201
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Mitra AK. Visualization of biological macromolecules at near-atomic resolution: cryo-electron microscopy comes of age. Acta Crystallogr F Struct Biol Commun 2019; 75:3-11. [PMID: 30605120 PMCID: PMC6317457 DOI: 10.1107/s2053230x18015133] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 10/26/2018] [Indexed: 11/11/2022] Open
Abstract
Structural biology is going through a revolution as a result of transformational advances in the field of cryo-electron microscopy (cryo-EM) driven by the development of direct electron detectors and ultrastable electron microscopes. High-resolution cryo-EM images of isolated biomolecules (single particles) suspended in a thin layer of vitrified buffer are subjected to powerful image-processing algorithms, enabling near-atomic resolution structures to be determined in unprecedented numbers. Prior to these advances, electron crystallography of two-dimensional crystals and helical assemblies of proteins had established the feasibility of atomic resolution structure determination using cryo-EM. Atomic resolution single-particle analysis, without the need for crystals, now promises to resolve problems in structural biology that were intractable just a few years ago.
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MESH Headings
- Algorithms
- Bibliometrics
- Cryoelectron Microscopy/history
- Cryoelectron Microscopy/instrumentation
- Cryoelectron Microscopy/methods
- Crystallography, X-Ray/history
- Crystallography, X-Ray/instrumentation
- Crystallography, X-Ray/methods
- Equipment Design/history
- History, 20th Century
- History, 21st Century
- Humans
- Image Processing, Computer-Assisted/statistics & numerical data
- Imaging, Three-Dimensional/instrumentation
- Imaging, Three-Dimensional/methods
- Macromolecular Substances/chemistry
- Macromolecular Substances/ultrastructure
- Microscopy, Electron, Transmission/history
- Microscopy, Electron, Transmission/instrumentation
- Microscopy, Electron, Transmission/methods
- Specimen Handling/instrumentation
- Specimen Handling/methods
- Vitrification
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Affiliation(s)
- Alok K. Mitra
- School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand
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202
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Zhou T, Gui L, Liu M, Li W, Hu P, Duarte DFC, Niu H, Chen L. Transcriptomic responses to low temperature stress in the Nile tilapia, Oreochromis niloticus. FISH & SHELLFISH IMMUNOLOGY 2019; 84:1145-1156. [PMID: 30408600 DOI: 10.1016/j.fsi.2018.10.023] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 10/03/2018] [Accepted: 10/07/2018] [Indexed: 06/08/2023]
Abstract
The Nile tilapia, Oreochromis niloticus, is a species of high economic value and extensively cultured. The limited stress tolerance of this species to a low temperature usually leads to mass mortality and great loss. Nevertheless, there is limited information on the molecular mechanisms underlying the susceptibility to low temperature in the tilapia. In this study, tilapia was treated at 28 °C to a lethal temperature of 8 °C by a gradual decrement. Transcriptomic response of the immune organ, kidney, in tilapia was characterized using RNA-seq. In total, 2191 genes were annotated for significant expression, which were mainly associated with metabolism and immunity. Pathway analysis showed that immune-related pathways of phagosome and cell adhesion molecules (CAMs) pathway were significantly down-regulated under low temperature. Moreover, ferroptosis, a significantly changed pathway involved in tissue damage and acute renal failure, is reported here for the first time. The levels of serum parameters associated with kidney damage such as urea and uric acid (UA) increased significantly under low temperature. The immunofluorescence staining of the kidney showed that cell apoptosis occurred at low temperature. The results of the present study indicate that exposure to low temperature can cause kidney disfunction and down-regulate the immune-related pathway in the kidney of tilapia. This study provides new insight into the mechanism of kidney damage in fish under low temperature.
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Affiliation(s)
- Tao Zhou
- International Research Center for Marine Biosciences, Ministry of Science and Technology, Shanghai Ocean University, Shanghai, China; Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai, China; National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, China
| | - Lang Gui
- International Research Center for Marine Biosciences, Ministry of Science and Technology, Shanghai Ocean University, Shanghai, China; Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai, China; National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, China
| | - Mingli Liu
- International Research Center for Marine Biosciences, Ministry of Science and Technology, Shanghai Ocean University, Shanghai, China; Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai, China; National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, China
| | - Wenhao Li
- International Research Center for Marine Biosciences, Ministry of Science and Technology, Shanghai Ocean University, Shanghai, China; Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai, China; National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, China
| | - Peng Hu
- International Research Center for Marine Biosciences, Ministry of Science and Technology, Shanghai Ocean University, Shanghai, China; Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai, China; National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, China
| | - Daniel F C Duarte
- Faculty of Sciences and Technology, University of Algarve, Faro, Portugal
| | - Hongbo Niu
- International Research Center for Marine Biosciences, Ministry of Science and Technology, Shanghai Ocean University, Shanghai, China; Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai, China; National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, China
| | - Liangbiao Chen
- International Research Center for Marine Biosciences, Ministry of Science and Technology, Shanghai Ocean University, Shanghai, China; Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai, China; National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, China.
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203
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Donhauser ZJ, Appadoo V, Kliman EJ, Jobs WB, Sheffield EC. Structural Changes in Tubulin Sheets Caused by Immobilization on Solid Supports. ACS OMEGA 2018; 3:18196-18202. [PMID: 30613819 PMCID: PMC6312633 DOI: 10.1021/acsomega.8b02475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 12/11/2018] [Indexed: 06/09/2023]
Abstract
In the presence of zinc, the protein tubulin assembles into two-dimensional sheets that are a useful model system for the study of both tubulin and microtubule structure. Tubulin sheets present an ideal protein structure for study with atomic force microscopy because they contain a two-dimensional crystalline protein lattice and retain many of the structural features of tubulin and microtubules. However, high-resolution imaging requires nonperturbative immobilization onto an appropriate imaging substrate. In this report, several substrates commonly used for scanning probe microscopy are evaluated for their ability to effectively immobilize tubulin sheets: mica, gold, highly ordered pyrolytic graphite, and carbon-coated electron microscopy grids. We hypothesize that the different intermolecular interactions presented by these substrates will affect the morphology of adsorbed tubulin sheets as well as the amount of other contaminating adsorbates. Tubulin sheets were successfully imaged on all of these substrates and structural characterization is reported. The most consistent results were obtained on carbon-coated electron microscopy grids, which preserved fine structural features of the sheets and had the least amount of contamination from the adsorption of unpolymerized tubulin. Images of tubulin sheets obtained with atomic force microscopy also compare favorably with published electron micrographs of sheets produced using similar procedures. This work demonstrates the importance of assessing substrate effects when studying two-dimensional protein crystals and identifies suitable substrates for immobilizing tubulin sheets.
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Affiliation(s)
| | | | - Elysa J. Kliman
- Vassar College, 124 Raymond Avenue, Poughkeepsie, New York 12604, United States
| | - William B. Jobs
- Vassar College, 124 Raymond Avenue, Poughkeepsie, New York 12604, United States
| | - Evan C. Sheffield
- Vassar College, 124 Raymond Avenue, Poughkeepsie, New York 12604, United States
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204
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Wang F, Yang W, Hu X. Discovery of High Affinity Receptors for Dityrosine through Inverse Virtual Screening and Docking and Molecular Dynamics. Int J Mol Sci 2018; 20:ijms20010115. [PMID: 30597963 PMCID: PMC6337580 DOI: 10.3390/ijms20010115] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2018] [Revised: 12/21/2018] [Accepted: 12/23/2018] [Indexed: 01/22/2023] Open
Abstract
Dityrosine is the product of oxidation that has been linked to a number of serious pathological conditions. Evidence indicates that high amounts of dityrosine exist in oxidized milk powders and some milk related foodstuffs, further reducing the nutritional value of oxidized proteins. Therefore, we hypothesize that some receptors related to special diseases would be targets for dityrosine. However, the mechanisms of the interaction of dityrosine with probable targets are still unknown. In the present work, an inverse virtual screening approach was performed to screen possible novel targets for dityrosine. Molecular docking studies were performed on a panel of targets extracted from the potential drug target database (PDTD) to optimize and validate the screening results. Firstly, two different conformations cis- and trans- were found for dityrosine during minimization. Moreover, Tubulin (αT) (−11.0 kcal/mol) was identified as a target for cis-dityrosine (CDT), targets including αT (−11.2 kcal/mol) and thyroid hormone receptor beta-1 (−10.7 kcal/mol) presented high binding affinities for trans-dityrosine (TDT). Furthermore, in order to provide binding complexes with higher precision, the three docked systems were further refined by performing thermo dynamic simulations. A series of techniques for searching for the most stable binding pose and the calculation of binding free energy are elaborately provided in this work. The major interactions between these targets and dityrosine were hydrophobic, electrostatic and hydrogen bonding. The application of inverse virtual screening method may facilitate the prediction of unknown targets for known ligands, and direct future experimental assays.
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Affiliation(s)
- Fangfang Wang
- School of Life Science, Linyi University, Linyi 276000, China.
| | - Wei Yang
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia.
- Arieh Warshel Institute of Computational Biology, the Chinese University of Hong Kong, 2001 Longxiang Road, Longgang District, Shenzhen 518000, China.
| | - Xiaojun Hu
- School of Life Science, Linyi University, Linyi 276000, China.
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205
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Majumdar S, Basu D, Ghosh Dastidar S. Conformational States of E7010 Is Complemented by Microclusters of Water Inside the α,β-Tubulin Core. J Chem Inf Model 2018; 59:2274-2286. [PMID: 30516382 DOI: 10.1021/acs.jcim.8b00538] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The α,β-tubulin is the building block of microtubules, which is associated with and dissociated from the microtubular architecture complying with the dynamic instability of the microtubules. This dynamic instability has a direct relation with the spindle formation by the microtubules and cell division kinetics. E7010 is one of the promising ligands of an α,β-tubulin protein that binds at the core of this protein and can diminish the protein's ability to fit to a growing microtubule, thus frustrating cell division. Although X-ray crystallography has reported a specific binding conformation of E7010 in PDB, molecular dynamics (MD) simulations have revealed two other conformational states of the ligand capable of binding to tubulin with stabilities close to that state reported in PDB. To rationalize this quasidegeneracy of ligand binding modes, MD simulations have further revealed that the understanding of the mechanism of E7010-tubulin binding remains incomplete unless the role of water molecules to bridge this interaction is taken into consideration, a very critical insight that was not visible from the PDB structure. Further, these water molecules differ from the standard examples of "bridging" waters which generally exist as isolated water molecules between the receptor and the ligand. In the present case, the water molecules sandwiched between ligand and protein, sequestered from the bulk solvent, integrate with each other by an H-bonds network forming a group, which appear as microclusters of water. The structural packing with the ligand binding pocket and the bridging interactions between protein and ligand take place through such clusters. The presence of this microcluster of water is not just cosmetic, instead they have a crucial impact on the ligand binding thermodynamics. Only with the explicit consideration of these water clusters in the binding energy calculations (MMGBSA) is the stability of the native mode of ligand binding reported in PDB rationalized. At the same time, two other binding modes are elucidated to be quasi-degenerate with the native state and that indicates the further possibility in gaining more entropic stabilization of the complex. The role of such "bridging" water clusters to enhance the protein-ligand interaction will be insightful for designing the next generation prospective compounds in the field of cancer therapeutics.
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Affiliation(s)
- Sarmistha Majumdar
- Division of Bioinformatics , Bose Institute , P-1/12 C.I.T. Scheme VII M , Kolkata 700054 , India
| | - Debadrita Basu
- Division of Bioinformatics , Bose Institute , P-1/12 C.I.T. Scheme VII M , Kolkata 700054 , India
| | - Shubhra Ghosh Dastidar
- Division of Bioinformatics , Bose Institute , P-1/12 C.I.T. Scheme VII M , Kolkata 700054 , India
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206
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Ganser C, Uchihashi T. Microtubule self-healing and defect creation investigated by in-line force measurements during high-speed atomic force microscopy imaging. NANOSCALE 2018; 11:125-135. [PMID: 30525150 DOI: 10.1039/c8nr07392a] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Microtubules are biopolymers composed of tubulin and play diverse roles in a wide variety of biological processes such as cell division, migration and intracellular transport in eukaryotic cells. To perform their functions, microtubules are mechanically stressed and, thereby, susceptible to structural defects. Local variations in mechanical properties caused by these defects modulate their biological functions, including binding and transportation of microtubule-associated proteins. Therefore, assessing the local mechanical properties of microtubules and analyzing their dynamic response to mechanical stimuli provide insight into fundamental processes. It is, however, not trivial to control defect formation, gather mechanical information at the same time, and subsequently image the result at a high temporal resolution at the molecular level with minimal delay. In this work, we describe the so-called in-line force curve mode based on high-speed atomic force microscopy. This method is directly applied to create defects in microtubules at the level of tubulin dimers and monitor the following dynamic processes around the defects. Furthermore, force curves obtained during defect formation provide quantitative mechanical information to estimate the bonding energy between tubulin dimers.
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Affiliation(s)
- Christian Ganser
- Department of Physics, Nagoya University, Chikusa-ku, Furo-cho, 464-8602 Nagoya, Aichi, Japan.
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207
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Manka SW, Moores CA. Microtubule structure by cryo-EM: snapshots of dynamic instability. Essays Biochem 2018; 62:737-751. [PMID: 30315096 PMCID: PMC6281474 DOI: 10.1042/ebc20180031] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 09/14/2018] [Accepted: 09/19/2018] [Indexed: 01/24/2023]
Abstract
The development of cryo-electron microscopy (cryo-EM) allowed microtubules to be captured in their solution-like state, enabling decades of insight into their dynamic mechanisms and interactions with binding partners. Cryo-EM micrographs provide 2D visualization of microtubules, and these 2D images can also be used to reconstruct the 3D structure of the polymer and any associated binding partners. In this way, the binding sites for numerous components of the microtubule cytoskeleton-including motor domains from many kinesin motors, and the microtubule-binding domains of dynein motors and an expanding collection of microtubule associated proteins-have been determined. The effects of various microtubule-binding drugs have also been studied. High-resolution cryo-EM structures have also been used to probe the molecular basis of microtubule dynamic instability, driven by the GTPase activity of β-tubulin. These studies have shown the conformational changes in lattice-confined tubulin dimers in response to steps in the tubulin GTPase cycle, most notably lattice compaction at the longitudinal inter-dimer interface. Although work is ongoing to define a complete structural model of dynamic instability, attention has focused on the role of gradual destabilization of lateral contacts between tubulin protofilaments, particularly at the microtubule seam. Furthermore, lower resolution cryo-electron tomography 3D structures are shedding light on the heterogeneity of microtubule ends and how their 3D organization contributes to dynamic instability. The snapshots of these polymers captured using cryo-EM will continue to provide critical insights into their dynamics, interactions with cellular components, and the way microtubules contribute to cellular functions in diverse physiological contexts.
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Affiliation(s)
- Szymon W Manka
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, London, U.K.
| | - Carolyn A Moores
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, London, U.K
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208
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Abtouche S, Issad-Elkebich M, Brahimi M, Assfeld X. Complexation of Ca2+ cation by the lateral chain of Paclitaxel (N-Benzoyl-ß-phenylisoserine): A theoretical study. COMPUT THEOR CHEM 2018. [DOI: 10.1016/j.comptc.2018.11.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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209
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Abstract
Cryo-electron microscopy, or simply cryo-EM, refers mainly to three very different yet closely related techniques: electron crystallography, single-particle cryo-EM, and electron cryotomography. In the past few years, single-particle cryo-EM in particular has triggered a revolution in structural biology and has become a newly dominant discipline. This Review examines the fascinating story of its start and evolution over the past 40-plus years, delves into how and why the recent technological advances have been so groundbreaking, and briefly considers where the technique may be headed in the future.
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Affiliation(s)
- Yifan Cheng
- Howard Hughes Medical Institute, Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, USA
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210
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Vicente-Blázquez A, González M, Álvarez R, Del Mazo S, Medarde M, Peláez R. Antitubulin sulfonamides: The successful combination of an established drug class and a multifaceted target. Med Res Rev 2018; 39:775-830. [PMID: 30362234 DOI: 10.1002/med.21541] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 09/02/2018] [Accepted: 09/06/2018] [Indexed: 12/13/2022]
Abstract
Tubulin, the microtubules and their dynamic behavior are amongst the most successful antitumor, antifungal, antiparasitic, and herbicidal drug targets. Sulfonamides are exemplary drugs with applications in the clinic, in veterinary and in the agrochemical industry. This review summarizes the actual state and recent progress of both fields looking from the double point of view of the target and its drugs, with special focus onto the structural aspects. The article starts with a brief description of tubulin structure and its dynamic assembly and disassembly into microtubules and other polymers. Posttranslational modifications and the many cellular means of regulating and modulating tubulin's biology are briefly presented in the tubulin code. Next, the structurally characterized drug binding sites, their occupying drugs and the effects they induce are described, emphasizing on the structural requirements for high potency, selectivity, and low toxicity. The second part starts with a summary of the favorable and highly tunable combination of physical-chemical and biological properties that render sulfonamides a prototypical example of privileged scaffolds with representatives in many therapeutic areas. A complete description of tubulin-binding sulfonamides is provided, covering the different species and drug sites. Some of the antimitotic sulfonamides have met with very successful applications and others less so, thus illustrating the advances, limitations, and future perspectives of the field. All of them combine in a mechanism of action and a clinical outcome that conform efficient drugs.
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Affiliation(s)
- Alba Vicente-Blázquez
- Laboratorio de Química Orgánica y Farmacéutica, Departamento de Ciencias Farmacéuticas, Universidad de Salamanca, Campus Miguel de Unamuno, Salamanca, Spain.,Facultad de Farmacia, Instituto de Investigación Biomédica de Salamanca (IBSAL), Universidad de Salamanca, Campus Miguel de Unamuno, Salamanca, Spain.,Facultad de Farmacia, Centro de Investigación de Enfermedades Tropicales de la Universidad de Salamanca (CIETUS), Universidad de Salamanca, Campus Miguel de Unamuno, Salamanca, Spain.,Laboratory of Cell Death and Cancer Therapy, Department of Molecular Biomedicine, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
| | - Myriam González
- Laboratorio de Química Orgánica y Farmacéutica, Departamento de Ciencias Farmacéuticas, Universidad de Salamanca, Campus Miguel de Unamuno, Salamanca, Spain.,Facultad de Farmacia, Instituto de Investigación Biomédica de Salamanca (IBSAL), Universidad de Salamanca, Campus Miguel de Unamuno, Salamanca, Spain.,Facultad de Farmacia, Centro de Investigación de Enfermedades Tropicales de la Universidad de Salamanca (CIETUS), Universidad de Salamanca, Campus Miguel de Unamuno, Salamanca, Spain
| | - Raquel Álvarez
- Laboratorio de Química Orgánica y Farmacéutica, Departamento de Ciencias Farmacéuticas, Universidad de Salamanca, Campus Miguel de Unamuno, Salamanca, Spain.,Facultad de Farmacia, Instituto de Investigación Biomédica de Salamanca (IBSAL), Universidad de Salamanca, Campus Miguel de Unamuno, Salamanca, Spain.,Facultad de Farmacia, Centro de Investigación de Enfermedades Tropicales de la Universidad de Salamanca (CIETUS), Universidad de Salamanca, Campus Miguel de Unamuno, Salamanca, Spain
| | - Sara Del Mazo
- Laboratorio de Química Orgánica y Farmacéutica, Departamento de Ciencias Farmacéuticas, Universidad de Salamanca, Campus Miguel de Unamuno, Salamanca, Spain.,Facultad de Farmacia, Instituto de Investigación Biomédica de Salamanca (IBSAL), Universidad de Salamanca, Campus Miguel de Unamuno, Salamanca, Spain.,Facultad de Farmacia, Centro de Investigación de Enfermedades Tropicales de la Universidad de Salamanca (CIETUS), Universidad de Salamanca, Campus Miguel de Unamuno, Salamanca, Spain
| | - Manuel Medarde
- Laboratorio de Química Orgánica y Farmacéutica, Departamento de Ciencias Farmacéuticas, Universidad de Salamanca, Campus Miguel de Unamuno, Salamanca, Spain.,Facultad de Farmacia, Instituto de Investigación Biomédica de Salamanca (IBSAL), Universidad de Salamanca, Campus Miguel de Unamuno, Salamanca, Spain.,Facultad de Farmacia, Centro de Investigación de Enfermedades Tropicales de la Universidad de Salamanca (CIETUS), Universidad de Salamanca, Campus Miguel de Unamuno, Salamanca, Spain
| | - Rafael Peláez
- Laboratorio de Química Orgánica y Farmacéutica, Departamento de Ciencias Farmacéuticas, Universidad de Salamanca, Campus Miguel de Unamuno, Salamanca, Spain.,Facultad de Farmacia, Instituto de Investigación Biomédica de Salamanca (IBSAL), Universidad de Salamanca, Campus Miguel de Unamuno, Salamanca, Spain.,Facultad de Farmacia, Centro de Investigación de Enfermedades Tropicales de la Universidad de Salamanca (CIETUS), Universidad de Salamanca, Campus Miguel de Unamuno, Salamanca, Spain
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211
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Associations of canopy leaf traits with SNP markers in durum wheat (Triticum turgidum L. durum (Desf.)). PLoS One 2018; 13:e0206226. [PMID: 30352102 PMCID: PMC6198983 DOI: 10.1371/journal.pone.0206226] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 10/09/2018] [Indexed: 11/23/2022] Open
Abstract
The canopy leaves including the top three, i.e., the flag, the 2nd and 3rd from the top, are important for photosynthesis and grain yield of wheat. Molecular markers associated with traits of these leaves should be helpful for the high-yielding breeding. In this study, 1366 single nucleotide polymorphisms (SNP) markers covering the whole genome of durum wheat were used to genotype 150 cultivars collected from 46 countries and regions in the world. Leaf length, leaf width and chlorophyll content of the top three leaves were measured, respectively, in three consecutive years. Association analyses were performed on the leaf traits and SNP markers. A total of 120 SNP marker associations were detected on 13 of the 14 chromosomes. Among these markers, 83 were associated with the canopy leaf traits, 10 with 1000-grain weight, and 29 with kernel number per spike. This study is helpful for better understanding the potential and genetic basis of functional leaves, and facilitates pyramiding of the favorable alleles using marker assisted selection for ideal plant-type and high photosynthesis efficiency in durum wheat breeding.
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212
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Adnan A, Qidwai S, Bagchi A. On the atomistic-based continuum viscoelastic constitutive relations for axonal microtubules. J Mech Behav Biomed Mater 2018; 86:375-389. [DOI: 10.1016/j.jmbbm.2018.06.031] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Revised: 01/04/2018] [Accepted: 06/21/2018] [Indexed: 11/25/2022]
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213
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Chagas CM, Moss S, Alisaraie L. Drug metabolites and their effects on the development of adverse reactions: Revisiting Lipinski’s Rule of Five. Int J Pharm 2018; 549:133-149. [DOI: 10.1016/j.ijpharm.2018.07.046] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Revised: 07/19/2018] [Accepted: 07/20/2018] [Indexed: 12/13/2022]
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214
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Ti SC, Alushin GM, Kapoor TM. Human β-Tubulin Isotypes Can Regulate Microtubule Protofilament Number and Stability. Dev Cell 2018; 47:175-190.e5. [PMID: 30245156 DOI: 10.1016/j.devcel.2018.08.014] [Citation(s) in RCA: 83] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 06/28/2018] [Accepted: 08/20/2018] [Indexed: 10/28/2022]
Abstract
Cell biological studies have shown that protofilament number, a fundamental feature of microtubules, can correlate with the expression of different tubulin isotypes. However, it is not known if tubulin isotypes directly control this basic microtubule property. Here, we report high-resolution cryo-EM reconstructions (3.5-3.65 Å) of purified human α1B/β3 and α1B/β2B microtubules and find that the β-tubulin isotype can determine protofilament number. Comparisons of atomic models of 13- and 14-protofilament microtubules reveal how tubulin subunit plasticity, manifested in "accordion-like" distributed structural changes, can accommodate distinct lattice organizations. Furthermore, compared to α1B/β3 microtubules, α1B/β2B filaments are more stable to passive disassembly and against depolymerization by MCAK or chTOG, microtubule-associated proteins with distinct mechanisms of action. Mixing tubulin isotypes in different proportions results in microtubules with protofilament numbers and stabilities intermediate to those of isotypically pure filaments. Together, our findings indicate that microtubule protofilament number and stability can be controlled through β-tubulin isotype composition.
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Affiliation(s)
- Shih-Chieh Ti
- Laboratory of Chemistry and Cell Biology, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - Gregory M Alushin
- Laboratory of Structural Biophysics and Mechanobiology, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA.
| | - Tarun M Kapoor
- Laboratory of Chemistry and Cell Biology, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA.
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215
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Timmons JJ, Preto J, Tuszynski JA, Wong ET. Tubulin's response to external electric fields by molecular dynamics simulations. PLoS One 2018; 13:e0202141. [PMID: 30231050 PMCID: PMC6145594 DOI: 10.1371/journal.pone.0202141] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Accepted: 07/27/2018] [Indexed: 02/03/2023] Open
Abstract
Tubulin heterodimers are the building blocks of microtubules and disruption of their dynamics is exploited in the treatment of cancer. Electric fields at certain frequencies and magnitudes are believed to do the same. Here, the tubulin dimer’s response to external electric fields was determined by atomistic simulation. External fields from 50 to 750 kV/cm, applied for 10 ns, caused significant conformational rearrangements that were dependent upon the field’s directionality. Charged and flexible regions, including the α:H1-B2 loop, β:M-loop, and C-termini, were susceptible. Closer inspection of the α:H1-B2 loop in lower strength fields revealed that these effects were consistent and proportional to field strength, and the findings indicate that external electric fields modulate the stability of microtubules through conformational changes to key loops involved in lateral contacts. We also find evidence that tubulin’s curvature and elongation are affected, and external electric fields may bias tubulin towards depolymerization.
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Affiliation(s)
- Joshua J. Timmons
- Brain Tumor Center & Neuro-Oncology Unit, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Jordane Preto
- Department of Physics, University of Alberta, Edmonton, Canada
| | - Jack A. Tuszynski
- Department of Physics, University of Alberta, Edmonton, Canada
- Department of Oncology, University of Alberta, Edmonton, Canada
- Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Corso Duca degli Abruzzi, Torino, Italy
| | - Eric T. Wong
- Brain Tumor Center & Neuro-Oncology Unit, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail:
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216
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Martinho M, Allegro D, Huvent I, Chabaud C, Etienne E, Kovacic H, Guigliarelli B, Peyrot V, Landrieu I, Belle V, Barbier P. Two Tau binding sites on tubulin revealed by thiol-disulfide exchanges. Sci Rep 2018; 8:13846. [PMID: 30218010 PMCID: PMC6138654 DOI: 10.1038/s41598-018-32096-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Accepted: 08/14/2018] [Indexed: 01/25/2023] Open
Abstract
Tau is a Microtubule-associated protein that induces and stabilizes the formation of the Microtubule cytoskeleton and plays an important role in neurodegenerative diseases. The Microtubules binding region of Tau has been determined for a long time but where and how Tau binds to its partner still remain a topic of debate. We used Site Directed Spin Labeling combined with EPR spectroscopy to monitor Tau upon binding to either Taxol-stabilized MTs or to αβ-tubulin when Tau is directly used as an inducer of MTs formation. Using maleimide-functionalized labels grafted on the two natural cysteine residues of Tau, we found in both cases that Tau remains highly flexible in these regions confirming the fuzziness of Tau:MTs complexes. More interestingly, using labels linked by a disulfide bridge, we evidenced for the first time thiol disulfide exchanges between αβ-tubulin or MTs and Tau. Additionally, Tau fragments having the two natural cysteines or variants containing only one of them were used to determine the role of each cysteine individually. The difference observed in the label release kinetics between preformed MTs or Tau-induced MTs, associated to a comparison of structural data, led us to propose two putative binding sites of Tau on αβ-tubulin.
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Affiliation(s)
- Marlène Martinho
- Aix-Marseille Univ, CNRS, UMR 7281 BIP, Bioénergétique et Ingénierie des Protéines, Marseille, France
| | - Diane Allegro
- Aix-Marseille Univ, CNRS, UMR 7051, INP, Institut de Neurophysiopathologie, Marseille, France
| | | | - Charlotte Chabaud
- Aix-Marseille Univ, CNRS, UMR 7281 BIP, Bioénergétique et Ingénierie des Protéines, Marseille, France.,Aix-Marseille Univ, CNRS, UMR 7051, INP, Institut de Neurophysiopathologie, Marseille, France
| | - Emilien Etienne
- Aix-Marseille Univ, CNRS, UMR 7281 BIP, Bioénergétique et Ingénierie des Protéines, Marseille, France
| | - Hervé Kovacic
- Aix-Marseille Univ, CNRS, UMR 7051, INP, Institut de Neurophysiopathologie, Marseille, France
| | - Bruno Guigliarelli
- Aix-Marseille Univ, CNRS, UMR 7281 BIP, Bioénergétique et Ingénierie des Protéines, Marseille, France
| | - Vincent Peyrot
- Aix-Marseille Univ, CNRS, UMR 7051, INP, Institut de Neurophysiopathologie, Marseille, France
| | | | - Valérie Belle
- Aix-Marseille Univ, CNRS, UMR 7281 BIP, Bioénergétique et Ingénierie des Protéines, Marseille, France.
| | - Pascale Barbier
- Aix-Marseille Univ, CNRS, UMR 7051, INP, Institut de Neurophysiopathologie, Marseille, France.
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217
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Vulinovic F, Krajka V, Hausrat TJ, Seibler P, Alvarez-Fischer D, Madoev H, Park JS, Kumar KR, Sue CM, Lohmann K, Kneussel M, Klein C, Rakovic A. Motor protein binding and mitochondrial transport are altered by pathogenic TUBB4A variants. Hum Mutat 2018; 39:1901-1915. [PMID: 30079973 DOI: 10.1002/humu.23602] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Revised: 07/05/2018] [Accepted: 07/29/2018] [Indexed: 12/21/2022]
Abstract
Mutations in TUBB4A have been identified to cause a wide phenotypic spectrum of diseases ranging from hereditary generalized dystonia with whispering dysphonia (DYT-TUBB4A) and hereditary spastic paraplegia (HSP) to leukodystrophy hypomyelination with atrophy of the basal ganglia and cerebellum (H-ABC). TUBB4A encodes the brain-specific β-tubulin isotype, β-tubulin 4A. To elucidate the pathogenic mechanisms conferred by TUBB4A mutations leading to the different phenotypes, we functionally characterized three pathogenic TUBB4A variants (c.4C>G,p.R2G; c.745G>A,p.D249N; c.811G>A, p.A271T) as representatives of the mutational and disease spectrum) in human neuroblastoma cells and human induced pluripotent stem cell (iPSC)-derived neurons. We showed that mRNA stability was not affected by any of the TUBB4A variants. Although two mutations (p.R2G and p.D249N) are located at the α/β-tubulin interdimer interface, we confirmed incorporation of all TUBB4A mutants into the microtubule network. However, we showed that the mutations p.D249N and p.A271T interfered with motor protein binding to microtubules and impaired neurite outgrowth and microtubule dynamics. Finally, TUBB4A mutations, as well as heterozygous knockout of TUBB4A, disrupted mitochondrial transport in iPSC-derived neurons. Taken together, our findings suggest that functional impairment of microtubule-associated transport is a shared pathogenic mechanism by which the TUBB4A mutations studied here cause a spectrum of diseases.
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Affiliation(s)
- Franca Vulinovic
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany
| | - Victor Krajka
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany
| | - Torben J Hausrat
- Institute of Molecular Neurogenetics, Center for Molecular Neurobiology, ZMNH, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Philip Seibler
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany
| | | | - Harutyun Madoev
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany
| | - Jin-Sung Park
- Department of Neurogenetics, Kolling Institute, Royal North Shore Hospital and the University of Sydney, St. Leonards, New South Wales, Australia
| | - Kishore R Kumar
- Department of Neurogenetics, Kolling Institute, Royal North Shore Hospital and the University of Sydney, St. Leonards, New South Wales, Australia
- Kinghorn Centre for Clinical Genomics, Garvan Institute of Medical Research, Darlinghurst, Australia
| | - Carolyn M Sue
- Department of Neurogenetics, Kolling Institute, Royal North Shore Hospital and the University of Sydney, St. Leonards, New South Wales, Australia
| | - Katja Lohmann
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany
| | - Matthias Kneussel
- Institute of Molecular Neurogenetics, Center for Molecular Neurobiology, ZMNH, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Christine Klein
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany
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218
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Tajielyato N, Li L, Peng Y, Alper J, Alexov E. E-hooks provide guidance and a soft landing for the microtubule binding domain of dynein. Sci Rep 2018; 8:13266. [PMID: 30185874 PMCID: PMC6125590 DOI: 10.1038/s41598-018-31480-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Accepted: 08/15/2018] [Indexed: 01/14/2023] Open
Abstract
Macromolecular binding is a complex process that involves sensing and approaching the binding partner, adopting the proper orientation, and performing the physical binding. We computationally investigated the role of E-hooks, which are intrinsically disordered regions (IDRs) at the C-terminus of tubulin, on dynein microtubule binding domain (MTBD) binding to the microtubule as a function of the distance between the MTBD and its binding site on the microtubule. Our results demonstrated that the contacts between E-hooks and the MTBD are dynamical; multiple negatively charted patches of amino acids on the E-hooks grab and release the same positively charged patches on the MTBD as it approaches the microtubule. Even when the distance between the MTBD and the microtubule was greater than the E-hook length, the E-hooks sensed and guided MTBD via long-range electrostatic interactions in our simulations. Moreover, we found that E-hooks exerted electrostatic forces on the MTBD that were distance dependent; the force pulls the MTBD toward the microtubule at long distances but opposes binding at short distances. This mechanism provides a "soft-landing" for the MTBD as it binds to the microtubule. Finally, our analysis of the conformational states of E-hooks in presence and absence of the MTBD indicates that the binding process is a mixture of the induced-fit and lock-and-key macromolecular binding hypotheses. Overall, this novel binding mechanism is termed "guided-soft-binding" and could have broad-reaching impacts on the understanding of how IDRs dock to structured proteins.
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Affiliation(s)
- Nayere Tajielyato
- Department of Physics and Astronomy, Clemson University, Clemson, SC, 29634, USA
| | - Lin Li
- Department of Physics and Astronomy, Clemson University, Clemson, SC, 29634, USA
- Department of Physics, University of Texas at El Paso, El Paso, TX, 79912, USA
| | - Yunhui Peng
- Department of Physics and Astronomy, Clemson University, Clemson, SC, 29634, USA
| | - Joshua Alper
- Department of Physics and Astronomy, Clemson University, Clemson, SC, 29634, USA.
| | - Emil Alexov
- Department of Physics and Astronomy, Clemson University, Clemson, SC, 29634, USA.
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219
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Polarized Organization of the Cytoskeleton: Regulation by Cell Polarity Proteins. J Mol Biol 2018; 430:3565-3584. [DOI: 10.1016/j.jmb.2018.06.028] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 06/09/2018] [Accepted: 06/13/2018] [Indexed: 01/02/2023]
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220
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Nakahata Y, Yasuda R. Plasticity of Spine Structure: Local Signaling, Translation and Cytoskeletal Reorganization. Front Synaptic Neurosci 2018; 10:29. [PMID: 30210329 PMCID: PMC6123351 DOI: 10.3389/fnsyn.2018.00029] [Citation(s) in RCA: 133] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 08/07/2018] [Indexed: 12/31/2022] Open
Abstract
Dendritic spines are small protrusive structures on dendritic surfaces, and function as postsynaptic compartments for excitatory synapses. Plasticity of spine structure is associated with many forms of long-term neuronal plasticity, learning and memory. Inside these small dendritic compartments, biochemical states and protein-protein interactions are dynamically modulated by synaptic activity, leading to the regulation of protein synthesis and reorganization of cytoskeletal architecture. This in turn causes plasticity of structure and function of the spine. Technical advances in monitoring molecular behaviors in single dendritic spines have revealed that each signaling pathway is differently regulated across multiple spatiotemporal domains. The spatial pattern of signaling activity expands from a single spine to the nearby dendritic area, dendritic branch and the nucleus, regulating different cellular events at each spatial scale. Temporally, biochemical events are typically triggered by short Ca2+ pulses (~10–100 ms). However, these signals can then trigger activation of downstream protein cascades that can last from milliseconds to hours. Recent imaging studies provide many insights into the biochemical processes governing signaling events of molecular assemblies at different spatial localizations. Here, we highlight recent findings of signaling dynamics during synaptic plasticity and discuss their roles in long-term structural plasticity of dendritic spines.
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Affiliation(s)
- Yoshihisa Nakahata
- Neuronal Signal Transduction, Max Planck Florida Institute for Neuroscience (MPFI), Jupiter, FL, United States
| | - Ryohei Yasuda
- Neuronal Signal Transduction, Max Planck Florida Institute for Neuroscience (MPFI), Jupiter, FL, United States
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221
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Mphahlele MJ, Maluleka MM, Parbhoo N, Malindisa ST. Synthesis, Evaluation for Cytotoxicity and Molecular Docking Studies of Benzo[ c]furan-Chalcones for Potential to Inhibit Tubulin Polymerization and/or EGFR-Tyrosine Kinase Phosphorylation. Int J Mol Sci 2018; 19:E2552. [PMID: 30154363 PMCID: PMC6164331 DOI: 10.3390/ijms19092552] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 08/13/2018] [Accepted: 08/17/2018] [Indexed: 12/13/2022] Open
Abstract
A series of 2-arylbenzo[c]furan-chalcone hybrids 3a⁻y have been synthesized and evaluated for antiproliferative effects against the human breast cancer (MCF-7) cell line and for its potential to induce apoptosis and also to inhibit tubulin polymerization and/or epidermal growth factor receptor-tyrosine kinase (EGFR-TK) phosphorylation. Most of these compounds exhibited moderate to significant antigrowth effects in vitro against the MCF-7 cell line when compared to the reference standard actinomycin D. The capabilities of the most cytotoxic benzofuran-chalcone hybrids 3b and 3i, to induce apoptosis, have been evaluated by Annexin V-Cy3 SYTOX staining and caspase-3 activation. The experimental and molecular docking results suggest that the title compounds have the potential to exhibit inhibitory effects against tubulin polymerization and epidermal growth factor receptor tyrosine kinase (EGFR-TK) phosphorylation. The modeled structures of representative compounds displayed hydrophobic interactions as well as hydrogen and/or halogen bonding with the protein residues. These interactions are probably responsible for the observed increased binding affinity for the two receptors and their significant antigrowth effect against the MCF-7 cell line.
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Affiliation(s)
- Malose J Mphahlele
- Department of Chemistry, College of Science, Engineering and Technology, University of South Africa, Private Bag X06, Florida 1710, South Africa.
| | - Marole M Maluleka
- Department of Chemistry, College of Science, Engineering and Technology, University of South Africa, Private Bag X06, Florida 1710, South Africa.
| | - Nishal Parbhoo
- Department of Life & Consumer Sciences, College of Agriculture and Environmental Sciences, University of South Africa, Private Bag X06, Florida 1710, South Africa.
| | - Sibusiso T Malindisa
- Department of Life & Consumer Sciences, College of Agriculture and Environmental Sciences, University of South Africa, Private Bag X06, Florida 1710, South Africa.
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222
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Barvitenko N, Lawen A, Aslam M, Pantaleo A, Saldanha C, Skverchinskaya E, Regolini M, Tuszynski JA. Integration of intracellular signaling: Biological analogues of wires, processors and memories organized by a centrosome 3D reference system. Biosystems 2018; 173:191-206. [PMID: 30142359 DOI: 10.1016/j.biosystems.2018.08.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 08/03/2018] [Accepted: 08/20/2018] [Indexed: 02/07/2023]
Abstract
BACKGROUND Myriads of signaling pathways in a single cell function to achieve the highest spatio-temporal integration. Data are accumulating on the role of electromechanical soliton-like waves in signal transduction processes. Theoretical studies strongly suggest feasibility of both classical and quantum computing involving microtubules. AIM A theoretical study of the role of the complex composed of the plasma membrane and the microtubule-based cytoskeleton as a system that transmits, stores and processes information. METHODS Theoretical analysis presented here refers to (i) the Penrose-Hameroff theory of consciousness (Orchestrated Objective Reduction; Orch OR), (ii) the description of the centrosome as a reference system for construction of the 3D map of the cell proposed by Regolini, (iii) the Heimburg-Jackson model of the nerve pulse propagation along axons' lipid bilayer as soliton-like electro-mechanical waves. RESULTS AND CONCLUSION The ideas presented in this paper provide a qualitative model for the decision-making processes in a living cell undergoing a differentiation process. OUTLOOK This paper paves the way for the real-time live-cell observation of information processing by microtubule-based cytoskeleton and cell fate decision making.
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Affiliation(s)
| | - Alfons Lawen
- Monash University, School of Biomedical Sciences, Department of Biochemistry and Molecular Biology, VIC, 3800, Australia
| | - Muhammad Aslam
- Medical Clininc I, Cardiology/Angiology, University Hospital, Justus-Liebig-University, Giessen, Germany
| | - Antonella Pantaleo
- Department of Biomedical Sciences, University of Sassari, Sassari, Italy
| | - Carlota Saldanha
- Instituto de Medicina Molecular, Instituto de Bioquimica, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| | | | - Marco Regolini
- Department of Bioengineering and Mathematical Modeling, AudioLogic, Milan, Italy
| | - Jack A Tuszynski
- Department of Oncology, University of Alberta, Edmonton, Alberta, Canada; Department of Physics, University of Alberta, Edmonton, Alberta, Canada; Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Corso Duca degli Abruzzi 24, IT-10128, Torino, Italy.
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223
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Henderson R. Von der Elektronenkristallographie zur Einzelpartikel-KryoEM (Nobel-Aufsatz). Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201802731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Richard Henderson
- MRC Laboratory of Molecular Biology; Francis Crick Avenue Cambridge CB2 0QH Großbritannien
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224
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Maier LJ, Kallenberger SM, Jechow K, Waschow M, Eils R, Conrad C. Unraveling mitotic protein networks by 3D multiplexed epitope drug screening. Mol Syst Biol 2018; 14:e8238. [PMID: 30104419 PMCID: PMC6088390 DOI: 10.15252/msb.20188238] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 07/17/2018] [Accepted: 07/19/2018] [Indexed: 12/13/2022] Open
Abstract
Three-dimensional protein localization intricately determines the functional coordination of cellular processes. The complex spatial context of protein landscape has been assessed by multiplexed immunofluorescent staining or mass spectrometry, applied to 2D cell culture with limited physiological relevance or tissue sections. Here, we present 3D SPECS, an automated technology for 3D Spatial characterization of Protein Expression Changes by microscopic Screening. This workflow comprises iterative antibody staining, high-content 3D imaging, and machine learning for detection of mitoses. This is followed by mapping of spatial protein localization into a spherical, cellular coordinate system, a basis for model-based prediction of spatially resolved affinities of proteins. As a proof-of-concept, we mapped twelve epitopes in 3D-cultured spheroids and investigated the network effects of twelve mitotic cancer drugs. Our approach reveals novel insights into spindle fragility and chromatin stress, and predicts unknown interactions between proteins in specific mitotic pathways. 3D SPECS's ability to map potential drug targets by multiplexed immunofluorescence in 3D cell culture combined with our automated high-content assay will inspire future functional protein expression and drug assays.
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Affiliation(s)
- Lorenz J Maier
- Center for Quantitative Analysis of Molecular and Cellular Biosystems (BioQuant), Heidelberg University, Heidelberg, Germany
- Division of Theoretical Bioinformatics, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Department for Bioinformatics and Functional Genomics, Institute for Pharmacy and Molecular Biotechnology (IPMB), Heidelberg University, Heidelberg, Germany
| | - Stefan M Kallenberger
- Center for Quantitative Analysis of Molecular and Cellular Biosystems (BioQuant), Heidelberg University, Heidelberg, Germany
- Division of Theoretical Bioinformatics, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Department for Bioinformatics and Functional Genomics, Institute for Pharmacy and Molecular Biotechnology (IPMB), Heidelberg University, Heidelberg, Germany
| | - Katharina Jechow
- Division of Theoretical Bioinformatics, German Cancer Research Center (DKFZ), Heidelberg, Germany
- BIH Center for Digital Health, Charité Universitätsmedizin Berlin and Berlin Institute of Health, Berlin, Germany
| | - Marcel Waschow
- Division of Theoretical Bioinformatics, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Roland Eils
- Center for Quantitative Analysis of Molecular and Cellular Biosystems (BioQuant), Heidelberg University, Heidelberg, Germany
- Division of Theoretical Bioinformatics, German Cancer Research Center (DKFZ), Heidelberg, Germany
- BIH Center for Digital Health, Charité Universitätsmedizin Berlin and Berlin Institute of Health, Berlin, Germany
| | - Christian Conrad
- Center for Quantitative Analysis of Molecular and Cellular Biosystems (BioQuant), Heidelberg University, Heidelberg, Germany
- Division of Theoretical Bioinformatics, German Cancer Research Center (DKFZ), Heidelberg, Germany
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225
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Varidaki A, Hong Y, Coffey ET. Repositioning Microtubule Stabilizing Drugs for Brain Disorders. Front Cell Neurosci 2018; 12:226. [PMID: 30135644 PMCID: PMC6092511 DOI: 10.3389/fncel.2018.00226] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 07/12/2018] [Indexed: 12/13/2022] Open
Abstract
Microtubule stabilizing agents are among the most clinically useful chemotherapeutic drugs. Mostly, they act to stabilize microtubules and inhibit cell division. While not without side effects, new generations of these compounds display improved pharmacokinetic properties and brain penetrance. Neurological disorders are intrinsically associated with microtubule defects, and efforts to reposition microtubule-targeting chemotherapeutic agents for treatment of neurodegenerative and psychiatric illnesses are underway. Here we catalog microtubule regulators that are associated with Alzheimer's and Parkinson's disease, amyotrophic lateral sclerosis, schizophrenia and mood disorders. We outline the classes of microtubule stabilizing agents used for cancer treatment, their brain penetrance properties and neuropathy side effects, and describe efforts to apply these agents for treatment of brain disorders. Finally, we summarize the current state of clinical trials for microtubule stabilizing agents under evaluation for central nervous system disorders.
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Affiliation(s)
- Artemis Varidaki
- Turku Centre for Biotechnology, Åbo Akademi University and University of Turku, Biocity, Tykistokatu, Turku, Finland
| | - Ye Hong
- Turku Centre for Biotechnology, Åbo Akademi University and University of Turku, Biocity, Tykistokatu, Turku, Finland
| | - Eleanor T Coffey
- Turku Centre for Biotechnology, Åbo Akademi University and University of Turku, Biocity, Tykistokatu, Turku, Finland
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226
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Sahakyan HK, Arakelov GG, Nazaryan KB. In silico Search for Tubulin Polymerization Inhibitors. Mol Biol 2018. [DOI: 10.1134/s0026893318040179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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227
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Rank M, Frey E. Crowding and Pausing Strongly Affect Dynamics of Kinesin-1 Motors along Microtubules. Biophys J 2018; 115:1068-1081. [PMID: 30146266 PMCID: PMC6139881 DOI: 10.1016/j.bpj.2018.07.017] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 06/27/2018] [Accepted: 07/16/2018] [Indexed: 12/21/2022] Open
Abstract
Molecular motors of the kinesin-1 family move in a directed and processive fashion along microtubules. It is generally accepted that steric hindrance of motors leads to crowding effects; however, little is known about the specific interactions involved. We employ an agent-based lattice gas model to study the impact of interactions that enhance the detachment of motors from crowded filaments on their collective dynamics. The predictions of our model quantitatively agree with the experimentally observed concentration dependence of key motor characteristics including their run length, dwell time, velocity, and landing rate. From the anomalous stepping statistics of individual motors that exhibit relatively long pauses, we infer that kinesin-1 motors sometimes lapse into an inactive state. Hereby, the formation of traffic jams amplifies the impact of single inactive motors and leads to a crowding dependence of the frequencies and durations of the resulting periods of no or slow motion. We interpret these findings and conclude that kinesin-1 spends a significant fraction of its stepping cycle in a weakly bound state in which only one of its heads is bound to the microtubule.
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Affiliation(s)
- Matthias Rank
- Arnold Sommerfeld Center for Theoretical Physics and Center for NanoScience, Ludwig-Maximilians-Universität München, München, Germany
| | - Erwin Frey
- Arnold Sommerfeld Center for Theoretical Physics and Center for NanoScience, Ludwig-Maximilians-Universität München, München, Germany.
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228
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Lacroix B, Letort G, Pitayu L, Sallé J, Stefanutti M, Maton G, Ladouceur AM, Canman JC, Maddox PS, Maddox AS, Minc N, Nédélec F, Dumont J. Microtubule Dynamics Scale with Cell Size to Set Spindle Length and Assembly Timing. Dev Cell 2018; 45:496-511.e6. [PMID: 29787710 DOI: 10.1016/j.devcel.2018.04.022] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Revised: 03/22/2018] [Accepted: 04/24/2018] [Indexed: 12/22/2022]
Abstract
Successive cell divisions during embryonic cleavage create increasingly smaller cells, so intracellular structures must adapt accordingly. Mitotic spindle size correlates with cell size, but the mechanisms for this scaling remain unclear. Using live cell imaging, we analyzed spindle scaling during embryo cleavage in the nematode Caenorhabditis elegans and sea urchin Paracentrotus lividus. We reveal a common scaling mechanism, where the growth rate of spindle microtubules scales with cell volume, which explains spindle shortening. Spindle assembly timing is, however, constant throughout successive divisions. Analyses in silico suggest that controlling the microtubule growth rate is sufficient to scale spindle length and maintain a constant assembly timing. We tested our in silico predictions to demonstrate that modulating cell volume or microtubule growth rate in vivo induces a proportional spindle size change. Our results suggest that scalability of the microtubule growth rate when cell size varies adapts spindle length to cell volume.
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Affiliation(s)
- Benjamin Lacroix
- Institut Jacques Monod, CNRS, UMR 7592, University Paris Diderot, Sorbonne Paris Cité, 75205 Paris, France.
| | - Gaëlle Letort
- Institut Curie, Mines Paris Tech, Inserm, U900, PSL Research University, 75005 Paris, France
| | - Laras Pitayu
- Institut Jacques Monod, CNRS, UMR 7592, University Paris Diderot, Sorbonne Paris Cité, 75205 Paris, France
| | - Jérémy Sallé
- Institut Jacques Monod, CNRS, UMR 7592, University Paris Diderot, Sorbonne Paris Cité, 75205 Paris, France
| | - Marine Stefanutti
- Institut Jacques Monod, CNRS, UMR 7592, University Paris Diderot, Sorbonne Paris Cité, 75205 Paris, France
| | - Gilliane Maton
- Institut Jacques Monod, CNRS, UMR 7592, University Paris Diderot, Sorbonne Paris Cité, 75205 Paris, France
| | | | - Julie C Canman
- Columbia University Medical Center, Department of Pathology and Cell Biology, New York, NY 10032, USA
| | - Paul S Maddox
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Amy S Maddox
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Nicolas Minc
- Institut Jacques Monod, CNRS, UMR 7592, University Paris Diderot, Sorbonne Paris Cité, 75205 Paris, France
| | - François Nédélec
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany.
| | - Julien Dumont
- Institut Jacques Monod, CNRS, UMR 7592, University Paris Diderot, Sorbonne Paris Cité, 75205 Paris, France.
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229
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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 PMCID: PMC6052224 DOI: 10.1074/jbc.ra117.001569] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [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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230
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Henderson R. From Electron Crystallography to Single Particle CryoEM (Nobel Lecture). Angew Chem Int Ed Engl 2018; 57:10804-10825. [PMID: 29984560 DOI: 10.1002/anie.201802731] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Indexed: 01/08/2023]
Abstract
Pictures are a key to knowledge: The development of electron microscopy from its beginnings to modern single particle cryo-EM is described by R. Henderson in his Nobel lecture. Shown is the first projection structure at 7 Å resolution of the purple membrane from October 1974.
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Affiliation(s)
- Richard Henderson
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
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231
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The role of tubulin-tubulin lattice contacts in the mechanism of microtubule dynamic instability. Nat Struct Mol Biol 2018; 25:607-615. [PMID: 29967541 PMCID: PMC6201834 DOI: 10.1038/s41594-018-0087-8] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Accepted: 06/01/2018] [Indexed: 11/08/2022]
Abstract
Microtubules form from longitudinally and laterally assembling tubulin α-β dimers. The assembly induces strain in tubulin, resulting in cycles of microtubule catastrophe and regrowth. This 'dynamic instability' is governed by GTP hydrolysis that renders the microtubule lattice unstable, but it is unclear how. We used a human microtubule nucleating and stabilizing neuronal protein, doublecortin, and high-resolution cryo-EM to capture tubulin's elusive hydrolysis intermediate GDP•Pi state, alongside the prehydrolysis analog GMPCPP state and the posthydrolysis GDP state with and without an anticancer drug, Taxol. GTP hydrolysis to GDP•Pi followed by Pi release constitutes two distinct structural transitions, causing unevenly distributed compressions of tubulin dimers, thereby tightening longitudinal and loosening lateral interdimer contacts. We conclude that microtubule catastrophe is triggered because the lateral contacts can no longer counteract the strain energy stored in the lattice, while reinforcement of the longitudinal contacts may support generation of force.
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232
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233
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Abstract
We report three high-resolution structures of microtubules in different nucleotide states—GMPCPP, GDP, and GTPγS—in the absence of any binding proteins, allowing us to separate the effects of nucleotide- and microtubule (MT)-associated protein (MAPs) binding on MT structure. End-binding (EB) proteins can bind and induce partial lattice compaction of a preformed GMPCPP-bound MT, a lattice type that is far from EBs’ ideal binding platform. We propose a model in which the MT lattice serves as a platform that integrates internal tubulin signals, such as nucleotide state, with outside signals, such as binding of MAPs. These global lattice rearrangements in turn affect the affinity of other MT partners and result in the exquisite regulation of the MT dynamics. Microtubules (MTs) are polymers assembled from αβ-tubulin heterodimers that display the hallmark behavior of dynamic instability. MT dynamics are driven by GTP hydrolysis within the MT lattice, and are highly regulated by a number of MT-associated proteins (MAPs). How MAPs affect MTs is still not fully understood, partly due to a lack of high-resolution structural data on undecorated MTs, which need to serve as a baseline for further comparisons. Here we report three structures of MTs in different nucleotide states (GMPCPP, GDP, and GTPγS) at near-atomic resolution and in the absence of any binding proteins. These structures allowed us to differentiate the effects of nucleotide state versus MAP binding on MT structure. Kinesin binding has a small effect on the extended, GMPCPP-bound lattice, but hardly affects the compacted GDP-MT lattice, while binding of end-binding (EB) proteins can induce lattice compaction (together with lattice twist) in MTs that were initially in an extended and more stable state. We propose a MT lattice-centric model in which the MT lattice serves as a platform that integrates internal tubulin signals, such as nucleotide state, with outside signals, such as binding of MAPs or mechanical forces, resulting in global lattice rearrangements that in turn affect the affinity of other MT partners and result in the exquisite regulation of MT dynamics.
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234
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Mphahlele MJ, Parbhoo N. Synthesis, Evaluation of Cytotoxicity and Molecular Docking Studies of the 7-Acetamido Substituted 2-Aryl-5-bromo-3-trifluoroacetylindoles as Potential Inhibitors of Tubulin Polymerization. Pharmaceuticals (Basel) 2018; 11:ph11020059. [PMID: 29891753 PMCID: PMC6027433 DOI: 10.3390/ph11020059] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 05/22/2018] [Accepted: 05/25/2018] [Indexed: 02/07/2023] Open
Abstract
The 3-trifluoroacetyl⁻substituted 7-acetamido-2-aryl-5-bromoindoles 5a⁻h were prepared and evaluated for potential antigrowth effect in vitro against human lung cancer (A549) and cervical cancer (HeLa) cells and for the potential to inhibit tubulin polymerization. The corresponding intermediates, namely, the 3-unsubstituted 7-acetyl-2-aryl-5-bromoindole 2a⁻d and 7-acetamido-2-aryl-5-bromoindole 4a⁻d were included in the assays in order to correlate both structural variations and cytotoxicity. No cytotoxicity was observed for compounds 2a⁻d and their 3-trifluoroacetyl⁻substituted derivatives 5a⁻d against both cell lines. The 7-acetamido derivatives 4⁻d exhibited modest cytotoxicity against both cell lines. All of the 3-trifluoroacetyl⁻substituted 7-acetamido-2-aryl-5-bromoindoles 5e⁻h were found to be more active against both cell lines when compared to the chemotherapeutic drug, Melphalan. The most active compound, 5g, induced programmed cell death (apoptosis) in a caspase-dependent manner for both A549 and HeLa cells. Compounds 5e⁻h were found to significantly inhibit tubulin polymerization against indole-3-carbinol and colchicine as reference standards. Molecular docking of 5g into the colchicine-binding site suggests that the compounds bind to tubulin by different type of interactions including pi-alkyl, amide-pi stacked and alkyl interactions as well as hydrogen bonding with the protein residues to elicit anticancer activity.
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Affiliation(s)
- Malose J Mphahlele
- Department of Chemistry, College of Science, Engineering and Technology, University of South Africa, Private Bag X06, Florida 1710, South Africa.
| | - Nishal Parbhoo
- Department of Life & Consumer Sciences, College of Agriculture and Environmental Sciences, University of South Africa, Private Bag X06, Florida 1710, South Africa.
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235
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Manandhar A, Kang M, Chakraborty K, Loverde SM. Effect of Nucleotide State on the Protofilament Conformation of Tubulin Octamers. J Phys Chem B 2018; 122:6164-6178. [PMID: 29768004 DOI: 10.1021/acs.jpcb.8b02193] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
At the molecular level, the dynamic instability (random growth and shrinkage) of the microtubule (MT) is driven by the nucleotide state (GTP vs GDP) in the β subunit of the tubulin dimers at the MT cap. Here, we use large-scale molecular dynamics (MD) simulations and normal-mode analysis (NMA) to characterize the effect of a single GTP cap layer on tubulin octamers composed of two neighboring protofilaments (PFs). We utilize recently reported high-resolution structures of dynamic MTs to simulate a GDP octamer both with and without a single GTP cap layer. We perform multiple replicas of long-time atomistic MD simulations (3 replicas, 0.3 μs for each replica, 0.9 μs for each octamer system, and 1.8 μs total) of both octamers. We observe that a single GTP cap layer induces structural differences in neighboring PFs, finding that one PF possesses a gradual curvature, compared to the second PF which possesses a kinked conformation. This results in either curling or splaying between these PFs. We suggest that this is due to asymmetric strengths of longitudinal contacts between the two PFs. Furthermore, using NMA, we calculate mechanical properties of these octamer systems and find that octamer system with a single GTP cap layer possesses a lower flexural rigidity.
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Affiliation(s)
- Anjela Manandhar
- Department of Chemistry, College of Staten Island , City University of New York , 2800 Victory Boulevard , Staten Island , New York 10314 , United States.,Ph.D. Program in Biochemistry , The Graduate Center of the City University of New York , 365 Fifth Avenue , New York , New York 10016 , United States
| | - Myungshim Kang
- Department of Chemistry, College of Staten Island , City University of New York , 2800 Victory Boulevard , Staten Island , New York 10314 , United States
| | - Kaushik Chakraborty
- Department of Chemistry, College of Staten Island , City University of New York , 2800 Victory Boulevard , Staten Island , New York 10314 , United States
| | - Sharon M Loverde
- Department of Chemistry, College of Staten Island , City University of New York , 2800 Victory Boulevard , Staten Island , New York 10314 , United States.,Ph.D. Program in Biochemistry , The Graduate Center of the City University of New York , 365 Fifth Avenue , New York , New York 10016 , United States
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236
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Microtubule-Targeting Agents: Strategies To Hijack the Cytoskeleton. Trends Cell Biol 2018; 28:776-792. [PMID: 29871823 DOI: 10.1016/j.tcb.2018.05.001] [Citation(s) in RCA: 291] [Impact Index Per Article: 48.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 05/01/2018] [Accepted: 05/08/2018] [Indexed: 11/20/2022]
Abstract
Microtubule-targeting agents (MTAs) such as paclitaxel and the vinca alkaloids are among the most important medical weapons available to combat cancer. MTAs interfere with intracellular transport, inhibit eukaryotic cell proliferation, and promote cell death by suppressing microtubule dynamics. Recent advances in the structural analysis of MTAs have enabled the extensive characterization of their interactions with microtubules and their building block tubulin. We review here our current knowledge on the molecular mechanisms used by MTAs to hijack the microtubule cytoskeleton, and discuss dual inhibitors that target both kinases and microtubules. We further formulate some outstanding questions related to MTA structural biology and present possible routes for future investigations of this fascinating class of antimitotic agents.
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237
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Singh H, Wray N, Schappi JM, Rasenick MM. Disruption of lipid-raft localized Gα s/tubulin complexes by antidepressants: a unique feature of HDAC6 inhibitors, SSRI and tricyclic compounds. Neuropsychopharmacology 2018; 43:1481-1491. [PMID: 29463911 PMCID: PMC5983546 DOI: 10.1038/s41386-018-0016-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 01/11/2018] [Accepted: 01/18/2018] [Indexed: 01/06/2023]
Abstract
Current antidepressant therapies meet with variable therapeutic success and there is increasing interest in therapeutic approaches not based on monoamine signaling. Histone deacetylase 6 (HDAC6), which also deacetylates α-tubulin shows altered expression in mood disorders and HDAC6 knockout mice mimic traditional antidepressant treatments. Nonetheless, a mechanistic understanding for HDAC6 inhibitors in the treatment of depression remains elusive. Previously, we have shown that sustained treatment of rats or glioma cells with several antidepressants translocates Gαs from lipid rafts toward increased association with adenylyl cyclase (AC). Concomitant with this is a sustained increase in cAMP production. While Gαs modifies microtubule dynamics, tubulin also acts as an anchor for Gαs in lipid-rafts. Since HDAC-6 inhibitors potentiate α-tubulin acetylation, we hypothesize that acetylation of α-tubulin disrupts tubulin-Gαs raft-anchoring, rendering Gαs free to activate AC. To test this, C6 Glioma (C6) cells were treated with the HDAC-6 inhibitor, tubastatin-A. Chronic treatment with tubastatin-A not only increased α-tubulin acetylation but also translocated Gαs from lipid-rafts, without changing total Gαs. Reciprocally, depletion of α-tubulin acetyl-transferase-1 ablated this phenomenon. While escitalopram and imipramine also disrupt Gαs/tubulin complexes and translocate Gαs from rafts, they evoke no change in tubulin acetylation. Finally, two indicators of downstream cAMP signaling, cAMP response element binding protein phosphorylation (pCREB) and expression of brain-derived-neurotrophic-factor (BDNF) were both elevated by tubastatin-A. These findings suggest HDAC6 inhibitors show a cellular profile resembling traditional antidepressants, but have a distinct mode of action. They also reinforce the validity of antidepressant-induced Gαs translocation from lipid-rafts as a biosignature for antidepressant response that may be useful in the development of new antidepressant compounds.
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Affiliation(s)
- Harinder Singh
- 0000 0001 2175 0319grid.185648.6Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, IL 60612 USA
| | - Nathan Wray
- 0000 0001 2175 0319grid.185648.6Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, IL 60612 USA
| | - Jeffrey M. Schappi
- 0000 0001 2175 0319grid.185648.6Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, IL 60612 USA
| | - Mark M. Rasenick
- 0000 0001 2175 0319grid.185648.6Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, IL 60612 USA ,0000 0001 2175 0319grid.185648.6Department of Psychiatry, University of Illinois at Chicago, Chicago, IL 60612 USA ,Jesse Brown VAMC, Chicago, IL 60612 USA
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238
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Wang JD, Wang YR, Wang YZ, Wang WZ, Wang R, Gao SJ. RNA interference of tubulin genes has lethal effects in Mythimna separate. Gene 2018; 670:1-6. [PMID: 29802997 DOI: 10.1016/j.gene.2018.05.094] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2018] [Revised: 05/21/2018] [Accepted: 05/23/2018] [Indexed: 01/12/2023]
Abstract
RNAi (RNA interference) is a technology for silencing expression of target genes via sequence-specific double-stranded RNA (dsRNA). Recently, dietary introduction of bacterially expressed dsRNA has shown great potential in the field of pest management. Identification of potential candidate genes for RNAi is the first step in this application. The oriental armyworm, Mythimna separata Walker (Lepidoptera: Noctuidae) is a polyphagous, migratory pest, and outbreaks have led to severe crop damage in China. In the present study, two tubulin genes were chosen as target genes because of their crucial role in insect development. Both Msα-tubulin and Msβ-tubulin genes are expressed across all life stages and are highly expressed in the head and epidermis. Feeding of bacterially expressed dsRNA of Msα-tubulin and Msβ-tubulin to third-instar larvae knocked down target mRNAs. A lethal phenotype was observed with knockdown of Msα-tubulin and Msβ-tubulin concurrent with reduction in body weight. Bacterially expressed dsRNA can be used to control M. separata, and tubulin genes could be effective candidate genes for an RNAi-based control strategy of this pest.
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Affiliation(s)
- Jin-da Wang
- National Engineering Research Center of Sugarcane, Fujian Agricultural and Forestry University, Fuzhou 350002, China.
| | - Ya-Ru Wang
- National Engineering Research Center of Sugarcane, Fujian Agricultural and Forestry University, Fuzhou 350002, China
| | - Yong-Zhi Wang
- National Engineering Research Center of Sugarcane, Fujian Agricultural and Forestry University, Fuzhou 350002, China
| | - Wei-Zhong Wang
- National Engineering Research Center of Sugarcane, Fujian Agricultural and Forestry University, Fuzhou 350002, China
| | - Rong Wang
- College of Forestry, Fujian Agricultural and Forestry University, Fuzhou 350002, China.
| | - San-Ji Gao
- National Engineering Research Center of Sugarcane, Fujian Agricultural and Forestry University, Fuzhou 350002, China
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239
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Joachimiak E, Jerka‐Dziadosz M, Krzemień‐Ojak Ł, Wacławek E, Jedynak K, Urbanska P, Brutkowski W, Sas‐Nowosielska H, Fabczak H, Gaertig J, Wloga D. Multiple phosphorylation sites on γ‐tubulin are essential and contribute to the biogenesis of basal bodies in
Tetrahymena. J Cell Physiol 2018; 233:8648-8665. [DOI: 10.1002/jcp.26742] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Accepted: 04/09/2018] [Indexed: 12/11/2022]
Affiliation(s)
- Ewa Joachimiak
- Laboratory of Cytoskeleton and Cilia BiologyDepartment of Cell BiologyNencki Institute of Experimental Biology of Polish Academy of SciencesWarsawPoland
| | - Maria Jerka‐Dziadosz
- Laboratory of Cytoskeleton and Cilia BiologyDepartment of Cell BiologyNencki Institute of Experimental Biology of Polish Academy of SciencesWarsawPoland
| | - Łucja Krzemień‐Ojak
- Laboratory of Cytoskeleton and Cilia BiologyDepartment of Cell BiologyNencki Institute of Experimental Biology of Polish Academy of SciencesWarsawPoland
| | - Ewa Wacławek
- Laboratory of Cytoskeleton and Cilia BiologyDepartment of Cell BiologyNencki Institute of Experimental Biology of Polish Academy of SciencesWarsawPoland
| | - Katarzyna Jedynak
- Faculty of BiologyDepartment of Animal PhysiologyInstitute of ZoologyUniversity of WarsawWarsawPoland
| | - Paulina Urbanska
- Laboratory of Cytoskeleton and Cilia BiologyDepartment of Cell BiologyNencki Institute of Experimental Biology of Polish Academy of SciencesWarsawPoland
| | - Wojciech Brutkowski
- Laboratory of Imaging Tissue Structure and FunctionNencki Institute of Experimental Biology of Polish Academy of SciencesWarsawPoland
| | - Hanna Sas‐Nowosielska
- Laboratory of Imaging Tissue Structure and FunctionNencki Institute of Experimental Biology of Polish Academy of SciencesWarsawPoland
| | - Hanna Fabczak
- Laboratory of Cytoskeleton and Cilia BiologyDepartment of Cell BiologyNencki Institute of Experimental Biology of Polish Academy of SciencesWarsawPoland
| | - Jacek Gaertig
- Department of Cellular BiologyUniversity of GeorgiaAthensGeorgia
| | - Dorota Wloga
- Laboratory of Cytoskeleton and Cilia BiologyDepartment of Cell BiologyNencki Institute of Experimental Biology of Polish Academy of SciencesWarsawPoland
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240
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Karar M, Paul S, Biswas B, Majumdar T, Mallick A. A newly developed highly selective Zn 2+-AcO - ion-pair sensor through partner preference: equal efficiency under solitary and colonial situation. Dalton Trans 2018; 47:7059-7069. [PMID: 29744514 DOI: 10.1039/c8dt00362a] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Unusual self-sorting of an ion-pair under highly crowded conditions driven by a synthesized intelligent molecule 2-((E)-(3-((E)-2-hydroxy-3-methoxybenzylideneamino)-2-hydroxypropyl imino)methyl)-6-methoxyphenol, hereafter HBP, is described. When a mixture of various metal salts was allowed to react with HBP, only a specific ion-pair ZnII/AcO- in the solution simultaneously reacted, resulting in high-fidelity ion-pair recognition of HBP. This phenomenon was evidenced by significant changes in the absorption spectra and huge enhancement in emission intensity of HBP. The property that one molecule preferring one particular cation-anion pair over others is a rare but interesting phenomenon. Thus, the potential to interact selectively with the targeted ion-pair resulting in the formation of a specific complex recognized HBP as a new class of molecule that might find future applications in real time and on-site monitoring and separation of new molecules.
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Affiliation(s)
- Monaj Karar
- Department of Chemistry, University of Kalyani, Nadia, West Bengal 741235, India.
| | - Suvendu Paul
- Department of Chemistry, University of Kalyani, Nadia, West Bengal 741235, India.
| | - Bhaskar Biswas
- Department of Chemistry, Surendranath College, Kolkata, West Bengal 700009, India
| | - Tapas Majumdar
- Department of Chemistry, University of Kalyani, Nadia, West Bengal 741235, India.
| | - Arabinda Mallick
- Department of Chemistry, Kashipur Michael Madhusudan Mahavidyalaya, Purulia, West Bengal 723132, India.
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241
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Chu S, Baker MR, Leong G, Letcher RJ, Li QX. Covalent binding of the organophosphate insecticide profenofos to tyrosine on α- and β-tubulin proteins. CHEMOSPHERE 2018; 199:154-159. [PMID: 29433029 PMCID: PMC5847477 DOI: 10.1016/j.chemosphere.2018.02.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Revised: 01/31/2018] [Accepted: 02/01/2018] [Indexed: 06/08/2023]
Abstract
Organophosphorus (OP) compounds can bind covalently to many types of proteins and form protein adducts. These protein adducts can indicate the exposure to and neurotoxicity of OPs. In the present work, we studied adduction of tubulin with the OP insecticide profenofos in vitro and optimized the method for detection of adducted peptides. Porcine tubulin was incubated with profenofos and was then digested with trypsin, followed by mass spectrometric identification of the profenofos-modified tubulin and binding sites. With solvent-assisted digestion (80% acetonitrile in digestion solution), the protein was digested for peptide identification, especially for some peptides with low mass. The MALDI-TOF-MS and LC-ESI-TOF-MS analysis results showed that profenofos bound covalently to Tyr83 in porcine α-tubulin (TGTY*83R) and to Tyr281 in porcine β-tubulin (GSQQY*281R) with a mass increase of 166.02 Da from the original peptide fragments of porcine tubulin proteins. Tyrosine adduct sites were also confirmed by MALDI-TOF/TOF-MS analysis. This result may partially explain the neurotoxicity of profenofos at low doses and prolonged periods of exposure.
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Affiliation(s)
- Shaogang Chu
- Ecotoxicology and Wildlife Health Division, Wildlife and Landscape Science Directorate, National Wildlife Research Centre, Environment and Climate Change Canada, 1125 Colonel By Dr., Carleton University, Ottawa, ON, K1A 0H3, Canada
| | - Margaret R Baker
- Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, 1955 East West Road, Honolulu, HI, 96822, USA
| | - Gladys Leong
- Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, 1955 East West Road, Honolulu, HI, 96822, USA
| | - Robert J Letcher
- Ecotoxicology and Wildlife Health Division, Wildlife and Landscape Science Directorate, National Wildlife Research Centre, Environment and Climate Change Canada, 1125 Colonel By Dr., Carleton University, Ottawa, ON, K1A 0H3, Canada
| | - Qing X Li
- Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, 1955 East West Road, Honolulu, HI, 96822, USA.
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242
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Bachand GD, Jain R, Ko R, Bouxsein NF, VanDelinder V. Inhibition of Microtubule Depolymerization by Osmolytes. Biomacromolecules 2018; 19:2401-2408. [PMID: 29689154 DOI: 10.1021/acs.biomac.7b01799] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Microtubule dynamics play a critical role in the normal physiology of eukaryotic cells as well as a number of cancers and neurodegenerative disorders. The polymerization/depolymerization of microtubules is regulated by a variety of stabilizing and destabilizing factors, including microtubule-associated proteins and therapeutic agents (e.g., paclitaxel, nocodazole). Here we describe the ability of the osmolytes polyethylene glycol (PEG) and trimethylamine- N-oxide (TMAO) to inhibit the depolymerization of individual microtubule filaments for extended periods of time (up to 30 days). We further show that PEG stabilizes microtubules against both temperature- and calcium-induced depolymerization. Our results collectively suggest that the observed inhibition may be related to combination of the kosmotropic behavior and excluded volume/osmotic pressure effects associated with PEG and TMAO. Taken together with prior studies, our data suggest that the physiochemical properties of the local environment can regulate microtubule depolymerization and may potentially play an important role in in vivo microtubule dynamics.
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Affiliation(s)
- George D Bachand
- Center for Integrated Nanotechnologies , Sandia National Laboratories , P.O. Box 5800, MS 1303, Albuquerque , New Mexico 87185 , United States
| | - Rishi Jain
- Center for Integrated Nanotechnologies , Sandia National Laboratories , P.O. Box 5800, MS 1303, Albuquerque , New Mexico 87185 , United States
| | - Randy Ko
- Center for Integrated Nanotechnologies , Sandia National Laboratories , P.O. Box 5800, MS 1303, Albuquerque , New Mexico 87185 , United States
| | - Nathan F Bouxsein
- Center for Integrated Nanotechnologies , Sandia National Laboratories , P.O. Box 5800, MS 1303, Albuquerque , New Mexico 87185 , United States
| | - Virginia VanDelinder
- Center for Integrated Nanotechnologies , Sandia National Laboratories , P.O. Box 5800, MS 1303, Albuquerque , New Mexico 87185 , United States
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Abstract
Microtubules, constituted by end-to-end negatively charged α- and β-tubulin dimers, are long, hollow, pseudohelical cylinders with internal and external diameters of about 16 and 26 nm, respectively, and widely exist in cell cytoplasm, neuron axons, and dendrites. Although their structural functions in physiological processes, such as cell mitosis, cell motility, and motor protein transport, have been widely accepted, their role in neuron activity remains attractively elusive. Here we show a new function of microtubules: they can generate instant response to a calcium pulse because of their specific permeability for ions. Our comprehensive simulations from all-atom molecular dynamics to potential of mean force and continuum modeling reveal that K+ and Na+ ions can permeate through the nanopores in the microtubule wall easily, while Ca2+ ions are blocked by the wall with a much higher free energy barrier. These cations are adsorbed to the surfaces of the wall with affinity decreasing in the sequence Ca2+, Na+, and K+. As a result, when the concentration of Ca2+ ions increases outside the microtubule during neuronal excitation, K+ and Na+ ions will be driven into the microtubule, triggering subsequent axial ion redistribution within the microtubule. The results shed light on the possibility of the ion-permeable microtubules being involved in neural signal processing.
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Affiliation(s)
- Chun Shen
- State Key Laboratory of Mechanics and Control of Mechanical Structure and Key Laboratory for Intelligent Nano Materials and Devices of the Ministry of Education, and Institute of Nanoscience , Nanjing University of Aeronautics and Astronautics , Nanjing 210016 , China
| | - Wanlin Guo
- State Key Laboratory of Mechanics and Control of Mechanical Structure and Key Laboratory for Intelligent Nano Materials and Devices of the Ministry of Education, and Institute of Nanoscience , Nanjing University of Aeronautics and Astronautics , Nanjing 210016 , China
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244
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Igaev M, Grubmüller H. Microtubule assembly governed by tubulin allosteric gain in flexibility and lattice induced fit. eLife 2018; 7:34353. [PMID: 29652248 PMCID: PMC5945277 DOI: 10.7554/elife.34353] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 04/12/2018] [Indexed: 11/24/2022] Open
Abstract
Microtubules (MTs) are key components of the cytoskeleton and play a central role in cell division and development. MT assembly is known to be associated with a structural change in αβ-tubulin dimers from kinked to straight conformations. How GTP binding renders individual dimers polymerization-competent, however, is still unclear. Here, we have characterized the conformational dynamics and energetics of unassembled tubulin using atomistic molecular dynamics and free energy calculations. Contrary to existing allosteric and lattice models, we find that GTP-tubulin favors a broad range of almost isoenergetic curvatures, whereas GDP-tubulin has a much lower bending flexibility. Moreover, irrespective of the bound nucleotide and curvature, two conformational states exist differing in location of the anchor point connecting the monomers that affects tubulin bending, with one state being strongly favored in solution. Our findings suggest a new combined model in which MTs incorporate and stabilize flexible GTP-dimers with a specific anchor point state.
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Affiliation(s)
- Maxim Igaev
- Department of Theoretical and Computational Biophysics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Helmut Grubmüller
- Department of Theoretical and Computational Biophysics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
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245
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Atherton J, Stouffer M, Francis F, Moores CA. Microtubule architecture in vitro and in cells revealed by cryo-electron tomography. ACTA CRYSTALLOGRAPHICA SECTION D-STRUCTURAL BIOLOGY 2018; 74:572-584. [PMID: 29872007 PMCID: PMC6096491 DOI: 10.1107/s2059798318001948] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Accepted: 02/01/2018] [Indexed: 01/03/2023]
Abstract
Electron microscopy is a key methodology for studying microtubule structure and organization. Here, the results of cryo-electron tomography experiments on in vitro-polymerized microtubules and comparisons with microtubule ultrastructure in cells are described. The microtubule cytoskeleton is involved in many vital cellular processes. Microtubules act as tracks for molecular motors, and their polymerization and depolymerization can be harnessed to generate force. The structures of microtubules provide key information about the mechanisms by which their cellular roles are accomplished and the physiological context in which these roles are performed. Cryo-electron microscopy allows the visualization of in vitro-polymerized microtubules and has provided important insights into their overall morphology and the influence of a range of factors on their structure and dynamics. Cryo-electron tomography can be used to determine the unique three-dimensional structure of individual microtubules and their ends. Here, a previous cryo-electron tomography study of in vitro-polymerized GMPCPP-stabilized microtubules is revisited, the findings are compared with new tomograms of dynamic in vitro and cellular microtubules, and the information that can be extracted from such data is highlighted. The analysis shows the surprising structural heterogeneity of in vitro-polymerized microtubules. Lattice defects can be observed both in vitro and in cells. The shared ultrastructural properties in these different populations emphasize the relevance of three-dimensional structures of in vitro microtubules for understanding microtubule cellular functions.
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Affiliation(s)
- Joseph Atherton
- Institute of Structural and Molecular Biology, Birkbeck College, Malet Street, London WC1E 7HX, England
| | | | - Fiona Francis
- INSERM UMR-S 839, 17 Rue du Fer à Moulin, 75005 Paris, France
| | - Carolyn A Moores
- Institute of Structural and Molecular Biology, Birkbeck College, Malet Street, London WC1E 7HX, England
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246
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Yang CPH, Wang C, Ojima I, Horwitz SB. Taxol Analogues Exhibit Differential Effects on Photoaffinity Labeling of β-Tubulin and the Multidrug Resistance Associated P-Glycoprotein. JOURNAL OF NATURAL PRODUCTS 2018; 81:600-606. [PMID: 29517223 PMCID: PMC6147140 DOI: 10.1021/acs.jnatprod.7b01047] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Several next-generation taxanes have been reported to possess high potency against Taxol-resistant cancer cell lines overexpressing βIII-tubulin and/or P-glycoprotein (P-gp), both of which are involved in drug resistance. Using a photoaffinity Taxol analogue, 2-( m-azidobenzoyl)taxol, two potent next-generation taxanes, SB-T-1214 and SB-CST-10202, exhibited distinct inhibitory effects on photolabeling of β-tubulin from different eukaryotic sources that differ in β-tubulin isotype composition. They also specifically inhibited photolabeling of P-gp, and the inhibitory effect correlated well with the steady-state accumulation of [3H]vinblastine in a multidrug resistant (MDR) cell line, SKVLB1. Several microtubule-stabilizing agents (MSAs)-resistant cell lines from the human ovarian cancer cell line Hey were isolated, and their MDR1 and βIII-tubulin levels determined. Distinct potencies of the two taxanes against different MSA-resistant cells expressing unique levels of MDR1 and βIII-tubulin were found. Cytotoxicity assays, done in the presence of verapamil, indicated that SB-T-1214 is a substrate, although not as good as Taxol, for P-gp. The mechanisms involved in drug resistance are multifactorial, and the effectiveness of new Taxol analogues depends on the interaction between the drugs and all possible targets; in this case the two major cellular targets are β-tubulin and P-gp.
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Affiliation(s)
- Chia-Ping Huang Yang
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York 10461, United States
- Department of Obstetrics and Gynecology and Women’s Health, Division of Gynecologic Oncology, Albert Einstein College of Medicine, Bronx, New York 10461, United States
| | - Changwei Wang
- Department of Chemistry and Institute of Chemical Biology and Drug Discovery, State University of New York at Stony Brook, Stony Brook, New York 11794, United States
| | - Iwao Ojima
- Department of Chemistry and Institute of Chemical Biology and Drug Discovery, State University of New York at Stony Brook, Stony Brook, New York 11794, United States
| | - Susan Band Horwitz
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York 10461, United States
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247
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Ojima I, Wang X, Jing Y, Wang C. Quest for Efficacious Next-Generation Taxoid Anticancer Agents and Their Tumor-Targeted Delivery. JOURNAL OF NATURAL PRODUCTS 2018; 81:703-721. [PMID: 29468872 PMCID: PMC5869464 DOI: 10.1021/acs.jnatprod.7b01012] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Indexed: 05/28/2023]
Abstract
Paclitaxel and docetaxel are among the most widely used chemotherapeutic drugs against various types of cancer. However, these drugs cause undesirable side effects as well as drug resistance. Therefore, it is essential to develop next-generation taxoid anticancer agents with better pharmacological properties and improved activity especially against drug-resistant and metastatic cancers. The SAR studies by the authors have led to the development of numerous highly potent novel second- and third-generation taxoids with systematic modifications at the C-2, C-10, and C-3' positions. The third-generation taxoids showed virtually no difference in potency against drug-resistant and drug-sensitive cell lines. Some of the next-generation taxoids also exhibited excellent potency against cancer stem cells. This account summarizes concisely investigations into taxoids over 25 years based on a strong quest for the discovery and development of efficacious next-generation taxoids. Discussed herein are SAR studies on different types of taxoids, a common pharmacophore proposal for microtubule-stabilizing anticancer agents and its interesting history, the identification of the paclitaxel binding site and its bioactive conformation, characteristics of the next-generation taxoids in cancer cell biology, including new aspects of their mechanism of action, and the highly efficacious tumor-targeted drug delivery of potent next-generation taxoids.
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Affiliation(s)
- Iwao Ojima
- Department of Chemistry and Institute
of Chemical Biology & Drug Discovery, Stony Brook University−State University of New York, Stony Brook, New York 11794-3400, United States
| | - Xin Wang
- Department of Chemistry and Institute
of Chemical Biology & Drug Discovery, Stony Brook University−State University of New York, Stony Brook, New York 11794-3400, United States
| | - Yunrong Jing
- Department of Chemistry and Institute
of Chemical Biology & Drug Discovery, Stony Brook University−State University of New York, Stony Brook, New York 11794-3400, United States
| | - Changwei Wang
- Department of Chemistry and Institute
of Chemical Biology & Drug Discovery, Stony Brook University−State University of New York, Stony Brook, New York 11794-3400, United States
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248
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Wang JT, Stearns T. The ABCs of Centriole Architecture: The Form and Function of Triplet Microtubules. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2018; 82:145-155. [PMID: 29540555 PMCID: PMC11156431 DOI: 10.1101/sqb.2017.82.034496] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/09/2024]
Abstract
The centriole is a defining feature of many eukaryotic cells. It nucleates a cilium, organizes microtubules as part of the centrosome, and is duplicated in coordination with the cell cycle. Centrioles have a remarkable structure, consisting of microtubules arranged in a barrel with ninefold radial symmetry. At their base, or proximal end, centrioles have unique triplet microtubules, formed from three microtubules linked to each other. This microtubule organization is not found anywhere else in the cell, is conserved in all major branches of the eukaryotic tree, and likely was present in the last eukaryotic common ancestor. At their tip, or distal end, centrioles have doublet microtubules, which template the cilium. Here, we consider the structures of the compound microtubules in centrioles and discuss potential mechanisms for their formation and their function. We propose that triplet microtubules are required for the structural integrity of centrioles, allowing the centriole to serve as the essential nucleator of the cilium.
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Affiliation(s)
- Jennifer T Wang
- Department of Biology, Stanford University, Stanford, California 94305-5020
| | - Tim Stearns
- Department of Biology, Stanford University, Stanford, California 94305-5020
- Department of Genetics, Stanford School of Medicine, Stanford, California 94305
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249
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Bollinger JA, Stevens MJ. Catastrophic depolymerization of microtubules driven by subunit shape change. SOFT MATTER 2018; 14:1748-1752. [PMID: 29367981 DOI: 10.1039/c7sm02033c] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Microtubules exhibit a dynamic instability between growth and catastrophic depolymerization. GTP-tubulin (αβ-dimer bound to GTP) self-assembles, but dephosphorylation of GTP- to GDP-tubulin within the tubule results in destabilization. While the mechanical basis for destabilization is not fully understood, one hypothesis is that dephosphorylation causes tubulin to change shape, frustrating bonds and generating stress. To test this idea, we perform molecular dynamics simulations of microtubules built from coarse-grained models of tubulin, incorporating a small compression of α-subunits associated with dephosphorylation in experiments. We find that this shape change induces depolymerization of otherwise stable systems via unpeeling "ram's horns" characteristic of microtubules. Depolymerization can be averted by caps with uncompressed α-subunits, i.e., GTP-rich end regions. Thus, the shape change is sufficient to yield microtubule behavior.
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Affiliation(s)
- Jonathan A Bollinger
- Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque NM 87185, USA.
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250
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α-Tubulin Acetyltransferase Is a Novel Target Mediating Neurite Growth Inhibitory Effects of Chondroitin Sulfate Proteoglycans and Myelin-Associated Glycoprotein. eNeuro 2018; 5:eN-NWR-0240-17. [PMID: 29497702 PMCID: PMC5830348 DOI: 10.1523/eneuro.0240-17.2018] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Revised: 01/17/2018] [Accepted: 01/18/2018] [Indexed: 12/24/2022] Open
Abstract
Damage to the CNS results in neuronal and axonal degeneration, and subsequent neurological dysfunction. Endogenous repair in the CNS is impeded by inhibitory chemical and physical barriers, such as chondroitin sulfate proteoglycans (CSPGs) and myelin-associated glycoprotein (MAG), which prevent axon regeneration. Previously, it has been demonstrated that the inhibition of axonal histone deacetylase-6 (HDAC6) can promote microtubule α-tubulin acetylation and restore the growth of CSPGs- and MAG-inhibited axons. Since the acetylation of α-tubulin is regulated by two opposing enzymes, HDAC6 (deacetylation) and α-tubulin acetyltransferase-1 (αTAT1; acetylation), we have investigated the regulation of these enzymes downstream of a growth inhibitory signal. Our findings show that exposure of primary mouse cortical neurons to soluble CSPGs and MAG substrates cause an acute and RhoA-kinase-dependent reduction in α-tubulin acetylation and αTAT1 protein levels, without changes to either HDAC6 levels or HDAC6 activity. The CSPGs- and MAG-induced reduction in αTAT1 occurs primarily in the distal and middle regions of neurites and reconstitution of αTAT1, either by Rho-associated kinase (ROCK) inhibition or lentiviral-mediated αTAT1 overexpression, can restore neurite growth. Lastly, we demonstrate that CSPGs and MAG signaling decreases αTAT1 levels posttranscriptionally via a ROCK-dependent increase in αTAT1 protein turnover. Together, these findings define αTAT1 as a novel potential therapeutic target for ameliorating CNS injury characterized by growth inhibitory substrates that are prohibitive to axonal regeneration.
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