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Aftahy K, Arrasate P, Bashkirov PV, Kuzmin PI, Maurizot V, Huc I, Frolov VA. Molecular Sensing and Manipulation of Protein Oligomerization in Membrane Nanotubes with Bolaamphiphilic Foldamers. J Am Chem Soc 2023; 145:25150-25159. [PMID: 37948300 PMCID: PMC10682987 DOI: 10.1021/jacs.3c05753] [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] [Received: 06/03/2023] [Revised: 10/05/2023] [Accepted: 10/06/2023] [Indexed: 11/12/2023]
Abstract
Adaptive and reversible self-assembly of supramolecular protein structures is a fundamental characteristic of dynamic living matter. However, the quantitative detection and assessment of the emergence of mesoscale protein complexes from small and dynamic oligomeric precursors remains highly challenging. Here, we present a novel approach utilizing a short membrane nanotube (sNT) pulled from a planar membrane reservoir as nanotemplates for molecular reconstruction, manipulation, and sensing of protein oligomerization and self-assembly at the mesoscale. The sNT reports changes in membrane shape and rigidity caused by membrane-bound proteins as variations of the ionic conductivity of the sNT lumen. To confine oligomerization to the sNT, we have designed and synthesized rigid oligoamide foldamer tapes (ROFTs). Charged ROFTs incorporate into the planar and sNT membranes, mediate protein binding to the membranes, and, driven by the luminal electric field, shuttle the bound proteins between the sNT and planar membranes. Using Annexin-V (AnV) as a prototype, we show that the sNT detects AnV oligomers shuttled into the nanotube by ROFTs. Accumulation of AnV on the sNT induces its self-assembly into a curved lattice, restricting the sNT geometry and inhibiting the material uptake from the reservoir during the sNT extension, leading to the sNT fission. By comparing the spontaneous and ROFT-mediated entry of AnV into the sNT, we reveal how intricate membrane curvature sensing by small AnV oligomers controls the lattice self-assembly. These results establish sNT-ROFT as a powerful tool for molecular reconstruction and functional analyses of protein oligomerization and self-assembly, with broad application to various membrane processes.
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Bashkirov PV, Kuzmin PI, Vera Lillo J, Frolov VA. Molecular Shape Solution for Mesoscopic Remodeling of Cellular Membranes. Annu Rev Biophys 2022; 51:473-497. [PMID: 35239417 PMCID: PMC10787580 DOI: 10.1146/annurev-biophys-011422-100054] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Cellular membranes self-assemble from and interact with various molecular species. Each molecule locally shapes the lipid bilayer, the soft elastic core of cellular membranes. The dynamic architecture of intracellular membrane systems is based on elastic transformations and lateral redistribution of these elementary shapes, driven by chemical and curvature stress gradients. The minimization of the total elastic stress by such redistribution composes the most basic, primordial mechanism of membrane curvature-composition coupling (CCC). Although CCC is generally considered in the context of dynamic compositional heterogeneity of cellular membrane systems, in this article we discuss a broader involvement of CCC in controlling membrane deformations. We focus specifically on the mesoscale membrane transformations in open, reservoir-governed systems, such as membrane budding, tubulation, and the emergence of highly curved sites of membrane fusion and fission. We reveal that the reshuffling of molecular shapes constitutes an independent deformation mode with complex rheological properties.This mode controls effective elasticity of local deformations as well as stationary elastic stress, thus emerging as a major regulator of intracellular membrane remodeling.
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Ivchenkov DV, Kuzmin PI, Galimzyanov TR, Shnyrova AV, Bashkirov PV, Frolov VA. Nonlinear material and ionic transport through membrane nanotubes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2021; 1863:183677. [PMID: 34118214 DOI: 10.1016/j.bbamem.2021.183677] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 06/07/2021] [Indexed: 11/29/2022]
Abstract
Membrane nanotubes (NTs) and their networks play an important role in intracellular membrane transport and intercellular communications. The transport characteristics of the NT lumen resemble those of conventional solid-state nanopores. However, unlike the rigid pores, the soft membrane wall of the NT can be deformed by forces driving the transport through the NT lumen. This intrinsic coupling between the NT geometry and transport properties remains poorly explored. Using synchronized fluorescence microscopy and conductance measurements, we revealed that the NT shape was changed by both electric and hydrostatic forces driving the ionic and solute fluxes through the NT lumen. Far from the shape instability, the strength of the force effect is determined by the lateral membrane tension and is scaled with membrane elasticity so that the NT can be operated as a linear elastic sensor. Near shape instabilities, the transport forces triggered large-scale shape transformations, both stochastic and periodic. The periodic oscillations were coupled to a vesicle passage along the NT axis, resembling peristaltic transport. The oscillations were parametrically controlled by the electric field, making NT a highly nonlinear nanofluidic circuitry element with biological and technological implications.
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Bashkirov PV, Kuzmin PI, Chekashkina K, Arrasate P, Vera Lillo J, Shnyrova AV, Frolov VA. Reconstitution and real-time quantification of membrane remodeling by single proteins and protein complexes. Nat Protoc 2020; 15:2443-2469. [PMID: 32591769 PMCID: PMC10839814 DOI: 10.1038/s41596-020-0337-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 04/14/2020] [Indexed: 02/08/2023]
Abstract
Cellular membrane processes, from signal transduction to membrane fusion and fission, depend on acute membrane deformations produced by small and short-lived protein complexes working in conditions far from equilibrium. Real-time monitoring and quantitative assessment of such deformations are challenging; hence, mechanistic analyses of the protein action are commonly based on ensemble averaging, which masks important mechanistic details of the action. In this protocol, we describe how to reconstruct and quantify membrane remodeling by individual proteins and small protein complexes in vitro, using an ultra-short (80- to 400-nm) lipid nanotube (usNT) template. We use the luminal conductance of the usNT as the real-time reporter of the protein interaction(s) with the usNT. We explain how to make and calibrate the usNT template to achieve subnanometer precision in the geometrical assessment of the molecular footprints on the nanotube membrane. We next demonstrate how membrane deformations driven by purified proteins implicated in cellular membrane remodeling can be analyzed at a single-molecule level. The preparation of one usNT takes ~1 h, and the shortest procedure yielding the basic geometrical parameters of a small protein complex takes 10 h.
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Bashkirov PV, Chekashkina KV, Shnyrova AV, Frolov VA. Electrophysiological Methods for Detection of Membrane Leakage and Hemifission by Dynamin 1. Methods Mol Biol 2020; 2159:141-162. [PMID: 32529369 DOI: 10.1007/978-1-0716-0676-6_11] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Membrane fusion and fission are indispensable parts of intracellular membrane recycling and transport. Electrophysiological techniques have been instrumental in discovering and studying fusion and fission pores, the key intermediates shared by both processes. In cells, electrical admittance measurements are used to assess in real time the dynamics of the pore conductance, reflecting the nanoscale transformations of the pore, simultaneously with membrane leakage. Here, we described how this technique is adapted to in vitro mechanistic analyses of membrane fission by dynamin 1 (Dyn1), the protein orchestrating membrane fission in endocytosis. We reconstitute the fission reaction using purified Dyn1 and biomimetic lipid membrane nanotubes of defined geometry. We provide a comprehensive protocol describing simultaneous measurements of the ionic conductance through the nanotube lumen and across the nanotube wall, enabling spatiotemporal correlation between the nanotube constriction by Dyn1, leading to fission and membrane leakage. We present examples of "leaky" and "tight" fission reactions, specify the resolution limits of our method, and discuss how our results support the hemi-fission conjecture.
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Espadas J, Pendin D, Bocanegra R, Escalada A, Misticoni G, Trevisan T, Velasco Del Olmo A, Montagna A, Bova S, Ibarra B, Kuzmin PI, Bashkirov PV, Shnyrova AV, Frolov VA, Daga A. Dynamic constriction and fission of endoplasmic reticulum membranes by reticulon. Nat Commun 2019; 10:5327. [PMID: 31757972 PMCID: PMC6876568 DOI: 10.1038/s41467-019-13327-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Accepted: 10/25/2019] [Indexed: 12/16/2022] Open
Abstract
The endoplasmic reticulum (ER) is a continuous cell-wide membrane network. Network formation has been associated with proteins producing membrane curvature and fusion, such as reticulons and atlastin. Regulated network fragmentation, occurring in different physiological contexts, is less understood. Here we find that the ER has an embedded fragmentation mechanism based upon the ability of reticulon to produce fission of elongating network branches. In Drosophila, Rtnl1-facilitated fission is counterbalanced by atlastin-driven fusion, with the prevalence of Rtnl1 leading to ER fragmentation. Ectopic expression of Drosophila reticulon in COS-7 cells reveals individual fission events in dynamic ER tubules. Consistently, in vitro analyses show that reticulon produces velocity-dependent constriction of lipid nanotubes leading to stochastic fission via a hemifission mechanism. Fission occurs at elongation rates and pulling force ranges intrinsic to the ER, thus suggesting a principle whereby the dynamic balance between fusion and fission controlling organelle morphology depends on membrane motility.
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Bassereau P, Jin R, Baumgart T, Deserno M, Dimova R, Frolov VA, Bashkirov PV, Grubmüller H, Jahn R, Risselada HJ, Johannes L, Kozlov MM, Lipowsky R, Pucadyil TJ, Zeno WF, Stachowiak JC, Stamou D, Breuer A, Lauritsen L, Simon C, Sykes C, Voth GA, Weikl TR. The 2018 biomembrane curvature and remodeling roadmap. JOURNAL OF PHYSICS D: APPLIED PHYSICS 2018; 51:343001. [PMID: 30655651 PMCID: PMC6333427 DOI: 10.1088/1361-6463/aacb98] [Citation(s) in RCA: 161] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
The importance of curvature as a structural feature of biological membranes has been recognized for many years and has fascinated scientists from a wide range of different backgrounds. On the one hand, changes in membrane morphology are involved in a plethora of phenomena involving the plasma membrane of eukaryotic cells, including endo- and exocytosis, phagocytosis and filopodia formation. On the other hand, a multitude of intracellular processes at the level of organelles rely on generation, modulation, and maintenance of membrane curvature to maintain the organelle shape and functionality. The contribution of biophysicists and biologists is essential for shedding light on the mechanistic understanding and quantification of these processes. Given the vast complexity of phenomena and mechanisms involved in the coupling between membrane shape and function, it is not always clear in what direction to advance to eventually arrive at an exhaustive understanding of this important research area. The 2018 Biomembrane Curvature and Remodeling Roadmap of Journal of Physics D: Applied Physics addresses this need for clarity and is intended to provide guidance both for students who have just entered the field as well as established scientists who would like to improve their orientation within this fascinating area.
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Antonny B, Burd C, De Camilli P, Chen E, Daumke O, Faelber K, Ford M, Frolov VA, Frost A, Hinshaw JE, Kirchhausen T, Kozlov MM, Lenz M, Low HH, McMahon H, Merrifield C, Pollard TD, Robinson PJ, Roux A, Schmid S. Membrane fission by dynamin: what we know and what we need to know. EMBO J 2016; 35:2270-2284. [PMID: 27670760 PMCID: PMC5090216 DOI: 10.15252/embj.201694613] [Citation(s) in RCA: 327] [Impact Index Per Article: 40.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 07/25/2016] [Indexed: 12/04/2022] Open
Abstract
The large GTPase dynamin is the first protein shown to catalyze membrane fission. Dynamin and its related proteins are essential to many cell functions, from endocytosis to organelle division and fusion, and it plays a critical role in many physiological functions such as synaptic transmission and muscle contraction. Research of the past three decades has focused on understanding how dynamin works. In this review, we present the basis for an emerging consensus on how dynamin functions. Three properties of dynamin are strongly supported by experimental data: first, dynamin oligomerizes into a helical polymer; second, dynamin oligomer constricts in the presence of GTP; and third, dynamin catalyzes membrane fission upon GTP hydrolysis. We present the two current models for fission, essentially diverging in how GTP energy is spent. We further discuss how future research might solve the remaining open questions presently under discussion.
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Blagonravov ML, Korshunova AY, Azova MM, Bryk AA, Frolov VA. Expression of Bax Protein and Morphological Changes in the Myocardium in Experimental Acute Pressure Overload of the Left Ventricle. Bull Exp Biol Med 2016; 161:312-5. [PMID: 27383165 DOI: 10.1007/s10517-016-3403-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Indexed: 01/11/2023]
Abstract
The expression of Bax protein, marker of intracellular pathway of apoptosis initiation, in viable left ventricular cardiomyocytes and morphological changes in the myocardium in acute pressure overload of the left ventricle were studied in experiment on male rabbits. The content of Bax protein in the cardiomyocyte cytoplasm decreased, this indicating that the mitochondrial pathway was not involved in the realization of the apoptotic program. This decrease was associated with manifest destructive changes in the left ventricular myocardium.
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Mattila JP, Shnyrova AV, Sundborger AC, Hortelano ER, Fuhrmans M, Neumann S, Müller M, Hinshaw JE, Schmid SL, Frolov VA. A hemi-fission intermediate links two mechanistically distinct stages of membrane fission. Nature 2015; 524:109-113. [PMID: 26123023 PMCID: PMC4529379 DOI: 10.1038/nature14509] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2015] [Accepted: 05/05/2015] [Indexed: 12/22/2022]
Abstract
Fusion and fission drive all vesicular transport. Although topologically opposite, these reactions pass through the same hemi-fusion/fission intermediate1,2, characterized by a ‘stalk’ in which only the inner monolayers of the two compartments have merged to form a localized non-bilayer connection1-3. Formation of the hemi-fission intermediate requires energy input from proteins catalyzing membrane remodeling; however the relationship between protein conformational rearrangements and hemi-fusion/fission remains obscure. Here we analyzed how the GTPase cycle of dynamin, the prototypical membrane fission catalyst4-6, is directly coupled to membrane remodeling. We used intra-molecular chemical cross-linking to stabilize dynamin in its GDP•AlF4--bound transition-state. In the absence of GTP this conformer produced stable hemi-fission, but failed to progress to complete fission, even in the presence of GTP. Further analysis revealed that the pleckstrin homology domain (PHD) locked in its membrane-inserted state facilitated hemi-fission. A second mode of dynamin activity, fueled by GTP hydrolysis, couples dynamin disassembly with cooperative diminishing of the PHD wedging, thus destabilizing the hemi-fission intermediate to complete fission. Molecular simulations corroborate the bimodal character of dynamin action and indicate radial and axial forces as dominant, although not independent drivers of hemi-fission and fission transformations, respectively. Mirrored in the fusion reaction7-8, the force bimodality might constitute a general paradigm for leakage-free membrane remodeling.
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Blagonravov ML, Frolov VA, Goryachev VA, Azova MM. Features of the Structure of the Circadian Rhythm of Blood Pressure and Heart Rate under Genetically Determined Hypertension in the Experiment. Bull Exp Biol Med 2015; 158:723-5. [PMID: 25900607 DOI: 10.1007/s10517-015-2846-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Indexed: 11/24/2022]
Abstract
In SHR rats of different ages (22, 26, 30, 34, and 38 weeks), continuous 24-h telemetric monitoring of BP and HR was performed. The amplitude and power of oscillations of diastolic BP significantly decreased at the later stages of arterial hypertension (38 weeks), which was considered as a poor prognostic marker. We also observed a significant decrease in the mean daytime, nighttime, and maximum HR and mesor on weeks 30 and 34, but not on week 38, which can reflect triggering of the adaptive response followed by its exhaustion.
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Azova MM, Blagonravov ML, Frolov VA. Effect of phosphocreatine and ethylmethylhydroxypyridine succinate on the expression of Bax and Bcl-2 proteins in left-ventricular cardiomyocytes of spontaneously hypertensive rats. Bull Exp Biol Med 2015; 158:313-4. [PMID: 25573357 DOI: 10.1007/s10517-015-2749-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2013] [Indexed: 11/29/2022]
Abstract
We studied the effect of phosphocreatine and ethylmethylhydroxypyridine succinate on the expression of Bax and Bcl-2 proteins in left-ventricular cardiomyocytes of spontaneously hypertensive rats (SHR). Both drugs have no effect on the expression of Bcl-2, but significantly reduce the level of Bax protein (phosphocreatine produces more pronounced effect). These data attest to an important role of energy deficit and oxidative stress in the induction of cardiomyocyte apoptosis in genetically determined arterial hypertension.
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Frolov VA, Escalada A, Akimov SA, Shnyrova AV. Geometry of membrane fission. Chem Phys Lipids 2015; 185:129-40. [DOI: 10.1016/j.chemphyslip.2014.07.006] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Revised: 07/16/2014] [Accepted: 07/18/2014] [Indexed: 11/24/2022]
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Geng J, Stannard W, Escalada A, Kim K, Thelen MP, Frolov VA, Noy A. Live Cell Interactions with Biocompatible Ultra-Short Carbon Nanotube Porins. Biophys J 2015. [DOI: 10.1016/j.bpj.2014.11.2664] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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Zotova TI, Frolov VA, Zotov AK, Miandina GI, Komarova AG. [Analysis of the state of coronary arteries in patients with acute coronary syndrome in dependence on the integrin (1-3 gene polymorphism]. KARDIOLOGIYA 2014; 54:10-3. [PMID: 25464604 DOI: 10.18565/cardio.2014.8.10-13] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Aim of this study was to analyze the state of coronary arteries in patients with acute coronary syndrome according to polymorphism of integrin β-3 (ITGB3) gene. All patients were divided into 2 groups: carries and non-carries of PLA2 allele. Carriers of PLA2 allele compared with noncarriers had lesser grades of coronary artery stenoses but greater number of involved arteries. Carriers had more repetitive acute coronary events.
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Shnyrova AV, Bashkirov PV, Akimov SA, Pucadyil TJ, Zimmerberg J, Schmid SL, Frolov VA. Geometric catalysis of membrane fission driven by flexible dynamin rings. Science 2013; 339:1433-6. [PMID: 23520112 PMCID: PMC3980720 DOI: 10.1126/science.1233920] [Citation(s) in RCA: 107] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Biological membrane fission requires protein-driven stress. The guanosine triphosphatase (GTPase) dynamin builds up membrane stress by polymerizing into a helical collar that constricts the neck of budding vesicles. How this curvature stress mediates nonleaky membrane remodeling is actively debated. Using lipid nanotubes as substrates to directly measure geometric intermediates of the fission pathway, we found that GTP hydrolysis limits dynamin polymerization into short, metastable collars that are optimal for fission. Collars as short as two rungs translated radial constriction to reversible hemifission via membrane wedging of the pleckstrin homology domains (PHDs) of dynamin. Modeling revealed that tilting of the PHDs to conform with membrane deformations creates the low-energy pathway for hemifission. This local coordination of dynamin and lipids suggests how membranes can be remodeled in cells.
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Escalada A, Shnyrova AV, Waters H, Zimmerberg J, Frolov VA. Curvature Stimulates Assembly of Gag Shell through Distinct Fluid-Like Intermediate. Biophys J 2013. [DOI: 10.1016/j.bpj.2012.11.2320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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18
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Hortelano ER, Shnyrova AV, Frolov VA. Quantification of Curvature Gradients in Highly Curved Tubular Lipid Bilayers. Biophys J 2013. [DOI: 10.1016/j.bpj.2012.11.1372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Zotova TI, Miandina GI, Frolov VA, Komarova AG, Zotov AK. [The influence of ITGB3 gene polymorphism on the frequency of arterial hypertension in patients with acute coronary syndrome]. KLINICHESKAIA MEDITSINA 2013; 91:22-24. [PMID: 24437179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
PLA polymorphism of platelet integrin receptor, GpIIIa glycoprotein, (PLA polymorphism of the ITGB3 gene) is associated with the risk of myocardial infarction and CHD especially in young subjects. We analyzed ITGB3 gene polymorphism in patients with acute coronary insufficiency. It was shown that increased AP and altered blood lipid spectrum in the acute period of disease in carriers of the PLA allele (PLA1/PLA2 and PLA2/PLA2 genotypes) can be regarded as manifestations of stress reaction. The data obtained indicate that the PLA2 allele is a predictor of complications of acute coronary insufficiency. This observation is of importance for the choice of adequate therapy for the patients with this disorder.
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Blagonravov ML, Azova MM, Onufriev MV, Frolov VA. Activities of some caspase cascade enzymes and myocardial contractility in experimental left ventricular focal ischemia. Bull Exp Biol Med 2012; 150:672-5. [PMID: 22235413 DOI: 10.1007/s10517-011-1219-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Focal left ventricular ischemia was modeled in male Chinchilla rabbits. Activities of caspase-3 and caspase-8 in the left and right ventricular myocardium and myocardial contractility were studied after 1, 3, and 5 days. Caspase-3 activity increased significantly in the left ventricular peri-infarction zone and right ventricular myocardium, while caspase-8 activity did not differ from the control. Left ventricular contractility decreased significantly and the hemodynamic load of the right ventricle sharply increased. These results attest to induction of the internal (mitochondrial) pathway of apoptosis in myocardial cells most likely caused by left ventricular hypoxia and right ventricular overload.
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Frolov VA, Blagonravov ML, Zotov AK, Zotova TJ. Staging of hemodynamic parameters during development of experimental arterial hypertension in rabbits. Bull Exp Biol Med 2012; 151:9-12. [PMID: 22442791 DOI: 10.1007/s10517-011-1247-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The study analyzed changes in parameters of the central and intracardiac hemodynamics during the development of experimental arterial hypertension, which were assessed as the adaptive in nature. The development of hypertension demonstrated staging of the adaptive processes. The development of the adaptive responses was characterized by changes in the magnitude and probabilistic distribution of the hemodynamic parameters.
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Akimov SA, Kuzmin PI, Frolov VA. Coordination of Bending and Wedging in Membrane Fission. Biophys J 2012. [DOI: 10.1016/j.bpj.2011.11.1765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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23
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Azova MM, Blagonravov ML, Frolov VA. [The effect of ETA receptor blockade on cardiomyocyte apoptosis and myocardial hypertrophy development in genetically hypertensive rats]. EKSPERIMENTAL'NAIA I KLINICHESKAIA FARMAKOLOGIIA 2012; 75:22-24. [PMID: 23700663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Cardiomyocyte apoptosis and hypertrophy have been studied in the left and right ventricular myocardium of spontaneously hypertensive rats without treatment and after 10-day administration of the ETA-receptor antagonist BQ-123. It is established that BQ-123 prevents the activation of cardiomyocyte apoptosis and significantly decreases the extent of hypertrophy development in the left ventricular myocardium, but does not influence the same mechanisms in the right ventricular myocardium.
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MESH Headings
- Animals
- Antihypertensive Agents/pharmacology
- Apoptosis/drug effects
- Endothelin A Receptor Antagonists
- Heart Ventricles/drug effects
- Heart Ventricles/metabolism
- Heart Ventricles/physiopathology
- Hypertrophy, Left Ventricular/metabolism
- Hypertrophy, Left Ventricular/physiopathology
- Hypertrophy, Left Ventricular/prevention & control
- Hypertrophy, Right Ventricular/metabolism
- Hypertrophy, Right Ventricular/physiopathology
- Myocytes, Cardiac/drug effects
- Peptides, Cyclic/pharmacology
- Rats
- Rats, Inbred SHR
- Rats, Inbred WKY
- Receptor, Endothelin A/metabolism
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Frolov VA, Shnyrova AV, Zimmerberg J. Lipid polymorphisms and membrane shape. Cold Spring Harb Perspect Biol 2011; 3:a004747. [PMID: 21646378 DOI: 10.1101/cshperspect.a004747] [Citation(s) in RCA: 140] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Morphological plasticity of biological membrane is critical for cellular life, as cells need to quickly rearrange their membranes. Yet, these rearrangements are constrained in two ways. First, membrane transformations may not lead to undesirable mixing of, or leakage from, the participating cellular compartments. Second, membrane systems should be metastable at large length scales, ensuring the correct function of the particular organelle and its turnover during cellular division. Lipids, through their ability to exist with many shapes (polymorphism), provide an adequate construction material for cellular membranes. They can self-assemble into shells that are very flexible, albeit hardly stretchable, which allows for their far-reaching morphological and topological behaviors. In this article, we will discuss the importance of lipid polymorphisms in the shaping of membranes and its role in controlling cellular membrane morphology.
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Abstract
Dynamin, best studied for its role in clathrin-mediated endocytosis, is the prototypical member of a family of multidomain GTPases involved in fission and remodeling of multiple organelles. Recent studies have shown that dynamin alone can catalyze fission of membrane tubules and vesicle formation from planar lipid templates. Thus, dynamin appears to be a self-sufficient fission machine. Here we review the biochemical activities and structural features of dynamin required for fission activity. As all changes in membrane topology require energetically unfavorable rearrangements of the lipid bilayer, we discuss the interplay between dynamin and its lipid substrates that are critical to defining a nonleaky pathway to membrane fission. We propose a two-stage model for dynamin-catalyzed fission. In stage one, dynamin's mechanochemical activities induce localized curvature stress and position its lipid-interacting pleckstrin homology domains to create a catalytic center that, in stage two, guides lipid remodeling through hemifission intermediates to drive membrane fission.
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