1
|
Stochasticity and positive feedback enable enzyme kinetics at the membrane to sense reaction size. Proc Natl Acad Sci U S A 2021; 118:2103626118. [PMID: 34789575 PMCID: PMC8617498 DOI: 10.1073/pnas.2103626118] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/10/2021] [Indexed: 12/27/2022] Open
Abstract
Cellular membranes span a wide range of spatial dimensions, from the plasma membrane with a scale of microns to vesicles on the nanometer scale. The work presented here identifies a molecular mechanism, based on common features of cellular signaling enzymes, that causes the average enzymatic catalytic rate to exhibit reaction size dependency. This effect stems from stochastic variation, but the final results can be essentially deterministic. In competitive enzymatic reaction cycles, the final product can depend on the size of the reaction system. The simplicity of the mechanism suggests that size-dependent reaction rates may be widespread among signaling enzymes and thus enable reaction size to be an important factor in signal regulation at the membrane. Here, we present detailed kinetic analyses of a panel of soluble lipid kinases and phosphatases, as well as Ras activating proteins, acting on their respective membrane surface substrates. The results reveal that the mean catalytic rate of such interfacial enzymes can exhibit a strong dependence on the size of the reaction system—in this case membrane area. Experimental measurements and kinetic modeling reveal how stochastic effects stemming from low molecular copy numbers of the enzymes alter reaction kinetics based on mechanistic characteristics of the enzyme, such as positive feedback. For the competitive enzymatic cycles studied here, the final product—consisting of a specific lipid composition or Ras activity state—depends on the size of the reaction system. Furthermore, we demonstrate how these reaction size dependencies can be controlled by engineering feedback mechanisms into the enzymes.
Collapse
|
2
|
Tremel S, Ohashi Y, Morado DR, Bertram J, Perisic O, Brandt LTL, von Wrisberg MK, Chen ZA, Maslen SL, Kovtun O, Skehel M, Rappsilber J, Lang K, Munro S, Briggs JAG, Williams RL. Structural basis for VPS34 kinase activation by Rab1 and Rab5 on membranes. Nat Commun 2021; 12:1564. [PMID: 33692360 PMCID: PMC7946940 DOI: 10.1038/s41467-021-21695-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 02/01/2021] [Indexed: 02/07/2023] Open
Abstract
The lipid phosphatidylinositol-3-phosphate (PI3P) is a regulator of two fundamental but distinct cellular processes, endocytosis and autophagy, so its generation needs to be under precise temporal and spatial control. PI3P is generated by two complexes that both contain the lipid kinase VPS34: complex II on endosomes (VPS34/VPS15/Beclin 1/UVRAG), and complex I on autophagosomes (VPS34/VPS15/Beclin 1/ATG14L). The endosomal GTPase Rab5 binds complex II, but the mechanism of VPS34 activation by Rab5 has remained elusive, and no GTPase is known to bind complex I. Here we show that Rab5a–GTP recruits endocytic complex II to membranes and activates it by binding between the VPS34 C2 and VPS15 WD40 domains. Electron cryotomography of complex II on Rab5a-decorated vesicles shows that the VPS34 kinase domain is released from inhibition by VPS15 and hovers over the lipid bilayer, poised for catalysis. We also show that the GTPase Rab1a, which is known to be involved in autophagy, recruits and activates the autophagy-specific complex I, but not complex II. Both Rabs bind to the same VPS34 interface but in a manner unique for each. These findings reveal how VPS34 complexes are activated on membranes by specific Rab GTPases and how they are recruited to unique cellular locations. The phosphatidylinositol-3-phosphate (PI3P) is generated by the lipid kinase VPS34, in the context of VPS34 complex I on autophagosomes or complex II on endosomes. Biochemical and structural analyses provide insights into the mechanism of both VPS34 complexes recruitment to and activation on membranes by specific Rab GTPases.
Collapse
Affiliation(s)
| | - Yohei Ohashi
- MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Dustin R Morado
- MRC Laboratory of Molecular Biology, Cambridge, UK.,Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Solna, Sweden
| | | | - Olga Perisic
- MRC Laboratory of Molecular Biology, Cambridge, UK
| | | | - Marie-Kristin von Wrisberg
- Center for Integrated Protein Science Munich (CIPSM), Department of Chemistry, Lab for Synthetic Biochemistry, Technical University of Munich, Institute for Advanced Study, TUM-IAS, Garching, Germany
| | - Zhuo A Chen
- Bioanalytics, Institute of Biotechnology, Technische Universität Berlin, Berlin, Germany
| | | | | | - Mark Skehel
- MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Juri Rappsilber
- Bioanalytics, Institute of Biotechnology, Technische Universität Berlin, Berlin, Germany.,Wellcome Centre for Cell Biology, University of Edinburgh, Edinburgh, UK
| | - Kathrin Lang
- Center for Integrated Protein Science Munich (CIPSM), Department of Chemistry, Lab for Synthetic Biochemistry, Technical University of Munich, Institute for Advanced Study, TUM-IAS, Garching, Germany
| | - Sean Munro
- MRC Laboratory of Molecular Biology, Cambridge, UK.
| | | | | |
Collapse
|
3
|
Abstract
Phosphatidate phosphatase (PAP) catalyzes the penultimate step in the synthesis of triacylglycerol and regulates the synthesis of membrane phospholipids. There is much interest in this enzyme because it controls the cellular levels of its substrate, phosphatidate (PA), and product, DAG; defects in the metabolism of these lipid intermediates are the basis for lipid-based diseases such as obesity, lipodystrophy, and inflammation. The measurement of PAP activity is required for studies aimed at understanding its mechanisms of action, how it is regulated, and for screening its activators and/or inhibitors. Enzyme activity is determined through the use of radioactive and nonradioactive assays that measure the product, DAG, or Pi However, sensitivity and ease of use are variable across these methods. This review summarizes approaches to synthesize radioactive PA, to analyze radioactive and nonradioactive products, DAG and Pi, and discusses the advantages and disadvantages of each PAP assay.
Collapse
Affiliation(s)
- Prabuddha Dey
- Department of Food Science and the Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, NJ, USA
| | - Gil-Soo Han
- Department of Food Science and the Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, NJ, USA
| | - George M Carman
- Department of Food Science and the Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, NJ, USA.
| |
Collapse
|
4
|
Kwiatek JM, Carman GM. Yeast phosphatidic acid phosphatase Pah1 hops and scoots along the membrane phospholipid bilayer. J Lipid Res 2020; 61:1232-1243. [PMID: 32540926 DOI: 10.1194/jlr.ra120000937] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 06/09/2020] [Indexed: 01/01/2023] Open
Abstract
PA phosphatase, encoded by PAH1 in the yeast Saccharomyces cerevisiae, catalyzes the Mg2+-dependent dephosphorylation of PA, producing DAG at the nuclear/ER membrane. This enzyme plays a major role in triacylglycerol synthesis and in the regulation of phospholipid synthesis. As an interfacial enzyme, PA phosphatase interacts with the membrane surface, binds its substrate, and catalyzes its reaction. The Triton X-100/PA-mixed micellar system has been utilized to examine the activity and regulation of yeast PA phosphatase. This system, however, does not resemble the in vivo environment of the membrane phospholipid bilayer. We developed an assay system that mimics the nuclear/ER membrane to assess PA phosphatase activity. PA was incorporated into unilamellar phospholipid vesicles (liposomes) composed of the major nuclear/ER membrane phospholipids, PC, PE, PI, and PS. We optimized this system to support enzyme-liposome interactions and to afford activity that is greater than that obtained with the aforementioned detergent system. Activity was regulated by phospholipid composition, whereas the enzyme's interaction with liposomes was insensitive to composition. Greater activity was attained with large (≥100 nm) versus small (50 nm) vesicles. The fatty-acyl moiety of PA had no effect on this activity. PA phosphatase activity was dependent on the bulk (hopping mode) and surface (scooting mode) concentrations of PA, suggesting a mechanism by which the enzyme operates along the nuclear/ER membrane in vivo.
Collapse
Affiliation(s)
- Joanna M Kwiatek
- Department of Food Science and Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, NJ 08901
| | - George M Carman
- Department of Food Science and Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, NJ 08901
| |
Collapse
|
5
|
Cherif S, Carrière F, Sayari A, Fendri A. Studies of crab digestive phospholipase acting on phospholipid monolayers: Activation by temperature. Int J Biol Macromol 2020; 142:705-711. [PMID: 31622722 DOI: 10.1016/j.ijbiomac.2019.10.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 09/19/2019] [Accepted: 10/01/2019] [Indexed: 11/26/2022]
Abstract
Secreted phospholipases A2 (sPLA2) are water-soluble lipolytic enzymes that act at the interface of organized lipid substrates, where the catalytic step is coupled to various interfacial phenomena as enzyme penetration, solubilisation of reaction products, lateral packing and loss of mechanical stability of organized assemblies of phospholipid molecule, among others. Using the monomolecular film technique, we compared the interfacial properties of crab digestive sPLA2 (CDPL) with those of the porcine pancreatic one (PPPL). A kinetic study on the surface pressure dependency of the two sPLA2 was performed using monomolecular films of three different substrates: di C12-PC (1.2-dilauroyl-sn-glycerol-3-phosphocholine); di C12-PG (1.2-dilauroyl-sn-glycerol-3-phosphoglycerol) and di C12-PE (1.2-dilauroyl-sn-glycerol-3-phosphoethanolamine). The use of a substrate in monolayer state, during the catalytic reactions, allows us to monitor the effect of several physicochemical parameters by altering the "quality of interface". The effect of temperature on the hydrolysis rate of these substrates was also checked. Our results show that activities of both phospholipases were affected by the variation of the subphase temperature. CDPL was irreversibly inactivated by p-bromo-phenacyl bromide, the specific inhibitor of sPLA2. The hyperbolic catalytic behaviour observed was coherent with hopping mode of action, one of the two characteristic mechanisms of interfacial catalysis of sPLA2.
Collapse
Affiliation(s)
- Slim Cherif
- Laboratory of Biochemistry and Enzymatic Engineering of Lipases, ENIS, Sfax, Tunisia
| | - Frederic Carrière
- Aix Marseille University, CNRS, BIP, UMR7281, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 9, France
| | - Adel Sayari
- Laboratory of Biochemistry and Enzymatic Engineering of Lipases, ENIS, Sfax, Tunisia
| | - Ahmed Fendri
- Laboratory of Biochemistry and Enzymatic Engineering of Lipases, ENIS, Sfax, Tunisia.
| |
Collapse
|
6
|
Roberts MF, Khan HM, Goldstein R, Reuter N, Gershenson A. Search and Subvert: Minimalist Bacterial Phosphatidylinositol-Specific Phospholipase C Enzymes. Chem Rev 2018; 118:8435-8473. [DOI: 10.1021/acs.chemrev.8b00208] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Mary F. Roberts
- Department of Chemistry, Boston College, Chestnut Hill, Massachusetts 02467, United States
| | | | - Rebecca Goldstein
- Department of Chemistry, Boston College, Chestnut Hill, Massachusetts 02467, United States
| | | | - Anne Gershenson
- Department of Biochemistry and Molecular Biology, University of Massachusetts Amherst, Amherst, Massachusetts 01003, United States
| |
Collapse
|
7
|
Mateos-Diaz E, Sutto-Ortiz P, Sahaka M, Byrne D, Gaussier H, Carrière F. IR spectroscopy analysis of pancreatic lipase-related protein 2 interaction with phospholipids: 2. Discriminative recognition of various micellar systems and characterization of PLRP2-DPPC-bile salt complexes. Chem Phys Lipids 2017; 211:66-76. [PMID: 29155085 DOI: 10.1016/j.chemphyslip.2017.11.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Revised: 11/14/2017] [Accepted: 11/15/2017] [Indexed: 12/14/2022]
Abstract
The interaction of pancreatic lipase-related protein 2 (PLRP2) with various micelles containing phospholipids was investigated using pHstat enzyme activity measurements, differential light scattering, size exclusion chromatography (SEC) and transmission IR spectroscopy. Various micelles of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and lysophosphatidylcholine were prepared with either bile salts (sodium taurodeoxycholate or glycodeoxycholate) or Triton X-100, which are substrate-dispersing agents commonly used for measuring phospholipase activities. PLRP2 displayed a high activity on all phospholipid-bile salt micelles, but was totally inactive on phospholipid-Triton X-100 micelles. These findings clearly differentiate PLRP2 from secreted pancreatic phospholipase A2 which is highly active on both types of micelles. Using an inactive variant of PLRP2, SEC experiments allowed identifying two populations of PLRP2-DPPC-bile salt complexes corresponding to a high molecular weight 1:1 PLRP2-micelle association and to a low molecular weight association of PLRP2 with few monomers of DPPC/bile salts. IR spectroscopy analysis showed how DPPC-bile salt micelles differ from DPPC-Triton X-100 micelles by a higher fluidity of acyl chains and higher hydration/H-bonding of the interfacial carbonyl region. The presence of bile salts allowed observing changes in the IR spectrum of DPPC upon addition of PLRP2 (higher rigidity of acyl chains, dehydration of the interfacial carbonyl region), while no change was observed with Triton X-100. The differences between these surfactants and their impact on substrate recognition by PLRP2 are discussed, as well as the mechanism by which high and low molecular weight PLRP2-DPPC-bile salt complexes may be involved in the overall process of DPPC hydrolysis.
Collapse
Affiliation(s)
- Eduardo Mateos-Diaz
- Aix-Marseille Université, CNRS, UMR7282 Enzymologie Interfaciale et Physiologie de la Lipolyse, Marseille, France
| | - Priscila Sutto-Ortiz
- Aix-Marseille Université, CNRS, UMR7282 Enzymologie Interfaciale et Physiologie de la Lipolyse, Marseille, France; Biotecnología Industrial, Centro de Investigación y Asistencia en Tecnología y Diseño del Estado de Jalisco A.C. (CIATEJ), Zapopan, Jalisco, México
| | - Moulay Sahaka
- Aix-Marseille Université, CNRS, UMR7282 Enzymologie Interfaciale et Physiologie de la Lipolyse, Marseille, France
| | - Deborah Byrne
- Aix-Marseille Université, CNRS, FR3479 Institut de Microbiologie de la Méditerranée, Marseille, France
| | - Hélène Gaussier
- Aix-Marseille Université, CNRS, UMR7282 Enzymologie Interfaciale et Physiologie de la Lipolyse, Marseille, France
| | - Frédéric Carrière
- Aix-Marseille Université, CNRS, UMR7282 Enzymologie Interfaciale et Physiologie de la Lipolyse, Marseille, France.
| |
Collapse
|
8
|
Petryayeva E, Jeen T, Algar WR. Optimization and Changes in the Mode of Proteolytic Turnover of Quantum Dot-Peptide Substrate Conjugates through Moderation of Interfacial Adsorption. ACS APPLIED MATERIALS & INTERFACES 2017; 9:30359-30372. [PMID: 28846381 DOI: 10.1021/acsami.7b07519] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Enzymes have many important roles in biology and industry, and proteases are one of the most important classes of enzymes. Semiconductor quantum dots (QDs) are attractive materials for developing protease activity probes because of their advantageous physical and optical properties; however, interactions between a protease and a QD conjugated with its substrate can affect the turnover of that substrate. Here, we study the turnover of multivalent QD-peptide substrate conjugates as a function of multiple parameters: (i) the ligand coating on the QD, including dihydrolipoic acid (DHLA), glutathione (GSH), DHLA-poly(ethylene glycol) (DHLA-PEG), and DHLA-zwitterionic sulfobetaine (DHLA-SB); (ii) the identity of the protease, including trypsin, thrombin, and plasmin; and (iii) the number of substrate and nonsubstrate biomacromolecules conjugated per QD. We show that limiting protease adsorption on QDs is critical for optimizing the turnover of conjugated peptide substrates. Protease adsorption is inhibitory, and very strong adsorption leads to an apparent "scooting" mode of activity with limited turnover. In contrast, with weaker adsorption, enhancements in the turnover rate likely result from a "hopping" mode of activity. The putative hopping mode is thought to feature processive turnover of all substrates in multivalent conjugates with a rate-limiting step of diffusion between individual conjugates, and the magnitude of such enhancements increases with decreases in adsorption. Although it was possible to passivate DHLA- and GSH-coated QDs with high densities of conjugated biomacromolecules, the most effective strategy for reducing adsorption was the substitution of these ligands. Whereas passivation incrementally increased turnover, DHLA-PEG and DHLA-SB ligands converted the mode of turnover with plasmin from scooting to hopping and the DHLA-SB enhanced the turnover rates with thrombin and trypsin by approximately an order of magnitude relative to GSH ligands. The new insights from the broad scope of this study provide an important framework for designing optimized QD conjugates as probes and sensors for enzyme activity.
Collapse
Affiliation(s)
- Eleonora Petryayeva
- Department of Chemistry, University of British Columbia , 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
| | - Tiffany Jeen
- Department of Chemistry, University of British Columbia , 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
| | - W Russ Algar
- Department of Chemistry, University of British Columbia , 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
| |
Collapse
|
9
|
Berezhkovskii AM, Dagdug L, Bezrukov SM. Bulk-mediated surface transport in the presence of bias. J Chem Phys 2017; 147:014103. [PMID: 28688439 PMCID: PMC5500123 DOI: 10.1063/1.4991730] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Accepted: 06/21/2017] [Indexed: 12/22/2022] Open
Abstract
Surface transport, when the particle is allowed to leave the surface, travel in the bulk for some time, and then return to the surface, is referred to as bulk-mediated surface transport. Recently, we proposed a formalism that significantly simplifies analysis of bulk-mediated surface diffusion [A. M. Berezhkovskii, L. Dagdug, and S. M. Bezrukov, J. Chem. Phys. 143, 084103 (2015)]. Here this formalism is extended to bulk-mediated surface transport in the presence of bias, i.e., when the particle has arbitrary drift velocities on the surface and in the bulk. A key advantage of our approach is that the transport problem reduces to that of a two-state problem of the particle transitions between the surface and the bulk. The latter can be solved with relative ease. The formalism is used to find the Laplace transforms of the first two moments of the particle displacement over the surface in time t at arbitrary values of the particle drift velocities and diffusivities on the surface and in the bulk. This allows us to analyze in detail the time dependence of the effective drift velocity of the particle on the surface, which can be highly nontrivial.
Collapse
Affiliation(s)
- Alexander M Berezhkovskii
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Leonardo Dagdug
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Sergey M Bezrukov
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
| |
Collapse
|
10
|
Preface. Methods Enzymol 2017; 583:xv-xix. [DOI: 10.1016/s0076-6879(16)30456-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
|
11
|
Preface. Methods Enzymol 2017; 584:xv-xix. [DOI: 10.1016/s0076-6879(16)30469-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
|
12
|
Bender G, Schexnaydre EE, Murphy RC, Uhlson C, Newcomer ME. Membrane-dependent Activities of Human 15-LOX-2 and Its Murine Counterpart: IMPLICATIONS FOR MURINE MODELS OF ATHEROSCLEROSIS. J Biol Chem 2016; 291:19413-24. [PMID: 27435673 DOI: 10.1074/jbc.m116.741454] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Indexed: 12/17/2022] Open
Abstract
The enzyme encoded by the ALOX15B gene has been linked to the development of atherosclerotic plaques in humans and in a mouse model of hypercholesterolemia. In vitro, these enzymes, which share 78% sequence identity, generate distinct products from their substrate arachidonic acid: the human enzyme, a 15-S-hydroperoxy product; and the murine enzyme, an 8-S-product. We probed the activities of these enzymes with nanodiscs as membrane mimics to determine whether they can access substrate esterified in a bilayer and characterized their activities at the membrane interface. We observed that both enzymes transform phospholipid-esterified arachidonic acid to a 15-S-product. Moreover, when expressed in transfected HEK cells, both enzymes result in significant increases in the amounts of 15-hydroxyderivatives of eicosanoids detected. In addition, we show that 15-LOX-2 is distributed at the plasma membrane when the HEK293 cells are stimulated by the addition Ca(2+) ionophore and that cellular localization is dependent upon the presence of a putative membrane insertion loop. We also report that sequence differences between the human and mouse enzymes in this loop appear to confer distinct mechanisms of enzyme-membrane interaction for the homologues.
Collapse
Affiliation(s)
- Gunes Bender
- From the Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana 70803 and
| | - Erin E Schexnaydre
- From the Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana 70803 and
| | - Robert C Murphy
- the Department of Pharmacology, University of Colorado at Denver, Aurora, Colorado 80045
| | - Charis Uhlson
- the Department of Pharmacology, University of Colorado at Denver, Aurora, Colorado 80045
| | - Marcia E Newcomer
- From the Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana 70803 and
| |
Collapse
|
13
|
Tabaei SR, Guo F, Rutaganira FU, Vafaei S, Choong I, Shokat KM, Glenn JS, Cho NJ. Multistep Compositional Remodeling of Supported Lipid Membranes by Interfacially Active Phosphatidylinositol Kinases. Anal Chem 2016; 88:5042-5. [PMID: 27118725 PMCID: PMC5291064 DOI: 10.1021/acs.analchem.6b01293] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The multienzyme catalytic phosphorylation of phosphatidylinositol (PI) in a supported lipid membrane platform is demonstrated for the first time. One-step treatment with PI 4-kinase IIIβ (PI4Kβ) yielded PI 4-phosphate (PI4P), while a multistep enzymatic cascade of PI4Kβ followed by PIP 5-kinase produced PI-4,5-bisphosphate (PI(4,5)P2 or PIP2). By employing quartz crystal microbalance with dissipation monitoring, we were able to track membrane association of kinase enzymes for the first time as well as detect PI4P and PI(4,5)P2 generation based on subsequent antibody binding to the supported lipid bilayers. Pharmacologic inhibition of PI4Kβ by a small molecule inhibitor was also quantitatively assessed, yielding an EC50 value that agrees well with conventional biochemical readout. Taken together, the development of a PI-containing supported membrane platform coupled with surface-sensitive measurement techniques for kinase studies opens the door to exploring the rich biochemistry and pharmacological targeting of membrane-associated phosphoinositides.
Collapse
Affiliation(s)
- Seyed R. Tabaei
- School of Materials Science and Engineering and Centre for Biomimetic Sensor Science, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore
| | - Feng Guo
- Departments of Medicine, Division of Gastroenterology and Hepatology, and Microbiology & Immunology, Stanford University School of Medicine, Stanford, California 94305, United States
| | - Florentine U. Rutaganira
- Howard Hughes Medical Institute, Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, California 94158-2280, United States
| | - Setareh Vafaei
- School of Materials Science and Engineering and Centre for Biomimetic Sensor Science, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore
| | - Ingrid Choong
- Departments of Medicine, Division of Gastroenterology and Hepatology, and Microbiology & Immunology, Stanford University School of Medicine, Stanford, California 94305, United States
| | - Kevan M. Shokat
- Howard Hughes Medical Institute, Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, California 94158-2280, United States
| | - Jeffrey S. Glenn
- Departments of Medicine, Division of Gastroenterology and Hepatology, and Microbiology & Immunology, Stanford University School of Medicine, Stanford, California 94305, United States
- Palo Alto Veterans Administration Medical Center, Palo Alto, California 94304, United States
| | - Nam-Joon Cho
- School of Materials Science and Engineering and Centre for Biomimetic Sensor Science, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore
| |
Collapse
|
14
|
The intrinsically disordered tails of PTEN and PTEN-L have distinct roles in regulating substrate specificity and membrane activity. Biochem J 2015; 473:135-44. [PMID: 26527737 PMCID: PMC4700475 DOI: 10.1042/bj20150931] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Accepted: 11/02/2015] [Indexed: 11/17/2022]
Abstract
Phosphatase and tensin homologue deleted on chromosome 10 (PTEN) is a lipid and protein phosphatase, and both activities are necessary for its role as a tumour suppressor. PTEN activity is controlled by phosphorylation of its intrinsically disordered C-terminal tail. A recently discovered variant of PTEN, PTEN-long (PTEN-L), has a 173-residue N-terminal extension that causes PTEN-L to exhibit unique behaviour, such as movement from one cell to another. Using hydrogen/deuterium exchange mass spectrometry (HDX-MS) and biophysical assays, we show that both the N-terminal extension of PTEN-L and C-terminal tail of PTEN affect the phosphatase activity using unique mechanisms. Phosphorylation of six residues in the C-terminal tail of PTEN results in auto-inhibitory interactions with the phosphatase and C2 domains, effectively blocking both the active site and the membrane-binding interface of PTEN. Partially dephosphorylating PTEN on pThr(366)/pSer(370) results in sufficient exposure of the active site to allow a selective activation for soluble substrates. Using HDX-MS, we identified a membrane-binding element in the N-terminal extension of PTEN-L, termed the membrane-binding helix (MBH). The MBH radically alters the membrane binding mechanism of PTEN-L compared with PTEN, switching PTEN-L to a 'scooting' mode of catalysis from the 'hopping' mode that is characteristic of PTEN.
Collapse
|
15
|
Berezhkovskii AM, Dagdug L, Bezrukov SM. A new approach to the problem of bulk-mediated surface diffusion. J Chem Phys 2015; 143:084103. [PMID: 26328814 DOI: 10.1063/1.4928741] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
This paper is devoted to bulk-mediated surface diffusion of a particle which can diffuse both on a flat surface and in the bulk layer above the surface. It is assumed that the particle is on the surface initially (at t = 0) and at time t, while in between it may escape from the surface and come back any number of times. We propose a new approach to the problem, which reduces its solution to that of a two-state problem of the particle transitions between the surface and the bulk layer, focusing on the cumulative residence times spent by the particle in the two states. These times are random variables, the sum of which is equal to the total observation time t. The advantage of the proposed approach is that it allows for a simple exact analytical solution for the double Laplace transform of the conditional probability density of the cumulative residence time spent on the surface by the particle observed for time t. This solution is used to find the Laplace transform of the particle mean square displacement and to analyze the peculiarities of its time behavior over the entire range of time. We also establish a relation between the double Laplace transform of the conditional probability density and the Fourier-Laplace transform of the particle propagator over the surface. The proposed approach treats the cases of both finite and infinite bulk layer thicknesses (where bulk-mediated surface diffusion is normal and anomalous at asymptotically long times, respectively) on equal footing.
Collapse
Affiliation(s)
- Alexander M Berezhkovskii
- Program in Physical Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Leonardo Dagdug
- Program in Physical Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Sergey M Bezrukov
- Program in Physical Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
| |
Collapse
|
16
|
Damodaran S. Beyond the hydrophobic effect: Critical function of water at biological phase boundaries--A hypothesis. Adv Colloid Interface Sci 2015; 221:22-33. [PMID: 25888225 DOI: 10.1016/j.cis.2015.03.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Revised: 03/24/2015] [Accepted: 03/25/2015] [Indexed: 11/29/2022]
Abstract
Many life-sustaining processes in living cells occur at the membrane-water interface. The pertinent questions that need to be asked are what is the evolutionary reason for biology to choose the membrane-water interface as the site for performing and/or controlling crucial biological reactions and what is the key physical principle that is singular to the membrane-water interface that biology exploits for regulating metabolic processes in cells? In this review, a hypothesis is developed, which espouses that cells control activities of membrane-bound enzymes and receptor activated processes via manipulating the thermodynamic activity of water at the membrane-water interfacial region. In support of this hypothesis, first we establish that the surface pressure of a lipid monolayer is a direct measure of a reduction in the thermodynamic activity of interfacial water. Second, we show that the surface pressure-dependent activation/inactivation of interfacial enzymes is fundamentally related to their dependence on interfacial water activity. We extend this argument to infer that cells might manipulate activities of membrane-associated biological processes via manipulating the activity of interfacial water via localized compression or expansion of the interface. In this paper, we critically analyze literature data on mechano-activation of large pore ion channels in Escherichia coli spheroplasts and G-proteins in reconstituted lipid vesicles, and show that these pressure-induced activation processes are fundamentally and quantitatively related to changes in the thermodynamic state of interfacial water, caused by mechanical stretching of the bilayer.
Collapse
Affiliation(s)
- Srinivasan Damodaran
- University of Wisconsin-Madison, Department of Food Science, 1605 Linden Drive, Madison, WI 53706, United States.
| |
Collapse
|
17
|
Mariani ME, Madoery RR, Fidelio GD. Kinetic characterization, optimum conditions for catalysis and substrate preference of secretory phospholipase A2 from Glycine max in model membrane systems. Biochimie 2015; 108:48-58. [PMID: 25447147 DOI: 10.1016/j.biochi.2014.10.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Accepted: 10/21/2014] [Indexed: 10/24/2022]
Abstract
Two secretory phospholipase A2 (sPLA2s) from Glycine max, GmsPLA2-IXA-1 and GmsPLA2-XIB-2, have been purified as recombinant proteins and the activity was evaluated in order to obtain the optimum conditions for catalysis using mixed micelles and lipid monolayers as substrate. Both sPLA2s showed a maximum enzyme activity at pH 7 and a requirement of Ca(2+) in the micromolar range. These parameters were similar to those found for animal sPLA2s but a surprising optimum temperature for catalysis at 60 °C was observed. The effect of negative interfacial charges on the hydrolysis of organized substrates was evaluated through initial rate measurements using short chain phospholipids with different head groups. The enzymes showed subtle differences in the specificity for phospholipids with different head groups (DLPC, DLPG, DLPE, DLPA) in presence or absence of NaCl. Both recombinant enzymes showed lower activity toward anionic phospholipids and a preference for the zwitterionic ones. The values of the apparent kinetic parameters (Vmax and KM) demonstrated that these enzymes have more affinity for phosphatidylcholine compared with phosphatidylglycerol, in contrast with the results observed for pancreatic sPLA2. A hopping mode of catalysis was proposed for the action of these sPLA2 on mixed phospholipid/triton micelles. On the other hand, Langmuir-monolayers assays indicated an optimum lateral surface pressure for activity in between 13 and 16 mN/m for both recombinant enzymes.
Collapse
Affiliation(s)
- María Elisa Mariani
- Centro de Investigaciones en Química Biológica de Córdoba, (CIQUIBIC, UNC-CONICET), Departamento de Química Biológica, Facultad de Cs. Químicas, Universidad Nacional de Córdoba, Haya de la Torre y Medina Allende, Ciudad Universitaria, X5000HUA Córdoba, Argentina
| | - Ricardo Román Madoery
- Departamento de Fundamentación Biológica, Facultad de Ciencias Agropecuarias, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Gerardo Daniel Fidelio
- Centro de Investigaciones en Química Biológica de Córdoba, (CIQUIBIC, UNC-CONICET), Departamento de Química Biológica, Facultad de Cs. Químicas, Universidad Nacional de Córdoba, Haya de la Torre y Medina Allende, Ciudad Universitaria, X5000HUA Córdoba, Argentina.
| |
Collapse
|
18
|
Rabe M, Tabaei SR, Zetterberg H, Zhdanov VP, Höök F. Hydrolysis of a Lipid Membrane by Single Enzyme Molecules: Accurate Determination of Kinetic Parameters. Angew Chem Int Ed Engl 2014; 54:1022-6. [DOI: 10.1002/anie.201409603] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Indexed: 01/08/2023]
|
19
|
Rabe M, Tabaei SR, Zetterberg H, Zhdanov VP, Höök F. Hydrolysis of a Lipid Membrane by Single Enzyme Molecules: Accurate Determination of Kinetic Parameters. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201409603] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
|
20
|
Soderquist RS, Danilov AV, Eastman A. Gossypol increases expression of the pro-apoptotic BH3-only protein NOXA through a novel mechanism involving phospholipase A2, cytoplasmic calcium, and endoplasmic reticulum stress. J Biol Chem 2014; 289:16190-9. [PMID: 24778183 DOI: 10.1074/jbc.m114.562900] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Gossypol is a putative BH3 mimetic proposed to inhibit BCL2 and BCLXL based on cell-free assays. We demonstrated previously that gossypol failed to directly inhibit BCL2 in cells or induce apoptosis in chronic lymphocytic leukemia (CLL) cells or platelets, which require BCL2 or BCLXL, respectively, for survival. Here, we demonstrate that gossypol rapidly increased activity of phospholipase A2 (PLA2), which led to an increase in cytoplasmic calcium, endoplasmic reticulum (ER) stress, and up-regulation of the BH3-only protein NOXA. Pretreatment with the PLA2 inhibitor, aristolochic acid, abrogated the increase in calcium, ER stress, and NOXA. Calcium chelation also abrogated the gossypol-induced increase in calcium, ER stress, and NOXA, but not the increase in PLA2 activity, indicating that PLA2 is upstream of these events. In addition, incubating cells with the two products of PLA2 (lysophosphatidic acid and arachidonic acid) mimicked treatment with gossypol. NOXA is a pro-apoptotic protein that functions by binding the BCL2 family proteins MCL1 and BFL1. The BCL2 inhibitor ABT-199 is currently in clinical trials for CLL. Resistance to ABT-199 can occur from up-regulation of other BCL2 family proteins, and this resistance can be mimicked by culturing CLL cells on CD154(+) stroma cells. We report here that AT-101, a derivative of gossypol in clinical trials, overcomes stroma-mediated resistance to ABT-199 in primary CLL cells, suggesting that a combination of these drugs may be efficacious in the clinic.
Collapse
Affiliation(s)
| | - Alexey V Danilov
- Medicine and the Norris Cotton Cancer Center, Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire 03756
| | - Alan Eastman
- From the Departments of Pharmacology and Toxicology and the Norris Cotton Cancer Center, Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire 03756
| |
Collapse
|
21
|
Stahelin RV. A new model of interfacial kinetics for phospholipases. Biophys J 2014; 105:1-2. [PMID: 23823217 DOI: 10.1016/j.bpj.2013.03.044] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Revised: 03/01/2013] [Accepted: 03/07/2013] [Indexed: 01/09/2023] Open
Affiliation(s)
- Robert V Stahelin
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine-South Bend, South Bend, Indiana, USA.
| |
Collapse
|
22
|
Majd S, Yusko EC, Yang J, Sept D, Mayer M. A model for the interfacial kinetics of phospholipase D activity on long-chain lipids. Biophys J 2014; 105:146-53. [PMID: 23823233 DOI: 10.1016/j.bpj.2013.05.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Revised: 05/02/2013] [Accepted: 05/06/2013] [Indexed: 11/26/2022] Open
Abstract
The membrane-active enzyme phospholipase D (PLD) catalyzes the hydrolysis of the phosphodiester bond in phospholipids and plays a critical role in cell signaling. This catalytic reaction proceeds on lipid-water interfaces and is an example of heterogeneous catalysis in biology. Recently we showed that planar lipid bilayers, a previously unexplored model membrane for these kinetic studies, can be used for monitoring interfacial catalytic reactions under well-defined experimental conditions with chemical and electrical access to both sides of the lipid membrane. Employing an assay that relies on the conductance of the pore-forming peptide gramicidin A to monitor PLD activity, the work presented here reveals the kinetics of hydrolysis of long-chain phosphatidylcholine lipids in situ. We have developed an extension of a basic kinetic model for interfacial catalysis that includes product activation and substrate depletion. This model describes the kinetic behavior very well and reveals two kinetic parameters, the specificity constant and the interfacial quality constant. This approach results in a simple and general model to account for product accumulation in interfacial enzyme kinetics.
Collapse
Affiliation(s)
- Sheereen Majd
- Department of Bioengineering, Pennsylvania State University, University Park, Pennsylvania, USA.
| | | | | | | | | |
Collapse
|
23
|
DeYonker NJ, Webster CE. Phosphoryl transfers of the phospholipase D superfamily: a quantum mechanical theoretical study. J Am Chem Soc 2013; 135:13764-74. [PMID: 24007383 DOI: 10.1021/ja4042753] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The HKD-containing Phospholipase D superfamily catalyzes the cleavage of the headgroup of phosphatidylcholine to produce phosphatidic acid and choline. The mechanism of this cleavage process is studied theoretically. The geometric basis of our models is the X-ray crystal structure of the five-coordinate phosphohistidine intermediate from Streptomyces sp . Strain PMF (PDB Code = 1V0Y ). Hybrid ONIOM QM:QM methodology with Density Functional Theory (DFT) and semiempirical PM6 (DFT:PM6) is used to acquire thermodynamic and kinetic data for the initial phosphoryl transfer, subsequent hydrolysis, and finally, the formation of the experimentally observed ″dead-end″ phosphohistidine product (PDB Code = 1V0W ). The model contains nineteen amino acid residues (including the two highly conserved HKD-motifs), four explicit water molecules, and the substrate. Via computations, the persistence of the short-lived five-coordinate phosphorane intermediate on the minutes times scale is rationalized. This five-coordinate phosphohistidine intermediate energetically exists between the hydrolysis event and ″substrate reorganization″ (the reorganization of the in vitro model substrate within the active site). Computations directly support the thermodynamic favorability of the in vitro four-coordinate phosphohistidine product. In vivo, the activation energy of substrate reorganization is too high, perhaps due to a combination of substrate immobility when embedded in the lipid bilayer, as well as its larger steric bulk compared to the compound used in the in vitro substrate soaks. On this longer time scale, the enzyme will migrate along the lipid membrane toward its next substrate target, rather than promote the formation of the dead-end product.
Collapse
Affiliation(s)
- Nathan J DeYonker
- The Department of Chemistry, The University of Memphis , 213 Smith Chemistry Building, Memphis, Tennessee 38152-3550, United States
| | | |
Collapse
|
24
|
Barig S, Schiemann M, Mirsky VM, Stahmann KP. Quantitative turbidity assay for lipolytic enzymes in microtiter plates. Anal Bioanal Chem 2013; 405:8539-47. [DOI: 10.1007/s00216-013-7283-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Revised: 07/25/2013] [Accepted: 07/29/2013] [Indexed: 01/14/2023]
|
25
|
Assay of phospholipases A(2) and their inhibitors by kinetic analysis in the scooting mode. Mediators Inflamm 2012; 1:85-100. [PMID: 18475447 PMCID: PMC2365326 DOI: 10.1155/s0962935192000164] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Several cellular processes are regulated by interfacial catalysis on biomembrane surfaces. Phospholipases A2 (PLA2) are interesting not only as prototypes for interfacial catalysis, but also because they mobilize precursors for the biosynthesis of eicosanoids and platelet activating factor, and these agents ultimately control a wide range of secretory and inflammatory processes. Since PLA2 carry out their catalytic function at membrane surfaces, the kinetics of these enzymes depends on what the enzyme ‘sees’ at the interface, and thus the observed rate is profoundly influenced by the organization and dynamics of the lipidwater interface (‘quality of the interface’). In this review we elaborate the advantages of monitoring interfacial catalysis in the scooting mode, that is, under the conditions where the enzyme remains bound to vesicles for several thousand catalytic turnover cycles. Such a highly processive catalytic turnover in the scooting mode is useful for a rigorous and quantitative characterization of the kinetics of interfacial catalysis. This analysis is now extended to provide insights into designing strategy for PLA2 assays and screens for their inhibitors.
Collapse
|
26
|
Zhdanov VP, Höök F. Kinetics of the enzyme–vesicle interaction including the formation of rafts and membrane strain. Biophys Chem 2012; 170:17-24. [DOI: 10.1016/j.bpc.2012.06.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Revised: 06/19/2012] [Accepted: 06/28/2012] [Indexed: 11/29/2022]
|
27
|
Noble GT, Craven FL, Voglmeir J, Šardzík R, Flitsch SL, Webb SJ. Accelerated Enzymatic Galactosylation of N-Acetylglucosaminolipids in Lipid Microdomains. J Am Chem Soc 2012; 134:13010-7. [DOI: 10.1021/ja302506t] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Gavin T. Noble
- Manchester Interdisciplinary Biocentre and the School
of Chemistry, University of Manchester,
131 Princess Street, Manchester, M1 7DN, United Kingdom
| | - Faye L. Craven
- Manchester Interdisciplinary Biocentre and the School
of Chemistry, University of Manchester,
131 Princess Street, Manchester, M1 7DN, United Kingdom
| | - Josef Voglmeir
- Manchester Interdisciplinary Biocentre and the School
of Chemistry, University of Manchester,
131 Princess Street, Manchester, M1 7DN, United Kingdom
| | - Robert Šardzík
- Manchester Interdisciplinary Biocentre and the School
of Chemistry, University of Manchester,
131 Princess Street, Manchester, M1 7DN, United Kingdom
| | - Sabine L. Flitsch
- Manchester Interdisciplinary Biocentre and the School
of Chemistry, University of Manchester,
131 Princess Street, Manchester, M1 7DN, United Kingdom
| | - Simon J. Webb
- Manchester Interdisciplinary Biocentre and the School
of Chemistry, University of Manchester,
131 Princess Street, Manchester, M1 7DN, United Kingdom
| |
Collapse
|
28
|
Stock RP, Brewer J, Wagner K, Ramos-Cerrillo B, Duelund L, Jernshøj KD, Olsen LF, Bagatolli LA. Sphingomyelinase D activity in model membranes: structural effects of in situ generation of ceramide-1-phosphate. PLoS One 2012; 7:e36003. [PMID: 22558302 PMCID: PMC3338491 DOI: 10.1371/journal.pone.0036003] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2012] [Accepted: 03/29/2012] [Indexed: 12/11/2022] Open
Abstract
The toxicity of Loxosceles spider venom has been attributed to a rare enzyme, sphingomyelinase D, which transforms sphingomyelin to ceramide-1-phosphate. The bases of its inflammatory and dermonecrotic activity, however, remain unclear. In this work the effects of ceramide-1-phosphate on model membranes were studied both by in situ generation of this lipid using a recombinant sphingomyelinase D from the spider Loxosceles laeta and by pre-mixing it with sphingomyelin and cholesterol. The systems of choice were large unilamellar vesicles for bulk studies (enzyme kinetics, fluorescence spectroscopy and dynamic light scattering) and giant unilamellar vesicles for fluorescence microscopy examination using a variety of fluorescent probes. The influence of membrane lateral structure on the kinetics of enzyme activity and the consequences of enzyme activity on the structure of target membranes containing sphingomyelin were examined. The findings indicate that: 1) ceramide-1-phosphate (particularly lauroyl ceramide-1-phosphate) can be incorporated into sphingomyelin bilayers in a concentration-dependent manner and generates coexistence of liquid disordered/solid ordered domains, 2) the activity of sphingomyelinase D is clearly influenced by the supramolecular organization of its substrate in membranes and, 3) in situ ceramide-1-phosphate generation by enzymatic activity profoundly alters the lateral structure and morphology of the target membranes.
Collapse
Affiliation(s)
- Roberto P. Stock
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, Mexico
- Membrane Biophysics and Biophotonics Group/MEMPHYS, Department of Biochemistry and Molecular Biology, Center for Biomembrane Physics, University of Southern Denmark, Odense, Denmark
| | - Jonathan Brewer
- Membrane Biophysics and Biophotonics Group/MEMPHYS, Department of Biochemistry and Molecular Biology, Center for Biomembrane Physics, University of Southern Denmark, Odense, Denmark
| | - Kerstin Wagner
- Membrane Biophysics and Biophotonics Group/MEMPHYS, Department of Biochemistry and Molecular Biology, Center for Biomembrane Physics, University of Southern Denmark, Odense, Denmark
| | - Blanca Ramos-Cerrillo
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, Mexico
| | - Lars Duelund
- MEMPHYS, Department of Physics, Chemistry and Pharmacy, Center for Biomembrane Physics, University of Southern Denmark, Odense, Denmark
| | - Kit Drescher Jernshøj
- Cellular Complexity Group (CelCom), Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Lars Folke Olsen
- Cellular Complexity Group (CelCom), Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Luis A. Bagatolli
- Membrane Biophysics and Biophotonics Group/MEMPHYS, Department of Biochemistry and Molecular Biology, Center for Biomembrane Physics, University of Southern Denmark, Odense, Denmark
- * E-mail:
| |
Collapse
|
29
|
Petrova S, Atanasov V, Balashev K. Vipoxin and Its Components. STRUCTURAL AND MECHANISTIC ENZYMOLOGY - BRINGING TOGETHER EXPERIMENTS AND COMPUTING 2012; 87:117-53. [DOI: 10.1016/b978-0-12-398312-1.00005-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
|
30
|
Mawn TM, Popov AV, Delikatny EJ. A quantitative continuous enzyme assay of intramolecularly quenched fluorogenic phospholipase substrates for molecular imaging. Anal Biochem 2011; 422:96-102. [PMID: 22230285 DOI: 10.1016/j.ab.2011.12.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2011] [Revised: 12/01/2011] [Accepted: 12/03/2011] [Indexed: 11/29/2022]
Abstract
There has been recent growth in the development of activatable near-infrared (NIR) fluorescent probes for molecular imaging, generally designed by placing fluorochromes on a cleavable substrate in close proximity to one another, such that they self-quench, but fluoresce on separation via enzymatic cleavage of the substrate. Although these probes offer excellent contrast, the detection of enzyme activity has largely only been described qualitatively. In order to assess the effectiveness of a probe, it is useful to have a quantitative measure, such as the enzyme-substrate kinetic parameters. We have developed an assay to determine kinetic parameters and applied it to an intramolecularly quenched molecule, Pyro-PtdEtn-BHQ, a NIR fluorescent probe specific to phosphatidylcholine-specific phospholipase C. The development of this assay includes corrections for intermolecular quenching, calibration, optimization of reaction mixtures, and determination of kinetic and inhibition parameters. This assay can easily be extended to analyze and compare the efficiency of other fluorescent activatable phospholipase probes as suitable molecular imaging agents.
Collapse
Affiliation(s)
- Theresa M Mawn
- Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | | | | |
Collapse
|
31
|
Selvy PE, Lavieri RR, Lindsley CW, Brown HA. Phospholipase D: enzymology, functionality, and chemical modulation. Chem Rev 2011; 111:6064-119. [PMID: 21936578 PMCID: PMC3233269 DOI: 10.1021/cr200296t] [Citation(s) in RCA: 251] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Paige E Selvy
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee 37064, USA
| | | | | | | |
Collapse
|
32
|
Chatterjee C, Sparks DL. Hepatic lipase, high density lipoproteins, and hypertriglyceridemia. THE AMERICAN JOURNAL OF PATHOLOGY 2011; 178:1429-33. [PMID: 21406176 DOI: 10.1016/j.ajpath.2010.12.050] [Citation(s) in RCA: 120] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2010] [Revised: 11/24/2010] [Accepted: 12/03/2010] [Indexed: 11/17/2022]
Abstract
Hepatic lipase (HL) is a lipolytic enzyme that contributes to the regulation of plasma triglyceride (TG) levels. Elevated TG levels may increase the risk of developing coronary heart disease, and studies suggest that mutations in the HL gene may be associated with elevated TG levels and increased risk of coronary heart disease. Hepatic lipase facilitates the clearance of TG from the very low density lipoprotein (VLDL) pool, and this function is governed by the composition and quality of high density lipoprotein (HDL) particles. In humans, HL is a liver resident enzyme regulated by factors that release it from the liver and activate it in the bloodstream. HDL regulates the release of HL from the liver and HDL structure controls HL transport and activation in the circulation. Alterations in HDL-apolipoprotein composition can perturb HL function by inhibiting the release and activation of the enzyme. HDL structure may therefore affect plasma TG levels and coronary heart disease risk.
Collapse
Affiliation(s)
- Cynthia Chatterjee
- Atherosclerosis, Genetics and Cell Biology Group, University of Ottawa Heart Institute, Ottawa, Ontario, Canada
| | | |
Collapse
|
33
|
Balashev K, Atanasov V, Mitewa M, Petrova S, Bjørnholm T. Kinetics of degradation of dipalmitoylphosphatidylcholine (DPPC) bilayers as a result of vipoxin phospholipase A2 activity: An atomic force microscopy (AFM) approach. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1808:191-8. [DOI: 10.1016/j.bbamem.2010.10.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2010] [Revised: 10/04/2010] [Accepted: 10/13/2010] [Indexed: 11/29/2022]
|
34
|
|
35
|
Singh J, Ranganathan R, Hajdu J. Surface dilution kinetics using substrate analog enantiomers as diluents: enzymatic lipolysis by bee venom phospholipase A2. Anal Biochem 2010; 407:253-60. [PMID: 20727845 DOI: 10.1016/j.ab.2010.08.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2010] [Revised: 08/09/2010] [Accepted: 08/10/2010] [Indexed: 01/08/2023]
Abstract
A novel assay employing D-enantiomers of phospholipids as diluents for characterizing surface kinetics of lipid hydrolysis by phospholipases is introduced. The rationales of the method are (i) D-enantiomers resist hydrolysis because of the stereoselectivity of the enzymes toward L-enantiomers and (ii) mixtures of L+D-lipids at various L/D ratios but constant L+D-lipid concentrations yield a surface dilution series of variable L-lipid concentration with constant medium properties. Kinetic characterization of bee venom phospholipase A(2) activity at bile salt+phospholipid aggregate-water interfaces was performed using the mixed L+D-lipid surface dilution assay, and interface kinetic parameters were obtained. The assay applies to biomembrane models as well. Activity was measured by pH-stat methods. Aggregation numbers and interface hydration/microviscosity measured by time-resolved fluorescence quenching and electron spin resonance, respectively, confirmed that interface properties were indeed invariant in a surface dilution series, supporting rationale (ii), and were used to calculate substrate concentrations. Activity data show excellent agreement with a kinetic model derived with D-enantiomers as diluents and also that D-phospholipids bind to the enzyme but resist hydrolysis; underscoring rationale (i). The assay is significant for enabling determination of interface-specific kinetic parameters for the first time and thereby characterization of interface specificity of lipolytic enzymes.
Collapse
Affiliation(s)
- Jasmeet Singh
- Department of Physics and Center for Supramolecular Studies, California State University, Northridge, CA 91330, USA
| | | | | |
Collapse
|
36
|
Leopoldini M, Russo N, Toscano M. Favored Reaction Mechanism of Calcium-Dependent Phospholipase A2. Insights from Density Functional Exploration. J Phys Chem B 2010; 114:11584-93. [DOI: 10.1021/jp1003819] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Monica Leopoldini
- Dipartimento di Chimica and Centro di Calcolo ad Alte Prestazioni per Elaborazioni Parallele e Distribuite-Centro d’Eccellenza MIUR, Università della Calabria, I-87030 Arcavacata di Rende (CS), Italy
| | - Nino Russo
- Dipartimento di Chimica and Centro di Calcolo ad Alte Prestazioni per Elaborazioni Parallele e Distribuite-Centro d’Eccellenza MIUR, Università della Calabria, I-87030 Arcavacata di Rende (CS), Italy
| | - Marirosa Toscano
- Dipartimento di Chimica and Centro di Calcolo ad Alte Prestazioni per Elaborazioni Parallele e Distribuite-Centro d’Eccellenza MIUR, Università della Calabria, I-87030 Arcavacata di Rende (CS), Italy
| |
Collapse
|
37
|
Horchani H, Ben Salem N, Chaari A, Sayari A, Gargouri Y, Verger R. Staphylococcal lipases stereoselectively hydrolyse the sn-2 position of monomolecular films of diglyceride analogs. Application to sn-2 hydrolysis of triolein. J Colloid Interface Sci 2010; 347:301-8. [PMID: 20403605 DOI: 10.1016/j.jcis.2010.03.058] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2010] [Revised: 03/25/2010] [Accepted: 03/26/2010] [Indexed: 11/17/2022]
Abstract
Using the monomolecular film technique, a kinetic study on the stereoselectivity of nine staphylococcal lipase forms was carried out with three pairs of enantiomers from diglyceride analogs (didecanoyl-deoxyamino-O-methyl glycerol, DDG) containing a single hydrolysable decanoyl ester group and two lipase-resistant groups. Our results show that the kinetic profiles of the wild type, the recombinant untagged and the recombinant tagged forms of staphylococcal lipases are significantly different. As with most of the lipases investigated so far, these staphylococcal lipases showed higher catalytic rates with primary esters than with secondary esters. However, it is noteworthy that all these staphylococcal lipases were found to significantly hydrolyse the secondary ester group of diglyceride analogs, with a strong preference for the R configuration. This stereopreference, which was predicted on the basis of Kazlauskas' rule, was comparable to that of Candida rugosa and Pseudomonas glumae lipases. As was to be expected, all the staphylococcal lipases tested efficiently hydrolysed triolein at the sn-2 position. This hydrolytic activity was quantified by performing thin-layer chromatography to analyse the hydrolytic products of triolein. From the qualitative point of view, the sn-2 preferences observed with triolein and diglyceride analogs bearing a secondary ester function were in good agreement. Diglyceride analogs might therefore provide useful initial screening tools for use in future searches for strictly sn-2 specific lipases.
Collapse
Affiliation(s)
- Habib Horchani
- Laboratoire de Biochimie et de Génie Enzymatique des Lipases, ENIS, BPW 3038/1173 Sfax, Tunisia.
| | | | | | | | | | | |
Collapse
|
38
|
Majd S, Yusko EC, MacBriar AD, Yang J, Mayer M. Gramicidin pores report the activity of membrane-active enzymes. J Am Chem Soc 2010; 131:16119-26. [PMID: 19886696 DOI: 10.1021/ja904072s] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Phospholipases constitute a ubiquitous class of membrane-active enzymes that play a key role in cellular signaling, proliferation, and membrane trafficking. Aberrant phospholipase activity is implicated in a range of diseases including cancer, inflammation, and myocardial disease. Characterization of these enzymes is therefore important, both for improving the understanding of phospholipase catalysis and for accelerating pharmaceutical and biotechnological applications. This paper describes a novel approach to monitor, in situ and in real-time, the activity of phospholipase D (PLD) and phospholipase C (PLC) on planar lipid bilayers. This method is based on lipase-induced changes in the electrical charge of lipid bilayers and on the concomitant change in ion concentration near lipid membranes. The approach reports these changes in local ion concentration by a measurable change in the single channel ion conductance through pores of the ion channel-forming peptide gramicidin A. This enzyme assay takes advantage of the amplification characteristics of gramicidin pores to sense the activity of picomolar to nanomolar concentrations of membrane-active enzymes without requiring labeled substrates or products. The resulting method proceeds on lipid bilayers without the need for detergents, quantifies enzyme activity on native lipid substrates within minutes, and provides unique access to both leaflets of well-defined lipid bilayers; this method also makes it possible to generate planar lipid bilayers with transverse lipid asymmetry.
Collapse
Affiliation(s)
- Sheereen Majd
- Department of Chemical Engineering, University of Michigan, 1101 Beal Avenue, Ann Arbor, Michigan 48109-2110, USA
| | | | | | | | | |
Collapse
|
39
|
Kovacic L, Novinec M, Petan T, Baici A, Krizaj I. Calmodulin is a nonessential activator of secretory phospholipase A(2). Biochemistry 2009; 48:11319-28. [PMID: 19839601 DOI: 10.1021/bi901244f] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Ammodytoxins are presynaptically neurotoxic snake venom group IIA secreted phospholipase A(2) enzymes that interact specifically with calmodulin in the cytosol of nerve cells. We show that calmodulin behaves as an activator of ammodytoxin under both nonreducing and reducing (cytosol-like) conditions by stimulating its enzymatic activity up to 21-fold. Kinetic analysis, using a general modifier mechanism, and surface plasmon resonance measurements reveal that calmodulin influences both the catalytic and the vesicle binding properties of the enzyme without affecting its calcium binding properties. The equilibrium dissociation constant of the ammodytoxin-calmodulin complex under cytosol-like conditions is in the low nanomolar range (3 nM), while under nonreducing conditions, the binding affinity is in the subnanomolar range (0.07-0.18 nM). Upon exposure to cytosol-like conditions, ammodytoxin undergoes a slow hysteretic transition to a less active state. Calmodulin stabilizes the conformation of ammodytoxin and thereby restores its activity. These results provide insights into the neurotoxic action of ammodytoxins and the mechanisms involved in the regulation of secreted phospholipase A(2) activity within the cytosol.
Collapse
Affiliation(s)
- Lidija Kovacic
- Department of Molecular and Biomedical Sciences, Jozef Stefan Institute, Ljubljana, Slovenia
| | | | | | | | | |
Collapse
|
40
|
Wacklin HP. Interfacial Mechanism of Phospholipase A2: pH-Dependent Inhibition and Me-β-cyclodextrin Activation. Biochemistry 2009; 48:5874-81. [DOI: 10.1021/bi802280b] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Hanna P. Wacklin
- Australian Nuclear Science and Technology Organisation, PMB1, Menai, NSW 2234, Australia and Institut Laue Langevin, BP 156, 38042 Grenoble Cedex 9, France
| |
Collapse
|
41
|
Shi X, Shao C, Zhang X, Zambonelli C, Redfield AG, Head JF, Seaton BA, Roberts MF. Modulation of Bacillus thuringiensis phosphatidylinositol-specific phospholipase C activity by mutations in the putative dimerization interface. J Biol Chem 2009; 284:15607-18. [PMID: 19369255 DOI: 10.1074/jbc.m901601200] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cleavage of phosphatidylinositol (PI) to inositol 1,2-(cyclic)-phosphate (cIP) and cIP hydrolysis to inositol 1-phosphate by Bacillus thuringiensis phosphatidylinositol-specific phospholipase C are activated by the enzyme binding to phosphatidylcholine (PC) surfaces. Part of this reflects improved binding of the protein to interfaces. However, crystallographic analysis of an interfacially impaired phosphatidylinositol-specific phospholipase (W47A/W242A) suggested protein dimerization might occur on the membrane. In the W47A/W242A dimer, four tyrosine residues from one monomer interact with the same tyrosine cluster of the other, forming a tight dimer interface close to the membrane binding regions. We have constructed mutant proteins in which two or more of these tyrosine residues have been replaced with serine. Phospholipid binding and enzymatic activity of these mutants have been examined to assess the importance of these residues to enzyme function. Replacing two tyrosines had small effects on enzyme activity. However, removal of three or four tyrosine residues weakened PC binding and reduced PI cleavage by the enzyme as well as PC activation of cIP hydrolysis. Crystal structures of Y247S/Y251S in the absence and presence of myo-inositol as well as Y246S/Y247S/Y248S/Y251S indicate that both mutant proteins crystallized as monomers, were very similar to one another, and had no change in the active site region. Kinetic assays, lipid binding, and structural results indicate that either (i) a specific PC binding site, critical for vesicle activities and cIP activation, has been impaired, or (ii) the reduced dimerization potential for Y246S/Y247S/Y248S and Y246S/Y247S/Y248S/Y251S is responsible for their reduced catalytic activity in all assay systems.
Collapse
Affiliation(s)
- Xiaomeng Shi
- Department of Chemistry, Boston College, Chestnut Hill, Massachusetts 02467, USA
| | | | | | | | | | | | | | | |
Collapse
|
42
|
Chiu CR, Huang WN, Wu WG, Yang TS. Fluorescence Single-Molecule Study of Cobra Phospholipase A2Action on a Supported Gel-Phase Lipid Bilayer. Chemphyschem 2009; 10:549-58. [DOI: 10.1002/cphc.200800403] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
43
|
Singh J, Ranganathan R, Hajdu J. Kinetics of Bacterial Phospholipase C Activity at Micellar Interfaces: Effect of Substrate Aggregate Microstructure and a Model for the Kinetic Parameters. J Phys Chem B 2008; 112:16741-51. [DOI: 10.1021/jp807067g] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Jasmeet Singh
- Department of Physics, Department of Chemistry and Biochemistry, and Center for Supramolecular Studies, California State University, Northridge, California 91330-8268
| | - Radha Ranganathan
- Department of Physics, Department of Chemistry and Biochemistry, and Center for Supramolecular Studies, California State University, Northridge, California 91330-8268
| | - Joseph Hajdu
- Department of Physics, Department of Chemistry and Biochemistry, and Center for Supramolecular Studies, California State University, Northridge, California 91330-8268
| |
Collapse
|
44
|
Vallejo AA, Fernández MS. FRET between non-substrate probes detects lateral lipid domain formation during phospholipase A2 interfacial catalysis. Arch Biochem Biophys 2008; 480:1-10. [DOI: 10.1016/j.abb.2008.09.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2008] [Revised: 09/19/2008] [Accepted: 09/25/2008] [Indexed: 10/21/2022]
|
45
|
Comparative study of lipolysis by PLA2 of DOPC substrates organized as monolayers, bilayer vesicles and nanocapsules. Colloids Surf B Biointerfaces 2008; 67:107-14. [DOI: 10.1016/j.colsurfb.2008.08.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2008] [Revised: 07/25/2008] [Accepted: 08/11/2008] [Indexed: 11/22/2022]
|
46
|
Minchiotti M, Scalambro M, Vargas L, Coronel C, Madoery R. Isolation of phospholipase A2 from soybean (Glycine max) seeds. Enzyme Microb Technol 2008. [DOI: 10.1016/j.enzmictec.2007.11.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
|
47
|
Singh J, Unlu Z, Ranganathan R, Griffiths P. Aggregate Properties of Sodium Deoxycholate and Dimyristoylphosphatidylcholine Mixed Micelles. J Phys Chem B 2008; 112:3997-4008. [DOI: 10.1021/jp077380w] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Jasmeet Singh
- Department of Physics and Center for Supramolecular Studies, California State University, Northridge, California 91330-8268
| | - Zuleyha Unlu
- Department of Physics and Center for Supramolecular Studies, California State University, Northridge, California 91330-8268
| | - Radha Ranganathan
- Department of Physics and Center for Supramolecular Studies, California State University, Northridge, California 91330-8268
| | - Peter Griffiths
- School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff, CF10 3AT U.K
| |
Collapse
|
48
|
Boucher JG, Nguyen T, Sparks DL. Lipoprotein electrostatic properties regulate hepatic lipase association and activity. Biochem Cell Biol 2008; 85:696-708. [PMID: 18059528 DOI: 10.1139/o07-137] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The effect of lipoprotein electrostatic properties on the catalytic regulation of hepatic lipase (HL) was investigated. Enrichment of serum or very low density lipoprotein (VLDL) with oleic acid increased lipoprotein negative charge and stimulated lipid hydrolysis by HL. Similarly, enrichment of serum or isolated lipoproteins with the anionic phospholipids phosphatidylinositol (PI), phosphatidic acid, or phosphatidylserine also increased lipoprotein negative charge and stimulated hydrolysis by HL. Anionic lipids had a small effect on phospholipid hydrolysis, but significantly stimulated triacylglyceride (TG) hydrolysis. High density lipoprotein (HDL) charge appears to have a specific effect on lipolysis. Enrichment of HDL with PI significantly stimulated VLDL-TG hydrolysis by HL. To determine whether HDL charge affects the association of HL with HDL and VLDL, HL-lipoprotein interactions were probed immunochemically. Under normal circumstances, HL associates with HDL particles, and only small amounts bind to VLDL. PI enrichment of HDL blocked the binding of HL with HDL. These data indicate that increasing the negative charge of HDL stimulates VLDL-TG hydrolysis by reducing the association of HL with HDL. Therefore, HDL controls the hydrolysis of VLDL by affecting the interlipoprotein association of HL. Lipoprotein electrostatic properties regulate lipase association and are an important regulator of the binding and activity of lipolytic enzymes.
Collapse
Affiliation(s)
- Jonathan G Boucher
- Lipoprotein and Atherosclerosis Research Group, University of Ottawa Heart Institute, 40 Ruskin Street H452, Ottawa, Ontario, Canada
| | | | | |
Collapse
|
49
|
Maggio B, Borioli GA, Del Boca M, De Tullio L, Fanani ML, Oliveira RG, Rosetti CM, Wilke N. Composition-driven surface domain structuring mediated by sphingolipids and membrane-active proteins. Above the nano- but under the micro-scale: mesoscopic biochemical/structural cross-talk in biomembranes. Cell Biochem Biophys 2007; 50:79-109. [PMID: 17968678 DOI: 10.1007/s12013-007-9004-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/28/2007] [Indexed: 10/22/2022]
Abstract
Biomembranes contain a wide variety of lipids and proteins within an essentially two-dimensional structure. The coexistence of such a large number of molecular species causes local tensions that frequently relax into a phase or compositional immiscibility along the lateral and transverse planes of the interface. As a consequence, a substantial microheterogeneity of the surface topography develops and that depends not only on the lipid-protein composition, but also on the lateral and transverse tensions generated as a consequence of molecular interactions. The presence of proteins, and immiscibility among lipids, constitute major perturbing factors for the membrane sculpturing both in terms of its surface topography and dynamics. In this work, we will summarize some recent evidences for the involvement of membrane-associated, both extrinsic and amphitropic, proteins as well as membrane-active phosphohydrolytic enzymes and sphingolipids in driving lateral segregation of phase domains thus determining long-range surface topography.
Collapse
Affiliation(s)
- Bruno Maggio
- Departamento de Química Biológica, Facultad de Ciencias Químicas, Centro de Investigaciones en Química Biológica de Córdoba, Universidad Nacional de Córdoba - CONICET, Argentina.
| | | | | | | | | | | | | | | |
Collapse
|
50
|
Yu BZ, Apitz-Castro RJ, Jain MK, Berg OG. Role of 57-72 loop in the allosteric action of bile salts on pancreatic IB phospholipase A(2): regulation of fat and cholesterol homeostasis. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2007; 1768:2478-90. [PMID: 17603006 DOI: 10.1016/j.bbamem.2007.05.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2007] [Revised: 05/08/2007] [Accepted: 05/22/2007] [Indexed: 11/22/2022]
Abstract
Mono- and biphasic kinetic effects of bile salts on the pancreatic IB phospholipase A2 (PLA2) catalyzed interfacial hydrolysis are characterized. This novel phenomenon is modeled as allosteric action of bile salts with PLA2 at the interface. The results and controls also show that these kinetic effects are not due to surface dilution or solubilization or disruption of the bilayer interface where in the mixed-micelles substrate replenishment becomes the rate-limiting step. The PLA2-catalyzed rate of hydrolysis of zwitterionic dimyristoylphosphatidylcholine (DMPC) vesicles depends on the concentration and structure of the bile salt. The sigmoidal rate increase with cholate saturates at 0.06 mole fraction and changes little at the higher mole fractions. Also, with the rate-lowering bile salts (B), such as taurochenodeoxycholate (TCDOC), the initial sigmoidal rate increase at lower mole fraction is followed by nearly complete reversal to the rate at the pre-activation level at higher mole fractions. The rate-lowering effect of TCDOC is not observed with the (62-66)-loop deleted DeltaPLA2, or with the Naja venom PLA2 that is evolutionarily devoid of the loop. The rate increase is modeled with the assumption that the binding of PLA2 to DMPC interface is cooperatively promoted by bile salt followed by allosteric k(cat)(*)-activation of the bound enzyme by the anionic interface. The rate-lowering effect of bile salts is attributed to the formation of a specific catalytically inert E(*)B complex in the interface, which is noticeably different than the 1:1 EB complex in the aqueous phase. The cholate-activated rate of hydrolysis is lowered by hypolidemic ezetimibe and guggul extract which are not interfacial competitive inhibitors of PLA2. We propose that the biphasic modulation of the pancreatic PLA2 activity by bile salts regulates gastrointestinal fat metabolism and cholesterol homeostasis.
Collapse
Affiliation(s)
- Bao-Zhu Yu
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, USA
| | | | | | | |
Collapse
|