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Gräf R, Batsios P, Grafe M, Meyer I, Mitic K. Nuclear Envelope Dynamics in Dictyostelium Amoebae. Cells 2025; 14:186. [PMID: 39936978 PMCID: PMC11816917 DOI: 10.3390/cells14030186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2024] [Revised: 01/22/2025] [Accepted: 01/23/2025] [Indexed: 02/13/2025] Open
Abstract
In the last decades, the study of many nuclear envelope components in Dictyostelium amoebae has revealed conserved mechanisms of nuclear envelope dynamics that root back unexpectedly deep into the eukaryotic tree of life. In this review, we describe the state of the art in nuclear envelope research in this organism starting from early work on nuclear pore complexes to characterization of the first true lamin in a non-metazoan organism and its associated nuclear envelope transmembrane proteins, such as the HeH-family protein Src1 and the LINC complex protein Sun1. We also describe the dynamic processes during semi-closed mitosis, including centrosome insertion into the nuclear envelope, and processes involved in the restoration of nuclear envelope permeability around mitotic exit and compare them to the situation in cells with open or fully closed mitosis.
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Affiliation(s)
- Ralph Gräf
- Department of Cell Biology, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam-Golm, Germany; (M.G.); (I.M.); (K.M.)
| | - Petros Batsios
- Sigma-Aldrich Chemie GmbH, Eschenstraße 5, 82024 Taufkirchen, Germany;
| | - Marianne Grafe
- Department of Cell Biology, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam-Golm, Germany; (M.G.); (I.M.); (K.M.)
| | - Irene Meyer
- Department of Cell Biology, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam-Golm, Germany; (M.G.); (I.M.); (K.M.)
| | - Kristina Mitic
- Department of Cell Biology, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam-Golm, Germany; (M.G.); (I.M.); (K.M.)
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2
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Walsh ME, King GA, Ünal E. Not just binary: embracing the complexity of nuclear division dynamics. Nucleus 2024; 15:2360601. [PMID: 38842147 PMCID: PMC11164224 DOI: 10.1080/19491034.2024.2360601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Accepted: 05/22/2024] [Indexed: 06/07/2024] Open
Abstract
Cell division presents a challenge for eukaryotic cells: how can chromosomes effectively segregate within the confines of a membranous nuclear compartment? Different organisms have evolved diverse solutions by modulating the degree of nuclear compartmentalization, ranging from complete nuclear envelope breakdown to complete maintenance of nuclear compartmentalization via nuclear envelope expansion. Many intermediate forms exist between these extremes, suggesting that nuclear dynamics during cell division are surprisingly plastic. In this review, we highlight the evolutionary diversity of nuclear divisions, focusing on two defining characteristics: (1) chromosome compartmentalization and (2) nucleocytoplasmic transport. Further, we highlight recent evidence that nuclear behavior during division can vary within different cellular contexts in the same organism. The variation observed within and between organisms underscores the dynamic evolution of nuclear divisions tailored to specific contexts and cellular requirements. In-depth investigation of diverse nuclear divisions will enhance our understanding of the nucleus, both in physiological and pathological states.
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Affiliation(s)
- Madison E. Walsh
- Department of Molecular and Cell Biology, Barker Hall, University of California, Berkeley, CA, USA
| | - Grant A. King
- Department of Molecular and Cell Biology, Barker Hall, University of California, Berkeley, CA, USA
| | - Elçin Ünal
- Department of Molecular and Cell Biology, Barker Hall, University of California, Berkeley, CA, USA
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3
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Shi R, Lin X. Illuminating the Cryptococcus neoformans species complex: unveiling intracellular structures with fluorescent-protein-based markers. Genetics 2024; 227:iyae059. [PMID: 38752295 PMCID: PMC11228865 DOI: 10.1093/genetics/iyae059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Accepted: 04/06/2024] [Indexed: 07/09/2024] Open
Abstract
Cryptococcus neoformans is a fungal pathogen of the top critical priority recognized by the World Health Organization. This clinically important fungus also serves as a eukaryotic model organism. A variety of resources have been generated to facilitate investigation of the C. neoformans species complex, including congenic pairs, well-annotated genomes, genetic editing tools, and gene deletion sets. Here, we generated a set of strains with all major organelles fluorescently marked. We tested short organelle-specific targeting sequences and successfully labeled the following organelles by fusing the targeting sequences with a fluorescence protein: the plasma membrane, the nucleus, the peroxisome, and the mitochondrion. We used native cryptococcal Golgi and late endosomal proteins fused with a fluorescent protein to label these two organelles. These fluorescence markers were verified via colocalization using organelle-specific dyes. All the constructs for the fluorescent protein tags were integrated in an intergenic safe haven region. These organelle-marked strains were examined for growth and various phenotypes. We demonstrated that these tagged strains could be employed to track cryptococcal interaction with the host in phagocytosis assays. These strains also allowed us to discover remarkable differences in the dynamics of proteins targeted to different organelles during sexual reproduction. Additionally, we revealed that "dormant" spores transcribed and synthesized their own proteins and trafficked the proteins to the appropriate subcellular compartments, demonstrating that spores are metabolically active. We anticipate that these newly generated fluorescent markers will greatly facilitate further investigation of cryptococcal biology and pathogenesis.
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Affiliation(s)
- Ran Shi
- Department of Microbiology, University of Georgia, Athens, GA 30602, USA
| | - Xiaorong Lin
- Department of Microbiology, University of Georgia, Athens, GA 30602, USA
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4
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Petrucco CA, Crocker AW, D’Alessandro A, Medina EM, Gorman O, McNeill J, Gladfelter AS, Lew DJ. Tools for live-cell imaging of cytoskeletal and nuclear behavior in the unconventional yeast, Aureobasidium pullulans. Mol Biol Cell 2024; 35:br10. [PMID: 38446617 PMCID: PMC11064661 DOI: 10.1091/mbc.e23-10-0388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 02/07/2024] [Accepted: 02/27/2024] [Indexed: 03/08/2024] Open
Abstract
Aureobasidium pullulans is a ubiquitous fungus with a wide variety of morphologies and growth modes including "typical" single-budding yeast, and interestingly, larger multinucleate yeast than can make multiple buds in a single cell cycle. The study of A. pullulans promises to uncover novel cell biology, but currently tools are lacking to achieve this goal. Here, we describe initial components of a cell biology toolkit for A. pullulans, which is used to express and image fluorescent probes for nuclei as well as components of the cytoskeleton. These tools allowed live-cell imaging of the multinucleate and multibudding cycles, revealing highly synchronous mitoses in multinucleate yeast that occur in a semiopen manner with an intact but permeable nuclear envelope. These findings open the door to using this ubiquitous polyextremotolerant fungus as a model for evolutionary cell biology.
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Affiliation(s)
- Claudia A. Petrucco
- Department of Pharmacology and Cancer Biology, Duke University, Durham, NC 27710
| | - Alex W. Crocker
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC 27599
| | - Alec D’Alessandro
- Department of Pharmacology and Cancer Biology, Duke University, Durham, NC 27710
| | - Edgar M. Medina
- Department of Biology, University of Massachusetts, Amherst, MA 01003
| | - Olivia Gorman
- Department of Pharmacology and Cancer Biology, Duke University, Durham, NC 27710
| | - Jessica McNeill
- Department of Pharmacology and Cancer Biology, Duke University, Durham, NC 27710
| | | | - Daniel J. Lew
- Department of Pharmacology and Cancer Biology, Duke University, Durham, NC 27710
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5
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Martínez-Andrade JM, Roberson RW, Riquelme M. A bird's-eye view of the endoplasmic reticulum in filamentous fungi. Microbiol Mol Biol Rev 2024; 88:e0002723. [PMID: 38372526 PMCID: PMC10966943 DOI: 10.1128/mmbr.00027-23] [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: 02/20/2024] Open
Abstract
SUMMARYThe endoplasmic reticulum (ER) is one of the most extensive organelles in eukaryotic cells. It performs crucial roles in protein and lipid synthesis and Ca2+ homeostasis. Most information on ER types, functions, organization, and domains comes from studies in uninucleate animal, plant, and yeast cells. In contrast, there is limited information on the multinucleate cells of filamentous fungi, i.e., hyphae. We provide an analytical review of existing literature to categorize different types of ER described in filamentous fungi while emphasizing the research techniques and markers used. Additionally, we identify the knowledge gaps that need to be resolved better to understand the structure-function correlation of ER in filamentous fungi. Finally, advanced technologies that can provide breakthroughs in understanding the ER in filamentous fungi are discussed.
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Affiliation(s)
- Juan M. Martínez-Andrade
- Department of Microbiology, Centro de Investigación Científica y Educación Superior de Ensenada (CICESE), Ensenada, Baja California, Mexico
| | | | - Meritxell Riquelme
- Department of Microbiology, Centro de Investigación Científica y Educación Superior de Ensenada (CICESE), Ensenada, Baja California, Mexico
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6
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Zhang J, Qiu R, Bieger BD, Oakley CE, Oakley BR, Egan MJ, Xiang X. Aspergillus SUMOylation mutants exhibit chromosome segregation defects including chromatin bridges. Genetics 2023; 225:iyad169. [PMID: 37724751 PMCID: PMC10697819 DOI: 10.1093/genetics/iyad169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 08/29/2023] [Accepted: 09/07/2023] [Indexed: 09/21/2023] Open
Abstract
Functions of protein SUMOylation remain incompletely understood in different cell types. Via forward genetics, here we identified ubaBQ247*, a loss-of-function mutation in a SUMO activation enzyme UbaB in the filamentous fungus Aspergillus nidulans. The ubaBQ247*, ΔubaB, and ΔsumO mutants all produce abnormal chromatin bridges, indicating the importance of SUMOylation in the completion of chromosome segregation. The bridges are enclosed by nuclear membrane containing peripheral nuclear pore complex proteins that normally get dispersed during mitosis, and the bridges are also surrounded by cytoplasmic microtubules typical of interphase cells. Time-lapse sequences further indicate that most bridges persist through interphase prior to the next mitosis, and anaphase chromosome segregation can produce new bridges that persist into the next interphase. When the first mitosis happens at a higher temperature of 42°C, SUMOylation deficiency produces not only chromatin bridges but also many abnormally shaped single nuclei that fail to divide. UbaB-GFP localizes to interphase nuclei just like the previously studied SumO-GFP, but the nuclear signals disappear during mitosis when the nuclear pores are partially open, and the signals reappear after mitosis. The nuclear localization is consistent with many SUMO targets being nuclear proteins. Finally, although the budding yeast SUMOylation machinery interacts with LIS1, a protein critical for dynein activation, loss of SUMOylation does not cause any obvious defect in dynein-mediated transport of nuclei and early endosomes, indicating that SUMOylation is unnecessary for dynein activation in A. nidulans.
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Affiliation(s)
- Jun Zhang
- Department of Biochemistry and Molecular Biology, The Uniformed Services University of the Health Sciences-F. Edward Hébert School of Medicine, Bethesda, MD 20814, USA
| | - Rongde Qiu
- Department of Biochemistry and Molecular Biology, The Uniformed Services University of the Health Sciences-F. Edward Hébert School of Medicine, Bethesda, MD 20814, USA
| | - Baronger D Bieger
- Department of Entomology and Plant Pathology, University of Arkansas Systems Division of Agriculture, Fayetteville, AR 72701, USA
| | - C Elizabeth Oakley
- Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66045, USA
| | - Berl R Oakley
- Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66045, USA
| | - Martin J Egan
- Department of Entomology and Plant Pathology, University of Arkansas Systems Division of Agriculture, Fayetteville, AR 72701, USA
| | - Xin Xiang
- Department of Biochemistry and Molecular Biology, The Uniformed Services University of the Health Sciences-F. Edward Hébert School of Medicine, Bethesda, MD 20814, USA
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7
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Padilla‐Mejia NE, Field MC. Evolutionary, structural and functional insights in nuclear organisation and nucleocytoplasmic transport in trypanosomes. FEBS Lett 2023; 597:2501-2518. [PMID: 37789516 PMCID: PMC10953052 DOI: 10.1002/1873-3468.14747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 09/18/2023] [Accepted: 09/19/2023] [Indexed: 10/05/2023]
Abstract
One of the remarkable features of eukaryotes is the nucleus, delimited by the nuclear envelope (NE), a complex structure and home to the nuclear lamina and nuclear pore complex (NPC). For decades, these structures were believed to be mainly architectural elements and, in the case of the NPC, simply facilitating nucleocytoplasmic trafficking. More recently, the critical roles of the lamina, NPC and other NE constituents in genome organisation, maintaining chromosomal domains and regulating gene expression have been recognised. Importantly, mutations in genes encoding lamina and NPC components lead to pathogenesis in humans, while pathogenic protozoa disrupt the progression of normal development and expression of pathogenesis-related genes. Here, we review features of the lamina and NPC across eukaryotes and discuss how these elements are structured in trypanosomes, protozoa of high medical and veterinary importance, highlighting lineage-specific and conserved aspects of nuclear organisation.
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Affiliation(s)
| | - Mark C. Field
- School of Life SciencesUniversity of DundeeUK
- Institute of Parasitology, Biology CentreCzech Academy of SciencesČeské BudějoviceCzechia
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8
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Panstruga R, Antonin W, Lichius A. Looking outside the box: a comparative cross-kingdom view on the cell biology of the three major lineages of eukaryotic multicellular life. Cell Mol Life Sci 2023; 80:198. [PMID: 37418047 PMCID: PMC10329083 DOI: 10.1007/s00018-023-04843-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 06/16/2023] [Accepted: 06/17/2023] [Indexed: 07/08/2023]
Abstract
Many cell biological facts that can be found in dedicated scientific textbooks are based on findings originally made in humans and/or other mammals, including respective tissue culture systems. They are often presented as if they were universally valid, neglecting that many aspects differ-in part considerably-between the three major kingdoms of multicellular eukaryotic life, comprising animals, plants and fungi. Here, we provide a comparative cross-kingdom view on the basic cell biology across these lineages, highlighting in particular essential differences in cellular structures and processes between phyla. We focus on key dissimilarities in cellular organization, e.g. regarding cell size and shape, the composition of the extracellular matrix, the types of cell-cell junctions, the presence of specific membrane-bound organelles and the organization of the cytoskeleton. We further highlight essential disparities in important cellular processes such as signal transduction, intracellular transport, cell cycle regulation, apoptosis and cytokinesis. Our comprehensive cross-kingdom comparison emphasizes overlaps but also marked differences between the major lineages of the three kingdoms and, thus, adds to a more holistic view of multicellular eukaryotic cell biology.
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Affiliation(s)
- Ralph Panstruga
- Unit of Plant Molecular Cell Biology, Institute for Biology I, RWTH Aachen University, Worringerweg 1, 52056, Aachen, Germany.
| | - Wolfram Antonin
- Institute of Biochemistry and Molecular Cell Biology, Medical School, RWTH Aachen University, 52074, Aachen, Germany
| | - Alexander Lichius
- inncellys GmbH, Dorfstrasse 20/3, 6082, Patsch, Austria
- Department of Microbiology, University of Innsbruck, Technikerstrasse 25, 6020, Innsbruck, Austria
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9
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Kakizaki T, Abe H, Kotouge Y, Matsubuchi M, Sugou M, Honma C, Tsukuta K, Satoh S, Shioya T, Nakamura H, Cannon KS, Woods BL, Gladfelter A, Takeshita N, Muraguchi H. Live-cell imaging of septins and cell polarity proteins in the growing dikaryotic vegetative hypha of the model mushroom Coprinopsis cinerea. Sci Rep 2023; 13:10132. [PMID: 37349479 PMCID: PMC10287680 DOI: 10.1038/s41598-023-37115-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Accepted: 06/15/2023] [Indexed: 06/24/2023] Open
Abstract
The developmental biology underlying the morphogenesis of mushrooms remains poorly understood despite the essential role of fungi in the terrestrial environment and global carbon cycle. The mushroom Coprinopsis cinerea is a leading model system for the molecular and cellular basis of fungal morphogenesis. The dikaryotic vegetative hyphae of this fungus grow by tip growth with clamp cell formation, conjugate nuclear division, septation, subapical peg formation, and fusion of the clamp cell to the peg. Studying these processes provides many opportunities to gain insights into fungal cell morphogenesis. Here, we report the dynamics of five septins, as well as the regulators CcCla4, CcSpa2, and F-actin, visualized by tagging with fluorescent proteins, EGFP, PA-GFP or mCherry, in the growing dikaryotic vegetative hyphae. We also observed the nuclei using tagged Sumo proteins and histone H1. The five septins colocalized at the hyphal tip in the shape of a dome with a hole (DwH). CcSpa2-EGFP signals were observed in the hole, while CcCla4 signals were observed as the fluctuating dome at the hyphal tip. Before septation, CcCla4-EGFP was also occasionally recruited transiently around the future septum site. Fluorescent protein-tagged septins and F-actin together formed a contractile ring at the septum site. These distinct specialized growth machineries at different sites of dikaryotic vegetative hyphae provide a foundation to explore the differentiation program of various types of cells required for fruiting body formation.
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Affiliation(s)
- Tetsuya Kakizaki
- Department of Biotechnology, Faculty of Bioresource Sciences, Akita Prefectural University, Shimoshinjo-nakano, Akita, 010-0195, Japan
| | - Haruki Abe
- Department of Biotechnology, Faculty of Bioresource Sciences, Akita Prefectural University, Shimoshinjo-nakano, Akita, 010-0195, Japan
| | - Yuuka Kotouge
- Department of Biotechnology, Faculty of Bioresource Sciences, Akita Prefectural University, Shimoshinjo-nakano, Akita, 010-0195, Japan
| | - Mitsuki Matsubuchi
- Department of Biotechnology, Faculty of Bioresource Sciences, Akita Prefectural University, Shimoshinjo-nakano, Akita, 010-0195, Japan
| | - Mayu Sugou
- Department of Biotechnology, Faculty of Bioresource Sciences, Akita Prefectural University, Shimoshinjo-nakano, Akita, 010-0195, Japan
| | - Chiharu Honma
- Department of Biotechnology, Faculty of Bioresource Sciences, Akita Prefectural University, Shimoshinjo-nakano, Akita, 010-0195, Japan
| | - Kouki Tsukuta
- Department of Biotechnology, Faculty of Bioresource Sciences, Akita Prefectural University, Shimoshinjo-nakano, Akita, 010-0195, Japan
| | - Souichi Satoh
- Department of Biotechnology, Faculty of Bioresource Sciences, Akita Prefectural University, Shimoshinjo-nakano, Akita, 010-0195, Japan
| | - Tatsuhiro Shioya
- Department of Biotechnology, Faculty of Bioresource Sciences, Akita Prefectural University, Shimoshinjo-nakano, Akita, 010-0195, Japan
| | - Hiroe Nakamura
- Department of Biotechnology, Faculty of Bioresource Sciences, Akita Prefectural University, Shimoshinjo-nakano, Akita, 010-0195, Japan
| | - Kevin S Cannon
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Benjamin L Woods
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Amy Gladfelter
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Cell Biology, Duke University, Durham, USA
| | - Norio Takeshita
- Microbiology Research Center for Sustainability (MiCS), Faculty of Life and Environmental Sciences, University of Tsukuba, Tennodai 1-1-1, Tsukuba, 305-8572, Japan
| | - Hajime Muraguchi
- Department of Biotechnology, Faculty of Bioresource Sciences, Akita Prefectural University, Shimoshinjo-nakano, Akita, 010-0195, Japan.
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Thomas L, Taleb Ismail B, Askjaer P, Seydoux G. Nucleoporin foci are stress-sensitive condensates dispensable for C. elegans nuclear pore assembly. EMBO J 2023:e112987. [PMID: 37254647 DOI: 10.15252/embj.2022112987] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 05/02/2023] [Accepted: 05/10/2023] [Indexed: 06/01/2023] Open
Abstract
Nucleoporins (Nups) assemble nuclear pores that form the permeability barrier between nucleoplasm and cytoplasm. Nucleoporins also localize in cytoplasmic foci proposed to function as pore pre-assembly intermediates. Here, we characterize the composition and incidence of cytoplasmic Nup foci in an intact animal, C. elegans. We find that, in young non-stressed animals, Nup foci only appear in developing sperm, oocytes and embryos, tissues that express high levels of nucleoporins. The foci are condensates of highly cohesive FG repeat-containing nucleoporins (FG-Nups), which are maintained near their solubility limit in the cytoplasm by posttranslational modifications and chaperone activity. Only a minor fraction of FG-Nup molecules concentrate in Nup foci, which dissolve during M phase and are dispensable for nuclear pore assembly. Nucleoporin condensation is enhanced by stress and advancing age, and overexpression of a single FG-Nup in post-mitotic neurons is sufficient to induce ectopic condensation and organismal paralysis. We speculate that Nup foci are non-essential and potentially toxic condensates whose assembly is actively suppressed in healthy cells.
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Affiliation(s)
- Laura Thomas
- HHMI and Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Basma Taleb Ismail
- HHMI and Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Peter Askjaer
- Andalusian Center for Developmental Biology (CABD), CSIC/JA/Universidad Pablo de Olavide, Seville, Spain
| | - Geraldine Seydoux
- HHMI and Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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11
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Mitic K, Meyer I, Gräf R, Grafe M. Temporal Changes in Nuclear Envelope Permeability during Semi-Closed Mitosis in Dictyostelium Amoebae. Cells 2023; 12:1380. [PMID: 37408214 DOI: 10.3390/cells12101380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 05/10/2023] [Accepted: 05/11/2023] [Indexed: 07/07/2023] Open
Abstract
The Amoebozoan Dictyostelium discoideum exhibits a semi-closed mitosis in which the nuclear membranes remain intact but become permeabilized to allow tubulin and spindle assembly factors to access the nuclear interior. Previous work indicated that this is accomplished at least by partial disassembly of nuclear pore complexes (NPCs). Further contributions by the insertion process of the duplicating, formerly cytosolic, centrosome into the nuclear envelope and nuclear envelope fenestrations forming around the central spindle during karyokinesis were discussed. We studied the behavior of several Dictyostelium nuclear envelope, centrosomal, and nuclear pore complex (NPC) components tagged with fluorescence markers together with a nuclear permeabilization marker (NLS-TdTomato) by live-cell imaging. We could show that permeabilization of the nuclear envelope during mitosis occurs in synchrony with centrosome insertion into the nuclear envelope and partial disassembly of nuclear pore complexes. Furthermore, centrosome duplication takes place after its insertion into the nuclear envelope and after initiation of permeabilization. Restoration of nuclear envelope integrity usually occurs long after re-assembly of NPCs and cytokinesis has taken place and is accompanied by a concentration of endosomal sorting complex required for transport (ESCRT) components at both sites of nuclear envelope fenestration (centrosome and central spindle).
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Affiliation(s)
- Kristina Mitic
- Department of Cell Biology, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam, Germany
| | - Irene Meyer
- Department of Cell Biology, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam, Germany
| | - Ralph Gräf
- Department of Cell Biology, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam, Germany
| | - Marianne Grafe
- Department of Cell Biology, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam, Germany
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12
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Zhang J, Qiu R, Bieger BD, Oakley CE, Oakley BR, Egan MJ, Xiang X. Aspergillus SUMOylation mutants have normal dynein function but exhibit chromatin bridges. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.16.537086. [PMID: 37131833 PMCID: PMC10153134 DOI: 10.1101/2023.04.16.537086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Functions of protein SUMOylation remain incompletely understood in different cell types. The budding yeast SUMOylation machinery interacts with LIS1, a protein critical for dynein activation, but dynein-pathway components were not identified as SUMO-targets in the filamentous fungus Aspergillus nidulans. Via A. nidulans forward genetics, here we identified ubaBQ247*, a loss-of-function mutation in a SUMO-activation enzyme UbaB. Colonies of the ubaBQ247*, ΔubaB and ΔsumO mutants looked similar and less healthy than the wild-type colony. In these mutants, about 10% of nuclei are connected by abnormal chromatin bridges, indicating the importance of SUMOylation in the completion of chromosome segregation. Nuclei connected by chromatin bridges are mostly in interphase, suggesting that these bridges do not prevent cell-cycle progression. UbaB-GFP localizes to interphase nuclei just like the previously studied SumO-GFP, but the nuclear signals disappear during mitosis when the nuclear pores are partially open, and the signals reappear after mitosis. The nuclear localization is consistent with many SUMO-targets being nuclear proteins, for example, topoisomerase II whose SUMOylation defect gives rise to chromatin bridges in mammalian cells. Unlike in mammalian cells, however, loss of SUMOylation in A. nidulans does not apparently affect the metaphase-to-anaphase transition, further highlighting differences in the requirements of SUMOylation in different cell types. Finally, loss of UbaB or SumO does not affect dynein- and LIS1-mediated early-endosome transport, indicating that SUMOylation is unnecessary for dynein or LIS1 function in A. nidulans.
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Affiliation(s)
- Jun Zhang
- Department of Biochemistry and Molecular Biology, The Uniformed Services University of the Health Sciences- F. Edward Hébert School of Medicine, Bethesda, Maryland 20814, USA
| | - Rongde Qiu
- Department of Biochemistry and Molecular Biology, The Uniformed Services University of the Health Sciences- F. Edward Hébert School of Medicine, Bethesda, Maryland 20814, USA
| | - Baronger D. Bieger
- Department of Entomology and Plant Pathology, University of Arkansas Systems Division of Agriculture, Fayetteville, AR, USA
| | - C. Elizabeth Oakley
- Department of Molecular Biosciences, University of Kansas, Lawrence, KS, USA
| | - Berl R. Oakley
- Department of Molecular Biosciences, University of Kansas, Lawrence, KS, USA
| | - Martin J. Egan
- Department of Entomology and Plant Pathology, University of Arkansas Systems Division of Agriculture, Fayetteville, AR, USA
| | - Xin Xiang
- Department of Biochemistry and Molecular Biology, The Uniformed Services University of the Health Sciences- F. Edward Hébert School of Medicine, Bethesda, Maryland 20814, USA
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13
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King GA, Wettstein R, Varberg JM, Chetlapalli K, Walsh ME, Gillet LC, Hernández-Armenta C, Beltrao P, Aebersold R, Jaspersen SL, Matos J, Ünal E. Meiotic nuclear pore complex remodeling provides key insights into nuclear basket organization. J Cell Biol 2023; 222:e202204039. [PMID: 36515990 PMCID: PMC9754704 DOI: 10.1083/jcb.202204039] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 09/12/2022] [Accepted: 11/05/2022] [Indexed: 12/15/2022] Open
Abstract
Nuclear pore complexes (NPCs) are large proteinaceous assemblies that mediate nuclear compartmentalization. NPCs undergo large-scale structural rearrangements during mitosis in metazoans and some fungi. However, our understanding of NPC remodeling beyond mitosis remains limited. Using time-lapse fluorescence microscopy, we discovered that NPCs undergo two mechanistically separable remodeling events during budding yeast meiosis in which parts or all of the nuclear basket transiently dissociate from the NPC core during meiosis I and II, respectively. Meiosis I detachment, observed for Nup60 and Nup2, is driven by Polo kinase-mediated phosphorylation of Nup60 at its interface with the Y-complex. Subsequent reattachment of Nup60-Nup2 to the NPC core is facilitated by a lipid-binding amphipathic helix in Nup60. Preventing Nup60-Nup2 reattachment causes misorganization of the entire nuclear basket in gametes. Strikingly, meiotic nuclear basket remodeling also occurs in the distantly related fission yeast, Schizosaccharomyces pombe. Our study reveals a conserved and developmentally programmed aspect of NPC plasticity, providing key mechanistic insights into the nuclear basket organization.
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Affiliation(s)
- Grant A. King
- Department of Molecular and Cell Biology, University of California, Berkeley, CA
| | - Rahel Wettstein
- Institute of Biochemistry, ETH Zürich, Zürich, Switzerland
- Max Perutz Labs, University of Vienna, Vienna, Austria
| | | | | | - Madison E. Walsh
- Department of Molecular and Cell Biology, University of California, Berkeley, CA
| | - Ludovic C.J. Gillet
- Institute of Molecular Systems Biology, Department of Biology, ETH Zürich, Zürich, Switzerland
| | - Claudia Hernández-Armenta
- European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Wellcome Genome Campus, Cambridge, UK
| | - Pedro Beltrao
- Institute of Molecular Systems Biology, Department of Biology, ETH Zürich, Zürich, Switzerland
- European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Wellcome Genome Campus, Cambridge, UK
| | - Ruedi Aebersold
- Institute of Molecular Systems Biology, Department of Biology, ETH Zürich, Zürich, Switzerland
| | - Sue L. Jaspersen
- Stowers Institute for Medical Research, Kansas City, MO
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, KS
| | - Joao Matos
- Institute of Biochemistry, ETH Zürich, Zürich, Switzerland
- Max Perutz Labs, University of Vienna, Vienna, Austria
| | - Elçin Ünal
- Department of Molecular and Cell Biology, University of California, Berkeley, CA
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14
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Wang Z, Bartholomai BM, Loros JJ, Dunlap JC. Optimized fluorescent proteins for 4-color and photoconvertible live-cell imaging in Neurospora crassa. Fungal Genet Biol 2023; 164:103763. [PMID: 36481248 PMCID: PMC10501358 DOI: 10.1016/j.fgb.2022.103763] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 11/27/2022] [Accepted: 11/30/2022] [Indexed: 12/12/2022]
Abstract
Fungal cells are quite unique among life in their organization and structure, and yet implementation of many tools recently developed for fluorescence imaging in animal systems and yeast has been slow in filamentous fungi. Here we present analysis of properties of fluorescent proteins in Neurospora crassa as well as describing genetic tools for the expression of these proteins that may be useful beyond cell biology applications. The brightness and photostability of ten different fluorescent protein tags were compared in a well-controlled system; six different promoters are described for the assessment of the fluorescent proteins and varying levels of expression, as well as a customizable bidirectional promoter system. We present an array of fluorescent proteins suitable for use across the visible light spectrum to allow for 4-color imaging, in addition to a photoconvertible fluorescent protein that enables a change in the color of a small subset of proteins in the cell. These tools build on the rich history of cell biology research in filamentous fungi and provide new tools to help expand research capabilities.
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Affiliation(s)
- Ziyan Wang
- Geisel School of Medicine at Dartmouth, Department of Molecular and Systems Biology, Hanover, NH, USA
| | - Bradley M Bartholomai
- Geisel School of Medicine at Dartmouth, Department of Molecular and Systems Biology, Hanover, NH, USA
| | - Jennifer J Loros
- Geisel School of Medicine at Dartmouth, Department of Biochemistry and Cell Biology, Hanover, NH, USA
| | - Jay C Dunlap
- Geisel School of Medicine at Dartmouth, Department of Molecular and Systems Biology, Hanover, NH, USA.
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15
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Antonin W, Siniossoglou S. Nuclear Shape-Shifters: Lipid and Protein Dynamics at the Nuclear Envelope. Cells 2022; 11:cells11244120. [PMID: 36552884 PMCID: PMC9776944 DOI: 10.3390/cells11244120] [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: 12/06/2022] [Accepted: 12/12/2022] [Indexed: 12/24/2022] Open
Abstract
The nuclear envelope constitutes a selective barrier that segregates chromatin into the nucleus of eukaryotic cells [...].
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Affiliation(s)
- Wolfram Antonin
- Institute of Biochemistry and Molecular Cell Biology, Medical School, RWTH Aachen University, 52074 Aachen, Germany
- Correspondence: (W.A.); (S.S.)
| | - Symeon Siniossoglou
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, UK
- Correspondence: (W.A.); (S.S.)
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16
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James SW, Palmer J, Keller NP, Brown ML, Dunworth MR, Francisco SG, Watson KG, Titchen B, Achimovich A, Mahoney A, Artemiou JP, Buettner KG, Class M, Sydenstricker AL, Anglin SL. A reciprocal translocation involving Aspergillus nidulans snxAHrb1/Gbp2 and gyfA uncovers a new regulator of the G2-M transition and reveals a role in transcriptional repression for the setBSet2 histone H3-lysine-36 methyltransferase. Genetics 2022; 222:iyac130. [PMID: 36005881 PMCID: PMC9526064 DOI: 10.1093/genetics/iyac130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Accepted: 08/09/2022] [Indexed: 12/24/2022] Open
Abstract
Aspergillus nidulans snxA, an ortholog of Saccharomyces cerevisiae Hrb1/Gbp2 messenger RNA shuttle proteins, is-in contrast to budding yeast-involved in cell cycle regulation, in which snxA1 and snxA2 mutations as well as a snxA deletion specifically suppress the heat sensitivity of mutations in regulators of the CDK1 mitotic induction pathway. snxA mutations are strongly cold sensitive, and at permissive temperature snxA mRNA and protein expression are strongly repressed. Initial attempts to identify the causative snxA mutations revealed no defects in the SNXA protein. Here, we show that snxA1/A2 mutations resulted from an identical chromosome I-II reciprocal translocation with breakpoints in the snxA first intron and the fourth exon of a GYF-domain gene, gyfA. Surprisingly, a gyfA deletion and a reconstructed gyfA translocation allele suppressed the heat sensitivity of CDK1 pathway mutants in a snxA+ background, demonstrating that 2 unrelated genes, snxA and gyfA, act through the CDK1-CyclinB axis to restrain the G2-M transition, and for the first time identifying a role in G2-M regulation for a GYF-domain protein. To better understand snxA1/A2-reduced expression, we generated suppressors of snxA cold sensitivity in 2 genes: (1) loss of the abundant nucleolar protein Nsr1/nucleolin bypassed the requirement for snxA and (2) loss of the Set2 histone H3 lysine36 (H3K36) methyltransferase or a nonmethylatable histone H3K36L mutant rescued hypomorphic snxA mutants by restoring full transcriptional proficiency, indicating that methylation of H3K36 acts normally to repress snxA transcription. These observations are in line with known Set2 functions in preventing excessive and cryptic transcription of active genes.
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Affiliation(s)
- Steven W James
- Department of Biology, Gettysburg College, Gettysburg, PA 17325, USA
| | - Jonathan Palmer
- Data Analytics, Genencor Technology Center, IFF, Palo Alto, CA, 94306, USA
| | - Nancy P Keller
- Department of Medical Microbiology and Immunology, University of Wisconsin—Madison, Madison, WI 53726, USA
| | - Morgan L Brown
- Department of Cell and Developmental Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Matthew R Dunworth
- Department of Cell Biology, Johns Hopkins School of Medicine, Baltimore, MD 21218, USA
| | - Sarah G Francisco
- Department of Otolaryngology, Boston Children’s Hospital, Boston, MA 02115, USA
| | - Katherine G Watson
- School of Medicine, Noorda College of Osteopathic Medicine, Provo, UT 84606, USA
| | - Breanna Titchen
- Department of Biological and Biomedical Sciences, Harvard University, Cambridge, MA 02138, USA
| | - Alecia Achimovich
- Department of Chemistry, Gettysburg College, Gettysburg, PA 17325, USA
| | - Andrew Mahoney
- Department of Chemistry, Emory University, Atlanta, GA 30322, USA
| | | | - Kyra G Buettner
- School of Medicine, Thomas Jefferson University, Philadelphia, PA 19144, USA
| | - Madelyn Class
- School of Medicine, Temple University, Philadelphia, PA 19140, USA
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17
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Borah S, Dhanasekaran K, Kumar S. The LEM-ESCRT toolkit: Repair and maintenance of the nucleus. Front Cell Dev Biol 2022; 10:989217. [PMID: 36172278 PMCID: PMC9512039 DOI: 10.3389/fcell.2022.989217] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Accepted: 08/24/2022] [Indexed: 12/04/2022] Open
Abstract
The eukaryotic genome is enclosed in a nuclear envelope that protects it from potentially damaging cellular activities and physically segregates transcription and translation.Transport across the NE is highly regulated and occurs primarily via the macromolecular nuclear pore complexes.Loss of nuclear compartmentalization due to defects in NPC function and NE integrity are tied to neurological and ageing disorders like Alzheimer’s, viral pathogenesis, immune disorders, and cancer progression.Recent work implicates inner-nuclear membrane proteins of the conserved LEM domain family and the ESCRT machinery in NE reformation during cell division and NE repair upon rupture in migrating cancer cells, and generating seals over defective NPCs. In this review, we discuss the recent in-roads made into defining the molecular mechanisms and biochemical networks engaged by LEM and many other integral inner nuclear membrane proteins to preserve the nuclear barrier.
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Affiliation(s)
- Sapan Borah
- National Institute of Immunohaematology, Mumbai, Maharashtra, India
- *Correspondence: Sapan Borah, ; Karthigeyan Dhanasekaran, ; Santosh Kumar,
| | - Karthigeyan Dhanasekaran
- Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, Haryana, India
- *Correspondence: Sapan Borah, ; Karthigeyan Dhanasekaran, ; Santosh Kumar,
| | - Santosh Kumar
- National Centre for Cell Science, Pune, Maharashtra, India
- *Correspondence: Sapan Borah, ; Karthigeyan Dhanasekaran, ; Santosh Kumar,
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18
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Torisawa T, Kimura A. Sequential accumulation of dynein and its regulatory proteins at the spindle region in the Caenorhabditis elegans embryo. Sci Rep 2022; 12:11740. [PMID: 35817834 PMCID: PMC9273622 DOI: 10.1038/s41598-022-15042-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 06/16/2022] [Indexed: 11/09/2022] Open
Abstract
Cytoplasmic dynein is responsible for various cellular processes during the cell cycle. The mechanism by which its activity is regulated spatially and temporarily inside the cell remains elusive. There are various regulatory proteins of dynein, including dynactin, NDEL1/NUD-2, and LIS1. Characterizing the spatiotemporal localization of regulatory proteins in vivo will aid understanding of the cellular regulation of dynein. Here, we focused on spindle formation in the Caenorhabditis elegans early embryo, wherein dynein and its regulatory proteins translocated from the cytoplasm to the spindle region upon nuclear envelope breakdown (NEBD). We found that (i) a limited set of dynein regulatory proteins accumulated in the spindle region, (ii) the spatial localization patterns were distinct among the regulators, and (iii) the regulatory proteins did not accumulate in the spindle region simultaneously but sequentially. Furthermore, the accumulation of NUD-2 was unique among the regulators. NUD-2 started to accumulate before NEBD (pre-NEBD accumulation), and exhibited the highest enrichment compared to the cytoplasmic concentration. Using a protein injection approach, we revealed that the C-terminal helix of NUD-2 was responsible for pre-NEBD accumulation. These findings suggest a fine temporal control of the subcellular localization of regulatory proteins.
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Affiliation(s)
- Takayuki Torisawa
- Cell Architecture Laboratory, National Institute of Genetics, Mishima, Japan.,Department of Genetics, The Graduate University for Advanced Studies, Sokendai, Mishima, Japan
| | - Akatsuki Kimura
- Cell Architecture Laboratory, National Institute of Genetics, Mishima, Japan. .,Department of Genetics, The Graduate University for Advanced Studies, Sokendai, Mishima, Japan.
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19
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Varberg JM, Unruh JR, Bestul AJ, Khan AA, Jaspersen SL. Quantitative analysis of nuclear pore complex organization in Schizosaccharomyces pombe. Life Sci Alliance 2022; 5:e202201423. [PMID: 35354597 PMCID: PMC8967992 DOI: 10.26508/lsa.202201423] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 03/11/2022] [Accepted: 03/14/2022] [Indexed: 01/06/2023] Open
Abstract
The number, distribution, and composition of nuclear pore complexes (NPCs) in the nuclear envelope varies between cell types and changes during cellular differentiation and in disease. To understand how NPC density and organization are controlled, we analyzed the NPC number and distribution in the fission yeast Schizosaccharomyces pombe using structured illumination microscopy. The small size of yeast nuclei, genetic features of fungi, and our robust image analysis pipeline allowed us to study NPCs in intact nuclei under multiple conditions. Our data revealed that NPC density is maintained across a wide range of nuclear sizes. Regions of reduced NPC density are observed over the nucleolus and surrounding the spindle pole body (SPB). Lem2-mediated tethering of the centromeres to the SPB is required to maintain NPC exclusion near SPBs. These findings provide a quantitative understanding of NPC number and distribution in S. pombe and show that interactions between the centromere and the nuclear envelope influences local NPC distribution.
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Affiliation(s)
| | - Jay R Unruh
- Stowers Institute for Medical Research, Kansas City, MO, USA
| | - Andrew J Bestul
- Stowers Institute for Medical Research, Kansas City, MO, USA
| | - Azqa A Khan
- Stowers Institute for Medical Research, Kansas City, MO, USA
| | - Sue L Jaspersen
- Stowers Institute for Medical Research, Kansas City, MO, USA
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, KS, USA
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20
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Abstract
Aspergillus fumigatus is the primary mold pathogen in humans. It can cause a wide range of diseases in humans, with high mortality rates in immunocompromised patients. The first-line treatments for invasive A. fumigatus infections are the triazole antifungals that inhibit Cyp51 lanosterol demethylase activity, blocking ergosterol biosynthesis. However, triazole-resistant strains of A. fumigatus are increasingly encountered, leading to increased mortality. The most common triazole resistance mechanisms in A. fumigatus are alterations in the cyp51A gene or promoter. We tested the hypothesis that A. fumigatus can acquire triazole resistance by horizontal gene transfer (HGT) of resistance-conferring gene cyp51A. HGT has not been experimentally analyzed in filamentous fungi. Therefore, we developed an HGT assay containing donor A. fumigatus strains carrying resistance-conferring mutated cyp51A, either in its chromosomal locus or in a self-replicating plasmid, and recipient strains that were hygromycin resistant and triazole sensitive. Donor and recipient A. fumigatus strains were cocultured and transferred to selective conditions, and the recipient strain tested for transferred triazole resistance. We found that chromosomal transfer of triazole resistance required selection under both voriconazole and hygromycin, resulting in diploid formation. Notably, plasmid-mediated transfer was also activated by voriconazole or hypoxic stress alone, suggesting a possible route to HGT of antifungal resistance in A. fumigatus, both in the environment and during host infection. This study provides, for the first time, preliminary experimental evidence for HGT mediating antifungal resistance in a pathogenic fungus. IMPORTANCE It is well known that bacteria can transfer antibiotic resistance from one strain to another by horizontal gene transfer (HGT), leading to the current worldwide crisis of rapidly emerging antibiotic-resistant bacteria. However, in fungi, HGT events have only been indirectly documented by whole-genome sequencing. This study directly examined fungal HGT of antibiotic resistance in a laboratory setting. We show that HGT of antifungal triazole resistance occurs in the important human fungal pathogen Aspergillus fumigatus. Importantly, we show a plasmid-mediated transfer of triazole resistance occurs under conditions likely to prevail in the environment and in infected patients. This study provides an experimental foundation for future work identifying the drivers and mechanistic underpinnings of HGT in fungi.
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21
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Dultz E, Wojtynek M, Medalia O, Onischenko E. The Nuclear Pore Complex: Birth, Life, and Death of a Cellular Behemoth. Cells 2022; 11:1456. [PMID: 35563762 PMCID: PMC9100368 DOI: 10.3390/cells11091456] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 04/22/2022] [Accepted: 04/23/2022] [Indexed: 02/01/2023] Open
Abstract
Nuclear pore complexes (NPCs) are the only transport channels that cross the nuclear envelope. Constructed from ~500-1000 nucleoporin proteins each, they are among the largest macromolecular assemblies in eukaryotic cells. Thanks to advances in structural analysis approaches, the construction principles and architecture of the NPC have recently been revealed at submolecular resolution. Although the overall structure and inventory of nucleoporins are conserved, NPCs exhibit significant compositional and functional plasticity even within single cells and surprising variability in their assembly pathways. Once assembled, NPCs remain seemingly unexchangeable in post-mitotic cells. There are a number of as yet unresolved questions about how the versatility of NPC assembly and composition is established, how cells monitor the functional state of NPCs or how they could be renewed. Here, we review current progress in our understanding of the key aspects of NPC architecture and lifecycle.
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Affiliation(s)
- Elisa Dultz
- Institute of Biochemistry, Department of Biology, ETHZ Zurich, 8093 Zurich, Switzerland;
| | - Matthias Wojtynek
- Institute of Biochemistry, Department of Biology, ETHZ Zurich, 8093 Zurich, Switzerland;
- Department of Biochemistry, University of Zurich, 8057 Zurich, Switzerland;
| | - Ohad Medalia
- Department of Biochemistry, University of Zurich, 8057 Zurich, Switzerland;
| | - Evgeny Onischenko
- Department of Biological Sciences, University of Bergen, 5020 Bergen, Norway
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22
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Raices M, D'Angelo MA. Structure, Maintenance, and Regulation of Nuclear Pore Complexes: The Gatekeepers of the Eukaryotic Genome. Cold Spring Harb Perspect Biol 2022; 14:a040691. [PMID: 34312247 PMCID: PMC8789946 DOI: 10.1101/cshperspect.a040691] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
In eukaryotic cells, the genetic material is segregated inside the nucleus. This compartmentalization of the genome requires a transport system that allows cells to move molecules across the nuclear envelope, the membrane-based barrier that surrounds the chromosomes. Nuclear pore complexes (NPCs) are the central component of the nuclear transport machinery. These large protein channels penetrate the nuclear envelope, creating a passage between the nucleus and the cytoplasm through which nucleocytoplasmic molecule exchange occurs. NPCs are one of the largest protein assemblies of eukaryotic cells and, in addition to their critical function in nuclear transport, these structures also play key roles in many cellular processes in a transport-independent manner. Here we will review the current knowledge of the NPC structure, the cellular mechanisms that regulate their formation and maintenance, and we will provide a brief description of a variety of processes that NPCs regulate.
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Affiliation(s)
- Marcela Raices
- Cell and Molecular Biology of Cancer Program, NCI-Designated Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California 92037, USA
| | - Maximiliano A D'Angelo
- Cell and Molecular Biology of Cancer Program, NCI-Designated Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California 92037, USA
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23
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Akey CW, Singh D, Ouch C, Echeverria I, Nudelman I, Varberg JM, Yu Z, Fang F, Shi Y, Wang J, Salzberg D, Song K, Xu C, Gumbart JC, Suslov S, Unruh J, Jaspersen SL, Chait BT, Sali A, Fernandez-Martinez J, Ludtke SJ, Villa E, Rout MP. Comprehensive structure and functional adaptations of the yeast nuclear pore complex. Cell 2022; 185:361-378.e25. [PMID: 34982960 PMCID: PMC8928745 DOI: 10.1016/j.cell.2021.12.015] [Citation(s) in RCA: 111] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 11/26/2021] [Accepted: 12/13/2021] [Indexed: 02/06/2023]
Abstract
Nuclear pore complexes (NPCs) mediate the nucleocytoplasmic transport of macromolecules. Here we provide a structure of the isolated yeast NPC in which the inner ring is resolved by cryo-EM at sub-nanometer resolution to show how flexible connectors tie together different structural and functional layers. These connectors may be targets for phosphorylation and regulated disassembly in cells with an open mitosis. Moreover, some nucleoporin pairs and transport factors have similar interaction motifs, which suggests an evolutionary and mechanistic link between assembly and transport. We provide evidence for three major NPC variants that may foreshadow functional specializations at the nuclear periphery. Cryo-electron tomography extended these studies, providing a model of the in situ NPC with a radially expanded inner ring. Our comprehensive model reveals features of the nuclear basket and central transporter, suggests a role for the lumenal Pom152 ring in restricting dilation, and highlights structural plasticity that may be required for transport.
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Affiliation(s)
- Christopher W Akey
- Department of Physiology and Biophysics, Boston University School of Medicine, 700 Albany Street, Boston, MA 02118, USA.
| | - Digvijay Singh
- Section of Molecular Biology, Division of Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Christna Ouch
- Department of Physiology and Biophysics, Boston University School of Medicine, 700 Albany Street, Boston, MA 02118, USA; Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 364 Plantation Street, Worcester, MA 01605, USA
| | - Ignacia Echeverria
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA, USA; Department of Cellular and Molecular Pharmacology, San Francisco, San Francisco, CA 94158, USA
| | - Ilona Nudelman
- Laboratory of Cellular and Structural Biology, The Rockefeller University, New York, NY 10065, USA
| | | | - Zulin Yu
- Stowers Institute for Medical Research, Kansas City, MO, USA
| | - Fei Fang
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Yi Shi
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Junjie Wang
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, NY, USA
| | - Daniel Salzberg
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA, USA
| | - Kangkang Song
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 364 Plantation Street, Worcester, MA 01605, USA
| | - Chen Xu
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 364 Plantation Street, Worcester, MA 01605, USA
| | - James C Gumbart
- School of Physics, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Sergey Suslov
- Section of Molecular Biology, Division of Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Jay Unruh
- Stowers Institute for Medical Research, Kansas City, MO, USA
| | - Sue L Jaspersen
- Stowers Institute for Medical Research, Kansas City, MO, USA; Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, KS, USA
| | - Brian T Chait
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, NY, USA
| | - Andrej Sali
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA, USA; Quantitative Biosciences Institute, University of California San Francisco, San Francisco, CA 94158, USA; Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, CA 94158, USA
| | | | - Steven J Ludtke
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, 1 Baylor Plaza, Houston, Texas 77030, USA.
| | - Elizabeth Villa
- Section of Molecular Biology, Division of Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA; Howard Hughes Medical Institute, University of California, San Diego, La Jolla, CA 92093, USA.
| | - Michael P Rout
- Laboratory of Cellular and Structural Biology, The Rockefeller University, New York, NY 10065, USA.
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24
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Spindle Dynamics during Meiotic Development of the Fungus Podospora anserina Requires the Endoplasmic Reticulum-Shaping Protein RTN1. mBio 2021; 12:e0161521. [PMID: 34607459 PMCID: PMC8546617 DOI: 10.1128/mbio.01615-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The endoplasmic reticulum (ER) is an elaborate organelle composed of distinct structural and functional domains. ER structure and dynamics involve membrane-shaping proteins of the reticulon and Yop1/DP1 families, which promote membrane curvature and regulate ER shaping and remodeling. Here, we analyzed the function of the reticulon (RTN1) and Yop1 proteins (YOP1 and YOP2) of the model fungus Podospora anserina and their contribution to sexual development. We found that RTN1 and YOP2 localize to the peripheral ER and are enriched in the dynamic apical ER domains of the polarized growing hyphal region. We discovered that the formation of these domains is diminished in the absence of RTN1 or YOP2 and abolished in the absence of YOP1 and that hyphal growth is moderately reduced when YOP1 is deleted in combination with RTN1 and/or YOP2. In addition, we found that RTN1 associates with the Spitzenkörper. Moreover, RTN1 localization is regulated during meiotic development, where it accumulates at the apex of growing asci (meiocytes) during their differentiation and at their middle region during the subsequent meiotic progression. Furthermore, we discovered that loss of RTN1 affects ascospore (meiotic spore) formation, in a process that does not involve YOP1 or YOP2. Finally, we show that the defects in ascospore formation of rtn1 mutants are associated with defective nuclear segregation and spindle dynamics throughout meiotic development. Our results show that sexual development in P. anserina involves a developmental remodeling of the ER that implicates the reticulon RTN1, which is required for meiotic nucleus segregation.
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25
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Gräf R, Grafe M, Meyer I, Mitic K, Pitzen V. The Dictyostelium Centrosome. Cells 2021; 10:cells10102657. [PMID: 34685637 PMCID: PMC8534566 DOI: 10.3390/cells10102657] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 10/01/2021] [Accepted: 10/02/2021] [Indexed: 12/13/2022] Open
Abstract
The centrosome of Dictyostelium amoebae contains no centrioles and consists of a cylindrical layered core structure surrounded by a corona harboring microtubule-nucleating γ-tubulin complexes. It is the major centrosomal model beyond animals and yeasts. Proteomics, protein interaction studies by BioID and superresolution microscopy methods led to considerable progress in our understanding of the composition, structure and function of this centrosome type. We discuss all currently known components of the Dictyostelium centrosome in comparison to other centrosomes of animals and yeasts.
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Carrasco-Navarro U, Aguirre J. H 2O 2 Induces Major Phosphorylation Changes in Critical Regulators of Signal Transduction, Gene Expression, Metabolism and Developmental Networks in Aspergillus nidulans. J Fungi (Basel) 2021; 7:624. [PMID: 34436163 PMCID: PMC8399174 DOI: 10.3390/jof7080624] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 07/27/2021] [Accepted: 07/28/2021] [Indexed: 12/13/2022] Open
Abstract
Reactive oxygen species (ROS) regulate several aspects of cell physiology in filamentous fungi including the antioxidant response and development. However, little is known about the signaling pathways involved in these processes. Here, we report Aspergillus nidulans global phosphoproteome during mycelial growth and show that under these conditions, H2O2 induces major changes in protein phosphorylation. Among the 1964 phosphoproteins we identified, H2O2 induced the phosphorylation of 131 proteins at one or more sites as well as the dephosphorylation of a larger set of proteins. A detailed analysis of these phosphoproteins shows that H2O2 affected the phosphorylation of critical regulatory nodes of phosphoinositide, MAPK, and TOR signaling as well as the phosphorylation of multiple proteins involved in the regulation of gene expression, primary and secondary metabolism, and development. Our results provide a novel and extensive protein phosphorylation landscape in A. nidulans, indicating that H2O2 induces a shift in general metabolism from anabolic to catabolic, and the activation of multiple stress survival pathways. Our results expand the significance of H2O2 in eukaryotic cell signaling.
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Affiliation(s)
| | - Jesús Aguirre
- Departamento de Biología Celular y del Desarrollo, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Apartado Postal 70-242, Ciudad de México 04510, Mexico;
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Kutay U, Jühlen R, Antonin W. Mitotic disassembly and reassembly of nuclear pore complexes. Trends Cell Biol 2021; 31:1019-1033. [PMID: 34294532 DOI: 10.1016/j.tcb.2021.06.011] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 06/28/2021] [Accepted: 06/28/2021] [Indexed: 12/19/2022]
Abstract
Nuclear pore complexes (NPCs) are huge protein assemblies within the nuclear envelope (NE) that serve as selective gates for macromolecular transport between nucleus and cytoplasm. When higher eukaryotic cells prepare for division, they rapidly disintegrate NPCs during NE breakdown such that nuclear and cytoplasmic components mix to enable the formation of a cytoplasmic mitotic spindle. At the end of mitosis, reassembly of NPCs is coordinated with the establishment of the NE around decondensing chromatin. We review recent progress on mitotic NPC disassembly and reassembly, focusing on vertebrate cells. We highlight novel mechanistic insights into how NPCs are rapidly disintegrated into conveniently reusable building blocks, and put divergent models of (post-)mitotic NPC assembly into a spatial and temporal context.
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Affiliation(s)
- Ulrike Kutay
- Institute of Biochemistry, Department of Biology, Eidgenössische Technische Hochschule (ETH) Zurich, Otto-Stern-Weg 3, 8093 Zurich, Switzerland.
| | - Ramona Jühlen
- Institute of Biochemistry and Molecular Cell Biology, Medical School, Rheinisch-Westfälische Technische Hochschule (RWTH) Aachen University, Pauwelsstrasse 30, 52074 Aachen, Germany
| | - Wolfram Antonin
- Institute of Biochemistry and Molecular Cell Biology, Medical School, Rheinisch-Westfälische Technische Hochschule (RWTH) Aachen University, Pauwelsstrasse 30, 52074 Aachen, Germany.
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28
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Bestul AJ, Yu Z, Unruh JR, Jaspersen SL. Redistribution of centrosomal proteins by centromeres and Polo kinase controls partial nuclear envelope breakdown in fission yeast. Mol Biol Cell 2021; 32:1487-1500. [PMID: 34133218 PMCID: PMC8351742 DOI: 10.1091/mbc.e21-05-0239] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Proper mitotic progression in Schizosaccharomyces pombe requires partial nuclear envelope breakdown (NEBD) and insertion of the spindle pole body (SPB—yeast centrosome) to build the mitotic spindle. Linkage of the centromere to the SPB is vital to this process, but why that linkage is important is not well understood. Utilizing high-resolution structured illumination microscopy, we show that the conserved Sad1-UNC-84 homology-domain protein Sad1 and other SPB proteins redistribute during mitosis to form a ring complex around SPBs, which is a precursor for localized NEBD and spindle formation. Although the Polo kinase Plo1 is not necessary for Sad1 redistribution, it localizes to the SPB region connected to the centromere, and its activity is vital for redistribution of other SPB ring proteins and for complete NEBD at the SPB to allow for SPB insertion. Our results lead to a model in which centromere linkage to the SPB drives redistribution of Sad1 and Plo1 activation that in turn facilitate partial NEBD and spindle formation through building of a SPB ring structure.
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Affiliation(s)
- Andrew J Bestul
- Stowers Institute for Medical Research, Kansas City, MO 64110
| | - Zulin Yu
- Stowers Institute for Medical Research, Kansas City, MO 64110
| | - Jay R Unruh
- Stowers Institute for Medical Research, Kansas City, MO 64110
| | - Sue L Jaspersen
- Stowers Institute for Medical Research, Kansas City, MO 64110.,Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, KS 66160
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29
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Ikui AE, Ueki N, Pecani K, Cross FR. Control of pre-replicative complex during the division cycle in Chlamydomonas reinhardtii. PLoS Genet 2021; 17:e1009471. [PMID: 33909603 PMCID: PMC8081180 DOI: 10.1371/journal.pgen.1009471] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 03/07/2021] [Indexed: 12/31/2022] Open
Abstract
DNA replication is fundamental to all living organisms. In yeast and animals, it is triggered by an assembly of pre-replicative complex including ORC, CDC6 and MCMs. Cyclin Dependent Kinase (CDK) regulates both assembly and firing of the pre-replicative complex. We tested temperature-sensitive mutants blocking Chlamydomonas DNA replication. The mutants were partially or completely defective in DNA replication and did not produce mitotic spindles. After a long G1, wild type Chlamydomonas cells enter a division phase when it undergoes multiple rapid synchronous divisions ('multiple fission'). Using tagged transgenic strains, we found that MCM4 and MCM6 were localized to the nucleus throughout the entire multiple fission division cycle, except for transient cytoplasmic localization during each mitosis. Chlamydomonas CDC6 was transiently localized in nucleus in early division cycles. CDC6 protein levels were very low, probably due to proteasomal degradation. CDC6 levels were severely reduced by inactivation of CDKA1 (CDK1 ortholog) but not the plant-specific CDKB1. Proteasome inhibition did not detectably increase CDC6 levels in the cdka1 mutant, suggesting that CDKA1 might upregulate CDC6 at the transcriptional level. All of the DNA replication proteins tested were essentially undetectable until late G1. They accumulated specifically during multiple fission and then were degraded as cells completed their terminal divisions. We speculate that loading of origins with the MCM helicase may not occur until the end of the long G1, unlike in the budding yeast system. We also developed a simple assay for salt-resistant chromatin binding of MCM4, and found that tight MCM4 loading was dependent on ORC1, CDC6 and MCM6, but not on RNR1 or CDKB1. These results provide a microbial framework for approaching replication control in the plant kingdom.
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Affiliation(s)
- Amy E. Ikui
- Department of Biology, Brooklyn College, The City University of New York, New York City, New York, United States of America
- * E-mail: (AEI); (FRC)
| | - Noriko Ueki
- Department of Biology, Brooklyn College, The City University of New York, New York City, New York, United States of America
| | - Kresti Pecani
- Laboratory of Cell Cycle Genetics, The Rockefeller University, New York City, New York, United States of America
| | - Frederick R. Cross
- Laboratory of Cell Cycle Genetics, The Rockefeller University, New York City, New York, United States of America
- * E-mail: (AEI); (FRC)
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30
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Bieger BD, Osmani AH, Xiang X, Egan MJ. The spindle pole-body localization of activated cytoplasmic dynein is cell cycle-dependent in Aspergillus nidulans. Fungal Genet Biol 2021; 148:103519. [PMID: 33472115 DOI: 10.1016/j.fgb.2021.103519] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 12/28/2020] [Accepted: 12/29/2020] [Indexed: 11/16/2022]
Abstract
Cytoplasmic dynein is a minus end-directed microtubule motor that can be activated by cargo adapters. In Aspergillus nidulans, overexpression of ΔC-HookA, the early endosomal adapter HookA missing its cargo-binding site, causes activated dynein to accumulate at septa and spindle pole bodies (SPBs) where the microtubule-organizing centers are located. Intriguingly, only some interphase nuclei show SPB signals of dynein. Here we present data demonstrating that localization of the activated dynein at SPBs is cell cycle-dependent: SPB dynein signals are seen to associate with nuclei at early G1 but disappear at about the G1-S boundary.
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Affiliation(s)
- Baronger Dowell Bieger
- Department of Entomology and Plant Pathology, University of Arkansas Systems Division of Agriculture, Fayetteville, AR, USA
| | - Aysha H Osmani
- Department of Molecular Genetics, The Ohio State University, Columbus, OH, USA
| | - Xin Xiang
- Department of Biochemistry and Molecular Biology, the Uniformed Services University - F. Edward Hébert School of Medicine, Bethesda, MD, USA.
| | - Martin J Egan
- Department of Entomology and Plant Pathology, University of Arkansas Systems Division of Agriculture, Fayetteville, AR, USA.
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31
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Dey G, Baum B. Nuclear envelope remodelling during mitosis. Curr Opin Cell Biol 2021; 70:67-74. [PMID: 33421755 PMCID: PMC8129912 DOI: 10.1016/j.ceb.2020.12.004] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 12/07/2020] [Accepted: 12/09/2020] [Indexed: 12/20/2022]
Abstract
The defining feature of the eukaryotic cell, the nucleus, is bounded by a double envelope. This envelope and the nuclear pores within it play a critical role in separating the genome from the cytoplasm. It also presents cells with a challenge. How are cells to remodel the nuclear compartment boundary during mitosis without compromising nuclear function? In the two billion years since the emergence of the first cells with a nucleus, eukaryotes have evolved a range of strategies to do this. At one extreme, the nucleus is disassembled upon entry into mitosis and then reassembled anew in the two daughter cells. At the other, cells maintain an intact nuclear compartment boundary throughout the division process. In this review, we discuss common features of the division process that underpin remodelling mechanisms, the topological challenges involved and speculate on the selective pressures that may drive the evolution of distinct modes of division.
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Affiliation(s)
- Gautam Dey
- Cell Biology and Biophysics, European Molecular Biology Laboratory, 69117, Heidelberg, Germany.
| | - Buzz Baum
- Lab of Molecular Biology, Cambridge, CB2 0QH, United Kingdom; Lab for Molecular Cell Biology, UCL, London, WC1E 6BT, United Kingdom.
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32
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Dissecting the Structural Dynamics of the Nuclear Pore Complex. Mol Cell 2020; 81:153-165.e7. [PMID: 33333016 DOI: 10.1016/j.molcel.2020.11.032] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2020] [Revised: 10/02/2020] [Accepted: 11/18/2020] [Indexed: 01/03/2023]
Abstract
Cellular processes are largely carried out by macromolecular assemblies, most of which are dynamic, having components that are in constant flux. One such assembly is the nuclear pore complex (NPC), an ∼50 MDa assembly comprised of ∼30 different proteins called Nups that mediates selective macromolecular transport between the nucleus and cytoplasm. We developed a proteomics method to provide a comprehensive picture of the yeast NPC component dynamics. We discovered that, although all Nups display uniformly slow turnover, their exchange rates vary considerably. Surprisingly, this exchange rate was relatively unrelated to each Nup's position, accessibility, or role in transport but correlated with its structural role; scaffold-forming Nups exchange slowly, whereas flexible connector Nups threading throughout the NPC architecture exchange more rapidly. Targeted perturbations in the NPC structure revealed a dynamic resilience to damage. Our approach opens a new window into macromolecular assembly dynamics.
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33
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Pfeifer MA, Khang CH. Nup84 persists within the nuclear envelope of the rice blast fungus, Magnaporthe oryzae, during mitosis. Fungal Genet Biol 2020; 146:103472. [PMID: 32980454 DOI: 10.1016/j.fgb.2020.103472] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 09/17/2020] [Accepted: 09/18/2020] [Indexed: 02/09/2023]
Abstract
The arrangement of the nuclear envelope in the rice blast fungus, Magnaporthe oryzae, was previously undetermined. Here, we identified two conserved components of the nuclear envelope, a core nucleoporin, Nup84, and an inner nuclear membrane protein, Src1. Live-cell super-resolution structured illumination microscopy revealed that Nup84-tdTomato and Src1-EGFP colocalized within the nuclear envelope during interphase and that Nup84-tdTomato remained associated with the dividing nucleus. We also found that appressorium development involved a mitotic nuclear migration event through the germ tube.
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Affiliation(s)
- Mariel A Pfeifer
- Department of Plant Biology, 2502 Miller Plant Sciences, University of Georgia, Athens, GA 30602-7271, USA
| | - Chang Hyun Khang
- Department of Plant Biology, 2502 Miller Plant Sciences, University of Georgia, Athens, GA 30602-7271, USA.
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34
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Hülle Cells of Aspergillus nidulans with Nuclear Storage and Developmental Backup Functions Are Reminiscent of Multipotent Stem Cells. mBio 2020; 11:mBio.01673-20. [PMID: 32788382 PMCID: PMC7439468 DOI: 10.1128/mbio.01673-20] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Some aspergilli are among the most cosmopolitan and ecologically dominant fungal species. One pillar of their success is their complex life cycle, which creates specialized cell types for versatile dispersal and regenesis. One of these cell types is unique to aspergilli-the Hülle cells. Despite being known for over a century, the biological and ecological roles of Hülle cells remain largely speculative. Previously reported data on in vivo Hülle cell formation and localization have been conflicting. Our quantification reveals that Hülle cells can occur at all locations on hyphae and that they show cellular activity similar to that seen with adjacent hyphae, indicating that they develop as intricate parts of hyphal tissue. In addition, we show that during sexual development associated with two parental strains, the typically multinucleate Hülle cells can inherit nuclei from both parents, indicating that they may serve as genetic backups. We provide an easy, reproducible method to study Hülle cell biology and germination with which we investigate the 90-year-old puzzle of whether and how Hülle cells germinate. We present clear evidence for the germination of Hülle cells, and we show that Hülle cells grow hyphae that develop into a spore-producing colony. Finally, we show that Hülle cell-derived colonies produce conidiospores faster than spore-derived colonies, providing evidence for an as-yet-undescribed developmental shortcut program in Aspergillus nidulans We propose that Hülle cells represent a unique cell type as specialized hypha-derived sexual tissue with a nucleus storage function and may act as fungal backup stem cells under highly destructive conditions.IMPORTANCE The in vivo identification of Hülle cells in cases of aspergillosis infections in animals and humans illustrates their biological relevance and suggests that they might be involved in pathogenicity. It is striking that aspergilli have developed and maintained a multinucleate nurse cell that is presumably energy-intensive to produce and is usually found only in higher eukaryotes. Our findings shed light on how the understudied Hülle cells might contribute to the success of aspergilli by acting not only as nurse cells under detrimental conditions (sexual development) but also as fungal backup stem cells with the capacity to produce genetically diverse spores in an accelerated manner, thereby substantially contributing to survival in response to predator attack or under otherwise severely destructive conditions. Our study solved the 90-year-old puzzle of Hülle cell germination and provides easy, reproducible methods that will facilitate future studies on biological and ecological roles of Hülle cells in aspergilli.
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35
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Yasui M, Oda K, Masuo S, Hosoda S, Katayama T, Maruyama JI, Takaya N, Takeshita N. Invasive growth of Aspergillus oryzae in rice koji and increase of nuclear number. Fungal Biol Biotechnol 2020; 7:8. [PMID: 32518660 PMCID: PMC7275602 DOI: 10.1186/s40694-020-00099-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 05/23/2020] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND 'Rice koji' is a solid culture of Aspergillus oryzae on steamed rice grains. Multiple parallel fermentation, wherein saccharification of rice by A. oryzae and alcohol fermentation by the budding yeast occur simultaneously, leads to the formation of a variety of ingredients of Japanese sake. In sake brewing, the degree of mycelial invasive growth into the steamed rice, called 'haze-komi', highly correlates with the digestibility and quality of rice koji, since the hyphae growing into the rice secrete amylases and digest starch. RESULTS In this study, we investigated mycelial distribution of GFP-tagged A. oryzae in rice koji made with different types of rice, such as sake rice and eating rice, with 50 or 90% polishing rate to remove abundant proteins and lipids near the surface. In addition, we compared transcriptomes of A. oryzae in the different types of rice koji. Finally, we found that A. oryzae increases the nuclear number and hyphal width in the course of 1-3 days cultivation. CONCLUSIONS Our imaging analyses indicate that A. oryzae hyphae grew more deeply into 50% polished rice than 90% polished rice. The increases of nuclear number may be a selectively acquired characteristic for the high secretory capacity during the long history of cultivation of this species.
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Affiliation(s)
- Mizuki Yasui
- Microbiology Research Center for Sustainability (MiCS), Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
| | - Ken Oda
- National Research Institute of Brewing, 3-7-1 Kagamiyama, Higashi-hiroshima, Hiroshima, 739-0046 Japan
| | - Shunsuke Masuo
- Microbiology Research Center for Sustainability (MiCS), Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
| | - Shuji Hosoda
- Microbiology Research Center for Sustainability (MiCS), Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
| | - Takuya Katayama
- Department of Biotechnology, Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, Tokyo, Japan
| | - Jun-ichi Maruyama
- Department of Biotechnology, Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, Tokyo, Japan
| | - Naoki Takaya
- Microbiology Research Center for Sustainability (MiCS), Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
| | - Norio Takeshita
- Microbiology Research Center for Sustainability (MiCS), Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
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36
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King GA, Ünal E. The dynamic nuclear periphery as a facilitator of gamete health and rejuvenation. Curr Genet 2020; 66:487-493. [PMID: 31915924 PMCID: PMC7202962 DOI: 10.1007/s00294-019-01050-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 12/20/2019] [Accepted: 12/21/2019] [Indexed: 12/26/2022]
Abstract
The nuclear periphery is a hotspot for the accumulation of age-induced damage in eukaryotic cells. The types of damage that occur at the periphery and their phenotypic consequences have begun to be characterized; however, the mechanisms by which cells repair or eliminate nuclear damage remain poorly understood. Using budding yeast meiosis as a natural system to study cellular rejuvenation, we recently discovered a novel nuclear quality control event, in which age-induced damage is sequestered away from dividing chromosomes to a discarded nuclear compartment that we term the GUNC (for "Gametogenesis Uninherited Nuclear Compartment"). Interestingly, extensive nuclear remodeling occurs even in young cells, including a surprising modularity of the nuclear pore complex, suggesting a general contribution to gamete fitness. In this review, we discuss these findings in the context of recent evidence that the nuclear periphery is a highly dynamic region critical for cellular health.
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Affiliation(s)
- Grant A King
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, 94720, USA
| | - Elçin Ünal
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, 94720, USA.
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Otamendi A, Perez-de-Nanclares-Arregi E, Oiartzabal-Arano E, Cortese MS, Espeso EA, Etxebeste O. Developmental regulators FlbE/D orchestrate the polarity site-to-nucleus dynamics of the fungal bZIP transcription factor FlbB. Cell Mol Life Sci 2019; 76:4369-4390. [PMID: 31065746 PMCID: PMC11105705 DOI: 10.1007/s00018-019-03121-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2018] [Revised: 04/17/2019] [Accepted: 04/29/2019] [Indexed: 12/19/2022]
Abstract
Permanently polarized cells have developed transduction mechanisms linking polarity sites with gene regulation in the nucleus. In neurons, one mechanism is based on long-distance retrograde migration of transcription factors (TFs). Aspergillus nidulans FlbB is the only known fungal TF shown to migrate retrogradely to nuclei from the polarized region of fungal cells known as hyphae. There, FlbB controls developmental transitions by triggering the production of asexual multicellular structures. FlbB dynamics in hyphae is orchestrated by regulators FlbE and FlbD. At least three FlbE domains are involved in the acropetal transport of FlbB, with a final MyoE/actin filament-dependent step from the subapex to the apex. Experiments employing a T2A viral peptide-containing chimera (FlbE::mRFP::T2A::FlbB::GFP) suggest that apical FlbB/FlbE interaction is inhibited to initiate a dynein-dependent FlbB transport to nuclei. FlbD controls the nuclear accumulation of FlbB through a cMyb domain and a C-terminal LxxLL motif. Overall, results elucidate a highly dynamic pattern of FlbB interactions, which enable timely developmental induction. Furthermore, this system establishes a reference for TF-based long-distance signaling in permanently polarized cells.
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Affiliation(s)
- Ainara Otamendi
- Biochemistry II Laboratory, Department of Applied Chemistry, Faculty of Chemistry, University of The Basque Country, Manuel de Lardizabal, 3, 20018, San Sebastian, Spain
| | - Elixabet Perez-de-Nanclares-Arregi
- Biochemistry II Laboratory, Department of Applied Chemistry, Faculty of Chemistry, University of The Basque Country, Manuel de Lardizabal, 3, 20018, San Sebastian, Spain
| | - Elixabet Oiartzabal-Arano
- Biochemistry II Laboratory, Department of Applied Chemistry, Faculty of Chemistry, University of The Basque Country, Manuel de Lardizabal, 3, 20018, San Sebastian, Spain
| | - Marc S Cortese
- Biochemistry II Laboratory, Department of Applied Chemistry, Faculty of Chemistry, University of The Basque Country, Manuel de Lardizabal, 3, 20018, San Sebastian, Spain
| | - Eduardo A Espeso
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas (CSIC), Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Oier Etxebeste
- Biochemistry II Laboratory, Department of Applied Chemistry, Faculty of Chemistry, University of The Basque Country, Manuel de Lardizabal, 3, 20018, San Sebastian, Spain.
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38
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Identification of the guanine nucleotide exchange factor for SAR1 in the filamentous fungal model Aspergillus nidulans. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2019; 1866:118551. [PMID: 31487505 DOI: 10.1016/j.bbamcr.2019.118551] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 08/02/2019] [Accepted: 08/11/2019] [Indexed: 12/30/2022]
Abstract
In spite of its basic and applied interest, the regulation of ER exit by filamentous fungi is insufficiently understood. In previous work we isolated a panel of conditional mutations in sarA encoding the master GTPase SarASAR1 in A. nidulans and demonstrated its key role in exocytosis and hyphal morphogenesis. However, the SAR1 guanine nucleotide exchange factor (GEF), Sec12, has not been characterized in any filamentous fungus, largely due to the fact that SEC12 homologues share little amino acid sequence identity beyond a GGGGxxxxGϕxN motif involved in guanine nucleotide exchange. Here we demonstrate that AN11127 encodes A. nidulans Sec12, which is an essential protein that localizes to the ER and that, when overexpressed, rescues the growth defect resulting from a hypomorphic sarA6ts mutation at 37 °C. Using purified, bacterially expressed proteins we demonstrate that the product of AN11127 accelerates nucleotide exchange on SarASAR1, but not on its closely related GTPase ArfAARF1, as expected for a bona fide GEF. The unequivocal characterization of A. nidulans Sec12 paves the way for the tailored modification of ER exit in a model organism that is closely related to industrial species of filamentous fungi.
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39
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Chemudupati M, Johns M, Osmani SA. The mode of mitosis is dramatically modified by deletion of a single nuclear pore complex gene in Aspergillus nidulans. Fungal Genet Biol 2019; 130:72-81. [PMID: 31026588 DOI: 10.1016/j.fgb.2019.04.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 04/18/2019] [Accepted: 04/19/2019] [Indexed: 02/06/2023]
Abstract
Nuclear pore complex (NPC) proteins (Nups) play multiple roles during mitosis. In this study we expand these roles and reveal that in Aspergillus nidulans, compromising the core Nup84-120 subcomplex of the NPC modifies the mitotic behavior of the nuclear envelope (NE). In wildtype cells, the NE undergoes simultaneous double pinching events to separate daughter nuclei during mitotic exit, whereas in Nup84-120 complex mutants, only one restriction of the NE is observed. Investigating the basis for this modified behavior of the NE in Nup deleted cells uncovered previously unrealized roles for core Nups in mitotic exit. During wildtype anaphase, the NE surrounds the two separating daughter DNA masses which typically flank the central nucleolus, to form three distinct nuclear compartments. In contrast, deletion of core Nups frequently results in early nucleolar eviction from the mitotic nucleus, in turn causing an uncharacteristic dumbbell-shaped NE morphology of anaphase nuclei with a nuclear membrane bridge connecting the two forming G1 nuclei. Importantly, the absence of the nucleolus between the separating daughter nuclei during anaphase delays chromosome segregation and progression into G1 as nuclei remain connected by chromatin bridges. Proteins localizing to late segregating chromosome arms are observed between forming daughter nuclei, and the mitotic spindle fails to resolve in a timely manner. These chromatin bridges are occupied by the Aurora kinase until nuclei have fully separated, suggesting involvement of Aurora in monitoring mitotic spindle and nuclear membrane resolution during mitotic exit. Our findings thus reveal a novel requirement for core Nups in mediating nucleolar positioning during mitosis, which dictates the pattern of NE fissions during karyokinesis and facilitates normal chromosome segregation. The findings additionally demonstrate that the mode of mitosis can be dramatically modified by deletion of a single NPC gene and reveals surprising fluidity in mitotic mechanisms.
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Affiliation(s)
- Mahesh Chemudupati
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210, United States; Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, United States
| | - Matthew Johns
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210, United States
| | - Stephen A Osmani
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210, United States; Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, United States.
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40
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Horio T, Szewczyk E, Oakley CE, Osmani AH, Osmani SA, Oakley BR. SUMOlock reveals a more complete Aspergillus nidulans SUMOylome. Fungal Genet Biol 2019; 127:50-59. [PMID: 30849444 DOI: 10.1016/j.fgb.2019.03.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 03/04/2019] [Accepted: 03/04/2019] [Indexed: 12/20/2022]
Abstract
SUMOylation, covalent attachment of the small ubiquitin-like modifier protein SUMO to proteins, regulates protein interactions and activity and plays a crucial role in the regulation of many key cellular processes. Understanding the roles of SUMO in these processes ultimately requires identification of the proteins that are SUMOylated in the organism under study. The filamentous fungus Aspergillus nidulans serves as an excellent model for many aspects of fungal biology, and it would be of great value to determine the proteins that are SUMOylated in this organism (i.e. its SUMOylome). We have developed a new and effective approach for identifying SUMOylated proteins in this organism in which we lock proteins in their SUMOylated state, affinity purify SUMOylated proteins using the high affinity S-tag, and identify them using sensitive Orbitrap mass spectroscopy. This approach allows us to distinguish proteins that are SUMOylated from proteins that are binding partners of SUMOylated proteins or are bound non-covalently to SUMO. This approach has allowed us to identify 149 proteins that are SUMOylated in A. nidulans. Of these, 67 are predicted to be involved in transcription and particularly in the regulation of transcription, 21 are predicted to be involved in RNA processing and 16 are predicted to function in DNA replication or repair.
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Affiliation(s)
- Tetsuya Horio
- Department of Natural Sciences, Nippon Sport Science University, 1221-1 Kamoshida-cho, Aoba-ku, Yokohama, Kanagawa 227-0033, Japan.
| | - Edyta Szewczyk
- Department of Molecular Genetics, The Ohio State University, 484 W. 12(th) Ave., Columbus, OH 43210, USA
| | - C Elizabeth Oakley
- Department of Molecular Biosciences, The University of Kansas, 1200 Sunnyside Ave., Lawrence, KS 66045, USA
| | - Aysha H Osmani
- Department of Molecular Genetics, The Ohio State University, 484 W. 12(th) Ave., Columbus, OH 43210, USA
| | - Stephen A Osmani
- Department of Molecular Genetics, The Ohio State University, 484 W. 12(th) Ave., Columbus, OH 43210, USA
| | - Berl R Oakley
- Department of Molecular Biosciences, The University of Kansas, 1200 Sunnyside Ave., Lawrence, KS 66045, USA
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41
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Suresh S, Osmani SA. Poring over chromosomes: mitotic nuclear pore complex segregation. Curr Opin Cell Biol 2019; 58:42-49. [PMID: 30798206 DOI: 10.1016/j.ceb.2019.01.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 01/09/2019] [Accepted: 01/18/2019] [Indexed: 01/23/2023]
Abstract
Eukaryotic cells rely on flux of macromolecules between the nucleus and the cytoplasm for growth and survival. Bidirectional transport is achieved through Nuclear Pore Complexes (NPCs) embedded in the Nuclear Envelope (NE). NPC proteins perform other cellular functions during mitosis, chromatin organization, DNA repair and gene regulation. Dysregulation of NPC number, or defects in their structure and function, are linked to numerous diseases but how NPCs are faithfully inherited during mitosis is poorly understood. In this review, we discuss recent insights to mechanisms of mammalian mitotic NPC segregation and NPC assembly as well as mitotic NPC inheritance via the mitotic chromatin located NPC protein Nup2 in Aspergillus nidulans. We suggest mitotic Nup2 chromatin-based mechanisms could also operate in vertebrate cells.
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Affiliation(s)
- Subbulakshmi Suresh
- Department of Molecular Genetics, The Ohio State University, 484 West 12th Avenue, Columbus, OH 43210, USA.
| | - Stephen A Osmani
- Department of Molecular Genetics, The Ohio State University, 484 West 12th Avenue, Columbus, OH 43210, USA
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42
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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: 11] [Impact Index Per Article: 1.6] [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.
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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
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43
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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: 3.4] [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.
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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.
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44
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Teimer R, Kosinski J, von Appen A, Beck M, Hurt E. A short linear motif in scaffold Nup145C connects Y-complex with pre-assembled outer ring Nup82 complex. Nat Commun 2017; 8:1107. [PMID: 29062044 PMCID: PMC5653651 DOI: 10.1038/s41467-017-01160-9] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 08/22/2017] [Indexed: 02/05/2023] Open
Abstract
Nucleocytoplasmic transport occurs through nuclear pore complexes (NPCs), which are formed from multiple copies of ~30 different nucleoporins (Nups) and inserted into the double nuclear membrane. Many of these Nups are organized into subcomplexes, of which the Y-shaped Nup84 complex is the major constituent of the nuclear and cytoplasmic rings. The Nup82–Nup159–Nsp1 complex is another module that, however, is only assembled into the cytoplasmic ring. By means of crosslinking mass spectrometry, biochemical reconstitution, and molecular modeling, we identified a short linear motif in the unstructured N-terminal region of Chaetomium thermophilum Nup145C, a subunit of the Y-complex, that is sufficient to recruit the Nup82 complex, but only in its assembled state. This finding points to a more general mechanism that short linear motifs in structural Nups can act as sensors to cooperatively connect pre-assembled NPC modules, thereby facilitating the formation and regulation of the higher-order NPC assembly. The Nup82–Nup159–Nsp1 complex, which plays a key role in mRNA export, is recruited late during the process of nuclear pore complex (NPC) assembly. Here the authors combine crosslinking mass spectrometry, biochemical reconstitution and molecular modeling to gain insights into the mechanism of Nup82 recruitment to the NPC.
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Affiliation(s)
- Roman Teimer
- Biochemistry Center of Heidelberg University (BZH), Im Neuenheimer Feld 328, 69120, Heidelberg, Germany
| | - Jan Kosinski
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstraße 1, 69117, Heidelberg, Germany
| | - Alexander von Appen
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstraße 1, 69117, Heidelberg, Germany
| | - Martin Beck
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstraße 1, 69117, Heidelberg, Germany.
| | - Ed Hurt
- Biochemistry Center of Heidelberg University (BZH), Im Neuenheimer Feld 328, 69120, Heidelberg, Germany.
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45
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Suresh S, Markossian S, Osmani AH, Osmani SA. Mitotic nuclear pore complex segregation involves Nup2 in Aspergillus nidulans. J Cell Biol 2017; 216:2813-2826. [PMID: 28747316 PMCID: PMC5584150 DOI: 10.1083/jcb.201610019] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 05/11/2017] [Accepted: 07/06/2017] [Indexed: 01/20/2023] Open
Abstract
Transport through nuclear pore complexes (NPCs) during interphase is facilitated by the nucleoporin Nup2 via its importin α- and Ran-binding domains. However, Aspergillus nidulans and vertebrate Nup2 also locate to chromatin during mitosis, suggestive of mitotic functions. In this study, we report that Nup2 is required for mitotic NPC inheritance in A. nidulans Interestingly, the role of Nup2 during mitotic NPC segregation is independent of its importin α- and Ran-binding domains but relies on a central targeting domain that is necessary for localization and viability. To test whether mitotic chromatin-associated Nup2 might function to bridge NPCs with chromatin during segregation, we provided an artificial link between NPCs and chromatin via Nup133 and histone H1. Using this approach, we bypassed the requirement of Nup2 for NPC segregation. This indicates that A. nidulans cells ensure accurate mitotic NPC segregation to daughter nuclei by linking mitotic DNA and NPC segregation via the mitotic specific chromatin association of Nup2.
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Affiliation(s)
- Subbulakshmi Suresh
- Department of Molecular Genetics, The Ohio State University, Columbus, OH
- Laboratory of Chemistry and Cell Biology, The Rockefeller University, New York, NY
| | - Sarine Markossian
- Department of Molecular Genetics, The Ohio State University, Columbus, OH
| | - Aysha H Osmani
- Department of Molecular Genetics, The Ohio State University, Columbus, OH
| | - Stephen A Osmani
- Department of Molecular Genetics, The Ohio State University, Columbus, OH
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Abstract
All cells must accurately replicate DNA and partition it to daughter cells. The basic cell cycle machinery is highly conserved among eukaryotes. Most of the mechanisms that control the cell cycle were worked out in fungal cells, taking advantage of their powerful genetics and rapid duplication times. Here we describe the cell cycles of the unicellular budding yeast Saccharomyces cerevisiae and the multicellular filamentous fungus Aspergillus nidulans. We compare and contrast morphological landmarks of G1, S, G2, and M phases, molecular mechanisms that drive cell cycle progression, and checkpoints in these model unicellular and multicellular fungal systems.
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47
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De Souza CP, Hashmi SB, Hage N, Fitch RM, Osmani AH, Osmani SA. Location and functional analysis of the Aspergillus nidulans Aurora kinase confirm mitotic functions and suggest non-mitotic roles. Fungal Genet Biol 2017; 103:1-15. [PMID: 28315405 PMCID: PMC11443558 DOI: 10.1016/j.fgb.2017.03.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Accepted: 03/12/2017] [Indexed: 11/17/2022]
Abstract
Filamentous fungi have devastating negative impacts as pathogens and agents of food spoilage but also have critical ecological importance and are utilized for industrial applications. The characteristic multinucleate nature of filamentous fungi is facilitated by limiting if, when and where septation, the fungal equivalent of cytokinesis, occurs. In the model filamentous fungus Aspergillus nidulans septation does not occur immediately after mitosis and is an incomplete process resulting in the formation of a septal pore whose permeability is cell cycle regulated. How mitotic regulators, such as the Aurora kinase, contribute to the often unique biology of filamentous fungi is not well understood. The Aurora B kinase has not previously been investigated in any detail during hyphal growth. Here we demonstrate for the first time that Aurora displays cell cycle dependent locations to the region of forming septa, the septal pore and mature septa as well as the mitotic apparatus. To functionally analyze Aurora, we generated a temperature sensitive allele revealing essential mitotic and spindle assembly checkpoint functions consistent with its location to the kinetochore region and spindle midzone. Our analysis also reveals that cellular and kinetochore Aurora levels increase during a mitotic spindle assembly checkpoint arrest and we propose that this could be important for checkpoint inactivation when spindle formation is prevented. We demonstrate that Aurora accumulation at mature septa following mitotic entry does not require mitotic progression but is dependent upon a timing mechanism. Surprisingly we also find that Aurora inactivation leads to cellular swelling and lysis indicating an unexpected function for Aurora in fungal cell growth. Thus in addition to its conserved mitotic functions our data suggest that Aurora has the capacity to be an important regulator of septal biology and cell growth in filamentous fungi.
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Affiliation(s)
- Colin P De Souza
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210, United States
| | - Shahr B Hashmi
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210, United States
| | - Natalie Hage
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210, United States
| | - Rebecca M Fitch
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210, United States
| | - Aysha H Osmani
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210, United States
| | - Stephen A Osmani
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210, United States.
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Kikuma T, Mitani T, Kohara T, Maruyama JI, Kitamoto K. Carbon and nitrogen depletion-induced nucleophagy and selective autophagic sequestration of a whole nucleus in multinucleate cells of the filamentous fungus Aspergillus oryzae. J GEN APPL MICROBIOL 2017; 63:139-146. [PMID: 28331162 DOI: 10.2323/jgam.2016.09.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Autophagy is a conserved cellular degradation process in eukaryotes, in which cytoplasmic components and organelles are digested in vacuoles/lysosomes. Recently, autophagic degradation of nuclear materials, termed "nucleophagy", has been reported. In the multinucleate filamentous fungus Aspergillus oryzae, a whole nucleus is degraded by nucleophagy after prolonged culture. While developing an H2B-EGFP processing assay for the evaluation of nucleophagy in A. oryzae, we found that nucleophagy is efficiently induced by carbon or nitrogen depletion. Microscopic observations in a carbon depletion condition clearly demonstrated that autophagosomes selectively sequester a particular nucleus, despite the presence of multiple nuclei in the same cell. Furthermore, AoNsp1, the A. oryzae homolog of the yeast nucleoporin Nsp1p, mainly localized at the nuclear periphery, but its localization was restricted to the opposite side of the autophagosome being formed around a nucleus. In contrast, the perinuclear ER visualized with the calnexin AoClxA was not morphologically affected by nucleophagy. The findings of nucleophagy-inducing conditions enabled us to characterize the morphological process of autophagic degradation of a whole nucleus in multinucleate cells.
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49
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Pantazopoulou A. The Golgi apparatus: insights from filamentous fungi. Mycologia 2017; 108:603-22. [DOI: 10.3852/15-309] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 01/01/2016] [Indexed: 02/06/2023]
Affiliation(s)
- Areti Pantazopoulou
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, Madrid 28040, Spain
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50
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Meyer I, Peter T, Batsios P, Kuhnert O, Krüger-Genge A, Camurça C, Gräf R. CP39, CP75 and CP91 are major structural components of the Dictyostelium centrosome's core structure. Eur J Cell Biol 2017; 96:119-130. [PMID: 28104305 DOI: 10.1016/j.ejcb.2017.01.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Revised: 12/13/2016] [Accepted: 01/09/2017] [Indexed: 12/11/2022] Open
Abstract
The acentriolar Dictyostelium centrosome is a nucleus-associated body consisting of a core structure with three plaque-like layers, which are surrounded by a microtubule-nucleating corona. The core duplicates once per cell cycle at the G2/M transition, whereby its central layer disappears and the two outer layers form the mitotic spindle poles. Through proteomic analysis of isolated centrosomes, we have identified CP39 and CP75, two essential components of the core structure. Both proteins can be assigned to the central core layer as their centrosomal presence is correlated to the disappearance and reappearance of the central core layer in the course of centrosome duplication. Both proteins contain domains with centrosome-binding activity in their N- and C-terminal halves, whereby the respective N-terminal half is required for cell cycle-dependent regulation. CP39 is capable of self-interaction and GFP-CP39 overexpression elicited supernumerary microtubule-organizing centers and pre-centrosomal cytosolic clusters. Underexpression stopped cell growth and reversed the MTOC amplification phenotype. In contrast, in case of CP75 underexpression of the protein by RNAi treatment elicited supernumerary MTOCs. In addition, CP75RNAi affects correct chromosome segregation and causes co-depletion of CP39 and CP91, another central core layer component. CP39 and CP75 interact with each other directly in a yeast two-hybrid assay. Furthermore, CP39, CP75 and CP91 mutually interact in a proximity-dependent biotin identification (BioID) assay. Our data indicate that these three proteins are all required for proper centrosome biogenesis and make up the major structural components of core structure's central layer.
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Affiliation(s)
- Irene Meyer
- University of Potsdam, Institute for Biochemistry and Biology, Dept. of Cell Biology, Karl-Liebknecht-Straße 24-25, Haus 26, D-14476 Potsdam-Golm, Germany.
| | - Tatjana Peter
- University of Potsdam, Institute for Biochemistry and Biology, Dept. of Cell Biology, Karl-Liebknecht-Straße 24-25, Haus 26, D-14476 Potsdam-Golm, Germany
| | - Petros Batsios
- University of Potsdam, Institute for Biochemistry and Biology, Dept. of Cell Biology, Karl-Liebknecht-Straße 24-25, Haus 26, D-14476 Potsdam-Golm, Germany
| | - Oliver Kuhnert
- University of Potsdam, Institute for Biochemistry and Biology, Dept. of Cell Biology, Karl-Liebknecht-Straße 24-25, Haus 26, D-14476 Potsdam-Golm, Germany
| | - Anne Krüger-Genge
- University of Potsdam, Institute for Biochemistry and Biology, Dept. of Cell Biology, Karl-Liebknecht-Straße 24-25, Haus 26, D-14476 Potsdam-Golm, Germany
| | - Carl Camurça
- University of Potsdam, Institute for Biochemistry and Biology, Dept. of Cell Biology, Karl-Liebknecht-Straße 24-25, Haus 26, D-14476 Potsdam-Golm, Germany
| | - Ralph Gräf
- University of Potsdam, Institute for Biochemistry and Biology, Dept. of Cell Biology, Karl-Liebknecht-Straße 24-25, Haus 26, D-14476 Potsdam-Golm, Germany.
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