1
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Yang EJN, Liao PC, Pon L. Mitochondrial protein and organelle quality control-Lessons from budding yeast. IUBMB Life 2024; 76:72-87. [PMID: 37731280 PMCID: PMC10842221 DOI: 10.1002/iub.2783] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 08/11/2023] [Indexed: 09/22/2023]
Abstract
Mitochondria are essential for normal cellular function and have emerged as key aging determinants. Indeed, defects in mitochondrial function have been linked to cardiovascular, skeletal muscle and neurodegenerative diseases, premature aging, and age-linked diseases. Here, we describe mechanisms for mitochondrial protein and organelle quality control. These surveillance mechanisms mediate repair or degradation of damaged or mistargeted mitochondrial proteins, segregate mitochondria based on their functional state during asymmetric cell division, and modulate cellular fitness, the response to stress, and lifespan control in yeast and other eukaryotes.
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Affiliation(s)
- Emily Jie-Ning Yang
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, NY 10032
| | - Pin-Chao Liao
- Institute of Molecular Medicine & Department of Life Science, National Tsing Hua University, Hsinchu, Taiwan 30013
| | - Liza Pon
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, NY 10032
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2
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González B, Aldea M, Cullen PJ. Chaperone-Dependent Degradation of Cdc42 Promotes Cell Polarity and Shields the Protein from Aggregation. Mol Cell Biol 2023; 43:200-222. [PMID: 37114947 PMCID: PMC10184603 DOI: 10.1080/10985549.2023.2198171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 03/02/2023] [Accepted: 03/06/2023] [Indexed: 04/29/2023] Open
Abstract
Rho GTPases are global regulators of cell polarity and signaling. By exploring the turnover regulation of the yeast Rho GTPase Cdc42p, we identified new regulatory features surrounding the stability of the protein. We specifically show that Cdc42p is degraded at 37 °C by chaperones through lysine residues located in the C-terminus of the protein. Cdc42p turnover at 37 °C occurred by the 26S proteasome in an ESCRT-dependent manner in the lysosome/vacuole. By analyzing versions of Cdc42p that were defective for turnover, we show that turnover at 37 °C promoted cell polarity but was defective for sensitivity to mating pheromone, presumably mediated through a Cdc42p-dependent MAP kinase pathway. We also identified one residue (K16) in the P-loop of the protein that was critical for Cdc42p stability. Accumulation of Cdc42pK16R in some contexts led to the formation of protein aggregates, which were enriched in aging mother cells and cells undergoing proteostatic stress. Our study uncovers new aspects of protein turnover regulation of a Rho-type GTPase that may extend to other systems. Moreover, residues identified here that mediate Cdc42p turnover correlate with several human diseases, which may suggest that turnover regulation of Cdc42p is important to aspects of human health.
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Affiliation(s)
- Beatriz González
- Department of Biological Sciences, State University of New York at Buffalo, New York, USA
| | - Martí Aldea
- Molecular Biology Institute of Barcelona (IBMB), CSIC, Barcelona, Spain
| | - Paul J. Cullen
- Department of Biological Sciences, State University of New York at Buffalo, New York, USA
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3
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Sharmeen N, Law C, Wu C. Polarization and cell-fate decision facilitated by the adaptor Ste50p in Saccharomyces cerevisiae. PLoS One 2022; 17:e0278614. [PMID: 36538537 PMCID: PMC9767377 DOI: 10.1371/journal.pone.0278614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Accepted: 11/18/2022] [Indexed: 12/24/2022] Open
Abstract
In response to pheromone, many proteins localize on the plasma membrane of yeast cell to reform it into a polarized shmoo structure. The adaptor protein Ste50p, known as a pheromone signal enhancer critical for shmoo polarization, has never been explored systematically for its localization and function in the polarization process. Time-lapse single-cell imaging and quantitation shown here characterizes Ste50p involvement in the establishment of cell polarity. We found that Ste50p patches on the cell cortex mark the point of shmoo initiation, these patches could move, and remain associated with the growing shmoo tip in a pheromone concentration time-dependent manner until shmoo maturation. A Ste50p mutant impaired in patch localization suffers a delay in polarization. By quantitative analysis we show that polarization correlates with the rising levels of Ste50p, enabling rapid cell responses to pheromone that correspond to a critical level of Ste50p at the initial G1 phase. We exploited the quantitative differences in the pattern of Ste50p expression to correlate with the cell-cell phenotypic heterogeneity, showing Ste50p involvement in the cellular differentiation choice. Taken together, these findings present Ste50p to be part of the early shmoo development phase, suggesting that Ste50p may be involved with the polarisome in the initiation of polarization, and plays a role in regulating the polarized growth of shmoo during pheromone response.
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Affiliation(s)
- Nusrat Sharmeen
- Division of Experimental Medicine, Department of Medicine, McGill University, Montreal, Quebec, Canada
- * E-mail:
| | - Chris Law
- Centre for Microscopy and Cellular Imaging, Department of Biology, Concordia University, Montreal, Quebec, Canada
| | - Cunle Wu
- Division of Experimental Medicine, Department of Medicine, McGill University, Montreal, Quebec, Canada
- Human Health Therapeutics Research Centre, National Research Council Canada, Montreal, Quebec, Canada
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4
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González B, Cullen PJ. Regulation of Cdc42 protein turnover modulates the filamentous growth MAPK pathway. J Cell Biol 2022; 221:213675. [PMID: 36350310 PMCID: PMC9811999 DOI: 10.1083/jcb.202112100] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 05/25/2022] [Accepted: 09/19/2022] [Indexed: 11/11/2022] Open
Abstract
Rho GTPases are central regulators of cell polarity and signaling. How Rho GTPases are directed to function in certain settings remains unclear. Here, we show the protein levels of the yeast Rho GTPase Cdc42p are regulated, which impacts a subset of its biological functions. Specifically, the active conformation of Cdc42p was ubiquitinated by the NEDD4 ubiquitin ligase Rsp5p and HSP40/HSP70 chaperones and turned over in the proteasome. A GTP-locked (Q61L) turnover-defective (TD) version, Cdc42pQ61L+TD, hyperactivated the MAPK pathway that regulates filamentous growth (fMAPK). Cdc42pQ61L+TD did not influence the activity of the mating pathway, which shares components with the fMAPK pathway. The fMAPK pathway adaptor, Bem4p, stabilized Cdc42p levels, which resulted in elevated fMAPK pathway signaling. Our results identify Cdc42p turnover regulation as being critical for the regulation of a MAPK pathway. The control of Rho GTPase levels by stabilization and turnover may be a general feature of signaling pathway regulation, which can result in the execution of a specific developmental program.
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Affiliation(s)
- Beatriz González
- Department of Biological Sciences, State University of New York at Buffalo, Buffalo, NY
| | - Paul J. Cullen
- Department of Biological Sciences, State University of New York at Buffalo, Buffalo, NY,Correspondence to Paul J. Cullen:
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5
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A role for cell polarity in lifespan and mitochondrial quality control in the budding yeast Saccharomyces cerevisiae. iScience 2022; 25:103957. [PMID: 35281729 PMCID: PMC8914336 DOI: 10.1016/j.isci.2022.103957] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 12/15/2021] [Accepted: 02/17/2022] [Indexed: 01/03/2023] Open
Abstract
Babies are born young, largely independent of the age of their mothers. Mother-daughter age asymmetry in yeast is achieved, in part, by inheritance of higher-functioning mitochondria by buds and retention of some high-functioning mitochondria in mother cells. The mitochondrial F box protein, Mfb1p, tethers mitochondria at both poles in a cell cycle-regulated manner: it localizes to and anchors mitochondria at the mother cell tip throughout the cell cycle and at the bud tip before cytokinesis. Here, we report that cell polarity and polarized localization of Mfb1p decline with age in Saccharomyces cerevisiae. Moreover, deletion of genes (BUD1, BUD2, and BUD5) that mediate symmetry breaking during establishment of cell polarity and asymmetric yeast cell division cause depolarized Mfb1p localization and defects in mitochondrial distribution and quality control. Our results support a role for the polarity machinery in lifespan through modulating Mfb1 function in asymmetric inheritance of mitochondria during yeast cell division. Budding polarity declines with age Polarization of a mitochondrial tether, Mfb1p, within mother cells declines with age Defects in budding polarity disrupt Mfb1p polarization and mitochondrial distribution Polarity defects affect Mfb1p-mediated mitochondrial quality and lifespan control
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Hörning M, Bullmann T, Shibata T. Local Membrane Curvature Pins and Guides Excitable Membrane Waves in Chemotactic and Macropinocytic Cells - Biomedical Insights From an Innovative Simple Model. Front Cell Dev Biol 2021; 9:670943. [PMID: 34604207 PMCID: PMC8479871 DOI: 10.3389/fcell.2021.670943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 08/16/2021] [Indexed: 11/13/2022] Open
Abstract
PIP3 dynamics observed in membranes are responsible for the protruding edge formation in cancer and amoeboid cells. The mechanisms that maintain those PIP3 domains in three-dimensional space remain elusive, due to limitations in observation and analysis techniques. Recently, a strong relation between the cell geometry, the spatial confinement of the membrane, and the excitable signal transduction system has been revealed by Hörning and Shibata (2019) using a novel 3D spatiotemporal analysis methodology that enables the study of membrane signaling on the entire membrane (Hörning and Shibata, 2019). Here, using 3D spatial fluctuation and phase map analysis on actin polymerization inhibited Dictyostelium cells, we reveal a spatial asymmetry of PIP3 signaling on the membrane that is mediated by the contact perimeter of the plasma membrane — the spatial boundary around the cell-substrate adhered area on the plasma membrane. We show that the contact perimeter guides PIP3 waves and acts as a pinning site of PIP3 phase singularities, that is, the center point of spiral waves. The contact perimeter serves as a diffusion influencing boundary that is regulated by a cell size- and shape-dependent curvature. Our findings suggest an underlying mechanism that explains how local curvature can favor actin polymerization when PIP3 domains get pinned at the curved protrusive membrane edges in amoeboid cells.
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Affiliation(s)
- Marcel Hörning
- Institute of Biomaterials and Biomolecular Systems, University of Stuttgart, Stuttgart, Germany.,Laboratory for Physical Biology, RIKEN Center for Biosystems Dynamics Research, Kobe, Japan
| | - Torsten Bullmann
- Carl-Ludwig-Institute for Physiology, University of Leipzig, Leipzig, Germany
| | - Tatsuo Shibata
- Laboratory for Physical Biology, RIKEN Center for Biosystems Dynamics Research, Kobe, Japan
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7
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McNeely KC, Dwyer ND. Cytokinetic Abscission Regulation in Neural Stem Cells and Tissue Development. CURRENT STEM CELL REPORTS 2021; 7:161-173. [PMID: 36303610 PMCID: PMC9603694 DOI: 10.1007/s40778-021-00193-7] [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: 11/20/2022]
Abstract
Purpose of Review How stem cells balance proliferation with differentiation, giving rise to specific daughter cells during development to build an embryo or tissue, remains an open question. Here, we discuss recent evidence that cytokinetic abscission regulation in stem cells, particularly neural stem cells (NSCs), is part of the answer. Abscission is a multi-step process mediated by the midbody, a microtubule-based structure formed in the intercellular bridge between daughter cells after mitosis. Recent Findings Human mutations and mouse knockouts in abscission genes reveal that subtle disruptions of NSC abscission can cause brain malformations. Experiments in several epithelial systems have shown that midbodies serve as scaffolds for apical junction proteins and are positioned near apical membrane fate determinants. Abscission timing is tightly controlled and developmentally regulated in stem cells, with delayed abscission in early embryos and faster abscission later. Midbody remnants (MBRs) contain over 400 proteins and may influence polarity, fate, and ciliogenesis. Summary As NSCs and other stem cells build tissues, they tightly regulate three aspects of abscission: midbody positioning, duration, and MBR handling. Midbody positioning and remnants establish or maintain cell polarity. MBRs are deposited on the apical membranes of epithelia, can be released or internalized by surrounding cells, and may sequester fate determinants or transfer information between cells. Work in cell lines and simpler systems has shown multiple roles for abscission regulation influencing stem cell polarity, potency, and daughter fates during development. Elucidating how the abscission process influences cell fate and tissue growth is important for our continued understanding of brain development and stem cell biology.
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8
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Pino MR, Nuñez I, Chen C, Das ME, Wiley DJ, D'Urso G, Buchwald P, Vavylonis D, Verde F. Cdc42 GTPase Activating Proteins (GAPs) Regulate Generational Inheritance of Cell Polarity and Cell Shape in Fission Yeast. Mol Biol Cell 2021; 32:ar14. [PMID: 34288736 PMCID: PMC8684747 DOI: 10.1091/mbc.e20-10-0666] [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: 11/11/2022] Open
Abstract
The highly conserved small GTPase Cdc42 regulates polarized cell growth and morphogenesis from yeast to humans. We previously reported that Cdc42 activation exhibits oscillatory dynamics at cell tips of Schizosaccharomyces pombe cells. Mathematical modeling suggests that this dynamic behavior enables a variety of symmetric and asymmetric Cdc42 activation distributions to coexist in cell populations. For individual wild-type cells, however, Cdc42 distribution is initially asymmetrical and becomes more symmetrical as cell volume increases, enabling bipolar growth activation. To explore whether different patterns of Cdc42 activation are possible in vivo, we examined S. pombe rga4∆ mutant cells, lacking the Cdc42 GTPase-activating protein (GAP) Rga4. We found that monopolar rga4∆ mother cells divide asymmetrically leading to the emergence of both symmetric and asymmetric Cdc42 distributions in rga4∆ daughter cells. Motivated by different hypotheses that can mathematically reproduce the unequal fate of daughter cells, we used genetic screening to identify mutants that alter the rga4∆ phenotype. We found that the unequal distribution of active Cdc42 GTPase is consistent with an unequal inheritance of another Cdc42 GAP, Rga6, in the two daughter cells. Our findings highlight the crucial role of Cdc42 GAP localization in maintaining consistent Cdc42 activation and growth patterns across generations.
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Affiliation(s)
- Marbelys Rodriguez Pino
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL 33101-1015, USA.,Current Address: Department of Biology, Health & Wellness, Miami Dade College, Miami, FL 33176
| | - Illyce Nuñez
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL 33101-1015, USA
| | - Chuan Chen
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL 33101-1015, USA
| | - Maitreyi E Das
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL 33101-1015, USA.,Current Address: Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996
| | - David J Wiley
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL 33101-1015, USA
| | - Gennaro D'Urso
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL 33101-1015, USA
| | - Peter Buchwald
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL 33101-1015, USA
| | - Dimitrios Vavylonis
- Department of Physics, Lehigh University, 16 Memorial Drive East, Bethlehem, PA, 18015
| | - Fulvia Verde
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL 33101-1015, USA
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9
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Watchaputi K, Somboon P, Phromma-in N, Ratanakhanokchai K, Soontorngun N. Actin cytoskeletal inhibitor 19,20-epoxycytochalasin Q sensitizes yeast cells lacking ERG6 through actin-targeting and secondarily through disruption of lipid homeostasis. Sci Rep 2021; 11:7779. [PMID: 33833332 PMCID: PMC8032726 DOI: 10.1038/s41598-021-87342-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Accepted: 03/22/2021] [Indexed: 02/01/2023] Open
Abstract
Repetitive uses of antifungals result in a worldwide crisis of drug resistance; therefore, natural fungicides with minimal side-effects are currently sought after. This study aimed to investigate antifungal property of 19, 20-epoxycytochalasin Q (ECQ), derived from medicinal mushroom Xylaria sp. BCC 1067 of tropical forests. In a model yeast Saccharomyces cerevisiae, ECQ is more toxic in the erg6∆ strain, which has previously been shown to allow higher uptake of many hydrophilic toxins. We selected one pathway to study the effects of ECQ at very high levels on transcription: the ergosterol biosynthesis pathway, which is unlikely to be the primary target of ECQ. Ergosterol serves many functions that cholesterol does in human cells. ECQ's transcriptional effects were correlated with altered sterol and triacylglycerol levels. In the ECQ-treated Δerg6 strain, which presumably takes up far more ECQ than the wild-type strain, there was cell rupture. Increased actin aggregation and lipid droplets assembly were also found in the erg6∆ mutant. Thereby, ECQ is suggested to sensitize yeast cells lacking ERG6 through actin-targeting and consequently but not primarily led to disruption of lipid homeostasis. Investigation of cytochalasins may provide valuable insight with potential biopharmaceutical applications in treatments of fungal infection, cancer or metabolic disorder.
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Affiliation(s)
- Kwanrutai Watchaputi
- grid.412151.20000 0000 8921 9789Division of Biochemical Technology, School of Bioresources and Technology, King Mongkut’s University of Technology Thonburi (KMUTT), Bangkok, 10150 Thailand
| | - Pichayada Somboon
- grid.419784.70000 0001 0816 7508Division of Fermentation Technology, Faculty of Food Industry, King Mongkut’s Institute of Technology Ladkrabang (KMITL), Bangkok, 10520 Thailand
| | - Nipatthra Phromma-in
- grid.412151.20000 0000 8921 9789Division of Biochemical Technology, School of Bioresources and Technology, King Mongkut’s University of Technology Thonburi (KMUTT), Bangkok, 10150 Thailand
| | - Khanok Ratanakhanokchai
- grid.412151.20000 0000 8921 9789Division of Biochemical Technology, School of Bioresources and Technology, King Mongkut’s University of Technology Thonburi (KMUTT), Bangkok, 10150 Thailand
| | - Nitnipa Soontorngun
- grid.412151.20000 0000 8921 9789Division of Biochemical Technology, School of Bioresources and Technology, King Mongkut’s University of Technology Thonburi (KMUTT), Bangkok, 10150 Thailand
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10
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Mamula D, Korthals M, Hradsky J, Gottfried A, Fischer KD, Tedford K. Arhgef6 (alpha-PIX) cytoskeletal regulator signals to GTPases and Cofilin to couple T cell migration speed and persistence. J Leukoc Biol 2021; 110:839-852. [PMID: 33527537 DOI: 10.1002/jlb.1a1219-719r] [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: 12/15/2019] [Revised: 12/10/2020] [Accepted: 01/08/2021] [Indexed: 11/11/2022] Open
Abstract
Immunity is governed by successful T cell migration, optimized to enable a T cell to fully scan its environment without wasted movement by balancing speed and turning. Here we report that the Arhgef6 RhoGEF (aka alpha-PIX; αPIX; Cool-2), an activator of small GTPases, is required to restrain cell migration speed and cell turning during spontaneous migration on 2D surfaces. In Arhgef6-/- T cells, expression of Arhgef7 (beta-PIX; βPIX; Cool-1), a homolog of Arhgef6, was increased and correlated with defective activation and localization of Rac1 and CDC42 GTPases, respectively. Downstream of Arhgef6, PAK2 (p21-activated kinase 2) and LIMK1 phosphorylation was reduced, leading to increased activation of Cofilin, the actin-severing factor. Consistent with defects in these signaling pathways, Arhgef6-/- T cells displayed abnormal bilobed lamellipodia and migrated faster, turned more, and arrested less than wild-type (WT) T cells. Using pharmacologic inhibition of LIMK1 (LIM domain kinase 1) to induce Cofilin activation in WT T cells, we observed increased migration speed but not increased cell turning. In contrast, inhibition of Cdc42 increased cell turning but not speed. These results suggested that the increased speed of the Arhgef6-/- T cells is due to hyperactive Cofilin while the increased turning may be due to abnormal GTPase activation and recruitment. Together, these findings reveal that Arhgef6 acts as a repressor of T cell speed and turning by limiting actin polymerization and lamellipodia formation.
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Affiliation(s)
- Dejan Mamula
- Institute for Biochemistry and Cell Biology, Otto-von-Guericke University Magdeburg, Magdeburg, Germany.,Present address: Department of Clinical Neuroscience, Karolinska Institute, Stockholm, Sweden
| | - Mark Korthals
- Institute for Biochemistry and Cell Biology, Otto-von-Guericke University Magdeburg, Magdeburg, Germany
| | - Johannes Hradsky
- Institute for Biochemistry and Cell Biology, Otto-von-Guericke University Magdeburg, Magdeburg, Germany
| | - Anna Gottfried
- Institute for Biochemistry and Cell Biology, Otto-von-Guericke University Magdeburg, Magdeburg, Germany
| | - Klaus-Dieter Fischer
- Institute for Biochemistry and Cell Biology, Otto-von-Guericke University Magdeburg, Magdeburg, Germany.,Center for Cellular Imaging and Innovative Disease Models, Medical Faculty, Otto-von-Guericke University Magdeburg, Magdeburg, Germany
| | - Kerry Tedford
- Institute for Biochemistry and Cell Biology, Otto-von-Guericke University Magdeburg, Magdeburg, Germany.,Center for Cellular Imaging and Innovative Disease Models, Medical Faculty, Otto-von-Guericke University Magdeburg, Magdeburg, Germany
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11
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Rivera-Robles MJ, Medina-Velázquez J, Asencio-Torres GM, González-Crespo S, Rymond BC, Rodríguez-Medina J, Dharmawardhane S. Targeting Cdc42 with the anticancer compound MBQ-167 inhibits cell polarity and growth in the budding yeast S. cerevisiae. Small GTPases 2020; 11:430-440. [PMID: 29969362 PMCID: PMC7549613 DOI: 10.1080/21541248.2018.1495008] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
Abstract
The Rho GTPase Cdc42 is highly conserved in structure and function. Mechanical or chemical cues in the microenvironment stimulate the localized activation of Cdc42 to rearrange the actin cytoskeleton and establish cell polarity. A role for Cdc42 in cell polarization was first discovered in the budding yeast Saccharomyces cerevisiae, and subsequently shown to also regulate directional motility in animal cells. Accordingly, in cancer Cdc42 promotes migration, invasion, and spread of tumor cells. Therefore, we targeted Cdc42 as a therapeutic strategy to treat metastatic breast cancer and designed the small molecule MBQ-167 as a potent inhibitor against Cdc42 and the homolog Rac. MBQ-167 inhibited cancer cell proliferation and migration in-vitro, and tumor growth and spread in-vivo in a mouse xenograft model of metastatic breast cancer. Since haploid budding yeast express a single Cdc42 gene, and do not express Rac, we used this well characterized model of polarization to define the contribution of Cdc42 inhibition to the effects of MBQ-167 in eukaryotic cells. Growth, budding pattern, and Cdc42 activity was determined in wildtype yeast or cells expressing a conditional knockdown of Cdc42 in response to vehicle or MBQ-167 treatment. As expected, growth and budding polarity were reduced by knocking-down Cdc42, with a parallel effect observed with MBQ-167. Cdc42 activity assays confirmed that MBQ-167 inhibits Cdc42 activation in yeast, and thus, bud polarity. Hence, we have validated MBQ-167 as a Cdc42 inhibitor in another biological context and present a method to screen Cdc42 inhibitors with potential as anti-metastatic cancer drugs.
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Affiliation(s)
- Michael John Rivera-Robles
- Department of Biochemistry, School of Medicine, University of Puerto Rico Medical Sciences Campus, San Juan, USA
| | - Julia Medina-Velázquez
- Department of Biochemistry, School of Medicine, University of Puerto Rico Medical Sciences Campus, San Juan, USA
| | - Gabriela M. Asencio-Torres
- Department of Biochemistry, School of Medicine, University of Puerto Rico Medical Sciences Campus, San Juan, USA
| | - Sahily González-Crespo
- Department of Biochemistry, School of Medicine, University of Puerto Rico Medical Sciences Campus, San Juan, USA
| | - Brian C. Rymond
- Department of Biology, University of Kentucky, Lexington, USA
| | - José Rodríguez-Medina
- Department of Biochemistry, School of Medicine, University of Puerto Rico Medical Sciences Campus, San Juan, USA
| | - Suranganie Dharmawardhane
- Department of Biochemistry, School of Medicine, University of Puerto Rico Medical Sciences Campus, San Juan, USA
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12
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Abstract
The Rho GTPase Cdc42 is a central regulator of cell polarity in diverse cell types. The activity of Cdc42 is dynamically controlled in time and space to enable distinct polarization events, which generally occur along a single axis in response to spatial cues. Our understanding of the mechanisms underlying Cdc42 polarization has benefited largely from studies of the budding yeast Saccharomyces cerevisiae, a genetically tractable model organism. In budding yeast, Cdc42 activation occurs in two temporal steps in the G1 phase of the cell cycle to establish a proper growth site. Here, we review findings in budding yeast that reveal an intricate crosstalk among polarity proteins for biphasic Cdc42 regulation. The first step of Cdc42 activation may determine the axis of cell polarity, while the second step ensures robust Cdc42 polarization for growth. Biphasic Cdc42 polarization is likely to ensure the proper timing of events including the assembly and recognition of spatial landmarks and stepwise assembly of a new ring of septins, cytoskeletal GTP-binding proteins, at the incipient bud site. Biphasic activation of GTPases has also been observed in mammalian cells, suggesting that biphasic activation could be a general mechanism for signal-responsive cell polarization. Cdc42 activity is necessary for polarity establishment during normal cell division and development, but its activity has also been implicated in the promotion of aging. We also discuss negative polarity signaling and emerging concepts of Cdc42 signaling in cellular aging.
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Affiliation(s)
- Kristi E Miller
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210.,Present address: Department of Biochemistry and Cell Biology, The Geisel School of Medicine at Dartmouth, Hanover, NH 03755
| | - Pil Jung Kang
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210
| | - Hay-Oak Park
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210
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13
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Aguilar-Aragon M, Fletcher G, Thompson BJ. The cytoskeletal motor proteins Dynein and MyoV direct apical transport of Crumbs. Dev Biol 2020; 459:126-137. [PMID: 31881198 PMCID: PMC7090908 DOI: 10.1016/j.ydbio.2019.12.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Revised: 12/17/2019] [Accepted: 12/17/2019] [Indexed: 12/12/2022]
Abstract
Crumbs (Crb in Drosophila; CRB1-3 in mammals) is a transmembrane determinant of epithelial cell polarity and a regulator of Hippo signalling. Crb is normally localized to apical cell-cell contacts, just above adherens junctions, but how apical trafficking of Crb is regulated in epithelial cells remains unclear. We use the Drosophila follicular epithelium to demonstrate that polarized trafficking of Crb is mediated by transport along microtubules by the motor protein Dynein and along actin filaments by the motor protein Myosin-V (MyoV). Blocking transport of Crb-containing vesicles by Dynein or MyoV leads to accumulation of Crb within Rab11 endosomes, rather than apical delivery. The final steps of Crb delivery and stabilisation at the plasma membrane requires the exocyst complex and three apical FERM domain proteins - Merlin, Moesin and Expanded - whose simultaneous loss disrupts apical localization of Crb. Accordingly, a knock-in deletion of the Crb FERM-binding motif (FBM) also impairs apical localization. Finally, overexpression of Crb challenges this system, creating a sensitized background to identify components involved in cytoskeletal polarization, apical membrane trafficking and stabilisation of Crb at the apical domain.
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Affiliation(s)
- M Aguilar-Aragon
- The Francis Crick Institute, 1 Midland Rd, NW1 1AT, London, United Kingdom
| | - G Fletcher
- The Francis Crick Institute, 1 Midland Rd, NW1 1AT, London, United Kingdom
| | - B J Thompson
- The Francis Crick Institute, 1 Midland Rd, NW1 1AT, London, United Kingdom; The John Curtin School of Medical Research, The Australian National University, 131 Garran Rd, Acton, ACT 2601, Canberra, Australia.
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14
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Hercyk BS, Rich-Robinson J, Mitoubsi AS, Harrell MA, Das ME. A novel interplay between GEFs orchestrates Cdc42 activity during cell polarity and cytokinesis in fission yeast. J Cell Sci 2019; 132:jcs.236018. [PMID: 31719163 DOI: 10.1242/jcs.229252/video-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 11/04/2019] [Indexed: 05/23/2023] Open
Abstract
Cdc42, a conserved regulator of cell polarity, is activated by two GEFs, Gef1 and Scd1, in fission yeast. Why the cell needs two GEFs is unclear, given that they are partially redundant and activate the same GTPase. Using the GEF localization pattern during cytokinesis as a paradigm, we report a novel interplay between Gef1 and Scd1 that spatially modulates Cdc42. We find that Gef1 promotes Scd1 localization to the division site during cytokinesis through recruitment of the scaffold protein Scd2, via a Cdc42 feedforward pathway. Similarly, during interphase Gef1 promotes Scd1 recruitment at the new end to enable the transition from monopolar to bipolar growth. Reciprocally, Scd1 restricts Gef1 localization to prevent ectopic Cdc42 activation during cytokinesis to promote cell separation, and to maintain cell shape during interphase. Our findings reveal an elegant regulatory pattern in which Gef1 primes Cdc42 activation at new sites to initiate Scd1-dependent polarized growth, while Scd1 restricts Gef1 to sites of polarization. We propose that crosstalk between GEFs is a conserved mechanism that orchestrates Cdc42 activation during complex cellular processes.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Brian S Hercyk
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 7996-1939, USA
| | - Julie Rich-Robinson
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 7996-1939, USA
| | - Ahmad S Mitoubsi
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 7996-1939, USA
| | - Marcus A Harrell
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 7996-1939, USA
| | - Maitreyi E Das
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 7996-1939, USA
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15
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Hercyk BS, Rich-Robinson J, Mitoubsi AS, Harrell MA, Das ME. A novel interplay between GEFs orchestrates Cdc42 activity during cell polarity and cytokinesis in fission yeast. J Cell Sci 2019; 132:jcs.236018. [PMID: 31719163 DOI: 10.1242/jcs.236018] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 11/04/2019] [Indexed: 12/12/2022] Open
Abstract
Cdc42, a conserved regulator of cell polarity, is activated by two GEFs, Gef1 and Scd1, in fission yeast. Why the cell needs two GEFs is unclear, given that they are partially redundant and activate the same GTPase. Using the GEF localization pattern during cytokinesis as a paradigm, we report a novel interplay between Gef1 and Scd1 that spatially modulates Cdc42. We find that Gef1 promotes Scd1 localization to the division site during cytokinesis through recruitment of the scaffold protein Scd2, via a Cdc42 feedforward pathway. Similarly, during interphase Gef1 promotes Scd1 recruitment at the new end to enable the transition from monopolar to bipolar growth. Reciprocally, Scd1 restricts Gef1 localization to prevent ectopic Cdc42 activation during cytokinesis to promote cell separation, and to maintain cell shape during interphase. Our findings reveal an elegant regulatory pattern in which Gef1 primes Cdc42 activation at new sites to initiate Scd1-dependent polarized growth, while Scd1 restricts Gef1 to sites of polarization. We propose that crosstalk between GEFs is a conserved mechanism that orchestrates Cdc42 activation during complex cellular processes.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Brian S Hercyk
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 7996-1939, USA
| | - Julie Rich-Robinson
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 7996-1939, USA
| | - Ahmad S Mitoubsi
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 7996-1939, USA
| | - Marcus A Harrell
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 7996-1939, USA
| | - Maitreyi E Das
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 7996-1939, USA
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16
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Cao Y, Ghabache E, Rappel WJ. Plasticity of cell migration resulting from mechanochemical coupling. eLife 2019; 8:e48478. [PMID: 31625907 PMCID: PMC6799977 DOI: 10.7554/elife.48478] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 10/02/2019] [Indexed: 01/07/2023] Open
Abstract
Eukaryotic cells can migrate using different modes, ranging from amoeboid-like, during which actin filled protrusions come and go, to keratocyte-like, characterized by a stable morphology and persistent motion. How cells can switch between these modes is not well understood but waves of signaling events are thought to play an important role in these transitions. Here we present a simple two-component biochemical reaction-diffusion model based on relaxation oscillators and couple this to a model for the mechanics of cell deformations. Different migration modes, including amoeboid-like and keratocyte-like, naturally emerge through transitions determined by interactions between biochemical traveling waves, cell mechanics and morphology. The model predictions are explicitly verified by systematically reducing the protrusive force of the actin network in experiments using Dictyostelium discoideum cells. Our results indicate the importance of coupling signaling events to cell mechanics and morphology and may be applicable in a wide variety of cell motility systems.
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Affiliation(s)
- Yuansheng Cao
- Department of PhysicsUniversity of California, San DiegoLa JollaUnited States
| | - Elisabeth Ghabache
- Department of PhysicsUniversity of California, San DiegoLa JollaUnited States
| | - Wouter-Jan Rappel
- Department of PhysicsUniversity of California, San DiegoLa JollaUnited States
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17
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Altenburg T, Goldenbogen B, Uhlendorf J, Klipp E. Osmolyte homeostasis controls single-cell growth rate and maximum cell size of Saccharomyces cerevisiae. NPJ Syst Biol Appl 2019; 5:34. [PMID: 31583116 PMCID: PMC6763471 DOI: 10.1038/s41540-019-0111-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Accepted: 08/23/2019] [Indexed: 11/09/2022] Open
Abstract
Cell growth is well described at the population level, but precisely how nutrient and water uptake and cell wall expansion drive the growth of single cells is poorly understood. Supported by measurements of single-cell growth trajectories and cell wall elasticity, we present a single-cell growth model for yeast. The model links the thermodynamic quantities, such as turgor pressure, osmolarity, cell wall elasto-plasticity, and cell size, applying concepts from rheology and thin shell theory. It reproduces cell size dynamics during single-cell growth, budding, and hyper-osmotic or hypo-osmotic stress. We find that single-cell growth rate and final size are primarily governed by osmolyte uptake and consumption, while bud expansion requires additionally different cell wall extensibilities between mother and bud. Based on first principles the model provides a more accurate description of size dynamics than previous attempts and its analytical simplification allows for easy combination with models for other cell processes.
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Affiliation(s)
- Tom Altenburg
- Theoretical Biophysics, Humboldt-Universität zu Berlin, Berlin, Germany
- Robert Koch-Institut, Berlin, Germany
| | - Björn Goldenbogen
- Theoretical Biophysics, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Jannis Uhlendorf
- Theoretical Biophysics, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Edda Klipp
- Theoretical Biophysics, Humboldt-Universität zu Berlin, Berlin, Germany
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18
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Sharma J, Rosiana S, Razzaq I, Shapiro RS. Linking Cellular Morphogenesis with Antifungal Treatment and Susceptibility in Candida Pathogens. J Fungi (Basel) 2019; 5:E17. [PMID: 30795580 PMCID: PMC6463059 DOI: 10.3390/jof5010017] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 02/11/2019] [Accepted: 02/13/2019] [Indexed: 02/07/2023] Open
Abstract
Fungal infections are a growing public health concern, and an increasingly important cause of human mortality, with Candida species being amongst the most frequently encountered of these opportunistic fungal pathogens. Several Candida species are polymorphic, and able to transition between distinct morphological states, including yeast, hyphal, and pseudohyphal forms. While not all Candida pathogens are polymorphic, the ability to undergo morphogenesis is linked with the virulence of many of these pathogens. There are also many connections between Candida morphogenesis and antifungal drug treatment and susceptibility. Here, we review how Candida morphogenesis-a key virulence trait-is linked with antifungal drugs and antifungal drug resistance. We highlight how antifungal therapeutics are able to modulate morphogenesis in both sensitive and drug-resistant Candida strains, the shared signaling pathways that mediate both morphogenesis and the cellular response to antifungal drugs and drug resistance, and the connection between Candida morphology, drug resistance, and biofilm growth. We further review the development of anti-virulence drugs, and targeting Candida morphogenesis as a novel therapeutic strategy to target fungal pathogens. Together, this review highlights important connections between fungal morphogenesis, virulence, and susceptibility to antifungals.
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Affiliation(s)
- Jehoshua Sharma
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1G 2W1, Canada.
| | - Sierra Rosiana
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1G 2W1, Canada.
| | - Iqra Razzaq
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1G 2W1, Canada.
| | - Rebecca S Shapiro
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1G 2W1, Canada.
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19
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Comparison of Deterministic and Stochastic Regime in a Model for Cdc42 Oscillations in Fission Yeast. Bull Math Biol 2019; 81:1268-1302. [PMID: 30756233 DOI: 10.1007/s11538-019-00573-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 01/29/2019] [Indexed: 01/13/2023]
Abstract
Oscillations occur in a wide variety of essential cellular processes, such as cell cycle progression, circadian clocks and calcium signaling in response to stimuli. It remains unclear how intrinsic stochasticity can influence these oscillatory systems. Here, we focus on oscillations of Cdc42 GTPase in fission yeast. We extend our previous deterministic model by Xu and Jilkine to construct a stochastic model, focusing on the fast diffusion case. We use SSA (Gillespie's algorithm) to numerically explore the low copy number regime in this model, and use analytical techniques to study the long-time behavior of the stochastic model and compare it to the equilibria of its deterministic counterpart. Numerical solutions suggest noisy limit cycles exist in the parameter regime in which the deterministic system converges to a stable limit cycle, and quasi-cycles exist in the parameter regime where the deterministic model has a damped oscillation. Near an infinite period bifurcation point, the deterministic model has a sustained oscillation, while stochastic trajectories start with an oscillatory mode and tend to approach deterministic steady states. In the low copy number regime, metastable transitions from oscillatory to steady behavior occur in the stochastic model. Our work contributes to the understanding of how stochastic chemical kinetics can affect a finite-dimensional dynamical system, and destabilize a deterministic steady state leading to oscillations.
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20
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Vendel KJA, Tschirpke S, Shamsi F, Dogterom M, Laan L. Minimal in vitro systems shed light on cell polarity. J Cell Sci 2019; 132:132/4/jcs217554. [PMID: 30700498 DOI: 10.1242/jcs.217554] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Cell polarity - the morphological and functional differentiation of cellular compartments in a directional manner - is required for processes such as orientation of cell division, directed cellular growth and motility. How the interplay of components within the complexity of a cell leads to cell polarity is still heavily debated. In this Review, we focus on one specific aspect of cell polarity: the non-uniform accumulation of proteins on the cell membrane. In cells, this is achieved through reaction-diffusion and/or cytoskeleton-based mechanisms. In reaction-diffusion systems, components are transformed into each other by chemical reactions and are moving through space by diffusion. In cytoskeleton-based processes, cellular components (i.e. proteins) are actively transported by microtubules (MTs) and actin filaments to specific locations in the cell. We examine how minimal systems - in vitro reconstitutions of a particular cellular function with a minimal number of components - are designed, how they contribute to our understanding of cell polarity (i.e. protein accumulation), and how they complement in vivo investigations. We start by discussing the Min protein system from Escherichia coli, which represents a reaction-diffusion system with a well-established minimal system. This is followed by a discussion of MT-based directed transport for cell polarity markers as an example of a cytoskeleton-based mechanism. To conclude, we discuss, as an example, the interplay of reaction-diffusion and cytoskeleton-based mechanisms during polarity establishment in budding yeast.
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Affiliation(s)
- Kim J A Vendel
- Bionanoscience Department, Kavli Institute of Nanoscience, Delft University of Technology, Delft 2600 GA, The Netherlands
| | - Sophie Tschirpke
- Bionanoscience Department, Kavli Institute of Nanoscience, Delft University of Technology, Delft 2600 GA, The Netherlands
| | - Fayezeh Shamsi
- Bionanoscience Department, Kavli Institute of Nanoscience, Delft University of Technology, Delft 2600 GA, The Netherlands
| | - Marileen Dogterom
- Bionanoscience Department, Kavli Institute of Nanoscience, Delft University of Technology, Delft 2600 GA, The Netherlands
| | - Liedewij Laan
- Bionanoscience Department, Kavli Institute of Nanoscience, Delft University of Technology, Delft 2600 GA, The Netherlands
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21
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Hörning M, Shibata T. Three-Dimensional Cell Geometry Controls Excitable Membrane Signaling in Dictyostelium Cells. Biophys J 2019; 116:372-382. [PMID: 30635124 PMCID: PMC6350023 DOI: 10.1016/j.bpj.2018.12.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 11/16/2018] [Accepted: 12/13/2018] [Indexed: 01/13/2023] Open
Abstract
Phosphatidylinositol (3-5)-trisphosphate (PtdInsP3) is known to propagate as waves on the plasma membrane and is related to the membrane-protrusive activities in Dictyostelium and mammalian cells. Although there have been a few attempts to study the three-dimensional (3D) dynamics of these processes, most studies have focused on the dynamics extracted from single focal planes. However, the relation between the dynamics and 3D cell shape remains elusive because of the lack of signaling information about the unobserved part of the membrane. Here, we show that PtdInsP3 wave dynamics are directly regulated by the 3D geometry (i.e., size and shape) of the plasma membrane. By introducing an analysis method that extracts the 3D spatiotemporal activities on the entire cell membrane, we show that PtdInsP3 waves self-regulate their dynamics within the confined membrane area. This leads to changes in speed, orientation, and pattern evolution, following the underlying excitability of the signal transduction system. Our findings emphasize the role of the plasma membrane topology in reaction-diffusion-driven biological systems and indicate its importance in other mammalian systems.
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Affiliation(s)
- Marcel Hörning
- Laboratory for Physical Biology, RIKEN Center for Biosystems Dynamics Research, Kobe, Japan; Institute of Biomaterials and Biomolecular Systems, University of Stuttgart, Stuttgart, Germany; Institute for Integrated Cell-Material Sciences, Kyoto University, Kyoto, Japan.
| | - Tatsuo Shibata
- Laboratory for Physical Biology, RIKEN Center for Biosystems Dynamics Research, Kobe, Japan.
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22
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Vogel D, Dussutour A, Deneubourg JL. Symmetry breaking and inter-clonal behavioural variability in a slime mould. Biol Lett 2018; 14:20180504. [PMID: 30958252 PMCID: PMC6303507 DOI: 10.1098/rsbl.2018.0504] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 11/16/2018] [Indexed: 11/12/2022] Open
Abstract
Cells are dynamic systems capable of switching from isotropic growth to polarized growth even in the absence of any pre-existing external asymmetry. Here, we study this process of symmetry breaking in the acellular slime mould Physarum polycephalum. In these experiments, slime moulds could grow on two identical opposed sources of calcium. We highlighted a positive correlation between growth dynamic, level of symmetry breaking and calcium concentration. We identified three populations of slime moulds within our clonal lineage with similar symmetry breaking behaviours but different motility characteristics. These behavioural differences between slime moulds emerged in the absence of any environmental differences. Such behavioural plasticity could generate cellular diversity, which can be critical for survival.
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Affiliation(s)
- David Vogel
- Research Centre on Animal Cognition (CRCA), Centre for Integrative Biology (CBI), Toulouse University, CNRS, UPS, 31062 Toulouse, France
- School of Agriculture, Food and Wine (AFW), University of Adelaide, Adelaide, Australia
| | - Audrey Dussutour
- Research Centre on Animal Cognition (CRCA), Centre for Integrative Biology (CBI), Toulouse University, CNRS, UPS, 31062 Toulouse, France
| | - Jean-Louis Deneubourg
- Chemical Physics and Theoretical Biology (CPTB), Université Libre de Bruxelles, 1050 Bruxelles, Belgium
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23
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Khalili B, Merlini L, Vincenzetti V, Martin SG, Vavylonis D. Exploration and stabilization of Ras1 mating zone: A mechanism with positive and negative feedbacks. PLoS Comput Biol 2018; 14:e1006317. [PMID: 30028833 PMCID: PMC6070293 DOI: 10.1371/journal.pcbi.1006317] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Revised: 08/01/2018] [Accepted: 06/21/2018] [Indexed: 02/07/2023] Open
Abstract
In mating fission yeast cells, sensing and response to extracellular pheromone concentrations occurs through an exploratory Cdc42 patch that stochastically samples the cell cortex before stabilizing towards a mating partner. Active Ras1 (Ras1-GTP), an upstream regulator of Cdc42, and Gap1, the GTPase-activating protein for Ras1, localize at the patch. We developed a reaction-diffusion model of Ras1 patch appearance and disappearance with a positive feedback by a Guanine nucleotide Exchange Factor (GEF) and Gap1 inhibition. The model is based on new estimates of Ras1-GDP, Ras1-GTP and Gap1 diffusion coefficients and rates of cytoplasmic exchange studied by FRAP. The model reproduces exploratory patch behavior and lack of Ras1 patch in cells lacking Gap1. Transition to a stable patch can occur by change of Gap1 rates constants or local increase of the positive feedback rate constants. The model predicts that the patch size and number of patches depend on the strength of positive and negative feedbacks. Measurements of Ras1 patch size and number in cells overexpressing the Ras1 GEF or Gap1 are consistent with the model. Unicellular fission yeasts mate by fusing with partners of the opposite mating type. Each pair member grows towards its selected partner that signals its presence through secreted pheromone. The process of partner selection occurs through an exploratory patch (containing activated signaling protein Cdc42 and upstream regulator Ras1) that assembles and disassembles on the cell cortex, stabilizing in regions of higher opposite pheromone concentration. We present a computational model of the molecular mechanisms driving the dynamical pattern of patch exploration and stabilization. The model is based on reaction and diffusion along the curved cell membrane, with diffusion coefficients measured experimentally. In the model, a positive Ras1 activation feedback loop generates a patch containing most of the activating protein (Ras1 GEF). The fast diffusing inhibitor Gap1 that is recruited locally from the cytoplasm spreads on the cell membrane, limiting patch size and causing its decay. Spontaneous reinitiation of Ras1 activation elsewhere on the cortex provides a mechanism for exploration. Transition of the system’s behavior to that of a single stable patch is possible upon simulated pheromone sensing. The computational model provides predictions for the number of patches and patch size dependence on parameters that we tested experimentally.
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Affiliation(s)
- Bita Khalili
- Department of Physics, Lehigh University, Bethlehem, Pennsylvania, United States of America
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Laura Merlini
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Vincent Vincenzetti
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Sophie G. Martin
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Dimitrios Vavylonis
- Department of Physics, Lehigh University, Bethlehem, Pennsylvania, United States of America
- * E-mail:
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24
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Song Y, Michaels TCT, Ma Q, Liu Z, Yuan H, Takayama S, Knowles TPJ, Shum HC. Budding-like division of all-aqueous emulsion droplets modulated by networks of protein nanofibrils. Nat Commun 2018; 9:2110. [PMID: 29844310 PMCID: PMC5974351 DOI: 10.1038/s41467-018-04510-3] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Accepted: 04/30/2018] [Indexed: 01/01/2023] Open
Abstract
Networks of natural protein nanofibrils, such as cytoskeletal filaments, control the shape and the division of cells, yet mimicking this functionality in a synthetic setting has proved challenging. Here, we demonstrate that artificial networks of protein nanofibrils can induce controlled deformation and division of all-aqueous emulsion droplets with budding-like morphologies. We show that this process is driven by the difference in the immersional wetting energy of the nanofibril network, and that both the size and the number of the daughter droplets formed during division can be controlled by modulating the fibril concentration and the chemical properties of the fibril network. Our results demonstrate a route for achieving biomimetic division with synthetic self-assembling fibrils and offer an engineered approach to regulate the morphology of protein gels.
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Affiliation(s)
- Yang Song
- Department of Mechanical Engineering, The University of Hong Kong, Pokfulam, 999077, Hong Kong
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Thomas C T Michaels
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK
- Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, 02138, USA
| | - Qingming Ma
- Department of Mechanical Engineering, The University of Hong Kong, Pokfulam, 999077, Hong Kong
- HKU-Shenzhen Institute of Research and Innovation (HKU-SIRI), 518000, Shenzhen, China
| | - Zhou Liu
- Department of Mechanical Engineering, The University of Hong Kong, Pokfulam, 999077, Hong Kong
- HKU-Shenzhen Institute of Research and Innovation (HKU-SIRI), 518000, Shenzhen, China
| | - Hao Yuan
- Department of Mechanical Engineering, The University of Hong Kong, Pokfulam, 999077, Hong Kong
- HKU-Shenzhen Institute of Research and Innovation (HKU-SIRI), 518000, Shenzhen, China
| | - Shuichi Takayama
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Tuomas P J Knowles
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK
- Cavendish Laboratory, Department of Physics, University of Cambridge, JJ Thomson Avenue, Cambridge, CB3 0HE, UK
| | - Ho Cheung Shum
- Department of Mechanical Engineering, The University of Hong Kong, Pokfulam, 999077, Hong Kong.
- HKU-Shenzhen Institute of Research and Innovation (HKU-SIRI), 518000, Shenzhen, China.
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25
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Pablo M, Ramirez SA, Elston TC. Particle-based simulations of polarity establishment reveal stochastic promotion of Turing pattern formation. PLoS Comput Biol 2018. [PMID: 29529021 PMCID: PMC5864077 DOI: 10.1371/journal.pcbi.1006016] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Polarity establishment, the spontaneous generation of asymmetric molecular distributions, is a crucial component of many cellular functions. Saccharomyces cerevisiae (yeast) undergoes directed growth during budding and mating, and is an ideal model organism for studying polarization. In yeast and many other cell types, the Rho GTPase Cdc42 is the key molecular player in polarity establishment. During yeast polarization, multiple patches of Cdc42 initially form, then resolve into a single front. Because polarization relies on strong positive feedback, it is likely that the amplification of molecular-level fluctuations underlies the generation of multiple nascent patches. In the absence of spatial cues, these fluctuations may be key to driving polarization. Here we used particle-based simulations to investigate the role of stochastic effects in a Turing-type model of yeast polarity establishment. In the model, reactions take place either between two molecules on the membrane, or between a cytosolic and a membrane-bound molecule. Thus, we developed a computational platform that explicitly simulates molecules at and near the cell membrane, and implicitly handles molecules away from the membrane. To evaluate stochastic effects, we compared particle simulations to deterministic reaction-diffusion equation simulations. Defining macroscopic rate constants that are consistent with the microscopic parameters for this system is challenging, because diffusion occurs in two dimensions and particles exchange between the membrane and cytoplasm. We address this problem by empirically estimating macroscopic rate constants from appropriately designed particle-based simulations. Ultimately, we find that stochastic fluctuations speed polarity establishment and permit polarization in parameter regions predicted to be Turing stable. These effects can operate at Cdc42 abundances expected of yeast cells, and promote polarization on timescales consistent with experimental results. To our knowledge, our work represents the first particle-based simulations of a model for yeast polarization that is based on a Turing mechanism. Many cells need to generate and maintain biochemical signals in specific subcellular regions. This phenomenon is broadly called polarity establishment, and is important in fundamental processes such as cell migration and differentiation. A key polarity factor found in diverse organisms, including yeast and humans, is the protein Cdc42. In yeast, Cdc42-dependent polarization occurs through a self-reinforcing biochemical signaling loop. Directional cues can guide polarity establishment, but interestingly, yeast can polarize in the absence of such a cue. The mechanism thought to underlie this symmetry breaking involves the amplification of inhomogeneities in molecular distributions that arise from molecular-level fluctuations. We investigated the effects of random fluctuations on polarization by performing particle-based simulations of the Cdc42 signaling network. We found that fluctuations can facilitate polarization, allowing faster polarization, and polarization over a broader range of concentrations. Our observations may help understand how polarity works in other systems.
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Affiliation(s)
- Michael Pablo
- Department of Chemistry, The University of North Carolina, Chapel Hill, NC, United States of America
- Program in Molecular and Cellular Biophysics, The University of North Carolina, Chapel Hill, NC, United States of America
| | - Samuel A. Ramirez
- Department of Pharmacology, The University of North Carolina, Chapel Hill, NC, United States of America
| | - Timothy C. Elston
- Department of Pharmacology, The University of North Carolina, Chapel Hill, NC, United States of America
- * E-mail:
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26
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Segal D, Zaritsky A, Schejter ED, Shilo BZ. Feedback inhibition of actin on Rho mediates content release from large secretory vesicles. J Cell Biol 2018; 217:1815-1826. [PMID: 29496739 PMCID: PMC5940311 DOI: 10.1083/jcb.201711006] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 12/24/2017] [Accepted: 01/30/2018] [Indexed: 12/02/2022] Open
Abstract
This work identified a cycle of actin assembly and disassembly in large secretory vesicles of Drosophila salivary glands. Actin disassembly is triggered by actin-dependent recruitment of a RhoGAP protein and is essential for the contractility of the vesicle, leading to content release to the lumen. Secretion of adhesive glycoproteins to the lumen of Drosophila melanogaster larval salivary glands is performed by contraction of an actomyosin network assembled around large secretory vesicles, after their fusion to the apical membranes. We have identified a cycle of actin coat nucleation and disassembly that is independent of myosin. Recruitment of active Rho1 to the fused vesicle triggers activation of the formin Diaphanous and actin nucleation. This leads to actin-dependent localization of a RhoGAP protein that locally shuts off Rho1, promoting disassembly of the actin coat. When contraction of vesicles is blocked, the strict temporal order of the recruited elements generates repeated oscillations of actin coat formation and disassembly. Interestingly, different blocks to actin coat disassembly arrested vesicle contraction, indicating that actin turnover is an integral part of the actomyosin contraction cycle. The capacity of F-actin to trigger a negative feedback on its own production may be widely used to coordinate a succession of morphogenetic events or maintain homeostasis.
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Affiliation(s)
- Dagan Segal
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Assaf Zaritsky
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel.,Lyda Hill Department of Bioinformatics, University of Texas Southwestern Medical Center, Dallas, TX
| | - Eyal D Schejter
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Ben-Zion Shilo
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
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27
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Merlini L, Khalili B, Dudin O, Michon L, Vincenzetti V, Martin SG. Inhibition of Ras activity coordinates cell fusion with cell-cell contact during yeast mating. J Cell Biol 2018; 217:1467-1483. [PMID: 29453312 PMCID: PMC5881505 DOI: 10.1083/jcb.201708195] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 01/08/2018] [Accepted: 01/24/2018] [Indexed: 02/07/2023] Open
Abstract
In the fission yeast Schizosaccharomyces pombe, pheromone signaling engages a signaling pathway composed of a G protein-coupled receptor, Ras, and a mitogen-activated protein kinase (MAPK) cascade that triggers sexual differentiation and gamete fusion. Cell-cell fusion requires local cell wall digestion, which relies on an initially dynamic actin fusion focus that becomes stabilized upon local enrichment of the signaling cascade on the structure. We constructed a live-reporter of active Ras1 (Ras1-guanosine triphosphate [GTP]) that shows Ras activity at polarity sites peaking on the fusion structure before fusion. Remarkably, constitutive Ras1 activation promoted fusion focus stabilization and fusion attempts irrespective of cell pairing, leading to cell lysis. Ras1 activity was restricted by the guanosine triphosphatase-activating protein Gap1, which was itself recruited to sites of Ras1-GTP and was essential to block untimely fusion attempts. We propose that negative feedback control of Ras activity restrains the MAPK signal and couples fusion with cell-cell engagement.
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Affiliation(s)
- Laura Merlini
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Bita Khalili
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland.,Department of Physics, Lehigh University, Bethlehem, PA
| | - Omaya Dudin
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Laetitia Michon
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Vincent Vincenzetti
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Sophie G Martin
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
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28
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Abstract
Polarized exocytosis is generally considered as the multistep vesicular trafficking process in which membrane-bounded carriers are transported from the Golgi or endosomal compartments to specific sites of the plasma membrane. Polarized exocytosis in cells is achieved through the coordinated actions of membrane trafficking machinery and cytoskeleton orchestrated by signaling molecules such as the Rho family of small GTPases. Elucidating the molecular mechanisms of polarized exocytosis is essential to our understanding of a wide range of pathophysiological processes from neuronal development to tumor invasion.
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Affiliation(s)
- Jingwen Zeng
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6018
| | - Shanshan Feng
- Key Laboratory for Regenerative Medicine of Ministry of Education and Department of Developmental & Regenerative Biology, Jinan University, Guangzhou 510632, P.R. China
| | - Bin Wu
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6018
| | - Wei Guo
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6018
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29
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Wang Y, Lo WC, Chou CS. A modeling study of budding yeast colony formation and its relationship to budding pattern and aging. PLoS Comput Biol 2017; 13:e1005843. [PMID: 29121651 PMCID: PMC5697893 DOI: 10.1371/journal.pcbi.1005843] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 11/21/2017] [Accepted: 10/20/2017] [Indexed: 11/23/2022] Open
Abstract
Budding yeast, which undergoes polarized growth during budding and mating, has been a useful model system to study cell polarization. Bud sites are selected differently in haploid and diploid yeast cells: haploid cells bud in an axial manner, while diploid cells bud in a bipolar manner. While previous studies have been focused on the molecular details of the bud site selection and polarity establishment, not much is known about how different budding patterns give rise to different functions at the population level. In this paper, we develop a two-dimensional agent-based model to study budding yeast colonies with cell-type specific biological processes, such as budding, mating, mating type switch, consumption of nutrients, and cell death. The model demonstrates that the axial budding pattern enhances mating probability at an early stage and the bipolar budding pattern improves colony development under nutrient limitation. Our results suggest that the frequency of mating type switch might control the trade-off between diploidization and inbreeding. The effect of cellular aging is also studied through our model. Based on the simulations, colonies initiated by an aged haploid cell show declined mating probability at an early stage and recover as the rejuvenated offsprings become the majority. Colonies initiated with aged diploid cells do not show disadvantage in colony expansion possibly due to the fact that young cells contribute the most to colony expansion. Budding yeast is a model organism in understanding fundamental aspects of eukaryotic cells, such as cell polarization and cell aging. Previously, extensive research has focused on the molecular mechanisms of biological processes in yeast, but many questions regarding yeast budding remain unsolved. For example, how do different budding patterns affect yeast colony growth? How does declined spatial order due to aging impact the colony at the population level? To address these questions, we developed a computational agent-based model, which incorporates key biological processes, the effect of aging, as well as cell-environment interaction. We performed and analyzed a large number of simulations for a variety of situations, and obtained insightful results. We found that axial budding pattern enhances the percentage of diploid cells at early stage and bipolar budding pattern improves colony development under nutrient limitation; the frequency of mating type switch might control the trade-off between diploidization and inbreeding; aging affects the percentage of diploid cells in colonies initiated by a single haploid cell, but does not have much influence in the expansion of colonies initiated by diploid cells. The framework of the model can be extended to study other important systems, such as tissue with stem cell lineage.
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Affiliation(s)
- Yanli Wang
- Department of Mathematics, The Ohio State University, Columbus, Ohio, United States of America
| | - Wing-Cheong Lo
- Department of Mathematics, City University of Hong Kong, Hong Kong, China
| | - Ching-Shan Chou
- Department of Mathematics, The Ohio State University, Columbus, Ohio, United States of America
- * E-mail:
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30
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Hegemann B, Peter M. Local sampling paints a global picture: Local concentration measurements sense direction in complex chemical gradients. Bioessays 2017; 39. [PMID: 28556309 DOI: 10.1002/bies.201600134] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Detecting and interpreting extracellular spatial signals is essential for cellular orientation within complex environments, such as during directed cell migration or growth in multicellular development. Although the molecular understanding of how cells read spatial signals like chemical gradients is still lacking, recent work has revealed that stochastic processes at different temporal and spatial scales are at the core of this gradient sensing process in a wide range of eukaryotes. Fast biochemical reactions like those underlying GTPase activity dynamics form a functional module together with slower cell morphological changes driven by membrane remodelling. This biochemical-morphological module explores the environment by stochastic local concentration sampling to determine the source of the gradient signal, enabling efficient signal detection and interpretation before polarised growth or migration towards the gradient source is initiated. Here we review recent data describing local sampling and propose a model of local fast and slow feedback counteracted by gradient-dependent substrate limitation to be at the core of gradient sensing by local sampling.
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Affiliation(s)
- Björn Hegemann
- Department of Biology, Institute of Biochemistry, ETH Zurich, Zürich, Switzerland
| | - Matthias Peter
- Department of Biology, Institute of Biochemistry, ETH Zurich, Zürich, Switzerland
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31
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Von Stetina SE, Liang J, Marnellos G, Mango SE. Temporal regulation of epithelium formation mediated by FoxA, MKLP1, MgcRacGAP, and PAR-6. Mol Biol Cell 2017; 28:2042-2065. [PMID: 28539408 PMCID: PMC5509419 DOI: 10.1091/mbc.e16-09-0644] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Revised: 05/18/2017] [Accepted: 05/18/2017] [Indexed: 12/15/2022] Open
Abstract
During embryo morphogenesis, minor epithelia are generated after, and then form bridges between, major epithelia (e.g., epidermis and gut). In Caenorhabditis elegans, this delay is regulated by four proteins that control production and localization of polarity proteins: the pioneer factor PHA-4/FoxA, kinesin ZEN-4/MKLP1, its partner CYK-4/MgcRacGAP, and PAR-6. To establish the animal body plan, embryos link the external epidermis to the internal digestive tract. In Caenorhabditis elegans, this linkage is achieved by the arcade cells, which form an epithelial bridge between the foregut and epidermis, but little is known about how development of these three epithelia is coordinated temporally. The arcade cell epithelium is generated after the epidermis and digestive tract epithelia have matured, ensuring that both organs can withstand the mechanical stress of embryo elongation; mistiming of epithelium formation leads to defects in morphogenesis. Using a combination of genetic, bioinformatic, and imaging approaches, we find that temporal regulation of the arcade cell epithelium is mediated by the pioneer transcription factor and master regulator PHA-4/FoxA, followed by the cytoskeletal regulator and kinesin ZEN-4/MKLP1 and the polarity protein PAR-6. We show that PHA-4 directly activates mRNA expression of a broad cohort of epithelial genes, including junctional factor dlg-1. Accumulation of DLG-1 protein is delayed by ZEN-4, acting in concert with its binding partner CYK-4/MgcRacGAP. Our structure–function analysis suggests that nuclear and kinesin functions are dispensable, whereas binding to CYK-4 is essential, for ZEN-4 function in polarity. Finally, PAR-6 is necessary to localize polarity proteins such as DLG-1 within adherens junctions and at the apical surface, thereby generating arcade cell polarity. Our results reveal that the timing of a landmark event during embryonic morphogenesis is mediated by the concerted action of four proteins that delay the formation of an epithelial bridge until the appropriate time. In addition, we find that mammalian FoxA associates with many epithelial genes, suggesting that direct regulation of epithelial identity may be a conserved feature of FoxA factors and a contributor to FoxA function in development and cancer.
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Affiliation(s)
- Stephen E Von Stetina
- Department of Molecular and Cellular Biology, Harvard University, Cambridge; MA 02138
| | - Jennifer Liang
- Department of Molecular and Cellular Biology, Harvard University, Cambridge; MA 02138
| | - Georgios Marnellos
- Informatics and Scientific Applications, Science Division, Faculty of Arts and Sciences, Harvard University, Cambridge; MA 02138
| | - Susan E Mango
- Department of Molecular and Cellular Biology, Harvard University, Cambridge; MA 02138
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32
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Zhang Y, Guo X, Dong J. Phosphorylation of the Polarity Protein BASL Differentiates Asymmetric Cell Fate through MAPKs and SPCH. Curr Biol 2016; 26:2957-2965. [PMID: 27746029 DOI: 10.1016/j.cub.2016.08.066] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Revised: 08/03/2016] [Accepted: 08/30/2016] [Indexed: 12/27/2022]
Abstract
Cell polarization is commonly used for the regulation of stem cell asymmetric division in both animals and plants. Stomatal development in Arabidopsis, a process that produces breathing pores in the epidermis, requires asymmetric cell division to differentiate highly specialized guard cells while maintaining a stem cell population [1, 2]. The BREAKING OF ASYMMETRY IN THE STOMATAL LINEAGE (BASL) protein exhibits a polarized localization pattern in the cell and is required for differential cell fates resulting from asymmetric cell division [3]. The polarization of BASL is made possible by a positive feedback loop with a canonical mitogen-activated protein kinase (MAPK) pathway that recruits the MAPKK kinase YODA (YDA) and MAPK 6 (MPK6) to the cortical polarity site [4]. Here, we study BASL intracellular dynamics and show that the membrane-associated BASL is slowly replenished at the cortical polarity site and that the mobility is tightly linked to its phosphorylation status. Because BASL polarity is only exhibited by one daughter cell after an asymmetric cell division, we study how BASL differentially functions in the two daughter cells. The YDA MAPK cascade transduces upstream ligand-receptor signaling [5-13] to the transcription factor SPEECHLESS (SPCH), which controls stomatal initiation and is directly suppressed by MPK3/6-mediated phosphorylation [14, 15]. We show that BASL polarization leads to elevated nuclear MPK6 signaling and lowered SPCH abundance in one of the two daughter cells. Therefore, two daughter cells are differentiated by BASL polarity-mediated differential suppression of SPCH, which may provide developmental plasticity in plant stem cell asymmetric cell division (ACD).
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Affiliation(s)
- Ying Zhang
- Waksman Institute of Microbiology, Rutgers, the State University of New Jersey, Piscataway, NJ 08854, USA
| | - Xiaoyu Guo
- Waksman Institute of Microbiology, Rutgers, the State University of New Jersey, Piscataway, NJ 08854, USA
| | - Juan Dong
- Waksman Institute of Microbiology, Rutgers, the State University of New Jersey, Piscataway, NJ 08854, USA; Department of Plant Biology and Pathology, Rutgers, the State University of New Jersey, Piscataway, NJ 08901, USA.
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33
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Visco I, Hoege C, Hyman AA, Schwille P. In vitro Reconstitution of a Membrane Switch Mechanism for the Polarity Protein LGL. J Mol Biol 2016; 428:4828-4842. [PMID: 27720986 DOI: 10.1016/j.jmb.2016.10.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Revised: 09/28/2016] [Accepted: 10/01/2016] [Indexed: 12/24/2022]
Abstract
Cell polarity arises from a combination of interactions between biological molecules, such as activation, inhibition, and positive or negative feedback between specific polarity units. Activation and inhibition often take place in the form of a membrane binding switch. Lethal giant larvae (LGL), a conserved regulator of cell polarity in animals, was suggested to function as such a switch. LGL localizes to both the cytoplasm and, asymmetrically, the membrane. However, the spatial regulation mechanism of LGL membrane localization has remained unclear. For systematic elucidation, we set out to reconstitute a minimal polarity unit using a model membrane, Caenorhabditis elegans LGL (LGL-1), and atypical protein kinase C (aPKC) supposed to activate the membrane switch. We identified a membrane binding sequence (MBS) in LGL-1 by a screen in vivo, reconstituted LGL-1 membrane binding in vitro, and successfully implemented the membrane switch by aPKC phosphorylation activity, detaching LGL from membranes. Upon membrane binding, LGL-1 MBS folds into an alpha-helix in which three regions can be identified: a positively charged patch, a switch area containing the three aPKC phosphorylation sites, and a hydrophobic area probably buried in the membrane. Phosphorylation by aPKC dramatically reduces the binding affinity of the LGL-1 MBS to negatively charged model membranes, inducing its detachment. Specific residues in the MBS are critical for LGL-1 function in C. elegans.
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Affiliation(s)
- Ilaria Visco
- Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany.
| | - Carsten Hoege
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
| | - Anthony A Hyman
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
| | - Petra Schwille
- Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany.
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34
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Nishikawa T, Motter AE. Symmetric States Requiring System Asymmetry. PHYSICAL REVIEW LETTERS 2016; 117:114101. [PMID: 27661690 DOI: 10.1103/physrevlett.117.114101] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Indexed: 06/06/2023]
Abstract
Spontaneous synchronization has long served as a paradigm for behavioral uniformity that can emerge from interactions in complex systems. When the interacting entities are identical and their coupling patterns are also identical, the complete synchronization of the entire network is the state inheriting the system symmetry. As in other systems subject to symmetry breaking, such symmetric states are not always stable. Here, we report on the discovery of the converse of symmetry breaking-the scenario in which complete synchronization is not stable for identically coupled identical oscillators but becomes stable when, and only when, the oscillator parameters are judiciously tuned to nonidentical values, thereby breaking the system symmetry to preserve the state symmetry. Aside from demonstrating that diversity can facilitate and even be required for uniformity and consensus, this suggests a mechanism for convergent forms of pattern formation in which initially asymmetric patterns evolve into symmetric ones.
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Affiliation(s)
- Takashi Nishikawa
- Department of Physics and Astronomy, Northwestern University, Evanston, Illinois 60208, USA and Northwestern Institute on Complex Systems, Northwestern University, Evanston, Illinois 60208, USA
| | - Adilson E Motter
- Department of Physics and Astronomy, Northwestern University, Evanston, Illinois 60208, USA and Northwestern Institute on Complex Systems, Northwestern University, Evanston, Illinois 60208, USA
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35
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Zhang Y, Bergmann DC, Dong J. Fine-scale dissection of the subdomains of polarity protein BASL in stomatal asymmetric cell division. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:5093-103. [PMID: 27422992 PMCID: PMC5014157 DOI: 10.1093/jxb/erw274] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Cell polarity is a prerequisite for asymmetric cell divisions (ACDs) that generate cell type diversity during development of multicellular organisms. In Arabidopsis, stomatal lineage ACDs are regulated by the plant-specific protein BREAKING OF ASYMMETRY IN THE STOMATAL LINEAGE (BASL). BASL exhibits dynamic subcellular localization, accumulating initially in the nucleus, but then additionally in a highly polarized crescent at the cell cortex before division. BASL polarization requires a phosphorylation-mediated activation process, but how this is achieved remains unknown. In this study, we performed a fine-scale dissection of BASL protein subdomains and elucidated a nuclear localization sequence for nuclear import and a critical FxFP motif for cortical polarity formation, respectively. Artificially tethering BASL subdomains to the plasma membrane suggests that novel protein partner/s might exist and bind to an internal region of BASL. In addition, we suspect the existence of a protein degradation mechanism associated with the amino terminal domain of BASL that accounts for restricting its predominant expression to the stomatal lineage cells of the epidermis. Taken together, our results revealed that BASL, through its distinct subdomains, integrates multiple regulatory inputs to provide a mechanism that promotes difference during stomatal lineage ACDs.
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Affiliation(s)
- Ying Zhang
- Waksman Institute of Microbiology, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Dominique C Bergmann
- Department of Biology, 371 Serra Mall, Stanford University, Stanford, CA 94305-5020, USA HHMI, Stanford University, Stanford, CA 94305-5020, USA
| | - Juan Dong
- Waksman Institute of Microbiology, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA Department of Biology, 371 Serra Mall, Stanford University, Stanford, CA 94305-5020, USA Department of Plant Biology and Pathology, Rutgers, The State University of New Jersey, Piscataway, NJ 08901, USA
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36
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Shao W, Dong J. Polarity in plant asymmetric cell division: Division orientation and cell fate differentiation. Dev Biol 2016; 419:121-131. [PMID: 27475487 DOI: 10.1016/j.ydbio.2016.07.020] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2016] [Revised: 07/18/2016] [Accepted: 07/26/2016] [Indexed: 01/04/2023]
Abstract
Asymmetric cell division (ACD) is universally required for the development of multicellular organisms. Unlike animal cells, plant cells have a rigid cellulosic extracellular matrix, the cell wall, which provides physical support and forms communication routes. This fundamental difference leads to some unique mechanisms in plants for generating asymmetries during cell division. However, plants also utilize intrinsically polarized proteins to regulate asymmetric signaling and cell division, a strategy similar to the differentiation mechanism found in animals. Current progress suggests that common regulatory modes, i.e. protein spontaneous clustering and cytoskeleton reorganization, underlie protein polarization in both animal and plant cells. Despite these commonalities, it is important to note that intrinsic mechanisms in plants are heavily influenced by extrinsic cues. To control physical asymmetry in cell division, although our understanding is fragmentary thus far, plants might have evolved novel polarization strategies to orientate cell division plane. Recent studies also suggest that the phytohormone auxin, one of the most pivotal small molecules in plant development, regulates ACD in plants.
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Affiliation(s)
- Wanchen Shao
- Department of Plant Biology and Pathology, Rutgers the State University of New Jersey, NJ 08901, USA
| | - Juan Dong
- Department of Plant Biology and Pathology, Rutgers the State University of New Jersey, NJ 08901, USA; Waksman Institute of Microbiology, Rutgers the State University of New Jersey, NJ 08854, USA.
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37
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Muller N, Piel M, Calvez V, Voituriez R, Gonçalves-Sá J, Guo CL, Jiang X, Murray A, Meunier N. A Predictive Model for Yeast Cell Polarization in Pheromone Gradients. PLoS Comput Biol 2016; 12:e1004795. [PMID: 27077831 PMCID: PMC4831791 DOI: 10.1371/journal.pcbi.1004795] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Accepted: 02/08/2016] [Indexed: 11/18/2022] Open
Abstract
Budding yeast cells exist in two mating types, a and α, which use peptide pheromones to communicate with each other during mating. Mating depends on the ability of cells to polarize up pheromone gradients, but cells also respond to spatially uniform fields of pheromone by polarizing along a single axis. We used quantitative measurements of the response of a cells to α-factor to produce a predictive model of yeast polarization towards a pheromone gradient. We found that cells make a sharp transition between budding cycles and mating induced polarization and that they detect pheromone gradients accurately only over a narrow range of pheromone concentrations corresponding to this transition. We fit all the parameters of the mathematical model by using quantitative data on spontaneous polarization in uniform pheromone concentration. Once these parameters have been computed, and without any further fit, our model quantitatively predicts the yeast cell response to pheromone gradient providing an important step toward understanding how cells communicate with each other.
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Affiliation(s)
- Nicolas Muller
- MAP5, CNRS UMR 8145, Université Paris Descartes, Paris, France
| | - Matthieu Piel
- Institut Curie, CNRS UMR 144, Paris, France
- * E-mail: (MP); (AM); (NM)
| | - Vincent Calvez
- Unité de Mathématiques Pures et Appliquées, CNRS UMR 5669 and équipe-projet INRIA NUMED, École Normale Supérieure de Lyon, Lyon, France
| | - Raphaël Voituriez
- Laboratoire Jean Perrin and Laboratoire de Physique Théorique de la Matière Condensée, UMR 7600 CNRS /UPMC, Paris, France
| | - Joana Gonçalves-Sá
- Molecular and Cell Biology and FAS Center for Systems Biology, Harvard University, Cambridge, Massachusetts, United States of America
| | - Chin-Lin Guo
- Molecular and Cell Biology and FAS Center for Systems Biology, Harvard University, Cambridge, Massachusetts, United States of America
- Institute of Physics, Academia Sinica, Taiwan
| | - Xingyu Jiang
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, United States of America
- CAS Key Laboratory for Biological Effects of Nanomaterials and Nanosafety, National Center for Nanoscience and Technology, Beijing, People’s Republic of China
| | - Andrew Murray
- Molecular and Cell Biology and FAS Center for Systems Biology, Harvard University, Cambridge, Massachusetts, United States of America
- * E-mail: (MP); (AM); (NM)
| | - Nicolas Meunier
- MAP5, CNRS UMR 8145, Université Paris Descartes, Paris, France
- * E-mail: (MP); (AM); (NM)
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38
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Abstract
Evolution of budding yeast after the removal of an important component of the polarization machinery, BEM1, followed reproducible evolutionary trajectories governed by epistasis. Interestingly, cells restored polarization not by finding a substitute for Bem1 but by rendering its function dispensable.
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Affiliation(s)
- Gaowen Liu
- Institute of Medical Biology (IMB), Agency for Science, Technology and Research (A(∗)STAR), Singapore 138648, Singapore; School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Giulia Rancati
- Institute of Medical Biology (IMB), Agency for Science, Technology and Research (A(∗)STAR), Singapore 138648, Singapore.
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39
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Sarto-Jackson I, Tomaska L. How to bake a brain: yeast as a model neuron. Curr Genet 2016; 62:347-70. [PMID: 26782173 DOI: 10.1007/s00294-015-0554-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 12/09/2015] [Accepted: 12/10/2015] [Indexed: 12/14/2022]
Abstract
More than 30 years ago Dan Koshland published an inspirational essay presenting the bacterium as a model neuron (Koshland, Trends Neurosci 6:133-137, 1983). In the article he argued that there are several similarities between neurons and bacterial cells in "how signals are processed within a cell or how this processing machinery can be modified to produce plasticity". He then explored the bacterial chemosensory system to emphasize its attributes that are analogous to information processing in neurons. In this review, we wish to expand Koshland's original idea by adding the yeast cell to the list of useful models of a neuron. The fact that yeasts and neurons are specialized versions of the eukaryotic cell sharing all principal components sets the stage for a grand evolutionary tinkering where these components are employed in qualitatively different tasks, but following analogous molecular logic. By way of example, we argue that evolutionarily conserved key components involved in polarization processes (from budding or mating in Saccharomyces cervisiae to neurite outgrowth or spinogenesis in neurons) are shared between yeast and neurons. This orthologous conservation of modules makes S. cervisiae an excellent model organism to investigate neurobiological questions. We substantiate this claim by providing examples of yeast models used for studying neurological diseases.
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Affiliation(s)
- Isabella Sarto-Jackson
- Konrad Lorenz Institute for Evolution and Cognition Research, Martinstraße 12, 3400, Klosterneuburg, Austria.
| | - Lubomir Tomaska
- Department of Genetics, Faculty of Natural Sciences, Comenius University in Bratislava, Mlynska dolina B-1, Ilkovicova 6, 842 15, Bratislava, Slovak Republic.
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40
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Mao Q, Lecuit T. Mechanochemical Interplay Drives Polarization in Cellular and Developmental Systems. Curr Top Dev Biol 2016; 116:633-57. [DOI: 10.1016/bs.ctdb.2015.11.039] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
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41
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Bruurs LJM, Donker L, Zwakenberg S, Zwartkruis FJ, Begthel H, Knisely AS, Posthuma G, van de Graaf SFJ, Paulusma CC, Bos JL. ATP8B1-mediated spatial organization of Cdc42 signaling maintains singularity during enterocyte polarization. J Cell Biol 2015; 210:1055-63. [PMID: 26416959 PMCID: PMC4586737 DOI: 10.1083/jcb.201505118] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
The disease-associated phospholipid flippase ATP8B1 decreases Cdc42 mobility at the apical membrane to ensure the formation of a single apical domain and to maintain healthy lumen architecture. During yeast cell polarization localization of the small GTPase, cell division control protein 42 homologue (Cdc42) is clustered to ensure the formation of a single bud. Here we show that the disease-associated flippase ATPase class I type 8b member 1 (ATP8B1) enables Cdc42 clustering during enterocyte polarization. Loss of this regulation results in increased apical membrane size with scattered apical recycling endosomes and permits the formation of more than one apical domain, resembling the singularity defect observed in yeast. Mechanistically, we show that to become apically clustered, Cdc42 requires the interaction between its polybasic region and negatively charged membrane lipids provided by ATP8B1. Disturbing this interaction, either by ATP8B1 depletion or by introduction of a Cdc42 mutant defective in lipid binding, increases Cdc42 mobility and results in apical membrane enlargement. Re-establishing Cdc42 clustering, by tethering it to the apical membrane or lowering its diffusion, restores normal apical membrane size in ATP8B1-depleted cells. We therefore conclude that singularity regulation by Cdc42 is conserved between yeast and human and that this regulation is required to maintain healthy tissue architecture.
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Affiliation(s)
- Lucas J M Bruurs
- Molecular Cancer Research and Cancer Genomics Netherlands, Center for Molecular Medicine, University Medical Center Utrecht, 3584 CG Utrecht, Netherlands
| | - Lisa Donker
- Molecular Cancer Research and Cancer Genomics Netherlands, Center for Molecular Medicine, University Medical Center Utrecht, 3584 CG Utrecht, Netherlands
| | - Susan Zwakenberg
- Molecular Cancer Research and Cancer Genomics Netherlands, Center for Molecular Medicine, University Medical Center Utrecht, 3584 CG Utrecht, Netherlands
| | - Fried J Zwartkruis
- Molecular Cancer Research and Cancer Genomics Netherlands, Center for Molecular Medicine, University Medical Center Utrecht, 3584 CG Utrecht, Netherlands
| | - Harry Begthel
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences (KNAW) and University Medical Center Utrecht, 3508 AD Utrecht, Netherlands
| | - A S Knisely
- Institute of Liver Studies, King's College Hospital, London SE5 9RS, England, UK
| | - George Posthuma
- Department of Cell Biology, Center for Molecular Medicine, University Medical Center Utrecht, 3584 CG Utrecht, Netherlands
| | - Stan F J van de Graaf
- Tytgat Institute for Liver and Intestinal Research, Academic Medical Centre, 1105 AZ Amsterdam, Netherlands
| | - Coen C Paulusma
- Tytgat Institute for Liver and Intestinal Research, Academic Medical Centre, 1105 AZ Amsterdam, Netherlands
| | - Johannes L Bos
- Molecular Cancer Research and Cancer Genomics Netherlands, Center for Molecular Medicine, University Medical Center Utrecht, 3584 CG Utrecht, Netherlands
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Kamiyama D, McGorty R, Kamiyama R, Kim MD, Chiba A, Huang B. Specification of Dendritogenesis Site in Drosophila aCC Motoneuron by Membrane Enrichment of Pak1 through Dscam1. Dev Cell 2015; 35:93-106. [PMID: 26460947 PMCID: PMC4626010 DOI: 10.1016/j.devcel.2015.09.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Revised: 07/07/2015] [Accepted: 09/11/2015] [Indexed: 01/11/2023]
Abstract
Precise positioning of dendritic branches is a critical step in the establishment of neuronal circuitry. However, there is limited knowledge on how environmental cues translate into dendrite initiation or branching at a specific position. Here, through a combination of mutation, RNAi, and imaging experiments, we found that a Dscam-Dock-Pak1 hierarchical interaction defines the stereotypical dendrite growth site in the Drosophila aCC motoneuron. This interaction localizes the Cdc42 effector Pak1 to the plasma membrane at the dendrite initiation site before the activation of Cdc42. Ectopic expression of membrane-anchored Pak1 overrides this spatial specification of dendritogenesis, confirming its function in guiding Cdc42 signaling. We further discovered that Dscam1 localization in aCC occurs through an inter-neuronal contact that involves Dscam1 in the partner MP1 neuron. These findings elucidate a mechanism by which Dscam1 controls neuronal morphogenesis through spatial regulation of Cdc42 signaling and, subsequently, cytoskeletal remodeling.
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MESH Headings
- Adaptor Proteins, Signal Transducing/genetics
- Adaptor Proteins, Signal Transducing/metabolism
- Animals
- Animals, Genetically Modified/genetics
- Animals, Genetically Modified/growth & development
- Animals, Genetically Modified/metabolism
- Cell Adhesion Molecules
- Cell Differentiation
- Cell Membrane/metabolism
- Cells, Cultured
- Cytoskeleton/metabolism
- Dendrites/physiology
- Drosophila/genetics
- Drosophila/growth & development
- Drosophila/metabolism
- Drosophila Proteins/antagonists & inhibitors
- Drosophila Proteins/genetics
- Drosophila Proteins/metabolism
- Embryo, Nonmammalian/cytology
- Embryo, Nonmammalian/metabolism
- GTP-Binding Proteins/genetics
- GTP-Binding Proteins/metabolism
- Gene Expression Regulation, Developmental
- Immunoenzyme Techniques
- Interneurons/cytology
- Interneurons/metabolism
- Morphogenesis/physiology
- Motor Neurons/cytology
- Motor Neurons/metabolism
- Nerve Tissue Proteins/genetics
- Nerve Tissue Proteins/metabolism
- Neural Cell Adhesion Molecules/antagonists & inhibitors
- Neural Cell Adhesion Molecules/genetics
- Neural Cell Adhesion Molecules/metabolism
- RNA, Small Interfering/genetics
- p21-Activated Kinases/genetics
- p21-Activated Kinases/metabolism
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Affiliation(s)
- Daichi Kamiyama
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA 94158, USA.
| | - Ryan McGorty
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Rie Kamiyama
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Michael D Kim
- Miami Institute of Molecular Imaging and Computation, Coral Gables, FL 33146, USA; Department of Molecular and Cellular Pharmacology, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | - Akira Chiba
- Department of Biology, University of Miami, Coral Gables, FL 33146, USA; Miami Institute of Molecular Imaging and Computation, Coral Gables, FL 33146, USA
| | - Bo Huang
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA 94158, USA; Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA.
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Laan L, Koschwanez JH, Murray AW. Evolutionary adaptation after crippling cell polarization follows reproducible trajectories. eLife 2015; 4. [PMID: 26426479 PMCID: PMC4630673 DOI: 10.7554/elife.09638] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 09/30/2015] [Indexed: 12/21/2022] Open
Abstract
Cells are organized by functional modules, which typically contain components whose removal severely compromises the module's function. Despite their importance, these components are not absolutely conserved between parts of the tree of life, suggesting that cells can evolve to perform the same biological functions with different proteins. We evolved Saccharomyces cerevisiae for 1000 generations without the important polarity gene BEM1. Initially the bem1∆ lineages rapidly increase in fitness and then slowly reach >90% of the fitness of their BEM1 ancestors at the end of the evolution. Sequencing their genomes and monitoring polarization reveals a common evolutionary trajectory, with a fixed sequence of adaptive mutations, each improving cell polarization by inactivating proteins. Our results show that organisms can be evolutionarily robust to physiologically destructive perturbations and suggest that recovery by gene inactivation can lead to rapid divergence in the parts list for cell biologically important functions. DOI:http://dx.doi.org/10.7554/eLife.09638.001 Cells use the genetic instructions provided by genes in particular combinations called ‘modules’ to perform particular jobs. Very different organisms can share many of the same modules because certain abilities are fundamental to the survival of all cells and so they have been retained over the course of evolution. That said, these modules may not necessarily involve the same genes because it is often possible to achieve the same result using different components. One way to study how those modules can diversify is to deliberately disrupt one of the genes in a module, and observe how the organism and its descendants respond over many generations. Other genes in these organisms may acquire genetic mutations that enable the genes to take on the role of the missing protein. However, the removal of a single component can be detrimental to the survival of the organisms or may affect many different processes. This can make it difficult to understand what is going on. A gene called BEM1 is crucial for yeast cells to establish polarity, that is, to allow the different sides of a cell to become distinct from one another. This activity is essential for the yeast to replicate itself. Previous studies have shown that the BEM1 gene had a different role in other species of fungi, which suggests that yeast may have other genes that previously assumed the role that BEM1 does now. In this study, Laan et al. removed BEM1 from yeast and allowed the population of mutant cells to evolve for a thousand generations. The approach differs from previous studies because Laan et al. deliberately selected for yeast that had acquired multiple genetic mutations that can together almost fully compensate for the loss of BEM1. Initially, the mutant cells grew very slowly, were abnormal in shape and likely to burst open. However, by the end of the experiment, the cells were able to grow almost as well as the original yeast cells had before the gene deletion. Genetic analysis revealed that the deletion of BEM1 triggers the inactivation of other genes that are also involved in the regulation of polarity, which largely restored the ability of the disrupted polarity module to work. This restoration follows a ‘reproducible trajectory’, as the same genes were switched off in the same order in different populations of yeast that were studied at the same time. The work is an example of reproducible evolution, whereby a specific order of changes to gene activity repeatedly enables cells with severe defects in important processes to adapt and restore a gene module, using whatever components they have left. The next challenge will be to understand how the particular roles of important modules affect their adaptability. DOI:http://dx.doi.org/10.7554/eLife.09638.002
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Affiliation(s)
- Liedewij Laan
- FAS Center for Systems Biology, Department of Molecular and Cellular Biology, Harvard University, Cambridge, United States
| | - John H Koschwanez
- FAS Center for Systems Biology, Department of Molecular and Cellular Biology, Harvard University, Cambridge, United States
| | - Andrew W Murray
- FAS Center for Systems Biology, Department of Molecular and Cellular Biology, Harvard University, Cambridge, United States
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Das M, Nuñez I, Rodriguez M, Wiley DJ, Rodriguez J, Sarkeshik A, Yates JR, Buchwald P, Verde F. Phosphorylation-dependent inhibition of Cdc42 GEF Gef1 by 14-3-3 protein Rad24 spatially regulates Cdc42 GTPase activity and oscillatory dynamics during cell morphogenesis. Mol Biol Cell 2015; 26:3520-34. [PMID: 26246599 PMCID: PMC4591695 DOI: 10.1091/mbc.e15-02-0095] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Accepted: 07/30/2015] [Indexed: 11/25/2022] Open
Abstract
The 14-3-3 protein Rad24 modulates the availability of Cdc42 GEF Gef1, spatially regulating Cdc42 activity during cell morphogenesis. Gef1 is sequestered in the cytoplasm upon 14-3-3 interaction, mediated by Orb6 kinase. The resulting competition for Gef1 promotes anticorrelated Cdc42 oscillations at cell tips. Active Cdc42 GTPase, a key regulator of cell polarity, displays oscillatory dynamics that are anticorrelated at the two cell tips in fission yeast. Anticorrelation suggests competition for active Cdc42 or for its effectors. Here we show how 14-3-3 protein Rad24 associates with Cdc42 guanine exchange factor (GEF) Gef1, limiting Gef1 availability to promote Cdc42 activation. Phosphorylation of Gef1 by conserved NDR kinase Orb6 promotes Gef1 binding to Rad24. Loss of Rad24–Gef1 interaction increases Gef1 protein localization and Cdc42 activation at the cell tips and reduces the anticorrelation of active Cdc42 oscillations. Increased Cdc42 activation promotes precocious bipolar growth activation, bypassing the normal requirement for an intact microtubule cytoskeleton and for microtubule-dependent polarity landmark Tea4-PP1. Further, increased Cdc42 activation by Gef1 widens cell diameter and alters tip curvature, countering the effects of Cdc42 GTPase-activating protein Rga4. The respective levels of Gef1 and Rga4 proteins at the membrane define dynamically the growing area at each cell tip. Our findings show how the 14-3-3 protein Rad24 modulates the availability of Cdc42 GEF Gef1, a homologue of mammalian Cdc42 GEF DNMBP/TUBA, to spatially control Cdc42 GTPase activity and promote cell polarization and cell shape emergence.
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Affiliation(s)
- Maitreyi Das
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL 33101
| | - Illyce Nuñez
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL 33101
| | - Marbelys Rodriguez
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL 33101
| | - David J Wiley
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL 33101
| | - Juan Rodriguez
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL 33101
| | - Ali Sarkeshik
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL 33101
| | - John R Yates
- Department of Chemical Physiology, Scripps Research Institute, La Jolla, CA 92037
| | - Peter Buchwald
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL 33101
| | - Fulvia Verde
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL 33101 Marine Biological Laboratory, Woods Hole, MA 02543. )
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45
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Subramanian K, Paul MR, Tyson JJ. Dynamical Localization of DivL and PleC in the Asymmetric Division Cycle of Caulobacter crescentus: A Theoretical Investigation of Alternative Models. PLoS Comput Biol 2015; 11:e1004348. [PMID: 26186202 PMCID: PMC4505887 DOI: 10.1371/journal.pcbi.1004348] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Accepted: 05/20/2015] [Indexed: 11/18/2022] Open
Abstract
Cell-fate asymmetry in the predivisional cell of Caulobacter crescentus requires that the regulatory protein DivL localizes to the new pole of the cell where it up-regulates CckA kinase, resulting in a gradient of CtrA~P across the cell. In the preceding stage of the cell cycle (the "stalked" cell), DivL is localized uniformly along the cell membrane and maintained in an inactive form by DivK~P. It is unclear how DivL overcomes inhibition by DivK~P in the predivisional cell simply by changing its location to the new pole. It has been suggested that co-localization of DivL with PleC phosphatase at the new pole is essential to DivL's activity there. However, there are contrasting views on whether the bifunctional enzyme, PleC, acts as a kinase or phosphatase at the new pole. To explore these ambiguities, we formulated a mathematical model of the spatiotemporal distributions of DivL, PleC and associated proteins (DivJ, DivK, CckA, and CtrA) during the asymmetric division cycle of a Caulobacter cell. By varying localization profiles of DivL and PleC in our model, we show how the physiologically observed spatial distributions of these proteins are essential for the transition from a stalked cell to a predivisional cell. Our simulations suggest that PleC is a kinase in predivisional cells, and that, by sequestering DivK~P, the kinase form of PleC enables DivL to be reactivated at the new pole. Hence, co-localization of PleC kinase and DivL is essential to establishing cellular asymmetry. Our simulations reproduce the experimentally observed spatial distribution and phosphorylation status of CtrA in wild-type and mutant cells. Based on the model, we explore novel combinations of mutant alleles, making predictions that can be tested experimentally.
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Affiliation(s)
- Kartik Subramanian
- Graduate Program in Genetics, Bioinformatics and Computational Biology, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, United States of America
| | - Mark R. Paul
- Department of Mechanical Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, United States of America
| | - John J. Tyson
- Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, United States of America
- Virginia Bioinformatics Institute, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, United States of America
- * E-mail:
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46
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Zhang Y, Wang P, Shao W, Zhu JK, Dong J. The BASL polarity protein controls a MAPK signaling feedback loop in asymmetric cell division. Dev Cell 2015; 33:136-49. [PMID: 25843888 PMCID: PMC4406870 DOI: 10.1016/j.devcel.2015.02.022] [Citation(s) in RCA: 115] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Revised: 02/16/2015] [Accepted: 02/25/2015] [Indexed: 11/24/2022]
Abstract
Cell polarization is linked to fate determination during asymmetric division of plant stem cells, but the underlying molecular mechanisms remain unknown. In Arabidopsis, BREAKING OF ASYMMETRY IN THE STOMATAL LINEAGE (BASL) is polarized to control stomatal asymmetric division. A mitogen-activated protein kinase (MAPK) cascade determines terminal stomatal fate by promoting the degradation of the lineage determinant SPEECHLESS (SPCH). Here, we demonstrate that a positive-feedback loop between BASL and the MAPK pathway constitutes a polarity module at the cortex. Cortical localization of BASL requires phosphorylation mediated by MPK3/6. Phosphorylated BASL functions as a scaffold and recruits the MAPKKK YODA and MPK3/6 to spatially concentrate signaling at the cortex. Activated MPK3/6 reinforces the feedback loop by phosphorylating BASL and inhibits stomatal fate by phosphorylating SPCH. Polarization of the BASL-MAPK signaling feedback module represents a mechanism connecting cell polarity to fate differentiation during asymmetric stem cell division in plants.
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Affiliation(s)
- Ying Zhang
- Waksman Institute of Microbiology, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Pengcheng Wang
- Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, IN 47907, USA
| | - Wanchen Shao
- Waksman Institute of Microbiology, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA; Department of Plant Biology and Pathology, Rutgers, The State University of New Jersey, Piscataway, NJ 08901, USA
| | - Jian-Kang Zhu
- Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, IN 47907, USA; Shanghai Center for Plant Stress Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Juan Dong
- Waksman Institute of Microbiology, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA; Department of Plant Biology and Pathology, Rutgers, The State University of New Jersey, Piscataway, NJ 08901, USA.
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47
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Lee C, Occhipinti P, Gladfelter AS. PolyQ-dependent RNA-protein assemblies control symmetry breaking. ACTA ACUST UNITED AC 2015; 208:533-44. [PMID: 25713414 PMCID: PMC4347642 DOI: 10.1083/jcb.201407105] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Transcripts encoding polarity factors such as Bni1 and Spa2 are nonrandomly clustered in the cytosol to initiate and maintain sites of polarized growth in the fungus Ashbya gossypii. Dendritic growth in fungi and neurons requires that multiple axes of polarity are established and maintained within the same cytoplasm. We have discovered that transcripts encoding key polarity factors including a formin, Bni1, and a polarisome scaffold, Spa2, are nonrandomly clustered in the cytosol to initiate and maintain sites of polarized growth in the fungus Ashbya gossypii. This asymmetric distribution requires the mRNAs to interact with a polyQ-containing protein, Whi3, and a Pumilio protein with a low-complexity sequence, Puf2. Cells lacking Whi3 or Puf2 had severe defects in establishing new sites of polarity and failed to localize Bni1 protein. Interaction of mRNAs with Whi3 and Puf2 promotes enrichment of transcripts at established sites of polarized growth and clustering of polarity transcripts throughout the cell body. Thus, aggregation-prone proteins make functional assemblies to position polarity transcripts, and nonrandom positioning of transcripts is required for symmetry-breaking events. This reveals a physiological function for polyQ-driven assemblies in regulating cell polarity.
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Affiliation(s)
- ChangHwan Lee
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755
| | | | - Amy S Gladfelter
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755
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48
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Kelley JB, Dixit G, Sheetz JB, Venkatapurapu SP, Elston TC, Dohlman HG. RGS proteins and septins cooperate to promote chemotropism by regulating polar cap mobility. Curr Biol 2015; 25:275-285. [PMID: 25601550 DOI: 10.1016/j.cub.2014.11.047] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Revised: 10/26/2014] [Accepted: 11/17/2014] [Indexed: 11/29/2022]
Abstract
BACKGROUND Septins are well known to form a boundary between mother and daughter cells in mitosis, but their role in other morphogenic states is poorly understood. RESULTS Using microfluidics and live-cell microscopy, coupled with new computational methods for image analysis, we investigated septin function during pheromone-dependent chemotropic growth in yeast. We show that septins colocalize with the regulator of G protein signaling (RGS) Sst2, a GTPase-activating protein that dampens pheromone receptor signaling. We show further that the septin structure surrounds the polar cap, ensuring that cell growth is directed toward the source of pheromone. When RGS activity is abrogated, septins are partially disorganized. Under these circumstances, the polar cap travels toward septin structures and away from sites of exocytosis, resulting in a loss of gradient tracking. CONCLUSIONS Septin organization is dependent on RGS protein activity. When assembled correctly, septins promote turning of the polar cap and proper tracking of a pheromone gradient.
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Affiliation(s)
- Joshua B Kelley
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, 120 Mason Farm Road, 3046 Genetic Medicine Building, Campus Box 7260, Chapel Hill, NC 27599, USA; Department of Pharmacology, University of North Carolina at Chapel Hill, 120 Mason Farm Road, 4009 Genetic Medicine Building, Campus Box 7365, Chapel Hill, NC 27599, USA
| | - Gauri Dixit
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, 120 Mason Farm Road, 3046 Genetic Medicine Building, Campus Box 7260, Chapel Hill, NC 27599, USA
| | - Joshua B Sheetz
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, 120 Mason Farm Road, 3046 Genetic Medicine Building, Campus Box 7260, Chapel Hill, NC 27599, USA
| | - Sai Phanindra Venkatapurapu
- Department of Pharmacology, University of North Carolina at Chapel Hill, 120 Mason Farm Road, 4009 Genetic Medicine Building, Campus Box 7365, Chapel Hill, NC 27599, USA; Curriculum in Bioinformatics and Computational Biology, University of North Carolina at Chapel Hill, 120 Mason Farm Road, 4092 Genetic Medicine Building, Campus Box 7365, Chapel Hill, NC 27599, USA
| | - Timothy C Elston
- Department of Pharmacology, University of North Carolina at Chapel Hill, 120 Mason Farm Road, 4009 Genetic Medicine Building, Campus Box 7365, Chapel Hill, NC 27599, USA.
| | - Henrik G Dohlman
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, 120 Mason Farm Road, 3046 Genetic Medicine Building, Campus Box 7260, Chapel Hill, NC 27599, USA; Department of Pharmacology, University of North Carolina at Chapel Hill, 120 Mason Farm Road, 4009 Genetic Medicine Building, Campus Box 7365, Chapel Hill, NC 27599, USA.
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49
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Oscillatory AAA+ ATPase Knk1 constitutes a novel morphogenetic pathway in fission yeast. Proc Natl Acad Sci U S A 2014; 111:17899-904. [PMID: 25422470 DOI: 10.1073/pnas.1407226111] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Cellular morphogenesis relies partly on cell polarization by the cytoskeleton. In the fission yeast Schizosaccharomyces pombe, it is well established that microtubules (MTs) deliver the spatial cue Tea1, a kelch repeat protein, to the tip regions to direct the growth machinery at the cell tips driving the linear extension of the rod-shaped organism to maintain a straight long axis. Here, we report the characterization of Knk1 (kink), a previously unidentified member of the superfamily of ATPases associated with various cellular activities (AAA(+)), whose deletion causes a unique morphological defect characterized by the formation of kinks close to cell tips. Through genetic analysis, we place Knk1 into a novel pathway controlling cell shape independently of MTs and Tea1. Knk1 localizes at cell tips. Its localization is mediated by the Knk1 N terminus and is enhanced upon ATP binding to the C-terminal ATPase domain. Furthermore, Knk1 tip recruitment is regulated by SRC-like adaptor 2 (Sla2) and cell division cycle 42 (Cdc42) independently of Sla2's role in endocytosis. Finally, we discovered that Knk1 shows an anticorrelated oscillatory behavior between the two cell tips at a periodicity that is different from the reported oscillatory Cdc42 dynamics.
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50
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Abstract
Systems biology has recently achieved significant success in the understanding of complex interconnected phenomena such as cell polarity and migration. In this context, the definition of systems biology has come to encompass the integration of quantitative measurements with sophisticated modeling approaches. This article will review recent progress in live cell imaging technologies that have expanded the possibilities of quantitative in vivo measurements, particularly in regards to molecule counting and quantitative measurements of protein concentration and dynamics. These methods have gained and continue to gain popularity with the biological community. In general, we will discuss three broad categories: protein interactions, protein quantitation, and protein dynamics.
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Affiliation(s)
- Sarah E Smith
- a Stowers Institute for Medical Research ; Kansas City , MO USA
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