts involves both the binding of α-synuclein (34-45) to glycosphingolipids, and the interaction of the fusogenic tilted peptide (67-78) with cholesterol. Coincidentally, a similar mechanism is used by viruses (HIV-1, HTLV-I, Ebola) which display a tilted peptide and fuse with host cell membranes through a sphingolipid/cholesterol-dependent process.
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Nikolic A, Baud S, Rauscher S, Pomès R. Molecular mechanism of β-sheet self-organization at water-hydrophobic interfaces. Proteins 2010; 79:1-22. [DOI: 10.1002/prot.22854] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2010] [Revised: 07/21/2010] [Accepted: 07/24/2010] [Indexed: 12/20/2022]
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21
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Abdulreda MH, Moy VT. Investigation of SNARE-Mediated Membrane Fusion Mechanism Using Atomic Force Microscopy. JAPANESE JOURNAL OF APPLIED PHYSICS (2008) 2009; 48:8JA03-8JA0310. [PMID: 20228892 PMCID: PMC2836841 DOI: 10.1143/jjap.48.08ja03] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Membrane fusion is driven by specialized proteins that reduce the free energy penalty for the fusion process. In neurons and secretory cells, soluble N-ethylmaleimide-sensitive factor-attachment protein (SNAP) receptors (SNAREs) mediate vesicle fusion with the plasma membrane during vesicular content release. Although, SNAREs have been widely accepted as the minimal machinery for membrane fusion, the specific mechanism for SNARE-mediated membrane fusion remains an active area of research. Here, we summarize recent findings based on force measurements acquired in a novel experimental system that uses atomic force microscope (AFM) force spectroscopy to investigate the mechanism(s) of membrane fusion and the role of SNAREs in facilitating membrane hemifusion during SNARE-mediated fusion. In this system, protein-free and SNARE-reconstituted lipid bilayers are formed on opposite (trans) substrates and the forces required to induce membrane hemifusion and fusion or to unbind single v-/t-SNARE complexes are measured. The obtained results provide evidence for a mechanism by which the pulling force generated by interacting trans-SNAREs provides critical proximity between the membranes and destabilizes the bilayers at fusion sites by broadening the hemifusion energy barrier and consequently making the membranes more prone to fusion.
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Madine J, Hughes E, Doig AJ, Middleton DA. The effects of α-synuclein on phospholipid vesicle integrity: a study using31P NMR and electron microscopy. Mol Membr Biol 2009; 25:518-27. [DOI: 10.1080/09687680802467977] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Abdulreda MH, Bhalla A, Rico F, Berggren PO, Chapman ER, Moy VT. Pulling force generated by interacting SNAREs facilitates membrane hemifusion. Integr Biol (Camb) 2009; 1:301-10. [PMID: 20023730 DOI: 10.1039/b900685k] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In biological systems, membrane fusion is mediated by specialized proteins. Although soluble N-ethylmaleimide-sensitive factor attachment protein (SNAP) receptors (SNAREs) provide the minimal molecular machinery required to drive membrane fusion, the precise mechanism for SNARE-mediated fusion remains to be established. Here, we used atomic force microscope (AFM) spectroscopy to determine whether the pulling force generated by interacting SNAREs is directly coupled to membrane fusion. The mechanical strength of the SNARE binding interaction was determined by single molecule force measurements. It was revealed that the forced unbinding of the SNARE complex formed between opposing (trans) bilayers involves two activation barriers; where the steep inner barrier governs the transition from the bound to an intermediate state and the outer barrier governs the transition between the intermediate and the unbound state. Moreover, truncation of either SNAP-25 or VAMP 2 reduced the slope of the inner barrier significantly and, consequently, reduced the pulling strength of the SNARE complex; thus, suggesting that the inner barrier determines the binding strength of the SNARE complex. In parallel, AFM compression force measurements revealed that truncated SNAREs were less efficient than native SNAREs in facilitating hemifusion of the apposed bilayers. Together, these findings reveal a mechanism by which a pulling force generated by interacting trans-SNAREs reduces the slope of the hemifusion barrier and, subsequently, facilitates hemifusion and makes the membranes more prone to fusion.
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Affiliation(s)
- Midhat H Abdulreda
- University of Miami Miller School of Medicine, Physiology & Biophysics Department, 1600 NW 10th Ave., Miami, FL 33136, USA
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Relationships between the orientation and the structural properties of peptides and their membrane interactions. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2008; 1778:1537-44. [DOI: 10.1016/j.bbamem.2008.04.006] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2007] [Revised: 04/14/2008] [Accepted: 04/21/2008] [Indexed: 11/17/2022]
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