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Bian C, Marchetti A, Dias M, Perrin J, Cosson P. Short transmembrane domains target type II proteins to the Golgi apparatus and type I proteins to the endoplasmic reticulum. J Cell Sci 2024; 137:jcs261738. [PMID: 38973735 DOI: 10.1242/jcs.261738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Accepted: 06/18/2024] [Indexed: 07/09/2024] Open
Abstract
Transmembrane domains (TMDs) contain information targeting membrane proteins to various compartments of the secretory pathway. In previous studies, short or hydrophilic TMDs have been shown to target membrane proteins either to the endoplasmic reticulum (ER) or to the Golgi apparatus. However, the basis for differential sorting to the ER and to the Golgi apparatus remained unclear. To clarify this point, we quantitatively analyzed the intracellular targeting of a collection of proteins exhibiting a single TMD. Our results reveal that membrane topology is a major targeting element in the early secretory pathway: type I proteins with a short TMD are targeted to the ER, and type II proteins to the Golgi apparatus. A combination of three features accounts for the sorting of simple membrane proteins in the secretory pathway: membrane topology, length and hydrophilicity of the TMD, and size of the cytosolic domain. By clarifying the rules governing sorting to the ER and to the Golgi apparatus, our study could revive the search for sorting mechanisms in the early secretory pathway.
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Affiliation(s)
- Claudie Bian
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, 1 Rue Michel Servet, 1211 Geneva 4, Switzerland
- Manufacturing Science and Technologies, Biotech Department, Merck, Z.I. de l'Ouriettaz 150, 1170 Aubonne, Switzerland
| | - Anna Marchetti
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, 1 Rue Michel Servet, 1211 Geneva 4, Switzerland
| | - Marco Dias
- Manufacturing Science and Technologies, Biotech Department, Merck, Z.I. de l'Ouriettaz 150, 1170 Aubonne, Switzerland
| | - Jackie Perrin
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, 1 Rue Michel Servet, 1211 Geneva 4, Switzerland
| | - Pierre Cosson
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, 1 Rue Michel Servet, 1211 Geneva 4, Switzerland
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2
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Blazhynska M, Gumbart JC, Chen H, Tajkhorshid E, Roux B, Chipot C. A Rigorous Framework for Calculating Protein-Protein Binding Affinities in Membranes. J Chem Theory Comput 2023; 19:9077-9092. [PMID: 38091976 PMCID: PMC11145395 DOI: 10.1021/acs.jctc.3c00941] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2023]
Abstract
Calculating the binding free energy of integral transmembrane (TM) proteins is crucial for understanding the mechanisms by which they recognize one another and reversibly associate. The glycophorin A (GpA) homodimer, composed of two α-helical segments, has long served as a model system for studying TM protein reversible association. The present work establishes a methodological framework for calculating the binding affinity of the GpA homodimer in the heterogeneous environment of a membrane. Our investigation carefully considered a variety of protocols, including the appropriate choice of the force field, rigorous standardization reflecting the experimental conditions, sampling algorithm, anisotropic environment, and collective variables, to accurately describe GpA dimerization via molecular dynamics-based approaches. Specifically, two strategies were explored: (i) an unrestrained potential mean force (PMF) calculation, which merely enhances sampling along the separation of the two binding partners without any restraint, and (ii) a so-called "geometrical route", whereby the α-helices are progressively separated with imposed restraints on their orientational, positional, and conformational degrees of freedom to accelerate convergence. Our simulations reveal that the simplified, unrestrained PMF approach is inadequate for the description of GpA dimerization. Instead, the geometrical route, tailored specifically to GpA in a membrane environment, yields excellent agreement with experimental data within a reasonable computational time. A dimerization free energy of -10.7 kcal/mol is obtained, in fairly good agreement with available experimental data. The geometrical route further helps elucidate how environmental forces drive association before helical interactions stabilize it. Our simulations also brought to light a distinct, long-lived spatial arrangement that potentially serves as an intermediate state during dimer formation. The methodological advances in the generalized geometrical route provide a powerful tool for accurate and efficient binding-affinity calculations of intricate TM protein complexes in inhomogeneous environments.
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Affiliation(s)
- Marharyta Blazhynska
- Laboratoire International Associé Centre National de la Recherche Scientifique et University of Illinois at Urbana-Champaign, Unité Mixte de Recherche n°7019, Université de Lorraine, B.P. 70239, Vandœuvre-lès-Nancy cedex 54506, France
| | - James C Gumbart
- School of Physics, Georgia Institute of Technology, 837 State Street, Atlanta, Georgia 30332, United States
| | - Haochuan Chen
- Laboratoire International Associé Centre National de la Recherche Scientifique et University of Illinois at Urbana-Champaign, Unité Mixte de Recherche n°7019, Université de Lorraine, B.P. 70239, Vandœuvre-lès-Nancy cedex 54506, France
| | - Emad Tajkhorshid
- Theoretical and Computational Biophysics Group, NIH Center for Macromolecular Modeling and Visualization, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, 405 N. Mathews Avenue, Urbana, Illinois 61801, United States
- Department of Biochemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, Illinois 61801, United States
| | - Benoît Roux
- Department of Biochemistry and Molecular Biology, The University of Chicago, 929 E. 57th Street W225, Chicago, Illinois 60637, United States
- Department of Chemistry, The University of Chicago, 5735 S. Ellis Avenue, Chicago, Illinois 60637, United States
| | - Christophe Chipot
- Laboratoire International Associé Centre National de la Recherche Scientifique et University of Illinois at Urbana-Champaign, Unité Mixte de Recherche n°7019, Université de Lorraine, B.P. 70239, Vandœuvre-lès-Nancy cedex 54506, France
- Theoretical and Computational Biophysics Group, NIH Center for Macromolecular Modeling and Visualization, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, 405 N. Mathews Avenue, Urbana, Illinois 61801, United States
- Department of Biochemistry and Molecular Biology, The University of Chicago, 929 E. 57th Street W225, Chicago, Illinois 60637, United States
- Department of Chemistry, The University of Hawai'i at Ma̅noa, 2545 McCarthy Mall, Honolulu, Hawaii 96822, United States
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3
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Has C, Das SL. The Functionality of Membrane-Inserting Proteins and Peptides: Curvature Sensing, Generation, and Pore Formation. J Membr Biol 2023; 256:343-372. [PMID: 37650909 DOI: 10.1007/s00232-023-00289-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 08/04/2023] [Indexed: 09/01/2023]
Abstract
Proteins and peptides with hydrophobic and amphiphilic segments are responsible for many biological functions. The sensing and generation of membrane curvature are the functions of several protein domains or motifs. While some specific membrane proteins play an essential role in controlling the curvature of distinct intracellular membranes, others participate in various cellular processes such as clathrin-mediated endocytosis, where several proteins sort themselves at the neck of the membrane bud. A few membrane-inserting proteins form nanopores that permeate selective ions and water to cross the membrane. In addition, many natural and synthetic small peptides and protein toxins disrupt the membrane by inducing nonspecific pores in the membrane. The pore formation causes cell death through the uncontrolled exchange between interior and exterior cellular contents. In this article, we discuss the insertion depth and orientation of protein/peptide helices, and their role as a sensor and inducer of membrane curvature as well as a pore former in the membrane. We anticipate that this extensive review will assist biophysicists to gain insight into curvature sensing, generation, and pore formation by membrane insertion.
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Affiliation(s)
- Chandra Has
- Department of Chemical Engineering, GSFC University, Vadodara, 391750, Gujarat, India.
| | - Sovan Lal Das
- Physical and Chemical Biology Laboratory and Department of Mechanical Engineering, Indian Institute of Technology, Palakkad, 678623, Kerala, India
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Yamamoto R, Segawa R, Liu J, Isaji T, Gu J, Hiratsuka M, Hirasawa N. Effect of N-glycosylation on constitutive signal transduction by mutated cytokine receptor-like factor 2. Biochim Biophys Acta Gen Subj 2023; 1867:130465. [PMID: 37748663 DOI: 10.1016/j.bbagen.2023.130465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 09/06/2023] [Accepted: 09/11/2023] [Indexed: 09/27/2023]
Abstract
BACKGROUND Cytokine receptor-like factor 2 (CRLF2) is a subunit of the receptor for thymic stromal lymphopoietin (TSLP). A somatic mutation (insEIM) in the transmembrane domains of CRLF2 has been identified in acute lymphocytic leukemia (ALL), and Glu-Ile-Met (EIM) CRLF2 induces constitutive activation of signals. However, the signaling mechanism remains unclear. METHODS HEK293 cells were transfected with expression vectors encoding wild-type (WT), insEIM CRLF2, or their mutants which N-glycosylation site was replaced with a glutamine. Cell surface expression of CRLF2 was assessed by flow cytometry. Total CRLF2 and phosphorylated signal transducer and activator of transcription 5 (STAT5) were detected by western blotting. RESULTS Three major species of CRLF2 (53-, 57- and 58-kDa) were identified. Deglycosylation analysis revealed that they were modified with complex-type and oligomannose-type glycans. The expression of both WT and EIM CRLF2 decreased in N-acetylglucosaminyltransferase (GnT)-I (MGAT1) knockout (KO) cells and slightly decreased in α1,6-fucosyltransferase (Fut8) KO cells compared to that in the control cells. In GnT-I or Fut8 KO cells, WT CRLF2 did not induce ligand-independent activation. Both WT and EIM CRLF2 contained four N-glycosylation sites. N55 of CRLF2 was required for the cell surface expression and activation by EIM CRLF2. CONCLUSIONS We found that N-glycosylation of CRLF2 plays crucial roles for its cell surface expression and signaling. However, N-glycan processing in the Golgi apparatus does not seem to be essential for ligand-independent activation of EIM CRLF2. GENERAL SIGNIFICANCE Our studies provide a crucial role of glycosylation in the cell surface expression of receptors.
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Affiliation(s)
- Rio Yamamoto
- Laboratory of Pharmacotherapy of Life-Style Related Diseases, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Miyagi, Japan
| | - Ryosuke Segawa
- Laboratory of Pharmacotherapy of Life-Style Related Diseases, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Miyagi, Japan
| | - Jianwei Liu
- Division of Regulatory Glycobiology, Institute of Molecular Biomembrane and Glycobiology, Tohoku Medical and Pharmaceutical University, Sendai 981-8558, Japan
| | - Tomoya Isaji
- Division of Regulatory Glycobiology, Institute of Molecular Biomembrane and Glycobiology, Tohoku Medical and Pharmaceutical University, Sendai 981-8558, Japan
| | - Jianguo Gu
- Division of Regulatory Glycobiology, Institute of Molecular Biomembrane and Glycobiology, Tohoku Medical and Pharmaceutical University, Sendai 981-8558, Japan
| | - Masahiro Hiratsuka
- Laboratory of Pharmacotherapy of Life-Style Related Diseases, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Miyagi, Japan
| | - Noriyasu Hirasawa
- Laboratory of Pharmacotherapy of Life-Style Related Diseases, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Miyagi, Japan.
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5
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Necelis M, McDermott C, Belcher Dufrisne M, Baryiames C, Columbus L. Solution NMR investigations of integral membrane proteins: Challenges and innovations. Curr Opin Struct Biol 2023; 82:102654. [PMID: 37542910 PMCID: PMC10529709 DOI: 10.1016/j.sbi.2023.102654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 05/08/2023] [Accepted: 06/20/2023] [Indexed: 08/07/2023]
Abstract
Compared to soluble protein counterparts, the understanding of membrane protein stability, solvent interactions, and function are not as well understood. Recent advancements in labeling, expression, and stabilization of membrane proteins have enabled solution nuclear magnetic resonance spectroscopy to investigate membrane protein conformational states, ligand binding, lipid interactions, stability, and folding. This review highlights these advancements and new understandings and provides examples of recent applications.
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Affiliation(s)
- Matthew Necelis
- Department of Chemistry, University of Virginia, Charlottesville, VA, USA
| | - Connor McDermott
- Department of Chemistry, University of Virginia, Charlottesville, VA, USA
| | | | | | - Linda Columbus
- Department of Chemistry, University of Virginia, Charlottesville, VA, USA.
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6
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Rangel K, Lechuga GC, Provance DW, Morel CM, De Simone SG. An Update on the Therapeutic Potential of Antimicrobial Peptides against Acinetobacter baumannii Infections. Pharmaceuticals (Basel) 2023; 16:1281. [PMID: 37765087 PMCID: PMC10537560 DOI: 10.3390/ph16091281] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2023] [Revised: 08/09/2023] [Accepted: 09/06/2023] [Indexed: 09/29/2023] Open
Abstract
The rise in antibiotic-resistant strains of clinically important pathogens is a major threat to global health. The World Health Organization (WHO) has recognized the urgent need to develop alternative treatments to address the growing list of priority pathogens. Antimicrobial peptides (AMPs) rank among the suggested options with proven activity and high potential to be developed into effective drugs. Many AMPs are naturally produced by living organisms protecting the host against pathogens as a part of their innate immunity. Mechanisms associated with AMP actions include cell membrane disruption, cell wall weakening, protein synthesis inhibition, and interference in nucleic acid dynamics, inducing apoptosis and necrosis. Acinetobacter baumannii is a critical pathogen, as severe clinical implications have developed from isolates resistant to current antibiotic treatments and conventional control procedures, such as UV light, disinfectants, and drying. Here, we review the natural AMPs representing primary candidates for new anti-A. baumannii drugs in post-antibiotic-era and present computational tools to develop the next generation of AMPs with greater microbicidal activity and reduced toxicity.
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Affiliation(s)
- Karyne Rangel
- Center for Technological Development in Health (CDTS), National Institute of Science and Technology for Innovation in Neglected Population Diseases (INCT-IDPN), Oswaldo Cruz Institut, Oswaldo Cruz Foundation, Rio de Janeiro 21040-900, RJ, Brazil; (K.R.); (G.C.L.); (D.W.P.J.); (C.M.M.)
- Epidemiology and Molecular Systematics Laboratory (LEMS), Oswaldo Cruz Institut, Oswaldo Cruz Foundation, Rio de Janeiro 21040-900, RJ, Brazil
| | - Guilherme Curty Lechuga
- Center for Technological Development in Health (CDTS), National Institute of Science and Technology for Innovation in Neglected Population Diseases (INCT-IDPN), Oswaldo Cruz Institut, Oswaldo Cruz Foundation, Rio de Janeiro 21040-900, RJ, Brazil; (K.R.); (G.C.L.); (D.W.P.J.); (C.M.M.)
- Epidemiology and Molecular Systematics Laboratory (LEMS), Oswaldo Cruz Institut, Oswaldo Cruz Foundation, Rio de Janeiro 21040-900, RJ, Brazil
| | - David W. Provance
- Center for Technological Development in Health (CDTS), National Institute of Science and Technology for Innovation in Neglected Population Diseases (INCT-IDPN), Oswaldo Cruz Institut, Oswaldo Cruz Foundation, Rio de Janeiro 21040-900, RJ, Brazil; (K.R.); (G.C.L.); (D.W.P.J.); (C.M.M.)
- Epidemiology and Molecular Systematics Laboratory (LEMS), Oswaldo Cruz Institut, Oswaldo Cruz Foundation, Rio de Janeiro 21040-900, RJ, Brazil
| | - Carlos M. Morel
- Center for Technological Development in Health (CDTS), National Institute of Science and Technology for Innovation in Neglected Population Diseases (INCT-IDPN), Oswaldo Cruz Institut, Oswaldo Cruz Foundation, Rio de Janeiro 21040-900, RJ, Brazil; (K.R.); (G.C.L.); (D.W.P.J.); (C.M.M.)
| | - Salvatore G. De Simone
- Center for Technological Development in Health (CDTS), National Institute of Science and Technology for Innovation in Neglected Population Diseases (INCT-IDPN), Oswaldo Cruz Institut, Oswaldo Cruz Foundation, Rio de Janeiro 21040-900, RJ, Brazil; (K.R.); (G.C.L.); (D.W.P.J.); (C.M.M.)
- Epidemiology and Molecular Systematics Laboratory (LEMS), Oswaldo Cruz Institut, Oswaldo Cruz Foundation, Rio de Janeiro 21040-900, RJ, Brazil
- Program of Post-Graduation on Science and Biotechnology, Department of Molecular and Cellular Biology, Biology Institute, Federal Fluminense University, Niterói 22040-036, RJ, Brazil
- Program of Post-Graduation on Parasitic Biology, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro 21040-900, RJ, Brazil
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Yano Y, Morise T, Matsuzaki K. Effects of Gly Residue and Cholesterol on the GXXXG-Mediated Parallel Association of Transmembrane Helices: A Single-Pair FRET Study. Chembiochem 2022; 23:e202200160. [PMID: 36229427 DOI: 10.1002/cbic.202200160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Revised: 10/12/2022] [Indexed: 01/25/2023]
Abstract
Small residue-mediated interhelical packing is ubiquitous in helical membrane proteins: however, the lipid dependence of its stability remains unclear. We previously demonstrated that the introduction of a GXXXG sequence in the middle of de novo-designed (AALALAA)3 helices (AALALAA AGLALGA AALALAA) facilitated their dimerization, which was abolished by cholesterol. Here single-pair FRET measurements revealed that a longer GXXXGXXXG segment (AALALAA A GLALGA AAGALAA) promoted helix dimerization in POPC/cholesterol bilayers, but not without cholesterol. The predicted dimer structures and degrees of helix packing suggested that helix dimers with small (∼10°) and large (∼55°) crossing angles were only stabilized in POPC and POPC/cholesterol membranes, respectively. A steric hindrance in the dimer interface and the large flexibility of helices prevented the formation of stable dimers. Therefore, amino acid sequences and lipid compositions distinctively constrain stable dimer structures in membranes.
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Affiliation(s)
- Yoshiaki Yano
- School of Pharmacy and Pharmaceutical Sciences, Mukogawa Woman's University, Nishinomiya, 663-8179, Japan
| | - Takayuki Morise
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, 606-8501, Japan
| | - Katsumi Matsuzaki
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, 606-8501, Japan
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Hellmann N, Schneider D. Hydrophobic mismatch and sequence specificity compete when transmembrane helix-helix interactions are measured with the TOXCAT assay. Front Chem 2022; 10:1049310. [DOI: 10.3389/fchem.2022.1049310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 11/16/2022] [Indexed: 11/29/2022] Open
Abstract
Genetic assays capable of measuring the propensity of transmembrane helices to oligomerize within the cytoplasmic membrane of the bacterium E. coli are frequently used when sequence-specificity in transmembrane helix-helix interactions is investigated. In the present study, dimerization of the well-investigated wild-type and G83I-mutated transmembrane helix of the human glycophorin A protein was studied. Gradual prolongation of the transmembrane helix at the C-terminus with Leu residues lead to pronounced changes in the dimerization propensity when measured with the TOXCAT assay. Thus, besides sequence specificity, hydrophobic mismatch between the hydrophobic core of a studied transmembrane helix and the E. coli membrane can impact the oligomerization propensity of a transmembrane helix. This suggests that the results of genetic assays aiming at determining interactions of heterologous transmembrane helices within the E. coli membrane do not necessarily solely reflect sequence specificity in transmembrane helix-helix interactions, but might be additionally modulated by topological and structural effects caused by hydrophobic mismatch.
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Yano Y. Effects of Membrane Cholesterol on Stability of Transmembrane Helix Associations. Chem Pharm Bull (Tokyo) 2022; 70:514-518. [DOI: 10.1248/cpb.c22-00144] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Yoshiaki Yano
- School of Pharmacy and Pharmaceutical Sciences, Mukogawa Woman’s University
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McGuire H, Blunck R. Studying KcsA Channel Clustering Using Single Channel Voltage-Clamp Fluorescence Imaging*. Front Physiol 2022; 13:863375. [PMID: 35721536 PMCID: PMC9204084 DOI: 10.3389/fphys.2022.863375] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 05/16/2022] [Indexed: 11/13/2022] Open
Abstract
Oligomerization and complex formation play a key role for many membrane proteins and has been described to influence ion channel function in both neurons and the heart. In this study, we observed clustering of single KcsA channels in planar lipid bilayer using single molecule fluorescence, while simultaneously measuring single channel currents. Clustering coincided with cooperative opening of KcsA. We demonstrate that clustering was not caused by direct protein-protein interactions or hydrophobic mismatch with the lipid environment, as suggested earlier, but was mediated via microdomains induced by the channel in the lipid matrix. We found that single channel activity of KcsA requires conically-shaped lipids in the lamellar liquid-crystalline (Lα) phase, and the need for a negative spontaneous curvature seem to lead to the deformations in the membrane that cause the clustering. The method introduced here will be applicable to follow oligomerization of a wide range of membrane proteins.
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Affiliation(s)
- Hugo McGuire
- Department of Physics, Université de Montréal, Montréal, QC, Canada
| | - Rikard Blunck
- Department of Physics, Université de Montréal, Montréal, QC, Canada
- Department of Pharmacology and Physiology, Université de Montréal, Montréal, QC, Canada
- Interdisciplinary Research Center on Brain and Learning (CIRCA), Université de Montréal, Montréal, QC, Canada
- *Correspondence: Rikard Blunck,
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11
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Alavizargar A, Elting A, Wedlich-Söldner R, Heuer A. Lipid-Mediated Association of the Slg1 Transmembrane Domains in Yeast Plasma Membranes. J Phys Chem B 2022; 126:3240-3256. [PMID: 35446028 DOI: 10.1021/acs.jpcb.2c00192] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Clustering of transmembrane proteins underlies a multitude of fundamental biological processes at the plasma membrane (PM) such as receptor activation, lateral domain formation, and mechanotransduction. The self-association of the respective transmembrane domains (TMDs) has also been suggested to be responsible for the micron-scaled patterns seen for integral membrane proteins in the budding yeast PM. However, the underlying interplay between the local lipid composition and the TMD identity is still not mechanistically understood. In this work, we combined coarse-grained molecular dynamics simulations of simplified bilayer systems with high-resolution live-cell microscopy to analyze the distribution of a representative helical yeast TMD from the PM sensor Slg1 within different lipid environments. In our simulations, we specifically evaluated the effects of acyl chain saturation and anionic lipid head groups on the association of two TMDs. We found that weak lipid-protein interactions significantly affect the configuration of TMD dimers and the free energy of association. Increased amounts of unsaturated phospholipids (PLs) strongly reduced the helix-helix interaction, while the presence of anionic phosphatidylserine (PS) hardly affected the dimer formation. We could experimentally confirm this surprising lack of effect of PS using the network factor, a mesoscopic measure of PM pattern formation in yeast cells. Simulations also showed that the formation of TMD dimers in turn increased the order parameter of the surrounding lipids and induced long-range perturbations in lipid organization. In summary, our results shed new light on the mechanisms of lipid-mediated dimerization of TMDs in complex lipid mixtures.
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Affiliation(s)
- Azadeh Alavizargar
- Institute of Physical Chemistry, University of Muenster, Corrensstr. 28/30, 48149 Muenster, Germany
| | - Annegret Elting
- Institute of Cell Dynamics and Imaging, University of Muenster, Von-Esmarch-Str. 56, 48149 Muenster, Germany
| | - Roland Wedlich-Söldner
- Institute of Cell Dynamics and Imaging, University of Muenster, Von-Esmarch-Str. 56, 48149 Muenster, Germany
| | - Andreas Heuer
- Institute of Physical Chemistry, University of Muenster, Corrensstr. 28/30, 48149 Muenster, Germany
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Potent Activity of Hybrid Arthropod Antimicrobial Peptides Linked by Glycine Spacers. Int J Mol Sci 2021; 22:ijms22168919. [PMID: 34445625 PMCID: PMC8396199 DOI: 10.3390/ijms22168919] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 08/05/2021] [Accepted: 08/15/2021] [Indexed: 11/22/2022] Open
Abstract
Arthropod antimicrobial peptides (AMPs) offer a promising source of new leads to address the declining number of novel antibiotics and the increasing prevalence of multidrug-resistant bacterial pathogens. AMPs with potent activity against Gram-negative bacteria and distinct modes of action have been identified in insects and scorpions, allowing the discovery of AMP combinations with additive and/or synergistic effects. Here, we tested the synergistic activity of two AMPs, from the dung beetle Copris tripartitus (CopA3) and the scorpion Heterometrus petersii (Hp1090), against two strains of Escherichia coli. We also tested the antibacterial activity of two hybrid peptides generated by joining CopA3 and Hp1090 with linkers comprising two (InSco2) or six (InSco6) glycine residues. We found that CopA3 and Hp1090 acted synergistically against both bacterial strains, and the hybrid peptide InSco2 showed more potent bactericidal activity than the parental AMPs or InSco6. Molecular dynamics simulations revealed that the short linker stabilizes an N-terminal 310-helix in the hybrid peptide InSco2. This secondary structure forms from a coil region that interacts with phosphatidylethanolamine in the membrane bilayer model. The highest concentration of the hybrid peptides used in this study was associated with stronger hemolytic activity than equivalent concentrations of the parental AMPs. As observed for CopA3, the increasing concentration of InSco2 was also cytotoxic to BHK-21 cells. We conclude that AMP hybrids linked by glycine spacers display potent antibacterial activity and that the cytotoxic activity can be modulated by adjusting the nature of the linker peptide, thus offering a strategy to produce hybrid peptides as safe replacements or adjuncts for conventional antibiotic therapy.
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13
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Chadda R, Bernhardt N, Kelley EG, Teixeira SC, Griffith K, Gil-Ley A, Öztürk TN, Hughes LE, Forsythe A, Krishnamani V, Faraldo-Gómez JD, Robertson JL. Membrane transporter dimerization driven by differential lipid solvation energetics of dissociated and associated states. eLife 2021; 10:63288. [PMID: 33825681 PMCID: PMC8116059 DOI: 10.7554/elife.63288] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Accepted: 04/06/2021] [Indexed: 12/22/2022] Open
Abstract
Over two-thirds of integral membrane proteins of known structure assemble into oligomers. Yet, the forces that drive the association of these proteins remain to be delineated, as the lipid bilayer is a solvent environment that is both structurally and chemically complex. In this study, we reveal how the lipid solvent defines the dimerization equilibrium of the CLC-ec1 Cl-/H+ antiporter. Integrating experimental and computational approaches, we show that monomers associate to avoid a thinned-membrane defect formed by hydrophobic mismatch at their exposed dimerization interfaces. In this defect, lipids are strongly tilted and less densely packed than in the bulk, with a larger degree of entanglement between opposing leaflets and greater water penetration into the bilayer interior. Dimerization restores the membrane to a near-native state and therefore, appears to be driven by the larger free-energy cost of lipid solvation of the dissociated protomers. Supporting this theory, we demonstrate that addition of short-chain lipids strongly shifts the dimerization equilibrium toward the monomeric state, and show that the cause of this effect is that these lipids preferentially solvate the defect. Importantly, we show that this shift requires only minimal quantities of short-chain lipids, with no measurable impact on either the macroscopic physical state of the membrane or the protein's biological function. Based on these observations, we posit that free-energy differentials for local lipid solvation define membrane-protein association equilibria. With this, we argue that preferential lipid solvation is a plausible cellular mechanism for lipid regulation of oligomerization processes, as it can occur at low concentrations and does not require global changes in membrane properties. A cell’s outer membrane is made of molecules called lipids, which band together to form a flexible thin film, just two molecules thick. This membrane is dotted with proteins that transport materials in to and out of cells. Most of these membrane proteins join with other proteins to form structures known as oligomers. Except, how membrane-bound proteins assemble into oligomers – the physical forces driving these molecules to take shape – remains unclear. This is partly because the structural, physical and chemical properties of fat-like lipid membranes are radically different to the cell’s watery interior. Consequently, the conditions under which membrane oligomers form are distinct from those surrounding proteins inside cells. Membrane proteins are also more difficult to study and characterize than water-soluble proteins inside the cell, and yet many therapeutic drugs such as antibiotics specifically target membrane proteins. Overall, our understanding of how the unique properties of lipid membranes affect the formation of protein structures embedded within, is lacking and warrants further investigation. Now, Chadda, Bernhardt et al. focused on one membrane protein, known as CLC, which tends to exist in pairs – or dimers. To understand why these proteins form dimers (a process called dimerization) Chadda, Bernhardt et al. first used computer simulations, and then validated the findings in experimental tests. These complementary approaches demonstrated that the main reason CLC proteins ‘dimerize’ lies in their interaction with the lipid membrane, and not the attraction of one protein to its partner. When CLC proteins are on their own, they deform the surrounding membrane and create structural defects that put the membrane under strain. But when two CLC proteins join as a dimer, this membrane strain disappears – making dimerization the more stable and energetically favorable option. Chadda, Bernhardt et al. also showed that with the addition of a few certain lipids, specifically smaller lipids, cell membranes become more tolerant of protein-induced structural changes. This might explain how cells could use various lipids to fine-tune the activity of membrane proteins by controlling how oligomers form. However, the theory needs to be examined further. Altogether, this work has provided fundamental insights into the physical forces shaping membrane-bound proteins, relevant to researchers studying cell biology and pharmacology alike.
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Affiliation(s)
- Rahul Chadda
- Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, United States
| | - Nathan Bernhardt
- Theoretical Molecular Biophysics Laboratory, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, United States
| | - Elizabeth G Kelley
- NIST Center for Neutron Research, National Institute for Standards and Technology, Gaithersburg, United States
| | - Susana Cm Teixeira
- NIST Center for Neutron Research, National Institute for Standards and Technology, Gaithersburg, United States.,Center for Neutron Science, Chemical and Biomolecular Engineering, University of Delaware, Newark, United States
| | - Kacie Griffith
- Molecular Physiology and Biophysics, Carver College of Medicine, The University of Iowa, Iowa City, United States
| | - Alejandro Gil-Ley
- Theoretical Molecular Biophysics Laboratory, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, United States.,Molecular Physiology and Biophysics, Carver College of Medicine, The University of Iowa, Iowa City, United States
| | - Tuğba N Öztürk
- Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, United States
| | - Lauren E Hughes
- Molecular Physiology and Biophysics, Carver College of Medicine, The University of Iowa, Iowa City, United States
| | - Ana Forsythe
- Molecular Physiology and Biophysics, Carver College of Medicine, The University of Iowa, Iowa City, United States
| | - Venkatramanan Krishnamani
- Molecular Physiology and Biophysics, Carver College of Medicine, The University of Iowa, Iowa City, United States
| | - José D Faraldo-Gómez
- Theoretical Molecular Biophysics Laboratory, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, United States
| | - Janice L Robertson
- Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, United States
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14
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Souza PCT, Alessandri R, Barnoud J, Thallmair S, Faustino I, Grünewald F, Patmanidis I, Abdizadeh H, Bruininks BMH, Wassenaar TA, Kroon PC, Melcr J, Nieto V, Corradi V, Khan HM, Domański J, Javanainen M, Martinez-Seara H, Reuter N, Best RB, Vattulainen I, Monticelli L, Periole X, Tieleman DP, de Vries AH, Marrink SJ. Martini 3: a general purpose force field for coarse-grained molecular dynamics. Nat Methods 2021; 18:382-388. [PMID: 33782607 DOI: 10.1038/s41592-021-01098-3] [Citation(s) in RCA: 466] [Impact Index Per Article: 155.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 02/22/2021] [Indexed: 01/31/2023]
Abstract
The coarse-grained Martini force field is widely used in biomolecular simulations. Here we present the refined model, Martini 3 ( http://cgmartini.nl ), with an improved interaction balance, new bead types and expanded ability to include specific interactions representing, for example, hydrogen bonding and electronic polarizability. The updated model allows more accurate predictions of molecular packing and interactions in general, which is exemplified with a vast and diverse set of applications, ranging from oil/water partitioning and miscibility data to complex molecular systems, involving protein-protein and protein-lipid interactions and material science applications as ionic liquids and aedamers.
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Affiliation(s)
- Paulo C T Souza
- Groningen Biomolecular Sciences and Biotechnology Institute and Zernike Institute for Advanced Material, University of Groningen, Groningen, the Netherlands. .,Molecular Microbiology and Structural Biochemistry, UMR 5086 CNRS and University of Lyon, Lyon, France.
| | - Riccardo Alessandri
- Groningen Biomolecular Sciences and Biotechnology Institute and Zernike Institute for Advanced Material, University of Groningen, Groningen, the Netherlands
| | - Jonathan Barnoud
- Groningen Biomolecular Sciences and Biotechnology Institute and Zernike Institute for Advanced Material, University of Groningen, Groningen, the Netherlands.,Intangible Realities Laboratory, University of Bristol, School of Chemistry, Bristol, UK
| | - Sebastian Thallmair
- Groningen Biomolecular Sciences and Biotechnology Institute and Zernike Institute for Advanced Material, University of Groningen, Groningen, the Netherlands.,Frankfurt Institute for Advanced Studies, Frankfurt am Main, Germany
| | - Ignacio Faustino
- Groningen Biomolecular Sciences and Biotechnology Institute and Zernike Institute for Advanced Material, University of Groningen, Groningen, the Netherlands
| | - Fabian Grünewald
- Groningen Biomolecular Sciences and Biotechnology Institute and Zernike Institute for Advanced Material, University of Groningen, Groningen, the Netherlands
| | - Ilias Patmanidis
- Groningen Biomolecular Sciences and Biotechnology Institute and Zernike Institute for Advanced Material, University of Groningen, Groningen, the Netherlands
| | - Haleh Abdizadeh
- Groningen Biomolecular Sciences and Biotechnology Institute and Zernike Institute for Advanced Material, University of Groningen, Groningen, the Netherlands
| | - Bart M H Bruininks
- Groningen Biomolecular Sciences and Biotechnology Institute and Zernike Institute for Advanced Material, University of Groningen, Groningen, the Netherlands
| | - Tsjerk A Wassenaar
- Groningen Biomolecular Sciences and Biotechnology Institute and Zernike Institute for Advanced Material, University of Groningen, Groningen, the Netherlands
| | - Peter C Kroon
- Groningen Biomolecular Sciences and Biotechnology Institute and Zernike Institute for Advanced Material, University of Groningen, Groningen, the Netherlands
| | - Josef Melcr
- Groningen Biomolecular Sciences and Biotechnology Institute and Zernike Institute for Advanced Material, University of Groningen, Groningen, the Netherlands
| | - Vincent Nieto
- Molecular Microbiology and Structural Biochemistry, UMR 5086 CNRS and University of Lyon, Lyon, France
| | - Valentina Corradi
- Centre for Molecular Simulation and Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
| | - Hanif M Khan
- Centre for Molecular Simulation and Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada.,Department of Chemistry and Computational Biology Unit, University of Bergen, Bergen, Norway
| | - Jan Domański
- Department of Biochemistry, University of Oxford, Oxford, UK.,Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Matti Javanainen
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Prague, Czech Republic.,Computational Physics Laboratory, Tampere University, Tampere, Finland
| | - Hector Martinez-Seara
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Prague, Czech Republic
| | - Nathalie Reuter
- Department of Chemistry and Computational Biology Unit, University of Bergen, Bergen, Norway
| | - Robert B Best
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Ilpo Vattulainen
- Computational Physics Laboratory, Tampere University, Tampere, Finland.,Department of Physics, University of Helsinki, Helsinki, Finland
| | - Luca Monticelli
- Molecular Microbiology and Structural Biochemistry, UMR 5086 CNRS and University of Lyon, Lyon, France
| | - Xavier Periole
- Department of Chemistry, Aarhus University, Aarhus C, Denmark
| | - D Peter Tieleman
- Centre for Molecular Simulation and Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
| | - Alex H de Vries
- Groningen Biomolecular Sciences and Biotechnology Institute and Zernike Institute for Advanced Material, University of Groningen, Groningen, the Netherlands
| | - Siewert J Marrink
- Groningen Biomolecular Sciences and Biotechnology Institute and Zernike Institute for Advanced Material, University of Groningen, Groningen, the Netherlands.
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15
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Yano Y, Watanabe Y, Matsuzaki K. Thermodynamic and kinetic stabilities of transmembrane helix bundles as revealed by single-pair FRET analysis: Effects of the number of membrane-spanning segments and cholesterol. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1863:183532. [PMID: 33316240 DOI: 10.1016/j.bbamem.2020.183532] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 12/02/2020] [Accepted: 12/07/2020] [Indexed: 12/23/2022]
Abstract
The tertiary structures and conformational dynamics of transmembrane (TM) helical proteins are maintained by the interhelical interaction network in membranes, although it is complicated to analyze the underlying driving forces because the amino acid sequences can involve multiple and various types of interactions. To obtain insights into basal and common effects of the number of membrane-spanning segments and membrane cholesterol, we measured stabilities of helix bundles composed of simple TM helices (AALALAA)3 (1TM) and (AALALAA)3-G5-(AALALAA)3 (2TM). Association-dissociation dynamics for 1TM-1TM, 1TM-2TM, and 2TM-2TM pairs were monitored to compare stabilities of 2-, 3-, and 4-helical bundles, respectively, with single-pair fluorescence resonance energy transfer (sp-FRET) in liposome membranes. Both thermodynamic and kinetic stabilities of the helix bundles increased with a greater number of membrane-spanning segments in POPC. The presence of 30 mol% cholesterol strongly enhanced the formation of 1TM-1TM and 1TM-2TM bundles (~ - 9 kJ mol-1), whereas it only weakly stabilized the 2TM-2TM bundle (~ - 3 kJ mol-1). Fourier transform infrared-polarized attenuated total reflection (ATR-FTIR) spectroscopy revealed an ~30° tilt of the helix axis relative to bilayer normal for the 1TM-2TM pair in the presence of cholesterol, suggesting the formation of a tilted helix bundle to release high lateral pressure at the center of cholesterol-containing membranes. These results demonstrate that the number of membrane-spanning segments affects the stability and structure of the helix bundle, and their cholesterol-dependences. Such information is useful to understand the basics of folding and assembly of multispanning TM proteins.
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Affiliation(s)
- Yoshiaki Yano
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Yuta Watanabe
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Katsumi Matsuzaki
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan.
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16
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Radyukhin VA, Baratova LA. Molecular Mechanisms of Raft Organization in Biological Membranes. RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2020. [DOI: 10.1134/s1068162020030164] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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17
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Gopal SM, Pawar AB, Wassenaar TA, Sengupta D. Lipid-dependent conformational landscape of the ErbB2 growth factor receptor dimers. Chem Phys Lipids 2020; 230:104911. [PMID: 32353357 DOI: 10.1016/j.chemphyslip.2020.104911] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 03/04/2020] [Accepted: 03/27/2020] [Indexed: 01/31/2023]
Abstract
Altered lipid metabolism has been linked to cancer development and progression. Several roles have been attributed to the increased saturation and length of lipid acyl tails observed in tumors, but its effect on signaling receptors is still emerging. In this work, we have analyzed the lipid dependence of the ErbB2 growth factor receptor dimerization that plays an important role in the pathogenesis of breast cancer. We have performed coarse-grain ensemble molecular dynamics simulations to comprehensively sample the ErbB2 monomer-dimer association. Our results indicate a dynamic dimer state with a complex conformational landscape that is modulated with increasing lipid tail length. We resolve the native N-terminal "active" and C-terminal "inactive" conformations in all membrane compositions. However, the relative population of the N-terminal and C-terminal conformers is dependent on length of the saturated lipid tails. In short-tail membranes, additional non-specific dimers are observed which are reduced or absent in long-tailed bilayers. Our results indicate that the relative population as well as the structure of the dimer state is modulated by membrane composition. We have correlated these differences to local perturbations of the membrane around the receptor. Our work is an important step in characterizing ErbB dimers in healthy and diseased states and emphasize the importance of sampling lipid dynamics in understanding receptor association.
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Affiliation(s)
- Srinivasa M Gopal
- CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411 008, India; Lehrstuhl fur Theoretische Chemie, Ruhr University Bochum, D-44780 Bochum, Germany
| | - Aiswarya B Pawar
- CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411 008, India; AcSIR, Mathura Road, New Delhi, 110 025, India
| | - Tsjerk A Wassenaar
- Molecular Dynamics, University of Groningen, Nijenborgh 7, 9747AG Groningen, the Netherlands
| | - Durba Sengupta
- CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411 008, India; AcSIR, Mathura Road, New Delhi, 110 025, India.
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18
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Transmembrane Domain Dissociation Is Required for Hendra Virus F Protein Fusogenic Activity. J Virol 2019; 93:JVI.01069-19. [PMID: 31462574 DOI: 10.1128/jvi.01069-19] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Accepted: 08/19/2019] [Indexed: 12/12/2022] Open
Abstract
Hendra virus (HeV) is a zoonotic paramyxovirus that utilizes a trimeric fusion (F) protein within its lipid bilayer to mediate membrane merger with a cell membrane for entry. Previous HeV F studies showed that transmembrane domain (TMD) interactions are important for stabilizing the prefusion conformation of the protein prior to triggering. Thus, the current model for HeV F fusion suggests that modulation of TMD interactions is critical for initiation and completion of conformational changes that drive membrane fusion. HeV F constructs (T483C/V484C, V484C/N485C, and N485C/P486C) were generated with double cysteine substitutions near the N-terminal region of the TMD to study the effect of altered flexibility in this region. Oligomeric analysis showed that the double cysteine substitutions successfully promoted intersubunit disulfide bond formation in HeV F. Subsequent fusion assays indicated that the introduction of disulfide bonds in the mutants prohibited fusion events. Further testing confirmed that T483C/V484C and V484C/N485C were expressed at the cell surface at levels that would allow for fusion. Attempts to restore fusion with a reducing agent were unsuccessful, suggesting that the introduced disulfide bonds were likely buried in the membrane. Conformational analysis showed that T483C/V484C and V484C/N485C were able to bind a prefusion conformation-specific antibody prior to cell disruption, indicating that the introduced disulfide bonds did not significantly affect protein folding. This study is the first to report that TMD dissociation is required for HeV F fusogenic activity and strengthens our model for HeV fusion.IMPORTANCE The paramyxovirus Hendra virus (HeV) causes severe respiratory illness and encephalitis in humans. To develop therapeutics for HeV and related viral infections, further studies are needed to understand the mechanisms underlying paramyxovirus fusion events. Knowledge gained in studies of the HeV fusion (F) protein may be applicable to a broad span of enveloped viruses. In this study, we demonstrate that disulfide bonds introduced between the HeV F transmembrane domains (TMDs) block fusion. Depending on the location of these disulfide bonds, HeV F can still fold properly and bind a prefusion conformation-specific antibody prior to cell disruption. These findings support our current model for HeV membrane fusion and expand our knowledge of the TMD and its role in HeV F stability and fusion promotion.
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19
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Hydrophobic matching of HIV-1 Vpu transmembrane helix-helix interactions is optimized for subcellular location. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2019; 1861:183022. [PMID: 31302078 DOI: 10.1016/j.bbamem.2019.07.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2019] [Revised: 06/06/2019] [Accepted: 07/09/2019] [Indexed: 11/21/2022]
Abstract
The HIV-1 accessory protein Vpu mediates the downregulation of several host cell proteins, an activity that is critical for viral replication in vivo. As the first step in directing cell-surface proteins to internal cellular compartments, and in many cases degradation, Vpu binds a subset of its target proteins through their transmembrane domains. Each of the known targets of Vpu are synthesized in the ER, and must traverse the different membrane environments found along the secretory pathway, thus it is important to consider how membrane composition might influence the interactions between Vpu and its targets. We have used Förster resonance energy transfer (FRET) to measure the oligomerization of Vpu with the transmembrane domains of target proteins in model membranes of varying lipid composition. Our data show that both lipid bilayer thickness and acyl chain order can significantly influence monomer-oligomer equilibria within the Vpu-target system. Changes in oligomerization levels were found to be non-specific with no single Vpu-target interaction being favored under any condition. Our analysis of the influence of the membrane environment on the strength of helix-helix interactions between Vpu and its targets in vitro suggests that the strength of Vpu-target interactions in vivo will be partially dependent on the membrane environment found in specific membrane compartments.
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20
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Olšinová M, Jurkiewicz P, Kishko I, Sýkora J, Sabó J, Hof M, Cwiklik L, Cebecauer M. Roughness of Transmembrane Helices Reduces Lipid Membrane Dynamics. iScience 2018; 10:87-97. [PMID: 30508721 PMCID: PMC6277224 DOI: 10.1016/j.isci.2018.11.026] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 10/23/2018] [Accepted: 11/14/2018] [Indexed: 01/23/2023] Open
Abstract
The dynamics of cellular membranes is primarily determined by lipid species forming a bilayer. Proteins are considered mainly as effector molecules of diverse cellular processes. In addition to large assemblies of proteins, which were found to influence properties of fluid membranes, biological membranes are densely populated by small, highly mobile proteins. However, little is known about the effect of such proteins on the dynamics of membranes. Using synthetic peptides, we demonstrate that transmembrane helices interfere with the mobility of membrane components by trapping lipid acyl chains on their rough surfaces. The effect is more pronounced in the presence of cholesterol, which segregates from the rough surface of helical peptides. This may contribute to the formation or stabilization of membrane heterogeneities. Since roughness is a general property of helical transmembrane segments, our results suggest that, independent of their size or cytoskeleton linkage, integral membrane proteins affect local membrane dynamics and organization.
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Affiliation(s)
- Marie Olšinová
- Department of Biophysical Chemistry, J. Heyrovsky Institute of Physical Chemistry of the Czech Academy of Sciences, Dolejškova 3, 182 23 Prague, Czech Republic
| | - Piotr Jurkiewicz
- Department of Biophysical Chemistry, J. Heyrovsky Institute of Physical Chemistry of the Czech Academy of Sciences, Dolejškova 3, 182 23 Prague, Czech Republic
| | - Iryna Kishko
- Department of Biophysical Chemistry, J. Heyrovsky Institute of Physical Chemistry of the Czech Academy of Sciences, Dolejškova 3, 182 23 Prague, Czech Republic
| | - Jan Sýkora
- Department of Biophysical Chemistry, J. Heyrovsky Institute of Physical Chemistry of the Czech Academy of Sciences, Dolejškova 3, 182 23 Prague, Czech Republic
| | - Ján Sabó
- Department of Biophysical Chemistry, J. Heyrovsky Institute of Physical Chemistry of the Czech Academy of Sciences, Dolejškova 3, 182 23 Prague, Czech Republic
| | - Martin Hof
- Department of Biophysical Chemistry, J. Heyrovsky Institute of Physical Chemistry of the Czech Academy of Sciences, Dolejškova 3, 182 23 Prague, Czech Republic
| | - Lukasz Cwiklik
- Department of Theoretical Chemistry, J. Heyrovsky Institute of Physical Chemistry of the Czech Academy of Sciences, Dolejškova 3, 182 23 Prague, Czech Republic
| | - Marek Cebecauer
- Department of Biophysical Chemistry, J. Heyrovsky Institute of Physical Chemistry of the Czech Academy of Sciences, Dolejškova 3, 182 23 Prague, Czech Republic.
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21
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Bragin PE, Kuznetsov AS, Bocharova OV, Volynsky PE, Arseniev AS, Efremov RG, Mineev KS. Probing the effect of membrane contents on transmembrane protein-protein interaction using solution NMR and computer simulations. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:2486-2498. [PMID: 30279150 DOI: 10.1016/j.bbamem.2018.09.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Revised: 09/03/2018] [Accepted: 09/17/2018] [Indexed: 12/18/2022]
Abstract
The interaction between the secondary structure elements is the key process, determining the spatial structure and activity of a membrane protein. Transmembrane (TM) helix-helix interaction is known to be especially important for the function of so-called type I or bitopic membrane proteins. In the present work, we present the approach to study the helix-helix interaction in the TM domains of membrane proteins in various lipid environment using solution NMR spectroscopy and phospholipid bicelles. The technique is based on the ability of bicelles to form particles with the size, depending on the lipid/detergent ratio. To implement the approach, we report the experimental parameters of "ideal bicelle" models for four kinds of zwitterionic phospholipids, which can be also used in other structural studies. We show that size of bicelles and type of the rim-forming detergent do not affect substantially the spatial structure and stability of the model TM dimer. On the other hand, the effect of bilayer thickness on the free energy of the dimer is dramatic, while the structure of the protein is unchanged in various lipids with fatty chains having a length from 12 to 18 carbon atoms. The obtained data is analyzed using the computer simulations to find the physical origin of the observed effects.
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Affiliation(s)
- P E Bragin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences RAS, str. Miklukho-Maklaya 16/10, Moscow 117997, Russian Federation; Lomonosov Moscow State University, Leninskiye Gory, 1, Moscow 119991, Russian Federation
| | - A S Kuznetsov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences RAS, str. Miklukho-Maklaya 16/10, Moscow 117997, Russian Federation; Moscow Institute of Physics and Technology, Institutsky per., 9, 141700 Dolgoprudnyi, Russian Federation; National Research University Higher School of Economics, Myasnitskaya ul. 20, 101000 Moscow, Russia
| | - O V Bocharova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences RAS, str. Miklukho-Maklaya 16/10, Moscow 117997, Russian Federation; Moscow Institute of Physics and Technology, Institutsky per., 9, 141700 Dolgoprudnyi, Russian Federation
| | - P E Volynsky
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences RAS, str. Miklukho-Maklaya 16/10, Moscow 117997, Russian Federation
| | - A S Arseniev
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences RAS, str. Miklukho-Maklaya 16/10, Moscow 117997, Russian Federation; Moscow Institute of Physics and Technology, Institutsky per., 9, 141700 Dolgoprudnyi, Russian Federation
| | - R G Efremov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences RAS, str. Miklukho-Maklaya 16/10, Moscow 117997, Russian Federation; Moscow Institute of Physics and Technology, Institutsky per., 9, 141700 Dolgoprudnyi, Russian Federation; National Research University Higher School of Economics, Myasnitskaya ul. 20, 101000 Moscow, Russia
| | - K S Mineev
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences RAS, str. Miklukho-Maklaya 16/10, Moscow 117997, Russian Federation; Moscow Institute of Physics and Technology, Institutsky per., 9, 141700 Dolgoprudnyi, Russian Federation.
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22
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Nakao H, Hayashi C, Ikeda K, Saito H, Nagao H, Nakano M. Effects of Hydrophilic Residues and Hydrophobic Length on Flip-Flop Promotion by Transmembrane Peptides. J Phys Chem B 2018; 122:4318-4324. [PMID: 29589918 DOI: 10.1021/acs.jpcb.8b00298] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Peptide-induced phospholipid flip-flop (scrambling) was evaluated using transmembrane model peptides in which the central residue was substituted with various amino acid residues (sequence: Ac-GKK(LA) nXW(LA) nLKKA-CONH2). Peptides with a strongly hydrophilic residue (X = Q, N, or H) had higher scramblase activity than that of other peptides, and the activity was also dependent on the length of the peptides. Peptides with a hydrophobic stretch of 17 residues showed high flip-promotion propensity, whereas those of 21 and 25 residues did not, suggesting that membrane thinning under negative mismatch conditions promotes the flipping. Interestingly, a hydrophobic stretch of 19 residues intensively promoted phospholipid scrambling and membrane leakage. The distinctive characteristics of the peptide were ascribed by long-term molecular dynamics simulation to the arrangement of central glutamine and terminal four lysine residues on the same side of the helix. The combination of simulated and experimental data enables understanding of the mechanisms by which transmembrane helices, and ultimately unidentified scramblases in biomembranes, cause lipid scrambling.
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Affiliation(s)
- Hiroyuki Nakao
- Graduate School of Medicine and Pharmaceutical Sciences , University of Toyama , 2630 Sugitani , Toyama 930-0194 , Japan
| | - Chihiro Hayashi
- Graduate School of Medicine and Pharmaceutical Sciences , University of Toyama , 2630 Sugitani , Toyama 930-0194 , Japan
| | - Keisuke Ikeda
- Graduate School of Medicine and Pharmaceutical Sciences , University of Toyama , 2630 Sugitani , Toyama 930-0194 , Japan
| | - Hiroaki Saito
- Institute of Science and Engineering , Kanazawa University , Kakuma , Kanazawa , Ishikawa 920-1192 , Japan.,Laboratory for Computational Molecular Design , RIKEN Quantitative Biology Center , 6-2-4 Furuedai , Suita , Osaka 565-0874 , Japan
| | - Hidemi Nagao
- Institute of Science and Engineering , Kanazawa University , Kakuma , Kanazawa , Ishikawa 920-1192 , Japan
| | - Minoru Nakano
- Graduate School of Medicine and Pharmaceutical Sciences , University of Toyama , 2630 Sugitani , Toyama 930-0194 , Japan
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23
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Evolution and adaptation of single-pass transmembrane proteins. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:364-377. [DOI: 10.1016/j.bbamem.2017.11.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 10/29/2017] [Accepted: 11/07/2017] [Indexed: 12/19/2022]
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24
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Pawar AB, Sengupta D. Effect of Membrane Composition on Receptor Association: Implications of Cancer Lipidomics on ErbB Receptors. J Membr Biol 2018; 251:359-368. [DOI: 10.1007/s00232-018-0015-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Accepted: 01/15/2018] [Indexed: 10/18/2022]
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25
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Kumar P, Kizhakkedathu JN, Straus SK. Antimicrobial Peptides: Diversity, Mechanism of Action and Strategies to Improve the Activity and Biocompatibility In Vivo. Biomolecules 2018; 8:E4. [PMID: 29351202 PMCID: PMC5871973 DOI: 10.3390/biom8010004] [Citation(s) in RCA: 651] [Impact Index Per Article: 108.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 01/12/2018] [Accepted: 01/12/2018] [Indexed: 02/06/2023] Open
Abstract
Antibiotic resistance is projected as one of the greatest threats to human health in the future and hence alternatives are being explored to combat resistance. Antimicrobial peptides (AMPs) have shown great promise, because use of AMPs leads bacteria to develop no or low resistance. In this review, we discuss the diversity, history and the various mechanisms of action of AMPs. Although many AMPs have reached clinical trials, to date not many have been approved by the US Food and Drug Administration (FDA) due to issues with toxicity, protease cleavage and short half-life. Some of the recent strategies developed to improve the activity and biocompatibility of AMPs, such as chemical modifications and the use of delivery systems, are also reviewed in this article.
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Affiliation(s)
- Prashant Kumar
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada.
- Centre for Blood Research, Department of Pathology and Laboratory Medicine, University of British Columbia, 2350 Health Sciences Mall, Life Sciences Centre, Vancouver, BC V6T 1Z3, Canada.
| | - Jayachandran N Kizhakkedathu
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada.
- Centre for Blood Research, Department of Pathology and Laboratory Medicine, University of British Columbia, 2350 Health Sciences Mall, Life Sciences Centre, Vancouver, BC V6T 1Z3, Canada.
| | - Suzana K Straus
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada.
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26
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Conformational transitions and interactions underlying the function of membrane embedded receptor protein kinases. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1859:1417-1429. [DOI: 10.1016/j.bbamem.2017.01.025] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 01/06/2017] [Accepted: 01/09/2017] [Indexed: 01/08/2023]
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27
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Duneau JP, Khao J, Sturgis JN. Lipid perturbation by membrane proteins and the lipophobic effect. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1859:126-134. [PMID: 27794424 DOI: 10.1016/j.bbamem.2016.10.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 10/21/2016] [Accepted: 10/25/2016] [Indexed: 11/26/2022]
Abstract
Understanding how membrane proteins interact with their environment is fundamental to the understanding of their structure, function and interactions. We have performed coarse-grained molecular dynamics simulations on a series of membrane proteins in a membrane environment to examine the perturbations of the lipids by the presence of protein. We analyze these perturbations in terms of elastic membrane deformations and local lipid protein interactions. However these two factors are insufficient to describe the variety of effects that we observe and the changes caused by membranes proteins to the structure and dynamics of their lipid environment. Other factors that change the conformation available to lipid molecules are evident and are able to modify lipid structure far from the protein surface, and thus mediate long-range interactions between membrane proteins. We suggest that these multiple modifications to lipid behavior are responsible, at the molecular level, for the lipophobic effect we have proposed to account for our observations of membrane protein organization.
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Affiliation(s)
- Jean-Pierre Duneau
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires, UMR 7255, CNRS and Aix-Marseille Univ, Marseille 13402 cedex 20, France.
| | - Jonathan Khao
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires, UMR 7255, CNRS and Aix-Marseille Univ, Marseille 13402 cedex 20, France
| | - James N Sturgis
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires, UMR 7255, CNRS and Aix-Marseille Univ, Marseille 13402 cedex 20, France.
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28
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Windisch D, Ziegler C, Grage SL, Bürck J, Zeitler M, Gor'kov PL, Ulrich AS. Hydrophobic Mismatch Drives the Interaction of E5 with the Transmembrane Segment of PDGF Receptor. Biophys J 2016; 109:737-49. [PMID: 26287626 PMCID: PMC4547410 DOI: 10.1016/j.bpj.2015.07.022] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Revised: 07/13/2015] [Accepted: 07/14/2015] [Indexed: 02/05/2023] Open
Abstract
The oncogenic E5 protein from bovine papillomavirus is a short (44 amino acids long) integral membrane protein that forms homodimers. It activates platelet-derived growth factor receptor (PDGFR) β in a ligand-independent manner by transmembrane helix-helix interactions. The nature of this recognition event remains elusive, as numerous mutations are tolerated in the E5 transmembrane segment, with the exception of one hydrogen-bonding residue. Here, we examined the conformation, stability, and alignment of the E5 protein in fluid lipid membranes of substantially varying bilayer thickness, in both the absence and presence of the PDGFR transmembrane segment. Quantitative synchrotron radiation circular dichroism analysis revealed a very long transmembrane helix for E5 of ∼26 amino acids. Oriented circular dichroism and solid-state 15N-NMR showed that the alignment and stability of this unusually long segment depend critically on the membrane thickness. When reconstituted alone in exceptionally thick DNPC lipid bilayers, the E5 helix was found to be inserted almost upright. In moderately thick bilayers (DErPC and DEiPC), it started to tilt and became slightly deformed, and finally it became aggregated in conventional DOPC, POPC, and DMPC membranes due to hydrophobic mismatch. On the other hand, when E5 was co-reconstituted with the transmembrane segment of PDGFR, it was able to tolerate even the most pronounced mismatch and was stabilized by binding to the receptor, which has the same hydrophobic length. As E5 is known to activate PDGFR within the thin membranes of the Golgi compartment, we suggest that the intrinsic hydrophobic mismatch of these two interaction partners drives them together. They seem to recognize each other by forming a closely packed bundle of mutually aligned transmembrane helices, which is further stabilized by a specific pair of hydrogen-bonding residues.
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Affiliation(s)
- Dirk Windisch
- Institute of Biological Interfaces (IBG-2), Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Colin Ziegler
- Institute of Organic Chemistry, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Stephan L Grage
- Institute of Biological Interfaces (IBG-2), Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Jochen Bürck
- Institute of Biological Interfaces (IBG-2), Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Marcel Zeitler
- Institute of Organic Chemistry, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Peter L Gor'kov
- National High Magnetic Field Laboratory, Tallahassee, Florida
| | - Anne S Ulrich
- Institute of Biological Interfaces (IBG-2), Karlsruhe Institute of Technology, Karlsruhe, Germany; Institute of Organic Chemistry, Karlsruhe Institute of Technology, Karlsruhe, Germany.
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29
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Ackerman DG, Feigenson GW. Effects of Transmembrane α-Helix Length and Concentration on Phase Behavior in Four-Component Lipid Mixtures: A Molecular Dynamics Study. J Phys Chem B 2016; 120:4064-77. [PMID: 27081858 DOI: 10.1021/acs.jpcb.6b00611] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
We used coarse-grained molecular dynamics simulations to examine the effects of transmembrane α-helical WALP peptides on the behavior of four-component lipid mixtures. These mixtures contain a high-melting temperature (high-Tm) lipid, a nanodomain-inducing low-Tm lipid, a macrodomain-inducing low-Tm lipid and cholesterol to model the outer leaflet of cell plasma membranes. In a series of simulations, we incrementally replace the nanodomain-inducing low-Tm lipid by the macrodomain-inducing low-Tm lipid and measure how lipid and phase properties are altered by the addition of WALPs of different length. Regardless of the ratio of the two low-Tm lipids, shorter WALPs increase domain size and all WALPs increase domain alignment between the two leaflets. These effects are smallest for the longest WALP tested, and increase with increasing WALP concentration. Thus, our simulations explain the experimental observation that WALPs induce macroscopic domains in otherwise nanodomain-forming lipid-only mixtures (unpublished). Since the cell plasma membrane contains a large fraction of transmembrane proteins, these findings link the behavior of lipid-only model membranes in vitro to phase behavior in vivo.
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Affiliation(s)
- David G Ackerman
- Department of Molecular Biology and Genetics, Cornell University , Ithaca, New York 14853, United States
| | - Gerald W Feigenson
- Department of Molecular Biology and Genetics, Cornell University , Ithaca, New York 14853, United States
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30
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Rossi G, Monticelli L. Gold nanoparticles in model biological membranes: A computational perspective. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:2380-2389. [PMID: 27060434 DOI: 10.1016/j.bbamem.2016.04.001] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Revised: 03/31/2016] [Accepted: 04/02/2016] [Indexed: 01/15/2023]
Abstract
The electronic, optical, catalytic, and magnetic properties of metal nanoparticles (NPs) make them extremely interesting for biomedical applications. In this rapidly moving field, monolayer-protected gold nanoparticles emerge both as a reference system and as promising candidates for drug and gene delivery, photothermal treatment, and imaging applications. Despite the technological relevance, there is still poor understanding of the molecular processes driving the interactions of metal nanoparticles with cells, and with cell membranes in particular. In this paper we review molecular-level computational studies of the interaction between monolayer-protected gold NPs and model lipid membranes. Our review comprises a brief description of the most relevant experimental results in this field and of the questions they raised, followed by a description of the computational achievements reported so far. This article is part of a Special Issue entitled: Biosimulations edited by Ilpo Vattulainen and Tomasz Róg.
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Affiliation(s)
- Giulia Rossi
- Department of Physics, University of Genoa, via Dodecaneso 33, 16146 Genoa, Italy.
| | - Luca Monticelli
- Molecular Microbiology and Structural Biochemistry (MMSB), CNRS UMR 5086, 7 Passage du Vercors, 69007 Lyon, France.
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31
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Borgese N. Getting membrane proteins on and off the shuttle bus between the endoplasmic reticulum and the Golgi complex. J Cell Sci 2016; 129:1537-45. [PMID: 27029344 DOI: 10.1242/jcs.183335] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Secretory proteins exit the endoplasmic reticulum (ER) in coat protein complex II (COPII)-coated vesicles and then progress through the Golgi complex before delivery to their final destination. Soluble cargo can be recruited to ER exit sites by signal-mediated processes (cargo capture) or by bulk flow. For membrane proteins, a third mechanism, based on the interaction of their transmembrane domain (TMD) with lipid microdomains, must also be considered. In this Commentary, I review evidence in favor of the idea that partitioning of TMDs into bilayer domains that are endowed with distinct physico-chemical properties plays a pivotal role in the transport of membrane proteins within the early secretory pathway. The combination of such self-organizational phenomena with canonical intermolecular interactions is most likely to control the release of membrane proteins from the ER into the secretory pathway.
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Affiliation(s)
- Nica Borgese
- CNR Institute of Neuroscience, Milan 20129, Italy
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32
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Vestergaard M, Kraft JF, Vosegaard T, Thøgersen L, Schiøtt B. Bicelles and Other Membrane Mimics: Comparison of Structure, Properties, and Dynamics from MD Simulations. J Phys Chem B 2015; 119:15831-43. [PMID: 26610232 DOI: 10.1021/acs.jpcb.5b08463] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The increased interest in studying membrane proteins has led to the development of new membrane mimics such as bicelles and nanodiscs. However, only limited knowledge is available of how these membrane mimics are affected by embedded proteins and how well they mimic a lipid bilayer. Herein, we present molecular dynamics simulations to elucidate structural and dynamic properties of small bicelles and compare them to a large alignable bicelle, a small nanodisc, and a lipid bilayer. Properties such as lipid packing and properties related to embedding both an α-helical peptide and a transmembrane protein are investigated. The small bicelles are found to be very dynamic and mainly assume a prolate shape substantiating that small bicelles cannot be regarded as well-defined disclike structures. However, addition of a peptide results in an increased tendency to form disc-shaped bicelles. The small bicelles and the nanodiscs show increased peptide solvation and difference in peptide orientation compared to embedding in a bilayer. The large bicelle imitated a bilayer well with respect to both curvature and peptide solvation, although peripheral binding of short tailed lipids to the embedded proteins is observed, which could hinder ligand binding or multimer formation.
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Affiliation(s)
- Mikkel Vestergaard
- Center for Insoluble Protein Structures (inSPIN), Interdisciplinary Nanoscience Center (iNANO), and Department of Chemistry, Aarhus University , Langelandsgade 140, DK-8000 Aarhus C, Denmark
| | - Johan F Kraft
- Center for Insoluble Protein Structures (inSPIN), Interdisciplinary Nanoscience Center (iNANO), and Department of Chemistry, Aarhus University , Langelandsgade 140, DK-8000 Aarhus C, Denmark
| | - Thomas Vosegaard
- Danish Center for Ultrahigh-Field NMR Spectroscopy and Center for Insoluble Protein Structures (inSPIN), Interdisciplinary Nanoscience Center (iNANO) and Department of Chemistry, Aarhus University , Gustav Wieds Vej 14, DK-8000 Aarhus C, Denmark
| | - Lea Thøgersen
- Center for Membrane Pumps in Cells and Disease (PUMPKIN), Bioinformatics Research Centre, Aarhus University , C.F. Møllers Alle 8, DK-8000 Aarhus C, Denmark
| | - Birgit Schiøtt
- Center for Insoluble Protein Structures (inSPIN), Interdisciplinary Nanoscience Center (iNANO), and Department of Chemistry, Aarhus University , Langelandsgade 140, DK-8000 Aarhus C, Denmark
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33
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Nishizawa M, Nishizawa K. Free energy of helical transmembrane peptide dimerization in OPLS-AA/Berger force field simulations: inaccuracy and implications for partner-specific Lennard-Jones parameters between peptides and lipids. MOLECULAR SIMULATION 2015. [DOI: 10.1080/08927022.2015.1112006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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34
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Bragin PE, Mineev KS, Bocharova OV, Volynsky PE, Bocharov EV, Arseniev AS. HER2 Transmembrane Domain Dimerization Coupled with Self-Association of Membrane-Embedded Cytoplasmic Juxtamembrane Regions. J Mol Biol 2015; 428:52-61. [PMID: 26585403 DOI: 10.1016/j.jmb.2015.11.007] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Revised: 10/23/2015] [Accepted: 11/10/2015] [Indexed: 01/05/2023]
Abstract
Receptor tyrosine kinases of the human epidermal growth factor receptor (HER or ErbB) family transduce biochemical signals across plasma membrane, playing a significant role in vital cellular processes and in various cancers. Inactive HER/ErbB receptors exist in equilibrium between the monomeric and unspecified pre-dimerized states. After ligand binding, the receptors are involved in strong lateral dimerization with proper assembly of their extracellular ligand-binding, single-span transmembrane, and cytoplasmic kinase domains. The dimeric conformation of the HER2 transmembrane domain that is believed to support the cytoplasmic kinase domain configuration corresponding to the receptor active state was previously described in lipid bicelles. Here we used high-resolution NMR spectroscopy in another membrane-mimicking micellar environment and identified an alternative HER2 transmembrane domain dimerization coupled with self-association of membrane-embedded cytoplasmic juxtamembrane region. Such a dimerization mode appears to be capable of effectively inhibiting the receptor kinase activity. This finding refines the molecular mechanism regarding the signal propagation steps from the extracellular to cytoplasmic domains of HER/ErbB receptors.
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Affiliation(s)
- Pavel E Bragin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 16/10 Miklukho-Maklaya Street, Moscow 117997, Russian Federation; Lomonosov Moscow State University, Leninskie Gory, 1, Moscow 119991, Russian Federation
| | - Konstantin S Mineev
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 16/10 Miklukho-Maklaya Street, Moscow 117997, Russian Federation
| | - Olga V Bocharova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 16/10 Miklukho-Maklaya Street, Moscow 117997, Russian Federation
| | - Pavel E Volynsky
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 16/10 Miklukho-Maklaya Street, Moscow 117997, Russian Federation
| | - Eduard V Bocharov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 16/10 Miklukho-Maklaya Street, Moscow 117997, Russian Federation.
| | - Alexander S Arseniev
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 16/10 Miklukho-Maklaya Street, Moscow 117997, Russian Federation; Moscow Institute of Physics and Technology, Institutsky Per., 9, Dolgoprudnyi 141700, Russian Federation
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35
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Nishizawa M, Nishizawa K. Potential of mean force analysis of the self-association of leucine-rich transmembrane α-helices: difference between atomistic and coarse-grained simulations. J Chem Phys 2015; 141:075101. [PMID: 25149815 DOI: 10.1063/1.4891932] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Interaction of transmembrane (TM) proteins is important in many biological processes. Large-scale computational studies using coarse-grained (CG) simulations are becoming popular. However, most CG model parameters have not fully been calibrated with respect to lateral interactions of TM peptide segments. Here, we compare the potential of mean forces (PMFs) of dimerization of TM helices obtained using a MARTINI CG model and an atomistic (AT) Berger lipids-OPLS/AA model (AT(OPLS)). For helical, tryptophan-flanked, leucine-rich peptides (WL15 and WALP15) embedded in a parallel configuration in an octane slab, the AT(OPLS) PMF profiles showed a shallow minimum (with a depth of approximately 3 kJ/mol; i.e., a weak tendency to dimerize). A similar analysis using the CHARMM36 all-atom model (AT(CHARMM)) showed comparable results. In contrast, the CG analysis generally showed steep PMF curves with depths of approximately 16-22 kJ/mol, suggesting a stronger tendency to dimerize compared to the AT model. This CG > AT discrepancy in the propensity for dimerization was also seen for dilauroylphosphatidylcholine (DLPC)-embedded peptides. For a WL15 (and WALP15)/DLPC bilayer system, AT(OPLS) PMF showed a repulsive mean force for a wide range of interhelical distances, in contrast to the attractive forces observed in the octane system. The change from the octane slab to the DLPC bilayer also mitigated the dimerization propensity in the CG system. The dimerization energies of CG (AALALAA)3 peptides in DLPC and dioleoylphosphatidylcholine bilayers were in good agreement with previous experimental data. The lipid headgroup, but not the length of the lipid tails, was a key causative factor contributing to the differences between octane and DLPC. Furthermore, the CG model, but not the AT model, showed high sensitivity to changes in amino acid residues located near the lipid-water interface and hydrophobic mismatch between the peptides and membrane. These findings may help interpret CG and AT simulation results on membrane proteins.
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Affiliation(s)
- Manami Nishizawa
- Teikyo University School of Medical Technology, Itabashi, Tokyo, Japan
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36
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Dynamics of the Glycophorin A Dimer in Membranes of Native-Like Composition Uncovered by Coarse-Grained Molecular Dynamics Simulations. PLoS One 2015. [PMID: 26222139 PMCID: PMC4519189 DOI: 10.1371/journal.pone.0133999] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Membranes are central for cells as borders to the environment or intracellular organelle definition. They are composed of and harbor different molecules like various lipid species and sterols, and they are generally crowded with proteins. The membrane system is very dynamic and components show lateral, rotational and translational diffusion. The consequence of the latter is that phase separation can occur in membranes in vivo and in vitro. It was documented that molecular dynamics simulations of an idealized plasma membrane model result in formation of membrane areas where either saturated lipids and cholesterol (liquid-ordered character, Lo) or unsaturated lipids (liquid-disordered character, Ld) were enriched. Furthermore, current discussions favor the idea that proteins are sorted into the liquid-disordered phase of model membranes, but experimental support for the behavior of isolated proteins in native membranes is sparse. To gain insight into the protein behavior we built a model of the red blood cell membrane with integrated glycophorin A dimer. The sorting and the dynamics of the dimer were subsequently explored by coarse-grained molecular dynamics simulations. In addition, we inspected the impact of lipid head groups and the presence of cholesterol within the membrane on the dynamics of the dimer within the membrane. We observed that cholesterol is important for the formation of membrane areas with Lo and Ld character. Moreover, it is an important factor for the reproduction of the dynamic behavior of the protein found in its native environment. The protein dimer was exclusively sorted into the domain of Ld character in the model red blood cell plasma membrane. Therefore, we present structural information on the glycophorin A dimer distribution in the plasma membrane in the absence of other factors like e.g. lipid anchors in a coarse grain resolution.
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37
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Ho SR, Lee YJ, Lin WC. Regulation of RNF144A E3 Ubiquitin Ligase Activity by Self-association through Its Transmembrane Domain. J Biol Chem 2015. [PMID: 26216882 DOI: 10.1074/jbc.m115.645499] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
RNF144A, an E3 ubiquitin ligase for DNA-dependent protein kinase catalytic subunit (DNA-PKcs), can promote DNA damage-induced cell apoptosis. Here we characterize an important regulation of RNF144A through its transmembrane (TM) domain. The TM domain of RNF144A is highly conserved among species. Deletion of the TM domain abolishes its membrane localization and also significantly reduces its ubiquitin ligase activity. Further evidence shows that the TM domain is required for RNF144A self-association and that the self-association may be partially mediated through a classic GXXXG interaction motif. A mutant RNF144A-G252L/G256L (in the G(252)XXXG(256) motif) preserves membrane localization but is defective in self-association and ubiquitin ligase activity. On the other hand, a membrane localization loss mutant of RNF144A still retains self-association and E3 ligase activity, which can be blocked by additional G252L/G256L mutations. Therefore, our data demonstrate that the TM domain of RNF144A has at least two independent roles, membrane localization and E3 ligase activation, to regulate its physiological function. This regulatory mechanism may be applicable to other RBR (RING1-IBR-RING2) E3 ubiquitin ligases because, first, RNF144B also self-associates. Second, all five TM-containing RBR E3 ligases, including RNF144A and RNF144B, RNF19A/Dorfin, RNF19B, and RNF217, have the RBR-TM(GXXXG) superstructure. Mutations of the GXXXG motifs in RNF144A and RNF217 have also be found in human cancers, including a G252D mutation of RNF144A. Interestingly, RNF144A-G252D still preserves self-association and ubiquitin ligase activity but loses membrane localization and is turned over rapidly. In conclusion, both proper membrane localization and self-association are important for RNF144A function.
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Affiliation(s)
- Shiuh-Rong Ho
- From the Section of Hematology/Oncology, Department of Medicine
| | - Yu-Ju Lee
- Interdepartmental Program in Translational Biology and Molecular Medicine
| | - Weei-Chin Lin
- From the Section of Hematology/Oncology, Department of Medicine, Interdepartmental Program in Translational Biology and Molecular Medicine, Department of Molecular and Cellular Biology, and Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, Texas 77030
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38
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Nyholm TK. Lipid-protein interplay and lateral organization in biomembranes. Chem Phys Lipids 2015; 189:48-55. [DOI: 10.1016/j.chemphyslip.2015.05.008] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Revised: 05/27/2015] [Accepted: 05/29/2015] [Indexed: 01/07/2023]
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39
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Yano Y, Kondo K, Kitani R, Yamamoto A, Matsuzaki K. Cholesterol-Induced Lipophobic Interaction between Transmembrane Helices Using Ensemble and Single-Molecule Fluorescence Resonance Energy Transfer. Biochemistry 2015; 54:1371-9. [DOI: 10.1021/bi501528e] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Yoshiaki Yano
- Graduate School of Pharmaceutical
Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Kotaro Kondo
- Graduate School of Pharmaceutical
Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Ryota Kitani
- Graduate School of Pharmaceutical
Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Arisa Yamamoto
- Graduate School of Pharmaceutical
Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Katsumi Matsuzaki
- Graduate School of Pharmaceutical
Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
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40
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Róg T, Vattulainen I. Cholesterol, sphingolipids, and glycolipids: what do we know about their role in raft-like membranes? Chem Phys Lipids 2014; 184:82-104. [PMID: 25444976 DOI: 10.1016/j.chemphyslip.2014.10.004] [Citation(s) in RCA: 140] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2014] [Revised: 10/24/2014] [Accepted: 10/25/2014] [Indexed: 12/14/2022]
Abstract
Lipids rafts are considered to be functional nanoscale membrane domains enriched in cholesterol and sphingolipids, characteristic in particular of the external leaflet of cell membranes. Lipids, together with membrane-associated proteins, are therefore considered to form nanoscale units with potential specific functions. Although the understanding of the structure of rafts in living cells is quite limited, the possible functions of rafts are widely discussed in the literature, highlighting their importance in cellular functions. In this review, we discuss the understanding of rafts that has emerged based on recent atomistic and coarse-grained molecular dynamics simulation studies on the key lipid raft components, which include cholesterol, sphingolipids, glycolipids, and the proteins interacting with these classes of lipids. The simulation results are compared to experiments when possible.
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Affiliation(s)
- Tomasz Róg
- Department of Physics, Tampere University of Technology, Tampere, Finland
| | - Ilpo Vattulainen
- Department of Physics, Tampere University of Technology, Tampere, Finland; MEMPHYS-Center for Biomembrane Physics, University of Southern Denmark, Odense, Denmark.
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41
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Van Lehn RC, Alexander-Katz A. Membrane-Embedded Nanoparticles Induce Lipid Rearrangements Similar to Those Exhibited by Biological Membrane Proteins. J Phys Chem B 2014; 118:12586-98. [DOI: 10.1021/jp506239p] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Reid C. Van Lehn
- Department of Materials Science
and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Alfredo Alexander-Katz
- Department of Materials Science
and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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42
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Pogozheva ID, Mosberg HI, Lomize AL. Life at the border: adaptation of proteins to anisotropic membrane environment. Protein Sci 2014; 23:1165-96. [PMID: 24947665 DOI: 10.1002/pro.2508] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Revised: 06/17/2014] [Accepted: 06/18/2014] [Indexed: 12/25/2022]
Abstract
This review discusses main features of transmembrane (TM) proteins which distinguish them from water-soluble proteins and allow their adaptation to the anisotropic membrane environment. We overview the structural limitations on membrane protein architecture, spatial arrangement of proteins in membranes and their intrinsic hydrophobic thickness, co-translational and post-translational folding and insertion into lipid bilayers, topogenesis, high propensity to form oligomers, and large-scale conformational transitions during membrane insertion and transport function. Special attention is paid to the polarity of TM protein surfaces described by profiles of dipolarity/polarizability and hydrogen-bonding capacity parameters that match polarity of the lipid environment. Analysis of distributions of Trp resides on surfaces of TM proteins from different biological membranes indicates that interfacial membrane regions with preferential accumulation of Trp indole rings correspond to the outer part of the lipid acyl chain region-between double bonds and carbonyl groups of lipids. These "midpolar" regions are not always symmetric in proteins from natural membranes. We also examined the hydrophobic effect that drives insertion of proteins into lipid bilayer and different free energy contributions to TM protein stability, including attractive van der Waals forces and hydrogen bonds, side-chain conformational entropy, the hydrophobic mismatch, membrane deformations, and specific protein-lipid binding.
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Affiliation(s)
- Irina D Pogozheva
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, Michigan, 48109-1065
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43
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Bereau T, Wang ZJ, Deserno M. More than the sum of its parts: coarse-grained peptide-lipid interactions from a simple cross-parametrization. J Chem Phys 2014; 140:115101. [PMID: 24655203 PMCID: PMC3977883 DOI: 10.1063/1.4867465] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Accepted: 02/04/2014] [Indexed: 11/14/2022] Open
Abstract
Interfacial systems are at the core of fascinating phenomena in many disciplines, such as biochemistry, soft-matter physics, and food science. However, the parametrization of accurate, reliable, and consistent coarse-grained (CG) models for systems at interfaces remains a challenging endeavor. In the present work, we explore to what extent two independently developed solvent-free CG models of peptides and lipids--of different mapping schemes, parametrization methods, target functions, and validation criteria--can be combined by only tuning the cross-interactions. Our results show that the cross-parametrization can reproduce a number of structural properties of membrane peptides (for example, tilt and hydrophobic mismatch), in agreement with existing peptide-lipid CG force fields. We find encouraging results for two challenging biophysical problems: (i) membrane pore formation mediated by the cooperative action of several antimicrobial peptides, and (ii) the insertion and folding of the helix-forming peptide WALP23 in the membrane.
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Affiliation(s)
- Tristan Bereau
- Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
| | - Zun-Jing Wang
- Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
| | - Markus Deserno
- Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
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44
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Chien TH, Chiang YL, Chen CP, Henklein P, Hänel K, Hwang IS, Willbold D, Fischer WB. Assembling an ion channel: ORF 3a from SARS-CoV. Biopolymers 2013; 99:628-35. [PMID: 23483519 PMCID: PMC7161858 DOI: 10.1002/bip.22230] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2012] [Revised: 01/15/2013] [Accepted: 01/28/2013] [Indexed: 11/29/2022]
Abstract
Protein 3a is a 274 amino acid polytopic channel protein with three putative transmembrane domains (TMDs) encoded by severe acute respiratory syndrome corona virus (SARS-CoV). Synthetic peptides corresponding to each of its three individual transmembrane domains (TMDs) are reconstituted into artificial lipid bilayers. Only TMD2 and TMD3 induce channel activity. Reconstitution of the peptides as TMD1 + TMD3 as well as TMD2 + TMD3 in a 1 : 1 mixture induces membrane activity for both mixtures. In a 1 : 1 : 1 mixture, channel like behavior is almost restored. Expression of full length 3a and reconstitution into artificial lipid bilayers reveal a weak cation selective (PK ≈ 2 PCl ) rectifying channel. In the presence of nonphysiological concentration of Ca-ions the channel develops channel activity.
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Affiliation(s)
- Tze-Hsiang Chien
- Institute of Biophotonics, School of Biomedical Science and Engineering, National Yang-Ming University, Taipei, 112, Taiwan
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45
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Formation of raft-like assemblies within clusters of influenza hemagglutinin observed by MD simulations. PLoS Comput Biol 2013; 9:e1003034. [PMID: 23592976 PMCID: PMC3623702 DOI: 10.1371/journal.pcbi.1003034] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2012] [Accepted: 03/03/2013] [Indexed: 11/19/2022] Open
Abstract
The association of hemagglutinin (HA) with lipid rafts in the plasma membrane is an important feature of the assembly process of influenza virus A. Lipid rafts are thought to be small, fluctuating patches of membrane enriched in saturated phospholipids, sphingolipids, cholesterol and certain types of protein. However, raft-associating transmembrane (TM) proteins generally partition into Ld domains in model membranes, which are enriched in unsaturated lipids and depleted in saturated lipids and cholesterol. The reason for this apparent disparity in behavior is unclear, but model membranes differ from the plasma membrane in a number of ways. In particular, the higher protein concentration in the plasma membrane may influence the partitioning of membrane proteins for rafts. To investigate the effect of high local protein concentration, we have conducted coarse-grained molecular dynamics (CG MD) simulations of HA clusters in domain-forming bilayers. During the simulations, we observed a continuous increase in the proportion of raft-type lipids (saturated phospholipids and cholesterol) within the area of membrane spanned by the protein cluster. Lateral diffusion of unsaturated lipids was significantly attenuated within the cluster, while saturated lipids were relatively unaffected. On this basis, we suggest a possible explanation for the change in lipid distribution, namely that steric crowding by the slow-diffusing proteins increases the chemical potential for unsaturated lipids within the cluster region. We therefore suggest that a local aggregation of HA can be sufficient to drive association of the protein with raft-type lipids. This may also represent a general mechanism for the targeting of TM proteins to rafts in the plasma membrane, which is of functional importance in a wide range of cellular processes. The cell membrane is composed of a wide variety of lipids and proteins. Until recently, these were thought to be mixed evenly, but we now have evidence of the existence of “lipid rafts” — small, slow-moving areas of membrane in which certain types of lipid and protein accumulate. Rafts have many important biological functions in healthy cells, but also play a role in the assembly of influenza virus. For example, after the viral protein hemagglutinin is made inside the host cell, it accumulates in rafts. Exiting virus particles then take these portions of cell membrane with them as they leave the host cell. However, the mechanism by which proteins associate with lipid rafts is unclear. Here, we have used computers to simulate lipid membranes containing hemagglutinin. The simulations allow us to look in detail at the motions and interactions of individual proteins and lipids. We found that clusters of proteins altered the properties of nearby lipids, leading to accumulation of raft-type lipids. It therefore appears that aggregation of hemagglutinin may be enough to drive its association with rafts. This helps us to better understand both the influenza assembly process and the properties of lipid rafts.
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46
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Free energy of WALP23 dimer association in DMPC, DPPC, and DOPC bilayers. Chem Phys Lipids 2013; 169:95-105. [DOI: 10.1016/j.chemphyslip.2013.02.001] [Citation(s) in RCA: 100] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Revised: 01/30/2013] [Accepted: 02/01/2013] [Indexed: 11/23/2022]
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47
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Panahi A, Feig M. Dynamic Heterogeneous Dielectric Generalized Born (DHDGB): An implicit membrane model with a dynamically varying bilayer thickness. J Chem Theory Comput 2013; 9:1709-1719. [PMID: 23585740 PMCID: PMC3622271 DOI: 10.1021/ct300975k] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
An extension to the heterogeneous dielectric generalized Born (HDGB) implicit membrane formalism is presented to allow dynamic membrane deformations in response to membrane-inserted biomolecules during molecular dynamic simulations. The flexible membrane is implemented through additional degrees of freedom that represent the membrane deformation at the contact points of a membrane-inserted solute with the membrane. The extra degrees of freedom determine the dielectric and non-polar solvation free energy profiles that are used to obtain the solvation free energy in the presence of the membrane and are used to calculate membrane deformation free energies according to an elastic membrane model. With the dynamic HDGB (DHDGB) model the membrane is able to deform in response to the insertion of charged molecules thereby avoiding the overestimation of insertion free energies with static membrane models. The DHDGB model also allows the membrane to respond to the insertion of membrane-spanning solutes with hydrophobic mismatch. The model is tested with the membrane insertion of amino acid side chain analogs, arginine-containing helices, the WALP23 peptide, and the gramicidin A channel.
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Affiliation(s)
- Afra Panahi
- Department of Chemistry, Michigan State University, East Lansing, MI, 48824
| | - Michael Feig
- Department of Chemistry, Michigan State University, East Lansing, MI, 48824
- Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, MI, 48824
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48
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Membrane lipid saturation activates endoplasmic reticulum unfolded protein response transducers through their transmembrane domains. Proc Natl Acad Sci U S A 2013; 110:4628-33. [PMID: 23487760 DOI: 10.1073/pnas.1217611110] [Citation(s) in RCA: 467] [Impact Index Per Article: 42.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Endoplasmic reticulum (ER) stress sensors use a related luminal domain to monitor the unfolded protein load and convey the signal to downstream effectors, signaling an unfolded protein response (UPR) that maintains compartment-specific protein folding homeostasis. Surprisingly, perturbation of cellular lipid composition also activates the UPR, with important consequences in obesity and diabetes. However, it is unclear if direct sensing of the lipid perturbation contributes to UPR activation. We found that mutant mammalian ER stress sensors, IRE1α and PERK, lacking their luminal unfolded protein stress-sensing domain, nonetheless retained responsiveness to increased lipid saturation. Lipid saturation-mediated activation in cells required an ER-spanning transmembrane domain and was positively regulated in vitro by acyl-chain saturation in reconstituted liposomes. These observations suggest that direct sensing of the lipid composition of the ER membrane contributes to the UPR.
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Matalon E, Kaminker I, Zimmermann H, Eisenstein M, Shai Y, Goldfarb D. Topology of the trans-membrane peptide WALP23 in model membranes under negative mismatch conditions. J Phys Chem B 2013; 117:2280-93. [PMID: 23311473 DOI: 10.1021/jp310056h] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The organization and orientation of membrane-inserted helices is important for better understanding the mode of action of membrane-active peptides and of protein-membrane interactions. Here we report on the application of ESEEM (electron spin-echo envelope modulation) and DEER (double electron-electron resonance) techniques to probe the orientation and oligomeric state of an α-helical trans-membrane model peptide, WALP23, under conditions of negative mismatch between the hydrophobic cores of the model membrane and the peptide. Using ESEEM, we measured weak dipolar interactions between spin-labeled WALP23 and (2)H nuclei of either the solvent (D2O) or of lipids specifically deuterated at the choline group. The ESEEM data obtained from the deuterated lipids were fitted using a model that provided the spin label average distance from a layer of (2)H nuclei in the hydrophilic region of the membrane and the density of the (2)H nuclei in the layer. DEER was used to probe oligomerization through the dipolar interaction between two spin-labels on different peptides. We observed that the center of WALP23 does not coincide with the bilayer midplane and its N-terminus is more buried than the C-terminus. In addition, the ESEEM data fitting yielded a (2)H layer density that was much lower than expected. The DEER experiments revealed the presence of oligomers, the presence of which was attributable to the negative mismatch and the electrostatic dipole of the peptide. A discussion of a possible arrangement of the individual helices in the oligomers that is consistent with the ESEEM and DEER data is presented.
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Affiliation(s)
- Erez Matalon
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot, Israel 76100
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50
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Benjamini A, Smit B. Robust driving forces for transmembrane helix packing. Biophys J 2013; 103:1227-35. [PMID: 22995495 DOI: 10.1016/j.bpj.2012.08.035] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2012] [Revised: 07/31/2012] [Accepted: 08/06/2012] [Indexed: 10/27/2022] Open
Abstract
The packing structures of transmembrane helices are traditionally attributed to patterns in residues along the contact surface. In this view, besides keeping the helices confined in the membrane, the bilayer has only a minor effect on the helices structure. Here, we use two different approaches to show that the lipid environment has a crucial effect in determining the cross-angle distribution of packed helices. We analyzed structural data of a membrane proteins database. We show that the distribution of cross angles of helix pairs in this database is statistically indistinguishable from the cross-angle distribution of two noninteracting helices imbedded in the membrane. These results suggest that the cross angle is, to a large extent, determined by the tilt angle of the individual helices. We test this hypothesis using molecular simulations of a coarse-grained model that contains no specific residue interactions. These simulations reproduce the same cross-angle distribution as found in the database. As the tilt angle of a helix is dominated by hydrophobic mismatch between the protein and surrounding lipids, our results indicate that hydrophobic mismatch is the dominant factor guiding the transmembrane helix packing. Other short-range forces might then fine-tune the structure to its final configuration.
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Affiliation(s)
- Ayelet Benjamini
- Department of Chemistry, University of California, Berkeley, California, USA
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