1
|
Herrera SA, Günther Pomorski T. Reconstitution of ATP-dependent lipid transporters: gaining insight into molecular characteristics, regulation, and mechanisms. Biosci Rep 2023; 43:BSR20221268. [PMID: 37417269 PMCID: PMC10412526 DOI: 10.1042/bsr20221268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 06/30/2023] [Accepted: 07/06/2023] [Indexed: 07/08/2023] Open
Abstract
Lipid transporters play a crucial role in supporting essential cellular processes such as organelle assembly, vesicular trafficking, and lipid homeostasis by driving lipid transport across membranes. Cryo-electron microscopy has recently resolved the structures of several ATP-dependent lipid transporters, but functional characterization remains a major challenge. Although studies of detergent-purified proteins have advanced our understanding of these transporters, in vitro evidence for lipid transport is still limited to a few ATP-dependent lipid transporters. Reconstitution into model membranes, such as liposomes, is a suitable approach to study lipid transporters in vitro and to investigate their key molecular features. In this review, we discuss the current approaches for reconstituting ATP-driven lipid transporters into large liposomes and common techniques used to study lipid transport in proteoliposomes. We also highlight the existing knowledge on the regulatory mechanisms that modulate the activity of lipid transporters, and finally, we address the limitations of the current approaches and future perspectives in this field.
Collapse
Affiliation(s)
- Sara Abad Herrera
- Department of Molecular Biochemistry, Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Bochum, Germany
| | - Thomas Günther Pomorski
- Department of Molecular Biochemistry, Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Bochum, Germany
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
| |
Collapse
|
2
|
Veit S, Paweletz LC, Günther Pomorski T. Determination of membrane protein orientation upon liposomal reconstitution down to the single vesicle level. Biol Chem 2023; 404:647-661. [PMID: 36857289 DOI: 10.1515/hsz-2022-0325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 02/07/2023] [Indexed: 03/02/2023]
Abstract
Reconstitution of membrane proteins into liposomal membranes represents a key technique in enabling functional analysis under well-defined conditions. In this review, we provide a brief introduction to selected methods that have been developed to determine membrane protein orientation after reconstitution in liposomes, including approaches based on proteolytic digestion with proteases, site-specific labeling, fluorescence quenching and activity assays. In addition, we briefly highlight new strategies based on single vesicle analysis to address the problem of sample heterogeneity.
Collapse
Affiliation(s)
- Sarina Veit
- Department of Molecular Biochemistry , Faculty of Chemistry and Biochemistry , NC 7/174, Ruhr University Bochum, Universitätsstraße 150, D-44780 Bochum, Germany
| | - Laura Charlotte Paweletz
- Department of Molecular Biochemistry , Faculty of Chemistry and Biochemistry , NC 7/174, Ruhr University Bochum, Universitätsstraße 150, D-44780 Bochum, Germany
| | - Thomas Günther Pomorski
- Department of Molecular Biochemistry , Faculty of Chemistry and Biochemistry , NC 7/174, Ruhr University Bochum, Universitätsstraße 150, D-44780 Bochum, Germany
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871, Frederiksberg C, Denmark
| |
Collapse
|
3
|
Kalyana Sundaram RV, Bera M, Coleman J, Weerakkody JS, Krishnakumar SS, Ramakrishnan S. Native Planar Asymmetric Suspended Membrane for Single-Molecule Investigations: Plasma Membrane on a Chip. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2205567. [PMID: 36328714 DOI: 10.1002/smll.202205567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Indexed: 06/16/2023]
Abstract
Cellular plasma membranes, in their role as gatekeepers to the external environment, host numerous protein assemblies and lipid domains that manage the movement of molecules into and out of cells, regulate electric potential, and direct cell signaling. The ability to investigate these roles on the bilayer at a single-molecule level in a controlled, in vitro environment while preserving lipid and protein architectures will provide deeper insights into how the plasma membrane works. A tunable silicon microarray platform that supports stable, planar, and asymmetric suspended lipid membranes (SLIM) using synthetic and native plasma membrane vesicles for single-molecule fluorescence investigations is developed. Essentially, a "plasma membrane-on-a-chip" system that preserves lipid asymmetry and protein orientation is created. By harnessing the combined potential of this platform with total internal reflection fluorescence (TIRF) microscopy, the authors are able to visualize protein complexes with single-molecule precision. This technology has widespread applications in biological processes that happen at the cellular membranes and will further the knowledge of lipid and protein assemblies.
Collapse
Affiliation(s)
- Ramalingam Venkat Kalyana Sundaram
- Nanobiology Institute, Yale University School of Medicine, West Haven, CT, 06516, USA
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, 06520, USA
| | - Manindra Bera
- Nanobiology Institute, Yale University School of Medicine, West Haven, CT, 06516, USA
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, 06520, USA
| | - Jeff Coleman
- Nanobiology Institute, Yale University School of Medicine, West Haven, CT, 06516, USA
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, 06520, USA
| | - Jonathan S Weerakkody
- Nanobiology Institute, Yale University School of Medicine, West Haven, CT, 06516, USA
- Department of Pathology, Yale University School of Medicine, New Haven, CT, 06520, USA
| | - Shyam S Krishnakumar
- Nanobiology Institute, Yale University School of Medicine, West Haven, CT, 06516, USA
- Department of Neurology, Yale University School of Medicine, New Haven, CT, 06520, USA
| | - Sathish Ramakrishnan
- Nanobiology Institute, Yale University School of Medicine, West Haven, CT, 06516, USA
- Department of Pathology, Yale University School of Medicine, New Haven, CT, 06520, USA
| |
Collapse
|
4
|
Paweletz LC, Veit S, Pomorski TG. A Fluorescence-based Approach Utilizing Self-labeling Enzyme Tags to Determine Protein Orientation in Large Unilamellar Vesicles. Bio Protoc 2022; 12:e4542. [PMID: 36505029 PMCID: PMC9711944 DOI: 10.21769/bioprotoc.4542] [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: 06/29/2022] [Revised: 09/12/2022] [Accepted: 09/16/2022] [Indexed: 11/06/2022] Open
Abstract
Reconstitution of membrane proteins into large unilamellar vesicles is an essential approach for their functional analysis under chemically defined conditions. The orientation of the protein in the liposomal membrane after reconstitution depends on many parameters, and its assessment is important prior to functional measurements. Common approaches for determining the orientation of a membrane-inserted protein are based on limited proteolytic digest, impermeable labeling reagents for specific amino acids, or membrane-impermeable quenchers for fluorescent proteins. Here, we describe a simple site-specific fluorescent assay based on self-labeling enzyme tags to determine the orientation of membrane proteins after reconstitution, exemplified on a reconstituted SNAP-tag plant H + -ATPase. This versatile method should benefit the optimization of reconstitution conditions and the analysis of many types of membrane proteins. Graphical abstract.
Collapse
Affiliation(s)
- Laura Charlotte Paweletz
- Department of Molecular Biochemistry, Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Bochum, Germany
| | - Sarina Veit
- Department of Molecular Biochemistry, Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Bochum, Germany
| | - Thomas Günther Pomorski
- Department of Molecular Biochemistry, Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Bochum, Germany
,
Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
,
*For correspondence:
| |
Collapse
|
5
|
Veit S, Paweletz LC, Bohr SSR, Menon AK, Hatzakis NS, Pomorski TG. Single Vesicle Fluorescence-Bleaching Assay for Multi-Parameter Analysis of Proteoliposomes by Total Internal Reflection Fluorescence Microscopy. ACS APPLIED MATERIALS & INTERFACES 2022; 14:29659-29667. [PMID: 35748880 PMCID: PMC11194769 DOI: 10.1021/acsami.2c07454] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Reconstitution of membrane proteins into model membranes is an essential approach for their functional analysis under chemically defined conditions. Established model-membrane systems used in ensemble average measurements are limited by sample heterogeneity and insufficient knowledge of lipid and protein content at the single vesicle level, which limits quantitative analysis of vesicle properties and prevents their correlation with protein activity. Here, we describe a versatile total internal reflection fluorescence microscopy-based bleaching protocol that permits parallel analysis of multiple parameters (physical size, tightness, unilamellarity, membrane protein content, and orientation) of individual proteoliposomes prepared with fluorescently tagged membrane proteins and lipid markers. The approach makes use of commercially available fluorophores including the commonly used nitrobenzoxadiazole dye and may be applied to deduce functional molecular characteristics of many types of reconstituted fluorescently tagged membrane proteins.
Collapse
Affiliation(s)
- Sarina Veit
- Department
of Molecular Biochemistry, Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Bochum 44801, Germany
| | - Laura Charlotte Paweletz
- Department
of Molecular Biochemistry, Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Bochum 44801, Germany
| | - Søren S.-R. Bohr
- Department
of Chemistry & Nano-Science Center, University of Copenhagen, Copenhagen DK-2100, Denmark
| | - Anant K. Menon
- Department
of Biochemistry, Weill Cornell Medical College, New York, New York 10065, United States
| | - Nikos S. Hatzakis
- Department
of Chemistry & Nano-Science Center, University of Copenhagen, Copenhagen DK-2100, Denmark
- NovoNordisk
Foundation Center for Protein Research,Copenhagen DK-2200, Denmark
| | - Thomas Günther Pomorski
- Department
of Molecular Biochemistry, Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Bochum 44801, Germany
- Department
of Plant and Environmental Sciences, University
of Copenhagen,Frederiksberg C DK-1871, Denmark
| |
Collapse
|
6
|
Stanchev LD, Rizzo J, Peschel R, Pazurek LA, Bredegaard L, Veit S, Laerbusch S, Rodrigues ML, López-Marqués RL, Günther Pomorski T. P-Type ATPase Apt1 of the Fungal Pathogen Cryptococcus neoformans Is a Lipid Flippase of Broad Substrate Specificity. J Fungi (Basel) 2021; 7:jof7100843. [PMID: 34682264 PMCID: PMC8537059 DOI: 10.3390/jof7100843] [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: 07/30/2021] [Revised: 09/29/2021] [Accepted: 10/01/2021] [Indexed: 11/16/2022] Open
Abstract
Lipid flippases of the P4-ATPase family are ATP-driven transporters that translocate lipids from the exoplasmic to the cytosolic leaflet of biological membranes. In the encapsulated fungal pathogen Cryptococcus neoformans, the P4-ATPase Apt1p is an important regulator of polysaccharide secretion and pathogenesis, but its biochemical characterization is lacking. Phylogenetic analysis revealed that Apt1p belongs to the subclade of P4A-ATPases characterized by the common requirement for a β-subunit. Using heterologous expression in S. cerevisiae, we demonstrate that Apt1p forms a heterodimeric complex with the C. neoformans Cdc50 protein. This association is required for both localization and activity of the transporter complex. Lipid flippase activity of the heterodimeric complex was assessed by complementation tests and uptake assays employing fluorescent lipids and revealed a broad substrate specificity, including several phospholipids, the alkylphospholipid miltefosine, and the glycolipids glucosyl- and galactosylceramide. Our results suggest that transbilayer lipid transport in C. neoformans is finely regulated to promote fungal virulence, which reinforces the potential of Apt1p as a target for antifungal drug development.
Collapse
Affiliation(s)
- Lyubomir Dimitrov Stanchev
- Department of Molecular Biochemistry, Faculty of Chemistry and Biochemistry, Ruhr University Bochum, 44780 Bochum, Germany; (L.D.S.); (R.P.); (L.A.P.); (S.V.); (S.L.)
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg, Denmark; (L.B.); (R.L.L.-M.)
| | - Juliana Rizzo
- Instituto de Microbiologia Paulo de Góes (IMPG), Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro 21941-902, Brazil; (J.R.); (M.L.R.)
- Unité Biologie des ARN des Pathogènes Fongiques, Département de Mycologie, Institut Pasteur, 75015 Paris, France
| | - Rebecca Peschel
- Department of Molecular Biochemistry, Faculty of Chemistry and Biochemistry, Ruhr University Bochum, 44780 Bochum, Germany; (L.D.S.); (R.P.); (L.A.P.); (S.V.); (S.L.)
| | - Lilli A. Pazurek
- Department of Molecular Biochemistry, Faculty of Chemistry and Biochemistry, Ruhr University Bochum, 44780 Bochum, Germany; (L.D.S.); (R.P.); (L.A.P.); (S.V.); (S.L.)
| | - Lasse Bredegaard
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg, Denmark; (L.B.); (R.L.L.-M.)
| | - Sarina Veit
- Department of Molecular Biochemistry, Faculty of Chemistry and Biochemistry, Ruhr University Bochum, 44780 Bochum, Germany; (L.D.S.); (R.P.); (L.A.P.); (S.V.); (S.L.)
| | - Sabine Laerbusch
- Department of Molecular Biochemistry, Faculty of Chemistry and Biochemistry, Ruhr University Bochum, 44780 Bochum, Germany; (L.D.S.); (R.P.); (L.A.P.); (S.V.); (S.L.)
| | - Marcio L. Rodrigues
- Instituto de Microbiologia Paulo de Góes (IMPG), Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro 21941-902, Brazil; (J.R.); (M.L.R.)
- Instituto Carlos Chagas, Fiocruz, Curitiba 81310-020, Brazil
| | - Rosa L. López-Marqués
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg, Denmark; (L.B.); (R.L.L.-M.)
| | - Thomas Günther Pomorski
- Department of Molecular Biochemistry, Faculty of Chemistry and Biochemistry, Ruhr University Bochum, 44780 Bochum, Germany; (L.D.S.); (R.P.); (L.A.P.); (S.V.); (S.L.)
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg, Denmark; (L.B.); (R.L.L.-M.)
- Correspondence: ; Tel.: +49-234-32-24430
| |
Collapse
|
7
|
Dekker WJC, Ortiz-Merino RA, Kaljouw A, Battjes J, Wiering FW, Mooiman C, Torre PDL, Pronk JT. Engineering the thermotolerant industrial yeast Kluyveromyces marxianus for anaerobic growth. Metab Eng 2021; 67:347-364. [PMID: 34303845 DOI: 10.1016/j.ymben.2021.07.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 07/06/2021] [Accepted: 07/13/2021] [Indexed: 10/20/2022]
Abstract
Current large-scale, anaerobic industrial processes for ethanol production from renewable carbohydrates predominantly rely on the mesophilic yeast Saccharomyces cerevisiae. Use of thermotolerant, facultatively fermentative yeasts such as Kluyveromyces marxianus could confer significant economic benefits. However, in contrast to S. cerevisiae, these yeasts cannot grow in the absence of oxygen. Responses of K. marxianus and S. cerevisiae to different oxygen-limitation regimes were analyzed in chemostats. Genome and transcriptome analysis, physiological responses to sterol supplementation and sterol-uptake measurements identified absence of a functional sterol-uptake mechanism as a key factor underlying the oxygen requirement of K. marxianus. Heterologous expression of a squalene-tetrahymanol cyclase enabled oxygen-independent synthesis of the sterol surrogate tetrahymanol in K. marxianus. After a brief adaptation under oxygen-limited conditions, tetrahymanol-expressing K. marxianus strains grew anaerobically on glucose at temperatures of up to 45 °C. These results open up new directions in the development of thermotolerant yeast strains for anaerobic industrial applications.
Collapse
Affiliation(s)
- Wijbrand J C Dekker
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629, HZ Delft, the Netherlands
| | - Raúl A Ortiz-Merino
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629, HZ Delft, the Netherlands
| | - Astrid Kaljouw
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629, HZ Delft, the Netherlands
| | - Julius Battjes
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629, HZ Delft, the Netherlands
| | - Frank W Wiering
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629, HZ Delft, the Netherlands
| | - Christiaan Mooiman
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629, HZ Delft, the Netherlands
| | - Pilar de la Torre
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629, HZ Delft, the Netherlands
| | - Jack T Pronk
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629, HZ Delft, the Netherlands.
| |
Collapse
|
8
|
Stanchev LD, Marek M, Xian F, Klöhn M, Silvestro D, Dittmar G, López-Marqués RL, Günther Pomorski T. Functional Significance of Conserved Cysteines in the Extracellular Loops of the ATP Binding Cassette Transporter Pdr11p. J Fungi (Basel) 2020; 7:jof7010002. [PMID: 33375075 PMCID: PMC7822014 DOI: 10.3390/jof7010002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 12/18/2020] [Indexed: 12/16/2022] Open
Abstract
The pleiotropic drug resistance (PDR) transporter Pdr11p is expressed under anaerobic growth conditions at the plasma membrane of the yeast Saccharomyces cerevisiae, where it facilitates the uptake of exogenous sterols. Members of the fungal PDR family contain six conserved cysteines in their extracellular loops (ECL). For the functional analysis of these cysteine residues in Pdr11p, we generated a series of single cysteine-to-serine mutants. All mutant proteins expressed well and displayed robust ATPase activity upon purification. Mass-spectrometry analysis identified two cysteine residues (C582 and C603) in ECL3 forming a disulfide bond. Further characterization by cell-based assays showed that all mutants are compromised in facilitating sterol uptake, protein stability, and trafficking to the plasma membrane. Our data highlight the fundamental importance of all six extracellular cysteine residues for the functional integrity of Pdr11p and provide new structural insights into the PDR family of transporters.
Collapse
Affiliation(s)
- Lyubomir Dimitrov Stanchev
- Department of Molecular Biochemistry, Faculty of Chemistry and Biochemistry, Ruhr University Bochum, 44801 Bochum, Germany; (L.D.S.); (M.K.)
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg, Denmark; (M.M.); (D.S.); (R.L.L.-M.)
| | - Magdalena Marek
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg, Denmark; (M.M.); (D.S.); (R.L.L.-M.)
| | - Feng Xian
- Proteomics of Cellular Signaling, Luxembourg Institute of Health, Rue Thomas Edison 1A-B, L-1445 Strassen, Luxembourg; (F.X.); (G.D.)
| | - Mara Klöhn
- Department of Molecular Biochemistry, Faculty of Chemistry and Biochemistry, Ruhr University Bochum, 44801 Bochum, Germany; (L.D.S.); (M.K.)
| | - Daniele Silvestro
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg, Denmark; (M.M.); (D.S.); (R.L.L.-M.)
| | - Gunnar Dittmar
- Proteomics of Cellular Signaling, Luxembourg Institute of Health, Rue Thomas Edison 1A-B, L-1445 Strassen, Luxembourg; (F.X.); (G.D.)
| | - Rosa Laura López-Marqués
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg, Denmark; (M.M.); (D.S.); (R.L.L.-M.)
| | - Thomas Günther Pomorski
- Department of Molecular Biochemistry, Faculty of Chemistry and Biochemistry, Ruhr University Bochum, 44801 Bochum, Germany; (L.D.S.); (M.K.)
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg, Denmark; (M.M.); (D.S.); (R.L.L.-M.)
- Correspondence: ; Tel.: +49-234-322-4430
| |
Collapse
|
9
|
Grechko V, Podolsky D, Cheshchevik V. Identification new potential multidrug resistance proteins of Saccharomyces cerevisiae. J Microbiol Methods 2020; 176:106029. [DOI: 10.1016/j.mimet.2020.106029] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Revised: 07/28/2020] [Accepted: 08/06/2020] [Indexed: 10/23/2022]
|
10
|
van 't Klooster JS, Cheng TY, Sikkema HR, Jeucken A, Moody DB, Poolman B. Membrane Lipid Requirements of the Lysine Transporter Lyp1 from Saccharomyces cerevisiae. J Mol Biol 2020; 432:4023-4031. [PMID: 32413406 PMCID: PMC8005870 DOI: 10.1016/j.jmb.2020.04.029] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 04/28/2020] [Accepted: 04/30/2020] [Indexed: 11/25/2022]
Abstract
Membrane lipids act as solvents and functional cofactors for integral membrane proteins. The yeast plasma membrane is unusual in that it may have a high lipid order, which coincides with low passive permeability for small molecules and a slow lateral diffusion of proteins. Yet, membrane proteins whose functions require altered conformation must have flexibility within membranes. We have determined the molecular composition of yeast plasma membrane lipids located within a defined diameter of model proteins, including the APC-superfamily lysine transporter Lyp1. We now use the composition of lipids that naturally surround Lyp1 to guide testing of lipids that support the normal functioning of the transporter, when reconstituted in vesicles of defined lipid composition. We find that phosphatidylserine and ergosterol are essential for Lyp1 function, and the transport activity displays a sigmoidal relationship with the concentration of these lipids. Non-bilayer lipids stimulate transport activity, but different types are interchangeable. Remarkably, Lyp1 requires a relatively high fraction of lipids with one or more unsaturated acyl chains. The transport data and predictions of the periprotein lipidome of Lyp1 support a new model in which a narrow band of lipids immediately surrounding the transmembrane stalk of a model protein allows conformational changes in the protein.
Collapse
Affiliation(s)
- Joury S van 't Klooster
- Department of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747, AG, Groningen, the Netherlands
| | - Tan-Yun Cheng
- Division of Rheumatology, Inflammation and Immunity, Brigham and Women's Hospital, Harvard Medical School, 60 Fenwood Road, Boston, MA 02115, USA
| | - Hendrik R Sikkema
- Department of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747, AG, Groningen, the Netherlands
| | - Aike Jeucken
- Department of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747, AG, Groningen, the Netherlands
| | - D Branch Moody
- Division of Rheumatology, Inflammation and Immunity, Brigham and Women's Hospital, Harvard Medical School, 60 Fenwood Road, Boston, MA 02115, USA; Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
| | - Bert Poolman
- Department of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747, AG, Groningen, the Netherlands.
| |
Collapse
|
11
|
Papay M, Klein C, Hapala I, Petriskova L, Kuchler K, Valachovic M. Mutations in the nucleotide‐binding domain of putative sterol importers Aus1 and Pdr11 selectively affect utilization of exogenous sterol species in yeast. Yeast 2019; 37:5-14. [DOI: 10.1002/yea.3456] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 12/08/2019] [Accepted: 12/10/2019] [Indexed: 11/07/2022] Open
Affiliation(s)
- Marek Papay
- Department of Membrane Biochemistry, Institute of Animal Biochemistry and Genetics Centre of Biosciences of the Slovak Academy of Sciences Bratislava Slovakia
| | - Cornelia Klein
- Center for Medical Biochemistry, Max Perutz Labs Vienna, Campus Vienna Biocenter Medical University of Vienna Vienna Austria
| | - Ivan Hapala
- Department of Membrane Biochemistry, Institute of Animal Biochemistry and Genetics Centre of Biosciences of the Slovak Academy of Sciences Bratislava Slovakia
| | - Livia Petriskova
- Department of Membrane Biochemistry, Institute of Animal Biochemistry and Genetics Centre of Biosciences of the Slovak Academy of Sciences Bratislava Slovakia
| | - Karl Kuchler
- Center for Medical Biochemistry, Max Perutz Labs Vienna, Campus Vienna Biocenter Medical University of Vienna Vienna Austria
| | - Martin Valachovic
- Department of Membrane Biochemistry, Institute of Animal Biochemistry and Genetics Centre of Biosciences of the Slovak Academy of Sciences Bratislava Slovakia
| |
Collapse
|
12
|
Rizzo J, Stanchev LD, da Silva VK, Nimrichter L, Pomorski TG, Rodrigues ML. Role of lipid transporters in fungal physiology and pathogenicity. Comput Struct Biotechnol J 2019; 17:1278-1289. [PMID: 31921394 PMCID: PMC6944739 DOI: 10.1016/j.csbj.2019.09.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 08/20/2019] [Accepted: 09/02/2019] [Indexed: 02/08/2023] Open
Abstract
The fungal cell wall and membrane are the most common targets of antifungal agents, but the potential of membrane lipid organization in regulating drug-target interactions has yet to be investigated. Energy-dependent lipid transporters have been recently associated with virulence and drug resistance in many pathogenic fungi. To illustrate this view, we discuss (i) the structural and biological aspects of ATP-driven lipid transporters, comprising P-type ATPases and ATP-binding cassette transporters, (ii) the role of these transporters in fungal physiology and virulence, and (iii) the potential of lipid transporters as targets for the development of novel antifungals. These recent observations indicate that the lipid-trafficking machinery in fungi is a promising target for studies on physiology, pathogenesis and drug development.
Collapse
Affiliation(s)
- Juliana Rizzo
- Instituto de Microbiologia Paulo de Góes (IMPG), Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
| | - Lyubomir Dimitrov Stanchev
- Department of Molecular Biochemistry, Ruhr University Bochum, Faculty of Chemistry and Biochemistry, 44780 Bochum, Germany
- Department of Plant Biology and Biotechnology, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C,Denmark
| | - Vanessa K.A. da Silva
- Programa de Pós-Graduação em Biologia Parasitária do Instituto Oswaldo Cruz (IOC), Fundação Oswaldo Cruz (Fiocruz), Rio de Janeiro, Brazil
| | - Leonardo Nimrichter
- Instituto de Microbiologia Paulo de Góes (IMPG), Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
| | - Thomas Günther Pomorski
- Department of Molecular Biochemistry, Ruhr University Bochum, Faculty of Chemistry and Biochemistry, 44780 Bochum, Germany
- Department of Plant Biology and Biotechnology, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C,Denmark
| | - Marcio L. Rodrigues
- Instituto de Microbiologia Paulo de Góes (IMPG), Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
- Instituto Carlos Chagas, Fundação Oswaldo Cruz (Fiocruz), Curitiba, Brazil
| |
Collapse
|
13
|
Steady state analysis of influx and transbilayer distribution of ergosterol in the yeast plasma membrane. Theor Biol Med Model 2019; 16:13. [PMID: 31412941 PMCID: PMC6694696 DOI: 10.1186/s12976-019-0108-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 07/15/2019] [Indexed: 01/05/2023] Open
Abstract
Background The transbilayer sterol distribution between both plasma membrane (PM) leaflets has long been debated. Recent studies in mammalian cells and in yeast show that the majority of sterol resides in the inner PM leaflet. Since sterol flip-flop in model membranes is rapid and energy-independent, a mechanistic understanding for net enrichment of sterol in one leaflet is lacking. Import of ergosterol in yeast can take place via the ABC transporters Aus1/Pdr11 under anaerobic growth conditions, eventually followed by rapid non-vesicular sterol transport to the endoplasmic reticulum (ER). Little is known about how these transport steps are dynamically coordinated. Methods Here, a kinetic steady state model is presented which considers sterol import via Aus1/Pdr11, sterol flip-flop across the PM, bi-molecular complex formation and intracellular sterol release followed by eventual transport to and esterification of sterol in the ER. The steady state flux is calculated, and a thermodynamic analysis of feasibility is presented. Results It is shown that the steady state sterol flux across the PM can be entirely controlled by irreversible sterol import via Aus1/Pdr11. The transbilayer sterol flux at steady state is a non-linear function of the chemical potential difference of sterol between both leaflets. Non-vesicular release of sterol on the cytoplasmic side of the PM lowers the attainable sterol enrichment in the inner leaflet. Including complex formation of sterol with phospholipids or proteins can explain several puzzling experimental observations; 1) rapid sterol flip-flop across the PM despite net sterol enrichment in one leaflet, 2) a pronounced steady state sterol gradient between PM and ER despite fast non-vesicular sterol exchange between both compartments and 3) a non-linear dependence of ER sterol on ergosterol abundance in the PM. Conclusions A steady state model is presented that can account for the observed sterol asymmetry in the yeast PM, the strong sterol gradient between PM and ER and threshold-like expansion of ER sterol for increasing sterol influx into the PM. The model also provides new insight into selective uptake of cholesterol and its homeostasis in mammalian cells, and it provides testable predictions for future experiments.
Collapse
|
14
|
Claus S, Jezierska S, Van Bogaert INA. Protein‐facilitated transport of hydrophobic molecules across the yeast plasma membrane. FEBS Lett 2019; 593:1508-1527. [DOI: 10.1002/1873-3468.13469] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2019] [Revised: 05/31/2019] [Accepted: 06/03/2019] [Indexed: 12/15/2022]
Affiliation(s)
- Silke Claus
- Biochemical and Microbial Technology Universiteit Gent Belgium
| | | | - Inge N. A. Van Bogaert
- Lab. of Industrial Microbiology and Biocatalysis Faculty of Bioscience Engineering Ghent University Belgium
| |
Collapse
|
15
|
The lipid head group is the key element for substrate recognition by the P4 ATPase ALA2: a phosphatidylserine flippase. Biochem J 2019; 476:783-794. [PMID: 30755463 PMCID: PMC6402034 DOI: 10.1042/bcj20180891] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 02/05/2019] [Accepted: 02/12/2019] [Indexed: 11/30/2022]
Abstract
Type IV P-type ATPases (P4 ATPases) are lipid flippases that catalyze phospholipid transport from the exoplasmic to the cytoplasmic leaflet of cellular membranes, but the mechanism by which they recognize and transport phospholipids through the lipid bilayer remains unknown. In the present study, we succeeded in purifying recombinant aminophospholipid ATPase 2 (ALA2), a member of the P4 ATPase subfamily in Arabidopsis thaliana, in complex with the ALA-interacting subunit 5 (ALIS5). The ATP hydrolytic activity of the ALA2–ALIS5 complex was stimulated in a highly specific manner by phosphatidylserine. Small changes in the stereochemistry or the functional groups of the phosphatidylserine head group affected enzymatic activity, whereas alteration in the length and composition of the acyl chains only had minor effects. Likewise, the enzymatic activity of the ALA2–ALIS5 complex was stimulated by both mono- and di-acyl phosphatidylserines. Taken together, the results identify the lipid head group as the key structural element for substrate recognition by the P4 ATPase.
Collapse
|
16
|
Li QQ, Tsai HF, Mandal A, Walker BA, Noble JA, Fukuda Y, Bennett JE. Sterol uptake and sterol biosynthesis act coordinately to mediate antifungal resistance in Candida glabrata under azole and hypoxic stress. Mol Med Rep 2018. [PMID: 29532896 PMCID: PMC5928633 DOI: 10.3892/mmr.2018.8716] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Pathogenic fungi, including Candida glabrata, develop strategies to grow and survive both in vitro and in vivo under azole stress. However, the mechanisms by which yeast cells counteract the inhibitory effects of azoles are not completely understood. In the current study, it was demonstrated that the expression of the ergosterol biosynthetic genes ERG2, ERG3, ERG4, ERG10, and ERG11 was significantly upregulated in C. glabrata following fluconazole treatment. Inhibiting ergosterol biosynthesis using fluconazole also increased the expression of the sterol influx transporter AUS1 and the sterol metabolism regulators SUT1 and UPC2 in fungal cells. The microarray study quantified 35 genes with elevated mRNA levels, including AUS1, TIR3, UPC2, and 8 ERG genes, in a C. glabrata mutant strain lacking ERG1, indicating that sterol importing activity is increased to compensate for defective sterol biosynthesis in cells. Bioinformatic analyses further revealed that those differentially expressed genes were involved in multiple cellular processes and biological functions, such as sterol biosynthesis, lipid localization, and sterol transport. Finally, to assess whether sterol uptake affects yeast susceptibility to azoles, we generated a C. glabrata aus1∆ mutant strain. It was shown that loss of Aus1p in C. glabrata sensitized the pathogen to azoles and enhanced the efficacy of drug exposure under low oxygen tension. In contrast, the presence of exogenous cholesterol or ergosterol in medium rendered the C. glabrata AUS1 wild-type strain highly resistant to fluconazole and voriconazole, suggesting that the sterol importing mechanism is augmented when ergosterol biosynthesis is suppressed in the cell, thus allowing C. glabrata to survive under azole pressure. On the basis of these results, it was concluded that sterol uptake and sterol biosynthesis may act coordinately and collaboratively to sustain growth and to mediate antifungal resistance in C. glabrata through dynamic gene expression in response to azole stress and environmental challenges.
Collapse
Affiliation(s)
- Qingdi Quentin Li
- Clinical Mycology Section, Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Huei-Fung Tsai
- Clinical Mycology Section, Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Ajeet Mandal
- Molecular and Cellular Biochemistry Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA
| | - Bryan A Walker
- Clinical Mycology Section, Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jason A Noble
- Clinical Mycology Section, Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Yuichi Fukuda
- Clinical Mycology Section, Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - John E Bennett
- Clinical Mycology Section, Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| |
Collapse
|
17
|
Laub KR, Marek M, Stanchev LD, Herrera SA, Kanashova T, Bourmaud A, Dittmar G, Günther Pomorski T. Purification and characterisation of the yeast plasma membrane ATP binding cassette transporter Pdr11p. PLoS One 2017; 12:e0184236. [PMID: 28922409 PMCID: PMC5602531 DOI: 10.1371/journal.pone.0184236] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Accepted: 08/21/2017] [Indexed: 12/27/2022] Open
Abstract
The ATP binding cassette (ABC) transporters Pdr11p and its paralog Aus1p are expressed under anaerobic growth conditions at the plasma membrane of the yeast Saccharomyces cerevisiae and are required for sterol uptake. However, the precise mechanism by which these ABC transporters facilitate sterol movement is unknown. In this study, an overexpression and purification procedure was developed with the aim to characterise the Pdr11p transporter. Engineering of Pdr11p variants fused at the C terminus with green fluorescent protein (Pdr11p-GFP) and containing a FLAG tag at the N terminus facilitated expression analysis and one-step purification, respectively. The detergent-solubilised and purified protein displayed a stable ATPase activity with a broad pH optimum near 7.4. Mutagenesis of the conserved lysine to methionine (K788M) in the Walker A motif abolished ATP hydrolysis. Remarkably, and in contrast to Aus1p, ATPase activity of Pdr11p was insensitive to orthovanadate and not specifically stimulated by phosphatidylserine upon reconstitution into liposomes. Our results highlight distinct differences between Pdr11p and Aus1p and create an experimental basis for further biochemical studies of both ABC transporters to elucidate their function.
Collapse
Affiliation(s)
- Katrine Rude Laub
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg C, Denmark
| | - Magdalena Marek
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg C, Denmark
| | - Lyubomir Dimitrov Stanchev
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg C, Denmark
- Department of Molecular Biochemistry, Ruhr University Bochum, Bochum, Germany
| | - Sara Abad Herrera
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg C, Denmark
- Department of Molecular Biochemistry, Ruhr University Bochum, Bochum, Germany
| | - Tamara Kanashova
- Mass spectrometry core unit, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Adèle Bourmaud
- Proteome and Genome research laboratory, Luxembourg Institute of Health, Strassen, Luxembourg
| | - Gunnar Dittmar
- Mass spectrometry core unit, Max Delbrück Center for Molecular Medicine, Berlin, Germany
- Proteome and Genome research laboratory, Luxembourg Institute of Health, Strassen, Luxembourg
| | - Thomas Günther Pomorski
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg C, Denmark
- Department of Molecular Biochemistry, Ruhr University Bochum, Bochum, Germany
- * E-mail:
| |
Collapse
|
18
|
Toussaint F, Pierman B, Bertin A, Lévy D, Boutry M. Purification and biochemical characterization of NpABCG5/NpPDR5, a plant pleiotropic drug resistance transporter expressed in Nicotiana tabacum BY-2 suspension cells. Biochem J 2017; 474:1689-1703. [PMID: 28298475 DOI: 10.1042/bcj20170108] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Revised: 03/13/2017] [Accepted: 03/15/2017] [Indexed: 11/17/2022]
Abstract
Pleiotropic drug resistance (PDR) transporters belong to the ABCG subfamily of ATP-binding cassette (ABC) transporters and are involved in the transport of various molecules across plasma membranes. During evolution, PDR genes appeared independently in fungi and in plants from a duplication of a half-size ABC gene. The enzymatic properties of purified PDR transporters from yeast have been characterized. This is not the case for any plant PDR transporter, or, incidentally, for any purified plant ABC transporter. Yet, plant PDR transporters play important roles in plant physiology such as hormone signaling or resistance to pathogens or herbivores. Here, we describe the expression, purification, enzymatic characterization and 2D analysis by electron microscopy of NpABCG5/NpPDR5 from Nicotiana plumbaginifolia, which has been shown to be involved in the plant defense against herbivores. We constitutively expressed NpABCG5/NpPDR5, provided with a His-tag in a homologous system: suspension cells from Nicotiana tabacum (Bright Yellow 2 line). NpABCG5/NpPDR5 was targeted to the plasma membrane and was solubilized by dodecyl maltoside and purified by Ni-affinity chromatography. The ATP-hydrolyzing specific activity (27 nmol min-1 mg-1) was stimulated seven-fold in the presence of 0.1% asolectin. Electron microscopy analysis indicated that NpABCG5/NpPDR5 is monomeric and with dimensions shorter than those of known ABC transporters. Enzymatic data (optimal pH and sensitivity to inhibitors) confirmed that plant and fungal PDR transporters have different properties. These data also show that N. tabacum suspension cells are a convenient host for the purification and biochemical characterization of ABC transporters.
Collapse
MESH Headings
- ATP Binding Cassette Transporter, Subfamily G, Member 5/chemistry
- ATP Binding Cassette Transporter, Subfamily G, Member 5/genetics
- ATP Binding Cassette Transporter, Subfamily G, Member 5/isolation & purification
- ATP Binding Cassette Transporter, Subfamily G, Member 5/metabolism
- Adenosine Triphosphatases/chemistry
- Adenosine Triphosphatases/genetics
- Adenosine Triphosphatases/isolation & purification
- Adenosine Triphosphatases/metabolism
- Adenosine Triphosphate/metabolism
- Batch Cell Culture Techniques
- Bioreactors
- Cell Membrane/drug effects
- Cell Membrane/metabolism
- Cell Membrane/ultrastructure
- Cells, Cultured
- Chromatography, Affinity
- Detergents/chemistry
- Glucosides/chemistry
- Hydrogen-Ion Concentration
- Image Processing, Computer-Assisted
- Membrane Transport Modulators/pharmacology
- Microscopy, Electron
- Molecular Weight
- Phosphatidylcholines/chemistry
- Plant Proteins/chemistry
- Plant Proteins/genetics
- Plant Proteins/isolation & purification
- Plant Proteins/metabolism
- Protein Conformation
- Protein Transport/drug effects
- Recombinant Fusion Proteins/chemistry
- Recombinant Fusion Proteins/isolation & purification
- Recombinant Fusion Proteins/metabolism
- Solubility
- Nicotiana/cytology
- Nicotiana/enzymology
- Nicotiana/metabolism
Collapse
Affiliation(s)
- Frédéric Toussaint
- Institut des Sciences de la Vie, Université catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium
| | - Baptiste Pierman
- Institut des Sciences de la Vie, Université catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium
| | - Aurélie Bertin
- Laboratoire Physico Chimie Curie, Institut Curie, PSL Research University, CNRS UMR168, 75005 Paris, France
- Sorbonne Universités, UPMC Univ Paris 06, 75005 Paris, France
| | - Daniel Lévy
- Laboratoire Physico Chimie Curie, Institut Curie, PSL Research University, CNRS UMR168, 75005 Paris, France
- Sorbonne Universités, UPMC Univ Paris 06, 75005 Paris, France
| | - Marc Boutry
- Institut des Sciences de la Vie, Université catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium
| |
Collapse
|
19
|
Assay of Flippase Activity in Proteoliposomes Using Fluorescent Lipid Derivatives. Methods Mol Biol 2016; 1377:181-91. [PMID: 26695033 DOI: 10.1007/978-1-4939-3179-8_18] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Specific membrane proteins, termed lipid flippases, play a central role in facilitating the movement of lipids across cellular membranes. In this protocol, we describe the reconstitution of ATP-driven lipid flippases in liposomes and the analysis of their in vitro flippase activity based on the use of fluorescent lipid derivatives. Working with purified and reconstituted systems provides a well-defined experimental setup and allows to directly characterize these membrane proteins at the molecular level.
Collapse
|
20
|
Jørgensen IL, Kemmer GC, Pomorski TG. Membrane protein reconstitution into giant unilamellar vesicles: a review on current techniques. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2016; 46:103-119. [DOI: 10.1007/s00249-016-1155-9] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 06/18/2016] [Accepted: 07/03/2016] [Indexed: 12/11/2022]
|
21
|
Jensen MS, Costa SR, Theorin L, Christensen JP, Pomorski TG, López-Marqués RL. Application of image cytometry to characterize heterologous lipid flippases in yeast. Cytometry A 2016; 89:673-80. [PMID: 27272389 DOI: 10.1002/cyto.a.22886] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Lipid flippases are integral membrane proteins that play a central role in moving lipids across cellular membranes. Some of these transporters are ATPases that couple lipid translocation to ATP hydrolysis, whereas others function without any discernible metabolic energy input. A growing number of lipid flippases has been identified but key features of their activity remain to be elucidated. A well-established method to characterize ATP-driven flippases is based on their heterologous expression in yeast, followed by incubation of the cells with fluorescent lipids. Internalization of these probes is typically monitored by flow cytometry, a costly and maintenance-intensive method. Here, we have optimized a protocol to use an automated image-based cell counter to accurately measure lipid uptake by heterologous lipid flippases expressed in yeast. The method was validated by comparison with the classical flow cytometric evaluation of lipid-labeled cells. In addition, we demonstrated that expression of fluorescently tagged flippase complexes can be directly co-related with fluorescent lipid uptake using the image-based cell counter system. The method extends the number of techniques available for characterization of lipid flippase activity, and should be readily adaptable to analyze a variety of other transport systems in yeast, parasites, and mammalian cells. © 2016 International Society for Advancement of Cytometry.
Collapse
Affiliation(s)
- Maria S Jensen
- Centre for Membrane Pumps in Cells and Disease - PUMPKIN, Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg C, Denmark
| | - Sara R Costa
- Centre for Membrane Pumps in Cells and Disease - PUMPKIN, Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg C, Denmark
| | - Lisa Theorin
- Centre for Membrane Pumps in Cells and Disease - PUMPKIN, Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg C, Denmark
| | | | - Thomas Günther Pomorski
- Centre for Membrane Pumps in Cells and Disease - PUMPKIN, Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg C, Denmark
- Faculty of Chemistry and Biochemistry, Department of Molecular Biochemistry, Ruhr University Bochum, Universitätstrasse 150, Bochum, D-44780, Germany
| | - Rosa L López-Marqués
- Centre for Membrane Pumps in Cells and Disease - PUMPKIN, Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg C, Denmark
| |
Collapse
|
22
|
Wüstner D, Lund FW, Röhrl C, Stangl H. Potential of BODIPY-cholesterol for analysis of cholesterol transport and diffusion in living cells. Chem Phys Lipids 2016; 194:12-28. [DOI: 10.1016/j.chemphyslip.2015.08.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Revised: 08/07/2015] [Accepted: 08/12/2015] [Indexed: 01/04/2023]
|
23
|
Gulati S, Balderes D, Kim C, Guo ZA, Wilcox L, Area-Gomez E, Snider J, Wolinski H, Stagljar I, Granato JT, Ruggles KV, DeGiorgis JA, Kohlwein SD, Schon EA, Sturley SL. ATP-binding cassette transporters and sterol O-acyltransferases interact at membrane microdomains to modulate sterol uptake and esterification. FASEB J 2015. [PMID: 26220175 DOI: 10.1096/fj.14-264796] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A key component of eukaryotic lipid homeostasis is the esterification of sterols with fatty acids by sterol O-acyltransferases (SOATs). The esterification reactions are allosterically activated by their sterol substrates, the majority of which accumulate at the plasma membrane. We demonstrate that in yeast, sterol transport from the plasma membrane to the site of esterification is associated with the physical interaction of the major SOAT, acyl-coenzyme A:cholesterol acyltransferase (ACAT)-related enzyme (Are)2p, with 2 plasma membrane ATP-binding cassette (ABC) transporters: Aus1p and Pdr11p. Are2p, Aus1p, and Pdr11p, unlike the minor acyltransferase, Are1p, colocalize to sterol and sphingolipid-enriched, detergent-resistant microdomains (DRMs). Deletion of either ABC transporter results in Are2p relocalization to detergent-soluble membrane domains and a significant decrease (53-36%) in esterification of exogenous sterol. Similarly, in murine tissues, the SOAT1/Acat1 enzyme and activity localize to DRMs. This subcellular localization is diminished upon deletion of murine ABC transporters, such as Abcg1, which itself is DRM associated. We propose that the close proximity of sterol esterification and transport proteins to each other combined with their residence in lipid-enriched membrane microdomains facilitates rapid, high-capacity sterol transport and esterification, obviating any requirement for soluble intermediary proteins.
Collapse
Affiliation(s)
- Sonia Gulati
- *Institute of Human Nutrition, Department of Neurology, **Department of Genetics and Development, and Department of Pediatrics, Columbia University Medical Center, New York, New York, USA; Department of Biological Sciences and Department of Chemistry, Columbia University, New York, New York, USA; Donnelly Center for Cellular and Biomolecular Research, Toronto, Ontario, Canada; Institute of Molecular Biosciences, BioTechMed Graz, University of Graz, Graz, Austria; Department of Biology, Providence College, Providence, Rhode Island, USA; and Marine Biological Laboratory, Woods Hole, Massachusetts, USA
| | - Dina Balderes
- *Institute of Human Nutrition, Department of Neurology, **Department of Genetics and Development, and Department of Pediatrics, Columbia University Medical Center, New York, New York, USA; Department of Biological Sciences and Department of Chemistry, Columbia University, New York, New York, USA; Donnelly Center for Cellular and Biomolecular Research, Toronto, Ontario, Canada; Institute of Molecular Biosciences, BioTechMed Graz, University of Graz, Graz, Austria; Department of Biology, Providence College, Providence, Rhode Island, USA; and Marine Biological Laboratory, Woods Hole, Massachusetts, USA
| | - Christine Kim
- *Institute of Human Nutrition, Department of Neurology, **Department of Genetics and Development, and Department of Pediatrics, Columbia University Medical Center, New York, New York, USA; Department of Biological Sciences and Department of Chemistry, Columbia University, New York, New York, USA; Donnelly Center for Cellular and Biomolecular Research, Toronto, Ontario, Canada; Institute of Molecular Biosciences, BioTechMed Graz, University of Graz, Graz, Austria; Department of Biology, Providence College, Providence, Rhode Island, USA; and Marine Biological Laboratory, Woods Hole, Massachusetts, USA
| | - Zhongmin A Guo
- *Institute of Human Nutrition, Department of Neurology, **Department of Genetics and Development, and Department of Pediatrics, Columbia University Medical Center, New York, New York, USA; Department of Biological Sciences and Department of Chemistry, Columbia University, New York, New York, USA; Donnelly Center for Cellular and Biomolecular Research, Toronto, Ontario, Canada; Institute of Molecular Biosciences, BioTechMed Graz, University of Graz, Graz, Austria; Department of Biology, Providence College, Providence, Rhode Island, USA; and Marine Biological Laboratory, Woods Hole, Massachusetts, USA
| | - Lisa Wilcox
- *Institute of Human Nutrition, Department of Neurology, **Department of Genetics and Development, and Department of Pediatrics, Columbia University Medical Center, New York, New York, USA; Department of Biological Sciences and Department of Chemistry, Columbia University, New York, New York, USA; Donnelly Center for Cellular and Biomolecular Research, Toronto, Ontario, Canada; Institute of Molecular Biosciences, BioTechMed Graz, University of Graz, Graz, Austria; Department of Biology, Providence College, Providence, Rhode Island, USA; and Marine Biological Laboratory, Woods Hole, Massachusetts, USA
| | - Estela Area-Gomez
- *Institute of Human Nutrition, Department of Neurology, **Department of Genetics and Development, and Department of Pediatrics, Columbia University Medical Center, New York, New York, USA; Department of Biological Sciences and Department of Chemistry, Columbia University, New York, New York, USA; Donnelly Center for Cellular and Biomolecular Research, Toronto, Ontario, Canada; Institute of Molecular Biosciences, BioTechMed Graz, University of Graz, Graz, Austria; Department of Biology, Providence College, Providence, Rhode Island, USA; and Marine Biological Laboratory, Woods Hole, Massachusetts, USA
| | - Jamie Snider
- *Institute of Human Nutrition, Department of Neurology, **Department of Genetics and Development, and Department of Pediatrics, Columbia University Medical Center, New York, New York, USA; Department of Biological Sciences and Department of Chemistry, Columbia University, New York, New York, USA; Donnelly Center for Cellular and Biomolecular Research, Toronto, Ontario, Canada; Institute of Molecular Biosciences, BioTechMed Graz, University of Graz, Graz, Austria; Department of Biology, Providence College, Providence, Rhode Island, USA; and Marine Biological Laboratory, Woods Hole, Massachusetts, USA
| | - Heimo Wolinski
- *Institute of Human Nutrition, Department of Neurology, **Department of Genetics and Development, and Department of Pediatrics, Columbia University Medical Center, New York, New York, USA; Department of Biological Sciences and Department of Chemistry, Columbia University, New York, New York, USA; Donnelly Center for Cellular and Biomolecular Research, Toronto, Ontario, Canada; Institute of Molecular Biosciences, BioTechMed Graz, University of Graz, Graz, Austria; Department of Biology, Providence College, Providence, Rhode Island, USA; and Marine Biological Laboratory, Woods Hole, Massachusetts, USA
| | - Igor Stagljar
- *Institute of Human Nutrition, Department of Neurology, **Department of Genetics and Development, and Department of Pediatrics, Columbia University Medical Center, New York, New York, USA; Department of Biological Sciences and Department of Chemistry, Columbia University, New York, New York, USA; Donnelly Center for Cellular and Biomolecular Research, Toronto, Ontario, Canada; Institute of Molecular Biosciences, BioTechMed Graz, University of Graz, Graz, Austria; Department of Biology, Providence College, Providence, Rhode Island, USA; and Marine Biological Laboratory, Woods Hole, Massachusetts, USA
| | - Juliana T Granato
- *Institute of Human Nutrition, Department of Neurology, **Department of Genetics and Development, and Department of Pediatrics, Columbia University Medical Center, New York, New York, USA; Department of Biological Sciences and Department of Chemistry, Columbia University, New York, New York, USA; Donnelly Center for Cellular and Biomolecular Research, Toronto, Ontario, Canada; Institute of Molecular Biosciences, BioTechMed Graz, University of Graz, Graz, Austria; Department of Biology, Providence College, Providence, Rhode Island, USA; and Marine Biological Laboratory, Woods Hole, Massachusetts, USA
| | - Kelly V Ruggles
- *Institute of Human Nutrition, Department of Neurology, **Department of Genetics and Development, and Department of Pediatrics, Columbia University Medical Center, New York, New York, USA; Department of Biological Sciences and Department of Chemistry, Columbia University, New York, New York, USA; Donnelly Center for Cellular and Biomolecular Research, Toronto, Ontario, Canada; Institute of Molecular Biosciences, BioTechMed Graz, University of Graz, Graz, Austria; Department of Biology, Providence College, Providence, Rhode Island, USA; and Marine Biological Laboratory, Woods Hole, Massachusetts, USA
| | - Joseph A DeGiorgis
- *Institute of Human Nutrition, Department of Neurology, **Department of Genetics and Development, and Department of Pediatrics, Columbia University Medical Center, New York, New York, USA; Department of Biological Sciences and Department of Chemistry, Columbia University, New York, New York, USA; Donnelly Center for Cellular and Biomolecular Research, Toronto, Ontario, Canada; Institute of Molecular Biosciences, BioTechMed Graz, University of Graz, Graz, Austria; Department of Biology, Providence College, Providence, Rhode Island, USA; and Marine Biological Laboratory, Woods Hole, Massachusetts, USA
| | - Sepp D Kohlwein
- *Institute of Human Nutrition, Department of Neurology, **Department of Genetics and Development, and Department of Pediatrics, Columbia University Medical Center, New York, New York, USA; Department of Biological Sciences and Department of Chemistry, Columbia University, New York, New York, USA; Donnelly Center for Cellular and Biomolecular Research, Toronto, Ontario, Canada; Institute of Molecular Biosciences, BioTechMed Graz, University of Graz, Graz, Austria; Department of Biology, Providence College, Providence, Rhode Island, USA; and Marine Biological Laboratory, Woods Hole, Massachusetts, USA
| | - Eric A Schon
- *Institute of Human Nutrition, Department of Neurology, **Department of Genetics and Development, and Department of Pediatrics, Columbia University Medical Center, New York, New York, USA; Department of Biological Sciences and Department of Chemistry, Columbia University, New York, New York, USA; Donnelly Center for Cellular and Biomolecular Research, Toronto, Ontario, Canada; Institute of Molecular Biosciences, BioTechMed Graz, University of Graz, Graz, Austria; Department of Biology, Providence College, Providence, Rhode Island, USA; and Marine Biological Laboratory, Woods Hole, Massachusetts, USA
| | - Stephen L Sturley
- *Institute of Human Nutrition, Department of Neurology, **Department of Genetics and Development, and Department of Pediatrics, Columbia University Medical Center, New York, New York, USA; Department of Biological Sciences and Department of Chemistry, Columbia University, New York, New York, USA; Donnelly Center for Cellular and Biomolecular Research, Toronto, Ontario, Canada; Institute of Molecular Biosciences, BioTechMed Graz, University of Graz, Graz, Austria; Department of Biology, Providence College, Providence, Rhode Island, USA; and Marine Biological Laboratory, Woods Hole, Massachusetts, USA
| |
Collapse
|
24
|
A subset of annular lipids is linked to the flippase activity of an ABC transporter. Nat Chem 2015; 7:255-62. [DOI: 10.1038/nchem.2172] [Citation(s) in RCA: 102] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Accepted: 12/19/2014] [Indexed: 12/18/2022]
|
25
|
Marek M, Silvestro D, Fredslund MD, Andersen TG, Pomorski TG. Serum albumin promotes ATP-binding cassette transporter-dependent sterol uptake in yeast. FEMS Yeast Res 2014; 14:1223-33. [DOI: 10.1111/1567-1364.12219] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Revised: 09/21/2014] [Accepted: 10/08/2014] [Indexed: 12/23/2022] Open
Affiliation(s)
- Magdalena Marek
- Centre for Membrane Pumps in Cells and Disease - PUMPKIN; Department of Plant and Environmental Sciences; University of Copenhagen; Frederiksberg C Denmark
| | - Daniele Silvestro
- Copenhagen Plant Science Center and the VILLUM Research Center ‘Plant Plasticity’; Department of Plant and Environmental Sciences; University of Copenhagen; Frederiksberg C, Copenhagen Denmark
| | - Maria D. Fredslund
- Centre for Membrane Pumps in Cells and Disease - PUMPKIN; Department of Plant and Environmental Sciences; University of Copenhagen; Frederiksberg C Denmark
| | - Tonni G. Andersen
- Department of Plant Molecular Biology, Biophore, UNIL-Sorge; University of Lausanne; Lausanne Switzerland
| | - Thomas G. Pomorski
- Centre for Membrane Pumps in Cells and Disease - PUMPKIN; Department of Plant and Environmental Sciences; University of Copenhagen; Frederiksberg C Denmark
| |
Collapse
|
26
|
Yeast ABC proteins involved in multidrug resistance. Cell Mol Biol Lett 2013; 19:1-22. [PMID: 24297686 PMCID: PMC6275743 DOI: 10.2478/s11658-013-0111-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Accepted: 11/27/2013] [Indexed: 01/03/2023] Open
Abstract
Pleiotropic drug resistance is a complex phenomenon that involves many proteins that together create a network. One of the common mechanisms of multidrug resistance in eukaryotic cells is the active efflux of a broad range of xenobiotics through ATP-binding cassette (ABC) transporters. Saccharomyces cerevisiae is often used as a model to study such activity because of the functional and structural similarities of its ABC transporters to mammalian ones. Numerous ABC transporters are found in humans and some are associated with the resistance of tumors to chemotherapeutics. Efflux pump modulators that change the activity of ABC proteins are the most promising candidate drugs to overcome such resistance. These modulators can be chemically synthesized or isolated from natural sources (e.g., plant alkaloids) and might also be used in the treatment of fungal infections. There are several generations of synthetic modulators that differ in specificity, toxicity and effectiveness, and are often used for other clinical effects.
Collapse
|
27
|
Xiao Y, Guo L, Wang Y. Isotope-coded ATP probe for quantitative affinity profiling of ATP-binding proteins. Anal Chem 2013; 85:7478-86. [PMID: 23841533 DOI: 10.1021/ac401415z] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
ATP-binding proteins play significant roles in numerous cellular processes. Here, we introduced a novel isotope-coded ATP-affinity probe (ICAP) as an acylating agent to simultaneously enrich and incorporate isotope label to ATP-binding proteins. By taking advantage of the quantitative capability of this isotope-coded probe, we devised an affinity profiling strategy to comprehensively characterize ATP-protein interactions at the entire proteome scale. False-positive identification of ATP-binding sites derived from nonspecific labeling was effectively minimized through the comparison of the labeling behaviors of lysine residues with the use of low and high concentrations of the ICAP reagents. A total of 258 previously known ATP-binding proteins from lysates of HeLa-S3 and Jurkat-T cells were validated with this affinity profiling assay. Additionally, we demonstrated that this novel quantitative ATP-affinity profiling strategy is particularly useful for unveiling previously unrecognized nucleotide-binding sites in ATP-binding proteins. For example, our profiling results revealed K356 as a new ATP-binding site in HSP90. Furthermore, 293 proteins without documented ATP-binding GO were predicted to be ATP-binding proteins on the basis of our quantitative affinity profiling results. We also uncovered, for the first time, the ATP-binding capability of human proliferating cell nuclear antigen (PCNA), identified the lysine residue involved in ATP binding, and validated the protein's capacity in ATP binding with an independent assay. The ICAP approach described in the present paper should be generally applicable for the quantitative assessment of ATP-binding proteins in proteomic samples from cells and tissues.
Collapse
Affiliation(s)
- Yongsheng Xiao
- Department of Chemistry, University of California, Riverside, California 92521-0403, United States
| | | | | |
Collapse
|
28
|
Wriessnegger T, Pichler H. Yeast metabolic engineering – Targeting sterol metabolism and terpenoid formation. Prog Lipid Res 2013; 52:277-93. [DOI: 10.1016/j.plipres.2013.03.001] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2012] [Revised: 03/26/2013] [Accepted: 03/27/2013] [Indexed: 12/28/2022]
|
29
|
Faletrov YV, Frolova NS, Hlushko HV, Rudaya EV, Edimecheva IP, Mauersberger S, Shkumatov VM. Evaluation of the fluorescent probes Nile Red and 25-NBD-cholesterol as substrates for steroid-converting oxidoreductases using pure enzymes and microorganisms. FEBS J 2013; 280:3109-19. [DOI: 10.1111/febs.12265] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Revised: 03/21/2013] [Accepted: 03/21/2013] [Indexed: 11/30/2022]
Affiliation(s)
- Yaroslav V. Faletrov
- Research Institute for Physical Chemical Problems; Belarusian State University; Minsk; Belarus
| | - Nina S. Frolova
- Research Institute for Physical Chemical Problems; Belarusian State University; Minsk; Belarus
| | - Hanna V. Hlushko
- Research Institute for Physical Chemical Problems; Belarusian State University; Minsk; Belarus
| | - Elena V. Rudaya
- Research Institute for Physical Chemical Problems; Belarusian State University; Minsk; Belarus
| | - Irina P. Edimecheva
- Research Institute for Physical Chemical Problems; Belarusian State University; Minsk; Belarus
| | | | | |
Collapse
|
30
|
Nagi M, Tanabe K, Ueno K, Nakayama H, Aoyama T, Chibana H, Yamagoe S, Umeyama T, Oura T, Ohno H, Kajiwara S, Miyazaki Y. The Candida glabrata sterol scavenging mechanism, mediated by the ATP-binding cassette transporter Aus1p, is regulated by iron limitation. Mol Microbiol 2013; 88:371-81. [PMID: 23448689 DOI: 10.1111/mmi.12189] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/19/2013] [Indexed: 11/26/2022]
Abstract
During disseminated infection by the opportunistic pathogen Candida glabrata, uptake of sterols such as serum cholesterol may play a significant role during pathogenesis. The ATP-binding cassette transporter Aus1p is thought to function as a sterol importer and in this study, we show that uptake of exogenous sterols occurred under anaerobic conditions in wild-type cells of C. glabrata but not in AUS1-deleted mutant (aus1Δ) cells. In aerobic cultures, growth inhibition by fluconazole was prevented in the presence of serum, and AUS1 expression was upregulated. Uptake of sterol by azole treated cells required the presence of serum, and sterol alone did not reverse FLC inhibition of growth. However, if iron availability in the growth medium was limited by addition of the iron chelators ferrozine or apo-transferrin, growth of wild-type cells, but not aus1Δ cells, was rescued. In a mouse model of disseminated infection, the C. glabrata aus1Δ strain caused a significantly decreased kidney fungal burden than the wild-type strain or a strain in which AUS1 was restored. We conclude that sterol uptake in C. glabrata can occur in iron poor environment of host tissues and thus may contribute to C. glabrata pathogenesis.
Collapse
Affiliation(s)
- Minoru Nagi
- Department of Chemotherapy and Mycoses, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
31
|
Barrera NP, Zhou M, Robinson CV. The role of lipids in defining membrane protein interactions: insights from mass spectrometry. Trends Cell Biol 2012; 23:1-8. [PMID: 22980035 DOI: 10.1016/j.tcb.2012.08.007] [Citation(s) in RCA: 119] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Revised: 08/14/2012] [Accepted: 08/14/2012] [Indexed: 12/19/2022]
Abstract
Cellular membranes comprise hundreds of lipids in which protein complexes, such as ion channels, receptors, and scaffolding complexes, are embedded. These protein assemblies act as signalling and trafficking platforms for processes fundamental to life. Much effort in recent years has focused on identifying the protein components of these complexes after their extraction from the lipid membrane in detergent micelles. Spectacular advances have been made using X-ray crystallography, providing in some cases detailed information about the mechanism of pumping and channel gating. These structural studies are leading to a growing realisation that, to understand their function, it is not only the structures of the protein components that are important but also knowledge of the protein-lipid interactions. This review highlights recent insights gained from this knowledge, surveys methods being developed for probing these interactions, and focuses specifically on the potential of mass spectrometry in this growing area of research.
Collapse
Affiliation(s)
- Nelson P Barrera
- Department of Physiology, Pontificia Universidad Católica de Chile, Alameda 340, Santiago, 8331150, Chile.
| | | | | |
Collapse
|