1
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Park JS, Turner LA, Gould KL, Willet AH. Characterization of temperature-sensitive alleles of anillin-like Mid1 and polo kinase Plo1 in Schizosaccharomyces pombe. MICROPUBLICATION BIOLOGY 2025; 2025:10.17912/micropub.biology.001552. [PMID: 40161431 PMCID: PMC11953740 DOI: 10.17912/micropub.biology.001552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Figures] [Subscribe] [Scholar Register] [Received: 02/20/2025] [Revised: 03/11/2025] [Accepted: 03/11/2025] [Indexed: 04/02/2025]
Abstract
The Schizosaccharomyces pombe anillin-like Mid1 is important for the correct positioning of the cell division site. A key regulator of Mid1 is the polo kinase Plo1 which is important for several mitotic and cytokinetic events including spindle formation and division site placement. Here, we defined the mutations within a set of temperature-sensitive mid1 and plo1 alleles and compared the growth and morphological defects of the strains. This work expands the repertoire of mid1 and plo1 mutants for studying cytokinesis and highlights the requirement of the Mid1 C2 domain and the Plo1 kinase domain C-terminal lobe as particularly important for cytokinesis.
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Affiliation(s)
- Joshua S. Park
- Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, US
| | - Lesley A. Turner
- Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, US
| | - Kathleen L. Gould
- Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, US
| | - Alaina H. Willet
- Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, US
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2
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Yoshihara S, Nakata T, Kashiwazaki J, Aoyama K, Mabuchi I. In Vitro Formation of Actin Ring in the Fission Yeast Cell Extracts. Cytoskeleton (Hoboken) 2025. [PMID: 39835694 DOI: 10.1002/cm.21997] [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: 09/03/2024] [Revised: 11/18/2024] [Accepted: 01/09/2025] [Indexed: 01/22/2025]
Abstract
Cytokinesis in animal and fungal cells requires the contraction of actomyosin-based contractile rings formed in the division cortex of the cell during late mitosis. However, the detailed mechanism remains incompletely understood. Here, we aim to develop a novel cell-free system by encapsulating cell extracts obtained from fission yeast cells within lipid vesicles, which subsequently leads to the formation of a contractile ring-like structure inside the vesicles. Using this system, we found that an actin ring structure formed in vesicles of a size similar to that of fission yeast cells, with the frequency of ring appearance increasing in the presence of PI(4,5)P2 (PIP2). In contrast, larger vesicles tended to form actin bundles, which were sometimes associated with ring structures or network-like structures. The effects of various inhibitors affecting cytoskeleton formation were investigated, revealing that actin polymerization was essential for the formation of these actin structures. Additionally, the involvement of ATP, the Schizosaccharomyces pombe PLK "Plo1," and the small GTPase Rho was suggested to play a crucial role in this process. Examination of mitotic extracts revealed the formation of actin dot structures in phosphatidylethanolamine vesicles. However, most of these structures disappeared in the presence of PIP2, leading to the formation of actin Rings instead. Using extracts from cells expressing α-actinin Ain1 or myosin-II light chain Rlc1, both fused with fluorescent proteins, we found that these proteins colocalized with actin bundles. In summary, we have developed a new semi-in vitro system to investigate mechanisms such as cell division and cytoskeleton formation.
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Affiliation(s)
- Shogo Yoshihara
- Department of Cell Biology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
- The Center for Brain Integration Research (CBIR), TMDU, Tokyo, Japan
- Department of Life Science, Faculty of Science, Gakushuin University, Mejiro, Tokyo, Japan
| | - Takao Nakata
- Department of Cell Biology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
- The Center for Brain Integration Research (CBIR), TMDU, Tokyo, Japan
| | - Jun Kashiwazaki
- Department of Life Science, Faculty of Science, Gakushuin University, Mejiro, Tokyo, Japan
- Radioisotope Division, Research Facility Center for Science and Technology, Kobe University, Kobe, Hyogo, Japan
- Department of Biology, Graduate School of Science, Kobe University, Kobe, Hyogo, Japan
| | - Kazuhiro Aoyama
- NanoPort Japan, Application Laboratory, Thermo Fisher Scientific, Tokyo, Japan
- Research Center for Ultra-High Voltage Electron Microscopy, Osaka University, Osaka, Japan
| | - Issei Mabuchi
- Department of Life Science, Faculty of Science, Gakushuin University, Mejiro, Tokyo, Japan
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan
- Institute of Human Culture Studies, Otsuma Women's University, Tokyo, Japan
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3
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Singh D, Liu Y, Zhu YH, Zhang S, Naegele S, Wu JQ. Septins function in exocytosis via physical interactions with the exocyst complex in fission yeast cytokinesis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.09.602728. [PMID: 39026698 PMCID: PMC11257574 DOI: 10.1101/2024.07.09.602728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/20/2024]
Abstract
Septins can function as scaffolds for protein recruitment, membrane-bound diffusion barriers, or membrane curvature sensors. Septins are important for cytokinesis, but their exact roles are still obscure. In fission yeast, four septins (Spn1 to Spn4) accumulate at the rim of the division plane as rings. The octameric exocyst complex, which tethers exocytic vesicles to the plasma membrane, exhibits a similar localization and is essential for plasma membrane deposition during cytokinesis. Without septins, the exocyst spreads across the division plane but absent from the rim during septum formation. These results suggest that septins and the exocyst physically interact for proper localization. Indeed, we predicted six pairs of direct interactions between septin and exocyst subunits by AlphaFold2 ColabFold, most of them are confirmed by co-immunoprecipitation and yeast two-hybrid assays. Exocyst mislocalization results in mistargeting of secretory vesicles and their cargos, which leads to cell-separation delay in septin mutants. Our results indicate that septins guide the targeting of exocyst complex on the plasma membrane for vesicle tethering during cytokinesis through direct physical interactions.
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Affiliation(s)
- Davinder Singh
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio, United States
| | - Yajun Liu
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio, United States
| | - Yi-Hua Zhu
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio, United States
| | - Sha Zhang
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio, United States
| | - Shelby Naegele
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio, United States
| | - Jian-Qiu Wu
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio, United States
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, Ohio, United States
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4
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Hall AR, Choi YK, Im W, Vavylonis D. Anillin Related Mid1 as an Adaptive and Multimodal Contractile Ring Anchoring Protein: A Simulation Study. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.27.525865. [PMID: 36747616 PMCID: PMC9900988 DOI: 10.1101/2023.01.27.525865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The organization of the cytokinetic ring at the cell equator of dividing animal and fungi cells depends crucially on the anillin scaffold proteins. In fission yeast, anillin related Mid1 binds to the plasma membrane and helps anchor and organize a medial broad band of cytokinetic nodes, which are the precursors of the contractile ring. Similar to other anillins, Mid1 contains a C terminal globular domain with two potential regions for membrane binding, the Pleckstrin Homology (PH) and C2 domains, and an N terminal intrinsically disordered region that is strongly regulated by phosphorylation. Previous studies have shown that both PH and C2 domains can associate with the membrane, preferring phosphatidylinositol-(4,5)-bisphosphate (PIP 2 ) lipids. However, it is unclear if they can simultaneously bind to the membrane in a way that allows dimerization or oligomerization of Mid1, and if one domain plays a dominant role. To elucidate Mid1's membrane binding mechanism, we used the available structural information of the C terminal region of Mid1 in all-atom molecular dynamics (MD) near a membrane with a lipid composition based on experimental measurements (including PIP 2 lipids). The disordered L3 loop of C2, as well as the PH domain, separately bind the membrane through charged lipid contacts. In simulations with the full C terminal region started away from the membrane, Mid1 binds through the L3 loop and is stabilized in a vertical orientation with the PH domain away from the membrane. However, a configuration with both C2 and PH initially bound to the membrane remains associated with the membrane. These multiple modes of binding may reflect Mid1's multiple interactions with membranes and other node proteins, and ability to sustain mechanical forces.
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5
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Sayyad WA, Pollard TD. The number of cytokinesis nodes in mitotic fission yeast scales with cell size. eLife 2022; 11:76249. [PMID: 36093997 PMCID: PMC9467510 DOI: 10.7554/elife.76249] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 08/18/2022] [Indexed: 11/22/2022] Open
Abstract
Cytokinesis nodes are assemblies of stoichiometric ratios of proteins associated with the plasma membrane, which serve as precursors for the contractile ring during cytokinesis by fission yeast. The total number of nodes is uncertain, because of the limitations of the methods used previously. Here, we used the ~140 nm resolution of Airyscan super-resolution microscopy to measure the fluorescence intensity of small, single cytokinesis nodes marked with Blt1-mEGFP in live fission yeast cells early in mitosis. The ratio of the total Blt1-mEGFP fluorescence in the broad band of cytokinesis nodes to the average fluorescence of a single node gives about 190 single cytokinesis nodes in wild-type fission yeast cells early in mitosis. Most, but not all of these nodes condense into a contractile ring. The number of cytokinesis nodes scales with cell size in four strains tested, although large diameter rga4Δ mutant cells form somewhat fewer cytokinesis nodes than expected from the overall trend. The Pom1 kinase restricts cytokinesis nodes from the ends of cells, but the surface density of Pom1 on the plasma membrane around the equators of cells is similar with a wide range of node numbers, so Pom1 does not control cytokinesis node number. However, when the concentrations of either kinase Pom1 or kinase Cdr2 were varied with the nmt1 promoter, the numbers of cytokinesis nodes increased above a baseline of about ~190 with the total cellular concentration of either kinase.
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Affiliation(s)
- Wasim A Sayyad
- Department of Molecular Cellular and Developmental Biology,Yale University, New Haven, United States
| | - Thomas D Pollard
- Department of Molecular Cellular and Developmental Biology,Yale University, New Haven, United States.,Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, United States.,Department of Cell Biology,Yale University, New Haven, United States
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6
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Bellingham-Johnstun K, Anders EC, Ravi J, Bruinsma C, Laplante C. Molecular organization of cytokinesis node predicts the constriction rate of the contractile ring. J Cell Biol 2021; 220:211718. [PMID: 33496728 PMCID: PMC7844425 DOI: 10.1083/jcb.202008032] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 11/23/2020] [Accepted: 12/22/2020] [Indexed: 01/21/2023] Open
Abstract
The molecular organization of cytokinesis proteins governs contractile ring function. We used single molecule localization microscopy in live cells to elucidate the molecular organization of cytokinesis proteins and relate it to the constriction rate of the contractile ring. Wild-type fission yeast cells assemble contractile rings by the coalescence of cortical proteins complexes called nodes whereas cells without Anillin/Mid1p (Δmid1) lack visible nodes yet assemble contractile rings competent for constriction from the looping of strands. We leveraged the Δmid1 contractile ring assembly mechanism to determine how two distinct molecular organizations, nodes versus strands, can yield functional contractile rings. Contrary to previous interpretations, nodes assemble in Δmid1 cells. Our results suggest that Myo2p heads condense upon interaction with actin filaments and an excess number of Myo2p heads bound to actin filaments hinders constriction thus reducing the constriction rate. Our work establishes a predictive correlation between the molecular organization of nodes and the behavior of the contractile ring.
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Affiliation(s)
- Kimberly Bellingham-Johnstun
- Molecular Biomedical Sciences Department, College of Veterinary Medicine, North Carolina State University, Raleigh, NC
| | - Erica Casey Anders
- Molecular Biomedical Sciences Department, College of Veterinary Medicine, North Carolina State University, Raleigh, NC
| | - John Ravi
- Molecular Biomedical Sciences Department, College of Veterinary Medicine, North Carolina State University, Raleigh, NC
| | - Christina Bruinsma
- Molecular Biomedical Sciences Department, College of Veterinary Medicine, North Carolina State University, Raleigh, NC
| | - Caroline Laplante
- Molecular Biomedical Sciences Department, College of Veterinary Medicine, North Carolina State University, Raleigh, NC
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7
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Gerien KS, Zhang S, Russell AC, Zhu YH, Purde V, Wu JQ. Roles of Mso1 and the SM protein Sec1 in efficient vesicle fusion during fission yeast cytokinesis. Mol Biol Cell 2020; 31:1570-1583. [PMID: 32432970 PMCID: PMC7521796 DOI: 10.1091/mbc.e20-01-0067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Membrane trafficking during cytokinesis is essential for the delivery of membrane lipids and cargoes to the division site. However, the molecular mechanisms are still incompletely understood. In this study, we demonstrate the importance of uncharacterized fission yeast proteins Mso1 and Sec1 in membrane trafficking during cytokinesis. Fission yeast Mso1 shares homology with budding yeast Mso1 and human Mint1, proteins that interact with Sec1/Munc18 family proteins during vesicle fusion. Sec1/Munc18 proteins and their interactors are important regulators of SNARE complex formation during vesicle fusion. The roles of these proteins in vesicle trafficking during cytokinesis have been barely studied. Here, we show that fission yeast Mso1 is also a Sec1-binding protein and Mso1 and Sec1 localize to the division site interdependently during cytokinesis. The loss of Sec1 localization in mso1Δ cells results in a decrease in vesicle fusion and cytokinesis defects such as slow ring constriction, defective ring disassembly, and delayed plasma membrane closure. We also find that Mso1 and Sec1 may have functions independent of the exocyst tethering complex on the plasma membrane at the division site. Together, Mso1 and Sec1 play essential roles in regulating vesicle fusion and cargo delivery at the division site during cytokinesis.
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Affiliation(s)
- Kenneth S Gerien
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210.,Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210
| | - Sha Zhang
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210
| | - Alexandra C Russell
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210
| | - Yi-Hua Zhu
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210
| | - Vedud Purde
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210.,Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210
| | - Jian-Qiu Wu
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210.,Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH 43210
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8
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Xu T, Langouras C, Koudehi MA, Vos BE, Wang N, Koenderink GH, Huang X, Vavylonis D. Automated Tracking of Biopolymer Growth and Network Deformation with TSOAX. Sci Rep 2019; 9:1717. [PMID: 30737416 PMCID: PMC6368602 DOI: 10.1038/s41598-018-37182-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 12/03/2018] [Indexed: 01/03/2023] Open
Abstract
Studies of how individual semi-flexible biopolymers and their network assemblies change over time reveal dynamical and mechanical properties important to the understanding of their function in tissues and living cells. Automatic tracking of biopolymer networks from fluorescence microscopy time-lapse sequences facilitates such quantitative studies. We present an open source software tool that combines a global and local correspondence algorithm to track biopolymer networks in 2D and 3D, using stretching open active contours. We demonstrate its application in fully automated tracking of elongating and intersecting actin filaments, detection of loop formation and constriction of tilted contractile rings in live cells, and tracking of network deformation under shear deformation.
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Affiliation(s)
- Ting Xu
- Department of Computer Science and Engineering, Lehigh University, Bethlehem, PA, 18015, USA
| | | | | | - Bart E Vos
- AMOLF, Living Matter Department, 1098 XG, Amsterdam, The Netherlands
| | - Ning Wang
- Department of Molecular Genetics, The Ohio State University, Columbus, OH, 43210, USA
- Howard Hughes Medical Institute and Department of Cell Biology, Harvard Medical School, Boston, MA, 02115, USA
| | | | - Xiaolei Huang
- Department of Computer Science and Engineering, Lehigh University, Bethlehem, PA, 18015, USA.
- College of Information Sciences and Technology, Penn State University, University Park, PA, 16802, USA.
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9
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Molecular mechanisms of contractile-ring constriction and membrane trafficking in cytokinesis. Biophys Rev 2018; 10:1649-1666. [PMID: 30448943 DOI: 10.1007/s12551-018-0479-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 11/06/2018] [Indexed: 12/14/2022] Open
Abstract
In this review, we discuss the molecular mechanisms of cytokinesis from plants to humans, with a focus on contribution of membrane trafficking to cytokinesis. Selection of the division site in fungi, metazoans, and plants is reviewed, as well as the assembly and constriction of a contractile ring in fungi and metazoans. We also provide an introduction to exocytosis and endocytosis, and discuss how they contribute to successful cytokinesis in eukaryotic cells. The conservation in the coordination of membrane deposition and cytoskeleton during cytokinesis in fungi, metazoans, and plants is highlighted.
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10
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Zhu YH, Hyun J, Pan YZ, Hopper JE, Rizo J, Wu JQ. Roles of the fission yeast UNC-13/Munc13 protein Ync13 in late stages of cytokinesis. Mol Biol Cell 2018; 29:2259-2279. [PMID: 30044717 PMCID: PMC6249806 DOI: 10.1091/mbc.e18-04-0225] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Cytokinesis is a complicated yet conserved step of the cell-division cycle that requires the coordination of multiple proteins and cellular processes. Here we describe a previously uncharacterized protein, Ync13, and its roles during fission yeast cytokinesis. Ync13 is a member of the UNC-13/Munc13 protein family, whose animal homologues are essential priming factors for soluble N-ethylmaleimide-sensitive factor attachment protein receptor complex assembly during exocytosis in various cell types, but no roles in cytokinesis have been reported. We find that Ync13 binds to lipids in vitro and dynamically localizes to the plasma membrane at cell tips during interphase and at the division site during cytokinesis. Deletion of Ync13 leads to defective septation and exocytosis, uneven distribution of cell-wall enzymes and components of cell-wall integrity pathway along the division site and massive cell lysis during cell separation. Interestingly, loss of Ync13 compromises endocytic site selection at the division plane. Collectively, we find that Ync13 has a novel function as an UNC-13/Munc13 protein in coordinating exocytosis, endocytosis, and cell-wall integrity during fission yeast cytokinesis.
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Affiliation(s)
- Yi-Hua Zhu
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210
| | - Joanne Hyun
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210
| | - Yun-Zu Pan
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX 75390.,Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390.,Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - James E Hopper
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210.,Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210
| | - Josep Rizo
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX 75390.,Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390.,Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Jian-Qiu Wu
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210.,Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH 43210
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11
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Akamatsu M, Lin Y, Bewersdorf J, Pollard TD. Analysis of interphase node proteins in fission yeast by quantitative and superresolution fluorescence microscopy. Mol Biol Cell 2017; 28:3203-3214. [PMID: 28539404 PMCID: PMC5687023 DOI: 10.1091/mbc.e16-07-0522] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 04/14/2017] [Accepted: 05/15/2017] [Indexed: 02/06/2023] Open
Abstract
We used quantitative confocal microscopy and FPALM superresolution microscopy of live fission yeast to investigate the structures and assembly of two types of interphase nodes-multiprotein complexes associated with the plasma membrane that merge together and mature into the precursors of the cytokinetic contractile ring. During the long G2 phase of the cell cycle, seven different interphase node proteins maintain constant concentrations as they accumulate in proportion to cell volume. During mitosis, the total numbers of type 1 node proteins (cell cycle kinases Cdr1p, Cdr2p, Wee1p, and anillin Mid1p) are constant even when the nodes disassemble. Quantitative measurements provide strong evidence that both types of nodes have defined sizes and numbers of constituent proteins, as observed for cytokinesis nodes. Type 1 nodes assemble in two phases-a burst at the end of mitosis, followed by steady increase during interphase to double the initial number. Type 2 nodes containing Blt1p, Rho-GEF Gef2p, and kinesin Klp8p remain intact throughout the cell cycle and are constituents of the contractile ring. They are released from the contractile ring as it disassembles and then associate with type 1 nodes around the equator of the cell during interphase.
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Affiliation(s)
- Matthew Akamatsu
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520-8103.,Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520-8103.,Integrated Graduate Program in Physical and Engineering Biology, Yale University, New Haven, CT 06520-8103
| | - Yu Lin
- Integrated Graduate Program in Physical and Engineering Biology, Yale University, New Haven, CT 06520-8103.,Department of Cell Biology, Yale University, New Haven, CT 06520-8103.,Department of Biomedical Engineering, Yale University, New Haven, CT 06520-8103
| | - Joerg Bewersdorf
- Integrated Graduate Program in Physical and Engineering Biology, Yale University, New Haven, CT 06520-8103.,Department of Biomedical Engineering, Yale University, New Haven, CT 06520-8103
| | - Thomas D Pollard
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520-8103 .,Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520-8103.,Department of Cell Biology, Yale University, New Haven, CT 06520-8103
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12
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Abstract
SUMMARYCell division-cytokinesis-involves large-scale rearrangements of the entire cell. Primarily driven by cytoskeletal proteins, cytokinesis also depends on topological rearrangements of the plasma membrane, which are coordinated with nuclear division in both space and time. Despite the fundamental nature of the process, different types of eukaryotic cells show variations in both the structural mechanisms of cytokinesis and the regulatory controls. In animal cells and fungi, a contractile actomyosin-based structure plays a central, albeit flexible, role. Here, the underlying molecular mechanisms are summarized and integrated and common themes are highlighted.
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Affiliation(s)
- Michael Glotzer
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, Illinois 60637
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13
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Rincon SA, Estravis M, Dingli F, Loew D, Tran PT, Paoletti A. SIN-Dependent Dissociation of the SAD Kinase Cdr2 from the Cell Cortex Resets the Division Plane. Curr Biol 2017; 27:534-542. [PMID: 28162898 DOI: 10.1016/j.cub.2016.12.050] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 11/28/2016] [Accepted: 12/22/2016] [Indexed: 11/16/2022]
Abstract
Proper division plane positioning is crucial for faithful chromosome segregation but also influences cell size, position, or fate [1]. In fission yeast, medial division is controlled through negative signaling by the cell tips during interphase and positive signaling by the centrally placed nucleus at mitotic entry [2-4]: the cell geometry network (CGN), controlled by the inhibitory cortical gradient of the DYRK kinase Pom1 emanating from the cell tips, first promotes the medial localization of cytokinetic ring precursors organized by the SAD kinase Cdr2 to pre-define the division plane [5-8]; then, massive nuclear export of the anillin-like protein Mid1 at mitosis entry confirms or readjusts the division plane according to nuclear position and triggers the assembly of a medial contractile ring [5, 9-11]. Strikingly, the Hippo-like septation initiation network (SIN) induces Cdr2 dissociation from cytokinetic precursors at this stage [12-14]. We show here that SIN-dependent phosphorylation of Cdr2 promotes its interaction with the 14-3-3 protein Rad24 that sequesters it in the cytoplasm during cell division. If this interaction is compromised, cytokinetic precursors are asymmetrically distributed in the cortex of newborn cells, leading to asymmetrical division if nuclear signaling is abolished. We conclude that, through this new function, the SIN resets the division plane in newborn cells to ensure medial division.
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Affiliation(s)
- Sergio A Rincon
- Institut Curie, PSL Research University, CNRS, UMR 144, 75005 Paris, France.
| | - Miguel Estravis
- Institute of Genetics and Development of Rennes, CNRS, UMR 6290, 35043 Rennes Cedex, France
| | - Florent Dingli
- Laboratoire de Spectrométrie de Masse Protéomique, Institut Curie, PSL Research University, 75005 Paris, France
| | - Damarys Loew
- Laboratoire de Spectrométrie de Masse Protéomique, Institut Curie, PSL Research University, 75005 Paris, France
| | - Phong T Tran
- Institut Curie, PSL Research University, CNRS, UMR 144, 75005 Paris, France; Cell and Developmental Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Anne Paoletti
- Institut Curie, PSL Research University, CNRS, UMR 144, 75005 Paris, France.
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14
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Davidson R, Pontasch JA, Wu JQ. Sbg1 Is a Novel Regulator for the Localization of the β-Glucan Synthase Bgs1 in Fission Yeast. PLoS One 2016; 11:e0167043. [PMID: 27898700 PMCID: PMC5127554 DOI: 10.1371/journal.pone.0167043] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2016] [Accepted: 11/08/2016] [Indexed: 02/03/2023] Open
Abstract
Glucan synthases synthesize glucans, complex polysaccharides that are the major components in fungal cell walls and division septa. Studying regulation of glucan synthases is important as they are essential for fungal cell survival and thus popular targets for anti-fungal drugs. Linear 1,3-β-glucan is the main component of primary septum and is synthesized by the conserved β-glucan synthase Bgs1 in fission yeast cytokinesis. It is known that Rho1 GTPase regulates Bgs1 catalytic activity and the F-BAR protein Cdc15 plays a role in Bgs1 delivery to the plasma membrane. Here we characterize a novel protein Sbg1 that is present in a complex with Bgs1 and regulates its protein levels and localization. Sbg1 is essential for contractile-ring constriction and septum formation during cytokinesis. Sbg1 and Bgs1 physically interact and are interdependent for localization to the plasma membrane. Bgs1 is less stable and/or mis-targeted to vacuoles in sbg1 mutants. Moreover, Sbg1 plays an earlier and more important role in Bgs1 trafficking and localization than Cdc15. Together, our data reveal a new mode of regulation for the essential β-glucan synthase Bgs1 by the novel protein Sbg1.
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Affiliation(s)
- Reshma Davidson
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio, United States of America
| | - Josef A. Pontasch
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio, United States of America
| | - Jian-Qiu Wu
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio, United States of America
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, Ohio, United States of America
- * E-mail:
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15
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Liu Y, Lee IJ, Sun M, Lower CA, Runge KW, Ma J, Wu JQ. Roles of the novel coiled-coil protein Rng10 in septum formation during fission yeast cytokinesis. Mol Biol Cell 2016; 27:2528-41. [PMID: 27385337 PMCID: PMC4985255 DOI: 10.1091/mbc.e16-03-0156] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 06/21/2016] [Indexed: 12/31/2022] Open
Abstract
The regulation of Rho-GAP localization is not well understood. A novel coiled-coil protein Rng10 is characterized that localizes the Rho-GAP Rga7 in fission yeast. Rng10 and Rga7 physically interact and work together to regulate the accumulation and dynamics of glucan synthases for successful septum formation during cytokinesis. Rho GAPs are important regulators of Rho GTPases, which are involved in various steps of cytokinesis and other processes. However, regulation of Rho-GAP cellular localization and function is not fully understood. Here we report the characterization of a novel coiled-coil protein Rng10 and its relationship with the Rho-GAP Rga7 in fission yeast. Both rng10Δ and rga7Δ result in defective septum and cell lysis during cytokinesis. Rng10 and Rga7 colocalize on the plasma membrane at the cell tips during interphase and at the division site during cell division. Rng10 physically interacts with Rga7 in affinity purification and coimmunoprecipitation. Of interest, Rga7 localization is nearly abolished without Rng10. Moreover, Rng10 and Rga7 work together to regulate the accumulation and dynamics of glucan synthases for successful septum formation in cytokinesis. Our results show that cellular localization and function of the Rho-GAP Rga7 are regulated by a novel protein, Rng10, during cytokinesis in fission yeast.
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Affiliation(s)
- Yajun Liu
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210
| | - I-Ju Lee
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210
| | - Mingzhai Sun
- Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210
| | - Casey A Lower
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210
| | - Kurt W Runge
- Department of Molecular Genetics, Cleveland Clinic Lerner College of Medicine, Cleveland, OH 44195
| | - Jianjie Ma
- Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210
| | - Jian-Qiu Wu
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210 Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH 43210
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16
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Yasuda T, Takaine M, Numata O, Nakano K. Anillin-related protein Mid1 regulates timely formation of the contractile ring in the fission yeastSchizosaccharomyces japonicus. Genes Cells 2016; 21:594-607. [DOI: 10.1111/gtc.12368] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2015] [Accepted: 03/03/2016] [Indexed: 11/29/2022]
Affiliation(s)
- Tsuyoshi Yasuda
- Department of Biological Sciences; Graduate School of Life and Environmental Sciences; University of Tsukuba; Tsukuba Ibaraki 305-8572 Japan
| | - Masak Takaine
- Department of Biological Sciences; Graduate School of Life and Environmental Sciences; University of Tsukuba; Tsukuba Ibaraki 305-8572 Japan
| | - Osamu Numata
- Department of Biological Sciences; Graduate School of Life and Environmental Sciences; University of Tsukuba; Tsukuba Ibaraki 305-8572 Japan
| | - Kentaro Nakano
- Department of Biological Sciences; Graduate School of Life and Environmental Sciences; University of Tsukuba; Tsukuba Ibaraki 305-8572 Japan
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17
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Rincon SA, Paoletti A. Molecular control of fission yeast cytokinesis. Semin Cell Dev Biol 2016; 53:28-38. [PMID: 26806637 DOI: 10.1016/j.semcdb.2016.01.007] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 01/06/2016] [Indexed: 12/29/2022]
Abstract
Cytokinesis gives rise to two independent daughter cells at the end of the cell division cycle. The fission yeast Schizosaccharomyces pombe has emerged as one of the most powerful systems to understand how cytokinesis is controlled molecularly. Like in most eukaryotes, fission yeast cytokinesis depends on an acto-myosin based contractile ring that assembles at the division site under the control of spatial cues that integrate information on cell geometry and the position of the mitotic apparatus. Cytokinetic events are also tightly coordinated with nuclear division by the cell cycle machinery. These spatial and temporal regulations ensure an equal cleavage of the cytoplasm and an accurate segregation of the genetic material in daughter cells. Although this model system has specificities, the basic mechanisms of contractile ring assembly and function deciphered in fission yeast are highly valuable to understand how cytokinesis is controlled in other organisms that rely on a contractile ring for cell division.
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Affiliation(s)
- Sergio A Rincon
- Institut Curie, Centre de Recherche, PSL Research University, F-75248 Paris, France; CNRS UMR144, F-75248 Paris, France
| | - Anne Paoletti
- Institut Curie, Centre de Recherche, PSL Research University, F-75248 Paris, France; CNRS UMR144, F-75248 Paris, France.
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18
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Comparative biology of cell division in the fission yeast clade. Curr Opin Microbiol 2015; 28:18-25. [PMID: 26263485 DOI: 10.1016/j.mib.2015.07.011] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Revised: 07/07/2015] [Accepted: 07/17/2015] [Indexed: 11/21/2022]
Abstract
Cytokinesis must be regulated in time and space in order to preserve genome integrity during cell proliferation and to allow daughter cells to adopt distinct fates and geometries during differentiation. The fission yeast Schizosaccharomyces pombe has been a popular model organism for understanding spatiotemporal regulation of cytokinesis in a symmetrically dividing cell. Recent work on another member of the same genus, Schisozaccharomyces japonicus, suggests that S. pombe may have evolved an unusual division site placement mechanism based on a recently duplicated anillin paralog. Here we discuss an extraordinary evolutionary plasticity of cytokinesis within the fission yeast clade and argue that the comparative cell biology approach may provide functional insights beyond those afforded by scrutinizing individual model species.
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19
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Laplante C, Berro J, Karatekin E, Hernandez-Leyva A, Lee R, Pollard TD. Three myosins contribute uniquely to the assembly and constriction of the fission yeast cytokinetic contractile ring. Curr Biol 2015; 25:1955-65. [PMID: 26144970 DOI: 10.1016/j.cub.2015.06.018] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2014] [Revised: 05/16/2015] [Accepted: 06/05/2015] [Indexed: 11/30/2022]
Abstract
Cytokinesis in fission yeast cells depends on conventional myosin-II (Myo2) to assemble and constrict a contractile ring of actin filaments. Less is known about the functions of an unconventional myosin-II (Myp2) and a myosin-V (Myo51) that are also present in the contractile ring. Myo2 appears in cytokinetic nodes around the equator 10 min before spindle pole body separation (cell-cycle time, -10 min) independent of actin filaments, followed by Myo51 at time zero and Myp2 at time +20 min, both located between nodes and dependent on actin filaments. We investigated the contributions of these three myosins to cytokinesis using a severely disabled mutation of the essential myosin-II heavy-chain gene (myo2-E1) and deletion mutations of the other myosin heavy-chain genes. Cells with only Myo2 assemble contractile rings normally. Cells with either Myp2 or Myo51 alone can assemble nodes and actin filaments into contractile rings but complete assembly later than normal. Both Myp2 and Myo2 contribute to constriction of fully assembled rings at rates 55% that of normal in cells relying on Myp2 alone and 25% that of normal in cells with Myo2 alone. Myo51 alone cannot constrict rings but increases the constriction rate by Myo2 in Δmyp2 cells or Myp2 in myo2-E1 cells. Three myosins function in a hierarchal, complementary manner to accomplish cytokinesis, with Myo2 and Myo51 taking the lead during contractile ring assembly and Myp2 making the greatest contribution to constriction.
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Affiliation(s)
- Caroline Laplante
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06520, USA
| | - Julien Berro
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA; Nanobiology Institute, Yale University, West Haven, CT 06516, USA
| | - Erdem Karatekin
- Nanobiology Institute, Yale University, West Haven, CT 06516, USA; Department of Cellular and Molecular Physiology, Yale University, New Haven, CT 06520, USA; Institut des Sciences Biologiques, Centre National de la Recherche Scientifique (CNRS), Délégation Paris Michel-Ange, 3 rue Michel-Ange, 75794 Paris Cedex 16, France
| | - Ariel Hernandez-Leyva
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06520, USA
| | - Rachel Lee
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06520, USA
| | - Thomas D Pollard
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06520, USA; Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA; Department of Cell Biology, Yale University, New Haven, CT 06520, USA.
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20
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Sun L, Guan R, Lee IJ, Liu Y, Chen M, Wang J, Wu JQ, Chen Z. Mechanistic insights into the anchorage of the contractile ring by anillin and Mid1. Dev Cell 2015; 33:413-26. [PMID: 25959226 DOI: 10.1016/j.devcel.2015.03.003] [Citation(s) in RCA: 91] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Revised: 01/22/2015] [Accepted: 03/02/2015] [Indexed: 11/17/2022]
Abstract
Anillins and Mid1 are scaffold proteins that play key roles in anchorage of the contractile ring at the cell equator during cytokinesis in animals and fungi, respectively. Here, we report crystal structures and functional analysis of human anillin and S. pombe Mid1. The combined data show anillin contains a cryptic C2 domain and a Rho-binding domain. Together with the tethering PH domain, three membrane-associating elements synergistically bind to RhoA and phospholipids to anchor anillin at the cleavage furrow. Surprisingly, Mid1 also binds to the membrane through a cryptic C2 domain. Dimerization of Mid1 leads to high affinity and preference for PI(4,5)P2, which stably anchors Mid1 at the division plane, bypassing the requirement for Rho GTPase. These findings uncover the unexpected general machinery and the divergent regulatory logics for the anchorage of the contractile ring through the anillin/Mid1 family proteins from yeast to humans.
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Affiliation(s)
- Lingfei Sun
- MOE Key Laboratory of Protein Science, Tsinghua University, Beijing 100084, China; School of Life Science, Tsinghua University, Beijing 100084, China
| | - Ruifang Guan
- MOE Key Laboratory of Protein Science, Tsinghua University, Beijing 100084, China; School of Life Science, Tsinghua University, Beijing 100084, China
| | - I-Ju Lee
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210, USA
| | - Yajun Liu
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210, USA
| | - Mengran Chen
- MOE Key Laboratory of Protein Science, Tsinghua University, Beijing 100084, China; School of Life Science, Tsinghua University, Beijing 100084, China
| | - Jiawei Wang
- School of Life Science, Tsinghua University, Beijing 100084, China; State Key Laboratory of Bio-membrane and Membrane Biotechnology, Tsinghua University, Beijing 100084, China
| | - Jian-Qiu Wu
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210, USA
| | - Zhucheng Chen
- MOE Key Laboratory of Protein Science, Tsinghua University, Beijing 100084, China; School of Life Science, Tsinghua University, Beijing 100084, China.
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21
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Davidson R, Laporte D, Wu JQ. Regulation of Rho-GEF Rgf3 by the arrestin Art1 in fission yeast cytokinesis. Mol Biol Cell 2014; 26:453-66. [PMID: 25473118 PMCID: PMC4310737 DOI: 10.1091/mbc.e14-07-1252] [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] [Indexed: 01/14/2023] Open
Abstract
The arrestin Art1 and the Rho1 guanine nucleotide exchange factor Rgf3 are interdependent for their localizations to the division site during fission yeast cytokinesis. Art1 physically interacts with Rgf3 to modulate active Rho1 GTPase levels for successful septal formation. Rho GTPases, activated by guanine nucleotide exchange factors (GEFs), are essential regulators of polarized cell growth, cytokinesis, and many other cellular processes. However, the regulation of Rho-GEFs themselves is not well understood. Rgf3 is an essential GEF for Rho1 GTPase in fission yeast. We show that Rgf3 protein levels and localization are regulated by arrestin-related protein Art1. art1∆ cells lyse during cell separation with a thinner and defective septum. As does Rgf3, Art1 concentrates to the contractile ring starting at early anaphase and spreads to the septum during and after ring constriction. Art1 localization depends on its C-terminus, and Art1 is important for maintaining Rgf3 protein levels. Biochemical experiments reveal that the Rgf3 C-terminus binds to Art1. Using an Rgf3 conditional mutant and mislocalization experiments, we found that Art1 and Rgf3 are interdependent for localization to the division site. As expected, active Rho1 levels at the division site are reduced in art1∆ and rgf3 mutant cells. Taken together, these data reveal that the arrestin family protein Art1 regulates the protein levels and localization of the Rho-GEF Rgf3, which in turn modulates active Rho1 levels during fission yeast cytokinesis.
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Affiliation(s)
- Reshma Davidson
- Graduate Program of Molecular, Cellular, and Developmental Biology, The Ohio State University, Columbus, OH 43210 Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210
| | - Damien Laporte
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210
| | - Jian-Qiu Wu
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210 Department of Molecular and Cellular Biochemistry, The Ohio State University, Columbus, OH 43210
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22
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Wang N, Wang M, Zhu YH, Grosel TW, Sun D, Kudryashov DS, Wu JQ. The Rho-GEF Gef3 interacts with the septin complex and activates the GTPase Rho4 during fission yeast cytokinesis. Mol Biol Cell 2014; 26:238-55. [PMID: 25411334 PMCID: PMC4294672 DOI: 10.1091/mbc.e14-07-1196] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Rho GTPases, activated by Rho guanine nucleotide exchange factors (GEFs), are conserved molecular switches for signal transductions that regulate diverse cellular processes, including cell polarization and cytokinesis. The fission yeast Schizosaccharomyces pombe has six Rho GTPases (Cdc42 and Rho1-Rho5) and seven Rho GEFs (Scd1, Rgf1-Rgf3, and Gef1-Gef3). The GEFs for Rho2-Rho5 have not been unequivocally assigned. In particular, Gef3, the smallest Rho GEF, was barely studied. Here we show that Gef3 colocalizes with septins at the cell equator. Gef3 physically interacts with septins and anillin Mid2 and depends on them to localize. Gef3 coprecipitates with GDP-bound Rho4 in vitro and accelerates nucleotide exchange of Rho4, suggesting that Gef3 is a GEF for Rho4. Consistently, Gef3 and Rho4 are in the same genetic pathways to regulate septum formation and/or cell separation. In gef3∆ cells, the localizations of two potential Rho4 effectors--glucanases Eng1 and Agn1--are abnormal, and active Rho4 level is reduced, indicating that Gef3 is involved in Rho4 activation in vivo. Moreover, overexpression of active Rho4 or Eng1 rescues the septation defects of mutants containing gef3∆. Together our data support that Gef3 interacts with the septin complex and activates Rho4 GTPase as a Rho GEF for septation in fission yeast.
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Affiliation(s)
| | - Mo Wang
- Department of Molecular Genetics
| | | | | | | | | | - Jian-Qiu Wu
- Department of Molecular Genetics Department of Molecular and Cellular Biochemistry, The Ohio State University, Columbus, OH 43210
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23
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Arasada R, Pollard TD. Contractile ring stability in S. pombe depends on F-BAR protein Cdc15p and Bgs1p transport from the Golgi complex. Cell Rep 2014; 8:1533-44. [PMID: 25159149 DOI: 10.1016/j.celrep.2014.07.048] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Revised: 05/22/2014] [Accepted: 07/25/2014] [Indexed: 11/17/2022] Open
Abstract
Cdc15p is known to contribute to cytokinesis in fission yeast; however, the protein is not required to assemble the contractile ring of actin and myosin, but it helps to anchor the ring to the plasma membrane. Cdc15p has a lipid-binding F-BAR domain, suggesting that it provides a physical link between the plasma membrane and contractile ring proteins. However, we find that a more important function of Cdc15p during cytokinesis is to help deliver a transmembrane enzyme, Bgs1p (also called Cps1p), from the Golgi apparatus to the plasma membrane, where it appears to anchor the contractile ring. Bgs1p synthesizes the cell wall in the cleavage furrow, but its enzyme activity is not required to anchor the contractile ring. We estimate that ∼ 2,000 Bgs1p molecules are required to anchor the ring. Without Bgs1p anchors, contractile rings slide along the plasma membrane, a phenomenon that depends on an unconventional type II myosin called Myp2p.
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Affiliation(s)
- Rajesh Arasada
- Department of Molecular Cellular and Developmental Biology, Yale University, P.O. Box 208103, New Haven, CT 06520-8103 USA
| | - Thomas D Pollard
- Department of Molecular Cellular and Developmental Biology, Yale University, P.O. Box 208103, New Haven, CT 06520-8103 USA; Department of Molecular Biophysics and Biochemistry, Yale University, P.O. Box 208103, New Haven, CT 06520-8103 USA; Department of Cell Biology, Yale University, P.O. Box 208103, New Haven, CT 06520-8103 USA.
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24
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Lee IJ, Wang N, Hu W, Schott K, Bähler J, Giddings TH, Pringle JR, Du LL, Wu JQ. Regulation of spindle pole body assembly and cytokinesis by the centrin-binding protein Sfi1 in fission yeast. Mol Biol Cell 2014; 25:2735-49. [PMID: 25031431 PMCID: PMC4161509 DOI: 10.1091/mbc.e13-11-0699] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
A previous model suggested doubling of Sfi1 as the first step of SPB assembly. Here it is shown that Sfi1 is gradually recruited to SPBs throughout the cell cycle. Conserved tryptophans in Sfi1 are required for its equal partitioning during mitosis, and unequal partitioning of Sfi1 underlies SPB assembly and mitotic defects in the next cell cycle. Centrosomes play critical roles in the cell division cycle and ciliogenesis. Sfi1 is a centrin-binding protein conserved from yeast to humans. Budding yeast Sfi1 is essential for the initiation of spindle pole body (SPB; yeast centrosome) duplication. However, the recruitment and partitioning of Sfi1 to centrosomal structures have never been fully investigated in any organism, and the presumed importance of the conserved tryptophans in the internal repeats of Sfi1 remains untested. Here we report that in fission yeast, instead of doubling abruptly at the initiation of SPB duplication and remaining at a constant level thereafter, Sfi1 is gradually recruited to SPBs throughout the cell cycle. Like an sfi1Δ mutant, a Trp-to-Arg mutant (sfi1-M46) forms monopolar spindles and exhibits mitosis and cytokinesis defects. Sfi1-M46 protein associates preferentially with one of the two daughter SPBs during mitosis, resulting in a failure of new SPB assembly in the SPB receiving insufficient Sfi1. Although all five conserved tryptophans tested are involved in Sfi1 partitioning, the importance of the individual repeats in Sfi1 differs. In summary, our results reveal a link between the conserved tryptophans and Sfi1 partitioning and suggest a revision of the model for SPB assembly.
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Affiliation(s)
- I-Ju Lee
- Graduate Program of Molecular, Cellular, and Developmental Biology, The Ohio State University, Columbus, OH 43210 Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210
| | - Ning Wang
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210
| | - Wen Hu
- National Institute of Biological Sciences, Beijing 102206, China
| | - Kersey Schott
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210
| | - Jürg Bähler
- Department of Genetics, Evolution and Environment, University College London, London WC1E 6BT, United Kingdom
| | - Thomas H Giddings
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado-Boulder, Boulder, CO 80309
| | - John R Pringle
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305
| | - Li-Lin Du
- National Institute of Biological Sciences, Beijing 102206, China
| | - Jian-Qiu Wu
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210 Department of Molecular and Cellular Biochemistry, The Ohio State University, Columbus, OH 43210
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25
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Wang N, Lo Presti L, Zhu YH, Kang M, Wu Z, Martin SG, Wu JQ. The novel proteins Rng8 and Rng9 regulate the myosin-V Myo51 during fission yeast cytokinesis. ACTA ACUST UNITED AC 2014; 205:357-75. [PMID: 24798735 PMCID: PMC4018781 DOI: 10.1083/jcb.201308146] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The myosin-V family of molecular motors is known to be under sophisticated regulation, but our knowledge of the roles and regulation of myosin-Vs in cytokinesis is limited. Here, we report that the myosin-V Myo51 affects contractile ring assembly and stability during fission yeast cytokinesis, and is regulated by two novel coiled-coil proteins, Rng8 and Rng9. Both rng8Δ and rng9Δ cells display similar defects as myo51Δ in cytokinesis. Rng8 and Rng9 are required for Myo51's localizations to cytoplasmic puncta, actin cables, and the contractile ring. Myo51 puncta contain multiple Myo51 molecules and walk continuously on actin filaments in rng8(+) cells, whereas Myo51 forms speckles containing only one dimer and does not move efficiently on actin tracks in rng8Δ. Consistently, Myo51 transports artificial cargos efficiently in vivo, and this activity is regulated by Rng8. Purified Rng8 and Rng9 form stable higher-order complexes. Collectively, we propose that Rng8 and Rng9 form oligomers and cluster multiple Myo51 dimers to regulate Myo51 localization and functions.
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Affiliation(s)
- Ning Wang
- Department of Molecular Genetics, 2 Department of Molecular and Cellular Biochemistry, and 3 Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210
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26
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Coffman VC, Sees JA, Kovar DR, Wu JQ. The formins Cdc12 and For3 cooperate during contractile ring assembly in cytokinesis. ACTA ACUST UNITED AC 2013; 203:101-14. [PMID: 24127216 PMCID: PMC3798249 DOI: 10.1083/jcb.201305022] [Citation(s) in RCA: 41] [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
Both de novo-assembled actin filaments at the division site and existing filaments recruited by directional cortical transport contribute to contractile ring formation during cytokinesis. However, it is unknown which source is more important. Here, we show that fission yeast formin For3 is responsible for node condensation into clumps in the absence of formin Cdc12. For3 localization at the division site depended on the F-BAR protein Cdc15, and for3 deletion was synthetic lethal with mutations that cause defects in contractile ring formation. For3 became essential in cells expressing N-terminal truncations of Cdc12, which were more active in actin assembly but depended on actin filaments for localization to the division site. In tetrad fluorescence microscopy, double mutants of for3 deletion and cdc12 truncations were severely defective in contractile ring assembly and constriction, although cortical transport of actin filaments was normal. Together, these data indicate that different formins cooperate in cytokinesis and that de novo actin assembly at the division site is predominant for contractile ring formation.
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Affiliation(s)
- Valerie C Coffman
- Department of Molecular Genetics and 2 Department of Molecular and Cellular Biochemistry, The Ohio State University, Columbus, OH 43210
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27
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Model of fission yeast cell shape driven by membrane-bound growth factors and the cytoskeleton. PLoS Comput Biol 2013; 9:e1003287. [PMID: 24146607 PMCID: PMC3798282 DOI: 10.1371/journal.pcbi.1003287] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Accepted: 09/02/2013] [Indexed: 11/19/2022] Open
Abstract
Fission yeast serves as a model for how cellular polarization machinery consisting of signaling molecules and the actin and microtubule cytoskeleton regulates cell shape. In this work, we develop mathematical models to investigate how these cells maintain a tubular shape of approximately constant diameter. Many studies identify active Cdc42, found in a cap at the inner membrane of growing cell tips, as an important regulator of local cell wall remodeling, likely through control of exocyst tethering and the targeting of other polarity-enhancing structures. First, we show that a computational model with Cdc42-dependent local cell wall remodeling under turgor pressure predicts a relationship between spatial extent of growth signal and cell diameter that is in agreement with prior experiments. Second, we model the consequences of feedback between cell shape and distribution of Cdc42 growth signal at cell tips. We show that stability of cell diameter over successive cell divisions places restrictions on their mutual dependence. We argue that simple models where the spatial extent of the tip growth signal relies solely on geometrical alignment of confined microtubules might lead to unstable width regulation. Third, we study a computational model that combines a growth signal distributed over a characteristic length scale (as, for example, by a reaction-diffusion mechanism) with an axis-sensing microtubules system that places landmarks at positions where microtubule tips touch the cortex. A two-dimensional implementation of this model leads to stable cell diameter for a wide range of parameters. Changes to the parameters of this model reproduce straight, bent, and bulged cell shapes, and we discuss how this model is consistent with other observed cell shapes in mutants. Our work provides an initial quantitative framework for understanding the regulation of cell shape in fission yeast, and a scaffold for understanding this process on a more molecular level in the future. Fission yeast is a rod-shaped organism that is studied, in part, as a model for how cells develop and regulate their shape. Despite extensive work identifying effects of genetic mutations and pharmacological treatments on the shape of these cells, there is a lack of mathematical and computational models examining how internal cell signals and the cytoskeleton organize to remodel the cell wall, direct growth at cell tips, and maintain tubular shape. In this work we describe how the spatial distribution of regulatory protein signal at growing cell tips relates to cell diameter. Further, we describe the consequences of this signal depending on the shape of the cell, namely its length and diameter. Finally, we propose a computational model for understanding growth and shape that includes an axis-sensing microtubule system, landmarks delivered to cell tips along those microtubules, and a growth zone signal that moves around but is attracted to the landmarks. This picture explains a large number of reported abnormal shapes in terms of only a few modular components.
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28
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Zhu YH, Ye Y, Wu Z, Wu JQ. Cooperation between Rho-GEF Gef2 and its binding partner Nod1 in the regulation of fission yeast cytokinesis. Mol Biol Cell 2013; 24:3187-204. [PMID: 23966468 PMCID: PMC3806657 DOI: 10.1091/mbc.e13-06-0301] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Previous results showed that putative Rho-GEF Gef2 regulates division-site positioning during early cytokinesis in fission yeast. Here Nod1 is identified as a binding partner of Gef2. The two proteins form a complex to regulate division-site positioning and contractile-ring maintenance. In addition, Gef2 binds to GTPases Rho1, Rho4, and Rho5 in vitro. Cytokinesis is the last step of the cell-division cycle, which requires precise spatial and temporal regulation to ensure genetic stability. Rho guanine nucleotide exchange factors (Rho GEFs) and Rho GTPases are among the key regulators of cytokinesis. We previously found that putative Rho-GEF Gef2 coordinates with Polo kinase Plo1 to control the medial cortical localization of anillin-like protein Mid1 in fission yeast. Here we show that an adaptor protein, Nod1, colocalizes with Gef2 in the contractile ring and its precursor cortical nodes. Like gef2∆, nod1∆ has strong genetic interactions with various cytokinesis mutants involved in division-site positioning, suggesting a role of Nod1 in early cytokinesis. We find that Nod1 and Gef2 interact through the C-termini, which is important for their localization. The contractile-ring localization of Nod1 and Gef2 also depends on the interaction between Nod1 and the F-BAR protein Cdc15, where the Nod1/Gef2 complex plays a role in contractile-ring maintenance and affects the septation initiation network. Moreover, Gef2 binds to purified GTPases Rho1, Rho4, and Rho5 in vitro. Taken together, our data indicate that Nod1 and Gef2 function cooperatively in a protein complex to regulate fission yeast cytokinesis.
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Affiliation(s)
- Yi-Hua Zhu
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210 Department of Molecular and Cellular Biochemistry, The Ohio State University, Columbus, OH 43210 Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210
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Coffman VC, Wu JQ. Counting protein molecules using quantitative fluorescence microscopy. Trends Biochem Sci 2012; 37:499-506. [PMID: 22948030 DOI: 10.1016/j.tibs.2012.08.002] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Revised: 08/01/2012] [Accepted: 08/07/2012] [Indexed: 11/24/2022]
Abstract
In recent years, quantification of absolute protein numbers in cellular structures using fluorescence microscopy has become a reality. Two popular methods are available to a broad range of researchers with minimal equipment and analysis requirements: stepwise photobleaching to count discrete changes in intensity from a small number of fluorescent fusion proteins, and comparing the fluorescence intensity of a protein to a known in vivo or in vitro standard. This review summarizes the advantages and disadvantages of each method, and gives recent examples of each that answer important questions in their respective fields. We also highlight new counting methods that could become widely available in the future.
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Affiliation(s)
- Valerie C Coffman
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210, USA
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Saha S, Pollard TD. Characterization of structural and functional domains of the anillin-related protein Mid1p that contribute to cytokinesis in fission yeast. Mol Biol Cell 2012; 23:3993-4007. [PMID: 22918954 PMCID: PMC3469515 DOI: 10.1091/mbc.e12-07-0536] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Fission yeast cells depend on the anillin-related protein Mid1p for reliable cytokinesis. Insolubility limits the purification of full-length Mid1p for biophysical analysis, and lack of knowledge about the structural domains of Mid1p limits functional analysis. We addressed these limitations by identifying in a bacterial expression screen of random Mid1p fragments five soluble segments that can be purified and one insoluble segment. Using complementation experiments in Δmid1 cells, we tested the biological functions of these six putative domains that account for full-length Mid1p. The N-terminal domain (residues 1-149) is essential for correct positioning and orientation of septa. The third domain (residues 309-452) allows the construct composed of the first three domains (residues 1-452) to form hydrodynamically well-behaved octamers. Constructs consisting of residues 1-452 or 1-578 carry out most functions of full-length Mid1p, including concentration at the equatorial cortex in nodes that accumulate myosin-II and other contractile ring proteins during mitosis. However, cells depending on these constructs without the insoluble domain (residues 579-797) form equatorially located rings slowly from strands rather than by direct condensation of nodes. We conclude that residues 1-578 assemble node components myosin-II, Rng2p, and Cdc15p, and the insoluble domain facilitates the normal, efficient condensation of nodes into rings.
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Affiliation(s)
- Shambaditya Saha
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520-8103, USA
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Lee IJ, Coffman VC, Wu JQ. Contractile-ring assembly in fission yeast cytokinesis: Recent advances and new perspectives. Cytoskeleton (Hoboken) 2012; 69:751-63. [PMID: 22887981 DOI: 10.1002/cm.21052] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2012] [Accepted: 07/16/2012] [Indexed: 11/07/2022]
Abstract
The fission yeast Schizosaccharomyces pombe is an excellent model organism to study cytokinesis. Here, we review recent advances on contractile-ring assembly in fission yeast. First, we summarize the assembly of cytokinesis nodes, the precursors of a normal contractile ring. IQGAP Rng2 and myosin essential light chain Cdc4 are recruited by the anillin-like protein Mid1, followed by the addition of other cytokinesis node proteins. Mid1 localization on the plasma membrane is stabilized by interphase node proteins. Second, we discuss proteins and processes that contribute to the search, capture, pull, and release mechanism of contractile-ring assembly. Actin filaments nucleated by formin Cdc12, the motor activity of myosin-II, the stiffness of the actin network, and severing of actin filaments by cofilin all play essential roles in contractile-ring assembly. Finally, we discuss the Mid1-independent pathway for ring assembly, and the possible mechanisms underlying the ring maturation and constriction. Collectively, we provide an overview of the current understanding of contractile-ring assembly and uncover future directions in studying cytokinesis in fission yeast.
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Affiliation(s)
- I-Ju Lee
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio, USA
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Laporte D, Ojkic N, Vavylonis D, Wu JQ. α-Actinin and fimbrin cooperate with myosin II to organize actomyosin bundles during contractile-ring assembly. Mol Biol Cell 2012; 23:3094-110. [PMID: 22740629 PMCID: PMC3418305 DOI: 10.1091/mbc.e12-02-0123] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
During cytokinesis in Schizosaccharomyces pombe, the transient connections between nodes allow them to condense into the contractile ring. We find that α-actinin and fimbrin, two actin cross-linking proteins, are critical for node condensation as they stabilize transient linear actomyosin structures and thus modulate the morphology of the actomyosin network. The actomyosin contractile ring assembles through the condensation of a broad band of nodes that forms at the cell equator in fission yeast cytokinesis. The condensation process depends on actin filaments that interconnect nodes. By mutating or titrating actin cross-linkers α-actinin Ain1 and fimbrin Fim1 in live cells, we reveal that both proteins are involved in node condensation. Ain1 and Fim1 stabilize the actin cytoskeleton and modulate node movement, which prevents nodes and linear structures from aggregating into clumps and allows normal ring formation. Our computer simulations modeling actin filaments as semiflexible polymers reproduce the experimental observations and provide a model of how actin cross-linkers work with other proteins to regulate actin-filament orientations inside actin bundles and organize the actin network. As predicted by the simulations, doubling myosin II Myo2 level rescues the node condensation defects caused by Ain1 overexpression. Taken together, our work supports a cooperative process of ring self-organization driven by the interaction between actin filaments and myosin II, which is progressively stabilized by the cross-linking proteins.
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Affiliation(s)
- Damien Laporte
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210, USA
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Ye Y, Lee IJ, Runge KW, Wu JQ. Roles of putative Rho-GEF Gef2 in division-site positioning and contractile-ring function in fission yeast cytokinesis. Mol Biol Cell 2012; 23:1181-95. [PMID: 22298427 PMCID: PMC3315812 DOI: 10.1091/mbc.e11-09-0800] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
How Rho-GEFs and Rho GTPases regulate division-site selection during cytokinesis in fission yeast is unknown. The Rho-GEF Gef2 interacts with the anillin Mid1 to regulate contractile-ring positioning and assembly in coordination with the polo kinase Plo1. In addition, Gef2 is involved in contractile-ring stability and disassembly. Cytokinesis is crucial for integrating genome inheritance and cell functions. In multicellular organisms, Rho-guanine nucleotide exchange factors (GEFs) and Rho GTPases are key regulators of division-plane specification and contractile-ring formation during cytokinesis, but how they regulate early steps of cytokinesis in fission yeast remains largely unknown. Here we show that putative Rho-GEF Gef2 and Polo kinase Plo1 coordinate to control the medial cortical localization and function of anillin-related protein Mid1. The division-site positioning defects of gef2∆ plo1-ts18 double mutant can be partially rescued by increasing Mid1 levels. We find that Gef2 physically interacts with the Mid1 N-terminus and modulates Mid1 cortical binding. Gef2 localization to cortical nodes and the contractile ring depends on its last 145 residues, and the DBL-homology domain is important for its function in cytokinesis. Our data suggest the interaction between Rho-GEFs and anillins is an important step in the signaling pathways during cytokinesis. In addition, Gef2 also regulates contractile-ring function late in cytokinesis and may negatively regulate the septation initiation network. Collectively, we propose that Gef2 facilitates and stabilizes Mid1 binding to the medial cortex, where the localized Mid1 specifies the division site and induces contractile-ring assembly.
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Affiliation(s)
- Yanfang Ye
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210, USA
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