@phdthesis{Dahmani2021, author = {Dahmani, Ismail}, title = {Influenza A virus matrix protein M1}, doi = {10.25932/publishup-52740}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-527409}, school = {Universit{\"a}t Potsdam}, pages = {XI, 147}, year = {2021}, abstract = {Influenza A virus (IAV) is a pathogen responsible for severe seasonal epidemics threatening human and animal populations every year. During the viral assembly process in the infected cells, the plasma membrane (PM) has to bend in localized regions into a vesicle towards the extracellular side. Studies in cellular models have proposed that different viral proteins might be responsible for inducing membrane curvature in this context (including M1), but a clear consensus has not been reached. M1 is the most abundant protein in IAV particles. It plays an important role in virus assembly and budding at the PM. M1 is recruited to the host cell membrane where it associates with lipids and other viral proteins. However, the details of M1 interactions with the cellular PM, as well as M1-mediated membrane bending at the budozone, have not been clarified. In this work, we used several experimental approaches to analyze M1-lipids and M1-M1 interactions. By performing SPR analysis, we quantified membrane association for full-length M1 and different genetically engineered M1 constructs (i.e., N- and C-terminally truncated constructs and a mutant of the polybasic region). This allowed us to obtain novel information on the protein regions mediating M1 binding to membranes. By using fluorescence microscopy, cryogenic transmission electron microscopy (cryo-TEM), and three-dimensional (3D) tomography (cryo-ET), we showed that M1 is indeed able to cause membrane deformation on vesicles containing negatively-charged lipids, in the absence of other viral components. Further, sFCS analysis proved that simple protein binding is not sufficient to induce membrane restructuring. Rather, it appears that stable M1-M1 interactions and multimer formation are required to alter the bilayer three-dimensional structure through the formation of a protein scaffold. Finally, to mimic the budding mechanism in cells that arise by the lateral organization of the virus membrane components on lipid raft domains, we created vesicles with lipid domains. Our results showed that local binding of M1 to spatial confined acidic lipids within membrane domains of vesicles led to local M1 inward curvature.}, language = {en} } @article{KolyvushkoLatzkeDahmanietal.2020, author = {Kolyvushko, Oleksandr and Latzke, Juliane and Dahmani, Ismail and Osterrieder, Nikolaus and Chiantia, Salvatore and Azab, Walid}, title = {Differentially-charged liposomes interact with alphaherpesviruses and interfere with virus entry}, series = {Pathogens}, volume = {9}, journal = {Pathogens}, number = {5}, publisher = {MDPI}, address = {Basel}, issn = {2076-0817}, doi = {10.3390/pathogens9050359}, pages = {9}, year = {2020}, abstract = {Exposure of phosphatidylserine (PS) in the outer leaflet of the plasma membrane is induced by infection with several members of the Alphaherpesvirinae subfamily. There is evidence that PS is used by the equine herpesvirus type 1 (EHV-1) during entry, but the exact role of PS and other phospholipids in the entry process remains unknown. Here, we investigated the interaction of differently charged phospholipids with virus particles and determined their influence on infection. Our data show that liposomes containing negatively charged PS or positively charged DOTAP (N-[1-(2,3-Dioleoyloxy)propyl]-N,N,N-trimethylammonium) inhibited EHV-1 infection, while neutral phosphatidylcholine (PC) had no effect. Inhibition of infection with PS was transient, decreased with time, and was dose dependent. Our findings indicate that both cationic and anionic phospholipids can interact with the virus and reduce infectivity, while, presumably, acting through different mechanisms. Charged phospholipids were found to have antiviral effects and may be used to inhibit EHV-1 infection.}, language = {en} } @misc{KolyvushkoLatzkeDahmanietal.2020, author = {Kolyvushko, Oleksandr and Latzke, Juliane and Dahmani, Ismail and Osterrieder, Nikolaus and Chiantia, Salvatore and Azab, Walid}, title = {Differentially-charged liposomes interact with alphaherpesviruses and interfere with virus entry}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {1088}, issn = {1866-8372}, doi = {10.25932/publishup-47189}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-471895}, pages = {11}, year = {2020}, abstract = {Exposure of phosphatidylserine (PS) in the outer leaflet of the plasma membrane is induced by infection with several members of the Alphaherpesvirinae subfamily. There is evidence that PS is used by the equine herpesvirus type 1 (EHV-1) during entry, but the exact role of PS and other phospholipids in the entry process remains unknown. Here, we investigated the interaction of differently charged phospholipids with virus particles and determined their influence on infection. Our data show that liposomes containing negatively charged PS or positively charged DOTAP (N-[1-(2,3-Dioleoyloxy)propyl]-N,N,N-trimethylammonium) inhibited EHV-1 infection, while neutral phosphatidylcholine (PC) had no effect. Inhibition of infection with PS was transient, decreased with time, and was dose dependent. Our findings indicate that both cationic and anionic phospholipids can interact with the virus and reduce infectivity, while, presumably, acting through different mechanisms. Charged phospholipids were found to have antiviral effects and may be used to inhibit EHV-1 infection.}, language = {en} } @misc{HoeferDiLellaDahmanietal.2019, author = {H{\"o}fer, Chris Tina and Di Lella, Santiago and Dahmani, Ismail and Jungnick, Nadine and Bordag, Natalie and Bobone, Sara and Huan, Q. and Keller, S. and Herrmann, A. and Chiantia, Salvatore}, title = {Corrigendum to: Structural determinants of the interaction between influenza A virus matrix protein M1 and lipid membranes (Biochimica et Biophysica Acta (BBA) - Biomembranes. - 1861, (2019), pg 1123-1134)}, series = {Biochimica et biophysica acta : Biomembranes}, volume = {1861}, journal = {Biochimica et biophysica acta : Biomembranes}, number = {10}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0005-2736}, doi = {10.1016/j.bbamem.2019.07.002}, pages = {1}, year = {2019}, language = {en} } @misc{DahmaniLudwigChiantia2019, author = {Dahmani, Ismail and Ludwig, Kai and Chiantia, Salvatore}, title = {Influenza A matrix protein M1 induces lipid membrane deformation via protein multimerization}, series = {Postprints der Universit{\"a}t Potsdam Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam Mathematisch-Naturwissenschaftliche Reihe}, number = {768}, issn = {1866-8372}, doi = {10.25932/publishup-43868}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-438689}, pages = {16}, year = {2019}, abstract = {The matrix protein M1 of the Influenza A virus (IAV) is supposed to mediate viral assembly and budding at the plasma membrane (PM) of infected cells. In order for a new viral particle to form, the PM lipid bilayer has to bend into a vesicle toward the extracellular side. Studies in cellular models have proposed that different viral proteins might be responsible for inducing membrane curvature in this context (including M1), but a clear consensus has not been reached. In the present study, we use a combination of fluorescence microscopy, cryogenic transmission electron microscopy (cryo-TEM), cryo-electron tomography (cryo-ET) and scanning fluorescence correlation spectroscopy (sFCS) to investigate M1-induced membrane deformation in biophysical models of the PM. Our results indicate that M1 is indeed able to cause membrane curvature in lipid bilayers containing negatively charged lipids, in the absence of other viral components. Furthermore, we prove that protein binding is not sufficient to induce membrane restructuring. Rather, it appears that stable M1-M1 interactions and multimer formation are required in order to alter the bilayer three-dimensional structure, through the formation of a protein scaffold. Finally, our results suggest that, in a physiological context,M1-induced membrane deformation might be modulated by the initial bilayer curvature and the lateral organization of membrane components (i.e. the presence of lipid domains).}, language = {en} } @article{HoeferDiLellaDahmanietal.2019, author = {H{\"o}fer, C. T. and Di Lella, S. and Dahmani, Ismail and Jungnick, N. and Bordag, N. and Bobone, Sara and Huang, Q. and Keller, S. and Herrmann, A. and Chiantia, Salvatore}, title = {Structural determinants of the interaction between influenza A virus matrix protein M1 and lipid membranes}, series = {Biochimica et biophysica acta : Biomembranes}, volume = {1861}, journal = {Biochimica et biophysica acta : Biomembranes}, number = {6}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0005-2736}, doi = {10.1016/j.bbamem.2019.03.013}, pages = {1123 -- 1134}, year = {2019}, abstract = {Influenza A virus is a pathogen responsible for severe seasonal epidemics threatening human and animal populations every year. One of the ten major proteins encoded by the viral genome, the matrix protein M1, is abundantly produced in infected cells and plays a structural role in determining the morphology of the virus. During assembly of new viral particles, M1 is recruited to the host cell membrane where it associates with lipids and other viral proteins. The structure of M1 is only partially known. In particular, structural details of M1 interactions with the cellular plasma membrane as well as M1 protein interactions and multimerization have not been clarified, yet. In this work, we employed a set of complementary experimental and theoretical tools to tackle these issues. Using raster image correlation, surface plasmon resonance and circular dichroism spectroscopies, we quantified membrane association and oligomerization of full-length M1 and of different genetically engineered M1 constructs (i.e., N- and C-terminally truncated constructs and a mutant of the polybasic region, residues 95-105). Furthermore, we report novel information on structural changes in M1 occurring upon binding to membranes. Our experimental results are corroborated by an all-atom model of the full-length M1 protein bound to a negatively charged lipid bilayer.}, language = {en} } @article{DahmaniLudwigChiantia2019, author = {Dahmani, Ismail and Ludwig, Kai and Chiantia, Salvatore}, title = {Influenza A matrix protein M1 induces lipid membrane deformation via protein multimerization}, series = {Bioscience Reports}, volume = {39}, journal = {Bioscience Reports}, number = {8}, publisher = {Portland Press}, address = {Colchester}, issn = {0144-8463}, doi = {10.1042/BSR20191024}, pages = {16}, year = {2019}, abstract = {The matrix protein M1 of the Influenza A virus (IAV) is supposed to mediate viral assembly and budding at the plasma membrane (PM) of infected cells. In order for a new viral particle to form, the PM lipid bilayer has to bend into a vesicle toward the extracellular side. Studies in cellular models have proposed that different viral proteins might be responsible for inducing membrane curvature in this context (including M1), but a clear consensus has not been reached. In the present study, we use a combination of fluorescence microscopy, cryogenic transmission electron microscopy (cryo-TEM), cryo-electron tomography (cryo-ET) and scanning fluorescence correlation spectroscopy (sFCS) to investigate M1-induced membrane deformation in biophysical models of the PM. Our results indicate that M1 is indeed able to cause membrane curvature in lipid bilayers containing negatively charged lipids, in the absence of other viral components. Furthermore, we prove that protein binding is not sufficient to induce membrane restructuring. Rather, it appears that stable M1-M1 interactions and multimer formation are required in order to alter the bilayer three-dimensional structure, through the formation of a protein scaffold. Finally, our results suggest that, in a physiological context,M1-induced membrane deformation might be modulated by the initial bilayer curvature and the lateral organization of membrane components (i.e. the presence of lipid domains).}, language = {en} } @article{DeyBergmannCuellarCamachoetal.2018, author = {Dey, Pradip and Bergmann, Tobias and Cuellar-Camacho, Jose Luis and Ehrmann, Svenja and Chowdhury, Mohammad Suman and Zhang, Minze and Dahmani, Ismail and Haag, Rainer and Azad, Walid}, title = {Multivalent flexible nanogels exhibit broad-spectrum antiviral activity by blocking virus entry}, series = {ACS nano}, volume = {12}, journal = {ACS nano}, number = {7}, publisher = {American Chemical Society}, address = {Washington}, issn = {1936-0851}, doi = {10.1021/acsnano.8b01616}, pages = {6429 -- 6442}, year = {2018}, abstract = {The entry process of viruses into host cells is complex and involves stable but transient multivalent interactions with different cell surface receptors. The initial contact of several viruses begins with attachment to heparan sulfate (HS) proteoglycans on the cell surface, which results in a cascade of events that end up with virus entry. The development of antiviral agents based on multivalent interactions to shield virus particles and block initial interactions with cellular receptors has attracted attention in antiviral research. Here, we designed nanogels with different degrees of flexibility based on dendritic polyglycerol sulfate to mimic cellular HS. The designed nanogels are nontoxic and broad-spectrum, can multivalently interact with viral glycoproteins, shield virus surfaces, and efficiently block infection. We also visualized virus-nanogel interactions as well as the uptake of nanogels by the cells through clathrin-mediated endocytosis using confocal microscopy. As many human viruses attach to the cells through HS moieties, we introduce our flexible nanogels as robust inhibitors for these viruses.}, language = {en} }