1
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Amati A, Moning SU, Javor S, Schär S, Deutschmann S, Reymond JL, von Ballmoos C. Overcoming Protein Orientation Mismatch Enables Efficient Nanoscale Light-Driven ATP Production. ACS Synth Biol 2024; 13:1355-1364. [PMID: 38569139 PMCID: PMC11036485 DOI: 10.1021/acssynbio.4c00058] [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: 01/29/2024] [Revised: 03/12/2024] [Accepted: 03/14/2024] [Indexed: 04/05/2024]
Abstract
Adenosine triphosphate (ATP)-producing modules energized by light-driven proton pumps are powerful tools for the bottom-up assembly of artificial cell-like systems. However, the maximum efficiency of such modules is prohibited by the random orientation of the proton pumps during the reconstitution process into lipid-surrounded nanocontainers. Here, we overcome this limitation using a versatile approach to uniformly orient the light-driven proton pump proteorhodopsin (pR) in liposomes. pR is post-translationally either covalently or noncovalently coupled to a membrane-impermeable protein domain guiding orientation during insertion into preformed liposomes. In the second scenario, we developed a novel bifunctional linker, trisNTA-SpyTag, that allows for the reversible connection of any SpyCatcher-containing protein and a HisTag-carrying protein. The desired protein orientations are verified by monitoring vectorial proton pumping and membrane potential generation. In conjunction with ATP synthase, highly efficient ATP production is energized by the inwardly pumping population. In comparison to other light-driven ATP-producing modules, the uniform orientation allows for maximal rates at economical protein concentrations. The presented technology is highly customizable and not limited to light-driven proton pumps but applicable to many membrane proteins and offers a general approach to overcome orientation mismatch during membrane reconstitution, requiring little to no genetic modification of the protein of interest.
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Affiliation(s)
| | | | - Sacha Javor
- Department of Chemistry, Biochemistry
and Pharmaceutical Sciences, University
of Bern, Freiestrasse 3, 3012 Bern, Switzerland
| | - Sandra Schär
- Department of Chemistry, Biochemistry
and Pharmaceutical Sciences, University
of Bern, Freiestrasse 3, 3012 Bern, Switzerland
| | | | - Jean-Louis Reymond
- Department of Chemistry, Biochemistry
and Pharmaceutical Sciences, University
of Bern, Freiestrasse 3, 3012 Bern, Switzerland
| | - Christoph von Ballmoos
- Department of Chemistry, Biochemistry
and Pharmaceutical Sciences, University
of Bern, Freiestrasse 3, 3012 Bern, Switzerland
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2
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Young MR, Heit S, Bublitz M. Structure, function and biogenesis of the fungal proton pump Pma1. Biochim Biophys Acta Mol Cell Res 2024; 1871:119600. [PMID: 37741574 DOI: 10.1016/j.bbamcr.2023.119600] [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] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 08/19/2023] [Accepted: 09/18/2023] [Indexed: 09/25/2023]
Abstract
The fungal plasma membrane proton pump Pma1 is an integral plasma membrane protein of the P-type ATPase family. It is an essential enzyme responsible for maintaining a constant cytosolic pH and for energising the plasma membrane to secondary transport processes. Due to its importance for fungal survival and absence from animals, Pma1 is also a highly sought-after drug target. Until recently, its characterisation has been limited to functional, mutational and localisation studies, due to a lack of high-resolution structural information. The determination of three cryo-EM structures of Pma1 in its unique hexameric state offers a new level of understanding the molecular mechanisms underlying the protein's stability, regulated activity and druggability. In light of this context, this article aims to review what we currently know about the structure, function and biogenesis of fungal Pma1.
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Affiliation(s)
- Margaret R Young
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom
| | - Sabine Heit
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom
| | - Maike Bublitz
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom.
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3
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Goel N, Srivastav S, Patel A, Shirsath A, Panda TR, Patra M, Feist AM, Anand A. TCA cycle tailoring facilitates optimal growth of proton-pumping NADH dehydrogenase-dependent Escherichia coli. Microbiol Spectr 2023; 11:e0222523. [PMID: 37855642 PMCID: PMC10715208 DOI: 10.1128/spectrum.02225-23] [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: 05/26/2023] [Accepted: 09/12/2023] [Indexed: 10/20/2023] Open
Abstract
IMPORTANCE Energy generation pathways are a potential avenue for the development of novel antibiotics. However, bacteria possess remarkable resilience due to the compensatory pathways, which presents a challenge in this direction. NADH, the primary reducing equivalent, can transfer electrons to two distinct types of NADH dehydrogenases. Type I NADH dehydrogenase is an enzyme complex comprising multiple subunits and can generate proton motive force (PMF). Type II NADH dehydrogenase does not pump protons but plays a crucial role in maintaining the turnover of NAD+. To study the adaptive rewiring of energy metabolism, we evolved an Escherichia coli mutant lacking type II NADH dehydrogenase. We discovered that by modifying the flux through the tricarboxylic acid (TCA) cycle, E. coli could mitigate the growth impairment observed in the absence of type II NADH dehydrogenase. This research provides valuable insights into the intricate mechanisms employed by bacteria to compensate for disruptions in energy metabolism.
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Affiliation(s)
- Nikita Goel
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, Maharashtra, India
| | - Stuti Srivastav
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, Maharashtra, India
| | - Arjun Patel
- Department of Bioengineering, University of California, San Diego, La Jolla, California, USA
| | - Akshay Shirsath
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, Maharashtra, India
| | - Tushar Ranjan Panda
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai, Maharashtra, India
| | - Malay Patra
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai, Maharashtra, India
| | - Adam M. Feist
- Department of Bioengineering, University of California, San Diego, La Jolla, California, USA
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet, Kongens, Lyngby, Denmark
| | - Amitesh Anand
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, Maharashtra, India
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4
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Solebo O, Ling L, Nwankwo I, Zhou J, Fu TM, Ke H. Plasmodium falciparum utilizes pyrophosphate to fuel an essential proton pump in the ring stage and the transition to trophozoite stage. PLoS Pathog 2023; 19:e1011818. [PMID: 38048362 PMCID: PMC10732439 DOI: 10.1371/journal.ppat.1011818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 12/20/2023] [Accepted: 11/10/2023] [Indexed: 12/06/2023] Open
Abstract
During asexual growth and replication cycles inside red blood cells, the malaria parasite Plasmodium falciparum primarily relies on glycolysis for energy supply, as its single mitochondrion performs little or no oxidative phosphorylation. Post merozoite invasion of a host red blood cell, the ring stage lasts approximately 20 hours and was traditionally thought to be metabolically quiescent. However, recent studies have shown that the ring stage is active in several energy-costly processes, including gene transcription, protein translation, protein export, and movement inside the host cell. It has remained unclear whether a low glycolytic flux alone can meet the energy demand of the ring stage over a long period post invasion. Here, we demonstrate that the metabolic by-product pyrophosphate (PPi) is a critical energy source for the development of the ring stage and its transition to the trophozoite stage. During early phases of the asexual development, the parasite utilizes Plasmodium falciparum vacuolar pyrophosphatase 1 (PfVP1), an ancient pyrophosphate-driven proton pump, to export protons across the parasite plasma membrane. Conditional deletion of PfVP1 leads to a delayed ring stage that lasts nearly 48 hours and a complete blockage of the ring-to-trophozoite transition before the onset of parasite death. This developmental arrest can be partially rescued by an orthologous vacuolar pyrophosphatase from Arabidopsis thaliana, but not by the soluble pyrophosphatase from Saccharomyces cerevisiae, which lacks proton pumping activities. Since proton-pumping pyrophosphatases have been evolutionarily lost in human hosts, the essentiality of PfVP1 suggests its potential as an antimalarial drug target. A drug target of the ring stage is highly desired, as current antimalarials have limited efficacy against this stage.
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Affiliation(s)
- Omobukola Solebo
- Center for Molecular Parasitology, Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Liqin Ling
- Center for Molecular Parasitology, Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania, United States of America
- Department of Laboratory Medicine, West China Hospital, Sichuan University, Chengdu, China
| | - Ikechukwu Nwankwo
- Center for Molecular Parasitology, Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Jing Zhou
- Department of Laboratory Medicine, West China Hospital, Sichuan University, Chengdu, China
| | - Tian-Min Fu
- Department of Biological Chemistry and Pharmacology, The Ohio State University College of Medicine, Columbus, Ohio, United States of America
- The Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio, United States of America
| | - Hangjun Ke
- Center for Molecular Parasitology, Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania, United States of America
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5
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Strauss J, Deng L, Gao S, Toseland A, Bachy C, Zhang C, Kirkham A, Hopes A, Utting R, Joest EF, Tagliabue A, Löw C, Worden AZ, Nagel G, Mock T. Plastid-localized xanthorhodopsin increases diatom biomass and ecosystem productivity in iron-limited surface oceans. Nat Microbiol 2023; 8:2050-2066. [PMID: 37845316 PMCID: PMC10627834 DOI: 10.1038/s41564-023-01498-5] [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: 02/24/2023] [Accepted: 09/12/2023] [Indexed: 10/18/2023]
Abstract
Microbial rhodopsins are photoreceptor proteins that convert light into biological signals or energy. Proteins of the xanthorhodopsin family are common in eukaryotic photosynthetic plankton including diatoms. However, their biological role in these organisms remains elusive. Here we report on a xanthorhodopsin variant (FcR1) isolated from the polar diatom Fragilariopsis cylindrus. Applying a combination of biophysical, biochemical and reverse genetics approaches, we demonstrate that FcR1 is a plastid-localized proton pump which binds the chromophore retinal and is activated by green light. Enhanced growth of a Thalassiora pseudonana gain-of-function mutant expressing FcR1 under iron limitation shows that the xanthorhodopsin proton pump supports growth when chlorophyll-based photosynthesis is iron-limited. The abundance of xanthorhodopsin transcripts in natural diatom communities of the surface oceans is anticorrelated with the availability of dissolved iron. Thus, we propose that these proton pumps convey a fitness advantage in regions where phytoplankton growth is limited by the availability of dissolved iron.
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Affiliation(s)
- Jan Strauss
- School of Environmental Sciences, University of East Anglia, Norwich Research Park, Norwich, UK.
- Ocean EcoSystems Biology Unit, RD3, GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany.
- European Molecular Biology Laboratory (EMBL), Hamburg Unit c/o Deutsches Elektronen Synchrotron (DESY), Hamburg, Germany.
- Centre for Structural Systems Biology (CSSB), Hamburg, Germany.
- German Maritime Centre, Hamburg, Germany.
| | - Longji Deng
- School of Environmental Sciences, University of East Anglia, Norwich Research Park, Norwich, UK
| | - Shiqiang Gao
- Department of Neurophysiology, Institute of Physiology, University of Würzburg, Wuerzburg, Germany
| | - Andrew Toseland
- School of Environmental Sciences, University of East Anglia, Norwich Research Park, Norwich, UK
| | - Charles Bachy
- Ocean EcoSystems Biology Unit, RD3, GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
- Sorbonne Université, CNRS, FR2424, Station biologique de Roscoff, Roscoff, France
| | - Chong Zhang
- Department of Neurophysiology, Institute of Physiology, University of Würzburg, Wuerzburg, Germany
| | - Amy Kirkham
- School of Environmental Sciences, University of East Anglia, Norwich Research Park, Norwich, UK
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, UK
| | - Amanda Hopes
- School of Environmental Sciences, University of East Anglia, Norwich Research Park, Norwich, UK
| | - Robert Utting
- School of Environmental Sciences, University of East Anglia, Norwich Research Park, Norwich, UK
| | - Eike F Joest
- Department of Biology, Biocenter, University of Würzburg, Wuerzburg, Germany
| | | | - Christian Löw
- European Molecular Biology Laboratory (EMBL), Hamburg Unit c/o Deutsches Elektronen Synchrotron (DESY), Hamburg, Germany
- Centre for Structural Systems Biology (CSSB), Hamburg, Germany
| | - Alexandra Z Worden
- Ocean EcoSystems Biology Unit, RD3, GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
- Max Planck Institute for Evolutionary Biology, Plön, Germany
- Marine Biological Laboratory, Woods Hole, MA, USA
| | - Georg Nagel
- Department of Neurophysiology, Institute of Physiology, University of Würzburg, Wuerzburg, Germany
| | - Thomas Mock
- School of Environmental Sciences, University of East Anglia, Norwich Research Park, Norwich, UK.
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6
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Abe K, Nishizawa T, Artigas P. An unusual conformation from Na +-sensitive non-gastric proton pump mutants reveals molecular mechanisms of cooperative Na +-binding. Biochim Biophys Acta Mol Cell Res 2023; 1870:119543. [PMID: 37482134 DOI: 10.1016/j.bbamcr.2023.119543] [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] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 06/29/2023] [Accepted: 07/14/2023] [Indexed: 07/25/2023]
Abstract
The Na+,K+-ATPase (NKA) and non-gastric H+,K+- ATPase (ngHKA) share ~65 % sequence identity, and nearly identical catalytic cycles. These pumps alternate between inward-facing (E1) and outward-facing (E2) conformations and differ in their exported substrate (Na+ or H+) and stoichiometries (3 Na+:2 K+ or 1 H+:1 K+). We reported that structures of the NKA-mimetic ngHKA mutant K794S/A797P/W940/R949C (SPWC) with 2 K+ occluded in E2-Pi and 3 Na+-bound in E1·ATP states were nearly identical to NKA structures in equivalent states. Here we report the cryo-EM structures of K794A and K794S, two poorly-selective ngHKA mutants, under conditions to stabilize the E1·ATP state. Unexpectedly, the structures show a hybrid with both E1- and E2-like structural features. While transmembrane segments TM1-TM3 and TM4's extracellular half adopted an E2-like conformation, the rest of the protein assumed an E1 configuration. Two spherical densities, likely bound Na+, were observed at cation-binding sites I and III, without density at site II. This explains the E2-like conformation of TM4's exoplasmic half. In NKA, oxygen atoms derived from the unwound portion of TM4 coordinated Na+ at site II. Thus, the lack of Na+ at site II of K794A/S prevents the luminal portion of TM4 from taking an E1-like position. The K794A structure also suggests that incomplete coordination of Na+ at site III induces the halfway rotation of TM6, which impairs Na+-binding at the site II. Thus, our observations provide insight into the molecular mechanism of E2-E1 transition and cooperative Na+-binding in the NKA and other related cation pumps.
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Affiliation(s)
- Kazuhiro Abe
- Graduate School of Pharmaceutical Sciences, Nagoya University, Nagoya 464-8601, Japan; Cellular and Structural Physiology Institute, Nagoya University, Nagoya 464-8601, Japan; Center for One Medicine Innovative Translational Research, Gifu University Institute for Advanced Study, Japan.
| | - Tomohiro Nishizawa
- Graduate School of Medical Life Sciences, Yokohama City University, Tsurumi, Yokohama 230-0045, Japan
| | - Pablo Artigas
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX, USA
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7
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Petrovskaya LE, Siletsky SA, Mamedov MD, Lukashev EP, Balashov SP, Dolgikh DA, Kirpichnikov MP. Features of the Mechanism of Proton Transport in ESR, Retinal Protein from Exiguobacterium sibiricum. Biochemistry Moscow 2023; 88:1544-1554. [PMID: 38105023 DOI: 10.1134/s0006297923100103] [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] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 07/11/2023] [Accepted: 07/11/2023] [Indexed: 12/19/2023]
Abstract
Retinal-containing light-sensitive proteins - rhodopsins - are found in many microorganisms. Interest in them is largely explained by their role in light energy storage and photoregulation in microorganisms, as well as the prospects for their use in optogenetics to control neuronal activity, including treatment of various diseases. One of the representatives of microbial rhodopsins is ESR, the retinal protein of Exiguobacterium sibiricum. What distinguishes ESR from homologous proteins is the presence of a lysine residue (Lys96) as a proton donor for the Schiff base. This feature, along with the hydrogen bond of the proton acceptor Asp85 with the His57 residue, determines functional characteristics of ESR as a proton pump. This review examines the results of ESR studies conducted using various methods, including direct electrometry. Comparison of the obtained data with the results of structural studies and with other retinal proteins allows us to draw conclusions about the mechanisms of transport of hydrogen ions in ESR and similar retinal proteins.
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Affiliation(s)
- Lada E Petrovskaya
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia.
| | - Sergei A Siletsky
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119992, Russia
| | - Mahir D Mamedov
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119992, Russia
| | - Eugene P Lukashev
- Faculty of Biology, Lomonosov Moscow State University, Moscow, 119234, Russia
| | - Sergei P Balashov
- Department of Physiology and Biophysics, University of California, Irvine, CA 92697
| | - Dmitry A Dolgikh
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia
- Faculty of Biology, Lomonosov Moscow State University, Moscow, 119234, Russia
| | - Mikhail P Kirpichnikov
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia
- Faculty of Biology, Lomonosov Moscow State University, Moscow, 119234, Russia
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8
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Palmgren M. Evolution of the sodium pump. Biochim Biophys Acta Mol Cell Res 2023; 1870:119511. [PMID: 37301269 DOI: 10.1016/j.bbamcr.2023.119511] [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] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 05/16/2023] [Accepted: 06/02/2023] [Indexed: 06/12/2023]
Abstract
Eukaryotic plasma membranes (PMs) are energized by electrogenic P-type ATPases that generate either Na+ or H+ motive forces to drive Na+ and H+ dependent transport processes, respectively. For this purpose, animal rely on Na+/K+-ATPases whereas fungi and plants employ PM H+-ATPases. Prokaryotes, on the other hand, depend on H+ or Na+-motive electron transport complexes to energize their cell membranes. This raises the question as to why and when electrogenic Na+ and H+ pumps evolved? Here it is shown that prokaryotic Na+/K+-ATPases have near perfect conservation of binding sites involved in coordination of three Na+ and two K+ ions. Such pumps are rare in Eubacteria but are common in methanogenic Archaea where they often are found together with P-type putative PM H+-ATPases. With some exceptions, Na+/K+-ATPases and PM H+-ATPases are found everywhere in the eukaryotic tree of life, but never together in animals, fungi and land plants. It is hypothesized that Na+/K+-ATPases and PM H+-ATPases evolved in methanogenic Archaea to support the bioenergetics of these ancestral organisms, which can utilize both H+ and Na+ as energy currencies. Both pumps must have been simultaneously present in the first eukaryotic cell, but during diversification of the major eukaryotic kingdoms, and at the time animals diverged from fungi, animals kept Na+/K+-ATPases but lost PM H+-ATPases. At the same evolutionary branch point, fungi did loose Na+/K+-ATPases, and their role was taken over by PM H+-ATPases. An independent but similar scenery emerged during terrestrialization of plants: they lost Na+/K+-ATPases but kept PM H+-ATPases.
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Affiliation(s)
- Michael Palmgren
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Denmark.
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9
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Kim H, Saura P, Pöverlein MC, Gamiz-Hernandez AP, Kaila VRI. Quinone Catalysis Modulates Proton Transfer Reactions in the Membrane Domain of Respiratory Complex I. J Am Chem Soc 2023; 145:17075-17086. [PMID: 37490414 PMCID: PMC10416309 DOI: 10.1021/jacs.3c03086] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2023] [Indexed: 07/27/2023]
Abstract
Complex I is a redox-driven proton pump that drives electron transport chains and powers oxidative phosphorylation across all domains of life. Yet, despite recently resolved structures from multiple organisms, it still remains unclear how the redox reactions in Complex I trigger proton pumping up to 200 Å away from the active site. Here, we show that the proton-coupled electron transfer reactions during quinone reduction drive long-range conformational changes of conserved loops and trans-membrane (TM) helices in the membrane domain of Complex I from Yarrowia lipolytica. We find that the conformational switching triggers a π → α transition in a TM helix (TM3ND6) and establishes a proton pathway between the quinone chamber and the antiporter-like subunits, responsible for proton pumping. Our large-scale (>20 μs) atomistic molecular dynamics (MD) simulations in combination with quantum/classical (QM/MM) free energy calculations show that the helix transition controls the barrier for proton transfer reactions by wetting transitions and electrostatic effects. The conformational switching is enabled by re-arrangements of ion pairs that propagate from the quinone binding site to the membrane domain via an extended network of conserved residues. We find that these redox-driven changes create a conserved coupling network within the Complex I superfamily, with point mutations leading to drastic activity changes and mitochondrial disorders. On a general level, our findings illustrate how catalysis controls large-scale protein conformational changes and enables ion transport across biological membranes.
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Affiliation(s)
- Hyunho Kim
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm 10691, Sweden
| | - Patricia Saura
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm 10691, Sweden
| | | | - Ana P. Gamiz-Hernandez
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm 10691, Sweden
| | - Ville R. I. Kaila
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm 10691, Sweden
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10
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Abdelgied M, Uhl K, Chen OG, Schultz C, Tripp K, Peraino AM, Paithankar S, Chen B, Tamae Kakazu M, Castillo Bahena A, Jager TE, Lawson C, Chesla DW, Pestov N, Modyanov NN, Prokop J, Neubig RR, Uhal BD, Girgis RE, Li X. Targeting ATP12A, a Nongastric Proton Pump α Subunit, for Idiopathic Pulmonary Fibrosis Treatment. Am J Respir Cell Mol Biol 2023; 68:638-650. [PMID: 36780662 PMCID: PMC10257074 DOI: 10.1165/rcmb.2022-0264oc] [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: 07/05/2022] [Accepted: 02/13/2023] [Indexed: 02/15/2023] Open
Abstract
Idiopathic pulmonary fibrosis (IPF) is a pathological condition of unknown etiology that results from injury to the lung and an ensuing fibrotic response that leads to the thickening of the alveolar walls and obliteration of the alveolar space. The pathogenesis is not clear, and there are currently no effective therapies for IPF. Small airway disease and mucus accumulation are prominent features in IPF lungs, similar to cystic fibrosis lung disease. The ATP12A gene encodes the α-subunit of the nongastric H+, K+-ATPase, which functions to acidify the airway surface fluid and impairs mucociliary transport function in patients with cystic fibrosis. It is hypothesized that the ATP12A protein may play a role in the pathogenesis of IPF. The authors' studies demonstrate that ATP12A protein is overexpressed in distal small airways from the lungs of patients with IPF compared with normal human lungs. In addition, overexpression of the ATP12A protein in mouse lungs worsened bleomycin induced experimental pulmonary fibrosis. This was prevented by a potassium competitive proton pump blocker, vonoprazan. These data support the concept that the ATP12A protein plays an important role in the pathogenesis of lung fibrosis. Inhibition of the ATP12A protein has potential as a novel therapeutic strategy in IPF treatment.
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Affiliation(s)
| | - Katie Uhl
- Department of Pediatrics and Human Development and
| | | | - Chad Schultz
- Department of Pediatrics and Human Development and
| | - Kaylie Tripp
- Department of Pediatrics and Human Development and
| | | | | | - Bin Chen
- Department of Pediatrics and Human Development and
- Department of Pharmacology and Toxicology and
| | - Maximiliano Tamae Kakazu
- Department of Medicine, College of Human Medicine, Michigan State University, Grand Rapids, Michigan
- Division of Pulmonary and Critical Care Medicine
| | | | - Tara E. Jager
- Richard Devos Heart and Lung Transplant Program, Spectrum Health, Grand Rapids, Michigan
| | - Cameron Lawson
- Richard Devos Heart and Lung Transplant Program, Spectrum Health, Grand Rapids, Michigan
| | | | - Nikolay Pestov
- Department of Physiology and Pharmacology and Center for Diabetes and Endocrine Research, College of Medicine, University of Toledo, Health Science Campus, Toledo, Ohio
| | - Nikolai N. Modyanov
- Department of Physiology and Pharmacology and Center for Diabetes and Endocrine Research, College of Medicine, University of Toledo, Health Science Campus, Toledo, Ohio
| | - Jeremy Prokop
- Department of Pediatrics and Human Development and
- Department of Pharmacology and Toxicology and
| | | | - Bruce D. Uhal
- Department of Physiology, Michigan State University, East Lansing, Michigan; and
| | - Reda E. Girgis
- Department of Medicine, College of Human Medicine, Michigan State University, Grand Rapids, Michigan
- Division of Pulmonary and Critical Care Medicine
- Richard Devos Heart and Lung Transplant Program, Spectrum Health, Grand Rapids, Michigan
| | - Xiaopeng Li
- Department of Pediatrics and Human Development and
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11
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Chazan A, Das I, Fujiwara T, Murakoshi S, Rozenberg A, Molina-Márquez A, Sano FK, Tanaka T, Gómez-Villegas P, Larom S, Pushkarev A, Malakar P, Hasegawa M, Tsukamoto Y, Ishizuka T, Konno M, Nagata T, Mizuno Y, Katayama K, Abe-Yoshizumi R, Ruhman S, Inoue K, Kandori H, León R, Shihoya W, Yoshizawa S, Sheves M, Nureki O, Béjà O. Phototrophy by antenna-containing rhodopsin pumps in aquatic environments. Nature 2023; 615:535-540. [PMID: 36859551 DOI: 10.1038/s41586-023-05774-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 01/31/2023] [Indexed: 03/03/2023]
Abstract
Energy transfer from light-harvesting ketocarotenoids to the light-driven proton pump xanthorhodopsins has been previously demonstrated in two unique cases: an extreme halophilic bacterium1 and a terrestrial cyanobacterium2. Attempts to find carotenoids that bind and transfer energy to abundant rhodopsin proton pumps3 from marine photoheterotrophs have thus far failed4-6. Here we detected light energy transfer from the widespread hydroxylated carotenoids zeaxanthin and lutein to the retinal moiety of xanthorhodopsins and proteorhodopsins using functional metagenomics combined with chromophore extraction from the environment. The light-harvesting carotenoids transfer up to 42% of the harvested energy in the violet- or blue-light range to the green-light absorbing retinal chromophore. Our data suggest that these antennas may have a substantial effect on rhodopsin phototrophy in the world's lakes, seas and oceans. However, the functional implications of our findings are yet to be discovered.
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Affiliation(s)
- Ariel Chazan
- Faculty of Biology, Technion-Israel Institute of Technology, Haifa, Israel
| | - Ishita Das
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot, Israel
| | - Takayoshi Fujiwara
- Atmosphere and Ocean Research Institute, The University of Tokyo, Chiba, Japan
| | - Shunya Murakoshi
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Andrey Rozenberg
- Faculty of Biology, Technion-Israel Institute of Technology, Haifa, Israel
| | - Ana Molina-Márquez
- Laboratory of Biochemistry and Molecular Biology, Faculty of Experimental Sciences, Marine International Campus of Excellence (CEIMAR), University of Huelva, Huelva, Spain
| | - Fumiya K Sano
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Tatsuki Tanaka
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Patricia Gómez-Villegas
- Laboratory of Biochemistry and Molecular Biology, Faculty of Experimental Sciences, Marine International Campus of Excellence (CEIMAR), University of Huelva, Huelva, Spain
| | - Shirley Larom
- Faculty of Biology, Technion-Israel Institute of Technology, Haifa, Israel
| | - Alina Pushkarev
- Faculty of Biology, Technion-Israel Institute of Technology, Haifa, Israel
- Institute for Biology, Experimental Biophysics, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Partha Malakar
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Masumi Hasegawa
- Atmosphere and Ocean Research Institute, The University of Tokyo, Chiba, Japan
- Institute for Extra-cutting-edge Science and Technology Avant-garde Research (X-star), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Kanagawa, Japan
| | - Yuya Tsukamoto
- Atmosphere and Ocean Research Institute, The University of Tokyo, Chiba, Japan
| | - Tomohiro Ishizuka
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa, Japan
| | - Masae Konno
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa, Japan
| | - Takashi Nagata
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa, Japan
| | - Yosuke Mizuno
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Nagoya, Japan
| | - Kota Katayama
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Nagoya, Japan
- OptoBioTechnology Research Center, Nagoya Institute of Technology, Nagoya, Japan
| | - Rei Abe-Yoshizumi
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Nagoya, Japan
| | - Sanford Ruhman
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Keiichi Inoue
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa, Japan
| | - Hideki Kandori
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Nagoya, Japan
- OptoBioTechnology Research Center, Nagoya Institute of Technology, Nagoya, Japan
| | - Rosa León
- Laboratory of Biochemistry and Molecular Biology, Faculty of Experimental Sciences, Marine International Campus of Excellence (CEIMAR), University of Huelva, Huelva, Spain
| | - Wataru Shihoya
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan.
| | - Susumu Yoshizawa
- Atmosphere and Ocean Research Institute, The University of Tokyo, Chiba, Japan.
| | - Mordechai Sheves
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot, Israel.
| | - Osamu Nureki
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan.
| | - Oded Béjà
- Faculty of Biology, Technion-Israel Institute of Technology, Haifa, Israel.
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Michalak A, Wdowikowska A, Janicka M. Plant Plasma Membrane Proton Pump: One Protein with Multiple Functions. Cells 2022; 11:cells11244052. [PMID: 36552816 PMCID: PMC9777500 DOI: 10.3390/cells11244052] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 12/13/2022] [Accepted: 12/13/2022] [Indexed: 12/23/2022] Open
Abstract
In plants, the plasma membrane proton pump (PM H+-ATPase) regulates numerous transport-dependent processes such as growth, development, basic physiology, and adaptation to environmental conditions. This review explores the multifunctionality of this enzyme in plant cells. The abundance of several PM H+-ATPase isogenes and their pivotal role in energizing transport in plants have been connected to the phenomena of pleiotropy. The multifunctionality of PM H+-ATPase is a focal point of numerous studies unraveling the molecular mechanisms of plant adaptation to adverse environmental conditions. Furthermore, PM H+-ATPase is a key element in plant defense mechanisms against pathogen attack; however, it also functions as a target for pathogens that enable plant tissue invasion. Here, we provide an extensive review of the PM H+-ATPase as a multitasking protein in plants. We focus on the results of recent studies concerning PM H+-ATPase and its role in plant growth, physiology, and pathogenesis.
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13
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Kawasaki Y, Konno M, Inoue K. Kinetic study on the molecular mechanism of light-driven inward proton transport by schizorhodopsins. Biochim Biophys Acta Biomembr 2022; 1864:184016. [PMID: 35931184 DOI: 10.1016/j.bbamem.2022.184016] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 06/28/2022] [Accepted: 07/14/2022] [Indexed: 06/15/2023]
Abstract
Schizorhodopsins (SzRs) are light-driven inward proton pumping membrane proteins. A H+ is released to the cytoplasmic solvent from the chromophore, retinal Schiff base (RSB), after light absorption, and then another H+ is bound to the RSB at the end of photocyclic reaction. However, the mechanistic detail of H+ transfers in SzR is almost unknown. Here we studied the deuterium isotope effect and the temperature dependence of the reaction rate constants of elementary steps in the photocycles of SzRs. The former indicated that deprotonation and reprotonation of RSB is mainly accomplished by H+ hopping between heavy atoms with similar H+ affinity. Furthermore, the temperature dependence of the rate constants revealed that most of H+ transfer events have a high entropy barrier. In contrast, the activation enthalpy and entropy of extremely thermostable SzR (MsSzR) are significantly higher than other types of SzRs (SzR1 and MtSzR) suggesting that its highly thermostable structure is optimized with at the cost of slower reaction rates at ambient temperatures.
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Affiliation(s)
- Yuma Kawasaki
- The Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan
| | - Masae Konno
- The Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan; PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
| | - Keiichi Inoue
- The Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan.
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14
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Qiu D, Zhu C, Fan R, Mao G, Wu P, Zeng J. Arsenic inhibits citric acid accumulation via downregulating vacuolar proton pump gene expression in citrus fruits. Ecotoxicol Environ Saf 2022; 246:114153. [PMID: 36252515 DOI: 10.1016/j.ecoenv.2022.114153] [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] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Revised: 09/30/2022] [Accepted: 10/03/2022] [Indexed: 06/16/2023]
Abstract
Citric acid content is a critical quality determinant in citrus (Citrus spp.) fruits. Although arsenic (As) can effectively reduce citric acid content to improve citrus fruit quality, it can have adverse environmental effects. The discovery of nontoxic substitutes is hampered by the incomplete elucidation of the underlying mechanisms of As action in citrus fruits. Metabolic, transcriptomic, and physiological analyses were employed to investigate As action on citric acid accumulation to discover the mechanisms of As action in citrus. The enzyme activity related to citrate biosynthesis was not inhibited and the content of the involved metabolites was not reduced in As-treated fruits. However, the proton pump genes CitPH5 and CitPH1 control the vacuolar citric acid accumulation and transcription factor genes CitTT8 and CitMYB5, which regulate CitPH5 and CitPH1, were downregulated. The oxidative stress-response genes were upregulated in As-treated fruits. The reactive oxygen species (ROS) treatment also downregulated CitTT8 and CitMYB5 in juice cells. The mitochondrial ROS production rate increased in As-treated fruits. AsIII was more potent in stimulating isolated mitochondria to overproduce ROS compared to AsV. Our results indicate that the As inhibition of citric acid accumulation may be primarily due to the transcriptional downregulation of CitPH5, CitPH1, CitTT8, and CitMYB5. As-induced oxidative stress signaling may operate upstream to downregulate these acid regulator genes. Mitochondrial thiol proteins may be the principal targets of As action in citrus fruits.
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Affiliation(s)
- Diyang Qiu
- Institute of Fruit Tree Research, Guangdong Academy of Agricultural Sciences; Key Laboratory of South Subtropical Fruit Biology and Genetic Resource Utilization (MARA), Guangdong Province Key Laboratory of Tropical and Subtropical Fruit Tree Research, Guangzhou 510640, China.
| | - Congyi Zhu
- Institute of Fruit Tree Research, Guangdong Academy of Agricultural Sciences; Key Laboratory of South Subtropical Fruit Biology and Genetic Resource Utilization (MARA), Guangdong Province Key Laboratory of Tropical and Subtropical Fruit Tree Research, Guangzhou 510640, China.
| | - Ruiyi Fan
- Institute of Fruit Tree Research, Guangdong Academy of Agricultural Sciences; Key Laboratory of South Subtropical Fruit Biology and Genetic Resource Utilization (MARA), Guangdong Province Key Laboratory of Tropical and Subtropical Fruit Tree Research, Guangzhou 510640, China.
| | - Genlin Mao
- Institute of Fruit Tree Research, Guangdong Academy of Agricultural Sciences; Key Laboratory of South Subtropical Fruit Biology and Genetic Resource Utilization (MARA), Guangdong Province Key Laboratory of Tropical and Subtropical Fruit Tree Research, Guangzhou 510640, China.
| | - Pingzhi Wu
- Institute of Fruit Tree Research, Guangdong Academy of Agricultural Sciences; Key Laboratory of South Subtropical Fruit Biology and Genetic Resource Utilization (MARA), Guangdong Province Key Laboratory of Tropical and Subtropical Fruit Tree Research, Guangzhou 510640, China.
| | - Jiwu Zeng
- Institute of Fruit Tree Research, Guangdong Academy of Agricultural Sciences; Key Laboratory of South Subtropical Fruit Biology and Genetic Resource Utilization (MARA), Guangdong Province Key Laboratory of Tropical and Subtropical Fruit Tree Research, Guangzhou 510640, China.
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15
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Gao M, Sun Q, Zhai L, Zhao D, Lv J, Han Z, Wu T, Zhang X, Xu X, Wang Y. Genome-wide identification of apple PPI genes and a functional analysis of the response of MxPPI1 to Fe deficiency stress. Plant Physiol Biochem 2022; 189:94-103. [PMID: 36063740 DOI: 10.1016/j.plaphy.2022.08.017] [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] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 08/14/2022] [Accepted: 08/20/2022] [Indexed: 06/15/2023]
Abstract
Iron (Fe) deficiency affects plant growth and development. The proton pump interactor (PPI) in plants responds to multiple abiotic stresses, although it has not been well characterized under Fe deficiency stress. In this study, we systematically identified and analyzed the PPI gene family in apple. Three PPI candidate genes were found, and they contained 318-1349 amino acids and 3-7 introns. Under Fe deficiency stress, we analyzed the expression of all the PPI genes in roots of apple rootstock Malus xiaojinensis. Expression of the gene MD11G1247800, designated PPI1, is obviously induced by Fe deficiency treatment in M. xiaojinensis. We first cloned MxPPI1 from M. xiaojinensis and determined its subcellular localization, which indicated that it is localized in the cell membrane and nucleus in tobacco. We found that the level of expression of the MxPPI1 protein increased significantly under Fe deficiency stress in apple calli. Moreover, overexpressing MxPPI1 in apple calli enhanced the activities of ferric chelate reductase and H+-ATPase, H+ secretion, MxHA2 gene expression and total Fe content when compared with the wild type calli. We further found that MxPPI1 interacted with MxHA2 using bimolecular fluorescence complementation and luciferase complementation assays. Overall, we demonstrated that MxPPI1 interacts with MxHA2 to enhance the activity of H+-ATPase to regulate Fe absorption in M. xiaojinensis.
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Affiliation(s)
- Min Gao
- College of Horticulture, China Agricultural University, Beijing, 100193, PR China; Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (Nutrition and Physiology), Ministry of Agriculture and Rural Affairs, Beijing, 100193, PR China
| | - Qiran Sun
- College of Horticulture, China Agricultural University, Beijing, 100193, PR China; Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (Nutrition and Physiology), Ministry of Agriculture and Rural Affairs, Beijing, 100193, PR China
| | - Longmei Zhai
- College of Horticulture, China Agricultural University, Beijing, 100193, PR China; Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (Nutrition and Physiology), Ministry of Agriculture and Rural Affairs, Beijing, 100193, PR China
| | - Danrui Zhao
- College of Horticulture, China Agricultural University, Beijing, 100193, PR China; Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (Nutrition and Physiology), Ministry of Agriculture and Rural Affairs, Beijing, 100193, PR China
| | - Jiahong Lv
- College of Horticulture, China Agricultural University, Beijing, 100193, PR China; Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (Nutrition and Physiology), Ministry of Agriculture and Rural Affairs, Beijing, 100193, PR China
| | - Zhenhai Han
- College of Horticulture, China Agricultural University, Beijing, 100193, PR China; Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (Nutrition and Physiology), Ministry of Agriculture and Rural Affairs, Beijing, 100193, PR China
| | - Ting Wu
- College of Horticulture, China Agricultural University, Beijing, 100193, PR China; Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (Nutrition and Physiology), Ministry of Agriculture and Rural Affairs, Beijing, 100193, PR China
| | - Xinzhong Zhang
- College of Horticulture, China Agricultural University, Beijing, 100193, PR China; Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (Nutrition and Physiology), Ministry of Agriculture and Rural Affairs, Beijing, 100193, PR China
| | - Xuefeng Xu
- College of Horticulture, China Agricultural University, Beijing, 100193, PR China; Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (Nutrition and Physiology), Ministry of Agriculture and Rural Affairs, Beijing, 100193, PR China
| | - Yi Wang
- College of Horticulture, China Agricultural University, Beijing, 100193, PR China; Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (Nutrition and Physiology), Ministry of Agriculture and Rural Affairs, Beijing, 100193, PR China.
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16
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Zhou Z, Zheng S, Haq SIU, Zheng D, Qiu QS. Regulation of pollen tube growth by cellular pH and ions. J Plant Physiol 2022; 277:153792. [PMID: 35973258 DOI: 10.1016/j.jplph.2022.153792] [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] [Subscribe] [Scholar Register] [Received: 07/02/2022] [Revised: 07/29/2022] [Accepted: 08/06/2022] [Indexed: 06/15/2023]
Abstract
Tip growth of the pollen tube is a model system for the study of cell polarity establishment in flowering plants. The tip growth of the pollen tube displays an oscillating pattern corresponding to cellular ion and pH dynamics. Therefore, cellular pH and ions play an important role in pollen growth and development. In this review, we summarized the current advances in understanding the function of cellular pH and ions in regulating pollen tube growth. We analyzed the physiological roles and underlying mechanisms of cellular pH and ions, including Ca2+, K+, and Cl-, in regulating pollen tube growth. We further examined the function of Ca2+ in regulating cytoskeletons, small G proteins, and cell wall development in relation to pollen tube growth. We also examined the regulatory roles of cellular pH in pollen tube growth as well as pH regulation of ion flow, cell wall development, auxin signaling, and cytoskeleton function in pollen. In addition, we assessed the regulation of pollen tube growth by proton pumps and the maintenance of pH homeostasis in the trans-Golgi network by ion transporters. The interplay of ion homeostasis and pH dynamics was also assessed. We discussed the unanswered questions regarding pollen tube growth that need to be addressed in the future.
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Affiliation(s)
- Zhenguo Zhou
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, 73000, China.
| | - Sheng Zheng
- College of Life Sciences, Northwest Normal University, Lanzhou, Gansu, 730070, China; Academy of Plateau Science and Sustainability, Qinghai Normal University, Xining, Qinghai, 810016, China
| | - Syed Inzimam Ul Haq
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, 73000, China
| | - Dianfeng Zheng
- College of Coastal Agricultural Sciences, Guangdong Ocean University, Zhanjiang, Guangdong, 524088, China
| | - Quan-Sheng Qiu
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, 73000, China; Academy of Plateau Science and Sustainability, Qinghai Normal University, Xining, Qinghai, 810016, China; College of Coastal Agricultural Sciences, Guangdong Ocean University, Zhanjiang, Guangdong, 524088, China.
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17
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Petrovskaya LE, Lukashev EP, Siletsky SA, Imasheva ES, Wang JM, Mamedov MD, Kryukova EA, Dolgikh DA, Rubin AB, Kirpichnikov MP, Balashov SP, Lanyi JK. Proton transfer reactions in donor site mutants of ESR, a retinal protein from Exiguobacterium sibiricum. J Photochem Photobiol B 2022; 234:112529. [PMID: 35878544 DOI: 10.1016/j.jphotobiol.2022.112529] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 07/04/2022] [Accepted: 07/14/2022] [Indexed: 06/15/2023]
Abstract
Light-driven proton transport by microbial retinal proteins such as archaeal bacteriorhodopsin involves carboxylic residues as internal proton donors to the catalytic center which is a retinal Schiff base (SB). The proton donor, Asp96 in bacteriorhodopsin, supplies a proton to the transiently deprotonated Schiff base during the photochemical cycle. Subsequent proton uptake resets the protonated state of the donor. This two step process became a distinctive signature of retinal based proton pumps. Similar steps are observed also in many natural variants of bacterial proteorhodopsins and xanthorhodopsins where glutamic acid residues serve as a proton donor. Recently, however, an exception to this rule was found. A retinal protein from Exiguobacterium sibiricum, ESR, contains a Lys residue in place of Asp or Glu, which facilitates proton transfer from the bulk to the SB. Lys96 can be functionally replaced with the more common donor residues, Asp or Glu. Proton transfer to the SB in the mutants containing these replacements (K96E and K96D/A47T) is much faster than in the proteins lacking the proton donor (K96A and similar mutants), and in the case of K96D/A47T, comparable with that in the wild type, indicating that carboxylic residues can replace Lys96 as proton donors in ESR. We show here that there are important differences in the functioning of these residues in ESR from the way Asp96 functions in bacteriorhodopsin. Reprotonation of the SB and proton uptake from the bulk occur almost simultaneously during the M to N transition (as in the wild type ESR at neutral pH), whereas in bacteriorhodopsin these two steps are well separated in time and occur during the M to N and N to O transitions, respectively.
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Affiliation(s)
- Lada E Petrovskaya
- Shemyakin & Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ul. Miklukho-Maklaya, 16/10, Moscow 117997, Russia.
| | - Evgeniy P Lukashev
- M. V. Lomonosov Moscow State University, Department of Biology, Leninskie gory, 1, Moscow 119234, Russia
| | - Sergey A Siletsky
- Belozersky Institute of Physical-Chemical Biology, Lomonosov Moscow State University, 119991 Moscow, Russian Federation.
| | - Eleonora S Imasheva
- Department of Physiology and Biophysics, University of California, Irvine, CA 92697, USA
| | - Jennifer M Wang
- Department of Physiology and Biophysics, University of California, Irvine, CA 92697, USA
| | - Mahir D Mamedov
- Belozersky Institute of Physical-Chemical Biology, Lomonosov Moscow State University, 119991 Moscow, Russian Federation
| | - Elena A Kryukova
- Shemyakin & Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ul. Miklukho-Maklaya, 16/10, Moscow 117997, Russia; Emanuel Institute of Biochemical Physics, Kosygina str., 4, Moscow 119334, Russia
| | - Dmitriy A Dolgikh
- Shemyakin & Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ul. Miklukho-Maklaya, 16/10, Moscow 117997, Russia; M. V. Lomonosov Moscow State University, Department of Biology, Leninskie gory, 1, Moscow 119234, Russia; Emanuel Institute of Biochemical Physics, Kosygina str., 4, Moscow 119334, Russia
| | - Andrei B Rubin
- M. V. Lomonosov Moscow State University, Department of Biology, Leninskie gory, 1, Moscow 119234, Russia
| | - Mikhail P Kirpichnikov
- Shemyakin & Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ul. Miklukho-Maklaya, 16/10, Moscow 117997, Russia; M. V. Lomonosov Moscow State University, Department of Biology, Leninskie gory, 1, Moscow 119234, Russia
| | - Sergei P Balashov
- Department of Physiology and Biophysics, University of California, Irvine, CA 92697, USA.
| | - Janos K Lanyi
- Department of Physiology and Biophysics, University of California, Irvine, CA 92697, USA
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18
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Yu CH, Wu HY, Lin HS, Yang CS. A conserved Trp residue in HwBR contributes to its unique tolerance toward acidic environments. Biophys J 2022; 121:3136-3145. [PMID: 35808832 PMCID: PMC9463644 DOI: 10.1016/j.bpj.2022.07.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 06/10/2022] [Accepted: 07/06/2022] [Indexed: 11/20/2022] Open
Abstract
Bacteriorhodopsin (BR) is a light-driven outward proton pump found mainly in halophilic archaea. A BR from an archaeon Haloquadratum walsbyi (HwBR) was found to pump protons under more acidic conditions compared with most known BR proteins. The atomic structural study on HwBR unveiled that a pair of hydrogen bonds between the BC and FG loop in its periplasmic region may be a factor in such improved pumping capability. Here, we further investigated the retinal-binding pocket of HwBR and found that Trp94 contributes to the higher acid tolerance. Through single mutations in a BR from Halobacterium salinarum and HwBR, we examined the conserved tryptophan residues in the retinal-binding pocket. Among these residues of HwBR, mutagenesis at Trp94 facing the periplasmic region caused the most significant disruption to optical stability and proton-pumping capability under acidic conditions. The other tryptophan residues of HwBR exerted little impact on both maximum absorption wavelength and pH-dependent proton pumping. Our findings suggest that the residues from Trp94 to the hydrogen bonds at the BC loop confer both optical stability and functionality on the overall protein in low-pH environments.
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Affiliation(s)
- Cheng-Han Yu
- Department of Biochemical Science and Technology, College of Life Science, National Taiwan University, Taipei, Taiwan
| | - Hsiang-Yu Wu
- Department of Biochemical Science and Technology, College of Life Science, National Taiwan University, Taipei, Taiwan
| | - Hong-Syuan Lin
- Department of Biochemical Science and Technology, College of Life Science, National Taiwan University, Taipei, Taiwan
| | - Chii-Shen Yang
- Department of Biochemical Science and Technology, College of Life Science, National Taiwan University, Taipei, Taiwan.
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19
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Wang ZF, Xie ZM, Tan YL, Li JY, Wang FL, Pei D, Li Z, Guo Y, Gong Z, Wang Y. Receptor-like protein kinase BAK1 promotes K+ uptake by regulating H+-ATPase AHA2 under low potassium stress. Plant Physiol 2022; 189:2227-2243. [PMID: 35604103 PMCID: PMC9342980 DOI: 10.1093/plphys/kiac237] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 05/01/2022] [Indexed: 05/25/2023]
Abstract
Potassium (K+) is one of the essential macronutrients for plant growth and development. However, the available K+ concentration in soil is relatively low. Plant roots can perceive low K+ (LK) stress, then enhance high-affinity K+ uptake by activating H+-ATPases in root cells, but the mechanisms are still unclear. Here, we identified the receptor-like protein kinase Brassinosteroid Insensitive 1-Associated Receptor Kinase 1 (BAK1) that is involved in LK response by regulating the Arabidopsis (Arabidopsis thaliana) plasma membrane H+-ATPase isoform 2 (AHA2). The bak1 mutant showed leaf chlorosis phenotype and reduced K+ content under LK conditions, which was due to the decline of K+ uptake capacity. BAK1 could directly interact with the AHA2 C terminus and phosphorylate T858 and T881, by which the H+ pump activity of AHA2 was enhanced. The bak1 aha2 double mutant also displayed a leaf chlorosis phenotype that was similar to their single mutants. The constitutively activated form AHA2Δ98 and phosphorylation-mimic form AHA2T858D or AHA2T881D could complement the LK sensitive phenotypes of both aha2 and bak1 mutants. Together, our data demonstrate that BAK1 phosphorylates AHA2 and enhances its activity, which subsequently promotes K+ uptake under LK conditions.
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Affiliation(s)
- Zhi-Fang Wang
- State Key Laboratory of Plant Physiology and Biochemistry (SKLPPB), College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Zhong-Mei Xie
- State Key Laboratory of Plant Physiology and Biochemistry (SKLPPB), College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Ya-Lan Tan
- State Key Laboratory of Plant Physiology and Biochemistry (SKLPPB), College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Jia-Ying Li
- State Key Laboratory of Plant Physiology and Biochemistry (SKLPPB), College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Feng-Liu Wang
- State Key Laboratory of Plant Physiology and Biochemistry (SKLPPB), College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Dan Pei
- State Key Laboratory of Plant Physiology and Biochemistry (SKLPPB), College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Zhen Li
- State Key Laboratory of Plant Physiology and Biochemistry (SKLPPB), College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Yan Guo
- State Key Laboratory of Plant Physiology and Biochemistry (SKLPPB), College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Zhizhong Gong
- State Key Laboratory of Plant Physiology and Biochemistry (SKLPPB), College of Biological Sciences, China Agricultural University, Beijing 100193, China
- School of Life Sciences, Institute of Life Science and Green Development, Hebei University, Baoding, Hebei 071002, China
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20
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Abstract
The first microbial rhodopsin, a light-driven proton pump bacteriorhodopsin from Halobacterium salinarum (HsBR), was discovered in 1971. Since then, this seven-α-helical protein, comprising a retinal molecule as a cofactor, became a major driver of groundbreaking developments in membrane protein research. However, until 1999 only a few archaeal rhodopsins, acting as light-driven proton and chloride pumps and also photosensors, were known. A new microbial rhodopsin era started in 2000 when the first bacterial rhodopsin, a proton pump, was discovered. Later it became clear that there are unexpectedly many rhodopsins, and they are present in all the domains of life and even in viruses. It turned out that they execute such a diversity of functions while being "nearly the same." The incredible evolution of the research area of rhodopsins and the scientific and technological potential of the proteins is described in the review with a focus on their function-structure relationships.
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Affiliation(s)
- Valentin Gordeliy
- Institut de Biologie Structurale (IBS), Université Grenoble Alpes, CEA, CNRS, Grenoble, France.
| | - Kirill Kovalev
- Institut de Biologie Structurale (IBS), Université Grenoble Alpes, CEA, CNRS, Grenoble, France
- Institute of Biological Information Processing (IBI-7: Structural Biochemistry), Forschungszentrum Jülich GmbH, Jülich, Germany
- JuStruct: Jülich Center for Structural Biology, Forschungszentrum Jülich GmbH, Jülich, Germany
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology (National Research University), Dolgoprudny, Russia
- Institute of Crystallography, University of Aachen (RWTH), Aachen, Germany
| | - Ernst Bamberg
- Max Planck Institute of Biophysics, Frankfurt am Main, Germany
| | - Francisco Rodriguez-Valera
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology (National Research University), Dolgoprudny, Russia
- Evolutionary Genomics Group, Departamento de Producción Vegetal y Microbiología, Universidad Miguel Hernández, San Juan de Alicante, Alicante, Spain
| | - Egor Zinovev
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology (National Research University), Dolgoprudny, Russia
| | - Dmitrii Zabelskii
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology (National Research University), Dolgoprudny, Russia
| | - Alexey Alekseev
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology (National Research University), Dolgoprudny, Russia
| | - Riccardo Rosselli
- Departamento de Fisiología, Genetica y Microbiología. Facultad de Ciencias, Universidad de Alicante, Alicante, Spain
| | - Ivan Gushchin
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology (National Research University), Dolgoprudny, Russia
| | - Ivan Okhrimenko
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology (National Research University), Dolgoprudny, Russia
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Choi HI, Hwang SW, Kim J, Park B, Jin E, Choi IG, Sim SJ. Augmented CO 2 tolerance by expressing a single H +-pump enables microalgal valorization of industrial flue gas. Nat Commun 2021; 12:6049. [PMID: 34663809 PMCID: PMC8523702 DOI: 10.1038/s41467-021-26325-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [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: 03/23/2021] [Accepted: 10/01/2021] [Indexed: 12/02/2022] Open
Abstract
Microalgae can accumulate various carbon-neutral products, but their real-world applications are hindered by their CO2 susceptibility. Herein, the transcriptomic changes in a model microalga, Chlamydomonas reinhardtii, in a high-CO2 milieu (20%) are evaluated. The primary toxicity mechanism consists of aberrantly low expression of plasma membrane H+-ATPases (PMAs) accompanied by intracellular acidification. Our results demonstrate that the expression of a universally expressible PMA in wild-type strains makes them capable of not only thriving in acidity levels that they usually cannot survive but also exhibiting 3.2-fold increased photoautotrophic production against high CO2 via maintenance of a higher cytoplasmic pH. A proof-of-concept experiment involving cultivation with toxic flue gas (13 vol% CO2, 20 ppm NOX, and 32 ppm SOX) shows that the production of CO2-based bioproducts by the strain is doubled compared with that by the wild-type, implying that this strategy potentially enables the microalgal valorization of CO2 in industrial exhaust.
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Affiliation(s)
- Hong Il Choi
- Department of Chemical and Biological Engineering, Korea University, 145, Anam-ro, Seongbuk-gu, Seoul, 02841, Republic of Korea
| | - Sung-Won Hwang
- Department of Chemical and Biological Engineering, Korea University, 145, Anam-ro, Seongbuk-gu, Seoul, 02841, Republic of Korea
| | - Jongrae Kim
- Department of Life Science, Hanyang University, 206, Wangsimni-ro, Seongbuk-gu, Seoul, 04763, Republic of Korea
| | - Byeonghyeok Park
- Department of Biotechnology, Korea University, 145, Anam-ro, Seongbuk-gu, Seoul, 02841, Republic of Korea
| | - EonSeon Jin
- Department of Life Science, Hanyang University, 206, Wangsimni-ro, Seongbuk-gu, Seoul, 04763, Republic of Korea
| | - In-Geol Choi
- Department of Biotechnology, Korea University, 145, Anam-ro, Seongbuk-gu, Seoul, 02841, Republic of Korea
| | - Sang Jun Sim
- Department of Chemical and Biological Engineering, Korea University, 145, Anam-ro, Seongbuk-gu, Seoul, 02841, Republic of Korea.
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22
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Siletsky SA, Borisov VB. Proton Pumping and Non-Pumping Terminal Respiratory Oxidases: Active Sites Intermediates of These Molecular Machines and Their Derivatives. Int J Mol Sci 2021; 22:10852. [PMID: 34639193 PMCID: PMC8509429 DOI: 10.3390/ijms221910852] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [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: 08/31/2021] [Revised: 10/04/2021] [Accepted: 10/05/2021] [Indexed: 11/16/2022] Open
Abstract
Terminal respiratory oxidases are highly efficient molecular machines. These most important bioenergetic membrane enzymes transform the energy of chemical bonds released during the transfer of electrons along the respiratory chains of eukaryotes and prokaryotes from cytochromes or quinols to molecular oxygen into a transmembrane proton gradient. They participate in regulatory cascades and physiological anti-stress reactions in multicellular organisms. They also allow microorganisms to adapt to low-oxygen conditions, survive in chemically aggressive environments and acquire antibiotic resistance. To date, three-dimensional structures with atomic resolution of members of all major groups of terminal respiratory oxidases, heme-copper oxidases, and bd-type cytochromes, have been obtained. These groups of enzymes have different origins and a wide range of functional significance in cells. At the same time, all of them are united by a catalytic reaction of four-electron reduction in oxygen into water which proceeds without the formation and release of potentially dangerous ROS from active sites. The review analyzes recent structural and functional studies of oxygen reduction intermediates in the active sites of terminal respiratory oxidases, the features of catalytic cycles, and the properties of the active sites of these enzymes.
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Affiliation(s)
- Sergey A. Siletsky
- Department of Bioenergetics, Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskie Gory, Moscow 119991, Russia
| | - Vitaliy B. Borisov
- Department of Molecular Energetics of Microorganisms, Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskie Gory, Moscow 119991, Russia;
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Ekom SE, Tamokou JDD, Kuete V. Antibacterial and Therapeutic Potentials of the Capsicum annuum Extract against Infected Wound in a Rat Model with Its Mechanisms of Antibacterial Action. Biomed Res Int 2021; 2021:4303902. [PMID: 34646883 PMCID: PMC8505066 DOI: 10.1155/2021/4303902] [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] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 08/31/2021] [Accepted: 09/03/2021] [Indexed: 11/21/2022]
Abstract
The wound healing process is essential to reform the damaged tissue and prevent its invasion by pathogens. The present study aims at evaluating the antibacterial and therapeutic properties of the Capsicum annuum L. (Solanaceae) extract against infected wound in a rat model with its mechanisms of antibacterial action. The fruit extract was prepared by maceration in methanol. The broth microdilution method was used to investigate the antibacterial activity of the methanol extract of C. annuum fruits. The therapeutic effect of the extract gel was performed on an excision wound infected with Staphylococcus aureus using a rat model. The total phenol, flavonoid, and tannin contents as well as the antibacterial mechanisms of action of the extract were determined using spectrophotometric methods. The C. annuum fruit extract showed antibacterial properties which can be linked to its total phenolic, flavonoid, and tannin contents. The antibacterial activity is due to the inhibition of the biofilm formation, ATPases/H+ proton pump, and dehydrogenase activity as well as the alteration of the bacterial cell membrane through the leakage of nucleic acids, reducing sugars and proteins. The extract gel showed a significant (p < 0.05) increase in the percentage of wound closure and eradicated S. aureus at the infection site. The extract gel was nonirritating to the skin and slightly irritating to the eyes and should be used with caution. Overall, the findings of the present study support the traditional use of the studied plant in the treatment of wounds and infectious diseases associated with the tested bacteria.
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Affiliation(s)
- Steve Endeguele Ekom
- Research Unit of Microbiology and Antimicrobial Substances, Department of Biochemistry, University of Dschang, P.O. Box 67, Dschang, Cameroon
| | - Jean-De-Dieu Tamokou
- Research Unit of Microbiology and Antimicrobial Substances, Department of Biochemistry, University of Dschang, P.O. Box 67, Dschang, Cameroon
| | - Victor Kuete
- Research Unit of Microbiology and Antimicrobial Substances, Department of Biochemistry, University of Dschang, P.O. Box 67, Dschang, Cameroon
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Sachkova A, Doetsch DA, Jensen O, Brockmöller J, Ansari S. How do psychostimulants enter the human brain? Analysis of the role of the proton-organic cation antiporter. Biochem Pharmacol 2021; 192:114751. [PMID: 34464621 DOI: 10.1016/j.bcp.2021.114751] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 08/26/2021] [Accepted: 08/26/2021] [Indexed: 11/17/2022]
Abstract
BACKGROUND Although psychostimulants apparently do cross the BBB, it is poorly understood how these hydrophilic and positively charged molecules can pass the blood-brain barrier (BBB). That may be mediated by a genetically still uncharacterized H+/OC antiporter with high activity at the BBB. METHODS We studied the uptake of 16 psychostimulants and hallucinogens with hCMEC/D3 cells using the prototypic inhibitor imipramine (cis-inhibition), exchange transport with diphenhydramine and clonidine (trans-stimulation), proton dependency of the uptake, and we characterized the concentration-dependent uptake. RESULTS Cell uptake of methylenedioxyamphetamines, amphetamines and dimethyltryptamine (DMT) were strongly inhibited (to about 10% of the controls) by imipramine and diphenhydramine, whereas uptake of cathine was only weakly inhibited and mescaline not significantly. Amphetamine, methylamphetamine, para-Methoxy-N-methylamphetamine (PMMA), Methylenedioxymethamphetamine (MDMA), phentermine and DMT exhibited the highest exchange after preloading with diphenhydramine with only 5.5%, 5.2%, 7.8%, 6%, 1.9%, 7.6% remaining in the cells. Less and no exchange were seen with cathine and mescaline, respectively. Dependence on intracellular pH was most pronounced with the methylendioxyamphetamines while uptake of cathine, DOI and cocaine were only moderately affected and mescaline not at all. CONCLUSION Except for mescaline, all psychostimulants studied here were substrates of the H+/OC antiporter, implicating a strong need for a better characterization of this transport protein.
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Affiliation(s)
- Alexandra Sachkova
- Institute of Clinical Pharmacology, University Medical Center Göttingen, Georg-August University, D-37075 Göttingen, Germany; Department of Anesthesiology and Intensive Care Medicine, University Medical Center Göttingen, Germany.
| | - David Alexander Doetsch
- Institute of Clinical Pharmacology, University Medical Center Göttingen, Georg-August University, D-37075 Göttingen, Germany
| | - Ole Jensen
- Institute of Clinical Pharmacology, University Medical Center Göttingen, Georg-August University, D-37075 Göttingen, Germany
| | - Jürgen Brockmöller
- Institute of Clinical Pharmacology, University Medical Center Göttingen, Georg-August University, D-37075 Göttingen, Germany
| | - Salim Ansari
- Institute of Clinical Pharmacology, University Medical Center Göttingen, Georg-August University, D-37075 Göttingen, Germany
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Olaniyan OT, Ojewale AO, Eweoya OO, Adedoyin AA, Adesanya OA, Adeoye AO, Okeniran OS. Modulatory Role of Vitamin E on Proton Pump (ATPase) Activity of Cadmium Chloride-Induced Testicular Damage in Wistar Rats. Biomed Res Int 2021; 2021:4615384. [PMID: 33604374 PMCID: PMC7870308 DOI: 10.1155/2021/4615384] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 01/13/2021] [Accepted: 01/22/2021] [Indexed: 11/18/2022]
Abstract
Proton pumps are membrane-bound enzymes important in generating gradients that help in maintaining cellular ion homeostasis, cell membrane potential, water, and solute transport across the cell surface. This study investigated the modulatory role of vitamin E on proton pump activity and reproductive parameters in cadmium-induced testicular damage. Twenty (20) male Wistar rats weighing between 180 and 200 g were sorted into 4 groups of five rats each. Group I served as the control and was given normal saline orally, Group II rats were treated with a single dose of 2 mg/kg BW cadmium chloride (CdCl2) intraperitoneally, Group III rats were given 100 mg/kg BW of vitamin E orally, and Group IV rats were given 100 mg/kg BW of vitamin E orally for 30 days prior to intraperitoneal administration of single dose of 2 mg/kg BW of cadmium chloride. The rats were anaesthetized with diethyl ether, and blood samples were obtained for sex hormonal analysis; caudal epididymis was dissected for sperm count, motility, and viability, and the testis were homogenized for lipid peroxidation and proton pump (Na+/K+ ATPase, Ca2+ ATPase, and Mg2+ ATPase) activity. Proton pump activity was assayed spectrophotometrically using the Stewart method to determine the inorganic phosphate level. Histopathological changes of the testis were also studied. The group treated with CdCl2 showed a significant (p < 0.05) decrease in proton pump activity, sperm count, and motility and a significant (p < 0.05) increase in malondialdehyde level when compared with the control group. The CdCl2-treated group also showed decrease reproductive organ weights and hormonal levels and cause necrosis of spermatogonia lining the seminiferous tubules. Rats treated with vitamin E orally for 30 days prior to CdCl2 exposure showed improvement in proton pump activity, a significant (p < 0.05) increase in sperm parameters and luteinizing hormonal level, and a decrease in the lipid peroxidation level as compared with the CdCl2 group. This study showed that vitamin E ameliorated the toxic effect of CdCl2 on proton pump activity in the testes, hence improving testicular integrity, structures, and functions.
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Affiliation(s)
- Olugbemi T. Olaniyan
- Laboratory for Reproductive Physiology and Developmental Programming, Department of Physiology, Edo University Iyamho, Edo State, Nigeria
| | | | - Olugbenga O. Eweoya
- Department of Anatomy, College of Health Sciences, University of Abuja, Abuja, Nigeria
- Department of Anatomy, School of Medicine, University of Gambia, Banjul, Gambia
| | | | | | - Azeez O. Adeoye
- Department of Anatomy, Kampala International University, Bushenyi, Uganda
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26
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Conrad KP. Might proton pump or sodium-hydrogen exchanger inhibitors be of value to ameliorate SARs-CoV-2 pathophysiology? Physiol Rep 2021; 8:e14649. [PMID: 33369281 PMCID: PMC7762781 DOI: 10.14814/phy2.14649] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [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: 08/01/2020] [Revised: 09/17/2020] [Accepted: 09/18/2020] [Indexed: 12/26/2022] Open
Abstract
Discovering therapeutics for COVID-19 is a priority. Besides high-throughput screening of compounds, candidates might be identified based on their known mechanisms of action and current understanding of the SARs-CoV-2 life cycle. Using this approach, proton pump (PPIs) and sodium-hydrogen exchanger inhibitors (NHEIs) emerged, because of their potential to inhibit the release of extracellular vesicles (EVs; exosomes and/or microvesicles) that could promote disease progression, and to directly disrupt SARs-CoV-2 pathogenesis. If EVs exacerbate SARs-CoV-2 infection as suggested for other viruses, then inhibiting EV release by PPIs/NHEIs should be beneficial. Mechanisms underlying inhibition of EV release by these drugs remain uncertain, but may involve perturbing endosomal pH especially of multivesicular bodies where intraluminal vesicles (nascent exosomes) are formed. Additionally, PPIs might inhibit the endosomal sorting complex for transport machinery involved in EV biogenesis. Through perturbing endocytic vesicle pH, PPIs/NHEIs could also impede cleavage of SARs-CoV-2 spike protein by cathepsins necessary for viral fusion with the endosomal membrane. Although pulmonary epithelial cells may rely mainly on plasma membrane serine protease TMPRSS2 for cell entry, PPIs/NHEIs might be efficacious in ACE2-expressing cells where viral endocytosis is the major or a contributing entry pathway. These pharmaceutics might also perturb pH in the endoplasmic reticulum-Golgi intermediate and Golgi compartments, thereby potentially disrupting viral assembly and glycosylation of spike protein/ACE2, respectively. A caveat, however, is that facilitation not inhibition of avian infectious bronchitis CoV pathogenesis was reported in one study after increasing Golgi pH. Envelope protein-derived viroporins contributed to pulmonary edema formation in mice infected with SARs-CoV. If similar pathogenesis occurs with SARs-CoV-2, then blocking these channels with NHEIs could ameliorate disease pathogenesis. To ascertain their potential efficacy, PPIs/NHEIs need evaluation in cell and animal models at various phases of SARs-CoV-2 infection. If they prove to be therapeutic, the greatest benefit might be realized with the administration before the onset of severe cytokine release syndrome.
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Affiliation(s)
- Kirk P. Conrad
- Departments of Physiology and Functional Genomics, and of Obstetrics and GynecologyUniversity of Florida College of MedicineGainesvilleFLUSA
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Wang Y, Ying J, Zhang Y, Xu L, Zhang W, Ni M, Zhu Y, Liu L. Genome-Wide Identification and Functional Characterization of the Cation Proton Antiporter (CPA) Family Related to Salt Stress Response in Radish ( Raphanus sativus L.). Int J Mol Sci 2020; 21:E8262. [PMID: 33158201 PMCID: PMC7662821 DOI: 10.3390/ijms21218262] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [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: 10/01/2020] [Revised: 10/29/2020] [Accepted: 11/02/2020] [Indexed: 01/04/2023] Open
Abstract
The CPA (cation proton antiporter) family plays an essential role during plant stress tolerance by regulating ionic and pH homeostasis of the cell. Radish fleshy roots are susceptible to abiotic stress during growth and development, especially salt stress. To date, CPA family genes have not yet been identified in radish and the biological functions remain unclear. In this study, 60 CPA candidate genes in radish were identified on the whole genome level, which were divided into three subfamilies including the Na+/H+ exchanger (NHX), K+ efflux antiporter (KEA), and cation/H+ exchanger (CHX) families. In total, 58 of the 60 RsCPA genes were localized to the nine chromosomes. RNA-seq. data showed that 60 RsCPA genes had various expression levels in the leaves, roots, cortex, cambium, and xylem at different development stages, as well as under different abiotic stresses. RT-qPCR analysis indicated that all nine RsNHXs genes showed up regulated trends after 250 mM NaCl exposure at 3, 6, 12, and 24h. The RsCPA31 (RsNHX1) gene, which might be the most important members of the RsNHX subfamily, exhibited obvious increased expression levels during 24h salt stress treatment. Heterologous over-and inhibited-expression of RsNHX1 in Arabidopsis showed that RsNHX1 had a positive function in salt tolerance. Furthermore, a turnip yellow mosaic virus (TYMV)-induced gene silence (VIGS) system was firstly used to functionally characterize the candidate gene in radish, which showed that plant with the silence of endogenous RsNHX1 was more susceptible to the salt stress. According to our results we provide insights into the complexity of the RsCPA gene family and a valuable resource to explore the potential functions of RsCPA genes in radish.
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Affiliation(s)
| | | | | | | | | | | | - Yuelin Zhu
- National Key Laboratory of Crop Genetics and Germplasm Enhancement, Key Laboratory of Horticultural Crop Biology and Genetic Improvement (East China) of MOAR, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China; (Y.W.); (J.Y.); (Y.Z.); (L.X.); (W.Z.); (M.N.)
| | - Liwang Liu
- National Key Laboratory of Crop Genetics and Germplasm Enhancement, Key Laboratory of Horticultural Crop Biology and Genetic Improvement (East China) of MOAR, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China; (Y.W.); (J.Y.); (Y.Z.); (L.X.); (W.Z.); (M.N.)
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28
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Harguindey S, Alfarouk K, Polo Orozco J, Fais S, Devesa J. Towards an Integral Therapeutic Protocol for Breast Cancer Based upon the New H +-Centered Anticancer Paradigm of the Late Post-Warburg Era. Int J Mol Sci 2020; 21:E7475. [PMID: 33050492 PMCID: PMC7589677 DOI: 10.3390/ijms21207475] [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] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 10/05/2020] [Accepted: 10/06/2020] [Indexed: 12/13/2022] Open
Abstract
A brand new approach to the understanding of breast cancer (BC) is urgently needed. In this contribution, the etiology, pathogenesis, and treatment of this disease is approached from the new pH-centric anticancer paradigm. Only this unitarian perspective, based upon the hydrogen ion (H+) dynamics of cancer, allows for the understanding and integration of the many dualisms, confusions, and paradoxes of the disease. The new H+-related, wide-ranging model can embrace, from a unique perspective, the many aspects of the disease and, at the same time, therapeutically interfere with most, if not all, of the hallmarks of cancer known to date. The pH-related armamentarium available for the treatment of BC reviewed here may be beneficial for all types and stages of the disease. In this vein, we have attempted a megasynthesis of traditional and new knowledge in the different areas of breast cancer research and treatment based upon the wide-ranging approach afforded by the hydrogen ion dynamics of cancer. The concerted utilization of the pH-related drugs that are available nowadays for the treatment of breast cancer is advanced.
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Affiliation(s)
- Salvador Harguindey
- Department of Oncology, Institute of Clinical Biology and Metabolism, 01004 Vitoria, Spain;
| | - Khalid Alfarouk
- Department of Pharmacology, Al-Ghad International Colleges for Applied Medical Sciences, Al-Madinah Al-Munawarah 42316, Saudi Arabia and Alfarouk Biomedical Research LLC, Tampa, FL 33617, USA;
| | - Julián Polo Orozco
- Department of Oncology, Institute of Clinical Biology and Metabolism, 01004 Vitoria, Spain;
| | - Stefano Fais
- Department of Oncology and Molecular Medicine, Istituto Superiore di Sanità (National Institute of Health), 00161 Rome, Italy;
| | - Jesús Devesa
- Scientific Direction, Foltra Medical Centre, 15886 Teo, Spain;
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29
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Camilo SMP, Almeida ÉCDS, Sousa JB, Camilo LP, Etchebehere RM. CHRONIC USE OF PROTON PUMP INHIBITORS AND THE QUANTITY OF G, D, AND ECL CELLS IN THE STOMACH. Arq Bras Cir Dig 2020; 33:e1506. [PMID: 32844883 PMCID: PMC7448853 DOI: 10.1590/0102-672020190001e1506] [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] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 04/02/2020] [Indexed: 11/22/2022]
Abstract
BACKGROUND Acid inhibition from chronic proton pump inhibitor use and a possible increase in gastrin can lead to changes in the regulation of hydrochloric acid production. However, it has not known whether such chronic use changes the presence of gastrin, delta, and enterochromaffin-like cells in the stomach or the relationship between gastrin and delta cells. AIM To analyze the number of gastrin-producing gastrin cells, somatostatin-producing cells, and histamine-producing cells in patients who were chronic users of proton pump inhibitor, with or without related Helicobacter pylori infection. METHODS Biopsies from 105 patients, including 81 chronic proton pump inhibitor users (experimental group) and 24 controls, were processed immunohistochemically and subjected to counting of gastrin, delta, and enterochromaffin-like cells in high-magnification microscopic fields and in 10 glands. RESULTS Gastrin cell, delta cell, and enterochromaffin-like cells counts were similar across the groups and appeared to be unaffected by Helicobacter pylori infection. The ratio between gastrin cells and delta cells was higher in the chronic users of proton pump inhibitor group than in controls. CONCLUSION Chronic users of proton pump inhibitor does not affect gastrin cell, delta cell, and enterochromaffin-like cell counts significantly, but may alter the ratio between gastrin cells and delta cells.
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Affiliation(s)
- Silvia Maria Perrone Camilo
- Post-Graduate Program in Health Sciences, Clinical Hospital, Triângulo Mineiro Federal University, Uberaba, MG, Brazil
| | - Élia Cláudia de Souza Almeida
- Post-Graduate Program in Health Sciences, Clinical Hospital, Triângulo Mineiro Federal University, Uberaba, MG, Brazil
| | - Jacqueline Batista Sousa
- Post-Graduate Program in Health Sciences, Triângulo Mineiro Federal University, Uberaba, MG, Brazil
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30
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Inoue K, Tsunoda SP, Singh M, Tomida S, Hososhima S, Konno M, Nakamura R, Watanabe H, Bulzu PA, Banciu HL, Andrei AŞ, Uchihashi T, Ghai R, Béjà O, Kandori H. Schizorhodopsins: A family of rhodopsins from Asgard archaea that function as light-driven inward H + pumps. Sci Adv 2020; 6:eaaz2441. [PMID: 32300653 PMCID: PMC7148096 DOI: 10.1126/sciadv.aaz2441] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 01/17/2020] [Indexed: 05/05/2023]
Abstract
Schizorhodopsins (SzRs), a rhodopsin family first identified in Asgard archaea, the archaeal group closest to eukaryotes, are present at a phylogenetically intermediate position between typical microbial rhodopsins and heliorhodopsins. However, the biological function and molecular properties of SzRs have not been reported. Here, SzRs from Asgardarchaeota and from a yet unknown microorganism are expressed in Escherichia coli and mammalian cells, and ion transport assays and patch clamp analyses are used to demonstrate SzR as a novel type of light-driven inward H+ pump. The mutation of a cytoplasmic glutamate inhibited inward H+ transport, suggesting that it functions as a cytoplasmic H+ acceptor. The function, trimeric structure, and H+ transport mechanism of SzR are similar to that of xenorhodopsin (XeR), a light-driven inward H+ pumping microbial rhodopsins, implying that they evolved convergently. The inward H+ pump function of SzR provides new insight into the photobiological life cycle of the Asgardarchaeota.
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Affiliation(s)
- Keiichi Inoue
- The Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan
- OptoBioTechnology Research Center, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan
- PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
- Corresponding author. (K.I.); (H.K.)
| | - Satoshi P. Tsunoda
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan
- OptoBioTechnology Research Center, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan
- PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
| | - Manish Singh
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan
| | - Sahoko Tomida
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan
| | - Shoko Hososhima
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan
| | - Masae Konno
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan
| | - Ryoko Nakamura
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan
| | - Hiroki Watanabe
- Exploratory Research Center on Life and Living Systems, Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan
- Department of Physics, Nagoya University, Nagoya 464-8602, Japan
| | - Paul-Adrian Bulzu
- Department of Molecular Biology and Biotechnology, Faculty of Biology and Geology, Babeş-Bolyai University, Cluj-Napoca, Romania
| | - Horia L. Banciu
- Department of Molecular Biology and Biotechnology, Faculty of Biology and Geology, Babeş-Bolyai University, Cluj-Napoca, Romania
| | - Adrian-Ştefan Andrei
- Department of Aquatic Microbial Ecology, Institute of Hydrobiology, Biology Centre of the Academy of Sciences of the Czech Republic, České Budějovice, Czech Republic
| | - Takayuki Uchihashi
- Exploratory Research Center on Life and Living Systems, Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan
- Department of Physics, Nagoya University, Nagoya 464-8602, Japan
| | - Rohit Ghai
- Department of Aquatic Microbial Ecology, Institute of Hydrobiology, Biology Centre of the Academy of Sciences of the Czech Republic, České Budějovice, Czech Republic
| | - Oded Béjà
- Faculty of Biology, Technion-Israel Institute of Technology, Haifa, Israel
| | - Hideki Kandori
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan
- OptoBioTechnology Research Center, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan
- Corresponding author. (K.I.); (H.K.)
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Harguindey S, Alfarouk K, Polo Orozco J, Hardonnière K, Stanciu D, Fais S, Devesa J. A New and Integral Approach to the Etiopathogenesis and Treatment of Breast Cancer Based upon Its Hydrogen Ion Dynamics. Int J Mol Sci 2020; 21:E1110. [PMID: 32046158 PMCID: PMC7036897 DOI: 10.3390/ijms21031110] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [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: 01/21/2020] [Revised: 02/04/2020] [Accepted: 02/06/2020] [Indexed: 12/11/2022] Open
Abstract
Despite all efforts, the treatment of breast cancer (BC) cannot be considered to be a success story. The advances in surgery, chemotherapy and radiotherapy have not been sufficient at all. Indeed, the accumulated experience clearly indicates that new perspectives and non-main stream approaches are needed to better characterize the etiopathogenesis and treatment of this disease. This contribution deals with how the new pH-centric anticancer paradigm plays a fundamental role in reaching a more integral understanding of the etiology, pathogenesis, and treatment of this multifactorial disease. For the first time, the armamentarium available for the treatment of the different types and phases of BC is approached here from a Unitarian perspective-based upon the hydrogen ion dynamics of cancer. The wide-ranged pH-related molecular, biochemical and metabolic model is able to embrace most of the fields and subfields of breast cancer etiopathogenesis and treatment. This single and integrated approach allows advancing towards a unidirectional, concerted and synergistic program of treatment. Further efforts in this line are likely to first improve the therapeutics of each subtype of this tumor and every individual patient in every phase of the disease.
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Affiliation(s)
- Salvador Harguindey
- Institute of Clinical Biology and Metabolism, Postas 13, 01004 Vitoria, Spain;
| | - Khalid Alfarouk
- Al-Ghad International Colleges for Applied Medical Sciences, Al-Madinah Al-Munawarah, Saudi Arabia and Alfarouk Biomedical Research LLC, Tampa, FL 33617, USA;
| | - Julián Polo Orozco
- Institute of Clinical Biology and Metabolism, Postas 13, 01004 Vitoria, Spain;
| | - Kévin Hardonnière
- Université Paris-Saclay, Inserm, Inflammation, Microbiome and Immunosurveillance, 92290 Châtenay-Malabry, France;
| | - Daniel Stanciu
- Scientific Direction, MCS Foundation For Life, 5623KR Eindhoven, The Netherlands;
| | - Stefano Fais
- Department of Oncology and Molecular Medicine, Istituto Superiore di Sanità (National Institute of Health), Viale Regina Elena, 299, 00161 Rome, Italy;
| | - Jesús Devesa
- Scientific Direction, Foltra Medical Centre, Travesía de Montouto 24, 15886 Teo, Spain;
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32
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Shabala S, Chen G, Chen ZH, Pottosin I. The energy cost of the tonoplast futile sodium leak. New Phytol 2020; 225:1105-1110. [PMID: 30802968 DOI: 10.1111/nph.15758] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2018] [Accepted: 02/10/2019] [Indexed: 05/18/2023]
Abstract
Active removal of Na+ from the cytosol into the vacuole plays a critical role in salinity tissue tolerance, but another, often neglected component of this trait is Na+ retention in vacuoles. This retention is based on an efficient control of Na+ -permeable slow- and fast-vacuolar channels that mediate the back-leak of Na+ into cytosol and, if not regulated tightly, could result in a futile cycle. This Tansley insight summarizes our current knowledge of regulation of tonoplast Na+ -permeable channels and discusses the energy cost of vacuolar Na+ sequestration, under different scenarios. We also report on a phylogenetic and bioinformatic analysis of the plant two-pore channel family and the difference in its structure and regulation between halophytes and glycophytes, in the context of salinity tolerance.
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Affiliation(s)
- Sergey Shabala
- International Centre for Environmental Membrane Biology, Foshan University, Foshan, 528041, China
- Tasmanian Institute for Agriculture, College of Science and Engineering, University of Tasmania, Hobart, Tas, 7005, Australia
| | - Guang Chen
- Department of Biology, University of Florida, Gainesville, FL, 32611, USA
| | - Zhong-Hua Chen
- School of Science and Health, Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, 2751, Australia
| | - Igor Pottosin
- Centro Universitario de Investigaciones Biomédicas, Universidad de Colima, Colima, 28045, México
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Schuller JM, Saura P, Thiemann J, Schuller SK, Gamiz-Hernandez AP, Kurisu G, Nowaczyk MM, Kaila VRI. Redox-coupled proton pumping drives carbon concentration in the photosynthetic complex I. Nat Commun 2020; 11:494. [PMID: 31980611 PMCID: PMC6981117 DOI: 10.1038/s41467-020-14347-4] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [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: 10/13/2019] [Accepted: 12/22/2019] [Indexed: 11/25/2022] Open
Abstract
Photosynthetic organisms capture light energy to drive their energy metabolism, and employ the chemical reducing power to convert carbon dioxide (CO2) into organic molecules. Photorespiration, however, significantly reduces the photosynthetic yields. To survive under low CO2 concentrations, cyanobacteria evolved unique carbon-concentration mechanisms that enhance the efficiency of photosynthetic CO2 fixation, for which the molecular principles have remained unknown. We show here how modular adaptations enabled the cyanobacterial photosynthetic complex I to concentrate CO2 using a redox-driven proton-pumping machinery. Our cryo-electron microscopy structure at 3.2 Å resolution shows a catalytic carbonic anhydrase module that harbours a Zn2+ active site, with connectivity to proton-pumping subunits that are activated by electron transfer from photosystem I. Our findings illustrate molecular principles in the photosynthetic complex I machinery that enabled cyanobacteria to survive in drastically changing CO2 conditions.
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Affiliation(s)
- Jan M Schuller
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, 82152, Martinsried, Germany.
| | - Patricia Saura
- Department of Biochemistry and Biophysics, Stockholm University, SE-106 91, Stockholm, Sweden
- Center of Integrated Protein Science at the Department of Chemistry, Technical University of Munich, Garching, Germany
| | - Jacqueline Thiemann
- Plant Biochemistry, Faculty of Biology and Biotechnology, Ruhr University Bochum, 44780, Bochum, Germany
| | - Sandra K Schuller
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, 82152, Martinsried, Germany
| | - Ana P Gamiz-Hernandez
- Department of Biochemistry and Biophysics, Stockholm University, SE-106 91, Stockholm, Sweden
- Center of Integrated Protein Science at the Department of Chemistry, Technical University of Munich, Garching, Germany
| | - Genji Kurisu
- Institute for Protein Research, Osaka University, Suita, Osaka, 565-0871, Japan
- Department of Macromolecular Science, Graduate School of Science, Osaka University, Toyonaka, 560-0043, Japan
| | - Marc M Nowaczyk
- Plant Biochemistry, Faculty of Biology and Biotechnology, Ruhr University Bochum, 44780, Bochum, Germany.
| | - Ville R I Kaila
- Department of Biochemistry and Biophysics, Stockholm University, SE-106 91, Stockholm, Sweden.
- Center of Integrated Protein Science at the Department of Chemistry, Technical University of Munich, Garching, Germany.
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Dugalic P, Djuranovic S, Pavlovic-Markovic A, Dugalic V, Tomasevic R, Gluvic Z, Obradovic M, Bajic V, Isenovic ER. Proton Pump Inhibitors and Radiofrequency Ablation for Treatment of Barrett's Esophagus. Mini Rev Med Chem 2020; 20:975-987. [PMID: 31644405 DOI: 10.2174/1389557519666191015203636] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 06/04/2019] [Accepted: 06/25/2019] [Indexed: 02/07/2023]
Abstract
Gastroesophageal Reflux Disease (GERD) is characterized by acid and bile reflux in the distal oesophagus, and this may cause the development of reflux esophagitis and Barrett's oesophagus (BE). The natural histological course of untreated BE is non-dysplastic or benign BE (ND), then lowgrade (LGD) and High-Grade Dysplastic (HGD) BE, with the expected increase in malignancy transfer to oesophagal adenocarcinoma (EAC). The gold standard for BE diagnostics involves high-resolution white-light endoscopy, followed by uniform endoscopy findings description (Prague classification) with biopsy performance according to Seattle protocol. The medical treatment of GERD and BE includes the use of proton pump inhibitors (PPIs) regarding symptoms control. It is noteworthy that long-term use of PPIs increases gastrin level, which can contribute to transfer from BE to EAC, as a result of its effects on the proliferation of BE epithelium. Endoscopy treatment includes a wide range of resection and ablative techniques, such as radio-frequency ablation (RFA), often concomitantly used in everyday endoscopy practice (multimodal therapy). RFA promotes mucosal necrosis of treated oesophagal region via high-frequency energy. Laparoscopic surgery, partial or total fundoplication, is reserved for PPIs and endoscopy indolent patients or in those with progressive disease. This review aims to explain distinct effects of PPIs and RFA modalities, illuminate certain aspects of molecular mechanisms involved, as well as the effects of their concomitant use regarding the treatment of BE and prevention of its transfer to EAC.
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Affiliation(s)
- Predrag Dugalic
- Department of Gastroenterology and Hepatology, University Clinical-Hospital Centre Zemun-Belgrade, Belgrade, Serbia
| | - Srdjan Djuranovic
- Clinical Centre of Serbia, Clinic for Gastroenterology and Hepatology, Faculty of Medicine, University of Belgrade, Belgrade, Serbia
| | - Aleksandra Pavlovic-Markovic
- Clinical Centre of Serbia, Clinic for Gastroenterology and Hepatology, Faculty of Medicine, University of Belgrade, Belgrade, Serbia
| | - Vladimir Dugalic
- Clinical Centre of Serbia, Clinic for Surgery, Faculty of Medicine, University of Belgrade, Belgrade, Serbia
| | - Ratko Tomasevic
- Department of Gastroenterology and Hepatology, Faculty of Medicine, University of Belgrade, University Clinical-Hospital Centre Zemun-Belgrade, Belgrade, Serbia
| | - Zoran Gluvic
- Department of Endocrinology and Diabetes, Faculty of Medicine, University of Belgrade, University Clinical-Hospital Centre Zemun-Belgrade, Belgrade, Serbia
| | - Milan Obradovic
- Department of Radiobiology and Molecular Genetics, Institute of Nuclear Sciences Vinca, University of Belgrade, Belgrade, Serbia
| | - Vladan Bajic
- Department of Radiobiology and Molecular Genetics, Institute of Nuclear Sciences Vinca, University of Belgrade, Belgrade, Serbia
| | - Esma R Isenovic
- Department of Radiobiology and Molecular Genetics, Institute of Nuclear Sciences Vinca, University of Belgrade, Belgrade, Serbia
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Singh A, Marcoline FV, Veshaguri S, Kao AW, Bruchez M, Mindell JA, Stamou D, Grabe M. Protons in small spaces: Discrete simulations of vesicle acidification. PLoS Comput Biol 2019; 15:e1007539. [PMID: 31869334 PMCID: PMC6946529 DOI: 10.1371/journal.pcbi.1007539] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 01/07/2020] [Accepted: 11/11/2019] [Indexed: 12/23/2022] Open
Abstract
The lumenal pH of an organelle is one of its defining characteristics and central to its biological function. Experiments have elucidated many of the key pH regulatory elements and how they vary from compartment-to-compartment, and continuum mathematical models have played an important role in understanding how these elements (proton pumps, counter-ion fluxes, membrane potential, buffering capacity, etc.) work together to achieve specific pH setpoints. While continuum models have proven successful in describing ion regulation at the cellular length scale, it is unknown if they are valid at the subcellular level where volumes are small, ion numbers may fluctuate wildly, and biochemical heterogeneity is large. Here, we create a discrete, stochastic (DS) model of vesicular acidification to answer this question. We used this simplified model to analyze pH measurements of isolated vesicles containing single proton pumps and compared these results to solutions from a continuum, ordinary differential equations (ODE)-based model. Both models predict similar parameter estimates for the mean proton pumping rate, membrane permeability, etc., but, as expected, the ODE model fails to report on the fluctuations in the system. The stochastic model predicts that pH fluctuations decrease during acidification, but noise analysis of single-vesicle data confirms our finding that the experimental noise is dominated by the fluorescent dye, and it reveals no insight into the true noise in the proton fluctuations. Finally, we again use the reduced DS model explore the acidification of large, lysosome-like vesicles to determine how stochastic elements, such as variations in proton-pump copy number and cycling between on and off states, impact the pH setpoint and fluctuations around this setpoint. Organelles harbor specific ion channels, transporters, and other molecular components that allow them to achieve specific intracellular ionic conditions required for their proper function. How all of these components work together to regulate these concentrations, such as maintaining a specific pH value, is complex, and continuum mathematical models have been helpful for evaluating different mechanisms and making quantitative predictions that can be tested experimentally. Nonetheless, organelles can be quite small and some contain only a handful of free protons—can continuum models accurately describe systems with so few molecules? We tested this by creating a discrete, stochastic (DS) model of vesicle acidification that tracks how all of these individual molecules in the vesicle change their state in time. When fitting experimental data, the DS model provides the same parameter estimates as a corresponding continuum model, indicating that both models are equally valid. However, the DS model additionally informs on the noise in the vesicle. When compared to the experimental noise in pH, we show that there is no agreement, because experimental fluctuations do not report on the true pH fluctuations, but rather they report on the fluctuations in reporter molecule protonation. Given experimental limitations, our result highlights the importance of DS models in predicting noise in organelles.
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Affiliation(s)
- Apeksha Singh
- College of Letters and Science, University of California Berkeley, Berkeley, California, United States of America
- Cardiovascular Research Institute, Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California, United States of America
| | - Frank V. Marcoline
- Cardiovascular Research Institute, Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California, United States of America
- * E-mail: (FVM); (MG)
| | - Salome Veshaguri
- Bionanotecnology and Nanomedicine Laboratory, University of Copenhagen, Copenhagen, Denmark
- Department of Chemistry, University of Copenhagen, Copenhagen, Denmark
- Nano-Science Center, University of Copenhagen, Copenhagen, Denmark
- Lundbeck Foundation Center Biomembranes in Nanomedicine, University of Copenhagen, Copenhagen, Denmark
| | - Aimee W. Kao
- Memory and Aging Center, Department of Neurology, University of California San Francisco, San Francisco, California, United States of America
| | - Marcel Bruchez
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
- Molecular Biosensor and Imaging Center, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
| | - Joseph A. Mindell
- Membrane Transport Biophysics Unit, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Dimitrios Stamou
- Bionanotecnology and Nanomedicine Laboratory, University of Copenhagen, Copenhagen, Denmark
- Department of Chemistry, University of Copenhagen, Copenhagen, Denmark
- Nano-Science Center, University of Copenhagen, Copenhagen, Denmark
- Lundbeck Foundation Center Biomembranes in Nanomedicine, University of Copenhagen, Copenhagen, Denmark
| | - Michael Grabe
- Cardiovascular Research Institute, Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California, United States of America
- * E-mail: (FVM); (MG)
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Shi CY, Hussain SB, Yang H, Bai YX, Khan MA, Liu YZ. CsPH8, a P-type proton pump gene, plays a key role in the diversity of citric acid accumulation in citrus fruits. Plant Sci 2019; 289:110288. [PMID: 31623791 DOI: 10.1016/j.plantsci.2019.110288] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 09/18/2019] [Accepted: 09/25/2019] [Indexed: 06/10/2023]
Abstract
Citric acid homeostasis patterns and its content are diversified among the fruits of citrus cultivars, but the cause remained unclear. In this study we showed that changes of citric acid content were highly associated with the expression profiles of a P-type proton pump gene (CsPH8) in the fruits of six citrus cultivars; moreover, analysis of 21 different fruit samples indicated that the correlation coefficient between titratable acid content and CsPH8 transcript level was 0.5837 with a significant level (P < 0.05). Overexpression of CsPH8 in acidless pumelo juice sacs, strawberry fruit, and tomato fruit significantly increased the titratable acid or citric acid content besides the gene transcript level. On another hand, RNA interference of CsPH8 in acidic pumelo juice sacs significantly decreased the CsPH8 transcript level and the titratable acid or citric acid content as well. In addition, severe drought significantly increased the CsPH8 transcript level besides the titratable acid content. Taken together, these findings address the function of CsPH8 in citrus vacuolar acidification, confirm that CsPH8 plays a key role in the variation of citric acid content, and supported that the acid fluctuation influenced by drought, is at least partly due to the change of CsPH8 transcript level.
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Affiliation(s)
- Cai-Yun Shi
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), Huazhong Agricultural University, Wuhan 430070, PR China; College of Horticulture & Forestry Sciences, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Syed Bilal Hussain
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), Huazhong Agricultural University, Wuhan 430070, PR China; College of Horticulture & Forestry Sciences, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Huan Yang
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), Huazhong Agricultural University, Wuhan 430070, PR China; College of Horticulture & Forestry Sciences, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Ying-Xin Bai
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), Huazhong Agricultural University, Wuhan 430070, PR China; College of Horticulture & Forestry Sciences, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Muhammad Abbas Khan
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), Huazhong Agricultural University, Wuhan 430070, PR China; College of Horticulture & Forestry Sciences, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Yong-Zhong Liu
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), Huazhong Agricultural University, Wuhan 430070, PR China; College of Horticulture & Forestry Sciences, Huazhong Agricultural University, Wuhan 430070, PR China.
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Vergara C, Araujo KEC, Sperandio MVL, Santos LA, Urquiaga S, Zilli JÉ. Dark septate endophytic fungi increase the activity of proton pumps, efficiency of 15N recovery from ammonium sulphate, N content, and micronutrient levels in rice plants. Braz J Microbiol 2019; 50:825-838. [PMID: 31090019 PMCID: PMC6863334 DOI: 10.1007/s42770-019-00092-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [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: 01/30/2019] [Accepted: 05/04/2019] [Indexed: 11/25/2022] Open
Abstract
Plants colonised by dark septate endophytic (DSE) fungi show increased uptake of nutrients available in the environment. The objective of the present study was to evaluate the impact of DSE fungi on the activity of proton pumps, nitrogen (N) recovery from ammonium sulphate, and nutrient accumulation in rice plants. Treatments consisted of non-inoculated plants and plants inoculated with two isolates of DSE fungi, A101 and A103. To determine N recovery from the soil, ammonium sulphate enriched with 15N was added to a non-sterile substrate while parameters associated with the activity of proton pumps and with NO3- uptake were determined in a sterile environment. The A101 and A103 fungal isolates colonised the roots of rice plants, promoting 15N uptake, growth, and accumulation of nutrients as compared with the mock control. A103 induced the expression of the plasma membrane H+-ATPase (PM H+-ATPase) isoforms OsA5 and OsA8, the activity of the PM H+-ATPase and H+-pyrophosphatase. Our results suggest that the inoculation of rice plants with DSE fungi represents a strategy to improve the N recovery from ammonium sulphate and rice plant growth through the induction of OsA5 and OsA8 isoforms and stimulation of the PM H+-ATPase and H+-pyrophosphatase.
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Affiliation(s)
- Carlos Vergara
- Universidade Federal Rural do Rio de Janeiro, Instituto de Agronomia, Seropédica, RJ, Brazil
| | | | | | - Leandro Azevedo Santos
- Universidade Federal Rural do Rio de Janeiro, Instituto de Agronomia, Seropédica, RJ, Brazil
| | - Segundo Urquiaga
- Embrapa Agrobiologia, BR 465, km 07, Seropédica, RJ, 23891-000, Brazil
| | - Jerri Édson Zilli
- Embrapa Agrobiologia, BR 465, km 07, Seropédica, RJ, 23891-000, Brazil.
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Liao Q, Jian SF, Song HX, Guan CY, Lepo JE, Ismail AM, Zhang ZH. Balance between nitrogen use efficiency and cadmium tolerance in Brassica napus and Arabidopsis thaliana. Plant Sci 2019; 284:57-66. [PMID: 31084879 DOI: 10.1016/j.plantsci.2019.04.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 03/30/2019] [Accepted: 04/02/2019] [Indexed: 05/14/2023]
Abstract
The transmembrane transport of NO3- and Cd2+ into plant cell vacuoles relies on the energy from their tonoplast proton pumps, V-ATPase and V-PPase. If the activity of these pumps is reduced, it results in less NO3- and Cd2+ being transported into the vacuoles, which contributes to better nitrogen use efficiency (NUE) and lower Cd2+ tolerance in plants. The physiological mechanisms that regulate the balance between NUE and Cd2+ tolerance remain unknown. In our study, two Brassica napus genotypes with differential NUEs, xiangyou 15 and 814, and Atclca-2 mutant and AtCAX4 over-expression line (AtCAX4-OE) of Arabidopsis thaliana, were used to investigate Cd2+ stress responses. We found that the Brassica napus genotype, with higher NUE, was more sensitive to Cd2+ stress. The AtCAX4-OE mutant, with higher Cd2+ vacuolar sequestration capacity (VSC), limited NO3- sequestration into root vacuoles and promoted NUE. Atclca-2 mutants, with decreased NO3- VSC, enhanced Cd2+ sequestration into root vacuoles and conferred greater Cd2+ tolerance than the WT. This may be due to the competition between Cd2+ andNO3- in the vacuoles for the energy provided by V-ATPase and V-PPase. Regulating the balance between Cd2+ and NO3- vacuolar accumulation by inhibiting the activity of CLCa transporter and increasing the activity of CAX4 transporter will simultaneously enhance both the NUE and Cd2+ tolerance of Brassica napus, essential for improving its Cd2+ phytoremediation potential.
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Affiliation(s)
- Qiong Liao
- Southern Regional Collaborative Innovation Center for Grain and Oil Crops in China, College of Resources and Environmental Sciences, Hunan Agricultural University, Changsha, China
| | - Shao-Fen Jian
- Southern Regional Collaborative Innovation Center for Grain and Oil Crops in China, College of Resources and Environmental Sciences, Hunan Agricultural University, Changsha, China
| | - Hai-Xing Song
- Southern Regional Collaborative Innovation Center for Grain and Oil Crops in China, College of Resources and Environmental Sciences, Hunan Agricultural University, Changsha, China; National Engineering Laboratory of High Efficiency Utilization of Soil and Fertilizer Resources, Hunan Agricultural University, Changsha, China
| | - Chun-Yun Guan
- National Center of Oilseed Crops Improvement, Hunan Branch, Changsha, China
| | - Joe Eugene Lepo
- Center for Environmental Diagnostics and Bioremediation, University of West Florida, Pensacola, FL, 32514, United States
| | - Abdelbagi M Ismail
- International Rice Research Institute, DAPO 7777, Metro Manila, Philippines
| | - Zhen-Hua Zhang
- Southern Regional Collaborative Innovation Center for Grain and Oil Crops in China, College of Resources and Environmental Sciences, Hunan Agricultural University, Changsha, China; National Engineering Laboratory of High Efficiency Utilization of Soil and Fertilizer Resources, Hunan Agricultural University, Changsha, China.
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Saotome K, Teng B, Tsui CCA, Lee WH, Tu YH, Kaplan JP, Sansom MSP, Liman ER, Ward AB. Structures of the otopetrin proton channels Otop1 and Otop3. Nat Struct Mol Biol 2019; 26:518-525. [PMID: 31160780 PMCID: PMC6564688 DOI: 10.1038/s41594-019-0235-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Accepted: 04/26/2019] [Indexed: 01/08/2023]
Abstract
Otopetrins (Otop1-Otop3) comprise one of two known eukaryotic proton-selective channel families. Otop1 is required for otoconia formation and a candidate mammalian sour taste receptor. Here we report cryo-EM structures of zebrafish Otop1 and chicken Otop3 in lipid nanodiscs. The structures reveal a dimeric architecture, with each subunit forming 12 transmembrane helices divided into structurally similar amino (N) and carboxy (C) domains. Cholesterol-like molecules occupy various sites in Otop1 and Otop3 and occlude a central tunnel. In molecular dynamics simulations, hydrophilic vestibules formed by the N and C domains and in the intrasubunit interface between N and C domains form conduits for water entry into the membrane core, suggesting three potential proton conduction pathways. By mutagenesis, we tested the roles of charged residues in each putative permeation pathway. Our results provide a structural basis for understanding selective proton permeation and gating of this conserved family of proton channels.
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Affiliation(s)
- Kei Saotome
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, USA
- Howard Hughes Medical Institute, Department of Neuroscience, Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, CA, USA
| | - Bochuan Teng
- Section of Neurobiology, Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| | - Che Chun Alex Tsui
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, USA
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Wen-Hsin Lee
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, USA
| | - Yu-Hsiang Tu
- Section of Neurobiology, Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| | - Joshua P Kaplan
- Section of Neurobiology, Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| | - Mark S P Sansom
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Emily R Liman
- Section of Neurobiology, Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA.
| | - Andrew B Ward
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, USA.
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Murphy JT, Liu H, Ma X, Shaver A, Egan BM, Oh C, Boyko A, Mazer T, Ang S, Khopkar R, Javaheri A, Kumar S, Jiang X, Ory D, Mani K, Matkovich SJ, Kornfeld K, Diwan A. Simple nutrients bypass the requirement for HLH-30 in coupling lysosomal nutrient sensing to survival. PLoS Biol 2019; 17:e3000245. [PMID: 31086360 PMCID: PMC6516633 DOI: 10.1371/journal.pbio.3000245] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2019] [Accepted: 04/10/2019] [Indexed: 12/11/2022] Open
Abstract
Lysosomes are ubiquitous acidified organelles that degrade intracellular and extracellular material trafficked via multiple pathways. Lysosomes also sense cellular nutrient levels to regulate target of rapamycin (TOR) kinase, a signaling enzyme that drives growth and suppresses activity of the MiT/TFE family of transcription factors that control biogenesis of lysosomes. In this study, we subjected worms lacking basic helix–loop–helix transcription factor 30 (hlh-30), the Caenorhabditis elegans MiT/TFE ortholog, to starvation followed by refeeding to understand how this pathway regulates survival with variable nutrient supply. Loss of HLH-30 markedly impaired survival in starved larval worms and recovery upon refeeding bacteria. Remarkably, provision of simple nutrients in a completely defined medium (C. elegans maintenance medium [CeMM]), specifically glucose and linoleic acid, restored lysosomal acidification, TOR activation, and survival with refeeding despite the absence of HLH-30. Worms deficient in lysosomal lipase 2 (lipl-2), a lysosomal enzyme that is transcriptionally up-regulated in starvation in an HLH-30–dependent manner, also demonstrated increased mortality with starvation–refeeding that was partially rescued with glucose, suggesting a critical role for LIPL-2 in lipid metabolism under starvation. CeMM induced transcription of vacuolar proton pump subunits in hlh-30 mutant worms, and knockdown of vacuolar H+-ATPase 12 (vha-12) and its upstream regulator, nuclear hormone receptor 31 (nhr-31), abolished the rescue with CeMM. Loss of Ras-related GTP binding protein C homolog 1 RAGC-1, the ortholog for mammalian RagC/D GTPases, conferred starvation–refeeding lethality, and RAGC-1 overexpression was sufficient to rescue starved hlh-30 mutant worms, demonstrating a critical need for TOR activation with refeeding. These results show that HLH-30 activation is critical for sustaining survival during starvation–refeeding stress via regulating TOR. Glucose and linoleic acid bypass the requirement for HLH-30 in coupling lysosome nutrient sensing to survival. Lysosomes play a central role in coupling the nutrient state of the cell to growth and survival decisions. This study uncovers a critical role for HLH-30, the nematode ortholog of the mammalian MiT/TFE family of master regulators of lysosome biogenesis, in survival under starvation and refeeding conditions. Refeeding simple nutrients bypasses the requirement for HLH-30 to permit survival.
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Affiliation(s)
- John T. Murphy
- Center for Cardiovascular Research and Division of Cardiology, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Haiyan Liu
- Center for Cardiovascular Research and Division of Cardiology, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
- John Cochran VA Medical Center, St. Louis, Missouri, United States of America
| | - Xiucui Ma
- Center for Cardiovascular Research and Division of Cardiology, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
- John Cochran VA Medical Center, St. Louis, Missouri, United States of America
| | - Alex Shaver
- Center for Cardiovascular Research and Division of Cardiology, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Brian M. Egan
- Center for Cardiovascular Research and Division of Cardiology, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Clara Oh
- Center for Cardiovascular Research and Division of Cardiology, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Alexander Boyko
- Center for Cardiovascular Research and Division of Cardiology, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Travis Mazer
- Center for Cardiovascular Research and Division of Cardiology, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Samuel Ang
- Center for Cardiovascular Research and Division of Cardiology, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Rohan Khopkar
- Center for Cardiovascular Research and Division of Cardiology, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Ali Javaheri
- Center for Cardiovascular Research and Division of Cardiology, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Sandeep Kumar
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Xuntian Jiang
- Center for Cardiovascular Research and Division of Cardiology, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Daniel Ory
- Center for Cardiovascular Research and Division of Cardiology, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Kartik Mani
- Center for Cardiovascular Research and Division of Cardiology, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
- John Cochran VA Medical Center, St. Louis, Missouri, United States of America
| | - Scot J. Matkovich
- Center for Cardiovascular Research and Division of Cardiology, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Kerry Kornfeld
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Abhinav Diwan
- Center for Cardiovascular Research and Division of Cardiology, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
- John Cochran VA Medical Center, St. Louis, Missouri, United States of America
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri, United States of America
- * E-mail:
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Muid KA, Kimyon Ö, Reza SH, Karakaya HC, Koc A. Characterization of long living yeast deletion mutants that lack mitochondrial metabolism genes DSS1, PPA2 and AFG3. Gene 2019; 706:172-180. [PMID: 31082499 DOI: 10.1016/j.gene.2019.05.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [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: 08/13/2018] [Revised: 04/15/2019] [Accepted: 05/01/2019] [Indexed: 02/06/2023]
Abstract
Molecular mechanisms of aging and longevity are still mostly unknown. Mitochondria play central roles in cellular metabolism and aging. In this study, we identified three deletion mutants of mitochondrial metabolism genes (ppa2∆, dss1∆, and afg3∆) that live longer than wild-type cells. These long-lived cells harbored significantly decreased amount of mitochondrial DNA (mtDNA) and reactive oxygen species (ROS). Compared to the serpentine nature of wild-type mitochondria, a different dynamics and distribution pattern of mitochondria were observed in the mutants. Both young and old long-lived cells produced relatively low but adequate levels of ATP for cellular activities. The status of the retrograde signaling was checked by expression of CIT2 gene and found activated in long-lived mutants. The mutant cells were also profiled for their gene expression patterns, and genes that were differentially regulated were determined. All long-lived cells comprised similar pleiotropic phenotype regarding mitochondrial dynamics and functions. Thus, this study suggests that DSS1, PPA2, and AFG3 genes modulate the lifespan by altering the mitochondrial morphology and functions.
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Affiliation(s)
- K A Muid
- Izmir Institute of Technology, Department of Molecular Biology and Genetics, 35430 Urla, Izmir, Turkey
| | - Önder Kimyon
- Izmir Institute of Technology, Department of Molecular Biology and Genetics, 35430 Urla, Izmir, Turkey
| | - Shahadat Hasan Reza
- Izmir Institute of Technology, Department of Molecular Biology and Genetics, 35430 Urla, Izmir, Turkey
| | - Huseyin Caglar Karakaya
- Izmir Institute of Technology, Department of Molecular Biology and Genetics, 35430 Urla, Izmir, Turkey
| | - Ahmet Koc
- Izmir Institute of Technology, Department of Molecular Biology and Genetics, 35430 Urla, Izmir, Turkey; Inonu University, Medical School, Department of Medical Biology and Genetics, Battalgazi, Malatya, Turkey.
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Wang R, Chen B, Wang T, Li P, Ding F. Effects of chlorine dioxide on the germination, oxidative metabolism and growth of barley seedlings (Hordeum vulgare L.). Sci Rep 2019; 9:5765. [PMID: 30962491 PMCID: PMC6453926 DOI: 10.1038/s41598-019-42295-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 03/28/2019] [Indexed: 11/09/2022] Open
Abstract
The effects of chlorine dioxide, ClO2, on the germination, oxidative metabolism and growth of barley seedlings were investigated. Barley seeds were separately treated with 0, 500, 1000 and 2000 mg.L-1 ClO2 solutions. Differences in the percentage of seed germination were observed in treatments with 1000 and 2000 mg.L-1 ClO2 solutions only. However, 1000 and 2000 mg.L-1 ClO2 significantly decreased the germination percentage. No significant difference in the MDA content, electrolyte leakage and amount of chlorophyll was observed in seedlings germinated from seeds treated with 0, 500 and 1000 mg.L-1 of ClO2. Similarly, POD and CAT activities showed no significant differences in seedlings germinated from seeds treated with 0 and 500 mg.L-1 while with 1000 mg.L-1 ClO2 there was an increase of these activities. Although there was no significant difference in the above ground part fresh weight between barley seedlings in which seeds were treated with distilled water and ClO2, the fresh weight of barley roots in which seeds were treated with ClO2 was significantly higher than that of control. The total length of barley roots and the number of roots were also increased. The lignin content of barley roots was markly reduced. Staining with Evans blue indicated that barley roots were not obviously damaged. Furtherly, the stimulation of the cell membrane H+-ATPase activity and root activity were observed to be induced by ClO2.
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Affiliation(s)
- Ruiming Wang
- Institutional affiliations: State Key Laboratory of Biobased Material and Green Papermaking (LBMP), Shandong Provincial Key Laboratory of Microbial Engineering, College of Food Science and Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, 250353, P.R. China
| | - Bingcui Chen
- Institutional affiliations: State Key Laboratory of Biobased Material and Green Papermaking (LBMP), Shandong Provincial Key Laboratory of Microbial Engineering, College of Food Science and Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, 250353, P.R. China
| | - Tengfei Wang
- Institutional affiliations: State Key Laboratory of Biobased Material and Green Papermaking (LBMP), Shandong Provincial Key Laboratory of Microbial Engineering, College of Food Science and Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, 250353, P.R. China
| | - Piwu Li
- Institutional affiliations: State Key Laboratory of Biobased Material and Green Papermaking (LBMP), Shandong Provincial Key Laboratory of Microbial Engineering, College of Food Science and Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, 250353, P.R. China
| | - Feng Ding
- Institutional affiliations: State Key Laboratory of Biobased Material and Green Papermaking (LBMP), Shandong Provincial Key Laboratory of Microbial Engineering, College of Food Science and Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, 250353, P.R. China.
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Shin JH, Mila I, Liu M, Rodrigues MA, Vernoux T, Pirrello J, Bouzayen M. The RIN-regulated Small Auxin-Up RNA SAUR69 is involved in the unripe-to-ripe phase transition of tomato fruit via enhancement of the sensitivity to ethylene. New Phytol 2019; 222:820-836. [PMID: 30511456 DOI: 10.1111/nph.15618] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 11/24/2018] [Indexed: 05/22/2023]
Abstract
Ethylene is the main hormone controlling climacteric fruit ripening; however, the mechanisms underlying the developmental transition leading to the initiation of the ripening process remain elusive, although the presumed role of active hormone interplay has often been postulated. To unravel the putative role of auxin in the unripe-to-ripe transition, we investigated the dynamics of auxin activity in tomato fruit and addressed the physiological significance of Sl-SAUR69, previously identified as a RIN target gene, using reverse genetics approaches. Auxin signalling undergoes dramatic decline at the onset of ripening in wild-type fruit, but not in the nonripening rin mutant. Sl-SAUR69 exhibits reduced expression in rin and its up-regulation results in premature initiation of ripening, whereas its down-regulation extends the time to ripening. Overexpression of Sl-SAUR69 reduces proton pump activity and polar auxin transport, and ectopic expression in Arabidopsis alters auxin transporter abundance, further arguing for its active role in the regulation of auxin transport. The data support a model in which Sl-SAUR69 represses auxin transport, thus generating auxin minima, which results in enhanced ethylene sensitivity. This defines a regulation loop, fed by ethylene and auxin as the main hormonal signals and by RIN and Sl-SAUR69 as modulators of the balance between the two hormones.
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Affiliation(s)
- Jun-Hye Shin
- GBF Laboratory, Université de Toulouse, INRA, Castanet-Tolosan, 31320, France
| | - Isabelle Mila
- GBF Laboratory, Université de Toulouse, INRA, Castanet-Tolosan, 31320, France
| | - Mingchun Liu
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610065, Sichuan, China
| | - Maria Aurineide Rodrigues
- GBF Laboratory, Université de Toulouse, INRA, Castanet-Tolosan, 31320, France
- Laboratory of Plant Physiology, Institute of Biosciences, Department of Botany, Universidade de São Paulo, São Paulo, 11461, Brazil
| | - Teva Vernoux
- Laboratoire de Reproduction et Développement des Plantes, CNRS, INRA, ENS de Lyon, UCBL, Université de Lyon, Lyon, 69364, France
| | - Julien Pirrello
- GBF Laboratory, Université de Toulouse, INRA, Castanet-Tolosan, 31320, France
| | - Mondher Bouzayen
- GBF Laboratory, Université de Toulouse, INRA, Castanet-Tolosan, 31320, France
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Abstract
The cytochrome bo3 quinol oxidase from Vitreoscilla (vbo3) catalyses oxidation of ubiquinol and reduction of O2 to H2O. Data from earlier studies suggested that the free energy released in this reaction is used to pump sodium ions instead of protons across a membrane. Here, we have studied the functional properties of heterologously expressed vbo3 with a variety of methods. (i) Following oxygen consumption with a Clark-type electrode, we did not observe a measurable effect of Na+ on the oxidase activity of purified vbo3 solubilized in detergent or reconstituted in liposomes. (ii) Using fluorescent dyes, we find that vbo3 does not pump Na+ ions, but H+ across the membrane, and that H+-pumping is not influenced by the presence of Na+. (iii) Using an oxygen pulse method, it was found that 2 H+/e- are ejected from proteoliposomes, in agreement with the values found for the H+-pumping bo3 oxidase of Escherichia coli (ecbo3). This coincides with the interpretation that 1 H+/e- is pumped across the membrane and 1 H+/e- is released during quinol oxidation. (iv) When the electron transfer kinetics of vbo3 upon reaction with oxygen were followed in single turnover experiments, a similar sequence of reaction steps was observed as reported for the E. coli enzyme and none of these reactions was notably affected by the presence of Na+. Overall the data show that vbo3 is a proton pumping terminal oxidase, behaving similarly to the Escherichia coli bo3 quinol oxidase.
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Affiliation(s)
- Simone Graf
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012, Bern, Switzerland
| | - Peter Brzezinski
- Department of Biochemistry and Biophysics, The Arrhenius Laboratories for Natural Sciences, Stockholm University, SE-106 91, Stockholm, Sweden
| | - Christoph von Ballmoos
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012, Bern, Switzerland.
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Mehta G, Anbalagan GK, Bharati AP, Gadre P, Ghosh SK. An interplay between Shugoshin and Spo13 for centromeric cohesin protection and sister kinetochore mono-orientation during meiosis I in Saccharomyces cerevisiae. Curr Genet 2018; 64:1141-1152. [PMID: 29644457 DOI: 10.1007/s00294-018-0832-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [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: 01/06/2018] [Revised: 03/24/2018] [Accepted: 04/03/2018] [Indexed: 10/17/2022]
Abstract
Meiosis is a specialized cell division process by which haploid gametes are produced from a diploid mother cell. Reductional chromosome segregation during meiosis I (MI) is achieved by two unique and conserved events: centromeric cohesin protection (CCP) and sister kinetochore mono-orientation (SKM). In Saccharomyces cerevisiae, a meiosis-specific protein Spo13 plays a role in both these centromere-specific events. Despite genome-wide association of Spo13, we failed to detect its function in global processes such as cohesin loading, cohesion establishment and homologs pairing. While Shugoshin (Sgo1) and protein phosphatase 2A (PP2ARts1) play a central role in CCP, it is not fully understood whether Spo13 functions in the process through a Sgo1- PP2ARts1-dependent or -independent mechanism. To delineate this and to find the relative contribution of each of these proteins in CCP and SKM, we meticulously observed the sister chromatid segregation pattern in the wild type, sgo1Δ, rts1Δ and spo13Δ single mutants and in their respective double mutants. We found that Spo13 protects centromeric cohesin through a Sgo1- PP2ARts1-independent mechanism. To our surprise, we observed a hitherto unknown role of Sgo1 in SKM. Further investigation revealed that Sgo1-mediated recruitment of aurora kinase Ipl1 to the centromere facilitates monopolin loading at the kinetochore during MI. Hence, this study uncovers the role of Sgo1 in SKM and demonstartes how the regulators (Sgo1, PP2ARts1, Spo13) work in a coordinated manner to achieve faithful chromosome segregation during meiosis, the failure of which leads to aneuploidy and birth defects.
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Affiliation(s)
- Gunjan Mehta
- National Cancer Institute, National Institutes of Health, 41 Medlars Drive, Bethesda, MD, 20892, USA
| | | | - Akhilendra Pratap Bharati
- Department of Biosciences and Bioengineering, Indian Institute of Technology, Bombay, Powai, Mumbai, 400076, India
| | - Purna Gadre
- B231, Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, 400005, India
| | - Santanu Kumar Ghosh
- Department of Biosciences and Bioengineering, Indian Institute of Technology, Bombay, Powai, Mumbai, 400076, India.
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Hippler FWR, Mattos-Jr D, Boaretto RM, Williams LE. Copper excess reduces nitrate uptake by Arabidopsis roots with specific effects on gene expression. J Plant Physiol 2018; 228:158-165. [PMID: 29933138 PMCID: PMC6090090 DOI: 10.1016/j.jplph.2018.06.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 06/09/2018] [Accepted: 06/10/2018] [Indexed: 05/09/2023]
Abstract
Nitrate uptake by plants is mediated by specific transport proteins in roots (NRTs), which are also dependent on the activity of proton pumps that energize the reaction. Nitrogen (N) metabolism in plants is sensitive to copper (Cu) toxicity conditions. To understand how Cu affects the uptake and assimilation processes, this study assesses the inhibitory effects of elevated Cu levels on the expression of genes related to N absorption, transport and assimilation in roots of Arabidopsis. Plants were grown hydroponically for 45 days, being exposed to a range of Cu concentrations in the last 72 h or alternatively exposed to 5.0 μM Cu for the last 15 days. High Cu levels decreased the uptake and accumulation of N in plants. It down-regulated the expression of genes encoding nitrate reductase (NR1), low-affinity nitrate transporters (NRT1 family) and bZIP transcription factors (TGA1 and TGA4) that regulate the expression of nitrate transporters. Cu toxicity also specifically down-regulated the plasma membrane proton pump, AHA2, whilst having little effect on AHA1 and AHA5. In contrast, there was an up-regulation of high-affinity nitrate transporters from the NRT2 family when exposed to medium level of Cu excess, but this was insufficient for restoring N absorption by roots to control levels. These results demonstrate that plants display specific responses to Cu toxicity, modulating the expression of particular genes related to nitrate uptake, such as low-affinity nitrate transporters and proton pumps.
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Affiliation(s)
- Franz W R Hippler
- Centro de Citricultura Sylvio Moreira, Instituto Agronômico (IAC), Rod. Anhanguera, km 158, CP 04, CEP 13490-970, Cordeirópolis, SP, Brazil; University of Southampton, Biological Sciences, Building 85, Highfield, Southampton SO17 1BJ, United Kingdom.
| | - Dirceu Mattos-Jr
- Centro de Citricultura Sylvio Moreira, Instituto Agronômico (IAC), Rod. Anhanguera, km 158, CP 04, CEP 13490-970, Cordeirópolis, SP, Brazil
| | - Rodrigo M Boaretto
- Centro de Citricultura Sylvio Moreira, Instituto Agronômico (IAC), Rod. Anhanguera, km 158, CP 04, CEP 13490-970, Cordeirópolis, SP, Brazil
| | - Lorraine E Williams
- University of Southampton, Biological Sciences, Building 85, Highfield, Southampton SO17 1BJ, United Kingdom.
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Graus D, Konrad KR, Bemm F, Patir Nebioglu MG, Lorey C, Duscha K, Güthoff T, Herrmann J, Ferjani A, Cuin TA, Roelfsema MRG, Schumacher K, Neuhaus HE, Marten I, Hedrich R. High V-PPase activity is beneficial under high salt loads, but detrimental without salinity. New Phytol 2018; 219:1421-1432. [PMID: 29938800 PMCID: PMC6099232 DOI: 10.1111/nph.15280] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Accepted: 05/15/2018] [Indexed: 05/03/2023]
Abstract
The membrane-bound proton-pumping pyrophosphatase (V-PPase), together with the V-type H+ -ATPase, generates the proton motive force that drives vacuolar membrane solute transport. Transgenic plants constitutively overexpressing V-PPases were shown to have improved salinity tolerance, but the relative impact of increasing PPi hydrolysis and proton-pumping functions has yet to be dissected. For a better understanding of the molecular processes underlying V-PPase-dependent salt tolerance, we transiently overexpressed the pyrophosphate-driven proton pump (NbVHP) in Nicotiana benthamiana leaves and studied its functional properties in relation to salt treatment by primarily using patch-clamp, impalement electrodes and pH imaging. NbVHP overexpression led to higher vacuolar proton currents and vacuolar acidification. After 3 d in salt-untreated conditions, V-PPase-overexpressing leaves showed a drop in photosynthetic capacity, plasma membrane depolarization and eventual leaf necrosis. Salt, however, rescued NbVHP-hyperactive cells from cell death. Furthermore, a salt-induced rise in V-PPase but not of V-ATPase pump currents was detected in nontransformed plants. The results indicate that under normal growth conditions, plants need to regulate the V-PPase pump activity to avoid hyperactivity and its negative feedback on cell viability. Nonetheless, V-PPase proton pump function becomes increasingly important under salt stress for generating the pH gradient necessary for vacuolar proton-coupled Na+ sequestration.
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Affiliation(s)
- Dorothea Graus
- Institute for Molecular Plant Physiology and BiophysicsUniversity of WürzburgJulius von‐Sachs Platz 2WürzburgD‐97082Germany
| | - Kai R. Konrad
- Institute for Molecular Plant Physiology and BiophysicsUniversity of WürzburgJulius von‐Sachs Platz 2WürzburgD‐97082Germany
| | - Felix Bemm
- Institute of BioinformaticsCenter for Computational and Theoretical, BiologyUniversity of WürzburgAm HublandWürzburgD‐97218Germany
| | - Meliha Görkem Patir Nebioglu
- Centre for Organismal StudiesDevelopmental Biology of PlantsRuprecht‐Karls‐University of HeidelbergIm Neuenheimer Feld 230Heidelberg69120Germany
| | - Christian Lorey
- Institute for Molecular Plant Physiology and BiophysicsUniversity of WürzburgJulius von‐Sachs Platz 2WürzburgD‐97082Germany
| | - Kerstin Duscha
- Plant PhysiologyUniversity KaiserslauternPostfach 3049KaiserslauternD‐67653Germany
| | - Tilman Güthoff
- Institute for Molecular Plant Physiology and BiophysicsUniversity of WürzburgJulius von‐Sachs Platz 2WürzburgD‐97082Germany
| | - Johannes Herrmann
- Institute for Molecular Plant Physiology and BiophysicsUniversity of WürzburgJulius von‐Sachs Platz 2WürzburgD‐97082Germany
| | - Ali Ferjani
- Department of BiologyTokyo Gakugei UniversityNukui Kitamachi 4‐1‐1Koganei‐shiTokyo184‐8501Japan
| | - Tracey Ann Cuin
- Tasmanian Institute of AgricultureUniversity of TasmaniaHobartTAS7001Australia
| | - M. Rob G. Roelfsema
- Institute for Molecular Plant Physiology and BiophysicsUniversity of WürzburgJulius von‐Sachs Platz 2WürzburgD‐97082Germany
| | - Karin Schumacher
- Centre for Organismal StudiesDevelopmental Biology of PlantsRuprecht‐Karls‐University of HeidelbergIm Neuenheimer Feld 230Heidelberg69120Germany
| | - H. Ekkehard Neuhaus
- Plant PhysiologyUniversity KaiserslauternPostfach 3049KaiserslauternD‐67653Germany
| | - Irene Marten
- Institute for Molecular Plant Physiology and BiophysicsUniversity of WürzburgJulius von‐Sachs Platz 2WürzburgD‐97082Germany
| | - Rainer Hedrich
- Institute for Molecular Plant Physiology and BiophysicsUniversity of WürzburgJulius von‐Sachs Platz 2WürzburgD‐97082Germany
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Faramarzi S, Feng J, Mertz B. Allosteric Effects of the Proton Donor on the Microbial Proton Pump Proteorhodopsin. Biophys J 2018; 115:1240-1250. [PMID: 30219284 DOI: 10.1016/j.bpj.2018.08.028] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 08/21/2018] [Accepted: 08/22/2018] [Indexed: 11/17/2022] Open
Abstract
Proteorhodopsin (PR) is a microbial proton pump that is ubiquitous in marine environments and may play an important role in the oceanic carbon cycle. Photoisomerization of the retinal chromophore in PR leads to a series of proton transfers between specific acidic amino acid residues and the Schiff base of retinal, culminating in a proton motive force to facilitate ATP synthesis. The proton donor in a similar retinal protein, bacteriorhodopsin, acts as a latch to allow the influx of bulk water. However, it is unclear if the proton donor in PR, E108, utilizes the same latch mechanism to become internally hydrated. Here, we used molecular dynamics simulations to model the changes in internal hydration of the blue variant of PR during photoactivation with the proton donor in protonated and deprotonated states. We find that there is a stark contrast in the levels of internal hydration of the cytoplasmic half of PR based on the protonation state of E108. Instead of a latch mechanism, deprotonation of E108 acts as a gate, taking advantage of a nearby polar residue (S61) to promote the formation of a stable water wire from bulk cytoplasm to the retinal-binding pocket over hundreds of nanoseconds. No large-scale conformational changes occur in PR over the microsecond timescale. This subtle yet clear difference in the effect of deprotonation of the proton donor in PR may help explain why the photointermediates that involve the proton donor (i.e., M and N states) have timescales that are orders of magnitude different from the archaeal proton pump, bacteriorhodopsin. In general, our study highlights the importance of understanding how structural fluctuations lead to differences in the way that retinal proteins accomplish the same task.
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Affiliation(s)
- Sadegh Faramarzi
- C. Eugene Department of Chemistry, West Virginia University, Morgantown, West Virginia
| | - Jun Feng
- C. Eugene Department of Chemistry, West Virginia University, Morgantown, West Virginia
| | - Blake Mertz
- C. Eugene Department of Chemistry, West Virginia University, Morgantown, West Virginia.
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Abstract
The majority of human influenza A viruses currently in circulation carry the amantadine-resistant AM2-S31N channel mutation. We previously discovered a series of AM2-S31N inhibitors with potent antiviral activity against both oseltamivir-sensitive and -resistant influenza A viruses. To understand the drug-resistance mechanism of AM2-S31N inhibitors, we performed serial viral passage experiments using the influenza virus A/California/07/2009 (H1N1) to select drug-resistant AM2 mutations against two representative AM2-S31N channel blockers (1 and 2). Unlike amantadine, which gives rise to resistance after a single passage, compounds 1 and 2 selected for partially resistant viruses at passages 05 and 04 with a V27I and L26I mutation, respectively. This appears to suggest compounds 1 and 2 have a higher genetic barrier to resistance than amantadine at least in cell culture. Passage with a higher drug concentration of compound 2 selected higher level resistant viruses with a double mutant L26I + A30T. The mechanism of resistance and replication fitness for mutant viruses were evaluated by electrophysiology, reverse genetics, growth kinetics, and competition assays. AM2-S31N/V27I and AM2-S31N/L26I channels achieved similar specific proton conductance as AM2-S31N, but the AM2-S31N/L26I/A30T triple mutant had drastically reduced specific proton conductance. Viral replication fitness of AM2-S31N/V27I and AM2-S31N/L26I double mutant viruses were similar to AM2-S31N containing viruses in cell culture. However, AM2-S31N/L26I/A30T viruses displayed attenuated growth as well as inability to compete with AM2-S31N viruses. The results herein offer insight regarding the resistance mechanism of AM2-S31N inhibitors, and may help guide the design of the next-generation of AM2-S31N inhibitors with a higher genetic barrier to drug resistance.
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Affiliation(s)
- Rami Musharrafieh
- Department of Chemistry and Biochemistry, The University of Arizona, Tucson, AZ 85721, United States
| | - Chunlong Ma
- BIO5 Institute, The University of Arizona, Tucson, AZ 85721, United States
| | - Jun Wang
- BIO5 Institute, The University of Arizona, Tucson, AZ 85721, United States; Department of Pharmacology and Toxicology, College of Pharmacy, The University of Arizona, Tucson, AZ 85721, United States.
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Abstract
Biochemical and electrophysiological studies on plant vacuolar transporters became feasible in the late 1970s and early 1980s, when methods to isolate large quantities of intact vacuoles and purified vacuolar membrane vesicles were established. However, with the exception of the H+-ATPase and H+-PPase, which could be followed due to their hydrolytic activities, attempts to purify tonoplast transporters were for a long time not successful. Heterologous complementation, T-DNA insertion mutants, and later proteomic studies allowed the next steps, starting from the 1990s. Nowadays, our knowledge about vacuolar transporters has increased greatly. Nevertheless, there are several transporters of central importance that have still to be identified at the molecular level or have even not been characterized biochemically. Furthermore, our knowledge about regulation of the vacuolar transporters is very limited, and much work is needed to get a holistic view about the interplay of the vacuolar transportome. The huge amount of information generated during the last 35 years cannot be summarized in such a review. Therefore, I decided to concentrate on some aspects where we were involved during my research on vacuolar transporters, for some our laboratories contributed more, while others contributed less.
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Affiliation(s)
- Enrico Martinoia
- Department of Plant and Microbial Biology, University of Zurich, 8008 Zurich, Switzerland
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