1
|
Rocha S, Kumar R, Nordén B, Wittung-Stafshede P. Orientation of α-Synuclein at Negatively Charged Lipid Vesicles: Linear Dichroism Reveals Time-Dependent Changes in Helix Binding Mode. J Am Chem Soc 2021; 143:18899-18906. [PMID: 34748321 PMCID: PMC8603351 DOI: 10.1021/jacs.1c05344] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
The neuronal protein
α-synuclein, linked to Parkinson’s
disease, binds to negatively charged vesicles adopting a partial α-helix
structure, but helix arrangement at the vesicle surface is not fully
understood. Using linear dichroism spectroscopy (LD), we study the
interaction of monomeric α-synuclein with large unilamellar
vesicles of 1,2-dioleoyl-sn-glycero-3-phospho-l-serine (DOPS), 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-l-serine (POPS), and 1,2-dioleoyl-sn-glycero-3-phospho-(1′-rac-glycerol) (DOPG) under mild shear flow. The LD data
of oriented lipid vesicles show that the long axis of the protein
helix is oriented preferentially perpendicular to the membrane normal
but deviates from a uniform in-plane distribution. Upon initial binding,
a fraction of helices are oriented in the direction of least curvature
for all ellipsoid-shaped vesicles at a lipid:protein molar ratio of
100. However, at a lower protein concentration the helices distribute
uniformly on DOPS and POPS vesicles. In all cases, the α-synuclein
helices rearrange with time (minute time scale) in the shear flow
and begin to tilt into the vesicle membrane. Faster reorientation
kinetics in the presence of flow suggests that modulation of membrane
dynamics, by thermal or shear-dynamic activation, may overcome steric
barriers by what may be called “flow catalysis”.
Collapse
|
2
|
Antonschmidt L, Dervişoğlu R, Sant V, Tekwani Movellan K, Mey I, Riedel D, Steinem C, Becker S, Andreas LB, Griesinger C. Insights into the molecular mechanism of amyloid filament formation: Segmental folding of α-synuclein on lipid membranes. SCIENCE ADVANCES 2021; 7:7/20/eabg2174. [PMID: 33990334 PMCID: PMC8121418 DOI: 10.1126/sciadv.abg2174] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 03/25/2021] [Indexed: 05/15/2023]
Abstract
Recent advances in the structural biology of disease-relevant α-synuclein fibrils have revealed a variety of structures, yet little is known about the process of fibril aggregate formation. Characterization of intermediate species that form during aggregation is crucial; however, this has proven very challenging because of their transient nature, heterogeneity, and low population. Here, we investigate the aggregation of α-synuclein bound to negatively charged phospholipid small unilamellar vesicles. Through a combination of kinetic and structural studies, we identify key time points in the aggregation process that enable targeted isolation of prefibrillar and early fibrillar intermediates. By using solid-state nuclear magnetic resonance, we show the gradual buildup of structural features in an α-synuclein fibril filament, revealing a segmental folding process. We identify distinct membrane-binding domains in α-synuclein aggregates, and the combined data are used to present a comprehensive mechanism of the folding of α-synuclein on lipid membranes.
Collapse
Affiliation(s)
- Leif Antonschmidt
- Department of NMR-Based Structural Biology, Max-Planck-Institute for Biophysical Chemistry, Göttingen, Germany
| | - Rıza Dervişoğlu
- Department of NMR-Based Structural Biology, Max-Planck-Institute for Biophysical Chemistry, Göttingen, Germany
| | - Vrinda Sant
- Department of NMR-Based Structural Biology, Max-Planck-Institute for Biophysical Chemistry, Göttingen, Germany
- Department of Mechanical and Aerospace Engineering, University of California San Diego, San Diego, CA, USA
| | - Kumar Tekwani Movellan
- Department of NMR-Based Structural Biology, Max-Planck-Institute for Biophysical Chemistry, Göttingen, Germany
| | - Ingo Mey
- Institute of Organic and Biomolecular Chemistry, Georg-August-Universität Göttingen, Göttingen, Germany
| | - Dietmar Riedel
- Laboratory of Electron Microscopy, Max-Planck-Institute for Biophysical Chemistry, Göttingen, Germany
| | - Claudia Steinem
- Institute of Organic and Biomolecular Chemistry, Georg-August-Universität Göttingen, Göttingen, Germany
- Biomolecular Chemistry Group, Max-Planck Institute for Dynamics and Self-Organization, Am Fassberg 17, 37077 Göttingen, Germany
- Cluster of Excellence "Multiscale Bioimaging: From Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany
| | - Stefan Becker
- Department of NMR-Based Structural Biology, Max-Planck-Institute for Biophysical Chemistry, Göttingen, Germany
| | - Loren B Andreas
- Department of NMR-Based Structural Biology, Max-Planck-Institute for Biophysical Chemistry, Göttingen, Germany.
| | - Christian Griesinger
- Department of NMR-Based Structural Biology, Max-Planck-Institute for Biophysical Chemistry, Göttingen, Germany.
- Cluster of Excellence "Multiscale Bioimaging: From Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany
| |
Collapse
|
3
|
Braun T, Stehle J, Kacprzak S, Carl P, Höfer P, Subramaniam V, Drescher M. Intracellular Protein-Lipid Interactions Studied by Rapid-Scan Electron Paramagnetic Resonance Spectroscopy. J Phys Chem Lett 2021; 12:2471-2475. [PMID: 33663214 PMCID: PMC7957861 DOI: 10.1021/acs.jpclett.0c03583] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 02/12/2021] [Indexed: 06/12/2023]
Abstract
Protein-membrane interactions play key roles in essential cellular processes; studying these interactions in the cell is a challenging task of modern biophysical chemistry. A prominent example is the interaction of human α-synuclein (αS) with negatively charged membranes. It has been well-studied in vitro, but in spite of the huge amount of lipid membranes in the crowded environment of biological cells, to date, no interactions have been detected in cells. Here, we use rapid-scan (RS) electron paramagnetic resonance (EPR) spectroscopy to study αS interactions with negatively charged vesicles in vitro and upon transfection of the protein and lipid vesicles into model cells, i.e., oocytes of Xenopus laevis. We show that protein-vesicle interactions are reflected in RS spectra in vitro and in cells, which enables time-resolved monitoring of protein-membrane interaction upon transfection into cells. Our data suggest binding of a small fraction of αS to endogenous membranes.
Collapse
Affiliation(s)
- Theresa
S. Braun
- Department
of Chemistry and Konstanz Research School Chemical Biology, University of Konstanz, 78457 Konstanz, Germany
| | - Juliane Stehle
- Department
of Chemistry and Konstanz Research School Chemical Biology, University of Konstanz, 78457 Konstanz, Germany
| | - Sylwia Kacprzak
- Bruker BioSpin
GmbH, Silberstreifen 4, 76287 Rheinstetten, Germany
| | - Patrick Carl
- Bruker BioSpin
GmbH, Silberstreifen 4, 76287 Rheinstetten, Germany
| | - Peter Höfer
- Bruker BioSpin
GmbH, Silberstreifen 4, 76287 Rheinstetten, Germany
| | - Vinod Subramaniam
- Vrije
Universiteit Amsterdam, De Boelelaan 1105, 1081 HV Amsterdam, The Netherlands
| | - Malte Drescher
- Department
of Chemistry and Konstanz Research School Chemical Biology, University of Konstanz, 78457 Konstanz, Germany
| |
Collapse
|
4
|
Zurlo E, Kumar P, Meisl G, Dear AJ, Mondal D, Claessens MMAE, Knowles TPJ, Huber M. In situ kinetic measurements of α-synuclein aggregation reveal large population of short-lived oligomers. PLoS One 2021; 16:e0245548. [PMID: 33481908 PMCID: PMC7822277 DOI: 10.1371/journal.pone.0245548] [Citation(s) in RCA: 10] [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: 07/17/2020] [Accepted: 01/04/2021] [Indexed: 11/19/2022] Open
Abstract
Knowledge of the mechanisms of assembly of amyloid proteins into aggregates is of central importance in building an understanding of neurodegenerative disease. Given that oligomeric intermediates formed during the aggregation reaction are believed to be the major toxic species, methods to track such intermediates are clearly needed. Here we present a method, electron paramagnetic resonance (EPR), by which the amount of intermediates can be measured over the course of the aggregation, directly in the reacting solution, without the need for separation. We use this approach to investigate the aggregation of α-synuclein (αS), a synaptic protein implicated in Parkinson’s disease and find a large population of oligomeric species. Our results show that these are primary oligomers, formed directly from monomeric species, rather than oligomers formed by secondary nucleation processes, and that they are short-lived, the majority of them dissociates rather than converts to fibrils. As demonstrated here, EPR offers the means to detect such short-lived intermediate species directly in situ. As it relies only on the change in size of the detected species, it will be applicable to a wide range of self-assembling systems, making accessible the kinetics of intermediates and thus allowing the determination of their rates of formation and conversion, key processes in the self-assembly reaction.
Collapse
Affiliation(s)
- Enrico Zurlo
- Department of Physics, Huygens-Kamerlingh Onnes Laboratory, Leiden University, Leiden, The Netherlands
| | - Pravin Kumar
- Department of Physics, Huygens-Kamerlingh Onnes Laboratory, Leiden University, Leiden, The Netherlands
| | - Georg Meisl
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, United Kingdom
| | - Alexander J. Dear
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, United Kingdom
| | - Dipro Mondal
- Department of Physics, Huygens-Kamerlingh Onnes Laboratory, Leiden University, Leiden, The Netherlands
| | | | - Tuomas P. J. Knowles
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, United Kingdom
- Cavendish Laboratory, University of Cambridge, Cambridge, United Kingdom
| | - Martina Huber
- Department of Physics, Huygens-Kamerlingh Onnes Laboratory, Leiden University, Leiden, The Netherlands
- * E-mail:
| |
Collapse
|
5
|
Uluca B, Viennet T, Petrović D, Shaykhalishahi H, Weirich F, Gönülalan A, Strodel B, Etzkorn M, Hoyer W, Heise H. DNP-Enhanced MAS NMR: A Tool to Snapshot Conformational Ensembles of α-Synuclein in Different States. Biophys J 2019; 114:1614-1623. [PMID: 29642031 PMCID: PMC5954275 DOI: 10.1016/j.bpj.2018.02.011] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Revised: 02/04/2018] [Accepted: 02/07/2018] [Indexed: 11/06/2022] Open
Abstract
Intrinsically disordered proteins dynamically sample a wide conformational space and therefore do not adopt a stable and defined three-dimensional conformation. The structural heterogeneity is related to their proper functioning in physiological processes. Knowledge of the conformational ensemble is crucial for a complete comprehension of this kind of proteins. We here present an approach that utilizes dynamic nuclear polarization-enhanced solid-state NMR spectroscopy of sparsely isotope-labeled proteins in frozen solution to take snapshots of the complete structural ensembles by exploiting the inhomogeneously broadened line-shapes. We investigated the intrinsically disordered protein α-synuclein (α-syn), which plays a key role in the etiology of Parkinson’s disease, in three different physiologically relevant states. For the free monomer in frozen solution we could see that the so-called “random coil conformation” consists of α-helical and β-sheet-like conformations, and that secondary chemical shifts of neighboring amino acids tend to be correlated, indicative of frequent formation of secondary structure elements. Based on these results, we could estimate the number of disordered regions in fibrillar α-syn as well as in α-syn bound to membranes in different protein-to-lipid ratios. Our approach thus provides quantitative information on the propensity to sample transient secondary structures in different functional states. Molecular dynamics simulations rationalize the results.
Collapse
Affiliation(s)
- Boran Uluca
- Institute of Complex Systems, Structural Biochemistry, Research Center Jülich, Jülich, Germany; Institute of Physical Biology, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Thibault Viennet
- Institute of Complex Systems, Structural Biochemistry, Research Center Jülich, Jülich, Germany; Institute of Physical Biology, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Dušan Petrović
- Institute of Complex Systems, Structural Biochemistry, Research Center Jülich, Jülich, Germany
| | - Hamed Shaykhalishahi
- Institute of Complex Systems, Structural Biochemistry, Research Center Jülich, Jülich, Germany; Institute of Physical Biology, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Franziska Weirich
- Institute of Complex Systems, Structural Biochemistry, Research Center Jülich, Jülich, Germany; Institute of Physical Biology, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Ayşenur Gönülalan
- Institute of Complex Systems, Structural Biochemistry, Research Center Jülich, Jülich, Germany
| | - Birgit Strodel
- Institute of Complex Systems, Structural Biochemistry, Research Center Jülich, Jülich, Germany; Institute of Theoretical and Computational Chemistry, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Manuel Etzkorn
- Institute of Complex Systems, Structural Biochemistry, Research Center Jülich, Jülich, Germany; Institute of Physical Biology, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Wolfgang Hoyer
- Institute of Complex Systems, Structural Biochemistry, Research Center Jülich, Jülich, Germany; Institute of Physical Biology, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Henrike Heise
- Institute of Complex Systems, Structural Biochemistry, Research Center Jülich, Jülich, Germany; Institute of Physical Biology, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany.
| |
Collapse
|
6
|
Abstract
The past few years have resulted in an increased awareness and recognition of the prevalence and roles of intrinsically disordered proteins and protein regions (IDPs and IDRs, respectively) in synaptic vesicle trafficking and exocytosis and in overall synaptic organization. IDPs and IDRs constitute a class of proteins and protein regions that lack stable tertiary structure, but nevertheless retain biological function. Their significance in processes such as cell signaling is now well accepted, but their pervasiveness and importance in other areas of biology are not as widely appreciated. Here, we review the prevalence and functional roles of IDPs and IDRs associated with the release and recycling of synaptic vesicles at nerve terminals, as well as with the architecture of these terminals. We hope to promote awareness, especially among neuroscientists, of the importance of this class of proteins in these critical pathways and structures. The examples discussed illustrate some of the ways in which the structural flexibility conferred by intrinsic protein disorder can be functionally advantageous in the context of cellular trafficking and synaptic function.
Collapse
Affiliation(s)
- David Snead
- From the Department of Biochemistry, Weill Cornell Medicine, New York, New York 10021
| | - David Eliezer
- From the Department of Biochemistry, Weill Cornell Medicine, New York, New York 10021
| |
Collapse
|
7
|
Choi TS, Han JY, Heo CE, Lee SW, Kim HI. Electrostatic and hydrophobic interactions of lipid-associated α-synuclein: The role of a water-limited interfaces in amyloid fibrillation. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:1854-1862. [DOI: 10.1016/j.bbamem.2018.02.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Revised: 02/05/2018] [Accepted: 02/05/2018] [Indexed: 12/22/2022]
|
8
|
Viennet T, Wördehoff MM, Uluca B, Poojari C, Shaykhalishahi H, Willbold D, Strodel B, Heise H, Buell AK, Hoyer W, Etzkorn M. Structural insights from lipid-bilayer nanodiscs link α-Synuclein membrane-binding modes to amyloid fibril formation. Commun Biol 2018; 1:44. [PMID: 30271927 PMCID: PMC6123806 DOI: 10.1038/s42003-018-0049-z] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Accepted: 03/23/2018] [Indexed: 01/24/2023] Open
Abstract
The protein α-Synuclein (αS) is linked to Parkinson’s disease through its abnormal aggregation, which is thought to involve cytosolic and membrane-bound forms of αS. Following previous studies using micelles and vesicles, we present a comprehensive study of αS interaction with phospholipid bilayer nanodiscs. Using a combination of NMR-spectroscopic, biophysical, and computational methods, we structurally and kinetically characterize αS interaction with different membrane discs in a quantitative and site-resolved way. We obtain global and residue-specific αS membrane affinities, and determine modulations of αS membrane binding due to αS acetylation, membrane plasticity, lipid charge density, and accessible membrane surface area, as well as the consequences of the different binding modes for αS amyloid fibril formation. Our results establish a structural and kinetic link between the observed dissimilar binding modes and either aggregation-inhibiting properties, largely unperturbed aggregation, or accelerated aggregation due to membrane-assisted fibril nucleation. Thibault Viennet and colleagues gain structural insight into amyloid fibril formation from their innovative use of lipid bilayer nanodiscs. This study connects α-Synuclein membrane binding modes to its aggregation properties, furthering our understanding of the cause of neurodegerative diseases.
Collapse
Affiliation(s)
- Thibault Viennet
- Institute of Physical Biology, Heinrich-Heine-University, Universitätsstrasse 1, 40225, Düsseldorf, Germany.,Instititue of Complex Systems (ICS-6), Forschungszentrum Jülich, Wilhelm-Johnen-Strasse, 52428, Jülich, Germany
| | - Michael M Wördehoff
- Institute of Physical Biology, Heinrich-Heine-University, Universitätsstrasse 1, 40225, Düsseldorf, Germany
| | - Boran Uluca
- Institute of Physical Biology, Heinrich-Heine-University, Universitätsstrasse 1, 40225, Düsseldorf, Germany.,Instititue of Complex Systems (ICS-6), Forschungszentrum Jülich, Wilhelm-Johnen-Strasse, 52428, Jülich, Germany
| | - Chetan Poojari
- Instititue of Complex Systems (ICS-6), Forschungszentrum Jülich, Wilhelm-Johnen-Strasse, 52428, Jülich, Germany.,Department of Physics, Tampere University of Technology, Korkeakoulunkatu 10, 33720, Tampere, Finland.,Department of Physics, University of Helsinki, Gustaf Hällströmin katu 2a, 00560, Helsinki, Finland
| | - Hamed Shaykhalishahi
- Institute of Physical Biology, Heinrich-Heine-University, Universitätsstrasse 1, 40225, Düsseldorf, Germany
| | - Dieter Willbold
- Institute of Physical Biology, Heinrich-Heine-University, Universitätsstrasse 1, 40225, Düsseldorf, Germany.,Instititue of Complex Systems (ICS-6), Forschungszentrum Jülich, Wilhelm-Johnen-Strasse, 52428, Jülich, Germany
| | - Birgit Strodel
- Instititue of Complex Systems (ICS-6), Forschungszentrum Jülich, Wilhelm-Johnen-Strasse, 52428, Jülich, Germany
| | - Henrike Heise
- Institute of Physical Biology, Heinrich-Heine-University, Universitätsstrasse 1, 40225, Düsseldorf, Germany.,Instititue of Complex Systems (ICS-6), Forschungszentrum Jülich, Wilhelm-Johnen-Strasse, 52428, Jülich, Germany
| | - Alexander K Buell
- Institute of Physical Biology, Heinrich-Heine-University, Universitätsstrasse 1, 40225, Düsseldorf, Germany
| | - Wolfgang Hoyer
- Institute of Physical Biology, Heinrich-Heine-University, Universitätsstrasse 1, 40225, Düsseldorf, Germany.,Instititue of Complex Systems (ICS-6), Forschungszentrum Jülich, Wilhelm-Johnen-Strasse, 52428, Jülich, Germany
| | - Manuel Etzkorn
- Institute of Physical Biology, Heinrich-Heine-University, Universitätsstrasse 1, 40225, Düsseldorf, Germany. .,Instititue of Complex Systems (ICS-6), Forschungszentrum Jülich, Wilhelm-Johnen-Strasse, 52428, Jülich, Germany.
| |
Collapse
|
9
|
How Do We Study the Dynamic Structure of Unstructured Proteins: A Case Study on Nopp140 as an Example of a Large, Intrinsically Disordered Protein. Int J Mol Sci 2018; 19:ijms19020381. [PMID: 29382046 PMCID: PMC5855603 DOI: 10.3390/ijms19020381] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Revised: 01/22/2018] [Accepted: 01/23/2018] [Indexed: 02/04/2023] Open
Abstract
Intrinsically disordered proteins (IDPs) represent approximately 30% of the human genome and play key roles in cell proliferation and cellular signaling by modulating the function of target proteins via protein-protein interactions. In addition, IDPs are involved in various human disorders, such as cancer, neurodegenerative diseases, and amyloidosis. To understand the underlying molecular mechanism of IDPs, it is important to study their structural features during their interactions with target proteins. However, conventional biochemical and biophysical methods for analyzing proteins, such as X-ray crystallography, have difficulty in characterizing the features of IDPs because they lack an ordered three-dimensional structure. Here, we present biochemical and biophysical studies on nucleolar phosphoprotein 140 (Nopp140), which mostly consists of disordered regions, during its interaction with casein kinase 2 (CK2), which plays a central role in cell growth. Surface plasmon resonance and electron paramagnetic resonance studies were performed to characterize the interaction between Nopp140 and CK2. A single-molecule fluorescence resonance energy transfer study revealed conformational change in Nopp140 during its interaction with CK2. These studies on Nopp140 can provide a good model system for understanding the molecular function of IDPs.
Collapse
|
10
|
Kumar P, Schilderink N, Subramaniam V, Huber M. Membrane Binding of Parkinson's Protein α-Synuclein: Effect of Phosphorylation at Positions 87 and 129 by the S to D Mutation Approach. Isr J Chem 2017; 57:762-770. [PMID: 28919642 PMCID: PMC5573911 DOI: 10.1002/ijch.201600083] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Indexed: 11/10/2022]
Abstract
Human α-synuclein, a protein relevant in the brain with so-far unknown function, plays an important role in Parkinson's disease. The phosphorylation state of αS was related to the disease, prompting interest in this process. The presumed physiological function and the disease action of αS involves membrane interaction. Here, we study the effect of phosphorylation at positions 87 and 129, mimicked by the mutations S87A, S129A (nonphosphorylated) and S87D, S129D (phosphorylated) on membrane binding. Local binding is detected by spin-label continuous-wave electron paramagnetic resonance. For S87A/D, six positions (27, 56, 63, 69, 76, and 90) are probed; and for S129A/D, three (27, 56, and 69). Binding to large unilamellar vesicles of 100 nm diameter of 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-(1'-rac-glycerol) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine in a 1 : 1 composition is not affected by the phosphorylation state of S129. For phosphorylation at S87, local unbinding of αS from the membrane is observed. We speculate that modulating the local membrane affinity by phosphorylation could tune the way αS interacts with different membranes; for example, tuning its membrane fusion activity.
Collapse
Affiliation(s)
- Pravin Kumar
- Department of Physics, Huygens-Kamerlingh-Onnes LaboratoryLeiden UniversityLeidenThe Netherlands
| | - Nathalie Schilderink
- Nanobiophysics, MESA+ Institute for NanotechnologyUniversity of TwenteEnschedeThe Netherlands
| | - Vinod Subramaniam
- Nanobiophysics, MESA+ Institute for NanotechnologyUniversity of TwenteEnschedeThe Netherlands
- FOM Institute AMOLFAmsterdamThe Netherlands
- Vrije Universiteit of AmsterdamAmsterdamThe Netherlands
| | - Martina Huber
- Department of Physics, Huygens-Kamerlingh-Onnes LaboratoryLeiden UniversityLeidenThe Netherlands
| |
Collapse
|
11
|
Robotta M, Cattani J, Martins JC, Subramaniam V, Drescher M. Alpha-Synuclein Disease Mutations Are Structurally Defective and Locally Affect Membrane Binding. J Am Chem Soc 2017; 139:4254-4257. [PMID: 28298083 DOI: 10.1021/jacs.6b05335] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The intrinsically disordered human protein alpha-Synuclein (αS) has a prominent role in Parkinson's disease (PD) pathology. Several familial variants of αS are correlated with inherited PD. Disease mutations have been shown to have an impact on lipid membrane binding. Here, using electron paramagnetic resonance spectroscopy in combination with site-directed spin labeling, we show that familial PD-associated variants are structurally defective in membrane binding and alter the local binding properties of the protein.
Collapse
Affiliation(s)
- Marta Robotta
- Department of Chemistry, Zukunftskolleg, and Konstanz Research School Chemical Biology, University of Konstanz , 78457 Konstanz, Germany
| | - Julia Cattani
- Department of Chemistry, Zukunftskolleg, and Konstanz Research School Chemical Biology, University of Konstanz , 78457 Konstanz, Germany
| | - Juliana Cristina Martins
- Department of Chemistry, Zukunftskolleg, and Konstanz Research School Chemical Biology, University of Konstanz , 78457 Konstanz, Germany.,Department of Physics, State University of Londrina , 86057-970 Londrina, Brazil
| | - Vinod Subramaniam
- Department of Chemistry, Zukunftskolleg, and Konstanz Research School Chemical Biology, University of Konstanz , 78457 Konstanz, Germany.,Vrije Universiteit Amsterdam , De Boelelaan 1105, 1081 HV Amsterdam, The Netherlands
| | - Malte Drescher
- Department of Chemistry, Zukunftskolleg, and Konstanz Research School Chemical Biology, University of Konstanz , 78457 Konstanz, Germany
| |
Collapse
|
12
|
Modulating membrane binding of α-synuclein as a therapeutic strategy. Proc Natl Acad Sci U S A 2017; 114:1223-1225. [PMID: 28126719 DOI: 10.1073/pnas.1620159114] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
|
13
|
Wang C, Zhao C, Li D, Tian Z, Lai Y, Diao J, Liu C. Versatile Structures of α-Synuclein. Front Mol Neurosci 2016; 9:48. [PMID: 27378848 PMCID: PMC4913103 DOI: 10.3389/fnmol.2016.00048] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 06/06/2016] [Indexed: 11/20/2022] Open
Abstract
α-Synuclein (α-syn) is an intrinsically disordered protein abundantly distributed in presynaptic terminals. Aggregation of α-syn into Lewy bodies (LB) is a molecular hallmark of Parkinson’s disease (PD). α-Syn features an extreme conformational diversity, which adapts to different conditions and fulfills versatile functions. However, the molecular mechanism of α-syn transformation and the relation between different structural species and their functional and pathogenic roles in neuronal activities and PD remain unknown. In this mini-review, we summarize the recent discoveries of α-syn structures in the membrane-bound state, in cytosol, and in the amyloid state under physiological and pathological conditions. From the current knowledge on different structural species of α-syn, we intend to find a clue about its function and toxicity in normal neurons and under disease conditions, which could shed light on the PD pathogenesis.
Collapse
Affiliation(s)
- Chuchu Wang
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences Shanghai, China
| | - Chunyu Zhao
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences Shanghai, China
| | - Dan Li
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences Shanghai, China
| | - Zhiqi Tian
- Department of Cancer Biology, College of Medicine, University of CincinnatiCincinnati, OH, USA; Center for Mitochondrial Biology and Medicine, Key Laboratory of Biomedical Information Engineering of Ministry of the Education School of Life Science, Xi'an Jiaotong UniversityXi'an, China
| | - Ying Lai
- Department of Molecular and Cellular Physiology, Stanford University Stanford, CA, USA
| | - Jiajie Diao
- Department of Cancer Biology, College of Medicine, University of Cincinnati Cincinnati, OH, USA
| | - Cong Liu
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences Shanghai, China
| |
Collapse
|
14
|
Kumar P, Segers-Nolten IMJ, Schilderink N, Subramaniam V, Huber M. Parkinson's Protein α-Synuclein Binds Efficiently and with a Novel Conformation to Two Natural Membrane Mimics. PLoS One 2015; 10:e0142795. [PMID: 26588454 PMCID: PMC4654490 DOI: 10.1371/journal.pone.0142795] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Accepted: 10/27/2015] [Indexed: 01/11/2023] Open
Abstract
Binding of human α-Synuclein, a protein associated with Parkinson’s disease, to natural membranes is thought to be crucial in relation to its pathological and physiological function. Here the binding of αS to small unilamellar vesicles mimicking the inner mitochondrial and the neuronal plasma membrane is studied in situ by continuous wave and pulsed electron paramagnetic resonance. Local binding information of αS spin labeled by MTSL at positions 56 and 69 respectively shows that also helix 2 (residues 50–100) binds firmly to both membranes. By double electron-electron resonance (DEER) on the mutant spin labeled at positions 27 and 56 (αS 27/56) a new conformation on the membrane is found with a distance of 3.6 nm/ 3.7 nm between residues 27 and 56. In view of the low negative charge density of these membranes, the strong interaction is surprising, emphasizing that function and pathology of αS could involve synaptic vesicles and mitochondria.
Collapse
Affiliation(s)
- Pravin Kumar
- Department of Physics, Huygens-Kammerlingh-Onnes Laboratory, Leiden University, Leiden, The Netherlands
| | - Ine M. J. Segers-Nolten
- Nanobiophysics, MESA+ Institute for Nanotechnology, University of Twente, Enschede, The Netherlands
| | - Nathalie Schilderink
- Nanobiophysics, MESA+ Institute for Nanotechnology, University of Twente, Enschede, The Netherlands
| | - Vinod Subramaniam
- Nanobiophysics, MESA+ Institute for Nanotechnology, University of Twente, Enschede, The Netherlands
- FOM Institute AMOLF, Amsterdam, The Netherlands
| | - Martina Huber
- Department of Physics, Huygens-Kammerlingh-Onnes Laboratory, Leiden University, Leiden, The Netherlands
- * E-mail:
| |
Collapse
|
15
|
Ysselstein D, Joshi M, Mishra V, Griggs AM, Asiago JM, McCabe GP, Stanciu LA, Post CB, Rochet JC. Effects of impaired membrane interactions on α-synuclein aggregation and neurotoxicity. Neurobiol Dis 2015; 79:150-63. [PMID: 25931201 DOI: 10.1016/j.nbd.2015.04.007] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Revised: 04/20/2015] [Accepted: 04/21/2015] [Indexed: 01/08/2023] Open
Abstract
The post-mortem brains of individuals with Parkinson's disease (PD) and other synucleinopathy disorders are characterized by the presence of aggregated forms of the presynaptic protein α-synuclein (aSyn). Understanding the molecular mechanism of aSyn aggregation is essential for the development of neuroprotective strategies to treat these diseases. In this study, we examined how interactions between aSyn and phospholipid vesicles influence the protein's aggregation and toxicity to dopaminergic neurons. Two-dimensional NMR data revealed that two familial aSyn mutants, A30P and G51D, populated an exposed, membrane-bound conformer in which the central hydrophobic region was dissociated from the bilayer to a greater extent than in the case of wild-type aSyn. A30P and G51D had a greater propensity to undergo membrane-induced aggregation and elicited greater toxicity to primary dopaminergic neurons compared to the wild-type protein. In contrast, the non-familial aSyn mutant A29E exhibited a weak propensity to aggregate in the presence of phospholipid vesicles or to elicit neurotoxicity, despite adopting a relatively exposed membrane-bound conformation. Our findings suggest that the aggregation of exposed, membrane-bound aSyn conformers plays a key role in the protein's neurotoxicity in PD and other synucleinopathy disorders.
Collapse
Affiliation(s)
- Daniel Ysselstein
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN, USA
| | - Mehul Joshi
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN, USA
| | - Vartika Mishra
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN, USA
| | - Amy M Griggs
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN, USA
| | - Josephat M Asiago
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN, USA
| | - George P McCabe
- Department of Statistics, Purdue University, West Lafayette, IN, USA
| | - Lia A Stanciu
- Schools of Materials Engineering and Biomedical Engineering, Purdue University, West Lafayette, IN, USA
| | - Carol Beth Post
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN, USA
| | - Jean-Christophe Rochet
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN, USA.
| |
Collapse
|
16
|
Chui AJ, López CJ, Brooks EK, Chua KC, Doupey TG, Foltz GN, Kamel JG, Larrosa E, Sadiki A, Bridges MD. Multiple structural states exist throughout the helical nucleation sequence of the intrinsically disordered protein stathmin, as reported by electron paramagnetic resonance spectroscopy. Biochemistry 2015; 54:1717-28. [PMID: 25715079 DOI: 10.1021/bi500894q] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The intrinsically disordered protein (IDP) stathmin plays an important regulatory role in cytoskeletal maintenance through its helical binding to tubulin and microtubules. However, it lacks a stable fold in the absence of its binding partner. Although stathmin has been a focus of research over the past two decades, the solution-phase conformational dynamics of this IDP are poorly understood. It has been reported that stathmin is purely monomeric in solution and that it bears a short helical region of persistent foldedness, which may act to nucleate helical folding in the C-terminal direction. Here we report a comprehensive study of the structural equilibria local to this region in stathmin that contradicts these two claims. Using the technique of electron paramagnetic resonance (EPR) spectroscopy on spin-labeled stathmin mutants in the solution-phase and when immobilized on Sepharose solid support, we show that all sites in the helical nucleation region of stathmin exhibit multiple spectral components that correspond to dynamic states of differing mobilities and stabilities. Importantly, a state with relatively low mobility dominates each spectrum with an average population greater than 50%, which we suggest corresponds to an oligomerized state of the protein. This is in contrast to a less populated, more mobile state, which likely represents a helically folded monomeric state of stathmin, and a highly mobile state, which we propose is the random coil conformer of the protein. Our interpretation of the EPR data is confirmed by further characterization of the protein using the techniques of native and SDS PAGE, gel filtration chromatography, and multiangle and dynamic light scattering, all of which show the presence of oligomeric stathmin in solution. Collectively, these data suggest that stathmin exists in a diverse equilibrium of states throughout the purported helical nucleation region and that this IDP exhibits a propensity toward oligomerization.
Collapse
Affiliation(s)
- Ashley J Chui
- Department of Chemistry and Biochemistry, California State University Fullerton , Fullerton, California 92831-6866, United States
| | | | | | | | | | | | | | | | | | | |
Collapse
|
17
|
Snead D, Eliezer D. Alpha-synuclein function and dysfunction on cellular membranes. Exp Neurobiol 2014; 23:292-313. [PMID: 25548530 PMCID: PMC4276801 DOI: 10.5607/en.2014.23.4.292] [Citation(s) in RCA: 155] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Revised: 11/15/2014] [Accepted: 11/16/2014] [Indexed: 11/19/2022] Open
Abstract
Alpha-synuclein is a small neuronal protein that is closely associated with the etiology of Parkinson's disease. Mutations in and alterations in expression levels of alpha-synuclein cause autosomal dominant early onset heredity forms of Parkinson's disease, and sporadic Parkinson's disease is defined in part by the presence of Lewy bodies and Lewy neurites that are composed primarily of alpha-synuclein deposited in an aggregated amyloid fibril state. The normal function of alpha-synuclein is poorly understood, and the precise mechanisms by which it leads to toxicity and cell death are also unclear. Although alpha-synuclein is a highly soluble, cytoplasmic protein, it binds to a variety of cellular membranes of different properties and compositions. These interactions are considered critical for at least some normal functions of alpha-synuclein, and may well play critical roles in both the aggregation of the protein and its mechanisms of toxicity. Here we review the known features of alpha-synuclein membrane interactions in the context of both the putative functions of the protein and of its pathological roles in disease.
Collapse
Affiliation(s)
- David Snead
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065, USA
| | - David Eliezer
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065, USA
| |
Collapse
|
18
|
Fares MB, Ait-Bouziad N, Dikiy I, Mbefo MK, Jovičić A, Kiely A, Holton JL, Lee SJ, Gitler AD, Eliezer D, Lashuel HA. The novel Parkinson's disease linked mutation G51D attenuates in vitro aggregation and membrane binding of α-synuclein, and enhances its secretion and nuclear localization in cells. Hum Mol Genet 2014; 23:4491-509. [PMID: 24728187 DOI: 10.1093/hmg/ddu165] [Citation(s) in RCA: 173] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
A novel mutation in the α-Synuclein (α-Syn) gene "G51D" was recently identified in two familial cases exhibiting features of Parkinson's disease (PD) and multiple system atrophy (MSA). In this study, we explored the impact of this novel mutation on the aggregation, cellular and biophysical properties of α-Syn, in an attempt to unravel how this mutant contributes to PD/MSA. Our results show that the G51D mutation significantly attenuates α-Syn aggregation in vitro. Moreover, it disrupts local helix formation in the presence of SDS, decreases binding to lipid vesicles C-terminal to the site of mutation and severely inhibits helical folding in the presence of acidic vesicles. When expressed in yeast, α-Syn(G51D) behaves similarly to α-Syn(A30P), as both exhibit impaired membrane association, form few inclusions and are non-toxic. In contrast, enhanced secreted and nuclear levels of the G51D mutant were observed in mammalian cells, as well as in primary neurons, where α-Syn(G51D) was enriched in the nuclear compartment, was hyper-phosphorylated at S129 and exacerbated α-Syn-induced mitochondrial fragmentation. Finally, post-mortem human brain tissues of α-Syn(G51D) cases were examined, and revealed only partial colocalization with nuclear membrane markers, probably due to post-mortem tissue delay and fixation. These findings suggest that the PD-linked mutations may cause neurodegeneration via different mechanisms, some of which may be independent of α-Syn aggregation.
Collapse
Affiliation(s)
- Mohamed-Bilal Fares
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, Ecole Polytechnique Fédérale de Lausanne, Station 19, CH-1015 Lausanne, Switzerland
| | - Nadine Ait-Bouziad
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, Ecole Polytechnique Fédérale de Lausanne, Station 19, CH-1015 Lausanne, Switzerland
| | - Igor Dikiy
- Department of Biochemistry and Program in Structural Biology, Weill Cornell Medical College, New York, NY 10065, USA
| | - Martial K Mbefo
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, Ecole Polytechnique Fédérale de Lausanne, Station 19, CH-1015 Lausanne, Switzerland
| | - Ana Jovičić
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Aoife Kiely
- Queen Square Brain Bank, UCL Institute of Neurology, London, UK
| | - Janice L Holton
- Queen Square Brain Bank, UCL Institute of Neurology, London, UK
| | - Seung-Jae Lee
- Department of Biomedical Science and Technology, Konkuk University, Seoul, South Korea
| | - Aaron D Gitler
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - David Eliezer
- Department of Biochemistry and Program in Structural Biology, Weill Cornell Medical College, New York, NY 10065, USA
| | - Hilal A Lashuel
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, Ecole Polytechnique Fédérale de Lausanne, Station 19, CH-1015 Lausanne, Switzerland
| |
Collapse
|
19
|
The N-terminus of α-synuclein is essential for both monomeric and oligomeric interactions with membranes. FEBS Lett 2013; 588:497-502. [DOI: 10.1016/j.febslet.2013.12.015] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Revised: 12/04/2013] [Accepted: 12/13/2013] [Indexed: 11/30/2022]
|
20
|
Dikiy I, Eliezer D. N-terminal acetylation stabilizes N-terminal helicity in lipid- and micelle-bound α-synuclein and increases its affinity for physiological membranes. J Biol Chem 2013; 289:3652-65. [PMID: 24338013 DOI: 10.1074/jbc.m113.512459] [Citation(s) in RCA: 149] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
The Parkinson disease protein α-synuclein is N-terminally acetylated, but most in vitro studies have been performed using unacetylated α-synuclein. Binding to lipid membranes is considered key to the still poorly understood function of α-synuclein. We report the effects of N-terminal acetylation on α-synuclein binding to lipid vesicles of different composition and curvature and to micelles composed of the detergents β-octyl-glucoside (BOG) and SDS. In the presence of SDS, N-terminal acetylation results in a slightly increased helicity for the N-terminal ~10 residues of the protein, likely due to the stabilization of N-terminal fraying through the formation of a helix cap motif. In the presence of BOG, a detergent used in previous isolations of helical oligomeric forms of α-synuclein, the N-terminally acetylated protein adopts a novel conformation in which the N-terminal ~30 residues bind the detergent micelle in a partly helical conformation, whereas the remainder of the protein remains unbound and disordered. Binding of α-synuclein to lipid vesicles with high negative charge content is essentially unaffected by N-terminal acetylation irrespective of curvature, but binding to vesicles of lower negative charge content is increased, with stronger binding observed for vesicles with higher curvature. Thus, the naturally occurring N-terminally acetylated form of α-synuclein exhibits stabilized helicity at its N terminus and increased affinity for lipid vesicles similar to synaptic vesicles, a binding target of the protein in vivo. Furthermore, the novel BOG-bound state of N-terminally acetylated α-synuclein may serve as a model of partly helical membrane-bound intermediates with a role in α-synuclein function and dysfunction.
Collapse
Affiliation(s)
- Igor Dikiy
- From the Department of Biochemistry and Program in Structural Biology, Weill Cornell Medical College, New York, New York 10065
| | | |
Collapse
|
21
|
Varkey J, Mizuno N, Hegde BG, Cheng N, Steven AC, Langen R. α-Synuclein oligomers with broken helical conformation form lipoprotein nanoparticles. J Biol Chem 2013; 288:17620-30. [PMID: 23609437 DOI: 10.1074/jbc.m113.476697] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
α-Synuclein (αS) is a membrane-binding protein with sequence similarity to apolipoproteins and other lipid-carrying proteins, which are capable of forming lipid-containing nanoparticles, sometimes referred to as "discs." Previously, it has been unclear whether αS also possesses this property. Using cryo-electron microscopy and light scattering, we found that αS can remodel phosphatidylglycerol vesicles into nanoparticles whose shape (ellipsoidal) and dimensions (in the 7-10-nm range) resemble those formed by apolipoproteins. The molar ratio of αS to lipid in nanoparticles is ∼1:20, and αS is oligomeric (including trimers and tetramers). Similar nanoparticles form when αS is added to vesicles of mitochondrial lipids. This observation suggests a mechanism for the previously reported disruption of mitochondrial membranes by αS. Circular dichroism and four-pulse double electron electron resonance experiments revealed that in nanoparticles αS assumes a broken helical conformation distinct from the extended helical conformation adopted when αS is bound to intact vesicles or membrane tubules. We also observed αS-dependent tubule and nanoparticle formation in the presence of oleic acid, implying that αS can interact with fatty acids and lipids in a similar manner. αS-related nanoparticles might play a role in lipid and fatty acid transport functions previously attributed to this protein.
Collapse
Affiliation(s)
- Jobin Varkey
- Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, California 90033, USA
| | | | | | | | | | | |
Collapse
|
22
|
Solid-state ¹³C NMR reveals annealing of raft-like membranes containing cholesterol by the intrinsically disordered protein α-Synuclein. J Mol Biol 2013; 425:2973-87. [PMID: 23583776 DOI: 10.1016/j.jmb.2013.04.002] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2012] [Revised: 03/14/2013] [Accepted: 04/02/2013] [Indexed: 11/20/2022]
Abstract
Misfolding and aggregation of the intrinsically disordered protein α-Synuclein (αS) in Lewy body plaques are characteristic markers of late-stage Parkinson's disease. It is well established that membrane binding is initiated at the N-terminus of the protein and affects biasing of conformational ensembles of αS. However, little is understood about the effect of αS on the membrane lipid bilayer. One hypothesis is that intrinsically disordered αS alters the structural properties of the membrane, thereby stabilizing the bilayer against fusion. Here, we used two-dimensional (13)C separated local-field NMR to study interaction of the wild-type α-Synuclein (wt-αS) or its N-terminal (1-25) amino acid sequence (N-αS) with a cholesterol-enriched ternary membrane system. This lipid bilayer mimics cellular raft-like domains in the brain that are proposed to be involved in neuronal membrane fusion. The two-dimensional dipolar-recoupling pulse sequence DROSS (dipolar recoupling on-axis with scaling and shape preservation) was implemented to measure isotropic (13)C chemical shifts and (13)C-(1)H residual dipolar couplings under magic-angle spinning. Site-specific changes in NMR chemical shifts and segmental order parameters indicate that both wt-αS and N-αS bind to the membrane interface and change lipid packing within raft-like membranes. Mean-torque modeling of (13)C-(1)H NMR order parameters shows that αS induces a remarkable thinning of the bilayer (≈6Å), accompanied by an increase in phospholipid cross-sectional area (≈10Å(2)). This perturbation is characterized as membrane annealing and entails structural remodeling of the raft-like liquid-ordered phase. We propose this process is implicated in regulation of synaptic membrane fusion that may be altered by aggregation of αS in Parkinson's disease.
Collapse
|
23
|
Alderson TR, Markley JL. Biophysical characterization of α-synuclein and its controversial structure. INTRINSICALLY DISORDERED PROTEINS 2013; 1:18-39. [PMID: 24634806 PMCID: PMC3908606 DOI: 10.4161/idp.26255] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Accepted: 08/23/2013] [Indexed: 12/16/2022]
Abstract
α-synuclein, a presynaptic protein of poorly defined function, constitutes the main component of Parkinson disease-associated Lewy bodies. Extensive biophysical investigations have provided evidence that isolated α-synuclein is an intrinsically disordered protein (IDP) in vitro. Subsequently serving as a model IDP in numerous studies, α-synuclein has aided in the development of many technologies used to characterize IDPs and arguably represents the most thoroughly analyzed IDP to date. Recent reports, however, have challenged the disordered nature of α-synuclein inside cells and have instead proposed a physiologically relevant helical tetramer. Despite α-synuclein's rich biophysical history, a single coherent picture has not yet emerged concerning its in vivo structure, dynamics, and physiological role(s). We present herein a review of the biophysical discoveries, developments, and models pertinent to the characterization of α-synuclein's structure and analysis of the native tetramer controversy.
Collapse
Affiliation(s)
- T Reid Alderson
- Biochemistry Department; University of Wisconsin-Madison; Madison, WI USA
| | - John L Markley
- Biochemistry Department; University of Wisconsin-Madison; Madison, WI USA ; National Magnetic Resonance Facility at Madison; University of Wisconsin-Madison; Madison, WI USA
| |
Collapse
|
24
|
Caruana M, Neuner J, Högen T, Schmidt F, Kamp F, Scerri C, Giese A, Vassallo N. Polyphenolic compounds are novel protective agents against lipid membrane damage by α-synuclein aggregates in vitro. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1818:2502-10. [DOI: 10.1016/j.bbamem.2012.05.019] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Revised: 05/11/2012] [Accepted: 05/15/2012] [Indexed: 01/18/2023]
|
25
|
Burré J, Sharma M, Südhof TC. Systematic mutagenesis of α-synuclein reveals distinct sequence requirements for physiological and pathological activities. J Neurosci 2012; 32:15227-42. [PMID: 23100443 PMCID: PMC3506191 DOI: 10.1523/jneurosci.3545-12.2012] [Citation(s) in RCA: 125] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Revised: 08/20/2012] [Accepted: 09/02/2012] [Indexed: 12/22/2022] Open
Abstract
α-Synuclein is an abundant presynaptic protein that binds to phospholipids and synaptic vesicles. Physiologically, α-synuclein functions as a SNARE-protein chaperone that promotes SNARE-complex assembly for neurotransmitter release. Pathologically, α-synuclein mutations and α-synuclein overexpression cause Parkinson's disease, and aggregates of α-synuclein are found as Lewy bodies in multiple neurodegenerative disorders ("synucleinopathies"). The relation of the physiological functions to the pathological effects of α-synuclein remains unclear. As an initial avenue of addressing this question, we here systematically examined the effect of α-synuclein mutations on its physiological and pathological activities. We generated 26 α-synuclein mutants spanning the entire molecule, and analyzed them compared with wild-type α-synuclein in seven assays that range from biochemical studies with purified α-synuclein, to analyses of α-synuclein expression in cultured neurons, to examinations of the effects of virally expressed α-synuclein introduced into the mouse substantia nigra by stereotactic injections. We found that both the N-terminal and C-terminal sequences of α-synuclein were required for its physiological function as SNARE-complex chaperone, but that these sequences were not essential for its neuropathological effects. In contrast, point mutations in the central region of α-synuclein, referred to as nonamyloid β component (residues 61-95), as well as point mutations linked to Parkinson's disease (A30P, E46K, and A53T) increased the neurotoxicity of α-synuclein but did not affect its physiological function in SNARE-complex assembly. Thus, our data show that the physiological function of α-synuclein, although protective of neurodegeneration in some contexts, is fundamentally distinct from its neuropathological effects, thereby dissociating the two activities of α-synuclein.
Collapse
Affiliation(s)
- Jacqueline Burré
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, California 94305-5453, and
| | - Manu Sharma
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, California 94305-5453, and
| | - Thomas C. Südhof
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, California 94305-5453, and
- Howard Hughes Medical Institute, Stanford University, Stanford, California 94305-5453
| |
Collapse
|
26
|
Mizuno N, Varkey J, Kegulian NC, Hegde BG, Cheng N, Langen R, Steven AC. Remodeling of lipid vesicles into cylindrical micelles by α-synuclein in an extended α-helical conformation. J Biol Chem 2012; 287:29301-11. [PMID: 22767608 DOI: 10.1074/jbc.m112.365817] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
α-Synuclein (αS) is a protein with multiple conformations and interactions. Natively unfolded in solution, αS accumulates as amyloid in neurological tissue in Parkinson disease and interacts with membranes under both physiological and pathological conditions. Here, we used cryoelectron microscopy in conjunction with electron paramagnetic resonance (EPR) and other techniques to characterize the ability of αS to remodel vesicles. At molar ratios of 1:5 to 1:40 for protein/lipid (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoglycerol), large spherical vesicles are converted into cylindrical micelles ~50 Å in diameter. Other lipids of the same charge (negative) exhibit generally similar behavior, although bilayer tubes of 150-500 Å in width are also produced, depending on the lipid acyl chains. At higher protein/lipid ratios, discoid particles, 70-100 Å across, are formed. EPR data show that, on cylindrical micelles, αS adopts an extended amphipathic α-helical conformation, with its long axis aligned with the tube axis. The observed geometrical relationship between αS and the micelle suggests that the wedging of its long α-helix into the outer leaflet of a membrane may cause curvature and an anisotropic partition of lipids, leading to tube formation.
Collapse
Affiliation(s)
- Naoko Mizuno
- Laboratory of Structural Biology, NIAMS, National Institutes of Health, Bethesda, MD 20892, USA.
| | | | | | | | | | | | | |
Collapse
|
27
|
|
28
|
Robotta M, Hintze C, Schildknecht S, Zijlstra N, Jüngst C, Karreman C, Huber M, Leist M, Subramaniam V, Drescher M. Locally Resolved Membrane Binding Affinity of the N-Terminus of α-Synuclein. Biochemistry 2012; 51:3960-2. [DOI: 10.1021/bi300357a] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Marta Robotta
- Departments of Chemistry and
Biology, Konstanz Research School Chemical Biology, and Zukunftskolleg, University of Konstanz, 78457 Konstanz, Germany
| | - Christian Hintze
- Departments of Chemistry and
Biology, Konstanz Research School Chemical Biology, and Zukunftskolleg, University of Konstanz, 78457 Konstanz, Germany
| | - Stefan Schildknecht
- Departments of Chemistry and
Biology, Konstanz Research School Chemical Biology, and Zukunftskolleg, University of Konstanz, 78457 Konstanz, Germany
| | - Niels Zijlstra
- Nanobiophysics,
MESA+ Institute
for Nanotechnology and MIRA Institute for Biomedical Technology and
Technical Medicine, University of Twente, 7500 AE Enschede, The Netherlands
| | - Christian Jüngst
- Departments of Chemistry and
Biology, Konstanz Research School Chemical Biology, and Zukunftskolleg, University of Konstanz, 78457 Konstanz, Germany
| | - Christiaan Karreman
- Departments of Chemistry and
Biology, Konstanz Research School Chemical Biology, and Zukunftskolleg, University of Konstanz, 78457 Konstanz, Germany
| | - Martina Huber
- Leiden Institute of Physics, University of Leiden, P.O. Box 9504, 2300 RA Leiden,
The Netherlands
| | - Marcel Leist
- Departments of Chemistry and
Biology, Konstanz Research School Chemical Biology, and Zukunftskolleg, University of Konstanz, 78457 Konstanz, Germany
| | - Vinod Subramaniam
- Departments of Chemistry and
Biology, Konstanz Research School Chemical Biology, and Zukunftskolleg, University of Konstanz, 78457 Konstanz, Germany
- Nanobiophysics,
MESA+ Institute
for Nanotechnology and MIRA Institute for Biomedical Technology and
Technical Medicine, University of Twente, 7500 AE Enschede, The Netherlands
| | - Malte Drescher
- Departments of Chemistry and
Biology, Konstanz Research School Chemical Biology, and Zukunftskolleg, University of Konstanz, 78457 Konstanz, Germany
| |
Collapse
|
29
|
Tian J, Sethi A, Anunciado D, Vu DM, Gnanakaran S. Characterization of a disordered protein during micellation: interactions of α-synuclein with sodium dodecyl sulfate. J Phys Chem B 2012; 116:4417-24. [PMID: 22439820 PMCID: PMC3357070 DOI: 10.1021/jp210339f] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
To better understand the interaction of α-synuclein (αSyn) with lipid membranes, we carried out self-assembly molecular dynamics simulations of αSyn with monomeric and micellar sodium dodecyl sulfate (SDS), a widely used membrane mimic. We find that both electrostatic and hydrophobic forces contribute to the interactions of αSyn with SDS. In the presence of αSyn, our simulations suggest that SDS aggregates along the protein chain and forms small-size micelles at very early times. Aggregation is followed by formation of a collapsed protein-SDS micelle complex, which is consistent with experimental results. Finally, interaction of αSyn with preformed micelles induces alterations in the shape of the micelle, and the N-terminal helix (residues 3 through 37) tends to associate with micelles. Overall, our simulations provide an atomistic description of the early time scale αSyn-SDS interaction during the self-assembly of SDS into micelles.
Collapse
Affiliation(s)
- Jianhui Tian
- Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos 87545
| | - Anurag Sethi
- Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos 87545
| | - Divina Anunciado
- Physical Chemistry & Applied Spectroscopy, Los Alamos National Laboratory, Los Alamos 87545
| | - Dung M. Vu
- Physical Chemistry & Applied Spectroscopy, Los Alamos National Laboratory, Los Alamos 87545
| | - S. Gnanakaran
- Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos 87545
| |
Collapse
|
30
|
Högen T, Levin J, Schmidt F, Caruana M, Vassallo N, Kretzschmar H, Bötzel K, Kamp F, Giese A. Two different binding modes of α-synuclein to lipid vesicles depending on its aggregation state. Biophys J 2012; 102:1646-55. [PMID: 22500765 DOI: 10.1016/j.bpj.2012.01.059] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2011] [Revised: 12/05/2011] [Accepted: 01/30/2012] [Indexed: 12/13/2022] Open
Abstract
Aggregation of α-synuclein is involved in the pathogenesis of Parkinson's disease (PD). Studies of in vitro aggregation of α-synuclein are rendered complex because of the formation of a heterogeneous population of oligomers. With the use of confocal single-molecule fluorescence techniques, we demonstrate that small aggregates (oligomers) of α-synuclein formed from unbound monomeric species in the presence of organic solvent (DMSO) and iron (Fe(3+)) ions have a high affinity to bind to model membranes, regardless of the lipid-composition or membrane curvature. This binding mode contrasts with the well-established membrane binding of α-synuclein monomers, which is accompanied with α-helix formation and requires membranes with high curvature, defects in the lipid packing, and/or negatively charged lipids. Additionally, we demonstrate that membrane-bound α-synuclein monomers are protected from aggregation. Finally, we identified compounds that potently dissolved vesicle-bound α-synuclein oligomers into monomers, leaving the lipid vesicles intact. As it is commonly believed that formation of oligomers is related PD progression, such compounds may provide a promising strategy for the design of novel therapeutic drugs in Parkinson's disease.
Collapse
Affiliation(s)
- Tobias Högen
- Neurologische Klinik, Klinikum Großhadern, Ludwig-Maximilians-Universität, Munich, Germany
| | | | | | | | | | | | | | | | | |
Collapse
|
31
|
Drescher M, Huber M, Subramaniam V. Hunting the Chameleon: Structural Conformations of the Intrinsically Disordered Protein Alpha-Synuclein. Chembiochem 2012; 13:761-8. [DOI: 10.1002/cbic.201200059] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Indexed: 12/14/2022]
|
32
|
Vlad C, Lindner K, Karreman C, Schildknecht S, Leist M, Tomczyk N, Rontree J, Langridge J, Danzer K, Ciossek T, Petre A, Gross ML, Hengerer B, Przybylski M. Autoproteolytic fragments are intermediates in the oligomerization/aggregation of the Parkinson's disease protein alpha-synuclein as revealed by ion mobility mass spectrometry. Chembiochem 2011; 12:2740-4. [PMID: 22162214 DOI: 10.1002/cbic.201100569] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2011] [Indexed: 12/29/2022]
Abstract
Gas-phase protein separation by ion mobility: With its ability to separate the Parkinson's disease protein α-synuclein and its autoproteolytic products-despite the small concentrations of the latter-ion-mobility MS has enabled the characterization of intermediate fragments in in vitro oligomerization-aggregation. In particular, a possible key fragment, the highly aggregating C-terminal fragment, αSyn(72-140), has been revealed.
Collapse
Affiliation(s)
- Camelia Vlad
- Department of Chemistry, University of Konstanz, 78457 Konstanz, Germany
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
33
|
Shvadchak VV, Yushchenko DA, Pievo R, Jovin TM. The mode of α-synuclein binding to membranes depends on lipid composition and lipid to protein ratio. FEBS Lett 2011; 585:3513-9. [PMID: 22004764 DOI: 10.1016/j.febslet.2011.10.006] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2011] [Revised: 10/01/2011] [Accepted: 10/03/2011] [Indexed: 11/28/2022]
Abstract
Interactions of the presynaptic protein α-synuclein with membranes are involved in its physiological action as well as in the pathological misfolding and aggregation related to Parkinsons's disease. We studied the conformation and orientation of α-synuclein bound to model vesicular membranes using multiparametric response polarity-sensitive fluorescent probes together with CD and EPR measurements. At low lipid to α-synuclein ratio the protein binds membranes through its N-terminal domain. When lipids are in excess, the α-helical content and the role of the C-terminus in binding increase. Highly rigid membranes also induce a greater α-helical content and a lower polarity of the protein microenvironment.
Collapse
Affiliation(s)
- Volodymyr V Shvadchak
- Laboratory of Cellular Dynamics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.
| | | | | | | |
Collapse
|
34
|
Dikiy I, Eliezer D. Folding and misfolding of alpha-synuclein on membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1818:1013-8. [PMID: 21945884 DOI: 10.1016/j.bbamem.2011.09.008] [Citation(s) in RCA: 146] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2011] [Revised: 09/09/2011] [Accepted: 09/12/2011] [Indexed: 12/23/2022]
Abstract
The protein alpha-synuclein is considered to play a major role in the etiology of Parkinson's disease. Because it is found in a classic amyloid fibril form within the characteristic intra-neuronal Lewy body deposits of the disease, aggregation of the protein is thought to be of critical importance, but the context in which the protein undergoes aggregation within cells remains unknown. The normal function of synucleins is poorly understood, but appears to involve membrane interactions, and in particular reversible binding to synaptic vesicle membranes. Structural studies of different states of alpha-synuclein, in the absence and presence of membranes or membrane mimetics, have led to models of how membrane-bound forms of the protein may contribute both to functional properties of the protein, as well as to membrane-induced self-assembly and aggregation. This article reviews this area, with a focus on a particular model that has emerged in the past few years. This article is part of a Special Issue entitled: Protein Folding in Membranes.
Collapse
Affiliation(s)
- Igor Dikiy
- Department of Biochemistry and Program in Structural Biology, Weill Cornell Medical College, New York, NY 10065, USA
| | | |
Collapse
|
35
|
Sevcsik E, Trexler AJ, Dunn JM, Rhoades E. Allostery in a disordered protein: oxidative modifications to α-synuclein act distally to regulate membrane binding. J Am Chem Soc 2011; 133:7152-8. [PMID: 21491910 DOI: 10.1021/ja2009554] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Both oxidative stress and aggregation of the protein α-synuclein (aS) have been implicated as key factors in the etiology of Parkinson's disease. Specifically, oxidative modifications to aS disrupt its binding to lipid membranes, an interaction considered critical to its native function. Here we seek to provide a mechanistic explanation for this phenomenon by investigating the effects of oxidative nitration of tyrosine residues on the structure of aS and its interaction with lipid membranes. Membrane binding is mediated by the first ∼95 residues of aS. We find that nitration of the single tyrosine (Y39) in this domain disrupts binding due to electrostatic repulsion. Moreover, we observe that nitration of the three tyrosines (Y125/133/136) in the C-terminal domain is equally effective in perturbing binding, an intriguing result given that the C-terminus is not thought to interact directly with the lipid bilayer. Our investigations show that tyrosine nitration results in a change of the conformational states populated by aS in solution, with the most prominent changes occurring in the C-terminal region. These results lead us to suggest that nitration of Y125/133/136 reduces the membrane-binding affinity of aS through allosteric coupling by altering the ensemble of conformational states and depopulating those capable of membrane binding. While allostery is a well-established concept for structured proteins, it has only recently been discussed in the context of disordered proteins. We propose that allosteric regulation through modification of specific residues in, or ligand binding to, the C-terminus may even be a general mechanism for modulating aS function.
Collapse
Affiliation(s)
- Eva Sevcsik
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06511, USA
| | | | | | | |
Collapse
|
36
|
Wang GF, Li C, Pielak GJ. 19F NMR studies of α-synuclein-membrane interactions. Protein Sci 2011; 19:1686-91. [PMID: 20629174 DOI: 10.1002/pro.449] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
α-Synuclein function is thought to be related to its membrane binding ability. Solution NMR studies have identified several α-synuclein-membrane interaction modes in small unilamellar vesicles (SUVs), but how membrane properties affect binding remains unclear. Here, we use (19)F NMR to study α-synuclein-membrane interactions by using 3-fluoro-L-tyrosine (3FY) and trifluoromethyl-L-phenylalanine (tfmF) labeled proteins. Our results indicate that the affinity is affected by both the head group and the acyl chain of the SUV. Negatively charged head groups have higher affinity, but different head groups with the same charge also affect binding. We show that the saturation of the acyl chain has a dramatic effect on the α-synuclein-membrane interactions by studying lipids with the same head group but different chains. Taken together, the data show that α-synuclein's N-terminal region is the most important determinate of SUV binding, but its C-terminal region also modulates the interactions. Our data support the existence of multiple tight phospholipid-binding modes, a result incompatible with the model that α-synuclein lies solely on the membrane surface.
Collapse
Affiliation(s)
- Gui-Fang Wang
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | | | | |
Collapse
|
37
|
Shvadchak VV, Falomir-Lockhart LJ, Yushchenko DA, Jovin TM. Specificity and kinetics of alpha-synuclein binding to model membranes determined with fluorescent excited state intramolecular proton transfer (ESIPT) probe. J Biol Chem 2011; 286:13023-32. [PMID: 21330368 DOI: 10.1074/jbc.m110.204776] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Parkinson disease is characterized cytopathologically by the deposition in the midbrain of aggregates composed primarily of the presynaptic neuronal protein α-synuclein (AS). Neurotoxicity is currently attributed to oligomeric microaggregates subjected to oxidative modification and promoting mitochondrial and proteasomal dysfunction. Unphysiological binding to membranes of these and other organelles is presumably involved. In this study, we performed a systematic determination of the influence of charge, phase, curvature, defects, and lipid unsaturation on AS binding to model membranes using a new sensitive solvatochromic fluorescent probe. The interaction of AS with vesicular membranes is fast and reversible. The protein dissociates from neutral membranes upon thermal transition to the liquid disordered phase and transfers to vesicles with higher affinity. The binding of AS to neutral and negatively charged membranes occurs by apparently different mechanisms. Interaction with neutral bilayers requires the presence of membrane defects; binding increases with membrane curvature and rigidity and decreases in the presence of cholesterol. The association with negatively charged membranes is much stronger and much less sensitive to membrane curvature, phase, and cholesterol content. The presence of unsaturated lipids increases binding in all cases. These findings provide insight into the relation between membrane physical properties and AS binding affinity and dynamics that presumably define protein localization in vivo and, thereby, the role of AS in the physiopathology of Parkinson disease.
Collapse
Affiliation(s)
- Volodymyr V Shvadchak
- Laboratory of Cellular Dynamics, Max Planck Institute for Biophysical Chemistry, am Fassberg 11, 37077 Göttingen, Germany
| | | | | | | |
Collapse
|
38
|
Butterfield SM, Lashuel HA. Amyloidogenic protein-membrane interactions: mechanistic insight from model systems. Angew Chem Int Ed Engl 2011; 49:5628-54. [PMID: 20623810 DOI: 10.1002/anie.200906670] [Citation(s) in RCA: 474] [Impact Index Per Article: 36.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The toxicity of amyloid-forming proteins is correlated with their interactions with cell membranes. Binding events between amyloidogenic proteins and membranes result in mutually disruptive structural perturbations, which are associated with toxicity. Membrane surfaces promote the conversion of amyloid-forming proteins into toxic aggregates, and amyloidogenic proteins, in turn, compromise the structural integrity of the cell membrane. Recent studies with artificial model membranes have highlighted the striking resemblance of the mechanisms of membrane permeabilization of amyloid-forming proteins to those of pore-forming toxins and antimicrobial peptides.
Collapse
Affiliation(s)
- Sara M Butterfield
- Laboratory of Molecular Neurobiology and Neuroproteomics, Swiss Federal Institute of Technology Lausanne (EPFL), SV-BMI-LMNN AI2351, 1015 Lausanne, Switzerland
| | | |
Collapse
|
39
|
Abstract
Intrinsically disordered proteins (IDPs) form a unique protein category characterized by the absence of a well-defined structure and by remarkable conformational flexibility. Electron Paramagnetic Resonance (EPR) spectroscopy combined with site-directed spin labeling (SDSL) is amongst the most suitable methods to unravel their structure and dynamics. This review summarizes the tremendous methodological developments in the area of SDSL EPR and its applications in protein research. Recent results on the intrinsically disordered Parkinson's disease protein α-synuclein illustrate that the method has gained increasing attention in IDP research. SDSL EPR has now reached a level where broad application in this rapidly advancing field is feasible.
Collapse
Affiliation(s)
- Malte Drescher
- Department of Chemistry, University of Konstanz, Konstanz, Germany.
| |
Collapse
|
40
|
Moore B, Miles AJ, Guerra-Giraldez C, Simpson P, Iwata M, Wallace BA, Matthews SJ, Smith DF, Brown KA. Structural basis of molecular recognition of the Leishmania small hydrophilic endoplasmic reticulum-associated protein (SHERP) at membrane surfaces. J Biol Chem 2010; 286:9246-56. [PMID: 21106528 PMCID: PMC3059043 DOI: 10.1074/jbc.m110.130427] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The 57-residue small hydrophilic endoplasmic reticulum-associated protein (SHERP) shows highly specific, stage-regulated expression in the non-replicative vector-transmitted stages of the kinetoplastid parasite, Leishmania major, the causative agent of human cutaneous leishmaniasis. Previous studies have demonstrated that SHERP localizes as a peripheral membrane protein on the cytosolic face of the endoplasmic reticulum and on outer mitochondrial membranes, whereas its high copy number suggests a critical function in vivo. However, the absence of defined domains or identifiable orthologues, together with lack of a clear phenotype in transgenic parasites lacking SHERP, has limited functional understanding of this protein. Here, we use a combination of biophysical and biochemical methods to demonstrate that SHERP can be induced to adopt a globular fold in the presence of anionic lipids or SDS. Cross-linking and binding studies suggest that SHERP has the potential to form a complex with the vacuolar type H(+)-ATPase. Taken together, these results suggest that SHERP may function in modulating cellular processes related to membrane organization and/or acidification during vector transmission of infective Leishmania.
Collapse
Affiliation(s)
- Benjamin Moore
- Division of Cell and Molecular Biology, Centre for Molecular Microbiology and Infection, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom
| | | | | | | | | | | | | | | | | |
Collapse
|
41
|
Identification of a helical intermediate in trifluoroethanol-induced alpha-synuclein aggregation. Proc Natl Acad Sci U S A 2010; 107:18850-5. [PMID: 20947801 DOI: 10.1073/pnas.1012336107] [Citation(s) in RCA: 147] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Because oligomers and aggregates of the protein α-synuclein (αS) are implicated in the initiation and progression of Parkinson's disease, investigation of various αS aggregation pathways and intermediates aims to clarify the etiology of this common neurodegenerative disorder. Here, we report the formation of short, flexible, β-sheet-rich fibrillar species by incubation of αS in the presence of intermediate (10-20% v/v) concentrations of 2,2,2-trifluoroethanol (TFE). We find that efficient production of these TFE fibrils is strongly correlated with the TFE-induced formation of a monomeric, partly helical intermediate conformation of αS, which exists in equilibrium with the natively disordered state at low [TFE] and with a highly α-helical conformation at high [TFE]. This partially helical intermediate is on-pathway to the TFE-induced formation of both the highly helical monomeric conformation and the fibrillar species. TFE-induced conformational changes in the monomer protein are similar for wild-type αS and the C-terminal truncation mutant αS1-102, indicating that TFE-induced structural transitions involve the N terminus of the protein. Moreover, the secondary structural transitions of three Parkinson's disease-associated mutants, A30P, A53T, and E46K, are nearly identical to wild-type αS, but oligomerization rates differ substantially among the mutants. Our results add to a growing body of evidence indicating the involvement of helical intermediates in protein aggregation processes. Given that αS is known to populate both highly and partially helical states upon association with membranes, these TFE-induced conformations imply relevant pathways for membrane-induced αS aggregation both in vitro and in vivo.
Collapse
|
42
|
Inhibition of mitochondrial fusion by α-synuclein is rescued by PINK1, Parkin and DJ-1. EMBO J 2010; 29:3571-89. [PMID: 20842103 DOI: 10.1038/emboj.2010.223] [Citation(s) in RCA: 370] [Impact Index Per Article: 26.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2010] [Accepted: 08/12/2010] [Indexed: 11/09/2022] Open
Abstract
Aggregation of α-synuclein (αS) is involved in the pathogenesis of Parkinson's disease (PD) and a variety of related neurodegenerative disorders. The physiological function of αS is largely unknown. We demonstrate with in vitro vesicle fusion experiments that αS has an inhibitory function on membrane fusion. Upon increased expression in cultured cells and in Caenorhabditis elegans, αS binds to mitochondria and leads to mitochondrial fragmentation. In C. elegans age-dependent fragmentation of mitochondria is enhanced and shifted to an earlier time point upon expression of exogenous αS. In contrast, siRNA-mediated downregulation of αS results in elongated mitochondria in cell culture. αS can act independently of mitochondrial fusion and fission proteins in shifting the dynamic morphologic equilibrium of mitochondria towards reduced fusion. Upon cellular fusion, αS prevents fusion of differently labelled mitochondrial populations. Thus, αS inhibits fusion due to its unique membrane interaction. Finally, mitochondrial fragmentation induced by expression of αS is rescued by coexpression of PINK1, parkin or DJ-1 but not the PD-associated mutations PINK1 G309D and parkin Δ1-79 or by DJ-1 C106A.
Collapse
|
43
|
Butterfield S, Lashuel H. Wechselwirkungen zwischen amyloidogenen Proteinen und Membranen: Modellsysteme liefern mechanistische Einblicke. Angew Chem Int Ed Engl 2010. [DOI: 10.1002/ange.200906670] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
|
44
|
Georgieva ER, Ramlall TF, Borbat PP, Freed JH, Eliezer D. The lipid-binding domain of wild type and mutant alpha-synuclein: compactness and interconversion between the broken and extended helix forms. J Biol Chem 2010; 285:28261-74. [PMID: 20592036 DOI: 10.1074/jbc.m110.157214] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Alpha-synuclein (alphaS) is linked to Parkinson disease through its deposition in an amyloid fibril form within Lewy Body deposits, and by the existence of three alphaS point mutations that lead to early onset autosomal dominant Parkinsonism. The normal function of alphaS is thought to be linked to the ability of the protein to bind to the surface of synaptic vesicles. Upon binding to vesicles, alphaS undergoes a structural reorganization from a dynamic and disordered ensemble to a conformation consisting of a long extended helix. In the presence of small spheroidal detergent micelles, however, this extended helix conformation can convert into a broken helix state, in which a region near the middle of the helix unwinds to form a linker between the two resulting separated helices. Membrane-bound conformations of alphaS likely mediate the function of the protein, but may also play a role in the aggregation and toxicity of the protein. Here we have undertaken a study of the effects of the three known PD-linked mutations on the detergent- and membrane-bound conformations of alphaS, as well as factors that govern the transition of the protein between the extended helix and broken helix states. Using pulsed dipolar ESR measurements of distances up to 8.7 nm, we show that all three PD-linked alphaS mutants retain the ability to transition from the broken helix to the extended helix conformation. In addition, we find that the ratio of protein to detergent, rather than just the absolute detergent concentration, determines whether the protein adopts the broken or extended helix conformation.
Collapse
Affiliation(s)
- Elka R Georgieva
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, USA
| | | | | | | | | |
Collapse
|
45
|
Wang X, Moualla D, Wright JA, Brown DR. Copper binding regulates intracellular alpha-synuclein localisation, aggregation and toxicity. J Neurochem 2010; 113:704-14. [PMID: 20141569 DOI: 10.1111/j.1471-4159.2010.06638.x] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Alpha-synuclein is a natively unfolded protein that aggregates and forms inclusions that are associated with a range of diseases that include Parkinson's Disease and Dementia with Lewy Bodies. The mechanism behind the formation of these inclusions and their possible role in disease remains unclear. Alpha-synuclein has also been shown to bind metals including copper and iron. We used a cell culture model of alpha-synuclein aggregation to examine the relationship between metals and formation of aggregates of the protein. While the levels of iron appear to have no role in aggregate formation or localisation of the protein in cells, copper appears to be important for both aggregation and cellular localisation of alpha-synuclein. Reduction in cellular copper resulted in a great decrease in aggregate formation both in terms of large aggregates visible in cells and oligomers observed in western blot analysis of cell extracts. Reduction in copper also resulted in a change in localisation of the protein which became more intensely localised to the plasma membrane in medium with low copper. These changes were reversed when copper was restored to the cells. Mutants of the copper binding domains altered the response to copper. Deletion of either the N- or C-termini resulted in a loss of aggregation while deletion of the C-termini also resulted in a loss of membrane association. Increased expression of alpha-synuclein also increased cell sensitivity to the toxicity of copper. These results suggest that the potential pathological role of alpha-synuclein aggregates is dependent upon the copper binding capacity of the protein.
Collapse
Affiliation(s)
- Xiaoyan Wang
- Department of Biology and Biochemistry, University of Bath, Bath, UK
| | | | | | | |
Collapse
|
46
|
Structural characterization of ß-amyloid oligomer-aggregates by ion mobility mass spectrometry and electron spin resonance spectroscopy. Anal Bioanal Chem 2009; 395:2509-19. [DOI: 10.1007/s00216-009-3164-3] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2009] [Revised: 09/15/2009] [Accepted: 09/16/2009] [Indexed: 11/30/2022]
|
47
|
Effect of pseudorepeat rearrangement on alpha-synuclein misfolding, vesicle binding, and micelle binding. J Mol Biol 2009; 390:516-29. [PMID: 19481090 DOI: 10.1016/j.jmb.2009.05.058] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2009] [Revised: 05/14/2009] [Accepted: 05/18/2009] [Indexed: 01/13/2023]
Abstract
The pathological and physiological hallmarks of the protein alpha-synuclein (aS) are its misfolding into cytotoxic aggregates and its binding to synaptic vesicles, respectively. Both events are mediated by seven 11-residue amphiphilic pseudorepeats and, most generally, involve a transition from intrinsically unstructured conformations to structured conformations. Based on aS interactions with aggregation-inhibiting small molecules, an aS variant termed shuffled alpha-synuclein (SaS), wherein the first six pseudorepeats had been rearranged, was introduced. Here, the effects of this rearrangement on misfolding, vesicle binding, and micelle binding are examined in reference to aS and beta-synuclein to study the sequence characteristics underlying these processes. Fibrillization correlates with the distinct clustering of residues with high beta-sheet propensities, while vesicle affinities depend on the mode of pseudorepeat interchange and loss. In the presence of micelles, the pseudorepeat region of SaS adopts an essentially continuous helix, whereas aS and beta-synuclein encounter a distinct helix break, indicating that a more homogeneous distribution of surfactant affinities in SaS prevented the formation of an extensive helix break in the micelle-bound state. By demonstrating the importance of the distribution of beta-sheet propensities and by revealing inhomogeneous aS surfactant affinities, the present study provides novel insights into two central themes of synuclein biology.
Collapse
|
48
|
Bodner CR, Dobson CM, Bax A. Multiple tight phospholipid-binding modes of alpha-synuclein revealed by solution NMR spectroscopy. J Mol Biol 2009; 390:775-90. [PMID: 19481095 DOI: 10.1016/j.jmb.2009.05.066] [Citation(s) in RCA: 306] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2009] [Revised: 05/22/2009] [Accepted: 05/22/2009] [Indexed: 11/24/2022]
Abstract
'In dopaminergic neurons, alpha-synuclein (alphaS) partitions between a disordered cytosolic state and a lipid-bound state. Binding of alphaS to membrane phospholipids is implicated in its functional role in synaptic regulation, but also impacts fibril formation associated with Parkinson's disease. We describe here a solution NMR study in which alphaS is added to small unilamellar vesicles of a composition mimicking synaptic vesicles; the results provide evidence for multiple distinct phospholipid-binding modes of alphaS. Exchange between the free state and the lipid-bound alphaS state, and between different bound states is slow on the NMR timescale, being in the range of 1-10 s(-1). Partitioning of the binding modes is dependent on lipid/alphaS stoichiometry, and tight binding with slow-exchange kinetics is observed at stoichiometries as low as 2:1. In all lipid-bound states, a segment of residues starting at the N-terminus of alphaS adopts an alpha-helical conformation, while succeeding residues retain the characteristics of a random coil. The 40 C-terminal residues remain dynamically disordered, even at high-lipid concentrations, but can also bind to lipids to an extent that appears to be determined by the fraction of cis X-Pro peptide bonds in this region. While lipid-bound alphaS exhibits dynamic properties that preclude its direct observation by NMR, its exchange with the NMR-visible free form allows for its indirect characterization. Rapid amide-amide nuclear Overhauser enhancement buildup points to a large alpha-helical conformation, and a distinct increase in fluorescence anisotropy attributed to Tyr39 indicates an ordered environment for this "dark state." Titration of alphaS with increasing amounts of lipids suggests that the binding mode under high-lipid conditions remains qualitatively similar to that in the low-lipid case. The NMR data appear incompatible with the commonly assumed model where alphaS lies in an alpha-helical conformation on the membrane surface and instead suggest that considerable remodeling of the vesicles is induced by alphaS.
Collapse
Affiliation(s)
- Christina R Bodner
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520, USA
| | | | | |
Collapse
|