1
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De Vecchis D, Schäfer LV. Coupling the role of lipids to the conformational dynamics of the ABC transporter P-glycoprotein. Biophys J 2024:S0006-3495(24)00417-X. [PMID: 38909280 DOI: 10.1016/j.bpj.2024.06.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2024] [Revised: 05/31/2024] [Accepted: 06/18/2024] [Indexed: 06/24/2024] Open
Abstract
The ATP-binding cassette transporter P-glycoprotein (P-gp) is a multidrug efflux pump that is overexpressed in a variety of cancers and associated with the drug-resistance phenomenon. P-gp structures were previously determined in detergent and in nanodiscs, in which different transmembrane helix conformations were found, "straight" and "kinked," respectively, indicating a possible role of the lipid environment on the P-gp structural ensemble. Here, we investigate the dynamic conformational ensembles and protein-lipid interactions of two human P-gp inward-open conformers, straight and kinked, employing all-atom molecular dynamics (MD) simulations in asymmetric multicomponent lipid bilayers that mimic the highly specialized hepatocyte membrane in which P-gp is expressed. The two conformers are found to differ in terms of the accessibility of the substrate cavity. The MD simulations show how cholesterol and different lipid species wedge, snorkel, and partially enter into the cavity of the straight P-gp conformer solved in detergent. However, access to the cavity of the kinked P-gp conformer solved in nanodiscs is restricted. Furthermore, the volume and dynamic fluctuations of the substrate cavity largely differ between the two P-gp conformers and are modulated by the presence (or absence) of cholesterol in the membrane and/or of ATP. From the mechanistic perspective, the findings indicate that the straight conformer likely precedes the kinked conformer in the functional working cycle of P-gp, with the latter conformation representing a post substrate-bound state. The inaccessibility of the main transmembrane cavity in the kinked conformer might be crucial in preventing substrate disengagement and transport withdrawal. Remarkably, in our unbiased MD simulations, one transmembrane helix (TM10) of the straight conformer underwent a spontaneous transition to a kinked conformation, underlining the relevance of both conformations in a native phospholipid environment and revealing structural descriptors defining the transition between the two P-gp conformers.
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Affiliation(s)
- Dario De Vecchis
- Center for Theoretical Chemistry, Ruhr University Bochum, Bochum, Germany.
| | - Lars V Schäfer
- Center for Theoretical Chemistry, Ruhr University Bochum, Bochum, Germany.
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2
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Zhao CR, You ZL, Bai L. Fungal Plasma Membrane H +-ATPase: Structure, Mechanism, and Drug Discovery. J Fungi (Basel) 2024; 10:273. [PMID: 38667944 PMCID: PMC11051447 DOI: 10.3390/jof10040273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 04/01/2024] [Accepted: 04/02/2024] [Indexed: 04/28/2024] Open
Abstract
The fungal plasma membrane H+-ATPase (Pma1) pumps protons out of the cell to maintain the transmembrane electrochemical gradient and membrane potential. As an essential P-type ATPase uniquely found in fungi and plants, Pma1 is an attractive antifungal drug target. Two recent Cryo-EM studies on Pma1 have revealed its hexameric architecture, autoinhibitory and activation mechanisms, and proton transport mechanism. These structures provide new perspectives for the development of antifungal drugs targeting Pma1. In this article, we review the history of Pma1 structure determination, the latest structural insights into Pma1, and drug discoveries targeting Pma1.
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Affiliation(s)
- Chao-Ran Zhao
- Department of Otolaryngology Head and Neck Surgery, Beijing Tongren Hospital, Capital Medical University, Beijing 100730, China
- Beijing Key Laboratory of Nasal Diseases, Beijing Institute of Otolaryngology, Beijing 100005, China
| | - Zi-Long You
- Department of Biophysics, School of Basic Medical Sciences, Peking University, Beijing 100083, China
| | - Lin Bai
- Department of Biophysics, School of Basic Medical Sciences, Peking University, Beijing 100083, China
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3
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Young MR, Heit S, Bublitz M. Structure, function and biogenesis of the fungal proton pump Pma1. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 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] [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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4
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Sun Q, Zhao D, Gao M, Wu Y, Zhai L, Sun S, Wu T, Zhang X, Xu X, Han Z, Wang Y. MxMPK6-2-mediated phosphorylation enhances the response of apple rootstocks to Fe deficiency by activating PM H + -ATPase MxHA2. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2023; 116:69-86. [PMID: 37340905 DOI: 10.1111/tpj.16360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 06/12/2023] [Accepted: 06/16/2023] [Indexed: 06/22/2023]
Abstract
Iron (Fe) deficiency significantly affects the growth and development, fruit yield and quality of apples. Apple roots respond to Fe deficiency stress by promoting H+ secretion, which acidifies the soil. In this study, the plasma membrane (PM) H+ -ATPase MxHA2 promoted H+ secretion and root acidification of apple rootstocks under Fe deficiency stress. H+ -ATPase MxHA2 is upregulated in Fe-efficient apple rootstock of Malus xiaojinensis at the transcription level. Fe deficiency also induced kinase MxMPK6-2, a positive regulator in Fe absorption that can interact with MxHA2. However, the mechanism involving these two factors under Fe deficiency stress is unclear. MxMPK6-2 overexpression in apple roots positively regulated PM H+ -ATPase activity, thus enhancing root acidification under Fe deficiency stress. Moreover, co-expression of MxMPK6-2 and MxHA2 in apple rootstocks further enhanced PM H+ -ATPase activity under Fe deficiency. MxMPK6-2 phosphorylated MxHA2 at the Ser909 site of C terminus, Thr320 and Thr412 sites of the Central loop region. Phosphorylation at the Ser909 and Thr320 promoted PM H+ -ATPase activity, while phosphorylation at Thr412 inhibited PM H+ -ATPase activity. MxMPK6-2 also phosphorylated the Fe deficiency-induced transcription factor MxbHLH104 at the Ser169 site, which then could bind to the promoter of MxHA2, thus enhancing MxHA2 upregulation. In conclusion, the MAP kinase MxMPK6-2-mediated phosphorylation directly and indirectly regulates PM H+ -ATPase MxHA2 activity at the protein post-translation and transcription levels, thus synergistically enhancing root acidification under Fe deficiency stress.
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Affiliation(s)
- Qiran Sun
- College of Horticulture, China Agricultural University, Beijing, 100193, People's Republic of China
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (Nutrition and Physiology), Ministry of Agriculture and Rural Affairs, Beijing, 100193, People's Republic of China
| | - Danrui Zhao
- College of Horticulture, China Agricultural University, Beijing, 100193, People's Republic of China
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (Nutrition and Physiology), Ministry of Agriculture and Rural Affairs, Beijing, 100193, People's Republic of China
| | - Min Gao
- College of Horticulture, China Agricultural University, Beijing, 100193, People's Republic of China
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (Nutrition and Physiology), Ministry of Agriculture and Rural Affairs, Beijing, 100193, People's Republic of China
| | - Yue Wu
- College of Horticulture, China Agricultural University, Beijing, 100193, People's Republic of China
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (Nutrition and Physiology), Ministry of Agriculture and Rural Affairs, Beijing, 100193, People's Republic of China
| | - Longmei Zhai
- College of Horticulture, China Agricultural University, Beijing, 100193, People's Republic of China
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (Nutrition and Physiology), Ministry of Agriculture and Rural Affairs, Beijing, 100193, People's Republic of China
| | - Shan Sun
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structure, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, People's Republic of China
| | - Ting Wu
- College of Horticulture, China Agricultural University, Beijing, 100193, People's Republic of China
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (Nutrition and Physiology), Ministry of Agriculture and Rural Affairs, Beijing, 100193, People's Republic of China
| | - Xinzhong Zhang
- College of Horticulture, China Agricultural University, Beijing, 100193, People's Republic of China
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (Nutrition and Physiology), Ministry of Agriculture and Rural Affairs, Beijing, 100193, People's Republic of China
| | - Xuefeng Xu
- College of Horticulture, China Agricultural University, Beijing, 100193, People's Republic of China
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (Nutrition and Physiology), Ministry of Agriculture and Rural Affairs, Beijing, 100193, People's Republic of China
| | - Zhenhai Han
- College of Horticulture, China Agricultural University, Beijing, 100193, People's Republic of China
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (Nutrition and Physiology), Ministry of Agriculture and Rural Affairs, Beijing, 100193, People's Republic of China
| | - Yi Wang
- College of Horticulture, China Agricultural University, Beijing, 100193, People's Republic of China
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (Nutrition and Physiology), Ministry of Agriculture and Rural Affairs, Beijing, 100193, People's Republic of China
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5
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Paweletz LC, Holtbrügge SL, Löb M, De Vecchis D, Schäfer LV, Günther Pomorski T, Justesen BH. Anionic Phospholipids Stimulate the Proton Pumping Activity of the Plant Plasma Membrane P-Type H +-ATPase. Int J Mol Sci 2023; 24:13106. [PMID: 37685912 PMCID: PMC10488199 DOI: 10.3390/ijms241713106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 08/16/2023] [Accepted: 08/18/2023] [Indexed: 09/10/2023] Open
Abstract
The activity of membrane proteins depends strongly on the surrounding lipid environment. Here, we characterize the lipid stimulation of the plant plasma membrane H+-ATPase Arabidopsis thaliana H+-ATPase isoform 2 (AHA2) upon purification and reconstitution into liposomes of defined lipid compositions. We show that the proton pumping activity of AHA2 is stimulated by anionic phospholipids, especially by phosphatidylserine. This activation was independent of the cytoplasmic C-terminal regulatory domain of the pump. Molecular dynamics simulations revealed several preferential contact sites for anionic phospholipids in the transmembrane domain of AHA2. These contact sites are partially conserved in functionally different P-type ATPases from different organisms, suggesting a general regulation mechanism by the membrane lipid environment. Our findings highlight the fact that anionic lipids play an important role in the control of H+-ATPase activity.
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Affiliation(s)
- Laura C. Paweletz
- Department of Molecular Biochemistry, Faculty of Chemistry and Biochemistry, Ruhr University Bochum, 44780 Bochum, Germany; (L.C.P.); (M.L.); (T.G.P.)
| | - Simon L. Holtbrügge
- Center for Theoretical Chemistry, Faculty of Chemistry and Biochemistry, Ruhr University Bochum, 44780 Bochum, Germany; (S.L.H.); (D.D.V.)
| | - Malina Löb
- Department of Molecular Biochemistry, Faculty of Chemistry and Biochemistry, Ruhr University Bochum, 44780 Bochum, Germany; (L.C.P.); (M.L.); (T.G.P.)
| | - Dario De Vecchis
- Center for Theoretical Chemistry, Faculty of Chemistry and Biochemistry, Ruhr University Bochum, 44780 Bochum, Germany; (S.L.H.); (D.D.V.)
| | - Lars V. Schäfer
- Center for Theoretical Chemistry, Faculty of Chemistry and Biochemistry, Ruhr University Bochum, 44780 Bochum, Germany; (S.L.H.); (D.D.V.)
| | - Thomas Günther Pomorski
- Department of Molecular Biochemistry, Faculty of Chemistry and Biochemistry, Ruhr University Bochum, 44780 Bochum, Germany; (L.C.P.); (M.L.); (T.G.P.)
- Department of Plant and Environmental Sciences, University of Copenhagen, 1871 Frederiksberg C, Denmark
| | - Bo Højen Justesen
- Department of Molecular Biochemistry, Faculty of Chemistry and Biochemistry, Ruhr University Bochum, 44780 Bochum, Germany; (L.C.P.); (M.L.); (T.G.P.)
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6
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Andersen CG, Bavnhøj L, Pedersen BP. May the proton motive force be with you: A plant transporter review. Curr Opin Struct Biol 2023; 79:102535. [PMID: 36796226 DOI: 10.1016/j.sbi.2023.102535] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 11/28/2022] [Accepted: 01/03/2023] [Indexed: 02/16/2023]
Abstract
As our ecosystems experience challenges associated with climate change, an improved understanding of the fundamental biochemical processes governing plant physiology is needed. Strikingly, current structural information on plant membrane transporters is severely limited compared to other kingdoms of life, with only 18 unique structures in total. To advance future breakthroughs and insight in plant cell molecular biology, structural knowledge of membrane transporters is indispensable. This review summarizes the current status of structural knowledge in the plant membrane transporter field. Plants utilize the proton motive force (PMF) to drive secondary active transport. We discuss the PMF, how it relates to secondary active transport and provide a classification of PMF driven secondary active transport, discussing recently published structures of symporters, antiporters, and uniporters from plants.
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Affiliation(s)
| | - Laust Bavnhøj
- Department of Molecular Biology and Genetics, Aarhus University, 8000, Aarhus C, Denmark. https://twitter.com/laustbavnhoej
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7
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Structural and Functional Diversity of Two ATP-Driven Plant Proton Pumps. Int J Mol Sci 2023; 24:ijms24054512. [PMID: 36901943 PMCID: PMC10003446 DOI: 10.3390/ijms24054512] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 02/09/2023] [Accepted: 02/22/2023] [Indexed: 03/02/2023] Open
Abstract
Two ATP-dependent proton pumps function in plant cells. Plasma membrane H+-ATPase (PM H+-ATPase) transfers protons from the cytoplasm to the apoplast, while vacuolar H+-ATPase (V-ATPase), located in tonoplasts and other endomembranes, is responsible for proton pumping into the organelle lumen. Both enzymes belong to two different families of proteins and, therefore, differ significantly in their structure and mechanism of action. The plasma membrane H+-ATPase is a member of the P-ATPases that undergo conformational changes, associated with two distinct E1 and E2 states, and autophosphorylation during the catalytic cycle. The vacuolar H+-ATPase represents rotary enzymes functioning as a molecular motor. The plant V-ATPase consists of thirteen different subunits organized into two subcomplexes, the peripheral V1 and the membrane-embedded V0, in which the stator and rotor parts have been distinguished. In contrast, the plant plasma membrane proton pump is a functional single polypeptide chain. However, when the enzyme is active, it transforms into a large twelve-protein complex of six H+-ATPase molecules and six 14-3-3 proteins. Despite these differences, both proton pumps can be regulated by the same mechanisms (such as reversible phosphorylation) and, in some processes, such as cytosolic pH regulation, may act in a coordinated way.
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8
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Roterman I, Stapor K, Fabian P, Konieczny L. Connexins and Pannexins—Similarities and Differences According to the FOD-M Model. Biomedicines 2022; 10:biomedicines10071504. [PMID: 35884807 PMCID: PMC9313468 DOI: 10.3390/biomedicines10071504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 06/19/2022] [Accepted: 06/24/2022] [Indexed: 11/26/2022] Open
Abstract
Connexins and pannexins are the transmembrane proteins of highly distinguished biological activity in the form of transport of molecules and electrical signals. Their common role is to connect the external environment with the cytoplasm of the cell, while connexin is also able to link two cells together allowing the transport from one to another. The analysis presented here aims to identify the similarities and differences between connexin and pannexin. As a comparative criterion, the hydrophobicity distribution in the structure of the discussed proteins was used. The comparative analysis is carried out with the use of a mathematical model, the FOD-M model (fuzzy oil drop model in its Modified version) expressing the specificity of the membrane’s external field, which in the case of the discussed proteins is significantly different from the external field for globular proteins in the polar environment of water. The characteristics of the external force field influence the structure of protein allowing the activity in a different environment.
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Affiliation(s)
- Irena Roterman
- Department of Bioinformatics and Telemedicine, Jagiellonian University—Medical College, Medyczna 7, 30-688 Kraków, Poland
- Correspondence:
| | - Katarzyna Stapor
- Department of Applied Informatics, Faculty of Automatic, Electronics and Computer Science, Silesian University of Technology, Akademicka 16, 44-100 Gliwice, Poland;
| | - Piotr Fabian
- Department of Algorithmics and Software, Faculty of Automatic, Electronics and Computer Science, Silesian University of Technology, Akademicka 16, 44-100 Gliwice, Poland;
| | - Leszek Konieczny
- Chair of Medical Biochemistry—Jagiellonian University—Medical College, Kopernika 7, 31-034 Kraków, Poland;
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9
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Bondar AN. Mechanisms of long-distance allosteric couplings in proton-binding membrane transporters. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2022; 128:199-239. [PMID: 35034719 DOI: 10.1016/bs.apcsb.2021.09.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Membrane transporters that use proton binding and proton transfer for function couple local protonation change with changes in protein conformation and water dynamics. Changes of protein conformation might be required to allow transient formation of hydrogen-bond networks that bridge proton donor and acceptor pairs separated by long distances. Inter-helical hydrogen-bond networks adjust rapidly to protonation change, and ensure rapid response of the protein structure and dynamics. Membrane transporters with known three-dimensional structures and proton-binding groups inform on general principles of protonation-coupled protein conformational dynamics. Inter-helical hydrogen bond motifs between proton-binding carboxylate groups and a polar sidechain are observed in unrelated membrane transporters, suggesting common principles of coupling protonation change with protein conformational dynamics.
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Affiliation(s)
- Ana-Nicoleta Bondar
- University of Bucharest, Faculty of Physics, Măgurele, Romania; Forschungszentrum Jülich, Institute of Computational Biomedicine, Jülich, Germany.
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10
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Lanrezac A, Férey N, Baaden M. Wielding the power of interactive molecular simulations. WIRES COMPUTATIONAL MOLECULAR SCIENCE 2021. [DOI: 10.1002/wcms.1594] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- André Lanrezac
- CNRS, Laboratoire de Biochimie Théorique Université de Paris Paris France
| | - Nicolas Férey
- CNRS, Laboratoire interdisciplinaire des sciences du numérique Université Paris‐Saclay Orsay France
| | - Marc Baaden
- CNRS, Laboratoire de Biochimie Théorique Université de Paris Paris France
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11
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Heit S, Geurts MMG, Murphy BJ, Corey RA, Mills DJ, Kühlbrandt W, Bublitz M. Structure of the hexameric fungal plasma membrane proton pump in its autoinhibited state. SCIENCE ADVANCES 2021; 7:eabj5255. [PMID: 34757782 DOI: 10.1101/2021.04.30.442159] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The fungal plasma membrane H+-ATPase Pma1 is a vital enzyme, generating a proton-motive force that drives the import of essential nutrients. Autoinhibited Pma1 hexamers in the plasma membrane of starving fungi are activated by glucose signaling and subsequent phosphorylation of the autoinhibitory domain. As related P-type adenosine triphosphatases (ATPases) are not known to oligomerize, the physiological relevance of Pma1 hexamers remained unknown. We have determined the structure of hexameric Pma1 from Neurospora crassa by electron cryo-microscopy at 3.3-Å resolution, elucidating the molecular basis for hexamer formation and autoinhibition and providing a basis for structure-based drug development. Coarse-grained molecular dynamics simulations in a lipid bilayer suggest lipid-mediated contacts between monomers and a substantial protein-induced membrane deformation that could act as a proton-attracting funnel.
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Affiliation(s)
- Sabine Heit
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Maxwell M G Geurts
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Bonnie J Murphy
- Max Planck Institute of Biophysics, Max-von-Laue-Str.3, 60438 Frankfurt am Main, Germany
| | - Robin A Corey
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Deryck J Mills
- Max Planck Institute of Biophysics, Max-von-Laue-Str.3, 60438 Frankfurt am Main, Germany
| | - Werner Kühlbrandt
- Max Planck Institute of Biophysics, Max-von-Laue-Str.3, 60438 Frankfurt am Main, Germany
| | - Maike Bublitz
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
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12
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Heit S, Geurts MMG, Murphy BJ, Corey RA, Mills DJ, Kühlbrandt W, Bublitz M. Structure of the hexameric fungal plasma membrane proton pump in its autoinhibited state. SCIENCE ADVANCES 2021; 7:eabj5255. [PMID: 34757782 PMCID: PMC8580308 DOI: 10.1126/sciadv.abj5255] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Accepted: 09/22/2021] [Indexed: 05/11/2023]
Abstract
The fungal plasma membrane H+-ATPase Pma1 is a vital enzyme, generating a proton-motive force that drives the import of essential nutrients. Autoinhibited Pma1 hexamers in the plasma membrane of starving fungi are activated by glucose signaling and subsequent phosphorylation of the autoinhibitory domain. As related P-type adenosine triphosphatases (ATPases) are not known to oligomerize, the physiological relevance of Pma1 hexamers remained unknown. We have determined the structure of hexameric Pma1 from Neurospora crassa by electron cryo-microscopy at 3.3-Å resolution, elucidating the molecular basis for hexamer formation and autoinhibition and providing a basis for structure-based drug development. Coarse-grained molecular dynamics simulations in a lipid bilayer suggest lipid-mediated contacts between monomers and a substantial protein-induced membrane deformation that could act as a proton-attracting funnel.
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Affiliation(s)
- Sabine Heit
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Maxwell M. G. Geurts
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Bonnie J. Murphy
- Max Planck Institute of Biophysics, Max-von-Laue-Str.3, 60438 Frankfurt am Main, Germany
| | - Robin A. Corey
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Deryck J. Mills
- Max Planck Institute of Biophysics, Max-von-Laue-Str.3, 60438 Frankfurt am Main, Germany
| | - Werner Kühlbrandt
- Max Planck Institute of Biophysics, Max-von-Laue-Str.3, 60438 Frankfurt am Main, Germany
| | - Maike Bublitz
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
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13
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Zhao P, Zhao C, Chen D, Yun C, Li H, Bai L. Structure and activation mechanism of the hexameric plasma membrane H +-ATPase. Nat Commun 2021; 12:6439. [PMID: 34750373 PMCID: PMC8575881 DOI: 10.1038/s41467-021-26782-y] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2021] [Accepted: 10/22/2021] [Indexed: 11/29/2022] Open
Abstract
The S. cerevisiae plasma membrane H+-ATPase, Pma1, is a P3A-type ATPase and the primary protein component of the membrane compartment of Pma1 (MCP). Like other plasma membrane H+-ATPases, Pma1 assembles and functions as a hexamer, a property unique to this subfamily among the larger family of P-type ATPases. It has been unclear how Pma1 organizes the yeast membrane into MCP microdomains, or why it is that Pma1 needs to assemble into a hexamer to establish the membrane electrochemical proton gradient. Here we report a high-resolution cryo-EM study of native Pma1 hexamers embedded in endogenous lipids. Remarkably, we found that the Pma1 hexamer encircles a liquid-crystalline membrane domain composed of 57 ordered lipid molecules. The Pma1-encircled lipid patch structure likely serves as the building block of the MCP. At pH 7.4, the carboxyl-terminal regulatory α-helix binds to the phosphorylation domains of two neighboring Pma1 subunits, locking the hexamer in the autoinhibited state. The regulatory helix becomes disordered at lower pH, leading to activation of the Pma1 hexamer. The activation process is accompanied by a 6.7 Å downward shift and a 40° rotation of transmembrane helices 1 and 2 that line the proton translocation path. The conformational changes have enabled us to propose a detailed mechanism for ATP-hydrolysis-driven proton pumping across the plasma membrane. Our structures will facilitate the development of antifungal drugs that target this essential protein.
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Affiliation(s)
- Peng Zhao
- Department of Biochemistry and Biophysics, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Chaoran Zhao
- Department of Biochemistry and Biophysics, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Dandan Chen
- Department of Biochemistry and Biophysics, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Caihong Yun
- Department of Biochemistry and Biophysics, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Huilin Li
- Department of Structural Biology, Van Andel Institute, Grand Rapids, MI, USA.
| | - Lin Bai
- Department of Biochemistry and Biophysics, School of Basic Medical Sciences, Peking University, Beijing, China.
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14
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Zhang Y, Watanabe S, Tsutsumi A, Kadokura H, Kikkawa M, Inaba K. Cryo-EM analysis provides new mechanistic insight into ATP binding to Ca 2+ -ATPase SERCA2b. EMBO J 2021; 40:e108482. [PMID: 34459010 DOI: 10.15252/embj.2021108482] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 08/02/2021] [Accepted: 08/04/2021] [Indexed: 12/31/2022] Open
Abstract
Sarco/endoplasmic reticulum Ca2+ -ATPase (SERCA) 2b is a ubiquitous SERCA family member that conducts Ca2+ uptake from the cytosol to the ER. Herein, we present a 3.3 Å resolution cryo-electron microscopy (cryo-EM) structure of human SERCA2b in the E1·2Ca2+ state, revealing a new conformation for Ca2+ -bound SERCA2b with a much closer arrangement of cytosolic domains than in the previously reported crystal structure of Ca2+ -bound SERCA1a. Multiple conformations generated by 3D classification of cryo-EM maps reflect the intrinsically dynamic nature of the cytosolic domains in this state. Notably, ATP binding residues of SERCA2b in the E1·2Ca2+ state are located at similar positions to those in the E1·2Ca2+ -ATP state; hence, the cryo-EM structure likely represents a preformed state immediately prior to ATP binding. Consistently, a SERCA2b mutant with an interdomain disulfide bridge that locks the closed cytosolic domain arrangement displayed significant autophosphorylation activity in the presence of Ca2+ . We propose a novel mechanism of ATP binding to SERCA2b.
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Affiliation(s)
- Yuxia Zhang
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai, Japan
| | - Satoshi Watanabe
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai, Japan
| | - Akihisa Tsutsumi
- Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Hiroshi Kadokura
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai, Japan
| | - Masahide Kikkawa
- Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Kenji Inaba
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai, Japan
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15
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Bondar AN. Proton-Binding Motifs of Membrane-Bound Proteins: From Bacteriorhodopsin to Spike Protein S. Front Chem 2021; 9:685761. [PMID: 34136464 PMCID: PMC8203321 DOI: 10.3389/fchem.2021.685761] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 05/18/2021] [Indexed: 11/13/2022] Open
Abstract
Membrane-bound proteins that change protonation during function use specific protein groups to bind and transfer protons. Knowledge of the identity of the proton-binding groups is of paramount importance to decipher the reaction mechanism of the protein, and protonation states of prominent are studied extensively using experimental and computational approaches. Analyses of model transporters and receptors from different organisms, and with widely different biological functions, indicate common structure-sequence motifs at internal proton-binding sites. Proton-binding dynamic hydrogen-bond networks that are exposed to the bulk might provide alternative proton-binding sites and proton-binding pathways. In this perspective article I discuss protonation coupling and proton binding at internal and external carboxylate sites of proteins that use proton transfer for function. An inter-helical carboxylate-hydroxyl hydrogen-bond motif is present at functionally important sites of membrane proteins from archaea to the brain. External carboxylate-containing H-bond clusters are observed at putative proton-binding sites of protonation-coupled model proteins, raising the question of similar functionality in spike protein S.
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Affiliation(s)
- Ana-Nicoleta Bondar
- Freie Universität Berlin, Department of Physics, Theoretical Molecular Biophysics Group, Berlin, Germany
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16
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Hansen SB, Dyla M, Neumann C, Quistgaard EMH, Andersen JL, Kjaergaard M, Nissen P. The Crystal Structure of the Ca 2+-ATPase 1 from Listeria monocytogenes reveals a Pump Primed for Dephosphorylation. J Mol Biol 2021; 433:167015. [PMID: 33933469 DOI: 10.1016/j.jmb.2021.167015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 04/19/2021] [Accepted: 04/22/2021] [Indexed: 12/18/2022]
Abstract
Many bacteria export intracellular calcium using active transporters homologous to the sarco/endoplasmic reticulum Ca2+-ATPase (SERCA). Here we present three crystal structures of Ca2+-ATPase 1 from Listeria monocytogenes (LMCA1). Structures with BeF3- mimicking a phosphoenzyme state reveal a closed state, which is intermediate between the outward-open E2P and the proton-occluded E2-P* conformations known for SERCA. It suggests that LMCA1 in the E2P state is pre-organized for dephosphorylation upon Ca2+ release, consistent with the rapid dephosphorylation observed in single-molecule studies. An arginine side-chain occupies the position equivalent to calcium binding site I in SERCA, leaving a single Ca2+ binding site in LMCA1, corresponding to SERCA site II. Observing no putative transport pathways dedicated to protons, we infer a direct proton counter transport through the Ca2+ exchange pathways. The LMCA1 structures provide insight into the evolutionary divergence and conserved features of this important class of ion transporters.
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Affiliation(s)
- Sara Basse Hansen
- Department of Molecular Biology and Genetics, Aarhus University, Denmark; The Danish Research Institute for Translational Neuroscience (DANDRITE), Nordic EMBL Partnership for Molecular Medicine, Denmark
| | - Mateusz Dyla
- Department of Molecular Biology and Genetics, Aarhus University, Denmark; The Danish Research Institute for Translational Neuroscience (DANDRITE), Nordic EMBL Partnership for Molecular Medicine, Denmark
| | - Caroline Neumann
- Department of Molecular Biology and Genetics, Aarhus University, Denmark; The Danish Research Institute for Translational Neuroscience (DANDRITE), Nordic EMBL Partnership for Molecular Medicine, Denmark
| | - Esben Meldgaard Hoegh Quistgaard
- Department of Molecular Biology and Genetics, Aarhus University, Denmark; The Danish Research Institute for Translational Neuroscience (DANDRITE), Nordic EMBL Partnership for Molecular Medicine, Denmark
| | - Jacob Lauwring Andersen
- Department of Molecular Biology and Genetics, Aarhus University, Denmark; The Danish Research Institute for Translational Neuroscience (DANDRITE), Nordic EMBL Partnership for Molecular Medicine, Denmark
| | - Magnus Kjaergaard
- Department of Molecular Biology and Genetics, Aarhus University, Denmark; The Danish Research Institute for Translational Neuroscience (DANDRITE), Nordic EMBL Partnership for Molecular Medicine, Denmark; Aarhus Institute of Advanced Studies (AIAS), Denmark; The Danish National Research Foundation Center for Proteins in Memory (PROMEMO), Denmark
| | - Poul Nissen
- Department of Molecular Biology and Genetics, Aarhus University, Denmark; The Danish Research Institute for Translational Neuroscience (DANDRITE), Nordic EMBL Partnership for Molecular Medicine, Denmark; The Danish National Research Foundation Center for Proteins in Memory (PROMEMO), Denmark.
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17
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A conserved, buried cysteine near the P-site is accessible to cysteine modifications and increases ROS stability in the P-type plasma membrane H+-ATPase. Biochem J 2021; 478:619-632. [DOI: 10.1042/bcj20200559] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 12/16/2020] [Accepted: 01/08/2021] [Indexed: 02/06/2023]
Abstract
Sulfur-containing amino acid residues function in antioxidative responses, which can be induced by the reactive oxygen species generated by excessive copper and hydrogen peroxide. In all Na+/K+, Ca2+, and H+ pumping P-type ATPases, a cysteine residue is present two residues upstream of the essential aspartate residue, which is obligatorily phosphorylated in each catalytic cycle. Despite its conservation, the function of this cysteine residue was hitherto unknown. In this study, we analyzed the function of the corresponding cysteine residue (Cys-327) in the autoinhibited plasma membrane H+-ATPase isoform 2 (AHA2) from Arabidopsis thaliana by mutagenesis and heterologous expression in a yeast host. Enzyme kinetics of alanine, serine, and leucine substitutions were identical with those of the wild-type pump but the sensitivity of the mutant pumps was increased towards copper and hydrogen peroxide. Peptide identification and sequencing by mass spectrometry demonstrated that Cys-327 was prone to oxidation. These data suggest that Cys-327 functions as a protective residue in the plasma membrane H+-ATPase, and possibly in other P-type ATPases as well.
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18
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Cosse M, Seidel T. Plant Proton Pumps and Cytosolic pH-Homeostasis. FRONTIERS IN PLANT SCIENCE 2021; 12:672873. [PMID: 34177988 PMCID: PMC8220075 DOI: 10.3389/fpls.2021.672873] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 04/15/2021] [Indexed: 05/06/2023]
Abstract
Proton pumps create a proton motif force and thus, energize secondary active transport at the plasma nmembrane and endomembranes of the secretory pathway. In the plant cell, the dominant proton pumps are the plasma membrane ATPase, the vacuolar pyrophosphatase (V-PPase), and the vacuolar-type ATPase (V-ATPase). All these pumps act on the cytosolic pH by pumping protons into the lumen of compartments or into the apoplast. To maintain the typical pH and thus, the functionality of the cytosol, the activity of the pumps needs to be coordinated and adjusted to the actual needs. The cellular toolbox for a coordinated regulation comprises 14-3-3 proteins, phosphorylation events, ion concentrations, and redox-conditions. This review combines the knowledge on regulation of the different proton pumps and highlights possible coordination mechanisms.
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19
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Channelrhodopsin-mediated optogenetics highlights a central role of depolarization-dependent plant proton pumps. Proc Natl Acad Sci U S A 2020; 117:20920-20925. [PMID: 32788371 PMCID: PMC7456130 DOI: 10.1073/pnas.2005626117] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
People for centuries are puzzled how living creatures like plants sense their environment. Plants employ electrical signals to communicate a cue-dependent local status between plants cells and organs. As a first response to biotic and abiotic stresses, the membrane potential of plant cells depolarizes. Recovery from the depolarized state, repolarization, was proposed to involve ion channels and pumps. Here, we established channelrhodopsin (ChR2)-based optogenetics in plants and learned that the plant plasma membrane H+-ATPase represents the major driver of membrane potential repolarization control during plant electrical signaling, rather than voltage-dependent ion channels. In plants, environmental stressors trigger plasma membrane depolarizations. Being electrically interconnected via plasmodesmata, proper functional dissection of electrical signaling by electrophysiology is basically impossible. The green alga Chlamydomonas reinhardtii evolved blue light-excited channelrhodopsins (ChR1, 2) to navigate. When expressed in excitable nerve and muscle cells, ChRs can be used to control the membrane potential via illumination. In Arabidopsis plants, we used the algal ChR2-light switches as tools to stimulate plasmodesmata-interconnected photosynthetic cell networks by blue light and monitor the subsequent plasma membrane electrical responses. Blue-dependent stimulations of ChR2 expressing mesophyll cells, resting around −160 to −180 mV, reproducibly depolarized the membrane potential by 95 mV on average. Following excitation, mesophyll cells recovered their prestimulus potential not without transiently passing a hyperpolarization state. By combining optogenetics with voltage-sensing microelectrodes, we demonstrate that plant plasma membrane AHA-type H+-ATPase governs the gross repolarization process. AHA2 protein biochemistry and functional expression analysis in Xenopus oocytes indicates that the capacity of this H+ pump to recharge the membrane potential is rooted in its voltage- and pH-dependent functional anatomy. Thus, ChR2 optogenetics appears well suited to noninvasively expose plant cells to signal specific depolarization signatures. From the responses we learn about the molecular processes, plants employ to channel stress-associated membrane excitations into physiological responses.
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20
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Sitsel A, De Raeymaecker J, Drachmann ND, Derua R, Smaardijk S, Andersen JL, Vandecaetsbeek I, Chen J, De Maeyer M, Waelkens E, Olesen C, Vangheluwe P, Nissen P. Structures of the heart specific SERCA2a Ca 2+-ATPase. EMBO J 2019; 38:embj.2018100020. [PMID: 30777856 DOI: 10.15252/embj.2018100020] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2018] [Revised: 12/29/2018] [Accepted: 01/10/2019] [Indexed: 12/11/2022] Open
Abstract
The sarcoplasmic/endoplasmic reticulum Ca2+-ATPase 2a (SERCA2a) performs active reuptake of cytoplasmic Ca2+ and is a major regulator of cardiac muscle contractility. Dysfunction or dysregulation of SERCA2a is associated with heart failure, while restoring its function is considered as a therapeutic strategy to restore cardiac performance. However, its structure has not yet been determined. Based on native, active protein purified from pig ventricular muscle, we present the first crystal structures of SERCA2a, determined in the CPA-stabilized E2-AlF4- form (3.3 Å) and the Ca2+-occluded [Ca2]E1-AMPPCP form (4.0 Å). The structures are similar to the skeletal muscle isoform SERCA1a pointing to a conserved mechanism. We seek to explain the kinetic differences between SERCA1a and SERCA2a. We find that several isoform-specific residues are acceptor sites for post-translational modifications. In addition, molecular dynamics simulations predict that isoform-specific residues support distinct intramolecular interactions in SERCA2a and SERCA1a. Our experimental observations further indicate that isoform-specific intramolecular interactions are functionally relevant, and may explain the kinetic differences between SERCA2a and SERCA1a.
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Affiliation(s)
- Aljona Sitsel
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark.,Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium.,Center for Membrane Proteins in Cells and Disease - PUMPkin, Danish National Research Foundation, Aarhus C, Denmark.,Danish Research Institute of Translational Neuroscience - DANDRITE, Nordic-EMBL Partnership for Molecular Medicine, Aarhus C, Denmark
| | | | - Nikolaj Düring Drachmann
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark.,Center for Membrane Proteins in Cells and Disease - PUMPkin, Danish National Research Foundation, Aarhus C, Denmark
| | - Rita Derua
- Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium.,SyBioMa, KU Leuven, Leuven, Belgium
| | - Susanne Smaardijk
- Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Jacob Lauwring Andersen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark.,Center for Membrane Proteins in Cells and Disease - PUMPkin, Danish National Research Foundation, Aarhus C, Denmark.,Department of Biomedicine, Aarhus University, Aarhus C, Denmark
| | | | - Jialin Chen
- Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | | | - Etienne Waelkens
- Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium.,SyBioMa, KU Leuven, Leuven, Belgium
| | - Claus Olesen
- Center for Membrane Proteins in Cells and Disease - PUMPkin, Danish National Research Foundation, Aarhus C, Denmark .,Department of Biomedicine, Aarhus University, Aarhus C, Denmark
| | - Peter Vangheluwe
- Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Poul Nissen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark .,Center for Membrane Proteins in Cells and Disease - PUMPkin, Danish National Research Foundation, Aarhus C, Denmark.,Danish Research Institute of Translational Neuroscience - DANDRITE, Nordic-EMBL Partnership for Molecular Medicine, Aarhus C, Denmark
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21
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Roland BP, Naito T, Best JT, Arnaiz-Yépez C, Takatsu H, Yu RJ, Shin HW, Graham TR. Yeast and human P4-ATPases transport glycosphingolipids using conserved structural motifs. J Biol Chem 2018; 294:1794-1806. [PMID: 30530492 DOI: 10.1074/jbc.ra118.005876] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2018] [Revised: 11/29/2018] [Indexed: 12/21/2022] Open
Abstract
Lipid transport is an essential process with manifest importance to human health and disease. Phospholipid flippases (P4-ATPases) transport lipids across the membrane bilayer and are involved in signal transduction, cell division, and vesicular transport. Mutations in flippase genes cause or contribute to a host of diseases, such as cholestasis, neurological deficits, immunological dysfunction, and metabolic disorders. Genome-wide association studies have shown that ATP10A and ATP10D variants are associated with an increased risk of diabetes, obesity, myocardial infarction, and atherosclerosis. Moreover, ATP10D SNPs are associated with elevated levels of glucosylceramide (GlcCer) in plasma from diverse European populations. Although sphingolipids strongly contribute to metabolic disease, little is known about how GlcCer is transported across cell membranes. Here, we identify a conserved clade of P4-ATPases from Saccharomyces cerevisiae (Dnf1, Dnf2), Schizosaccharomyces pombe (Dnf2), and Homo sapiens (ATP10A, ATP10D) that transport GlcCer bearing an sn2 acyl-linked fluorescent tag. Further, we establish structural determinants necessary for recognition of this sphingolipid substrate. Using enzyme chimeras and site-directed mutagenesis, we observed that residues in transmembrane (TM) segments 1, 4, and 6 contribute to GlcCer selection, with a conserved glutamine in the center of TM4 playing an essential role. Our molecular observations help refine models for substrate translocation by P4-ATPases, clarify the relationship between these flippases and human disease, and have fundamental implications for membrane organization and sphingolipid homeostasis.
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Affiliation(s)
- Bartholomew P Roland
- From the Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37235 and
| | - Tomoki Naito
- the Graduate School of Pharmaceutical Science, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Jordan T Best
- From the Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37235 and
| | - Cayetana Arnaiz-Yépez
- From the Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37235 and
| | - Hiroyuki Takatsu
- the Graduate School of Pharmaceutical Science, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Roger J Yu
- From the Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37235 and
| | - Hye-Won Shin
- the Graduate School of Pharmaceutical Science, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Todd R Graham
- From the Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37235 and
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22
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Mangano S, Martínez Pacheco J, Marino-Buslje C, Estevez JM. How Does pH Fit in with Oscillating Polar Growth? TRENDS IN PLANT SCIENCE 2018; 23:479-489. [PMID: 29605100 DOI: 10.1016/j.tplants.2018.02.008] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 02/08/2018] [Accepted: 02/23/2018] [Indexed: 05/22/2023]
Abstract
Polar growth in root hairs and pollen tubes is an excellent model for investigating plant cell size regulation. While linear plant growth is historically explained by the acid growth theory, which considers that auxin triggers apoplastic acidification by activating plasma membrane P-type H+-ATPases (AHAs) along with cell wall relaxation over long periods, the apoplastic pH (apopH) regulatory mechanisms are unknown for polar growth. Polar growth is a fast process mediated by rapid oscillations that repeat every ∼20-40s. In this review, we explore a reactive oxygen species (ROS)-dependent mechanism that could generate oscillating apopH gradients in a coordinated manner with growth and Ca2+ oscillations. We propose possible mechanisms by which apopH oscillations are coordinated with polar growth together with ROS and Ca2+ waves.
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Affiliation(s)
- Silvina Mangano
- Fundación Instituto Leloir and Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA-CONICET), Av. Patricias Argentinas 435, Buenos Aires CP C1405BWE, Argentina; These authors contributed equally to this work
| | - Javier Martínez Pacheco
- Fundación Instituto Leloir and Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA-CONICET), Av. Patricias Argentinas 435, Buenos Aires CP C1405BWE, Argentina; Department of Genetics and Phytopathology, Biological Research Division, Tobacco Research Institute, Carretera Tumbadero, 8 1/2 km, San Antonio de los Baños, Artemisa, Cuba; These authors contributed equally to this work
| | - Cristina Marino-Buslje
- Fundación Instituto Leloir and Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA-CONICET), Av. Patricias Argentinas 435, Buenos Aires CP C1405BWE, Argentina
| | - José M Estevez
- Fundación Instituto Leloir and Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA-CONICET), Av. Patricias Argentinas 435, Buenos Aires CP C1405BWE, Argentina.
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23
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Croll TI. ISOLDE: a physically realistic environment for model building into low-resolution electron-density maps. Acta Crystallogr D Struct Biol 2018; 74:519-530. [PMID: 29872003 PMCID: PMC6096486 DOI: 10.1107/s2059798318002425] [Citation(s) in RCA: 917] [Impact Index Per Article: 152.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2017] [Accepted: 02/09/2018] [Indexed: 01/19/2023] Open
Abstract
This paper introduces ISOLDE, a new software package designed to provide an intuitive environment for high-fidelity interactive remodelling/refinement of macromolecular models into electron-density maps. ISOLDE combines interactive molecular-dynamics flexible fitting with modern molecular-graphics visualization and established structural biology libraries to provide an immersive interface wherein the model constantly acts to maintain physically realistic conformations as the user interacts with it by directly tugging atoms with a mouse or haptic interface or applying/removing restraints. In addition, common validation tasks are accelerated and visualized in real time. Using the recently described 3.8 Å resolution cryo-EM structure of the eukaryotic minichromosome maintenance (MCM) helicase complex as a case study, it is demonstrated how ISOLDE can be used alongside other modern refinement tools to avoid common pitfalls of low-resolution modelling and improve the quality of the final model. A detailed analysis of changes between the initial and final model provides a somewhat sobering insight into the dangers of relying on a small number of validation metrics to judge the quality of a low-resolution model.
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Affiliation(s)
- Tristan Ian Croll
- Cambridge Institute for Medical Research, University of Cambridge, Wellcome Trust/MRC Building, Cambridge CB2 0XY, England
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24
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Crystal structures of the gastric proton pump. Nature 2018; 556:214-218. [PMID: 29618813 DOI: 10.1038/s41586-018-0003-8] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Accepted: 02/21/2018] [Indexed: 12/13/2022]
Abstract
The gastric proton pump-the H+, K+-ATPase-is a P-type ATPase responsible for acidifying the gastric juice down to pH 1. This corresponds to a million-fold proton gradient across the membrane of the parietal cell, the steepest known cation gradient of any mammalian tissue. The H+, K+-ATPase is an important target for drugs that treat gastric acid-related diseases. Here we present crystal structures of the H+, K+-ATPase in complex with two blockers, vonoprazan and SCH28080, in the luminal-open state, at 2.8 Å resolution. The drugs have partially overlapping but clearly distinct binding modes in the middle of a conduit running from the gastric lumen to the cation-binding site. The crystal structures suggest that the tight configuration at the cation-binding site lowers the pK a value of Glu820 sufficiently to enable the release of a proton even into the pH 1 environment of the stomach.
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25
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Sablok G, Hayward RJ, Davey PA, Santos RP, Schliep M, Larkum A, Pernice M, Dolferus R, Ralph PJ. SeagrassDB: An open-source transcriptomics landscape for phylogenetically profiled seagrasses and aquatic plants. Sci Rep 2018; 8:2749. [PMID: 29426939 PMCID: PMC5807536 DOI: 10.1038/s41598-017-18782-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Accepted: 12/11/2017] [Indexed: 12/04/2022] Open
Abstract
Seagrasses and aquatic plants are important clades of higher plants, significant for carbon sequestration and marine ecological restoration. They are valuable in the sense that they allow us to understand how plants have developed traits to adapt to high salinity and photosynthetically challenged environments. Here, we present a large-scale phylogenetically profiled transcriptomics repository covering seagrasses and aquatic plants. SeagrassDB encompasses a total of 1,052,262 unigenes with a minimum and maximum contig length of 8,831 bp and 16,705 bp respectively. SeagrassDB provides access to 34,455 transcription factors, 470,568 PFAM domains, 382,528 prosite models and 482,121 InterPro domains across 9 species. SeagrassDB allows for the comparative gene mining using BLAST-based approaches and subsequent unigenes sequence retrieval with associated features such as expression (FPKM values), gene ontologies, functional assignments, family level classification, Interpro domains, KEGG orthology (KO), transcription factors and prosite information. SeagrassDB is available to the scientific community for exploring the functional genic landscape of seagrass and aquatic plants at: http://115.146.91.129/index.php.
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Affiliation(s)
- Gaurav Sablok
- Climate Change Cluster (C3), University of Technology Sydney, PO Box 123 Broadway, NSW 2007, Australia.
| | - Regan J Hayward
- Climate Change Cluster (C3), University of Technology Sydney, PO Box 123 Broadway, NSW 2007, Australia
| | - Peter A Davey
- Climate Change Cluster (C3), University of Technology Sydney, PO Box 123 Broadway, NSW 2007, Australia
| | - Rosiane P Santos
- Laboratório de Recursos Genéticos, Universidade Federal de São João Del-Rei, Campus CTAN, São João Del Rei, Minas Gerais, 36307-352, Brazil
| | - Martin Schliep
- Climate Change Cluster (C3), University of Technology Sydney, PO Box 123 Broadway, NSW 2007, Australia
| | - Anthony Larkum
- Climate Change Cluster (C3), University of Technology Sydney, PO Box 123 Broadway, NSW 2007, Australia
| | - Mathieu Pernice
- Climate Change Cluster (C3), University of Technology Sydney, PO Box 123 Broadway, NSW 2007, Australia
| | - Rudy Dolferus
- CSIRO Agriculture and Food, GPO Box 1700, Canberra, ACT 2601, Australia
| | - Peter J Ralph
- Climate Change Cluster (C3), University of Technology Sydney, PO Box 123 Broadway, NSW 2007, Australia.
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