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The Regulatory Role of the Aspergillus flavus Core Retromer Complex in Aflatoxin Metabolism. J Biol Chem 2022; 298:102120. [PMID: 35697069 PMCID: PMC9283945 DOI: 10.1016/j.jbc.2022.102120] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 05/25/2022] [Accepted: 05/26/2022] [Indexed: 11/23/2022] Open
Abstract
Aflatoxins are a series of highly toxic and carcinogenic secondary metabolites that are synthesized by Aspergillus species. The degradation of aflatoxin enzymes is an important regulatory mechanism which modulates mycotoxin producing. The retromer complex is responsible for the retrograde transport of specific biomolecules and the vacuolar fusion in the intracellular transport. Late endosomal-associated GTPase (Rab7) has been shown to be a downstream effector protein of the retromer complex. A deficiency in the retromer complex or Rab7 results in several cellular trafficking problems in yeast and humans, like protein abnormal accumulation. However, whether retromer dysfunction is involved in aflatoxin synthesis remains unclear. Here, we report that the core retromer complex, which comprises three vacuolar protein sorting-associated proteins (AflVps26-AflVps29-AflVps35), is essential for the development of dormant and resistant fungal forms such as conidia (asexual reproductive spore) and sclerotia (hardened fungal mycelium), as well as aflatoxin production and pathogenicity, in Aspergillus flavus. In particular, we show the AflVps26-AflVps29-AflVps35 complex is negatively correlated with aflatoxin exportation. Structural simulation, site-specific mutagenesis, and coimmunoprecipitation experiments showed that interactions among AflVps26, AflVps29, and AflVps35 played crucial roles in the retromer complex executing its core functions. We further found an intrinsic connection between AflRab7 and the retromer involved in vesicle-vacuole fusion, which in turn affected the accumulation of aflatoxin synthesis-associated enzymes, suggesting that they work together to regulate the production of toxins. Overall, these results provide mechanistic insights that contribute to our understanding of the regulatory role of the core retromer complex in aflatoxin metabolism.
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2
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Ohtsuka H, Imada K, Shimasaki T, Aiba H. Sporulation: A response to starvation in the fission yeast Schizosaccharomyces pombe. Microbiologyopen 2022; 11:e1303. [PMID: 35765188 PMCID: PMC9214231 DOI: 10.1002/mbo3.1303] [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: 04/13/2022] [Revised: 06/08/2022] [Accepted: 06/08/2022] [Indexed: 12/02/2022] Open
Abstract
The fission yeast Schizosaccharomyces pombe employs two main strategies to adapt to the environment and survive when starved for nutrients. The strategies employ sporulation via sexual differentiation and extension of the chronological lifespan. When a cell is exposed to nutrient starvation in the presence of a cell of the opposite sex, the cells undergo fusion through conjugation and sporulation through meiosis. S. pombe spores are highly resistant to diverse stresses and may survive for a very long time. In this minireview, among the various sexual differentiation processes induced by starvation, we focused on and summarized the findings of the molecular mechanisms of spore formation in fission yeast. Furthermore, comparative measurements of the chronological lifespan of stationary phase cells and G0 cells and the survival period of spore cells revealed that the spore cells survived for a long period, indicating the presence of an effective mechanism for survival. Currently, many molecules involved in sporulation and their functions are being discovered; however, our understanding of these is not complete. Further understanding of spores may not only deepen our comprehension of sexual differentiation but may also provide hints for sustaining life.
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Affiliation(s)
- Hokuto Ohtsuka
- Laboratory of Molecular Microbiology, Department of Basic Medicinal Sciences, Graduate School of Pharmaceutical Sciences, Nagoya University, Chikusa-ku, Nagoya, Japan
| | - Kazuki Imada
- Department of Chemistry and Biochemistry, National Institute of Technology (KOSEN), Suzuka College, Suzuka, Japan.,Department of Biology, Graduate School of Science, Osaka City University, Sumiyoshi-ku, Osaka, Japan
| | - Takafumi Shimasaki
- Laboratory of Molecular Microbiology, Department of Basic Medicinal Sciences, Graduate School of Pharmaceutical Sciences, Nagoya University, Chikusa-ku, Nagoya, Japan
| | - Hirofumi Aiba
- Laboratory of Molecular Microbiology, Department of Basic Medicinal Sciences, Graduate School of Pharmaceutical Sciences, Nagoya University, Chikusa-ku, Nagoya, Japan
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3
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Zhang B, Teraguchi E, Imada K, Tahara YO, Nakamura S, Miyata M, Kagiwada S, Nakamura T. The Fission Yeast RNA-Binding Protein Meu5 Is Involved in Outer Forespore Membrane Breakdown during Spore Formation. J Fungi (Basel) 2020; 6:jof6040284. [PMID: 33202882 PMCID: PMC7712723 DOI: 10.3390/jof6040284] [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: 10/26/2020] [Revised: 11/09/2020] [Accepted: 11/11/2020] [Indexed: 11/16/2022] Open
Abstract
In Schizosaccharomyces pombe, the spore wall confers strong resistance against external stress. During meiosis II, the double-layered intracellular forespore membrane (FSM) forms de novo and encapsulates the nucleus. Eventually, the inner FSM layer becomes the plasma membrane of the spore, while the outer layer breaks down. However, the molecular mechanism and biological significance of this membrane breakdown remain unknown. Here, by genetic investigation of an S. pombe mutant (E22) with normal prespore formation but abnormal spores, we showed that Meu5, an RNA-binding protein known to bind to and stabilize more than 80 transcripts, is involved in this process. We confirmed that the E22 mutant does not produce Meu5 protein, while overexpression of meu5+ in E22 restores the sporulation defect. Furthermore, electron microscopy revealed that the outer membrane of the FSM persisted in meu5∆ spores. Investigation of the target genes of meu5+ showed that a mutant of cyc1+ encoding cytochrome c also showed a severe defect in outer FSM breakdown. Lastly, we determined that outer FSM breakdown occurs coincident with or after formation of the outermost Isp3 layer of the spore wall. Collectively, our data provide novel insights into the molecular mechanism of spore formation.
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Affiliation(s)
- Bowen Zhang
- Department of Biology, Graduate School of Science, Osaka City University, Sumiyoshi-ku, Osaka 558-8585, Japan; (B.Z.); (E.T.); (K.I.); (Y.O.T.); (M.M.)
| | - Erika Teraguchi
- Department of Biology, Graduate School of Science, Osaka City University, Sumiyoshi-ku, Osaka 558-8585, Japan; (B.Z.); (E.T.); (K.I.); (Y.O.T.); (M.M.)
| | - Kazuki Imada
- Department of Biology, Graduate School of Science, Osaka City University, Sumiyoshi-ku, Osaka 558-8585, Japan; (B.Z.); (E.T.); (K.I.); (Y.O.T.); (M.M.)
- Department of Chemistry and Biochemistry, National Institute of Technology, Suzuka College, Suzuka 510-0294, Japan
| | - Yuhei O. Tahara
- Department of Biology, Graduate School of Science, Osaka City University, Sumiyoshi-ku, Osaka 558-8585, Japan; (B.Z.); (E.T.); (K.I.); (Y.O.T.); (M.M.)
- The OCU Advanced Research Institute for Natural Science and Technology (OCARINA), Osaka City University, Sumiyoshi-ku, Osaka 558-8585, Japan
| | - Shuko Nakamura
- Department of Biological Sciences, Faculty of Science, Nara Women’s University, Nara 630-8506, Japan; (S.N.); (S.K.)
| | - Makoto Miyata
- Department of Biology, Graduate School of Science, Osaka City University, Sumiyoshi-ku, Osaka 558-8585, Japan; (B.Z.); (E.T.); (K.I.); (Y.O.T.); (M.M.)
- The OCU Advanced Research Institute for Natural Science and Technology (OCARINA), Osaka City University, Sumiyoshi-ku, Osaka 558-8585, Japan
| | - Satoshi Kagiwada
- Department of Biological Sciences, Faculty of Science, Nara Women’s University, Nara 630-8506, Japan; (S.N.); (S.K.)
| | - Taro Nakamura
- Department of Biology, Graduate School of Science, Osaka City University, Sumiyoshi-ku, Osaka 558-8585, Japan; (B.Z.); (E.T.); (K.I.); (Y.O.T.); (M.M.)
- The OCU Advanced Research Institute for Natural Science and Technology (OCARINA), Osaka City University, Sumiyoshi-ku, Osaka 558-8585, Japan
- Correspondence:
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4
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A Cloning-Free Method for CRISPR/Cas9-Mediated Genome Editing in Fission Yeast. G3-GENES GENOMES GENETICS 2018; 8:2067-2077. [PMID: 29703785 PMCID: PMC5982833 DOI: 10.1534/g3.118.200164] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The CRISPR/Cas9 system, which relies on RNA‐guided DNA cleavage to induce site-specific DNA double-strand breaks, is a powerful tool for genome editing. This system has been successfully adapted for the fission yeast Schizosaccharomyces pombe by expressing Cas9 and the single-guide RNA (sgRNA) from a plasmid. In the procedures published to date, the cloning step that introduces a specific sgRNA target sequence into the plasmid is the most tedious and time-consuming. To increase the efficiency of applying the CRISPR/Cas9 system in fission yeast, we here developed a cloning-free procedure that uses gap repair in fission yeast cells to assemble two linear DNA fragments, a gapped Cas9-encoding plasmid and a PCR-amplified sgRNA insert, into a circular plasmid. Both fragments contain only a portion of the ura4 or bsdMX marker so that only the correctly assembled plasmid can confer uracil prototrophy or blasticidin resistance. We show that this gap-repair-based and cloning-free CRISPR/Cas9 procedure permits rapid and efficient point mutation knock-in, endogenous N-terminal tagging, and genomic sequence deletion in fission yeast.
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5
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Laviolette LA, Mermoud J, Calvo IA, Olson N, Boukhali M, Steinlein OK, Roider E, Sattler EC, Huang D, Teh BT, Motamedi M, Haas W, Iliopoulos O. Negative regulation of EGFR signalling by the human folliculin tumour suppressor protein. Nat Commun 2017; 8:15866. [PMID: 28656962 PMCID: PMC5493755 DOI: 10.1038/ncomms15866] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 05/09/2017] [Indexed: 02/01/2023] Open
Abstract
Germline mutations in the Folliculin (FLCN) tumour suppressor gene result in fibrofolliculomas, lung cysts and renal cancers, but the precise mechanisms of tumour suppression by FLCN remain elusive. Here we identify Rab7A, a small GTPase important for endocytic trafficking, as a novel FLCN interacting protein and demonstrate that FLCN acts as a Rab7A GTPase-activating protein. FLCN−/− cells display slower trafficking of epidermal growth factor receptors (EGFR) from early to late endosomes and enhanced activation of EGFR signalling upon ligand stimulation. Reintroduction of wild-type FLCN, but not tumour-associated FLCN mutants, suppresses EGFR signalling in a Rab7A-dependent manner. EGFR signalling is elevated in FLCN−/− tumours and the EGFR inhibitor afatinib suppresses the growth of human FLCN−/− cells as tumour xenografts. The functional interaction between FLCN and Rab7A appears conserved across species. Our work highlights a mechanism explaining, at least in part, the tumour suppressor function of FLCN. Folliculin is a known tumour suppressor but the molecular mechanisms behind this function are unclear. Here the authors show that Folliculin regulates EGFR signalling by modulating its Rab7a-dependent trafficking.
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Affiliation(s)
- Laura A Laviolette
- Center for Cancer Research, Massachusetts General Hospital Cancer Center and Harvard Medical School, Boston, Massachusetts 02139, USA
| | - Julien Mermoud
- Center for Cancer Research, Massachusetts General Hospital Cancer Center and Harvard Medical School, Boston, Massachusetts 02139, USA
| | - Isabel A Calvo
- Center for Cancer Research, Massachusetts General Hospital Cancer Center and Harvard Medical School, Boston, Massachusetts 02139, USA
| | - Nicholas Olson
- Center for Cancer Research, Massachusetts General Hospital Cancer Center and Harvard Medical School, Boston, Massachusetts 02139, USA
| | - Myriam Boukhali
- Center for Cancer Research, Massachusetts General Hospital Cancer Center and Harvard Medical School, Boston, Massachusetts 02139, USA
| | - Ortrud K Steinlein
- Institute of Human Genetics, University Hospital Munich, University of Munich, Munich 80336, Germany
| | - Elisabeth Roider
- Department of Dermatology and Allergology, University Hospital, Ludwig Maximilian University Munich, Munich D-80337, Germany
| | - Elke C Sattler
- Department of Dermatology and Allergology, University Hospital, Ludwig Maximilian University Munich, Munich D-80337, Germany
| | - Dachuan Huang
- Laboratory of Cancer Epigenome, Division of Medical Sciences, National Cancer Centre Singapore, Singapore 169610, Singapore.,Cancer and Stem Cell Biology Program, Duke-NUS Medical School, Singapore 169610, Singapore
| | - Bin Tean Teh
- Laboratory of Cancer Epigenome, Division of Medical Sciences, National Cancer Centre Singapore, Singapore 169610, Singapore.,Cancer and Stem Cell Biology Program, Duke-NUS Medical School, Singapore 169610, Singapore
| | - Mo Motamedi
- Center for Cancer Research, Massachusetts General Hospital Cancer Center and Harvard Medical School, Boston, Massachusetts 02139, USA
| | - Wilhelm Haas
- Center for Cancer Research, Massachusetts General Hospital Cancer Center and Harvard Medical School, Boston, Massachusetts 02139, USA
| | - Othon Iliopoulos
- Center for Cancer Research, Massachusetts General Hospital Cancer Center and Harvard Medical School, Boston, Massachusetts 02139, USA.,Division of Hematology-Oncology, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts 02114, USA
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6
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Zheng H, Zheng W, Wu C, Yang J, Xi Y, Xie Q, Zhao X, Deng X, Lu G, Li G, Ebbole D, Zhou J, Wang Z. Rab GTPases are essential for membrane trafficking-dependent growth and pathogenicity in Fusarium graminearum. Environ Microbiol 2015; 17:4580-99. [PMID: 26177389 DOI: 10.1111/1462-2920.12982] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2015] [Revised: 07/06/2015] [Accepted: 07/07/2015] [Indexed: 12/12/2022]
Abstract
Rab GTPases represent the largest subfamily of Ras-related small GTPases and regulate membrane trafficking. Vesicular transport is a general mechanism that governs intracellular membrane trafficking along the endocytic and exocytic pathways in all eukaryotic cells. Fusarium graminearum is a filamentous fungus and causes the devastating and economically important head blight of wheat and related species. The mechanism of vesicular transport is not well understood, and little is known about Rab GTPases in F. graminearum. In this study, we systematically characterized all eleven FgRabs by live cell imaging and genetic analysis. We find that FgRab51 and FgRab52 are important for the endocytosis, FgRab7 localizes to the vacuolar membrane and regulates the fusion of vacuoles and autophagosomes, and FgRab8 and FgRab11 are important for polarized growth and/or exocytosis. Furthermore, both endocytic and exocytic FgRabs are required for vegetative growth, conidiogenesis, sexual reproduction, as well as pathogenesis and deoxynivalenol metabolism in F. graminearum. Thus, we conclude that Rab GTPases are essential for membrane trafficking-dependent growth and pathogenicity in F. graminearum.
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Affiliation(s)
- Huawei Zheng
- Fujian Province Key Laboratory of Pathogenic Fungi and Mycotoxins, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China.,Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Wenhui Zheng
- Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Congxian Wu
- Fujian Province Key Laboratory of Pathogenic Fungi and Mycotoxins, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Jie Yang
- Institute of Forestry Protection, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Yang Xi
- Fujian Province Key Laboratory of Pathogenic Fungi and Mycotoxins, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Qiurong Xie
- Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Xu Zhao
- Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Xiaolong Deng
- Fujian Province Key Laboratory of Pathogenic Fungi and Mycotoxins, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Guodong Lu
- Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Guangpu Li
- Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry University, Fuzhou, China.,Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Daniel Ebbole
- Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry University, Fuzhou, China.,Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX, USA
| | - Jie Zhou
- Fujian Province Key Laboratory of Pathogenic Fungi and Mycotoxins, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China.,Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Zonghua Wang
- Fujian Province Key Laboratory of Pathogenic Fungi and Mycotoxins, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China.,Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry University, Fuzhou, China
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7
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Tsukamoto Y, Kagiwada S, Shimazu S, Takegawa K, Noguchi T, Miyamoto M. Coordinated regulation by two VPS9 domain-containing guanine nucleotide exchange factors in small GTPase Rab5 signaling pathways in fission yeast. Biochem Biophys Res Commun 2015; 458:802-9. [DOI: 10.1016/j.bbrc.2015.02.031] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Accepted: 02/06/2015] [Indexed: 12/11/2022]
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8
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Tsukamoto Y, Katayama C, Shinohara M, Shinohara A, Maekawa S, Miyamoto M. The small GTPase Rab5 homologue Ypt5 regulates cell morphology, sexual development, ion-stress response and vacuolar formation in fission yeast. Biochem Biophys Res Commun 2013; 441:867-72. [PMID: 24211211 DOI: 10.1016/j.bbrc.2013.10.158] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Accepted: 10/29/2013] [Indexed: 01/08/2023]
Abstract
Inner-membrane transport is critical to cell function. Rab family GTPases play an important role in vesicle transport. In mammalian cells, Rab5 is reported to be involved in the regulation of endosome formation, phagocytosis and chromosome alignment. Here, we examined the role of the fission yeast Rab5 homologue Ypt5 using a point mutant allele. Mutant cells displayed abnormal cell morphology, mating, sporulation, endocytosis, vacuole fusion and responses to ion stress. Our data strongly suggest that fission yeast Rab5 is involved in the regulation of various types of cellular functions.
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Affiliation(s)
- Yuta Tsukamoto
- Graduate School of Science, Kobe University, 1-1 Rokkodai-cho Nada, Kobe 657-8501, Japan
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9
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Kashiwazaki J, Yamasaki Y, Itadani A, Teraguchi E, Maeda Y, Shimoda C, Nakamura T. Endocytosis is essential for dynamic translocation of a syntaxin 1 orthologue during fission yeast meiosis. Mol Biol Cell 2011; 22:3658-70. [PMID: 21832151 PMCID: PMC3183020 DOI: 10.1091/mbc.e11-03-0255] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Fission yeast sporulation seems to accompany a dynamic alteration of membrane traffic pathways in which the destination of secretory vesicles changes from the plasma membrane to the developing spore membrane. Evidence shows that endocytosis is responsible for this alteration in traffic pathways via the relocalization of syntaxin 1. Syntaxin is a component of the target soluble N-ethylmaleimide–sensitive factor attachment protein receptor complex, which is responsible for fusion of membrane vesicles at the target membrane. The fission yeast syntaxin 1 orthologue Psy1 is essential for both vegetative growth and spore formation. During meiosis, Psy1 disappears from the plasma membrane (PM) and dramatically relocalizes on the nascent forespore membrane, which becomes the PM of the spore. Here we report the molecular details and biological significance of Psy1 relocalization. We find that, immediately after meiosis I, Psy1 is selectively internalized by endocytosis. In addition, a meiosis-specific signal induced by the transcription factor Mei4 seems to trigger this internalization. The internalization of many PM proteins is facilitated coincident with the initiation of meiosis, whereas Pma1, a P-type ATPase, persists on the PM even during the progression of meiosis II. Ergosterol on the PM is also important for the internalization of PM proteins in general during meiosis. We consider that during meiosis in Schizosaccharomyces pombe cells, the characteristics of endocytosis change, thereby facilitating internalization of Psy1 and accomplishing sporulation.
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Affiliation(s)
- Jun Kashiwazaki
- Department of Biology, Graduate School of Science, Osaka City University, Osaka 558-8585, Japan
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10
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Hosomi A, Nakase M, Takegawa K. Schizosaccharomyces pombe Pep12p is required for vacuolar protein transport and vacuolar homotypic fusion. J Biosci Bioeng 2011; 112:309-14. [PMID: 21757403 DOI: 10.1016/j.jbiosc.2011.06.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2011] [Revised: 06/14/2011] [Accepted: 06/18/2011] [Indexed: 10/18/2022]
Abstract
In eukaryotic cells, SNARE proteins are essential for intracellular vesicle trafficking. Several SNARE proteins are required for vacuolar protein transport and vacuolar biogenesis in Saccharomyces cerevisiae. Previously we demonstrated that one of the fission yeast SNARE proteins, Pep12p, is not required for vacuolar fusion process in Schizosaccharomyces pombe. We have re-examined the function of S. pombe Pep12p using the newly created pep12(+) deletion strain. Deletion of the fission yeast pep12(+) gene results in pleiotropic phenotypes consistent with the absence of normal vacuoles, including missorting of vacuolar carboxypeptidase Y-and various ion- and drug-sensitivities. GFP-Pep12 fusion protein is mostly localized at the vacuolar membrane and the prevacuolar compartment. The S. pombe pep12Δ mutation phenocopies that of vps33Δ, suggesting that both Pep12p and Vps33p act at the same membrane fusion step in S. pombe, and both mutations cause vacuolar deficiency.
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Affiliation(s)
- Akira Hosomi
- Department of Life Sciences, Kagawa University, Miki-cho, Kagawa 761-0795, Japan
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11
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Armstrong J. Yeast vacuoles: more than a model lysosome. Trends Cell Biol 2010; 20:580-5. [DOI: 10.1016/j.tcb.2010.06.010] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2009] [Revised: 06/30/2010] [Accepted: 06/30/2010] [Indexed: 10/19/2022]
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12
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Role of septins in the orientation of forespore membrane extension during sporulation in fission yeast. Mol Cell Biol 2010; 30:2057-74. [PMID: 20123972 DOI: 10.1128/mcb.01529-09] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
During yeast sporulation, a forespore membrane (FSM) initiates at each spindle-pole body and extends to form the spore envelope. We used Schizosaccharomyces pombe to investigate the role of septins during this process. During the prior conjugation of haploid cells, the four vegetatively expressed septins (Spn1, Spn2, Spn3, and Spn4) coassemble at the fusion site and are necessary for its normal morphogenesis. Sporulation involves a different set of four septins (Spn2, Spn5, Spn6, and the atypical Spn7) that does not include the core subunits of the vegetative septin complex. The four sporulation septins form a complex in vitro and colocalize interdependently to a ring-shaped structure along each FSM, and septin mutations result in disoriented FSM extension. The septins and the leading-edge proteins appear to function in parallel to orient FSM extension. Spn2 and Spn7 bind to phosphatidylinositol 4-phosphate [PtdIns(4)P] in vitro, and PtdIns(4)P is enriched in the FSMs, suggesting that septins bind to the FSMs via this lipid. Cells expressing a mutant Spn2 protein unable to bind PtdIns(4)P still form extended septin structures, but these structures fail to associate with the FSMs, which are frequently disoriented. Thus, septins appear to form a scaffold that helps to guide the oriented extension of the FSM.
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13
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Röthlisberger S, Jourdain I, Johnson C, Takegawa K, Hyams JS. The dynamin-related protein Vps1 regulates vacuole fission, fusion and tubulation in the fission yeast, Schizosaccharomyces pombe. Fungal Genet Biol 2009; 46:927-35. [PMID: 19643199 DOI: 10.1016/j.fgb.2009.07.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2009] [Revised: 07/13/2009] [Accepted: 07/19/2009] [Indexed: 01/07/2023]
Abstract
Fission yeast cells lacking the dynamin-related protein (DRP) Vps1 had smaller vacuoles with reduced capacity for both fusion and fission in response to hypotonic and hypertonic conditions respectively. vps1Delta cells showed normal vacuolar protein sorting, actin organisation and endocytosis. Over-expression of vps1 transformed vacuoles from spherical to tubular. Tubule formation was enhanced in fission conditions and required the Rab protein Ypt7. Vacuole tubulation by Vps1 was more extensive in the absence of a second DRP, Dnm1. Both dnm1Delta and the double mutant vps1Delta dnm1Delta showed vacuole fission defects similar to that of vps1Delta. Over-expression of vps1 in dnm1Delta, or of dnm1 in vps1Delta failed to rescue this phenotype. Over-expression of dnm1 in wild-type cells, on the other hand, induced vacuole fission. Our results are consistent with a model of vacuole fission in which Vps1 creates a tubule of an appropriate diameter for subsequent scission by Dnm1.
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Affiliation(s)
- Sarah Röthlisberger
- Institute of Molecular Biosciences, Massey University, Private Bag 11222, Palmerston North, New Zealand
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14
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Kashiwazaki J, Iwaki T, Takegawa K, Shimoda C, Nakamura T. Two Fission Yeast Rab7 Homologs, Ypt7 and Ypt71, Play Antagonistic Roles in the Regulation of Vacuolar Morphology. Traffic 2009; 10:912-24. [DOI: 10.1111/j.1600-0854.2009.00907.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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15
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Ohtaka A, Okuzaki D, Nojima H. Mug27 is a meiosis-specific protein kinase that functions in fission yeast meiosis II and sporulation. J Cell Sci 2008; 121:1547-58. [PMID: 18411246 DOI: 10.1242/jcs.022830] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Several meiosis-specific proteins of Schizosaccharomyces pombe play essential roles in meiotic progression. We report here that a novel meiosis-specific protein kinase, Mug27 (also known as Ppk35), is required for proper spore formation. This kinase is expressed by the mug27(+) gene, which is abruptly transcribed after horsetail movement. This transcription is maintained until the second meiotic division. Green fluorescent protein (GFP)-tagged Mug27 appears at the start of prometaphase I, localizes to the spindle pole body (SPB) and then translocates to the forespore membrane (FSM) at late anaphase II. In the mug27Delta strain, smaller spores are produced compared with those of the mug27(+) strain. Moreover, spore viability was reduced by half or more compared with that of the mug27(+) strain. The protein-kinase activity of Mug27 appears to be important for its function: the putative kinase-dead Mug27 mutant had similar phenotypes to mug27Delta. Our results here indicate that the Mug27 kinase localizes at the SPB and regulates FSM formation and sporulation.
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Affiliation(s)
- Ayami Ohtaka
- Department of Molecular Genetics, Research Institute for Microbial Diseases, Osaka University, Suita City, Osaka, Japan
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Schizosaccharomyces pombe Sst4p, a conserved Vps27/Hrs homolog, functions downstream of phosphatidylinositol 3-kinase Pik3p to mediate proper spore formation. EUKARYOTIC CELL 2007; 6:2343-53. [PMID: 17951524 DOI: 10.1128/ec.00211-07] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Sporulation of the fission yeast Schizosaccharomyces pombe is a developmental process that generates gametes and that includes the formation of spore envelope precursors called the forespore membranes. Assembly and development of forespore membranes require vesicular trafficking from other intracellular membrane compartments. We have shown that phosphatidylinositol 3-kinase (PtdIns 3-kinase) is required for efficient and proper development of forespore membranes. The role of a FYVE domain protein, Sst4p, a homolog of Vps27p/Hrs, as a downstream factor for PtdIns 3-kinase in sporulation was investigated. sst4Delta asci formed spores with oval-shaped morphology and with reduced viability compared to that of the wild-type spores. The extension of forespore membranes was inefficient, and bubble-like structures emerged from the leading edges of the forespore membranes. Sst4p localization was examined using fluorescent protein fusions and was found to be adjacent to the forespore membranes during sporulation. The localization and function of Sst4p were dependent on its FYVE domain and on PtdIns 3-kinase. Sst4p colocalized and interacted with Hse1p, a homolog of Saccharomyces cerevisiae Hse1p and of mammalian STAM. Mutations in all three UIM domains of the Sst4p/Hse1p complex resulted in formation of spores with abnormal morphology. These results suggest that Sst4p is a downstream factor of PtdIns 3-kinase and functions in forespore membrane formation.
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Ye Y, Fujii M, Hirata A, Kawamukai M, Shimoda C, Nakamura T. Geranylgeranyl diphosphate synthase in fission yeast is a heteromer of farnesyl diphosphate synthase (FPS), Fps1, and an FPS-like protein, Spo9, essential for sporulation. Mol Biol Cell 2007; 18:3568-81. [PMID: 17596513 PMCID: PMC1951748 DOI: 10.1091/mbc.e07-02-0112] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Both farnesyl diphosphate synthase (FPS) and geranylgeranyl diphosphate synthase (GGPS) are key enzymes in the synthesis of various isoprenoid-containing compounds and proteins. Here, we describe two novel Schizosaccharomyces pombe genes, fps1(+) and spo9(+), whose products are similar to FPS in primary structure, but whose functions differ from one another. Fps1 is essential for vegetative growth, whereas, a spo9 null mutant exhibits temperature-sensitive growth. Expression of fps1(+), but not spo9(+), suppresses the lethality of a Saccharomyces cerevisiae FPS-deficient mutant and also restores ubiquinone synthesis in an Escherichia coli ispA mutant, which lacks FPS activity, indicating that S. pombe Fps1 in fact functions as an FPS. In contrast to a typical FPS gene, no apparent GGPS homologues have been found in the S. pombe genome. Interestingly, although neither fps1(+) nor spo9(+) expression alone in E. coli confers clear GGPS activity, coexpression of both genes induces such activity. Moreover, the GGPS activity is significantly reduced in the spo9 mutant. In addition, the spo9 mutation perturbs the membrane association of a geranylgeranylated protein, but not that of a farnesylated protein. Yeast two-hybrid and coimmunoprecipitation analyses indicate that Fps1 and Spo9 physically interact. Thus, neither Fps1 nor Spo9 alone functions as a GGPS, but the two proteins together form a complex with GGPS activity. Because spo9 was originally identified as a sporulation-deficient mutant, we show here that expansion of the forespore membrane is severely inhibited in spo9Delta cells. Electron microscopy revealed significant accumulation membrane vesicles in spo9Delta cells. We suggest that lack of GGPS activity in a spo9 mutant results in impaired protein prenylation in certain proteins responsible for secretory function, thereby inhibiting forespore membrane formation.
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Affiliation(s)
- Yanfang Ye
- *Department of Biology, Graduate School of Science, Osaka City University, Sumiyoshi-ku, Osaka 558-8585, Japan
| | - Makoto Fujii
- Department of Applied Bioscience and Biotechnology, Faculty of Life and Environmental Science, Shimane University, Matsue 690-8504, Japan
| | - Aiko Hirata
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo, Kashiwa, Chiba 277-8562, Japan; and
| | - Makoto Kawamukai
- Department of Applied Bioscience and Biotechnology, Faculty of Life and Environmental Science, Shimane University, Matsue 690-8504, Japan
| | - Chikashi Shimoda
- *Department of Biology, Graduate School of Science, Osaka City University, Sumiyoshi-ku, Osaka 558-8585, Japan
| | - Taro Nakamura
- *Department of Biology, Graduate School of Science, Osaka City University, Sumiyoshi-ku, Osaka 558-8585, Japan
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Dekker N, van Rijssel J, Distel B, Hochstenbach F. Role of the alpha-glucanase Agn2p in ascus-wall endolysis following sporulation in fission yeast. Yeast 2007; 24:279-88. [PMID: 17315266 DOI: 10.1002/yea.1464] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
During sporulation in the ascomyceteous fungus Schizosaccharomyces pombe, diploid cells undergo differentiation into asci containing four haploid ascospores, which are highly resistant to environmental stresses. Although the morphogenetic processes involved in ascospore formation have been studied extensively, little is known about the molecular mechanism that ensures the release of mature ascospores from the ascus, allowing their dispersal into the environment. Recently, we identified Agn2p as the paralogue of the characterized endo-(1,3)-alpha-glucanase Agn1p, and observed that asci deleted for agn2 are defective in ascospore dispersal. Here, we focus on the cellular and biochemical functions of Agn2p. By placing agn2 under the control of an inducible promoter, we show that expression of agn2 is required for the efficient release of ascospores from their asci. Furthermore, we characterize the enzyme activity of purified recombinant Agn2p and show that Agn2p, like Agn1p, is an endo-(1,3)-alpha-glucanase that produces predominantly (1,3)-alpha-glucan pentasaccharides. Finally, we demonstrate that exogenous addition of purified Agn2p liberated the ascospores from asci deleted for agn2. We propose that Agn2p participates in the endolysis of the ascus wall by hydrolysing its (1,3)-alpha-glucan, thereby assisting in the release of ascospores.
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Affiliation(s)
- Nick Dekker
- Department of Medical Biochemistry, Academic Medical Center, University of Amsterdam, Meibergdreef 15, 1105 AZ Amsterdam, The Netherlands
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Hamada M, Ohata I, Fujita KI, Usuki Y, Ogita A, Ishiguro J, Tanaka T. Inhibitory Activity of 1-Farnesylpyridinium on the Spatial Control over the Assembly of Cell Wall Polysaccharides in Schizosaccharomyces pombe. ACTA ACUST UNITED AC 2006; 140:851-9. [PMID: 17092950 DOI: 10.1093/jb/mvj218] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
The modes of actions of 1-farnesylpyridinium (FPy) on yeast cell growth were investigated on the basis of its effects on cell cycle progression, morphogenesis and the related events for construction of cell wall architecture in Schizosacchromyces pombe. FPy predominantly inhibited the growth of the yeast cells after various cycles of cell division so that cells were arrested at the phase of separation into daughter cells accompanying morphological changes to swollen spherical cells at 24 h of incubation. FPy-treated cells were osmotically stable but were susceptible to the lytic action of (1, 3) beta-D-glucanases, and characterized by serious damages to the cell wall architecture as represented by a rough and irregular surface outlook. The isolated cell wall fraction gave a similar hexose composition with or without FPy treatment, suggesting that FPy did not inhibit the synthesis of each cell wall polysaccharide. FPy was permissive for the extracellular accumulation of amorphous cell wall materials and septum development in protoplasts, but absolutely interfered with the following morphogenetic process for construction of the rod-shaped cell wall architecture. Our results suggest the inhibitory activity of FPy on the spatial control over the assembly of cell wall polysaccharides.
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Affiliation(s)
- Masahiro Hamada
- Graduate School of Science and Research Center for Urban Health and Sports, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585.
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Current awareness on yeast. Yeast 2006. [DOI: 10.1002/yea.1318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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