1
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Galvagnion C, Barclay A, Makasewicz K, Marlet FR, Moulin M, Devos JM, Linse S, Martel A, Porcar L, Sparr E, Pedersen MC, Roosen-Runge F, Arleth L, Buell AK. Structural characterisation of α-synuclein-membrane interactions and the resulting aggregation using small angle scattering. Phys Chem Chem Phys 2024; 26:10998-11013. [PMID: 38526443 DOI: 10.1039/d3cp05928f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/26/2024]
Abstract
The presence of amyloid fibrils is a hallmark of several neurodegenerative diseases. Some amyloidogenic proteins, such as α-synuclein and amyloid β, interact with lipids, and this interaction can strongly favour the formation of amyloid fibrils. In particular the primary nucleation step, i.e. the de novo formation of amyloid fibrils, has been shown to be accelerated by lipids. However, the exact mechanism of this acceleration is still mostly unclear. Here we use a range of scattering methods, such as dynamic light scattering (DLS) and small angle X-ray and neutron scattering (SAXS and SANS) to obtain structural information on the binding of α-synuclein to model membranes formed from negatively charged lipids and their co-assembly into amyloid fibrils. We find that the model membranes take an active role in the reaction. The binding of α synuclein to the model membranes immediately induces a major structural change in the lipid assembly, which leads to a break-up into small and mostly disc- or rod-like lipid-protein particles. This transition can be reversed by temperature changes or proteolytic protein removal. Incubation of the small lipid-α-synuclein particles for several hours, however, leads to amyloid fibril formation, whereby the lipids are incorporated into the amyloid fibrils.
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Affiliation(s)
- Céline Galvagnion
- Department of Drug Design and Pharmacology, University of Copenhagen, 2100 Copenhagen, Denmark.
| | - Abigail Barclay
- Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Katarzyna Makasewicz
- Division of Physical Chemistry, Center for Chemistry and Chemical Engineering, Lund University, P.O. Box 124, SE-22100, Lund, Sweden
| | | | - Martine Moulin
- Institut Laue-Langevin, 71 avenue des Martyrs, 38042 Grenoble, France
| | - Juliette M Devos
- Institut Laue-Langevin, 71 avenue des Martyrs, 38042 Grenoble, France
| | - Sara Linse
- Department of Biochemistry and Structural Biology, Lund University, SE22100 Lund, Sweden
| | - Anne Martel
- Institut Laue-Langevin, 71 avenue des Martyrs, 38042 Grenoble, France
| | - Lionel Porcar
- Institut Laue-Langevin, 71 avenue des Martyrs, 38042 Grenoble, France
| | - Emma Sparr
- Division of Physical Chemistry, Center for Chemistry and Chemical Engineering, Lund University, P.O. Box 124, SE-22100, Lund, Sweden
| | | | - Felix Roosen-Runge
- Division of Physical Chemistry, Center for Chemistry and Chemical Engineering, Lund University, P.O. Box 124, SE-22100, Lund, Sweden
- Department of Biomedical Sciences and Biofilms Research Center for Biointerfaces, Malmö University, Malmö, Sweden
| | - Lise Arleth
- Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Alexander K Buell
- Department of Biotechnology and Biomedicine, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark.
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Chia S, Cataldi RL, Ruggeri FS, Limbocker R, Condado-Morales I, Pisani K, Possenti A, Linse S, Knowles TPJ, Habchi J, Mannini B, Vendruscolo M. A Relationship between the Structures and Neurotoxic Effects of Aβ Oligomers Stabilized by Different Metal Ions. ACS Chem Neurosci 2024; 15:1125-1134. [PMID: 38416693 PMCID: PMC10958495 DOI: 10.1021/acschemneuro.3c00718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2023] [Revised: 02/06/2024] [Accepted: 02/06/2024] [Indexed: 03/01/2024] Open
Abstract
Oligomeric assemblies of the amyloid β peptide (Aβ) have been investigated for over two decades as possible neurotoxic agents in Alzheimer's disease. However, due to their heterogeneous and transient nature, it is not yet fully established which of the structural features of these oligomers may generate cellular damage. Here, we study distinct oligomer species formed by Aβ40 (the 40-residue form of Aβ) in the presence of four different metal ions (Al3+, Cu2+, Fe2+, and Zn2+) and show that they differ in their structure and toxicity in human neuroblastoma cells. We then describe a correlation between the size of the oligomers and their neurotoxic activity, which provides a type of structure-toxicity relationship for these Aβ40 oligomer species. These results provide insight into the possible role of metal ions in Alzheimer's disease by the stabilization of Aβ oligomers.
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Affiliation(s)
- Sean Chia
- Centre
for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, U.K.
| | - Rodrigo Lessa Cataldi
- Centre
for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, U.K.
| | - Francesco Simone Ruggeri
- Centre
for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, U.K.
| | - Ryan Limbocker
- Centre
for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, U.K.
| | - Itzel Condado-Morales
- Centre
for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, U.K.
| | - Katarina Pisani
- Centre
for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, U.K.
| | - Andrea Possenti
- Centre
for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, U.K.
| | - Sara Linse
- Department
of Biochemistry & Structural Biology, Center for Molecular Protein
Science, Lund University, PO box 124, 221 00 Lund, Sweden
| | - Tuomas P. J. Knowles
- Centre
for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, U.K.
- Department
of Physics, Cavendish Laboratory, Cambridge CB3 0HE, U.K.
| | - Johnny Habchi
- Centre
for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, U.K.
| | - Benedetta Mannini
- Centre
for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, U.K.
| | - Michele Vendruscolo
- Centre
for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, U.K.
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3
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Dai L, Wang J, Zhang X, Yan M, Zhou L, Zhang G, Meng L, Chen L, Cao X, Zhang Z, Wang G, Zhang Z. 27-Hydroxycholesterol Drives the Spread of α-Synuclein Pathology in Parkinson's Disease. Mov Disord 2023; 38:2005-2018. [PMID: 37593929 DOI: 10.1002/mds.29577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2023] [Accepted: 07/28/2023] [Indexed: 08/19/2023] Open
Abstract
BACKGROUND The accumulation and aggregation of α-synuclein (α-Syn) are characteristic of Parkinson's disease (PD). Epidemiological evidence indicates that hyperlipidemia is associated with an increased risk of PD. The levels of 27-hydroxycholesterol (27-OHC), a cholesterol oxidation derivative, are increased in the brain and cerebrospinal fluid of patients with PD. However, whether 27-OHC plays a role in α-Syn aggregation and propagation remains elusive. OBJECTIVE The aim of this study was to determine whether 27-OHC regulates α-Syn aggregation and propagation. METHODS Purified recombinant α-Syn, neuronal cultures, and α-Syn fibril-injected mouse model of PD were treated with 27-OHC. In addition, CYP27A1 knockout mice were used to investigate the effect of lowering 27-OHC on α-Syn pathology in vivo. RESULTS 27-OHC accelerates the aggregation of α-Syn and enhances the seeding activity of α-Syn fibrils. Furthermore, the 27-OHC-modified α-Syn fibrils localize to the mitochondria and induce mitochondrial dysfunction and neurotoxicity. Injection of 27-OHC-modified α-Syn fibrils induces enhanced spread of α-Syn pathology and dopaminergic neurodegeneration compared with pure α-Syn fibrils. Similarly, subcutaneous administration of 27-OHC facilitates the seeding of α-Syn pathology. Genetic deletion of cytochrome P450 27A1 (CYP27A1), the enzyme that converts cholesterol to 27-OHC, ameliorates the spread of pathologic α-Syn, degeneration of the nigrostriatal dopaminergic pathway, and motor impairments. These results indicate that the cholesterol metabolite 27-OHC plays an important role in the pathogenesis of PD. CONCLUSIONS 27-OHC promotes the aggregation and spread of α-Syn. Strategies aimed at inhibiting the CYP27A1-27-OHC axis may hold promise as a disease-modifying therapy to halt the progression of α-Syn pathology in PD. © 2023 International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Lijun Dai
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Jiannan Wang
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Xingyu Zhang
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Mingmin Yan
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Lingyan Zhou
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Guoxin Zhang
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Lanxia Meng
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Liam Chen
- Department of Laboratory Medicine and Pathology, University of Minnesota Medical School, Minneapolis, Minnesota, USA
| | - Xuebing Cao
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Zhaohui Zhang
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Gaohua Wang
- Department of Psychiatry, Renmin Hospital of Wuhan University, Wuhan, China
| | - Zhentao Zhang
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, China
- TaiKang Center for Life and Medical Sciences, Wuhan University, Wuhan, China
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The Consequences of GBA Deficiency in the Autophagy-Lysosome System in Parkinson's Disease Associated with GBA. Cells 2023; 12:cells12010191. [PMID: 36611984 PMCID: PMC9818455 DOI: 10.3390/cells12010191] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 12/27/2022] [Accepted: 12/31/2022] [Indexed: 01/05/2023] Open
Abstract
GBA gene variants were the first genetic risk factor for Parkinson's disease. GBA encodes the lysosomal enzyme glucocerebrosidase (GBA), which is involved in sphingolipid metabolism. GBA exhibits a complex physiological function that includes not only the degradation of its substrate glucosylceramide but also the metabolism of other sphingolipids and additional lipids such as cholesterol, particularly when glucocerebrosidase activity is deficient. In the context of Parkinson's disease associated with GBA, the loss of GBA activity has been associated with the accumulation of α-synuclein species. In recent years, several hypotheses have proposed alternative and complementary pathological mechanisms to explain why lysosomal enzyme mutations lead to α-synuclein accumulation and become important risk factors in Parkinson's disease etiology. Classically, loss of GBA activity has been linked to a dysfunctional autophagy-lysosome system and to a subsequent decrease in autophagy-dependent α-synuclein turnover; however, several other pathological mechanisms underlying GBA-associated parkinsonism have been proposed. This review summarizes and discusses the different hypotheses with a special focus on autophagy-dependent mechanisms, as well as autophagy-independent mechanisms, where the role of other players such as sphingolipids, cholesterol and other GBA-related proteins make important contributions to Parkinson's disease pathogenesis.
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5
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Kozlov MM, Taraska JW. Generation of nanoscopic membrane curvature for membrane trafficking. Nat Rev Mol Cell Biol 2023; 24:63-78. [PMID: 35918535 DOI: 10.1038/s41580-022-00511-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/20/2022] [Indexed: 11/09/2022]
Abstract
Curved membranes are key features of intracellular organelles, and their generation involves dynamic protein complexes. Here we describe the fundamental mechanisms such as the hydrophobic insertion, scaffolding and crowding mechanisms these proteins use to produce membrane curvatures and complex shapes required to form intracellular organelles and vesicular structures involved in endocytosis and secretion. For each mechanism, we discuss its cellular functions as well as the underlying physical principles and the specific membrane properties required for the mechanism to be feasible. We propose that the integration of individual mechanisms into a highly controlled, robust process of curvature generation often relies on the assembly of proteins into coats. How cells unify and organize the curvature-generating factors at the nanoscale is presented for three ubiquitous coats central for membrane trafficking in eukaryotes: clathrin-coated pits, caveolae, and COPI and COPII coats. The emerging theme is that these coats arrange and coordinate curvature-generating factors in time and space to dynamically shape membranes to accomplish membrane trafficking within cells.
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Affiliation(s)
- Michael M Kozlov
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
| | - Justin W Taraska
- Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA.
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6
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Vieira N, Rito T, Correia-Neves M, Sousa N. Sorting Out Sorting Nexins Functions in the Nervous System in Health and Disease. Mol Neurobiol 2021; 58:4070-4106. [PMID: 33931804 PMCID: PMC8280035 DOI: 10.1007/s12035-021-02388-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 04/05/2021] [Indexed: 12/18/2022]
Abstract
Endocytosis is a fundamental process that controls protein/lipid composition of the plasma membrane, thereby shaping cellular metabolism, sensing, adhesion, signaling, and nutrient uptake. Endocytosis is essential for the cell to adapt to its surrounding environment, and a tight regulation of the endocytic mechanisms is required to maintain cell function and survival. This is particularly significant in the central nervous system (CNS), where composition of neuronal cell surface is crucial for synaptic functioning. In fact, distinct pathologies of the CNS are tightly linked to abnormal endolysosomal function, and several genome wide association analysis (GWAS) and biochemical studies have identified intracellular trafficking regulators as genetic risk factors for such pathologies. The sorting nexins (SNXs) are a family of proteins involved in protein trafficking regulation and signaling. SNXs dysregulation occurs in patients with Alzheimer’s disease (AD), Down’s syndrome (DS), schizophrenia, ataxia and epilepsy, among others, establishing clear roles for this protein family in pathology. Interestingly, restoration of SNXs levels has been shown to trigger synaptic plasticity recovery in a DS mouse model. This review encompasses an historical and evolutionary overview of SNXs protein family, focusing on its organization, phyla conservation, and evolution throughout the development of the nervous system during speciation. We will also survey SNXs molecular interactions and highlight how defects on SNXs underlie distinct pathologies of the CNS. Ultimately, we discuss possible strategies of intervention, surveying how our knowledge about the fundamental processes regulated by SNXs can be applied to the identification of novel therapeutic avenues for SNXs-related disorders.
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Affiliation(s)
- Neide Vieira
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus Gualtar, 4710-057, Braga, Portugal. .,ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal.
| | - Teresa Rito
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus Gualtar, 4710-057, Braga, Portugal.,ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Margarida Correia-Neves
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus Gualtar, 4710-057, Braga, Portugal.,ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Nuno Sousa
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus Gualtar, 4710-057, Braga, Portugal.,ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
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7
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Wang N, Clark LD, Gao Y, Kozlov MM, Shemesh T, Rapoport TA. Mechanism of membrane-curvature generation by ER-tubule shaping proteins. Nat Commun 2021; 12:568. [PMID: 33495454 PMCID: PMC7835363 DOI: 10.1038/s41467-020-20625-y] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Accepted: 12/07/2020] [Indexed: 12/15/2022] Open
Abstract
The endoplasmic reticulum (ER) network consists of tubules with high membrane curvature in cross-section, generated by the reticulons and REEPs. These proteins have two pairs of trans-membrane (TM) segments, followed by an amphipathic helix (APH), but how they induce curvature is poorly understood. Here, we show that REEPs form homodimers by interaction within the membrane. When overexpressed or reconstituted at high concentrations with phospholipids, REEPs cause extreme curvature through their TMs, generating lipoprotein particles instead of vesicles. The APH facilitates curvature generation, as its mutation prevents ER network formation of reconstituted proteoliposomes, and synthetic L- or D-amino acid peptides abolish ER network formation in Xenopus egg extracts. In Schizosaccharomyces japonicus, the APH is required for reticulon’s exclusive ER-tubule localization and restricted mobility. Thus, the TMs and APH cooperate to generate high membrane curvature. We propose that the formation of splayed REEP/reticulon dimers is responsible for ER tubule formation. The endoplasmic reticulum network consists of tubules with high membrane curvature in cross-section, generated by the reticulons and REEPs, but how they introduce curvature is poorly understood. Here authors show that REEPs form homodimers and use their amphipathic helix and trans-membrane segments to introduce high membrane curvature that can even lead to the formation of lipoprotein particles.
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Affiliation(s)
- Ning Wang
- Howard Hughes Medical Institute and Department of Cell Biology, Harvard Medical School, Boston, MA, 02115, USA
| | - Lindsay D Clark
- Howard Hughes Medical Institute and Department of Cell Biology, Harvard Medical School, Boston, MA, 02115, USA
| | - Yuan Gao
- Howard Hughes Medical Institute and Department of Cell Biology, Harvard Medical School, Boston, MA, 02115, USA
| | - Michael M Kozlov
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, 69978, Israel
| | - Tom Shemesh
- Faculty of Biology, Technion-Israel Institute of Technology, Haifa, 32000, Israel
| | - Tom A Rapoport
- Howard Hughes Medical Institute and Department of Cell Biology, Harvard Medical School, Boston, MA, 02115, USA.
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8
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Abstract
α-Synuclein (α-syn) is a key protein in the etiology of Parkinson's disease. In a disease state, α-syn accumulates as insoluble amyloid fibrils enriched in β-sheet structure. However, in its functional state, α-syn adopts an amphipathic helix upon membrane association and plays a role in synaptic vesicle docking, fusion, and clustering. In this Account, we describe our contributions made in the past decade toward developing a molecular understanding of α-syn membrane interactions, which are crucial for function and have pathological implications. Three topics are covered: α-syn membrane binding probed by neutron reflectometry (NR), the effects of membrane on α-syn amyloid formation, and interactions of α-syn with cellular membranes.NR offers a unique perspective by providing direct measurements of protein penetration depth. By the use of segmentally deuterated α-syn generated through native chemical ligation, the spatial resolution of specific membrane-bound polypeptide regions was determined by NR. Additionally, we used NR to characterize the membrane-bound complex of α-syn and glucocerebrosidase, a lysosomal hydrolase whose mutations are a common genetic risk factor for Parkinson's disease. Although phosphatidylcholine (PC) is the most abundant lipid species in mammalian cells, interactions of PC with α-syn have been largely ignored because they are substantially weaker compared with the electrostatically driven binding of negatively charged lipids. We discovered that α-syn tubulates zwitterionic PC membranes, which is likely related to its involvement in synaptic vesicle fusion by stabilization of membrane curvature. Interestingly, PC lipid tubules inhibit amyloid formation, in contrast to anionic phosphatidylglycerol lipid tubules, which stimulate protein aggregation. We also found that membrane fluidity influences the propensity of α-synuclein amyloid formation. Most recently, we obtained direct evidence of binding of α-syn to exocytic sites on intact cellular membranes using a method called cellular unroofing. This method provides direct access to the cytosolic plasma membrane. Importantly, measurements of fluorescence lifetime distributions revealed that α-syn is more conformationally dynamic at the membrane interface than previously appreciated. This exquisite responsiveness to specific lipid composition and membrane topology is important for both its physiological and pathological functions. Collectively, our work has provided insights into the effects of the chemical nature of phospholipid headgroups on the interplay among membrane remodeling, protein structure, and α-syn amyloid formation.
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Affiliation(s)
- Upneet Kaur
- Laboratory of Protein Conformation and Dynamics, Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Jennifer C. Lee
- Laboratory of Protein Conformation and Dynamics, Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892, United States
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9
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Musteikytė G, Jayaram AK, Xu CK, Vendruscolo M, Krainer G, Knowles TPJ. Interactions of α-synuclein oligomers with lipid membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1863:183536. [PMID: 33373595 DOI: 10.1016/j.bbamem.2020.183536] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 12/10/2020] [Accepted: 12/13/2020] [Indexed: 12/24/2022]
Abstract
Parkinson's disease is an increasingly prevalent and currently incurable neurodegenerative disorder. At the molecular level, this disease is characterized by the formation of aberrant intracellular protein deposits known as Lewy bodies. Oligomeric forms of the protein α-synuclein (αS), which are believed to be both intermediates and by-products of Lewy body formation, are considered to be the main pathogenic species. Interactions of such oligomers with lipid membranes are increasingly emerging as a major molecular pathway underpinning their toxicity. Here we review recent progress in our understanding of the interactions of αS oligomers with lipid membranes. We highlight key structural and biophysical features of αS oligomers, the effects of these features on αS oligomer membrane binding properties, and resultant implications for understanding the etiology of Parkinson's disease. We discuss mechanistic modes of αS oligomer-lipid membrane interactions and the effects of environmental factors to such modes. Finally, we provide an overview of the current understanding of the main molecular determinants of αS oligomer toxicity in vivo.
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Affiliation(s)
- Greta Musteikytė
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Akhila K Jayaram
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom; Cavendish Laboratory, University of Cambridge, J J Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Catherine K Xu
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Michele Vendruscolo
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Georg Krainer
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom.
| | - Tuomas P J Knowles
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom; Cavendish Laboratory, University of Cambridge, J J Thomson Avenue, Cambridge CB3 0HE, United Kingdom.
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Adão R, Cruz PF, Vaz DC, Fonseca F, Pedersen JN, Ferreira-da-Silva F, Brito RM, Ramos CH, Otzen D, Keller S, Bastos M. DIBMA nanodiscs keep α-synuclein folded. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183314. [DOI: 10.1016/j.bbamem.2020.183314] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 04/10/2020] [Accepted: 04/13/2020] [Indexed: 02/08/2023]
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11
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Vane EW, He S, Maibaum L, Nath A. Rapid Formation of Peptide/Lipid Coaggregates by the Amyloidogenic Seminal Peptide PAP 248-286. Biophys J 2020; 119:924-938. [PMID: 32814060 PMCID: PMC7474197 DOI: 10.1016/j.bpj.2020.07.029] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 07/14/2020] [Accepted: 07/29/2020] [Indexed: 12/27/2022] Open
Abstract
Protein/lipid coassembly is an understudied phenomenon that is important to the function of antimicrobial peptides as well as the pathological effects of amyloid. Here, we study the coassembly process of PAP248-286, a seminal peptide that displays both amyloid-forming and antimicrobial activity. PAP248-286 is a peptide fragment of prostatic acid phosphatase and has been reported to form amyloid fibrils, known as semen-derived enhancer of viral infection (SEVI), that enhance the viral infectivity of human immunodeficiency virus. We find that in addition to forming amyloid, PAP248-286 much more readily assembles with lipid vesicles into peptide/lipid coaggregates that resemble amyloid fibrils in some important ways but are a distinct species. The formation of these PAP248-286/lipid coaggregates, which we term "messicles," is controlled by the peptide:lipid (P:L) ratio and by the lipid composition. The optimal P:L ratio is around 1:10, and at least 70% anionic lipid is required for coaggregate formation. Once formed, messicles are not disrupted by subsequent changes in P:L ratio. We propose that messicles form through a polyvalent assembly mechanism, in which a critical surface density of PAP248-286 on liposomes enables peptide-mediated particle bridging into larger species. Even at ∼50-fold lower PAP248-286 concentrations, messicles form at least 10-fold faster than amyloid fibrils. It is therefore possible that some or all of the biological activities assigned to SEVI, the amyloid form of PAP248-286, could instead be attributed to a PAP248-286/lipid coaggregate. More broadly speaking, this work could provide a potential framework for the discovery and characterization of nonamyloid peptide/lipid coaggregates by other amyloid-forming proteins and antimicrobial peptides.
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Affiliation(s)
- Eleanor W Vane
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington; Biological Physics, Structure and Design Program, University of Washington, Seattle, Washington
| | - Shushan He
- Department of Chemistry, University of Washington, Seattle, Washington
| | - Lutz Maibaum
- Department of Chemistry, University of Washington, Seattle, Washington
| | - Abhinav Nath
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington; Biological Physics, Structure and Design Program, University of Washington, Seattle, Washington.
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12
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Abstract
α-Synuclein is a neuronal protein with an ill-defined biological function that is central to Parkinson’s disease etiology. While considered to be involved in exocytosis, how α-synuclein facilitates synaptic vesicle fusion and release remains an open question. To address this, we investigated α-synuclein–lipid interactions at the plasma membrane through the technique of cellular unroofing, which uncovers an intact basal membrane. We conclusively show that α-synuclein is recruited to exocytic sites, preferring liquid-ordered lipid domains. Importantly, heterogeneous populations of α-synuclein conformers are revealed by measurements of fluorescence lifetime distributions, which are not adequately described by current models of α-synuclein structures. Membrane-bound α-synuclein is conformationally dynamic, exquisitely sensitive to lipid/protein composition, enabling the protein to carry out its function. Parkinson’s disease is associated with α-synuclein (α-syn), a cytosolic protein enriched in presynaptic terminals. The biological function of α-syn remains elusive; however, increasing evidence suggests that the protein is involved in the regulation of synaptic vesicle fusion, signifying the importance of α-syn–lipid interactions. We show that α-syn preferentially binds to GM1-rich, liquid-ordered lipid domains on cytoplasmic membranes by using unroofed cells, which encapsulates lipid complexity and cellular topology. Moreover, proteins (Rab3a, syntaxin-1A, and VAMP2) involved in exocytosis also localize with α-syn, supporting its proposed functional role in exocytosis. To investigate how these lipid/protein interactions influence α-syn at the residue level, α-syn was derivatized with an environmentally sensitive fluorophore (7-nitrobenz-2-oxa-1,3-diazol-4-yl [NBD]) at different N- and C-terminal sites. Measurements of NBD fluorescence lifetime distributions reveal that α-syn adopts a multitude of membrane-bound conformations, which were not recapitulated in simple micelle or vesicle models, indicating an exquisite sensitivity of the protein to the complex lipid environment. Interestingly, these data also suggest the participation of the C terminus in membrane localization, which is generally overlooked and thus emphasize the need to use cellularly derived and biologically relevant membranes for biophysical characterization. Collectively, our results demonstrate that α-syn is more conformationally dynamic at the membrane interface than previously appreciated, which may be important for both its physiological and pathological functions.
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13
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Jin U, Park SJ, Park SM. Cholesterol Metabolism in the Brain and Its Association with Parkinson's Disease. Exp Neurobiol 2019; 28:554-567. [PMID: 31698548 PMCID: PMC6844833 DOI: 10.5607/en.2019.28.5.554] [Citation(s) in RCA: 95] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 10/18/2019] [Accepted: 10/21/2019] [Indexed: 12/11/2022] Open
Abstract
Parkinson’s disease (PD) is the second most progressive neurodegenerative disorder of the aging population after Alzheimer’s disease (AD). Defects in the lysosomal systems and mitochondria have been suspected to cause the pathogenesis of PD. Nevertheless, the pathogenesis of PD remains obscure. Abnormal cholesterol metabolism is linked to numerous disorders, including atherosclerosis. The brain contains the highest level of cholesterol in the body and abnormal cholesterol metabolism links also many neurodegenerative disorders such as AD, PD, Huntington’s disease (HD), and amyotrophic lateral sclerosis (ALS). The blood brain barrier effectively prevents uptake of lipoprotein-bound cholesterol from blood circulation. Accordingly, cholesterol level in the brain is independent from that in peripheral tissues. Because cholesterol metabolism in both peripheral tissue and the brain are quite different, cholesterol metabolism associated with neurodegeneration should be examined separately from that in peripheral tissues. Here, we review and compare cholesterol metabolism in the brain and peripheral tissues. Furthermore, the relationship between alterations in cholesterol metabolism and PD pathogenesis is reviewed.
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Affiliation(s)
- Uram Jin
- Department of Pharmacology, Ajou University School of Medicine, Suwon 16499, Korea.,Center for Convergence Research of Neurological Disorders, Ajou University School of Medicine, Suwon 16499, Korea.,Department of Cardiology, Ajou University School of Medicine, Suwon 16499, Korea
| | - Soo Jin Park
- Department of Pharmacology, Ajou University School of Medicine, Suwon 16499, Korea.,Center for Convergence Research of Neurological Disorders, Ajou University School of Medicine, Suwon 16499, Korea.,Department of Thoracic and Cardiovascular Surgery, Ajou University School of Medicine, Suwon 16499, Korea
| | - Sang Myun Park
- Department of Pharmacology, Ajou University School of Medicine, Suwon 16499, Korea.,Center for Convergence Research of Neurological Disorders, Ajou University School of Medicine, Suwon 16499, Korea.,BK21 Plus Program, Department of Biomedical Sciences, Ajou University School of Medicine, Suwon 16499, Korea
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14
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Isacson O, Brekk OR, Hallett PJ. Novel Results and Concepts Emerging From Lipid Cell Biology Relevant to Degenerative Brain Aging and Disease. Front Neurol 2019; 10:1053. [PMID: 31649605 PMCID: PMC6794469 DOI: 10.3389/fneur.2019.01053] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Accepted: 09/17/2019] [Indexed: 01/26/2023] Open
Abstract
While very rare familial forms of proteinopathy can cause Parkinson's disease (PD), Lewy body dementia (LBD) and age-related dementias, recent in-depth studies of lipid disturbances in the majority of the common forms of these diseases instead suggest a primary pathogenesis in lipid pathways. This review synthesizes a perspective from new data that point to an interdependence of lipids and proteinopathy. This article describes disturbed relationships in lipid homeostasis that causes neuropathology to develop over time and with age, which includes altered mechanisms of glia-neuron exchange of lipids and inflammatory signals.
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Affiliation(s)
- Ole Isacson
- McLean Hospital and Harvard Medical School, Neuroregeneration Research Institute, Belmont, MA, United States
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15
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Tao M, Pandey NK, Barnes R, Han S, Langen R. Structure of Membrane-Bound Huntingtin Exon 1 Reveals Membrane Interaction and Aggregation Mechanisms. Structure 2019; 27:1570-1580.e4. [PMID: 31466833 DOI: 10.1016/j.str.2019.08.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 07/23/2019] [Accepted: 08/09/2019] [Indexed: 02/08/2023]
Abstract
Huntington's disease is caused by a polyQ expansion in the first exon of huntingtin (Httex1). Membrane interaction of huntingtin is of physiological and pathological relevance. Using electron paramagnetic resonance and Overhauser dynamic nuclear polarization, we find that the N-terminal residues 3-13 of wild-type Httex1(Q25) form a membrane-bound, amphipathic α helix. This helix is positioned in the interfacial region, where it is sensitive to membrane curvature and electrostatic interactions with head-group charges. Residues 14-22, which contain the first five residues of the polyQ region, are in a transition region that remains in the interfacial region without taking up a stable, α-helical structure. The remaining C-terminal portion is solvent exposed. The phosphomimetic S13D/S16D mutations, which are known to protect from toxicity, inhibit membrane binding and attenuate membrane-mediated aggregation of mutant Httex1(Q46) due to electrostatic repulsion. Targeting the N-terminal membrane anchor using post-translational modifications or specific binders could be a potential means to reduce aggregation and toxicity in vivo.
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Affiliation(s)
- Meixin Tao
- Department of Neuroscience and Physiology, Department of Biochemistry and Molecular Medicine, Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Nitin K Pandey
- Department of Neuroscience and Physiology, Department of Biochemistry and Molecular Medicine, Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Ryan Barnes
- Department of Chemistry and Biochemistry, Department of Chemical Engineering, University of California Santa Barbara, Santa Barbara, CA 93106, USA
| | - Songi Han
- Department of Chemistry and Biochemistry, Department of Chemical Engineering, University of California Santa Barbara, Santa Barbara, CA 93106, USA
| | - Ralf Langen
- Department of Neuroscience and Physiology, Department of Biochemistry and Molecular Medicine, Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA.
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16
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Hallett PJ, Engelender S, Isacson O. Lipid and immune abnormalities causing age-dependent neurodegeneration and Parkinson's disease. J Neuroinflammation 2019; 16:153. [PMID: 31331333 PMCID: PMC6647317 DOI: 10.1186/s12974-019-1532-2] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 06/25/2019] [Indexed: 12/31/2022] Open
Abstract
This article describes pathogenic concepts and factors, in particular glycolipid abnormalities, that create cell dysfunction and synaptic loss in neurodegenerative diseases. By phenocopying lysosomal storage disorders, such as Gaucher disease and related disorders, age- and dose-dependent changes in glycolipid cell metabolism can lead to Parkinson's disease and related dementias. Recent results show that perturbation of sphingolipid metabolism can precede or is a part of abnormal protein handling in both genetic and idiopathic Parkinson's disease and Lewy body dementia. In aging and genetic predisposition with lipid disturbance, α-synuclein's normal vesicular and synaptic role may be detrimentally shifted toward accommodating and binding such lipids. Specific neuronal glycolipid, protein, and vesicular interactions create potential pathophysiology that is amplified by astroglial and microglial immune mechanisms resulting in neurodegeneration. This perspective provides a new logic for therapeutic interventions that do not focus on protein aggregation, but rather provides a guide to the complex biology and the common sequence of events that lead to age-dependent neurodegenerative disorders.
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Affiliation(s)
- Penelope J Hallett
- Neuroregeneration Research Institute, McLean Hospital/Harvard Medical School, Boston, USA
| | - Simone Engelender
- Neuroregeneration Research Institute, McLean Hospital/Harvard Medical School, Boston, USA.,Present Address: Department of Biochemistry, Rappaport Faculty of Medicine and Research Institute, Technion-Israel Institute of Technology, 31096, Haifa, Israel
| | - Ole Isacson
- Neuroregeneration Research Institute, McLean Hospital/Harvard Medical School, Boston, USA.
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17
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Rovere M, Powers AE, Jiang H, Pitino JC, Fonseca-Ornelas L, Patel DS, Achille A, Langen R, Varkey J, Bartels T. E46K-like α-synuclein mutants increase lipid interactions and disrupt membrane selectivity. J Biol Chem 2019; 294:9799-9812. [PMID: 31048377 PMCID: PMC6597829 DOI: 10.1074/jbc.ra118.006551] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 05/01/2019] [Indexed: 01/01/2023] Open
Abstract
Parkinson's disease (PD) is one of the most common neurodegenerative disorders, and both genetic and histopathological evidence have implicated the ubiquitous presynaptic protein α-synuclein (αSyn) in its pathogenesis. Recent work has investigated how disrupting αSyn's interaction with membranes triggers trafficking defects, cellular stress, and apoptosis. Special interest has been devoted to a series of mutants exacerbating the effects of the E46K mutation (associated with autosomal dominant PD) through homologous Glu-to-Lys substitutions in αSyn's N-terminal region (i.e. E35K and E61K). Such E46K-like mutants have been shown to cause dopaminergic neuron loss and severe but L-DOPA-responsive motor defects in mouse overexpression models, presenting enormous translational potential for PD and other "synucleinopathies." In this work, using a variety of biophysical techniques, we characterize the molecular pathology of E46K-like αSyn mutants by studying their structure and membrane-binding and remodeling abilities. We find that, although a slight increase in the mutants' avidity for synaptic vesicle-like membranes can be detected, most of their deleterious effects are connected to their complete disruption of αSyn's curvature selectivity. Indiscriminate binding can shift αSyn's subcellular localization away from its physiological interactants at the synaptic bouton toward trafficking vesicles and organelles, as observed in E46K-like cellular and murine models, as well as in human pathology. In conclusion, our findings suggest that a loss of curvature selectivity, rather than increased membrane affinity, could be the critical dyshomeostasis in synucleinopathies.
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Affiliation(s)
- Matteo Rovere
- From the Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115
| | - Alex E Powers
- From the Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115
| | - Haiyang Jiang
- From the Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115
| | - Julia C Pitino
- From the Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115
| | - Luis Fonseca-Ornelas
- From the Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115
| | - Dushyant S Patel
- From the Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115
| | - Alessandro Achille
- the Department of Computer Science, University of California, Los Angeles, California 90095
| | - Ralf Langen
- the Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, California 90033, and
| | - Jobin Varkey
- the Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, California 90033, and
| | - Tim Bartels
- From the Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115,
- the Dementia Research Institute, University College London, London WC1E 6BT, United Kingdom
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18
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O'Leary EI, Lee JC. Interplay between α-synuclein amyloid formation and membrane structure. BIOCHIMICA ET BIOPHYSICA ACTA. PROTEINS AND PROTEOMICS 2019; 1867:483-491. [PMID: 30287222 PMCID: PMC6445794 DOI: 10.1016/j.bbapap.2018.09.012] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 08/08/2018] [Accepted: 09/25/2018] [Indexed: 12/23/2022]
Abstract
Amyloid formation is a pathological hallmark of many neurodegenerative diseases, including Alzheimer's, Parkinson's, and Huntington's. While it is unknown how these disorders are initiated, in vitro and cellular experiments confirm the importance of membranes. Ubiquitous in vivo, membranes induce conformational changes in amyloidogenic proteins and in some cases, facilitate aggregation. Reciprocally, perturbations in the bilayer structure can be induced by amyloid formation. Here, we review studies in the last 10 years describing α-synuclein (α-syn) and its interactions with membranes, detailing the roles of anionic and zwitterionic lipids in aggregation, and their contribution to Parkinson's disease. We summarize the impact of α-syn - comparing monomeric, oligomeric, and fibrillar forms - on membrane structure, and the effect of membrane remodeling on amyloid formation. Finally, perspective on future studies investigating the interplay between α-syn aggregation and membranes is discussed. This article is part of a Special Issue entitled: Amyloids.
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Affiliation(s)
- Emma I O'Leary
- Laboratory of Protein Conformation and Dynamics, Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, United States
| | - Jennifer C Lee
- Laboratory of Protein Conformation and Dynamics, Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, United States.
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19
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Falke M, Victor J, Wördehoff MM, Peduzzo A, Zhang T, Schröder GF, Buell AK, Hoyer W, Etzkorn M. α-Synuclein-derived lipoparticles in the study of α-Synuclein amyloid fibril formation. Chem Phys Lipids 2019; 220:57-65. [PMID: 30826264 PMCID: PMC6451039 DOI: 10.1016/j.chemphyslip.2019.02.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 02/21/2019] [Accepted: 02/22/2019] [Indexed: 12/23/2022]
Abstract
Aggregation of the protein α-Synuclein (αSyn) is of great interest due to its involvement in the pathology of Parkinson’s disease. However, under in vitro conditions αSyn is very soluble and kinetically stable for extended time periods. As a result, most αSyn aggregation assays rely on conditions that artificially induce or enhance aggregation, often by introducing rather non-native conditions. It has been shown that αSyn interacts with membranes and conditions have been identified in which membranes can promote as well as inhibit αSyn aggregation. It has also been shown that αSyn has the intrinsic capability to assemble lipid-protein-particles, in a similar way as apolipoproteins can form lipid-bilayer nanodiscs. Here we show that these αSyn-lipid particles (αSyn-LiPs) can also effectively induce, accelerate or inhibit αSyn aggregation, depending on the applied conditions. αSyn-LiPs therefore provide a general platform and additional tool, complementary to other setups, to study various aspects of αSyn amyloid fibril formation.
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Affiliation(s)
- Marcel Falke
- Institut für Physikalische Biologie, Heinrich-Heine-University Düsseldorf, Germany
| | - Julian Victor
- Institut für Physikalische Biologie, Heinrich-Heine-University Düsseldorf, Germany
| | - Michael M Wördehoff
- Institut für Physikalische Biologie, Heinrich-Heine-University Düsseldorf, Germany
| | - Alessia Peduzzo
- Institut für Physikalische Biologie, Heinrich-Heine-University Düsseldorf, Germany
| | - Tao Zhang
- Institut für Physikalische Biologie, Heinrich-Heine-University Düsseldorf, Germany
| | - Gunnar F Schröder
- Institute of Complex Systems (ICS-6), Forschungszentrum Jülich, Germany
| | - Alexander K Buell
- Institut für Physikalische Biologie, Heinrich-Heine-University Düsseldorf, Germany
| | - Wolfgang Hoyer
- Institut für Physikalische Biologie, Heinrich-Heine-University Düsseldorf, Germany
| | - Manuel Etzkorn
- Institut für Physikalische Biologie, Heinrich-Heine-University Düsseldorf, Germany; Institute of Complex Systems (ICS-6), Forschungszentrum Jülich, Germany.
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20
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Patel D, Xu C, Nagarajan S, Liu Z, Hemphill WO, Shi R, Uversky VN, Caldwell GA, Caldwell KA, Witt SN. Alpha-synuclein inhibits Snx3-retromer-mediated retrograde recycling of iron transporters in S. cerevisiae and C. elegans models of Parkinson's disease. Hum Mol Genet 2019; 27:1514-1532. [PMID: 29452354 DOI: 10.1093/hmg/ddy059] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Accepted: 02/12/2018] [Indexed: 01/31/2023] Open
Abstract
We probed the role of alpha-synuclein (α-syn) in modulating sorting nexin 3 (Snx3)-retromer-mediated recycling of iron transporters in Saccharomyces cerevisiae and Caenorhabditis elegans. In yeast, the membrane-bound heterodimer Fet3/Ftr1 is the high affinity iron importer. Fet3 is a membrane-bound multicopper ferroxidase, whose ferroxidase domain is orthologous to human ceruloplasmin (Cp), that oxidizes external Fe+2 to Fe+3; the Fe+3 ions then channel through the Ftr1 permease into the cell. When the concentration of external iron is low (<1 µM), Fet3/Ftr1 is maintained on the plasma membrane by retrograde endocytic-recycling; whereas, when the concentration of external iron is high (>10 µM), Fet3/Ftr1 is endocytosed and shunted to the vacuole for degradation. We discovered that α-syn expression phenocopies the high iron condition: under the low iron condition (<1 µM), α-syn inhibits Snx3-retromer-mediated recycling of Fet3/Ftr1 and instead shunts Fet3/Ftr1 into the multivesicular body pathway to the vacuole. α-Syn inhibits recycling by blocking the association of Snx3-mCherry molecules with endocytic vesicles, possibly by interfering with the binding of Snx3 to phosphatidylinositol-3-monophosphate. In C. elegans, transgenic worms expressing α-syn exhibit an age-dependent degeneration of dopaminergic neurons that is partially rescued by the iron chelator desferoxamine. This implies that α-syn-expressing dopaminergic neurons are susceptible to changes in iron neurotoxicity with age, whereby excess iron enhances α-syn-induced neurodegeneration. In vivo genetic analysis indicates that α-syn dysregulates iron homeostasis in worm dopaminergic neurons, possibly by inhibiting SNX-3-mediated recycling of a membrane-bound ortholog of Cp (F21D5.3), the iron exporter ferroportin (FPN1.1), or both.
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Affiliation(s)
- Dhaval Patel
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, Shreveport, LA 71130, USA
| | - Chuan Xu
- Department of Biological Sciences, The University of Alabama, Tuscaloosa, AL 35487, USA
| | - Sureshbabu Nagarajan
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, Shreveport, LA 71130, USA
| | - Zhengchang Liu
- Department of Biological Sciences, The University of New Orleans, New Orleans, LA 70148, USA
| | - Wayne O Hemphill
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, Shreveport, LA 71130, USA
| | - Runhua Shi
- Department of Medicine, Feist-Weiller Cancer Center, Louisiana State University Health Sciences Center, Shreveport, LA 71130, USA
| | - Vladimir N Uversky
- Department of Molecular Medicine, USF Health Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA
| | - Guy A Caldwell
- Department of Biological Sciences, The University of Alabama, Tuscaloosa, AL 35487, USA
| | - Kim A Caldwell
- Department of Biological Sciences, The University of Alabama, Tuscaloosa, AL 35487, USA
| | - Stephan N Witt
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, Shreveport, LA 71130, USA.,Pharmacology, Toxicology and Neuroscience, Louisiana State University Health Sciences Center, Shreveport, LA 71130, USA
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21
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Pan J, Dalzini A, Khadka NK, Aryal CM, Song L. Lipid Extraction by α-Synuclein Generates Semi-Transmembrane Defects and Lipoprotein Nanoparticles. ACS OMEGA 2018; 3:9586-9597. [PMID: 30198000 PMCID: PMC6120733 DOI: 10.1021/acsomega.8b01462] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 08/07/2018] [Indexed: 05/17/2023]
Abstract
Modulations of synaptic membranes play an essential role in the physiological and pathological functions of the presynaptic protein α-synuclein (αSyn). Here we used solution atomic force microscopy (AFM) and electron paramagnetic resonance (EPR) spectroscopy to investigate membrane modulations caused by αSyn. We used several lipid bilayers to explore how different lipid species may regulate αSyn-membrane interactions. We found that at a protein-to-lipid ratio of ∼1/9, αSyn perturbed lipid bilayers by generating semi-transmembrane defects that only span one leaflet. In addition, αSyn coaggregates with lipid molecules to produce ∼10 nm-sized lipoprotein nanoparticles. The obtained AFM data are consistent with the apolipoprotein characteristic of αSyn. The role of anionic lipids was elucidated by comparing results from zwitterionic and anionic lipid bilayers. Specifically, our AFM measurements showed that anionic bilayers had a larger tendency of forming bilayer defects; similarly, our EPR measurements revealed that anionic bilayers exhibited more substantial changes in lipid chain mobility and bilayer polarity. We also studied the effect of cholesterol. We found that cholesterol increased the capability of αSyn in inducing bilayer defects and altering lipid chain mobility and bilayer polarity. These data can be explained by an increase in the lipid headgroup-headgroup spacing and/or specific cholesterol-αSyn interactions. Interestingly, we found an inhibitory effect of the cone-shaped phosphatidylethanolamine lipids on αSyn-induced bilayer remodeling. We explained our data by considering interlipid hydrogen-bonding that can stabilize bilayer organization and suppress lipid extraction. Our results of lipid-dependent membrane modulations are likely relevant to αSyn functioning.
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Affiliation(s)
- Jianjun Pan
- Department
of Physics, University of South Florida, Tampa, Florida 33620, United States
- E-mail: (J.P.)
| | - Annalisa Dalzini
- National
High Magnetic Field Laboratory, Florida
State University, Tallahassee, Florida 32310, United States
| | - Nawal K. Khadka
- Department
of Physics, University of South Florida, Tampa, Florida 33620, United States
| | - Chinta M. Aryal
- Department
of Physics, University of South Florida, Tampa, Florida 33620, United States
| | - Likai Song
- National
High Magnetic Field Laboratory, Florida
State University, Tallahassee, Florida 32310, United States
- E-mail: (L.S.)
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22
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Ekanayake V, Nisan D, Ryzhov P, Yao Y, Marassi FM. Lipoprotein Particle Formation by Proapoptotic tBid. Biophys J 2018; 115:533-542. [PMID: 30017071 DOI: 10.1016/j.bpj.2018.06.021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 06/13/2018] [Accepted: 06/19/2018] [Indexed: 10/28/2022] Open
Abstract
The interactions of Bcl-2 family proteins with intracellular lipids are essential for the regulation of apoptosis, a mechanism of programmed cell death that is central to the health and development of multicellular organisms. Bid and its caspase-8 cleavage product, tBid, promote the permeabilization of the mitochondrial outer membrane and sequester antiapoptotic Bcl-2 proteins to counter their cytoprotective activity. Bid and tBid also promote lipid exchange, a characteristic trait of apoptosis. Here, we show that tBid is capable of associating with phospholipids to form soluble, nanometer-sized lipoprotein particles that retain binding affinity for the antiapoptotic protein Bcl-xL. The tBid lipoprotein particles form with a lipid/protein stoichiometry in the range of 20/1 and have a diameter of ∼11.5 nm. Lipoparticle-bound tBid retains an α-helical structure and binds Bcl-xL through its third Bcl-2 homology motif, forming a soluble, lipid-associated heteroprotein complex. The results shed light on the role of lipids in mediating Bcl-2 protein mobility and interactions.
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Affiliation(s)
- Vindana Ekanayake
- Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California
| | - Danielle Nisan
- Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California
| | - Pavel Ryzhov
- Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California
| | - Yong Yao
- Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California
| | - Francesca M Marassi
- Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California.
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23
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George G, Singh S, Lokappa SB, Varkey J. Gene co-expression network analysis for identifying genetic markers in Parkinson's disease - a three-way comparative approach. Genomics 2018; 111:819-830. [PMID: 29852216 DOI: 10.1016/j.ygeno.2018.05.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 04/16/2018] [Accepted: 05/06/2018] [Indexed: 12/30/2022]
Abstract
Parkinson's disease (PD) is a neurodegenerative disorder involving progressive deterioration of dopaminergic neurons. Although few genetic markers for familial PD are known, the etiology of sporadic PD remains poorly understood. Microarray data was analysed for induced pluripotent stem cells (iPSCs) derived from PD patients and mature neuronal cells (mDA) differentiated from these iPSCs. Combining expression and semantic similarity, a highly-correlated PD interactome was constructed that included interactions of established Parkinson's disease marker genes. A novel three-way comparative approach was employed, delineating topologically and functionally important genes. These genes showed involvement in pathways like Parkin-ubiquitin proteosomal system (UPS), immune associated biological processes and apoptosis. Of interest are three genes, eEF1A1, CASK, and PSMD6 that are linked to PARK2 activity in the cell and thereby form attractive candidate genes for understanding PD. Network biology approach delineated in this study can be applied to other neurodegenerative disorders for identification of important genetic regulators.
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Affiliation(s)
- Gincy George
- Department of Bioinformatics, Karunya University, Karunya Nagar, Tamil Nadu 641114, India
| | - Sachidanand Singh
- Department of Bioinformatics, Karunya University, Karunya Nagar, Tamil Nadu 641114, India; Institute of Bio-Sciences and Technology, Shri Ramswaroop Memorial University, Deva Road, Uttar Pradesh 225003, India
| | - Sowmya Bekshe Lokappa
- Department of Bioinformatics, Karunya University, Karunya Nagar, Tamil Nadu 641114, India; Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, CA 90033, USA.
| | - Jobin Varkey
- Department of Bioinformatics, Karunya University, Karunya Nagar, Tamil Nadu 641114, India; Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, CA 90033, USA.
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24
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Galvagnion C. The Role of Lipids Interacting with α-Synuclein in the Pathogenesis of Parkinson's Disease. JOURNAL OF PARKINSONS DISEASE 2018; 7:433-450. [PMID: 28671142 DOI: 10.3233/jpd-171103] [Citation(s) in RCA: 175] [Impact Index Per Article: 29.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
α-synuclein is a small protein abundantly expressed in the brain and mainly located in synaptic terminals. The conversion of α-synuclein into oligomers and fibrils is the hallmark of a range of neurodegenerative disorders including Parkinson's disease and dementia with Lewy bodies. α-synuclein is disordered in solution but can adopt an α-helical conformation upon binding to lipid membranes. This lipid-protein interaction plays an important role in its proposed biological function, i.e., synaptic plasticity, but can also entail the aggregation of the protein. Both the chemical properties of the lipids and the lipid-to-protein-ratio have been reported to modulate the aggregation propensity of α-synuclein. In this review, the influence of changes in the nature and levels of lipids on the aggregation propensity of α-synuclein in vivo and in vitro will be discussed within a common general framework. In particular, while biophysical measurements and kinetic analyses of the time courses of α-synuclein aggregation in the presence of different types of lipid vesicles allow a mechanistic dissection of the influence of the lipids on α-synuclein aggregation, biological studies of cellular and animal models of Parkinson's disease allow the determination of changes in lipid levels and properties associated with the disease.
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Affiliation(s)
- Céline Galvagnion
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany.,Institute of Physical Biology, Heinrich Heine Universität, Düsseldorf, Germany
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25
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Rawat A, Langen R, Varkey J. Membranes as modulators of amyloid protein misfolding and target of toxicity. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:1863-1875. [PMID: 29702073 DOI: 10.1016/j.bbamem.2018.04.011] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 04/19/2018] [Accepted: 04/19/2018] [Indexed: 12/15/2022]
Abstract
Abnormal protein aggregation is a hallmark of various human diseases. α-Synuclein, a protein implicated in Parkinson's disease, is found in aggregated form within Lewy bodies that are characteristically observed in the brains of PD patients. Similarly, deposits of aggregated human islet amyloid polypeptide (IAPP) are found in the pancreatic islets in individuals with type 2 diabetes mellitus. Significant number of studies have focused on how monomeric, disaggregated proteins transition into various amyloid structures leading to identification of a vast number of aggregation promoting molecules and processes over the years. Inasmuch as these factors likely enhance the formation of toxic, misfolded species, they might act as risk factors in disease. Cellular membranes, and particularly certain lipids, are considered to be among the major players for aggregation of α-synuclein and IAPP, and membranes might also be the target of toxicity. Past studies have utilized an array of biophysical tools, both in vitro and in vivo, to expound the membrane-mediated aggregation. Here, we focus on membrane interaction of α-synuclein and IAPP, and how various kinds of membranes catalyze or modulate the aggregation of these proteins and how, in turn, these proteins disrupt membrane integrity, both in vitro and in vivo. The membrane interaction and subsequent aggregation has been briefly contrasted to aggregation of α-synuclein and IAPP in solution. This article is part of a Special Issue entitled: Protein Aggregation and Misfolding at the Cell Membrane Interface edited by Ayyalusamy Ramamoorthy.
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Affiliation(s)
- Anoop Rawat
- Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, CA 90033, United States
| | - Ralf Langen
- Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, CA 90033, United States.
| | - Jobin Varkey
- Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, CA 90033, United States.
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26
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Jiang Z, Flynn JD, Teague WE, Gawrisch K, Lee JC. Stimulation of α-synuclein amyloid formation by phosphatidylglycerol micellar tubules. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:1840-1847. [PMID: 29501608 DOI: 10.1016/j.bbamem.2018.02.025] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Revised: 02/23/2018] [Accepted: 02/25/2018] [Indexed: 10/25/2022]
Abstract
α-Synuclein (α-Syn) is a presynaptic protein that is accumulated in its amyloid form in the brains of Parkinson's patients. Although its biological function remains unclear, α-syn has been suggested to bind to synaptic vesicles and facilitate neurotransmitter release. Recently, studies have found that α-syn induces membrane tubulation, highlighting a potential mechanism for α-syn to stabilize highly curved membrane structures which could have both functional and dysfunctional consequences. To understand how membrane remodeling by α-syn affects amyloid formation, we have studied the α-syn aggregation process in the presence of phosphatidylglycerol (PG) micellar tubules, which were the first reported example of membrane tubulation by α-syn. Aggregation kinetics, β-sheet content, and macroscopic protein-lipid structures were observed by Thioflavin T fluorescence, circular dichroism spectroscopy and transmission electron microscopy, respectively. Collectively, the presence of PG micellar tubules formed at a stochiometric (L/P = 1) ratio was found to stimulate α-syn fibril formation. Moreover, transmission electron microscopy and solid-state nuclear magnetic resonance spectroscopy revealed the co-assembly of PG and α-syn into fibril structures. However, isolated micellar tubules do not form fibrils by themselves, suggesting an important role of free α-syn monomers during amyloid formation. In contrast, fibrils did not form in the presence of excess PG lipids (≥L/P = 50), where most of the α-syn molecules are in a membrane-bound α-helical form. Our results provide new mechanistic insights into how membrane tubules modulate α-syn amyloid formation and support a pivotal role of protein-lipid interaction in the dysfunction of α-syn.
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Affiliation(s)
- Zhiping Jiang
- Laboratory of Protein Conformation and Dynamics, Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jessica D Flynn
- Laboratory of Protein Conformation and Dynamics, Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Walter E Teague
- Laboratory of Membrane Biochemistry and Biophysics, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892, USA
| | - Klaus Gawrisch
- Laboratory of Membrane Biochemistry and Biophysics, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jennifer C Lee
- Laboratory of Protein Conformation and Dynamics, Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA.
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27
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Surguchov A. Commentary: α-Synuclein Interacts with Lipoproteins in Plasma. Front Mol Neurosci 2017; 10:362. [PMID: 29163037 PMCID: PMC5673846 DOI: 10.3389/fnmol.2017.00362] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 10/20/2017] [Indexed: 11/23/2022] Open
Affiliation(s)
- Andrei Surguchov
- Department of Neurology, Kansas University of Medical Center Research Institute, Kansas City, MI, United States
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28
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Tapeinos C, Battaglini M, Ciofani G. Advances in the design of solid lipid nanoparticles and nanostructured lipid carriers for targeting brain diseases. J Control Release 2017; 264:306-332. [PMID: 28844756 PMCID: PMC6701993 DOI: 10.1016/j.jconrel.2017.08.033] [Citation(s) in RCA: 293] [Impact Index Per Article: 41.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Revised: 08/23/2017] [Accepted: 08/23/2017] [Indexed: 12/13/2022]
Abstract
Solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs) comprise a category of versatile drug delivery systems that have been used in the biomedical field for >25years. SLNs and NLCs have been used for the treatment of various diseases including cardiovascular and cerebrovascular, and are considered a standard treatment for the latter, due to their inherent ability to cross the blood brain barrier (BBB). In this review, a presentation of the most important brain diseases (brain cancer, ischemic stroke, Alzheimer's disease, Parkinson's disease and multiple sclerosis) is approached, followed by the basic fabrication techniques of SLNs and NLCs. A detailed description of the reported studies of the last seven years, of active and passive targeting SLNs and NLCs for the treatment of glioblastoma multiforme and of other brain cancers, as well as for the treatment of neurodegenerative diseases is also carried out. Finally, a brief description of the advantages, the disadvantages, and the future perspectives in the use of these nanocarriers is reported, aiming at giving an insight of the limitations that have to be overcome in order to result in a delivery system with high therapeutic efficacy and without the limitations of the existing nano-systems.
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Affiliation(s)
- Christos Tapeinos
- Istituto Italiano di Tecnologia, Smart Bio-Interfaces, Viale Rinaldo Piaggio 34, 56025 Pontedera, PI, Italy.
| | - Matteo Battaglini
- Istituto Italiano di Tecnologia, Smart Bio-Interfaces, Viale Rinaldo Piaggio 34, 56025 Pontedera, PI, Italy; Scuola Superiore Sant'Anna, The Biorobotics Institute, Viale Rinaldo Piaggio 34, 56025 Pontedera, PI, Italy
| | - Gianni Ciofani
- Istituto Italiano di Tecnologia, Smart Bio-Interfaces, Viale Rinaldo Piaggio 34, 56025 Pontedera, PI, Italy; Politecnico di Torino, Department of Mechanical and Aerospace Engineering, Corso Duca degli Abruzzi 24, 10129 Torino, Italy.
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29
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Hsiao JHT, Halliday GM, Kim WS. α-Synuclein Regulates Neuronal Cholesterol Efflux. Molecules 2017; 22:molecules22101769. [PMID: 29048372 PMCID: PMC6151759 DOI: 10.3390/molecules22101769] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 10/18/2017] [Accepted: 10/19/2017] [Indexed: 12/15/2022] Open
Abstract
α-Synuclein is a neuronal protein that is at the center of focus in understanding the etiology of a group of neurodegenerative diseases called α-synucleinopathies, which includes Parkinson's disease (PD). Despite much research, the exact physiological function of α-synuclein is still unclear. α-Synuclein has similar biophysical properties as apolipoproteins and other lipid-binding proteins and has a high affinity for cholesterol. These properties suggest a possible role for α-synuclein as a lipid acceptor mediating cholesterol efflux (the process of removing cholesterol out of cells). To test this concept, we "loaded" SK-N-SH neuronal cells with fluorescently-labelled cholesterol, applied exogenous α-synuclein, and measured the amount of cholesterol removed from the cells using a classic cholesterol efflux assay. We found that α-synuclein potently stimulated cholesterol efflux. We found that the process was dose and time dependent, and was saturable at 1.0 µg/mL of α-synuclein. It was also dependent on the transporter protein ABCA1 located on the plasma membrane. We reveal for the first time a novel role of α-synuclein that underscores its importance in neuronal cholesterol regulation, and identify novel therapeutic targets for controlling cellular cholesterol levels.
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Affiliation(s)
- Jen-Hsiang T Hsiao
- Brain and Mind Centre, Sydney Medical School, The University of Sydney, Sydney NSW 2050, Australia.
- Neuroscience Research Australia, Sydney NSW 2031, Australia.
- School of Medical Sciences, University of New South Wales, Sydney NSW 2052, Australia.
| | - Glenda M Halliday
- Brain and Mind Centre, Sydney Medical School, The University of Sydney, Sydney NSW 2050, Australia.
- Neuroscience Research Australia, Sydney NSW 2031, Australia.
- School of Medical Sciences, University of New South Wales, Sydney NSW 2052, Australia.
| | - Woojin Scott Kim
- Brain and Mind Centre, Sydney Medical School, The University of Sydney, Sydney NSW 2050, Australia.
- Neuroscience Research Australia, Sydney NSW 2031, Australia.
- School of Medical Sciences, University of New South Wales, Sydney NSW 2052, Australia.
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30
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Abstract
Parkinson's disease (PD) is an age-related neurodegenerative disorder characterized by dopaminergic neural cell death in the substantia nigra of the brain and α-synuclein (α-syn) accumulation in Lewy bodies. α-Syn can be detected in blood and is a potential biomarker for PD. It has been shown recently that α-syn can pass through the blood-brain barrier (BBB), but the mechanism is not yet understood. We hypothesized that α-syn could interact with lipoproteins, and in association with these particles, could pass through the BBB. Here, we show that apoE, apoJ, and apoA1, but not apoB, were co-immunocaptured along with α-syn from human blood plasma, suggesting that α-syn is associated with high-density lipoproteins (HDL). This association was also supported by experiments involving western blotting of plasma fractions separated by gel filtration, which revealed that α-syn was found in fractions identified as HDL. Interestingly, we could also detect α-syn and ApoJ in the intermediate fraction between HDL and LDL, referred to as lipoprotein (a) (Lp(a)), which has an important role in cholesterol metabolism. Overall, the results provide best support for the hypothesis that α-syn interacts with HDL, and this has potential implications for transport of α-syn from the brain to peripheral blood, across the BBB.
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31
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Varkey J, Langen R. Membrane remodeling by amyloidogenic and non-amyloidogenic proteins studied by EPR. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2017; 280:127-139. [PMID: 28579098 PMCID: PMC5461824 DOI: 10.1016/j.jmr.2017.02.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Revised: 02/18/2017] [Accepted: 02/18/2017] [Indexed: 06/07/2023]
Abstract
The advancement in site-directed spin labeling of proteins has enabled EPR studies to expand into newer research areas within the umbrella of protein-membrane interactions. Recently, membrane remodeling by amyloidogenic and non-amyloidogenic proteins has gained a substantial interest in relation to driving and controlling vital cellular processes such as endocytosis, exocytosis, shaping of organelles like endoplasmic reticulum, Golgi and mitochondria, intracellular vesicular trafficking, formation of filopedia and multivesicular bodies, mitochondrial fusion and fission, and synaptic vesicle fusion and recycling in neurotransmission. Misregulation in any of these processes due to an aberrant protein (mutation or misfolding) or alteration of lipid metabolism can be detrimental to the cell and cause disease. Dissection of the structural basis of membrane remodeling by proteins is thus quite necessary for an understanding of the underlying mechanisms, but it remains a formidable task due to the difficulties of various common biophysical tools in monitoring the dynamic process of membrane binding and bending by proteins. This is largely since membranes generally complicate protein structure analysis and this problem is amplified for structural analysis in the presence of different types of membrane curvatures. Recent EPR studies on membrane remodeling by proteins show that a significant structural information can be generated to delineate the role of different protein modules, domains and individual amino acids in the generation of membrane curvature. These studies also show how EPR can complement the data obtained by high resolution techniques such as X-ray and NMR. This perspective covers the application of EPR in recent studies for understanding membrane remodeling by amyloidogenic and non-amyloidogenic proteins that is useful for researchers interested in using or complimenting EPR to gain better understanding of membrane remodeling. We also discuss how a single protein can generate different type of membrane curvatures using specific conformations for specific membrane structures and how EPR is a versatile tool well-suited to analyze subtle alterations in structures under such modifying conditions which otherwise would have been difficult using other biophysical tools.
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Affiliation(s)
- Jobin Varkey
- Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, CA 90033, United States.
| | - Ralf Langen
- Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, CA 90033, United States.
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32
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Ruzafa D, Hernandez-Gomez YS, Bisello G, Broersen K, Morel B, Conejero-Lara F. The influence of N-terminal acetylation on micelle-induced conformational changes and aggregation of α-Synuclein. PLoS One 2017; 12:e0178576. [PMID: 28562630 PMCID: PMC5451137 DOI: 10.1371/journal.pone.0178576] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2017] [Accepted: 05/15/2017] [Indexed: 12/15/2022] Open
Abstract
The biological function of α-Synuclein has been related to binding to lipids and membranes but these interactions can also mediate α-Synuclein aggregation, which is associated to Parkinson’s disease and other neuropathologies. In brain tissue α-Synuclein is constitutively N-acetylated, a modification that plays an important role in its conformational propensity, lipid and membrane binding, and aggregation propensity. We studied the interactions of the lipid-mimetic SDS with N-acetylated and non-acetylated α-Synuclein, as well as their early-onset Parkinson’s disease variants A30P, E46K and A53T. At low SDS/protein ratios α-Synuclein forms oligomeric complexes with SDS micelles with relatively low α-helical structure. These micellar oligomers can efficiently nucleate aggregation of monomeric α-Synuclein, with successive formation of oligomers, protofibrils, curly fibrils and mature amyloid fibrils. N-acetylation reduces considerably the rate of aggregation of WT α-Synuclein. However, in presence of any of the early-onset Parkinson’s disease mutations the protective effect of N-acetylation against micelle-induced aggregation becomes impaired. At higher SDS/protein ratios, N-acetylation favors another conformational transition, in which a second type of α-helix-rich, non-aggregating oligomers become stabilized. Once again, the Parkinson’s disease mutations disconnect the influence of N-acetylation in promoting this transition. These results suggest a cooperative link between the N-terminus and the region of the mutations that may be important for α-Synuclein function.
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Affiliation(s)
- David Ruzafa
- Departamento de Química Física e Instituto de Biotecnología, Facultad de Ciencias, Universidad de Granada, Granada, Spain
| | - Yuriko S. Hernandez-Gomez
- Departamento de Química Física e Instituto de Biotecnología, Facultad de Ciencias, Universidad de Granada, Granada, Spain
| | - Giovanni Bisello
- Departamento de Química Física e Instituto de Biotecnología, Facultad de Ciencias, Universidad de Granada, Granada, Spain
| | - Kerensa Broersen
- Nanobiophysics Group, MIRA Institute for Biomedical Technology and Technical Medicine, Faculty of Science and Technology, Universiteit Twente, Enschede, The Netherlands
| | - Bertrand Morel
- Departamento de Química Física e Instituto de Biotecnología, Facultad de Ciencias, Universidad de Granada, Granada, Spain
| | - Francisco Conejero-Lara
- Departamento de Química Física e Instituto de Biotecnología, Facultad de Ciencias, Universidad de Granada, Granada, Spain
- * E-mail:
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33
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Abstract
Membrane proteins play a most important part in metabolism, signaling, cell motility, transport, development, and many other biochemical and biophysical processes which constitute fundamentals of life on the molecular level. Detailed understanding of these processes is necessary for the progress of life sciences and biomedical applications. Nanodiscs provide a new and powerful tool for a broad spectrum of biochemical and biophysical studies of membrane proteins and are commonly acknowledged as an optimal membrane mimetic system that provides control over size, composition, and specific functional modifications on the nanometer scale. In this review we attempted to combine a comprehensive list of various applications of nanodisc technology with systematic analysis of the most attractive features of this system and advantages provided by nanodiscs for structural and mechanistic studies of membrane proteins.
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Affiliation(s)
- Ilia G Denisov
- Department of Biochemistry and Department of Chemistry, University of Illinois , Urbana, Illinois 61801, United States
| | - Stephen G Sligar
- Department of Biochemistry and Department of Chemistry, University of Illinois , Urbana, Illinois 61801, United States
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34
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Eichmann C, Kumari P, Riek R. High-density lipoprotein-like particle formation of Synuclein variants. FEBS Lett 2017; 591:304-311. [PMID: 28027392 DOI: 10.1002/1873-3468.12543] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 12/21/2016] [Accepted: 12/21/2016] [Indexed: 11/11/2022]
Abstract
α-Synuclein (α-Syn) is an intrinsically disordered protein in solution whose fibrillar aggregates are the hallmark of Parkinson's disease (PD). Although the specific function of α-Syn is still unclear, its high structural plasticity is key for the interactions of α-Syn with biological membranes. Recently, it has been observed that α-Syn is able to form high-density lipoprotein-like (HDL-like) particles that are reminiscent of self-assembling phospholipid bilayer nanodiscs. Here, we extended our preparation method for the production of α-Syn lipoprotein particles to the β- and γ-Syn variants, and the PD-related familial α-Syn mutants. We show that all human Syns can form stable and homogeneous populations of HDL-like particles with distinct morphologies. Our results characterize the impact of the individual Syns on the formation capacity of these particles and indicate that Syn HDL-like particles are neither causing toxicity nor a toxicity-related loss of α-Syn in PD.
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Affiliation(s)
- Cédric Eichmann
- In-Cell NMR Laboratory, Department of NMR-supported Structural Biology, Leibniz Institute of Molecular Pharmacology (FMP Berlin), Berlin, Germany
| | - Pratibha Kumari
- Laboratory of Physical Chemistry, Swiss Federal Institute of Technology, Zürich, Switzerland
| | - Roland Riek
- Laboratory of Physical Chemistry, Swiss Federal Institute of Technology, Zürich, Switzerland
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35
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Breydo L, Redington JM, Uversky VN. Effects of Intrinsic and Extrinsic Factors on Aggregation of Physiologically Important Intrinsically Disordered Proteins. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2016; 329:145-185. [PMID: 28109327 DOI: 10.1016/bs.ircmb.2016.08.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Misfolding and aggregation of proteins and peptides play an important role in a number of diseases as well as in many physiological processes. Many of the proteins that misfold and aggregate in vivo are intrinsically disordered. Protein aggregation is a complex multistep process, and aggregates can significantly differ in morphology, structure, stability, cytotoxicity, and self-propagation ability. The aggregation process is influenced by both intrinsic (e.g., mutations and expression levels) and extrinsic (e.g., polypeptide chain truncation, macromolecular crowding, posttranslational modifications, as well as interaction with metal ions, other small molecules, lipid membranes, and chaperons) factors. This review examines the effect of a variety of these factors on aggregation of physiologically important intrinsically disordered proteins.
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Affiliation(s)
- L Breydo
- Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL, United States.
| | - J M Redington
- Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL, United States
| | - V N Uversky
- Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL, United States; Laboratory of Structural Dynamics, Stability and Folding of Proteins, Institute of Cytology, Russian Academy of Sciences, St. Petersburg, Russia.
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36
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Wang S, Zhang S, Xu C, Barron A, Galiano F, Patel D, Lee YJ, Caldwell GA, Caldwell KA, Witt SN. Chemical Compensation of Mitochondrial Phospholipid Depletion in Yeast and Animal Models of Parkinson's Disease. PLoS One 2016; 11:e0164465. [PMID: 27736935 PMCID: PMC5063346 DOI: 10.1371/journal.pone.0164465] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 09/26/2016] [Indexed: 01/08/2023] Open
Abstract
We have been investigating the role that phosphatidylethanolamine (PE) and phosphatidylcholine (PC) content plays in modulating the solubility of the Parkinson’s disease protein alpha-synuclein (α-syn) using Saccharomyces cerevisiae and Caenorhabditis elegans. One enzyme that synthesizes PE is the conserved enzyme phosphatidylserine decarboxylase (Psd1/yeast; PSD-1/worms), which is lodged in the inner mitochondrial membrane. We previously found that decreasing the level of PE due to knockdown of Psd1/psd-1 affects the homeostasis of α-syn in vivo. In S. cerevisiae, the co-occurrence of low PE and α-syn in psd1Δ cells triggers mitochondrial defects, stress in the endoplasmic reticulum, misprocessing of glycosylphosphatidylinositol-anchored proteins, and a 3-fold increase in the level of α-syn. The goal of this study was to identify drugs that rescue this phenotype. We screened the Prestwick library of 1121 Food and Drug Administration-approved drugs using psd1Δ + α-syn cells and identified cyclosporin A, meclofenoxate hydrochloride, and sulfaphenazole as putative protective compounds. The protective activity of these drugs was corroborated using C. elegans in which α-syn is expressed specifically in the dopaminergic neurons, with psd-1 depleted by RNAi. Worm populations were examined for dopaminergic neuron survival following psd-1 knockdown. Exposure to cyclosporine, meclofenoxate, and sulfaphenazole significantly enhanced survival at day 7 in α-syn-expressing worm populations whereby 50–55% of the populations displayed normal neurons, compared to only 10–15% of untreated animals. We also found that all three drugs rescued worms expressing α-syn in dopaminergic neurons that were deficient in the phospholipid cardiolipin following cardiolipin synthase (crls-1) depletion by RNAi. We discuss how these drugs might block α-syn pathology in dopaminergic neurons.
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Affiliation(s)
- Shaoxiao Wang
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, Shreveport, LA, United States of America
| | - Siyuan Zhang
- Department of Biological Sciences, The University of Alabama, Tuscaloosa, AL, United States of America
| | - Chuan Xu
- Department of Biological Sciences, The University of Alabama, Tuscaloosa, AL, United States of America
| | - Addie Barron
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, Shreveport, LA, United States of America
| | - Floyd Galiano
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, Shreveport, LA, United States of America
| | - Dhaval Patel
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, Shreveport, LA, United States of America
| | - Yong Joo Lee
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, Shreveport, LA, United States of America
| | - Guy A. Caldwell
- Department of Biological Sciences, The University of Alabama, Tuscaloosa, AL, United States of America
| | - Kim A. Caldwell
- Department of Biological Sciences, The University of Alabama, Tuscaloosa, AL, United States of America
| | - Stephan N. Witt
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, Shreveport, LA, United States of America
- Department of Pharmacology, Toxicology and Neuroscience, Louisiana State University Health Sciences Center, Shreveport, LA, United States of America
- * E-mail:
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37
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Lee JH, Ying J, Bax A. Nuclear Magnetic Resonance Observation of α-Synuclein Membrane Interaction by Monitoring the Acetylation Reactivity of Its Lysine Side Chains. Biochemistry 2016; 55:4949-59. [PMID: 27455358 PMCID: PMC5015657 DOI: 10.1021/acs.biochem.6b00637] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
The
interaction between α-synuclein (αS) protein and
lipid membranes is key to its role in synaptic vesicle homeostasis
and plays a role in initiating fibril formation, which is implicated
in Parkinson’s disease. The natural state of αS inside
the cell is generally believed to be intrinsically disordered, but
chemical cross-linking experiments provided evidence of a tetrameric
arrangement, which was reported to be rich in α-helical secondary
structure based on circular dichroism (CD). Cross-linking relies on
chemical modification of the protein’s Lys Cε amino groups, commonly by glutaraldehyde, or by disuccinimidyl glutarate
(DSG), with the latter agent preferred for cellular assays. We used
ultra-high-resolution homonuclear decoupled nuclear magnetic resonance
experiments to probe the reactivity of the 15 αS Lys residues
toward N-succinimidyl acetate, effectively half the
DSG cross-linker, which results in acetylation of Lys. The intensities
of both side chain and backbone amide signals of acetylated Lys residues
provide direct information about the reactivity, showing a difference
of a factor of 2.5 between the most reactive (K6) and the least reactive
(K102) residue. The presence of phospholipid vesicles decreases reactivity
of most Lys residues by up to an order of magnitude at high lipid:protein
stoichiometries (500:1), but only weakly at low ratios. The decrease
in Lys reactivity is found to be impacted by lipid composition, even
for vesicles that yield similar αS CD signatures. Our data provide
new insight into the αS–bilayer interaction, including
the pivotal state in which the available lipid surface is limited.
Protection of Lys Cε amino groups by αS–bilayer
interaction will strongly impact quantitative interpretation of DSG
cross-linking experiments.
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Affiliation(s)
- Jung Ho Lee
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health , Bethesda, Maryland 20892, United States
| | - Jinfa Ying
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health , Bethesda, Maryland 20892, United States
| | - Ad Bax
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health , Bethesda, Maryland 20892, United States
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38
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Okada AK, Teranishi K, Isas JM, Bedrood S, Chow RH, Langen R. Diabetic Risk Factors Promote Islet Amyloid Polypeptide Misfolding by a Common, Membrane-mediated Mechanism. Sci Rep 2016; 6:31094. [PMID: 27531121 PMCID: PMC4987648 DOI: 10.1038/srep31094] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 07/14/2016] [Indexed: 12/14/2022] Open
Abstract
The current diabetes epidemic is associated with a diverse set of risk factors including obesity and exposure to plastics. Notably, significant elevations of negatively charged amphiphilic molecules are observed in obesity (e.g. free fatty acids and phosphatidic acid) and plastics exposure (monophthalate esters). It remains unclear whether these factors share pathogenic mechanisms and whether links exist with islet amyloid polypeptide (IAPP) misfolding, a process central to β-cell dysfunction and death. Using a combination of fluorescence, circular dichroism and electron microscopy, we show that phosphatidic acid, oleic acid, and the phthalate metabolite MBzP partition into neutral membranes and enhance IAPP misfolding. The elevation of negative charge density caused by the presence of the risk factor molecules stabilizes a common membrane-bound α-helical intermediate that, in turn, facilitates IAPP misfolding. This shared mechanism points to a critical role for the membrane-bound intermediate in disease pathogenesis, making it a potential target for therapeutic intervention.
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Affiliation(s)
- Alan K Okada
- Department of Biochemistry and Molecular Biology, Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, California, USA
| | - Kazuki Teranishi
- Department of Biochemistry and Molecular Biology, Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, California, USA
| | - J Mario Isas
- Department of Biochemistry and Molecular Biology, Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, California, USA
| | - Sahar Bedrood
- USC Roski Eye Institute, Department of Ophthalmology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Robert H Chow
- Department of Physiology and Biophysics, Keck School of Medicine, Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, California, USA
| | - Ralf Langen
- Department of Biochemistry and Molecular Biology, Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, California, USA
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39
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Stewart PL. Cryo-electron microscopy and cryo-electron tomography of nanoparticles. WILEY INTERDISCIPLINARY REVIEWS-NANOMEDICINE AND NANOBIOTECHNOLOGY 2016; 9. [DOI: 10.1002/wnan.1417] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Revised: 05/11/2016] [Accepted: 06/02/2016] [Indexed: 01/04/2023]
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40
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Eftekharzadeh B, Hyman BT, Wegmann S. Structural studies on the mechanism of protein aggregation in age related neurodegenerative diseases. Mech Ageing Dev 2016; 156:1-13. [PMID: 27005270 DOI: 10.1016/j.mad.2016.03.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Revised: 02/12/2016] [Accepted: 03/03/2016] [Indexed: 01/09/2023]
Abstract
The progression of many neurodegenerative diseases is assumed to be caused by misfolding of specific characteristic diseases related proteins, resulting in aggregation and fibril formation of these proteins. Protein misfolding associated age related diseases, although different in disease manifestations, share striking similarities. In all cases, one disease protein aggregates and loses its function or additionally shows a toxic gain of function. However, the clear link between these individual amyloid-like protein aggregates and cellular toxicity is often still uncertain. The similar features of protein misfolding and aggregation in this group of proteins, all involved in age related neurodegenerative diseases, results in high interest in characterization of their structural properties. We review here recent findings on structural properties of some age related disease proteins, in the context of their biological importance in disease.
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Affiliation(s)
- Bahareh Eftekharzadeh
- Department of Neurology, Massachusetts General Hospital and Mass General Institute for Neurodegenerative Disease, Charlestown, MA 02129, USA.
| | - Bradley T Hyman
- Department of Neurology, Massachusetts General Hospital and Mass General Institute for Neurodegenerative Disease, Charlestown, MA 02129, USA
| | - Susanne Wegmann
- Department of Neurology, Massachusetts General Hospital and Mass General Institute for Neurodegenerative Disease, Charlestown, MA 02129, USA
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41
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Eichmann C, Campioni S, Kowal J, Maslennikov I, Gerez J, Liu X, Verasdonck J, Nespovitaya N, Choe S, Meier BH, Picotti P, Rizo J, Stahlberg H, Riek R. Preparation and Characterization of Stable α-Synuclein Lipoprotein Particles. J Biol Chem 2016; 291:8516-27. [PMID: 26846854 DOI: 10.1074/jbc.m115.707968] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Indexed: 01/11/2023] Open
Abstract
Multiple neurodegenerative diseases are caused by the aggregation of the human α-Synuclein (α-Syn) protein. α-Syn possesses high structural plasticity and the capability of interacting with membranes. Both features are not only essential for its physiological function but also play a role in the aggregation process. Recently it has been proposed that α-Syn is able to form lipid-protein particles reminiscent of high-density lipoproteins. Here, we present a method to obtain a stable and homogeneous population of nanometer-sized particles composed of α-Syn and anionic phospholipids. These particles are called α-Syn lipoprotein (nano)particles to indicate their relationship to high-density lipoproteins formed by human apolipoproteins in vivo and of in vitro self-assembling phospholipid bilayer nanodiscs. Structural investigations of the α-Syn lipoprotein particles by circular dichroism (CD) and magic angle solid-state nuclear magnetic resonance (MAS SS-NMR) spectroscopy establish that α-Syn adopts a helical secondary structure within these particles. Based on cryo-electron microscopy (cryo-EM) and dynamic light scattering (DLS) α-Syn lipoprotein particles have a defined size with a diameter of ∼23 nm. Chemical cross-linking in combination with solution-state NMR and multiangle static light scattering (MALS) of α-Syn particles reveal a high-order protein-lipid entity composed of ∼8-10 α-Syn molecules. The close resemblance in size between cross-linked in vitro-derived α-Syn lipoprotein particles and a cross-linked species of endogenous α-Syn from SH-SY5Y human neuroblastoma cells indicates a potential functional relevance of α-Syn lipoprotein nanoparticles.
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Affiliation(s)
| | | | - Julia Kowal
- Center for Cellular Imaging and NanoAnalytics, Biozentrum, University of Basel, Mattenstrasse 26, CH-4058 Basel, Switzerland
| | | | - Juan Gerez
- Institute of Biochemistry, Swiss Federal Institute of Technology, ETH-Hönggerberg, CH-8093 Zürich, Switzerland
| | - Xiaoxia Liu
- Department of Biophysics, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390
| | | | | | - Senyon Choe
- Structural Biology Laboratory, The Salk Institute, La Jolla, California 92037 and
| | | | - Paola Picotti
- Institute of Biochemistry, Swiss Federal Institute of Technology, ETH-Hönggerberg, CH-8093 Zürich, Switzerland
| | - Josep Rizo
- Department of Biophysics, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390
| | - Henning Stahlberg
- Center for Cellular Imaging and NanoAnalytics, Biozentrum, University of Basel, Mattenstrasse 26, CH-4058 Basel, Switzerland
| | - Roland Riek
- From the Laboratory of Physical Chemistry and Structural Biology Laboratory, The Salk Institute, La Jolla, California 92037 and
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42
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Abstract
BAR domains bend membranes by imposing their curved shape. In this issue, Isas et al. show the structural differences in the interaction of the BAR domain protein amphiphysin with vesicles and tubes. They find that superficial interactions lead to vesicles, whereas more penetrating interactions of a more crowded protein lead to tubes.
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Affiliation(s)
- Adrian Gross
- Department of Biochemistry and Molecular Biology, Rosalind Franklin University of Medicine and Science, 3333 Green Bay Road, North Chicago, IL 60064, USA.
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43
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Anunciado D, Rai DK, Qian S, Urban V, O'Neill H. Small-angle neutron scattering reveals the assembly of alpha-synuclein in lipid membranes. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2015; 1854:1881-1889. [PMID: 26321599 DOI: 10.1016/j.bbapap.2015.08.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Revised: 08/12/2015] [Accepted: 08/25/2015] [Indexed: 12/15/2022]
Abstract
The aggregation of α-synuclein (asyn), an intrinsically disordered protein (IDP), is a hallmark in Parkinson's disease (PD). We investigated the conformational changes that asyn undergoes in the presence of membrane and membrane mimetics using small-angle neutron scattering (SANS). In solution, asyn is monomeric and unfolded assuming an ensemble of conformers spanning extended and compact conformations. Using the contrast variation technique and SANS, the protein scattering signal in the membrane-protein complexes is selectively highlighted in order to monitor its conformational changes in this environment. We showed that in the presence of phospholipid membranes asyn transitions from a monodisperse state to aggregated structures with sizes ranging from 200 to 900Å coexisting with the monomeric species. Detailed SANS data analysis revealed that asyn aggregates have a hierarchical organization in which clusters of smaller asyn aggregates assemble to form the larger structures. This study provides new insight into the mechanism of asyn aggregation. We propose an aggregation mechanism in which stable asyn aggregates seed the aggregation process and hence the hierarchical assembly of structures. Our findings demonstrate that membrane-induced conformational changes in asyn lead to its heterogeneous aggregation which could be physiologically relevant in its function or in the diseased state.
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Affiliation(s)
- Divina Anunciado
- Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830, United States
| | - Durgesh K Rai
- Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830, United States
| | - Shuo Qian
- Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830, United States
| | - Volker Urban
- Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830, United States
| | - Hugh O'Neill
- Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830, United States
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44
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Kegulian NC, Sankhagowit S, Apostolidou M, Jayasinghe SA, Malmstadt N, Butler PC, Langen R. Membrane Curvature-sensing and Curvature-inducing Activity of Islet Amyloid Polypeptide and Its Implications for Membrane Disruption. J Biol Chem 2015; 290:25782-93. [PMID: 26283787 DOI: 10.1074/jbc.m115.659797] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Indexed: 11/06/2022] Open
Abstract
Islet amyloid polypeptide (IAPP) is a 37-amino acid amyloid protein intimately associated with pancreatic islet β-cell dysfunction and death in type II diabetes. In this study, we combine spectroscopic methods and microscopy to investigate α-helical IAPP-membrane interactions. Using light scattering and fluorescence microscopy, we observe that larger vesicles become smaller upon treatment with human or rat IAPP. Electron microscopy shows the formation of various highly curved structures such as tubules or smaller vesicles in a membrane-remodeling process, and spectrofluorometric detection of vesicle leakage shows disruption of membrane integrity. This effect is stronger for human IAPP than for the less toxic rat IAPP. From CD spectra in the presence of different-sized vesicles, we also uncover the membrane curvature-sensing ability of IAPP and find that it transitions from inducing to sensing membrane curvature when lipid negative charge is decreased. Our in vivo EM images of immunogold-labeled rat IAPP and human IAPP show both forms to localize to mitochondrial cristae, which contain not only locally curved membranes but also phosphatidylethanolamine and cardiolipin, lipids with high spontaneous negative curvature. Disruption of membrane integrity by induction of membrane curvature could apply more broadly to other amyloid proteins and be responsible for membrane damage observed in other amyloid diseases as well.
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Affiliation(s)
- Natalie C Kegulian
- From the Department of Biochemistry and Molecular Biology, Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, California 90033
| | - Shalene Sankhagowit
- the Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089, and
| | - Melania Apostolidou
- From the Department of Biochemistry and Molecular Biology, Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, California 90033
| | - Sajith A Jayasinghe
- From the Department of Biochemistry and Molecular Biology, Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, California 90033
| | - Noah Malmstadt
- the Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089, and
| | - Peter C Butler
- the Larry Hillblom Islet Research Center, David Geffen School of Medicine at UCLA, Los Angeles, California 90095
| | - Ralf Langen
- From the Department of Biochemistry and Molecular Biology, Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, California 90033,
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45
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New insights into cellular α-synuclein homeostasis in health and disease. Curr Opin Neurobiol 2015; 36:15-22. [PMID: 26282834 DOI: 10.1016/j.conb.2015.07.007] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2015] [Accepted: 07/24/2015] [Indexed: 12/15/2022]
Abstract
α-Synuclein (αSyn) is a highly abundant neuronal protein whose exact structure and function are under debate. Misfolding and aggregation of this normally soluble, 140-residue polypeptide underlies a group of neurodegenerative disorders called synucleinopathies, including Parkinson's disease (PD) and dementia with Lewy bodies (DLB). The αSyn field has focused increasing attention on the hypotheses that certain aggregates of αSyn may be directly toxic to the neurons in which they arise and/or that aggregates can be released from some neurons and diffuse by undefined mechanisms to other neurons to seed αSyn in the recipient cells, thus propagating neuropathology by a non-cell autonomous process ('pathogenic spread'). While intense interest in these hypotheses has led to new approaches and tools to model aspects of the disorders, it is important to analyze which molecular events initiate αSyn aggregation inside neurons in the first place. Here, we review new insights into how neuronal αSyn homeostasis may be maintained under physiological conditions but perturbed by pathological factors.
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46
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Breydo L, Uversky VN. Structural, morphological, and functional diversity of amyloid oligomers. FEBS Lett 2015; 589:2640-8. [PMID: 26188543 DOI: 10.1016/j.febslet.2015.07.013] [Citation(s) in RCA: 127] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Revised: 07/08/2015] [Accepted: 07/11/2015] [Indexed: 12/19/2022]
Abstract
Protein misfolding and aggregation are known to play a crucial role in a number of important human diseases (Alzheimer's, Parkinson's, prion, diabetes, cataracts, etc.) as well as in a multitude of physiological processes. Protein aggregation is a highly complex process resulting in a variety of aggregates with different structures and morphologies. Oligomeric protein aggregates (amyloid oligomers) are formed as both intermediates and final products of the aggregation process. They are believed to play an important role in many protein aggregation-related diseases, and many of them are highly cytotoxic. Due to their instability and structural heterogeneity, information about structure, mechanism of formation, and physiological effects of amyloid oligomers is sparse. This review attempts to summarize the existing information on the major properties of amyloid oligomers.
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Affiliation(s)
- Leonid Breydo
- Department of Molecular Medicine and Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA.
| | - Vladimir N Uversky
- Department of Molecular Medicine and Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA; Institute for Biological Instrumentation, Russian Academy of Sciences, Pushchino, Moscow Region, Russian Federation; Department of Biology, Faculty of Science, King Abdulaziz University, P.O. Box 80203, Jeddah 21589, Saudi Arabia.
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47
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Tubulation by amphiphysin requires concentration-dependent switching from wedging to scaffolding. Structure 2015; 23:873-881. [PMID: 25865245 DOI: 10.1016/j.str.2015.02.014] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Revised: 02/09/2015] [Accepted: 02/24/2015] [Indexed: 02/08/2023]
Abstract
BAR proteins are involved in a variety of membrane remodeling events but how they can mold membranes into different shapes remains poorly understood. Using electron paramagnetic resonance, we find that vesicle binding of the N-BAR protein amphiphysin is predominantly mediated by the shallow insertion of amphipathic N-terminal helices. In contrast, the interaction with tubes involves deeply inserted N-terminal helices together with the concave surface of the BAR domain, which acts as a scaffold. Combined with the observed concentration dependence of tubulation and BAR domain scaffolding, the data indicate that initial membrane deformations and vesicle binding are mediated by insertion of amphipathic helical wedges, while tubulation requires high protein densities at which oligomeric BAR domain scaffolds form. In addition, we identify a pocket of residues on the concave surface of the BAR domain that insert deeply into tube membrane. Interestingly, this pocket harbors a number of disease mutants in the homologous amphiphysin 2.
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48
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Basak S, Prasad GVRK, Varkey J, Chattopadhyay K. Early sodium dodecyl sulfate induced collapse of α-synuclein correlates with its amyloid formation. ACS Chem Neurosci 2015; 6:239-46. [PMID: 25369246 DOI: 10.1021/cn500168x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The aggregation of α-synuclein (A-syn) has been implicated strongly in Parkinson's disease (PD). In vitro studies established A-syn to be a member of the intrinsically disordered protein (IDP) family. This protein undergoes structural interconversion between an extended and a compact state, and this equilibrium influences the mechanism of its aggregation. A combination of fluorescence resonance energy transfer (FRET) and fluorescence correlation spectroscopy (FCS) has been used to study the membrane induced conformational reorganization and aggregation of A-syn. Different structural and conformational events, including the early collapse, the formation of the secondary structure, and aggregation have been identified and characterized using FCS and other biophysical methods. In addition, the concentrations of glycerol and urea have been varied to study the effect of solution conditions on the above conformational events. Further, we have extended this study on a number of A-syn mutants, namely, A30P, A53T, and E46K. These mutants are chosen because of their known implications in the disease pathology. The variation of solution conditions and mutational analyses suggest a strong correlation between the extent of early collapse and the onset of aggregation in PD.
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Affiliation(s)
- Sujit Basak
- Protein
Folding and Dynamics Laboratory Structural Biology and Bioinformatics
Division CSIR-Indian Institute of Chemical Biology (IICB) 4, Raja
S.C. Mullick Road, Kolkata-700032, India
| | - G. V. R Krishna Prasad
- Department
of Biological Sciences, Indian Institute of Science Education and Research, Sec 81, SAS Nagar, Mohali, Punjab-140306, India
| | - Jobin Varkey
- Centre
for Converging Technologies, University of Rajasthan, Jaipur-3002004, India
| | - Krishnananda Chattopadhyay
- Protein
Folding and Dynamics Laboratory Structural Biology and Bioinformatics
Division CSIR-Indian Institute of Chemical Biology (IICB) 4, Raja
S.C. Mullick Road, Kolkata-700032, India
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49
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α-synuclein multimers cluster synaptic vesicles and attenuate recycling. Curr Biol 2014; 24:2319-26. [PMID: 25264250 DOI: 10.1016/j.cub.2014.08.027] [Citation(s) in RCA: 192] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2014] [Revised: 08/01/2014] [Accepted: 08/13/2014] [Indexed: 11/24/2022]
Abstract
The normal functions and pathologic facets of the small presynaptic protein α-synuclein (α-syn) are of exceptional interest. In previous studies, we found that α-syn attenuates synaptic exo/endocytosis; however, underlying mechanisms remain unknown. More recent evidence suggests that α-syn exists as metastable multimers and not solely as a natively unfolded monomer. However, conformations of α-syn at synapses--its physiologic locale--are unclear, and potential implications of such higher-order conformations to synaptic function are unknown. Exploring α-syn conformations and synaptic function in neurons, we found that α-syn promptly organizes into physiological multimers at synapses. Furthermore, our experiments indicate that α-syn multimers cluster synaptic vesicles and restrict their motility, suggesting a novel role for these higher-order structures. Supporting this, α-syn mutations that disrupt multimerization also fail to restrict synaptic vesicle motility or attenuate exo/endocytosis. We propose a model in which α-syn multimers cluster synaptic vesicles, restricting their trafficking and recycling, and consequently attenuate neurotransmitter release.
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50
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α-Synuclein assembles into higher-order multimers upon membrane binding to promote SNARE complex formation. Proc Natl Acad Sci U S A 2014; 111:E4274-83. [PMID: 25246573 DOI: 10.1073/pnas.1416598111] [Citation(s) in RCA: 341] [Impact Index Per Article: 34.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Physiologically, α-synuclein chaperones soluble NSF attachment protein receptor (SNARE) complex assembly and may also perform other functions; pathologically, in contrast, α-synuclein misfolds into neurotoxic aggregates that mediate neurodegeneration and propagate between neurons. In neurons, α-synuclein exists in an equilibrium between cytosolic and membrane-bound states. Cytosolic α-synuclein appears to be natively unfolded, whereas membrane-bound α-synuclein adopts an α-helical conformation. Although the majority of studies showed that cytosolic α-synuclein is monomeric, it is unknown whether membrane-bound α-synuclein is also monomeric, and whether chaperoning of SNARE complex assembly by α-synuclein involves its cytosolic or membrane-bound state. Here, we show using chemical cross-linking and fluorescence resonance energy transfer (FRET) that α-synuclein multimerizes into large homomeric complexes upon membrane binding. The FRET experiments indicated that the multimers of membrane-bound α-synuclein exhibit defined intermolecular contacts, suggesting an ordered array. Moreover, we demonstrate that α-synuclein promotes SNARE complex assembly at the presynaptic plasma membrane in its multimeric membrane-bound state, but not in its monomeric cytosolic state. Our data delineate a folding pathway for α-synuclein that ranges from a monomeric, natively unfolded form in cytosol to a physiologically functional, multimeric form upon membrane binding, and show that only the latter but not the former acts as a SNARE complex chaperone at the presynaptic terminal, and may protect against neurodegeneration.
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