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Rich-Robinson J, Russell A, Mancini E, Das M. Cdc42 reactivation at growth sites is regulated by local cell-cycle-dependent loss of its GTPase-activating protein Rga4 in fission yeast. J Cell Sci 2021; 134:272049. [PMID: 34523683 DOI: 10.1242/jcs.259291] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 08/18/2021] [Indexed: 12/18/2022] Open
Abstract
In fission yeast, polarized cell growth stops during division and resumes after cytokinesis completes and cells separate. It is unclear how growth reactivation is timed to occur immediately after cell separation. We uncoupled these sequential events by delaying cytokinesis with a temporary Latrunculin A treatment. Mitotic cells recovering from treatment initiate end growth during septation, displaying a polar elongation simultaneous with septation (PrESS) phenotype. PrESS cell ends reactivate Cdc42, a major regulator of polarized growth, during septation, but at a fixed time after anaphase B. A candidate screen implicates Rga4, a negative regulator of Cdc42, in this process. We show that Rga4 appears punctate at the cell sides during G2, but is diffuse during mitosis, extending to the ends. Although the Morphogenesis Orb6 (MOR) pathway is known to promote cell separation and growth by activating protein synthesis, we find that, for polarized growth, removal of Rga4 from the ends is also necessary. Therefore, we propose that growth resumes after division once the MOR pathway is activated and the ends lose Rga4 in a cell-cycle-dependent manner.
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Affiliation(s)
- Julie Rich-Robinson
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
| | - Afton Russell
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
| | - Eleanor Mancini
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
| | - Maitreyi Das
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
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2
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García P, Coll PM, Del Rey F, Geli MI, Pérez P, Vázquez de Aldana CR, Encinar Del Dedo J. Eng2, a new player involved in feedback loop regulation of Cdc42 activity in fission yeast. Sci Rep 2021; 11:17872. [PMID: 34504165 PMCID: PMC8429772 DOI: 10.1038/s41598-021-97311-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 08/05/2021] [Indexed: 11/09/2022] Open
Abstract
Cell polarity and morphogenesis are regulated by the small GTPase Cdc42. Even though major advances have been done in the field during the last years, the molecular details leading to its activation in particular cellular contexts are not completely understood. In fission yeast, the β(1,3)-glucanase Eng2 is a "moonlighting protein" with a dual function, acting as a hydrolase during spore dehiscence, and as component of the endocytic machinery in vegetative cells. Here, we report that Eng2 plays a role in Cdc42 activation during polarized growth through its interaction with the scaffold protein Scd2, which brings Cdc42 together with its guanine nucleotide exchange factor (GEF) Scd1. eng2Δ mutant cells have defects in activation of the bipolar growth (NETO), remaining monopolar during all the cell cycle. In the absence of Eng2 the accumulation of Scd1 and Scd2 at the poles is reduced, the levels of Cdc42 activation decrease, and the Cdc42 oscillatory behavior, associated with bipolar growth in wild type cells, is altered. Furthermore, overexpression of Eng2 partially rescues the growth and polarity defects of a cdc42-L160S mutant. Altogether, our work unveils a new factor regulating the activity of Cdc42, which could potentially link the polarity and endocytic machineries.
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Affiliation(s)
- Patricia García
- Instituto de Biología Funcional y Genómica, CSIC/Universidad de Salamanca, c/ Zacarías González 2, 37007, Salamanca, Spain
| | - Pedro M Coll
- Instituto de Biología Funcional y Genómica, CSIC/Universidad de Salamanca, c/ Zacarías González 2, 37007, Salamanca, Spain
| | - Francisco Del Rey
- Instituto de Biología Funcional y Genómica, CSIC/Universidad de Salamanca, c/ Zacarías González 2, 37007, Salamanca, Spain
| | - M Isabel Geli
- Institute for Molecular Biology of Barcelona (CSIC), Baldiri Reixac 15, 08028, Barcelona, Spain
| | - Pilar Pérez
- Instituto de Biología Funcional y Genómica, CSIC/Universidad de Salamanca, c/ Zacarías González 2, 37007, Salamanca, Spain
| | - Carlos R Vázquez de Aldana
- Instituto de Biología Funcional y Genómica, CSIC/Universidad de Salamanca, c/ Zacarías González 2, 37007, Salamanca, Spain.
| | - Javier Encinar Del Dedo
- Instituto de Biología Funcional y Genómica, CSIC/Universidad de Salamanca, c/ Zacarías González 2, 37007, Salamanca, Spain.
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3
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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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4
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Onwubiko UN, Rich-Robinson J, Mustaf RA, Das ME. Cdc42 promotes Bgs1 recruitment for septum synthesis and glucanase localization for cell separation during cytokinesis in fission yeast. Small GTPases 2020; 12:257-264. [PMID: 32182184 DOI: 10.1080/21541248.2020.1743926] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Cytokinesis in fission yeast involves actomyosin ring constriction concurrent to septum synthesis followed by septum digestion resulting in cell separation. A recent report indicates that endocytosis is required for septum synthesis and cell separation. The conserved GTPase Cdc42 is required for membrane trafficking and promotes endocytosis. Cdc42 is activated by Guanine nucleotide exchange factors (GEFs). Cdc42 GEFs have been shown to promote timely initiation of septum synthesis and proper septum morphology. Here we show that Cdc42 promotes the recruitment of the major primary septum synthesizing enzyme Bgs1 and consequent ring constriction. Cdc42 is also required for proper localization of the septum digesting glucanases at the division site. Thus, Cdc42 is required to promote multiple steps during cytokinesis.
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Affiliation(s)
- Udo N Onwubiko
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, USA
| | - Julie Rich-Robinson
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, USA
| | - Rose Albu Mustaf
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, USA
| | - Maitreyi E Das
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, USA
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5
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Hercyk BS, Rich-Robinson J, Mitoubsi AS, Harrell MA, Das ME. A novel interplay between GEFs orchestrates Cdc42 activity during cell polarity and cytokinesis in fission yeast. J Cell Sci 2019; 132:jcs.236018. [PMID: 31719163 DOI: 10.1242/jcs.229252/video-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 11/04/2019] [Indexed: 05/23/2023] Open
Abstract
Cdc42, a conserved regulator of cell polarity, is activated by two GEFs, Gef1 and Scd1, in fission yeast. Why the cell needs two GEFs is unclear, given that they are partially redundant and activate the same GTPase. Using the GEF localization pattern during cytokinesis as a paradigm, we report a novel interplay between Gef1 and Scd1 that spatially modulates Cdc42. We find that Gef1 promotes Scd1 localization to the division site during cytokinesis through recruitment of the scaffold protein Scd2, via a Cdc42 feedforward pathway. Similarly, during interphase Gef1 promotes Scd1 recruitment at the new end to enable the transition from monopolar to bipolar growth. Reciprocally, Scd1 restricts Gef1 localization to prevent ectopic Cdc42 activation during cytokinesis to promote cell separation, and to maintain cell shape during interphase. Our findings reveal an elegant regulatory pattern in which Gef1 primes Cdc42 activation at new sites to initiate Scd1-dependent polarized growth, while Scd1 restricts Gef1 to sites of polarization. We propose that crosstalk between GEFs is a conserved mechanism that orchestrates Cdc42 activation during complex cellular processes.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Brian S Hercyk
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 7996-1939, USA
| | - Julie Rich-Robinson
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 7996-1939, USA
| | - Ahmad S Mitoubsi
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 7996-1939, USA
| | - Marcus A Harrell
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 7996-1939, USA
| | - Maitreyi E Das
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 7996-1939, USA
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6
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Hercyk BS, Rich-Robinson J, Mitoubsi AS, Harrell MA, Das ME. A novel interplay between GEFs orchestrates Cdc42 activity during cell polarity and cytokinesis in fission yeast. J Cell Sci 2019; 132:jcs.236018. [PMID: 31719163 DOI: 10.1242/jcs.236018] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 11/04/2019] [Indexed: 12/12/2022] Open
Abstract
Cdc42, a conserved regulator of cell polarity, is activated by two GEFs, Gef1 and Scd1, in fission yeast. Why the cell needs two GEFs is unclear, given that they are partially redundant and activate the same GTPase. Using the GEF localization pattern during cytokinesis as a paradigm, we report a novel interplay between Gef1 and Scd1 that spatially modulates Cdc42. We find that Gef1 promotes Scd1 localization to the division site during cytokinesis through recruitment of the scaffold protein Scd2, via a Cdc42 feedforward pathway. Similarly, during interphase Gef1 promotes Scd1 recruitment at the new end to enable the transition from monopolar to bipolar growth. Reciprocally, Scd1 restricts Gef1 localization to prevent ectopic Cdc42 activation during cytokinesis to promote cell separation, and to maintain cell shape during interphase. Our findings reveal an elegant regulatory pattern in which Gef1 primes Cdc42 activation at new sites to initiate Scd1-dependent polarized growth, while Scd1 restricts Gef1 to sites of polarization. We propose that crosstalk between GEFs is a conserved mechanism that orchestrates Cdc42 activation during complex cellular processes.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Brian S Hercyk
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 7996-1939, USA
| | - Julie Rich-Robinson
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 7996-1939, USA
| | - Ahmad S Mitoubsi
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 7996-1939, USA
| | - Marcus A Harrell
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 7996-1939, USA
| | - Maitreyi E Das
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 7996-1939, USA
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7
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Hercyk BS, Das ME. F-BAR Cdc15 Promotes Cdc42 Activation During Cytokinesis and Cell Polarization in Schizosaccharomyces pombe. Genetics 2019; 213:1341-1356. [PMID: 31591131 PMCID: PMC6893373 DOI: 10.1534/genetics.119.302649] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 09/23/2019] [Indexed: 01/21/2023] Open
Abstract
Cdc42, a Rho-family GTPase, is a master regulator of cell polarity. Recently, it has been shown that Cdc42 also facilitates proper cytokinesis in the fission yeast Schizosaccharomyces pombe Cdc42 is activated by two partially redundant GEFs, Gef1 and Scd1. Although both GEFs activate Cdc42, their deletion mutants display distinct phenotypes, indicating that they are differentially regulated by an unknown mechanism. During cytokinesis, Gef1 localizes to the division site and activates Cdc42 to initiate ring constriction and septum ingression. Here, we report that the F-BAR protein Cdc15 promotes Gef1 localization to its functional sites. We show that cdc15 promotes Gef1 association with cortical puncta at the incipient division site to activate Cdc42 during ring assembly. Moreover, cdc15 phospho-mutants phenocopy the polarity phenotypes of gef1 mutants. In a hypermorphic cdc15 mutant, Gef1 localizes precociously to the division site and is readily detected at the cortical patches and the cell cortex. Correspondingly, the hypermorphic cdc15 mutant shows increased bipolarity during interphase and precocious Cdc42 activation at the division site during cytokinesis. Finally, loss of gef1 in hypermorphic cdc15 mutants abrogates the increased bipolarity and precocious Cdc42 activation phenotype. We did not see any change in the localization of the other GEF Scd1 in a Cdc15-dependent manner. Our data indicate that Cdc15 facilitates Cdc42 activation at the division site during cytokinesis at the cell cortex to promote bipolarity and this is mediated by promoting Gef1 localization to these sites.
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Affiliation(s)
- Brian S Hercyk
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996
| | - Maitreyi E Das
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996
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8
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Hercyk BS, Onwubiko UN, Das ME. Coordinating septum formation and the actomyosin ring during cytokinesis in Schizosaccharomyces pombe. Mol Microbiol 2019; 112:1645-1657. [PMID: 31533197 PMCID: PMC6904431 DOI: 10.1111/mmi.14387] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/12/2019] [Indexed: 01/08/2023]
Abstract
During cytokinesis, animal and fungal cells form a membrane furrow via actomyosin ring constriction. Our understanding of actomyosin ring-driven cytokinesis stems extensively from the fission yeast model system. However, unlike animal cells, actomyosin ring constriction occurs simultaneously with septum formation in fungi. While the formation of an actomyosin ring is essential for cytokinesis in fission yeast, proper furrow formation also requires septum deposition. The molecular mechanisms of spatiotemporal coordination of septum deposition with actomyosin ring constriction are poorly understood. Although the role of the actomyosin ring as a mechanical structure driving furrow formation is better understood, its role as a spatiotemporal landmark for septum deposition is not widely discussed. Here we review and discuss the recent advances describing how the actomyosin ring spatiotemporally regulates membrane traffic to promote septum-driven cytokinesis in fission yeast. Finally, we explore emerging questions in cytokinesis, and discuss the role of extracellular matrix during cytokinesis in other organisms.
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Affiliation(s)
- Brian S Hercyk
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, 37996, USA
| | - Udo N Onwubiko
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, 37996, USA
| | - Maitreyi E Das
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, 37996, USA
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9
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Hercyk B, Das M. Rho Family GTPases in Fission Yeast Cytokinesis. Commun Integr Biol 2019; 12:171-180. [PMID: 31666919 PMCID: PMC6802929 DOI: 10.1080/19420889.2019.1678453] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 09/20/2019] [Accepted: 09/23/2019] [Indexed: 12/22/2022] Open
Abstract
During cytokinesis, actomyosin ring constriction drives furrow formation. In animal cells, Rho GTPases drive this process through the positioning and assembly of the actomyosin ring, and through extracellular matrix remodeling within the furrow. In the fission yeast S. pombe, actomyosin ring constriction and septum formation are concurrent processes. While S. pombe is the primary source from which the mechanics of ring assembly and constriction stem, much less is known about the regulation of Rho GTPases that control these processes. Of the six Rho GTPases encoded in S. pombe, only Rho1, the RhoA homologue, has been shown to be essential for cytokinesis. While Rho3, Rho4, and Cdc42 have defined roles in cytokinesis, Rho2 and Rho5 play minor to no roles in this process. Here we review the roles of the Rho GTPases during cytokinesis, with a focus on their regulation, and discuss whether crosstalk between GTPases, as has been reported in other organisms, exists during cytokinesis in S. pombe.
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Affiliation(s)
- Brian Hercyk
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, USA
| | - Maitreyi Das
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, USA
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10
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Ramos M, Cortés JCG, Sato M, Rincón SA, Moreno MB, Clemente-Ramos JÁ, Osumi M, Pérez P, Ribas JC. Two S. pombe septation phases differ in ingression rate, septum structure, and response to F-actin loss. J Cell Biol 2019; 218:4171-4194. [PMID: 31597680 PMCID: PMC6891078 DOI: 10.1083/jcb.201808163] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 04/19/2019] [Accepted: 09/10/2019] [Indexed: 12/28/2022] Open
Abstract
Ramos et al. establish that fission yeast septation proceeds in two phases. Initially, the septum is immature and, upon F-actin depolymerization, loses the Bgs1 glucan synthase and fails to ingress. During a second phase, the mature septum can maintain Bgs1 and ingression without F-actin, and ingression becomes Cdc42 and exocyst dependent. In fission yeast, cytokinesis requires a contractile actomyosin ring (CR) coupled to membrane and septum ingression. Septation proceeds in two phases. In anaphase B, the septum ingresses slowly. During telophase, the ingression rate increases, and the CR becomes dispensable. Here, we explore the relationship between the CR and septation by analyzing septum ultrastructure, ingression, and septation proteins in cells lacking F-actin. We show that the two phases of septation correlate with septum maturation and the response of cells to F-actin removal. During the first phase, the septum is immature and, following F-actin removal, rapidly loses the Bgs1 glucan synthase from the membrane edge and fails to ingress. During the second phase, the rapidly ingressing mature septum can maintain a Bgs1 ring and septum ingression without F-actin, but ingression becomes Cdc42 and exocyst dependent. Our results provide new insights into fungal cytokinesis and reveal the dual function of CR as an essential landmark for the concentration of Bgs1 and a contractile structure that maintains septum shape and synthesis.
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Affiliation(s)
- Mariona Ramos
- Instituto de Biología Funcional y Genómica and Departamento de Microbiología y Genética, Consejo Superior de Investigaciones Científicas/Universidad de Salamanca, Salamanca, Spain
| | - Juan Carlos G Cortés
- Instituto de Biología Funcional y Genómica and Departamento de Microbiología y Genética, Consejo Superior de Investigaciones Científicas/Universidad de Salamanca, Salamanca, Spain
| | - Mamiko Sato
- Laboratory of Electron Microscopy/Bio-imaging Center, Japan Women's University, Bunkyo-ku, Tokyo, Japan
| | - Sergio A Rincón
- Instituto de Biología Funcional y Genómica and Departamento de Microbiología y Genética, Consejo Superior de Investigaciones Científicas/Universidad de Salamanca, Salamanca, Spain
| | - M Belén Moreno
- Instituto de Biología Funcional y Genómica and Departamento de Microbiología y Genética, Consejo Superior de Investigaciones Científicas/Universidad de Salamanca, Salamanca, Spain
| | - José Ángel Clemente-Ramos
- Instituto de Biología Funcional y Genómica and Departamento de Microbiología y Genética, Consejo Superior de Investigaciones Científicas/Universidad de Salamanca, Salamanca, Spain
| | - Masako Osumi
- Laboratory of Electron Microscopy/Bio-imaging Center, Japan Women's University, Bunkyo-ku, Tokyo, Japan.,Integrated Imaging Research Support, Chiyoda-ku, Tokyo, Japan
| | - Pilar Pérez
- Instituto de Biología Funcional y Genómica and Departamento de Microbiología y Genética, Consejo Superior de Investigaciones Científicas/Universidad de Salamanca, Salamanca, Spain
| | - Juan Carlos Ribas
- Instituto de Biología Funcional y Genómica and Departamento de Microbiología y Genética, Consejo Superior de Investigaciones Científicas/Universidad de Salamanca, Salamanca, Spain
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11
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Pérez P, Soto T, Gómez-Gil E, Cansado J. Functional interaction between Cdc42 and the stress MAPK signaling pathway during the regulation of fission yeast polarized growth. Int Microbiol 2019; 23:31-41. [PMID: 30989357 DOI: 10.1007/s10123-019-00072-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 03/18/2019] [Accepted: 03/20/2019] [Indexed: 12/12/2022]
Abstract
Cell polarization can be defined as the generation and maintenance of directional cellular organization. The spatial distribution and protein or lipid composition of the cell are not symmetric but organized in specialized domains which allow cells to grow and acquire a certain shape that is closely linked to their physiological function. The establishment and maintenance of polarized growth requires the coordination of diverse processes including cytoskeletal dynamics, membrane trafficking, and signaling cascade regulation. Some of the major players involved in the selection and maintenance of sites for polarized growth are Rho GTPases, which recognize the polarization site and transmit the signal to regulatory proteins of the cytoskeleton. Additionally, cytoskeletal organization, polarized secretion, and endocytosis are controlled by signaling pathways including those mediated by mitogen-activated protein kinases (MAPKs). Rho GTPases and the MAPK signaling pathways are strongly conserved from yeast to mammals, suggesting that the basic mechanisms of polarized growth have been maintained throughout evolution. For this reason, the study of how polarized growth is established and regulated in simple organisms such as the fission yeast Schizosaccharomyces pombe has contributed to broaden our knowledge about these processes in multicellular organisms. We review here the function of the Cdc42 GTPase and the stress activated MAPK (SAPK) signaling pathways during fission yeast polarized growth, and discuss the relevance of the crosstalk between both pathways.
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Affiliation(s)
- Pilar Pérez
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas and Universidad de Salamanca, 37007, Salamanca, Spain.
| | - Teresa Soto
- Yeast Physiology Group, Department of Genetics and Microbiology, Facultad de Biología, Universidad de Murcia, 30071, Murcia, Spain
| | - Elisa Gómez-Gil
- Yeast Physiology Group, Department of Genetics and Microbiology, Facultad de Biología, Universidad de Murcia, 30071, Murcia, Spain
| | - Jose Cansado
- Yeast Physiology Group, Department of Genetics and Microbiology, Facultad de Biología, Universidad de Murcia, 30071, Murcia, Spain.
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12
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Pérez P, Cortés JC, Cansado J, Ribas JC. Fission yeast cell wall biosynthesis and cell integrity signalling. ACTA ACUST UNITED AC 2018; 4:1-9. [PMID: 32743131 PMCID: PMC7388972 DOI: 10.1016/j.tcsw.2018.10.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 10/04/2018] [Accepted: 10/09/2018] [Indexed: 02/02/2023]
Abstract
The cell wall is a structure external to the plasma membrane that is essential for the survival of the fungi. This polysaccharidic structure confers resistance to the cell internal turgor pressure and protection against mechanical injury. The fungal wall is also responsible for the shape of these organisms due to different structural polysaccharides, such as β-(1,3)-glucan, which form fibers and confer rigidity to the cell wall. These polysaccharides are not present in animal cells and therefore they constitute excellent targets for antifungal chemotherapies. Cell wall damage leads to the activation of MAPK signaling pathways, which respond to the damage by activating the repair of the wall and the maintenance of the cell integrity. Fission yeast Schizosaccharomyces pombe is a model organism for the study morphogenesis, cell wall, and how different inputs might regulate this structure. We present here a short overview of the fission yeast wall composition and provide information about the main biosynthetic activities that assemble this cell wall. Additionally, we comment the recent advances in the knowledge of the cell wall functions and discuss the role of the cell integrity MAPK signaling pathway in the regulation of fission yeast wall.
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Affiliation(s)
- Pilar Pérez
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas and Universidad de Salamanca, 37007 Salamanca, Spain
- Corresponding author.
| | - Juan C.G. Cortés
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas and Universidad de Salamanca, 37007 Salamanca, Spain
| | - Jose Cansado
- Yeast Physiology Group, Department of Genetics and Microbiology, Facultad de Biología, Universidad de Murcia, 30071 Murcia, Spain
| | - Juan C. Ribas
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas and Universidad de Salamanca, 37007 Salamanca, Spain
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13
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Sepúlveda-Ramírez SP, Toledo-Jacobo L, Henson JH, Shuster CB. Cdc42 controls primary mesenchyme cell morphogenesis in the sea urchin embryo. Dev Biol 2018; 437:140-151. [PMID: 29555242 PMCID: PMC5973877 DOI: 10.1016/j.ydbio.2018.03.015] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 03/05/2018] [Accepted: 03/15/2018] [Indexed: 12/15/2022]
Abstract
In the sea urchin embryo, gastrulation is characterized by the ingression and directed cell migration of primary mesenchyme cells (PMCs), as well as the primary invagination and convergent extension of the endomesoderm. Like all cell shape changes, individual and collective cell motility is orchestrated by Rho family GTPases and their modulation of the actomyosin cytoskeleton. And while endomesoderm specification has been intensively studied in echinoids, much less is known about the proximate regulators driving cell motility. Toward these ends, we employed anti-sense morpholinos, mutant alleles and pharmacological inhibitors to assess the role of Cdc42 during sea urchin gastrulation. While inhibition of Cdc42 expression or activity had only mild effects on PMC ingression, PMC migration, alignment and skeletogenesis were disrupted in the absence of Cdc42, as well as elongation of the archenteron. PMC migration and patterning of the larval skeleton relies on the extension of filopodia, and Cdc42 was required for filopodia in vivo as well as in cultured PMCs. Lastly, filopodial extension required both Arp2/3 and formin actin-nucleating factors, supporting models of filopodial nucleation observed in other systems. Together, these results suggest that Cdc42 plays essential roles during PMC cell motility and organogenesis.
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Affiliation(s)
- Silvia P Sepúlveda-Ramírez
- Department of Biology, New Mexico State University, Las Cruces, NM 88003, United States; University of Washington Friday Harbor Laboratories, Friday Harbor, WA 98250, United States
| | - Leslie Toledo-Jacobo
- Department of Biology, New Mexico State University, Las Cruces, NM 88003, United States; University of Washington Friday Harbor Laboratories, Friday Harbor, WA 98250, United States
| | - John H Henson
- University of Washington Friday Harbor Laboratories, Friday Harbor, WA 98250, United States; Department of Biology, Dickinson College, Carlisle, PA 17013, United States
| | - Charles B Shuster
- Department of Biology, New Mexico State University, Las Cruces, NM 88003, United States; University of Washington Friday Harbor Laboratories, Friday Harbor, WA 98250, United States.
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14
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Estravís M, Rincón SA, Portales E, Pérez P, Santos B. Cdc42 activation state affects its localization and protein levels in fission yeast. MICROBIOLOGY-SGM 2017; 163:1156-1166. [PMID: 28742002 DOI: 10.1099/mic.0.000503] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Rho GTPases control polarized cell growth and are well-known regulators of exocytic and endocytic processes. Cdc42 is an essential GTPase, conserved from yeast to humans, that is critical for cell polarization. Cdc42 is negatively regulated by the GTPase-activating proteins (GAPs) and the GDP dissociation inhibitors (GDIs), and positively regulated by guanine nucleotide exchange factors (GEFs). Cdc42 GTPase can be found in a GTP- or GDP-bound state, which determines the ability to bind downstream effector proteins and activate signalling pathways. Only GTP-bound Cdc42 is active. In this study we have analysed the localization of the different nucleotide-bound states of Cdc42 in Schizosaccharomyces pombe: the wild-type Cdc42 protein that cycles between an active and inactive form, the Cdc42G12V form that is permanently bound to GTP and the Cdc42T17N form that is constitutively inactive. Our results indicate that Cdc42 localizes to several membrane compartments in the cell and this localization is mediated by its C-terminal prenylation. Constitutively active Cdc42 localizes mainly to the plasma membrane and concentrates at the growing tips where it is considerably less dynamic than wild-type or GDP-bound Cdc42. Additionally we show that the activation state of Cdc42 also participates in the regulation of its protein levels mediated by endocytosis and by the exocyst complex.
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Affiliation(s)
- Miguel Estravís
- Instituto de Biología Funcional y Genómica (IBFG), Consejo Superior de Investigaciones Científicas, University of Salamanca, 37007 Salamanca, Spain
| | - Sergio Antonio Rincón
- Instituto de Biología Funcional y Genómica (IBFG), Consejo Superior de Investigaciones Científicas, University of Salamanca, 37007 Salamanca, Spain.,Present address: Institut Curie, Centre de Recherche, PSL Research University, CNRS UMR144, F-75248 Paris, France
| | - Elvira Portales
- Instituto de Biología Funcional y Genómica (IBFG), Consejo Superior de Investigaciones Científicas, University of Salamanca, 37007 Salamanca, Spain
| | - Pilar Pérez
- 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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15
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Franco A, Soto T, Martín-García R, Madrid M, Vázquez-Marín B, Vicente-Soler J, Coll PM, Gacto M, Pérez P, Cansado J. Distinct functional relevance of dynamic GTPase cysteine methylation in fission yeast. Sci Rep 2017; 7:6057. [PMID: 28729673 PMCID: PMC5519673 DOI: 10.1038/s41598-017-06053-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 06/07/2017] [Indexed: 12/11/2022] Open
Abstract
The final step in post-translational processing of Ras and Rho GTPases involves methylation of the prenylated cysteine residue by an isoprenylcysteine-O-carboxyl methyltransferase (ICMT). ICMT activity is essential for cell growth and development in higher eukaryotes, and inhibition of GTPase methylation has become an attractive target in cancer therapy to inactivate prenylated oncoproteins. However, the specificity and dynamics of the GTPase methylation process remain to be fully clarified. Notably, cells lacking Mam4, the ICMT ortholog in the fission yeast Schizosaccharomyces pombe, are viable. We have exploited this feature to analyze the role of methylation on GTPase localization and function. We show that methylation differentially affects GTPase membrane localization, being particularly relevant for plasma membrane tethering and downstream signaling of palmitoylated and farnesylated GTPases Ras1 and Rho2 lacking C-terminal polybasic motifs. Indeed, Ras1 and Rho2 cysteine methylation is required for proper regulation of differentiation elicited by MAPK Spk1 and for stress-dependent activation of the cell integrity pathway (CIP) and its main effector MAPK Pmk1. Further, Mam4 negatively regulates TORC2 signaling by a cross-inhibitory mechanism relying on Rho GTPase methylation. These results highlight the requirement for a tight control of GTPase methylation in vivo to allow adequate GTPase function.
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Affiliation(s)
- Alejandro Franco
- Yeast Physiology Group, Department of Genetics and Microbiology, Facultad de Biología, Universidad de Murcia, 30071, Murcia, Spain
| | - Teresa Soto
- Yeast Physiology Group, Department of Genetics and Microbiology, Facultad de Biología, Universidad de Murcia, 30071, Murcia, Spain
| | - Rebeca Martín-García
- Instituto de Biología Funcional y Genómica (IBFG), Consejo Superior de Investigaciones Científicas/Departamento de Microbiología y Genética, Universidad de Salamanca, 37007, Salamanca, Spain
| | - Marisa Madrid
- Yeast Physiology Group, Department of Genetics and Microbiology, Facultad de Biología, Universidad de Murcia, 30071, Murcia, Spain
| | - Beatriz Vázquez-Marín
- Yeast Physiology Group, Department of Genetics and Microbiology, Facultad de Biología, Universidad de Murcia, 30071, Murcia, Spain
| | - Jero Vicente-Soler
- Yeast Physiology Group, Department of Genetics and Microbiology, Facultad de Biología, Universidad de Murcia, 30071, Murcia, Spain
| | - Pedro M Coll
- Instituto de Biología Funcional y Genómica (IBFG), Consejo Superior de Investigaciones Científicas/Departamento de Microbiología y Genética, Universidad de Salamanca, 37007, Salamanca, Spain
| | - Mariano Gacto
- Yeast Physiology Group, Department of Genetics and Microbiology, Facultad de Biología, Universidad de Murcia, 30071, Murcia, Spain
| | - Pilar Pérez
- Instituto de Biología Funcional y Genómica (IBFG), Consejo Superior de Investigaciones Científicas/Departamento de Microbiología y Genética, Universidad de Salamanca, 37007, Salamanca, Spain
| | - José Cansado
- Yeast Physiology Group, Department of Genetics and Microbiology, Facultad de Biología, Universidad de Murcia, 30071, Murcia, Spain.
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16
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Haupt A, Minc N. Gradients of phosphatidylserine contribute to plasma membrane charge localization and cell polarity in fission yeast. Mol Biol Cell 2016; 28:210-220. [PMID: 27852900 PMCID: PMC5221626 DOI: 10.1091/mbc.e16-06-0353] [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: 06/02/2016] [Revised: 11/07/2016] [Accepted: 11/08/2016] [Indexed: 12/19/2022] Open
Abstract
Surface charges at the inner leaflet of the plasma membrane may contribute to regulate the surface recruitment of key signaling factors. Phosphatidylserine (PS) is an abundant charged lipid that may regulate charge distribution in different cell types. Here we characterize the subcellular distribution and function of PS in the rod-shaped, polarized fission yeast. We find that PS preferably accumulates at cell tips and defines a gradient of negative charges along the cell surface. This polarization depends on actin-mediated endocytosis and contributes to the subcellular partitioning of charged polarity-regulating Rho GTPases like Rho1 or Cdc42 in a protein charge-dependent manner. Cells depleted of PS have altered cell dimensions and fail to properly regulate growth from the second end, suggesting a role for PS and membrane charge in polarized cell growth.
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Affiliation(s)
- Armin Haupt
- Institut Jacques Monod, 75205 Paris Cedex 13, France
| | - Nicolas Minc
- Institut Jacques Monod, 75205 Paris Cedex 13, France
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17
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Merlini L, Khalili B, Bendezú FO, Hurwitz D, Vincenzetti V, Vavylonis D, Martin SG. Local Pheromone Release from Dynamic Polarity Sites Underlies Cell-Cell Pairing during Yeast Mating. Curr Biol 2016; 26:1117-25. [PMID: 27020743 DOI: 10.1016/j.cub.2016.02.064] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Revised: 02/01/2016] [Accepted: 02/25/2016] [Indexed: 11/19/2022]
Abstract
Cell pairing is central for many processes, including immune defense, neuronal connection, hyphal fusion, and sexual reproduction. How does a cell orient toward a partner, especially when faced with multiple choices? Fission yeast Schizosaccharomyces pombe P and M cells, which respectively express P and M factor pheromones [1, 2], pair during the mating process induced by nitrogen starvation. Engagement of pheromone receptors Map3 and Mam2 [3, 4] with their cognate pheromone ligands leads to activation of the Gα protein Gpa1 to signal sexual differentiation [3, 5, 6]. Prior to cell pairing, the Cdc42 GTPase, a central regulator of cell polarization, forms dynamic zones of activity at the cell periphery at distinct locations over time [7]. Here we show that Cdc42-GTP polarization sites contain the M factor transporter Mam1, the general secretion machinery, which underlies P factor secretion, and Gpa1, suggesting that these are sub-cellular zones of pheromone secretion and signaling. Zone lifetimes scale with pheromone concentration. Computational simulations of pair formation through a fluctuating zone show that the combination of local pheromone release and sensing, short pheromone decay length, and pheromone-dependent zone stabilization leads to efficient pair formation. Consistently, pairing efficiency is reduced in the absence of the P factor protease. Similarly, zone stabilization at reduced pheromone levels, which occurs in the absence of the predicted GTPase-activating protein for Ras, leads to reduction in pairing efficiency. We propose that efficient cell pairing relies on fluctuating local signal emission and perception, which become locked into place through stimulation.
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Affiliation(s)
- Laura Merlini
- Department of Fundamental Microbiology, University of Lausanne, Biophore Building, 1015 Lausanne, Switzerland
| | - Bita Khalili
- Department of Physics, Lehigh University, Bethlehem, PA 18015, USA
| | - Felipe O Bendezú
- Department of Fundamental Microbiology, University of Lausanne, Biophore Building, 1015 Lausanne, Switzerland
| | - Daniel Hurwitz
- Department of Physics, Lehigh University, Bethlehem, PA 18015, USA; Department of Physics, University of Texas at Austin, Austin, TX 78712, USA
| | - Vincent Vincenzetti
- Department of Fundamental Microbiology, University of Lausanne, Biophore Building, 1015 Lausanne, Switzerland
| | | | - Sophie G Martin
- Department of Fundamental Microbiology, University of Lausanne, Biophore Building, 1015 Lausanne, Switzerland.
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18
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Revilla-Guarinos MT, Martín-García R, Villar-Tajadura MA, Estravís M, Coll PM, Pérez P. Rga6 is a Fission Yeast Rho GAP Involved in Cdc42 Regulation of Polarized Growth. Mol Biol Cell 2016; 27:mbc.E15-12-0818. [PMID: 26960792 PMCID: PMC4850039 DOI: 10.1091/mbc.e15-12-0818] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Revised: 03/03/2016] [Accepted: 03/04/2016] [Indexed: 11/15/2022] Open
Abstract
Active Cdc42 is essential for the establishment of polarized growth. This GTPase is negatively regulated by the GTPase-activating proteins (GAPs), which are important for the spatial specificity of Cdc42 function. Rga4 is the only GAP described as negative regulator of fission yeast Cdc42. We report here that Rga6 is another fission yeast Cdc42 GAP which shares some functions with Rga4. Cells lacking Rga6 are viable but slightly shorter and broader than wild type, and cells lacking Rga6 and Rga4 simultaneously are rounded. In these cells, active Cdc42 is observed all around the membrane. These additive effects indicate that both GAPs collaborate in the spatial regulation of active Cdc42. Rga6 localizes to the plasma membrane forming clusters different from those formed by Rga4. A polybasic region at the Rga6 C-terminus is responsible for its membrane localization. Rga6-GFP fluorescence decreases considerably at the growing tips, and this decrease is dependent on the actin cables. Notably, in the absence of Rga6 the amplitude of active Cdc42 oscillations at the tips decreases, and less GTP-Cdc42 accumulates at the new end of the cells. We propose here that Rga6 collaborates with Rga4 to spatially restrict active Cdc42 at the cell tips and maintain cell dimensions.
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Affiliation(s)
- M Teresa Revilla-Guarinos
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas (CSIC) / Departamento de Microbiología y Genética, Universidad de Salamanca. Salamanca, Spain
| | - Rebeca Martín-García
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas (CSIC) / Departamento de Microbiología y Genética, Universidad de Salamanca. Salamanca, Spain
| | - M Antonia Villar-Tajadura
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas (CSIC) / Departamento de Microbiología y Genética, Universidad de Salamanca. Salamanca, Spain
| | - Miguel Estravís
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas (CSIC) / Departamento de Microbiología y Genética, Universidad de Salamanca. Salamanca, Spain
| | - Pedro M Coll
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas (CSIC) / Departamento de Microbiología y Genética, Universidad de Salamanca. Salamanca, Spain
| | - Pilar Pérez
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas (CSIC) / Departamento de Microbiología y Genética, Universidad de Salamanca. Salamanca, Spain
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19
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Wei B, Hercyk BS, Mattson N, Mohammadi A, Rich J, DeBruyne E, Clark MM, Das M. Unique spatiotemporal activation pattern of Cdc42 by Gef1 and Scd1 promotes different events during cytokinesis. Mol Biol Cell 2016; 27:1235-45. [PMID: 26941334 PMCID: PMC4831878 DOI: 10.1091/mbc.e15-10-0700] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 02/23/2016] [Indexed: 11/11/2022] Open
Abstract
The Rho-family GTPase Cdc42 regulates cell polarity and localizes to the cell division site. Cdc42 is activated by guanine nucleotide exchange factors (GEFs). We report that Cdc42 promotes cytokinesis via a unique spatiotemporal activation pattern due to the distinct action of its GEFs, Gef1 and Scd1, in fission yeast. Before cytokinetic ring constriction, Cdc42 activation, is Gef1 dependent, and after ring constriction, it is Scd1 dependent. Gef1 localizes to the actomyosin ring immediately after ring assembly and promotes timely onset of ring constriction. Gef1 is required for proper actin organization during cytokinesis, distribution of type V myosin Myo52 to the division site, and timely recruitment of septum protein Bgs1. In contrast, Scd1 localizes to the broader region of ingressing membrane during cytokinetic furrowing. Scd1 promotes normal septum formation, andscd1Δcells display aberrant septa with reduced Bgs1 localization. Thus we define unique roles of the GEFs Gef1 and Scd1 in the regulation of distinct events during cytokinesis. Gef1 localizes first to the cytokinetic ring and promotes timely constriction, whereas Scd1 localizes later to the ingressing membrane and promotes septum formation. Our findings are consistent with reports that complexity in GTPase signaling patterns enables exquisite precision over the control of cellular processes.
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Affiliation(s)
- Bin Wei
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996
| | - Brian S Hercyk
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996
| | - Nicholas Mattson
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996
| | - Ahmad Mohammadi
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996
| | - Julie Rich
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996
| | - Erica DeBruyne
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996
| | - Mikayla M Clark
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996
| | - Maitreyi Das
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996
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20
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Beckley JR, Chen JS, Yang Y, Peng J, Gould KL. A Degenerate Cohort of Yeast Membrane Trafficking DUBs Mediates Cell Polarity and Survival. Mol Cell Proteomics 2015; 14:3132-41. [PMID: 26412298 DOI: 10.1074/mcp.m115.050039] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Indexed: 12/26/2022] Open
Abstract
Deubiquitinating enzymes (DUBs), cysteine or metallo- proteases that cleave ubiquitin chains or protein conjugates, are present in nearly every cellular compartment, with overlapping protein domain structure, localization, and functions. We discovered a cohort of DUBs that are involved in membrane trafficking (ubp4, ubp5, ubp9, ubp15, and sst2) and found that loss of all five of these DUBs but not loss of any combination of four, significantly impacted cell viability in the fission yeast Schizosaccharomyces pombe (1). Here, we delineate the collective and individual functions and activities of these five conserved DUBs using comparative proteomics, biochemistry, and microscopy. We find these five DUBs are degenerate rather than redundant at the levels of cell morphology, substrate selectivity, ubiquitin chain specificity, and cell viability under stress. These studies reveal the complexity of interplay among these enzymes, providing a foundation for understanding DUB biology and providing another example of how cells utilize degeneracy to improve survival.
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Affiliation(s)
- Janel R Beckley
- From the Cell & Developmental Biology, Vanderbilt University School of Medicine, 1161 21st Avenue South, Nashville, TN 37232
| | - Jun-Song Chen
- From the Cell & Developmental Biology, Vanderbilt University School of Medicine, 1161 21st Avenue South, Nashville, TN 37232
| | - Yanling Yang
- Departments of Structural Biology and Developmental Neurobiology, St. Jude Proteomics Facility, St. Jude Children's Research Hospital, Memphis, TN 38105
| | - Junmin Peng
- Departments of Structural Biology and Developmental Neurobiology, St. Jude Proteomics Facility, St. Jude Children's Research Hospital, Memphis, TN 38105
| | - Kathleen L Gould
- From the Cell & Developmental Biology, Vanderbilt University School of Medicine, 1161 21st Avenue South, Nashville, TN 37232
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21
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Das M, Nuñez I, Rodriguez M, Wiley DJ, Rodriguez J, Sarkeshik A, Yates JR, Buchwald P, Verde F. Phosphorylation-dependent inhibition of Cdc42 GEF Gef1 by 14-3-3 protein Rad24 spatially regulates Cdc42 GTPase activity and oscillatory dynamics during cell morphogenesis. Mol Biol Cell 2015; 26:3520-34. [PMID: 26246599 PMCID: PMC4591695 DOI: 10.1091/mbc.e15-02-0095] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Accepted: 07/30/2015] [Indexed: 11/25/2022] Open
Abstract
The 14-3-3 protein Rad24 modulates the availability of Cdc42 GEF Gef1, spatially regulating Cdc42 activity during cell morphogenesis. Gef1 is sequestered in the cytoplasm upon 14-3-3 interaction, mediated by Orb6 kinase. The resulting competition for Gef1 promotes anticorrelated Cdc42 oscillations at cell tips. Active Cdc42 GTPase, a key regulator of cell polarity, displays oscillatory dynamics that are anticorrelated at the two cell tips in fission yeast. Anticorrelation suggests competition for active Cdc42 or for its effectors. Here we show how 14-3-3 protein Rad24 associates with Cdc42 guanine exchange factor (GEF) Gef1, limiting Gef1 availability to promote Cdc42 activation. Phosphorylation of Gef1 by conserved NDR kinase Orb6 promotes Gef1 binding to Rad24. Loss of Rad24–Gef1 interaction increases Gef1 protein localization and Cdc42 activation at the cell tips and reduces the anticorrelation of active Cdc42 oscillations. Increased Cdc42 activation promotes precocious bipolar growth activation, bypassing the normal requirement for an intact microtubule cytoskeleton and for microtubule-dependent polarity landmark Tea4-PP1. Further, increased Cdc42 activation by Gef1 widens cell diameter and alters tip curvature, countering the effects of Cdc42 GTPase-activating protein Rga4. The respective levels of Gef1 and Rga4 proteins at the membrane define dynamically the growing area at each cell tip. Our findings show how the 14-3-3 protein Rad24 modulates the availability of Cdc42 GEF Gef1, a homologue of mammalian Cdc42 GEF DNMBP/TUBA, to spatially control Cdc42 GTPase activity and promote cell polarization and cell shape emergence.
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Affiliation(s)
- Maitreyi Das
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL 33101
| | - Illyce Nuñez
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL 33101
| | - Marbelys Rodriguez
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL 33101
| | - David J Wiley
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL 33101
| | - Juan Rodriguez
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL 33101
| | - Ali Sarkeshik
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL 33101
| | - John R Yates
- Department of Chemical Physiology, Scripps Research Institute, La Jolla, CA 92037
| | - Peter Buchwald
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL 33101
| | - Fulvia Verde
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL 33101 Marine Biological Laboratory, Woods Hole, MA 02543. )
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22
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Arasada R, Pollard TD. A role for F-BAR protein Rga7p during cytokinesis in S. pombe. J Cell Sci 2015; 128:2259-68. [PMID: 25977474 DOI: 10.1242/jcs.162974] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2014] [Accepted: 05/07/2015] [Indexed: 12/22/2022] Open
Abstract
F-BAR proteins are known to participate in cytokinesis, but their mechanisms are not well understood. Here we investigated Rga7p, an Schizosaccharomyces pombe F-BAR protein with a RhoGAP domain. Localization of Rga7p to the cytokinetic cleavage furrow depends on its F-BAR domain, actin filaments, the formins Cdc12p and For3p, and the presence of a contractile ring. Rga7p is not required for the constriction of the contractile ring but does participate in the transport of a β-glucan synthetase (Bgs4p) from the late Golgi compartments to plasma membrane that is adjacent to the contractile ring. Cells without Rga7p moved Bgs4p normally from the poles to the Golgi complex near to the cell center, but Bgs4p then moved slowly from the late Golgi compartments to the cleavage site. The late arrival and lower than normal numbers of Bgs4p result in septal defects late in cytokinesis, and in the lysis of separating cells, similar to that in cells with mutations in the cwg1(+) gene (which encodes Bgs4p).
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Affiliation(s)
- Rajesh Arasada
- Department of Molecular Cellular and Developmental Biology, Yale University, PO Box 208103, New Haven, CT 06520-8103, USA
| | - Thomas D Pollard
- Department of Molecular Cellular and Developmental Biology, Yale University, PO Box 208103, New Haven, CT 06520-8103, USA Department of Molecular Biophysics and Biochemistry, Yale University, PO Box 208103, New Haven, CT 06520-8103, USA Department of Cell Biology, Yale University, PO Box 208103, New Haven, CT 06520-8103, USA
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23
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Bai Z, Grant BD. A TOCA/CDC-42/PAR/WAVE functional module required for retrograde endocytic recycling. Proc Natl Acad Sci U S A 2015; 112:E1443-52. [PMID: 25775511 PMCID: PMC4378436 DOI: 10.1073/pnas.1418651112] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Endosome-to-Golgi transport is required for the function of many key membrane proteins and lipids, including signaling receptors, small-molecule transporters, and adhesion proteins. The retromer complex is well-known for its role in cargo sorting and vesicle budding from early endosomes, in most cases leading to cargo fusion with the trans-Golgi network (TGN). Transport from recycling endosomes to the TGN has also been reported, but much less is understood about the molecules that mediate this transport step. Here we provide evidence that the F-BAR domain proteins TOCA-1 and TOCA-2 (Transducer of Cdc42 dependent actin assembly), the small GTPase CDC-42 (Cell division control protein 42), associated polarity proteins PAR-6 (Partitioning defective 6) and PKC-3/atypical protein kinase C, and the WAVE actin nucleation complex mediate the transport of MIG-14/Wls and TGN-38/TGN38 cargo proteins from the recycling endosome to the TGN in Caenorhabditis elegans. Our results indicate that CDC-42, the TOCA proteins, and the WAVE component WVE-1 are enriched on RME-1-positive recycling endosomes in the intestine, unlike retromer components that act on early endosomes. Furthermore, we find that retrograde cargo TGN-38 is trapped in early endosomes after depletion of SNX-3 (a retromer component) but is mainly trapped in recycling endosomes after depletion of CDC-42, indicating that the CDC-42-associated complex functions after retromer in a distinct organelle. Thus, we identify a group of interacting proteins that mediate retrograde recycling, and link these proteins to a poorly understood trafficking step, recycling endosome-to-Golgi transport. We also provide evidence for the physiological importance of this pathway in WNT signaling.
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Affiliation(s)
- Zhiyong Bai
- Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, NJ 08854
| | - Barth D Grant
- Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, NJ 08854
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Pérez P, Portales E, Santos B. Rho4 interaction with exocyst and septins regulates cell separation in fission yeast. MICROBIOLOGY-SGM 2015; 161:948-959. [PMID: 25724972 DOI: 10.1099/mic.0.000062] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Accepted: 02/18/2015] [Indexed: 12/17/2022]
Abstract
Rho GTPases are small proteins present in all eukaryotic cells, from yeast to mammals, with a function in actin organization and morphogenetic processes. Schizosaccharomyces pombe Rho4 is not essential but it displays a role during cell separation at high temperature. In fact, Rho4 is involved in the secretion of the hydrolytic enzymes that are required for cell septum degradation during this process. In rho4Δ cells, vesicles accumulate in the septum area and the glucanases Eng1 and Agn1 are not secreted to the culture medium. The localization of Eng1 and Agn1 depends on the exocyst and the septins. The exocyst is a conserved multiprotein complex important for the targeting and fusion of Golgi-derived vesicles with the plasma membrane. Septins are a family of GTP-binding proteins conserved in eukaryotes that function during cytokinesis. Here we show that Rho4 is required for the proper localization of the exocyst and septins at high temperature. Moreover, pull-down experiments demonstrate that Rho4 can interact with exocyst subunits, such as Sec8 and Exo70, and septin proteins, such as Spn3. We observe that Sec8 preferentially binds to activated GTP-Rho4, suggesting that Sec8 could be an effector of this GTPase. We propose that the interaction of Rho4 with the exocyst and septins confers a precise regulation for the secretion of glucanases at the appropriate place and time during the cell cycle.
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Affiliation(s)
- Pilar Pérez
- Instituto de Biología Funcional y Genómica (IBFG), CSIC/Universidad de Salamanca, Avd. Zacarías González s/n, 37007 Salamanca, Spain
| | - Elvira Portales
- Instituto de Biología Funcional y Genómica (IBFG), CSIC/Universidad de Salamanca, Avd. Zacarías González s/n, 37007 Salamanca, Spain
| | - Beatriz Santos
- Departamento de Microbiología y Genética, Universidad de Salamanca, Avd. Zacarías González s/n, 37007 Salamanca, Spain.,Instituto de Biología Funcional y Genómica (IBFG), CSIC/Universidad de Salamanca, Avd. Zacarías González s/n, 37007 Salamanca, Spain
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25
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Doi A, Kita A, Kanda Y, Uno T, Asami K, Satoh R, Nakano K, Sugiura R. Geranylgeranyltransferase Cwg2-Rho4/Rho5 module is implicated in the Pmk1 MAP kinase-mediated cell wall integrity pathway in fission yeast. Genes Cells 2015; 20:310-23. [DOI: 10.1111/gtc.12222] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2014] [Accepted: 12/15/2014] [Indexed: 11/27/2022]
Affiliation(s)
- Akira Doi
- Laboratory of Molecular Pharmacogenomics; School of Pharmaceutical Sciences; Kinki University; Kowakae 3-4-1 Higashi-Osaka 577-8502 Japan
- Japan Society for the Promotion of Science; 1-8 Chiyoda-ku Tokyo 102-8472 Japan
| | - Ayako Kita
- Laboratory of Molecular Pharmacogenomics; School of Pharmaceutical Sciences; Kinki University; Kowakae 3-4-1 Higashi-Osaka 577-8502 Japan
| | - Yuki Kanda
- Laboratory of Molecular Pharmacogenomics; School of Pharmaceutical Sciences; Kinki University; Kowakae 3-4-1 Higashi-Osaka 577-8502 Japan
| | - Takaya Uno
- Laboratory of Molecular Pharmacogenomics; School of Pharmaceutical Sciences; Kinki University; Kowakae 3-4-1 Higashi-Osaka 577-8502 Japan
| | - Keita Asami
- Laboratory of Molecular Pharmacogenomics; School of Pharmaceutical Sciences; Kinki University; Kowakae 3-4-1 Higashi-Osaka 577-8502 Japan
| | - Ryosuke Satoh
- Laboratory of Molecular Pharmacogenomics; School of Pharmaceutical Sciences; Kinki University; Kowakae 3-4-1 Higashi-Osaka 577-8502 Japan
| | - Kentaro Nakano
- Department of Biological Sciences; Graduate School of Life and Environmental Sciences; University of Tsukuba; 1-1-1 Tennohdai Tsukuba Ibaraki 305-8577 Japan
| | - Reiko Sugiura
- Laboratory of Molecular Pharmacogenomics; School of Pharmaceutical Sciences; Kinki University; Kowakae 3-4-1 Higashi-Osaka 577-8502 Japan
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26
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Nishimura S, Tokukura M, Ochi J, Yoshida M, Kakeya H. Balance between exocytosis and endocytosis determines the efficacy of sterol-targeting antibiotics. ACTA ACUST UNITED AC 2014; 21:1690-9. [PMID: 25500221 DOI: 10.1016/j.chembiol.2014.10.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Revised: 09/26/2014] [Accepted: 10/30/2014] [Indexed: 02/03/2023]
Abstract
Antifungals targeting membrane ergosterol are longstanding, yet indispensable drugs in clinical use. However, the mechanisms by which the cellular membrane domains recognized by these antibiotics are generated remain largely unknown. Here, we demonstrate that the balance between endocytosis and exocytosis in membrane trafficking is a critical factor in the action of sterol-targeting antibiotics. When fission yeast cells were treated with manumycin A, cellular binding and the action of the antifungals filipin, amphotericin B, and theonellamides, all of which are ergosterol-binders, were abolished. Additionally, manumycin A treatment attenuated Cdc42 activity and inhibited exocytosis, while endocytosis was only moderately suppressed. Similar defects in membrane trafficking could be reproduced by heat shock and genetic perturbation, which also abolished the action of the antibiotics. We propose that exocytosis and endocytosis respectively supply and internalize the specific plasma membrane domains recognized by sterol-targeting antibiotics.
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Affiliation(s)
- Shinichi Nishimura
- Division of Bioinformatics and Chemical Genomics, Department of System Chemotherapy and Molecular Sciences, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501, Japan.
| | - Masato Tokukura
- Division of Bioinformatics and Chemical Genomics, Department of System Chemotherapy and Molecular Sciences, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501, Japan
| | - Junko Ochi
- Division of Bioinformatics and Chemical Genomics, Department of System Chemotherapy and Molecular Sciences, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501, Japan
| | - Minoru Yoshida
- Chemical Genomics Research Group, RIKEN Center for Sustainable Resource Science, Wako, Saitama 351-0198, Japan
| | - Hideaki Kakeya
- Division of Bioinformatics and Chemical Genomics, Department of System Chemotherapy and Molecular Sciences, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501, Japan.
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27
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Oscillatory AAA+ ATPase Knk1 constitutes a novel morphogenetic pathway in fission yeast. Proc Natl Acad Sci U S A 2014; 111:17899-904. [PMID: 25422470 DOI: 10.1073/pnas.1407226111] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Cellular morphogenesis relies partly on cell polarization by the cytoskeleton. In the fission yeast Schizosaccharomyces pombe, it is well established that microtubules (MTs) deliver the spatial cue Tea1, a kelch repeat protein, to the tip regions to direct the growth machinery at the cell tips driving the linear extension of the rod-shaped organism to maintain a straight long axis. Here, we report the characterization of Knk1 (kink), a previously unidentified member of the superfamily of ATPases associated with various cellular activities (AAA(+)), whose deletion causes a unique morphological defect characterized by the formation of kinks close to cell tips. Through genetic analysis, we place Knk1 into a novel pathway controlling cell shape independently of MTs and Tea1. Knk1 localizes at cell tips. Its localization is mediated by the Knk1 N terminus and is enhanced upon ATP binding to the C-terminal ATPase domain. Furthermore, Knk1 tip recruitment is regulated by SRC-like adaptor 2 (Sla2) and cell division cycle 42 (Cdc42) independently of Sla2's role in endocytosis. Finally, we discovered that Knk1 shows an anticorrelated oscillatory behavior between the two cell tips at a periodicity that is different from the reported oscillatory Cdc42 dynamics.
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Zhang C, Hicks GR, Raikhel NV. Plant vacuole morphology and vacuolar trafficking. FRONTIERS IN PLANT SCIENCE 2014; 5:476. [PMID: 25309565 PMCID: PMC4173805 DOI: 10.3389/fpls.2014.00476] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Accepted: 08/29/2014] [Indexed: 05/23/2023]
Abstract
Plant vacuoles are essential organelles for plant growth and development, and have multiple functions. Vacuoles are highly dynamic and pleiomorphic, and their size varies depending on the cell type and growth conditions. Vacuoles compartmentalize different cellular components such as proteins, sugars, ions and other secondary metabolites and play critical roles in plants response to different biotic/abiotic signaling pathways. In this review, we will summarize the patterns of changes in vacuole morphology in certain cell types, our understanding of the mechanisms of plant vacuole biogenesis, and the role of SNAREs and Rab GTPases in vacuolar trafficking.
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Affiliation(s)
- Chunhua Zhang
- *Correspondence: Chunhua Zhang, Center for Plant Cell Biology and Department of Botany and Plant Sciences, University of California at Riverside, 900 University Avenue, Riverside, CA 92521, USA e-mail:
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29
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Abstract
Cell polarization is fundamental to many cellular processes, including cell differentiation, cell motility and cell fate determination. A key regulatory enzyme in the control of cell morphogenesis is the conserved Rho GTPase Cdc42, which breaks symmetry via self-amplifying positive-feedback mechanisms. Additional mechanisms of control, including competition between different sites of polarized cell growth and time-delayed negative feedback, define a cellular-level system that promotes Cdc42 oscillatory dynamics and modulates activated Cdc42 intracellular distribution.
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30
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Muñoz S, Manjón E, Sánchez Y. The putative exchange factor Gef3p interacts with Rho3p GTPase and the septin ring during cytokinesis in fission yeast. J Biol Chem 2014; 289:21995-2007. [PMID: 24947517 DOI: 10.1074/jbc.m114.548792] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The small GTP-binding proteins of the Rho family and its regulatory proteins play a central role in cytokinetic actomyosin ring assembly and cytokinesis. Here we show that the fission yeast guanine nucleotide exchange factor Gef3p interacts with Rho3p at the division site. Gef3p contains a putative DH homology domain and a BAR/IMD-like domain. The protein localized to the division site late in mitosis, where it formed a ring that did not constrict with actomyosin ring (cytokinetic actomyosin ring) invagination; instead, it split into a double ring that resembled the septin ring. Gef3p co-localized with septins and Mid2p and required septins and Mid2p for its localization. Gef3p interacts physically with the GTP-bound form of Rho3p. Although Gef3p is not essential for cell separation, the simultaneous disruption of gef3(+) and Rho3p-interacting proteins, such as Sec8p, an exocyst component, Apm1p, a subunit of the clathrin adaptor complex or For3p, an actin-polymerizing protein, yielded cells with strong defects in septation and polarity respectively. Our results suggest that interactions between septins and Rho-GEFs provide a new targeting mechanism for GTPases in cytokinesis, in this case probably contributing to Rho3p function in vesicle tethering and vesicle trafficking in the later steps of cell separation.
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Affiliation(s)
- Sofía Muñoz
- From the Instituto de Biología Funcional y Genómica (IBFG), Consejo Superior de Investigaciones Científicas and Departamento de Microbiología y Genética, Universidad de Salamanca, C/ Zacarías González, s/n. 37007 Salamanca, Spain
| | - Elvira Manjón
- From the Instituto de Biología Funcional y Genómica (IBFG), Consejo Superior de Investigaciones Científicas and Departamento de Microbiología y Genética, Universidad de Salamanca, C/ Zacarías González, s/n. 37007 Salamanca, Spain
| | - Yolanda Sánchez
- From the Instituto de Biología Funcional y Genómica (IBFG), Consejo Superior de Investigaciones Científicas and Departamento de Microbiología y Genética, Universidad de Salamanca, C/ Zacarías González, s/n. 37007 Salamanca, Spain
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31
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Jones TA, Nikolova LS, Schjelderup A, Metzstein MM. Exocyst-mediated membrane trafficking is required for branch outgrowth in Drosophila tracheal terminal cells. Dev Biol 2014; 390:41-50. [PMID: 24607370 DOI: 10.1016/j.ydbio.2014.02.021] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Revised: 02/19/2014] [Accepted: 02/20/2014] [Indexed: 11/16/2022]
Abstract
Branching morphogenesis, the process by which cells or tissues generate tree-like networks that function to increase surface area or in contacting multiple targets, is a common developmental motif in multicellular organisms. We use Drosophila tracheal terminal cells, a component of the insect respiratory system, to investigate branching morphogenesis that occurs at the single cell level. Here, we show that the exocyst, a conserved protein complex that facilitates docking and tethering of vesicles at the plasma membrane, is required for terminal cell branch outgrowth. We find that exocyst-deficient terminal cells have highly truncated branches and show an accumulation of vesicles within their cytoplasm and are also defective in subcellular lumen formation. We also show that vesicle trafficking pathways mediated by the Rab GTPases Rab10 and Rab11 are redundantly required for branch outgrowth. In terminal cells, the PAR-polarity complex is required for branching, and we find that the PAR complex is required for proper membrane localization of the exocyst, thus identifying a molecular link between the branching and outgrowth programs. Together, our results suggest a model where exocyst mediated vesicle trafficking facilitates branch outgrowth, while de novo branching requires cooperation between the PAR and exocyst complexes.
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Affiliation(s)
- Tiffani A Jones
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA
| | - Linda S Nikolova
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA
| | - Ani Schjelderup
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA
| | - Mark M Metzstein
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA.
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32
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Abstract
Polarized cell growth requires a well-orchestrated number of events, namely selection of growth site, organization of cytoskeleton elements and delivery of new material to the growth region. The small Rho GTPase Cdc42 has emerged as a major organizer of polarized growth through its participation in many of these events. In the present short review, we focus on the regulation of Cdc42 activity and localization as well as how it controls downstream events necessary for polarized cell growth in Schizosaccharomyces pombe. Owing to the high level of similarity of the polarity pathways, analogies between fission yeast and other model systems can be useful to decipher how cells can actively define their shape by polarized growth.
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33
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Yu Y, Li C, Kita A, Katayama Y, Kubouchi K, Udo M, Imanaka Y, Ueda S, Masuko T, Sugiura R. Sip1, an AP-1 accessory protein in fission yeast, is required for localization of Rho3 GTPase. PLoS One 2013; 8:e68488. [PMID: 23840894 PMCID: PMC3698097 DOI: 10.1371/journal.pone.0068488] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Accepted: 05/29/2013] [Indexed: 11/18/2022] Open
Abstract
Rho family GTPases act as molecular switches to regulate a range of physiological functions, including the regulation of the actin-based cytoskeleton, membrane trafficking, cell morphology, nuclear gene expression, and cell growth. Rho function is regulated by its ability to bind GTP and by its localization. We previously demonstrated functional and physical interactions between Rho3 and the clathrin-associated adaptor protein-1 (AP-1) complex, which revealed a role of Rho3 in regulating Golgi/endosomal trafficking in fission yeast. Sip1, a conserved AP-1 accessory protein, recruits the AP-1 complex to the Golgi/endosomes through physical interaction. In this study, we showed that Sip1 is required for Rho3 localization. First, overexpression of rho3⁺ suppressed defective membrane trafficking associated with sip1-i4 mutant cells, including defects in vacuolar fusion, Golgi/endosomal trafficking and secretion. Notably, Sip1 interacted with Rho3, and GFP-Rho3, similar to Apm1-GFP, did not properly localize to the Golgi/endosomes in sip1-i4 mutant cells at 27°C. Interestingly, the C-terminal region of Sip1 is required for its localization to the Golgi/endosomes, because Sip1-i4-GFP protein failed to properly localize to Golgi/endosomes, whereas the fluorescence of Sip1ΔN mutant protein co-localized with that of FM4-64. Consistently, in the sip1-i4 mutant cells, which lack the C-terminal region of Sip1, binding between Apm1 and Rho3 was greatly impaired, presumably due to mislocalization of these proteins in the sip1-i4 mutant cells. Furthermore, the interaction between Apm1 and Rho3 as well as Rho3 localization to the Golgi/endosomes were significantly rescued in sip1-i4 mutant cells by the expression of Sip1ΔN. Taken together, these results suggest that Sip1 recruits Rho3 to the Golgi/endosomes through physical interaction and enhances the formation of the Golgi/endosome AP-1/Rho3 complex, thereby promoting crosstalk between AP-1 and Rho3 in the regulation of Golgi/endosomal trafficking in fission yeast.
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Affiliation(s)
- Yang Yu
- Laboratory of Molecular Pharmacogenomics, School of Pharmaceutical Sciences, Kinki University, Kowakae, Higashi-Osaka, Japan
| | - Cuifang Li
- Laboratory of Molecular Pharmacogenomics, School of Pharmaceutical Sciences, Kinki University, Kowakae, Higashi-Osaka, Japan
- Japan Society for the Promotion of Science, Tokyo, Japan
| | - Ayako Kita
- Laboratory of Molecular Pharmacogenomics, School of Pharmaceutical Sciences, Kinki University, Kowakae, Higashi-Osaka, Japan
| | - Yuta Katayama
- Laboratory of Molecular Pharmacogenomics, School of Pharmaceutical Sciences, Kinki University, Kowakae, Higashi-Osaka, Japan
| | - Koji Kubouchi
- Laboratory of Molecular Pharmacogenomics, School of Pharmaceutical Sciences, Kinki University, Kowakae, Higashi-Osaka, Japan
| | - Masako Udo
- Laboratory of Molecular Pharmacogenomics, School of Pharmaceutical Sciences, Kinki University, Kowakae, Higashi-Osaka, Japan
| | - Yukako Imanaka
- Laboratory of Molecular Pharmacogenomics, School of Pharmaceutical Sciences, Kinki University, Kowakae, Higashi-Osaka, Japan
| | - Shiho Ueda
- Laboratory of Molecular Cell Biology, School of Pharmaceutical Sciences, Kinki University, Kowakae, Higashi-Osaka, Japan
| | - Takashi Masuko
- Laboratory of Molecular Cell Biology, School of Pharmaceutical Sciences, Kinki University, Kowakae, Higashi-Osaka, Japan
| | - Reiko Sugiura
- Laboratory of Molecular Pharmacogenomics, School of Pharmaceutical Sciences, Kinki University, Kowakae, Higashi-Osaka, Japan
- * E-mail:
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Abstract
How cells polarize in response to external cues is a fundamental biological problem. For mating, yeast cells orient growth toward the source of a pheromone gradient produced by cells of the opposite mating type. Polarized growth depends on the small GTPase Cdc42, a central eukaryotic polarity regulator that controls signaling, cytoskeleton polarization, and vesicle trafficking. However, the mechanisms of polarity establishment and mate selection in complex cellular environments are poorly understood. Here we show that, in fission yeast, low-level pheromone signaling promotes a novel polarization state, where active Cdc42, its GEF Scd1, and scaffold Scd2 form colocalizing dynamic zones that sample the periphery of the cell. Two direct Cdc42 effectors--actin cables marked by myosin V Myo52 and the exocyst complex labeled by Sec6 and Sec8--also dynamically colocalize with active Cdc42. However, these cells do not grow due to a block in the exocytosis of cell wall synthases Bgs1 and Bgs4. High-level pheromone stabilizes active Cdc42 zones and promotes cell wall synthase exocytosis and polarized growth. However, in the absence of prior low-level pheromone signaling, exploration fails, and cells polarize growth at cell poles by default. Consequently, these cells show altered partner choice, mating preferentially with sister rather than nonsister cells. Thus, Cdc42 exploration serves to orient growth for partner selection. This process may also promote genetic diversification.
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Affiliation(s)
- Felipe O Bendezú
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Biophore Building, 1015 Lausanne, Switzerland
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35
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Hachet O, Bendezú FO, Martin SG. Fission yeast: in shape to divide. Curr Opin Cell Biol 2012; 24:858-64. [PMID: 23127610 DOI: 10.1016/j.ceb.2012.10.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Revised: 09/27/2012] [Accepted: 10/02/2012] [Indexed: 01/27/2023]
Abstract
How are cell morphogenesis and cell cycle coordinated? The fission yeast is a rod-shaped unicellular organism widely used to study how a cell self-organizes in space and time. Here, we discuss recent advances in understanding how the cell acquires and maintains its regular rod shape and uses it to control cell division. The cellular body plan is established by microtubules, which mark antipodal growth zones and medial division. In turn, cellular dimensions are defined by the small GTPase Cdc42 and downstream regulators of vesicle trafficking. Yeast cells then repetitively use their simple rod shape to orchestrate the position and timing of cell division.
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Affiliation(s)
- Olivier Hachet
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Biophore Building, CH-1015 Lausanne, Switzerland
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36
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Abstract
Cdc42 is a key factor in the control of cell polarity and morphogenesis. Fission yeast Cdc42 regulates formin activation and actin cable assembly. Cdc42 is also required for exocyst function, contributing to polarized secretion. Additionally, Cdc42 participates in membrane trafficking, endosome recycling, and vacuole formation. We show here how Cdc42 is required for the correct transport/recycling to the plasma membrane of the glucan synthases Bgs1 and Bgs4, responsible of cell wall biosynthesis and polarized growth at the cell tips.
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Affiliation(s)
- Miguel Estravis
- CSIC; Departamento de Microbiología y Genética; Instituto de Biología Funcional y Genómica; Universidad de Salamanca; Edificio Departamental; Salamanca, Spain
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37
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Jourdain I, Dooley HC, Toda T. Fission yeast sec3 bridges the exocyst complex to the actin cytoskeleton. Traffic 2012; 13:1481-95. [PMID: 22891673 PMCID: PMC3531892 DOI: 10.1111/j.1600-0854.2012.01408.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Revised: 08/10/2012] [Accepted: 08/14/2012] [Indexed: 12/29/2022]
Abstract
The exocyst complex tethers post-Golgi secretory vesicles to the plasma membrane prior to docking and fusion. In this study, we identify Sec3, the missing component of the Schizosaccharomyces pombe exocyst complex (SpSec3). SpSec3 shares many properties with its orthologs, and its mutants are rescued by human Sec3/EXOC1. Although involved in exocytosis, SpSec3 does not appear to mark the site of exocyst complex assembly at the plasma membrane. It does, however, mark the sites of actin cytoskeleton recruitment and controls the organization of all three yeast actin structures: the actin cables, endocytic actin patches and actomyosin ring. Specifically, SpSec3 physically interacts with For3 and sec3 mutants have no actin cables as a result of a failure to polarize this nucleating formin. SpSec3 also interacts with actin patch components and sec3 mutants have depolarized actin patches of reduced endocytic capacity. Finally, the constriction and disassembly of the cytokinetic actomyosin ring is compromised in these sec3 mutant cells. We propose that a role of SpSec3 is to spatially couple actin machineries and their independently polarized regulators. As a consequence of its dual role in secretion and actin organization, Sec3 appears as a major co-ordinator of cell morphology in fission yeast.
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Affiliation(s)
- Isabelle Jourdain
- Cell Regulation Laboratory, London Research Institute, Cancer Research UK, 44 Lincoln's Inn Fields, London, WC2A 3LY, UK.
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38
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Bendezú FO, Vincenzetti V, Martin SG. Fission yeast Sec3 and Exo70 are transported on actin cables and localize the exocyst complex to cell poles. PLoS One 2012; 7:e40248. [PMID: 22768263 PMCID: PMC3386988 DOI: 10.1371/journal.pone.0040248] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Accepted: 06/03/2012] [Indexed: 02/02/2023] Open
Abstract
The exocyst complex is essential for many exocytic events, by tethering vesicles at the plasma membrane for fusion. In fission yeast, polarized exocytosis for growth relies on the combined action of the exocyst at cell poles and myosin-driven transport along actin cables. We report here the identification of fission yeast Schizosaccharomyces pombe Sec3 protein, which we identified through sequence homology of its PH-like domain. Like other exocyst subunits, sec3 is required for secretion and cell division. Cells deleted for sec3 are only conditionally lethal and can proliferate when osmotically stabilized. Sec3 is redundant with Exo70 for viability and for the localization of other exocyst subunits, suggesting these components act as exocyst tethers at the plasma membrane. Consistently, Sec3 localizes to zones of growth independently of other exocyst subunits but depends on PIP2 and functional Cdc42. FRAP analysis shows that Sec3, like all other exocyst subunits, localizes to cell poles largely independently of the actin cytoskeleton. However, we show that Sec3, Exo70 and Sec5 are transported by the myosin V Myo52 along actin cables. These data suggest that the exocyst holocomplex, including Sec3 and Exo70, is present on exocytic vesicles, which can reach cell poles by either myosin-driven transport or random walk.
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Affiliation(s)
- Felipe O. Bendezú
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Vincent Vincenzetti
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Sophie G. Martin
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
- * E-mail:
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39
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Bernal M, Sanchez-Romero MA, Salas-Pino S, Daga RR. Regulation of fission yeast morphogenesis by PP2A activator pta2. PLoS One 2012; 7:e32823. [PMID: 22403715 PMCID: PMC3293916 DOI: 10.1371/journal.pone.0032823] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2012] [Accepted: 02/06/2012] [Indexed: 12/17/2022] Open
Abstract
Cell polarization is key for the function of most eukaryotic cells, and regulates cell shape, migration and tissue architecture. Fission yeast, Schizosaccharomyces pombe cells are cylindrical and polarize cell growth to one or both cell tips dependent on the cell cycle stage. Whereas microtubule cytoskeleton contributes to the positioning of the growth sites by delivering polarity factors to the cell ends, the Cdc42 GTPase polarizes secretion via actin-dependent delivery and tethering of secretory vesicles to plasma membrane. How growth is restricted to cell tips and how re-initiation of tip growth is regulated in the cell cycle remains poorly understood. In this work we investigated the function of protein phosphatase type 2A (PP2A) in S. pombe morphogenesis by deleting the evolutionary conserved PTPA-type regulatory subunit that we named pta2. pta2-deleted cells showed morphological defects and altered growth pattern. Consistent with this, actin patches and active Cdc42 were mislocalized in the pta2 deletion. These defects were additive to the lack of Cdc42-GAP Rga4. pta2Δ cells show upregulated Cdc42 activity and pta2 interacts genetically with polarisome components Tea1, Tea4 and For3 leading to complete loss of cell polarity and rounded morphology. Thus, regulation of polarity by PP2A requires the polarisome and involves Pta2-dependent control of Cdc42 activity.
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Affiliation(s)
| | | | | | - Rafael R. Daga
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide-Consejo Superior de Investigaciones Científicas, Junta de Andalucia, Sevilla, Spain
- * E-mail:
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