1
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Smith IN, Dawson JE, Krieger J, Thacker S, Bahar I, Eng C. Structural and Dynamic Effects of PTEN C-Terminal Tail Phosphorylation. J Chem Inf Model 2022; 62:4175-4190. [PMID: 36001481 PMCID: PMC9472802 DOI: 10.1021/acs.jcim.2c00441] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2022] [Indexed: 11/28/2022]
Abstract
The phosphatase and tensin homologue deleted on chromosome 10 (PTEN) tumor suppressor gene encodes a tightly regulated dual-specificity phosphatase that serves as the master regulator of PI3K/AKT/mTOR signaling. The carboxy-terminal tail (CTT) is key to regulation and harbors multiple phosphorylation sites (Ser/Thr residues 380-385). CTT phosphorylation suppresses the phosphatase activity by inducing a stable, closed conformation. However, little is known about the mechanisms of phosphorylation-induced CTT-deactivation dynamics. Using explicit solvent microsecond molecular dynamics simulations, we show that CTT phosphorylation leads to a partially collapsed conformation, which alters the secondary structure of PTEN and induces long-range conformational rearrangements that encompass the active site. The active site rearrangements prevent localization of PTEN to the membrane, precluding lipid phosphatase activity. Notably, we have identified phosphorylation-induced allosteric coupling between the interdomain region and a hydrophobic site neighboring the active site in the phosphatase domain. Collectively, the results provide a mechanistic understanding of CTT phosphorylation dynamics and reveal potential druggable allosteric sites in a previously believed clinically undruggable protein.
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Affiliation(s)
- Iris N. Smith
- Genomic
Medicine Institute, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Avenue, NE-50, Cleveland, Ohio 44195, United States
| | - Jennifer E. Dawson
- Genomic
Medicine Institute, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Avenue, NE-50, Cleveland, Ohio 44195, United States
| | - James Krieger
- Department
of Computational and Systems Biology, University
of Pittsburgh, 800 Murdoch Building, 3420 Forbes Avenue, Pittsburgh, Pennsylvania 15260, United States
| | - Stetson Thacker
- Genomic
Medicine Institute, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Avenue, NE-50, Cleveland, Ohio 44195, United States
- Cleveland
Clinic Lerner College of Medicine, Case
Western Reserve University, 9500 Euclid Avenue, Cleveland, Ohio 44195, United
States
| | - Ivet Bahar
- Department
of Computational and Systems Biology, University
of Pittsburgh, 800 Murdoch Building, 3420 Forbes Avenue, Pittsburgh, Pennsylvania 15260, United States
| | - Charis Eng
- Genomic
Medicine Institute, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Avenue, NE-50, Cleveland, Ohio 44195, United States
- Cleveland
Clinic Lerner College of Medicine, Case
Western Reserve University, 9500 Euclid Avenue, Cleveland, Ohio 44195, United
States
- Case
Comprehensive Cancer Center, Case Western
Reserve University School of Medicine, 10900 Euclid Avenue, Cleveland, Ohio 44106, United States
- Taussig
Cancer Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, Ohio 44195, United States
- Department
of Genetics and Genome Sciences, Case Western
Reserve University School of Medicine, 10900 Euclid Avenue, Cleveland, Ohio 44106, United States
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2
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Larsen A, John L, Sansom M, Corey R. Specific interactions of peripheral membrane proteins with lipids: what can molecular simulations show us? Biosci Rep 2022; 42:BSR20211406. [PMID: 35297484 PMCID: PMC9008707 DOI: 10.1042/bsr20211406] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 03/14/2022] [Accepted: 03/16/2022] [Indexed: 12/04/2022] Open
Abstract
Peripheral membrane proteins (PMPs) can reversibly and specifically bind to biological membranes to carry out functions such as cell signalling, enzymatic activity, or membrane remodelling. Structures of these proteins and of their lipid-binding domains are typically solved in a soluble form, sometimes with a lipid or lipid headgroup at the binding site. To provide a detailed molecular view of PMP interactions with the membrane, computational methods such as molecular dynamics (MD) simulations can be applied. Here, we outline recent attempts to characterise these binding interactions, focusing on both intracellular proteins, such as phosphatidylinositol phosphate (PIP)-binding domains, and extracellular proteins such as glycolipid-binding bacterial exotoxins. We compare methods used to identify and analyse lipid-binding sites from simulation data and highlight recent work characterising the energetics of these interactions using free energy calculations. We describe how improvements in methodologies and computing power will help MD simulations to continue to contribute to this field in the future.
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Affiliation(s)
| | - Laura H. John
- Department of Biochemistry, University of Oxford, Oxford, U.K
| | | | - Robin A. Corey
- Department of Biochemistry, University of Oxford, Oxford, U.K
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3
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Róg T, Girych M, Bunker A. Mechanistic Understanding from Molecular Dynamics in Pharmaceutical Research 2: Lipid Membrane in Drug Design. Pharmaceuticals (Basel) 2021; 14:1062. [PMID: 34681286 PMCID: PMC8537670 DOI: 10.3390/ph14101062] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 10/14/2021] [Accepted: 10/15/2021] [Indexed: 11/17/2022] Open
Abstract
We review the use of molecular dynamics (MD) simulation as a drug design tool in the context of the role that the lipid membrane can play in drug action, i.e., the interaction between candidate drug molecules and lipid membranes. In the standard "lock and key" paradigm, only the interaction between the drug and a specific active site of a specific protein is considered; the environment in which the drug acts is, from a biophysical perspective, far more complex than this. The possible mechanisms though which a drug can be designed to tinker with physiological processes are significantly broader than merely fitting to a single active site of a single protein. In this paper, we focus on the role of the lipid membrane, arguably the most important element outside the proteins themselves, as a case study. We discuss work that has been carried out, using MD simulation, concerning the transfection of drugs through membranes that act as biological barriers in the path of the drugs, the behavior of drug molecules within membranes, how their collective behavior can affect the structure and properties of the membrane and, finally, the role lipid membranes, to which the vast majority of drug target proteins are associated, can play in mediating the interaction between drug and target protein. This review paper is the second in a two-part series covering MD simulation as a tool in pharmaceutical research; both are designed as pedagogical review papers aimed at both pharmaceutical scientists interested in exploring how the tool of MD simulation can be applied to their research and computational scientists interested in exploring the possibility of a pharmaceutical context for their research.
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Affiliation(s)
- Tomasz Róg
- Department of Physics, University of Helsinki, 00014 Helsinki, Finland;
| | - Mykhailo Girych
- Department of Physics, University of Helsinki, 00014 Helsinki, Finland;
| | - Alex Bunker
- Drug Research Program, Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, 00014 Helsinki, Finland;
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4
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Geragotelis AD, Freites JA, Tobias DJ. Anomalous Diffusion of Peripheral Membrane Signaling Proteins from All-Atom Molecular Dynamics Simulations. J Phys Chem B 2021; 125:9990-9998. [PMID: 34459592 DOI: 10.1021/acs.jpcb.1c04905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Peripheral membrane proteins bind transiently to membrane surfaces as part of many signaling pathways. The bound proteins perform two-dimensional (2-D) diffusion on the membrane surface during the recruitment function. To better understand the interplay between the 2-D diffusion of these protein domains and their membrane binding modes, we performed multimicrosecond all-atom molecular dynamics simulations of two regulatory domains, a C2 domain and a pleckstrin homology (PH) domain, in their experimentally determined bound configuration to a lipid bilayer. The protein bound configurations are preserved throughout the simulation trajectories. Both protein domains exhibit anomalous diffusion with distinct features in their dynamics that reflect their different modes of binding. An analysis of their diffusive behavior reveals common features with the diffusion of lipid molecules in lipid bilayers, suggesting that the 2-D motion of protein domains bound to the membrane surface is modulated by the viscoelastic nature of the lipid bilayer.
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Affiliation(s)
- Andrew D Geragotelis
- Department of Chemistry, University of California, Irvine, Irvine, California 92697-2025, United States
| | - J Alfredo Freites
- Department of Chemistry, University of California, Irvine, Irvine, California 92697-2025, United States
| | - Douglas J Tobias
- Department of Chemistry, University of California, Irvine, Irvine, California 92697-2025, United States
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5
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Aleshin AE, Yao Y, Iftikhar A, Bobkov AA, Yu J, Cadwell G, Klein MG, Dong C, Bankston LA, Liddington RC, Im W, Powis G, Marassi FM. Structural basis for the association of PLEKHA7 with membrane-embedded phosphatidylinositol lipids. Structure 2021; 29:1029-1039.e3. [PMID: 33878292 DOI: 10.1016/j.str.2021.03.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 02/15/2021] [Accepted: 03/25/2021] [Indexed: 01/11/2023]
Abstract
PLEKHA7 (pleckstrin homology domain containing family A member 7) plays key roles in intracellular signaling, cytoskeletal organization, and cell adhesion, and is associated with multiple human cancers. The interactions of its pleckstrin homology (PH) domain with membrane phosphatidyl-inositol-phosphate (PIP) lipids are critical for proper cellular localization and function, but little is known about how PLEKHA7 and other PH domains interact with membrane-embedded PIPs. Here we describe the structural basis for recognition of membrane-bound PIPs by PLEHA7. Using X-ray crystallography, nuclear magnetic resonance, molecular dynamics simulations, and isothermal titration calorimetry, we show that the interaction of PLEKHA7 with PIPs is multivalent, distinct from a discrete one-to-one interaction, and induces PIP clustering. Our findings reveal a central role of the membrane assembly in mediating protein-PIP association and provide a roadmap for understanding how the PH domain contributes to the signaling, adhesion, and nanoclustering functions of PLEKHA7.
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Affiliation(s)
- Alexander E Aleshin
- Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Yong Yao
- Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Amer Iftikhar
- Departments of Biological Sciences, Chemistry and Bioengineering, Lehigh University, Bethlehem, PA 18015, USA
| | - Andrey A Bobkov
- Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Jinghua Yu
- Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Gregory Cadwell
- Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Michael G Klein
- Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Chuqiao Dong
- Departments of Biological Sciences, Chemistry and Bioengineering, Lehigh University, Bethlehem, PA 18015, USA
| | - Laurie A Bankston
- Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Robert C Liddington
- Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Wonpil Im
- Departments of Biological Sciences, Chemistry and Bioengineering, Lehigh University, Bethlehem, PA 18015, USA
| | - Garth Powis
- Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Francesca M Marassi
- Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA.
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6
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Pant S, Tajkhorshid E. Microscopic Characterization of GRP1 PH Domain Interaction with Anionic Membranes. J Comput Chem 2020; 41:489-499. [PMID: 31762060 PMCID: PMC7000246 DOI: 10.1002/jcc.26109] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 10/03/2019] [Accepted: 10/15/2019] [Indexed: 01/17/2023]
Abstract
The pleckstrin homology (PH) domain of general receptor for phosphoionositides 1 (GRP1-PHD) binds specifically to phosphatidylinositol (3,4,5)-triphosphate (PIP3 ), and acts as a second messenger. Using an extensive array of molecular dynamics (MD) simulations employing highly mobile membrane mimetic (HMMM) model as well as complementary full membrane simulations, we capture differentiable binding and dynamics of GRP1-PHD in the presence of membranes containing PC, PS, and PIP3 lipids in varying compositions. While GRP1-PHD forms only transient interactions with pure PC membranes, incorporation of anionic lipids resulted in stable membrane-bound configurations. We report the first observation of two distinct PIP3 binding modes on GRP1-PHD, involving PIP3 interactions at a "canonical" and at an "alternate" site, suggesting the possibility of simultaneous binding of multiple anionic lipids. The full membrane simulations confirmed the stability of the membrane bound pose of GRP1-PHD as captured from our HMMM membrane binding simulations. By performing additional steered membrane unbinding simulations and calculating nonequilibrium work associated with the process, as well as metadynamics simulations, on the protein bound to full membranes, allowing for more quantitative examination of the binding strength of the GRP1-PHD to the membrane, we demonstrate that along with the bound PIP3 , surrounding anionic PS lipids increase the energetic cost of unbinding of GRP1-PHD from the canonical mode, causing them to dissociate more slowly than the alternate mode. Our results demonstrate that concurrent binding of multiple anionic lipids by GRP1-PHD contributes to its membrane affinity, which in turn control its signaling activity. © 2019 Wiley Periodicals, Inc.
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Affiliation(s)
- Shashank Pant
- Center for Biophysics and Quantitative Biology, Department of Biochemistry, NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801
| | - Emad Tajkhorshid
- Center for Biophysics and Quantitative Biology, Department of Biochemistry, NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801
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7
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Yamamoto E, Domański J, Naughton FB, Best RB, Kalli AC, Stansfeld PJ, Sansom MSP. Multiple lipid binding sites determine the affinity of PH domains for phosphoinositide-containing membranes. SCIENCE ADVANCES 2020; 6:eaay5736. [PMID: 32128410 PMCID: PMC7030919 DOI: 10.1126/sciadv.aay5736] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Accepted: 12/03/2019] [Indexed: 05/19/2023]
Abstract
Association of peripheral proteins with lipid bilayers regulates membrane signaling and dynamics. Pleckstrin homology (PH) domains bind to phosphatidylinositol phosphate (PIP) molecules in membranes. The effects of local PIP enrichment on the interaction of PH domains with membranes is unclear. Molecular dynamics simulations allow estimation of the binding energy of GRP1 PH domain to PIP3-containing membranes. The free energy of interaction of the PH domain with more than two PIP3 molecules is comparable to experimental values, suggesting that PH domain binding involves local clustering of PIP molecules within membranes. We describe a mechanism of PH binding proceeding via an encounter state to two bound states which differ in the orientation of the protein relative to the membrane, these orientations depending on the local PIP concentration. These results suggest that nanoscale clustering of PIP molecules can control the strength and orientation of PH domain interaction in a concentration-dependent manner.
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Affiliation(s)
- Eiji Yamamoto
- Department of System Design Engineering, Keio University, Yokohama, Kanagawa 223-8522, Japan
| | - Jan Domański
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520, USA
| | - Fiona B. Naughton
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
- Department of Physics, Arizona State University, Tempe, AZ 85287-1504, USA
| | - Robert B. Best
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520, USA
| | - Antreas C. Kalli
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
- Leeds Institute of Cardiovascular and Metabolic Medicine and Astbury Center for Structural Molecular Biology, University of Leeds, Leeds, UK
| | - Phillip J. Stansfeld
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Mark S. P. Sansom
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
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8
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Muller MP, Jiang T, Sun C, Lihan M, Pant S, Mahinthichaichan P, Trifan A, Tajkhorshid E. Characterization of Lipid-Protein Interactions and Lipid-Mediated Modulation of Membrane Protein Function through Molecular Simulation. Chem Rev 2019; 119:6086-6161. [PMID: 30978005 PMCID: PMC6506392 DOI: 10.1021/acs.chemrev.8b00608] [Citation(s) in RCA: 133] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The cellular membrane constitutes one of the most fundamental compartments of a living cell, where key processes such as selective transport of material and exchange of information between the cell and its environment are mediated by proteins that are closely associated with the membrane. The heterogeneity of lipid composition of biological membranes and the effect of lipid molecules on the structure, dynamics, and function of membrane proteins are now widely recognized. Characterization of these functionally important lipid-protein interactions with experimental techniques is however still prohibitively challenging. Molecular dynamics (MD) simulations offer a powerful complementary approach with sufficient temporal and spatial resolutions to gain atomic-level structural information and energetics on lipid-protein interactions. In this review, we aim to provide a broad survey of MD simulations focusing on exploring lipid-protein interactions and characterizing lipid-modulated protein structure and dynamics that have been successful in providing novel insight into the mechanism of membrane protein function.
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Affiliation(s)
- Melanie P. Muller
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology
- Department of Biochemistry
- Center for Biophysics and Quantitative Biology
- College of Medicine
- University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Tao Jiang
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology
- Department of Biochemistry
- Center for Biophysics and Quantitative Biology
- University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Chang Sun
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology
- Department of Biochemistry
- University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Muyun Lihan
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology
- Department of Biochemistry
- Center for Biophysics and Quantitative Biology
- University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Shashank Pant
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology
- Department of Biochemistry
- Center for Biophysics and Quantitative Biology
- University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Paween Mahinthichaichan
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology
- Department of Biochemistry
- University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Anda Trifan
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology
- Department of Biochemistry
- Center for Biophysics and Quantitative Biology
- University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Emad Tajkhorshid
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology
- Department of Biochemistry
- Center for Biophysics and Quantitative Biology
- College of Medicine
- University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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9
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Enkavi G, Javanainen M, Kulig W, Róg T, Vattulainen I. Multiscale Simulations of Biological Membranes: The Challenge To Understand Biological Phenomena in a Living Substance. Chem Rev 2019; 119:5607-5774. [PMID: 30859819 PMCID: PMC6727218 DOI: 10.1021/acs.chemrev.8b00538] [Citation(s) in RCA: 173] [Impact Index Per Article: 34.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
![]()
Biological
membranes are tricky to investigate. They are complex
in terms of molecular composition and structure, functional
over a wide range of time scales, and characterized
by nonequilibrium conditions. Because of all of these
features, simulations are a great technique to study biomembrane
behavior. A significant part of the functional processes
in biological membranes takes place at the molecular
level; thus computer simulations are the method of
choice to explore how their properties emerge from specific
molecular features and how the interplay among the numerous
molecules gives rise to function over spatial and
time scales larger than the molecular ones. In this
review, we focus on this broad theme. We discuss the current
state-of-the-art of biomembrane simulations that, until
now, have largely focused on a rather narrow picture
of the complexity of the membranes. Given this, we
also discuss the challenges that we should unravel in the
foreseeable future. Numerous features such as the actin-cytoskeleton
network, the glycocalyx network, and nonequilibrium
transport under ATP-driven conditions have so far
received very little attention; however, the potential
of simulations to solve them would be exceptionally high. A
major milestone for this research would be that one day
we could say that computer simulations genuinely research
biological membranes, not just lipid bilayers.
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Affiliation(s)
- Giray Enkavi
- Department of Physics , University of Helsinki , P.O. Box 64, FI-00014 Helsinki , Finland
| | - Matti Javanainen
- Department of Physics , University of Helsinki , P.O. Box 64, FI-00014 Helsinki , Finland.,Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences , Flemingovo naḿesti 542/2 , 16610 Prague , Czech Republic.,Computational Physics Laboratory , Tampere University , P.O. Box 692, FI-33014 Tampere , Finland
| | - Waldemar Kulig
- Department of Physics , University of Helsinki , P.O. Box 64, FI-00014 Helsinki , Finland
| | - Tomasz Róg
- Department of Physics , University of Helsinki , P.O. Box 64, FI-00014 Helsinki , Finland.,Computational Physics Laboratory , Tampere University , P.O. Box 692, FI-33014 Tampere , Finland
| | - Ilpo Vattulainen
- Department of Physics , University of Helsinki , P.O. Box 64, FI-00014 Helsinki , Finland.,Computational Physics Laboratory , Tampere University , P.O. Box 692, FI-33014 Tampere , Finland.,MEMPHYS-Center for Biomembrane Physics
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10
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Liu Y, Ebalunode JO, Briggs JM. Insights into the substrate binding specificity of quorum-quenching acylase PvdQ. J Mol Graph Model 2019; 88:104-120. [PMID: 30703686 DOI: 10.1016/j.jmgm.2019.01.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 01/09/2019] [Accepted: 01/10/2019] [Indexed: 01/19/2023]
Abstract
Quorum sensing is a cell to cell signaling mechanism that enables them to coordinate their behaviors in a density-dependent manner mediated by small diffusible signaling molecules, which can control the virulence and biofilm gene expression in many Gram-negative and positive bacteria. N-acyl homoserine lactone acylase PvdQ from human opportunistic pathogen Pseudomonas aeruginosa is a quorum-quenching enzyme that can hydrolyze the amide bond of the quorum signaling N-acyl homoserine lactones (AHLs) thereby degrading the signaling molecules, turning off the biofilm phenotype and resulting in a reduction of bacterial virulence. Previous studies demonstrated that PvdQ has different preferences for N-acyl substrates with different acyl chain lengths and substituents. However, the substrate binding specificity determinants of the quorum-quenching enzyme PvdQ with the different bacterial ligands are unknown and unintuitive. Further, elucidation of these determinants can lead to mutants with efficiency and broader substrate promiscuity. To investigate this question, a computational study was carried out combining multiple molecular docking methods, molecular dynamics simulations, residue interaction network analysis, and binding free energy calculations. The main findings are: firstly, the results from pKa predictions support that the pKa of the N-terminus of Serβ1 was depressed due to the surrounding residues. Multiple molecular docking studies provide useful information about the detailed binding modes and binding affinities. Secondly, 300 ns molecular dynamics simulations were carried out to analyze the overall molecular motions of substrate-bound and substrate-free PvdQ. The specific interactions between the active site of PvdQ and different ligands revealed the determinants for the preference among the ligands. A systematic comparison and analysis of the protein dynamic fingerprint of each complex demonstrated that binding of the most favorable ligand, C12-homoserine lactone (C12-HSL), reduced the global motions of the complex and maintained the correct arrangement of the catalytic site. Further, the residue interaction network analysis of each system illustrated that there are more communication contacts and pathways between the residues in the C12-HSL complex as compared to complexes with the other ligands. The binding of the C12-HSL ligand facilitates structural communication between the two knobs and the active site. While the binding of the other ligands tend to impair specific communication pathways between the two knobs and the active site, and lead to a catalytically inefficient state. Finally, simulation results from free energy landscape and binding free energy analysis revealed that the C12-HSL ligand has the lowest binding free energy and greater stability than the less favored ligands. Each of the following residues: Serβ1, Hisβ23, Pheβ24, Metβ30, Pheβ32, Leuβ50, Asnβ57, Thrβ69, Valβ70, Trpβ162, Trpβ186, Asnβ269, Argβ297 and Leuα146, play different roles in substrate binding specificity. This is the first computational study that provides molecular information for structure-dynamic-function relationships of PvdQ with different ligands and demonstrates determinants of bacterial substrate binding specificity.
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Affiliation(s)
- Yanyun Liu
- Department of Biology and Biochemistry, University of Houston, Houston, TX 77204-5001, USA
| | - Jerry O Ebalunode
- Department of Biology and Biochemistry, University of Houston, Houston, TX 77204-5001, USA
| | - James M Briggs
- Department of Biology and Biochemistry, University of Houston, Houston, TX 77204-5001, USA.
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11
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Pemberton JG, Balla T. Polyphosphoinositide-Binding Domains: Insights from Peripheral Membrane and Lipid-Transfer Proteins. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1111:77-137. [PMID: 30483964 DOI: 10.1007/5584_2018_288] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Within eukaryotic cells, biochemical reactions need to be organized on the surface of membrane compartments that use distinct lipid constituents to dynamically modulate the functions of integral proteins or influence the selective recruitment of peripheral membrane effectors. As a result of these complex interactions, a variety of human pathologies can be traced back to improper communication between proteins and membrane surfaces; either due to mutations that directly alter protein structure or as a result of changes in membrane lipid composition. Among the known structural lipids found in cellular membranes, phosphatidylinositol (PtdIns) is unique in that it also serves as the membrane-anchored precursor of low-abundance regulatory lipids, the polyphosphoinositides (PPIn), which have restricted distributions within specific subcellular compartments. The ability of PPIn lipids to function as signaling platforms relies on both non-specific electrostatic interactions and the selective stereospecific recognition of PPIn headgroups by specialized protein folds. In this chapter, we will attempt to summarize the structural diversity of modular PPIn-interacting domains that facilitate the reversible recruitment and conformational regulation of peripheral membrane proteins. Outside of protein folds capable of capturing PPIn headgroups at the membrane interface, recent studies detailing the selective binding and bilayer extraction of PPIn species by unique functional domains within specific families of lipid-transfer proteins will also be highlighted. Overall, this overview will help to outline the fundamental physiochemical mechanisms that facilitate localized interactions between PPIn lipids and the wide-variety of PPIn-binding proteins that are essential for the coordinate regulation of cellular metabolism and membrane dynamics.
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Affiliation(s)
- Joshua G Pemberton
- Section on Molecular Signal Transduction, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Tamas Balla
- Section on Molecular Signal Transduction, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA.
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12
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Darvill N, Dubois DJ, Rouse SL, Hammoudi PM, Blake T, Benjamin S, Liu B, Soldati-Favre D, Matthews S. Structural Basis of Phosphatidic Acid Sensing by APH in Apicomplexan Parasites. Structure 2018; 26:1059-1071.e6. [PMID: 29910186 PMCID: PMC6084407 DOI: 10.1016/j.str.2018.05.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 03/26/2018] [Accepted: 05/08/2018] [Indexed: 10/29/2022]
Abstract
Plasmodium falciparum and Toxoplasma gondii are obligate intracellular parasites that belong to the phylum of Apicomplexa and cause major human diseases. Their access to an intracellular lifestyle is reliant on the coordinated release of proteins from the specialized apical organelles called micronemes and rhoptries. A specific phosphatidic acid effector, the acylated pleckstrin homology domain-containing protein (APH) plays a central role in microneme exocytosis and thus is essential for motility, cell entry, and egress. TgAPH is acylated on the surface of the micronemes and recruited to phosphatidic acid (PA)-enriched membranes. Here, we dissect the atomic details of APH PA-sensing hub and its functional interaction with phospholipid membranes. We unravel the key determinant of PA recognition for the first time and show that APH inserts into and clusters multiple phosphate head-groups at the bilayer binding surface.
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Affiliation(s)
- Nick Darvill
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London SW7 2AZ, UK
| | - David J Dubois
- Department of Microbiology & Molecular Medicine, Faculty of Medicine, University of Geneva, 1 Rue Michel-Servet, 1211 Geneva, Switzerland
| | - Sarah L Rouse
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London SW7 2AZ, UK
| | - Pierre-Mehdi Hammoudi
- Department of Microbiology & Molecular Medicine, Faculty of Medicine, University of Geneva, 1 Rue Michel-Servet, 1211 Geneva, Switzerland
| | - Tom Blake
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London SW7 2AZ, UK
| | - Stefi Benjamin
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London SW7 2AZ, UK
| | - Bing Liu
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London SW7 2AZ, UK; BioBank, First Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an, 710049, P. R. China
| | - Dominique Soldati-Favre
- Department of Microbiology & Molecular Medicine, Faculty of Medicine, University of Geneva, 1 Rue Michel-Servet, 1211 Geneva, Switzerland.
| | - Steve Matthews
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London SW7 2AZ, UK; BioBank, First Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an, 710049, P. R. China.
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13
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Naughton FB, Kalli AC, Sansom MS. Modes of Interaction of Pleckstrin Homology Domains with Membranes: Toward a Computational Biochemistry of Membrane Recognition. J Mol Biol 2018; 430:372-388. [DOI: 10.1016/j.jmb.2017.12.011] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Revised: 12/08/2017] [Accepted: 12/13/2017] [Indexed: 11/30/2022]
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14
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Feng J, He L, Li Y, Xiao F, Hu G. Modeling of PH Domains and Phosphoinositides Interactions and Beyond. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1111:19-32. [DOI: 10.1007/5584_2018_236] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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15
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Yamamoto E. Computational and theoretical approaches for studies of a lipid recognition protein on biological membranes. Biophys Physicobiol 2017; 14:153-160. [PMID: 29159013 PMCID: PMC5689545 DOI: 10.2142/biophysico.14.0_153] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 09/26/2017] [Indexed: 01/13/2023] Open
Abstract
Many cellular functions, including cell signaling and related events, are regulated by the association of peripheral membrane proteins (PMPs) with biological membranes containing anionic lipids, e.g., phosphatidylinositol phosphate (PIP). This association is often mediated by lipid recognition modules present in many PMPs. Here, I summarize computational and theoretical approaches to investigate the molecular details of the interactions and dynamics of a lipid recognition module, the pleckstrin homology (PH) domain, on biological membranes. Multiscale molecular dynamics simulations using combinations of atomistic and coarse-grained models yielded results comparable to those of actual experiments and could be used to elucidate the molecular mechanisms of the formation of protein/lipid complexes on membrane surfaces, which are often difficult to obtain using experimental techniques. Simulations revealed some modes of membrane localization and interactions of PH domains with membranes in addition to the canonical binding mode. In the last part of this review, I address the dynamics of PH domains on the membrane surface. Local PIP clusters formed around the proteins exhibit anomalous fluctuations. This dynamic change in protein-lipid interactions cause temporally fluctuating diffusivity of proteins, i.e., the short-term diffusivity of the bound protein changes substantially with time, and may in turn contribute to the formation/dissolution of protein complexes in membranes.
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Affiliation(s)
- Eiji Yamamoto
- Graduate School of Science and Technology, Keio University, Yokohama, Kanagawa 223-8522, Japan
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16
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Ray A, Jatana N, Thukral L. Lipidated proteins: Spotlight on protein-membrane binding interfaces. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2017; 128:74-84. [DOI: 10.1016/j.pbiomolbio.2017.01.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 12/29/2016] [Accepted: 01/05/2017] [Indexed: 01/21/2023]
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17
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Khadka B, Gupta RS. Identification of a conserved 8 aa insert in the PIP5K protein in the Saccharomycetaceae family of fungi and the molecular dynamics simulations and structural analysis to investigate its potential functional role. Proteins 2017; 85:1454-1467. [PMID: 28407364 DOI: 10.1002/prot.25306] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 04/06/2017] [Accepted: 04/10/2017] [Indexed: 12/29/2022]
Abstract
Homologs of the phosphatidylinositol-4-phosphate-5-kinase (PIP5K), which controls a multitude of essential cellular functions, contain a 8 aa insert in a conserved region that is specific for the Saccharomycetaceae family of fungi. Using structures of human PIP4K proteins as templates, structural models were generated of the Saccharomyces cerevisiae and human PIP5K proteins. In the modeled S. cerevisiae PIP5K, the 8 aa insert forms a surface exposed loop, present on the same face of the protein as the activation loop of the kinase domain. Electrostatic potential analysis indicates that the residues from 8 aa conserved loop form a highly positively charged surface patch, which through electrostatic interaction with the anionic portions of phospholipid head groups, is expected to play a role in the membrane interaction of the yeast PIP5K. To unravel this prediction, molecular dynamics (MD) simulations were carried out to examine the binding interaction of PIP5K, either containing or lacking the conserved signature insert, with two different membrane lipid bilayers. The results from MD studies provide insights concerning the mechanistic of interaction of PIP5K with lipid bilayer, and support the contention that the identified 8 aa conserved insert in fungal PIP5K plays an important role in the binding of this protein with membrane surface. Proteins 2017; 85:1454-1467. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Bijendra Khadka
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada, L8N 3Z5
| | - Radhey S Gupta
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada, L8N 3Z5
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18
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Chan KC, Lu L, Sun F, Fan J. Molecular Details of the PH Domain of ACAP1BAR-PH Protein Binding to PIP-Containing Membrane. J Phys Chem B 2017; 121:3586-3596. [DOI: 10.1021/acs.jpcb.6b09563] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Kevin Chun Chan
- Department
of Physics and Materials Science, City University of Hong Kong, Hong Kong, China
| | - Lanyuan Lu
- School
of Biological Sciences, Nanyang Technological University, 639798, Singapore
| | - Fei Sun
- National
Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
- Center
for Biological Imaging, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Jun Fan
- Department
of Physics and Materials Science, City University of Hong Kong, Hong Kong, China
- City University of Hong Kong Shenzhen Research Institute, Shenzhen 518057, China
- Center for
Advanced Nuclear Safety and Sustainable Development, City University of Hong Kong, Hong Kong, China
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19
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Structure and lipid-binding properties of the kindlin-3 pleckstrin homology domain. Biochem J 2016; 474:539-556. [PMID: 27974389 PMCID: PMC5290484 DOI: 10.1042/bcj20160791] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 12/04/2016] [Accepted: 12/14/2016] [Indexed: 12/11/2022]
Abstract
Kindlins co-activate integrins alongside talin. They possess, like talin, a FERM domain (4.1-erythrin–radixin–moiesin domain) comprising F0–F3 subdomains, but with a pleckstrin homology (PH) domain inserted in the F2 subdomain that enables membrane association. We present the crystal structure of murine kindlin-3 PH domain determined at a resolution of 2.23 Å and characterise its lipid binding using biophysical and computational approaches. Molecular dynamics simulations suggest flexibility in the PH domain loops connecting β-strands forming the putative phosphatidylinositol phosphate (PtdInsP)-binding site. Simulations with PtdInsP-containing bilayers reveal that the PH domain associates with PtdInsP molecules mainly via the positively charged surface presented by the β1–β2 loop and that it binds with somewhat higher affinity to PtdIns(3,4,5)P3 compared with PtdIns(4,5)P2. Surface plasmon resonance (SPR) with lipid headgroups immobilised and the PH domain as an analyte indicate affinities of 300 µM for PtdIns(3,4,5)P3 and 1 mM for PtdIns(4,5)P2. In contrast, SPR studies with an immobilised PH domain and lipid nanodiscs as the analyte show affinities of 0.40 µM for PtdIns(3,4,5)P3 and no affinity for PtdIns(4,5)P2 when the inositol phosphate constitutes 5% of the total lipids (∼5 molecules per nanodisc). Reducing the PtdIns(3,4,5)P3 composition to 1% abolishes nanodisc binding to the PH domain, as does site-directed mutagenesis of two lysines within the β1–β2 loop. Binding of PtdIns(3,4,5)P3 by a canonical PH domain, Grp1, is not similarly influenced by SPR experimental design. These data suggest a role for PtdIns(3,4,5)P3 clustering in the binding of some PH domains and not others, highlighting the importance of lipid mobility and clustering for the biophysical assessment of protein–membrane interactions.
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20
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Van Aelst B, Devloo R, Zachée P, t'Kindt R, Sandra K, Vandekerckhove P, Compernolle V, Feys HB. Psoralen and Ultraviolet A Light Treatment Directly Affects Phosphatidylinositol 3-Kinase Signal Transduction by Altering Plasma Membrane Packing. J Biol Chem 2016; 291:24364-24376. [PMID: 27687726 DOI: 10.1074/jbc.m116.735126] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 09/17/2016] [Indexed: 01/15/2023] Open
Abstract
Psoralen and ultraviolet A light (PUVA) are used to kill pathogens in blood products and as a treatment of aberrant cell proliferation in dermatitis, cutaneous T-cell lymphoma, and graft-versus-host disease. DNA damage is well described, but the direct effects of PUVA on cell signal transduction are poorly understood. Because platelets are anucleate and contain archetypal signal transduction machinery, they are ideally suited to address this. Lipidomics on platelet membrane extracts showed that psoralen forms adducts with unsaturated carbon bonds of fatty acyls in all major phospholipid classes after PUVA. Such adducts increased lipid packing as measured by a blue shift of an environment-sensitive fluorescent probe in model liposomes. Furthermore, the interaction of these liposomes with lipid order-sensitive proteins like amphipathic lipid-packing sensor and α-synuclein was inhibited by PUVA. In platelets, PUVA caused poor membrane binding of Akt and Bruton's tyrosine kinase effectors following activation of the collagen glycoprotein VI and thrombin protease-activated receptor (PAR) 1. This resulted in defective Akt phosphorylation despite unaltered phosphatidylinositol 3,4,5-trisphosphate levels. Downstream integrin activation was furthermore affected similarly by PUVA following PAR1 (effective half-maximal concentration (EC50), 8.4 ± 1.1 versus 4.3 ± 1.1 μm) and glycoprotein VI (EC50, 1.61 ± 0.85 versus 0.26 ± 0.21 μg/ml) but not PAR4 (EC50, 50 ± 1 versus 58 ± 1 μm) signal transduction. Our findings were confirmed in T-cells from graft-versus-host disease patients treated with extracorporeal photopheresis, a form of systemic PUVA. In conclusion, PUVA increases the order of lipid phases by covalent modification of phospholipids, thereby inhibiting membrane recruitment of effector kinases.
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Affiliation(s)
- Britt Van Aelst
- From the Transfusion Research Center, Belgian Red Cross-Flanders, 9000 Ghent, Belgium
| | - Rosalie Devloo
- From the Transfusion Research Center, Belgian Red Cross-Flanders, 9000 Ghent, Belgium
| | - Pierre Zachée
- the Department of Hematology, Hospital Network Antwerp, 2000 Antwerp, Belgium
| | - Ruben t'Kindt
- the Research Institute for Chromatography, 8500 Kortrijk, Belgium
| | - Koen Sandra
- the Research Institute for Chromatography, 8500 Kortrijk, Belgium
| | - Philippe Vandekerckhove
- the Blood Service of the Belgian Red Cross-Flanders, 2800 Mechelen, Belgium,; the Department of Public Health and Primary Care, KULeuven, 3000 Leuven, Belgium, and; the Faculty of Medicine and Health Sciences, Ghent University, 9000 Ghent, Belgium
| | - Veerle Compernolle
- From the Transfusion Research Center, Belgian Red Cross-Flanders, 9000 Ghent, Belgium,; the Blood Service of the Belgian Red Cross-Flanders, 2800 Mechelen, Belgium,; the Faculty of Medicine and Health Sciences, Ghent University, 9000 Ghent, Belgium
| | - Hendrik B Feys
- From the Transfusion Research Center, Belgian Red Cross-Flanders, 9000 Ghent, Belgium,.
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21
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Thukral L, Sengupta D, Ramkumar A, Murthy D, Agrawal N, Gokhale RS. The Molecular Mechanism Underlying Recruitment and Insertion of Lipid-Anchored LC3 Protein into Membranes. Biophys J 2016; 109:2067-78. [PMID: 26588566 DOI: 10.1016/j.bpj.2015.09.022] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Revised: 09/03/2015] [Accepted: 09/18/2015] [Indexed: 11/16/2022] Open
Abstract
Lipid modification of cytoplasmic proteins initiates membrane engagement that triggers diverse cellular processes. Despite the abundance of lipidated proteins in the human proteome, the key determinants underlying membrane recognition and insertion are poorly understood. Here, we define the course of spontaneous membrane insertion of LC3 protein modified with phosphatidylethanolamine using multiple coarse-grain simulations. The partitioning of the lipid anchor chains proceeds through a concerted process, with its two acyl chains inserting one after the other. Concurrently, a conformational rearrangement involving the α-helix III of LC3, especially in the three basic residues Lys65, Arg68, and Arg69, ensures stable insertion of the phosphatidylethanolamine anchor into membranes. Mutational studies validate the crucial role of these residues, and further live-cell imaging analysis shows a substantial reduction in the formation of autophagic vesicles for the mutant proteins. Our study captures the process of water-favored LC3 protein recruitment to the membrane and thus opens, to our knowledge, new avenues to explore the cellular dynamics underlying vesicular trafficking.
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Affiliation(s)
- Lipi Thukral
- CSIR-Institute of Genomics and Integrative Biology (IGIB), New Delhi, India.
| | | | - Amrita Ramkumar
- CSIR-Institute of Genomics and Integrative Biology (IGIB), New Delhi, India
| | - Divya Murthy
- CSIR-Institute of Genomics and Integrative Biology (IGIB), New Delhi, India
| | - Nikhil Agrawal
- CSIR-Institute of Genomics and Integrative Biology (IGIB), New Delhi, India
| | - Rajesh S Gokhale
- CSIR-Institute of Genomics and Integrative Biology (IGIB), New Delhi, India.
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22
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Buyan A, Kalli AC, Sansom MSP. Multiscale Simulations Suggest a Mechanism for the Association of the Dok7 PH Domain with PIP-Containing Membranes. PLoS Comput Biol 2016; 12:e1005028. [PMID: 27459095 PMCID: PMC4961371 DOI: 10.1371/journal.pcbi.1005028] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 06/20/2016] [Indexed: 11/18/2022] Open
Abstract
Dok7 is a peripheral membrane protein that is associated with the MuSK receptor tyrosine kinase. Formation of the Dok7/MuSK/membrane complex is required for the activation of MuSK. This is a key step in the complex exchange of signals between neuron and muscle, which lead to neuromuscular junction formation, dysfunction of which is associated with congenital myasthenic syndromes. The Dok7 structure consists of a Pleckstrin Homology (PH) domain and a Phosphotyrosine Binding (PTB) domain. The mechanism of the Dok7 association with the membrane remains largely unknown. Using multi-scale molecular dynamics simulations we have explored the formation of the Dok7 PH/membrane complex. Our simulations indicate that the PH domain of Dok7 associates with membranes containing phosphatidylinositol phosphates (PIPs) via interactions of the β1/β2, β3/β4, and β5/β6 loops, which together form a positively charged surface on the PH domain and interact with the negatively charged headgroups of PIP molecules. The initial encounter of the Dok7 PH domain is followed by formation of additional interactions with the lipid bilayer, and especially with PIP molecules, which stabilizes the Dok7 PH/membrane complex. We have quantified the binding of the PH domain to the model bilayers by calculating a density landscape for protein/membrane interactions. Detailed analysis of the PH/PIP interactions reveal both a canonical and an atypical site to be occupied by the anionic lipid. PH domain binding leads to local clustering of PIP molecules in the bilayer. Association of the Dok7 PH domain with PIP lipids is therefore seen as a key step in localization of Dok7 to the membrane and formation of a complex with MuSK. Neuromuscular junction formation and maintenance is an essential biological process, the disruption of which leads to congenital myasthenic syndromes and premature death. Dok7 is a key member in formation, maintenance and signaling in neuromuscular junctions. Dok7 is a peripheral membrane protein that is necessary for full activation of the receptor tyrosine kinase MuSK, a receptor tyrosine kinase residing in the postsynaptic membrane. The structure of Dok7 consists of both a PH domain and a PTB domain. The interaction of Dok7 with cell membranes is not well understood. Here, we use molecular simulations to show that the Dok7 PH domain preferentially binds to PIP lipid molecules when associating with a membrane. Dok7 interacts with the bilayer in both a canonical binding mode and an alternative binding mode. Our simulations also demonstrate the presence of both a canonical and an atypical binding site for PIPs in agreement with recent crystallographic studies of the ASAP1 PH domain. Analysis of density landscapes for the interaction of the Dok7 PH domain with PIP-containing lipid bilayers is also able to identify both canonical and alternative binding modes. Our improved understanding of how Dok7 interacts with a membrane is key to examining Dok7/MuSK signaling.
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Affiliation(s)
- Amanda Buyan
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Antreas C. Kalli
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Mark S. P. Sansom
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
- * E-mail:
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23
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Yamamoto E, Kalli AC, Yasuoka K, Sansom MSP. Interactions of Pleckstrin Homology Domains with Membranes: Adding Back the Bilayer via High-Throughput Molecular Dynamics. Structure 2016; 24:1421-1431. [PMID: 27427480 PMCID: PMC4975593 DOI: 10.1016/j.str.2016.06.002] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Revised: 05/10/2016] [Accepted: 06/02/2016] [Indexed: 12/12/2022]
Abstract
A molecular simulation pipeline for determining the mode of interaction of pleckstrin homology (PH) domains with phosphatidylinositol phosphate (PIP)-containing lipid bilayers is presented. We evaluate our methodology for the GRP1 PH domain via comparison with structural and biophysical data. Coarse-grained simulations yield a 2D density landscape for PH/membrane interactions alongside residue contact profiles. Predictions of the membrane localization and interactions of 13 PH domains reveal canonical, non-canonical, and dual PIP-binding sites on the proteins. Thus, the PH domains associate with the PIP molecules in the membrane via a highly positively charged loop. Some PH domains exhibit modes of interaction with PIP-containing membranes additional to this canonical binding mode. All 13 PH domains cause a degree of local clustering of PIP molecules upon binding to the membrane. This provides a global picture of PH domain interactions with membranes. The high-throughput approach could be extended to other families of peripheral membrane proteins.
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Affiliation(s)
- Eiji Yamamoto
- Department of Mechanical Engineering, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama-shi, Kanagawa-ken 223-8522, Japan
| | - Antreas C Kalli
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK.
| | - Kenji Yasuoka
- Department of Mechanical Engineering, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama-shi, Kanagawa-ken 223-8522, Japan
| | - Mark S P Sansom
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK.
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24
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Goh BC, Wu H, Rynkiewicz MJ, Schulten K, Seaton BA, McCormack FX. Elucidation of Lipid Binding Sites on Lung Surfactant Protein A Using X-ray Crystallography, Mutagenesis, and Molecular Dynamics Simulations. Biochemistry 2016; 55:3692-701. [PMID: 27324153 PMCID: PMC5663190 DOI: 10.1021/acs.biochem.6b00048] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Surfactant protein A (SP-A) is a collagenous C-type lectin (collectin) that is critical for pulmonary defense against inhaled microorganisms. Bifunctional avidity of SP-A for pathogen-associated molecular patterns (PAMPs) such as lipid A and for dipalmitoylphosphatidylcholine (DPPC), the major component of surfactant membranes lining the air-liquid interface of the lung, ensures that the protein is poised for first-line interactions with inhaled pathogens. To improve our understanding of the motifs that are required for interactions with microbes and surfactant structures, we explored the role of the tyrosine-rich binding surface on the carbohydrate recognition domain of SP-A in the interaction with DPPC and lipid A using crystallography, site-directed mutagenesis, and molecular dynamics simulations. Critical binding features for DPPC binding include a three-walled tyrosine cage that binds the choline headgroup through cation-π interactions and a positively charged cluster that binds the phosphoryl group. This basic cluster is also critical for binding of lipid A, a bacterial PAMP and target for SP-A. Molecular dynamics simulations further predict that SP-A binds lipid A more tightly than DPPC. These results suggest that the differential binding properties of SP-A favor transfer of the protein from surfactant DPPC to pathogen membranes containing appropriate lipid PAMPs to effect key host defense functions.
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Affiliation(s)
- Boon Chong Goh
- Beckman Institute and Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL, 61801
| | - Huixing Wu
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Internal Medicine, The University of Cincinnati, Cincinnati, OH 45267
| | - Michael J. Rynkiewicz
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, MA 02118
| | - Klaus Schulten
- Beckman Institute and Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL, 61801,To whom correspondence should be addressed: Dr. Francis X. McCormack, Division of Pulmonary, Critical Care and Sleep Medicine, Department of Internal Medicine, MSB 6165, 231 Albert Sabin Way, University of Cincinnati, OH 45267-0564; Telephone: 513-484-5697, Fax: 513-558-4858, , and Dr. Klaus Schulten, Beckman Institute, University of Illinois, 405 N. Mathews, Urbana IL 61801; Telephone: 217-244-1604, Fax: 217-244-6078,
| | - Barbara A. Seaton
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, MA 02118
| | - Francis X. McCormack
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Internal Medicine, The University of Cincinnati, Cincinnati, OH 45267,To whom correspondence should be addressed: Dr. Francis X. McCormack, Division of Pulmonary, Critical Care and Sleep Medicine, Department of Internal Medicine, MSB 6165, 231 Albert Sabin Way, University of Cincinnati, OH 45267-0564; Telephone: 513-484-5697, Fax: 513-558-4858, , and Dr. Klaus Schulten, Beckman Institute, University of Illinois, 405 N. Mathews, Urbana IL 61801; Telephone: 217-244-1604, Fax: 217-244-6078,
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25
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Naughton FB, Kalli AC, Sansom MSP. Association of Peripheral Membrane Proteins with Membranes: Free Energy of Binding of GRP1 PH Domain with Phosphatidylinositol Phosphate-Containing Model Bilayers. J Phys Chem Lett 2016; 7:1219-24. [PMID: 26977543 PMCID: PMC5593124 DOI: 10.1021/acs.jpclett.6b00153] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Understanding the energetics of peripheral protein-membrane interactions is important to many areas of biophysical chemistry and cell biology. Estimating free-energy landscapes by molecular dynamics (MD) simulation is challenging for such systems, especially when membrane recognition involves complex lipids, e.g., phosphatidylinositol phosphates (PIPs). We combined coarse-grained MD simulations with umbrella sampling to quantify the binding of the well-explored GRP1 pleckstrin homology (PH) domain to model membranes containing PIP molecules. The experimentally observed preference of GRP1-PH for PIP3 over PIP2 was reproduced. Mutation of a key residue (K273A) within the canonical PIP-binding site significantly reduced the free energy of PIP binding. The presence of a noncanonical PIP-interaction site, observed experimentally in other PH domains but not previously in GRP1-PH, was also revealed. These studies demonstrate how combining coarse-grained simulations and umbrella sampling can unmask the molecular basis of the energetics of interactions between peripheral membrane proteins and complex cellular membranes.
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Affiliation(s)
- Fiona B. Naughton
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, U.K
| | - Antreas C. Kalli
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, U.K
| | - Mark S. P. Sansom
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, U.K
- to whom correspondence should be addressed
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26
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Kuang G, Bulone V, Tu Y. Computational studies of the binding profile of phosphoinositide PtdIns (3,4,5) P₃ with the pleckstrin homology domain of an oomycete cellulose synthase. Sci Rep 2016; 6:20555. [PMID: 26857031 PMCID: PMC4746654 DOI: 10.1038/srep20555] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Accepted: 01/06/2016] [Indexed: 12/05/2022] Open
Abstract
Saprolegnia monoica is a model organism to investigate Saprolegnia parasitica, an important oomycete which causes considerable loss in aquaculture every year. S. monoica contains cellulose synthases vital for oomycete growth. However, the molecular mechanism of the cellulose biosynthesis process in the oomycete growth is still poorly understood. Some cellulose synthases of S. monoica, such as SmCesA2, are found to contain a plecsktrin homology (PH) domain, which is a protein module widely found in nature and known to bind to phosphoinositides, a class of signaling compounds involved in many biological processes. Understanding the molecular interactions between the PH domain and phosphoinositides would help to unravel the cellulose biosynthesis process of oomycetes. In this work, the binding profile of PtdIns (3,4,5) P3, a typical phosphoinositide, with SmCesA2-PH was studied by molecular docking, molecular dynamics and metadynamics simulations. PtdIns (3,4,5) P3 is found to bind at a specific site located at β1, β2 and β1-β2 loop of SmCesA2-PH. The high affinity of PtdIns (3,4,5) P3 to SmCesA2-PH is contributed by the free phosphate groups, which have electrostatic and hydrogen-bond interactions with Lys88, Lys100 and Arg102 in the binding site.
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Affiliation(s)
- Guanglin Kuang
- Division of Theoretical Chemistry and Biology, School of Biotechnology, Royal Institute of Technology (KTH), AlbaNova University Center, Stockholm, 106 91, Sweden
| | - Vincent Bulone
- Division of Glycoscience, School of Biotechnology, Royal Institute of Technology (KTH), AlbaNova University Center, Stockholm, 106 91, Sweden
| | - Yaoquan Tu
- Division of Theoretical Chemistry and Biology, School of Biotechnology, Royal Institute of Technology (KTH), AlbaNova University Center, Stockholm, 106 91, Sweden
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27
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Computational Analysis of the Binding Specificities of PH Domains. BIOMED RESEARCH INTERNATIONAL 2015; 2015:792904. [PMID: 26881206 PMCID: PMC4735990 DOI: 10.1155/2015/792904] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 12/13/2015] [Accepted: 12/17/2015] [Indexed: 12/15/2022]
Abstract
Pleckstrin homology (PH) domains share low sequence identities but extremely conserved structures. They have been found in many proteins for cellular signal-dependent membrane targeting by binding inositol phosphates to perform different physiological functions. In order to understand the sequence-structure relationship and binding specificities of PH domains, quantum mechanical (QM) calculations and sequence-based combined with structure-based binding analysis were employed in our research. In the structural aspect, the binding specificities were shown to correlate with the hydropathy characteristics of PH domains and electrostatic properties of the bound inositol phosphates. By comparing these structure properties with sequence-based profiles of physicochemical properties, PH domains can be classified into four functional subgroups according to their binding specificities and affinities to inositol phosphates. The method not only provides a simple and practical paradigm to predict binding specificities for functional genomic research but also gives new insight into the understanding of the basis of diseases with respect to PH domain structures.
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28
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Anomalous Dynamics of a Lipid Recognition Protein on a Membrane Surface. Sci Rep 2015; 5:18245. [PMID: 26657413 PMCID: PMC4677404 DOI: 10.1038/srep18245] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Accepted: 11/11/2015] [Indexed: 12/12/2022] Open
Abstract
Pleckstrin homology (PH) domains are lipid-binding modules present in peripheral membrane proteins which interact with phosphatidyl-inositol phosphates (PIPs) in cell membranes. We use multiscale molecular dynamics simulations to characterize the localization and anomalous dynamics of the DAPP1 PH domain on the surface of a PIP-containing lipid bilayer. Both translational and rotational diffusion of the PH domain on the lipid membrane surface exhibit transient subdiffusion, with an exponent α ≈ 0.5 for times of less than 10 ns. In addition to a PIP3 molecule at the canonical binding site of the PH domain, we observe additional PIP molecules in contact with the protein. Fluctuations in the number of PIPs associated with the PH domain exhibit 1/f noise. We suggest that the anomalous diffusion and long-term correlated interaction of the PH domain with the membrane may contribute to an enhanced probability of encounter with target complexes on cell membrane surfaces.
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29
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Pang X, Fan J, Zhang Y, Zhang K, Gao B, Ma J, Li J, Deng Y, Zhou Q, Egelman EH, Hsu VW, Sun F. A PH domain in ACAP1 possesses key features of the BAR domain in promoting membrane curvature. Dev Cell 2014; 31:73-86. [PMID: 25284369 PMCID: PMC4198613 DOI: 10.1016/j.devcel.2014.08.020] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Revised: 08/12/2014] [Accepted: 08/21/2014] [Indexed: 11/29/2022]
Abstract
The BAR (Bin-Amphiphysin-Rvs) domain undergoes dimerization to produce a curved protein structure, which superimposes onto membrane through electrostatic interactions to sense and impart membrane curvature. In some cases, a BAR domain also possesses an amphipathic helix that inserts into the membrane to induce curvature. ACAP1 (Arfgap with Coil coil, Ankyrin repeat, and PH domain protein 1) contains a BAR domain. Here, we show that this BAR domain can neither bind membrane nor impart curvature, but instead requires a neighboring PH (Pleckstrin Homology) domain to achieve these functions. Specific residues within the PH domain are responsible for both membrane binding and curvature generation. The BAR domain adjacent to the PH domain instead interacts with the BAR domains of neighboring ACAP1 proteins to enable clustering at the membrane. Thus, we have uncovered the molecular basis for an unexpected and unconventional collaboration between PH and BAR domains in membrane bending.
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Affiliation(s)
- Xiaoyun Pang
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jun Fan
- Department of Physics and Materials Science, City University of Hong Kong, Hong Kong 999077, China
| | - Yan Zhang
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Kai Zhang
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Bingquan Gao
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jun Ma
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jian Li
- Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital, Boston, MA 02115, USA; Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
| | - Yuchen Deng
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qiangjun Zhou
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Edward H Egelman
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22908, USA
| | - Victor W Hsu
- Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital, Boston, MA 02115, USA; Department of Medicine, Harvard Medical School, Boston, MA 02115, USA.
| | - Fei Sun
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; Center for Biological Imaging, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
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30
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Chng CP, Strange RW. Lipid-associated aggregate formation of superoxide dismutase-1 is initiated by membrane-targeting loops. Proteins 2014; 82:3194-209. [PMID: 25212695 DOI: 10.1002/prot.24688] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Revised: 08/25/2014] [Accepted: 09/07/2014] [Indexed: 01/02/2023]
Abstract
Copper-Zinc superoxide dismutase 1 (SOD1) is a homodimeric enzyme that protects cells from oxidative damage. Hereditary and sporadic amyotrophic lateral sclerosis may be linked to SOD1 when the enzyme is destabilized through mutation or environmental stress. The cytotoxicity of demetallated or apo-SOD1 aggregates may be due to their ability to cause defects within cell membranes by co-aggregating with phospholipids. SOD1 monomers may associate with the inner cell membrane to receive copper ions from membrane-bound copper chaperones. But how apo-SOD1 interacts with lipids is unclear. We have used atomistic molecular dynamics simulations to reveal that flexible electrostatic and zinc-binding loops in apo-SOD1 dimers play a critical role in the binding of 1-octanol clusters and phospholipid bilayer, without any significant unfolding of the protein. The apo-SOD1 monomer also associates with phospholipid bilayer via its zinc-binding loop rather than its exposed hydrophobic dimerization interface. Our observed orientation of the monomer on the bilayer would facilitate its association with a membrane-bound copper chaperone. The orientation also suggests how membrane-bound monomers could act as seeds for membrane-associated SOD1 aggregation.
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Affiliation(s)
- Choon-Peng Chng
- Biophysical Modeling Group, Bioinformatics Institute, A*STAR (Agency for Science, Technology and Research), Singapore, 138671, Republic of Singapore
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31
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Prabhu S, Dennison SR, Mura M, Lea RW, Snape TJ, Harris F. Cn
-AMP2 from green coconut water is an anionic anticancer peptide. J Pept Sci 2014; 20:909-15. [DOI: 10.1002/psc.2684] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2014] [Revised: 07/07/2014] [Accepted: 07/27/2014] [Indexed: 12/30/2022]
Affiliation(s)
- Saurabh Prabhu
- School of Pharmacy and Biomedical Sciences; University of Central Lancashire; Preston PR1 2HE UK
| | - Sarah R. Dennison
- School of Pharmacy and Biomedical Sciences; University of Central Lancashire; Preston PR1 2HE UK
| | - Manuela Mura
- School of Computing Engineering and Physical Science; University of Central Lancashire; Preston PR1 2HE UK
| | - Robert W. Lea
- School of Pharmacy and Biomedical Sciences; University of Central Lancashire; Preston PR1 2HE UK
| | - Timothy J. Snape
- School of Pharmacy and Biomedical Sciences; University of Central Lancashire; Preston PR1 2HE UK
| | - Frederick Harris
- School of Forensic and Investigative Science; University of Central Lancashire; Preston PR1 2HE UK
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32
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Interactions of peripheral proteins with model membranes as viewed by molecular dynamics simulations. Biochem Soc Trans 2014; 42:1418-24. [DOI: 10.1042/bst20140144] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Many cellular signalling and related events are triggered by the association of peripheral proteins with anionic lipids in the cell membrane (e.g. phosphatidylinositol phosphates or PIPs). This association frequently occurs via lipid-binding modules, e.g. pleckstrin homology (PH), C2 and four-point-one, ezrin, radixin, moesin (FERM) domains, present in peripheral and cytosolic proteins. Multiscale simulation approaches that combine coarse-grained and atomistic MD simulations may now be applied with confidence to investigate the molecular mechanisms of the association of peripheral proteins with model bilayers. Comparisons with experimental data indicate that such simulations can predict specific peripheral protein–lipid interactions. We discuss the application of multiscale MD simulation and related approaches to investigate the association of peripheral proteins which contain PH, C2 or FERM-binding modules with lipid bilayers of differing phospholipid composition, including bilayers containing multiple PIP molecules.
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33
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Two homologous neutrophil serine proteases bind to POPC vesicles with different affinities: When aromatic amino acids matter. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1838:3191-202. [PMID: 25218402 DOI: 10.1016/j.bbamem.2014.09.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Revised: 08/29/2014] [Accepted: 09/03/2014] [Indexed: 11/22/2022]
Abstract
Neutrophil serine proteases Proteinase 3 (PR3) and human neutrophil elastase (HNE) are homologous antibiotic serine proteases of the polymorphonuclear neutrophils. Despite sharing a 56% sequence identity they have been shown to have different functions and localizations in the neutrophils. In particular, and in contrast to HNE, PR3 has been detected at the outer leaflet of the plasma membrane and its membrane expression is a risk factor in a number of chronic inflammatory diseases. Although a plethora of studies performed in various cell-based assays have been reported, the mechanism by which PR3, and possibly HNE bind to simple membrane models remains unclear. We used surface plasmon resonance (SPR) experiments to measure and compare the affinity of PR3 and HNE for large unilamellar vesicles composed of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC). We also conducted 500-nanosecond long molecular dynamics simulations of each enzyme at the surface of a POPC bilayer to map the interactions between proteins and lipids and rationalize the difference in affinity observed in the SPR experiment. We find that PR3 binds strongly to POPC large unilamellar vesicles (Kd=9.2×10(-7)M) thanks to the insertion of three phenylalanines, one tryptophan and one leucine beyond the phosphate groups of the POPC lipids. HNE binds in a significantly weaker manner (Kd>10(-5)M) making mostly electrostatic interactions via lysines and arginines and inserting only one leucine between the hydrophobic lipid tails. Our results support the early reports that PR3, unlike HNE, is able to directly and strongly anchor directly to the neutrophil membrane.
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34
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Fuller JC, Martinez M, Wade RC. On calculation of the electrostatic potential of a phosphatidylinositol phosphate-containing phosphatidylcholine lipid membrane accounting for membrane dynamics. PLoS One 2014; 9:e104778. [PMID: 25141217 PMCID: PMC4139306 DOI: 10.1371/journal.pone.0104778] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Accepted: 07/16/2014] [Indexed: 12/21/2022] Open
Abstract
Many signaling events require the binding of cytoplasmic proteins to cell membranes by recognition of specific charged lipids, such as phosphoinositol-phosphates. As a model for a protein-membrane binding site, we consider one charged phosphoinositol phosphate (PtdIns(3)P) embedded in a phosphatidylcholine bilayer. As the protein-membrane binding is driven by electrostatic interactions, continuum solvent models require an accurate representation of the electrostatic potential of the phosphoinositol phosphate-containing membrane. We computed and analyzed the electrostatic potentials of snapshots taken at regular intervals from molecular dynamics simulations of the bilayer. We observe considerable variation in the electrostatic potential of the bilayer both along a single simulation and between simulations performed with the GAFF or CHARMM c36 force fields. However, we find that the choice of GAFF or CHARMM c36 parameters has little effect on the electrostatic potential of a given configuration of the bilayer with a PtdIns(3)P embedded in it. From our results, we propose a remedian averaging method for calculating the electrostatic potential of a membrane system that is suitable for simulations of protein-membrane binding with a continuum solvent model.
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Affiliation(s)
- Jonathan C. Fuller
- Molecular and Cellular Modeling Group, Heidelberg Institute for Theoretical Studies, Heidelberg, Germany
| | - Michael Martinez
- Molecular and Cellular Modeling Group, Heidelberg Institute for Theoretical Studies, Heidelberg, Germany
| | - Rebecca C. Wade
- Molecular and Cellular Modeling Group, Heidelberg Institute for Theoretical Studies, Heidelberg, Germany
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany
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35
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Kalli AC, Devaney I, Sansom MSP. Interactions of phosphatase and tensin homologue (PTEN) proteins with phosphatidylinositol phosphates: insights from molecular dynamics simulations of PTEN and voltage sensitive phosphatase. Biochemistry 2014; 53:1724-32. [PMID: 24588644 PMCID: PMC4167384 DOI: 10.1021/bi5000299] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
![]()
The
phosphatase and tensin homologue (PTEN) and the Ciona
intestinalis voltage sensitive phosphatase (Ci-VSP) are both
phosphatidylinositol phosphate (PIP) phosphatases that contain a C2
domain. PTEN is a tumor suppressor protein that acts as a phosphatase
on PIP3 in mammalian cell membranes. It contains two principal
domains:
a phosphatase domain (PD) and a C2 domain. Despite detailed structural
and functional characterization, less is known about its mechanism
of interaction with PIP-containing lipid bilayers. Ci-VSP consists
of an N-terminal transmembrane voltage sensor domain and a C-terminal
PTEN domain, which in turn contains a PD and a C2 domain. The nature
of the interaction of the PTEN domain of Ci-VSP with membranes has
not been well established. We have used multiscale molecular dynamics
simulations to define the interaction mechanisms
of PTEN and of the Ci-VSP PTEN domains with PIP-containing lipid bilayers.
Our results suggest a novel mechanism of association of the PTEN with
such bilayers, in which an initial electrostatics-driven encounter
of the protein and bilayer is followed by reorientation of the protein
to optimize its interactions with PIP molecules in the membrane. Although
a PIP3 molecule binds close to the active site of PTEN,
our simulations suggest a further conformational change of the protein
may be required for catalytically productive binding to occur. Ci-VSP
interacted with membranes in an orientation comparable to that of
PTEN but bound directly to PIP-containing membranes without a subsequent
reorientation step. Again, PIP3 bound close to the active
site of the Ci-VSP PD, but not in a catalytically productive manner.
Interactions of Ci-VSP with the bilayer induced clustering of PIP
molecules around the protein.
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Affiliation(s)
- Antreas C Kalli
- Department of Biochemistry, University of Oxford , South Parks Road, Oxford OX1 3QU, U.K
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36
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Del Campo CM, Mishra AK, Wang YH, Roy CR, Janmey PA, Lambright DG. Structural basis for PI(4)P-specific membrane recruitment of the Legionella pneumophila effector DrrA/SidM. Structure 2014; 22:397-408. [PMID: 24530282 DOI: 10.1016/j.str.2013.12.018] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Revised: 11/19/2013] [Accepted: 12/10/2013] [Indexed: 01/09/2023]
Abstract
Recruitment of the Legionella pneumophila effector DrrA to the Legionella-containing vacuole, where it activates and AMPylates Rab1, is mediated by a P4M domain that binds phosphatidylinositol 4-phosphate [PI(4)P] with high affinity and specificity. Despite the importance of PI(4)P in Golgi trafficking and its manipulation by pathogens, the structural bases for PI(4)P-dependent membrane recruitment remain poorly defined. Here, we determined the crystal structure of a DrrA fragment including the P4M domain in complex with dibutyl PI(4)P and investigated the determinants of phosphoinositide recognition and membrane targeting. Headgroup recognition involves an elaborate network of direct and water-mediated interactions with basic and polar residues in the context of a deep, constrictive binding pocket. An adjacent hydrophobic helical element packs against the acyl chains and inserts robustly into PI(4)P-containing monolayers. The structural, biochemical, and biophysical data reported here support a detailed structural mechanism for PI(4)P-dependent membrane targeting by DrrA.
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Affiliation(s)
- Claudia M Del Campo
- Program in Molecular Medicine and Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Ashwini K Mishra
- Program in Molecular Medicine and Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Yu-Hsiu Wang
- Institute for Medicine and Engineering and Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Craig R Roy
- Department of Microbial Pathogenesis, Yale University School of Medicine, Boyer Center for Molecular Medicine, New Haven, CT 06536, USA
| | - Paul A Janmey
- Institute for Medicine and Engineering and Department of Physiology, Perelman School of Medicine, University of Pennsylvania, PA 19104, USA
| | - David G Lambright
- Program in Molecular Medicine and Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA.
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37
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Kalli AC, Morgan G, Sansom MSP. Interactions of the auxilin-1 PTEN-like domain with model membranes result in nanoclustering of phosphatidyl inositol phosphates. Biophys J 2014; 105:137-45. [PMID: 23823232 DOI: 10.1016/j.bpj.2013.05.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Revised: 05/06/2013] [Accepted: 05/07/2013] [Indexed: 11/18/2022] Open
Abstract
Auxilin-1 is a neuron-specific membrane-binding protein involved in a late stage of clathrin-mediated endocytosis. It recruits Hsc70, thus initiating uncoating of the clathrin-coated vesicles. Interactions of auxilin-1 with the vesicle membrane are crucial for this function and are mediated via an N-terminal PTEN-like domain. We have used multiscale molecular dynamics simulations to probe the interactions of the auxilin-1 PTEN-like domain with lipid bilayers containing differing phospholipid composition, including bilayers containing phosphatidyl inositol phosphates. Our results suggest a novel, to our knowledge, model for the auxilin/membrane encounter and subsequent interactions. Negatively charged lipids (especially PIP2) enhance binding of auxilin to lipid bilayers and facilitate its correct orientation relative to the membrane. Mutations in three basic residues (R301E/R307E/K311E) of the C2 subdomain of the PTEN-like domain perturbed its interaction with the bilayer, changing its orientation. The interaction of membrane-bound auxilin-1 PTEN-like domain with negatively charged lipid headgroups results in nanoclustering of PIP2 molecules in the adjacent bilayer leaflet.
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Affiliation(s)
- Antreas C Kalli
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
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38
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Pleskot R, Pejchar P, Staiger CJ, Potocký M. When fat is not bad: the regulation of actin dynamics by phospholipid signaling molecules. FRONTIERS IN PLANT SCIENCE 2014; 5:5. [PMID: 24478785 PMCID: PMC3899574 DOI: 10.3389/fpls.2014.00005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Accepted: 01/04/2014] [Indexed: 05/21/2023]
Abstract
The actin cytoskeleton plays a key role in the plant morphogenesis and is involved in polar cell growth, movement of subcellular organelles, cell division, and plant defense. Organization of actin cytoskeleton undergoes dynamic remodeling in response to internal developmental cues and diverse environmental signals. This dynamic behavior is regulated by numerous actin-binding proteins (ABPs) that integrate various signaling pathways. Production of the signaling lipids phosphatidylinositol 4,5-bisphosphate and phosphatidic acid affects the activity and subcellular distribution of several ABPs, and typically correlates with increased actin polymerization. Here we review current knowledge of the inter-regulatory dynamics between signaling phospholipids and the actin cytoskeleton in plant cells.
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Affiliation(s)
- Roman Pleskot
- Institute of Experimental Botany, v. v. i., Academy of Sciences of the Czech RepublicPrague, Czech Republic
| | - Přemysl Pejchar
- Institute of Experimental Botany, v. v. i., Academy of Sciences of the Czech RepublicPrague, Czech Republic
| | | | - Martin Potocký
- Institute of Experimental Botany, v. v. i., Academy of Sciences of the Czech RepublicPrague, Czech Republic
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39
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Kalli AC, Campbell ID, Sansom MSP. Conformational changes in talin on binding to anionic phospholipid membranes facilitate signaling by integrin transmembrane helices. PLoS Comput Biol 2013; 9:e1003316. [PMID: 24204243 PMCID: PMC3814715 DOI: 10.1371/journal.pcbi.1003316] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2013] [Accepted: 09/19/2013] [Indexed: 01/01/2023] Open
Abstract
Integrins are heterodimeric (αβ) cell surface receptors that are activated to a high affinity state by the formation of a complex involving the α/β integrin transmembrane helix dimer, the head domain of talin (a cytoplasmic protein that links integrins to actin), and the membrane. The talin head domain contains four sub-domains (F0, F1, F2 and F3) with a long cationic loop inserted in the F1 domain. Here, we model the binding and interactions of the complete talin head domain with a phospholipid bilayer, using multiscale molecular dynamics simulations. The role of the inserted F1 loop, which is missing from the crystal structure of the talin head, PDB:3IVF, is explored. The results show that the talin head domain binds to the membrane predominantly via cationic regions on the F2 and F3 subdomains and the F1 loop. Upon binding, the intact talin head adopts a novel V-shaped conformation which optimizes its interactions with the membrane. Simulations of the complex of talin with the integrin α/β TM helix dimer in a membrane, show how this complex promotes a rearrangement, and eventual dissociation of, the integrin α and β transmembrane helices. A model for the talin-mediated integrin activation is proposed which describes how the mutual interplay of interactions between transmembrane helices, the cytoplasmic talin protein, and the lipid bilayer promotes integrin inside-out activation. Transmission of signals across the cell membrane is an essential process for all living organisms. Integrins are one example of cell surface receptors (αβ) which, uniquely, form a bidirectional signalling pathway across the membrane. Integrins are crucial for many cellular processes and play key roles in pathological defects such as cardiovascular diseases and cancer. They are activated to a high affinity state by the intracellular protein talin in a process known as ‘inside-out activation’. Despite their importance and the existence of functional and structural data, the mechanism by which talin activates integrin remains elusive. In this study we use a multi-scale computational approach, which combines coarse-grained and atomistic molecular dynamics simulations, to suggest how the formation of the complex between the talin head domain, the cell membrane and the integrin moves the integrin equilibrium towards an active state. Our results show that conformational changes within the talin head domains optimize its interactions with the cell membrane. Upon binding to the integrin, talin facilitates rearrangement of the integrin TM region thus promoting integrin activation. This study also provides a demonstration of the strengths of a computational multi-scale approach in studies of membrane interactions and receptor conformational changes and associated proteins that enable transmembrane signaling.
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Affiliation(s)
- Antreas C. Kalli
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Iain D. Campbell
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Mark S. P. Sansom
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
- * E-mail:
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40
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Structural basis for membrane recruitment and allosteric activation of cytohesin family Arf GTPase exchange factors. Proc Natl Acad Sci U S A 2013; 110:14213-8. [PMID: 23940353 PMCID: PMC3761562 DOI: 10.1073/pnas.1301883110] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Membrane recruitment of cytohesin family Arf guanine nucleotide exchange factors depends on interactions with phosphoinositides and active Arf GTPases that, in turn, relieve autoinhibition of the catalytic Sec7 domain through an unknown structural mechanism. Here, we show that Arf6-GTP relieves autoinhibition by binding to an allosteric site that includes the autoinhibitory elements in addition to the PH domain. The crystal structure of a cytohesin-3 construct encompassing the allosteric site in complex with the head group of phosphatidyl inositol 3,4,5-trisphosphate and N-terminally truncated Arf6-GTP reveals a large conformational rearrangement, whereby autoinhibition can be relieved by competitive sequestration of the autoinhibitory elements in grooves at the Arf6/PH domain interface. Disposition of the known membrane targeting determinants on a common surface is compatible with multivalent membrane docking and subsequent activation of Arf substrates, suggesting a plausible model through which membrane recruitment and allosteric activation could be structurally integrated.
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Dennison SR, Harris F, Mura M, Morton LHG, Zvelindovsky A, Phoenix DA. A novel form of bacterial resistance to the action of eukaryotic host defense peptides, the use of a lipid receptor. Biochemistry 2013; 52:6021-9. [PMID: 23895279 DOI: 10.1021/bi400719j] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Host defense peptides show great potential for development as new antimicrobial agents with novel mechanisms of action. However, a small number of resistance mechanisms to their action are known, and here, we report a novel bacterial resistance mechanism mediated by a lipid receptor. Maximin H5 from Bombina maxima bound anionic and zwitterionic membranes with low affinity (Kd > 225 μM) while showing a strong ability to lyse (>55%) and penetrate (π > 6.0 mN m(-1)) these membranes. However, the peptide bound Escherichia coli and 1,2-dimyristoyl-sn-glycero-3-phosphoethanolamine (DMPE) membranes with higher affinity (Kd < 65 μM) and showed a very low ability for bilayer lysis (<8%) and partitioning (π > 1.0 mN m(-1)). Increasing levels of membrane DMPE correlated with enhanced binding by the peptide (R(2) = 0.96) but inversely correlated with its lytic ability (R(2) = 0.98). Taken with molecular dynamic simulations, these results suggest that maximin H5 possesses membranolytic activity, primarily involving bilayer insertion of its strongly hydrophobic N-terminal region. However, this region was predicted to form multiple hydrogen bonds with phosphate and ammonium groups within PE head-groups, which in concert with charge-charge interactions anchor the peptide to the surface of E. coli membranes, inhibiting its membranolytic action.
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Affiliation(s)
- Sarah R Dennison
- School of Pharmacy and Biomedical Sciences, †School of Forensic and Investigative Sciences, and ‡School of Computing, Engineering and Physical Sciences, University of Central Lancashire , Preston, PR1 2HE, U.K
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Lumb CN, Sansom MSP. Defining the membrane-associated state of the PTEN tumor suppressor protein. Biophys J 2013; 104:613-21. [PMID: 23442912 DOI: 10.1016/j.bpj.2012.12.002] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Revised: 11/28/2012] [Accepted: 12/04/2012] [Indexed: 11/19/2022] Open
Abstract
Phosphatase and tensin-homolog deleted on chromosome 10 (PTEN) is a tumor-suppressor protein that regulates phosphatidylinositol 3-kinase (PI3-K) signaling by binding to the plasma membrane and hydrolyzing the 3' phosphate from phosphatidylinositol (3,4,5)-trisphosphate (PI(3,4,5)P3) to form phosphatidylinositol (4,5)-bisphosphate (PI(4,5)P2). Several loss-of-function mutations in PTEN that impair lipid phosphatase activity and membrane binding are oncogenic, leading to the development of a variety of cancers, but information about the membrane-associated state of PTEN remains sparse. We have modeled a membrane-associated state of the truncated PTEN structure bound to PI(3,4,5)P3 via multiscale molecular dynamics simulations. We show that the location of the membrane-binding surface agrees with experimental observations and is robust to changes in lipid composition. The level of membrane interaction is substantially reduced in the phosphatase domain for the triple mutant R161E/K163E/K164E, in line with experimental results. We observe clustering of anionic lipids around the C2 domain in preference to the phosphatase domain, suggesting that the C2 domain is involved in nonspecific interactions with negatively charged lipid headgroups. Finally, our simulations suggest that the oncogenicity of the R335L mutation may be due to a reduction in the interaction of the mutant PTEN with anionic lipids.
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Affiliation(s)
- Craig N Lumb
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
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Lai CL, Srivastava A, Pilling C, Chase AR, Falke JJ, Voth GA. Molecular mechanism of membrane binding of the GRP1 PH domain. J Mol Biol 2013; 425:3073-90. [PMID: 23747485 DOI: 10.1016/j.jmb.2013.05.026] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Revised: 05/28/2013] [Accepted: 05/29/2013] [Indexed: 10/26/2022]
Abstract
The pleckstrin homology (PH) domain of the general receptor of phosphoinositides 1 (GRP1) protein selectively binds to a rare signaling phospholipid, phosphatidylinositol (3,4,5)-trisphosphate (PIP3), in the membrane. The specific PIP3 lipid docking of GRP1 PH domain is essential to protein cellular function and is believed to occur in a stepwise process, electrostatic-driven membrane association followed by the specific PIP3 binding. By a combination of all-atom molecular dynamics (MD) simulations, coarse-grained analysis, electron paramagnetic resonance (EPR) membrane docking geometry, and fluorescence resonance energy transfer (FRET) kinetic studies, we have investigated the search and bind process in the GRP1 PH domain at the molecular scale. We simulated the two membrane binding states of the GRP1 PH domain in the PIP3 search process, before and after the GRP1 PH domain docks with the PIP3 lipid. Our results suggest that the background anionic phosphatidylserine lipids, which constitute around one-fifth of the membrane by composition, play a critical role in the initial stages of recruiting protein to the membrane surface through non-specific electrostatic interactions. Our data also reveal a previously unseen transient membrane association mechanism that is proposed to enable a two-dimensional "hopping" search of the membrane surface for the rare PIP3 target lipid. We further modeled the PIP3-bound membrane-protein system using the EPR membrane docking structure for the MD simulations, quantitatively validating the EPR membrane docking structure and augmenting our understanding of the binding interface with atomic-level detail. Several observations and hypotheses reached from our MD simulations are also supported by experimental kinetic studies.
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Affiliation(s)
- Chun-Liang Lai
- Department of Chemistry, Institute of Biophysical Dynamics, James Franck Institute, and Computation Institute, University of Chicago, Chicago, IL 60637, USA
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Membrane-Binding Mechanism of a Peripheral Membrane Protein through Microsecond Molecular Dynamics Simulations. J Mol Biol 2012; 423:847-61. [DOI: 10.1016/j.jmb.2012.08.015] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Revised: 08/16/2012] [Accepted: 08/20/2012] [Indexed: 11/22/2022]
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Finding a needle in a haystack: the role of electrostatics in target lipid recognition by PH domains. PLoS Comput Biol 2012; 8:e1002617. [PMID: 22844242 PMCID: PMC3406000 DOI: 10.1371/journal.pcbi.1002617] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2012] [Accepted: 06/01/2012] [Indexed: 11/19/2022] Open
Abstract
Interactions between protein domains and lipid molecules play key roles in controlling cell membrane signalling and trafficking. The pleckstrin homology (PH) domain is one of the most widespread, binding specifically to phosphatidylinositol phosphates (PIPs) in cell membranes. PH domains must locate specific PIPs in the presence of a background of approximately 20% anionic lipids within the cytoplasmic leaflet of the plasma membrane. We investigate the mechanism of such recognition via a multiscale procedure combining Brownian dynamics (BD) and molecular dynamics (MD) simulations of the GRP1 PH domain interacting with phosphatidylinositol (3,4,5)-trisphosphate (PI(3,4,5)P3). The interaction of GRP1-PH with PI(3,4,5)P3 in a zwitterionic bilayer is compared with the interaction in bilayers containing different levels of anionic ‘decoy’ lipids. BD simulations reveal both translational and orientational electrostatic steering of the PH domain towards the PI(3,4,5)P3-containing anionic bilayer surface. There is a payoff between non-PIP anionic lipids attracting the PH domain to the bilayer surface in a favourable orientation and their role as ‘decoys’, disrupting the interaction of GRP1-PH with the PI(3,4,5)P3 molecule. Significantly, approximately 20% anionic lipid in the cytoplasmic leaflet of the bilayer is nearly optimal to both enhance orientational steering and to localise GRP1-PH proximal to the surface of the membrane without sacrificing its ability to locate PI(3,4,5)P3 within the bilayer plane. Subsequent MD simulations reveal binding to PI(3,4,5)P3, forming protein-phosphate contacts comparable to those in X-ray structures. These studies demonstrate a computational framework which addresses lipid recognition within a cell membrane environment, offering a link between structural and cell biological characterisation. Cell signalling pathways are crucial for many biological processes including cell proliferation and survival. Signalling is governed by a complex network of interactions within the cell, and disruption of signalling can lead to a variety of human diseases. Often, a key event in the signalling cascade is the reversible recruitment of peripheral membrane proteins to the surface of the cell membrane, where they then bind to a specific lipid in order to perform their function. However, it is not clear how these proteins locate their target lipid in the complex multi-lipid environment of the plasma membrane. Here, we have used a combination of computational techniques to simulate the association of a signalling protein with the surface of the cell membrane. We demonstrate that the mechanism of membrane binding is dependent upon the lipid composition of the lipid bilayer, and the results show that orientational and positional steering of the protein is optimised when the anionic lipid content of our model membrane matches the physiological composition observed in cells.
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Chen HC, Ziemba BP, Landgraf KE, Corbin JA, Falke JJ. Membrane docking geometry of GRP1 PH domain bound to a target lipid bilayer: an EPR site-directed spin-labeling and relaxation study. PLoS One 2012; 7:e33640. [PMID: 22479423 PMCID: PMC3316598 DOI: 10.1371/journal.pone.0033640] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2011] [Accepted: 02/14/2012] [Indexed: 11/18/2022] Open
Abstract
The second messenger lipid PIP3 (phosphatidylinositol-3,4,5-trisphosphate) is generated by the lipid kinase PI3K (phosphoinositide-3-kinase) in the inner leaflet of the plasma membrane, where it regulates a broad array of cell processes by recruiting multiple signaling proteins containing PIP3-specific pleckstrin homology (PH) domains to the membrane surface. Despite the broad importance of PIP3-specific PH domains, the membrane docking geometry of a PH domain bound to its target PIP3 lipid on a bilayer surface has not yet been experimentally determined. The present study employs EPR site-directed spin labeling and relaxation methods to elucidate the membrane docking geometry of GRP1 PH domain bound to bilayer-embedded PIP3. The model target bilayer contains the neutral background lipid PC and both essential targeting lipids: (i) PIP3 target lipid that provides specificity and affinity, and (ii) PS facilitator lipid that enhances the PIP3 on-rate via an electrostatic search mechanism. The EPR approach measures membrane depth parameters for 18 function-retaining spin labels coupled to the PH domain, and for calibration spin labels coupled to phospholipids. The resulting depth parameters, together with the known high resolution structure of the co-complex between GRP1 PH domain and the PIP3 headgroup, provide sufficient constraints to define an optimized, self-consistent membrane docking geometry. In this optimized geometry the PH domain engulfs the PIP3 headgroup with minimal bilayer penetration, yielding the shallowest membrane position yet described for a lipid binding domain. This binding interaction displaces the PIP3 headgroup from its lowest energy position and orientation in the bilayer, but the headgroup remains within its energetically accessible depth and angular ranges. Finally, the optimized docking geometry explains previous biophysical findings including mutations observed to disrupt membrane binding, and the rapid lateral diffusion observed for PIP3-bound GRP1 PH domain on supported lipid bilayers.
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Affiliation(s)
| | | | | | | | - Joseph J. Falke
- Department of Chemistry and Biochemistry and the Molecular Biophysics Program, University of Colorado, Boulder, Colorado, United States of America
- * E-mail:
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Scott JL, Musselman CA, Adu-Gyamfi E, Kutateladze TG, Stahelin RV. Emerging methodologies to investigate lipid-protein interactions. Integr Biol (Camb) 2012; 4:247-58. [PMID: 22327461 DOI: 10.1039/c2ib00143h] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Cellular membranes are composed of hundreds of different lipids, ion channels, receptors and scaffolding complexes that act as signalling and trafficking platforms for processes fundamental to life. Cellular signalling and membrane trafficking are often regulated by peripheral proteins, which reversibly interact with lipid molecules in highly regulated spatial and temporal fashions. In most cases, one or more modular lipid-binding domain(s) mediate recruitment of peripheral proteins to specific cellular membranes. These domains, of which more than 10 have been identified since 1989, harbour structurally selective lipid-binding sites. Traditional in vitro and in vivo studies have elucidated how these domains coordinate their cognate lipids and thus how the parent proteins associate with membranes. Cellular activities of peripheral proteins and subsequent physiological processes depend upon lipid binding affinities and selectivity. Thus, the development of novel sensitive and quantitative tools is essential in furthering our understanding of the function and regulation of these proteins. As this field expands into new areas such as computational biology, cellular lipid mapping, single molecule imaging, and lipidomics, there is an urgent need to integrate technologies to detail the molecular architecture and mechanisms of lipid signalling. This review surveys emerging cellular and in vitro approaches for studying protein-lipid interactions and provides perspective on how integration of methodologies directs the future development of the field.
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Affiliation(s)
- Jordan L Scott
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA
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Abstract
Diverse biological processes including cell growth and survival require transient association of proteins with cellular membranes. A large number of these proteins are drawn to a bilayer through binding of their modular domains to phosphoinositide (PI) lipids. Seven PI isoforms are found to concentrate in distinct pools of intracellular membranes, and this lipid compartmentalization provides an efficient way for recruiting PI-binding proteins to specific cellular organelles. The atomic-resolution structures and membrane docking mechanisms of a dozen PI effectors have been elucidated in the last decade, offering insight into the molecular basis for regulation of the PI-dependent signaling pathways. In this chapter, I summarize the mechanistic aspects of deciphering the 'PI code' by the most common PI-recognizing domains and discuss similarities and differences in the membrane anchoring mechanisms.
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Affiliation(s)
- Tatiana G Kutateladze
- Department of Pharmacology, University of Colorado Denver School of Medicine, Aurora, CO 80045, USA.
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Stansfeld P, Sansom M. Molecular Simulation Approaches to Membrane Proteins. Structure 2011; 19:1562-72. [DOI: 10.1016/j.str.2011.10.002] [Citation(s) in RCA: 132] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2011] [Revised: 09/29/2011] [Accepted: 10/03/2011] [Indexed: 11/17/2022]
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