1
|
Bresson S, Shchepachev V, Tollervey D. A posttranscriptional pathway regulates cell wall mRNA expression in budding yeast. Cell Rep 2023; 42:112184. [PMID: 36862555 DOI: 10.1016/j.celrep.2023.112184] [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: 09/30/2022] [Revised: 01/05/2023] [Accepted: 02/14/2023] [Indexed: 03/03/2023] Open
Abstract
The fungal cell wall provides protection and structure and is an important target for antifungal compounds. A mitogen-activated protein (MAP) kinase cascade termed the cell wall integrity (CWI) pathway regulates transcriptional responses to cell wall damage. Here, we describe a posttranscriptional pathway that plays an important complementary role. We report that the RNA-binding proteins (RBPs) Mrn1 and Nab6 specifically target the 3' UTRs of a largely overlapping set of cell wall-related mRNAs. These mRNAs are downregulated in the absence of Nab6, indicating a function in target mRNA stabilization. Nab6 acts in parallel to CWI signaling to maintain appropriate expression of cell wall genes during stress. Cells lacking both pathways are hypersensitive to antifungal compounds targeting the cell wall. Deletion of MRN1 partially alleviates growth defects associated with Δnab6, and Mrn1 has an opposing function in mRNA destabilization. Our results uncover a posttranscriptional pathway that mediates cellular resistance to antifungal compounds.
Collapse
Affiliation(s)
- Stefan Bresson
- Wellcome Centre for Cell Biology and Institute of Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, Scotland, UK.
| | - Vadim Shchepachev
- Wellcome Centre for Cell Biology and Institute of Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, Scotland, UK
| | - David Tollervey
- Wellcome Centre for Cell Biology and Institute of Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, Scotland, UK.
| |
Collapse
|
2
|
Tohumeken S, Deme P, Yoo SW, Gupta S, Rais R, Slusher BS, Haughey NJ. Neuronal deletion of nSMase2 reduces the production of Aβ and directly protects neurons. Neurobiol Dis 2023; 177:105987. [PMID: 36603748 DOI: 10.1016/j.nbd.2023.105987] [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: 07/22/2022] [Revised: 12/28/2022] [Accepted: 01/01/2023] [Indexed: 01/03/2023] Open
Abstract
Extracellular vesicles (EVs) have been proposed to regulate the deposition of Aβ. Multiple publications have shown that APP, amyloid processing enzymes and Aβ peptides are associated with EVs. However, very little Aβ is associated with EVs compared with the total amount Aβ present in human plasma, CSF, or supernatants from cultured neurons. The involvement of EVs has largely been inferred by pharmacological inhibition or whole body deletion of the sphingomyelin hydrolase neutral sphingomyelinase-2 (nSMase2) that is a key regulator for the biogenesis of at-least one population of EVs. Here we used a Cre-Lox system to selectively delete nSMase2 from pyramidal neurons in APP/PS1 mice (APP/PS1-SMPD3-Nex1) and found a ∼ 70% reduction in Aβ deposition at 6 months of age and ∼ 35% reduction at 12 months of age in both cortex and hippocampus. Brain ceramides were increased in APP/PS1 compared with Wt mice, but were similar to Wt in APP/PS1-SMPD3-Nex1 mice suggesting that elevated brain ceramides in this model involves neuronally expressed nSMase2. Reduced levels of PSD95 and deficits of long-term potentiation in APP/PS1 mice were normalized in APP/PS1-SMPD3-Nex1 mice. In contrast, elevated levels of IL-1β, IL-8 and TNFα in APP/PS1 mice were not normalized in APP/PS1-SMPD3-Nex1 mice compared with APP/PS1 mice. Mechanistic studies showed that the size of liquid ordered membrane microdomains was increased in APP/PS1 mice, as were the amounts of APP and BACE1 localized to these microdomains. Pharmacological inhibition of nSMase2 activity with PDDC reduced the size of the liquid ordered membrane microdomains, reduced the localization of APP with BACE1 and reduced the production of Aβ1-40 and Aβ1-42. Although inhibition of nSMase2 reduced the release and increased the size of EVs, very little Aβ was associated with EVs in all conditions tested. We also found that nSMase2 directly protected neurons from the toxic effects of oligomerized Aβ and preserved neural network connectivity despite considerable Aβ deposition. These data demonstrate that nSMase2 plays a role in the production of Aβ by stabilizing the interaction of APP with BACE1 in liquid ordered membrane microdomains, and directly protects neurons from the toxic effects of Aβ. The effects of inhibiting nSMase2 on EV biogenesis may be independent from effects on Aβ production and neuronal protection.
Collapse
Affiliation(s)
- Sehmus Tohumeken
- The Johns Hopkins University School of Medicine, Departments of Neurology, United States of America
| | - Pragney Deme
- The Johns Hopkins University School of Medicine, Departments of Neurology, United States of America
| | - Seung Wan Yoo
- The Johns Hopkins University School of Medicine, Departments of Neurology, United States of America
| | - Sujasha Gupta
- The Johns Hopkins University School of Medicine, Departments of Neurology, United States of America
| | - Rana Rais
- The Johns Hopkins University School of Medicine, Departments of Psychiatry, United States of America
| | - Barbara S Slusher
- The Johns Hopkins University School of Medicine, Departments of Neurology, United States of America; The Johns Hopkins University School of Medicine, Departments of Johns Hopkins Drug Discovery, United States of America; The Johns Hopkins University School of Medicine, Departments of Psychiatry, United States of America; The Johns Hopkins University School of Medicine, Departments of Pharmacology and Molecular Sciences, United States of America; The Johns Hopkins University School of Medicine, Departments of Department of Oncology, United States of America; The Johns Hopkins University School of Medicine, Departments of Department of Neuroscience, United States of America; The Johns Hopkins University School of Medicine, Departments of Department of Medicine, Baltimore, MD, United States of America
| | - Norman J Haughey
- The Johns Hopkins University School of Medicine, Departments of Neurology, United States of America; The Johns Hopkins University School of Medicine, Departments of Johns Hopkins Drug Discovery, United States of America.
| |
Collapse
|
3
|
Gerstmeier J, Newcomer ME, Dennhardt S, Romp E, Fischer J, Werz O, Garscha U. 5-Lipoxygenase-activating protein rescues activity of 5-lipoxygenase mutations that delay nuclear membrane association and disrupt product formation. FASEB J 2016; 30:1892-900. [PMID: 26842853 DOI: 10.1096/fj.201500210r] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Accepted: 01/17/2016] [Indexed: 12/26/2022]
Abstract
Leukotrienes (LTs) are proinflammatory lipid mediators formed from arachidonic acid in a 2-step reaction catalyzed by 5-lipoxygenase (5-LOX) requiring the formation of 5-HPETE [5(S)-hydroperoxy-6-trans-8,11,14-cis-eicosatetraenoic acid] and its subsequent transformation to LTA4 5-LOX is thought to receive arachidonic acid from the nuclear membrane-embedded 5-LOX-activating protein (FLAP). The crystal structure of 5-LOX revealed an active site concealed by F177 and Y181 (FY cork). We examined the influence of the FY cork on 5-LOX activity and membrane binding in HEK293 cells in the absence and presence of FLAP. Uncapping the 5-LOX active site by mutation of F177 and/or Y181 to alanine (5-LOX-F177A, 5-LOX-Y181A, 5-LOX-F177/Y181A) resulted in delayed and diminished 5-LOX membrane association in A23187-stimulated cells. For 5-LOX-F177A and 5-LOX-F177/Y181A, formation of 5-LOX products was dramatically reduced relative to 5-LOX-wild type (wt). Strikingly, coexpression of FLAP in A23187-activated HEK293 cells effectively restored formation of 5-H(p)ETE (5-hydroxy- and 5-peroxy-6-trans-8,11,14-cis-eicosatetraenoic acid) by these same 5-LOX mutants (≈60-70% 5-LOX-wt levels) but not of LTA4 hydrolysis products. Yet 5-LOX-Y181A generated 5-H(p)ETE at levels comparable to 5-LOX-wt but reduced LTA4 hydrolysis products. Coexpression of FLAP partially restored LTA4 hydrolysis product formation by 5-LOX-Y181A. Together, the data suggest that the concealed FY cork impacts membrane association and that FLAP may help shield an uncapped active site.-Gerstmeier, J., Newcomer, M. E., Dennhardt, S., Romp, E., Fischer, J., Werz, O., Garscha, U. 5-Lipoxygenase-activating protein rescues activity of 5-lipoxygenase mutations that delay nuclear membrane association and disrupt product formation.
Collapse
Affiliation(s)
- Jana Gerstmeier
- Department of Pharmaceutical and Medicinal Chemistry, Institute of Pharmacy, Friedrich-Schiller-University Jena, Germany; and
| | - Marcia E Newcomer
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana, USA
| | - Sophie Dennhardt
- Department of Pharmaceutical and Medicinal Chemistry, Institute of Pharmacy, Friedrich-Schiller-University Jena, Germany; and
| | - Erik Romp
- Department of Pharmaceutical and Medicinal Chemistry, Institute of Pharmacy, Friedrich-Schiller-University Jena, Germany; and
| | - Jana Fischer
- Department of Pharmaceutical and Medicinal Chemistry, Institute of Pharmacy, Friedrich-Schiller-University Jena, Germany; and
| | - Oliver Werz
- Department of Pharmaceutical and Medicinal Chemistry, Institute of Pharmacy, Friedrich-Schiller-University Jena, Germany; and
| | - Ulrike Garscha
- Department of Pharmaceutical and Medicinal Chemistry, Institute of Pharmacy, Friedrich-Schiller-University Jena, Germany; and
| |
Collapse
|
4
|
Abel S, Lorieau A, de Foresta B, Dupradeau FY, Marchi M. Bindings of hMRP1 transmembrane peptides with dodecylphosphocholine and dodecyl-β-d-maltoside micelles: a molecular dynamics simulation study. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1838:493-509. [PMID: 24157718 DOI: 10.1016/j.bbamem.2013.10.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2013] [Revised: 09/17/2013] [Accepted: 10/14/2013] [Indexed: 12/24/2022]
Abstract
In this paper, we describe molecular dynamics simulation results of the interactions between four peptides (mTM10, mTM16, TM17 and KTM17) with micelles of dodecylphosphocholine (DPC) and dodecyl-β-d-maltoside (DDM). These peptides represent three transmembrane fragments (TM10, 16 and 17) from the MSD1 and MSD2 membrane-spanning domains of an ABC membrane protein (hMRP1), which play roles in the protein functions. The peptide-micelle complex structures, including the tryptophan accessibility and dynamics were compared to circular dichroism and fluorescence studies obtained in water, trifluoroethanol and with micelles. Our work provides additional results not directly accessible by experiments that give further support to the fact that these peptides adopt an interfacial conformation within the micelles. We also show that the peptides are more buried in DDM than in DPC, and consequently, that they have a larger surface exposure to water in DPC than in DDM. As noted previously by simulations and experiments we have also observed formation of cation-π bonds between the phosphocholine DPC headgroup and Trp peptide residue. Concerning the peptide secondary structures (SS), we find that in TFE their initial helical conformations are maintained during the simulation, whereas in water their initial SS are lost after few nanoseconds of simulation. An intermediate situation is observed with micelles, where the peptides remain partially folded and more structured in DDM than in DPC. Finally, our results show no sign of β-strand structure formation as invoked by far-UV CD experiments even when three identical peptides are simulated either in water or with micelles.
Collapse
Affiliation(s)
- Stéphane Abel
- Commissariat à l'Energie Atomique et aux Energies Alternatives, DSV/iBiTEC-S/SB2SM/LBMS & CNRS UMR 8221, Saclay, France.
| | | | | | | | | |
Collapse
|
5
|
Deshayes S, Divita G. Fluorescence technologies for monitoring interactions between biological molecules in vitro. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2013; 113:109-43. [PMID: 23244790 DOI: 10.1016/b978-0-12-386932-6.00004-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Over the last two centuries, the discovery and understanding of the principle of fluorescence have provided new means of characterizing physical/biological/chemical processes in a noninvasive manner. Fluorescence spectroscopy has become one of the most powerful and widely applied methods in the life sciences, from fundamental research to clinical applications. In vitro, fluorescence approaches offer the potential to sense in real-time extra and intracellular molecular interactions and enzymatic reactions, which constitutes a major advantage over other approaches to the study of biomolecular interactions. This technology has been used for the characterization of protein/protein, protein/nucleic acid, protein/substrate, and biomembrane/biomolecule interactions, which play crucial roles in the regulation of cellular pathways. This chapter reviews the different fluorescence strategies that have been developed for sensing molecular interactions in vitro at both steady- and pre-steady-state levels.
Collapse
Affiliation(s)
- Sebastien Deshayes
- Centre de Recherches de Biochimie Macromoléculaire, Department of Chemical Biology and Nanotechnology for Therapeutics, CRBM-CNRS, UMR-5237, UM1-UM2, University of Montpellier, 1919 Route de Mende, Montpellier, France
| | | |
Collapse
|
6
|
Aoki S, Epand RM. Caveolin-1 hydrophobic segment peptides insertion into membrane mimetic systems: Role of Proline residue. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1818:12-8. [DOI: 10.1016/j.bbamem.2011.09.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2011] [Revised: 09/08/2011] [Accepted: 09/11/2011] [Indexed: 11/28/2022]
|
7
|
Khao J, Arce-Lopera J, Sturgis JN, Duneau JP. Structure of a protein-detergent complex: the balance between detergent cohesion and binding. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2011; 40:1143-55. [PMID: 21901295 DOI: 10.1007/s00249-011-0745-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2011] [Accepted: 08/10/2011] [Indexed: 10/17/2022]
Abstract
Despite the major interest in membrane proteins at functional, genomic, and therapeutic levels, their biochemical and structural study remains challenging, as they require, among other things, solubilization in detergent micelles. The complexity of this task derives from the dependence of membrane protein structure on their anisotropic environment, influenced by a delicate balance between many different physicochemical properties. To study such properties in a small protein-detergent complex, we used fluorescence measurements and molecular dynamics (MD) simulations on the transmembrane part of glycophorin A (GpAtm) solubilized in micelles of dihexanoylphosphatidylcholine (DHPC) detergent. Fluorescence measurements show that DHPC has limited ability to solubilize the peptide, while MD provides a possible molecular explanation for this. We observe that the detergent molecules are balanced between two different types of interactions: cohesive interactions between detergent molecules that hold the micelle together, and adhesive interactions with the peptide. While the cohesive interactions are detergent mediated, the adhesion to the peptide depends on the specific interactions between the hydrophobic parts of the detergent and the topography of the peptide dictated by the amino acids. The balance between these two parameters results in a certain frustration of the system and rather slow equilibration. These observations suggest how molecular properties of detergents could influence membrane protein stabilization and solubilization.
Collapse
Affiliation(s)
- Jonathan Khao
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires, CNRS-Aix Marseille Université, France
| | | | | | | |
Collapse
|
8
|
Abstract
Integral membrane proteins of the cell surface and most intracellular compartments of eukaryotic cells are assembled at the endoplasmic reticulum. Two highly conserved and parallel pathways mediate membrane protein targeting to and insertion into this organelle. The classical cotranslational pathway, utilized by most membrane proteins, involves targeting by the signal recognition particle followed by insertion via the Sec61 translocon. A more specialized posttranslational pathway, employed by many tail-anchored membrane proteins, is composed of entirely different factors centered around a cytosolic ATPase termed TRC40 or Get3. Both of these pathways overcome the same biophysical challenges of ferrying hydrophobic cargo through an aqueous milieu, selectively delivering it to one among several intracellular membranes and asymmetrically integrating its transmembrane domain(s) into the lipid bilayer. Here, we review the conceptual and mechanistic themes underlying these core membrane protein insertion pathways, the complexities that challenge our understanding, and future directions to overcome these obstacles.
Collapse
Affiliation(s)
- Sichen Shao
- Cell Biology and Metabolism Program, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
| | | |
Collapse
|
9
|
Beswick V, Isvoran A, Nédellec P, Sanson A, Jamin N. Membrane interface composition drives the structure and the tilt of the single transmembrane helix protein PMP1: MD studies. Biophys J 2011; 100:1660-7. [PMID: 21463579 DOI: 10.1016/j.bpj.2011.02.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2010] [Revised: 02/01/2011] [Accepted: 02/02/2011] [Indexed: 11/16/2022] Open
Abstract
PMP1, a regulatory subunit of the yeast plasma membrane H(+)-ATPase, is a single transmembrane helix protein. Its cytoplasmic C-terminus possesses several positively charged residues and interacts with phosphatidylserine lipids as shown through both (1)H- and (2)H-NMR experiments. We used all-atom molecular dynamics simulations to obtain atomic-scale data on the effects of membrane interface lipid composition on PMP1 structure and tilt. PMP1 was embedded in two hydrated bilayers, differing in the composition of the interfacial region. The neutral bilayer is composed of POPC (1-palmitoyl-2-oleoyl-3-glycero-phosphatidylcholine) lipids and the negatively charged bilayer is composed of POPC and anionic POPS (1-palmitoyl-2-oleoyl-3-glycero-phosphatidylserine) lipids. Our results were consistent with NMR data obtained previously, such as a lipid sn-2 chain lying on the W28 aromatic ring and in the groove formed on one side of the PMP1 helix. In pure POPC, the transmembrane helix is two residues longer than the initial structure and the helix tilt remains constant at 6 ± 3°. By contrast, in mixed POPC-POPS, the initial helical structure of PMP1 is stable throughout the simulation time even though the C-terminal residues interact strongly with POPS headgroups, leading to a significant increase of the helix tilt within the membrane to 20 ± 5°.
Collapse
Affiliation(s)
- Veronica Beswick
- Commissariat à l'Énergie Atomique (CEA), Institute of Biology and Technology (iBiTecS), Gif-sur-Yvette, France.
| | | | | | | | | |
Collapse
|
10
|
de Foresta B, Vincent M, Garrigos M, Gallay J. Transverse and tangential orientation of predicted transmembrane fragments 4 and 10 from the human multidrug resistance protein (hMRP1/ABCC1) in membrane mimics. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2011; 40:1043-60. [DOI: 10.1007/s00249-011-0721-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2011] [Revised: 05/23/2011] [Accepted: 06/01/2011] [Indexed: 01/29/2023]
|
11
|
de Foresta B, Vincent M, Gallay J, Garrigos M. Interaction with membrane mimics of transmembrane fragments 16 and 17 from the human multidrug resistance ABC transporter 1 (hMRP1/ABCC1) and two of their tryptophan variants. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2010; 1798:401-14. [DOI: 10.1016/j.bbamem.2009.11.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2009] [Revised: 11/12/2009] [Accepted: 11/30/2009] [Indexed: 10/20/2022]
|
12
|
Bordag N, Keller S. α-Helical transmembrane peptides: A “Divide and Conquer” approach to membrane proteins. Chem Phys Lipids 2010; 163:1-26. [PMID: 19682979 DOI: 10.1016/j.chemphyslip.2009.07.009] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2009] [Revised: 07/21/2009] [Accepted: 07/21/2009] [Indexed: 11/26/2022]
|
13
|
Coïc YM, Lan CL, Neumann JM, Jamin N, Baleux F. Slightly modifying pseudoproline dipeptides incorporation strategy enables solid phase synthesis of a 54 AA fragment of caveolin-1 encompassing the intramembrane domain. J Pept Sci 2009; 16:98-104. [DOI: 10.1002/psc.1203] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
|
14
|
Bouhss A, Al-Dabbagh B, Vincent M, Odaert B, Aumont-Nicaise M, Bressolier P, Desmadril M, Mengin-Lecreulx D, Urdaci MC, Gallay J. Specific interactions of clausin, a new lantibiotic, with lipid precursors of the bacterial cell wall. Biophys J 2009; 97:1390-7. [PMID: 19720027 DOI: 10.1016/j.bpj.2009.06.029] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2009] [Revised: 06/23/2009] [Accepted: 06/24/2009] [Indexed: 11/28/2022] Open
Abstract
We investigated the specificity of interaction of a new type A lantibiotic, clausin, isolated from Bacillus clausii, with lipid intermediates of bacterial envelope biosynthesis pathways. Isothermal calorimetry and steady-state fluorescence anisotropy (with dansylated derivatives) identified peptidoglycan lipids I and II, embedded in dodecylphosphocholine micelles, as potential targets. Complex formation with dissociation constants of approximately 0.3 muM and stoichiometry of approximately 2:1 peptides/lipid intermediate was observed. The interaction is enthalpy-driven. For the first time, to our knowledge, we evidenced the interaction between a lantibiotic and C(55)-PP-GlcNAc, a lipid intermediate in the biosynthesis of other bacterial cell wall polymers, including teichoic acids. The pyrophosphate moiety of these lipid intermediates was crucial for the interaction because a strong binding with undecaprenyl pyrophosphate, accounting for 80% of the free energy of binding, was observed. No binding occurred with the undecaprenyl phosphate derivative. The pentapeptide and the N-acetylated sugar moieties strengthened the interaction, but their contributions were weaker than that of the pyrophosphate group. The lantibiotic decreased the mobility of the pentapeptide. Clausin did not interact with the water-soluble UDP-MurNAc- and pyrophosphoryl-MurNAc-pentapeptides, pointing out the importance of the hydrocarbon chain of the lipid target.
Collapse
Affiliation(s)
- Ahmed Bouhss
- CNRS, UMR 8619, Institut de Biochimie et Biophysique Moléculaire et Cellulaire, Orsay, France.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
15
|
Structural and dynamic properties of juxta-membrane segments of caveolin-1 and caveolin-2 at the membrane interface. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2009; 39:307-25. [PMID: 19847421 DOI: 10.1007/s00249-009-0548-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2009] [Revised: 09/15/2009] [Accepted: 09/24/2009] [Indexed: 12/21/2022]
Abstract
Caveolins (cav1-3) are essential membrane proteins found in caveolae. The caveolin scaffolding domain of cav-1 includes a short sequence containing a CRAC motif (V94TKYWFYR101) at its C-terminal end. To investigate the role of this motif in the caveolin-membrane interaction at the atomic level, we performed a detailed structural and dynamics characterization of a cav-1(V94-L102) nonapeptide encompassing this motif and including the first residue of cav-1 hydrophobic domain (L102), in dodecylmaltoside (DM) or dodecylphosphocholine (DPC) micelles, as membrane mimics. Cav-1(V94-L102) partitioned better in DPC and in DM/anionic lipid micelles than in DM micelles, as shown by fluorescence titration and CD. NMR data revealed that this peptide folded as an amphipathic helix located in the polar head group region of DPC micelles. The two tyrosine side-chains, flanked by arginine and lysine residues, are situated on one face of this helix, whereas the phenylalanine and tryptophan side-chains are located on the opposite face. Fluorescence studies showed significant Trp subnanosecond rotations, the presence of several rotamers, and a heterogeneous location within the water/micelle interface. NMR studies of the shorter cav-1(V94-R101) peptide and of the homologous sequence of cav-2(I79SKYVMYKF87) allowed the description of the effect of L102 and of the amino acid variations occurring in cav-2 on the structure and localization in DPC micelles. Based on the topological model of caveolins, our results suggest that the cav-1 and cav-2 nonapeptides studied form interfacial alpha-helix membrane anchors in which the K/RhhhYK/Rh motif, also found in cav-3, may play a significant role.
Collapse
|
16
|
Reis S, Moutinho CG, Pereira E, de Castro B, Gameiro P, Lima JLFC. Beta-blockers and benzodiazepines location in SDS and bile salt micellar systems. An ESR study. J Pharm Biomed Anal 2007; 45:62-69. [PMID: 17606356 DOI: 10.1016/j.jpba.2007.05.023] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2007] [Revised: 05/18/2007] [Accepted: 05/21/2007] [Indexed: 10/23/2022]
Abstract
The work here described aimed to find out the location of the different species of two families of pharmaceutical substances, namely two beta-blockers (atenolol and nadolol) and two benzodiazepines (midazolam and nitrazepam) in synthetic (sodium dodecyl sulphate, SDS) and natural (bile salts-sodium cholate and sodium deoxycholate) micellar aggregate solutions. Electronic spin resonance spectroscopy studies were carried out, at 25 degrees C and at an ionic strength of 0.10 M in NaCl, using 5-, 12- and 16-doxylstearic acid probes (AS). The immobilization degree of solubilized stearic acid spin probes was found to vary with the position of the nitroxide group in the sequence 5-doxylstearic acid>12-doxylstearic acid>16-doxylstearic acid for SDS and 12-doxylstearic acid>5-doxylstearic acid>16-doxylstearic acid for both bile salts investigated. Therefore, from the rotational correlational time values obtained, it can be inferred that the structure of bile salt micelles is markedly different from that of SDS micelles and the results suggest that the bile salt micelles studied have similar structure independently of differences in the molecular structure of the respective bile salts. Drug location studies were performed at pH 4.0 (SDS solutions) or 7.0 (bile salt solutions) and 10.8 in order to study the effect of the drug ionisation on its relative position on micelles. The results have shown that drug location is controlled by the (i) drug hydrophilicity and acid/base properties, with the more soluble compound in water (atenolol) exhibiting smaller variation of rotational correlational time (in SDS and bile salts solutions), and with both beta-blockers exhibiting smaller deviations in the protonated forms and (ii) the bile salt monomers, with the dihydroxylic bile salt (deoxycholate) producing larger differences. The work described herein allow us to conclude that the (protonated) beta-blockers are probably located on the surface of the detergent micelles, and linked to them by means of essentially electrostatic forces, while the (neutral) benzodiazepines are probably located deeper in the interior of the micelles.
Collapse
Affiliation(s)
- Salette Reis
- REQUIMTE, Departamento de Química-Física, Faculdade de Farmácia, Universidade do Porto, 4099-030 Porto, Portugal.
| | | | - Eulália Pereira
- REQUIMTE, Departamento de Química, Faculdade de Ciências, Universidade do Porto, 4169-007 Porto, Portugal
| | - Baltazar de Castro
- REQUIMTE, Departamento de Química, Faculdade de Ciências, Universidade do Porto, 4169-007 Porto, Portugal
| | - Paula Gameiro
- REQUIMTE, Departamento de Química, Faculdade de Ciências, Universidade do Porto, 4169-007 Porto, Portugal
| | - José L F C Lima
- REQUIMTE, Departamento de Química-Física, Faculdade de Farmácia, Universidade do Porto, 4099-030 Porto, Portugal
| |
Collapse
|
17
|
Vincent M, Gallay J, Jamin N, Garrigos M, de Foresta B. The predicted transmembrane fragment 17 of the human multidrug resistance protein 1 (MRP1) behaves as an interfacial helix in membrane mimics. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2006; 1768:538-52. [PMID: 17257580 DOI: 10.1016/j.bbamem.2006.11.021] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2006] [Revised: 11/09/2006] [Accepted: 11/29/2006] [Indexed: 11/15/2022]
Abstract
The human multidrug resistance protein MRP1 (or ABCC1) is one of the most important members of the large ABC transporter family, in terms of both its biological (tissue defense) and pharmacological functions. Many studies have investigated the function of MRP1, but structural data remain scarce for this protein. We investigated the structure and dynamics of predicted transmembrane fragment 17 (TM17, from Ala(1227) to Ser(1251)), which contains a single Trp residue (W(1246)) involved in MRP1 substrate specificity and transport function. We synthesized TM17 and a modified peptide in which Ala(1227) was replaced by a charged Lys residue. Both peptides were readily solubilized in dodecylmaltoside (DM) or dodecylphosphocholine (DPC) micelles, as membrane mimics. The interaction of these peptides with DM or DPC micelles was studied by steady-state and time-resolved Trp fluorescence spectroscopy, including experiments in which Trp was quenched by acrylamide or by two brominated analogs of DM. The secondary structure of these peptides was determined by circular dichroism. Overall, the results obtained indicated significant structuring ( approximately 50% alpha-helix) of TM17 in the presence of either DM or DPC micelles as compared to buffer. A main interfacial location of TM17 is proposed, based on significant accessibility of Trp(1246) to brominated alkyl chains of DM and/or acrylamide. The comparison of various fluorescence parameters including lambda(max), lifetime distributions and Trp rotational mobility with those determined for model fluorescent transmembrane helices in the same detergents is also consistent with the interfacial location of TM17. We therefore suggest that TM17 intrinsic properties may be insufficient for its transmembrane insertion as proposed by the MRP1 consensus topological model. This insertion may also be controlled by additional constraints such as interactions with other TM domains and its position in the protein sequence. The particular pattern of behavior of this predicted transmembrane peptide may be the hallmark of a fragment involved in substrate transport.
Collapse
Affiliation(s)
- Michel Vincent
- CNRS UMR8619 IBBMC, Orsay, F-91405, France; Univ Paris-Sud, Orsay, F-91405, France
| | | | | | | | | |
Collapse
|