1
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Huster D, Maiti S, Herrmann A. Phospholipid Membranes as Chemically and Functionally Tunable Materials. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2312898. [PMID: 38456771 DOI: 10.1002/adma.202312898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 02/12/2024] [Indexed: 03/09/2024]
Abstract
The sheet-like lipid bilayer is the fundamental structural component of all cell membranes. Its building blocks are phospholipids and cholesterol. Their amphiphilic structure spontaneously leads to the formation of a bilayer in aqueous environment. Lipids are not just structural elements. Individual lipid species, the lipid membrane structure, and lipid dynamics influence and regulate membrane protein function. An exciting field is emerging where the membrane-associated material properties of different bilayer systems are used in designing innovative solutions for widespread applications across various fields, such as the food industry, cosmetics, nano- and biomedicine, drug storage and delivery, biotechnology, nano- and biosensors, and computing. Here, the authors summarize what is known about how lipids determine the properties and functions of biological membranes and how this has been or can be translated into innovative applications. Based on recent progress in the understanding of membrane structure, dynamics, and physical properties, a perspective is provided on how membrane-controlled regulation of protein functions can extend current applications and even offer new applications.
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Affiliation(s)
- Daniel Huster
- Institute of Medical Physics and Biophysics, University of Leipzig, Härtelstr. 16/18, D-04107, Leipzig, Germany
| | - Sudipta Maiti
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai, 400 005, India
| | - Andreas Herrmann
- Freie Universität Berlin, Department Chemistry and Biochemistry, SupraFAB, Altensteinstr. 23a, D-14195, Berlin, Germany
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2
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Vitali DG, Fonseca D, Carvalho P. The derlin Dfm1 couples retrotranslocation of a folded protein domain to its proteasomal degradation. J Cell Biol 2024; 223:e202308074. [PMID: 38448163 PMCID: PMC11066878 DOI: 10.1083/jcb.202308074] [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: 08/14/2023] [Revised: 12/05/2023] [Accepted: 02/14/2024] [Indexed: 03/08/2024] Open
Abstract
Endoplasmic reticulum (ER) proteins are degraded by proteasomes in the cytosol through ER-associated degradation (ERAD). This process involves the retrotranslocation of substrates across the ER membrane, their ubiquitination, and membrane extraction by the Cdc48/Npl4/Ufd1 ATPase complex prior to delivery to proteasomes for degradation. How the presence of a folded luminal domain affects substrate retrotranslocation and this event is coordinated with subsequent ERAD steps remains unknown. Here, using a model substrate with a folded luminal domain, we showed that Cdc48 ATPase activity is sufficient to drive substrate retrotranslocation independently of ERAD membrane components. However, the complete degradation of the folded luminal domain required substrate-tight coupling of retrotranslocation and proteasomal degradation, which was ensured by the derlin Dfm1. Mutations in Dfm1 intramembrane rhomboid-like or cytosolic Cdc48-binding regions resulted in partial degradation of the substrate with accumulation of its folded domain. Our study revealed Dfm1 as a critical regulator of Cdc48-driven retrotranslocation and highlights the importance of coordinating substrate retrotranslocation and degradation during ERAD.
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Affiliation(s)
- Daniela G. Vitali
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Daniel Fonseca
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Pedro Carvalho
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
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3
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Rout M, Mishra S, Panda S, Dehury B, Pati S. Lipid and cholesterols modulate the dynamics of SARS-CoV-2 viral ion channel ORF3a and its pathogenic variants. Int J Biol Macromol 2024; 254:127986. [PMID: 37944718 DOI: 10.1016/j.ijbiomac.2023.127986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 11/06/2023] [Accepted: 11/07/2023] [Indexed: 11/12/2023]
Abstract
SARS-CoV-2 accessory protein, ORF3a is a putative ion channel which immensely contributes to viral pathogenicity by modulating host immune responses and virus-host interactions. Relatively high expression of ORF3a in diseased individuals and implication with inflammasome activation, apoptosis and autophagy inhibition, ratifies as an effective target for developing vaccines and therapeutics. Herein, we present the elusive dynamics of ORF3a-dimeric state using all-atoms molecular dynamics (MD) simulations at μ-seconds scale in a heterogeneous lipid-mimetic system in multiple replicates. Additionally, we also explore the effect of non-synonymous pathogenic mutations on ORF3a ion channel activity and viral pathogenicity in different SARS-CoV-2 variants using various structure-based protein stability (ΔΔG) tools and computational saturation mutagenesis. Our study ascertains the role of phosphatidylcholines and cholesterol in modulating the structure of ORF3a, which perturbs the size and flexibility of the polar cavity that allows permeation of large cations. Discrete trend in ion channel pore radius and area per lipid arises the premise that presence of lipids might also affect the overall conformation of ORF3a. MD structural-ensembles, in some replicates rationalize the crucial role of TM2 in maintaining the native structure of ORF3a. We also infer that loss of structural stability primarily grounds for pathogenicity in more than half of the pathogenic variants of ORF3a. Overall, the effect of mutation on alteration of ion permeability of ORF3a, proposed in this study brings mechanistic insights into variant consequences on viral membrane proteins of SARS-CoV-2, which can be utilized for the development of novel therapeutics to treat COVID-19 and other coronavirus diseases.
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Affiliation(s)
- Madhusmita Rout
- Bioinformatics Division, ICMR-Regional Medical Research Centre, Chandrasekharpur, Bhubaneswar 751023, Odisha, India
| | - Sarbani Mishra
- Bioinformatics Division, ICMR-Regional Medical Research Centre, Chandrasekharpur, Bhubaneswar 751023, Odisha, India
| | - Sunita Panda
- Mycology Division, ICMR-Regional Medical Research Centre, Chandrasekharpur, Bhubaneswar 751023, Odisha, India
| | - Budheswar Dehury
- Bioinformatics Division, ICMR-Regional Medical Research Centre, Chandrasekharpur, Bhubaneswar 751023, Odisha, India.
| | - Sanghamitra Pati
- Bioinformatics Division, ICMR-Regional Medical Research Centre, Chandrasekharpur, Bhubaneswar 751023, Odisha, India.
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4
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Bohg C, Öster C, Türkaydin B, Lisurek M, Sanchez-Carranza P, Lange S, Utesch T, Sun H, Lange A. The opening dynamics of the lateral gate regulates the activity of rhomboid proteases. SCIENCE ADVANCES 2023; 9:eadh3858. [PMID: 37467320 PMCID: PMC10355837 DOI: 10.1126/sciadv.adh3858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 06/12/2023] [Indexed: 07/21/2023]
Abstract
Rhomboid proteases hydrolyze substrate helices within the lipid bilayer to release soluble domains from the membrane. Here, we investigate the mechanism of activity regulation for this unique but wide-spread protein family. In the model rhomboid GlpG, a lateral gate formed by transmembrane helices TM2 and TM5 was previously proposed to allow access of the hydrophobic substrate to the shielded hydrophilic active site. In our study, we modified the gate region and either immobilized the gate by introducing a maleimide-maleimide (M2M) crosslink or weakened the TM2/TM5 interaction network through mutations. We used solid-state nuclear magnetic resonance (NMR), molecular dynamics (MD) simulations, and molecular docking to investigate the resulting effects on structure and dynamics on the atomic level. We find that variants with increased dynamics at TM5 also exhibit enhanced activity, whereas introduction of a crosslink close to the active site strongly reduces activity. Our study therefore establishes a strong link between the opening dynamics of the lateral gate in rhomboid proteases and their enzymatic activity.
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Affiliation(s)
- Claudia Bohg
- Research Unit Molecular Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Robert-Rössle-Straße 10, 13125 Berlin, Germany
| | - Carl Öster
- Research Unit Molecular Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Robert-Rössle-Straße 10, 13125 Berlin, Germany
| | - Berke Türkaydin
- Research Unit Structural Chemistry & Computational Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Robert-Rössle-Straße 10, 13125 Berlin, Germany
| | - Michael Lisurek
- Research Unit Structural Chemistry & Computational Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Robert-Rössle-Straße 10, 13125 Berlin, Germany
| | - Pascal Sanchez-Carranza
- Research Unit Molecular Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Robert-Rössle-Straße 10, 13125 Berlin, Germany
| | - Sascha Lange
- Research Unit Molecular Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Robert-Rössle-Straße 10, 13125 Berlin, Germany
| | - Tillmann Utesch
- Research Unit Structural Chemistry & Computational Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Robert-Rössle-Straße 10, 13125 Berlin, Germany
| | - Han Sun
- Research Unit Structural Chemistry & Computational Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Robert-Rössle-Straße 10, 13125 Berlin, Germany
- Institute of Chemistry, Technical University of Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - Adam Lange
- Research Unit Molecular Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Robert-Rössle-Straße 10, 13125 Berlin, Germany
- Institut für Biologie, Humboldt-Universität zu Berlin, Invalidenstraße 42, 10115 Berlin, Germany
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5
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White SH. Fifty Years of Biophysics at the Membrane Frontier. Annu Rev Biophys 2023; 52:21-67. [PMID: 36791747 DOI: 10.1146/annurev-biophys-051622-112341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
The author first describes his childhood in the South and the ways in which it fostered the values he has espoused throughout his life, his development of a keen fascination with science, and the influences that supported his progress toward higher education. His experiences in ROTC as a student, followed by two years in the US Army during the Vietnam War, honed his leadership skills. The bulk of the autobiography is a chronological journey through his scientific career, beginning with arrival at the University of California, Irvine in 1972, with an emphasis on the postdoctoral students and colleagues who have contributed substantially to each phase of his lab's progress. White's fundamental findings played a key role in the development of membrane biophysics, helping establish it as fertile ground for research. A story gradually unfolds that reveals the deeply collaborative and painstakingly executed work necessary for a successful career in science.
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Affiliation(s)
- Stephen H White
- Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, California, USA;
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6
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Bhaduri S, Scott NA, Neal SE. The Role of the Rhomboid Superfamily in ER Protein Quality Control: From Mechanisms and Functions to Diseases. Cold Spring Harb Perspect Biol 2023; 15:a041248. [PMID: 35940905 PMCID: PMC9899648 DOI: 10.1101/cshperspect.a041248] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The endoplasmic reticulum (ER) is an essential organelle in eukaryotic cells and is a major site for protein folding, modification, and lipid synthesis. Perturbations within the ER, such as protein misfolding and high demand for protein folding, lead to dysregulation of the ER protein quality control network and ER stress. Recently, the rhomboid superfamily has emerged as a critical player in ER protein quality control because it has diverse cellular functions, including ER-associated degradation (ERAD), endosome Golgi-associated degradation (EGAD), and ER preemptive quality control (ERpQC). This breadth of function both illustrates the importance of the rhomboid superfamily in health and diseases and emphasizes the necessity of understanding their mechanisms of action. Because dysregulation of rhomboid proteins has been implicated in various diseases, such as neurological disorders and cancers, they represent promising potential therapeutic drug targets. This review provides a comprehensive account of the various roles of rhomboid proteins in the context of ER protein quality control and discusses their significance in health and disease.
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Affiliation(s)
- Satarupa Bhaduri
- School of Biological Sciences, the Section of Cell and Developmental Biology, University of California San Diego, La Jolla, California 92093, USA
| | - Nicola A Scott
- School of Biological Sciences, the Section of Cell and Developmental Biology, University of California San Diego, La Jolla, California 92093, USA
| | - Sonya E Neal
- School of Biological Sciences, the Section of Cell and Developmental Biology, University of California San Diego, La Jolla, California 92093, USA
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7
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Engberg O, Ulbricht D, Döbel V, Siebert V, Frie C, Penk A, Lemberg MK, Huster D. Rhomboid-catalyzed intramembrane proteolysis requires hydrophobic matching with the surrounding lipid bilayer. SCIENCE ADVANCES 2022; 8:eabq8303. [PMID: 36149963 PMCID: PMC9506719 DOI: 10.1126/sciadv.abq8303] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Accepted: 08/09/2022] [Indexed: 06/16/2023]
Abstract
Membrane thinning by rhomboid proteins has been proposed to reduce hydrophobic mismatch, providing a unique environment for important functions ranging from intramembrane proteolysis to retrotranslocation in protein degradation. We show by in vitro reconstitution and solid-state nuclear magnetic resonance that the lipid environment of the Escherichia coli rhomboid protease GlpG influences its activity with an optimal hydrophobic membrane thickness between 24 and 26 Å. While phosphatidylcholine membranes are only negligibly altered by GlpG, in an E. coli-relevant lipid mix of phosphatidylethanolamine and phosphatidylglycerol, a thinning by 1.1 Å per leaflet is observed. Protease activity is strongly correlated with membrane thickness and shows no lipid headgroup specificity. We infer from these results that, by adjusting the thickness of specific membrane domains, membrane proteins shape the bilayer for their specific needs.
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Affiliation(s)
- Oskar Engberg
- Institute for Medical Physics and Biophysics, University of Leipzig, Härtelstr. 16/18, D-04107 Leipzig, Germany
| | - David Ulbricht
- Institute for Medical Physics and Biophysics, University of Leipzig, Härtelstr. 16/18, D-04107 Leipzig, Germany
| | - Viola Döbel
- Institute for Medical Physics and Biophysics, University of Leipzig, Härtelstr. 16/18, D-04107 Leipzig, Germany
| | - Verena Siebert
- Center for Molecular Biology of Heidelberg University (ZMBH), Im Neuenheimer Feld 282, D-69120 Heidelberg, Germany
- Center for Biochemistry and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Medical Faculty, University of Cologne, Joseph-Stelzmann-Str. 52, D-50931 Cologne, Germany
| | - Christian Frie
- Center for Biochemistry and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Medical Faculty, University of Cologne, Joseph-Stelzmann-Str. 52, D-50931 Cologne, Germany
| | - Anja Penk
- Institute for Medical Physics and Biophysics, University of Leipzig, Härtelstr. 16/18, D-04107 Leipzig, Germany
| | - Marius K. Lemberg
- Center for Molecular Biology of Heidelberg University (ZMBH), Im Neuenheimer Feld 282, D-69120 Heidelberg, Germany
- Center for Biochemistry and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Medical Faculty, University of Cologne, Joseph-Stelzmann-Str. 52, D-50931 Cologne, Germany
| | - Daniel Huster
- Institute for Medical Physics and Biophysics, University of Leipzig, Härtelstr. 16/18, D-04107 Leipzig, Germany
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8
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Lazaratos M, Siemers M, Brown LS, Bondar AN. Conserved hydrogen-bond motifs of membrane transporters and receptors. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2022; 1864:183896. [PMID: 35217000 DOI: 10.1016/j.bbamem.2022.183896] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 02/04/2022] [Accepted: 02/16/2022] [Indexed: 01/18/2023]
Abstract
Membrane transporters and receptors often rely on conserved hydrogen bonds to assemble transient paths for ion transfer or long-distance conformational couplings. For transporters and receptors that use proton binding and proton transfer for function, inter-helical hydrogen bonds of titratable protein sidechains that could change protonation are of central interest to formulate hypotheses about reaction mechanisms. Knowledge of hydrogen bonds common at sites of potential interest for proton binding could thus inform and guide studies on functional mechanisms of protonation-coupled membrane proteins. Here we apply graph-theory approaches to identify hydrogen-bond motifs of carboxylate and histidine sidechains in a large data set of static membrane protein structures. We find that carboxylate-hydroxyl hydrogen bonds are present in numerous structures of the dataset, and can be part of more extended H-bond clusters that could be relevant to conformational coupling. Carboxylate-carboxyamide and imidazole-imidazole hydrogen bonds are represented in comparably fewer protein structures of the dataset. Atomistic simulations on two membrane transporters in lipid membranes suggest that many of the hydrogen bond motifs present in static protein structures tend to be robust, and can be part of larger hydrogen-bond clusters that recruit additional hydrogen bonds.
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Affiliation(s)
- Michalis Lazaratos
- Freie Universität Berlin, Department of Physics, Theoretical Molecular Biophysics, Arnimallee 14, D14195 Berlin, Germany
| | - Malte Siemers
- Freie Universität Berlin, Department of Physics, Theoretical Molecular Biophysics, Arnimallee 14, D14195 Berlin, Germany
| | - Leonid S Brown
- University of Guelph, Department of Physics, 50 Stone Road E., Guelph, Ontario N1G 2W1, Canada
| | - Ana-Nicoleta Bondar
- Freie Universität Berlin, Department of Physics, Theoretical Molecular Biophysics, Arnimallee 14, D14195 Berlin, Germany; University of Bucharest, Faculty of Physics, Atomiștilor 405, Măgurele 077125, Romania; Forschungszentrum Jülich, Institute for Neuroscience and Medicine and Institute for Advanced Simulations (IAS-5/INM-9), Computational Biomedicine, Wilhelm-Johnen Straße, 52428 Jülich, Germany.
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9
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Maer AM, Rusinova R, Providence LL, Ingólfsson HI, Collingwood SA, Lundbæk JA, Andersen OS. Regulation of Gramicidin Channel Function Solely by Changes in Lipid Intrinsic Curvature. Front Physiol 2022; 13:836789. [PMID: 35350699 PMCID: PMC8957996 DOI: 10.3389/fphys.2022.836789] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 01/28/2022] [Indexed: 11/13/2022] Open
Abstract
Membrane protein function is regulated by the lipid bilayer composition. In many cases the changes in function correlate with changes in the lipid intrinsic curvature (c 0), and c 0 is considered a determinant of protein function. Yet, water-soluble amphiphiles that cause either negative or positive changes in curvature have similar effects on membrane protein function, showing that changes in lipid bilayer properties other than c 0 are important-and may be dominant. To further investigate the mechanisms underlying the bilayer regulation of protein function, we examined how maneuvers that alter phospholipid head groups effective "size"-and thereby c 0-alter gramicidin (gA) channel function. Using dioleoylphospholipids and planar bilayers, we varied the head groups' physical volume and the electrostatic repulsion among head groups (and thus their effective size). When 1,2-dioleyol-sn-glycero-3-phosphocholine (DOPC), was replaced by 1,2-dioleyol-sn-glycero-3-phosphoethanolamine (DOPE) with a smaller head group (causing a more negative c 0), the channel lifetime (τ) is decreased. When the pH of the solution bathing a 1,2-dioleyol-sn-glycero-3-phosphoserine (DOPS) bilayer is decreased from 7 to 3 (causing decreased head group repulsion and a more negative c 0), τ is decreased. When some DOPS head groups are replaced by zwitterionic head groups, τ is similarly decreased. These effects do not depend on the sign of the change in surface charge. In DOPE:DOPC (3:1) bilayers, pH changes from 5→9 to 5→0 (both increasing head group electrostatic repulsion, thereby causing a less negative c 0) both increase τ. Nor do the effects depend on the use of planar, hydrocarbon-containing bilayers, as similar changes were observed in hydrocarbon-free lipid vesicles. Altering the interactions among phospholipid head groups may alter also other bilayer properties such as thickness or elastic moduli. Such changes could be excluded using capacitance measurements and single channel measurements on gA channels of different lengths. We conclude that changes gA channel function caused by changes in head group effective size can be predicted from the expected changes in c 0.
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Affiliation(s)
| | | | | | | | | | | | - Olaf S. Andersen
- Department of Physiology and Biophysics, Weill Cornell Medical College, New York, NY, United States
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10
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Asadi M, Oanca G, Warshel A. Effect of Environmental Factors on the Catalytic Activity of Intramembrane Serine Protease. J Am Chem Soc 2022; 144:1251-1257. [PMID: 35023734 PMCID: PMC10349665 DOI: 10.1021/jacs.1c10494] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The cleavage of protein inside cell membranes regulates pathological pathways and is a subject of major interest. Thus, the nature of the coupling between the physical environment and the function of such proteins has recently attracted significant experimental and theoretical efforts. However, it is difficult to determine the nature of this coupling uniquely by experimental and theoretical studies unless one can separate the chemical and the environmental factors. This work describes calculations of the activation barriers of the intramembrane rhomboid protease in neutral and charged lipid bilayers and in detergent micelle, trying to explore the environmental effect. The calculations of the chemical barrier are done using the empirical valence bond (EVB) method. Additionally, the renormalization method captures the energetics and dynamical effects of the conformational change. The simulations indicate that the physical environment around the rhomboid protease is not a major factor in changing the chemical catalysis and that the conformational and substrate dynamics do not exhibit long-time coupling. General issues about the action of membrane-embedded enzymes are also considered.
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Affiliation(s)
- Mojgan Asadi
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-1062, United States
| | - Gabriel Oanca
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-1062, United States
| | - Arieh Warshel
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-1062, United States
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11
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Nejatfard A, Wauer N, Bhaduri S, Conn A, Gourkanti S, Singh N, Kuo T, Kandel R, Amaro RE, Neal SE. Derlin rhomboid pseudoproteases employ substrate engagement and lipid distortion to enable the retrotranslocation of ERAD membrane substrates. Cell Rep 2021; 37:109840. [PMID: 34686332 PMCID: PMC8641752 DOI: 10.1016/j.celrep.2021.109840] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 07/19/2021] [Accepted: 09/27/2021] [Indexed: 01/13/2023] Open
Abstract
Nearly one-third of proteins are initially targeted to the endoplasmic reticulum (ER) membrane, where they are correctly folded and then delivered to their final cellular destinations. To prevent the accumulation of misfolded membrane proteins, ER-associated degradation (ERAD) moves these clients from the ER membrane to the cytosol, a process known as retrotranslocation. Our recent work in Saccharomyces cerevisiae reveals a derlin rhomboid pseudoprotease, Dfm1, is involved in the retrotranslocation of ubiquitinated ERAD membrane substrates. In this study, we identify conserved residues of Dfm1 that are critical for retrotranslocation. We find several retrotranslocation-deficient Loop 1 mutants that display impaired binding to membrane substrates. Furthermore, Dfm1 possesses lipid thinning function to facilitate in the removal of ER membrane substrates, and this feature is conserved in its human homolog, Derlin-1, further implicating that derlin-mediated retrotranslocation is a well-conserved process.
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Affiliation(s)
- Anahita Nejatfard
- Division of Biological Sciences, Section of Cell and Developmental Biology, University of California San Diego, La Jolla, CA 92093, USA
| | - Nicholas Wauer
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA 92093, USA
| | - Satarupa Bhaduri
- Division of Biological Sciences, Section of Cell and Developmental Biology, University of California San Diego, La Jolla, CA 92093, USA
| | - Adam Conn
- Division of Biological Sciences, Section of Cell and Developmental Biology, University of California San Diego, La Jolla, CA 92093, USA
| | - Saroj Gourkanti
- Division of Biological Sciences, Section of Cell and Developmental Biology, University of California San Diego, La Jolla, CA 92093, USA
| | - Narinderbir Singh
- Division of Biological Sciences, Section of Cell and Developmental Biology, University of California San Diego, La Jolla, CA 92093, USA
| | - Tiffany Kuo
- Division of Biological Sciences, Section of Cell and Developmental Biology, University of California San Diego, La Jolla, CA 92093, USA
| | - Rachel Kandel
- Division of Biological Sciences, Section of Cell and Developmental Biology, University of California San Diego, La Jolla, CA 92093, USA
| | - Rommie E Amaro
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA 92093, USA
| | - Sonya E Neal
- Division of Biological Sciences, Section of Cell and Developmental Biology, University of California San Diego, La Jolla, CA 92093, USA.
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12
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Bohg C, Öster C, Utesch T, Bischoff S, Lange S, Shi C, Sun H, Lange A. A combination of solid-state NMR and MD simulations reveals the binding mode of a rhomboid protease inhibitor. Chem Sci 2021; 12:12754-12762. [PMID: 34703562 PMCID: PMC8494044 DOI: 10.1039/d1sc02146j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 09/01/2021] [Indexed: 11/22/2022] Open
Abstract
Intramembrane proteolysis plays a fundamental role in many biological and pathological processes. Intramembrane proteases thus represent promising pharmacological targets, but few selective inhibitors have been identified. This is in contrast to their soluble counterparts, which are inhibited by many common drugs, and is in part explained by the inherent difficulty to characterize the binding of drug-like molecules to membrane proteins at atomic resolution. Here, we investigated the binding of two different inhibitors to the bacterial rhomboid protease GlpG, an intramembrane protease characterized by a Ser–His catalytic dyad, using solid-state NMR spectroscopy. H/D exchange of deuterated GlpG can reveal the binding position while chemical shift perturbations additionally indicate the allosteric effects of ligand binding. Finally, we determined the exact binding mode of a rhomboid protease-inhibitor using a combination of solid-state NMR and molecular dynamics simulations. We believe this approach can be widely adopted to study the structure and binding of other poorly characterized membrane protein–ligand complexes in a native-like environment and under physiological conditions. Proton-detected solid-state NMR in combination with molecular docking and molecular dynamics (MD) simulations allow the study of rhomboid protease inhibition under native-like conditions.![]()
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Affiliation(s)
- Claudia Bohg
- Department of Molecular Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP) Robert-Rössle-Straße 10 13125 Berlin Germany
| | - Carl Öster
- Department of Molecular Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP) Robert-Rössle-Straße 10 13125 Berlin Germany
| | - Tillmann Utesch
- Structural Chemistry and Computational Biophysics Group, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP) Robert-Rössle-Straße 10 13125 Berlin Germany
| | - Susanne Bischoff
- Department of Molecular Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP) Robert-Rössle-Straße 10 13125 Berlin Germany
| | - Sascha Lange
- Department of Molecular Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP) Robert-Rössle-Straße 10 13125 Berlin Germany
| | - Chaowei Shi
- Department of Molecular Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP) Robert-Rössle-Straße 10 13125 Berlin Germany .,Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, University of Science and Technology of China Huangshan Road 443 Hefei 230027 People's Republic of China
| | - Han Sun
- Structural Chemistry and Computational Biophysics Group, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP) Robert-Rössle-Straße 10 13125 Berlin Germany
| | - Adam Lange
- Department of Molecular Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP) Robert-Rössle-Straße 10 13125 Berlin Germany .,Institut für Biologie, Humboldt-Universität zu Berlin Invalidenstraße 42 10115 Berlin Germany
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13
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Lemberg MK, Strisovsky K. Maintenance of organellar protein homeostasis by ER-associated degradation and related mechanisms. Mol Cell 2021; 81:2507-2519. [PMID: 34107306 DOI: 10.1016/j.molcel.2021.05.004] [Citation(s) in RCA: 64] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 04/14/2021] [Accepted: 05/05/2021] [Indexed: 12/19/2022]
Abstract
Protein homeostasis mechanisms are fundamentally important to match cellular needs and to counteract stress conditions. A fundamental challenge is to understand how defective proteins are recognized and extracted from cellular organelles to be degraded in the cytoplasm. The endoplasmic reticulum (ER)-associated degradation (ERAD) pathway is the best-understood organellar protein quality control system. Here, we review new insights into the mechanism of recognition and retrotranslocation of client proteins in ERAD. In addition to the membrane-integral ERAD E3 ubiquitin ligases, we highlight one protein family that is remarkably often involved in various aspects of membrane protein quality control and protein dislocation: the rhomboid superfamily, which includes derlins and intramembrane serine proteases. Rhomboid-like proteins have been found to control protein homeostasis in the ER, but also in other eukaryotic organelles and in bacteria, pointing toward conserved principles of membrane protein quality control across organelles and evolution.
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Affiliation(s)
- Marius K Lemberg
- Center for Molecular Biology of Heidelberg University (ZMBH), Im Neuenheimer Feld 282, 69120 Heidelberg, Germany; Center for Biochemistry, Medical Faculty, University of Cologne, Joseph-Stelzmann-Strasse 52, 50931 Cologne, Germany.
| | - Kvido Strisovsky
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Prague, Czechia.
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14
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Zhang Y, Zhang S, Xing J, Bahar I. Normal mode analysis of membrane protein dynamics using the vibrational subsystem analysis. J Chem Phys 2021; 154:195102. [PMID: 34240914 PMCID: PMC8131107 DOI: 10.1063/5.0046710] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 05/03/2021] [Indexed: 12/17/2022] Open
Abstract
The vibrational subsystem analysis is a useful approach that allows for evaluating the spectrum of modes of a given system by integrating out the degrees of freedom accessible to the environment. The approach could be utilized for exploring the collective dynamics of a membrane protein (system) coupled to the lipid bilayer (environment). However, the application to membrane proteins is limited due to high computational costs of modeling a sufficiently large membrane environment unbiased by end effects, which drastically increases the size of the investigated system. We derived a recursive formula for calculating the reduced Hessian of a membrane protein embedded in a lipid bilayer by decomposing the membrane into concentric cylindrical domains with the protein located at the center. The approach allows for the design of a time- and memory-efficient algorithm and a mathematical understanding of the convergence of the reduced Hessian with respect to increasing membrane sizes. The application to the archaeal aspartate transporter GltPh illustrates its utility and efficiency in capturing the transporter's elevator-like movement during its transition between outward-facing and inward-facing states.
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Affiliation(s)
- Yan Zhang
- Department of Computational and Systems Biology, University of Pittsburgh, 800 Murdoch Bldg., 3420 Forbes Avenue, Pittsburgh, Pennsylvania 15260, USA
| | - She Zhang
- Department of Computational and Systems Biology, University of Pittsburgh, 800 Murdoch Bldg., 3420 Forbes Avenue, Pittsburgh, Pennsylvania 15260, USA
| | | | - Ivet Bahar
- Department of Computational and Systems Biology, University of Pittsburgh, 800 Murdoch Bldg., 3420 Forbes Avenue, Pittsburgh, Pennsylvania 15260, USA
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15
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Phosphatidylglyerol Lipid Binding at the Active Site of an Intramembrane Protease. J Membr Biol 2020; 253:563-576. [PMID: 33210155 PMCID: PMC7688093 DOI: 10.1007/s00232-020-00152-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 11/04/2020] [Indexed: 10/25/2022]
Abstract
Transmembrane substrate cleavage by the small Escherichia coli rhomboid protease GlpG informs on mechanisms by which lipid interactions shape reaction coordinates of membrane-embedded enzymes. Here, I review and discuss new work on the molecular picture of protein-lipid interactions that might govern the formation of the substrate-enzyme complex in fluid lipid membranes. Negatively charged PG-type lipids are of particular interest, because they are a major component of bacterial membranes. Atomistic computer simulations indicate POPG and DOPG lipids bridge remote parts of GlpG and might pre-occupy the substrate-docking site. Inhibition of catalytic activity by PG lipids could arise from ligand-like lipid binding at the active site, which could delay or prevent substrate docking. Dynamic protein-lipid H-bond networks, water access to the active site, and fluctuations in the orientation of GlpG suggest that GlpG has lipid-coupled dynamics that could shape the energy landscape of transmembrane substrate docking.
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16
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Kandel RR, Neal SE. The role of rhomboid superfamily members in protein homeostasis: Mechanistic insight and physiological implications. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2020; 1867:118793. [PMID: 32645330 PMCID: PMC7434706 DOI: 10.1016/j.bbamcr.2020.118793] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 05/30/2020] [Accepted: 07/01/2020] [Indexed: 12/11/2022]
Abstract
Cells are equipped with protein quality control pathways in order to maintain a healthy proteome; a process known as protein homeostasis. Dysfunction in protein homeostasis leads to the development of many diseases that are associated with proteinopathies. Recently, the rhomboid superfamily has attracted much attention concerning their involvement in protein homeostasis. While their functional role has become much clearer in the last few years, their systemic significance in mammals remains elusive. Here we delineate the current knowledge of rhomboids in protein quality control and how these functions are integrated at the organismal level.
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Affiliation(s)
- Rachel R Kandel
- Division of Biological Sciences, Section of Cell and Developmental Biology, University of California San Diego, La Jolla, CA 92093, United States of America
| | - Sonya E Neal
- Division of Biological Sciences, Section of Cell and Developmental Biology, University of California San Diego, La Jolla, CA 92093, United States of America.
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17
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Mihaljević L, Urban S. Decoding the Functional Evolution of an Intramembrane Protease Superfamily by Statistical Coupling Analysis. Structure 2020; 28:1329-1336.e4. [PMID: 32795403 DOI: 10.1016/j.str.2020.07.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 06/12/2020] [Accepted: 07/24/2020] [Indexed: 11/18/2022]
Abstract
How evolution endowed membrane enzymes with specific abilities, and then tuned them to the needs of different cells, is poorly understood. We examined whether statistical coupling analysis (SCA) can be applied to rhomboid proteases, the most widely distributed membrane proteins, to identify amino acid "sectors" that evolved independently to acquire a specific function. SCA revealed three coevolving residue networks that form two sectors. Sector 1 determines substrate specificity, but is paradoxically scattered across the protein, consistent with dynamics driving rhomboid-substrate interactions. Sector 2 is hierarchically composed of a subgroup that maintains the catalytic site, and another that maintains the overall fold, forecasting evolution of rhomboid pseudoproteases. Changing only sector 1 residues of a "recipient" rhomboid converted its substrate specificity and catalytic efficiency to that of the "donor." While used only twice over a decade ago, SCA should be generally applicable to membrane proteins, and our sector grafting approach provides an efficient strategy for designing enzymes.
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Affiliation(s)
- Ljubica Mihaljević
- Department of Molecular Biology & Genetics, Johns Hopkins University School of Medicine, Room 507 PCTB, 725 North Wolfe Street, Baltimore, MD 21205, USA
| | - Siniša Urban
- Department of Molecular Biology & Genetics, Johns Hopkins University School of Medicine, Room 507 PCTB, 725 North Wolfe Street, Baltimore, MD 21205, USA.
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18
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Lysyk L, Brassard R, Touret N, Lemieux MJ. PARL Protease: A Glimpse at Intramembrane Proteolysis in the Inner Mitochondrial Membrane. J Mol Biol 2020; 432:5052-5062. [DOI: 10.1016/j.jmb.2020.04.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 04/03/2020] [Accepted: 04/07/2020] [Indexed: 01/07/2023]
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19
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Stix R, Lee CJ, Faraldo-Gómez JD, Banerjee A. Structure and Mechanism of DHHC Protein Acyltransferases. J Mol Biol 2020; 432:4983-4998. [PMID: 32522557 DOI: 10.1016/j.jmb.2020.05.023] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 05/26/2020] [Accepted: 05/28/2020] [Indexed: 01/01/2023]
Abstract
S-acylation, whereby a fatty acid chain is covalently linked to a cysteine residue by a thioester linkage, is the most prevalent kind of lipid modification of proteins. Thousands of proteins are targets of this post-translational modification, which is catalyzed by a family of eukaryotic integral membrane enzymes known as DHHC protein acyltransferases (DHHC-PATs). Our knowledge of the repertoire of S-acylated proteins has been rapidly expanding owing to development of the chemoproteomic techniques. There has also been an increasing number of reports in the literature documenting the importance of S-acylation in human physiology and disease. Recently, the first atomic structures of two different DHHC-PATs were determined using X-ray crystallography. This review will focus on the insights gained into the molecular mechanism of DHHC-PATs from these structures and highlight representative data from the biochemical literature that they help explain.
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Affiliation(s)
- Robyn Stix
- Theoretical Molecular Biophysics Laboratory, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Chul-Jin Lee
- Unit on Structural and Chemical Biology of Membrane Proteins, Neurosciences and Cellular and Structural Biology Division, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - José D Faraldo-Gómez
- Theoretical Molecular Biophysics Laboratory, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Anirban Banerjee
- Unit on Structural and Chemical Biology of Membrane Proteins, Neurosciences and Cellular and Structural Biology Division, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
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20
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Wu X, Siggel M, Ovchinnikov S, Mi W, Svetlov V, Nudler E, Liao M, Hummer G, Rapoport TA. Structural basis of ER-associated protein degradation mediated by the Hrd1 ubiquitin ligase complex. Science 2020; 368:368/6489/eaaz2449. [PMID: 32327568 DOI: 10.1126/science.aaz2449] [Citation(s) in RCA: 133] [Impact Index Per Article: 33.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2019] [Revised: 01/18/2020] [Accepted: 03/11/2020] [Indexed: 12/13/2022]
Abstract
Misfolded luminal endoplasmic reticulum (ER) proteins undergo ER-associated degradation (ERAD-L): They are retrotranslocated into the cytosol, polyubiquitinated, and degraded by the proteasome. ERAD-L is mediated by the Hrd1 complex (composed of Hrd1, Hrd3, Der1, Usa1, and Yos9), but the mechanism of retrotranslocation remains mysterious. Here, we report a structure of the active Hrd1 complex, as determined by cryo-electron microscopy analysis of two subcomplexes. Hrd3 and Yos9 jointly create a luminal binding site that recognizes glycosylated substrates. Hrd1 and the rhomboid-like Der1 protein form two "half-channels" with cytosolic and luminal cavities, respectively, and lateral gates facing one another in a thinned membrane region. These structures, along with crosslinking and molecular dynamics simulation results, suggest how a polypeptide loop of an ERAD-L substrate moves through the ER membrane.
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Affiliation(s)
- Xudong Wu
- Howard Hughes Medical Institute and Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Marc Siggel
- Department of Theoretical Biophysics, Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany
| | - Sergey Ovchinnikov
- Faculty of Arts and Sciences, Center for Systems Biology, Harvard University, Cambridge, MA 02138, USA
| | - Wei Mi
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA.,Present address: Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Vladimir Svetlov
- Howard Hughes Medical Institute and Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA
| | - Evgeny Nudler
- Howard Hughes Medical Institute and Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA
| | - Maofu Liao
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Gerhard Hummer
- Department of Theoretical Biophysics, Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany.,Institute of Biophysics, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
| | - Tom A Rapoport
- Howard Hughes Medical Institute and Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA.
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21
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Stix R, Song J, Banerjee A, Faraldo-Gómez JD. DHHC20 Palmitoyl-Transferase Reshapes the Membrane to Foster Catalysis. Biophys J 2019; 118:980-988. [PMID: 31858978 DOI: 10.1016/j.bpj.2019.11.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 10/22/2019] [Accepted: 11/08/2019] [Indexed: 12/20/2022] Open
Abstract
Cysteine palmitoylation, a form of S-acylation, is a key posttranslational modification in cellular signaling. This type of reversible lipidation occurs in both plasma and organellar membranes, and is catalyzed by a family of integral membrane proteins known as DHHC acyltransferases. The first step in the S-acylation process is the recognition of free acyl coenzyme A (acyl-CoA) from the lipid bilayer. The DHHC enzyme then becomes autoacylated at a site defined by a conserved Asp-His-His-Cys motif. This reaction entails ionization of the catalytic Cys. Intriguingly, in known DHHC structures, this catalytic Cys appears to be exposed to the hydrophobic interior of the lipid membrane, which would be highly unfavorable for a negatively charged nucleophile, thus hindering autoacylation. Here, we use biochemical and computational methods to reconcile these seemingly contradictory facts. First, we experimentally demonstrate that human DHHC20 is active when reconstituted in POPC nanodiscs. Microsecond-long all-atom molecular dynamics simulations are then calculated for human DHHC20 and for different acyl-CoA forms, also in a POPC membrane. Strikingly, we observe that human DHHC20 induces a drastic deformation in the membrane, particularly on the cytoplasmic side, where autoacylation occurs. As a result, the catalytic Cys becomes hydrated and optimally positioned to encounter the cleavage site in acyl-CoA. In summary, we hypothesize that DHHC enzymes locally reshape the membrane to foster a morphology that is specifically adapted for acyl-CoA recognition and autoacylation.
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Affiliation(s)
- Robyn Stix
- Theoretical Molecular Biophysics Laboratory, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland; Unit on Structural and Chemical Biology of Membrane Proteins, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland
| | - James Song
- Unit on Structural and Chemical Biology of Membrane Proteins, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland
| | - Anirban Banerjee
- Unit on Structural and Chemical Biology of Membrane Proteins, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland.
| | - José D Faraldo-Gómez
- Theoretical Molecular Biophysics Laboratory, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland.
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22
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Almeida-Hernandez Y, Tidow H. Soluble Regions of GlpG Influence Protein–Lipid Interactions and Lipid Distribution. J Phys Chem B 2019; 123:7852-7858. [DOI: 10.1021/acs.jpcb.9b06943] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yasser Almeida-Hernandez
- Department of Chemistry, Institute for Biochemistry and Molecular Biology, University of Hamburg, Martin-Luther-King-Platz 6, Hamburg D-20146, Germany
- The Hamburg Centre for Ultrafast Imaging, University of Hamburg, Luruper Chaussee 149, Hamburg D-22761, Germany
| | - Henning Tidow
- Department of Chemistry, Institute for Biochemistry and Molecular Biology, University of Hamburg, Martin-Luther-King-Platz 6, Hamburg D-20146, Germany
- The Hamburg Centre for Ultrafast Imaging, University of Hamburg, Luruper Chaussee 149, Hamburg D-22761, Germany
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23
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Kreutzberger AJB, Ji M, Aaron J, Mihaljević L, Urban S. Rhomboid distorts lipids to break the viscosity-imposed speed limit of membrane diffusion. Science 2019; 363:363/6426/eaao0076. [PMID: 30705155 DOI: 10.1126/science.aao0076] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Revised: 10/30/2018] [Accepted: 12/07/2018] [Indexed: 12/25/2022]
Abstract
Enzymes that cut proteins inside membranes regulate diverse cellular events, including cell signaling, homeostasis, and host-pathogen interactions. Adaptations that enable catalysis in this exceptional environment are poorly understood. We visualized single molecules of multiple rhomboid intramembrane proteases and unrelated proteins in living cells (human and Drosophila) and planar lipid bilayers. Notably, only rhomboid proteins were able to diffuse above the Saffman-Delbrück viscosity limit of the membrane. Hydrophobic mismatch with the irregularly shaped rhomboid fold distorted surrounding lipids and propelled rhomboid diffusion. The rate of substrate processing in living cells scaled with rhomboid diffusivity. Thus, intramembrane proteolysis is naturally diffusion-limited, but cells mitigate this constraint by using the rhomboid fold to overcome the "speed limit" of membrane diffusion.
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Affiliation(s)
- Alex J B Kreutzberger
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Room 507 PCTB, 725 North Wolfe Street, Baltimore, MD 21205, USA
| | - Ming Ji
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Room 507 PCTB, 725 North Wolfe Street, Baltimore, MD 21205, USA
| | - Jesse Aaron
- Howard Hughes Medical Institute, Advanced Imaging Center, Janelia Research Campus, 19700 Helix Drive, Ashburn, VA 20147, USA
| | - Ljubica Mihaljević
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Room 507 PCTB, 725 North Wolfe Street, Baltimore, MD 21205, USA
| | - Siniša Urban
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Room 507 PCTB, 725 North Wolfe Street, Baltimore, MD 21205, USA. .,Howard Hughes Medical Institute, Advanced Imaging Center, Janelia Research Campus, 19700 Helix Drive, Ashburn, VA 20147, USA
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24
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Goder V, Alanis-Dominguez E, Bustamante-Sequeiros M. Lipids and their (un)known effects on ER-associated protein degradation (ERAD). Biochim Biophys Acta Mol Cell Biol Lipids 2019; 1865:158488. [PMID: 31233887 DOI: 10.1016/j.bbalip.2019.06.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 06/15/2019] [Accepted: 06/18/2019] [Indexed: 02/09/2023]
Abstract
Endoplasmic reticulum (ER)-associated protein degradation (ERAD) is a conserved cellular process that apart from protein quality control and maintenance of ER membrane identity has pivotal functions in regulating the lipid composition of the ER membrane. A general trigger for ERAD activation is the exposure of normally buried protein domains due to protein misfolding, absence of binding partners or conformational changes. Several feedback loops for ER lipid homeostasis exploit the induction of conformational changes in key enzymes of lipid biosynthesis or in ER membrane-embedded transcription factors upon shortage or abundance of specific lipids, leading to enzyme degradation or mobilization of transcription factors. Similarly, an insufficient amount of lipids triggers ERAD of apolipoproteins during lipoprotein formation. Lipids might even have a role in ER protein quality control: when proteins destined for ER export are covalently modified with lipids their ER residence time and their susceptibility to ERAD is reduced. Here we summarize and compare the various interconnections of lipids with ER membrane proteins and ERAD. This article is part of a Special Issue entitled Endoplasmic reticulum platforms for lipid dynamics edited by Shamshad Cockcroft and Christopher Stefan.
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Affiliation(s)
- Veit Goder
- Department of Genetics, University of Seville, 6, Ave Reina Mercedes, 41012 Seville, Spain.
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25
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Paschkowsky S, Hsiao JM, Young JC, Munter LM. The discovery of proteases and intramembrane proteolysis. Biochem Cell Biol 2019; 97:265-269. [DOI: 10.1139/bcb-2018-0186] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
- Sandra Paschkowsky
- Department of Pharmacology & Therapeutics, McGill University, Bellini Life Sciences Complex, 3649 Promenade Sir William Osler, Montreal, QC H3G 0B1, Canada
| | - Jacqueline Melissa Hsiao
- Department of Biochemistry, McGill University, McIntyre Building, 3655 Promenade Sir William Osler, Montreal, QC H3G 1Y6, Canada
| | - Jason C. Young
- Department of Biochemistry, McGill University, McIntyre Building, 3655 Promenade Sir William Osler, Montreal, QC H3G 1Y6, Canada
| | - Lisa Marie Munter
- Department of Pharmacology & Therapeutics, McGill University, Bellini Life Sciences Complex, 3649 Promenade Sir William Osler, Montreal, QC H3G 0B1, Canada
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26
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Muller MP, Jiang T, Sun C, Lihan M, Pant S, Mahinthichaichan P, Trifan A, Tajkhorshid E. Characterization of Lipid-Protein Interactions and Lipid-Mediated Modulation of Membrane Protein Function through Molecular Simulation. Chem Rev 2019; 119:6086-6161. [PMID: 30978005 PMCID: PMC6506392 DOI: 10.1021/acs.chemrev.8b00608] [Citation(s) in RCA: 153] [Impact Index Per Article: 30.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The cellular membrane constitutes one of the most fundamental compartments of a living cell, where key processes such as selective transport of material and exchange of information between the cell and its environment are mediated by proteins that are closely associated with the membrane. The heterogeneity of lipid composition of biological membranes and the effect of lipid molecules on the structure, dynamics, and function of membrane proteins are now widely recognized. Characterization of these functionally important lipid-protein interactions with experimental techniques is however still prohibitively challenging. Molecular dynamics (MD) simulations offer a powerful complementary approach with sufficient temporal and spatial resolutions to gain atomic-level structural information and energetics on lipid-protein interactions. In this review, we aim to provide a broad survey of MD simulations focusing on exploring lipid-protein interactions and characterizing lipid-modulated protein structure and dynamics that have been successful in providing novel insight into the mechanism of membrane protein function.
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Affiliation(s)
- Melanie P. Muller
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology
- Department of Biochemistry
- Center for Biophysics and Quantitative Biology
- College of Medicine
- University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Tao Jiang
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology
- Department of Biochemistry
- Center for Biophysics and Quantitative Biology
- University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Chang Sun
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology
- Department of Biochemistry
- University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Muyun Lihan
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology
- Department of Biochemistry
- Center for Biophysics and Quantitative Biology
- University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Shashank Pant
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology
- Department of Biochemistry
- Center for Biophysics and Quantitative Biology
- University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Paween Mahinthichaichan
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology
- Department of Biochemistry
- University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Anda Trifan
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology
- Department of Biochemistry
- Center for Biophysics and Quantitative Biology
- University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Emad Tajkhorshid
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology
- Department of Biochemistry
- Center for Biophysics and Quantitative Biology
- College of Medicine
- University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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27
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Bondar AN. Mechanisms by Which Lipids Influence Conformational Dynamics of the GlpG Intramembrane Protease. J Phys Chem B 2019; 123:4159-4172. [PMID: 31059259 DOI: 10.1021/acs.jpcb.8b11291] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Rhomboid intramembrane proteases are bound to lipid membranes, where they dock and cleave other transmembrane substrates. How the lipid membrane surrounding the protease impacts the conformational dynamics of the protease is essential to understand because it informs on the reaction coordinate of substrate binding. Atomistic molecular dynamics simulations allow us to probe protein motions and characterize the coupling between protein and lipids. Simulations performed here on GlpG, the rhomboid protease from Escherichia coli, indicate that the thickness of the lipid membrane close to GlpG depends on both the composition of the lipid membrane and the conformation of GlpG. Transient binding of a lipid headgroup at the active site of the protease, as observed in some of the simulations reported here, suggests that a lipid headgroup might compete with the substrate for access to the GlpG active site. Interactions identified between lipid headgroups and the protein influence the dynamics of lipid interactions close to the substrate-binding site. These observations suggest that the lipid membrane environment shapes the energy profile of the substrate-docking region of the enzyme reaction coordinate.
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Affiliation(s)
- Ana-Nicoleta Bondar
- Freie Universität Berlin , Department of Physics, Theoretical Molecular Biophysics Group , Arnimallee 14 , D-14195 Berlin , Germany
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28
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Abstract
Membranes surrounding the biological cell and its internal compartments host proteins that catalyze chemical reactions essential for the functioning of the cell. Rather than being a passive structural matrix that holds membrane-embedded proteins in place, the membrane can largely shape the conformational energy landscape of membrane proteins and impact the energetics of their chemical reaction. Here, we highlight the challenges in understanding how lipids impact the conformational energy landscape of macromolecular membrane complexes whose functioning involves chemical reactions including proton transfer. We review here advances in our understanding of how chemical reactions occur at membrane interfaces gleaned with both theoretical and experimental advances using simple protein systems as guides. Our perspective is that of bridging experiments with theory to understand general physicochemical principles of membrane reactions, with a long term goal of furthering our understanding of the role of the lipids on the functioning of complex macromolecular assemblies at the membrane interface.
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Affiliation(s)
- Ana-Nicoleta Bondar
- Freie Universität Berlin , Department of Physics, Theoretical Molecular Biophysics Group , Arnimallee 14 , D-14195 Berlin , Germany
| | - M Joanne Lemieux
- University of Alberta , Department of Biochemistry, Membrane Protein Disease Research Group , Edmonton , Alberta T6G 2H7 , Canada
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29
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Affiliation(s)
- Michael S Wolfe
- Department of Medicinal Chemistry, University of Kansas, Lawrence, KS, USA.
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30
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Avci D, Lemberg MK. Membrane Protein Dislocation by the Rhomboid Pseudoprotease Dfm1: No Pore Needed? Mol Cell 2018; 69:161-162. [PMID: 29351840 DOI: 10.1016/j.molcel.2017.12.031] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Defective ER-resident membrane proteins need to be ejected into the cytoplasm in order to be degraded by the proteasome, but the exact mechanism remains unclear. In this issue of Molecular Cell, Neal et al. (2018) reveal that the rhomboid pseudoprotease Dfm1 defines the central ERAD component for membrane protein dislocation.
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Affiliation(s)
- Dönem Avci
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, 69120 Heidelberg, Germany
| | - Marius K Lemberg
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, 69120 Heidelberg, Germany.
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31
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The Rhomboid Superfamily: Structural Mechanisms and Chemical Biology Opportunities. Trends Biochem Sci 2018; 43:726-739. [DOI: 10.1016/j.tibs.2018.06.009] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2018] [Revised: 06/08/2018] [Accepted: 06/30/2018] [Indexed: 12/27/2022]
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32
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Paschkowsky S, Recinto SJ, Young JC, Bondar AN, Munter LM. Membrane cholesterol as regulator of human rhomboid protease RHBDL4. J Biol Chem 2018; 293:15556-15568. [PMID: 30143535 DOI: 10.1074/jbc.ra118.002640] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Revised: 08/18/2018] [Indexed: 12/28/2022] Open
Abstract
In the last decade, intramembrane proteases have gained increasing attention because of their many links to various diseases. Nevertheless, our understanding as to how they function or how they are regulated is still limited, especially when it comes to human homologues. In this regard, here we sought to unravel mechanisms of regulation of the protease rhomboid-like protein-4 (RHBDL4), one of five active human serine intramembrane proteases. In view of our recent finding that human RHBDL4 efficiently cleaves the amyloid precursor protein (APP), a key protein in the pathology of Alzheimer's disease, we used established reagents to modulate the cellular cholesterol content and analyzed the effects of this modulation on RHBDL4-mediated processing of endogenous APP. We discovered that lowering membrane cholesterol levels increased the levels of RHBDL4-specific endogenous APP fragments, whereas high cholesterol levels had the opposite effect. Direct binding of cholesterol to APP did not mediate these modulating effects of cholesterol. Instead, using homology modeling, we identified two potential cholesterol-binding motifs in the transmembrane helices 3 and 6 of RHBDL4. Substitution of the essential tyrosine residues of the potential cholesterol-binding motifs to alanine increased the levels of endogenous APP C-terminal fragments, reflecting enhanced RHBDL4 activity. In summary, we provide evidence that the activity of RHBDL4 is regulated by cholesterol likely through a direct binding of cholesterol to the enzyme.
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Affiliation(s)
- Sandra Paschkowsky
- From the Department of Pharmacology and Therapeutics and Cell Information Systems Group and
| | | | - Jason C Young
- Department of Biochemistry and Groupe de Recherche Axé sur la Structure des Protéines, McGill University, Montreal, Quebec H3G 0B1, Canada and
| | - Ana-Nicoleta Bondar
- the Department of Physics, Theoretical Molecular Biophysics, Freie Universität Berlin, Arnimallee 14, Berlin 14195, Germany
| | - Lisa Marie Munter
- From the Department of Pharmacology and Therapeutics and Cell Information Systems Group and
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Lichtenthaler SF, Lemberg MK, Fluhrer R. Proteolytic ectodomain shedding of membrane proteins in mammals-hardware, concepts, and recent developments. EMBO J 2018; 37:e99456. [PMID: 29976761 PMCID: PMC6068445 DOI: 10.15252/embj.201899456] [Citation(s) in RCA: 189] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 05/05/2018] [Accepted: 06/18/2018] [Indexed: 12/14/2022] Open
Abstract
Proteolytic removal of membrane protein ectodomains (ectodomain shedding) is a post-translational modification that controls levels and function of hundreds of membrane proteins. The contributing proteases, referred to as sheddases, act as important molecular switches in processes ranging from signaling to cell adhesion. When deregulated, ectodomain shedding is linked to pathologies such as inflammation and Alzheimer's disease. While proteases of the "a disintegrin and metalloprotease" (ADAM) and "beta-site APP cleaving enzyme" (BACE) families are widely considered as sheddases, in recent years a much broader range of proteases, including intramembrane and soluble proteases, were shown to catalyze similar cleavage reactions. This review demonstrates that shedding is a fundamental process in cell biology and discusses the current understanding of sheddases and their substrates, molecular mechanisms and cellular localizations, as well as physiological functions of protein ectodomain shedding. Moreover, we provide an operational definition of shedding and highlight recent conceptual advances in the field. While new developments in proteomics facilitate substrate discovery, we expect that shedding is not a rare exception, but rather the rule for many membrane proteins, and that many more interesting shedding functions await discovery.
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Affiliation(s)
- Stefan F Lichtenthaler
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
- Neuroproteomics, Klinikum rechts der Isar, School of Medicine, and Institute for Advanced Study, Technical University Munich, Munich, Germany
- Munich Center for Systems Neurology (SyNergy), Munich, Germany
| | - Marius K Lemberg
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Regina Fluhrer
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
- Biomedizinisches Centrum (BMC), Ludwig-Maximilians University of Munich, Munich, Germany
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34
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Membrane properties that shape the evolution of membrane enzymes. Curr Opin Struct Biol 2018; 51:80-91. [PMID: 29597094 DOI: 10.1016/j.sbi.2018.03.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Revised: 03/14/2018] [Accepted: 03/15/2018] [Indexed: 02/07/2023]
Abstract
Spectacular recent progress in structural biology has led to determination of the structures of many integral membrane enzymes that catalyze reactions in which at least one substrate also is membrane bound. A pattern of results seems to be emerging in which the active site chemistry of these enzymes is usually found to be analogous to what is observed for water soluble enzymes catalyzing the same reaction types. However, in light of the chemical, structural, and physical complexity of cellular membranes plus the presence of transmembrane gradients and potentials, these enzymes may be subject to membrane-specific regulatory mechanisms that are only now beginning to be uncovered. We review the membrane-specific environmental traits that shape the evolution of membrane-embedded biocatalysts.
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Embedded in the Membrane: How Lipids Confer Activity and Specificity to Intramembrane Proteases. J Membr Biol 2017; 251:369-378. [PMID: 29260282 DOI: 10.1007/s00232-017-0008-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 12/12/2017] [Indexed: 10/18/2022]
Abstract
Proteases, sharp yet unforgivable tools of every cell, require tight regulation to ensure specific non-aberrant cleavages. The relatively recent discovered class of intramembrane proteases has gained increasing interest due to their involvement in important signaling pathways linking them to diseases including Alzheimer's disease and cancer. Despite tremendous efforts, their regulatory mechanisms have only started to unravel. There is evidence that the membrane composition itself can regulate intramembrane protease activity and specificity. In this review, we highlight the work on γ-secretase and rhomboid proteases and summarize several studies as to how different lipids impact on enzymatic activity.
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36
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Düsterhöft S, Künzel U, Freeman M. Rhomboid proteases in human disease: Mechanisms and future prospects. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2017; 1864:2200-2209. [PMID: 28460881 DOI: 10.1016/j.bbamcr.2017.04.016] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 04/24/2017] [Accepted: 04/26/2017] [Indexed: 01/19/2023]
Abstract
Rhomboids are intramembrane serine proteases that cleave the transmembrane helices of substrate proteins, typically releasing luminal/extracellular domains from the membrane. They are conserved in all branches of life and there is a growing recognition of their association with a wide range of human diseases. Human rhomboids, for example, have been implicated in cancer, metabolic disease and neurodegeneration, while rhomboids in apicomplexan parasites appear to contribute to their invasion of host cells. Recent advances in our knowledge of the structure and the enzyme function of rhomboids, and increasing efforts to identify specific inhibitors, are beginning to provide important insight into the prospect of rhomboids becoming future therapeutic targets. This article is part of a Special Issue entitled: Proteolysis as a Regulatory Event in Pathophysiology edited by Stefan Rose-John.
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Affiliation(s)
- Stefan Düsterhöft
- Dunn School of Pathology, University of Oxford, OX1 3RE, United Kingdom
| | - Ulrike Künzel
- Dunn School of Pathology, University of Oxford, OX1 3RE, United Kingdom
| | - Matthew Freeman
- Dunn School of Pathology, University of Oxford, OX1 3RE, United Kingdom.
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37
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Panigrahi R, Arutyunova E, Panwar P, Gimpl K, Keller S, Lemieux MJ. Reversible Unfolding of Rhomboid Intramembrane Proteases. Biophys J 2016; 110:1379-90. [PMID: 27028647 DOI: 10.1016/j.bpj.2016.01.032] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Revised: 01/18/2016] [Accepted: 01/22/2016] [Indexed: 12/20/2022] Open
Abstract
Denaturant-induced unfolding of helical membrane proteins provides insights into their mechanism of folding and domain organization, which take place in the chemically heterogeneous, anisotropic environment of a lipid membrane. Rhomboid proteases are intramembrane proteases that play key roles in various diseases. Crystal structures have revealed a compact helical bundle with a buried active site, which requires conformational changes for the cleavage of transmembrane substrates. A dimeric form of the rhomboid protease has been shown to be important for activity. In this study, we examine the mechanism of refolding for two distinct rhomboids to gain insight into their secondary structure-activity relationships. Although helicity is largely abolished in the unfolded states of both proteins, unfolding is completely reversible for HiGlpG but only partially reversible for PsAarA. Refolding of both proteins results in reassociation of the dimer, with a 90% regain of catalytic activity for HiGlpG but only a 70% regain for PsAarA. For both proteins, a broad, gradual transition from the native, folded state to the denatured, partly unfolded state was revealed with the aid of circular dichroism spectroscopy as a function of denaturant concentration, thus arguing against a classical two-state model as found for many globular soluble proteins. Thermal denaturation has irreversible destabilizing effects on both proteins, yet reveals important functional details regarding substrate accessibility to the buried active site. This concerted biophysical and functional analysis demonstrates that HiGlpG, with a simple six-transmembrane-segment organization, is more robust than PsAarA, which has seven predicted transmembrane segments, thus rendering HiGlpG amenable to in vitro studies of membrane-protein folding.
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Affiliation(s)
- Rashmi Panigrahi
- Department of Biochemistry, Membrane Protein Disease Research Group, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Elena Arutyunova
- Department of Biochemistry, Membrane Protein Disease Research Group, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Pankaj Panwar
- Department of Biochemistry, Membrane Protein Disease Research Group, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Katharina Gimpl
- Molecular Biophysics, University of Kaiserslautern, Kaiserslautern, Germany
| | - Sandro Keller
- Molecular Biophysics, University of Kaiserslautern, Kaiserslautern, Germany
| | - M Joanne Lemieux
- Department of Biochemistry, Membrane Protein Disease Research Group, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.
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38
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Bondar AN. Biophysical mechanism of rhomboid proteolysis: Setting a foundation for therapeutics. Semin Cell Dev Biol 2016; 60:46-51. [DOI: 10.1016/j.semcdb.2016.09.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2016] [Revised: 08/12/2016] [Accepted: 09/12/2016] [Indexed: 11/16/2022]
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Taylor KC, Sanders CR. Regulation of KCNQ/Kv7 family voltage-gated K + channels by lipids. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1859:586-597. [PMID: 27818172 DOI: 10.1016/j.bbamem.2016.10.023] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 10/24/2016] [Accepted: 10/31/2016] [Indexed: 12/19/2022]
Abstract
Many years of studies have established that lipids can impact membrane protein structure and function through bulk membrane effects, by direct but transient annular interactions with the bilayer-exposed surface of protein transmembrane domains, and by specific binding to protein sites. Here, we focus on how phosphatidylinositol 4,5-bisphosphate (PIP2) and polyunsaturated fatty acids (PUFAs) impact ion channel function and how the structural details of the interactions of these lipids with ion channels are beginning to emerge. We focus on the Kv7 (KCNQ) subfamily of voltage-gated K+ channels, which are regulated by both PIP2 and PUFAs and play a variety of important roles in human health and disease. This article is part of a Special Issue entitled: Lipid order/lipid defects and lipid-control of protein activity edited by Dirk Schneider.
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Affiliation(s)
- Keenan C Taylor
- Department of Biochemistry, Vanderbilt University, Nashville, TN, USA; Center for Structural Biology, Vanderbilt University, Nashville, TN, USA
| | - Charles R Sanders
- Department of Biochemistry, Vanderbilt University, Nashville, TN, USA; Center for Structural Biology, Vanderbilt University, Nashville, TN, USA; Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA.
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40
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Urban S. A guide to the rhomboid protein superfamily in development and disease. Semin Cell Dev Biol 2016; 60:1-4. [PMID: 27751777 DOI: 10.1016/j.semcdb.2016.10.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Accepted: 10/13/2016] [Indexed: 11/28/2022]
Abstract
Rhomboid proteins are considered to be the most widespread membrane proteins across all forms of life. This superfamily comprises both active intramembrane serine proteases that catalyze the release of factors from the membrane, and a eukaryotic subset of non-catalytic members in which rhomboid architecture supports deviating functions. Although rhomboid was discovered in genetic studies of insect development, rhomboid research has broadened dramatically over the past 15 years; rhomboid enzymes are now the best biophysically understood of all intramembrane proteases, and are considered promising therapeutic targets for diseases ranging from parasitic infections to Parkinsonian neurodegeneration. Perhaps the most rapid progress has come with the catalytically inert rhomboid proteins, some of which regulate protein trafficking and/or function, and their prominence is underscored by clinical mutations. Such a diverse collection of advances mark an excellent point to review the state of this vibrant area of research, not because central questions have been answered, but instead because a firm grip in key areas has been established, and the field is now poised for breakthroughs.
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Affiliation(s)
- Siniša Urban
- Department of Molecular Biology & Genetics, Johns Hopkins University School of Medicine, Room 507 PCTB, 725 North Wolfe Street, Baltimore, MD, 21205, USA.
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41
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Substrates and physiological functions of secretase rhomboid proteases. Semin Cell Dev Biol 2016; 60:10-18. [PMID: 27497690 DOI: 10.1016/j.semcdb.2016.07.033] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Revised: 07/26/2016] [Accepted: 07/31/2016] [Indexed: 02/01/2023]
Abstract
Rhomboids are conserved intramembrane serine proteases with widespread functions. They were the earliest discovered members of the wider rhomboid-like superfamily of proteases and pseudoproteases. The secretase class of rhomboid proteases, distributed through the secretory pathway, are the most numerous in eukaryotes, but our knowledge of them is limited. Here we aim to summarise all that has been published on secretase rhomboids in a concise encyclopaedia of the enzymes, their substrates, and their biological roles. We also discuss emerging themes of how these important enzymes are regulated.
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42
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Cho S, Dickey SW, Urban S. Crystal Structures and Inhibition Kinetics Reveal a Two-Stage Catalytic Mechanism with Drug Design Implications for Rhomboid Proteolysis. Mol Cell 2016; 61:329-340. [PMID: 26805573 DOI: 10.1016/j.molcel.2015.12.022] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Revised: 11/20/2015] [Accepted: 12/15/2015] [Indexed: 12/28/2022]
Abstract
Intramembrane proteases signal by releasing proteins from the membrane, but despite their importance, their enzymatic mechanisms remain obscure. We probed rhomboid proteases with reversible, mechanism-based inhibitors that allow precise kinetic analysis and faithfully mimic the transition state structurally. Unexpectedly, inhibition by peptide aldehydes is non-competitive, revealing that in the Michaelis complex, substrate does not contact the catalytic center. Structural analysis in a membrane revealed that all extracellular loops of rhomboid make stabilizing interactions with substrate, but mainly through backbone interactions, explaining rhomboid's broad sequence selectivity. At the catalytic site, the tetrahedral intermediate lies covalently attached to the catalytic serine alone, with the oxyanion stabilized by unusual tripartite interactions with the side chains of H150, N154, and the backbone of S201. We also visualized unexpected substrate-enzyme interactions at the non-essential P2/P3 residues. These "extra" interactions foster potent rhomboid inhibition in living cells, thereby opening avenues for rational design of selective rhomboid inhibitors.
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Affiliation(s)
- Sangwoo Cho
- Howard Hughes Medical Institute, Department of Molecular Biology & Genetics, Johns Hopkins University School of Medicine, Room 507 PCTB, 725 North Wolfe Street, Baltimore, Maryland, USA, 21205
| | - Seth W Dickey
- Howard Hughes Medical Institute, Department of Molecular Biology & Genetics, Johns Hopkins University School of Medicine, Room 507 PCTB, 725 North Wolfe Street, Baltimore, Maryland, USA, 21205
| | - Siniša Urban
- Howard Hughes Medical Institute, Department of Molecular Biology & Genetics, Johns Hopkins University School of Medicine, Room 507 PCTB, 725 North Wolfe Street, Baltimore, Maryland, USA, 21205
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43
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Cournia Z, Allen TW, Andricioaei I, Antonny B, Baum D, Brannigan G, Buchete NV, Deckman JT, Delemotte L, del Val C, Friedman R, Gkeka P, Hege HC, Hénin J, Kasimova MA, Kolocouris A, Klein ML, Khalid S, Lemieux MJ, Lindow N, Roy M, Selent J, Tarek M, Tofoleanu F, Vanni S, Urban S, Wales DJ, Smith JC, Bondar AN. Membrane Protein Structure, Function, and Dynamics: a Perspective from Experiments and Theory. J Membr Biol 2015; 248:611-40. [PMID: 26063070 PMCID: PMC4515176 DOI: 10.1007/s00232-015-9802-0] [Citation(s) in RCA: 130] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Accepted: 03/26/2015] [Indexed: 01/05/2023]
Abstract
Membrane proteins mediate processes that are fundamental for the flourishing of biological cells. Membrane-embedded transporters move ions and larger solutes across membranes; receptors mediate communication between the cell and its environment and membrane-embedded enzymes catalyze chemical reactions. Understanding these mechanisms of action requires knowledge of how the proteins couple to their fluid, hydrated lipid membrane environment. We present here current studies in computational and experimental membrane protein biophysics, and show how they address outstanding challenges in understanding the complex environmental effects on the structure, function, and dynamics of membrane proteins.
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Affiliation(s)
- Zoe Cournia
- Biomedical Research Foundation, Academy of Athens, 4 Soranou Ephessiou, 11527, Athens, Greece
| | - Toby W. Allen
- School of Applied Sciences & Health Innovations Research Institute, RMIT University, GPO Box 2476, Melbourne, Vic, 3001, Australia; and Department of Chemistry, University of California, Davis. Davis, CA 95616, USA
| | - Ioan Andricioaei
- Department of Chemistry, University of California, Irvine, CA 92697
| | - Bruno Antonny
- Institut de Pharmacologie Moléculaire et Cellulaire, Université de Nice Sophia-Antipolis and Centre National de la Recherche Scientifique, UMR 7275, 06560 Valbonne, France
| | - Daniel Baum
- Department of Visualization and Data Analysis, Zuse Institute Berlin, Takustrasse 7, D-14195 Berlin, Germany
| | - Grace Brannigan
- Center for Computational and Integrative Biology and Department of Physics, Rutgers University-Camden, Camden, NJ, USA
| | - Nicolae-Viorel Buchete
- School of Physics and Complex and Adaptive Systems Laboratory, University College Dublin, Belfield, Dublin 4, Ireland
| | | | - Lucie Delemotte
- Institute of Computational and Molecular Science, Temple University, Philadelphia, Pennsylvania 19122, United States
| | - Coral del Val
- Department of Artificial Intelligence, University of Granada, E-18071 Granada, Spain
| | - Ran Friedman
- Linnæus University, Department of Chemistry and Biomedical Sciences & Centre for Biomaterials Chemistry, 391 82 Kalmar, Sweden
| | - Paraskevi Gkeka
- Biomedical Research Foundation, Academy of Athens, 4 Soranou Ephessiou, 11527, Athens, Greece
| | - Hans-Christian Hege
- Department of Visualization and Data Analysis, Zuse Institute Berlin, Takustrasse 7, D-14195 Berlin, Germany
| | - Jérôme Hénin
- Laboratoire de Biochimie Théorique, IBPC and CNRS, Paris, France
| | - Marina A. Kasimova
- Université de Lorraine, SRSMC, UMR 7565, Vandoeuvre-lès-Nancy, F-54500, France
- Lomonosov Moscow State University, Moscow, 119991, Russian Federation
| | - Antonios Kolocouris
- Faculty of Pharmacy, Department of Pharmaceutical Chemistry, University of Athens, Panepistimioupolis-Zografou, 15771 Athens, Greece
| | - Michael L. Klein
- Institute of Computational and Molecular Science, Temple University, Philadelphia, Pennsylvania 19122, United States
| | - Syma Khalid
- Department of Chemistry, University of Southampton, Highfield, Southampton, SO17 1BJ, UK
| | - M. Joanne Lemieux
- Department of Biochemistry, Faculty of Medicine & Dentistry, Membrane Protein Disease Research Group, and Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada, T6G 2H7
| | - Norbert Lindow
- Department of Visualization and Data Analysis, Zuse Institute Berlin, Takustrasse 7, D-14195 Berlin, Germany
| | - Mahua Roy
- Department of Chemistry, University of California, Irvine
| | - Jana Selent
- Research Programme on Biomedical Informatics (GRIB), Department of Experimental and Health Sciences, Universitat Pompeu Fabra, IMIM (Hospital del Mar Medical Research Institute), Dr. Aiguader 88, E-08003 Barcelona, Spain
| | - Mounir Tarek
- Université de Lorraine, SRSMC, UMR 7565, Vandoeuvre-lès-Nancy, F-54500, France
- CNRS, SRSMC, UMR 7565, Vandoeuvre-lès-Nancy, F-54500, France
| | - Florentina Tofoleanu
- School of Physics and Complex and Adaptive Systems Laboratory, University College Dublin, Belfield, Dublin 4, Ireland
| | - Stefano Vanni
- Institut de Pharmacologie Moléculaire et Cellulaire, Université de Nice Sophia-Antipolis and Centre National de la Recherche Scientifique, UMR 7275, 06560 Valbonne, France
| | - Sinisa Urban
- Johns Hopkins University School of Medicine, Howard Hughes Medical Institute, Department of Molecular Biology & Genetics, 725 N. Wolfe Street, 507 Preclinical Teaching Building, Baltimore, MD 21205, USA
| | - David J. Wales
- University Chemical Laboratories, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K
| | - Jeremy C. Smith
- Oak Ridge National Laboratory, PO BOX 2008 MS6309, Oak Ridge, TN 37831-6309, USA
| | - Ana-Nicoleta Bondar
- Theoretical Molecular Biophysics, Department of Physics, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin, Germany
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Lindholm L, Ariöz C, Jawurek M, Liebau J, Mäler L, Wieslander Å, von Ballmoos C, Barth A. Effect of lipid bilayer properties on the photocycle of green proteorhodopsin. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1847:698-708. [DOI: 10.1016/j.bbabio.2015.04.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Revised: 04/17/2015] [Accepted: 04/21/2015] [Indexed: 01/20/2023]
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45
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Cytosolic extensions directly regulate a rhomboid protease by modulating substrate gating. Nature 2015; 523:101-5. [PMID: 25970241 PMCID: PMC4490020 DOI: 10.1038/nature14357] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Accepted: 03/02/2015] [Indexed: 11/15/2022]
Abstract
Intramembrane proteases catalyze the signal-generating step of various cell signaling pathways, and continue to be implicated in diseases ranging from malaria infection to Parkinsonian neurodegeneration1–3. Despite playing such decisive roles, it remains unclear whether or how these membrane-immersed enzymes might be regulated directly. To address this limitation, we sought intramembrane proteases containing domains known to exert regulatory functions in other contexts, and focused on rhomboid proteases that harbor calcium-binding EF-hands. We found calcium potently stimulates proteolysis by endogenous rhomboid-4 in Drosophila cells, and, remarkably, when rhomboid-4 was purified and reconstituted in liposomes. Interestingly, deleting the amino-terminal EF-hands activated proteolysis prematurely, while residues in cytoplasmic loops connecting distal transmembrane segments mediated calcium stimulation. Rhomboid regulation was not orchestrated by either dimerization or substrate interactions. Instead, calcium increased catalytic rate by promoting substrate gating. Substrates with cleavage sites outside the membrane could be cleaved but lost the capacity to be regulated. These observations indicate substrate gating is not an essential step in catalysis, but instead evolved as a mechanism for regulating proteolysis inside the membrane. Moreover, these insights provide new approaches for studying rhomboid functions by investigating upstream inputs that trigger proteolysis.
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Karp JM, Erylimaz E, Cowburn D. Correlation of chemical shifts predicted by molecular dynamics simulations for partially disordered proteins. JOURNAL OF BIOMOLECULAR NMR 2015; 61:35-45. [PMID: 25416617 PMCID: PMC4715900 DOI: 10.1007/s10858-014-9879-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Accepted: 11/17/2014] [Indexed: 06/04/2023]
Abstract
There has been a longstanding interest in being able to accurately predict NMR chemical shifts from structural data. Recent studies have focused on using molecular dynamics (MD) simulation data as input for improved prediction. Here we examine the accuracy of chemical shift prediction for intein systems, which have regions of intrinsic disorder. We find that using MD simulation data as input for chemical shift prediction does not consistently improve prediction accuracy over use of a static X-ray crystal structure. This appears to result from the complex conformational ensemble of the disordered protein segments. We show that using accelerated molecular dynamics (aMD) simulations improves chemical shift prediction, suggesting that methods which better sample the conformational ensemble like aMD are more appropriate tools for use in chemical shift prediction for proteins with disordered regions. Moreover, our study suggests that data accurately reflecting protein dynamics must be used as input for chemical shift prediction in order to correctly predict chemical shifts in systems with disorder.
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Affiliation(s)
- Jerome M. Karp
- Department of Biochemistry, Albert Einstein College of, Medicine of Yeshiva University, 1300 Morris Park Avenue, Bronx, NY 10461, USA
| | - Ertan Erylimaz
- Department of Biochemistry, Albert Einstein College of, Medicine of Yeshiva University, 1300 Morris Park Avenue, Bronx, NY 10461, USA
| | - David Cowburn
- Department of Biochemistry, Albert Einstein College of, Medicine of Yeshiva University, 1300 Morris Park Avenue, Bronx, NY 10461, USA
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Li Y, Bohm C, Dodd R, Chen F, Qamar S, Schmitt-Ulms G, Fraser PE, St George-Hyslop PH. Structural biology of presenilin 1 complexes. Mol Neurodegener 2014; 9:59. [PMID: 25523933 PMCID: PMC4326451 DOI: 10.1186/1750-1326-9-59] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Accepted: 12/12/2014] [Indexed: 11/17/2022] Open
Abstract
The presenilin genes were first identified as the site of missense mutations causing early onset autosomal dominant familial Alzheimer's disease. Subsequent work has shown that the presenilin proteins are the catalytic subunits of a hetero-tetrameric complex containing APH1, nicastrin and PEN-2. This complex (variously termed presenilin complex or gamma-secretase complex) performs an unusual type of proteolysis in which the transmembrane domains of Type I proteins are cleaved within the hydrophobic compartment of the membrane. This review describes some of the molecular and structural biology of this unusual enzyme complex. The presenilin complex is a bilobed structure. The head domain contains the ectodomain of nicastrin. The base domain contains a central cavity with a lateral cleft that likely provides the route for access of the substrate to the catalytic cavity within the centre of the base domain. There are reciprocal allosteric interactions between various sites in the complex that affect its function. For instance, binding of Compound E, a peptidomimetic inhibitor to the PS1 N-terminus, induces significant conformational changes that reduces substrate binding at the initial substrate docking site, and thus inhibits substrate cleavage. However, there is a reciprocal allosteric interaction between these sites such that prior binding of the substrate to the initial docking site paradoxically increases the binding of the Compound E peptidomimetic inhibitor. Such reciprocal interactions are likely to form the basis of a gating mechanism that underlies access of substrate to the catalytic site. An increasingly detailed understanding of the structural biology of the presenilin complex is an essential step towards rational design of substrate- and/or cleavage site-specific modulators of presenilin complex function.
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Affiliation(s)
| | | | | | | | | | | | | | - Peter H St George-Hyslop
- Cambridge Institute for Medical Research, Wellcome Trust MRC Building, Addenbrookes Hospital, Hills Road, Cambridge CB2 0XY, UK.
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Foo ACY, Harvey BGR, Metz JJ, Goto NK. Influence of hydrophobic mismatch on the catalytic activity of Escherichia coli GlpG rhomboid protease. Protein Sci 2014; 24:464-73. [PMID: 25307614 DOI: 10.1002/pro.2585] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Accepted: 10/09/2014] [Indexed: 12/21/2022]
Abstract
Rhomboids comprise a broad family of intramembrane serine proteases that are found in a wide range of organisms and participate in a diverse array of biological processes. High-resolution structures of the catalytic transmembrane domain of the Escherichia coli GlpG rhomboid have provided numerous insights that help explain how hydrolytic cleavage can be achieved below the membrane surface. Key to this are observations that GlpG hydrophobic domain dimensions may not be sufficient to completely span the native lipid bilayer. This formed the basis for a model where hydrophobic mismatch Induces thinning of the local membrane environment to promote access to transmembrane substrates. However, hydrophobic mismatch also has the potential to alter the functional properties of the rhomboid, a possibility we explore in the current work. For this purpose, we purified the catalytic transmembrane domain of GlpG into phosphocholine or maltoside detergent micelles of varying alkyl chain lengths, and assessed proteolytic function with a model water-soluble substrate. Catalytic turnover numbers were found to depend on detergent alkyl chain length, with saturated chains containing 10-12 carbon atoms supporting maximal activity. Similar results were obtained in phospholipid bicelles, with no proteolytic activity being detected in longer-chain lipids. Although differences in thermal stability and GlpG oligomerization could not explain these activity differences, circular dichroism spectra suggest that mismatch gives rise to a small change in structure. Overall, these results demonstrate that hydrophobic mismatch can exert an inhibitory effect on rhomboid activity, with the potential for changes in local membrane environment to regulate activity in vivo.
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Affiliation(s)
- Alexander C Y Foo
- Department of Chemistry, University of Ottawa, Ottawa, Ontario, Canada, K1N 6N5
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Zattas D, Hochstrasser M. Ubiquitin-dependent protein degradation at the yeast endoplasmic reticulum and nuclear envelope. Crit Rev Biochem Mol Biol 2014; 50:1-17. [PMID: 25231236 DOI: 10.3109/10409238.2014.959889] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The endoplasmic reticulum (ER) is the primary organelle in eukaryotic cells where membrane and secreted proteins are inserted into or across cell membranes. Its membrane bilayer and luminal compartments provide a favorable environment for the folding and assembly of thousands of newly synthesized proteins. However, protein folding is intrinsically error-prone, and various stress conditions can further increase levels of protein misfolding and damage, particularly in the ER, which can lead to cellular dysfunction and disease. The ubiquitin-proteasome system (UPS) is responsible for the selective destruction of a vast array of protein substrates, either for protein quality control or to allow rapid changes in the levels of specific regulatory proteins. In this review, we will focus on the components and mechanisms of ER-associated protein degradation (ERAD), an important branch of the UPS. ER membranes extend from subcortical regions of the cell to the nuclear envelope, with its continuous outer and inner membranes; the nuclear envelope is a specialized subdomain of the ER. ERAD presents additional challenges to the UPS beyond those faced with soluble substrates of the cytoplasm and nucleus. These include recognition of sugar modifications that occur in the ER, retrotranslocation of proteins across the membrane bilayer, and transfer of substrates from the ER extraction machinery to the proteasome. Here, we review characteristics of ERAD substrate degradation signals (degrons), mechanisms underlying substrate recognition and processing by the ERAD machinery, and ideas on the still unresolved problem of how substrate proteins are moved across and extracted from the ER membrane.
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Affiliation(s)
- Dimitrios Zattas
- Department of Molecular Biophysics & Biochemistry, Yale University , New Haven, CT , USA
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Zoll S, Stanchev S, Began J, Skerle J, Lepšík M, Peclinovská L, Majer P, Strisovsky K. Substrate binding and specificity of rhomboid intramembrane protease revealed by substrate-peptide complex structures. EMBO J 2014; 33:2408-21. [PMID: 25216680 PMCID: PMC4253528 DOI: 10.15252/embj.201489367] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The mechanisms of intramembrane proteases are incompletely understood due to the lack of structural data on substrate complexes. To gain insight into substrate binding by rhomboid proteases, we have synthesised a series of novel peptidyl-chloromethylketone (CMK) inhibitors and analysed their interactions with Escherichia coli rhomboid GlpG enzymologically and structurally. We show that peptidyl-CMKs derived from the natural rhomboid substrate TatA from bacterium Providencia stuartii bind GlpG in a substrate-like manner, and their co-crystal structures with GlpG reveal the S1 to S4 subsites of the protease. The S1 subsite is prominent and merges into the 'water retention site', suggesting intimate interplay between substrate binding, specificity and catalysis. Unexpectedly, the S4 subsite is plastically formed by residues of the L1 loop, an important but hitherto enigmatic feature of the rhomboid fold. We propose that the homologous region of members of the wider rhomboid-like protein superfamily may have similar substrate or client-protein binding function. Finally, using molecular dynamics, we generate a model of the Michaelis complex of the substrate bound in the active site of GlpG.
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Affiliation(s)
- Sebastian Zoll
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Stancho Stanchev
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Jakub Began
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic Department of Microbiology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Jan Skerle
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic Department of Biochemistry, Faculty of Science, Charles University, Prague, Czech Republic
| | - Martin Lepšík
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Lucie Peclinovská
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic Department of Biochemistry, Faculty of Science, Charles University, Prague, Czech Republic
| | - Pavel Majer
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Kvido Strisovsky
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic
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