1
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Pujari AN, Cullen PJ. Modulators of MAPK pathway activity during filamentous growth in Saccharomyces cerevisiae. G3 (BETHESDA, MD.) 2024; 14:jkae072. [PMID: 38560781 PMCID: PMC11152069 DOI: 10.1093/g3journal/jkae072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 12/22/2023] [Accepted: 03/21/2024] [Indexed: 04/04/2024]
Abstract
Mitogen-activated protein kinase (MAPK) pathways control the response to intrinsic and extrinsic stimuli. In the budding yeast Saccharomyces cerevisiae, cells undergo filamentous growth, which is regulated by the fMAPK pathway. To better understand the regulation of the fMAPK pathway, a genetic screen was performed to identify spontaneous mutants with elevated activity of an fMAPK pathway-dependent growth reporter (ste4 FUS1-HIS3). In total, 159 mutants were isolated and analyzed by secondary screens for invasive growth by the plate-washing assay and filament formation by microscopy. Thirty-two mutants were selected for whole-genome sequencing, which identified new alleles in genes encoding known regulators of the fMAPK pathway. These included gain-of-function alleles in STE11, which encodes the MAPKKK, as well as loss-of-function alleles in KSS1, which encodes the MAP kinase, and loss-of-function alleles in RGA1, which encodes a GTPase-activating protein (GAP) for CDC42. New alleles in previously identified pathway modulators were also uncovered in ALY1, AIM44, RCK2, IRA2, REG1, and in genes that regulate protein folding (KAR2), glycosylation (MNN4), and turnover (BLM10). Mutations leading to C-terminal truncations in the transcription factor Ste12p were also uncovered that resulted in elevated reporter activity, identifying an inhibitory domain of the protein from residues 491 to 688. We also find that a diversity of filamentous growth phenotypes can result from combinatorial effects of multiple mutations and by loss of different regulators of the response. The alleles identified here expand the connections surrounding MAPK pathway regulation and reveal new features of proteins that function in the signaling cascade.
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Affiliation(s)
- Atindra N Pujari
- Department of Biological Sciences, University at Buffalo, Buffalo, NY 14260, USA
| | - Paul J Cullen
- Department of Biological Sciences, University at Buffalo, Buffalo, NY 14260, USA
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2
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Piña F, Yan B, Hu J, Niwa M. Reticulons bind sphingolipids to activate the endoplasmic reticulum cell cycle checkpoint, the ER surveillance pathway. Cell Rep 2023; 42:113403. [PMID: 37979174 DOI: 10.1016/j.celrep.2023.113403] [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: 09/21/2021] [Revised: 12/09/2022] [Accepted: 10/23/2023] [Indexed: 11/20/2023] Open
Abstract
The inheritance of a functional endoplasmic reticulum (ER) is ensured by the ER stress surveillance (ERSU) pathway. Here, we made the unexpected discovery that reticulon 1 (Rtn1) and Yop1, well-known ER-curvature-generating proteins, each possess two sphingolipid-binding motifs within their transmembrane domains and that these motifs recognize the ER-stress-induced sphingolipid phytosphingosine (PHS), resulting in an ER inheritance block. Upon binding PHS, Rtn1/Yop1 accumulate on the ER tubule, poised to enter the emerging daughter cell, and cause its misdirection to the bud scars (i.e., previous cell division sites). Amino acid changes in the conserved PHS-binding motifs preclude Rtn1 or Yop1 from binding PHS and diminish their enrichment on the tubular ER, ultimately preventing the ER-stress-induced inheritance block. Conservation of these sphingolipid-binding motifs in human reticulons suggests that sphingolipid binding to Rtn1 and Yop1 represents an evolutionarily conserved mechanism that enables cells to respond to ER stress.
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Affiliation(s)
- Francisco Piña
- Division of Biological Sciences, Molecular Biology Section, University of California, San Diego, NSB#1, Rm. 5328, 9500 Gilman Drive, San Diego, CA 92093-0377, USA
| | - Bing Yan
- Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Rm. 6210, Chaoyang District, Beijing 100101, China
| | - Junjie Hu
- Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Rm. 6210, Chaoyang District, Beijing 100101, China
| | - Maho Niwa
- Division of Biological Sciences, Molecular Biology Section, University of California, San Diego, NSB#1, Rm. 5328, 9500 Gilman Drive, San Diego, CA 92093-0377, USA.
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3
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Pujari AN, Cullen PJ. Modulators of MAPK pathway activity during filamentous growth in Saccharomyces cerevisiae. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.22.573138. [PMID: 38187743 PMCID: PMC10769413 DOI: 10.1101/2023.12.22.573138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
Mitogen-activated protein kinase (MAPK) pathways control the response to intrinsic and extrinsic stimuli. In the budding yeast Saccharomyces cerevisiae, cells undergo filamentous growth, which is regulated by the fMAPK pathway. To better understand the regulation of the fMAPK pathway, a genetic screen was performed to identify spontaneous mutants with elevated activity of an fMAPK-pathway dependent growth reporter (ste4 FUS1-HIS3). In total, 159 mutants were isolated and analyzed by secondary screens for invasive growth by the plate-washing assay, and filament formation by microscopy. Thirty-two mutants were selected for whole-genome sequencing, which identified new alleles in genes encoding known regulators of the fMAPK pathway. These included gain-of-function alleles in STE11, which encodes the MAPKKK, as well as loss-of-function alleles in KSS1, which encodes the MAP kinase, and RGA1, which encodes a GTPase activating protein (GAP) for CDC42. New alleles in previously identified pathway modulators were also uncovered in ALY1, AIM44, RCK2, IRA2, REG1 and in genes that regulate protein folding (KAR2), glycosylation (MNN4), and turnover (BLM10). C-terminal truncations in the transcription factor Ste12p were also uncovered that resulted in elevated reporter activity, presumably identifying an inhibitory domain in the C-terminus of the protein. We also show that a wide variety of filamentous growth phenotypes result from mutations in different regulators of the response. The alleles identified here expand the connections surrounding MAPK pathway regulation and reveal new features of proteins that function in the signaling cascade.
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Affiliation(s)
- Atindra N. Pujari
- Department of Biological Sciences, University at Buffalo, Buffalo, New York 14260
| | - Paul J. Cullen
- Department of Biological Sciences, University at Buffalo, Buffalo, New York 14260
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4
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González B, Mirzaei M, Basu S, Pujari AN, Vandermeulen MD, Prabhakar A, Cullen PJ. Turnover and bypass of p21-activated kinase during Cdc42-dependent MAPK signaling in yeast. J Biol Chem 2023; 299:105297. [PMID: 37774975 PMCID: PMC10641623 DOI: 10.1016/j.jbc.2023.105297] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 08/10/2023] [Accepted: 08/12/2023] [Indexed: 10/01/2023] Open
Abstract
Mitogen-activated protein kinase (MAPK) pathways regulate multiple cellular behaviors, including the response to stress and cell differentiation, and are highly conserved across eukaryotes. MAPK pathways can be activated by the interaction between the small GTPase Cdc42p and the p21-activated kinase (Ste20p in yeast). By studying MAPK pathway regulation in yeast, we recently found that the active conformation of Cdc42p is regulated by turnover, which impacts the activity of the pathway that regulates filamentous growth (fMAPK). Here, we show that Ste20p is regulated in a similar manner and is turned over by the 26S proteasome. This turnover did not occur when Ste20p was bound to Cdc42p, which presumably stabilized the protein to sustain MAPK pathway signaling. Although Ste20p is a major component of the fMAPK pathway, genetic approaches here identified a Ste20p-independent branch of signaling. Ste20p-independent signaling partially required the fMAPK pathway scaffold and Cdc42p-interacting protein, Bem4p, while Ste20p-dependent signaling required the 14-3-3 proteins, Bmh1p and Bmh2p. Interestingly, Ste20p-independent signaling was inhibited by one of the GTPase-activating proteins for Cdc42p, Rga1p, which unexpectedly dampened basal but not active fMAPK pathway activity. These new regulatory features of the Rho GTPase and p21-activated kinase module may extend to related pathways in other systems.
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Affiliation(s)
- Beatriz González
- Department of Biological Sciences, State University of New York at Buffalo, Buffalo, New York, USA
| | - Mahnoosh Mirzaei
- Department of Biological Sciences, State University of New York at Buffalo, Buffalo, New York, USA
| | - Sukanya Basu
- Department of Biological Sciences, State University of New York at Buffalo, Buffalo, New York, USA
| | - Atindra N Pujari
- Department of Biological Sciences, State University of New York at Buffalo, Buffalo, New York, USA
| | - Matthew D Vandermeulen
- Department of Biological Sciences, State University of New York at Buffalo, Buffalo, New York, USA
| | - Aditi Prabhakar
- Department of Biological Sciences, State University of New York at Buffalo, Buffalo, New York, USA
| | - Paul J Cullen
- Department of Biological Sciences, State University of New York at Buffalo, Buffalo, New York, USA.
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5
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Ng K, Hirani N, Bland T, Borrego-Pinto J, Wagner S, Kreysing M, Goehring NW. Cleavage furrow-directed cortical flows bias PAR polarization pathways to link cell polarity to cell division. Curr Biol 2023; 33:4298-4311.e6. [PMID: 37729912 DOI: 10.1016/j.cub.2023.08.076] [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: 01/24/2023] [Revised: 07/13/2023] [Accepted: 08/24/2023] [Indexed: 09/22/2023]
Abstract
During development, the conserved PAR polarity network is continuously redeployed, requiring that it adapt to changing cellular contexts and environmental cues. In the early C. elegans embryo, polarity shifts from being a cell-autonomous process in the zygote to one that must be coordinated between neighbors as the embryo becomes multicellular. Here, we sought to explore how the PAR network adapts to this shift in the highly tractable C. elegans germline P lineage. We find that although P lineage blastomeres exhibit a distinct pattern of polarity emergence compared with the zygote, the underlying mechanochemical processes that drive polarity are largely conserved. However, changes in the symmetry-breaking cues of P lineage blastomeres ensure coordination of their polarity axis with neighboring cells. Specifically, we show that furrow-directed cortical flows associated with cytokinesis of the zygote induce symmetry breaking in the germline blastomere P1 by transporting PAR-3 into the nascent cell contact. This pool of PAR-3 then biases downstream PAR polarization pathways to establish the polarity axis of P1 with respect to the position of its anterior sister, AB. Thus, our data suggest that cytokinesis itself induces symmetry breaking through the advection of polarity proteins by furrow-directed flows. By directly linking cell polarity to cell division, furrow-directed cortical flows could be a general mechanism to ensure proper organization of cell polarity within actively dividing systems.
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Affiliation(s)
- KangBo Ng
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK; Institute for the Physics of Living Systems, University College London, London WC1E 6BT, UK
| | - Nisha Hirani
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Tom Bland
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK; Institute for the Physics of Living Systems, University College London, London WC1E 6BT, UK
| | | | - Susan Wagner
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany; Institute of Biological and Chemical Systems, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Moritz Kreysing
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany; Institute of Biological and Chemical Systems, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Nathan W Goehring
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK; Institute for the Physics of Living Systems, University College London, London WC1E 6BT, UK.
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6
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Gonz Lez B, Mirzaei M, Basu S, Prabhakar A, Cullen PJ. New Features Surrounding the Cdc42-Ste20 Module that Regulates MAP Kinase Signaling in Yeast. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.28.530426. [PMID: 36909494 PMCID: PMC10002611 DOI: 10.1101/2023.02.28.530426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/06/2023]
Abstract
Mitogen-activated protein kinase (MAPK) pathways regulate multiple cellular responses, including the response to stress and cell differentiation, and are highly conserved across eukaryotes from yeast to humans. In yeast, the canonical activation of several MAPK pathways includes the interaction of the small GTPase Cdc42p with the p21-activated kinase (PAK) Ste20p. We recently found that the active conformation of Cdc42p is regulated by turnover, which impacts the activity of the pathway that regulates filamentous growth (fMAPK). Here, we show that Ste20p is turned over by the 26S proteasome. Ste20p was stabilized when bound to Cdc42p, presumably to sustain MAPK pathway signaling. Ste20p is a major conduit by which signals flow through the fMAPK pathway; however, by genetic approaches we also identified a Ste20p-independent branch of the fMAPK pathway. Ste20p-dependent signaling required the 14-3-3 proteins, Bmh1p and Bmh2p, while Ste20p-independent signaling required the fMAPK pathway adaptor and Cdc42p-interacting protein, Bem4p. Ste20p-independent signaling was inhibited by one of the GTPase-activating proteins for Cdc42p in the fMAPK pathway, Rga1p, which also dampened basal but not active fMAPK pathway activity. Finally, the polarity adaptor and Cdc42p-interacting protein, Bem1p, which also regulates the fMAPK pathway, interacts with the tetra-span protein Sho1p, connecting a sensor at the plasma membrane to a protein that regulates the GTPase module. Collectively, these data reveal new regulatory features surrounding a Rho-PAK module that may extend to other pathways that control cell differentiation.
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7
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Kang PJ, Mullner R, Li H, Hansford D, Shen HW, Park HO. Upregulation of the Cdc42 GTPase limits the replicative lifespan of budding yeast. Mol Biol Cell 2022; 33:br5. [PMID: 35044837 PMCID: PMC9250358 DOI: 10.1091/mbc.e21-04-0208] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Cdc42, a conserved Rho GTPase, plays a central role in polarity establishment in yeast and animals. Cell polarity is critical for asymmetric cell division, and asymmetric cell division underlies replicative aging of budding yeast. Yet how Cdc42 and other polarity factors impact life span is largely unknown. Here we show by live-cell imaging that the active Cdc42 level is sporadically elevated in wild type during repeated cell divisions but rarely in the long-lived bud8 deletion cells. We find a novel Bud8 localization with cytokinesis remnants, which also recruit Rga1, a Cdc42 GTPase activating protein. Genetic analyses and live-cell imaging suggest that Rga1 and Bud8 oppositely impact life span likely by modulating active Cdc42 levels. An rga1 mutant, which has a shorter life span, dies at the unbudded state with a defect in polarity establishment. Remarkably, Cdc42 accumulates in old cells, and its mild overexpression accelerates aging with frequent symmetric cell divisions, despite no harmful effects on young cells. Our findings implicate that the interplay among these positive and negative polarity factors limits the life span of budding yeast.
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Affiliation(s)
- Pil Jung Kang
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210, USA
| | - Rachel Mullner
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210, USA
| | - Haoyu Li
- Department of Computer Science and Engineering, The Ohio State University, Columbus, OH 43210, USA
| | - Derek Hansford
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH 43210, USA
| | - Han-Wei Shen
- Department of Computer Science and Engineering, The Ohio State University, Columbus, OH 43210, USA
| | - Hay-Oak Park
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210, USA
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8
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Fung JJ, Blöcher-Juárez K, Khmelinskii A. High-Throughput Analysis of Protein Turnover with Tandem Fluorescent Protein Timers. Methods Mol Biol 2022; 2378:85-100. [PMID: 34985695 DOI: 10.1007/978-1-0716-1732-8_6] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Tandem fluorescent protein timers (tFTs) are versatile reporters of protein dynamics. A tFT consists of two fluorescent proteins with different maturation kinetics and provides a ratiometric readout of protein age, which can be exploited to follow intracellular trafficking, inheritance and turnover of tFT-tagged proteins. Here, we detail a protocol for high-throughput analysis of protein turnover with tFTs in yeast using fluorescence measurements of ordered colony arrays. We describe guidelines on optimization of experimental design with regard to the layout of colony arrays, growth conditions, and instrument choice. Combined with semi-automated genetic crossing using synthetic genetic array (SGA) methodology and high-throughput protein tagging with SWAp-Tag (SWAT) libraries, this approach can be used to compare protein turnover across the proteome and to identify regulators of protein turnover genome-wide.
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Affiliation(s)
- Jia Jun Fung
- Institute of Molecular Biology (IMB), Mainz, Germany
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9
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Kocakaplan D, Karabürk H, Dilege C, Kirdök I, Bektas SN, Caydasi AK. Protein phosphatase 1 in association with Bud14 inhibits mitotic exit in Saccharomyces cerevisiae. eLife 2021; 10:72833. [PMID: 34633288 PMCID: PMC8577847 DOI: 10.7554/elife.72833] [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: 08/05/2021] [Accepted: 10/08/2021] [Indexed: 11/18/2022] Open
Abstract
Mitotic exit in budding yeast is dependent on correct orientation of the mitotic spindle along the cell polarity axis. When accurate positioning of the spindle fails, a surveillance mechanism named the spindle position checkpoint (SPOC) prevents cells from exiting mitosis. Mutants with a defective SPOC become multinucleated and lose their genomic integrity. Yet, a comprehensive understanding of the SPOC mechanism is missing. In this study, we identified the type 1 protein phosphatase, Glc7, in association with its regulatory protein Bud14 as a novel checkpoint component. We further showed that Glc7-Bud14 promotes dephosphorylation of the SPOC effector protein Bfa1. Our results suggest a model in which two mechanisms act in parallel for a robust checkpoint response: first, the SPOC kinase Kin4 isolates Bfa1 away from the inhibitory kinase Cdc5, and second, Glc7-Bud14 dephosphorylates Bfa1 to fully activate the checkpoint effector.
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Affiliation(s)
- Dilara Kocakaplan
- Department of Molecular Biology and Genetics, Koç University, Istanbul, Turkey
| | - Hüseyin Karabürk
- Department of Molecular Biology and Genetics, Koç University, Istanbul, Turkey
| | - Cansu Dilege
- Department of Molecular Biology and Genetics, Koç University, Istanbul, Turkey
| | - Idil Kirdök
- Department of Molecular Biology and Genetics, Koç University, Istanbul, Turkey
| | - Seyma Nur Bektas
- Department of Molecular Biology and Genetics, Koç University, Istanbul, Turkey
| | - Ayse Koca Caydasi
- Department of Molecular Biology and Genetics, Koç University, Istanbul, Turkey
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10
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Durán DC, Hernández CA, Suesca E, Acevedo R, Acosta IM, Forero DA, Rozo FE, Pedraza JM. Slipstreaming Mother Machine: A Microfluidic Device for Single-Cell Dynamic Imaging of Yeast. MICROMACHINES 2020; 12:mi12010004. [PMID: 33374994 PMCID: PMC7822021 DOI: 10.3390/mi12010004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 12/08/2020] [Accepted: 12/14/2020] [Indexed: 02/07/2023]
Abstract
The yeast Saccharomyces cerevisiae is one of the most basic model organisms for studies of aging and other phenomena such as division strategies. These organisms have been typically studied with the use of microfluidic devices to keep cells trapped while under a flow of fresh media. However, all of the existing devices trap cells mechanically, subjecting them to pressures that may affect cell physiology. There is evidence mechanical pressure affects growth rate and the movement of intracellular components, so it is quite possible that it affects other physiological aspects such as aging. To allow studies with the lowest influence of mechanical pressure, we designed and fabricated a device that takes advantage of the slipstreaming effect. In slipstreaming, moving fluids that encounter a barrier flow around it forming a pressure gradient behind it. We trap mother cells in this region and force daughter cells to be in the negative pressure gradient region so that they are taken away by the flow. Additionally, this device can be fabricated using low resolution lithography techniques, which makes it less expensive than devices that require photolithography masks with resolution under 5 µm. With this device, it is possible to measure some of the most interesting aspects of yeast dynamics such as growth rates and Replicative Life Span. This device should allow future studies to eliminate pressure bias as well as extending the range of labs that can do these types of measurements.
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Affiliation(s)
- David C. Durán
- Laboratorio de Biofísica, Departamento de Física, Universidad de los Andes, Bogotá 111711, Colombia; (E.S.); (R.A.); (I.M.A.); (D.A.F.); (F.E.R.)
- Correspondence: (D.C.D.); (J.M.P.); Tel.: +57-1-3394949 (ext. 5179 (COL)) (J.M.P.)
| | - César A. Hernández
- Centro de Microelectrónica, Departamento de Ingeniería Eléctrica y Electrónica, Universidad de los Andes CMUA, Bogotá 111711, Colombia;
| | - Elizabeth Suesca
- Laboratorio de Biofísica, Departamento de Física, Universidad de los Andes, Bogotá 111711, Colombia; (E.S.); (R.A.); (I.M.A.); (D.A.F.); (F.E.R.)
| | - Rubén Acevedo
- Laboratorio de Biofísica, Departamento de Física, Universidad de los Andes, Bogotá 111711, Colombia; (E.S.); (R.A.); (I.M.A.); (D.A.F.); (F.E.R.)
| | - Ivón M. Acosta
- Laboratorio de Biofísica, Departamento de Física, Universidad de los Andes, Bogotá 111711, Colombia; (E.S.); (R.A.); (I.M.A.); (D.A.F.); (F.E.R.)
- Proyecto Curricular Licenciatura en Física, Facultad de Ciencias y Educación, Universidad Distrital Francisco José de Caldas, Bogotá 110311, Colombia
| | - Diana A. Forero
- Laboratorio de Biofísica, Departamento de Física, Universidad de los Andes, Bogotá 111711, Colombia; (E.S.); (R.A.); (I.M.A.); (D.A.F.); (F.E.R.)
- Proyecto Curricular Licenciatura en Física, Facultad de Ciencias y Educación, Universidad Distrital Francisco José de Caldas, Bogotá 110311, Colombia
| | - Francisco E. Rozo
- Laboratorio de Biofísica, Departamento de Física, Universidad de los Andes, Bogotá 111711, Colombia; (E.S.); (R.A.); (I.M.A.); (D.A.F.); (F.E.R.)
- Proyecto Curricular Licenciatura en Física, Facultad de Ciencias y Educación, Universidad Distrital Francisco José de Caldas, Bogotá 110311, Colombia
| | - Juan M. Pedraza
- Laboratorio de Biofísica, Departamento de Física, Universidad de los Andes, Bogotá 111711, Colombia; (E.S.); (R.A.); (I.M.A.); (D.A.F.); (F.E.R.)
- Correspondence: (D.C.D.); (J.M.P.); Tel.: +57-1-3394949 (ext. 5179 (COL)) (J.M.P.)
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11
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Bheda P, Aguilar-Gómez D, Kukhtevich I, Becker J, Charvin G, Kirmizis A, Schneider R. Microfluidics for single-cell lineage tracking over time to characterize transmission of phenotypes in Saccharomyces cerevisiae. STAR Protoc 2020; 1:100228. [PMID: 33377118 PMCID: PMC7757727 DOI: 10.1016/j.xpro.2020.100228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The budding yeast Saccharomyces cerevisiae is an excellent model organism to dissect the maintenance and inheritance of phenotypes due to its asymmetric division. This requires following individual cells over time as they go through divisions to define pedigrees. Here, we provide a detailed protocol for collecting and analyzing time-lapse imaging data of yeast cells. The microfluidics protocol can achieve improved time resolution for single-cell tracking to enable characterization of maintenance and inheritance of phenotypes. For complete details on the use and execution of this protocol, please refer to Bheda et al. (2020a).
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Affiliation(s)
- Poonam Bheda
- Institute of Functional Epigenetics, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | | | - Igor Kukhtevich
- Institute of Functional Epigenetics, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Johannes Becker
- Institute of Bioengineering, School of Engineering, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Gilles Charvin
- Development and Stem Cells, IGBMC, 67400 Illkirch, France
| | - Antonis Kirmizis
- Department of Biological Sciences, University of Cyprus, 2109 Nicosia, Cyprus
| | - Robert Schneider
- Institute of Functional Epigenetics, Helmholtz Zentrum München, 85764 Neuherberg, Germany
- German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany
- Faculty of Biology, Ludwig-Maximilians Universität München, 80333 Munich, Germany
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12
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Grinhagens S, Dünkler A, Wu Y, Rieger L, Brenner P, Gronemeyer T, Mulaw MA, Johnsson N. A time-resolved interaction analysis of Bem1 reconstructs the flow of Cdc42 during polar growth. Life Sci Alliance 2020; 3:e202000813. [PMID: 32737079 PMCID: PMC7409549 DOI: 10.26508/lsa.202000813] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 07/20/2020] [Accepted: 07/21/2020] [Indexed: 12/16/2022] Open
Abstract
Cdc42 organizes cellular polarity and directs the formation of cellular structures in many organisms. By locating Cdc24, the source of active Cdc42, to the growing front of the yeast cell, the scaffold protein Bem1, is instrumental in shaping the cellular gradient of Cdc42. This gradient instructs bud formation, bud growth, or cytokinesis through the actions of a diverse set of effector proteins. To address how Bem1 participates in these transformations, we systematically tracked its protein interactions during one cell cycle to define the ensemble of Bem1 interaction states for each cell cycle stage. Mutants of Bem1 that interact with only a discrete subset of the interaction partners allowed to assign specific functions to different interaction states and identified the determinants for their cellular distributions. The analysis characterizes Bem1 as a cell cycle-specific shuttle that distributes active Cdc42 from its source to its effectors. It further suggests that Bem1 might convert the PAKs Cla4 and Ste20 into their active conformations.
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Affiliation(s)
- Sören Grinhagens
- Department of Biology, Institute of Molecular Genetics and Cell Biology, Ulm University, Ulm, Germany
| | - Alexander Dünkler
- Department of Biology, Institute of Molecular Genetics and Cell Biology, Ulm University, Ulm, Germany
| | - Yehui Wu
- Department of Biology, Institute of Molecular Genetics and Cell Biology, Ulm University, Ulm, Germany
| | - Lucia Rieger
- Department of Biology, Institute of Molecular Genetics and Cell Biology, Ulm University, Ulm, Germany
| | - Philipp Brenner
- Department of Biology, Institute of Molecular Genetics and Cell Biology, Ulm University, Ulm, Germany
| | - Thomas Gronemeyer
- Department of Biology, Institute of Molecular Genetics and Cell Biology, Ulm University, Ulm, Germany
| | - Medhanie A Mulaw
- Comprehensive Cancer Center Ulm, Institute of Experimental Cancer Research, Ulm University, Ulm, Germany
| | - Nils Johnsson
- Department of Biology, Institute of Molecular Genetics and Cell Biology, Ulm University, Ulm, Germany
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13
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Florian MC, Leins H, Gobs M, Han Y, Marka G, Soller K, Vollmer A, Sakk V, Nattamai KJ, Rayes A, Zhao X, Setchell K, Mulaw M, Wagner W, Zheng Y, Geiger H. Inhibition of Cdc42 activity extends lifespan and decreases circulating inflammatory cytokines in aged female C57BL/6 mice. Aging Cell 2020; 19:e13208. [PMID: 32755011 PMCID: PMC7511875 DOI: 10.1111/acel.13208] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 04/27/2020] [Accepted: 07/07/2020] [Indexed: 12/12/2022] Open
Abstract
Cdc42 is a small RhoGTPase regulating multiple functions in eukaryotic cells. The activity of Cdc42 is significantly elevated in several tissues of aged mice, while the Cdc42 gain‐of‐activity mouse model presents with a premature aging‐like phenotype and with decreased lifespan. These data suggest a causal connection between elevated activity of Cdc42, aging, and reduced lifespan. Here, we demonstrate that systemic treatment of aged (75‐week‐old) female C57BL/6 mice with a Cdc42 activity‐specific inhibitor (CASIN) for 4 consecutive days significantly extends average and maximum lifespan. Moreover, aged CASIN‐treated animals displayed a youthful level of the aging‐associated cytokines IL‐1β, IL‐1α, and INFγ in serum and a significantly younger epigenetic clock as based on DNA methylation levels in blood cells. Overall, our data show that systemic administration of CASIN to reduce Cdc42 activity in aged mice extends murine lifespan.
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Affiliation(s)
- Maria Carolina Florian
- Program of Regenerative Medicine, IDIBELL, Barcelona, Spain.,Institute of Molecular Medicine and Stem Cell Aging, Ulm University, Ulm, Germany
| | - Hanna Leins
- Institute of Molecular Medicine and Stem Cell Aging, Ulm University, Ulm, Germany
| | - Michael Gobs
- Helmholtz-Institute for Biomedical Engineering, Stem Cell Biology and Cellular Engineering, RWTH Aachen University Medical School, Aachen, Germany
| | - Yang Han
- Helmholtz-Institute for Biomedical Engineering, Stem Cell Biology and Cellular Engineering, RWTH Aachen University Medical School, Aachen, Germany
| | - Gina Marka
- Institute of Molecular Medicine and Stem Cell Aging, Ulm University, Ulm, Germany
| | - Karin Soller
- Institute of Molecular Medicine and Stem Cell Aging, Ulm University, Ulm, Germany
| | - Angelika Vollmer
- Institute of Molecular Medicine and Stem Cell Aging, Ulm University, Ulm, Germany
| | - Vadim Sakk
- Institute of Molecular Medicine and Stem Cell Aging, Ulm University, Ulm, Germany
| | - Kalpana J Nattamai
- Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio, USA
| | - Ahmad Rayes
- Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio, USA
| | - Xueheng Zhao
- Division of Pathology, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio, USA
| | - Kenneth Setchell
- Division of Pathology, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio, USA
| | - Medhanie Mulaw
- Institute of Experimental Cancer Research, Medical Faculty, University of Ulm, Ulm, Germany
| | - Wolfgang Wagner
- Helmholtz-Institute for Biomedical Engineering, Stem Cell Biology and Cellular Engineering, RWTH Aachen University Medical School, Aachen, Germany
| | - Yi Zheng
- Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio, USA
| | - Hartmut Geiger
- Institute of Molecular Medicine and Stem Cell Aging, Ulm University, Ulm, Germany
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14
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Chollet J, Dünkler A, Bäuerle A, Vivero-Pol L, Mulaw MA, Gronemeyer T, Johnsson N. Cdc24 interacts with septins to create a positive feedback loop during bud site assembly in yeast. J Cell Sci 2020; 133:jcs240283. [PMID: 32327559 DOI: 10.1242/jcs.240283] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 04/08/2020] [Indexed: 01/04/2023] Open
Abstract
Yeast cells select the position of their new bud at the beginning of each cell cycle. The recruitment of septins to this prospective bud site is one of the critical events in a complex assembly pathway that culminates in the outgrowth of a new daughter cell. During recruitment, septin rods follow the high concentration of Cdc42GTP that is generated by the focused localization of the Cdc42 guanine-nucleotide-exchange factor Cdc24. We show that, shortly before budding, Cdc24 not only activates Cdc42 but also transiently interacts with Cdc11, the septin subunit that caps both ends of the septin rods. Mutations in Cdc24 that reduce affinity to Cdc11 impair septin recruitment and decrease the stability of the polarity patch. The interaction between septins and Cdc24 thus reinforces bud assembly at sites where septin structures are formed. Once the septins polymerize to form the septin ring, Cdc24 is found at the cortex of the bud and directs further outgrowth from this position.
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Affiliation(s)
- Julian Chollet
- Institute of Molecular Genetics and Cell Biology, Department of Biology, Ulm University, James-Franck-Ring N27, D-89081 Ulm, Germany
| | - Alexander Dünkler
- Institute of Molecular Genetics and Cell Biology, Department of Biology, Ulm University, James-Franck-Ring N27, D-89081 Ulm, Germany
| | - Anne Bäuerle
- Institute of Molecular Genetics and Cell Biology, Department of Biology, Ulm University, James-Franck-Ring N27, D-89081 Ulm, Germany
| | - Laura Vivero-Pol
- Institute of Molecular Genetics and Cell Biology, Department of Biology, Ulm University, James-Franck-Ring N27, D-89081 Ulm, Germany
| | - Medhanie A Mulaw
- Comprehensive Cancer Center Ulm, Institute of Experimental Cancer Research, Ulm University, James-Franck-Ring N27, D-89081 Ulm, Germany
| | - Thomas Gronemeyer
- Institute of Molecular Genetics and Cell Biology, Department of Biology, Ulm University, James-Franck-Ring N27, D-89081 Ulm, Germany
| | - Nils Johnsson
- Institute of Molecular Genetics and Cell Biology, Department of Biology, Ulm University, James-Franck-Ring N27, D-89081 Ulm, Germany
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15
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Cell size sets the diameter of the budding yeast contractile ring. Nat Commun 2020; 11:2952. [PMID: 32528053 PMCID: PMC7289848 DOI: 10.1038/s41467-020-16764-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 05/21/2020] [Indexed: 01/02/2023] Open
Abstract
The formation and maintenance of subcellular structures and organelles with a well-defined size is a key requirement for cell function, yet our understanding of the underlying size control mechanisms is limited. While budding yeast cell polarization and subsequent assembly of a septin ring at the site of bud formation has been successfully used as a model for biological self-assembly processes, the mechanisms that set the size of the septin ring at the bud neck are unknown. Here, we use live-cell imaging and genetic manipulation of cell volume to show that the septin ring diameter increases with cell volume. This cell-volume-dependence largely accounts for modulations of ring size due to changes in ploidy and genetic manipulation of cell polarization. Our findings suggest that the ring diameter is set through the dynamic interplay of septin recruitment and Cdc42 polarization, establishing it as a model for size homeostasis of self-assembling organelles. Budding yeast cell polarization is known to self-assemble, but it is still not clear what controls the size of the resulting septin ring. Here the authors show that the septin ring diameter is set by cell volume, ensuring that larger cells have larger rings.
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16
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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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17
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Prabhakar A, Chow J, Siegel AJ, Cullen PJ. Regulation of intrinsic polarity establishment by a differentiation-type MAPK pathway in S. cerevisiae. J Cell Sci 2020; 133:jcs241513. [PMID: 32079658 PMCID: PMC7174846 DOI: 10.1242/jcs.241513] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Accepted: 02/12/2020] [Indexed: 01/15/2023] Open
Abstract
All cells establish and maintain an axis of polarity that is critical for cell shape and progression through the cell cycle. A well-studied example of polarity establishment is bud emergence in the yeast Saccharomyces cerevisiae, which is controlled by the Rho GTPase Cdc42p. The prevailing view of bud emergence does not account for regulation by extrinsic cues. Here, we show that the filamentous growth mitogen activated protein kinase (fMAPK) pathway regulates bud emergence under nutrient-limiting conditions. The fMAPK pathway regulated the expression of polarity targets including the gene encoding a direct effector of Cdc42p, Gic2p. The fMAPK pathway also stimulated GTP-Cdc42p levels, which is a critical determinant of polarity establishment. The fMAPK pathway activity was spatially restricted to bud sites and active during the period of the cell cycle leading up to bud emergence. Time-lapse fluorescence microscopy showed that the fMAPK pathway stimulated the rate of bud emergence during filamentous growth. Unregulated activation of the fMAPK pathway induced multiple rounds of symmetry breaking inside the growing bud. Collectively, our findings identify a new regulatory aspect of bud emergence that sensitizes this essential cellular process to external cues.
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Affiliation(s)
- Aditi Prabhakar
- Department of Biological Sciences, University at Buffalo, Buffalo, NY 14260-1300, USA
| | - Jacky Chow
- Department of Biological Sciences, University at Buffalo, Buffalo, NY 14260-1300, USA
| | - Alan J Siegel
- Department of Biological Sciences, University at Buffalo, Buffalo, NY 14260-1300, USA
| | - Paul J Cullen
- Department of Biological Sciences, University at Buffalo, Buffalo, NY 14260-1300, USA
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18
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Mitotic and pheromone-specific intrinsic polarization cues interfere with gradient sensing in Saccharomyces cerevisiae. Proc Natl Acad Sci U S A 2020; 117:6580-6589. [PMID: 32152126 DOI: 10.1073/pnas.1912505117] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Polarity decisions are central to many processes, including mitosis and chemotropism. In Saccharomyces cerevisiae, budding and mating projection (MP) formation use an overlapping system of cortical landmarks that converges on the small G protein Cdc42. However, pheromone-gradient sensing must override the Rsr1-dependent internal polarity cues used for budding. Using this model system, we asked what happens when intrinsic and extrinsic spatial cues are not aligned. Is there competition, or collaboration? By live-cell microscopy and microfluidics techniques, we uncovered three previously overlooked features of this signaling system. First, the cytokinesis-associated polarization patch serves as a polarity landmark independently of all known cues. Second, the Rax1-Rax2 complex functions as a pheromone-promoted polarity cue in the distal pole of the cells. Third, internal cues remain active during pheromone-gradient tracking and can interfere with this process, biasing the location of MPs. Yeast defective in internal-cue utilization align significantly better than wild type with artificially generated pheromone gradients.
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19
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Xu M, Liu Y, Huang Y, Wang J, Yan J, Zhang L, Zhang C. Re-exploring the core genes and modules in the human frontal cortex during chronological aging: insights from network-based analysis of transcriptomic studies. Aging (Albany NY) 2019; 10:2816-2831. [PMID: 30341976 PMCID: PMC6224233 DOI: 10.18632/aging.101589] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Accepted: 10/04/2018] [Indexed: 11/25/2022]
Abstract
Frontal cortical dysfunction is a fundamental pathology contributing to age-associated behavioral and cognitive deficits that predispose older adults to neurodegenerative diseases. It is established that aging increases the risk of frontal cortical dysfunction; however, the underlying molecular mechanism remains elusive. Here, we used an integrative meta-analysis to combine five frontal cortex microarray studies with a combined sample population of 161 younger and 155 older individuals. A network-based analysis was used to describe an outline of human frontal cortical aging to identify core genes whose expression changes with age and to reveal the interrelationships among these genes. We found that histone deacetylase 1 (HDAC1) and YES proto-oncogene 1 (YES1) are the two most upregulated genes, while cell division cycle 42 (CDC42) is the central regulatory gene decreased in the aged human frontal cortex. Quantitative PCR assays revealed corresponding changes in frontal cortical Hdac1, Yes1 and Cdc42 mRNA levels in an established aging mouse model. Moreover, analysis of the GSE48350 dataset confirmed similar changes in HDAC1, CDC42 and YES1 expression in Alzheimer's disease, thereby providing a molecular connection between aging and Alzheimer's disease (AD). This framework of network-based analysis could provide novel strategies for detecting and monitoring aging in the brain.
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Affiliation(s)
- Mulin Xu
- Department of Geriatrics, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, P.R. China
| | - Yu Liu
- Department of Geriatrics, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, P.R. China.,Department of Internal Medicine, University of Utah, Salt Lake City, Utah 84112, U.S.A
| | - Yi Huang
- Department of Geriatrics, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, P.R. China
| | - Jinli Wang
- Department of Geriatrics, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, P.R. China
| | - Jinhua Yan
- Department of Geriatrics, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, P.R. China
| | - Le Zhang
- Department of Geriatrics, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, P.R. China
| | - Cuntai Zhang
- Department of Geriatrics, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, P.R. China
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20
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Transfer of the Septin Ring to Cytokinetic Remnants in ER Stress Directs Age-Sensitive Cell-Cycle Re-entry. Dev Cell 2019; 51:173-191.e5. [PMID: 31564614 DOI: 10.1016/j.devcel.2019.08.017] [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: 11/17/2018] [Revised: 05/19/2019] [Accepted: 08/23/2019] [Indexed: 02/06/2023]
Abstract
During cell division, the inheritance of a functional endoplasmic reticulum (ER) is ensured by the endoplasmic reticulum stress surveillance (ERSU) pathway. Activation of ERSU causes the septin ring to mislocalize, which blocks ER inheritance and cytokinesis. Here, we uncover that the septin ring in fact translocates to previously utilized cell division sites called cytokinetic remnants (CRMs). This unconventional translocation requires Nba1, a negative polarity regulator that normally prevents repolarization and re-budding at CRMs. Furthermore, septin ring translocation relies on the recruitment and activation of a key ERSU component Slt2 by Bem1, without activating Cdc42. Failure to transfer all septin subunits to CRMs delays the cell's ability to re-enter the cell cycle when ER homeostasis is restored and hinders cell growth after ER stress recovery. Thus, these deliberate but unprecedented rearrangements of cell polarity factors during ER stress safeguard cell survival and the timely cell-cycle re-entry upon ER stress recovery.
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21
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Estrem C, Moore JK. Astral microtubule forces alter nuclear organization and inhibit DNA repair in budding yeast. Mol Biol Cell 2019; 30:2000-2013. [PMID: 31067146 PMCID: PMC6727761 DOI: 10.1091/mbc.e18-12-0808] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Dividing cells must balance the maintenance of genome integrity with the generation of cytoskeletal forces that control chromosome position. In this study, we investigate how forces on astral microtubules impact the genome during cell division by using live-cell imaging of the cytoskeleton, chromatin, and DNA damage repair in budding yeast. Our results demonstrate that dynein-dependent forces on astral microtubules are propagated through the spindle during nuclear migration and when in excess can increase the frequency of double-stranded breaks (DSBs). Under these conditions, we find that homology-directed repair of DSBs is delayed, indicating antagonism between nuclear migration and the mechanism of homology-directed repair. These effects are partially rescued by mutants that weaken pericentric cohesion or mutants that decrease constriction on the nucleus as it moves through the bud neck. We propose that minimizing nuclear movement aids in finding a donor strand for homologous recombination.
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Affiliation(s)
- Cassi Estrem
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO 80045
| | - Jeffrey K Moore
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO 80045
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22
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Kubo K, Okada H, Shimamoto T, Kimori Y, Mizunuma M, Bi E, Ohnuki S, Ohya Y. Implications of maintenance of mother-bud neck size in diverse vital processes of Saccharomyces cerevisiae. Curr Genet 2019; 65:253-267. [PMID: 30066140 DOI: 10.1007/s00294-018-0872-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 07/17/2018] [Accepted: 07/25/2018] [Indexed: 11/25/2022]
Abstract
The mother-bud neck is defined as the boundary between the mother cell and bud in budding microorganisms, wherein sequential morphological events occur throughout the cell cycle. This study was designed to quantitatively investigate the morphology of the mother-bud neck in budding yeast Saccharomyces cerevisiae. Observation of yeast cells with time-lapse microscopy revealed an increase of mother-bud neck size through the cell cycle. After screening of yeast non-essential gene-deletion mutants with the image processing software CalMorph, we comprehensively identified 274 mutants with broader necks during S/G2 phase. Among these yeasts, we extensively analyzed 19 representative deletion mutants with defects in genes annotated to six gene ontology terms (polarisome, actin reorganization, endosomal tethering complex, carboxy-terminal domain protein kinase complex, DNA replication, and maintenance of DNA trinucleotide repeats). The representative broad-necked mutants exhibited calcofluor white sensitivity, suggesting defects in their cell walls. Correlation analysis indicated that maintenance of mother-bud neck size is important for cellular processes such as cell growth, system robustness, and replicative lifespan. We conclude that neck-size maintenance in budding yeast is regulated by numerous genes and has several aspects that are physiologically significant.
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Affiliation(s)
- Karen Kubo
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo, Kashiwa, Chiba, 277-8562, Japan
| | - Hiroki Okada
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104-6058, USA
| | - Takuya Shimamoto
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo, Kashiwa, Chiba, 277-8562, Japan
| | - Yoshitaka Kimori
- Department of Imaging Science, Center for Novel Science Initiatives, National Institutes of Natural Sciences, Okazaki, 444-8787, Japan
- Department of Management and Information Sciences, Faculty of Environmental and Information Sciences, Fukui University of Technology, Gakuen, Fukui City, Fukui, 910-8505, Japan
| | - Masaki Mizunuma
- Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, 739-8530, Japan
| | - Erfei Bi
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104-6058, USA
| | - Shinsuke Ohnuki
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo, Kashiwa, Chiba, 277-8562, Japan
| | - Yoshikazu Ohya
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo, Kashiwa, Chiba, 277-8562, Japan.
- AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory (OPERANDO-OIL), National Institute of Advanced Industrial Science and Technology (AIST), Kashiwa, Chiba, 277-8565, Japan.
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23
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Perez AM, Thorner J. Septin-associated proteins Aim44 and Nis1 traffic between the bud neck and the nucleus in the yeast Saccharomyces cerevisiae. Cytoskeleton (Hoboken) 2018; 76:15-32. [PMID: 30341817 PMCID: PMC6474838 DOI: 10.1002/cm.21500] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Revised: 09/25/2018] [Accepted: 10/10/2018] [Indexed: 12/20/2022]
Abstract
In budding yeast, a collar of septin filaments at the neck between a mother cell and its bud marks the incipient site for cell division and serves as a scaffold that recruits proteins required for proper spatial and temporal execution of cytokinesis. A set of interacting proteins that localize at or near the bud neck, including Aim44/Gps1, Nba1 and Nis1, also has been implicated in preventing Cdc42‐dependent bud site re‐establishment at the division site. We found that, at their endogenous level, Aim44 and Nis1 robustly localize sequentially at the septin collar. Strikingly, however, when overproduced, both proteins shift their subcellular distribution predominantly to the nucleus. Aim44 localizes with the inner nuclear envelope, as well as at the plasma membrane, whereas Nis1 accumulates within the nucleus, indicating that these proteins normally undergo nucleocytoplasmic shuttling. Of the 14 yeast karyopherins, Kap123/Yrb4 is the primary importin for Aim44, whereas several importins mediate Nis1 nuclear entry. Conversely, Kap124/Xpo1/Crm1 is the primary exportin for Nis1, whereas both Xpo1 and Cse1/Kap109 likely contribute to Aim44 nuclear export. Even when endogenously expressed, Nis1 accumulates in the nucleus when Nba1 is absent. When either Aim44 or Nis1 are overexpressed, Nba1 is displaced from the bud neck, further consistent with the mutual interactions of these proteins. Collectively, our results indicate that a previously unappreciated level at which localization of septin‐associated proteins is controlled is via regulation of their nucleocytoplasmic shuttling, which places constraints on their availability for complex formation with other partners at the bud neck.
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Affiliation(s)
- Adam M Perez
- Division of Biochemistry, Biophysics and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, California
| | - Jeremy Thorner
- Division of Biochemistry, Biophysics and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, California
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24
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Hapak SM, Rothlin CV, Ghosh S. PAR3-PAR6-atypical PKC polarity complex proteins in neuronal polarization. Cell Mol Life Sci 2018; 75:2735-2761. [PMID: 29696344 PMCID: PMC11105418 DOI: 10.1007/s00018-018-2828-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 04/03/2018] [Accepted: 04/23/2018] [Indexed: 01/01/2023]
Abstract
Polarity is a fundamental feature of cells. Protein complexes, including the PAR3-PAR6-aPKC complex, have conserved roles in establishing polarity across a number of eukaryotic cell types. In neurons, polarity is evident as distinct axonal versus dendritic domains. The PAR3, PAR6, and aPKC proteins also play important roles in neuronal polarization. During this process, either aPKC kinase activity, the assembly of the PAR3-PAR6-aPKC complex or the localization of these proteins is regulated downstream of a number of signaling pathways. In turn, the PAR3, PAR6, and aPKC proteins control various effector molecules to establish neuronal polarity. Herein, we discuss the many signaling mechanisms and effector functions that have been linked to PAR3, PAR6, and aPKC during the establishment of neuronal polarity.
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Affiliation(s)
- Sophie M Hapak
- Department of Medicine, School of Medicine, University of Minnesota, 401 East River Parkway, Minneapolis, MN, 55455, USA.
| | - Carla V Rothlin
- Department of Immunobiology, School of Medicine, Yale University, 300 Cedar Street, New Haven, CT, 06520, USA
- Department of Pharmacology, School of Medicine, Yale University, 333 Cedar Street, New Haven, CT, 06520, USA
| | - Sourav Ghosh
- Department of Neurology, School of Medicine, Yale University, 300 George Street, New Haven, CT, 06511, USA
- Department of Pharmacology, School of Medicine, Yale University, 333 Cedar Street, New Haven, CT, 06520, USA
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25
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Miller KE, Lo WC, Lee ME, Kang PJ, Park HO. Fine-tuning the orientation of the polarity axis by Rga1, a Cdc42 GTPase-activating protein. Mol Biol Cell 2017; 28:3773-3788. [PMID: 29074565 PMCID: PMC5739294 DOI: 10.1091/mbc.e17-01-0074] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 10/19/2017] [Accepted: 10/20/2017] [Indexed: 01/29/2023] Open
Abstract
In vivo and in vitro analyses reveal how a Cdc42 GTPase-activating protein (GAP) interacts with other negative polarity cues at old division sites in budding yeast. Mathematical modeling suggests that spatial distribution of a Cdc42 GAP in coordination with G1 progression is critical for fine-tuning the orientation of the polarity axis. In yeast and animal cells, signaling pathways involving small guanosine triphosphatases (GTPases) regulate cell polarization. In budding yeast, selection of a bud site directs polarity establishment and subsequently determines the plane of cell division. Rga1, a Cdc42 GTPase-activating protein, prevents budding within the division site by inhibiting Cdc42 repolarization. A protein complex including Nba1 and Nis1 is involved in preventing rebudding at old division sites, yet how these proteins and Rga1 might function in negative polarity signaling has been elusive. Here we show that Rga1 transiently localizes to the immediately preceding and older division sites by interacting with Nba1 and Nis1. The LIM domains of Rga1 are necessary for its interaction with Nba1, and loss of this interaction results in premature delocalization of Rga1 from the immediately preceding division site and, consequently, abnormal bud-site selection in daughter cells. However, such defects are minor in mother cells of these mutants, likely because the G1 phase is shorter and a new bud site is established prior to delocalization of Rga1. Indeed, our biphasic mathematical model of Cdc42 polarization predicts that premature delocalization of Rga1 leads to more frequent Cdc42 repolarization within the division site when the first temporal step in G1 is assumed to last longer. Spatial distribution of a Cdc42 GAP in coordination with G1 progression may thus be critical for fine-tuning the orientation of the polarity axis in yeast.
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Affiliation(s)
| | - Wing-Cheong Lo
- Department of Mathematics, City University of Hong Kong, Kowloon, Hong Kong
| | - Mid Eum Lee
- Molecular Cellular Developmental Biology Program and
| | - Pil Jung Kang
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210
| | - Hay-Oak Park
- Molecular Cellular Developmental Biology Program and .,Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210
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26
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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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27
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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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28
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Meitinger F, Pereira G. The septin-associated kinase Gin4 recruits Gps1 to the site of cell division. Mol Biol Cell 2017; 28:883-889. [PMID: 28148650 PMCID: PMC5385937 DOI: 10.1091/mbc.e16-09-0687] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Revised: 01/23/2017] [Accepted: 01/24/2017] [Indexed: 01/24/2023] Open
Abstract
Gps1 is a regulator of Rho GTPases during cell division. Cell cycle–regulated recruitment of Gps1 to the cell division site is under control of the conserved kinase Gin4 and the bud neck–associated protein Nba1. This biphasic recruitment is required for the spatiotemporal activation of Rho1 and inhibition of Cdc42. Cell cycle–dependent morphogenesis of unicellular organisms depends on the spatiotemporal control of cell polarity. Rho GTPases are the major players that guide cells through structural reorganizations such as cytokinesis (Rho1 dependent) and polarity establishment (Cdc42 dependent). In budding yeast, the protein Gps1 plays a pivotal role in both processes. Gps1 resides at the bud neck to maintain Rho1 localization and restrict Cdc42 activity during cytokinesis. Here we analyze how Gps1 is recruited to the bud neck during the cell cycle. We show that different regions of Gps1 and the septin-associated kinase Gin4 are involved in maintaining Gps1 at the bud neck from late G1 phase until midanaphase. From midanaphase, the targeting function of Gin4 is taken over by the bud neck–associated protein Nba1. Our data show that Gps1 is targeted to the cell division site in a biphasic manner, via Gin4 and Nba1, to control the spatiotemporal activation of Rho1 and inhibition of Cdc42.
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Affiliation(s)
- Franz Meitinger
- Centre for Organismal Studies and German Cancer Research Center, DKFZ-ZMBH Alliance, and Molecular Biology of Centrosomes and Cilia Unit, University of Heidelberg, 69120 Heidelberg, Germany
| | - Gislene Pereira
- Centre for Organismal Studies and German Cancer Research Center, DKFZ-ZMBH Alliance, and Molecular Biology of Centrosomes and Cilia Unit, University of Heidelberg, 69120 Heidelberg, Germany
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29
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Chen KL, Crane MM, Kaeberlein M. Microfluidic technologies for yeast replicative lifespan studies. Mech Ageing Dev 2017; 161:262-269. [PMID: 27015709 PMCID: PMC5035173 DOI: 10.1016/j.mad.2016.03.009] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Revised: 03/18/2016] [Accepted: 03/21/2016] [Indexed: 01/02/2023]
Abstract
The budding yeast Saccharomyces cerevisiae has been used as a model organism for the study of aging for over 50 years. In this time, the canonical aging experiment-replicative lifespan analysis by manual microdissection-has remained essentially unchanged. Recently, microfluidic technologies have been developed that may be able to substitute for this time- and labor-intensive procedure. These technologies also allow cell physiology to be observed throughout the entire lifetime. Here, we review these devices, novel observations they have made possible, and some of the current system limitations.
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Affiliation(s)
- Kenneth L Chen
- Department of Pathology, University of Washington, Seattle, WA, USA; Department of Genome Sciences, University of Washington, Seattle, WA, USA; Medical Scientist Training Program, University of Washington, Seattle, WA, USA
| | - Matthew M Crane
- Department of Pathology, University of Washington, Seattle, WA, USA
| | - Matt Kaeberlein
- Department of Pathology, University of Washington, Seattle, WA, USA.
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30
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Abstract
Cytokinesis is the final process in the cell cycle that physically divides one cell into two. In budding yeast, cytokinesis is driven by a contractile actomyosin ring (AMR) and the simultaneous formation of a primary septum, which serves as template for cell wall deposition. AMR assembly, constriction, primary septum formation and cell wall deposition are successive processes and tightly coupled to cell cycle progression to ensure the correct distribution of genetic material and cell organelles among the two rising cells prior to cell division. The role of the AMR in cytokinesis and the molecular mechanisms that drive AMR constriction and septation are the focus of current research. This review summarizes the recent progresses in our understanding of how budding yeast cells orchestrate the multitude of molecular mechanisms that control AMR driven cytokinesis in a spatio-temporal manner to achieve an error free cell division.
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31
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Meitinger F, Pereira G. Visualization of Cytokinesis Events in Budding Yeast by Transmission Electron Microscopy. Methods Mol Biol 2016; 1369:87-95. [PMID: 26519307 DOI: 10.1007/978-1-4939-3145-3_7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
In yeast cells, cytokinesis is accompanied by morphological changes due to cell wall growth during furrow ingression and abscission. The characteristics of the growing cell wall can be used as an indicator for the function of the contractile actomyosin ring, the Rho-GTPases Rho1 and Cdc42 and/or other factors that drive cytokinesis. The ultrastructural information of the cell wall can be easily acquired by transmission electron microscopy, which makes this technique an invaluable tool to analyze cell division in yeast cells. Here, we describe the process of embedding and staining budding yeast cells for transmission electron microscopic analysis of cytokinetic events.
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Affiliation(s)
- Franz Meitinger
- DKFZ-ZMBH Alliance, German Cancer Research Center (DKFZ), University of Heidelberg, Im Neuenheimer Feld 581, 69120, Heidelberg, Germany.,Ludwig Institute for Cancer Research, 9500 Gilman Drive, CMM East, La Jolla, CA, 92093, USA
| | - Gislene Pereira
- DKFZ-ZMBH Alliance, German Cancer Research Center (DKFZ), University of Heidelberg, Im Neuenheimer Feld 581, 69120, Heidelberg, Germany.
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32
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Jo MC, Liu W, Gu L, Dang W, Qin L. High-throughput analysis of yeast replicative aging using a microfluidic system. Proc Natl Acad Sci U S A 2015; 112:9364-9. [PMID: 26170317 PMCID: PMC4522780 DOI: 10.1073/pnas.1510328112] [Citation(s) in RCA: 113] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Saccharomyces cerevisiae has been an important model for studying the molecular mechanisms of aging in eukaryotic cells. However, the laborious and low-throughput methods of current yeast replicative lifespan assays limit their usefulness as a broad genetic screening platform for research on aging. We address this limitation by developing an efficient, high-throughput microfluidic single-cell analysis chip in combination with high-resolution time-lapse microscopy. This innovative design enables, to our knowledge for the first time, the determination of the yeast replicative lifespan in a high-throughput manner. Morphological and phenotypical changes during aging can also be monitored automatically with a much higher throughput than previous microfluidic designs. We demonstrate highly efficient trapping and retention of mother cells, determination of the replicative lifespan, and tracking of yeast cells throughout their entire lifespan. Using the high-resolution and large-scale data generated from the high-throughput yeast aging analysis (HYAA) chips, we investigated particular longevity-related changes in cell morphology and characteristics, including critical cell size, terminal morphology, and protein subcellular localization. In addition, because of the significantly improved retention rate of yeast mother cell, the HYAA-Chip was capable of demonstrating replicative lifespan extension by calorie restriction.
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Affiliation(s)
- Myeong Chan Jo
- Department of Nanomedicine, Houston Methodist Research Institute, Houston, TX 77030; Department of Cell and Developmental Biology, Weill Cornell Medical College, New York, NY 10065
| | - Wei Liu
- Huffington Center on Aging, Baylor College of Medicine, Houston, TX 77030
| | - Liang Gu
- Department of Nanomedicine, Houston Methodist Research Institute, Houston, TX 77030
| | - Weiwei Dang
- Huffington Center on Aging, Baylor College of Medicine, Houston, TX 77030
| | - Lidong Qin
- Department of Nanomedicine, Houston Methodist Research Institute, Houston, TX 77030; Department of Cell and Developmental Biology, Weill Cornell Medical College, New York, NY 10065;
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33
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The Carboxy-Terminal Tails of Septins Cdc11 and Shs1 Recruit Myosin-II Binding Factor Bni5 to the Bud Neck in Saccharomyces cerevisiae. Genetics 2015; 200:843-62. [PMID: 25971666 DOI: 10.1534/genetics.115.176503] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Accepted: 05/08/2015] [Indexed: 12/20/2022] Open
Abstract
UNLABELLED Septins are a conserved family of GTP-binding proteins that form heterooctameric complexes that assemble into higher-order structures. In yeast, septin superstructure at the bud neck serves as a barrier to separate a daughter cell from its mother and as a scaffold to recruit the proteins that execute cytokinesis. However, how septins recruit specific factors has not been well characterized. In the accompanying article in this issue, (Finnigan et al. 2015), we demonstrated that the C-terminal extensions (CTEs) of the alternative terminal subunits of septin heterooctamers, Cdc11 and Shs1, share a role required for optimal septin function in vivo. Here we describe our use of unbiased genetic approaches (both selection of dosage suppressors and analysis of synthetic interactions) that pinpointed Bni5 as a protein that interacts with the CTEs of Cdc11 and Shs1. Furthermore, we used three independent methods-construction of chimeric proteins, noncovalent tethering mediated by a GFP-targeted nanobody, and imaging by fluorescence microscopy-to confirm that a physiologically important function of the CTEs of Cdc11 and Shs1 is optimizing recruitment of Bni5 and thereby ensuring efficient localization at the bud neck of Myo1, the type II myosin of the actomyosin contractile ring.Related article in GENETICS Finnigan, G. C. et al., 2015 Comprehensive Genetic Analysis of Paralogous Terminal Septin Subunits Shs1 and Cdc11 in Saccharomyces cerevisiae. Genetics 200: 841-861.
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34
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Frey O, Rudolf F, Schmidt GW, Hierlemann A. Versatile, simple-to-use microfluidic cell-culturing chip for long-term, high-resolution, time-lapse imaging. Anal Chem 2015; 87:4144-51. [PMID: 25837982 PMCID: PMC7610638 DOI: 10.1021/ac504611t] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Optical long-term observation of individual cells, combined with modern data analysis tools, allows for a detailed study of cell-to-cell variability, heredity, and differentiation. We developed a microfluidic device featuring facile cell loading, simple and robust operation, and which is amenable to high-resolution life-cell imaging. Different cell strains can be grown in parallel in the device under constant or changing media perfusion without cross-talk between the cell ensembles. The culturing chamber has been optimized for use with nonadherent cells, such as Saccharomyces cerevisiae, and enables controlled colony growth over multiple generations under aerobic or anaerobic conditions. Small changes in the layout will make the device also useable with bacteria or mammalian cells. The platform can be readily set up in every laboratory with minimal additional requirements and can be operated without technology training.
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Affiliation(s)
- Olivier Frey
- ETH Zürich, Department of Biosystems Science and Engineering, Bio Engineering Laboratory, Mattenstrasse 26, 4058 Basel, Switzerland
| | - Fabian Rudolf
- ETH Zürich, Department of Biosystems Science and Engineering, Computational Systems Biology Group, Mattenstrasse 26, 4058 Basel, Switzerland
| | - Gregor W. Schmidt
- ETH Zürich, Department of Biosystems Science and Engineering, Bio Engineering Laboratory, Mattenstrasse 26, 4058 Basel, Switzerland
| | - Andreas Hierlemann
- ETH Zürich, Department of Biosystems Science and Engineering, Bio Engineering Laboratory, Mattenstrasse 26, 4058 Basel, Switzerland
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35
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Abstract
Cell polarity establishment has been studied in great detail, but much less is known about mechanisms that prevent polarization. Reporting recently in Cell, Meitinger et al. (2014) identify an elaborate mechanism in yeast cells that efficiently inhibits Cdc42 activation in cytokinesis remnants. Failure of this "anti-polarization" memory increases replicative aging.
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Affiliation(s)
- Roland Wedlich-Söldner
- Institute of Cell Dynamics and Imaging and Cells-in-Motion Cluster of Excellence (EXC 1003 - CiM), University of Muenster, Von Esmarchstrasse 56, 48149 Muenster, Germany.
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