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Fission Yeast Rho1p-GEFs: From Polarity and Cell Wall Synthesis to Genome Stability. Int J Mol Sci 2022; 23:ijms232213888. [PMID: 36430366 PMCID: PMC9697909 DOI: 10.3390/ijms232213888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 11/07/2022] [Accepted: 11/09/2022] [Indexed: 11/16/2022] Open
Abstract
Rho1p is a membrane-associated protein that belongs to the Rho family of small GTPases. These proteins coordinate processes such as actin remodelling and polarised secretion to maintain the shape and homeostasis of yeast cells. In response to extracellular stimuli, Rho1p undergoes conformational switching between a guanosine triphosphate (GTP)-bound active state and a guanosine diphosphate (GDP)-bound inactive state. Cycling is improved with guanine nucleotide exchange factor (GEF) activity necessary to activate signalling and GTPase activating protein (GAP) activity required for subsequent signal depletion. This review focuses on fission yeast Rho1p GEFs, Rgf1p, Rgf2p, and Rgf3p that belong to the family of DH-PH domain-containing Dbl-related GEFs. They are multi-domain proteins that detect biological signals that induce or inhibit their catalytic activity over Rho1p. Each of them activates Rho1p in different places and times. Rgf1p acts preferentially during polarised growth. Rgf2p is required for sporulation, and Rgf3p plays an essential function in septum synthesis. In addition, we outline the noncanonical roles of Rho1p-GEFs in genomic instability.
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Rich-Robinson J, Russell A, Mancini E, Das M. Cdc42 reactivation at growth sites is regulated by local cell-cycle-dependent loss of its GTPase-activating protein Rga4 in fission yeast. J Cell Sci 2021; 134:272049. [PMID: 34523683 DOI: 10.1242/jcs.259291] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 08/18/2021] [Indexed: 12/18/2022] Open
Abstract
In fission yeast, polarized cell growth stops during division and resumes after cytokinesis completes and cells separate. It is unclear how growth reactivation is timed to occur immediately after cell separation. We uncoupled these sequential events by delaying cytokinesis with a temporary Latrunculin A treatment. Mitotic cells recovering from treatment initiate end growth during septation, displaying a polar elongation simultaneous with septation (PrESS) phenotype. PrESS cell ends reactivate Cdc42, a major regulator of polarized growth, during septation, but at a fixed time after anaphase B. A candidate screen implicates Rga4, a negative regulator of Cdc42, in this process. We show that Rga4 appears punctate at the cell sides during G2, but is diffuse during mitosis, extending to the ends. Although the Morphogenesis Orb6 (MOR) pathway is known to promote cell separation and growth by activating protein synthesis, we find that, for polarized growth, removal of Rga4 from the ends is also necessary. Therefore, we propose that growth resumes after division once the MOR pathway is activated and the ends lose Rga4 in a cell-cycle-dependent manner.
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Affiliation(s)
- Julie Rich-Robinson
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
| | - Afton Russell
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
| | - Eleanor Mancini
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
| | - Maitreyi Das
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
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Roncero C, Celador R, Sánchez N, García P, Sánchez Y. The Role of the Cell Integrity Pathway in Septum Assembly in Yeast. J Fungi (Basel) 2021; 7:jof7090729. [PMID: 34575767 PMCID: PMC8471060 DOI: 10.3390/jof7090729] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 08/30/2021] [Accepted: 08/31/2021] [Indexed: 12/22/2022] Open
Abstract
Cytokinesis divides a mother cell into two daughter cells at the end of each cell cycle and proceeds via the assembly and constriction of a contractile actomyosin ring (CAR). Ring constriction promotes division furrow ingression, after sister chromatids are segregated to opposing sides of the cleavage plane. Cytokinesis contributes to genome integrity because the cells that fail to complete cytokinesis often reduplicate their chromosomes. While in animal cells, the last steps of cytokinesis involve extracellular matrix remodelling and mid-body abscission, in yeast, CAR constriction is coupled to the synthesis of a polysaccharide septum. To preserve cell integrity during cytokinesis, fungal cells remodel their cell wall through signalling pathways that connect receptors to downstream effectors, initiating a cascade of biological signals. One of the best-studied signalling pathways is the cell wall integrity pathway (CWI) of the budding yeast Saccharomyces cerevisiae and its counterpart in the fission yeast Schizosaccharomyces pombe, the cell integrity pathway (CIP). Both are signal transduction pathways relying upon a cascade of MAP kinases. However, despite strong similarities in the assembly of the septa in both yeasts, there are significant mechanistic differences, including the relationship of this process with the cell integrity signalling pathways.
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Gene Expression of Putative Pathogenicity-Related Genes in Verticillium dahliae in Response to Elicitation with Potato Extracts and during Infection Using Quantitative Real-Time PCR. Pathogens 2021; 10:pathogens10050510. [PMID: 33922492 PMCID: PMC8146963 DOI: 10.3390/pathogens10050510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 04/19/2021] [Accepted: 04/21/2021] [Indexed: 11/17/2022] Open
Abstract
Quantitative real-time PCR was used to monitor the expression of 15 Verticillium dahliae's genes, putatively involved in pathogenicity, highly (HAV) and weakly aggressive (WAV) V. dahliae isolates after either (i) elicitation with potato leaf, stem, or root extracts, or (ii) inoculation of potato detached petioles. These genes, i.e., coding for Ras-GAP-like protein, serine/threonine protein kinase, Ubiquitin-conjugating enzyme variant-MMS2, NADH-ubiquinone oxidoreductase, Thioredoxin, Pyruvate dehydrogenase E1 VdPDHB, myo-inositol 2-dehydrogenase, and HAD-superfamily hydrolase, showed differential upregulation in the HAV versus WAV isolate in response to plant extracts or after inoculation of potato leaf petioles. This suggests their potential involvement in the observed differential aggressiveness between isolates. However, other genes like glucan endo-1,3-alpha-glucosidase and nuc-1 negative regulatory protein VdPREG showed higher activity in the WAV than in the HAV in response to potato extracts and/or during infection. This, in contrast, may suggest a role in their lower aggressiveness. These findings, along with future functional analysis of selected genes, will contribute to improving our understanding of V. dahliae's pathogenesis. For example, expression of VdPREG negatively regulates phosphorus-acquisition enzymes, which may indicate a lower phosphorus acquisition activity in the WAV. Therefore, integrating the knowledge about the activity of both genes enhancing pathogenicity and those restraining it will provide a guild line for further functional characterization of the most critical genes, thus driving new ideas towards better Verticillium wilt management.
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Chew TG, Lim TC, Osaki Y, Huang J, Kamnev A, Hatano T, Osumi M, Balasubramanian MK. Inhibition of cell membrane ingression at the division site by cell walls in fission yeast. Mol Biol Cell 2020; 31:2306-2314. [PMID: 32755476 PMCID: PMC7851958 DOI: 10.1091/mbc.e20-04-0245] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Eukaryotic cells assemble actomyosin rings during cytokinesis to function as force-generating machines to drive membrane invagination and to counteract the intracellular pressure and the cell surface tension. How the extracellular matrix affects actomyosin ring contraction has not been fully explored. While studying the Schizosaccharomyces pombe 1,3-β-glucan-synthase mutant cps1-191, which is defective in division septum synthesis and arrests with a stable actomyosin ring, we found that weakening of the extracellular glycan matrix caused the generated spheroplasts to divide under the nonpermissive condition. This nonmedial slow division was dependent on a functional actomyosin ring and vesicular trafficking, but independent of normal septum synthesis. Interestingly, the high intracellular turgor pressure appears to play a minimal role in inhibiting ring contraction in the absence of cell wall remodeling in cps1-191 mutants, as decreasing the turgor pressure alone did not enable spheroplast division. We propose that during cytokinesis, the extracellular glycan matrix restricts actomyosin ring contraction and membrane ingression, and remodeling of the extracellular components through division septum synthesis relieves the inhibition and facilitates actomyosin ring contraction.
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Affiliation(s)
- Ting Gang Chew
- Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, CV4 7AL, United Kingdom.,ZJU-UoE Institute, Zhejiang University School of Medicine, International Campus, Zhejiang University, Zhejiang 314400, People's Republic of China
| | - Tzer Chyn Lim
- Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, CV4 7AL, United Kingdom
| | - Yumi Osaki
- Integrated Imaging Research Support, Tokyo 102-0093, Japan
| | - Junqi Huang
- Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, CV4 7AL, United Kingdom
| | - Anton Kamnev
- Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, CV4 7AL, United Kingdom
| | - Tomoyuki Hatano
- Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, CV4 7AL, United Kingdom
| | - Masako Osumi
- Integrated Imaging Research Support, Tokyo 102-0093, Japan.,Laboratory of Electron Microscopy/Bio-imaging Center, Japan Women's University, Tokyo 112-8681, Japan
| | - Mohan K Balasubramanian
- Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, CV4 7AL, United Kingdom
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Onwubiko UN, Rich-Robinson J, Mustaf RA, Das ME. Cdc42 promotes Bgs1 recruitment for septum synthesis and glucanase localization for cell separation during cytokinesis in fission yeast. Small GTPases 2020; 12:257-264. [PMID: 32182184 DOI: 10.1080/21541248.2020.1743926] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Cytokinesis in fission yeast involves actomyosin ring constriction concurrent to septum synthesis followed by septum digestion resulting in cell separation. A recent report indicates that endocytosis is required for septum synthesis and cell separation. The conserved GTPase Cdc42 is required for membrane trafficking and promotes endocytosis. Cdc42 is activated by Guanine nucleotide exchange factors (GEFs). Cdc42 GEFs have been shown to promote timely initiation of septum synthesis and proper septum morphology. Here we show that Cdc42 promotes the recruitment of the major primary septum synthesizing enzyme Bgs1 and consequent ring constriction. Cdc42 is also required for proper localization of the septum digesting glucanases at the division site. Thus, Cdc42 is required to promote multiple steps during cytokinesis.
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Affiliation(s)
- Udo N Onwubiko
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, USA
| | - Julie Rich-Robinson
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, USA
| | - Rose Albu Mustaf
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, USA
| | - Maitreyi E Das
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, USA
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Hercyk BS, Onwubiko UN, Das ME. Coordinating septum formation and the actomyosin ring during cytokinesis in Schizosaccharomyces pombe. Mol Microbiol 2019; 112:1645-1657. [PMID: 31533197 PMCID: PMC6904431 DOI: 10.1111/mmi.14387] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/12/2019] [Indexed: 01/08/2023]
Abstract
During cytokinesis, animal and fungal cells form a membrane furrow via actomyosin ring constriction. Our understanding of actomyosin ring-driven cytokinesis stems extensively from the fission yeast model system. However, unlike animal cells, actomyosin ring constriction occurs simultaneously with septum formation in fungi. While the formation of an actomyosin ring is essential for cytokinesis in fission yeast, proper furrow formation also requires septum deposition. The molecular mechanisms of spatiotemporal coordination of septum deposition with actomyosin ring constriction are poorly understood. Although the role of the actomyosin ring as a mechanical structure driving furrow formation is better understood, its role as a spatiotemporal landmark for septum deposition is not widely discussed. Here we review and discuss the recent advances describing how the actomyosin ring spatiotemporally regulates membrane traffic to promote septum-driven cytokinesis in fission yeast. Finally, we explore emerging questions in cytokinesis, and discuss the role of extracellular matrix during cytokinesis in other organisms.
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Affiliation(s)
- Brian S Hercyk
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, 37996, USA
| | - Udo N Onwubiko
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, 37996, USA
| | - Maitreyi E Das
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, 37996, USA
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8
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Abstract
In many yeast and fungi, β-(1,3)-glucan and chitin are essential components of the cell wall, an important structure that surrounds cells and which is responsible for their mechanical protection and necessary for maintaining the cellular shape. In addition, the cell wall is a dynamic structure that needs to be remodelled along with the different phases of the fungal life cycle or in response to extracellular stimuli. Since β-(1,3)-glucan and chitin perform a central structural role in the assembly of the cell wall, it has been postulated that β-(1,3)-glucanases and chitinases should perform an important function in cell wall softening and remodelling. This review focusses on fungal glucanases and chitinases and their role during fungal morphogenesis.
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Affiliation(s)
- César Roncero
- Instituto de Biología Funcional Y Genómica (IBFG), Consejo Superior de Investigaciones Científicas/Universidad de Salamanca, Salamanca, Spain
| | - Carlos R Vázquez de Aldana
- Instituto de Biología Funcional Y Genómica (IBFG), Consejo Superior de Investigaciones Científicas/Universidad de Salamanca, Salamanca, Spain.
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9
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Pérez P, Cortés JC, Cansado J, Ribas JC. Fission yeast cell wall biosynthesis and cell integrity signalling. ACTA ACUST UNITED AC 2018; 4:1-9. [PMID: 32743131 PMCID: PMC7388972 DOI: 10.1016/j.tcsw.2018.10.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 10/04/2018] [Accepted: 10/09/2018] [Indexed: 02/02/2023]
Abstract
The cell wall is a structure external to the plasma membrane that is essential for the survival of the fungi. This polysaccharidic structure confers resistance to the cell internal turgor pressure and protection against mechanical injury. The fungal wall is also responsible for the shape of these organisms due to different structural polysaccharides, such as β-(1,3)-glucan, which form fibers and confer rigidity to the cell wall. These polysaccharides are not present in animal cells and therefore they constitute excellent targets for antifungal chemotherapies. Cell wall damage leads to the activation of MAPK signaling pathways, which respond to the damage by activating the repair of the wall and the maintenance of the cell integrity. Fission yeast Schizosaccharomyces pombe is a model organism for the study morphogenesis, cell wall, and how different inputs might regulate this structure. We present here a short overview of the fission yeast wall composition and provide information about the main biosynthetic activities that assemble this cell wall. Additionally, we comment the recent advances in the knowledge of the cell wall functions and discuss the role of the cell integrity MAPK signaling pathway in the regulation of fission yeast wall.
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Affiliation(s)
- Pilar Pérez
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas and Universidad de Salamanca, 37007 Salamanca, Spain
- Corresponding author.
| | - Juan C.G. Cortés
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas and Universidad de Salamanca, 37007 Salamanca, Spain
| | - Jose Cansado
- Yeast Physiology Group, Department of Genetics and Microbiology, Facultad de Biología, Universidad de Murcia, 30071 Murcia, Spain
| | - Juan C. Ribas
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas and Universidad de Salamanca, 37007 Salamanca, Spain
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10
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Abstract
The molecular composition of the cell wall is critical for the biology and ecology of each fungal species. Fungal walls are composed of matrix components that are embedded and linked to scaffolds of fibrous load-bearing polysaccharides. Most of the major cell wall components of fungal pathogens are not represented in humans, other mammals, or plants, and therefore the immune systems of animals and plants have evolved to recognize many of the conserved elements of fungal walls. For similar reasons the enzymes that assemble fungal cell wall components are excellent targets for antifungal chemotherapies and fungicides. However, for fungal pathogens, the cell wall is often disguised since key signature molecules for immune recognition are sometimes masked by immunologically inert molecules. Cell wall damage leads to the activation of sophisticated fail-safe mechanisms that shore up and repair walls to avoid catastrophic breaching of the integrity of the surface. The frontiers of research on fungal cell walls are moving from a descriptive phase defining the underlying genes and component parts of fungal walls to more dynamic analyses of how the various components are assembled, cross-linked, and modified in response to environmental signals. This review therefore discusses recent advances in research investigating the composition, synthesis, and regulation of cell walls and how the cell wall is targeted by immune recognition systems and the design of antifungal diagnostics and therapeutics.
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11
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Abstract
The molecular composition of the cell wall is critical for the biology and ecology of each fungal species. Fungal walls are composed of matrix components that are embedded and linked to scaffolds of fibrous load-bearing polysaccharides. Most of the major cell wall components of fungal pathogens are not represented in humans, other mammals, or plants, and therefore the immune systems of animals and plants have evolved to recognize many of the conserved elements of fungal walls. For similar reasons the enzymes that assemble fungal cell wall components are excellent targets for antifungal chemotherapies and fungicides. However, for fungal pathogens, the cell wall is often disguised since key signature molecules for immune recognition are sometimes masked by immunologically inert molecules. Cell wall damage leads to the activation of sophisticated fail-safe mechanisms that shore up and repair walls to avoid catastrophic breaching of the integrity of the surface. The frontiers of research on fungal cell walls are moving from a descriptive phase defining the underlying genes and component parts of fungal walls to more dynamic analyses of how the various components are assembled, cross-linked, and modified in response to environmental signals. This review therefore discusses recent advances in research investigating the composition, synthesis, and regulation of cell walls and how the cell wall is targeted by immune recognition systems and the design of antifungal diagnostics and therapeutics.
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Affiliation(s)
- Neil A R Gow
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen AB252ZD, United Kingdom
| | | | - Carol A Munro
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen AB252ZD, United Kingdom
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12
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Sethi K, Palani S, Cortés JCG, Sato M, Sevugan M, Ramos M, Vijaykumar S, Osumi M, Naqvi NI, Ribas JC, Balasubramanian M. A New Membrane Protein Sbg1 Links the Contractile Ring Apparatus and Septum Synthesis Machinery in Fission Yeast. PLoS Genet 2016; 12:e1006383. [PMID: 27749909 PMCID: PMC5066963 DOI: 10.1371/journal.pgen.1006383] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 09/23/2016] [Indexed: 01/14/2023] Open
Abstract
Cytokinesis in many organisms requires a plasma membrane anchored actomyosin ring, whose contraction facilitates cell division. In yeast and fungi, actomyosin ring constriction is also coordinated with division septum assembly. How the actomyosin ring interacts with the plasma membrane and the plasma membrane-localized septum synthesizing machinery remains poorly understood. In Schizosaccharomyces pombe, an attractive model organism to study cytokinesis, the β-1,3-glucan synthase Cps1p / Bgs1p, an integral membrane protein, localizes to the plasma membrane overlying the actomyosin ring and is required for primary septum synthesis. Through a high-dosage suppressor screen we identified an essential gene, sbg1+ (suppressor of beta glucan synthase 1), which suppressed the colony formation defect of Bgs1-defective cps1-191 mutant at higher temperatures. Sbg1p, an integral membrane protein, localizes to the cell ends and to the division site. Sbg1p and Bgs1p physically interact and are dependent on each other to localize to the division site. Loss of Sbg1p results in an unstable actomyosin ring that unravels and slides, leading to an inability to deposit a single contiguous division septum and an important reduction of the β-1,3-glucan proportion in the cell wall, coincident with that observed in the cps1-191 mutant. Sbg1p shows genetic and / or physical interaction with Rga7p, Imp2p, Cdc15p, and Pxl1p, proteins known to be required for actomyosin ring integrity and efficient septum synthesis. This study establishes Sbg1p as a key member of a group of proteins that link the plasma membrane, the actomyosin ring, and the division septum assembly machinery in fission yeast. Cell division in many organisms requires the function of an actomyosin ring, an apparatus that resembles the force generating machinery in the muscle. This ring apparatus is attached to the cell periphery (cell membranes) such that when it contracts, it brings the cell periphery together with it, leading to cell division. How the actomyosin ring is attached to the cell membrane at the division site is unknown. In this manuscript, we identify and describe Sbg1, a protein that links the actomyosin ring and the cell membranes since Sbg1 has a sequence that allows it to be inserted into the cell membrane. Sbg1 specifically localizes to the cell division site and also cooperates with a cell wall biosynthetic enzyme Bgs1 to achieve cell division. Consistently, in the absence of Sbg1, cells fail to divide leading to lethality. Sbg1 interacts with a number of cell division proteins, such as Cdc15, Rga7, Imp2, and Pxl1, to achieve its function as a bridge between the cell membrane and the actomyosin ring. Our work identifies a direct molecular link between the actomyosin ring and the cell membranes, explaining how ring contraction leads to inward movement of the cell periphery.
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Affiliation(s)
- Kriti Sethi
- Temasek Life Sciences Laboratory, National University of Singapore, 1 Research Link, Singapore
- Department of Biological Sciences, National University of Singapore, Singapore
| | - Saravanan Palani
- Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, United Kingdom
| | - Juan C. G. Cortés
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Cinetificas/Universidad de Salamanca, Salamanca, Spain
| | - Mamiko Sato
- Laboratory of Electron Microscopy/Bio-imaging Centre, and Department of Chemical and Biological Sciences, Faculty of Sciences, Japan Women’s University, Mejirodai, Bunkyo-ku, Tokyo, Japan
| | - Mayalagu Sevugan
- Temasek Life Sciences Laboratory, National University of Singapore, 1 Research Link, Singapore
| | - Mariona Ramos
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Cinetificas/Universidad de Salamanca, Salamanca, Spain
| | - Shruthi Vijaykumar
- Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, United Kingdom
| | - Masako Osumi
- Laboratory of Electron Microscopy/Bio-imaging Centre, and Department of Chemical and Biological Sciences, Faculty of Sciences, Japan Women’s University, Mejirodai, Bunkyo-ku, Tokyo, Japan
- NPO Integrated Imaging Research Support, Hirakawa-cho, Chiyoda-ku, Tokyo, Japan
| | - Naweed I. Naqvi
- Temasek Life Sciences Laboratory, National University of Singapore, 1 Research Link, Singapore
- Department of Biological Sciences, National University of Singapore, Singapore
| | - Juan Carlos Ribas
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Cinetificas/Universidad de Salamanca, Salamanca, Spain
| | - Mohan Balasubramanian
- Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, United Kingdom
- * E-mail:
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13
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Domizio P, Liu Y, Bisson LF, Barile D. Cell wall polysaccharides released during the alcoholic fermentation by Schizosaccharomyces pombe and S. japonicus: quantification and characterization. Food Microbiol 2016; 61:136-149. [PMID: 27697163 DOI: 10.1016/j.fm.2016.08.010] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 08/26/2016] [Accepted: 08/27/2016] [Indexed: 01/09/2023]
Abstract
The present work demonstrates that yeasts belonging to the Schizosaccharomyces genus release a high quantity of polysaccharides of cell wall origin starting from the onset of the alcoholic fermentation. By the end of the alcoholic fermentation, all of the Schizosaccharomyces yeast strains released a quantity of polysaccharides approximately 3-7 times higher than that released by a commercial Saccharomyces cerevisiae yeast strain under the same fermentative conditions of synthetic juice. A higher content of polysaccharide was found in media fermented by Schizosaccharomyces japonicus with respect to that of Schizosaccharomyces pombe. Some of the strains evaluated were also able to produce high levels of pyruvic acid, which has been shown to be an important compound for color stability of wine. The presence of strains with different malic acid consumption patterns along with high polysaccharide release would enable production of naturally modified wines with enhanced mouth feel and reduced acidity. The chemical analysis of the released polysaccharides demonstrated divergence between the two yeast species S. pombe and S. japonicus. A different mannose/galactose ratio and a different percentage of proteins was observed on the polysaccharides released by S. pombe as compared to S. japonicus. Analysis of the proteins released in the media revealed the presence of a glycoprotein with a molecular size around 32-33 kDa only for the species S. japonicus. Mass spectrometry analysis of carbohydrate moieties showed similar proportions among the N-glycan chains released in the media by both yeast species but differences between the two species were also observed. These observations suggest a possible role of rapid MALDI-TOF screening of N-glycans compositional fingerprint as a taxonomic tool for this genus. Polysaccharides release in the media, in particular galactomannoproteins in significant amounts, could make these yeasts particularly interesting also for the industrial production of exogenous polysaccharide preparations.
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Affiliation(s)
- P Domizio
- Department of Viticulture & Enology, University of California-Davis, Davis, CA 95616, USA; Dipartimento di Gestione dei Sistemi Agrari, Alimentari e Forestali (GESAAF), Università degli Studi di Firenze, 50144 Firenze, Italy.
| | - Y Liu
- Department of Foods Science & Technology, University of California-Davis, Davis, CA 95616, USA
| | - L F Bisson
- Department of Viticulture & Enology, University of California-Davis, Davis, CA 95616, USA
| | - D Barile
- Department of Foods Science & Technology, University of California-Davis, Davis, CA 95616, USA; Foods for Health Institute, University of California-Davis, Davis, CA 95616, USA
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14
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Buddana SK, Reddy Shetty P, Raja Surya Krothapalli SR. An endolytic mutanase from novel strain Paracoccus mutanolyticus: its application potential in dentistry. J Med Microbiol 2016; 65:985-991. [PMID: 27452833 DOI: 10.1099/jmm.0.000321] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Mutanase, α-(1→3)-glucanase, belonging to the family glucanohydrolase, catalyses mutan [α-(1→3)-glucan] synthesized by cariogenic streptococci and hence has potential in caries prophylaxis. A novel bacterial strain with potential to produce higher mutanase (glucanohydrolase) activity was isolated from soils contaminated with cellulosic waste. One of the isolated strains, RSP-02, was subjected to biochemical and 16S rRNA molecular analysis, and we noticed that it belongs to the genus Paracoccus. The mutanase production (800- 1200 U l-1) in this strain was growth associated and substrate induced, and the activity was comparable with the strains reported earlier. The enzyme displayed a molecular mass of 138 kDa by native PAGE studies, showed endolytic activity and produced nigerose as end product. In vitro studies revealed production of 140±2.82 µg of glucose equivalents in 30 min from the biofilm formed on glass surface indicating its potentiality in dentistry. To the best of our knowledge, this is the first report on the production of mutanase by Paracoccus sp.; hence, this isolated bacterial strain is designated as Paracoccus mutanolyticus RSP-02.
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Affiliation(s)
- Sudheer Kumar Buddana
- Academy of Scientific and Innovative Research, New Delhi, India.,Bioengineering and Environmental Sciences, CSIR-Indian Institute of Chemical Technology, Hyderabad, India
| | - Prakasham Reddy Shetty
- Bioengineering and Environmental Sciences, CSIR-Indian Institute of Chemical Technology, Hyderabad, India
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15
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Pérez P, Cortés JCG, Martín-García R, Ribas JC. Overview of fission yeast septation. Cell Microbiol 2016; 18:1201-7. [PMID: 27155541 DOI: 10.1111/cmi.12611] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Revised: 05/02/2016] [Accepted: 05/05/2016] [Indexed: 02/04/2023]
Abstract
Cytokinesis is the final process of the vegetative cycle, which divides a cell into two independent daughter cells once mitosis is completed. In fungi, as in animal cells, cytokinesis requires the formation of a cleavage furrow originated by constriction of an actomyosin ring which is connected to the plasma membrane and causes its invagination. Additionally, because fungal cells have a polysaccharide cell wall outside the plasma membrane, cytokinesis requires the formation of a septum coincident with the membrane ingression. Fission yeast Schizosaccharomyces pombe is a unicellular, rod-shaped fungus that has become a popular model organism for the study of actomyosin ring formation and constriction during cell division. Here we review the current knowledge of the septation and separation processes in this fungus, as well as recent advances in understanding the functional interaction between the transmembrane enzymes that build the septum and the actomyosin ring proteins.
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Affiliation(s)
- Pilar Pérez
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Salamanca, Salamanca, 37007, Spain
| | - Juan C G Cortés
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Salamanca, Salamanca, 37007, Spain
| | - Rebeca Martín-García
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Salamanca, Salamanca, 37007, Spain
| | - Juan C Ribas
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Salamanca, Salamanca, 37007, Spain
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16
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Wang Z, Gu Z, Shen Y, Wang Y, Li J, Lv H, Huo K. The Natural Product Resveratrol Inhibits Yeast Cell Separation by Extensively Modulating the Transcriptional Landscape and Reprogramming the Intracellular Metabolome. PLoS One 2016; 11:e0150156. [PMID: 26950930 PMCID: PMC4780762 DOI: 10.1371/journal.pone.0150156] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 02/10/2016] [Indexed: 12/28/2022] Open
Abstract
An increasing number of studies have shown that the promising compound resveratrol treats multiple diseases, such as cancer and aging; however, the resveratrol mode-of-action (MoA) remains largely unknown. Here, by virtue of multiple omics approaches, we adopted fission yeast as a model system with the goal of dissecting the common MoA of the anti-proliferative activity of resveratrol. We found that the anti-proliferative activity of resveratrol is mainly due to its unique role of inhibiting the separation of sister cells, similar phenotype with the C2H2 zinc finger transcription factor Ace2 knock-out strain. Microarray analysis shown that resveratrol has extensive impact on the fission yeast transcription levels. Among the changed gene's list, 40% of up-regulated genes are Core Environmental Stress Responses genes, and 57% of the down-regulated genes are periodically expressed. Moreover, resveratrol leverages the metabolome, which unbalances the intracellular pool sizes of several classes of amino acids, nucleosides, sugars and lipids, thus reflecting the remodulated metabolic networks. The complexity of the resveratrol MoA displayed in previous reports and our work demonstrates that multiple omics approaches must be applied together to obtain a complete picture of resveratrol's anti-proliferative function.
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Affiliation(s)
- Zhe Wang
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, 2005 Song-Hu Road, Shanghai, 200438, China
- Division of Infectious Diseases, Weill Medical College of Cornell University, 413 E 69th St, New York, NY, 10021, United States of America
- * E-mail: (KH); (ZW); (HL)
| | - Zhongkai Gu
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, 2005 Song-Hu Road, Shanghai, 200438, China
- Institutes of Biomedical Sciences, Fudan University, 130 Dong-An Road, Shanghai, 200032, China
| | - Yan Shen
- Institutes of Biomedical Sciences, Fudan University, 130 Dong-An Road, Shanghai, 200032, China
| | - Yang Wang
- Institutes of Biomedical Sciences, Fudan University, 130 Dong-An Road, Shanghai, 200032, China
| | - Jing Li
- Department of Biological Sciences and Biotechnology, State Key Laboratory of Biomembrane and Membrane Biotechnology, Tsinghua University, Beijing, 100084, China
| | - Hong Lv
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, 2005 Song-Hu Road, Shanghai, 200438, China
- * E-mail: (KH); (ZW); (HL)
| | - Keke Huo
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, 2005 Song-Hu Road, Shanghai, 200438, China
- * E-mail: (KH); (ZW); (HL)
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17
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Martín-García R, Santos B. The price of independence: cell separation in fission yeast. World J Microbiol Biotechnol 2016; 32:65. [PMID: 26931605 DOI: 10.1007/s11274-016-2021-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Accepted: 01/29/2016] [Indexed: 12/28/2022]
Abstract
The ultimate goal of cell division is to give rise to two viable independent daughter cells. A tight spatial and temporal regulation between chromosome segregation and cytokinesis ensures the viability of the daughter cells. Schizosaccharomyces pombe, commonly known as fission yeast, has become a leading model organism for studying essential and conserved mechanisms of the eukaryotic cell division process. Like many other eukaryotic cells it divides by binary fission and the cleavage furrow undergoes ingression due to the contraction of an actomyosin ring. In contrast to mammalian cells, yeasts as cell-walled organisms, also need to form a division septum made of cell wall material to complete the process of cytokinesis. The division septum is deposited behind the constricting ring and it will constitute the new ends of the daughter cells. Cell separation also involves cell wall degradation and this process should be precisely regulated to avoid cell lysis. In this review, we will give a brief overview of the whole cytokinesis process in fission yeast, from the positioning and assembly of the contractile ring to the final step of cell separation, and the problems generated when these processes are not precise.
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Affiliation(s)
- Rebeca Martín-García
- Instituto de Biología Funcional y Genómica (IBFG), Consejo Superior de Investigaciones Científicas, University of Salamanca, 37007, Salamanca, Spain
| | - Beatriz Santos
- Instituto de Biología Funcional y Genómica (IBFG), Consejo Superior de Investigaciones Científicas, University of Salamanca, 37007, Salamanca, Spain.
- Departamento de Microbiología y Genética, University of Salamanca, 37007, Salamanca, Spain.
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18
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Langner T, Göhre V. Fungal chitinases: function, regulation, and potential roles in plant/pathogen interactions. Curr Genet 2015; 62:243-54. [PMID: 26527115 DOI: 10.1007/s00294-015-0530-x] [Citation(s) in RCA: 101] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Revised: 10/20/2015] [Accepted: 10/22/2015] [Indexed: 12/13/2022]
Abstract
In the past decades our knowledge about fungal cell wall architecture increased tremendously and led to the identification of many enzymes involved in polysaccharide synthesis and remodeling, which are also of biotechnological interest. Fungal cell walls play an important role in conferring mechanic stability during cell division and polar growth. Additionally, in phytopathogenic fungi the cell wall is the first structure that gets into intimate contact with the host plant. A major constituent of fungal cell walls is chitin, a homopolymer of N-acetylglucosamine units. To ensure plasticity, polymeric chitin needs continuous remodeling which is maintained by chitinolytic enzymes, including lytic polysaccharide monooxygenases N-acetylglucosaminidases, and chitinases. Depending on the species and lifestyle of fungi, there is great variation in the number of encoded chitinases and their function. Chitinases can have housekeeping function in plasticizing the cell wall or can act more specifically during cell separation, nutritional chitin acquisition, or competitive interaction with other fungi. Although chitinase research made huge progress in the last decades, our knowledge about their role in phytopathogenic fungi is still scarce. Recent findings in the dimorphic basidiomycete Ustilago maydis show that chitinases play different physiological functions throughout the life cycle and raise questions about their role during plant-fungus interactions. In this work we summarize these functions, mechanisms of chitinase regulation and their putative role during pathogen/host interactions.
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Affiliation(s)
- Thorsten Langner
- Institute for Microbiology, Heinrich-Heine University Düsseldorf, Universitätsstr. 1, 40225, Düsseldorf, Germany
| | - Vera Göhre
- Institute for Microbiology, Heinrich-Heine University Düsseldorf, Universitätsstr. 1, 40225, Düsseldorf, Germany.
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19
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Suárez MB, Alonso-Nuñez ML, del Rey F, McInerny CJ, Vázquez de Aldana CR. Regulation of Ace2-dependent genes requires components of the PBF complex in Schizosaccharomyces pombe. Cell Cycle 2015; 14:3124-37. [PMID: 26237280 DOI: 10.1080/15384101.2015.1078035] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
The division cycle of unicellular yeasts is completed with the activation of a cell separation program that results in the dissolution of the septum assembled during cytokinesis between the 2 daughter cells, allowing them to become independent entities. Expression of the eng1(+) and agn1(+) genes, encoding the hydrolytic enzymes responsible for septum degradation, is activated at the end of each cell cycle by the transcription factor Ace2. Periodic ace2(+) expression is regulated by the transcriptional complex PBF (PCB Binding Factor), composed of the forkhead-like proteins Sep1 and Fkh2 and the MADS box-like protein Mbx1. In this report, we show that Ace2-dependent genes contain several combinations of motifs for Ace2 and PBF binding in their promoters. Thus, Ace2, Fkh2 and Sep1 were found to bind in vivo to the eng1(+) promoter. Ace2 binding was coincident with maximum level of eng1(+) expression, whereas Fkh2 binding was maximal when mRNA levels were low, supporting the notion that they play opposing roles. In addition, we found that the expression of eng1(+) and agn1(+) was differentially affected by mutations in PBF components. Interestingly, agn1(+) was a major target of Mbx1, since its ectopic expression resulted in the suppression of Mbx1 deletion phenotypes. Our results reveal a complex regulation system through which the transcription factors Ace2, Fkh2, Sep1 and Mbx1 in combination control the expression of the genes involved in separation at the end of the cell division cycle.
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Affiliation(s)
- M Belén Suárez
- a Instituto de Biología Funcional y Genómica; CSIC/Universidad de Salamanca ; Salamanca , Spain
| | | | - Francisco del Rey
- a Instituto de Biología Funcional y Genómica; CSIC/Universidad de Salamanca ; Salamanca , Spain
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20
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Pleszczyńska M, Wiater A, Janczarek M, Szczodrak J. (1→3)-α-D-Glucan hydrolases in dental biofilm prevention and control: A review. Int J Biol Macromol 2015; 79:761-78. [PMID: 26047901 DOI: 10.1016/j.ijbiomac.2015.05.052] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Revised: 05/28/2015] [Accepted: 05/29/2015] [Indexed: 11/27/2022]
Abstract
Dental plaque is a highly diverse biofilm, which has an important function in maintenance of oral and systemic health but in some conditions becomes a cause of oral diseases. In addition to mechanical plaque removal, current methods of dental plaque control involve the use of chemical agents against biofilm pathogens, which however, given the complexity of the oral microbiome, is not sufficiently effective. Hence, there is a need for development of new anti-biofilm approaches. Polysaccharides, especially (1→3),(1→6)-α-D-glucans, which are key structural and functional constituents of the biofilm matrix, seem to be a good target for future therapeutic strategies. In this review, we have focused on (1→3)-α-glucanases, which can limit the cariogenic properties of the dental plaque extracellular polysaccharides. These enzymes are not widely known and have not been exhaustively described in literature.
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Affiliation(s)
- Małgorzata Pleszczyńska
- Department of Industrial Microbiology, Maria Curie-Skłodowska University, Akademicka 19, 20-033 Lublin, Poland.
| | - Adrian Wiater
- Department of Industrial Microbiology, Maria Curie-Skłodowska University, Akademicka 19, 20-033 Lublin, Poland.
| | - Monika Janczarek
- Department of Genetics and Microbiology, Maria Curie-Skłodowska University, Akademicka 19, 20-033 Lublin, Poland.
| | - Janusz Szczodrak
- Department of Industrial Microbiology, Maria Curie-Skłodowska University, Akademicka 19, 20-033 Lublin, Poland.
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21
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Pérez P, Portales E, Santos B. Rho4 interaction with exocyst and septins regulates cell separation in fission yeast. MICROBIOLOGY-SGM 2015; 161:948-959. [PMID: 25724972 DOI: 10.1099/mic.0.000062] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Accepted: 02/18/2015] [Indexed: 12/17/2022]
Abstract
Rho GTPases are small proteins present in all eukaryotic cells, from yeast to mammals, with a function in actin organization and morphogenetic processes. Schizosaccharomyces pombe Rho4 is not essential but it displays a role during cell separation at high temperature. In fact, Rho4 is involved in the secretion of the hydrolytic enzymes that are required for cell septum degradation during this process. In rho4Δ cells, vesicles accumulate in the septum area and the glucanases Eng1 and Agn1 are not secreted to the culture medium. The localization of Eng1 and Agn1 depends on the exocyst and the septins. The exocyst is a conserved multiprotein complex important for the targeting and fusion of Golgi-derived vesicles with the plasma membrane. Septins are a family of GTP-binding proteins conserved in eukaryotes that function during cytokinesis. Here we show that Rho4 is required for the proper localization of the exocyst and septins at high temperature. Moreover, pull-down experiments demonstrate that Rho4 can interact with exocyst subunits, such as Sec8 and Exo70, and septin proteins, such as Spn3. We observe that Sec8 preferentially binds to activated GTP-Rho4, suggesting that Sec8 could be an effector of this GTPase. We propose that the interaction of Rho4 with the exocyst and septins confers a precise regulation for the secretion of glucanases at the appropriate place and time during the cell cycle.
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Affiliation(s)
- Pilar Pérez
- Instituto de Biología Funcional y Genómica (IBFG), CSIC/Universidad de Salamanca, Avd. Zacarías González s/n, 37007 Salamanca, Spain
| | - Elvira Portales
- Instituto de Biología Funcional y Genómica (IBFG), CSIC/Universidad de Salamanca, Avd. Zacarías González s/n, 37007 Salamanca, Spain
| | - Beatriz Santos
- Departamento de Microbiología y Genética, Universidad de Salamanca, Avd. Zacarías González s/n, 37007 Salamanca, Spain.,Instituto de Biología Funcional y Genómica (IBFG), CSIC/Universidad de Salamanca, Avd. Zacarías González s/n, 37007 Salamanca, Spain
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22
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Characterization of the starvation-induced chitinase CfcA and α-1,3-glucanase AgnB of Aspergillus niger. Appl Microbiol Biotechnol 2014; 99:2209-23. [DOI: 10.1007/s00253-014-6062-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Revised: 08/25/2014] [Accepted: 08/29/2014] [Indexed: 10/24/2022]
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23
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Martín-García R, Coll PM, Pérez P. F-BAR domain protein Rga7 collaborates with Cdc15 and Imp2 to ensure proper cytokinesis in fission yeast. J Cell Sci 2014; 127:4146-58. [PMID: 25052092 DOI: 10.1242/jcs.146233] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
F-BAR domain proteins act as linkers between the cell cortex and cytoskeleton, and are involved in membrane binding and bending. Rga7 is one of the seven F-BAR proteins present in the fission yeast Schizosaccharomyces pombe. In addition to the F-BAR domain in the N-terminal region, Rga7 possesses a Rho GTPase-activating protein (GAP) domain at its C-terminus. We show here that Rga7 is necessary to prevent fragmentation of the contracting ring and incorrect septum synthesis. Accordingly, cultures of cells lacking Rga7 contain a higher percentage of dividing cells and more frequent asymmetric or aberrant septa, which ultimately might cause cell death. The Rga7 F-BAR domain is necessary for the protein localization to the division site and to the cell tips, and also for the Rga7 roles in cytokinesis. In contrast, Rga7 GAP catalytic activity seems to be dispensable. Moreover, we demonstrate that Rga7 cooperates with the two F-BAR proteins Cdc15 and Imp2 to ensure proper cytokinesis. We have also detected association of Rga7 with Imp2, and its binding partners Fic1 and Pxl1. Taken together, our findings suggest that Rga7 forms part of a protein complex that coordinates the late stages of cytokinesis.
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Affiliation(s)
- Rebeca Martín-García
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas/Universidad de Salamanca, 37007 Salamanca, Spain
| | - Pedro M Coll
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas/Universidad de Salamanca, 37007 Salamanca, Spain
| | - Pilar Pérez
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas/Universidad de Salamanca, 37007 Salamanca, Spain
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24
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Sipiczki M, Balazs A, Monus A, Papp L, Horvath A, Sveiczer A, Miklos I. Phylogenetic and comparative functional analysis of the cell-separation α-glucanase Agn1p in Schizosaccharomyces. MICROBIOLOGY-SGM 2014; 160:1063-1074. [PMID: 24699070 DOI: 10.1099/mic.0.077511-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The post-cytokinetic separation of cells in cell-walled organisms involves enzymic processes that degrade a specific layer of the division septum and the region of the mother cell wall that edges the septum. In the fission yeast Schizosaccharomyces pombe, the 1,3-α-glucanase Agn1p, originally identified as a mutanase-like glycoside hydrolase family 71 (GH71) enzyme, dissolves the mother cell wall around the septum edge. Our search in the genomes of completely sequenced fungi identified GH71 hydrolases in Basidiomycota, Taphrinomycotina and Pezizomycotina, but not in Saccharomycotina. The most likely Agn1p orthologues in Pezizomycotina species are not mutanases having mutanase-binding domains, but experimentally non-characterized hypothetical proteins that have no carbohydrate-binding domains. The analysis of the GH71 domains corroborated the phylogenetic relationships of the Schizosaccharomyces species determined by previous studies, but suggested a closer relationship to the Basidiomycota proteins than to the Ascomycota proteins. In the Schizosaccharomyces genus, the Agn1p proteins are structurally conserved: their GH71 domains are flanked by N-terminal secretion signals and C-terminal sequences containing the conserved block YNFNA(Y)/HTG. The inactivation of the agn1(Sj) gene in Schizosaccharomyces japonicus, the only true dimorphic member of the genus, caused a severe cell-separation defect in its yeast phase, but had no effect on the hyphal growth and yeast-to-mycelium transition. It did not affect the mycelium-to-yeast transition either, only delaying the separation of the yeast cells arising from the fragmenting hyphae. The heterologous expression of agn1(Sj) partially rescued the separation defect of the agn1Δ cells of Schizosaccharomyces pombe. The results presented indicate that the fission yeast Agn1p 1,3-α-glucanases of Schizosaccharomyces japonicus and Schizosaccharomyces pombe share conserved functions in the yeast phase.
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Affiliation(s)
- Matthias Sipiczki
- Department of Genetics and Applied Microbiology, University of Debrecen, 4032 Debrecen, Hungary
| | - Anita Balazs
- Department of Genetics and Applied Microbiology, University of Debrecen, 4032 Debrecen, Hungary
| | - Aniko Monus
- Department of Genetics and Applied Microbiology, University of Debrecen, 4032 Debrecen, Hungary
| | - Laszlo Papp
- Department of Genetics and Applied Microbiology, University of Debrecen, 4032 Debrecen, Hungary
| | - Anna Horvath
- Department of Applied Biotechnology and Food Science, Budapest University of Technology and Economics, 1111 Budapest, Hungary
| | - Akos Sveiczer
- Department of Applied Biotechnology and Food Science, Budapest University of Technology and Economics, 1111 Budapest, Hungary
| | - Ida Miklos
- Department of Genetics and Applied Microbiology, University of Debrecen, 4032 Debrecen, Hungary
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25
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de León N, Sharifmoghadam MR, Hoya M, Curto MÁ, Doncel C, Valdivieso MH. Regulation of cell wall synthesis by the clathrin light chain is essential for viability in Schizosaccharomyces pombe. PLoS One 2013; 8:e71510. [PMID: 23977061 PMCID: PMC3747244 DOI: 10.1371/journal.pone.0071510] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Accepted: 07/02/2013] [Indexed: 11/19/2022] Open
Abstract
The regulation of cell wall synthesis by the clathrin light chain has been addressed. Schizosaccharomyces pombe clc1Δ mutant was inviable in the absence of osmotic stabilization; when grown in sorbitol-supplemented medium clc1Δ cells grew slowly, formed aggregates, and had strong defects in morphology. Additionally, clc1Δ cells exhibited an altered cell wall composition. A mutant that allowed modulating the amount of Clc1p was created to analyze in more detail the dependence of cell wall synthesis on clathrin. A 40% reduction in the amount of Clc1p did not affect acid phosphatase secretion and bulk lipid internalization. Under these conditions, β(1,3)glucan synthase activity and cell wall synthesis were reduced. Also, the delivery of glucan synthases to the cell surface, and the secretion of the Eng1p glucanase were defective. These results suggest that the defects in the cell wall observed in the conditional mutant were due to a defective secretion of enzymes involved in the synthesis/remodelling of this structure, rather than to their endocytosis. Our results show that a reduction in the amount of clathrin that has minor effects on general vesicle trafficking has a strong impact on cell wall synthesis, and suggest that this is the reason for the lethality of clc1Δ cells in the absence of osmotic stabilization.
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Affiliation(s)
- Nagore de León
- Departamento de Microbiología y Genética/IBFG, Universidad de Salamanca/CSIC, Salamanca, Spain
| | | | - Marta Hoya
- Departamento de Microbiología y Genética/IBFG, Universidad de Salamanca/CSIC, Salamanca, Spain
| | - M.-Ángeles Curto
- Departamento de Microbiología y Genética/IBFG, Universidad de Salamanca/CSIC, Salamanca, Spain
| | - Cristina Doncel
- Departamento de Microbiología y Genética/IBFG, Universidad de Salamanca/CSIC, Salamanca, Spain
| | - M.-Henar Valdivieso
- Departamento de Microbiología y Genética/IBFG, Universidad de Salamanca/CSIC, Salamanca, Spain
- * E-mail:
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26
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Villalobos-Duno H, San-Blas G, Paulinkevicius M, Sánchez-Martín Y, Nino-Vega G. Biochemical characterization of Paracoccidioides brasiliensis α-1,3-glucanase Agn1p, and its functionality by heterologous Expression in Schizosaccharomyces pombe. PLoS One 2013; 8:e66853. [PMID: 23825576 PMCID: PMC3692533 DOI: 10.1371/journal.pone.0066853] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Accepted: 05/13/2013] [Indexed: 11/18/2022] Open
Abstract
α-1,3-Glucan is present as the outermost layer of the cell wall in the pathogenic yeastlike (Y) form of Paracoccidioides brasiliensis. Based on experimental evidence, this polysaccharide has been proposed as a fungal virulence factor. To degrade α-1,3-glucan and allow remodeling of the cell wall, α-1,3-glucanase is required. Therefore, the study of this enzyme, its encoding gene, and regulatory mechanisms, might be of interest to understand the morphogenesis and virulence process in this fungus. A single gene, orthologous to other fungal α-1,3-glucanase genes, was identified in the Paracoccidioides genome, and labeled AGN1. Transcriptional levels of AGN1 and AGS1 (α-1,3-glucan synthase-encoding gene) increased sharply when the pathogenic Y phase was cultured in the presence of 5% horse serum, a reported booster for cell wall α-1,3-glucan synthesis in this fungus. To study the biochemical properties of P. brasiliensis Agn1p, the enzyme was heterologously overexpressed, purified, and its activity profile determined by means of the degradation of carboxymethyl α-1,3-glucan (SCMG, chemically modified from P. brasiliensis α-1,3-glucan), used as a soluble substrate for the enzymatic reaction. Inhibition assays, thin layer chromatography and enzymatic reactions with alternative substrates (dextran, starch, chitin, laminarin and cellulose), showed that Agn1p displays an endolytic cut pattern and high specificity for SCMG. Complementation of a Schizosaccharomyces pombe agn1Δ strain with the P. brasiliensis AGN1 gene restored the wild type phenotype, indicating functionality of the gene, suggesting a possible role of Agn1p in the remodeling of P. brasiliensis Y phase cell wall. Based on amino acid sequence, P. brasiliensis Agn1p, groups within the family 71 of fungal glycoside hydrolases (GH-71), showing similar biochemical characteristics to other members of this family. Also based on amino acid sequence alignments, we propose a subdivision of fungal GH-71 into at least five groups, for which specific conserved sequences can be identified.
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Affiliation(s)
- Héctor Villalobos-Duno
- Centro de Microbiología y Biología Celular, Instituto Venezolano de Investigaciones Científicas, Caracas, Venezuela
| | - Gioconda San-Blas
- Centro de Microbiología y Biología Celular, Instituto Venezolano de Investigaciones Científicas, Caracas, Venezuela
| | - Maryan Paulinkevicius
- Centro de Microbiología y Biología Celular, Instituto Venezolano de Investigaciones Científicas, Caracas, Venezuela
| | - Yolanda Sánchez-Martín
- Instituto de Biología funcional y Genómica and Departamento de Microbiología y Genética, Universidad de Salamanca, Salamanca, Spain
| | - Gustavo Nino-Vega
- Centro de Microbiología y Biología Celular, Instituto Venezolano de Investigaciones Científicas, Caracas, Venezuela
- * E-mail:
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Sharifmoghadam MR, Curto MÁ, Hoya M, de León N, Martin-Garcia R, Doncel C, Valdivieso MH. The integrity of the cytokinesis machinery under stress conditions requires the glucan synthase Bgs1p and its regulator Cfh3p. PLoS One 2012; 7:e42726. [PMID: 22905165 PMCID: PMC3419747 DOI: 10.1371/journal.pone.0042726] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Accepted: 07/10/2012] [Indexed: 12/29/2022] Open
Abstract
In yeast, cytokinesis requires coordination between nuclear division, acto-myosin ring contraction, and septum synthesis. We studied the role of the Schizosaccharomyces pombe Bgs1p and Cfh3p proteins during cytokinesis under stress conditions. Cfh3p formed a ring in the septal area that contracted during mitosis; Cfh3p colocalized and co-immunoprecipitated with Cdc15p, showing that Cfh3p interacted with the contractile acto-myosin ring. In a wild-type strain, a significant number of contractile rings collapsed under stress conditions and this number increased dramatically in the cfh3Δ, bgs1cps1-191, and cfh3Δ bgs1/cps1-191. Our results show that after osmotic shock Cfh3p is essential for the stability of the (1,3) glucan synthase Bgs1p in the septal area, but not at the cell poles. Finally, cells adapted to stress; they repaired their contractile rings and re-localized Bgs1p to the cell surface some time after osmotic shock. A detailed analysis of the cytokinesis machinery in the presence of KCl revealed that the actomyosin ring collapsed before Bgs1p was internalized, and that it was repaired before Bgs1p re-localized to the cell surface. In the cfh3Δ, bgs1/cps1-191, and cfh3Δ bgs1/cps1-191 mutants, which have reduced glucan synthesis, the damage produced to the ring had stronger consequences, suggesting that an intact primary septum contributes to ring stability. The results show that the contractile actomyosin ring is very sensitive to stress, and that cells have efficient mechanisms to remedy the damage produced in this structure.
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Affiliation(s)
- Mohammad Reza Sharifmoghadam
- Departamento de Microbiología y Genética/Instituto de Biología Funcional y Genómica, Universidad de Salamanca/Consejo Superior de Investigaciones Científicas, Salamanca, Spain
- Faculty of Veterinary Medicine, University of Zabol, Zabol, Sistan and Baluchestan, Iran
| | - M.-Ángeles Curto
- Departamento de Microbiología y Genética/Instituto de Biología Funcional y Genómica, Universidad de Salamanca/Consejo Superior de Investigaciones Científicas, Salamanca, Spain
| | - Marta Hoya
- Departamento de Microbiología y Genética/Instituto de Biología Funcional y Genómica, Universidad de Salamanca/Consejo Superior de Investigaciones Científicas, Salamanca, Spain
| | - Nagore de León
- Departamento de Microbiología y Genética/Instituto de Biología Funcional y Genómica, Universidad de Salamanca/Consejo Superior de Investigaciones Científicas, Salamanca, Spain
| | - Rebeca Martin-Garcia
- Departamento de Microbiología y Genética/Instituto de Biología Funcional y Genómica, Universidad de Salamanca/Consejo Superior de Investigaciones Científicas, Salamanca, Spain
| | - Cristina Doncel
- Departamento de Microbiología y Genética/Instituto de Biología Funcional y Genómica, Universidad de Salamanca/Consejo Superior de Investigaciones Científicas, Salamanca, Spain
| | - M.-Henar Valdivieso
- Departamento de Microbiología y Genética/Instituto de Biología Funcional y Genómica, Universidad de Salamanca/Consejo Superior de Investigaciones Científicas, Salamanca, Spain
- * E-mail:
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Hartl L, Gastebois A, Aimanianda V, Latgé JP. Characterization of the GPI-anchored endo β-1,3-glucanase Eng2 of Aspergillus fumigatus. Fungal Genet Biol 2010; 48:185-91. [PMID: 20619350 PMCID: PMC3092853 DOI: 10.1016/j.fgb.2010.06.011] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2010] [Revised: 06/18/2010] [Accepted: 06/18/2010] [Indexed: 11/15/2022]
Abstract
A GPI-anchored endo β-1,3-glucanase of Aspergillus fumigatus was characterized. The enzyme encoded by ENG2 (AFUA_2g14360) belongs to the glycoside hydrolase family 16 (GH16). The activity was characterized using a recombinant protein produced by Pichiapastoris. The recombinant enzyme preferentially acts on soluble β-1,3-glucans. Enzymatic analysis of the endoglucanase activity using Carboxymethyl-Curdlan-Remazol Brilliant Blue (CM-Curdlan-RBB) as a substrate revealed a wide temperature optimum of 24-40°C, a pH optimum of 5.0-6.5 and a K(m) of 0.8 mg ml(-1). HPAEC analysis of the products formed by Eng2 when acting on different oligo-β-1,3-glucans confirmed the predicted endoglucanase activity and also revealed a transferase activity for oligosaccharides of a low degree of polymerization. The growth phenotype of the Afeng2 mutant was identical to that of the wt strain.
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Affiliation(s)
- Lukas Hartl
- Unité des Aspergillus, Département de Parasitologie et Mycologie, Institut Pasteur, 25 rue du Docteur Roux, 75724 Paris cedex 15, France
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Roncero C, Sánchez Y. Cell separation and the maintenance of cell integrity during cytokinesis in yeast: the assembly of a septum. Yeast 2010; 27:521-30. [DOI: 10.1002/yea.1779] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
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30
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The inhibitory effects of mushroom extracts on sucrose-dependent oral biofilm formation. Appl Microbiol Biotechnol 2009; 86:615-23. [DOI: 10.1007/s00253-009-2323-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2009] [Revised: 10/14/2009] [Accepted: 10/19/2009] [Indexed: 10/20/2022]
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31
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Miklos I, Ludanyi K, Sipiczki M. The pleiotropic cell separation mutation spl1-1 is a nucleotide substitution in the internal promoter of the proline tRNACGG gene of Schizosaccharomyces pombe. Curr Genet 2009; 55:511-20. [PMID: 19636559 DOI: 10.1007/s00294-009-0262-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2009] [Revised: 07/06/2009] [Accepted: 07/09/2009] [Indexed: 11/25/2022]
Abstract
spl1-1 was originally identified as a spontaneous mutation genetically interacting with sep1-1 and cdc4-8 in producing multinucleate syncytia. This study shows that it is allelic with the proline-tRNA(CGG) gene SPATRNAPRO.02. Its nucleotide sequence contains a C-->T substitution in the region corresponding to the B-box of the putative intragenic promoter and the TpsiC loop of the mature tRNA. The substitution drastically reduces the transcription efficiency of the gene and pleiotropically affects numerous cellular processes. spl1-1 cells are temperature sensitive, osmosensitive, bend at higher temperatures, have extended G2 phase and are defective in cell separation (septum cleavage). The proline-tRNA(TGG) gene SPATRNAPRO.01 can partially suppress the spl1-1 mutation when introduced into the cells on a multicopy plasmid. The effect of a mutation in a tRNA gene on cell separation brings a new element into the complexity of the regulation of cell division and its co-ordination with other cellular processes in Schizosaccharomyces pombe.
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Affiliation(s)
- Ida Miklos
- Department of Genetics and Applied Microbiology, University of Debrecen, P.O. Box 56, 4010, Debrecen, Hungary
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32
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{beta}-glucanase Eng2 is required for ascus wall endolysis after sporulation in the fission yeast Schizosaccharomyces pombe. EUKARYOTIC CELL 2009; 8:1278-86. [PMID: 19542306 DOI: 10.1128/ec.00148-09] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Meiosis is the developmental program by which sexually reproducing diploid organisms generate haploid gametes. In yeast, meiosis is followed by spore morphogenesis. When Schizosaccharomyces pombe diploid cells undergo meiosis, they differentiate into asci containing four haploid ascospores that are highly resistant to environmental stress. The formation of the ascospore wall requires the activity of several enzymes involved in the biosynthesis and modification of its components, such as alpha- and beta-glucan synthases. Once the spores are completely mature, the wall of the ascus undergoes an endolytic process that results in the release of ascospores from the ascus, allowing their dispersal into the environment. This process requires the activity of the endo-alpha-1,3-glucanase Agn2. Here, we focus on the characterization of the endo-beta-1,3-glucanase Eng2, which is also required for ascospore release from the ascus. Although Eng2 is present during the mitotic cycle, the protein accumulates after meiosis II. The expression of eng2(+) is required for the efficient release of ascospores, as shown by placing eng2(+) under the control of a repressible promoter. Furthermore, a point mutation that destroys the catalytic activity of the protein results in a phenotype similar to that of the mutant strain. Finally, we demonstrate that exogenous addition of purified Eng2 releases the ascospores from asci generated by an eng2Delta mutant. We propose that Eng2 would act together with Agn2 to completely hydrolyze the ascus wall, thereby assisting in the release of ascospores in S. pombe.
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33
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Gastebois A, Clavaud C, Aimanianda V, Latgé JP. Aspergillus fumigatus: cell wall polysaccharides, their biosynthesis and organization. Future Microbiol 2009; 4:583-95. [DOI: 10.2217/fmb.09.29] [Citation(s) in RCA: 123] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Aspergillus fumigatus is the most prevalent thermophilic inhabitants of decaying vegetation and one of the most important human opportunistic fungal pathogens. Like other fungi, A. fumigatus cells are covered by a cell wall, which is both a protective, rigid exoskeleton and a dynamic structure, undergoing constant modification depending on its environment. The cell wall, in the majority of fungi, is composed of polysaccharides, and understanding the biochemical organization and biogenesis of an A. fumigatus cell wall is essential as this envelop is continuously in contact with the environment/host cell and acts as a sieve and reservoir for molecules, such as enzymes and toxins that play an active role during infection. This article is intended to give an overview of the biosynthesis of constituent cell wall polysaccharides and their postsynthetic modification in A. fumigatus, it also discusses the antifungal drugs that affect cell wall polysaccharide biosynthesis.
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Affiliation(s)
- Amandine Gastebois
- Unite des Aspergillus, Institut Pasteur, 25–28 rue du Docteur Roux, 75724, Paris, cedex 15, France
| | - Cécile Clavaud
- Unite des Aspergillus, Institut Pasteur, 25–28 rue du Docteur Roux, 75724, Paris, cedex 15, France
| | - Vishukumar Aimanianda
- Unite des Aspergillus, Institut Pasteur, 25–28 rue du Docteur Roux, 75724, Paris, cedex 15, France
| | - Jean-Paul Latgé
- Unite des Aspergillus, Institut Pasteur, 25–28 rue du Docteur Roux, 75724, Paris, cedex 15, France
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Martín-Cuadrado AB, Encinar del Dedo J, de Medina-Redondo M, Fontaine T, del Rey F, Latgé JP, Vázquez de Aldana CR. The Schizosaccharomyces pombe endo-1,3-beta-glucanase Eng1 contains a novel carbohydrate binding module required for septum localization. Mol Microbiol 2008; 69:188-200. [PMID: 18466295 DOI: 10.1111/j.1365-2958.2008.06275.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cell separation in Schizosaccharomyces pombe is achieved through the concerted action of the Eng1 endo-beta-1,3-glucanase and the Agn1 endo-alpha-1,3-glucanase, which are transported to the septum and localize to a ring-like structure that surrounds the septum. Correct localization of these hydrolases requires the presence of both the septins and the exocyst. In this work, we show that the glucanase Eng1 contains a region at the C-terminus that acts as a carbohydrate-binding module (CBM) and that it is not present in other members of glycoside hydrolases family 81 (GH81). In vitro, the purified CBM has affinity for beta-1,3-glucan chains with a minimum degree of polymerization of 30 glucose units. Deletion of the CBM results in a protein that is largely defective in complementing the separation defect of eng1Delta mutants. This defect is due to a reduction in the catalytic activity against insoluble substrates and to a defect in targeting of Eng1 to the septum, as the truncated protein localizes to the lateral cell wall of the cell. Thus, the targeting of Eng1 to the primary septum requires not only trans-factors (septins and the exocyst complex) but also a cis-element localized to the C-terminus of the protein.
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Affiliation(s)
- Ana Belén Martín-Cuadrado
- Instituto de Microbiología Bioquímica, Dpto. Microbiología y Genética, CSIC/Universidad de Salamanca, Campus Miguel de Unamuno 37007, Salamanca, Spain
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35
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Biochemical and molecular characterization of a novel type of Mutanase from Paenibacillus sp. strain RM1: identification of its mutan-binding domain, essential for degradation of Streptococcus mutans biofilms. Appl Environ Microbiol 2008; 74:2759-65. [PMID: 18326674 DOI: 10.1128/aem.02332-07] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A novel type of mutanase (termed mutanase RM1) was isolated from Paenibacillus sp. strain RM1. The purified enzyme specifically hydrolyzed alpha-1,3-glucan (mutan) and effectively degraded biofilms formed by Streptococcus mutans, a major etiologic agent in the progression of dental caries, even following brief incubation. The nucleotide sequence of the gene for this protein contains a 3,873-bp open reading frame encoding 1,291 amino acids with a calculated molecular mass of 135 kDa. The protein contains two major domains, the N-terminal domain (277 residues) and the C-terminal domain (937 residues), separated by a characteristic sequence composed of proline and threonine repeats. The characterization of the recombinant proteins for each domain which were expressed in Escherichia coli demonstrated that the N-terminal domain had strong mutan-binding activity but no mutanase activity whereas the C-terminal domain was responsible for mutanase activity but had mutan-binding activity significantly lower than that of the intact protein. Importantly, the biofilm-degrading activity observed with the intact protein was not exhibited by either domain alone or in combination with the other. Therefore, these results indicate that the structural integrity of mutanase RM1 containing the N-terminal mutan-binding domain is required for the biofilm-degrading activity.
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36
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Ge W, Balasubramanian MK. Pxl1p, a paxillin-related protein, stabilizes the actomyosin ring during cytokinesis in fission yeast. Mol Biol Cell 2008; 19:1680-92. [PMID: 18272786 DOI: 10.1091/mbc.e07-07-0715] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Paxillins are a family of conserved LIM domain-containing proteins that play important roles in the function and integrity of the actin cytoskeleton. Although paxillins have been extensively characterized by cell biological and biochemical approaches, genetic studies are relatively scarce. Here, we identify and characterize a paxillin-related protein Pxl1p in the fission yeast Schizosaccharomyces pombe. Pxl1p is a component of the fission yeast actomyosin ring, a structure that is essential for cytokinesis. Cells deleted for pxl1 display a novel phenotype characterized by a splitting of the actomyosin ring in late anaphase, leading to the formation of two rings of which only one undergoes constriction. In addition, the rate of actomyosin ring constriction is slower in the absence of Pxl1p. pxl1Delta mutants display strong genetic interactions with mutants defective in IQGAP-related protein Rng2p and mutants defective in components of the fission yeast type II myosin machinery. Collectively, these results suggest that Pxl1p might cooperate with type II myosin and Rng2p-IQGAP to regulate actomyosin ring constriction as well as to maintain its integrity during constriction.
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Affiliation(s)
- Wanzhong Ge
- Cell Division Laboratory, Temasek Life Sciences Laboratory and the Department of Biological Sciences, National University of Singapore, Singapore
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37
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Pinar M, Coll PM, Rincón SA, Pérez P. Schizosaccharomyces pombe Pxl1 is a paxillin homologue that modulates Rho1 activity and participates in cytokinesis. Mol Biol Cell 2008; 19:1727-38. [PMID: 18256290 DOI: 10.1091/mbc.e07-07-0718] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Schizosaccharomyces pombe Rho GTPases regulate actin cytoskeleton organization and cell integrity. We studied the fission yeast gene SPBC4F6.12 based on its ability to suppress the thermosensitivity of cdc42-1625 mutant strain. This gene, named pxl1(+), encodes a protein with three LIM domains that is similar to paxillin. Pxl1 does not interact with Cdc42 but it interacts with Rho1, and it negatively regulates this GTPase. Fission yeast Pxl1 forms a contractile ring in the cell division region and deletion of pxl1(+) causes a delay in cell-cell separation, suggesting that it has a function in cytokinesis. Pxl1 N-terminal region is required and sufficient for its localization to the medial ring, whereas the LIM domains are necessary for its function. Pxl1 localization requires actin polymerization and the actomyosin ring, but it is independent of the septation initiation network (SIN) function. Moreover, Pxl1 colocalizes and interacts with Myo2, and Cdc15, suggesting that it is part of the actomyosin ring. Here, we show that in cells lacking Pxl1, the myosin ring is not correctly assembled and that actomyosin ring contraction is delayed. Together, these data suggest that Pxl1 modulates Rho1 GTPase signaling and plays a role in the formation and contraction of the actomyosin ring during cytokinesis.
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Affiliation(s)
- Mario Pinar
- Instituto de Microbiología Bioquímica, Consejo Superior de Investigaciones Científicas/Departamento de Microbiología y Genética, Universidad de Salamanca, Edificio Departamental, 37007 Salamanca, Spain
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38
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Coll PM, Rincon SA, Izquierdo RA, Perez P. Hob3p, the fission yeast ortholog of human BIN3, localizes Cdc42p to the division site and regulates cytokinesis. EMBO J 2007; 26:1865-77. [PMID: 17363901 PMCID: PMC1847667 DOI: 10.1038/sj.emboj.7601641] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2007] [Accepted: 02/14/2007] [Indexed: 12/20/2022] Open
Abstract
Cdc42 GTPase is required for polarization in eukaryotic cells, but its spatial regulation is poorly understood. In Schizosaccharomyces pombe, Cdc42p is activated by Scd1p and Gef1p, two guanine-nucleotide exchange factors. Two-hybrid screening identified Hob3p as a Gef1p binding partner. Hob3p is a BAR domain-containing protein ortholog of human Bin3. Hob3p also interacts directly with Cdc42p independently of Gef1p. Hob3p, Cdc42p and Gef1p form a complex, and Hob3p facilitates Gef1p-Cdc42p interaction and activation. Hob3p forms a ring in the division area, similar to that of Gef1p. This localization requires actin polymerization and Cdc15p but is independent of the septation initiation network. Hob3p is required for the concentration of Cdc42p to the division area. The actomyosin ring contraction is slower in hob3Delta than in wild-type cells, and this contributes to its cytokinesis defect. Moreover, this report extends previous evidence that human Bin3 suppresses the cytokinesis phenotype of hob3Delta cells, showing that Bin3 can partially recover the GTP-Cdc42p level and its localization. These results suggest that Hob3p is required to recruit and activate Cdc42p at the cell division site and that this function might be conserved in other eukaryotes.
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Affiliation(s)
- Pedro M Coll
- Consejo Superior de Investigaciones Científicas (CSIC)/Departamento de Microbiología y Genética, Instituto de Microbiología Bioquímica, Universidad de Salamanca, Edificio Departamental, Salamanca 37007, Spain
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Jin QW, Zhou M, Bimbo A, Balasubramanian MK, McCollum D. A role for the septation initiation network in septum assembly revealed by genetic analysis of sid2-250 suppressors. Genetics 2006; 172:2101-12. [PMID: 16415366 PMCID: PMC1456390 DOI: 10.1534/genetics.105.050955] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
In the fission yeast Schizosaccharomyces pombe the septation initiation network (SIN) is required for stabilization of the actomyosin ring in late mitosis as well as for ring constriction and septum deposition. In a genetic screen for suppressors of the SIN mutant sid2-250, we isolated a mutation, ace2-35, in the transcription factor Ace2p. Both ace2Delta and ace2-35 show defects in cell separation, and both can rescue the growth defects of some SIN mutants at low restrictive temperatures, where the SIN single mutants lyse at the time of cytokinesis. By detailed analysis of the formation and constriction of the actomyosin ring and septum in the sid2-250 mutant at low restrictive temperatures, we show that the lysis phenotype of the sid2-250 mutant is likely due to a weak cell wall and septum combined with enzymatic activity of septum-degrading enzymes. Consistent with the recent findings that Ace2p controls transcription of genes involved in cell separation, we show that disruption of some of these genes can also rescue sid2-250 mutants. Consistent with SIN mutants having defects in septum formation, many SIN mutants can be rescued at the low restrictive temperature by the osmotic stabilizer sorbitol. The small GTPase Rho1 is known to promote cell wall formation, and we find that Rho1p expressed from a multi-copy plasmid can also rescue sid2-250 at the low restrictive temperature. Together these results suggest that the SIN has a role in promoting proper cell wall formation at the division septa.
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Affiliation(s)
- Quan-Wen Jin
- Department of Molecular Genetics and Microbiology, and Program in Cell Dynamics, University of Massachusetts Medical School, Worcester 01605, USA
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40
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Current awareness on yeast. Yeast 2006. [DOI: 10.1002/yea.1172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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41
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Santos B, Martín-Cuadrado AB, Vázquez de Aldana CR, del Rey F, Pérez P. Rho4 GTPase is involved in secretion of glucanases during fission yeast cytokinesis. EUKARYOTIC CELL 2005; 4:1639-45. [PMID: 16215171 PMCID: PMC1265894 DOI: 10.1128/ec.4.10.1639-1645.2005] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Rho GTPases are regulators of signaling pathways that control actin organization and cell polarity processes in all eukaryotic cells. In Schizosaccharomyces pombe, Rho4p is involved in the regulation of septum degradation during cytokinesis. Here we show that Rho4p participates in the secretion of the glucanases Eng1p and Agn1p, which are responsible for the septum degradation. First, eng1+ or agn1+ overexpression suppressed the rho4delta multiseptation phenotype, and simultaneous overproduction of Rho4p and Eng1p or of Rho4p and Agn1p caused a dramatic lysis. Second, Rho4p was not necessary for Eng1p-mediated glucanase activity as measured in cell extracts; however, rho4delta cells have a lower level of (1,3)-beta-D-glucanase activity in the culture medium. Additionally, Eng1- or Agn1-green fluorescent protein did not properly localize to the septum in rho4delta cells grown at 37 degrees C. There was a decreased amount of these enzymes in the cell wall and in the culture medium of rho4delta cells at 37 degrees C. These results provide evidence that Rho4p is involved in the regulation of Eng1p and Agn1p secretion during cytokinesis.
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Affiliation(s)
- Beatriz Santos
- Instituto Microbiología-Bioquímica, Departamento de Microbiología-Genética, Consejo Superior de Investigaciones Científicas/Universidad de Salamanca, Campus Unamuno, 37007 Salamanca, Spain.
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