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Paratore TA, Schmidt GE, Ross AH, Gericke A. Thermal stability of bivalent cation/phosphoinositide domains in model membranes. Chem Phys Lipids 2024; 264:105424. [PMID: 39098579 DOI: 10.1016/j.chemphyslip.2024.105424] [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: 06/19/2024] [Revised: 07/30/2024] [Accepted: 07/31/2024] [Indexed: 08/06/2024]
Abstract
As key mediators in a wide array of signaling events, phosphoinositides (PIPs) orchestrate the recruitment of proteins to specific cellular locations at precise moments. This intricate spatiotemporal regulation of protein activity often necessitates the localized enrichment of the corresponding PIP. We investigate the extent and thermal stabilities of phosphatidylinositol-4-phosphate (PI(4)P), phosphatidylinositol-4,5-bisphosphate (PI(4,5)P2 and phosphatidylinositol-3,4,5-trisphosphate (PI(3,4,5)P3) clusters with calcium and magnesium ions. We observe negligible or minimal clustering of all examined PIPs in the presence of Mg2+ ions. While PI(4)P shows in the presence of Ca2+ no clustering, PI(4,5)P2 forms with Ca2+ strong clusters that exhibit stablity up to at least 80°C. The extent of cluster formation for the interaction of PI(3,4,5)P3 with Ca2+ is less than what was observed for PI(4,5)P2, yet we still observe some clustering up to 80°C. Given that cholesterol has been demonstrated to enhance PIP clustering, we examined whether bivalent cations and cholesterol synergistically promote PIP clustering. We found that the interaction of Mg2+ or Ca2+ with PI(4)P remains extraordinarily weak, even in the presence of cholesterol. In contrast, we observe synergistic interaction of cholesterol and Ca2+ with PI(4,5)P2. Also, in the presence of cholesterol, the interaction of Mg2+ with PI(4,5)P2 remains weak. PI(3,4,5)P3 does not show strong clustering with cholesterol for the experimental conditions of our study and the interaction with Ca2+ and Mg2+ was not influenced by the presence of cholesterol.
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Affiliation(s)
- Trevor A Paratore
- Worcester Polytechnic Institute, Department of Chemistry and Biochemistry, Worcester, MA 01609, USA
| | - Greta E Schmidt
- Worcester Polytechnic Institute, Department of Chemistry and Biochemistry, Worcester, MA 01609, USA
| | - Alonzo H Ross
- Worcester Polytechnic Institute, Department of Chemistry and Biochemistry, Worcester, MA 01609, USA
| | - Arne Gericke
- Worcester Polytechnic Institute, Department of Chemistry and Biochemistry, Worcester, MA 01609, USA.
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2
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Harraz MM, Malla AP, Semenza ER, Shishikura M, Singh M, Hwang Y, Kang IG, Song YJ, Snowman AM, Cortés P, Karuppagounder SS, Dawson TM, Dawson VL, Snyder SH. A high-affinity cocaine binding site associated with the brain acid soluble protein 1. Proc Natl Acad Sci U S A 2022; 119:e2200545119. [PMID: 35412917 PMCID: PMC9169839 DOI: 10.1073/pnas.2200545119] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 03/01/2022] [Indexed: 12/25/2022] Open
Abstract
Cocaine exerts its stimulant effect by inhibiting dopamine (DA) reuptake, leading to increased dopamine signaling. This action is thought to reflect the binding of cocaine to the dopamine transporter (DAT) to inhibit its function. However, cocaine is a relatively weak inhibitor of DAT, and many DAT inhibitors do not share cocaine’s behavioral actions. Further, recent reports show more potent actions of the drug, implying the existence of a high-affinity receptor for cocaine. We now report high-affinity binding of cocaine associated with the brain acid soluble protein 1 (BASP1) with a dissociation constant (Kd) of 7 nM. Knocking down BASP1 in the striatum inhibits [3H]cocaine binding to striatal synaptosomes. Depleting BASP1 in the nucleus accumbens but not the dorsal striatum diminishes locomotor stimulation in mice. Our findings imply that BASP1 is a pharmacologically relevant receptor for cocaine.
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Affiliation(s)
- Maged M. Harraz
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Adarsha P. Malla
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Evan R. Semenza
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Maria Shishikura
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Manisha Singh
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Yun Hwang
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - In Guk Kang
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Young Jun Song
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Adele M. Snowman
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Pedro Cortés
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Senthilkumar S. Karuppagounder
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Ted M. Dawson
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Valina L. Dawson
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Solomon H. Snyder
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205
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3
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Abstract
Cholesterol is present within the cell nucleus, where it associates with chromatin, but to date, a direct role for cholesterol in nuclear processes has not been identified. We demonstrate that the transcriptional repressor brain acid soluble protein 1 (BASP1) directly interacts with cholesterol within the cell nucleus through a consensus cholesterol interaction motif. BASP1 recruits cholesterol to the promoter region of target genes, where it is required to mediate chromatin remodeling and transcriptional repression. Our work demonstrates that cholesterol plays a direct role in transcriptional regulation. Lipids are present within the cell nucleus, where they engage with factors involved in gene regulation. Cholesterol associates with chromatin in vivo and stimulates nucleosome packing in vitro, but its effects on specific transcriptional responses are not clear. Here, we show that the lipidated Wilms tumor 1 (WT1) transcriptional corepressor, brain acid soluble protein 1 (BASP1), interacts with cholesterol in the cell nucleus through a conserved cholesterol interaction motif. We demonstrate that BASP1 directly recruits cholesterol to the promoter region of WT1 target genes. Mutation of BASP1 to ablate its interaction with cholesterol or the treatment of cells with drugs that block cholesterol biosynthesis inhibits the transcriptional repressor function of BASP1. We find that the BASP1–cholesterol interaction is required for BASP1-dependent chromatin remodeling and the direction of transcription programs that control cell differentiation. Our study uncovers a mechanism for gene-specific targeting of cholesterol where it is required to mediate transcriptional repression.
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4
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Forsova OS, Zakharov VV. High-order oligomers of intrinsically disordered brain proteins BASP1 and GAP-43 preserve the structural disorder. FEBS J 2016; 283:1550-69. [PMID: 26918762 DOI: 10.1111/febs.13692] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Revised: 01/26/2016] [Accepted: 02/23/2016] [Indexed: 11/30/2022]
Abstract
Brain acid-soluble protein-1 (BASP1) and growth-associated protein-43 (GAP-43) are presynaptic membrane proteins participating in axon guidance, neuroregeneration and synaptic plasticity. They are presumed to sequester phosphatidylinositol-4,5-bisphosphate (PIP2 ) in lipid rafts. Previously we have shown that the proteins form heterogeneously sized oligomers in the presence of anionic phospholipids or SDS at submicellar concentration. BASP1 and GAP-43 are intrinsically disordered proteins (IDPs). In light of this, we investigated the structure of their oligomers. Using partial cross-linking of the oligomers with glutaraldehyde, the aggregation numbers of BASP1 and GAP-43 were estimated as 10-14 and 6-7 monomer subunits, respectively. The cross-linking pattern indicated that the subunits are circularly arranged. The circular dichroism (CD) spectra of the monomers were characteristic of coil-like IDPs showing unordered structure with a high population of polyproline-II conformation. The oligomerization was accompanied by a minor CD spectral change attributable to formation of a small amount of α-helix. The number of residues in the α-helical conformation was estimated as 13 in BASP1 and 18 in GAP-43. However, the overall structure of the oligomers remained disordered, indicating a high degree of 'fuzziness'. This was confirmed by measuring the hydrodynamic dimensions of the oligomers using polyacrylamide gradient gel electrophoresis and size-exclusion chromatography, and by assaying their sensitivity to proteolytic digestion. There is evidence that the observed α-helical folding occurs within the basic effector domains, which are presumably tethered together via anionic molecules of SDS or PIP2 . We conclude that BASP1 and GAP-43 oligomers preserve a mostly disordered structure, which may be of great importance for their function in PIP2 signaling pathway.
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Affiliation(s)
- Oksana S Forsova
- Molecular and Radiation Biophysics Division, B. P. Konstantinov Petersburg Nuclear Physics Institute, National Research Centre 'Kurchatov Institute', Gatchina, Russia.,Laboratory of Natural Polymers, Institute of Macromolecular Compounds, Russian Academy of Sciences, St Petersburg, Russia
| | - Vladislav V Zakharov
- Molecular and Radiation Biophysics Division, B. P. Konstantinov Petersburg Nuclear Physics Institute, National Research Centre 'Kurchatov Institute', Gatchina, Russia.,Laboratory of Natural Polymers, Institute of Macromolecular Compounds, Russian Academy of Sciences, St Petersburg, Russia.,Department of Biophysics, Institute of Physics, Nanotechnology and Telecommunications, Peter the Great St Petersburg Polytechnic University, Russia
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5
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Abstract
We report two crystal structures of the wild-type phosphatidylinositol 3-kinase α (PI3Kα) heterodimer refined to 2.9 Å and 3.4 Å resolution: the first as the free enzyme, the second in complex with the lipid substrate, diC4-PIP₂, respectively. The first structure shows key interactions of the N-terminal SH2 domain (nSH2) and iSH2 with the activation loop that suggest a mechanism by which the enzyme is inhibited in its basal state. In the second structure, the lipid substrate binds in a positively charged pocket adjacent to the ATP-binding site, bordered by the P-loop, the activation loop and the iSH2 domain. An additional lipid-binding site was identified at the interface of the ABD, iSH2 and kinase domains. The ability of PI3Kα to bind an additional PIP₂ molecule was confirmed in vitro by fluorescence quenching experiments. The crystal structures reveal key differences in the way the nSH2 domain interacts with wild-type p110α and with the oncogenic mutant p110αH1047R. Increased buried surface area and two unique salt-bridges observed only in the wild-type structure suggest tighter inhibition in the wild-type PI3Kα than in the oncogenic mutant. These differences may be partially responsible for the increased basal lipid kinase activity and increased membrane binding of the oncogenic mutant.
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6
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Jiang Z, Redfern RE, Isler Y, Ross AH, Gericke A. Cholesterol stabilizes fluid phosphoinositide domains. Chem Phys Lipids 2014; 182:52-61. [PMID: 24556334 DOI: 10.1016/j.chemphyslip.2014.02.003] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Revised: 02/06/2014] [Accepted: 02/07/2014] [Indexed: 11/19/2022]
Abstract
Local accumulation of phosphoinositides (PIPs) is an important factor for a broad range of cellular events including membrane trafficking and cell signaling. The negatively charged phosphoinositide headgroups can interact with cations or cationic proteins and this electrostatic interaction has been identified as the main phosphoinositide clustering mechanism. However, an increasing number of reports show that phosphoinositide-mediated signaling events are at least in some cases cholesterol dependent, suggesting other possible contributors to the segregation of phosphoinositides. Using fluorescence microscopy on giant unilamellar vesicles and monolayers at the air/water interface, we present data showing that cholesterol stabilizes fluid phosphoinositide-enriched phases. The interaction with cholesterol is observed for all investigated phosphoinositides (PI(4)P, PI(3,4)P2, PI(3,5)P2, PI(4,5)P2 and PI(3,4,5)P3) as well as phosphatidylinositol. We find that cholesterol is present in the phosphoinositide-enriched phase and that the resulting phase is fluid. Cholesterol derivatives modified at the hydroxyl group (cholestenone, cholesteryl ethyl ether) do not promote formation of phosphoinositide domains, suggesting an instrumental role of the cholesterol hydroxyl group in the observed cholesterol/phosphoinositide interaction. This leads to the hypothesis that cholesterol participates in an intermolecular hydrogen bond network formed among the phosphoinositide lipids. We had previously reported that the intra- and intermolecular hydrogen bond network between the phosphoinositide lipids leads to a reduction of the charge density at the phosphoinositide phosphomonoester groups (Kooijman et al., 2009). We believe that cholesterol acts as a spacer between the phosphoinositide lipids, thereby reducing the electrostatic repulsion, while participating in the hydrogen bond network, leading to its further stabilization. To illustrate the effect of phosphoinositide segregation on protein binding, we show that binding of the tumor suppressor protein PTEN to PI(5)P and PI(4,5)P2 is enhanced in the presence of cholesterol. These results provide new insights into how phosphoinositides mediate important cellular events.
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Affiliation(s)
- Zhiping Jiang
- Laboratory of Molecular Biophysics, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, United States
| | - Roberta E Redfern
- ProMedica Research Department, ProMedica Health System, Toledo, OH 43606, United States
| | - Yasmin Isler
- Academic Health Center BioRepository, ProMedica Health System, Toledo, OH 43606, United States
| | - Alonzo H Ross
- University of Massachusetts Medical School, Worcester, MA 01605, United States
| | - Arne Gericke
- Department of Chemistry and Biochemistry, Worcester Polytechnic Institute, 100 Institute Rd., Worcester, MA 01609, United States.
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7
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Khan S, Abu Jawdeh BG, Goel M, Schilling WP, Parker MD, Puchowicz MA, Yadav SP, Harris RC, El-Meanawy A, Hoshi M, Shinlapawittayatorn K, Deschênes I, Ficker E, Schelling JR. Lipotoxic disruption of NHE1 interaction with PI(4,5)P2 expedites proximal tubule apoptosis. J Clin Invest 2014; 124:1057-68. [PMID: 24531551 DOI: 10.1172/jci71863] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Accepted: 12/11/2013] [Indexed: 12/12/2022] Open
Abstract
Chronic kidney disease progression can be predicted based on the degree of tubular atrophy, which is the result of proximal tubule apoptosis. The Na+/H+ exchanger NHE1 regulates proximal tubule cell survival through interaction with phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2], but pathophysiologic triggers for NHE1 inactivation are unknown. Because glomerular injury permits proximal tubule luminal exposure and reabsorption of fatty acid/albumin complexes, we hypothesized that accumulation of amphipathic, long-chain acyl-CoA (LC-CoA) metabolites stimulates lipoapoptosis by competing with the structurally similar PI(4,5)P2 for NHE1 binding. Kidneys from mouse models of progressive, albuminuric kidney disease exhibited increased fatty acids, LC-CoAs, and caspase-2-dependent proximal tubule lipoapoptosis. LC-CoAs and the cytosolic domain of NHE1 directly interacted, with an affinity comparable to that of the PI(4,5)P2-NHE1 interaction, and competing LC-CoAs disrupted binding of the NHE1 cytosolic tail to PI(4,5)P2. Inhibition of LC-CoA catabolism reduced NHE1 activity and enhanced apoptosis, whereas inhibition of proximal tubule LC-CoA generation preserved NHE1 activity and protected against apoptosis. Our data indicate that albuminuria/lipiduria enhances lipotoxin delivery to the proximal tubule and accumulation of LC-CoAs contributes to tubular atrophy by severing the NHE1-PI(4,5)P2 interaction, thereby lowering the apoptotic threshold. Furthermore, these data suggest that NHE1 functions as a metabolic sensor for lipotoxicity.
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8
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Geist L, Zawadzka-Kazimierczuk A, Saxena S, Żerko S, Koźmiński W, Konrat R. ¹H, ¹³C and ¹⁵N resonance assignments of human BASP1. BIOMOLECULAR NMR ASSIGNMENTS 2013; 7:315-319. [PMID: 23179057 PMCID: PMC3758512 DOI: 10.1007/s12104-012-9436-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Accepted: 10/31/2012] [Indexed: 05/30/2023]
Abstract
Brain acid-soluble protein 1 (BASP1, CAP-23, NAP-22) appears to be implicated in diverse cellular processes. An N-terminally myristoylated form of BASP1 has been discovered to participate in the regulation of actin cytoskeleton dynamics in neurons, whereas non-myristoylated nuclear BASP1 acts as co-suppressor of the potent transcription regulator WT1 (Wilms' Tumor suppressor protein 1). Here we report NMR chemical shift assignment of recombinant human BASP1 fused to an N-terminal cleavable His6-tag.
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Affiliation(s)
- Leonhard Geist
- Department of Computational and Structural Biology, Max F. Perutz Laboratories, University of Vienna, Campus Vienna Biocenter 5, 1030 Vienna, Austria
| | | | - Saurabh Saxena
- Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland
| | - Szymon Żerko
- Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland
| | - Wiktor Koźmiński
- Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland
| | - Robert Konrat
- Department of Computational and Structural Biology, Max F. Perutz Laboratories, University of Vienna, Campus Vienna Biocenter 5, 1030 Vienna, Austria
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Stanek J, Saxena S, Geist L, Konrat R, Koźmiński W. Probing Local Backbone Geometries in Intrinsically Disordered Proteins by Cross-Correlated NMR Relaxation. Angew Chem Int Ed Engl 2013; 125:4702-4704. [PMID: 25821254 PMCID: PMC4373133 DOI: 10.1002/ange.201210005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Indexed: 11/22/2022]
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10
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Stanek J, Saxena S, Geist L, Konrat R, Koźmiński W. Probing local backbone geometries in intrinsically disordered proteins by cross-correlated NMR relaxation. Angew Chem Int Ed Engl 2013; 52:4604-6. [PMID: 23520002 PMCID: PMC3659411 DOI: 10.1002/anie.201210005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Indexed: 11/24/2022]
Affiliation(s)
- Jan Stanek
- Faculty of Chemistry, University of Warsaw, Pasteura 1, 02093 Warsaw, Poland
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11
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Yip CM. Correlative optical and scanning probe microscopies for mapping interactions at membranes. Methods Mol Biol 2013; 950:439-56. [PMID: 23086889 DOI: 10.1007/978-1-62703-137-0_24] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Innovative approaches for real-time imaging on molecular-length scales are providing researchers with powerful strategies for characterizing molecular and cellular structures and dynamics. Combinatorial techniques that integrate two or more distinct imaging modalities are particularly compelling as they provide a means for overcoming the limitations of the individual modalities and, when applied simultaneously, enable the collection of rich multi-modal datasets. Almost since its inception, scanning probe microscopy has closely associated with optical microscopy. This is particularly evident in the fields of cellular and molecular biophysics where researchers are taking full advantage of these real-time, in situ, tools to acquire three-dimensional molecular-scale topographical images with nanometer resolution, while simultaneously characterizing their structure and interactions though conventional optical microscopy. The ability to apply mechanical or optical stimuli provides an additional experimental dimension that has shown tremendous promise for examining dynamic events on sub-cellular length scales. In this chapter, we describe recent efforts in developing these integrated platforms, the methodology for, and inherent challenges in, performing coupled imaging experiments, and the potential and future opportunities of these research tools for the fields of molecular and cellular biophysics with a specific emphasis on the application of these coupled approaches for the characterization of interactions occurring at membrane interfaces.
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Affiliation(s)
- Christopher M Yip
- Department of Chemical Engineering and Applied Chemistry, Terrence Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, Canada.
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12
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Abstract
Caveolins (Cavs) are integrated plasma membrane proteins that are complex signaling regulators with numerous partners and whose activity is highly dependent on cellular context. Cavs are both positive and negative regulators of cell signaling in and/or out of caveolae, invaginated lipid raft domains whose formation is caveolin expression dependent. Caveolins and rafts have been implicated in membrane compartmentalization; proteins and lipids accumulate in these membrane microdomains where they transmit fast, amplified and specific signaling cascades. The concept of plasma membrane organization within functional rafts is still in exploration and sometimes questioned. In this chapter, we discuss the opposing functions of caveolin in cell signaling regulation focusing on the role of caveolin both as a promoter and inhibitor of different signaling pathways and on the impact of membrane domain localization on caveolin functionality in cell proliferation, survival, apoptosis and migration.
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13
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Takaichi R, Odagaki SI, Kumanogoh H, Nakamura S, Morita M, Maekawa S. Inhibitory effect of NAP-22 on the phosphatase activity of synaptojanin-1. J Neurosci Res 2011; 90:21-7. [DOI: 10.1002/jnr.22740] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2011] [Revised: 05/27/2011] [Accepted: 06/20/2011] [Indexed: 01/28/2023]
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14
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He HT, Marguet D. Detecting nanodomains in living cell membrane by fluorescence correlation spectroscopy. Annu Rev Phys Chem 2011; 62:417-36. [PMID: 21219145 DOI: 10.1146/annurev-physchem-032210-103402] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Cell membranes actively participate in numerous cellular functions. Inasmuch as bioactivities of cell membranes are known to depend crucially on their lateral organization, much effort has been focused on deciphering this organization on different length scales. Within this context, the concept of lipid rafts has been intensively discussed over recent years. In line with its ability to measure diffusion parameters with great precision, fluorescence correlation spectroscopy (FCS) measurements have been made in association with innovative experimental strategies to monitor modes of molecular lateral diffusion within the plasma membrane of living cells. These investigations have allowed significant progress in the characterization of the cell membrane lateral organization at the suboptical level and have provided compelling evidence for the in vivo existence of raft nanodomains. We review these FCS-based studies and the characteristic structural features of raft nanodomains. We also discuss the findings in regards to the current view of lipid rafts as a general membrane-organizing principle.
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Affiliation(s)
- Hai-Tao He
- Centre d'Immunologie de Marseille-Luminy, INSERM UMR-S 631, and Université de la Méditerranée, F-13288 Marseille cedex 09, France.
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15
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Mosevitsky M, Silicheva I. Subcellular and regional location of "brain" proteins BASP1 and MARCKS in kidney and testis. Acta Histochem 2011; 113:13-8. [PMID: 19683798 DOI: 10.1016/j.acthis.2009.07.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2009] [Revised: 07/12/2009] [Accepted: 07/13/2009] [Indexed: 01/04/2023]
Abstract
Proteins BASP1 and MARCKS are abundant in axonal endings of neurons. Similarly to brain-specific protein GAP-43, BASP1 and MARCKS are reversibly bound to the plasma membrane. These proteins control both actin polymerization and actin cytoskeleton binding to the membrane. Performing these functions, BASP1 and MARCKS take part in growth cone guidance during development and in neurotransmitter secretion in adults. These activities predetermine the pivotal role of BASP1 and MARCKS in learning and memory. BASP1 and MARCKS were also found in non-nerve tissues, in particular, in the kidney and testis. Evidently, the physiological roles of these proteins differ in different tissues. Correspondingly, their intracellular location and activities may not be similar to those in neurons. In this paper, we analyze subcellular fractions (cytoplasm and nuclei) of rat kidney and testis with the purpose of determining the intracellular location of BASP1 and MARCKS. Western blots demonstrated that in these tissues, as in the brain, both proteins are present in the cytoplasm of the cell. According to our immunohistochemical study, BASP1 and MARCKS are specifically distributed in the tissues studied. In kidney, both proteins are present in cells located in glomeruli. In the testicular tubules, BASP1 is mainly expressed at the late stage of spermatogenesis (in spermatids) and is preserved in mature spermatozoa, while MARCKS appears equally during all stages of spermatogenesis. MARCKS is not found in mature spermatozoa. The results indicate that study of functions of BASP1 and MARCKS in the kidney and in the reproduction system holds much promise.
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Affiliation(s)
- Mark Mosevitsky
- Petersburg Nuclear Physics Institute, Russian Academy of Sciences, Gatchina, Leningrad District, Russian Federation.
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16
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Ostroumova OS, Schagina LV, Mosevitsky MI, Zakharov VV. Ion channel activity of brain abundant protein BASP1 in planar lipid bilayers. FEBS J 2010; 278:461-9. [DOI: 10.1111/j.1742-4658.2010.07967.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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17
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Oligomeric structure of brain abundant proteins GAP-43 and BASP1. J Struct Biol 2010; 170:470-83. [PMID: 20109554 DOI: 10.1016/j.jsb.2010.01.010] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2009] [Revised: 12/21/2009] [Accepted: 01/20/2010] [Indexed: 11/19/2022]
Abstract
Brain abundant proteins GAP-43 and BASP1 participate in the regulation of actin cytoskeleton dynamics in neuronal axon terminals. The proposed mechanism suggests that the proteins sequester phosphatidylinositol-4,5-diphosphate (PIP(2)) in the inner leaflet of the plasma membrane. We found that model anionic phospholipid membranes in the form of liposomes induce rapid oligomerization of GAP-43 and BASP1 proteins. Multiply charged phosphoinositides produced the most potent effect. Anionic detergent sodium dodecyl sulfate (SDS) at submicellar concentration stimulated formation of similar oligomers in solution. BASP1, but not GAP-43, also formed oligomers at sufficiently high concentration in the absence of lipids and SDS. Electron microscopy study demonstrated that the oligomers have disk-shaped or annular structure of 10-30nm in diameter. BASP1 also formed higher aggregates of linear rod-like structure, with average length of about 100nm. In outward appearance, the oligomers and linear aggregates are reminiscent of oligomers and protofibrils of amyloid proteins. Both the synthetic N-terminal peptide GAP-43(1-40) and the brain-derived fragment GAP-43-3 preserved the ability to oligomerize under the action of acidic phospholipids and SDS. On the contrary, BASP1 fragment truncated by the short N-terminal myristoylated peptide was unable to form oligomers. GAP-43 and BASP1 oligomerization can be regulated by calmodulin, which disrupts the oligomers and displaces the proteins from the membrane. We suggest that in vivo, the role of membrane-bound GAP-43 and BASP1 oligomers consists in accumulation of PIP(2) in functional clusters, which become accessible for other PIP(2)-binding proteins after dissociation of the oligomers.
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Hayashi N, Titani K. N-myristoylated proteins, key components in intracellular signal transduction systems enabling rapid and flexible cell responses. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2010; 86:494-508. [PMID: 20467215 PMCID: PMC3108300 DOI: 10.2183/pjab.86.494] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/08/2010] [Accepted: 03/23/2010] [Indexed: 05/29/2023]
Abstract
N-myristoylation, one of the co- or post-translational modifications of proteins, has so far been regarded as necessary for anchoring of proteins to membranes. Recently, we have revealed that N(alpha)-myristoylation of several brain proteins unambiguously regulates certain protein-protein interactions that may affect signaling pathways in brain. Comparison of the amino acid sequences of myristoylated proteins including those in other organs suggests that this regulation is involved in signaling pathways not only in brain but also in other organs. Thus, it has been shown that myristoylated proteins in cells regulate the signal transduction between membranes and cytoplasmic fractions. An algorithm we have developed to identify myristoylated proteins in cells predicts the presence of hundreds of myristoylated proteins. Interestingly, a large portion of the myristoylated proteins thought to take part in signal transduction between membranes and cytoplasmic fractions are included in the predicted myristoylated proteins. If the proteins functionally regulated by myristoylation, a posttranslational protein modification, were understood as cross-talk points within the intracellular signal transduction system, known signaling pathways could thus be linked to each other, and a novel map of this intracellular network could be constructed. On the basis of our recent results, this review will highlight the multifunctional aspects of protein N-myristoylation in brain.
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Affiliation(s)
- Nobuhiro Hayashi
- Department of Life Science, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama-shi, Kanagawa Pref., 226-8501, Japan.
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19
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Abstract
Up to now less than a handful of viral cholesterol-binding proteins have been characterized, in HIV, influenza virus and Semliki Forest virus. These are proteins with roles in virus entry or morphogenesis. In the case of the HIV fusion protein gp41 cholesterol binding is attributed to a cholesterol recognition consensus (CRAC) motif in a flexible domain of the ectodomain preceding the trans-membrane segment. This specific CRAC sequence mediates gp41 binding to a cholesterol affinity column. Mutations in this motif arrest virus fusion at the hemifusion stage and modify the ability of the isolated CRAC peptide to induce segregation of cholesterol in artificial membranes.Influenza A virus M2 protein co-purifies with cholesterol. Its proton translocation activity, responsible for virus uncoating, is not cholesterol-dependent, and the transmembrane channel appears too short for integral raft insertion. Cholesterol binding may be mediated by CRAC motifs in the flexible post-TM domain, which harbours three determinants of binding to membrane rafts. Mutation of the CRAC motif of the WSN strain attenuates virulence for mice. Its affinity to the raft-non-raft interface is predicted to target M2 protein to the periphery of lipid raft microdomains, the sites of virus assembly. Its influence on the morphology of budding virus implicates M2 as factor in virus fission at the raft boundary. Moreover, M2 is an essential factor in sorting the segmented genome into virus particles, indicating that M2 also has a role in priming the outgrowth of virus buds.SFV E1 protein is the first viral type-II fusion protein demonstrated to directly bind cholesterol when the fusion peptide loop locks into the target membrane. Cholesterol binding is modulated by another, proximal loop, which is also important during virus budding and as a host range determinant, as shown by mutational studies.
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Affiliation(s)
- Cornelia Schroeder
- Max Planck Institute for Molecular Cell Biology and Genetics, Pfotenhauerstr. 108, D-01307, Dresden, Germany.
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20
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Hao M, Bogan JS. Cholesterol regulates glucose-stimulated insulin secretion through phosphatidylinositol 4,5-bisphosphate. J Biol Chem 2009; 284:29489-98. [PMID: 19729450 DOI: 10.1074/jbc.m109.038034] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Membrane cholesterol modulates the ability of glucose to stimulate insulin secretion from pancreatic beta-cells. The molecular mechanism by which this occurs is not understood. Here, we show that in cultured beta-cells, cholesterol acts through phosphatidylinositol 4,5-bisphosphate (PIP(2)) to regulate actin dynamics, plasma membrane potential, and glucose-stimulated insulin secretion. Cholesterol-overloaded beta-cells exhibited decreased PIP(2) hydrolysis, with diminished glucose-induced actin reorganization, membrane depolarization, and insulin secretion. The converse findings were observed in cholesterol-depleted cells. These results support a model in which cholesterol depletion is coupled through PIP(2) to enhance both plasma membrane Ca2+ influx from the extracellular space, as well as inositol 1,4,5-triphosphate-stimulated Ca2+ efflux from intracellular stores. The inability to increase cytosolic Ca2+ may be the main underlying factor to account for impaired glucose-stimulated insulin secretion in cholesterol-overloaded beta-cells.
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Affiliation(s)
- Mingming Hao
- Section of Endocrinology and Metabolism, Department of Internal Medicine, Yale University, P.O. Box 208020, New Haven, CT 06520-8020, USA.
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21
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A possible effector role for the pleckstrin homology (PH) domain of dynamin. Proc Natl Acad Sci U S A 2009; 106:13359-64. [PMID: 19666604 DOI: 10.1073/pnas.0906945106] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The large GTPase dynamin plays a key role in clathrin-mediated endocytosis in animal cells, although its mechanism of action remains unclear. Dynamins 1, 2, and 3 contain a pleckstrin homology (PH) domain that binds phosphoinositides with a very low affinity (K(D) > 1 mM), and this interaction appears to be crucial for function. These observations prompted the suggestion that an array of PH domains drives multivalent binding of dynamin oligomers to phosphoinositide-containing membranes. Although in vitro experiments reported here are consistent with this hypothesis, we find that PH domain mutations that abolish dynamin function do not alter localization of the protein in transfected cells, indicating that the PH domain does not play a simple targeting role. An alternative possibility is suggested by the geometry of dynamin helices resolved by electron microscopy. Even with one phosphatidylinositol-4,5-bisphosphate [PtdIns(4,5)P(2)] molecule bound per PH domain, these dynamin assemblies will elevate the concentration of PtdIns(4,5)P(2) at coated pit necks, and effectively cluster (or sequester) this phosphoinositide. In vitro fluorescence quenching studies using labeled phosphoinositides are consistent with dynamin-induced PtdIns(4,5)P(2) clustering. We therefore propose that the ability of dynamin to alter the local distribution of PtdIns(4,5)P(2) could be crucial for the role of this GTPase in promoting membrane scission during clathrin-mediated endocytosis. PtdIns(4,5)P(2) clustering could promote vesicle scission through direct effects on membrane properties, or might play a role in dynamin's ability to regulate actin polymerization.
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22
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Hammond GRV, Sim Y, Lagnado L, Irvine RF. Reversible binding and rapid diffusion of proteins in complex with inositol lipids serves to coordinate free movement with spatial information. ACTA ACUST UNITED AC 2009; 184:297-308. [PMID: 19153221 PMCID: PMC2654307 DOI: 10.1083/jcb.200809073] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Polyphosphoinositol lipids convey spatial information partly by their interactions with cellular proteins within defined domains. However, these interactions are prevented when the lipids' head groups are masked by the recruitment of cytosolic effector proteins, whereas these effectors must also have sufficient mobility to maximize functional interactions. To investigate quantitatively how these conflicting functional needs are optimized, we used different fluorescence recovery after photobleaching techniques to investigate inositol lipid–effector protein kinetics in terms of the real-time dissociation from, and diffusion within, the plasma membrane. We find that the protein–lipid complexes retain a relatively rapid (∼0.1–1 µm2/s) diffusion coefficient in the membrane, likely dominated by protein–protein interactions, but the limited time scale (seconds) of these complexes, dictated principally by lipid–protein interactions, limits their range of action to a few microns. Moreover, our data reveal that GAP1IP4BP, a protein that binds PtdIns(4,5)P2 and PtdIns(3,4,5)P3 in vitro with similar affinity, is able to “read” PtdIns(3,4,5)P3 signals in terms of an elongated residence time at the membrane.
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Affiliation(s)
- Gerald R V Hammond
- Department of Pharmacology, University of Cambridge, Cambridge, England, UK.
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23
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Musse AA, Gao W, Rangaraj G, Boggs JM, Harauz G. Myelin basic protein co-distributes with other PI(4,5)P2-sequestering proteins in Triton X-100 detergent-resistant membrane microdomains. Neurosci Lett 2009; 450:32-6. [DOI: 10.1016/j.neulet.2008.11.022] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2008] [Revised: 11/06/2008] [Accepted: 11/09/2008] [Indexed: 10/21/2022]
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Musse AA, Gao W, Homchaudhuri L, Boggs JM, Harauz G. Myelin basic protein as a "PI(4,5)P2-modulin": a new biological function for a major central nervous system protein. Biochemistry 2008; 47:10372-82. [PMID: 18767817 DOI: 10.1021/bi801302b] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The 18.5 kDa isoform of myelin basic protein (MBP) is multifunctional and has previously been shown to have structural and phenomenological similarities with domains of other membrane- and cytoskeleton-associated proteins such as MARCKS (myristoylated alanine-rich C kinase substrate). Here, we have investigated whether 18.5 kDa MBP can sequester phosphatidylinositol-(4,5)-bis-phosphate (PI(4,5)P 2) in membranes, like MARCKS and other "PIPmodulins" do. Using fluorescence-quenching and electron paramagnetic resonance (EPR) spectroscopy, and model membranes containing BODIPY-FL- or proxyl-labeled PI(4,5)P 2, respectively, we have demonstrated that MBP laterally sequesters PI(4,5)P 2. The MBP-PI(4,5)P 2 interactions are electrostatic, partially cholesterol-dependent, and sensitive to phosphorylation, deimination, and Ca (2+)-CaM binding. Confocal microscopy of cultured oligodendrocytes also revealed patched colocalization of MBP and PI(4,5)P 2, indicating the spatial clustering of PI(4,5)P 2 in the plasma membrane. On the basis of these findings as well as the overwhelming convergence of functional properties, modifying enzymes, and interaction partners, we propose that MBP is mechanistically related to GAP-43, MARCKS, and CAP-23. During myelinogenesis, it may mediate calcium and phosphorylation-sensitive plasma membrane availability of PI(4,5)P 2. This regulation of PI(4,5)P 2 availability at the cell cortex may be coupled to the elaboration and outgrowth of the membranous cellular processes by oligodendrocytes.
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Affiliation(s)
- Abdiwahab A Musse
- Department of Molecular and Cellular Biology and Biophysics Interdepartmental Group, University of Guelph, 50 Stone Road East, Guelph, Ontario, Canada, N1G 2W1
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25
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Lasserre R, Guo XJ, Conchonaud F, Hamon Y, Hawchar O, Bernard AM, Soudja SM, Lenne PF, Rigneault H, Olive D, Bismuth G, Nunès JA, Payrastre B, Marguet D, He HT. Raft nanodomains contribute to Akt/PKB plasma membrane recruitment and activation. Nat Chem Biol 2008; 4:538-47. [PMID: 18641634 DOI: 10.1038/nchembio.103] [Citation(s) in RCA: 225] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2008] [Accepted: 06/27/2008] [Indexed: 01/14/2023]
Abstract
Membrane rafts are thought to be sphingolipid- and cholesterol-dependent lateral assemblies involved in diverse cellular functions. Their biological roles and even their existence, however, remain controversial. Using an original fluorescence correlation spectroscopy strategy that recently enabled us to identify nanoscale membrane organizations in live cells, we report here that highly dynamic nanodomains exist in both the outer and inner leaflets of the plasma membrane. Through specific inhibition of biosynthesis, we show that sphingolipids and cholesterol are essential and act in concert for formation of nanodomains, thus corroborating their raft nature. Moreover, we find that nanodomains play a crucial role in triggering the phosphatidylinositol-3 kinase/Akt signaling pathway, by facilitating Akt recruitment and activation upon phosphatidylinositol-3,4,5-triphosphate accumulation in the plasma membrane. Thus, through direct monitoring and controlled alterations of rafts in living cells, we demonstrate that rafts are critically involved in the activation of a signaling axis that is essential for cell physiology.
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Affiliation(s)
- Rémi Lasserre
- Centre d'Immunologie de Marseille-Luminy, Université de la Méditerranée, Parc scientifique de Luminy, Case 906, F-13288 Marseille Cedex 09, France
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26
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Oreopoulos J, Yip CM. Combined scanning probe and total internal reflection fluorescence microscopy. Methods 2008; 46:2-10. [PMID: 18602010 DOI: 10.1016/j.ymeth.2008.05.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2008] [Accepted: 05/22/2008] [Indexed: 11/19/2022] Open
Abstract
Combining scanning probe and optical microscopy represents a powerful approach for investigating structure-function relationships and dynamics of biomolecules and biomolecular assemblies, often in situ and in real-time. This platform technology allows us to obtain three-dimensional images of individual molecules with nanometer resolution, while simultaneously characterizing their structure and interactions though complementary techniques such as optical microscopy and spectroscopy. We describe herein the practical strategies for the coupling of scanning probe and total internal reflection fluorescence microscopy along with challenges and the potential applications of such platforms, with a particular focus on their application to the study of biomolecular interactions at membrane surfaces.
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Affiliation(s)
- John Oreopoulos
- Institute of Biomaterials and Biomedical Engineering, Terrence Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College St, Toronto, Ont., Canada M5S 3E1
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27
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Epand RM. Proteins and cholesterol-rich domains. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2008; 1778:1576-82. [DOI: 10.1016/j.bbamem.2008.03.016] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2007] [Revised: 03/19/2008] [Accepted: 03/24/2008] [Indexed: 12/21/2022]
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28
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Jin H, McCaffery JM, Grote E. Ergosterol promotes pheromone signaling and plasma membrane fusion in mating yeast. ACTA ACUST UNITED AC 2008; 180:813-26. [PMID: 18299351 PMCID: PMC2265586 DOI: 10.1083/jcb.200705076] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Ergosterol depletion independently inhibits two aspects of yeast mating: pheromone signaling and plasma membrane fusion. In signaling, ergosterol participates in the recruitment of Ste5 to a polarized site on the plasma membrane. Ergosterol is thought to form microdomains within the membrane by interacting with the long acyl chains of sphingolipids. We find that although sphingolipid-free ergosterol is concentrated at sites of cell–cell contact, transmission of the pheromone signal at contact sites depends on a balanced ratio of ergosterol to sphingolipids. If a mating pair forms between ergosterol-depleted cells despite the attenuated pheromone response, the subsequent process of membrane fusion is retarded. Prm1 also participates in membrane fusion. However, ergosterol and Prm1 have independent functions and only prm1 mutant mating pairs are susceptible to contact-dependent lysis. In contrast to signaling, plasma membrane fusion is relatively insensitive to sphingolipid depletion. Thus, the sphingolipid-free pool of ergosterol promotes plasma membrane fusion.
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Affiliation(s)
- Hui Jin
- Department of Biochemistry and Molecular Biology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA
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29
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Redfern RE, Redfern D, Furgason MLM, Munson M, Ross AH, Gericke A. PTEN Phosphatase Selectively Binds Phosphoinositides and Undergoes Structural Changes. Biochemistry 2008; 47:2162-71. [DOI: 10.1021/bi702114w] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Roberta E. Redfern
- Chemistry Department, Kent State University, Kent, Ohio 44242, and Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01605
| | - Duane Redfern
- Chemistry Department, Kent State University, Kent, Ohio 44242, and Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01605
| | - Melonnie L. M. Furgason
- Chemistry Department, Kent State University, Kent, Ohio 44242, and Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01605
| | - Mary Munson
- Chemistry Department, Kent State University, Kent, Ohio 44242, and Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01605
| | - Alonzo H. Ross
- Chemistry Department, Kent State University, Kent, Ohio 44242, and Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01605
| | - Arne Gericke
- Chemistry Department, Kent State University, Kent, Ohio 44242, and Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01605
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30
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Epand RM. Detecting the presence of membrane domains using DSC. Biophys Chem 2006; 126:197-200. [PMID: 16730877 DOI: 10.1016/j.bpc.2006.05.008] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2006] [Accepted: 05/10/2006] [Indexed: 11/24/2022]
Abstract
Both biological and model liposomal membranes have unequal distribution of molecular components in the plane of the membrane. There is increasing interest to determine the composition and properties of membrane domains enriched with specific molecular components. Several methodologies have been applied to study this. Each has its own advantages and provides a particular kind of information. In the present article, we will focus on the application of differential scanning calorimetry to the determination of the distribution of molecules into membrane domains with particular emphasis on protein and peptide-induced domain formation.
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Affiliation(s)
- Richard M Epand
- Department of Biochemistry and Biomedical Sciences, McMaster University Health Sciences Centre, Hamilton, ON, Canada L8N 3Z5.
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31
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Fernandes F, Loura LMS, Fedorov A, Prieto M. Absence of clustering of phosphatidylinositol-(4,5)-bisphosphate in fluid phosphatidylcholine. J Lipid Res 2006; 47:1521-5. [PMID: 16632797 DOI: 10.1194/jlr.m600121-jlr200] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Phosphatidylinositol-(4,5)-bisphosphate [PI(4,5)P(2)] plays a key role in the modulation of actin polymerization and vesicle trafficking. These processes seem to depend on the enrichment of PI(4,5)P(2) in plasma membrane domains. Here, we show that PI(4,5)P(2) does not form domains when in a fluid phosphatidylcholine matrix in the pH range of 4.8-8.4. This finding is at variance with the spontaneous segregation of PI(4,5)P(2) to domains as a mechanism for the compartmentalization of PI(4,5)P(2) in the plasma membrane. Water/bilayer partition of PI(4,5)P(2) is also shown to be dependent on the protonation state of the lipid.
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Affiliation(s)
- Fábio Fernandes
- Centro de Química-Física Molecular, Instituto Superior Técnico, Lisbon, Portugal.
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32
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Epand RM, Rychnovsky SD, Belani JD, Epand RF. Role of chirality in peptide-induced formation of cholesterol-rich domains. Biochem J 2006; 390:541-8. [PMID: 15929726 PMCID: PMC1198934 DOI: 10.1042/bj20050649] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The chiral specificity of the interactions of peptides that induce the formation of cholesterol-rich domains has not been extensively investigated. Both the peptide and most lipids are chiral, so there is a possibility that interactions between peptide and lipid could require chiral recognition. On the other hand, in our models with small peptides, the extent of folding of the peptide to form a specific binding pocket is limited. We have determined that replacing cholesterol with its enantiomer, ent-cholesterol, alters the modulation of lipid organization by peptides. The phase-transition properties of SOPC (1-stearoyl-2-oleoylphosphatidylcholine):cholesterol [in a 6:4 ratio with 0.2 mol% PtdIns(4,5)P2] are not significantly altered when ent-cholesterol replaces cholesterol. However, in the presence of 10 mol% of a 19-amino-acid, N-terminally myristoylated fragment (myristoyl-GGKLSKKKKGYNVNDEKAK-amide) of the protein NAP-22 (neuronal axonal membrane protein), the lipid mixture containing cholesterol undergoes separation into cholesterol-rich and cholesterol-depleted domains. This does not occur when ent-cholesterol replaces cholesterol. In another example, when N-acetyl-Leu-Trp-Tyr-Ile-Lys-amide (N-acetyl-LWYIK-amide) is added to SOPC:cholesterol (7:3 ratio), there is a marked increase in the transition enthalpy of the phospholipid, indicating separation of a cholesterol-depleted domain of SOPC. This phenomenon completely disappears when ent-cholesterol replaces cholesterol. The all-D-isomer of N-acetyl-LWYIK-amide also induces the formation of cholesterol-rich domains with natural cholesterol, but does so to a lesser extent with ent-cholesterol. Thus specific peptide chirality is not required for interaction with cholesterol-containing membranes. However, a specific chirality of membrane lipids is required for peptide-induced formation of cholesterol-rich domains.
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Affiliation(s)
- Richard M Epand
- Department of Biochemistry, McMaster University, 1200 Main Street West, Hamilton, Ontario, Canada L8N 3Z5.
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33
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Epand RF, Sayer BG, Epand RM. Induction of raft-like domains by a myristoylated NAP-22 peptide and its Tyr mutant. FEBS J 2005; 272:1792-803. [PMID: 15794765 DOI: 10.1111/j.1742-4658.2005.04612.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The N-terminally myristoylated, 19-amino acid peptide, corresponding to the amino terminus of the neuronal protein NAP-22 (NAP-22 peptide) is a naturally occurring peptide that had been shown by fluorescence to cause the sequestering of a Bodipy-labeled PtdIns(4,5)P2 in a cholesterol-dependent manner. The present work, using differential scanning calorimetry (DSC), extends the observation that formation of a PtdIns(4,5)P2-rich domain is cholesterol dependent and shows that it also leads to the formation of a cholesterol-depleted domain. The PtdIns(4,5)P2 used in the present work is extracted from natural sources and does not contain any label and has the native acyl chain composition. Peptide-induced formation of a cholesterol-depleted domain is abolished when the sole aromatic amino acid, Tyr11 is replaced with a Leu. Despite this, the modified peptide can still sequester PtdIns(4,5)P2 into domains, probably because of the presence of a cluster of cationic residues in the peptide. Cholesterol and PtdIns(4,5)P2 also modulate the insertion of the peptide into the bilayer as revealed by 1H NOESY MAS/NMR. The intensity of cross peaks between the aromatic protons of the Tyr residue and the protons of the lipid indicate that in the presence of cholesterol there is a change in the nature of the interaction of the peptide with the membrane. These results have important implications for the mechanism by which NAP-22 affects actin reorganization in neurons.
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Affiliation(s)
- Raquel F Epand
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON Canada.
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34
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Redfern DA, Gericke A. pH-dependent domain formation in phosphatidylinositol polyphosphate/phosphatidylcholine mixed vesicles. J Lipid Res 2005; 46:504-15. [PMID: 15604522 DOI: 10.1194/jlr.m400367-jlr200] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Phosphatidylinositol polyphosphates (PI-PPs) have been shown to mediate a large variety of physiological processes by attracting proteins to specific cellular sites. Such site-specific signaling requires local accumulation of PI-PPs, and in light of the rich headgroup functionality, it is conceivable that hydrogen bond formation between adjacent headgroups is a contributing factor to the formation of PI-PP-enriched domains. To explore the significance of hydrogen bond formation for the mutual interaction of PI-PPs, this study aims to characterize the pH-dependent phase behavior of phosphatidylcholine/phosphatidylinositol bisphosphate and trisphosphate mixed vesicles by differential scanning calorimetry, infrared transmission spectroscopy, and fluorescence resonance energy transfer measurements. For pH values >7-7.5, the experiments yielded results consistent with dipalmitoylphosphatidylcholine/dipalmitoylphosphatidylinositol polyphosphate gel phase demixing, whereas for moderately acidic conditions, an enhanced mixing was observed. Similarly, this pH-dependent formation of PI-PP-enriched domains was also found for the physiologically important fluid phase. The stability of PI-PP-enriched domains and to some extent the pH dependence of the domain formation was governed by the number as well as the position of the phosphomonoester groups at the inositol ring.
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Affiliation(s)
- Duane A Redfern
- Chemistry Department, Kent State University, Kent, OH 44242, USA
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35
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Epand RM. Do proteins facilitate the formation of cholesterol-rich domains? BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2005; 1666:227-38. [PMID: 15519317 DOI: 10.1016/j.bbamem.2004.07.004] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2004] [Revised: 07/21/2004] [Accepted: 07/23/2004] [Indexed: 01/10/2023]
Abstract
Both biological and model membranes can exhibit the formation of domains. A brief review of some of the diverse methodologies used to identify the presence of domains in membranes is given. Some of these domains are enriched in cholesterol. The segregation of lipids into cholesterol-rich domains can occur in both pure lipid systems as well as membranes containing peptides and proteins. Peptides and proteins can promote the formation of cholesterol-rich domains not only by preferentially interacting with cholesterol and being sequestered into these regions of the membrane, but also indirectly as a consequence of being excluded from cholesterol-rich domains. The redistribution of components is dictated by the thermodynamics of the system. The formation of domains in a biological membrane is a consequence of all of the intermolecular interactions including those among lipid molecules as well as between lipids and proteins.
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Affiliation(s)
- Richard M Epand
- Department of Biochemistry, McMaster University Hamilton, ON L8N 3Z5, Canada.
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36
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Mosevitsky MI. Nerve Ending “Signal” Proteins GAP‐43, MARCKS, and BASP1. INTERNATIONAL REVIEW OF CYTOLOGY 2005; 245:245-325. [PMID: 16125549 DOI: 10.1016/s0074-7696(05)45007-x] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Mechanisms of growth cone pathfinding in the course of neuronal net formation as well as mechanisms of learning and memory have been under intense investigation for the past 20 years, but many aspects of these phenomena remain unresolved and even mysterious. "Signal" proteins accumulated mainly in the axon endings (growth cones and the presynaptic area of synapses) participate in the main brain processes. These proteins are similar in several essential structural and functional properties. The most prominent similarities are N-terminal fatty acylation and the presence of an "effector domain" (ED) that dynamically binds to the plasma membrane, to calmodulin, and to actin fibrils. Reversible phosphorylation of ED by protein kinase C modulates these interactions. However, together with similarities, there are significant differences among the proteins, such as different conditions (Ca2+ contents) for calmodulin binding and different modes of interaction with the actin cytoskeleton. In light of these facts, we consider GAP-43, MARCKS, and BASP1 both separately and in conjunction. Special attention is devoted to a discussion of apparent inconsistencies in results and opinions of different authors concerning specific questions about the structure of proteins and their interactions.
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Affiliation(s)
- Mark I Mosevitsky
- Division of Molecular and Radiation Biophysics, Petersburg Nuclear Physics Institute, Russian Academy of Sciences, 188300 Gatchina Leningrad District, Russian Federation
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