1
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Jain S, Boyer D, Pal A, Dagdug L. Fick-Jacobs description and first passage dynamics for diffusion in a channel under stochastic resetting. J Chem Phys 2023; 158:054113. [PMID: 36754825 DOI: 10.1063/5.0135249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023] Open
Abstract
The transport of particles through channels is of paramount importance in physics, chemistry, and surface science due to its broad real world applications. Much insight can be gained by observing the transition paths of a particle through a channel and collecting statistics on the lifetimes in the channel or the escape probabilities from the channel. In this paper, we consider the diffusive transport through a narrow conical channel of a Brownian particle subject to intermittent dynamics, namely, stochastic resetting. As such, resetting brings the particle back to a desired location from where it resumes its diffusive phase. To this end, we extend the Fick-Jacobs theory of channel-facilitated diffusive transport to resetting-induced transport. Exact expressions for the conditional mean first passage times, escape probabilities, and the total average lifetime in the channel are obtained, and their behavior as a function of the resetting rate is highlighted. It is shown that resetting can expedite the transport through the channel-rigorous constraints for such conditions are then illustrated. Furthermore, we observe that a carefully chosen resetting rate can render the average lifetime of the particle inside the channel minimal. Interestingly, the optimal rate undergoes continuous and discontinuous transitions as some relevant system parameters are varied. The validity of our one-dimensional analysis and the corresponding theoretical predictions is supported by three-dimensional Brownian dynamics simulations. We thus believe that resetting can be useful to facilitate particle transport across biological membranes-a phenomenon that can spearhead further theoretical and experimental studies.
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Affiliation(s)
- Siddharth Jain
- Harish-Chandra Research Institute, HBNI, Chhatnag Road, Jhunsi, Allahabad (Prayagraj), UP, 211019, India
| | - Denis Boyer
- Instituto de Física, Universidad Nacional Autónoma de México, Ciudad de México C.P. 04510, Mexico
| | - Arnab Pal
- The Institute of Mathematical Sciences, CIT Campus, Taramani, Chennai 600113, India
| | - Leonardo Dagdug
- Physics Department, Universidad Autónoma Metropolitana-Iztapalapa, San Rafael Atlixco 186, Ciudad de México 09340, Mexico
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2
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The Potential Role of Voltage-Dependent Anion Channel in the Treatment of Parkinson’s Disease. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2022:4665530. [PMID: 36246397 PMCID: PMC9556184 DOI: 10.1155/2022/4665530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 09/11/2022] [Accepted: 09/20/2022] [Indexed: 11/18/2022]
Abstract
Parkinson’s disease (PD) is a neurodegenerative disease second only to Alzheimer’s disease in terms of prevalence. Previous studies have indicated that the occurrence and progression of PD are associated with mitochondrial dysfunction. Mitochondrial dysfunction is one of the most important causes for apoptosis of dopaminergic neurons. Therefore, maintaining the stability of mitochondrial functioning is a potential strategy in the treatment of PD. Voltage-dependent anion channel (VDAC) is the main component in the outer mitochondrial membrane, and it participates in a variety of biological processes. In this review, we focus on the potential roles of VDACs in the treatment of PD. We found that VDACs are involved in PD by regulating apoptosis, autophagy, and ferroptosis. VDAC1 oligomerization, VDACs ubiquitination, regulation of mitochondrial permeability transition pore (mPTP) by VDACs, and interaction between VDACs and α-synuclein (α-syn) are all promising methods for the treatment of PD. We proposed that inhibition of VDAC1 oligomerization and promotion of VDAC1 ubiquitination as an effective approach for the treatment of PD. Previous studies have proven that the expression of VDAC1 has a significant change in PD models. The expression levels of VDAC1 are decreased in the substantia nigra (SN) of patients suffering from PD compared with the control group consisting of normal individuals by using bioinformatics tools. VDAC2 is involved in PD mainly through the regulation of apoptosis. VDAC3 may have a similar function to VDAC1. It can be concluded that the functional roles of VDACs contribute to the therapeutic strategy of PD.
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3
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Rajendran M, Queralt-Martín M, Gurnev PA, Rosencrans WM, Rovini A, Jacobs D, Abrantes K, Hoogerheide DP, Bezrukov SM, Rostovtseva TK. Restricting α-synuclein transport into mitochondria by inhibition of α-synuclein-VDAC complexation as a potential therapeutic target for Parkinson's disease treatment. Cell Mol Life Sci 2022; 79:368. [PMID: 35718804 PMCID: PMC11072225 DOI: 10.1007/s00018-022-04389-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 05/13/2022] [Accepted: 05/20/2022] [Indexed: 11/03/2022]
Abstract
Involvement of alpha-synuclein (αSyn) in Parkinson's disease (PD) is complicated and difficult to trace on cellular and molecular levels. Recently, we established that αSyn can regulate mitochondrial function by voltage-activated complexation with the voltage-dependent anion channel (VDAC) on the mitochondrial outer membrane. When complexed with αSyn, the VDAC pore is partially blocked, reducing the transport of ATP/ADP and other metabolites. Further, αSyn can translocate into the mitochondria through VDAC, where it interferes with mitochondrial respiration. Recruitment of αSyn to the VDAC-containing lipid membrane appears to be a crucial prerequisite for both the blockage and translocation processes. Here we report an inhibitory effect of HK2p, a small membrane-binding peptide from the mitochondria-targeting N-terminus of hexokinase 2, on αSyn membrane binding, and hence on αSyn complex formation with VDAC and translocation through it. In electrophysiology experiments, the addition of HK2p at micromolar concentrations to the same side of the membrane as αSyn results in a dramatic reduction of the frequency of blockage events in a concentration-dependent manner, reporting on complexation inhibition. Using two complementary methods of measuring protein-membrane binding, bilayer overtone analysis and fluorescence correlation spectroscopy, we found that HK2p induces detachment of αSyn from lipid membranes. Experiments with HeLa cells using proximity ligation assay confirmed that HK2p impedes αSyn entry into mitochondria. Our results demonstrate that it is possible to regulate αSyn-VDAC complexation by a rationally designed peptide, thus suggesting new avenues in the search for peptide therapeutics to alleviate αSyn mitochondrial toxicity in PD and other synucleinopathies.
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Affiliation(s)
- Megha Rajendran
- Section On Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 9000 Rockville Pike, Bldg. 29B, Room 1G09, Bethesda, MD, 20892, USA
| | - María Queralt-Martín
- Section On Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 9000 Rockville Pike, Bldg. 29B, Room 1G09, Bethesda, MD, 20892, USA
- Laboratory of Molecular Biophysics, Department of Physics, Universitat Jaume I, Castellón, 12071, Spain
| | - Philip A Gurnev
- Section On Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 9000 Rockville Pike, Bldg. 29B, Room 1G09, Bethesda, MD, 20892, USA
| | - William M Rosencrans
- Section On Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 9000 Rockville Pike, Bldg. 29B, Room 1G09, Bethesda, MD, 20892, USA
| | - Amandine Rovini
- Section On Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 9000 Rockville Pike, Bldg. 29B, Room 1G09, Bethesda, MD, 20892, USA
| | - Daniel Jacobs
- Section On Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 9000 Rockville Pike, Bldg. 29B, Room 1G09, Bethesda, MD, 20892, USA
| | - Kaitlin Abrantes
- Section On Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 9000 Rockville Pike, Bldg. 29B, Room 1G09, Bethesda, MD, 20892, USA
| | - David P Hoogerheide
- Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA
| | - Sergey M Bezrukov
- Section On Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 9000 Rockville Pike, Bldg. 29B, Room 1G09, Bethesda, MD, 20892, USA
| | - Tatiana K Rostovtseva
- Section On Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 9000 Rockville Pike, Bldg. 29B, Room 1G09, Bethesda, MD, 20892, USA.
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4
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Brinkerhoff H, Kang ASW, Liu J, Aksimentiev A, Dekker C. Multiple rereads of single proteins at single-amino acid resolution using nanopores. Science 2021; 374:1509-1513. [PMID: 34735217 DOI: 10.1126/science.abl4381] [Citation(s) in RCA: 181] [Impact Index Per Article: 60.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Henry Brinkerhoff
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, 2629 HZ Delft, Netherlands
| | - Albert S W Kang
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, 2629 HZ Delft, Netherlands
| | - Jingqian Liu
- Center for Biophysics and Quantitative Biology and Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Aleksei Aksimentiev
- Center for Biophysics and Quantitative Biology and Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Cees Dekker
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, 2629 HZ Delft, Netherlands
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5
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Hoogerheide DP, Gurnev PA, Rostovtseva TK, Bezrukov SM. Voltage-activated complexation of α-synuclein with three diverse β-barrel channels: VDAC, MspA, and α-hemolysin. Proteomics 2021; 22:e2100060. [PMID: 34813679 DOI: 10.1002/pmic.202100060] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 11/12/2021] [Accepted: 11/15/2021] [Indexed: 01/07/2023]
Abstract
Voltage-activated complexation is the process by which a transmembrane potential drives complex formation between a membrane-embedded channel and a soluble or membrane-peripheral target protein. Metabolite and calcium flux across the mitochondrial outer membrane was shown to be regulated by voltage-activated complexation of the voltage-dependent anion channel (VDAC) and either dimeric tubulin or α-synuclein (αSyn). However, the roles played by VDAC's characteristic attributes-its anion selectivity and voltage gating behavior-have remained unclear. Here, we compare in vitro measurements of voltage-activated complexation of αSyn with three well-characterized β-barrel channels-VDAC, MspA, and α-hemolysin-that differ widely in their organism of origin, structure, geometry, charge density distribution, and voltage gating behavior. The voltage dependences of the complexation dynamics for the different channels are observed to differ quantitatively but have similar qualitative features. In each case, energy landscape modeling describes the complexation dynamics in a manner consistent with the known properties of the individual channels, while voltage gating does not appear to play a role. The reaction free energy landscapes thus calculated reveal a non-trivial dependence of the αSyn/channel complex stability on the surface density of αSyn.
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Affiliation(s)
- David P Hoogerheide
- Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland, USA
| | - Philip A Gurnev
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Tatiana K Rostovtseva
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, 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, USA
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6
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Hoogerheide DP, Rostovtseva TK, Bezrukov SM. Exploring lipid-dependent conformations of membrane-bound α-synuclein with the VDAC nanopore. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2021; 1863:183643. [PMID: 33971161 PMCID: PMC8255272 DOI: 10.1016/j.bbamem.2021.183643] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 04/21/2021] [Accepted: 04/26/2021] [Indexed: 02/07/2023]
Abstract
Regulation of VDAC by α-synuclein (αSyn) is a rich and instructive example of protein-protein interactions catalyzed by a lipid membrane surface. αSyn, a peripheral membrane protein involved in Parkinson's disease pathology, is known to bind to membranes in a transient manner. αSyn's negatively charged C-terminal domain is then available to be electromechanically trapped by the VDAC β-barrel, a process that is observed in vitro as the reversible reduction of ion flow through a single voltage-biased VDAC nanopore. Binding of αSyn to the lipid bilayer is a prerequisite of the channel-protein interaction; surprisingly, however, we find that the strength of αSyn binding to the membrane does not correlate in any simple way with its efficiency of blocking VDAC, suggesting that the lipid-dependent conformations of the membrane-bound αSyn control the interaction. Quantitative models of the free energy landscape governing the capture and release processes allow us to discriminate between several αSyn (sub-) conformations on the membrane surface. These results, combined with known structural features of αSyn on anionic lipid membranes, point to a model in which the lipid composition determines the fraction of αSyn molecules for which the charged C terminal domain is constrained to be close, but not tightly bound, to the membrane surface and thus readily captured by the VDAC nanopore. We speculate that changes in the mitochondrial membrane lipid composition may be key regulators of the αSyn-VDAC interaction and consequently of VDAC-facilitated transport of ions and metabolites in and out of mitochondria and, i.e. mitochondrial metabolism.
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Affiliation(s)
- David P Hoogerheide
- Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Tatiana K Rostovtseva
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 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, MD 20892, USA
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7
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Robertson JW, Ghimire M, Reiner JE. Nanopore sensing: A physical-chemical approach. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2021; 1863:183644. [PMID: 33989531 PMCID: PMC9793329 DOI: 10.1016/j.bbamem.2021.183644] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 04/22/2021] [Accepted: 04/26/2021] [Indexed: 12/30/2022]
Abstract
Protein nanopores have emerged as an important class of sensors for the understanding of biophysical processes, such as molecular transport across membranes, and for the detection and characterization of biopolymers. Here, we trace the development of these sensors from the Coulter counter and squid axon studies to the modern applications including exquisite detection of small volume changes and molecular reactions at the single molecule (or reactant) scale. This review focuses on the chemistry of biological pores, and how that influences the physical chemistry of molecular detection.
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Affiliation(s)
- Joseph W.F. Robertson
- Biophysical and Biomedical Measurement Group, Microsystems and Nanotechnology Division, Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg MD. 20899, correspondence to:
| | - Madhav Ghimire
- Department of Physics, Virginia Commonwealth University, Richmond, VA
| | - Joseph E. Reiner
- Department of Physics, Virginia Commonwealth University, Richmond, VA
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8
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Rostovtseva TK, Bezrukov SM, Hoogerheide DP. Regulation of Mitochondrial Respiration by VDAC Is Enhanced by Membrane-Bound Inhibitors with Disordered Polyanionic C-Terminal Domains. Int J Mol Sci 2021; 22:ijms22147358. [PMID: 34298976 PMCID: PMC8306229 DOI: 10.3390/ijms22147358] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 06/29/2021] [Accepted: 07/01/2021] [Indexed: 12/18/2022] Open
Abstract
The voltage-dependent anion channel (VDAC) is the primary regulating pathway of water-soluble metabolites and ions across the mitochondrial outer membrane. When reconstituted into lipid membranes, VDAC responds to sufficiently large transmembrane potentials by transitioning to gated states in which ATP/ADP flux is reduced and calcium flux is increased. Two otherwise unrelated cytosolic proteins, tubulin, and α-synuclein (αSyn), dock with VDAC by a novel mechanism in which the transmembrane potential draws their disordered, polyanionic C-terminal domains into and through the VDAC channel, thus physically blocking the pore. For both tubulin and αSyn, the blocked state is observed at much lower transmembrane potentials than VDAC gated states, such that in the presence of these cytosolic docking proteins, VDAC’s sensitivity to transmembrane potential is dramatically increased. Remarkably, the features of the VDAC gated states relevant for bioenergetics—reduced metabolite flux and increased calcium flux—are preserved in the blocked state induced by either docking protein. The ability of tubulin and αSyn to modulate mitochondrial potential and ATP production in vivo is now supported by many studies. The common physical origin of the interactions of both tubulin and αSyn with VDAC leads to a general model of a VDAC inhibitor, facilitates predictions of the effect of post-translational modifications of known inhibitors, and points the way toward the development of novel therapeutics targeting VDAC.
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Affiliation(s)
- Tatiana K. Rostovtseva
- Program in Physical Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA;
- Correspondence:
| | - Sergey M. Bezrukov
- Program in Physical Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA;
| | - David P. Hoogerheide
- Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA;
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9
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Queralt-Martín M, Bergdoll L, Teijido O, Munshi N, Jacobs D, Kuszak AJ, Protchenko O, Reina S, Magrì A, De Pinto V, Bezrukov SM, Abramson J, Rostovtseva TK. A lower affinity to cytosolic proteins reveals VDAC3 isoform-specific role in mitochondrial biology. J Gen Physiol 2021; 152:133600. [PMID: 31935282 PMCID: PMC7062508 DOI: 10.1085/jgp.201912501] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 11/20/2019] [Indexed: 01/30/2023] Open
Abstract
Voltage-dependent anion channel (VDAC) is the major pathway for the transport of ions and metabolites across the mitochondrial outer membrane. Among the three known mammalian VDAC isoforms, VDAC3 is the least characterized, but unique functional roles have been proposed in cellular and animal models. Yet, a high-sequence similarity between VDAC1 and VDAC3 is indicative of a similar pore-forming structure. Here, we conclusively show that VDAC3 forms stable, highly conductive voltage-gated channels that, much like VDAC1, are weakly anion selective and facilitate metabolite exchange, but exhibit unique properties when interacting with the cytosolic proteins α-synuclein and tubulin. These two proteins are known to be potent regulators of VDAC1 and induce similar characteristic blockages (on the millisecond time scale) of VDAC3, but with 10- to 100-fold reduced on-rates and altered α-synuclein blocking times, indicative of an isoform-specific function. Through cysteine scanning mutagenesis, we found that VDAC3's cysteine residues regulate its interaction with α-synuclein, demonstrating VDAC3-unique functional properties and further highlighting a general molecular mechanism for VDAC isoform-specific regulation of mitochondrial bioenergetics.
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Affiliation(s)
- María Queralt-Martín
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD
| | - Lucie Bergdoll
- Department of Physiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA
| | - Oscar Teijido
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD
| | - Nabill Munshi
- Department of Physiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA
| | - Daniel Jacobs
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD
| | - Adam J Kuszak
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD
| | - Olga Protchenko
- Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD
| | - Simona Reina
- Department of Biological, Geological and Environmental Sciences, University of Catania, Catania, Italy
| | - Andrea Magrì
- Department of Biological, Geological and Environmental Sciences, University of Catania, Catania, Italy
| | - Vito De Pinto
- Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Sergey M Bezrukov
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD
| | - Jeff Abramson
- Department of Physiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA
| | - Tatiana K Rostovtseva
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD
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10
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Neurons and Glia Interplay in α-Synucleinopathies. Int J Mol Sci 2021; 22:ijms22094994. [PMID: 34066733 PMCID: PMC8125822 DOI: 10.3390/ijms22094994] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 04/29/2021] [Accepted: 05/04/2021] [Indexed: 11/16/2022] Open
Abstract
Accumulation of the neuronal presynaptic protein alpha-synuclein within proteinaceous inclusions represents the key histophathological hallmark of a spectrum of neurodegenerative disorders, referred to by the umbrella term a-synucleinopathies. Even though alpha-synuclein is expressed predominantly in neurons, pathological aggregates of the protein are also found in the glial cells of the brain. In Parkinson's disease and dementia with Lewy bodies, alpha-synuclein accumulates mainly in neurons forming the Lewy bodies and Lewy neurites, whereas in multiple system atrophy, the protein aggregates mostly in the glial cytoplasmic inclusions within oligodendrocytes. In addition, astrogliosis and microgliosis are found in the synucleinopathy brains, whereas both astrocytes and microglia internalize alpha-synuclein and contribute to the spread of pathology. The mechanisms underlying the pathological accumulation of alpha-synuclein in glial cells that under physiological conditions express low to non-detectable levels of the protein are an area of intense research. Undoubtedly, the presence of aggregated alpha-synuclein can disrupt glial function in general and can contribute to neurodegeneration through numerous pathways. Herein, we summarize the current knowledge on the role of alpha-synuclein in both neurons and glia, highlighting the contribution of the neuron-glia connectome in the disease initiation and progression, which may represent potential therapeutic target for a-synucleinopathies.
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11
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Angevine CE, Robertson JWF, Dass A, Reiner JE. Laser-based temperature control to study the roles of entropy and enthalpy in polymer-nanopore interactions. SCIENCE ADVANCES 2021; 7:7/17/eabf5462. [PMID: 33883140 PMCID: PMC8059931 DOI: 10.1126/sciadv.abf5462] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 03/04/2021] [Indexed: 05/05/2023]
Abstract
Single-molecule approaches for probing the free energy of confinement for polymers in a nanopore environment are critical for the development of nanopore biosensors. We developed a laser-based nanopore heating approach to monitor the free energy profiles of such a single-molecule sensor. Using this approach, we measure the free energy profiles of two distinct polymers, polyethylene glycol and water-soluble peptides, as they interact with the nanopore sensor. Polyethylene glycol demonstrates a retention mechanism dominated by entropy with little sign of interaction with the pore, while peptides show an enthalpic mechanism, which can be attributed to physisorption to the nanopore (e.g., hydrogen bonding). To manipulate the energetics, we introduced thiolate-capped gold clusters [Au25(SG)18] into the pore, which increases the charge and leads to additional electrostatic interactions that help dissect the contribution that enthalpy and entropy make in this modified environment. These observations provide a benchmark for optimization of single-molecule nanopore sensors.
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Affiliation(s)
| | - Joseph W F Robertson
- Biophysics Group, Microsystems and Nanotechnology Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA.
| | - Amala Dass
- Department of Chemistry and Biochemistry, University of Mississippi, University, MS 38677, USA
| | - Joseph E Reiner
- Department of Physics, Virginia Commonwealth University, Richmond, VA 23284, USA.
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12
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Rosencrans WM, Rajendran M, Bezrukov SM, Rostovtseva TK. VDAC regulation of mitochondrial calcium flux: From channel biophysics to disease. Cell Calcium 2021; 94:102356. [PMID: 33529977 PMCID: PMC7914209 DOI: 10.1016/j.ceca.2021.102356] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 01/06/2021] [Accepted: 01/06/2021] [Indexed: 12/14/2022]
Abstract
Voltage-dependent anion channel (VDAC), the most abundant mitochondrial outer membrane protein, is important for a variety of mitochondrial functions including metabolite exchange, calcium transport, and apoptosis. While VDAC's role in shuttling metabolites between the cytosol and mitochondria is well established, there is a growing interest in understanding the mechanisms of its regulation of mitochondrial calcium transport. Here we review the current literature on VDAC's role in calcium signaling, its biophysical properties, physiological function, and pathology focusing on its importance in cardiac diseases. We discuss the specific biophysical properties of the three VDAC isoforms in mammalian cells-VDAC 1, 2, and 3-in relationship to calcium transport and their distinct roles in cell physiology and disease. Highlighting the emerging evidence that cytosolic proteins interact with VDAC and regulate its calcium permeability, we advocate for continued investigation into the VDAC interactome at the contact sites between mitochondria and organelles and its role in mitochondrial calcium transport.
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Affiliation(s)
- William M Rosencrans
- Section on Molecular Transport, Eunice Kennedy Shriver. National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, 20892, United States
| | - Megha Rajendran
- Section on Molecular Transport, Eunice Kennedy Shriver. National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, 20892, United States
| | - Sergey M Bezrukov
- Section on Molecular Transport, Eunice Kennedy Shriver. National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, 20892, United States
| | - Tatiana K Rostovtseva
- Section on Molecular Transport, Eunice Kennedy Shriver. National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, 20892, United States.
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13
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Abstract
The evolution of the eukaryotic cell from the primal endosymbiotic event involved a complex series of adaptations driven primarily by energy optimization. Transfer of genes from endosymbiont to host and concomitant expansion (by infolding) of the endosymbiont's chemiosmotic membrane greatly increased output of adenosine triphosphate (ATP) and placed selective pressure on the membrane at the host-endosymbiont interface to sustain the energy advantage. It is hypothesized that critical functions at this interface (metabolite exchange, polypeptide import, barrier integrity to proteins and DNA) were managed by a precursor β-barrel protein ("pβB") from which the voltage-dependent anion-selective channel (VDAC) descended. VDAC's role as hub for disparate and increasingly complex processes suggests an adaptability that likely springs from a feature inherited from pβB, retained because of important advantages conferred. It is proposed that this property is the remarkable structural flexibility evidenced in VDAC's gating mechanism, a possible origin of which is discussed.
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Affiliation(s)
- Carmen A Mannella
- Department of Physiology, Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 20201, USA
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14
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Rosencrans WM, Aguilella VM, Rostovtseva TK, Bezrukov SM. α-Synuclein emerges as a potent regulator of VDAC-facilitated calcium transport. Cell Calcium 2021; 95:102355. [PMID: 33578201 DOI: 10.1016/j.ceca.2021.102355] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 01/04/2021] [Indexed: 02/06/2023]
Abstract
Voltage-dependent anion channel (VDAC) is the most ubiquitous channel at the mitochondrial outer membrane, and is believed to be the pathway for calcium entering or leaving the mitochondria. Therefore, understanding the molecular mechanisms of how VDAC regulates calcium influx and efflux from the mitochondria is of particular interest for mitochondrial physiology. When the Parkinson's disease (PD) related neuronal protein, alpha-synuclein (αSyn), is added to the reconstituted VDAC, it reversibly and partially blocks VDAC conductance by its acidic C-terminal tail. Using single-molecule VDAC electrophysiology of reconstituted VDAC we now demonstrate that, at CaCl2 concentrations below 150 mM, αSyn reverses the channel's selectivity from anionic to cationic. Importantly, we find that the decrease in channel conductance upon its blockage by αSyn is hugely overcompensated by a favorable change in the electrostatic environment for calcium, making the blocked state orders-of-magnitude more selective for calcium and thus increasing its net flux. -Our findings with higher calcium concentrations also demonstrate that the phenomenon of "charge inversion" is taking place at the level of a single polypeptide chain. Measurements of ion selectivity of three VDAC isoforms in CaCl2 gradient show that VDAC3 exhibits the highest calcium permeability among them, followed by VDAC2 and VDAC1, thus pointing to isoform-dependent physiological function. Mutation of the E73 residue - VDAC1 purported calcium binding site - shows that there is no measurable effect of the mutation in either open or αSyn-blocked VDAC1 states. Our results confirm VDACs involvement in calcium signaling and reveal a new regulatory role of αSyn, with clear implications for both normal calcium signaling and PD-associated mitochondrial dysfunction.
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Affiliation(s)
- William M Rosencrans
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Vicente M Aguilella
- Laboratory of Molecular Biophysics, Department of Physics, Universitat Jaume I, Av. Vicent Sos Baynat s/n 12071, Castellón, Spain
| | - Tatiana K Rostovtseva
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, 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, MD, 20892, USA
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15
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Hoogerheide DP, Rostovtseva TK, Jacobs D, Gurnev PA, Bezrukov SM. Tunable Electromechanical Nanopore Trap Reveals Populations of Peripheral Membrane Protein Binding Conformations. ACS NANO 2021; 15:989-1001. [PMID: 33369404 PMCID: PMC9019845 DOI: 10.1021/acsnano.0c07672] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
We demonstrate that a naturally occurring nanopore, the voltage-dependent anion channel (VDAC) of the mitochondrion, can be used to electromechanically trap and interrogate proteins bound to a lipid surface at the single-molecule level. Electromechanically probing α-synuclein (αSyn), an intrinsically disordered neuronal protein intimately associated with Parkinson's pathology, reveals wide variation in the time required for individual proteins to unbind from the same membrane surface. The observed distributions of unbinding times span up to 3 orders of magnitude and depend strongly on the lipid composition of the membrane; surprisingly, lipid membranes to which αSyn binds weakly are most likely to contain subpopulations in which electromechanically driven unbinding is very slow. We conclude that unbinding of αSyn from the membrane surface depends not only on membrane binding affinity but also on the conformation adopted by an individual αSyn molecule on the membrane surface.
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Affiliation(s)
- David P. Hoogerheide
- Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899
- Corresponding author:
| | - Tatiana K. Rostovtseva
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892
| | - Daniel Jacobs
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892
| | - Philip A. Gurnev
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892
| | - Sergey M. Bezrukov
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892
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16
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Berezhkovskii AM, Bezrukov SM. Capturing single molecules by nanopores: measured times and thermodynamics. Phys Chem Chem Phys 2021; 23:1610-1615. [PMID: 33410847 PMCID: PMC8075107 DOI: 10.1039/d0cp04747c] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
In numerous nanopore sensing applications transient interruptions in ion current through single nanopores induced by capturing solute molecules are a source of information on how solutes interact with the nanopores. We show that the distribution of time spent by a single captured solute molecule in a nanopore is bimodal with the majority of capture events being too fast to be experimentally resolved. As a result, the exact mean durations of the event and inter-event interval are orders of magnitude shorter than their measured values. Moreover, the exact and measured mean durations have qualitatively different dependences on the molecule diffusivity. This leads to a formal contradiction with the thermodynamics of molecule partitioning between the bulk and the nanopore. Here we resolve this controversy. We also demonstrate that, surprisingly, the probability of finding a molecule in the nanopore, obtained from the ratio of the measured mean durations of the capture event and interevent interval, is essentially identical to the exact equilibrium thermodynamic probability.
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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, MD 20892, USA and Mathematical and Statistical Computing Laboratory, Office of Intramural Research, Center for Information Technology, National Institutes of Health, Bethesda, MD 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, MD 20892, USA
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17
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Sander P, Gudermann T, Schredelseker J. A Calcium Guard in the Outer Membrane: Is VDAC a Regulated Gatekeeper of Mitochondrial Calcium Uptake? Int J Mol Sci 2021; 22:ijms22020946. [PMID: 33477936 PMCID: PMC7833399 DOI: 10.3390/ijms22020946] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 01/12/2021] [Accepted: 01/14/2021] [Indexed: 12/15/2022] Open
Abstract
Already in the early 1960s, researchers noted the potential of mitochondria to take up large amounts of Ca2+. However, the physiological role and the molecular identity of the mitochondrial Ca2+ uptake mechanisms remained elusive for a long time. The identification of the individual components of the mitochondrial calcium uniporter complex (MCUC) in the inner mitochondrial membrane in 2011 started a new era of research on mitochondrial Ca2+ uptake. Today, many studies investigate mitochondrial Ca2+ uptake with a strong focus on function, regulation, and localization of the MCUC. However, on its way into mitochondria Ca2+ has to pass two membranes, and the first barrier before even reaching the MCUC is the outer mitochondrial membrane (OMM). The common opinion is that the OMM is freely permeable to Ca2+. This idea is supported by the presence of a high density of voltage-dependent anion channels (VDACs) in the OMM, forming large Ca2+ permeable pores. However, several reports challenge this idea and describe VDAC as a regulated Ca2+ channel. In line with this idea is the notion that its Ca2+ selectivity depends on the open state of the channel, and its gating behavior can be modified by interaction with partner proteins, metabolites, or small synthetic molecules. Furthermore, mitochondrial Ca2+ uptake is controlled by the localization of VDAC through scaffolding proteins, which anchor VDAC to ER/SR calcium release channels. This review will discuss the possibility that VDAC serves as a physiological regulator of mitochondrial Ca2+ uptake in the OMM.
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Affiliation(s)
- Paulina Sander
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, LMU Munich, 80336 Munich, Germany; (P.S.); (T.G.)
| | - Thomas Gudermann
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, LMU Munich, 80336 Munich, Germany; (P.S.); (T.G.)
- Deutsches Zentrum für Herz-Kreislauf-Forschung, Partner Site Munich Heart Alliance, Munich, Germany
| | - Johann Schredelseker
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, LMU Munich, 80336 Munich, Germany; (P.S.); (T.G.)
- Deutsches Zentrum für Herz-Kreislauf-Forschung, Partner Site Munich Heart Alliance, Munich, Germany
- Correspondence: ; Tel.: +49-(0)89-2180-73831
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18
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High-Resolution Respirometry Reveals MPP + Mitochondrial Toxicity Mechanism in a Cellular Model of Parkinson's Disease. Int J Mol Sci 2020; 21:ijms21217809. [PMID: 33105548 PMCID: PMC7659480 DOI: 10.3390/ijms21217809] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Revised: 10/19/2020] [Accepted: 10/20/2020] [Indexed: 12/21/2022] Open
Abstract
MPP+ is the active metabolite of MPTP, a molecule structurally similar to the herbicide Paraquat, known to injure the dopaminergic neurons of the nigrostriatal system in Parkinson’s disease models. Within the cells, MPP+ accumulates in mitochondria where it inhibits complex I of the electron transport chain, resulting in ATP depletion and neuronal impairment/death. So far, MPP+ is recognized as a valuable tool to mimic dopaminergic degeneration in various cell lines. However, despite a large number of studies, a detailed characterization of mitochondrial respiration in neuronal cells upon MPP+ treatment is still missing. By using high-resolution respirometry, we deeply investigated oxygen consumption related to each respiratory state in differentiated neuroblastoma cells exposed to the neurotoxin. Our results indicated the presence of extended mitochondrial damage at the inner membrane level, supported by increased LEAK respiration, and a drastic drop in oxygen flow devoted to ADP phosphorylation in respirometry measurements. Furthermore, prior to complex I inhibition, an enhancement of complex II activity was observed, suggesting the occurrence of some compensatory effect. Overall our findings provide a mechanistic insight on the mitochondrial toxicity mediated by MPP+, relevant for the standardization of studies that employ this neurotoxin as a disease model.
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19
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Rovini A, Gurnev PA, Beilina A, Queralt-Martín M, Rosencrans W, Cookson MR, Bezrukov SM, Rostovtseva TK. Molecular mechanism of olesoxime-mediated neuroprotection through targeting α-synuclein interaction with mitochondrial VDAC. Cell Mol Life Sci 2020; 77:3611-3626. [PMID: 31760463 PMCID: PMC7244372 DOI: 10.1007/s00018-019-03386-w] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 10/23/2019] [Accepted: 11/13/2019] [Indexed: 01/03/2023]
Abstract
An intrinsically disordered neuronal protein α-synuclein (αSyn) is known to cause mitochondrial dysfunction, contributing to loss of dopaminergic neurons in Parkinson's disease. Through yet poorly defined mechanisms, αSyn crosses mitochondrial outer membrane and targets respiratory complexes leading to bioenergetics defects. Here, using neuronally differentiated human cells overexpressing wild-type αSyn, we show that the major metabolite channel of the outer membrane, the voltage-dependent anion channel (VDAC), is a pathway for αSyn translocation into the mitochondria. Importantly, the neuroprotective cholesterol-like synthetic compound olesoxime inhibits this translocation. By applying complementary electrophysiological and biophysical approaches, we provide mechanistic insights into the interplay between αSyn, VDAC, and olesoxime. Our data suggest that olesoxime interacts with VDAC β-barrel at the lipid-protein interface thus hindering αSyn translocation through the VDAC pore and affecting VDAC voltage gating. We propose that targeting αSyn translocation through VDAC could represent a key mechanism for the development of new neuroprotective strategies.
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Affiliation(s)
- Amandine Rovini
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 9000 Rockville Pike, Bldg. 29B, Room 1G09, Bethesda, MD, 20892-0924, USA
- Department of Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - Philip A Gurnev
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 9000 Rockville Pike, Bldg. 29B, Room 1G09, Bethesda, MD, 20892-0924, USA
| | - Alexandra Beilina
- Cell Biology and Gene Expression Section, Laboratory of Neurogenetics, National Institute of Aging, National Institutes of Health, Bethesda, MD, 20892, USA
| | - María Queralt-Martín
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 9000 Rockville Pike, Bldg. 29B, Room 1G09, Bethesda, MD, 20892-0924, USA
| | - William Rosencrans
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 9000 Rockville Pike, Bldg. 29B, Room 1G09, Bethesda, MD, 20892-0924, USA
- Colgate University, Hamilton, NY, 13346, USA
| | - Mark R Cookson
- Cell Biology and Gene Expression Section, Laboratory of Neurogenetics, National Institute of Aging, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Sergey M Bezrukov
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 9000 Rockville Pike, Bldg. 29B, Room 1G09, Bethesda, MD, 20892-0924, USA
| | - Tatiana K Rostovtseva
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 9000 Rockville Pike, Bldg. 29B, Room 1G09, Bethesda, MD, 20892-0924, USA.
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20
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Hoogerheide DP, Gurnev PA, Rostovtseva TK, Bezrukov SM. Effect of a post-translational modification mimic on protein translocation through a nanopore. NANOSCALE 2020; 12:11070-11078. [PMID: 32400834 PMCID: PMC7350168 DOI: 10.1039/d0nr01577f] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Post-translational modifications (PTMs) of proteins are recognized as crucial components of cell signaling pathways through modulating folding, altering stability, changing interactions with ligands, and, therefore, serving multiple regulatory functions. PTMs occur as covalent modifications of the protein's amino acid side chains or the length and composition of their termini. Here we study the functional consequences of PTMs for α-synuclein (αSyn) interactions with the nanopore of the voltage-dependent anion channel (VDAC) of the outer mitochondrial membrane. PTMs were mimicked by a divalent Alexa Fluor 488 sidechain attached separately at two positions on the αSyn C-terminus. Using single-channel reconstitution into planar lipid membranes, we find that such modifications change interactions drastically in both efficiency of VDAC inhibition by αSyn and its translocation through the VDAC nanopore. Analysis of the on/off kinetics in terms of an interaction "quasipotential" allows the positions of the C-terminal modifications to be determined with an accuracy of about three residues. Moreover, our results uncover a previously unobserved mechanism by which cytosolic proteins control β-barrel channels and thus a new regulatory function for PTMs.
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Affiliation(s)
- David P Hoogerheide
- Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA.
| | - Philip A Gurnev
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Tatiana K Rostovtseva
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 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, MD 20892, USA
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21
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Kanwar P, Samtani H, Sanyal SK, Srivastava AK, Suprasanna P, Pandey GK. VDAC and its interacting partners in plant and animal systems: an overview. Crit Rev Biotechnol 2020; 40:715-732. [PMID: 32338074 DOI: 10.1080/07388551.2020.1756214] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Molecular trafficking between different subcellular compartments is the key for normal cellular functioning. Voltage-dependent anion channels (VDACs) are small-sized proteins present in the outer mitochondrial membrane, which mediate molecular trafficking between mitochondria and cytoplasm. The conductivity of VDAC is dependent on the transmembrane voltage, its oligomeric state and membrane lipids. VDAC acts as a convergence point to a diverse variety of mitochondrial functions as well as cell survival. This functional diversity is attained due to their interaction with a plethora of proteins inside the cell. Although, there are hints toward functional conservation/divergence between animals and plants; knowledge about the functional role of the VDACs in plants is still limited. We present here a comparative overview to provide an integrative picture of the interactions of VDAC with different proteins in both animals and plants. Also discussed are their physiological functions from the perspective of cellular movements, signal transduction, cellular fate, disease and development. This in-depth knowledge of the biological importance of VDAC and its interacting partner(s) will assist us to explore their function in the applied context in both plant and animal.
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Affiliation(s)
- Poonam Kanwar
- Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi, India
| | - Harsha Samtani
- Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi, India
| | - Sibaji K Sanyal
- Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi, India
| | - Ashish K Srivastava
- Nuclear Agriculture and Biotechnology Division, Bhabha Atomic Research Centre, Mumbai, India
| | - Penna Suprasanna
- Nuclear Agriculture and Biotechnology Division, Bhabha Atomic Research Centre, Mumbai, India
| | - Girdhar K Pandey
- Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi, India
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22
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Vicario M, Cieri D, Vallese F, Catoni C, Barazzuol L, Berto P, Grinzato A, Barbieri L, Brini M, Calì T. A split-GFP tool reveals differences in the sub-mitochondrial distribution of wt and mutant alpha-synuclein. Cell Death Dis 2019; 10:857. [PMID: 31719530 PMCID: PMC6851186 DOI: 10.1038/s41419-019-2092-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 10/11/2019] [Accepted: 10/28/2019] [Indexed: 01/01/2023]
Abstract
Parkinson’s disease (PD), the second most common neurodegenerative disorder, is characterized by dopaminergic neuronal loss that initiates in the substantia nigra pars compacta and by the formation of intracellular inclusions mainly constituted by aberrant α-synuclein (α-syn) deposits known as Lewy bodies. Most cases of PD are sporadic, but about 10% are familial, among them those caused by mutations in SNCA gene have an autosomal dominant transmission. SNCA encodes α-syn, a small 140-amino acids protein that, under physiological conditions, is mainly localized at the presynaptic terminals. It is prevalently cytosolic, but its presence has been reported in the nucleus, in the mitochondria and, more recently, in the mitochondria-associated ER membranes (MAMs). Whether different cellular localizations may reflect specific α-syn activities is presently unclear and its action at mitochondrial level is still a matter of debate. Mounting evidence supports a role for α-syn in several mitochondria-derived activities, among which maintenance of mitochondrial morphology and modulation of complex I and ATP synthase activity. α-syn has been proposed to localize at the outer membrane (OMM), in the intermembrane space (IMS), at the inner membrane (IMM) and in the mitochondrial matrix, but a clear and comparative analysis of the sub-mitochondrial localization of WT and mutant α-syn is missing. Furthermore, the reasons for this spread sub-mitochondrial localization under physiological and pathological circumstances remain elusive. In this context, we decided to selectively monitor the sub-mitochondrial distribution of the WT and PD-related α-syn mutants A53T and A30P by taking advantage from a bimolecular fluorescence complementation (BiFC) approach. We also investigated whether cell stress could trigger α-syn translocation within the different mitochondrial sub-compartments and whether PD-related mutations could impinge on it. Interestingly, the artificial targeting of α-syn WT (but not of the mutants) to the mitochondrial matrix impacts on ATP production, suggesting a potential role within this compartment.
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Affiliation(s)
- Mattia Vicario
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Domenico Cieri
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Francesca Vallese
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | | | - Lucia Barazzuol
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Paola Berto
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | | | - Laura Barbieri
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Marisa Brini
- Department of Biology, University of Padova, Padova, Italy.
| | - Tito Calì
- Department of Biomedical Sciences, University of Padova, Padova, Italy. .,Padova Neuroscience Center (PNC), University of Padova, Padova, Italy.
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23
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Botello-Smith WM, Jiang W, Zhang H, Ozkan AD, Lin YC, Pham CN, Lacroix JJ, Luo Y. A mechanism for the activation of the mechanosensitive Piezo1 channel by the small molecule Yoda1. Nat Commun 2019; 10:4503. [PMID: 31582801 PMCID: PMC6776524 DOI: 10.1038/s41467-019-12501-1] [Citation(s) in RCA: 107] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 08/09/2019] [Indexed: 12/19/2022] Open
Abstract
Mechanosensitive Piezo1 and Piezo2 channels transduce various forms of mechanical forces into cellular signals that play vital roles in many important biological processes in vertebrate organisms. Besides mechanical forces, Piezo1 is selectively activated by micromolar concentrations of the small molecule Yoda1 through an unknown mechanism. Here, using a combination of all-atom molecular dynamics simulations, calcium imaging and electrophysiology, we identify an allosteric Yoda1 binding pocket located in the putative mechanosensory domain, approximately 40 Å away from the central pore. Our simulations further indicate that the presence of the agonist correlates with increased tension-induced motions of the Yoda1-bound subunit. Our results suggest a model wherein Yoda1 acts as a molecular wedge, facilitating force-induced conformational changes, effectively lowering the channel's mechanical threshold for activation. The identification of an allosteric agonist binding site in Piezo1 channels will pave the way for the rational design of future Piezo modulators with clinical value.
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Affiliation(s)
- Wesley M Botello-Smith
- College of Pharmacy, Western University of Health Sciences, 309 E. Second St, Pomona, CA, 91766, USA
| | - Wenjuan Jiang
- College of Pharmacy, Western University of Health Sciences, 309 E. Second St, Pomona, CA, 91766, USA
| | - Han Zhang
- College of Pharmacy, Western University of Health Sciences, 309 E. Second St, Pomona, CA, 91766, USA
| | - Alper D Ozkan
- Graduate College of Biomedical Sciences, Western University of Health Sciences, 309 E. Second St, Pomona, CA, 91766, USA
| | - Yi-Chun Lin
- College of Pharmacy, Western University of Health Sciences, 309 E. Second St, Pomona, CA, 91766, USA
| | - Christine N Pham
- College of Pharmacy, Western University of Health Sciences, 309 E. Second St, Pomona, CA, 91766, USA
| | - Jérôme J Lacroix
- Graduate College of Biomedical Sciences, Western University of Health Sciences, 309 E. Second St, Pomona, CA, 91766, USA.
| | - Yun Luo
- College of Pharmacy, Western University of Health Sciences, 309 E. Second St, Pomona, CA, 91766, USA.
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24
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Vasili E, Dominguez-Meijide A, Outeiro TF. Spreading of α-Synuclein and Tau: A Systematic Comparison of the Mechanisms Involved. Front Mol Neurosci 2019; 12:107. [PMID: 31105524 PMCID: PMC6494944 DOI: 10.3389/fnmol.2019.00107] [Citation(s) in RCA: 75] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2019] [Accepted: 04/09/2019] [Indexed: 01/01/2023] Open
Abstract
Alzheimer's disease (AD) and Parkinson's disease (PD) are age-associated neurodegenerative disorders characterized by the misfolding and aggregation of alpha-synuclein (aSyn) and tau, respectively. The coexistence of aSyn and tau aggregates suggests a strong overlap between tauopathies and synucleinopathies. Interestingly, misfolded forms of aSyn and tau can propagate from cell to cell, and throughout the brain, thereby templating the misfolding of native forms of the proteins. The exact mechanisms involved in the propagation of the two proteins show similarities, and are reminiscent of the spreading characteristic of prion diseases. Recently, several models were developed to study the spreading of aSyn and tau. Here, we discuss the mechanisms involved, the similarities and differences between the spreading of the two proteins and that of the prion protein, and the different cell and animal models used for studying these processes. Ultimately, a deeper understanding of the molecular mechanisms involved may lead to the identification of novel targets for therapeutic intervention in a variety of devastating neurodegenerative diseases.
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Affiliation(s)
- Eftychia Vasili
- Department of Experimental Neurodegeneration, Center for Nanoscale Microscopy and Molecular Physiology of the Brain, Center for Biostructural Imaging of Neurodegeneration, University Medical Center Goettingen, Goettingen, Germany
| | - Antonio Dominguez-Meijide
- Department of Experimental Neurodegeneration, Center for Nanoscale Microscopy and Molecular Physiology of the Brain, Center for Biostructural Imaging of Neurodegeneration, University Medical Center Goettingen, Goettingen, Germany
| | - Tiago Fleming Outeiro
- Department of Experimental Neurodegeneration, Center for Nanoscale Microscopy and Molecular Physiology of the Brain, Center for Biostructural Imaging of Neurodegeneration, University Medical Center Goettingen, Goettingen, Germany.,Max Planck Institute for Experimental Medicine, Goettingen, Germany.,The Medical School, Institute of Neuroscience, Newcastle University, Newcastle Upon Tyne, United Kingdom
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25
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Probing Membrane Association of α-Synuclein Domains with VDAC Nanopore Reveals Unexpected Binding Pattern. Sci Rep 2019; 9:4580. [PMID: 30872688 PMCID: PMC6418135 DOI: 10.1038/s41598-019-40979-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Accepted: 02/25/2019] [Indexed: 11/09/2022] Open
Abstract
It is well established that α-synuclein (α-syn) binding from solution to the surface of membranes composed of negatively charged and/or non-lamellar lipids can be characterized by equilibrium dissociation constants of tens of micromolar. Previously, we have found that a naturally occurring nanopore of the mitochondrial voltage-dependent anion channel (VDAC), reconstituted into planar bilayers of a plant-derived lipid, responds to α-syn at nanomolar solution concentrations. Here, using lipid mixtures that mimic the composition of mitochondrial outer membranes, we show that functionally important binding does indeed take place in the nanomolar range. We demonstrate that the voltage-dependent rate at which a membrane-embedded VDAC nanopore captures α-syn is a strong function of membrane composition. Comparison of the nanopore results with those obtained by the bilayer overtone analysis of membrane binding demonstrates a pronounced correlation between the two datasets. The stronger the binding, the larger the on-rate, but with some notable exceptions. This leads to a tentative model of α-syn-membrane interactions, which assigns different lipid-dependent roles to the N- and C-terminal domains of α-syn accounting for both electrostatic and hydrophobic effects. As a result, the rate of α-syn capture by the nanopore is not simply proportional to the α-syn concentration on the membrane surface but found to be sensitive to the specific interactions of each domain with the membrane and nanopore.
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26
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Klepinin A, Ounpuu L, Mado K, Truu L, Chekulayev V, Puurand M, Shevchuk I, Tepp K, Planken A, Kaambre T. The complexity of mitochondrial outer membrane permeability and VDAC regulation by associated proteins. J Bioenerg Biomembr 2018; 50:339-354. [PMID: 29998379 PMCID: PMC6209068 DOI: 10.1007/s10863-018-9765-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 07/05/2018] [Indexed: 12/18/2022]
Abstract
Previous studies have shown that class II β-tubulin plays a key role in the regulation of oxidative phosphorylation (OXPHOS) in some highly differentiated cells, but its role in malignant cells has remained unclear. To clarify these aspects, we compared the bioenergetic properties of HL-1 murine sarcoma cells, murine neuroblastoma cells (uN2a) and retinoic acid - differentiated N2a cells (dN2a). We examined the expression and possible co-localization of mitochondrial voltage dependent anion channel (VDAC) with hexokinase-2 (HK-2) and βII-tubulin, the role of depolymerized βII-tubuline and the effect of both proteins in the regulation of mitochondrial outer membrane (MOM) permeability. Our data demonstrate that neuroblastoma and sarcoma cells are prone to aerobic glycolysis, which is partially mediated by the presence of VDAC bound HK-2. Microtubule destabilizing (colchicine) and stabilizing (taxol) agents do not affect the MOM permeability for ADP in N2a and HL-1 cells. The obtained results show that βII-tubulin does not regulate the MOM permeability for adenine nucleotides in these cells. HL-1 and NB cells display comparable rates of ADP-activated respiration. It was also found that differentiation enhances the involvement of OXPHOS in N2a cells due to the rise in their mitochondrial reserve capacity. Our data support the view that the alteration of mitochondrial affinity for ADNs is one of the characteristic features of cancer cells. It can be concluded that the binding sites for tubulin and hexokinase within the large intermembrane protein supercomplex Mitochondrial Interactosome, could be different between muscle and cancer cells.
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Affiliation(s)
- Aleksandr Klepinin
- Laboratory of Bioenergetics, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618, Tallinn, Estonia
| | - Lyudmila Ounpuu
- Laboratory of Bioenergetics, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618, Tallinn, Estonia
| | - Kati Mado
- Laboratory of Bioenergetics, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618, Tallinn, Estonia
| | - Laura Truu
- Laboratory of Bioenergetics, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618, Tallinn, Estonia
| | - Vladimir Chekulayev
- Laboratory of Bioenergetics, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618, Tallinn, Estonia
| | - Marju Puurand
- Laboratory of Bioenergetics, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618, Tallinn, Estonia
| | - Igor Shevchuk
- Laboratory of Bioenergetics, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618, Tallinn, Estonia
| | - Kersti Tepp
- Laboratory of Bioenergetics, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618, Tallinn, Estonia
| | - Anu Planken
- Oncology and Hematology Clinic at the North Estonia Medical Centre, Tallinn, Estonia
| | - Tuuli Kaambre
- Laboratory of Bioenergetics, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618, Tallinn, Estonia.
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27
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Robertson JWF, Reiner JE. The Utility of Nanopore Technology for Protein and Peptide Sensing. Proteomics 2018; 18:e1800026. [PMID: 29952121 PMCID: PMC10935609 DOI: 10.1002/pmic.201800026] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 06/13/2018] [Indexed: 04/29/2024]
Abstract
Resistive pulse nanopore sensing enables label-free single-molecule analysis of a wide range of analytes. An increasing number of studies have demonstrated the feasibility and usefulness of nanopore sensing for protein and peptide characterization. Nanopores offer the potential to study a variety of protein-related phenomena that includes unfolding kinetics, differences in unfolding pathways, protein structure stability, and free-energy profiles of DNA-protein and RNA-protein binding. In addition to providing a tool for fundamental protein characterization, nanopores have also been used as highly selective protein detectors in various solution mixtures and conditions. This review highlights these and other developments in the area of nanopore-based protein and peptide detection.
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Affiliation(s)
- Joseph W F Robertson
- Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA
| | - Joseph E Reiner
- Department of Physics, Virginia Commonwealth University, Richmond, VA, 23284, USA
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28
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Ding H, Xiong Y, Sun J, Chen C, Gao J, Xu H. Asiatic Acid Prevents Oxidative Stress and Apoptosis by Inhibiting the Translocation of α-Synuclein Into Mitochondria. Front Neurosci 2018; 12:431. [PMID: 30002614 PMCID: PMC6031891 DOI: 10.3389/fnins.2018.00431] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Accepted: 06/07/2018] [Indexed: 01/08/2023] Open
Abstract
The association of α-synuclein (α-syn) with mitochondria occurs through interaction with mitochondrial complex I. Defects in this protein have been linked to the pathogenesis of Parkinson disease (PD). Overexpression of α-synuclein in cells has been suggested to cause elevations in mitochondrial oxidant radicals and structural and functional abnormalities in mitochondria. Asiatic acid (AA), a triterpenoid, is an antioxidant that is used for depression, and we have shown that pretreatment with AA can prevent PD-like damage, but its therapeutic effects in PD and mechanism remain unknown. In this study, we found that 0.5–2 mg AA/100 g diet significantly improves climbing ability in drosophila and extends their life-span—effects that we attributed to its antioxidant properties. AA also protected mitochondria against oxidative stress and apoptosis in a rotenone-induced cellular model. In an isolated mitochondria model, AA attenuated the decline in mitochondrial membrane potential that was induced by α-syn. Consequently, AA maintained membrane integrity and ATP production. Finally, we demonstrated that AA protects by blocking the translocation of α-syn into mitochondria. Our results suggest that mitochondria are crucial in PD and that AA is an excellent candidate for the prevention and therapy of this disease.
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Affiliation(s)
- Hongqun Ding
- Department of Clinical Laboratory Diagnostics, School of Medicine, Jiangsu University, Zhenjiang, China
| | - Yuyun Xiong
- Department of Clinical Laboratory, Affiliated Hospital of Jiangsu University, Zhenjiang, China
| | - Jing Sun
- Department of Medicinal Pharmacy, School of Pharmacy, Jiangsu University, Zhenjiang, China
| | - Chen Chen
- Department of Medicinal Pharmacy, School of Pharmacy, Jiangsu University, Zhenjiang, China
| | - Jing Gao
- Department of Medicinal Pharmacy, School of Pharmacy, Jiangsu University, Zhenjiang, China
| | - Huaxi Xu
- Department of Clinical Laboratory Diagnostics, School of Medicine, Jiangsu University, Zhenjiang, China
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29
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Vicario M, Cieri D, Brini M, Calì T. The Close Encounter Between Alpha-Synuclein and Mitochondria. Front Neurosci 2018; 12:388. [PMID: 29930495 PMCID: PMC5999749 DOI: 10.3389/fnins.2018.00388] [Citation(s) in RCA: 88] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Accepted: 05/22/2018] [Indexed: 01/02/2023] Open
Abstract
The presynaptic protein alpha-synuclein (α-syn) is unequivocally linked to the development of Parkinson’s disease (PD). Not only it is the major component of amyloid fibrils found in Lewy bodies but mutations and duplication/triplication in its gene are responsible for the onset of familial autosomal dominant forms of PD. Nevertheless, the precise mechanisms leading to neuronal degeneration are not fully understood. Several lines of evidence suggest that impaired autophagy clearance and mitochondrial dysfunctions such as bioenergetics and calcium handling defects and alteration in mitochondrial morphology might play a pivotal role in the etiology and progression of PD, and indicate the intriguing possibility that α-syn could be involved in the control of mitochondrial function both in physiological and pathological conditions. In favor of this, it has been shown that a fraction of cellular α-syn can selectively localize to mitochondrial sub-compartments upon specific stimuli, highlighting possible novel routes for α-syn action. A plethora of mitochondrial processes, including cytochrome c release, calcium homeostasis, control of mitochondrial membrane potential and ATP production, is directly influenced by α-syn. Eventually, α-syn localization within mitochondria may also account for its aggregation state, making the α-syn/mitochondria intimate relationship a potential key for the understanding of PD pathogenesis. Here, we will deeply survey the recent literature in the field by focusing our attention on the processes directly controlled by α-syn within mitochondrial sub-compartments and its potential partners providing possible hints for future therapeutic targets.
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Affiliation(s)
- Mattia Vicario
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Domenico Cieri
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Marisa Brini
- Department of Biology, University of Padova, Padova, Italy
| | - Tito Calì
- Department of Biomedical Sciences, University of Padova, Padova, Italy.,Padova Neuroscience Center, University of Padova, Padova, Italy
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30
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Rostovtseva TK, Gurnev PA, Hoogerheide DP, Rovini A, Sirajuddin M, Bezrukov SM. Sequence diversity of tubulin isotypes in regulation of the mitochondrial voltage-dependent anion channel. J Biol Chem 2018; 293:10949-10962. [PMID: 29777059 DOI: 10.1074/jbc.ra117.001569] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 05/16/2018] [Indexed: 12/31/2022] Open
Abstract
The microtubule protein tubulin is a heterodimer comprising α/β subunits, in which each subunit features multiple isotypes in vertebrates. For example, seven α-tubulin and eight β-tubulin isotypes in the human tubulin gene family vary mostly in the length and primary sequence of the disordered anionic carboxyl-terminal tails (CTTs). The biological reason for such sequence diversity remains a topic of vigorous enquiry. Here, we demonstrate that it may be a key feature of tubulin's role in regulation of the permeability of the mitochondrial outer membrane voltage-dependent anion channel (VDAC). Using recombinant yeast α/β-tubulin constructs with α-CTTs, β-CTTs, or both from various human tubulin isotypes, we probed their interactions with VDAC reconstituted into planar lipid bilayers. A comparative study of the blockage kinetics revealed that either α-CTTs or β-CTTs block the VDAC pore and that the efficiency of blockage by individual CTTs spans 2 orders of magnitude, depending on the CTT isotype. β-Tubulin constructs, notably β3, blocked VDAC most effectively. We quantitatively described these experimental results using a physical model that accounted only for the number and distribution of charges in the CTT, and not for the interactions between specific residues on the CTT and VDAC pore. Based on these results, we speculate that the effectiveness of VDAC regulation by tubulin depends on the predominant tubulin isotype in a cell. Consequently, the fluxes of ATP/ADP through the channel could vary significantly, depending on the isotype, thus suggesting an intriguing link between VDAC regulation and the diversity of tubulin isotypes present in vertebrates.
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Affiliation(s)
- Tatiana K Rostovtseva
- From the Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892-0924,
| | - Philip A Gurnev
- From the Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892-0924
| | - David P Hoogerheide
- the Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, and
| | - Amandine Rovini
- From the Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892-0924
| | | | - Sergey M Bezrukov
- From the Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892-0924
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31
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Hoogerheide DP, Gurnev PA, Rostovtseva TK, Bezrukov SM. Real-Time Nanopore-Based Recognition of Protein Translocation Success. Biophys J 2018; 114:772-776. [PMID: 29338842 DOI: 10.1016/j.bpj.2017.12.019] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 12/05/2017] [Accepted: 12/15/2017] [Indexed: 01/06/2023] Open
Abstract
A growing number of new technologies are supported by a single- or multi-nanopore architecture for capture, sensing, and delivery of polymeric biomolecules. Nanopore-based single-molecule DNA sequencing is the premier example. This method relies on the uniform linear charge density of DNA, so that each DNA strand is overwhelmingly likely to pass through the nanopore and across the separating membrane. For disordered peptides, folded proteins, or block copolymers with heterogeneous charge densities, by contrast, translocation is not assured, and additional strategies to monitor the progress of the polymer molecule through a nanopore are required. Here, we demonstrate a single-molecule method for direct, model-free, real-time monitoring of the translocation of a disordered, heterogeneously charged polypeptide through a nanopore. The crucial elements are two "selectivity tags"-regions of different but uniform charge density-at the ends of the polypeptide. These affect the selectivity of the nanopore differently and enable discrimination between polypeptide translocation and retraction. Our results demonstrate exquisite sensitivity of polypeptide translocation to applied transmembrane potential and prove the principle that nanopore selectivity reports on biopolymer substructure. We anticipate that the selectivity tag technique will be broadly applicable to nanopore-based protein detection, analysis, and separation technologies, and to the elucidation of protein translocation processes in normal cellular function and in disease.
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Affiliation(s)
- David P Hoogerheide
- Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland.
| | - Philip A Gurnev
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland
| | - Tatiana K Rostovtseva
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland
| | - Sergey M Bezrukov
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland.
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32
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Boukhet M, König NF, Ouahabi AA, Baaken G, Lutz JF, Behrends JC. Translocation of Precision Polymers through Biological Nanopores. Macromol Rapid Commun 2017; 38. [PMID: 29144014 DOI: 10.1002/marc.201700680] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 10/25/2017] [Indexed: 11/10/2022]
Abstract
Nanopore analysis, which is, currently, chiefly used for DNA sequencing, is also an appealing technique for characterizing abiotic polymers. As a first step toward this goal, nanopore detection of non-natural monodispersed poly(phosphodiester)s as candidate backbone structures is reported herein. Two model homopolymers containing phosphopropyl repeat units (i.e., 56 or 104 r.u.) and a short thymidine nucleotide sequence are analyzed in the present work. They are tested in two different biological nanopores, α-hemolysin from Staphylococcus aureus, and aerolysin from Aeromonas hydrophila. These recordings are performed in aqueous medium at different KCl concentrations and various driving voltages. The data show a complex interaction with evidence for voltage dependence and threading, and underline the influence of the molecular structure and orientation of the precision poly(phosphodiester)s on the observed residual current signal as well as on the translocation dynamics. In particular, they suggest a dominant entropic contribution due to the high flexibility of the phosphodiester homopolymer.
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Affiliation(s)
- Mordjane Boukhet
- Ionera Technologies GmbH, Hermann-Herder-Str. 7, 79104, Freiburg, Germany
| | - Niklas Felix König
- CNRS, Institut Charles Sadron UPR22, Université de Strasbourg, 23 Rue du Loess, 67034, Strasbourg Cedex 2, France
| | - Abdelaziz Al Ouahabi
- CNRS, Institut Charles Sadron UPR22, Université de Strasbourg, 23 Rue du Loess, 67034, Strasbourg Cedex 2, France
| | - Gerhard Baaken
- Ionera Technologies GmbH, Hermann-Herder-Str. 7, 79104, Freiburg, Germany
| | - Jean-François Lutz
- CNRS, Institut Charles Sadron UPR22, Université de Strasbourg, 23 Rue du Loess, 67034, Strasbourg Cedex 2, France
| | - Jan C Behrends
- Laboratory for Membrane Physiology and Technology, Department of Physiology, Faculty of Medicine, University of Freiburg, Hermann-Herder-Str. 7, 79104, Freiburg, Germany.,Freiburg Materials Research Centre, University of Freiburg, Stefan-Meier-Str. 19, 79104, Freiburg, Germany.,Freiburg Centre for Interactive Materials and Bioinspired Technologies, University of Freiburg, Georges-Köhler-Allee 105, 79110, Freiburg, Germany
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33
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Miranda WE, Ngo VA, Perissinotti LL, Noskov SY. Computational membrane biophysics: From ion channel interactions with drugs to cellular function. BIOCHIMICA ET BIOPHYSICA ACTA. PROTEINS AND PROTEOMICS 2017; 1865:1643-1653. [PMID: 28847523 PMCID: PMC5764198 DOI: 10.1016/j.bbapap.2017.08.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2017] [Revised: 08/16/2017] [Accepted: 08/16/2017] [Indexed: 12/16/2022]
Abstract
The rapid development of experimental and computational techniques has changed fundamentally our understanding of cellular-membrane transport. The advent of powerful computers and refined force-fields for proteins, ions, and lipids has expanded the applicability of Molecular Dynamics (MD) simulations. A myriad of cellular responses is modulated through the binding of endogenous and exogenous ligands (e.g. neurotransmitters and drugs, respectively) to ion channels. Deciphering the thermodynamics and kinetics of the ligand binding processes to these membrane proteins is at the heart of modern drug development. The ever-increasing computational power has already provided insightful data on the thermodynamics and kinetics of drug-target interactions, free energies of solvation, and partitioning into lipid bilayers for drugs. This review aims to provide a brief summary about modeling approaches to map out crucial binding pathways with intermediate conformations and free-energy surfaces for drug-ion channel binding mechanisms that are responsible for multiple effects on cellular functions. We will discuss post-processing analysis of simulation-generated data, which are then transformed to kinetic models to better understand the molecular underpinning of the experimental observables under the influence of drugs or mutations in ion channels. This review highlights crucial mathematical frameworks and perspectives on bridging different well-established computational techniques to connect the dynamics and timescales from all-atom MD and free energy simulations of ion channels to the physiology of action potentials in cellular models. This article is part of a Special Issue entitled: Biophysics in Canada, edited by Lewis Kay, John Baenziger, Albert Berghuis and Peter Tieleman.
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Affiliation(s)
- Williams E Miranda
- Centre for Molecular Simulations, Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Van A Ngo
- Centre for Molecular Simulations, Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Laura L Perissinotti
- Centre for Molecular Simulations, Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Sergei Yu Noskov
- Centre for Molecular Simulations, Department of Biological Sciences, University of Calgary, Calgary, AB, Canada.
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34
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Watanabe H, Gubbiotti A, Chinappi M, Takai N, Tanaka K, Tsumoto K, Kawano R. Analysis of Pore Formation and Protein Translocation Using Large Biological Nanopores. Anal Chem 2017; 89:11269-11277. [DOI: 10.1021/acs.analchem.7b01550] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Hirokazu Watanabe
- Department
of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan
| | - Alberto Gubbiotti
- Department
of Mechanical and Aerospace Engineering, Sapienza University of Rome, Via Eudossiana 18, Rome 00184, Italy
| | - Mauro Chinappi
- Department
of Industrial Engineering, University of Rome Tor Vergata, Via
del Politecnico 1, Rome 00133, Italy
| | - Natsumi Takai
- Department
of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan
| | - Koji Tanaka
- Department
of Chemistry and Biotechnology, School of Engineering, The University of Tokyo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Kouhei Tsumoto
- Department
of Chemistry and Biotechnology, School of Engineering, The University of Tokyo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Ryuji Kawano
- Department
of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan
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35
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Berezhkovskii AM, Dagdug L, Bezrukov SM. First passage, looping, and direct transition in expanding and narrowing tubes: Effects of the entropy potential. J Chem Phys 2017; 147:134104. [PMID: 28987083 DOI: 10.1063/1.4993129] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
We study transitions of diffusing particles between the left and right ends of expanding and narrowing conical tubes. In an expanding tube, such transitions occur faster than in the narrowing tube of the same length and radius variation rate. This happens because the entropy potential pushes the particle towards the wide tube end, thus accelerating the transitions in the expanding tube and slowing them down in the narrowing tube. To gain deeper insight into how the transitions occur, we divide each trajectory into the direct-transit and looping segments. The former is the final part of the trajectory, where the particle starting from the left tube end goes to the right end without returning to the left one. The rest of the trajectory is the looping segment, where the particle, starting from the left tube end, returns to this end again and again until the direct transition happens. Our focus is on the durations of the two segments and their sum, which is the duration of the particle first passage between the left and right ends of the tube. We approach the problem using the one-dimensional description of the particle diffusion along the tube axis in terms of the modified Fick-Jacobs equation. This allows us to derive analytical expressions for the Laplace transforms of the probability densities of the first-passage, direct-transit, and looping times, which we use to find the mean values of these random variables. Our results show that the direct transits are independent of the entropy potential and occur as in free diffusion. However, this "free diffusion" occurs with the effective diffusivity entering the modified Fick-Jacobs equation, which is smaller than the particle diffusivity in a cylindrical tube. This is the only way how the varying tube geometry manifests itself in the direct transits. Since direct-transit times are direction-independent, the difference in the first-passage times in the tubes of the two types is due to the difference in the durations of the looping segments in the expanding and narrowing tubes. Obtained analytical results are supported by three-dimensional Brownian dynamics simulations.
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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
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36
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Berezhkovskii AM, Dagdug L, Bezrukov SM. A new insight into diffusional escape from a biased cylindrical trap. J Chem Phys 2017; 147:104103. [PMID: 28915752 DOI: 10.1063/1.5002127] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Recent experiments with single biological nanopores, as well as single-molecule fluorescence spectroscopy and pulling studies of protein and nucleic acid folding raised a number of questions that stimulated theoretical and computational investigations of barrier crossing dynamics. The present paper addresses a closely related problem focusing on trajectories of Brownian particles that escape from a cylindrical trap in the presence of a force F parallel to the cylinder axis. To gain new insights into the escape dynamics, we analyze the "fine structure" of these trajectories. Specifically, we divide trajectories into two segments: a looping segment, when a particle unsuccessfully tries to escape returning to the trap bottom again and again, and a direct-transit segment, when it finally escapes moving without touching the bottom. Analytical expressions are derived for the Laplace transforms of the probability densities of the durations of the two segments. These expressions are used to find the mean looping and direct-transit times as functions of the biasing force F. It turns out that the force-dependences of the two mean times are qualitatively different. The mean looping time monotonically increases as F decreases, approaching exponential F-dependence at large negative forces pushing the particle towards the trap bottom. In contrast to this intuitively appealing behavior, the mean direct-transit time shows rather counterintuitive behavior: it decreases as the force magnitude, |F|, increases independently of whether the force pushes the particles to the trap bottom or to the exit from the trap, having a maximum at F = 0.
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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
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37
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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.
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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
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38
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Rostovtseva TK, Hoogerheide DP, Rovini A, Bezrukov SM. Lipids in Regulation of the Mitochondrial Outer Membrane Permeability, Bioenergetics, and Metabolism. ACTA ACUST UNITED AC 2017. [DOI: 10.1007/978-3-319-55539-3_8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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