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Scrofani J, Ruhnow F, Chew WX, Normanno D, Nedelec F, Surrey T, Vernos I. Branched microtubule nucleation and dynein transport organize RanGTP asters in Xenopus laevis egg extract. Mol Biol Cell 2024; 35:ar12. [PMID: 37991893 PMCID: PMC10881172 DOI: 10.1091/mbc.e23-10-0407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 11/03/2023] [Accepted: 11/07/2023] [Indexed: 11/24/2023] Open
Abstract
Chromosome segregation relies on the correct assembly of a bipolar spindle. Spindle pole self-organization requires dynein-dependent microtubule (MT) transport along other MTs. However, during M-phase RanGTP triggers MT nucleation and branching generating polarized arrays with nonastral organization in which MT minus ends are linked to the sides of other MTs. This raises the question of how branched-MT nucleation and dynein-mediated transport cooperate to organize the spindle poles. Here, we used RanGTP-dependent MT aster formation in Xenopus laevis (X. laevis) egg extract to study the interplay between these two seemingly conflicting organizing principles. Using temporally controlled perturbations of MT nucleation and dynein activity, we found that branched MTs are not static but instead dynamically redistribute over time as poles self-organize. Our experimental data together with computer simulations suggest a model where dynein together with dynactin and NuMA directly pulls and move branched MT minus ends toward other MT minus ends.
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Affiliation(s)
- Jacopo Scrofani
- Quantitative Cell Biology Program, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, 08003 Barcelona, Spain
| | - Felix Ruhnow
- Quantitative Cell Biology Program, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, 08003 Barcelona, Spain
| | - Wei-Xiang Chew
- Quantitative Cell Biology Program, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, 08003 Barcelona, Spain
| | - Davide Normanno
- Quantitative Cell Biology Program, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, 08003 Barcelona, Spain
| | - Francois Nedelec
- Sainsbury Laboratory, Cambridge University, Bateman street, CB2 1LR Cambridge, UK
| | - Thomas Surrey
- Quantitative Cell Biology Program, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, 08003 Barcelona, Spain
- Universitat Pompeu Fabra (UPF), 08002 Barcelona, Spain
- Institución Catalana de Investigación y Estudios Avanzados (ICREA), Pg. Lluis Companys 23, 08010 Barcelona, Spain
| | - Isabelle Vernos
- Quantitative Cell Biology Program, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, 08003 Barcelona, Spain
- Universitat Pompeu Fabra (UPF), 08002 Barcelona, Spain
- Institución Catalana de Investigación y Estudios Avanzados (ICREA), Pg. Lluis Companys 23, 08010 Barcelona, Spain
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2
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Zhovmer AS, Manning A, Smith C, Hayes JB, Burnette DT, Wang J, Cartagena-Rivera AX, Dokholyan NV, Singh RK, Tabdanov ED. Mechanical Counterbalance of Kinesin and Dynein Motors in a Microtubular Network Regulates Cell Mechanics, 3D Architecture, and Mechanosensing. ACS NANO 2021; 15:17528-17548. [PMID: 34677937 PMCID: PMC9291236 DOI: 10.1021/acsnano.1c04435] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Microtubules (MTs) and MT motor proteins form active 3D networks made of unstretchable cables with rod-like bending mechanics that provide cells with a dynamically changing structural scaffold. In this study, we report an antagonistic mechanical balance within the dynein-kinesin microtubular motor system. Dynein activity drives the microtubular network inward compaction, while isolated activity of kinesins bundles and expands MTs into giant circular bands that deform the cell cortex into discoids. Furthermore, we show that dyneins recruit MTs to sites of cell adhesion, increasing the topographic contact guidance of cells, while kinesins antagonize it via retraction of MTs from sites of cell adhesion. Actin-to-microtubule translocation of septin-9 enhances kinesin-MT interactions, outbalances the activity of kinesins over that of dyneins, and induces the discoid architecture of cells. These orthogonal mechanisms of MT network reorganization highlight the existence of an intricate mechanical balance between motor activities of kinesins and dyneins that controls cell 3D architecture, mechanics, and cell-microenvironment interactions.
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Affiliation(s)
- Alexander S. Zhovmer
- Center
for Biologics Evaluation and Research, U.S.
Food and Drug Administration, Silver Spring, Maryland 20903, United States
| | - Alexis Manning
- Center
for Biologics Evaluation and Research, U.S.
Food and Drug Administration, Silver Spring, Maryland 20903, United States
| | - Chynna Smith
- Section
on Mechanobiology, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - James B. Hayes
- Department
of Cell and Developmental Biology, Vanderbilt Medical Center, University of Vanderbilt, Nashville, Tennessee 37232, United States
| | - Dylan T. Burnette
- Department
of Cell and Developmental Biology, Vanderbilt Medical Center, University of Vanderbilt, Nashville, Tennessee 37232, United States
| | - Jian Wang
- Department
of Pharmacology, Penn State College of Medicine, Pennsylvania State University, Hummelstown, Pennsylvania 17036, United States
| | - Alexander X. Cartagena-Rivera
- Section
on Mechanobiology, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Nikolay V. Dokholyan
- Department
of Pharmacology, Penn State College of Medicine, Pennsylvania State University, Hummelstown, Pennsylvania 17036, United States
- Department
of Biochemistry & Molecular Biology, Penn State College of Medicine, Pennsylvania State University, Hershey, Pennsylvania 17033, United States
| | - Rakesh K. Singh
- Department
of Obstetrics and Gynecology, University
of Rochester Medical Center, Rochester, New York 14620, United States
| | - Erdem D. Tabdanov
- Department
of Pharmacology, Penn State College of Medicine, Pennsylvania State University, Hummelstown, Pennsylvania 17036, United States
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3
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Ndel1 and Reelin Maintain Postnatal CA1 Hippocampus Integrity. J Neurosci 2017; 36:6538-52. [PMID: 27307241 DOI: 10.1523/jneurosci.2869-15.2016] [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: 07/29/2015] [Accepted: 05/04/2016] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED How the integrity of laminar structures in the postnatal brain is maintained impacts neuronal functions. Ndel1, the mammalian homolog of NuDE from the filamentous fungus Aspergillus nidulans, is an atypical microtubule (MT)-associated protein that was initially investigated in the contexts of neurogenesis and neuronal migration. Constitutive knock-out mice for Ndel1 are embryonic lethal, thereby necessitating the creation a conditional knock-out to probe the roles of Ndel1 in postnatal brains. Here we report that CA1 pyramidal neurons from mice postnatally lacking Ndel1 (Ndel1 conditional knock-out) exhibit fragmented MTs, dendritic/synaptic pathologies, are intrinsically hyperexcitable and undergo dispersion independently of neuronal migration defect. Secondary to the pyramidal cell changes is the decreased inhibitory drive onto pyramidal cells from interneurons. Levels of the glycoprotein Reelin that regulates MTs, neuronal plasticity, and cell compaction are significantly reduced in hippocampus of mutant mice. Strikingly, a single injection of Reelin into the hippocampus of Ndel1 conditional knock-out mice ameliorates ultrastructural, cellular, morphological, and anatomical CA1 defects. Thus, Ndel1 and Reelin contribute to maintain postnatal CA1 integrity. SIGNIFICANCE STATEMENT The significance of this study rests in the elucidation of a role for Nde1l and Reelin in postnatal CA1 integrity using a new conditional knock-out mouse model for the cytoskeletal protein Ndel1, one that circumvents the defects associated with neuronal migration and embryonic lethality. Our study serves as a basis for understanding the mechanisms underlying postnatal hippocampal maintenance and function, and the significance of decreased levels of Ndel1 and Reelin observed in patients with neurological disorders.
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4
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Mahale S, Kumar M, Sharma A, Babu A, Ranjan S, Sachidanandan C, Mylavarapu SVS. The Light Intermediate Chain 2 Subpopulation of Dynein Regulates Mitotic Spindle Orientation. Sci Rep 2016; 6:22. [PMID: 28003657 PMCID: PMC5431351 DOI: 10.1038/s41598-016-0030-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 11/03/2016] [Indexed: 12/11/2022] Open
Abstract
Cytoplasmic dynein 1 is a multi-protein intracellular motor essential for mediating several mitotic functions, including the establishment of proper spindle orientation. The functional relevance and mechanistic distinctions between two discrete dynein subpopulations distinguished only by Light Intermediate Chain (LIC) homologues, LIC1 and LIC2 is unknown during mitosis. Here, we identify LIC2-dynein as the major mediator of proper spindle orientation and uncover its underlying molecular mechanism. Cortically localized dynein, essential for maintaining correct spindle orientation, consists majorly of LIC2-dynein, which interacts with cortical 14-3-3 ε- ζ and Par3, conserved proteins required for orienting the spindle. LIC2-dynein is also responsible for the majority of dynein-mediated asymmetric poleward transport of NuMA, helping focus microtubule minus ends. In addition, LIC2-dynein dominates in equatorially aligning chromosomes at metaphase and in regulating mitotic spindle length. Key mitotic functions of LIC2 were remarkably conserved in and essential for early embryonic divisions and development in zebrafish. Thus LIC2-dynein exclusively engages with two major cortical pathways to govern spindle orientation. Overall, we identify a novel selectivity of molecular interactions between the two LICs in mitosis as the underlying basis for their uneven distribution of labour in ensuring proper spindle orientation.
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Affiliation(s)
- Sagar Mahale
- Laboratory of Cellular Dynamics, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad, Haryana, 121001, India.,Affiliated to Manipal University, Manipal, Karnataka, 576104, India
| | - Megha Kumar
- Laboratory of Cellular Dynamics, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad, Haryana, 121001, India
| | - Amit Sharma
- Laboratory of Cellular Dynamics, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad, Haryana, 121001, India.,Affiliated to Manipal University, Manipal, Karnataka, 576104, India
| | - Aswini Babu
- CSIR-Institute of Genomics & Integrative Biology, South Campus, New Delhi, 110025, India.,Academy of Scientific and Innovative Research (AcSIR), New Delhi, 110025, India
| | - Shashi Ranjan
- CSIR-Institute of Genomics & Integrative Biology, South Campus, New Delhi, 110025, India
| | - Chetana Sachidanandan
- CSIR-Institute of Genomics & Integrative Biology, South Campus, New Delhi, 110025, India.,Academy of Scientific and Innovative Research (AcSIR), New Delhi, 110025, India
| | - Sivaram V S Mylavarapu
- Laboratory of Cellular Dynamics, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad, Haryana, 121001, India. .,Affiliated to Manipal University, Manipal, Karnataka, 576104, India.
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5
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Rezaul K, Gupta D, Semenova I, Ikeda K, Kraikivski P, Yu J, Cowan A, Zaliapin I, Rodionov V. Engineered Tug-of-War Between Kinesin and Dynein Controls Direction of Microtubule Based Transport In Vivo. Traffic 2016; 17:475-86. [PMID: 26843027 DOI: 10.1111/tra.12385] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 02/01/2016] [Accepted: 02/01/2016] [Indexed: 01/19/2023]
Abstract
Bidirectional transport of membrane organelles along microtubules (MTs) is driven by plus-end directed kinesins and minus-end directed dynein bound to the same cargo. Activities of opposing MT motors produce bidirectional movement of membrane organelles and cytoplasmic particles along MT transport tracks. Directionality of MT-based transport might be controlled by a protein complex that determines which motor type is active at any given moment of time, or determined by the outcome of a tug-of-war between MT motors dragging cargo organelles in opposite directions. However, evidence in support of each mechanisms of regulation is based mostly on the results of theoretical analyses or indirect experimental data. Here, we test whether the direction of movement of membrane organelles in vivo can be controlled by the tug-of-war between opposing MT motors alone, by attaching a large number of kinesin-1 motors to organelles transported by dynein to minus-ends of MTs. We find that recruitment of kinesin significantly reduces the length and velocity of minus-end-directed dynein-dependent MT runs, leading to a reversal of the overall direction of dynein-driven organelles in vivo. Therefore, in the absence of external regulators tug-of-war between opposing MT motors alone is sufficient to determine the directionality of MT transport in vivo.
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Affiliation(s)
- Karim Rezaul
- R.D.Berlin Center for Cell Analysis and Modeling, and Department of Cell Biology, UConn Health, 400 Farmington Avenue, Farmington, CT 06030-6406, USA
| | - Dipika Gupta
- R.D.Berlin Center for Cell Analysis and Modeling, and Department of Cell Biology, UConn Health, 400 Farmington Avenue, Farmington, CT 06030-6406, USA
| | - Irina Semenova
- R.D.Berlin Center for Cell Analysis and Modeling, and Department of Cell Biology, UConn Health, 400 Farmington Avenue, Farmington, CT 06030-6406, USA
| | - Kazuho Ikeda
- R.D.Berlin Center for Cell Analysis and Modeling, and Department of Cell Biology, UConn Health, 400 Farmington Avenue, Farmington, CT 06030-6406, USA.,Current address: Quantitative Biology Center, RIKEN, Osaka 565-0874, Japan
| | - Pavel Kraikivski
- Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061-0406, USA
| | - Ji Yu
- R.D.Berlin Center for Cell Analysis and Modeling, and Department of Cell Biology, UConn Health, 400 Farmington Avenue, Farmington, CT 06030-6406, USA
| | - Ann Cowan
- R.D.Berlin Center for Cell Analysis and Modeling, and Department of Cell Biology, UConn Health, 400 Farmington Avenue, Farmington, CT 06030-6406, USA
| | - Ilya Zaliapin
- Department of Mathematics and Statistics, University of Nevada-Reno, Reno, NV 89557, USA
| | - Vladimir Rodionov
- R.D.Berlin Center for Cell Analysis and Modeling, and Department of Cell Biology, UConn Health, 400 Farmington Avenue, Farmington, CT 06030-6406, USA
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6
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Mouriño-Pérez RR, Riquelme M, Callejas-Negrete OA, Galván-Mendoza JI. Microtubules and associated molecular motors in Neurospora crassa. Mycologia 2016; 108:515-27. [PMID: 26951369 DOI: 10.3852/15-323] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Accepted: 03/02/2016] [Indexed: 11/10/2022]
Abstract
The cytoskeleton provides structure, shape and movement to various cells. Microtubules (MTs) are tubular structures made of α and β-tubulin heterodimers organized in 13 protofilaments, forming a hollow cylinder. A vast group of MT-associated proteins determines the function, behavior and interaction of the MTs with other cellular components. Among these proteins, molecular motors such as the dynein-dynactin complex and kinesin superfamily play roles in MT organization and organelle transport. This article focuses on the MT cytoskeleton and associated molecular motors in the filamentous fungus Neurospora crassa In addition to reviewing current available information for this fungus and contrasting it with knowledge of other fungal species, we present new experimental results that support the role of dynein, dynactin and conventional kinesin in MT organization, dynamics and transport of subcellular structures (nuclei and secretory vesicles). In wild type hyphae of N. crassa, cytoplasmic MTs are arranged longitudinally along hyphae and display a helical curvature. They interlace with one another to form a network throughout the cytoplasm. N. crassa dynein and dynactin mutants have a scant and disorganized MT cytoskeleton, an erratic and reduced Spitzenkörper (Spk) and distorted hyphal morphology. In contrast, hyphae of mutants with defective conventional kinesin exhibit only minor disruptions in MT and Spk organization. Although nuclear positioning is affected in all mutants, the MT-associated motor proteins are not major contributors to nuclear movement during hyphal growth. Cytoplasmic bulk flow is the vehicle for nuclear displacement in growing hyphal regions of N. crassa Motors are involved in nuclei saltatory movements in both retrograde or anterograde direction. In the dynein and kinesin mutants, micro and macrovesicles can reach the Spk, although growth is slightly impaired and the Spk displays an erratic path. Hyphal growth requires MTs, and their associated motors are required for their organization and dynamics and Spk integrity.
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Affiliation(s)
- Rosa Reyna Mouriño-Pérez
- Departamento de Microbiología. Centro de Investigación Científica y de Educación Superior de Ensenada, CICESE, Ensenada B.C. 22860 Mexico
| | - Meritxell Riquelme
- Departamento de Microbiología. Centro de Investigación Científica y de Educación Superior de Ensenada, CICESE, Ensenada B.C. 22860 Mexico
| | - Olga Alicia Callejas-Negrete
- Departamento de Microbiología. Centro de Investigación Científica y de Educación Superior de Ensenada, CICESE, Ensenada B.C. 22860 Mexico
| | - José Iván Galván-Mendoza
- Unidad de Microscopia Confocal y Multifotónica, CINVESTAV-Zacatenco. San Pedro Zacatenco, 07360 Ciudad de México DF, Mexico
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7
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Alieva IB, Berezinskaya T, Borisy GG, Vorobjev IA. Centrosome nucleates numerous ephemeral microtubules and only few of them participate in the radial array. Cell Biol Int 2015; 39:1203-16. [PMID: 25998195 DOI: 10.1002/cbin.10492] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Accepted: 05/16/2015] [Indexed: 11/10/2022]
Abstract
It is generally accepted that long microtubules (MTs) grow from the centrosome with their minus ends anchored there and plus ends directed towards cell membrane. However, recent findings show this scheme to be an oversimplification. To further analyze the relationship between the centrosome and the MT array we undertook a detailed study on the MTs growing from the centrosome after microinjection of Cy3 labeled tubulin and transfection of cells with EB1-GFP. To evaluate MTs around the centrosome two approaches were used: path photobleaching across the centrosome area (Komarova et al., ) and sequential image subtraction analysis (Vorobjev et al., ). We show that about 50% of MTs had been nucleated at the centrosome are short-living: their mean length was 1.8 ± 0.8 μm and their life span - 7 ± 2 s. MTs initiated from the centrosome also rarely reach cell margin, since their elongation was limited and growth after shortening (rescue) was rare. After initial growth all MTs associated with the centrosome converted to pause or shortening. After pause MTs associated with the centrosome mainly depolymerized via the plus end shortening. Stability of the minus ends of cytoplasmic MTs was the same as for centrosomal ones. We conclude that in fibroblasts (1) the default behavior of free MTs in the cell interior is biased dynamic instability (i.e., random walk of the plus ends with significant positive drift); (2) MTs born at the centrosome show "dynamic instability" type behavior with no boundary; and (3) that the extended radial array is formed predominantly by MTs not associated with the centrosome.
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Affiliation(s)
- Irina B Alieva
- A.N. Belozersky Institute of Physico-Chemical Biology, M.V. Lomonosov Moscow State University, Moscow, Russia
| | - Tatyana Berezinskaya
- Department of Cell Biology and Histology, Faculty of Biology, M.V. Lomonosov Moscow State University, Moscow, Russia
| | - Gary G Borisy
- Department of Microbiology, The Forsyth Institute Cambridge, Massachusetts, USA
| | - Ivan A Vorobjev
- A.N. Belozersky Institute of Physico-Chemical Biology, M.V. Lomonosov Moscow State University, Moscow, Russia.,Department of Cell Biology and Histology, Faculty of Biology, M.V. Lomonosov Moscow State University, Moscow, Russia
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8
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Guan X, Buchholz G, Nick P. Tubulin marker line of grapevine suspension cells as a tool to follow early stress responses. JOURNAL OF PLANT PHYSIOLOGY 2015; 176:118-128. [PMID: 25590686 DOI: 10.1016/j.jplph.2014.10.023] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Revised: 10/29/2014] [Accepted: 10/31/2014] [Indexed: 06/04/2023]
Abstract
Plant microtubules (MTs), in addition to their role in cell division and cell expansion, respond to various stress signals. To understand the biological function of this early response requires non-destructive strategies for visualization in cellular models that are highly responsive to stress signals. We have therefore generated a transgenic tubulin marker line for a cell line from the grapevine Vitis rupestris that readily responds to stress factors of defense-related and abiotic stresses based on a fusion of the green fluorescent protein with Arabidopsis β-tubulin 6. By a combination of spinning-disk confocal microscopy with quantitative image analysis, we could detect early and specific responses of MTs to defense-related and abiotic stress factors in vivo. We observed that Harpin Z (HrpZ), a bacterial elicitor that can trigger programmed cell death, rapidly eliminated radial MTs, followed by a slower depletion of the cortical array. Jasmonic acid (JA), in contrast, induced bundling of cortical MTs. Auxin reduced the thickness of cortical MTs. This effect followed a characteristic bell-shaped dose-dependency and could revert JA-induced bundling. Impeded cell expansion as a consequence of stress treatment or superoptimal auxin was linked with the appearance of intranuclear tubulin speckles. The early and stimulus-specific responses of MTs are discussed with respect to a function in processing or decoding of stress signals.
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Affiliation(s)
- Xin Guan
- Molecular Cell Biology, Botanical Institute, Karlsruhe Institute of Technology, Kaiserstraße 2, D-76128 Karlsruhe, Germany.
| | - Günther Buchholz
- RLP AgroScience/AlPlanta - Institute for Plant Research, Breitenweg 71, D-67435 Neustadt an der Weinstraße, Germany
| | - Peter Nick
- Molecular Cell Biology, Botanical Institute, Karlsruhe Institute of Technology, Kaiserstraße 2, D-76128 Karlsruhe, Germany
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9
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Folker ES, Schulman VK, Baylies MK. Translocating myonuclei have distinct leading and lagging edges that require kinesin and dynein. Development 2013; 141:355-66. [PMID: 24335254 DOI: 10.1242/dev.095612] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Nuclei are precisely positioned within all cells, and mispositioned nuclei are a hallmark of many muscle diseases. Myonuclear positioning is dependent on Kinesin and Dynein, but interactions between these motor proteins and their mechanisms of action are unclear. We find that in developing Drosophila muscles, Dynein and Kinesin work together to move nuclei in a single direction by two separate mechanisms that are spatially segregated. First, the two motors work together in a sequential pathway that acts from the cell cortex at the muscle poles. This mechanism requires Kinesin-dependent localization of Dynein to cell cortex near the muscle pole. From this location Dynein can pull microtubule minus-ends and the attached myonuclei toward the muscle pole. Second, the motors exert forces directly on individual nuclei independently of the cortical pathway. However, the activities of the two motors on the nucleus are polarized relative to the direction of myonuclear translocation: Kinesin acts at the leading edge of the nucleus, whereas Dynein acts at the lagging edge of the nucleus. Consistent with the activities of Kinesin and Dynein being polarized on the nucleus, nuclei rarely change direction, and those that do, reorient to maintain the same leading edge. Conversely, nuclei in both Kinesin and Dynein mutant embryos change direction more often and do not maintain the same leading edge when changing directions. These data implicate Kinesin and Dynein in two distinct and independently regulated mechanisms of moving myonuclei, which together maximize the ability of myonuclei to achieve their proper localizations within the constraints imposed by embryonic development.
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Affiliation(s)
- Eric S Folker
- Program in Developmental Biology, Sloan Kettering Institute, New York, NY 10065, USA
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10
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11
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Zhu X, Kaverina I. Golgi as an MTOC: making microtubules for its own good. Histochem Cell Biol 2013; 140:361-7. [PMID: 23821162 DOI: 10.1007/s00418-013-1119-4] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/22/2013] [Indexed: 12/22/2022]
Abstract
In cells, microtubules (MTs) are nucleated at MT-organizing centers (MTOCs). The centrosome-based MTOCs organize radial MT arrays, which are often not optimal for polarized trafficking. A recently discovered subset of non-centrosomal MTs nucleated at the Golgi has proven to be indispensable for the Golgi organization, post-Golgi trafficking and cell polarity. Here, we summarize the history of this discovery, known molecular prerequisites of MT nucleation at the Golgi and unique functions of Golgi-derived MTs.
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Affiliation(s)
- Xiaodong Zhu
- Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
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12
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Buljan VA, Holsinger RMD, Brown D, Bohorquez-Florez JJ, Hambly BD, Delikatny EJ, Ivanova EP, Banati RB. Spinodal decomposition and the emergence of dissipative transient periodic spatio-temporal patterns in acentrosomal microtubule multitudes of different morphology. CHAOS (WOODBURY, N.Y.) 2013; 23:023120. [PMID: 23822485 DOI: 10.1063/1.4807909] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We have studied a spontaneous self-organization dynamics in a closed, dissipative (in terms of guansine 5'-triphosphate energy dissipation), reaction-diffusion system of acentrosomal microtubules (those nucleated and organized in the absence of a microtubule-organizing centre) multitude constituted of straight and curved acentrosomal microtubules, in highly crowded conditions, in vitro. Our data give experimental evidence that cross-diffusion in conjunction with excluded volume is the underlying mechanism on basis of which acentrosomal microtubule multitudes of different morphologies (straight and curved) undergo a spatial-temporal demix. Demix is constituted of a bifurcation process, manifested as a slow isothermal spinodal decomposition, and a dissipative process of transient periodic spatio-temporal pattern formation. While spinodal decomposition is an energy independent process, transient periodic spatio-temporal pattern formation is accompanied by energy dissipative process. Accordingly, we have determined that the critical threshold for slow, isothermal spinodal decomposition is 1.0 ± 0.05 mg/ml of microtubule protein concentration. We also found that periodic spacing of transient periodic spatio-temporal patterns was, in the overall, increasing versus time. For illustration, we found that a periodic spacing of the same pattern was 0.375 ± 0.036 mm, at 36 °C, at 155th min, while it was 0.540 ± 0.041 mm at 31 °C, and at 275th min after microtubule assembly started. The lifetime of transient periodic spatio-temporal patterns spans from half an hour to two hours approximately. The emergence of conditions of macroscopic symmetry breaking (that occur due to cross-diffusion in conjunction with excluded volume) may have more general but critical importance in morphological pattern development in complex, dissipative, but open cellular systems.
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Affiliation(s)
- Vlado A Buljan
- Brain and Mind Research Institute, Sydney Medical School, The University of Sydney, Sydney NSW 2050, Australia.
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13
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Neuronal polarity: demarcation, growth and commitment. Curr Opin Cell Biol 2012; 24:547-53. [PMID: 22726583 DOI: 10.1016/j.ceb.2012.05.011] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Accepted: 05/23/2012] [Indexed: 02/03/2023]
Abstract
In a biological sense, polarity refers to the extremity of the main axis of an organelle, cell, or organism. In neurons, morphological polarity begins with the appearance of the first neurite from the cell body. In multipolar neurons, a second phase of polarization occurs when a single neurite initiates a phase of rapid growth to become the neuron's axon, while the others later differentiate as dendrites. Finally, during a third phase, axons and dendrites develop an elaborate architecture, acquiring special morphological and molecular features that commit them to their final identities. Mechanistically, each phase must be preceded by spatial restriction of growth activity. We will review recent work on the mechanisms underlying the polarized growth of neurons.
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14
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Ogden A, Rida PCG, Aneja R. Let's huddle to prevent a muddle: centrosome declustering as an attractive anticancer strategy. Cell Death Differ 2012; 19:1255-67. [PMID: 22653338 DOI: 10.1038/cdd.2012.61] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Nearly a century ago, cell biologists postulated that the chromosomal aberrations blighting cancer cells might be caused by a mysterious organelle-the centrosome-that had only just been discovered. For years, however, this enigmatic structure was neglected in oncologic investigations and has only recently reemerged as a key suspect in tumorigenesis. A majority of cancer cells, unlike healthy cells, possess an amplified centrosome complement, which they manage to coalesce neatly at two spindle poles during mitosis. This clustering mechanism permits the cell to form a pseudo-bipolar mitotic spindle for segregation of sister chromatids. On rare occasions this mechanism fails, resulting in declustered centrosomes and the assembly of a multipolar spindle. Spindle multipolarity consigns the cell to an almost certain fate of mitotic arrest or death. The catastrophic nature of multipolarity has attracted efforts to develop drugs that can induce declustering in cancer cells. Such chemotherapeutics would theoretically spare healthy cells, whose normal centrosome complement should preclude multipolar spindle formation. In search of the 'Holy Grail' of nontoxic, cancer cell-selective, and superiorly efficacious chemotherapy, research is underway to elucidate the underpinnings of centrosome clustering mechanisms. Here, we detail the progress made towards that end, highlighting seminal work and suggesting directions for future research, aimed at demystifying this riddling cellular tactic and exploiting it for chemotherapeutic purposes. We also propose a model to highlight the integral role of microtubule dynamicity and the delicate balance of forces on which cancer cells rely for effective centrosome clustering. Finally, we provide insights regarding how perturbation of this balance may pave an inroad for inducing lethal centrosome dispersal and death selectively in cancer cells.
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Affiliation(s)
- A Ogden
- Department of Biology, Georgia State University, Atlanta, 30303, USA
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15
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Centrosomes, microtubules and neuronal development. Mol Cell Neurosci 2011; 48:349-58. [DOI: 10.1016/j.mcn.2011.05.004] [Citation(s) in RCA: 117] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Revised: 05/12/2011] [Accepted: 05/15/2011] [Indexed: 11/24/2022] Open
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16
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Swanson D, Wingreen NS. Active biopolymers confer fast reorganization kinetics. PHYSICAL REVIEW LETTERS 2011; 107:218103. [PMID: 22181930 DOI: 10.1103/physrevlett.107.218103] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2010] [Indexed: 05/31/2023]
Abstract
Many cytoskeletal biopolymers are "active," consuming energy in large quantities. In this Letter, we identify a fundamental difference between active polymers and passive, equilibrium polymers: for equal mean lengths, active polymers can reorganize faster than equilibrium polymers. We show that equilibrium polymers are intrinsically limited to linear scaling between mean lifetime (or mean first-passage time, or MFPT) and mean length, MFPT∼<L>, by analogy to 1D Potts models. By contrast, we present a simple active-polymer model that improves upon this scaling, such that MFPT∼<L>(1/2). Since, to be biologically useful, structural biopolymers must typically be many monomers long yet respond dynamically to the needs of the cell, the difference in reorganization kinetics may help to justify the active polymers' greater energy cost.
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Affiliation(s)
- Douglas Swanson
- Department of Physics, Princeton University, New Jersey 08544, USA.
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17
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Bennett M. Schizophrenia: susceptibility genes, dendritic-spine pathology and gray matter loss. Prog Neurobiol 2011; 95:275-300. [DOI: 10.1016/j.pneurobio.2011.08.003] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2011] [Revised: 08/12/2011] [Accepted: 08/15/2011] [Indexed: 02/01/2023]
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18
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Chen G, Rogers AK, League GP, Nam SC. Genetic interaction of centrosomin and bazooka in apical domain regulation in Drosophila photoreceptor. PLoS One 2011; 6:e16127. [PMID: 21253601 PMCID: PMC3017087 DOI: 10.1371/journal.pone.0016127] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2010] [Accepted: 12/10/2010] [Indexed: 12/26/2022] Open
Abstract
Background Cell polarity genes including Crumbs (Crb) and Par complexes are essential for controlling photoreceptor morphogenesis. Among the Crb and Par complexes, Bazooka (Baz, Par-3 homolog) acts as a nodal component for other cell polarity proteins. Therefore, finding other genes interacting with Baz will help us to understand the cell polarity genes' role in photoreceptor morphogenesis. Methodology/Principal Findings Here, we have found a genetic interaction between baz and centrosomin (cnn). Cnn is a core protein for centrosome which is a major microtubule-organizing center. We analyzed the effect of the cnn mutation on developing eyes to determine its role in photoreceptor morphogenesis. We found that Cnn is dispensable for retinal differentiation in eye imaginal discs during the larval stage. However, photoreceptors deficient in Cnn display dramatic morphogenesis defects including the mislocalization of Crumbs (Crb) and Bazooka (Baz) during mid-stage pupal eye development, suggesting that Cnn is specifically required for photoreceptor morphogenesis during pupal eye development. This role of Cnn in apical domain modulation was further supported by Cnn's gain-of-function phenotype. Cnn overexpression in photoreceptors caused the expansion of the apical Crb membrane domain, Baz and adherens junctions (AJs). Conclusions/Significance These results strongly suggest that the interaction of Baz and Cnn is essential for apical domain and AJ modulation during photoreceptor morphogenesis, but not for the initial photoreceptor differentiation in the Drosophila photoreceptor.
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Affiliation(s)
- Geng Chen
- Department of Biology, Baylor University, Waco, Texas, United States of America
| | - Alicia K. Rogers
- Department of Biology, Baylor University, Waco, Texas, United States of America
| | - Garrett P. League
- Department of Biology, Baylor University, Waco, Texas, United States of America
| | - Sang-Chul Nam
- Department of Biology, Baylor University, Waco, Texas, United States of America
- * E-mail:
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19
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Zhu X, Kaverina I. Quantification of asymmetric microtubule nucleation at subcellular structures. Methods Mol Biol 2011; 777:235-44. [PMID: 21773933 DOI: 10.1007/978-1-61779-252-6_17] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Cell polarization is important for multiple physiological processes. In polarized cells, microtubules (MTs) are organized into a spatially polarized array. Generally, in nondifferentiated cells, it is assumed that MTs are symmetrically nucleated exclusively from centrosome [microtubule organizing center (MTOC)] and then reorganized into the asymmetric array. We have recently identified the Golgi complex as an additional MTOC that asymmetrically nucleates MTs toward one side of the cell. Methods used for alternative MTOC identification include microtubule regrowth after complete drug-induced depolymerization and tracking of growing microtubules using fluorescently labeled MT +TIP binding proteins in living cells. These approaches can be used for quantification of MT nucleation sites at diverse subcellular structures.
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Affiliation(s)
- Xiaodong Zhu
- Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN, USA.
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20
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Doubrovinski K, Kruse K. Self-organization in systems of treadmilling filaments. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2010; 31:95-104. [PMID: 20087625 DOI: 10.1140/epje/i2010-10548-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2008] [Revised: 10/22/2009] [Accepted: 11/26/2009] [Indexed: 05/28/2023]
Abstract
The cytoskeleton is an important substructure of living cells, playing essential roles in cell division, cell locomotion, and the internal organization of subcellular components. Physically, the cytoskeleton is an active polar gel, that is, a system of polar filamentous polymers, which is intrinsically out of thermodynamic equilibrium. Active processes are notably involved in filament growth and can lead to net filament assembly at one end and disassembly at the other, a phenomenon called treadmilling. Here, we develop a framework for describing collective effects in systems of treadmilling filaments in the presence of agents regulating filament assembly. We find that such systems can self-organize into asters and moving filament blobs. We discuss possible implications of our findings for subcellular processes.
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21
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Ding C, Liang X, Ma L, Yuan X, Zhu X. Opposing effects of Ndel1 and alpha1 or alpha2 on cytoplasmic dynein through competitive binding to Lis1. J Cell Sci 2009; 122:2820-7. [PMID: 19622634 DOI: 10.1242/jcs.048777] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Lis1 is an essential protein whose insufficiency causes aberrant neuronal positioning during neocortical development. It is believed to regulate both cytoplasmic dynein, a microtubule minus-end-directed motor, through direct interaction, and platelet-activating factor acetylhydrolase (PAF-AH) Ib by complexing with the catalytic subunits alpha1 and alpha2. Although alpha1 and alpha2 are highly expressed in brain, their deficiencies fail to cause brain abnormality. Here, we show that overexpression of alpha2 or alpha1 results in inactivation of dynein characterized by Golgi and endosome dispersion and mitotic delay. Further overexpression of Lis1 or Ndel1, a Lis1- and dynein-binding protein that is also crucial for dynein function, restored Golgi and endosome distribution. Biochemical assays showed that alpha1 and especially alpha2, were able to compete against Ndel1 and dynein for Lis1 binding in a dose-dependent manner. Overexpression of alpha2 in developing rat brain repressed the radial migration of neurons and mitotic progression of neuroprogenitors. By contrast, a Lis1-binding-defective point mutant, alpha2(E39D), was ineffective in the above assays. These results indicate an antagonistic effect of alpha1, alpha2 and Ndel1 for Lis1 binding, probably to modulate dynein functions in vivo. They also help to explain why brain development is particularly sensitive to a decrease in Lis1 levels.
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Affiliation(s)
- Chong Ding
- Laboratory of Molecular Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
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22
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Vinogradova T, Miller PM, Kaverina I. Microtubule network asymmetry in motile cells: role of Golgi-derived array. Cell Cycle 2009; 8:2168-74. [PMID: 19556895 PMCID: PMC3163838 DOI: 10.4161/cc.8.14.9074] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Cell migration requires polarization of the cell into the leading edge and the trailing edge. Microtubules (MTs) are indispensable for polarized cell migration in the majority of cell types. To support cell polarity, MT network has to be functionally and structurally asymmetric. How is this asymmetry achieved? In interphase cells, MTs form a dynamic system radiating from a centrosome-based MT-organizing center (MTOC) to the cell edges. Symmetry of this radial array can be broken according to four general principles. Asymmetry occurs due to differential modulation of MT dynamics, relocation of existing MTs within a cell, adding an asymmetric nucleation site, and/or repositioning of a symmetric nucleation site to one side of a cell. Combinations of these asymmetry regulation principles result in a variety of asymmetric MT networks typical for diverse motile cell types. Importantly, an asymmetric MT array is formed at a non-conventional MT nucleation site, the Golgi. Here, we emphasize the contribution of this array to the asymmetry of MT network.
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Affiliation(s)
- Tatiana Vinogradova
- Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN, USA
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23
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Palmer KJ, Hughes H, Stephens DJ. Specificity of cytoplasmic dynein subunits in discrete membrane-trafficking steps. Mol Biol Cell 2009; 20:2885-99. [PMID: 19386764 PMCID: PMC2695796 DOI: 10.1091/mbc.e08-12-1160] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2008] [Revised: 03/18/2009] [Accepted: 04/15/2009] [Indexed: 12/29/2022] Open
Abstract
The cytoplasmic dynein motor complex is known to exist in multiple forms, but few specific functions have been assigned to individual subunits. A key limitation in the analysis of dynein in intact mammalian cells has been the reliance on gross perturbation of dynein function, e.g., inhibitory antibodies, depolymerization of the entire microtubule network, or the use of expression of dominant negative proteins that inhibit dynein indirectly. Here, we have used RNAi and automated image analysis to define roles for dynein subunits in distinct membrane-trafficking processes. Depletion of a specific subset of dynein subunits, notably LIC1 (DYNC1LI1) but not LIC2 (DYNC1LI2), recapitulates a direct block of ER export, revealing that dynein is required to maintain the steady-state composition of the Golgi, through ongoing ER-to-Golgi transport. Suppression of LIC2 but not of LIC1 results in a defect in recycling endosome distribution and cytokinesis. Biochemical analyses also define the role of each subunit in stabilization of the dynein complex; notably, suppression of DHC1 or IC2 results in concomitant loss of Tctex1. Our data demonstrate that LIC1 and LIC2 define distinct dynein complexes that function at the Golgi versus recycling endosomes, respectively, suggesting that functional populations of dynein mediate discrete intracellular trafficking pathways.
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Affiliation(s)
- Krysten J. Palmer
- Cell Biology Laboratories, Department of Biochemistry, School of Medical Sciences, University of Bristol, Bristol, BS8 1TD, United Kingdom
| | - Helen Hughes
- Cell Biology Laboratories, Department of Biochemistry, School of Medical Sciences, University of Bristol, Bristol, BS8 1TD, United Kingdom
| | - David J. Stephens
- Cell Biology Laboratories, Department of Biochemistry, School of Medical Sciences, University of Bristol, Bristol, BS8 1TD, United Kingdom
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24
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Bicek AD, Tüzel E, Demtchouk A, Uppalapati M, Hancock WO, Kroll DM, Odde DJ. Anterograde microtubule transport drives microtubule bending in LLC-PK1 epithelial cells. Mol Biol Cell 2009; 20:2943-53. [PMID: 19403700 PMCID: PMC2695801 DOI: 10.1091/mbc.e08-09-0909] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2008] [Revised: 02/23/2009] [Accepted: 04/16/2009] [Indexed: 01/01/2023] Open
Abstract
Microtubules (MTs) have been proposed to act mechanically as compressive struts that resist both actomyosin contractile forces and their own polymerization forces to mechanically stabilize cell shape. To identify the origin of MT bending, we directly observed MT bending and F-actin transport dynamics in the periphery of LLC-PK1 epithelial cells. We found that F-actin is nearly stationary in these cells even as MTs are deformed, demonstrating that MT bending is not driven by actomyosin contractility. Furthermore, the inhibition of myosin II activity through the use of blebbistatin results in microtubules that are still dynamically bending. In addition, as determined by fluorescent speckle microscopy, MT polymerization rarely results, if ever, in bending. We suppressed dynamic instability using nocodazole, and we observed no qualitative change in the MT bending dynamics. Bending most often results from anterograde transport of proximal portions of the MT toward a nearly stationary distal tip. Interestingly, we found that in an in vitro kinesin-MT gliding assay, MTs buckle in a similar manner. To make quantitative comparisons, we measured curvature distributions of observed MTs and found that the in vivo and in vitro curvature distributions agree quantitatively. In addition, the measured MT curvature distribution is not Gaussian, as expected for a thermally driven semiflexible polymer, indicating that thermal forces play a minor role in MT bending. We conclude that many of the known mechanisms of MT deformation, such as polymerization and acto-myosin contractility, play an inconsequential role in mediating MT bending in LLC-PK1 cells and that MT-based molecular motors likely generate most of the strain energy stored in the MT lattice. The results argue against models in which MTs play a major mechanical role in LLC-PK1 cells and instead favor a model in which mechanical forces control the spatial distribution of the MT array.
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Affiliation(s)
| | - Erkan Tüzel
- Institute for Mathematics and Its Applications, University of Minnesota, Minneapolis, MN 55455
| | | | - Maruti Uppalapati
- Department of Bioengineering, The Pennsylvania State University, University Park, PA 16802; and
| | - William O. Hancock
- Department of Bioengineering, The Pennsylvania State University, University Park, PA 16802; and
| | - Daniel M. Kroll
- Department of Physics, North Dakota State University, Fargo, ND 58105
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25
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Abstract
Tight regulation of centrosome duplication is critical to ensure that centrosome number doubles once and only once per cell cycle. Superimposed onto this centrosome duplication cycle is a functional centrosome cycle in which they alternate between phases of quiescence and robust microtubule (MT) nucleation and MT-anchoring activities. In vertebrate cycling cells, interphase centrioles accumulate less pericentriolar material (PCM), reducing their MT nucleation capacity. In mitosis, centrosomes mature, accumulating more PCM to increase their nucleation and anchoring capacities to form robust MT asters. Interestingly, functional cycles of centrosomes can be altered to suit the cell's needs. Some interphase centrosomes function as a microtubule-organizing center by increasing their ability to anchor MTs to form centrosomal radial arrays. Other interphase centrosomes maintain their MT nucleation capacity but reduce/eliminate their MT-anchoring capacity. Recent work demonstrates that Drosophila cells take this to the extreme, whereby centrioles lose all detectable PCM during interphase, offering an explanation as to how centrosome-deficient flies develop to adulthood. Drosophila stem cells further modify the functional cycle by differentially regulating their two centrioles - a situation that seems important for stem cell asymmetric divisions, as misregulation of centrosome duplication in stem/progenitor cells can promote tumor formation. Here, we review recent findings that describe variations in the functional cycle of centrosomes.
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Affiliation(s)
- Nasser M Rusan
- Department of Biology, University of North Carolina at Chapel Hill, CB#3280, Coker Hall, Chapel Hill, NC 27599, USA.
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26
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Bennett A O MR. Dual constraints on synapse formation and regression in schizophrenia: neuregulin, neuroligin, dysbindin, DISC1, MuSK and agrin. Aust N Z J Psychiatry 2008; 42:662-77. [PMID: 18622774 DOI: 10.1080/00048670802203467] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
During adolescence there is a loss of approximately 30% of the synapses formed in the cortex during childhood. Comprehensive studies of the visual cortex show that this loss of synapses does not occur as a consequence of less appropriate projections being eliminated in favour of more appropriate ones. Rather it seems that synapses with low efficacy for transmission are eliminated in favour of those with higher efficacy. The loss of low-efficacy synapses is known, on theoretical grounds, to enhance the function of neural networks, but large synapse losses lead to failure of network function. In the dorsolateral prefrontal cortex (DLPC) of those suffering from schizophrenia the number of synapses is relatively very low, approximately 60% lower than that observed in normal childhood. It is not known if this is due to an additional loss over that during normal adolescence or whether it results from a failure to form a normal complement of synapses during childhood. The first study of synapse loss in the mammalian nervous system was made on the neuromuscular junction at Sydney University in 1974. Since then this junction has provided principal insights into the molecular basis of synapse formation and regression, so providing a paradigm for investigations of these phenomena in the DLPC. For example the molecules muscle-specific receptor tyrosine kinase (MuSK), agrin and neuregulin have been identified and their critical roles in the formation and maintenance of synapses elucidated. Loss of function of MuSK or agrin leads to failure of neuromuscular synapse formation as well as a loss of approximately 30% of excitatory synapses in the cortex. Similar synapse loss occurs on failure of neuregulin in vitro and of neuroligin in vivo. It is suggested that three important questions need to be answered: first, over what development period are the synapse numbers in DLPC of subjects with schizophrenia lower than normal; second, what are the relative importance of MuSK/agrin, neuregulin/ErB and neurexin/neuroligin in synapse formation and regression in the DLPC; and third, to what extent have these molecules gone awry in schizophrenia.
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Affiliation(s)
- Maxwell R Bennett A O
- Brain and Mind Research Institute, University of Sydney, 100 Mallett Street, Camperdown, NSW 2006, Australia.
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27
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Rogers GC, Rusan NM, Peifer M, Rogers SL. A multicomponent assembly pathway contributes to the formation of acentrosomal microtubule arrays in interphase Drosophila cells. Mol Biol Cell 2008; 19:3163-78. [PMID: 18463166 DOI: 10.1091/mbc.e07-10-1069] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
In animal cells, centrosomes nucleate microtubules that form polarized arrays to organize the cytoplasm. Drosophila presents an interesting paradox however, as centrosome-deficient mutant animals develop into viable adults. To understand this discrepancy, we analyzed behaviors of centrosomes and microtubules in Drosophila cells, in culture and in vivo, using a combination of live-cell imaging, electron microscopy, and RNAi. The canonical model of the cycle of centrosome function in animal cells states that centrosomes act as microtubule-organizing centers throughout the cell cycle. Unexpectedly, we found that many Drosophila cell-types display an altered cycle, in which functional centrosomes are only present during cell division. On mitotic exit, centrosomes disassemble producing interphase cells containing centrioles that lack microtubule-nucleating activity. Furthermore, steady-state interphase microtubule levels are not changed by codepleting both gamma-tubulins. However, gamma-tubulin RNAi delays microtubule regrowth after depolymerization, suggesting that it may function partially redundantly with another pathway. Therefore, we examined additional microtubule nucleating factors and found that Mini-spindles, CLIP-190, EB1, or dynein RNAi also delayed microtubule regrowth; surprisingly, this was not further prolonged when we codepleted gamma-tubulins. Taken together, these results modify our view of the cycle of centrosome function and reveal a multi-component acentrosomal microtubule assembly pathway to establish interphase microtubule arrays in Drosophila.
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Affiliation(s)
- Gregory C Rogers
- Department of Biology, Lineberger Comprehensive Cancer Center, and Carolina Center for Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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28
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Burakov AV, Zhapparova ON, Kovalenko OV, Zinovkina LA, Potekhina ES, Shanina NA, Weiss DG, Kuznetsov SA, Nadezhdina ES. Ste20-related protein kinase LOSK (SLK) controls microtubule radial array in interphase. Mol Biol Cell 2008; 19:1952-61. [PMID: 18287541 DOI: 10.1091/mbc.e06-12-1156] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Interphase microtubules are organized into a radial array with centrosome in the center. This organization is a subject of cellular regulation that can be driven by protein phosphorylation. Only few protein kinases that regulate microtubule array in interphase cells have been described. Ste20-like protein kinase LOSK (SLK) was identified as a microtubule and centrosome-associated protein. In this study we have shown that the inhibition of LOSK activity by dominant-negative mutant K63R-DeltaT or by LOSK depletion with RNAi leads to unfocused microtubule arrangement. Microtubule disorganization is prominent in Vero, CV-1, and CHO-K1 cells but less distinct in HeLa cells. The effect is a result neither of microtubule stabilization nor of centrosome disruption. In cells with suppressed LOSK activity centrosomes are unable to anchor or to cap microtubules, though they keep nucleating microtubules. These centrosomes are depleted of dynactin. Vero cells overexpressing K63R-DeltaT have normal dynactin "comets" at microtubule ends and unaltered morphology of Golgi complex but are unable to polarize it at the wound edge. We conclude that protein kinase LOSK is required for radial microtubule organization and for the proper localization of Golgi complex in various cell types.
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Affiliation(s)
- Anton V Burakov
- Institute of Protein Research, Russian Academy of Science, 142290 Pushchino, Moscow Region, Russian Federation
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29
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Burakov A, Kovalenko O, Semenova I, Zhapparova O, Nadezhdina E, Rodionov V. Cytoplasmic dynein is involved in the retention of microtubules at the centrosome in interphase cells. Traffic 2007; 9:472-80. [PMID: 18182007 DOI: 10.1111/j.1600-0854.2007.00698.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cytoplasmic dynein is known to be involved in the establishment of radial microtubule (MT) arrays. During mitosis, dynein activity is required for tethering of the MTs at the spindle poles. In interphase cells, dynein inhibitors induce loss of radial MT organization; however, the exact role of dynein in the maintenance of MT arrays is unclear. Here, we examined the effect of dynein inhibitors on MT distribution and the centrosome protein composition in cultured fibroblasts. We found that while these inhibitors induced rapid (t(1/2) approximately 20 min) loss of radial MT organization, the levels of key centrosomal proteins or the rates of MT nucleation did not change significantly in dynein-inhibited cells, suggesting that the loss of dynein activity does not affect the structural integrity of the centrosome or its capacity to nucleate MTs. Live observations of the centrosomal activity showed that dynein inhibition enhanced the detachment of MTs from the centrosome. We conclude that the primary role of dynein in the maintenance of a radial MT array in interphase cells consists of retention of MTs at the centrosome and hypothesize that dynein has a role in the MT retention, separate from the delivery to the centrosome of MT-anchoring proteins.
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Affiliation(s)
- Anton Burakov
- Department of Cell Biology and Center for Cell Analysis and Modeling, University of Connecticut Health Center, 263 Farmington Avenue-MC1507, Farmington, CT 06032-1507, USA
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30
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Zhapparova ON, Burakov AV, Nadezhdina ES. The centrosome keeps nucleating microtubules but looses the ability to anchor them after the inhibition of dynein-dynactin complex. BIOCHEMISTRY (MOSCOW) 2007; 72:1233-40. [DOI: 10.1134/s0006297907110090] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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31
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Delanoue R, Herpers B, Soetaert J, Davis I, Rabouille C. Drosophila Squid/hnRNP helps Dynein switch from a gurken mRNA transport motor to an ultrastructural static anchor in sponge bodies. Dev Cell 2007; 13:523-38. [PMID: 17925228 DOI: 10.1016/j.devcel.2007.08.022] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2006] [Revised: 01/27/2007] [Accepted: 08/29/2007] [Indexed: 11/23/2022]
Abstract
In Drosophila oocytes, dorso-anterior transport of gurken mRNA requires both the Dynein motor and the heterogeneous nuclear ribonucleoprotein (hnRNP) Squid. We show that gurken transcripts are transported directly on microtubules by Dynein in nonmembranous electron-dense transport particles that also contain Squid and the transport cofactors Egalitarian and Bicaudal-D. At its destination, gurken mRNA is statically anchored by Dynein within large electron-dense cytoplasmic structures known as sponge bodies. Egalitarian and Bicaudal-D contribute only to active transport, whereas Dynein and Squid are also required for gurken mRNA anchoring and the integrity of sponge bodies. Disrupting Dynein function disperses gurken mRNA homogeneously throughout the cytoplasm, whereas the loss of Squid function converts the sponge bodies into active transport particles. We propose that Dynein acts as a static structural component for the assembly of gurken mRNA transport and anchoring complexes, and that Squid is required for the dynamic conversion of transport particles to sponge bodies.
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Affiliation(s)
- Renald Delanoue
- Wellcome Trust Centre for Cell Biology, Michael Swann Building, University of Edinburgh, Mayfield Road, Edinburgh EH9 3JR, United Kingdom
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32
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Efimov A, Kharitonov A, Efimova N, Loncarek J, Miller PM, Andreyeva N, Gleeson P, Galjart N, Maia ARR, McLeod IX, Yates JR, Maiato H, Khodjakov A, Akhmanova A, Kaverina I. Asymmetric CLASP-dependent nucleation of noncentrosomal microtubules at the trans-Golgi network. Dev Cell 2007; 12:917-30. [PMID: 17543864 PMCID: PMC2705290 DOI: 10.1016/j.devcel.2007.04.002] [Citation(s) in RCA: 397] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2006] [Revised: 03/05/2007] [Accepted: 04/05/2007] [Indexed: 10/23/2022]
Abstract
Proper organization of microtubule arrays is essential for intracellular trafficking and cell motility. It is generally assumed that most if not all microtubules in vertebrate somatic cells are formed by the centrosome. Here we demonstrate that a large number of microtubules in untreated human cells originate from the Golgi apparatus in a centrosome-independent manner. Both centrosomal and Golgi-emanating microtubules need gamma-tubulin for nucleation. Additionally, formation of microtubules at the Golgi requires CLASPs, microtubule-binding proteins that selectively coat noncentrosomal microtubule seeds. We show that CLASPs are recruited to the trans-Golgi network (TGN) at the Golgi periphery by the TGN protein GCC185. In sharp contrast to radial centrosomal arrays, microtubules nucleated at the peripheral Golgi compartment are preferentially oriented toward the leading edge in motile cells. We propose that Golgi-emanating microtubules contribute to the asymmetric microtubule networks in polarized cells and support diverse processes including post-Golgi transport to the cell front.
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Affiliation(s)
- Andrey Efimov
- Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN 37232-8240, USA
| | | | - Nadia Efimova
- Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN 37232-8240, USA
| | - Jadranka Loncarek
- Wadsworth Center, New York State Department of Health, Albany, NY 12201-0509, USA
| | - Paul M. Miller
- Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN 37232-8240, USA
| | | | - Paul Gleeson
- Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Vic 3010, Australia
| | - Niels Galjart
- Department of Cell Biology and Genetics, Erasmus MC, 3000 DR Rotterdam, The Netherlands
| | - Ana R. R. Maia
- Institute for Molecular Cell Biology & Laboratory of Molecular and Cell Biology, Faculdade de Medicine, University Porto, 4050-345 Porto, Portugal
| | - Ian X. McLeod
- Department of Cell Biology, Scripps Research Institute, La Jolla, CA 93037, USA
| | - John R. Yates
- Department of Cell Biology, Scripps Research Institute, La Jolla, CA 93037, USA
| | - Helder Maiato
- Institute for Molecular Cell Biology & Laboratory of Molecular and Cell Biology, Faculdade de Medicine, University Porto, 4050-345 Porto, Portugal
| | - Alexey Khodjakov
- Wadsworth Center, New York State Department of Health, Albany, NY 12201-0509, USA
| | - Anna Akhmanova
- Department of Cell Biology and Genetics, Erasmus MC, 3000 DR Rotterdam, The Netherlands
| | - Irina Kaverina
- Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN 37232-8240, USA
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33
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Burakov AV, Nadezhdina ES. Dynein and dynactin as organizers of the system of cell microtubules. Russ J Dev Biol 2006. [DOI: 10.1134/s1062360406050018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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34
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Adhiambo C, Forney JD, Asai DJ, LeBowitz JH. The two cytoplasmic dynein-2 isoforms in Leishmania mexicana perform separate functions. Mol Biochem Parasitol 2006; 143:216-25. [PMID: 16054709 DOI: 10.1016/j.molbiopara.2005.04.017] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2004] [Revised: 04/07/2005] [Accepted: 04/20/2005] [Indexed: 11/23/2022]
Abstract
Eukaryotic organisms with cilia or flagella typically express two non-axonemal or "cytoplasmic" dyneins, dynein-1 and dynein-2. Interestingly, we find that Leishmania mexicana is unusual and contains two distinct cytoplasmic dynein-2 heavy chain genes (designated LmxDHC2.1 and LmxDHC2.2) along with a single dynein-1 heavy chain (LmxDHC1). Disruption of LmxDHC2.2 resulted in immotile parasites that had a rounded cell body. Although they assume amastigote morphology, immunoblot analysis of these cells demonstrates protein expression consistent with the promastigote stage. Ultrastructural analysis revealed non-emergent flagella that lacked the paraflagellar rod and an axoneme with deficiencies in several components. We confirmed the absence of paraflagellar rod proteins PFR1 and PFR2. These results show that LmxDHC2.2 is required for flagellar assembly and also participates in the maintenance of promastigote cell shape. In contrast to the results with LmxDHC2.2, we were unable to generate homologous disruptions of LmxDHC2.1. This result suggests that, unlike LmxDHC2.2, LmxDHC2.1 is an essential gene in Leishmania. Together, these findings demonstrate that the two dynein-2 heavy chain isoforms in Leishmania perform distinct functions. The observation that the genomes of Leishmania major, Leishmania infantum and Trypanosoma brucei also contain two dynein-2 isoforms suggests that this unusual aspect of cytoplasmic dynein is a conserved feature of the kinetoplastids.
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Affiliation(s)
- Christine Adhiambo
- Purdue University, Department of Biochemistry, 175 S. University Street, West Lafayette, IN 47907-2063, USA
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35
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Reilein A, Yamada S, Nelson WJ. Self-organization of an acentrosomal microtubule network at the basal cortex of polarized epithelial cells. ACTA ACUST UNITED AC 2005; 171:845-55. [PMID: 16314429 PMCID: PMC2171299 DOI: 10.1083/jcb.200505071] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Mechanisms underlying the organization of centrosome-derived microtubule arrays are well understood, but less is known about how acentrosomal microtubule networks are formed. The basal cortex of polarized epithelial cells contains a microtubule network of mixed polarity. We examined how this network is organized by imaging microtubule dynamics in acentrosomal basal cytoplasts derived from these cells. We show that the steady-state microtubule network appears to form by a combination of microtubule-microtubule and microtubule-cortex interactions, both of which increase microtubule stability. We used computational modeling to determine whether these microtubule parameters are sufficient to generate a steady-state acentrosomal microtubule network. Microtubules undergoing dynamic instability without any stabilization points continuously remodel their organization without reaching a steady-state network. However, the addition of increased microtubule stabilization at microtubule-microtubule and microtubule-cortex interactions results in the rapid assembly of a steady-state microtubule network in silico that is remarkably similar to networks formed in situ. These results define minimal parameters for the self-organization of an acentrosomal microtubule network.
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Affiliation(s)
- Amy Reilein
- Department of Biological Sciences, Beckman Center for Molecular and Genetic Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
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36
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Guo J, Yang Z, Song W, Chen Q, Wang F, Zhang Q, Zhu X. Nudel contributes to microtubule anchoring at the mother centriole and is involved in both dynein-dependent and -independent centrosomal protein assembly. Mol Biol Cell 2005; 17:680-9. [PMID: 16291865 PMCID: PMC1356579 DOI: 10.1091/mbc.e05-04-0360] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The centrosome is the major microtubule-organizing center in animal cells. Although the cytoplasmic dynein regulator Nudel interacts with centrosomes, its role herein remains unclear. Here, we show that in Cos7 cells Nudel is a mother centriole protein with rapid turnover independent of dynein activity. During centriole duplication, Nudel targets to the new mother centriole later than ninein but earlier than dynactin. Its centrosome localization requires a C-terminal region that is essential for associations with dynein, dynactin, pericentriolar material (PCM)-1, pericentrin, and gamma-tubulin. Overexpression of a mutant Nudel lacking this region, a treatment previously shown to inactivate dynein, dislocates centrosomal Lis1, dynactin, and PCM-1, with little influence on pericentrin and gamma-tubulin in Cos7 and HeLa cells. Silencing Nudel in HeLa cells markedly decreases centrosomal targeting of all the aforementioned proteins. Silencing Nudel also represses centrosomal MT nucleation and anchoring. Furthermore, Nudel can interact with pericentrin independently of dynein. Our current results suggest that Nudel plays a role in both dynein-mediated centripetal transport of dynactin, Lis1, and PCM-1 as well as in dynein-independent centrosomal targeting of pericentrin and gamma-tubulin. Moreover, Nudel seems to tether dynactin and dynein to the mother centriole for MT anchoring.
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Affiliation(s)
- Jing Guo
- Laboratory of Molecular Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, and Graduate School, Chinese Academy of Sciences, Shanghai 200031, China
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37
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Malikov V, Cytrynbaum EN, Kashina A, Mogilner A, Rodionov V. Centering of a radial microtubule array by translocation along microtubules spontaneously nucleated in the cytoplasm. Nat Cell Biol 2005; 7:1213-8. [PMID: 16273095 DOI: 10.1038/ncb1332] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2005] [Accepted: 10/18/2005] [Indexed: 11/08/2022]
Abstract
Positioning of a radial array of microtubules (MTs) in the cell centre is crucial for cytoplasmic organization, but the mechanisms of such centering are difficult to study in intact cells that have pre-formed radial arrays. Here, we use cytoplasmic fragments of melanophores, and cytoplasts of BS-C-1 cells to study MT centering mechanisms. Using live imaging and computer modelling, we show that the MT aster finds a central location in the cytoplasm by moving along spontaneously nucleated non-astral MTs towards a point at which MT nucleation events occur equally on all sides. We hypothesize that similar mechanisms, in the presence of the centrosome, contribute to this centering mechanism and ensure the robustness of cytoplasmic organization.
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Affiliation(s)
- Viacheslav Malikov
- Department of Cell Biology and Center for Cell Analysis and Modeling, University of Connecticut Health Center, Farmington, CT 06032-1507, USA
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38
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Delgehyr N, Sillibourne J, Bornens M. Microtubule nucleation and anchoring at the centrosome are independent processes linked by ninein function. J Cell Sci 2005; 118:1565-75. [PMID: 15784680 DOI: 10.1242/jcs.02302] [Citation(s) in RCA: 223] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The centrosome organizes microtubules by controlling nucleation and anchoring processes. In mammalian cells, subdistal appendages of the mother centriole are major microtubule-anchoring structures of the centrosome. It is not known how newly nucleated microtubules are anchored to these appendages. We show here that ninein, a component of subdistal appendages, localizes to the centriole via its C-terminus and interacts with gamma-tubulin-containing complexes via its N-terminus. Expression of a construct encoding the ninein C-terminus displaced endogenous ninein and the gamma-tubulin ring complex (gamma-TuRC) from the centrosome, leading to microtubule nucleation and anchoring defects. By contrast, expression of a fusion consisting of the N- and C-terminal domains (lacking the central coiled-coil region) displaced endogenous ninein without perturbing gamma-TuRC localization. Accordingly, only anchoring defects were observed in this case. Therefore, expression of this fusion appeared to uncouple microtubule nucleation and anchorage activities at the centrosome. Our results suggest that ninein has a role not only in microtubule anchoring but also in promoting microtubule nucleation by docking the gamma-TuRC at the centrosome. In addition, we show that the gamma-TuRC might not be sufficient to anchor microtubules at the centrosome in the absence of ninein. We therefore propose that ninein constitutes a molecular link between microtubule-nucleation and -anchoring activities at the centrosome.
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Affiliation(s)
- Nathalie Delgehyr
- Institut Curie, Research Section/UMR144 du Centre National de la Recherche Scientifique, 26 rue d'Ulm, 75248 Paris Cedex 05, France
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