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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.
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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
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Shillcock JC, Brochut M, Chénais E, Ipsen JH. Phase behaviour and structure of a model biomolecular condensate. SOFT MATTER 2020; 16:6413-6423. [PMID: 32584357 DOI: 10.1039/d0sm00813c] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Phase separation of immiscible fluids is a common phenomenon in polymer chemistry, and is recognized as an important mechanism by which cells compartmentalize their biochemical reactions. Biomolecular condensates are condensed fluid droplets in cells that form by liquid-liquid phase separation of intrinsically-disordered proteins. They have a wide range of functions and are associated with chronic neurodegenerative diseases in which they become pathologically rigid. However, it remains unclear how their material properties depend on the molecular structure of the proteins. Here we explore the phase behaviour and structure of a model biomolecular condensate composed of semi-flexible polymers with attractive end-caps using coarse-grained simulations. The model contains the minimal molecular features that are sufficient to observe liquid-liquid phase separation of soluble polymers into a porous, three-dimensional network in which their end-caps reversibly bind at junctions. The distance between connected junctions scales with the polymer length as a self-avoiding random walk over a wide range of concentration with a weak affinity-dependent prefactor. By contrast, the average number of polymers that meet at the junctions depends on the end-cap affinity but only weakly on the polymer length. The structured porosity of the condensed phase suggests a mechanism for cells to regulate biomolecular condensates. Protein interaction sites may be turned on or off to modulate the condensate's porosity and therefore the diffusion and interaction of additional proteins.
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Affiliation(s)
- J C Shillcock
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.
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Das T, Eliezer D. Membrane interactions of intrinsically disordered proteins: The example of alpha-synuclein. BIOCHIMICA ET BIOPHYSICA ACTA. PROTEINS AND PROTEOMICS 2019; 1867:879-889. [PMID: 31096049 PMCID: PMC6661188 DOI: 10.1016/j.bbapap.2019.05.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Revised: 05/03/2019] [Accepted: 05/08/2019] [Indexed: 12/11/2022]
Abstract
Peripheral membrane proteins associate reversibly with biological membranes that, compared to protein binding partners, are structurally labile and devoid of specific binding pockets. Membranes in different subcellular compartments vary primarily in their chemical composition and physical properties, and recognition of these features is therefore critical for allowing such proteins to engage their proper membrane targets. Intrinsically disordered proteins (IDPs) are well-suited to accomplish this task using highly specific and low- to moderate-affinity interactions governed by recognition principles that are both similar to and different from those that mediate the membrane interactions of rigid proteins. IDPs have also evolved multiple mechanisms to regulate membrane (and other) interactions and achieve their impressive functional diversity. Moreover, IDP-membrane interactions may have a kinetic advantage in fast processes requiring rapid control of such interactions, such as synaptic transmission or signaling. Herein we review the biophysics, regulation and functional implications of IDP-membrane interactions and include a brief overview of some of the methods that can be used to study such interactions. At each step, we use the example of alpha-synuclein, a protein involved in the pathogenesis of Parkinson's disease and one of the best characterized membrane-binding IDP, to illustrate some of the principles discussed.
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Affiliation(s)
- Tapojyoti Das
- Department of Biochemistry, Weill Cornell Medicine, New York, NY, United States of America
| | - David Eliezer
- Department of Biochemistry, Weill Cornell Medicine, New York, NY, United States of America.
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Truong TV, Ghosh M, Hosamani B, Baiju TV, Dhandapani G, Wachtel E, Kesselman E, Danino D, Sheves M, Namboothiri IN, Patchornik G. Controlled micelle conjugation via charged peptide amphiphiles. J Pept Sci 2019; 25:e3174. [DOI: 10.1002/psc.3174] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Revised: 04/04/2019] [Accepted: 04/10/2019] [Indexed: 12/19/2022]
Affiliation(s)
| | - Mihir Ghosh
- Faculty of ChemistryWeizmann Institute of Science Rehovot Israel
| | | | - Thekke V. Baiju
- Department of ChemistryIndian Institute of Technology Bombay Mumbai India
| | | | - Ellen Wachtel
- Department of ChemistryIndian Institute of Technology Bombay Mumbai India
| | - Ellina Kesselman
- Department of Biotechnology and Food EngineeringTechnion Haifa Israel
| | - Dganit Danino
- Department of Biotechnology and Food EngineeringTechnion Haifa Israel
| | - Mordechai Sheves
- Faculty of ChemistryWeizmann Institute of Science Rehovot Israel
| | | | - Guy Patchornik
- Department of Chemical SciencesAriel University Ariel Israel
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