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Dai M, Liu X, Goldman GH, Lu L, Zhang S. The EH domain-containing protein, EdeA, is involved in endocytosis, cell wall integrity, and pathogenicity in Aspergillus fumigatus. mSphere 2024; 9:e0005724. [PMID: 38687129 DOI: 10.1128/msphere.00057-24] [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: 01/29/2024] [Accepted: 03/29/2024] [Indexed: 05/02/2024] Open
Abstract
Endocytosis has been extensively studied in yeasts, where it plays crucial roles in growth, signaling regulation, and cell-surface receptor internalization. However, the biological functions of endocytosis in pathogenic filamentous fungi remain largely unexplored. In this study, we aimed to functionally characterize the roles of EdeA, an ortholog of the Saccharomyces cerevisiae endocytic protein Ede1, in Aspergillus fumigatus. EdeA was observed to be distributed as patches on the plasma membrane and concentrated in the subapical collar of hyphae, a localization characteristic of endocytic proteins. Loss of edeA caused defective hyphal polarity, reduced conidial production, and fewer sites of endocytosis initiations than that of the parental wild type. Notably, the edeA null mutant exhibited increased sensitivity to cell wall-disrupting agents, indicating a role for EdeA in maintaining cell wall integrity in A. fumigatus. This observation was further supported by the evidence showing that the thickness of the cell wall in the ΔedeA mutant increased, accompanied by abnormal activation of MpkA, a key component in the cell wall integrity pathway. Additionally, the ΔedeA mutant displayed increased pathogenicity in the Galleria mellonella wax moth infection model, possibly due to alterations in cell wall morphology. Site-directed mutagenesis identified the conserved residue E348 within the third EH (Eps15 homology) domain of EdeA as crucial for its subcellular localization and functions. In conclusion, our results highlight the involvement of EdeA in endocytosis, hyphal polarity, cell wall integrity, and pathogenicity in A. fumigatus. IMPORTANCE Aspergillus fumigatus is a significant human pathogenic fungus known to cause invasive aspergillosis, a disease with a high mortality rate. Understanding the basic principles of A. fumigatus pathogenicity is crucial for developing effective strategies against this pathogen. Previous research has underscored the importance of endocytosis in the infection capacity of pathogenic yeasts; however, its biological function in pathogenic mold remains largely unexplored. Our characterization of EdeA in A. fumigatus sheds light on the role of endocytosis in the development, stress response, and pathogenicity of pathogenic molds. These findings suggest that the components of the endocytosis process may serve as potential targets for antifungal therapy.
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Affiliation(s)
- Mengyao Dai
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Centre for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Xintian Liu
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Centre for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Gustavo H Goldman
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Ling Lu
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Centre for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Shizhu Zhang
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Centre for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing, China
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2
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Brauer VS, Pessoni AM, Freitas MS, Cavalcanti-Neto MP, Ries LNA, Almeida F. Chitin Biosynthesis in Aspergillus Species. J Fungi (Basel) 2023; 9:jof9010089. [PMID: 36675910 PMCID: PMC9865612 DOI: 10.3390/jof9010089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 12/14/2022] [Accepted: 12/17/2022] [Indexed: 01/11/2023] Open
Abstract
The fungal cell wall (FCW) is a dynamic structure responsible for the maintenance of cellular homeostasis, and is essential for modulating the interaction of the fungus with its environment. It is composed of proteins, lipids, pigments and polysaccharides, including chitin. Chitin synthesis is catalyzed by chitin synthases (CS), and up to eight CS-encoding genes can be found in Aspergillus species. This review discusses in detail the chitin synthesis and regulation in Aspergillus species, and how manipulation of chitin synthesis pathways can modulate fungal growth, enzyme production, virulence and susceptibility to antifungal agents. More specifically, the metabolic steps involved in chitin biosynthesis are described with an emphasis on how the initiation of chitin biosynthesis remains unknown. A description of the classification, localization and transport of CS was also made. Chitin biosynthesis is shown to underlie a complex regulatory network, with extensive cross-talks existing between the different signaling pathways. Furthermore, pathways and recently identified regulators of chitin biosynthesis during the caspofungin paradoxical effect (CPE) are described. The effect of a chitin on the mammalian immune system is also discussed. Lastly, interference with chitin biosynthesis may also be beneficial for biotechnological applications. Even after more than 30 years of research, chitin biosynthesis remains a topic of current interest in mycology.
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Affiliation(s)
- Veronica S. Brauer
- Department of Biochemistry and Immunology, Ribeirao Preto Medical School, University of Sao Paulo, Sao Paulo 01000-000, Brazil
| | - André M. Pessoni
- Department of Biochemistry and Immunology, Ribeirao Preto Medical School, University of Sao Paulo, Sao Paulo 01000-000, Brazil
| | - Mateus S. Freitas
- Department of Biochemistry and Immunology, Ribeirao Preto Medical School, University of Sao Paulo, Sao Paulo 01000-000, Brazil
| | - Marinaldo P. Cavalcanti-Neto
- Integrated Laboratory of Morphofunctional Sciences, Institute of Biodiversity and Sustainability (NUPEM), Federal University of Rio de Janeiro, Rio de Janeiro 27965-045, Brazil
| | - Laure N. A. Ries
- MRC Centre for Medical Mycology, University of Exeter, Exeter EX4 4QD, UK
- Correspondence: (L.N.A.R.); (F.A.)
| | - Fausto Almeida
- Department of Biochemistry and Immunology, Ribeirao Preto Medical School, University of Sao Paulo, Sao Paulo 01000-000, Brazil
- Correspondence: (L.N.A.R.); (F.A.)
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3
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Arakawa S, Kanaseki T, Wagner R, Goodenough U. Ultrastructure of the foliose lichen Myelochroa leucotyliza and its solo fungal and algal (Trebouxia sp.) partners. ALGAL RES 2022. [DOI: 10.1016/j.algal.2021.102571] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
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4
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Faoro F, Faccio A, Balestrini R. Contributions of Ultrastructural Studies to the Knowledge of Filamentous Fungi Biology and Fungi-Plant Interactions. FRONTIERS IN FUNGAL BIOLOGY 2022; 2:805739. [PMID: 37744126 PMCID: PMC10512230 DOI: 10.3389/ffunb.2021.805739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Accepted: 12/14/2021] [Indexed: 09/26/2023]
Abstract
Since the first experiments in 1950s, transmission electron microscopy (TEM) observations of filamentous fungi have contributed extensively to understand their structure and to reveal the mechanisms of apical growth. Additionally, also in combination with the use of affinity techniques (such as the gold complexes), several aspects of plant-fungal interactions were elucidated. Nowadays, after the huge of information obtained from -omics techniques, TEM studies and ultrastructural observations offer the possibility to support these data, considering that the full comprehension of the mechanisms at the basis of fungal morphogenesis and the interaction with other organisms is closely related to a detailed knowledge of the structural features. Here, the contribution of these approaches on fungal biology is illustrated, focusing both on hyphae cell ultrastructure and infection structures of pathogenic and mycorrhizal fungi. Moreover, a concise appendix of methods conventionally used for the study of fungal ultrastructure is provided.
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Affiliation(s)
- Franco Faoro
- Dipartimento di Scienze Agrarie e Ambientali, Università di Milano, Milan, Italy
| | - Antonella Faccio
- Consiglio Nazionale delle Ricerche, Istituto per la Protezione Sostenibile delle Piante, Turin, Italy
| | - Raffaella Balestrini
- Consiglio Nazionale delle Ricerche, Istituto per la Protezione Sostenibile delle Piante, Turin, Italy
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5
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Williams T, Parker D, Taubman B. Characterization of Unmalted Barley Treated with Aspergillus oryzae. JOURNAL OF THE AMERICAN SOCIETY OF BREWING CHEMISTS 2021. [DOI: 10.1080/03610470.2021.1978045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Tom Williams
- A.R. Smith Department of Chemistry and Fermentation Sciences, Appalachian State University, Boone, NC, U.S.A
| | - Daniel Parker
- A.R. Smith Department of Chemistry and Fermentation Sciences, Appalachian State University, Boone, NC, U.S.A
| | - Brett Taubman
- A.R. Smith Department of Chemistry and Fermentation Sciences, Appalachian State University, Boone, NC, U.S.A
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6
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Tracking Fungal Growth: Establishment of Arp1 as a Marker for Polarity Establishment and Active Hyphal Growth in Filamentous Ascomycetes. J Fungi (Basel) 2021; 7:jof7070580. [PMID: 34356959 PMCID: PMC8304394 DOI: 10.3390/jof7070580] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 07/16/2021] [Accepted: 07/18/2021] [Indexed: 12/20/2022] Open
Abstract
Polar growth is a key characteristic of all filamentous fungi. It allows these eukaryotes to not only effectively explore organic matter but also interact within its own colony, mating partners, and hosts. Therefore, a detailed understanding of the dynamics in polar growth establishment and maintenance is crucial for several fields of fungal research. We developed a new marker protein, the actin-related protein 1 (Arp1) fused to red and green fluorescent proteins, which allows for the tracking of polar axis establishment and active hyphal growth in microscopy approaches. To exclude a probable redundancy with known polarity markers, we compared the localizations of the Spitzenkörper (SPK) and Arp1 using an FM4-64 staining approach. As we show in applications with the coprophilous fungus Sordaria macrospora and the hemibiotrophic plant pathogen Colletotrichum graminicola, the monitoring of Arp1 can be used for detailed studies of hyphal growth dynamics and ascospore germination, the interpretation of chemotropic growth processes, and the tracking of elongating penetration pegs into plant material. Since the Arp1 marker showed the same dynamics in both fungi tested, we believe this marker can be broadly applied in fungal research to study the manifold polar growth processes determining fungal life.
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Baltussen TJH, Coolen JPM, Verweij PE, Dijksterhuis J, Melchers WJG. Identifying Conserved Generic Aspergillus spp. Co-Expressed Gene Modules Associated with Germination Using Cross-Platform and Cross-Species Transcriptomics. J Fungi (Basel) 2021; 7:270. [PMID: 33916245 PMCID: PMC8067318 DOI: 10.3390/jof7040270] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 03/27/2021] [Accepted: 03/29/2021] [Indexed: 12/26/2022] Open
Abstract
Aspergillus spp. is an opportunistic human pathogen that may cause a spectrum of pulmonary diseases. In order to establish infection, inhaled conidia must germinate, whereby they break dormancy, start to swell, and initiate a highly polarized growth process. To identify critical biological processes during germination, we performed a cross-platform, cross-species comparative analysis of germinating A. fumigatus and A. niger conidia using transcriptional data from published RNA-Seq and Affymetrix studies. A consensus co-expression network analysis identified four gene modules associated with stages of germination. These modules showed numerous shared biological processes between A. niger and A. fumigatus during conidial germination. Specifically, the turquoise module was enriched with secondary metabolism, the black module was highly enriched with protein synthesis, the darkgreen module was enriched with protein fate, and the blue module was highly enriched with polarized growth. More specifically, enriched functional categories identified in the blue module were vesicle formation, vesicular transport, tubulin dependent transport, actin-dependent transport, exocytosis, and endocytosis. Genes important for these biological processes showed similar expression patterns in A. fumigatus and A. niger, therefore, they could be potential antifungal targets. Through cross-platform, cross-species comparative analysis, we were able to identify biologically meaningful modules shared by A. fumigatus and A. niger, which underscores the potential of this approach.
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Affiliation(s)
- Tim J. H. Baltussen
- Department of Medical Microbiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands; (J.P.M.C.); (P.E.V.); (W.J.G.M.)
- Center of Expertise in Mycology Radboudumc/CWZ, 6532 SZ Nijmegen, The Netherlands
| | - Jordy P. M. Coolen
- Department of Medical Microbiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands; (J.P.M.C.); (P.E.V.); (W.J.G.M.)
- Center of Expertise in Mycology Radboudumc/CWZ, 6532 SZ Nijmegen, The Netherlands
| | - Paul E. Verweij
- Department of Medical Microbiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands; (J.P.M.C.); (P.E.V.); (W.J.G.M.)
- Center of Expertise in Mycology Radboudumc/CWZ, 6532 SZ Nijmegen, The Netherlands
| | - Jan Dijksterhuis
- Westerdijk Fungal Biodiversity Institute, 3584 CT Utrecht, The Netherlands
| | - Willem J. G. Melchers
- Department of Medical Microbiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands; (J.P.M.C.); (P.E.V.); (W.J.G.M.)
- Center of Expertise in Mycology Radboudumc/CWZ, 6532 SZ Nijmegen, The Netherlands
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8
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Silva PM, Puerner C, Seminara A, Bassilana M, Arkowitz RA. Secretory Vesicle Clustering in Fungal Filamentous Cells Does Not Require Directional Growth. Cell Rep 2020; 28:2231-2245.e5. [PMID: 31433995 DOI: 10.1016/j.celrep.2019.07.062] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2018] [Revised: 04/22/2019] [Accepted: 07/18/2019] [Indexed: 11/27/2022] Open
Abstract
During symmetry breaking, the highly conserved Rho GTPase Cdc42 becomes stabilized at a defined site via an amplification process. However, little is known about how a new polarity site is established in an already asymmetric cell-a critical process in a changing environment. The human fungal pathogen Candida albicans switches from budding to filamentous growth in response to external cues, a transition controlled by Cdc42. Here, we have used optogenetic manipulation of cell polarity to reset growth in asymmetric filamentous C. albicans cells. We show that increasing the level of active Cdc42 on the plasma membrane results in disruption of the exocyst subunit Sec3 localization and a striking de novo clustering of secretory vesicles. This new cluster of secretory vesicles is highly dynamic, moving by hops and jumps, until a new growth site is established. Our results reveal that secretory vesicle clustering can occur in the absence of directional growth.
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Affiliation(s)
- Patrícia M Silva
- Université Côte d'Azur, CNRS, INSERM, Institute of Biology Valrose (iBV), Parc Valrose, Nice, France
| | - Charles Puerner
- Université Côte d'Azur, CNRS, INSERM, Institute of Biology Valrose (iBV), Parc Valrose, Nice, France
| | - Agnese Seminara
- Université Côte d'Azur, CNRS, Institute Physics of Nice (INPHYNI), Ave. J. Vallot, Nice, France
| | - Martine Bassilana
- Université Côte d'Azur, CNRS, INSERM, Institute of Biology Valrose (iBV), Parc Valrose, Nice, France
| | - Robert A Arkowitz
- Université Côte d'Azur, CNRS, INSERM, Institute of Biology Valrose (iBV), Parc Valrose, Nice, France.
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9
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Chelius C, Huso W, Reese S, Doan A, Lincoln S, Lawson K, Tran B, Purohit R, Glaros T, Srivastava R, Harris SD, Marten MR. Dynamic Transcriptomic and Phosphoproteomic Analysis During Cell Wall Stress in Aspergillus nidulans. Mol Cell Proteomics 2020; 19:1310-1329. [PMID: 32430394 PMCID: PMC8014999 DOI: 10.1074/mcp.ra119.001769] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 03/30/2020] [Indexed: 12/15/2022] Open
Abstract
The fungal cell-wall integrity signaling (CWIS) pathway regulates cellular response to environmental stress to enable wall repair and resumption of normal growth. This complex, interconnected, pathway has been only partially characterized in filamentous fungi. To better understand the dynamic cellular response to wall perturbation, a β-glucan synthase inhibitor (micafungin) was added to a growing A. nidulans shake-flask culture. From this flask, transcriptomic and phosphoproteomic data were acquired over 10 and 120 min, respectively. To differentiate statistically-significant dynamic behavior from noise, a multivariate adaptive regression splines (MARS) model was applied to both data sets. Over 1800 genes were dynamically expressed and over 700 phosphorylation sites had changing phosphorylation levels upon micafungin exposure. Twelve kinases had altered phosphorylation and phenotypic profiling of all non-essential kinase deletion mutants revealed putative connections between PrkA, Hk-8-4, and Stk19 and the CWIS pathway. Our collective data implicate actin regulation, endocytosis, and septum formation as critical cellular processes responding to activation of the CWIS pathway, and connections between CWIS and calcium, HOG, and SIN signaling pathways.
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Affiliation(s)
- Cynthia Chelius
- Department of Chemical, Biochemical, and Environmental Engineering, University of Maryland Baltimore County, Baltimore, Maryland, USA
| | - Walker Huso
- Department of Chemical, Biochemical, and Environmental Engineering, University of Maryland Baltimore County, Baltimore, Maryland, USA
| | - Samantha Reese
- Center for Plant Science Innovation and Department of Plant Pathology, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
| | - Alexander Doan
- Department of Chemical, Biochemical, and Environmental Engineering, University of Maryland Baltimore County, Baltimore, Maryland, USA
| | - Stephen Lincoln
- Department of Chemical and Biomolecular Engineering, University of Connecticut, Storrs, Connecticut, USA
| | - Kelsi Lawson
- Department of Chemical, Biochemical, and Environmental Engineering, University of Maryland Baltimore County, Baltimore, Maryland, USA
| | - Bao Tran
- BioScience Mass Spectrometry Facility, The U.S. Army CCDC Chemical Biological Center, BioSciences Division, Aberdeen Proving Ground, Maryland, USA
| | - Raj Purohit
- Department of Chemical, Biochemical, and Environmental Engineering, University of Maryland Baltimore County, Baltimore, Maryland, USA
| | - Trevor Glaros
- BioSciences Division, B11 Bioenergy and Biome Sciences, Los Alamos National Laboratory, Los Alamos, New Mexico, USA
| | - Ranjan Srivastava
- Department of Chemical and Biomolecular Engineering, University of Connecticut, Storrs, Connecticut, USA
| | - Steven D Harris
- Department of Biological Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Mark R Marten
- Department of Chemical, Biochemical, and Environmental Engineering, University of Maryland Baltimore County, Baltimore, Maryland, USA.
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10
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Kunz PJ, Barthel L, Meyer V, King R. Vesicle transport and growth dynamics in Aspergillus niger: Microscale modeling of secretory vesicle flow and centerline extraction from confocal fluorescent data. Biotechnol Bioeng 2020; 117:2875-2886. [PMID: 32510171 DOI: 10.1002/bit.27452] [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: 07/08/2019] [Revised: 05/27/2020] [Accepted: 05/30/2020] [Indexed: 12/15/2022]
Abstract
In this paper, we present a mathematical model to describe filamentous fungal growth based on intracellular secretory vesicles (SVs), which transport cell wall components to the hyphal tip. Vesicular transport inside elongating hyphae is modeled as an advection-diffusion-reaction equation with a moving boundary, transformed into fixed coordinates, and discretized using a high-order weighted essentially nonoscillatory discretization scheme. The model describes the production and the consumption of SVs with kinetic functions. Simulations are subsequently compared against distributions of SVs visualized by enhanced green fluorescent protein in young Aspergillus niger hyphae after germination. Intensity profile data are obtained using an algorithm scripted in ImageJ that extracts mean intensity distributions from 3D time-lapse confocal measurement data. Simulated length growth is in good agreement with the experimental data. Our simulations further show that a decrease of effective vesicle transport velocity towards the tip can explain the observed tip accumulation of SVs.
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Affiliation(s)
- Philipp J Kunz
- Chair of Measurement and Control, Technische Universität Berlin, Berlin, Germany
| | - Lars Barthel
- Chair of Applied and Molecular Microbiology, Technische Universität Berlin, Berlin, Germany
| | - Vera Meyer
- Chair of Applied and Molecular Microbiology, Technische Universität Berlin, Berlin, Germany
| | - Rudibert King
- Chair of Measurement and Control, Technische Universität Berlin, Berlin, Germany
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11
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Commer B, Schultzhaus Z, Shaw BD. Localization of NPFxD motif-containing proteins in Aspergillus nidulans. Fungal Genet Biol 2020; 141:103412. [PMID: 32445863 DOI: 10.1016/j.fgb.2020.103412] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 05/04/2020] [Accepted: 05/10/2020] [Indexed: 12/28/2022]
Abstract
During growth, filamentous fungi produce polarized cells called hyphae. It is generally presumed that polarization of hyphae is dependent upon secretion through the Spitzenkörper, as well as a mechanism called apical recycling, which maintains a balance between the tightly coupled processes of endocytosis and exocytosis. Endocytosis predominates in an annular domain called the sub-apical endocytic collar, which is located in the region of plasma membrane 1-5 μm distal to the Spitzenkörper. It has previously been proposed that one function of the sub-apical endocytic collar is to maintain the apical localization of polarization proteins. These proteins mark areas of polarization at the apices of hyphae. However, as hyphae grow, these proteins are displaced along the membrane and some must then be removed at the sub-apical endocytic collar in order to maintain the hyphoid shape. While endocytosis is fairly well characterized in yeast, comparatively little is known about the process in filamentous fungi. Here, a bioinformatics approach was utilized to identify 39 Aspergillus nidulans proteins that are predicted to be cargo of endocytosis based on the presence of an NPFxD peptide motif. This motif is a necessary endocytic signal sequence first established in Saccharomyces cerevisiae, where it marks proteins for endocytosis through an interaction with the adapter protein Sla1p. It is hypothesized that some proteins that contain this NPFxD peptide sequence in A. nidulans will be potential targets for endocytosis, and therefore will localize either to the endocytic collar or to more proximal polarized regions of the cell, e.g. the apical dome or the Spitzenkörper. To test this, a subset of the motif-containing proteins in A. nidulans was tagged with GFP and the dynamic localization was evaluated. The documented localization patterns support the hypothesis that the motif marks proteins for localization to the polarized cell apex in growing hyphae.
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Affiliation(s)
- Blake Commer
- Department of Plant Pathology and Microbiology, Texas A&M University, 2132 TAMU, College Station, TX 77843, USA.
| | - Zachary Schultzhaus
- Department of Plant Pathology and Microbiology, Texas A&M University, 2132 TAMU, College Station, TX 77843, USA.
| | - Brian D Shaw
- Department of Plant Pathology and Microbiology, Texas A&M University, 2132 TAMU, College Station, TX 77843, USA.
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12
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Wang Q, Zhong C, Xiao H. Genetic Engineering of Filamentous Fungi for Efficient Protein Expression and Secretion. Front Bioeng Biotechnol 2020; 8:293. [PMID: 32322579 PMCID: PMC7156587 DOI: 10.3389/fbioe.2020.00293] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 03/19/2020] [Indexed: 02/05/2023] Open
Abstract
Filamentous fungi are considered as unique cell factories for protein production due to the high efficiency of protein secretion and superior capability of post-translational modifications. In this review, we firstly introduce the secretory pathway in filamentous fungi. We next summarize the current state-of-the-art works regarding how various genetic engineering strategies are applied for enhancing protein expression and secretion in filamentous fungi. Finally, in a future perspective, we discuss the great potential of genome engineering for further improving protein expression and secretion in filamentous fungi.
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Affiliation(s)
- Qin Wang
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, and Laboratory of Molecular Biochemical Engineering, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Chao Zhong
- Materials and Physical Biology Division, School of Physical Science and Technology, ShanghaiTech University, Shanghai, China
- Materials Synthetic Biology Center, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Han Xiao
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, and Laboratory of Molecular Biochemical Engineering, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
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13
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Abstract
Filamentous fungi grow by adding cell wall and membrane exclusively at the apex of tubular structures called hyphae. Growth was previously believed to occur only through exocytosis at the Spitzenkörper, an organised body of secretory macro- and microvesicles found only in growing hyphae. More recent work has indicated that an area deemed the sub-apical collar is enriched for endocytosis and is also required for hyphal growth. It is now generally believed that polarity of filamentous fungi is achieved through the balancing of the processes of endocytosis and exocytosis at these two areas. This review is an update on the current progress and understanding surrounding the occurrence of endocytosis and its spatial regulation as they pertain to growth and pathogenicity in filamentous fungi.
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Affiliation(s)
- Blake Commer
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX, USA
| | - Brian D Shaw
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX, USA
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14
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Comparative genomics reveals the origin of fungal hyphae and multicellularity. Nat Commun 2019; 10:4080. [PMID: 31501435 PMCID: PMC6733946 DOI: 10.1038/s41467-019-12085-w] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Accepted: 08/20/2019] [Indexed: 02/01/2023] Open
Abstract
Hyphae represent a hallmark structure of multicellular fungi. The evolutionary origins of hyphae and of the underlying genes are, however, hardly known. By systematically analyzing 72 complete genomes, we here show that hyphae evolved early in fungal evolution probably via diverse genetic changes, including co-option and exaptation of ancient eukaryotic (e.g. phagocytosis-related) genes, the origin of new gene families, gene duplications and alterations of gene structure, among others. Contrary to most multicellular lineages, the origin of filamentous fungi did not correlate with expansions of kinases, receptors or adhesive proteins. Co-option was probably the dominant mechanism for recruiting genes for hypha morphogenesis, while gene duplication was apparently less prevalent, except in transcriptional regulators and cell wall - related genes. We identified 414 novel gene families that show correlated evolution with hyphae and that may have contributed to its evolution. Our results suggest that hyphae represent a unique multicellular organization that evolved by limited fungal-specific innovations and gene duplication but pervasive co-option and modification of ancient eukaryotic functions.
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Córdova-Alcántara IM, Venegas-Cortés DL, Martínez-Rivera MÁ, Pérez NO, Rodriguez-Tovar AV. Biofilm characterization of Fusarium solani keratitis isolate: increased resistance to antifungals and UV light. J Microbiol 2019; 57:485-497. [DOI: 10.1007/s12275-019-8637-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 01/23/2019] [Accepted: 01/28/2019] [Indexed: 12/27/2022]
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16
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Feng Z, Tian J, Han L, Geng Y, Sun J, Kong Z. The Myosin5-mediated actomyosin motility system is required for Verticillium
pathogenesis of cotton. Environ Microbiol 2018; 20:1607-1621. [DOI: 10.1111/1462-2920.14101] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Revised: 03/05/2018] [Accepted: 03/11/2018] [Indexed: 11/30/2022]
Affiliation(s)
- Zhidi Feng
- The Key Laboratory of Oasis Eco-Agriculture; College of Agriculture, Shihezi University; Shihezi Xinjiang 832000 China
- State Key Laboratory of Plant Genomic; Institute of Microbiology, Chinese Academy of Sciences; Beijing 100101 China
| | - Juan Tian
- State Key Laboratory of Plant Genomic; Institute of Microbiology, Chinese Academy of Sciences; Beijing 100101 China
| | - Libo Han
- State Key Laboratory of Plant Genomic; Institute of Microbiology, Chinese Academy of Sciences; Beijing 100101 China
| | - Yuan Geng
- State Key Laboratory of Plant Genomic; Institute of Microbiology, Chinese Academy of Sciences; Beijing 100101 China
| | - Jie Sun
- The Key Laboratory of Oasis Eco-Agriculture; College of Agriculture, Shihezi University; Shihezi Xinjiang 832000 China
| | - Zhaosheng Kong
- State Key Laboratory of Plant Genomic; Institute of Microbiology, Chinese Academy of Sciences; Beijing 100101 China
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17
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Glory A, van Oostende CT, Geitmann A, Bachewich C. Depletion of the mitotic kinase Cdc5p in Candida albicans results in the formation of elongated buds that switch to the hyphal fate over time in a Ume6p and Hgc1p-dependent manner. Fungal Genet Biol 2017; 107:51-66. [DOI: 10.1016/j.fgb.2017.08.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Revised: 07/27/2017] [Accepted: 08/08/2017] [Indexed: 10/19/2022]
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18
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Abstract
The molecular composition of the cell wall is critical for the biology and ecology of each fungal species. Fungal walls are composed of matrix components that are embedded and linked to scaffolds of fibrous load-bearing polysaccharides. Most of the major cell wall components of fungal pathogens are not represented in humans, other mammals, or plants, and therefore the immune systems of animals and plants have evolved to recognize many of the conserved elements of fungal walls. For similar reasons the enzymes that assemble fungal cell wall components are excellent targets for antifungal chemotherapies and fungicides. However, for fungal pathogens, the cell wall is often disguised since key signature molecules for immune recognition are sometimes masked by immunologically inert molecules. Cell wall damage leads to the activation of sophisticated fail-safe mechanisms that shore up and repair walls to avoid catastrophic breaching of the integrity of the surface. The frontiers of research on fungal cell walls are moving from a descriptive phase defining the underlying genes and component parts of fungal walls to more dynamic analyses of how the various components are assembled, cross-linked, and modified in response to environmental signals. This review therefore discusses recent advances in research investigating the composition, synthesis, and regulation of cell walls and how the cell wall is targeted by immune recognition systems and the design of antifungal diagnostics and therapeutics.
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Abstract
ABSTRACT
The fungal lineage is one of the three large eukaryotic lineages that dominate terrestrial ecosystems. They share a common ancestor with animals in the eukaryotic supergroup Opisthokonta and have a deeper common ancestry with plants, yet several phenotypes, such as morphological, physiological, or nutritional traits, make them unique among all living organisms. This article provides an overview of some of the most important fungal traits, how they evolve, and what major genes and gene families contribute to their development. The traits highlighted here represent just a sample of the characteristics that have evolved in fungi, including polarized multicellular growth, fruiting body development, dimorphism, secondary metabolism, wood decay, and mycorrhizae. However, a great number of other important traits also underlie the evolution of the taxonomically and phenotypically hyperdiverse fungal kingdom, which could fill up a volume on its own. After reviewing the evolution of these six well-studied traits in fungi, we discuss how the recurrent evolution of phenotypic similarity, that is, convergent evolution in the broad sense, has shaped their phylogenetic distribution in extant species.
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20
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Abstract
The molecular composition of the cell wall is critical for the biology and ecology of each fungal species. Fungal walls are composed of matrix components that are embedded and linked to scaffolds of fibrous load-bearing polysaccharides. Most of the major cell wall components of fungal pathogens are not represented in humans, other mammals, or plants, and therefore the immune systems of animals and plants have evolved to recognize many of the conserved elements of fungal walls. For similar reasons the enzymes that assemble fungal cell wall components are excellent targets for antifungal chemotherapies and fungicides. However, for fungal pathogens, the cell wall is often disguised since key signature molecules for immune recognition are sometimes masked by immunologically inert molecules. Cell wall damage leads to the activation of sophisticated fail-safe mechanisms that shore up and repair walls to avoid catastrophic breaching of the integrity of the surface. The frontiers of research on fungal cell walls are moving from a descriptive phase defining the underlying genes and component parts of fungal walls to more dynamic analyses of how the various components are assembled, cross-linked, and modified in response to environmental signals. This review therefore discusses recent advances in research investigating the composition, synthesis, and regulation of cell walls and how the cell wall is targeted by immune recognition systems and the design of antifungal diagnostics and therapeutics.
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Affiliation(s)
- Neil A R Gow
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen AB252ZD, United Kingdom
| | | | - Carol A Munro
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen AB252ZD, United Kingdom
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21
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Martin-Yken H, François JM, Zerbib D. Knr4: a disordered hub protein at the heart of fungal cell wall signalling. Cell Microbiol 2016; 18:1217-27. [PMID: 27199081 DOI: 10.1111/cmi.12618] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 05/14/2016] [Accepted: 05/17/2016] [Indexed: 02/05/2023]
Abstract
The most highly connected proteins in protein-protein interactions networks are called hubs; they generally connect signalling pathways. In Saccharomyces cerevisiae, Knr4 constitutes a connecting node between the two main signal transmission pathways involved in cell wall maintenance upon stress: the cell wall integrity and the calcium-calcineurin pathway. Knr4 is required to enable the cells to resist many cell wall-affecting stresses, and KNR4 gene deletion is synthetic lethal with the simultaneous deletion of numerous other genes involved in morphogenesis and cell wall biogenesis. Knr4 has been shown to engage in multiple physical interactions, an ability conferred by the intrinsic structural adaptability of major disordered regions present in the N-terminal and C-terminal parts of the protein. Taking all together, Knr4 is an intrinsically disordered hub protein. Available data from other fungi indicate the conservation of Knr4 homologs cellular function and localization at sites of polarized growth among fungal species, including pathogenic species. Because of their particular role in morphogenesis control and of their fungal specificity, these proteins could constitute interesting new pharmaceutical drug targets for antifungal combination therapy.
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Affiliation(s)
- Hélène Martin-Yken
- LISBP, Université Fédérale de Toulouse, CNRS, INRA, INSA, 135 Avenue de Rangueil, F-31077, Toulouse, France
| | - Jean Marie François
- LISBP, Université Fédérale de Toulouse, CNRS, INRA, INSA, 135 Avenue de Rangueil, F-31077, Toulouse, France
| | - Didier Zerbib
- LISBP, Université Fédérale de Toulouse, CNRS, INRA, INSA, 135 Avenue de Rangueil, F-31077, Toulouse, France.,Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, UPS, F-31077, Toulouse, France
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22
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Guo M, Kilaru S, Schuster M, Latz M, Steinberg G. Fluorescent markers for the Spitzenkörper and exocytosis in Zymoseptoria tritici. Fungal Genet Biol 2016; 79:158-65. [PMID: 26092802 PMCID: PMC4502456 DOI: 10.1016/j.fgb.2015.04.014] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Revised: 04/10/2015] [Accepted: 04/13/2015] [Indexed: 11/25/2022]
Abstract
We establish Z. tritici polarity markers ZtSec4, ZtMlc1, ZtRab11, ZtExo70 and ZtSpa2. All markers localize correctly, labeling the Spitzenkörper and sites of polar exocytosis. We provide 5 carboxin-resistance conveying vectors for integration of all markers into the sdi1 locus. We provide 5 hygromycin B-resistance conveying vectors for random integration of all markers.
Fungal hyphae are highly polarized cells that invade their substrate by tip growth. In plant pathogenic fungi, hyphal growth is essential for host invasion. This makes polarity factors and secretion regulators potential new targets for novel fungicides. Polarization requires delivery of secretory vesicles to the apical Spitzenkörper, followed by polarized exocytosis at the expanding cell tip. Here, we introduce fluorescent markers to visualize the apical Spitzenkörper and the apical site of exocytosis in hyphae of the wheat pathogen Zymoseptoria tritici. We fused green fluorescent protein to the small GTPase ZtSec4, the myosin light chain ZtMlc1 and the small GTPase ZtRab11 and co-localize the fusion proteins with the dye FM4-64 in the hyphal apex, suggesting that the markers label the hyphal Spitzenkörper in Z. tritici. In addition, we localize GFP-fusions to the exocyst protein ZtExo70, the polarisome protein ZtSpa2. Consistent with results in the ascomycete Neurospora crassa, these markers did localize near the plasma membrane at the hyphal tip and only partially co-localize with FM4-64. Thus, these fluorescent markers are useful molecular tools that allow phenotypic analysis of mutants in Z. tritici. These tools will help develop new avenues of research in our quest to control STB infection in wheat.
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Affiliation(s)
- M Guo
- School of Biosciences, University of Exeter, Exeter EX4 4QD, UK
| | - S Kilaru
- School of Biosciences, University of Exeter, Exeter EX4 4QD, UK
| | - M Schuster
- School of Biosciences, University of Exeter, Exeter EX4 4QD, UK
| | - M Latz
- School of Biosciences, University of Exeter, Exeter EX4 4QD, UK
| | - G Steinberg
- School of Biosciences, University of Exeter, Exeter EX4 4QD, UK.
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23
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Fisher KE, Roberson RW. Hyphal tip cytoplasmic organization in four zygomycetous fungi. Mycologia 2016; 108:533-42. [PMID: 26908648 DOI: 10.3852/15-226] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 02/11/2016] [Indexed: 11/10/2022]
Abstract
We have examined the hyphal tip structure in four zygomycetous fungi: Mortierella verticillata (Mortierellales), Coemansia reversa (Kickxellales), Mucor indicus and Gilbertella persicaria (Mucorales) using both light and transmission electron microscopy. We have used cryofixation and freeze-substitution methods to preserve fungal hyphae for transmission electron microscopy, which yielded improved preservation of ultrastructural details. Our research has confirmed studies that described the accumulation of secretory vesicles as a crescent at the hyphal apex (i.e. the apical vesicle crescent [AVC]) and provided a more detailed understanding of the vesicle populations. In addition, we have been able to observe the behavior of the AVC during hyphal growth in M. indicus and G. persicaria.
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Affiliation(s)
- Karen E Fisher
- School of Life Sciences, Arizona State University, Tempe, Arizona 85287
| | - Robert W Roberson
- School of Life Sciences, Arizona State University, Tempe, Arizona 85287
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24
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Stable Pseudohyphal Growth in Budding Yeast Induced by Synergism between Septin Defects and Altered MAP-kinase Signaling. PLoS Genet 2015; 11:e1005684. [PMID: 26640955 PMCID: PMC4671653 DOI: 10.1371/journal.pgen.1005684] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 10/29/2015] [Indexed: 11/19/2022] Open
Abstract
Upon nutrient limitation, budding yeasts like Saccharomyces cerevisiae can be induced to adopt alternate filament-like growth patterns called diploid pseudohyphal or invasive haploid growth. Here, we report a novel constitutive pseudohyphal growth state, sharing some characteristics with classic forms of filamentous growth, but differing in crucial aspects of morphology, growth conditions and genetic regulation. The constitutive pseudohyphal state is observed in fus3 mutants containing various septin assembly defects, which we refer to as sadF growth (septin assembly defect induced filamentation) to distinguish it from classic filamentation pathways. Similar to other filamentous states, sadF cultures comprise aggregated chains of highly elongated cells. Unlike the classic pathways, sadF growth occurs in liquid rich media, requiring neither starvation nor the key pseudohyphal proteins, Flo8p and Flo11p. Moreover sadF growth occurs in haploid strains of S288C genetic background, which normally cannot undergo pseudohyphal growth. The sadF cells undergo highly polarized bud growth during prolonged G2 delays dependent on Swe1p. They contain septin structures distinct from classical pseudo-hyphae and FM4-64 labeling at actively growing tips similar to the Spitzenkörper observed in true hyphal growth. The sadF growth state is induced by synergism between Kss1p-dependent signaling and septin assembly defects; mild disruption of mitotic septins activates Kss1p-dependent gene expression, which exacerbates the septin defects, leading to hyper-activation of Kss1p. Unlike classical pseudo-hyphal growth, sadF signaling requires Ste5, Ste4 and Ste18, the scaffold protein and G-protein β and γ subunits from the pheromone response pathway, respectively. A swe1 mutation largely abolished signaling, breaking the positive feedback that leads to amplification of sadF signaling. Taken together, our findings show that budding yeast can access a stable constitutive pseudohyphal growth state with very few genetic and regulatory changes. Many pathogenic fungi alternate between unicellular and multicellular filamentous forms, which is often critical for host-cell attachment, tissue invasion, and virulence. Certain strains of the nonpathogenic budding yeast Saccharomyces cerevisiae are also capable of forming invasive pseudohyphal filaments in nutrient poor conditions, which has served as a model system for the study of filamentous fungal pathogens. Here, we show that the most commonly used laboratory strain, S288c, previously known as being non-filamentous, can adopt a permanent stable pseudohyphal growth phase even under rich growth conditions. Although some features are shared, the degree of filamentation, genetic requirements, cell cycle, and mechanism of regulation are distinct from the previously described forms of filamentous growth. Stable pseudohyphal growth arises as a result of only two mutations, neither of which causes pseudohyphal growth on their own. One mutation causes subtle defects in the mechanism of cell separation (septation), which activate intracellular signaling pathways that slow cell division and promote filamentation. Normally this pathway is kept in check by a related signaling protein. However, when the inhibitor is also defective, activation of the filamentation signaling pathway exacerbates the septation defects, which causes a synergistic hyper-activation of pseudohyphal growth. These findings expand our understanding of fungal pathogenesis mechanisms at the molecular level.
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25
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Chen X, Ebbole DJ, Wang Z. The exocyst complex: delivery hub for morphogenesis and pathogenesis in filamentous fungi. CURRENT OPINION IN PLANT BIOLOGY 2015; 28:48-54. [PMID: 26453967 DOI: 10.1016/j.pbi.2015.09.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2015] [Revised: 08/30/2015] [Accepted: 09/05/2015] [Indexed: 06/05/2023]
Abstract
Regulated by several small GTPases, the octameric exocyst complex directs the docking and tethering of exocytic vesicles to the destined plasma membrane sites, providing the precise spatiotemporal control of exocytosis. Although the exocyst components are well conserved among various fungal species, the mechanisms for the regulation of its assembly and activity are diverse. Exocytosis is crucial for the generation of cell polarity as well as the delivery of effector proteins in filamentous fungi, and thus plays an important role for fungal morphogenesis and pathogenicity on plant hosts. This review focuses on current findings about the roles of the exocyst complex in the morphogenesis and pathogenesis of filamentous fungi.
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Affiliation(s)
- Xiaofeng Chen
- Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry University, Fuzhou 350002, China; Fujian Province Key Laboratory of Pathogenic Fungi and Mycotoxins, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Daniel J Ebbole
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77843, USA
| | - Zonghua Wang
- Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry University, Fuzhou 350002, China; Fujian Province Key Laboratory of Pathogenic Fungi and Mycotoxins, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
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26
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Perdoni F, Signorelli P, Cirasola D, Caretti A, Galimberti V, Biggiogera M, Gasco P, Musicanti C, Morace G, Borghi E. Antifungal activity of Myriocin on clinically relevant Aspergillus fumigatus strains producing biofilm. BMC Microbiol 2015; 15:248. [PMID: 26519193 PMCID: PMC4628231 DOI: 10.1186/s12866-015-0588-0] [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: 05/04/2015] [Accepted: 10/23/2015] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND The human pathogenic mold Aspergillus fumigatus is able to form a complex biofilm embedded in extracellular matrix. Biofilms confer antimicrobial resistance and it is well known that aspergillosis is often refractory to the conventional antifungal therapy. The treatment of biofilm-related infections poses a significant clinical challenge on a daily basis, promoting the search for new therapeutic agents. Our aim was to exploit the modulation of sphingolipid mediators as new therapeutic target to overcome antifungal resistance in biofilm-related infections. RESULTS Antifungal susceptibility testing was performed on 20 clinical isolates of Aspergillus fumigatus and one reference strain (A. fumigatus Af293) according the EUCAST protocol. Sessile MICs were assessed on 24-h preformed-biofilm by means of XTT-reduction assay. Myriocin (0.25-64 mg/L), a commercial sphingolipid synthesis inhibitor, was used. The MEC50 value (mg/L) of Myriocin was 8 (range 4-16) for both planktonic and sessile cells. Drug-induced morphological alterations were analyzed by optical and electron microscopy (TEM) on 24h preformed A. fumigatus Af293 biofilms. An evident hyphal damage, resulting in short, stubby, and highly branched hyphae was observed by optical microscopy. At 24h, TEM studies showed important morphological alterations, such as invaginations of the cell membrane, modification in the vacuolar system and presence of multilamellar bodies, in some cases within vacuoles. CONCLUSIONS The direct antifungal activity, observed on both planktonic and sessile fungi, suggests that inhibition of sphingolipid synthesis could represent a new target to fight biofilm-related A. fumigatus resistance.
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Affiliation(s)
- Federica Perdoni
- Department of Health Sciences, Università degli Studi di Milano, Polo Universitario San Paolo, Blocco C, ottavo piano, via di Rudinì 8, 20142, Milan, Italy.
| | - Paola Signorelli
- Department of Health Sciences, Università degli Studi di Milano, Polo Universitario San Paolo, Blocco C, ottavo piano, via di Rudinì 8, 20142, Milan, Italy.
| | - Daniela Cirasola
- Department of Health Sciences, Università degli Studi di Milano, Polo Universitario San Paolo, Blocco C, ottavo piano, via di Rudinì 8, 20142, Milan, Italy.
| | - Anna Caretti
- Department of Health Sciences, Università degli Studi di Milano, Polo Universitario San Paolo, Blocco C, ottavo piano, via di Rudinì 8, 20142, Milan, Italy.
| | - Valentina Galimberti
- Department of Biology and Biotechnology, Università degli Studi di Pavia, Pavia, Italy.
| | - Marco Biggiogera
- Department of Biology and Biotechnology, Università degli Studi di Pavia, Pavia, Italy.
| | | | | | - Giulia Morace
- Department of Health Sciences, Università degli Studi di Milano, Polo Universitario San Paolo, Blocco C, ottavo piano, via di Rudinì 8, 20142, Milan, Italy.
| | - Elisa Borghi
- Department of Health Sciences, Università degli Studi di Milano, Polo Universitario San Paolo, Blocco C, ottavo piano, via di Rudinì 8, 20142, Milan, Italy.
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27
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Abstract
Only few Candida species, e.g., Candida albicans, Candida glabrata, Candida dubliniensis, and Candida parapsilosis, are successful colonizers of a human host. Under certain circumstances these species can cause infections ranging from superficial to life-threatening disseminated candidiasis. The success of C. albicans, the most prevalent and best studied Candida species, as both commensal and human pathogen depends on its genetic, biochemical, and morphological flexibility which facilitates adaptation to a wide range of host niches. In addition, formation of biofilms provides additional protection from adverse environmental conditions. Furthermore, in many host niches Candida cells coexist with members of the human microbiome. The resulting fungal-bacterial interactions have a major influence on the success of C. albicans as commensal and also influence disease development and outcome. In this chapter, we review the current knowledge of important survival strategies of Candida spp., focusing on fundamental fitness and virulence traits of C. albicans.
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Affiliation(s)
- Melanie Polke
- Research Group Microbial Immunology, Hans-Knoell-Institute, Jena, Germany; Department Microbial Pathogenicity Mechanisms, Hans-Knoell-Institute, Jena, Germany
| | - Bernhard Hube
- Department Microbial Pathogenicity Mechanisms, Hans-Knoell-Institute, Jena, Germany; Friedrich-Schiller-University, Jena, Germany; Center for Sepsis Control and Care, Jena University Hospital, Jena, Germany
| | - Ilse D Jacobsen
- Research Group Microbial Immunology, Hans-Knoell-Institute, Jena, Germany; Friedrich-Schiller-University, Jena, Germany
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28
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Colabardini AC, Ries LNA, Brown NA, Savoldi M, Dinamarco TM, von Zeska MR, Goldman MHS, Goldman GH. Protein kinase C overexpression suppresses calcineurin-associated defects in Aspergillus nidulans and is involved in mitochondrial function. PLoS One 2014; 9:e104792. [PMID: 25153325 PMCID: PMC4143261 DOI: 10.1371/journal.pone.0104792] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2014] [Accepted: 07/11/2014] [Indexed: 12/22/2022] Open
Abstract
In filamentous fungi, intracellular signaling pathways which are mediated by changing calcium levels and/or by activated protein kinase C (Pkc), control fungal adaptation to external stimuli. A rise in intracellular Ca2+ levels activates calcineurin subunit A (CnaA), which regulates cellular calcium homeostasis among other processes. Pkc is primarily involved in maintaining cell wall integrity (CWI) in response to different environmental stresses. Cross-talk between the Ca2+ and Pkc-mediated pathways has mainly been described in Saccharomyces cerevisiae and in a few other filamentous fungi. The presented study describes a genetic interaction between CnaA and PkcA in the filamentous fungus Aspergillus nidulans. Overexpression of pkcA partially rescues the phenotypes caused by a cnaA deletion. Furthermore, CnaA appears to affect the regulation of a mitogen-activated kinase, MpkA, involved in the CWI pathway. Reversely, PkcA is involved in controlling intracellular calcium homeostasis, as was confirmed by microarray analysis. Furthermore, overexpression of pkcA in a cnaA deletion background restores mitochondrial number and function. In conclusion, PkcA and CnaA-mediated signaling appear to share common targets, one of which appears to be MpkA of the CWI pathway. Both pathways also regulate components involved in mitochondrial biogenesis and function. This study describes targets for PkcA and CnaA-signaling pathways in an A. nidulans and identifies a novel interaction of both pathways in the regulation of cellular respiration.
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Affiliation(s)
- Ana Cristina Colabardini
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | | | - Neil Andrew Brown
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - Marcela Savoldi
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - Taísa Magnani Dinamarco
- Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - Marcia Regina von Zeska
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - Maria Helena S. Goldman
- Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - Gustavo Henrique Goldman
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol – CTBE, Campinas, São Paulo, Brazil
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
- * E-mail:
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29
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Riquelme M, Sánchez-León E. The Spitzenkörper: a choreographer of fungal growth and morphogenesis. Curr Opin Microbiol 2014; 20:27-33. [DOI: 10.1016/j.mib.2014.04.003] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Revised: 04/24/2014] [Accepted: 04/25/2014] [Indexed: 01/07/2023]
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30
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Bernardo SM, Rane HS, Chavez-Dozal A, Lee SA. Secretion and filamentation are mediated by the Candida albicans t-SNAREs Sso2p and Sec9p. FEMS Yeast Res 2014; 14:762-75. [PMID: 24911595 DOI: 10.1111/1567-1364.12165] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Revised: 05/14/2014] [Accepted: 05/14/2014] [Indexed: 12/12/2022] Open
Abstract
To study the role of late secretion in Candida albicans pathogenesis, we created conditional mutant C. albicans strains in which the t-SNARE-encoding genes SSO2 or SEC9 were placed under the control of a tetracycline-regulated promoter. In repressing conditions, C. albicans tetR-SSO2 and tetR-SEC9 mutant strains were defective in cytokinesis and secretion of aspartyl proteases and lipases. The mutant strains also exhibited a defect in filamentation compared with controls, and thus, we followed the fate of the C. albicans Spitzenkörper, an assembly of secretory vesicles thought to act as a vesicle supply center for the growing hyphae. In the absence of Ca Sso2p, the Spitzenkörper dissipated within 5 h and thin-section electron microscopy revealed an accumulation of secretory vesicles. Moreover, the hyphal tip developed into a globular yeast-like structure rather than maintaining a typical narrow hyphae. These studies indicate that late secretory t-SNARE proteins in C. albicans are required for fundamental cellular processes and contribute to virulence-related attributes of C. albicans pathogenesis. Moreover, these results provide direct evidence for a key role of SNARE proteins in vesicle-mediated polarized hyphal growth of C. albicans.
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Affiliation(s)
- Stella M Bernardo
- Section of Infectious Diseases, New Mexico Veterans Healthcare System, Albuquerque, NM, USA; University of New Mexico Health Science Center, Albuquerque, NM, USA
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31
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Functional analysis of BcBem1 and its interaction partners in Botrytis cinerea: impact on differentiation and virulence. PLoS One 2014; 9:e95172. [PMID: 24797931 PMCID: PMC4010548 DOI: 10.1371/journal.pone.0095172] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Accepted: 03/24/2014] [Indexed: 11/19/2022] Open
Abstract
In phytopathogenic fungi the establishment and maintenance of polarity is not only essential for vegetative growth and differentiation, but also for penetration and colonization of host tissues. We investigated orthologs of members of the yeast polarity complex in the grey mould fungus Botrytis cinerea: the scaffold proteins Bem1 and Far1, the GEF (guanine nucleotide exchange factor) Cdc24, and the formin Bni1 (named Sep1 in B. cinerea). BcBem1 does not play an important role in regular hyphal growth, but has significant impact on spore formation and germination, on the establishment of conidial anastomosis tubes (CATs) and on virulence. As in other fungi, BcBem1 interacts with the GEF BcCdc24 and the formin BcSep1, indicating that in B. cinerea the apical complex has a similar structure as in yeast. A functional analysis of BcCdc24 suggests that it is essential for growth, since it was not possible to obtain homokaryotic deletion mutants. Heterokaryons of Δcdc24 (supposed to exhibit reduced bccdc24 transcript levels) already show a strong phenotype: an inability to penetrate the host tissue, a significantly reduced growth rate and malformation of conidia, which tend to burst as observed for Δbcbem1. Also the formin BcSep1 has significant impact on hyphal growth and development, whereas the role of the putative ortholog of the yeast scaffold protein Far1 remains open: Δbcfar1 mutants have no obvious phenotypes.
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Sen A, Mukherjee D, Aguilar RC. Bem3: Filling the GAP between cell polarity and secretion. Commun Integr Biol 2013; 6:e26702. [PMID: 24753785 PMCID: PMC3984288 DOI: 10.4161/cib.26702] [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: 10/02/2013] [Accepted: 10/04/2013] [Indexed: 11/19/2022] Open
Abstract
A highly conserved member of the Rho family of small GTPases, Cdc42 functions as the "master regulator of cell polarity." It has been reported that for proper establishment and maintenance of cell polarity, Cdc42 regulates and requires vesicle trafficking. Importantly, we recently discovered that in budding yeast, vesicle trafficking also controls the localization and function of Bem3, a GTPase activating protein for Cdc42. Specifically, we observed that Bem3 partitioned between the plasma membrane and an internal membrane-bound compartment. This Bem3-containing compartment was present during extended periods of apical growth, required actin tracks for trafficking to polarized sites and functioned as a recycling station that was positioned at the junction of endocytic and secretory pathways. Strikingly, many of these features are reminiscent of the Spitzenkörper, a dynamic structure involved in polarized growth during hyphal development in several filamentous fungi. Furthermore, Bem3 was not merely a passive cargo but actively recruited the secretory Rab GTPase Sec4 to this Spitzenkörper-like compartment. Importantly, this function of Bem3 was independent of its GAP activity. Our work demonstrates the existence of a complementary regulation between Bem3, a regulator of Cdc42 signaling and Sec4, a key component of the secretory machinery.
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Affiliation(s)
- Arpita Sen
- Department of Biological Sciences; Purdue University; West Lafayette, IN USA
| | | | - R Claudio Aguilar
- Department of Biological Sciences; Purdue University; West Lafayette, IN USA
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Mukherjee D, Sen A, Boettner DR, Fairn GD, Schlam D, Bonilla Valentin FJ, Michael McCaffery J, Hazbun T, Staiger CJ, Grinstein S, Lemmon SK, Claudio Aguilar R. Bem3, a Cdc42 GTPase-activating protein, traffics to an intracellular compartment and recruits the secretory Rab GTPase Sec4 to endomembranes. J Cell Sci 2013; 126:4560-71. [PMID: 23943876 DOI: 10.1242/jcs.117663] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Cell polarity is essential for many cellular functions including division and cell-fate determination. Although RhoGTPase signaling and vesicle trafficking are both required for the establishment of cell polarity, the mechanisms by which they are coordinated are unclear. Here, we demonstrate that the yeast RhoGAP (GTPase activating protein), Bem3, is targeted to sites of polarized growth by the endocytic and recycling pathways. Specifically, deletion of SLA2 or RCY1 led to mislocalization of Bem3 to depolarized puncta and accumulation in intracellular compartments, respectively. Bem3 partitioned between the plasma membrane and an intracellular membrane-bound compartment. These Bem3-positive structures were polarized towards sites of bud emergence and were mostly observed during the pre-mitotic phase of apical growth. Cell biological and biochemical approaches demonstrated that this intracellular Bem3 compartment contained markers for both the endocytic and secretory pathways, which were reminiscent of the Spitzenkörper present in the hyphal tips of growing fungi. Importantly, Bem3 was not a passive cargo, but recruited the secretory Rab protein, Sec4, to the Bem3-containing compartments. Moreover, Bem3 deletion resulted in less efficient localization of Sec4 to bud tips during early stages of bud emergence. Surprisingly, these effects of Bem3 on Sec4 were independent of its GAP activity, but depended on its ability to efficiently bind endomembranes. This work unveils unsuspected and important details of the relationship between vesicle traffic and elements of the cell polarity machinery: (1) Bem3, a cell polarity and peripherally associated membrane protein, relies on vesicle trafficking to maintain its proper localization; and (2) in turn, Bem3 influences secretory vesicle trafficking.
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Affiliation(s)
- Debarati Mukherjee
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
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Wang J, Du Y, Zhang H, Zhou C, Qi Z, Zheng X, Wang P, Zhang Z. The actin-regulating kinase homologue MoArk1 plays a pleiotropic function in Magnaporthe oryzae. MOLECULAR PLANT PATHOLOGY 2013; 14:470-82. [PMID: 23384308 PMCID: PMC3642230 DOI: 10.1111/mpp.12020] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Endocytosis is an essential cellular process in eukaryotic cells that involves concordant functions of clathrin and adaptor proteins, various protein and lipid kinases, phosphatases and the actin cytoskeleton. In Saccharomyces cerevisiae, Ark1p is a member of the serine/threonine protein kinase (SPK) family that affects profoundly the organization of the cortical actin cytoskeleton. To study the function of MoArk1, an Ark1p homologue identified in Magnaporthe oryzae, we disrupted the MoARK1 gene and characterized the ΔMoark1 mutant strain. The ΔMoark1 mutant exhibited various defects ranging from mycelial growth and conidial formation to appressorium-mediated host infection. The ΔMoark1 mutant also exhibited decreased appressorium turgor pressure and attenuated virulence on rice and barley. In addition, the ΔMoark1 mutant displayed defects in endocytosis and formation of the Spitzenkörper, and was hyposensitive to exogenous oxidative stress. Moreover, a MoArk1-green fluorescent protein (MoArk1-GFP) fusion protein showed an actin-like localization pattern by localizing to the apical regions of hyphae. This pattern of localization appeared to be regulated by the N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins MoSec22 and MoVam7. Finally, detailed analysis revealed that the proline-rich region within the MoArk1 serine/threonine kinase (S_TKc) domain was critical for endocytosis, subcellular localization and pathogenicity. These results collectively suggest that MoArk1 exhibits conserved functions in endocytosis and actin cytoskeleton organization, which may underlie growth, cell wall integrity and virulence of the fungus.
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Affiliation(s)
- Jiamei Wang
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China
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Dijksterhuis J, Molenaar D. Vesicle trafficking via the Spitzenkörper during hyphal tip growth in Rhizoctonia solani. Antonie van Leeuwenhoek 2013; 103:921-31. [DOI: 10.1007/s10482-012-9873-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2012] [Accepted: 12/27/2012] [Indexed: 10/27/2022]
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Dettmann A, Illgen J, März S, Schürg T, Fleissner A, Seiler S. The NDR kinase scaffold HYM1/MO25 is essential for MAK2 map kinase signaling in Neurospora crassa. PLoS Genet 2012; 8:e1002950. [PMID: 23028357 PMCID: PMC3447951 DOI: 10.1371/journal.pgen.1002950] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Accepted: 07/30/2012] [Indexed: 12/22/2022] Open
Abstract
Cell communication is essential for eukaryotic development, but our knowledge of molecules and mechanisms required for intercellular communication is fragmentary. In particular, the connection between signal sensing and regulation of cell polarity is poorly understood. In the filamentous ascomycete Neurospora crassa, germinating spores mutually attract each other and subsequently fuse. During these tropic interactions, the two communicating cells rapidly alternate between two different physiological states, probably associated with signal delivery and response. The MAK2 MAP kinase cascade mediates cell–cell signaling. Here, we show that the conserved scaffolding protein HYM1/MO25 controls the cell shape-regulating NDR kinase module as well as the signal-receiving MAP kinase cascade. HYM1 functions as an integral part of the COT1 NDR kinase complex to regulate the interaction with its upstream kinase POD6 and thereby COT1 activity. In addition, HYM1 interacts with NRC1, MEK2, and MAK2, the three kinases of the MAK2 MAP kinase cascade, and co-localizes with MAK2 at the apex of growing cells. During cell fusion, the three kinases of the MAP kinase module as well as HYM1 are recruited to the point of cell–cell contact. hym-1 mutants phenocopy all defects observed for MAK2 pathway mutants by abolishing MAK2 activity. An NRC1-MEK2 fusion protein reconstitutes MAK2 signaling in hym-1, while constitutive activation of NRC1 and MEK2 does not. These data identify HYM1 as a novel regulator of the NRC1-MEK2-MAK2 pathway, which may coordinate NDR and MAP kinase signaling during cell polarity and intercellular communication. Intercellular communication and cellular morphogenesis are essential for eukaryotic development. Our knowledge of molecules and mechanisms associated with these processes is, however, fragmentary. In particular, the molecular connection between signal sensing and regulation of cell polarity is poorly understood. Fungal hyphae share with neurons and pollen tubes the distinction of being amongst the most highly polarized cells in biology. The robust genetic tractability of filamentous fungi provides an unparalleled opportunity to determine common principles that underlie polarized growth and its regulation through cell communication. In Neurospora crassa, germinating spores mutually attract each other, establish physical contact through polarized tropic growth, and fuse. During this process, the cells rapidly alternate between two different physiological states, probably associated with signal delivery and response. Here, we show that the conserved scaffolding protein HYM1/MO25 interacts with the polarity and cell shape-regulating NDR kinase complex as well as a MAP kinase module, which is essential for cell communication during the tropic interaction. We propose that this dual use of a common regulator in both molecular complexes may represent an intriguing mechanism of linking the perception of external cues with the polarization machinery to coordinate communication and tropic growth of interacting cells.
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Affiliation(s)
- Anne Dettmann
- Institute for Microbiology and Genetics, University of Goettingen, Goettingen, Germany
| | - Julia Illgen
- Institute for Genetics, Technische Universität Braunschweig, Braunschweig, Germany
| | - Sabine März
- Institute for Microbiology and Genetics, University of Goettingen, Goettingen, Germany
| | - Timo Schürg
- Institute for Genetics, Technische Universität Braunschweig, Braunschweig, Germany
| | - Andre Fleissner
- Institute for Genetics, Technische Universität Braunschweig, Braunschweig, Germany
| | - Stephan Seiler
- Institute for Microbiology and Genetics, University of Goettingen, Goettingen, Germany
- * E-mail:
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Cloning and characterization of the actin gene from Puccinia striiformis f. sp. tritici. World J Microbiol Biotechnol 2012; 28:2331-9. [DOI: 10.1007/s11274-012-1040-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Accepted: 01/11/2012] [Indexed: 01/25/2023]
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Taheri-Talesh N, Xiong Y, Oakley BR. The functions of myosin II and myosin V homologs in tip growth and septation in Aspergillus nidulans. PLoS One 2012; 7:e31218. [PMID: 22359575 PMCID: PMC3281053 DOI: 10.1371/journal.pone.0031218] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2011] [Accepted: 01/04/2012] [Indexed: 01/05/2023] Open
Abstract
Because of the industrial and medical importance of members of the fungal genus Aspergillus, there is considerable interest in the functions of cytoskeletal components in growth and secretion in these organisms. We have analyzed the genome of Aspergillus nidulans and found that there are two previously unstudied myosin genes, a myosin II homolog, myoB (product = MyoB) and a myosin V homolog, myoE (product = MyoE). Deletions of either cause significant growth defects. MyoB localizes in strings that coalesce into contractile rings at forming septa. It is critical for septation and normal deposition of chitin but not for hyphal extension. MyoE localizes to the Spitzenkörper and to moving puncta in the cytoplasm. Time-lapse imaging of SynA, a v-SNARE, reveals that in myoE deletion strains vesicles no longer localize to the Spitzenkörper. Tip morphology is slightly abnormal and branching occurs more frequently than in controls. Tip extension is slower than in controls, but because hyphal diameter is greater, growth (increase in volume/time) is only slightly reduced. Concentration of vesicles into the Spitzenkörper before incorporation into the plasma membrane is, thus, not required for hyphal growth but facilitates faster tip extension and a more normal hyphal shape.
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Affiliation(s)
- Naimeh Taheri-Talesh
- Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas, United States of America
| | - Yi Xiong
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio, United States of America
| | - Berl R. Oakley
- Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas, United States of America
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio, United States of America
- * E-mail:
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Sánchez-Arreguín A, Pérez-Martínez AS, Herrera-Estrella A. Proteomic analysis of Trichoderma atroviride reveals independent roles for transcription factors BLR-1 and BLR-2 in light and darkness. EUKARYOTIC CELL 2012; 11:30-41. [PMID: 22058143 PMCID: PMC3255938 DOI: 10.1128/ec.05263-11] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2011] [Accepted: 10/24/2011] [Indexed: 11/20/2022]
Abstract
The genus Trichoderma is one of the most widely used biological control agents of plant-pathogenic fungi. The main mechanism for survival and dispersal of Trichoderma is through the production of asexual spores (conidia). The transition from filamentous growth to conidiation can be triggered by light, nutrient deprivation, and mechanical damage of the mycelium. We conducted proteomic profiling analyses of Trichoderma atroviride after a blue light pulse. The use of two-dimensional electrophoresis (2-DE) and mass spectrometry (MS) analysis allowed us to identify 72 proteins whose expression was affected by blue light. Functional category analysis showed that the various proteins are involved in metabolism, cell rescue, and protein synthesis. We determined the relationship between mRNA levels of selected genes 30 min after a light pulse and protein expression levels at different times after the pulse and found this correlation to be very weak. The correlation was highest when protein and mRNA levels were compared for the same time point. The transcription factors BLR-1 and BLR-2 are vital to the photoconidiation process; here we demonstrate that both BLR proteins are active in darkness and affect several elements at both the transcript and protein levels. Unexpectedly, in darkness, downregulation of proteins prevailed in the Δblr-1 mutant, while upregulation of proteins predominated in the Δblr-2 mutant. Our data demonstrate that the BLR proteins play roles individually and as a complex.
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Affiliation(s)
- Alejandro Sánchez-Arreguín
- Laboratorio Nacional de Gnómica para la Biodiversidad, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico National, Irapuato, Guanajuato, México
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Pérez-Martín J. Cell Cycle and Morphogenesis Connections During the Formation of the Infective Filament in Ustilago maydis. TOPICS IN CURRENT GENETICS 2012. [DOI: 10.1007/978-3-642-22916-9_6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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The role of sho1 in polarized growth of Aspergillus fumigatus. Mycopathologia 2011; 172:347-55. [PMID: 21796487 DOI: 10.1007/s11046-011-9452-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2011] [Accepted: 07/14/2011] [Indexed: 10/17/2022]
Abstract
Aspergillus fumigatus is an opportunistic pathogen that may cause severe invasive disease in immunocompromised patients. The filamentous fungi undergo polarized growth, searching for nutrients in the environment and causing invasive growth in tissue. Sho1 is a sensor of the high osmolarity glycerol pathway, and the sho1 mutant showed a decrease in growth rate. We found that sho1 is involved in the polarized growth of A. fumigatus. The sho1 mutation resulted in extended isotropic growth of germinating conidia followed by multiple germ tubes and wide hyphae with short intercalary cells by calcofluor white staining. The mechanism by which sho1 gene affected polarized growth is investigated. A reduced number of apical vesicles with greater dispersion were observed by transmission electron microscopy in the Spitzenkörper body of the sho1 mutant. Actin patches were distributed randomly at low density at early stages of mutant strain fungal development and reaggregated to the hyphal tip of later stages when long filamentous fungi formed. Actin patches located at the tip of polarized wild-type cells. RNA levels of polarized growth-related genes Rho GTPases were detected by real-time PCR. The sho1 gene did not affect the RNA expression when strains were cultured at 37°C for 6 h. At 17 h, the RNA expression of rho1, rho3 and CDC42 in the sho1 mutant were 0.18-, 0.18- and 0.33-fold of that in the wild type. The sho1 gene affected the polarized growth through affecting the expression of Rho GTPases, the distribution of actin cytoskeleton, vesicle quantity and distribution.
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Shapiro RS, Robbins N, Cowen LE. Regulatory circuitry governing fungal development, drug resistance, and disease. Microbiol Mol Biol Rev 2011; 75:213-67. [PMID: 21646428 PMCID: PMC3122626 DOI: 10.1128/mmbr.00045-10] [Citation(s) in RCA: 384] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Pathogenic fungi have become a leading cause of human mortality due to the increasing frequency of fungal infections in immunocompromised populations and the limited armamentarium of clinically useful antifungal drugs. Candida albicans, Cryptococcus neoformans, and Aspergillus fumigatus are the leading causes of opportunistic fungal infections. In these diverse pathogenic fungi, complex signal transduction cascades are critical for sensing environmental changes and mediating appropriate cellular responses. For C. albicans, several environmental cues regulate a morphogenetic switch from yeast to filamentous growth, a reversible transition important for virulence. Many of the signaling cascades regulating morphogenesis are also required for cells to adapt and survive the cellular stresses imposed by antifungal drugs. Many of these signaling networks are conserved in C. neoformans and A. fumigatus, which undergo distinct morphogenetic programs during specific phases of their life cycles. Furthermore, the key mechanisms of fungal drug resistance, including alterations of the drug target, overexpression of drug efflux transporters, and alteration of cellular stress responses, are conserved between these species. This review focuses on the circuitry regulating fungal morphogenesis and drug resistance and the impact of these pathways on virulence. Although the three human-pathogenic fungi highlighted in this review are those most frequently encountered in the clinic, they represent a minute fraction of fungal diversity. Exploration of the conservation and divergence of core signal transduction pathways across C. albicans, C. neoformans, and A. fumigatus provides a foundation for the study of a broader diversity of pathogenic fungi and a platform for the development of new therapeutic strategies for fungal disease.
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Affiliation(s)
| | | | - Leah E. Cowen
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
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The mating projections of Saccharomyces cerevisiae and Candida albicans show key characteristics of hyphal growth. Fungal Biol 2011; 115:547-56. [DOI: 10.1016/j.funbio.2011.02.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2010] [Revised: 02/01/2011] [Accepted: 02/02/2011] [Indexed: 02/06/2023]
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Sudbery P. Fluorescent proteins illuminate the structure and function of the hyphal tip apparatus. Fungal Genet Biol 2011; 48:849-57. [PMID: 21362491 DOI: 10.1016/j.fgb.2011.02.004] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2010] [Revised: 01/25/2011] [Accepted: 02/18/2011] [Indexed: 12/15/2022]
Abstract
Fungal hyphae show extreme polarized growth at the tip. Electron microscope studies have revealed a apical body called the Spitzenkörper that is thought to drive polarized growth. Studies of polarized growth in S. cerevisiae have identified the protein components of the polarized growth machinery, that are conserved in other fungi. Fusion of these proteins to GFP and its variants has for the first time allowed the localization of these proteins in real time to the hyphal tip without the need for drastic fixation procedures. Such studies showed that vesicle-associated proteins localize to the Spitzenkörper and identified a second compartment located at the tip surface composed of exocyst and other proteins that mediate the fusion of secretory vesicles with the plasma membrane.
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Affiliation(s)
- Peter Sudbery
- Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield, UK.
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Harris SD. Hyphal morphogenesis: an evolutionary perspective. Fungal Biol 2011; 115:475-84. [PMID: 21640312 DOI: 10.1016/j.funbio.2011.02.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2010] [Revised: 01/31/2011] [Accepted: 02/02/2011] [Indexed: 12/20/2022]
Abstract
Two modes of cellular morphogenesis predominate within the fungal kingdom; yeast growth and hyphal growth. The availability of complete genome sequences that span the kingdom has made possible the use of comparative approaches that address important questions regarding the evolution of these growth modes. These comparisons have also emphasized the point that not all hyphae are the same despite outward appearances. Topics considered here include the origins of hyphal growth, as well as the potential causes of and the consequences resulting from the loss of hyphal growth in yeast lineages. The mechanisms that enable distinct morphological outputs (i.e., yeast vs. hyphae) using an essentially identical inventory of gene products are also considered. Finally, processes implicated in the regulation of hyphal tip complexes are addressed from an evolutionary perspective.
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Affiliation(s)
- Steven D Harris
- Center for Plant Science Innovation and Department of Plant Pathology, University of Nebraska, E126 Beadle Center, Lincoln, NE 68506, USA.
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Dou X, Wang Q, Qi Z, Song W, Wang W, Guo M, Zhang H, Zhang Z, Wang P, Zheng X. MoVam7, a conserved SNARE involved in vacuole assembly, is required for growth, endocytosis, ROS accumulation, and pathogenesis of Magnaporthe oryzae. PLoS One 2011; 6:e16439. [PMID: 21283626 PMCID: PMC3025985 DOI: 10.1371/journal.pone.0016439] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2010] [Accepted: 12/16/2010] [Indexed: 11/18/2022] Open
Abstract
Soluble NSF attachment protein receptor (SNARE) proteins play a central role in membrane fusion and vesicle transport of eukaryotic organisms including fungi. We previously identified MoSce22 as a homolog of Saccharomyces cerevisiae SNARE protein Sec22 to be involved in growth, stress resistance, and pathogenicity of Magnaporthe oryzae. Here, we provide evidences that MoVam7, an ortholog of S. cerevisiae SNARE protein Vam7, exerts conserved functions in vacuolar morphogenesis and functions in pathogenicity of M. oryzae. Staining with neutral red and FM4-64 revealed the presence of abnormal fragmented vacuoles and an absence of the Spitzenkörper body in the ΔMovam7 mutant. The ΔMovam7 mutant also exhibited reduced vegetative growth, poor conidiation, and failure to produce the infection structure appressorium. Additionally, treatments with cell wall perturbing agents indicated weakened cell walls and altered distributions of the cell wall component chitin. Furthermore, the ΔMovam7 mutant showed a reduced accumulation of reactive oxygen species (ROS) in the hyphal apex and failed to cause diseases on the rice plant. In summary, our studies indicate that MoVam7, like MoSec22, is a component of the SNARE complex whose functions in vacuole assembly also underlies the growth, conidiation, appressorium formation, and pathogenicity of M. oryzae. Further studies of MoVam7, MoSec22, and additional members of the SNARE complex are likely to reveal critical mechanisms in vacuole formation and membrane trafficking that is linked to fungal pathogenicity.
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Affiliation(s)
- Xianying Dou
- Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Agriculture, and Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Qi Wang
- Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Agriculture, and Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Zhongqiang Qi
- Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Agriculture, and Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Wenwen Song
- Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Agriculture, and Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Wei Wang
- Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Agriculture, and Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Min Guo
- Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Agriculture, and Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Haifeng Zhang
- Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Agriculture, and Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Zhengguang Zhang
- Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Agriculture, and Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
- * E-mail:
| | - Ping Wang
- Department of Pediatrics and Research Institute for Children, Louisiana State University Health Sciences Center, New Orleans, Louisiana, United States of America
| | - Xiaobo Zheng
- Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Agriculture, and Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
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Spitzenkorper, exocyst, and polarisome components in Candida albicans hyphae show different patterns of localization and have distinct dynamic properties. EUKARYOTIC CELL 2010; 9:1455-65. [PMID: 20693302 DOI: 10.1128/ec.00109-10] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
During the extreme polarized growth of fungal hyphae, secretory vesicles are thought to accumulate in a subapical region called the Spitzenkörper. The human fungal pathogen Candida albicans can grow in a budding yeast or hyphal form. When it grows as hyphae, Mlc1 accumulates in a subapical spot suggestive of a Spitzenkörper-like structure, while the polarisome components Spa2 and Bud6 localize to a surface crescent. Here we show that the vesicle-associated protein Sec4 also localizes to a spot, confirming that secretory vesicles accumulate in the putative C. albicans Spitzenkörper. In contrast, exocyst components localize to a surface crescent. Using a combination of fluorescence recovery after photobleaching (FRAP) and fluorescence loss in photobleaching (FLIP) experiments and cytochalasin A to disrupt actin cables, we showed that Spitzenkörper-located proteins are highly dynamic. In contrast, exocyst and polarisome components are stably located at the cell surface. It is thought that in Saccharomyces cerevisiae exocyst components are transported to the cell surface on secretory vesicles along actin cables. If each vesicle carried its own complement of exocyst components, then it would be expected that exocyst components would be as dynamic as Sec4 and would have the same pattern of localization. This is not what we observe in C. albicans. We propose a model in which a stream of vesicles arrives at the tip and accumulates in the Spitzenkörper before onward delivery to the plasma membrane mediated by exocyst and polarisome components that are more stable residents of the cell surface.
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Ambrosio LA, Hernández-Figueroa HE. Inversion of gradient forces for high refractive index particles in optical trapping. OPTICS EXPRESS 2010; 18:5802-5808. [PMID: 20389597 DOI: 10.1364/oe.18.005802] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The unexpected fact that a spherical dielectric particle with refractive index higher than the surrounding medium will not always be attracted towards high intensity regions of the trapping beam is fully demonstrated here using a simple ray optics approach. This unusual situation may happen due to the inversion of gradient forces, as shown here. Therefore, conventional schemes, such the one based on the use of two counter-propagating beams to cancel the scattering forces, will fail to trap the particle. However, effective trapping still can be obtained by adopting suitable incident laser beams.
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Affiliation(s)
- L A Ambrosio
- School of Electrical and Computer Engineering (FEEC),University of Campinas (Unicamp), Department of Microwave and Optics (DMO), 13083-970 - Campinas/SP, Brazil.
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Lewis MW, Robalino IV, Keyhani NO. Uptake of the fluorescent probe FM4-64 by hyphae and haemolymph-derived in vivo hyphal bodies of the entomopathogenic fungus Beauveria bassiana. Microbiology (Reading) 2009; 155:3110-3120. [DOI: 10.1099/mic.0.029165-0] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The entomopathogenic fungus Beauveria bassiana is under intensive study as a pest biological control agent. B. bassiana produces several distinct single-cell types that include aerial conidia, in vitro blastospores and submerged conidia. Under appropriate nutrient conditions these cells can elaborate germ tubes that form hyphae, which in turn lead to the formation of a fungal mycelium. In addition, B. bassiana displays a dimorphic transition, producing in vivo specific yeast-like hyphal bodies during growth in the arthropod haemolymph. The amphiphilic styryl dye FM4-64 was used to investigate internalization and morphological features of in vitro and in vivo insect haemolymph-derived B. bassiana cells. In vitro blastospores and submerged conidia displayed a punctate pattern of internal labelling, whereas aerial conidia failed to internalize the dye under the conditions tested. FM4-64 was also taken up into both apical and subapical compartments of living hyphae in a time-dependent manner, with clearly observable vesicle labelling. Internalization, where occurring, was reversibly disrupted by lowering the temperature of the assay or by treatment with azide/fluoride and latrunculin A. Treatment with cytochalasin D and monensin also caused abnormal vesicle trafficking, although some staining of vesicles was noted. Fungal cells derived from infected Heliothis virescens haemolymph (in vivo cells) actively internalized FM4-64. The in vivo blastospores or hyphal bodies displayed bright membrane and internal vesicle staining, although diffuse staining of internal structures was also visible. These results suggest active uptake by different developmental stages of B. bassiana, including haemolymph-derived cells that can evade the insect immune system.
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Affiliation(s)
- Michael W. Lewis
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL 32611, USA
| | - Ines V. Robalino
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL 32611, USA
| | - Nemat O. Keyhani
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL 32611, USA
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