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Aquaporins Display a Diversity in their Substrates. J Membr Biol 2023; 256:1-23. [PMID: 35986775 DOI: 10.1007/s00232-022-00257-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Accepted: 07/13/2022] [Indexed: 02/07/2023]
Abstract
Aquaporins constitute a family of transmembrane proteins that function to transport water and other small solutes across the cell membrane. Aquaporins family members are found in diverse life forms. Aquaporins share the common structural fold consisting of six transmembrane alpha helices with a central water-transporting channel. Four such monomers assemble together to form tetramers as their biological unit. Initially, aquaporins were discovered as water-transporting channels, but several studies supported their involvement in mediating the facilitated diffusion of different solutes. The so-called water channel is able to transport a variety of substrates ranging from a neutral molecule to a charged molecule or a small molecule to a bulky molecule or even a gas molecule. This article gives an overview of a diverse range of substrates conducted by aquaporin family members. Prime focus is on human aquaporins where aquaporins show a wide tissue distribution and substrate specificity leading to various physiological functions. This review also highlights the structural mechanisms leading to the transport of water and glycerol. More research is needed to understand how one common fold enables the aquaporins to transport an array of solutes.
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Local Attraction of Substrates and Co-Substrates Enhances Weak Acid and Base Transmembrane Transport. Biomolecules 2022; 12:biom12121794. [PMID: 36551222 PMCID: PMC9775063 DOI: 10.3390/biom12121794] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 11/25/2022] [Accepted: 11/28/2022] [Indexed: 12/03/2022] Open
Abstract
The transmembrane transport of weak acid and base metabolites depends on the local pH conditions that affect the protonation status of the substrates and the availability of co-substrates, typically protons. Different protein designs ensure the attraction of substrates and co-substrates to the transporter entry sites. These include electrostatic surface charges on the transport proteins and complexation with seemingly transport-unrelated proteins that provide substrate and/or proton antenna, or enzymatically generate substrates in place. Such protein assemblies affect transport rates and directionality. The lipid membrane surface also collects and transfers protons. The complexity in the various systems enables adjustability and regulation in a given physiological or pathophysiological situation. This review describes experimentally shown principles in the attraction and facilitation of weak acid and base transport substrates, including monocarboxylates, ammonium, bicarbonate, and arsenite, plus protons as a co-substrate.
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Somee R, Eslami G, Vakili M. Mitogen-Activated Protein Kinase and Aquaglyceroporin Gene Expression in Treatment Failure Leishmania major. Acta Parasitol 2022; 67:309-315. [PMID: 34415479 DOI: 10.1007/s11686-021-00463-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 08/13/2021] [Indexed: 02/08/2023]
Abstract
PURPOSE Leishmaniasis comprises various clinical forms mainly including cutaneous, muco-cutaneous, and visceral leishmaniasis; caused by Leishmania species. Antimoniate is the first-line treatment but some cases showed no response to treatment in the worldwide. In this study, mitogen-activated protein kinase (MAPK) and aquaglyceroporin 1 (AQP1) gene expressions were assessed in treatment failure clinical isolates of Leishmania major. Also, molecular and phylogenic analyses of the mentioned isolates were performed. METHODS Samples were obtained from the patients with suspicious CL referred to the laboratory of Diagnosis Center, Gorgan Province, Iran, from October 2016 to December 2019. Detection and identification of the parasite was performed. The genes expressions of MAPK1 and AQP1 were done using SYBR Green real-time PCR. The AQP1 gene from the isolates with treatment failure was sequenced and analyzed using BLAST and multiple alignments. The phylogenic analysis was done using MEGA7. The statistical analysis was done using SPSS 16.0 by non-parametric Mann-Whitney U test. RESULTS All clinical isolates were detected L. major. The mean AQP1 and MAPK1 gene expressions in treatment failure isolates were 58.71 and 6.139 fold less than the ones in treatment response isolates, respectively. Based on the AQP1 gene sequence, a nucleotide change of aspartic acid with asparagine at the site 234 was observed. Phylogenic tree analysis showed three groups with the minimum dissimilarity of 0.008 between TF isolates with the standard L. major strains. CONCLUSION We showed that MAPK1 and AQP1 may have critical roles in response to antimoniate in clinical isolates L. major in this study.
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Melton AE, Beck J, Galla SJ, Jenkins J, Handley L, Kim M, Grimwood J, Schmutz J, Richardson BA, Serpe M, Novak S, Buerki S. A draft genome provides hypotheses on drought tolerance in a keystone plant species in Western North America threatened by climate change. Ecol Evol 2021; 11:15417-15429. [PMID: 34765187 PMCID: PMC8571618 DOI: 10.1002/ece3.8245] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 08/12/2021] [Accepted: 10/01/2021] [Indexed: 11/17/2022] Open
Abstract
Climate change presents distinct ecological and physiological challenges to plants as extreme climate events become more common. Understanding how species have adapted to drought, especially ecologically important nonmodel organisms, will be crucial to elucidate potential biological pathways for drought adaptation and inform conservation strategies. To aid in genome-to-phenome research, a draft genome was assembled for a diploid individual of Artemisia tridentata subsp. tridentata, a threatened keystone shrub in western North America. While this taxon has few genetic resources available and genetic/genomics work has proven difficult due to genetic heterozygosity in the past, a draft genome was successfully assembled. Aquaporin (AQP) genes and their promoter sequences were mined from the draft genome to predict mechanisms regulating gene expression and generate hypotheses on key genes underpinning drought response. Fifty-one AQP genes were fully assembled within the draft genome. Promoter and phylogenetic analyses revealed putative duplicates of A. tridentata subsp. tridentata AQPs which have experienced differentiation in promoter elements, potentially supporting novel biological pathways. Comparison with nondrought-tolerant congener supports enrichments of AQP genes in this taxon during adaptation to drought stress. Differentiation of promoter elements revealed that paralogues of some genes have evolved to function in different pathways, highlighting these genes as potential candidates for future research and providing critical hypotheses for future genome-to-phenome work.
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Affiliation(s)
- Anthony E. Melton
- Department of Biological SciencesBoise State UniversityBoiseIdahoUSA
| | - James Beck
- Department of ComputingBoise State UniversityBoiseIdahoUSA
| | | | - Jerry Jenkins
- HudsonAlpha Institute for BiotechnologyHuntsvilleAlabamaUSA
| | - Lori Handley
- HudsonAlpha Institute for BiotechnologyHuntsvilleAlabamaUSA
| | - Min Kim
- HudsonAlpha Institute for BiotechnologyHuntsvilleAlabamaUSA
| | - Jane Grimwood
- HudsonAlpha Institute for BiotechnologyHuntsvilleAlabamaUSA
| | - Jeremy Schmutz
- HudsonAlpha Institute for BiotechnologyHuntsvilleAlabamaUSA
| | | | - Marcelo Serpe
- Department of Biological SciencesBoise State UniversityBoiseIdahoUSA
| | - Stephen Novak
- Department of Biological SciencesBoise State UniversityBoiseIdahoUSA
| | - Sven Buerki
- Department of Biological SciencesBoise State UniversityBoiseIdahoUSA
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Pimpão C, Wragg D, Bonsignore R, Aikman B, Pedersen PA, Leoni S, Soveral G, Casini A. Mechanisms of irreversible aquaporin-10 inhibition by organogold compounds studied by combined biophysical methods and atomistic simulations. Metallomics 2021; 13:6360981. [PMID: 34468767 DOI: 10.1093/mtomcs/mfab053] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 08/18/2021] [Indexed: 11/14/2022]
Abstract
The inhibition of glycerol permeation via human aquaporin-10 (hAQP10) by organometallic gold complexes has been studied by stopped-flow fluorescence spectroscopy, and its mechanism has been described using molecular modelling and atomistic simulations. The most effective hAQP10 inhibitors are cyclometalated Au(III) C^N compounds known to efficiently react with cysteine residues leading to the formation of irreversible C-S bonds. Functional assays also demonstrate the irreversibility of the binding to hAQP10 by the organometallic complexes. The obtained computational results by metadynamics show that the local arylation of Cys209 in hAQP10 by one of the gold inhibitors is mapped into a global change of the overall free energy of glycerol translocation across the channel. Our study further pinpoints the need to understand the mechanism of glycerol and small molecule permeation as a combination of local structural motifs and global pore conformational changes, which are taking place on the scale of the translocation process and whose study, therefore, require sophisticated molecular dynamics strategies.
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Affiliation(s)
- Catarina Pimpão
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, 1649-003 Lisboa, Portugal
| | - Darren Wragg
- Department of Chemistry, Technical University of Munich, 85747 Garching bei München, Germany
| | - Riccardo Bonsignore
- Department of Chemistry, Technical University of Munich, 85747 Garching bei München, Germany
| | - Brech Aikman
- Department of Chemistry, Technical University of Munich, 85747 Garching bei München, Germany
- School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, UK
| | - Per Amstrup Pedersen
- Department of Biology, University of Copenhagen, Universitetsparken 13, DK-2100 Copenhagen OE, Denmark
| | - Stefano Leoni
- School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, UK
| | - Graça Soveral
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, 1649-003 Lisboa, Portugal
| | - Angela Casini
- Department of Chemistry, Technical University of Munich, 85747 Garching bei München, Germany
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AQPX-cluster aquaporins and aquaglyceroporins are asymmetrically distributed in trypanosomes. Commun Biol 2021; 4:953. [PMID: 34376792 PMCID: PMC8355241 DOI: 10.1038/s42003-021-02472-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 07/21/2021] [Indexed: 02/07/2023] Open
Abstract
Major Intrinsic Proteins (MIPs) are membrane channels that permeate water and other small solutes. Some trypanosomatid MIPs mediate the uptake of antiparasitic compounds, placing them as potential drug targets. However, a thorough study of the diversity of these channels is still missing. Here we place trypanosomatid channels in the sequence-function space of the large MIP superfamily through a sequence similarity network. This analysis exposes that trypanosomatid aquaporins integrate a distant cluster from the currently defined MIP families, here named aquaporin X (AQPX). Our phylogenetic analyses reveal that trypanosomatid MIPs distribute exclusively between aquaglyceroporin (GLP) and AQPX, being the AQPX family expanded in the Metakinetoplastina common ancestor before the origin of the parasitic order Trypanosomatida. Synteny analysis shows how African trypanosomes specifically lost AQPXs, whereas American trypanosomes specifically lost GLPs. AQPXs diverge from already described MIPs on crucial residues. Together, our results expose the diversity of trypanosomatid MIPs and will aid further functional, structural, and physiological research needed to face the potentiality of the AQPXs as gateways for trypanocidal drugs.
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Tunes LG, Ascher DB, Pires DEV, Monte-Neto RL. The mutation G133D on Leishmania guyanensis AQP1 is highly destabilizing as revealed by molecular modeling and hypo-osmotic shock assay. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2021; 1863:183682. [PMID: 34175297 DOI: 10.1016/j.bbamem.2021.183682] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Revised: 06/11/2021] [Accepted: 06/14/2021] [Indexed: 10/21/2022]
Abstract
The Leishmania aquaglyceroporin 1 (AQP1) plays an important role in osmoregulation and antimony (Sb) uptake, being determinant for resistance to antimony. We have previously demonstrated that G133D mutation on L. guyanensis AQP1 (LgAQP1) leads to reduced Sb uptake. Here, we investigated the effects of G133D mutation on LgAQP1 structure, associated with Sb uptake and alterations in osmoregulation capacity. High confidence molecular models of wild-type LgAQP1 as well as the LgAQP1::G133D mutant were constructed and optimized via comparative homology modeling. Computational methods from the mCSM platform were used to evaluate the effects on protein stability and on its ability to bind to glycerol. Functional validation of the disruptive effect of the mutation on LgAQP1 was done by challenging the parasites with hypo-osmotic chock. Glycine 133 is on transmembrane helix 3, buried in the membrane in both open and closed conformation. G133D mutation was predicted to be highly destabilizing, as it alters the helical bundling arrangement in order to accommodate the aspartic acid side chain. The shift in helices also resulted in fewer favorable contacts with glycerol in the channel, which would explain the reduced affinity for similar small molecules as SbO3. Under hypo-osmotic condition, L. guyanensis AQP1G133D presented a 3-fold increase in cellular volume and pronounced delay to recover osmosis homeostasis when compared to the wild-type, a profile that was enhanced in LgAQP1-/- mutants. In conclusion, G133D is a highly disruptive mutation that will destabilize the monomer, compromise tetramer formation and alter pore conformation, leading to reduced Sb uptake and deficient osmoregulation.
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Affiliation(s)
- Luiza G Tunes
- Biotechnology Applied to Pathogens Instituto René Rachou, Fundação Oswaldo Cruz (Fiocruz Minas), Av. Augusto de Lima, 1715, Belo Horizonte 30190-009, MG, Brazil; The University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, 75390-8511 Dallas, TX, USA.
| | - David B Ascher
- Structural Biology and Bioinformatics, Department of Biochemistry and Molecular Biology, The University of Melbourne, Bio21 Institute, 30 Flemington Rd, Parkville, VIC 3052, Melbourne, Australia; Computational Biology and Clinical Informatics, Baker Heart and Diabetes Institute, VIC 3004, Melbourne, Australia.
| | - Douglas E V Pires
- Structural Biology and Bioinformatics, Department of Biochemistry and Molecular Biology, The University of Melbourne, Bio21 Institute, 30 Flemington Rd, Parkville, VIC 3052, Melbourne, Australia; Computational Biology and Clinical Informatics, Baker Heart and Diabetes Institute, VIC 3004, Melbourne, Australia; School of Computing and Information Systems, The University of Melbourne, Doug McDonell Building, VIC 3010, Parkville, Melbourne, Australia.
| | - Rubens L Monte-Neto
- Biotechnology Applied to Pathogens Instituto René Rachou, Fundação Oswaldo Cruz (Fiocruz Minas), Av. Augusto de Lima, 1715, Belo Horizonte 30190-009, MG, Brazil.
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Tyerman SD, McGaughey SA, Qiu J, Yool AJ, Byrt CS. Adaptable and Multifunctional Ion-Conducting Aquaporins. ANNUAL REVIEW OF PLANT BIOLOGY 2021; 72:703-736. [PMID: 33577345 DOI: 10.1146/annurev-arplant-081720-013608] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Aquaporins function as water and neutral solute channels, signaling hubs, disease virulence factors, and metabolon components. We consider plant aquaporins that transport ions compared to some animal counterparts. These are candidates for important, as yet unidentified, cation and anion channels in plasma, tonoplast, and symbiotic membranes. For those individual isoforms that transport ions, water, and gases, the permeability spans 12 orders of magnitude. This requires tight regulation of selectivity via protein interactions and posttranslational modifications. A phosphorylation-dependent switch between ion and water permeation in AtPIP2;1 might be explained by coupling between the gates of the four monomer water channels and the central pore of the tetramer. We consider the potential for coupling between ion and water fluxes that could form the basis of an electroosmotic transducer. A grand challenge in understanding the roles of ion transporting aquaporins is their multifunctional modes that are dependent on location, stress, time, and development.
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Affiliation(s)
- Stephen D Tyerman
- Australian Research Council (ARC) Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, University of Adelaide, Glen Osmond, South Australia 5064, Australia; ,
| | - Samantha A McGaughey
- ARC Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology, Australian National University, Acton, Australian Capital Territory 0200, Australia; ,
| | - Jiaen Qiu
- Australian Research Council (ARC) Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, University of Adelaide, Glen Osmond, South Australia 5064, Australia; ,
| | - Andrea J Yool
- Adelaide Medical School, University of Adelaide, Adelaide, South Australia 5005, Australia;
| | - Caitlin S Byrt
- ARC Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology, Australian National University, Acton, Australian Capital Territory 0200, Australia; ,
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The Ionophores CCCP and Gramicidin but Not Nigericin Inhibit Trypanosoma brucei Aquaglyceroporins at Neutral pH. Cells 2020; 9:cells9102335. [PMID: 33096791 PMCID: PMC7589649 DOI: 10.3390/cells9102335] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 10/16/2020] [Accepted: 10/20/2020] [Indexed: 12/16/2022] Open
Abstract
Human African trypanosomiasis (HAT) is caused by Trypanosoma brucei parasites. The T. brucei aquaglyceroporin isoform 2, TbAQP2, has been linked to the uptake of pentamidine. Negative membrane potentials and transmembrane pH gradients were suggested to promote transport of the dicationic antitrypanosomal drug. Application of ionophores to trypanosomes further hinted at direct inhibition of TbAQP2 by carbonyl cyanide m-chlorophenyl hydrazone (CCCP). Here, we tested for direct effects of three classical ionophores (CCCP, nigericin, gramicidin) on the functionality of TbAQP2 and the related TbAQP3 at conditions that are independent from the membrane potential or a proton gradient. We expressed TbAQP2 and TbAQP3 in yeast, and determined permeability of uncharged glycerol at neutral pH using stopped-flow light scattering. The mobile proton carrier CCCP directly inhibited TbAQP2 glycerol permeability at an IC50 of 2 µM, and TbAQP3 to a much lesser extent (IC50 around 1 mM) likely due to different selectivity filter layouts. Nigericin, another mobile carrier, left both isoforms unaffected. The membrane-integral pore-forming gramicidin evenly inhibited TbAQP2 and TbAQP2 in the double-digit micromolar range. Our data exemplify the need for suitable controls to detect unwanted ionophore side effects even when used at concentrations that are typically recommended to disturb the transmembrane ion distribution.
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Alghamdi AH, Munday JC, Campagnaro GD, Gurvic D, Svensson F, Okpara CE, Kumar A, Quintana J, Martin Abril ME, Milić P, Watson L, Paape D, Settimo L, Dimitriou A, Wielinska J, Smart G, Anderson LF, Woodley CM, Kelly SPY, Ibrahim HM, Hulpia F, Al-Salabi MI, Eze AA, Sprenger T, Teka IA, Gudin S, Weyand S, Field M, Dardonville C, Tidwell RR, Carrington M, O'Neill P, Boykin DW, Zachariae U, De Koning HP. Positively selected modifications in the pore of TbAQP2 allow pentamidine to enter Trypanosoma brucei. eLife 2020; 9:56416. [PMID: 32762841 PMCID: PMC7473772 DOI: 10.7554/elife.56416] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 08/06/2020] [Indexed: 11/25/2022] Open
Abstract
Mutations in the Trypanosoma brucei aquaporin AQP2 are associated with resistance to pentamidine and melarsoprol. We show that TbAQP2 but not TbAQP3 was positively selected for increased pore size from a common ancestor aquaporin. We demonstrate that TbAQP2’s unique architecture permits pentamidine permeation through its central pore and show how specific mutations in highly conserved motifs affect drug permeation. Introduction of key TbAQP2 amino acids into TbAQP3 renders the latter permeable to pentamidine. Molecular dynamics demonstrates that permeation by dicationic pentamidine is energetically favourable in TbAQP2, driven by the membrane potential, although aquaporins are normally strictly impermeable for ionic species. We also identify the structural determinants that make pentamidine a permeant although most other diamidine drugs are excluded. Our results have wide-ranging implications for optimising antitrypanosomal drugs and averting cross-resistance. Moreover, these new insights in aquaporin permeation may allow the pharmacological exploitation of other members of this ubiquitous gene family. African sleeping sickness is a potentially deadly illness caused by the parasite Trypanosoma brucei. The disease is treatable, but many of the current treatments are old and are becoming increasingly ineffective. For instance, resistance is growing against pentamidine, a drug used in the early stages in the disease, as well as against melarsoprol, which is deployed when the infection has progressed to the brain. Usually, cases resistant to pentamidine are also resistant to melarsoprol, but it is still unclear why, as the drugs are chemically unrelated. Studies have shown that changes in a water channel called aquaglyceroporin 2 (TbAQP2) contribute to drug resistance in African sleeping sickness; this suggests that it plays a role in allowing drugs to kill the parasite. This molecular ‘drain pipe’ extends through the surface of T. brucei, and should allow only water and a molecule called glycerol in and out of the cell. In particular, the channel should be too narrow to allow pentamidine or melarsoprol to pass through. One possibility is that, in T. brucei, the TbAQP2 channel is abnormally wide compared to other members of its family. Alternatively, pentamidine and melarsoprol may only bind to TbAQP2, and then ‘hitch a ride’ when the protein is taken into the parasite as part of the natural cycle of surface protein replacement. Alghamdi et al. aimed to tease out these hypotheses. Computer models of the structure of the protein were paired with engineered changes in the key areas of the channel to show that, in T. brucei, TbAQP2 provides a much broader gateway into the cell than observed for similar proteins. In addition, genetic analysis showed that this version of TbAQP2 has been actively selected for during the evolution process of T. brucei. This suggests that the parasite somehow benefits from this wider aquaglyceroporin variant. This is a new resistance mechanism, and it is possible that aquaglyceroporins are also larger than expected in other infectious microbes. The work by Alghamdi et al. therefore provides insight into how other germs may become resistant to drugs.
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Affiliation(s)
- Ali H Alghamdi
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Jane C Munday
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | | | - Dominik Gurvic
- Computational Biology Centre for Translational and Interdisciplinary Research, University of Dundee, Dundee, United Kingdom
| | - Fredrik Svensson
- IOTA Pharmaceuticals Ltd, St Johns Innovation Centre, Cambridge, United Kingdom
| | - Chinyere E Okpara
- Department of Chemistry, University of Liverpool, Liverpool, United Kingdom
| | - Arvind Kumar
- Chemistry Department, Georgia State University, Atlanta, United States
| | - Juan Quintana
- School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | | | - Patrik Milić
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Laura Watson
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Daniel Paape
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Luca Settimo
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Anna Dimitriou
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Joanna Wielinska
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Graeme Smart
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Laura F Anderson
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | | | - Siu Pui Ying Kelly
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Hasan Ms Ibrahim
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Fabian Hulpia
- Laboratory for Medicinal Chemistry, University of Ghent, Ghent, Belgium
| | - Mohammed I Al-Salabi
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Anthonius A Eze
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Teresa Sprenger
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Ibrahim A Teka
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Simon Gudin
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Simone Weyand
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Mark Field
- School of Life Sciences, University of Dundee, Dundee, United Kingdom.,Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Ceske Budejovice, Czech Republic
| | | | - Richard R Tidwell
- Department of Pathology and Lab Medicine, University of North Carolina at Chapel Hill, Chapel Hill, United States
| | - Mark Carrington
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Paul O'Neill
- Department of Chemistry, University of Liverpool, Liverpool, United Kingdom
| | - David W Boykin
- Chemistry Department, Georgia State University, Atlanta, United States
| | - Ulrich Zachariae
- Computational Biology Centre for Translational and Interdisciplinary Research, University of Dundee, Dundee, United Kingdom
| | - Harry P De Koning
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
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Zhang L, Chen L, Dong H. Plant Aquaporins in Infection by and Immunity Against Pathogens - A Critical Review. FRONTIERS IN PLANT SCIENCE 2019; 10:632. [PMID: 31191567 PMCID: PMC6546722 DOI: 10.3389/fpls.2019.00632] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 04/26/2019] [Indexed: 05/18/2023]
Abstract
Plant aquaporins (AQPs) of the plasma membrane intrinsic protein (PIP) family face constant risk of hijack by pathogens aiming to infect plants. PIPs can also be involved in plant immunity against infection. This review will utilize two case studies to discuss biochemical and structural mechanisms that govern the functions of PIPs in the regulation of plant infection and immunity. The first example concerns the interaction between rice Oryza sativa and the bacterial blight pathogen Xanthomonas oryzae pv. oryzae (Xoo). To infect rice, Xoo uses the type III (T3) secretion system to secrete the proteic translocator Hpa1, and Hpa1 subsequently mediates the translocation of T3 effectors secreted by this system. Once shifted from bacteria into rice cells, effectors exert virulent or avirulent effects depending on the susceptibility of the rice varieties. The translocator function of Hpa1 requires cooperation with OsPIP1;3, the rice interactor of Hpa1. This role of OsPIP1;3 is related to regulatory models of effector translocation. The regulatory models have been proposed as, translocon-dependent delivery, translocon-independent pore formation, and effector endocytosis with membrane protein/lipid trafficking. The second case study includes the interaction of Hpa1 with the H2O2 transport channel AtPIP1;4, and the associated consequence for H2O2 signal transduction of immunity pathways in Arabidopsis thaliana, a non-host of Xoo. H2O2 is generated in the apoplast upon induction by a pathogen or microbial pattern. H2O2 from this source translocates quickly into Arabidopsis cells, where it interacts with pathways of intracellular immunity to confer plant resistance against diseases. To expedite H2O2 transport, AtPIP1;4 must adopt a specific conformation in a number of ways, including channel width extension through amino acid interactions and selectivity for H2O2 through amino acid protonation and tautomeric reactions. Both topics will reference relevant studies, conducted on other organisms and AQPs, to highlight possible mechanisms of T3 effector translocation currently under debate, and highlight the structural basis of AtPIP1;4 in H2O2 transport facilitated by gating and trafficking regulation.
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Affiliation(s)
- Liyuan Zhang
- Plant Immunity Research Group, National Key Laboratory of Crop Science, Department of Plant Pathology, Shandong Agricultural University, Tai’an, China
| | - Lei Chen
- Plant Immunity Research Group, National Key Laboratory of Crop Science, Department of Plant Pathology, Shandong Agricultural University, Tai’an, China
| | - Hansong Dong
- Plant Immunity Research Group, National Key Laboratory of Crop Science, Department of Plant Pathology, Shandong Agricultural University, Tai’an, China
- Plant Immunity Laboratory, Department of Plant Pathology, Nanjing Agricultural University, Nanjing, China
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An aquaporin mediates cell shape change required for cellular immunity in the beet armyworm, Spodoptera exigua. Sci Rep 2019; 9:4988. [PMID: 30899076 PMCID: PMC6428837 DOI: 10.1038/s41598-019-41541-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Accepted: 03/08/2019] [Indexed: 11/08/2022] Open
Abstract
Cellular immunity in insects is accompanied by change in hemocyte shape. This study hypothesizes that cytoskeletal rearrangement is accompanied by transmembrane water transport to change cell volume, thus changing cell shape. A water-transporting pore (=aquaporin:AQP) has been identified in the beet armyworm, Spodoptera exigua. Its expression was detected in all developmental stages and tissues, although its transcription levels were different between biotic and abiotic conditions. Heterologous expression of Se-AQP in Sf9 cells showed that Se-AQP was localized on cell membrane. RNA interference (RNAi) using double-stranded RNA effectively suppressed its transcript levels. Under different ionic concentrations, hemocytes of RNAi-treated larvae did not change cell volume presumably due to malfunction in water transportation. Se-AQP might participate in glycerol transport because up-regulation of hemolymph glycerol titer after rapid cold-hardening was prevented by RNAi treatment against Se-AQP expression. The inhibitory effect of RNAi treatment on change of cell shape significantly impaired cellular immune responses such as phagocytosis and nodule formation upon bacterial challenge. RNAi treatment also significantly interfered with immature development of S. exigua. These results indicate that Se-AQP plays a crucial role in cell shape change that is required for cellular immunity and other physiological processes.
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13
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Aikman B, de Almeida A, Meier-Menches SM, Casini A. Aquaporins in cancer development: opportunities for bioinorganic chemistry to contribute novel chemical probes and therapeutic agents. Metallomics 2019; 10:696-712. [PMID: 29766198 DOI: 10.1039/c8mt00072g] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Aquaporins (AQPs) are membrane proteins allowing permeation of water, glycerol & hydrogen peroxide across biomembranes, and playing an important role in water homeostasis in different organs, exocrine gland secretion, urine concentration, skin moisturization, fat metabolism and neural signal transduction. Notably, a large number of studies showed that AQPs are closely associated with cancer biological functions and expressed in more than 20 human cancer cell types. Furthermore, AQP expression is positively correlated with tumour types, grades, proliferation, migration, angiogenesis, as well as tumour-associated oedema, rendering these membrane channels attractive as both diagnostic and therapeutic targets in cancer. Recent developments in the field of AQPs modulation have identified coordination metal-based complexes as potent and selective inhibitors of aquaglyceroporins, opening new avenues in the application of inorganic compounds in medicine and chemical biology. The present review is aimed at providing an overview on AQP structure and function, mainly in relation to cancer. In this context, the exploration of coordination metal compounds as possible inhibitors of aquaporins may open the way to novel chemical approaches to study AQP roles in tumour growth and potentially to new drug families. Thus, we describe recent results in the field and reflect upon the potential of inorganic chemistry in providing compounds to modulate the activity of "elusive" membrane targets as the aquaporins.
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Affiliation(s)
- Brech Aikman
- School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, UK.
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14
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Ozu M, Galizia L, Acuña C, Amodeo G. Aquaporins: More Than Functional Monomers in a Tetrameric Arrangement. Cells 2018; 7:E209. [PMID: 30423856 PMCID: PMC6262540 DOI: 10.3390/cells7110209] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2018] [Revised: 10/27/2018] [Accepted: 11/07/2018] [Indexed: 12/11/2022] Open
Abstract
Aquaporins (AQPs) function as tetrameric structures in which each monomer has its own permeable pathway. The combination of structural biology, molecular dynamics simulations, and experimental approaches has contributed to improve our knowledge of how protein conformational changes can challenge its transport capacity, rapidly altering the membrane permeability. This review is focused on evidence that highlights the functional relationship between the monomers and the tetramer. In this sense, we address AQP permeation capacity as well as regulatory mechanisms that affect the monomer, the tetramer, or tetramers combined in complex structures. We therefore explore: (i) water permeation and recent evidence on ion permeation, including the permeation pathway controversy-each monomer versus the central pore of the tetramer-and (ii) regulatory mechanisms that cannot be attributed to independent monomers. In particular, we discuss channel gating and AQPs that sense membrane tension. For the latter we propose a possible mechanism that includes the monomer (slight changes of pore shape, the number of possible H-bonds between water molecules and pore-lining residues) and the tetramer (interactions among monomers and a positive cooperative effect).
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Affiliation(s)
- Marcelo Ozu
- Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires C1428EGA, Argentina.
- Instituto de Biodiversidad y Biología Experimental y Aplicada (IBBEA), Universidad de Buenos Aires y Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires C1428EGA CABA, Argentina.
| | - Luciano Galizia
- Instituto de investigaciones Médicas A. Lanari, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires C1427ARO, Argentina.
- Consejo Nacional de Investigaciones Científicas y Técnicas, Laboratorio de Canales Iónicos, Instituto de Investigaciones Médicas (IDIM), Universidad de Buenos Aires, Buenos Aires C1427ARO, Argentina.
| | - Cynthia Acuña
- Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires C1428EGA, Argentina.
- Instituto de Biodiversidad y Biología Experimental y Aplicada (IBBEA), Universidad de Buenos Aires y Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires C1428EGA CABA, Argentina.
| | - Gabriela Amodeo
- Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires C1428EGA, Argentina.
- Instituto de Biodiversidad y Biología Experimental y Aplicada (IBBEA), Universidad de Buenos Aires y Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires C1428EGA CABA, Argentina.
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15
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Uzcátegui NL, Figarella K, Segnini A, Marsiccobetre S, Lang F, Beitz E, Rodríguez-Acosta A, Bertl A. Trypanosoma brucei aquaglyceroporins mediate the transport of metabolic end-products: Methylglyoxal, D-lactate, L-lactate and acetate. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:2252-2261. [DOI: 10.1016/j.bbamem.2018.09.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 08/26/2018] [Accepted: 09/10/2018] [Indexed: 10/28/2022]
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16
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Erler H, Ren B, Gupta N, Beitz E. The intracellular parasite Toxoplasma gondii harbors three druggable FNT-type formate and l-lactate transporters in the plasma membrane. J Biol Chem 2018; 293:17622-17630. [PMID: 30237165 DOI: 10.1074/jbc.ra118.003801] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 09/14/2018] [Indexed: 12/31/2022] Open
Abstract
Toxoplasma gondii is a globally prevalent parasitic protist. It is well-known for its ability to infect almost all nucleated vertebrate cells, which is reflected by its unique metabolic architecture. Its fast-growing tachyzoite stage catabolizes glucose via glycolysis to yield l-lactate as a major by-product that must be exported from the cell to prevent toxicity; the underlying mechanism remains to be elucidated, however. Herein, we report three formate-nitrite transporter (FNT)-type monocarboxylate/proton symporters located in the plasma membrane of the T. gondii tachyzoite stage. We observed that all three proteins transport both l-lactate and formate in a pH-dependent manner and are inhibited by 2-hydroxy-chromanones (a class of small synthetic molecules). We also show that these compounds pharmacologically inhibit T. gondii growth. Using a chemical biology approach, we identified the critical residues in the substrate-selectivity region of the parasite transporters that determine differential specificity and sensitivity toward both substrates and inhibitors. Our findings further indicate that substrate specificity in FNT family proteins from T. gondii has evolved such that a functional repurposing of prokaryotic-type transporters helps fulfill a critical metabolic role in a clinically important parasitic protist. In summary, we have identified and characterized the lactate transporters of T. gondii and have shown that compounds blocking the FNTs in this parasite can inhibit its growth, suggesting that these transporters could have utility as potential drug targets.
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Affiliation(s)
- Holger Erler
- From the Department of Pharmaceutical and Medicinal Chemistry, Christian-Albrechts-University of Kiel, 24118 Kiel, Germany and
| | - Bingjian Ren
- Department of Molecular Parasitology, Faculty of Life Sciences, Humboldt University, 10115 Berlin, Germany
| | - Nishith Gupta
- Department of Molecular Parasitology, Faculty of Life Sciences, Humboldt University, 10115 Berlin, Germany
| | - Eric Beitz
- From the Department of Pharmaceutical and Medicinal Chemistry, Christian-Albrechts-University of Kiel, 24118 Kiel, Germany and
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17
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Hannesschläger C, Barta T, Siligan C, Horner A. Quantification of Water Flux in Vesicular Systems. Sci Rep 2018; 8:8516. [PMID: 29867158 PMCID: PMC5986868 DOI: 10.1038/s41598-018-26946-9] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Accepted: 05/22/2018] [Indexed: 01/29/2023] Open
Abstract
Water transport across lipid membranes is fundamental to all forms of life and plays a major role in health and disease. However, not only typical water facilitators like aquaporins facilitate water flux, but also transporters, ion channels or receptors represent potent water pathways. The efforts directed towards a mechanistic understanding of water conductivity determinants in transmembrane proteins, the development of water flow inhibitors, and the creation of biomimetic membranes with incorporated membrane proteins or artificial water channels depend on reliable and accurate ways of quantifying water permeabilities Pf. A conventional method is to subject vesicles to an osmotic gradient in a stopped-flow device: Fast recordings of scattered light intensity are converted into the time course of vesicle volume change. Even though an analytical solution accurately acquiring Pf from scattered light intensities exists, approximations potentially misjudging Pf by orders of magnitude are used. By means of computational and experimental data we point out that erroneous results such as that the single channel water permeability pf depends on the osmotic gradient are direct results of such approximations. Finally, we propose an empirical solution of which calculated permeability values closely match those calculated with the analytical solution in the relevant range of parameters.
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Affiliation(s)
- Christof Hannesschläger
- Institute of Biophysics, Johannes Kepler University Linz, Gruberstr. 40, 4020, Linz, Austria
| | - Thomas Barta
- Institute of Biophysics, Johannes Kepler University Linz, Gruberstr. 40, 4020, Linz, Austria
| | - Christine Siligan
- Institute of Biophysics, Johannes Kepler University Linz, Gruberstr. 40, 4020, Linz, Austria
| | - Andreas Horner
- Institute of Biophysics, Johannes Kepler University Linz, Gruberstr. 40, 4020, Linz, Austria.
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18
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Meier A, Erler H, Beitz E. Targeting Channels and Transporters in Protozoan Parasite Infections. Front Chem 2018; 6:88. [PMID: 29637069 PMCID: PMC5881087 DOI: 10.3389/fchem.2018.00088] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2018] [Accepted: 03/12/2018] [Indexed: 12/25/2022] Open
Abstract
Infectious diseases caused by pathogenic protozoa are among the most significant causes of death in humans. Therapeutic options are scarce and massively challenged by the emergence of resistant parasite strains. Many of the current anti-parasite drugs target soluble enzymes, generate unspecific oxidative stress, or act by an unresolved mechanism within the parasite. In recent years, collections of drug-like compounds derived from large-scale phenotypic screenings, such as the malaria or pathogen box, have been made available to researchers free of charge boosting the identification of novel promising targets. Remarkably, several of the compound hits have been found to inhibit membrane proteins at the periphery of the parasites, i.e., channels and transporters for ions and metabolites. In this review, we will focus on the progress made on targeting channels and transporters at different levels and the potential for use against infections with apicomplexan parasites mainly Plasmodium spp. (malaria) and Toxoplasma gondii (toxoplasmosis), with kinetoplastids Trypanosoma brucei (sleeping sickness), Trypanosoma cruzi (Chagas disease), and Leishmania ssp. (leishmaniasis), and the amoeba Entamoeba histolytica (amoebiasis).
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Affiliation(s)
- Anna Meier
- Department of Pharmaceutical and Medicinal Chemistry, Christian-Albrechts-University of Kiel, Kiel, Germany
| | - Holger Erler
- Department of Pharmaceutical and Medicinal Chemistry, Christian-Albrechts-University of Kiel, Kiel, Germany
| | - Eric Beitz
- Department of Pharmaceutical and Medicinal Chemistry, Christian-Albrechts-University of Kiel, Kiel, Germany
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19
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MIP diversity from Trichoderma: Structural considerations and transcriptional modulation during mycoparasitic association with Fusarium solani olive trees. PLoS One 2018; 13:e0193760. [PMID: 29543834 PMCID: PMC5854309 DOI: 10.1371/journal.pone.0193760] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 02/17/2018] [Indexed: 11/19/2022] Open
Abstract
Major intrinsic proteins (MIP) are characterized by a transmembrane pore-type architecture that facilitates transport across biomembranes of water and a variety of low molecular weight solutes. They are found in all parts of life, with remarkable protein diversity. Very little is known about MIP from fungi. And yet, it can legitimately be stated that MIP are pivotal molecular components in the privileged relationships fungi enjoy with plants or soil fauna in various environments. To date, MIP have never been studied in a mycoparasitism situation. In this study, the diversity, expression and functional prediction of MIP from the genus Trichoderma were investigated. Trichoderma spp. genomes have at least seven aquaporin genes. Based on a phylogenetic analysis of the translated sequences, members were assigned to the AQP, AQGP and XIP subfamilies. In in vitro and in planta assays with T. harzianum strain Ths97, expression analyses showed that four genes were constitutively expressed. In a mycoparasitic context with Fusarium solani, the causative agent of fusarium dieback on olive tree roots, these genes were up-regulated. This response is of particular interest in analyzing the MIP promoter cis-regulatory motifs, most of which are involved in various carbon and nitrogen metabolisms. Structural analyses provide new insights into the possible role of structural checkpoints by which these members transport water, H2O2, glycerol and, more generally, linear polyols across the membranes. Taken together, these results provide the first evidence that MIP may play a key role in Trichoderma mycoparasitism lifestyle.
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20
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Lu MX, Pan DD, Xu J, Liu Y, Wang GR, Du YZ. Identification and Functional Analysis of the First Aquaporin from Striped Stem Borer, Chilo suppressalis. Front Physiol 2018; 9:57. [PMID: 29467668 PMCID: PMC5808226 DOI: 10.3389/fphys.2018.00057] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 01/17/2018] [Indexed: 01/20/2023] Open
Abstract
Aquaporins are integral membrane proteins some of which form high capacity water-selective channels, promoting water permeation across cell membranes. In this study, we isolated the aquaporin transcript (CsDrip1) of Chilo suppressalis, one of the important rice pests. CsDrip1 included two variants, CsDrip1_v1 and CsDrip1_v2. Although CsDrip1_v2 sequence (>409 bp) was longer than CsDrip1_v1, they possessed the same open reading frame (ORF). Protein structure and topology of CsDrip1 was analyzed using a predicted model, and the results demonstrated the conserved properties of insect water-specific aquaporins, including 6 transmembrane domains, 2 NPA motifs, ar/R constriction region (Phe69, His194, Ser203, and Arg209) and the C-terminal peptide sequence ending in "SYDF." Our data revealed that the Xenopus oocytes expressing CsDrip1 indicated CsDrip1 could transport water instead of glycerol, trehalose and urea. Further, the transcript of CsDrip1 expressed ubiquitously but differentially in different tissues or organs and developmental stages of C. suppressalis. CsDrip1 mRNA exhibited the highest level of expression within hindgut and the third instar larvae. Regardless of pupae and adults, there were significantly different expression levels of CsDrip1 gene between male and female. Different from at low temperature, the transcript of CsDrip1 in larvae exposed to high temperature was increased significantly. Moreover, the mRNA levels of CsDrip1 in the third instar larvae, the fifth instar larvae, pupae (male and female), and adults (male and female) under different humidities were investigated. However, the mRNA levels of CsDrip1 of only female and male adults were changed remarkably. In conclusions, CsDrip1 plays important roles in maintaining water homeostasis in this important rice pest.
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Affiliation(s)
- Ming-Xing Lu
- College of Horticulture and Plant Protection and Institute of Applied Entomology, Yangzhou University, Yangzhou, China.,Jiangsu Key Laboratory of Crop Genetics and Physiology, Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou, China
| | - Dan-Dan Pan
- College of Horticulture and Plant Protection and Institute of Applied Entomology, Yangzhou University, Yangzhou, China.,Jiangsu Key Laboratory of Crop Genetics and Physiology, Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou, China
| | - Jing Xu
- College of Horticulture and Plant Protection and Institute of Applied Entomology, Yangzhou University, Yangzhou, China.,Jiangsu Key Laboratory of Crop Genetics and Physiology, Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou, China
| | - Yang Liu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Gui-Rong Wang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yu-Zhou Du
- College of Horticulture and Plant Protection and Institute of Applied Entomology, Yangzhou University, Yangzhou, China.,Jiangsu Key Laboratory of Crop Genetics and Physiology, Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou, China
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21
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Wiechert M, Erler H, Golldack A, Beitz E. A widened substrate selectivity filter of eukaryotic formate-nitrite transporters enables high-level lactate conductance. FEBS J 2017; 284:2663-2673. [PMID: 28544379 DOI: 10.1111/febs.14117] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Revised: 05/05/2017] [Accepted: 05/18/2017] [Indexed: 12/24/2022]
Abstract
Bacterial formate-nitrite transporters (FNT) regulate the metabolic flow of small weak mono-acids derived from anaerobic mixed-acid fermentation, such as formate, and further transport nitrite and hydrosulfide. The eukaryotic Plasmodium falciparumFNT is vital for the malaria parasite by its ability to release the larger l-lactate substrate as the metabolic end product of anaerobic glycolysis in symport with protons preventing cytosolic acidification. However, the molecular basis for substrate discrimination by FNTs has remained unclear. Here, we identified a size-selective FNT substrate filter region around an invariant lysine at the bottom of the periplasmic/extracellular vestibule. The selectivity filter is reminiscent of the aromatic/arginine constriction of aquaporin water and solute channels regarding composition, location in the protein, and the size-selection principle. Bioinformatics support an adaptation of the eukaryotic FNT selectivity filter to accommodate larger physiologically relevant substrates. Mutations that affect the diameter at the filter site predictably modulated substrate selectivity. The shape of the vestibule immediately above the filter region further affects selectivity. This study indicates that eukaryotic FNTs evolved to transport larger mono-acid substrates, especially l-lactic acid as a product of energy metabolism.
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Affiliation(s)
- Marie Wiechert
- Department of Pharmaceutical and Medicinal Chemistry, Christian-Albrechts-University of Kiel, Germany
| | - Holger Erler
- Department of Pharmaceutical and Medicinal Chemistry, Christian-Albrechts-University of Kiel, Germany
| | - André Golldack
- Department of Pharmaceutical and Medicinal Chemistry, Christian-Albrechts-University of Kiel, Germany
| | - Eric Beitz
- Department of Pharmaceutical and Medicinal Chemistry, Christian-Albrechts-University of Kiel, Germany
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22
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Ni ZX, Cui JM, Zhang NZ, Fu BQ. Structural and evolutionary divergence of aquaporins in parasites (Review). Mol Med Rep 2017; 15:3943-3948. [PMID: 28440467 PMCID: PMC5436202 DOI: 10.3892/mmr.2017.6505] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 02/28/2017] [Indexed: 11/05/2022] Open
Abstract
Aquaporins are ubiquitous proteins that belong to the major intrinsic protein family. Previous studies have indicated that aquaporins are involved in multiple physiological processes in parasites, such as nutrient absorption and end product efflux, and thus, would be promising pharmacological agents in the fight against parasite infection. In the present paper, the authors analyzed the evolutionary relationship of parasitic aquaporins by re‑constructing of a phylogenic tree using neighbor‑joining and maximum likelihood methods. In addition, the authors discussed the variation of the conserved functional sites impacting on the transportation of water molecules. The protein was concluded to be a potential drug target in parasites.
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Affiliation(s)
- Zi-Xin Ni
- College of Veterinary Medicine, China Agricultural University, Beijing 100083, P.R. China
| | - Jian-Min Cui
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu 730046, P.R. China
| | - Nian-Zhang Zhang
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu 730046, P.R. China
| | - Bao-Quan Fu
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu 730046, P.R. China
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23
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Rothert M, Rönfeldt D, Beitz E. Electrostatic attraction of weak monoacid anions increases probability for protonation and passage through aquaporins. J Biol Chem 2017; 292:9358-9364. [PMID: 28360107 DOI: 10.1074/jbc.m117.782516] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Revised: 03/28/2017] [Indexed: 11/06/2022] Open
Abstract
A positive electrostatic field emanating from the center of the aquaporin (AQP) water and solute channel is responsible for the repulsion of cations. At the same time, however, a positive field will attract anions. In this regard, l-lactate/lactic acid permeability has been shown for various isoforms of the otherwise highly water and neutral substrate selective AQP family. The structural requirements rendering certain AQPs permeable for weak monoacids and the mechanism of conduction have remained unclear. Here, we show by profiling pH-dependent substrate permeability, measurements of media alkalization, and proton decoupling that AQP9 acts as a channel for the protonated, neutral monocarboxylic acid species. Intriguingly, the obtained permeability rates indicate an up to 10 times higher probability of passage via AQP9 than given by the fraction of the protonated acid substrate at a certain pH. We generated AQP9 point mutants showing that this effect is independent from properties of the channel interior but caused by the protein surface electrostatics. Monocarboxylic acid-conducting AQPs thus employ a mechanism similar to the family of formate-nitrite transporters for weak monoacids. On a more general basis, our data illustrate semiquantitatively the contribution of surface electrostatics to the interaction of charged molecule substrates or ligands with target proteins, such as channels, transporters, enzymes, or receptors.
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Affiliation(s)
- Monja Rothert
- From the Department of Pharmaceutical and Medicinal Chemistry, Christian-Albrechts-University of Kiel, 24118 Kiel, Germany
| | - Deike Rönfeldt
- From the Department of Pharmaceutical and Medicinal Chemistry, Christian-Albrechts-University of Kiel, 24118 Kiel, Germany
| | - Eric Beitz
- From the Department of Pharmaceutical and Medicinal Chemistry, Christian-Albrechts-University of Kiel, 24118 Kiel, Germany
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24
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Chng YR, Ong JLY, Ching B, Chen XL, Hiong KC, Wong WP, Chew SF, Lam SH, Ip YK. Molecular Characterization of Aquaporin 1 and Aquaporin 3 from the Gills of the African Lungfish, Protopterus annectens, and Changes in Their Branchial mRNA Expression Levels and Protein Abundance during Three Phases of Aestivation. Front Physiol 2016; 7:532. [PMID: 27891097 PMCID: PMC5102888 DOI: 10.3389/fphys.2016.00532] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 10/25/2016] [Indexed: 01/07/2023] Open
Abstract
African lungfishes can undergo long periods of aestivation on land during drought. During aestivation, lungfishes are confronted with desiccation and dehydration, and their gills become non-functional and covered with a thick layer of dried mucus. Aquaporins (Aqps) are a superfamily of integral membrane proteins which generally facilitate the permeation of water through plasma membranes. This study aimed to obtain the complete cDNA coding sequences of aqp1 and aqp3 from the gills of Protopterus annectens, and to determine their branchial mRNA and protein expression levels during the induction, maintenance and arousal phases of aestivation. Dendrogramic analyses of the deduced Aqp1 and Aqp3 amino acid sequences of P. annectens revealed their close relationships with those of Latimeria chalumnae and tetrapods. During the induction phase, there were significant decreases in the transcript levels of aqp1 and aqp3 in the gills of P. annectens, but the branchial Aqp1 and Aqp3 protein abundance remained unchanged. As changes in transcription might precede changes in translation, this could be regarded as an adaptive response to decrease the protein abundance of Aqp1 and Aqp3 in the subsequent maintenance phase of aestivation. As expected, the branchial transcript levels and protein abundance of aqp1/Aqp1 and aqp3/Aqp3 were significantly down-regulated during the maintenance phase, probably attributable to the shutdown of branchial functions and the cessation of volume regulation of branchial epithelial cells. Additionally, these changes could reduce the loss of water through branchial epithelial surfaces, supplementing the anti-desiccating property of the dried mucus. Upon arousal, it was essential for the lungfish to restore branchial functions. Indeed, the protein abundance of Aqp1 recovered partially, with complete recovery of mRNA expression level and protein abundance of Aqp3, in the gills of P. annectens after 3 days of arousal. These results provide insights into how P. annectens regulates branchial Aqp expression to cope with desiccation and rehydration during different phases of aestivation.
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Affiliation(s)
- You R. Chng
- Department of Biological Sciences, National University of SingaporeSingapore, Singapore
| | - Jasmine L. Y. Ong
- Department of Biological Sciences, National University of SingaporeSingapore, Singapore
| | - Biyun Ching
- Department of Biological Sciences, National University of SingaporeSingapore, Singapore
| | - Xiu L. Chen
- Department of Biological Sciences, National University of SingaporeSingapore, Singapore
| | - Kum C. Hiong
- Department of Biological Sciences, National University of SingaporeSingapore, Singapore
| | - Wai P. Wong
- Department of Biological Sciences, National University of SingaporeSingapore, Singapore
| | - Shit F. Chew
- Natural Sciences and Science Education, National Institute of Education, Nanyang Technological UniversitySingapore, Singapore
| | - Siew H. Lam
- Department of Biological Sciences, National University of SingaporeSingapore, Singapore
- NUS Environmental Research Institute, National University of SingaporeSingapore, Singapore
| | - Yuen K. Ip
- Department of Biological Sciences, National University of SingaporeSingapore, Singapore
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Pérez Di Giorgio JA, Soto GC, Muschietti JP, Amodeo G. Pollen Aquaporins: The Solute Factor. FRONTIERS IN PLANT SCIENCE 2016; 7:1659. [PMID: 27881985 PMCID: PMC5101680 DOI: 10.3389/fpls.2016.01659] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 10/21/2016] [Indexed: 05/12/2023]
Abstract
In the recent years, the biophysical properties and presumed physiological role of aquaporins (AQPs) have been expanded to specialized cells where water and solute exchange are crucial traits. Complex but unique processes such as stomatal movement or pollen hydration and germination have been addressed not only by identifying the specific AQP involved but also by studying how these proteins integrate and coordinate cellular activities and functions. In this review, we referred specifically to pollen-specific AQPs and analyzed what has been assumed in terms of transport properties and what has been found in terms of their physiological role. Unlike that in many other cells, the AQP machinery in mature pollen lacks plasma membrane intrinsic proteins, which are extensively studied for their high water capacity exchange. Instead, a variety of TIPs and NIPs are expressed in pollen. These findings have altered the initial understanding of AQPs and water exchange to consider specific and diverse solutes that might be critical to sustaining pollen's success. The spatial and temporal distribution of the pollen AQPs also reflects a regulatory mechanism that allowing a properly adjusting water and solute exchange.
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Affiliation(s)
- Juliana A. Pérez Di Giorgio
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular – Consejo Nacional de Investigaciones Científicas y TécnicasBuenos Aires, Argentina
| | - Gabriela C. Soto
- Instituto de Genética Ewald A. Favret – Centro de Investigación en Ciencias Veterinarias y Agronómicas – Instituto Nacional de Tecnología Agropecuaria – Consejo Nacional de Investigaciones Científicas y TécnicasBuenos Aires, Argentina
| | - Jorge P. Muschietti
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular – Consejo Nacional de Investigaciones Científicas y TécnicasBuenos Aires, Argentina
- Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos AiresBuenos Aires, Argentina
| | - Gabriela Amodeo
- Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos AiresBuenos Aires, Argentina
- Instituto de Biodiversidad y Biología Experimental y Aplicada – Universidad de Buenos Aires–Consejo Nacional de Investigaciones Científicas y TécnicasBuenos Aires, Argentina
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Sreedharan S, Kothandan G, Sankaranarayanan K. Structural insights into the Aedes aegypti aquaporins and aquaglyceroporins – an in silico study. J Recept Signal Transduct Res 2016; 36:543-557. [DOI: 10.3109/10799893.2016.1141954] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Sandhya Sreedharan
- AU-KBC Research Centre, Madras Institute of Technology, Anna University, Chennai, India and
| | - Gugan Kothandan
- Centre for Advanced Study in Crystallography and Biophysics, Guindy Campus, University of Madras, Chennai, India
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Song J, Baker N, Rothert M, Henke B, Jeacock L, Horn D, Beitz E. Pentamidine Is Not a Permeant but a Nanomolar Inhibitor of the Trypanosoma brucei Aquaglyceroporin-2. PLoS Pathog 2016; 12:e1005436. [PMID: 26828608 PMCID: PMC4734766 DOI: 10.1371/journal.ppat.1005436] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 01/12/2016] [Indexed: 11/19/2022] Open
Abstract
The chemotherapeutic arsenal against human African trypanosomiasis, sleeping sickness, is limited and can cause severe, often fatal, side effects. One of the classic and most widely used drugs is pentamidine, an aromatic diamidine compound introduced in the 1940s. Recently, a genome-wide loss-of-function screen and a subsequently generated trypanosome knockout strain revealed a specific aquaglyceroporin, TbAQP2, to be required for high-affinity uptake of pentamidine. Yet, the underlying mechanism remained unclear. Here, we show that TbAQP2 is not a direct transporter for the di-basic, positively charged pentamidine. Even though one of the two common cation filters of aquaglyceroporins, i.e. the aromatic/arginine selectivity filter, is unconventional in TbAQP2, positively charged compounds are still excluded from passing the channel. We found, instead, that the unique selectivity filter layout renders pentamidine a nanomolar inhibitor of TbAQP2 glycerol permeability. Full, non-covalent inhibition of an aqua(glycero)porin in the nanomolar range has not been achieved before. The remarkable affinity derives from an electrostatic interaction with Asp265 and shielding from water as shown by structure-function evaluation and point mutation of Asp265. Exchange of the preceding Leu264 to arginine abolished pentamidine-binding and parasites expressing this mutant were pentamidine-resistant. Our results indicate that TbAQP2 is a high-affinity receptor for pentamidine. Taken together with localization of TbAQP2 in the flagellar pocket of bloodstream trypanosomes, we propose that pentamidine uptake is by endocytosis.
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Affiliation(s)
- Jie Song
- Department of Pharmaceutical and Medicinal Chemistry, Christian-Albrechts-University of Kiel, Kiel, Germany
| | - Nicola Baker
- Division of Biological Chemistry & Drug Discovery, School of Life Sciences, University of Dundee, Dundee, Scotland, United Kingdom
| | - Monja Rothert
- Department of Pharmaceutical and Medicinal Chemistry, Christian-Albrechts-University of Kiel, Kiel, Germany
| | - Björn Henke
- Department of Pharmaceutical and Medicinal Chemistry, Christian-Albrechts-University of Kiel, Kiel, Germany
| | - Laura Jeacock
- Division of Biological Chemistry & Drug Discovery, School of Life Sciences, University of Dundee, Dundee, Scotland, United Kingdom
| | - David Horn
- Division of Biological Chemistry & Drug Discovery, School of Life Sciences, University of Dundee, Dundee, Scotland, United Kingdom
| | - Eric Beitz
- Department of Pharmaceutical and Medicinal Chemistry, Christian-Albrechts-University of Kiel, Kiel, Germany
- * E-mail:
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Genes CM, de Lucio H, González VM, Sánchez-Murcia PA, Rico E, Gago F, Fasel N, Jiménez-Ruiz A. A functional BH3 domain in an aquaporin from Leishmania infantum. Cell Death Discov 2016; 2:16043. [PMID: 27551533 PMCID: PMC4979448 DOI: 10.1038/cddiscovery.2016.43] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Accepted: 05/15/2016] [Indexed: 02/08/2023] Open
Abstract
Despite the absence of sequences showing significant similarity to any of the members of the Bcl-2 family of proteins in protozoa, experiments carried out in yeast or trypanosomatids have demonstrated that ectopic expression of some of these members alters their response to different death stimuli. Because the BH3 domain is the smallest common signature in all the proteins of this family of apoptosis regulators and also because they are essential for molecular interactions between antagonistic members, we looked for sequences with significant similarity to the BH3 motif in the Leishmania infantum genome. Among the top scoring ones, we found the MYLALQNLGDEV amino-acid stretch at the C terminus of a previously described aquaporin, now renamed as Li-BH3AQP. This motif is highly conserved in homologous proteins from other species of the Leishmania genus. The association of Li-BH3AQP with human Bcl-XL was demonstrated by both co-immunoprecipitation and yeast two-hybrid experiments. Ectopic expression of Li-BH3AQP reduced viability of HeLa cells and this deleterious effect was abrogated by the simultaneous overexpression of Bcl-XL. Although we were not able to demonstrate a reduction in parasite viability when the protein was overexpressed in Leishmania promastigotes, a prodeath effect could be observed when the parasites overexpressing Li-BH3AQP were treated with staurosporine or antimycin A. Surprisingly, these parasites were more resistant, compared with wild-type parasites, to hypotonic stress or nutrient deprivation. The prodeath activity was abolished upon replacement of two highly conserved amino acids in this BH3 domain. Taken together, these results point to Li-BH3AQP as the first non-enzymatic protein ever described in trypanosomatids that is involved in cell death.
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Affiliation(s)
- C M Genes
- Departamento de Biología de Sistemas, Universidad de Alcalá, Alcalá de Henares 28805, Spain
| | - H de Lucio
- Departamento de Biología de Sistemas, Universidad de Alcalá, Alcalá de Henares 28805, Spain
| | - V M González
- Laboratory of aptamers, Departamento de Bioquímica-Investigación, IRYCIS-Hospital Ramón y Cajal, Madrid, Spain
| | - P A Sánchez-Murcia
- Departamento de Ciencias Biomédicas, Universidad de Alcalá, Facultad de Medicina, Alcalá de Henares 28805, Spain
| | - E Rico
- Departamento de Biología de Sistemas, Universidad de Alcalá, Alcalá de Henares 28805, Spain
| | - F Gago
- Departamento de Ciencias Biomédicas, Universidad de Alcalá, Facultad de Medicina, Alcalá de Henares 28805, Spain
| | - N Fasel
- Department of Biochemistry, University of Lausanne, 155 Chemin des Boveresses, Epalinges 1066, Switzerland
| | - A Jiménez-Ruiz
- Departamento de Biología de Sistemas, Universidad de Alcalá, Alcalá de Henares 28805, Spain
- ()
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Kreida S, Törnroth-Horsefield S. Structural insights into aquaporin selectivity and regulation. Curr Opin Struct Biol 2015; 33:126-34. [PMID: 26342685 DOI: 10.1016/j.sbi.2015.08.004] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Revised: 08/05/2015] [Accepted: 08/07/2015] [Indexed: 11/26/2022]
Abstract
Aquaporins have emerged as one of the structurally best-characterized membrane protein families, with fourteen different structures available from a diverse range of organisms. While all aquaporins share the same fold and passive mechanism for water permeation, structural details allow for differences in selectivity and modes of regulation. These details are now the emphasis of aquaporin structural biology. Recent structural studies of eukaryotic aquaporins have revealed reoccurring structural themes in both gating and trafficking, implying a limited number of structural solutions to aquaporin regulation. Moreover, the groundbreaking subangstrom resolution structure of a yeast aquaporin allows hydrogens to be visualized in the water-conducting channel, providing exclusive new insights into the proton exclusion mechanism.
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Affiliation(s)
- Stefan Kreida
- Department of Biochemistry and Structural Biology, Centre for Protein Molecular Science, Lund University, Lund, Sweden
| | - Susanna Törnroth-Horsefield
- Department of Biochemistry and Structural Biology, Centre for Protein Molecular Science, Lund University, Lund, Sweden.
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Beitz E, Golldack A, Rothert M, von Bülow J. Challenges and achievements in the therapeutic modulation of aquaporin functionality. Pharmacol Ther 2015; 155:22-35. [PMID: 26277280 DOI: 10.1016/j.pharmthera.2015.08.002] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Aquaporin (AQP) water and solute channels have basic physiological functions throughout the human body. AQP-facilitated water permeability across cell membranes is required for rapid reabsorption of water from pre-urine in the kidneys and for sustained near isosmolar water fluxes e.g. in the brain, eyes, inner ear, and lungs. Cellular water permeability is further connected to cell motility. AQPs of the aquaglyceroporin subfamily are necessary for lipid degradation in adipocytes and glycerol uptake into the liver, as well as for skin moistening. Modulation of AQP function is desirable in several pathophysiological situations, such as nephrogenic diabetes insipidus, Sjögren's syndrome, Menière's disease, heart failure, or tumors to name a few. Attempts to design or to find effective small molecule AQP inhibitors have yielded only a few hits. Challenges reside in the high copy number of AQP proteins in the cell membranes, and spatial restrictions in the protein structure. This review gives an overview on selected physiological and pathophysiological conditions in which modulation of AQP functions appears beneficial and discusses first achievements in the search of drug-like AQP inhibitors.
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Affiliation(s)
- Eric Beitz
- Pharmaceutical and Medicinal Chemistry, University of Kiel, Germany.
| | - André Golldack
- Pharmaceutical and Medicinal Chemistry, University of Kiel, Germany
| | - Monja Rothert
- Pharmaceutical and Medicinal Chemistry, University of Kiel, Germany
| | - Julia von Bülow
- Pharmaceutical and Medicinal Chemistry, University of Kiel, Germany
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Abstract
In this review, we provide a brief synopsis of the evolution and functional diversity of the aquaporin gene superfamily in prokaryotic and eukaryotic organisms. Based upon the latest data, we discuss the expanding list of molecules shown to permeate the central pore of aquaporins, and the unexpected diversity of water channel genes in Archaea and Bacteria. We further provide new insight into the origin by horizontal gene transfer of plant glycerol-transporting aquaporins (NIPs), and the functional co-option and gene replacement of insect glycerol transporters. Finally, we discuss the origins of four major grades of aquaporins in Eukaryota, together with the increasing repertoires of aquaporins in vertebrates.
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Affiliation(s)
- Roderick Nigel Finn
- Department of Biology, Bergen High Technology Centre, University of Bergen, Norway; Institute of Marine Research, Nordnes, 5817 Bergen, Norway; and
| | - Joan Cerdà
- Institut de Recerca i Tecnologia Agroalimentàries (IRTA)-Institut de Ciències del Mar, Consejo Superior de Investigaciones Científicas (CSIC), 08003 Barcelona, Spain
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Krenc D, Song J, Almasalmeh A, Wu B, Beitz E. The arginine-facing amino acid residue of the rat aquaporin 1 constriction determines solute selectivity according to its size and lipophilicity. Mol Membr Biol 2014; 31:228-38. [DOI: 10.3109/09687688.2014.960493] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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Rambow J, Wu B, Rönfeldt D, Beitz E. Aquaporins with anion/monocarboxylate permeability: mechanisms, relevance for pathogen-host interactions. Front Pharmacol 2014; 5:199. [PMID: 25225485 PMCID: PMC4150397 DOI: 10.3389/fphar.2014.00199] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Accepted: 08/12/2014] [Indexed: 11/22/2022] Open
Abstract
Classically, aquaporins are divided based on pore selectivity into water specific, orthodox aquaporins and solute-facilitating aquaglyceroporins, which conduct, e.g., glycerol and urea. However, more aquaporin-passing substrates have been identified over the years, such as the gasses ammonia and carbon dioxide or the water-related hydrogen peroxide. It became apparent that not all aquaporins clearly fit into one of only two subfamilies. Furthermore, certain aquaporins from both major subfamilies have been reported to conduct inorganic anions, such as chloride, or monoacids/monocarboxylates, such as lactic acid/lactate. Here, we summarize the findings on aquaporin anion transport, analyze the pore layout of such aquaporins in comparison to prototypical non-selective anion channels, monocarboxylate transporters, and formate–nitrite transporters. Finally, we discuss in which scenarios anion conducting aquaporins may be of physiological relevance.
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Affiliation(s)
- Janis Rambow
- Department of Pharmaceutical and Medicinal Chemistry, Christian-Albrechts-University of Kiel Kiel, Germany
| | - Binghua Wu
- Department of Pharmaceutical and Medicinal Chemistry, Christian-Albrechts-University of Kiel Kiel, Germany
| | - Deike Rönfeldt
- Department of Pharmaceutical and Medicinal Chemistry, Christian-Albrechts-University of Kiel Kiel, Germany
| | - Eric Beitz
- Department of Pharmaceutical and Medicinal Chemistry, Christian-Albrechts-University of Kiel Kiel, Germany
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Parasite aquaporins: Current developments in drug facilitation and resistance. Biochim Biophys Acta Gen Subj 2014; 1840:1566-73. [DOI: 10.1016/j.bbagen.2013.10.014] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Revised: 10/02/2013] [Accepted: 10/06/2013] [Indexed: 01/15/2023]
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Abstract
Members of the urea transporter (UT) family mediate rapid, selective transport of urea down its concentration gradient. To date, crystal structures of two evolutionarily distant UTs have been solved. These structures reveal a common UT fold involving two structurally homologous domains that encircle a continuous membrane-spanning pore and indicate that UTs transport urea via a channel-like mechanism. Examination of the conserved architecture of the pore, combined with crystal structures of ligand-bound proteins, molecular dynamics simulations, and functional data on permeation and inhibition by a broad range of urea analogs and other small molecules, provides insight into the structural basis of urea permeation and selectivity.
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Affiliation(s)
- Elena J. Levin
- Department of Biochemistry and Molecular Biology, Baylor College of Medicine 1 Baylor Plaza, Houston, TX 77030 USA
| | - Ming Zhou
- Department of Biochemistry and Molecular Biology, Baylor College of Medicine 1 Baylor Plaza, Houston, TX 77030 USA
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Tani K, Fujiyoshi Y. Water channel structures analysed by electron crystallography. Biochim Biophys Acta Gen Subj 2013; 1840:1605-13. [PMID: 24120524 DOI: 10.1016/j.bbagen.2013.10.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Revised: 09/30/2013] [Accepted: 10/03/2013] [Indexed: 11/17/2022]
Abstract
BACKGROUND The mechanisms underlying water transport through aquaporin (AQP) have been debated for two decades. The water permeation phenomenon of AQP seems inexplicable because the Grotthuss mechanism does not allow for simultaneous fast water permeability and inhibition of proton transfer through the hydrogen bonds of water molecules. SCOPE OF REVIEW The AQP1 structure determined by electron crystallography provided the first insights into the proton exclusion mechanism despite fast water permeation. Although several studies have provided clues about the mechanism based on the AQP structure, each proposed mechanism remains incomplete. The present review is focused on AQP function and structure solved by electron crystallography in an attempt to fill the gaps between the findings in the absence and presence of lipids. MAJOR CONCLUSIONS Many AQP structures can be superimposed regardless of the determination method. The AQP fold is preserved even under conditions lacking lipids, but the water arrangement in the channel pore differs. The differences might be explained by dipole moments formed by the two short helices in the lipid bilayer. In addition, structure analyses of double-layered two-dimensional crystals of AQP suggest an array formation and cell adhesive function. GENERAL SIGNIFICANCE Electron crystallography findings not only have contributed to resolve some of the water permeation mechanisms, but have also elucidated the multiple functions of AQPs in the membrane. The roles of AQPs in the brain remain obscure, but their multiple activities might be important in the regulation of brain and other biological functions. This article is part of a Special Issue entitled Aquaporins.
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Affiliation(s)
- Kazutoshi Tani
- Cellular and Structural Physiology Institute, Nagoya University, Furo-cho, Chikusa, Nagoya, Japan
| | - Yoshinori Fujiyoshi
- Cellular and Structural Physiology Institute, Nagoya University, Furo-cho, Chikusa, Nagoya, Japan.
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Clemens DM, Németh-Cahalan KL, Trinh L, Zhang T, Schilling TF, Hall JE. In vivo analysis of aquaporin 0 function in zebrafish: permeability regulation is required for lens transparency. Invest Ophthalmol Vis Sci 2013; 54:5136-43. [PMID: 23800763 DOI: 10.1167/iovs.13-12337] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE The zebrafish lens is well suited for studies of physiology and development due to its rapid formation in the embryo and genetic accessibility. Aquaporin 0 (AQP0), a lens-specific membrane protein, is required for lens clarity. Zebrafish have two copies of AQP0 (Aqp0a and b), whereas mammals have a single, multifunctional protein. Here we demonstrate a reliable knockdown/rescue system in zebrafish and use it to provide evidence for subfunctionalization of Aqp0a and b, as well as to show that calcium-mediated regulation of Aqp0a in zebrafish lenses is necessary for transparency. METHODS Coinjection of antisense oligonucleotides and DNA rescue constructs into zebrafish embryos, followed by evaluation of the developing fish for cataracts, was used to analyze the functions of Aqp0a and b. The water permeability and regulation characteristics of each rescue protein were tested in a Xenopus oocyte swelling assay. RESULTS Both copies of AQP0 are necessary for lens clarity in the zebrafish, and neither is sufficient. Water permeability is necessary but also insufficient. Phosphorylation and regulation of Aqp0a are required for its function. CONCLUSIONS In the zebrafish lens, the two closely related AQP0s have acquired distinct functions that are both necessary for lens development and clarity. Regulation of AQP0 water permeability, a well-studied phenomenon in vitro, may be physiologically relevant in the living lens.
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Affiliation(s)
- Daniel M Clemens
- Department of Physiology and Biophysics, University of California, Irvine, Irvine, California 92697-4561, USA
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Eriksson UK, Fischer G, Friemann R, Enkavi G, Tajkhorshid E, Neutze R. Subangstrom resolution X-ray structure details aquaporin-water interactions. Science 2013; 340:1346-1349. [PMID: 23766328 DOI: 10.1126/science.1234306] [Citation(s) in RCA: 151] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Aquaporins are membrane channels that facilitate the flow of water across biological membranes. Two conserved regions are central for selective function: the dual asparagine-proline-alanine (NPA) aquaporin signature motif and the aromatic and arginine selectivity filter (SF). Here, we present the crystal structure of a yeast aquaporin at 0.88 angstrom resolution. We visualize the H-bond donor interactions of the NPA motif's asparagine residues to passing water molecules; observe a polarized water-water H-bond configuration within the channel; assign the tautomeric states of the SF histidine and arginine residues; and observe four SF water positions too closely spaced to be simultaneously occupied. Strongly correlated movements break the connectivity of SF waters to other water molecules within the channel and prevent proton transport via a Grotthuss mechanism.
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Affiliation(s)
- Urszula Kosinska Eriksson
- Department of Chemistry and Molecular Biology, University of Gothenburg, Box 462, S-40530 Göteborg, Sweden
| | - Gerhard Fischer
- Department of Chemistry and Molecular Biology, University of Gothenburg, Box 462, S-40530 Göteborg, Sweden
| | - Rosmarie Friemann
- Department of Chemistry and Molecular Biology, University of Gothenburg, Box 462, S-40530 Göteborg, Sweden
| | - Giray Enkavi
- Department of Biochemistry, College of Medicine, Center for Biophysics and Computational Biology, and Beckman Institute for Advanced Science and Technology, University of Illinois, Urbana, Illinois 61802, USA
| | - Emad Tajkhorshid
- Department of Biochemistry, College of Medicine, Center for Biophysics and Computational Biology, and Beckman Institute for Advanced Science and Technology, University of Illinois, Urbana, Illinois 61802, USA
| | - Richard Neutze
- Department of Chemistry and Molecular Biology, University of Gothenburg, Box 462, S-40530 Göteborg, Sweden
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Vilas GL, Loganathan SK, Liu J, Riau AK, Young JD, Mehta JS, Vithana EN, Casey JR. Transmembrane water-flux through SLC4A11: a route defective in genetic corneal diseases. Hum Mol Genet 2013; 22:4579-90. [PMID: 23813972 PMCID: PMC3889808 DOI: 10.1093/hmg/ddt307] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Three genetic corneal dystrophies [congenital hereditary endothelial dystrophy type 2 (CHED2), Harboyan syndrome and Fuchs endothelial corneal dystrophy] arise from mutations of the SLC4a11 gene, which cause blindness from fluid accumulation in the corneal stroma. Selective transmembrane water conductance controls cell size, renal fluid reabsorption and cell division. All known water-channelling proteins belong to the major intrinsic protein family, exemplified by aquaporins (AQPs). Here we identified SLC4A11, a member of the solute carrier family 4 of bicarbonate transporters, as an unexpected addition to known transmembrane water movement facilitators. The rate of osmotic-gradient driven cell-swelling was monitored in Xenopus laevis oocytes and HEK293 cells, expressing human AQP1, NIP5;1 (a water channel protein from plant), hCNT3 (a human nucleoside transporter) and human SLC4A11. hCNT3-expressing cells swelled no faster than control cells, whereas SLC4A11-mediated water permeation at a rate about half that of some AQP proteins. SLC4A11-mediated water movement was: (i) similar to some AQPs in rate; (ii) uncoupled from solute-flux; (iii) inhibited by stilbene disulfonates (classical SLC4 inhibitors); (iv) inactivated in one CHED2 mutant (R125H). Localization of AQP1 and SLC4A11 in human and murine corneal (apical and basolateral, respectively) suggests a cooperative role in mediating trans-endothelial water reabsorption. Slc4a11(-/-) mice manifest corneal oedema and distorted endothelial cells, consistent with loss of a water-flux. Observed water-flux through SLC4A11 extends the repertoire of known water movement pathways and call for a re-examination of explanations for water movement in human tissues.
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Affiliation(s)
- Gonzalo L Vilas
- Membrane Protein Disease Research Group, Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
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Grohme MA, Mali B, Wełnicz W, Michel S, Schill RO, Frohme M. The Aquaporin Channel Repertoire of the Tardigrade Milnesium tardigradum. Bioinform Biol Insights 2013; 7:153-65. [PMID: 23761966 PMCID: PMC3666991 DOI: 10.4137/bbi.s11497] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Limno-terrestrial tardigrades are small invertebrates that are subjected to periodic drought of their micro-environment. They have evolved to cope with these unfavorable conditions by anhydrobiosis, an ametabolic state of low cellular water. During drying and rehydration, tardigrades go through drastic changes in cellular water content. By our transcriptome sequencing effort of the limno-terrestrial tardigrade Milnesium tardigradum and by a combination of cloning and targeted sequence assembly, we identified transcripts encoding eleven putative aquaporins. Analysis of these sequences proposed 2 classical aquaporins, 8 aquaglyceroporins and a single potentially intracellular unorthodox aquaporin. Using quantitative real-time PCR we analyzed aquaporin transcript expression in the anhydrobiotic context. We have identified additional unorthodox aquaporins in various insect genomes and have identified a novel common conserved structural feature in these proteins. Analysis of the genomic organization of insect aquaporin genes revealed several conserved gene clusters.
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Affiliation(s)
- Markus A Grohme
- Molecular Biotechnology and Functional Genomics, Technical University of Applied Sciences Wildau, Wildau, Germany
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41
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Song J, Almasalmeh A, Krenc D, Beitz E. Molar concentrations of sorbitol and polyethylene glycol inhibit the Plasmodium aquaglyceroporin but not that of E. coli: involvement of the channel vestibules. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1818:1218-24. [PMID: 22326891 DOI: 10.1016/j.bbamem.2012.01.025] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Revised: 01/24/2012] [Accepted: 01/25/2012] [Indexed: 11/25/2022]
Abstract
The aquaglyceroporins of Escherichia coli, EcGlpF, and of Plasmodium falciparum, PfAQP, are probably the best characterized members of the solute-conducting aquaporin (AQP) subfamily. Their crystal structures have been elucidated and numerous experimental and theoretical analyses have been conducted. However, opposing reports on their rates of water permeability require clarification. Hence, we expressed EcGlpF and PfAQP in yeast, prepared protoplasts, and compared water and glycerol permeability of both aquaglyceroporins in the presence of different osmolytes, i.e. sucrose, sorbitol, PEG300, and glycerol. We found that water permeability of PfAQP strongly depends on the external osmolyte, with full inhibition by sorbitol, and increasing water permeability when glycerol, PEG300, and sucrose were used. EcGlpF expression did not enhance water permeability over that of non-expressing control protoplasts regardless of the osmolyte. Glycerol permeability of PfAQP was also inhibited by sorbitol, but to a smaller extent, whereas EcGlpF conducted glycerol independently of the osmolyte. Mixtures of glycerol and urea passed PfAQP equally well under isosmotic conditions, whereas under hypertonic conditions in a countercurrent with water, glycerol was clearly preferred over urea. We conclude that PfAQP has high and EcGlpF low water permeability, and explain the inhibiting effect of sorbitol on PfAQP by its binding to the extracellular vestibule. The preference for glycerol under hypertonic conditions implies that in a physiological setting, PfAQP mainly acts as a water/glycerol channel rather than a urea facilitator.
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Affiliation(s)
- Jie Song
- Department of Medicinal amd Pharmaceutical Chemistry, University of Kiel, Gutenbergstrasse 76, 24118, Kiel, Germany
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Gupta AB, Verma RK, Agarwal V, Vajpai M, Bansal V, Sankararamakrishnan R. MIPModDB: a central resource for the superfamily of major intrinsic proteins. Nucleic Acids Res 2012; 40:D362-9. [PMID: 22080560 PMCID: PMC3245135 DOI: 10.1093/nar/gkr914] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2011] [Revised: 10/05/2011] [Accepted: 10/08/2011] [Indexed: 12/23/2022] Open
Abstract
The channel proteins belonging to the major intrinsic proteins (MIP) superfamily are diverse and are found in all forms of life. Water-transporting aquaporin and glycerol-specific aquaglyceroporin are the prototype members of the MIP superfamily. MIPs have also been shown to transport other neutral molecules and gases across the membrane. They have internal homology and possess conserved sequence motifs. By analyzing a large number of publicly available genome sequences, we have identified more than 1000 MIPs from diverse organisms. We have developed a database MIPModDB which will be a unified resource for all MIPs. For each MIP entry, this database contains information about the source, gene structure, sequence features, substitutions in the conserved NPA motifs, structural model, the residues forming the selectivity filter and channel radius profile. For selected set of MIPs, it is possible to derive structure-based sequence alignment and evolutionary relationship. Sequences and structures of selected MIPs can be downloaded from MIPModDB database which is freely available at http://bioinfo.iitk.ac.in/MIPModDB.
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Affiliation(s)
- Anjali Bansal Gupta
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, Kanpur 208016 and Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee 247667, India
| | - Ravi Kumar Verma
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, Kanpur 208016 and Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee 247667, India
| | - Vatsal Agarwal
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, Kanpur 208016 and Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee 247667, India
| | - Manu Vajpai
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, Kanpur 208016 and Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee 247667, India
| | - Vivek Bansal
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, Kanpur 208016 and Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee 247667, India
| | - Ramasubbu Sankararamakrishnan
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, Kanpur 208016 and Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee 247667, India
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