1
|
Ramalingam N, Haass C, Dettmer U. Physiological roles of α-synuclein serine-129 phosphorylation - not an oxymoron. Trends Neurosci 2024:S0166-2236(24)00085-7. [PMID: 38862330 DOI: 10.1016/j.tins.2024.05.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Revised: 04/16/2024] [Accepted: 05/06/2024] [Indexed: 06/13/2024]
Abstract
α-Synuclein (αS) is an abundant presynaptic protein that regulates neurotransmission. It is also a key protein implicated in a broad class of neurodegenerative disorders termed synucleinopathies, including Parkinson's disease (PD) and Lewy body dementia (LBD). Pathological αS deposits in these diseases, Lewy bodies (LBs)/neurites (LNs), contain about 90% of αS in its phospho-serine129 (pS129) form. Therefore, pS129 is widely used as a surrogate marker of pathology. However, recent findings demonstrate that pS129 is also physiologically triggered by neuronal activity to positively regulate synaptic transmission. In this opinion article, we contrast the literature on pathological and physiological pS129, with a special focus on the latter. We emphasize that pS129 is ambiguous and knowledge about the context is necessary to correctly interpret changes in pS129.
Collapse
Affiliation(s)
- Nagendran Ramalingam
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA.
| | - Christian Haass
- German Center for Neurodegenerative Diseases (DZNE) Munich, 81377 Munich, Germany; Chair of Metabolic Biochemistry, Biomedical Center (BMC), Faculty of Medicine, Ludwig-Maximilians-University, Munich, Germany; Munich Cluster for Systems Neurology (SyNergy), 81377 Munich, Germany
| | - Ulf Dettmer
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA.
| |
Collapse
|
2
|
Stavsky A, Parra-Rivas LA, Tal S, Riba J, Madhivanan K, Roy S, Gitler D. Synapsin E-domain is essential for α-synuclein function. eLife 2024; 12:RP89687. [PMID: 38713200 PMCID: PMC11076041 DOI: 10.7554/elife.89687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/08/2024] Open
Abstract
The cytosolic proteins synucleins and synapsins are thought to play cooperative roles in regulating synaptic vesicle (SV) recycling, but mechanistic insight is lacking. Here, we identify the synapsin E-domain as an essential functional binding-partner of α-synuclein (α-syn). Synapsin E-domain allows α-syn functionality, binds to α-syn, and is necessary and sufficient for enabling effects of α-syn at synapses of cultured mouse hippocampal neurons. Together with previous studies implicating the E-domain in clustering SVs, our experiments advocate a cooperative role for these two proteins in maintaining physiologic SV clusters.
Collapse
Affiliation(s)
- Alexandra Stavsky
- Department of Physiology and Cell Biology, Faculty of Health Sciences and School of Brain Sciences and Cognition, Ben-Gurion University of the NegevBeer ShevaIsrael
| | - Leonardo A Parra-Rivas
- Department of Pathology, University of California, San DiegoLa JollaUnited States
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research NetworkChevy ChaseUnited States
| | - Shani Tal
- Department of Physiology and Cell Biology, Faculty of Health Sciences and School of Brain Sciences and Cognition, Ben-Gurion University of the NegevBeer ShevaIsrael
| | - Jen Riba
- Department of Physiology and Cell Biology, Faculty of Health Sciences and School of Brain Sciences and Cognition, Ben-Gurion University of the NegevBeer ShevaIsrael
| | | | - Subhojit Roy
- Department of Pathology, University of California, San DiegoLa JollaUnited States
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research NetworkChevy ChaseUnited States
- Department of Neurosciences, University of California, San DiegoLa JollaUnited States
| | - Daniel Gitler
- Department of Physiology and Cell Biology, Faculty of Health Sciences and School of Brain Sciences and Cognition, Ben-Gurion University of the NegevBeer ShevaIsrael
| |
Collapse
|
3
|
Jackson J, Hoffmann C, Scifo E, Wang H, Wischhof L, Piazzesi A, Mondal M, Shields H, Zhou X, Mondin M, Ryan EB, Döring H, Prehn JHM, Rottner K, Giannone G, Nicotera P, Ehninger D, Milovanovic D, Bano D. Actin-nucleation promoting factor N-WASP influences alpha-synuclein condensates and pathology. Cell Death Dis 2024; 15:304. [PMID: 38693139 PMCID: PMC11063037 DOI: 10.1038/s41419-024-06686-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 04/07/2024] [Accepted: 04/16/2024] [Indexed: 05/03/2024]
Abstract
Abnormal intraneuronal accumulation of soluble and insoluble α-synuclein (α-Syn) is one of the main pathological hallmarks of synucleinopathies, such as Parkinson's disease (PD). It has been well documented that the reversible liquid-liquid phase separation of α-Syn can modulate synaptic vesicle condensates at the presynaptic terminals. However, α-Syn can also form liquid-like droplets that may convert into amyloid-enriched hydrogels or fibrillar polymorphs under stressful conditions. To advance our understanding on the mechanisms underlying α-Syn phase transition, we employed a series of unbiased proteomic analyses and found that actin and actin regulators are part of the α-Syn interactome. We focused on Neural Wiskott-Aldrich syndrome protein (N-WASP) because of its association with a rare early-onset familial form of PD. In cultured cells, we demonstrate that N-WASP undergoes phase separation and can be recruited to synapsin 1 liquid-like droplets, whereas it is excluded from α-Syn/synapsin 1 condensates. Consistently, we provide evidence that wsp-1/WASL loss of function alters the number and dynamics of α-Syn inclusions in the nematode Caenorhabditis elegans. Together, our findings indicate that N-WASP expression may create permissive conditions that promote α-Syn condensates and their potentially deleterious conversion into toxic species.
Collapse
Affiliation(s)
- Joshua Jackson
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Christian Hoffmann
- German Center for Neurodegenerative Diseases (DZNE), Berlin, Germany
- Einstein Center for Neuroscience, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Enzo Scifo
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Han Wang
- German Center for Neurodegenerative Diseases (DZNE), Berlin, Germany
| | - Lena Wischhof
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Antonia Piazzesi
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | | | - Hanna Shields
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Xuesi Zhou
- University Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, Bordeaux, France
| | - Magali Mondin
- University Bordeaux, CNRS, INSERM, BIC, UAR 3420, F-33000, Bordeaux, France
| | - Eanna B Ryan
- RCSI Centre for Systems Medicine and Department of Physiology and Medical Physics, RCSI University of Medicine and Health Sciences; SFI FutureNeuro Research Centre, Dublin 2, Ireland
| | - Hermann Döring
- Division of Molecular Cell Biology, Zoological Institute, Technische Universität Braunschweig; Department of Cell Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Jochen H M Prehn
- RCSI Centre for Systems Medicine and Department of Physiology and Medical Physics, RCSI University of Medicine and Health Sciences; SFI FutureNeuro Research Centre, Dublin 2, Ireland
| | - Klemens Rottner
- Division of Molecular Cell Biology, Zoological Institute, Technische Universität Braunschweig; Department of Cell Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Gregory Giannone
- University Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, Bordeaux, France
| | | | - Dan Ehninger
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany.
| | - Dragomir Milovanovic
- German Center for Neurodegenerative Diseases (DZNE), Berlin, Germany.
- Einstein Center for Neuroscience, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität Berlin, and Berlin Institute of Health, Berlin, Germany.
| | - Daniele Bano
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany.
| |
Collapse
|
4
|
Ray S, Buell AK. Emerging experimental methods to study the thermodynamics of biomolecular condensate formation. J Chem Phys 2024; 160:091001. [PMID: 38445729 DOI: 10.1063/5.0190160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Accepted: 02/15/2024] [Indexed: 03/07/2024] Open
Abstract
The formation of biomolecular condensates in vivo is increasingly recognized to underlie a multitude of crucial cellular functions. Furthermore, the evolution of highly dynamic protein condensates into progressively less reversible assemblies is thought to be involved in a variety of disorders, from cancer over neurodegeneration to rare genetic disorders. There is an increasing need for efficient experimental methods to characterize the thermodynamics of condensate formation and that can be used in screening campaigns to identify and rationally design condensate modifying compounds. Theoretical advances in the field are also identifying the key parameters that need to be measured in order to obtain a comprehensive understanding of the underlying interactions and driving forces. Here, we review recent progress in the development of efficient and quantitative experimental methods to study the driving forces behind and the temporal evolution of biomolecular condensates.
Collapse
Affiliation(s)
- Soumik Ray
- Department of Biotechnology and Biomedicine, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Alexander K Buell
- Department of Biotechnology and Biomedicine, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| |
Collapse
|
5
|
Alfken J, Neuhaus C, Major A, Taskina A, Hoffmann C, Ganzella M, Petrovic A, Zwicker D, Fernández-Busnadiego R, Jahn R, Milovanovic D, Salditt T. Vesicle condensation induced by synapsin: condensate size, geometry, and vesicle shape deformations. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2024; 47:8. [PMID: 38270681 DOI: 10.1140/epje/s10189-023-00404-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 12/28/2023] [Indexed: 01/26/2024]
Abstract
We study the formation of vesicle condensates induced by the protein synapsin, as a cell-free model system mimicking vesicle pool formation in the synapse. The system can be considered as an example of liquid-liquid phase separation (LLPS) in biomolecular fluids, where one phase is a complex fluid itself consisting of vesicles and a protein network. We address the pertinent question why the LLPS is self-limiting and stops at a certain size, i.e., why macroscopic phase separation is prevented. Using fluorescence light microscopy, we observe different morphologies of the condensates (aggregates) depending on the protein-to-lipid ratio. Cryogenic electron microscopy then allows us to resolve individual vesicle positions and shapes in a condensate and notably the size and geometry of adhesion zones between vesicles. We hypothesize that the membrane tension induced by already formed adhesion zones then in turn limits the capability of vesicles to bind additional vesicles, resulting in a finite condensate size. In a simple numerical toy model we show that this effect can be accounted for by redistribution of effective binding particles on the vesicle surface, accounting for the synapsin-induced adhesion zone.
Collapse
Affiliation(s)
- Jette Alfken
- Institut für Röntgenphysik, Georg-August-Universität, Friedrich-Hund-Platz 1, 37077, Göttingen, Germany
| | - Charlotte Neuhaus
- Institut für Röntgenphysik, Georg-August-Universität, Friedrich-Hund-Platz 1, 37077, Göttingen, Germany
| | - András Major
- Institut für Röntgenphysik, Georg-August-Universität, Friedrich-Hund-Platz 1, 37077, Göttingen, Germany
| | - Alyona Taskina
- Institut für Röntgenphysik, Georg-August-Universität, Friedrich-Hund-Platz 1, 37077, Göttingen, Germany
- Theorie Biologischer Flüssigkeiten, Max-Planck-Institut für Dynamik und Selbstorganisation, Am Fassberg 11, 37077, Göttingen, Germany
| | - Christian Hoffmann
- Molekulare Neurowissenschaften, Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Charitéplatz 1, 10117, Berlin, Germany
| | - Marcelo Ganzella
- Labor für Neurobiologie, Max-Planck-Institut für multidisziplinäre Naturwissenschaften, Am Fassberg 11, 37077, Göttingen, Germany
| | - Arsen Petrovic
- Institut für Neuropathologie, Universitätsmedizin Göttingen, Justus-von-Liebig-Weg 11, 37077, Göttingen, Germany
| | - David Zwicker
- Theorie Biologischer Flüssigkeiten, Max-Planck-Institut für Dynamik und Selbstorganisation, Am Fassberg 11, 37077, Göttingen, Germany
| | - Rubén Fernández-Busnadiego
- Institut für Neuropathologie, Universitätsmedizin Göttingen, Justus-von-Liebig-Weg 11, 37077, Göttingen, Germany
| | - Reinhard Jahn
- Labor für Neurobiologie, Max-Planck-Institut für multidisziplinäre Naturwissenschaften, Am Fassberg 11, 37077, Göttingen, Germany
| | - Dragomir Milovanovic
- Molekulare Neurowissenschaften, Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Charitéplatz 1, 10117, Berlin, Germany
| | - Tim Salditt
- Institut für Röntgenphysik, Georg-August-Universität, Friedrich-Hund-Platz 1, 37077, Göttingen, Germany.
| |
Collapse
|
6
|
de Raffele D, Ilie IM. Unlocking novel therapies: cyclic peptide design for amyloidogenic targets through synergies of experiments, simulations, and machine learning. Chem Commun (Camb) 2024; 60:632-645. [PMID: 38131333 DOI: 10.1039/d3cc04630c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2023]
Abstract
Existing therapies for neurodegenerative diseases like Parkinson's and Alzheimer's address only their symptoms and do not prevent disease onset. Common therapeutic agents, such as small molecules and antibodies struggle with insufficient selectivity, stability and bioavailability, leading to poor performance in clinical trials. Peptide-based therapeutics are emerging as promising candidates, with successful applications for cardiovascular diseases and cancers due to their high bioavailability, good efficacy and specificity. In particular, cyclic peptides have a long in vivo stability, while maintaining a robust antibody-like binding affinity. However, the de novo design of cyclic peptides is challenging due to the lack of long-lived druggable pockets of the target polypeptide, absence of exhaustive conformational distributions of the target and/or the binder, unknown binding site, methodological limitations, associated constraints (failed trials, time, money) and the vast combinatorial sequence space. Hence, efficient alignment and cooperation between disciplines, and synergies between experiments and simulations complemented by popular techniques like machine-learning can significantly speed up the therapeutic cyclic-peptide development for neurodegenerative diseases. We review the latest advancements in cyclic peptide design against amyloidogenic targets from a computational perspective in light of recent advancements and potential of machine learning to optimize the design process. We discuss the difficulties encountered when designing novel peptide-based inhibitors and we propose new strategies incorporating experiments, simulations and machine learning to design cyclic peptides to inhibit the toxic propagation of amyloidogenic polypeptides. Importantly, these strategies extend beyond the mere design of cyclic peptides and serve as template for the de novo generation of (bio)materials with programmable properties.
Collapse
Affiliation(s)
- Daria de Raffele
- University of Amsterdam, van 't Hoff Institute for Molecular Sciences, Science Park 904, P.O. Box 94157, 1090 GD Amsterdam, The Netherlands.
- Amsterdam Center for Multiscale Modeling (ACMM), University of Amsterdam, P.O. Box 94157, 1090 GD Amsterdam, The Netherlands
| | - Ioana M Ilie
- University of Amsterdam, van 't Hoff Institute for Molecular Sciences, Science Park 904, P.O. Box 94157, 1090 GD Amsterdam, The Netherlands.
- Amsterdam Center for Multiscale Modeling (ACMM), University of Amsterdam, P.O. Box 94157, 1090 GD Amsterdam, The Netherlands
| |
Collapse
|
7
|
Moors TE, Milovanovic D. Defining a Lewy Body: Running Up the Hill of Shifting Definitions and Evolving Concepts. JOURNAL OF PARKINSON'S DISEASE 2024; 14:17-33. [PMID: 38189713 PMCID: PMC10836569 DOI: 10.3233/jpd-230183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 11/14/2023] [Indexed: 01/09/2024]
Abstract
Lewy bodies (LBs) are pathological hallmarks of Parkinson's disease and dementia with Lewy bodies, characterized by the accumulation of α-synuclein (αSyn) protein in the brain. While LBs were first described a century ago, their formation and morphogenesis mechanisms remain incompletely understood. Here, we present a historical overview of LB definitions and highlight the importance of semantic clarity and precise definitions when describing brain inclusions. Recent breakthroughs in imaging revealed shared features within LB subsets and the enrichment of membrane-bound organelles in these structures, challenging the conventional LB formation model. We discuss the involvement of emerging concepts of liquid-liquid phase separation, where biomolecules demix from a solution to form dense condensates, as a potential LB formation mechanism. Finally, we emphasize the need for the operational definitions of LBs based on morphological characteristics and detection protocols, particularly in studies investigating LB formation mechanisms. A better understanding of LB organization and ultrastructure can contribute to the development of targeted therapeutic strategies for synucleinopathies.
Collapse
Affiliation(s)
- Tim E. Moors
- Ann Romney Center for Neurologic Diseases, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA, USA
| | - Dragomir Milovanovic
- Laboratory of Molecular Neuroscience, German Center for Neurodegenerative Diseases (DZNE), Berlin, Germany
- Einstein Center for Neuroscience, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität Berlin, and Berlin Institute of Health, Berlin, Germany
| |
Collapse
|
8
|
Wallace JN, Crockford ZC, Román-Vendrell C, Brady EB, Hoffmann C, Vargas KJ, Potcoava M, Wegman ME, Alford ST, Milovanovic D, Morgan JR. Excess phosphoserine-129 α-synuclein induces synaptic vesicle trafficking and declustering defects at a vertebrate synapse. Mol Biol Cell 2024; 35:ar10. [PMID: 37991902 PMCID: PMC10881165 DOI: 10.1091/mbc.e23-07-0269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 11/06/2023] [Accepted: 11/06/2023] [Indexed: 11/24/2023] Open
Abstract
α-Synuclein is a presynaptic protein that regulates synaptic vesicle (SV) trafficking. In Parkinson's disease (PD) and dementia with Lewy bodies (DLB), α-synuclein aberrantly accumulates throughout neurons, including at synapses. During neuronal activity, α-synuclein is reversibly phosphorylated at serine 129 (pS129). While pS129 comprises ∼4% of total α-synuclein under physiological conditions, it dramatically increases in PD and DLB brains. The impacts of excess pS129 on synaptic function are currently unknown. We show here that compared with wild-type (WT) α-synuclein, pS129 exhibits increased binding and oligomerization on synaptic membranes and enhanced vesicle "microclustering" in vitro. Moreover, when acutely injected into lamprey reticulospinal axons, excess pS129 α-synuclein robustly localized to synapses and disrupted SV trafficking in an activity-dependent manner, as assessed by ultrastructural analysis. Specifically, pS129 caused a declustering and dispersion of SVs away from the synaptic vicinity, leading to a significant loss of total synaptic membrane. Live imaging further revealed altered SV cycling, as well as microclusters of recently endocytosed SVs moving away from synapses. Thus, excess pS129 caused an activity-dependent inhibition of SV trafficking via altered vesicle clustering/reclustering. This work suggests that accumulation of pS129 at synapses in diseases like PD and DLB could have profound effects on SV dynamics.
Collapse
Affiliation(s)
| | | | | | - Emily B. Brady
- Eugene Bell Center for Regenerative Biology and Tissue Engineering, and
| | - Christian Hoffmann
- Whitman Center, Marine Biological Laboratory, Woods Hole, MA 02543
- Laboratory of Molecular Neuroscience, German Center for Neurodegenerative Diseases (DZNE), 10117 Berlin, Germany
| | - Karina J. Vargas
- Eugene Bell Center for Regenerative Biology and Tissue Engineering, and
- Department of Cell Biology, University of Pittsburgh, PA 15261
| | - Mariana Potcoava
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL 60612
| | | | - Simon T. Alford
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL 60612
| | - Dragomir Milovanovic
- Whitman Center, Marine Biological Laboratory, Woods Hole, MA 02543
- Laboratory of Molecular Neuroscience, German Center for Neurodegenerative Diseases (DZNE), 10117 Berlin, Germany
| | | |
Collapse
|
9
|
Hoffmann C, Milovanovic D. Dipping contacts - a novel type of contact site at the interface between membraneless organelles and membranes. J Cell Sci 2023; 136:jcs261413. [PMID: 38149872 PMCID: PMC10785658 DOI: 10.1242/jcs.261413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2023] Open
Abstract
Liquid-liquid phase separation is a major mechanism for organizing macromolecules, particularly proteins with intrinsically disordered regions, in compartments not limited by a membrane or a scaffold. The cell can therefore be perceived as a complex emulsion containing many of these membraneless organelles, also referred to as biomolecular condensates, together with numerous membrane-bound organelles. It is currently unclear how such a complex concoction operates to allow for intracellular trafficking, signaling and metabolic processes to occur with high spatiotemporal precision. Based on experimental observations of synaptic vesicle condensates - a membraneless organelle that is in fact packed with membranes - we present here the framework of dipping contacts: a novel type of contact site between membraneless organelles and membranes. In this Hypothesis, we propose that our framework of dipping contacts can serve as a foundation to investigate the interface that couples the diffusion and material properties of condensates to biochemical processes occurring in membranes. The identity and regulation of this interface is especially critical in the case of neurodegenerative diseases, where aberrant inclusions of misfolded proteins and damaged organelles underlie cellular pathology.
Collapse
Affiliation(s)
- Christian Hoffmann
- Laboratory of Molecular Neuroscience, German Center for Neurodegenerative Diseases (DZNE), 10117 Berlin, Germany
- Whitman Center, Marine Biological Laboratory, Woods Hole, MA 02543, USA
| | - Dragomir Milovanovic
- Laboratory of Molecular Neuroscience, German Center for Neurodegenerative Diseases (DZNE), 10117 Berlin, Germany
- Whitman Center, Marine Biological Laboratory, Woods Hole, MA 02543, USA
- National Center for X-ray Tomography, Advanced Light Source, Berkeley, CA 94720, USA
- Einstein Center for Neuroscience, Charité-Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität Berlin and Berlin Institute of Health, 10117 Berlin, Germany
| |
Collapse
|
10
|
Hoffmann C, Murastov G, Tromm JV, Moog JB, Aslam MA, Matkovic A, Milovanovic D. Electric Potential at the Interface of Membraneless Organelles Gauged by Graphene. NANO LETTERS 2023; 23:10796-10801. [PMID: 37862690 PMCID: PMC10722609 DOI: 10.1021/acs.nanolett.3c02915] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 10/15/2023] [Indexed: 10/22/2023]
Abstract
Eukaryotic cells contain membrane-bound and membrane-less organelles that are often in contact with each other. How the interface properties of membrane-less organelles regulate their interactions with membranes remains challenging to assess. Here, we employ graphene-based sensors to investigate the electrostatic properties of synapsin 1, a major synaptic phosphoprotein, either in a single phase or after undergoing phase separation to form synapsin condensates. Using these graphene-based sensors, we discover that synapsin condensates generate strong electrical responses that are otherwise absent when synapsin is present as a single phase. By introducing atomically thin dielectric barriers, we show that the electrical response originates in an electric double layer whose formation governs the interaction between synapsin condensates and graphene. Our data indicate that the interface properties of the same protein are substantially different when the protein is in a single phase versus within a biomolecular condensate, unraveling that condensates can harbor ion potential differences at their interface.
Collapse
Affiliation(s)
- Christian Hoffmann
- Laboratory
of Molecular Neuroscience, German Center
for Neurodegenerative Diseases (DZNE), 10117 Berlin, Germany
| | - Gennadiy Murastov
- Chair
of Physics, Department Physics, Mechanics and Electrical Engineering, Montanuniversität Leoben, 8700 Leoben, Austria
| | - Johannes Vincent Tromm
- Laboratory
of Molecular Neuroscience, German Center
for Neurodegenerative Diseases (DZNE), 10117 Berlin, Germany
| | - Jean-Baptiste Moog
- Laboratory
of Molecular Neuroscience, German Center
for Neurodegenerative Diseases (DZNE), 10117 Berlin, Germany
| | - Muhammad Awais Aslam
- Chair
of Physics, Department Physics, Mechanics and Electrical Engineering, Montanuniversität Leoben, 8700 Leoben, Austria
| | - Aleksandar Matkovic
- Chair
of Physics, Department Physics, Mechanics and Electrical Engineering, Montanuniversität Leoben, 8700 Leoben, Austria
| | - Dragomir Milovanovic
- Laboratory
of Molecular Neuroscience, German Center
for Neurodegenerative Diseases (DZNE), 10117 Berlin, Germany
| |
Collapse
|
11
|
Czajka T, Neuhaus C, Alfken J, Stammer M, Chushkin Y, Pontoni D, Hoffmann C, Milovanovic D, Salditt T. Lipid vesicle pools studied by passive X-ray microrheology. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2023; 46:123. [PMID: 38060069 PMCID: PMC10703982 DOI: 10.1140/epje/s10189-023-00375-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Accepted: 11/07/2023] [Indexed: 12/08/2023]
Abstract
Vesicle pools can form by attractive interaction in a solution, mediated by proteins or divalent ions such as calcium. The pools, which are alternatively also denoted as vesicle clusters, form by liquid-liquid phase separation (LLPS) from an initially homogeneous solution. Due to the short range liquid-like order of vesicles in the pool or cluster, the vesicle-rich phase can also be regarded as a condensate, and one would like to better understand not only the structure of these systems, but also their dynamics. The diffusion of vesicles, in particular, is expected to change when vesicles are arrested in a pool. Here we investigate whether passive microrheology based on X-ray photon correlation spectroscopy (XPCS) is a suitable tool to study model systems of artificial lipid vesicles exhibiting LLPS, and more generally also other heterogeneous biomolecular fluids. We show that by adding highly scattering tracer particles to the solution, valuable information on the single vesicle as well as collective dynamics can be inferred. While the correlation functions reveal freely diffusing tracer particles in solutions at low CaCl[Formula: see text] concentrations, the relaxation rate [Formula: see text] shows a nonlinear dependence on [Formula: see text] at a higher concentration of around 8 mM CaCl[Formula: see text], characterised by two linear regimes with a broad cross-over. We explain this finding based on arrested diffusion in percolating vesicle clusters.
Collapse
Affiliation(s)
- Titus Czajka
- Institut für Röntgenphysik, Georg-August-Universität Göttingen, 37077, Göttingen, Germany
| | - Charlotte Neuhaus
- Institut für Röntgenphysik, Georg-August-Universität Göttingen, 37077, Göttingen, Germany
| | - Jette Alfken
- Institut für Röntgenphysik, Georg-August-Universität Göttingen, 37077, Göttingen, Germany
| | - Moritz Stammer
- Institut für Röntgenphysik, Georg-August-Universität Göttingen, 37077, Göttingen, Germany
| | - Yuriy Chushkin
- European Synchrotron Radiation Facility, 38043, Grenoble Cedex 9, France
| | - Diego Pontoni
- European Synchrotron Radiation Facility, 38043, Grenoble Cedex 9, France
| | - Christian Hoffmann
- Laboratory of Molecular Neuroscience, German Center for Neurodegenerative Diseases (DZNE), 10117, Berlin, Germany
| | - Dragomir Milovanovic
- Laboratory of Molecular Neuroscience, German Center for Neurodegenerative Diseases (DZNE), 10117, Berlin, Germany
| | - Tim Salditt
- Institut für Röntgenphysik, Georg-August-Universität Göttingen, 37077, Göttingen, Germany.
| |
Collapse
|
12
|
Li Q, Song Q, Guo W, Cao Y, Cui X, Chen D, Shum HC. Synthetic Membraneless Droplets for Synaptic-Like Clustering of Lipid Vesicles. Angew Chem Int Ed Engl 2023; 62:e202313096. [PMID: 37728515 DOI: 10.1002/anie.202313096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 09/19/2023] [Accepted: 09/20/2023] [Indexed: 09/21/2023]
Abstract
In eukaryotic cells, the membraneless organelles (MLOs) formed via liquid-liquid phase separation (LLPS) are found to interact intimately with membranous organelles (MOs). One major mode is the clustering of MOs by MLOs, such as the formation of clusters of synaptic vesicles at nerve terminals mediated by the synapsin-rich MLOs. Aqueous droplets, including complex coacervates and aqueous two-phase systems, have been plausible MLO-mimics to emulate or elucidate biological processes. However, neither of them can cluster lipid vesicles (LVs) like MLOs. In this work, we develop a synthetic droplet assembled from a combination of two different interactions underlying the formation of these two droplets, namely, associative and segregative interactions, which we call segregative-associative (SA) droplets. The SA droplets cluster and disperse LVs recapitulating the key functional features of synapsin condensates, which can be attributed to the weak electrostatic interaction environment provided by SA droplets. This work suggests LLPS with combined segregative and associative interactions as a possible route for synaptic clustering of lipid vesicles and highlights SA droplets as plausible MLO-mimics and models for studying and mimicking related cellular dynamics.
Collapse
Affiliation(s)
- Qingchuan Li
- School of Chemistry & Chemical Engineering, National Engineering Research Center for Colloidal Materials, Shandong University, 27 Shanda Nanlu, Jinan, Shandong, P.R.China
- Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong, China
- Advanced Biomedical Instrumentation Centre, Hong Kong Science Park, Shatin, New Territories, Hong Kong (SAR), Hong Kong, China
| | - Qingchun Song
- Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Wei Guo
- Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong, China
- Advanced Biomedical Instrumentation Centre, Hong Kong Science Park, Shatin, New Territories, Hong Kong (SAR), Hong Kong, China
| | - Yang Cao
- Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Xinyu Cui
- Department of Public Health, Mudanjiang Medical University, Mudanjiang, 157000, P. R. China
| | - Dairong Chen
- School of Chemistry & Chemical Engineering, National Engineering Research Center for Colloidal Materials, Shandong University, 27 Shanda Nanlu, Jinan, Shandong, P.R.China
| | - Ho Cheung Shum
- Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong, China
- Advanced Biomedical Instrumentation Centre, Hong Kong Science Park, Shatin, New Territories, Hong Kong (SAR), Hong Kong, China
| |
Collapse
|
13
|
Sigrist SJ, Haucke V. Orchestrating vesicular and nonvesicular membrane dynamics by intrinsically disordered proteins. EMBO Rep 2023; 24:e57758. [PMID: 37680133 PMCID: PMC10626433 DOI: 10.15252/embr.202357758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 08/22/2023] [Accepted: 08/24/2023] [Indexed: 09/09/2023] Open
Abstract
Compartmentalization by membranes is a common feature of eukaryotic cells and serves to spatiotemporally confine biochemical reactions to control physiology. Membrane-bound organelles such as the endoplasmic reticulum (ER), the Golgi complex, endosomes and lysosomes, and the plasma membrane, continuously exchange material via vesicular carriers. In addition to vesicular trafficking entailing budding, fission, and fusion processes, organelles can form membrane contact sites (MCSs) that enable the nonvesicular exchange of lipids, ions, and metabolites, or the secretion of neurotransmitters via subsequent membrane fusion. Recent data suggest that biomolecule and information transfer via vesicular carriers and via MCSs share common organizational principles and are often mediated by proteins with intrinsically disordered regions (IDRs). Intrinsically disordered proteins (IDPs) can assemble via low-affinity, multivalent interactions to facilitate membrane tethering, deformation, fission, or fusion. Here, we review our current understanding of how IDPs drive the formation of multivalent protein assemblies and protein condensates to orchestrate vesicular and nonvesicular transport with a special focus on presynaptic neurotransmission. We further discuss how dysfunction of IDPs causes disease and outline perspectives for future research.
Collapse
Affiliation(s)
- Stephan J Sigrist
- Department of Biology, Chemistry, PharmacyFreie Universität BerlinBerlinGermany
| | - Volker Haucke
- Department of Biology, Chemistry, PharmacyFreie Universität BerlinBerlinGermany
- Department of Molecular Pharmacology and Cell BiologyLeibniz Forschungsinstitut für Molekulare Pharmakologie (FMP)BerlinGermany
| |
Collapse
|
14
|
Hoffmann C, Rentsch J, Tsunoyama TA, Chhabra A, Aguilar Perez G, Chowdhury R, Trnka F, Korobeinikov AA, Shaib AH, Ganzella M, Giannone G, Rizzoli SO, Kusumi A, Ewers H, Milovanovic D. Synapsin condensation controls synaptic vesicle sequestering and dynamics. Nat Commun 2023; 14:6730. [PMID: 37872159 PMCID: PMC10593750 DOI: 10.1038/s41467-023-42372-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 10/09/2023] [Indexed: 10/25/2023] Open
Abstract
Neuronal transmission relies on the regulated secretion of neurotransmitters, which are packed in synaptic vesicles (SVs). Hundreds of SVs accumulate at synaptic boutons. Despite being held together, SVs are highly mobile, so that they can be recruited to the plasma membrane for their rapid release during neuronal activity. However, how such confinement of SVs corroborates with their motility remains unclear. To bridge this gap, we employ ultrafast single-molecule tracking (SMT) in the reconstituted system of native SVs and in living neurons. SVs and synapsin 1, the most highly abundant synaptic protein, form condensates with liquid-like properties. In these condensates, synapsin 1 movement is slowed in both at short (i.e., 60-nm) and long (i.e., several hundred-nm) ranges, suggesting that the SV-synapsin 1 interaction raises the overall packing of the condensate. Furthermore, two-color SMT and super-resolution imaging in living axons demonstrate that synapsin 1 drives the accumulation of SVs in boutons. Even the short intrinsically-disordered fragment of synapsin 1 was sufficient to restore the native SV motility pattern in synapsin triple knock-out animals. Thus, synapsin 1 condensation is sufficient to guarantee reliable confinement and motility of SVs, allowing for the formation of mesoscale domains of SVs at synapses in vivo.
Collapse
Affiliation(s)
- Christian Hoffmann
- Laboratory of Molecular Neuroscience, German Center for Neurodegenerative Diseases (DZNE), 10117, Berlin, Germany
| | - Jakob Rentsch
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, 14195, Berlin, Germany
| | - Taka A Tsunoyama
- Membrane Cooperativity Unit, Okinawa Institute of Science and Technology Graduate University (OIST); Onna-son, Okinawa, 904-0495, Japan
| | - Akshita Chhabra
- Laboratory of Molecular Neuroscience, German Center for Neurodegenerative Diseases (DZNE), 10117, Berlin, Germany
| | - Gerard Aguilar Perez
- Laboratory of Molecular Neuroscience, German Center for Neurodegenerative Diseases (DZNE), 10117, Berlin, Germany
| | - Rajdeep Chowdhury
- University Medical Center Göttingen, Institute for Neuro- and Sensory Physiology, Germany; Biostructural Imaging of Neurodegeneration (BIN) Center, Göttingen, Germany; Excellence Cluster Multiscale Bioimaging, 37073, Göttingen, Germany
| | - Franziska Trnka
- Laboratory of Molecular Neuroscience, German Center for Neurodegenerative Diseases (DZNE), 10117, Berlin, Germany
| | - Aleksandr A Korobeinikov
- Laboratory of Molecular Neuroscience, German Center for Neurodegenerative Diseases (DZNE), 10117, Berlin, Germany
| | - Ali H Shaib
- University Medical Center Göttingen, Institute for Neuro- and Sensory Physiology, Germany; Biostructural Imaging of Neurodegeneration (BIN) Center, Göttingen, Germany; Excellence Cluster Multiscale Bioimaging, 37073, Göttingen, Germany
| | - Marcelo Ganzella
- Department of Neurobiology, Max Planck Institute for Multidisciplinary Sciences, 37077, Göttingen, Germany
| | - Gregory Giannone
- Interdisciplinary Institute for Neuroscience, University of Bordeaux, UMR 5297, F-33000, Bordeaux, France
| | - Silvio O Rizzoli
- University Medical Center Göttingen, Institute for Neuro- and Sensory Physiology, Germany; Biostructural Imaging of Neurodegeneration (BIN) Center, Göttingen, Germany; Excellence Cluster Multiscale Bioimaging, 37073, Göttingen, Germany
| | - Akihiro Kusumi
- Membrane Cooperativity Unit, Okinawa Institute of Science and Technology Graduate University (OIST); Onna-son, Okinawa, 904-0495, Japan
| | - Helge Ewers
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, 14195, Berlin, Germany
| | - Dragomir Milovanovic
- Laboratory of Molecular Neuroscience, German Center for Neurodegenerative Diseases (DZNE), 10117, Berlin, Germany.
| |
Collapse
|
15
|
Hou K, Liu T, Li J, Xian M, Sun L, Wei J. Liquid-liquid phase separation regulates alpha-synuclein aggregate and mitophagy in Parkinson's disease. Front Neurosci 2023; 17:1250532. [PMID: 37781241 PMCID: PMC10536155 DOI: 10.3389/fnins.2023.1250532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 08/29/2023] [Indexed: 10/03/2023] Open
Abstract
Parkinson's disease (PD) is the second most common neurodegenerative disease in the world, and alpha-synuclein (α-syn) abnormal aggregate and mitochondrial dysfunction play a crucial role in its pathological development. Recent studies have revealed that proteins can form condensates through liquid-liquid phase separation (LLPS), and LLPS has been found to be widely present in α-syn aberrant aggregate and mitophagy-related protein physiological processes. This review summarizes the occurrence of α-syn LLPS and its influencing factors, introduces the production and transformation of the related protein LLPS during PINK1-Parkin-mediated mitophagy, hoping to provide new ideas and methods for the study of PD pathology.
Collapse
Affiliation(s)
- Kaiying Hou
- School of Life Sciences, Henan University, Kaifeng, China
| | - Tingting Liu
- School of Life Sciences, Henan University, Kaifeng, China
| | - Jingwen Li
- School of Life Sciences, Henan University, Kaifeng, China
| | - Meiyan Xian
- School of Life Sciences, Henan University, Kaifeng, China
| | - Lin Sun
- College of Chemistry and Molecular Sciences, Henan University, Kaifeng, China
| | - Jianshe Wei
- School of Life Sciences, Henan University, Kaifeng, China
| |
Collapse
|
16
|
Song SH, Augustine GJ. Different mechanisms of synapsin-induced vesicle clustering at inhibitory and excitatory synapses. Cell Rep 2023; 42:113004. [PMID: 37597184 DOI: 10.1016/j.celrep.2023.113004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 06/26/2023] [Accepted: 08/02/2023] [Indexed: 08/21/2023] Open
Abstract
Synapsins cluster synaptic vesicles (SVs) to provide a reserve pool (RP) of SVs that maintains synaptic transmission during sustained activity. However, it is unclear how synapsins cluster SVs. Here we show that either liquid-liquid phase separation (LLPS) or tetramerization-dependent cross-linking can cluster SVs, depending on whether a synapse is excitatory or inhibitory. Cell-free reconstitution reveals that both mechanisms can cluster SVs, with tetramerization being more effective. At inhibitory synapses, perturbing synapsin-dependent LLPS impairs SV clustering and synchronization of gamma-aminobutyric acid (GABA) release, while preventing synapsin tetramerization does not. At glutamatergic synapses, the opposite is true: synapsin tetramerization enhances clustering of glutamatergic SVs and mobilization of these SVs from the RP, while synapsin LLPS does not. Comparison of inhibitory and excitatory transmission during prolonged synaptic activity reveals that synapsin LLPS serves as a brake to limit GABA release, while synapsin tetramerization enables rapid mobilization of SVs from the RP to sustain glutamate release.
Collapse
Affiliation(s)
- Sang-Ho Song
- Neuroscience and Mental Health Program, Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 308232, Singapore
| | - George J Augustine
- Neuroscience and Mental Health Program, Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 308232, Singapore.
| |
Collapse
|
17
|
Ogunmowo T, Hoffmann C, Pepper R, Wang H, Gowrisankaran S, Ho A, Raychaudhuri S, Cooper BH, Milosevic I, Milovanovic D, Watanabe S. Intersectin and Endophilin condensates prime synaptic vesicles for release site replenishment. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.22.554276. [PMID: 37662300 PMCID: PMC10473601 DOI: 10.1101/2023.08.22.554276] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
Neurotransmitter is released from dedicated sites of synaptic vesicle fusion within a synapse. Following fusion, the vacated sites are replenished immediately by new vesicles for subsequent neurotransmission. These replacement vesicles are assumed to be located near release sites and used by chance. Here, we find that replacement vesicles are clustered around this region by Intersectin-1. Specifically, Intersectin-1 forms dynamic molecular condensates with Endophilin A1 near release sites and sequesters vesicles around this region. In the absence of Intersectin-1, vesicles within 20 nm of the plasma membrane are reduced, and consequently, vacated sites cannot be replenished rapidly, leading to depression of synaptic transmission. Similarly, mutations in Intersectin-1 that disrupt Endophilin A1 binding result in similar phenotypes. However, in the absence of Endophilin, this replacement pool of vesicles is available but cannot be accessed, suggesting that Endophilin A1 is needed to mobilize these vesicles. Thus, our work describes a distinct physical region within a synapse where replacement vesicles are harbored for release site replenishment.
Collapse
Affiliation(s)
- Tyler Ogunmowo
- Department of Cell Biology, Johns Hopkins University, School of Medicine, Baltimore, MD USA
| | - Christian Hoffmann
- Laboratory of Molecular Neuroscience, German Center for Neurodegenerative Diseases (DZNE), Berlin, Germany
| | - Renee Pepper
- Department of Cell Biology, Johns Hopkins University, School of Medicine, Baltimore, MD USA
| | - Han Wang
- Laboratory of Molecular Neuroscience, German Center for Neurodegenerative Diseases (DZNE), Berlin, Germany
| | | | - Annie Ho
- Department of Cell Biology, Johns Hopkins University, School of Medicine, Baltimore, MD USA
| | - Sumana Raychaudhuri
- Department of Cell Biology, Johns Hopkins University, School of Medicine, Baltimore, MD USA
| | - Benjamin H. Cooper
- Department of Molecular Neurobiology, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Ira Milosevic
- Multidisciplinary Institute of Ageing, University of Coimbra, Coimbra, Portugal
- Nuffield Department of Medicine, Wellcome Centre for Human Genetics, NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford, UK
| | - Dragomir Milovanovic
- Laboratory of Molecular Neuroscience, German Center for Neurodegenerative Diseases (DZNE), Berlin, Germany
- Einstein Center for Neuroscience, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität Berlin, and Berlin Institute of Health, 10117 Berlin, Germany
| | - Shigeki Watanabe
- Department of Cell Biology, Johns Hopkins University, School of Medicine, Baltimore, MD USA
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, School of Medicine, Baltimore, MD USA
| |
Collapse
|
18
|
Piroska L, Fenyi A, Thomas S, Plamont MA, Redeker V, Melki R, Gueroui Z. α-Synuclein liquid condensates fuel fibrillar α-synuclein growth. SCIENCE ADVANCES 2023; 9:eadg5663. [PMID: 37585526 PMCID: PMC10431715 DOI: 10.1126/sciadv.adg5663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Accepted: 07/13/2023] [Indexed: 08/18/2023]
Abstract
α-Synuclein (α-Syn) aggregation into fibrils with prion-like features is intimately associated with Lewy pathology and various synucleinopathies. Emerging studies suggest that α-Syn could form liquid condensates through phase separation. The role of these condensates in aggregation and disease remains elusive and the interplay between α-Syn fibrils and α-Syn condensates remains unexplored, possibly due to difficulties in triggering the formation of α-Syn condensates in cells. To address this gap, we developed an assay allowing the controlled assembly/disassembly of α-Syn condensates in cells and studied them upon exposure to preformed α-Syn fibrillar polymorphs. Fibrils triggered the evolution of liquid α-Syn condensates into solid-like structures displaying growing needle-like extensions and exhibiting pathological amyloid hallmarks. No such changes were elicited on α-Syn that did not undergo phase separation. We, therefore, propose a model where α-Syn within condensates fuels exogenous fibrillar seeds growth, thus speeding up the prion-like propagation of pathogenic aggregates.
Collapse
Affiliation(s)
- Leonard Piroska
- PASTEUR, Department of Chemistry, École Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France
| | - Alexis Fenyi
- Institut Francois Jacob (MIRCen), CEA, CNRS, Fontenay-aux-Roses, France
| | - Scott Thomas
- PASTEUR, Department of Chemistry, École Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France
| | - Marie-Aude Plamont
- PASTEUR, Department of Chemistry, École Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France
| | - Virginie Redeker
- Institut Francois Jacob (MIRCen), CEA, CNRS, Fontenay-aux-Roses, France
| | - Ronald Melki
- Institut Francois Jacob (MIRCen), CEA, CNRS, Fontenay-aux-Roses, France
| | - Zoher Gueroui
- PASTEUR, Department of Chemistry, École Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France
| |
Collapse
|
19
|
Cordeiro Y, Freire MHO, Wiecikowski AF, do Amaral MJ. (Dys)functional insights into nucleic acids and RNA-binding proteins modulation of the prion protein and α-synuclein phase separation. Biophys Rev 2023; 15:577-589. [PMID: 37681103 PMCID: PMC10480379 DOI: 10.1007/s12551-023-01067-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Accepted: 05/22/2023] [Indexed: 09/09/2023] Open
Abstract
Prion diseases are prototype of infectious diseases transmitted by a protein, the prion protein (PrP), and are still not understandable at the molecular level. Heterogenous species of aggregated PrP can be generated from its monomer. α-synuclein (αSyn), related to Parkinson's disease, has also shown a prion-like pathogenic character, and likewise PrP interacts with nucleic acids (NAs), which in turn modulate their aggregation. Recently, our group and others have characterized that NAs and/or RNA-binding proteins (RBPs) modulate recombinant PrP and/or αSyn condensates formation, and uncontrolled condensation might precede pathological aggregation. Tackling abnormal phase separation of neurodegenerative disease-related proteins has been proposed as a promising therapeutic target. Therefore, understanding the mechanism by which polyanions, like NAs, modulate phase transitions intracellularly, is key to assess their role on toxicity promotion and neuronal death. Herein we discuss data on the nucleic acids binding properties and phase separation ability of PrP and αSyn with a special focus on their modulation by NAs and RBPs. Furthermore, we provide insights into condensation of PrP and/or αSyn in the light of non-trivial subcellular locations such as the nuclear and cytosolic environments.
Collapse
Affiliation(s)
- Yraima Cordeiro
- Faculty of Pharmacy, Universidade Federal do Rio de Janeiro, Av Carlos Chagas Filho 373, bloco B, subsolo Sala 36, Rio de Janeiro, RJ 21941-902 Brazil
| | - Maria Heloisa O. Freire
- Faculty of Pharmacy, Universidade Federal do Rio de Janeiro, Av Carlos Chagas Filho 373, bloco B, subsolo Sala 36, Rio de Janeiro, RJ 21941-902 Brazil
| | - Adalgisa Felippe Wiecikowski
- Faculty of Pharmacy, Universidade Federal do Rio de Janeiro, Av Carlos Chagas Filho 373, bloco B, subsolo Sala 36, Rio de Janeiro, RJ 21941-902 Brazil
| | - Mariana Juliani do Amaral
- Faculty of Pharmacy, Universidade Federal do Rio de Janeiro, Av Carlos Chagas Filho 373, bloco B, subsolo Sala 36, Rio de Janeiro, RJ 21941-902 Brazil
| |
Collapse
|
20
|
Yoshida T, Takenaka KI, Sakamoto H, Kojima Y, Sakano T, Shibayama K, Nakamura K, Hanawa-Suetsugu K, Mori Y, Hirabayashi Y, Hirose K, Takamori S. Compartmentalization of soluble endocytic proteins in synaptic vesicle clusters by phase separation. iScience 2023; 26:106826. [PMID: 37250768 PMCID: PMC10209458 DOI: 10.1016/j.isci.2023.106826] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 04/10/2023] [Accepted: 05/02/2023] [Indexed: 05/31/2023] Open
Abstract
Synaptic vesicle (SV) clusters, which reportedly result from synapsin's capacity to undergo liquid-liquid phase separation (LLPS), constitute the structural basis for neurotransmission. Although these clusters contain various endocytic accessory proteins, how endocytic proteins accumulate in SV clusters remains unknown. Here, we report that endophilin A1 (EndoA1), the endocytic scaffold protein, undergoes LLPS under physiologically relevant concentrations at presynaptic terminals. On heterologous expression, EndoA1 facilitates the formation of synapsin condensates and accumulates in SV-like vesicle clusters via synapsin. Moreover, EndoA1 condensates recruit endocytic proteins such as dynamin 1, amphiphysin, and intersectin 1, none of which are recruited in vesicle clusters by synapsin. In cultured neurons, like synapsin, EndoA1 is compartmentalized in SV clusters through LLPS, exhibiting activity-dependent dispersion/reassembly cycles. Thus, beyond its essential function in SV endocytosis, EndoA1 serves an additional structural function by undergoing LLPS, thereby accumulating various endocytic proteins in dynamic SV clusters in concert with synapsin.
Collapse
Affiliation(s)
- Tomofumi Yoshida
- Laboratory of Neural Membrane Biology, Graduate School of Brain Science, Doshisha University, Kyoto 610-0394, Japan
| | - Koh-ichiro Takenaka
- Laboratory of Neural Membrane Biology, Graduate School of Brain Science, Doshisha University, Kyoto 610-0394, Japan
| | - Hirokazu Sakamoto
- Department of Pharmacology, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan
| | - Yusuke Kojima
- Department of Pharmacology, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan
| | - Takumi Sakano
- Department of Chemistry and Biotechnology, School of Engineering, The University of Tokyo, Tokyo 113-0033, Japan
| | - Koyo Shibayama
- Department of Chemistry and Biotechnology, School of Engineering, The University of Tokyo, Tokyo 113-0033, Japan
| | - Koki Nakamura
- Department of Chemistry and Biotechnology, School of Engineering, The University of Tokyo, Tokyo 113-0033, Japan
| | - Kyoko Hanawa-Suetsugu
- Laboratory of Neural Membrane Biology, Graduate School of Brain Science, Doshisha University, Kyoto 610-0394, Japan
| | - Yasunori Mori
- Laboratory of Neural Membrane Biology, Graduate School of Brain Science, Doshisha University, Kyoto 610-0394, Japan
| | - Yusuke Hirabayashi
- Department of Chemistry and Biotechnology, School of Engineering, The University of Tokyo, Tokyo 113-0033, Japan
| | - Kenzo Hirose
- Department of Pharmacology, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan
- International Research Center for Neurointelligence (WPI-IRCN), The University of Tokyo, Tokyo 113-0033, Japan
| | - Shigeo Takamori
- Laboratory of Neural Membrane Biology, Graduate School of Brain Science, Doshisha University, Kyoto 610-0394, Japan
| |
Collapse
|
21
|
Sansevrino R, Hoffmann C, Milovanovic D. Condensate biology of synaptic vesicle clusters. Trends Neurosci 2023; 46:293-306. [PMID: 36725404 DOI: 10.1016/j.tins.2023.01.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 12/20/2022] [Accepted: 01/10/2023] [Indexed: 01/31/2023]
Abstract
Neuronal communication crucially relies on exocytosis of neurotransmitters from synaptic vesicles (SVs) which are clustered at synapses. To ensure reliable neurotransmitter release, synapses need to maintain an adequate pool of SVs at all times. Decades of research have established that SVs are clustered by synapsin 1, an abundant SV-associated phosphoprotein. The classical view postulates that SVs are crosslinked in a scaffold of protein-protein interactions between synapsins and their binding partners. Recent studies have shown that synapsins cluster SVs via liquid-liquid phase separation (LLPS), thus providing a new framework for the organization of the synapse. We discuss the evidence for phase separation of SVs, emphasizing emerging questions related to its regulation, specificity, and reversibility.
Collapse
Affiliation(s)
- Roberto Sansevrino
- Laboratory of Molecular Neuroscience, German Center for Neurodegenerative Diseases (DZNE), 10117 Berlin, Germany
| | - Christian Hoffmann
- Laboratory of Molecular Neuroscience, German Center for Neurodegenerative Diseases (DZNE), 10117 Berlin, Germany
| | - Dragomir Milovanovic
- Laboratory of Molecular Neuroscience, German Center for Neurodegenerative Diseases (DZNE), 10117 Berlin, Germany.
| |
Collapse
|
22
|
Nam J, Gwon Y. Neuronal biomolecular condensates and their implications in neurodegenerative diseases. Front Aging Neurosci 2023; 15:1145420. [PMID: 37065458 PMCID: PMC10102667 DOI: 10.3389/fnagi.2023.1145420] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 03/01/2023] [Indexed: 04/03/2023] Open
Abstract
Biomolecular condensates are subcellular organizations where functionally related proteins and nucleic acids are assembled through liquid-liquid phase separation, allowing them to develop on a larger scale without a membrane. However, biomolecular condensates are highly vulnerable to disruptions from genetic risks and various factors inside and outside the cell and are strongly implicated in the pathogenesis of many neurodegenerative diseases. In addition to the classical view of the nucleation-polymerization process that triggers the protein aggregation from the misfolded seed, the pathologic transition of biomolecular condensates can also promote the aggregation of proteins found in the deposits of neurodegenerative diseases. Furthermore, it has been suggested that several protein or protein-RNA complexes located in the synapse and along the neuronal process are neuron-specific condensates displaying liquid-like properties. As their compositional and functional modifications play a crucial role in the context of neurodegeneration, further research is needed to fully understand the role of neuronal biomolecular condensates. In this article, we will discuss recent findings that explore the pivotal role of biomolecular condensates in the development of neuronal defects and neurodegeneration.
Collapse
Affiliation(s)
| | - Youngdae Gwon
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
| |
Collapse
|
23
|
Boeynaems S, Chong S, Gsponer J, Holt L, Milovanovic D, Mitrea DM, Mueller-Cajar O, Portz B, Reilly JF, Reinkemeier CD, Sabari BR, Sanulli S, Shorter J, Sontag E, Strader L, Stachowiak J, Weber SC, White M, Zhang H, Zweckstetter M, Elbaum-Garfinkle S, Kriwacki R. Phase Separation in Biology and Disease; Current Perspectives and Open Questions. J Mol Biol 2023; 435:167971. [PMID: 36690068 PMCID: PMC9970028 DOI: 10.1016/j.jmb.2023.167971] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 01/12/2023] [Accepted: 01/13/2023] [Indexed: 01/22/2023]
Abstract
In the past almost 15 years, we witnessed the birth of a new scientific field focused on the existence, formation, biological functions, and disease associations of membraneless bodies in cells, now referred to as biomolecular condensates. Pioneering studies from several laboratories [reviewed in1-3] supported a model wherein biomolecular condensates associated with diverse biological processes form through the process of phase separation. These and other findings that followed have revolutionized our understanding of how biomolecules are organized in space and time within cells to perform myriad biological functions, including cell fate determination, signal transduction, endocytosis, regulation of gene expression and protein translation, and regulation of RNA metabolism. Further, condensates formed through aberrant phase transitions have been associated with numerous human diseases, prominently including neurodegeneration and cancer. While in some cases, rigorous evidence supports links between formation of biomolecular condensates through phase separation and biological functions, in many others such links are less robustly supported, which has led to rightful scrutiny of the generality of the roles of phase separation in biology and disease.4-7 During a week-long workshop in March 2022 at the Telluride Science Research Center (TSRC) in Telluride, Colorado, ∼25 scientists addressed key questions surrounding the biomolecular condensates field. Herein, we present insights gained through these discussions, addressing topics including, roles of condensates in diverse biological processes and systems, and normal and disease cell states, their applications to synthetic biology, and the potential for therapeutically targeting biomolecular condensates.
Collapse
Affiliation(s)
- Steven Boeynaems
- Department of Molecular and Human Genetics, Therapeutic Innovation Center (THINC), Center for Alzheimer’s and Neurodegenerative Diseases (CAND), Dan L Duncan Comprehensive Cancer Center (DLDCCC), Baylor College of Medicine, Houston, TX 77030, USA and Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, TX 77030, USA
| | - Shasha Chong
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125
| | - Jörg Gsponer
- Michael Smith Laboratories, Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, Canada
| | - Liam Holt
- New York University School of Medicine, Institute for Systems Genetics, New York, NY 10016
| | - Drago Milovanovic
- Laboratory of Molecular Neuroscience, German Center for Neurodegenerative Diseases (DZNE), 10117 Berlin, Germany
| | | | - Oliver Mueller-Cajar
- School of Biological Sciences, Nanyang Technological University, Singapore 637551
| | | | | | | | - Benjamin R. Sabari
- Laboratory of Nuclear Organization, Cecil H. and Ida Green Center for Reproductive Biology Sciences, University of Texas Southwestern Medical Center, Dallas, TX
| | - Serena Sanulli
- Department of Genetics, Stanford University, Palo Alto, CA 94304
| | - James Shorter
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Emily Sontag
- Department of Biological Sciences, Marquette University, Milwaukee, Wisconsin
| | - Lucia Strader
- Department of Biology, Duke University, Durham, NC 27708 USA
| | - Jeanne Stachowiak
- University of Texas at Austin, Department of Biomedical Engineering, Austin, TX, USA
| | | | | | - Huaiying Zhang
- Department of Biological Sciences, Mellon College of Science, Carnegie Mellon University, Pittsburgh, PA 15213
| | - Markus Zweckstetter
- German Center for Neurodegenerative Diseases (DZNE), Von-Siebold-Str. 3a, 37075 Göttingen, Germany; Max Planck Institute for Multidisciplinary Sciences, Department of NMR-based Structural Biology, Am Fassberg 11, 37077 Göttingen, Germany
| | - Shana Elbaum-Garfinkle
- Department of Biochemistry, The Graduate Center of the City University of New York, New York, NY and Structural Biology Initiative, Advanced Science Research Center, City University of New York, New York, NY
| | - Richard Kriwacki
- Department of Structural Biology, St. Jude Children’s Research Hospital, Memphis, Tennessee and Department of Microbiology, Immunology and Biochemistry, University of Tennessee Health Sciences Center, Memphis, Tennessee
| |
Collapse
|
24
|
Sharma M, Burré J. α-Synuclein in synaptic function and dysfunction. Trends Neurosci 2023; 46:153-166. [PMID: 36567199 PMCID: PMC9877183 DOI: 10.1016/j.tins.2022.11.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 11/07/2022] [Accepted: 11/29/2022] [Indexed: 12/24/2022]
Abstract
α-Synuclein is a neuronal protein that is enriched in presynaptic terminals. Under physiological conditions, it binds to synaptic vesicle membranes and functions in neurotransmitter release, although the molecular details remain unclear, and it is controversial whether α-synuclein inhibits or facilitates neurotransmitter release. Pathologically, in synucleinopathies including Parkinson's disease (PD), α-synuclein forms aggregates that recruit monomeric α-synuclein and spread throughout the brain, which triggers neuronal dysfunction at molecular, cellular, and organ levels. Here, we present an overview of the effects of α-synuclein on SNARE-complex assembly, neurotransmitter release, and synaptic vesicle pool homeostasis, and discuss how the observed divergent effects of α-synuclein on neurotransmitter release can be reconciled. We also discuss how gain-of-function versus loss-of-function of α-synuclein may contribute to pathogenesis in synucleinopathies.
Collapse
Affiliation(s)
- Manu Sharma
- Appel Alzheimer's Disease Research Institute, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA.
| | - Jacqueline Burré
- Appel Alzheimer's Disease Research Institute, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA.
| |
Collapse
|
25
|
Liquid-liquid Phase Separation of α-Synuclein: A New Mechanistic Insight for α-Synuclein Aggregation Associated with Parkinson's Disease Pathogenesis. J Mol Biol 2023; 435:167713. [PMID: 35787838 DOI: 10.1016/j.jmb.2022.167713] [Citation(s) in RCA: 36] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2022] [Revised: 06/25/2022] [Accepted: 06/27/2022] [Indexed: 02/04/2023]
Abstract
Aberrant aggregation of the misfolded presynaptic protein, α-Synuclein (α-Syn) into Lewy body (LB) and Lewy neuritis (LN) is a major pathological hallmark of Parkinson's disease (PD) and other synucleinopathies. Numerous studies have suggested that prefibrillar and fibrillar species of the misfolded α-Syn aggregates are responsible for cell death in PD pathogenesis. However, the precise molecular events during α-Syn aggregation, especially in the early stages, remain elusive. Emerging evidence has demonstrated that liquid-liquid phase separation (LLPS) of α-Syn occurs in the nucleation step of α-Syn aggregation, which offers an alternate non-canonical aggregation pathway in the crowded microenvironment. The liquid-like α-Syn droplets gradually undergo an irreversible liquid-to-solid phase transition into amyloid-like hydrogel entrapping oligomers and fibrils. This new mechanism of α-Syn LLPS and gel formation might represent the molecular basis of cellular toxicity associated with PD. This review aims to demonstrate the recent development of α-Syn LLPS, the underlying mechanism along with the microscopic events of aberrant phase transition. This review further discusses how several intrinsic and extrinsic factors regulate the thermodynamics and kinetics of α-Syn LLPS and co-LLPS with other proteins, which might explain the pathophysiology of α-Syn in various neurodegenerative diseases.
Collapse
|
26
|
Wu X, Qiu H, Zhang M. Interactions between Membraneless Condensates and Membranous Organelles at the Presynapse: A Phase Separation View of Synaptic Vesicle Cycle. J Mol Biol 2023; 435:167629. [PMID: 35595170 DOI: 10.1016/j.jmb.2022.167629] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 05/03/2022] [Accepted: 05/04/2022] [Indexed: 02/04/2023]
Abstract
Action potential-induced neurotransmitter release in presynaptic boutons involves coordinated actions of a large list of proteins that are associated directly or indirectly with membrane structures including synaptic vesicles and plasma membranes. These proteins are often highly abundant in different synaptic bouton sub-compartments, and they rarely act alone. Instead, these proteins interact with each other forming intricate and distinct molecular complexes. Many of these complexes form condensed clusters on membrane surfaces. This review summarizes findings in recent years showing that many of presynaptic protein complex assemblies are formed via phase separation. These protein condensates extensively interact with lipid membranes via distinct modes, forming various mesoscale structures by different mode of organizations between membraneless condensates and membranous organelles. We discuss that such mesoscale interactions could have deep implications on mobilization, exocytosis, and retrieval of synaptic vesicles.
Collapse
Affiliation(s)
- Xiandeng Wu
- Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Hua Qiu
- Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Mingjie Zhang
- Greater Bay Biomedical Innocenter, Shenzhen Bay Laboratory, Shenzhen 518036, China; School of Life Sciences, Southern University of Science and Technology, Shenzhen 518055, China.
| |
Collapse
|
27
|
Gao V, Briano JA, Komer LE, Burré J. Functional and Pathological Effects of α-Synuclein on Synaptic SNARE Complexes. J Mol Biol 2023; 435:167714. [PMID: 35787839 PMCID: PMC10472340 DOI: 10.1016/j.jmb.2022.167714] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2022] [Revised: 06/24/2022] [Accepted: 06/27/2022] [Indexed: 02/07/2023]
Abstract
α-Synuclein is an abundant protein at the neuronal synapse that has been implicated in Parkinson's disease for over 25 years and characterizes the hallmark pathology of a group of neurodegenerative diseases now known as the synucleinopathies. Physiologically, α-synuclein exists in an equilibrium between a synaptic vesicle membrane-bound α-helical multimer and a cytosolic largely unstructured monomer. Through its membrane-bound state, α-synuclein functions in neurotransmitter release by modulating several steps in the synaptic vesicle cycle, including synaptic vesicle clustering and docking, SNARE complex assembly, and homeostasis of synaptic vesicle pools. These functions have been ascribed to α-synuclein's interactions with the synaptic vesicle SNARE protein VAMP2/synaptobrevin-2, the synaptic vesicle-attached synapsins, and the synaptic vesicle membrane itself. How α-synuclein affects these processes, and whether disease is due to loss-of-function or gain-of-toxic-function of α-synuclein remains unclear. In this review, we provide an in-depth summary of the existing literature, discuss possible reasons for the discrepancies in the field, and propose a working model that reconciles the findings in the literature.
Collapse
Affiliation(s)
- Virginia Gao
- Appel Alzheimer's Disease Research Institute & Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA; Department of Neurology, New York Presbyterian/Weill Cornell Medicine, New York, NY, USA.
| | - Juan A Briano
- Appel Alzheimer's Disease Research Institute & Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
| | - Lauren E Komer
- Appel Alzheimer's Disease Research Institute & Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA. https://www.twitter.com/lauren_komer
| | - Jacqueline Burré
- Appel Alzheimer's Disease Research Institute & Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA.
| |
Collapse
|
28
|
The Role of Membrane Affinity and Binding Modes in Alpha-Synuclein Regulation of Vesicle Release and Trafficking. Biomolecules 2022; 12:biom12121816. [PMID: 36551244 PMCID: PMC9775087 DOI: 10.3390/biom12121816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 11/02/2022] [Accepted: 11/27/2022] [Indexed: 12/12/2022] Open
Abstract
Alpha-synuclein is a presynaptic protein linked to Parkinson's disease with a poorly characterized physiological role in regulating the synaptic vesicle cycle. Using RBL-2H3 cells as a model system, we earlier reported that wild-type alpha-synuclein can act as both an inhibitor and a potentiator of stimulated exocytosis in a concentration-dependent manner. The inhibitory function is constitutive and depends on membrane binding by the helix-2 region of the lipid-binding domain, while potentiation becomes apparent only at high concentrations. Using structural and functional characterization of conformationally selective mutants via a combination of spectroscopic and cellular assays, we show here that binding affinity for isolated vesicles similar in size to synaptic vesicles is a primary determinant of alpha-synuclein-mediated potentiation of vesicle release. Inhibition of release is sensitive to changes in the region linking the helix-1 and helix-2 regions of the N-terminal lipid-binding domain and may require some degree of coupling between these regions. Potentiation of release likely occurs as a result of alpha-synuclein interactions with undocked vesicles isolated away from the active zone in internal pools. Consistent with this, we observe that alpha-synuclein can disperse vesicles from in vitro clusters organized by condensates of the presynaptic protein synapsin-1.
Collapse
|
29
|
Phase separation and other forms of α-Synuclein self-assemblies. Essays Biochem 2022; 66:987-1000. [DOI: 10.1042/ebc20220055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 10/21/2022] [Accepted: 10/24/2022] [Indexed: 11/16/2022]
Abstract
Abstract
α-Synuclein (α-Syn) is a natively unstructured protein, which self-assembles into higher-order aggregates possessing serious pathophysiological implications. α-Syn aberrantly self-assembles into protein aggregates, which have been widely implicated in Parkinson’s disease (PD) pathogenesis and other synucleinopathies. The self-assembly of α-Syn involves the structural conversion of soluble monomeric protein into oligomeric intermediates and eventually fibrillar aggregates of amyloids with cross-β-sheet rich conformation. These aggregated α-Syn species majorly constitute the intraneuronal inclusions, which is a hallmark of PD neuropathology. Self-assembly/aggregation of α-Syn is not a single-state conversion process as unfolded protein can access multiple conformational states through the formation of metastable, transient pre-fibrillar intermediate species. Recent studies have indicated that soluble oligomers are the potential neurotoxic species responsible for cell death in PD pathogenesis. The heterogeneous and transient nature of oligomers formed during the early stage of aggregation pathway limit their detailed study in understanding the structure–toxicity relationship. Moreover, the precise molecular events occurring in the early stage of α-Syn aggregation process majorly remain unsolved. Recently, liquid–liquid phase separation (LLPS) of α-Syn has been designated as an alternate nucleation mechanism, which occurs in the early lag phase of the aggregation pathway leading to the formation of dynamic supramolecular assemblies. The stronger self-association among the protein molecules triggers the irreversible liquid-to-solid transition of these supramolecular assemblies into the amyloid-like hydrogel, which may serve as a reservoir entrapping toxic oligomeric intermediates and fibrils. This review strives to provide insights into different modes of α-Syn self-assemblies including LLPS-mediated self-assembly and its recent advancements.
Collapse
|
30
|
Shillcock JC, Lagisquet C, Alexandre J, Vuillon L, Ipsen JH. Model biomolecular condensates have heterogeneous structure quantitatively dependent on the interaction profile of their constituent macromolecules. SOFT MATTER 2022; 18:6674-6693. [PMID: 36004748 DOI: 10.1039/d2sm00387b] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Biomolecular condensates play numerous roles in cells by selectively concentrating client proteins while excluding others. These functions are likely to be sensitive to the spatial organization of the scaffold proteins forming the condensate. We use coarse-grained molecular simulations to show that model intrinsically-disordered proteins phase separate into a heterogeneous, structured fluid characterized by a well-defined length scale. The proteins are modelled as semi-flexible polymers with punctate, multifunctional binding sites in good solvent conditions. Their dense phase is highly solvated with a spatial structure that is more sensitive to the separation of the binding sites than their affinity. We introduce graph theoretic measures to quantify their heterogeneity, and find that it increases with increasing binding site number, and exhibits multi-timescale dynamics. The model proteins also swell on passing from the dilute solution to the dense phase. The simulations predict that the structure of the dense phase is modulated by the location and affinity of binding sites distant from the termini of the proteins, while sites near the termini more strongly affect its phase behaviour. The relations uncovered between the arrangement of weak interaction sites on disordered proteins and the material properties of their dense phase can be experimentally tested to give insight into the biophysical properties, pathological effects, and rational design of biomolecular condensates.
Collapse
Affiliation(s)
- Julian C Shillcock
- Blue Brain Project and Laboratory of Molecular and Chemical Biology of Neurodegeneration, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.
| | - Clément Lagisquet
- LAMA, Univ. Savoie Mont Blanc, CNRS, LAMA, 73376 Le Bourget du Lac, France.
| | - Jérémy Alexandre
- Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Laurent Vuillon
- LAMA, Univ. Savoie Mont Blanc, CNRS, LAMA, 73376 Le Bourget du Lac, France.
| | - John H Ipsen
- Dept. of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| |
Collapse
|
31
|
Xu B, Chen J, Liu Y. Curcumin Interacts with α-Synuclein Condensates To Inhibit Amyloid Aggregation under Phase Separation. ACS OMEGA 2022; 7:30281-30290. [PMID: 36061735 PMCID: PMC9434619 DOI: 10.1021/acsomega.2c03534] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Accepted: 08/03/2022] [Indexed: 05/27/2023]
Abstract
The amyloid aggregation of α-synuclein (α-Syn) is highly associated with Parkinson's disease (PD). Discovering α-Syn amyloid inhibitors is one of the strategies for PD therapies. Recent studies suggested that α-Syn undergoes phase separation to accelerate amyloid aggregation. Molecules modulating α-Syn phase separation or transition have the potential to regulate amyloid aggregation. Here, we discovered that curcumin, a small natural molecule, interacts with α-Syn during phase separation. Our study showed that curcumin neither affects the formation of α-Syn condensates nor influences the initial morphology of α-Syn condensates. However, curcumin decreases the fluidity of α-Syn inside the condensates and efficiently inhibits α-Syn from turning into an amyloid. It also inhibits the amyloid aggregations of PD disease-related α-Syn E46K and H50Q mutants under phase separation. Furthermore, curcumin can destabilize preformed α-Syn amyloid aggregates in the condensates. Together, our findings demonstrate that curcumin regulates α-Syn amyloid formation during protein phase separation and reveal that α-Syn amyloid aggregation under phase separation can be modulated by small molecules.
Collapse
|
32
|
The Effect of Aggregated Alpha Synuclein on Synaptic and Axonal Proteins in Parkinson’s Disease—A Systematic Review. Biomolecules 2022; 12:biom12091199. [PMID: 36139038 PMCID: PMC9496556 DOI: 10.3390/biom12091199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 08/22/2022] [Accepted: 08/26/2022] [Indexed: 11/17/2022] Open
Abstract
α-synuclein is a core component of Lewy bodies, one of the pathological hallmarks of Parkinson’s disease. Aggregated α-synuclein can impair both synaptic functioning and axonal transport. However, understanding the pathological role that α-synuclein plays at a cellular level is complicated as existing findings are multifaceted and dependent on the mutation, the species, and the quantity of the protein that is involved. This systematic review aims to stratify the research findings to develop a more comprehensive understanding of the role of aggregated α-synuclein on synaptic and axonal proteins in Parkinson’s disease models. A literature search of the PubMed, Scopus, and Web of Science databases was conducted and a total of 39 studies were included for analysis. The review provides evidence for the dysregulation or redistribution of synaptic and axonal proteins due to α-synuclein toxicity. However, due to the high quantity of variables that were used in the research investigations, it was challenging to ascertain exactly what effect α-synuclein has on the expression of the proteins. A more standardized experimental approach regarding the variables that are employed in future studies is crucial so that existing literature can be consolidated. New research involving aggregated α-synuclein at the synapse and regarding axonal transport could be advantageous in guiding new treatment solutions.
Collapse
|
33
|
Molecular and Functional Interactions of Alpha-Synuclein with Rab3a. J Biol Chem 2022; 298:102239. [PMID: 35809645 PMCID: PMC9396396 DOI: 10.1016/j.jbc.2022.102239] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 07/01/2022] [Accepted: 07/04/2022] [Indexed: 11/23/2022] Open
Abstract
Alpha-synuclein (a-Syn) is a presynaptic protein, the misfolding of which is associated with Parkinson’s disease. Rab GTPases are small guanine nucleotide binding proteins that play key roles in vesicle trafficking and have been associated with a-Syn function and dysfunction. a-Syn is enriched on synaptic vesicles, where it has been reported to interact with GTP-bound Rab3a, a master regulator of synaptic vesicle trafficking. a-Syn is known to bind weakly to Rab8a in solution via a positively charged patch, but the physiological implications of such interactions have not been explored. Here, we investigate direct interactions between a-Syn and Rab3a in solution and on lipid membranes using NMR spectroscopy. We find that the C terminus of a-Syn interacts with Rab3a in a manner similar to its previously reported interaction with Rab8a. While weak in solution, we demonstrate that this interaction becomes stronger when the proteins are bound to a membrane surface. The Rab3a binding site for a-Syn is similar to the surface that contacts the Rab3a effector rabphilin-3A, which modulates the enzymatic activity of Rab3a. Accordingly, we show that a-Syn inhibits GTP hydrolysis by Rab3a and that inhibition is more potent on the membrane surface, suggesting that their interaction may be functionally relevant. Finally, we show that phosphorylation of a-Syn residue Ser 129, a modification associated with Parkinson’s disease pathology, enhances its interactions with Rab3a and increases its ability to inhibit Rab3a GTP hydrolysis. These results represent the first observation of a functional role for synuclein-Rab interactions and for a-Syn Ser 129 phosphorylation.
Collapse
|
34
|
Milovanovic D, Rizzoli SO. Editorial: Protein Phase Separation and Aggregation in (Patho)Physiology of Neurons. Front Physiol 2022; 13:959570. [PMID: 35860657 PMCID: PMC9289605 DOI: 10.3389/fphys.2022.959570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 06/13/2022] [Indexed: 11/13/2022] Open
Affiliation(s)
- Dragomir Milovanovic
- Laboratory of Molecular Neuroscience, German Center for Neurodegenerative Diseases, Berlin, Germany
- *Correspondence: Dragomir Milovanovic, ; Silvio O. Rizzoli,
| | - Silvio O. Rizzoli
- Institute of Neuro- and Sensory Physiology, University Medical Center Göttingen, Göttingen, Germany
- *Correspondence: Dragomir Milovanovic, ; Silvio O. Rizzoli,
| |
Collapse
|
35
|
Freitag K, Sterczyk N, Wendlinger S, Obermayer B, Schulz J, Farztdinov V, Mülleder M, Ralser M, Houtman J, Fleck L, Braeuning C, Sansevrino R, Hoffmann C, Milovanovic D, Sigrist SJ, Conrad T, Beule D, Heppner FL, Jendrach M. Spermidine reduces neuroinflammation and soluble amyloid beta in an Alzheimer's disease mouse model. J Neuroinflammation 2022; 19:172. [PMID: 35780157 PMCID: PMC9250727 DOI: 10.1186/s12974-022-02534-7] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 06/16/2022] [Indexed: 12/27/2022] Open
Abstract
Background Deposition of amyloid beta (Aβ) and hyperphosphorylated tau along with glial cell-mediated neuroinflammation are prominent pathogenic hallmarks of Alzheimer’s disease (AD). In recent years, impairment of autophagy has been identified as another important feature contributing to AD progression. Therefore, the potential of the autophagy activator spermidine, a small body-endogenous polyamine often used as dietary supplement, was assessed on Aβ pathology and glial cell-mediated neuroinflammation. Results Oral treatment of the amyloid prone AD-like APPPS1 mice with spermidine reduced neurotoxic soluble Aβ and decreased AD-associated neuroinflammation. Mechanistically, single nuclei sequencing revealed AD-associated microglia to be the main target of spermidine. This microglia population was characterized by increased AXL levels and expression of genes implicated in cell migration and phagocytosis. A subsequent proteome analysis of isolated microglia confirmed the anti-inflammatory and cytoskeletal effects of spermidine in APPPS1 mice. In primary microglia and astrocytes, spermidine-induced autophagy subsequently affected TLR3- and TLR4-mediated inflammatory processes, phagocytosis of Aβ and motility. Interestingly, spermidine regulated the neuroinflammatory response of microglia beyond transcriptional control by interfering with the assembly of the inflammasome. Conclusions Our data highlight that the autophagy activator spermidine holds the potential to enhance Aβ degradation and to counteract glia-mediated neuroinflammation in AD pathology. Supplementary Information The online version contains supplementary material available at 10.1186/s12974-022-02534-7.
Collapse
Affiliation(s)
- Kiara Freitag
- Department of Neuropathology, Charité, Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität Zu Berlin, Berlin Institute of Health, Berlin, Germany.,German Center for Neurodegenerative Diseases (DZNE) within the Helmholtz Association, Berlin, Germany
| | - Nele Sterczyk
- Department of Neuropathology, Charité, Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität Zu Berlin, Berlin Institute of Health, Berlin, Germany
| | - Sarah Wendlinger
- Department of Neuropathology, Charité, Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität Zu Berlin, Berlin Institute of Health, Berlin, Germany.,Department of Biosciences, University of Salzburg, Salzburg, Austria
| | - Benedikt Obermayer
- Core Unit Bioinformatics, Berlin Institute of Health at Charité, Universitätsmedizin Berlin, Charitéplatz 1, Berlin, Germany
| | - Julia Schulz
- Department of Neuropathology, Charité, Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität Zu Berlin, Berlin Institute of Health, Berlin, Germany
| | - Vadim Farztdinov
- Core Facility, High-Throughput Mass Spectrometry, Charité, Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität Zu Berlin, Berlin, Germany
| | - Michael Mülleder
- Core Facility, High-Throughput Mass Spectrometry, Charité, Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität Zu Berlin, Berlin, Germany
| | - Markus Ralser
- Molecular Biology of Metabolism Laboratory, The Francis Crick Institute, London, UK.,Department of Biochemistry, Charité, Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität Zu Berlin, Berlin, Germany
| | - Judith Houtman
- Department of Neuropathology, Charité, Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität Zu Berlin, Berlin Institute of Health, Berlin, Germany
| | - Lara Fleck
- Department of Neuropathology, Charité, Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität Zu Berlin, Berlin Institute of Health, Berlin, Germany
| | - Caroline Braeuning
- Genomics Technology Platform, Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany.,Berlin Institute of Health (BIH), Berlin, Germany
| | - Roberto Sansevrino
- Laboratory of Molecular Neuroscience, German Center for Neurodegenerative Diseases (DZNE) within the Helmholtz Association, Berlin, Germany
| | - Christian Hoffmann
- Laboratory of Molecular Neuroscience, German Center for Neurodegenerative Diseases (DZNE) within the Helmholtz Association, Berlin, Germany
| | - Dragomir Milovanovic
- Laboratory of Molecular Neuroscience, German Center for Neurodegenerative Diseases (DZNE) within the Helmholtz Association, Berlin, Germany
| | - Stephan J Sigrist
- German Center for Neurodegenerative Diseases (DZNE) within the Helmholtz Association, Berlin, Germany.,Cluster of Excellence, NeuroCure, Berlin, Germany.,Institute for Biology and Genetics, Freie Universität Berlin, Berlin, Germany
| | - Thomas Conrad
- Genomics Technology Platform, Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany.,Berlin Institute of Health (BIH), Berlin, Germany
| | - Dieter Beule
- Core Unit Bioinformatics, Berlin Institute of Health at Charité, Universitätsmedizin Berlin, Charitéplatz 1, Berlin, Germany
| | - Frank L Heppner
- Department of Neuropathology, Charité, Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität Zu Berlin, Berlin Institute of Health, Berlin, Germany.,German Center for Neurodegenerative Diseases (DZNE) within the Helmholtz Association, Berlin, Germany.,Cluster of Excellence, NeuroCure, Berlin, Germany
| | - Marina Jendrach
- Department of Neuropathology, Charité, Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität Zu Berlin, Berlin Institute of Health, Berlin, Germany.
| |
Collapse
|
36
|
Xu B, Mo X, Chen J, Yu H, Liu Y. Myricetin Inhibits α-Synuclein Amyloid Aggregation by Delaying the Liquid-to-Solid Phase Transition. Chembiochem 2022; 23:e202200216. [PMID: 35657723 DOI: 10.1002/cbic.202200216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2022] [Revised: 06/02/2022] [Indexed: 11/12/2022]
Abstract
The aggregation of α-synuclein (α-Syn) is a critical pathological hallmark of Parkinson's disease (PD). Prevention of α-Syn aggregation has become a key strategy for treating PD. Recent studies have suggested that α-Syn undergoes liquid-liquid phase separation (LLPS) to facilitate nucleation and amyloid formation. Here, we examined the modulation of α-Syn aggregation by myricetin, a polyhydroxyflavonol compound, under the conditions of LLPS. Unexpectedly, neither the initial morphology nor the phase-separated fraction of α-Syn was altered by myricetin. However, the dynamics of α-Syn condensates decreased upon myricetin binding. Further studies showed that myricetin dose-dependently inhibits amyloid aggregation in the condensates by delaying the liquid-to-solid phase transition. In addition, myricetin could disassemble the preformed α-Syn amyloid aggregates matured from the condensates. Together, our study shows that myricetin inhibits α-Syn amyloid aggregation in the condensates by retarding the liquid-to-solid phase transition and reveals that α-Syn phase transition can be targeted to inhibit amyloid aggregation.
Collapse
Affiliation(s)
- Bingkuan Xu
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, No. 1 Wenyuan Road, Nanjing, 210046, (P. R. China)
| | - Xiaoli Mo
- Biology Department, Clark University 950 Main Street, Worcester, Massachusetts (USA) 01610
| | - Jing Chen
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, No. 1 Wenyuan Road, Nanjing, 210046, (P. R. China)
| | - Haijia Yu
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, No. 1 Wenyuan Road, Nanjing, 210046, (P. R. China)
| | - Yinghui Liu
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, No. 1 Wenyuan Road, Nanjing, 210046, (P. R. China)
| |
Collapse
|
37
|
Brodin L, Milovanovic D, Rizzoli SO, Shupliakov O. α-Synuclein in the Synaptic Vesicle Liquid Phase: Active Player or Passive Bystander? Front Mol Biosci 2022; 9:891508. [PMID: 35664678 PMCID: PMC9159372 DOI: 10.3389/fmolb.2022.891508] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Accepted: 04/26/2022] [Indexed: 12/15/2022] Open
Abstract
The protein α-synuclein, which is well-known for its links to Parkinson’s Disease, is associated with synaptic vesicles (SVs) in nerve terminals. Despite intensive studies, its precise physiological function remains elusive. Accumulating evidence indicates that liquid-liquid phase separation takes part in the assembly and/or maintenance of different synaptic compartments. The current review discusses recent data suggesting α-synuclein as a component of the SV liquid phase. We also consider possible implications of these data for disease.
Collapse
Affiliation(s)
- Lennart Brodin
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
- *Correspondence: Lennart Brodin, ; Oleg Shupliakov,
| | - Dragomir Milovanovic
- Laboratory of Molecular Neuroscience, German Center for Neurodegenerative Diseases (DZNE), Berlin, Germany
| | - Silvio O. Rizzoli
- Institute of Neuro- and Sensory Physiology, University Medical Center Göttingen, Göttingen, Germany
| | - Oleg Shupliakov
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
- Institute of Translational Biomedicine, St. Petersburg University, St. Petersburg, Russia
- *Correspondence: Lennart Brodin, ; Oleg Shupliakov,
| |
Collapse
|
38
|
Huang S, Mo X, Wang J, Ye X, Yu H, Liu Y. α-Synuclein phase separation and amyloid aggregation are modulated by C-terminal truncations. FEBS Lett 2022; 596:1388-1400. [PMID: 35485974 DOI: 10.1002/1873-3468.14361] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2022] [Revised: 04/10/2022] [Accepted: 04/16/2022] [Indexed: 11/11/2022]
Abstract
The aggregation of α-synuclein (α-Syn) is a key pathological hallmark of Parkinson's disease (PD). α-Syn undergoes liquid-liquid phase separation (LLPS) to drive amyloid aggregation. How the LLPS of α-Syn is regulated remains largely unknown. Here, we discovered that the C-terminal region modulates α-Syn phase separation through electrostatic interactions. The wild-type (WT) and PD disease-related truncated α-Syn can co-exist in the condensates. The truncated α-Syn could dramatically promote WT α-Syn phase separation. Further studies demonstrated that the truncated α-Syn accelerated WT α-Syn turning to amyloid aggregates by modulation of phase separation. Together, our findings disclose the role of the C-terminal domain in the LLPS of α-Syn and pave the path for understanding the mechanism of truncated α-Syn in PD pathology.
Collapse
Affiliation(s)
- Shuai Huang
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, 210023, China
| | - Xiaoli Mo
- Biology Department, Clark University, Worcester, Massachusetts, 01610, USA
| | - Jieyi Wang
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, 210023, China
| | - Xinyi Ye
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, 210023, China
| | - Haijia Yu
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, 210023, China
| | - Yinghui Liu
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, 210023, China
| |
Collapse
|
39
|
Huang S, Xu B, Liu Y. Calcium promotes α-synuclein liquid-liquid phase separation to accelerate amyloid aggregation. Biochem Biophys Res Commun 2022; 603:13-20. [PMID: 35276458 DOI: 10.1016/j.bbrc.2022.02.097] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 02/23/2022] [Indexed: 12/26/2022]
Abstract
α-Synuclein (α-Syn) is an aggregation-prone protein whose accumulation in Lewy bodies leads to neurodegenerative diseases like Parkinson's disease (PD). Calcium plays a critical role in neurons, and calcium dysregulation is one of the risk factors of PD. It is known that Ca2+ interacts with α-Syn and affects its assembly. However, how Ca2+ regulates α-Syn aggregation remains unclear. Here, we reported that Ca2+ accelerates α-Syn amyloid aggregation through the modulation of protein phase separation. We observed that Ca2+ promotes the formation of α-Syn liquid droplets but does not change the protein fluidity inside the droplets. Further studies showed Ca2+-involved α-Syn droplets are still able to fuse. A metal chelator eliminated Ca2+-induced enlargement of α-Syn droplets, suggesting the influence of Ca2+ on α-Syn assembly could be reversed at the stage of liquid-liquid phase separation (LLPS). Interestingly, our data showed Ca2+ still promoted α-Syn phase separation in the presence of the lipid membranes. In addition, Ca2+/α-syn droplets could efficiently recruit lipid vesicles to the surface of these condensates. Our findings demonstrate that Ca2+ facilitates α-Syn phase separation to accelerate amyloid aggregation and pave the path for understanding the implications of Ca2+ in α-Syn accumulation and PD.
Collapse
Affiliation(s)
- Shuai Huang
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, 210023, China
| | - Bingkuan Xu
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, 210023, China
| | - Yinghui Liu
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, 210023, China.
| |
Collapse
|
40
|
Milicevic K, Rankovic B, Andjus PR, Bataveljic D, Milovanovic D. Emerging Roles for Phase Separation of RNA-Binding Proteins in Cellular Pathology of ALS. Front Cell Dev Biol 2022; 10:840256. [PMID: 35372329 PMCID: PMC8965147 DOI: 10.3389/fcell.2022.840256] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 01/24/2022] [Indexed: 12/11/2022] Open
Abstract
Liquid-liquid phase separation (LLPS) is emerging as a major principle for the mesoscale organization of proteins, RNAs, and membrane-bound organelles into biomolecular condensates. These condensates allow for rapid cellular responses to changes in metabolic activities and signaling. Nowhere is this regulation more important than in neurons and glia, where cellular physiology occurs simultaneously on a range of time- and length-scales. In a number of neurodegenerative diseases, such as Amyotrophic Lateral Sclerosis (ALS), misregulation of biomolecular condensates leads to the formation of insoluble aggregates—a pathological hallmark of both sporadic and familial ALS. Here, we summarize how the emerging knowledge about the LLPS of ALS-related proteins corroborates with their aggregation. Understanding the mechanisms that lead to protein aggregation in ALS and how cells respond to these aggregates promises to open new directions for drug development.
Collapse
Affiliation(s)
- Katarina Milicevic
- Center for Laser Microscopy, Faculty of Biology, Institute of Physiology and Biochemistry “Ivan Djaja”, University of Belgrade, Belgrade, Serbia
| | - Branislava Rankovic
- Laboratory of Molecular Neuroscience, German Center for Neurodegenerative Diseases (DZNE), Berlin, Germany
| | - Pavle R. Andjus
- Center for Laser Microscopy, Faculty of Biology, Institute of Physiology and Biochemistry “Ivan Djaja”, University of Belgrade, Belgrade, Serbia
| | - Danijela Bataveljic
- Center for Laser Microscopy, Faculty of Biology, Institute of Physiology and Biochemistry “Ivan Djaja”, University of Belgrade, Belgrade, Serbia
- *Correspondence: Danijela Bataveljic, ; Dragomir Milovanovic,
| | - Dragomir Milovanovic
- Laboratory of Molecular Neuroscience, German Center for Neurodegenerative Diseases (DZNE), Berlin, Germany
- *Correspondence: Danijela Bataveljic, ; Dragomir Milovanovic,
| |
Collapse
|
41
|
Giampà M, Amundarain MJ, Herrera MG, Tonali N, Dodero VI. Implementing Complementary Approaches to Shape the Mechanism of α-Synuclein Oligomerization as a Model of Amyloid Aggregation. Molecules 2021; 27:88. [PMID: 35011320 PMCID: PMC8747028 DOI: 10.3390/molecules27010088] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 12/17/2021] [Accepted: 12/21/2021] [Indexed: 11/17/2022] Open
Abstract
The aggregation of proteins into amyloid fibers is linked to more than forty still incurable cellular and neurodegenerative diseases such as Parkinson's disease (PD), multiple system atrophy, Alzheimer's disease and type 2 diabetes, among others. The process of amyloid formation is a main feature of cell degeneration and disease pathogenesis. Despite being methodologically challenging, a complete understanding of the molecular mechanism of aggregation, especially in the early stages, is essential to find new biological targets for innovative therapies. Here, we reviewed selected examples on α-syn showing how complementary approaches, which employ different biophysical techniques and models, can better deal with a comprehensive study of amyloid aggregation. In addition to the monomer aggregation and conformational transition hypothesis, we reported new emerging theories regarding the self-aggregation of α-syn, such as the alpha-helix rich tetramer hypothesis, whose destabilization induce monomer aggregation; and the liquid-liquid phase separation hypothesis, which considers a phase separation of α-syn into liquid droplets as a primary event towards the evolution to aggregates. The final aim of this review is to show how multimodal methodologies provide a complete portrait of α-syn oligomerization and can be successfully extended to other protein aggregation diseases.
Collapse
Affiliation(s)
- Marco Giampà
- Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology, Olav Kyrres Gate 9, 7491 Trondheim, Norway;
| | - María J. Amundarain
- Instituto de Física del Sur (IFISUR), Departamento de Física, Universidad Nacional del Sur (UNS), CONICET, Av. L. N. Alem 1253, Bahía Blanca B8000CPB, Argentina;
| | - Maria Georgina Herrera
- Institute of Biochemistry and Pathobiochemistry, Ruhr University Bochum, 44801 Bochum, Germany;
| | - Nicolò Tonali
- BioCIS, CNRS, Faculté de Pharmacie, Université Paris-Saclay, 92290 Châtenay-Malabry, France
| | - Veronica I. Dodero
- Organic and Bioorganic Chemistry, Chemistry Department, Bielefeld University, Universitätstr. 25, 33615 Bielefeld, Germany
| |
Collapse
|
42
|
Fouke KE, Wegman ME, Weber SA, Brady EB, Román-Vendrell C, Morgan JR. Synuclein Regulates Synaptic Vesicle Clustering and Docking at a Vertebrate Synapse. Front Cell Dev Biol 2021; 9:774650. [PMID: 34901020 PMCID: PMC8660973 DOI: 10.3389/fcell.2021.774650] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2021] [Accepted: 11/10/2021] [Indexed: 11/17/2022] Open
Abstract
Neurotransmission relies critically on the exocytotic release of neurotransmitters from small synaptic vesicles (SVs) at the active zone. Therefore, it is essential for neurons to maintain an adequate pool of SVs clustered at synapses in order to sustain efficient neurotransmission. It is well established that the phosphoprotein synapsin 1 regulates SV clustering at synapses. Here, we demonstrate that synuclein, another SV-associated protein and synapsin binding partner, also modulates SV clustering at a vertebrate synapse. When acutely introduced to unstimulated lamprey reticulospinal synapses, a pan-synuclein antibody raised against the N-terminal domain of α-synuclein induced a significant loss of SVs at the synapse. Both docked SVs and the distal reserve pool of SVs were depleted, resulting in a loss of total membrane at synapses. In contrast, antibodies against two other abundant SV-associated proteins, synaptic vesicle glycoprotein 2 (SV2) and vesicle-associated membrane protein (VAMP/synaptobrevin), had no effect on the size or distribution of SV clusters. Synuclein perturbation caused a dose-dependent reduction in the number of SVs at synapses. Interestingly, the large SV clusters appeared to disperse into smaller SV clusters, as well as individual SVs. Thus, synuclein regulates clustering of SVs at resting synapses, as well as docking of SVs at the active zone. These findings reveal new roles for synuclein at the synapse and provide critical insights into diseases associated with α-synuclein dysfunction, such as Parkinson’s disease.
Collapse
Affiliation(s)
- Kaitlyn E Fouke
- The Eugene Bell Center for Regenerative Biology and Tissue Engineering, Marine Biological Laboratory, Woods Hole, MA, United States.,Department of Neurobiology, Duke University, Durham, NC, United States
| | - M Elizabeth Wegman
- The Eugene Bell Center for Regenerative Biology and Tissue Engineering, Marine Biological Laboratory, Woods Hole, MA, United States
| | - Sarah A Weber
- The Eugene Bell Center for Regenerative Biology and Tissue Engineering, Marine Biological Laboratory, Woods Hole, MA, United States.,Biological Sciences Collegiate Division, The University of Chicago, Chicago, IL, United States
| | - Emily B Brady
- The Eugene Bell Center for Regenerative Biology and Tissue Engineering, Marine Biological Laboratory, Woods Hole, MA, United States
| | - Cristina Román-Vendrell
- The Eugene Bell Center for Regenerative Biology and Tissue Engineering, Marine Biological Laboratory, Woods Hole, MA, United States
| | - Jennifer R Morgan
- The Eugene Bell Center for Regenerative Biology and Tissue Engineering, Marine Biological Laboratory, Woods Hole, MA, United States
| |
Collapse
|
43
|
Sawner AS, Ray S, Yadav P, Mukherjee S, Panigrahi R, Poudyal M, Patel K, Ghosh D, Kummerant E, Kumar A, Riek R, Maji SK. Modulating α-Synuclein Liquid-Liquid Phase Separation. Biochemistry 2021; 60:3676-3696. [PMID: 34431665 DOI: 10.1021/acs.biochem.1c00434] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Liquid-liquid phase separation (LLPS) is a crucial phenomenon for the formation of functional membraneless organelles. However, LLPS is also responsible for protein aggregation in various neurodegenerative diseases such as amyotrophic lateral sclerosis, Alzheimer's disease, and Parkinson's disease (PD). Recently, several reports, including ours, have shown that α-synuclein (α-Syn) undergoes LLPS and a subsequent liquid-to-solid phase transition, which leads to amyloid fibril formation. However, how the environmental (and experimental) parameters modulate the α-Syn LLPS remains elusive. Here, we show that in vitro α-Syn LLPS is strongly dependent on the presence of salts, which allows charge neutralization at both terminal segments of protein and therefore promotes hydrophobic interactions supportive for LLPS. Using various purification methods and experimental conditions, we showed, depending upon conditions, α-Syn undergoes either spontaneous (instantaneous) or delayed LLPS. Furthermore, we delineate that the kinetics of liquid droplet formation (i.e., the critical concentration and critical time) is relative and can be modulated by the salt/counterion concentration, pH, presence of surface, PD-associated multivalent cations, and N-terminal acetylation, which are all known to regulate α-Syn aggregation in vitro. Together, our observations suggest that α-Syn LLPS and subsequent liquid-to-solid phase transition could be pathological, which can be triggered only under disease-associated conditions (high critical concentration and/or conditions promoting α-Syn self-assembly). This study will significantly improve our understanding of the molecular mechanisms of α-Syn LLPS and the liquid-to-solid transition.
Collapse
Affiliation(s)
- Ajay Singh Sawner
- Department of Biosciences and Bioengineering, IIT Bombay, Powai, Mumbai 400076, India
| | - Soumik Ray
- Department of Biosciences and Bioengineering, IIT Bombay, Powai, Mumbai 400076, India
| | - Preeti Yadav
- Department of Biosciences and Bioengineering, IIT Bombay, Powai, Mumbai 400076, India
| | - Semanti Mukherjee
- Department of Biosciences and Bioengineering, IIT Bombay, Powai, Mumbai 400076, India
| | - Rajlaxmi Panigrahi
- Department of Biosciences and Bioengineering, IIT Bombay, Powai, Mumbai 400076, India
| | - Manisha Poudyal
- Department of Biosciences and Bioengineering, IIT Bombay, Powai, Mumbai 400076, India
| | - Komal Patel
- Department of Biosciences and Bioengineering, IIT Bombay, Powai, Mumbai 400076, India
| | - Dhiman Ghosh
- Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 1-5/10, 8093 Zürich, Switzerland
| | - Eric Kummerant
- Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 1-5/10, 8093 Zürich, Switzerland
| | - Ashutosh Kumar
- Department of Biosciences and Bioengineering, IIT Bombay, Powai, Mumbai 400076, India
| | - Roland Riek
- Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 1-5/10, 8093 Zürich, Switzerland
| | - Samir K Maji
- Department of Biosciences and Bioengineering, IIT Bombay, Powai, Mumbai 400076, India
| |
Collapse
|
44
|
Gadhe L, Sakunthala A, Mukherjee S, Gahlot N, Bera R, Sawner AS, Kadu P, Maji SK. Intermediates of α-synuclein aggregation: Implications in Parkinson's disease pathogenesis. Biophys Chem 2021; 281:106736. [PMID: 34923391 DOI: 10.1016/j.bpc.2021.106736] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 11/27/2021] [Accepted: 11/27/2021] [Indexed: 12/11/2022]
Abstract
Cytoplasmic deposition of aberrantly misfolded α-synuclein (α-Syn) is a common feature of synucleinopathies, including Parkinson's disease (PD). However, the precise pathogenic mechanism of α-Syn in synucleinopathies remains elusive. Emerging evidence has suggested that α-Syn may contribute to PD pathogenesis in several ways; wherein the contribution of fibrillar species, for exerting toxicity and disease transmission, cannot be neglected. Further, the oligomeric species could be the most plausible neurotoxic species causing neuronal cell death. However, understanding the structural and molecular insights of these oligomers are very challenging due to the heterogeneity and transient nature of the species. In this review, we discuss the recent advancements in understanding the formation and role of α-Syn oligomers in PD pathogenesis. We also summarize the different types of α-Syn oligomeric species and potential mechanisms to exert neurotoxicity. Finally, we address the possible ways to target α-Syn as a promising approach against PD and the possible future directions.
Collapse
Affiliation(s)
- Laxmikant Gadhe
- Department of Biosciences and Bioengineering, IIT Bombay, Powai, Mumbai 400076, India
| | - Arunima Sakunthala
- Department of Biosciences and Bioengineering, IIT Bombay, Powai, Mumbai 400076, India
| | - Semanti Mukherjee
- Department of Biosciences and Bioengineering, IIT Bombay, Powai, Mumbai 400076, India
| | - Nitisha Gahlot
- Department of Biosciences and Bioengineering, IIT Bombay, Powai, Mumbai 400076, India
| | - Riya Bera
- Department of Biosciences and Bioengineering, IIT Bombay, Powai, Mumbai 400076, India
| | - Ajay Singh Sawner
- Department of Biosciences and Bioengineering, IIT Bombay, Powai, Mumbai 400076, India
| | - Pradeep Kadu
- Department of Biosciences and Bioengineering, IIT Bombay, Powai, Mumbai 400076, India
| | - Samir K Maji
- Department of Biosciences and Bioengineering, IIT Bombay, Powai, Mumbai 400076, India.
| |
Collapse
|
45
|
Manganese promotes α-synuclein amyloid aggregation through the induction of protein phase transition. J Biol Chem 2021; 298:101469. [PMID: 34871547 PMCID: PMC8717548 DOI: 10.1016/j.jbc.2021.101469] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 11/24/2021] [Accepted: 11/25/2021] [Indexed: 01/31/2023] Open
Abstract
α-Synuclein (α-Syn) is the major protein component of Lewy bodies, a key pathological feature of Parkinson’s disease (PD). The manganese ion Mn2+ has been identified as an environmental risk factor of PD. However, it remains unclear how Mn2+ regulates α-Syn aggregation. Here, we discovered that Mn2+accelerates α-Syn amyloid aggregation through the regulation of protein phase separation. We found that Mn2+ not only promotes α-Syn liquid-to-solid phase transition but also directly induces soluble α-Syn monomers to form solid-like condensates. Interestingly, the lipid membrane is integrated into condensates during Mn2+-induced α-Syn phase transition; however, the preformed Mn2+/α-syn condensates can only recruit lipids to the surface of condensates. In addition, this phase transition can largely facilitate α-Syn amyloid aggregation. Although the Mn2+-induced condensates do not fuse, our results demonstrated that they could recruit soluble α-Syn monomers into the existing condensates. Furthermore, we observed that a manganese chelator reverses Mn2+-induced α-Syn aggregation during the phase transition stage. However, after maturation, α-Syn aggregation becomes irreversible. These findings demonstrate that Mn2+ facilitates α-Syn phase transition to accelerate the formation of α-Syn aggregates and provide new insights for targeting α-Syn phase separation in PD treatment.
Collapse
|
46
|
Trnka F, Hoffmann C, Wang H, Sansevrino R, Rankovic B, Rost BR, Schmitz D, Schmidt HB, Milovanovic D. Aberrant Phase Separation of FUS Leads to Lysosome Sequestering and Acidification. Front Cell Dev Biol 2021; 9:716919. [PMID: 34746121 PMCID: PMC8569517 DOI: 10.3389/fcell.2021.716919] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Accepted: 09/17/2021] [Indexed: 12/20/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease that leads to the death of upper and lower motor neurons. While most cases of ALS are sporadic, some of the familial forms of the disease are caused by mutations in the gene encoding for the RNA-binding protein FUS. Under physiological conditions, FUS readily phase separates into liquid-like droplets in vivo and in vitro. ALS-associated mutations interfere with this process and often result in solid-like aggregates rather than fluid condensates. Yet, whether cells recognize and triage aberrant condensates remains poorly understood, posing a major barrier to the development of novel ALS treatments. Using a combination of ALS-associated FUS mutations, optogenetic manipulation of FUS condensation, chemically induced stress, and pH-sensitive reporters of organelle acidity, we systematically characterized the cause-effect relationship between the material state of FUS condensates and the sequestering of lysosomes. From our data, we can derive three conclusions. First, regardless of whether we use wild-type or mutant FUS, expression levels (i.e., high concentrations) play a dominant role in determining the fraction of cells having soluble or aggregated FUS. Second, chemically induced FUS aggregates recruit LAMP1-positive structures. Third, mature, acidic lysosomes accumulate only at FUS aggregates but not at liquid-condensates. Together, our data suggest that lysosome-degradation machinery actively distinguishes between fluid and solid condensates. Unraveling these aberrant interactions and testing strategies to manipulate the autophagosome-lysosome axis provides valuable clues for disease intervention.
Collapse
Affiliation(s)
- Franziska Trnka
- Laboratory of Molecular Neuroscience, German Center for Neurodegenerative Diseases (DZNE), Berlin, Germany
| | - Christian Hoffmann
- Laboratory of Molecular Neuroscience, German Center for Neurodegenerative Diseases (DZNE), Berlin, Germany
| | - Han Wang
- Laboratory of Molecular Neuroscience, German Center for Neurodegenerative Diseases (DZNE), Berlin, Germany
| | - Roberto Sansevrino
- Laboratory of Molecular Neuroscience, German Center for Neurodegenerative Diseases (DZNE), Berlin, Germany
| | - Branislava Rankovic
- Laboratory of Molecular Neuroscience, German Center for Neurodegenerative Diseases (DZNE), Berlin, Germany
| | - Benjamin R Rost
- Laboratory of Network Dysfunction, German Center for Neurodegenerative Diseases (DZNE), Berlin, Germany
| | - Dietmar Schmitz
- Laboratory of Network Dysfunction, German Center for Neurodegenerative Diseases (DZNE), Berlin, Germany.,Berlin Institute of Health, NeuroCure Cluster of Excellence, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - H Broder Schmidt
- Department of Biochemistry, Stanford School of Medicine, Stanford, CA, United States
| | - Dragomir Milovanovic
- Laboratory of Molecular Neuroscience, German Center for Neurodegenerative Diseases (DZNE), Berlin, Germany
| |
Collapse
|
47
|
Specht CG. A Quantitative Perspective of Alpha-Synuclein Dynamics - Why Numbers Matter. Front Synaptic Neurosci 2021; 13:753462. [PMID: 34744680 PMCID: PMC8569944 DOI: 10.3389/fnsyn.2021.753462] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Accepted: 09/30/2021] [Indexed: 12/02/2022] Open
Abstract
The function of synapses depends on spatially and temporally controlled molecular interactions between synaptic components that can be described in terms of copy numbers, binding affinities, and diffusion properties. To understand the functional role of a given synaptic protein, it is therefore crucial to quantitatively characterise its biophysical behaviour in its native cellular environment. Single molecule localisation microscopy (SMLM) is ideally suited to obtain quantitative information about synaptic proteins on the nanometre scale. Molecule counting of recombinant proteins tagged with genetically encoded fluorophores offers a means to determine their absolute copy numbers at synapses due to the known stoichiometry of the labelling. As a consequence of its high spatial precision, SMLM also yields accurate quantitative measurements of molecule concentrations. In addition, live imaging of fluorescently tagged proteins at synapses can reveal diffusion dynamics and local binding properties of behaving proteins under normal conditions or during pathological processes. In this perspective, it is argued that the detailed structural information provided by super-resolution imaging can be harnessed to gain new quantitative information about the organisation and dynamics of synaptic components in cellula. To illustrate this point, I discuss the concentration-dependent aggregation of α-synuclein in the axon and the concomitant changes in the dynamic equilibrium of α-synuclein at synapses in quantitative terms.
Collapse
Affiliation(s)
- Christian G. Specht
- Diseases and Hormones of the Nervous System (DHNS), Inserm, Université Paris-Saclay, Paris, France
| |
Collapse
|
48
|
Sarchione A, Marchand A, Taymans JM, Chartier-Harlin MC. Alpha-Synuclein and Lipids: The Elephant in the Room? Cells 2021; 10:2452. [PMID: 34572099 PMCID: PMC8467310 DOI: 10.3390/cells10092452] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 09/10/2021] [Accepted: 09/12/2021] [Indexed: 12/17/2022] Open
Abstract
Since the initial identification of alpha-synuclein (α-syn) at the synapse, numerous studies demonstrated that α-syn is a key player in the etiology of Parkinson's disease (PD) and other synucleinopathies. Recent advances underline interactions between α-syn and lipids that also participate in α-syn misfolding and aggregation. In addition, increasing evidence demonstrates that α-syn plays a major role in different steps of synaptic exocytosis. Thus, we reviewed literature showing (1) the interplay among α-syn, lipids, and lipid membranes; (2) advances of α-syn synaptic functions in exocytosis. These data underscore a fundamental role of α-syn/lipid interplay that also contributes to synaptic defects in PD. The importance of lipids in PD is further highlighted by data showing the impact of α-syn on lipid metabolism, modulation of α-syn levels by lipids, as well as the identification of genetic determinants involved in lipid homeostasis associated with α-syn pathologies. While questions still remain, these recent developments open the way to new therapeutic strategies for PD and related disorders including some based on modulating synaptic functions.
Collapse
Affiliation(s)
| | | | | | - Marie-Christine Chartier-Harlin
- Univ. Lille, Inserm, CHU Lille, UMR-S 1172—LilNCog—Lille Neuroscience and Cognition, F-59000 Lille, France; (A.S.); (A.M.); (J.-M.T.)
| |
Collapse
|
49
|
Wang H, Kelley FM, Milovanovic D, Schuster BS, Shi Z. Surface tension and viscosity of protein condensates quantified by micropipette aspiration. BIOPHYSICAL REPORTS 2021; 1:100011. [PMID: 36247368 PMCID: PMC9563586 DOI: 10.1016/j.bpr.2021.100011] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Accepted: 07/26/2021] [Indexed: 12/14/2022]
Abstract
The material properties of biomolecular condensates have been suggested to play important biological and pathological roles. Despite the rapid increase in the number of biomolecules identified that undergo liquid-liquid phase separation, quantitative studies and direct measurements of the material properties of the resulting condensates have been severely lagging behind. Here, we develop a micropipette-based technique that uniquely, to our knowledge, allows quantifications of both the surface tension and viscosity of biomolecular condensates, independent of labeling and surface-wetting effects. We demonstrate the accuracy and versatility of this technique by measuring condensates of LAF-1 RGG domains and a polymer-based aqueous two-phase system. We further confirm our measurements using established condensate fusion and fluorescence recovery after photobleaching assays. We anticipate the micropipette-based technique will be widely applicable to biomolecular condensates and will resolve several limitations regarding current approaches.
Collapse
Affiliation(s)
- Huan Wang
- Department of Chemistry and Chemical Biology
| | - Fleurie M. Kelley
- Department of Chemical and Biochemical Engineering, Rutgers University, Piscataway, New Jersey
| | - Dragomir Milovanovic
- Laboratory of Molecular Neuroscience, German Center for Neurodegenerative Diseases, Berlin, Germany
| | - Benjamin S. Schuster
- Department of Chemical and Biochemical Engineering, Rutgers University, Piscataway, New Jersey
| | - Zheng Shi
- Department of Chemistry and Chemical Biology
| |
Collapse
|
50
|
Elbaum-Garfinkle S, Kriwacki RW. Phase Separation in Biology & Disease: The next chapter. J Mol Biol 2021; 433:166990. [PMID: 33857471 DOI: 10.1016/j.jmb.2021.166990] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Shana Elbaum-Garfinkle
- Structural Biology Initiative, CUNY Advanced Science Research Center, Biochemistry, The Graduate Center CUNY, 85 St. Nicholas Terrace, New York, NY 10031, United States.
| | - Richard W Kriwacki
- Department of Structural Biology, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105-3678, United States.
| |
Collapse
|