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Varela Salgado M, Adriaans IE, Touati SA, Ibanes S, Lai-Kee-Him J, Ancelin A, Cipelletti L, Picas L, Piatti S. Phosphorylation of the F-BAR protein Hof1 drives septin ring splitting in budding yeast. Nat Commun 2024; 15:3383. [PMID: 38649354 PMCID: PMC11035697 DOI: 10.1038/s41467-024-47709-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Accepted: 04/09/2024] [Indexed: 04/25/2024] Open
Abstract
A double septin ring accompanies cytokinesis in yeasts and mammalian cells. In budding yeast, reorganisation of the septin collar at the bud neck into a dynamic double ring is essential for actomyosin ring constriction and cytokinesis. Septin reorganisation requires the Mitotic Exit Network (MEN), a kinase cascade essential for cytokinesis. However, the effectors of MEN in this process are unknown. Here we identify the F-BAR protein Hof1 as a critical target of MEN in septin remodelling. Phospho-mimicking HOF1 mutant alleles overcome the inability of MEN mutants to undergo septin reorganisation by decreasing Hof1 binding to septins and facilitating its translocation to the actomyosin ring. Hof1-mediated septin rearrangement requires its F-BAR domain, suggesting that it may involve a local membrane remodelling that leads to septin reorganisation. In vitro Hof1 can induce the formation of intertwined septin bundles, while a phosphomimetic Hof1 protein has impaired septin-bundling activity. Altogether, our data indicate that Hof1 modulates septin architecture in distinct ways depending on its phosphorylation status.
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Affiliation(s)
- Maritzaida Varela Salgado
- CRBM (Centre de Recherche en Biologie cellulaire de Montpellier), University of Montpellier, CNRS UMR 5237, 34293, Montpellier, France
| | - Ingrid E Adriaans
- CRBM (Centre de Recherche en Biologie cellulaire de Montpellier), University of Montpellier, CNRS UMR 5237, 34293, Montpellier, France
| | - Sandra A Touati
- Université Paris Cité, CNRS, Institut Jacques Monod, 75013, Paris, France
| | - Sandy Ibanes
- CRBM (Centre de Recherche en Biologie cellulaire de Montpellier), University of Montpellier, CNRS UMR 5237, 34293, Montpellier, France
| | - Joséphine Lai-Kee-Him
- CBS (Centre de Biologie Structurale), University of Montpellier, CNRS UMR 5048, INSERM U 1054, 34090, Montpellier, France
| | - Aurélie Ancelin
- CBS (Centre de Biologie Structurale), University of Montpellier, CNRS UMR 5048, INSERM U 1054, 34090, Montpellier, France
| | - Luca Cipelletti
- L2C (Laboratoire Charles Coulomb), University of Montpellier, CNRS 34095, Montpellier, France
- IUF (Institut Universitaire de France, 75231, Paris, France
| | - Laura Picas
- IRIM (Institut de Recherche en Infectiologie de Montpellier), University of Montpellier, CNRS UMR 9004, 34293, Montpellier, France
| | - Simonetta Piatti
- CRBM (Centre de Recherche en Biologie cellulaire de Montpellier), University of Montpellier, CNRS UMR 5237, 34293, Montpellier, France.
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2
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Rossi AM, Bohnert KA, Gould KL. The fission yeast cytokinetic ring component Fic1 promotes septum formation. Biol Open 2023; 12:308901. [PMID: 37158439 PMCID: PMC10184318 DOI: 10.1242/bio.059957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Accepted: 04/19/2023] [Indexed: 05/10/2023] Open
Abstract
In Schizosaccharomyces pombe, septum formation is coordinated with cytokinetic ring constriction but the mechanisms linking these events are unclear. In this study, we explored the role of the cytokinetic ring component Fic1, first identified by its interaction with the F-BAR protein Cdc15, in septum formation. We found that the fic1 phospho-ablating mutant, fic1-2A, is a gain-of-function allele that suppresses myo2-E1, the temperature-sensitive allele of the essential type-II myosin, myo2. This suppression is achieved by the promotion of septum formation and required Fic1's interaction with the F-BAR proteins Cdc15 and Imp2. Additionally, we found that Fic1 interacts with Cyk3 and that this interaction was likewise required for Fic1's role in septum formation. Fic1, Cdc15, Imp2, and Cyk3 are the orthologs of the Saccharomyces cerevisiae ingression progression complex, which stimulates the chitin synthase Chs2 to promote primary septum formation. However, our findings indicate that Fic1 promotes septum formation and cell abscission independently of the S. pombe Chs2 ortholog. Thus, while similar complexes exist in the two yeasts that each promote septation, they appear to have different downstream effectors.
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Affiliation(s)
- Anthony M Rossi
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240, USA
| | - K Adam Bohnert
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240, USA
| | - Kathleen L Gould
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240, USA
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3
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Mamun MAA, Cao W, Nakamura S, Maruyama JI. Large-scale identification of genes involved in septal pore plugging in multicellular fungi. Nat Commun 2023; 14:1418. [PMID: 36932089 PMCID: PMC10023807 DOI: 10.1038/s41467-023-36925-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 02/23/2023] [Indexed: 03/19/2023] Open
Abstract
Multicellular filamentous fungi have septal pores that allow cytoplasmic exchange, and thus connectivity, between neighboring cells in the filament. Hyphal wounding and other stress conditions induce septal pore closure to minimize cytoplasmic loss. However, the composition of the septal pore and the mechanisms underlying its function are not well understood. Here, we set out to identify new septal components by determining the subcellular localization of 776 uncharacterized proteins in a multicellular ascomycete, Aspergillus oryzae. The set of 776 uncharacterized proteins was selected on the basis that their genes were present in the genomes of multicellular, septal pore-bearing ascomycetes (three Aspergillus species, in subdivision Pezizomycotina) and absent/divergent in the genomes of septal pore-lacking ascomycetes (yeasts). Upon determining their subcellular localization, 62 proteins were found to localize to the septum or septal pore. Deletion of the encoding genes revealed that 23 proteins are involved in regulating septal pore plugging upon hyphal wounding. Thus, this study determines the subcellular localization of many uncharacterized proteins in A. oryzae and, in particular, identifies a set of proteins involved in septal pore function.
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Affiliation(s)
| | - Wei Cao
- Research Center for Agricultural Information Technology, National Agriculture and Food Research Organization (NARO), Tsukuba, Ibaraki, Japan
| | - Shugo Nakamura
- Department of Information Networking for Innovation and Design, Faculty of Information Networking for Innovation and Design, Toyo University, Tokyo, Japan
| | - Jun-Ichi Maruyama
- Department of Biotechnology, The University of Tokyo, Tokyo, Japan.
- Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, Tokyo, Japan.
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4
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Rossi AM, Bohnert KA, Gould KL. The fission yeast cytokinetic ring component Fic1 promotes septum formation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.13.532462. [PMID: 36993237 PMCID: PMC10054984 DOI: 10.1101/2023.03.13.532462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
In Schizosaccharomyces pombe septum formation is coordinated with cytokinetic ring constriction but the mechanisms linking these events are unclear. In this study, we explored the role of the cytokinetic ring component Fic1, first identified by its interaction with the F-BAR protein Cdc15, in septum formation. We found that the fic1 phospho-ablating mutant, fic1-2A , is a gain-of-function allele that suppresses myo2-E1 , the temperature-sensitive allele of the essential type-II myosin, myo2 . This suppression is achieved by the promotion of septum formation and required Fic1's interaction with the F-BAR proteins Cdc15 and Imp2. Additionally, we found that Fic1 interacts with Cyk3 and that this interaction was likewise required for Fic1's role in septum formation. Fic1, Cdc15, Imp2, and Cyk3 are the orthologs of the Saccharomyces cerevisiae ingression progression complex, which stimulates the chitin synthase Chs2 to promote primary septum formation. However, our findings indicate that Fic1 promotes septum formation and cell abscission independently of the S. pombe Chs2 ortholog. Thus, while similar complexes exist in the two yeasts that each promote septation, they appear to have different downstream effectors. Summary Statement The S. pombe cytokinetic ring protein Fic1 promotes septum formation in a manner dependent on interactions with the cytokinetic ring components Cdc15, Imp2, and Cyk3.
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5
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Bellingham-Johnstun K, Commer B, Levesque B, Tyree ZL, Laplante C. Imp2p forms actin-dependent clusters and imparts stiffness to the contractile ring. Mol Biol Cell 2022; 33:ar145. [PMID: 36287824 PMCID: PMC9727792 DOI: 10.1091/mbc.e22-06-0221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The contractile ring must anchor to the plasma membrane and cell wall to transmit its tension. F-BAR domain containing proteins including Imp2p and Cdc15p in fission yeast are likely candidate anchoring proteins based on their mutant phenotypes. Cdc15p is a node component, links the actin bundle to the plasma membrane, recruits Bgs1p to the division plane, prevents contractile ring sliding, and contributes to the stiffness of the contractile ring. Less is known about Imp2p. We found that similarly to Cdc15p, Imp2p contributes to the stiffness of the contractile ring and assembles into protein clusters. Imp2p clusters contain approximately eight Imp2p dimers and depend on the actin network for their stability at the division plane. Importantly, Imp2p and Cdc15p reciprocally affect the amount of each other in the contractile ring, indicating that the two proteins influence each other during cytokinesis, which may partially explain their similar phenotypes.
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Affiliation(s)
| | - Blake Commer
- Department of Molecular Biomedical Sciences, North Carolina State University, Raleigh, NC 27607
| | - Brié Levesque
- Department of Molecular Biomedical Sciences, North Carolina State University, Raleigh, NC 27607
| | - Zoe L Tyree
- Department of Molecular Biomedical Sciences, North Carolina State University, Raleigh, NC 27607
| | - Caroline Laplante
- Department of Molecular Biomedical Sciences, North Carolina State University, Raleigh, NC 27607
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6
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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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7
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Kianfard Z, Cheung K, Rappaport D, Magalage SP, Sabatinos SA. Detecting Cell Cycle Stage and Progression in Fission Yeast, Schizosaccharomyces pombe. Methods Mol Biol 2022; 2579:235-246. [PMID: 36045211 DOI: 10.1007/978-1-0716-2736-5_18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
We have previously described methods to synchronize cultures of fission yeast, Schizosaccharomyces pombe. In this chapter, we provide methods to detect cell cycle stage in cells and populations of S. pombe. These protocols used fixed samples. First, we describe sample preparation for flow cytometry of bulk DNA content. This technique allows users to monitor progression of DNA replication and detect any perturbation during the synthesis (S) phase of the cell cycle. Second, we describe methods to stain nuclei and septa of fixed yeast cells, and monitor proportions of cell cycle stages within cultures. Together, these methods provide the ability to compare cell cycle progression or delay between cultures, making use of the powerful molecular genetics tool that is S. pombe.
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Affiliation(s)
- Zohreh Kianfard
- Molecular Science Program, Yeates School of Graduate Studies, Toronto Metropolitan University (formerly Ryerson University), Toronto, ON, Canada
| | - Kyle Cheung
- Molecular Science Program, Yeates School of Graduate Studies, Toronto Metropolitan University (formerly Ryerson University), Toronto, ON, Canada
| | - Daniel Rappaport
- Molecular Science Program, Yeates School of Graduate Studies, Toronto Metropolitan University (formerly Ryerson University), Toronto, ON, Canada
| | - Sirasie P Magalage
- Molecular Science Program, Yeates School of Graduate Studies, Toronto Metropolitan University (formerly Ryerson University), Toronto, ON, Canada
| | - Sarah A Sabatinos
- Molecular Science Program, Yeates School of Graduate Studies, Toronto Metropolitan University (formerly Ryerson University), Toronto, ON, Canada.
- Department of Chemistry and Biology, Toronto Metropolitan University (formerly Ryerson University), Toronto, ON, Canada.
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8
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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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9
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Vicente-Soler J, Soto T, Franco A, Cansado J, Madrid M. The Multiple Functions of Rho GTPases in Fission Yeasts. Cells 2021; 10:1422. [PMID: 34200466 PMCID: PMC8228308 DOI: 10.3390/cells10061422] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 06/03/2021] [Accepted: 06/04/2021] [Indexed: 01/20/2023] Open
Abstract
The Rho family of GTPases represents highly conserved molecular switches involved in a plethora of physiological processes. Fission yeast Schizosaccharomyces pombe has become a fundamental model organism to study the functions of Rho GTPases over the past few decades. In recent years, another fission yeast species, Schizosaccharomyces japonicus, has come into focus offering insight into evolutionary changes within the genus. Both fission yeasts contain only six Rho-type GTPases that are spatiotemporally controlled by multiple guanine-nucleotide exchange factors (GEFs) and GTPase-activating proteins (GAPs), and whose intricate regulation in response to external cues is starting to be uncovered. In the present review, we will outline and discuss the current knowledge and recent advances on how the fission yeasts Rho family GTPases regulate essential physiological processes such as morphogenesis and polarity, cellular integrity, cytokinesis and cellular differentiation.
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Affiliation(s)
| | | | | | - José Cansado
- Yeast Physiology Group, Departamento de Genética y Microbiología, Facultad de Biología, Universidad de Murcia, 30100 Murcia, Spain; (J.V.-S.); (T.S.); (A.F.)
| | - Marisa Madrid
- Yeast Physiology Group, Departamento de Genética y Microbiología, Facultad de Biología, Universidad de Murcia, 30100 Murcia, Spain; (J.V.-S.); (T.S.); (A.F.)
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10
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Edreira T, Celador R, Manjón E, Sánchez Y. A novel checkpoint pathway controls actomyosin ring constriction trigger in fission yeast. eLife 2020; 9:59333. [PMID: 33103994 PMCID: PMC7661037 DOI: 10.7554/elife.59333] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 10/24/2020] [Indexed: 12/12/2022] Open
Abstract
In fission yeast, the septation initiation network (SIN) ensures temporal coordination between actomyosin ring (CAR) constriction with membrane ingression and septum synthesis. However, questions remain about CAR regulation under stress conditions. We show that Rgf1p (Rho1p GEF), participates in a delay of cytokinesis under cell wall stress (blankophor, BP). BP did not interfere with CAR assembly or the rate of CAR constriction, but did delay the onset of constriction in the wild type cells but not in the rgf1Δ cells. This delay was also abolished in the absence of Pmk1p, the MAPK of the cell integrity pathway (CIP), leading to premature abscission and a multi-septated phenotype. Moreover, cytokinesis delay correlates with maintained SIN signaling and depends on the SIN to be achieved. Thus, we propose that the CIP participates in a checkpoint, capable of triggering a CAR constriction delay through the SIN pathway to ensure that cytokinesis terminates successfully.
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Affiliation(s)
- Tomás Edreira
- Instituto de Biología Funcional y Genómica, CSIC/Universidad de Salamanca and Departamento de Microbiología y Genética, Universidad de Salamanca, Salamanca, Spain
| | - Rubén Celador
- Instituto de Biología Funcional y Genómica, CSIC/Universidad de Salamanca and Departamento de Microbiología y Genética, Universidad de Salamanca, Salamanca, Spain
| | - Elvira Manjón
- Instituto de Biología Funcional y Genómica, CSIC/Universidad de Salamanca and Departamento de Microbiología y Genética, Universidad de Salamanca, Salamanca, Spain
| | - Yolanda Sánchez
- Instituto de Biología Funcional y Genómica, CSIC/Universidad de Salamanca and Departamento de Microbiología y Genética, Universidad de Salamanca, Salamanca, Spain
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11
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Bohnert KA, Rossi AM, Jin QW, Chen JS, Gould KL. Phosphoregulation of the cytokinetic protein Fic1 contributes to fission yeast growth polarity establishment. J Cell Sci 2020; 133:jcs244392. [PMID: 32878942 PMCID: PMC7520453 DOI: 10.1242/jcs.244392] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Accepted: 08/12/2020] [Indexed: 11/20/2022] Open
Abstract
Cellular polarization underlies many facets of cell behavior, including cell growth. The rod-shaped fission yeast Schizosaccharomyces pombe is a well-established, genetically tractable system for studying growth polarity regulation. S. pombe cells elongate at their two cell tips in a cell cycle-controlled manner, transitioning from monopolar to bipolar growth in interphase when new ends established by the most recent cell division begin to extend. We previously identified cytokinesis as a critical regulator of new end growth and demonstrated that Fic1, a cytokinetic factor, is required for normal polarized growth at new ends. Here, we report that Fic1 is phosphorylated on two C-terminal residues, which are each targeted by multiple protein kinases. Endogenously expressed Fic1 phosphomutants cannot support proper bipolar growth, and the resultant defects facilitate the switch into an invasive pseudohyphal state. Thus, phosphoregulation of Fic1 links the completion of cytokinesis to the re-establishment of polarized growth in the next cell cycle. These findings broaden the scope of signaling events that contribute to regulating S. pombe growth polarity, underscoring that cytokinetic factors constitute relevant targets of kinases affecting new end growth.This article has an associated First Person interview with Anthony M. Rossi, joint first author of the paper.
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Affiliation(s)
- K Adam Bohnert
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240, USA
| | - Anthony M Rossi
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240, USA
| | - Quan-Wen Jin
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240, USA
| | - Jun-Song Chen
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240, USA
| | - Kathleen L Gould
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240, USA
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12
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Bhattacharjee R, Mangione MC, Wos M, Chen JS, Snider CE, Roberts-Galbraith RH, McDonald NA, Presti LL, Martin SG, Gould KL. DYRK kinase Pom1 drives F-BAR protein Cdc15 from the membrane to promote medial division. Mol Biol Cell 2020; 31:917-929. [PMID: 32101481 PMCID: PMC7185970 DOI: 10.1091/mbc.e20-01-0026] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
In many organisms, positive and negative signals cooperate to position the division site for cytokinesis. In the rod-shaped fission yeast Schizosaccharomyces pombe, symmetric division is achieved through anillin/Mid1-dependent positive cues released from the central nucleus and negative signals from the DYRK-family polarity kinase Pom1 at cell tips. Here we establish that Pom1's kinase activity prevents septation at cell tips even if Mid1 is absent or mislocalized. We also find that Pom1 phosphorylation of F-BAR protein Cdc15, a major scaffold of the division apparatus, disrupts Cdc15's ability to bind membranes and paxillin, Pxl1, thereby inhibiting Cdc15's function in cytokinesis. A Cdc15 mutant carrying phosphomimetic versions of Pom1 sites or deletion of Cdc15 binding partners suppresses division at cell tips in cells lacking both Mid1 and Pom1 signals. Thus, inhibition of Cdc15-scaffolded septum formation at cell poles is a key Pom1 mechanism that ensures medial division.
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Affiliation(s)
- Rahul Bhattacharjee
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37205
| | - MariaSanta C Mangione
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37205
| | - Marcin Wos
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37205
| | - Jun-Song Chen
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37205
| | - Chloe E Snider
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37205
| | - Rachel H Roberts-Galbraith
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37205
| | - Nathan A McDonald
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37205
| | - Libera Lo Presti
- Department of Fundamental Microbiology, University of Lausanne, 1015 Lausanne, Switzerland
| | - Sophie G Martin
- Department of Fundamental Microbiology, University of Lausanne, 1015 Lausanne, Switzerland
| | - Kathleen L Gould
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37205
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13
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Willet AH, Bohnert KA, Gould KL. Cdk1-dependent phosphoinhibition of a formin-F-BAR interaction opposes cytokinetic contractile ring formation. Mol Biol Cell 2018; 29:713-721. [PMID: 29343550 PMCID: PMC6003227 DOI: 10.1091/mbc.e17-11-0646] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 01/04/2018] [Accepted: 01/09/2018] [Indexed: 11/11/2022] Open
Abstract
In Schizosaccharomyces pombe, cytokinesis requires the assembly and constriction of an actomyosin-based contractile ring (CR). A single essential formin, Cdc12, localizes to the cell middle upon mitotic onset and nucleates the F-actin of the CR. Cdc12 medial recruitment is mediated in part by its direct binding to the F-BAR scaffold Cdc15. Given that Cdc12 is hyperphosphorylated in M phase, we explored whether Cdc12 phosphoregulation impacts its association with Cdc15 during mitosis. We found that Cdk1, a major mitotic kinase, phosphorylates Cdc12 on six N-terminal residues near the Cdc15-binding site, and phosphorylation on these sites inhibits its interaction with the Cdc15 F-BAR domain. Consistent with this finding, a cdc12 mutant with all six Cdk1 sites changed to phosphomimetic residues (cdc12-6D) displays phenotypes similar to cdc12-P31A, in which the Cdc15-binding motif is disrupted; both show reduced Cdc12 at the CR and delayed CR formation. Together, these results indicate that Cdk1 phosphorylation of formin Cdc12 antagonizes its interaction with Cdc15 and thereby opposes Cdc12's CR localization. These results are consistent with a general role for Cdk1 in inhibiting cytokinesis until chromosome segregation is complete.
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Affiliation(s)
- Alaina H Willet
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - K Adam Bohnert
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Kathleen L Gould
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232
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14
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Abstract
A conserved molecular machinery centered on the Cdc42 GTPase regulates cell polarity in diverse organisms. Here we review findings from budding and fission yeasts that reveal both a conserved core polarity circuit and several adaptations that each organism exploits to fulfill the needs of its lifestyle. The core circuit involves positive feedback by local activation of Cdc42 to generate a cluster of concentrated GTP-Cdc42 at the membrane. Species-specific pathways regulate the timing of polarization during the cell cycle, as well as the location and number of polarity sites.
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Affiliation(s)
- Jian-Geng Chiou
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710;
| | - Mohan K Balasubramanian
- Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Daniel J Lew
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710;
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15
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McDonald NA, Lind AL, Smith SE, Li R, Gould KL. Nanoscale architecture of the Schizosaccharomyces pombe contractile ring. eLife 2017; 6:28865. [PMID: 28914606 PMCID: PMC5779233 DOI: 10.7554/elife.28865] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Accepted: 09/14/2017] [Indexed: 12/13/2022] Open
Abstract
The contractile ring is a complex molecular apparatus which physically divides many eukaryotic cells. Despite knowledge of its protein composition, the molecular architecture of the ring is not known. Here we have applied super-resolution microscopy and FRET to determine the nanoscale spatial organization of Schizosaccharomyces pombe contractile ring components relative to the plasma membrane. Similar to other membrane-tethered actin structures, we find proteins localize in specific layers relative to the membrane. The most membrane-proximal layer (0–80 nm) is composed of membrane-binding scaffolds, formin, and the tail of the essential myosin-II. An intermediate layer (80–160 nm) consists of a network of cytokinesis accessory proteins as well as multiple signaling components which influence cell division. Farthest from the membrane (160–350 nm) we find F-actin, the motor domains of myosins, and a major F-actin crosslinker. Circumferentially within the ring, multiple proteins proximal to the membrane form clusters of different sizes, while components farther from the membrane are uniformly distributed. This comprehensive organizational map provides a framework for understanding contractile ring function.
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Affiliation(s)
- Nathan A McDonald
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, United States
| | - Abigail L Lind
- Department of Biomedical Informatics, Vanderbilt University Medical Center, Nashville, United States
| | - Sarah E Smith
- Stowers Institute for Medical Research, Kansas City, United States
| | - Rong Li
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Kathleen L Gould
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, United States
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16
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Liu Y, Lee IJ, Sun M, Lower CA, Runge KW, Ma J, Wu JQ. Roles of the novel coiled-coil protein Rng10 in septum formation during fission yeast cytokinesis. Mol Biol Cell 2016; 27:2528-41. [PMID: 27385337 PMCID: PMC4985255 DOI: 10.1091/mbc.e16-03-0156] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 06/21/2016] [Indexed: 12/31/2022] Open
Abstract
The regulation of Rho-GAP localization is not well understood. A novel coiled-coil protein Rng10 is characterized that localizes the Rho-GAP Rga7 in fission yeast. Rng10 and Rga7 physically interact and work together to regulate the accumulation and dynamics of glucan synthases for successful septum formation during cytokinesis. Rho GAPs are important regulators of Rho GTPases, which are involved in various steps of cytokinesis and other processes. However, regulation of Rho-GAP cellular localization and function is not fully understood. Here we report the characterization of a novel coiled-coil protein Rng10 and its relationship with the Rho-GAP Rga7 in fission yeast. Both rng10Δ and rga7Δ result in defective septum and cell lysis during cytokinesis. Rng10 and Rga7 colocalize on the plasma membrane at the cell tips during interphase and at the division site during cell division. Rng10 physically interacts with Rga7 in affinity purification and coimmunoprecipitation. Of interest, Rga7 localization is nearly abolished without Rng10. Moreover, Rng10 and Rga7 work together to regulate the accumulation and dynamics of glucan synthases for successful septum formation in cytokinesis. Our results show that cellular localization and function of the Rho-GAP Rga7 are regulated by a novel protein, Rng10, during cytokinesis in fission yeast.
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Affiliation(s)
- Yajun Liu
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210
| | - I-Ju Lee
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210
| | - Mingzhai Sun
- Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210
| | - Casey A Lower
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210
| | - Kurt W Runge
- Department of Molecular Genetics, Cleveland Clinic Lerner College of Medicine, Cleveland, OH 44195
| | - Jianjie Ma
- Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210
| | - Jian-Qiu Wu
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210 Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH 43210
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17
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Oligomerization but Not Membrane Bending Underlies the Function of Certain F-BAR Proteins in Cell Motility and Cytokinesis. Dev Cell 2016; 35:725-36. [PMID: 26702831 DOI: 10.1016/j.devcel.2015.11.023] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Revised: 10/12/2015] [Accepted: 11/21/2015] [Indexed: 12/22/2022]
Abstract
F-BAR proteins function in diverse cellular processes by linking membranes to the actin cytoskeleton. Through oligomerization, multiple F-BAR domains can bend membranes into tubules, though the physiological importance of F-BAR-to-F-BAR assemblies is not yet known. Here, we investigate the F-BAR domain of the essential cytokinetic scaffold, Schizosaccharomyces pombe Cdc15, during cytokinesis. Challenging a widely held view that membrane deformation is a fundamental property of F-BARs, we report that the Cdc15 F-BAR binds, but does not deform, membranes in vivo or in vitro, and six human F-BAR domains-including those from Fer and RhoGAP4-share this property. Nevertheless, tip-to-tip interactions between F-BAR dimers are critical for Cdc15 oligomerization and high-avidity membrane binding, stabilization of contractile ring components at the medial cortex, and the fidelity of cytokinesis. F-BAR oligomerization is also critical for Fer and RhoGAP4 physiological function, demonstrating its broad importance to F-BAR proteins that function without membrane bending.
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18
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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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19
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McDonald NA, Takizawa Y, Feoktistova A, Xu P, Ohi MD, Vander Kooi CW, Gould KL. The Tubulation Activity of a Fission Yeast F-BAR Protein Is Dispensable for Its Function in Cytokinesis. Cell Rep 2016; 14:534-546. [PMID: 26776521 PMCID: PMC4731314 DOI: 10.1016/j.celrep.2015.12.062] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Revised: 11/23/2015] [Accepted: 12/10/2015] [Indexed: 11/28/2022] Open
Abstract
F-BAR proteins link cellular membranes to the actin cytoskeleton in many biological processes. Here we investigated the function of the Schizosaccharomyces pombe Imp2 F-BAR domain in cytokinesis and find that it is critical for Imp2's role in contractile ring constriction and disassembly. To understand mechanistically how the F-BAR domain functions, we determined its structure, elucidated how it interacts with membranes, and identified an interaction between dimers that allows helical oligomerization and membrane tubulation. Using mutations that block either membrane binding or tubulation, we find that membrane binding is required for Imp2's cytokinetic function but that oligomerization and tubulation, activities often deemed central to F-BAR protein function, are dispensable. Accordingly, F-BARs that do not have the capacity to tubulate membranes functionally substitute for the Imp2 F-BAR, establishing that its major role is as a cell-cycle-regulated bridge between the membrane and Imp2 protein partners, rather than as a driver of membrane curvature.
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Affiliation(s)
- Nathan A McDonald
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37240, USA
| | - Yoshimasa Takizawa
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37240, USA; Center for Structural Biology, Vanderbilt University, Nashville, TN 37240, USA
| | - Anna Feoktistova
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37240, USA
| | - Ping Xu
- Department of Molecular and Cellular Biochemistry and Center for Structural Biology, University of Kentucky, Lexington, KY 40536, USA
| | - Melanie D Ohi
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37240, USA; Center for Structural Biology, Vanderbilt University, Nashville, TN 37240, USA
| | - Craig W Vander Kooi
- Department of Molecular and Cellular Biochemistry and Center for Structural Biology, University of Kentucky, Lexington, KY 40536, USA
| | - Kathleen L Gould
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37240, USA.
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20
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Rincon SA, Paoletti A. Molecular control of fission yeast cytokinesis. Semin Cell Dev Biol 2016; 53:28-38. [PMID: 26806637 DOI: 10.1016/j.semcdb.2016.01.007] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 01/06/2016] [Indexed: 12/29/2022]
Abstract
Cytokinesis gives rise to two independent daughter cells at the end of the cell division cycle. The fission yeast Schizosaccharomyces pombe has emerged as one of the most powerful systems to understand how cytokinesis is controlled molecularly. Like in most eukaryotes, fission yeast cytokinesis depends on an acto-myosin based contractile ring that assembles at the division site under the control of spatial cues that integrate information on cell geometry and the position of the mitotic apparatus. Cytokinetic events are also tightly coordinated with nuclear division by the cell cycle machinery. These spatial and temporal regulations ensure an equal cleavage of the cytoplasm and an accurate segregation of the genetic material in daughter cells. Although this model system has specificities, the basic mechanisms of contractile ring assembly and function deciphered in fission yeast are highly valuable to understand how cytokinesis is controlled in other organisms that rely on a contractile ring for cell division.
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Affiliation(s)
- Sergio A Rincon
- Institut Curie, Centre de Recherche, PSL Research University, F-75248 Paris, France; CNRS UMR144, F-75248 Paris, France
| | - Anne Paoletti
- Institut Curie, Centre de Recherche, PSL Research University, F-75248 Paris, France; CNRS UMR144, F-75248 Paris, France.
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21
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Ullal P, McDonald NA, Chen JS, Lo Presti L, Roberts-Galbraith RH, Gould KL, Martin SG. The DYRK-family kinase Pom1 phosphorylates the F-BAR protein Cdc15 to prevent division at cell poles. J Cell Biol 2015; 211:653-68. [PMID: 26553932 PMCID: PMC4639868 DOI: 10.1083/jcb.201504073] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Accepted: 10/01/2015] [Indexed: 12/14/2022] Open
Abstract
Division site positioning is critical for both symmetric and asymmetric cell divisions. In many organisms, positive and negative signals cooperate to position the contractile actin ring for cytokinesis. In rod-shaped fission yeast Schizosaccharomyces pombe cells, division at midcell is achieved through positive Mid1/anillin-dependent signaling emanating from the central nucleus and negative signals from the dual-specificity tyrosine phosphorylation-regulated kinase family kinase Pom1 at the cell poles. In this study, we show that Pom1 directly phosphorylates the F-BAR protein Cdc15, a central component of the cytokinetic ring. Pom1-dependent phosphorylation blocks Cdc15 binding to paxillin Pxl1 and C2 domain protein Fic1 and enhances Cdc15 dynamics. This promotes ring sliding from cell poles, which prevents septum assembly at the ends of cells with a displaced nucleus or lacking Mid1. Pom1 also slows down ring constriction. These results indicate that a strong negative signal from the Pom1 kinase at cell poles converts Cdc15 to its closed state, destabilizes the actomyosin ring, and thus promotes medial septation.
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Affiliation(s)
- Pranav Ullal
- Department of Fundamental Microbiology, University of Lausanne, CH-1015 Lausanne, Switzerland
| | - Nathan A McDonald
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Jun-Song Chen
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Libera Lo Presti
- Department of Fundamental Microbiology, University of Lausanne, CH-1015 Lausanne, Switzerland
| | - Rachel H Roberts-Galbraith
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Kathleen L Gould
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Sophie G Martin
- Department of Fundamental Microbiology, University of Lausanne, CH-1015 Lausanne, Switzerland
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22
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Willet AH, McDonald NA, Gould KL. Regulation of contractile ring formation and septation in Schizosaccharomyces pombe. Curr Opin Microbiol 2015; 28:46-52. [PMID: 26340438 DOI: 10.1016/j.mib.2015.08.001] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Revised: 08/01/2015] [Accepted: 08/07/2015] [Indexed: 01/14/2023]
Abstract
The fission yeast Schizosaccharomyces pombe has become a powerful model organism for cytokinesis studies, propelled by pioneering genetic screens in the 1980s and 1990s. S. pombe cells are rod-shaped and divide similarly to mammalian cells, utilizing a medially-placed actin-and myosin-based contractile ring. A cell wall division septum is deposited behind the constricting ring, forming the new ends of each daughter cell. Here we discuss recent advances in our understanding of the regulation of contractile ring formation through formin proteins and the role of the division septum in S. pombe cell division.
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Affiliation(s)
- Alaina H Willet
- Department of Cell and Developmental Biology, PMB 407935, 465 21st Ave S., Vanderbilt University School of Medicine, Nashville, TN, United States
| | - Nathan A McDonald
- Department of Cell and Developmental Biology, PMB 407935, 465 21st Ave S., Vanderbilt University School of Medicine, Nashville, TN, United States
| | - Kathleen L Gould
- Department of Cell and Developmental Biology, PMB 407935, 465 21st Ave S., Vanderbilt University School of Medicine, Nashville, TN, United States.
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23
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Ren L, Willet AH, Roberts-Galbraith RH, McDonald NA, Feoktistova A, Chen JS, Huang H, Guillen R, Boone C, Sidhu SS, Beckley JR, Gould KL. The Cdc15 and Imp2 SH3 domains cooperatively scaffold a network of proteins that redundantly ensure efficient cell division in fission yeast. Mol Biol Cell 2014; 26:256-69. [PMID: 25428987 PMCID: PMC4294673 DOI: 10.1091/mbc.e14-10-1451] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The fission yeast F-BAR proteins Cdc15 and Imp2 and their combined SH3-domain partners appear to act as “molecular glue” to stabilize the interaction between the plasma membrane and a complex network of proteins at the division site that mediates cell division. Schizosaccharomyces pombe cdc15 homology (PCH) family members participate in numerous biological processes, including cytokinesis, typically by bridging the plasma membrane via their F-BAR domains to the actin cytoskeleton. Two SH3 domain–containing PCH family members, Cdc15 and Imp2, play critical roles in S. pombe cytokinesis. Although both proteins localize to the contractile ring, with Cdc15 preceding Imp2, only cdc15 is an essential gene. Despite these distinct roles, the SH3 domains of Cdc15 and Imp2 cooperate in the essential process of recruiting other proteins to stabilize the contractile ring. To better understand the connectivity of this SH3 domain–based protein network at the CR and its function, we used a biochemical approach coupled to proteomics to identify additional proteins (Rgf3, Art1, Spa2, and Pos1) that are integrated into this network. Cell biological and genetic analyses of these SH3 partners implicate them in a range of activities that ensure the fidelity of cell division, including promoting cell wall metabolism and influencing cell morphogenesis.
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Affiliation(s)
- Liping Ren
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Alaina H Willet
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Rachel H Roberts-Galbraith
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Nathan A McDonald
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Anna Feoktistova
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Jun-Song Chen
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Haiming Huang
- Terrence Donnelly Center for Cellular and Biomolecular Research, Banting and Best Department of Medical Research, University of Toronto, Toronto, ON M5G 1L6, Canada
| | - Rodrigo Guillen
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Charles Boone
- Terrence Donnelly Center for Cellular and Biomolecular Research, Banting and Best Department of Medical Research, University of Toronto, Toronto, ON M5G 1L6, Canada
| | - Sachdev S Sidhu
- Terrence Donnelly Center for Cellular and Biomolecular Research, Banting and Best Department of Medical Research, University of Toronto, Toronto, ON M5G 1L6, Canada
| | - Janel R Beckley
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Kathleen L Gould
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232
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24
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Wang N, Wang M, Zhu YH, Grosel TW, Sun D, Kudryashov DS, Wu JQ. The Rho-GEF Gef3 interacts with the septin complex and activates the GTPase Rho4 during fission yeast cytokinesis. Mol Biol Cell 2014; 26:238-55. [PMID: 25411334 PMCID: PMC4294672 DOI: 10.1091/mbc.e14-07-1196] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Rho GTPases, activated by Rho guanine nucleotide exchange factors (GEFs), are conserved molecular switches for signal transductions that regulate diverse cellular processes, including cell polarization and cytokinesis. The fission yeast Schizosaccharomyces pombe has six Rho GTPases (Cdc42 and Rho1-Rho5) and seven Rho GEFs (Scd1, Rgf1-Rgf3, and Gef1-Gef3). The GEFs for Rho2-Rho5 have not been unequivocally assigned. In particular, Gef3, the smallest Rho GEF, was barely studied. Here we show that Gef3 colocalizes with septins at the cell equator. Gef3 physically interacts with septins and anillin Mid2 and depends on them to localize. Gef3 coprecipitates with GDP-bound Rho4 in vitro and accelerates nucleotide exchange of Rho4, suggesting that Gef3 is a GEF for Rho4. Consistently, Gef3 and Rho4 are in the same genetic pathways to regulate septum formation and/or cell separation. In gef3∆ cells, the localizations of two potential Rho4 effectors--glucanases Eng1 and Agn1--are abnormal, and active Rho4 level is reduced, indicating that Gef3 is involved in Rho4 activation in vivo. Moreover, overexpression of active Rho4 or Eng1 rescues the septation defects of mutants containing gef3∆. Together our data support that Gef3 interacts with the septin complex and activates Rho4 GTPase as a Rho GEF for septation in fission yeast.
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Affiliation(s)
| | - Mo Wang
- Department of Molecular Genetics
| | | | | | | | | | - Jian-Qiu Wu
- Department of Molecular Genetics Department of Molecular and Cellular Biochemistry, The Ohio State University, Columbus, OH 43210
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25
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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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26
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Martin SG, Arkowitz RA. Cell polarization in budding and fission yeasts. FEMS Microbiol Rev 2014; 38:228-53. [DOI: 10.1111/1574-6976.12055] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Revised: 11/13/2013] [Accepted: 12/03/2013] [Indexed: 11/30/2022] Open
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