1
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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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2
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Cyanobacterial membrane dynamics in the light of eukaryotic principles. Biosci Rep 2023; 43:232406. [PMID: 36602300 PMCID: PMC9950537 DOI: 10.1042/bsr20221269] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 12/23/2022] [Accepted: 01/03/2023] [Indexed: 01/06/2023] Open
Abstract
Intracellular compartmentalization is a hallmark of eukaryotic cells. Dynamic membrane remodeling, involving membrane fission/fusion events, clearly is crucial for cell viability and function, as well as membrane stabilization and/or repair, e.g., during or after injury. In recent decades, several proteins involved in membrane stabilization and/or dynamic membrane remodeling have been identified and described in eukaryotes. Yet, while typically not having a cellular organization as complex as eukaryotes, also bacteria can contain extra internal membrane systems besides the cytoplasmic membranes (CMs). Thus, also in bacteria mechanisms must have evolved to stabilize membranes and/or trigger dynamic membrane remodeling processes. In fact, in recent years proteins, which were initially defined being eukaryotic inventions, have been recognized also in bacteria, and likely these proteins shape membranes also in these organisms. One example of a complex prokaryotic inner membrane system is the thylakoid membrane (TM) of cyanobacteria, which contains the complexes of the photosynthesis light reaction. Cyanobacteria are evolutionary closely related to chloroplasts, and extensive remodeling of the internal membrane systems has been observed in chloroplasts and cyanobacteria during membrane biogenesis and/or at changing light conditions. We here discuss common principles guiding eukaryotic and prokaryotic membrane dynamics and the proteins involved, with a special focus on the dynamics of the cyanobacterial TMs and CMs.
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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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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: 42] [Impact Index Per Article: 14.0] [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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5
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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: 45] [Impact Index Per Article: 15.0] [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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6
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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: 27] [Impact Index Per Article: 9.0] [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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7
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Santhanagopalan I, Wong R, Mathur T, Griffiths H. Orchestral manoeuvres in the light: crosstalk needed for regulation of the Chlamydomonas carbon concentration mechanism. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:4604-4624. [PMID: 33893473 PMCID: PMC8320531 DOI: 10.1093/jxb/erab169] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 04/19/2021] [Indexed: 05/19/2023]
Abstract
The inducible carbon concentration mechanism (CCM) in Chlamydomonas reinhardtii has been well defined from a molecular and ultrastructural perspective. Inorganic carbon transport proteins, and strategically located carbonic anhydrases deliver CO2 within the chloroplast pyrenoid matrix where Rubisco is packaged. However, there is little understanding of the fundamental signalling and sensing processes leading to CCM induction. While external CO2 limitation has been believed to be the primary cue, the coupling between energetic supply and inorganic carbon demand through regulatory feedback from light harvesting and photorespiration signals could provide the original CCM trigger. Key questions regarding the integration of these processes are addressed in this review. We consider how the chloroplast functions as a crucible for photosynthesis, importing and integrating nuclear-encoded components from the cytoplasm, and sending retrograde signals to the nucleus to regulate CCM induction. We hypothesize that induction of the CCM is associated with retrograde signals associated with photorespiration and/or light stress. We have also examined the significance of common evolutionary pressures for origins of two co-regulated processes, namely the CCM and photorespiration, in addition to identifying genes of interest involved in transcription, protein folding, and regulatory processes which are needed to fully understand the processes leading to CCM induction.
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Affiliation(s)
- Indu Santhanagopalan
- Department of Plant Sciences, Downing Street, University of Cambridge, Cambridge, UK
| | - Rachel Wong
- Department of Plant Sciences, Downing Street, University of Cambridge, Cambridge, UK
| | - Tanya Mathur
- Department of Plant Sciences, Downing Street, University of Cambridge, Cambridge, UK
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8
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Messant M, Krieger-Liszkay A, Shimakawa G. Dynamic Changes in Protein-Membrane Association for Regulating Photosynthetic Electron Transport. Cells 2021; 10:cells10051216. [PMID: 34065690 PMCID: PMC8155901 DOI: 10.3390/cells10051216] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 05/13/2021] [Accepted: 05/13/2021] [Indexed: 01/08/2023] Open
Abstract
Photosynthesis has to work efficiently in contrasting environments such as in shade and full sun. Rapid changes in light intensity and over-reduction of the photosynthetic electron transport chain cause production of reactive oxygen species, which can potentially damage the photosynthetic apparatus. Thus, to avoid such damage, photosynthetic electron transport is regulated on many levels, including light absorption in antenna, electron transfer reactions in the reaction centers, and consumption of ATP and NADPH in different metabolic pathways. Many regulatory mechanisms involve the movement of protein-pigment complexes within the thylakoid membrane. Furthermore, a certain number of chloroplast proteins exist in different oligomerization states, which temporally associate to the thylakoid membrane and modulate their activity. This review starts by giving a short overview of the lipid composition of the chloroplast membranes, followed by describing supercomplex formation in cyclic electron flow. Protein movements involved in the various mechanisms of non-photochemical quenching, including thermal dissipation, state transitions and the photosystem II damage–repair cycle are detailed. We highlight the importance of changes in the oligomerization state of VIPP and of the plastid terminal oxidase PTOX and discuss the factors that may be responsible for these changes. Photosynthesis-related protein movements and organization states of certain proteins all play a role in acclimation of the photosynthetic organism to the environment.
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Affiliation(s)
- Marine Messant
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, CEDEX, 91198 Gif-sur-Yvette, France;
| | - Anja Krieger-Liszkay
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, CEDEX, 91198 Gif-sur-Yvette, France;
- Correspondence:
| | - Ginga Shimakawa
- Research Center for Solar Energy Chemistry, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan;
- Department of Bioscience, School of Biological and Environmental Sciences, Kwansei-Gakuin University, 2-1 Gakuen, Sanda, Hyogo 669-1337, Japan
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9
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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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10
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Nymark M, Grønbech Hafskjold MC, Volpe C, Fonseca DDM, Sharma A, Tsirvouli E, Serif M, Winge P, Finazzi G, Bones AM. Functional studies of CpSRP54 in diatoms show that the mechanism of thylakoid protein insertion differs from that in plants and green algae. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 106:113-132. [PMID: 33372269 DOI: 10.1111/tpj.15149] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 12/16/2020] [Accepted: 12/22/2020] [Indexed: 06/12/2023]
Abstract
The chloroplast signal recognition particle 54 kDa (CpSRP54) protein is a member of the CpSRP pathway known to target proteins to thylakoid membranes in plants and green algae. Loss of CpSRP54 in the marine diatom Phaeodactylum tricornutum lowers the accumulation of a selection of chloroplast-encoded subunits of photosynthetic complexes, indicating a role in the co-translational part of the CpSRP pathway. In contrast to plants and green algae, absence of CpSRP54 does not have a negative effect on the content of light-harvesting antenna complex proteins and pigments in P. tricornutum, indicating that the diatom CpSRP54 protein has not evolved to function in the post-translational part of the CpSRP pathway. Cpsrp54 KO mutants display altered photophysiological responses, with a stronger induction of photoprotective mechanisms and lower growth rates compared to wild type when exposed to increased light intensities. Nonetheless, their phenotype is relatively mild, thanks to the activation of mechanisms alleviating the loss of CpSRP54, involving upregulation of chaperones. We conclude that plants, green algae, and diatoms have evolved differences in the pathways for co-translational and post-translational insertion of proteins into the thylakoid membranes.
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Affiliation(s)
- Marianne Nymark
- Department of Biology, Norwegian University of Science and Technology, Trondheim, N-7491, Norway
| | - Marthe Caroline Grønbech Hafskjold
- Department of Biology, Norwegian University of Science and Technology, Trondheim, N-7491, Norway
- Department of Biotechnology and Food Science, Norwegian University of Science and Technology, Trondheim, N-7491, Norway
| | - Charlotte Volpe
- Department of Biotechnology and Food Science, Norwegian University of Science and Technology, Trondheim, N-7491, Norway
| | - Davi de Miranda Fonseca
- Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology, NTNU, Trondheim, N-7491, Norway
- Proteomics and Modomics Experimental Core Facility (PROMEC), NTNU and Central Administration, St Olavs Hospital, The University Hospital in Trondheim, Trondheim, Norway
| | - Animesh Sharma
- Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology, NTNU, Trondheim, N-7491, Norway
- Proteomics and Modomics Experimental Core Facility (PROMEC), NTNU and Central Administration, St Olavs Hospital, The University Hospital in Trondheim, Trondheim, Norway
| | - Eirini Tsirvouli
- Department of Biology, Norwegian University of Science and Technology, Trondheim, N-7491, Norway
| | - Manuel Serif
- Department of Biology, Norwegian University of Science and Technology, Trondheim, N-7491, Norway
| | - Per Winge
- Department of Biology, Norwegian University of Science and Technology, Trondheim, N-7491, Norway
| | - Giovanni Finazzi
- Université Grenoble Alpes (UGA), Laboratoire de Physiologie Cellulaire et Végétale, UMR 5168, Centre National de la Recherche Scientifique (CNRS), Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Interdisciplinary Research Institute of Grenoble (IRIG), CEA-Grenoble, Grenoble, 38000, France
| | - Atle Magnar Bones
- Department of Biology, Norwegian University of Science and Technology, Trondheim, N-7491, Norway
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11
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Willdigg JR, Helmann JD. Mini Review: Bacterial Membrane Composition and Its Modulation in Response to Stress. Front Mol Biosci 2021. [PMID: 34046426 DOI: 10.3389/fmolb.2021.634438/bibtex] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/23/2023] 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)
- Jessica R Willdigg
- Department of Microbiology, Cornell University, Ithaca, NY, United States
| | - John D Helmann
- Department of Microbiology, Cornell University, Ithaca, NY, United States
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12
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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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13
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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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14
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Junglas B, Siebenaller C, Schlösser L, Hellmann N, Schneider D. GTP hydrolysis by Synechocystis IM30 does not decisively affect its membrane remodeling activity. Sci Rep 2020; 10:9793. [PMID: 32555292 PMCID: PMC7299955 DOI: 10.1038/s41598-020-66818-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 05/26/2020] [Indexed: 01/28/2023] Open
Abstract
The function of IM30 (also known as Vipp1) is linked to protection and/or remodeling of the thylakoid membrane system in chloroplasts and cyanobacteria. Recently, it has been revealed that the Arabidopsis IM30 protein exhibits GTP hydrolyzing activity in vitro, which was unexpected, as IM30 does not show any classical GTPase features. In the present study, we addressed the question, whether an apparent GTPase activity is conserved in IM30 proteins and can also be observed for IM30 of the cyanobacterium Synechocystis sp. PCC 6803. We show that Synechocystis IM30 is indeed able to bind and hydrolyze GTP followed by the release of Pi. Yet, the apparent GTPase activity of Synechocystis IM30 does not depend on Mg2+, which, together with the lack of classical GTPase features, renders IM30 an atypical GTPase. To elucidate the impact of this cryptic GTPase activity on the membrane remodeling activity of IM30, we tested whether GTP hydrolysis influences IM30 membrane binding and/or IM30-mediated membrane fusion. We show that membrane remodeling by Synechocystis IM30 is slightly affected by nucleotides. Yet, despite IM30 clearly catalyzing GTP hydrolysis, this does not seem to be vital for its membrane remodeling function.
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Affiliation(s)
- Benedikt Junglas
- Department of Chemistry, Biochemistry, Johannes Gutenberg University Mainz, 55128, Mainz, Germany
| | - Carmen Siebenaller
- Department of Chemistry, Biochemistry, Johannes Gutenberg University Mainz, 55128, Mainz, Germany
| | - Lukas Schlösser
- Department of Chemistry, Biochemistry, Johannes Gutenberg University Mainz, 55128, Mainz, 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.
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15
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Theis J, Niemeyer J, Schmollinger S, Ries F, Rütgers M, Gupta TK, Sommer F, Muranaka LS, Venn B, Schulz-Raffelt M, Willmund F, Engel BD, Schroda M. VIPP2 interacts with VIPP1 and HSP22E/F at chloroplast membranes and modulates a retrograde signal for HSP22E/F gene expression. PLANT, CELL & ENVIRONMENT 2020; 43:1212-1229. [PMID: 31994740 DOI: 10.1111/pce.13732] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 01/22/2020] [Accepted: 01/23/2020] [Indexed: 06/10/2023]
Abstract
VIPP proteins aid thylakoid biogenesis and membrane maintenance in cyanobacteria, algae, and plants. Some members of the Chlorophyceae contain two VIPP paralogs termed VIPP1 and VIPP2, which originate from an early gene duplication event during the evolution of green algae. VIPP2 is barely expressed under nonstress conditions but accumulates in cells exposed to high light intensities or H2 O2 , during recovery from heat stress, and in mutants with defective integration (alb3.1) or translocation (secA) of thylakoid membrane proteins. Recombinant VIPP2 forms rod-like structures in vitro and shows a strong affinity for phosphatidylinositol phosphate. Under stress conditions, >70% of VIPP2 is present in membrane fractions and localizes to chloroplast membranes. A vipp2 knock-out mutant displays no growth phenotypes and no defects in the biogenesis or repair of photosystem II. However, after exposure to high light intensities, the vipp2 mutant accumulates less HSP22E/F and more LHCSR3 protein and transcript. This suggests that VIPP2 modulates a retrograde signal for the expression of nuclear genes HSP22E/F and LHCSR3. Immunoprecipitation of VIPP2 from solubilized cells and membrane-enriched fractions revealed major interactions with VIPP1 and minor interactions with HSP22E/F. Our data support a distinct role of VIPP2 in sensing and coping with chloroplast membrane stress.
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Affiliation(s)
- Jasmine Theis
- Molekulare Biotechnologie & Systembiologie, TU Kaiserslautern, Kaiserslautern, Germany
| | - Justus Niemeyer
- Molekulare Biotechnologie & Systembiologie, TU Kaiserslautern, Kaiserslautern, Germany
| | - Stefan Schmollinger
- Molekulare Biotechnologie & Systembiologie, TU Kaiserslautern, Kaiserslautern, Germany
| | - Fabian Ries
- Molecular Genetics of Eukaryotes, TU Kaiserslautern, Kaiserslautern, Germany
| | - Mark Rütgers
- Molekulare Biotechnologie & Systembiologie, TU Kaiserslautern, Kaiserslautern, Germany
| | - Tilak Kumar Gupta
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Frederik Sommer
- Molekulare Biotechnologie & Systembiologie, TU Kaiserslautern, Kaiserslautern, Germany
| | | | - Benedikt Venn
- Molekulare Biotechnologie & Systembiologie, TU Kaiserslautern, Kaiserslautern, Germany
| | - Miriam Schulz-Raffelt
- Molekulare Biotechnologie & Systembiologie, TU Kaiserslautern, Kaiserslautern, Germany
| | - Felix Willmund
- Molecular Genetics of Eukaryotes, TU Kaiserslautern, Kaiserslautern, Germany
| | - Benjamin D Engel
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Michael Schroda
- Molekulare Biotechnologie & Systembiologie, TU Kaiserslautern, Kaiserslautern, Germany
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16
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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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17
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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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18
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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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19
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Mechela A, Schwenkert S, Soll J. A brief history of thylakoid biogenesis. Open Biol 2019; 9:180237. [PMID: 30958119 PMCID: PMC6367138 DOI: 10.1098/rsob.180237] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Accepted: 01/09/2019] [Indexed: 12/20/2022] Open
Abstract
The thylakoid membrane network inside chloroplasts harbours the protein complexes that are necessary for the light-dependent reactions of photosynthesis. Cellular processes for building and altering this membrane network are therefore essential for life on Earth. Nevertheless, detailed molecular processes concerning the origin and synthesis of the thylakoids remain elusive. Thylakoid biogenesis is strongly coupled to the processes of chloroplast differentiation. Chloroplasts develop from special progenitors called proplastids. As many of the needed building blocks such as lipids and pigments derive from the inner envelope, the question arises how these components are recruited to their target membrane. This review travels back in time to the beginnings of thylakoid membrane research to summarize findings, facts and fictions on thylakoid biogenesis and structure up to the present state, including new insights and future developments in this field.
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Affiliation(s)
- Annabel Mechela
- Department Biologie I, Botanik, Ludwig-Maximilians-Universität, Großhaderner Strasse 2-4, 82152 Planegg-Martinsried, Germany
| | - Serena Schwenkert
- Department Biologie I, Botanik, Ludwig-Maximilians-Universität, Großhaderner Strasse 2-4, 82152 Planegg-Martinsried, Germany
- Munich Center for Integrated Protein Science CiPSM, Ludwig-Maximilians-Universität München, Feodor-Lynen-Strasse 25, 81377 Munich, Germany
| | - Jürgen Soll
- Department Biologie I, Botanik, Ludwig-Maximilians-Universität, Großhaderner Strasse 2-4, 82152 Planegg-Martinsried, Germany
- Munich Center for Integrated Protein Science CiPSM, Ludwig-Maximilians-Universität München, Feodor-Lynen-Strasse 25, 81377 Munich, Germany
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20
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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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21
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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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