1
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Rezig IM, Yaduma WG, McInerny CJ. Processes Controlling the Contractile Ring during Cytokinesis in Fission Yeast, Including the Role of ESCRT Proteins. J Fungi (Basel) 2024; 10:154. [PMID: 38392827 PMCID: PMC10890238 DOI: 10.3390/jof10020154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Revised: 02/05/2024] [Accepted: 02/06/2024] [Indexed: 02/24/2024] Open
Abstract
Cytokinesis, as the last stage of the cell division cycle, is a tightly controlled process amongst all eukaryotes, with defective division leading to severe cellular consequences and implicated in serious human diseases and conditions such as cancer. Both mammalian cells and the fission yeast Schizosaccharomyces pombe use binary fission to divide into two equally sized daughter cells. Similar to mammalian cells, in S. pombe, cytokinetic division is driven by the assembly of an actomyosin contractile ring (ACR) at the cell equator between the two cell tips. The ACR is composed of a complex network of membrane scaffold proteins, actin filaments, myosin motors and other cytokinesis regulators. The contraction of the ACR leads to the formation of a cleavage furrow which is severed by the endosomal sorting complex required for transport (ESCRT) proteins, leading to the final cell separation during the last stage of cytokinesis, the abscission. This review describes recent findings defining the two phases of cytokinesis in S. pombe: ACR assembly and constriction, and their coordination with septation. In summary, we provide an overview of the current understanding of the mechanisms regulating ACR-mediated cytokinesis in S. pombe and emphasize a potential role of ESCRT proteins in this process.
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Affiliation(s)
- Imane M Rezig
- School of Molecular Biosciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Davidson Building, Glasgow G12 8QQ, UK
| | - Wandiahyel G Yaduma
- School of Molecular Biosciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Davidson Building, Glasgow G12 8QQ, UK
- Department of Chemistry, School of Sciences, Adamawa State College of Education, Hong 640001, Adamawa State, Nigeria
| | - Christopher J McInerny
- School of Molecular Biosciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Davidson Building, Glasgow G12 8QQ, UK
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2
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Igarashi MG, Bhattacharjee R, Willet AH, Gould KL. Polarity kinases that phosphorylate F-BAR protein Cdc15 have unique localization patterns during cytokinesis and contributions to preventing tip septation in Schizosaccharomyces pombe. MICROPUBLICATION BIOLOGY 2023; 2023:10.17912/micropub.biology.000965. [PMID: 37746062 PMCID: PMC10517346 DOI: 10.17912/micropub.biology.000965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Figures] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 09/01/2023] [Accepted: 09/07/2023] [Indexed: 09/26/2023]
Abstract
The Schizosaccharomyces pombe F-BAR protein, Cdc15, facilitates the linkage between the cytokinetic ring and the plasma membrane. Cdc15 is phosphorylated on many sites by four polarity kinases and this antagonizes membrane interaction. Dephosphorylation of Cdc15 during mitosis induces its phase separation, allowing oligomerization, membrane association, and protein partner binding. Here, using live cell imaging we examined whether spatial separation of Cdc15 from its four identified kinases potentially explains their diverse effects on tip septation and the mitotic Cdc15 phosphorylation state. We identified a correlation between kinase localization and their ability to antagonize Cdc15 cytokinetic ring and membrane localization.
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Affiliation(s)
- Maya G. Igarashi
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, US
- Current address: Biophysical Sciences, University of Chicago, Chicago, IL, US
| | - Rahul Bhattacharjee
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, US
- Current address: Twist Bioscience, Quincy, MA, US
| | - Alaina H. Willet
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, US
| | - Kathleen L. Gould
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, US
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3
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Rezig IM, Yaduma WG, Gould GW, McInerny CJ. The role of anillin/Mid1p during medial division and cytokinesis: from fission yeast to cancer cells. Cell Cycle 2023; 22:633-644. [PMID: 36426865 PMCID: PMC9980708 DOI: 10.1080/15384101.2022.2147655] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Cytokinesis is the final stage of cell division cycle when cellular constituents are separated to produce two daughter cells. This process is driven by the formation and constriction of a contractile ring. Progression of these events is controlled by mechanisms and proteins that are evolutionary conserved in eukaryotes from fungi to humans. Genetic and molecular studies in different model organisms identified essential cytokinesis genes, with several conserved proteins, including the anillin/Mid1p proteins, constituting the core cytokinetic machinery. The fission yeast Schizosaccharomyces pombe represents a well-established model organism to study eukaryotic cell cycle regulation. Cytokinesis in fission yeast and mammalian cells depends on the placement, assembly, maturation, and constriction of a medially located actin-myosin contractile ring (ACR). Here, we review aspects of the ACR assembly and cytokinesis process in fission yeast and consider the regulation of such events in mammalian cells. First, we briefly describe the role of anillin during mammalian ACR assembly and cytokinesis. Second, we describe different aspects of the anillin-like protein Mid1p regulation during the S. pombe cell cycle, including its structure, function, and phospho-regulation. Third, we briefly discuss Mid1pindependent ACR assembly in S. pombe. Fourth, we highlight emerging studies demonstrating the roles of anillin in human tumourigenesis introducing anillin as a potential drug target for cancer treatment. Collectively, we provide an overview of the current understanding of medial division and cytokinesis in S. pombe and suggest the implications of these observations in other eukaryotic organisms, including humans.
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Affiliation(s)
- Imane M. Rezig
- School of Molecular Biosciences, College of Medical, Veterinary and Life Sciences, Davidson Building, University of Glasgow, Glasgow, UK
| | - Wandiahyel G. Yaduma
- School of Molecular Biosciences, College of Medical, Veterinary and Life Sciences, Davidson Building, University of Glasgow, Glasgow, UK,Department of Chemistry, School of Sciences, Adamawa State College of Education Hong, Nigeria
| | - Gwyn W. Gould
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK
| | - Christopher J. McInerny
- School of Molecular Biosciences, College of Medical, Veterinary and Life Sciences, Davidson Building, University of Glasgow, Glasgow, UK,CONTACT Christopher J. McInerny School of Molecular Biosciences, College of Medical, Veterinary and Life Sciences, Davidson Building, University of Glasgow, GlasgowG12 8QQ, UK
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4
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Abstract
The most fundamental feature of cellular form is size, which sets the scale of all cell biological processes. Growth, form, and function are all necessarily linked in cell biology, but we often do not understand the underlying molecular mechanisms nor their specific functions. Here, we review progress toward determining the molecular mechanisms that regulate cell size in yeast, animals, and plants, as well as progress toward understanding the function of cell size regulation. It has become increasingly clear that the mechanism of cell size regulation is deeply intertwined with basic mechanisms of biosynthesis, and how biosynthesis can be scaled (or not) in proportion to cell size. Finally, we highlight recent findings causally linking aberrant cell size regulation to cellular senescence and their implications for cancer therapies.
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Affiliation(s)
- Shicong Xie
- Department of Biology, Stanford University, Stanford, California, USA;
| | - Matthew Swaffer
- Department of Biology, Stanford University, Stanford, California, USA;
| | - Jan M Skotheim
- Department of Biology, Stanford University, Stanford, California, USA;
- Chan Zuckerberg Biohub, San Francisco, California, USA
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5
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Cuny AP, Schlottmann FP, Ewald JC, Pelet S, Schmoller KM. Live cell microscopy: From image to insight. BIOPHYSICS REVIEWS 2022; 3:021302. [PMID: 38505412 PMCID: PMC10903399 DOI: 10.1063/5.0082799] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Accepted: 03/18/2022] [Indexed: 03/21/2024]
Abstract
Live-cell microscopy is a powerful tool that can reveal cellular behavior as well as the underlying molecular processes. A key advantage of microscopy is that by visualizing biological processes, it can provide direct insights. Nevertheless, live-cell imaging can be technically challenging and prone to artifacts. For a successful experiment, many careful decisions are required at all steps from hardware selection to downstream image analysis. Facing these questions can be particularly intimidating due to the requirement for expertise in multiple disciplines, ranging from optics, biophysics, and programming to cell biology. In this review, we aim to summarize the key points that need to be considered when setting up and analyzing a live-cell imaging experiment. While we put a particular focus on yeast, many of the concepts discussed are applicable also to other organisms. In addition, we discuss reporting and data sharing strategies that we think are critical to improve reproducibility in the field.
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Affiliation(s)
| | - Fabian P. Schlottmann
- Interfaculty Institute of Cell Biology, University of Tuebingen, 72076 Tuebingen, Germany
| | - Jennifer C. Ewald
- Interfaculty Institute of Cell Biology, University of Tuebingen, 72076 Tuebingen, Germany
| | - Serge Pelet
- Department of Fundamental Microbiology, University of Lausanne, 1015 Lausanne, Switzerland
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6
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Shin JH, Kim HY, Fu T, Lee KH, Kim KS. CsPOM1, a DYRK Family Kinase, Plays Diverse Roles in Fungal Development, Virulence, and Stress Tolerance in the Anthracnose Pathogen Colletotrichum scovillei. Front Cell Infect Microbiol 2022; 12:861915. [PMID: 35558103 PMCID: PMC9088010 DOI: 10.3389/fcimb.2022.861915] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 03/23/2022] [Indexed: 11/24/2022] Open
Abstract
Colletotrichum scovillei is the major anthracnose fungus of sweet pepper and chili pepper (Capsicum annuum L.), causing significant losses in the yield and quality of the pepper fruits. Molecular mechanisms governing development and pathogenicity have been widely studied in many foliar fungal pathogens, but the information on fruit diseases is still limited. In this study, we determined the functional roles of the dual-specificity tyrosine phosphorylation-regulated kinase CsPOM1 in C. scovillei. Knockout mutant for CsPOM1 gene was obtained via homology-dependent gene replacement. The ΔCspom1 mutant exhibited a reduction in vegetative growth on osmotic stress, surface hydrophobicity, and conidiation compared with wild-type. Conidia of the ΔCspom1 mutant were already two-celled before inoculation on an induction surface, indicating that CsPOM1 negatively regulates conidial cell division. The ΔCspom1 mutant, similar to wild-type, formed appressoria on the plant surface, but was significantly reduced on hydrophobic coverslips, probably due to a defect in the recognition of surface hydrophobicity. Treatment of conidia with cutin monomers restored appressorium formation on hydrophobic coverslips in the ΔCspom1 mutant. On pepper fruits, the ΔCspom1 mutant exhibited delayed penetration and invasive growth, leading to significantly reduced virulence. Collectively, the results showed that CsPOM1 is important for stress tolerance, conidiation, surface hydrophobicity, appressorium formation, and virulence in C. scovillei.
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7
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Gerganova V, Lamas I, Rutkowski DM, Vještica A, Castro DG, Vincenzetti V, Vavylonis D, Martin SG. Cell patterning by secretion-induced plasma membrane flows. SCIENCE ADVANCES 2021; 7:eabg6718. [PMID: 34533984 PMCID: PMC8448446 DOI: 10.1126/sciadv.abg6718] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 07/26/2021] [Indexed: 05/20/2023]
Abstract
Cells self-organize using reaction-diffusion and fluid-flow principles. Whether bulk membrane flows contribute to cell patterning has not been established. Here, using mathematical modeling, optogenetics, and synthetic probes, we show that polarized exocytosis causes lateral membrane flows away from regions of membrane insertion. Plasma membrane–associated proteins with sufficiently low diffusion and/or detachment rates couple to the flows and deplete from areas of exocytosis. In rod-shaped fission yeast cells, zones of Cdc42 GTPase activity driving polarized exocytosis are limited by GTPase activating proteins (GAPs). We show that membrane flows pattern the GAP Rga4 distribution and that coupling of a synthetic GAP to membrane flows is sufficient to establish the rod shape. Thus, membrane flows induced by Cdc42-dependent exocytosis form a negative feedback restricting the zone of Cdc42 activity.
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Affiliation(s)
- Veneta Gerganova
- Department of Fundamental Microbiology, University of Lausanne, CH-1015, Switzerland
| | - Iker Lamas
- Department of Fundamental Microbiology, University of Lausanne, CH-1015, Switzerland
| | | | - Aleksandar Vještica
- Department of Fundamental Microbiology, University of Lausanne, CH-1015, Switzerland
| | - Daniela Gallo Castro
- Department of Fundamental Microbiology, University of Lausanne, CH-1015, Switzerland
| | - Vincent Vincenzetti
- Department of Fundamental Microbiology, University of Lausanne, CH-1015, Switzerland
| | - Dimitrios Vavylonis
- Department of Physics, Lehigh University, Bethlehem, PA 18015, USA
- Corresponding author. (S.G.M.); (D.V.)
| | - Sophie G. Martin
- Department of Fundamental Microbiology, University of Lausanne, CH-1015, Switzerland
- Corresponding author. (S.G.M.); (D.V.)
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8
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Abstract
In the context of animal or plant development, we tend to think of cells as small, simple, building blocks, such that complex patterns or shapes can only be constructed from large numbers of cells, with cells in different parts of the organism taking on different fates. However, cells themselves are far from simple, and often take on complex shapes with a remarkable degree of intracellular patterning. How do these patterns arise? As in embryogenesis, the development of structure inside a cell can be broken down into a number of basic processes. For each part of the cell, morphogenetic processes create internal structures such as organelles, which might correspond to organs at the level of a whole organism. Given that mechanisms exist to generate parts, patterning processes are required to ensure that the parts are distributed in the correct arrangement relative to the rest of the cell. Such patterning processes make reference to global polarity axes, requiring mechanisms for axiation which, in turn, require processes to break symmetry. These fundamental processes of symmetry breaking, axiation, patterning, and morphogenesis have been extensively studied in developmental biology but less so at the subcellular level. This review will focus on developmental processes that give eukaryotic cells their complex structures, with a focus on cytoskeletal organization in free-living cells, ciliates in particular, in which these processes are most readily apparent.
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9
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Gerganova V, Bhatia P, Vincenzetti V, Martin SG. Direct and indirect regulation of Pom1 cell size pathway by the protein phosphatase 2C Ptc1. Mol Biol Cell 2021; 32:703-711. [PMID: 33625871 PMCID: PMC8108516 DOI: 10.1091/mbc.e20-08-0508] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The fission yeast cells Schizosaccharomyces pombe divide at constant cell size regulated by environmental stimuli. An important pathway of cell size control involves the membrane-associated DYRK-family kinase Pom1, which forms decreasing concentration gradients from cell poles and inhibits mitotic inducers at midcell. Here, we identify the phosphatase 2C Ptc1 as negative regulator of Pom1. Ptc1 localizes to cell poles in a manner dependent on polarity and cell-wall integrity factors. We show that Ptc1 directly binds Pom1 and can dephosphorylate it in vitro but modulates Pom1 localization indirectly upon growth in low-glucose conditions by influencing microtubule stability. Thus, Ptc1 phosphatase plays both direct and indirect roles in the Pom1 cell size control pathway.
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Affiliation(s)
- Veneta Gerganova
- Department of Fundamental Microbiology, University of Lausanne, 1015 Lausanne, Switzerland
| | - Payal Bhatia
- Department of Fundamental Microbiology, University of Lausanne, 1015 Lausanne, Switzerland
| | - Vincent Vincenzetti
- Department of Fundamental Microbiology, University of Lausanne, 1015 Lausanne, Switzerland
| | - Sophie G Martin
- Department of Fundamental Microbiology, University of Lausanne, 1015 Lausanne, Switzerland
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10
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Scotchman E, Kume K, Navarro FJ, Nurse P. Identification of mutants with increased variation in cell size at onset of mitosis in fission yeast. J Cell Sci 2021; 134:jcs251769. [PMID: 33419777 PMCID: PMC7888708 DOI: 10.1242/jcs.251769] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 12/10/2020] [Indexed: 12/19/2022] Open
Abstract
Fission yeast cells divide at a similar cell length with little variation about the mean. This is thought to be the result of a control mechanism that senses size and corrects for any deviations by advancing or delaying onset of mitosis. Gene deletions that advance cells into mitosis at a smaller size or delay cells entering mitosis have led to the identification of genes potentially involved in this mechanism. However, the molecular basis of this control is still not understood. In this work, we have screened for genes that when deleted increase the variability in size of dividing cells. The strongest candidate identified in this screen was mga2 The mga2 deletion strain shows a greater variation in cell length at division, with a coefficient of variation (CV) of 15-24%, while the wild-type strain has a CV of 5-8%. Furthermore, unlike wild-type cells, the mga2 deletion cells are unable to correct cell size deviations within one cell cycle. We show that the mga2 gene genetically interacts with nem1 and influences the nuclear membrane and the nuclear-cytoplasmic transport of CDK regulators.
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Affiliation(s)
| | - Kazunori Kume
- Cell Cycle Laboratory, The Francis Crick Institute, London NW1 1AT, UK
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8530, Japan
- Hiroshima Research Center for Healthy Aging (HiHA), Hiroshima University,Higashi-Hiroshima, Hiroshima 739-8530, Japan
| | | | - Paul Nurse
- Cell Cycle Laboratory, The Francis Crick Institute, London NW1 1AT, UK
- Laboratory of Yeast Genetics and Cell Biology, Rockefeller University, New York, NY 10065, USA
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11
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Gu Y, Oliferenko S. The principles of cellular geometry scaling. Curr Opin Cell Biol 2020; 68:20-27. [PMID: 32950004 DOI: 10.1016/j.ceb.2020.08.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 08/14/2020] [Accepted: 08/17/2020] [Indexed: 01/11/2023]
Abstract
Cellular dimensions profoundly influence cellular physiology. For unicellular organisms, this has direct bearing on their ecology and evolution. The morphology of a cell is governed by scaling rules. As it grows, the ratio of its surface area to volume is expected to decrease. Similarly, if environmental conditions force proliferating cells to settle on different size optima, cells of the same type may exhibit size-dependent variation in cellular processes. In fungi, algae and plants where cells are surrounded by a rigid wall, division at smaller size often produces immediate changes in geometry, decreasing cell fitness. Here, we discuss how cells interpret their size, buffer against changes in shape and, if necessary, scale their polarity to maintain optimal shape at different cell volumes.
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Affiliation(s)
- Ying Gu
- The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK; Randall Centre for Cell and Molecular Biophysics, School of Basic and Medical Biosciences, King's College London, London, SE1 1UL, UK
| | - Snezhana Oliferenko
- The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK; Randall Centre for Cell and Molecular Biophysics, School of Basic and Medical Biosciences, King's College London, London, SE1 1UL, UK.
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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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Brzeska H, Gonzalez J, Korn ED, Titus MA. Basic-hydrophobic sites are localized in conserved positions inside and outside of PH domains and affect localization of Dictyostelium myosin 1s. Mol Biol Cell 2020; 31:101-117. [PMID: 31774725 PMCID: PMC6960411 DOI: 10.1091/mbc.e19-08-0475] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 11/14/2019] [Accepted: 11/22/2019] [Indexed: 11/21/2022] Open
Abstract
Myosin 1s have critical roles in linking membranes to the actin cytoskeleton via direct binding to acidic lipids. Lipid binding may occur through PIP3/PIP2-specific PH domains or nonspecific ionic interactions involving basic-hydrophobic (BH) sites but the mechanism of myosin 1s distinctive lipid targeting is poorly understood. Now we show that PH domains occur in all Dictyostelium myosin 1s and that the BH sites of Myo1A, B, C, D, and F are in conserved positions near the β3/β4 loops of their PH domains. In spite of these shared lipid-binding sites, we observe significant differences in myosin 1s highly dynamic localizations. All myosin 1s except Myo1A are present in macropinocytic structures but only Myo1B and Myo1C are enriched at the edges of macropinocytic cups and associate with the actin in actin waves. In contrast, Myo1D, E, and F are enclosed by the actin wave. Mutations of BH sites affect localization of all Dictyostelium myosin 1s. Notably, mutation of the BH site located within the PH domains of PIP3-specific Myo1D and Myo1F completely eradicates membrane binding. Thus, BH sites are important determinants of motor targeting and may have a similar role in the localization of other myosin 1s.
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Affiliation(s)
- Hanna Brzeska
- Laboratory of Cell Biology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892
| | - Jesus Gonzalez
- Laboratory of Cell Biology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892
| | - Edward D. Korn
- Laboratory of Cell Biology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892
| | - Margaret A. Titus
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN 55455
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14
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Vještica A, Marek M, Nkosi PJ, Merlini L, Liu G, Bérard M, Billault-Chaumartin I, Martin SG. A toolbox of stable integration vectors in the fission yeast Schizosaccharomyces pombe. J Cell Sci 2020; 133:jcs.240754. [PMID: 31801797 DOI: 10.1242/jcs.240754] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Accepted: 11/24/2019] [Indexed: 12/14/2022] Open
Abstract
Schizosaccharomyces pombe is a widely used model organism to study many aspects of eukaryotic cell physiology. Its popularity as an experimental system partially stems from the ease of genetic manipulations, where the innate homology-targeted repair is exploited to precisely edit the genome. While vectors to incorporate exogenous sequences into the chromosomes are available, most are poorly characterized. Here, we show that commonly used fission yeast vectors, which upon integration produce repetitive genomic regions, give rise to unstable genomic loci. We overcome this problem by designing a new series of stable integration vectors (SIVs) that target four different prototrophy genes. SIVs produce non-repetitive, stable genomic loci and integrate predominantly as single copy. Additionally, we develop a set of complementary auxotrophic alleles that preclude false-positive integration events. We expand the vector series to include antibiotic resistance markers, promoters, fluorescent tags and terminators, and build a highly modular toolbox to introduce heterologous sequences. Finally, as proof of concept, we generate a large set of ready-to-use, fluorescent probes to mark organelles and cellular processes with a wide range of applications in fission yeast research.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Aleksandar Vještica
- Department of Fundamental Microbiology, University of Lausanne, Biophore building, CH-1015 Lausanne, Switzerland
| | - Magdalena Marek
- Department of Fundamental Microbiology, University of Lausanne, Biophore building, CH-1015 Lausanne, Switzerland
| | - Pedro Junior Nkosi
- Department of Fundamental Microbiology, University of Lausanne, Biophore building, CH-1015 Lausanne, Switzerland
| | - Laura Merlini
- Department of Fundamental Microbiology, University of Lausanne, Biophore building, CH-1015 Lausanne, Switzerland
| | - Gaowen Liu
- Department of Fundamental Microbiology, University of Lausanne, Biophore building, CH-1015 Lausanne, Switzerland
| | - Melvin Bérard
- Department of Fundamental Microbiology, University of Lausanne, Biophore building, CH-1015 Lausanne, Switzerland
| | - Ingrid Billault-Chaumartin
- Department of Fundamental Microbiology, University of Lausanne, Biophore building, CH-1015 Lausanne, Switzerland
| | - Sophie G Martin
- Department of Fundamental Microbiology, University of Lausanne, Biophore building, CH-1015 Lausanne, Switzerland
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15
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Abstract
The notion that graded distributions of signals underlie the spatial organization of biological systems has long been a central pillar in the fields of cell and developmental biology. During morphogenesis, morphogens spread across tissues to guide development of the embryo. Similarly, a variety of dynamic gradients and pattern-forming networks have been discovered that shape subcellular organization. Here we discuss the principles of intracellular pattern formation by these intracellular morphogens and relate them to conceptually similar processes operating at the tissue scale. We will specifically review mechanisms for generating cellular asymmetry and consider how intracellular patterning networks are controlled and adapt to cellular geometry. Finally, we assess the general concept of intracellular gradients as a mechanism for positional control in light of current data, highlighting how the simple readout of fixed concentration thresholds fails to fully capture the complexity of spatial patterning processes occurring inside cells.
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Affiliation(s)
- Lars Hubatsch
- Max Planck Institute for the Physics of Complex Systems, Dresden, Germany
| | - Nathan W Goehring
- The Francis Crick Institute, London, United Kingdom; Institute for the Physics of Living Systems, University College London, London, United Kingdom; MRC Laboratory for Molecular Cell Biology, University College London, London, United Kingdom.
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Ağuş HH, Yilmaz S, Şengöz CO. Crosstalk between autophagy and apoptosis induced by camphor in Schizosaccharomyces pombe. ACTA ACUST UNITED AC 2019; 43:382-390. [PMID: 31892813 PMCID: PMC6911262 DOI: 10.3906/biy-1908-11] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Camphor is widely used in pharmacy, the food industry, and cosmetics. In this study, we evaluate inhibitory and cytotoxic effects of camphor in the fission yeast (Schizosaccharomyces pombe), which presents a unicellular model in mechanistic toxicology and cell biology. Low-dose camphor exposure (0.4 mg/mL) activated autophagy, which was shown by GFP-Atg8 dots and transcriptional upregulation of Atg6 (Beclin-1 ortholog). Autophagy was also confirmed by using autophagy-deficient cells, which showed reduction in GFP-Atg8 dot formation. However, high-dose camphor exposure (0.8 mg/mL) caused dramatic cell death ratios, demonstrated by spot and colony-forming assays, even in autophagy-deficient cells. To unravel the underlying mechanism, this time, apoptosis-deficient cells were exposed to low- and high-dose camphor. Apoptosis was also confirmed by acridine orange/ethidium bromide staining. Among yeast apoptosis mediators, Aif1 was found to mediate camphor-induced cell death. In conclusion, differential regulation of autophagy and apoptosis, and switches between them, were found to be dose-dependent. The potential effects of camphor on autophagy and apoptotic cell death and underlying mechanisms were clarified in basic unicellular eukaryotic model, S. pombe.
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Affiliation(s)
- Hızlan Hıncal Ağuş
- Department of Molecular Biology and Genetics, Faculty of Arts & Science, İstanbul Yeni Yüzyıl University, İstanbul Turkey
| | - Sedanur Yilmaz
- Department of Molecular Biology and Genetics, Faculty of Arts & Science, İstanbul Yeni Yüzyıl University, İstanbul Turkey
| | - Cansın Ogeday Şengöz
- Department of Molecular Biology and Genetics, Faculty of Arts & Science, İstanbul Yeni Yüzyıl University, İstanbul Turkey
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Opalko HE, Nasa I, Kettenbach AN, Moseley JB. A mechanism for how Cdr1/Nim1 kinase promotes mitotic entry by inhibiting Wee1. Mol Biol Cell 2019; 30:3015-3023. [PMID: 31644361 PMCID: PMC6880885 DOI: 10.1091/mbc.e19-08-0430] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
To enter into mitosis, cells must shut off the cell cycle inhibitor Wee1. SAD family protein kinases regulate Wee1 signaling in yeast and humans. In Schizosaccharomyces pombe, two SAD kinases (Cdr1/Nim1 and Cdr2) act as upstream inhibitors of Wee1. Previous studies found that S. pombe Cdr1/Nim1 directly phosphorylates and inhibits Wee1 in vitro, but different results were obtained for budding yeast and human SAD kinases. Without a full understanding of Cdr1 action on Wee1, it has been difficult to assess the in vivo relevance and conservation of this mechanism. Here, we show that both Cdr1 and Cdr2 promote Wee1 phosphorylation in cells, but only Cdr1 inhibits Wee1 kinase activity. Inhibition occurs when Cdr1 phosphorylates a cluster of serine residues linking α-helices G and H of the Wee1 kinase domain. This region is highly divergent among different Wee1 proteins, consistent with distinct regulatory mechanisms. A wee(4A) mutant that impairs phosphorylation by Cdr1 delays mitotic entry and causes elongated cells. By disrupting and retargeting Cdr1 localization, we show that Cdr1 inhibition of Wee1 occurs in cells at cortical nodes formed by Cdr2. On the basis of our results, we propose a two-step model for inhibition of Wee1 by Cdr1 and Cdr2 at nodes.
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Affiliation(s)
- Hannah E Opalko
- Department of Biochemistry and Cell Biology, The Geisel School of Medicine at Dartmouth, Hanover, NH 03755
| | - Isha Nasa
- Department of Biochemistry and Cell Biology, The Geisel School of Medicine at Dartmouth, Hanover, NH 03755.,Norris Cotton Cancer Center, The Geisel School of Medicine at Dartmouth, Lebanon, NH 03756
| | - Arminja N Kettenbach
- Department of Biochemistry and Cell Biology, The Geisel School of Medicine at Dartmouth, Hanover, NH 03755.,Norris Cotton Cancer Center, The Geisel School of Medicine at Dartmouth, Lebanon, NH 03756
| | - James B Moseley
- Department of Biochemistry and Cell Biology, The Geisel School of Medicine at Dartmouth, Hanover, NH 03755
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