1
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Bement WM, Goryachev AB, Miller AL, von Dassow G. Patterning of the cell cortex by Rho GTPases. Nat Rev Mol Cell Biol 2024; 25:290-308. [PMID: 38172611 DOI: 10.1038/s41580-023-00682-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/20/2023] [Indexed: 01/05/2024]
Abstract
The Rho GTPases - RHOA, RAC1 and CDC42 - are small GTP binding proteins that regulate basic biological processes such as cell locomotion, cell division and morphogenesis by promoting cytoskeleton-based changes in the cell cortex. This regulation results from active (GTP-bound) Rho GTPases stimulating target proteins that, in turn, promote actin assembly and myosin 2-based contraction to organize the cortex. This basic regulatory scheme, well supported by in vitro studies, led to the natural assumption that Rho GTPases function in vivo in an essentially linear matter, with a given process being initiated by GTPase activation and terminated by GTPase inactivation. However, a growing body of evidence based on live cell imaging, modelling and experimental manipulation indicates that Rho GTPase activation and inactivation are often tightly coupled in space and time via signalling circuits and networks based on positive and negative feedback. In this Review, we present and discuss this evidence, and we address one of the fundamental consequences of coupled activation and inactivation: the ability of the Rho GTPases to self-organize, that is, direct their own transition from states of low order to states of high order. We discuss how Rho GTPase self-organization results in the formation of diverse spatiotemporal cortical patterns such as static clusters, oscillatory pulses, travelling wave trains and ring-like waves. Finally, we discuss the advantages of Rho GTPase self-organization and pattern formation for cell function.
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Affiliation(s)
- William M Bement
- Center for Quantitative Cell Imaging, Department of Integrative Biology, University of Wisconsin-Madison, Madison, WI, USA.
| | - Andrew B Goryachev
- Center for Engineering Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK.
| | - Ann L Miller
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA.
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2
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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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3
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Chiou JG, Moran KD, Lew DJ. How cells determine the number of polarity sites. eLife 2021; 10:e58768. [PMID: 33899733 PMCID: PMC8116050 DOI: 10.7554/elife.58768] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Accepted: 04/23/2021] [Indexed: 12/15/2022] Open
Abstract
The diversity of cell morphologies arises, in part, through regulation of cell polarity by Rho-family GTPases. A poorly understood but fundamental question concerns the regulatory mechanisms by which different cells generate different numbers of polarity sites. Mass-conserved activator-substrate (MCAS) models that describe polarity circuits develop multiple initial polarity sites, but then those sites engage in competition, leaving a single winner. Theoretical analyses predicted that competition would slow dramatically as GTPase concentrations at different polarity sites increase toward a 'saturation point', allowing polarity sites to coexist. Here, we test this prediction using budding yeast cells, and confirm that increasing the amount of key polarity proteins results in multiple polarity sites and simultaneous budding. Further, we elucidate a novel design principle whereby cells can switch from competition to equalization among polarity sites. These findings provide insight into how cells with diverse morphologies may determine the number of polarity sites.
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Affiliation(s)
- Jian-geng Chiou
- Department of Pharmacology and Cancer Biology, Duke University Medical CenterDurhamUnited States
| | - Kyle D Moran
- Department of Pharmacology and Cancer Biology, Duke University Medical CenterDurhamUnited States
| | - Daniel J Lew
- Department of Pharmacology and Cancer Biology, Duke University Medical CenterDurhamUnited States
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4
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Gubieda AG, Packer JR, Squires I, Martin J, Rodriguez J. Going with the flow: insights from Caenorhabditis elegans zygote polarization. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190555. [PMID: 32829680 PMCID: PMC7482210 DOI: 10.1098/rstb.2019.0555] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/09/2020] [Indexed: 12/12/2022] Open
Abstract
Cell polarity is the asymmetric distribution of cellular components along a defined axis. Polarity relies on complex signalling networks between conserved patterning proteins, including the PAR (partitioning defective) proteins, which become segregated in response to upstream symmetry breaking cues. Although the mechanisms that drive the asymmetric localization of these proteins are dependent upon cell type and context, in many cases the regulation of actomyosin cytoskeleton dynamics is central to the transport, recruitment and/or stabilization of these polarity effectors into defined subcellular domains. The transport or advection of PAR proteins by an actomyosin flow was first observed in the Caenorhabditis elegans zygote more than a decade ago. Since then a multifaceted approach, using molecular methods, high-throughput screens, and biophysical and computational models, has revealed further aspects of this flow and how polarity regulators respond to and modulate it. Here, we review recent findings on the interplay between actomyosin flow and the PAR patterning networks in the polarization of the C. elegans zygote. We also discuss how these discoveries and developed methods are shaping our understanding of other flow-dependent polarizing systems. This article is part of a discussion meeting issue 'Contemporary morphogenesis'.
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Affiliation(s)
| | | | | | | | - Josana Rodriguez
- Biosciences Institute, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
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5
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Ignacio DP, Coffman VC, Dawes AT. Centriole Biogenesis: Symmetry Breaking and Site Selection. Trends Cell Biol 2018; 29:3-5. [PMID: 30470626 DOI: 10.1016/j.tcb.2018.11.001] [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: 11/02/2018] [Accepted: 11/02/2018] [Indexed: 10/27/2022]
Abstract
Centrioles must duplicate as cells progress through the cell cycle but it is unclear how the site of duplication is selected. A recent computational study demonstrates that two separate but interacting feedback mechanisms (autocatalytic activation and substrate depletion) are capable of selecting a single site for centriole biogenesis.
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Affiliation(s)
- David P Ignacio
- Molecular, Cellular and Developmental Biology Graduate Program, The Ohio State University, Columbus, OH 43210, USA
| | - Valerie C Coffman
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210, USA
| | - Adriana T Dawes
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210, USA; Department of Mathematics, The Ohio State University, Columbus, OH 43210, USA.
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6
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Moran KD, Kang H, Araujo AV, Zyla TR, Saito K, Tsygankov D, Lew DJ. Cell-cycle control of cell polarity in yeast. J Cell Biol 2018; 218:171-189. [PMID: 30459262 PMCID: PMC6314536 DOI: 10.1083/jcb.201806196] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 09/21/2018] [Accepted: 10/18/2018] [Indexed: 11/30/2022] Open
Abstract
In Saccharomyces cerevisiae, polarization of Cdc42 is regulated by the cell cycle, but the regulatory mechanisms are not well understood. Moran et al. show that G1 cyclin–dependent kinase activity enables localization of a subset of Cdc42 effectors to sites enriched for Cdc42. In many cells, morphogenetic events are coordinated with the cell cycle by cyclin-dependent kinases (CDKs). For example, many mammalian cells display extended morphologies during interphase but round up into more spherical shapes during mitosis (high CDK activity) and constrict a furrow during cytokinesis (low CDK activity). In the budding yeast Saccharomyces cerevisiae, bud formation reproducibly initiates near the G1/S transition and requires activation of CDKs at a point called “start” in G1. Previous work suggested that CDKs acted by controlling the ability of cells to polarize Cdc42, a conserved Rho-family GTPase that regulates cell polarity and the actin cytoskeleton in many systems. However, we report that yeast daughter cells can polarize Cdc42 before CDK activation at start. This polarization operates via a positive feedback loop mediated by the Cdc42 effector Ste20. We further identify a major and novel locus of CDK action downstream of Cdc42 polarization, affecting the ability of several other Cdc42 effectors to localize to the polarity site.
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Affiliation(s)
- Kyle D Moran
- Department of Pharmacology and Cancer Biology, Duke University, Durham, NC
| | - Hui Kang
- Department of Pharmacology and Cancer Biology, Duke University, Durham, NC
| | - Ana V Araujo
- Department of Pharmacology and Cancer Biology, Duke University, Durham, NC
| | - Trevin R Zyla
- Department of Pharmacology and Cancer Biology, Duke University, Durham, NC
| | - Koji Saito
- Department of Biosciences, School of Science, Kitasato University, Kitasato, Sagamihara, Kanagawa, Japan
| | - Denis Tsygankov
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, GA
| | - Daniel J Lew
- Department of Pharmacology and Cancer Biology, Duke University, Durham, NC
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7
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Abstract
A conserved molecular machinery centered on the Cdc42 GTPase regulates cell polarity in diverse organisms. Here we review findings from budding and fission yeasts that reveal both a conserved core polarity circuit and several adaptations that each organism exploits to fulfill the needs of its lifestyle. The core circuit involves positive feedback by local activation of Cdc42 to generate a cluster of concentrated GTP-Cdc42 at the membrane. Species-specific pathways regulate the timing of polarization during the cell cycle, as well as the location and number of polarity sites.
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Affiliation(s)
- Jian-Geng Chiou
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710;
| | - Mohan K Balasubramanian
- Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Daniel J Lew
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710;
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8
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Goryachev AB, Leda M. Many roads to symmetry breaking: molecular mechanisms and theoretical models of yeast cell polarity. Mol Biol Cell 2017; 28:370-380. [PMID: 28137950 PMCID: PMC5341721 DOI: 10.1091/mbc.e16-10-0739] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 11/17/2016] [Accepted: 11/23/2016] [Indexed: 01/08/2023] Open
Abstract
Mathematical modeling has been instrumental in identifying common principles of cell polarity across diverse systems. These principles include positive feedback loops that are required to destabilize a spatially uniform state of the cell. The conserved small G-protein Cdc42 is a master regulator of eukaryotic cellular polarization. Here we discuss recent developments in studies of Cdc42 polarization in budding and fission yeasts and demonstrate that models describing symmetry-breaking polarization can be classified into six minimal classes based on the structure of positive feedback loops that activate and localize Cdc42. Owing to their generic system-independent nature, these model classes are also likely to be relevant for the G-protein–based symmetry-breaking systems of higher eukaryotes. We review experimental evidence pro et contra different theoretically plausible models and conclude that several parallel and non–mutually exclusive mechanisms are likely involved in cellular polarization of yeasts. This potential redundancy needs to be taken into consideration when interpreting the results of recent cell-rewiring studies.
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Affiliation(s)
- Andrew B Goryachev
- Center for Synthetic and Systems Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, United Kingdom
| | - Marcin Leda
- Center for Synthetic and Systems Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, United Kingdom
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9
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Geymonat M, Segal M. Intrinsic and Extrinsic Determinants Linking Spindle Pole Fate, Spindle Polarity, and Asymmetric Cell Division in the Budding Yeast S. cerevisiae. Results Probl Cell Differ 2017; 61:49-82. [PMID: 28409300 DOI: 10.1007/978-3-319-53150-2_3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The budding yeast S. cerevisiae is a powerful model to understand the multiple layers of control driving an asymmetric cell division. In budding yeast, asymmetric targeting of the spindle poles to the mother and bud cell compartments respectively orients the mitotic spindle along the mother-bud axis. This program exploits an intrinsic functional asymmetry arising from the age distinction between the spindle poles-one inherited from the preceding division and the other newly assembled. Extrinsic mechanisms convert this age distinction into differential fate. Execution of this program couples spindle orientation with the segregation of the older spindle pole to the bud. Remarkably, similar stereotyped patterns of inheritance occur in self-renewing stem cell divisions underscoring the general importance of studying spindle polarity and differential fate in yeast. Here, we review the mechanisms accounting for this pivotal interplay between intrinsic and extrinsic asymmetries that translate spindle pole age into differential fate.
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Affiliation(s)
- Marco Geymonat
- Department of Genetics, University of Cambridge, Downing Street, Cambridge, CB2 3EH, UK
| | - Marisa Segal
- Department of Genetics, University of Cambridge, Downing Street, Cambridge, CB2 3EH, UK.
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10
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Lu R, Wilson JM. Rab14 specifies the apical membrane through Arf6-mediated regulation of lipid domains and Cdc42. Sci Rep 2016; 6:38249. [PMID: 27901125 PMCID: PMC5128791 DOI: 10.1038/srep38249] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Accepted: 11/07/2016] [Indexed: 12/13/2022] Open
Abstract
The generation of cell polarity is essential for the development of multi-cellular organisms as well as for the function of epithelial organs in the mature animal. Small GTPases regulate the establishment and maintenance of polarity through effects on cytoskeleton, membrane trafficking, and signaling. Using short-term 3-dimensional culture of MDCK cells, we find that the small GTPase Rab14 is required for apical membrane specification. Rab14 knockdown results in disruption of polarized lipid domains and failure of the Par/aPKC/Cdc42 polarity complex to localize to the apical membrane. These effects are mediated through tight control of lipid localization, as overexpression of the phosphatidylinositol 4-phosphate 5-kinase α [PtdIns(4)P5K] activator Arf6 or PtdIns(4)P5K alone, or treatment with the phosphatidylinositol 3-kinase (PtdInsI3K) inhibitor wortmannin, rescued the multiple-apical domain phenotype observed after Rab14 knockdown. Rab14 also co-immunoprecipitates and colocalizes with the small GTPase Cdc42, and Rab14 knockdown results in increased Cdc42 activity. Furthermore, Rab14 regulates trafficking of vesicles to the apical domain, mitotic spindle orientation, and midbody position, consistent with Rab14’s reported localization to the midbody as well as its effects upon Cdc42. These results position Rab14 at the top of a molecular cascade that regulates the establishment of cell polarity.
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Affiliation(s)
- Ruifeng Lu
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ 85724, USA
| | - Jean M Wilson
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ 85724, USA
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11
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Woods B, Lai H, Wu CF, Zyla TR, Savage NS, Lew DJ. Parallel Actin-Independent Recycling Pathways Polarize Cdc42 in Budding Yeast. Curr Biol 2016; 26:2114-26. [PMID: 27476596 DOI: 10.1016/j.cub.2016.06.047] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Revised: 05/03/2016] [Accepted: 06/21/2016] [Indexed: 12/31/2022]
Abstract
The highly conserved Rho-family GTPase Cdc42 is an essential regulator of polarity in many different cell types. During polarity establishment, Cdc42 becomes concentrated at a cortical site, where it interacts with downstream effectors to orient the cytoskeleton along the front-back axis. To concentrate Cdc42, loss of Cdc42 by diffusion must be balanced by recycling to the front. In Saccharomyces cerevisiae, the guanine nucleotide dissociation inhibitor (GDI) Rdi1 recycles Cdc42 through the cytoplasm. Loss of Rdi1 slowed but did not eliminate Cdc42 accumulation at the front, suggesting the existence of other recycling pathways. One proposed pathway involves actin-directed trafficking of vesicles carrying Cdc42 to the front. However, we found no role for F-actin in Cdc42 concentration, even in rdi1Δ cells. Instead, Cdc42 was still able to exchange between the membrane and cytoplasm in rdi1Δ cells, albeit at a reduced rate. Membrane-cytoplasm exchange of GDP-Cdc42 was faster than that of GTP-Cdc42, and computational modeling indicated that such exchange would suffice to promote polarization. We also uncovered a novel role for the Cdc42-directed GTPase-activating protein (GAP) Bem2 in Cdc42 polarization. Bem2 was known to act in series with Rdi1 to promote recycling of Cdc42, but we found that rdi1Δ bem2Δ mutants were synthetically lethal, suggesting that they also act in parallel. We suggest that GAP activity cooperates with the GDI to counteract the dissipative effect of a previously unappreciated pathway whereby GTP-Cdc42 escapes from the polarity site through the cytoplasm.
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Affiliation(s)
- Benjamin Woods
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA
| | - Helen Lai
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA
| | - Chi-Fang Wu
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA
| | - Trevin R Zyla
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA
| | - Natasha S Savage
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, UK.
| | - Daniel J Lew
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA.
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12
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Guo PP, Yong JYA, Wang YM, Li CR. Sec15 links bud site selection to polarised cell growth and exocytosis in Candida albicans. Sci Rep 2016; 6:26464. [PMID: 27225289 PMCID: PMC4881018 DOI: 10.1038/srep26464] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 05/04/2016] [Indexed: 01/17/2023] Open
Abstract
The exocyst plays a crucial role in the targeting of secretory vesicles to the plasma membrane during exocytosis. It has been shown to be involved in diverse cellular processes including yeast budding. However, the mechanism of the exocyst regulating yeast budding has not been fully elucidated. Here we report a novel interaction between the exocyst component Sec15 and the Ras-family GTPase Rsr1, a master regulator of bud-site-selection system, in the fungus Candida albicans. We present several lines of evidence indicating physical and genetic interaction of Sec15 with Rsr1. In vitro binding assays and co-immunoprecipitation studies showed that Sec15 associated physically with Rsr1. Deletion of RSR1 completely abolished the polarised localisation of Sec15 as well as all the other exocyst components in both yeast and hyphal cells, suggesting a functional interaction between Sec15 and Rsr1. We also show that C. albicans Sec15 interacts directly with the polarity determinant Bem1 and the type V myosin, Myo2. Disruption of the interaction by shutting off SEC15 results in mislocaliztion of Bem1-GFP. These findings highlight the important role of Sec15 in polarised cell growth by providing a direct functional link between bud-site-selection and exocytosis.
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Affiliation(s)
- Pan Pan Guo
- Institute of Health Sciences, Anhui University, Hefei 230601, China
| | - Jie Ying Au Yong
- Institute of Molecular and Cell Biology, A*STAR, 61 Biopolis Drive, 138673 Singapore
| | - Yan Ming Wang
- Institute of Molecular and Cell Biology, A*STAR, 61 Biopolis Drive, 138673 Singapore
| | - Chang Run Li
- Institute of Health Sciences, Anhui University, Hefei 230601, China
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13
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Fujiwara M, Okamoto M, Hori M, Suga H, Jikihara H, Sugihara Y, Shimamoto F, Mori T, Nakaoji K, Hamada K, Ota T, Wiedemuth R, Temme A, Tatsuka M. Radiation-Induced RhoGDIβ Cleavage Leads to Perturbation of Cell Polarity: A Possible Link to Cancer Spreading. J Cell Physiol 2016; 231:2493-505. [DOI: 10.1002/jcp.25362] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2015] [Accepted: 02/23/2016] [Indexed: 01/17/2023]
Affiliation(s)
- Mamoru Fujiwara
- Faculty of Life and Environmental Sciences; Department of Life Sciences; Prefectural University of Hiroshima; Shoubara Hiroshima Japan
| | - Mayumi Okamoto
- Faculty of Life and Environmental Sciences; Department of Life Sciences; Prefectural University of Hiroshima; Shoubara Hiroshima Japan
| | - Masato Hori
- Faculty of Life and Environmental Sciences; Department of Life Sciences; Prefectural University of Hiroshima; Shoubara Hiroshima Japan
| | - Hiroshi Suga
- Faculty of Life and Environmental Sciences; Department of Life Sciences; Prefectural University of Hiroshima; Shoubara Hiroshima Japan
| | - Hiroshi Jikihara
- Department of Health Sciences; Faculty of Human Culture and Science; Prefectural University of Hiroshima; Minami-ku Hiroshima Japan
| | - Yuka Sugihara
- Department of Health Sciences; Faculty of Human Culture and Science; Prefectural University of Hiroshima; Minami-ku Hiroshima Japan
| | - Fumio Shimamoto
- Department of Health Sciences; Faculty of Human Culture and Science; Prefectural University of Hiroshima; Minami-ku Hiroshima Japan
| | - Toshio Mori
- Radioisotope Research Center; Nara Medical University School of Medicine; Kashihara Nara Japan
| | - Koichi Nakaoji
- Research & Development Division; Pias Corporation; Kobe Japan
| | - Kazuhiko Hamada
- Research & Development Division; Pias Corporation; Kobe Japan
| | - Takahide Ota
- Department of Life Science; Medical Research Institute; Kanazawa Medical University; Uchinada Ishikawa Japan
| | - Ralf Wiedemuth
- Department of Neurosurgery; University Hospital Carl Gustav Carus; Technical University Dresden; Dresden Germany
| | - Achim Temme
- Department of Neurosurgery; University Hospital Carl Gustav Carus; Technical University Dresden; Dresden Germany
| | - Masaaki Tatsuka
- Faculty of Life and Environmental Sciences; Department of Life Sciences; Prefectural University of Hiroshima; Shoubara Hiroshima Japan
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14
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Woods B, Kuo CC, Wu CF, Zyla TR, Lew DJ. Polarity establishment requires localized activation of Cdc42. J Cell Biol 2016; 211:19-26. [PMID: 26459595 PMCID: PMC4602047 DOI: 10.1083/jcb.201506108] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Positive feedback by localized activation of Cdc42 drives polarity establishment in the budding yeast Saccharomyces cerevisiae. Establishment of cell polarity in animal and fungal cells involves localization of the conserved Rho-family guanosine triphosphatase, Cdc42, to the cortical region destined to become the “front” of the cell. The high local concentration of active Cdc42 promotes cytoskeletal polarization through various effectors. Cdc42 accumulation at the front is thought to involve positive feedback, and studies in the budding yeast Saccharomyces cerevisiae have suggested distinct positive feedback mechanisms. One class of mechanisms involves localized activation of Cdc42 at the front, whereas another class involves localized delivery of Cdc42 to the front. Here we show that Cdc42 activation must be localized for successful polarity establishment, supporting local activation rather than local delivery as the dominant mechanism in this system.
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Affiliation(s)
- Benjamin Woods
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710
| | - Chun-Chen Kuo
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710
| | - Chi-Fang Wu
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710
| | - Trevin R Zyla
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710
| | - Daniel J Lew
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710
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15
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Wu CF, Chiou JG, Minakova M, Woods B, Tsygankov D, Zyla TR, Savage NS, Elston TC, Lew DJ. Role of competition between polarity sites in establishing a unique front. eLife 2015; 4:e11611. [PMID: 26523396 PMCID: PMC4728132 DOI: 10.7554/elife.11611] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 11/01/2015] [Indexed: 01/15/2023] Open
Abstract
Polarity establishment in many cells is thought to occur via positive feedback that reinforces even tiny asymmetries in polarity protein distribution. Cdc42 and related GTPases are activated and accumulate in a patch of the cortex that defines the front of the cell. Positive feedback enables spontaneous polarization triggered by stochastic fluctuations, but as such fluctuations can occur at multiple locations, how do cells ensure that they make only one front? In polarizing cells of the model yeast Saccharomyces cerevisiae, positive feedback can trigger growth of several Cdc42 clusters at the same time, but this multi-cluster stage rapidly evolves to a single-cluster state, which then promotes bud emergence. By manipulating polarity protein dynamics, we show that resolution of multi-cluster intermediates occurs through a greedy competition between clusters to recruit and retain polarity proteins from a shared intracellular pool.
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Affiliation(s)
- Chi-Fang Wu
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, United States
| | - Jian-Geng Chiou
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, United States
| | - Maria Minakova
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, United States
| | - Benjamin Woods
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, United States
| | - Denis Tsygankov
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, United States
| | - Trevin R Zyla
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, United States
| | - Natasha S Savage
- Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Timothy C Elston
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, United States
| | - Daniel J Lew
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, United States
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16
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Martin SG. Spontaneous cell polarization: Feedback control of Cdc42 GTPase breaks cellular symmetry. Bioessays 2015; 37:1193-201. [PMID: 26338468 DOI: 10.1002/bies.201500077] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Spontaneous polarization without spatial cues, or symmetry breaking, is a fundamental problem of spatial organization in biological systems. This question has been extensively studied using yeast models, which revealed the central role of the small GTPase switch Cdc42. Active Cdc42-GTP forms a coherent patch at the cell cortex, thought to result from amplification of a small initial stochastic inhomogeneity through positive feedback mechanisms, which induces cell polarization. Here, I review and discuss the mechanisms of Cdc42 activity self-amplification and dynamic turnover. A robust Cdc42 patch is formed through the combined effects of Cdc42 activity promoting its own activation and active Cdc42-GTP displaying reduced membrane detachment and lateral diffusion compared to inactive Cdc42-GDP. I argue the role of the actin cytoskeleton in symmetry breaking is not primarily to transport Cdc42 to the active site. Finally, negative feedback and competition mechanisms serve to control the number of polarization sites.
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Affiliation(s)
- Sophie G Martin
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
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Lee ME, Lo WC, Miller KE, Chou CS, Park HO. Regulation of Cdc42 polarization by the Rsr1 GTPase and Rga1, a Cdc42 GTPase-activating protein, in budding yeast. J Cell Sci 2015; 128:2106-17. [PMID: 25908844 DOI: 10.1242/jcs.166538] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Accepted: 03/30/2015] [Indexed: 01/05/2023] Open
Abstract
Cdc42 plays a central role in establishing polarity in yeast and animals, yet how polarization of Cdc42 is achieved in response to spatial cues is poorly understood. Using live-cell imaging, we found distinct dynamics of Cdc42 polarization in haploid budding yeast in correlation with two temporal steps of the G1 phase. The position at which the Cdc42-GTP cluster develops changes rapidly around the division site during the first step but becomes stabilized in the second step, suggesting that an axis of polarized growth is determined in mid G1. Cdc42 polarization in the first step and its proper positioning depend on Rsr1 and its GTPase-activating protein (GAP) Bud2. Interestingly, Rga1, a Cdc42 GAP, exhibits transient localization to a site near the bud neck and to the division site during cytokinesis and G1, and this temporal change of Rga1 distribution is necessary for determination of a proper growth site. Mathematical modeling suggests that a proper axis of Cdc42 polarization in haploid cells might be established through a biphasic mechanism involving sequential positive feedback and transient negative feedback.
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Affiliation(s)
- Mid Eum Lee
- Molecular Cellular Developmental Biology Program, The Ohio State University, Columbus, OH 43210, USA
| | - Wing-Cheong Lo
- Mathematical Biosciences Institute, The Ohio State University, Columbus, OH 43210, USA
| | - Kristi E Miller
- Molecular Cellular Developmental Biology Program, The Ohio State University, Columbus, OH 43210, USA
| | - Ching-Shan Chou
- Mathematical Biosciences Institute, The Ohio State University, Columbus, OH 43210, USA Department of Mathematics, The Ohio State University, Columbus, OH 43210, USA
| | - Hay-Oak Park
- Molecular Cellular Developmental Biology Program, The Ohio State University, Columbus, OH 43210, USA Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210, USA
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Tartakoff AM. Cell biology of yeast zygotes, from genesis to budding. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1853:1702-14. [PMID: 25862405 DOI: 10.1016/j.bbamcr.2015.03.018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 03/28/2015] [Accepted: 03/31/2015] [Indexed: 12/23/2022]
Abstract
The zygote is the essential intermediate that allows interchange of nuclear, mitochondrial and cytosolic determinants between cells. Zygote formation in Saccharomyces cerevisiae is accomplished by mechanisms that are not characteristic of mitotic cells. These include shifting the axis of growth away from classical cortical landmarks, dramatically reorganizing the cell cortex, remodeling the cell wall in preparation for cell fusion, fusing with an adjacent partner, accomplishing nuclear fusion, orchestrating two steps of septin morphogenesis that account for a delay in fusion of mitochondria, and implementing new norms for bud site selection. This essay emphasizes the sequence of dependent relationships that account for this progression from cell encounters through zygote budding. It briefly summarizes classical studies of signal transduction and polarity specification and then focuses on downstream events.
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Affiliation(s)
- Alan M Tartakoff
- Department of Pathology and Cell Biology Program, Case Western Reserve University, Cleveland, OH 44106, USA.
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Sequential logic of polarity determination during the haploid-to-diploid transition in Saccharomyces cerevisiae. EUKARYOTIC CELL 2014; 13:1393-402. [PMID: 25172767 DOI: 10.1128/ec.00161-14] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
In many organisms, the geometry of encounter of haploid germ cells is arbitrary. In Saccharomyces cerevisiae, the resulting zygotes have been seen to bud asymmetrically in several directions as they produce diploid progeny. What mechanisms account for the choice of direction, and do the mechanisms directing polarity change over time? Distinct subgroups of cortical "landmark" proteins guide budding by haploid versus diploid cells, both of which require the Bud1/Rsr1 GTPase to link landmarks to actin. We observed that as mating pairs of haploid cells form zygotes, bud site specification progresses through three phases. The first phase follows disassembly and limited scattering of proteins that concentrated at the zone of cell contact, followed by their reassembly to produce a large medial bud. Bud1 is not required for medial placement of the initial bud. The second phase produces a contiguous bud(s) and depends on axial landmarks. As the titer of the Axl1 landmark diminishes, the third phase ultimately redirects budding toward terminal sites and is promoted by bipolar landmarks. Thus, following the initial random encounter that specifies medial budding, sequential spatial choices are orchestrated by the titer of a single cortical determinant that determines whether successive buds will be contiguous to their predecessors.
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Kuo CC, Savage NS, Chen H, Wu CF, Zyla TR, Lew DJ. Inhibitory GEF phosphorylation provides negative feedback in the yeast polarity circuit. Curr Biol 2014; 24:753-9. [PMID: 24631237 PMCID: PMC4018745 DOI: 10.1016/j.cub.2014.02.024] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Revised: 01/21/2014] [Accepted: 02/11/2014] [Indexed: 11/15/2022]
Abstract
Cell polarity is critical for the form and function of many cell types. During polarity establishment, cells define a cortical "front" that behaves differently from the rest of the cortex. The front accumulates high levels of the active form of a polarity-determining Rho-family GTPase (Cdc42, Rac, or Rop) that then orients cytoskeletal elements through various effectors to generate the polarized morphology appropriate to the particular cell type [1, 2]. GTPase accumulation is thought to involve positive feedback, such that active GTPase promotes further delivery and/or activation of more GTPase in its vicinity [3]. Recent studies suggest that once a front forms, the concentration of polarity factors at the front can increase and decrease periodically, first clustering the factors at the cortex and then dispersing them back to the cytoplasm [4-7]. Such oscillatory behavior implies the presence of negative feedback in the polarity circuit [8], but the mechanism of negative feedback was not known. Here we show that, in the budding yeast Saccharomyces cerevisiae, the catalytic activity of the Cdc42-directed GEF is inhibited by Cdc42-stimulated effector kinases, thus providing negative feedback. We further show that replacing the GEF with a phosphosite mutant GEF abolishes oscillations and leads to the accumulation of excess GTP-Cdc42 and other polarity factors at the front. These findings reveal a mechanism for negative feedback and suggest that the function of negative feedback via GEF inhibition is to buffer the level of Cdc42 at the polarity site.
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Affiliation(s)
- Chun-Chen Kuo
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA
| | - Natasha S Savage
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, UK
| | - Hsin Chen
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA
| | - Chi-Fang Wu
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA
| | - Trevin R Zyla
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA
| | - Daniel J Lew
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA.
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Csikász-Nagy A, Sato M, Carazo Salas RE. Projecting cell polarity into the next decade. Philos Trans R Soc Lond B Biol Sci 2013; 368:20130001. [PMID: 24062575 DOI: 10.1098/rstb.2013.0001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
- Attila Csikász-Nagy
- Research and Innovation Center, Fondazione Edmund Mach, , San Michele all'Adige-38010, Italy
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