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Yepes-Molina L, Teruel JA, Johanson U, Carvajal M. Brassica oleracea L. var. italica Aquaporin Reconstituted Proteoliposomes as Nanosystems for Resveratrol Encapsulation. Int J Mol Sci 2024; 25:1987. [PMID: 38396666 PMCID: PMC10888208 DOI: 10.3390/ijms25041987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Revised: 02/02/2024] [Accepted: 02/03/2024] [Indexed: 02/25/2024] Open
Abstract
Aquaporins (AQPs), membrane proteins responsible for facilitating water transport, found in plant membrane vesicles (MV), have been related to the functionality and stability of MV. We focused on AQPs obtained from broccoli, as they show potential for biotechnological applications. To gain further insight into the role of AQPs in MV, we describe the heterologous overexpression of two broccoli AQPs (BoPIP1;2 and BoPIP2;2) in Pichia pastoris, resulting in their purification with high yield (0.14 and 0.99 mg per gram cells for BoPIP1;2 and BoPIP2;2). We reconstituted AQPs in liposomes to study their functionality, and the size of proteoliposomes did not change concerning liposomes. BoPIP2;2 facilitated water transport, which was preserved for seven days at 4 °C and at room temperature but not at 37 °C. BoPIP2;2 was incorporated into liposomes to encapsulate a resveratrol extract, resulting in increased entrapment efficiency (EE) compared to conventional liposomes. Molecular docking was utilized to identify binding sites in PIP2s for resveratrol, highlighting the role of aquaporins in the improved EE. Moreover, interactions between plant AQP and human integrin were shown, which may increase internalization by the human target cells. Our results suggest AQP-based alternative encapsulation systems can be used in specifically targeted biotechnological applications.
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Affiliation(s)
- Lucia Yepes-Molina
- Aquaporins Group, Centro de Edafologia y Biologia Aplicada del Segura (CEBAS), CSIC, Campus de Espinardo, E-30100 Murcia, Spain;
| | - José A. Teruel
- Department of Biochemistry and Molecular Biology, Facultad de Veterinaria, Universidad de Murcia, E-30100 Murcia, Spain;
| | - Urban Johanson
- Division of Biochemistry and Structural Biology, Center for Molecular Protein Science, Department of Chemistry, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden
| | - Micaela Carvajal
- Aquaporins Group, Centro de Edafologia y Biologia Aplicada del Segura (CEBAS), CSIC, Campus de Espinardo, E-30100 Murcia, Spain;
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Bill RM, Hedfalk K. Aquaporins - Expression, purification and characterization. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2021; 1863:183650. [PMID: 34019902 DOI: 10.1016/j.bbamem.2021.183650] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 05/11/2021] [Accepted: 05/12/2021] [Indexed: 11/29/2022]
Abstract
Aquaporin water channels facilitate the bi-directional flow of water and small, neutral solutes down an osmotic gradient in all kingdoms of life. Over the last two decades, the availability of high-quality protein has underpinned progress in the structural and functional characterization of these water channels. In particular, recombinant protein technology has guaranteed the supply of aquaporin samples that were of sufficient quality and quantity for further study. Here we review the features of successful expression, purification and characterization strategies that have underpinned these successes and that will drive further breakthroughs in the field. Overall, Escherichia coli is a suitable host for prokaryotic isoforms, while Pichia pastoris is the most commonly-used recombinant host for eukaryotic variants. Generally, a two-step purification procedure is suitable after solubilization in glucopyranosides and most structures are determined by X-ray following crystallization.
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Affiliation(s)
- Roslyn M Bill
- College of Health and Life Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK
| | - Kristina Hedfalk
- Department of Chemistry and Molecular Biology, Gothenburg University, Box 462, 405 30 Göteborg, Sweden.
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Kell DB. A protet-based, protonic charge transfer model of energy coupling in oxidative and photosynthetic phosphorylation. Adv Microb Physiol 2021; 78:1-177. [PMID: 34147184 DOI: 10.1016/bs.ampbs.2021.01.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Textbooks of biochemistry will explain that the otherwise endergonic reactions of ATP synthesis can be driven by the exergonic reactions of respiratory electron transport, and that these two half-reactions are catalyzed by protein complexes embedded in the same, closed membrane. These views are correct. The textbooks also state that, according to the chemiosmotic coupling hypothesis, a (or the) kinetically and thermodynamically competent intermediate linking the two half-reactions is the electrochemical difference of protons that is in equilibrium with that between the two bulk phases that the coupling membrane serves to separate. This gradient consists of a membrane potential term Δψ and a pH gradient term ΔpH, and is known colloquially as the protonmotive force or pmf. Artificial imposition of a pmf can drive phosphorylation, but only if the pmf exceeds some 150-170mV; to achieve in vivo rates the imposed pmf must reach 200mV. The key question then is 'does the pmf generated by electron transport exceed 200mV, or even 170mV?' The possibly surprising answer, from a great many kinds of experiment and sources of evidence, including direct measurements with microelectrodes, indicates it that it does not. Observable pH changes driven by electron transport are real, and they control various processes; however, compensating ion movements restrict the Δψ component to low values. A protet-based model, that I outline here, can account for all the necessary observations, including all of those inconsistent with chemiosmotic coupling, and provides for a variety of testable hypotheses by which it might be refined.
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Affiliation(s)
- Douglas B Kell
- Department of Biochemistry and Systems Biology, Institute of Systems, Molecular and Integrative, Biology, University of Liverpool, Liverpool, United Kingdom; The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Lyngby, Denmark.
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Munro R, de Vlugt J, Ladizhansky V, Brown LS. Improved Protocol for the Production of the Low-Expression Eukaryotic Membrane Protein Human Aquaporin 2 in Pichia pastoris for Solid-State NMR. Biomolecules 2020; 10:biom10030434. [PMID: 32168846 PMCID: PMC7175339 DOI: 10.3390/biom10030434] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 03/05/2020] [Accepted: 03/06/2020] [Indexed: 12/16/2022] Open
Abstract
Solid-state nuclear magnetic resonance (SSNMR) is a powerful biophysical technique for studies of membrane proteins; it requires the incorporation of isotopic labels into the sample. This is usually accomplished through over-expression of the protein of interest in a prokaryotic or eukaryotic host in minimal media, wherein all (or some) carbon and nitrogen sources are isotopically labeled. In order to obtain multi-dimensional NMR spectra with adequate signal-to-noise ratios suitable for in-depth analysis, one requires high yields of homogeneously structured protein. Some membrane proteins, such as human aquaporin 2 (hAQP2), exhibit poor expression, which can make producing a sample for SSNMR in an economic fashion extremely difficult, as growth in minimal media adds additional strain on expression hosts. We have developed an optimized growth protocol for eukaryotic membrane proteins in the methylotrophic yeast Pichia pastoris. Our new growth protocol uses the combination of sorbitol supplementation, higher cell density, and low temperature induction (LT-SEVIN), which increases the yield of full-length, isotopically labeled hAQP2 ten-fold. Combining mass spectrometry and SSNMR, we were able to determine the nature and the extent of post-translational modifications of the protein. The resultant protein can be functionally reconstituted into lipids and yields excellent resolution and spectral coverage when analyzed by two-dimensional SSNMR spectroscopy.
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Characterization of aquaporin-driven hydrogen peroxide transport. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2019; 1862:183065. [PMID: 31521632 DOI: 10.1016/j.bbamem.2019.183065] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 08/20/2019] [Accepted: 09/10/2019] [Indexed: 12/31/2022]
Abstract
Aquaporins are membrane-intrinsic proteins initially defined as water (H2O) channels in all organisms and subsequently found to have multiple substrate specificities, such as hydrogen peroxide (H2O2). H2O2 is a signaling molecule that partakes in immune responses where its transport is mediated by aquaporins. To shed further light on the molecular basis of the aquaporin function in H2O2 transport, we have characterized an Arabidopsis thaliana aquaporin, AtPIP2;4, recombinantly produced to high yields in Pichia pastoris. Here, we present a newly established assay that allows detection of H2O2 transport by purified aquaporins reconstituted into liposomes, enabling us to compare aquaporin homologues with respect to substrate specificity. To get additional insight into the structural determinants for aquaporin-mediated H2O2 transport, we solved the 3D-structure of AtPIP2;4 to 3.7 Å resolution and found structural identity to the water channel from spinach (SoPIP2;1), with the difference that Cd2+ cation is not required to retain the closed conformation. The transport specificities of the two plant aquaporins were compared to a human homologue, AQP1. Overall, we conclude that AtPIP2;4, SoPIP2;1 and hAQP1 are all transporters of both H2O and H2O2, but have different efficiencies for various specificities. Notably, all three homologues expedite H2O transport equally well while the plant aquaporins are more permeable to H2O2 than hAQP1. Comparison of the structures indicates that the observed variations in H2O and H2O2 transport cannot be explained by differences in the monomeric pore. Possibly, the determinants for transport specificities reside in the flexible domains outside the membrane core of these channels.
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Purification and functional comparison of nine human Aquaporins produced in Saccharomyces cerevisiae for the purpose of biophysical characterization. Sci Rep 2017; 7:16899. [PMID: 29203835 PMCID: PMC5715081 DOI: 10.1038/s41598-017-17095-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Accepted: 11/20/2017] [Indexed: 12/31/2022] Open
Abstract
The sparse number of high-resolution human membrane protein structures severely restricts our comprehension of molecular physiology and ability to exploit rational drug design. In the search for a standardized, cheap and easily handled human membrane protein production platform, we thoroughly investigated the capacity of S. cerevisiae to deliver high yields of prime quality human AQPs, focusing on poorly characterized members including some previously shown to be difficult to isolate. Exploiting GFP labeled forms we comprehensively optimized production and purification procedures resulting in satisfactory yields of all nine AQP targets. We applied the obtained knowledge to successfully upscale purification of histidine tagged human AQP10 produced in large bioreactors. Glycosylation analysis revealed that AQP7 and 12 were O-glycosylated, AQP10 was N-glycosylated while the other AQPs were not glycosylated. We furthermore performed functional characterization and found that AQP 2, 6 and 8 allowed flux of water whereas AQP3, 7, 9, 10, 11 and 12 also facilitated a glycerol flux. In conclusion, our S. cerevisiae platform emerges as a powerful tool for isolation of functional, difficult-to-express human membrane proteins suitable for biophysical characterization.
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Wambo TO, Rodriguez RA, Chen LY. Computing osmotic permeabilities of aquaporins AQP4, AQP5, and GlpF from near-equilibrium simulations. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1859:1310-1316. [PMID: 28455098 DOI: 10.1016/j.bbamem.2017.04.022] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2017] [Revised: 04/23/2017] [Accepted: 04/24/2017] [Indexed: 12/01/2022]
Abstract
Measuring or computing the single-channel permeability of aquaporins/aquaglyceroporins (AQPs) has long been a challenge. The measured values scatter over an order of magnitude but the corresponding Arrhenius activation energies converge in the current literature. Osmotic flux through an AQP was simulated as water current forced through the channel by kilobar hydraulic pressure or theoretically approximated as single-file diffusion. In this paper, we report large scale simulations of osmotic current under sub M gradient through three AQPs (water channels AQP4 and AQP5 and glycerol-water channel GlpF) using the mature particle mesh Ewald technique (PME) for which the established force fields have been optimized with known accuracy. These simulations were implemented with hybrid periodic boundary conditions devised to avoid the artifactitious mixing across the membrane in a regular PME simulation. The computed single-channel permeabilities at 5°C and 25°C are in agreement with recently refined experiments on GlpF. The Arrhenius activation energies extracted from our simulations for all the three AQPs agree with the in vitro measurements. The single-file diffusion approximations from our large-scale simulations are consistent with the current literature on smaller systems. From these unambiguous agreements among the in vitro and in silico studies, we observe the quantitative accuracy of the all-atom force fields of the current literature for water-channel biology. We also observe that AQP4, that is particularly rich in the central nervous system, is more efficient in water conduction and more temperature-sensitive than other water-only channels (excluding glycerol channels that also conduct water when not inhibited by glycerol).
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Affiliation(s)
- Thierry O Wambo
- Department of Physics, University of Texas at San Antonio, San Antonio, TX 78249, USA
| | - Roberto A Rodriguez
- Department of Physics, University of Texas at San Antonio, San Antonio, TX 78249, USA
| | - Liao Y Chen
- Department of Physics, University of Texas at San Antonio, San Antonio, TX 78249, USA.
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Ampah-Korsah H, Sonntag Y, Engfors A, Kirscht A, Kjellbom P, Johanson U. Single amino acid substitutions in the selectivity filter render NbXIP1;1α aquaporin water permeable. BMC PLANT BIOLOGY 2017; 17:61. [PMID: 28279171 PMCID: PMC5345251 DOI: 10.1186/s12870-017-1009-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Accepted: 02/28/2017] [Indexed: 05/22/2023]
Abstract
BACKGROUND Aquaporins (AQPs) are integral membrane proteins that facilitate transport of water and/or other small neutral solutes across membranes in all forms of life. The X Intrinsic Proteins (XIPs) are the most recently recognized and the least characterized aquaporin subfamily in higher plants. XIP1s have been shown to be impermeable to water but permeable to boric acid, glycerol, hydrogen peroxide and urea. However, uncertainty regarding the determinants for selectivity and lack of an activity that is easy to quantify have hindered functional investigations. In an effort to resolve these issues, we set out to introduce water permeability in Nicotiana benthamiana XIP1;1α (NbXIP1;1α), by exchanging amino acid residues of predicted alternative aromatic/arginine (ar/R) selectivity filters of NbXIP1;1α for residues constituting the water permeable ar/R selectivity filter of AtTIP2;1. RESULTS Here, we present functional results regarding the amino acid substitutions in the putative filters as well as deletions in loops C and D of NbXIP1;1α. In addition, homology models were created based on the high resolution X-ray structure of AtTIP2;1 to rationalize the functional properties of wild-type and mutant NbXIP1;1α. Our results favour Thr 246 rather than Val 242 as the residue at the helix 5 position in the ar/R filter of NbXIP1;1α and indicate that the pore is not occluded by the loops when heterologously expressed in Pichia pastoris. Moreover, our results show that a single amino acid substitution in helix 1 (L79G) or in helix 2 (I102H) is sufficient to render NbXIP1;1α water permeable. Most of the functional results can be rationalized from the models based on a combination of aperture and hydrophobicity of the ar/R filter. CONCLUSION The water permeable NbXIP1;1α mutants imply that the heterologously expressed proteins are correctly folded and offer means to explore the structural and functional properties of NbXIP1;1α. Our results support that Thr 246 is part of the ar/R filter. Furthermore, we suggest that a salt bridge to an acidic residue in helix 1, conserved among the XIPs in clade B, directs the orientation of the arginine in the ar/R selectivity filter and provides a novel approach to tune the selectivity of AQPs.
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Affiliation(s)
- Henry Ampah-Korsah
- Center for Molecular Protein Science, Department of Biochemistry and Structural Biology, Lund University, Box 124, SE-221 00 Lund, Sweden
| | - Yonathan Sonntag
- Center for Molecular Protein Science, Department of Biochemistry and Structural Biology, Lund University, Box 124, SE-221 00 Lund, Sweden
| | - Angelica Engfors
- Center for Molecular Protein Science, Department of Biochemistry and Structural Biology, Lund University, Box 124, SE-221 00 Lund, Sweden
| | - Andreas Kirscht
- Center for Molecular Protein Science, Department of Biochemistry and Structural Biology, Lund University, Box 124, SE-221 00 Lund, Sweden
| | - Per Kjellbom
- Center for Molecular Protein Science, Department of Biochemistry and Structural Biology, Lund University, Box 124, SE-221 00 Lund, Sweden
| | - Urban Johanson
- Center for Molecular Protein Science, Department of Biochemistry and Structural Biology, Lund University, Box 124, SE-221 00 Lund, Sweden
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Yu L, Rodriguez RA, Chen LL, Chen LY, Perry G, McHardy SF, Yeh CK. 1,3-propanediol binds deep inside the channel to inhibit water permeation through aquaporins. Protein Sci 2016; 25:433-41. [PMID: 26481430 DOI: 10.1002/pro.2832] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2015] [Revised: 10/15/2015] [Accepted: 10/16/2015] [Indexed: 01/10/2023]
Abstract
Aquaporins and aquaglyceroporins (AQPs) are membrane channel proteins responsible for transport of water and for transport of glycerol in addition to water across the cell membrane, respectively. They are expressed throughout the human body and also in other forms of life. Inhibitors of human AQPs have been sought for therapeutic treatment for various medical conditions including hypertension, refractory edema, neurotoxic brain edema, and so forth. Conducting all-atom molecular dynamics simulations, we computed the binding affinity of acetazolamide to human AQP4 that agrees closely with in vitro experiments. Using this validated computational method, we found that 1,3-propanediol (PDO) binds deep inside the AQP4 channel to inhibit that particular aquaporin efficaciously. Furthermore, we used the same method to compute the affinities of PDO binding to four other AQPs and one aquaglyceroporin whose atomic coordinates are available from the protein data bank (PDB). For bovine AQP1, human AQP2, AQP4, AQP5, and Plasmodium falciparum PfAQP whose structures were resolved with high resolution, we obtained definitive predictions on the PDO dissociation constant. For human AQP1 whose PDB coordinates are less accurate, we estimated the dissociation constant with a rather large error bar. Taking into account the fact that PDO is generally recognized as safe by the US FDA, we predict that PDO can be an effective diuretic which directly modulates water flow through the protein channels. It should be free from the serious side effects associated with other diuretics that change the hydro-homeostasis indirectly by altering the osmotic gradients.
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Affiliation(s)
- Lili Yu
- Department of Physics, University of Texas at San Antonio, San Antonio, Texas, 78249
| | - Roberto A Rodriguez
- Department of Physics, University of Texas at San Antonio, San Antonio, Texas, 78249
| | - L Laurie Chen
- Medical School, University of Texas Southwestern Medical Center, Dallas, Texas, 75390
| | - Liao Y Chen
- Department of Physics, University of Texas at San Antonio, San Antonio, Texas, 78249
| | - George Perry
- Department of Biology, University of Texas at San Antonio, San Antonio, Texas, 78249
| | - Stanton F McHardy
- Department of Chemistry, University of Texas at San Antonio, San Antonio, Texas, 78249
| | - Chih-Ko Yeh
- Department of Comprehensive Dentistry, University of Texas Health Science Center at San Antonio & GRECC, South Texas Veterans Health Care System, San Antonio, Texas 78229
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Sjöhamn J, Båth P, Neutze R, Hedfalk K. Applying bimolecular fluorescence complementation to screen and purify aquaporin protein:protein complexes. Protein Sci 2016; 25:2196-2208. [PMID: 27643892 PMCID: PMC5119558 DOI: 10.1002/pro.3046] [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: 06/30/2016] [Revised: 09/14/2016] [Accepted: 09/14/2016] [Indexed: 12/22/2022]
Abstract
Protein:protein interactions play key functional roles in the molecular machinery of the cell. A major challenge for structural biology is to gain high‐resolution structural insight into how membrane protein function is regulated by protein:protein interactions. To this end we present a method to express, detect, and purify stable membrane protein complexes that are suitable for further structural characterization. Our approach utilizes bimolecular fluorescence complementation (BiFC), whereby each protein of an interaction pair is fused to nonfluorescent fragments of yellow fluorescent protein (YFP) that combine and mature as the complex is formed. YFP thus facilitates the visualization of protein:protein interactions in vivo, stabilizes the assembled complex, and provides a fluorescent marker during purification. This technique is validated by observing the formation of stable homotetramers of human aquaporin 0 (AQP0). The method's broader applicability is demonstrated by visualizing the interactions of AQP0 and human aquaporin 1 (AQP1) with the cytoplasmic regulatory protein calmodulin (CaM). The dependence of the AQP0‐CaM complex on the AQP0 C‐terminus is also demonstrated since the C‐terminal truncated construct provides a negative control. This screening approach may therefore facilitate the production and purification of membrane protein:protein complexes for later structural studies by X‐ray crystallography or single particle electron microscopy.
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Affiliation(s)
- Jennie Sjöhamn
- Department of Chemistry and Molecular Biology, University of Gothenburg, Göteborg, SE-405 30, Sweden
| | - Petra Båth
- Department of Chemistry and Molecular Biology, University of Gothenburg, Göteborg, SE-405 30, Sweden
| | - Richard Neutze
- Department of Chemistry and Molecular Biology, University of Gothenburg, Göteborg, SE-405 30, Sweden
| | - Kristina Hedfalk
- Department of Chemistry and Molecular Biology, University of Gothenburg, Göteborg, SE-405 30, Sweden
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Yu L, Villarreal OD, Chen LL, Chen LY. 1,3-Propanediol binds inside the water-conducting pore of aquaporin 4: Does this efficacious inhibitor have sufficient potency? ACTA ACUST UNITED AC 2016; 2:91-98. [PMID: 27213050 DOI: 10.15761/jsin.1000117] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Among the thirteen types of water channel proteins, aquaporins (AQPs), which play various essential roles in human physiology, AQP4 is richly expressed in cells of the central nervous system and implicated in pathological conditions such as brain edema. Therefore, researchers have been looking for ways to inhibit AQP4's water-conducting function. Many small molecules have been investigated for their interactions with the residues that form the AQP4 channel entry vestibule on the extracellular side and their interruption of waters entering into the conducting pore. Conducting all-atom simulations on the basis of CHARMM 36 force field, we study one such inhibitor, 5-acetamido-1,3,4-thiadiazole-2-sulfonamide (AZM), to achieve quantitative agreement between the computed and the experimentally measured values of AZM-AQP4 binding affinity. Using the same method, we examine the possibility of plugging up the AQP4 channel around the Asn-Pro-Ala motifs located near the channel center because a small molecule bound there would totally occlude water conduction through AQP4. We compute the binding affinities of 1,2-ethanediol (EDO) and 1,3-propanediol (PDO) inside the AQP4 conducting pore and identify the specificities of the interactions. The EDO-AQP4 interaction is weak with a dissociation constant of 80 mM. The PDO-AQP4 interaction is rather strong with a dissociation constant of 328 μM, which indicates that PDO is an efficacious AQP4 inhibitor with sufficiently high potency. Considering the fact that PDO is classified by the US Food and Drug Administration as generally safe, we predict that 1,3-propanediol could be an effective drug for brain edema and other AQP4-correlated neurological conditions.
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Affiliation(s)
- Lili Yu
- Department of Physics, University of Texas at San Antonio, San Antonio, Texas 78249, USA
| | - Oscar D Villarreal
- Department of Physics, University of Texas at San Antonio, San Antonio, Texas 78249, USA
| | - L Laurie Chen
- Medical School, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Liao Y Chen
- Department of Physics, University of Texas at San Antonio, San Antonio, Texas 78249, USA
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12
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Cell Surface and Membrane Engineering: Emerging Technologies and Applications. J Funct Biomater 2015; 6:454-85. [PMID: 26096148 PMCID: PMC4493524 DOI: 10.3390/jfb6020454] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Revised: 06/08/2015] [Accepted: 06/12/2015] [Indexed: 12/31/2022] Open
Abstract
Membranes constitute the interface between the basic unit of life—a single cell—and the outside environment and thus in many ways comprise the ultimate “functional biomaterial”. To perform the many and often conflicting functions required in this role, for example to partition intracellular contents from the outside environment while maintaining rapid intake of nutrients and efflux of waste products, biological membranes have evolved tremendous complexity and versatility. This article describes how membranes, mainly in the context of living cells, are increasingly being manipulated for practical purposes with drug discovery, biofuels, and biosensors providing specific, illustrative examples. Attention is also given to biology-inspired, but completely synthetic, membrane-based technologies that are being enabled by emerging methods such as bio-3D printers. The diverse set of applications covered in this article are intended to illustrate how these versatile technologies—as they rapidly mature—hold tremendous promise to benefit human health in numerous ways ranging from the development of new medicines to sensitive and cost-effective environmental monitoring for pathogens and pollutants to replacing hydrocarbon-based fossil fuels.
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Isotope Labeling of Eukaryotic Membrane Proteins in Yeast for Solid-State NMR. Methods Enzymol 2015; 565:193-212. [DOI: 10.1016/bs.mie.2015.05.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2023]
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Emmerstorfer A, Wriessnegger T, Hirz M, Pichler H. Overexpression of membrane proteins from higher eukaryotes in yeasts. Appl Microbiol Biotechnol 2014; 98:7671-98. [PMID: 25070595 DOI: 10.1007/s00253-014-5948-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Revised: 07/08/2014] [Accepted: 07/09/2014] [Indexed: 02/08/2023]
Abstract
Heterologous expression and characterisation of the membrane proteins of higher eukaryotes is of paramount interest in fundamental and applied research. Due to the rather simple and well-established methods for their genetic modification and cultivation, yeast cells are attractive host systems for recombinant protein production. This review provides an overview on the remarkable progress, and discusses pitfalls, in applying various yeast host strains for high-level expression of eukaryotic membrane proteins. In contrast to the cell lines of higher eukaryotes, yeasts permit efficient library screening methods. Modified yeasts are used as high-throughput screening tools for heterologous membrane protein functions or as benchmark for analysing drug-target relationships, e.g., by using yeasts as sensors. Furthermore, yeasts are powerful hosts for revealing interactions stabilising and/or activating membrane proteins. We also discuss the stress responses of yeasts upon heterologous expression of membrane proteins. Through co-expression of chaperones and/or optimising yeast cultivation and expression strategies, yield-optimised hosts have been created for membrane protein crystallography or efficient whole-cell production of fine chemicals.
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Affiliation(s)
- Anita Emmerstorfer
- ACIB-Austrian Centre of Industrial Biotechnology, Petersgasse 14, 8010, Graz, Austria
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15
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Pirazzi C, Valenti L, Motta BM, Pingitore P, Hedfalk K, Mancina RM, Burza MA, Indiveri C, Ferro Y, Montalcini T, Maglio C, Dongiovanni P, Fargion S, Rametta R, Pujia A, Andersson L, Ghosal S, Levin M, Wiklund O, Iacovino M, Borén J, Romeo S. PNPLA3 has retinyl-palmitate lipase activity in human hepatic stellate cells. Hum Mol Genet 2014; 23:4077-85. [PMID: 24670599 PMCID: PMC4082369 DOI: 10.1093/hmg/ddu121] [Citation(s) in RCA: 258] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Retinoids are micronutrients that are stored as retinyl esters in the retina and hepatic stellate cells (HSCs). HSCs are key players in fibrogenesis in chronic liver diseases. The enzyme responsible for hydrolysis and release of retinyl esters from HSCs is unknown and the relationship between retinoid metabolism and liver disease remains unclear. We hypothesize that the patatin-like phospholipase domain-containing 3 (PNPLA3) protein is involved in retinol metabolism in HSCs. We tested our hypothesis both in primary human HSCs and in a human cohort of subjects with non-alcoholic fatty liver disease (N = 146). Here we show that PNPLA3 is highly expressed in human HSCs. Its expression is regulated by retinol availability and insulin, and increased PNPLA3 expression results in reduced lipid droplet content. PNPLA3 promotes extracellular release of retinol from HSCs in response to insulin. We also show that purified wild-type PNPLA3 hydrolyzes retinyl palmitate into retinol and palmitic acid. Conversely, this enzymatic activity is markedly reduced with purified PNPLA3 148M, a common mutation robustly associated with liver fibrosis and hepatocellular carcinoma development. We also find the PNPLA3 I148M genotype to be an independent (P = 0.009 in a multivariate analysis) determinant of circulating retinol-binding protein 4, a reliable proxy for retinol levels in humans. This study identifies PNPLA3 as a lipase responsible for retinyl-palmitate hydrolysis in HSCs in humans. Importantly, this indicates a potential novel link between HSCs, retinoid metabolism and PNPLA3 in determining the susceptibility to chronic liver disease.
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Affiliation(s)
- Carlo Pirazzi
- Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Center for Cardiovascular and Metabolic Research, Wallenberg Laboratory and
| | - Luca Valenti
- Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | - Benedetta Maria Motta
- Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Center for Cardiovascular and Metabolic Research, Wallenberg Laboratory and Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | - Piero Pingitore
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden Department BEST (Biologia, Ecologia, Scienze Della Terra), Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Arcavacata di Rende, Italy
| | - Kristina Hedfalk
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
| | - Rosellina Margherita Mancina
- Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Center for Cardiovascular and Metabolic Research, Wallenberg Laboratory and Department of Medical and Surgical Sciences, Clinical Nutrition Unit, University Magna Graecia of Catanzaro, Catanzaro, Italy
| | - Maria Antonella Burza
- Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Center for Cardiovascular and Metabolic Research, Wallenberg Laboratory and
| | - Cesare Indiveri
- Department BEST (Biologia, Ecologia, Scienze Della Terra), Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Arcavacata di Rende, Italy
| | - Yvelise Ferro
- Department of Medical and Surgical Sciences, Clinical Nutrition Unit, University Magna Graecia of Catanzaro, Catanzaro, Italy
| | - Tiziana Montalcini
- Department of Medical and Surgical Sciences, Clinical Nutrition Unit, University Magna Graecia of Catanzaro, Catanzaro, Italy
| | - Cristina Maglio
- Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Center for Cardiovascular and Metabolic Research, Wallenberg Laboratory and
| | - Paola Dongiovanni
- Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | - Silvia Fargion
- Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | - Raffaela Rametta
- Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | - Arturo Pujia
- Department of Medical and Surgical Sciences, Clinical Nutrition Unit, University Magna Graecia of Catanzaro, Catanzaro, Italy
| | - Linda Andersson
- Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Center for Cardiovascular and Metabolic Research, Wallenberg Laboratory and
| | - Saswati Ghosal
- Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Center for Cardiovascular and Metabolic Research, Wallenberg Laboratory and
| | - Malin Levin
- Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Center for Cardiovascular and Metabolic Research, Wallenberg Laboratory and
| | - Olov Wiklund
- Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Center for Cardiovascular and Metabolic Research, Wallenberg Laboratory and
| | - Michelina Iacovino
- Department of Pediatrics, LA Biomedical Research Institute at Harbor-UCLA, 1124 W. Carson Street, HH1, Torrance, CA 90502, USA
| | - Jan Borén
- Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Center for Cardiovascular and Metabolic Research, Wallenberg Laboratory and
| | - Stefano Romeo
- Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Center for Cardiovascular and Metabolic Research, Wallenberg Laboratory and Department of Medical and Surgical Sciences, Clinical Nutrition Unit, University Magna Graecia of Catanzaro, Catanzaro, Italy
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16
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Vogl T, Thallinger GG, Zellnig G, Drew D, Cregg JM, Glieder A, Freigassner M. Towards improved membrane protein production in Pichia pastoris: general and specific transcriptional response to membrane protein overexpression. N Biotechnol 2014; 31:538-52. [PMID: 24594271 DOI: 10.1016/j.nbt.2014.02.009] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Revised: 02/20/2014] [Accepted: 02/23/2014] [Indexed: 01/13/2023]
Abstract
Membrane proteins are the largest group of human drug targets and are also used as biocatalysts. However, due to their complexity, efficient expression remains a bottleneck for high level production. In recent years, the methylotrophic yeast Pichia pastoris has emerged as one of the most commonly used expression systems for membrane protein production. Here, we have analysed the transcriptomes of P. pastoris strains producing different classes of membrane proteins (mitochondrial, ER/Golgi and plasma membrane localized) to understand the cellular response and to identify targets to engineer P. pastoris towards an improved chassis for membrane protein production. Microarray experiments revealed varying transcriptional responses depending on the enzymatic activity, subcellular localization and physiological role of the membrane proteins. While an alternative oxidase evoked primarily a response within the mitochondria, the overexpression of transporters entering the secretory pathway had a wide effect on lipid metabolism and induced the upregulation of the UPR (unfolded protein response) transcription factor Hac1p. Coexpression of P. pastoris endogenous HAC1 increased the levels of ER-resident membrane proteins 1.5- to 2.1-fold. Subsequent transcriptome analysis of HAC1 coexpression revealed an upregulation of the folding machinery correlating with an expansion of the ER membrane capacity, thus boosting membrane protein production. Hence, our study has helped to elucidate the cellular response of P. pastoris to the expression of different classes of membrane proteins and led specifically to new insights into the effect of PpHac1p on membrane proteins entering the secretory pathway.
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Affiliation(s)
- Thomas Vogl
- Institute for Molecular Biotechnology, Graz University of Technology, Petersgasse 14/2, 8010 Graz, Austria
| | - Gerhard G Thallinger
- Institute for Genomics and Bioinformatics, Graz University of Technology, Petersgasse 14/5, 8010 Graz, Austria; Omics Center Graz, Stiftingtalstrasse 24, 8036 Graz, Austria; Austrian Centre of Industrial Biotechnology (ACIB GmbH), Petersgasse 14/5, 8010 Graz, Austria
| | - Guenther Zellnig
- Institute of Plant Sciences, University of Graz, Schubertstrasse 51, 8010 Graz, Austria
| | - David Drew
- Division of Molecular Biosciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - James M Cregg
- Keck Graduate Institute of Applied Life Sciences, 535 Watson Drive, Claremont, CA 91711, USA
| | - Anton Glieder
- Austrian Centre of Industrial Biotechnology (ACIB GmbH), Petersgasse 14/5, 8010 Graz, Austria
| | - Maria Freigassner
- Institute for Molecular Biotechnology, Graz University of Technology, Petersgasse 14/2, 8010 Graz, Austria.
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17
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Pingitore P, Pirazzi C, Mancina RM, Motta BM, Indiveri C, Pujia A, Montalcini T, Hedfalk K, Romeo S. Recombinant PNPLA3 protein shows triglyceride hydrolase activity and its I148M mutation results in loss of function. Biochim Biophys Acta Mol Cell Biol Lipids 2013; 1841:574-80. [PMID: 24369119 DOI: 10.1016/j.bbalip.2013.12.006] [Citation(s) in RCA: 130] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Revised: 12/07/2013] [Accepted: 12/14/2013] [Indexed: 12/13/2022]
Abstract
The patatin-like phospholipase domain containing 3 (PNPLA3, also called adiponutrin, ADPN) is a membrane-bound protein highly expressed in the liver. The genetic variant I148M (rs738409) was found to be associated with progression of chronic liver disease. We aimed to establish a protein purification protocol in a yeast system (Pichia pastoris) and to examine the human PNPLA3 enzymatic activity, substrate specificity and the I148M mutation effect. hPNPLA3 148I wild type and 148M mutant cDNA were cloned into P. pastoris expression vectors. Yeast cells were grown in 3L fermentors. PNPLA3 protein was purified from membrane fractions by Ni-affinity chromatography. Enzymatic activity was assessed using radiolabeled substrates. Both 148I wild type and 148M mutant proteins are localized to the membrane. The wild type protein shows a predominant lipase activity with mild lysophosphatidic acid acyl transferase activity (LPAAT) and the I148M mutation results in a loss of function of both these activities. Our data show that PNPLA3 has a predominant lipase activity and I148M mutation results in a loss of function.
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Affiliation(s)
- Piero Pingitore
- Department BEST (Biologia, Ecologia, Scienze della Terra), Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Via P. Bucci 4c, 87036 Arcavacata di Rende, Italy; Department of Chemistry and Molecular Biology, University of Gothenburg, PO Box 462, SE-405 30 Göteborg, Sweden
| | - Carlo Pirazzi
- Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Center for Cardiovascular and Metabolic Research, Wallenberg Laboratory, University of Gothenburg, Bruna Stråket, 16 SE-413 45 Göteborg, Sweden
| | - Rosellina M Mancina
- Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Center for Cardiovascular and Metabolic Research, Wallenberg Laboratory, University of Gothenburg, Bruna Stråket, 16 SE-413 45 Göteborg, Sweden; Department of Medical and Surgical Sciences, Clinical Nutrition Unit, University Magna Graecia of Catanzaro, Viale Europa, Localitá Germaneto, 88100 Catanzaro, Italy
| | - Benedetta M Motta
- Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Center for Cardiovascular and Metabolic Research, Wallenberg Laboratory, University of Gothenburg, Bruna Stråket, 16 SE-413 45 Göteborg, Sweden; Department of Pathophysiology and Transplantation, University of Milan, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122 Milan, Italy
| | - Cesare Indiveri
- Department BEST (Biologia, Ecologia, Scienze della Terra), Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Via P. Bucci 4c, 87036 Arcavacata di Rende, Italy
| | - Arturo Pujia
- Department of Medical and Surgical Sciences, Clinical Nutrition Unit, University Magna Graecia of Catanzaro, Viale Europa, Localitá Germaneto, 88100 Catanzaro, Italy
| | - Tiziana Montalcini
- Department of Medical and Surgical Sciences, Clinical Nutrition Unit, University Magna Graecia of Catanzaro, Viale Europa, Localitá Germaneto, 88100 Catanzaro, Italy
| | - Kristina Hedfalk
- Department of Chemistry and Molecular Biology, University of Gothenburg, PO Box 462, SE-405 30 Göteborg, Sweden.
| | - Stefano Romeo
- Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Center for Cardiovascular and Metabolic Research, Wallenberg Laboratory, University of Gothenburg, Bruna Stråket, 16 SE-413 45 Göteborg, Sweden; Department of Medical and Surgical Sciences, Clinical Nutrition Unit, University Magna Graecia of Catanzaro, Viale Europa, Localitá Germaneto, 88100 Catanzaro, Italy.
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18
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Unraveling aquaporin interaction partners. Biochim Biophys Acta Gen Subj 2013; 1840:1614-23. [PMID: 24252279 DOI: 10.1016/j.bbagen.2013.11.012] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Revised: 11/07/2013] [Accepted: 11/12/2013] [Indexed: 12/18/2022]
Abstract
BACKGROUND Insight into protein-protein interactions (PPIs) is highly desirable in order to understand the physiology of cellular events. This understanding is one of the challenges in biochemistry and molecular biology today, especially for eukaryotic membrane proteins where hurdles of production, purification and structural determination must be passed. SCOPE OF REVIEW We have explored the common strategies used to find medically relevant interaction partners of aquaporins (AQPs). The most frequently used methods to detect direct contact, yeast two-hybrid interaction assay and co-precipitation, are described together with interactions specifically found for the selected targets AQP0, AQP2, AQP4 and AQP5. MAJOR CONCLUSIONS The vast majority of interactions involve the aquaporin C-terminus and the characteristics of the interaction partners are strikingly diverse. While the well-established methods for PPIs are robust, a novel approach like bimolecular fluorescence complementation (BiFC) is attractive for screening many conditions as well as transient interactions. The ultimate goal is structural evaluation of protein complexes in order to get mechanistic insight into how proteins communicate at a molecular level. GENERAL SIGNIFICANCE What we learn from the human aquaporin field in terms of method development and communication between proteins can be of major use for any integral membrane protein of eukaryotic origin. This article is part of a Special Issue entitled Aquaporins.
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Ahmadpour D, Geijer C, Tamás MJ, Lindkvist-Petersson K, Hohmann S. Yeast reveals unexpected roles and regulatory features of aquaporins and aquaglyceroporins. Biochim Biophys Acta Gen Subj 2013; 1840:1482-91. [PMID: 24076236 DOI: 10.1016/j.bbagen.2013.09.027] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Revised: 09/18/2013] [Accepted: 09/19/2013] [Indexed: 02/05/2023]
Abstract
BACKGROUND The yeast Saccharomyces cerevisiae provides unique opportunities to study roles and regulation of aqua/glyceroporins using frontline tools of genetics and genomics as well as molecular cell and systems biology. SCOPE OF REVIEW S. cerevisiae has two similar orthodox aquaporins. Based on phenotypes mediated by gene deletion or overexpression as well as on their expression pattern, the yeast aquaporins play important roles in key aspects of yeast biology: establishment of freeze tolerance, during spore formation as well as determination of cell surface properties for substrate adhesion and colony formation. Exactly how the aquaporins perform those roles and the mechanisms that regulate their function under such conditions remain to be elucidated. S. cerevisiae also has two different aquaglyceroporins. While the role of one of them, Yfl054c, remains to be determined, Fps1 plays critical roles in osmoregulation by controlling the accumulation of the osmolyte glycerol. Fps1 communicates with two osmo-sensing MAPK signalling pathways to perform its functions but the details of Fps1 regulation remain to be determined. MAJOR CONCLUSIONS Several phenotypes associated with aqua/glyceroporin function in yeasts have been established. However, how water and glycerol transport contribute to the observed effects is not understood in detail. Also many of the basic principles of regulation of yeast aqua/glyceroporins remain to be elucidated. GENERAL SIGNIFICANCE Studying the yeast aquaporins and aquaglyceroporins offers rich insight into the life style, evolution and adaptive responses of yeast and rewards us with discoveries of unexpected roles and regulatory mechanisms of members of this ancient protein family. This article is part of a Special Issue entitled Aquaporins.
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Affiliation(s)
- Doryaneh Ahmadpour
- Department of Chemistry and Molecular Biology, University of Gothenburg, Sweden
| | - Cecilia Geijer
- Department of Chemistry and Molecular Biology, University of Gothenburg, Sweden
| | - Markus J Tamás
- Department of Chemistry and Molecular Biology, University of Gothenburg, Sweden
| | | | - Stefan Hohmann
- Department of Chemistry and Molecular Biology, University of Gothenburg, Sweden.
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20
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Abstract
Membrane proteins have essential cellular functions and are therefore of high interest in both academia and industry. Many efforts have been made on producing those targets in yields allowing crystallization experiments aiming for high resolution structures and mechanistic understanding. The first step of production provides a crucial barrier to overcome, but what we now see, is great progress in membrane protein structural determination in a relatively short time. Achievements on recombinant protein production have been essential for this development and the yeast Pichia pastoris is the most commonly used host for eukaryotic membrane proteins. High-resolution structures nicely illustrate the successes in protein production, and this is the measure used by Ramón and Marin in their review "Advances in the production of membrane proteins in Pichia pastoris" from 2011. Here, additional advances on production and crystallization of eukaryotic membrane proteins are described and reflected on.
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Affiliation(s)
- Kristina Hedfalk
- Department of Chemistry and Molecular Biology; University of Gothenburg; Göteborg, Sweden
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