1
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Pan S, Gries K, Engel BD, Schroda M, Haselwandter CA, Scheuring S. The cyanobacterial protein VIPP1 forms ESCRT-III-like structures on lipid bilayers. Nat Struct Mol Biol 2024:10.1038/s41594-024-01367-7. [PMID: 39060677 DOI: 10.1038/s41594-024-01367-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Accepted: 07/03/2024] [Indexed: 07/28/2024]
Abstract
The biogenesis and maintenance of thylakoid membranes require vesicle-inducing protein in plastids 1 (VIPP1). VIPP1 is a member of the endosomal sorting complex required for transport-III (ESCRT-III) superfamily, whose members form diverse filament-based supramolecular structures that facilitate membrane deformation and fission. VIPP1 cryo-electron microscopy (EM) structures in solution revealed helical rods and baskets of stacked rings, with amphipathic membrane-binding domains in the lumen. However, how VIPP1 interacts with membranes remains largely unknown. Here, using high-speed atomic force microscopy (HS-AFM), we show that VIPP1 assembles into right-handed chiral spirals and regular polygons on supported lipid bilayers via ESCRT-III-like filament assembly and dynamics. VIPP1 filaments grow clockwise into spirals through polymerization at a ring-shaped central polymerization hub, and into polygons through clockwise polymerization at the sector peripheries. Interestingly, VIPP1 initially forms Archimedean spirals, which upon maturation transform into logarithmic spirals through lateral annealing of strands to the outermore low-curvature spiral turns.
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Affiliation(s)
- Sichen Pan
- Weill Cornell Medicine, Department of Anesthesiology, New York, NY, USA
| | - Karin Gries
- Molecular Biotechnology and Systems Biology, RPTU Kaiserslautern-Landau, Kaiserslautern, Germany
| | | | - Michael Schroda
- Molecular Biotechnology and Systems Biology, RPTU Kaiserslautern-Landau, Kaiserslautern, Germany
| | - Christoph A Haselwandter
- Department of Physics and Astronomy, University of Southern California, Los Angeles, CA, USA
- Department of Quantitative and Computational Biology, University of Southern California, Los Angeles, CA, USA
| | - Simon Scheuring
- Weill Cornell Medicine, Department of Anesthesiology, New York, NY, USA.
- Weill Cornell Medicine, Department of Physiology and Biophysics, New York, NY, USA.
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2
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Schlösser L, Sachse C, Low HH, Schneider D. Conserved structures of ESCRT-III superfamily members across domains of life. Trends Biochem Sci 2023; 48:993-1004. [PMID: 37718229 DOI: 10.1016/j.tibs.2023.08.009] [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: 06/07/2023] [Revised: 08/04/2023] [Accepted: 08/22/2023] [Indexed: 09/19/2023]
Abstract
Structural and evolutionary studies of cyanobacterial phage shock protein A (PspA) and inner membrane-associated protein of 30 kDa (IM30) have revealed that these proteins belong to the endosomal sorting complex required for transport-III (ESCRT-III) superfamily, which is conserved across all three domains of life. PspA and IM30 share secondary and tertiary structures with eukaryotic ESCRT-III proteins, whilst also oligomerizing via conserved interactions. Here, we examine the structures of bacterial ESCRT-III-like proteins and compare the monomeric and oligomerized forms with their eukaryotic counterparts. We discuss conserved interactions used for self-assembly and highlight key hinge regions that mediate oligomer ultrastructure versatility. Finally, we address the differences in nomenclature assigned to equivalent structural motifs in both the bacterial and eukaryotic fields and suggest a common nomenclature applicable across the ESCRT-III superfamily.
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Affiliation(s)
- Lukas Schlösser
- Department of Chemistry, Biochemistry, Johannes Gutenberg University Mainz, Germany
| | - Carsten Sachse
- Ernst-Ruska Centre for Microscopy and Spectroscopy with Electrons, ER-C-3/Structural Biology, Forschungszentrum Jülich, 52425 Jülich, Germany; Institute for Biological Information Processing/IBI-6 Cellular Structural Biology, Jülich, Germany; Department of Biology, Heinrich Heine University, Universitätsstr. 1, 40225 Düsseldorf, Germany
| | - Harry H Low
- Department of Infectious Disease, Imperial College, London, UK
| | - Dirk Schneider
- Department of Chemistry, Biochemistry, Johannes Gutenberg University Mainz, Germany; Institute of Molecular Physiology, Johannes Gutenberg University Mainz, Mainz, Germany.
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3
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Junglas B, Axt A, Siebenaller C, Sonel H, Hellmann N, Weber SAL, Schneider D. Membrane destabilization and pore formation induced by the Synechocystis IM30 protein. Biophys J 2022; 121:3411-3421. [PMID: 35986519 PMCID: PMC9515227 DOI: 10.1016/j.bpj.2022.08.014] [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: 03/18/2022] [Revised: 07/21/2022] [Accepted: 08/15/2022] [Indexed: 11/18/2022] Open
Abstract
The inner membrane-associated protein of 30 kDa (IM30) is essential in chloroplasts and cyanobacteria. The spatio-temporal cellular localization of the protein appears to be highly dynamic and triggered by internal as well as external stimuli, mainly light intensity. The soluble fraction of the protein is localized in the cyanobacterial cytoplasm or the chloroplast stroma, respectively. Additionally, the protein attaches to the thylakoid membrane as well as to the chloroplast inner envelope or the cyanobacterial cytoplasmic membrane, respectively, especially under conditions of membrane stress. IM30 is involved in thylakoid membrane biogenesis and/or maintenance, where it either stabilizes membranes and/or triggers membrane-fusion processes. These apparently contradicting functions have to be tightly controlled and separated spatiotemporally in chloroplasts and cyanobacteria. IM30's fusogenic activity depends on Mg2+ binding to IM30; yet, it still is unclear how Mg2+-loaded IM30 interacts with membranes and promotes membrane fusion. Here, we show that the interaction of Mg2+ with IM30 results in increased binding of IM30 to native, as well as model, membranes. Via atomic force microscopy in liquid, IM30-induced bilayer defects were observed in solid-supported bilayers in the presence of Mg2+. These structures differ dramatically from the membrane-stabilizing carpet structures that were previously observed in the absence of Mg2+. Thus, Mg2+-induced alterations of the IM30 structure switch the IM30 activity from a membrane-stabilizing to a membrane-destabilizing function, a crucial step in membrane fusion.
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Affiliation(s)
- Benedikt Junglas
- Department of Chemistry, Biochemistry, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Amelie Axt
- Max Planck-Institute for Polymer Research, Mainz, Germany; Institute of Physics, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Carmen Siebenaller
- Department of Chemistry, Biochemistry, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Hilal Sonel
- Department of Chemistry, Biochemistry, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Nadja Hellmann
- Department of Chemistry, Biochemistry, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Stefan A L Weber
- Max Planck-Institute for Polymer Research, Mainz, Germany; Institute of Physics, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Dirk Schneider
- Department of Chemistry, Biochemistry, Johannes Gutenberg University Mainz, Mainz, Germany; Institute of Molecular Physiology, Johannes Gutenberg University Mainz, Mainz, Germany.
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4
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Ohnishi N, Sugimoto M, Kondo H, Shioya KI, Zhang L, Sakamoto W. Distinctive in vitro ATP Hydrolysis Activity of AtVIPP1, a Chloroplastic ESCRT-III Superfamily Protein in Arabidopsis. FRONTIERS IN PLANT SCIENCE 2022; 13:949578. [PMID: 35903241 PMCID: PMC9315428 DOI: 10.3389/fpls.2022.949578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Accepted: 06/20/2022] [Indexed: 06/15/2023]
Abstract
Vesicle-inducing protein in plastid 1 (VIPP1), characteristic to oxygenic photosynthetic organisms, is a membrane-remodeling factor that forms homo-oligomers and functions in thylakoid membrane formation and maintenance. The cyanobacterial VIPP1 structure revealed a monomeric folding pattern similar to that of endosomal sorting complex required for transport (ESCRT) III. Characteristic to VIPP1, however, is its own GTP and ATP hydrolytic activity without canonical domains. In this study, we found that histidine-tagged Arabidopsis VIPP1 (AtVIPP1) hydrolyzed GTP and ATP to produce GDP and ADP in vitro, respectively. Unexpectedly, the observed GTPase and ATPase activities were biochemically distinguishable, because the ATPase was optimized for alkaline conditions and dependent on Ca2+ as well as Mg2+, with a higher affinity for ATP than GTP. We found that a version of AtVIPP1 protein with a mutation in its nucleotide-binding site, as deduced from the cyanobacterial structure, retained its hydrolytic activity, suggesting that Arabidopsis and cyanobacterial VIPP1s have different properties. Negative staining particle analysis showed that AtVIPP1 formed particle or rod structures that differed from those of cyanobacteria and Chlamydomonas. These results suggested that the nucleotide hydrolytic activity and oligomer formation of VIPP1 are common in photosynthetic organisms, whereas their properties differ among species.
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Affiliation(s)
- Norikazu Ohnishi
- Institute for Plant Science and Resources, Okayama University, Kurashiki, Japan
| | - Manabu Sugimoto
- Institute for Plant Science and Resources, Okayama University, Kurashiki, Japan
| | - Hideki Kondo
- Institute for Plant Science and Resources, Okayama University, Kurashiki, Japan
| | - Ken-ichi Shioya
- Institute for Plant Science and Resources, Okayama University, Kurashiki, Japan
| | - Lingang Zhang
- School of Life Sciences, Inner Mongolia University, Hohhot, China
| | - Wataru Sakamoto
- Institute for Plant Science and Resources, Okayama University, Kurashiki, Japan
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5
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Guéguen N, Maréchal E. Origin of cyanobacterial thylakoids via a non-vesicular glycolipid phase transition and their impact on the Great Oxygenation Event. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:2721-2734. [PMID: 35560194 DOI: 10.1093/jxb/erab429] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 09/16/2021] [Indexed: 06/15/2023]
Abstract
The appearance of oxygenic photosynthesis in cyanobacteria is a major event in evolution. It had an irreversible impact on the Earth, promoting the Great Oxygenation Event (GOE) ~2.4 billion years ago. Ancient cyanobacteria predating the GOE were Gloeobacter-type cells lacking thylakoids, which hosted photosystems in their cytoplasmic membrane. The driver of the GOE was proposed to be the transition from unicellular to filamentous cyanobacteria. However, the appearance of thylakoids expanded the photosynthetic surface to such an extent that it introduced a multiplier effect, which would be more coherent with an impact on the atmosphere. Primitive thylakoids self-organize as concentric parietal uninterrupted multilayers. There is no robust evidence for an origin of thylakoids via a vesicular-based scenario. This review reports studies supporting that hexagonal II-forming glucolipids and galactolipids at the periphery of the cytosolic membrane could be turned, within nanoseconds and without any external source of energy, into membrane multilayers. Comparison of lipid biosynthetic pathways shows that ancient cyanobacteria contained only one anionic lamellar-forming lipid, phosphatidylglycerol. The acquisition of sulfoquinovosyldiacylglycerol biosynthesis correlates with thylakoid emergence, possibly enabling sufficient provision of anionic lipids to trigger a hexagonal II-to-lamellar phase transition. With this non-vesicular lipid-phase transition, a framework is also available to re-examine the role of companion proteins in thylakoid biogenesis.
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Affiliation(s)
- Nolwenn Guéguen
- Laboratoire de Physiologie Cellulaire et Végétale; INRAE, CNRS, CEA, Université Grenoble Alpes; IRIG; CEA Grenoble, 17 rue des Martyrs, 38000 Grenoble, France
| | - Eric Maréchal
- Laboratoire de Physiologie Cellulaire et Végétale; INRAE, CNRS, CEA, Université Grenoble Alpes; IRIG; CEA Grenoble, 17 rue des Martyrs, 38000 Grenoble, France
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6
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Liu J, Tassinari M, Souza DP, Naskar S, Noel JK, Bohuszewicz O, Buck M, Williams TA, Baum B, Low HH. Bacterial Vipp1 and PspA are members of the ancient ESCRT-III membrane-remodeling superfamily. Cell 2021; 184:3660-3673.e18. [PMID: 34166615 PMCID: PMC8281802 DOI: 10.1016/j.cell.2021.05.041] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 11/24/2020] [Accepted: 05/25/2021] [Indexed: 12/31/2022]
Abstract
Membrane remodeling and repair are essential for all cells. Proteins that perform these functions include Vipp1/IM30 in photosynthetic plastids, PspA in bacteria, and ESCRT-III in eukaryotes. Here, using a combination of evolutionary and structural analyses, we show that these protein families are homologous and share a common ancient evolutionary origin that likely predates the last universal common ancestor. This homology is evident in cryo-electron microscopy structures of Vipp1 rings from the cyanobacterium Nostoc punctiforme presented over a range of symmetries. Each ring is assembled from rungs that stack and progressively tilt to form dome-shaped curvature. Assembly is facilitated by hinges in the Vipp1 monomer, similar to those in ESCRT-III proteins, which allow the formation of flexible polymers. Rings have an inner lumen that is able to bind and deform membranes. Collectively, these data suggest conserved mechanistic principles that underlie Vipp1, PspA, and ESCRT-III-dependent membrane remodeling across all domains of life.
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Affiliation(s)
- Jiwei Liu
- Department of Infectious Disease, Imperial College, London, UK
| | | | - Diorge P Souza
- MRC Laboratory for Molecular Cell Biology, University College London, London, UK; Division of Cell Biology, MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Souvik Naskar
- Department of Infectious Disease, Imperial College, London, UK
| | - Jeffrey K Noel
- Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | | | - Martin Buck
- Department of Life Sciences, Imperial College, London, UK
| | - Tom A Williams
- School of Biological Sciences, University of Bristol, Bristol, UK
| | - Buzz Baum
- MRC Laboratory for Molecular Cell Biology, University College London, London, UK; Division of Cell Biology, MRC Laboratory of Molecular Biology, Cambridge, UK; Institute for the Physics of Living Systems, University College London, London, UK.
| | - Harry H Low
- Department of Infectious Disease, Imperial College, London, UK.
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7
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Abstract
ESCRT-III proteins, which form filaments that deform, bud, and sever membranes, are found in eukaryotes and some archaea. Three studies in this issue of Cell reveal that PspA and Vipp1 are bacterial and cyanobacterial members of the ESCRT-III superfamily, indicating it is even more ubiquitous and ancient than previously thought.
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Affiliation(s)
- Raunaq A Deo
- National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD 20892, USA
| | - William A Prinz
- National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD 20892, USA.
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8
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Gupta TK, Klumpe S, Gries K, Heinz S, Wietrzynski W, Ohnishi N, Niemeyer J, Spaniol B, Schaffer M, Rast A, Ostermeier M, Strauss M, Plitzko JM, Baumeister W, Rudack T, Sakamoto W, Nickelsen J, Schuller JM, Schroda M, Engel BD. Structural basis for VIPP1 oligomerization and maintenance of thylakoid membrane integrity. Cell 2021; 184:3643-3659.e23. [PMID: 34166613 DOI: 10.1016/j.cell.2021.05.011] [Citation(s) in RCA: 56] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 02/16/2021] [Accepted: 05/10/2021] [Indexed: 12/21/2022]
Abstract
Vesicle-inducing protein in plastids 1 (VIPP1) is essential for the biogenesis and maintenance of thylakoid membranes, which transform light into life. However, it is unknown how VIPP1 performs its vital membrane-remodeling functions. Here, we use cryo-electron microscopy to determine structures of cyanobacterial VIPP1 rings, revealing how VIPP1 monomers flex and interweave to form basket-like assemblies of different symmetries. Three VIPP1 monomers together coordinate a non-canonical nucleotide binding pocket on one end of the ring. Inside the ring's lumen, amphipathic helices from each monomer align to form large hydrophobic columns, enabling VIPP1 to bind and curve membranes. In vivo mutations in these hydrophobic surfaces cause extreme thylakoid swelling under high light, indicating an essential role of VIPP1 lipid binding in resisting stress-induced damage. Using cryo-correlative light and electron microscopy (cryo-CLEM), we observe oligomeric VIPP1 coats encapsulating membrane tubules within the Chlamydomonas chloroplast. Our work provides a structural foundation for understanding how VIPP1 directs thylakoid biogenesis and maintenance.
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Affiliation(s)
- Tilak Kumar Gupta
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Sven Klumpe
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Karin Gries
- Molecular Biotechnology and Systems Biology, Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany
| | - Steffen Heinz
- Department of Molecular Plant Sciences, LMU Munich, 82152 Martinsried, Germany
| | - Wojciech Wietrzynski
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany; Helmholtz Pioneer Campus, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Norikazu Ohnishi
- Institute of Plant Science and Resources, Okayama University, Kurashiki, Okayama 710-0046, Japan
| | - Justus Niemeyer
- Molecular Biotechnology and Systems Biology, Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany
| | - Benjamin Spaniol
- Molecular Biotechnology and Systems Biology, Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany
| | - Miroslava Schaffer
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Anna Rast
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany; Department of Molecular Plant Sciences, LMU Munich, 82152 Martinsried, Germany
| | - Matthias Ostermeier
- Department of Molecular Plant Sciences, LMU Munich, 82152 Martinsried, Germany
| | - Mike Strauss
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC H3A 17C, Canada
| | - Jürgen M Plitzko
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Wolfgang Baumeister
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Till Rudack
- Biospectroscopy, Center for Protein Diagnostics (PRODI), Ruhr University Bochum, 44801 Bochum, Germany; Department of Biophysics, Faculty of Biology & Biotechnology, Ruhr University Bochum, 44780 Bochum, Germany
| | - Wataru Sakamoto
- Institute of Plant Science and Resources, Okayama University, Kurashiki, Okayama 710-0046, Japan
| | - Jörg Nickelsen
- Department of Molecular Plant Sciences, LMU Munich, 82152 Martinsried, Germany
| | - Jan M Schuller
- SYNMIKRO Research Center and Department of Chemistry, Philipps-University Marburg, 35032 Marburg, Germany.
| | - Michael Schroda
- Molecular Biotechnology and Systems Biology, Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany.
| | - Benjamin D Engel
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany; Helmholtz Pioneer Campus, Helmholtz Zentrum München, 85764 Neuherberg, Germany; Department of Chemistry, Technical University of Munich, 85748 Garching, Germany.
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9
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Junglas B, Huber ST, Heidler T, Schlösser L, Mann D, Hennig R, Clarke M, Hellmann N, Schneider D, Sachse C. PspA adopts an ESCRT-III-like fold and remodels bacterial membranes. Cell 2021; 184:3674-3688.e18. [PMID: 34166616 DOI: 10.1016/j.cell.2021.05.042] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 03/01/2021] [Accepted: 05/26/2021] [Indexed: 12/31/2022]
Abstract
PspA is the main effector of the phage shock protein (Psp) system and preserves the bacterial inner membrane integrity and function. Here, we present the 3.6 Å resolution cryoelectron microscopy (cryo-EM) structure of PspA assembled in helical rods. PspA monomers adopt a canonical ESCRT-III fold in an extended open conformation. PspA rods are capable of enclosing lipids and generating positive membrane curvature. Using cryo-EM, we visualized how PspA remodels membrane vesicles into μm-sized structures and how it mediates the formation of internalized vesicular structures. Hotspots of these activities are zones derived from PspA assemblies, serving as lipid transfer platforms and linking previously separated lipid structures. These membrane fusion and fission activities are in line with the described functional properties of bacterial PspA/IM30/LiaH proteins. Our structural and functional analyses reveal that bacterial PspA belongs to the evolutionary ancestry of ESCRT-III proteins involved in membrane remodeling.
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Affiliation(s)
- Benedikt Junglas
- Ernst-Ruska Centre for Microscopy and Spectroscopy with Electrons, ER-C-3/Structural Biology, Forschungszentrum Jülich, 52425 Jülich, Germany; JuStruct: Jülich Center for Structural Biology, Forschungszentrum Jülich, 52425 Jülich, Germany; Department of Chemistry, Biochemistry, Johannes Gutenberg University Mainz, 55128 Mainz, Germany
| | - Stefan T Huber
- European Molecular Biology Laboratory (EMBL), Structural and Computational Biology Unit, Meyerhofstraße 1, 69117 Heidelberg, Germany
| | - Thomas Heidler
- Ernst-Ruska Centre for Microscopy and Spectroscopy with Electrons, ER-C-3/Structural Biology, Forschungszentrum Jülich, 52425 Jülich, Germany; JuStruct: Jülich Center for Structural Biology, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Lukas Schlösser
- Department of Chemistry, Biochemistry, Johannes Gutenberg University Mainz, 55128 Mainz, Germany
| | - Daniel Mann
- Ernst-Ruska Centre for Microscopy and Spectroscopy with Electrons, ER-C-3/Structural Biology, Forschungszentrum Jülich, 52425 Jülich, Germany; JuStruct: Jülich Center for Structural Biology, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Raoul Hennig
- Department of Chemistry, Biochemistry, Johannes Gutenberg University Mainz, 55128 Mainz, Germany
| | - Mairi Clarke
- European Molecular Biology Laboratory (EMBL), Structural and Computational Biology Unit, Meyerhofstraße 1, 69117 Heidelberg, Germany
| | - Nadja Hellmann
- Department of Chemistry, Biochemistry, Johannes Gutenberg University Mainz, 55128 Mainz, Germany
| | - Dirk Schneider
- Department of Chemistry, Biochemistry, Johannes Gutenberg University Mainz, 55128 Mainz, Germany; Institute of Molecular Physiology, Johannes Gutenberg University Mainz, 55128 Mainz, Germany.
| | - Carsten Sachse
- Ernst-Ruska Centre for Microscopy and Spectroscopy with Electrons, ER-C-3/Structural Biology, Forschungszentrum Jülich, 52425 Jülich, Germany; JuStruct: Jülich Center for Structural Biology, Forschungszentrum Jülich, 52425 Jülich, Germany; Department of Biology, Heinrich Heine University, Universitätsstr. 1, 40225 Düsseldorf, Germany.
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10
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Siebenaller C, Schlösser L, Junglas B, Schmidt-Dengler M, Jacob D, Hellmann N, Sachse C, Helm M, Schneider D. Binding and/or hydrolysis of purine-based nucleotides is not required for IM30 ring formation. FEBS Lett 2021; 595:1876-1885. [PMID: 34060653 DOI: 10.1002/1873-3468.14140] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 04/30/2021] [Accepted: 05/20/2021] [Indexed: 11/09/2022]
Abstract
IM30, the inner membrane-associated protein of 30 kDa, is conserved in cyanobacteria and chloroplasts. Although its exact physiological function is still mysterious, IM30 is clearly essential for thylakoid membrane biogenesis and/or dynamics. Recently, a cryptic IM30 GTPase activity has been reported, albeit thus far no physiological function has been attributed to this. Yet, it is still possible that GTP binding/hydrolysis affects formation of the prototypical large homo-oligomeric IM30 ring and rod structures. Here, we show that the Synechocystis sp. PCC 6803 IM30 protein in fact is an NTPase that hydrolyzes GTP and ATP, but not CTP or UTP, with about identical rates. While IM30 forms large oligomeric ring complexes, nucleotide binding and/or hydrolysis are clearly not required for ring formation.
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Affiliation(s)
- Carmen Siebenaller
- Department of Chemistry, Biochemistry, Johannes Gutenberg University Mainz, Germany
| | - Lukas Schlösser
- Department of Chemistry, Biochemistry, Johannes Gutenberg University Mainz, Germany
| | - Benedikt Junglas
- Department of Chemistry, Biochemistry, Johannes Gutenberg University Mainz, Germany.,Ernst-Ruska Centre for Microscopy and Spectroscopy with Electrons (ER-C-3/Structural Biology), Forschungszentrum Jülich, Germany.,JuStruct: Jülich Center for Structural Biology, Forschungszentrum Jülich, Germany
| | - Martina Schmidt-Dengler
- Institute for Pharmaceutical and Biomedical Sciences, Johannes Gutenberg University Mainz, Germany
| | - Dominik Jacob
- Institute for Pharmaceutical and Biomedical Sciences, Johannes Gutenberg University Mainz, Germany
| | - Nadja Hellmann
- Department of Chemistry, Biochemistry, Johannes Gutenberg University Mainz, Germany
| | - Carsten Sachse
- Ernst-Ruska Centre for Microscopy and Spectroscopy with Electrons (ER-C-3/Structural Biology), Forschungszentrum Jülich, Germany.,JuStruct: Jülich Center for Structural Biology, Forschungszentrum Jülich, Germany
| | - Mark Helm
- Institute for Pharmaceutical and Biomedical Sciences, Johannes Gutenberg University Mainz, Germany
| | - Dirk Schneider
- Department of Chemistry, Biochemistry, Johannes Gutenberg University Mainz, Germany.,Institute of Molecular Physiology, Johannes Gutenberg University Mainz, Germany
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11
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Huokko T, Ni T, Dykes GF, Simpson DM, Brownridge P, Conradi FD, Beynon RJ, Nixon PJ, Mullineaux CW, Zhang P, Liu LN. Probing the biogenesis pathway and dynamics of thylakoid membranes. Nat Commun 2021; 12:3475. [PMID: 34108457 PMCID: PMC8190092 DOI: 10.1038/s41467-021-23680-1] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 05/11/2021] [Indexed: 01/30/2023] Open
Abstract
How thylakoid membranes are generated to form a metabolically active membrane network and how thylakoid membranes orchestrate the insertion and localization of protein complexes for efficient electron flux remain elusive. Here, we develop a method to modulate thylakoid biogenesis in the rod-shaped cyanobacterium Synechococcus elongatus PCC 7942 by modulating light intensity during cell growth, and probe the spatial-temporal stepwise biogenesis process of thylakoid membranes in cells. Our results reveal that the plasma membrane and regularly arranged concentric thylakoid layers have no physical connections. The newly synthesized thylakoid membrane fragments emerge between the plasma membrane and pre-existing thylakoids. Photosystem I monomers appear in the thylakoid membranes earlier than other mature photosystem assemblies, followed by generation of Photosystem I trimers and Photosystem II complexes. Redistribution of photosynthetic complexes during thylakoid biogenesis ensures establishment of the spatial organization of the functional thylakoid network. This study provides insights into the dynamic biogenesis process and maturation of the functional photosynthetic machinery.
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Affiliation(s)
- Tuomas Huokko
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, UK
| | - Tao Ni
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Gregory F Dykes
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, UK
| | - Deborah M Simpson
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, UK
| | - Philip Brownridge
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, UK
| | - Fabian D Conradi
- School of Biological and Chemical Sciences, Queen Mary University of London, London, UK
| | - Robert J Beynon
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, UK
| | - Peter J Nixon
- Department of Life Sciences, Imperial College London, London, UK
| | - Conrad W Mullineaux
- School of Biological and Chemical Sciences, Queen Mary University of London, London, UK
| | - Peijun Zhang
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
- Electron Bio-Imaging Centre, Diamond Light Source, Harwell Science and Innovation Campus, Didcot, UK
| | - Lu-Ning Liu
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, UK.
- College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China.
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12
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Willdigg JR, Helmann JD. Mini Review: Bacterial Membrane Composition and Its Modulation in Response to Stress. Front Mol Biosci 2021; 8:634438. [PMID: 34046426 PMCID: PMC8144471 DOI: 10.3389/fmolb.2021.634438] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Accepted: 04/13/2021] [Indexed: 11/13/2022] Open
Abstract
Antibiotics and other agents that perturb the synthesis or integrity of the bacterial cell envelope trigger compensatory stress responses. Focusing on Bacillus subtilis as a model system, this mini-review summarizes current views of membrane structure and insights into how cell envelope stress responses remodel and protect the membrane. Altering the composition and properties of the membrane and its associated proteome can protect cells against detergents, antimicrobial peptides, and pore-forming compounds while also, indirectly, contributing to resistance against compounds that affect cell wall synthesis. Many of these regulatory responses are broadly conserved, even where the details of regulation may differ, and can be important in the emergence of antibiotic resistance in clinical settings.
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Affiliation(s)
| | - John D. Helmann
- Department of Microbiology, Cornell University, Ithaca, NY, United States
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13
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Sangphukieo A, Laomettachit T, Ruengjitchatchawalya M. PhotoModPlus: A web server for photosynthetic protein prediction from genome neighborhood features. PLoS One 2021; 16:e0248682. [PMID: 33730083 PMCID: PMC7968678 DOI: 10.1371/journal.pone.0248682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 03/03/2021] [Indexed: 11/20/2022] Open
Abstract
A new web server called PhotoModPlus is presented as a platform for predicting photosynthetic proteins via genome neighborhood networks (GNN) and genome neighborhood-based machine learning. GNN enables users to visualize the overview of the conserved neighboring genes from multiple photosynthetic prokaryotic genomes and provides functional guidance on the query input. In the platform, we also present a new machine learning model utilizing genome neighborhood features for predicting photosynthesis-specific functions based on 24 prokaryotic photosynthesis-related GO terms, namely PhotoModGO. The new model performed better than the sequence-based approaches with an F1 measure of 0.872, based on nested five-fold cross-validation. Finally, we demonstrated the applications of the webserver and the new model in the identification of novel photosynthetic proteins. The server is user-friendly, compatible with all devices, and available at bicep.kmutt.ac.th/photomod.
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Affiliation(s)
- Apiwat Sangphukieo
- Bioinformatics and Systems Biology Program, School of Bioresources and Technology, King Mongkut’s University of Technology Thonburi (KMUTT), Bang Khun Thian, Bangkok, Thailand
- School of Information Technology, KMUTT, Thung Khru, Bangkok, Thailand
| | - Teeraphan Laomettachit
- Bioinformatics and Systems Biology Program, School of Bioresources and Technology, King Mongkut’s University of Technology Thonburi (KMUTT), Bang Khun Thian, Bangkok, Thailand
| | - Marasri Ruengjitchatchawalya
- Bioinformatics and Systems Biology Program, School of Bioresources and Technology, King Mongkut’s University of Technology Thonburi (KMUTT), Bang Khun Thian, Bangkok, Thailand
- Biotechnology Program, School of Bioresources and Technology, KMUTT, Bang Khun Thian, Bangkok, Thailand
- Algal Biotechnology Research Group, Pilot Plant Development and Training Institute, KMUTT, Bang Khun Thian, Bangkok, Thailand
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14
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Junglas B, Orru R, Axt A, Siebenaller C, Steinchen W, Heidrich J, Hellmich UA, Hellmann N, Wolf E, Weber SAL, Schneider D. IM30 IDPs form a membrane-protective carpet upon super-complex disassembly. Commun Biol 2020; 3:595. [PMID: 33087858 PMCID: PMC7577978 DOI: 10.1038/s42003-020-01314-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 09/22/2020] [Indexed: 12/26/2022] Open
Abstract
Members of the phage shock protein A (PspA) family, including the inner membrane-associated protein of 30 kDa (IM30), are suggested to stabilize stressed cellular membranes. Furthermore, IM30 is essential in thylakoid membrane-containing chloroplasts and cyanobacteria, where it is involved in membrane biogenesis and/or remodeling. While it is well known that PspA and IM30 bind to membranes, the mechanism of membrane stabilization is still enigmatic. Here we report that ring-shaped IM30 super-complexes disassemble on membranes, resulting in formation of a membrane-protecting protein carpet. Upon ring dissociation, the C-terminal domain of IM30 unfolds, and the protomers self-assemble on membranes. IM30 assemblies at membranes have been observed before in vivo and were associated with stress response in cyanobacteria and chloroplasts. These assemblies likely correspond to the here identified carpet structures. Our study defines the thus far enigmatic structural basis for the physiological function of IM30 and related proteins, including PspA, and highlights a hitherto unrecognized concept of membrane stabilization by intrinsically disordered proteins.
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Affiliation(s)
- Benedikt Junglas
- Department of Chemistry, Biochemistry, Johannes Gutenberg University Mainz, 55128, Mainz, Germany
| | - Roberto Orru
- Institute of Molecular Physiology, Johannes Gutenberg University Mainz, 55128, Mainz, Germany
| | - Amelie Axt
- Max Planck-Institute for Polymer Research, 55128, Mainz, Germany
- Institute of Physics, Johannes Gutenberg University Mainz, 55099, Mainz, Germany
| | - Carmen Siebenaller
- Department of Chemistry, Biochemistry, Johannes Gutenberg University Mainz, 55128, Mainz, Germany
| | - Wieland Steinchen
- Philipps-University Marburg, Center for Synthetic Microbiology (SYNMIKRO) and Department of Chemistry, 35032, Marburg, Germany
| | - Jennifer Heidrich
- Department of Chemistry, Biochemistry, Johannes Gutenberg University Mainz, 55128, Mainz, Germany
| | - Ute A Hellmich
- Department of Chemistry, Biochemistry, Johannes Gutenberg University Mainz, 55128, Mainz, Germany
- Centre for Biomolecular Magnetic Resonance (BMRZ), Goethe-University Frankfurt, 60438, Frankfurt, Germany
| | - Nadja Hellmann
- Department of Chemistry, Biochemistry, Johannes Gutenberg University Mainz, 55128, Mainz, Germany
| | - Eva Wolf
- Institute of Molecular Physiology, Johannes Gutenberg University Mainz, 55128, Mainz, Germany
- Institute of Molecular Biology (IMB), 55128, Mainz, Germany
| | - Stefan A L Weber
- Max Planck-Institute for Polymer Research, 55128, Mainz, Germany
- Institute of Physics, Johannes Gutenberg University Mainz, 55099, Mainz, Germany
| | - Dirk Schneider
- Department of Chemistry, Biochemistry, Johannes Gutenberg University Mainz, 55128, Mainz, Germany.
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15
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Siebenaller C, Junglas B, Lehmann A, Hellmann N, Schneider D. Proton Leakage Is Sensed by IM30 and Activates IM30-Triggered Membrane Fusion. Int J Mol Sci 2020; 21:E4530. [PMID: 32630559 PMCID: PMC7350238 DOI: 10.3390/ijms21124530] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 06/19/2020] [Accepted: 06/23/2020] [Indexed: 12/19/2022] Open
Abstract
The inner membrane-associated protein of 30 kDa (IM30) is crucial for the development and maintenance of the thylakoid membrane system in chloroplasts and cyanobacteria. While its exact physiological function still is under debate, it has recently been suggested that IM30 has (at least) a dual function, and the protein is involved in stabilization of the thylakoid membrane as well as in Mg2+-dependent membrane fusion. IM30 binds to negatively charged membrane lipids, preferentially at stressed membrane regions where protons potentially leak out from the thylakoid lumen into the chloroplast stroma or the cyanobacterial cytoplasm, respectively. Here we show in vitro that IM30 membrane binding, as well as membrane fusion, is strongly increased in acidic environments. This enhanced activity involves a rearrangement of the protein structure. We suggest that this acid-induced transition is part of a mechanism that allows IM30 to (i) sense sites of proton leakage at the thylakoid membrane, to (ii) preferentially bind there, and to (iii) seal leaky membrane regions via membrane fusion processes.
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Affiliation(s)
| | | | | | | | - Dirk Schneider
- Department of Chemistry, Biochemistry, Johannes Gutenberg University Mainz, 55128 Mainz, Germany; (C.S.); (B.J.); (A.L.); (N.H.)
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16
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Lundquist PK, Shivaiah KK, Espinoza-Corral R. Lipid droplets throughout the evolutionary tree. Prog Lipid Res 2020; 78:101029. [PMID: 32348789 DOI: 10.1016/j.plipres.2020.101029] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2020] [Revised: 04/11/2020] [Accepted: 04/18/2020] [Indexed: 12/11/2022]
Abstract
Intracellular lipid droplets are utilized for lipid storage and metabolism in organisms as evolutionarily diverse as animals, fungi, plants, bacteria, and archaea. These lipid droplets demonstrate great diversity in biological functions and protein and lipid compositions, yet fundamentally share common molecular and ultrastructural characteristics. Lipid droplet research has been largely fragmented across the diversity of lipid droplet classes and sub-classes. However, we suggest that there is great potential benefit to the lipid community in better integrating the lipid droplet research fields. To facilitate such integration, we survey the protein and lipid compositions, functional roles, and mechanisms of biogenesis across the breadth of lipid droplets studied throughout the natural world. We depict the big picture of lipid droplet biology, emphasizing shared characteristics and unique differences seen between different classes. In presenting the known diversity of lipid droplets side-by-side it becomes necessary to offer for the first time a consistent system of categorization and nomenclature. We propose a division into three primary classes that reflect their sub-cellular location: i) cytoplasmic lipid droplets (CYTO-LDs), that are present in the eukaryotic cytoplasm, ii) prokaryotic lipid droplets (PRO-LDs), that exist in the prokaryotic cytoplasm, and iii) plastid lipid droplets (PL-LDs), that are found in plant plastids, organelles of photosynthetic eukaryotes. Within each class there is a remarkable array of sub-classes displaying various sizes, shapes and compositions. A more integrated lipid droplet research field will provide opportunities to better build on discoveries and accelerate the pace of research in ways that have not been possible.
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Affiliation(s)
- Peter K Lundquist
- Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, MI 48824, USA; Plant Resilience Institute, Michigan State University, East Lansing, MI, 48824, USA.
| | - Kiran-Kumar Shivaiah
- Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, MI 48824, USA; Plant Resilience Institute, Michigan State University, East Lansing, MI, 48824, USA
| | - Roberto Espinoza-Corral
- Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, MI 48824, USA; Plant Resilience Institute, Michigan State University, East Lansing, MI, 48824, USA
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17
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Siebenaller C, Junglas B, Schneider D. Functional Implications of Multiple IM30 Oligomeric States. FRONTIERS IN PLANT SCIENCE 2019; 10:1500. [PMID: 31824532 PMCID: PMC6882379 DOI: 10.3389/fpls.2019.01500] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 10/29/2019] [Indexed: 05/03/2023]
Abstract
The inner membrane-associated protein of 30 kDa (IM30), also known as the vesicle-inducing protein in plastids 1 (Vipp1), is essential for photo-autotrophic growth of cyanobacteria, algae and higher plants. While its exact function still remains largely elusive, it is commonly accepted that IM30 is crucially involved in thylakoid membrane biogenesis, stabilization and/or maintenance. A characteristic feature of IM30 is its intrinsic propensity to form large homo-oligomeric protein complexes. 15 years ago, it has been reported that these supercomplexes have a ring-shaped structure. However, the in vivo significance of these ring structures is not finally resolved yet and the formation of more complex assemblies has been reported. We here present and discuss research on IM30 conducted within the past 25 years with a special emphasis on the question of why we potentially need IM30 supercomplexes in vivo.
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Affiliation(s)
| | | | - Dirk Schneider
- Department of Pharmacy and Biochemistry, Johannes Gutenberg University Mainz, Mainz, Germany
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18
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VIPP1 rods engulf membranes containing phosphatidylinositol phosphates. Sci Rep 2019; 9:8725. [PMID: 31217458 PMCID: PMC6584618 DOI: 10.1038/s41598-019-44259-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2018] [Accepted: 05/14/2019] [Indexed: 12/15/2022] Open
Abstract
In cyanobacteria and plants, VIPP1 plays crucial roles in the biogenesis and repair of thylakoid membrane protein complexes and in coping with chloroplast membrane stress. In chloroplasts, VIPP1 localizes in distinct patterns at or close to envelope and thylakoid membranes. In vitro, VIPP1 forms higher-order oligomers of >1 MDa that organize into rings and rods. However, it remains unknown how VIPP1 oligomerization is related to function. Using time-resolved fluorescence anisotropy and sucrose density gradient centrifugation, we show here that Chlamydomonas reinhardtii VIPP1 binds strongly to liposomal membranes containing phosphatidylinositol-4-phosphate (PI4P). Cryo-electron tomography reveals that VIPP1 oligomerizes into rods that can engulf liposomal membranes containing PI4P. These findings place VIPP1 into a group of membrane-shaping proteins including epsin and BAR domain proteins. Moreover, they point to a potential role of phosphatidylinositols in directing the shaping of chloroplast membranes.
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19
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Rast A, Schaffer M, Albert S, Wan W, Pfeffer S, Beck F, Plitzko JM, Nickelsen J, Engel BD. Biogenic regions of cyanobacterial thylakoids form contact sites with the plasma membrane. NATURE PLANTS 2019; 5:436-446. [PMID: 30962530 DOI: 10.1038/s41477-019-0399-7] [Citation(s) in RCA: 75] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 03/04/2019] [Indexed: 05/20/2023]
Abstract
Little is known about how the photosynthetic machinery is arranged in time and space during the biogenesis of thylakoid membranes. Using in situ cryo-electron tomography to image the three-dimensional architecture of the cyanobacterium Synechocystis, we observed that the tips of multiple thylakoids merge to form a substructure called the 'convergence membrane'. This high-curvature membrane comes into close contact with the plasma membrane at discrete sites. We generated subtomogram averages of 70S ribosomes and array-forming phycobilisomes, then mapped these structures onto the native membrane architecture as markers for protein synthesis and photosynthesis, respectively. This molecular localization identified two distinct biogenic regions in the thylakoid network: thylakoids facing the cytosolic interior of the cell that were associated with both marker complexes, and convergence membranes that were decorated by ribosomes but not phycobilisomes. We propose that the convergence membranes perform a specialized biogenic function, coupling the synthesis of thylakoid proteins with the integration of cofactors from the plasma membrane and the periplasmic space.
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Affiliation(s)
- Anna Rast
- Department of Molecular Plant Sciences, Ludwig-Maximilians-University Munich, Martinsried, Germany
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Miroslava Schaffer
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Sahradha Albert
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - William Wan
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Stefan Pfeffer
- Center for Molecular Biology, University of Heidelberg, Heidelberg, Germany
| | - Florian Beck
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Jürgen M Plitzko
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Jörg Nickelsen
- Department of Molecular Plant Sciences, Ludwig-Maximilians-University Munich, Martinsried, Germany.
| | - Benjamin D Engel
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried, Germany.
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20
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Abstract
Direct membrane fusion in chloroplasts and cyanobacteria is triggered by IM30 protein oligomers, but so far the exact mechanism of membrane binding has remained obscure. In this issue of Structure, Saur et al. (2017) describe the detailed structure of Janus-faced IM30 rings crucial for thylakoid membrane fusion and membrane layer architecture.
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Affiliation(s)
- Diana Wolf
- Institute of Microbiology, Technische Universität Dresden, 01217 Dresden, Germany.
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21
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Thurotte A, Schneider D. The Fusion Activity of IM30 Rings Involves Controlled Unmasking of the Fusogenic Core. FRONTIERS IN PLANT SCIENCE 2019; 10:108. [PMID: 30792728 PMCID: PMC6374351 DOI: 10.3389/fpls.2019.00108] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 01/23/2019] [Indexed: 05/20/2023]
Abstract
The inner membrane-associated protein of 30 kDa (IM30, also known as Vipp1) is required for thylakoid membrane biogenesis and maintenance in cyanobacteria and chloroplasts. The protein forms large rings of ∼2 MDa and triggers membrane fusion in presence of Mg2+. Based on the here presented observations, IM30 rings are built from dimers of dimers, and formation of these tetrameric building blocks is driven by interactions of the central coiled-coil, formed by helices 2 and 3, and stabilized via additional interactions mainly involving helix 1. Furthermore, helix 1 as well as C-terminal regions of IM30 together negatively regulate ring-ring contacts. We propose that IM30 rings represent the inactive form of IM30, and upon binding to negatively charged membrane surfaces, the here identified fusogenic core of IM30 rings eventually interacts with the lipid bilayer, resulting in membrane destabilization and membrane fusion. Unmasking of the IM30 fusogenic core likely is controlled by Mg2+, which triggers rearrangement of the IM30 ring structure.
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22
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Heidrich J, Junglas B, Grytsyk N, Hellmann N, Rusitzka K, Gebauer W, Markl J, Hellwig P, Schneider D. Mg 2+ binding triggers rearrangement of the IM30 ring structure, resulting in augmented exposure of hydrophobic surfaces competent for membrane binding. J Biol Chem 2018; 293:8230-8241. [PMID: 29618510 DOI: 10.1074/jbc.ra117.000991] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 03/20/2018] [Indexed: 12/24/2022] Open
Abstract
The "inner membrane-associated protein of 30 kDa" (IM30), also known as "vesicle-inducing protein in plastids 1" (Vipp1), is found in the majority of photosynthetic organisms that use oxygen as an energy source, and its occurrence appears to be coupled to the existence of thylakoid membranes in cyanobacteria and chloroplasts. IM30 is most likely involved in thylakoid membrane biogenesis and/or maintenance, and has recently been shown to function as a membrane fusion protein in presence of Mg2+ However, the precise role of Mg2+ in this process and its impact on the structure and function of IM30 remains unknown. Here, we show that Mg2+ binds directly to IM30 with a binding affinity of ∼1 mm Mg2+ binding compacts the IM30 structure coupled with an increase in the thermodynamic stability of the proteins' secondary, tertiary, and quaternary structures. Furthermore, the structural alterations trigger IM30 double ring formation in vitro because of increased exposure of hydrophobic surface regions. However, in vivo Mg2+-triggered exposure of hydrophobic surface regions most likely modulates membrane binding and induces membrane fusion.
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Affiliation(s)
- Jennifer Heidrich
- Institut für Pharmazie und Biochemie, Johannes-Gutenberg-Universität Mainz, 55128 Mainz, Germany
| | - Benedikt Junglas
- Institut für Pharmazie und Biochemie, Johannes-Gutenberg-Universität Mainz, 55128 Mainz, Germany
| | - Natalia Grytsyk
- Laboratoire de bioelectrochimie et spectroscopie, UMR 7140, CNRS Université de Strasbourg, 1 rue Blaise Pascal, 67000 Strasbourg, Germany
| | - Nadja Hellmann
- Institut für Pharmazie und Biochemie, Johannes-Gutenberg-Universität Mainz, 55128 Mainz, Germany
| | - Kristiane Rusitzka
- Institut für Molekulare Physiologie, Johannes Gutenberg-Universität Mainz, 55128 Mainz, Germany
| | - Wolfgang Gebauer
- Institut für Molekulare Physiologie, Johannes Gutenberg-Universität Mainz, 55128 Mainz, Germany
| | - Jürgen Markl
- Institut für Molekulare Physiologie, Johannes Gutenberg-Universität Mainz, 55128 Mainz, Germany
| | - Petra Hellwig
- Laboratoire de bioelectrochimie et spectroscopie, UMR 7140, CNRS Université de Strasbourg, 1 rue Blaise Pascal, 67000 Strasbourg, Germany
| | - Dirk Schneider
- Institut für Pharmazie und Biochemie, Johannes-Gutenberg-Universität Mainz, 55128 Mainz, Germany.
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23
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24
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Affiliation(s)
- Benedikt Junglas
- Institut für Pharmazie und Biochemie; Johannes Gutenberg-Universität Mainz; Mainz Germany
| | - Dirk Schneider
- Institut für Pharmazie und Biochemie; Johannes Gutenberg-Universität Mainz; Mainz Germany
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