1
|
Phospholipid effects on SGLT1-mediated glucose transport in rabbit ileum brush border membrane vesicles. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2019; 1861:182985. [PMID: 31082355 DOI: 10.1016/j.bbamem.2019.05.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 04/23/2019] [Accepted: 05/08/2019] [Indexed: 11/20/2022]
Abstract
In small intestine, sodium-glucose cotransporter SGLT1 provides the main mechanism for sugar uptake. We investigated the effect of membrane phospholipids (PL) on this transport in rabbit ileal brush border membrane vesicles (BBMV). For this, PL of different charge, length, and saturation were incorporated into BBMV. Transport was measured related to (i) membrane surface charge (membrane-bound MC540 fluorescence), (ii) membrane thickness (PL incorporation of different acyl chain length), and (iii) membrane fluidity (r12AS, fluorescence anisotropy of 12-AS). Compared to phosphatidylcholine (PC) carrying a neutral head group, inhibition of SGLT1 increased considerably with the acidic phosphatidic acid (PA) and phosphatidylinositol (PI) that increase membrane negative surface charge. The order of PL potency was PI>PA > PE = PS > PC. Inhibition by acidic PA-oleate was 5-times more effective than with neutral PE (phosphatidylethanolamine)-oleate. Lineweaver-Burk plot indicated uncompetitive inhibition of SGLT1 by PA. When membrane thickness was increased by neutral PC of varying acyl chain length, transport was increasingly inhibited by 16:1 PC to 22:1 PC. Even more pronounced inhibition was observed with mono-unsaturated instead of saturated acyl chains which increased membrane fluidity (indicated by decreased r12AS). In conclusion, sodium-dependent glucose transport of rabbit ileal BBMV is modulated by (i) altered membrane surface charge, (ii) length of acyl chains via membrane thickness, and (iii) saturation of PL acyl chains altering membrane fluidity. Transport was attenuated by charged PL with longer and unsaturated acyl residues. Alterations of PL may provide a principle for attenuating dietary glucose uptake.
Collapse
|
2
|
Suades A, Alcaraz A, Cruz E, Álvarez-Marimon E, Whitelegge JP, Manyosa J, Cladera J, Perálvarez-Marín A. Structural biology workflow for the expression and characterization of functional human sodium glucose transporter type 1 in Pichia pastoris. Sci Rep 2019; 9:1203. [PMID: 30718602 PMCID: PMC6362292 DOI: 10.1038/s41598-018-37445-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 12/04/2018] [Indexed: 12/24/2022] Open
Abstract
Heterologous expression of human membrane proteins is a challenge in structural biology towards drug discovery. Here we report a complete expression and purification process of a functional human sodium/D-glucose co-transporter 1 (hSGLT1) in Pichia pastoris as representative example of a useful strategy for any human membrane protein. hSGLT1 gene was cloned in two different plasmids to develop parallel strategies: one which includes green fluorescent protein fusion for screening optimal conditions, and another for large scale protein production for structural biology and biophysics studies. Our strategy yields at least 1 mg of monodisperse purified recombinant hSGLT1 per liter of culture, which can be characterized by circular dichroism and infrared spectroscopy as an alpha-helical fold protein. This purified hSGLT1 transports co-substrates (Na+ and glucose) and it is inhibited by phlorizin in electrophysiological experiments performed in planar lipid membranes.
Collapse
Affiliation(s)
- Albert Suades
- Biophysics Unit, Department of Biochemistry and Molecular Biology, School of Medicine, Universitat Autònoma de Barcelona, 08193, Cerdanyola del Vallés, Catalonia, Spain.,Department of Biochemistry and Biophysics, Stockholm University, SE-10691, Stockholm, Sweden
| | - Antonio Alcaraz
- Laboratory of Molecular Biophysics, Department of Physics, Universitat Jaume I, 12071, Castellón, Spain
| | - Esteban Cruz
- Biophysics Unit, Department of Biochemistry and Molecular Biology, School of Medicine, Universitat Autònoma de Barcelona, 08193, Cerdanyola del Vallés, Catalonia, Spain
| | - Elena Álvarez-Marimon
- Biophysics Unit, Department of Biochemistry and Molecular Biology, School of Medicine, Universitat Autònoma de Barcelona, 08193, Cerdanyola del Vallés, Catalonia, Spain
| | - Julian P Whitelegge
- The Pasarow Mass Spectrometry Laboratory, The NPI-Semel Institute, David Geffen School of Medicine, UCLA, 760 Westwood Plaza, Los Angeles, CA, 90095, USA
| | - Joan Manyosa
- Biophysics Unit, Department of Biochemistry and Molecular Biology, School of Medicine, Universitat Autònoma de Barcelona, 08193, Cerdanyola del Vallés, Catalonia, Spain
| | - Josep Cladera
- Biophysics Unit, Department of Biochemistry and Molecular Biology, School of Medicine, Universitat Autònoma de Barcelona, 08193, Cerdanyola del Vallés, Catalonia, Spain
| | - Alex Perálvarez-Marín
- Biophysics Unit, Department of Biochemistry and Molecular Biology, School of Medicine, Universitat Autònoma de Barcelona, 08193, Cerdanyola del Vallés, Catalonia, Spain.
| |
Collapse
|
3
|
Neundlinger I, Puntheeranurak T, Wildling L, Rankl C, Wang LX, Gruber HJ, Kinne RKH, Hinterdorfer P. Forces and dynamics of glucose and inhibitor binding to sodium glucose co-transporter SGLT1 studied by single molecule force spectroscopy. J Biol Chem 2014; 289:21673-83. [PMID: 24962566 DOI: 10.1074/jbc.m113.529875] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Single molecule force spectroscopy was employed to investigate the dynamics of the sodium glucose co-transporter (SGLT1) upon substrate and inhibitor binding on the single molecule level. CHO cells stably expressing rbSGLT1 were probed by using atomic force microscopy tips carrying either thioglucose, 2'-aminoethyl β-d-glucopyranoside, or aminophlorizin. Poly(ethylene glycol) (PEG) chains of different length and varying end groups were used as tether. Experiments were performed at 10, 25 and 37 °C to address different conformational states of SGLT1. Unbinding forces between ligands and SGLT1 were recorded at different loading rates by changing the retraction velocity, yielding binding probability, width of energy barrier of the binding pocket, and the kinetic off rate constant of the binding reaction. With increasing temperature, width of energy barrier and average life time increased for the interaction of SGLT1 with thioglucose (coupled via acrylamide to a long PEG) but decreased for aminophlorizin binding. The former indicates that in the membrane-bound SGLT1 the pathway to sugar translocation involves several steps with different temperature sensitivity. The latter suggests that also the aglucon binding sites for transport inhibitors have specific, temperature-sensitive conformations.
Collapse
Affiliation(s)
- Isabel Neundlinger
- From the Institute for Biophysics, Johannes Kepler University of Linz, Gruberstrasse 40, 4020 Linz, Austria
| | - Theeraporn Puntheeranurak
- From the Institute for Biophysics, Johannes Kepler University of Linz, Gruberstrasse 40, 4020 Linz, Austria, Department of Biology, Faculty of Science, Mahidol University and Nanotec-MU Center of Excellence on Intelligent Materials and Systems, 272 Rama VI, Ratchathewi, Bangkok 10400, Thailand
| | - Linda Wildling
- From the Institute for Biophysics, Johannes Kepler University of Linz, Gruberstrasse 40, 4020 Linz, Austria
| | | | - Lai-Xi Wang
- Institute of Human Virology and Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland 21201, and
| | - Hermann J Gruber
- From the Institute for Biophysics, Johannes Kepler University of Linz, Gruberstrasse 40, 4020 Linz, Austria
| | - Rolf K H Kinne
- Max Planck Institute of Molecular Physiology, Otto-Hahn Strasse 11, 44227 Dortmund, Germany
| | - Peter Hinterdorfer
- From the Institute for Biophysics, Johannes Kepler University of Linz, Gruberstrasse 40, 4020 Linz, Austria,
| |
Collapse
|
4
|
The potassium channel KcsA: a model protein in studying membrane protein oligomerization and stability of oligomeric assembly? Arch Biochem Biophys 2011; 510:1-10. [PMID: 21458409 DOI: 10.1016/j.abb.2011.03.010] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2010] [Revised: 03/25/2011] [Accepted: 03/25/2011] [Indexed: 01/01/2023]
Abstract
Many membrane proteins are functional as stable oligomers. An understanding of the conditions that elicit and enhance oligomerization is important in many therapeutics. In this regard, protein-protein and protein-lipid interactions play crucial roles in the assembly and stability of oligomeric complexes. Recent years have seen a rapid increase in the mechanistic information on the importance of cytoplasmic termini in determining subunit assembly and stability of oligomeric complexes. In addition, the role of specific protein-lipid interaction between anionic phospholipids and "hot spots" on the protein surface has also become evident in stabilizing oligomeric assemblies. This review focuses on several contemporary developments of membrane proteins that stabilize oligomers by taking the potassium channel KcsA as an exemplary ion channel.
Collapse
|
5
|
Tyagi NK, Puntheeranurak T, Raja M, Kumar A, Wimmer B, Neundlinger I, Gruber H, Hinterdorfer P, Kinne RK. A biophysical glance at the outer surface of the membrane transporter SGLT1. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1808:1-18. [DOI: 10.1016/j.bbamem.2010.07.028] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2010] [Revised: 07/22/2010] [Accepted: 07/26/2010] [Indexed: 10/19/2022]
|
6
|
Bunge A, Windeck AK, Pomorski T, Schiller J, Herrmann A, Huster D, Müller P. Biophysical characterization of a new phospholipid analogue with a spin-labeled unsaturated fatty acyl chain. Biophys J 2009; 96:1008-15. [PMID: 19186138 DOI: 10.1016/j.bpj.2008.10.037] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2008] [Accepted: 10/21/2008] [Indexed: 11/27/2022] Open
Abstract
Spin-labeled analogs of phospholipids have been used widely to characterize the biophysical properties of membranes. We describe synthesis and application of a new spin-labeled phospholipid analog, SL-POPC. The advantage of this molecule is that the EPR active doxyl group is linked to an unsaturated fatty acyl chain different to saturated phospholipid analogs used so far. The need for those analogs arises from the fact that biological membranes contain unsaturated phospholipids to a large extent. The biophysical properties of SL-POPC in membranes were characterized using EPR and NMR spectroscopy and compared with those of the saturated spin-labeled phospholipid, SL-PSPC. To this end, POPC membranes were labeled with either analog to assess whether the spin-labeled counterpart SL-POPC mimics the membrane properties better than the often used SL-PSPC. The results show that SL-POPC and SL-PSPC explore different molecular environments of the bilayer, and that the type and degree of perturbation of bilayer caused by the label moiety also differs between both analogs. We found that SL-POPC is more appropriate to assess the versatile dynamics of POPC membranes than SL-PSPC.
Collapse
Affiliation(s)
- Andreas Bunge
- Institute of Medical Physics and Biophysics, University of Leipzig, Leipzig, Germany
| | | | | | | | | | | | | |
Collapse
|
7
|
Wimmer B, Raja M, Hinterdorfer P, Gruber HJ, Kinne RKH. C-terminal Loop 13 of Na+/Glucose Cotransporter 1 Contains Both Stereospecific and Non-stereospecific Sugar Interaction Sites. J Biol Chem 2009; 284:983-91. [DOI: 10.1074/jbc.m805082200] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
|
8
|
Kumar A, Tyagi NK, Arevalo E, Miller KW, Kinne RKH. A proteomic study of sodium/d-glucose cotransporter 1 (SGLT1): Topology of loop 13 and coverage of other functionally important domains. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2007; 1774:968-74. [PMID: 17588833 DOI: 10.1016/j.bbapap.2007.05.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2006] [Revised: 05/04/2007] [Accepted: 05/08/2007] [Indexed: 11/16/2022]
Abstract
In order to obtain further information about the structure and function of human sodium/D-glucose cotransporter 1 (hSGLT1), the recombinant protein was subjected, either after reconstitution into liposomes or in its free form, to proteolysis followed by nanoscale microcapillary liquid chromatography electrospray ionization tandem mass spectrometry (LC-MS/MS). The peptides released from SGLT1 proteoliposomes by trypsin bead digestion represented the early N-terminal, loop 7, and loop 9, supporting topology models that place these domains on the extracellular side of the protein. Trypsin bead digestion generated, however, also a number of peptides derived from loop 13 whose topology with regard to the membrane is hitherto a point of debate. Sequence coverage was provided from amino acids 559 to 644, suggesting that loop 13 is almost completely accessible at the extravesicular face of the proteoliposomes. These results support the notion that major parts of loop 13, essential for the interaction with transport inhibitors in vivo, are located extracellularly in intact cells. In-gel trypsin, chymotrypsin, and in particular trypsin/chymotrypsin digestion of recombinant SGLT1 in combination with LC-MS/MS provide extensive sequence coverage of the protein, including domains involved in sugar and inhibitor binding and potential phosphorylation sites. These studies demonstrate that proteomic analysis combined with mass spectrometry is a useful tool to characterize regions of SGLT1 that are important for its function and regulation.
Collapse
Affiliation(s)
- Azad Kumar
- Max Planck Institute of Molecular Physiology, Otto-Hahn-Str. 11, Dortmund 44227, Germany
| | | | | | | | | |
Collapse
|
9
|
Puntheeranurak T, Kasch M, Xia X, Hinterdorfer P, Kinne RKH. Three surface subdomains form the vestibule of the Na+/glucose cotransporter SGLT1. J Biol Chem 2007; 282:25222-30. [PMID: 17616521 DOI: 10.1074/jbc.m704190200] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A combination of biophysical and biochemical approaches was employed to probe the topology, arrangement, and function of the large surface subdomains of SGLT1 in living cells. Using atomic force microscopy on the single molecule level, Chinese hamster ovary cells overexpressing SGLT1 were probed with atomic force microscopy tips carrying antibodies against epitopes of different subdomains. Specific single molecule recognition events were observed with antibodies against loop 6-7, loop 8-9, and loop 13-14, demonstrating the extracellular orientation of these subdomains. The addition of D-glucose in Na+-containing medium decreased the binding probability of the loop 8-9 antibody, suggesting a transport-related conformational change in the region between amino acids 339 and 356. Transport studies with mutants C345A, C351A, C355A, or C361S supported a role for these amino acids in determining the affinity of SGLT1 for D-glucose. MTSET, [2-(trimethylammonium)ethyl] methanethiosulfonate and dithiothreitol inhibition patterns on alpha-methyl-glucoside uptake by COS-7 cells expressing C255A, C560A, or C608A suggested the presence of a disulfide bridge between Cys255 and Cys608. This assumption was corroborated by matrix-assisted laser desorption ionization time-of-flight mass spectrometry showing mass differences in peptides derived from transporters biotinylated in the absence and presence of dithiothreitol. These results indicate that loop 6-7 and loop 13-14 are connected by a disulfide bridge. This bridge brings also loop 8-9 into close vicinity with the former subdomains to create a vestibule for sugar binding.
Collapse
Affiliation(s)
- Theeraporn Puntheeranurak
- Department of Biology, Faculty of Science, Mahidol University, and Center of Excellence, National Nanotechnology Center at Mahidol University, Bangkok, 10400, Thailand
| | | | | | | | | |
Collapse
|