1
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Okada H, Chen X, Wang K, Marquardt J, Bi E. Bni5 tethers myosin-II to septins to enhance retrograde actin flow and the robustness of cytokinesis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.07.566094. [PMID: 37986946 PMCID: PMC10659389 DOI: 10.1101/2023.11.07.566094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
The collaboration between septins and myosin-II in driving processes outside of cytokinesis remains largely uncharted. Here, we demonstrate that Bni5 in the budding yeast S. cerevisiae interacts with myosin-II, septin filaments, and the septin-associated kinase Elm1 via distinct domains at its N- and C-termini, thereby tethering the mobile myosin-II to the stable septin hourglass at the division site from bud emergence to the onset of cytokinesis. The septin and Elm1-binding domains, together with a central disordered region, of Bni5 control timely remodeling of the septin hourglass into a double ring, enabling the actomyosin ring constriction. The Bni5-tethered myosin-II enhances retrograde actin cable flow, which contributes to the asymmetric inheritance of mitochondria-associated protein aggregates during cell division, and also strengthens cytokinesis against various perturbations. Thus, we have established a biochemical pathway involving septin-Bni5-myosin-II interactions at the division site, which can inform mechanistic understanding of the role of myosin-II in other retrograde flow systems. Summary Okada et al. have determined the molecular mechanism underlying the Bni5 interactions with septins and myosin-II at the cell division site and uncovered its roles in promoting retrograde actin flow and the robustness of cytokinesis in budding yeast.
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2
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Sharma A, Martoliya Y, Mondal AK. BEM2, a RHO GTPase Activating Protein That Regulates Morphogenesis in S. cerevisiae, Is a Downstream Effector of Fungicidal Action of Fludioxonil. J Fungi (Basel) 2022; 8:jof8070754. [PMID: 35887509 PMCID: PMC9316689 DOI: 10.3390/jof8070754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 06/11/2022] [Accepted: 06/12/2022] [Indexed: 12/02/2022] Open
Abstract
Fludioxonil belongs to the phenylpyrrole group of fungicides with a broad antifungal spectrum that has been widely used in agricultural practices for the past thirty years. Although fludioxonil is known to exert its fungicidal action through group III hybrid histidine kinases, the downstream effector of its cytotoxicity is poorly understood. In this study, we utilized a S. cerevisiae model to decipher the cytotoxic effect of fludioxonil. Through genome wide transposon mutagenesis, we have identified Bem2, a Rho GTPase activating protein, which is involved in this process. The deletion of BEM2 resulted in fludioxonil resistance. Our results showed that both the GAP and morphogenesis checkpoint activities of Bem2 were important for this. We also provided the genetic evidence that the role of Bem2 in the cell wall integrity (CWI) pathway and cell cycle regulation could contribute to the fludioxonil resistance phenotype.
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Affiliation(s)
- Anupam Sharma
- CSIR-Institute of Microbial Technology, Sector 39A, Chandigarh 160036, India;
| | - Yogita Martoliya
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India;
| | - Alok K. Mondal
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India;
- Correspondence: ; Tel.: +91-1126704514
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3
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Guan Y, Wang D, Lin X, Li X, Lv C, Wang D, Zhang L. Unveiling a Novel Role of Cdc42 in Pyruvate Metabolism Pathway to Mediate Insecticidal Activity of Beauveria bassiana. J Fungi (Basel) 2022; 8:jof8040394. [PMID: 35448625 PMCID: PMC9031566 DOI: 10.3390/jof8040394] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 04/10/2022] [Accepted: 04/11/2022] [Indexed: 02/04/2023] Open
Abstract
The small GTPase Cdc42 acts as a molecular switch essential for cell cycles and polar growth in model yeast, but has not been explored in Beaurveria bassiana, an insect-pathogenic fungus serving as a main source of fungal formulations against arthropod pests. Here, we show the indispensability of Cdc42 for fungal insecticidal activity. Deletion of cdc42 in B. bassiana resulted in a great loss of virulence to Galleria mellonella, a model insect, via normal cuticle infection as well as defects in conidial germination, radial growth, aerial conidiation, and conidial tolerance to heat and UVB irradiation. The deleted mutant’s hyphae formed fewer or more septa and produced unicellular blastospores with disturbed cell cycles under submerged-culture conditions. Transcriptomic analysis revealed differential expression of 746 genes and dysregulation of pyruvate metabolism and related pathways, which were validated by marked changes in intracellular pyruvate content, ATP content, related enzyme activities, and in extracellular beauvericin content and Pr1 protease activity vital for fungal virulence. These findings uncover a novel role for Cdc42 in the pathways of pyruvate metabolism and the pyruvate-involved tricarboxylic acid cycle (TCA cycle) and a linkage of the novel role with its indispensability for the biological control potential of B. bassiana against arthropod pests.
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Affiliation(s)
- Yi Guan
- Fujian Key Laboratory of Marine Enzyme Engineering, College of Biological Science and Engineering, Fuzhou University, Fuzhou 350116, China; (D.W.); (X.L.); (X.L.); (C.L.)
- Correspondence: (Y.G.); (L.Z.)
| | - Donghuang Wang
- Fujian Key Laboratory of Marine Enzyme Engineering, College of Biological Science and Engineering, Fuzhou University, Fuzhou 350116, China; (D.W.); (X.L.); (X.L.); (C.L.)
| | - Xiaofeng Lin
- Fujian Key Laboratory of Marine Enzyme Engineering, College of Biological Science and Engineering, Fuzhou University, Fuzhou 350116, China; (D.W.); (X.L.); (X.L.); (C.L.)
| | - Xin Li
- Fujian Key Laboratory of Marine Enzyme Engineering, College of Biological Science and Engineering, Fuzhou University, Fuzhou 350116, China; (D.W.); (X.L.); (X.L.); (C.L.)
| | - Chao Lv
- Fujian Key Laboratory of Marine Enzyme Engineering, College of Biological Science and Engineering, Fuzhou University, Fuzhou 350116, China; (D.W.); (X.L.); (X.L.); (C.L.)
| | - Dingyi Wang
- School of Geographical Sciences, Fujian Normal University, Fuzhou 350007, China;
| | - Longbin Zhang
- Fujian Key Laboratory of Marine Enzyme Engineering, College of Biological Science and Engineering, Fuzhou University, Fuzhou 350116, China; (D.W.); (X.L.); (X.L.); (C.L.)
- Correspondence: (Y.G.); (L.Z.)
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4
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Marquardt J, Chen X, Bi E. Septin Assembly and Remodeling at the Cell Division Site During the Cell Cycle. Front Cell Dev Biol 2021; 9:793920. [PMID: 34901034 PMCID: PMC8656427 DOI: 10.3389/fcell.2021.793920] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 11/08/2021] [Indexed: 11/17/2022] Open
Abstract
The septin family of proteins can assemble into filaments that further organize into different higher order structures to perform a variety of different functions in different cell types and organisms. In the budding yeast Saccharomyces cerevisiae, the septins localize to the presumptive bud site as a cortical ring prior to bud emergence, expand into an hourglass at the bud neck (cell division site) during bud growth, and finally “split” into a double ring sandwiching the cell division machinery during cytokinesis. While much work has been done to understand the functions and molecular makeups of these structures, the mechanisms underlying the transitions from one structure to another have largely remained elusive. Recent studies involving advanced imaging and in vitro reconstitution have begun to reveal the vast complexity involved in the regulation of these structural transitions, which defines the focus of discussion in this mini-review.
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Affiliation(s)
- Joseph Marquardt
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Xi Chen
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Erfei Bi
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
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5
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Hassell DS, Steingesser MG, Denney AS, Johnson CR, McMurray MA. Chemical rescue of mutant proteins in living Saccharomyces cerevisiae cells by naturally occurring small molecules. G3-GENES GENOMES GENETICS 2021; 11:6323229. [PMID: 34544143 PMCID: PMC8496222 DOI: 10.1093/g3journal/jkab252] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 06/29/2021] [Indexed: 11/14/2022]
Abstract
Intracellular proteins function in a complex milieu wherein small molecules influence protein folding and act as essential cofactors for enzymatic reactions. Thus protein function depends not only on amino acid sequence but also on the concentrations of such molecules, which are subject to wide variation between organisms, metabolic states, and environmental conditions. We previously found evidence that exogenous guanidine reverses the phenotypes of specific budding yeast septin mutants by binding to a WT septin at the former site of an Arg side chain that was lost during fungal evolution. Here, we used a combination of targeted and unbiased approaches to look for other cases of "chemical rescue" by naturally occurring small molecules. We report in vivo rescue of hundreds of Saccharomyces cerevisiae mutants representing a variety of genes, including likely examples of Arg or Lys side chain replacement by the guanidinium ion. Failed rescue of targeted mutants highlight features required for rescue, as well as key differences between the in vitro and in vivo environments. Some non-Arg mutants rescued by guanidine likely result from "off-target" effects on specific cellular processes in WT cells. Molecules isosteric to guanidine and known to influence protein folding had a range of effects, from essentially none for urea, to rescue of a few mutants by DMSO. Strikingly, the osmolyte trimethylamine-N-oxide rescued ∼20% of the mutants we tested, likely reflecting combinations of direct and indirect effects on mutant protein function. Our findings illustrate the potential of natural small molecules as therapeutic interventions and drivers of evolution.
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Affiliation(s)
- Daniel S Hassell
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Marc G Steingesser
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Ashley S Denney
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Courtney R Johnson
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Michael A McMurray
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
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6
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Marquardt J, Yao LL, Okada H, Svitkina T, Bi E. The LKB1-like Kinase Elm1 Controls Septin Hourglass Assembly and Stability by Regulating Filament Pairing. Curr Biol 2020; 30:2386-2394.e4. [PMID: 32386534 PMCID: PMC7314651 DOI: 10.1016/j.cub.2020.04.035] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 03/20/2020] [Accepted: 04/16/2020] [Indexed: 01/22/2023]
Abstract
Septins form rod-shaped hetero-oligomeric complexes that assemble into filaments and other higher-order structures, such as rings or hourglasses, at the cell division site in fungal and animal cells [1-4] to carry out a wide range of functions, including cytokinesis and cell morphogenesis. However, the architecture of septin higher-order assemblies and their control mechanisms, including regulation by conserved kinases [5, 6], remain largely unknown. In the budding yeast Saccharomyces cerevisiae, the five mitotic septins (Cdc3, Cdc10, Cdc11, Cdc12, and Shs1) localize to the bud neck and form an hourglass before cytokinesis that acts as a scaffold for proteins involved in multiple processes as well as a membrane-diffusible barrier between the mother and developing bud [7-9]. The hourglass is remodeled into a double ring that sandwiches the actomyosin ring at the onset of cytokinesis [10-13]. How septins are assembled into a highly ordered hourglass structure at the division site [13] is largely unexplored. Here we show that the LKB1-like kinase Elm1, which has been implicated in septin organization [14], cell morphogenesis [15], and mitotic exit [16, 17], specifically associates with the septin hourglass during the cell cycle and controls hourglass assembly and stability, especially for the daughter half, by regulating filament pairing and the functionality of its substrate, the septin-binding protein Bni5. This study illustrates how a protein kinase regulates septin architecture at the filament level and suggests that filament pairing is a highly regulated process during septin assembly and remodeling in vivo.
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Affiliation(s)
- Joseph Marquardt
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6058, USA
| | - Lin-Lin Yao
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6058, USA; Group of Cell Motility and Muscle Contraction, State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Hiroki Okada
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6058, USA
| | - Tatyana Svitkina
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Erfei Bi
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6058, USA.
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7
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Prabhakar A, Chow J, Siegel AJ, Cullen PJ. Regulation of intrinsic polarity establishment by a differentiation-type MAPK pathway in S. cerevisiae. J Cell Sci 2020; 133:jcs241513. [PMID: 32079658 PMCID: PMC7174846 DOI: 10.1242/jcs.241513] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Accepted: 02/12/2020] [Indexed: 01/15/2023] Open
Abstract
All cells establish and maintain an axis of polarity that is critical for cell shape and progression through the cell cycle. A well-studied example of polarity establishment is bud emergence in the yeast Saccharomyces cerevisiae, which is controlled by the Rho GTPase Cdc42p. The prevailing view of bud emergence does not account for regulation by extrinsic cues. Here, we show that the filamentous growth mitogen activated protein kinase (fMAPK) pathway regulates bud emergence under nutrient-limiting conditions. The fMAPK pathway regulated the expression of polarity targets including the gene encoding a direct effector of Cdc42p, Gic2p. The fMAPK pathway also stimulated GTP-Cdc42p levels, which is a critical determinant of polarity establishment. The fMAPK pathway activity was spatially restricted to bud sites and active during the period of the cell cycle leading up to bud emergence. Time-lapse fluorescence microscopy showed that the fMAPK pathway stimulated the rate of bud emergence during filamentous growth. Unregulated activation of the fMAPK pathway induced multiple rounds of symmetry breaking inside the growing bud. Collectively, our findings identify a new regulatory aspect of bud emergence that sensitizes this essential cellular process to external cues.
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Affiliation(s)
- Aditi Prabhakar
- Department of Biological Sciences, University at Buffalo, Buffalo, NY 14260-1300, USA
| | - Jacky Chow
- Department of Biological Sciences, University at Buffalo, Buffalo, NY 14260-1300, USA
| | - Alan J Siegel
- Department of Biological Sciences, University at Buffalo, Buffalo, NY 14260-1300, USA
| | - Paul J Cullen
- Department of Biological Sciences, University at Buffalo, Buffalo, NY 14260-1300, USA
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8
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Chen X, Wang K, Svitkina T, Bi E. Critical Roles of a RhoGEF-Anillin Module in Septin Architectural Remodeling during Cytokinesis. Curr Biol 2020; 30:1477-1490.e3. [PMID: 32197082 DOI: 10.1016/j.cub.2020.02.023] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 12/23/2019] [Accepted: 02/10/2020] [Indexed: 12/24/2022]
Abstract
How septin architecture is remodeled from an hourglass to a double ring during cytokinesis in fungal and animal cells remains unknown. Here, we show that during the hourglass-to-double-ring transition in budding yeast, septins acquire a "zonal architecture" in which paired septin filaments that are organized along the mother-bud axis associate with circumferential single septin filaments, the Rho guanine-nucleotide-exchange factor (RhoGEF) Bud3, and the anillin-like protein Bud4 exclusively at the outer zones and with myosin-II filaments in the middle zone. Deletion of Bud3 or its Bud4-interacting domain, but not its RhoGEF domain, leads to a complete loss of the single filaments, whereas deletion of Bud4 or its Bud3-interacting domain destabilizes the transitional hourglass, especially at the mother side, with partial loss of both filament types. Deletion of Bud3 and Bud4 together further weakens the transitional structure and abolishes the double ring formation while causing no obvious defect in actomyosin ring constriction. This and further analyses suggest that Bud3 stabilizes the single filaments, whereas Bud4 strengthens the interaction between the paired and single filaments at the outer zones of the transitional hourglass, as well as in the double ring. This study reveals a striking zonal architecture for the transitional hourglass that pre-patterns two cytokinetic structures-a septin double ring and an actomyosin ring-and also defines the essential roles of a RhoGEF-anillin module in septin architectural remodeling during cytokinesis at the filament level.
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Affiliation(s)
- Xi Chen
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6058, USA
| | - Kangji Wang
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6058, USA
| | - Tatyana Svitkina
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Erfei Bi
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6058, USA.
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9
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Yeast as a Model to Understand Actin-Mediated Cellular Functions in Mammals-Illustrated with Four Actin Cytoskeleton Proteins. Cells 2020; 9:cells9030672. [PMID: 32164332 PMCID: PMC7140605 DOI: 10.3390/cells9030672] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 03/05/2020] [Accepted: 03/05/2020] [Indexed: 12/31/2022] Open
Abstract
The budding yeast Saccharomyces cerevisiae has an actin cytoskeleton that comprises a set of protein components analogous to those found in the actin cytoskeletons of higher eukaryotes. Furthermore, the actin cytoskeletons of S. cerevisiae and of higher eukaryotes have some similar physiological roles. The genetic tractability of budding yeast and the availability of a stable haploid cell type facilitates the application of molecular genetic approaches to assign functions to the various actin cytoskeleton components. This has provided information that is in general complementary to that provided by studies of the equivalent proteins of higher eukaryotes and hence has enabled a more complete view of the role of these proteins. Several human functional homologues of yeast actin effectors are implicated in diseases. A better understanding of the molecular mechanisms underpinning the functions of these proteins is critical to develop improved therapeutic strategies. In this article we chose as examples four evolutionarily conserved proteins that associate with the actin cytoskeleton: (1) yeast Hof1p/mammalian PSTPIP1, (2) yeast Rvs167p/mammalian BIN1, (3) yeast eEF1A/eEF1A1 and eEF1A2 and (4) yeast Yih1p/mammalian IMPACT. We compare the knowledge on the functions of these actin cytoskeleton-associated proteins that has arisen from studies of their homologues in yeast with information that has been obtained from in vivo studies using live animals or in vitro studies using cultured animal cell lines.
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10
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Kubo K, Okada H, Shimamoto T, Kimori Y, Mizunuma M, Bi E, Ohnuki S, Ohya Y. Implications of maintenance of mother-bud neck size in diverse vital processes of Saccharomyces cerevisiae. Curr Genet 2019; 65:253-267. [PMID: 30066140 DOI: 10.1007/s00294-018-0872-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 07/17/2018] [Accepted: 07/25/2018] [Indexed: 11/25/2022]
Abstract
The mother-bud neck is defined as the boundary between the mother cell and bud in budding microorganisms, wherein sequential morphological events occur throughout the cell cycle. This study was designed to quantitatively investigate the morphology of the mother-bud neck in budding yeast Saccharomyces cerevisiae. Observation of yeast cells with time-lapse microscopy revealed an increase of mother-bud neck size through the cell cycle. After screening of yeast non-essential gene-deletion mutants with the image processing software CalMorph, we comprehensively identified 274 mutants with broader necks during S/G2 phase. Among these yeasts, we extensively analyzed 19 representative deletion mutants with defects in genes annotated to six gene ontology terms (polarisome, actin reorganization, endosomal tethering complex, carboxy-terminal domain protein kinase complex, DNA replication, and maintenance of DNA trinucleotide repeats). The representative broad-necked mutants exhibited calcofluor white sensitivity, suggesting defects in their cell walls. Correlation analysis indicated that maintenance of mother-bud neck size is important for cellular processes such as cell growth, system robustness, and replicative lifespan. We conclude that neck-size maintenance in budding yeast is regulated by numerous genes and has several aspects that are physiologically significant.
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Affiliation(s)
- Karen Kubo
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo, Kashiwa, Chiba, 277-8562, Japan
| | - Hiroki Okada
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104-6058, USA
| | - Takuya Shimamoto
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo, Kashiwa, Chiba, 277-8562, Japan
| | - Yoshitaka Kimori
- Department of Imaging Science, Center for Novel Science Initiatives, National Institutes of Natural Sciences, Okazaki, 444-8787, Japan
- Department of Management and Information Sciences, Faculty of Environmental and Information Sciences, Fukui University of Technology, Gakuen, Fukui City, Fukui, 910-8505, Japan
| | - Masaki Mizunuma
- Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, 739-8530, Japan
| | - Erfei Bi
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104-6058, USA
| | - Shinsuke Ohnuki
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo, Kashiwa, Chiba, 277-8562, Japan
| | - Yoshikazu Ohya
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo, Kashiwa, Chiba, 277-8562, Japan.
- AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory (OPERANDO-OIL), National Institute of Advanced Industrial Science and Technology (AIST), Kashiwa, Chiba, 277-8565, Japan.
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11
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Allard CAH, Decker F, Weiner OD, Toettcher JE, Graziano BR. A size-invariant bud-duration timer enables robustness in yeast cell size control. PLoS One 2018; 13:e0209301. [PMID: 30576342 PMCID: PMC6303054 DOI: 10.1371/journal.pone.0209301] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 11/28/2018] [Indexed: 12/20/2022] Open
Abstract
Cell populations across nearly all forms of life generally maintain a characteristic cell type-dependent size, but how size control is achieved has been a long-standing question. The G1/S boundary of the cell cycle serves as a major point of size control, and mechanisms operating here restrict passage of cells to Start if they are too small. In contrast, it is less clear how size is regulated post-Start, during S/G2/M. To gain further insight into post-Start size control, we prepared budding yeast that can be reversibly blocked from bud initiation. While blocked, cells continue to grow isotropically, increasing their volume by more than an order of magnitude over unperturbed cells. Upon release from their block, giant mothers reenter the cell cycle and their progeny rapidly return to the original unperturbed size. We found this behavior to be consistent with a size-invariant 'timer' specifying the duration of S/G2/M. These results indicate that yeast use at least two distinct mechanisms at different cell cycle phases to ensure size homeostasis.
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Affiliation(s)
- Corey A. H. Allard
- Marine Biological Laboratory, Woods Hole, MA, United States of America
- Dept. of Biochemistry and Cell Biology, The Geisel School of Medicine at Dartmouth, Hanover, NH, United States of America
| | - Franziska Decker
- Marine Biological Laboratory, Woods Hole, MA, United States of America
- Max Planck Institute for the Physics of Complex Systems, Max Planck Institute of Molecular Cell Biology and Genetics, Center for Systems Biology Dresden, Dresden, Germany
| | - Orion D. Weiner
- Marine Biological Laboratory, Woods Hole, MA, United States of America
- Cardiovascular Research Institute and Dept. of Biochemistry and Biophysics, UC San Francisco, San Francisco, United States of America
| | - Jared E. Toettcher
- Marine Biological Laboratory, Woods Hole, MA, United States of America
- Department of Molecular Biology, Princeton University, Princeton, NJ, United States of America
| | - Brian R. Graziano
- Marine Biological Laboratory, Woods Hole, MA, United States of America
- Cardiovascular Research Institute and Dept. of Biochemistry and Biophysics, UC San Francisco, San Francisco, United States of America
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12
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Huang CY, Wang YY, Chen YL, Chen MF, Chiang HS, Kuo PL, Lin YH. CDC42 Negatively Regulates Testis-Specific SEPT12 Polymerization. Int J Mol Sci 2018; 19:ijms19092627. [PMID: 30189608 PMCID: PMC6163814 DOI: 10.3390/ijms19092627] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 08/31/2018] [Accepted: 09/03/2018] [Indexed: 01/04/2023] Open
Abstract
Septin (SEPT) genes encode well-preserved polymerizing GTP-binding cytoskeletal proteins. The cellular functions of SEPTs consist of mitosis, cytoskeletal remodeling, cell polarity, and vesicle trafficking through interactions with various types of cytoskeletons. We discovered that mutated SEPTIN12 in different codons resulted in teratozoospermia or oligozoospermia. In mouse models with a defective Septin12 allele, sperm morphology was abnormal, sperm count decreased, and sperms were immotile. However, the regulators of SEPT12 are completely unknown. Some studies have indicated that CDC42 negatively regulates the polymerization of SEPT2/6/7 complexes in mammalian cell lines. In this study, we investigated whether CDC42 modulates SEPT12 polymerization and is involved in the terminal differentiation of male germ cells. First, through scanning electron microscopy analysis, we determined that the loss of Septin12 caused defective sperm heads. This indicated that Septin12 is critical for the formation of sperm heads. Second, CDC42 and SEPT12 were similarly localized in the perinuclear regions of the manchette at the head of elongating spermatids, neck region of elongated spermatids, and midpiece of mature spermatozoa. Third, wild-type CDC42 and CDC42Q61L (a constitutive-acting-mutant) substantially repressed SEPT12 polymerization, but CDC42T17N (a dominant-negative-acting mutant) did not, as evident through ectopic expression analysis. We concluded that CDC42 negatively regulates SEPT12 polymerization and is involved in terminal structure formation of sperm heads.
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Affiliation(s)
- Chia-Yen Huang
- Department of Biological Science and Technology, National Chiao Tung University, Hsinchu 300, Taiwan.
- Gynecologic Cancer Center, Department of Obstetrics and Gynecology, Cathay General Hospital, Taipei 106, Taiwan.
- School of Medicine, Fu Jen Catholic University, New Taipei City 242, Taiwan.
| | - Ya-Yun Wang
- Department of Chemistry, Fu Jen Catholic University, New Taipei City 242, Taiwan.
| | - Ying-Liang Chen
- Department of Environmental Engineering, National Cheng Kung University, Tainan 701, Taiwan.
| | - Mei-Feng Chen
- Bone and Joint Research Center, Chang Gung Memorial Hospital, Taoyuan 333, Taiwan.
| | - Han-Sun Chiang
- Graduate Institute of Biomedical and Pharmaceutical Science, Fu Jen Catholic University, New Taipei City 242, Taiwan.
| | - Pao-Lin Kuo
- Department of Obstetrics & Gynecology, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan.
| | - Ying-Hung Lin
- Graduate Institute of Biomedical and Pharmaceutical Science, Fu Jen Catholic University, New Taipei City 242, Taiwan.
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13
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Marquardt J, Chen X, Bi E. Architecture, remodeling, and functions of the septin cytoskeleton. Cytoskeleton (Hoboken) 2018; 76:7-14. [PMID: 29979831 DOI: 10.1002/cm.21475] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 06/05/2018] [Accepted: 06/22/2018] [Indexed: 01/22/2023]
Abstract
The septin family of proteins has fascinated cell biologists for decades due to the elaborate architecture they adopt in different eukaryotic cells. Whether they exist as rings, collars, or gauzes in different cell types and at different times in the cell cycle illustrates a complex series of regulation in structure. While the organization of different septin structures at the cortex of different cell types during the cell cycle has been described to various degrees, the exact structure and regulation at the filament level are still largely unknown. Recent advances in fluorescent and electron microscopy, as well as work in septin biochemistry, have allowed new insights into the aspects of septin architecture, remodeling, and function in many cell types. This mini-review highlights many of the recent findings with an emphasis on the budding yeast model.
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Affiliation(s)
- Joseph Marquardt
- Department of Cell and Developmental Biology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Xi Chen
- Department of Cell and Developmental Biology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Erfei Bi
- Department of Cell and Developmental Biology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
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14
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Boubakar L, Falk J, Ducuing H, Thoinet K, Reynaud F, Derrington E, Castellani V. Molecular Memory of Morphologies by Septins during Neuron Generation Allows Early Polarity Inheritance. Neuron 2017; 95:834-851.e5. [DOI: 10.1016/j.neuron.2017.07.027] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Revised: 05/23/2017] [Accepted: 07/24/2017] [Indexed: 01/22/2023]
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15
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Abstract
Cytokinesis is essential for the survival of all organisms. It requires concerted functions of cell signaling, force production, exocytosis, and extracellular matrix remodeling. Due to the conservation in core components and mechanisms between fungal and animal cells, the budding yeast Saccharomyces cerevisiae has served as an attractive model for studying this fundamental process. In this review, we discuss the mechanics and regulation of distinct events of cytokinesis in budding yeast, including the assembly, constriction, and disassembly of the actomyosin ring, septum formation, abscission, and their spatiotemporal coordination. We also highlight the key concepts and questions that are common to animal and fungal cytokinesis.
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Affiliation(s)
- Yogini P Bhavsar-Jog
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Erfei Bi
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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16
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Juanes MA, Piatti S. The final cut: cell polarity meets cytokinesis at the bud neck in S. cerevisiae. Cell Mol Life Sci 2016; 73:3115-36. [PMID: 27085703 PMCID: PMC4951512 DOI: 10.1007/s00018-016-2220-3] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Revised: 03/22/2016] [Accepted: 04/05/2016] [Indexed: 02/07/2023]
Abstract
Cell division is a fundamental but complex process that gives rise to two daughter cells. It includes an ordered set of events, altogether called "the cell cycle", that culminate with cytokinesis, the final stage of mitosis leading to the physical separation of the two daughter cells. Symmetric cell division equally partitions cellular components between the two daughter cells, which are therefore identical to one another and often share the same fate. In many cases, however, cell division is asymmetrical and generates two daughter cells that differ in specific protein inheritance, cell size, or developmental potential. The budding yeast Saccharomyces cerevisiae has proven to be an excellent system to investigate the molecular mechanisms governing asymmetric cell division and cytokinesis. Budding yeast is highly polarized during the cell cycle and divides asymmetrically, producing two cells with distinct sizes and fates. Many components of the machinery establishing cell polarization during budding are relocalized to the division site (i.e., the bud neck) for cytokinesis. In this review we recapitulate how budding yeast cells undergo polarized processes at the bud neck for cell division.
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Affiliation(s)
- Maria Angeles Juanes
- Centre de Recherche en Biologie Cellulaire de Montpellier, 1919 Route de Mende, 34293, Montpellier, France
- Brandeis University, 415 South Street, Waltham, MA, 02454, USA
| | - Simonetta Piatti
- Centre de Recherche en Biologie Cellulaire de Montpellier, 1919 Route de Mende, 34293, Montpellier, France.
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17
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Rippert D, Heinisch JJ. Investigation of the role of four mitotic septins and chitin synthase 2 for cytokinesis in Kluyveromyces lactis. Fungal Genet Biol 2016; 94:69-78. [PMID: 27422440 DOI: 10.1016/j.fgb.2016.07.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2016] [Revised: 07/08/2016] [Accepted: 07/12/2016] [Indexed: 11/15/2022]
Abstract
Septins are key components of the cell division machinery from yeast to humans. The model yeast Saccharomyces cerevisiae has five mitotic septins, Cdc3, Cdc10, Cdc11, Cdc12, and Shs1. Here we characterized the five orthologs from the genetically less-redundant milk yeast Kluyveromyces lactis. We found that except for KlSHS1 all septin genes are essential. Klshs1 deletions displayed temperature-sensitive growth and morphological defects. Heterologous complementation analyses revealed that all five K. lactis genes encode functional orthologs of their S. cerevisiae counterparts. Fluorophore-tagged versions of the K. lactis septins localized to a ring at the incipient bud site and split into two separate rings at the bud neck later in cytokinesis. One of the key proteins recruited to the bud neck by septins in S. cerevisiae is the chitin synthase Chs2, which synthesizes the primary septum. KlCHS2 was found to be essential and deletions showed cytokinetic defects upon spore germination. KlChs2-GFP also localized to the bud neck and to punctate structures in K. lactis. We conclude that cytokinesis in K. lactis is similar to S. cerevisiae and chimeric septin complexes are fully functional in both yeasts. In contrast to some S. cerevisiae strains, KlChs2 and KlCdc10 were found to be essential.
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Affiliation(s)
- Dorthe Rippert
- Universität Osnabrück, Fachbereich Biologie/Chemie, AG Genetik, 49076 Osnabrück, Germany
| | - Jürgen J Heinisch
- Universität Osnabrück, Fachbereich Biologie/Chemie, AG Genetik, 49076 Osnabrück, Germany.
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18
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Au Yong JY, Wang YM, Wang Y. The Nim1 kinase Gin4 has distinct domains crucial for septin assembly, phospholipid binding and mitotic exit. J Cell Sci 2016; 129:2744-56. [PMID: 27231094 PMCID: PMC4958294 DOI: 10.1242/jcs.183160] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Accepted: 05/20/2016] [Indexed: 12/29/2022] Open
Abstract
In fungi, the Nim1 protein kinases, such as Gin4, are important regulators of multiple cell cycle events, including the G2–M transition, septin assembly, polarized growth and cytokinesis. Compelling evidence has linked some key functions of Gin4 with the large C-terminal non-kinase region which, however, is poorly defined. By systematically dissecting and functionally characterizing the non-kinase region of Gin4 in the human fungal pathogen Candida albicans, we report the identification of three new domains with distinct functions: a lipid-binding domain (LBD), a septin-binding domain (SBD) and a nucleolus-associating domain (NAD). The LBD and SBD are indispensable for the function of Gin4, and they alone could sufficiently restore septin ring assembly in GIN4-null mutants. The NAD localizes to the periphery of the nucleolus and physically associates with Cdc14, the ultimate effector of the mitotic exit network. Gin4 mutants that lack the NAD are defective in spindle orientation and exit mitosis prematurely. Furthermore, we show that Gin4 is a substrate of Cdc14. These findings provide novel insights into the roles and mechanisms of Nim1 kinases in the regulation of some crucial cell cycle events. Summary: Systematic dissection of the Gin4 kinase in the human pathogenic fungus Candida albicans uncovers three new functional domains that interact with distinct cellular components.
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Affiliation(s)
- Jie Ying Au Yong
- Institute of Molecular and Cell Biology, Agency for Science, Technology, and Research, Singapore 138673
| | - Yan-Ming Wang
- Institute of Molecular and Cell Biology, Agency for Science, Technology, and Research, Singapore 138673
| | - Yue Wang
- Institute of Molecular and Cell Biology, Agency for Science, Technology, and Research, Singapore 138673 Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597
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19
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Ong K, Svitkina T, Bi E. Visualization of in vivo septin ultrastructures by platinum replica electron microscopy. Methods Cell Biol 2016; 136:73-97. [PMID: 27473904 PMCID: PMC5497467 DOI: 10.1016/bs.mcb.2016.03.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
Septins are cytoskeletal proteins involved in diverse biological processes including cytokinesis, cell morphogenesis, motility, and ciliogenesis. Septins form various filamentous structures in vitro and in vivo, but the higher-order architecture of septin structures in vivo remains poorly defined. The best understood system in this respect is the budding yeast Saccharomyces cerevisiae, where septins form a ring structure that undergoes multiple stages of remodeling during the cell cycle. In this chapter, we describe a method for visualizing supramolecular septin structures in yeast at high spatial resolution using platinum replica electron microscopy. This approach can be applied to further understand the regulation of assembly and remodeling of septin higher-order structures, as well as the relationship between septin architecture and function.
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Affiliation(s)
- K. Ong
- University of Pennsylvania, Philadelphia, PA, United States
| | - T. Svitkina
- University of Pennsylvania, Philadelphia, PA, United States
| | - E. Bi
- University of Pennsylvania, Philadelphia, PA, United States
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20
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McMurray MA. Assays for genetic dissection of septin filament assembly in yeast, from de novo folding through polymerization. Methods Cell Biol 2016; 136:99-116. [PMID: 27473905 DOI: 10.1016/bs.mcb.2016.03.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Abstract
In Saccharomyces cerevisiae, septin mutations have severe effects on colony-forming ability, particularly at high temperatures, allowing the full variety of genetic tools available in this model organism to be applied to the study of septin biology. Although many details of septin function remain unknown, one can exploit a small number of easily scored phenotypes-proliferation capacity, cell morphology, septin localization, and septin ring integrity-as sensitive readouts of properly assembled septin filaments. Accordingly, this chapter focuses on genetic approaches targeted toward understanding the molecular mechanisms of de novo septin folding, heterooligomerization, and polymerization into filaments. The same general methods can be used to interrogate septin function, although interpretation of results can be more complicated. As genetic-based methodologies are technically simple but particularly dependent on interpretation, here I focus on the logic underlying the most common interpretations of results using septin mutants.
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Affiliation(s)
- M A McMurray
- University of Colorado Anschutz Medical Campus, Aurora, CO, United States.
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21
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Abstract
Cytokinesis is the final process in the cell cycle that physically divides one cell into two. In budding yeast, cytokinesis is driven by a contractile actomyosin ring (AMR) and the simultaneous formation of a primary septum, which serves as template for cell wall deposition. AMR assembly, constriction, primary septum formation and cell wall deposition are successive processes and tightly coupled to cell cycle progression to ensure the correct distribution of genetic material and cell organelles among the two rising cells prior to cell division. The role of the AMR in cytokinesis and the molecular mechanisms that drive AMR constriction and septation are the focus of current research. This review summarizes the recent progresses in our understanding of how budding yeast cells orchestrate the multitude of molecular mechanisms that control AMR driven cytokinesis in a spatio-temporal manner to achieve an error free cell division.
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22
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Merlini L, Bolognesi A, Juanes MA, Vandermoere F, Courtellemont T, Pascolutti R, Séveno M, Barral Y, Piatti S. Rho1- and Pkc1-dependent phosphorylation of the F-BAR protein Syp1 contributes to septin ring assembly. Mol Biol Cell 2015; 26:3245-62. [PMID: 26179915 PMCID: PMC4569315 DOI: 10.1091/mbc.e15-06-0366] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Accepted: 07/10/2015] [Indexed: 12/20/2022] Open
Abstract
Septins often form filaments and rings at the neck of cellular appendages. Assembly of these structures must be coordinated with membrane remodeling. In budding yeast, the Rho1 GTPase and its effector, Pkc1, play a role in septin ring stabilization during budding at least partly through phosphorylation of the bud neck–associated F-BAR protein Syp1. In many cell types, septins assemble into filaments and rings at the neck of cellular appendages and/or at the cleavage furrow to help compartmentalize the plasma membrane and support cytokinesis. How septin ring assembly is coordinated with membrane remodeling and controlled by mechanical stress at these sites is unclear. Through a genetic screen, we uncovered an unanticipated link between the conserved Rho1 GTPase and its effector protein kinase C (Pkc1) with septin ring stability in yeast. Both Rho1 and Pkc1 stabilize the septin ring, at least partly through phosphorylation of the membrane-associated F-BAR protein Syp1, which colocalizes asymmetrically with the septin ring at the bud neck. Syp1 is displaced from the bud neck upon Pkc1-dependent phosphorylation at two serines, thereby affecting the rigidity of the new-forming septin ring. We propose that Rho1 and Pkc1 coordinate septin ring assembly with membrane and cell wall remodeling partly by controlling Syp1 residence at the bud neck.
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Affiliation(s)
- Laura Merlini
- Centre de Recherche en Biochimie Macromoléculaire, 34293 Montpellier, France
| | | | | | - Franck Vandermoere
- Functional Proteomic Platform, Institut de Génomique Fonctionnelle, 34094 Montpellier, France
| | | | - Roberta Pascolutti
- Centre de Recherche en Biochimie Macromoléculaire, 34293 Montpellier, France
| | - Martial Séveno
- Functional Proteomic Platform, Institut de Génomique Fonctionnelle, 34094 Montpellier, France
| | - Yves Barral
- Institute of Biochemistry, ETH Zurich, 8093 Zurich, Switzerland
| | - Simonetta Piatti
- Centre de Recherche en Biochimie Macromoléculaire, 34293 Montpellier, France
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23
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Calderón-Noreña DM, González-Novo A, Orellana-Muñoz S, Gutiérrez-Escribano P, Arnáiz-Pita Y, Dueñas-Santero E, Suárez MB, Bougnoux ME, del Rey F, Sherlock G, d’Enfert C, Correa-Bordes J, de Aldana CRV. A single nucleotide polymorphism uncovers a novel function for the transcription factor Ace2 during Candida albicans hyphal development. PLoS Genet 2015; 11:e1005152. [PMID: 25875512 PMCID: PMC4398349 DOI: 10.1371/journal.pgen.1005152] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 03/17/2015] [Indexed: 01/10/2023] Open
Abstract
Candida albicans is a major invasive fungal pathogen in humans. An important virulence factor is its ability to switch between the yeast and hyphal forms, and these filamentous forms are important in tissue penetration and invasion. A common feature for filamentous growth is the ability to inhibit cell separation after cytokinesis, although it is poorly understood how this process is regulated developmentally. In C. albicans, the formation of filaments during hyphal growth requires changes in septin ring dynamics. In this work, we studied the functional relationship between septins and the transcription factor Ace2, which controls the expression of enzymes that catalyze septum degradation. We found that alternative translation initiation produces two Ace2 isoforms. While full-length Ace2, Ace2L, influences septin dynamics in a transcription-independent manner in hyphal cells but not in yeast cells, the use of methionine-55 as the initiation codon gives rise to Ace2S, which functions as the nuclear transcription factor required for the expression of cell separation genes. Genetic evidence indicates that Ace2L influences the incorporation of the Sep7 septin to hyphal septin rings in order to avoid inappropriate activation of cell separation during filamentous growth. Interestingly, a natural single nucleotide polymorphism (SNP) present in the C. albicans WO-1 background and other C. albicans commensal and clinical isolates generates a stop codon in the ninth codon of Ace2L that mimics the phenotype of cells lacking Ace2L. Finally, we report that Ace2L and Ace2S interact with the NDR kinase Cbk1 and that impairing activity of this kinase results in a defect in septin dynamics similar to that of hyphal cells lacking Ace2L. Together, our findings identify Ace2L and the NDR kinase Cbk1 as new elements of the signaling system that modify septin ring dynamics in hyphae to allow cell-chain formation, a feature that appears to have evolved in specific C. albicans lineages.
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Affiliation(s)
- Diana M. Calderón-Noreña
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas (CSIC)/Universidad de Salamanca (USAL), Salamanca, Spain
| | - Alberto González-Novo
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas (CSIC)/Universidad de Salamanca (USAL), Salamanca, Spain
| | - Sara Orellana-Muñoz
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas (CSIC)/Universidad de Salamanca (USAL), Salamanca, Spain
| | - Pilar Gutiérrez-Escribano
- Departamento de Ciencias Biomédicas, Facultad de Ciencias, Universidad de Extremadura, Badajoz, Spain
| | - Yolanda Arnáiz-Pita
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas (CSIC)/Universidad de Salamanca (USAL), Salamanca, Spain
| | - Encarnación Dueñas-Santero
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas (CSIC)/Universidad de Salamanca (USAL), Salamanca, Spain
| | - M. Belén Suárez
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas (CSIC)/Universidad de Salamanca (USAL), Salamanca, Spain
| | - Marie-Elisabeth Bougnoux
- Institut Pasteur, Unité Biologie et Pathogénicité Fongiques, Département Mycologie, Paris, France
- INRA, USC2019, Paris, France
| | - Francisco del Rey
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas (CSIC)/Universidad de Salamanca (USAL), Salamanca, Spain
| | - Gavin Sherlock
- Department of Genetics, Stanford University, Stanford, California, United States of America
| | - Christophe d’Enfert
- Institut Pasteur, Unité Biologie et Pathogénicité Fongiques, Département Mycologie, Paris, France
- INRA, USC2019, Paris, France
| | - Jaime Correa-Bordes
- Departamento de Ciencias Biomédicas, Facultad de Ciencias, Universidad de Extremadura, Badajoz, Spain
| | - Carlos R. Vázquez de Aldana
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas (CSIC)/Universidad de Salamanca (USAL), Salamanca, Spain
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24
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Zou W, Yan J, Zhao N, Niu S, Huang X. A novel role for the alcohol sensitive ring/PHD finger protein Asr1p in regulating cell cycle mediated by septin-dependent assembly in yeast. Biochem Biophys Res Commun 2015; 458:208-13. [PMID: 25646695 DOI: 10.1016/j.bbrc.2015.01.113] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Accepted: 01/24/2015] [Indexed: 10/25/2022]
Abstract
Septin is a conserved eukaryotic family of GTP-binding filament-forming proteins with functions in cytokinesis and other processes. It has been suggested that the dynamic assembly of septin, including the processes from septin initially localizing to the presumptive bud site to the septin collar finally splitting into two cells, coordinates closely with the checkpoint response of cell cycle. Here, we discovered that over-expression of Alcohol sensitive Ring/PHD finger 1 protein (Asr1p) in Saccharomyces cerevisiae triggered the Swe1p-dependent cell cycle checkpoint for a G2/M transition delay, and this G2/M transition delay was caused by the septin defect. Since it was shown that Asr1p affected actin dynamics through the interaction with Crn1p and crn1 should be epistatic to asr1 in the regulation of actin, the gene knockout of crn1 in the Asr1p over-expression strain restored the defects in septin and cell cycle along with the disordered actin dynamics. Our investigation further showed that the disturbed septin assembly caused by abnormal Asr1p lead to the abnormal localization of the checkpoint proteins such as Gla4/PAK and Cdc5/Polo, and finally triggered the Swe1p-dependent G2/M transition arrest. Additionally, the Ring finger/PHD domains of Asr1p were illustrated to be required but not sufficient for its role in septin. Taken together, our current data suggested a close relationship in the assembly between septin and actin cytoskeleton, which also partially explained how actin cytoskeleton participated in the regulation of the checkpoint of G2/M.
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Affiliation(s)
- Wei Zou
- Laboratory for Conservation and Utilization of Bio-Resources, and Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, PR China
| | - Jinyuan Yan
- Laboratory for Conservation and Utilization of Bio-Resources, and Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, PR China
| | - Ninghui Zhao
- Department of Neurosurgery, The Second Affiliated Hospital of Kunmin Medical College, Kunming 650101, PR China
| | - Shanzhuang Niu
- Laboratory for Conservation and Utilization of Bio-Resources, and Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, PR China
| | - Xiaowei Huang
- Laboratory for Conservation and Utilization of Bio-Resources, and Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, PR China.
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25
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Higuchi-Sanabria R, Pernice WMA, Vevea JD, Alessi Wolken DM, Boldogh IR, Pon LA. Role of asymmetric cell division in lifespan control in Saccharomyces cerevisiae. FEMS Yeast Res 2014; 14:1133-46. [PMID: 25263578 PMCID: PMC4270926 DOI: 10.1111/1567-1364.12216] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Revised: 09/22/2014] [Accepted: 09/22/2014] [Indexed: 11/29/2022] Open
Abstract
Aging determinants are asymmetrically distributed during cell division in S. cerevisiae, which leads to production of an immaculate, age-free daughter cell. During this process, damaged components are sequestered and retained in the mother cell, and higher functioning organelles and rejuvenating factors are transported to and/or enriched in the bud. Here, we will describe the key quality control mechanisms in budding yeast that contribute to asymmetric cell division of aging determinants including mitochondria, endoplasmic reticulum (ER), vacuoles, extrachromosomal rDNA circles (ERCs), and protein aggregates.
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Affiliation(s)
- Ryo Higuchi-Sanabria
- Department of Pathology and Cell Biology, College of Physicians and Surgeons, Columbia University, New York, NY, USA
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26
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Role of Candida albicans Tem1 in mitotic exit and cytokinesis. Fungal Genet Biol 2014; 69:84-95. [PMID: 24973462 DOI: 10.1016/j.fgb.2014.06.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Revised: 06/12/2014] [Accepted: 06/17/2014] [Indexed: 11/20/2022]
Abstract
Candida albicans demonstrates three main growth morphologies: yeast, pseudohyphal and true hyphal forms. Cell separation is distinct in these morphological forms and the process of separation is closely linked to the completion of mitosis and cytokinesis. In Saccharomyces cerevisiae the small GTPase Tem1 is known to initiate the mitotic exit network, a signalling pathway involved in signalling the end of mitosis and initiating cytokinesis and cell separation. Here we have characterised the role of Tem1 in C. albicans, and demonstrate that it is essential for mitotic exit and cytokinesis, and that this essential function is signalled through the kinase Cdc15. Cells depleted of Tem1 displayed highly polarised growth but ultimately failed to both complete cytokinesis and re-enter the cell cycle following nuclear division. Consistent with its role in activating the mitotic exit network Tem1 localises to spindle pole bodies in a cell cycle-dependent manner. Ultimately, the mitotic exit network in C. albicans appears to co-ordinate the sequential processes of mitotic exit, cytokinesis and cell separation.
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27
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Cassani C, Raspelli E, Chiroli E, Fraschini R. Vhs2 is a novel regulator of septin dynamics in budding yeast. Cell Cycle 2014; 13:1590-601. [PMID: 24646733 DOI: 10.4161/cc.28561] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
In budding yeast, septins are assembled into structures that undergo dramatic changes during the cell cycle. The molecular mechanisms that drive these remodelings are not fully uncovered. In this study, we describe a characterization of Vhs2, a nonessential protein that revealed to be a new player in septin dynamics. In particular, we report that Vhs2 is important to maintain the stability of the double septin ring structure until telophase. In addition, we show that Vhs2 undergoes multiple phosphorylations during the cell cycle, being phosphorylated during S phase until nuclear division and dephosphorylated just before cell division. Importantly we report that cyclin-dependent protein kinase Cdk1 and protein phosphatase Cdc14 control these Vhs2 post-translational modifications. These results reveal that Vhs2 is a novel Cdc14 substrate that is involved in the control of septin organization.
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Affiliation(s)
- Corinne Cassani
- Università degli Studi di Milano-Bicocca; Dipartimento di Biotecnologie e Bioscienze; Milano, Italy
| | - Erica Raspelli
- Università degli Studi di Milano-Bicocca; Dipartimento di Biotecnologie e Bioscienze; Milano, Italy
| | - Elena Chiroli
- IFOM - Istituto FIRC di Oncologia Molecolare; Milano, Italy
| | - Roberta Fraschini
- Università degli Studi di Milano-Bicocca; Dipartimento di Biotecnologie e Bioscienze; Milano, Italy
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28
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Martin SG, Arkowitz RA. Cell polarization in budding and fission yeasts. FEMS Microbiol Rev 2014; 38:228-53. [DOI: 10.1111/1574-6976.12055] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Revised: 11/13/2013] [Accepted: 12/03/2013] [Indexed: 11/30/2022] Open
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29
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Sept6 is required for ciliogenesis in Kupffer's vesicle, the pronephros, and the neural tube during early embryonic development. Mol Cell Biol 2014; 34:1310-21. [PMID: 24469395 DOI: 10.1128/mcb.01409-13] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Septins are conserved filament-forming GTP-binding proteins that act as cellular scaffolds or diffusion barriers in a number of cellular processes. However, the role of septins in vertebrate development remains relatively obscure. Here, we show that zebrafish septin 6 (sept6) is first expressed in the notochord and then in nearly all of the ciliary organs, including Kupffer's vesicle (KV), the pronephros, eye, olfactory bulb, and neural tube. Knockdown of sept6 in zebrafish embryos results in reduced numbers and length of cilia in KV. Consequently, cilium-related functions, such as the left-right patterning of internal organs and nodal/spaw signaling, are compromised. Knockdown of sept6 also results in aberrant cilium formation in the pronephros and neural tube, leading to cilium-related defects in pronephros development and Sonic hedgehog (Shh) signaling. We further demonstrate that SEPT6 associates with acetylated α-tubulin in vivo and localizes along the axoneme in the cilia of zebrafish pronephric duct cells as well as cultured ZF4 cells. Our study reveals a novel role of sept6 in ciliogenesis during early embryonic development in zebrafish.
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30
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Wolken DMA, McInnes J, Pon LA. Aim44p regulates phosphorylation of Hof1p to promote contractile ring closure during cytokinesis in budding yeast. Mol Biol Cell 2014; 25:753-62. [PMID: 24451263 PMCID: PMC3952846 DOI: 10.1091/mbc.e13-06-0317] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Aim44p undergoes septin-dependent localization to the actomyosin ring and regulates contractile ring closure and the abundance, phosphorylation, and dynamics of Hof1p, a regulator of actomyosin ring closure. It also interacts directly with Hof1p. Thus Aim44p is a novel regulator of contractile ring closure in budding yeast. Whereas actomyosin and septin ring organization and function in cytokinesis are thoroughly described, little is known regarding the mechanisms by which the actomyosin ring interacts with septins and associated proteins to coordinate cell division. Here we show that the protein product of YPL158C, Aim44p, undergoes septin-dependent recruitment to the site of cell division. Aim44p colocalizes with Myo1p, the type II myosin of the contractile ring, throughout most of the cell cycle. The Aim44p ring does not contract when the actomyosin ring closes. Instead, it forms a double ring that associates with septin rings on mother and daughter cells after cell separation. Deletion of AIM44 results in defects in contractile ring closure. Aim44p coimmunoprecipitates with Hof1p, a conserved F-BAR protein that binds both septins and type II myosins and promotes contractile ring closure. Deletion of AIM44 results in a delay in Hof1p phosphorylation and altered Hof1p localization. Finally, overexpression of Dbf2p, a kinase that phosphorylates Hof1p and is required for relocalization of Hof1p from septin rings to the contractile ring and for Hof1p-triggered contractile ring closure, rescues the cytokinesis defect observed in aim44∆ cells. Our studies reveal a novel role for Aim44p in regulating contractile ring closure through effects on Hof1p.
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Affiliation(s)
- Dana M Alessi Wolken
- Department of Pathology and Cell Biology, Columbia University, New York, NY 10027 School of Engineering and Science, Jacobs University Bremen, 28759 Bremen, Germany
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31
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Naylor SG, Morgan DO. Cdk1-dependent phosphorylation of Iqg1 governs actomyosin ring assembly prior to cytokinesis. J Cell Sci 2014; 127:1128-37. [PMID: 24413167 DOI: 10.1242/jcs.144097] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Contraction of the actomyosin ring (AMR) provides the centripetal force that drives cytokinesis. In budding yeast (Saccharomyces cerevisiae), assembly and contraction of the AMR is coordinated with membrane deposition and septum formation at the bud neck. A central player in this process is Iqg1, which promotes recruitment of actin to the myosin ring and links AMR assembly with that of septum-forming components. We observed early actin recruitment in response to inhibition of cyclin-dependent kinase 1 (Cdk1) activity, and we find that the Cdk1-dependent phosphorylation state of Iqg1 is a determining factor in the timing of bud neck localization of both Iqg1 and actin, with both proteins accumulating prematurely in cells expressing nonphosphorylatable Iqg1 mutants. We also identified the primary septum regulator Hof1 as a binding partner of Iqg1, providing a regulatory link between the septation and contractile pathways that cooperate to complete cytokinesis.
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Affiliation(s)
- Stephen G Naylor
- Departments of Physiology and Biochemistry & Biophysics, University of California, San Francisco, CA 94158, USA
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32
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Atkins BD, Yoshida S, Saito K, Wu CF, Lew DJ, Pellman D. Inhibition of Cdc42 during mitotic exit is required for cytokinesis. ACTA ACUST UNITED AC 2013; 202:231-40. [PMID: 23878274 PMCID: PMC3718968 DOI: 10.1083/jcb.201301090] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
A decrease in Cdc42 activation during mitotic exit is necessary to allow localization of key cytokinesis regulators and proper septum formation. The role of Cdc42 and its regulation during cytokinesis is not well understood. Using biochemical and imaging approaches in budding yeast, we demonstrate that Cdc42 activation peaks during the G1/S transition and during anaphase but drops during mitotic exit and cytokinesis. Cdc5/Polo kinase is an important upstream cell cycle regulator that suppresses Cdc42 activity. Failure to down-regulate Cdc42 during mitotic exit impairs the normal localization of key cytokinesis regulators—Iqg1 and Inn1—at the division site, and results in an abnormal septum. The effects of Cdc42 hyperactivation are largely mediated by the Cdc42 effector p21-activated kinase Ste20. Inhibition of Cdc42 and related Rho guanosine triphosphatases may be a general feature of cytokinesis in eukaryotes.
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Affiliation(s)
- Benjamin D Atkins
- Department of Pediatric Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA 02115, USA
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33
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Garnica DP, Upadhyaya NM, Dodds PN, Rathjen JP. Strategies for Wheat Stripe Rust Pathogenicity Identified by Transcriptome Sequencing. PLoS One 2013; 8:e67150. [PMID: 23840606 PMCID: PMC3694141 DOI: 10.1371/journal.pone.0067150] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2013] [Accepted: 05/14/2013] [Indexed: 12/31/2022] Open
Abstract
Stripe rust caused by the fungus Puccinia striiformis f.sp. tritici (Pst) is a major constraint to wheat production worldwide. The molecular events that underlie Pst pathogenicity are largely unknown. Like all rusts, Pst creates a specialized cellular structure within host cells called the haustorium to obtain nutrients from wheat, and to secrete pathogenicity factors called effector proteins. We purified Pst haustoria and used next-generation sequencing platforms to assemble the haustorial transcriptome as well as the transcriptome of germinated spores. 12,282 transcripts were assembled from 454-pyrosequencing data and used as reference for digital gene expression analysis to compare the germinated uredinospores and haustoria transcriptomes based on Illumina RNAseq data. More than 400 genes encoding secreted proteins which constitute candidate effectors were identified from the haustorial transcriptome, with two thirds of these up-regulated in this tissue compared to germinated spores. RT-PCR analysis confirmed the expression patterns of 94 effector candidates. The analysis also revealed that spores rely mainly on stored energy reserves for growth and development, while haustoria take up host nutrients for massive energy production for biosynthetic pathways and the ultimate production of spores. Together, these studies substantially increase our knowledge of potential Pst effectors and provide new insights into the pathogenic strategies of this important organism.
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Affiliation(s)
- Diana P. Garnica
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory, Australia
| | - Narayana M. Upadhyaya
- Division of Plant Industry, Commonwealth Scientific and Industrial Research Organisation (CSIRO), Canberra, Australian Capital Territory, Australia
| | - Peter N. Dodds
- Division of Plant Industry, Commonwealth Scientific and Industrial Research Organisation (CSIRO), Canberra, Australian Capital Territory, Australia
| | - John P. Rathjen
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory, Australia
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34
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Yamazaki T, Owari S, Ota S, Sumiya N, Yamamoto M, Watanabe K, Nagumo T, Miyamura S, Kawano S. Localization and evolution of septins in algae. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2013; 74:605-614. [PMID: 23398289 DOI: 10.1111/tpj.12147] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Revised: 01/31/2013] [Accepted: 02/05/2013] [Indexed: 06/01/2023]
Abstract
Septins are a group of GTP-binding proteins that are multi-functional, with a well-known role in cytokinesis in animals and fungi. Although the functions of septins have been thoroughly studied in opisthokonts (fungi and animals), the function and evolution of plant/algal septins are not as well characterized. Here we describe septin localization and expression in the green algae Nannochloris bacillaris and Marvania geminata. The present data suggest that septins localize at the division site when cytokinesis occurs. In addition, we show that septin homologs may be found only in green algae, but not in other major plant lineages, such as land plants, red algae and glaucophytes. We also found other septin homolog-possessing organisms among the diatoms, Rhizaria and cryptomonad/haptophyte lineages. Our study reveals the potential role of algal septins in cytokinesis and/or cell elongation, and confirms that septin genes appear to have been lost in the Plantae lineage, except in some green algae.
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Affiliation(s)
- Tomokazu Yamazaki
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8562, Japan
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35
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Walker LA, Lenardon MD, Preechasuth K, Munro CA, Gow NAR. Cell wall stress induces alternative fungal cytokinesis and septation strategies. J Cell Sci 2013; 126:2668-77. [PMID: 23606739 DOI: 10.1242/jcs.118885] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
In fungi, as with all walled organisms, cytokinesis followed by septation marks the end of the cell cycle and is essential for cell division and viability. For yeasts, the septal cross-wall comprises a ring and primary septal plate composed of chitin, and a secondary septum thickened with β(1,3)-glucan. In the human pathogen Candida albicans, chitin synthase enzyme Chs1 builds the primary septum that is surrounded by a chitin ring made by Chs3. Here we show that the lethal phenotype induced by repression of CHS1 was abrogated by stress-induced synthesis of alternative and novel septal types synthesized by other chitin synthase enzymes that have never before been implicated in septation. Chs2 and Chs8 formed a functional salvage septum, even in the absence of both Chs1 and Chs3. A second type of salvage septum formed by Chs2 in combination with Chs3 or Chs8 was proximally offset in the mother-bud neck. Chs3 alone or in combination with Chs8 formed a greatly thickened third type of salvage septum. Therefore, cell wall stress induced alternative forms of septation that rescued cell division in the absence of Chs1, demonstrating that fungi have previously unsuspected redundant strategies to enable septation and cell division to be maintained, even under potentially lethal environmental conditions.
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Affiliation(s)
- Louise A Walker
- Aberdeen Fungal Group, School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
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36
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Wloka C, Vallen EA, Thé L, Fang X, Oh Y, Bi E. Immobile myosin-II plays a scaffolding role during cytokinesis in budding yeast. J Cell Biol 2013; 200:271-86. [PMID: 23358243 PMCID: PMC3563683 DOI: 10.1083/jcb.201208030] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Accepted: 12/28/2012] [Indexed: 01/13/2023] Open
Abstract
Core components of cytokinesis are conserved from yeast to human, but how these components are assembled into a robust machine that drives cytokinesis remains poorly understood. In this paper, we show by fluorescence recovery after photobleaching analysis that Myo1, the sole myosin-II in budding yeast, was mobile at the division site before anaphase and became immobilized shortly before cytokinesis. This immobility was independent of actin filaments or the motor domain of Myo1 but required a small region in the Myo1 tail that is thought to be involved in higher-order assembly. As expected, proteins involved in actin ring assembly (tropomyosin and formin) and membrane trafficking (myosin-V and exocyst) were dynamic during cytokinesis. Strikingly, proteins involved in septum formation (the chitin synthase Chs2) and/or its coordination with the actomyosin ring (essential light chain, IQGAP, F-BAR, etc.) displayed Myo1-dependent immobility during cytokinesis, suggesting that Myo1 plays a scaffolding role in the assembly of a cytokinesis machine.
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Affiliation(s)
- Carsten Wloka
- Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104
- Institut für Biologie, Freie Universität Berlin, 14195 Berlin, Germany
| | | | - Lydia Thé
- Department of Biology, Swarthmore College, Swarthmore, PA 19081
| | - Xiaodong Fang
- Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104
| | - Younghoon Oh
- Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104
| | - Erfei Bi
- Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104
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37
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Tartakoff AM, Aylyarov I, Jaiswal P. Septin-containing barriers control the differential inheritance of cytoplasmic elements. Cell Rep 2012; 3:223-36. [PMID: 23273916 DOI: 10.1016/j.celrep.2012.11.022] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2012] [Revised: 09/27/2012] [Accepted: 11/27/2012] [Indexed: 01/12/2023] Open
Abstract
Fusion of haploid cells of Saccharomyces cerevisiae generates zygotes. We observe that the zygote midzone includes a septin annulus and differentially affects redistribution of supramolecular complexes and organelles. Redistribution across the midzone of supramolecular complexes (polysomes and Sup35p-GFP [PSI+]) is unexpectedly delayed relative to soluble proteins; however, in [psi-] × [PSI+] crosses, all buds eventually receive Sup35p-GFP [PSI+]. Encounter between parental mitochondria is further delayed until septins relocate to the bud site, where they are required for repolarization of the actin cytoskeleton. This delay allows rationalization of the longstanding observation that terminal zygotic buds preferentially inherit a single mitochondrial genotype. The rate of redistribution of complexes and organelles determines whether their inheritance will be uniform.
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Affiliation(s)
- Alan Michael Tartakoff
- Pathology Department and Cell Biology Program, Case Western Reserve University, 2103 Cornell Road, Cleveland, OH 44106, USA.
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38
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Wloka C, Bi E. Mechanisms of cytokinesis in budding yeast. Cytoskeleton (Hoboken) 2012; 69:710-26. [DOI: 10.1002/cm.21046] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2012] [Accepted: 06/15/2012] [Indexed: 01/22/2023]
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39
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Bi E, Park HO. Cell polarization and cytokinesis in budding yeast. Genetics 2012; 191:347-87. [PMID: 22701052 PMCID: PMC3374305 DOI: 10.1534/genetics.111.132886] [Citation(s) in RCA: 217] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2011] [Accepted: 11/04/2011] [Indexed: 12/26/2022] Open
Abstract
Asymmetric cell division, which includes cell polarization and cytokinesis, is essential for generating cell diversity during development. The budding yeast Saccharomyces cerevisiae reproduces by asymmetric cell division, and has thus served as an attractive model for unraveling the general principles of eukaryotic cell polarization and cytokinesis. Polarity development requires G-protein signaling, cytoskeletal polarization, and exocytosis, whereas cytokinesis requires concerted actions of a contractile actomyosin ring and targeted membrane deposition. In this chapter, we discuss the mechanics and spatial control of polarity development and cytokinesis, emphasizing the key concepts, mechanisms, and emerging questions in the field.
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Affiliation(s)
- Erfei Bi
- Department of Cell and Developmental Biology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-6058, USA.
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40
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Epstein S, Castillon GA, Qin Y, Riezman H. An essential function of sphingolipids in yeast cell division. Mol Microbiol 2012; 84:1018-32. [DOI: 10.1111/j.1365-2958.2012.08087.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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41
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A simple, versatile method for GFP-based super-resolution microscopy via nanobodies. Nat Methods 2012; 9:582-4. [DOI: 10.1038/nmeth.1991] [Citation(s) in RCA: 445] [Impact Index Per Article: 37.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Accepted: 03/28/2012] [Indexed: 12/11/2022]
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42
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The septin AspB in Aspergillus nidulans forms bars and filaments and plays roles in growth emergence and conidiation. EUKARYOTIC CELL 2012; 11:311-23. [PMID: 22247265 DOI: 10.1128/ec.05164-11] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
In yeast, septins form rings at the mother-bud neck and function as diffusion barriers. In animals, septins form filaments that can colocalize with other cytoskeletal elements. In the filamentous fungus Aspergillus nidulans there are five septin genes, aspA (an ortholog of Saccharomyces cerevisiae CDC11), aspB (an ortholog of S. cerevisiae CDC3), aspC (an ortholog of S. cerevisiae CDC12), aspD (an ortholog of S. cerevisiae CDC10), and aspE (found only in filamentous fungi). The aspB gene was previously reported to be the most highly expressed Aspergillus nidulans septin and to be essential. Using improved gene targeting techniques, we found that deletion of aspB is not lethal but results in delayed septation, increased emergence of germ tubes and branches, and greatly reduced conidiation. We also found that AspB-green fluorescent protein (GFP) localizes as rings and collars at septa, branches, and emerging layers of the conidiophore and as bars and filaments in conidia and hyphae. Bars are found in dormant and isotropically expanding conidia and in subapical nongrowing regions of hyphae and display fast movements. Filaments form as the germ tube emerges, localize to hyphal and branch tips, and display slower movements. All visible AspB-GFP structures are retained in ΔaspD and lost in ΔaspA and ΔaspC strains. Interestingly, in the ΔaspE mutant, AspB-GFP rings, bars, and filaments are visible in early growth, but AspB-GFP rods and filaments disappear after septum formation. AspE orthologs are only found in filamentous fungi, suggesting that this class of septins might be required for stability of septin bars and filaments in highly polar cells.
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43
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Wloka C, Nishihama R, Onishi M, Oh Y, Hanna J, Pringle JR, Krauss M, Bi E. Evidence that a septin diffusion barrier is dispensable for cytokinesis in budding yeast. Biol Chem 2011; 392:813-29. [PMID: 21824009 DOI: 10.1515/bc.2011.083] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Septins are essential for cytokinesis in Saccharomyces cerevisiae, but their precise roles remain elusive. Currently, it is thought that before cytokinesis, the hourglass-shaped septin structure at the mother-bud neck acts as a scaffold for assembly of the actomyosin ring (AMR) and other cytokinesis factors. At the onset of cytokinesis, the septin hourglass splits to form a double ring that sandwiches the AMR and may function as diffusion barriers to restrict diffusible cytokinesis factors to the division site. Here, we show that in cells lacking the septin Cdc10 or the septin-associated protein Bud4, the septins form a ring-like structure at the mother-bud neck that fails to re-arrange into a double ring early in cytokinesis. Strikingly, AMR assembly and constriction, the localization of membrane-trafficking and extracellular-matrix-remodeling factors, cytokinesis, and cell-wall-septum formation all occur efficiently in cdc10Δ and bud4Δ mutants. Thus, diffusion barriers formed by the septin double ring do not appear to be critical for S. cerevisiae cytokinesis. However, an AMR mutation and a septin mutation have synergistic effects on cytokinesis and the localization of cytokinesis proteins, suggesting that tethering to the AMR and a septin diffusion barrier may function redundantly to localize proteins to the division site.
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Affiliation(s)
- Carsten Wloka
- Department of Cell and Developmental Biology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104-6058, USA
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44
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Septin structure and function in yeast and beyond. Trends Cell Biol 2010; 21:141-8. [PMID: 21177106 DOI: 10.1016/j.tcb.2010.11.006] [Citation(s) in RCA: 162] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2010] [Revised: 11/04/2010] [Accepted: 11/15/2010] [Indexed: 12/30/2022]
Abstract
Septins are conserved GTP-binding proteins that assemble into hetero-oligomeric complexes and higher-order structures such as filaments, rings, hourglasses or gauzes. Septins are usually associated with a discrete region of the plasma membrane and function as a cell scaffold or diffusion barrier to effect cytokinesis, cell polarity, and many other functions. Recent structural studies of septin complexes have provided mechanistic insights into septin filament assembly, but key questions concerning the assembly, dynamics, and function of different septin structures remain to be answered.
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45
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Heng YW, Koh CG. Actin cytoskeleton dynamics and the cell division cycle. Int J Biochem Cell Biol 2010; 42:1622-33. [PMID: 20412868 DOI: 10.1016/j.biocel.2010.04.007] [Citation(s) in RCA: 193] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2010] [Revised: 04/12/2010] [Accepted: 04/14/2010] [Indexed: 11/29/2022]
Abstract
The network of actin filaments is one of the crucial cytoskeletal structures contributing to the morphological framework of a cell and which participates in the dynamic regulation of cellular functions. In adherent cell types, cells adhere to the substratum during interphase and spread to assume their characteristic shape supported by the actin cytoskeleton. This actin cytoskeleton is reorganized during mitosis to form rounded cells with increased cortical rigidity. The actin cytoskeleton is re-established after mitosis, allowing cells to regain their extended shape and attachment to the substratum. The modulation of such drastic changes in cell shape in coordination with cell cycle progression suggests a tight regulatory interaction between cytoskeleton signalling, cell-cell/cell-matrix adhesions and mitotic events. Here, we review the contribution of the actin cytoskeleton to cell cycle progression with an emphasis on the effectors responsible for the regulation of the actin cytoskeleton and integration of their activities with the cell cycle machinery.
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Affiliation(s)
- Yi-Wen Heng
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
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46
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Larson JR, Kozubowski L, Tatchell K. Changes in Bni4 localization induced by cell stress in Saccharomyces cerevisiae. J Cell Sci 2010; 123:1050-9. [PMID: 20197406 DOI: 10.1242/jcs.066258] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Septin complexes at the bud neck in Saccharomyces cerevisiae serve as a scaffold for proteins involved in signaling, cell cycle control, and cell wall synthesis. Many of these bind asymmetrically, associating with either the mother- or daughter-side of the neck. Septin structures are inherently apolar so the basis for the asymmetric binding remains unknown. Bni4, a regulatory subunit of yeast protein phosphatase type 1, Glc7, binds to the outside of the septin ring prior to bud formation and remains restricted to the mother-side of the bud neck after bud emergence. Bni4 is responsible for targeting Glc7 to the mother-side of the bud neck for proper deposition of the chitin ring. We show here that Bni4 localizes symmetrically, as two distinct rings on both sides of the bud neck following energy depletion or activation of cell cycle checkpoints. Our data indicate that loss of Bni4 asymmetry can occur via at least two different mechanisms. Furthermore, we show that Bni4 has a Swe1-dependent role in regulating the cell morphogenesis checkpoint in response to hydroxyurea, which suggests that the change in localization of Bni4 following checkpoint activation may help stabilize the cell cycle regulator Swe1 during cell cycle arrest.
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Affiliation(s)
- Jennifer R Larson
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, Shreveport, LA 71130, USA
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47
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Ballou ER, Nichols CB, Miglia KJ, Kozubowski L, Alspaugh JA. Two CDC42 paralogues modulate Cryptococcus neoformans thermotolerance and morphogenesis under host physiological conditions. Mol Microbiol 2009; 75:763-80. [PMID: 20025659 DOI: 10.1111/j.1365-2958.2009.07019.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The precise regulation of morphogenesis is a key mechanism by which cells respond to a variety of stresses, including those encountered by microbial pathogens in the host. The polarity protein Cdc42 regulates cellular morphogenesis throughout eukaryotes, and we explore the role of Cdc42 proteins in the host survival of the human fungal pathogen Cryptococcus neoformans. Uniquely, C. neoformans has two functional Cdc42 paralogues, Cdc42 and Cdc420. Here we investigate the contribution of each paralogue to resistance to host stress. In contrast to non-pathogenic model organisms, C. neoformans Cdc42 proteins are not required for viability under non-stress conditions but are required for resistance to high temperature. The paralogues play differential roles in actin and septin organization and act downstream of C. neoformans Ras1 to regulate its morphogenesis sub-pathway, but not its effects on mating. Cdc42, and not Cdc420, is upregulated in response to temperature stress and is required for virulence in a murine model of cryptococcosis. The C. neoformans Cdc42 proteins likely perform complementary functions with other Rho-like GTPases to control cell polarity, septin organization and hyphal transitions that allow survival in the environment and in the host.
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Affiliation(s)
- Elizabeth R Ballou
- Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
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48
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Böhmer C, Ripp C, Bölker M. The germinal centre kinase Don3 triggers the dynamic rearrangement of higher-order septin structures during cytokinesis in Ustilago maydis. Mol Microbiol 2009; 74:1484-96. [PMID: 19906182 DOI: 10.1111/j.1365-2958.2009.06948.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The dimorphic phytopathogenic fungus Ustilago maydis grows in its haploid phase by budding. Cytokinesis and separation of daughter cells are accomplished by the consecutive formation of two distinct septa. Here, we show that both septation events involve the dynamic rearrangement of septin assemblies from hourglass-shaped collars into ring-like structures. Using a chemical genetic approach we demonstrate that the germinal centre kinase Don3 triggers this septin reorganization during secondary septum formation. Although chemical inhibition of an analogue-sensitive version of Don3 prevented septation, a stable septin collar was assembled at the presumptive septation site. Interestingly, the essential light chain of type II myosin, Cdc4, was already associated with this septin collar. Release of Don3 kinase inhibition triggered immediate dispersal of septin filaments and concomitant incorporation of Cdc4 into a contractile actomyosin ring, which also contained the F-BAR domain protein Cdc15. Inhibition of actin polymerization or deletion of the cdc15 gene, did not affect assembly of the initial collar consisting of septin and myosin light chain. However, reassembly of septin filaments into a ring-like structure was prevented in the absence of either F-actin or Cdc15, indicating that septin ring formation in U. maydis depends on a functional contractile actomyosin ring.
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Affiliation(s)
- Christian Böhmer
- Department of Biology, Philipps-University Marburg, Karl-von-Frisch-Str. 8, D-35032 Marburg, Germany
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Hoffman-Sommer M, Kucharczyk R, Piekarska I, Kozlowska E, Rytka J. Mutations in the Saccharomyces cerevisiae vacuolar fusion proteins Ccz1, Mon1 and Ypt7 cause defects in cell cycle progression in a num1Δ background. Eur J Cell Biol 2009; 88:639-52. [DOI: 10.1016/j.ejcb.2009.07.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2009] [Revised: 06/29/2009] [Accepted: 07/03/2009] [Indexed: 01/07/2023] Open
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Cao L, Yu W, Wu Y, Yu L. The evolution, complex structures and function of septin proteins. Cell Mol Life Sci 2009; 66:3309-23. [PMID: 19597764 PMCID: PMC11115805 DOI: 10.1007/s00018-009-0087-2] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2009] [Revised: 06/21/2009] [Accepted: 06/25/2009] [Indexed: 12/14/2022]
Abstract
The septin family is a conserved GTP-binding protein family and was originally discovered through genetic screening for budding yeast mutants. Septins are implicated in many cellular processes in fungi and metazoa. The function of septins usually depends on septin assembling into oligomeric complexes and highly ordered polymers. The expansion of the septin gene number in vertebrates increased the complex diversity of septins. In this review, we first discuss the evolution, structures and assembly of septin proteins in yeast and metazoa. Then, we review the function of septin proteins in cytokinesis, membrane remodeling and compartmentalization.
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Affiliation(s)
- Lihuan Cao
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Sciences, Fudan University, 200433 Shanghai, People’s Republic of China
| | - Wenbo Yu
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Sciences, Fudan University, 200433 Shanghai, People’s Republic of China
| | - Yanhua Wu
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Sciences, Fudan University, 200433 Shanghai, People’s Republic of China
| | - Long Yu
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Sciences, Fudan University, 200433 Shanghai, People’s Republic of China
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