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Ragon M, Bertheau L, Dumont J, Bellanger T, Grosselin M, Basu M, Pourcelot E, Horrigue W, Denimal E, Marin A, Vaucher B, Berland A, Lepoivre C, Dupont S, Beney L, Davey H, Guyot S. The Yin-Yang of the Green Fluorescent Protein: Impact on Saccharomyces cerevisiae stress resistance. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2023; 238:112603. [PMID: 36459911 DOI: 10.1016/j.jphotobiol.2022.112603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Revised: 11/09/2022] [Accepted: 11/21/2022] [Indexed: 11/27/2022]
Abstract
Although fluorescent proteins are widely used as biomarkers (Yin), no study focuses on their influence on the microbial stress response. Here, the Green Fluorescent Protein (GFP) was fused to two proteins of interest in Saccharomyces cerevisiae. Pab1p and Sur7p, respectively involved in stress granules structure and in Can1 membrane domains. These were chosen since questions remain regarding the understanding of the behavior of S. cerevisiae facing different heat kinetics or oxidative stresses. The main results showed that Pab1p-GFP fluorescent mutant displayed a higher resistance than that of the wild type under a heat shock. Moreover, fluorescent mutants exposed to oxidative stresses displayed changes in the cultivability compared to the wild type strain. In silico approaches showed that the presence of the GFP did not influence the structure and so the functionality of the tagged proteins meaning that changes in yeast resistance were certainly related to GFP ROS-scavenging ability (Yang).
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Affiliation(s)
- Mélanie Ragon
- Univ. Bourgogne Franche-Comté, Institut Agro, PAM UMR A 02.102, F-21000 Dijon, France
| | - Lucie Bertheau
- Univ. Bourgogne Franche-Comté, Institut Agro, PAM UMR A 02.102, F-21000 Dijon, France
| | - Jennifer Dumont
- Univ. Bourgogne Franche-Comté, Institut Agro, PAM UMR A 02.102, F-21000 Dijon, France
| | - Tiffany Bellanger
- Univ. Bourgogne Franche-Comté, Institut Agro, PAM UMR A 02.102, F-21000 Dijon, France
| | - Marie Grosselin
- Univ. Bourgogne Franche-Comté, Institut Agro, PAM UMR A 02.102, F-21000 Dijon, France
| | - Mohini Basu
- Univ. Bourgogne Franche-Comté, Institut Agro, PAM UMR A 02.102, F-21000 Dijon, France
| | - Eléonore Pourcelot
- Univ. Bourgogne Franche-Comté, Institut Agro, PAM UMR A 02.102, F-21000 Dijon, France
| | - Walid Horrigue
- UMR Agroécologie Équipe Biocom, INRAE Dijon, Institut Agro, 26 Bd Dr Petitjean, 21000 Dijon, France
| | - Emmanuel Denimal
- Institut Agro Dijon, Direction Scientifique, Appui à la Recherche, 26 Bd Dr Petitjean, 21000 Dijon, France
| | - Ambroise Marin
- Plateau Technique d'IMagerie Spectroscopique (PIMS), DImaCell Platform Université de Bourgogne - INRAE, Dijon, France
| | - Basile Vaucher
- Univ. Bourgogne Franche-Comté, Institut Agro, PAM UMR A 02.102, F-21000 Dijon, France
| | - Antoine Berland
- Univ. Bourgogne Franche-Comté, Institut Agro, PAM UMR A 02.102, F-21000 Dijon, France
| | - Corentin Lepoivre
- Univ. Bourgogne Franche-Comté, Institut Agro, PAM UMR A 02.102, F-21000 Dijon, France
| | - Sébastien Dupont
- Univ. Bourgogne Franche-Comté, Institut Agro, PAM UMR A 02.102, F-21000 Dijon, France
| | - Laurent Beney
- Univ. Bourgogne Franche-Comté, Institut Agro, PAM UMR A 02.102, F-21000 Dijon, France
| | - Hazel Davey
- Department of Life Sciences, Aberystwyth University, Aberystwyth, United Kingdom
| | - Stéphane Guyot
- Univ. Bourgogne Franche-Comté, Institut Agro, PAM UMR A 02.102, F-21000 Dijon, France.
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2
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Feng MW, Delneri D, Millar CB, O'Keefe RT. Eisosome disruption by noncoding RNA deletion increases protein secretion in yeast. PNAS NEXUS 2022; 1:pgac241. [PMID: 36712349 PMCID: PMC9802208 DOI: 10.1093/pnasnexus/pgac241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 10/24/2022] [Indexed: 11/07/2022]
Abstract
Noncoding RNAs (ncRNAs) regulate many aspects of gene expression. We investigated how ncRNAs affected protein secretion in yeast by large-scale screening for improved endogenous invertase secretion in ncRNA deletion strains with deletion of stable unannotated transcripts (SUTs), cryptic unstable transcripts (CUTs), tRNAs, or snRNAs. We identified three candidate ncRNAs, SUT418, SUT390, and SUT125, that improved endogenous invertase secretion when deleted. As SUTs can affect expression of nearby genes, we quantified adjacent gene transcription and found that the PIL1 gene was down-regulated in the SUT125 deletion strain. Pil1 is a core component of eisosomes, nonmobile invaginations found throughout the plasma membrane. PIL1 knockout alone, or in combination with eisosome components LSP1 or SUR7, resulted in further increased secretion of invertase. Secretion of heterologous GFP was also increased upon PIL1 deletion, but this increase was signal sequence dependent. To reveal the potential for increased biopharmaceutical production, secretion of monoclonal antibody Pexelizumab scFv peptide was increased by PIL1 deletion. Global analysis of secreted proteins revealed that approximately 20% of secreted proteins, especially serine-enriched secreted proteins, including invertase, were increased upon eisosome disruption. Eisosomes are enriched with APC transporters and sphingolipids, which are essential components for secretory vesicle formation and protein sorting. Sphingolipid and serine biosynthesis pathways were up-regulated upon PIL1 deletion. We propose that increased secretion of endogenous and heterologous proteins upon PIL1 deletion resulted from sphingolipid redistribution in the plasma membrane and up-regulated sphingolipid biosynthesis. Overall, a new pathway to improve protein secretion in yeast via eisosome disruption has been identified.
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Affiliation(s)
- Matthew Wenjie Feng
- Division of Evolution, Infection and Genomics, Faculty of Biology, Medicine and Health, The University of Manchester, Oxford Road, Manchester M13 9PT, UK
| | - Daniela Delneri
- Division of Evolution, Infection and Genomics, Faculty of Biology, Medicine and Health, The University of Manchester, Oxford Road, Manchester M13 9PT, UK,Manchester Institute of Biotechnology, Faculty of Biology Medicine and Health, The University of Manchester, 131 Princess street, Manchester, M1 7DN, UK
| | - Catherine B Millar
- Division of Evolution, Infection and Genomics, Faculty of Biology, Medicine and Health, The University of Manchester, Oxford Road, Manchester M13 9PT, UK
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3
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Zhang LB, Qiu TT, Huang ZH, Ye XY, Guan Y. Transcriptomic analysis of Sur7-mediated response of Beauveria bassiana to different nutritional conditions. FEMS Microbiol Lett 2021; 368:6123717. [PMID: 33512422 DOI: 10.1093/femsle/fnab003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Accepted: 01/27/2021] [Indexed: 01/09/2023] Open
Abstract
Integrity of the cell wall is requisite for fungal growth and function. Sur7 governs cell wall composition, and affects conidial sporulation and germination in Beauveria bassiana, a filamentous entomopathogenic fungus. The role of Sur7 in fungal growth on various nutrients remains unclear. We have previously reported that Sur7 deletion results in the attenuation of B. bassiana growth on supplemented Sabouraud dextrose agar (SDAY) and minimal Czapek-Dox agar (CDA) compared to wild type (WT). Here, we used transcriptomic analysis to compare WT and Sur7 mutant (ΔSur7) responses to CDA and SDAY. Growth on CDA, compared with that on SDAY, affected the expression of more genes in the WT than in the mutant. Differentially expressed genes were enriched for transportation process terms in the ΔSur7 mutant and metabolic process terms in the WT. Different processes were repressed in the ΔSur7 (metabolic process) and WT (ribosome synthesis) cells. Despite the shared enrichment of nitrogen metabolism genes, differentially expressed genes were enriched in distinct saccharide-energy metabolism terms in each strain. We conclude that Sur7 ensures the growth of B. bassiana in a minimal medium by influencing the expression of genes involved in the consumption of sucrose via specific energy metabolism pathways.
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Affiliation(s)
- Long-Bin Zhang
- Fujian Key Laboratory of Marine Enzyme Engineering, College of Biological Science and Engineering, Fuzhou University, Fuzhou, Fujian, 350116, China
| | - Ting-Ting Qiu
- Fujian Key Laboratory of Marine Enzyme Engineering, College of Biological Science and Engineering, Fuzhou University, Fuzhou, Fujian, 350116, China
| | - Zhi-Hong Huang
- Chemical Engineering Istitute, Huaqiao University, Xiamen, Fujian, 361021, China
| | - Xiu-Yun Ye
- Fujian Key Laboratory of Marine Enzyme Engineering, College of Biological Science and Engineering, Fuzhou University, Fuzhou, Fujian, 350116, China
| | - Yi Guan
- Fujian Key Laboratory of Marine Enzyme Engineering, College of Biological Science and Engineering, Fuzhou University, Fuzhou, Fujian, 350116, China
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4
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Wang R, Zhao P, Ge X, Tian P. Overview of Alternaria alternata Membrane Proteins. Indian J Microbiol 2020; 60:269-282. [PMID: 32647391 DOI: 10.1007/s12088-020-00873-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Accepted: 04/11/2020] [Indexed: 11/29/2022] Open
Abstract
Alternaria species are mainly saprophytic fungi, but some pathotypes of Alternaria alternata infect economically important plants including cereal crops, vegetables and fruits. Specially, A. alternata generates toxins which contaminate food and feed. To date, management of A. alternata relies primarily on fungicides. However, the control efficacy in most cases is below expectation due to ubiquity of A. alternata and resistance to fungicides. To mitigate resistance and develop long-lasting fungicides, uncovering multiple rather than single target is a prerequisite. Membrane proteins are potential targets of fungicides owing to wide participation in myriad biochemical events especially material transport, signal transduction and pathogenicity. However, so far, little is known about the distribution and molecular structure of A. alternata membrane proteins (AAMPs). Herein we summarize AAMPs by data mining and subsequent structure prediction. We also outline the state-of-the-art research advances of AAMPs especially those closely related to pathogenicity. Overall, this review aims to portray a picture of AAMPs and provide valuable insights for future development of highly efficient fungicides towards A. alternata or beyond.
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Affiliation(s)
- Ruyi Wang
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, 100029 People's Republic of China
| | - Peng Zhao
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, 100029 People's Republic of China
| | - Xizhen Ge
- College of Biochemical Engineering, Beijing Union University, Beijing, 100023 People's Republic of China
| | - Pingfang Tian
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, 100029 People's Republic of China
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5
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Zhang LB, Tang L, Guan Y, Feng MG. Subcellular localization of Sur7 and its pleiotropic effect on cell wall integrity, multiple stress responses, and virulence of Beauveria bassiana. Appl Microbiol Biotechnol 2020; 104:6669-6678. [DOI: 10.1007/s00253-020-10736-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 05/28/2020] [Accepted: 06/07/2020] [Indexed: 10/24/2022]
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6
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Yu SC, Kuemmel F, Skoufou-Papoutsaki MN, Spanu PD. Yeast transformation efficiency is enhanced by TORC1- and eisosome-dependent signaling. Microbiologyopen 2018; 8:e00730. [PMID: 30311441 PMCID: PMC6528558 DOI: 10.1002/mbo3.730] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Revised: 08/09/2018] [Accepted: 08/10/2018] [Indexed: 12/12/2022] Open
Abstract
Transformation of baker's yeast (Saccharomyces cerevisiae) plays a key role in several experimental techniques, yet the molecular mechanisms underpinning transformation are still unclear. The addition of amino acids to the growth and transformation medium increases transformation efficiency. Here, we show that target of rapamycin complex 1 (TORC1) activated by amino acids enhances transformation via ubiquitin‐mediated endocytosis. We created mutants of the TORC1 pathway, alpha‐arrestins, and eisosome‐related genes. Our results demonstrate that the TORC1‐Npr1‐Art1/Rsp5 pathway regulates yeast transformation. Based on our previous study, activation of this pathway results in up to a 200‐fold increase in transformation efficiency, or greater. Additionally, we suggest DNA may be taken up by domains at the membrane compartment of Can1 (MCC) in the plasma membrane formed by eisosomes. Yeast studies on transformation could be used as a platform to understand the mechanism of DNA uptake in mammalian systems, which is clinically relevant to optimize gene therapy.
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Affiliation(s)
- Sheng-Chun Yu
- Department of Life Sciences, Imperial College London, London, UK
| | - Florian Kuemmel
- Department of Life Sciences, Imperial College London, London, UK
| | | | - Pietro D Spanu
- Department of Life Sciences, Imperial College London, London, UK
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7
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MCC/Eisosomes Regulate Cell Wall Synthesis and Stress Responses in Fungi. J Fungi (Basel) 2017; 3:jof3040061. [PMID: 29371577 PMCID: PMC5753163 DOI: 10.3390/jof3040061] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 10/26/2017] [Accepted: 10/31/2017] [Indexed: 12/20/2022] Open
Abstract
The fungal plasma membrane is critical for cell wall synthesis and other important processes including nutrient uptake, secretion, endocytosis, morphogenesis, and response to stress. To coordinate these diverse functions, the plasma membrane is organized into specialized compartments that vary in size, stability, and composition. One recently identified domain known as the Membrane Compartment of Can1 (MCC)/eisosome is distinctive in that it corresponds to a furrow-like invagination in the plasma membrane. MCC/eisosomes have been shown to be formed by the Bin/Amphiphysin/Rvs (BAR) domain proteins Lsp1 and Pil1 in a range of fungi. MCC/eisosome domains influence multiple cellular functions; but a very pronounced defect in cell wall synthesis has been observed for mutants with defects in MCC/eisosomes in some yeast species. For example, Candida albicans MCC/eisosome mutants display abnormal spatial regulation of cell wall synthesis, including large invaginations and altered chemical composition of the walls. Recent studies indicate that MCC/eisosomes affect cell wall synthesis in part by regulating the levels of the key regulatory lipid phosphatidylinositol 4,5-bisphosphate (PI4,5P2) in the plasma membrane. One general way MCC/eisosomes function is by acting as protected islands in the plasma membrane, since these domains are very stable. They also act as scaffolds to recruit >20 proteins. Genetic studies aimed at defining the function of the MCC/eisosome proteins have identified important roles in resistance to stress, such as resistance to oxidative stress mediated by the flavodoxin-like proteins Pst1, Pst2, Pst3 and Ycp4. Thus, MCC/eisosomes play multiple roles in plasma membrane organization that protect fungal cells from the environment.
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8
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Dewhurst-Maridor G, Abegg D, David FPA, Rougemont J, Scott CC, Adibekian A, Riezman H. The SAGA complex, together with transcription factors and the endocytic protein Rvs167p, coordinates the reprofiling of gene expression in response to changes in sterol composition in Saccharomyces cerevisiae. Mol Biol Cell 2017; 28:2637-2649. [PMID: 28768829 PMCID: PMC5620372 DOI: 10.1091/mbc.e17-03-0169] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 07/21/2017] [Accepted: 07/28/2017] [Indexed: 01/26/2023] Open
Abstract
The SAGA complex, together with transcription factors and Rvs167p, coordinates sterol-dependent transcription changes. In ergosterol mutants the SAGA complex increases its occupancy on ergosterol biosynthesis and anaerobic gene promoters, recruits the SWI/SNF complex, and binds to transcription factors and Rvs167p. Genes encoding stress proteins and basic amino acid synthesis are also affected even though promoter occupancy is not changed. Changes in cellular sterol species and concentrations can have profound effects on the transcriptional profile. In yeast, mutants defective in sterol biosynthesis show a wide range of changes in transcription, including a coinduction of anaerobic genes and ergosterol biosynthesis genes, biosynthesis of basic amino acids, and several stress genes. However the mechanisms underlying these changes are unknown. We identified mutations in the SAGA complex, a coactivator of transcription, which abrogate the ability to carry out most of these sterol-dependent transcriptional changes. In the erg3 mutant, the SAGA complex increases its occupancy time on many of the induced ergosterol and anaerobic gene promoters, increases its association with several relevant transcription factors and the SWI/SNF chromatin remodeling complex, and surprisingly, associates with an endocytic protein, Rvs167p, suggesting a moonlighting function for this protein in the sterol-regulated induction of the heat shock protein, HSP42 and HSP102, mRNAs.
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Affiliation(s)
| | - Daniel Abegg
- Department of Organic Chemistry, University of Geneva, 1205 Geneva, Switzerland.,NCCR Chemical Biology, University of Geneva, 1205 Geneva, Switzerland
| | - Fabrice P A David
- Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Jacques Rougemont
- Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Cameron C Scott
- Department of Biochemistry, University of Geneva, 1205 Geneva, Switzerland.,Department of Biochemistry, University of Geneva, 1205 Geneva, Switzerland
| | - Alexander Adibekian
- Department of Organic Chemistry, University of Geneva, 1205 Geneva, Switzerland.,NCCR Chemical Biology, University of Geneva, 1205 Geneva, Switzerland
| | - Howard Riezman
- Department of Biochemistry, University of Geneva, 1205 Geneva, Switzerland .,NCCR Chemical Biology, University of Geneva, 1205 Geneva, Switzerland
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9
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Plasma Membrane Proteolipid 3 Protein Modulates Amphotericin B Resistance through Sphingolipid Biosynthetic Pathway. Sci Rep 2015; 5:9685. [PMID: 25965669 PMCID: PMC4428271 DOI: 10.1038/srep09685] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Accepted: 03/16/2015] [Indexed: 02/08/2023] Open
Abstract
Invasive opportunistic fungal infections of humans are common among those suffering from impaired immunity, and are difficult to treat resulting in high mortality. Amphotericin B (AmB) is one of the few antifungals available to treat such infections. The AmB resistance mechanisms reported so far mainly involve decrease in ergosterol content or alterations in cell wall. In contrast, depletion of sphingolipids sensitizes cells to AmB. Recently, overexpression of PMP3 gene, encoding plasma membrane proteolipid 3 protein, was shown to increase and its deletion to decrease, AmB resistance. Here we have explored the mechanistic basis of PMP3 effect on AmB resistance. It was found that ergosterol content and cell wall integrity are not related to modulation of AmB resistance by PMP3. A few prominent phenotypes of PMP3 delete strain, namely, defective actin polarity, impaired salt tolerance, and reduced rate of endocytosis are also not related to its AmB-sensitivity. However, PMP3 overexpression mediated increase in AmB resistance requires a functional sphingolipid pathway. Moreover, AmB sensitivity of strains deleted in PMP3 can be suppressed by the addition of phytosphingosine, a sphingolipid pathway intermediate, confirming the importance of this pathway in modulation of AmB resistance by PMP3.
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10
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Abstract
Endocytosis, the process whereby the plasma membrane invaginates to form vesicles, is essential for bringing many substances into the cell and for membrane turnover. The mechanism driving clathrin-mediated endocytosis (CME) involves > 50 different protein components assembling at a single location on the plasma membrane in a temporally ordered and hierarchal pathway. These proteins perform precisely choreographed steps that promote receptor recognition and clustering, membrane remodeling, and force-generating actin-filament assembly and turnover to drive membrane invagination and vesicle scission. Many critical aspects of the CME mechanism are conserved from yeast to mammals and were first elucidated in yeast, demonstrating that it is a powerful system for studying endocytosis. In this review, we describe our current mechanistic understanding of each step in the process of yeast CME, and the essential roles played by actin polymerization at these sites, while providing a historical perspective of how the landscape has changed since the preceding version of the YeastBook was published 17 years ago (1997). Finally, we discuss the key unresolved issues and where future studies might be headed.
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Affiliation(s)
- Bruce L Goode
- Brandeis University, Department of Biology, Rosenstiel Center, Waltham, Massachusetts 02454
| | - Julian A Eskin
- Brandeis University, Department of Biology, Rosenstiel Center, Waltham, Massachusetts 02454
| | - Beverly Wendland
- The Johns Hopkins University, Department of Biology, Baltimore, Maryland 21218
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11
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Affiliation(s)
- Lois M. Douglas
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, New York 11794; ,
| | - James B. Konopka
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, New York 11794; ,
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12
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Membrane Compartment Occupied by Can1 (MCC) and Eisosome Subdomains of the Fungal Plasma Membrane. MEMBRANES 2014; 1:394-411. [PMID: 22368779 PMCID: PMC3285718 DOI: 10.3390/membranes1040394] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Studies on the budding yeast Saccharomyces cerevisiae have revealed that fungal plasma membranes are organized into different subdomains. One new domain termed MCC/eisosomes consists of stable punctate patches that are distinct from lipid rafts. The MCC/eisosome domains correspond to furrows in the plasma membrane that are about 300 nm long and 50 nm deep. The MCC portion includes integral membrane proteins, such as the tetraspanners Sur7 and Nce102. The adjacent eisosome includes proteins that are peripherally associated with the membrane, including the BAR domains proteins Pil1 and Lsp1 that are thought to promote membrane curvature. Genetic analysis of the MCC/eisosome components indicates these domains broadly affect overall plasma membrane organization. The mechanisms regulating the formation of MCC/eisosomes in model organisms will be reviewed as well as the role of these plasma membrane domains in fungal pathogenesis and response to antifungal drugs.
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13
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Olivera-Couto A, Aguilar PS. Eisosomes and plasma membrane organization. Mol Genet Genomics 2012; 287:607-20. [DOI: 10.1007/s00438-012-0706-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Accepted: 06/29/2012] [Indexed: 12/16/2022]
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14
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Alvarez FJ, Douglas LM, Konopka JB. The Sur7 protein resides in punctate membrane subdomains and mediates spatial regulation of cell wall synthesis in Candida albicans. Commun Integr Biol 2011; 2:76-7. [PMID: 19704893 DOI: 10.4161/cib.7478] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2008] [Accepted: 11/22/2008] [Indexed: 11/19/2022] Open
Abstract
The eukaryotic plasma membrane is organized into distinct domains that contribute to its function. One new type of plasma membrane domain was identified by studies on the Sur7 protein, which was discovered in the yeast S. cerevisiae to localize into stable punctate patches known as MCC or eisosomes. Sur7 shares similarities with Claudin proteins that form tight junction domains in animal cells, suggesting common roles for these tetraspanning membrane proteins. Recent analysis of C. albicans revealed broad new roles for Sur7; a sur7Delta mutant mislocalized septins and actin and was defective in morphogenesis. Strikingly, cell wall synthesis was very abnormal, including long projections of chitin-rich cell wall into the cytoplasm. Some phenotypes of the sur7Delta mutant are similar to the effects of inhibiting cell wall beta-glucan synthesis. This suggests that the abnormal cell wall structures are related to the increased chitin synthesis commonly seen under cell wall stress conditions, which could be mediated in part by the altered septin localization. Altogether, these results identify new roles for Sur7 and MCC/eisosomes in plasma membrane organization and coordination of the different aspects of cell wall synthesis.
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Affiliation(s)
- Francisco J Alvarez
- Department of Molecular Genetics and Microbiology; Stony Brook University; Stony Brook, NY USA
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15
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Snaith HA, Thompson J, Yates JR, Sawin KE. Characterization of Mug33 reveals complementary roles for actin cable-dependent transport and exocyst regulators in fission yeast exocytosis. J Cell Sci 2011; 124:2187-99. [PMID: 21652630 PMCID: PMC3113670 DOI: 10.1242/jcs.084038] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Although endocytosis and exocytosis have been extensively studied in budding yeast, there have been relatively few investigations of these complex processes in the fission yeast Schizosaccharomyces pombe. Here we identify and characterize fission yeast Mug33, a novel Tea1-interacting protein, and show that Mug33 is involved in exocytosis. Mug33 is a Sur7/PalI-family transmembrane protein that localizes to the plasma membrane at the cell tips and to cytoplasmic tubulovesicular elements (TVEs). A subset of Mug33 TVEs make long-range movements along actin cables, co-translocating with subunits of the exocyst complex. TVE movement depends on the type V myosin Myo52. Although mug33Δ mutants are viable, with only a mild cell-polarity phenotype, mug33Δ myo52Δ double mutants are synthetically lethal. Combining mug33 Δ with deletion of the formin For3 (for3Δ) leads to synthetic temperature-sensitive growth and strongly reduced levels of exocytosis. Interestingly, mutants in non-essential genes involved in exocyst function behave in a manner similar to mug33Δ when combined with myo52Δ and for3Δ. By contrast, combining mug33Δ with mutants in non-essential exocyst genes has only minor effects on growth. We propose that Mug33 contributes to exocyst function and that actin cable-dependent vesicle transport and exocyst function have complementary roles in promoting efficient exocytosis in fission yeast.
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Affiliation(s)
- Hilary A Snaith
- Wellcome Trust Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Swann Building, Mayfield Road, Edinburgh EH93JR, UK
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Hosiner D, Sponder G, Graschopf A, Reipert S, Schweyen RJ, Schüller C, Aleschko M. Pun1p is a metal ion-inducible, calcineurin/Crz1p-regulated plasma membrane protein required for cell wall integrity. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1808:1108-19. [PMID: 21223946 PMCID: PMC3062784 DOI: 10.1016/j.bbamem.2011.01.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/20/2010] [Revised: 12/22/2010] [Accepted: 01/03/2011] [Indexed: 12/02/2022]
Abstract
Under conditions of environmental stress, the plasma membrane is involved in several regulatory processes to promote cell survival, like maintenance of signaling pathways, cell wall organization and intracellular ion homeostasis. PUN1 encodes a plasma membrane protein localizing to the ergosterol-rich membrane compartment occupied also by the arginine permease Can1. We found that the PUN1 (YLR414c) gene is transcriptionally induced upon metal ion stress. Northern blot analysis of the transcriptional regulation of PUN1 showed that the calcium dependent transcription factor Crz1p is required for PUN1 induction upon heavy metal stress. Here we report that mutants deleted for PUN1 exhibit increased metal ion sensitivity and morphological abnormalities. Microscopical and ultrastructural observations revealed a severe cell wall defect of pun1∆ mutants. By using chemical cross-linking, Blue native electrophoresis, and co-immunoprecipitation we found that Pun1p forms homo-oligomeric protein complexes. We propose that Pun1p is a stress-regulated factor required for cell wall integrity, thereby expanding the functional significance of lateral plasma membrane compartments.
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Affiliation(s)
- Dagmar Hosiner
- Department of Microbiology, Immunobiology and Genetics, University of Vienna, A-1030 Vienna, Austria
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Bernardo SM, Lee SA. Candida albicans SUR7 contributes to secretion, biofilm formation, and macrophage killing. BMC Microbiol 2010; 10:133. [PMID: 20433738 PMCID: PMC2887802 DOI: 10.1186/1471-2180-10-133] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2009] [Accepted: 04/30/2010] [Indexed: 12/13/2022] Open
Abstract
Background Candida albicans SUR7 has been shown to be required for plasma membrane organization and cell wall synthesis, but its role in virulence is not known. Using a bioinformatics strategy, we previously identified several novel putative secretion pathway proteins potentially involved in virulence, including the C. albicans homolog of the Saccharomyces cerevisiae endocytosis-related protein Sur7p. We therefore generated a C. albicans sur7Δ null mutant and examined its contribution to key virulence attributes. Results Structurally, the C. albicans sur7Δ mutant was impaired in response to filamentation-inducing conditions, and formed aberrant hyphae with extensive accumulation of plasma membrane-derived structures within the cell. Absence of SUR7 resulted in a temperature-sensitive growth defect at high temperatures (42°C), which was partially rescued by addition of NaCl. We next examined the role of the SUR7 paralog C. albicans FMP45 in this temperature-sensitive phenotype. Analysis of C. albicans Fmp45p-GFP demonstrated co-localization of Fmp45p with Sur7p and increased fluorescence in the plasma membrane in the presence of high salt. We next focused on key virulence-related phenotypes. The C. albicans sur7Δ null mutant exhibited secretory defects: reduced lipase secretion, and increased levels of secreted Sap2p. The null mutant was hyper-susceptible to sub-inhibitory concentrations of caspofungin, but not amphotericin B and 5-fluorocytosine. Functionally, the sur7Δ mutant demonstrated increased adhesion to polystyrene and of note, was markedly defective in biofilm formation. In an in vitro macrophage model of virulence, the sur7Δ mutant was impaired in macrophage killing. Conclusions Plasma membrane and cell wall organization are important for cell morphology, and alterations of these structures contributed to impairment of several key virulence-associated phenotypes in the C. albicans sur7Δ mutant.
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Affiliation(s)
- Stella M Bernardo
- Section of Infectious Diseases, New Mexico Veterans Healthcare System, Albuquerque, NM, USA
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18
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A 1.1-kilobase region downstream of the bin operon in Bacillus sphaericus strain 2362 decreases bin yield and crystal size in strain 2297. Appl Environ Microbiol 2008; 75:878-81. [PMID: 19060165 DOI: 10.1128/aem.01444-08] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The 2297 strain of Bacillus sphaericus produces a crystal of the Bin (binary) toxin that is approximately fourfold larger than that of strain 2362, the strain currently used in VectoLex, a commercial mosquito larvicide. Comparison of the regions downstream from the bin operon in these two strains showed that strain 2362 contained a 1.6-kb region with four orf genes not found in strain 2297. Insertion of a 1.1-kb portion of this region from strain 2362 by homologous recombination downstream from the bin operon in strain 2297 reduced Bin toxin production by 50 to 70% and toxicity to fourth-instar larvae of Culex quinquefasciatus by 68%. These results suggest that the 1.6-kb region downstream from the bin operon in B. sphaericus 2362 is responsible for the lower Bin yield and smaller crystal size characteristic of this strain.
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Alvarez FJ, Douglas LM, Rosebrock A, Konopka JB. The Sur7 protein regulates plasma membrane organization and prevents intracellular cell wall growth in Candida albicans. Mol Biol Cell 2008; 19:5214-25. [PMID: 18799621 DOI: 10.1091/mbc.e08-05-0479] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The Candida albicans plasma membrane plays important roles in cell growth and as a target for antifungal drugs. Analysis of Ca-Sur7 showed that this four transmembrane domain protein localized to stable punctate patches, similar to the plasma membrane subdomains known as eisosomes or MCC that were discovered in S. cerevisiae. The localization of Ca-Sur7 depended on sphingolipid synthesis. In contrast to S. cerevisiae, a C. albicans sur7Delta mutant displayed defects in endocytosis and morphogenesis. Septins and actin were mislocalized, and cell wall synthesis was very abnormal, including long projections of cell wall into the cytoplasm. Several phenotypes of the sur7Delta mutant are similar to the effects of inhibiting beta-glucan synthase, suggesting that the abnormal cell wall synthesis is related to activation of chitin synthase activity seen under stress conditions. These results expand the roles of eisosomes by demonstrating that Sur7 is needed for proper plasma membrane organization and cell wall synthesis. A conserved Cys motif in the first extracellular loop of fungal Sur7 proteins is similar to a characteristic motif of the claudin proteins that form tight junctions in animal cells, suggesting a common role for these tetraspanning membrane proteins in forming specialized plasma membrane domains.
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Affiliation(s)
- Francisco J Alvarez
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, NY 11794-5222, USA
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Ren G, Vajjhala P, Lee JS, Winsor B, Munn AL. The BAR domain proteins: molding membranes in fission, fusion, and phagy. Microbiol Mol Biol Rev 2006; 70:37-120. [PMID: 16524918 PMCID: PMC1393252 DOI: 10.1128/mmbr.70.1.37-120.2006] [Citation(s) in RCA: 147] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The Bin1/amphiphysin/Rvs167 (BAR) domain proteins are a ubiquitous protein family. Genes encoding members of this family have not yet been found in the genomes of prokaryotes, but within eukaryotes, BAR domain proteins are found universally from unicellular eukaryotes such as yeast through to plants, insects, and vertebrates. BAR domain proteins share an N-terminal BAR domain with a high propensity to adopt alpha-helical structure and engage in coiled-coil interactions with other proteins. BAR domain proteins are implicated in processes as fundamental and diverse as fission of synaptic vesicles, cell polarity, endocytosis, regulation of the actin cytoskeleton, transcriptional repression, cell-cell fusion, signal transduction, apoptosis, secretory vesicle fusion, excitation-contraction coupling, learning and memory, tissue differentiation, ion flux across membranes, and tumor suppression. What has been lacking is a molecular understanding of the role of the BAR domain protein in each process. The three-dimensional structure of the BAR domain has now been determined and valuable insight has been gained in understanding the interactions of BAR domains with membranes. The cellular roles of BAR domain proteins, characterized over the past decade in cells as distinct as yeasts, neurons, and myocytes, can now be understood in terms of a fundamental molecular function of all BAR domain proteins: to sense membrane curvature, to bind GTPases, and to mold a diversity of cellular membranes.
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Affiliation(s)
- Gang Ren
- Institute for Molecular Bioscience, University of Queensland, St. Lucia, Queensland 4072, Australia
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21
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Walther TC, Brickner JH, Aguilar PS, Bernales S, Pantoja C, Walter P. Eisosomes mark static sites of endocytosis. Nature 2006; 439:998-1003. [PMID: 16496001 DOI: 10.1038/nature04472] [Citation(s) in RCA: 263] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2005] [Accepted: 11/16/2005] [Indexed: 11/09/2022]
Abstract
Endocytosis functions to recycle plasma membrane components, to regulate cell-surface expression of signalling receptors and to internalize nutrients in all eukaryotic cells. Internalization of proteins, lipids and other cargo can occur by one of several pathways that have different, but often overlapping, molecular requirements. To mediate endocytosis, effectors assemble transiently underneath the plasma membrane, carry out the mechanics of membrane deformation, cargo selection and vesicle internalization, and then disassemble. The mechanism by which endocytosis initiates at particular locations on the plasma membrane has remained unknown. Sites of endocytosis might be formed randomly, induced by stochastic protein and/or lipid clustering. Alternatively, endocytosis might initiate at specific locations. Here we describe large immobile protein assemblies at the plasma membrane in the yeast Saccharomyces cerevisiae that mark endocytic sites. These structures, termed eisosomes (from the Greek 'eis', meaning into or portal, and 'soma', meaning body), are composed primarily of two cytoplasmic proteins, Pil1 and Lsp1. A plasma membrane protein, Sur7, localizes to eisosomes. These structures colocalize with sites of protein and lipid endocytosis, and their components genetically interact with known endocytic effectors. Loss of Pil1 leads to clustering of eisosome remnants and redirects endocytosis and endocytic effector proteins to these clusters.
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Affiliation(s)
- Tobias C Walther
- Howard Hughes Medical Institute and Department of Biochemistry and Biophysics, University of California at San Francisco, 600-16th Street, San Francisco, California 94143-2200, USA.
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22
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Germann M, Swain E, Bergman L, Nickels JT. Characterizing the sphingolipid signaling pathway that remediates defects associated with loss of the yeast amphiphysin-like orthologs, Rvs161p and Rvs167p. J Biol Chem 2004; 280:4270-8. [PMID: 15561700 DOI: 10.1074/jbc.m412454200] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Loss of function of either the RVS161 or RVS167 Saccharomyces cerevisiae amphiphysin-like gene confers similar growth phenotypes that can be suppressed by mutations in sphingolipid biosynthesis. We performed a yeast two-hybrid screen using Rvs161p as bait to uncover proteins involved in this sphingolipid-dependent suppressor pathway. In the process, we have demonstrated a direct physical interaction between Rvs167p and the two-hybrid interacting proteins, Acf2p, Gdh3p, and Ybr108wp, while also elucidating the Rvs167p amino acid domains to which these proteins bind. By using subcellular fractionation, we demonstrate that Rvs167p, Ybr108wp, Gdh3p, and Acf2p all localize to Rvs161p-containing lipid rafts, thus placing them within a single compartment that should facilitate their interactions. Moreover, our results suggest that Acf2p and Gdh3p functions are needed for suppressor pathway activity. To determine pathway mechanisms further, we examined the localization of Rvs167p in suppressor mutants. These studies reveal roles for Rvs161p and the very long chain fatty acid elongase, Sur4p, in the localization and/or stability of Rvs167p. Previous yeast studies showed that rvs defects could be suppressed by changes in sphingolipid metabolism brought about by deleting SUR4 (Desfarges, L., Durrens, P., Juguelin, H., Cassagne, C., Bonneu, M., and Aigle, M. (1993) Yeast 9, 267-277). Using rvs167 sur4 and rvs161 sur4 double null cells as models to study suppressor pathway activity, we demonstrate that loss of SUR4 does not remediate the steady-state actin cytoskeletal defects of rvs167 or rvs161 cells. Moreover, suppressor activity does not require the function of the actin-binding protein, Abp1p, or Sla1p, a protein that is thought to regulate assembly of the cortical actin cytoskeleton. Based on our results, we suggest that sphingolipid-dependent suppression of rvs defects may not work entirely through regulating changes in actin organization.
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Affiliation(s)
- Melody Germann
- Department of Biochemistry, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, USA
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Balguerie A, Bagnat M, Bonneu M, Aigle M, Breton AM. Rvs161p and sphingolipids are required for actin repolarization following salt stress. EUKARYOTIC CELL 2002; 1:1021-31. [PMID: 12477802 PMCID: PMC138763 DOI: 10.1128/ec.1.6.1021-1031.2002] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In Saccharomyces cerevisiae, the actin cytoskeleton is depolarized by NaCl stress. In this study, the response was maximal after 30 min, and then actin patches repolarized. Rvs161p was required for actin repolarization because the rvs161delta mutant did not repolarize actin patches after growth in a salt medium. Mutations suppressing the rvs161delta-related salt sensitivity all occurred in genes required for sphingolipid biosynthesis: FEN1, SUR4, SUR2, SUR1, and IPT1. These suppressors also suppressed act1-1-related salt sensitivity and the defect in actin repolarization of the rvs161delta mutant, providing a link between sphingolipids and actin polarization. Indeed, deletion of the suppressor genes suppressed the rvs161delta defect in actin repolarization in two ways: either actin was not depolarized at the wild-type level in a set of suppressor mutants, or actin was repolarized in the absence of Rvs161p in the other suppressor mutants. Rvs161p was localized as cortical patches that concentrated at polarization sites, i.e., bud emergence and septa, and was found to be associated with lipid rafts. An important link between sphingolipids and actin polarization is that Rvs161p was required for actin repolarization and was found to be located in lipid rafts.
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Affiliation(s)
- Axelle Balguerie
- Institut de Biochimie et Génétique Cellulaires, CNRS UMR 5095, F-33077 Bordeaux Cedex, France
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Young ME, Karpova TS, Brügger B, Moschenross DM, Wang GK, Schneiter R, Wieland FT, Cooper JA. The Sur7p family defines novel cortical domains in Saccharomyces cerevisiae, affects sphingolipid metabolism, and is involved in sporulation. Mol Cell Biol 2002; 22:927-34. [PMID: 11784867 PMCID: PMC133540 DOI: 10.1128/mcb.22.3.927-934.2002] [Citation(s) in RCA: 105] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We have discovered a novel cortical patch structure in Saccharomyces cerevisiae defined by a family of integral plasma membrane proteins, including Sur7p, Ynl194p, and Ydl222p. Sur7p-family patches localized as cortical patches that were immobile and stable. These patches were polarized to regions of the cell with a mature cell wall; they were absent from small buds and the tips of many medium-sized buds. These patches were distinct from other known cortical structures. Digestion of the cell wall caused Sur7p patches to disassemble, indicating that Sur7p requires cell wall-dependent extracellular interactions for its localization as patches. sur7Delta, ydl222Delta, and ynl194Delta mutants had reduced sporulation efficiencies. SUR7 was originally described as a multicopy suppressor of rvs167, whose product is an actin patch component. This suppression is probably mediated by sphingolipids, since deletion of SUR7, YDL222, and YNL194 altered the sphingolipid content of the yeast plasma membrane, and other SUR genes suppress rvs167 via effects on sphingolipid synthesis. In particular, the sphingoid base length and number of hydroxyl groups in inositol phosphorylceramides were altered in sur7Delta, ydl222Delta, and yne194Delta strains.
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Affiliation(s)
- Michael E Young
- Department of Cell Biology and Physiology, Washington University, St. Louis, Missouri 63110, USA
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25
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Molecular transformation, gene cloning, and gene expression systems for filamentous fungi. ACTA ACUST UNITED AC 2001. [DOI: 10.1016/s1874-5334(01)80010-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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26
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Abstract
Much recent research on c-Myc has focused on how it drives apoptosis. c-Myc is widely known as a crucial regulator of cell proliferation in normal and neoplastic cells, but until relatively recently its apoptotic properties, which appear to be intrinsic, were not fully appreciated. Its death-dealing aspects have gained wide attention in part because of their potential therapeutic utility in advanced malignancy, where c-Myc is frequently deregulated and where novel modalities are badly needed. Although its exact function remains obscure, c-Myc is a transcription factor and advances have been made in characterizing target genes which may mediate its apoptotic properties. Candidate regulators and effectors are also emerging. Among recent findings are connections to the CD95/Fas and TNF pathways and roles for the tumor suppressor p19ARF and the c-Myc-interacting adaptor protein Binl in mediating cell death. In this review I summarize the data establishing a role for c-Myc in apoptosis in diverse settings and present a modified dual signal model for c-Myc function. It is proposed that c-Myc induces apoptosis through separate 'death priming' and 'death triggering' mechanisms in which 'death priming' and mitogenic signals are coordinated. Investigation of the mechanisms that underlie the triggering steps may offer new therapeutic opportunities.
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Brizzio V, Gammie AE, Rose MD. Rvs161p interacts with Fus2p to promote cell fusion in Saccharomyces cerevisiae. J Biophys Biochem Cytol 1998; 141:567-84. [PMID: 9566960 PMCID: PMC2132759 DOI: 10.1083/jcb.141.3.567] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
FUS7 was previously identified by a mutation that causes a defect in cell fusion in a screen for bilateral mating defects. Here we show that FUS7 is allelic to RVS161/END6, a gene implicated in a variety of processes including viability after starvation, endocytosis, and actin cytoskeletal organization. Two lines of evidence indicate that RVS161/END6's endocytic function is not required for cell fusion. First, several other endocytic mutants showed no cell fusion defects. Second, we isolated five function-specific alleles of RVS161/FUS7 that were defective for endocytosis, but not mating, and three alleles that were defective for cell fusion but not endocytosis. The organization of the actin cytoskeleton was normal in the cell fusion mutants, indicating that Rvs161p's function in cell fusion is independent of actin organization. The three to fourfold induction of RVS161 by mating pheromone and the localization of Rvs161p-GFP to the cell fusion zone suggested that Rvs161p plays a direct role in cell fusion. The phenotypes of double mutants, the coprecipitation of Rvs161p and Fus2p, and the fact that the stability of Fus2p was strongly dependent on Rvs161p's mating function lead to the conclusion that Rvs161p is required to interact with Fus2p for efficient cell fusion.
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Affiliation(s)
- V Brizzio
- Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544-1014, USA
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28
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Abstract
Mutations in RVS161 and RVS167 yeast genes induce identical phenotypes associated to actin cytoskeleton disorders. The whole Rvs161 protein is similar to the amino-terminal part of Rvs167p, thus defining a RVS domain. In addition to this domain, Rvs167p contains a central glycine-proline-alanine rich domain and a SH3 domain. To assess the function of these different domains we have expressed recombinant Rvs proteins in rvs mutant strains. Phenotype analysis has shown that the RVS and SH3 domains are necessary for phenotypical complementation, whereas the GPA domain is not. Moreover, we have demonstrated that the RVS domains from Rvs161p and Rvs167p have distinct roles, and that the SH3 domain needs the specific RVS domain of Rvs167p to function. These results suggest that Rvs161p and Rvs167p play distinct roles, while acting together in a common function.
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Affiliation(s)
- P Sivadon
- Laboratoire de Biologie Cellulaire de la Levure, IBGC UPR CNRS 9026, Bordeaux, France
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