551
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Nashchekin D, Fernandes AR, St Johnston D. Patronin/Shot Cortical Foci Assemble the Noncentrosomal Microtubule Array that Specifies the Drosophila Anterior-Posterior Axis. Dev Cell 2017; 38:61-72. [PMID: 27404359 PMCID: PMC4943857 DOI: 10.1016/j.devcel.2016.06.010] [Citation(s) in RCA: 111] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 05/03/2016] [Accepted: 06/08/2016] [Indexed: 02/06/2023]
Abstract
Noncentrosomal microtubules play an important role in polarizing differentiated cells, but little is known about how these microtubules are organized. Here we identify the spectraplakin, Short stop (Shot), as the cortical anchor for noncentrosomal microtubule organizing centers (ncMTOCs) in the Drosophila oocyte. Shot interacts with the cortex through its actin-binding domain and recruits the microtubule minus-end-binding protein, Patronin, to form cortical ncMTOCs. Shot/Patronin foci do not co-localize with γ-tubulin, suggesting that they do not nucleate new microtubules. Instead, they capture and stabilize existing microtubule minus ends, which then template new microtubule growth. Shot/Patronin foci are excluded from the oocyte posterior by the Par-1 polarity kinase to generate the polarized microtubule network that localizes axis determinants. Both proteins also accumulate apically in epithelial cells, where they are required for the formation of apical-basal microtubule arrays. Thus, Shot/Patronin ncMTOCs may provide a general mechanism for organizing noncentrosomal microtubules in differentiated cells. The Drosophila spectraplakin, Shot, recruits Patronin to form noncentrosomal MTOCs The actin-binding domain of Shot anchors the ncMTOCs to the oocyte cortex Par-1 excludes Shot from the posterior cortex to define the anterior-posterior axis Shot/Patronin ncMTOCs lack γ-tubulin and grow MTs from stabilized minus-end stumps
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Affiliation(s)
- Dmitry Nashchekin
- The Gurdon Institute and the Department of Genetics, the University of Cambridge, Cambridge CB2 1QN, UK
| | - Artur Ribeiro Fernandes
- The Gurdon Institute and the Department of Genetics, the University of Cambridge, Cambridge CB2 1QN, UK
| | - Daniel St Johnston
- The Gurdon Institute and the Department of Genetics, the University of Cambridge, Cambridge CB2 1QN, UK.
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552
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Shakhov AS, Alieva IB. The Centrosome as the Main Integrator of Endothelial Cell Functional Activity. BIOCHEMISTRY (MOSCOW) 2017; 82:663-677. [PMID: 28601076 DOI: 10.1134/s0006297917060037] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The centrosome is an intracellular structure of the animal cell responsible for organization of cytoplasmic microtubules. According to modern concepts, the centrosome is a very important integral element of the living cell whose functions are not limited to its ability to polymerize microtubules. The centrosome localization in the geometric center of the interphase cell, the high concentration of various regulatory proteins in this area, the centrosome-organized radial system of microtubules for intracellular transport by motor proteins, the centrosome involvement in the perception of external signals and their transmission - all these features make this cellular structure a unique regulation and distribution center managing dynamic morphology of the animal cell. In conjunction with the tissue-specific features of the centrosome structure, this suggests the direct involvement of the centrosome in execution of cell functions. This review discusses the involvement of the centrosome in the vital activity of endothelial cells, as well as its possible participation in the implementation of barrier function, the major function of endothelium.
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Affiliation(s)
- A S Shakhov
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119991, Russia.
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553
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LMD proteomics provides evidence for hippocampus field-specific motor protein abundance changes with relevance to Alzheimer's disease. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2017; 1865:703-714. [DOI: 10.1016/j.bbapap.2017.03.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 03/17/2017] [Accepted: 03/30/2017] [Indexed: 12/13/2022]
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554
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Short Linear Sequence Motif LxxPTPh Targets Diverse Proteins to Growing Microtubule Ends. Structure 2017; 25:924-932.e4. [DOI: 10.1016/j.str.2017.04.010] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Revised: 04/06/2017] [Accepted: 04/28/2017] [Indexed: 11/23/2022]
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555
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Chlamydia Hijacks ARF GTPases To Coordinate Microtubule Posttranslational Modifications and Golgi Complex Positioning. mBio 2017; 8:mBio.02280-16. [PMID: 28465429 PMCID: PMC5414008 DOI: 10.1128/mbio.02280-16] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The intracellular bacterium Chlamydia trachomatis develops in a parasitic compartment called the inclusion. Posttranslationally modified microtubules encase the inclusion, controlling the positioning of Golgi complex fragments around the inclusion. The molecular mechanisms by which Chlamydia coopts the host cytoskeleton and the Golgi complex to sustain its infectious compartment are unknown. Here, using a genetically modified Chlamydia strain, we discovered that both posttranslationally modified microtubules and Golgi complex positioning around the inclusion are controlled by the chlamydial inclusion protein CT813/CTL0184/InaC and host ARF GTPases. CT813 recruits ARF1 and ARF4 to the inclusion membrane, where they induce posttranslationally modified microtubules. Similarly, both ARF isoforms are required for the repositioning of Golgi complex fragments around the inclusion. We demonstrate that CT813 directly recruits ARF GTPases on the inclusion membrane and plays a pivotal role in their activation. Together, these results reveal that Chlamydia uses CT813 to hijack ARF GTPases to couple posttranslationally modified microtubules and Golgi complex repositioning at the inclusion. Chlamydia trachomatis is an important cause of morbidity and a significant economic burden in the world. However, how Chlamydia develops its intracellular compartment, the so-called inclusion, is poorly understood. Using genetically engineered Chlamydia mutants, we discovered that the effector protein CT813 recruits and activates host ADP-ribosylation factor 1 (ARF1) and ARF4 to regulate microtubules. In this context, CT813 acts as a molecular platform that induces the posttranslational modification of microtubules around the inclusion. These cages are then used to reposition the Golgi complex during infection and promote the development of the inclusion. This study provides the first evidence that ARF1 and ARF4 play critical roles in controlling posttranslationally modified microtubules around the inclusion and that Chlamydia trachomatis hijacks this novel function of ARF to reposition the Golgi complex.
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556
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Sulimenko V, Hájková Z, Klebanovych A, Dráber P. Regulation of microtubule nucleation mediated by γ-tubulin complexes. PROTOPLASMA 2017; 254:1187-1199. [PMID: 28074286 DOI: 10.1007/s00709-016-1070-z] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Accepted: 12/22/2016] [Indexed: 05/18/2023]
Abstract
The microtubule cytoskeleton is critically important for spatio-temporal organization of eukaryotic cells. The nucleation of new microtubules is typically restricted to microtubule organizing centers (MTOCs) and requires γ-tubulin that assembles into multisubunit complexes of various sizes. γ-Tubulin ring complexes (TuRCs) are efficient microtubule nucleators and are associated with large number of targeting, activating and modulating proteins. γ-Tubulin-dependent nucleation of microtubules occurs both from canonical MTOCs, such as spindle pole bodies and centrosomes, and additional sites such as Golgi apparatus, nuclear envelope, plasma membrane-associated sites, chromatin and surface of pre-existing microtubules. Despite many advances in structure of γ-tubulin complexes and characterization of γTuRC interacting factors, regulatory mechanisms of microtubule nucleation are not fully understood. Here, we review recent work on the factors and regulatory mechanisms that are involved in centrosomal and non-centrosomal microtubule nucleation.
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Affiliation(s)
- Vadym Sulimenko
- Department of Biology of Cytoskeleton, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Vídeňská 1083, 142 20, Prague 4, Czech Republic
| | - Zuzana Hájková
- Department of Biology of Cytoskeleton, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Vídeňská 1083, 142 20, Prague 4, Czech Republic
| | - Anastasiya Klebanovych
- Department of Biology of Cytoskeleton, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Vídeňská 1083, 142 20, Prague 4, Czech Republic
| | - Pavel Dráber
- Department of Biology of Cytoskeleton, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Vídeňská 1083, 142 20, Prague 4, Czech Republic.
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557
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Zan J, Liu S, Sun DN, Mo KK, Yan Y, Liu J, Hu BL, Gu JY, Liao M, Zhou JY. Rabies Virus Infection Induces Microtubule Depolymerization to Facilitate Viral RNA Synthesis by Upregulating HDAC6. Front Cell Infect Microbiol 2017; 7:146. [PMID: 28491824 PMCID: PMC5405082 DOI: 10.3389/fcimb.2017.00146] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2016] [Accepted: 04/07/2017] [Indexed: 12/20/2022] Open
Abstract
Rabies virus (RABV) is the cause of rabies, and is associated with severe neurological symptoms, high mortality rate, and a serious threat to human health. Although cellular tubulin has recently been identified to be incorporated into RABV particles, the effects of RABV infection on the microtubule cytoskeleton remain poorly understood. In this study, we show that RABV infection induces microtubule depolymerization as observed by confocal microscopy, which is closely associated with the formation of the filamentous network of the RABV M protein. Depolymerization of microtubules significantly increases viral RNA synthesis, while the polymerization of microtubules notably inhibits viral RNA synthesis and prevents the viral M protein from inducing the formation of the filamentous network. Furthermore, the histone deacetylase 6 (HDAC6) expression level progressively increases during RABV infection, and the inhibition of HDAC6 deacetylase activity significantly decreases viral RNA synthesis. In addition, the expression of viral M protein alone was found to significantly upregulate HDAC6 expression, leading to a substantial reduction in its substrate, acetylated α-tubulin, eventually resulting in microtubule depolymerization. These results demonstrate that HDAC6 plays a positive role in viral transcription and replication by inducing microtubule depolymerization during RABV infection.
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Affiliation(s)
- Jie Zan
- Key Laboratory of Animal Virology of Ministry of Agriculture, Zhejiang UniversityHangzhou, China
| | - Song Liu
- Key Laboratory of Animal Virology of Ministry of Agriculture, Zhejiang UniversityHangzhou, China
| | - Dong-Nan Sun
- Key Laboratory of Animal Virology of Ministry of Agriculture, Zhejiang UniversityHangzhou, China
| | - Kai-Kun Mo
- Key Laboratory of Animal Virology of Ministry of Agriculture, Zhejiang UniversityHangzhou, China
| | - Yan Yan
- Key Laboratory of Animal Virology of Ministry of Agriculture, Zhejiang UniversityHangzhou, China
| | - Juan Liu
- Key Laboratory of Animal Virology of Ministry of Agriculture, Zhejiang UniversityHangzhou, China
| | - Bo-Li Hu
- Institute of Immunology, Nanjing Agricultural UniversityNanjing, China
| | - Jin-Yan Gu
- Collaborative Innovation Center and State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang UniversityHangzhou, China
| | - Min Liao
- Key Laboratory of Animal Virology of Ministry of Agriculture, Zhejiang UniversityHangzhou, China
| | - Ji-Yong Zhou
- Key Laboratory of Animal Virology of Ministry of Agriculture, Zhejiang UniversityHangzhou, China.,Collaborative Innovation Center and State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang UniversityHangzhou, China
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558
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Characterization of microtubule buckling in living cells. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2017; 46:581-594. [PMID: 28424847 DOI: 10.1007/s00249-017-1207-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 03/15/2017] [Accepted: 04/03/2017] [Indexed: 10/19/2022]
Abstract
Microtubules are filamentous biopolymers involved in essential biological processes. They form key structures in eukaryotic cells, and thus it is very important to determine the mechanisms involved in the formation and maintenance of the microtubule network. Microtubule bucklings are transient and localized events commonly observed in living cells and characterized by a fast bending and its posterior relaxation. Active forces provided by molecular motors have been indicated as responsible for most of these rapid deformations. However, the factors that control the shape amplitude and the time scales of the rising and release stages remain unexplored. In this work, we study microtubule buckling in living cells using Xenopus laevis melanophores as a model system. We tracked single fluorescent microtubules from high temporal resolution (0.3-2 s) confocal movies. We recovered the center coordinates of the filaments with 10-nm precision and analyzed the amplitude of the deformation as a function of time. Using numerical simulations, we explored different force mechanisms resulting in microtubule bending. The simulated events reproduce many features observed for microtubules, suggesting that a mechanistic model captures the essential processes underlying microtubule buckling. Also, we studied the interplay between actively transported vesicles and the microtubule network using a two-color technique. Our results suggest that microtubules may affect transport indirectly besides serving as tracks of motor-driven organelles. For example, they could obstruct organelles at microtubule intersections or push them during filament mechanical relaxation.
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559
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Baumbach J, Murthy A, McClintock MA, Dix CI, Zalyte R, Hoang HT, Bullock SL. Lissencephaly-1 is a context-dependent regulator of the human dynein complex. eLife 2017; 6. [PMID: 28406398 PMCID: PMC5413349 DOI: 10.7554/elife.21768] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 04/11/2017] [Indexed: 01/19/2023] Open
Abstract
The cytoplasmic dynein-1 (dynein) motor plays a central role in microtubule organisation and cargo transport. These functions are spatially regulated by association of dynein and its accessory complex dynactin with dynamic microtubule plus ends. Here, we elucidate in vitro the roles of dynactin, end-binding protein-1 (EB1) and Lissencephaly-1 (LIS1) in the interaction of end tracking and minus end-directed human dynein complexes with these sites. LIS1 promotes dynactin-dependent tracking of dynein on both growing and shrinking plus ends. LIS1 also increases the frequency and velocity of processive dynein movements that are activated by complex formation with dynactin and a cargo adaptor. This stimulatory effect of LIS1 contrasts sharply with its documented ability to inhibit the activity of isolated dyneins. Collectively, our findings shed light on how mammalian dynein complexes associate with dynamic microtubules and help clarify how LIS1 promotes the plus-end localisation and cargo transport functions of dynein in vivo. DOI:http://dx.doi.org/10.7554/eLife.21768.001
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Affiliation(s)
- Janina Baumbach
- Division of Cell Biology, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Andal Murthy
- Division of Cell Biology, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom.,Division of Structural Studies, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Mark A McClintock
- Division of Cell Biology, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Carly I Dix
- Division of Cell Biology, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Ruta Zalyte
- Division of Structural Studies, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Ha Thi Hoang
- Division of Cell Biology, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Simon L Bullock
- Division of Cell Biology, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
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560
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Abstract
Exocytosis is a fundamental cellular process whereby secreted molecules are packaged into vesicles that move along cytoskeletal filaments and fuse with the plasma membrane. To function optimally, cells are strongly dependent on precisely controlled delivery of exocytotic cargo. In mammalian cells, microtubules serve as major tracks for vesicle transport by motor proteins, and thus microtubule organization is important for targeted delivery of secretory carriers. Over the years, multiple microtubule-associated and cortical proteins have been discovered that facilitate the interaction between the microtubule plus ends and the cell cortex. In this review, we focus on mammalian protein complexes that have been shown to participate in both cortical microtubule capture and exocytosis, thereby regulating the spatial organization of secretion. These complexes include microtubule plus-end tracking proteins, scaffolding factors, actin-binding proteins, and components of vesicle docking machinery, which together allow efficient coordination of cargo transport and release.
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Affiliation(s)
- Ivar Noordstra
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, Netherlands
| | - Anna Akhmanova
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, Netherlands
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561
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Benbow SJ, Wozniak KM, Kulesh B, Savage A, Slusher BS, Littlefield BA, Jordan MA, Wilson L, Feinstein SC. Microtubule-Targeting Agents Eribulin and Paclitaxel Differentially Affect Neuronal Cell Bodies in Chemotherapy-Induced Peripheral Neuropathy. Neurotox Res 2017; 32:151-162. [PMID: 28391556 DOI: 10.1007/s12640-017-9729-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 03/21/2017] [Accepted: 03/27/2017] [Indexed: 01/05/2023]
Abstract
Chemotherapy-induced peripheral neuropathy (CIPN) is a common side effect of anticancer treatment with microtubule-targeted agents (MTAs). The frequency of severe CIPN, which can be dose limiting and even life threatening, varies widely among different MTAs. For example, paclitaxel induces a higher frequency of severe CIPN than does eribulin. Different MTAs also possess distinct mechanisms of microtubule-targeted action. Recently, we demonstrated that paclitaxel and eribulin differentially affect sciatic nerve axons, with paclitaxel inducing more pronounced neurodegenerative effects and eribulin inducing greater microtubule stabilizing biochemical effects. Here, we complement and extend these axonal studies by assessing the effects of paclitaxel and eribulin in the cell bodies of sciatic nerve axons, housed in the dorsal root ganglia (DRG). Importantly, the microtubule network in cell bodies is known to be significantly more dynamic than in axons. Paclitaxel induced activating transcription factor 3 expression, a marker of neuronal stress/injury. Paclitaxel also increased expression levels of acetylated tubulin and end binding protein 1, markers of microtubule stability and growth, respectively. These effects are hypothesized to be detrimental to the dynamic microtubule network within the cell bodies. In contrast, eribulin had no significant effect on any of these parameters in the cell bodies. Taken together, DRG cell bodies and their axons, two distinct neuronal cell compartments, contain functionally distinct microtubule networks that exhibit unique biochemical responses to different MTA treatments. We hypothesize that these distinct mechanistic actions may underlie the variability seen in the initiation, progression, persistence, and recovery from CIPN.
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Affiliation(s)
- Sarah J Benbow
- Neuroscience Research Institute, University of California, Santa Barbara, CA, 93106, USA.,Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, CA, USA
| | - Krystyna M Wozniak
- Johns Hopkins Drug Discovery Program, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Bridget Kulesh
- Neuroscience Research Institute, University of California, Santa Barbara, CA, 93106, USA.,Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, CA, USA
| | - April Savage
- Neuroscience Research Institute, University of California, Santa Barbara, CA, 93106, USA.,Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, CA, USA
| | - Barbara S Slusher
- Johns Hopkins Drug Discovery Program, Johns Hopkins School of Medicine, Baltimore, MD, USA.,Departments of Neurology, Psychiatry, Neuroscience, Medicine and Oncology, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | | | - Mary Ann Jordan
- Neuroscience Research Institute, University of California, Santa Barbara, CA, 93106, USA.,Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, CA, USA
| | - Leslie Wilson
- Neuroscience Research Institute, University of California, Santa Barbara, CA, 93106, USA.,Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, CA, USA
| | - Stuart C Feinstein
- Neuroscience Research Institute, University of California, Santa Barbara, CA, 93106, USA. .,Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, CA, USA.
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562
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Gao Y, Chen H, Lui WY, Lee WM, Cheng CY. Basement Membrane Laminin α2 Regulation of BTB Dynamics via Its Effects on F-Actin and Microtubule Cytoskeletons Is Mediated Through mTORC1 Signaling. Endocrinology 2017; 158:963-978. [PMID: 28323988 PMCID: PMC5460804 DOI: 10.1210/en.2016-1630] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Accepted: 01/11/2017] [Indexed: 11/19/2022]
Abstract
A local axis connects the apical ectoplasmic specialization (ES) at the Sertoli-spermatid interface, the basal ES at the blood-testis barrier (BTB), and the basement membrane across the seminiferous epithelium functionally in rat testes. As such, cellular events that take place simultaneously across the epithelium such as spermiation and BTB remodeling that occur at the apical ES and the basal ES, respectively, at stage VIII of the cycle are coordinated. Herein, laminin α2, a structural component of the basement membrane, was found to regulate BTB dynamics. Sertoli cells were cultured in vitro to allow the establishment of a tight junction (TJ) barrier that mimicked the BTB in vivo. Knockdown of laminin α2 by transfecting Sertoli cells with laminin α2-specific short hairpin RNA vs the nontargeting negative control was shown to perturb the Sertoli cell TJ barrier, illustrating laminin α2 was involved in regulating BTB dynamics. This regulatory effect was mediated through mammalian target of rapamycin complex 1 (mTORC1) signaling because the two mTORC1 downstream signaling molecules ribosomal protein S6 and Akt1/2 were activated and inactivated, respectively, consistent with earlier findings that mTORC1 is involved in promoting BTB remodeling. Also, laminin α2 knockdown induced F-actin and microtubule (MT) disorganization through changes in the spatial expression of F-actin regulators actin-related protein 3 and epidermal growth factor receptor pathway substrate 8 vs end-binding protein 1 (a MT plus-end tracking protein, +TIP). These laminin α2 knockdown-mediated effects on F-actin and MT organization was blocked by exposing Sertoli cells to rapamycin, an inhibitor of mTORC1 signaling, and also SC79, an activator of Akt. In summary, laminin α2-mediated regulation on Sertoli cell BTB dynamics is through mTORC1 signaling.
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Affiliation(s)
- Ying Gao
- The Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, New York, New York 10065
| | - Haiqi Chen
- The Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, New York, New York 10065
| | - Wing-yee Lui
- School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China
| | - Will M. Lee
- School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China
| | - C. Yan Cheng
- The Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, New York, New York 10065
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563
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Mechanistic and therapeutic perspectives for cardiac arrhythmias: beyond ion channels. SCIENCE CHINA-LIFE SCIENCES 2017; 60:348-355. [DOI: 10.1007/s11427-016-9005-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Accepted: 12/20/2016] [Indexed: 10/19/2022]
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564
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Fong KW, Au FKC, Jia Y, Yang S, Zhou L, Qi RZ. Microtubule plus-end tracking of end-binding protein 1 (EB1) is regulated by CDK5 regulatory subunit-associated protein 2. J Biol Chem 2017; 292:7675-7687. [PMID: 28320860 DOI: 10.1074/jbc.m116.759746] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Revised: 03/15/2017] [Indexed: 01/08/2023] Open
Abstract
Microtubules are polar cytoskeleton filaments that extend via growth at their plus ends. Microtubule plus-end-tracking proteins (+TIPs) accumulate at these growing plus ends to control microtubule dynamics and attachment. The +TIP end-binding protein 1 (EB1) and its homologs possess an autonomous plus-end-tracking mechanism and interact with other known +TIPs, which then recruit those +TIPs to the growing plus ends. A major +TIP class contains the SXIP (Ser-X-Ile-Pro, with X denoting any amino acid residue) motif, known to interact with EB1 and its homologs for plus-end tracking, but the role of SXIP in regulating EB1 activities is unclear. We show here that an interaction of EB1 with the SXIP-containing +TIP CDK5 regulatory subunit-associated protein 2 (CDK5RAP2) regulates several EB1 activities, including microtubule plus-end tracking, dynamics at microtubule plus ends, microtubule and α/β-tubulin binding, and microtubule polymerization. The SXIP motif fused with a dimerization domain from CDK5RAP2 significantly enhanced EB1 plus-end-tracking and microtubule-polymerizing and bundling activities, but the SXIP motif alone failed to do so. An SXIP-binding-deficient EB1 mutant displayed significantly lower microtubule plus-end tracking than the wild-type protein in transfected cells. These results suggest that EB1 cooperates with CDK5RAP2 and perhaps other SXIP-containing +TIPs in tracking growing microtubule tips. We also generated plus-end-tracking chimeras of CDK5RAP2 and the adenomatous polyposis coli protein (APC) and found that overexpression of the dimerization domains interfered with microtubule plus-end tracking of their respective SXIP-containing chimeras. Our results suggest that disruption of SXIP dimerization enables detailed investigations of microtubule plus-end-associated functions of individual SXIP-containing +TIPs.
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Affiliation(s)
- Ka-Wing Fong
- From the Division of Life Science and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Franco K C Au
- From the Division of Life Science and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Yue Jia
- From the Division of Life Science and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Shaozhong Yang
- From the Division of Life Science and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Liying Zhou
- From the Division of Life Science and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Robert Z Qi
- From the Division of Life Science and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
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565
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van Riel WE, Rai A, Bianchi S, Katrukha EA, Liu Q, Heck AJ, Hoogenraad CC, Steinmetz MO, Kapitein LC, Akhmanova A. Kinesin-4 KIF21B is a potent microtubule pausing factor. eLife 2017; 6. [PMID: 28290984 PMCID: PMC5383399 DOI: 10.7554/elife.24746] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Accepted: 03/09/2017] [Indexed: 12/20/2022] Open
Abstract
Microtubules are dynamic polymers that in cells can grow, shrink or pause, but the factors that promote pausing are poorly understood. Here, we show that the mammalian kinesin-4 KIF21B is a processive motor that can accumulate at microtubule plus ends and induce pausing. A few KIF21B molecules are sufficient to induce strong growth inhibition of a microtubule plus end in vitro. This property depends on non-motor microtubule-binding domains located in the stalk region and the C-terminal WD40 domain. The WD40-containing KIF21B tail displays preference for a GTP-type over a GDP-type microtubule lattice and contributes to the interaction of KIF21B with microtubule plus ends. KIF21B also contains a motor-inhibiting domain that does not fully block the interaction of the protein with microtubules, but rather enhances its pause-inducing activity by preventing KIF21B detachment from microtubule tips. Thus, KIF21B combines microtubule-binding and regulatory activities that together constitute an autonomous microtubule pausing factor. DOI:http://dx.doi.org/10.7554/eLife.24746.001 Microtubules are tiny tubes that cells use as rails to move various cell compartments and structures to different locations within the cell. They are made of building blocks called tubulin and form extensive networks across the cell. Depending on the cell’s needs, microtubule networks can be rapidly assembled and disassembled by adding or removing tubulin subunits at the ends of individual microtubules. While a lot is known about how cells regulate the growth and shrinkage of microtubules, much less is known about the factors that can pause these processes and thus stabilize a microtubule. Proteins belonging to the kinesin family are molecular motors that can walk along microtubules and control how microtubules grow and shrink. A kinesin known as KIF21B is found in several types of cells including neurons and immune cells and genetic alterations in this protein have been linked with several neurodegenerative diseases. KIF21B is made up of three regions: a motor domain, a stalk and a tail domain that binds to microtubules. Recent studies have suggested that this kinesin affects the ability of one end of microtubules (known as the plus end) to grow. Here, van Riel, Rai, Bianchi et al. used a biochemical approach to investigate the activity of KIF21B. The experiments show that KIF21B can walk to the plus end of microtubules and efficiently pause growth. Small numbers of KIF21B molecules are enough to inhibit microtubule growth and this activity depends on the motor domain and the tail domain of KIF21B working together. These experiments were performed a cell-free system and so the next challenge is to investigate how KIF21B works in living cells, including neurons and immune cells. DOI:http://dx.doi.org/10.7554/eLife.24746.002
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Affiliation(s)
- Wilhelmina E van Riel
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, Utrecht, Netherlands
| | - Ankit Rai
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, Utrecht, Netherlands
| | - Sarah Bianchi
- Laboratory of Biomolecular Research, Department of Biology and Chemistry, Paul Scherrer Institut, Villigen PSI, Switzerland
| | - Eugene A Katrukha
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, Utrecht, Netherlands
| | - Qingyang Liu
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, Utrecht, Netherlands
| | - Albert Jr Heck
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research, Utrecht Institute for Pharmaceutical Sciences and The Netherlands Proteomics Centre, Utrecht University, Utrecht, Netherlands
| | - Casper C Hoogenraad
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, Utrecht, Netherlands
| | - Michel O Steinmetz
- Laboratory of Biomolecular Research, Department of Biology and Chemistry, Paul Scherrer Institut, Villigen PSI, Switzerland
| | - Lukas C Kapitein
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, Utrecht, Netherlands
| | - Anna Akhmanova
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, Utrecht, Netherlands
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566
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Nishita M, Satake T, Minami Y, Suzuki A. Regulatory mechanisms and cellular functions of non-centrosomal microtubules. J Biochem 2017; 162:1-10. [DOI: 10.1093/jb/mvx018] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 03/02/2017] [Indexed: 02/07/2023] Open
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567
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Steady-state EB cap size fluctuations are determined by stochastic microtubule growth and maturation. Proc Natl Acad Sci U S A 2017; 114:3427-3432. [PMID: 28280102 DOI: 10.1073/pnas.1620274114] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Growing microtubules are protected from depolymerization by the presence of a GTP or GDP/Pi cap. End-binding proteins of the EB1 family bind to the stabilizing cap, allowing monitoring of its size in real time. The cap size has been shown to correlate with instantaneous microtubule stability. Here we have quantitatively characterized the properties of cap size fluctuations during steady-state growth and have developed a theory predicting their timescale and amplitude from the kinetics of microtubule growth and cap maturation. In contrast to growth speed fluctuations, cap size fluctuations show a characteristic timescale, which is defined by the lifetime of the cap sites. Growth fluctuations affect the amplitude of cap size fluctuations; however, cap size does not affect growth speed, indicating that microtubules are far from instability during most of their time of growth. Our theory provides the basis for a quantitative understanding of microtubule stability fluctuations during steady-state growth.
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568
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Robison P, Prosser BL. Microtubule mechanics in the working myocyte. J Physiol 2017; 595:3931-3937. [PMID: 28116814 DOI: 10.1113/jp273046] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Accepted: 12/05/2016] [Indexed: 11/08/2022] Open
Abstract
The mechanical role of cardiac microtubules (MTs) has been a topic of some controversy. Early studies, which relied largely on pharmacological interventions that altered the MT cytoskeleton as a whole, presented no consistent role. Recent advances in the ability to observe and manipulate specific properties of the cytoskeleton have strengthened our understanding. Direct observation of MTs in working myocytes suggests a spring-like function, one that is surprisingly tunable by post-translational modification (PTM). Specifically, detyrosination of MTs facilitates an interaction with intermediate filaments that complex with the sarcomere, altering myocyte stiffness, contractility, and mechanosignalling. Such results support a paradigm of cytoskeletal regulation based on not only polymerization, but also associations with binding partners and PTMs that divide the MT cytoskeleton into functionally distinct subsets. The evolutionary costs and benefits of tuning cytoskeletal mechanics remain an open question, one that we discuss herein. Nevertheless, mechanically distinct MT subsets provide a rich new source of therapeutic targets for a variety of phenomena in the heart.
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Affiliation(s)
- Patrick Robison
- Department of Physiology, Pennsylvania Muscle Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104, USA
| | - Benjamin L Prosser
- Department of Physiology, Pennsylvania Muscle Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104, USA
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569
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EB1 contributes to proper front-to-back polarity in neutrophil-like HL-60 cells. Eur J Cell Biol 2017; 96:143-153. [DOI: 10.1016/j.ejcb.2017.01.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Revised: 12/10/2016] [Accepted: 01/16/2017] [Indexed: 12/30/2022] Open
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570
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Anti-leukemia effects of the novel synthetic 1-benzylindole derivative 21-900 in vitro and in vivo. Sci Rep 2017; 7:42291. [PMID: 28181578 PMCID: PMC5299419 DOI: 10.1038/srep42291] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Accepted: 01/08/2017] [Indexed: 02/08/2023] Open
Abstract
Cancers are the major cause of death worldwide. Chemotherapy using cytotoxic drugs and targeted therapy is required when surgery is difficult, ineffective, or impossible. We previously synthesized the novel synthetic 1-benzylindole derivative 21-900 and found that it inhibits histone deacetylase (HDAC) activities and tubulin assembly. Here we tested its effects on the human leukaemia cell lines HL-60 and MOLT-4 in vitro and in vivo. We found that its potent cytotoxic effects were mediated through cell cycle arrest at the G2/M phase, which increased the population of sub-G1 cells, leading to apoptosis. Further, tubulin was depolymerized by 21-900 in a manner similar to that of vincristine, leading to disruption of microtubule dynamics and increased levels of the mitotic marker MPM-2. Further, 21-900 increased the expression of cleavage form of poly (ADP-ribose) polymerase (PARP), caspase 3, 7 (cleavage form), and pro-apoptotic protein BAK and decreased the expression of pro-survival BCL-2-family proteins BCL-2, MCL-1, and BID pro-form, leading to the induction of apoptosis. The growth of tumours in nude mice formed by xenografts of HL-60 and MOLT-4 cells was significantly inhibited by 21-900 without causing the mice to lose body weight. These findings indicate that 21-900 may serve as a potent anti-leukaemia drug.
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571
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Kapoor TM. Metaphase Spindle Assembly. BIOLOGY 2017; 6:biology6010008. [PMID: 28165376 PMCID: PMC5372001 DOI: 10.3390/biology6010008] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 01/17/2017] [Accepted: 01/19/2017] [Indexed: 01/31/2023]
Abstract
A microtubule-based bipolar spindle is required for error-free chromosome segregation during cell division. In this review I discuss the molecular mechanisms required for the assembly of this dynamic micrometer-scale structure in animal cells.
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Affiliation(s)
- Tarun M Kapoor
- Laboratory of Chemistry and Cell Biology, the Rockefeller University, New York, NY 10065, USA.
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572
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Wong JH, Hashimoto T. Novel Arabidopsis microtubule-associated proteins track growing microtubule plus ends. BMC PLANT BIOLOGY 2017; 17:33. [PMID: 28148225 PMCID: PMC5288973 DOI: 10.1186/s12870-017-0987-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Accepted: 01/25/2017] [Indexed: 05/07/2023]
Abstract
BACKGROUND Microtubules (MTs) are polarized polymers with highly dynamic plus ends that stochastically switch between growth and shrinkage phases. In eukaryotic cells, a plethora of MT-associated proteins (MAPs) regulate the dynamics and higher-order organization of MTs to mediate distinct cellular functions. Plus-end tracking proteins (+TIPs) are a group of MAPs that specifically accumulate at the growing MT plus ends, where they modulate the behavior of the MT plus ends and mediate interactions with cellular targets. Although several functionally important + TIP proteins have been characterized in yeast and animals, little is known about this group of proteins in plants. RESULTS We report here that two homologous MAPs from Arabidopsis thaliana, Growing Plus-end Tracking 1 (GPT1) and GPT2 (henceforth GPT1/2), contain basic MT-binding regions at their central and C-terminal regions, and bind directly to MTs in vitro. Interestingly, GPT1/2 preferentially accumulated at the growing plus ends of cortical MTs in interphase Arabidopsis cells. When the GPT1/12-decorated growing plus ends switched to rapid depolymerization, GPT1/2 dissociated from the MT plus ends. Conversely, when the depolymerizing ends were rescued and started to polymerize again, GPT1/2 were immediately recruited to the growing MT tips. This tip tracking behavior of GPT proteins does not depend on the two established plant + TIPs, End-Binding protein 1 (EB1) and SPIRAL1 (SPR1). CONCLUSIONS The Arabidopsis MAPs GPT1 and GPT2 bind MTs directly through their basic regions. These MAPs track the plus ends of growing MTs independently of EB1 and SPR1 and represent a novel plant-specific + TIP family.
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Affiliation(s)
- Jeh Haur Wong
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Takayama 8916-5, Ikoma, Nara, 630-0192, Japan
| | - Takashi Hashimoto
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Takayama 8916-5, Ikoma, Nara, 630-0192, Japan.
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573
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Insights into the Distinct Mechanisms of Action of Taxane and Non-Taxane Microtubule Stabilizers from Cryo-EM Structures. J Mol Biol 2017; 429:633-646. [PMID: 28104363 DOI: 10.1016/j.jmb.2017.01.001] [Citation(s) in RCA: 124] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Revised: 12/30/2016] [Accepted: 01/03/2017] [Indexed: 01/08/2023]
Abstract
A number of microtubule (MT)-stabilizing agents (MSAs) have demonstrated or predicted potential as anticancer agents, but a detailed structural basis for their mechanism of action is still lacking. We have obtained high-resolution (3.9-4.2Å) cryo-electron microscopy (cryo-EM) reconstructions of MTs stabilized by the taxane-site binders Taxol and zampanolide, and by peloruside, which targets a distinct, non-taxoid pocket on β-tubulin. We find that each molecule has unique distinct structural effects on the MT lattice structure. Peloruside acts primarily at lateral contacts and has an effect on the "seam" of heterologous interactions, enforcing a conformation more similar to that of homologous (i.e., non-seam) contacts by which it regularizes the MT lattice. In contrast, binding of either Taxol or zampanolide induces MT heterogeneity. In doubly bound MTs, peloruside overrides the heterogeneity induced by Taxol binding. Our structural analysis illustrates distinct mechanisms of these drugs for stabilizing the MT lattice and is of relevance to the possible use of combinations of MSAs to regulate MT activity and improve therapeutic potential.
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574
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Takács Z, Jankovics F, Vilmos P, Lénárt P, Röper K, Erdélyi M. The spectraplakin Short stop is an essential microtubule regulator involved in epithelial closure in Drosophila. J Cell Sci 2017; 130:712-724. [PMID: 28062848 PMCID: PMC5339884 DOI: 10.1242/jcs.193003] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Accepted: 12/21/2016] [Indexed: 02/04/2023] Open
Abstract
Dorsal closure of the Drosophila embryonic epithelium provides an excellent model system for the in vivo analysis of molecular mechanisms regulating cytoskeletal rearrangements. In this study, we investigated the function of the Drosophila spectraplakin Short stop (Shot), a conserved cytoskeletal structural protein, during closure of the dorsal embryonic epithelium. We show that Shot is essential for the efficient final zippering of the opposing epithelial margins. By using isoform-specific mutant alleles and genetic rescue experiments with truncated Shot variants, we demonstrate that Shot functions as an actin-microtubule cross-linker in mediating zippering. At the leading edge of epithelial cells, Shot regulates protrusion dynamics by promoting filopodia formation. Fluorescence recovery after photobleaching (FRAP) analysis and in vivo imaging of microtubule growth revealed that Shot stabilizes dynamic microtubules. The actin- and microtubule-binding activities of Shot are simultaneously required in the same molecule, indicating that Shot is engaged as a physical crosslinker in this process. We propose that Shot-mediated interactions between microtubules and actin filaments facilitate filopodia formation, which promotes zippering by initiating contact between opposing epithelial cells.
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Affiliation(s)
- Zsanett Takács
- Institute of Genetics, Biological Research Centre of the Hungarian Academy of Sciences, Temesvári krt. 62, Szeged 6726, Hungary
| | - Ferenc Jankovics
- Institute of Genetics, Biological Research Centre of the Hungarian Academy of Sciences, Temesvári krt. 62, Szeged 6726, Hungary
| | - Péter Vilmos
- Institute of Genetics, Biological Research Centre of the Hungarian Academy of Sciences, Temesvári krt. 62, Szeged 6726, Hungary
| | - Péter Lénárt
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, Heidelberg 69117, Germany
| | - Katja Röper
- MRC-Laboratory of Molecular Biology, Cambridge Biomedical Campus, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Miklós Erdélyi
- Institute of Genetics, Biological Research Centre of the Hungarian Academy of Sciences, Temesvári krt. 62, Szeged 6726, Hungary
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575
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Olziersky AM, Labidi-Galy SI. Clinical Development of Anti-mitotic Drugs in Cancer. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1002:125-152. [PMID: 28600785 DOI: 10.1007/978-3-319-57127-0_6] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Mitosis is one of the most fundamental processes of life by which a mammalian cell divides into two daughter cells. Mitosis has been an attractive target for anticancer therapies since fast proliferation was identified as one of the hallmarks of cancer cells. Despite efforts into developing specific inhibitors for mitotic kinases and kinesins, very few drugs have shown the efficiency of microtubule targeting-agents in cancer cells with paclitaxel being the most successful. A deeper translational research accompanying clinical trials of anti-mitotic drugs will help in identifying potent biomarkers predictive for response. Here, we review the current knowledge of mitosis targeting agents that have been tested so far in the clinics.
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Affiliation(s)
- Anna-Maria Olziersky
- Department of Cell Physiology and Metabolism, Faculty of Medicine, Geneva University, Geneva, Switzerland
| | - S Intidhar Labidi-Galy
- Department of Oncology, Geneva University Hospitals, Rue Gabrielle Perret-Gentil 4, Geneva, 1205, Switzerland.
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576
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Xie S, Zhou J. Harnessing Plant Biodiversity for the Discovery of Novel Anticancer Drugs Targeting Microtubules. FRONTIERS IN PLANT SCIENCE 2017; 8:720. [PMID: 28523014 PMCID: PMC5415602 DOI: 10.3389/fpls.2017.00720] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 04/19/2017] [Indexed: 05/10/2023]
Abstract
The microtubule cytoskeleton plays a critical role in a wide range of cellular activities and has been shown to be a highly effective target for the treatment of human malignancies. Despite the recent focus on proteomics and high-throughput profiling, it is clear that analysis of plant extracts has yielded several highly efficacious microtubule-targeting agents (MTAs) currently in clinical use, as well as agents in the current pipeline with promising efficacy. To date, a large proportion of the world's plant biodiversity remains untapped by the pharmaceutical industry, presenting a major opportunity for the discovery of novel pharmacologically active lead compounds. Because plants contain an astonishing array of structurally diverse molecules, they represent an ideal source for the discovery of novel MTA leads. To demonstrate the importance of searching for novel bioactive compounds across the plant kingdom, herein, we summarize the discovery and development of plant-derived MTAs and discuss the challenges associated with searching for novel bioactive compounds from plants. We propose potential solutions to these problems with the aim of facilitating further exploration and identification of novel MTAs from plant biodiversity.
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577
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Prezel E, Stoppin-Mellet V, Elie A, Zala N, Denarier E, Serre L, Arnal I. TIRF assays for real-time observation of microtubules and actin coassembly: Deciphering tau effects on microtubule/actin interplay. Methods Cell Biol 2017; 141:199-214. [DOI: 10.1016/bs.mcb.2017.06.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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578
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Nieuwburg R, Nashchekin D, Jakobs M, Carter AP, Khuc Trong P, Goldstein RE, St Johnston D. Localised dynactin protects growing microtubules to deliver oskar mRNA to the posterior cortex of the Drosophila oocyte. eLife 2017; 6:e27237. [PMID: 29035202 PMCID: PMC5643094 DOI: 10.7554/elife.27237] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Accepted: 09/19/2017] [Indexed: 11/13/2022] Open
Abstract
The localisation of oskar mRNA to the posterior of the Drosophila oocyte defines where the abdomen and germ cells form in the embryo. Kinesin 1 transports oskar mRNA to the oocyte posterior along a polarised microtubule cytoskeleton that grows from non-centrosomal microtubule organising centres (ncMTOCs) along the anterior/lateral cortex. Here, we show that the formation of this polarised microtubule network also requires the posterior regulation of microtubule growth. A missense mutation in the dynactin Arp1 subunit causes most oskar mRNA to localise in the posterior cytoplasm rather than cortically. oskar mRNA transport and anchoring are normal in this mutant, but the microtubules fail to reach the posterior pole. Thus, dynactin acts as an anti-catastrophe factor that extends microtubule growth posteriorly. Kinesin 1 transports dynactin to the oocyte posterior, creating a positive feedback loop that increases the length and persistence of the posterior microtubules that deliver oskar mRNA to the cortex.
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Affiliation(s)
- Ross Nieuwburg
- The Gurdon Institute and the Department of GeneticsUniversity of CambridgeCambridgeUnited Kingdom
| | - Dmitry Nashchekin
- The Gurdon Institute and the Department of GeneticsUniversity of CambridgeCambridgeUnited Kingdom
| | - Maximilian Jakobs
- The Department of Physiology, Development and NeuroscienceUniversity of CambridgeCambridgeUnited Kingdom
| | - Andrew P Carter
- Division of Structural StudiesMedical Research Council, Laboratory of Molecular BiologyCambridgeUnited Kingdom
| | - Philipp Khuc Trong
- Department of Applied Mathematics and Theoretical PhysicsUniversity of Cambridge, Centre for Mathematical SciencesCambridgeUnited Kingdom
| | - Raymond E Goldstein
- Department of Applied Mathematics and Theoretical PhysicsUniversity of Cambridge, Centre for Mathematical SciencesCambridgeUnited Kingdom
| | - Daniel St Johnston
- The Gurdon Institute and the Department of GeneticsUniversity of CambridgeCambridgeUnited Kingdom
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579
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Abstract
ABSTRACT
Three-dimensional (3D) cell motility underlies essential processes, such as embryonic development, tissue repair and immune surveillance, and is involved in cancer progression. Although the cytoskeleton is a well-studied regulator of cell migration, most of what we know about its functions originates from studies conducted in two-dimensional (2D) cultures. This research established that the microtubule network mediates polarized trafficking and signaling that are crucial for cell shape and movement in 2D. In parallel, developments in light microscopy and 3D cell culture systems progressively allowed to investigate cytoskeletal functions in more physiologically relevant settings. Interestingly, several studies have demonstrated that microtubule involvement in cell morphogenesis and motility can differ in 2D and 3D environments. In this Commentary, we discuss these differences and their relevance for the understanding the role of microtubules in cell migration in vivo. We also provide an overview of microtubule functions that were shown to control cell shape and motility in 3D matrices and discuss how they can be investigated further by using physiologically relevant models.
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Affiliation(s)
- Benjamin P. Bouchet
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, Utrecht 3584 CH, The Netherlands
| | - Anna Akhmanova
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, Utrecht 3584 CH, The Netherlands
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580
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Al-Jassar C, Andreeva A, Barnabas DD, McLaughlin SH, Johnson CM, Yu M, van Breugel M. The Ciliopathy-Associated Cep104 Protein Interacts with Tubulin and Nek1 Kinase. Structure 2016; 25:146-156. [PMID: 28017521 PMCID: PMC5222566 DOI: 10.1016/j.str.2016.11.014] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2016] [Revised: 11/04/2016] [Accepted: 11/18/2016] [Indexed: 12/26/2022]
Abstract
Cilia are thin cell projections with essential roles in cell motility, fluid movement, sensing, and signaling. They are templated from centrioles that dock against the plasma membrane and subsequently extend their peripheral microtubule array. The molecular mechanisms underpinning cilia assembly are incompletely understood. Cep104 is a key factor involved in cilia formation and length regulation that rides on the ends of elongating and shrinking cilia. It is mutated in Joubert syndrome, a genetically heterogeneous ciliopathy. Here we provide structural and biochemical data that Cep104 contains a tubulin-binding TOG (tumor overexpressed gene) domain and a novel C2HC zinc finger array. Furthermore, we identify the kinase Nek1, another ciliopathy-associated protein, as a potential binding partner of this array. Finally, we show that Nek1 competes for binding to Cep104 with the distal centriole-capping protein CP110. Our data suggest a model for Cep104 activity during ciliogenesis and provide a novel link between Cep104 and Nek1.
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Affiliation(s)
- Caezar Al-Jassar
- Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Antonina Andreeva
- Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Deepak D Barnabas
- Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Stephen H McLaughlin
- Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Christopher M Johnson
- Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Minmin Yu
- Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Mark van Breugel
- Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK.
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581
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Scholey JM, Civelekoglu-Scholey G, Brust-Mascher I. Anaphase B. BIOLOGY 2016; 5:biology5040051. [PMID: 27941648 PMCID: PMC5192431 DOI: 10.3390/biology5040051] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 11/30/2016] [Accepted: 12/01/2016] [Indexed: 11/16/2022]
Abstract
Anaphase B spindle elongation is characterized by the sliding apart of overlapping antiparallel interpolar (ip) microtubules (MTs) as the two opposite spindle poles separate, pulling along disjoined sister chromatids, thereby contributing to chromosome segregation and the propagation of all cellular life. The major biochemical “modules” that cooperate to mediate pole–pole separation include: (i) midzone pushing or (ii) braking by MT crosslinkers, such as kinesin-5 motors, which facilitate or restrict the outward sliding of antiparallel interpolar MTs (ipMTs); (iii) cortical pulling by disassembling astral MTs (aMTs) and/or dynein motors that pull aMTs outwards; (iv) ipMT plus end dynamics, notably net polymerization; and (v) ipMT minus end depolymerization manifest as poleward flux. The differential combination of these modules in different cell types produces diversity in the anaphase B mechanism. Combinations of antagonist modules can create a force balance that maintains the dynamic pre-anaphase B spindle at constant length. Tipping such a force balance at anaphase B onset can initiate and control the rate of spindle elongation. The activities of the basic motor filament components of the anaphase B machinery are controlled by a network of non-motor MT-associated proteins (MAPs), for example the key MT cross-linker, Ase1p/PRC1, and various cell-cycle kinases, phosphatases, and proteases. This review focuses on the molecular mechanisms of anaphase B spindle elongation in eukaryotic cells and briefly mentions bacterial DNA segregation systems that operate by spindle elongation.
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Affiliation(s)
- Jonathan M Scholey
- Department of Molecular and Cell Biology, University of California, Davis, CA 95616, USA.
| | | | - Ingrid Brust-Mascher
- Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California, Davis, CA 95616, USA.
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582
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Bouchet BP, Noordstra I, van Amersfoort M, Katrukha EA, Ammon YC, Ter Hoeve ND, Hodgson L, Dogterom M, Derksen PWB, Akhmanova A. Mesenchymal Cell Invasion Requires Cooperative Regulation of Persistent Microtubule Growth by SLAIN2 and CLASP1. Dev Cell 2016; 39:708-723. [PMID: 27939686 DOI: 10.1016/j.devcel.2016.11.009] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Revised: 09/27/2016] [Accepted: 11/10/2016] [Indexed: 11/18/2022]
Abstract
Microtubules regulate signaling, trafficking, and cell mechanics, but the respective contribution of these functions to cell morphogenesis and migration in 3D matrices is unclear. Here, we report that the microtubule plus-end tracking protein (+TIP) SLAIN2, which suppresses catastrophes, is not required for 2D cell migration but is essential for mesenchymal cell invasion in 3D culture and in a mouse cancer model. We show that SLAIN2 inactivation does not affect Rho GTPase activity, trafficking, and focal adhesion formation. However, SLAIN2-dependent catastrophe inhibition determines microtubule resistance to compression and pseudopod elongation. Another +TIP, CLASP1, is also needed to form invasive pseudopods because it prevents catastrophes specifically at their tips. When microtubule growth persistence is reduced, inhibition of depolymerization is sufficient for pseudopod maintenance but not remodeling. We propose that catastrophe inhibition by SLAIN2 and CLASP1 supports mesenchymal cell shape in soft 3D matrices by enabling microtubules to perform a load-bearing function.
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Affiliation(s)
- Benjamin P Bouchet
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Ivar Noordstra
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Miranda van Amersfoort
- Department of Pathology, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands
| | - Eugene A Katrukha
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - York-Christoph Ammon
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Natalie D Ter Hoeve
- Department of Pathology, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands
| | - Louis Hodgson
- Department of Anatomy and Structural Biology, Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, New York 10461, USA
| | - Marileen Dogterom
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ ,Delft, The Netherlands
| | - Patrick W B Derksen
- Department of Pathology, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands
| | - Anna Akhmanova
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
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583
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Ishihara K, Korolev KS, Mitchison TJ. Physical basis of large microtubule aster growth. eLife 2016; 5. [PMID: 27892852 PMCID: PMC5207775 DOI: 10.7554/elife.19145] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Accepted: 11/21/2016] [Indexed: 12/24/2022] Open
Abstract
Microtubule asters - radial arrays of microtubules organized by centrosomes - play a fundamental role in the spatial coordination of animal cells. The standard model of aster growth assumes a fixed number of microtubules originating from the centrosomes. However, aster morphology in this model does not scale with cell size, and we recently found evidence for non-centrosomal microtubule nucleation. Here, we combine autocatalytic nucleation and polymerization dynamics to develop a biophysical model of aster growth. Our model predicts that asters expand as traveling waves and recapitulates all major aspects of aster growth. With increasing nucleation rate, the model predicts an explosive transition from stationary to growing asters with a discontinuous jump of the aster velocity to a nonzero value. Experiments in frog egg extract confirm the main theoretical predictions. Our results suggest that asters observed in large fish and amphibian eggs are a meshwork of short, unstable microtubules maintained by autocatalytic nucleation and provide a paradigm for the assembly of robust and evolvable polymer networks. DOI:http://dx.doi.org/10.7554/eLife.19145.001 Cells must carefully organize their contents in order to work effectively. Protein filaments called microtubules often play important roles in this organization, as well as giving structure to the cell. Many cells contain structures called asters that are formed of microtubules that radiate out from a central point (much like a star shape). Textbooks generally state that all microtubules in the aster grow outward from its center. If this was the case, the microtubules at the edge of large asters – such as those found in frog egg cells and other extremely large cells – would be spread relatively far apart from each other. However, even at the edges of large asters, the microtubules are quite densely packed. In 2014, a group of researchers proposed that new microtubules could form throughout the aster instead of all originating from the center. This model had not been tested; it was also unclear under what conditions an aster would be able to grow to fill a large cell. Ishihara et al. – including some of the researchers involved in the 2014 work – have now developed a mathematical theory of aster growth that is based on the assumption that microtubules stimulate the generation of new microtubules. The theory reproduces the key features seen during the growth of asters in large cells, and predicts that the asters may stay at a constant size or grow continuously. The condition required for the aster to grow is simple: each microtubule in it has to trigger the generation of at least one new microtubule during its lifetime. Ishihara et al. have named this process “collective growth”. Experiments performed using microtubules taken from crushed frog eggs and assembled under a cover slip provided further evidence that asters grow via a collective growth process. Future studies could now investigate whether collective growth also underlies the formation of other cellular structures. DOI:http://dx.doi.org/10.7554/eLife.19145.002
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Affiliation(s)
- Keisuke Ishihara
- Department of Systems Biology, Harvard Medical School, Boston, United States.,Cell Division Group, Marine Biological Laboratory, Woods Hole, United Sates
| | - Kirill S Korolev
- Department of Physics and Graduate Program in Bioinformatics, Boston University, Boston, United States
| | - Timothy J Mitchison
- Department of Systems Biology, Harvard Medical School, Boston, United States.,Cell Division Group, Marine Biological Laboratory, Woods Hole, United Sates
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584
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Wen Q, Tang EI, Xiao X, Gao Y, Chu DS, Mruk DD, Silvestrini B, Cheng CY. Transport of germ cells across the seminiferous epithelium during spermatogenesis-the involvement of both actin- and microtubule-based cytoskeletons. Tissue Barriers 2016; 4:e1265042. [PMID: 28123928 DOI: 10.1080/21688370.2016.1265042] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 11/19/2016] [Accepted: 11/21/2016] [Indexed: 12/16/2022] Open
Abstract
The transport of germ cells from the base of the seminiferous epithelium toward the luminal edge of the tubule lumen in the adluminal compartment during the epithelial cycle is an essential cellular event to support spermatogenesis. Thus, fully developed elongated spermatids (i.e., spermatozoa) can be released at spermiation in late stage VIII in rodents versus late stage II in humans. Earlier studies to examine the molecular mechanism(s) that support germ cell transport, most notably the transport of preleptotene spermatocytes across the blood-testis barrier (BTB), and the transport of elongating spermatids across the adluminal compartment during spermiogenesis, is focused on the adhesion protein complexes at the cell-cell interface. It is generally accepted that cell junctions at the Sertoli cell-cell interface at the BTB, including the actin-based tight junction (TJ), basal ectoplasmic specialization (basal ES, a testis-specific adherens junction) and gap junction (GJ), as well as the intermediate filament-based desmosome undergo constant remodeling to accommodate the transport of preleptotene spermatocytes across the barrier. On the other hand, similar junction dynamics (i.e., disassembly, reassembly and stabilization/maintenance) take place at the Sertoli-spermatid interface. Emerging evidence has shown that junction dynamics at the Sertoli cell-cell vs. Sertoli-germ cell interface are supported by the 2 intriguingly coordinated cytoskeletons, namely the F-actin- and microtubule (MT)-based cytoskeletons. Herein, we provide a brief summary and critically evaluate the recent findings. We also provide an updated hypothetical concept regarding germ cell transport in the testis utilizing the MT-conferred tracks and the MT-specific motor proteins. Furthermore, this cellular event is also supported by the F-actin-based cytoskeleton.
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Affiliation(s)
- Qing Wen
- The Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council , New York, NY, USA
| | - Elizabeth I Tang
- The Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council , New York, NY, USA
| | - Xiang Xiao
- The Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, New York, NY, USA; Department of Reproductive Physiology, Zhejiang Academy of Medical Sciences, Hangzhou, China
| | - Ying Gao
- The Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council , New York, NY, USA
| | - Darren S Chu
- The Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council , New York, NY, USA
| | - Dolores D Mruk
- The Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council , New York, NY, USA
| | | | - C Yan Cheng
- The Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council , New York, NY, USA
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585
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Marzo-Mas A, Barbier P, Breuzard G, Allegro D, Falomir E, Murga J, Carda M, Peyrot V, Marco JA. Interactions of long-chain homologues of colchicine with tubulin. Eur J Med Chem 2016; 126:526-535. [PMID: 27915168 DOI: 10.1016/j.ejmech.2016.11.049] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Revised: 11/21/2016] [Accepted: 11/22/2016] [Indexed: 01/30/2023]
Abstract
Several colchicine analogues in which the N-acetyl residue has been replaced by aliphatic, straight-chain acyl moieties, have been synthesized. These compounds show high cytotoxic activity at the nanomolar level against the tumoral cell lines HT-29, MCF-7 and A549. Some of them exhibit activities in the picomolar range against the HT-29 line and are thus two to three orders of magnitude more cytotoxic than colchicine. In this specific cell line, the activities were found to be closely related to the length of the acyl carbon chain, an increase in the latter giving rise to an increase in the cytotoxicity with a maximum in the range of 10-12 carbon atoms, followed by a decrease in activity with still longer chains. Some of the compounds inhibit microtubule assembly and induce the formation of abnormal polymers and present in most cases better apparent affinity constants than colchicine. In addition, at IC50 concentrations the analogues block the cell cycle of A549 cells in the G2/M phase. Molecular docking studies suggest that, while interactions of the colchicine analogues with the colchicine binding site at β-tubulin are still present, the increase in the acyl chain length leads to the progressive development of new interactions, not present in colchicine itself, with the neighboring α-tubulin subunit. Indeed, sufficiently long acyl chains span the intradimer interface and contact with a hydrophobic groove in α-tubulin. It is worth noting that some of the compounds show cytotoxicity at concentrations three orders of magnitude lower than colchicine. Their pharmacological use in cancer therapy could possibly be performed with lower dosages and be thus endowed with less acute toxicity problems than in the case of colchicine.
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Affiliation(s)
- Ana Marzo-Mas
- Depart. de Q. Inorgánica y Orgánica, Univ. Jaume I, E-12071 Castellón, Spain
| | - Pascale Barbier
- Aix-Marseille Université, Inserm, CRO2 UMR_S 911, Faculté de Pharmacie, 13385, Marseille, France
| | - Gilles Breuzard
- Aix-Marseille Université, Inserm, CRO2 UMR_S 911, Faculté de Pharmacie, 13385, Marseille, France
| | - Diane Allegro
- Aix-Marseille Université, Inserm, CRO2 UMR_S 911, Faculté de Pharmacie, 13385, Marseille, France
| | - Eva Falomir
- Depart. de Q. Inorgánica y Orgánica, Univ. Jaume I, E-12071 Castellón, Spain
| | - Juan Murga
- Depart. de Q. Inorgánica y Orgánica, Univ. Jaume I, E-12071 Castellón, Spain.
| | - Miguel Carda
- Depart. de Q. Inorgánica y Orgánica, Univ. Jaume I, E-12071 Castellón, Spain
| | - Vincent Peyrot
- Aix-Marseille Université, Inserm, CRO2 UMR_S 911, Faculté de Pharmacie, 13385, Marseille, France.
| | - J Alberto Marco
- Depart. de Q. Orgánica, Univ. de Valencia, E-46100 Burjassot, Valencia, Spain
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586
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Zhang Z, Nishimura Y, Kanchanawong P. Extracting microtubule networks from superresolution single-molecule localization microscopy data. Mol Biol Cell 2016; 28:333-345. [PMID: 27852898 PMCID: PMC5231901 DOI: 10.1091/mbc.e16-06-0421] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 11/07/2016] [Accepted: 11/10/2016] [Indexed: 12/05/2022] Open
Abstract
Microtubule filaments form ubiquitous networks. However, quantitative analysis of this structure is difficult due to its complex architecture. A tool is given for the automated retrieval of microtubule filaments from superresolution microscopy images and used for a quantitative analysis of microtubule network architecture phenotypes in fibroblasts. Microtubule filaments form ubiquitous networks that specify spatial organization in cells. However, quantitative analysis of microtubule networks is hampered by their complex architecture, limiting insights into the interplay between their organization and cellular functions. Although superresolution microscopy has greatly facilitated high-resolution imaging of microtubule filaments, extraction of complete filament networks from such data sets is challenging. Here we describe a computational tool for automated retrieval of microtubule filaments from single-molecule-localization–based superresolution microscopy images. We present a user-friendly, graphically interfaced implementation and a quantitative analysis of microtubule network architecture phenotypes in fibroblasts.
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Affiliation(s)
- Zhen Zhang
- Mechanobiology Institute, National University of Singapore, 117411 Singapore
| | - Yukako Nishimura
- Mechanobiology Institute, National University of Singapore, 117411 Singapore
| | - Pakorn Kanchanawong
- Mechanobiology Institute, National University of Singapore, 117411 Singapore .,Department of Biomedical Engineering, National University of Singapore, 117411 Singapore
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587
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Dugina V, Alieva I, Khromova N, Kireev I, Gunning PW, Kopnin P. Interaction of microtubules with the actin cytoskeleton via cross-talk of EB1-containing +TIPs and γ-actin in epithelial cells. Oncotarget 2016; 7:72699-72715. [PMID: 27683037 PMCID: PMC5341938 DOI: 10.18632/oncotarget.12236] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Accepted: 09/18/2016] [Indexed: 12/16/2022] Open
Abstract
Actin microfilaments and microtubules are both highly dynamic cytoskeleton components implicated in a wide range of intracellular processes as well as cell-cell and cell-substrate interactions. The interactions of actin filaments with the microtubule system play an important role in the assembly and maintenance of 3D cell structure. Here we demonstrate that cytoplasmic actins are differentially distributed in relation to the microtubule system. LSM, 3D-SIM, proximity ligation assay (PLA) and co-immunoprecipitation methods applied in combination with selective depletion of β- or γ-cytoplasmic actins revealed a selective interaction between microtubules and γ-, but not β-cytoplasmic actin via the microtubule +TIPs protein EB1. EB1-positive comet distribution analysis and quantification have shown more effective microtubule growth in the absence of β-actin. Our data represent the first demonstration that microtubule +TIPs protein EB1 interacts mainly with γ-cytoplasmic actin in epithelial cells.
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Affiliation(s)
- Vera Dugina
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
- School of Medical Science, The University of New South Wales, NSW, Sydney, Australia
| | - Irina Alieva
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
- School of Medical Science, The University of New South Wales, NSW, Sydney, Australia
| | | | - Igor Kireev
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Peter W. Gunning
- School of Medical Science, The University of New South Wales, NSW, Sydney, Australia
| | - Pavel Kopnin
- Blokhin Russian Cancer Research Center, Moscow, Russia
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588
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EML proteins in microtubule regulation and human disease. Biochem Soc Trans 2016; 44:1281-1288. [DOI: 10.1042/bst20160125] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Revised: 06/14/2016] [Accepted: 06/15/2016] [Indexed: 11/17/2022]
Abstract
The EMLs are a conserved family of microtubule-associated proteins (MAPs). The founding member was discovered in sea urchins as a 77-kDa polypeptide that co-purified with microtubules. This protein, termed EMAP for echinoderm MAP, was the major non-tubulin component present in purified microtubule preparations made from unfertilized sea urchin eggs [J. Cell Sci. (1993) 104, 445–450; J. Cell Sci. (1987) 87(Pt 1), 71–84]. Orthologues of EMAP were subsequently identified in other echinoderms, such as starfish and sand dollar, and then in more distant eukaryotes, including flies, worms and vertebrates, where the name of ELP or EML (both for EMAP-like protein) has been adopted [BMC Dev. Biol. (2008) 8, 110; Dev. Genes Evol. (2000) 210, 2–10]. The common property of these proteins is their ability to decorate microtubules. However, whether they are associated with particular microtubule populations or exercise specific functions in different microtubule-dependent processes remains unknown. Furthermore, although there is limited evidence that they regulate microtubule dynamics, the biochemical mechanisms of their molecular activity have yet to be explored. Nevertheless, interest in these proteins has grown substantially because of the identification of EML mutations in neuronal disorders and oncogenic fusions in human cancers. Here, we summarize our current knowledge of the expression, localization and structure of what is proving to be an interesting and important class of MAPs. We also speculate about their function in microtubule regulation and highlight how the studies of EMLs in human diseases may open up novel avenues for patient therapy.
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589
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Bates D, Eastman A. Microtubule destabilising agents: far more than just antimitotic anticancer drugs. Br J Clin Pharmacol 2016; 83:255-268. [PMID: 27620987 DOI: 10.1111/bcp.13126] [Citation(s) in RCA: 202] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Revised: 08/11/2016] [Accepted: 09/07/2016] [Indexed: 02/06/2023] Open
Abstract
Vinca alkaloids have been approved as anticancer drugs for more than 50 years. They have been classified as cytotoxic chemotherapy drugs that act during cellular mitosis, enabling them to target fast growing cancer cells. With the evolution of cancer drug development there has been a shift towards new "targeted" therapies to avoid the side effects and general toxicities of "cytotoxic chemotherapies" such as the vinca alkaloids. Due to their original classification, many have overlooked the fact that vinca alkaloids, taxanes and related drugs do have a specific molecular target: tubulin. They continue to be some of the most effective anticancer drugs, perhaps because their actions upon the microtubule network extend far beyond the ability to halt cells in mitosis, and include the induction of apoptosis at all phases of the cell cycle. In this review, we highlight the numerous cellular consequences of disrupting microtubule dynamics, expanding the textbook knowledge of microtubule destabilising agents and providing novel opportunities for their use in cancer therapy.
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Affiliation(s)
- Darcy Bates
- Department of Medicine, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire
| | - Alan Eastman
- Norris Cotton Cancer Center, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire
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590
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Dynamics of nanoparticle diffusion and uptake in three-dimensional cell cultures. Colloids Surf B Biointerfaces 2016; 149:7-15. [PMID: 27710850 DOI: 10.1016/j.colsurfb.2016.09.046] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2016] [Revised: 09/14/2016] [Accepted: 09/29/2016] [Indexed: 11/21/2022]
Abstract
This study aims at elucidating the effect of three-dimensional (3D) extracellular matrix on cell behaviour and nanoparticle (NP) diffusion and its consequences on NP cellular uptake mechansims. For this purpose, human dermal fibroblasts (HDF) and human fibrosarcoma (HT1080) cell lines were grown within a 3D collagen gel and exposed to model polystyrene (PS) NPs of controlled size (44 and 100nm). Results indicate that, in 3D, cell morphology dramatically changes compared to standard 2D cultures and NP diffusion within the matrix is hampered by the interaction with the collagen fibres. As a consequence, NP cellular uptake, modeled with equations describing the stoichiometric exchange between NPs and cell membrane, is significantly slowed down in 3D and in the case of 100 nm NPs, in part due to the hampered diffusion of NPs in collagen gel compared to their transport in standard cell culture medium. Furthermore, our outcomes point at a significant contribution of the cytoskeleton assembly, in particular actin microfilaments, in governing the uptake of PS NPs in a 3D environment, and also that the macropinocytosis process is preserved and is mainly involved in the internalization of PS NPs in a 3D environment. However, depending on cell type and nanoparticle size, other endocytic pathways are also implicated when moving from 2D to 3D culture systems. This work highlights the importance of studying the nano-bio interaction in experimental models that resembles in vivo conditions in order to better predict the therapeutic efficacy of drug delivery systems.
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591
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Voelzmann A, Hahn I, Pearce SP, Sánchez-Soriano N, Prokop A. A conceptual view at microtubule plus end dynamics in neuronal axons. Brain Res Bull 2016; 126:226-237. [PMID: 27530065 PMCID: PMC5090033 DOI: 10.1016/j.brainresbull.2016.08.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Revised: 08/08/2016] [Accepted: 08/11/2016] [Indexed: 12/02/2022]
Abstract
Axons are the cable-like protrusions of neurons which wire up the nervous system. Polar bundles of microtubules (MTs) constitute their structural backbones and are highways for life-sustaining transport between proximal cell bodies and distal synapses. Any morphogenetic changes of axons during development, plastic rearrangement, regeneration or degeneration depend on dynamic changes of these MT bundles. A key mechanism for implementing such changes is the coordinated polymerisation and depolymerisation at the plus ends of MTs within these bundles. To gain an understanding of how such regulation can be achieved at the cellular level, we provide here an integrated overview of the extensive knowledge we have about the molecular mechanisms regulating MT de/polymerisation. We first summarise insights gained from work in vitro, then describe the machinery which supplies the essential tubulin building blocks, the protein complexes associating with MT plus ends, and MT shaft-based mechanisms that influence plus end dynamics. We briefly summarise the contribution of MT plus end dynamics to important cellular functions in axons, and conclude by discussing the challenges and potential strategies of integrating the existing molecular knowledge into conceptual understanding at the level of axons.
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Affiliation(s)
- André Voelzmann
- The University of Manchester, Faculty of Biology, Medicine and Health, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
| | - Ines Hahn
- The University of Manchester, Faculty of Biology, Medicine and Health, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
| | - Simon P Pearce
- The University of Manchester, Faculty of Biology, Medicine and Health, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK; The University of Manchester, School of Mathematics, Alan Turing Building, Oxford Road, Manchester M13 9PL, UK
| | - Natalia Sánchez-Soriano
- University of Liverpool, Institute of Translational Medicine, Department of Cellular and Molecular Physiology, Crown Street, Liverpool, L69 3BX, UK
| | - Andreas Prokop
- The University of Manchester, Faculty of Biology, Medicine and Health, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK.
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592
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Baas PW, Rao AN, Matamoros AJ, Leo L. Stability properties of neuronal microtubules. Cytoskeleton (Hoboken) 2016; 73:442-60. [PMID: 26887570 PMCID: PMC5541393 DOI: 10.1002/cm.21286] [Citation(s) in RCA: 184] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Revised: 02/02/2016] [Accepted: 02/12/2016] [Indexed: 01/12/2023]
Abstract
Neurons are terminally differentiated cells that use their microtubule arrays not for cell division but rather as architectural elements required for the elaboration of elongated axons and dendrites. In addition to acting as compression-bearing struts that provide for the shape of the neuron, microtubules also act as directional railways for organelle transport. The stability properties of neuronal microtubules are commonly discussed in the biomedical literature as crucial to the development and maintenance of the nervous system, and have recently gained attention as central to the etiology of neurodegenerative diseases. Drugs that affect microtubule stability are currently under investigation as potential therapies for disease and injury of the nervous system. There is often a lack of consistency, however, in how the issue of microtubule stability is discussed in the literature, and this can affect the design and interpretation of experiments as well as potential therapeutic regimens. Neuronal microtubules are considered to be more stable than microtubules in dividing cells. On average, this is true, but in addition to an abundant stable microtubule fraction in neurons, there is also an abundant labile microtubule fraction. Both are functionally important. Individual microtubules consist of domains that differ in their stability properties, and these domains can also differ markedly in their composition as well as how they interact with various microtubule-related proteins in the neuron. Myriad proteins and pathways have been discussed as potential contributors to microtubule stability in neurons. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Peter W Baas
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA.
| | - Anand N Rao
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - Andrew J Matamoros
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - Lanfranco Leo
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
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593
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Insights into the process of EB1-dependent tip-tracking of kinesin-14 Ncd. The role of the microtubule. Eur J Cell Biol 2016; 95:521-530. [PMID: 27608966 DOI: 10.1016/j.ejcb.2016.08.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 08/11/2016] [Accepted: 08/29/2016] [Indexed: 01/13/2023] Open
Abstract
End-binding proteins are capable of tracking the plus-ends of growing microtubules (MTs). The motor protein Ncd, a member of the kinesin-14 family, interacts with EB1 protein and becomes a non-autonomous tip-tracker. Here, we attempted to find out whether at least for Ncd, the efficient EB1-mediated tip-tracking involves the interaction of the kinesin with the MT surface. We prepared a series of Ncd tail mutants in which the MT-binding sites were altered or eliminated. Using TIRF microscopy, we characterized their behavior as tip-trackers and measured the dwell times of single molecules of EB1 and Ncd tail or its mutated forms. The mutated forms of Ncd tail exhibited tip-tracking in the presence of EB1 and the effectiveness of this process was proportional to the affinity of the mutant's tail to MT. Even though the interaction of Ncd with EB1 was weak (Kd∼9μM) the half saturating concentration of EB1 for tip-tracking was 7nM. The dwell time of Ncd tail in the presence of EB1 was ∼1s. The dwell time of EB1 alone was shorter (∼0.3s) and increased considerably in the presence of a large excess of Ncd tail. We demonstrated that tip-tracking of kinesin-14 occurs through several concurrent mechanisms: binding of kinesin only to EB1 located at the MT end, interaction of the kinesin molecules with a composite site formed by EB1 and the MT tip, and probably surface diffusion of the tail along MT. The second mechanism seems to play a crucial role in efficient tip-tracking.
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594
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Kent IA, Lele TP. Microtubule-based force generation. WILEY INTERDISCIPLINARY REVIEWS-NANOMEDICINE AND NANOBIOTECHNOLOGY 2016; 9. [PMID: 27562344 DOI: 10.1002/wnan.1428] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 07/20/2016] [Accepted: 07/30/2016] [Indexed: 11/11/2022]
Abstract
Microtubules are vital to many important cell processes, such as cell division, transport of cellular cargo, organelle positioning, and cell migration. Owing to their diverse functions, understanding microtubule function is an important part of cell biological research that can help in combating various diseases. For example, microtubules are an important target of chemotherapeutic drugs such as paclitaxel because of their pivotal role in cell division. Many functions of microtubules relate to the generation of mechanical forces. These forces are generally either a direct result of microtubule polymerization/depolymerization or generated by motor proteins that move processively along microtubules. In this review, we summarize recent efforts to quantify and model force generation by microtubules in the context of microtubule function. WIREs Nanomed Nanobiotechnol 2017, 9:e1428. doi: 10.1002/wnan.1428 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Ian A Kent
- Department of Chemical Engineering, University of Florida, Gainesville, FL, USA
| | - Tanmay P Lele
- Department of Chemical Engineering, University of Florida, Gainesville, FL, USA
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595
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Duellberg C, Cade NI, Surrey T. Microtubule aging probed by microfluidics-assisted tubulin washout. Mol Biol Cell 2016; 27:3563-3573. [PMID: 27489342 PMCID: PMC5221588 DOI: 10.1091/mbc.e16-07-0548] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Accepted: 07/28/2016] [Indexed: 11/24/2022] Open
Abstract
Microtubule aging—the decrease of stability with age—is an interesting but mechanistically not understood property of microtubules. It constrains possible mechanisms of catastrophe induction and is believed to be crucial for length regulation. New in vitro experiments and model fits provide insight into the origin of microtubule aging. Microtubules switch stochastically between phases of growth and shrinkage. The molecular mechanism responsible for the end of a growth phase, an event called catastrophe, is still not understood. The probability for a catastrophe to occur increases with microtubule age, putting constraints on the possible molecular mechanism of catastrophe induction. Here we used microfluidics-assisted fast tubulin washout experiments to induce microtubule depolymerization in a controlled manner at different times after the start of growth. We found that aging can also be observed in this assay, providing valuable new constraints against which theoretical models of catastrophe induction can be tested. We found that the data can be quantitatively well explained by a simple kinetic threshold model that assumes an age-dependent broadening of the protective cap at the microtubule end as a result of an evolving tapered end structure; this leads to a decrease of the cap density and its stability. This analysis suggests an intuitive picture of the role of morphological changes of the protective cap for the age dependence of microtubule stability.
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Affiliation(s)
- Christian Duellberg
- Lincoln's Inn Fields Laboratory, Francis Crick Institute, London WC2A 3LY, United Kingdom
| | - Nicholas Ian Cade
- Lincoln's Inn Fields Laboratory, Francis Crick Institute, London WC2A 3LY, United Kingdom
| | - Thomas Surrey
- Lincoln's Inn Fields Laboratory, Francis Crick Institute, London WC2A 3LY, United Kingdom
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596
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Hori A, Toda T. Regulation of centriolar satellite integrity and its physiology. Cell Mol Life Sci 2016; 74:213-229. [PMID: 27484406 PMCID: PMC5219025 DOI: 10.1007/s00018-016-2315-x] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Revised: 07/14/2016] [Accepted: 07/21/2016] [Indexed: 01/01/2023]
Abstract
Centriolar satellites comprise cytoplasmic granules that are located around the centrosome. Their molecular identification was first reported more than a quarter of a century ago. These particles are not static in the cell but instead constantly move around the centrosome. Over the last decade, significant advances in their molecular compositions and biological functions have been achieved due to comprehensive proteomics and genomics, super-resolution microscopy analyses and elegant genetic manipulations. Centriolar satellites play pivotal roles in centrosome assembly and primary cilium formation through the delivery of centriolar/centrosomal components from the cytoplasm to the centrosome. Their importance is further underscored by the fact that mutations in genes encoding satellite components and regulators lead to various human disorders such as ciliopathies. Moreover, the most recent findings highlight dynamic structural remodelling in response to internal and external cues and unexpected positive feedback control that is exerted from the centrosome for centriolar satellite integrity.
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Affiliation(s)
- Akiko Hori
- Lincoln's Inn Fields Laboratory, The Francis Crick Institute, 44 Lincoln's Inn Fields, London, WC2A 3LY, UK.,Developmental Biomedical Science, Graduate School of Biological Sciences, Nara Institute of Science and Technology (NAIST), 8916-5 Takayama, Ikoma, Nara, 630-0192, Japan
| | - Takashi Toda
- Lincoln's Inn Fields Laboratory, The Francis Crick Institute, 44 Lincoln's Inn Fields, London, WC2A 3LY, UK. .,Department of Molecular Biotechnology, Hiroshima Research Center for Healthy Aging (HiHA), Graduate School of Advanced Sciences of Matter, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, 739-8530, Japan.
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597
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Tao J, Feng C, Rolls MM. The microtubule-severing protein fidgetin acts after dendrite injury to promote their degeneration. J Cell Sci 2016; 129:3274-81. [PMID: 27411367 DOI: 10.1242/jcs.188540] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Accepted: 07/08/2016] [Indexed: 02/01/2023] Open
Abstract
After being severed from the cell body, axons initiate an active degeneration program known as Wallerian degeneration. Although dendrites also seem to have an active injury-induced degeneration program, no endogenous regulators of this process are known. Because microtubule disassembly has been proposed to play a role in both pruning and injury-induced degeneration, we used a Drosophila model to identify microtubule regulators involved in dendrite degeneration. We found that, when levels of fidgetin were reduced using mutant or RNA interference (RNAi) strategies, dendrite degeneration was delayed, but axon degeneration and dendrite pruning proceeded with normal timing. We explored two possible ways in which fidgetin could promote dendrite degeneration: (1) by acting constitutively to moderate microtubule stability in dendrites, or (2) by acting specifically after injury to disassemble microtubules. When comparing microtubule dynamics and stability in uninjured neurons with and without fidgetin, we could not find evidence that fidgetin regulated microtubule stability constitutively. However, we identified a fidgetin-dependent increase in microtubule dynamics in severed dendrites. We conclude that fidgetin acts after injury to promote disassembly of microtubules in dendrites severed from the cell body.
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Affiliation(s)
- Juan Tao
- Department of Biochemistry and Molecular Biology and The Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA 16802, USA
| | - Chengye Feng
- Department of Biochemistry and Molecular Biology and The Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA 16802, USA
| | - Melissa M Rolls
- Department of Biochemistry and Molecular Biology and The Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA 16802, USA
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598
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Li N, Mruk DD, Tang EI, Lee WM, Wong CKC, Cheng CY. Formin 1 Regulates Microtubule and F-Actin Organization to Support Spermatid Transport During Spermatogenesis in the Rat Testis. Endocrinology 2016; 157:2894-908. [PMID: 27145014 PMCID: PMC4929546 DOI: 10.1210/en.2016-1133] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Formin 1 confers actin nucleation by generating long stretches of actin microfilaments to support cell movement, cell shape, and intracellular protein trafficking. Formin 1 is likely involved in microtubule (MT) dynamics due to the presence of a MT binding domain near its N terminus. Here, formin 1 was shown to structurally interact with α-tubulin, the building block of MT, and also end-binding protein 1 (a MT plus [+]-end-binding protein that stabilizes MT) in the testis. Knockdown of formin 1 in Sertoli cells with an established tight junction barrier was found to induce down-regulation of detyrosinated MT (a stabilized form of MT), and disorganization of MTs, in which MTs were retracted from the cell cortical zone, mediated through a loss of MT polymerization and down-regulation of Akt1/2 signaling kinase. An efficient knockdown of formin 1 in the testis reduced the number of track-like structures conferred by MTs and F-actin considerably, causing defects in spermatid and phagosome transport across the seminiferous epithelium. In summary, formin1 maintains MT and F-actin track-like structures to support spermatid and phagosome transport across the seminiferous epithelium during spermatogenesis.
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Affiliation(s)
- Nan Li
- The Mary M. Wohlford Laboratory for Male Contraceptive Research (N.L., D.D.M., E.I.T., C.Y.C.), Center for Biomedical Research, Population Council, New York, New York 10065-6307; College of Life Sciences and Oceanography (N.L.), Shenzhen University, Shenzhen 518060, China; School of Biological Sciences (W.M.L.), University of Hong Kong, Hong Kong, China; and Department of Biology (C.K.C.W.), Hong Kong Baptist University, Hong Kong, China
| | - Dolores D Mruk
- The Mary M. Wohlford Laboratory for Male Contraceptive Research (N.L., D.D.M., E.I.T., C.Y.C.), Center for Biomedical Research, Population Council, New York, New York 10065-6307; College of Life Sciences and Oceanography (N.L.), Shenzhen University, Shenzhen 518060, China; School of Biological Sciences (W.M.L.), University of Hong Kong, Hong Kong, China; and Department of Biology (C.K.C.W.), Hong Kong Baptist University, Hong Kong, China
| | - Elizabeth I Tang
- The Mary M. Wohlford Laboratory for Male Contraceptive Research (N.L., D.D.M., E.I.T., C.Y.C.), Center for Biomedical Research, Population Council, New York, New York 10065-6307; College of Life Sciences and Oceanography (N.L.), Shenzhen University, Shenzhen 518060, China; School of Biological Sciences (W.M.L.), University of Hong Kong, Hong Kong, China; and Department of Biology (C.K.C.W.), Hong Kong Baptist University, Hong Kong, China
| | - Will M Lee
- The Mary M. Wohlford Laboratory for Male Contraceptive Research (N.L., D.D.M., E.I.T., C.Y.C.), Center for Biomedical Research, Population Council, New York, New York 10065-6307; College of Life Sciences and Oceanography (N.L.), Shenzhen University, Shenzhen 518060, China; School of Biological Sciences (W.M.L.), University of Hong Kong, Hong Kong, China; and Department of Biology (C.K.C.W.), Hong Kong Baptist University, Hong Kong, China
| | - Chris K C Wong
- The Mary M. Wohlford Laboratory for Male Contraceptive Research (N.L., D.D.M., E.I.T., C.Y.C.), Center for Biomedical Research, Population Council, New York, New York 10065-6307; College of Life Sciences and Oceanography (N.L.), Shenzhen University, Shenzhen 518060, China; School of Biological Sciences (W.M.L.), University of Hong Kong, Hong Kong, China; and Department of Biology (C.K.C.W.), Hong Kong Baptist University, Hong Kong, China
| | - C Yan Cheng
- The Mary M. Wohlford Laboratory for Male Contraceptive Research (N.L., D.D.M., E.I.T., C.Y.C.), Center for Biomedical Research, Population Council, New York, New York 10065-6307; College of Life Sciences and Oceanography (N.L.), Shenzhen University, Shenzhen 518060, China; School of Biological Sciences (W.M.L.), University of Hong Kong, Hong Kong, China; and Department of Biology (C.K.C.W.), Hong Kong Baptist University, Hong Kong, China
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599
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Pérez-Pérez MJ, Priego EM, Bueno O, Martins MS, Canela MD, Liekens S. Blocking Blood Flow to Solid Tumors by Destabilizing Tubulin: An Approach to Targeting Tumor Growth. J Med Chem 2016; 59:8685-8711. [DOI: 10.1021/acs.jmedchem.6b00463] [Citation(s) in RCA: 121] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
| | - Eva-María Priego
- Instituto de Química Médica (IQM-CSIC), Juan de la Cierva 3, E-28006 Madrid, Spain
| | - Oskía Bueno
- Instituto de Química Médica (IQM-CSIC), Juan de la Cierva 3, E-28006 Madrid, Spain
| | | | - María-Dolores Canela
- Instituto de Química Médica (IQM-CSIC), Juan de la Cierva 3, E-28006 Madrid, Spain
| | - Sandra Liekens
- Rega
Institute for Medical Research, KU Leuven, B-3000 Leuven, Belgium
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600
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Parrish AR. The cytoskeleton as a novel target for treatment of renal fibrosis. Pharmacol Ther 2016; 166:1-8. [PMID: 27343756 DOI: 10.1016/j.pharmthera.2016.06.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Accepted: 06/07/2016] [Indexed: 12/23/2022]
Abstract
The incidence of chronic kidney disease (CKD) is increasing, with an estimated prevalence of 12% in the United States (Synder et al., 2009). While CKD may progress to end-stage renal disease (ESRD), which necessitates renal replacement therapy, i.e. dialysis or transplantation, most CKD patients never reach ESRD due to the increased risk of death from cardiovascular disease. It is well-established that regardless of the initiating insult - most often diabetes or hypertension - fibrosis is the common pathogenic pathway that leads to progressive injury and organ dysfunction (Eddy, 2014; Duffield, 2014). As such, there has been extensive research into the molecular and cellular mechanisms of renal fibrosis; however, translation to effective therapeutic strategies has been limited. While a role for the disruption of the cytoskeleton, most notably the actin network, has been established in acute kidney injury over the past two decades, a role in regulating renal fibrosis and CKD is only recently emerging. This review will focus on the role of the cytoskeleton in regulating pro-fibrotic pathways in the kidney, as well as data suggesting that these pathways represent novel therapeutic targets to manage fibrosis and ultimately CKD.
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Affiliation(s)
- Alan R Parrish
- Department of Medical Pharmacology and Physiology, School of Medicine, University of Missouri, Columbia, MO 65212, USA.
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