1
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Song X, Li D, Gan L, Xiong X, Nie A, Zhao H, Hu Y, Li G, Guo J. Intravenous Injection of Na Ions Aggravates Ang II-Induced Hypertension-Related Vascular Endothelial Injury by Increasing Transmembrane Osmotic Pressure. Int J Nanomedicine 2023; 18:7505-7521. [PMID: 38106448 PMCID: PMC10723192 DOI: 10.2147/ijn.s435144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2023] [Accepted: 12/03/2023] [Indexed: 12/19/2023] Open
Abstract
Introduction Extracellular protein nanoparticles (PNs) and ions perform synergistical functions in the control of transmembrane osmotic pressure (OP) under isotonic conditions. Intravenous injection may disrupt the ion balance and alter PN levels in blood plasma, changing transmembrane OP and damaging vascular endothelial cells. Methods Na ions were injected into AngII-induced HUVECs to simulate cell injury in vitro, and tail vein infusion of Na ions into hypertensive rats was performed to assess vascular damage. Optical measurements using an intermediate filament (IF) tension probe were conducted to detect indicators related to transmembrane OP. Immunofluorescence, Western blotting and small interfering RNA (siRNA) transfection were employed to investigate inflammasomes and the relationship between Abl2 and inflammation. Results Electrolyte injections with sodium ions (but not glucose and hydroxyethyl starch) induced the production of ASC and NLRP3 inflammasomes in Ang II-induced HUVECs; this in turn resulted in the disorder of calcium signals, and changes in transmembrane OP and cell permeability. Moreover, injection of Na ions into Ang II-induced HUVECs activated the mechanosensitive protein Abl2, involved in inflammation-induced transmembrane OP changes. A drug combination was identified that could induce OP recovery and block hyperpermeability induced by cytoplasmic inflammatory corpuscles in vivo and in vitro. Conclusion Changes in extracellular PNs and ions following chemical stimuli (Ang II) participate in the regulation of transmembrane OP. Furthermore, injection of Na ions causes vascular endothelial injury in Ang II-induced cells in vitro and hypertension rats in vivo, suggesting it is not safe for hypertensive patients, and we propose a new drug combination as a solution.
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Affiliation(s)
- Xianrui Song
- Department of Biochemistry and Molecular Biology, School of Medicine & Holistic Integrative Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, 210023, People’s Republic of China
| | - Danyang Li
- Department of Biochemistry and Molecular Biology, School of Medicine & Holistic Integrative Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, 210023, People’s Republic of China
| | - Lingling Gan
- Experiment Center for Science and Technology, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, 210023, People’s Republic of China
| | - Xiyu Xiong
- Department of Biochemistry and Molecular Biology, School of Medicine & Holistic Integrative Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, 210023, People’s Republic of China
| | - Aobo Nie
- Department of Biochemistry and Molecular Biology, School of Medicine & Holistic Integrative Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, 210023, People’s Republic of China
| | - Huanhuan Zhao
- Basic Medical Experiment Center, School of Medicine & Holistic Integrative Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, 210023, People’s Republic of China
| | - Yunfeng Hu
- Department of Biochemistry and Molecular Biology, School of Medicine & Holistic Integrative Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, 210023, People’s Republic of China
| | - Guangming Li
- Department of Anesthesiology, Huaian First People’s Hospital, Nanjing Medical University, Huaian, Jiangsu, 223001, People’s Republic of China
| | - Jun Guo
- Department of Biochemistry and Molecular Biology, School of Medicine & Holistic Integrative Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, 210023, People’s Republic of China
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2
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Wu R, Guzman-Sepulveda J, Kalra A, Tuszynski J, Dogariu A. Thermal hysteresis in microtubule assembly/disassembly dynamics: The aging-induced degradation of tubulin dimers. Biochem Biophys Rep 2022; 29:101199. [PMID: 35036585 PMCID: PMC8749447 DOI: 10.1016/j.bbrep.2021.101199] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 12/29/2021] [Accepted: 12/31/2021] [Indexed: 11/08/2022] Open
Abstract
The assembly/disassembly of biological macromolecules plays an important role in their biological functionalities. Although the dynamics of tubulin polymers and their super-assembly into microtubule structures is critical for many cellular processes, details of their cyclical polymerization/depolymerization are not fully understood. Here, we use a specially designed light scattering technique to continuously examine the effects of temperature cycling on the process of microtubule assembly/disassembly. We observe a thermal hysteresis loop during tubulin assembly/disassembly, consistently with earlier reports on the coexistence of tubulin and microtubules as a phase transition. In a cyclical process, the structural hysteresis has a kinetic component that depends on the rate of temperature change but also an intrinsic thermodynamic component that depends on the protein topology, possibly related to irreversible processes. Analyzing the evolution of such thermal hysteresis loops over successive cycles, we found that the assembly/disassembly ceases after some time, which is indicative of protein aging leading to its inability to self-assemble after a finite number of temperature cycles. The emergence of assembly-incompetent tubulin could have major consequences for human pathologies related to microtubules, including aging, neurodegenerative diseases and cancer.
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Affiliation(s)
- R. Wu
- CREOL, College of Optics and Photonics, University of Central Florida, Orlando, FL, 32816, USA
| | - J.R. Guzman-Sepulveda
- CREOL, College of Optics and Photonics, University of Central Florida, Orlando, FL, 32816, USA
| | - A.P. Kalra
- Department of Physics, University of Alberta, 11335 Saskatchewan Dr NW, Edmonton, Alberta, T6G 2M9, Canada
| | - J.A. Tuszynski
- Department of Physics, University of Alberta, 11335 Saskatchewan Dr NW, Edmonton, Alberta, T6G 2M9, Canada
- DIMEAS, Polytechnic di Torino, Turin, I-10129, Italy
| | - A. Dogariu
- CREOL, College of Optics and Photonics, University of Central Florida, Orlando, FL, 32816, USA
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3
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Rice LM, Moritz M, Agard DA. Microtubules form by progressively faster tubulin accretion, not by nucleation-elongation. J Cell Biol 2021; 220:211894. [PMID: 33734292 PMCID: PMC7980253 DOI: 10.1083/jcb.202012079] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 02/12/2021] [Accepted: 02/17/2021] [Indexed: 01/14/2023] Open
Abstract
Microtubules are dynamic polymers that play fundamental roles in all eukaryotes. Despite their importance, how new microtubules form is poorly understood. Textbooks have focused on variations of a nucleation–elongation mechanism in which monomers rapidly equilibrate with an unstable oligomer (nucleus) that limits the rate of polymer formation; once formed, the polymer then elongates efficiently from this nucleus by monomer addition. Such models faithfully describe actin assembly, but they fail to account for how more complex polymers like hollow microtubules assemble. Here, we articulate a new model for microtubule formation that has three key features: (1) microtubules initiate via rectangular, sheet-like structures that grow faster the larger they become; (2) the dominant pathway proceeds via accretion, the stepwise addition of longitudinal or lateral layers; and (3) a “straightening penalty” to account for the energetic cost of tubulin’s curved-to-straight conformational transition. This model can quantitatively fit experimental assembly data, providing new insights into biochemical determinants and assembly pathways for microtubule nucleation.
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Affiliation(s)
- Luke M Rice
- Departments of Biophysics and Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX
| | - Michelle Moritz
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco CA
| | - David A Agard
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco CA
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4
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Best RL, LaPointe NE, Liang J, Ruan K, Shade MF, Wilson L, Feinstein SC. Tau isoform-specific stabilization of intermediate states during microtubule assembly and disassembly. J Biol Chem 2019; 294:12265-12280. [PMID: 31266806 DOI: 10.1074/jbc.ra119.009124] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 06/24/2019] [Indexed: 01/27/2023] Open
Abstract
The microtubule (MT)-associated protein tau regulates the critical growing and shortening behaviors of MTs, and its normal activity is essential for neuronal development and maintenance. Accordingly, aberrant tau action is tightly associated with Alzheimer's disease and is genetically linked to several additional neurodegenerative diseases known as tauopathies. Although tau is known to promote net MT growth and stability, the precise mechanistic details governing its regulation of MT dynamics remain unclear. Here, we have used the slowly-hydrolyzable GTP analog, guanylyl-(α,β)-methylene-diphosphonate (GMPCPP), to examine the structural effects of tau at MT ends that may otherwise be too transient to observe. The addition of both four-repeat (4R) and three-repeat (3R) tau isoforms to pre-formed GMPCPP MTs resulted in the formation of extended, multiprotofilament-wide projections at MT ends. Furthermore, at temperatures too low for assembly of bona fide MTs, both tau isoforms promoted the formation of long spiral ribbons from GMPCPP tubulin heterodimers. In addition, GMPCPP MTs undergoing cold-induced disassembly in the presence of 4R tau (and to a much lesser extent 3R tau) also formed spirals. Finally, three pathological tau mutations known to cause neurodegeneration and dementia were differentially compromised in their abilities to stabilize MT disassembly intermediates. Taken together, we propose that tau promotes the formation/stabilization of intermediate states in MT assembly and disassembly by promoting both longitudinal and lateral tubulin-tubulin contacts. We hypothesize that these activities represent fundamental aspects of tau action that normally occur at the GTP-rich ends of GTP/GDP MTs and that may be compromised in neurodegeneration-causing tau variants.
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Affiliation(s)
- Rebecca L Best
- Neuroscience Research Institute and Department of Molecular, Cellular, and Developmental Biology, University of California Santa Barbara, Santa Barbara, California 93106
| | - Nichole E LaPointe
- Neuroscience Research Institute and Department of Molecular, Cellular, and Developmental Biology, University of California Santa Barbara, Santa Barbara, California 93106
| | - Jiahao Liang
- Neuroscience Research Institute and Department of Molecular, Cellular, and Developmental Biology, University of California Santa Barbara, Santa Barbara, California 93106
| | - Kevin Ruan
- Neuroscience Research Institute and Department of Molecular, Cellular, and Developmental Biology, University of California Santa Barbara, Santa Barbara, California 93106
| | - Madeleine F Shade
- Neuroscience Research Institute and Department of Molecular, Cellular, and Developmental Biology, University of California Santa Barbara, Santa Barbara, California 93106
| | - Leslie Wilson
- Neuroscience Research Institute and Department of Molecular, Cellular, and Developmental Biology, University of California Santa Barbara, Santa Barbara, California 93106
| | - Stuart C Feinstein
- Neuroscience Research Institute and Department of Molecular, Cellular, and Developmental Biology, University of California Santa Barbara, Santa Barbara, California 93106.
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5
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Zhang J, Wang Y, Zheng Z, Sun X, Chen T, Li C, Zhang X, Guo J. Intracellular ion and protein nanoparticle-induced osmotic pressure modify astrocyte swelling and brain edema in response to glutamate stimuli. Redox Biol 2019; 21:101112. [PMID: 30685709 PMCID: PMC6351271 DOI: 10.1016/j.redox.2019.101112] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 01/02/2019] [Accepted: 01/14/2019] [Indexed: 12/28/2022] Open
Abstract
Intracellular tension activity plays a crucial role in cytotoxic brain edema and astrocyte swelling. Here, a few genetically encoded FRET-based tension probes were designed to detect cytoskeletal structural tension optically, including their magnitude and vectors. The astrocyte swelling resulted in GFAP tension increment, which is associated with the antagonistic effect of inward microfilaments (MFs) and microtubules (MTs) forces. In glutamate-induced astrocyte swelling, GFAP tension rise resulted from outward ion and protein nanoparticle-induced osmotic pressure (PN-OP) increases, where PN-OP could be elicited by MF and MT depolymerization, protein nanoparticle production, and activation of cofilin and stathmin-1. Attenuation of both ion osmotic pressure and PN-OP by drug combinations, together with free-radical scavenger, relieved cerebral edema in vivo. The study suggests that intracellular osmotic pressure (especially PN-OP) has a pivotal role in glutamate-induced astrocyte swelling and brain edema. Recovery of cytoplasmic potential is a promising target to develop new drugs and cure brain edema.
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Affiliation(s)
- JiaRui Zhang
- State Key Laboratory Cultivation Base For TCM Quality and Efficacy, School of Medicine and Life Science, Nanjing University of Chinese Medicine, Nanjing 210023, PR China; Key Laboratory of Drug Target and Drug for Degenerative Disease, Nanjing University of Chinese Medicine, Nanjing, PR China
| | - YuXuan Wang
- State Key Laboratory Cultivation Base For TCM Quality and Efficacy, School of Medicine and Life Science, Nanjing University of Chinese Medicine, Nanjing 210023, PR China; Key Laboratory of Drug Target and Drug for Degenerative Disease, Nanjing University of Chinese Medicine, Nanjing, PR China
| | - ZiHui Zheng
- State Key Laboratory Cultivation Base For TCM Quality and Efficacy, School of Medicine and Life Science, Nanjing University of Chinese Medicine, Nanjing 210023, PR China; Key Laboratory of Drug Target and Drug for Degenerative Disease, Nanjing University of Chinese Medicine, Nanjing, PR China
| | - XiaoHe Sun
- State Key Laboratory Cultivation Base For TCM Quality and Efficacy, School of Medicine and Life Science, Nanjing University of Chinese Medicine, Nanjing 210023, PR China; Key Laboratory of Drug Target and Drug for Degenerative Disease, Nanjing University of Chinese Medicine, Nanjing, PR China
| | - TingTing Chen
- State Key Laboratory Cultivation Base For TCM Quality and Efficacy, School of Medicine and Life Science, Nanjing University of Chinese Medicine, Nanjing 210023, PR China; Key Laboratory of Drug Target and Drug for Degenerative Disease, Nanjing University of Chinese Medicine, Nanjing, PR China
| | - Chen Li
- State Key Laboratory Cultivation Base For TCM Quality and Efficacy, School of Medicine and Life Science, Nanjing University of Chinese Medicine, Nanjing 210023, PR China; Key Laboratory of Drug Target and Drug for Degenerative Disease, Nanjing University of Chinese Medicine, Nanjing, PR China
| | - XiaoLong Zhang
- State Key Laboratory Cultivation Base For TCM Quality and Efficacy, School of Medicine and Life Science, Nanjing University of Chinese Medicine, Nanjing 210023, PR China; Key Laboratory of Drug Target and Drug for Degenerative Disease, Nanjing University of Chinese Medicine, Nanjing, PR China
| | - Jun Guo
- State Key Laboratory Cultivation Base For TCM Quality and Efficacy, School of Medicine and Life Science, Nanjing University of Chinese Medicine, Nanjing 210023, PR China; Key Laboratory of Drug Target and Drug for Degenerative Disease, Nanjing University of Chinese Medicine, Nanjing, PR China; Jiangsu Key Laboratory of Pediatric Respiratory Disease, Institute of Pediatrics, Nanjing University of Chinese Medicine, Nanjing, PR China.
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6
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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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7
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Thawani A, Kadzik RS, Petry S. XMAP215 is a microtubule nucleation factor that functions synergistically with the γ-tubulin ring complex. Nat Cell Biol 2018; 20:575-585. [PMID: 29695792 PMCID: PMC5926803 DOI: 10.1038/s41556-018-0091-6] [Citation(s) in RCA: 99] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 03/20/2018] [Indexed: 12/16/2022]
Abstract
How microtubules (MTs) are generated in the cell is a major question in understanding how the cytoskeleton is assembled. For several decades, γ-tubulin has been accepted as the universal MT nucleator of the cell. Although there is evidence that γ-tubulin complexes are not the sole MT nucleators, identification of other nucleation factors has proven difficult. Here, we report that the well-characterized MT polymerase XMAP215 (chTOG/Msps/Stu2p/Alp14/Dis1 homologue) is essential for MT nucleation in Xenopus egg extracts. The concentration of XMAP215 determines the extent of MT nucleation. Even though XMAP215 and the γ-tubulin ring complex (γ-TuRC) possess minimal nucleation activity individually, together, these factors synergistically stimulate MT nucleation in vitro. The amino-terminal TOG domains 1-5 of XMAP215 bind to αβ-tubulin and promote MT polymerization, whereas the conserved carboxy terminus is required for efficient MT nucleation and directly binds to γ-tubulin. In summary, XMAP215 and γ-TuRC together function as the principal nucleation module that generates MTs in cells.
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Affiliation(s)
- Akanksha Thawani
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA
| | - Rachel S Kadzik
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Sabine Petry
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA.
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8
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Vall-Sagarra A, McMicken B, Nonell S, Brancaleon L. Effects of Visible-Light Irradiation of Protoporphyrin IX on the Self-Assembly of Tubulin Heterodimers. Chemphyschem 2016; 17:3269-3282. [PMID: 27490308 PMCID: PMC5177992 DOI: 10.1002/cphc.201600629] [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: 06/13/2016] [Indexed: 11/10/2022]
Abstract
The formation and the effects of laser irradiation of the complex formed by protoporphyrin IX (PPIX) and tubulin was investigated. We have used tubulin as a model protein to investigate whether docked photoactive ligands can affect the structure and function of polypeptides upon exposure to visible light. We observed that laser irradiation in the Soret band prompts bleaching of the PPIX, which is accompanied by a sharp decrease in the intensity and average fluorescence lifetime of the protein (dominated by the four tryptophan residues of the tubulin monomer). The kinetics indicate non-trivial effects and suggest that the photosensitization of the PPIX bound to tubulin prompts structural alterations of the protein. These modifications were also observed through changes in the energy transfer between Trp residues and PPIX. The results suggest that laser irradiation produces localized partial unfolding of tubulin and that the changes prompt modification of the formation of microtubules in vitro. Measurements of singlet oxygen formation were inconclusive in determining whether the changes are prompted by reactive oxygen species or other excited state mechanisms.
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Affiliation(s)
- Alicia Vall-Sagarra
- Institut Quimic de Sarria, Universitat Ramon Llull, Via Augusta 390, 08017, Barcelona, Spain
- Department of Physics and Astronomy, University of Texas at San Antonio, San Antonio, TX, USA
| | - Brady McMicken
- Department of Physics and Astronomy, University of Texas at San Antonio, San Antonio, TX, USA
| | - Santi Nonell
- Institut Quimic de Sarria, Universitat Ramon Llull, Via Augusta 390, 08017, Barcelona, Spain
| | - Lorenzo Brancaleon
- Department of Physics and Astronomy, University of Texas at San Antonio, San Antonio, TX, USA.
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9
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Krieg E, Bastings MMC, Besenius P, Rybtchinski B. Supramolecular Polymers in Aqueous Media. Chem Rev 2016; 116:2414-77. [DOI: 10.1021/acs.chemrev.5b00369] [Citation(s) in RCA: 527] [Impact Index Per Article: 65.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
| | | | - Pol Besenius
- Institute
of Organic Chemistry, Johannes Gutenberg-Universität Mainz, Mainz 55128, Germany
| | - Boris Rybtchinski
- Department
of Organic Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel
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10
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Zhu C, Zuo Y, Liang B, Yue H, Yue X, Wen G, Wang R, Quan J, Du J, Bu X. Distinct tubulin dynamics in cancer cells explored using a highly tubulin-specific fluorescent probe. Chem Commun (Camb) 2015. [PMID: 26214302 DOI: 10.1039/c5cc04927j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
A highly specific fluorescent probe (OC9) was discovered exhibiting tubulin-specific affinity fluorescence, which allowed selective labeling of cellular tubulin in microtubules. Moreover, distinct tubulin dynamics in various cellular bio-settings such as drug resistant or epithelial-mesenchymal transition (EMT) cancer cells were directly observed for the first time via OC9 staining.
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Affiliation(s)
- Cuige Zhu
- School of Pharmaceutical Sciences, Sun Yat-sen University, GuangZhou 510006, China.
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11
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dos Santos RN, Morcos F, Jana B, Andricopulo AD, Onuchic JN. Dimeric interactions and complex formation using direct coevolutionary couplings. Sci Rep 2015; 5:13652. [PMID: 26338201 PMCID: PMC4559900 DOI: 10.1038/srep13652] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Accepted: 07/13/2015] [Indexed: 11/09/2022] Open
Abstract
We develop a procedure to characterize the association of protein structures into homodimers using coevolutionary couplings extracted from Direct Coupling Analysis (DCA) in combination with Structure Based Models (SBM). Identification of dimerization contacts using DCA is more challenging than intradomain contacts since direct couplings are mixed with monomeric contacts. Therefore a systematic way to extract dimerization signals has been elusive. We provide evidence that the prediction of homodimeric complexes is possible with high accuracy for all the cases we studied which have rich sequence information. For the most accurate conformations of the structurally diverse dimeric complexes studied the mean and interfacial RMSDs are 1.95Å and 1.44Å, respectively. This methodology is also able to identify distinct dimerization conformations as for the case of the family of response regulators, which dimerize upon activation. The identification of dimeric complexes can provide interesting molecular insights in the construction of large oligomeric complexes and be useful in the study of aggregation related diseases like Alzheimer's or Parkinson's.
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Affiliation(s)
- Ricardo N. dos Santos
- Center for Theoretical Biological Physics, Rice University, Houston, TX 77005-1827
- Laboratório de Química Medicinal e Computacional, Instituto de Física de São Carlos, Universidade de São Paulo, São Paulo, São Carlos, 13563-120, Brazil
| | - Faruck Morcos
- Center for Theoretical Biological Physics, Rice University, Houston, TX 77005-1827
| | - Biman Jana
- Department of Physical Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata-700032, India
| | - Adriano D. Andricopulo
- Laboratório de Química Medicinal e Computacional, Instituto de Física de São Carlos, Universidade de São Paulo, São Paulo, São Carlos, 13563-120, Brazil
| | - José N. Onuchic
- Center for Theoretical Biological Physics, Rice University, Houston, TX 77005-1827
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12
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Woodruff JB, Drubin DG, Barnes G. Spindle assembly requires complete disassembly of spindle remnants from the previous cell cycle. Mol Biol Cell 2011; 23:258-67. [PMID: 22090343 PMCID: PMC3258171 DOI: 10.1091/mbc.e11-08-0701] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Incomplete spindle disassembly causes lethality in budding yeast. We propose that spindle disassembly is required to reinitiate the spindle cycle during the subsequent mitosis by regenerating the nuclear pool of assembly-competent tubulin. Incomplete mitotic spindle disassembly causes lethality in budding yeast. To determine why spindle disassembly is required for cell viability, we used live-cell microscopy to analyze a double mutant strain containing a conditional mutant and a deletion mutant compromised for the kinesin-8 and anaphase-promoting complex-driven spindle-disassembly pathways (td-kip3 and doc1Δ, respectively). Under nonpermissive conditions, spindles in td-kip3 doc1Δ cells could break apart but could not disassemble completely. These cells could exit mitosis and undergo cell division. However, the daughter cells could not assemble functional, bipolar spindles in the ensuing mitosis. During the formation of these dysfunctional spindles, centrosome duplication and separation, as well as recruitment of key midzone-stabilizing proteins all appeared normal, but microtubule polymerization was nevertheless impaired and these spindles often collapsed. Introduction of free tubulin through episomal expression of α- and β-tubulin or introduction of a brief pulse of the microtubule-depolymerizing drug nocodazole allowed spindle assembly in these td-kip3 doc1Δ mutants. Therefore we propose that spindle disassembly is essential for regeneration of the intracellular pool of assembly-competent tubulin required for efficient spindle assembly during subsequent mitoses of daughter cells.
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Affiliation(s)
- Jeffrey B Woodruff
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
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13
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Smal I, Grigoriev I, Akhmanova A, Niessen WJ, Meijering E. Microtubule dynamics analysis using kymographs and variable-rate particle filters. IEEE TRANSACTIONS ON IMAGE PROCESSING : A PUBLICATION OF THE IEEE SIGNAL PROCESSING SOCIETY 2010; 19:1861-76. [PMID: 20227980 DOI: 10.1109/tip.2010.2045031] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Studying intracellular dynamics is of fundamental importance for understanding healthy life at the molecular level and for developing drugs to target disease processes. One of the key technologies to enable this research is the automated tracking and motion analysis of these objects in microscopy image sequences. To make better use of the spatiotemporal information than common frame-by-frame tracking methods, two alternative approaches have recently been proposed, based upon either Bayesian estimation or space-time segmentation. In this paper, we propose to combine the power of both approaches, and develop a new probabilistic method to segment the traces of the moving objects in kymograph representations of the image data. It is based on variable-rate particle filtering and uses multiscale trend analysis of the extracted traces to estimate the relevant kinematic parameters. Experiments on realistic synthetically generated images as well as on real biological image data demonstrate the improved potential of the new method for the analysis of microtubule dynamics in vitro.
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Affiliation(s)
- Ihor Smal
- Biomedical Imaging Group Rotterdam, Department of Medical Informatics, Erasmus MC, Rotterdam, The Netherlands.
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14
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Mechulam A, Chernov KG, Mucher E, Hamon L, Curmi PA, Pastré D. Polyamine sharing between tubulin dimers favours microtubule nucleation and elongation via facilitated diffusion. PLoS Comput Biol 2009; 5:e1000255. [PMID: 19119409 PMCID: PMC2599886 DOI: 10.1371/journal.pcbi.1000255] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2008] [Accepted: 11/17/2008] [Indexed: 12/18/2022] Open
Abstract
We suggest for the first time that the action of multivalent cations on microtubule dynamics can result from facilitated diffusion of GTP-tubulin to the microtubule ends. Facilitated diffusion can promote microtubule assembly, because, upon encountering a growing nucleus or the microtubule wall, random GTP-tubulin sliding on their surfaces will increase the probability of association to the target sites (nucleation sites or MT ends). This is an original explanation for understanding the apparent discrepancy between the high rate of microtubule elongation and the low rate of tubulin association at the microtubule ends in the viscous cytoplasm. The mechanism of facilitated diffusion requires an attraction force between two tubulins, which can result from the sharing of multivalent counterions. Natural polyamines (putrescine, spermidine, and spermine) are present in all living cells and are potent agents to trigger tubulin self-attraction. By using an analytical model, we analyze the implication of facilitated diffusion mediated by polyamines on nucleation and elongation of microtubules. In vitro experiments using pure tubulin indicate that the promotion of microtubule assembly by polyamines is typical of facilitated diffusion. The results presented here show that polyamines can be of particular importance for the regulation of the microtubule network in vivo and provide the basis for further investigations into the effects of facilitated diffusion on cytoskeleton dynamics.
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Affiliation(s)
- Alain Mechulam
- Laboratoire Structure-Activité des Biomolécules
Normales et Pathologiques, Université Evry-Val d'Essonne,
Evry, France
- INSERM, U829, Evry, France
| | - Konstantin G. Chernov
- Laboratoire Structure-Activité des Biomolécules
Normales et Pathologiques, Université Evry-Val d'Essonne,
Evry, France
- INSERM, U829, Evry, France
- Institute of Protein Research, Russian Academy of Sciences, Pushchino,
Moscow Region, Russia
| | - Elodie Mucher
- Laboratoire Structure-Activité des Biomolécules
Normales et Pathologiques, Université Evry-Val d'Essonne,
Evry, France
- INSERM, U829, Evry, France
| | - Loic Hamon
- Laboratoire Structure-Activité des Biomolécules
Normales et Pathologiques, Université Evry-Val d'Essonne,
Evry, France
- INSERM, U829, Evry, France
| | - Patrick A. Curmi
- Laboratoire Structure-Activité des Biomolécules
Normales et Pathologiques, Université Evry-Val d'Essonne,
Evry, France
- INSERM, U829, Evry, France
| | - David Pastré
- Laboratoire Structure-Activité des Biomolécules
Normales et Pathologiques, Université Evry-Val d'Essonne,
Evry, France
- INSERM, U829, Evry, France
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15
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White DE, Moggridge GD, Ian Wilson D. Solid–liquid transitions in the rheology of a structured yeast extract paste, Marmite™. J FOOD ENG 2008. [DOI: 10.1016/j.jfoodeng.2008.02.022] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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16
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Lee J, Gravel M, Zhang R, Thibault P, Braun PE. Process outgrowth in oligodendrocytes is mediated by CNP, a novel microtubule assembly myelin protein. ACTA ACUST UNITED AC 2007; 170:661-73. [PMID: 16103231 PMCID: PMC2171497 DOI: 10.1083/jcb.200411047] [Citation(s) in RCA: 131] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Oligodendrocytes (OLs) extend arborized processes that are supported by microtubules (MTs) and microfilaments. Little is known about proteins that modulate and interact with the cytoskeleton during myelination. Several lines of evidence suggest a role for 2′,3′-cyclic nucleotide 3′-phosphodiesterase (CNP) in mediating process formation in OLs. In this study, we report that tubulin is a major CNP-interacting protein. In vitro, CNP binds preferentially to tubulin heterodimers compared with MTs and induces MT assembly by copolymerizing with tubulin. CNP overexpression induces dramatic morphology changes in both glial and nonglial cells, resulting in MT and F-actin reorganization and formation of branched processes. These morphological effects are attributed to CNP MT assembly activity; branched process formation is either substantially reduced or abolished with the expression of loss-of-function mutants. Accordingly, cultured OLs from CNP-deficient mice extend smaller outgrowths with less arborized processes. We propose that CNP is an important component of the cytoskeletal machinery that directs process outgrowth in OLs.
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Affiliation(s)
- John Lee
- Department of Biochemistry, McGill University, Montreal, Quebec, Canada.
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17
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Schneider G, Nieznanski K, Kilanczyk E, Bieganowski P, Kuznicki J, Filipek A. CacyBP/SIP interacts with tubulin in neuroblastoma NB2a cells and induces formation of globular tubulin assemblies. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2007; 1773:1628-36. [PMID: 17916393 DOI: 10.1016/j.bbamcr.2007.07.013] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2007] [Revised: 07/18/2007] [Accepted: 07/24/2007] [Indexed: 01/13/2023]
Abstract
CacyBP/SIP, originally identified as a S100A6 (calcyclin) target, was later shown to interact with some other members of the S100 family as well as with Siah-1 and Skp1 proteins. Recently, it has been shown that CacyBP/SIP is up-regulated during differentiation of cardiomyocytes. In this work we show that the level of CacyBP/SIP is higher in differentiated neuroblastoma NB2a cells than in undifferentiated ones and that in cells overexpressing CacyBP/SIP the level of GAP-43, a marker of differentiation, was increased. Since the process of differentiation is accompanied by an extensive rearrangement of microtubules, we examined whether CacyBP/SIP interacted with tubulin. By applying cross-linking experiments we found that these two proteins bind directly. The dissociation constant of the tubulin-CacyBP/SIP complex determined by the surface plasmon resonance technique is 1.57 x 10(-7 )M which suggests that the interaction is tight. The interaction and co-localization of CacyBP/SIP and tubulin was also demonstrated by co-immunoprecipitation, affinity chromatography and immunofluorescence methods. Light scattering measurements and electron microscopy studies revealed that CacyBP/SIP, but not its homologue, Sgt1, increased tubulin oligomerization. Altogether, our results suggest that CacyBP/SIP, via its interaction with tubulin, might contribute to the differentiation of neuroblastoma NB2a cells.
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Affiliation(s)
- Gabriela Schneider
- Nencki Institute of Experimental Biology, 3 Pasteur Street, 02-093 Warsaw, Poland
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18
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Bonfils C, Bec N, Lacroix B, Harricane MC, Larroque C. Kinetic analysis of tubulin assembly in the presence of the microtubule-associated protein TOGp. J Biol Chem 2006; 282:5570-81. [PMID: 17178729 PMCID: PMC2238798 DOI: 10.1074/jbc.m605641200] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The microtubule-associated protein TOGp, which belongs to a widely distributed protein family from yeasts to humans, is highly expressed in human tumors and brain tissue. From purified components we have determined the effect of TOGp on thermally induced tubulin association in vitro in the presence of 1 mm GTP and 3.4 m glycerol. Physicochemical parameters describing the mechanism of tubulin polymerization were deduced from the kinetic curves by application of the classical theoretical models of tubulin assembly. We have calculated from the polymerization time curves a range of parameters characteristic of nucleation, elongation, or steady state phase. In addition, the tubulin subunits turnover at microtubule ends was deduced from tubulin GTPase activity. For comparison, parallel experiments were conducted with colchicine and taxol, two drugs active on microtubules and with tau, a structural microtubule-associated protein from brain tissue. TOGp, which decreases the nucleus size and the tenth time of the reaction (the time required to produce 10% of the final amount of polymer), shortens the nucleation phase of microtubule assembly. In addition, TOGp favors microtubule formation by increasing the apparent first order rate constant of elongation. Moreover, TOGp increases the total amount of polymer by decreasing the tubulin critical concentration and by inhibiting depolymerization during the steady state of the reaction.
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Affiliation(s)
- Claude Bonfils
- INSERM, EMI 229, CRLC Val d'Aurelle, 34298 Montpellier, France.
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19
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Fourest-Lieuvin A, Peris L, Gache V, Garcia-Saez I, Juillan-Binard C, Lantez V, Job D. Microtubule regulation in mitosis: tubulin phosphorylation by the cyclin-dependent kinase Cdk1. Mol Biol Cell 2005; 17:1041-50. [PMID: 16371510 PMCID: PMC1382296 DOI: 10.1091/mbc.e05-07-0621] [Citation(s) in RCA: 131] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The activation of the cyclin-dependent kinase Cdk1 at the transition from interphase to mitosis induces important changes in microtubule dynamics. Cdk1 phosphorylates a number of microtubule- or tubulin-binding proteins but, hitherto, tubulin itself has not been detected as a Cdk1 substrate. Here we show that Cdk1 phosphorylates beta-tubulin both in vitro and in vivo. Phosphorylation occurs on Ser172 of beta-tubulin, a site that is well conserved in evolution. Using a phosphopeptide antibody, we find that a fraction of the cell tubulin is phosphorylated during mitosis, and this tubulin phosphorylation is inhibited by the Cdk1 inhibitor roscovitine. In mitotic cells, phosphorylated tubulin is excluded from microtubules, being present in the soluble tubulin fraction. Consistent with this distribution in cells, the incorporation of Cdk1-phosphorylated tubulin into growing microtubules is impaired in vitro. Additionally, EGFP-beta3-tubulin(S172D/E) mutants that mimic phosphorylated tubulin are unable to incorporate into microtubules when expressed in cells. Modeling shows that the presence of a phosphoserine at position 172 may impair both GTP binding to beta-tubulin and interactions between tubulin dimers. These data indicate that phosphorylation of tubulin by Cdk1 could be involved in the regulation of microtubule dynamics during mitosis.
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Affiliation(s)
- Anne Fourest-Lieuvin
- Laboratoire du Cytosquelette, INSERM Unité 366, CEA, 38054 Grenoble Cedex 9, France.
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20
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Dhonukshe P, Mathur J, Hülskamp M, Gadella TWJ. Microtubule plus-ends reveal essential links between intracellular polarization and localized modulation of endocytosis during division-plane establishment in plant cells. BMC Biol 2005; 3:11. [PMID: 15831100 PMCID: PMC1087477 DOI: 10.1186/1741-7007-3-11] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2005] [Accepted: 04/14/2005] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND A key event in plant morphogenesis is the establishment of a division plane. A plant-specific microtubular preprophase band (PPB) accurately predicts the line of cell division, whereas the phragmoplast, another plant-specific array, executes cell division by maintaining this predicted line. Although establishment of these specific arrays apparently involves intracellular repolarization events that focus cellular resources to a division site, it still remains unclear how microtubules position the cell division planes. Here we study GFP-AtEB1 decorated microtubule plus-ends to dissect events at the division plane. RESULTS Early mitotic events included guided growth of endoplasmic microtubules (EMTs) towards the PPB site and their coincident localization with endocytic vesicles. Consequently, an endosomal belt lay in close proximity to the microtubular PPB at its maturation and was maintained during spindle formation. During cytokinesis, EMTs radiated from the former spindle poles in a geometrical conformation correlating with cell-plate navigation and tilt-correction. Naphthylphtalamic acid (NPA), an inhibitor of polar auxin efflux, caused abnormal PPBs and shifted division planes. CONCLUSION Our observations reveal a spatio-temporal link between microtubules and intracellular polarization essential for localized endocytosis and precise establishment of the division plane in plants. Additionally, they implicate the growth regulator, auxin, in this important cellular event.
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Affiliation(s)
- Pankaj Dhonukshe
- Section of Molecular Cytology, Swammerdam Institute for Life Sciences, University of Amsterdam, Kruislaan 316, 1098 SM Amsterdam, The Netherlands
- Centre for Molecular Biology of Plants, University of Tübingen, Auf der Morgenstelle 3, 72076 Tübingen, Germany
| | - Jaideep Mathur
- Department of Plant Agriculture, Molecular Cell Biology Laboratory, University of Guelph, Guelph, ON, N1G 2W1, Canada
| | - Martin Hülskamp
- Botanical Institute III, University of Köln, Gyrhofstrasse 15, Köln, 50931, Germany
| | - Theodorus WJ Gadella
- Section of Molecular Cytology, Swammerdam Institute for Life Sciences, University of Amsterdam, Kruislaan 316, 1098 SM Amsterdam, The Netherlands
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Arnal I, Heichette C, Diamantopoulos GS, Chrétien D. CLIP-170/tubulin-curved oligomers coassemble at microtubule ends and promote rescues. Curr Biol 2005; 14:2086-95. [PMID: 15589150 DOI: 10.1016/j.cub.2004.11.055] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2004] [Revised: 10/14/2004] [Accepted: 10/15/2004] [Indexed: 12/01/2022]
Abstract
BACKGROUND CLIP-170 is a microtubule binding protein specifically located at microtubule plus ends, where it modulates their dynamic properties and their interactions with intracellular organelles. The mechanism by which CLIP-170 is targeted to microtubule ends remains unclear today, as well as its precise effect on microtubule dynamics. RESULTS We used the N-terminal part of CLIP-170 (named H2), which contains the microtubule binding domains, to investigate how it modulates in vitro microtubule dynamics and structure. We found that H2 primarily promoted rescues (transitions from shrinkage to growth) of microtubules nucleated from pure tubulin and isolated centrosomes, and stimulated microtubule nucleation. Electron cryomicroscopy revealed that H2 induced the formation of tubulin rings in solution and curved oligomers at the extremities of microtubules in assembly conditions. CONCLUSIONS These results suggest that CLIP-170 targets specifically at microtubule plus ends by copolymerizing with tubulin and modulates microtubule nucleation, polymerization, and rescues by the same basic mechanism with tubulin oligomers as intermediates.
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Affiliation(s)
- Isabelle Arnal
- Equipe Structure et Dynamique des Macromolécules, Unité Mixte de Recherche 6026, Centre National de la Recherche Scientifique, Université de Rennes 1, Campus de Beaulieu, 35042 Rennes Cedex, France.
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