1
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Kuklewicz J, Zimmer J. Molecular insights into capsular polysaccharide secretion. Nature 2024; 628:901-909. [PMID: 38570679 PMCID: PMC11041684 DOI: 10.1038/s41586-024-07248-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Accepted: 02/27/2024] [Indexed: 04/05/2024]
Abstract
Capsular polysaccharides (CPSs) fortify the cell boundaries of many commensal and pathogenic bacteria1. Through the ABC-transporter-dependent biosynthesis pathway, CPSs are synthesized intracellularly on a lipid anchor and secreted across the cell envelope by the KpsMT ABC transporter associated with the KpsE and KpsD subunits1,2. Here we use structural and functional studies to uncover crucial steps of CPS secretion in Gram-negative bacteria. We show that KpsMT has broad substrate specificity and is sufficient for the translocation of CPSs across the inner bacterial membrane, and we determine the cell surface organization and localization of CPSs using super-resolution fluorescence microscopy. Cryo-electron microscopy analyses of the KpsMT-KpsE complex in six different states reveal a KpsE-encaged ABC transporter, rigid-body conformational rearrangements of KpsMT during ATP hydrolysis and recognition of a glycolipid inside a membrane-exposed electropositive canyon. In vivo CPS secretion assays underscore the functional importance of canyon-lining basic residues. Combined, our analyses suggest a molecular model of CPS secretion by ABC transporters.
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Affiliation(s)
- Jeremi Kuklewicz
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Jochen Zimmer
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, VA, USA.
- Howard Hughes Medical Institute, University of Virginia, Charlottesville, VA, USA.
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2
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Bowers SR, Lockhart C, Klimov DK. Binding and dimerization of PGLa peptides in anionic lipid bilayer studied by replica exchange molecular dynamics. Sci Rep 2024; 14:4972. [PMID: 38424117 PMCID: PMC10904749 DOI: 10.1038/s41598-024-55270-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Accepted: 02/21/2024] [Indexed: 03/02/2024] Open
Abstract
The 21-residue PGLa peptide is well known for antimicrobial activity attributed to its ability to compromize bacterial membranes. Using all-atom explicit solvent replica exchange molecular dynamics with solute tempering, we studied PGLa binding to a model anionic DMPC/DMPG bilayer at the high peptide:lipid ratio that promotes PGLa dimerization (a two peptides per leaflet system). As a reference we used our previous simulations at the low peptide:lipid ratio (a one peptide per leaflet system). We found that the increase in the peptide:lipid ratio suppresses PGLa helical propensity, tilts the bound peptide toward the bilayer hydrophobic core, and forces it deeper into the bilayer. Surprisingly, at the high peptide:lipid ratio PGLa binding induces weaker bilayer thinning, but deeper water permeation. We explain these effects by the cross-correlations between lipid shells surrounding PGLa that leads to a much diminished efflux of DMPC lipids from the peptide proximity at the high peptide:lipid ratio. Consistent with the experimental data the propensity for PGLa dimerization was found to be weak resulting in coexistence of monomers and dimers with distinctive properties. PGLa dimers assemble via apolar criss-cross interface and become partially expelled from the bilayer residing at the bilayer-water boundary. We rationalize their properties by the dimer tendency to preserve favorable electrostatic interactions between lysine and phosphate lipid groups as well as to avoid electrostatic repulsion between lysines in the low dielectric environment of the bilayer core. PGLa homedimer interface is predicted to be distinct from that involved in PGLa-magainin heterodimers.
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Affiliation(s)
- Steven R Bowers
- School of Systems Biology, George Mason University, Manassas, VA, 20110, USA
| | | | - Dmitri K Klimov
- School of Systems Biology, George Mason University, Manassas, VA, 20110, USA.
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3
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Pattipeiluhu R, Zeng Y, Hendrix MMRM, Voets IK, Kros A, Sharp TH. Liquid crystalline inverted lipid phases encapsulating siRNA enhance lipid nanoparticle mediated transfection. Nat Commun 2024; 15:1303. [PMID: 38347001 PMCID: PMC10861598 DOI: 10.1038/s41467-024-45666-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Accepted: 01/31/2024] [Indexed: 02/15/2024] Open
Abstract
Efficient cytosolic delivery of RNA molecules remains a formidable barrier for RNA therapeutic strategies. Lipid nanoparticles (LNPs) serve as state-of-the-art carriers that can deliver RNA molecules intracellularly, as exemplified by the recent implementation of several vaccines against SARS-CoV-2. Using a bottom-up rational design approach, we assemble LNPs that contain programmable lipid phases encapsulating small interfering RNA (siRNA). A combination of cryogenic transmission electron microscopy, cryogenic electron tomography and small-angle X-ray scattering reveals that we can form inverse hexagonal structures, which are present in a liquid crystalline nature within the LNP core. Comparison with lamellar LNPs reveals that the presence of inverse hexagonal phases enhances the intracellular silencing efficiency over lamellar structures. We then demonstrate that lamellar LNPs exhibit an in situ transition from a lamellar to inverse hexagonal phase upon interaction with anionic membranes, whereas LNPs containing pre-programmed liquid crystalline hexagonal phases bypass this transition for a more efficient one-step delivery mechanism, explaining the increased silencing effect. This rational design of LNPs with defined lipid structures aids in the understanding of the nano-bio interface and adds substantial value for LNP design, optimization and use.
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Affiliation(s)
- Roy Pattipeiluhu
- Supramolecular and Biomaterials Chemistry, Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333 CC, Leiden, The Netherlands
- Department of Cell and Chemical Biology, Leiden University Medical Center, Einthovenweg 20, 2333 ZC, Leiden, The Netherlands
- BioNTech SE, An der Goldgrube 12, 55131, Mainz, Germany
| | - Ye Zeng
- Supramolecular and Biomaterials Chemistry, Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333 CC, Leiden, The Netherlands
| | - Marco M R M Hendrix
- Self-Organizing Soft Matter, Department of Chemical Engineering and Chemistry & Institute of Complex Molecular Systems, Eindhoven University of Technology, P.O. Box 513, 5600 MB, Eindhoven, The Netherlands
| | - Ilja K Voets
- Self-Organizing Soft Matter, Department of Chemical Engineering and Chemistry & Institute of Complex Molecular Systems, Eindhoven University of Technology, P.O. Box 513, 5600 MB, Eindhoven, The Netherlands
| | - Alexander Kros
- Supramolecular and Biomaterials Chemistry, Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333 CC, Leiden, The Netherlands.
| | - Thomas H Sharp
- Department of Cell and Chemical Biology, Leiden University Medical Center, Einthovenweg 20, 2333 ZC, Leiden, The Netherlands.
- School of Biochemistry, University of Bristol, Bristol, BS8 1TD, United Kingdom.
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4
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Chaudhary R, Goodman LS, Wang S, Asimakopoulos A, Weiskirchen R, Dooley S, Ehrlich M, Henis YI. Cholesterol modulates type I/II TGF-β receptor complexes and alters the balance between Smad and Akt signaling in hepatocytes. Commun Biol 2024; 7:8. [PMID: 38168942 PMCID: PMC10761706 DOI: 10.1038/s42003-023-05654-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 11/30/2023] [Indexed: 01/05/2024] Open
Abstract
Cholesterol mediates membrane compartmentalization, affecting signaling via differential distribution of receptors and signaling mediators. While excessive cholesterol and aberrant transforming growth factor-β (TGF-β) signaling characterize multiple liver diseases, their linkage to canonical vs. non-canonical TGF-β signaling remained unclear. Here, we subjected murine hepatocytes to cholesterol depletion (CD) or enrichment (CE), followed by biophysical studies on TGF-β receptor heterocomplex formation, and output to Smad2/3 vs. Akt pathways. Prior to ligand addition, raft-dependent preformed heteromeric receptor complexes were observed. Smad2/3 phosphorylation persisted following CD or CE. CD enhanced phospho-Akt (pAkt) formation by TGF-β or epidermal growth factor (EGF) at 5 min, while reducing it at later time points. Conversely, pAkt formation by TGF-β or EGF was inhibited by CE, suggesting a direct effect on the Akt pathway. The modulation of the balance between TGF-β signaling to Smad2/3 vs. pAkt (by TGF-β or EGF) has potential implications for hepatic diseases and malignancies.
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Affiliation(s)
- Roohi Chaudhary
- Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, 6997801, Tel Aviv, Israel
- Department of Neurobiology, George S. Wise Faculty of Life Sciences, Tel Aviv University, 6997801, Tel Aviv, Israel
| | - Laureen S Goodman
- Department of Neurobiology, George S. Wise Faculty of Life Sciences, Tel Aviv University, 6997801, Tel Aviv, Israel
| | - Sai Wang
- Department of Medicine II, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, D-68167, Mannheim, Germany
| | - Anastasia Asimakopoulos
- Institute of Molecular Pathobiochemistry, Experimental Gene Therapy and Clinical Chemistry (IFMPEGKC), RWTH Aachen University Hospital, D-52074, Aachen, Germany
| | - Ralf Weiskirchen
- Institute of Molecular Pathobiochemistry, Experimental Gene Therapy and Clinical Chemistry (IFMPEGKC), RWTH Aachen University Hospital, D-52074, Aachen, Germany
| | - Steven Dooley
- Department of Medicine II, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, D-68167, Mannheim, Germany
| | - Marcelo Ehrlich
- Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, 6997801, Tel Aviv, Israel.
| | - Yoav I Henis
- Department of Neurobiology, George S. Wise Faculty of Life Sciences, Tel Aviv University, 6997801, Tel Aviv, Israel.
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5
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Sakai Y, Takahashi S, Koyama-Honda I, Saito C, Mizushima N. Experimental determination and mathematical modeling of standard shapes of forming autophagosomes. Nat Commun 2024; 15:91. [PMID: 38167876 PMCID: PMC10762205 DOI: 10.1038/s41467-023-44442-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Accepted: 12/12/2023] [Indexed: 01/05/2024] Open
Abstract
The formation of autophagosomes involves dynamic morphological changes of a phagophore from a flat membrane cisterna into a cup-shaped intermediate and a spherical autophagosome. However, the physical mechanism behind these morphological changes remains elusive. Here, we determine the average shapes of phagophores by statistically investigating three-dimensional electron micrographs of more than 100 phagophores. The results show that the cup-shaped structures adopt a characteristic morphology; they are longitudinally elongated, and the rim is catenoidal with an outwardly recurved shape. To understand these characteristic shapes, we establish a theoretical model of the shape of entire phagophores. The model quantitatively reproduces the average morphology and reveals that the characteristic shape of phagophores is primarily determined by the relative size of the open rim to the total surface area. These results suggest that the seemingly complex morphological changes during autophagosome formation follow a stable path determined by elastic bending energy minimization.
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Affiliation(s)
- Yuji Sakai
- Department of Biochemistry and Molecular Biology, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, 113-0033, Japan.
- Department of Biosystems Science, Institute for Life and Medical Sciences, Kyoto University, Sakyo-ku, Kyoto, 606-8507, Japan.
- Interdisciplinary Theoretical and Mathematical Sciences (iTHEMS) Program, RIKEN, Wako, Saitama, 351-0198, Japan.
| | - Satoru Takahashi
- Department of Biochemistry and Molecular Biology, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, 113-0033, Japan
- Department of Neurosurgery, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, 113-8510, Japan
| | - Ikuko Koyama-Honda
- Department of Biochemistry and Molecular Biology, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Chieko Saito
- Department of Biochemistry and Molecular Biology, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Noboru Mizushima
- Department of Biochemistry and Molecular Biology, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, 113-0033, Japan.
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6
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Sadhu RK, Hernandez-Padilla C, Eisenbach YE, Penič S, Zhang L, Vishwasrao HD, Behkam B, Konstantopoulos K, Shroff H, Iglič A, Peles E, Nain AS, Gov NS. Author Correction: Experimental and theoretical model for the origin of coiling of cellular protrusions around fibers. Nat Commun 2023; 14:8518. [PMID: 38129398 PMCID: PMC10739969 DOI: 10.1038/s41467-023-44423-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2023] Open
Affiliation(s)
- Raj Kumar Sadhu
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, 7610001, Israel.
- Institut Curie, PSL Research University, CNRS, UMR 168, Paris, France.
| | | | - Yael Eshed Eisenbach
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Samo Penič
- Laboratory of Physics, Faculty of Electrical Engineering, University of Ljubljana, Ljubljana, Slovenia
| | - Lixia Zhang
- Advanced Imaging and Microscopy Resource, National Institutes of Health, Bethesda, MD, USA
| | - Harshad D Vishwasrao
- Advanced Imaging and Microscopy Resource, National Institutes of Health, Bethesda, MD, USA
| | - Bahareh Behkam
- Department of Mechanical Engineering, Virginia Tech, Blacksburg, VA, 24061, USA
| | | | - Hari Shroff
- Advanced Imaging and Microscopy Resource, National Institutes of Health, Bethesda, MD, USA
- Laboratory of High Resolution Optical Imaging, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD, USA
| | - Aleš Iglič
- Laboratory of Physics, Faculty of Electrical Engineering, University of Ljubljana, Ljubljana, Slovenia
| | - Elior Peles
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Amrinder S Nain
- Department of Mechanical Engineering, Virginia Tech, Blacksburg, VA, 24061, USA.
| | - Nir S Gov
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, 7610001, Israel.
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7
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He Y, Yang S, Liu P, Li K, Jin K, Becker R, Zhang J, Lin C, Xia J, Ma Z, Ma Z, Zhong R, Lee LP, Huang TJ. Acoustofluidic Interfaces for the Mechanobiological Secretome of MSCs. Nat Commun 2023; 14:7639. [PMID: 37993431 PMCID: PMC10665559 DOI: 10.1038/s41467-023-43239-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Accepted: 11/03/2023] [Indexed: 11/24/2023] Open
Abstract
While mesenchymal stem cells (MSCs) have gained enormous attention due to their unique properties of self-renewal, colony formation, and differentiation potential, the MSC secretome has become attractive due to its roles in immunomodulation, anti-inflammatory activity, angiogenesis, and anti-apoptosis. However, the precise stimulation and efficient production of the MSC secretome for therapeutic applications are challenging problems to solve. Here, we report on Acoustofluidic Interfaces for the Mechanobiological Secretome of MSCs: AIMS. We create an acoustofluidic mechanobiological environment to form reproducible three-dimensional MSC aggregates, which produce the MSC secretome with high efficiency. We confirm the increased MSC secretome is due to improved cell-cell interactions using AIMS: the key mediator N-cadherin was up-regulated while functional blocking of N-cadherin resulted in no enhancement of the secretome. After being primed by IFN-γ, the secretome profile of the MSC aggregates contains more anti-inflammatory cytokines and can be used to inhibit the pro-inflammatory response of M1 phenotype macrophages, suppress T cell activation, and support B cell functions. As such, the MSC secretome can be modified for personalized secretome-based therapies. AIMS acts as a powerful tool for improving the MSC secretome and precisely tuning the secretory profile to develop new treatments in translational medicine.
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Affiliation(s)
- Ye He
- Thomas Lord Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC, 27708, USA
| | - Shujie Yang
- Thomas Lord Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC, 27708, USA
| | - Pengzhan Liu
- Thomas Lord Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC, 27708, USA
| | - Ke Li
- Thomas Lord Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC, 27708, USA
| | - Ke Jin
- Thomas Lord Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC, 27708, USA
| | - Ryan Becker
- Department of Biomedical Engineering, Duke University, Durham, NC, 27708, USA
| | - Jinxin Zhang
- Thomas Lord Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC, 27708, USA
| | - Chuanchuan Lin
- Department of Blood Transfusion, Irradiation Biology Laboratory, Xinqiao Hospital, Chongqing, 400037, China
| | - Jianping Xia
- Thomas Lord Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC, 27708, USA
| | - Zhehan Ma
- Department of Biomedical Engineering, Duke University, Durham, NC, 27708, USA
| | - Zhiteng Ma
- Thomas Lord Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC, 27708, USA
| | - Ruoyu Zhong
- Thomas Lord Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC, 27708, USA
| | - Luke P Lee
- Harvard Medical School, Harvard University, Renal Division and Division of Engineering in Medicine, Department of Medicine, Brigham and Women's Hospital, Boston, MA, 02115, USA.
- Department of Bioengineering, University of California, Berkeley, Berkeley, CA, 94720, USA.
- Department of Electrical Engineering and Computer Science, University of California, Berkeley, Berkeley, CA, 94720, USA.
- Department of Biophysics, Institute of Quantum Biophysics, Sungkyunkwan University, Suwon, Korea.
- Department of Chemistry and Nanoscience, Ewha Womans University, Seoul, Korea.
| | - Tony Jun Huang
- Thomas Lord Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC, 27708, USA.
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8
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Dieudonné T, Kümmerer F, Laursen MJ, Stock C, Flygaard RK, Khalid S, Lenoir G, Lyons JA, Lindorff-Larsen K, Nissen P. Activation and substrate specificity of the human P4-ATPase ATP8B1. Nat Commun 2023; 14:7492. [PMID: 37980352 PMCID: PMC10657443 DOI: 10.1038/s41467-023-42828-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Accepted: 10/23/2023] [Indexed: 11/20/2023] Open
Abstract
Asymmetric distribution of phospholipids in eukaryotic membranes is essential for cell integrity, signaling pathways, and vesicular trafficking. P4-ATPases, also known as flippases, participate in creating and maintaining this asymmetry through active transport of phospholipids from the exoplasmic to the cytosolic leaflet. Here, we present a total of nine cryo-electron microscopy structures of the human flippase ATP8B1-CDC50A complex at 2.4 to 3.1 Å overall resolution, along with functional and computational studies, addressing the autophosphorylation steps from ATP, substrate recognition and occlusion, as well as a phosphoinositide binding site. We find that the P4-ATPase transport site is occupied by water upon phosphorylation from ATP. Additionally, we identify two different autoinhibited states, a closed and an outward-open conformation. Furthermore, we identify and characterize the PI(3,4,5)P3 binding site of ATP8B1 in an electropositive pocket between transmembrane segments 5, 7, 8, and 10. Our study also highlights the structural basis of a broad lipid specificity of ATP8B1 and adds phosphatidylinositol as a transport substrate for ATP8B1. We report a critical role of the sn-2 ester bond of glycerophospholipids in substrate recognition by ATP8B1 through conserved S403. These findings provide fundamental insights into ATP8B1 catalytic cycle and regulation, and substrate recognition in P4-ATPases.
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Affiliation(s)
- Thibaud Dieudonné
- DANDRITE, Nordic EMBL Partnership for Molecular Medicine, Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark.
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France.
| | - Felix Kümmerer
- Structural Biology and NMR Laboratory & Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Michelle Juknaviciute Laursen
- DANDRITE, Nordic EMBL Partnership for Molecular Medicine, Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Charlott Stock
- DANDRITE, Nordic EMBL Partnership for Molecular Medicine, Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Rasmus Kock Flygaard
- DANDRITE, Nordic EMBL Partnership for Molecular Medicine, Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Syma Khalid
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Guillaume Lenoir
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
| | - Joseph A Lyons
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
- Interdisciplinary Nanoscience Centre (iNANO) Aarhus University, Aarhus, Denmark
| | - Kresten Lindorff-Larsen
- Structural Biology and NMR Laboratory & Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Poul Nissen
- DANDRITE, Nordic EMBL Partnership for Molecular Medicine, Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark.
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9
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Feng X, Sun D, Li Y, Zhang J, Liu S, Zhang D, Zheng J, Xi Q, Liang H, Zhao W, Li Y, Xu M, He J, Liu T, Hasim A, Ma M, Xu P, Mi N. Local membrane source gathering by p62 body drives autophagosome formation. Nat Commun 2023; 14:7338. [PMID: 37957156 PMCID: PMC10643672 DOI: 10.1038/s41467-023-42829-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 10/23/2023] [Indexed: 11/15/2023] Open
Abstract
Autophagosomes are double-membrane vesicles generated intracellularly to encapsulate substrates for lysosomal degradation during autophagy. Phase separated p62 body plays pivotal roles during autophagosome formation, however, the underlying mechanisms are still not fully understood. Here we describe a spatial membrane gathering mode by which p62 body functions in autophagosome formation. Mass spectrometry-based proteomics reveals significant enrichment of vesicle trafficking components within p62 body. Combining cellular experiments and biochemical reconstitution assays, we confirm the gathering of ATG9 and ATG16L1-positive vesicles around p62 body, especially in Atg2ab DKO cells with blocked lipid transfer and vesicle fusion. Interestingly, p62 body also regulates ATG9 and ATG16L vesicle trafficking flux intracellularly. We further determine the lipid contents associated with p62 body via lipidomic profiling. Moreover, with in vitro kinase assay, we uncover the functions of p62 body as a platform to assemble ULK1 complex and invigorate PI3KC3-C1 kinase cascade for PI3P generation. Collectively, our study raises a membrane-based working model for multifaceted p62 body in controlling autophagosome biogenesis, and highlights the interplay between membraneless condensates and membrane vesicles in regulating cellular functions.
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Affiliation(s)
- Xuezhao Feng
- State Key Laboratory of Pathogenesis, Prevention and Treatment of Central Asian High Incidence Diseases, Clinical Medical Research Institute, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, 830011, Xinjiang, China
- Basic Medical College, Xinjiang Medical University, Urumqi, 830011, Xinjiang, China
| | - Daxiao Sun
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307, Dresden, Germany.
| | - Yanchang Li
- State Key Laboratory of Proteomics, National Center for Protein Sciences (Beijing), Research Unit of Proteomics & Research and Development of New Drug of Chinese Academy of Medical Sciences, Beijing Proteome Research Center, Institute of Lifeomics, 102206, Beijing, China
| | - Jinpei Zhang
- State Key Laboratory of Pathogenesis, Prevention and Treatment of Central Asian High Incidence Diseases, Clinical Medical Research Institute, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, 830011, Xinjiang, China
- Basic Medical College, Xinjiang Medical University, Urumqi, 830011, Xinjiang, China
| | - Shiyu Liu
- State Key Laboratory of Pathogenesis, Prevention and Treatment of Central Asian High Incidence Diseases, Clinical Medical Research Institute, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, 830011, Xinjiang, China
- Basic Medical College, Xinjiang Medical University, Urumqi, 830011, Xinjiang, China
| | - Dachuan Zhang
- School of Life Sciences, Tsinghua University, 100084, Beijing, China
| | - Jingxiang Zheng
- School of Life Sciences, Tsinghua University, 100084, Beijing, China
| | - Qing Xi
- State Key Laboratory of Pathogenesis, Prevention and Treatment of Central Asian High Incidence Diseases, Clinical Medical Research Institute, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, 830011, Xinjiang, China
- Basic Medical College, Xinjiang Medical University, Urumqi, 830011, Xinjiang, China
| | - Haisha Liang
- School of Life Sciences, Tsinghua University, 100084, Beijing, China
| | - Wenkang Zhao
- School of Life Sciences, Tsinghua University, 100084, Beijing, China
| | - Ying Li
- School of Life Sciences, Tsinghua University, 100084, Beijing, China
| | - Mengbo Xu
- State Key Laboratory of Pathogenesis, Prevention and Treatment of Central Asian High Incidence Diseases, Clinical Medical Research Institute, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, 830011, Xinjiang, China
- Basic Medical College, Xinjiang Medical University, Urumqi, 830011, Xinjiang, China
| | - Jiayu He
- State Key Laboratory of Pathogenesis, Prevention and Treatment of Central Asian High Incidence Diseases, Clinical Medical Research Institute, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, 830011, Xinjiang, China
- Basic Medical College, Xinjiang Medical University, Urumqi, 830011, Xinjiang, China
| | - Tong Liu
- State Key Laboratory of Pathogenesis, Prevention and Treatment of Central Asian High Incidence Diseases, Clinical Medical Research Institute, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, 830011, Xinjiang, China
- Basic Medical College, Xinjiang Medical University, Urumqi, 830011, Xinjiang, China
| | - Ayshamgul Hasim
- Basic Medical College, Xinjiang Medical University, Urumqi, 830011, Xinjiang, China
- Department of Pathology, School of Basic Medicine, Xinjiang Medical University, Urumqi, 830011, Xinjiang, China
| | - Meisheng Ma
- Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Ping Xu
- State Key Laboratory of Proteomics, National Center for Protein Sciences (Beijing), Research Unit of Proteomics & Research and Development of New Drug of Chinese Academy of Medical Sciences, Beijing Proteome Research Center, Institute of Lifeomics, 102206, Beijing, China.
| | - Na Mi
- State Key Laboratory of Pathogenesis, Prevention and Treatment of Central Asian High Incidence Diseases, Clinical Medical Research Institute, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, 830011, Xinjiang, China.
- Basic Medical College, Xinjiang Medical University, Urumqi, 830011, Xinjiang, China.
- Key Laboratory of High Incidence Disease Research in Xinjiang (Xinjiang Medical University), Ministry of Education, Urumqi, 830011, Xinjiang, China.
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10
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Lai LTF, Balaraman J, Zhou F, Matthies D. Cryo-EM structures of human magnesium channel MRS2 reveal gating and regulatory mechanisms. Nat Commun 2023; 14:7207. [PMID: 37938562 PMCID: PMC10632456 DOI: 10.1038/s41467-023-42599-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Accepted: 10/16/2023] [Indexed: 11/09/2023] Open
Abstract
Magnesium ions (Mg2+) play an essential role in cellular physiology. In mitochondria, protein and ATP synthesis and various metabolic pathways are directly regulated by Mg2+. MRS2, a magnesium channel located in the inner mitochondrial membrane, mediates the influx of Mg2+ into the mitochondrial matrix and regulates Mg2+ homeostasis. Knockdown of MRS2 in human cells leads to reduced uptake of Mg2+ into mitochondria and disruption of the mitochondrial metabolism. Despite the importance of MRS2, the Mg2+ translocation and regulation mechanisms of MRS2 are still unclear. Here, using cryo-EM we report the structures of human MRS2 in the presence and absence of Mg2+ at 2.8 Å and 3.3 Å, respectively. From the homo-pentameric structures, we identify R332 and M336 as major gating residues, which are then tested using mutagenesis and two cellular divalent ion uptake assays. A network of hydrogen bonds is found connecting the gating residue R332 to the soluble domain, potentially regulating the gate. Two Mg2+-binding sites are identified in the MRS2 soluble domain, distinct from the two sites previously reported in CorA, a homolog of MRS2 in prokaryotes. Altogether, this study provides the molecular basis for understanding the Mg2+ translocation and regulatory mechanisms of MRS2.
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Affiliation(s)
- Louis Tung Faat Lai
- Unit on Structural Biology, Division of Basic and Translational Biophysics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Jayashree Balaraman
- Unit on Structural Biology, Division of Basic and Translational Biophysics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Fei Zhou
- Unit on Structural Biology, Division of Basic and Translational Biophysics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Doreen Matthies
- Unit on Structural Biology, Division of Basic and Translational Biophysics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, 20892, USA.
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11
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Drabik D, Drab M, Penič S, Iglič A, Czogalla A. Investigation of nano- and microdomains formed by ceramide 1 phosphate in lipid bilayers. Sci Rep 2023; 13:18570. [PMID: 37903839 PMCID: PMC10616280 DOI: 10.1038/s41598-023-45575-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Accepted: 10/21/2023] [Indexed: 11/01/2023] Open
Abstract
Biological membranes are renowned for their intricate complexity, with the formation of membrane domains being pivotal to the successful execution of numerous cellular processes. However, due to their nanoscale characteristics, these domains are often understudied, as the experimental techniques required for quantitative investigation present significant challenges. In this study we employ spot-variation z-scan fluorescence correlation spectroscopy (svzFCS) tailored for artificial lipid vesicles of varying composition and combine this approach with high-resolution imaging. This method has been harnessed to examine the lipid-segregation behavior of distinct types of ceramide-1-phosphate (C1P), a crucial class of signaling molecules, within these membranes. Moreover, we provide a quantitative portrayal of the lipid membranes studied and the domains induced by C1P at both nano and microscales. Given the lack of definitive conclusions from the experimental data obtained, it was supplemented with comprehensive in silico studies-including the analysis of diffusion coefficient via molecular dynamics and domain populations via Monte Carlo simulations. This approach enhanced our insight into the dynamic behavior of these molecules within model lipid membranes, confirming that nano- and microdomains can co-exist in lipid vesicles.
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Affiliation(s)
- Dominik Drabik
- Laboratory of Cytobiochemistry, Faculty of Biotechnology, University of Wroclaw, F. Joliot-Curie 14a, 50-383, Wrocław, Poland.
- Department of Biomedical Engineering, Faculty of Fundamental Problems of Technology, Pl. Grunwaldzki 13, 50-377, Wrocław, Poland.
| | - Mitja Drab
- Laboratory of Physics, Faculty of Electrical Engineering, University of Ljubljana, Tržaška cesta 25, 1000, Ljubljana, Slovenia.
| | - Samo Penič
- Laboratory of Physics, Faculty of Electrical Engineering, University of Ljubljana, Tržaška cesta 25, 1000, Ljubljana, Slovenia
- Laboratory of Bioelectromagnetics, Faculty of Electrical Engineering, University of Ljubljana, Tržaška cesta 25, 1000, Ljubljana, Slovenia
| | - Aleš Iglič
- Laboratory of Physics, Faculty of Electrical Engineering, University of Ljubljana, Tržaška cesta 25, 1000, Ljubljana, Slovenia
| | - Aleksander Czogalla
- Laboratory of Cytobiochemistry, Faculty of Biotechnology, University of Wroclaw, F. Joliot-Curie 14a, 50-383, Wrocław, Poland.
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12
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Handlin LJ, Dai G. Direct regulation of the voltage sensor of HCN channels by membrane lipid compartmentalization. Nat Commun 2023; 14:6595. [PMID: 37852983 PMCID: PMC10584925 DOI: 10.1038/s41467-023-42363-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Accepted: 10/09/2023] [Indexed: 10/20/2023] Open
Abstract
Ion channels function within a membrane environment characterized by dynamic lipid compartmentalization. Limited knowledge exists regarding the response of voltage-gated ion channels to transmembrane potential within distinct membrane compartments. By leveraging fluorescence lifetime imaging microscopy (FLIM) and Förster resonance energy transfer (FRET), we visualized the localization of hyperpolarization-activated cyclic nucleotide-gated (HCN) channels in membrane domains. HCN4 exhibits a greater propensity for incorporation into ordered lipid domains compared to HCN1. To investigate the conformational changes of the S4 helix voltage sensor of HCN channels, we used dual stop-codon suppression to incorporate different noncanonical amino acids, orthogonal click chemistry for site-specific fluorescence labeling, and transition metal FLIM-FRET. Remarkably, altered FRET levels were observed between VSD sites within HCN channels upon disruption of membrane domains. We propose that the voltage-sensor rearrangements, directly influenced by membrane lipid domains, can explain the heightened activity of pacemaker HCN channels when localized in cholesterol-poor, disordered lipid domains, leading to membrane hyperexcitability and diseases.
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Affiliation(s)
- Lucas J Handlin
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, 1100 South Grand Blvd., St. Louis, MO, 63104, USA
| | - Gucan Dai
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, 1100 South Grand Blvd., St. Louis, MO, 63104, USA.
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13
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Mangiarotti A, Siri M, Tam NW, Zhao Z, Malacrida L, Dimova R. Biomolecular condensates modulate membrane lipid packing and hydration. Nat Commun 2023; 14:6081. [PMID: 37770422 PMCID: PMC10539446 DOI: 10.1038/s41467-023-41709-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Accepted: 09/15/2023] [Indexed: 09/30/2023] Open
Abstract
Membrane wetting by biomolecular condensates recently emerged as a key phenomenon in cell biology, playing an important role in a diverse range of processes across different organisms. However, an understanding of the molecular mechanisms behind condensate formation and interaction with lipid membranes is still missing. To study this, we exploited the properties of the dyes ACDAN and LAURDAN as nano-environmental sensors in combination with phasor analysis of hyperspectral and lifetime imaging microscopy. Using glycinin as a model condensate-forming protein and giant vesicles as model membranes, we obtained vital information on the process of condensate formation and membrane wetting. Our results reveal that glycinin condensates display differences in water dynamics when changing the salinity of the medium as a consequence of rearrangements in the secondary structure of the protein. Remarkably, analysis of membrane-condensates interaction with protein as well as polymer condensates indicated a correlation between increased wetting affinity and enhanced lipid packing. This is demonstrated by a decrease in the dipolar relaxation of water across all membrane-condensate systems, suggesting a general mechanism to tune membrane packing by condensate wetting.
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Affiliation(s)
- Agustín Mangiarotti
- Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14476, Potsdam, Germany.
| | - Macarena Siri
- Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14476, Potsdam, Germany
| | - Nicky W Tam
- Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14476, Potsdam, Germany
| | - Ziliang Zhao
- Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14476, Potsdam, Germany
- Leibniz Institute of Photonic Technology e.V., Albert-Einstein-Straße 9, 07745, Jena, Germany
- Institute of Applied Optics and Biophysics, Friedrich-Schiller-University Jena, Max-Wien Platz 1, 07743, Jena, Germany
| | - Leonel Malacrida
- Departamento de Fisiopatología, Hospital de Clínicas, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay.
- Advanced Bioimaging Unit, Institut Pasteur of Montevideo and Universidad de la República, Montevideo, Uruguay.
| | - Rumiana Dimova
- Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14476, Potsdam, Germany.
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14
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Mikheyeva IV, Sun J, Huang KC, Silhavy TJ. Mechanism of outer membrane destabilization by global reduction of protein content. Nat Commun 2023; 14:5715. [PMID: 37714857 PMCID: PMC10504340 DOI: 10.1038/s41467-023-40396-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 07/26/2023] [Indexed: 09/17/2023] Open
Abstract
The outer membrane (OM) of Gram-negative bacteria such as Escherichia coli is an asymmetric bilayer with the glycolipid lipopolysaccharide (LPS) in the outer leaflet and glycerophospholipids in the inner. Nearly all integral OM proteins (OMPs) have a characteristic β-barrel fold and are assembled in the OM by the BAM complex, which contains one essential β-barrel protein (BamA), one essential lipoprotein (BamD), and three non-essential lipoproteins (BamBCE). A gain-of-function mutation in bamA enables survival in the absence of BamD, showing that the essential function of this protein is regulatory. Here, we demonstrate that the global reduction in OMPs caused by BamD loss weakens the OM, altering cell shape and causing OM rupture in spent medium. To fill the void created by OMP loss, phospholipids (PLs) flip into the outer leaflet. Under these conditions, mechanisms that remove PLs from the outer leaflet create tension between the OM leaflets, which contributes to membrane rupture. Rupture is prevented by suppressor mutations that release the tension by halting PL removal from the outer leaflet. However, these suppressors do not restore OM stiffness or normal cell shape, revealing a possible connection between OM stiffness and cell shape.
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Affiliation(s)
- Irina V Mikheyeva
- Department of Molecular Biology, Princeton University, Princeton, NJ, 08540, USA
| | - Jiawei Sun
- Department of Bioengineering, Stanford University, Stanford, CA, 94305, USA
| | - Kerwyn Casey Huang
- Department of Bioengineering, Stanford University, Stanford, CA, 94305, USA.
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, 94305, USA.
- Chan Zuckerberg Biohub, San Francisco, CA, 94158, USA.
| | - Thomas J Silhavy
- Department of Molecular Biology, Princeton University, Princeton, NJ, 08540, USA.
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15
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Sadhu RK, Hernandez-Padilla C, Eisenbach YE, Penič S, Zhang L, Vishwasrao HD, Behkam B, Konstantopoulos K, Shroff H, Iglič A, Peles E, Nain AS, Gov NS. Experimental and theoretical model for the origin of coiling of cellular protrusions around fibers. Nat Commun 2023; 14:5612. [PMID: 37699891 PMCID: PMC10497540 DOI: 10.1038/s41467-023-41273-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 08/29/2023] [Indexed: 09/14/2023] Open
Abstract
Protrusions at the leading-edge of a cell play an important role in sensing the extracellular cues during cellular spreading and motility. Recent studies provided indications that these protrusions wrap (coil) around the extracellular fibers. However, the physics of this coiling process, and the mechanisms that drive it, are not well understood. We present a combined theoretical and experimental study of the coiling of cellular protrusions on fibers of different geometry. Our theoretical model describes membrane protrusions that are produced by curved membrane proteins that recruit the protrusive forces of actin polymerization, and identifies the role of bending and adhesion energies in orienting the leading-edges of the protrusions along the azimuthal (coiling) direction. Our model predicts that the cell's leading-edge coils on fibers with circular cross-section (above some critical radius), but the coiling ceases for flattened fibers of highly elliptical cross-section. These predictions are verified by 3D visualization and quantitation of coiling on suspended fibers using Dual-View light-sheet microscopy (diSPIM). Overall, we provide a theoretical framework, supported by experiments, which explains the physical origin of the coiling phenomenon.
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Affiliation(s)
- Raj Kumar Sadhu
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, 7610001, Israel.
- Institut Curie, PSL Research University, CNRS, UMR 168, Paris, France.
| | | | - Yael Eshed Eisenbach
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Samo Penič
- Laboratory of Physics, Faculty of Electrical Engineering, University of Ljubljana, Ljubljana, Slovenia
| | - Lixia Zhang
- Advanced Imaging and Microscopy Resource, National Institutes of Health, Bethesda, MD, USA
| | - Harshad D Vishwasrao
- Advanced Imaging and Microscopy Resource, National Institutes of Health, Bethesda, MD, USA
| | - Bahareh Behkam
- Department of Mechanical Engineering, Virginia Tech, Blacksburg, VA, 24061, USA
| | | | - Hari Shroff
- Advanced Imaging and Microscopy Resource, National Institutes of Health, Bethesda, MD, USA
- Laboratory of High Resolution Optical Imaging, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD, USA
| | - Aleš Iglič
- Laboratory of Physics, Faculty of Electrical Engineering, University of Ljubljana, Ljubljana, Slovenia
| | - Elior Peles
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Amrinder S Nain
- Department of Mechanical Engineering, Virginia Tech, Blacksburg, VA, 24061, USA.
| | - Nir S Gov
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, 7610001, Israel.
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16
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Liu S, Sommese RF, Nedoma NL, Stevens LM, Dutra JK, Zhang L, Edmonds DJ, Wang Y, Garnsey M, Clasquin MF. Structural basis of lipid-droplet localization of 17-beta-hydroxysteroid dehydrogenase 13. Nat Commun 2023; 14:5158. [PMID: 37620305 PMCID: PMC10449848 DOI: 10.1038/s41467-023-40766-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Accepted: 08/07/2023] [Indexed: 08/26/2023] Open
Abstract
Hydroxysteroid 17-beta-dehydrogenase 13 (HSD17B13) is a hepatic lipid droplet-associated enzyme that is upregulated in patients with non-alcoholic fatty liver disease. Recently, there have been several reports that predicted loss of function variants in HSD17B13 protect against the progression of steatosis to non-alcoholic steatohepatitis with fibrosis and hepatocellular carcinoma. Here we report crystal structures of full length HSD17B13 in complex with its NAD+ cofactor, and with lipid/detergent molecules and small molecule inhibitors from two distinct series in the ligand binding pocket. These structures provide insights into a mechanism for lipid droplet-associated proteins anchoring to membranes as well as a basis for HSD17B13 variants disrupting function. Two series of inhibitors interact with the active site residues and the bound cofactor similarly, yet they occupy different paths leading to the active site. These structures provide ideas for structure-based design of inhibitors that may be used in the treatment of liver disease.
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Affiliation(s)
- Shenping Liu
- Medicine Design, Pfizer Inc, Groton, CT, 06340, USA.
| | | | | | | | - Jason K Dutra
- Medicine Design, Pfizer Inc, Cambridge, MA, 02139, USA
| | - Liying Zhang
- Medicine Design, Pfizer Inc, Cambridge, MA, 02139, USA
- Discovery Chemistry, Merck Research Laboratories, Cambridge, MA, USA
| | - David J Edmonds
- Medicine Design, Pfizer Inc, Cambridge, MA, 02139, USA
- Medicinal Chemistry, Roche, Basel, Switzerland
| | - Yang Wang
- Medicine Design, Pfizer Inc, Cambridge, MA, 02139, USA
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17
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Benn G, Silhavy TJ, Kleanthous C, Hoogenboom BW. Antibiotics and hexagonal order in the bacterial outer membrane. Nat Commun 2023; 14:4772. [PMID: 37558670 PMCID: PMC10412626 DOI: 10.1038/s41467-023-40275-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Accepted: 07/20/2023] [Indexed: 08/11/2023] Open
Affiliation(s)
- Georgina Benn
- Department of Molecular Biology, Princeton University, Princeton, NJ, 08544, USA
| | - Thomas J Silhavy
- Department of Molecular Biology, Princeton University, Princeton, NJ, 08544, USA
| | - Colin Kleanthous
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK
| | - Bart W Hoogenboom
- London Centre for Nanotechnology, University College London, London, WC1H 0AH, UK.
- Department of Physics and Astronomy, University College London, London, WC1E 6BT, UK.
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18
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Nguyen C, Lei HT, Lai LTF, Gallenito MJ, Mu X, Matthies D, Gonen T. Lipid flipping in the omega-3 fatty-acid transporter. Nat Commun 2023; 14:2571. [PMID: 37156797 PMCID: PMC10167227 DOI: 10.1038/s41467-023-37702-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 03/28/2023] [Indexed: 05/10/2023] Open
Abstract
Mfsd2a is the transporter for docosahexaenoic acid (DHA), an omega-3 fatty acid, across the blood brain barrier (BBB). Defects in Mfsd2a are linked to ailments from behavioral and motor dysfunctions to microcephaly. Mfsd2a transports long-chain unsaturated fatty-acids, including DHA and α-linolenic acid (ALA), that are attached to the zwitterionic lysophosphatidylcholine (LPC) headgroup. Even with the recently determined structures of Mfsd2a, the molecular details of how this transporter performs the energetically unfavorable task of translocating and flipping lysolipids across the lipid bilayer remains unclear. Here, we report five single-particle cryo-EM structures of Danio rerio Mfsd2a (drMfsd2a): in the inward-open conformation in the ligand-free state and displaying lipid-like densities modeled as ALA-LPC at four distinct positions. These Mfsd2a snapshots detail the flipping mechanism for lipid-LPC from outer to inner membrane leaflet and release for membrane integration on the cytoplasmic side. These results also map Mfsd2a mutants that disrupt lipid-LPC transport and are associated with disease.
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Affiliation(s)
- Chi Nguyen
- Howard Hughes Medical Institute, University of California Los Angeles, Los Angeles, CA, 90095, USA
- Department of Biological Chemistry, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Hsiang-Ting Lei
- Howard Hughes Medical Institute, University of California Los Angeles, Los Angeles, CA, 90095, USA
- Janelia Research Campus, Howard Hughes Medical Institute, 19700 Helix Drive, Ashburn, VA, 20147, USA
| | - Louis Tung Faat Lai
- Unit on Structural Biology, Division of Basic and Translational Biophysics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Marc J Gallenito
- Howard Hughes Medical Institute, University of California Los Angeles, Los Angeles, CA, 90095, USA
- Department of Biological Chemistry, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Xuelang Mu
- Howard Hughes Medical Institute, University of California Los Angeles, Los Angeles, CA, 90095, USA
- Department of Biological Chemistry, University of California Los Angeles, Los Angeles, CA, 90095, USA
- Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Doreen Matthies
- Janelia Research Campus, Howard Hughes Medical Institute, 19700 Helix Drive, Ashburn, VA, 20147, USA.
- Unit on Structural Biology, Division of Basic and Translational Biophysics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, 20892, USA.
| | - Tamir Gonen
- Howard Hughes Medical Institute, University of California Los Angeles, Los Angeles, CA, 90095, USA.
- Department of Biological Chemistry, University of California Los Angeles, Los Angeles, CA, 90095, USA.
- Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA, 90095, USA.
- Departments of Physiology, University of California Los Angeles, Los Angeles, CA, 90095, USA.
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19
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Choi S, Kang B, Yang E, Kim K, Kwak MK, Chang PS, Jung HS. Precise control of liposome size using characteristic time depends on solvent type and membrane properties. Sci Rep 2023; 13:4728. [PMID: 36959258 PMCID: PMC10036480 DOI: 10.1038/s41598-023-31895-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Accepted: 03/20/2023] [Indexed: 03/25/2023] Open
Abstract
Controlling the sizes of liposomes is critical in drug delivery systems because it directly influences their cellular uptake, transportation, and accumulation behavior. Although hydrodynamic focusing has frequently been employed when synthesizing nano-sized liposomes, little is known regarding how flow characteristics determine liposome formation. Here, various sizes of homogeneous liposomes (50-400 nm) were prepared according to flow rate ratios in two solvents, ethanol, and isopropyl alcohol (IPA). Relatively small liposomes formed in ethanol due to its low viscosity and high diffusivity, whereas larger, more poly-dispersed liposomes formed when using IPA as a solvent. This difference was investigated via numerical simulations using the characteristic time factor to predict the liposome size; this approach was also used to examine the flow characteristics inside the microfluidic channel. In case of the liposomes, the membrane rigidity also has a critical role in determining their size. The increased viscosity and packing density of the membrane by addition of cholesterol confirmed by fluorescence anisotropy and polarity lead to increase in liposome size (40-530 nm). However, the interposition of short-chain lipids de-aligned the bilayer membrane, leading to its degradation; this decreased the liposome size. Adding short-chain lipids linearly decreased the liposome size (130-230 nm), but at a shallower gradient than that of cholesterol. This analytical study expands the understanding of microfluidic environment in the liposome synthesis by offering design parameters and their relation to the size of liposomes.
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Affiliation(s)
- Sunghak Choi
- Center for Food and Bioconvergence, Department of Food Science and Biotechnology, Seoul National University, Seoul, 08826, South Korea
| | - Bongsu Kang
- Center for Food and Bioconvergence, Department of Food Science and Biotechnology, Seoul National University, Seoul, 08826, South Korea
- School of Mechanical Engineering, Kyungpook National University, Daegu, 41566, South Korea
| | - Eunhye Yang
- Department of Agricultural Biotechnology, Seoul National University, Seoul, 08826, Republic of Korea
| | - Keesung Kim
- Research Inst. of Advanced. Materials, Collage of Engineering, Seoul National University, Seoul, 08826, South Korea
| | - Moon Kyu Kwak
- School of Mechanical Engineering, Kyungpook National University, Daegu, 41566, South Korea.
| | - Pahn-Shick Chang
- Center for Food and Bioconvergence, Department of Food Science and Biotechnology, Seoul National University, Seoul, 08826, South Korea.
- Department of Agricultural Biotechnology, Seoul National University, Seoul, 08826, Republic of Korea.
- Center for Agricultural Microorganism and Enzyme, Seoul National University, Seoul, 08826, Republic of Korea.
- Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, 08826, Republic of Korea.
| | - Ho-Sup Jung
- Center for Food and Bioconvergence, Department of Food Science and Biotechnology, Seoul National University, Seoul, 08826, South Korea.
- Nbiocell Inc, Siheung SNU Start-up Campus, Gyeonggi-do, 15011, Republic of Korea.
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20
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Dumesnil C, Vanharanta L, Prasanna X, Omrane M, Carpentier M, Bhapkar A, Enkavi G, Salo VT, Vattulainen I, Ikonen E, Thiam AR. Cholesterol esters form supercooled lipid droplets whose nucleation is facilitated by triacylglycerols. Nat Commun 2023; 14:915. [PMID: 36807572 DOI: 10.1038/s41467-023-36375-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 01/27/2023] [Indexed: 02/19/2023] Open
Abstract
Cellular cholesterol can be metabolized to its fatty acid esters, cholesteryl esters (CEs), to be stored in lipid droplets (LDs). With triacylglycerols (TGs), CEs represent the main neutral lipids in LDs. However, while TG melts at ~4 °C, CE melts at ~44 °C, raising the question of how CE-rich LDs form in cells. Here, we show that CE forms supercooled droplets when the CE concentration in LDs is above 20% to TG and, in particular, liquid-crystalline phases when the fraction of CEs is above 90% at 37 °C. In model bilayers, CEs condense and nucleate droplets when the CE/phospholipid ratio reaches over 10-15%. This concentration is reduced by TG pre-clusters in the membrane that thereby facilitate CE nucleation. Accordingly, blocking TG synthesis in cells is sufficient to strongly dampen CE LD nucleation. Finally, CE LDs emerged at seipins, which cluster and nucleate TG LDs in the ER. However, when TG synthesis is inhibited, similar numbers of LDs are generated in the presence and absence of seipin, suggesting that seipin controls CE LD formation via its TG clustering capacity. Our data point to a unique model whereby TG pre-clusters, favorable at seipins, catalyze the nucleation of CE LDs.
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21
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Guan Z, Chen J, Liu R, Chen Y, Xing Q, Du Z, Cheng M, Hu J, Zhang W, Mei W, Wan B, Wang Q, Zhang J, Cheng P, Cai H, Cao J, Zhang D, Yan J, Yin P, Hothorn M, Liu Z. The cytoplasmic synthesis and coupled membrane translocation of eukaryotic polyphosphate by signal-activated VTC complex. Nat Commun 2023; 14:718. [PMID: 36759618 PMCID: PMC9911596 DOI: 10.1038/s41467-023-36466-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Accepted: 02/01/2023] [Indexed: 02/11/2023] Open
Abstract
Inorganic polyphosphate (polyP) is an ancient energy metabolite and phosphate store that occurs ubiquitously in all organisms. The vacuolar transporter chaperone (VTC) complex integrates cytosolic polyP synthesis from ATP and polyP membrane translocation into the vacuolar lumen. In yeast and in other eukaryotes, polyP synthesis is regulated by inositol pyrophosphate (PP-InsP) nutrient messengers, directly sensed by the VTC complex. Here, we report the cryo-electron microscopy structure of signal-activated VTC complex at 3.0 Å resolution. Baker's yeast VTC subunits Vtc1, Vtc3, and Vtc4 assemble into a 3:1:1 complex. Fifteen trans-membrane helices form a novel membrane channel enabling the transport of newly synthesized polyP into the vacuolar lumen. PP-InsP binding orients the catalytic polymerase domain at the entrance of the trans-membrane channel, both activating the enzyme and coupling polyP synthesis and membrane translocation. Together with biochemical and cellular studies, our work provides mechanistic insights into the biogenesis of an ancient energy metabolite.
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Affiliation(s)
- Zeyuan Guan
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
| | - Juan Chen
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
| | - Ruiwen Liu
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
| | - Yanke Chen
- Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Qiong Xing
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, 430062, China
| | - Zhangmeng Du
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
| | - Meng Cheng
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
| | - Jianjian Hu
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
| | - Wenhui Zhang
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
| | - Wencong Mei
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
| | - Beijing Wan
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
| | - Qiang Wang
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
| | - Jie Zhang
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
| | - Peng Cheng
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
| | - Huanyu Cai
- College of Science, Huazhong Agricultural University, Wuhan, 430070, China
| | - Jianbo Cao
- Public Laboratory of Electron Microscopy, Huazhong Agricultural University, Wuhan, 430070, China
| | - Delin Zhang
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
| | - Junjie Yan
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
| | - Ping Yin
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
| | - Michael Hothorn
- Structural Plant Biology Laboratory, Department of Plant Scienes, University of Geneva, Geneva, 1211, Switzerland
| | - Zhu Liu
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China.
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22
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Yang S, Miao X, Arnold S, Li B, Ly AT, Wang H, Wang M, Guo X, Pathak MM, Zhao W, Cox CD, Shi Z. Author Correction: Membrane curvature governs the distribution of Piezo1 in live cells. Nat Commun 2023; 14:524. [PMID: 36720871 DOI: 10.1038/s41467-023-36108-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
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23
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Kumar A, Rohe TC, Elrod EJ, Khan AG, Dearborn AD, Kissinger R, Grakoui A, Marcotrigiano J. Regions of hepatitis C virus E2 required for membrane association. Nat Commun 2023; 14:433. [PMID: 36702826 PMCID: PMC9879980 DOI: 10.1038/s41467-023-36183-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Accepted: 01/19/2023] [Indexed: 01/27/2023] Open
Abstract
Hepatitis C virus (HCV) uses a hybrid entry mechanism. Current structural data suggest that upon exposure to low pH and Cluster of Differentiation 81 (CD81), the amino terminus of envelope glycoprotein E2 becomes ordered and releases an internal loop with two invariant aromatic residues into the host membrane. Here, we present the structure of an amino-terminally truncated E2 with the membrane binding loop in a bent conformation and the aromatic side chains sequestered. Comparison with three previously reported E2 structures with the same Fab indicates that this internal loop is flexible, and that local context influences the exposure of hydrophobic residues. Biochemical assays show that the amino-terminally truncated E2 lacks the baseline membrane-binding capacity of the E2 ectodomain. Thus, the amino terminal region is a critical determinant for both CD81 and membrane interaction. These results provide new insights into the HCV entry mechanism.
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Affiliation(s)
- Ashish Kumar
- Structural Virology Section, Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Tiana C Rohe
- Structural Virology Section, Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Elizabeth J Elrod
- Emory National Primate Research Center, Division of Microbiology and Immunology, Emory Vaccine Center, Emory University School of Medicine, Atlanta, GA, 30329, USA
| | - Abdul G Khan
- Center for Advanced Biotechnology and Medicine, Rutgers, The State University of New Jersey, Piscataway, NJ, 08854, USA
| | - Altaira D Dearborn
- Structural Virology Section, Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Ryan Kissinger
- Research Technology Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, 59840, USA
| | - Arash Grakoui
- Emory National Primate Research Center, Division of Microbiology and Immunology, Emory Vaccine Center, Emory University School of Medicine, Atlanta, GA, 30329, USA
| | - Joseph Marcotrigiano
- Structural Virology Section, Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, 20892, USA.
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24
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Su C, Rodriguez-Franco M, Lace B, Nebel N, Hernandez-Reyes C, Liang P, Schulze E, Mymrikov EV, Gross NM, Knerr J, Wang H, Siukstaite L, Keller J, Libourel C, Fischer AAM, Gabor KE, Mark E, Popp C, Hunte C, Weber W, Wendler P, Stanislas T, Delaux PM, Einsle O, Grosse R, Römer W, Ott T. Stabilization of membrane topologies by proteinaceous remorin scaffolds. Nat Commun 2023; 14:323. [PMID: 36658193 PMCID: PMC9852587 DOI: 10.1038/s41467-023-35976-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 01/10/2023] [Indexed: 01/20/2023] Open
Abstract
In plants, the topological organization of membranes has mainly been attributed to the cell wall and the cytoskeleton. Additionally, few proteins, such as plant-specific remorins have been shown to function as protein and lipid organizers. Root nodule symbiosis requires continuous membrane re-arrangements, with bacteria being finally released from infection threads into membrane-confined symbiosomes. We found that mutations in the symbiosis-specific SYMREM1 gene result in highly disorganized perimicrobial membranes. AlphaFold modelling and biochemical analyses reveal that SYMREM1 oligomerizes into antiparallel dimers and may form a higher-order membrane scaffolding structure. This was experimentally confirmed when expressing this and other remorins in wall-less protoplasts is sufficient where they significantly alter and stabilize de novo membrane topologies ranging from membrane blebs to long membrane tubes with a central actin filament. Reciprocally, mechanically induced membrane indentations were equally stabilized by SYMREM1. Taken together we describe a plant-specific mechanism that allows the stabilization of large-scale membrane conformations independent of the cell wall.
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Affiliation(s)
- Chao Su
- Faculty of Biology, University of Freiburg, 79104, Freiburg, Germany
| | | | - Beatrice Lace
- Faculty of Biology, University of Freiburg, 79104, Freiburg, Germany
| | - Nils Nebel
- Faculty of Biology, University of Freiburg, 79104, Freiburg, Germany
| | - Casandra Hernandez-Reyes
- Faculty of Biology, University of Freiburg, 79104, Freiburg, Germany.,CIBSS - Centre of Integrative Biological Signalling Studies, University of Freiburg, 79104, Freiburg, Germany
| | - Pengbo Liang
- Faculty of Biology, University of Freiburg, 79104, Freiburg, Germany
| | - Eija Schulze
- Faculty of Biology, University of Freiburg, 79104, Freiburg, Germany
| | - Evgeny V Mymrikov
- CIBSS - Centre of Integrative Biological Signalling Studies, University of Freiburg, 79104, Freiburg, Germany.,Institute for Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104, Freiburg, Germany
| | - Nikolas M Gross
- CIBSS - Centre of Integrative Biological Signalling Studies, University of Freiburg, 79104, Freiburg, Germany.,Institute for Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104, Freiburg, Germany.,Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, 79104, Freiburg, Germany
| | - Julian Knerr
- Institute of Pharmacology, Medical Faculty, University of Freiburg, 79104, Freiburg, Germany
| | - Hong Wang
- CIBSS - Centre of Integrative Biological Signalling Studies, University of Freiburg, 79104, Freiburg, Germany.,Institute of Pharmacology, Medical Faculty, University of Freiburg, 79104, Freiburg, Germany
| | - Lina Siukstaite
- Faculty of Biology, University of Freiburg, 79104, Freiburg, Germany.,BIOSS - Centre for Biological Signalling Studies, University of Freiburg, 79104, Freiburg, Germany
| | - Jean Keller
- Laboratoire de Recherche en Sciences Végétales (LRSV), Université de Toulouse, CNRS, UPS, INP Toulouse, Castanet Tolosan, France
| | - Cyril Libourel
- Laboratoire de Recherche en Sciences Végétales (LRSV), Université de Toulouse, CNRS, UPS, INP Toulouse, Castanet Tolosan, France
| | - Alexandra A M Fischer
- CIBSS - Centre of Integrative Biological Signalling Studies, University of Freiburg, 79104, Freiburg, Germany.,Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, 79104, Freiburg, Germany.,BIOSS - Centre for Biological Signalling Studies, University of Freiburg, 79104, Freiburg, Germany.,Division of Synthetic Biology, Faculty of Biology, University of Freiburg, 79104, Freiburg, Germany
| | - Katharina E Gabor
- Center for Plant Molecular Biology (ZMBP), University of Tübingen, 72076, Tübingen, Germany
| | - Eric Mark
- Institute of Biochemistry and Biology, Department of Biochemistry, University of Potsdam, 14476, Potsdam-Golm, Germany
| | - Claudia Popp
- Ludwig-Maximilians-University (LMU) Munich, Institute of Genetics, 82152, Martinsried, Germany
| | - Carola Hunte
- CIBSS - Centre of Integrative Biological Signalling Studies, University of Freiburg, 79104, Freiburg, Germany.,Institute for Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104, Freiburg, Germany.,BIOSS - Centre for Biological Signalling Studies, University of Freiburg, 79104, Freiburg, Germany
| | - Wilfried Weber
- CIBSS - Centre of Integrative Biological Signalling Studies, University of Freiburg, 79104, Freiburg, Germany.,BIOSS - Centre for Biological Signalling Studies, University of Freiburg, 79104, Freiburg, Germany.,Division of Synthetic Biology, Faculty of Biology, University of Freiburg, 79104, Freiburg, Germany
| | - Petra Wendler
- Institute of Biochemistry and Biology, Department of Biochemistry, University of Potsdam, 14476, Potsdam-Golm, Germany
| | - Thomas Stanislas
- Center for Plant Molecular Biology (ZMBP), University of Tübingen, 72076, Tübingen, Germany
| | - Pierre-Marc Delaux
- Laboratoire de Recherche en Sciences Végétales (LRSV), Université de Toulouse, CNRS, UPS, INP Toulouse, Castanet Tolosan, France
| | - Oliver Einsle
- Institute of Biochemistry, Faculty of Chemistry, University of Freiburg, 79104, Freiburg, Germany
| | - Robert Grosse
- CIBSS - Centre of Integrative Biological Signalling Studies, University of Freiburg, 79104, Freiburg, Germany.,Institute of Pharmacology, Medical Faculty, University of Freiburg, 79104, Freiburg, Germany
| | - Winfried Römer
- Faculty of Biology, University of Freiburg, 79104, Freiburg, Germany.,CIBSS - Centre of Integrative Biological Signalling Studies, University of Freiburg, 79104, Freiburg, Germany.,BIOSS - Centre for Biological Signalling Studies, University of Freiburg, 79104, Freiburg, Germany
| | - Thomas Ott
- Faculty of Biology, University of Freiburg, 79104, Freiburg, Germany. .,CIBSS - Centre of Integrative Biological Signalling Studies, University of Freiburg, 79104, Freiburg, Germany.
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25
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Anantakrishnan S, Naganathan AN. Thermodynamic architecture and conformational plasticity of GPCRs. Nat Commun 2023; 14:128. [PMID: 36624096 DOI: 10.1038/s41467-023-35790-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 12/29/2022] [Indexed: 01/11/2023] Open
Abstract
G-protein-coupled receptors (GPCRs) are ubiquitous integral membrane proteins involved in diverse cellular signaling processes. Here, we carry out a large-scale ensemble thermodynamic study of 45 ligand-free GPCRs employing a structure-based statistical mechanical framework. We find that multiple partially structured states co-exist in the GPCR native ensemble, with the TM helices 1, 6 and 7 displaying varied folding status, and shaping the conformational landscape. Strongly coupled residues are anisotropically distributed, accounting for only 13% of the residues, illustrating that a large number of residues are inherently dynamic. Active-state GPCRs are characterized by reduced conformational heterogeneity with altered coupling-patterns distributed throughout the structural scaffold. In silico alanine-scanning mutagenesis reveals that extra- and intra-cellular faces of GPCRs are coupled thermodynamically, highlighting an exquisite structural specialization and the fluid nature of the intramolecular interaction network. The ensemble-based perturbation methodology presented here lays the foundation for understanding allosteric mechanisms and the effects of disease-causing mutations in GCPRs.
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26
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Yang S, Miao X, Arnold S, Li B, Ly AT, Wang H, Wang M, Guo X, Pathak MM, Zhao W, Cox CD, Shi Z. Membrane curvature governs the distribution of Piezo1 in live cells. Nat Commun 2022; 13:7467. [PMID: 36463216 DOI: 10.1038/s41467-022-35034-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 11/16/2022] [Indexed: 12/05/2022] Open
Abstract
Piezo1 is a bona fide mechanosensitive ion channel ubiquitously expressed in mammalian cells. The distribution of Piezo1 within a cell is essential for various biological processes including cytokinesis, cell migration, and wound healing. However, the underlying principles that guide the subcellular distribution of Piezo1 remain largely unexplored. Here, we demonstrate that membrane curvature serves as a key regulator of the spatial distribution of Piezo1 in the plasma membrane of living cells. Piezo1 depletes from highly curved membrane protrusions such as filopodia and enriches to nanoscale membrane invaginations. Quantification of the curvature-dependent sorting of Piezo1 directly reveals the in situ nano-geometry of the Piezo1-membrane complex. Piezo1 density on filopodia increases upon activation, independent of calcium, suggesting flattening of the channel upon opening. Consequently, the expression of Piezo1 inhibits filopodia formation, an effect that diminishes with channel activation.
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27
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Jiang Y, Thienpont B, Sapuru V, Hite RK, Dittman JS, Sturgis JN, Scheuring S. Membrane-mediated protein interactions drive membrane protein organization. Nat Commun 2022; 13:7373. [PMID: 36450733 PMCID: PMC9712761 DOI: 10.1038/s41467-022-35202-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 11/22/2022] [Indexed: 12/02/2022] Open
Abstract
The plasma membrane's main constituents, i.e., phospholipids and membrane proteins, are known to be organized in lipid-protein functional domains and supercomplexes. No active membrane-intrinsic process is known to establish membrane organization. Thus, the interplay of thermal fluctuations and the biophysical determinants of membrane-mediated protein interactions must be considered to understand membrane protein organization. Here, we used high-speed atomic force microscopy and kinetic and membrane elastic theory to investigate the behavior of a model membrane protein in oligomerization and assembly in controlled lipid environments. We find that membrane hydrophobic mismatch modulates oligomerization and assembly energetics, and 2D organization. Our experimental and theoretical frameworks reveal how membrane organization can emerge from Brownian diffusion and a minimal set of physical properties of the membrane constituents.
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Affiliation(s)
- Yining Jiang
- Biochemistry & Structural Biology, Cell & Developmental Biology, and Molecular Biology (BCMB) Program, Weill Cornell Graduate School of Biomedical Sciences, 1300 York Avenue, New York, NY 10065 USA ,grid.5386.8000000041936877XWeill Cornell Medicine, Department of Anesthesiology, 1300 York Avenue, New York, NY 10065 USA
| | - Batiste Thienpont
- grid.5399.60000 0001 2176 4817Laboratoire d’Ingénierie des Systèmes Macromoléculaires (LISM), Unité Mixte de Recherche (UMR) 7255, Centre National de la Recherche Scientifique (CNRS), Aix Marseille Université, Marseille, France
| | - Vinay Sapuru
- grid.51462.340000 0001 2171 9952Structural Biology Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065 USA ,Physiology, Biophysics, and Systems Biology (PBSB) Program, Weill Cornell Graduate School of Biomedical Sciences, 1300 York Avenue, New York, NY 10065 USA
| | - Richard K. Hite
- grid.51462.340000 0001 2171 9952Structural Biology Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065 USA
| | - Jeremy S. Dittman
- grid.5386.8000000041936877XWeill Cornell Medicine, Department of Biochemistry, 1300 York Avenue, New York, NY 10065 USA
| | - James N. Sturgis
- grid.5399.60000 0001 2176 4817Laboratoire d’Ingénierie des Systèmes Macromoléculaires (LISM), Unité Mixte de Recherche (UMR) 7255, Centre National de la Recherche Scientifique (CNRS), Aix Marseille Université, Marseille, France
| | - Simon Scheuring
- grid.5386.8000000041936877XWeill Cornell Medicine, Department of Anesthesiology, 1300 York Avenue, New York, NY 10065 USA ,grid.5386.8000000041936877XWeill Cornell Medicine, Department of Physiology and Biophysics, 1300 York Avenue, New York, NY 10065 USA ,grid.5386.8000000041936877XKavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca, NY 14853 USA
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28
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Matthaeus C, Sochacki KA, Dickey AM, Puchkov D, Haucke V, Lehmann M, Taraska JW. The molecular organization of differentially curved caveolae indicates bendable structural units at the plasma membrane. Nat Commun 2022; 13:7234. [PMID: 36433988 PMCID: PMC9700719 DOI: 10.1038/s41467-022-34958-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 11/11/2022] [Indexed: 11/27/2022] Open
Abstract
Caveolae are small coated plasma membrane invaginations with diverse functions. Caveolae undergo curvature changes. Yet, it is unclear which proteins regulate this process. To address this gap, we develop a correlative stimulated emission depletion (STED) fluorescence and platinum replica electron microscopy imaging (CLEM) method to image proteins at single caveolae. Caveolins and cavins are found at all caveolae, independent of curvature. EHD2 is detected at both low and highly curved caveolae. Pacsin2 associates with low curved caveolae and EHBP1 with mostly highly curved caveolae. Dynamin is absent from caveolae. Cells lacking dynamin show no substantial changes to caveolae, suggesting that dynamin is not directly involved in caveolae curvature. We propose a model where caveolins, cavins, and EHD2 assemble as a cohesive structural unit regulated by intermittent associations with pacsin2 and EHBP1. These coats can flatten and curve to enable lipid traffic, signaling, and changes to the surface area of the cell.
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Affiliation(s)
- Claudia Matthaeus
- grid.279885.90000 0001 2293 4638Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD USA
| | - Kem A. Sochacki
- grid.279885.90000 0001 2293 4638Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD USA
| | - Andrea M. Dickey
- grid.279885.90000 0001 2293 4638Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD USA
| | - Dmytro Puchkov
- grid.418832.40000 0001 0610 524XLeibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany
| | - Volker Haucke
- grid.418832.40000 0001 0610 524XLeibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany ,grid.14095.390000 0000 9116 4836Faculty of Biology, Chemistry and Pharmacy, Freie Universität Berlin, Berlin, Germany
| | - Martin Lehmann
- grid.418832.40000 0001 0610 524XLeibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany
| | - Justin W. Taraska
- grid.279885.90000 0001 2293 4638Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD USA
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29
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Muñoz-Gacitúa D, Guzman F, Weiss-López B. Insights into the equilibrium structure and translocation mechanism of TP1, a spontaneous membrane-translocating peptide. Sci Rep 2022; 12:19880. [PMID: 36400938 DOI: 10.1038/s41598-022-23631-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Accepted: 11/02/2022] [Indexed: 11/19/2022] Open
Abstract
Crossing the cellular membrane is one of the main barriers during drug discovery; many potential drugs are rejected for their inability to integrate into the intracell fluid. Although many solutions have been proposed to overcome this barrier, arguably the most promising solution is the use of cell-penetrating peptides. Recently, an array of hydrophobic penetrating peptides was discovered via high throughput screening which proved to be able to cross the membrane passively, and although these peptides proved to be effective at penetrating the cell, the details behind the underlying mechanism of this process remain unknown. In this study, we developed a method to find the equilibrium structure at the transmembrane domain of TP1, a hydrophobic penetrating peptide. In this method, we selectively deuterium-label amino acids in the peptidic chain, and employ results of [Formula: see text]H-NMR spectroscopy to find a molecular dynamics simulation of the peptide that reproduces the experimental results. Effectively finding the equilibrium orientation and dynamics of the peptide in the membrane. We employed this equilibrium structure to simulate the entire translocation mechanism and found that after the peptide reaches its equilibrium structure, it must undergo a two-step mechanism in order to completely translocate the membrane, each step involving the flip-flop of each arginine residue in the peptide. This leads us to conclude that the RLLR motif is essential for the translocating activity of the peptide.
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30
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Frieg B, Antonschmidt L, Dienemann C, Geraets JA, Najbauer EE, Matthes D, de Groot BL, Andreas LB, Becker S, Griesinger C, Schröder GF. The 3D structure of lipidic fibrils of α-synuclein. Nat Commun 2022; 13:6810. [PMID: 36357403 DOI: 10.1038/s41467-022-34552-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 10/21/2022] [Indexed: 11/12/2022] Open
Abstract
α-synuclein misfolding and aggregation into fibrils is a common feature of α-synucleinopathies, such as Parkinson's disease, in which α-synuclein fibrils are a characteristic hallmark of neuronal inclusions called Lewy bodies. Studies on the composition of Lewy bodies extracted postmortem from brain tissue of Parkinson's patients revealed that lipids and membranous organelles are also a significant component. Interactions between α-synuclein and lipids have been previously identified as relevant for Parkinson's disease pathology, however molecular insights into their interactions have remained elusive. Here we present cryo-electron microscopy structures of six α-synuclein fibrils in complex with lipids, revealing specific lipid-fibril interactions. We observe that phospholipids promote an alternative protofilament fold, mediate an unusual arrangement of protofilaments, and fill the central cavities of the fibrils. Together with our previous studies, these structures also indicate a mechanism for fibril-induced lipid extraction, which is likely to be involved in the development of α-synucleinopathies. Specifically, one potential mechanism for the cellular toxicity is the disruption of intracellular vesicles mediated by fibrils and oligomers, and therefore the modulation of these interactions may provide a promising strategy for future therapeutic interventions.
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31
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Winkelmann I, Uzdavinys P, Kenney IM, Brock J, Meier PF, Wagner LM, Gabriel F, Jung S, Matsuoka R, von Ballmoos C, Beckstein O, Drew D. Crystal structure of the Na +/H + antiporter NhaA at active pH reveals the mechanistic basis for pH sensing. Nat Commun 2022; 13:6383. [PMID: 36289233 PMCID: PMC9606361 DOI: 10.1038/s41467-022-34120-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Accepted: 10/14/2022] [Indexed: 12/25/2022] Open
Abstract
The strict exchange of protons for sodium ions across cell membranes by Na+/H+ exchangers is a fundamental mechanism for cell homeostasis. At active pH, Na+/H+ exchange can be modelled as competition between H+ and Na+ to an ion-binding site, harbouring either one or two aspartic-acid residues. Nevertheless, extensive analysis on the model Na+/H+ antiporter NhaA from Escherichia coli, has shown that residues on the cytoplasmic surface, termed the pH sensor, shifts the pH at which NhaA becomes active. It was unclear how to incorporate the pH senor model into an alternating-access mechanism based on the NhaA structure at inactive pH 4. Here, we report the crystal structure of NhaA at active pH 6.5, and to an improved resolution of 2.2 Å. We show that at pH 6.5, residues in the pH sensor rearrange to form new salt-bridge interactions involving key histidine residues that widen the inward-facing cavity. What we now refer to as a pH gate, triggers a conformational change that enables water and Na+ to access the ion-binding site, as supported by molecular dynamics (MD) simulations. Our work highlights a unique, channel-like switch prior to substrate translocation in a secondary-active transporter.
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Affiliation(s)
- Iven Winkelmann
- grid.10548.380000 0004 1936 9377Department of Biochemistry and Biophysics, Science for Life Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Povilas Uzdavinys
- grid.10548.380000 0004 1936 9377Department of Biochemistry and Biophysics, Science for Life Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Ian M. Kenney
- grid.215654.10000 0001 2151 2636Center for Biological Physics and Department of Physics, Arizona State University, Tempe, AZ 85287 USA
| | - Joseph Brock
- grid.10548.380000 0004 1936 9377Department of Biochemistry and Biophysics, Science for Life Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Pascal F. Meier
- grid.10548.380000 0004 1936 9377Department of Biochemistry and Biophysics, Science for Life Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Lina-Marie Wagner
- grid.10548.380000 0004 1936 9377Department of Biochemistry and Biophysics, Science for Life Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Florian Gabriel
- grid.10548.380000 0004 1936 9377Department of Biochemistry and Biophysics, Science for Life Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Sukkyeong Jung
- grid.10548.380000 0004 1936 9377Department of Biochemistry and Biophysics, Science for Life Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Rei Matsuoka
- grid.10548.380000 0004 1936 9377Department of Biochemistry and Biophysics, Science for Life Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Christoph von Ballmoos
- grid.5734.50000 0001 0726 5157Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland
| | - Oliver Beckstein
- grid.215654.10000 0001 2151 2636Center for Biological Physics and Department of Physics, Arizona State University, Tempe, AZ 85287 USA
| | - David Drew
- grid.10548.380000 0004 1936 9377Department of Biochemistry and Biophysics, Science for Life Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
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32
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Manioglu S, Modaresi SM, Ritzmann N, Thoma J, Overall SA, Harms A, Upert G, Luther A, Barnes AB, Obrecht D, Müller DJ, Hiller S. Antibiotic polymyxin arranges lipopolysaccharide into crystalline structures to solidify the bacterial membrane. Nat Commun 2022; 13:6195. [PMID: 36271003 PMCID: PMC9587031 DOI: 10.1038/s41467-022-33838-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2022] [Accepted: 10/04/2022] [Indexed: 12/24/2022] Open
Abstract
Polymyxins are last-resort antibiotics with potent activity against multi-drug resistant pathogens. They interact with lipopolysaccharide (LPS) in bacterial membranes, but mechanistic details at the molecular level remain unclear. Here, we characterize the interaction of polymyxins with native, LPS-containing outer membrane patches of Escherichia coli by high-resolution atomic force microscopy imaging, along with structural and biochemical assays. We find that polymyxins arrange LPS into hexagonal assemblies to form crystalline structures. Formation of the crystalline structures is correlated with the antibiotic activity, and absent in polymyxin-resistant strains. Crystal lattice parameters alter with variations of the LPS and polymyxin molecules. Quantitative measurements show that the crystalline structures decrease membrane thickness and increase membrane area as well as stiffness. Together, these findings suggest the formation of rigid LPS-polymyxin crystals and subsequent membrane disruption as the mechanism of polymyxin action and provide a benchmark for optimization and de novo design of LPS-targeting antimicrobials.
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Affiliation(s)
- Selen Manioglu
- Department of Biosystems Science and Engineering, Eidgenössische Technische Hochschule (ETH) Zürich, Mattenstrasse 26, Basel, Switzerland
| | | | - Noah Ritzmann
- Department of Biosystems Science and Engineering, Eidgenössische Technische Hochschule (ETH) Zürich, Mattenstrasse 26, Basel, Switzerland
| | - Johannes Thoma
- Department of Chemistry and Molecular Biology, University of Gothenburg, Göteborg, Sweden
| | - Sarah A Overall
- Laboratory of Physical Chemistry, ETH Zurich, Zurich, Switzerland
| | - Alexander Harms
- Biozentrum, University of Basel, Spitalstrasse 41, Basel, Switzerland
| | | | | | | | | | - Daniel J Müller
- Department of Biosystems Science and Engineering, Eidgenössische Technische Hochschule (ETH) Zürich, Mattenstrasse 26, Basel, Switzerland.
| | - Sebastian Hiller
- Biozentrum, University of Basel, Spitalstrasse 41, Basel, Switzerland.
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33
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Yang F, Cabe MH, Ogle SD, Sanchez V, Langert KA. Optimization of critical parameters for coating of polymeric nanoparticles with plasma membrane vesicles by sonication. Sci Rep 2021; 11:23996. [PMID: 34907240 DOI: 10.1038/s41598-021-03422-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 12/01/2021] [Indexed: 11/17/2022] Open
Abstract
Top-down functionalization of nanoparticles with cellular membranes imparts nanoparticles with enhanced bio-interfacing capabilities. Initial methods for membrane coating involved physical co-extrusion of nanoparticles and membrane vesicles through a porous membrane; however, recent works employ sonication as the disruptive force to reform membranes around the surface of nanoparticles. Although sonication is widely used, there remains a paucity of information on the effects of sonication variables on coating efficiency, leading to inconsistent membrane coating across studies. In this work, we present a systematic analysis of the sonication parameters that influence the membrane coating. The results showed that sonication amplitude, time, temperature, membrane ratio, sample volume, and density need to be considered in order to optimize membrane coating of polymeric nanoparticles.
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34
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de Araújo Pimenta L, Duarte EL, Muniz GSV, Pasqualoto KFM, de Mattos Fontes MR, Lamy MT, Sampaio SC. Correlating biological activity to thermo-structural analysis of the interaction of CTX with synthetic models of macrophage membranes. Sci Rep 2021; 11:23712. [PMID: 34887428 DOI: 10.1038/s41598-021-02552-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Accepted: 11/11/2021] [Indexed: 11/10/2022] Open
Abstract
The important pharmacological actions of Crotoxin (CTX) on macrophages, the main toxin in the venom of Crotalus durissus terrificus, and its important participation in the control of different pathophysiological processes, have been demonstrated. The biological activities performed by macrophages are related to signaling mediated by receptors expressed on the membrane surface of these cells or opening and closing of ion channels, generation of membrane curvature and pore formation. In the present work, the interaction of the CTX complex with the cell membrane of macrophages is studied, both using biological cells and synthetic lipid membranes to monitor structural alterations induced by the protein. Here we show that CTX can penetrate THP-1 cells and induce pores only in anionic lipid model membranes, suggesting that a possible access pathway for CTX to the cell is via lipids with anionic polar heads. Considering that the selectivity of the lipid composition varies in different tissues and organs of the human body, the thermostructural studies presented here are extremely important to open new investigations on the biological activities of CTX in different biological systems.
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35
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Zhang S, Ren Q, Novick SJ, Strutzenberg TS, Griffin PR, Bao H. One-step construction of circularized nanodiscs using SpyCatcher-SpyTag. Nat Commun 2021; 12:5451. [PMID: 34521837 PMCID: PMC8440770 DOI: 10.1038/s41467-021-25737-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 08/26/2021] [Indexed: 02/07/2023] Open
Abstract
Circularized nandiscs (cNDs) exhibit superb monodispersity and have the potential to transform functional and structural studies of membrane proteins. In particular, cNDs can stabilize large patches of lipid bilayers for the reconstitution of complex membrane biochemical reactions, enabling the capture of crucial intermediates involved in synaptic transmission and viral entry. However, previous methods for building cNDs require multiple steps and suffer from low yields. We herein introduce a simple, one-step approach to ease the construction of cNDs using the SpyCatcher-SpyTag technology. This approach increases the yield of cNDs by over 10-fold and is able to rapidly generates cNDs with diameters ranging from 11 to over 100 nm. We demonstrate the utility of these cNDs for mechanistic interrogations of vesicle fusion and protein-lipid interactions that are unattainable using small nanodiscs. Together, the remarkable performance of SpyCatcher-SpyTag in nanodisc circularization paves the way for the use of cNDs in membrane biochemistry and structural biology.
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Affiliation(s)
- Shanwen Zhang
- Department of Molecular Medicine, The Scripps Research Institute, Jupiter, Florida, USA
| | - Qian Ren
- Department of Molecular Medicine, The Scripps Research Institute, Jupiter, Florida, USA
| | - Scott J Novick
- Department of Molecular Medicine, The Scripps Research Institute, Jupiter, Florida, USA
| | | | - Patrick R Griffin
- Department of Molecular Medicine, The Scripps Research Institute, Jupiter, Florida, USA.
| | - Huan Bao
- Department of Molecular Medicine, The Scripps Research Institute, Jupiter, Florida, USA.
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36
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Stauffer M, Ucurum Z, Harder D, Fotiadis D. Engineering and functional characterization of a proton-driven β-lactam antibiotic translocation module for bionanotechnological applications. Sci Rep 2021; 11:17205. [PMID: 34446740 PMCID: PMC8390754 DOI: 10.1038/s41598-021-96298-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2021] [Accepted: 07/23/2021] [Indexed: 12/02/2022] Open
Abstract
Novel approaches in synthetic biology focus on the bottom-up modular assembly of natural, modified natural or artificial components into molecular systems with functionalities not found in nature. A possible application for such techniques is the bioremediation of natural water sources contaminated with small organic molecules (e.g., drugs and pesticides). A simple molecular system to actively accumulate and degrade pollutants could be a bionanoreactor composed of a liposome or polymersome scaffold combined with energizing- (e.g., light-driven proton pump), transporting- (e.g., proton-driven transporter) and degrading modules (e.g., enzyme). This work focuses on the engineering of a transport module specific for β-lactam antibiotics. We previously solved the crystal structure of a bacterial peptide transporter, which allowed us to improve the affinity for certain β-lactam antibiotics using structure-based mutagenesis combined with a bacterial uptake assay. We were able to identify specific mutations, which enhanced the affinity of the transporter for antibiotics containing certain structural features. Screening of potential compounds allowed for the identification of a β-lactam antibiotic ligand with relatively high affinity. Transport of antibiotics was evaluated using a solid-supported membrane electrophysiology assay. In summary, we have engineered a proton-driven β-lactam antibiotic translocation module, contributing to the growing toolset for bionanotechnological applications.
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Affiliation(s)
- Mirko Stauffer
- Institute of Biochemistry and Molecular Medicine, University of Bern, 3012, Bern, Switzerland
| | - Zöhre Ucurum
- Institute of Biochemistry and Molecular Medicine, University of Bern, 3012, Bern, Switzerland
| | - Daniel Harder
- Institute of Biochemistry and Molecular Medicine, University of Bern, 3012, Bern, Switzerland
| | - Dimitrios Fotiadis
- Institute of Biochemistry and Molecular Medicine, University of Bern, 3012, Bern, Switzerland.
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37
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Otrin L, Witkowska A, Marušič N, Zhao Z, Lira RB, Kyrilis FL, Hamdi F, Ivanov I, Lipowsky R, Kastritis PL, Dimova R, Sundmacher K, Jahn R, Vidaković-Koch T. En route to dynamic life processes by SNARE-mediated fusion of polymer and hybrid membranes. Nat Commun 2021; 12:4972. [PMID: 34404795 PMCID: PMC8371082 DOI: 10.1038/s41467-021-25294-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 07/30/2021] [Indexed: 12/11/2022] Open
Abstract
A variety of artificial cells springs from the functionalization of liposomes with proteins. However, these models suffer from low durability without repair and replenishment mechanisms, which can be partly addressed by replacing the lipids with polymers. Yet natural membranes are also dynamically remodeled in multiple cellular processes. Here, we show that synthetic amphiphile membranes also undergo fusion, mediated by the protein machinery for synaptic secretion. We integrated fusogenic SNAREs in polymer and hybrid vesicles and observed efficient membrane and content mixing. We determined bending rigidity and pore edge tension as key parameters for fusion and described its plausible progression through cryo-EM snapshots. These findings demonstrate that dynamic membrane phenomena can be reconstituted in synthetic materials, thereby providing new tools for the assembly of synthetic protocells.
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Affiliation(s)
- Lado Otrin
- Electrochemical Energy Conversion, Max Planck Institute for Dynamics of Complex Technical Systems, Magdeburg, Germany.
| | - Agata Witkowska
- Laboratory of Neurobiology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
- Department of Molecular Pharmacology and Cell Biology, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany
| | - Nika Marušič
- Process Systems Engineering, Max Planck Institute for Dynamics of Complex Technical Systems, Magdeburg, Germany
| | - Ziliang Zhao
- Department of Theory and Bio-Systems, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
| | - Rafael B Lira
- Department of Theory and Bio-Systems, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
- Moleculaire Biofysica, Zernike Instituut, Rijksuniversiteit Groningen, Groningen, Netherlands
| | - Fotis L Kyrilis
- Interdisciplinary Research Center HALOmem & Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Biozentrum, Halle/Saale, Germany
| | - Farzad Hamdi
- Interdisciplinary Research Center HALOmem & Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Biozentrum, Halle/Saale, Germany
| | - Ivan Ivanov
- Process Systems Engineering, Max Planck Institute for Dynamics of Complex Technical Systems, Magdeburg, Germany
| | - Reinhard Lipowsky
- Department of Theory and Bio-Systems, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
| | - Panagiotis L Kastritis
- Interdisciplinary Research Center HALOmem & Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Biozentrum, Halle/Saale, Germany
| | - Rumiana Dimova
- Department of Theory and Bio-Systems, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
| | - Kai Sundmacher
- Process Systems Engineering, Max Planck Institute for Dynamics of Complex Technical Systems, Magdeburg, Germany
| | - Reinhard Jahn
- Laboratory of Neurobiology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Tanja Vidaković-Koch
- Electrochemical Energy Conversion, Max Planck Institute for Dynamics of Complex Technical Systems, Magdeburg, Germany
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38
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Abstract
The endoplasmic reticulum (ER) is a eukaryotic subcellular organelle composed of tubules and sheet-like areas of membrane connected at junctions. The tubule network is highly dynamic and undergoes rapid and continual rearrangement. There are currently few tools to evaluate network organisation and dynamics. We quantified ER network organisation in Vero and MRC5 cells, and developed an analysis workflow for dynamics of established tubules in live cells. The persistence length, tubule length, junction coordination number and angles of the network were quantified. Hallmarks of imbalances in ER tension, indications of interactions with microtubules and other subcellular organelles, and active dynamics were observed. Clear differences in dynamic behaviour were observed for established tubules at different positions within the cell using itemset mining. We found that tubules with activity-driven fluctuations were more likely to be located away from the cell periphery and a population of peripheral tubules with no signs of active motion was found.
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Affiliation(s)
- Hannah T Perkins
- Biological Physics, Department of Physics and Astronomy, Schuster Building, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK
- Division of Molecular and Cellular Function, School of Biological Sciences, Michael Smith Building, The University of Manchester, Dover Street, Manchester, M13 9PT, UK
| | - Victoria J Allan
- Division of Molecular and Cellular Function, School of Biological Sciences, Michael Smith Building, The University of Manchester, Dover Street, Manchester, M13 9PT, UK.
| | - Thomas A Waigh
- Biological Physics, Department of Physics and Astronomy, Schuster Building, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK.
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39
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White P, Haysom SF, Iadanza MG, Higgins AJ, Machin JM, Whitehouse JM, Horne JE, Schiffrin B, Carpenter-Platt C, Calabrese AN, Storek KM, Rutherford ST, Brockwell DJ, Ranson NA, Radford SE. The role of membrane destabilisation and protein dynamics in BAM catalysed OMP folding. Nat Commun 2021; 12:4174. [PMID: 34234105 DOI: 10.1038/s41467-021-24432-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 06/08/2021] [Indexed: 02/06/2023] Open
Abstract
The folding of β-barrel outer membrane proteins (OMPs) in Gram-negative bacteria is catalysed by the β-barrel assembly machinery (BAM). How lateral opening in the β-barrel of the major subunit BamA assists in OMP folding, and the contribution of membrane disruption to BAM catalysis remain unresolved. Here, we use an anti-BamA monoclonal antibody fragment (Fab1) and two disulphide-crosslinked BAM variants (lid-locked (LL), and POTRA-5-locked (P5L)) to dissect these roles. Despite being lethal in vivo, we show that all complexes catalyse folding in vitro, albeit less efficiently than wild-type BAM. CryoEM reveals that while Fab1 and BAM-P5L trap an open-barrel state, BAM-LL contains a mixture of closed and contorted, partially-open structures. Finally, all three complexes globally destabilise the lipid bilayer, while BamA does not, revealing that the BAM lipoproteins are required for this function. Together the results provide insights into the role of BAM structure and lipid dynamics in OMP folding.
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40
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Arumugam S, Schmieder S, Pezeshkian W, Becken U, Wunder C, Chinnapen D, Ipsen JH, Kenworthy AK, Lencer W, Mayor S, Johannes L. Ceramide structure dictates glycosphingolipid nanodomain assembly and function. Nat Commun 2021; 12:3675. [PMID: 34135326 PMCID: PMC8209009 DOI: 10.1038/s41467-021-23961-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 05/28/2021] [Indexed: 02/08/2023] Open
Abstract
Gangliosides in the outer leaflet of the plasma membrane of eukaryotic cells are essential for many cellular functions and pathogenic interactions. How gangliosides are dynamically organized and how they respond to ligand binding is poorly understood. Using fluorescence anisotropy imaging of synthetic, fluorescently labeled GM1 gangliosides incorporated into the plasma membrane of living cells, we found that GM1 with a fully saturated C16:0 acyl chain, but not with unsaturated C16:1 acyl chain, is actively clustered into nanodomains, which depends on membrane cholesterol, phosphatidylserine and actin. The binding of cholera toxin B-subunit (CTxB) leads to enlarged membrane domains for both C16:0 and C16:1, owing to binding of multiple GM1 under a toxin, and clustering of CTxB. The structure of the ceramide acyl chain still affects these domains, as co-clustering with the glycosylphosphatidylinositol (GPI)-anchored protein CD59 occurs only when GM1 contains the fully saturated C16:0 acyl chain, and not C16:1. Thus, different ceramide species of GM1 gangliosides dictate their assembly into nanodomains and affect nanodomain structure and function, which likely underlies many endogenous cellular processes.
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Affiliation(s)
- Senthil Arumugam
- Institut Curie, PSL Research University, U1143 INSERM, UMR3666 CNRS, Cellular and Chemical Biology unit, Paris, Cedex, France
- National Centre for Biological Sciences (NCBS), Bangalore, India
- Monash Biomedicine Discovery Institute, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton/Melbourne, VIC, Australia
- European Molecular Biological Laboratory Australia (EMBL Australia), Monash University, Clayton/ Melbourne, VIC, Australia
| | - Stefanie Schmieder
- Division of Gastroenterology, Boston Children's Hospital, Boston, MA, USA
| | - Weria Pezeshkian
- Groningen Biomolecular Sciences and Biotechnology Institute and Zernike Institute for Advanced Materials, University of Groningen, Groningen, Netherlands
| | - Ulrike Becken
- Institut Curie, PSL Research University, U1143 INSERM, UMR3666 CNRS, Cellular and Chemical Biology unit, Paris, Cedex, France
| | - Christian Wunder
- Institut Curie, PSL Research University, U1143 INSERM, UMR3666 CNRS, Cellular and Chemical Biology unit, Paris, Cedex, France
| | - Dan Chinnapen
- Division of Gastroenterology, Boston Children's Hospital, Boston, MA, USA
| | - John Hjort Ipsen
- MEMPHYS/PhyLife, Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Odense M, Denmark
| | - Anne K Kenworthy
- Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, VA, USA
| | - Wayne Lencer
- Division of Gastroenterology, Boston Children's Hospital, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
- Harvard Digestive Diseases Center, Boston, MA, USA
| | - Satyajit Mayor
- National Centre for Biological Sciences (NCBS), Bangalore, India.
| | - Ludger Johannes
- Institut Curie, PSL Research University, U1143 INSERM, UMR3666 CNRS, Cellular and Chemical Biology unit, Paris, Cedex, France.
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41
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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: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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42
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Brooks RL, Mistry CS, Dixon AM. Curvature sensing amphipathic helix in the C-terminus of RTNLB13 is conserved in all endoplasmic reticulum shaping reticulons in Arabidopsis thaliana. Sci Rep 2021; 11:6326. [PMID: 33737685 PMCID: PMC7973432 DOI: 10.1038/s41598-021-85866-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 03/05/2021] [Indexed: 11/24/2022] Open
Abstract
The reticulon family of integral membrane proteins are conserved across all eukaryotes and typically localize to the endoplasmic reticulum (ER), where they are involved in generating highly-curved tubules. We recently demonstrated that Reticulon-like protein B13 (RTNLB13) from Arabidopsis thaliana contains a curvature-responsive amphipathic helix (APH) important for the proteins' ability to induce curvature in the ER membrane, but incapable of generating curvature by itself. We suggested it acts as a feedback element, only folding/binding once a sufficient degree of curvature has been achieved, and stabilizes curvature without disrupting the bilayer. However, it remains unclear whether this is unique to RTNLB13 or is conserved across all reticulons-to date, experimental evidence has only been reported for two reticulons. Here we used biophysical methods to characterize a minimal library of putative APH peptides from across the 21 A. thaliana isoforms. We found that reticulons with the closest evolutionary relationship to RTNLB13 contain curvature-sensing APHs in the same location with sequence conservation. Our data reveal that a more distantly-related branch of reticulons developed a ~ 20-residue linker between the transmembrane domain and APH. This may facilitate functional flexibility as previous studies have linked these isoforms not only to ER remodeling but other cellular activities.
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Affiliation(s)
- Rhiannon L Brooks
- MAS Centre for Doctoral Training, University of Warwick, Coventry, CV4 7AL, UK
- Department of Chemistry, University of Warwick, Coventry, CV4 7AL, UK
| | - Chandni S Mistry
- Department of Chemistry, University of Warwick, Coventry, CV4 7AL, UK
| | - Ann M Dixon
- Department of Chemistry, University of Warwick, Coventry, CV4 7AL, UK.
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43
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Rohwedder A, Knipp S, Roberts LD, Ladbury JE. Composition of receptor tyrosine kinase-mediated lipid micro-domains controlled by adaptor protein interaction. Sci Rep 2021; 11:6160. [PMID: 33731760 PMCID: PMC7969938 DOI: 10.1038/s41598-021-85578-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 03/03/2021] [Indexed: 11/25/2022] Open
Abstract
Receptor tyrosine kinases (RTKs) are highly regulated, single pass transmembrane proteins, fundamental to cellular function and survival. Aberrancies in regulation lead to corruption of signal transduction and a range of pathological outcomes. Although control mechanisms associated with the receptors and their ligands are well understood, little is known with respect to the impact of lipid/lipid and lipid/protein interactions in the proximal plasma membrane environment. Given that the transmembrane regions of RTKs change in response to extracellular ligand binding, the lipid interactions have important consequences in influencing signal transduction. Fibroblast growth factor receptor 2 (FGFR2) is a highly regulated RTK, including under basal conditions. Binding of the adaptor protein, growth factor receptor-bound protein 2 (GRB2) to FGFR2 prevents full activation and recruitment of downstream signalling effector proteins in the absence of extracellular stimulation. Here we demonstrate that the FGFR2-GRB2 complex is sustained in a defined lipid environment. Dissociation of GRB2 from this complex due to ligand binding, or reduced GRB2 expression, facilitates the dispersion of FGFR2 into detergent-resistant membrane (DRM) micro-domains. This modification of the plasma membrane proximal to FGFR2 provides a further regulatory checkpoint which controls receptor degradation, recycling and recruitment of intracellular signalling proteins.
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Affiliation(s)
- Arndt Rohwedder
- School of Molecular and Cellular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Sabine Knipp
- School of Molecular and Cellular Biology, University of Leeds, Leeds, LS2 9JT, UK
- School of Applied Sciences, University of Huddersfield, Huddersfield, HD1 3DH, UK
| | - Lee D Roberts
- Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, LS29JT, UK
| | - John E Ladbury
- School of Molecular and Cellular Biology, University of Leeds, Leeds, LS2 9JT, UK.
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44
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Gelenter MD, Mandala VS, Niesen MJM, Sharon DA, Dregni AJ, Willard AP, Hong M. Water orientation and dynamics in the closed and open influenza B virus M2 proton channels. Commun Biol 2021; 4:338. [PMID: 33712696 PMCID: PMC7955094 DOI: 10.1038/s42003-021-01847-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Accepted: 02/11/2021] [Indexed: 01/03/2023] Open
Abstract
The influenza B M2 protein forms a water-filled tetrameric channel to conduct protons across the lipid membrane. To understand how channel water mediates proton transport, we have investigated the water orientation and dynamics using solid-state NMR spectroscopy and molecular dynamics (MD) simulations. 13C-detected water 1H NMR relaxation times indicate that water has faster rotational motion in the low-pH open channel than in the high-pH closed channel. Despite this faster dynamics, the open-channel water shows higher orientational order, as manifested by larger motionally-averaged 1H chemical shift anisotropies. MD simulations indicate that this order is induced by the cationic proton-selective histidine at low pH. Furthermore, the water network has fewer hydrogen-bonding bottlenecks in the open state than in the closed state. Thus, faster dynamics and higher orientational order of water molecules in the open channel establish the water network structure that is necessary for proton hopping.
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Affiliation(s)
- Martin D Gelenter
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Venkata S Mandala
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Michiel J M Niesen
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Dina A Sharon
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Aurelio J Dregni
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Adam P Willard
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Mei Hong
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA.
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45
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Zhang S, Zhou J, Zhang Y, Liu T, Friedel P, Zhuo W, Somasekharan S, Roy K, Zhang L, Liu Y, Meng X, Deng H, Zeng W, Li G, Forbush B, Yang M. The structural basis of function and regulation of neuronal cotransporters NKCC1 and KCC2. Commun Biol 2021; 4:226. [PMID: 33597714 PMCID: PMC7889885 DOI: 10.1038/s42003-021-01750-w] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 01/22/2021] [Indexed: 11/08/2022] Open
Abstract
NKCC and KCC transporters mediate coupled transport of Na++K++Cl- and K++Cl- across the plasma membrane, thus regulating cell Cl- concentration and cell volume and playing critical roles in transepithelial salt and water transport and in neuronal excitability. The function of these transporters has been intensively studied, but a mechanistic understanding has awaited structural studies of the transporters. Here, we present the cryo-electron microscopy (cryo-EM) structures of the two neuronal cation-chloride cotransporters human NKCC1 (SLC12A2) and mouse KCC2 (SLC12A5), along with computational analysis and functional characterization. These structures highlight essential residues in ion transport and allow us to propose mechanisms by which phosphorylation regulates transport activity.
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Affiliation(s)
- Sensen Zhang
- Ministry of Education Key Laboratory of Protein Science, Tsinghua-Peking Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Jun Zhou
- Ministry of Education Key Laboratory of Protein Science, Tsinghua-Peking Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Yuebin Zhang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China
| | - Tianya Liu
- Ministry of Education Key Laboratory of Protein Science, Tsinghua-Peking Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Perrine Friedel
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT, USA
| | - Wei Zhuo
- Ministry of Education Key Laboratory of Protein Science, Tsinghua-Peking Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Suma Somasekharan
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT, USA
| | - Kasturi Roy
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT, USA
| | - Laixing Zhang
- Ministry of Education Key Laboratory of Protein Science, Tsinghua-Peking Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Yang Liu
- Ministry of Education Key Laboratory of Protein Science, Tsinghua-Peking Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Xianbin Meng
- MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing, China
| | - Haiteng Deng
- MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing, China
| | - Wenwen Zeng
- Center for Life Sciences, Institute for Immunology and School of Medicine, Tsinghua University, Beijing, China
| | - Guohui Li
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China.
| | - Biff Forbush
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT, USA.
| | - Maojun Yang
- Ministry of Education Key Laboratory of Protein Science, Tsinghua-Peking Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China.
- School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
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46
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Ortega JKE, Mohan RP, Munoz CM, Sridhar SL, Vernerey FJ. Helical growth during the phototropic response, avoidance response, and in stiff mutants of Phycomyces blakesleeanus. Sci Rep 2021; 11:3653. [PMID: 33574466 DOI: 10.1038/s41598-021-83254-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Accepted: 02/01/2021] [Indexed: 01/30/2023] Open
Abstract
The sporangiophores of Phycomyces blakesleeanus have been used as a model system to study sensory transduction, helical growth, and to establish global biophysical equations for expansive growth of walled cells. More recently, local statistical biophysical models of the cell wall are being constructed to better understand the molecular underpinnings of helical growth and its behavior during the many growth responses of the sporangiophores to sensory stimuli. Previous experimental and theoretical findings guide the development of these local models. Future development requires an investigation of explicit and implicit assumptions made in the prior research. Here, experiments are conducted to test three assumptions made in prior research, that (a) elongation rate, (b) rotation rate, and (c) helical growth steepness, R, of the sporangiophore remain constant during the phototropic response (bending toward unilateral light) and the avoidance response (bending away from solid barriers). The experimental results reveal that all three assumptions are incorrect for the phototropic response and probably incorrect for the avoidance response but the results are less conclusive. Generally, the experimental results indicate that the elongation and rotation rates increase during these responses, as does R, indicating that the helical growth steepness become flatter. The implications of these findings on prior research, the "fibril reorientation and slippage" hypothesis, global biophysical equations, and local statistical biophysical models are discussed.
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47
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Canepa E, Salassi S, Simonelli F, Ferrando R, Rolandi R, Lambruschini C, Canepa F, Dante S, Relini A, Rossi G. Non-disruptive uptake of anionic and cationic gold nanoparticles in neutral zwitterionic membranes. Sci Rep 2021; 11:1256. [PMID: 33441958 PMCID: PMC7807088 DOI: 10.1038/s41598-020-80953-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 12/18/2020] [Indexed: 11/16/2022] Open
Abstract
The potential toxicity of ligand-protected nanoparticles (NPs) on biological targets is crucial for their clinical translation. A number of studies are aimed at investigating the molecular mechanisms shaping the interactions between synthetic NPs and neutral plasma membranes. The role played by the NP surface charge is still widely debated. We compare, via liposome leakage assays, the perturbation induced by the penetration of sub-6 nm anionic and cationic Au NPs into model neutral lipid membranes composed of the zwitterionic 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC). Our charged Au NPs are functionalized by a mixture of the apolar 1-octanethiol and a ω-charged thiol which is either the anionic 11-mercapto-1-undecanesulfonate or the cationic (11-mercaptoundecyl)-N,N,N-trimethylammonium. In both cases, the NP uptake in the bilayer is confirmed by quartz crystal microbalance investigations. Our leakage assays show that both negatively and positively charged Au NPs do not induce significant membrane damage on POPC liposomes when penetrating into the bilayer. By means of molecular dynamics simulations, we show that the energy barrier for membrane penetration is the same for both NPs. These results suggest that the sign of the NP surface charge, per se, does not imply different physicochemical mechanisms of interaction with zwitterionic lipid membranes.
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Affiliation(s)
- Ester Canepa
- Department of Chemistry and Industrial Chemistry, University of Genoa, 16146, Genoa, Italy
| | | | | | | | - Ranieri Rolandi
- Department of Physics, University of Genoa, 16146, Genoa, Italy
| | - Chiara Lambruschini
- Department of Chemistry and Industrial Chemistry, University of Genoa, 16146, Genoa, Italy
| | - Fabio Canepa
- Department of Chemistry and Industrial Chemistry, University of Genoa, 16146, Genoa, Italy
| | - Silvia Dante
- Materials Characterization Facility, Italian Institute of Technology, 16163, Genoa, Italy
| | - Annalisa Relini
- Department of Physics, University of Genoa, 16146, Genoa, Italy.
| | - Giulia Rossi
- Department of Physics, University of Genoa, 16146, Genoa, Italy.
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48
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Shen C, Mao C, Xu C, Jin N, Zhang H, Shen DD, Shen Q, Wang X, Hou T, Chen Z, Rondard P, Pin JP, Zhang Y, Liu J. Structural basis of GABA B receptor-G i protein coupling. Nature 2021; 594:594-598. [PMID: 33911284 PMCID: PMC8222003 DOI: 10.1038/s41586-021-03507-1] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Accepted: 03/29/2021] [Indexed: 02/03/2023]
Abstract
G-protein-coupled receptors (GPCRs) have central roles in intercellular communication1,2. Structural studies have revealed how GPCRs can activate G proteins. However, whether this mechanism is conserved among all classes of GPCR remains unknown. Here we report the structure of the class-C heterodimeric GABAB receptor, which is activated by the inhibitory transmitter GABA, in its active form complexed with Gi1 protein. We found that a single G protein interacts with the GB2 subunit of the GABAB receptor at a site that mainly involves intracellular loop 2 on the side of the transmembrane domain. This is in contrast to the G protein binding in a central cavity, as has been observed with other classes of GPCR. This binding mode results from the active form of the transmembrane domain of this GABAB receptor being different from that of other GPCRs, as it shows no outside movement of transmembrane helix 6. Our work also provides details of the inter- and intra-subunit changes that link agonist binding to G-protein activation in this heterodimeric complex.
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Affiliation(s)
- Cangsong Shen
- grid.33199.310000 0004 0368 7223ZJU-HUST Joint Laboratory of Cellular Signaling, Key Laboratory of Molecular Biophysics of MOE, International Research Center for Sensory Biology and Technology of MOST, College of Life Science and Technology, Huazhong University of Science and Technology (HUST), Wuhan, China ,grid.13402.340000 0004 1759 700XDepartment of Biophysics and Department of Pathology of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China ,grid.13402.340000 0004 1759 700XLiangzhu Laboratory, Zhejiang University Medical Center, Hangzhou, China
| | - Chunyou Mao
- grid.13402.340000 0004 1759 700XDepartment of Biophysics and Department of Pathology of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China ,grid.13402.340000 0004 1759 700XLiangzhu Laboratory, Zhejiang University Medical Center, Hangzhou, China ,Zhejiang Provincial Key Laboratory of Immunity and Inflammatory Diseases, Hangzhou, China
| | - Chanjuan Xu
- grid.33199.310000 0004 0368 7223ZJU-HUST Joint Laboratory of Cellular Signaling, Key Laboratory of Molecular Biophysics of MOE, International Research Center for Sensory Biology and Technology of MOST, College of Life Science and Technology, Huazhong University of Science and Technology (HUST), Wuhan, China ,grid.508040.9Bioland Laboratory, Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou, China
| | - Nan Jin
- grid.33199.310000 0004 0368 7223ZJU-HUST Joint Laboratory of Cellular Signaling, Key Laboratory of Molecular Biophysics of MOE, International Research Center for Sensory Biology and Technology of MOST, College of Life Science and Technology, Huazhong University of Science and Technology (HUST), Wuhan, China ,grid.13402.340000 0004 1759 700XDepartment of Biophysics and Department of Pathology of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China ,grid.13402.340000 0004 1759 700XLiangzhu Laboratory, Zhejiang University Medical Center, Hangzhou, China
| | - Huibing Zhang
- grid.13402.340000 0004 1759 700XDepartment of Biophysics and Department of Pathology of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China ,grid.13402.340000 0004 1759 700XLiangzhu Laboratory, Zhejiang University Medical Center, Hangzhou, China ,Zhejiang Provincial Key Laboratory of Immunity and Inflammatory Diseases, Hangzhou, China
| | - Dan-Dan Shen
- grid.13402.340000 0004 1759 700XDepartment of Biophysics and Department of Pathology of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China ,grid.13402.340000 0004 1759 700XLiangzhu Laboratory, Zhejiang University Medical Center, Hangzhou, China ,Zhejiang Provincial Key Laboratory of Immunity and Inflammatory Diseases, Hangzhou, China
| | - Qingya Shen
- grid.13402.340000 0004 1759 700XDepartment of Biophysics and Department of Pathology of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China ,grid.13402.340000 0004 1759 700XLiangzhu Laboratory, Zhejiang University Medical Center, Hangzhou, China ,Zhejiang Provincial Key Laboratory of Immunity and Inflammatory Diseases, Hangzhou, China
| | - Xiaomei Wang
- grid.33199.310000 0004 0368 7223ZJU-HUST Joint Laboratory of Cellular Signaling, Key Laboratory of Molecular Biophysics of MOE, International Research Center for Sensory Biology and Technology of MOST, College of Life Science and Technology, Huazhong University of Science and Technology (HUST), Wuhan, China
| | - Tingjun Hou
- grid.13402.340000 0004 1759 700XInnovation Institute for Artificial Intelligence in Medicine of Zhejiang University, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
| | - Zhong Chen
- grid.268505.c0000 0000 8744 8924Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, Zhejiang Chinese Medical University, Hangzhou, China
| | - Philippe Rondard
- grid.121334.60000 0001 2097 0141Institut de Génomique Fonctionnelle (IGF), Université de Montpellier, CNRS, INSERM, 34094 Montpellier, France
| | - Jean-Philippe Pin
- grid.121334.60000 0001 2097 0141Institut de Génomique Fonctionnelle (IGF), Université de Montpellier, CNRS, INSERM, 34094 Montpellier, France
| | - Yan Zhang
- grid.13402.340000 0004 1759 700XDepartment of Biophysics and Department of Pathology of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China ,grid.13402.340000 0004 1759 700XLiangzhu Laboratory, Zhejiang University Medical Center, Hangzhou, China ,Zhejiang Provincial Key Laboratory of Immunity and Inflammatory Diseases, Hangzhou, China ,grid.13402.340000 0004 1759 700XMOE Frontier Science Center for Brain Research and Brain-Machine Integration, Zhejiang University School of Medicine, Hangzhou, China
| | - Jianfeng Liu
- grid.33199.310000 0004 0368 7223ZJU-HUST Joint Laboratory of Cellular Signaling, Key Laboratory of Molecular Biophysics of MOE, International Research Center for Sensory Biology and Technology of MOST, College of Life Science and Technology, Huazhong University of Science and Technology (HUST), Wuhan, China ,grid.508040.9Bioland Laboratory, Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou, China
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49
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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50
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Schröder V, Rău I, Dobrin N, Stefanov C, Mihali CV, Pădureţu CC, Apetroaei MR. Micromorphological details and identification of chitinous wall structures in Rapana venosa (Gastropoda, Mollusca) egg capsules. Sci Rep 2020; 10:14550. [PMID: 32883987 PMCID: PMC7471954 DOI: 10.1038/s41598-020-71348-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Accepted: 08/09/2020] [Indexed: 11/08/2022] Open
Abstract
The present study evaluated the structural and ultrastructural characteristics of Rapana venosa egg capsules, starting from observations of their antifouling activity and mechanical resistance to water currents in mid-shore habitats. Optical microscopy, epifluorescence, and electron microscopy were used to evaluate the surface and structure of the R. venosa egg capsules. These measurements revealed an internal multilamellar structure of the capsule wall with in-plane distributions of layers with various orientations. It was found that the walls contained vacuolar structures in the median layer, which provided the particular characteristics. Mechanical, viscoelastic and swelling measurements were also carried out. This study revealed the presence and distribution of chitosan in the capsule of R. venosa. Chitosan identification in the egg capsule wall structure was carried out through SEM-EDX measurements, colorimetric assays, FT-IR spectra and physical-chemical tests. The biopolymer presence in the capsule walls may explain the properties of their surfaces as well as the mechanical resistance of the capsule and its resistance to chemical variations in the living environment.
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Affiliation(s)
- Verginica Schröder
- Department of Cellular and Molecular Biology, Faculty of Pharmacy, "Ovidius" University, Capitan Aviator Al. Serbanescu Street No. 6, Campus C, Constanta, Romania
| | - Ileana Rău
- Department of General Chemistry, Faculty of Applied Chemistry and Materials Science, University Politehnica of Bucharest, Polizu Street No. 1, Bucharest, Romania.
| | - Nicolae Dobrin
- Electron Microscopy Department and Center for Research and Development of the Morphological and Genetic Studies of Malignant Pathology, "Ovidius" University, University Street No. 1, Campus B, Constanta, Romania
| | - Constanţa Stefanov
- Electron Microscopy Department and Center for Research and Development of the Morphological and Genetic Studies of Malignant Pathology, "Ovidius" University, University Street No. 1, Campus B, Constanta, Romania
| | - Ciprian-Valentin Mihali
- Department of Life Sciences, Faculty of Medicine, "Vasile Goldiș" Western University From Arad, Arad, Romania
| | - Carla-Cezarina Pădureţu
- Department of General Chemistry, Faculty of Applied Chemistry and Materials Science, University Politehnica of Bucharest, Polizu Street No. 1, Bucharest, Romania
| | - Manuela Rossemary Apetroaei
- Department of Naval and Port Engineering and Management, "Mircea Cel Batran" Naval Academy, Fulgerului Street No. 1, Constanta, Romania
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