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Varela Salgado M, Adriaans IE, Touati SA, Ibanes S, Lai-Kee-Him J, Ancelin A, Cipelletti L, Picas L, Piatti S. Phosphorylation of the F-BAR protein Hof1 drives septin ring splitting in budding yeast. Nat Commun 2024; 15:3383. [PMID: 38649354 PMCID: PMC11035697 DOI: 10.1038/s41467-024-47709-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Accepted: 04/09/2024] [Indexed: 04/25/2024] Open
Abstract
A double septin ring accompanies cytokinesis in yeasts and mammalian cells. In budding yeast, reorganisation of the septin collar at the bud neck into a dynamic double ring is essential for actomyosin ring constriction and cytokinesis. Septin reorganisation requires the Mitotic Exit Network (MEN), a kinase cascade essential for cytokinesis. However, the effectors of MEN in this process are unknown. Here we identify the F-BAR protein Hof1 as a critical target of MEN in septin remodelling. Phospho-mimicking HOF1 mutant alleles overcome the inability of MEN mutants to undergo septin reorganisation by decreasing Hof1 binding to septins and facilitating its translocation to the actomyosin ring. Hof1-mediated septin rearrangement requires its F-BAR domain, suggesting that it may involve a local membrane remodelling that leads to septin reorganisation. In vitro Hof1 can induce the formation of intertwined septin bundles, while a phosphomimetic Hof1 protein has impaired septin-bundling activity. Altogether, our data indicate that Hof1 modulates septin architecture in distinct ways depending on its phosphorylation status.
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Affiliation(s)
- Maritzaida Varela Salgado
- CRBM (Centre de Recherche en Biologie cellulaire de Montpellier), University of Montpellier, CNRS UMR 5237, 34293, Montpellier, France
| | - Ingrid E Adriaans
- CRBM (Centre de Recherche en Biologie cellulaire de Montpellier), University of Montpellier, CNRS UMR 5237, 34293, Montpellier, France
| | - Sandra A Touati
- Université Paris Cité, CNRS, Institut Jacques Monod, 75013, Paris, France
| | - Sandy Ibanes
- CRBM (Centre de Recherche en Biologie cellulaire de Montpellier), University of Montpellier, CNRS UMR 5237, 34293, Montpellier, France
| | - Joséphine Lai-Kee-Him
- CBS (Centre de Biologie Structurale), University of Montpellier, CNRS UMR 5048, INSERM U 1054, 34090, Montpellier, France
| | - Aurélie Ancelin
- CBS (Centre de Biologie Structurale), University of Montpellier, CNRS UMR 5048, INSERM U 1054, 34090, Montpellier, France
| | - Luca Cipelletti
- L2C (Laboratoire Charles Coulomb), University of Montpellier, CNRS 34095, Montpellier, France
- IUF (Institut Universitaire de France, 75231, Paris, France
| | - Laura Picas
- IRIM (Institut de Recherche en Infectiologie de Montpellier), University of Montpellier, CNRS UMR 9004, 34293, Montpellier, France
| | - Simonetta Piatti
- CRBM (Centre de Recherche en Biologie cellulaire de Montpellier), University of Montpellier, CNRS UMR 5237, 34293, Montpellier, France.
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2
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Wang K, Okada H, Wloka C, Bi E. Unraveling the mechanisms and evolution of a two-domain module in IQGAP proteins for controlling eukaryotic cytokinesis. Cell Rep 2023; 42:113510. [PMID: 38041816 PMCID: PMC10809011 DOI: 10.1016/j.celrep.2023.113510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 08/17/2023] [Accepted: 11/13/2023] [Indexed: 12/04/2023] Open
Abstract
The IQGAP family of proteins plays a crucial role in cytokinesis across diverse organisms, but the underlying mechanisms are not fully understood. In this study, we demonstrate that IQGAPs in budding yeast, fission yeast, and human cells use a two-domain module to regulate their localization as well as the assembly and disassembly of the actomyosin ring during cytokinesis. Strikingly, the calponin homology domains (CHDs) in these IQGAPs bind to distinct cellular F-actin structures with varying specificity, whereas the non-conserved domains immediately downstream of the CHDs in these IQGAPs all target the division site, but differ in timing, localization strength, and binding partners. We also demonstrate that human IQGAP3 acts in parallel to septins and myosin-IIs to mediate the role of anillin in cytokinesis. Collectively, our findings highlight the two-domain mechanism by which IQGAPs regulate cytokinesis in distantly related organisms as well as their evolutionary conservation and divergence.
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Affiliation(s)
- Kangji Wang
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6058, USA
| | - Hiroki Okada
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6058, USA
| | - Carsten Wloka
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6058, USA; Experimental Ophthalmology, Department of Ophthalmology, Charité - Universitätsmedizin Berlin, A Corporate Member of Freie Universität, Humboldt-University, The Berlin Institute of Health, Berlin, Germany
| | - Erfei Bi
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6058, USA.
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3
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Okada H, Chen X, Wang K, Marquardt J, Bi E. Bni5 tethers myosin-II to septins to enhance retrograde actin flow and the robustness of cytokinesis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.07.566094. [PMID: 37986946 PMCID: PMC10659389 DOI: 10.1101/2023.11.07.566094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
The collaboration between septins and myosin-II in driving processes outside of cytokinesis remains largely uncharted. Here, we demonstrate that Bni5 in the budding yeast S. cerevisiae interacts with myosin-II, septin filaments, and the septin-associated kinase Elm1 via distinct domains at its N- and C-termini, thereby tethering the mobile myosin-II to the stable septin hourglass at the division site from bud emergence to the onset of cytokinesis. The septin and Elm1-binding domains, together with a central disordered region, of Bni5 control timely remodeling of the septin hourglass into a double ring, enabling the actomyosin ring constriction. The Bni5-tethered myosin-II enhances retrograde actin cable flow, which contributes to the asymmetric inheritance of mitochondria-associated protein aggregates during cell division, and also strengthens cytokinesis against various perturbations. Thus, we have established a biochemical pathway involving septin-Bni5-myosin-II interactions at the division site, which can inform mechanistic understanding of the role of myosin-II in other retrograde flow systems. Summary Okada et al. have determined the molecular mechanism underlying the Bni5 interactions with septins and myosin-II at the cell division site and uncovered its roles in promoting retrograde actin flow and the robustness of cytokinesis in budding yeast.
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Rossi AM, Bohnert KA, Gould KL. The fission yeast cytokinetic ring component Fic1 promotes septum formation. Biol Open 2023; 12:308901. [PMID: 37158439 PMCID: PMC10184318 DOI: 10.1242/bio.059957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Accepted: 04/19/2023] [Indexed: 05/10/2023] Open
Abstract
In Schizosaccharomyces pombe, septum formation is coordinated with cytokinetic ring constriction but the mechanisms linking these events are unclear. In this study, we explored the role of the cytokinetic ring component Fic1, first identified by its interaction with the F-BAR protein Cdc15, in septum formation. We found that the fic1 phospho-ablating mutant, fic1-2A, is a gain-of-function allele that suppresses myo2-E1, the temperature-sensitive allele of the essential type-II myosin, myo2. This suppression is achieved by the promotion of septum formation and required Fic1's interaction with the F-BAR proteins Cdc15 and Imp2. Additionally, we found that Fic1 interacts with Cyk3 and that this interaction was likewise required for Fic1's role in septum formation. Fic1, Cdc15, Imp2, and Cyk3 are the orthologs of the Saccharomyces cerevisiae ingression progression complex, which stimulates the chitin synthase Chs2 to promote primary septum formation. However, our findings indicate that Fic1 promotes septum formation and cell abscission independently of the S. pombe Chs2 ortholog. Thus, while similar complexes exist in the two yeasts that each promote septation, they appear to have different downstream effectors.
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Affiliation(s)
- Anthony M Rossi
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240, USA
| | - K Adam Bohnert
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240, USA
| | - Kathleen L Gould
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240, USA
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5
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Rossi AM, Bohnert KA, Gould KL. The fission yeast cytokinetic ring component Fic1 promotes septum formation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.13.532462. [PMID: 36993237 PMCID: PMC10054984 DOI: 10.1101/2023.03.13.532462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
In Schizosaccharomyces pombe septum formation is coordinated with cytokinetic ring constriction but the mechanisms linking these events are unclear. In this study, we explored the role of the cytokinetic ring component Fic1, first identified by its interaction with the F-BAR protein Cdc15, in septum formation. We found that the fic1 phospho-ablating mutant, fic1-2A , is a gain-of-function allele that suppresses myo2-E1 , the temperature-sensitive allele of the essential type-II myosin, myo2 . This suppression is achieved by the promotion of septum formation and required Fic1's interaction with the F-BAR proteins Cdc15 and Imp2. Additionally, we found that Fic1 interacts with Cyk3 and that this interaction was likewise required for Fic1's role in septum formation. Fic1, Cdc15, Imp2, and Cyk3 are the orthologs of the Saccharomyces cerevisiae ingression progression complex, which stimulates the chitin synthase Chs2 to promote primary septum formation. However, our findings indicate that Fic1 promotes septum formation and cell abscission independently of the S. pombe Chs2 ortholog. Thus, while similar complexes exist in the two yeasts that each promote septation, they appear to have different downstream effectors. Summary Statement The S. pombe cytokinetic ring protein Fic1 promotes septum formation in a manner dependent on interactions with the cytokinetic ring components Cdc15, Imp2, and Cyk3.
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Moyano-Rodríguez Y, Vaquero D, Vilalta-Castany O, Foltman M, Sanchez-Diaz A, Queralt E. PP2A-Cdc55 phosphatase regulates actomyosin ring contraction and septum formation during cytokinesis. Cell Mol Life Sci 2022; 79:165. [PMID: 35230542 PMCID: PMC8888506 DOI: 10.1007/s00018-022-04209-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 02/11/2022] [Accepted: 02/13/2022] [Indexed: 11/03/2022]
Abstract
Eukaryotic cells divide and separate all their components after chromosome segregation by a process called cytokinesis to complete cell division. Cytokinesis is highly regulated by the recruitment of the components to the division site and through post-translational modifications such as phosphorylations. The budding yeast mitotic kinases Cdc28-Clb2, Cdc5, and Dbf2-Mob1 phosphorylate several cytokinetic proteins contributing to the regulation of cytokinesis. The PP2A-Cdc55 phosphatase regulates mitosis counteracting Cdk1- and Cdc5-dependent phosphorylation. This prompted us to propose that PP2A-Cdc55 could also be counteracting the mitotic kinases during cytokinesis. Here we show that in the absence of Cdc55, AMR contraction and the primary septum formation occur asymmetrically to one side of the bud neck supporting a role for PP2A-Cdc55 in cytokinesis regulation. In addition, by in vivo and in vitro assays, we show that PP2A-Cdc55 dephosphorylates the chitin synthase II (Chs2 in budding yeast) a component of the Ingression Progression Complexes (IPCs) involved in cytokinesis. Interestingly, the non-phosphorylable version of Chs2 rescues the asymmetric AMR contraction and the defective septa formation observed in cdc55∆ mutant cells. Therefore, timely dephosphorylation of the Chs2 by PP2A-Cdc55 is crucial for proper actomyosin ring contraction. These findings reveal a new mechanism of cytokinesis regulation by the PP2A-Cdc55 phosphatase and extend our knowledge of the involvement of multiple phosphatases during cytokinesis.
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Affiliation(s)
- Yolanda Moyano-Rodríguez
- Cell Cycle Group, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), Av. Gran Via de L'Hospitalet 199-203, L'Hospitalet de Llobregat, Barcelona, Spain
| | - David Vaquero
- Cell Cycle Group, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), Av. Gran Via de L'Hospitalet 199-203, L'Hospitalet de Llobregat, Barcelona, Spain.,Instituto de Biomedicina de Valencia (IBV-CSIC), C/ Jaume Roig 11, Valencia, Spain
| | - Odena Vilalta-Castany
- Cell Cycle Group, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), Av. Gran Via de L'Hospitalet 199-203, L'Hospitalet de Llobregat, Barcelona, Spain
| | - Magdalena Foltman
- Instituto de Biomedicina y Biotecnología de Cantabria, Universidad de Cantabria, CSIC, Santander, Spain.,Departamento de Biología Molecular, Facultad de Medicina, Universidad de Cantabria, Santander, Spain
| | - Alberto Sanchez-Diaz
- Instituto de Biomedicina y Biotecnología de Cantabria, Universidad de Cantabria, CSIC, Santander, Spain.,Departamento de Biología Molecular, Facultad de Medicina, Universidad de Cantabria, Santander, Spain
| | - Ethel Queralt
- Cell Cycle Group, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), Av. Gran Via de L'Hospitalet 199-203, L'Hospitalet de Llobregat, Barcelona, Spain. .,Instituto de Biomedicina de Valencia (IBV-CSIC), C/ Jaume Roig 11, Valencia, Spain.
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7
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Okada H, MacTaggart B, Ohya Y, Bi E. The kinetic landscape and interplay of protein networks in cytokinesis. iScience 2021; 24:101917. [PMID: 33392480 PMCID: PMC7773586 DOI: 10.1016/j.isci.2020.101917] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 12/03/2020] [Accepted: 12/07/2020] [Indexed: 11/08/2022] Open
Abstract
Cytokinesis is executed by protein networks organized into functional modules. Individual proteins within each module have been characterized to various degrees. However, the collective behavior and interplay of the modules remain poorly understood. In this study, we conducted quantitative time-lapse imaging to analyze the accumulation kinetics of more than 20 proteins from different modules of cytokinesis in budding yeast. This analysis has led to a comprehensive picture of the kinetic landscape of cytokinesis, from actomyosin ring (AMR) assembly to cell separation. It revealed that the AMR undergoes biphasic constriction and that the switch between the constriction phases is likely triggered by AMR maturation and primary septum formation. This analysis also provided further insights into the functions of actin filaments and the transglutaminase-like protein Cyk3 in cytokinesis and, in addition, defined Kre6 as the likely enzyme that catalyzes β-1,6-glucan synthesis to drive cell wall maturation during cell growth and division. Cytokinesis is executed by protein modules each with a unique kinetic signature Actomyosin ring constricts in a biphasic manner that is elaborately regulated The transglutaminase-like domain in Cyk3 plays a dual role in cytokinesis Kre6 catalyzes β-1,6-glucan synthesis at the cell surface during growth and division
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Affiliation(s)
- Hiroki Okada
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6058, USA
| | - Brittany MacTaggart
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6058, USA
| | - Yoshikazu Ohya
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo, Kashiwa, Chiba, 277-8562, Japan
| | - Erfei Bi
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6058, USA
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8
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Magliozzi JO, Moseley JB. Connecting cell polarity signals to the cytokinetic machinery in yeast and metazoan cells. Cell Cycle 2021; 20:1-10. [PMID: 33397181 DOI: 10.1080/15384101.2020.1864941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
Polarized growth and cytokinesis are two fundamental cellular processes that exist in virtually all cell types. Mechanisms for asymmetric distribution of materials allow for cells to grow in a polarized manner. This gives rise to a variety of cell shapes seen throughout all cell types. Following polarized growth during interphase, dividing cells assemble a cytokinetic ring containing the protein machinery to constrict and separate daughter cells. Here, we discuss how cell polarity signaling pathways act on cytokinesis, with a focus on direct regulation of the contractile actomyosin ring (CAR). Recent studies have exploited phosphoproteomics to identify new connections between cell polarity kinases and CAR proteins. Existing evidence suggests that some polarity kinases guide the local organization of CAR proteins and structures while also contributing to global organization of the division plane within a cell. We provide several examples of this regulation from budding yeast, fission yeast, and metazoan cells. In some cases, kinase-substrate connections point to conserved processes in these different organisms. We point to several examples where future work can indicate the degree of conservation and divergence in the cell division process of these different organisms.
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Affiliation(s)
- Joseph O Magliozzi
- Department of Biochemistry and Cell Biology, The Geisel School of Medicine at Dartmouth , Hanover, New Hampshire, USA
| | - James B Moseley
- Department of Biochemistry and Cell Biology, The Geisel School of Medicine at Dartmouth , Hanover, New Hampshire, USA
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9
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Wang K, Okada H, Bi E. Comparative Analysis of the Roles of Non-muscle Myosin-IIs in Cytokinesis in Budding Yeast, Fission Yeast, and Mammalian Cells. Front Cell Dev Biol 2020; 8:593400. [PMID: 33330476 PMCID: PMC7710916 DOI: 10.3389/fcell.2020.593400] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 10/30/2020] [Indexed: 12/31/2022] Open
Abstract
The contractile ring, which plays critical roles in cytokinesis in fungal and animal cells, has fascinated biologists for decades. However, the basic question of how the non-muscle myosin-II and actin filaments are assembled into a ring structure to drive cytokinesis remains poorly understood. It is even more mysterious why and how the budding yeast Saccharomyces cerevisiae, the fission yeast Schizosaccharomyces pombe, and humans construct the ring structure with one, two, and three myosin-II isoforms, respectively. Here, we provide a comparative analysis of the roles of the non-muscle myosin-IIs in cytokinesis in these three model systems, with the goal of defining the common and unique features and highlighting the major questions regarding this family of proteins.
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Affiliation(s)
- Kangji Wang
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Hiroki Okada
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Erfei Bi
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
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10
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Garabedian MV, Wirshing A, Vakhrusheva A, Turegun B, Sokolova OS, Goode BL. A septin-Hof1 scaffold at the yeast bud neck binds and organizes actin cables. Mol Biol Cell 2020; 31:1988-2001. [PMID: 32579428 PMCID: PMC7543067 DOI: 10.1091/mbc.e19-12-0693] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Cellular actin arrays are often highly organized, with characteristic patterns critical to their in vivo functions, yet the mechanisms for establishing these higher order geometries remain poorly understood. In Saccharomyces cerevisiae, formin-polymerized actin cables are spatially organized and aligned along the mother–bud axis to facilitate polarized vesicle traffic. Here, we show that the bud neck–associated F-BAR protein Hof1, independent of its functions in regulating the formin Bnr1, binds to actin filaments and organizes actin cables in vivo. Hof1 bundles actin filaments and links them to septins in vitro. F-actin binding is mediated by the “linker” domain of Hof1, and its deletion leads to cable organization defects in vivo. Using superresolution imaging, we show that Hof1 and septins are patterned at the bud neck into evenly spaced axial pillars (∼200 nm apart), from which actin cables emerge and grow into the mother cell. These results suggest that Hof1, while bound to septins at the bud neck, not only regulates Bnr1 activity, but also binds to actin cables and aligns them along the mother–bud axis. More broadly, these findings provide a strong example of how an actin regulatory protein can be spatially patterned at the cell cortex to govern actin network geometry.
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Affiliation(s)
- Mikael V Garabedian
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, MA, 02454
| | - Alison Wirshing
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, MA, 02454
| | - Anna Vakhrusheva
- Department of Bioengineering, Faculty of Biology, Lomonosov Moscow State University, Moscow 119234, Russia
| | - Bengi Turegun
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, MA, 02454
| | - Olga S Sokolova
- Department of Bioengineering, Faculty of Biology, Lomonosov Moscow State University, Moscow 119234, Russia
| | - Bruce L Goode
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, MA, 02454
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11
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Yeast as a Model to Understand Actin-Mediated Cellular Functions in Mammals-Illustrated with Four Actin Cytoskeleton Proteins. Cells 2020; 9:cells9030672. [PMID: 32164332 PMCID: PMC7140605 DOI: 10.3390/cells9030672] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 03/05/2020] [Accepted: 03/05/2020] [Indexed: 12/31/2022] Open
Abstract
The budding yeast Saccharomyces cerevisiae has an actin cytoskeleton that comprises a set of protein components analogous to those found in the actin cytoskeletons of higher eukaryotes. Furthermore, the actin cytoskeletons of S. cerevisiae and of higher eukaryotes have some similar physiological roles. The genetic tractability of budding yeast and the availability of a stable haploid cell type facilitates the application of molecular genetic approaches to assign functions to the various actin cytoskeleton components. This has provided information that is in general complementary to that provided by studies of the equivalent proteins of higher eukaryotes and hence has enabled a more complete view of the role of these proteins. Several human functional homologues of yeast actin effectors are implicated in diseases. A better understanding of the molecular mechanisms underpinning the functions of these proteins is critical to develop improved therapeutic strategies. In this article we chose as examples four evolutionarily conserved proteins that associate with the actin cytoskeleton: (1) yeast Hof1p/mammalian PSTPIP1, (2) yeast Rvs167p/mammalian BIN1, (3) yeast eEF1A/eEF1A1 and eEF1A2 and (4) yeast Yih1p/mammalian IMPACT. We compare the knowledge on the functions of these actin cytoskeleton-associated proteins that has arisen from studies of their homologues in yeast with information that has been obtained from in vivo studies using live animals or in vitro studies using cultured animal cell lines.
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12
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Bhattacharjee R, Mangione MC, Wos M, Chen JS, Snider CE, Roberts-Galbraith RH, McDonald NA, Presti LL, Martin SG, Gould KL. DYRK kinase Pom1 drives F-BAR protein Cdc15 from the membrane to promote medial division. Mol Biol Cell 2020; 31:917-929. [PMID: 32101481 PMCID: PMC7185970 DOI: 10.1091/mbc.e20-01-0026] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
In many organisms, positive and negative signals cooperate to position the division site for cytokinesis. In the rod-shaped fission yeast Schizosaccharomyces pombe, symmetric division is achieved through anillin/Mid1-dependent positive cues released from the central nucleus and negative signals from the DYRK-family polarity kinase Pom1 at cell tips. Here we establish that Pom1's kinase activity prevents septation at cell tips even if Mid1 is absent or mislocalized. We also find that Pom1 phosphorylation of F-BAR protein Cdc15, a major scaffold of the division apparatus, disrupts Cdc15's ability to bind membranes and paxillin, Pxl1, thereby inhibiting Cdc15's function in cytokinesis. A Cdc15 mutant carrying phosphomimetic versions of Pom1 sites or deletion of Cdc15 binding partners suppresses division at cell tips in cells lacking both Mid1 and Pom1 signals. Thus, inhibition of Cdc15-scaffolded septum formation at cell poles is a key Pom1 mechanism that ensures medial division.
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Affiliation(s)
- Rahul Bhattacharjee
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37205
| | - MariaSanta C Mangione
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37205
| | - Marcin Wos
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37205
| | - Jun-Song Chen
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37205
| | - Chloe E Snider
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37205
| | - Rachel H Roberts-Galbraith
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37205
| | - Nathan A McDonald
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37205
| | - Libera Lo Presti
- Department of Fundamental Microbiology, University of Lausanne, 1015 Lausanne, Switzerland
| | - Sophie G Martin
- Department of Fundamental Microbiology, University of Lausanne, 1015 Lausanne, Switzerland
| | - Kathleen L Gould
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37205
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13
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Brace JL, Doerfler MD, Weiss EL. A cell separation checkpoint that enforces the proper order of late cytokinetic events. J Cell Biol 2019; 218:150-170. [PMID: 30455324 PMCID: PMC6314563 DOI: 10.1083/jcb.201805100] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 08/28/2018] [Accepted: 10/05/2018] [Indexed: 01/28/2023] Open
Abstract
Eukaryotic cell division requires dependency relationships in which late processes commence only after early ones are appropriately completed. We have discovered a system that blocks late events of cytokinesis until early ones are successfully accomplished. In budding yeast, cytokinetic actomyosin ring contraction and membrane ingression are coupled with deposition of an extracellular septum that is selectively degraded in its primary septum immediately after its completion by secreted enzymes. We find this secretion event is linked to septum completion and forestalled when the process is slowed. Delay of septum degradation requires Fir1, an intrinsically disordered protein localized to the cytokinesis site that is degraded upon septum completion but stabilized when septation is aberrant. Fir1 protects cytokinesis in part by inhibiting a separation-specific exocytosis function of the NDR/LATS kinase Cbk1, a key component of "hippo" signaling that induces mother-daughter separation. We term this system enforcement of cytokinesis order, a checkpoint ensuring proper temporal sequence of mechanistically incompatible processes of cytokinesis.
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Affiliation(s)
- Jennifer L Brace
- Department of Molecular Biosciences, Northwestern University, Evanston, IL
| | - Matthew D Doerfler
- Department of Molecular Biosciences, Northwestern University, Evanston, IL
| | - Eric L Weiss
- Department of Molecular Biosciences, Northwestern University, Evanston, IL
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14
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Garabedian MV, Stanishneva-Konovalova T, Lou C, Rands TJ, Pollard LW, Sokolova OS, Goode BL. Integrated control of formin-mediated actin assembly by a stationary inhibitor and a mobile activator. J Cell Biol 2018; 217:3512-3530. [PMID: 30076201 PMCID: PMC6168263 DOI: 10.1083/jcb.201803164] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 06/20/2018] [Accepted: 07/17/2018] [Indexed: 12/15/2022] Open
Abstract
This study shows that in vivo actin nucleation by the yeast formin Bnr1 is controlled through the coordinated effects of two distinct regulators, a stationary inhibitor (the F-BAR protein Hof1) and a mobile activator (Bud6), establishing a positive feedback loop for precise spatial and temporal control of actin assembly. Formins are essential actin assembly factors whose activities are controlled by a diverse array of binding partners. Until now, most formin ligands have been studied on an individual basis, leaving open the question of how multiple inputs are integrated to regulate formins in vivo. Here, we show that the F-BAR domain of Saccharomyces cerevisiae Hof1 interacts with the FH2 domain of the formin Bnr1 and blocks actin nucleation. Electron microscopy of the Hof1–Bnr1 complex reveals a novel dumbbell-shaped structure, with the tips of the F-BAR holding two FH2 dimers apart. Deletion of Hof1’s F-BAR domain in vivo results in disorganized actin cables and secretory defects. The formin-binding protein Bud6 strongly alleviates Hof1 inhibition in vitro, and bud6Δ suppresses hof1Δ defects in vivo. Whereas Hof1 stably resides at the bud neck, we show that Bud6 is delivered to the neck on secretory vesicles. We propose that Hof1 and Bud6 functions are intertwined as a stationary inhibitor and a mobile activator, respectively.
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Affiliation(s)
- Mikael V Garabedian
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, MA
| | | | - Chenyu Lou
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, MA
| | - Thomas J Rands
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, MA
| | - Luther W Pollard
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, MA
| | - Olga S Sokolova
- Bioengineering Department, Faculty of Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Bruce L Goode
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, MA
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15
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Chakraborty S, Ain R. NOSTRIN: A novel modulator of trophoblast giant cell differentiation. Stem Cell Res 2018; 31:135-146. [PMID: 30086473 DOI: 10.1016/j.scr.2018.07.023] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Revised: 07/21/2018] [Accepted: 07/27/2018] [Indexed: 12/13/2022] Open
Abstract
Differentiation-dependent expression of NOSTRIN in murine trophoblast cells prompted investigation on NOSTRIN's function in trophoblast differentiation. We show here that NOSTRIN levels increased in both mouse and rat placenta during gestation. NOSTRIN expression was not co-related to expression of eNOS precluding its eNOS mediated function. NOSTRIN transcripts were identified in trophoblast cells of the placenta, predominantly in trophoblast giant cells (TGC). Precocious over-expression of NOSTRIN during differentiation of trophoblast stem cells led to up-regulation of genetic markers associated with invasion (Prl4a1, Prl2a1) and TGC formation (Prl2c2, Prl3d1, Prl3b1). The functional consequence of NOSTRIN over-expression was increased TGC formation and trophoblast cell invasion. Furthermore, number of polyploid TGCs that arise by endoreduplication, were higher in presence of NOSTRIN. Early induction of NOSTRIN was associated with substantial decrease in G/F actin ratio and augmentation of N-WASP-Dynamin-NOSTRIN ternary complex formation that might be partially responsible for nucleation of actin filaments. NOSTRIN also formed a complex with Cdk1 and increased phosphorylation of T14 and Y15 residues that inhibits cytokinesis. Interestingly, SH3 domain deleted NOSTRIN was ineffective in eliciting NOSTRIN's function in differentiating trophoblast cells. These findings demonstrate that NOSTRIN potentiates trophoblast differentiation towards TGC trajectory that is critical for hemochorial placentation.
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Affiliation(s)
- Shreeta Chakraborty
- Division of Cell Biology and Physiology, CSIR-Indian Institute of Chemical Biology, Kolkata 700032, West Bengal, India
| | - Rupasri Ain
- Division of Cell Biology and Physiology, CSIR-Indian Institute of Chemical Biology, Kolkata 700032, West Bengal, India.
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16
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Foltman M, Filali-Mouncef Y, Crespo D, Sanchez-Diaz A. Cell polarity protein Spa2 coordinates Chs2 incorporation at the division site in budding yeast. PLoS Genet 2018; 14:e1007299. [PMID: 29601579 PMCID: PMC5895073 DOI: 10.1371/journal.pgen.1007299] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 04/11/2018] [Accepted: 03/07/2018] [Indexed: 01/06/2023] Open
Abstract
Deposition of additional plasma membrane and cargoes during cytokinesis in eukaryotic cells must be coordinated with actomyosin ring contraction, plasma membrane ingression and extracellular matrix remodelling. The process by which the secretory pathway promotes specific incorporation of key factors into the cytokinetic machinery is poorly understood. Here, we show that cell polarity protein Spa2 interacts with actomyosin ring components during cytokinesis. Spa2 directly binds to cytokinetic factors Cyk3 and Hof1. The lethal effects of deleting the SPA2 gene in the absence of either Cyk3 or Hof1 can be suppressed by expression of the hypermorphic allele of the essential chitin synthase II (Chs2), a transmembrane protein transported on secretory vesicles that makes the primary septum during cytokinesis. Spa2 also interacts directly with the chitin synthase Chs2. Interestingly, artificial incorporation of Chs2 into the cytokinetic machinery allows the localisation of Spa2 at the site of division. In addition, increased Spa2 protein levels promote Chs2 incorporation at the site of division and primary septum formation. Our data indicate that Spa2 is recruited to the cleavage site to co-operate with the secretory vesicle system and particular actomyosin ring components to promote the incorporation of Chs2 into the so-called 'ingression progression complexes' during cytokinesis in budding yeast.
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Affiliation(s)
- Magdalena Foltman
- Instituto de Biomedicina y Biotecnología de Cantabria, Universidad de Cantabria, CSIC, Santander, Spain
- Departamento de Biología Molecular, Facultad de Medicina, Universidad de Cantabria, Santander, Spain
| | - Yasmina Filali-Mouncef
- Instituto de Biomedicina y Biotecnología de Cantabria, Universidad de Cantabria, CSIC, Santander, Spain
- Departamento de Biología Molecular, Facultad de Medicina, Universidad de Cantabria, Santander, Spain
| | - Damaso Crespo
- Departamento de Anatomía y Biología Celular, Facultad de Medicina, Universidad de Cantabria, Santander, Spain
| | - Alberto Sanchez-Diaz
- Instituto de Biomedicina y Biotecnología de Cantabria, Universidad de Cantabria, CSIC, Santander, Spain
- Departamento de Biología Molecular, Facultad de Medicina, Universidad de Cantabria, Santander, Spain
- * E-mail:
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17
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Wang M, Nishihama R, Onishi M, Pringle JR. Role of the Hof1-Cyk3 interaction in cleavage-furrow ingression and primary-septum formation during yeast cytokinesis. Mol Biol Cell 2018; 29:597-609. [PMID: 29321253 PMCID: PMC6004579 DOI: 10.1091/mbc.e17-04-0227] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 12/26/2017] [Accepted: 01/03/2018] [Indexed: 11/11/2022] Open
Abstract
In Saccharomyces cerevisiae, it is well established that Hof1, Cyk3, and Inn1 contribute to septum formation and cytokinesis. Because hof1∆ and cyk3∆ single mutants have relatively mild defects but hof1∆ cyk3∆ double mutants are nearly dead, it has been hypothesized that these proteins contribute to parallel pathways. However, there is also evidence that they interact physically. In this study, we examined this interaction and its functional significance in detail. Our data indicate that the interaction 1) is mediated by a direct binding of the Hof1 SH3 domain to a proline-rich motif in Cyk3; 2) occurs specifically at the time of cytokinesis but is independent of the (hyper)phosphorylation of both proteins that occurs at about the same time; 3) is dispensable for the normal localization of both proteins; 4) is essential for normal primary-septum formation and a normal rate of cleavage-furrow ingression; and 5) becomes critical for growth when either Inn1 or the type II myosin Myo1 (a key component of the contractile actomyosin ring) is absent. The similarity in phenotype between cyk3∆ mutants and mutants specifically lacking the Hof1-Cyk3 interaction suggests that the interaction is particularly important for Cyk3 function, but it may be important for Hof1 function as well.
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Affiliation(s)
- Meng Wang
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305
| | - Ryuichi Nishihama
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305
| | - Masayuki Onishi
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305
| | - John R Pringle
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305
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18
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Altamirano S, Chandrasekaran S, Kozubowski L. Mechanisms of Cytokinesis in Basidiomycetous Yeasts. FUNGAL BIOL REV 2017; 31:73-87. [PMID: 28943887 DOI: 10.1016/j.fbr.2016.12.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
While mechanisms of cytokinesis exhibit considerable plasticity, it is difficult to precisely define the level of conservation of this essential part of cell division in fungi, as majority of our knowledge is based on ascomycetous yeasts. However, in the last decade more details have been uncovered regarding cytokinesis in the second largest fungal phylum, basidiomycetes, specifically in two yeasts, Cryptococcus neoformans and Ustilago maydis. Based on these findings, and current sequenced genomes, we summarize cytokinesis in basidiomycetous yeasts, indicating features that may be unique to this phylum, species-specific characteristics, as well as mechanisms that may be common to all eukaryotes.
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Affiliation(s)
- Sophie Altamirano
- Department of Genetics and Biochemistry, Clemson University, Clemson, South Carolina, USA
| | | | - Lukasz Kozubowski
- Department of Genetics and Biochemistry, Clemson University, Clemson, South Carolina, USA
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19
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Abstract
In budding yeast cells, cytokinesis is achieved by the successful division of the cytoplasm into two daughter cells, but the precise mechanisms of cell division and its regulation are still rather poorly understood. The Mitotic Exit Network (MEN) is the signaling cascade that is responsible for the release of Cdc14 phosphatase leading to the inactivation of the kinase activity associated to cyclin-dependent kinases (CDK), which drives exit from mitosis and a rapid and efficient cytokinesis. Mitotic CDK impairs the activation of MEN before anaphase, and activation of MEN in anaphase leads to the inactivation of CDK, which presents a challenge to determine the contribution that each pathway makes to the successful onset of cytokinesis. To determine CDK and MEN contribution to cytokinesis irrespectively of each other, here we present methods to induce cytokinesis after the inactivation of CDK activity in temperature sensitive mutants of the MEN pathway. An array of methods to monitor the cellular events associated with the successful cytokinesis is included.
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Affiliation(s)
- Magdalena Foltman
- Instituto de Biomedicina y Biotecnología de Cantabria, Consejo Superior de Investigaciones Científicas, Universidad de Cantabria, c/ Albert Einstein 22, Santander, 39011, Spain
- Departamento de Biología Molecular, Facultad de Medicina, Universidad de Cantabria, Cardenal Herrera Oria s/n, Santander, 39011, Spain
| | - Alberto Sanchez-Diaz
- Instituto de Biomedicina y Biotecnología de Cantabria, Consejo Superior de Investigaciones Científicas, Universidad de Cantabria, c/ Albert Einstein 22, Santander, 39011, Spain.
- Departamento de Biología Molecular, Facultad de Medicina, Universidad de Cantabria, Cardenal Herrera Oria s/n, Santander, 39011, Spain.
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20
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Abstract
The Mitotic Exit Network (MEN) is an essential signaling pathway, closely related to the Hippo pathway in mammals, which promotes mitotic exit and initiates cytokinesis in the budding yeast Saccharomyces cerevisiae. Here, we summarize the current knowledge about the MEN components and their regulation.
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Affiliation(s)
- Bàrbara Baro
- Department of Pediatrics, Division of Infectious Diseases,Stanford University School of Medicine, Stanford, CA, USA.
| | - Ethel Queralt
- Cancer Epigenetics & Biology Program, Hospitalet de Llobregat, Barcelona, Spain.
| | - Fernando Monje-Casas
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Consejo Superior de Investigaciones Científicas (CSIC), Avda. Américo Vespucio, s/n. P.C.T. Cartuja 93., 41092, Sevilla, Spain.
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21
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Abstract
Cytokinesis is essential for the survival of all organisms. It requires concerted functions of cell signaling, force production, exocytosis, and extracellular matrix remodeling. Due to the conservation in core components and mechanisms between fungal and animal cells, the budding yeast Saccharomyces cerevisiae has served as an attractive model for studying this fundamental process. In this review, we discuss the mechanics and regulation of distinct events of cytokinesis in budding yeast, including the assembly, constriction, and disassembly of the actomyosin ring, septum formation, abscission, and their spatiotemporal coordination. We also highlight the key concepts and questions that are common to animal and fungal cytokinesis.
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Affiliation(s)
- Yogini P Bhavsar-Jog
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Erfei Bi
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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22
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Perez AM, Finnigan GC, Roelants FM, Thorner J. Septin-Associated Protein Kinases in the Yeast Saccharomyces cerevisiae. Front Cell Dev Biol 2016; 4:119. [PMID: 27847804 PMCID: PMC5088441 DOI: 10.3389/fcell.2016.00119] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2016] [Accepted: 10/14/2016] [Indexed: 01/19/2023] Open
Abstract
Septins are a family of eukaryotic GTP-binding proteins that associate into linear rods, which, in turn, polymerize end-on-end into filaments, and further assemble into other, more elaborate super-structures at discrete subcellular locations. Hence, septin-based ensembles are considered elements of the cytoskeleton. One function of these structures that has been well-documented in studies conducted in budding yeast Saccharomyces cerevisiae is to serve as a scaffold that recruits regulatory proteins, which dictate the spatial and temporal control of certain aspects of the cell division cycle. In particular, septin-associated protein kinases couple cell cycle progression with cellular morphogenesis. Thus, septin-containing structures serve as signaling platforms that integrate a multitude of signals and coordinate key downstream networks required for cell cycle passage. This review summarizes what we currently understand about how the action of septin-associated protein kinases and their substrates control information flow to drive the cell cycle into and out of mitosis, to regulate bud growth, and especially to direct timely and efficient execution of cytokinesis and cell abscission. Thus, septin structures represent a regulatory node at the intersection of many signaling pathways. In addition, and importantly, the activities of certain septin-associated protein kinases also regulate the state of organization of the septins themselves, creating a complex feedback loop.
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Affiliation(s)
- Adam M Perez
- Division of Biochemistry, Biophysics and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley Berkeley, CA, USA
| | - Gregory C Finnigan
- Division of Biochemistry, Biophysics and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley Berkeley, CA, USA
| | - Françoise M Roelants
- Division of Biochemistry, Biophysics and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley Berkeley, CA, USA
| | - Jeremy Thorner
- Division of Biochemistry, Biophysics and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley Berkeley, CA, USA
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23
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Juanes MA, Piatti S. The final cut: cell polarity meets cytokinesis at the bud neck in S. cerevisiae. Cell Mol Life Sci 2016; 73:3115-36. [PMID: 27085703 PMCID: PMC4951512 DOI: 10.1007/s00018-016-2220-3] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Revised: 03/22/2016] [Accepted: 04/05/2016] [Indexed: 02/07/2023]
Abstract
Cell division is a fundamental but complex process that gives rise to two daughter cells. It includes an ordered set of events, altogether called "the cell cycle", that culminate with cytokinesis, the final stage of mitosis leading to the physical separation of the two daughter cells. Symmetric cell division equally partitions cellular components between the two daughter cells, which are therefore identical to one another and often share the same fate. In many cases, however, cell division is asymmetrical and generates two daughter cells that differ in specific protein inheritance, cell size, or developmental potential. The budding yeast Saccharomyces cerevisiae has proven to be an excellent system to investigate the molecular mechanisms governing asymmetric cell division and cytokinesis. Budding yeast is highly polarized during the cell cycle and divides asymmetrically, producing two cells with distinct sizes and fates. Many components of the machinery establishing cell polarization during budding are relocalized to the division site (i.e., the bud neck) for cytokinesis. In this review we recapitulate how budding yeast cells undergo polarized processes at the bud neck for cell division.
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Affiliation(s)
- Maria Angeles Juanes
- Centre de Recherche en Biologie Cellulaire de Montpellier, 1919 Route de Mende, 34293, Montpellier, France
- Brandeis University, 415 South Street, Waltham, MA, 02454, USA
| | - Simonetta Piatti
- Centre de Recherche en Biologie Cellulaire de Montpellier, 1919 Route de Mende, 34293, Montpellier, France.
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24
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Chin CF, Tan K, Onishi M, Chew Y, Augustine B, Lee WR, Yeong FM. Timely Endocytosis of Cytokinetic Enzymes Prevents Premature Spindle Breakage during Mitotic Exit. PLoS Genet 2016; 12:e1006195. [PMID: 27447488 PMCID: PMC4957831 DOI: 10.1371/journal.pgen.1006195] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 06/23/2016] [Indexed: 11/30/2022] Open
Abstract
Cytokinesis requires the spatio-temporal coordination of membrane deposition and primary septum (PS) formation at the division site to drive acto-myosin ring (AMR) constriction. It has been demonstrated that AMR constriction invariably occurs only after the mitotic spindle disassembly. It has also been established that Chitin Synthase II (Chs2p) neck localization precedes mitotic spindle disassembly during mitotic exit. As AMR constriction depends upon PS formation, the question arises as to how chitin deposition is regulated so as to prevent premature AMR constriction and mitotic spindle breakage. In this study, we propose that cells regulate the coordination between spindle disassembly and AMR constriction via timely endocytosis of cytokinetic enzymes, Chs2p, Chs3p, and Fks1p. Inhibition of endocytosis leads to over accumulation of cytokinetic enzymes during mitotic exit, which accelerates the constriction of the AMR, and causes spindle breakage that eventually could contribute to monopolar spindle formation in the subsequent round of cell division. Intriguingly, the mitotic spindle breakage observed in endocytosis mutants can be rescued either by deleting or inhibiting the activities of, CHS2, CHS3 and FKS1, which are involved in septum formation. The findings from our study highlight the importance of timely endocytosis of cytokinetic enzymes at the division site in safeguarding mitotic spindle integrity during mitotic exit. The cytokinesis machinery that is required for physical separation of mother-daughter cells during mitosis is highly conserved from yeast to humans. In budding yeast, cytokinesis is achieved via timely delivery of cytokinetic enzymes to the division site that eventually triggers the constriction of AMR. It has been previously demonstrated that cytokinesis invariably occurs after the disassembly of the mitotic spindle. Intriguingly, Chs2p that is responsible for laying down the primary septum has been shown to localize to the division site before mitotic spindle disassembly. In this study, we show that mitotic spindle integrity upon sister chromatid separation is dependent on the continuous endocytosis of cytokinetic enzymes. Failure in the internalization of cytokinetic proteins during mitotic exit causes premature AMR constriction that eventually contributes to the shearing of mitotic spindle. Consequently, cells fail to re-establish a bipolar spindle in the subsequent round of cell division cycle. Our findings provide insights into how the levels of secreted proteins at the division site impacts cytokinesis. We believe this regulation mechanism might be conserved in higher eukaryotic cells as a secreted protein, hemicentin, has been shown recently to be involved in regulating cytokinesis in both Caenorhabditis elegans and mouse embryos.
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Affiliation(s)
- Cheen Fei Chin
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Kaiquan Tan
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Masayuki Onishi
- Department of Genetics, Stanford University School of Medicine, Stanford, California, United States of America
| | - YuanYuan Chew
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Beryl Augustine
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Wei Ren Lee
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Foong May Yeong
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
- * E-mail:
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25
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Finnigan GC, Duvalyan A, Liao EN, Sargsyan A, Thorner J. Detection of protein-protein interactions at the septin collar in Saccharomyces cerevisiae using a tripartite split-GFP system. Mol Biol Cell 2016; 27:2708-25. [PMID: 27385335 PMCID: PMC5007091 DOI: 10.1091/mbc.e16-05-0337] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 06/30/2016] [Indexed: 01/22/2023] Open
Abstract
A tripartite split-GFP system faithfully reports the order of the subunits in septin hetero-octamers (and thus can serve as a “molecular ruler”), conversely yields little or no false signal even with very highly expressed cytosolic proteins, and detects authentic interactions of other cellular proteins that are bona fide septin-binding proteins. Various methods can provide a readout of the physical interaction between two biomolecules. A recently described tripartite split-GFP system has the potential to report by direct visualization via a fluorescence signal the intimate association of minimally tagged proteins expressed at their endogenous level in their native cellular milieu and can capture transient or weak interactions. Here we document the utility of this tripartite split-GFP system to assess in living cells protein–protein interactions in a dynamic cytoskeletal structure—the septin collar at the yeast bud neck. We show, first, that for septin–septin interactions, this method yields a robust signal whose strength reflects the known spacing between the subunits in septin filaments and thus serves as a “molecular ruler.” Second, the method yields little or no spurious signal even with highly abundant cytosolic proteins readily accessible to the bud neck (including molecular chaperone Hsp82 and glycolytic enzyme Pgk1). Third, using two proteins (Bni5 and Hsl1) that have been shown by other means to bind directly to septins at the bud neck in vivo, we validate that the tripartite split-GFP method yields the same conclusions and further insights about specificity. Finally, we demonstrate the capacity of this approach to uncover additional new information by examining whether three other proteins reported to localize to the bud neck (Nis1, Bud4, and Hof1) are able to interact physically with any of the subunits in the septin collar and, if so, with which ones.
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Affiliation(s)
- Gregory C Finnigan
- Division of Biochemistry, Biophysics and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720-3202
| | - Angela Duvalyan
- Division of Biochemistry, Biophysics and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720-3202
| | - Elizabeth N Liao
- Division of Biochemistry, Biophysics and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720-3202
| | - Aspram Sargsyan
- Division of Biochemistry, Biophysics and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720-3202
| | - Jeremy Thorner
- Division of Biochemistry, Biophysics and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720-3202
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26
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Abstract
As cells grow, move, and divide, they must reorganize and rearrange their membranes and cytoskeleton. The F-BAR protein family links cellular membranes with actin cytoskeletal rearrangements in processes including endocytosis, cytokinesis, and cell motility. Here we review emerging information on mechanisms of F-BAR domain oligomerization and membrane binding, and how these activities are coordinated with additional domains to accomplish scaffolding and signaling functions.
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Affiliation(s)
- Nathan A McDonald
- a Department of Cell and Developmental Biology , Vanderbilt University , Nashville , TN , USA
| | - Kathleen L Gould
- a Department of Cell and Developmental Biology , Vanderbilt University , Nashville , TN , USA
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27
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Foltman M, Molist I, Arcones I, Sacristan C, Filali-Mouncef Y, Roncero C, Sanchez-Diaz A. Ingression Progression Complexes Control Extracellular Matrix Remodelling during Cytokinesis in Budding Yeast. PLoS Genet 2016; 12:e1005864. [PMID: 26891268 PMCID: PMC4758748 DOI: 10.1371/journal.pgen.1005864] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Accepted: 01/22/2016] [Indexed: 12/02/2022] Open
Abstract
Eukaryotic cells must coordinate contraction of the actomyosin ring at the division site together with ingression of the plasma membrane and remodelling of the extracellular matrix (ECM) to support cytokinesis, but the underlying mechanisms are still poorly understood. In eukaryotes, glycosyltransferases that synthesise ECM polysaccharides are emerging as key factors during cytokinesis. The budding yeast chitin synthase Chs2 makes the primary septum, a special layer of the ECM, which is an essential process during cell division. Here we isolated a group of actomyosin ring components that form complexes together with Chs2 at the cleavage site at the end of the cell cycle, which we named ‘ingression progression complexes’ (IPCs). In addition to type II myosin, the IQGAP protein Iqg1 and Chs2, IPCs contain the F-BAR protein Hof1, and the cytokinesis regulators Inn1 and Cyk3. We describe the molecular mechanism by which chitin synthase is activated by direct association of the C2 domain of Inn1, and the transglutaminase-like domain of Cyk3, with the catalytic domain of Chs2. We used an experimental system to find a previously unanticipated role for the C-terminus of Inn1 in preventing the untimely activation of Chs2 at the cleavage site until Cyk3 releases the block on Chs2 activity during late mitosis. These findings support a model for the co-ordinated regulation of cell division in budding yeast, in which IPCs play a central role. Cytokinesis is the process by which a cell divides in two and occurs once cells have replicated and segregated their chromosomes. Eukaryotic cells assemble a molecular machine called the actomyosin ring that drives cytokinesis. Contraction of the actomyosin ring is coupled to ingression of the plasma membrane and extracellular matrix remodelling. In eukaryotes, glycosyltransferases that synthesise polysaccharides of the extracellular matrix are emerging as essential factors during cytokinesis. Defects associated with the function of those glycosyltransferases induce the failure of cell division, which promotes the formation of genetically unstable tetraploid cells. Budding yeast cells contain a glycosyltransferase called Chs2 that makes a special layer of extracellular matrix and is essential during cell division. Our findings provide new insights into the molecular mechanism by which the cytokinesis regulators Inn1 and Cyk3 finely regulate the activity of glycosyltransferase Chs2 at the end of mitosis. In addition we isolated a group of actomyosin ring components that form complexes together with Chs2 and Inn1 at the cleavage site, which we have named ‘ingression progression complexes’. These complexes coordinate the contraction of the actomyosin ring, ingression of the plasma membrane and extracellular matrix remodelling in a precise manner. Chs2 is indeed a key factor for coordinating these events. It appears that similar principles could apply to other eukaryotic species, such as fission yeast even if the identity of the relevant glycosyltransferase has changed over the evolution. Taking into account the conservation of the basic cytokinetic mechanisms future studies should try to determine whether a glycosyltransferase similar to Chs2 plays a key role during cytokinesis in human cells.
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Affiliation(s)
- Magdalena Foltman
- Instituto de Biomedicina y Biotecnología de Cantabria, Universidad de Cantabria, CSIC, Santander, Spain
- Departamento de Biología Molecular, Facultad de Medicina, Universidad de Cantabria, Santander, Spain
| | - Iago Molist
- Instituto de Biomedicina y Biotecnología de Cantabria, Universidad de Cantabria, CSIC, Santander, Spain
- Departamento de Biología Molecular, Facultad de Medicina, Universidad de Cantabria, Santander, Spain
| | - Irene Arcones
- Instituto de Biología Funcional y Genómica, Departamento de Microbiología y Genética, CSIC, Universidad de Salamanca, Salamanca, Spain
| | - Carlos Sacristan
- Instituto de Biología Funcional y Genómica, Departamento de Microbiología y Genética, CSIC, Universidad de Salamanca, Salamanca, Spain
| | - Yasmina Filali-Mouncef
- Instituto de Biomedicina y Biotecnología de Cantabria, Universidad de Cantabria, CSIC, Santander, Spain
- Departamento de Biología Molecular, Facultad de Medicina, Universidad de Cantabria, Santander, Spain
| | - Cesar Roncero
- Instituto de Biología Funcional y Genómica, Departamento de Microbiología y Genética, CSIC, Universidad de Salamanca, Salamanca, Spain
| | - Alberto Sanchez-Diaz
- Instituto de Biomedicina y Biotecnología de Cantabria, Universidad de Cantabria, CSIC, Santander, Spain
- Departamento de Biología Molecular, Facultad de Medicina, Universidad de Cantabria, Santander, Spain
- * E-mail:
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Abstract
Cytokinesis is the final process in the cell cycle that physically divides one cell into two. In budding yeast, cytokinesis is driven by a contractile actomyosin ring (AMR) and the simultaneous formation of a primary septum, which serves as template for cell wall deposition. AMR assembly, constriction, primary septum formation and cell wall deposition are successive processes and tightly coupled to cell cycle progression to ensure the correct distribution of genetic material and cell organelles among the two rising cells prior to cell division. The role of the AMR in cytokinesis and the molecular mechanisms that drive AMR constriction and septation are the focus of current research. This review summarizes the recent progresses in our understanding of how budding yeast cells orchestrate the multitude of molecular mechanisms that control AMR driven cytokinesis in a spatio-temporal manner to achieve an error free cell division.
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McDonald NA, Takizawa Y, Feoktistova A, Xu P, Ohi MD, Vander Kooi CW, Gould KL. The Tubulation Activity of a Fission Yeast F-BAR Protein Is Dispensable for Its Function in Cytokinesis. Cell Rep 2016; 14:534-546. [PMID: 26776521 PMCID: PMC4731314 DOI: 10.1016/j.celrep.2015.12.062] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Revised: 11/23/2015] [Accepted: 12/10/2015] [Indexed: 11/28/2022] Open
Abstract
F-BAR proteins link cellular membranes to the actin cytoskeleton in many biological processes. Here we investigated the function of the Schizosaccharomyces pombe Imp2 F-BAR domain in cytokinesis and find that it is critical for Imp2's role in contractile ring constriction and disassembly. To understand mechanistically how the F-BAR domain functions, we determined its structure, elucidated how it interacts with membranes, and identified an interaction between dimers that allows helical oligomerization and membrane tubulation. Using mutations that block either membrane binding or tubulation, we find that membrane binding is required for Imp2's cytokinetic function but that oligomerization and tubulation, activities often deemed central to F-BAR protein function, are dispensable. Accordingly, F-BARs that do not have the capacity to tubulate membranes functionally substitute for the Imp2 F-BAR, establishing that its major role is as a cell-cycle-regulated bridge between the membrane and Imp2 protein partners, rather than as a driver of membrane curvature.
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Affiliation(s)
- Nathan A McDonald
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37240, USA
| | - Yoshimasa Takizawa
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37240, USA; Center for Structural Biology, Vanderbilt University, Nashville, TN 37240, USA
| | - Anna Feoktistova
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37240, USA
| | - Ping Xu
- Department of Molecular and Cellular Biochemistry and Center for Structural Biology, University of Kentucky, Lexington, KY 40536, USA
| | - Melanie D Ohi
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37240, USA; Center for Structural Biology, Vanderbilt University, Nashville, TN 37240, USA
| | - Craig W Vander Kooi
- Department of Molecular and Cellular Biochemistry and Center for Structural Biology, University of Kentucky, Lexington, KY 40536, USA
| | - Kathleen L Gould
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37240, USA.
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Abstract
Multiple membrane-binding proteins are key players in cytokinesis in yeast and other organisms. In vivo techniques for analyzing protein-membrane interactions are currently limited. In vitro assays allow characterization of the biochemical properties of these proteins to build a mechanistic understanding of protein-membrane interactions during cytokinesis. Here, we describe two in vitro assays to characterize FCH-Bin/Amphyphysin/RVS (F-BAR) domains and other protein's interactions with membranes: liposome co-pelleting and giant unilamellar vesicle fluorescent binding.
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Affiliation(s)
- Nathan A McDonald
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, 465 21st Ave S., Nashville, TN, 37240-7935, USA
| | - Kathleen L Gould
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, 465 21st Ave S., Nashville, TN, 37240-7935, USA.
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Miller DP, Hall H, Chaparian R, Mara M, Mueller A, Hall MC, Shannon KB. Dephosphorylation of Iqg1 by Cdc14 regulates cytokinesis in budding yeast. Mol Biol Cell 2015; 26:2913-26. [PMID: 26085509 PMCID: PMC4571329 DOI: 10.1091/mbc.e14-12-1637] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Revised: 06/08/2015] [Accepted: 06/09/2015] [Indexed: 01/11/2023] Open
Abstract
Cytokinesis separates cells by contraction of a ring composed of filamentous actin (F-actin) and type II myosin. Iqg1, an IQGAP family member, is an essential protein in Saccharomyces cerevisiae required for assembly and contraction of the actomyosin ring. Localization of F-actin to the ring occurs only after anaphase and is mediated by the calponin homology domain (CHD) of Iqg1, but the regulatory mechanisms that temporally restrict actin ring assembly are not well defined. We tested the hypothesis that dephosphorylation of four perfect cyclin-dependent kinase (Cdk) sites flanking the CHD promotes actin ring formation, using site-specific alanine mutants. Cells expressing the nonphosphorylatable iqg1-4A allele formed actin rings before anaphase and exhibited defects in myosin contraction and cytokinesis. The Cdc14 phosphatase is required for normal cytokinesis and acts on specific Cdk phosphorylation sites. Overexpression of Cdc14 resulted in premature actin ring assembly, whereas inhibition of Cdc14 function prevented actin ring formation. Cdc14 associated with Iqg1, dependent on several CHD-flanking Cdk sites, and efficiently dephosphorylated these sites in vitro. Of importance, the iqg1-4A mutant rescued the inability of cdc14-1 cells to form actin rings. Our data support a model in which dephosphorylation of Cdk sites around the Iqg1 CHD by Cdc14 is both necessary and sufficient to promote actin ring formation. Temporal control of actin ring assembly by Cdk and Cdc14 may help to ensure that cytokinesis onset occurs after nuclear division is complete.
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Affiliation(s)
- Daniel P. Miller
- Department of Biological Sciences, Missouri University of Science and Technology, Rolla, MO 65401
| | - Hana Hall
- Department of Biochemistry, Purdue Center for Cancer Research, Purdue University, West Lafayette, IN 47907
| | - Ryan Chaparian
- Department of Biochemistry, Purdue Center for Cancer Research, Purdue University, West Lafayette, IN 47907
| | - Madison Mara
- Department of Biological Sciences, Missouri University of Science and Technology, Rolla, MO 65401
| | - Alison Mueller
- Department of Biological Sciences, Missouri University of Science and Technology, Rolla, MO 65401
| | - Mark C. Hall
- Department of Biochemistry, Purdue Center for Cancer Research, Purdue University, West Lafayette, IN 47907
| | - Katie B. Shannon
- Department of Biological Sciences, Missouri University of Science and Technology, Rolla, MO 65401
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Finnigan GC, Takagi J, Cho C, Thorner J. Comprehensive Genetic Analysis of Paralogous Terminal Septin Subunits Shs1 and Cdc11 in Saccharomyces cerevisiae. Genetics 2015; 200:821-41. [PMID: 25971665 PMCID: PMC4512546 DOI: 10.1534/genetics.115.176495] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Accepted: 05/08/2015] [Indexed: 02/07/2023] Open
Abstract
Septins are a family of GTP-binding proteins considered to be cytoskeletal elements because they self-assemble into filaments and other higher-order structures in vivo. In budding yeast, septins establish a diffusion barrier at the bud neck between a mother and daughter cell, promote membrane curvature there, and serve as a scaffold to recruit other proteins to the site of cytokinesis. However, the mechanism by which any septin engages a partner protein has been unclear. The two most related and recently evolved subunits appear to be Cdc11 and Shs1, and the basic building blocks for assembling septin structures are hetero-octameric rods (Cdc11-Cdc12-Cdc3-Cdc10-Cdc10-Cdc3-Cdc12-Cdc11 and Shs1-Cdc12-Cdc3-Cdc10-Cdc10-Cdc3-Cdc12-Shs1). Loss of Cdc11 is not normally tolerated, whereas cells lacking Shs1 do not appear grossly abnormal. We established several different sensitized genetic backgrounds wherein Shs1 is indispensable, which allowed us to carry out the first comprehensive and detailed genetic analysis of Shs1 in vivo. Our analysis revealed several novel insights, including: (i) the sole portion of Shs1 essential for its function is a predicted coiled-coil-forming segment in its C-terminal extension (CTE); (ii) the CTE of Cdc11 shares this function; (iii) this role for the CTEs of Cdc11 and Shs1 is quite distinct from that of the CTEs of Cdc3 and Cdc12; and (iv) heterotypic Cdc11 and Shs1 junctions likely occur in vivo.
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Affiliation(s)
- Gregory C Finnigan
- Division of Biochemistry, Biophysics and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, California 94720-3202
| | - Julie Takagi
- Department of Microbiology and Immunology, University of California School of Medicine, San Francisco, California 94158-2200
| | - Christina Cho
- Harvard School of Dental Medicine, Boston, Massachusetts 02115
| | - Jeremy Thorner
- Division of Biochemistry, Biophysics and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, California 94720-3202 Department of Microbiology and Immunology, University of California School of Medicine, San Francisco, California 94158-2200 Harvard School of Dental Medicine, Boston, Massachusetts 02115
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33
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G. Cortés JC, Pujol N, Sato M, Pinar M, Ramos M, Moreno B, Osumi M, Ribas JC, Pérez P. Cooperation between Paxillin-like Protein Pxl1 and Glucan Synthase Bgs1 Is Essential for Actomyosin Ring Stability and Septum Formation in Fission Yeast. PLoS Genet 2015; 11:e1005358. [PMID: 26132084 PMCID: PMC4489101 DOI: 10.1371/journal.pgen.1005358] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Accepted: 06/13/2015] [Indexed: 01/19/2023] Open
Abstract
In fungal cells cytokinesis requires coordinated closure of a contractile actomyosin ring (CAR) and synthesis of a special cell wall structure known as the division septum. Many CAR proteins have been identified and characterized, but how these molecules interact with the septum synthesis enzymes to form the septum remains unclear. Our genetic study using fission yeast shows that cooperation between the paxillin homolog Pxl1, required for ring integrity, and Bgs1, the enzyme responsible for linear β(1,3)glucan synthesis and primary septum formation, is required for stable anchorage of the CAR to the plasma membrane before septation onset, and for cleavage furrow formation. Thus, lack of Pxl1 in combination with Bgs1 depletion, causes failure of ring contraction and lateral cell wall overgrowth towards the cell lumen without septum formation. We also describe here that Pxl1 concentration at the CAR increases during cytokinesis and that this increase depends on the SH3 domain of the F-BAR protein Cdc15. In consequence, Bgs1 depletion in cells carrying a cdc15ΔSH3 allele causes ring disassembly and septation blockage, as it does in cells lacking Pxl1. On the other hand, the absence of Pxl1 is lethal when Cdc15 function is affected, generating a large sliding of the CAR with deposition of septum wall material along the cell cortex, and suggesting additional functions for both Pxl1 and Cdc15 proteins. In conclusion, our findings indicate that CAR anchorage to the plasma membrane through Cdc15 and Pxl1, and concomitant Bgs1 activity, are necessary for CAR maintenance and septum formation in fission yeast. Cytokinesis requires assembly of an actomyosin ring adjacent to the plasma membrane, which upon contraction pulls the membrane to form a cleavage furrow. In fungi ring closure is coordinated with the synthesis of a cell wall septum. Knowledge about the molecules anchoring the ring to the membrane is very limited. We have found that fission yeast paxillin, located at the ring, and Bgs1, the enzyme responsible for primary septum formation, located at the membrane, cooperate during cytokinesis. Both are required to anchor the ring to the membrane and to maintain it during cytokinesis. Moreover, both proteins cooperate to form the septum. Accordingly, paxillin is essential when Bgs1 is depleted. When both proteins are missing, the contractile ring forms but the lateral cell wall overgrows inwards without a defined cleavage furrow and septum formation. During cytokinesis there is an increase of paxillin which depends on the SH3 domain of the F-BAR protein Cdc15. Consequently the absence of this domain mimics the phenotype of paxillin absence in Bgs1-depleted cells. Interestingly, a decreased function of both Cdc15 and paxillin uncouples the septum synthesis from the ring contraction, indicating an essential cooperation between these proteins and Bgs1 for proper cytokinesis.
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Affiliation(s)
- Juan C. G. Cortés
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas (CSIC) / Universidad de Salamanca, Salamanca, Spain
- * E-mail:
| | - Nuria Pujol
- Department of Ciències Mèdiques, Bàsiques,Institut de Recerca Biomèdica (IRB) de Lleida, Faculty of Medicine, University of Lleida, Lleida, Spain
| | - Mamiko Sato
- Laboratory of Electron Microscopy/Open Research Centre, and Department of Chemical and Biological Sciences, Japan Women’s University, Mejirodai, Bunkyo-ku, Tokyo, Japan
| | - Mario Pinar
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
| | - Mariona Ramos
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas (CSIC) / Universidad de Salamanca, Salamanca, Spain
| | - Belén Moreno
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas (CSIC) / Universidad de Salamanca, Salamanca, Spain
| | - Masako Osumi
- Laboratory of Electron Microscopy/Open Research Centre, and Department of Chemical and Biological Sciences, Japan Women’s University, Mejirodai, Bunkyo-ku, Tokyo, Japan
| | - Juan Carlos Ribas
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas (CSIC) / Universidad de Salamanca, Salamanca, Spain
| | - Pilar Pérez
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas (CSIC) / Universidad de Salamanca, Salamanca, Spain
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The Carboxy-Terminal Tails of Septins Cdc11 and Shs1 Recruit Myosin-II Binding Factor Bni5 to the Bud Neck in Saccharomyces cerevisiae. Genetics 2015; 200:843-62. [PMID: 25971666 DOI: 10.1534/genetics.115.176503] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Accepted: 05/08/2015] [Indexed: 12/20/2022] Open
Abstract
UNLABELLED Septins are a conserved family of GTP-binding proteins that form heterooctameric complexes that assemble into higher-order structures. In yeast, septin superstructure at the bud neck serves as a barrier to separate a daughter cell from its mother and as a scaffold to recruit the proteins that execute cytokinesis. However, how septins recruit specific factors has not been well characterized. In the accompanying article in this issue, (Finnigan et al. 2015), we demonstrated that the C-terminal extensions (CTEs) of the alternative terminal subunits of septin heterooctamers, Cdc11 and Shs1, share a role required for optimal septin function in vivo. Here we describe our use of unbiased genetic approaches (both selection of dosage suppressors and analysis of synthetic interactions) that pinpointed Bni5 as a protein that interacts with the CTEs of Cdc11 and Shs1. Furthermore, we used three independent methods-construction of chimeric proteins, noncovalent tethering mediated by a GFP-targeted nanobody, and imaging by fluorescence microscopy-to confirm that a physiologically important function of the CTEs of Cdc11 and Shs1 is optimizing recruitment of Bni5 and thereby ensuring efficient localization at the bud neck of Myo1, the type II myosin of the actomyosin contractile ring.Related article in GENETICS Finnigan, G. C. et al., 2015 Comprehensive Genetic Analysis of Paralogous Terminal Septin Subunits Shs1 and Cdc11 in Saccharomyces cerevisiae. Genetics 200: 841-861.
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35
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Roelants FM, Su BM, von Wulffen J, Ramachandran S, Sartorel E, Trott AE, Thorner J. Protein kinase Gin4 negatively regulates flippase function and controls plasma membrane asymmetry. ACTA ACUST UNITED AC 2015; 208:299-311. [PMID: 25646086 PMCID: PMC4315245 DOI: 10.1083/jcb.201410076] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In yeast, the protein kinase Gin4 locally controls plasma membrane lipid asymmetry, which is necessary for optimal cytokinesis. Plasma membrane function requires distinct leaflet lipid compositions. Two of the P-type ATPases (flippases) in yeast, Dnf1 and Dnf2, translocate aminoglycerophospholipids from the outer to the inner leaflet, stimulated via phosphorylation by cortically localized protein kinase Fpk1. By monitoring Fpk1 activity in vivo, we found that Fpk1 was hyperactive in cells lacking Gin4, a protein kinase previously implicated in septin collar assembly. Gin4 colocalized with Fpk1 at the cortical site of future bud emergence and phosphorylated Fpk1 at multiple sites, which we mapped. As judged by biochemical and phenotypic criteria, a mutant (Fpk111A), in which 11 sites were mutated to Ala, was hyperactive, causing increased inward transport of phosphatidylethanolamine. Thus, Gin4 is a negative regulator of Fpk1 and therefore an indirect negative regulator of flippase function. Moreover, we found that decreasing flippase function rescued the growth deficiency of four different cytokinesis mutants, which suggests that the primary function of Gin4 is highly localized control of membrane lipid asymmetry and is necessary for optimal cytokinesis.
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Affiliation(s)
- Françoise M Roelants
- Division of Biochemistry, Biophysics and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720
| | - Brooke M Su
- Division of Biochemistry, Biophysics and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720
| | - Joachim von Wulffen
- Division of Biochemistry, Biophysics and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720
| | - Subramaniam Ramachandran
- Division of Biochemistry, Biophysics and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720
| | - Elodie Sartorel
- Division of Biochemistry, Biophysics and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720
| | - Amy E Trott
- Division of Biochemistry, Biophysics and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720
| | - Jeremy Thorner
- Division of Biochemistry, Biophysics and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720
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36
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Feng Z, Okada S, Cai G, Zhou B, Bi E. Myosin‑II heavy chain and formin mediate the targeting of myosin essential light chain to the division site before and during cytokinesis. Mol Biol Cell 2015; 26:1211-24. [PMID: 25631819 PMCID: PMC4454170 DOI: 10.1091/mbc.e14-09-1363] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
MLC1 is a haploinsufficient gene encoding the essential light chain for Myo1, the sole myosin‑II heavy chain in the budding yeast Saccharomyces cerevisiae. Mlc1 defines an essential hub that coordinates actomyosin ring function, membrane trafficking, and septum formation during cytokinesis by binding to IQGAP, myosin‑II, and myosin‑V. However, the mechanism of how Mlc1 is targeted to the division site during the cell cycle remains unsolved. By constructing a GFP‑tagged MLC1 under its own promoter control and using quantitative live‑cell imaging coupled with yeast mutants, we found that septin ring and actin filaments mediate the targeting of Mlc1 to the division site before and during cytokinesis, respectively. Both mechanisms contribute to and are collectively required for the accumulation of Mlc1 at the division site during cytokinesis. We also found that Myo1 plays a major role in the septin‑dependent Mlc1 localization before cytokinesis, whereas the formin Bni1 plays a major role in the actin filament-dependent Mlc1 localization during cytokinesis. Such a two‑tiered mechanism for Mlc1 localization is presumably required for the ordered assembly and robustness of cytokinesis machinery and is likely conserved across species.
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Affiliation(s)
- Zhonghui Feng
- School of Life Sciences, Tsinghua University, Beijing 100084, China Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Satoshi Okada
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Guoping Cai
- School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Bing Zhou
- School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Erfei Bi
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
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37
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Moravcevic K, Alvarado D, Schmitz KR, Kenniston JA, Mendrola JM, Ferguson KM, Lemmon MA. Comparison of Saccharomyces cerevisiae F-BAR domain structures reveals a conserved inositol phosphate binding site. Structure 2015; 23:352-63. [PMID: 25620000 DOI: 10.1016/j.str.2014.12.009] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Revised: 11/29/2014] [Accepted: 12/02/2014] [Indexed: 12/27/2022]
Abstract
F-BAR domains control membrane interactions in endocytosis, cytokinesis, and cell signaling. Although they are generally thought to bind curved membranes containing negatively charged phospholipids, numerous functional studies argue that differences in lipid-binding selectivities of F-BAR domains are functionally important. Here, we compare membrane-binding properties of the Saccharomyces cerevisiae F-BAR domains in vitro and in vivo. Whereas some F-BAR domains (such as Bzz1p and Hof1p F-BARs) bind equally well to all phospholipids, the F-BAR domain from the RhoGAP Rgd1p preferentially binds phosphoinositides. We determined X-ray crystal structures of F-BAR domains from Hof1p and Rgd1p, the latter bound to an inositol phosphate. The structures explain phospholipid-binding selectivity differences and reveal an F-BAR phosphoinositide binding site that is fully conserved in a mammalian RhoGAP called Gmip and is partly retained in certain other F-BAR domains. Our findings reveal previously unappreciated determinants of F-BAR domain lipid-binding specificity and provide a basis for its prediction from sequence.
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Affiliation(s)
- Katarina Moravcevic
- Department of Biochemistry and Biophysics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19014, USA; Graduate Group in Biochemistry and Molecular Biophysics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19014, USA
| | - Diego Alvarado
- Department of Biochemistry and Biophysics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19014, USA
| | - Karl R Schmitz
- Graduate Group in Biochemistry and Molecular Biophysics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19014, USA; Department of Physiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19014, USA
| | - Jon A Kenniston
- Department of Biochemistry and Biophysics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19014, USA
| | - Jeannine M Mendrola
- Department of Biochemistry and Biophysics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19014, USA
| | - Kathryn M Ferguson
- Graduate Group in Biochemistry and Molecular Biophysics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19014, USA; Department of Physiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19014, USA
| | - Mark A Lemmon
- Department of Biochemistry and Biophysics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19014, USA; Graduate Group in Biochemistry and Molecular Biophysics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19014, USA.
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38
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Ren L, Willet AH, Roberts-Galbraith RH, McDonald NA, Feoktistova A, Chen JS, Huang H, Guillen R, Boone C, Sidhu SS, Beckley JR, Gould KL. The Cdc15 and Imp2 SH3 domains cooperatively scaffold a network of proteins that redundantly ensure efficient cell division in fission yeast. Mol Biol Cell 2014; 26:256-69. [PMID: 25428987 PMCID: PMC4294673 DOI: 10.1091/mbc.e14-10-1451] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The fission yeast F-BAR proteins Cdc15 and Imp2 and their combined SH3-domain partners appear to act as “molecular glue” to stabilize the interaction between the plasma membrane and a complex network of proteins at the division site that mediates cell division. Schizosaccharomyces pombe cdc15 homology (PCH) family members participate in numerous biological processes, including cytokinesis, typically by bridging the plasma membrane via their F-BAR domains to the actin cytoskeleton. Two SH3 domain–containing PCH family members, Cdc15 and Imp2, play critical roles in S. pombe cytokinesis. Although both proteins localize to the contractile ring, with Cdc15 preceding Imp2, only cdc15 is an essential gene. Despite these distinct roles, the SH3 domains of Cdc15 and Imp2 cooperate in the essential process of recruiting other proteins to stabilize the contractile ring. To better understand the connectivity of this SH3 domain–based protein network at the CR and its function, we used a biochemical approach coupled to proteomics to identify additional proteins (Rgf3, Art1, Spa2, and Pos1) that are integrated into this network. Cell biological and genetic analyses of these SH3 partners implicate them in a range of activities that ensure the fidelity of cell division, including promoting cell wall metabolism and influencing cell morphogenesis.
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Affiliation(s)
- Liping Ren
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Alaina H Willet
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Rachel H Roberts-Galbraith
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Nathan A McDonald
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Anna Feoktistova
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Jun-Song Chen
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Haiming Huang
- Terrence Donnelly Center for Cellular and Biomolecular Research, Banting and Best Department of Medical Research, University of Toronto, Toronto, ON M5G 1L6, Canada
| | - Rodrigo Guillen
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Charles Boone
- Terrence Donnelly Center for Cellular and Biomolecular Research, Banting and Best Department of Medical Research, University of Toronto, Toronto, ON M5G 1L6, Canada
| | - Sachdev S Sidhu
- Terrence Donnelly Center for Cellular and Biomolecular Research, Banting and Best Department of Medical Research, University of Toronto, Toronto, ON M5G 1L6, Canada
| | - Janel R Beckley
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Kathleen L Gould
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232
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39
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Kuilman T, Maiolica A, Godfrey M, Scheidel N, Aebersold R, Uhlmann F. Identification of Cdk targets that control cytokinesis. EMBO J 2014; 34:81-96. [PMID: 25371407 PMCID: PMC4291482 DOI: 10.15252/embj.201488958] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The final event of the eukaryotic cell cycle is cytokinesis, when two new daughter cells are born. How the timing and execution of cytokinesis is controlled is poorly understood. Here, we show that downregulation of cyclin-dependent kinase (Cdk) activity, together with upregulation of its counteracting phosphatase Cdc14, controls each of the sequential steps of cytokinesis, including furrow ingression, membrane resolution and cell separation in budding yeast. We use phosphoproteome analysis of mitotic exit to identify Cdk targets that are dephosphorylated at the time of cytokinesis. We then apply a new and widely applicable tool to generate conditionally phosphorylated proteins to identify those whose dephosphorylation is required for cytokinesis. This approach identifies Aip1, Ede1 and Inn1 as cytokinetic regulators. Our results suggest that cytokinesis is coordinately controlled by the master cell cycle regulator Cdk together with its counteracting phosphatase and that it is executed by concerted dephosphorylation of Cdk targets involved in several cell biological processes.
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Affiliation(s)
- Thomas Kuilman
- Chromosome Segregation Laboratory, Cancer Research UK London Research Institute Lincoln's Inn Fields Laboratories, London, UK
| | - Alessio Maiolica
- Department of Biology, Institute of Molecular Systems Biology, Eidgenössische Technische Hochschule (ETH) Zürich, Zurich, Switzerland
| | - Molly Godfrey
- Chromosome Segregation Laboratory, Cancer Research UK London Research Institute Lincoln's Inn Fields Laboratories, London, UK
| | - Noémie Scheidel
- Chromosome Segregation Laboratory, Cancer Research UK London Research Institute Lincoln's Inn Fields Laboratories, London, UK
| | - Ruedi Aebersold
- Department of Biology, Institute of Molecular Systems Biology, Eidgenössische Technische Hochschule (ETH) Zürich, Zurich, Switzerland Faculty of Science, University of Zurich, Zurich, Switzerland
| | - Frank Uhlmann
- Chromosome Segregation Laboratory, Cancer Research UK London Research Institute Lincoln's Inn Fields Laboratories, London, UK
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40
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Rippert D, Heppeler N, Albermann S, Schmitz HP, Heinisch JJ. Regulation of cytokinesis in the milk yeast Kluyveromyces lactis. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1843:2685-97. [PMID: 25110348 DOI: 10.1016/j.bbamcr.2014.07.020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Revised: 07/28/2014] [Accepted: 07/30/2014] [Indexed: 10/24/2022]
Abstract
Cytokinesis in yeast and mammalian cells is a highly coordinated process mediated by the constriction of an actomyosin ring. In yeasts, it is accompanied by the formation of a chitinous primary septum. Although much is known about the regulation of cytokinesis in budding yeast, overlapping functions of redundant genes complicates genetic analyses. Here, we investigated the effects of various deletion mutants on cytokinesis in the milk yeast Kluyveromyces lactis. To determine the spatiotemporal parameters of cytokinesis components, live-cell imaging of fluorophor-tagged KlMyo1 and a new Lifeact probe for KlAct1 was employed. In contrast to Saccharomyces cerevisiae, where deletion of ScMYO1 is lethal, Klmyo1 deletion was temperature-sensitive. Transmission and scanning electron microscopy demonstrated that the Klmyo1 deletion cells had a defect in the formation of the primary septum and in cell separation; this result was confirmed by FACS analyses. Deletion of KlCYK3 was lethal, whereas in S. cerevisiae a cyk3 deletion is synthetically lethal with hof1 deletion. Growth of Klhof1 mutants was osmoremedial at 25°C, as it is in S. cerevisiae. CYK3 and HOF1 genes cross-complemented in both species, suggesting that they are functional homologs. Inn1, a common interactor for these two regulators, was essential in both yeasts and the encoding genes did not cross-complement. The C2 domain of the Inn1 homologs conferred species specificity. Thus, our work establishes K. lactis as a model yeast to study cytokinesis with less genetic redundancy than S. cerevisiae. The viability of Klmyo1 deletions provides an advantage over budding yeast to study actomyosin-independent cytokinesis. Moreover, the lethality of Klcyk3 null mutants suggests that there are fewer functional redundancies with KlHof1 in K. lactis.
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Affiliation(s)
- Dorthe Rippert
- Universität Osnabrück, Fachbereich Biologie/Chemie, AG Genetik, 49076 Osnabrück, Germany
| | - Nele Heppeler
- Universität Osnabrück, Fachbereich Biologie/Chemie, AG Genetik, 49076 Osnabrück, Germany
| | - Sabine Albermann
- Universität Osnabrück, Fachbereich Biologie/Chemie, AG Genetik, 49076 Osnabrück, Germany
| | - Hans-Peter Schmitz
- Universität Osnabrück, Fachbereich Biologie/Chemie, AG Genetik, 49076 Osnabrück, Germany
| | - Jürgen J Heinisch
- Universität Osnabrück, Fachbereich Biologie/Chemie, AG Genetik, 49076 Osnabrück, Germany.
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41
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Tian C, Wu Y, Johnsson N. Stepwise and cooperative assembly of a cytokinetic core complex in Saccharomyces cerevisiae. J Cell Sci 2014; 127:3614-24. [PMID: 24895401 DOI: 10.1242/jcs.153429] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Actomyosin ring (AMR) contraction and the synthesis of an extracellular septum are interdependent pathways that mediate cytokinesis in the yeast Saccharomyces cerevisiae and other eukaryotes. How these interdependent pathways are physically connected is central for understanding cytokinesis. The yeast IQGAP (Iqg1p) belongs to the conserved AMR. The F-BAR-domain-containing protein Hof1p is a member of a complex that stimulates cell wall synthesis. We report here on the stepwise formation of a physical connection between both proteins. The C-terminal IQ-repeats of Iqg1p first bind to the essential myosin light chain before both proteins assemble with Hof1p into the Mlc1p-Iqg1p-Hof1p (MIH) bridge. Mutations in Iqg1p that disrupt the MIH complex alter Hof1p targeting to the AMR and impair AMR contraction. Epistasis analyses of two IQG1 alleles that are incompatible with formation of the MIH complex support the existence and functional significance of a large cytokinetic core complex. We propose that the MIH complex acts as hinge between the AMR and the proteins involved in cell wall synthesis and membrane attachment.
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Affiliation(s)
- Chen Tian
- Institute of Molecular Genetics and Cell Biology, Department of Biology, Ulm University, James-Franck-Ring N27, 89081 Ulm, Germany
| | - Yehui Wu
- Institute of Molecular Genetics and Cell Biology, Department of Biology, Ulm University, James-Franck-Ring N27, 89081 Ulm, Germany
| | - Nils Johnsson
- Institute of Molecular Genetics and Cell Biology, Department of Biology, Ulm University, James-Franck-Ring N27, 89081 Ulm, Germany
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42
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Cundell MJ, Price C. The budding yeast amphiphysin complex is required for contractile actin ring (CAR) assembly and post-contraction GEF-independent accumulation of Rho1-GTP. PLoS One 2014; 9:e97663. [PMID: 24874185 PMCID: PMC4038553 DOI: 10.1371/journal.pone.0097663] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 04/22/2014] [Indexed: 12/26/2022] Open
Abstract
The late events of the budding yeast cell division cycle, cytokinesis and cell separation, require the assembly of a contractile actomyosin ring (CAR), primary and secondary septum formation followed by enzymatic degradation of the primary septum. Here we present evidence that demonstrates a role for the budding yeast amphiphysin complex, a heterodimer comprising Rvs167 and Rvs161, in CAR assembly and cell separation. The iqg1-1 allele is synthetically lethal with both rvs167 and rvs161 null mutations. We show that both Iqg1 and the amphiphysin complex are required for CAR assembly in early anaphase but cells are able to complete assembly in late anaphase when these activities are, respectively, either compromised or absent. Amphiphysin dependent CAR assembly is dependent upon the Rvs167 SH3 domain, but this function is insufficient to explain the observed synthetic lethality. Dosage suppression of the iqg1-1 allele demonstrates that endocytosis is required for the default cell separation pathway in the absence of CAR contraction but is unlikely to be required to maintain viability. The amphiphysin complex is required for normal, post-mitotic, localization of Chs3 and the Rho1 GEF, Rom2, which are responsible for secondary septum deposition and the accumulation of GTP bound Rho1 at the bud neck. It is concluded that a failure of polarity establishment in the absence of CAR contraction and amphiphysin function leads to loss of viability as a result of the consequent cell separation defect.
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Affiliation(s)
- Michael John Cundell
- School of Health and Medicine, Division of Biomedical and Life Sciences, Lancaster University, Lancaster, United Kingdom
| | - Clive Price
- School of Health and Medicine, Division of Biomedical and Life Sciences, Lancaster University, Lancaster, United Kingdom
- * E-mail:
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43
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Naylor SG, Morgan DO. Cdk1-dependent phosphorylation of Iqg1 governs actomyosin ring assembly prior to cytokinesis. J Cell Sci 2014; 127:1128-37. [PMID: 24413167 DOI: 10.1242/jcs.144097] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Contraction of the actomyosin ring (AMR) provides the centripetal force that drives cytokinesis. In budding yeast (Saccharomyces cerevisiae), assembly and contraction of the AMR is coordinated with membrane deposition and septum formation at the bud neck. A central player in this process is Iqg1, which promotes recruitment of actin to the myosin ring and links AMR assembly with that of septum-forming components. We observed early actin recruitment in response to inhibition of cyclin-dependent kinase 1 (Cdk1) activity, and we find that the Cdk1-dependent phosphorylation state of Iqg1 is a determining factor in the timing of bud neck localization of both Iqg1 and actin, with both proteins accumulating prematurely in cells expressing nonphosphorylatable Iqg1 mutants. We also identified the primary septum regulator Hof1 as a binding partner of Iqg1, providing a regulatory link between the septation and contractile pathways that cooperate to complete cytokinesis.
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Affiliation(s)
- Stephen G Naylor
- Departments of Physiology and Biochemistry & Biophysics, University of California, San Francisco, CA 94158, USA
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44
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Balasubramanian MK, Tao EY. Timing it right: precise ON/OFF switches for Rho1 and Cdc42 GTPases in cytokinesis. ACTA ACUST UNITED AC 2013; 202:187-9. [PMID: 23878271 PMCID: PMC3718978 DOI: 10.1083/jcb.201306152] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In many eukaryotes, cytokinesis requires an actomyosin contractile ring that is crucial for cell constriction and new membrane organization. Two studies in this issue (Onishi et al. 2013. J. Cell Biol. http://dx.doi.org.10.1083/jcb.201302001 and Atkins et al. 2013. J. Cell Biol. http://dx.doi.org.10.1083/jcb.201301090) establish that precise activation and/or inactivation of Rho1 and Cdc42 GTPases is important for the correct order and successful completion of events downstream of actomyosin ring constriction in budding yeast.
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Affiliation(s)
- Mohan K Balasubramanian
- Temasek Life Sciences Laboratory, 2 Department of Biological Sciences, and 3 Mechanobiology Institute, National University of Singapore, Singapore 117604
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45
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Atkins BD, Yoshida S, Saito K, Wu CF, Lew DJ, Pellman D. Inhibition of Cdc42 during mitotic exit is required for cytokinesis. ACTA ACUST UNITED AC 2013; 202:231-40. [PMID: 23878274 PMCID: PMC3718968 DOI: 10.1083/jcb.201301090] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
A decrease in Cdc42 activation during mitotic exit is necessary to allow localization of key cytokinesis regulators and proper septum formation. The role of Cdc42 and its regulation during cytokinesis is not well understood. Using biochemical and imaging approaches in budding yeast, we demonstrate that Cdc42 activation peaks during the G1/S transition and during anaphase but drops during mitotic exit and cytokinesis. Cdc5/Polo kinase is an important upstream cell cycle regulator that suppresses Cdc42 activity. Failure to down-regulate Cdc42 during mitotic exit impairs the normal localization of key cytokinesis regulators—Iqg1 and Inn1—at the division site, and results in an abnormal septum. The effects of Cdc42 hyperactivation are largely mediated by the Cdc42 effector p21-activated kinase Ste20. Inhibition of Cdc42 and related Rho guanosine triphosphatases may be a general feature of cytokinesis in eukaryotes.
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Affiliation(s)
- Benjamin D Atkins
- Department of Pediatric Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA 02115, USA
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46
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Cassani C, Raspelli E, Santo N, Chiroli E, Lucchini G, Fraschini R. Saccharomyces cerevisiae Dma proteins participate in cytokinesis by controlling two different pathways. Cell Cycle 2013; 12:2794-808. [PMID: 23966170 PMCID: PMC3899193 DOI: 10.4161/cc.25869] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Cytokinesis completion in the budding yeast S. cerevisiae is driven by tightly regulated pathways, leading to actomyosin ring contraction coupled to plasma membrane constriction and to centripetal growth of the primary septum, respectively. These pathways can partially substitute for each other, but their concomitant inactivation leads to cytokinesis block and cell death. Here we show that both the lack of the functionally redundant FHA-RING ubiquitin ligases Dma1 and Dma2 and moderate Dma2 overproduction affect actomyosin ring contraction as well as primary septum deposition, although they do not apparently alter cell cycle progression of otherwise wild-type cells. In addition, overproduction of Dma2 impairs the interaction between Tem1 and Iqg1, which is thought to be required for AMR contraction, and causes asymmetric primary septum deposition as well as mislocalization of the Cyk3-positive regulator of this process. In agreement with these multiple inhibitory effects, a Dma2 excess that does not cause any apparent defect in wild-type cells leads to lethal cytokinesis block in cells lacking the Hof1 protein, which is essential for primary septum formation in the absence of Cyk3. Altogether, these findings suggest that the Dma proteins act as negative regulators of cytokinesis.
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Affiliation(s)
- Corinne Cassani
- Università degli Studi di Milano-Bicocca; Dipartimento di Biotecnologie e Bioscienze; Milano, Italy
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47
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Onishi M, Ko N, Nishihama R, Pringle JR. Distinct roles of Rho1, Cdc42, and Cyk3 in septum formation and abscission during yeast cytokinesis. J Cell Biol 2013; 202:311-29. [PMID: 23878277 PMCID: PMC3718969 DOI: 10.1083/jcb.201302001] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Accepted: 04/11/2013] [Indexed: 01/08/2023] Open
Abstract
In yeast and animal cytokinesis, the small guanosine triphosphatase (GTPase) Rho1/RhoA has an established role in formation of the contractile actomyosin ring, but its role, if any, during cleavage-furrow ingression and abscission is poorly understood. Through genetic screens in yeast, we found that either activation of Rho1 or inactivation of another small GTPase, Cdc42, promoted secondary septum (SS) formation, which appeared to be responsible for abscission. Consistent with this hypothesis, a dominant-negative Rho1 inhibited SS formation but not cleavage-furrow ingression or the concomitant actomyosin ring constriction. Moreover, Rho1 is temporarily inactivated during cleavage-furrow ingression; this inactivation requires the protein Cyk3, which binds Rho1-guanosine diphosphate via its catalytically inactive transglutaminase-like domain. Thus, unlike the active transglutaminases that activate RhoA, the multidomain protein Cyk3 appears to inhibit activation of Rho1 (and thus SS formation), while simultaneously promoting cleavage-furrow ingression through primary septum formation. This work suggests a general role for the catalytically inactive transglutaminases of fungi and animals, some of which have previously been implicated in cytokinesis.
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Affiliation(s)
- Masayuki Onishi
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
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48
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A network of genes connects polyglutamine toxicity to ploidy control in yeast. Nat Commun 2013; 4:1571. [PMID: 23481379 PMCID: PMC3615466 DOI: 10.1038/ncomms2575] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2012] [Accepted: 02/04/2013] [Indexed: 12/17/2022] Open
Abstract
Neurodegeneration is linked to protein aggregation in several human disorders. In Huntington’s disease, the length of a polyglutamine stretch in Huntingtin is correlated to neuronal death. Here we utilize a model based on glutamine stretches of 0, 30 or 56 residues in Saccharomyces cerevisiae to understand how such toxic proteins interfere with cellular physiology. A toxicity-mimicking cytostatic effect is evident from compromised colony formation upon expression of polyglutamines. Interestingly, diploid cells are insensitive to polyglutamines and haploid cells can escape cytostasis by hyperploidization. Using a genome-wide screen for genes required to obtain the cytostatic effect, we identify a network related to the budding process and cellular division. We observe a striking mislocalization of the septins Cdc10 and Shs1 in cells arrested by polyglutamines, suggesting that the septin ring may be a pivotal structure connecting polyglutamine toxicity and ploidy. Expansion of polyglutamines correlates with neuronal death in Huntington’s disease. Here the authors show that, in haploid yeast cells, the toxic effect of polyglutamine expression is associated with the disruption of the septin ring and cells may escape from toxicity by hyperploidization.
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49
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Abstract
Productive cell proliferation involves efficient and accurate splitting of the dividing cell into two separate entities. This orderly process reflects coordination of diverse cytological events by regulatory systems that drive the cell from mitosis into G1. In the budding yeast Saccharomyces cerevisiae, separation of mother and daughter cells involves coordinated actomyosin ring contraction and septum synthesis, followed by septum destruction. These events occur in precise and rapid sequence once chromosomes are segregated and are linked with spindle organization and mitotic progress by intricate cell cycle control machinery. Additionally, critical paarts of the mother/daughter separation process are asymmetric, reflecting a form of fate specification that occurs in every cell division. This chapter describes central events of budding yeast cell separation, as well as the control pathways that integrate them and link them with the cell cycle.
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50
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Oh Y, Schreiter J, Nishihama R, Wloka C, Bi E. Targeting and functional mechanisms of the cytokinesis-related F-BAR protein Hof1 during the cell cycle. Mol Biol Cell 2013; 24:1305-20. [PMID: 23468521 PMCID: PMC3639043 DOI: 10.1091/mbc.e12-11-0804] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Hof1 targets to the division site by interacting with septins and myosin II sequentially during the cell cycle. It plays a role in cytokinesis by coupling actomyosin ring constriction to primary septum formation through interactions with Myo1 and Chs2. F-BAR proteins are membrane‑associated proteins believed to link the plasma membrane to the actin cytoskeleton in cellular processes such as cytokinesis and endocytosis. In the budding yeast Saccharomyces cerevisiae, the F‑BAR protein Hof1 localizes to the division site in a complex pattern during the cell cycle and plays an important role in cytokinesis. However, the mechanisms underlying its localization and function are poorly understood. Here we show that Hof1 contains three distinct targeting domains that contribute to cytokinesis differentially. The N‑terminal half of Hof1 localizes to the bud neck and the sites of polarized growth during the cell cycle. The neck localization is mediated mainly by an interaction between the second coiled‑coil region in the N‑terminus and the septin Cdc10, whereas the localization to the sites of polarized growth is mediated entirely by the F‑BAR domain. In contrast, the C‑terminal half of Hof1 interacts with Myo1, the sole myosin‑II heavy chain in budding yeast, and localizes to the bud neck in a Myo1‑dependent manner from the onset to the completion of cytokinesis. We also show that the SH3 domain in the C‑terminus plays an important role in maintaining the symmetry of Myo1 ring constriction during cytokinesis and that Hof1 interacts with Chs2, a chitin synthase that is required for primary septum formation. Together these data define a mechanism that accounts for the localization of Hof1 during the cell cycle and suggest that Hof1 may function in cytokinesis by coupling actomyosin ring constriction to primary septum formation through interactions with Myo1 and Chs2.
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Affiliation(s)
- Younghoon Oh
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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