1
|
Shi L, Yang C, Zhang M, Li K, Wang K, Jiao L, Liu R, Wang Y, Li M, Wang Y, Ma L, Hu S, Bian X. Dissecting the mechanism of atlastin-mediated homotypic membrane fusion at the single-molecule level. Nat Commun 2024; 15:2488. [PMID: 38509071 PMCID: PMC10954664 DOI: 10.1038/s41467-024-46919-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 03/13/2024] [Indexed: 03/22/2024] Open
Abstract
Homotypic membrane fusion of the endoplasmic reticulum (ER) is mediated by dynamin-like GTPase atlastin (ATL). This fundamental process relies on GTP-dependent domain rearrangements in the N-terminal region of ATL (ATLcyto), including the GTPase domain and three-helix bundle (3HB). However, its conformational dynamics during the GTPase cycle remain elusive. Here, we combine single-molecule FRET imaging and molecular dynamics simulations to address this conundrum. Different from the prevailing model, ATLcyto can form a loose crossover dimer upon GTP binding, which is tightened by GTP hydrolysis for membrane fusion. Furthermore, the α-helical motif between the 3HB and transmembrane domain, which is embedded in the surface of the lipid bilayer and self-associates in the crossover dimer, is required for ATL function. To recycle the proteins, Pi release, which disassembles the dimer, activates frequent relative movements between the GTPase domain and 3HB, and subsequent GDP dissociation alters the conformational preference of the ATLcyto monomer for entering the next reaction cycle. Finally, we found that two disease-causing mutations affect human ATL1 activity by destabilizing GTP binding-induced loose crossover dimer formation and the membrane-embedded helix, respectively. These results provide insights into ATL-mediated homotypic membrane fusion and the pathological mechanisms of related disease.
Collapse
Affiliation(s)
- Lijun Shi
- State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Frontiers Science Center for Cell Responses, Nankai University, Tianjin, 300071, China
| | - Chenguang Yang
- National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Mingyuan Zhang
- College of Life Sciences, Zhejiang University, Hangzhou, 310027, China
| | - Kangning Li
- State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Frontiers Science Center for Cell Responses, Nankai University, Tianjin, 300071, China
| | - Keying Wang
- College of Life Sciences, Zhejiang University, Hangzhou, 310027, China
| | - Li Jiao
- College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Ruming Liu
- College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Yunyun Wang
- State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Frontiers Science Center for Cell Responses, Nankai University, Tianjin, 300071, China
| | - Ming Li
- National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Yong Wang
- College of Life Sciences, Zhejiang University, Hangzhou, 310027, China.
- The Provincial International Science and Technology Cooperation Base on Engineering Biology, International Campus of Zhejiang University, Haining, 314400, China.
| | - Lu Ma
- National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.
| | - Shuxin Hu
- National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.
| | - Xin Bian
- State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Frontiers Science Center for Cell Responses, Nankai University, Tianjin, 300071, China.
| |
Collapse
|
2
|
Schumann W, Loschwitz J, Reiners J, Degrandi D, Legewie L, Stühler K, Pfeffer K, Poschmann G, Smits SHJ, Strodel B. Integrative modeling of guanylate binding protein dimers. Protein Sci 2023; 32:e4818. [PMID: 37916607 PMCID: PMC10683561 DOI: 10.1002/pro.4818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 09/27/2023] [Accepted: 09/30/2023] [Indexed: 11/03/2023]
Abstract
Guanylate-binding proteins (GBPs) are essential interferon-γ-activated large GTPases that play a crucial role in host defense against intracellular bacteria and parasites. While their protective functions rely on protein polymerization, our understanding of the structural intricacies of these multimerized states remains limited. To bridge this knowledge gap, we present dimer models for human GBP1 (hGBP1) and murine GBP2 and 7 (mGBP2 and mGBP7) using an integrative approach, incorporating the crystal structure of hGBP1's GTPase domain dimer, crosslinking mass spectrometry, small-angle X-ray scattering, protein-protein docking, and molecular dynamics simulations. Our investigation begins by comparing the protein dynamics of hGBP1, mGBP2, and mGBP7. We observe that the M/E domain in all three proteins exhibits significant mobility and hinge motion, with mGBP7 displaying a slightly less pronounced motion but greater flexibility in its GTPase domain. These dynamic distinctions can be attributed to variations in the sequences of mGBP7 and hGBP1/mGBP2, resulting in different dimerization modes. Unlike hGBP1 and its close ortholog mGBP2, which exclusively dimerize through their GTPase domains, we find that mGBP7 exhibits three equally probable alternative dimer structures. The GTPase domain of mGBP7 is only partially involved in its dimerization, primarily due to an accumulation of negative charge, allowing mGBP7 to dimerize independently of GTP. Instead, mGBP7 exhibits a strong tendency to dimerize in an antiparallel arrangement across its stalks. The results of this work go beyond the sequence-structure-function relationship, as the sequence differences in mGBP7 and mGBP2/hGBP1 do not lead to different structures, but to different protein dynamics and dimerization. The distinct GBP dimer structures are expected to encode specific functions crucial for disrupting pathogen membranes.
Collapse
Affiliation(s)
- Wibke Schumann
- Institute of Theoretical and Computational ChemistryHeinrich Heine University DüsseldorfDüsseldorfGermany
- Institute of Biological Information Processing: Structural BiochemistryForschungszentrum JülichJülichGermany
| | - Jennifer Loschwitz
- Institute of Theoretical and Computational ChemistryHeinrich Heine University DüsseldorfDüsseldorfGermany
- Institute of Biological Information Processing: Structural BiochemistryForschungszentrum JülichJülichGermany
| | - Jens Reiners
- Center for Structural StudiesHeinrich Heine University DüsseldorfDüsseldorfGermany
| | - Daniel Degrandi
- Institute of Medical Microbiology and Hospital HygieneHeinrich Heine UniversityDüsseldorfGermany
| | - Larissa Legewie
- Institute of Medical Microbiology and Hospital HygieneHeinrich Heine UniversityDüsseldorfGermany
| | - Kai Stühler
- Institute of Molecular Medicine, Proteome ResearchMedical Faculty and University Hospital Düsseldorf, Heinrich Heine University DüsseldorfDüsseldorfGermany
- Molecular Proteomics Laboratory, Biomedical Research Centre (BMFZ)Heinrich Heine University DüsseldorfDüsseldorfGermany
| | - Klaus Pfeffer
- Institute of Medical Microbiology and Hospital HygieneHeinrich Heine UniversityDüsseldorfGermany
| | - Gereon Poschmann
- Institute of Molecular Medicine, Proteome ResearchMedical Faculty and University Hospital Düsseldorf, Heinrich Heine University DüsseldorfDüsseldorfGermany
| | - Sander H. J. Smits
- Center for Structural StudiesHeinrich Heine University DüsseldorfDüsseldorfGermany
- Institute for BiochemistryHeinrich Heine University DüsseldorfDüsseldorfGermany
| | - Birgit Strodel
- Institute of Theoretical and Computational ChemistryHeinrich Heine University DüsseldorfDüsseldorfGermany
- Institute of Biological Information Processing: Structural BiochemistryForschungszentrum JülichJülichGermany
| |
Collapse
|
3
|
Das AK, Mandal AK, Mondal T. Probing Single-molecule Interfacial Electron Transfer Inside a Single Lipid Vesicle. J Fluoresc 2023; 33:2229-2239. [PMID: 37004622 DOI: 10.1007/s10895-023-03211-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Accepted: 03/13/2023] [Indexed: 04/04/2023]
Abstract
Inhomogeneity in single molecule electron transfer at the surface of lipid in a single vesicle has been explored by single molecule spectroscopic technique. In our study we took Di-methyl aniline (DMA), as the electron donor (D) and three different organic dyes as acceptor. These dyes are C153, C480 and C152 and they reside in different regions in the vesicle depending upon their preference of residence. For each probe, we found fluctuations in the single-molecule fluorescence decay, which are attributed to the variation in the reactivity of interfacial electron transfer. We found a non-exponential auto-correlation fluctuation of the intensity of the probe, which is ascribed to the kinetic disorder in the rate of electron transfer. We have also shown the power law distribution of the dark state (off time), which obeys the levy's statistics. We found a shift in lifetime distribution for the probe (C153) from 3.9 ns to 3.5 ns. This observed quenching is due to the dynamic electron transfer. We observed the kinetic disorderness in the electron transfer reaction for each dye. This source of fluctuation in electron transfer rate may be ascribed to the inherent fluctuation, occurring on the time scale of ~ 1.1 ms (for C153) of the vesicle, containing lipids.
Collapse
Affiliation(s)
- Atanu Kumar Das
- Department of Physics, Kandi Raj College, Murshidabad, West Bengal, 742137, India
| | - Amit Kumar Mandal
- Department of Chemistry, Bankura University, Bankura, West Bengal, 722155, India
| | - Tridib Mondal
- Department of Chemistry, Sukanta Mahavidyalaya, Jalpaiguri, West Bengal, 735210, India.
| |
Collapse
|
4
|
Loschwitz J, Steffens N, Wang X, Schäffler M, Pfeffer K, Degrandi D, Strodel B. Domain motions, dimerization, and membrane interactions of the murine guanylate binding protein 2. Sci Rep 2023; 13:679. [PMID: 36639389 PMCID: PMC9839784 DOI: 10.1038/s41598-023-27520-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 01/03/2023] [Indexed: 01/15/2023] Open
Abstract
Guanylate-binding proteins (GBPs) are a group of GTPases that are induced by interferon-[Formula: see text] and are crucial components of cell-autonomous immunity against intracellular pathogens. Here, we examine murine GBP2 (mGBP2), which we have previously shown to be an essential effector protein for the control of Toxoplasma gondii replication, with its recruitment through the membrane of the parasitophorous vacuole and its involvement in the destruction of this membrane likely playing a role. The overall aim of our work is to provide a molecular-level understanding of the mutual influences of mGBP2 and the parasitophorous vacuole membrane. To this end, we performed lipid-binding assays which revealed that mGBP2 has a particular affinity for cardiolipin. This observation was confirmed by fluorescence microscopy using giant unilamellar vesicles of different lipid compositions. To obtain an understanding of the protein dynamics and how this is affected by GTP binding, mGBP2 dimerization, and membrane binding, assuming that each of these steps are relevant for the function of the protein, we carried out standard as well as replica exchange molecular dynamics simulations with an accumulated simulation time of more than 30 μs. The main findings from these simulations are that mGBP2 features a large-scale hinge motion in its M/E domain, which is present in each of the studied protein states. When bound to a cardiolipin-containing membrane, this hinge motion is particularly pronounced, leading to an up and down motion of the M/E domain on the membrane, which did not occur on a membrane without cardiolipin. Our prognosis is that this up and down motion has the potential to destroy the membrane following the formation of supramolecular mGBP2 complexes on the membrane surface.
Collapse
Affiliation(s)
- Jennifer Loschwitz
- grid.411327.20000 0001 2176 9917Institute of Theoretical and Computational Chemistry, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany ,grid.8385.60000 0001 2297 375XInstitute of Biological Information Processing: Structural Biochemistry (IBI-7), Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Nora Steffens
- grid.411327.20000 0001 2176 9917Institute of Medical Microbiology and Hospital Hygiene, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Xue Wang
- grid.411327.20000 0001 2176 9917Institute of Theoretical and Computational Chemistry, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany ,grid.8385.60000 0001 2297 375XInstitute of Biological Information Processing: Structural Biochemistry (IBI-7), Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Moritz Schäffler
- grid.8385.60000 0001 2297 375XInstitute of Biological Information Processing: Structural Biochemistry (IBI-7), Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Klaus Pfeffer
- grid.411327.20000 0001 2176 9917Institute of Medical Microbiology and Hospital Hygiene, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Daniel Degrandi
- Institute of Medical Microbiology and Hospital Hygiene, Heinrich Heine University Düsseldorf, Düsseldorf, Germany.
| | - Birgit Strodel
- Institute of Theoretical and Computational Chemistry, Heinrich Heine University Düsseldorf, 40225, Düsseldorf, Germany. .,Institute of Biological Information Processing: Structural Biochemistry (IBI-7), Forschungszentrum Jülich, 52425, Jülich, Germany.
| |
Collapse
|
5
|
Serrero MC, Girault V, Weigang S, Greco TM, Ramos-Nascimento A, Anderson F, Piras A, Hickford Martinez A, Hertzog J, Binz A, Pohlmann A, Prank U, Rehwinkel J, Bauerfeind R, Cristea IM, Pichlmair A, Kochs G, Sodeik B. The interferon-inducible GTPase MxB promotes capsid disassembly and genome release of herpesviruses. eLife 2022; 11:e76804. [PMID: 35475759 PMCID: PMC9150894 DOI: 10.7554/elife.76804] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 04/22/2022] [Indexed: 11/18/2022] Open
Abstract
Host proteins sense viral products and induce defence mechanisms, particularly in immune cells. Using cell-free assays and quantitative mass spectrometry, we determined the interactome of capsid-host protein complexes of herpes simplex virus and identified the large dynamin-like GTPase myxovirus resistance protein B (MxB) as an interferon-inducible protein interacting with capsids. Electron microscopy analyses showed that cytosols containing MxB had the remarkable capability to disassemble the icosahedral capsids of herpes simplex viruses and varicella zoster virus into flat sheets of connected triangular faces. In contrast, capsids remained intact in cytosols with MxB mutants unable to hydrolyse GTP or to dimerize. Our data suggest that MxB senses herpesviral capsids, mediates their disassembly, and thereby restricts the efficiency of nuclear targeting of incoming capsids and/or the assembly of progeny capsids. The resulting premature release of viral genomes from capsids may enhance the activation of DNA sensors, and thereby amplify the innate immune responses.
Collapse
Affiliation(s)
- Manutea C Serrero
- Institute of Virology, Hannover Medical SchoolHannoverGermany
- RESIST - Cluster of Excellence, Hannover Medical SchoolHannoverGermany
| | | | - Sebastian Weigang
- Institute of Virology, Freiburg University Medical Center, University of FreiburgFreiburgGermany
| | - Todd M Greco
- Department of Molecular Biology, Princeton UniversityPrincetonUnited States
| | | | - Fenja Anderson
- Institute of Virology, Hannover Medical SchoolHannoverGermany
| | - Antonio Piras
- Institute of Virology, Technical University MunichMunichGermany
| | | | - Jonny Hertzog
- MRC Human Immunology Unit, MRC Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of OxfordOxfordUnited Kingdom
| | - Anne Binz
- Institute of Virology, Hannover Medical SchoolHannoverGermany
- RESIST - Cluster of Excellence, Hannover Medical SchoolHannoverGermany
- German Center for Infection Research (DZIF), Hannover-Braunschweig Partner SiteHannoverGermany
| | - Anja Pohlmann
- Institute of Virology, Hannover Medical SchoolHannoverGermany
- RESIST - Cluster of Excellence, Hannover Medical SchoolHannoverGermany
- German Center for Infection Research (DZIF), Hannover-Braunschweig Partner SiteHannoverGermany
| | - Ute Prank
- Institute of Virology, Hannover Medical SchoolHannoverGermany
| | - Jan Rehwinkel
- MRC Human Immunology Unit, MRC Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of OxfordOxfordUnited Kingdom
| | - Rudolf Bauerfeind
- Research Core Unit Laser Microscopy, Hannover Medical SchoolHannoverGermany
| | - Ileana M Cristea
- Department of Molecular Biology, Princeton UniversityPrincetonUnited States
| | - Andreas Pichlmair
- Institute of Virology, Technical University MunichMunichGermany
- German Center for Infection Research (DZIF), Munich Partner siteMunichGermany
| | - Georg Kochs
- Institute of Virology, Freiburg University Medical Center, University of FreiburgFreiburgGermany
| | - Beate Sodeik
- Institute of Virology, Hannover Medical SchoolHannoverGermany
- RESIST - Cluster of Excellence, Hannover Medical SchoolHannoverGermany
- German Center for Infection Research (DZIF), Hannover-Braunschweig Partner SiteHannoverGermany
| |
Collapse
|
6
|
Genomic and Phenotypic Characterization of Experimentally Selected Resistant Leishmania donovani Reveals a Role for Dynamin-1-Like Protein in the Mechanism of Resistance to a Novel Antileishmanial Compound. mBio 2022; 13:e0326421. [PMID: 35012338 PMCID: PMC8749414 DOI: 10.1128/mbio.03264-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
The implementation of prospective drug resistance (DR) studies in the research-and-development (R&D) pipeline is a common practice for many infectious diseases but not for neglected tropical diseases (NTDs). Here, we explored and demonstrated the importance of this approach using as paradigms Leishmania donovani, the etiological agent of visceral leishmaniasis (VL), and TCMDC-143345, a promising compound of the GlaxoSmithKline (GSK) "Leishbox" to treat VL. We experimentally selected resistance to TCMDC-143345 in vitro and characterized resistant parasites at the genomic and phenotypic levels. We found that it took more time to develop resistance to TCMDC-143345 than to other drugs in clinical use and that there was no cross-resistance to these drugs, suggesting a new and unique mechanism. By whole-genome sequencing, we found two mutations in the gene encoding the L. donovani dynamin-1-like protein (LdoDLP1) that were fixed at the highest drug pressure. Through phylogenetic analysis, we identified LdoDLP1 as a family member of the dynamin-related proteins, a group of proteins that impacts the shapes of biological membranes by mediating fusion and fission events, with a putative role in mitochondrial fission. We found that L. donovani lines genetically engineered to harbor the two identified LdoDLP1 mutations were resistant to TCMDC-143345 and displayed altered mitochondrial properties. By homology modeling, we showed how the two LdoDLP1 mutations may influence protein structure and function. Taken together, our data reveal a clear involvement of LdoDLP1 in the adaptation/reduced susceptibility of L. donovani to TCMDC-143345. IMPORTANCE Humans and their pathogens are continuously locked in a molecular arms race during which the eventual emergence of pathogen drug resistance (DR) seems inevitable. For neglected tropical diseases (NTDs), DR is generally studied retrospectively once it has already been established in clinical settings. We previously recommended to keep one step ahead in the host-pathogen arms race and implement prospective DR studies in the R&D pipeline, a common practice for many infectious diseases but not for NTDs. Here, using Leishmania donovani, the etiological agent of visceral leishmaniasis (VL), and TCMDC-143345, a promising compound of the GSK Leishbox to treat VL, as paradigms, we experimentally selected resistance to the compound and proceeded to genomic and phenotypic characterization of DR parasites. The results gathered in the present study suggest a new DR mechanism involving the L. donovani dynamin-1-like protein (LdoDLP1) and demonstrate the practical relevance of prospective DR studies.
Collapse
|
7
|
Quantification and demonstration of the collective constriction-by-ratchet mechanism in the dynamin molecular motor. Proc Natl Acad Sci U S A 2021; 118:2101144118. [PMID: 34244431 PMCID: PMC8285958 DOI: 10.1073/pnas.2101144118] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Dynamin is a protein that is a central player in endocytosis, a process that mediates the entry of diverse particles into cells, from nutrients to viruses. Dynamin’s primary activity is to use guanosine triphosphate as fuel to constrict and cut membrane tubes. Key quantitative aspects of its function remain yet unclear. In this work, we determine the strength of an individual dynamin motor. Then, by building a detailed computational model resolving individual motors, we demonstrate that dynamin produces sufficient force to tightly constrict a membrane tube when most of its motors are simultaneously cooperating. Hence, we quantitatively validate the prevailing constriction-by-ratchet model for nature’s strongest torque-generating motor: the dynamin “nanomuscle.” Dynamin oligomerizes into helical filaments on tubular membrane templates and, through constriction, cleaves them in a GTPase-driven way. Structural observations of GTP-dependent cross-bridges between neighboring filament turns have led to the suggestion that dynamin operates as a molecular ratchet motor. However, the proof of such mechanism remains absent. Particularly, it is not known whether a powerful enough stroke is produced and how the motor modules would cooperate in the constriction process. Here, we characterized the dynamin motor modules by single-molecule Förster resonance energy transfer (smFRET) and found strong nucleotide-dependent conformational preferences. Integrating smFRET with molecular dynamics simulations allowed us to estimate the forces generated in a power stroke. Subsequently, the quantitative force data and the measured kinetics of the GTPase cycle were incorporated into a model including both a dynamin filament, with explicit motor cross-bridges, and a realistic deformable membrane template. In our simulations, collective constriction of the membrane by dynamin motor modules, based on the ratchet mechanism, is directly reproduced and analyzed. Functional parallels between the dynamin system and actomyosin in the muscle are seen. Through concerted action of the motors, tight membrane constriction to the hemifission radius can be reached. Our experimental and computational study provides an example of how collective motor action in megadalton molecular assemblies can be approached and explicitly resolved.
Collapse
|
8
|
Gao S, Hu J. Mitochondrial Fusion: The Machineries In and Out. Trends Cell Biol 2020; 31:62-74. [PMID: 33092941 DOI: 10.1016/j.tcb.2020.09.008] [Citation(s) in RCA: 164] [Impact Index Per Article: 41.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 09/10/2020] [Accepted: 09/14/2020] [Indexed: 11/15/2022]
Abstract
Mitochondria are highly dynamic organelles that constantly undergo fission and fusion. Disruption of mitochondrial dynamics undermines their function and causes several human diseases. The fusion of the outer (OMM) and inner mitochondrial membranes (IMM) is mediated by two classes of dynamin-like protein (DLP): mitofusin (MFN)/fuzzy onions 1 (Fzo1) and optic atrophy 1/mitochondria genome maintenance 1 (OPA1/Mgm1). Given the lack of structural information on these fusogens, the molecular mechanisms underlying mitochondrial fusion remain unclear, even after 20 years. Here, we review recent advances in structural studies of the mitochondrial fusion machinery, discuss their implication for DLPs, and summarize the pathogenic mechanisms of disease-causing mutations in mitochondrial fusion DLPs.
Collapse
Affiliation(s)
- Song Gao
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, 510060 Guangzhou, China; Guangzhou Regenerative Medicine and Health Guangdong Laboratory, 510530 Guangzhou, China.
| | - Junjie Hu
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
| |
Collapse
|
9
|
Gosu V, Shin D, Song KD, Heo J, Oh JD. Molecular modeling and dynamic simulation of chicken Mx protein with the S631N polymorphism. J Biomol Struct Dyn 2020; 40:612-621. [PMID: 32962555 DOI: 10.1080/07391102.2020.1819419] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Myxovirus resistance (Mx) proteins are antiviral GTPases induced by type I interferons (IFNs). In chickens, a single Mx protein variant, S631N, has been suggested to possess antiviral activity. However, the impact of this variant on chicken Mx (chMx) protein structure and conformation has not been investigated. Hence, in this study, we applied computational methods such as molecular modeling, molecular dynamic simulation, inter domain motion and residue networks to examine the structure and dynamic behavior of wild-type and mutant chMx. At first, we built 3-dimensional structural models for both wild-type and mutant chMx proteins, which revealed that the structural organization of chMx was similar to that of human Mx proteins. Subsequently, molecular dynamics simulations revealed that angle variation around the hinge1 region led to the different stalk domain conformations between the wild-type and mutant chMx proteins. Domain motion analysis further suggested that the conformational differences in the loop region surrounded by the mutant residue may lead to an inclined stalk domain conformation in the mutant compared to the wild-type protein. In addition, we performed betweenness centrality analysis from residue interaction networks, to identify the crucial residues for intramolecular signal flow in chMx. The results of this study provided information on the differences in structure and dynamics between wild-type and mutant chMx, which may aid in understanding the structural features of the S631N mutant, that may be associated with chMx protein antiviral activity.Communicated by Ramaswamy H. Sarma.
Collapse
Affiliation(s)
- Vijayakumar Gosu
- Department of Animal Biotechnology, Jeonbuk National University, Jeonju, Republic of Korea
| | - Donghyun Shin
- The Animal Molecular Genetics and Breeding Center, Jeonbuk National University, Jeonju, Republic of Korea.,Department of Agricultural Convergence Technology, Jeonbuk National University, Jeonju, Republic of Korea
| | - Ki-Duk Song
- Department of Animal Biotechnology, Jeonbuk National University, Jeonju, Republic of Korea.,The Animal Molecular Genetics and Breeding Center, Jeonbuk National University, Jeonju, Republic of Korea.,Department of Agricultural Convergence Technology, Jeonbuk National University, Jeonju, Republic of Korea
| | - Jaeyoung Heo
- International Agricultural Development and Cooperation Center, Jeonbuk National University, Jeonju, Republic of Korea
| | - Jae-Don Oh
- Department of Animal Biotechnology, Jeonbuk National University, Jeonju, Republic of Korea
| |
Collapse
|
10
|
GTPase Activity of MxB Contributes to Its Nuclear Location, Interaction with Nucleoporins and Anti-HIV-1 Activity. Virol Sin 2020; 36:85-94. [PMID: 32632818 DOI: 10.1007/s12250-020-00249-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2020] [Accepted: 04/27/2020] [Indexed: 12/17/2022] Open
Abstract
The human myxovirus resistance 2 (Mx2/MxB) protein, a member of interferon (IFN)-inducible dynamin-like large GTPases, restricts a number of virus infections. Inhibition of these viruses occurs at poorly-defined steps after viral entry and has a common requirement for MxB oligomerization. However, the GTPase activity is essential for the anti-viral effects of MxB against herpesviruses and HBV but not HIV-1. To understand the role of MxB GTPase activity, including GTP binding and GTP hydrolysis, in restriction of HIV-1 infection, we genetically separated these two functions and evaluated their contributions to restriction. We found that both the GTP binding and hydrolysis function of MxB involved in the restriction of HIV-1 replication. The GTPase activity of MxB contributed to its nuclear location, interaction with nucleoporins (NUPs) and HIV-1 capsids. Furthermore, MxB disrupted the association between NUPs and HIV-1 cores dependently upon its GTPase activity. The function of GTPase activity was therefore multi-faceted, led to fundamentally distinct mechanisms employed by wild-type MxB and GTPase activity defective MxB mutations to restrict HIV-1 replication.
Collapse
|
11
|
Chen J, Wu Y, Wu XD, Zhou J, Liang XD, Baloch AS, Qiu YF, Gao S, Zhou B. The R614E mutation of mouse Mx1 protein contributes to the novel antiviral activity against classical swine fever virus. Vet Microbiol 2020; 243:108621. [PMID: 32273007 DOI: 10.1016/j.vetmic.2020.108621] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 02/24/2020] [Accepted: 02/24/2020] [Indexed: 01/07/2023]
Abstract
Mx proteins are interferon-induced GTPases that have broad antiviral activity against a wide range of RNA and DNA viruses. We previously demonstrated that porcine Mx1 protein (poMx1) inhibited the replication of classical swine fever virus (CSFV), an economically important Pestivirus, and that mouse Mx1 did so as well. It is unknown why the nucleus-localizing mouse Mx1 inhibits CSFV replication which occurs in the cytoplasm. To the end, we assessed the anti-CSFV actions of wild type mouse Mx1 and seven previously reported mutants (K49A, G83R, A222V, A516V, G540E, R614E and ΔL4) and identified the molecular mechanism of R614E action against CSFV replication. A series of experiments revealed that mmMx1 (R614E) mutant reposted to the cytoplasm and interacted with the CSFV nucleocapsid protein (Core), thereby inhibiting viral replication. These findings broaden our understanding of the function of Mx protein family members against CSFV and suggest that the relative conservation of Mx1 among species is the basis of broad-spectrum antiviral properties.
Collapse
Affiliation(s)
- Jing Chen
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China
| | - Yue Wu
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China
| | - Xu-Dan Wu
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China
| | - Jing Zhou
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China
| | - Xiao-Dong Liang
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China
| | - Abdul Sattar Baloch
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China
| | - Ya-Feng Qiu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, China
| | - Song Gao
- the Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, and Collaborative Innovation Center for Cancer Medicine, Guangzhou, 510060, China
| | - Bin Zhou
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China.
| |
Collapse
|
12
|
Haller O, Kochs G. Mx genes: host determinants controlling influenza virus infection and trans-species transmission. Hum Genet 2019; 139:695-705. [PMID: 31773252 PMCID: PMC7087808 DOI: 10.1007/s00439-019-02092-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 11/19/2019] [Indexed: 12/13/2022]
Abstract
The human MxA protein, encoded by the interferon-inducible MX1 gene, is an intracellular influenza A virus (IAV) restriction factor. It can protect transgenic mice from severe IAV-induced disease, indicating a key role of human MxA for host survival and suggesting that natural variations in MX1 may account for inter-individual differences in disease severity among humans. MxA also provides a robust barrier against zoonotic transmissions of avian and swine IAV strains. Therefore, zoonotic IAV must acquire MxA escape mutations to achieve sustained human-to-human transmission. Here, we discuss recent progress in the field.
Collapse
Affiliation(s)
- Otto Haller
- Institute of Virology, Medical Center, University of Freiburg, Freiburg, Germany. .,Faculty of Medicine, University of Freiburg, Freiburg, Germany. .,Institute of Molecular Life Sciences, University of Zurich, Zurich, Switzerland.
| | - Georg Kochs
- Institute of Virology, Medical Center, University of Freiburg, Freiburg, Germany.,Faculty of Medicine, University of Freiburg, Freiburg, Germany
| |
Collapse
|
13
|
Li YJ, Cao YL, Feng JX, Qi Y, Meng S, Yang JF, Zhong YT, Kang S, Chen X, Lan L, Luo L, Yu B, Chen S, Chan DC, Hu J, Gao S. Structural insights of human mitofusin-2 into mitochondrial fusion and CMT2A onset. Nat Commun 2019; 10:4914. [PMID: 31664033 PMCID: PMC6820788 DOI: 10.1038/s41467-019-12912-0] [Citation(s) in RCA: 92] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 10/02/2019] [Indexed: 01/21/2023] Open
Abstract
Mitofusin-2 (MFN2) is a dynamin-like GTPase that plays a central role in regulating mitochondrial fusion and cell metabolism. Mutations in MFN2 cause the neurodegenerative disease Charcot-Marie-Tooth type 2A (CMT2A). The molecular basis underlying the physiological and pathological relevance of MFN2 is unclear. Here, we present crystal structures of truncated human MFN2 in different nucleotide-loading states. Unlike other dynamin superfamily members including MFN1, MFN2 forms sustained dimers even after GTP hydrolysis via the GTPase domain (G) interface, which accounts for its high membrane-tethering efficiency. The biochemical discrepancy between human MFN2 and MFN1 largely derives from a primate-only single amino acid variance. MFN2 and MFN1 can form heterodimers via the G interface in a nucleotide-dependent manner. CMT2A-related mutations, mapping to different functional zones of MFN2, lead to changes in GTP hydrolysis and homo/hetero-association ability. Our study provides fundamental insight into how mitofusins mediate mitochondrial fusion and the ways their disruptions cause disease.
Collapse
Affiliation(s)
- Yu-Jie Li
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, 510060, Guangzhou, China
| | - Yu-Lu Cao
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, 510060, Guangzhou, China
| | - Jian-Xiong Feng
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, 510060, Guangzhou, China
| | - Yuanbo Qi
- Department of Genetics and Cell Biology, College of Life Sciences, Nankai University, 300071, Tianjin, China
| | - Shuxia Meng
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Jie-Feng Yang
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, 510060, Guangzhou, China
| | - Ya-Ting Zhong
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, 510060, Guangzhou, China
| | - Sisi Kang
- Department of Experimental Medicine, Guangdong Provincial Key Laboratory of Biomedical Imaging, The Fifth affiliated Hospital, Sun Yat-sen University, 519000, Zhuhai, China
| | - Xiaoxue Chen
- Department of Experimental Medicine, Guangdong Provincial Key Laboratory of Biomedical Imaging, The Fifth affiliated Hospital, Sun Yat-sen University, 519000, Zhuhai, China
| | - Lan Lan
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 100101, Beijing, China
- University of Chinese Academy of Sciences, 100101, Beijing, China
| | - Li Luo
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, 510060, Guangzhou, China
| | - Bing Yu
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, 510060, Guangzhou, China
| | - Shoudeng Chen
- Department of Experimental Medicine, Guangdong Provincial Key Laboratory of Biomedical Imaging, The Fifth affiliated Hospital, Sun Yat-sen University, 519000, Zhuhai, China
| | - David C Chan
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Junjie Hu
- Department of Genetics and Cell Biology, College of Life Sciences, Nankai University, 300071, Tianjin, China
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 100101, Beijing, China
- University of Chinese Academy of Sciences, 100101, Beijing, China
| | - Song Gao
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, 510060, Guangzhou, China.
- Guangzhou Regenerative Medicine and Health Guangdong Laboratory, 510530, Guangzhou, China.
| |
Collapse
|
14
|
Barz B, Loschwitz J, Strodel B. Large-scale, dynamin-like motions of the human guanylate binding protein 1 revealed by multi-resolution simulations. PLoS Comput Biol 2019; 15:e1007193. [PMID: 31589600 PMCID: PMC6797221 DOI: 10.1371/journal.pcbi.1007193] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 10/17/2019] [Accepted: 08/15/2019] [Indexed: 12/23/2022] Open
Abstract
Guanylate binding proteins (GBPs) belong to the dynamin-related superfamily and exhibit various functions in the fight against infections. The functions of the human guanylate binding protein 1 (hGBP1) are tightly coupled to GTP hydrolysis and dimerization. Despite known crystal structures of the hGBP1 monomer and GTPase domain dimer, little is known about the dynamics of hGBP1. To gain a mechanistic understanding of hGBP1, we performed sub-millisecond multi-resolution molecular dynamics simulations of both the hGBP1 monomer and dimer. We found that hGBP1 is a highly flexible protein that undergoes a hinge motion similar to the movements observed for other dynamin-like proteins. Another large-scale motion was observed for the C-terminal helix α13, providing a molecular view for the α13-α13 distances previously reported for the hGBP1 dimer. Most of the loops of the GTPase domain were found to be flexible, revealing why GTP binding is needed for hGBP1 dimerization to occur.
Collapse
Affiliation(s)
- Bogdan Barz
- Institute of Physical Biology, Heinrich Heine University, Düsseldorf, Germany
| | - Jennifer Loschwitz
- Institute of Complex Systems: Structural Biochemistry, Forschungszentrum Jülich, Jülich, Germany
- Institute of Theoretical and Computational Chemistry, Heinrich Heine University, Düsseldorf, Germany
| | - Birgit Strodel
- Institute of Complex Systems: Structural Biochemistry, Forschungszentrum Jülich, Jülich, Germany
- Institute of Theoretical and Computational Chemistry, Heinrich Heine University, Düsseldorf, Germany
| |
Collapse
|
15
|
Yu J, Sharma M, Delikanli S, Birowosuto MD, Demir HV, Dang C. Mutual Energy Transfer in a Binary Colloidal Quantum Well Complex. J Phys Chem Lett 2019; 10:5193-5199. [PMID: 31434477 DOI: 10.1021/acs.jpclett.9b01939] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Förster resonance energy transfer (FRET) is a fundamental process that is key to optical biosensing, photosynthetic light harvesting, and down-converted light emission. However, in total, conventional FRET in a donor-acceptor pair is essentially unidirectional, which impedes practical application of FRET-based technologies. Here, we propose a mutual FRET scheme that is uniquely bidirectional in a binary colloidal quantum well (CQW) complex enabled by utilizing the d orbital electrons in a dopant-host CQW system. Steady-state emission intensity, time-resolved, and photoluminescence excitation spectroscopies have demonstrated that two distinct CQWs play the role of donor and acceptor simultaneously in this complex consisting of 3 monolayer (ML) copper-doped CQWs and 4 ML undoped CQWs. Band-edge excitons in 3 ML CQWs effectively transfer the excitation to excitons in 4 ML CQWs, whose energy is also harvested backward by the dopants in 3 ML CQWs. This binary CQW complex, which offers a unique mutual energy-transfer mechanism, may unlock revolutionary FRET-based technologies.
Collapse
Affiliation(s)
- Junhong Yu
- LUMINOUS! Centre of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, The Photonics Institute (TPI), Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore
| | - Manoj Sharma
- LUMINOUS! Centre of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, The Photonics Institute (TPI), Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore
- Department of Electrical and Electronics Engineering and Department of Physics, UNAM-Institute of Materials Science and Nanotechnology, Bilkent University, Bilkent, Ankara 06800, Turkey
| | - Savas Delikanli
- LUMINOUS! Centre of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, The Photonics Institute (TPI), Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore
- Department of Electrical and Electronics Engineering and Department of Physics, UNAM-Institute of Materials Science and Nanotechnology, Bilkent University, Bilkent, Ankara 06800, Turkey
| | - Muhammad Danang Birowosuto
- CINTRA UMI CNRS/NTU/THALES 3288, Research Techno Plaza, 50 Nanyang Drive, Border X Block, Level 6, 637553 Singapore
| | - Hilmi Volkan Demir
- LUMINOUS! Centre of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, The Photonics Institute (TPI), Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore
- Department of Electrical and Electronics Engineering and Department of Physics, UNAM-Institute of Materials Science and Nanotechnology, Bilkent University, Bilkent, Ankara 06800, Turkey
- School of Physical and Mathematical Sciences, Division of Physics and Applied Physics, Nanyang Technological University, 639798 Singapore
| | - Cuong Dang
- LUMINOUS! Centre of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, The Photonics Institute (TPI), Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore
- CINTRA UMI CNRS/NTU/THALES 3288, Research Techno Plaza, 50 Nanyang Drive, Border X Block, Level 6, 637553 Singapore
| |
Collapse
|
16
|
Mx1 in Hematopoietic Cells Protects against Thogoto Virus Infection. J Virol 2019; 93:JVI.00193-19. [PMID: 31092574 DOI: 10.1128/jvi.00193-19] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 05/07/2019] [Indexed: 02/06/2023] Open
Abstract
Myxovirus resistance 1 (Mx1) is an interferon-induced gene that encodes a GTPase that plays an important role in the defense of mammalian cells against influenza A and other viruses. The Mx1 protein can restrict a number of viruses independently of the expression of other interferon-induced genes. Mx genes are therefore considered to be an important part of the innate antiviral immune response. However, the possible impact of Mx expression in the hematopoietic cellular compartment has not been investigated in detail in the course of a viral infection. To address this, we performed bone marrow chimera experiments using congenic B6.A2G Mx1 +/+ and B6.A2G Mx1-/- mice to study the effect of Mx1 expression in cells of hematopoietic versus nonhematopoietic origin. Mx1+/+ mice were protected and Mx1-/- mice were susceptible to influenza A virus challenge infection, regardless of the type of bone marrow cells (Mx1 +/+ or Mx1-/- ) the animals had received. Infection with Thogoto virus, however, revealed that Mx1-/- mice with a functional Mx1 gene in the bone marrow compartment showed reduced liver pathology compared with Mx1-/- mice that had been grafted with Mx1 -/- bone marrow. The reduced pathology in these mice was associated with a reduction in Thogoto virus titers in the spleen, lung, and serum. Moreover, Mx1 +/+ mice with Mx1 -/- bone marrow failed to control Thogoto virus replication in the spleen. Mx1 in the hematopoietic cellular compartment thus contributes to protection against Thogoto virus infection.IMPORTANCE Mx proteins are evolutionarily conserved in vertebrates and can restrict a wide range of viruses in a cell-autonomous way. The contribution to antiviral defense of Mx1 expression in hematopoietic cells remains largely unknown. We show that protection against influenza virus infection requires Mx1 expression in the nonhematopoietic cellular compartment. In contrast, Mx1 in bone marrow-derived cells is sufficient to control disease and virus replication following infection with a Thogoto virus. This indicates that, in addition to its well-established antiviral activity in nonhematopoietic cells, Mx1 in hematopoietic cells can also play an important antiviral function. In addition, cells of hematopoietic origin that lack a functional Mx1 gene contribute to Thogoto virus dissemination and associated disease.
Collapse
|
17
|
smFRET Probing Reveals Substrate-Dependent Conformational Dynamics of E. coli Multidrug MdfA. Biophys J 2019; 116:2296-2303. [PMID: 31146923 DOI: 10.1016/j.bpj.2019.04.034] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 04/10/2019] [Accepted: 04/23/2019] [Indexed: 11/21/2022] Open
Abstract
Bacterial multidrug-resistance transporters of the major facilitator superfamily are distinguished by their extraordinary ability to bind structurally diverse substrates, thus serving as a highly efficient tool to protect cells from multiple toxic substances present in their environment, including antibiotic drugs. However, details of the dynamic conformational changes of the transport cycle involved remain to be elucidated. Here, we used the single-molecule fluorescence resonance energy transfer technique to investigate the conformational behavior of the Escherichia coli multidrug transporter MdfA under conditions of different substrates, pH, and alkali metal ions. Our data show that different substrates exhibit distinct effects on both the conformational distribution and transition rate between two major conformations. Although the cationic substrate tetraphenylphosphonium favors the outward-facing conformation, it has less effect on the transition rate. In contrast, binding of the electroneutral substrate chloramphenicol tends to stabilize the inward-facing conformation and decreases the transition rate. Therefore, our study supports the notion that the MdfA transporter uses distinct mechanisms to transport electroneutral and cationic substrates.
Collapse
|
18
|
Zav'yalov VP, Hämäläinen-Laanaya H, Korpela TK, Wahlroos T. Interferon-Inducible Myxovirus Resistance Proteins: Potential Biomarkers for Differentiating Viral from Bacterial Infections. Clin Chem 2018; 65:739-750. [PMID: 30593466 PMCID: PMC7108468 DOI: 10.1373/clinchem.2018.292391] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 08/29/2018] [Indexed: 12/31/2022]
Abstract
BACKGROUND In 2015, the 68th World Health Assembly declared that effective, rapid, low-cost diagnostic tools were needed for guiding optimal use of antibiotics in medicine. This review is devoted to interferon-inducible myxovirus resistance proteins as potential biomarkers for differentiating viral from bacterial infections. CONTENT After viral infection, a branch of the interferon (IFN)-induced molecular reactions is triggered by the binding of IFNs with their receptors, a process leading to the activation of mx1 and mx2, which produce antiviral Mx proteins (MxA and MxB). We summarize current knowledge of the structures and functions of type I and III IFNs. Antiviral mechanisms of Mx proteins are discussed in reference to their structural and functional data to provide an in-depth picture of protection against viral attacks. Knowing such a mechanism may allow the development of countermeasures and the specific detection of any viral infection. Clinical research data indicate that Mx proteins are biomarkers for many virus infections, with some exceptions, whereas C-reactive protein (CRP) and procalcitonin have established positions as general biomarkers for bacterial infections. SUMMARY Mx genes are not directly induced by viruses and are not expressed constitutively; their expression strictly depends on IFN signaling. MxA protein production in peripheral blood cells has been shown to be a clinically sensitive and specific marker for viral infection. Viral infections specifically increase MxA concentrations, whereas viruses have only a modest increase in CRP or procalcitonin concentrations. Therefore, comparison of MxA and CRP and/or procalcitonin values can be used for the differentiation of infectious etiology.
Collapse
Affiliation(s)
| | | | - Timo K Korpela
- Department of Future Technologies, University of Turku, Turku, Finland
| | - Tony Wahlroos
- Laboratory of Clinical Research, Labmaster Ltd., Turku, Finland
| |
Collapse
|
19
|
Human MX2/MxB: a Potent Interferon-Induced Postentry Inhibitor of Herpesviruses and HIV-1. J Virol 2018; 92:JVI.00709-18. [PMID: 30258007 DOI: 10.1128/jvi.00709-18] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Interferons limit viral replication by inducing intracellular restriction factors, such as the GTPase MxB (also designated MX2), which inhibits HIV-1 and, as recently shown, herpesviruses. Inhibition of these viruses occurs at ill-defined steps after viral entry and requires formation of MxB dimers or oligomers, but GTP hydrolysis is needed only for blocking herpesviruses. Together with previous findings on related MxA, the new research on MxB highlights the mechanistic diversity by which MX proteins interfere with viral replication.
Collapse
|
20
|
Ringer K, Riehl J, Müller M, Dewes J, Hoff F, Jacob R. The large GTPase Mx1 binds Kif5B for cargo transport along microtubules. Traffic 2018; 19:947-964. [DOI: 10.1111/tra.12616] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 09/18/2018] [Accepted: 09/18/2018] [Indexed: 01/29/2023]
Affiliation(s)
- Karina Ringer
- Department of Cell Biology and Cell Pathology; Philipps University of Marburg; Marburg Germany
- DFG Research Training Group, Membrane Plasticity in Tissue Development and Remodeling; Philipps University of Marburg; Marburg Germany
| | - Jana Riehl
- Department of Cell Biology and Cell Pathology; Philipps University of Marburg; Marburg Germany
| | - Manuel Müller
- Department of Cell Biology and Cell Pathology; Philipps University of Marburg; Marburg Germany
| | - Jenny Dewes
- Department of Cell Biology and Cell Pathology; Philipps University of Marburg; Marburg Germany
| | - Florian Hoff
- Department of Cell Biology and Cell Pathology; Philipps University of Marburg; Marburg Germany
| | - Ralf Jacob
- Department of Cell Biology and Cell Pathology; Philipps University of Marburg; Marburg Germany
- DFG Research Training Group, Membrane Plasticity in Tissue Development and Remodeling; Philipps University of Marburg; Marburg Germany
| |
Collapse
|
21
|
Structural basis for membrane tethering by a bacterial dynamin-like pair. Nat Commun 2018; 9:3345. [PMID: 30131557 PMCID: PMC6104087 DOI: 10.1038/s41467-018-05523-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2018] [Accepted: 07/11/2018] [Indexed: 01/11/2023] Open
Abstract
Dynamin-like proteins (DLPs) are large GTPases that restructure membrane. DLPs such as the mitofusins form heterotypic oligomers between isoform pairs that bridge and fuse opposing membranes. In bacteria, heterotypic oligomerisation may also be important for membrane remodelling as most DLP genes are paired within operons. How DLPs tether opposing membranes is unknown. Here we show the crystal structure of a DLP heterotypic pair from the pathogen Campylobacter jejuni. A 2:2 stoichiometric tetramer is observed where heterodimers, conjoined by a random coil linker, assemble back-to-back to form a tripartite DLP chain with extreme flexibility. In vitro, tetramerisation triggers GTPase activity and induces lipid binding. Liposomes are readily tethered and form tubes at high tetramer concentration. Our results provide a direct mechanism for the long-range binding and bridging of opposing membranes by a bacterial DLP pair. They also provide broad mechanistic and structural insights that are relevant to other heterotypic DLP complexes. Dynamin-like proteins (DLPs) such as the mitofusins form homotypic and heterotypic oligomers that bridge and fuse opposing membranes. Here, Liu, Noel and Low present the crystal structure of a bacterial DLP heterotypic pair, providing insights into the mechanism behind long-range binding of opposing membranes.
Collapse
|
22
|
Bohuszewicz O, Low HH. Structure of a mitochondrial fission dynamin in the closed conformation. Nat Struct Mol Biol 2018; 25:722-731. [PMID: 30061604 PMCID: PMC6104806 DOI: 10.1038/s41594-018-0097-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Accepted: 06/26/2018] [Indexed: 01/05/2023]
Abstract
Dynamin 1-like proteins (DNM1-L) are mechanochemical GTPases that induce membrane fission in mitochondria and peroxisomes. Their mechanism depends on conformational changes driven by nucleotide and lipid cycling. Here we show the crystal structure of a mitochondrial fission dynamin (CmDnm1) from the algae Cyanidioschyzon merolae. Unlike other eukaryotic dynamin structures, CmDnm1 is in a hinge 1 closed conformation, with the GTPase domain compacted against the stalk. Within the crystal, CmDnm1 packs as a diamond-shaped tetramer that is consistent with an inactive off-membrane state. Crosslinking, photoinduced electron transfer assays, and electron microscopy verify these structures. In vitro, CmDnm1 forms concentration-dependent rings and protein-lipid tubes reminiscent of DNM1-L and classical dynamin with hinge 1 open. Our data provides a mechanism for filament collapse and membrane release that may extend to other dynamin family members. Additionally, hinge 1 closing may represent a key conformational change that contributes to membrane fission.
Collapse
Affiliation(s)
| | - Harry H Low
- Department of Life Sciences, Imperial College, London, UK.
| |
Collapse
|
23
|
Porcine Mx1 Protein Inhibits Classical Swine Fever Virus Replication by Targeting Nonstructural Protein NS5B. J Virol 2018; 92:JVI.02147-17. [PMID: 29343573 DOI: 10.1128/jvi.02147-17] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 01/09/2018] [Indexed: 12/16/2022] Open
Abstract
Mx proteins are interferon (IFN)-induced GTPases that have broad antiviral activity against a wide range of RNA and DNA viruses; they belong to the dynamin superfamily of large GTPases. In this study, we confirmed the anti-classical swine fever virus (CSFV) activity of porcine Mx1 in vitro and showed that porcine Mx2 (poMx2), human MxA (huMxA), and mouse Mx1 (mmMx1) also have anti-CSFV activity in vitro Small interfering RNA (siRNA) experiments revealed that depletion of endogenous poMx1 or poMx2 enhanced CSFV replication, suggesting that porcine Mx proteins are responsible for the antiviral activity of interferon alpha (IFN-α) against CSFV infection. Confocal microscopy, immunoprecipitation, glutathione S-transferase (GST) pulldown, and bimolecular fluorescence complementation (BiFC) demonstrated that poMx1 associated with NS5B, the RNA-dependent RNA polymerase (RdRp) of CSFV. We used mutations in the poMx1 protein to elucidate the mechanism of their anti-CSFV activity and found that mutants that disrupted the association with NS5B lost all anti-CSV activity. Moreover, an RdRp activity assay further revealed that poMx1 undermined the RdRp activities of NS5B. Together, these results indicate that porcine Mx proteins exert their antiviral activity against CSFV by interacting with NS5B.IMPORTANCE Our previous studies have shown that porcine Mx1 (poMx1) inhibits classical swine fever virus (CSFV) replication in vitro and in vivo, but the molecular mechanism of action remains largely unknown. In this study, we dissect the molecular mechanism of porcine Mx1 and Mx2 against CSFV in vitro Our results show that poMx1 associates with NS5B, the RNA-dependent RNA polymerase of CSFV, resulting in the reduction of CSFV replication. Moreover, the mutants of poMx1 further elucidate the mechanism of their anti-CSFV activities.
Collapse
|
24
|
Yan L, Qi Y, Huang X, Yu C, Lan L, Guo X, Rao Z, Hu J, Lou Z. Structural basis for GTP hydrolysis and conformational change of MFN1 in mediating membrane fusion. Nat Struct Mol Biol 2018; 25:233-243. [PMID: 29483649 DOI: 10.1038/s41594-018-0034-8] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Accepted: 01/24/2018] [Indexed: 01/05/2023]
Abstract
Fusion of the outer mitochondrial membrane is mediated by the dynamin-like GTPase mitofusin (MFN). Here, we determined the structure of the minimal GTPase domain (MGD) of human MFN1 in complex with GDP-BeF3-. The MGD folds into a canonical GTPase fold with an associating four-helix bundle, HB1, and forms a dimer. A potassium ion in the catalytic core engages GDP and BeF3- (GDP-BeF3-). Enzymatic analysis has confirmed that efficient GTP hydrolysis by MFN1 requires potassium. Compared to previously reported MGD structures, the HB1 structure undergoes a major conformational change relative to the GTPase domains, as they move from pointing in opposite directions to point in the same direction, suggesting that a swing of the four-helix bundle can pull tethered membranes closer to achieve fusion. The proposed model is supported by results from in vitro biochemical assays and mitochondria morphology rescue assays in MFN1-deleted cells. These findings offer an explanation for how Charcot-Marie-Tooth neuropathy type 2 A (CMT2A)-causing mutations compromise MFN-mediated fusion.
Collapse
Affiliation(s)
- Liming Yan
- School of Medicine, Tsinghua University, Beijing, China
| | - Yuanbo Qi
- Department of Genetics and Cell Biology, College of Life Sciences, Nankai University, and Tianjin Key Laboratory of Protein Sciences, Tianjin, China
| | - Xiaofang Huang
- Department of Genetics and Cell Biology, College of Life Sciences, Nankai University, and Tianjin Key Laboratory of Protein Sciences, Tianjin, China
| | - Caiting Yu
- School of Medicine, Tsinghua University, Beijing, China
| | - Lan Lan
- National Laboratory of Macromolecules, Institute of Biophysics, Chinese Academy of Science, Beijing, China
| | - Xiangyang Guo
- Department of Genetics and Cell Biology, College of Life Sciences, Nankai University, and Tianjin Key Laboratory of Protein Sciences, Tianjin, China
| | - Zihe Rao
- School of Medicine, Tsinghua University, Beijing, China.,National Laboratory of Macromolecules, Institute of Biophysics, Chinese Academy of Science, Beijing, China
| | - Junjie Hu
- National Laboratory of Macromolecules, Institute of Biophysics, Chinese Academy of Science, Beijing, China.
| | - Zhiyong Lou
- School of Medicine, Tsinghua University, Beijing, China. .,Collaborative Innovation Center for Biotherapy, Tsinghua University, Tsinghua, China.
| |
Collapse
|
25
|
Graf L, Dick A, Sendker F, Barth E, Marz M, Daumke O, Kochs G. Effects of allelic variations in the human myxovirus resistance protein A on its antiviral activity. J Biol Chem 2018; 293:3056-3072. [PMID: 29330299 DOI: 10.1074/jbc.m117.812784] [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: 08/16/2017] [Revised: 01/08/2018] [Indexed: 11/06/2022] Open
Abstract
Only a minority of patients infected with seasonal influenza A viruses exhibit a severe or fatal outcome of infection, but the reasons for this inter-individual variability in influenza susceptibility are unclear. To gain further insights into the molecular mechanisms underlying this variability, we investigated naturally occurring allelic variations of the myxovirus resistance 1 (MX1) gene coding for the influenza restriction factor MxA. The interferon-induced dynamin-like GTPase consists of an N-terminal GTPase domain, a bundle signaling element, and a C-terminal stalk responsible for oligomerization and viral target recognition. We used online databases to search for variations in the MX1 gene. Deploying in vitro approaches, we found that non-synonymous variations in the GTPase domain cause the loss of antiviral and enzymatic activities. Furthermore, we showed that these amino acid substitutions disrupt the interface for GTPase domain dimerization required for the stimulation of GTP hydrolysis. Variations in the stalk were neutral or slightly enhanced or abolished MxA antiviral function. Remarkably, two other stalk variants altered MxA's antiviral specificity. Variations causing the loss of antiviral activity were found only in heterozygous carriers. Interestingly, the inactive stalk variants blocked the antiviral activity of WT MxA in a dominant-negative way, suggesting that heterozygotes are phenotypically MxA-negative. In contrast, the GTPase-deficient variants showed no dominant-negative effect, indicating that heterozygous carriers should remain unaffected. Our results demonstrate that naturally occurring mutations in the human MX1 gene can influence MxA function, which may explain individual variations in influenza virus susceptibility in the human population.
Collapse
Affiliation(s)
- Laura Graf
- From the Institute of Virology, Medical Center-University of Freiburg, Hermann-Herder-Strasse 11, 79104 Freiburg, Germany.,the Spemann Graduate School of Biology and Medicine, University of Freiburg, Albertstrasse 19a, 79104 Freiburg, Germany
| | - Alexej Dick
- the Max-Delbrück Centrum for Molecular Medicine, Robert-Rössle-Strasse 10, 13125 Berlin, Germany.,the Institute of Chemistry and Biochemistry, Free University Berlin, Takustrasse 6, 14195 Berlin, Germany
| | - Franziska Sendker
- From the Institute of Virology, Medical Center-University of Freiburg, Hermann-Herder-Strasse 11, 79104 Freiburg, Germany
| | - Emanuel Barth
- the Bioinformatics/High Throughput Analysis, Friedrich Schiller University Jena, Leutragraben 1, 07743 Jena, Germany
| | - Manja Marz
- the Bioinformatics/High Throughput Analysis, Friedrich Schiller University Jena, Leutragraben 1, 07743 Jena, Germany.,the Leibniz Institute for Age Research-Fritz Lipmann Institute (FLI), Beutenbergstrasse 11, 07745 Jena, Germany.,the European Virus Bioinformatics Center, Leutragraben 1, 07743 Jena, Germany, and
| | - Oliver Daumke
- the Max-Delbrück Centrum for Molecular Medicine, Robert-Rössle-Strasse 10, 13125 Berlin, Germany, .,the Institute of Chemistry and Biochemistry, Free University Berlin, Takustrasse 6, 14195 Berlin, Germany
| | - Georg Kochs
- From the Institute of Virology, Medical Center-University of Freiburg, Hermann-Herder-Strasse 11, 79104 Freiburg, Germany, .,the Spemann Graduate School of Biology and Medicine, University of Freiburg, Albertstrasse 19a, 79104 Freiburg, Germany.,the Faculty of Medicine, University of Freiburg, 79085 Freiburg, Germany
| |
Collapse
|
26
|
Voith von Voithenberg L, Lamb DC. Single Pair Förster Resonance Energy Transfer: A Versatile Tool To Investigate Protein Conformational Dynamics. Bioessays 2018; 40. [DOI: 10.1002/bies.201700078] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 12/05/2017] [Indexed: 01/23/2023]
Affiliation(s)
- Lena Voith von Voithenberg
- Department Chemie; Center for Nanoscience (CeNS); Center for Integrated Protein Science Munich (CIPSM); Nanosystem Initiative Munich (NIM); Ludwig-Maximilians-Universität München; Butenandtstr. 5-13 81377 München Germany
- BIOSS Centre for Signalling Studies; Schänzlestr. 18 79104 Freiburg Germany
| | - Don C. Lamb
- Department Chemie; Center for Nanoscience (CeNS); Center for Integrated Protein Science Munich (CIPSM); Nanosystem Initiative Munich (NIM); Ludwig-Maximilians-Universität München; Butenandtstr. 5-13 81377 München Germany
| |
Collapse
|
27
|
Vaishnav JK, Mukherjee TK. Tuning of resonance energy transfer from 4′,6-diamidino-2-phenylindole to an ultrasmall silver nanocluster across the lipid bilayer. Phys Chem Chem Phys 2017; 19:27305-27312. [DOI: 10.1039/c7cp05225a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Liposome mediated efficient tuning of FRET between photoexcited 4′,6-diamidino-2-phenylindole (DAPI) and an ultrasmall silver nanocluster (Ag NC) has been demonstrated using steady-state and time-resolved fluorescence spectroscopy.
Collapse
Affiliation(s)
- Jamuna K. Vaishnav
- Discipline of Chemistry
- Indian Institute of Technology Indore
- Indore-453552
- India
| | | |
Collapse
|