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Wang HY, Dey S, Levental KR. Applications of phase-separating multi-bilayers in protein-membrane domain interactions. Methods Enzymol 2024; 700:275-294. [PMID: 38971603 DOI: 10.1016/bs.mie.2024.04.024] [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] [Indexed: 07/08/2024]
Abstract
Synthetic model membranes are important tools to elucidate lipid domain and protein interactions due to predefined lipid compositions and characterizable biophysical properties. Here, we introduce a model membrane with multiple lipid bilayers (multi-bilayers) stacked on a mica substrate that is prepared through a spin-coating technique. The spin-coated multi-bilayers are useful in the study of phase separated membranes with a high cholesterol content, mobile lipids, microscopic and reversible phase separation, and easy conjugation with proteins, which make them a good model to study interactions between proteins and membrane domains.
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Affiliation(s)
- Hong-Yin Wang
- Department of Molecular Physiology and Biological Physics, Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, VA, United States
| | - Simli Dey
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR168, Physics of Cells and Cancer, Paris, France
| | - Kandice R Levental
- Department of Molecular Physiology and Biological Physics, Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, VA, United States.
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2
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Sutherland M, Kwon B, Hong M. Interactions of HIV gp41's membrane-proximal external region and transmembrane domain with phospholipid membranes from 31P NMR. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2021; 1863:183723. [PMID: 34352242 DOI: 10.1016/j.bbamem.2021.183723] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 07/22/2021] [Accepted: 07/30/2021] [Indexed: 11/30/2022]
Abstract
HIV-1 entry into cells requires coordinated changes of the conformation and dynamics of both the fusion protein, gp41, and the lipids in the cell membrane and virus envelope. Commonly proposed features of membrane deformation during fusion include high membrane curvature, lipid disorder, and membrane surface dehydration. The virus envelope and target cell membrane contain a diverse set of phospholipids and cholesterol. To dissect how different lipids interact with gp41 to contribute to membrane fusion, here we use 31P solid-state NMR spectroscopy to investigate the curvature, dynamics, and hydration of POPE, POPC and POPS membranes, with and without cholesterol, in the presence of a peptide comprising the membrane proximal external region (MPER) and transmembrane domain (TMD) of gp41. Static 31P NMR spectra indicate that the MPER-TMD induces strong negative Gaussian curvature (NGC) to the POPE membrane but little curvature to POPC and POPC:POPS membranes. The NGC manifests as an isotropic peak in the static NMR spectra, whose intensity increases with the peptide concentration. Cholesterol inhibits the NGC formation and stabilizes the lamellar phase. Relative intensities of magic-angle spinning 31P cross-polarization and direct-polarization spectra indicate that all three phospholipids become more mobile upon peptide binding. Finally, 2D 1H-31P correlation spectra show that the MPER-TMD enhances water 1H polarization transfer to the lipids, indicating that the membrane surfaces become more hydrated. These results suggest that POPE is an essential component of the high-curvature fusion site, and lipid dynamic disorder is a general feature of membrane restructuring during fusion.
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Affiliation(s)
- Madeleine Sutherland
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Byungsu Kwon
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Mei Hong
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA.
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3
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Liquid-like protein interactions catalyse assembly of endocytic vesicles. Nat Cell Biol 2021; 23:366-376. [PMID: 33820972 PMCID: PMC8035231 DOI: 10.1038/s41556-021-00646-5] [Citation(s) in RCA: 90] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 02/08/2021] [Indexed: 12/11/2022]
Abstract
During clathrin-mediated endocytosis, dozens of proteins assemble into an interconnected network at the plasma membrane. As initiators of endocytosis, Eps15 and Fcho1/2 concentrate downstream components, while permitting dynamic rearrangement within the budding vesicle. How do initiator proteins meet these competing demands? Here we show that Eps15 and Fcho1/2 rely on weak, liquid-like interactions to catalyze endocytosis. In vitro, these weak interactions promote the assembly of protein droplets with liquid-like properties. To probe the physiological role of these liquid-like networks, we tuned the strength of initiator protein assembly in real time using light-inducible oligomerization of Eps15. Low light levels drove liquid-like assemblies, restoring normal rates of endocytosis in mammalian Eps15 knockout cells. In contrast, initiator proteins formed solid-like assemblies upon exposure to higher light levels, which stalled vesicle budding, likely owing to insufficient molecular rearrangement. These findings suggest that liquid-like assembly of initiator proteins provides an optimal catalytic platform for endocytosis.
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Canepa E, Salassi S, de Marco AL, Lambruschini C, Odino D, Bochicchio D, Canepa F, Canale C, Dante S, Brescia R, Stellacci F, Rossi G, Relini A. Amphiphilic gold nanoparticles perturb phase separation in multidomain lipid membranes. NANOSCALE 2020; 12:19746-19759. [PMID: 32966489 DOI: 10.1039/d0nr05366j] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Amphiphilic gold nanoparticles with diameters in the 2-4 nm range are promising as theranostic agents thanks to their spontaneous translocation through cell membranes. This study addresses the effects that these nanoparticles may have on a distinct feature of plasma membranes: lipid lateral phase separation. Atomic force microscopy, quartz crystal microbalance, and molecular dynamics are combined to study the interaction between model neuronal membranes, which spontaneously form ordered and disordered lipid domains, and amphiphilic gold nanoparticles having negatively charged surface functionalization. Nanoparticles are found to interact with the bilayer and form bilayer-embedded ordered aggregates. Nanoparticles also suppress lipid phase separation, in a concentration-dependent fashion. A general, yet simple thermodynamic model is developed to show that the change of lipid-lipid enthalpy is the dominant driving force towards the nanoparticle-induced destabilization of phase separation.
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Affiliation(s)
- Ester Canepa
- Department of Chemistry and Industrial Chemistry, University of Genoa, Via Dodecaneso 31, 16146 Genoa, Italy.
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Soloviov D, Cai YQ, Bolmatov D, Suvorov A, Zhernenkov K, Zav'yalov D, Bosak A, Uchiyama H, Zhernenkov M. Functional lipid pairs as building blocks of phase-separated membranes. Proc Natl Acad Sci U S A 2020; 117:4749-4757. [PMID: 32071249 PMCID: PMC7060688 DOI: 10.1073/pnas.1919264117] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Biological membranes exhibit a great deal of compositional and phase heterogeneity due to hundreds of chemically distinct components. As a result, phase separation processes in cell membranes are extremely difficult to study, especially at the molecular level. It is currently believed that the lateral membrane heterogeneity and the formation of domains, or rafts, are driven by lipid-lipid and lipid-protein interactions. Nevertheless, the underlying mechanisms regulating membrane heterogeneity remain poorly understood. In the present work, we combine inelastic X-ray scattering with molecular dynamics simulations to provide direct evidence for the existence of strongly coupled transient lipid pairs. These lipid pairs manifest themselves experimentally through optical vibrational (a.k.a. phononic) modes observed in binary (1,2-dipalmitoyl-sn-glycero-3-phosphocholine [DPPC]-cholesterol) and ternary (DPPC-1,2-dioleoyl-sn-glycero-3-phosphocholine/1-palmitoyl-2-oleoyl-glycero-3-phosphocholine [DOPC/POPC]-cholesterol) systems. The existence of a phononic gap in these vibrational modes is a direct result of the finite size of patches formed by these lipid pairs. The observation of lipid pairs provides a spatial (subnanometer) and temporal (subnanosecond) window into the lipid-lipid interactions in complex mixtures of saturated/unsaturated lipids and cholesterol. Our findings represent a step toward understanding the lateral organization and dynamics of membrane domains using a well-validated probe with a high spatial and temporal resolution.
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Affiliation(s)
- Dmytro Soloviov
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny 141701, Russia
- Frank Laboratory for Neutron Physics, Joint Institute for Nuclear Research, Dubna 141980, Russia
- Department of Physics, Taras Shevchenko National University of Kyiv, Kyiv 01601, Ukraine
- Nuclear Facility Safety Department, Institute for Safety Problems of Nuclear Power Plants of National Academy of Science of Ukraine, Chornobyl 07270, Ukraine
| | - Yong Q Cai
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY 11973
| | - Dima Bolmatov
- Large Scale Structures Group, Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831
- Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996
| | - Alexey Suvorov
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY 11973
| | - Kirill Zhernenkov
- Jülich Centre for Neutron Science at Heinz Maier-Leibnitz Zentrum, Forschungszentrum Jülich GmbH, 85748 Garching, Germany
- Frank Laboratory for Neutron Physics, Joint Institute for Nuclear Research, Dubna 141980, Russia
| | - Dmitry Zav'yalov
- Department of Physics, Volgograd State Technical University, Volgograd 400005, Russia
| | - Alexey Bosak
- Experiments Division, European Synchrotron Radiation Facility, 38043 Grenoble, France
| | - Hiroshi Uchiyama
- Japan Synchrotron Radiation Research Institute, SPring-8, Sayo, Hyogo 679-5198, Japan
| | - Mikhail Zhernenkov
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY 11973;
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Dang AT, He W, Ivey DB, Coleman MA, Kuhl TL. Lipid and Protein Transfer between Nanolipoprotein Particles and Supported Lipid Bilayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:12071-12078. [PMID: 31442053 PMCID: PMC7024587 DOI: 10.1021/acs.langmuir.9b01288] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
A nanolipoprotein particle (NLP) is a lipid bilayer disc stabilized by two amphipathic "scaffold" apolipoproteins. It has been most notably utilized as a tool for solubilizing a variety of membrane proteins while preserving structural and functional properties. Transfer of functional proteins from NLPs into model membrane systems such as supported lipid bilayers (SLBs) would enable new opportunities, for example, two-dimensional protein crystallization and studies on protein-protein interactions. This work used fluorescence microscopy and atomic force microscopy to investigate the interaction between NLPs and SLBs. When incubated with SLBs, NLPs were found to spontaneously deliver lipid and protein cargo. The impact of membrane composition on lipid exchange was explored, revealing a positive correlation between the magnitude of lipid transfer and concentration of defects in the target SLB. Incorporation of lipids capable of binding specifically to polyhistidine tags encoded into the apolipoproteins also boosted transfer of NLP cargo. Optimal conditions for lipid and protein delivery from NLPs to SLBs are proposed based on interaction mechanisms.
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Affiliation(s)
- Amanda T. Dang
- Department of Materials Science and Engineering, University of California, Davis CA 95616
| | - Wei He
- Lawrence Livermore National Laboratory, Livermore, CA 94550
| | - Daniela B. Ivey
- Department of Chemical Engineering, University of California, Davis CA 95616
| | | | - Tonya L. Kuhl
- Department of Chemical Engineering, University of California, Davis CA 95616
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Snead WT, Stachowiak JC. Structure Versus Stochasticity-The Role of Molecular Crowding and Intrinsic Disorder in Membrane Fission. J Mol Biol 2018; 430:2293-2308. [PMID: 29627460 DOI: 10.1016/j.jmb.2018.03.024] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 03/22/2018] [Accepted: 03/26/2018] [Indexed: 01/07/2023]
Abstract
Cellular membranes must undergo remodeling to facilitate critical functions including membrane trafficking, organelle biogenesis, and cell division. An essential step in membrane remodeling is membrane fission, in which an initially continuous membrane surface is divided into multiple, separate compartments. The established view has been that membrane fission requires proteins with conserved structural features such as helical scaffolds, hydrophobic insertions, and polymerized assemblies. In this review, we discuss these structure-based fission mechanisms and highlight recent findings from several groups that support an alternative, structure-independent mechanism of membrane fission. This mechanism relies on lateral collisions among crowded, membrane-bound proteins to generate sufficient steric pressure to drive membrane vesiculation. As a stochastic process, this mechanism contrasts with the paradigm that deterministic protein structures are required to drive fission, raising the prospect that many more proteins may participate in fission than previously thought. Paradoxically, our recent work suggests that intrinsically disordered domains may be among the most potent drivers of membrane fission, owing to their large hydrodynamic radii and substantial chain entropy. This stochastic view of fission also suggests new roles for the structure-based fission proteins. Specifically, we hypothesize that in addition to driving fission directly, the canonical fission machines may facilitate the enrichment and organization of bulky disordered protein domains in order to promote membrane fission by locally amplifying protein crowding.
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Affiliation(s)
- Wilton T Snead
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712, USA
| | - Jeanne C Stachowiak
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712, USA; Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX 78712, USA.
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8
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Zeno WF, Ogunyankin MO, Longo ML. Scaling relationships for translational diffusion constants applied to membrane domain dissolution and growth. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:1994-2003. [PMID: 29501605 DOI: 10.1016/j.bbamem.2018.02.028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Revised: 02/24/2018] [Accepted: 02/26/2018] [Indexed: 01/10/2023]
Abstract
We compare the way that relationships for diffusion constants scale with the size of diffusing membrane domains and the geometry of their environments. Then, we review our experimental work on the dynamics of dissolution/growth of membrane domains in crowding induced mixing, phase separation, and Ostwald ripening in a highly confined environment. Overall, the scaling relationships applied to diffusion constants obtained by fits to our dynamic data indicate that dissolution and growth is influenced by the diffusion of clusters or small domains of lipids, in addition to kinetic processes and geometrical constraints.
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Affiliation(s)
- Wade F Zeno
- Department of Chemical Engineering, University of California Davis, Davis, CA 95616, United States
| | - Maria O Ogunyankin
- Department of Chemical Engineering, University of California Davis, Davis, CA 95616, United States
| | - Marjorie L Longo
- Department of Chemical Engineering, University of California Davis, Davis, CA 95616, United States.
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Xia Y, Jang HS, Shen Z, Bothun GD, Li Y, Nieh MP. Effects of Membrane Defects and Polymer Hydrophobicity on Networking Kinetics of Vesicles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:5745-5751. [PMID: 28510460 DOI: 10.1021/acs.langmuir.7b00373] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The kinetics of clustering unilamellar vesicles induced by inverse Pluronics [poly(propylene oxide)m-poly(ethylene oxide)n-poly(propylene oxide)m, POm-EOn-POm] was investigated via experiments and molecular dynamic simulations. Two important factors for controlling the networking kinetics are the membrane defects, presumably located at the interfacial region between two lipid domains induced by acyl chain mismatch, and the polymer hydrophobicity. As expected, the clustering rate increases significantly with increasing bilayer defects on the membrane where the insertion of PPO is likely to take place because of the reduced energy barrier for the insertion of PO. The hydrophobic interaction between the PO blocks and membranes with the defects region dictates the "anchoring" kinetics, which is controlled by the association-dissociation of PO with the lipid membrane. As a result, the dependence of clustering rate on polymer concentration is strongly influenced by the hydrophobicity of the PO blocks. Nevertheless, longer PO blocks show stronger association with the membrane, resulting in faster consumption of the "active" sites made of these defect regions (causing mostly "invalid" insertions) with increasing polymer concentration, hence inhibiting the formation of large networking clusters, while shorter PO blocks undergo more frequent association with/dissociation from the defects, allowing continuous formation of larger clusters with increasing polymer concentration. This study provides important insights into how the organization and dynamics of a biomembrane influence its interaction with foreign amphiphilic molecules.
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Affiliation(s)
| | - Hyun-Sook Jang
- Center for Soft and Living Matter (CSLM), Institute for Basic Science (IBS) , Ulju-gun, Ulsan 689-798, Republic of Korea
| | | | - Geoffrey D Bothun
- Department of Chemical Engineering, University of Rhode Island , Kingston, Rhode Island 02881, United States
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Zeno WF, Johnson KE, Sasaki DY, Risbud SH, Longo ML. Dynamics of Crowding-Induced Mixing in Phase Separated Lipid Bilayers. J Phys Chem B 2016; 120:11180-11190. [PMID: 27723342 PMCID: PMC5548394 DOI: 10.1021/acs.jpcb.6b07119] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
We use fluorescence microscopy to examine the dynamics of the crowding-induced mixing transition of liquid ordered (Lo)-liquid disordered (Ld) phase separated lipid bilayers when the following particles of increasing size bind to either the Lo or Ld phase: Ubiquitin, green fluorescent protein (GFP), and nanolipoprotein particles (NLPs) of two diameters. These proteinaceous particles contained histidine-tags, which were phase targeted by binding to iminodiacetic acid (IDA) head groups, via a Cu2+ chelating mechanism, of lipids that specifically partition into either the Lo phase or Ld phase. The degree of steric pressure was controlled by varying the size of the bound particle (10-240 kDa) and the amount of binding sites present (i.e., DPIDA concentrations of 9 and 12 mol%) in the supported lipid multibilayer platform used here. We develop a mass transfer-based diffusional model to analyze the observed Lo phase domain dissolution that, along with visual observations and activation energy calculations, provides insight into the sequence of events in crowding-induced mixing. Our results suggest that the degree of steric pressure and target phase influence not only the efficacy of steric-pressure induced mixing, but the rate and controlling mechanism for which it occurs.
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Affiliation(s)
- Wade F. Zeno
- Department of Chemical Engineering, University of California Davis, Davis, California 95616, United States
| | - Kaitlin E. Johnson
- Department of Chemical Engineering, University of California Davis, Davis, California 95616, United States
| | - Darryl Y. Sasaki
- Sandia National Laboratories, P.O. Box 969, Livermore, California 94551, United States
| | - Subhash H. Risbud
- Department of Materials Science and Engineering, University of California Davis, Davis, California 95616, United States
| | - Marjorie L. Longo
- Department of Chemical Engineering, University of California Davis, Davis, California 95616, United States
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