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Neves-da-Rocha J, Santos-Saboya MJ, Lopes MER, Rossi A, Martinez-Rossi NM. Insights and Perspectives on the Role of Proteostasis and Heat Shock Proteins in Fungal Infections. Microorganisms 2023; 11:1878. [PMID: 37630438 PMCID: PMC10456932 DOI: 10.3390/microorganisms11081878] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 06/30/2023] [Accepted: 07/06/2023] [Indexed: 08/27/2023] Open
Abstract
Fungi are a diverse group of eukaryotic organisms that infect humans, animals, and plants. To successfully colonize their hosts, pathogenic fungi must continuously adapt to the host's unique environment, e.g., changes in temperature, pH, and nutrient availability. Appropriate protein folding, assembly, and degradation are essential for maintaining cellular homeostasis and survival under stressful conditions. Therefore, the regulation of proteostasis is crucial for fungal pathogenesis. The heat shock response (HSR) is one of the most important cellular mechanisms for maintaining proteostasis. It is activated by various stresses and regulates the activity of heat shock proteins (HSPs). As molecular chaperones, HSPs participate in the proteostatic network to control cellular protein levels by affecting their conformation, location, and degradation. In recent years, a growing body of evidence has highlighted the crucial yet understudied role of stress response circuits in fungal infections. This review explores the role of protein homeostasis and HSPs in fungal pathogenicity, including their contributions to virulence and host-pathogen interactions, as well as the concerted effects between HSPs and the main proteostasis circuits in the cell. Furthermore, we discuss perspectives in the field and the potential for targeting the components of these circuits to develop novel antifungal therapies.
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Affiliation(s)
- João Neves-da-Rocha
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto 14049-900, SP, Brazil; (M.J.S.-S.); (M.E.R.L.); (A.R.)
| | | | | | | | - Nilce M. Martinez-Rossi
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto 14049-900, SP, Brazil; (M.J.S.-S.); (M.E.R.L.); (A.R.)
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2
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Zhang S, Nie Y, Fan X, Wei W, Chen H, Xie X, Tang M. A transcriptional activator from Rhizophagus irregularis regulates phosphate uptake and homeostasis in AM symbiosis during phosphorous starvation. Front Microbiol 2023; 13:1114089. [PMID: 36741887 PMCID: PMC9895418 DOI: 10.3389/fmicb.2022.1114089] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Accepted: 12/28/2022] [Indexed: 01/22/2023] Open
Abstract
Introduction Phosphorus (P) is one of the most important nutrient elements for plant growth and development. Under P starvation, arbuscular mycorrhizal (AM) fungi can promote phosphate (Pi) uptake and homeostasis within host plants. However, the underlying mechanisms by which AM fungal symbiont regulates the AM symbiotic Pi acquisition from soil under P starvation are largely unknown. Here, we identify a HLH domain containing transcription factor RiPho4 from Rhizophagus irregularis. Methods To investigate the biological functions of the RiPho4, we combined the subcellular localization and Yeast One-Hybrid (Y1H) experiments in yeasts with gene expression and virus-induced gene silencing approach during AM symbiosis. Results The approach during AM symbiosis. The results indicated that RiPho4 encodes a conserved transcription factor among different fungi and is induced during the in planta phase. The transcription of RiPho4 is significantly up-regulated by P starvation. The subcellular localization analysis revealed that RiPho4 is located in the nuclei of yeast cells during P starvation. Moreover, knock-down of RiPho4 inhibits the arbuscule development and mycorrhizal Pi uptake under low Pi conditions. Importantly, RiPho4 can positively regulate the downstream components of the phosphate (PHO) pathway in R. irregularis. Discussion In summary, these new findings reveal that RiPho4 acts as a transcriptional activator in AM fungus to maintain arbuscule development and regulate Pi uptake and homeostasis in the AM symbiosis during Pi starvation.
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Affiliation(s)
| | | | | | | | | | - Xianan Xie
- *Correspondence: Xianan Xie, ; Ming Tang,
| | - Ming Tang
- *Correspondence: Xianan Xie, ; Ming Tang,
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3
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Muñoz-Guzmán F, Caballero V, Larrondo LF. A global search for novel transcription factors impacting the Neurospora crassa circadian clock. G3 (BETHESDA, MD.) 2021; 11:jkab100. [PMID: 33792687 PMCID: PMC8495738 DOI: 10.1093/g3journal/jkab100] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 03/16/2021] [Indexed: 01/15/2023]
Abstract
Eukaryotic circadian oscillators share a common circuit architecture, a negative feedback loop in which a positive element activates the transcription of a negative one that then represses the action of the former, inhibiting its own expression. While studies in mammals and insects have revealed additional transcriptional inputs modulating the expression of core clock components, this has been less characterized in the model Neurospora crassa, where the participation of other transcriptional components impacting circadian clock dynamics remains rather unexplored. Thus, we sought to identify additional transcriptional regulators modulating the N. crassa clock, following a reverse genetic screen based on luminescent circadian reporters and a collection of transcription factors (TFs) knockouts, successfully covering close to 60% of them. Besides the canonical core clock components WC-1 and -2, none of the tested transcriptional regulators proved to be essential for rhythmicity. Nevertheless, we identified a set of 23 TFs that when absent lead to discrete, but significant, changes in circadian period. While the current level of analysis does not provide mechanistic information about how these new players modulate circadian parameters, the results of this screen reveal that an important number of light and clock-regulated TFs, involved in a plethora of processes, are capable of modulating the clockworks. This partial reverse genetic clock screen also exemplifies how the N. crassa knockout collection continues to serve as an expedite platform to address broad biological questions.
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Affiliation(s)
- Felipe Muñoz-Guzmán
- ANID—Millennium Science Initiative Program—Millennium Institute for Integrative Biology (iBio), Santiago 8331150, Chile
- Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile
| | - Valeria Caballero
- Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile
| | - Luis F Larrondo
- ANID—Millennium Science Initiative Program—Millennium Institute for Integrative Biology (iBio), Santiago 8331150, Chile
- Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile
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4
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Wang T, Guan W, Du Y, Xu Y, He Z, Zhang Y, Kang C, Wan X, Chi X, Sun K, Zhang X. Proteome-wide analyses reveal diverse functions of acetylation proteins in Neurospora crassa. Proteomics 2021; 21:e2000212. [PMID: 33491270 DOI: 10.1002/pmic.202000212] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 12/15/2020] [Accepted: 01/12/2021] [Indexed: 11/07/2022]
Abstract
Quantitative acetyl-proteomics, a newly identified post-translational modification, is known to regulate transcriptional activity in different organisms. Neurospora crassa is a model ascomycete fungus maintained for biochemistry and molecular biology research; however, extensive studies of the functions of its acylation proteins have yet to be performed. In this study, using LC-MS/MS qualitative proteomics strategies, we identified 1909 modification sites on 940 proteins in N. crassa and analysed the functions of these proteins using GO enrichment, KEGG pathway, and subcellular location experiments. We classified the acetylation protein involvement in diverse pathways, and protein-protein interaction (PPI) network analysis further demonstrated that these proteins participate in diverse biological processes. In summary, our study comprehensively profiles the crosstalk of modified sites, and PPI among these proteins may form a complex network with both similar and distinct regulatory mechanisms, providing improved understanding of their biological functions in N. crassa.
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Affiliation(s)
- Tielin Wang
- State Key Laboratory Breeding Base of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, China
| | - Wei Guan
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yongxi Du
- State Key Laboratory Breeding Base of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, China
| | - Yang Xu
- State Key Laboratory Breeding Base of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, China
| | - Zhen He
- School of Horticulture and Plant Protection, Yangzhou University, Yangzhou, Jiangsu Province, P. R. China
| | - Yan Zhang
- State Key Laboratory Breeding Base of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, China
| | - Chuanzhi Kang
- State Key Laboratory Breeding Base of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, China
| | - Xiufu Wan
- State Key Laboratory Breeding Base of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, China
| | - Xiulian Chi
- State Key Laboratory Breeding Base of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, China
| | - Kai Sun
- State Key Laboratory Breeding Base of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, China
| | - Xiaobo Zhang
- State Key Laboratory Breeding Base of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, China
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5
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Martins MP, Martinez-Rossi NM, Sanches PR, Rossi A. The PAC-3 transcription factor critically regulates phenotype-associated genes in Neurospora crassa. Genet Mol Biol 2020; 43:e20190374. [PMID: 32584919 PMCID: PMC7355564 DOI: 10.1590/1678-4685-gmb-2019-0374] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 05/08/2020] [Indexed: 12/17/2022] Open
Abstract
Transcription factors play an important role in fungal environmental adaptive process by promoting adjustment to challenging stimuli via gene modulation and activation of signaling networks. The transcription factor encoded by the pac-3/rim101/pacC gene is involved in pH regulation and is associated with a wide variety of cellular functions. The deletion of pac-3 affects fungal development. In Neurospora crassa, the Δpac-3 strain presents diminished aerial growth and reduced conidiation. However, the PAC-3-regulated genes associated with this altered phenotype have not been elucidated. In this study, we used RNA-seq to analyze the phenotypic plasticity induced after pac-3 deletion in the filamentous fungus N. crassa cultivated in media supplemented with sufficient or limited inorganic phosphate. Genes related to morphology, hyphal development, and conidiation were of particular interest in this study. Our results suggest a pac-3 dependency in gene regulation in a Pi-dependent manner. Furthermore, our analysis suggested that the fungus attempts to overcome the deletion effects in a Δpac-3 mutant through a complex combined regulatory mechanism. Finally, the modulatory responses observed in the Δpac-3 strain, a double mutant generated based on the Δmus-52 mutant strain, is strain-specific, highlighting that the phenotypic impact may be attributed to pac-3 absence despite the combined mus-52 deletion.
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Affiliation(s)
- Maíra Pompeu Martins
- Universidade de São Paulo, Faculdade de Medicina de Ribeirão Preto, Departamento de Genética, Ribeirão Preto, SP, Brazil
| | - Nilce Maria Martinez-Rossi
- Universidade de São Paulo, Faculdade de Medicina de Ribeirão Preto, Departamento de Genética, Ribeirão Preto, SP, Brazil
| | - Pablo Rodrigo Sanches
- Universidade de São Paulo, Faculdade de Medicina de Ribeirão Preto, Departamento de Genética, Ribeirão Preto, SP, Brazil
| | - Antonio Rossi
- Universidade de São Paulo, Faculdade de Medicina de Ribeirão Preto, Departamento de Genética, Ribeirão Preto, SP, Brazil
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Peng Z, Tian J, Luo R, Kang Y, Lu Y, Hu Y, Liu N, Zhang J, Cheng H, Niu S, Zhang J, Yao Y. MiR399d and epigenetic modification comodulate anthocyanin accumulation in Malus leaves suffering from phosphorus deficiency. PLANT, CELL & ENVIRONMENT 2020; 43:1148-1159. [PMID: 31833568 DOI: 10.1111/pce.13697] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 11/17/2019] [Accepted: 12/03/2019] [Indexed: 05/14/2023]
Abstract
Inorganic phosphorus (Pi) deficiency induces anthocyanin accumulation in the leaves of some plant species; however, the molecular mechanisms underlying this phenomenon have not been well characterized. Here, we showed that microRNA399d (miR399d), high-affinity Pi transporter McPHT1;4, and McMYB10 are strongly induced in Malus leaves suffering from Pi deficiency. By culturing explants of transiently transformed plants in MS medium under conditions of Pi sufficiency and Pi deficiency, miR399d and McPHT1;4 were shown to play essential roles in the response to Pi deficiency and to play positive roles in the regulation of anthocyanin biosynthesis. Silencing of McHDA6 expression and treatment with the inhibitor trichostatin A suggested that the low expression of McHDA6 simultaneously reduced the transcription of McMET1 and decreased the methylation level of the McMYB10 promoter; however, the expression of McMYB10 and anthocyanin content were increased. Bimolecular fluorescence complementation and yeast two-hybrid assays revealed that McHDA6 binds directly to McMET1 through its BAH2 and DNMT1-RFD domains. Based on the results of our study, we propose a mechanism for the molecular regulation of anthocyanin biosynthesis, namely, the miR399d and epigenetic modification comodulation model, to explain the phenomenon in which leaves turn red under conditions of Pi deficiency.
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Affiliation(s)
- Zhen Peng
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing University of Agriculture, Beijing 102206, China
- College of Plant Science and Technology, Beijing University of Agriculture, Beijing 102206, China
- Beijing Key Laboratory for Agricultural Application and New Technique, Beijing University of Agriculture, Beijing 102206, China
| | - Ji Tian
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing University of Agriculture, Beijing 102206, China
- College of Plant Science and Technology, Beijing University of Agriculture, Beijing 102206, China
- Beijing Key Laboratory for Agricultural Application and New Technique, Beijing University of Agriculture, Beijing 102206, China
| | - Rongli Luo
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing University of Agriculture, Beijing 102206, China
- College of Plant Science and Technology, Beijing University of Agriculture, Beijing 102206, China
- Beijing Key Laboratory for Agricultural Application and New Technique, Beijing University of Agriculture, Beijing 102206, China
| | - Yanhui Kang
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing University of Agriculture, Beijing 102206, China
- College of Plant Science and Technology, Beijing University of Agriculture, Beijing 102206, China
- Beijing Key Laboratory for Agricultural Application and New Technique, Beijing University of Agriculture, Beijing 102206, China
| | - Yanfen Lu
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing University of Agriculture, Beijing 102206, China
- College of Plant Science and Technology, Beijing University of Agriculture, Beijing 102206, China
- Beijing Key Laboratory for Agricultural Application and New Technique, Beijing University of Agriculture, Beijing 102206, China
| | - Yujing Hu
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing University of Agriculture, Beijing 102206, China
- College of Plant Science and Technology, Beijing University of Agriculture, Beijing 102206, China
- Beijing Key Laboratory for Agricultural Application and New Technique, Beijing University of Agriculture, Beijing 102206, China
| | - Na Liu
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing University of Agriculture, Beijing 102206, China
- College of Plant Science and Technology, Beijing University of Agriculture, Beijing 102206, China
- Beijing Key Laboratory for Agricultural Application and New Technique, Beijing University of Agriculture, Beijing 102206, China
| | - Jie Zhang
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing University of Agriculture, Beijing 102206, China
- College of Plant Science and Technology, Beijing University of Agriculture, Beijing 102206, China
| | - Hao Cheng
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing University of Agriculture, Beijing 102206, China
- College of Plant Science and Technology, Beijing University of Agriculture, Beijing 102206, China
- Beijing Key Laboratory for Agricultural Application and New Technique, Beijing University of Agriculture, Beijing 102206, China
| | - Shuqing Niu
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing University of Agriculture, Beijing 102206, China
- College of Plant Science and Technology, Beijing University of Agriculture, Beijing 102206, China
- Beijing Key Laboratory for Agricultural Application and New Technique, Beijing University of Agriculture, Beijing 102206, China
| | - Jie Zhang
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing University of Agriculture, Beijing 102206, China
- College of Plant Science and Technology, Beijing University of Agriculture, Beijing 102206, China
- Beijing Key Laboratory for Agricultural Application and New Technique, Beijing University of Agriculture, Beijing 102206, China
| | - Yuncong Yao
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing University of Agriculture, Beijing 102206, China
- College of Plant Science and Technology, Beijing University of Agriculture, Beijing 102206, China
- Beijing Key Laboratory for Agricultural Application and New Technique, Beijing University of Agriculture, Beijing 102206, China
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7
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Horta MAC, Thieme N, Gao Y, Burnum-Johnson KE, Nicora CD, Gritsenko MA, Lipton MS, Mohanraj K, de Assis LJ, Lin L, Tian C, Braus GH, Borkovich KA, Schmoll M, Larrondo LF, Samal A, Goldman GH, Benz JP. Broad Substrate-Specific Phosphorylation Events Are Associated With the Initial Stage of Plant Cell Wall Recognition in Neurospora crassa. Front Microbiol 2019; 10:2317. [PMID: 31736884 PMCID: PMC6838226 DOI: 10.3389/fmicb.2019.02317] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 09/23/2019] [Indexed: 12/26/2022] Open
Abstract
Fungal plant cell wall degradation processes are governed by complex regulatory mechanisms, allowing the organisms to adapt their metabolic program with high specificity to the available substrates. While the uptake of representative plant cell wall mono- and disaccharides is known to induce specific transcriptional and translational responses, the processes related to early signal reception and transduction remain largely unknown. A fast and reversible way of signal transmission are post-translational protein modifications, such as phosphorylations, which could initiate rapid adaptations of the fungal metabolism to a new condition. To elucidate how changes in the initial substrate recognition phase of Neurospora crassa affect the global phosphorylation pattern, phospho-proteomics was performed after a short (2 min) induction period with several plant cell wall-related mono- and disaccharides. The MS/MS-based peptide analysis revealed large-scale substrate-specific protein phosphorylation and de-phosphorylations. Using the proteins identified by MS/MS, a protein-protein-interaction (PPI) network was constructed. The variance in phosphorylation of a large number of kinases, phosphatases and transcription factors indicate the participation of many known signaling pathways, including circadian responses, two-component regulatory systems, MAP kinases as well as the cAMP-dependent and heterotrimeric G-protein pathways. Adenylate cyclase, a key component of the cAMP pathway, was identified as a potential hub for carbon source-specific differential protein interactions. In addition, four phosphorylated F-Box proteins were identified, two of which, Fbx-19 and Fbx-22, were found to be involved in carbon catabolite repression responses. Overall, these results provide unprecedented and detailed insights into a so far less well known stage of the fungal response to environmental cues and allow to better elucidate the molecular mechanisms of sensory perception and signal transduction during plant cell wall degradation.
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Affiliation(s)
- Maria Augusta C. Horta
- Holzforschung München, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany
| | - Nils Thieme
- Holzforschung München, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany
| | - Yuqian Gao
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, United States
| | | | - Carrie D. Nicora
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, United States
| | - Marina A. Gritsenko
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, United States
| | - Mary S. Lipton
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA, United States
| | - Karthikeyan Mohanraj
- The Institute of Mathematical Sciences (IMSc), Homi Bhabha National Institute (HBNI), Chennai, India
| | - Leandro José de Assis
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Liangcai Lin
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
| | - Chaoguang Tian
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
| | - Gerhard H. Braus
- Department of Molecular Microbiology and Genetics, Institute of Microbiology and Genetics, Göttingen Center for Molecular Biosciences, University of Göttingen, Göttingen, Germany
| | - Katherine A. Borkovich
- Department of Microbiology & Plant Pathology, Institute for Integrative Genome Biology, University of California, Riverside, Riverside, CA, United States
| | - Monika Schmoll
- AIT - Austrian Institute of Technology GmbH, Center for Health & Bioresources, Tulln, Austria
| | - Luis F. Larrondo
- Millennium Institute for Integrative Biology (iBio), Departamento Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Areejit Samal
- The Institute of Mathematical Sciences (IMSc), Homi Bhabha National Institute (HBNI), Chennai, India
| | - Gustavo H. Goldman
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
- Institute for Advanced Study, Technical University of Munich, Garching, Germany
| | - J. Philipp Benz
- Holzforschung München, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany
- Institute for Advanced Study, Technical University of Munich, Garching, Germany
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8
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Martins MP, Martinez-Rossi NM, Sanches PR, Gomes EV, Bertolini MC, Pedersoli WR, Silva RN, Rossi A. The pH Signaling Transcription Factor PAC-3 Regulates Metabolic and Developmental Processes in Pathogenic Fungi. Front Microbiol 2019; 10:2076. [PMID: 31551996 PMCID: PMC6738131 DOI: 10.3389/fmicb.2019.02076] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 08/22/2019] [Indexed: 01/22/2023] Open
Abstract
The zinc finger transcription factor PAC-3/RIM101/PacC has a defined role in the secretion of enzymes and proteins in response to ambient pH, and also contributes to the virulence of species. Herein we evaluated the role of PAC-3 in the regulation of Neurospora crassa genes, in a model that examined the plant-fungi interactions. N. crassa is a model fungal species capable of exhibiting dynamic responses to its environment by employing endophytic or phytopathogenic behavior according to a given circumstance. Since plant growth and productivity are highly affected by pH and phosphorus (P) acquisition, we sought to verify the impact that induction of a Δpac-3 mutation would have under limited and sufficient Pi availability, while ensuring that the targeted physiological adjustments mimicked ambient pH and nutritional conditions required for efficient fungal growth and development. Our results suggest direct regulatory functions for PAC-3 in cell wall biosynthesis, homeostasis, oxidation-reduction processes, hydrolase activity, transmembrane transport, and modulation of genes associated with fungal virulence. Pi-dependent modulation was observed mainly in genes encoding for transporter proteins or related to cell wall development, thereby advancing the current understanding regarding colonization and adaptation processes in response to challenging environments. We have also provided comprehensive evidence that suggests a role for PAC-3 as a global regulator in plant pathogenic fungi, thus presenting results that have the potential to be applied to various types of microbes, with diverse survival mechanisms.
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Affiliation(s)
- Maíra Pompeu Martins
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Nilce M Martinez-Rossi
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Pablo R Sanches
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | | | - Maria Célia Bertolini
- Department of Biochemistry and Technological Chemistry, São Paulo State University, UNESP, Institute of Chemistry, Araraquara, Brazil
| | - Wellington R Pedersoli
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Roberto Nascimento Silva
- Department of Biochemistry and Immunology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Antonio Rossi
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
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9
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Lev S, Djordjevic JT. Why is a functional PHO pathway required by fungal pathogens to disseminate within a phosphate-rich host: A paradox explained by alkaline pH-simulated nutrient deprivation and expanded PHO pathway function. PLoS Pathog 2018; 14:e1007021. [PMID: 29928051 PMCID: PMC6013017 DOI: 10.1371/journal.ppat.1007021] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Affiliation(s)
- Sophie Lev
- Centre for Infectious Diseases and Microbiology, Westmead Institute for Medical Research, Westmead, Australia
- Sydney Medical School-Westmead, University of Sydney, Westmead, Australia
- Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, Australia
| | - Julianne Teresa Djordjevic
- Centre for Infectious Diseases and Microbiology, Westmead Institute for Medical Research, Westmead, Australia
- Sydney Medical School-Westmead, University of Sydney, Westmead, Australia
- Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, Australia
- * E-mail:
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10
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Martins MP, Gomes EV, Sanches PR, Pedersoli WR, Martinez-Rossi NM, Rossi A. mus-52 disruption and metabolic regulation in Neurospora crassa: Transcriptional responses to extracellular phosphate availability. PLoS One 2018; 13:e0195871. [PMID: 29668735 PMCID: PMC5905970 DOI: 10.1371/journal.pone.0195871] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Accepted: 03/30/2018] [Indexed: 12/01/2022] Open
Abstract
Advances in the understanding of molecular systems depend on specific tools like the disruption of genes to produce strains with the desired characteristics. The disruption of any mutagen sensitive (mus) genes in the model fungus Neurospora crassa, i.e. mus-51, mus-52, or mus-53, orthologous to the human genes KU70, KU80, and LIG4, respectively, provides efficient tools for gene targeting. Accordingly, we used RNA-sequencing and reverse transcription-quantitative polymerase chain reaction amplification techniques to evaluate the effects of mus-52 deletion in N. crassa gene transcriptional modulation, and thus, infer its influence regarding metabolic response to extracellular availability of inorganic phosphate (Pi). Notably, the absence of MUS-52 affected the transcription of a vast number of genes, highlighting the expression of those coding for transcription factors, kinases, circadian clocks, oxi-reduction balance, and membrane- and nucleolus-related proteins. These findings may provide insights toward the KU molecular mechanisms, which have been related to telomere maintenance, apoptosis, DNA replication, and gene transcription regulation, as well as associated human conditions including immune system disorders, cancer, and aging.
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Affiliation(s)
- Maíra P. Martins
- Department of Genetics, Ribeirão Preto Medical School, São Paulo University, Ribeirão Preto, São Paulo, Brazil
| | - Eriston V. Gomes
- Department of Genetics, Ribeirão Preto Medical School, São Paulo University, Ribeirão Preto, São Paulo, Brazil
| | - Pablo R. Sanches
- Department of Genetics, Ribeirão Preto Medical School, São Paulo University, Ribeirão Preto, São Paulo, Brazil
| | - Wellington R. Pedersoli
- Department of Genetics, Ribeirão Preto Medical School, São Paulo University, Ribeirão Preto, São Paulo, Brazil
| | - Nilce M. Martinez-Rossi
- Department of Genetics, Ribeirão Preto Medical School, São Paulo University, Ribeirão Preto, São Paulo, Brazil
| | - Antonio Rossi
- Department of Genetics, Ribeirão Preto Medical School, São Paulo University, Ribeirão Preto, São Paulo, Brazil
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11
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Kamei M, Yamashita K, Takahashi M, Fukumori F, Ichiishi A, Fujimura M. Involvement of MAK-1 and MAK-2 MAP kinases in cell wall integrity in Neurospora crassa. Biosci Biotechnol Biochem 2016; 80:1843-52. [DOI: 10.1080/09168451.2016.1189321] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Abstract
Among three MAPK disruptants of Neurospora crassa, Δmak-1 was sensitive and Δmak-2 was hypersensitive to micafungin, a beta-1,3-glucan synthase inhibitor, than the wild-type or Δos-2 strains. We identified six micafungin-inducible genes that are involved in cell wall integrity (CWI) and found that MAK-1 regulated the transcription of non-anchored cell wall protein gene, ncw-1, and the beta-1,3-endoglucanase gene, bgt-2, whereas MAK-2 controlled the expression of the glycosylhydrolase-like protein gene, gh76-5, and the C4-dicarboxylate transporter gene, tdt-1. Western blotting analysis revealed that, in the wild-type strain, MAK-1 was constitutively phosphorylated from conidial germination to hyphal development. In contrast, the phosphorylation of MAK-2 was growth phase-dependent, and micafungin induced the phosphorylation of unphosphorylated MAK-2. It should be noted that the phosphorylation of MAK-1 was virtually abolished in the Δmak-2 strain, but was significantly induced by micafungin, suggesting functional cross talk between MAK-1 and MAK-2 signalling pathway in CWI.
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Affiliation(s)
- Masayuki Kamei
- Faculty of Life Sciences, Toyo University, Oura-gun, Japan
- Department of Microbiology, University of Georgia, Athens, GA, USA
| | | | | | - Fumiyasu Fukumori
- Faculty of Food and Nutritional Sciences, Toyo University, Oura-gun, Japan
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12
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Martinez-Rossi NM, Jacob TR, Sanches PR, Peres NTA, Lang EAS, Martins MP, Rossi A. Heat Shock Proteins in Dermatophytes: Current Advances and Perspectives. Curr Genomics 2016; 17:99-111. [PMID: 27226766 PMCID: PMC4864838 DOI: 10.2174/1389202917666151116212437] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2015] [Revised: 07/02/2015] [Accepted: 07/13/2015] [Indexed: 11/29/2022] Open
Abstract
Heat shock proteins (HSPs) are proteins whose transcription responds rapidly to temperature shifts. They constitute a family of molecular chaperones, involved in the proper folding and stabilisation of proteins under physiological and adverse conditions. HSPs also assist in the protection and recovery of cells exposed to a variety of stressful conditions, including heat. The role of HSPs extends beyond chaperoning proteins, as they also participate in diverse cellular functions, such as the assembly of macromolecular complexes, protein transport and sorting, dissociation of denatured protein aggregates, cell cycle control, and programmed cell death. They are also important antigens from a variety of pathogens, are able to stimulate innate immune cells, and are implicated in acquired immunity. In fungi, HSPs have been implicated in virulence, dimorphic transition, and drug resistance. Some HSPs are potential targets for therapeutic strategies. In this review, we discuss the current understanding of HSPs in dermatophytes, which are a group of keratinophilic fungi responsible for superficial mycoses in humans and animals. Computational analyses were performed to characterise the group of proteins in these dermatophytes, as well as to assess their conservation and to identify DNA-binding domains (5′-nGAAn-3′) in the promoter regions of the hsp genes. In addition, the quantification of the transcript levels of few genes in a pacC background helped in the development of an extended model for the regulation of the expression of the hsp genes, which supports the participation of the pH-responsive transcriptional regulator PacC in this process.
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Affiliation(s)
- Nilce M Martinez-Rossi
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Tiago R Jacob
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Pablo R Sanches
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Nalu T A Peres
- Present address: Department of Morphology, Federal University of Sergipe, SE, Brazil
| | - Elza A S Lang
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Maíra P Martins
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Antonio Rossi
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP, Brazil
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13
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Abstract
PTH and Vitamin D are two major regulators of mineral metabolism. They play critical roles in the maintenance of calcium and phosphate homeostasis as well as the development and maintenance of bone health. PTH and Vitamin D form a tightly controlled feedback cycle, PTH being a major stimulator of vitamin D synthesis in the kidney while vitamin D exerts negative feedback on PTH secretion. The major function of PTH and major physiologic regulator is circulating ionized calcium. The effects of PTH on gut, kidney, and bone serve to maintain serum calcium within a tight range. PTH has a reciprocal effect on phosphate metabolism. In contrast, vitamin D has a stimulatory effect on both calcium and phosphate homeostasis, playing a key role in providing adequate mineral for normal bone formation. Both hormones act in concert with the more recently discovered FGF23 and klotho, hormones involved predominantly in phosphate metabolism, which also participate in this closely knit feedback circuit. Of great interest are recent studies demonstrating effects of both PTH and vitamin D on the cardiovascular system. Hyperparathyroidism and vitamin D deficiency have been implicated in a variety of cardiovascular disorders including hypertension, atherosclerosis, vascular calcification, and kidney failure. Both hormones have direct effects on the endothelium, heart, and other vascular structures. How these effects of PTH and vitamin D interface with the regulation of bone formation are the subject of intense investigation.
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Affiliation(s)
- Syed Jalal Khundmiri
- Department of Medicine, University of Louisville, Louisville, Kentucky, USA
- Department of Physiology and Biophysics, University of Louisville, Louisville, Kentucky, USA
| | - Rebecca D. Murray
- Department of Medicine, University of Louisville, Louisville, Kentucky, USA
- Department of Physiology and Biophysics, University of Louisville, Louisville, Kentucky, USA
| | - Eleanor Lederer
- Department of Medicine, University of Louisville, Louisville, Kentucky, USA
- Department of Physiology and Biophysics, University of Louisville, Louisville, Kentucky, USA
- Robley Rex VA Medical Center, University of Louisville, Louisville, Kentucky, USA
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14
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Mendes NS, Silva PM, Silva-Rocha R, Martinez-Rossi NM, Rossi A. Pre-mRNA splicing is modulated by antifungal drugs in the filamentous fungus Neurospora crassa. FEBS Open Bio 2016; 6:358-68. [PMID: 27239448 PMCID: PMC4821360 DOI: 10.1002/2211-5463.12047] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2015] [Revised: 02/10/2016] [Accepted: 02/15/2016] [Indexed: 11/17/2022] Open
Abstract
For this study, we sought to identify pre‐mRNA processing events modulated by changes in extracellular pH, inorganic phosphate, and antifungal drugs. We examined genes with at least four putative introns whose transcriptional level responded to these effectors. We showed that the intron retention levels of genes encoding asparagine synthetase 2, C6‐zinc finger regulator (fluffy), and a farnesyltransferase respond to amphotericin B, ketoconazole, and other effectors. In general, the assayed antifungals promoted the disruption of the structural domains of these proteins probably leading to their inactivation, which emphasize the complexity of the metabolic modulation exerted by antifungal signaling.
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Affiliation(s)
- Niege S Mendes
- Department of Genetics Ribeirão Preto Medical School University of São Paulo Ribeirão Preto SP Brazil
| | - Patricia M Silva
- Department of Genetics Ribeirão Preto Medical School University of São Paulo Ribeirão Preto SP Brazil
| | - Rafael Silva-Rocha
- Department of Molecular and Cellular Biology Ribeirão Preto Medical School University of São Paulo Ribeirão Preto SP Brazil
| | - Nilce M Martinez-Rossi
- Department of Genetics Ribeirão Preto Medical School University of São Paulo Ribeirão Preto SP Brazil
| | - Antonio Rossi
- Department of Genetics Ribeirão Preto Medical School University of São Paulo Ribeirão Preto SP Brazil
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15
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16
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Deng S, Wang CY, Zhang X, Wang Q, Lin L. VdNUC-2, the Key Regulator of Phosphate Responsive Signaling Pathway, Is Required for Verticillium dahliae Infection. PLoS One 2015; 10:e0145190. [PMID: 26670613 PMCID: PMC4682923 DOI: 10.1371/journal.pone.0145190] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Accepted: 12/01/2015] [Indexed: 02/07/2023] Open
Abstract
In fungal cells, a phosphate (Pi) responsive signaling and metabolism (PHO) pathway regulates Pi-homeostasis. NUC-2/PHO81 and its homologs are one of the most important components in the regulation pathway. In soil-borne phytopathogenic fungus Verticillium dahliae, we identified a Neurospora crassa nuc-2 homolog gene VdNUC-2. VdNUC-2 is composed of 1,018 amino acids, and is highly conserved in tested filamentous fungi. Under conditions of Pi-starvation, compared with the wild-type strain and ectopic complementation strains, the VdNUC-2 knocked out mutants exhibited reduced radial growth, decreased production of conidia and microsclerotia, and were more sensitive to hydrogen peroxide stress. The virulence of VdNUC-2 defective mutants was significantly compromised, and that was unable to be restored by exogenous application of extra Pi. Additionally, the deletion mutants of VdNUC-1, a key transcription factor gene positively controlled by VdNUC-2 in the PHO pathway, showed the similar cultural phenotypes as VdNUC-2 mutants when both of them grew in Pi-limited conditions. However, the virulence of VdNUC-1 mutants was comparable to the wild-type strain. These evidences indicated that the virulence reduction in VdNUC-2 mutants is not due to the interruptions in the PHO pathway or the disturbance of Pi-homeostasis in V. dahliae cytoplasm. VdNUC-2 is not only a crucial gene in the PHO pathway in V. dahliae, but also is required for the full virulence during host-infection.
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Affiliation(s)
- Sheng Deng
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Cai-yue Wang
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Xin Zhang
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Qing Wang
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Ling Lin
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, China
- * E-mail:
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17
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Abstract
In budding yeast, Saccharomyces cerevisiae, the phosphate signalling and response pathway, known as PHO pathway, monitors phosphate cytoplasmic levels by controlling genes involved in scavenging, uptake and utilization of phosphate. Recent attempts to understand the phosphate starvation response in other ascomycetes have suggested the existence of both common and novel components of the budding yeast PHO pathway in these ascomycetes. In this review, we discuss the components of PHO pathway, their roles in maintaining phosphate homeostasis in yeast and their conservation across ascomycetes. The role of high-affinity transporter, Pho84, in sensing and signalling of phosphate has also been discussed.
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Affiliation(s)
- Parul Tomar
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai 400 005, India
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18
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Defects in phosphate acquisition and storage influence virulence of Cryptococcus neoformans. Infect Immun 2014; 82:2697-712. [PMID: 24711572 DOI: 10.1128/iai.01607-14] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Nutrient acquisition and sensing are critical aspects of microbial pathogenesis. Previous transcriptional profiling indicated that the fungal pathogen Cryptococcus neoformans, which causes meningoencephalitis in immunocompromised individuals, encounters phosphate limitation during proliferation in phagocytic cells. We therefore tested the hypothesis that phosphate acquisition and polyphosphate metabolism are important for cryptococcal virulence. Deletion of the high-affinity uptake system interfered with growth on low-phosphate medium, perturbed the formation of virulence factors (capsule and melanin), reduced survival in macrophages, and attenuated virulence in a mouse model of cryptococcosis. Additionally, analysis of nutrient sensing functions for C. neoformans revealed regulatory connections between phosphate acquisition and storage and the iron regulator Cir1, cyclic AMP (cAMP)-dependent protein kinase A (PKA), and the calcium-calmodulin-activated protein phosphatase calcineurin. Deletion of the VTC4 gene encoding a polyphosphate polymerase blocked the ability of C. neoformans to produce polyphosphate. The vtc4 mutant behaved like the wild-type strain in interactions with macrophages and in the mouse infection model. However, the fungal load in the lungs was significantly increased in mice infected with vtc4 deletion mutants. In addition, the mutant was impaired in the ability to trigger blood coagulation in vitro, a trait associated with polyphosphate. Overall, this study reveals that phosphate uptake in C. neoformans is critical for virulence and that its regulation is integrated with key signaling pathways for nutrient sensing.
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Dick CF, Dos-Santos ALA, Meyer-Fernandes JR. Inorganic phosphate uptake in unicellular eukaryotes. Biochim Biophys Acta Gen Subj 2014; 1840:2123-7. [PMID: 24674820 DOI: 10.1016/j.bbagen.2014.03.014] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Revised: 02/27/2014] [Accepted: 03/17/2014] [Indexed: 11/18/2022]
Abstract
BACKGROUND Inorganic phosphate (Pi) is an essential nutrient for all organisms. The route of Pi utilization begins with Pi transport across the plasma membrane. SCOPE OF REVIEW Here, we analyzed the gene sequences and compared the biochemical profiles, including kinetic and modulator parameters, of Pi transporters in unicellular eukaryotes. The objective of this review is to evaluate the recent findings regarding Pi uptake mechanisms in microorganisms, such as the fungi Neurospora crassa and Saccharomyces cerevisiae and the parasite protozoans Trypanosoma cruzi, Trypanosoma rangeli, Leishmania infantum and Plasmodium falciparum. MAJOR CONCLUSION Pi uptake is the key step of Pi homeostasis and in the subsequent signaling event in eukaryotic microorganisms. GENERAL SIGNIFICANCE Biochemical and structural studies are important for clarifying mechanisms of Pi homeostasis, as well as Pi sensor and downstream pathways, and raise possibilities for future studies in this field.
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Affiliation(s)
- Claudia F Dick
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD, USA.
| | - André L A Dos-Santos
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD, USA
| | - José R Meyer-Fernandes
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil; Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagem, Rio de Janeiro, RJ, Brazil.
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20
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Rossi A, Cruz AHS, Santos RS, Silva PM, Silva EM, Mendes NS, Martinez-Rossi NM. Ambient pH sensing in filamentous fungi: pitfalls in elucidating regulatory hierarchical signaling networks. IUBMB Life 2013; 65:930-5. [PMID: 24265200 DOI: 10.1002/iub.1217] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2013] [Accepted: 09/25/2013] [Indexed: 11/12/2022]
Abstract
In this article, the experiments used to construct the ambient pH-signaling network involved in the secretion of enzymes by filamentous fungi have been reviewed, focusing on the phosphate-repressible phosphatases in Aspergillus nidulans. Classic and molecular genetics have been used to demonstrate that proteolysis of the transcription factor PacC at alkaline ambient pH is imperative for its action, implying that the full-length version is not an active molecular form of PacC. It has been hypothesized that the transcriptional regulator PacC may be functional at both acidic and alkaline ambient pH, in either the full-length or the proteolyzed form, if it carries a pal-dependent molecular tag. The products of the pal genes are involved in a metabolic pathway that led to the synthesis of effector molecules that tag the pacC product, perhaps facilitating its proteolysis.
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Affiliation(s)
- Antonio Rossi
- Department of Biochemistry and Immunology, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
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