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Wang W, Zhang H, Nayak BP, Vaknin D. Specific iron binding to natural sphingomyelin membrane induced by non-specific co-solutes. J Colloid Interface Sci 2025; 679:307-315. [PMID: 39366260 DOI: 10.1016/j.jcis.2024.09.194] [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: 08/19/2024] [Revised: 09/19/2024] [Accepted: 09/23/2024] [Indexed: 10/06/2024]
Abstract
HYPOTHESIS Sphingomyelin (SPM), a crucial phospholipid in the myelin sheath, plays a vital role in insulating nerve fibers. We hypothesize that iron ions selectively bind to the phosphatidylcholine (PC) template within the SPM membrane under near-physiological conditions, resulting in disruptions to membrane organization. These interactions could potentially contribute to the degradation of the myelin sheath, thereby playing a role in the development of neurodegenerative diseases. EXPERIMENTS We utilized synchrotron-based X-ray spectroscopy and diffraction techniques to study the interaction of iron ions with a bovine spinal-cord SPM monolayer (ML) at the liquid-vapor interface under physiological conditions. The SPM ML serves as a model system, representing localized patches of lipids within a more complex membrane structure. The experiments assessed iron binding to the SPM membrane both in the presence of salts and with additional evaluation of the effects of various ion species on membrane behavior. Grazing incidence X-ray diffraction was employed to analyze the impact of iron binding on the structural integrity of the SPM membrane. FINDINGS Our results demonstrate that iron ions in dilute solution selectively bind to the PC template of the SPM membrane exclusively at near-physiological salt concentrations (e.g., NaCl, KCl, KI, or CaCl2) and are pH-dependent. In-significant binding was detected in the absence of these salts or at near-neutral pH with salts. The surface adsorption of iron ions is correlated with salt concentration, reaching saturation at physiological levels. In contrast, multivalent ions such as La3+ and Ca2+ do not bind to SPM under similar conditions. Notably, iron binding to the SPM membrane disrupts its in-plane organization, suggesting that these interactions may compromise membrane integrity and contribute to myelin sheath damage associated with neurological disorders.
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Affiliation(s)
- Wenjie Wang
- Division of Materials Sciences and Engineering, Ames National Laboratory, U.S. DOE, Ames, IA 50011, United States
| | - Honghu Zhang
- Ames National Laboratory, and Department of Materials Science and Engineering, Iowa State University, Ames, IA 50011, United States
| | - Binay P Nayak
- Ames National Laboratory, and Department of Chemical and Biological Engineering, Iowa State University, Ames, IA 50011, United States
| | - David Vaknin
- Ames National Laboratory, and Department of Physics and Astronomy, Iowa State University, Ames, IA 50011, United States.
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2
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Bernstein AD, Asante Ampadu GA, Yang Y, Acharya GR, Osborn Popp TM, Nieuwkoop AJ. Effects of Ca 2+ on the Structure and Dynamics of PIP 3 in Model Membranes Containing PC and PS. Biochemistry 2024. [PMID: 39656263 DOI: 10.1021/acs.biochem.4c00513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2024]
Abstract
Phosphatidylinositol phosphates (PIPs) are a family of seven different eukaryotic membrane lipids that have a large role in cell viability, despite their minor concentration in eukaryotic cellular membranes. PIPs tightly regulate cellular processes, such as cellular growth, metabolism, immunity, and development through direct interactions with partner proteins. Understanding the biophysical properties of PIPs in the complex membrane environment is important to understand how PIPs selectively regulate a partner protein. Here, we investigate the structure and dynamics of PIP3 in lipid bilayers that are simplified models of the natural membrane environment. We probe the effects of the anionic lipid phosphatidylserine (PS) and the divalent cation Ca2+ by using full-length lipids in well-formed bilayers. We used solution and solid-state NMR on naturally abundant 1H, 31P, and 13C atoms combined with molecular dynamics (MD) simulations to characterize the structure and dynamics of PIPs. 1H and 31P 1D spectra show good resolution at temperatures above the phase transition with isolated peaks in the headgroup, interfacial, and bilayer regions. Site-specific assignment of the chemical shifts of these reporters enables the measurement of the effects of Ca2+ and PS at the single atom level. In particular, the resolved 31P signals of the PIP3 headgroup allow for extremely well-localized information about PIP3 phosphate dynamics, which the MD simulations can further explain. A quantitative assessment of cross-polarization kinetics provides additional dynamics measurements for the PIP3 headgroups.
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Affiliation(s)
- Ashley D Bernstein
- Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, United States
| | - Gertrude A Asante Ampadu
- Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, United States
| | - Yanxing Yang
- Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, United States
| | - Gobin Raj Acharya
- Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, United States
| | - Thomas M Osborn Popp
- Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, United States
| | - Andrew J Nieuwkoop
- Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, United States
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3
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Bernstein AD, Yang Y, Osborn Popp TM, Ampadu GA, Acharya GR, Nieuwkoop AJ. Effects of Ca 2+ on the Structure and Dynamics of PIP3 in Model Membranes Containing PC and PS. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.28.596302. [PMID: 38854128 PMCID: PMC11160587 DOI: 10.1101/2024.05.28.596302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
Phosphatidylinositol phosphates (PIPs) are a family of seven different eukaryotic membrane lipids that have a large role in cell viability, despite their minor concentration in eukaryotic cellular membranes. PIPs tightly regulate cellular processes such as cellular growth, metabolism, immunity, and development through direct interactions with partner proteins. Understanding the biophysical properties of PIPs in the complex membrane environment is important to understand how PIPs selectively regulate a partner protein. Here we investigate the structure and dynamics of PIP3 in lipid bilayers that are simplified models of the natural membrane environment. We probe the effects of the anionic lipid phosphatidylserine (PS) and the divalent cation Ca 2+ . We use solution and solid-state 1 H, 31 P, and 13 C NMR all at natural abundance combined with MD simulations to characterize the structure and dynamics of PIPs. 1 H and 31 P 1D spectra show good resolution at high temperatures with isolated peaks in the headgroup, interfacial, and bilayer regions. Site specific assignment of these 1D reporters were made and used to measure the effects of Ca 2+ and PS. In particular, the resolved 31 P signals of the PIP3 headgroup allowed for extremely well localized information about PIP3 phosphate dynamics, which the MD simulations were able to help explain. Cross polarization kinetics provided additional site-specific dynamics measurements for the PIP3 headgroups.
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4
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Jarin Z, Venable RM, Han K, Pastor RW. Ion-Induced PIP2 Clustering with Martini3: Modification of Phosphate-Ion Interactions and Comparison with CHARMM36. J Phys Chem B 2024; 128:2134-2143. [PMID: 38393820 PMCID: PMC11686486 DOI: 10.1021/acs.jpcb.3c06523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2024]
Abstract
Phosphatidylinositol 4,5-bisphosphate (PIP2) is a critical lipid for cellular signaling. The specific phosphorylation of the inositol ring controls protein binding as well as clustering behavior. Two popular models to describe ion-mediated clustering of PIP2 are Martini3 (M3) and CHARMM36 (C36). Molecular dynamics simulations of PIP2-containing bilayers in solutions of potassium chloride, sodium chloride, and calcium chloride, and at two different resolutions are performed to understand the aggregation and the model parameters that drive it. The average M3 clusters of PIP2 in bilayers of 1-palmitoyl-2-oleoyl-glycero-3-phosphocholine and PIP2 bilayers in the presence of K+, Na+, or Ca2+ contained 2.2, 2.6, and 6.4 times more PIP2 than C36 clusters, respectively. Indeed, the Ca2+-containing systems often formed a single large aggregate. Reparametrization of the M3 ion-phosphate Lennard-Jones interaction energies to reproduce experimental osmotic pressure of sodium dimethyl phosphate (DMP), K[DMP], and Ca[DMP]2 solutions, the same experimental target as C36, yielded comparably sized PIP2 clusters for the two models. Furthermore, C36 and the modified M3 predict similar saturation of the phosphate groups with increasing Ca2+, although the coarse-grained model does not capture the cooperativity between K+ and Ca2+. This characterization of the M3 behavior in the presence of monovalent and divalent ions lays a foundation to study cation/protein/PIP2 clustering.
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Affiliation(s)
- Zack Jarin
- Laboratory of Computational Biology, National Heart, Lung, and Blood Institute, National Institutes of Health, Rockville, Maryland 20892, United States
| | - Richard M Venable
- Laboratory of Computational Biology, National Heart, Lung, and Blood Institute, National Institutes of Health, Rockville, Maryland 20892, United States
| | - Kyungreem Han
- Laboratory of Computational Neurophysics, Center for Brain Technology, Brain Science Institute, Korea Institute of Science and Technology, Seoul 02792, Korea
| | - Richard W Pastor
- Laboratory of Computational Biology, National Heart, Lung, and Blood Institute, National Institutes of Health, Rockville, Maryland 20892, United States
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5
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Design principles of PI(4,5)P 2 clustering under protein-free conditions: Specific cation effects and calcium-potassium synergy. Proc Natl Acad Sci U S A 2022; 119:e2202647119. [PMID: 35605121 DOI: 10.1073/pnas.2202647119] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
SignificanceClustering of phosphatidylinositol 4,5-bisphosphate (PIP2) with proteins into what are known as "PIP2 rafts" is a critical component of intracellular signaling, yet little is known about PIP2 clusters at the atomic level. Using molecular dynamics simulations and network theory, this paper shows that Ca2+ generates large clusters by linking PIP2 dimers already formed by doubly charged P4/P5 phosphates, while monovalent cations form smaller and less-stable clusters by adding PIP2 monomers preferentially via weaker interactions with P4/P5 (for Na+) or with glycerol P1 (for K+). Synergy arises between K+ and Ca2+ because each ion forms linkages with different phosphates, thereby giving clusters more ways to grow. This explains why Ca2+ is pumped into cells by ion channels to form PIP2 rafts.
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6
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The Electrostatic Basis of Diacylglycerol Pyrophosphate—Protein Interaction. Cells 2022; 11:cells11020290. [PMID: 35053406 PMCID: PMC8774204 DOI: 10.3390/cells11020290] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Revised: 01/04/2022] [Accepted: 01/07/2022] [Indexed: 01/08/2023] Open
Abstract
Diacylglycerol pyrophosphate (DGPP) is an anionic phospholipid formed in plants, yeast, and parasites under multiple stress stimuli. It is synthesized by the phosphorylation action of phosphatidic acid (PA) kinase on phosphatidic acid, a signaling lipid with multifunctional properties. PA functions in the membrane through the interaction of its negatively charged phosphomonoester headgroup with positively charged proteins and ions. DGPP, like PA, can interact electrostatically via the electrostatic-hydrogen bond switch mechanism but differs from PA in its overall charge and shape. The formation of DGPP from PA alters the physicochemical properties as well as the structural dynamics of the membrane. This potentially impacts the molecular and ionic binding of cationic proteins and ions with the DGPP enriched membrane. However, the results of these important interactions in the stress response and in DGPP’s overall intracellular function is unknown. Here, using 31P MAS NMR, we analyze the effect of the interaction of low DGPP concentrations in model membranes with the peptides KALP23 and WALP23, which are flanked by positively charged Lysine and neutral Tryptophan residues, respectively. Our results show a significant effect of KALP23 on the charge of DGPP as compared to WALP23. There was, however, no significant effect on the charge of the phosphomonoester of DGPP due to the interaction with positively charged lipids, dioleoyl trimethylammonium propane (DOTAP) and dioleoyl ethyl-phosphatidylcholine (EtPC). Divalent calcium and magnesium cations induce deprotonation of the DGPP headgroup but showed no noticeable differences on DGPP’s charge. Our results lead to a novel model for DGPP—protein interaction.
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7
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Mahata S, Janani G, Mandal BB, Manivannan V. A coumarin based visual and fluorometric probe for selective detection of Al(III), Cr(III) and Fe(III) ions through “turn-on” response and its biological application. J Photochem Photobiol A Chem 2021. [DOI: 10.1016/j.jphotochem.2021.113340] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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8
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Daear W, Mundle R, Sule K, Prenner EJ. The degree and position of phosphorylation determine the impact of toxic and trace metals on phosphoinositide containing model membranes. BBA ADVANCES 2021; 1:100021. [PMID: 37082006 PMCID: PMC10074965 DOI: 10.1016/j.bbadva.2021.100021] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
This work assessed effects of metal binding on membrane fluidity, liposome size, and lateral organization in biomimetic membranes composed of 1 mol% of selected phosphorylated phosphoinositides in each system. Representative examples of phosphoinositide phosphate, bisphosphate and triphosphate were investigated. These include phosphatidylinositol-(4,5)-bisphosphate, an important signaling lipid constituting a minor component in plasma membranes whereas phosphatidylinositol-(4,5)-bisphosphate clusters support the propagation of secondary messengers in numerous signaling pathways. The high negative charge of phosphoinositides facilitates electrostatic interactions with metals. Lipids are increasingly identified as toxicological targets for divalent metals, which potentially alter lipid packing and domain formation. Exposure to heavy metals, such as lead and cadmium or elevated levels of essential metals, like cobalt, nickel, and manganese, implicated with various toxic effects were investigated. Phosphatidylinositol-(4)-phosphate and phosphatidylinositol-(3,4,5)-triphosphate containing membranes are rigidified by lead, cobalt, and manganese whilst cadmium and nickel enhanced fluidity of membranes containing phosphatidylinositol-(4,5)-bisphosphate. Only cobalt induced liposome aggregation. All metals enhanced lipid clustering in phosphatidylinositol-(3,4,5)-triphosphate systems, cobalt in phosphatidylinositol-(4,5)-bisphosphate systems, while all metals showed limited changes in lateral film organization in phosphatidylinositol-(4)-phosphate matrices. These observed changes are relevant from the biophysical perspective as interference with the spatiotemporal formation of intricate domains composed of important signaling lipids may contribute to metal toxicity.
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9
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Mahata S, Bhattacharya A, Kumar JP, Mandal BB, Manivannan V. Naked-eye detection of Pd2+ ion using a highly selective fluorescent heterocyclic probe by “turn-off” response and in-vitro live cell imaging. J Photochem Photobiol A Chem 2020. [DOI: 10.1016/j.jphotochem.2020.112441] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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10
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Han K, Gericke A, Pastor RW. Characterization of Specific Ion Effects on PI(4,5)P 2 Clustering: Molecular Dynamics Simulations and Graph-Theoretic Analysis. J Phys Chem B 2020; 124:1183-1196. [PMID: 31994887 PMCID: PMC7461730 DOI: 10.1021/acs.jpcb.9b10951] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Numerous cellular functions mediated by phosphatidylinositol (4,5)-bisphosphate (PI(4,5)P2; PIP2) involve clustering of the lipid as well as colocalization with other lipids. Although the cation-mediated electrostatic interaction is regarded as the primary clustering mechanism, the ion-specific nature of the intermolecular network formation makes it challenging to characterize the clusters. Here we use all-atom molecular dynamics (MD) simulations of PIP2 monolayers and graph-theoretic analysis to gain insight into the phenomenon. MD simulations reveal that the intermolecular interactions preferentially occur between specific cations and phosphate groups (P1, P4, and P5) of the inositol headgroup with better-matched kosmotropic/chaotropic characters consistent with the law of matching water affinities (LMWA). Ca2+ is strongly attracted to P4/P5, while K+ preferentially binds to P1; Na+ interacts with both P4/P5 and P1. These specific interactions lead to the characteristic clustering patterns. Specificially, the size distributions and structures of PIP2 clusters generated by kosmotropic cations Ca2+ and Na+ are bimodal, with a combination of small and large clusters, while there is little clustering in the presence of only chaotropic K+; the largest clusters are obtained in systems with all three cations. The small-world network (a model with both local and long-range connections) best characterizes the clusters, followed by the random and the scale-free networks. More generally, the present results interpreted within the LMWA are consistent with the relative eukaryotic intracellular concentrations Ca2+ ≪ Na+ < Mg2+ < K+; that is, concentrations of Ca2+ and Na+ must be low to prevent damaging aggregation of lipids, DNA, RNA and phosphate-containing proteins.
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Affiliation(s)
- Kyungreem Han
- Laboratory of Computational Biology, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Arne Gericke
- Department of Chemistry and Biochemistry, Worcester Polytechnic Institute, Worcester, MA, 01609, USA
| | - Richard W. Pastor
- Laboratory of Computational Biology, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA
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11
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Graber ZT, Thomas J, Johnson E, Gericke A, Kooijman EE. Effect of H-Bond Donor Lipids on Phosphatidylinositol-3,4,5-Trisphosphate Ionization and Clustering. Biophys J 2019; 114:126-136. [PMID: 29320679 DOI: 10.1016/j.bpj.2017.10.029] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 10/10/2017] [Accepted: 10/13/2017] [Indexed: 12/29/2022] Open
Abstract
The phosphoinositide, phosphatidylinositol-3,4,5-trisphosphate (PI(3,4,5)P3), is a key signaling lipid in the inner leaflet of the cell plasma membrane, regulating diverse signaling pathways including cell growth and migration. In this study we investigate the impact of the hydrogen-bond donor lipids phosphatidylethanolamine (PE) and phosphatidylinositol (PI) on the charge and phase behavior of PI(3,4,5)P3. PE and PI can interact with PI(3,4,5)P3 through hydrogen-bond formation, leading to altered ionization behavior and charge distribution within the PI(3,4,5)P3 headgroup. We quantify the altered PI(3,4,5)P3 ionization behavior using a multistate ionization model to obtain micro-pKa values for the ionization of each phosphate group. The presence of PE leads to a decrease in the pKa values for the initial deprotonation of PI(3,4,5)P3, which describes the removal of the first proton of the three protons remaining at the phosphomonoester groups at pH 4.0. The decrease in these micro-pKa values thus leads to a higher charge at low pH. Additionally, the charge distribution changes lead to increased charge on the 3- and 5-phosphates. In the presence of PI, the final deprotonation of PI(3,4,5)P3 is delayed, leading to a lower charge at high pH. This is due to a combination of hydrogen-bond formation between PI and PI(3,4,5)P3, and increased surface charge due to the addition of the negatively charged PI. The interaction between PI and PI(3,4,5)P3 leads to the formation of PI and PI(3,4,5)P3-enriched domains within the membrane. These domains may have a critical impact on PI(3,4,5)P3-signaling. We also reevaluate results for all phosphatidylinositol bisphosphates as well as for PI(4,5)P2 in complex lipid mixtures with the multistate ionization model.
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Affiliation(s)
| | - Joseph Thomas
- Department of Biological Sciences, Kent State University, Kent, Ohio
| | - Emily Johnson
- Department of Biological Sciences, Kent State University, Kent, Ohio
| | - Arne Gericke
- Department of Chemistry and Biochemistry, Worcester Polytechnic Institute, Worcester, Massachusetts.
| | - Edgar E Kooijman
- Department of Biological Sciences, Kent State University, Kent, Ohio
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12
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Cebecauer M, Amaro M, Jurkiewicz P, Sarmento MJ, Šachl R, Cwiklik L, Hof M. Membrane Lipid Nanodomains. Chem Rev 2018; 118:11259-11297. [PMID: 30362705 DOI: 10.1021/acs.chemrev.8b00322] [Citation(s) in RCA: 138] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Lipid membranes can spontaneously organize their components into domains of different sizes and properties. The organization of membrane lipids into nanodomains might potentially play a role in vital functions of cells and organisms. Model membranes represent attractive systems to study lipid nanodomains, which cannot be directly addressed in living cells with the currently available methods. This review summarizes the knowledge on lipid nanodomains in model membranes and exposes how their specific character contrasts with large-scale phase separation. The overview on lipid nanodomains in membranes composed of diverse lipids (e.g., zwitterionic and anionic glycerophospholipids, ceramides, glycosphingolipids) and cholesterol aims to evidence the impact of chemical, electrostatic, and geometric properties of lipids on nanodomain formation. Furthermore, the effects of curvature, asymmetry, and ions on membrane nanodomains are shown to be highly relevant aspects that may also modulate lipid nanodomains in cellular membranes. Potential mechanisms responsible for the formation and dynamics of nanodomains are discussed with support from available theories and computational studies. A brief description of current fluorescence techniques and analytical tools that enabled progress in lipid nanodomain studies is also included. Further directions are proposed to successfully extend this research to cells.
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Affiliation(s)
- Marek Cebecauer
- J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences , Dolejškova 3 , 18223 Prague 8 , Czech Republic
| | - Mariana Amaro
- J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences , Dolejškova 3 , 18223 Prague 8 , Czech Republic
| | - Piotr Jurkiewicz
- J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences , Dolejškova 3 , 18223 Prague 8 , Czech Republic
| | - Maria João Sarmento
- J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences , Dolejškova 3 , 18223 Prague 8 , Czech Republic
| | - Radek Šachl
- J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences , Dolejškova 3 , 18223 Prague 8 , Czech Republic
| | - Lukasz Cwiklik
- J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences , Dolejškova 3 , 18223 Prague 8 , Czech Republic
| | - Martin Hof
- J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences , Dolejškova 3 , 18223 Prague 8 , Czech Republic
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13
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Han K, Venable RM, Bryant AM, Legacy CJ, Shen R, Li H, Roux B, Gericke A, Pastor RW. Graph-Theoretic Analysis of Monomethyl Phosphate Clustering in Ionic Solutions. J Phys Chem B 2018; 122:1484-1494. [PMID: 29293344 DOI: 10.1021/acs.jpcb.7b10730] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
All-atom molecular dynamics simulations combined with graph-theoretic analysis reveal that clustering of monomethyl phosphate dianion (MMP2-) is strongly influenced by the types and combinations of cations in the aqueous solution. Although Ca2+ promotes the formation of stable and large MMP2- clusters, K+ alone does not. Nonetheless, clusters are larger and their link lifetimes are longer in mixtures of K+ and Ca2+. This "synergistic" effect depends sensitively on the Lennard-Jones interaction parameters between Ca2+ and the phosphorus oxygen and correlates with the hydration of the clusters. The pronounced MMP2- clustering effect of Ca2+ in the presence of K+ is confirmed by Fourier transform infrared spectroscopy. The characterization of the cation-dependent clustering of MMP2- provides a starting point for understanding cation-dependent clustering of phosphoinositides in cell membranes.
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Affiliation(s)
- Kyungreem Han
- Laboratory of Computational Biology, National Heart, Lung, and Blood Institute, National Institutes of Health , Bethesda, Maryland 20892, United States
| | - Richard M Venable
- Laboratory of Computational Biology, National Heart, Lung, and Blood Institute, National Institutes of Health , Bethesda, Maryland 20892, United States
| | - Anne-Marie Bryant
- Department of Chemistry and Biochemistry, Worcester Polytechnic Institute , Worcester, Massachusetts 01609, United States
| | - Christopher J Legacy
- Department of Chemistry and Biochemistry, Worcester Polytechnic Institute , Worcester, Massachusetts 01609, United States
| | - Rong Shen
- Department of Biochemistry and Molecular Biology, The University of Chicago , Chicago, Illinois 60637, United States
| | - Hui Li
- Department of Biochemistry and Molecular Biology, The University of Chicago , Chicago, Illinois 60637, United States
| | - Benoît Roux
- Department of Biochemistry and Molecular Biology, The University of Chicago , Chicago, Illinois 60637, United States
| | - Arne Gericke
- Department of Chemistry and Biochemistry, Worcester Polytechnic Institute , Worcester, Massachusetts 01609, United States
| | - Richard W Pastor
- Laboratory of Computational Biology, National Heart, Lung, and Blood Institute, National Institutes of Health , Bethesda, Maryland 20892, United States
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14
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Graber ZT, Shi Z, Baumgart T. Cations induce shape remodeling of negatively charged phospholipid membranes. Phys Chem Chem Phys 2017; 19:15285-15295. [PMID: 28569910 PMCID: PMC5562360 DOI: 10.1039/c7cp00718c] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The divalent cation Ca2+ is a key component in many cell signaling and membrane trafficking pathways. Ca2+ signal transduction commonly occurs through interaction with protein partners. However, in this study we show a novel mechanism by which Ca2+ may impact membrane structure. We find an asymmetric concentration of Ca2+ across the membrane triggers deformation of membranes containing negatively charged lipids such as phosphatidylserine (PS) and phosphatidylinositol-4,5-bisphosphate (PI(4,5)P2). Membrane invaginations in vesicles were observed forming away from the leaflet with higher Ca2+ concentration, showing that Ca2+ induces negative curvature. We hypothesize that the negative curvature is produced by Ca2+-induced clustering of PS and PI(4,5)P2. In support of this notion, we find that Ca2+-induced membrane deformation is stronger for membranes containing PI(4,5)P2, which is known to more readily cluster in the presence of Ca2+. The observed Ca2+-induced membrane deformation is strongly influenced by Na+ ions. A high symmetric [Na+] across the membrane reduces Ca2+ binding by electrostatic shielding, inhibiting Ca2+-induced membrane deformation. An asymmetric [Na+] across the membrane, however, can either oppose or support Ca2+-induced deformation, depending on the direction of the gradient in [Na+]. At a sufficiently high asymmetric Na+ concentration it can impact membrane structure in the absence of Ca2+. We propose that Ca2+ works in concert with curvature generating proteins to modulate membrane curvature and shape transitions. This novel structural impact of Ca2+ could be important for Ca2+-dependent cellular processes that involve the creation of membrane curvature, including exocytosis, invadopodia, and cell motility.
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Affiliation(s)
- Z T Graber
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA, USA.
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15
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Bilkova E, Pleskot R, Rissanen S, Sun S, Czogalla A, Cwiklik L, Róg T, Vattulainen I, Cremer PS, Jungwirth P, Coskun Ü. Calcium Directly Regulates Phosphatidylinositol 4,5-Bisphosphate Headgroup Conformation and Recognition. J Am Chem Soc 2017; 139:4019-4024. [PMID: 28177616 PMCID: PMC5364432 DOI: 10.1021/jacs.6b11760] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The orchestrated recognition of phosphoinositides and concomitant intracellular release of Ca2+ is pivotal to almost every aspect of cellular processes, including membrane homeostasis, cell division and growth, vesicle trafficking, as well as secretion. Although Ca2+ is known to directly impact phosphoinositide clustering, little is known about the molecular basis for this or its significance in cellular signaling. Here, we study the direct interaction of Ca2+ with phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2), the main lipid marker of the plasma membrane. Electrokinetic potential measurements of PI(4,5)P2 containing liposomes reveal that Ca2+ as well as Mg2+ reduce the zeta potential of liposomes to nearly background levels of pure phosphatidylcholine membranes. Strikingly, lipid recognition by the default PI(4,5)P2 lipid sensor, phospholipase C delta 1 pleckstrin homology domain (PLC δ1-PH), is completely inhibited in the presence of Ca2+, while Mg2+ has no effect with 100 nm liposomes and modest effect with giant unilamellar vesicles. Consistent with biochemical data, vibrational sum frequency spectroscopy and atomistic molecular dynamics simulations reveal how Ca2+ binding to the PI(4,5)P2 headgroup and carbonyl regions leads to confined lipid headgroup tilting and conformational rearrangements. We rationalize these findings by the ability of calcium to block a highly specific interaction between PLC δ1-PH and PI(4,5)P2, encoded within the conformational properties of the lipid itself. Our studies demonstrate the possibility that switchable phosphoinositide conformational states can serve as lipid recognition and controlled cell signaling mechanisms.
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Affiliation(s)
- Eva Bilkova
- Paul Langerhans Institute Dresden of the Helmholtz Zentrum München at the University Hospital and Faculty of Medicine Carl Gustav Carus of TU Dresden, Technische Universität Dresden , Fetscher Strasse 74, 01307 Dresden, Germany.,German Center for Diabetes Research (DZD e.V.) , Ingolstädter Landstraße 1, 85764 Neuherberg, Germany
| | - Roman Pleskot
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic , Flemingovo náměstí 2, 16610 Prague 6, Czech Republic.,Institute of Experimental Botany, Academy of Sciences of the Czech Republic , v.v.i., Rozvojová 263, 16502 Prague 6, Czech Republic
| | - Sami Rissanen
- Department of Physics, Tampere University of Technology , P.O. Box 692, FI-33101 Tampere, Finland
| | | | - Aleksander Czogalla
- Paul Langerhans Institute Dresden of the Helmholtz Zentrum München at the University Hospital and Faculty of Medicine Carl Gustav Carus of TU Dresden, Technische Universität Dresden , Fetscher Strasse 74, 01307 Dresden, Germany.,Laboratory of Cytobiochemistry, Faculty of Biotechnology, University of Wrocław , Joliot-Curie 14a, 50-383 Wrocław, Poland
| | - Lukasz Cwiklik
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic , Flemingovo náměstí 2, 16610 Prague 6, Czech Republic.,J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic , v.v.i., Dolejskova 3, 18223 Prague 8, Czech Republic
| | - Tomasz Róg
- Department of Physics, Tampere University of Technology , P.O. Box 692, FI-33101 Tampere, Finland.,Department of Physics, University of Helsinki , P.O. Box 64, FI-00014, Helsinki, Finland
| | - Ilpo Vattulainen
- Department of Physics, Tampere University of Technology , P.O. Box 692, FI-33101 Tampere, Finland.,Department of Physics, University of Helsinki , P.O. Box 64, FI-00014, Helsinki, Finland.,MEMPHYS- Center for Biomembrane Physics, University of Southern Denmark , DK-5230 Odense, Denmark
| | | | - Pavel Jungwirth
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic , Flemingovo náměstí 2, 16610 Prague 6, Czech Republic.,Department of Physics, Tampere University of Technology , P.O. Box 692, FI-33101 Tampere, Finland
| | - Ünal Coskun
- Paul Langerhans Institute Dresden of the Helmholtz Zentrum München at the University Hospital and Faculty of Medicine Carl Gustav Carus of TU Dresden, Technische Universität Dresden , Fetscher Strasse 74, 01307 Dresden, Germany.,German Center for Diabetes Research (DZD e.V.) , Ingolstädter Landstraße 1, 85764 Neuherberg, Germany
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16
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Gong Z, Kerr D, Hwang HL, Henderson JM, Suwatthee T, Slaw BR, Cao KD, Lin B, Bu W, Lee KYC. Quantitative analysis of total reflection X-ray fluorescence from finely layered structures using XeRay. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2017; 88:033112. [PMID: 28372410 DOI: 10.1063/1.4978654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Total reflection x-ray fluorescence (TXRF) is a widely applicable experimental technique for studying chemical element distributions across finely layered structures at extremely high sensitivity. To promote and facilitate scientific discovery using TXRF, we developed a MATLAB-based software package with a graphical user interface, named XeRay, for quick, accurate, and intuitive data analysis. XeRay lets the user model any layered system, each layer with its independent chemical composition and thickness, and enables fine-tuned data fitting. The accuracy of XeRay has been tested in the analysis of TXRF data from both air/liquid interface and liquid/liquid interfacial studies and has been compared to literature results. In an air/liquid interface study, Ca2+ sequestration was measured at a Langmuir monolayer of 1-stearoyl-2-oleoyl-sn-glycero-3-phosphatidic acid (SOPA) on a buffer solution of 1 mM CaCl2 at pH 7.5. Data analysis with XeRay reveals that each 1 nm2 of interfacial area contains 2.38 ± 0.06 Ca2+ ions, which corresponds to a 1:1 ratio between SOPA headgroups and Ca2+ ions, consistent with several earlier reports. For the liquid/liquid interface study of Sr2+ enrichment at the dodecane/surfactant/water interface, analysis using XeRay gives a surface enrichment of Sr2+ at 68-5+6 Å2 per ion, consistent with the result published for the same dataset.
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Affiliation(s)
- Zhiliang Gong
- James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA
| | - Daniel Kerr
- Program in the Biophysical Sciences, Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois 60637, USA
| | - Hyeondo Luke Hwang
- James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA
| | - J Michael Henderson
- James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA
| | - Tiffany Suwatthee
- The College, The University of Chicago, Chicago, Illinois 60637, USA
| | - Benjamin R Slaw
- James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA
| | - Kathleen D Cao
- James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA
| | - Binhua Lin
- James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA
| | - Wei Bu
- Center for Advanced Radiation Sources, The University of Chicago, Chicago, Illinois 60637, USA
| | - Ka Yee C Lee
- James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA
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17
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Wang W, Zhang H, Feng S, San Emeterio J, Mallapragada S, Vaknin D. Iron Ion and Iron Hydroxide Adsorption to Charge-Neutral Phosphatidylcholine Templates. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:7664-7670. [PMID: 27409514 DOI: 10.1021/acs.langmuir.6b01851] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Surface-sensitive X-ray scattering and spectroscopy techniques reveal significant adsorption of iron ions and iron-hydroxide (Fe(III)) complexes to a charge-neutral zwitterionic template of phosphatidylcholine (PC). The PC template is formed by a Langmuir monolayer of dipalmitoyl-PC (DPPC) that is spread on the surface of 2 to 40 μM FeCl3 solutions at physiological levels of KCl (100 mM). At 40 μM of Fe(III) as many as ∼3 iron atoms are associated with each PC group. Grazing incidence X-ray diffraction measurements indicate a significant disruption in the in-plane ordering of DPPC molecules upon iron adsorption. The binding of iron-hydroxide complexes to a neutral PC surface is yet another example of nonelectrostatic, presumably covalent bonding to a charge-neutral organic template. The strong binding and the disruption of in-plane lipid structure has biological implications on the integrity of PC-derived lipid membranes, including those based on sphingomyelin.
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Affiliation(s)
- Wenjie Wang
- Division of Materials Sciences and Engineering, Ames Laboratory, USDOE , Ames, Iowa 50011, United States
| | - Honghu Zhang
- Ames Laboratory and Department of Materials Science and Engineering, Iowa State University , Ames, Iowa 50011, United States
| | - Shuren Feng
- Ames Laboratory and Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University , Ames, Iowa 50011, United States
| | - Josue San Emeterio
- Division of Materials Sciences and Engineering, Ames Laboratory, USDOE , Ames, Iowa 50011, United States
| | - Surya Mallapragada
- Ames Laboratory and Department of Chemical and Biological Engineering, Iowa State University , Ames, Iowa 50011, United States
| | - David Vaknin
- Ames Laboratory and Department of Physics and Astronomy, Iowa State University , Ames, Iowa 50011, United States
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