1
|
Johnson DH, Kou OH, Bouzos N, Zeno WF. Protein-membrane interactions: sensing and generating curvature. Trends Biochem Sci 2024; 49:401-416. [PMID: 38508884 PMCID: PMC11069444 DOI: 10.1016/j.tibs.2024.02.005] [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: 09/23/2023] [Revised: 02/20/2024] [Accepted: 02/23/2024] [Indexed: 03/22/2024]
Abstract
Biological membranes are integral cellular structures that can be curved into various geometries. These curved structures are abundant in cells as they are essential for various physiological processes. However, curved membranes are inherently unstable, especially on nanometer length scales. To stabilize curved membranes, cells can utilize proteins that sense and generate membrane curvature. In this review, we summarize recent research that has advanced our understanding of interactions between proteins and curved membrane surfaces, as well as work that has expanded our ability to study curvature sensing and generation. Additionally, we look at specific examples of cellular processes that require membrane curvature, such as neurotransmission, clathrin-mediated endocytosis (CME), and organelle biogenesis.
Collapse
Affiliation(s)
- David H Johnson
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA 90089, USA
| | - Orianna H Kou
- Department of Physics and Astronomy, University of Southern California, Los Angeles, CA 90089, USA
| | - Nicoletta Bouzos
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA 90089, USA
| | - Wade F Zeno
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA 90089, USA.
| |
Collapse
|
2
|
Nehls C, Schröder M, Haubenthal T, Haas A, Gutsmann T. The mechanistic basis of the membrane-permeabilizing activities of the virulence-associated protein A (VapA) from Rhodococcus equi. Mol Microbiol 2024; 121:578-592. [PMID: 38308564 DOI: 10.1111/mmi.15233] [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: 06/20/2023] [Revised: 01/12/2024] [Accepted: 01/17/2024] [Indexed: 02/05/2024]
Abstract
Pathogenic Rhodococcus equi release the virulence-associated protein A (VapA) within macrophage phagosomes. VapA permeabilizes phagosome and lysosome membranes and reduces acidification of both compartments. Using biophysical techniques, we found that VapA interacts with model membranes in four steps: (i) binding, change of mechanical properties, (ii) formation of specific membrane domains, (iii) permeabilization within the domains, and (iv) pH-specific transformation of domains. Biosensor data revealed that VapA binds to membranes in one step at pH 6.5 and in two steps at pH 4.5 and decreases membrane fluidity. The integration of VapA into lipid monolayers was only significant at lateral pressures <20 mN m-1 indicating preferential incorporation into membrane regions with reduced integrity. Atomic force microscopy of lipid mono- and bilayers showed that VapA increased the surface heterogeneity of liquid disordered domains. Furthermore, VapA led to the formation of a new microstructured domain type and, at pH 4.5, to the formation of 5 nm high domains. VapA binding, its integration and lipid domain formation depended on lipid composition, pH, protein concentration and lateral membrane pressure. VapA-mediated permeabilization is clearly distinct from that caused by classical microbial pore formers and is a key contribution to the multiplication of Rhodococcus equi in phagosomes.
Collapse
Affiliation(s)
- Christian Nehls
- Division of Biophysics, Research Center Borstel - Leibniz Lung Center, Borstel, Germany
- Centre for Structural Systems Biology (CSSB), Hamburg, Germany
- Kiel Nano, Surface and Interface Science KiNSIS, Kiel University, Kiel, Germany
| | - Marcel Schröder
- Division of Biophysics, Research Center Borstel - Leibniz Lung Center, Borstel, Germany
| | | | - Albert Haas
- Cell Biology Institute, University of Bonn, Bonn, Germany
| | - Thomas Gutsmann
- Division of Biophysics, Research Center Borstel - Leibniz Lung Center, Borstel, Germany
- Centre for Structural Systems Biology (CSSB), Hamburg, Germany
- Kiel Nano, Surface and Interface Science KiNSIS, Kiel University, Kiel, Germany
| |
Collapse
|
3
|
Campelo F, Tian M, von Blume J. Rediscovering the intricacies of secretory granule biogenesis. Curr Opin Cell Biol 2023; 85:102231. [PMID: 37657367 DOI: 10.1016/j.ceb.2023.102231] [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: 06/16/2023] [Revised: 08/01/2023] [Accepted: 08/07/2023] [Indexed: 09/03/2023]
Abstract
Regulated secretion, an essential cellular process, relies on secretory granules (SGs) for the controlled release of a diverse range of cargo molecules, including proteins, peptides, hormones, enzymes, and neurotransmitters. SG biogenesis encompasses cargo selection, sorting, packaging, and trafficking, with the trans-Golgi Network (TGN) playing a central role. Research in the last three decades has revealed significant components required for SG biogenesis; however, no cargo receptor transferring granule cargo from the TGN to immature SGs (ISGs) has yet been identified. Consequently, recent research has devoted significant attention to studying receptor-independent cargo sorting mechanisms, shedding new light on the complexities of regulated secretion. Understanding the underlying molecular and biophysical mechanisms behind cargo sorting into ISGs holds great promise for advancing our knowledge of cellular communication and disease mechanisms.
Collapse
Affiliation(s)
- Felix Campelo
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860, Castelldefels, Barcelona, Spain
| | - Meng Tian
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA
| | - Julia von Blume
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA.
| |
Collapse
|
4
|
Liu P, Beltramo PJ. Effects of crowding on the diffusivity of membrane adhered particles. SOFT MATTER 2023; 19:7708-7716. [PMID: 37791427 DOI: 10.1039/d3sm01269g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
The lateral diffusion of cell membrane inclusions, such as integral membrane proteins and bound receptors, drives critical biological processes, including the formation of complexes, cell-cell signaling, and membrane trafficking. These diffusive processes are complicated by how concentrated, or "crowded", the inclusions are, which can occupy between 30-50% of the area fraction of the membrane. In this work, we elucidate the effects of increasing concentration of model membrane inclusions in a free-standing artificial cell membrane on inclusion diffusivity and the apparent viscosity of the membrane. By multiple particle tracking of fluorescent microparticles covalently tethered to the bilayer, we show the transition from expected Brownian dynamics, which accurately measure the membrane viscosity, to subdiffusive behavior with decreased diffusion coefficient as the particle area fraction increases from 1% to around 30%, approaching physiological levels of crowding. At high crowding, the onset of non-Gaussian behavior is observed. Using hydrodynamic models relating the 2D diffusion coefficient to the viscosity of a membrane, we determine the apparent viscosity of the bilayer from the particle diffusivity and show an increase in the apparent membrane viscosity with increasing particle area fraction. However, the scaling of this increase is in contrast with the behavior of monolayer inclusion diffusion and bulk suspension rheology. These results demonstrate that physiological levels of model membrane crowding nontrivially alter the dynamics and apparent viscosity of the system, which has implications for understanding membrane protein interactions and particle-membrane transport processes.
Collapse
Affiliation(s)
- Paige Liu
- Department of Chemical Engineering, University of Massachusetts Amherst, Amherst, MA 01003, USA.
| | - Peter J Beltramo
- Department of Chemical Engineering, University of Massachusetts Amherst, Amherst, MA 01003, USA.
| |
Collapse
|
5
|
Yuan F, Lee CT, Sangani A, Houser JR, Wang L, Lafer EM, Rangamani P, Stachowiak JC. The ins and outs of membrane bending by intrinsically disordered proteins. SCIENCE ADVANCES 2023; 9:eadg3485. [PMID: 37418523 PMCID: PMC10328403 DOI: 10.1126/sciadv.adg3485] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Accepted: 06/07/2023] [Indexed: 07/09/2023]
Abstract
Membrane curvature is essential to diverse cellular functions. While classically attributed to structured domains, recent work illustrates that intrinsically disordered proteins are also potent drivers of membrane bending. Specifically, repulsive interactions among disordered domains drive convex bending, while attractive interactions drive concave bending, creating membrane-bound, liquid-like condensates. How might disordered domains that contain both repulsive and attractive domains affect curvature? Here, we examined chimeras that combined attractive and repulsive interactions. When the attractive domain was closer to the membrane, its condensation amplified steric pressure among repulsive domains, leading to convex curvature. In contrast, when the repulsive domain was closer to the membrane, attractive interactions dominated, resulting in concave curvature. Further, a transition from convex to concave curvature occurred with increasing ionic strength, which reduced repulsion while enhancing condensation. In agreement with a simple mechanical model, these results illustrate a set of design rules for membrane bending by disordered proteins.
Collapse
Affiliation(s)
- Feng Yuan
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, USA
| | - Christopher T. Lee
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, CA, USA
| | - Arjun Sangani
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, USA
| | - Justin R. Houser
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, USA
| | - Liping Wang
- Department of Biochemistry and Structural Biology, The University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Eileen M. Lafer
- Department of Biochemistry and Structural Biology, The University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Padmini Rangamani
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, CA, USA
| | - Jeanne C. Stachowiak
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, USA
- Department of Chemical Engineering, The University of Texas at Austin, Austin, TX, USA
| |
Collapse
|
6
|
Remodeling of the Plasma Membrane by Surface-Bound Protein Monomers and Oligomers: The Critical Role of Intrinsically Disordered Regions. J Membr Biol 2022; 255:651-663. [PMID: 35930019 PMCID: PMC9718270 DOI: 10.1007/s00232-022-00256-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 07/07/2022] [Indexed: 12/24/2022]
Abstract
The plasma membrane (PM) of cells is a dynamic structure whose morphology and composition is in constant flux. PM morphologic changes are particularly relevant for the assembly and disassembly of signaling platforms involving surface-bound signaling proteins, as well as for many other mechanochemical processes that occur at the PM surface. Surface-bound membrane proteins (SBMP) require efficient association with the PM for their function, which is often achieved by the coordinated interactions of intrinsically disordered regions (IDRs) and globular domains with membrane lipids. This review focuses on the role of IDR-containing SBMPs in remodeling the composition and curvature of the PM. The ability of IDR-bearing SBMPs to remodel the Gaussian and mean curvature energies of the PM is intimately linked to their ability to sort subsets of phospholipids into nanoclusters. We therefore discuss how IDRs of many SBMPs encode lipid-binding specificity or facilitate cluster formation, both of which increase their membrane remodeling capacity, and how SBMP oligomers alter membrane shape by monolayer surface area expansion and molecular crowding.
Collapse
|
7
|
Strength in numbers: effect of protein crowding on the shape of cell membranes. Biochem Soc Trans 2022; 50:1257-1267. [PMID: 36214373 DOI: 10.1042/bst20210883] [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: 07/05/2022] [Revised: 09/16/2022] [Accepted: 09/20/2022] [Indexed: 11/17/2022]
Abstract
Continuous reshaping of the plasma membrane into pleomorphic shapes is critical for a plethora of cellular functions. How the cell carries out this enigmatic control of membrane remodeling has remained an active research field for decades and several molecular and biophysical mechanisms have shown to be involved in overcoming the energy barrier associated with membrane bending. The reported mechanisms behind membrane bending have been largely concerned with structural protein features, however, in the last decade, reports on the ability of densely packed proteins to bend membranes by protein-protein crowding, have challenged prevailing mechanistic views. Crowding has now been shown to generate spontaneous vesicle formation and tubular morphologies on cell- and model membranes, demonstrating crowding as a relevant player involved in the bending of membranes. Still, current research is largely based on unnatural overexpression of proteins in non-native domains, and together with efforts in modeling, this has led to questioning the in vivo impact of crowding. In this review, we examine this previously overlooked mechanism by summarizing recent advances in the understanding of protein-protein crowding and its prevalence in cellular membrane-shaping processes.
Collapse
|
8
|
Insights into Membrane Curvature Sensing and Membrane Remodeling by Intrinsically Disordered Proteins and Protein Regions. J Membr Biol 2022; 255:237-259. [PMID: 35451616 PMCID: PMC9028910 DOI: 10.1007/s00232-022-00237-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 03/29/2022] [Indexed: 12/15/2022]
Abstract
Cellular membranes are highly dynamic in shape. They can rapidly and precisely regulate their shape to perform various cellular functions. The protein’s ability to sense membrane curvature is essential in various biological events such as cell signaling and membrane trafficking. As they are bound, these curvature-sensing proteins may also change the local membrane shape by one or more curvature driving mechanisms. Established curvature-sensing/driving mechanisms rely on proteins with specific structural features such as amphipathic helices and intrinsically curved shapes. However, the recent discovery and characterization of many proteins have shattered the protein structure–function paradigm, believing that the protein functions require a unique structural feature. Typically, such structure-independent functions are carried either entirely by intrinsically disordered proteins or hybrid proteins containing disordered regions and structured domains. It is becoming more apparent that disordered proteins and regions can be potent sensors/inducers of membrane curvatures. In this article, we outline the basic features of disordered proteins and regions, the motifs in such proteins that encode the function, membrane remodeling by disordered proteins and regions, and assays that may be employed to investigate curvature sensing and generation by ordered/disordered proteins.
Collapse
|
9
|
Mondal S, Narayan KB, Powers I, Botterbusch S, Baumgart T. Endophilin recruitment drives membrane curvature generation through coincidence detection of GPCR loop interactions and negative lipid charge. J Biol Chem 2021; 296:100140. [PMID: 33268381 PMCID: PMC7948419 DOI: 10.1074/jbc.ra120.016118] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Revised: 11/25/2020] [Accepted: 12/01/2020] [Indexed: 12/23/2022] Open
Abstract
Endophilin plays key roles during endocytosis of cellular receptors, including generating membrane curvature to drive internalization. Electrostatic interactions between endophilin's BIN/Amphiphysin/Rvs domain and anionic membrane lipids have been considered the major driving force in curvature generation. However, the SH3 domain of endophilin also interacts with the proline-rich third intracellular loop (TIL) of various G-protein-coupled receptors (GPCRs), and it is unclear whether this interaction has a direct role in generating membrane curvature during endocytosis. To examine this, we designed model membranes with a membrane density of 1400 receptors per μm2 represented by a covalently conjugated TIL region from the β1-adrenergic receptor. We observed that TIL recruits endophilin to membranes composed of 95 mol% of zwitterionic lipids via the SH3 domain. More importantly, endophilin recruited via TIL tubulates vesicles and gets sorted onto highly curved membrane tubules. These observations indicate that the cellular membrane bending and curvature sensing activities of endophilin can be facilitated through detection of the TIL of activated GPCRs in addition to binding to anionic lipids. Furthermore, we show that TIL electrostatically interacts with membranes composed of anionic lipids. Therefore, anionic lipids can modulate TIL/SH3 domain binding. Overall, our findings imply that an interplay between TIL, charged membrane lipids, BAR domain, and SH3 domain could exist in the biological system and that these components may act in coordination to regulate the internalization of cellular receptors.
Collapse
Affiliation(s)
- Samsuzzoha Mondal
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Karthik B Narayan
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Imania Powers
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Samuel Botterbusch
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Tobias Baumgart
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
| |
Collapse
|
10
|
Houser JR, Hayden CC, Thirumalai D, Stachowiak JC. A Förster Resonance Energy Transfer-Based Sensor of Steric Pressure on Membrane Surfaces. J Am Chem Soc 2020; 142:20796-20805. [PMID: 33237768 PMCID: PMC8274331 DOI: 10.1021/jacs.0c09802] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cellular membranes are densely covered by proteins. Steric pressure generated by protein collisions plays a significant role in shaping and curving biological membranes. However, no method currently exists for measuring steric pressure at membrane surfaces. Here, we developed a sensor based on Förster resonance energy transfer (FRET), which uses the principles of polymer physics to precisely detect changes in steric pressure. The sensor consists of a polyethylene glycol chain tethered to the membrane surface. The polymer has a donor fluorophore at its free end, such that FRET with acceptor fluorophores in the membrane provides a real-time readout of polymer extension. As a demonstration of the sensor, we measured the steric pressure generated by a model protein involved in membrane bending, the N-terminal homology domain (ENTH) of Epsin1. As the membrane becomes crowded by ENTH proteins, the polymer chain extends, increasing the fluorescence lifetime of the donor. Drawing on polymer theory, we use this change in lifetime to calculate steric pressure as a function of membrane coverage by ENTH, validating theoretical equations of state. Further, we find that ENTH's ability to break up larger vesicles into smaller ones correlates with steric pressure rather than the chemistry used to attach ENTH to the membrane surface. This result addresses a long-standing question about the molecular mechanisms of membrane remodeling. More broadly, this sensor makes it possible to measure steric pressure in situ during diverse biochemical events that occur on membrane surfaces, such as membrane remodeling, ligand-receptor binding, assembly of protein complexes, and changes in membrane organization.
Collapse
Affiliation(s)
- Justin R. Houser
- Department of Biomedical Engineering, The University of Texas at Austin
| | - Carl C. Hayden
- Department of Biomedical Engineering, The University of Texas at Austin
| | - D. Thirumalai
- Department of Chemistry, The University of Texas at Austin. USA
| | - Jeanne C. Stachowiak
- Department of Biomedical Engineering, The University of Texas at Austin
- Institute for Cellular and Molecular Biology, The University of Texas at Austin
| |
Collapse
|
11
|
Zhukovsky MA, Filograna A, Luini A, Corda D, Valente C. Protein Amphipathic Helix Insertion: A Mechanism to Induce Membrane Fission. Front Cell Dev Biol 2019; 7:291. [PMID: 31921835 PMCID: PMC6914677 DOI: 10.3389/fcell.2019.00291] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 11/06/2019] [Indexed: 12/19/2022] Open
Abstract
One of the fundamental features of biomembranes is the ability to fuse or to separate. These processes called respectively membrane fusion and fission are central in the homeostasis of events such as those related to intracellular membrane traffic. Proteins that contain amphipathic helices (AHs) were suggested to mediate membrane fission via shallow insertion of these helices into the lipid bilayer. Here we analyze the AH-containing proteins that have been identified as essential for membrane fission and categorize them in few subfamilies, including small GTPases, Atg proteins, and proteins containing either the ENTH/ANTH- or the BAR-domain. AH-containing fission-inducing proteins may require cofactors such as additional proteins (e.g., lipid-modifying enzymes), or lipids (e.g., phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2], phosphatidic acid [PA], or cardiolipin). Both PA and cardiolipin possess a cone shape and a negative charge (-2) that favor the recruitment of the AHs of fission-inducing proteins. Instead, PtdIns(4,5)P2 is characterized by an high negative charge able to recruit basic residues of the AHs of fission-inducing proteins. Here we propose that the AHs of fission-inducing proteins contain sequence motifs that bind lipid cofactors; accordingly (K/R/H)(K/R/H)xx(K/R/H) is a PtdIns(4,5)P2-binding motif, (K/R)x6(F/Y) is a cardiolipin-binding motif, whereas KxK is a PA-binding motif. Following our analysis, we show that the AHs of many fission-inducing proteins possess five properties: (a) at least three basic residues on the hydrophilic side, (b) ability to oligomerize, (c) optimal (shallow) depth of insertion into the membrane, (d) positive cooperativity in membrane curvature generation, and (e) specific interaction with one of the lipids mentioned above. These lipid cofactors favor correct conformation, oligomeric state and optimal insertion depth. The most abundant lipid in a given organelle possessing high negative charge (more negative than -1) is usually the lipid cofactor in the fission event. Interestingly, naturally occurring mutations have been reported in AH-containing fission-inducing proteins and related to diseases such as centronuclear myopathy (amphiphysin 2), Charcot-Marie-Tooth disease (GDAP1), Parkinson's disease (α-synuclein). These findings add to the interest of the membrane fission process whose complete understanding will be instrumental for the elucidation of the pathogenesis of diseases involving mutations in the protein AHs.
Collapse
Affiliation(s)
- Mikhail A. Zhukovsky
- Institute of Biochemistry and Cell Biology, National Research Council, Naples, Italy
| | | | | | - Daniela Corda
- Institute of Biochemistry and Cell Biology, National Research Council, Naples, Italy
| | - Carmen Valente
- Institute of Biochemistry and Cell Biology, National Research Council, Naples, Italy
| |
Collapse
|
12
|
Raghunath G, Dyer RB. Kinetics of Histidine-Tagged Protein Association to Nickel-Decorated Liposome Surfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:12550-12561. [PMID: 31466440 PMCID: PMC6759406 DOI: 10.1021/acs.langmuir.9b01700] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Nickel-chelating lipids offer a convenient platform for reversible immobilization of histidine-tagged proteins to liposome surfaces. This interaction recently found utility as a model system for studying membrane remodeling triggered by protein crowding. Despite its wide array of utility, the molecular details of transient protein association to the lipid surfaces decorated with such chelator lipids remains poorly understood. In this study, we explore the kinetics of protein-liposome association across a wide concentration range using stopped-flow fluorescence. The fluorescence of histidine-tagged protein containing an intrinsic fluorophore (superfolder green fluorescent protein, SfGFP) was quenched upon binding to Ni-NTA-modified liposomes containing the quencher Dabsyl-PE lipids. Stopped-flow fluorescence reveals a complex, multiexponential binding behavior with a fast (kobs ∼ 10-20 s-1) phase and slower (kobs < 4 s-1) phase. Interestingly, the observed rates for the slower phase increase initially under low concentrations but start decreasing once a critical concentration is reached. Despite differences in the binding time scales, we observe that the trend of decreasing rates is reproducible irrespective of the chelator lipid doping level, protein surface charge, or lipid composition. Consideration of the protein footprint and membrane surface area occupancy leads us to conclude that the multiphasic binding behavior is reflective of protein binding via two distinct binding conformations. We propose that preliminary steps in protein association involve binding of a sterically occlusive side-on conformation followed by reorganization that leads to an end-on conformation with increased packing density. These results are important for the improvement of histidine-tag-based immobilization strategies and offer mechanistic insight into intermediates preceding membrane bending driven by protein crowding.
Collapse
|
13
|
Vanuytsel S, Carniello J, Wallace MI. Artificial Signal Transduction across Membranes. Chembiochem 2019; 20:2569-2580. [DOI: 10.1002/cbic.201900254] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 07/09/2019] [Indexed: 12/18/2022]
Affiliation(s)
- Steven Vanuytsel
- Department of ChemistryKing's College London Britannia House 7 Trinity Street London SE1 1DB UK
- London Centre for Nanotechnology Strand London WC2R 2LS UK
| | - Joanne Carniello
- Department of ChemistryKing's College London Britannia House 7 Trinity Street London SE1 1DB UK
- London Centre for Nanotechnology Strand London WC2R 2LS UK
| | - Mark Ian Wallace
- Department of ChemistryKing's College London Britannia House 7 Trinity Street London SE1 1DB UK
- London Centre for Nanotechnology Strand London WC2R 2LS UK
| |
Collapse
|
14
|
Chen J, Kriwacki RW. Intrinsically Disordered Proteins: Structure, Function and Therapeutics. J Mol Biol 2018; 430:2275-2277. [PMID: 29906412 DOI: 10.1016/j.jmb.2018.06.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Jianhan Chen
- Department of Chemistry, University of Massachusetts, Amherst, Amherst, MA 01003, United States; Department of Biochemistry & Molecular Biology, University of Massachusetts, Amherst, Amherst, MA 01003, United States.
| | - Richard W Kriwacki
- Department of Structural Biology, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, United States; Department of Microbiology, Immunology and Biochemistry, University of Tennessee Health Sciences Center, Memphis, TN 38105, United States.
| |
Collapse
|