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Bakshi A, Iturra FE, Alamban A, Rosas-Salvans M, Dumont S, Aydogan MG. Cytoplasmic division cycles without the nucleus and mitotic CDK/cyclin complexes. Cell 2023; 186:4694-4709.e16. [PMID: 37832525 PMCID: PMC10659773 DOI: 10.1016/j.cell.2023.09.010] [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: 06/05/2022] [Revised: 05/11/2023] [Accepted: 09/12/2023] [Indexed: 10/15/2023]
Abstract
Cytoplasmic divisions are thought to rely on nuclear divisions and mitotic signals. We demonstrate in Drosophila embryos that cytoplasm can divide repeatedly without nuclei and mitotic CDK/cyclin complexes. Cdk1 normally slows an otherwise faster cytoplasmic division cycle, coupling it with nuclear divisions, and when uncoupled, cytoplasm starts dividing before mitosis. In developing embryos where CDK/cyclin activity can license mitotic microtubule (MT) organizers like the spindle, cytoplasmic divisions can occur without the centrosome, a principal organizer of interphase MTs. However, centrosomes become essential in the absence of CDK/cyclin activity, implying that the cytoplasm can employ either the centrosome-based interphase or CDK/cyclin-dependent mitotic MTs to facilitate its divisions. Finally, we present evidence that autonomous cytoplasmic divisions occur during unperturbed fly embryogenesis and that they may help extrude mitotically stalled nuclei during blastoderm formation. We postulate that cytoplasmic divisions occur in cycles governed by a yet-to-be-uncovered clock mechanism autonomous from CDK/cyclin complexes.
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Affiliation(s)
- Anand Bakshi
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Fabio Echegaray Iturra
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Andrew Alamban
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA; Biophysics Graduate Program, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Miquel Rosas-Salvans
- Department of Bioengineering and Therapeutic Science, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Sophie Dumont
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA; Chan Zuckerberg Biohub, San Francisco, CA 94158, USA
| | - Mustafa G Aydogan
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA; Biophysics Graduate Program, University of California, San Francisco, San Francisco, CA 94158, USA.
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2
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Zhao A, Varady S, O'Kelley-Bangsberg M, Deng V, Platenkamp A, Wijngaard P, Bern M, Gormley W, Kushkowski E, Thompson K, Tibbetts L, Conner AT, Noeckel D, Teran A, Ritz A, Applewhite DA. From network analysis to experimental validation: identification of regulators of non-muscle myosin II contractility using the folded-gastrulation signaling pathway. BMC Mol Cell Biol 2023; 24:32. [PMID: 37821823 PMCID: PMC10568788 DOI: 10.1186/s12860-023-00492-3] [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: 07/04/2023] [Accepted: 09/29/2023] [Indexed: 10/13/2023] Open
Abstract
The morphogenetic process of apical constriction, which relies on non-muscle myosin II (NMII) generated constriction of apical domains of epithelial cells, is key to the development of complex cellular patterns. Apical constriction occurs in almost all multicellular organisms, but one of the most well-characterized systems is the Folded-gastrulation (Fog)-induced apical constriction that occurs in Drosophila. The binding of Fog to its cognizant receptors Mist/Smog results in a signaling cascade that leads to the activation of NMII-generated contractility. Despite our knowledge of key molecular players involved in Fog signaling, we sought to explore whether other proteins have an undiscovered role in its regulation. We developed a computational method to predict unidentified candidate NMII regulators using a network of pairwise protein-protein interactions called an interactome. We first constructed a Drosophila interactome of over 500,000 protein-protein interactions from several databases that curate high-throughput experiments. Next, we implemented several graph-based algorithms that predicted 14 proteins potentially involved in Fog signaling. To test these candidates, we used RNAi depletion in combination with a cellular contractility assay in Drosophila S2R + cells, which respond to Fog by contracting in a stereotypical manner. Of the candidates we screened using this assay, two proteins, the serine/threonine phosphatase Flapwing and the putative guanylate kinase CG11811 were demonstrated to inhibit cellular contractility when depleted, suggestive of their roles as novel regulators of the Fog pathway.
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Affiliation(s)
- Andy Zhao
- Reed College Department of Biology, 3203 SE Woodstock Blvd, Portland, OR, 97202, USA
| | - Sophia Varady
- Reed College Department of Biology, 3203 SE Woodstock Blvd, Portland, OR, 97202, USA
| | | | - Vicki Deng
- Reed College Department of Biology, 3203 SE Woodstock Blvd, Portland, OR, 97202, USA
| | - Amy Platenkamp
- Reed College Department of Biology, 3203 SE Woodstock Blvd, Portland, OR, 97202, USA
| | - Petra Wijngaard
- Reed College Department of Biology, 3203 SE Woodstock Blvd, Portland, OR, 97202, USA
| | - Miriam Bern
- Reed College Department of Biology, 3203 SE Woodstock Blvd, Portland, OR, 97202, USA
| | - Wyatt Gormley
- Reed College Department of Biology, 3203 SE Woodstock Blvd, Portland, OR, 97202, USA
| | - Elaine Kushkowski
- Reed College Department of Biology, 3203 SE Woodstock Blvd, Portland, OR, 97202, USA
| | - Kat Thompson
- Reed College Department of Biology, 3203 SE Woodstock Blvd, Portland, OR, 97202, USA
| | - Logan Tibbetts
- Reed College Department of Biology, 3203 SE Woodstock Blvd, Portland, OR, 97202, USA
| | - A Tamar Conner
- Reed College Department of Biology, 3203 SE Woodstock Blvd, Portland, OR, 97202, USA
| | - David Noeckel
- Reed College Department of Biology, 3203 SE Woodstock Blvd, Portland, OR, 97202, USA
| | - Aidan Teran
- Reed College Department of Biology, 3203 SE Woodstock Blvd, Portland, OR, 97202, USA
| | - Anna Ritz
- Reed College Department of Biology, 3203 SE Woodstock Blvd, Portland, OR, 97202, USA.
| | - Derek A Applewhite
- Reed College Department of Biology, 3203 SE Woodstock Blvd, Portland, OR, 97202, USA.
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3
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Zhu Z, Becam I, Tovey CA, Elfarkouchi A, Yen EC, Bernard F, Guichet A, Conduit PT. Multifaceted modes of γ-tubulin complex recruitment and microtubule nucleation at mitotic centrosomes. J Cell Biol 2023; 222:e202212043. [PMID: 37698931 PMCID: PMC10497398 DOI: 10.1083/jcb.202212043] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 05/18/2023] [Accepted: 07/24/2023] [Indexed: 09/14/2023] Open
Abstract
Microtubule nucleation is mediated by γ-tubulin ring complexes (γ-TuRCs). In most eukaryotes, a GCP4/5/4/6 "core" complex promotes γ-tubulin small complex (γ-TuSC) association to generate cytosolic γ-TuRCs. Unlike γ-TuSCs, however, this core complex is non-essential in various species and absent from budding yeasts. In Drosophila, Spindle defective-2 (Spd-2) and Centrosomin (Cnn) redundantly recruit γ-tubulin complexes to mitotic centrosomes. Here, we show that Spd-2 recruits γ-TuRCs formed via the GCP4/5/4/6 core, but Cnn can recruit γ-TuSCs directly via its well-conserved CM1 domain, similar to its homologs in budding yeast. When centrosomes fail to recruit γ-tubulin complexes, they still nucleate microtubules via the TOG domain protein Mini-spindles (Msps), but these microtubules have different dynamic properties. Our data, therefore, help explain the dispensability of the GCP4/5/4/6 core and highlight the robustness of centrosomes as microtubule organizing centers. They also suggest that the dynamic properties of microtubules are influenced by how they are nucleated.
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Affiliation(s)
- Zihan Zhu
- Department of Zoology, University of Cambridge, Cambridge, UK
| | - Isabelle Becam
- Université Paris Cité, CNRS, Institut Jacques Monod, Paris, France
| | - Corinne A. Tovey
- Université Paris Cité, CNRS, Institut Jacques Monod, Paris, France
| | - Abir Elfarkouchi
- Université Paris Cité, CNRS, Institut Jacques Monod, Paris, France
| | - Eugenie C. Yen
- Department of Zoology, University of Cambridge, Cambridge, UK
| | - Fred Bernard
- Université Paris Cité, CNRS, Institut Jacques Monod, Paris, France
| | - Antoine Guichet
- Université Paris Cité, CNRS, Institut Jacques Monod, Paris, France
| | - Paul T. Conduit
- Department of Zoology, University of Cambridge, Cambridge, UK
- Université Paris Cité, CNRS, Institut Jacques Monod, Paris, France
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4
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Galletta BJ, Varadarajan R, Fagerstrom CJ, Yang B, Haase KP, McJunkin K, Rusan NM. The E3 ligase Poe promotes Pericentrin degradation. Mol Biol Cell 2023; 34:br15. [PMID: 37342879 PMCID: PMC10398894 DOI: 10.1091/mbc.e22-11-0534] [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: 11/29/2022] [Revised: 06/07/2023] [Accepted: 06/13/2023] [Indexed: 06/23/2023] Open
Abstract
Centrosomes are essential parts of diverse cellular processes, and precise regulation of the levels of their constituent proteins is critical for their function. One such protein is Pericentrin (PCNT) in humans and Pericentrin-like protein (PLP) in Drosophila. Increased PCNT expression and its protein accumulation are linked to clinical conditions including cancer, mental disorders, and ciliopathies. However, the mechanisms by which PCNT levels are regulated remain underexplored. Our previous study demonstrated that PLP levels are sharply down-regulated during early spermatogenesis and this regulation is essential to spatially position PLP on the proximal end of centrioles. We hypothesized that the sharp drop in PLP protein was a result of rapid protein degradation during the male germ line premeiotic G2 phase. Here, we show that PLP is subject to ubiquitin-mediated degradation and identify multiple proteins that promote the reduction of PLP levels in spermatocytes, including the UBR box containing E3 ligase Poe (UBR4), which we show binds to PLP. Although protein sequences governing posttranslational regulation of PLP are not restricted to a single region of the protein, we identify a region that is required for Poe-mediated degradation. Experimentally stabilizing PLP, via internal PLP deletions or loss of Poe, leads to PLP accumulation in spermatocytes, its mispositioning along centrioles, and defects in centriole docking in spermatids.
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Affiliation(s)
- Brian J. Galletta
- Cell and Developmental Biology Center, National Heart, Lung, and Blood Institute, and
| | - Ramya Varadarajan
- Cell and Developmental Biology Center, National Heart, Lung, and Blood Institute, and
| | - Carey J. Fagerstrom
- Cell and Developmental Biology Center, National Heart, Lung, and Blood Institute, and
| | - Bing Yang
- Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Karen Plevock Haase
- Cell and Developmental Biology Center, National Heart, Lung, and Blood Institute, and
| | - Katherine McJunkin
- Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Nasser M. Rusan
- Cell and Developmental Biology Center, National Heart, Lung, and Blood Institute, and
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5
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Ali A, Vineethakumari C, Lacasa C, Lüders J. Microtubule nucleation and γTuRC centrosome localization in interphase cells require ch-TOG. Nat Commun 2023; 14:289. [PMID: 36702836 PMCID: PMC9879976 DOI: 10.1038/s41467-023-35955-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2021] [Accepted: 01/10/2023] [Indexed: 01/27/2023] Open
Abstract
Organization of microtubule arrays requires spatio-temporal regulation of the microtubule nucleator γ-tubulin ring complex (γTuRC) at microtubule organizing centers (MTOCs). MTOC-localized adapter proteins are thought to recruit and activate γTuRC, but the molecular underpinnings remain obscure. Here we show that at interphase centrosomes, rather than adapters, the microtubule polymerase ch-TOG (also named chTOG or CKAP5) ultimately controls γTuRC recruitment and activation. ch-TOG co-assembles with γTuRC to stimulate nucleation around centrioles. In the absence of ch-TOG, γTuRC fails to localize to these sites, but not the centriole lumen. However, whereas some ch-TOG is stably bound at subdistal appendages, it only transiently associates with PCM. ch-TOG's dynamic behavior requires its tubulin-binding TOG domains and a C-terminal region involved in localization. In addition, ch-TOG also promotes nucleation from the Golgi. Thus, at interphase centrosomes stimulation of nucleation and γTuRC attachment are mechanistically coupled through transient recruitment of ch-TOG, and ch-TOG's nucleation-promoting activity is not restricted to centrosomes.
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Affiliation(s)
- Aamir Ali
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, 08028, Spain
| | - Chithran Vineethakumari
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, 08028, Spain
| | - Cristina Lacasa
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, 08028, Spain
| | - Jens Lüders
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, 08028, Spain.
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6
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Shaw NM, Rios-Monterrosa JL, Fedorchak GR, Ketterer MR, Coombs GS, Lammerding J, Wallrath LL. Effects of mutant lamins on nucleo-cytoskeletal coupling in Drosophila models of LMNA muscular dystrophy. Front Cell Dev Biol 2022; 10:934586. [PMID: 36120560 PMCID: PMC9471154 DOI: 10.3389/fcell.2022.934586] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 07/20/2022] [Indexed: 11/13/2022] Open
Abstract
The nuclei of multinucleated skeletal muscles experience substantial external force during development and muscle contraction. Protection from such forces is partly provided by lamins, intermediate filaments that form a scaffold lining the inner nuclear membrane. Lamins play a myriad of roles, including maintenance of nuclear shape and stability, mediation of nuclear mechanoresponses, and nucleo-cytoskeletal coupling. Herein, we investigate how disease-causing mutant lamins alter myonuclear properties in response to mechanical force. This was accomplished via a novel application of a micropipette harpooning assay applied to larval body wall muscles of Drosophila models of lamin-associated muscular dystrophy. The assay enables the measurement of both nuclear deformability and intracellular force transmission between the cytoskeleton and nuclear interior in intact muscle fibers. Our studies revealed that specific mutant lamins increase nuclear deformability while other mutant lamins cause nucleo-cytoskeletal coupling defects, which were associated with loss of microtubular nuclear caging. We found that microtubule caging of the nucleus depended on Msp300, a KASH domain protein that is a component of the linker of nucleoskeleton and cytoskeleton (LINC) complex. Taken together, these findings identified residues in lamins required for connecting the nucleus to the cytoskeleton and suggest that not all muscle disease-causing mutant lamins produce similar defects in subcellular mechanics.
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Affiliation(s)
- Nicholas M. Shaw
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA, United States
| | - Jose L. Rios-Monterrosa
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA, United States
| | - Gregory R. Fedorchak
- The Nancy E. and Peter C. Meinig School of Biomedical Engineering, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY, United States
| | - Margaret R. Ketterer
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA, United States
| | - Gary S. Coombs
- Biology Department, Waldorf University, Forest City, IA, United States
| | - Jan Lammerding
- The Nancy E. and Peter C. Meinig School of Biomedical Engineering, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY, United States
| | - Lori L. Wallrath
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA, United States
- *Correspondence: Lori L. Wallrath,
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7
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Hannaford MR, Liu R, Billington N, Swider ZT, Galletta BJ, Fagerstrom CJ, Combs C, Sellers JR, Rusan NM. Pericentrin interacts with Kinesin-1 to drive centriole motility. J Biophys Biochem Cytol 2022; 221:213380. [PMID: 35929834 PMCID: PMC9361567 DOI: 10.1083/jcb.202112097] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Revised: 06/02/2022] [Accepted: 07/12/2022] [Indexed: 12/23/2022] Open
Abstract
Centrosome positioning is essential for their function. Typically, centrosomes are transported to various cellular locations through the interaction of centrosomal microtubules (MTs) with motor proteins anchored at the cortex or the nuclear surface. However, it remains unknown how centrioles migrate in cellular contexts in which they do not nucleate MTs. Here, we demonstrate that during interphase, inactive centrioles move directly along the interphase MT network as Kinesin-1 cargo. We identify Pericentrin-Like-Protein (PLP) as a novel Kinesin-1 interacting molecule essential for centriole motility. In vitro assays show that PLP directly interacts with the cargo binding domain of Kinesin-1, allowing PLP to migrate on MTs. Binding assays using purified proteins revealed that relief of Kinesin-1 autoinhibition is critical for its interaction with PLP. Finally, our studies of neural stem cell asymmetric divisions in the Drosophila brain show that the PLP-Kinesin-1 interaction is essential for the timely separation of centrioles, the asymmetry of centrosome activity, and the age-dependent centrosome inheritance.
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Affiliation(s)
- Matthew R. Hannaford
- Cell and Developmental Biology Center, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD
| | - Rong Liu
- Cell and Developmental Biology Center, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD
| | - Neil Billington
- Cell and Developmental Biology Center, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD
| | - Zachary T. Swider
- Cell and Developmental Biology Center, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD
| | - Brian J. Galletta
- Cell and Developmental Biology Center, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD
| | - Carey J. Fagerstrom
- Cell and Developmental Biology Center, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD
| | - Christian Combs
- Cell and Developmental Biology Center, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD
| | - James R. Sellers
- Cell and Developmental Biology Center, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD
| | - Nasser M. Rusan
- Cell and Developmental Biology Center, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD,Correspondence to Nasser M. Rusan:
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8
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Akhmanova A, Kapitein LC. Mechanisms of microtubule organization in differentiated animal cells. Nat Rev Mol Cell Biol 2022; 23:541-558. [PMID: 35383336 DOI: 10.1038/s41580-022-00473-y] [Citation(s) in RCA: 57] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/07/2022] [Indexed: 02/08/2023]
Abstract
Microtubules are polarized cytoskeletal filaments that serve as tracks for intracellular transport and form a scaffold that positions organelles and other cellular components and modulates cell shape and mechanics. In animal cells, the geometry, density and directionality of microtubule networks are major determinants of cellular architecture, polarity and proliferation. In dividing cells, microtubules form bipolar spindles that pull chromosomes apart, whereas in interphase cells, microtubules are organized in a cell type-specific fashion, which strongly correlates with cell physiology. In motile cells, such as fibroblasts and immune cells, microtubules are organized as radial asters, whereas in immotile epithelial and neuronal cells and in muscles, microtubules form parallel or antiparallel arrays and cortical meshworks. Here, we review recent work addressing how the formation of such microtubule networks is driven by the plethora of microtubule regulatory proteins. These include proteins that nucleate or anchor microtubule ends at different cellular structures and those that sever or move microtubules, as well as regulators of microtubule elongation, stability, bundling or modifications. The emerging picture, although still very incomplete, shows a remarkable diversity of cell-specific mechanisms that employ conserved building blocks to adjust microtubule organization in order to facilitate different cellular functions.
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Affiliation(s)
- Anna Akhmanova
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, Utrecht, the Netherlands.
| | - Lukas C Kapitein
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, Utrecht, the Netherlands.
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9
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Zhao AJ, Montes-Laing J, Perry WMG, Shiratori M, Merfeld E, Rogers SL, Applewhite DA. The Drosophila spectraplakin Short stop regulates focal adhesion dynamics by crosslinking microtubules and actin. Mol Biol Cell 2022; 33:ar19. [PMID: 35235367 PMCID: PMC9282009 DOI: 10.1091/mbc.e21-09-0434] [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] [Indexed: 11/11/2022] Open
Abstract
The spectraplakin family of proteins includes ACF7/MACF1 and BPAG1/dystonin in mammals, VAB-10 in Caenorhabditis elegans, Magellan in zebrafish, and Short stop (Shot), the sole Drosophila member. Spectraplakins are giant cytoskeletal proteins that cross-link actin, microtubules, and intermediate filaments, coordinating the activity of the entire cytoskeleton. We examined the role of Shot during cell migration using two systems: the in vitro migration of Drosophila tissue culture cells and in vivo through border cell migration. RNA interference (RNAi) depletion of Shot increases the rate of random cell migration in Drosophila tissue culture cells as well as the rate of wound closure during scratch-wound assays. This increase in cell migration prompted us to analyze focal adhesion dynamics. We found that the rates of focal adhesion assembly and disassembly were faster in Shot-depleted cells, leading to faster adhesion turnover that could underlie the increased migration speeds. This regulation of focal adhesion dynamics may be dependent on Shot being in an open confirmation. Using Drosophila border cells as an in vivo model for cell migration, we found that RNAi depletion led to precocious border cell migration. Collectively, these results suggest that spectraplakins not only function to cross-link the cytoskeleton but may regulate cell–matrix adhesion.
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Affiliation(s)
- Andrew J Zhao
- Department of Biology, Reed College, 3203 SE Woodstock Boulevard, Portland, OR 97202, USA
| | - Julia Montes-Laing
- Department of Biology, Reed College, 3203 SE Woodstock Boulevard, Portland, OR 97202, USA
| | - Wick M G Perry
- Department of Biology, Reed College, 3203 SE Woodstock Boulevard, Portland, OR 97202, USA
| | - Mari Shiratori
- Department of Biology, Reed College, 3203 SE Woodstock Boulevard, Portland, OR 97202, USA
| | - Emily Merfeld
- Department of Biology, Reed College, 3203 SE Woodstock Boulevard, Portland, OR 97202, USA
| | - Stephen L Rogers
- Department of Biology & Carolina Center for Genome Sciences, The University of North Carolina at Chapel Hill, Campus Box 3280, 422 Fordham Hall, Chapel Hill, NC 27599-3280, USA
| | - Derek A Applewhite
- Department of Biology, Reed College, 3203 SE Woodstock Boulevard, Portland, OR 97202, USA
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10
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Tsuchiya K, Goshima G. Microtubule-associated proteins promote microtubule generation in the absence of γ-tubulin in human colon cancer cells. J Cell Biol 2021; 220:e202104114. [PMID: 34779859 PMCID: PMC8598081 DOI: 10.1083/jcb.202104114] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 08/13/2021] [Accepted: 09/20/2021] [Indexed: 11/29/2022] Open
Abstract
The γ-tubulin complex acts as the predominant microtubule (MT) nucleator that initiates MT formation and is therefore an essential factor for cell proliferation. Nonetheless, cellular MTs are formed after experimental depletion of the γ-tubulin complex, suggesting that cells possess other factors that drive MT nucleation. Here, by combining gene knockout, auxin-inducible degron, RNA interference, MT depolymerization/regrowth assay, and live microscopy, we identified four microtubule-associated proteins (MAPs), ch-TOG, CLASP1, CAMSAPs, and TPX2, which are involved in γ-tubulin-independent MT generation in human colon cancer cells. In the mitotic MT regrowth assay, nucleated MTs organized noncentriolar MT organizing centers (ncMTOCs) in the absence of γ-tubulin. Depletion of CLASP1 or TPX2 substantially delayed ncMTOC formation, suggesting that these proteins might promote MT nucleation in the absence of γ-tubulin. In contrast, depletion of ch-TOG or CAMSAPs did not affect the timing of ncMTOC appearance. CLASP1 also accelerates γ-tubulin-independent MT regrowth during interphase. Thus, MT generation can be promoted by MAPs without the γ-tubulin template.
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Affiliation(s)
- Kenta Tsuchiya
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Japan
| | - Gohta Goshima
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Japan
- Sugashima Marine Biological Laboratory, Graduate School of Science, Nagoya University, Nagoya, Japan
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11
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Collins MA, Coon LA, Thomas R, Mandigo TR, Wynn E, Folker ES. Ensconsin-dependent changes in microtubule organization and LINC complex-dependent changes in nucleus-nucleus interactions result in quantitatively distinct myonuclear positioning defects. Mol Biol Cell 2021; 32:ar27. [PMID: 34524872 PMCID: PMC8693964 DOI: 10.1091/mbc.e21-06-0324] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Nuclear movement is a fundamental process of eukaryotic cell biology. Skeletal muscle presents an intriguing model to study nuclear movement because its development requires the precise positioning of multiple nuclei within a single cytoplasm. Furthermore, there is a high correlation between aberrant nuclear positioning and poor muscle function. Although many genes that regulate nuclear movement have been identified, the mechanisms by which these genes act are not known. Using Drosophila melanogaster muscle development as a model system and a combination of live-embryo microscopy and laser ablation of nuclei, we have found that clustered nuclei encompass at least two phenotypes that are caused by distinct mechanisms. Specifically, Ensconsin is necessary for productive force production to drive any movement of nuclei, whereas Bocksbeutel and Klarsicht are necessary to form distinct populations of nuclei that move to different cellular locations. Mechanistically, Ensconsin regulates the number of growing microtubules that are used to move nuclei, whereas Bocksbeutel and Klarsicht regulate interactions between nuclei.
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Affiliation(s)
| | - L Alexis Coon
- Department of Biology, Boston College, Chestnut Hill, MA 02467
| | - Riya Thomas
- Department of Biology, Boston College, Chestnut Hill, MA 02467
| | | | - Elizabeth Wynn
- Department of Biology, Boston College, Chestnut Hill, MA 02467
| | - Eric S Folker
- Department of Biology, Boston College, Chestnut Hill, MA 02467
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12
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Ryniawec JM, Rogers GC. Centrosome instability: when good centrosomes go bad. Cell Mol Life Sci 2021; 78:6775-6795. [PMID: 34476544 PMCID: PMC8560572 DOI: 10.1007/s00018-021-03928-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Revised: 08/10/2021] [Accepted: 08/26/2021] [Indexed: 02/06/2023]
Abstract
The centrosome is a tiny cytoplasmic organelle that organizes and constructs massive molecular machines to coordinate diverse cellular processes. Due to its many roles during both interphase and mitosis, maintaining centrosome homeostasis is essential to normal health and development. Centrosome instability, divergence from normal centrosome number and structure, is a common pathognomonic cellular state tightly associated with cancers and other genetic diseases. As novel connections are investigated linking the centrosome to disease, it is critical to understand the breadth of centrosome functions to inspire discovery. In this review, we provide an introduction to normal centrosome function and highlight recent discoveries that link centrosome instability to specific disease states.
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Affiliation(s)
- John M Ryniawec
- University of Arizona Cancer Center, University of Arizona, 1515 N. Campbell Ave., Tucson, AZ, 85724, USA
| | - Gregory C Rogers
- University of Arizona Cancer Center, University of Arizona, 1515 N. Campbell Ave., Tucson, AZ, 85724, USA.
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13
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Vaishali, Dimitrova-Paternoga L, Haubrich K, Sun M, Ephrussi A, Hennig J. Validation and classification of RNA binding proteins identified by mRNA interactome capture. RNA (NEW YORK, N.Y.) 2021; 27:1173-1185. [PMID: 34215685 PMCID: PMC8456996 DOI: 10.1261/rna.078700.121] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 06/29/2021] [Indexed: 06/13/2023]
Abstract
RNA binding proteins (RBPs) take part in all steps of the RNA life cycle and are often essential for cell viability. Most RBPs have a modular organization and comprise a set of canonical RNA binding domains. However, in recent years a number of high-throughput mRNA interactome studies on yeast, mammalian cell lines, and whole organisms have uncovered a multitude of novel mRNA interacting proteins that lack classical RNA binding domains. Whereas a few have been confirmed to be direct and functionally relevant RNA binders, biochemical and functional validation of RNA binding of most others is lacking. In this study, we used a combination of NMR spectroscopy and biochemical studies to test the RNA binding properties of six putative RBPs. Half of the analyzed proteins showed no interaction, whereas the other half displayed weak chemical shift perturbations upon titration with RNA. One of the candidates we found to interact weakly with RNA in vitro is Drosophila melanogaster end binding protein 1 (EB1), a master regulator of microtubule plus-end dynamics. Further analysis showed that EB1's RNA binding occurs on the same surface as that with which EB1 interacts with microtubules. RNA immunoprecipitation and colocalization experiments suggest that EB1 is a rather nonspecific, opportunistic RNA binder. Our data suggest that care should be taken when embarking on an RNA binding study involving these unconventional, novel RBPs, and we recommend initial and simple in vitro RNA binding experiments.
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Affiliation(s)
- Vaishali
- Developmental Biology Unit, EMBL Heidelberg, 69117 Heidelberg, Germany
- Faculty of Biosciences, Heidelberg University, Heidelberg 69120, Germany
| | - Lyudmila Dimitrova-Paternoga
- Developmental Biology Unit, EMBL Heidelberg, 69117 Heidelberg, Germany
- Structural and Computational Biology Unit, EMBL Heidelberg, 69117 Heidelberg, Germany
| | - Kevin Haubrich
- Structural and Computational Biology Unit, EMBL Heidelberg, 69117 Heidelberg, Germany
| | - Mai Sun
- Genome Biology Unit, EMBL Heidelberg, 69117 Heidelberg, Germany
| | - Anne Ephrussi
- Developmental Biology Unit, EMBL Heidelberg, 69117 Heidelberg, Germany
| | - Janosch Hennig
- Structural and Computational Biology Unit, EMBL Heidelberg, 69117 Heidelberg, Germany
- Biochemistry IV, Biophysical Chemistry, University of Bayreuth, 95447 Bayreuth, Germany
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14
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Sanchez AD, Branon TC, Cote LE, Papagiannakis A, Liang X, Pickett MA, Shen K, Jacobs-Wagner C, Ting AY, Feldman JL. Proximity labeling reveals non-centrosomal microtubule-organizing center components required for microtubule growth and localization. Curr Biol 2021; 31:3586-3600.e11. [PMID: 34242576 PMCID: PMC8478408 DOI: 10.1016/j.cub.2021.06.021] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 04/13/2021] [Accepted: 06/09/2021] [Indexed: 12/24/2022]
Abstract
Microtubules are polarized intracellular polymers that play key roles in the cell, including in transport, polarity, and cell division. Across eukaryotic cell types, microtubules adopt diverse intracellular organization to accommodate these distinct functions coordinated by specific cellular sites called microtubule-organizing centers (MTOCs). Over 50 years of research on MTOC biology has focused mainly on the centrosome; however, most differentiated cells employ non-centrosomal MTOCs (ncMTOCs) to organize their microtubules into diverse arrays, which are critical to cell function. To identify essential ncMTOC components, we developed the biotin ligase-based, proximity-labeling approach TurboID for use in C. elegans. We identified proteins proximal to the microtubule minus end protein PTRN-1/Patronin at the apical ncMTOC of intestinal epithelial cells, focusing on two conserved proteins: spectraplakin protein VAB-10B/MACF1 and WDR-62, a protein we identify as homologous to vertebrate primary microcephaly disease protein WDR62. VAB-10B and WDR-62 do not associate with the centrosome and instead specifically regulate non-centrosomal microtubules and the apical targeting of microtubule minus-end proteins. Depletion of VAB-10B resulted in microtubule mislocalization and delayed localization of a microtubule nucleation complex ɣ-tubulin ring complex (γ-TuRC), while loss of WDR-62 decreased the number of dynamic microtubules and abolished γ-TuRC localization. This regulation occurs downstream of cell polarity and in conjunction with actin. As this is the first report for non-centrosomal roles of WDR62 family proteins, we expand the basic cell biological roles of this important disease protein. Our studies identify essential ncMTOC components and suggest a division of labor where microtubule growth and localization are distinctly regulated.
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Affiliation(s)
- Ariana D Sanchez
- Department of Biology, Stanford University, 371 Serra Mall, Stanford, CA 94305, USA
| | - Tess C Branon
- Department of Biology, Stanford University, 371 Serra Mall, Stanford, CA 94305, USA; Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA; Departments of Genetics and Chemistry, Stanford University, Stanford, CA, USA
| | - Lauren E Cote
- Department of Biology, Stanford University, 371 Serra Mall, Stanford, CA 94305, USA
| | | | - Xing Liang
- Department of Biology, Stanford University, 371 Serra Mall, Stanford, CA 94305, USA; Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA
| | - Melissa A Pickett
- Department of Biology, Stanford University, 371 Serra Mall, Stanford, CA 94305, USA
| | - Kang Shen
- Department of Biology, Stanford University, 371 Serra Mall, Stanford, CA 94305, USA; Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA
| | - Christine Jacobs-Wagner
- Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA; Department of Biology and ChEM-H Institute, Stanford University, Stanford, CA, USA
| | - Alice Y Ting
- Department of Biology, Stanford University, 371 Serra Mall, Stanford, CA 94305, USA; Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA; Departments of Genetics and Chemistry, Stanford University, Stanford, CA, USA; Chan Zuckerberg Biohub, San Francisco, CA, USA
| | - Jessica L Feldman
- Department of Biology, Stanford University, 371 Serra Mall, Stanford, CA 94305, USA.
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15
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Abstract
As one of four filament types, microtubules are a core component of the cytoskeleton and are essential for cell function. Yet how microtubules are nucleated from their building blocks, the αβ-tubulin heterodimer, has remained a fundamental open question since the discovery of tubulin 50 years ago. Recent structural studies have shed light on how γ-tubulin and the γ-tubulin complex proteins (GCPs) GCP2 to GCP6 form the γ-tubulin ring complex (γ-TuRC). In parallel, functional and single-molecule studies have informed on how the γ-TuRC nucleates microtubules in real time, how this process is regulated in the cell and how it compares to other modes of nucleation. Another recent surprise has been the identification of a second essential nucleation factor, which turns out to be the well-characterized microtubule polymerase XMAP215 (also known as CKAP5, a homolog of chTOG, Stu2 and Alp14). This discovery helps to explain why the observed nucleation activity of the γ-TuRC in vitro is relatively low. Taken together, research in recent years has afforded important insight into how microtubules are made in the cell and provides a basis for an exciting era in the cytoskeleton field.
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Affiliation(s)
- Akanksha Thawani
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, Berkeley, CA 94720, USA
| | - Sabine Petry
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
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16
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Panzade S, Matis M. The Microtubule Minus-End Binding Protein Patronin Is Required for the Epithelial Remodeling in the Drosophila Abdomen. Front Cell Dev Biol 2021; 9:682083. [PMID: 34368132 PMCID: PMC8335404 DOI: 10.3389/fcell.2021.682083] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 06/24/2021] [Indexed: 11/29/2022] Open
Abstract
In the developing Drosophila abdomen, the epithelial tissue displays extensive cytoskeletal remodeling. In stark contrast to the spatio-temporal control of the actin cytoskeleton, the regulation of microtubule architecture during epithelial morphogenesis has remained opaque. In particular, its role in cell motility remains unclear. Here, we show that minus-end binding protein Patronin is required for organizing microtubule arrays in histoblast cells that form the Drosophila abdomen. Loss of Patronin results in a dorsal cleft, indicating the compromised function of histoblasts. We further show that Patronin is polarized in these cells and is required for the formation of highly dynamic non-centrosomal microtubules in the migrating histoblasts. Thus, our study demonstrates that regulation of microtubule cytoskeleton through Patronin mediates epithelium remodeling.
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Affiliation(s)
- Sadhana Panzade
- Interfaculty Centre 'Cells in Motion,' University of Münster, Münster, Germany.,Institute of Cell Biology, Medical Faculty, University of Münster, Münster, Germany
| | - Maja Matis
- Interfaculty Centre 'Cells in Motion,' University of Münster, Münster, Germany.,Institute of Cell Biology, Medical Faculty, University of Münster, Münster, Germany
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17
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Abstract
Centrioles are microtubule-based cylindrical structures that assemble the centrosome and template the formation of cilia. The proximal part of centrioles is associated with the pericentriolar material, a protein scaffold from which microtubules are nucleated. This activity is mediated by the γ-tubulin ring complex (γTuRC) whose central role in centrosomal microtubule organization has been recognized for decades. However, accumulating evidence suggests that γTuRC activity at this organelle is neither restricted to the pericentriolar material nor limited to microtubule nucleation. Instead, γTuRC is found along the entire centriole cylinder, at subdistal appendages, and inside the centriole lumen, where its canonical function as a microtubule nucleator might be supplemented or replaced by a function in microtubule anchoring and centriole stabilization, respectively. In this Opinion, we discuss recent insights into the expanded repertoire of γTuRC activities at centrioles and how distinct subpopulations of γTuRC might act in concert to ensure centrosome and cilia biogenesis and function, ultimately supporting cell proliferation, differentiation and homeostasis. We propose that the classical view of centrosomal γTuRC as a pericentriolar material-associated microtubule nucleator needs to be revised.
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Affiliation(s)
- Nina Schweizer
- Mechanisms of Disease Programme, Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology (BIST), Baldiri Reixac 10, 08028 Barcelona, Spain
| | - Jens Lüders
- Mechanisms of Disease Programme, Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology (BIST), Baldiri Reixac 10, 08028 Barcelona, Spain
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18
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Chumová J, Kourová H, Trögelová L, Daniel G, Binarová P. γ-Tubulin Complexes and Fibrillar Arrays: Two Conserved High Molecular Forms with Many Cellular Functions. Cells 2021; 10:cells10040776. [PMID: 33915825 PMCID: PMC8066788 DOI: 10.3390/cells10040776] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 03/29/2021] [Accepted: 03/30/2021] [Indexed: 11/29/2022] Open
Abstract
Higher plants represent a large group of eukaryotes where centrosomes are absent. The functions of γ-tubulin small complexes (γ-TuSCs) and γ-tubulin ring complexes (γ-TuRCs) in metazoans and fungi in microtubule nucleation are well established and the majority of components found in the complexes are present in plants. However, plant microtubules are also nucleated in a γ-tubulin-dependent but γ-TuRC-independent manner. There is growing evidence that γ-tubulin is a microtubule nucleator without being complexed in γ-TuRC. Fibrillar arrays of γ-tubulin were demonstrated in plant and animal cells and the ability of γ-tubulin to assemble into linear oligomers/polymers was confirmed in vitro for both native and recombinant γ-tubulin. The functions of γ-tubulin as a template for microtubule nucleation or in promoting spontaneous nucleation is outlined. Higher plants represent an excellent model for studies on the role of γ-tubulin in nucleation due to their acentrosomal nature and high abundancy and conservation of γ-tubulin including its intrinsic ability to assemble filaments. The defining scaffolding or sequestration functions of plant γ-tubulin in microtubule organization or in nuclear processes will help our understanding of its cellular roles in eukaryotes.
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Affiliation(s)
- Jana Chumová
- Institute of Microbiology of the Czech Academy of Sciences, Vídeňská1083, 142 20 Prague, Czech Republic; (J.C.); (H.K.); (L.T.)
| | - Hana Kourová
- Institute of Microbiology of the Czech Academy of Sciences, Vídeňská1083, 142 20 Prague, Czech Republic; (J.C.); (H.K.); (L.T.)
| | - Lucie Trögelová
- Institute of Microbiology of the Czech Academy of Sciences, Vídeňská1083, 142 20 Prague, Czech Republic; (J.C.); (H.K.); (L.T.)
| | - Geoffrey Daniel
- Department of Biomaterials and Technology/Wood Science, Swedish University of Agricultural Sciences, 750-07 Uppsala, Sweden;
| | - Pavla Binarová
- Institute of Microbiology of the Czech Academy of Sciences, Vídeňská1083, 142 20 Prague, Czech Republic; (J.C.); (H.K.); (L.T.)
- Correspondence: ; Tel.: +420-241-062-130
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19
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Fujii S, Kurokawa K, Tago T, Inaba R, Takiguchi A, Nakano A, Satoh T, Satoh AK. Sec71 separates Golgi stacks in Drosophila S2 cells. J Cell Sci 2020; 133:jcs245571. [PMID: 33262309 PMCID: PMC10668125 DOI: 10.1242/jcs.245571] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 11/18/2020] [Indexed: 01/19/2023] Open
Abstract
Golgi stacks are the basic structural units of the Golgi. Golgi stacks are separated from each other and scattered in the cytoplasm of Drosophila cells. Here, we report that the ARF-GEF inhibitor Brefeldin A (BFA) induces the formation of BFA bodies, which are aggregates of Golgi stacks, trans-Golgi networks and recycling endosomes. Recycling endosomes are located in the centers of BFA bodies, while Golgi stacks surround them on their trans sides. Live imaging of S2 cells revealed that Golgi stacks repeatedly merged and separated on their trans sides, and BFA caused successive merger by inhibiting separation, forming BFA bodies. S2 cells carrying genome-edited BFA-resistant mutant Sec71M717L did not form BFA bodies at high concentrations of BFA; S2 cells carrying genome-edited BFA-hypersensitive mutant Sec71F713Y produced BFA bodies at low concentrations of BFA. These results indicate that Sec71 is the sole BFA target for BFA body formation and controls Golgi stack separation. Finally, we showed that impairment of Sec71 in fly photoreceptors induces BFA body formation, with accumulation of both apical and basolateral cargoes, resulting in inhibition of polarized transport.
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Affiliation(s)
- Syara Fujii
- Program of Life and Environmental Science, Graduate School of Integral Science for Life, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8521, Japan
| | - Kazuo Kurokawa
- Live Cell Super-Resolution Imaging Research Team, RIKEN Center for Advanced Photonics, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Tatsuya Tago
- Program of Life and Environmental Science, Graduate School of Integral Science for Life, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8521, Japan
| | - Ryota Inaba
- Program of Life and Environmental Science, Graduate School of Integral Science for Life, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8521, Japan
| | - Arata Takiguchi
- Program of Life and Environmental Science, Graduate School of Integral Science for Life, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8521, Japan
| | - Akihiko Nakano
- Live Cell Super-Resolution Imaging Research Team, RIKEN Center for Advanced Photonics, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Takunori Satoh
- Program of Life and Environmental Science, Graduate School of Integral Science for Life, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8521, Japan
| | - Akiko K Satoh
- Program of Life and Environmental Science, Graduate School of Integral Science for Life, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8521, Japan
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20
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Thawani A, Rale MJ, Coudray N, Bhabha G, Stone HA, Shaevitz JW, Petry S. The transition state and regulation of γ-TuRC-mediated microtubule nucleation revealed by single molecule microscopy. eLife 2020; 9:e54253. [PMID: 32538784 PMCID: PMC7338055 DOI: 10.7554/elife.54253] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2019] [Accepted: 06/15/2020] [Indexed: 12/31/2022] Open
Abstract
Determining how microtubules (MTs) are nucleated is essential for understanding how the cytoskeleton assembles. While the MT nucleator, γ-tubulin ring complex (γ-TuRC) has been identified, precisely how γ-TuRC nucleates a MT remains poorly understood. Here, we developed a single molecule assay to directly visualize nucleation of a MT from purified Xenopus laevis γ-TuRC. We reveal a high γ-/αβ-tubulin affinity, which facilitates assembly of a MT from γ-TuRC. Whereas spontaneous nucleation requires assembly of 8 αβ-tubulins, nucleation from γ-TuRC occurs efficiently with a cooperativity of 4 αβ-tubulin dimers. This is distinct from pre-assembled MT seeds, where a single dimer is sufficient to initiate growth. A computational model predicts our kinetic measurements and reveals the rate-limiting transition where laterally associated αβ-tubulins drive γ-TuRC into a closed conformation. NME7, TPX2, and the putative activation domain of CDK5RAP2 h γ-TuRC-mediated nucleation, while XMAP215 drastically increases the nucleation efficiency by strengthening the longitudinal γ-/αβ-tubulin interaction.
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Affiliation(s)
- Akanksha Thawani
- Department of Chemical and Biological Engineering, Princeton UniversityPrincetonUnited States
| | - Michael J Rale
- Department of Molecular Biology, Princeton UniversityPrincetonUnited States
| | - Nicolas Coudray
- Department of Cell Biology, New York University School of MedicineNew YorkUnited States
| | - Gira Bhabha
- Department of Cell Biology, New York University School of MedicineNew YorkUnited States
| | - Howard A Stone
- Department of Mechanical and Aerospace Engineering, Princeton UniversityPrincetonUnited States
| | - Joshua W Shaevitz
- Lewis-Sigler Institute for Integrative GenomicsPrincetonUnited States
- Department of Physics, Princeton UniversityPrincetonUnited States
| | - Sabine Petry
- Department of Molecular Biology, Princeton UniversityPrincetonUnited States
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21
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Aydogan MG, Steinacker TL, Mofatteh M, Wilmott ZM, Zhou FY, Gartenmann L, Wainman A, Saurya S, Novak ZA, Wong SS, Goriely A, Boemo MA, Raff JW. An Autonomous Oscillation Times and Executes Centriole Biogenesis. Cell 2020; 181:1566-1581.e27. [PMID: 32531200 PMCID: PMC7327525 DOI: 10.1016/j.cell.2020.05.018] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 12/19/2019] [Accepted: 05/08/2020] [Indexed: 01/18/2023]
Abstract
The accurate timing and execution of organelle biogenesis is crucial for cell physiology. Centriole biogenesis is regulated by Polo-like kinase 4 (Plk4) and initiates in S-phase when a daughter centriole grows from the side of a pre-existing mother. Here, we show that a Plk4 oscillation at the base of the growing centriole initiates and times centriole biogenesis to ensure that centrioles grow at the right time and to the right size. The Plk4 oscillation is normally entrained to the cell-cycle oscillator but can run autonomously of it-potentially explaining why centrioles can duplicate independently of cell-cycle progression. Mathematical modeling indicates that the Plk4 oscillation can be generated by a time-delayed negative feedback loop in which Plk4 inactivates the interaction with its centriolar receptor through multiple rounds of phosphorylation. We hypothesize that similar organelle-specific oscillations could regulate the timing and execution of organelle biogenesis more generally.
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Affiliation(s)
- Mustafa G Aydogan
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK.
| | - Thomas L Steinacker
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - Mohammad Mofatteh
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - Zachary M Wilmott
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK; Mathematical Institute, University of Oxford, Oxford OX2 6GG, UK
| | - Felix Y Zhou
- Ludwig Institute for Cancer Research, University of Oxford, Oxford OX3 7DQ, UK
| | - Lisa Gartenmann
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - Alan Wainman
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - Saroj Saurya
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - Zsofia A Novak
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - Siu-Shing Wong
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - Alain Goriely
- Mathematical Institute, University of Oxford, Oxford OX2 6GG, UK
| | - Michael A Boemo
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK.
| | - Jordan W Raff
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK.
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22
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Galletta BJ, Ortega JM, Smith SL, Fagerstrom CJ, Fear JM, Mahadevaraju S, Oliver B, Rusan NM. Sperm Head-Tail Linkage Requires Restriction of Pericentriolar Material to the Proximal Centriole End. Dev Cell 2020; 53:86-101.e7. [PMID: 32169161 DOI: 10.1016/j.devcel.2020.02.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 11/22/2019] [Accepted: 02/07/2020] [Indexed: 01/27/2023]
Abstract
The centriole, or basal body, is the center of attachment between the sperm head and tail. While the distal end of the centriole templates the cilia, the proximal end associates with the nucleus. Using Drosophila, we identify a centriole-centric mechanism that ensures proper proximal end docking to the nucleus. This mechanism relies on the restriction of pericentrin-like protein (PLP) and the pericentriolar material (PCM) to the proximal end of the centriole. PLP is restricted proximally by limiting its mRNA and protein to the earliest stages of centriole elongation. Ectopic positioning of PLP to more distal portions of the centriole is sufficient to redistribute PCM and microtubules along the entire centriole length. This results in erroneous, lateral centriole docking to the nucleus, leading to spermatid decapitation as a result of a failure to form a stable head-tail linkage.
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Affiliation(s)
- Brian J Galletta
- Cell and Developmental Biology Center, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Jacob M Ortega
- Cell and Developmental Biology Center, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Samantha L Smith
- Cell and Developmental Biology Center, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Carey J Fagerstrom
- Cell and Developmental Biology Center, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Justin M Fear
- Developmental Genomics Section, Laboratory of Cell and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Sharvani Mahadevaraju
- Developmental Genomics Section, Laboratory of Cell and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Brian Oliver
- Developmental Genomics Section, Laboratory of Cell and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Nasser M Rusan
- Cell and Developmental Biology Center, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA.
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23
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Zheng Y, Buchwalter RA, Zheng C, Wight EM, Chen JV, Megraw TL. A perinuclear microtubule-organizing centre controls nuclear positioning and basement membrane secretion. Nat Cell Biol 2020; 22:297-309. [PMID: 32066907 PMCID: PMC7161059 DOI: 10.1038/s41556-020-0470-7] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Accepted: 01/17/2020] [Indexed: 12/22/2022]
Abstract
Non-centrosomal microtubule-organizing centres (ncMTOCs) have a variety of roles presumed to serve the diverse functions of the range of cell types in which they are found. ncMTOCs are diverse in their composition, subcellular localization, and function. Here we report a perinuclear MTOC in Drosophila fat body cells that is anchored by Msp300/Nesprin at the cytoplasmic surface of the nucleus. Msp300 recruits the MT minus-end protein Patronin/CAMSAP, which functions redundantly with Ninein to further recruit the MT polymerase Msps/XMAP215 to assemble non-centrosomal MTs and does so independently of the widespread MT nucleation factor γ-tubulin. Functionally, the fat body ncMTOC and the radial MT arrays it organizes is essential for nuclear positioning and for secretion of basement membrane components via retrograde dynein-dependent endosomal trafficking that restricts plasma membrane growth. Together, this study identifies a perinuclear ncMTOC with unique architecture and MT regulation properties that serves vital functions.
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Affiliation(s)
- Yiming Zheng
- Department of Biomedical Sciences, Florida State University, Tallahassee, FL, USA.
| | - Rebecca A Buchwalter
- Department of Biomedical Sciences, Florida State University, Tallahassee, FL, USA
| | - Chunfeng Zheng
- Department of Biomedical Sciences, Florida State University, Tallahassee, FL, USA
| | - Elise M Wight
- Department of Biomedical Sciences, Florida State University, Tallahassee, FL, USA
| | - Jieyan V Chen
- Department of Biomedical Sciences, Florida State University, Tallahassee, FL, USA.,Neuroscience Research Institute, University of California Santa Barbara, Santa Barbara, CA, USA
| | - Timothy L Megraw
- Department of Biomedical Sciences, Florida State University, Tallahassee, FL, USA.
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Fluorescence correlation spectroscopy reveals the dynamics of kinesins interacting with organelles during microtubule-dependent transport in cells. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2020; 1867:118572. [DOI: 10.1016/j.bbamcr.2019.118572] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 09/04/2019] [Accepted: 09/20/2019] [Indexed: 01/26/2023]
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25
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Affiliation(s)
- Jens Lüders
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain.
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26
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Karabasheva D, Smyth JT. A novel, dynein-independent mechanism focuses the endoplasmic reticulum around spindle poles in dividing Drosophila spermatocytes. Sci Rep 2019; 9:12456. [PMID: 31462700 PMCID: PMC6713755 DOI: 10.1038/s41598-019-48860-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Accepted: 08/14/2019] [Indexed: 01/04/2023] Open
Abstract
In dividing animal cells the endoplasmic reticulum (ER) concentrates around the poles of the spindle apparatus by associating with astral microtubules (MTs), and this association is essential for proper ER partitioning to progeny cells. The mechanisms that associate the ER with astral MTs are unknown. Because astral MT minus-ends are anchored by centrosomes at spindle poles, we hypothesized that the MT minus-end motor dynein mediates ER concentration around spindle poles. Live in vivo imaging of Drosophila spermatocytes revealed that dynein is required for ER concentration around centrosomes during late interphase. In marked contrast, however, dynein suppression had no effect on ER association with astral MTs and concentration around spindle poles in early M-phase. In fact, there was a sudden onset of ER association with astral MTs in dynein RNAi cells, revealing activation of an M-phase specific mechanism of ER-MT association. ER redistribution to spindle poles also did not require non-claret disjunctional (ncd), the other known Drosophila MT minus-end motor, nor Klp61F, a MT plus-end motor that generates spindle poleward forces. Collectively, our results suggest that a novel, M-phase specific mechanism of ER-MT association that is independent of MT minus-end motors is required for proper ER partitioning in dividing cells.
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Affiliation(s)
- Darya Karabasheva
- Department of Anatomy, Physiology, and Genetics, Uniformed Services University of the Health Sciences, F. Edward Hébert School of Medicine, Bethesda, MD, 20814, USA
| | - Jeremy T Smyth
- Department of Anatomy, Physiology, and Genetics, Uniformed Services University of the Health Sciences, F. Edward Hébert School of Medicine, Bethesda, MD, 20814, USA.
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Joukov V, De Nicolo A. The Centrosome and the Primary Cilium: The Yin and Yang of a Hybrid Organelle. Cells 2019; 8:E701. [PMID: 31295970 PMCID: PMC6678760 DOI: 10.3390/cells8070701] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 07/04/2019] [Accepted: 07/06/2019] [Indexed: 12/27/2022] Open
Abstract
Centrosomes and primary cilia are usually considered as distinct organelles, although both are assembled with the same evolutionary conserved, microtubule-based templates, the centrioles. Centrosomes serve as major microtubule- and actin cytoskeleton-organizing centers and are involved in a variety of intracellular processes, whereas primary cilia receive and transduce environmental signals to elicit cellular and organismal responses. Understanding the functional relationship between centrosomes and primary cilia is important because defects in both structures have been implicated in various diseases, including cancer. Here, we discuss evidence that the animal centrosome evolved, with the transition to complex multicellularity, as a hybrid organelle comprised of the two distinct, but intertwined, structural-functional modules: the centriole/primary cilium module and the pericentriolar material/centrosome module. The evolution of the former module may have been caused by the expanding cellular diversification and intercommunication, whereas that of the latter module may have been driven by the increasing complexity of mitosis and the requirement for maintaining cell polarity, individuation, and adhesion. Through its unique ability to serve both as a plasma membrane-associated primary cilium organizer and a juxtanuclear microtubule-organizing center, the animal centrosome has become an ideal integrator of extracellular and intracellular signals with the cytoskeleton and a switch between the non-cell autonomous and the cell-autonomous signaling modes. In light of this hypothesis, we discuss centrosome dynamics during cell proliferation, migration, and differentiation and propose a model of centrosome-driven microtubule assembly in mitotic and interphase cells. In addition, we outline the evolutionary benefits of the animal centrosome and highlight the hierarchy and modularity of the centrosome biogenesis networks.
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Affiliation(s)
- Vladimir Joukov
- N.N. Petrov National Medical Research Center of Oncology, 197758 Saint-Petersburg, Russia.
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28
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Raff JW. Phase Separation and the Centrosome: A Fait Accompli? Trends Cell Biol 2019; 29:612-622. [PMID: 31076235 DOI: 10.1016/j.tcb.2019.04.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 04/08/2019] [Accepted: 04/08/2019] [Indexed: 12/28/2022]
Abstract
There is currently intense interest in the idea that many membraneless organelles might assemble through phase separation of their constituent molecules into biomolecular 'condensates' that have liquid-like properties. This idea is intuitively appealing, especially for complex organelles such as centrosomes, where a liquid-like structure would allow the many constituent molecules to diffuse and interact with one another efficiently. I discuss here recent studies that either support the concept of a liquid-like centrosome or suggest that centrosomes are assembled upon a more solid, stable scaffold. I suggest that it may be difficult to distinguish between these possibilities. I argue that the concept of biomolecular condensates is an important advance in cell biology, with potentially wide-ranging implications, but it seems premature to conclude that centrosomes, and perhaps other membraneless organelles, are necessarily best described as liquid-like phase-separated condensates.
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Affiliation(s)
- Jordan W Raff
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK.
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29
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TAPping into the treasures of tubulin using novel protein production methods. Essays Biochem 2018; 62:781-792. [PMID: 30429282 PMCID: PMC6281476 DOI: 10.1042/ebc20180033] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 10/03/2018] [Accepted: 10/22/2018] [Indexed: 01/02/2023]
Abstract
Microtubules are cytoskeletal elements with important cellular functions, whose dynamic behaviour and properties are in part regulated by microtubule-associated proteins (MAPs). The building block of microtubules is tubulin, a heterodimer of α- and β-tubulin subunits. Longitudinal interactions between tubulin dimers facilitate a head-to-tail arrangement of dimers into protofilaments, while lateral interactions allow the formation of a hollow microtubule tube that mostly contains 13 protofilaments. Highly homologous α- and β-tubulin isotypes exist, which are encoded by multi-gene families. In vitro studies on microtubules and MAPs have largely relied on brain-derived tubulin preparations. However, these consist of an unknown mix of tubulin isotypes with undefined post-translational modifications. This has blocked studies on the functions of tubulin isotypes and the effects of tubulin mutations found in human neurological disorders. Fortunately, various methodologies to produce recombinant mammalian tubulins have become available in the last years, allowing researchers to overcome this barrier. In addition, affinity-based purification of tagged tubulins and identification of tubulin-associated proteins (TAPs) by mass spectrometry has revealed the 'tubulome' of mammalian cells. Future experiments with recombinant tubulins should allow a detailed description of how tubulin isotype influences basic microtubule behaviour, and how MAPs and TAPs impinge on tubulin isotypes and microtubule-based processes in different cell types.
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30
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Microtubule nucleation by γ-tubulin complexes and beyond. Essays Biochem 2018; 62:765-780. [PMID: 30315097 PMCID: PMC6281477 DOI: 10.1042/ebc20180028] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2018] [Revised: 09/05/2018] [Accepted: 09/13/2018] [Indexed: 12/21/2022]
Abstract
In this short review, we give an overview of microtubule nucleation within cells. It is nearly 30 years since the discovery of γ-tubulin, a member of the tubulin superfamily essential for proper microtubule nucleation in all eukaryotes. γ-tubulin associates with other proteins to form multiprotein γ-tubulin ring complexes (γ-TuRCs) that template and catalyse the otherwise kinetically unfavourable assembly of microtubule filaments. These filaments can be dynamic or stable and they perform diverse functions, such as chromosome separation during mitosis and intracellular transport in neurons. The field has come a long way in understanding γ-TuRC biology but several important and unanswered questions remain, and we are still far from understanding the regulation of microtubule nucleation in a multicellular context. Here, we review the current literature on γ-TuRC assembly, recruitment, and activation and discuss the potential importance of γ-TuRC heterogeneity, the role of non-γ-TuRC proteins in microtubule nucleation, and whether γ-TuRCs could serve as good drug targets for cancer therapy.
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31
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Molines AT, Marion J, Chabout S, Besse L, Dompierre JP, Mouille G, Coquelle FM. EB1 contributes to microtubule bundling and organization, along with root growth, in Arabidopsis thaliana. Biol Open 2018; 7:bio.030510. [PMID: 29945874 PMCID: PMC6124560 DOI: 10.1242/bio.030510] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Microtubules are involved in plant development and adaptation to their environment, but the sustaining molecular mechanisms remain elusive. Microtubule-end-binding 1 (EB1) proteins participate in directional root growth in Arabidopsis thaliana. However, a connection to the underlying microtubule array has not been established yet. We show here that EB1 proteins contribute to the organization of cortical microtubules in growing epidermal plant cells, without significant modulation of microtubule dynamics. Using super-resolution stimulated emission depletion (STED) microscopy and an original quantification approach, we also demonstrate a significant reduction of apparent microtubule bundling in cytoplasmic-EB1-deficient plants, suggesting a function for EB1 in the interaction between adjacent microtubules. Furthermore, we observed root growth defects in EB1-deficient plants, which are not related to cell division impairment. Altogether, our results support a role for EB1 proteins in root development, in part by maintaining the organization of cortical microtubules. This article has an associated First Person interview with the first author of the paper. Summary: EB1 proteins affect cortical-microtubule bundling and organization in Arabidopsis thaliana, without significant modulation of microtubule dynamics. They also participate in root growth, further linking microtubules to plant development.
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Affiliation(s)
- Arthur T Molines
- Department of Cell Biology, Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette Cedex, France
| | - Jessica Marion
- Department of Cell Biology, Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette Cedex, France
| | - Salem Chabout
- Institut Jean-Pierre Bourgin (IJPB), INRA - AgroParisTech, 78026 Versailles Cedex, France
| | - Laetitia Besse
- Light Microscopy Facility, Imagerie-Gif, Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette Cedex, France
| | - Jim P Dompierre
- Light Microscopy Facility, Imagerie-Gif, Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette Cedex, France
| | - Grégory Mouille
- Institut Jean-Pierre Bourgin (IJPB), INRA - AgroParisTech, 78026 Versailles Cedex, France
| | - Frédéric M Coquelle
- Department of Cell Biology, Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette Cedex, France
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32
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Sallee MD, Zonka JC, Skokan TD, Raftrey BC, Feldman JL. Tissue-specific degradation of essential centrosome components reveals distinct microtubule populations at microtubule organizing centers. PLoS Biol 2018; 16:e2005189. [PMID: 30080857 PMCID: PMC6103517 DOI: 10.1371/journal.pbio.2005189] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 08/21/2018] [Accepted: 07/20/2018] [Indexed: 11/19/2022] Open
Abstract
Non-centrosomal microtubule organizing centers (ncMTOCs) are found in most differentiated cells, but how these structures regulate microtubule organization and dynamics is largely unknown. We optimized a tissue-specific degradation system to test the role of the essential centrosomal microtubule nucleators γ-tubulin ring complex (γ-TuRC) and AIR-1/Aurora A at the apical ncMTOC, where they both localize in Caenorhabditis elegans embryonic intestinal epithelial cells. As at the centrosome, the core γ-TuRC component GIP-1/GCP3 is required to recruit other γ-TuRC components to the apical ncMTOC, including MZT-1/MZT1, characterized here for the first time in animal development. In contrast, AIR-1 and MZT-1 were specifically required to recruit γ-TuRC to the centrosome, but not to centrioles or to the apical ncMTOC. Surprisingly, microtubules remain robustly organized at the apical ncMTOC upon γ-TuRC and AIR-1 co-depletion, and upon depletion of other known microtubule regulators, including TPXL-1/TPX2, ZYG-9/ch-TOG, PTRN-1/CAMSAP, and NOCA-1/Ninein. However, loss of GIP-1 removed a subset of dynamic EBP-2/EB1-marked microtubules, and the remaining dynamic microtubules grew faster. Together, these results suggest that different microtubule organizing centers (MTOCs) use discrete proteins for their function, and that the apical ncMTOC is composed of distinct populations of γ-TuRC-dependent and -independent microtubules that compete for a limited pool of resources.
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Affiliation(s)
- Maria D. Sallee
- Department of Biology, Stanford University, Stanford, California, United States of America
| | - Jennifer C. Zonka
- Department of Biology, Stanford University, Stanford, California, United States of America
| | - Taylor D. Skokan
- Department of Biology, Stanford University, Stanford, California, United States of America
| | - Brian C. Raftrey
- Department of Biology, Stanford University, Stanford, California, United States of America
| | - Jessica L. Feldman
- Department of Biology, Stanford University, Stanford, California, United States of America
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33
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Strunov A, Boldyreva LV, Andreyeva EN, Pavlova GA, Popova JV, Razuvaeva AV, Anders AF, Renda F, Pindyurin AV, Gatti M, Kiseleva E. Ultrastructural analysis of mitotic Drosophila S2 cells identifies distinctive microtubule and intracellular membrane behaviors. BMC Biol 2018; 16:68. [PMID: 29907103 PMCID: PMC6003134 DOI: 10.1186/s12915-018-0528-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Accepted: 05/08/2018] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND S2 cells are one of the most widely used Drosophila melanogaster cell lines. A series of studies has shown that they are particularly suitable for RNAi-based screens aimed at the dissection of cellular pathways, including those controlling cell shape and motility, cell metabolism, and host-pathogen interactions. In addition, RNAi in S2 cells has been successfully used to identify many new mitotic genes that are conserved in the higher eukaryotes, and for the analysis of several aspects of the mitotic process. However, no detailed and complete description of S2 cell mitosis at the ultrastructural level has been done. Here, we provide a detailed characterization of all phases of S2 cell mitosis visualized by transmission electron microscopy (TEM). RESULTS We analyzed by TEM a random sample of 144 cells undergoing mitosis, focusing on intracellular membrane and microtubule (MT) behaviors. This unbiased approach provided a comprehensive ultrastructural view of the dividing cells, and allowed us to discover that S2 cells exhibit a previously uncharacterized behavior of intracellular membranes, involving the formation of a quadruple nuclear membrane in early prometaphase and its disassembly during late prometaphase. After nuclear envelope disassembly, the mitotic apparatus becomes encased by a discontinuous network of endoplasmic reticulum membranes, which associate with mitochondria, presumably to prevent their diffusion into the spindle area. We also observed a peculiar metaphase spindle organization. We found that kinetochores with attached k-fibers are almost invariably associated with lateral MT bundles that can be either interpolar bundles or k-fibers connected to a different kinetochore. This spindle organization is likely to favor chromosome alignment at metaphase and subsequent segregation during anaphase. CONCLUSIONS We discovered several previously unknown features of membrane and MT organization during S2 cell mitosis. The genetic determinants of these mitotic features can now be investigated, for instance by using an RNAi-based approach, which is particularly easy and efficient in S2 cells.
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Affiliation(s)
- Anton Strunov
- Institute of Molecular and Cellular Biology, Siberian Branch of RAS, Novosibirsk, 630090, Russia.
- Institute of Cytology and Genetics, Siberian Branch of RAS, Novosibirsk, 630090, Russia.
| | - Lidiya V Boldyreva
- Institute of Molecular and Cellular Biology, Siberian Branch of RAS, Novosibirsk, 630090, Russia
| | - Evgeniya N Andreyeva
- Institute of Molecular and Cellular Biology, Siberian Branch of RAS, Novosibirsk, 630090, Russia
| | - Gera A Pavlova
- Institute of Molecular and Cellular Biology, Siberian Branch of RAS, Novosibirsk, 630090, Russia
| | - Julia V Popova
- Institute of Molecular and Cellular Biology, Siberian Branch of RAS, Novosibirsk, 630090, Russia
- Institute of Cytology and Genetics, Siberian Branch of RAS, Novosibirsk, 630090, Russia
| | - Alena V Razuvaeva
- Institute of Molecular and Cellular Biology, Siberian Branch of RAS, Novosibirsk, 630090, Russia
- Novosibirsk State University, Novosibirsk, 630090, Russia
| | - Alina F Anders
- Institute of Molecular and Cellular Biology, Siberian Branch of RAS, Novosibirsk, 630090, Russia
- Novosibirsk State University, Novosibirsk, 630090, Russia
| | - Fioranna Renda
- IBPM CNR and Department of Biology and Biotechnology, Sapienza University of Rome, 00185, Rome, Italy
- Present address: Wadsworth Center, New York State Department of Health, Albany, NY, 12201, USA
| | - Alexey V Pindyurin
- Institute of Molecular and Cellular Biology, Siberian Branch of RAS, Novosibirsk, 630090, Russia
- Institute of Cytology and Genetics, Siberian Branch of RAS, Novosibirsk, 630090, Russia
- Novosibirsk State University, Novosibirsk, 630090, Russia
| | - Maurizio Gatti
- Institute of Molecular and Cellular Biology, Siberian Branch of RAS, Novosibirsk, 630090, Russia.
- IBPM CNR and Department of Biology and Biotechnology, Sapienza University of Rome, 00185, Rome, Italy.
| | - Elena Kiseleva
- Institute of Molecular and Cellular Biology, Siberian Branch of RAS, Novosibirsk, 630090, Russia
- Institute of Cytology and Genetics, Siberian Branch of RAS, Novosibirsk, 630090, Russia
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34
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Thawani A, Kadzik RS, Petry S. XMAP215 is a microtubule nucleation factor that functions synergistically with the γ-tubulin ring complex. Nat Cell Biol 2018; 20:575-585. [PMID: 29695792 PMCID: PMC5926803 DOI: 10.1038/s41556-018-0091-6] [Citation(s) in RCA: 99] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 03/20/2018] [Indexed: 12/16/2022]
Abstract
How microtubules (MTs) are generated in the cell is a major question in understanding how the cytoskeleton is assembled. For several decades, γ-tubulin has been accepted as the universal MT nucleator of the cell. Although there is evidence that γ-tubulin complexes are not the sole MT nucleators, identification of other nucleation factors has proven difficult. Here, we report that the well-characterized MT polymerase XMAP215 (chTOG/Msps/Stu2p/Alp14/Dis1 homologue) is essential for MT nucleation in Xenopus egg extracts. The concentration of XMAP215 determines the extent of MT nucleation. Even though XMAP215 and the γ-tubulin ring complex (γ-TuRC) possess minimal nucleation activity individually, together, these factors synergistically stimulate MT nucleation in vitro. The amino-terminal TOG domains 1-5 of XMAP215 bind to αβ-tubulin and promote MT polymerization, whereas the conserved carboxy terminus is required for efficient MT nucleation and directly binds to γ-tubulin. In summary, XMAP215 and γ-TuRC together function as the principal nucleation module that generates MTs in cells.
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Affiliation(s)
- Akanksha Thawani
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA
| | - Rachel S Kadzik
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Sabine Petry
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA.
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35
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Zvorykina Y, Tvorogova A, Gladkikh A, Vorobjev I. Non-centrosomal MTs play a crucial role in organization of MT array in interphase fibroblasts. AIMS GENETICS 2018; 5:141-160. [PMID: 31435518 PMCID: PMC6698575 DOI: 10.3934/genet.2018.2.141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 03/15/2018] [Indexed: 11/30/2022]
Abstract
Microtubules in interphase fibroblast-like cells are thought to be organized in a radial array growing from a centrosome-based microtubule-organizing center (MTOC) to the cell edges. However, many morphogenetic processes require the asymmetry of the microtubules (MT) array. One of the possible mechanisms of this asymmetry could be the presence of non-centrosomal microtubules in different intracellular areas. To evaluate the role of centrosome-born and non-centrosomal microtubules in the organization of microtubule array in motile 3T3 fibroblasts, we have performed the high-throughput analysis of microtubule growth in different functional zones of the cell and distinguished three subpopulations of growing microtubules (centrosome-born, marginal and inner cytoplasmic). Centrosome as an active microtubule-organizing center was absent in half of the cell population. However, these cells do not show any difference in microtubule growth pattern. In cells with active centrosome, it was constantly forming short (ephemeral) MTs, and ∼15–20 MT per minute grow outwards for a distance >1 µm. Almost no persistent growth of microtubules was observed in these cells with the average growth length of 5–6 µm and duration of growth periods within 30 s. However, the number of growing ends increased towards cell margin, especially towards the active edges. We found the peripheral cytoplasmic foci of microtubule growth there. During recovery from nocodazole treatment microtubules started to grow around the centrosome in a normal way and independently in all the cell areas. Within 5 minutes microtubules continued to grow mainly near the cell edge. Thus, our data confirm the negligible role of centrosome as MTOC in 3T3 fibroblasts and propose a model of non-centrosomal microtubules as major players that create the cell asymmetry in the cells with a mesenchymal type of motility. We suggest that increased density of dynamic microtubules near the active lamellum could be supported by microtubule-based microtubule nucleation.
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Affiliation(s)
| | - Anna Tvorogova
- A.N. Belozersky Institute of Physico-Chemical Biology, M.V. Lomonosov Moscow State University, Moscow, Russia
| | - Aleena Gladkikh
- Biology Department, M.V. Lomonosov Moscow State University, Moscow, Russia
| | - Ivan Vorobjev
- Biology Department, M.V. Lomonosov Moscow State University, Moscow, Russia.,A.N. Belozersky Institute of Physico-Chemical Biology, M.V. Lomonosov Moscow State University, Moscow, Russia.,School of Science and Technology, and National Laboratory Astana, Nazarbayev University, Astana, Kazakhstan
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36
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Microtubule-Organizing Centers: Towards a Minimal Parts List. Trends Cell Biol 2017; 28:176-187. [PMID: 29173799 DOI: 10.1016/j.tcb.2017.10.005] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Revised: 10/20/2017] [Accepted: 10/23/2017] [Indexed: 12/17/2022]
Abstract
Despite decades of molecular analysis of the centrosome, an important microtubule-organizing center (MTOC) of animal cells, the molecular basis of microtubule organization remains obscure. A major challenge is the sheer complexity of the interplay of the hundreds of proteins that constitute the centrosome. However, this complexity owes not only to the centrosome's role as a MTOC but also to the requirements of its duplication cycle and to various other functions such as the formation of cilia, the integration of various signaling pathways, and the organization of actin filaments. Thus, rather than using the parts lists to reconstruct the centrosome, we propose to identify the subset of proteins minimally needed to assemble a MTOC and to study this process at non-centrosomal sites.
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37
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Abstract
The scaffold protein Par-3 (
Drosophila Bazooka) is a central organizer of cell polarity across animals. This review focuses on how the clustering of Par-3 contributes to cell polarity. It begins with the Par-3 homo-oligomerization mechanism and its regulation by Par-1 phosphorylation. The role of polarized cytoskeletal networks in distributing Par-3 clusters to one end of the cell is then discussed, as is the subsequent maintenance of polarized Par-3 clusters through hindered mobility and inhibition from the opposite pole. Finally, specific roles of Par-3 clusters are reviewed, including the bundling of microtubules, the cortical docking of centrosomes, the growth and positioning of cadherin–catenin clusters, and the inhibition of the Par-6–aPKC kinase cassette. Examples are drawn from
Drosophila, Caenorhabditis elegans, mammalian cell culture, and biochemical studies.
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Affiliation(s)
- Tony J C Harris
- Department of Cell & Systems Biology, University of Toronto, Toronto, Canada
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38
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Roostalu J, Surrey T. Microtubule nucleation: beyond the template. Nat Rev Mol Cell Biol 2017; 18:702-710. [PMID: 28831203 DOI: 10.1038/nrm.2017.75] [Citation(s) in RCA: 115] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Microtubules are cytoskeletal filaments central to a wide range of essential cellular functions in eukaryotic cells. Consequently, cells need to exert tight control over when, where and how many microtubules are being made. Whereas the regulation of microtubule dynamics is well studied, the molecular mechanisms of microtubule nucleation are still poorly understood. Next to the established master template of nucleation, the γ-tubulin ring complex, other microtubule-associated proteins that affect microtubule dynamic properties have recently been found to contribute to nucleation. It has begun to emerge that the nucleation efficiency is controlled not only by template activity but also by, either additionally or alternatively, the stabilization of the nascent microtubule 'nucleus'. This suggests a simple conceptual framework for the mechanisms regulating microtubule nucleation in cells.
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Affiliation(s)
| | - Thomas Surrey
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
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39
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Feng Z, Caballe A, Wainman A, Johnson S, Haensele AFM, Cottee MA, Conduit PT, Lea SM, Raff JW. Structural Basis for Mitotic Centrosome Assembly in Flies. Cell 2017; 169:1078-1089.e13. [PMID: 28575671 PMCID: PMC5457487 DOI: 10.1016/j.cell.2017.05.030] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Revised: 03/23/2017] [Accepted: 05/15/2017] [Indexed: 11/16/2022]
Abstract
In flies, Centrosomin (Cnn) forms a phosphorylation-dependent scaffold that recruits proteins to the mitotic centrosome, but how Cnn assembles into a scaffold is unclear. We show that scaffold assembly requires conserved leucine zipper (LZ) and Cnn-motif 2 (CM2) domains that co-assemble into a 2:2 complex in vitro. We solve the crystal structure of the LZ:CM2 complex, revealing that both proteins form helical dimers that assemble into an unusual tetramer. A slightly longer version of the LZ can form micron-scale structures with CM2, whose assembly is stimulated by Plk1 phosphorylation in vitro. Mutating individual residues that perturb LZ:CM2 tetramer assembly perturbs the formation of these micron-scale assemblies in vitro and Cnn-scaffold assembly in vivo. Thus, Cnn molecules have an intrinsic ability to form large, LZ:CM2-interaction-dependent assemblies that are critical for mitotic centrosome assembly. These studies provide the first atomic insight into a molecular interaction required for mitotic centrosome assembly. The conserved PReM and CM2 domains of Cnn co-assemble into micron-scale structures The crystal structure of the PReM-LZ:CM2 complex is solved to 1.82 Å Mutations that block PReM-LZ:CM2 assembly in vitro block centrosome assembly in vivo Phosphorylation of PReM by Polo/Plk1 promotes scaffold assembly in vitro and in vivo
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Affiliation(s)
- Zhe Feng
- The Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Anna Caballe
- The Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Alan Wainman
- The Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Steven Johnson
- The Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Andreas F M Haensele
- The Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Matthew A Cottee
- The Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Paul T Conduit
- The Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Susan M Lea
- The Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK.
| | - Jordan W Raff
- The Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK.
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40
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Abstract
The organization of microtubule networks is crucial for controlling chromosome segregation during cell division, for positioning and transport of different organelles, and for cell polarity and morphogenesis. The geometry of microtubule arrays strongly depends on the localization and activity of the sites where microtubules are nucleated and where their minus ends are anchored. Such sites are often clustered into structures known as microtubule-organizing centers, which include the centrosomes in animals and spindle pole bodies in fungi. In addition, other microtubules, as well as membrane compartments such as the cell nucleus, the Golgi apparatus, and the cell cortex, can nucleate, stabilize, and tether microtubule minus ends. These activities depend on microtubule-nucleating factors, such as γ-tubulin-containing complexes and their activators and receptors, and microtubule minus end-stabilizing proteins with their binding partners. Here, we provide an overview of the current knowledge on how such factors work together to control microtubule organization in different systems.
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Affiliation(s)
- Jingchao Wu
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, 3584 Utrecht, The Netherlands; ,
| | - Anna Akhmanova
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, 3584 Utrecht, The Netherlands; ,
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41
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Nashchekin D, Fernandes AR, St Johnston D. Patronin/Shot Cortical Foci Assemble the Noncentrosomal Microtubule Array that Specifies the Drosophila Anterior-Posterior Axis. Dev Cell 2017; 38:61-72. [PMID: 27404359 PMCID: PMC4943857 DOI: 10.1016/j.devcel.2016.06.010] [Citation(s) in RCA: 108] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 05/03/2016] [Accepted: 06/08/2016] [Indexed: 02/06/2023]
Abstract
Noncentrosomal microtubules play an important role in polarizing differentiated cells, but little is known about how these microtubules are organized. Here we identify the spectraplakin, Short stop (Shot), as the cortical anchor for noncentrosomal microtubule organizing centers (ncMTOCs) in the Drosophila oocyte. Shot interacts with the cortex through its actin-binding domain and recruits the microtubule minus-end-binding protein, Patronin, to form cortical ncMTOCs. Shot/Patronin foci do not co-localize with γ-tubulin, suggesting that they do not nucleate new microtubules. Instead, they capture and stabilize existing microtubule minus ends, which then template new microtubule growth. Shot/Patronin foci are excluded from the oocyte posterior by the Par-1 polarity kinase to generate the polarized microtubule network that localizes axis determinants. Both proteins also accumulate apically in epithelial cells, where they are required for the formation of apical-basal microtubule arrays. Thus, Shot/Patronin ncMTOCs may provide a general mechanism for organizing noncentrosomal microtubules in differentiated cells. The Drosophila spectraplakin, Shot, recruits Patronin to form noncentrosomal MTOCs The actin-binding domain of Shot anchors the ncMTOCs to the oocyte cortex Par-1 excludes Shot from the posterior cortex to define the anterior-posterior axis Shot/Patronin ncMTOCs lack γ-tubulin and grow MTs from stabilized minus-end stumps
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Affiliation(s)
- Dmitry Nashchekin
- The Gurdon Institute and the Department of Genetics, the University of Cambridge, Cambridge CB2 1QN, UK
| | - Artur Ribeiro Fernandes
- The Gurdon Institute and the Department of Genetics, the University of Cambridge, Cambridge CB2 1QN, UK
| | - Daniel St Johnston
- The Gurdon Institute and the Department of Genetics, the University of Cambridge, Cambridge CB2 1QN, UK.
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42
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Carvajal-Gonzalez JM, Mulero-Navarro S, Mlodzik M. Centriole positioning in epithelial cells and its intimate relationship with planar cell polarity. Bioessays 2016; 38:1234-1245. [PMID: 27774671 DOI: 10.1002/bies.201600154] [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] [Indexed: 12/13/2022]
Abstract
Planar cell polarity (PCP)-signaling and associated tissue polarization are evolutionarily conserved. A well documented feature of PCP-signaling in vertebrates is its link to centriole/cilia positioning, although the relationship of PCP and ciliogenesis is still debated. A recent report in Drosophila established that Frizzled (Fz)-PCP core signaling has an instructive input to polarized centriole positioning in non-ciliated Drosophila wing epithelia as a PCP read-out. Here, we review the impact of this observation in the context of recent descriptions of the relationship(s) of core Fz-PCP signaling and cilia/centriole positioning in epithelial and non-epithelial cells. All existing data are consistent with a model where Fz-PCP signaling functions upstream of centriole/cilia positioning, independent of ciliogenesis. The combined data sets indicate that the Fz-Dsh PCP complex is instructive for centriole/ciliary positioning via an actin-based mechanism. Thereby, centriole/cilia/centrosome positioning can be considered an evolutionarily conserved readout and common downstream effect of PCP-signaling from flies to mammals.
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Affiliation(s)
- Jose Maria Carvajal-Gonzalez
- Departamento de Bioquímica, Biología Molecular y Genética, Facultad de Ciencias, Universidad de Extremadura, Badajoz, Spain
| | - Sonia Mulero-Navarro
- Departamento de Bioquímica, Biología Molecular y Genética, Facultad de Ciencias, Universidad de Extremadura, Badajoz, Spain
| | - Marek Mlodzik
- Department of Developmental and Regenerative Biology and Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
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43
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Sanchez AD, Feldman JL. Microtubule-organizing centers: from the centrosome to non-centrosomal sites. Curr Opin Cell Biol 2016; 44:93-101. [PMID: 27666167 DOI: 10.1016/j.ceb.2016.09.003] [Citation(s) in RCA: 154] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 08/19/2016] [Accepted: 09/08/2016] [Indexed: 11/25/2022]
Abstract
The process of cellular differentiation requires the distinct spatial organization of the microtubule cytoskeleton, the arrangement of which is specific to cell type. Microtubule patterning does not occur randomly, but is imparted by distinct subcellular sites called microtubule-organizing centers (MTOCs). Since the discovery of MTOCs fifty years ago, their study has largely focused on the centrosome. All animal cells use centrosomes as MTOCs during mitosis. However in many differentiated cells, MTOC function is reassigned to non-centrosomal sites to generate non-radial microtubule organization better suited for new cell functions, such as mechanical support or intracellular transport. Here, we review the current understanding of non-centrosomal MTOCs (ncMTOCs) and the mechanisms by which they form in differentiating animal cells.
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Affiliation(s)
- Ariana D Sanchez
- Department of Biology, Stanford University, 371 Serra Mall, Stanford, CA 94305, USA
| | - Jessica L Feldman
- Department of Biology, Stanford University, 371 Serra Mall, Stanford, CA 94305, USA.
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44
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A centrosome interactome provides insight into organelle assembly and reveals a non-duplication role for Plk4. Nat Commun 2016; 7:12476. [PMID: 27558293 PMCID: PMC5007297 DOI: 10.1038/ncomms12476] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Accepted: 07/05/2016] [Indexed: 02/06/2023] Open
Abstract
The centrosome is the major microtubule-organizing centre of many cells, best known for its role in mitotic spindle organization. How the proteins of the centrosome are accurately assembled to carry out its many functions remains poorly understood. The non-membrane-bound nature of the centrosome dictates that protein-protein interactions drive its assembly and functions. To investigate this massive macromolecular organelle, we generated a 'domain-level' centrosome interactome using direct protein-protein interaction data from a focused yeast two-hybrid screen. We then used biochemistry, cell biology and the model organism Drosophila to provide insight into the protein organization and kinase regulatory machinery required for centrosome assembly. Finally, we identified a novel role for Plk4, the master regulator of centriole duplication. We show that Plk4 phosphorylates Cep135 to properly position the essential centriole component Asterless. This interaction landscape affords a critical framework for research of normal and aberrant centrosomes.
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45
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Sysoev VO, Fischer B, Frese CK, Gupta I, Krijgsveld J, Hentze MW, Castello A, Ephrussi A. Global changes of the RNA-bound proteome during the maternal-to-zygotic transition in Drosophila. Nat Commun 2016; 7:12128. [PMID: 27378189 PMCID: PMC4935972 DOI: 10.1038/ncomms12128] [Citation(s) in RCA: 106] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Accepted: 06/03/2016] [Indexed: 12/15/2022] Open
Abstract
The maternal-to-zygotic transition (MZT) is a process that occurs in animal embryos at the earliest developmental stages, during which maternally deposited mRNAs and other molecules are degraded and replaced by products of the zygotic genome. The zygotic genome is not activated immediately upon fertilization, and in the pre-MZT embryo post-transcriptional control by RNA-binding proteins (RBPs) orchestrates the first steps of development. To identify relevant Drosophila RBPs organism-wide, we refined the RNA interactome capture method for comparative analysis of the pre- and post-MZT embryos. We determine 523 proteins as high-confidence RBPs, half of which were not previously reported to bind RNA. Comparison of the RNA interactomes of pre- and post-MZT embryos reveals high dynamicity of the RNA-bound proteome during early development, and suggests active regulation of RNA binding of some RBPs. This resource provides unprecedented insight into the system of RBPs that govern the earliest steps of Drosophila development.
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Affiliation(s)
- Vasiliy O. Sysoev
- European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Bernd Fischer
- European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
- German Cancer Research Center, Im Neuenheimer Feld 580, 69120 Heidelberg, Germany
| | - Christian K. Frese
- European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Ishaan Gupta
- European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Jeroen Krijgsveld
- European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Matthias W. Hentze
- European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Alfredo Castello
- European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, England
| | - Anne Ephrussi
- European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
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46
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Smyth JT, Schoborg TA, Bergman ZJ, Riggs B, Rusan NM. Proper symmetric and asymmetric endoplasmic reticulum partitioning requires astral microtubules. Open Biol 2016; 5:rsob.150067. [PMID: 26289801 PMCID: PMC4554919 DOI: 10.1098/rsob.150067] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Mechanisms that regulate partitioning of the endoplasmic reticulum (ER) during cell division are largely unknown. Previous studies have mostly addressed ER partitioning in cultured cells, which may not recapitulate physiological processes that are critical in developing, intact tissues. We have addressed this by analysing ER partitioning in asymmetrically dividing stem cells, in which precise segregation of cellular components is essential for proper development and tissue architecture. We show that in Drosophila neural stem cells, called neuroblasts, the ER asymmetrically partitioned to centrosomes early in mitosis. This correlated closely with the asymmetric nucleation of astral microtubules (MTs) by centrosomes, suggesting that astral MT association may be required for ER partitioning by centrosomes. Consistent with this, the ER also associated with astral MTs in meiotic Drosophila spermatocytes and during syncytial embryonic divisions. Disruption of centrosomes in each of these cell types led to improper ER partitioning, demonstrating the critical role for centrosomes and associated astral MTs in this process. Importantly, we show that the ER also associated with astral MTs in cultured human cells, suggesting that this centrosome/astral MT-based partitioning mechanism is conserved across animal species.
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Affiliation(s)
- Jeremy T Smyth
- Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA Department of Anatomy, Physiology, and Genetics, Uniformed Services University of the Health Sciences-F. Edward Hébert School of Medicine, Bethesda, MD 20814, USA
| | - Todd A Schoborg
- Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Zane J Bergman
- Department of Biology, San Francisco State University, 1600 Holloway Avenue, San Francisco, CA 94132, USA
| | - Blake Riggs
- Department of Biology, San Francisco State University, 1600 Holloway Avenue, San Francisco, CA 94132, USA
| | - Nasser M Rusan
- Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
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47
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Zheng Y, Mennella V, Marks S, Wildonger J, Elnagdi E, Agard D, Megraw TL. The Seckel syndrome and centrosomal protein Ninein localizes asymmetrically to stem cell centrosomes but is not required for normal development, behavior, or DNA damage response in Drosophila. Mol Biol Cell 2016; 27:1740-52. [PMID: 27053665 PMCID: PMC4884065 DOI: 10.1091/mbc.e15-09-0655] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Accepted: 03/28/2016] [Indexed: 12/21/2022] Open
Abstract
Ninein associates with the microtubule regulator γ-tubulin, regulates microtubule assembly, and localizes to centrosomes and noncentrosomal microtubule-organizing centers in Drosophila. Ninein localizes to stem cell centrosomes asymmetrically, with a bias for the daughter centrosome. Remarkably, Ninein is dispensable for development, fertility, or viability. Ninein (Nin) is a centrosomal protein whose gene is mutated in Seckel syndrome (SCKL, MIM 210600), an inherited recessive disease that results in primordial dwarfism, cognitive deficiencies, and increased sensitivity to genotoxic stress. Nin regulates neural stem cell self-renewal, interkinetic nuclear migration, and microtubule assembly in mammals. Nin is evolutionarily conserved, yet its role in cell division and development has not been investigated in a model organism. Here we characterize the single Nin orthologue in Drosophila. Drosophila Nin localizes to the periphery of the centrosome but not at centriolar structures as in mammals. However, Nin shares the property of its mammalian orthologue of promoting microtubule assembly. In neural and germline stem cells, Nin localizes asymmetrically to the younger (daughter) centrosome, yet it is not required for the asymmetric division of stem cells. In wing epithelia and muscle, Nin localizes to noncentrosomal microtubule-organizing centers. Surprisingly, loss of nin expression from a nin mutant does not significantly affect embryonic and brain development, fertility, or locomotor performance of mutant flies or their survival upon exposure to DNA-damaging agents. Although it is not essential, our data suggest that Nin plays a supportive role in centrosomal and extracentrosomal microtubule organization and asymmetric stem cell division.
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Affiliation(s)
- Yiming Zheng
- Department of Biomedical Sciences, Florida State University, Tallahassee, FL 32306-4300
| | - Vito Mennella
- Department of Biochemistry, University of Toronto, Toronto, M5G 0A4, Canada Cell Biology Program, The Hospital for Sick Children, Toronto, M5G 1X8, Canada
| | - Steven Marks
- Department of Biomedical Sciences, Florida State University, Tallahassee, FL 32306-4300
| | - Jill Wildonger
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706
| | - Esraa Elnagdi
- Department of Biochemistry, University of Toronto, Toronto, M5G 0A4, Canada Cell Biology Program, The Hospital for Sick Children, Toronto, M5G 1X8, Canada
| | - David Agard
- The Howard Hughes Medical Institute and Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94143-2240
| | - Timothy L Megraw
- Department of Biomedical Sciences, Florida State University, Tallahassee, FL 32306-4300
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48
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Applewhite DA, Davis CA, Griffis ER, Quintero OA. Imaging of the Cytoskeleton Using Live and Fixed Drosophila Tissue Culture Cells. Methods Mol Biol 2016; 1365:83-97. [PMID: 26498780 DOI: 10.1007/978-1-4939-3124-8_4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
Abstract
In recent years, the convergence of multiple technologies and experimental approaches has led to the expanded use of cultured Drosophila cells as a model system. Their ease of culture and maintenance, susceptibility to RNA interference, and imaging characteristics have led to extensive use in both traditional experimental approaches as well as high-throughput RNAi screens. Here we describe Drosophila S2 cell culture and preparation for live-cell and fixed-cell fluorescence microscopy and scanning electron microscopy.
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Affiliation(s)
| | - Christine A Davis
- Department of Biology, University of Richmond, B-214 Gottwald science Center, 28 Westhampton Way, Richmond, VA, 23173, USA
| | - Eric R Griffis
- Wellcome Trust Centre for Gene Regulation and Expression, College of Life Sciences, University of Dundee, Dundee, UK
| | - Omar A Quintero
- Department of Biology, University of Richmond, B-214 Gottwald science Center, 28 Westhampton Way, Richmond, VA, 23173, USA.
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49
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Abstract
Microtubules are cytoskeletal filaments that are intrinsically polarized, with two structurally and functionally distinct ends, the plus end and the minus end. Over the last decade, numerous studies have shown that microtubule plus-end dynamics play an important role in many vital cellular processes and are controlled by numerous factors, such as microtubule plus-end-tracking proteins (+TIPs). In contrast, the cellular machinery that controls the behavior and organization of microtubule minus ends remains one of the least well-understood facets of the microtubule cytoskeleton. The recent characterization of the CAMSAP/Patronin/Nezha family members as specific 'minus-end-targeting proteins' ('-TIPs') has provided important new insights into the mechanisms governing minus-end dynamics. Here, we review the current state of knowledge on how microtubule minus ends are controlled and how minus-end regulators contribute to non-centrosomal microtubule organization and function during cell division, migration and differentiation.
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50
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Abstract
It has become clear that the role of centrosomes extends well beyond that of important microtubule organizers. There is increasing evidence that they also function as coordination centres in eukaryotic cells, at which specific cytoplasmic proteins interact at high concentrations and important cell decisions are made. Accordingly, hundreds of proteins are concentrated at centrosomes, including cell cycle regulators, checkpoint proteins and signalling molecules. Nevertheless, several observations have raised the question of whether centrosomes are essential for many cell processes. Recent findings have shed light on the functions of centrosomes in animal cells and on the molecular mechanisms of centrosome assembly, in particular during mitosis. These advances should ultimately allow the in vitro reconstitution of functional centrosomes from their component proteins to unlock the secrets of these enigmatic organelles.
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