1
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Wood LM, Moore JK. β3 accelerates microtubule plus end maturation through a divergent lateral interface. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.17.603993. [PMID: 39071388 PMCID: PMC11275713 DOI: 10.1101/2024.07.17.603993] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/30/2024]
Abstract
β-tubulin isotypes exhibit similar sequences but different activities, suggesting that limited sequence divergence is functionally important. We investigated this hypothesis for TUBB3/β3, a β-tubulin linked to aggressive cancers and chemoresistance in humans. We created mutant yeast strains with β-tubulin alleles that mimic variant residues in β3 and find that residues at the lateral interface are sufficient to alter microtubule dynamics and response to microtubule targeting agents. In HeLa cells, β3 overexpression decreases the lifetime of microtubule growth, and this requires residues at the lateral interface. These microtubules exhibit a shorter region of EB binding at the plus end, suggesting faster lattice maturation, and resist stabilization by paclitaxel. Resistance requires the H1-S2 and H2-S3 regions at the lateral interface of β3. Our results identify the mechanistic origins of the unique activity of β3 tubulin and suggest that tubulin isotype expression may tune the rate of lattice maturation at growing microtubule plus ends in cells.
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Affiliation(s)
- Lisa M Wood
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Jeffrey K Moore
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
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2
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Wang B, Lu Y. Collective Molecular Machines: Multidimensionality and Reconfigurability. NANO-MICRO LETTERS 2024; 16:155. [PMID: 38499833 PMCID: PMC10948734 DOI: 10.1007/s40820-024-01379-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Accepted: 02/17/2024] [Indexed: 03/20/2024]
Abstract
Molecular machines are key to cellular activity where they are involved in converting chemical and light energy into efficient mechanical work. During the last 60 years, designing molecular structures capable of generating unidirectional mechanical motion at the nanoscale has been the topic of intense research. Effective progress has been made, attributed to advances in various fields such as supramolecular chemistry, biology and nanotechnology, and informatics. However, individual molecular machines are only capable of producing nanometer work and generally have only a single functionality. In order to address these problems, collective behaviors realized by integrating several or more of these individual mechanical units in space and time have become a new paradigm. In this review, we comprehensively discuss recent developments in the collective behaviors of molecular machines. In particular, collective behavior is divided into two paradigms. One is the appropriate integration of molecular machines to efficiently amplify molecular motions and deformations to construct novel functional materials. The other is the construction of swarming modes at the supramolecular level to perform nanoscale or microscale operations. We discuss design strategies for both modes and focus on the modulation of features and properties. Subsequently, in order to address existing challenges, the idea of transferring experience gained in the field of micro/nano robotics is presented, offering prospects for future developments in the collective behavior of molecular machines.
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Affiliation(s)
- Bin Wang
- Department of Chemical Engineering, Tsinghua University, Beijing, 100084, People's Republic of China
| | - Yuan Lu
- Key Laboratory of Industrial Biocatalysis, Ministry of Education, Tsinghua University, Beijing, 100084, People's Republic of China.
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3
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Lee EJ, Gladkov N, Miller JE, Yeates TO. Design of Ligand-Operable Protein-Cages That Open Upon Specific Protein Binding. ACS Synth Biol 2024; 13:157-167. [PMID: 38133598 DOI: 10.1021/acssynbio.3c00383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2023]
Abstract
Protein nanocages have diverse applications in medicine and biotechnology, including molecular delivery. However, although numerous studies have demonstrated the ability of protein nanocages to encapsulate various molecular species, limited methods are available for subsequently opening a nanocage for cargo release under specific conditions. A modular platform with a specific protein-target-based mechanism of nanocage opening is notably lacking. To address this important technology gap, we present a new class of designed protein cages, the Ligand-Operable Cage (LOC). LOCs primarily comprise a protein nanocage core and a fused surface binding adaptor. The geometry of the LOC is designed so that binding of a target protein ligand (or multiple copies thereof) to the surface binder is sterically incompatible with retention of the assembled state of the cage. Therefore, the tight binding of a target ligand drives cage disassembly by mass action, subsequently exposing the encapsulated cargo. LOCs are modular; direct substitution of the surface binder sequence can reprogram the nanocage to open in response to any target protein ligand of interest. We demonstrate these design principles using both a natural and a designed protein cage as the core, with different proteins acting as the triggering ligand and with different reporter readouts─fluorescence unquenching and luminescence─for cage disassembly. These developments advance the critical problem of targeted molecular delivery and detection.
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Affiliation(s)
- Eric J Lee
- Department of Chemistry and Biochemistry, UCLA, Los Angeles, California 90095, United States
| | - Nika Gladkov
- Department of Chemistry and Biochemistry, UCLA, Los Angeles, California 90095, United States
| | - Justin E Miller
- Molecular Biology Institute, UCLA, Los Angeles, California 90095, United States
| | - Todd O Yeates
- Department of Chemistry and Biochemistry, UCLA, Los Angeles, California 90095, United States
- Molecular Biology Institute, UCLA, Los Angeles, California 90095, United States
- UCLA-DOE Institute for Genomics and Proteomics, UCLA, Los Angeles, California 90095, United States
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4
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Abbaali I, Truong D, Day SD, Mushayeed F, Ganesh B, Haro-Ramirez N, Isles J, Nag H, Pham C, Shah P, Tomar I, Manel-Romero C, Morrissette NS. The tubulin database: Linking mutations, modifications, ligands and local interactions. PLoS One 2023; 18:e0295279. [PMID: 38064432 PMCID: PMC10707541 DOI: 10.1371/journal.pone.0295279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Accepted: 11/20/2023] [Indexed: 12/18/2023] Open
Abstract
Microtubules are polymeric filaments, constructed of α-β tubulin heterodimers that underlie critical subcellular structures in eukaryotic organisms. Four homologous proteins (γ-, δ-, ε- and ζ-tubulin) additionally contribute to specialized microtubule functions. Although there is an immense volume of publicly available data pertaining to tubulins, it is difficult to assimilate all potentially relevant information across diverse organisms, isotypes, and categories of data. We previously assembled an extensive web-based catalogue of published missense mutations to tubulins with >1,500 entries that each document a specific substitution to a discrete tubulin, the species where the mutation was described and the associated phenotype with hyperlinks to the amino acid sequence and citation(s) for research. This report describes a significant update and expansion of our online resource (TubulinDB.bio.uci.edu) to nearly 18,000 entries. It now encompasses a cross-referenced catalog of post-translational modifications (PTMs) to tubulin drawn from public datasets, primary literature, and predictive algorithms. In addition, tubulin protein structures were used to define local interactions with bound ligands (GTP, GDP and diverse microtubule-targeting agents) and amino acids at the intradimer interface, within the microtubule lattice and with associated proteins. To effectively cross-reference these datasets, we established a universal tubulin numbering system to map entries into a common framework that accommodates specific insertions and deletions to tubulins. Indexing and cross-referencing permitted us to discern previously unappreciated patterns. We describe previously unlinked observations of loss of PTM sites in the context of cancer cells and tubulinopathies. Similarly, we expanded the set of clinical substitutions that may compromise MAP or microtubule-motor interactions by collecting tubulin missense mutations that alter amino acids at the interface with dynein and doublecortin. By expanding the database as a curated resource, we hope to relate model organism data to clinical findings of pathogenic tubulin variants. Ultimately, we aim to aid researchers in hypothesis generation and design of studies to dissect tubulin function.
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Affiliation(s)
- Izra Abbaali
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA, United States of America
| | - Danny Truong
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA, United States of America
| | - Shania Deon Day
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA, United States of America
| | - Faliha Mushayeed
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA, United States of America
| | - Bhargavi Ganesh
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA, United States of America
| | - Nancy Haro-Ramirez
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA, United States of America
| | - Juliet Isles
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA, United States of America
| | - Hindol Nag
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA, United States of America
| | - Catherine Pham
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA, United States of America
| | - Priya Shah
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA, United States of America
| | - Ishaan Tomar
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA, United States of America
| | - Carolina Manel-Romero
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA, United States of America
| | - Naomi S. Morrissette
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA, United States of America
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5
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Ciulla MG, Massironi A, Sugni M, Ensign MA, Marzorati S, Forouharshad M. Recent Advances in the Development of Biomimetic Materials. Gels 2023; 9:833. [PMID: 37888406 PMCID: PMC10606425 DOI: 10.3390/gels9100833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 10/12/2023] [Accepted: 10/17/2023] [Indexed: 10/28/2023] Open
Abstract
In this review, we focused on recent efforts in the design and development of materials with biomimetic properties. Innovative methods promise to emulate cell microenvironments and tissue functions, but many aspects regarding cellular communication, motility, and responsiveness remain to be explained. We photographed the state-of-the-art advancements in biomimetics, and discussed the complexity of a "bottom-up" artificial construction of living systems, with particular highlights on hydrogels, collagen-based composites, surface modifications, and three-dimensional (3D) bioprinting applications. Fast-paced 3D printing and artificial intelligence, nevertheless, collide with reality: How difficult can it be to build reproducible biomimetic materials at a real scale in line with the complexity of living systems? Nowadays, science is in urgent need of bioengineering technologies for the practical use of bioinspired and biomimetics for medicine and clinics.
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Affiliation(s)
- Maria G. Ciulla
- Department of Chemistry, Università degli Studi di Milano, Via C. Golgi 19, 20133 Milan, Italy
| | - Alessio Massironi
- Department of Environmental Science and Policy, Università degli Studi di Milano, Via Celoria 2, 20133 Milan, Italy
| | - Michela Sugni
- Department of Environmental Science and Policy, Università degli Studi di Milano, Via Celoria 2, 20133 Milan, Italy
| | - Matthew A. Ensign
- Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA
| | - Stefania Marzorati
- Department of Environmental Science and Policy, Università degli Studi di Milano, Via Celoria 2, 20133 Milan, Italy
| | - Mahdi Forouharshad
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
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6
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Chew YM, Cross RA. Taxol acts differently on different tubulin isotypes. Commun Biol 2023; 6:946. [PMID: 37717119 PMCID: PMC10505170 DOI: 10.1038/s42003-023-05306-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Accepted: 08/31/2023] [Indexed: 09/18/2023] Open
Abstract
Taxol is a small molecule effector that allosterically locks tubulin into the microtubule lattice. We show here that taxol has different effects on different single-isotype microtubule lattices. Using in vitro reconstitution, we demonstrate that single-isotype α1β4 GDP-tubulin lattices are stabilised and expanded by 10 µM taxol, as reported by accelerated microtubule gliding in kinesin motility assays, whereas single-isotype α1β3 GDP-tubulin lattices are stabilised but not expanded. This isotype-specific action of taxol drives gliding of segmented-isotype GDP-taxol microtubules along convoluted, sinusoidal paths, because their expanded α1β4 segments try to glide faster than their compacted α1β3 segments. In GMPCPP, single-isotype α1β3 and α1β4 lattices both show accelerated gliding, indicating that both can in principle be driven to expand. We therefore propose that taxol-induced lattice expansion requires a higher taxol occupancy than taxol-induced stabilisation, and that higher taxol occupancies are accessible to α1β4 but not α1β3 single-isotype lattices.
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Affiliation(s)
- Yean Ming Chew
- Centre for Mechanochemical Cell Biology, Warwick Medical School, Coventry, CV4 7LA, UK
| | - Robert A Cross
- Centre for Mechanochemical Cell Biology, Warwick Medical School, Coventry, CV4 7LA, UK.
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7
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Palicha KA, Loganathan P, Sudha V, Harinipriya S. Monte Carlo simulation and experimental validation of plant microtubules cathode in biodegradable battery. Sci Rep 2023; 13:10393. [PMID: 37369685 DOI: 10.1038/s41598-023-36902-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Accepted: 06/12/2023] [Indexed: 06/29/2023] Open
Abstract
For the first time, electrochemical methods are utilized to study the response of tubulin monomers (extracted from plant source such as Green Peas: Arachis Hypogea) towards charge perturbations in the form of conductivity, conformational changes via self-assembly and adsorption on Au surface. The obtained dimerization and surface adsorption energetics of the tubulins from Cyclic Voltammetry agree well with the literature value of 6.9 and 14.9 kCal/mol for lateral and longitudinal bond formation energy respectively. In addition to the effects of charge perturbations on change in structure, ionic and electronic conductivity of tubulin with increasing load are investigated and found to be 1.25 Sm-1 and 2.89 mSm-1 respectively. The electronic conductivity is 1.93 times higher than the literature value of 1.5 mSm-1, demonstrating the fact that the microtubules (dimer of tubulins, MTs) from plant source can be used as a semiconductor electrode material in energy conversion and storage applications. Thus, motivated by the Monte Carlo simulation and electrochemical results the MTs extracted from plant source are used as cathode material for energy storage device such as Bio-battery and the Galvanostatic Charge/Discharge studies are carried out in coin cell configuration. The configuration of the bio-battery cell is as follows: Al/CB//PP-1M KCl//MTs/SS; where SS and Al are used as current collectors for cathode and anode respectively, Polypropylene (PP) membrane soaked in 1M KCl as electrolyte and Carbon Black (CB) is the anode material. Another configuration of the cell would be replacement of CB by biopolymer such as ethyl cellulose anode (Al/EC/PP-1M KCl/MTs/SS).
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Affiliation(s)
- Kaushik A Palicha
- Research and Development Center, Ram Charan Co Pvt Ltd - Entity1, Chennai, Tamilnadu, 600 002, India
| | - Pavithra Loganathan
- Department of Physics and Nanotechnology, SRMIST, Kattankulathur, Chennai, Tamilnadu, 603203, India
| | - V Sudha
- Department of Chemistry, SRMIST, Kattankulathur, Chennai, Tamilnadu, 603203, India.
| | - S Harinipriya
- Research and Development Center, Ram Charan Co Pvt Ltd - Entity1, Chennai, Tamilnadu, 600 002, India.
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8
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Kalra A, Benny A, Travis SM, Zizzi EA, Morales-Sanchez A, Oblinsky DG, Craddock TJA, Hameroff SR, MacIver MB, Tuszyński JA, Petry S, Penrose R, Scholes GD. Electronic Energy Migration in Microtubules. ACS CENTRAL SCIENCE 2023; 9:352-361. [PMID: 36968538 PMCID: PMC10037452 DOI: 10.1021/acscentsci.2c01114] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Indexed: 05/29/2023]
Abstract
The repeating arrangement of tubulin dimers confers great mechanical strength to microtubules, which are used as scaffolds for intracellular macromolecular transport in cells and exploited in biohybrid devices. The crystalline order in a microtubule, with lattice constants short enough to allow energy transfer between amino acid chromophores, is similar to synthetic structures designed for light harvesting. After photoexcitation, can these amino acid chromophores transfer excitation energy along the microtubule like a natural or artificial light-harvesting system? Here, we use tryptophan autofluorescence lifetimes to probe energy hopping between aromatic residues in tubulin and microtubules. By studying how the quencher concentration alters tryptophan autofluorescence lifetimes, we demonstrate that electronic energy can diffuse over 6.6 nm in microtubules. We discover that while diffusion lengths are influenced by tubulin polymerization state (free tubulin versus tubulin in the microtubule lattice), they are not significantly altered by the average number of protofilaments (13 versus 14). We also demonstrate that the presence of the anesthetics etomidate and isoflurane reduce exciton diffusion. Energy transport as explained by conventional Förster theory (accommodating for interactions between tryptophan and tyrosine residues) does not sufficiently explain our observations. Our studies indicate that microtubules are, unexpectedly, effective light harvesters.
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Affiliation(s)
- Aarat
P. Kalra
- Department
of Chemistry, New Frick Chemistry Building, Princeton University, Princeton, New Jersey08544, United States
| | - Alfy Benny
- Department
of Chemistry, New Frick Chemistry Building, Princeton University, Princeton, New Jersey08544, United States
| | - Sophie M. Travis
- Department
of Molecular Biology, Schultz Laboratory, Princeton University, Princeton, New Jersey08544, United States
| | - Eric A. Zizzi
- Department
of Mechanical and Aerospace Engineering (DIMEAS), Politecnico di Torino, Torino10129, Italy
| | - Austin Morales-Sanchez
- Department
of Chemistry, New Frick Chemistry Building, Princeton University, Princeton, New Jersey08544, United States
| | - Daniel G. Oblinsky
- Department
of Chemistry, New Frick Chemistry Building, Princeton University, Princeton, New Jersey08544, United States
| | - Travis J. A. Craddock
- Departments
of Psychology & Neuroscience, Computer Science, and Clinical Immunology, Nova Southeastern University, Ft. Lauderdale, Florida33314, United States
| | - Stuart R. Hameroff
- Department
of Anesthesiology, Center for Consciousness Studies, University of Arizona, Tucson, Arizona85721, United States
| | - M. Bruce MacIver
- Department
of Anesthesiology, Stanford University School
of Medicine, Stanford, California94305, United States
| | - Jack A. Tuszyński
- Department
of Mechanical and Aerospace Engineering (DIMEAS), Politecnico di Torino, Torino10129, Italy
- Department
of Physics, University of Alberta, Edmonton, AlbertaT6G 2E1, Canada
- Department
of Oncology, University of Alberta, Edmonton, AlbertaT6G 1Z2, Canada
| | - Sabine Petry
- Department
of Molecular Biology, Schultz Laboratory, Princeton University, Princeton, New Jersey08544, United States
| | - Roger Penrose
- Mathematical
Institute, Andrew Wiles Building, University
of Oxford, Radcliffe Observatory Quarter, Woodstock Road, Oxford, OX2 6GG, United
Kingdom
| | - Gregory D. Scholes
- Department
of Chemistry, New Frick Chemistry Building, Princeton University, Princeton, New Jersey08544, United States
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9
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Guo W, Ale TA, Sun S, Sanchez JE, Li L. A Comprehensive Study on the Electrostatic Properties of Tubulin-Tubulin Complexes in Microtubules. Cells 2023; 12:cells12020238. [PMID: 36672172 PMCID: PMC9857020 DOI: 10.3390/cells12020238] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 12/31/2022] [Accepted: 01/02/2023] [Indexed: 01/08/2023] Open
Abstract
Microtubules are key players in several stages of the cell cycle and are also involved in the transportation of cellular organelles. Microtubules are polymerized by α/β tubulin dimers with a highly dynamic feature, especially at the plus ends of the microtubules. Therefore, understanding the interactions among tubulins is crucial for characterizing microtubule dynamics. Studying microtubule dynamics can help researchers make advances in the treatment of neurodegenerative diseases and cancer. In this study, we utilize a series of computational approaches to study the electrostatic interactions at the binding interfaces of tubulin monomers. Our study revealed that among all the four types of tubulin-tubulin binding modes, the electrostatic attractive interactions in the α/β tubulin binding are the strongest while the interactions of α/α tubulin binding in the longitudinal direction are the weakest. Our calculations explained that due to the electrostatic interactions, the tubulins always preferred to form α/β tubulin dimers. The interactions between two protofilaments are the weakest. Thus, the protofilaments are easily separated from each other. Furthermore, the important residues involved in the salt bridges at the binding interfaces of the tubulins are identified, which illustrates the details of the interactions in the microtubule. This study elucidates some mechanistic details of microtubule dynamics and also identifies important residues at the binding interfaces as potential drug targets for the inhibition of cancer cells.
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Affiliation(s)
- Wenhan Guo
- Computational Science Program, University of Texas at El Paso, El Paso, TX 79902, USA
| | - Tolulope Ayodeji Ale
- Computational Science Program, University of Texas at El Paso, El Paso, TX 79902, USA
| | - Shengjie Sun
- Computational Science Program, University of Texas at El Paso, El Paso, TX 79902, USA
| | - Jason E. Sanchez
- Computational Science Program, University of Texas at El Paso, El Paso, TX 79902, USA
| | - Lin Li
- Computational Science Program, University of Texas at El Paso, El Paso, TX 79902, USA
- Department of Physics, University of Texas at El Paso, El Paso, TX 79902, USA
- Correspondence:
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10
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Vu HT, Zhang Z, Tehver R, Thirumalai D. Plus and minus ends of microtubules respond asymmetrically to kinesin binding by a long-range directionally driven allosteric mechanism. SCIENCE ADVANCES 2022; 8:eabn0856. [PMID: 35417226 PMCID: PMC9007332 DOI: 10.1126/sciadv.abn0856] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 02/24/2022] [Indexed: 06/14/2023]
Abstract
Although it is known that majority of kinesin motors walk predominantly toward the plus end of microtubules (MTs) in a hand-over-hand manner, the structural origin of the stepping directionality is not understood. To resolve this issue, we modeled the structures of kinesin-1 (Kin1), MT, and the Kin1-MT complex using the elastic network model and calculated the residue-dependent responses to a local perturbation in the constructs. Kin1 binding elicits an asymmetric response that is pronounced in α/β-tubulin dimers in the plus end of the MT. Kin1 opens the clefts of multiple plus end α/β-tubulin dimers, creating binding-competent conformations, which is required for processivity. Reciprocally, MT induces correlations between switches I and II in the motor and enhances fluctuations in adenosine 5'-diphosphate and the residues in the binding pocket. Our findings explain both the directionality of stepping and MT effects on a key step in the catalytic cycle of kinesin.
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Affiliation(s)
- Huong T. Vu
- Centre for Mechanochemical Cell Biology, Warwick Medical School, Coventry CV4 7AL, UK
| | - Zhechun Zhang
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
| | - Riina Tehver
- Department of Physics, Denison University, Granville, OH 43023, USA
| | - D. Thirumalai
- Department of Chemistry, University of Texas, Austin, TX 78702, USA
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11
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Huang Yang CP, Horwitz SB, McDaid HM. Utilization of Photoaffinity Labeling to Investigate Binding of Microtubule Stabilizing Agents to P-Glycoprotein and β-Tubulin. JOURNAL OF NATURAL PRODUCTS 2022; 85:720-728. [PMID: 35240035 PMCID: PMC9484556 DOI: 10.1021/acs.jnatprod.2c00106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Photoaffinity labeling approaches have historically been used in pharmacology to identify molecular targets. This methodology has played a pivotal role in identifying drug-binding domains and searching for novel compounds that may interact at these domains. In this review we focus on studies of microtubule stabilizing agents of natural product origin, specifically taxol (paclitaxel). Taxol and other microtubule interacting agents bind to both P-glycoprotein (ABCB1), a drug efflux pump that reduces intracellular drug accumulation, and the tubulin/microtubule system. Both binding relationships modulate drug efficacy and are of immense interest to basic and translational scientists, primarily because of their association with drug resistance for this class of molecules. We present this body of work and acknowledge its value as fundamental to understanding the mechanisms of taxol and elucidation of the taxol pharmacophore. Furthermore, we highlight the ability to multiplex photoaffinity approaches with other technologies to further enhance our understanding of pharmacologic interactions at an atomic level. Thus, photoaffinity approaches offer a relatively inexpensive and robust technique that will continue to play an important role in drug discovery for the foreseeable future.
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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
| | - Susan Band Horwitz
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York 10461, United States
| | - Hayley M McDaid
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York 10461, United States
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York 10461, United States
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12
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Reader JC, Fan C, Ory ECH, Ju J, Lee R, Vitolo MI, Smith P, Wu S, Ching MMN, Asiedu EB, Jewell CM, Rao GG, Fulton A, Webb TJ, Yang P, Santin AD, Huang HC, Martin SS, Roque DM. Microtentacle Formation in Ovarian Carcinoma. Cancers (Basel) 2022; 14:800. [PMID: 35159067 PMCID: PMC8834106 DOI: 10.3390/cancers14030800] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 01/16/2022] [Accepted: 01/19/2022] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND The development of chemoresistance to paclitaxel and carboplatin represents a major therapeutic challenge in ovarian cancer, a disease frequently characterized by malignant ascites and extrapelvic metastasis. Microtentacles (McTNs) are tubulin-based projections observed in detached breast cancer cells. In this study, we investigated whether ovarian cancers exhibit McTNs and characterized McTN biology. METHODS We used an established lipid-tethering mechanism to suspend and image individual cancer cells. We queried a panel of immortalized serous (OSC) and clear cell (OCCC) cell lines as well as freshly procured ascites and human ovarian surface epithelium (HOSE). We assessed by Western blot β-tubulin isotype, α-tubulin post-translational modifications and actin regulatory proteins in attached/detached states. We studied clustering in suspended conditions. Effects of treatment with microtubule depolymerizing and stabilizing drugs were described. RESULTS Among cell lines, up to 30% of cells expressed McTNs. Four McTN morphologies (absent, symmetric-short, symmetric-long, tufted) were observed in immortalized cultures as well as ascites. McTN number/length varied with histology according to metastatic potential. Most OCCC overexpressed class III ß-tubulin. OCCC/OSC cell lines exhibited a trend towards more microtubule-stabilizing post-translational modifications of α-tubulin relative to HOSE. Microtubule depolymerizing drugs decreased the number/length of McTNs, confirming that McTNs are composed of tubulin. Cells that failed to form McTNs demonstrated differential expression of α-tubulin- and actin-regulating proteins relative to cells that form McTNs. Cluster formation is more susceptible to microtubule targeting agents in cells that form McTNs, suggesting a role for McTNs in aggregation. CONCLUSIONS McTNs likely participate in key aspects of ovarian cancer metastasis. McTNs represent a new therapeutic target for this disease that could refine therapies, including intraperitoneal drug delivery.
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Affiliation(s)
- Jocelyn C. Reader
- Division of Gynecologic Oncology, Greenebaum Comprehensive Cancer Center, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (J.C.R.); (C.F.); (P.S.); (M.M.N.C.); (G.G.R.)
- Department of Pharmaceutical Sciences, School of Pharmacy and Health Sciences, University of Maryland Eastern Shore, Princess Anne, MD 21853, USA
| | - Cong Fan
- Division of Gynecologic Oncology, Greenebaum Comprehensive Cancer Center, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (J.C.R.); (C.F.); (P.S.); (M.M.N.C.); (G.G.R.)
| | - Eleanor Claire-Higgins Ory
- Department of Physiology, Greenebaum Comprehensive Cancer Center, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (E.C.-H.O.); (J.J.); (R.L.)
| | - Julia Ju
- Department of Physiology, Greenebaum Comprehensive Cancer Center, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (E.C.-H.O.); (J.J.); (R.L.)
| | - Rachel Lee
- Department of Physiology, Greenebaum Comprehensive Cancer Center, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (E.C.-H.O.); (J.J.); (R.L.)
| | - Michele I. Vitolo
- Department of Pharmacology, Greenebaum Comprehensive Cancer Center, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (M.I.V.); (S.S.M.)
| | - Paige Smith
- Division of Gynecologic Oncology, Greenebaum Comprehensive Cancer Center, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (J.C.R.); (C.F.); (P.S.); (M.M.N.C.); (G.G.R.)
| | - Sulan Wu
- Department of Chemistry and Biochemistry, Oberlin College, Oberlin, OH 44074, USA;
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Mc Millan Nicol Ching
- Division of Gynecologic Oncology, Greenebaum Comprehensive Cancer Center, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (J.C.R.); (C.F.); (P.S.); (M.M.N.C.); (G.G.R.)
- Cellular and Molecular Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Division of Cancer Imaging, Russel H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins Hospital, Baltimore, MD 21287, USA
| | - Emmanuel B. Asiedu
- Department of Microbiology and Immunology, Greenebaum Comprehensive Cancer Center, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (E.B.A.); (T.J.W.)
| | - Christopher M. Jewell
- Fischell Department of Bioengineering, University of Maryland College Park, College Park, MD 20742, USA; (C.M.J.); (H.-C.H.)
- Baltimore Veterans Administration Medical Center, Baltimore, MD 21201, USA;
| | - Gautam G. Rao
- Division of Gynecologic Oncology, Greenebaum Comprehensive Cancer Center, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (J.C.R.); (C.F.); (P.S.); (M.M.N.C.); (G.G.R.)
| | - Amy Fulton
- Baltimore Veterans Administration Medical Center, Baltimore, MD 21201, USA;
- Department of Pathology, Greenebaum Comprehensive Cancer Center, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Tonya J. Webb
- Department of Microbiology and Immunology, Greenebaum Comprehensive Cancer Center, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (E.B.A.); (T.J.W.)
| | - Peixin Yang
- Department of Obstetrics, Gynecology & Reproductive Sciences and Biochemistry & Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA;
| | - Alessandro D. Santin
- Division of Gynecologic Oncology, Smilow Cancer Center, Yale University, New Haven, CT 06520, USA;
| | - Huang-Chiao Huang
- Fischell Department of Bioengineering, University of Maryland College Park, College Park, MD 20742, USA; (C.M.J.); (H.-C.H.)
| | - Stuart S. Martin
- Department of Pharmacology, Greenebaum Comprehensive Cancer Center, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (M.I.V.); (S.S.M.)
- Department of Pathology, Greenebaum Comprehensive Cancer Center, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Dana M. Roque
- Division of Gynecologic Oncology, Greenebaum Comprehensive Cancer Center, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (J.C.R.); (C.F.); (P.S.); (M.M.N.C.); (G.G.R.)
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13
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Nganfo W, Kenfack-Sadem C, Fotué A, Ekosso M, Wopunghwo S, Fai L. Dynamics of exciton polaron in microtubule. Heliyon 2022; 8:e08897. [PMID: 35265761 PMCID: PMC8899671 DOI: 10.1016/j.heliyon.2022.e08897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 11/19/2021] [Accepted: 01/31/2022] [Indexed: 11/16/2022] Open
Abstract
In this paper, we study the dynamical properties of the exciton-polaron in the microtubule. The study was carried out using a unitary transformation and an approximate diagonalization technique. Analytically, the modeling of exciton-polaron dynamics in microtubules is presented. From this model, the ground state energy, mobility, and entropy of the exciton-polaron are derived as a function of microtubule's parameters. Numerical results show that, depending on the three vibrational modes (protofilament, helix, antihelix) in MTs, exciton-polaron energy is anisotropic and is more present on the protofilament than the helix and absent on the antihelix. Taking into account the variation of the protofilament vibrations by fixing the helix vibrations, exciton-polaron moves between the 1st and 2nd protofilaments. It is seen that the variation of the two vibrations induces mobility of the quasiparticle between the 1st and 15th protofilament. This result points out the importance of helix vibrations on the dynamics of quasiparticles. It is observed that the mobility of the exciton polaron and the entropy of the system are strongly influenced by the vibrations through the protofilament and helix. The effects of the one through the antihelix is negligible. The entropy of the system is similar to that of mobility. Confirming that the quasiparticles move in the protofilament faster than in the helix.
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Affiliation(s)
- W.A. Nganfo
- Condensed Matter and Nanomaterials, Faculty of Science, Department of Physics, University of Dschang, Po Box 67, Cameroon
| | - C. Kenfack-Sadem
- Condensed Matter and Nanomaterials, Faculty of Science, Department of Physics, University of Dschang, Po Box 67, Cameroon
| | - A.J. Fotué
- Condensed Matter and Nanomaterials, Faculty of Science, Department of Physics, University of Dschang, Po Box 67, Cameroon
| | - M.C. Ekosso
- Condensed Matter and Nanomaterials, Faculty of Science, Department of Physics, University of Dschang, Po Box 67, Cameroon
| | - S.N. Wopunghwo
- Condensed Matter and Nanomaterials, Faculty of Science, Department of Physics, University of Dschang, Po Box 67, Cameroon
| | - L.C. Fai
- Condensed Matter and Nanomaterials, Faculty of Science, Department of Physics, University of Dschang, Po Box 67, Cameroon
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14
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Kliuchnikov E, Klyshko E, Kelly MS, Zhmurov A, Dima RI, Marx KA, Barsegov V. Microtubule assembly and disassembly dynamics model: Exploring dynamic instability and identifying features of Microtubules' Growth, Catastrophe, Shortening, and Rescue. Comput Struct Biotechnol J 2022; 20:953-974. [PMID: 35242287 PMCID: PMC8861655 DOI: 10.1016/j.csbj.2022.01.028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 01/26/2022] [Accepted: 01/27/2022] [Indexed: 12/21/2022] Open
Abstract
Microtubules (MTs), a cellular structure element, exhibit dynamic instability and can switch stochastically from growth to shortening; but the factors that trigger these processes at the molecular level are not understood. We developed a 3D Microtubule Assembly and Disassembly DYnamics (MADDY) model, based upon a bead-per-monomer representation of the αβ-tubulin dimers forming an MT lattice, stabilized by the lateral and longitudinal interactions between tubulin subunits. The model was parameterized against the experimental rates of MT growth and shortening, and pushing forces on the Dam1 protein complex due to protofilaments splaying out. Using the MADDY model, we carried out GPU-accelerated Langevin simulations to access dynamic instability behavior. By applying Machine Learning techniques, we identified the MT characteristics that distinguish simultaneously all four kinetic states: growth, catastrophe, shortening, and rescue. At the cellular 25 μM tubulin concentration, the most important quantities are the MT length L , average longitudinal curvatureκ long , MT tip width w , total energy of longitudinal interactions in MT latticeU long , and the energies of longitudinal and lateral interactions required to complete MT to full cylinderU long add andU lat add . At high 250 μM tubulin concentration, the most important characteristics are L ,κ long , number of hydrolyzed αβ-tubulin dimersn hyd and number of lateral interactions per helical pitchn lat in MT lattice, energy of lateral interactions in MT latticeU lat , and energy of longitudinal interactions in MT tipu long . These results allow greater insights into what brings about kinetic state stability and the transitions between states involved in MT dynamic instability behavior.
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Affiliation(s)
| | - Eugene Klyshko
- Department of Chemistry, University of Massachusetts, Lowell, MA 01854, USA
| | - Maria S. Kelly
- Department of Chemistry, University of Cincinnati, Cincinnati, OH 45221, USA
| | - Artem Zhmurov
- KTH Royal Institute of Technology, Stockholm, Sweden
| | - Ruxandra I. Dima
- Department of Chemistry, University of Cincinnati, Cincinnati, OH 45221, USA
| | - Kenneth A. Marx
- Department of Chemistry, University of Massachusetts, Lowell, MA 01854, USA
| | - Valeri Barsegov
- Department of Chemistry, University of Massachusetts, Lowell, MA 01854, USA
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15
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Garnett JA, Atherton J. Structure Determination of Microtubules and Pili: Past, Present, and Future Directions. Front Mol Biosci 2022; 8:830304. [PMID: 35096976 PMCID: PMC8795688 DOI: 10.3389/fmolb.2021.830304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 12/28/2021] [Indexed: 11/30/2022] Open
Abstract
Historically proteins that form highly polymeric and filamentous assemblies have been notoriously difficult to study using high resolution structural techniques. This has been due to several factors that include structural heterogeneity, their large molecular mass, and available yields. However, over the past decade we are now seeing a major shift towards atomic resolution insight and the study of more complex heterogenous samples and in situ/ex vivo examination of multi-subunit complexes. Although supported by developments in solid state nuclear magnetic resonance spectroscopy (ssNMR) and computational approaches, this has primarily been due to advances in cryogenic electron microscopy (cryo-EM). The study of eukaryotic microtubules and bacterial pili are good examples, and in this review, we will give an overview of the technical innovations that have enabled this transition and highlight the advancements that have been made for these two systems. Looking to the future we will also describe systems that remain difficult to study and where further technical breakthroughs are required.
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Affiliation(s)
- James A. Garnett
- Centre for Host-Microbiome Interactions, Faculty of Dental, Oral and Craniofacial Sciences, King’s College London, London, United Kingdom
| | - Joseph Atherton
- Randall Centre for Cell and Molecular Biophysics, King’s College London, London, United Kingdom
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16
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Khabudaev KV, Petrova DP, Bedoshvili YD, Likhoshway YV, Grachev MA. Molecular Evolution of Tubulins in Diatoms. Int J Mol Sci 2022; 23:618. [PMID: 35054799 PMCID: PMC8776100 DOI: 10.3390/ijms23020618] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 12/29/2021] [Accepted: 12/30/2021] [Indexed: 01/29/2023] Open
Abstract
Microtubules are formed by α- and β-tubulin heterodimers nucleated with γ-tubulin. Tubulins are conserved eukaryotic proteins. Previously, it was shown that microtubules are involved in diatom silica frustule morphogenesis. Diatom frustules are varied, and their morphology is species-specific. Despite the attractiveness of the problem of elucidating the molecular mechanisms of genetically programmed morphogenesis, the structure and evolution of diatom tubulins have not been studied previously. Based on available genomic and transcriptome data, we analyzed the phylogeny of the predicted amino acid sequences of diatom α-, β- and γ-tubulins and identified five groups for α-tubulins, six for β-tubulins and four for γ-tubulins. We identified characteristic amino acids of each of these groups and also analyzed possible posttranslational modification sites of diatom tubulins. According to our results, we assumed what changes occurred in the diatom tubulin structures during their evolution. We also identified which tubulin groups are inherent in large diatom taxa. The similarity between the evolution of diatom tubulins and the evolution of diatoms suggests that molecular changes in α-, β- and γ-tubulins could be one of the factors in the formation of a high morphological diversity of diatoms.
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Affiliation(s)
| | | | - Yekaterina D. Bedoshvili
- Limnological Institute, Siberian Branch, Russian Academy of Sciences, 664033 Irkutsk, Russia; (K.V.K.); (D.P.P.); (Y.V.L.); (M.A.G.)
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17
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Rahal A, Sharma DK, Kumar A, Sharma N, Dayal D. In silico to In vivo development of a polyherbal against Haemonchus contortus. Heliyon 2022; 8:e08789. [PMID: 35106389 PMCID: PMC8789534 DOI: 10.1016/j.heliyon.2022.e08789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 08/09/2021] [Accepted: 01/13/2022] [Indexed: 10/25/2022] Open
Abstract
Haemonchus contortus is a major constraint in the development of small ruminant subsector due to significant production losses incurred by it. The present study explores the antiparasitic potential of three anthelmintic plants (Butea monosperma, Vitex negundo and Catharanthus roseus (L.) G.Don) against H. contortus taking albendazole as the standard. In silico molecular docking and pharmacokinetic prediction studies were conducted with known bioactive molecules of these plants (palasonin, vinblastine, vincristine, betulinic acid and ursolic acid) against Glutamate Dehydrogenase (GDH) and tubulin molecules of the parasite. Methanolic extracts of these herbs were fractionated (hexane, ethyl acetate, chloroform and methanol) and used in in vitro larvicidal studies. Based on the in vitro data, two herbal prototypes were developed and clinically tested. All the 5 ligand molecules showed better binding affnity for GDH and tubulin protein as compared with albendazole and shared similar binding site in the core of the GDH hexamer with slight variations. Albendazole approximately stacked against GLY190A residue, showing hydrophobic interactions with PRO157A and a Pi-cation electrostatic interaction with ARG390 along with four hydrogen bonds. Vincristine formed 2 pi-anionic electrostatic bonds with ASP158 of B and C subunits alongwith hydrogen bonding and hydrophobic interaction and an additional pi-anion electrostatic interaction at ASP158A for vinblastine. Albendazole bound to α-tubulin next to colchicine site whereas vinblastine is bound at the nearby laulimalide/peloruside site of the dimer. Betulinic acid showed lateral interaction between the H2-H3 loop of one alpha subunit and H10 of the adjacent alpha subunit of two tubulin dimers. Ursolic acid and palasonin bound at the intradimer N site of microtubulin involving the H1-H7 and H1-H2 zone, respectively. The in vitro studies demonstrated good dose dependent anthelmintic potential. Both the prototypes were quite efficacious in clearing the infection, keeping it to a minimal for more than 5 months, probably, through direct anthelmintic effect through GDH, tubulin depolymerization and uncoupling as well as indirectly through immunomodulation along with antioxidant and anti-inflammatory properties.
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Affiliation(s)
- Anu Rahal
- Division of Animal Health, ICAR-Central Institute for Research on Goats, Makhdoom, Farah, Mathura, 281122, UP, India
| | - D K Sharma
- Division of Animal Health, ICAR-Central Institute for Research on Goats, Makhdoom, Farah, Mathura, 281122, UP, India
| | - Ashok Kumar
- Division of Animal Health, ICAR-Central Institute for Research on Goats, Makhdoom, Farah, Mathura, 281122, UP, India
| | - Nitika Sharma
- Division of Animal Health, ICAR-Central Institute for Research on Goats, Makhdoom, Farah, Mathura, 281122, UP, India
| | - Deen Dayal
- Division of Animal Health, ICAR-Central Institute for Research on Goats, Makhdoom, Farah, Mathura, 281122, UP, India
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18
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Jenardhanan P, Panneerselvam M, Mathur PP. Use of Molecular Modeling to Study Spermatogenesis: An Overview Using Proteins in Sertoli Cells. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1288:205-214. [PMID: 34453738 DOI: 10.1007/978-3-030-77779-1_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Computational structure prediction and analysis helps in understanding the structure and function of varied proteins, which otherwise becomes implausible to understand by experimental procedures. Computational techniques prove to be instrumental in understanding the molecular mechanisms that underlies physiological processes and thereby also assist in identification of potent inhibitors. Spermatogenesis, being an important cellular process that decides the fate of the progeny, holds numerous molecular interaction data, which when identified and visualized with computational structural insights, might yield a cohesive and clear-cut perception to the functionality of several proteins involved. The present chapter deals with a few selected applications of computational structure prediction towards understanding the structure of proteins and highlights how these insights are useful in providing a better understanding of different processes in spermatogenesis.
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Affiliation(s)
| | - Manivel Panneerselvam
- Department of Biotechnology, BJM School of Biosciences, Indian Institute of Technology Madras, Chennai, India
| | - Premendu P Mathur
- Department of Biochemistry & Molecular Biology, School of Life Sciences, Pondicherry University, Puducherry, India.
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19
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Bigman LS, Levy Y. Modulating Microtubules: A Molecular Perspective on the Effects of Tail Modifications. J Mol Biol 2021; 433:166988. [PMID: 33865866 DOI: 10.1016/j.jmb.2021.166988] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 04/07/2021] [Accepted: 04/07/2021] [Indexed: 10/21/2022]
Abstract
Microtubules (MTs), an essential component of the eukaryotic cytoskeleton, are a lattice of polymerized tubulin dimers and are crucial for various cellular processes. The genetic and chemical diversity of tubulin and their disordered tails gives rise to a "tubulin code". The functional role of tubulin post-translational modifications (PTMs), which contribute to the chemical diversity of the tubulin code, is gradually being unraveled. However, variation in the length and spatial organization of tubulin poly-modifications leads to an enormous combinatorial PTM space, which is difficult to study experimentally. Hence, the impact of the combinatorial tubulin PTM space on the biophysical properties of tubulin tails and their interactions with other proteins remains elusive. Here, we combine all-atom and coarse-grained molecular dynamics simulations to elucidate the biophysical implications of the large combinatorial tubulin PTM space in the context of an MT lattice. We find that tail-body interactions are more dominant in the tubulin dimer than in an MT lattice, and are more significant for the tails of α compared with β tubulin. In addition, polyglutamylation, but not polyglycylation, expands the dimensions of the tubulin tails. Polyglutamylation also leads to a decrease in the diffusion rate of MT-associated protein EB1 on MTs, while polyglycylation often increases diffusion rate. These observations are generally not sensitive to the organization of the polymodifications. The effect of PTMs on MT charge density and tail dynamics are also discussed. Overall, this study presents a molecular quantification of the biophysical properties of tubulin tails and their polymodifications, and provides predictions on the functional importance of tubulin PTMs.
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Affiliation(s)
- Lavi S Bigman
- Department of Chemical and Structural Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Yaakov Levy
- Department of Chemical and Structural Biology, Weizmann Institute of Science, Rehovot 76100, Israel.
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20
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Renauld J, Thelen N, Bartholomé O, Malgrange B, Thiry M. Dispensability of Tubulin Acetylation for 15-protofilament Microtubule Formation in the Mammalian Cochlea. Cell Struct Funct 2021; 46:11-20. [PMID: 33473065 PMCID: PMC10511047 DOI: 10.1247/csf.20057] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 12/24/2020] [Indexed: 11/11/2022] Open
Abstract
The development of hearing in mammals requires the formation and maturation of a highly organized and specialized epithelium known as the organ of Corti. This epithelium contains two types of cells, the sensory cells, which are the true receptors of auditory information, and the surrounding supporting cells, which are composed of a highly developed cytoskeleton essential to the architecture of the mature organ of Corti. The supporting cells are the only mammalian cells reported to contain the unusual 15-protofilament microtubules. In this paper, we show that 15-protofilament microtubules appear between the second and fourth day after birth in the pillar cells of the organ of Corti in mice. We also show that contrary to what has been described in the nematode worm Caenorhabiditis. elegans, microtubule acetylation is not essential for the formation of 15-protofilament microtubules in mice but is required for fine-tuning of their diameter.Key words: Acetylation, cytoskeleton, microtubule, inner ear, supporting cells.
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Affiliation(s)
- Justine Renauld
- GIGA-Neurosciences, Cell Biology Unit, University of Liège, Liège, Belgium
- Department of Otolaryngology, Case Western Reserve University, Cleveland, OH, United States of America
| | - Nicolas Thelen
- GIGA-Neurosciences, Cell Biology Unit, University of Liège, Liège, Belgium
| | - Odile Bartholomé
- GIGA-Neurosciences, Cell Biology Unit, University of Liège, Liège, Belgium
| | - Brigitte Malgrange
- GIGA-Neurosciences, Developmental Neurobiology Unit, University of Liège, Liège, Belgium
| | - Marc Thiry
- GIGA-Neurosciences, Cell Biology Unit, University of Liège, Liège, Belgium
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21
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Fourel G, Boscheron C. Tubulin mutations in neurodevelopmental disorders as a tool to decipher microtubule function. FEBS Lett 2020; 594:3409-3438. [PMID: 33064843 DOI: 10.1002/1873-3468.13958] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 09/28/2020] [Accepted: 10/05/2020] [Indexed: 01/08/2023]
Abstract
Malformations of cortical development (MCDs) are a group of severe brain malformations associated with intellectual disability and refractory childhood epilepsy. Human missense heterozygous mutations in the 9 α-tubulin and 10 β-tubulin isoforms forming the heterodimers that assemble into microtubules (MTs) were found to cause MCDs. However, how a single mutated residue in a given tubulin isoform can perturb the entire microtubule population in a neuronal cell remains a crucial question. Here, we examined 85 MCD-associated tubulin mutations occurring in TUBA1A, TUBB2, and TUBB3 and their location in a three-dimensional (3D) microtubule cylinder. Mutations hitting residues exposed on the outer microtubule surface are likely to alter microtubule association with partners, while alteration of intradimer contacts may impair dimer stability and straightness. Other types of mutations are predicted to alter interdimer and lateral contacts, which are responsible for microtubule cohesion, rigidity, and dynamics. MCD-associated tubulin mutations surprisingly fall into all categories, thus providing unexpected insights into how a single mutation may impair microtubule function and elicit dominant effects in neurons.
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22
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Dynamic and asymmetric fluctuations in the microtubule wall captured by high-resolution cryoelectron microscopy. Proc Natl Acad Sci U S A 2020; 117:16976-16984. [PMID: 32636254 DOI: 10.1073/pnas.2001546117] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Microtubules are tubular polymers with essential roles in numerous cellular activities. Structures of microtubules have been captured at increasing resolution by cryo-EM. However, dynamic properties of the microtubule are key to its function, and this behavior has proved difficult to characterize at a structural level due to limitations in existing structure determination methods. We developed a high-resolution cryo-EM refinement method that divides an imaged microtubule into its constituent protofilaments, enabling deviations from helicity and other sources of heterogeneity to be quantified and corrected for at the single-subunit level. We demonstrate that this method improves the resolution of microtubule 3D reconstructions and substantially reduces anisotropic blurring artifacts, compared with methods that utilize helical symmetry averaging. Moreover, we identified an unexpected, discrete behavior of the m-loop, which mediates lateral interactions between neighboring protofilaments and acts as a flexible hinge between them. The hinge angle adopts preferred values corresponding to distinct conformations of the m-loop that are incompatible with helical symmetry. These hinge angles fluctuate in a stochastic manner, and perfectly cylindrical microtubule conformations are thus energetically and entropically penalized. The hinge angle can diverge further from helical symmetry at the microtubule seam, generating a subpopulation of highly distorted microtubules. However, the seam-distorted subpopulation disappears in the presence of Taxol, a microtubule stabilizing agent. These observations provide clues into the structural origins of microtubule flexibility and dynamics and highlight the role of structural polymorphism in defining microtubule behavior.
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23
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Tubulin tails and their modifications regulate protein diffusion on microtubules. Proc Natl Acad Sci U S A 2020; 117:8876-8883. [PMID: 32245812 DOI: 10.1073/pnas.1914772117] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Microtubules (MTs) are essential components of the eukaryotic cytoskeleton that serve as "highways" for intracellular trafficking. In addition to the well-known active transport of cargo by motor proteins, many MT-binding proteins seem to adopt diffusional motility as a transportation mechanism. However, because of the limited spatial resolution of current experimental techniques, the detailed mechanism of protein diffusion has not been elucidated. In particular, the precise role of tubulin tails and tail modifications in the diffusion process is unclear. Here, using coarse-grained molecular dynamics simulations validated against atomistic simulations, we explore the molecular mechanism of protein diffusion along MTs. We found that electrostatic interactions play a central role in protein diffusion; the disordered tubulin tails enhance affinity but slow down diffusion, and diffusion occurs in discrete steps. While diffusion along wild-type MT is performed in steps of dimeric tubulin, the removal of the tails results in a step of monomeric tubulin. We found that the energy barrier for diffusion is larger when diffusion on MTs is mediated primarily by the MT tails rather than the MT body. In addition, globular proteins (EB1 and PRC1) diffuse more slowly than an intrinsically disordered protein (Tau) on MTs. Finally, we found that polyglutamylation and polyglycylation of tubulin tails lead to slower protein diffusion along MTs, although polyglycylation leads to faster diffusion across MT protofilaments. Taken together, our results explain experimentally observed data and shed light on the roles played by disordered tubulin tails and tail modifications in the molecular mechanism of protein diffusion along MTs.
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24
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Keya JJ, Kabir AMR, Kakugo A. Synchronous operation of biomolecular engines. Biophys Rev 2020; 12:401-409. [PMID: 32125657 PMCID: PMC7242543 DOI: 10.1007/s12551-020-00651-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2020] [Accepted: 02/16/2020] [Indexed: 12/12/2022] Open
Abstract
Biomolecular motor systems are the smallest natural machines with an ability to convert chemical energy into mechanical work with remarkably high efficiency. Such attractive features enabled biomolecular motors to become classic tools in soft matter research over the past decade. For designing suitably engineered biomimetic systems, the biomolecular motors can potentially be used as molecular engines that can transform energy and ensure great advantages for the construction of bio-nanodevices and molecular robots. From the optimization of their prolonged lifetime to coordinate them into highly complex and ordered structures, enormous efforts have been devoted to make them useful in the synthetic environment. Synchronous operation of the biomolecular engines is one of the key criteria to coordinate them into certain different patterns, which depends on the local interaction of biomolecular motors. Utilizing chemical and physical stimuli, synchronization of biomolecular motor systems has become possible, which allows them to coordinate into different higher ordered patterns with different modes of functionality. Recently, programmed synchronous operation of the biomolecular engines has also been demonstrated, using a smart biomaterial to build up swarms reminiscent of nature. Here, we review the recent progress in the synchronized operation of biomolecular motors in engineered systems to explicitly program their interaction and further their applications. Such developments in the coordination of biomolecular motors have opened a broad way to explore the construction of future autonomous molecular machines and robots based on synchronization of biomolecular engines.
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Affiliation(s)
- Jakia Jannat Keya
- Faculty of Science, Hokkaido University, Sapporo, Hokkaido, 060-0810, Japan
| | | | - Akira Kakugo
- Faculty of Science, Hokkaido University, Sapporo, Hokkaido, 060-0810, Japan.
- Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo, Hokkaido, 060-0810, Japan.
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25
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Ye X, Kim T, Geyer EA, Rice LM. Insights into allosteric control of microtubule dynamics from a buried β-tubulin mutation that causes faster growth and slower shrinkage. Protein Sci 2020; 29:1429-1439. [PMID: 32077153 DOI: 10.1002/pro.3842] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 02/14/2020] [Accepted: 02/17/2020] [Indexed: 01/27/2023]
Abstract
αβ-tubulin subunits cycle through a series of different conformations in the polymer lattice during microtubule growing and shrinking. How these allosteric responses to different tubulin:tubulin contacts contribute to microtubule dynamics, and whether the contributions are evolutionarily conserved, remains poorly understood. Here, we sought to determine whether the microtubule-stabilizing effects (slower shrinking) of the β:T238A mutation we previously observed using yeast αβ-tubulin would generalize to mammalian microtubules. Using recombinant human microtubules as a model, we found that the mutation caused slow microtubule shrinking, indicating that this effect of the mutation is indeed conserved. However, unlike in yeast, β:T238A human microtubules grew faster than wild-type and the mutation did not appear to attenuate the conformational change associated with guanosine 5'-triphosphate (GTP) hydrolysis in the lattice. We conclude that the assembly-dependent conformational change in αβ-tubulin can contribute to determine the rates of microtubule growing as well as shrinking. Our results also suggest that an allosteric perturbation like the β:T238A mutation can alter the behavior of terminal subunits without accompanying changes in the conformation of fully surrounded subunits in the body of the microtubule.
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Affiliation(s)
- Xuecheng Ye
- UT Southwestern Medical Center, Departments of Biophysics and Biochemistry, Dallas, Texas, USA
| | - Tae Kim
- UT Southwestern Medical Center, Departments of Biophysics and Biochemistry, Dallas, Texas, USA
| | - Elisabeth A Geyer
- UT Southwestern Medical Center, Departments of Biophysics and Biochemistry, Dallas, Texas, USA
| | - Luke M Rice
- UT Southwestern Medical Center, Departments of Biophysics and Biochemistry, Dallas, Texas, USA
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26
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Hornak I, Rieger H. Stochastic Model of T Cell Repolarization during Target Elimination I. Biophys J 2020; 118:1733-1748. [PMID: 32130873 DOI: 10.1016/j.bpj.2020.01.045] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 01/27/2020] [Accepted: 01/30/2020] [Indexed: 12/16/2022] Open
Abstract
Cytotoxic T lymphocytes (T) and natural killer cells are the main cytotoxic killer cells of the human body to eliminate pathogen-infected or tumorigenic cells (i.e., target cells). Once a natural killer or T cell has identified a target cell, they form a tight contact zone, the immunological synapse (IS). One then observes a repolarization of the cell involving the rotation of the microtubule (MT) cytoskeleton and a movement of the MT organizing center (MTOC) to a position that is just underneath the plasma membrane at the center of the IS. Concomitantly, a massive relocation of organelles attached to MTs is observed, including the Golgi apparatus, lytic granules, and mitochondria. Because the mechanism of this relocation is still elusive, we devise a theoretical model for the molecular-motor-driven motion of the MT cytoskeleton confined between plasma membrane and nucleus during T cell polarization. We analyze different scenarios currently discussed in the literature, the cortical sliding and capture-shrinkage mechanisms, and compare quantitative predictions about the spatiotemporal evolution of MTOC position and MT cytoskeleton morphology with experimental observations. The model predicts the experimentally observed biphasic nature of the repositioning due to an interplay between MT cytoskeleton geometry and motor forces and confirms the dominance of the capture-shrinkage over the cortical sliding mechanism when the MTOC and IS are initially diametrically opposed. We also find that the two mechanisms act synergistically, thereby reducing the resources necessary for repositioning. Moreover, it turns out that the localization of dyneins in the peripheral supramolecular activation cluster facilitates their interaction with the MTs. Our model also opens a way to infer details of the dynein distribution from the experimentally observed features of the MT cytoskeleton dynamics. In a subsequent publication, we will address the issue of general initial configurations and situations in which the T cell established two ISs.
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Affiliation(s)
- Ivan Hornak
- Center for Biophysics (ZBP) and Department of Theoretical Physics, Saarland University, Saarbrücken, Germany
| | - Heiko Rieger
- Center for Biophysics (ZBP) and Department of Theoretical Physics, Saarland University, Saarbrücken, Germany.
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27
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A microtubule RELION-based pipeline for cryo-EM image processing. J Struct Biol 2019; 209:107402. [PMID: 31610239 PMCID: PMC6961209 DOI: 10.1016/j.jsb.2019.10.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 10/04/2019] [Accepted: 10/07/2019] [Indexed: 12/20/2022]
Abstract
MiRP is a pipeline for processing cryo-EM images of microtubules in RELION. MiRP manages microtubule heterogeneity and pseudo-symmetry. MiRP reduces errors in angular and translational alignment. MiRP improved reconstructions from three different microtubule datasets.
Microtubules are polar filaments built from αβ-tubulin heterodimers that exhibit a range of architectures in vitro and in vivo. Tubulin heterodimers are arranged helically in the microtubule wall but many physiologically relevant architectures exhibit a break in helical symmetry known as the seam. Noisy 2D cryo-electron microscopy projection images of pseudo-helical microtubules therefore depict distinct but highly similar views owing to the high structural similarity of α- and β-tubulin. The determination of the αβ-tubulin register and seam location during image processing is essential for alignment accuracy that enables determination of biologically relevant structures. Here we present a pipeline designed for image processing and high-resolution reconstruction of cryo-electron microscopy microtubule datasets, based in the popular and user-friendly RELION image-processing package, Microtubule RELION-based Pipeline (MiRP). The pipeline uses a combination of supervised classification and prior knowledge about geometric lattice constraints in microtubules to accurately determine microtubule architecture and seam location. The presented method is fast and semi-automated, producing near-atomic resolution reconstructions with test datasets that contain a range of microtubule architectures and binding proteins.
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28
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Directional Stepping Model for Yeast Dynein: Longitudinal- and Side-Step Distributions. Biophys J 2019; 117:1892-1899. [PMID: 31676137 DOI: 10.1016/j.bpj.2019.09.043] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 09/08/2019] [Accepted: 09/30/2019] [Indexed: 12/19/2022] Open
Abstract
Motor proteins are biological machines that convert chemical energy stored in ATP to mechanical work. Kinesin and dynein are microtubule (MT)-associated motor proteins that, among other functions, facilitate intracellular transport. Here, we focus on dynein motility. We deduce the directional step distribution of yeast dynein motor protein on the MT surface by combing intrinsic features of the dynein and MTs. These include the probability distribution of the separation vector between the two microtubule-binding domains, the angular probability distribution of a single microtubule-binding domain translation, the existence of an MT seam defect, MT-binding sites, and theoretical extension that accounts for a load force on the motor. Our predictions are in excellent accord with the measured longitudinal step size distributions at various load forces. Moreover, we predict the side-step distribution and its dependence on longitudinal load forces, which shows a few surprising features. First, the distribution is broad. Second, in the absence of load, we find a small right-handed bias. Third, the side-step bias is susceptible to the longitudinal load force; it vanishes at a load equal to the motor stalling force and changes to a left-hand bias above that value. Fourth, our results are sensitive to the ability of the motor to explore the seam several times during its walk. Although available measurements of side-way distribution are limited, our findings are amenable to experimental check and, moreover, suggest a diversity of results depending on whether the MT seam is viable to motor sampling.
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29
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Affiliation(s)
- Gadiel Saper
- Department of Biomedical Engineering, Columbia University, New York, New York 10027, United States
| | - Henry Hess
- Department of Biomedical Engineering, Columbia University, New York, New York 10027, United States
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30
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C SK, Gadewal N, Choudhary RK, Dasgupta D. Insights into the flexibility of the T3 loop and GTPase activating protein (GAP) domain of dimeric α and β tubulins from a molecular dynamics perspective. Comput Biol Chem 2019; 82:37-43. [PMID: 31255973 DOI: 10.1016/j.compbiolchem.2019.06.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2017] [Revised: 03/09/2019] [Accepted: 06/12/2019] [Indexed: 10/26/2022]
Abstract
Tubulin protein is the fundamental unit of microtubules, and comprises of α and β subunits arranged in an alternate manner forming protofilaments. These longitudinal protofilaments are made up of intra- (α-β) and inter-dimer (β-α) interactions. Literature review confirms that GTP hydrolysis results in considerable structural rearrangement within GTP binding site of β-α dimer interface after the release of γ phosphate. In addition to this, the intra-dimer interface exhibits structural rigidity which needs further investigation. In this study, we explored the reasons for the flexibility and the rigidity of the β-α dimer and the α-β dimer respectively through molecular simulation and Anisotropic Normal Mode based analysis. As per the sequence alignment report, two glycine residues (Gly96 and Gly98) were observed in the T3 loop of the β subunit which get substituted by Asp98 and Ala100 in the T3 loop of the α subunit. The higher mobility of glycine residues contributes to the flexibility of the T3 loop of inter-dimer when they come in direct contact with the GTPase Activating Protein (GAP) domain of the subunit. This was confirmed through RMSD, RMSF and Radius of Gyration based studies. Conversely, the intra-dimer exhibited a lower mobility in the absence of glycine residues. As per ANM based analysis, positive domain correlations were observed between T3 loop and GAP domain of intra- and inter- dimeric contact regions. However, these correlation motions were higher in the intra-dimer as compared to the inter-dimer interface. Thus on the basis of our findings, we hypothesize that the higher flexibility of T3 loop and the GAP domain of the inter-dimer is required for structural rearrangement and protofilament stability during hydrolysis. Furthermore, the slightly rigid nature of the T3 loop and the GAP domain of the intra-dimer assists in enhancing the monomer-monomer interaction through the higher positive domain correlation.
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Affiliation(s)
- Selvaa Kumar C
- School of Biotechnology and Bioinformatics, D.Y. Patil Deemed to be University, CBD Belapur, Navi Mumbai, India.
| | - Nikhil Gadewal
- Advanced Centre for Treatment, Research and Education in Cancer (ACTREC), Kharghar, Navi Mumbai, India.
| | - Rajan Kumar Choudhary
- Advanced Centre for Treatment, Research and Education in Cancer (ACTREC), Kharghar, Navi Mumbai, India
| | - Debjani Dasgupta
- School of Biotechnology and Bioinformatics, D.Y. Patil Deemed to be University, CBD Belapur, Navi Mumbai, India
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31
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Abstract
We report a complete 3D structural model of typical epithelial primary cilia based on structural maps of full-length primary cilia obtained by serial section electron tomography. Our data demonstrate the architecture of primary cilia differs extensively from the commonly acknowledged 9+0 paradigm. The axoneme structure is relatively stable but gradually evolves from base to tip with a decreasing number of microtubule complexes (MtCs) and a reducing diameter. The axonemal MtCs are cross-linked by previously unrecognized fibrous protein networks. Such an architecture explains why primary cilia can elastically withstand liquid flow for mechanosensing. The nine axonemal MtCs in a cilium are found to differ significantly in length indicating intraflagellar transport processes in primary cilia may be more complicated than that reported for motile cilia. The 3D maps of microtubule doublet-singlet transitions generally display longitudinal gaps at the inner junction between the A- and B-tubules, which indicates the inner junction protein is a major player in doublet-singlet transitions. In addition, vesicles releasing from kidney primary cilia were observed in the structural maps, supporting that ciliary vesicles budding may serve as ectosomes for cell-cell communication.
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32
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Hebebrand M, Hüffmeier U, Trollmann R, Hehr U, Uebe S, Ekici AB, Kraus C, Krumbiegel M, Reis A, Thiel CT, Popp B. The mutational and phenotypic spectrum of TUBA1A-associated tubulinopathy. Orphanet J Rare Dis 2019; 14:38. [PMID: 30744660 PMCID: PMC6371496 DOI: 10.1186/s13023-019-1020-x] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 02/03/2019] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND The TUBA1A-associated tubulinopathy is clinically heterogeneous with brain malformations, microcephaly, developmental delay and epilepsy being the main clinical features. It is an autosomal dominant disorder mostly caused by de novo variants in TUBA1A. RESULTS In three individuals with developmental delay we identified heterozygous de novo missense variants in TUBA1A using exome sequencing. While the c.1307G > A, p.(Gly436Asp) variant was novel, the two variants c.518C > T, p.(Pro173Leu) and c.641G > A, p.(Arg214His) were previously described. We compared the variable phenotype observed in these individuals with a carefully conducted review of the current literature and identified 166 individuals, 146 born and 20 fetuses with a TUBA1A variant. In 107 cases with available clinical information we standardized the reported phenotypes according to the Human Phenotype Ontology. The most commonly reported features were developmental delay (98%), anomalies of the corpus callosum (96%), microcephaly (76%) and lissencephaly (agyria-pachygyria) (70%), although reporting was incomplete in the different studies. We identified a total of 121 specific variants, including 15 recurrent ones. Missense variants cluster in the C-terminal region around the most commonly affected amino acid position Arg402 (13.3%). In a three-dimensional protein model, 38.6% of all disease-causing variants including those in the C-terminal region are predicted to affect the binding of microtubule-associated proteins or motor proteins. Genotype-phenotype analysis for recurrent variants showed an overrepresentation of certain clinical features. However, individuals with these variants are often reported in the same publication. CONCLUSIONS With 166 individuals, we present the most comprehensive phenotypic and genotypic standardized synopsis for clinical interpretation of TUBA1A variants. Despite this considerable number, a detailed genotype-phenotype characterization is limited by large inter-study variability in reporting.
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Affiliation(s)
- Moritz Hebebrand
- Institute of Human Genetics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schwabachanlage 10, 91054, Erlangen, Germany
| | - Ulrike Hüffmeier
- Institute of Human Genetics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schwabachanlage 10, 91054, Erlangen, Germany
| | - Regina Trollmann
- Department of Pediatrics, Division of Neuropediatrics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Ute Hehr
- Institute of Human Genetics, University of Regensburg, Regensburg, Germany
| | - Steffen Uebe
- Institute of Human Genetics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schwabachanlage 10, 91054, Erlangen, Germany
| | - Arif B Ekici
- Institute of Human Genetics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schwabachanlage 10, 91054, Erlangen, Germany
| | - Cornelia Kraus
- Institute of Human Genetics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schwabachanlage 10, 91054, Erlangen, Germany
| | - Mandy Krumbiegel
- Institute of Human Genetics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schwabachanlage 10, 91054, Erlangen, Germany
| | - André Reis
- Institute of Human Genetics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schwabachanlage 10, 91054, Erlangen, Germany
| | - Christian T Thiel
- Institute of Human Genetics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schwabachanlage 10, 91054, Erlangen, Germany.
| | - Bernt Popp
- Institute of Human Genetics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schwabachanlage 10, 91054, Erlangen, Germany
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Chen H, Zhou K, Wang Y, Zang J, Zhao G. Self-assembly of engineered protein nanocages into reversible ordered 3D superlattices mediated by zinc ions. Chem Commun (Camb) 2019; 55:11299-11302. [DOI: 10.1039/c9cc06262a] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Zinc ion triggered self-assembly of re-engineered Dps nanocages into highly ordered architectures with a bcc structure.
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Affiliation(s)
- H. Chen
- Beijing Advanced Innovation Center for Food Nutrition and Human Health
- College of Food Science & Nutritional Engineering
- China Agricultural University
- Beijing Key Laboratory of Functional Food from Plant Resources
- Beijing
| | - K. Zhou
- Beijing Advanced Innovation Center for Food Nutrition and Human Health
- College of Food Science & Nutritional Engineering
- China Agricultural University
- Beijing Key Laboratory of Functional Food from Plant Resources
- Beijing
| | - Y. Wang
- Beijing Advanced Innovation Center for Food Nutrition and Human Health
- College of Food Science & Nutritional Engineering
- China Agricultural University
- Beijing Key Laboratory of Functional Food from Plant Resources
- Beijing
| | - J. Zang
- Beijing Advanced Innovation Center for Food Nutrition and Human Health
- College of Food Science & Nutritional Engineering
- China Agricultural University
- Beijing Key Laboratory of Functional Food from Plant Resources
- Beijing
| | - G. Zhao
- Beijing Advanced Innovation Center for Food Nutrition and Human Health
- College of Food Science & Nutritional Engineering
- China Agricultural University
- Beijing Key Laboratory of Functional Food from Plant Resources
- Beijing
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34
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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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35
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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: 86] [Impact Index Per Article: 14.3] [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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36
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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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37
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Abstract
Microtubules act as "railways" for motor-driven intracellular transport, interact with accessory proteins to assemble into larger structures such as the mitotic spindle, and provide an organizational framework to the rest of the cell. Key to these functions is the fact that microtubules are "dynamic." As with actin, the polymer dynamics are driven by nucleotide hydrolysis and influenced by a host of specialized regulatory proteins, including microtubule-associated proteins. However, microtubule turnover involves a surprising behavior-termed dynamic instability-in which individual polymers switch stochastically between growth and depolymerization. Dynamic instability allows microtubules to explore intracellular space and remodel in response to intracellular and extracellular cues. Here, we review how such instability is central to the assembly of many microtubule-based structures and to the robust functioning of the microtubule cytoskeleton.
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Affiliation(s)
- Holly V Goodson
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556
| | - Erin M Jonasson
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556
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38
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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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39
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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: 56] [Impact Index Per Article: 9.3] [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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40
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Shirmovsky SE, Shulga DV. Elastic, dipole-dipole interaction and viscosity impact on vibrational properties of anisotropic hexagonal microtubule lattice. Biosystems 2018. [PMID: 29526816 DOI: 10.1016/j.biosystems.2018.03.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The paper investigates microtubules lattice properties taking into consideration elastic, dipole-dipole interaction of tubulins and viscosity. A microtubule is modeled as a system of bound tubulins, forming a skewed hexagonal two-dimensional lattice. Wave frequencies and group velocities have been calculated. Calculations have been performed for various directions of wave front propagation: helix, along the protofilament, and anti-helix. Three different wave polarization directions have been considered. It has been shown that the direction of the wave polarization influences the frequency and wave group velocity values in the lattice considerably. The impact of dipole-dipole interaction greatly depends on the direction of the wave polarization; thus, it is only moderate for the longitudinally (LA) polarized waves while it is sufficient for the transversely (TA), and out-of-plane (ZA) polarized waves. Moreover dipole-dipole interaction may result in the waves which are able to cause the rupture of microtubules. With viscosity considered, lattice oscillations become harmonically damped only over a certain wavelength range when longitudinal polarization occurs. Out of this range as well as for the other polarization directions, lattice deviations from equilibrium are dampened exponentially. Taking viscosity into consideration also results in a noticeable decrease in frequency and increase in the group wave velocity when the waves are longitudinally polarized. Reverse wave domains which may be associated with a possible phenomenon of negative refraction have been determined for hexagonal microtubule lattice.
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Affiliation(s)
- S Eh Shirmovsky
- Theoretical and Nuclear Physics Chair, Far Eastern Federal University, 8 Sukhanov St., Vladivostok 690950, Russia.
| | - D V Shulga
- Theoretical and Nuclear Physics Chair, Far Eastern Federal University, 8 Sukhanov St., Vladivostok 690950, Russia.
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41
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Yang G, Wu L, Chen G, Jiang M. Precise protein assembly of array structures. Chem Commun (Camb) 2018; 52:10595-605. [PMID: 27384233 DOI: 10.1039/c6cc04190f] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The assembly of proteins into various nano-objects with regular and periodic microstructures, i.e. protein arrays, is a fast-growing field in materials science. Due to the structural complexity of proteins, reports in this field are still quite limited. In this review, we summarize the recent developments in protein array construction by different driving forces, including electrostatic interactions, metal-ligand interactions, molecular recognition and protein-protein interactions. In line with our particular interest, assemblies driven by molecular recognition are particularly explored. Finally, functionalities of the obtained protein arrays are briefly discussed.
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Affiliation(s)
- Guang Yang
- State Key Laboratory of Molecular Engineering of Polymers and Department of Macromolecular Science, Fudan University, Shanghai 200433, China.
| | - Libin Wu
- State Key Laboratory of Molecular Engineering of Polymers and Department of Macromolecular Science, Fudan University, Shanghai 200433, China.
| | - Guosong Chen
- State Key Laboratory of Molecular Engineering of Polymers and Department of Macromolecular Science, Fudan University, Shanghai 200433, China.
| | - Ming Jiang
- State Key Laboratory of Molecular Engineering of Polymers and Department of Macromolecular Science, Fudan University, Shanghai 200433, China.
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42
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Huang H, Yang T, Shao Q, Majumder T, Mell K, Liu G. Human TUBB3 Mutations Disrupt Netrin Attractive Signaling. Neuroscience 2018; 374:155-171. [PMID: 29382549 DOI: 10.1016/j.neuroscience.2018.01.046] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2017] [Revised: 01/16/2018] [Accepted: 01/21/2018] [Indexed: 02/07/2023]
Abstract
Heterozygous missense mutations in human TUBB3 gene result in a spectrum of brain malformations associated with defects in axon guidance, neuronal migration and differentiation. However, the molecular mechanisms underlying mutation-related axon guidance abnormalities are unclear. Recent studies have shown that netrin-1, a canonical guidance cue, induced the interaction of TUBB3 with the netrin receptor deleted in colorectal cancer (DCC). Furthermore, TUBB3 is required for netrin-1-induced axon outgrowth, branching and pathfinding. Here, we provide evidence that TUBB3 mutations impair netrin/DCC signaling in the developing nervous system. The interaction of DCC with most TUBB3 mutants (eight out of twelve) is significantly reduced compared to the wild-type TUBB3. TUBB3 mutants R262C and A302V exhibit decreased subcellular colocalization with DCC in the growth cones of primary neurons. Netrin-1 increases the interaction of endogenous DCC with wild-type human TUBB3, but not R262C or A302V, in primary neurons. Netrin-1 also increases co-sedimentation of DCC with polymerized microtubules (MTs) in primary neurons expressing the wild-type TUBB3, but not R262C or A302V. Expression of either R262C or A302V not only suppresses netrin-1-induced neurite outgrowth, branching and attraction in vitro, but also causes defects in spinal cord commissural axon (CA) projection and pathfinding in ovo. Our study reveals that missense TUBB3 mutations specifically disrupt netrin/DCC-mediated attractive signaling.
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Affiliation(s)
- Huai Huang
- Department of Biological Sciences, University of Toledo, 2801 West Bancroft St., Toledo, OH 43606, USA
| | - Tao Yang
- Department of Biological Sciences, University of Toledo, 2801 West Bancroft St., Toledo, OH 43606, USA
| | - Qiangqiang Shao
- Department of Biological Sciences, University of Toledo, 2801 West Bancroft St., Toledo, OH 43606, USA
| | - Tanushree Majumder
- Department of Biological Sciences, University of Toledo, 2801 West Bancroft St., Toledo, OH 43606, USA
| | - Kristopher Mell
- Department of Biological Sciences, University of Toledo, 2801 West Bancroft St., Toledo, OH 43606, USA
| | - Guofa Liu
- Department of Biological Sciences, University of Toledo, 2801 West Bancroft St., Toledo, OH 43606, USA.
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43
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Pouchucq L, Lobos-Ruiz P, Araya G, Valpuesta JM, Monasterio O. The chaperonin CCT promotes the formation of fibrillar aggregates of γ-tubulin. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2018; 1866:519-526. [PMID: 29339327 DOI: 10.1016/j.bbapap.2018.01.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Revised: 01/08/2018] [Accepted: 01/09/2018] [Indexed: 12/29/2022]
Abstract
The type II chaperonin CCT is involved in the prevention of the pathogenesis of numerous human misfolding disorders, as it sequesters misfolded proteins, blocks their aggregation and helps them to achieve their native state. In addition, it has been reported that CCT can prevent the toxicity of non-client amyloidogenic proteins by the induction of non-toxic aggregates, leading to new insight in chaperonin function as an aggregate remodeling factor. Here we add experimental evidence to this alternative mechanism by which CCT actively promotes the formation of conformationally different aggregates of γ-tubulin, a non-amyloidogenic CCT client protein, which are mediated by specific CCT-γ-tubulin interactions. The in vitro-induced aggregates were in some cases long fiber polymers, which compete with the amorphous aggregates. Direct injection of unfolded purified γ-tubulin into single-cell zebra fish embryos allowed us to relate this in vitro activity with the in vivo formation of intracellular aggregates. Injection of a CCT-binding deficient γ-tubulin mutant dramatically diminished the size of the intracellular aggregates, increasing the toxicity of the misfolded protein. These results point to CCT having a role in the remodeling of aggregates, constituting one of its many functions in cellular proteostasis.
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Affiliation(s)
- Luis Pouchucq
- Laboratorio de Biología Estructural y Molecular, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile; Laboratorio de Biotecnología Vegetal Ambiental, Departamento de Biotecnología, Universidad Tecnológica Metropolitana, Santiago, Chile
| | - Pablo Lobos-Ruiz
- Laboratorio de Biología Estructural y Molecular, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Gissela Araya
- Laboratorio de Biología Estructural y Molecular, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - José María Valpuesta
- Departamento de Estructura de Macromoléculas, Centro Nacional de Biotecnología (CNB-CSIC), Campus de la Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Octavio Monasterio
- Laboratorio de Biología Estructural y Molecular, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile.
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44
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Calcium-axonemal microtubuli interactions underlie mechanism(s) of primary cilia morphological changes. J Biol Phys 2017; 44:53-80. [PMID: 29090363 DOI: 10.1007/s10867-017-9475-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 10/04/2017] [Indexed: 12/16/2022] Open
Abstract
We have used cell culture of astrocytes aligned within microchannels to investigate calcium effects on primary cilia morphology. In the absence of calcium and in the presence of flow of media (10 μL.s-1) the majority (90%) of primary cilia showed reversible bending with an average curvature of 2.1 ± 0.9 × 10-4 nm-1. When 1.0 mM calcium was present, 90% of cilia underwent bending. Forty percent of these cilia demonstrated strong irreversible bending, resulting in a final average curvature of 3.9 ± 1 × 10-4 nm-1, while 50% of cilia underwent bending similar to that observed during calcium-free flow. The average length of cilia was shifted toward shorter values (3.67 ± 0.34 μm) when exposed to excess calcium (1.0 mM), compared to media devoid of calcium (3.96 ± 0.26 μm). The number of primary cilia that became curved after calcium application was reduced when the cell culture was pre-incubated with 15 μM of the microtubule stabilizer, taxol, for 60 min prior to calcium application. Calcium caused single microtubules to curve at a concentration ≈1.0 mM in vitro, but at higher concentration (≈1.5 mM) multiple microtubule curving occurred. Additionally, calcium causes microtubule-associated protein-2 conformational changes and its dislocation from the microtubule wall at the location of microtubule curvature. A very small amount of calcium, that is 1.45 × 1011 times lower than the maximal capacity of TRPPs calcium channels, may cause gross morphological changes (curving) of primary cilia, while global cytosol calcium levels are expected to remain unchanged. These findings reflect the non-linear manner in which primary cilia may respond to calcium signaling, which in turn may influence the course of development of ciliopathies and cancer.
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45
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Huzil JT, Chen K, Kurgan L, Tuszynski JA. The Roles of β-Tubulin Mutations and Isotype Expression in Acquired Drug Resistance. Cancer Inform 2017. [DOI: 10.1177/117693510700300028] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The antitumor drug paclitaxel stabilizes microtubules and reduces their dynamicity, promoting mitotic arrest and eventually apoptosis. Upon assembly of the α/β-tubulin heterodimer, GTP becomes bound to both the α and β-tubulin monomers. During microtubule assembly, the GTP bound to β-tubulin is hydrolyzed to GDP, eventually reaching steady-state equilibrium between free tubulin dimers and those polymerized into microtubules. Tubulin-binding drugs such as paclitaxel interact with β-tubulin, resulting in the disruption of this equilibrium. In spite of several crystal structures of tubulin, there is little biochemical insight into the mechanism by which anti-tubulin drugs target microtubules and alter their normal behavior. The mechanism of drug action is further complicated, as the description of altered β-tubulin isotype expression and/or mutations in tubulin genes may lead to drug resistance as has been described in the literature. Because of the relationship between β-tubulin isotype expression and mutations within β-tubulin, both leading to resistance, we examined the properties of altered residues within the taxane, colchicine and Vinca binding sites. The amount of data now available, allows us to investigate common patterns that lead to microtubule disruption and may provide a guide to the rational design of novel compounds that can inhibit microtubule dynamics for specific tubulin isotypes or, indeed resistant cell lines. Because of the vast amount of data published to date, we will only provide a broad overview of the mutational results and how these correlate with differences between tubulin isotypes. We also note that clinical studies describe a number of predictive factors for the response to anti-tubulin drugs and attempt to develop an understanding of the features within tubulin that may help explain how they may affect both microtubule assembly and stability.
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Affiliation(s)
- J. Torin Huzil
- Department of Oncology, University of Alberta, Edmonton, Alberta
| | - Ke Chen
- Department of Computer and Electrical Engineering, University of Alberta, Edmonton, Alberta, Canada
| | - Lukasz Kurgan
- Department of Computer and Electrical Engineering, University of Alberta, Edmonton, Alberta, Canada
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46
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Affiliation(s)
- Alexander F. Mason
- School of Chemistry, the Australian Centre for Nanomedicine and the ARC Centre of Excellence in Convergent Bio‐Nano Science and TechnologyThe University of New South WalesSydney Australia
| | - Pall Thordarson
- School of Chemistry, the Australian Centre for Nanomedicine and the ARC Centre of Excellence in Convergent Bio‐Nano Science and TechnologyThe University of New South WalesSydney Australia
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47
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Human histone deacetylase 6 shows strong preference for tubulin dimers over assembled microtubules. Sci Rep 2017; 7:11547. [PMID: 28912522 PMCID: PMC5599508 DOI: 10.1038/s41598-017-11739-3] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Accepted: 08/29/2017] [Indexed: 12/31/2022] Open
Abstract
Human histone deacetylase 6 (HDAC6) is the major deacetylase responsible for removing the acetyl group from Lys40 of α-tubulin (αK40), which is located lumenally in polymerized microtubules. Here, we provide a detailed kinetic analysis of tubulin deacetylation and HDAC6/microtubule interactions using individual purified components. Our data unequivocally show that free tubulin dimers represent the preferred HDAC6 substrate, with a K M value of 0.23 µM and a deacetylation rate over 1,500-fold higher than that of assembled microtubules. We attribute the lower deacetylation rate of microtubules to both longitudinal and lateral lattice interactions within tubulin polymers. Using TIRF microscopy, we directly visualized stochastic binding of HDAC6 to assembled microtubules without any detectable preferential binding to microtubule tips. Likewise, indirect immunofluorescence microscopy revealed that microtubule deacetylation by HDAC6 is carried out stochastically along the whole microtubule length, rather than from the open extremities. Our data thus complement prior studies on tubulin acetylation and further strengthen the rationale for the correlation between tubulin acetylation and microtubule age.
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48
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Santelices IB, Friesen DE, Bell C, Hough CM, Xiao J, Kalra A, Kar P, Freedman H, Rezania V, Lewis JD, Shankar K, Tuszynski JA. Response to Alternating Electric Fields of Tubulin Dimers and Microtubule Ensembles in Electrolytic Solutions. Sci Rep 2017; 7:9594. [PMID: 28851923 PMCID: PMC5574899 DOI: 10.1038/s41598-017-09323-w] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 07/20/2017] [Indexed: 12/17/2022] Open
Abstract
Microtubules (MTs), which are cylindrical protein filaments that play crucial roles in eukaryotic cell functions, have been implicated in electrical signalling as biological nanowires. We report on the small-signal AC (“alternating current”) conductance of electrolytic solutions containing MTs and tubulin dimers, using a microelectrode system. We find that MTs (212 nM tubulin) in a 20-fold diluted BRB80 electrolyte increase solution conductance by 23% at 100 kHz, and this effect is directly proportional to the concentration of MTs in solution. The frequency response of MT-containing electrolytes exhibits a concentration-independent peak in the conductance spectrum at 111 kHz (503 kHz FWHM that decreases linearly with MT concentration), which appears to be an intrinsic property of MT ensembles in aqueous environments. Conversely, tubulin dimers (42 nM) decrease solution conductance by 5% at 100 kHz under similar conditions. We attribute these effects primarily to changes in the mobility of ionic species due to counter-ion condensation effects, and changes in the solvent structure and solvation dynamics. These results provide insight into MTs’ ability to modulate the conductance of aqueous electrolytes, which in turn, has significant implications for biological information processing, especially in neurons, and for intracellular electrical communication in general.
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Affiliation(s)
- Iara B Santelices
- Department of Electrical & Computer Engineering, University of Alberta, Edmonton, Alberta, T6G 1H9, Canada.,Department of Oncology, University of Alberta, Edmonton, Alberta, T6G 1Z2, Canada
| | - Douglas E Friesen
- Department of Oncology, University of Alberta, Edmonton, Alberta, T6G 1Z2, Canada
| | - Clayton Bell
- Department of Oncology, University of Alberta, Edmonton, Alberta, T6G 1Z2, Canada
| | - Cameron M Hough
- Department of Oncology, University of Alberta, Edmonton, Alberta, T6G 1Z2, Canada.,Department of Medical Physics, Cross Cancer Institute, Edmonton, Alberta, T6G 1Z2, Canada
| | - Jack Xiao
- Department of Electrical & Computer Engineering, University of Alberta, Edmonton, Alberta, T6G 1H9, Canada.,Department of Oncology, University of Alberta, Edmonton, Alberta, T6G 1Z2, Canada
| | - Aarat Kalra
- Department of Electrical & Computer Engineering, University of Alberta, Edmonton, Alberta, T6G 1H9, Canada.,Department of Oncology, University of Alberta, Edmonton, Alberta, T6G 1Z2, Canada.,Department of Physics, University of Alberta, Edmonton, Alberta, T6G 2E1, Canada
| | - Piyush Kar
- Department of Electrical & Computer Engineering, University of Alberta, Edmonton, Alberta, T6G 1H9, Canada
| | - Holly Freedman
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta, T6G 2E1, Canada
| | - Vahid Rezania
- Department of Physical Sciences, MacEwan University, Edmonton, Alberta, T5J 4S2, Canada
| | - John D Lewis
- Department of Oncology, University of Alberta, Edmonton, Alberta, T6G 1Z2, Canada
| | - Karthik Shankar
- Department of Electrical & Computer Engineering, University of Alberta, Edmonton, Alberta, T6G 1H9, Canada. .,NRC National Institute for Nanotechnology, Edmonton, Alberta, T6G 2M9, Canada.
| | - Jack A Tuszynski
- Department of Oncology, University of Alberta, Edmonton, Alberta, T6G 1Z2, Canada. .,Department of Physics, University of Alberta, Edmonton, Alberta, T6G 2E1, Canada.
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49
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Yang CPH, Horwitz SB. Taxol ®: The First Microtubule Stabilizing Agent. Int J Mol Sci 2017; 18:ijms18081733. [PMID: 28792473 PMCID: PMC5578123 DOI: 10.3390/ijms18081733] [Citation(s) in RCA: 176] [Impact Index Per Article: 25.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 07/27/2017] [Accepted: 07/28/2017] [Indexed: 12/14/2022] Open
Abstract
Taxol®, an antitumor drug with significant activity, is the first microtubule stabilizing agent described in the literature. This short review of the mechanism of action of Taxol® emphasizes the research done in the Horwitz’ laboratory. It discusses the contribution of photoaffinity labeled analogues of Taxol® toward our understanding of the binding site of the drug on the microtubule. The importance of hydrogen/deuterium exchange experiments to further our insights into the stabilization of microtubules by Taxol® is addressed. The development of drug resistance, a major problem that arises in the clinic, is discussed. Studies describing differential drug binding to distinct β-tubulin isotypes are presented. Looking forward, it is suggested that the β-tubulin isotype content of a tumor may influence its responses to Taxol®.
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Affiliation(s)
- Chia-Ping Huang Yang
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
- Department of Obstetrics and Gynecology and Women's Health, Division of Gynecologic Oncology, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
| | - Susan Band Horwitz
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
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50
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Bell KM, Cha HK, Sindelar CV, Cochran JC. The yeast kinesin-5 Cin8 interacts with the microtubule in a noncanonical manner. J Biol Chem 2017; 292:14680-14694. [PMID: 28701465 PMCID: PMC5582858 DOI: 10.1074/jbc.m117.797662] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Revised: 06/28/2017] [Indexed: 11/06/2022] Open
Abstract
Kinesin motors play central roles in establishing and maintaining the mitotic spindle during cell division. Unlike most other kinesins, Cin8, a kinesin-5 motor in Saccharomyces cerevisiae, can move bidirectionally along microtubules, switching directionality according to biochemical conditions, a behavior that remains largely unexplained. To this end, we used biochemical rate and equilibrium constant measurements as well as cryo-electron microscopy methodologies to investigate the microtubule interactions of the Cin8 motor domain. These experiments unexpectedly revealed that, whereas Cin8 ATPase kinetics fell within measured ranges for kinesins (especially kinesin-5 proteins), approximately four motors can bind each αβ-tubulin dimer within the microtubule lattice. This result contrasted with those observations on other known kinesins, which can bind only a single "canonical" site per tubulin dimer. Competition assays with human kinesin-5 (Eg5) only partially abrogated this behavior, indicating that Cin8 binds microtubules not only at the canonical site, but also one or more separate ("noncanonical") sites. Moreover, we found that deleting the large, class-specific insert in the microtubule-binding loop 8 reverts Cin8 to one motor per αβ-tubulin in the microtubule. The novel microtubule-binding mode of Cin8 identified here provides a potential explanation for Cin8 clustering along microtubules and potentially may contribute to the mechanism for direction reversal.
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Affiliation(s)
- Kayla M Bell
- From the Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, Indiana 47405
| | - Hyo Keun Cha
- the Department of Cell Biology, Yale School of Medicine, and
| | - Charles V Sindelar
- the Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520
| | - Jared C Cochran
- From the Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, Indiana 47405,
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