1
|
McGillivary RM, Sood P, Hammar K, Marshall WF. The nuclear transport factor CSE1 drives macronuclear volume increase and macronuclear node coalescence in Stentor coeruleus. iScience 2023; 26:107318. [PMID: 37520736 PMCID: PMC10374459 DOI: 10.1016/j.isci.2023.107318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 04/27/2023] [Accepted: 07/04/2023] [Indexed: 08/01/2023] Open
Abstract
Stentor coeruleus provides a unique opportunity to study how cells regulate nuclear shape because its macronucleus undergoes a rapid, dramatic, and developmentally regulated shape change. We found that the volume of the macronucleus increases during coalescence, suggesting an inflation-based mechanism. When the nuclear transport factor, CSE1, is knocked down by RNAi, the shape and volume changes of the macronucleus are attenuated, and nuclear morphology is altered. CSE1 protein undergoes a dynamic relocalization correlated with nuclear shape changes, being mainly cytoplasmic prior to nuclear coalescence, and accumulating inside the macronucleus during coalescence. At the end of regeneration, CSE1 protein levels are reduced as the macronucleus returns to its pre-coalescence volume. We propose a model in which nuclear transport via CSE1 is required to increase the volume of the macronucleus, thereby decreasing the surface-to-volume ratio and driving coalescence of the nodes into a single mass.
Collapse
Affiliation(s)
- Rebecca M. McGillivary
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, USA
| | - Pranidhi Sood
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, USA
| | - Katherine Hammar
- Central Microscopy Facility, Marine Biological Laboratory, Woods Hole, MA, USA
| | - Wallace F. Marshall
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, USA
| |
Collapse
|
2
|
Som S, Paul R. Mechanistic model for nuclear migration in hyphae during mitosis. Phys Rev E 2023; 108:014401. [PMID: 37583222 DOI: 10.1103/physreve.108.014401] [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: 03/02/2023] [Accepted: 06/13/2023] [Indexed: 08/17/2023]
Abstract
Saccharomyces cerevisiae and Candida albicans, the two well-known human pathogens, can be found in all three morphologies, i.e., yeast, pseudohyphae, and true hyphae. The cylindrical daughter-bud (germ tube) grows very long for true hyphae, and the cell cycle is delayed compared to the other two morphologies. The place of the nuclear division is specific for true hyphae determined by the position of the septin ring. However, the septin ring can localize anywhere inside the germ tube, unlike the mother-bud junction in budding yeast. Since the nucleus often migrates a long path in the hyphae, the underlying mechanism must be robust for executing mitosis in a timely manner. We explore the mechanism of nuclear migration through hyphae in light of mechanical interactions between astral microtubules and the cell cortex. We report that proper migration through constricted hyphae requires a large dynein pull applied on the astral microtubules from the hyphal cortex. This is achieved when the microtubules frequently slide along the hyphal cortex so that a large population of dyneins actively participate, pulling on them. Simulation shows timely migration when the dyneins from the mother cortex do not participate in pulling on the microtubules. These findings are robust for long migration and positioning of the nucleus in the germ tube at the septin ring.
Collapse
Affiliation(s)
- Subhendu Som
- Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
| | - Raja Paul
- Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
| |
Collapse
|
3
|
Padilla JR, Ferreira LM, Folker ES. Nuclear movement in multinucleated cells. Development 2022; 149:dev200749. [PMID: 36305464 PMCID: PMC10655921 DOI: 10.1242/dev.200749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Nuclear movement is crucial for the development of many cell types and organisms. Nuclear movement is highly conserved, indicating its necessity for cellular function and development. In addition to mononucleated cells, there are several examples of cells in which multiple nuclei exist within a shared cytoplasm. These multinucleated cells and syncytia have important functions for development and homeostasis. Here, we review a subset of the developmental contexts in which the regulation of the movement and positioning of multiple nuclei are well understood, including pronuclear migration, the Drosophila syncytial blastoderm, the Caenorhabditis elegans hypodermis, skeletal muscle and filamentous fungi. We apply the principles learned from these models to other systems.
Collapse
Affiliation(s)
- Jorel R. Padilla
- Biology Department, Boston College, Chestnut Hill, MA 02467, USA
| | | | - Eric S. Folker
- Biology Department, Boston College, Chestnut Hill, MA 02467, USA
| |
Collapse
|
4
|
Klaus S, Binder P, Kim J, Machado M, Funaya C, Schaaf V, Klaschka D, Kudulyte A, Cyrklaff M, Laketa V, Höfer T, Guizetti J, Becker NB, Frischknecht F, Schwarz US, Ganter M. Asynchronous nuclear cycles in multinucleated Plasmodium falciparum facilitate rapid proliferation. SCIENCE ADVANCES 2022; 8:eabj5362. [PMID: 35353560 PMCID: PMC8967237 DOI: 10.1126/sciadv.abj5362] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 02/10/2022] [Indexed: 05/20/2023]
Abstract
Malaria-causing parasites proliferate within erythrocytes through schizogony, forming multinucleated stages before cellularization. Nuclear multiplication does not follow a strict geometric 2n progression, and each proliferative cycle produces a variable number of progeny. Here, by tracking nuclei and DNA replication, we show that individual nuclei replicate their DNA at different times, despite residing in a shared cytoplasm. Extrapolating from experimental data using mathematical modeling, we provide strong indication that a limiting factor exists, which slows down the nuclear multiplication rate. Consistent with this prediction, our data show that temporally overlapping DNA replication events were significantly slower than partially overlapping or nonoverlapping events. Our findings suggest the existence of evolutionary pressure that selects for asynchronous DNA replication, balancing available resources with rapid pathogen proliferation.
Collapse
Affiliation(s)
- Severina Klaus
- Center for Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany
| | - Patrick Binder
- Institute for Theoretical Physics and BioQuant, Heidelberg University, Heidelberg, Germany
- Theoretical Systems Biology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Juyeop Kim
- Center for Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany
| | - Marta Machado
- Center for Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany
- Graduate Program in Areas of Basic and Applied Biology, Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Charlotta Funaya
- Electron Microscopy Core Facility, Heidelberg University, Heidelberg, Germany
| | - Violetta Schaaf
- Center for Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany
| | - Darius Klaschka
- Center for Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany
| | - Aiste Kudulyte
- Center for Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany
| | - Marek Cyrklaff
- Center for Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany
| | - Vibor Laketa
- Center for Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany
| | - Thomas Höfer
- Theoretical Systems Biology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Julien Guizetti
- Center for Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany
| | - Nils B. Becker
- Theoretical Systems Biology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | | | - Ulrich S. Schwarz
- Institute for Theoretical Physics and BioQuant, Heidelberg University, Heidelberg, Germany
| | - Markus Ganter
- Center for Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany
| |
Collapse
|
5
|
Deshpande O, Telley IA. Nuclear positioning during development: Pushing, pulling and flowing. Semin Cell Dev Biol 2021; 120:10-21. [PMID: 34642103 DOI: 10.1016/j.semcdb.2021.09.020] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Revised: 09/29/2021] [Accepted: 09/30/2021] [Indexed: 01/13/2023]
Abstract
The positioning of the nucleus, the central organelle of the cell, is an active and regulated process crucially linked to cell cycle, differentiation, migration, and polarity. Alterations in positioning have been correlated with cell and tissue function deficiency and genetic or chemical manipulation of nuclear position is embryonic lethal. Nuclear positioning is a precursor for symmetric or asymmetric cell division which is accompanied by fate determination of the daughter cells. Nuclear positioning also plays a key role during early embryonic developmental stages in insects, such as Drosophila, where hundreds of nuclei divide without cytokinesis and are distributed within the large syncytial embryo at roughly regular spacing. While the cytoskeletal elements and the linker proteins to the nucleus are fairly well characterised, including some of the force generating elements driving nuclear movement, there is considerable uncertainty about the biophysical mechanism of nuclear positioning, while the field is debating different force models. In this review, we highlight the current body of knowledge, discuss cell context dependent models of nuclear positioning, and outline open questions.
Collapse
Affiliation(s)
- Ojas Deshpande
- Instituto Gulbenkian de Ciência (IGC), Rua da Quinta Grande 6, 2780-156 Oeiras, Portugal
| | - Ivo A Telley
- Instituto Gulbenkian de Ciência (IGC), Rua da Quinta Grande 6, 2780-156 Oeiras, Portugal.
| |
Collapse
|
6
|
Sporulation in Ashbya gossypii. J Fungi (Basel) 2020; 6:jof6030157. [PMID: 32872517 PMCID: PMC7558398 DOI: 10.3390/jof6030157] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 08/26/2020] [Accepted: 08/28/2020] [Indexed: 12/28/2022] Open
Abstract
Ashbya gossypii is a filamentous ascomycete belonging to the yeast family of Saccharomycetaceae. At the end of its growth phase Ashbya generates abundant amounts of riboflavin and spores that form within sporangia derived from fragmented cellular compartments of hyphae. The length of spores differs within species of the genus. Needle-shaped Ashbya spores aggregate via terminal filaments. A. gossypii is a homothallic fungus which may possess a and α mating types. However, the solo-MATa type strain is self-fertile and sporulates abundantly apparently without the need of prior mating. The central components required for the regulation of sporulation, encoded by IME1, IME2, IME4, KAR4, are conserved with Saccharomyces cerevisiae. Nutrient depletion generates a strong positive signal for sporulation via the cAMP-PKA pathway and SOK2, which is also essential for sporulation. Strong inhibitors of sporulation besides mutations in the central regulatory genes are the addition of exogenous cAMP or the overexpression of the mating type gene MATα2. Sporulation has been dissected using gene-function analyses and global RNA-seq transcriptomics. This revealed a role of Msn2/4, another potential PKA-target, for spore wall formation and a key dual role of the protein A kinase Tpk2 at the onset of sporulation as well as for breaking the dormancy of spores to initiate germination. Recent work has provided an overview of ascus development, regulation of sporulation and spore maturation. This will be summarized in the current review with a focus on the central regulatory genes. Current research and open questions will also be discussed.
Collapse
|
7
|
Manhart A, Azevedo M, Baylies M, Mogilner A. Reverse-engineering forces responsible for dynamic clustering and spreading of multiple nuclei in developing muscle cells. Mol Biol Cell 2020; 31:1802-1814. [PMID: 32129712 PMCID: PMC7521854 DOI: 10.1091/mbc.e19-12-0711] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
How cells position their organelles is a fundamental biological question. During Drosophila embryonic muscle development, multiple nuclei transition from being clustered together to splitting into two smaller clusters to spreading along the myotube’s length. Perturbations of microtubules and motor proteins disrupt this sequence of events. These perturbations do not allow intuiting which molecular forces govern the nuclear positioning; we therefore used computational screening to reverse-engineer and identify these forces. The screen reveals three models. Two suggest that the initial clustering is due to nuclear repulsion from the cell poles, while the third, most robust, model poses that this clustering is due to a short-ranged internuclear attraction. All three models suggest that the nuclear spreading is due to long-ranged internuclear repulsion. We test the robust model quantitatively by comparing it with data from perturbed muscle cells. We also test the model using agent-based simulations with elastic dynamic microtubules and molecular motors. The model predicts that, in longer mammalian myotubes with a large number of nuclei, the spreading stage would be preceded by segregation of the nuclei into a large number of clusters, proportional to the myotube length, with a small average number of nuclei per cluster.
Collapse
Affiliation(s)
- Angelika Manhart
- Mathematics Department, University College London, London WC1H 0AY, UK
| | - Mafalda Azevedo
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065.,Graduate Program in Areas of Basic and Applied Biology (GABBA), Abel Salazar Biomedical Sciences Institute, University of Porto, 4050 Porto, Portugal
| | - Mary Baylies
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065
| | - Alex Mogilner
- Courant Institute for Mathematical Sciences and Department of Biology, New York University, New York, NY 10012
| |
Collapse
|
8
|
The actin capping protein in Aspergillus nidulans enhances dynein function without significantly affecting Arp1 filament assembly. Sci Rep 2018; 8:11419. [PMID: 30061726 PMCID: PMC6065395 DOI: 10.1038/s41598-018-29818-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Accepted: 07/18/2018] [Indexed: 11/08/2022] Open
Abstract
The minus-end-directed microtubule motor cytoplasmic dynein requires the dynactin complex for in vivo functions. The backbone of the vertebrate dynactin complex is the Arp1 (actin-related protein 1) mini-filament whose barbed end binds to the heterodimeric actin capping protein. However, it is unclear whether the capping protein is a dynactin component in lower eukaryotic organisms, especially because it does not appear to be a component of the budding yeast dynactin complex. Here our biochemical data show that the capping protein is a component of the dynactin complex in the filamentous fungus Aspergillus nidulans. Moreover, deletion of the gene encoding capping protein alpha (capA) results in a defect in both nuclear distribution and early-endosome transport, two dynein-mediated processes. However, the defect in either process is less severe than that exhibited by a dynein heavy chain mutant or the ∆p25 mutant of dynactin. In addition, loss of capping protein does not significantly affect the assembly of the dynactin Arp1 filament or the formation of the dynein-dynactin-∆C-HookA (Hook in A. nidulans) complex. These results suggest that fungal capping protein is not important for Arp1 filament assembly but its presence is required for enhancing dynein function in vivo.
Collapse
|
9
|
Pfeifer MA, Khang CH. A nuclear contortionist: the mitotic migration of Magnaporthe oryzae nuclei during plant infection. Mycology 2018; 9:202-210. [PMID: 30181926 PMCID: PMC6115875 DOI: 10.1080/21501203.2018.1482966] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 05/25/2018] [Indexed: 01/22/2023] Open
Abstract
Magnaporthe oryzae is a filamentous fungus, which causes significant destruction to cereal crops worldwide. To infect plant cells, the fungus develops specialised constricted structures such as the penetration peg and the invasive hyphal peg. Live-cell imaging of M. oryzae during plant infection reveals that nuclear migration occurs during intermediate mitosis, in which the nuclear envelope neither completely disassembles nor remains entirely intact. Remarkably, in M. oryzae, mitotic nuclei show incredible malleability while undergoing confined migration through the constricted penetration and invasive hyphal pegs. Here, we review early events in plant infection, discuss intermediate mitosis, and summarise current knowledge of intermediate mitotic nuclear migration in M. oryzae.
Collapse
Affiliation(s)
- Mariel A Pfeifer
- Department of Plant Biology, University of Georgia, Athens, GA30602, USA
| | - Chang Hyun Khang
- Department of Plant Biology, University of Georgia, Athens, GA30602, USA
| |
Collapse
|
10
|
Xiang X. Nuclear movement in fungi. Semin Cell Dev Biol 2017; 82:3-16. [PMID: 29241689 DOI: 10.1016/j.semcdb.2017.10.024] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 10/17/2017] [Accepted: 10/23/2017] [Indexed: 12/22/2022]
Abstract
Nuclear movement within a cell occurs in a variety of eukaryotic organisms including yeasts and filamentous fungi. Fungal molecular genetic studies identified the minus-end-directed microtubule motor cytoplasmic dynein as a critical protein for nuclear movement or orientation of the mitotic spindle contained in the nucleus. Studies in the budding yeast first indicated that dynein anchored at the cortex via its anchoring protein Num1 exerts pulling force on an astral microtubule to orient the anaphase spindle across the mother-daughter axis before nuclear division. Prior to anaphase, myosin V interacts with the plus end of an astral microtubule via Kar9-Bim1/EB1 and pulls the plus end along the actin cables to move the nucleus/spindle close to the bud neck. In addition, pushing or pulling forces generated from cortex-linked polymerization or depolymerization of microtubules drive nuclear movements in yeasts and possibly also in filamentous fungi. In filamentous fungi, multiple nuclei within a hyphal segment undergo dynein-dependent back-and-forth movements and their positioning is also influenced by cytoplasmic streaming toward the hyphal tip. In addition, nuclear movement occurs at various stages of fungal development and fungal infection of plant tissues. This review discusses our current understanding on the mechanisms of nuclear movement in fungal organisms, the importance of nuclear positioning and the regulatory strategies that ensure the proper positioning of nucleus/spindle.
Collapse
Affiliation(s)
- Xin Xiang
- Department of Biochemistry and Molecular Biology, Uniformed Services University of the Health Sciences - F. Edward Hébert School of Medicine, Bethesda, MD, USA.
| |
Collapse
|
11
|
Gibeaux R, Politi AZ, Philippsen P, Nédélec F. Mechanism of nuclear movements in a multinucleated cell. Mol Biol Cell 2017; 28:645-660. [PMID: 28077618 PMCID: PMC5328623 DOI: 10.1091/mbc.e16-11-0806] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 01/04/2017] [Accepted: 01/04/2017] [Indexed: 02/06/2023] Open
Abstract
Multinucleated cells are important in many organisms, but the mechanisms governing the movements of nuclei sharing a common cytoplasm are not understood. In the hyphae of the plant pathogenic fungus Ashbya gossypii, nuclei move back and forth, occasionally bypassing each other, preventing the formation of nuclear clusters. This is essential for genetic stability. These movements depend on cytoplasmic microtubules emanating from the nuclei that are pulled by dynein motors anchored at the cortex. Using three-dimensional stochastic simulations with parameters constrained by the literature, we predict the cortical anchor density from the characteristics of nuclear movements. The model accounts for the complex nuclear movements seen in vivo, using a minimal set of experimentally determined ingredients. Of interest, these ingredients power the oscillations of the anaphase spindle in budding yeast, but in A. gossypii, this system is not restricted to a specific nuclear cycle stage, possibly as a result of adaptation to hyphal growth and multinuclearity.
Collapse
Affiliation(s)
- Romain Gibeaux
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Antonio Z Politi
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Peter Philippsen
- Molecular Microbiology, Biozentrum, University of Basel, CH-4056 Basel, Switzerland
| | - François Nédélec
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| |
Collapse
|
12
|
Dundon SER, Chang SS, Kumar A, Occhipinti P, Shroff H, Roper M, Gladfelter AS. Clustered nuclei maintain autonomy and nucleocytoplasmic ratio control in a syncytium. Mol Biol Cell 2016; 27:2000-7. [PMID: 27193301 PMCID: PMC4927274 DOI: 10.1091/mbc.e16-02-0129] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Accepted: 05/09/2016] [Indexed: 01/14/2023] Open
Abstract
Nuclei in syncytia found in fungi, muscles, and tumors can behave independently despite cytoplasmic translation and the homogenizing potential of diffusion. We use a dynactin mutant strain of the multinucleate fungus Ashbya gossypii with highly clustered nuclei to assess the relative contributions of nucleus and cytoplasm to nuclear autonomy. Remarkably, clustered nuclei maintain cell cycle and transcriptional autonomy; therefore some sources of nuclear independence function even with minimal cytosol insulating nuclei. In both nuclear clusters and among evenly spaced nuclei, a nucleus' transcriptional activity dictates local cytoplasmic contents, as assessed by the localization of several cyclin mRNAs. Thus nuclear activity is a central determinant of the local cytoplasm in syncytia. Of note, we found that the number of nuclei per unit cytoplasm was identical in the mutant to that in wild-type cells, despite clustered nuclei. This work demonstrates that nuclei maintain autonomy at a submicrometer scale and simultaneously maintain a normal nucleocytoplasmic ratio across a syncytium up to the centimeter scale.
Collapse
Affiliation(s)
| | - Shyr-Shea Chang
- Departments of Mathematics and Biomathematics, University of California, Los Angeles, Los Angeles, CA 90095
| | - Abhishek Kumar
- Section on High Resolution Optical Imaging, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892
| | | | - Hari Shroff
- Section on High Resolution Optical Imaging, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892
| | - Marcus Roper
- Departments of Mathematics and Biomathematics, University of California, Los Angeles, Los Angeles, CA 90095
| | - Amy S Gladfelter
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755 The Bell Center, Marine Biological Laboratory, Woods Hole, MA 02543
| |
Collapse
|
13
|
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: 1.1] [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.
Collapse
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
| |
Collapse
|
14
|
Xiang X, Qiu R, Yao X, Arst HN, Peñalva MA, Zhang J. Cytoplasmic dynein and early endosome transport. Cell Mol Life Sci 2015; 72:3267-80. [PMID: 26001903 DOI: 10.1007/s00018-015-1926-y] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Revised: 05/04/2015] [Accepted: 05/05/2015] [Indexed: 11/25/2022]
Abstract
Microtubule-based distribution of organelles/vesicles is crucial for the function of many types of eukaryotic cells and the molecular motor cytoplasmic dynein is required for transporting a variety of cellular cargos toward the microtubule minus ends. Early endosomes represent a major cargo of dynein in filamentous fungi, and dynein regulators such as LIS1 and the dynactin complex are both required for early endosome movement. In fungal hyphae, kinesin-3 and dynein drive bi-directional movements of early endosomes. Dynein accumulates at microtubule plus ends; this accumulation depends on kinesin-1 and dynactin, and it is important for early endosome movements towards the microtubule minus ends. The physical interaction between dynein and early endosome requires the dynactin complex, and in particular, its p25 component. The FTS-Hook-FHIP (FHF) complex links dynein-dynactin to early endosomes, and within the FHF complex, Hook interacts with dynein-dynactin, and Hook-early endosome interaction depends on FHIP and FTS.
Collapse
Affiliation(s)
- Xin Xiang
- Department of Biochemistry and Molecular Biology, F. Edward Hébert School of Medicine, The Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD, 20814, USA,
| | | | | | | | | | | |
Collapse
|
15
|
Functional Significance of Anastomosis in Arbuscular Mycorrhizal Networks. ECOLOGICAL STUDIES 2015. [DOI: 10.1007/978-94-017-7395-9_2] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
|
16
|
Yao X, Wang X, Xiang X. FHIP and FTS proteins are critical for dynein-mediated transport of early endosomes in Aspergillus. Mol Biol Cell 2014; 25:2181-9. [PMID: 24870033 PMCID: PMC4091831 DOI: 10.1091/mbc.e14-04-0873] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The minus end-directed microtubule motor cytoplasmic dynein transports various cellular cargoes, including early endosomes, but how dynein binds to its cargo remains unclear. Recently fungal Hook homologues were found to link dynein to early endosomes for their transport. Here we identified FhipA in Aspergillus nidulans as a key player for HookA (A. nidulans Hook) function via a genome-wide screen for mutants defective in early-endosome distribution. The human homologue of FhipA, FHIP, is a protein in the previously discovered FTS/Hook/FHIP (FHF) complex, which contains, besides FHIP and Hook proteins, Fused Toes (FTS). Although this complex was not previously shown to be involved in dynein-mediated transport, we show here that loss of either FhipA or FtsA (A. nidulans FTS homologue) disrupts HookA-early endosome association and inhibits early endosome movement. Both FhipA and FtsA associate with early endosomes, and interestingly, while FtsA-early endosome association requires FhipA and HookA, FhipA-early endosome association is independent of HookA and FtsA. Thus FhipA is more directly linked to early endosomes than HookA and FtsA. However, in the absence of HookA or FtsA, FhipA protein level is significantly reduced. Our results indicate that all three proteins in the FtsA/HookA/FhipA complex are important for dynein-mediated early endosome movement.
Collapse
Affiliation(s)
- Xuanli Yao
- Department of Biochemistry and Molecular Biology, Uniformed Services University of the Health Sciences-F. Edward Hébert School of Medicine, Bethesda, MD 20814
| | - Xiangfeng Wang
- School of Plant Sciences, University of Arizona, Tucson, AZ 85721
| | - Xin Xiang
- Department of Biochemistry and Molecular Biology, Uniformed Services University of the Health Sciences-F. Edward Hébert School of Medicine, Bethesda, MD 20814
| |
Collapse
|
17
|
Anderson CA, Eser U, Korndorf T, Borsuk ME, Skotheim JM, Gladfelter AS. Nuclear repulsion enables division autonomy in a single cytoplasm. Curr Biol 2013; 23:1999-2010. [PMID: 24094857 PMCID: PMC4085259 DOI: 10.1016/j.cub.2013.07.076] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Revised: 05/31/2013] [Accepted: 07/23/2013] [Indexed: 02/08/2023]
Abstract
BACKGROUND Current models of cell-cycle control, based on classic studies of fused cells, predict that nuclei in a shared cytoplasm respond to the same CDK activities to undergo synchronous cycling. However, synchrony is rarely observed in naturally occurring syncytia, such as the multinucleate fungus Ashbya gossypii. In this system, nuclei divide asynchronously, raising the question of how nuclear timing differences are maintained despite sharing a common milieu. RESULTS We observe that neighboring nuclei are highly variable in division-cycle duration and that neighbors repel one another to space apart and demarcate their own cytoplasmic territories. The size of these territories increases as a nucleus approaches mitosis and can influence cycling rates. This nonrandom nuclear spacing is regulated by microtubules and is required for nuclear asynchrony, as nuclei that transiently come in very close proximity will partially synchronize. Sister nuclei born of the same mitosis are generally not persistent neighbors over their lifetimes yet remarkably retain similar division cycle times. This indicates that nuclei carry a memory of their birth state that influences their division timing and supports that nuclei subdivide a common cytosol into functionally distinct yet mobile compartments. CONCLUSIONS These findings support that nuclei use cytoplasmic microtubules to establish "cells within cells." Individual compartments appear to push against one another to compete for cytoplasmic territory and insulate the division cycle. This provides a mechanism by which syncytial nuclei can spatially organize cell-cycle signaling and suggests size control can act in a system without physical boundaries.
Collapse
Affiliation(s)
- Cori A. Anderson
- Department of Biological Sciences Dartmouth College Hanover, NH 03755
| | - Umut Eser
- Department of Applied Physics Stanford University Stanford, CA 94305
| | - Therese Korndorf
- Department of Biological Sciences Dartmouth College Hanover, NH 03755
| | - Mark E. Borsuk
- Thayer School of Engineering Dartmouth College Hanover, NH 03755
| | - Jan M. Skotheim
- Department of Biology Stanford University Stanford, CA 94305
| | - Amy S. Gladfelter
- Department of Biological Sciences Dartmouth College Hanover, NH 03755
| |
Collapse
|
18
|
Organization of organelles within hyphae of Ashbya gossypii revealed by electron tomography. EUKARYOTIC CELL 2013; 12:1423-32. [PMID: 23771903 DOI: 10.1128/ec.00106-13] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Ashbya gossypii grows as multinucleated and constantly elongating hyphae. Nuclei are in continuous forward and backward motion, also move during mitosis, and frequently bypass each other. Whereas these nuclear movements are well documented, comparatively little is known about the density and morphology of organelles which very likely influence these movements. To understand the three-dimensional subcellular organization of hyphae at high resolution, we performed large-scale electron tomography of the tip regions in A. gossypii. Here, we present a comprehensive space-filling model in which most membrane-limited organelles including nuclei, mitochondria, endosomes, multivesicular bodies, vacuoles, autophagosomes, peroxisomes, and vesicles are modeled. Nuclei revealed different morphologies and protrusions filled by the nucleolus. Mitochondria are very abundant and form a tubular network with a polarized spherical fraction. The organelles of the degradative pathways show a clustered organization. By analyzing vesicle-like bodies, we identified three size classes of electron-dense vesicles (∼200, ∼150, and ∼100 nm) homogeneously distributed in the cytoplasm which most likely represent peroxisomes. Finally, coated and uncoated vesicles with approximately 40-nm diameters show a polarized distribution toward the hyphal tip with the coated vesicles preferentially localizing at the hyphal periphery.
Collapse
|
19
|
Gibeaux R, Lang C, Politi AZ, Jaspersen SL, Philippsen P, Antony C. Electron tomography of the microtubule cytoskeleton in multinucleated hyphae of Ashbya gossypii. J Cell Sci 2012; 125:5830-9. [DOI: 10.1242/jcs.111005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
We report about the mechanistic basis guiding the migration pattern of multiple nuclei in hyphae of Ashbya gossypii. Using electron tomography we reconstructed the cytoplasmic microtubule (cMT) cytoskeleton in three tip regions with a total of 13 nuclei and also the spindle microtubules of four mitotic nuclei. Each spindle pole body (SPB) nucleates three cMTs and most cMTs above a certain length are growing according to their plus-end structure. Long cMTs closely align for several microns along the cortex, presumably marking regions where dynein generates pulling forces on nuclei. Close proximity between cMTs emanating from adjacent nuclei was not observed. The majority of nuclei carry duplicated side-by-side SPBs, which together emanate an average of six cMTs, in most cases in opposite orientation with respect to the hyphal growth axis. Such cMT arrays explain why many nuclei undergo short-range back and forth movements. Only occasionally, do all six cMTs orient in one direction, a precondition for long-range nuclear bypassing. Following mitosis, daughter nuclei carry a single SPB with three cMTs. The increased probability that all three cMTs orient in one direction explains the high rate of nuclear bypassing observed in these nuclei. The A. gossypii mitotic spindle was found to be structurally similar to that of Saccharomyces cerevisiae in terms of nuclear microtubule (nMT) number, length distribution and three-dimensional organization even though the two organisms differ significantly in chromosome number. Our results suggest that in A. gossypii two nMTs attach to each kinetochore and not only one like in S. cerevisiae.
Collapse
|
20
|
Steinberg G. Motors in fungal morphogenesis: cooperation versus competition. Curr Opin Microbiol 2011; 14:660-7. [DOI: 10.1016/j.mib.2011.09.013] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2011] [Accepted: 09/27/2011] [Indexed: 10/15/2022]
|