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Dai M, Du W, Lu L, Zhang S. Transcription factors SltA and CrzA reversely regulate calcium homeostasis under calcium-limited conditions. Appl Environ Microbiol 2023; 89:e0117023. [PMID: 37874299 PMCID: PMC10686095 DOI: 10.1128/aem.01170-23] [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: 07/11/2023] [Accepted: 09/11/2023] [Indexed: 10/25/2023] Open
Abstract
IMPORTANCE Calcium ions are ubiquitous intracellular signaling molecules for many signaling pathways regulating the fungal response to stress and antifungal drugs. The concentration of intracellular calcium is tightly regulated in its storage, release, and distribution. CrzA is the best-studied transcription factor that regulates this process under sufficient calcium or other external signals. However, CrzA was excluded from nuclei and then lost transcriptional activation under calcium-limited conditions. The regulators in the Ca2+ signaling pathway under calcium-limited conditions remain unclear. Here, we identified SltA as a key regulator in the Ca2+ signaling pathway under calcium-limited conditions, and the underlying mechanisms were further explored in Aspergillus fumigatus. These findings reveal a transcriptional control pathway that precisely regulates calcium homeostasis under calcium-limited conditions.
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Affiliation(s)
- Mengyao Dai
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Engineering and Technology Research Center for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing, Jiangsu, China
| | - Wenlong Du
- Department of Bioinformatics, School of Life Sciences, Xuzhou Medical University, Xuzhou, Jiangsu, China
| | - Ling Lu
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Engineering and Technology Research Center for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing, Jiangsu, China
| | - Shizhu Zhang
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Engineering and Technology Research Center for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing, Jiangsu, China
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Li Y, Dai M, Lu L, Zhang Y. The C 2H 2-Type Transcription Factor ZfpA, Coordinately with CrzA, Affects Azole Susceptibility by Regulating the Multidrug Transporter Gene atrF in Aspergillus fumigatus. Microbiol Spectr 2023; 11:e0032523. [PMID: 37318356 PMCID: PMC10434176 DOI: 10.1128/spectrum.00325-23] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 05/26/2023] [Indexed: 06/16/2023] Open
Abstract
The incidence of invasive aspergillosis caused by Aspergillus fumigatus has risen steadily over the past few decades due to the limited effective treatment options and the emergence of antifungal-resistant isolates. In clinic-isolated A. fumigatus, the azole resistance mechanism is primarily caused by mutations of the drug target and/or overexpression of drug efflux pumps. However, knowledge about how drug efflux pumps are transcriptionally regulated is limited. In this study, we found that loss of a C2H2 transcription factor ZfpA (zinc finger protein) results in the marked upregulation of a series of drug efflux pump-encoding genes, especially atrF, which contributes to azole drug resistance in A. fumigatus. CrzA is a previously identified positive transcription factor for genes of drug efflux pumps, and ZfpA transcriptionally inhibits expressions of drug efflux pumps in a CrzA-dependent way. Under the treatment of azoles, both ZfpA and CrzA transfer to nuclei and coregulate the expression of multidrug transporters and then keep normal drug susceptibility in fungal cells. Findings in this study demonstrated that ZfpA is not only involved in fungal growth and virulence potential but also negatively regulates antifungal drug susceptibility. IMPORTANCE Conserved across all kingdoms of life, ABC transporters comprise one of the largest protein families. They are associated with multidrug resistance, affecting aspects such as resistance to antimicrobials or anticancer drugs. Despite the importance of ABC transporters in multidrug resistance, the understanding of their regulatory network is still limited in A. fumigatus. Here, we found that the loss of the transcription factor ZfpA induces the expression of the ABC transporter gene atrF, altering azole susceptibility in A. fumigatus. ZfpA, coordinately with CrzA, affects the azole susceptibility by regulating the expression of the ABC transporter gene atrF. These findings reveal the regulatory mechanism of the ABC transporter gene atrF in A. fumigatus.
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Affiliation(s)
- Yeqi Li
- 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
| | - 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
| | - 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
| | - Yuanwei 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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Martín JF. Interaction of calcium responsive proteins and transcriptional factors with the PHO regulon in yeasts and fungi. Front Cell Dev Biol 2023; 11:1225774. [PMID: 37601111 PMCID: PMC10437122 DOI: 10.3389/fcell.2023.1225774] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Accepted: 07/24/2023] [Indexed: 08/22/2023] Open
Abstract
Phosphate and calcium ions are nutrients that play key roles in growth, differentiation and the production of bioactive secondary metabolites in filamentous fungi. Phosphate concentration regulates the biosynthesis of hundreds of fungal metabolites. The central mechanisms of phosphate transport and regulation, mediated by the master Pho4 transcriptional factor are known, but many aspects of the control of gene expression need further research. High ATP concentration in the cells leads to inositol pyrophosphate molecules formation, such as IP3 and IP7, that act as phosphorylation status reporters. Calcium ions are intracellular messengers in eukaryotic organisms and calcium homeostasis follows elaborated patterns in response to different nutritional and environmental factors, including cross-talking with phosphate concentrations. A large part of the intracellular calcium is stored in vacuoles and other organelles forming complexes with polyphosphate. The free cytosolic calcium concentration is maintained by transport from the external medium or by release from the store organelles through calcium permeable transient receptor potential (TRP) ion channels. Calcium ions, particularly the free cytosolic calcium levels, control the biosynthesis of fungal metabolites by two mechanisms, 1) direct interaction of calcium-bound calmodulin with antibiotic synthesizing enzymes, and 2) by the calmodulin-calcineurin signaling cascade. Control of very different secondary metabolites, including pathogenicity determinants, are mediated by calcium through the Crz1 factor. Several interactions between calcium homeostasis and phosphate have been demonstrated in the last decade: 1) The inositol pyrophosphate IP3 triggers the release of calcium ions from internal stores into the cytosol, 2) Expression of the high affinity phosphate transporter Pho89, a Na+/phosphate symporter, is controlled by Crz1. Also, mutants defective in the calcium permeable TRPCa7-like of Saccharomyces cerevisiae shown impaired expression of Pho89. This information suggests that CrzA and Pho89 play key roles in the interaction of phosphate and calcium regulatory pathways, 3) Finally, acidocalcisomes organelles have been found in mycorrhiza and in some melanin producing fungi that show similar characteristics as protozoa calcisomes. In these organelles there is a close interaction between orthophosphate, pyrophosphate and polyphosphate and calcium ions that are absorbed in the polyanionic polyphosphate matrix. These advances open new perspectives for the control of fungal metabolism.
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Affiliation(s)
- Juan F. Martín
- Departamento de Biología Molecular, Área de Microbiología, Universidad de León, León, Spain
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Gupta S, Kumar A, Tamuli R. CRZ1 transcription factor is involved in cell survival, stress tolerance, and virulence in fungi. J Biosci 2022. [DOI: 10.1007/s12038-022-00294-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Ancuceanu R, Hovaneț MV, Cojocaru-Toma M, Anghel AI, Dinu M. Potential Antifungal Targets for Aspergillus sp. from the Calcineurin and Heat Shock Protein Pathways. Int J Mol Sci 2022; 23:ijms232012543. [PMID: 36293395 PMCID: PMC9603945 DOI: 10.3390/ijms232012543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 10/13/2022] [Accepted: 10/15/2022] [Indexed: 11/16/2022] Open
Abstract
Aspergillus species, especially A. fumigatus, and to a lesser extent others (A. flavus, A. niger, A. terreus), although rarely pathogenic to healthy humans, can be very aggressive to immunocompromised patients (they are opportunistic pathogens). Although survival rates for such infections have improved in recent decades following the introduction of azole derivatives, they remain a clinical challenge. The fact that current antifungals act as fungistatic rather than fungicide, that they have limited safety, and that resistance is becoming increasingly common make the need for new, more effective, and safer therapies to become more acute. Over the last decades, knowledge about the molecular biology of A. fumigatus and other Aspergillus species, and particularly of calcineurin, Hsp90, and their signaling pathway proteins, has progressed remarkably. Although calcineurin has attracted much interest, its adverse effects, particularly its immunosuppressive effects, make it less attractive than it might at first appear. The situation is not very different for Hsp90. Other proteins from their signaling pathways, such as protein kinases phosphorylating the four SPRR serine residues, CrzA, rcnA, pmcA-pmcC (particularly pmcC), rfeF, BAR adapter protein(s), the phkB histidine kinase, sskB MAP kinase kinase, zfpA, htfA, ctfA, SwoH (nucleoside diphosphate kinase), CchA, MidA, FKBP12, the K27 lysine position from Hsp90, PkcA, MpkA, RlmA, brlA, abaA, wetA, other heat shock proteins (Hsp70, Hsp40, Hsp12) currently appear promising and deserve further investigation as potential targets for antifungal drug development.
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Affiliation(s)
- Robert Ancuceanu
- Faculty of Pharmacy, Carol Davila University of Medicine and Pharmacy, 020956 Bucharest, Romania
- Correspondence: (R.A.); (M.V.H.)
| | - Marilena Viorica Hovaneț
- Faculty of Pharmacy, Carol Davila University of Medicine and Pharmacy, 020956 Bucharest, Romania
- Correspondence: (R.A.); (M.V.H.)
| | - Maria Cojocaru-Toma
- Faculty of Pharmacy, Nicolae Testemițanu State University of Medicine and Pharmacy, 2025 Chisinau, Moldova
| | - Adriana-Iuliana Anghel
- Faculty of Pharmacy, Carol Davila University of Medicine and Pharmacy, 020956 Bucharest, Romania
| | - Mihaela Dinu
- Faculty of Pharmacy, Carol Davila University of Medicine and Pharmacy, 020956 Bucharest, Romania
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Zhao K, Liu Z, Li M, Hu Y, Yang L, Song X, Qin Y. Drafting Penicillium oxalicum calcineurin-CrzA pathway by combining the analysis of phenotype, transcriptome, and endogenous protein-protein interactions. Fungal Genet Biol 2021; 158:103652. [PMID: 34920105 DOI: 10.1016/j.fgb.2021.103652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 11/17/2021] [Accepted: 12/08/2021] [Indexed: 11/04/2022]
Abstract
Fungi sense environmental signals and coordinate growth, development, and metabolism accordingly. Calcium-calmodulin-calcineurin signaling is a conserved cascade pathway in fungi. One of the most important downstream targets of this pathway is the transcription factor Crz1/CrzA, which plays an essential role in various cellular processes. The putative collaborators of Penicillium oxalicum CrzA (PoCrzA) were found, through tandem affinity purification followed by mass spectrometric analysis (TAP-MS). A total of 50 protein-protein interaction collaborators of PoCrzA were observed. Among them, some collaborators, such as the catalytic subunit of calcineurin (Cna1, calcineurin A), the regulatory catalytic subunit of calcineurin (Cnb1, calcineurin B), and a 14-3-3 protein Bmh1, which were previously reported in yeast, were identified. Some putative collaborators, including two karyopherins (exportin Los1 and importin Srp1), two kinases (Fus3 and Slt2p), and a general transcriptional corepressor (Cyc8), were also found. The CrzA deletion mutant ΔPocrzA exhibited slow hyphal growth, impaired conidiogenesis, and reduced extracellular cellulase synthesis. Phenotype and transcriptome analysis showed that PoCrzA regulated fungal development in a Flbs-BrlA-dependent manner and participated in cellulase synthesis by modulating cellulolytic gene expression. On the basis of the results of TAP-MS, transcriptome, and phenotypic analysis in P. oxalicum, our study was the first to draft the calcineurin-CrzA pathway in cellulolytic fungi.
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Affiliation(s)
- Kaili Zhao
- National Glycoengineering Research Center, Shandong University, No. 72 Binhai Road, Qingdao 266237, China.
| | - Zhongjiao Liu
- National Glycoengineering Research Center, Shandong University, No. 72 Binhai Road, Qingdao 266237, China.
| | - Mengxue Li
- National Glycoengineering Research Center, Shandong University, No. 72 Binhai Road, Qingdao 266237, China.
| | - Yueyan Hu
- National Glycoengineering Research Center, Shandong University, No. 72 Binhai Road, Qingdao 266237, China; State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, No. 72 Binhai Road, Qingdao 266237, China.
| | - Ling Yang
- Vocational Education College, Dezhou University, Dezhou 253023, China.
| | - Xin Song
- National Glycoengineering Research Center, Shandong University, No. 72 Binhai Road, Qingdao 266237, China; State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, No. 72 Binhai Road, Qingdao 266237, China.
| | - Yuqi Qin
- National Glycoengineering Research Center, Shandong University, No. 72 Binhai Road, Qingdao 266237, China; State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, No. 72 Binhai Road, Qingdao 266237, China.
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Valero C, Colabardini AC, de Castro PA, Silva LP, Ries LNA, Pardeshi L, Wang F, Rocha MC, Malavazi I, Silva RN, Martins C, Domingos P, Pereira-Silva C, Bromley MJ, Wong KH, Goldman GH. Aspergillus Fumigatus ZnfA, a Novel Zinc Finger Transcription Factor Involved in Calcium Metabolism and Caspofungin Tolerance. FRONTIERS IN FUNGAL BIOLOGY 2021; 2:689900. [PMID: 37744107 PMCID: PMC10512341 DOI: 10.3389/ffunb.2021.689900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 07/16/2021] [Indexed: 09/26/2023]
Abstract
Invasive pulmonary aspergillosis is a life-threatening fungal infection especially in the immunocompromised patients. The low diversity of available antifungal drugs coupled with the emergence of antifungal resistance has become a worldwide clinical concern. The echinocandin Caspofungin (CSP) is recommended as a second-line therapy but resistance and tolerance mechanisms have been reported. However, how the fungal cell articulates the response to CSP is not completely understood. This work provides a detailed characterization of ZnfA, a transcription factor (TF) identified in previous screening studies that is involved in the A. fumigatus responses to calcium and CSP. This TF plays an important role in the regulation of iron homeostasis and cell wall organization in response to high CSP concentrations as revealed by Chromatin Immunoprecipitation coupled to DNA sequencing (ChIP-seq) analysis. Furthermore, ZnfA acts collaboratively with the key TF CrzA in modulating the response to calcium as well as cell wall and osmotic stresses. This study therefore describes the existence of an additional, previously unknown TF that bridges calcium signaling and the CSP cellular response and further exposes the complex connections that exist among different pathways which govern stress sensing and signaling in A. fumigatus.
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Affiliation(s)
- Clara Valero
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Ana Cristina Colabardini
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Patrícia Alves de Castro
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Lilian Pereira Silva
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | | | - Lakhansing Pardeshi
- Faculty of Health Sciences, University of Macau, Macau, China
- Genomics and Bioinformatics Core, Faculty of Health Sciences, University of Macau, Macau, China
| | - Fang Wang
- Faculty of Health Sciences, University of Macau, Macau, China
- Genomics and Bioinformatics Core, Faculty of Health Sciences, University of Macau, Macau, China
| | - Marina Campos Rocha
- Departamento de Genética e Evolução, Centro de Ciências Biológicas e da Saúde, Universidade Federal de São Carlos, São Paulo, Brazil
| | - Iran Malavazi
- Departamento de Genética e Evolução, Centro de Ciências Biológicas e da Saúde, Universidade Federal de São Carlos, São Paulo, Brazil
| | | | - Celso Martins
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa (ITQB NOVA), Oeiras, Portugal
| | - Patrícia Domingos
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa (ITQB NOVA), Oeiras, Portugal
| | - Cristina Pereira-Silva
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa (ITQB NOVA), Oeiras, Portugal
| | - Michael J. Bromley
- Manchester Fungal Infection Group, Core Technology Facility, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, The University of Manchester, Manchester, United Kingdom
- Manchester Academic Health Science Centre, Lydia Becker Institute of Immunology and Inflammation, Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom
| | - Koon Ho Wong
- Faculty of Health Sciences, University of Macau, Macau, China
- Faculty of Health Sciences, Institute of Translational Medicine, University of Macau, Macau, China
| | - Gustavo H. Goldman
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
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Current Promising Therapeutic Targets for Aspergillosis Treatment. JOURNAL OF PURE AND APPLIED MICROBIOLOGY 2021. [DOI: 10.22207/jpam.15.2.09] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Aspergillosis is a fungal disease caused by different species of Aspergillus. They live in soil,dust and decomposed material. Number of Aspergillus species found till now is about 300 and more are still to be identified. Only few Aspergillus species can cause human disease and the most common species for human infection is Aspergillus fumigatus, which is a ubiquitous airborne saprophytic fungus. Severity of the disease ranges from an allergic response to life-threatening generalized infection. They grow optimally at 37°C and can grow upto 50°C. The fungal conidia are being constantly inhaled by humans and animals everyday normally gets eliminated by innate immune mechanism. Due to increasing number of immunocompromised patients, severe and fatal Aspergillosis cases have augmented. Currently, available antifungal drug for the treatment of Aspergillosis act on these three molecular target are 14 alpha demethylase for Azoles, ergosterol for Polyene and β-1,3-glucan synthase for Echinocandin. These antifungal drug show high resistance problem and toxicity. So, it is high time to develop new drugs for treatment with reduced toxicity and drug resistant problem. Synthesis of essential amino acid is absent in human as they obtain it from their diet but fungi synthesis these amino acid. Thus, enzymes in this pathway acts as novel drug target. This article summarizes promising drug targets presents in different metabolic pathway of Aspergillus genome and discusses their molecular functions in detail. This review also list down the inhibitors of these novel target. We present a comprehensive review that will pave way for discovery and development of novel antifungals against these drug targets for Aspergillosis treatment.
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Functional Genomic and Biochemical Analysis Reveals Pleiotropic Effect of Congo Red on Aspergillus fumigatus. mBio 2021; 12:mBio.00863-21. [PMID: 34006660 PMCID: PMC8262895 DOI: 10.1128/mbio.00863-21] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Inhibition of fungal growth by Congo red (CR) has been putatively associated with specific binding to β-1,3-glucans, which blocks cell wall polysaccharide synthesis. In this study, we searched for transcription factors (TFs) that regulate the response to CR and interrogated their regulon. During the investigation of the susceptibility to CR of the TF mutant library, several CR-resistant and -hypersensitive mutants were discovered and further studied. Abnormal distorted swollen conidia called Quasimodo cells were seen in the presence of CR. Quasimodo cells in the resistant mutants were larger than the ones in the sensitive and parental strains; consequently, the conidia of the resistant mutants absorbed more CR than the germinating conidia of the sensitive or parental strains. Accordingly, this higher absorption rate by Quasimodo cells resulted in the removal of CR from the culture medium, allowing a subset of conidia to germinate and grow. In contrast, all resting conidia of the sensitive mutants and the parental strain were killed. This result indicated that the heterogeneity of the conidial population is essential to promote the survival of Aspergillus fumigatus in the presence of CR. Moreover, amorphous surface cell wall polysaccharides such as galactosaminogalactan control the influx of CR inside the cells and, accordingly, resistance to the drug. Finally, long-term incubation with CR led to the discovery of a new CR-induced growth effect, called drug-induced growth stimulation (DIGS), since the growth of one of them could be stimulated after recovery from CR stress.
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Abstract
The fungal zinc finger transcription factor NsdC is named after, and is best known for, its essential role in sexual reproduction (never in sexual development). In previous studies with Aspergillus nidulans, it was also shown to have roles in promotion of vegetative growth and suppression of asexual conidiation. In this study, the function of the nsdC homologue in the opportunistic human pathogen A. fumigatus was investigated. NsdC was again found to be essential for sexual development, with deletion of the nsdC gene in both MAT1-1 and MAT1-2 mating partners of a cross leading to complete loss of fertility. However, a functional copy of nsdC in one mating partner was sufficient to allow sexual reproduction. Deletion of nsdC also led to decreased vegetative growth and allowed conidiation in liquid cultures, again consistent with previous findings. However, NsdC in A. fumigatus was shown to have additional biological functions including response to calcium stress, correct organization of cell wall structure, and response to the cell wall stressors. Furthermore, virulence and host immune recognition were affected. Gene expression studies involving chromatin immunoprecipitation (ChIP) of RNA polymerase II (PolII) coupled to next-generation sequencing (Seq) revealed that deletion of nsdC resulted in changes in expression of over 620 genes under basal growth conditions. This demonstrated that this transcription factor mediates the activity of a wide variety of signaling and metabolic pathways and indicates that despite the naming of the gene, the promotion of sexual reproduction is just one among multiple roles of NsdC.IMPORTANCE Aspergillus fumigatus is an opportunistic human fungal pathogen and the main causal agent of invasive aspergillosis, a life-threatening infection especially in immunocompromised patients. A. fumigatus can undergo both asexual and sexual reproductive cycles, and the regulation of both cycles involves several genes and pathways. Here, we have characterized one of these genetic determinants, the NsdC transcription factor, which was initially identified in a screen of transcription factor null mutants showing sensitivity when exposed to high concentrations of calcium. In addition to its known essential roles in sexual reproduction and control of growth rate and asexual reproduction, we have shown in the present study that A. fumigatus NsdC transcription factor has additional previously unrecognized biological functions including calcium tolerance, cell wall stress response, and correct cell wall organization and functions in virulence and host immune recognition. Our results indicate that NsdC can play novel additional biological functions not directly related to its role played during sexual and asexual processes.
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Zhang X, Cao S, Li W, Sun H, Deng Y, Zhang A, Chen H. Functional Characterization of Calcineurin-Responsive Transcription Factors Fg01341 and Fg01350 in Fusarium graminearum. Front Microbiol 2020; 11:597998. [PMID: 33324378 PMCID: PMC7726117 DOI: 10.3389/fmicb.2020.597998] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 11/05/2020] [Indexed: 11/13/2022] Open
Abstract
Ca2 +/calmodulin-dependent phosphatase calcineurin is one of the important regulators of intracellular calcium homeostasis and has been investigated extensively in Saccharomyces cerevisiae. However, only a few reports have explored the function of the Crz1 homolog in filamentous fungi, especially in Fusarium graminearum. In this study, we identified Fg01341 as a potential ortholog of yeast Crz1. Fg01341 could interact with calcineurin and initiate nuclear transport in a calcineurin-dependent manner. The ΔFg01341 mutant exhibited normal hyphal growth on basic medium and conidia formation, but sexual reproduction was partially blocked. Pathogenicity assays showed that the virulence of the ΔFg01341 mutant in flowering wheat heads and corn silks dramatically decreased and was thus consistent with the reduction in deoxynivalenol production. Unexpectedly, the sensitivity to osmotic stress of the deletion mutant and that of the wild-type strain did not present any differences. The deletion mutant showed higher sensitivity to tebuconazole than the wild-type strain. Results also showed that the transcription factor Fg01350 might be the calcineurin target and was independent of Crz1. Furthermore, ΔFg01350 showed defects in hyphal growth, sexual production, virulence, and deoxynivalenol production. Collectively, the results indicate that these two proteins functionally redundant and that the calcineurin-Crz1-independent pathway is particularly important in F. graminearum.
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Affiliation(s)
- Xiangxiang Zhang
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, China.,The Management of Scientific Research, Jiangsu Coastal Area Institute of Agricultural Sciences, Yancheng, China
| | - Shulin Cao
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Wei Li
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Haiyan Sun
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Yuanyu Deng
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Aixiang Zhang
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Huaigu Chen
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, China
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LeBlanc EV, Polvi EJ, Veri AO, Privé GG, Cowen LE. Structure-guided approaches to targeting stress responses in human fungal pathogens. J Biol Chem 2020; 295:14458-14472. [PMID: 32796038 DOI: 10.1074/jbc.rev120.013731] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 08/11/2020] [Indexed: 11/06/2022] Open
Abstract
Fungi inhabit extraordinarily diverse ecological niches, including the human body. Invasive fungal infections have a devastating impact on human health worldwide, killing ∼1.5 million individuals annually. The majority of these deaths are attributable to species of Candida, Cryptococcus, and Aspergillus Treating fungal infections is challenging, in part due to the emergence of resistance to our limited arsenal of antifungal agents, necessitating the development of novel therapeutic options. Whereas conventional antifungal strategies target proteins or cellular components essential for fungal growth, an attractive alternative strategy involves targeting proteins that regulate fungal virulence or antifungal drug resistance, such as regulators of fungal stress responses. Stress response networks enable fungi to adapt, grow, and cause disease in humans and include regulators that are highly conserved across eukaryotes as well as those that are fungal-specific. This review highlights recent developments in elucidating crystal structures of fungal stress response regulators and emphasizes how this knowledge can guide the design of fungal-selective inhibitors. We focus on the progress that has been made with highly conserved regulators, including the molecular chaperone Hsp90, the protein phosphatase calcineurin, and the small GTPase Ras1, as well as with divergent stress response regulators, including the cell wall kinase Yck2 and trehalose synthases. Exploring structures of these important fungal stress regulators will accelerate the design of selective antifungals that can be deployed to combat life-threatening fungal diseases.
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Affiliation(s)
- Emmanuelle V LeBlanc
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Elizabeth J Polvi
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Amanda O Veri
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Gilbert G Privé
- Departments of Medical Biophysics and Biochemistry, University of Toronto, Toronto, Ontario, Canada.,Princess Margaret Cancer Centre, Toronto, Ontario, Canada
| | - Leah E Cowen
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
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Li H, Zhong JJ. Role of calcineurin-responsive transcription factor CRZ1 in ganoderic acid biosynthesis by Ganoderma lucidum. Process Biochem 2020. [DOI: 10.1016/j.procbio.2020.05.027] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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14
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Abstract
Aspergillus fumigatus, one of the most important human-pathogenic fungal species, is able to cause aspergillosis, a heterogeneous group of diseases that presents a wide range of clinical manifestations. Invasive pulmonary aspergillosis is the most serious pathology in terms of patient outcome and treatment, with a high mortality rate ranging from 50% to 95% primarily affecting immunocompromised patients. Azoles have been used for many years as the main antifungal agents to treat and prevent invasive aspergillosis. However, there were several reports of evolution of clinical azole resistance in the last decade. Caspofungin, a noncompetitive β-1,3-glucan synthase inhibitor, has been used against A. fumigatus, but it is fungistatic and is recommended as second-line therapy for invasive aspergillosis. More information about caspofungin tolerance and resistance is necessary in order to refine antifungal strategies that target the fungal cell wall. Here, we screened a transcription factor (TF) deletion library for TFs that can mediate caspofungin tolerance and resistance. We have identified 11 TFs that are important for caspofungin sensitivity and/or for the caspofungin paradoxical effect (CPE). These TFs encode proteins involved in the basal modulation of the RNA polymerase II initiation sites, calcium metabolism or cell wall remodeling, and mitochondrial respiratory function. The study of those genes regulated by TFs identified in this work will provide a better understanding of the signaling pathways that are important for caspofungin tolerance and resistance. Aspergillus fumigatus is the leading cause of pulmonary fungal diseases. Azoles have been used for many years as the main antifungal agents to treat and prevent invasive aspergillosis. However, in the last 10 years there have been several reports of azole resistance in A. fumigatus and new strategies are needed to combat invasive aspergillosis. Caspofungin is effective against other human-pathogenic fungal species, but it is fungistatic only against A. fumigatus. Resistance to caspofungin in A. fumigatus has been linked to mutations in the fksA gene that encodes the target enzyme of the drug β-1,3-glucan synthase. However, tolerance of high caspofungin concentrations, a phenomenon known as the caspofungin paradoxical effect (CPE), is also important for subsequent adaptation and drug resistance evolution. Here, we identified and characterized the transcription factors involved in the response to CPE by screening an A. fumigatus library of 484 null transcription factors (TFs) in CPE drug concentrations. We identified 11 TFs that had reduced CPE and that encoded proteins involved in the basal modulation of the RNA polymerase II initiation sites, calcium metabolism, and cell wall remodeling. One of these TFs, FhdA, was important for mitochondrial respiratory function and iron metabolism. The ΔfhdA mutant showed decreased growth when exposed to Congo red or to high temperature. Transcriptome sequencing (RNA-seq) analysis and further experimental validation indicated that the ΔfhdA mutant showed diminished respiratory capacity, probably affecting several pathways related to the caspofungin tolerance and resistance. Our results provide the foundation to understand signaling pathways that are important for caspofungin tolerance and resistance.
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15
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de Castro PA, Colabardini AC, Manfiolli AO, Chiaratto J, Silva LP, Mattos EC, Palmisano G, Almeida F, Persinoti GF, Ries LNA, Mellado L, Rocha MC, Bromley M, Silva RN, de Souza GS, Loures FV, Malavazi I, Brown NA, Goldman GH. Aspergillus fumigatus calcium-responsive transcription factors regulate cell wall architecture promoting stress tolerance, virulence and caspofungin resistance. PLoS Genet 2019; 15:e1008551. [PMID: 31887136 PMCID: PMC6948819 DOI: 10.1371/journal.pgen.1008551] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 01/08/2020] [Accepted: 12/02/2019] [Indexed: 11/28/2022] Open
Abstract
Aspergillus fumigatus causes invasive aspergillosis, the most common life-threatening fungal disease of immuno-compromised humans. The treatment of disseminated infections with antifungal drugs, including echinocandin cell wall biosynthesis inhibitors, is increasingly challenging due to the rise of drug-resistant pathogens. The fungal calcium responsive calcineurin-CrzA pathway influences cell morphology, cell wall composition, virulence, and echinocandin resistance. A screen of 395 A. fumigatus transcription factor mutants identified nine transcription factors important to calcium stress tolerance, including CrzA and ZipD. Here, comparative transcriptomics revealed CrzA and ZipD regulated the expression of shared and unique gene networks, suggesting they participate in both converged and distinct stress response mechanisms. CrzA and ZipD additively promoted calcium stress tolerance. However, ZipD also regulated cell wall organization, osmotic stress tolerance and echinocandin resistance. The absence of ZipD in A. fumigatus caused a significant virulence reduction in immunodeficient and immunocompetent mice. The ΔzipD mutant displayed altered cell wall organization and composition, while being more susceptible to macrophage killing and eliciting an increased pro-inflammatory cytokine response. A higher number of neutrophils, macrophages and activated macrophages were found in ΔzipD infected mice lungs. Collectively, this shows that ZipD-mediated regulation of the fungal cell wall contributes to the evasion of pro-inflammatory responses and tolerance of echinocandin antifungals, and in turn promoting virulence and complicating treatment options.
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Affiliation(s)
- Patrícia Alves de Castro
- Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Ana Cristina Colabardini
- Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Adriana Oliveira Manfiolli
- Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Jéssica Chiaratto
- Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Lilian Pereira Silva
- Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Eliciane Cevolani Mattos
- Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Giuseppe Palmisano
- Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
| | - Fausto Almeida
- Departamento de Bioquímica e Imunologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Gabriela Felix Persinoti
- Laboratório Nacional de Biorrenováveis (LNBR), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Campinas, São Paulo, Brasil
| | - Laure Nicolas Annick Ries
- Departamento de Bioquímica e Imunologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Laura Mellado
- Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Marina Campos Rocha
- Departamento de Genética e Evolução, Centro de Ciências Biológicas e da Saúde, Universidade Federal de São Carlos, São Carlos, São Paulo, Brazil
| | - Michael Bromley
- Manchester Fungal Infection Group, Institute of Inflammation and Repair, University of Manchester, Manchester, United Kingdom
| | - Roberto Nascimento Silva
- Departamento de Bioquímica e Imunologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Gabriel Scalini de Souza
- Instituto de Ciência e Tecnologia, Universidade Federal de São Paulo, São José dos Campos, Brazil
| | - Flávio Vieira Loures
- Instituto de Ciência e Tecnologia, Universidade Federal de São Paulo, São José dos Campos, Brazil
| | - Iran Malavazi
- Departamento de Genética e Evolução, Centro de Ciências Biológicas e da Saúde, Universidade Federal de São Carlos, São Carlos, São Paulo, Brazil
| | - Neil Andrew Brown
- Department of Biology & Biochemistry, University of Bath, Claverton Down, Bath, United Kingdom
| | - Gustavo H Goldman
- Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
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16
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Function of crzA in Fungal Development and Aflatoxin Production in Aspergillus flavus. Toxins (Basel) 2019; 11:toxins11100567. [PMID: 31569747 PMCID: PMC6832762 DOI: 10.3390/toxins11100567] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 09/26/2019] [Accepted: 09/27/2019] [Indexed: 12/11/2022] Open
Abstract
The calcineurin pathway is an important signaling cascade for growth, sexual development, stress response, and pathogenicity in fungi. In this study, we investigated the function of CrzA, a key transcription factor of the calcineurin pathway, in an aflatoxin-producing fungus Aspergillus flavus (A. flavus). To examine the role of the crzA gene, crzA deletion mutant strains in A. flavus were constructed and their phenotypes, including fungal growth, spore formation, and sclerotial formation, were examined. Absence of crzA results in decreased colony growth, the number of conidia, and sclerocia production. The crzA-deficient mutant strains were more susceptible to osmotic pressure and cell wall stress than control or complemented strains. Moreover, deletion of crzA results in a reduction in aflatoxin production. Taken together, these results demonstrate that CrzA is important for differentiation and mycotoxin production in A. flavus.
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17
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The Aspergillus fumigatus Mucin MsbA Regulates the Cell Wall Integrity Pathway and Controls Recognition of the Fungus by the Immune System. mSphere 2019; 4:4/3/e00350-19. [PMID: 31217305 PMCID: PMC6584374 DOI: 10.1128/msphere.00350-19] [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] [Indexed: 12/21/2022] Open
Abstract
Aspergillus fumigatus is a filamentous fungus which causes invasive pulmonary aspergillosis in immunocompromised individuals. In fungi, cell signaling and cell wall plasticity are crucial for maintaining physiologic processes. In this context, Msb2 is an important signaling mucin responsible for activation of a variety of mitogen-activated protein kinase (MAPK)-dependent signaling pathways that regulate cell growth in several organisms, such as the cell wall integrity (CWI) pathway. Here, we aimed to characterize the MSB2 homologue in A. fumigatus Our results showed that MsbA plays a role in the vegetative and reproductive development of the fungus, in stress adaptation, and in resistance to antifungal drugs by modulating the CWI pathway gene expression. Importantly, cell wall composition is also responsible for activation of diverse receptors of the host immune system, thus leading to a proper immune response. In a model of acute Aspergillus pulmonary infection, results demonstrate that the ΔmsbA mutant strain induced less inflammation with diminished cell influx into the lungs and lower cytokine production, culminating in increased lethality rate. These results characterize for the first time the role of the signaling mucin MsbA in the pathogen A. fumigatus, as a core sensor for cell wall morphogenesis and an important regulator of virulence.IMPORTANCE Aspergillus fumigatus is an opportunistic fungus with great medical importance. During infection, Aspergillus grows, forming hyphae that colonize the lung tissue and invade and spread over the mammal host, resulting in high mortality rates. The knowledge of the mechanisms responsible for regulation of fungal growth and virulence comprises an important point to better understand fungal physiology and host-pathogen interactions. Msb2 is a mucin that acts as a sensor and an upstream regulator of the MAPK pathway responsible for fungal development in Candida albicans and Aspergillus nidulans Here, we show the role of the signaling mucin MsbA in the pathogen A. fumigatus, as a core sensor for cell wall morphogenesis, fungal growth, and virulence. Moreover, we show that cell wall composition, controlled by MsbA, is detrimental for fungal recognition and clearance by immune cells. Our findings are important for the understanding of how fungal sensors modulate cell physiology.
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18
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Woo PCY, Lau SKP, Lau CCY, Tung ETK, Au-Yeung RKH, Cai JP, Chong KTK, Sze KH, Kao RY, Hao Q, Yuen KY. Mp1p homologues as virulence factors in Aspergillus fumigatus. Med Mycol 2019; 56:350-360. [PMID: 28992243 DOI: 10.1093/mmy/myx052] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2016] [Accepted: 07/20/2017] [Indexed: 01/17/2023] Open
Abstract
Recently, we showed that Mp1p is an important virulence factor of Talaromyces marneffei, a dimorphic fungus phylogenetically closely related to Aspergillus fumigatus. In this study, we investigated the virulence properties of the four Mp1p homologues (Afmp1p, Afmp2p, Afmp3p, and Afmp4p) in A. fumigatus using a mouse model. All mice died 7 days after challenge with wild-type A. fumigatus QC5096, AFMP1 knockdown mutant, AFMP2 knockdown mutant and AFMP3 knockdown mutant and 28 days after challenge with AFMP4 knockdown mutant (P<.0001). Only 11% of mice died 30 days after challenge with AFMP1-4 knockdown mutant (P<.0001). For mice challenge with AFMP1-4 knockdown mutant, lower abundance of fungal elements was observed in brains, kidneys, and spleens compared to mice challenge with QC5096 at day 4 post-infection. Fungal counts in brains of mice challenge with QC5096 or AFMP4 knockdown mutant were significantly higher than those challenge with AFMP1-4 knockdown mutant (P<.01 and P<.05). Fungal counts in kidneys of mice challenge with QC5096 or AFMP4 knockdown mutant were significantly higher than those challenge with AFMP1-4 knockdown mutant (P<.001 and P<.001) and those of mice challenge with QC5096 were significantly higher than those challenge with AFMP4 knockdown mutant (P<.05). There is no difference among the survival rates of wild-type A. fumigatus, AFMP4 knockdown mutant and AFMP1-4 knockdown mutant, suggesting that Mp1p homologues in A. fumigatus do not mediate its virulence via improving its survival in macrophage as in the case in T. marneffei. Afmp1p, Afmp2p, Afmp3p, and Afmp4p in combination are important virulence factors of A. fumigatus.
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Affiliation(s)
- Patrick C Y Woo
- Department of Microbiology, The University of Hong Kong, Hong Kong.,State Key Laboratory of Emerging Infectious Diseases, The University of Hong Kong, Hong Kong.,Research Centre of Infection and Immunology, The University of Hong Kong, Hong Kong.,Carol Yu Centre for Infection, The University of Hong Kong, Hong Kong.,Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The University of Hong Kong, Hong Kong
| | - Susanna K P Lau
- Department of Microbiology, The University of Hong Kong, Hong Kong.,State Key Laboratory of Emerging Infectious Diseases, The University of Hong Kong, Hong Kong.,Research Centre of Infection and Immunology, The University of Hong Kong, Hong Kong.,Carol Yu Centre for Infection, The University of Hong Kong, Hong Kong.,Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The University of Hong Kong, Hong Kong
| | - Candy C Y Lau
- Department of Microbiology, The University of Hong Kong, Hong Kong
| | - Edward T K Tung
- Department of Microbiology, The University of Hong Kong, Hong Kong
| | - Rex K H Au-Yeung
- Department of Pathology, The University of Hong -Kong, Hong Kong
| | - Jian-Pao Cai
- Department of Microbiology, The University of Hong Kong, Hong Kong
| | - Ken T K Chong
- Department of Microbiology, The University of Hong Kong, Hong Kong
| | - Kong Hung Sze
- Department of Microbiology, The University of Hong Kong, Hong Kong.,State Key Laboratory of Emerging Infectious Diseases, The University of Hong Kong, Hong Kong.,Research Centre of Infection and Immunology, The University of Hong Kong, Hong Kong.,Carol Yu Centre for Infection, The University of Hong Kong, Hong Kong
| | - Richard Y Kao
- Department of Microbiology, The University of Hong Kong, Hong Kong.,State Key Laboratory of Emerging Infectious Diseases, The University of Hong Kong, Hong Kong.,Research Centre of Infection and Immunology, The University of Hong Kong, Hong Kong.,Carol Yu Centre for Infection, The University of Hong Kong, Hong Kong
| | - Quan Hao
- School of Biomedical Sciences, The University of Hong Kong, Hong Kong
| | - Kwok-Yung Yuen
- Department of Microbiology, The University of Hong Kong, Hong Kong.,State Key Laboratory of Emerging Infectious Diseases, The University of Hong Kong, Hong Kong.,Research Centre of Infection and Immunology, The University of Hong Kong, Hong Kong.,Carol Yu Centre for Infection, The University of Hong Kong, Hong Kong.,Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The University of Hong Kong, Hong Kong
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19
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Shwab EK, Juvvadi PR, Waitt G, Soderblom EJ, Barrington BC, Asfaw YG, Moseley MA, Steinbach WJ. Calcineurin-dependent dephosphorylation of the transcription factor CrzA at specific sites controls conidiation, stress tolerance, and virulence of Aspergillus fumigatus. Mol Microbiol 2019; 112:62-80. [PMID: 30927289 DOI: 10.1111/mmi.14254] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/24/2019] [Indexed: 12/15/2022]
Abstract
Calcium signaling through calcineurin and its major transcription factor (TF), CrzA, is integral to hyphal growth, stress response and virulence of the pathogenic fungus Aspergillus fumigatus, the leading etiology of invasive aspergillosis. Dephosphorylation of CrzA by calcineurin activates the TF, but the specific phosphorylation sites and their roles in the activation/inactivation mechanism are unknown. Mass spectroscopic analysis identified 20 phosphorylation sites, the majority of which were specific to filamentous fungi and distributed throughout the CrzA protein, with particular concentration in a serine-rich region N-terminal to the conserved DNA-binding domain (DBD). Site-directed mutagenesis of phosphorylated residues revealed that CrzA activity during calcium stimulation can only be suppressed by a high degree of phosphorylation in multiple regions of the protein. Our findings further suggest that this regulation is not solely accomplished through control of CrzA nuclear import. Additionally, we demonstrate the importance of the CrzA phosphorylation state in regulating growth, conidiation, calcium and cell wall stress tolerance, and virulence. Finally, we identify two previously undescribed nuclear localization sequences in the DBD. These findings provide novel insight into the phosphoregulation of CrzA which may be exploited to selectively target A. fumigatus.
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Affiliation(s)
- E Keats Shwab
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Duke University Medical Center, Durham, NC, USA
| | - Praveen R Juvvadi
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Duke University Medical Center, Durham, NC, USA
| | - Greg Waitt
- Duke Proteomics and Metabolomics Core Facility, Center for Genomic and Computational Biology, Duke University, Durham, NC, USA
| | - Erik J Soderblom
- Duke Proteomics and Metabolomics Core Facility, Center for Genomic and Computational Biology, Duke University, Durham, NC, USA
| | - Blake C Barrington
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Duke University Medical Center, Durham, NC, USA
| | - Yohannes G Asfaw
- Department of Laboratory Animal Resources, Duke University Medical Center, Durham, NC, USA
| | - M Arthur Moseley
- Duke Proteomics and Metabolomics Core Facility, Center for Genomic and Computational Biology, Duke University, Durham, NC, USA
| | - William J Steinbach
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Duke University Medical Center, Durham, NC, USA.,Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, USA
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20
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Klebsiella pneumoniae prevents spore germination and hyphal development of Aspergillus species. Sci Rep 2019; 9:218. [PMID: 30659217 PMCID: PMC6338788 DOI: 10.1038/s41598-018-36524-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2018] [Accepted: 11/20/2018] [Indexed: 12/29/2022] Open
Abstract
Different bacteria and fungi live as commensal organisms as part of the human microbiota, but shifts to a pathogenic state potentially leading to septic infections commonly occur in immunocompromised individuals. Several studies have reported synergistic or antagonistic interactions between individual bacteria and fungi which might be of clinical relevance. Here, we present first evidence for the interaction between Klebsiella pneumoniae and several Aspergillus species including A. fumigatus, A. terreus, A. niger and A. flavus which cohabit in the lungs and the intestines. Microbiological and molecular methods were employed to investigate the interaction in vitro, and the results indicate that Klebsiella pneumoniae is able to prevent Aspergillus spp. spore germination and hyphal development. The inhibitory effect is reversible, as demonstrated by growth recovery of Aspergillus spp. upon inhibition or elimination of the bacteria, and is apparently dependent on the physical interaction with metabolically active bacteria. Molecular analysis of Klebsiella-Aspergillus interaction has shown upregulation of Aspergillus cell wall-related genes and downregulation of hyphae-related genes, suggesting that Klebsiella induces cell wall stress response mechanisms and suppresses filamentous growth. Characterization of polymicrobial interactions may provide the basis for improved clinical management of mixed infections by setting the stage for appropriate diagnostics and ultimately for optimized treatment strategies.
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21
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Blachowicz A, Chiang AJ, Romsdahl J, Kalkum M, Wang CCC, Venkateswaran K. Proteomic characterization of Aspergillus fumigatus isolated from air and surfaces of the International Space Station. Fungal Genet Biol 2019; 124:39-46. [PMID: 30611835 DOI: 10.1016/j.fgb.2019.01.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Revised: 12/18/2018] [Accepted: 01/02/2019] [Indexed: 12/13/2022]
Abstract
The on-going Microbial Observatory Experiments on the International Space Station (ISS) revealed the presence of various microorganisms that may be affected by the distinct environment of the ISS. The low-nutrient environment combined with enhanced irradiation and microgravity may trigger changes in the molecular suite of microorganisms leading to increased virulence and resistance of microbes. Proteomic characterization of two Aspergillus fumigatus strains, ISSFT-021 and IF1SW-F4, isolated from HEPA filter debris and cupola surface of the ISS, respectively, is presented, along with a comparison to well-studied clinical isolates Af293 and CEA10. In-depth analysis highlights variations in the proteome of both ISS-isolated strains when compared to the clinical strains. Proteins that showed increased abundance in ISS isolates were overall involved in stress responses, and carbohydrate and secondary metabolism. Among the most abundant proteins were Pst2 and ArtA involved in oxidative stress response, PdcA and AcuE responsible for ethanol fermentation and glyoxylate cycle, respectively, TpcA, TpcF, and TpcK that are part of trypacidin biosynthetic pathway, and a toxin Asp-hemolysin. This report provides insight into possible molecular adaptation of filamentous fungi to the unique ISS environment.
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Affiliation(s)
- Adriana Blachowicz
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA, USA; Biotechnology and Planetary Protection Group, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - Abby J Chiang
- Department of Molecular Immunology, Beckman Research Institute of City of Hope, Duarte, CA, USA
| | - Jillian Romsdahl
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA, USA
| | - Markus Kalkum
- Department of Molecular Immunology, Beckman Research Institute of City of Hope, Duarte, CA, USA
| | - Clay C C Wang
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA, USA; Department of Chemistry, Dornsife College of Letters, Arts, and Sciences, University of Southern California, Los Angeles, CA, USA.
| | - Kasthuri Venkateswaran
- Biotechnology and Planetary Protection Group, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA.
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22
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Escobar N, Valdes ID, Keizer EM, Ordonez SR, Ohm RA, Wösten HAB, de Cock H. Expression profile analysis reveals that Aspergillus fumigatus but not Aspergillus niger makes type II epithelial lung cells less immunological alert. BMC Genomics 2018; 19:534. [PMID: 30005605 PMCID: PMC6044037 DOI: 10.1186/s12864-018-4895-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 06/25/2018] [Indexed: 12/17/2022] Open
Abstract
Background Aspergillus fumigatus is the main causative agent of aspergillosis. Infections rarely occur in immunocompetent individuals, indicating efficient clearance of conidia by pulmonary defense mechanisms. Other aspergilli like Aspergillus niger also cause infections but to a much lesser extent. Our previous studies showed that A. fumigatus and A. niger have different behavior in the presence of type II alveolar A549 epithelial cells. A. fumigatus conidia are more efficiently internalized by these cells and germination is delayed when compared to A. niger. In addition, hyphae that have escaped the epithelial cells grow parallel to the epithelium, while A. niger grows away from this cell layer. Results Here it is shown that global gene expression of A. fumigatus and A. niger is markedly different upon contact with A549 cells. A total of 545 and 473 genes of A. fumigatus and A. niger, respectively, were differentially expressed when compared to growth in the absence of A549 cells. Notably, only 53 genes (approximately 10%) were shared in these gene sets. The different response was also illustrated by the fact that only 4 out of 75 GO terms were shared that were enriched in the differentially expressed gene sets. The orthologues of A. fumigatus genes involved in hypoxia regulation and heat shock were also up-regulated in A. niger, whereas thioredoxin reductase and allergen genes were found up-regulated in A. fumigatus but down-regulated in A. niger. Infection with A. fumigatus resulted in only 62 up and 47 down-regulated genes in A549. These numbers were 17 and 34 in the case of A. niger. GO terms related with immune response were down-regulated upon exposure to A. fumigatus but not in the case of A. niger. This indicates that A. fumigatus reprograms A549 to be less immunologically alert. Conclusions Our dual transcriptomic analysis supports earlier observations of a marked difference in life style between A. fumigatus and A. niger when grown in the presence of type II epithelial cells. The results indicate important differences in gene expression, amongst others down regulation of immune response genes in lung epithelial cells by A. fumigatus but not by A niger. Electronic supplementary material The online version of this article (10.1186/s12864-018-4895-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Natalia Escobar
- Microbiology & Institute of Biomembranes, Department of Biology, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands
| | - Ivan D Valdes
- Microbiology & Institute of Biomembranes, Department of Biology, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands
| | - Esther M Keizer
- Microbiology & Institute of Biomembranes, Department of Biology, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands
| | - Soledad R Ordonez
- Department of Infectious Diseases and Immunology, Division Molecular Host Defence, Utrecht University, Yalelaan 1, 3584CL, Utrecht, The Netherlands
| | - Robin A Ohm
- Microbiology & Institute of Biomembranes, Department of Biology, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands
| | - Han A B Wösten
- Microbiology & Institute of Biomembranes, Department of Biology, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands
| | - Hans de Cock
- Microbiology & Institute of Biomembranes, Department of Biology, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands.
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23
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Dissecting the Roles of the Calcineurin Pathway in Unisexual Reproduction, Stress Responses, and Virulence in Cryptococcus deneoformans. Genetics 2017; 208:639-653. [PMID: 29233811 DOI: 10.1534/genetics.117.300422] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Accepted: 12/07/2017] [Indexed: 01/12/2023] Open
Abstract
The Ca2+/calmodulin-dependent protein phosphatase calcineurin orchestrates sexual reproduction, stress responses, and virulence via branched downstream pathways in the opportunistic human fungal pathogen Cryptococcus neoformans The calcineurin-binding protein Cbp1, the calcineurin temperature suppressor Cts1, the calcineurin-responsive zinc finger transcription factor Crz1, and the calcineurin targets Pbp1, Tif3, and Puf4, all function downstream of calcineurin to orchestrate distinct cellular processes. To elucidate how the calcineurin pathway regulatory network governs unisexual reproduction, stress responses, and virulence, we have analyzed the self-filamentous C. deneoformans strain, XL280α, and generated double mutants of these calcineurin downstream genes. We demonstrated that calcineurin governs unisexual reproduction at different sexual developmental stages, in which the initiation of the yeast-hyphal morphological transition is independent of Crz1, whereas the sporulation process is dependent on Crz1. Calcineurin-dependent unisexual reproduction is independent of the pheromone response pathway. Crz1 synergistically interacts with different calcineurin downstream targets in responding to ER, high-calcium, and cell wall stresses. We observed a widespread synergy suggesting that these proteins function in complex branched pathways downstream of calcineurin with some functional redundancy, which may allow efficient signaling network rewiring within the pathway for prompt adaptation to changing environments. Finally, we showed that deletion of PBP1 or TIF3 in the cna1∆ mutant background conferred a modest level of growth tolerance at 37°, but that the cna1∆ pbp1∆ and cna1∆ tif3∆ double mutants were both avirulent, suggesting that calcineurin may control virulence via mechanisms beyond thermotolerance.
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Etxebeste O, Espeso EA. Neurons show the path: tip-to-nucleus communication in filamentous fungal development and pathogenesis. FEMS Microbiol Rev 2017; 40:610-24. [PMID: 27587717 DOI: 10.1093/femsre/fuw021] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/17/2016] [Indexed: 01/11/2023] Open
Abstract
Multiple fungal species penetrate substrates and accomplish host invasion through the fast, permanent and unidirectional extension of filamentous cells known as hyphae. Polar growth of hyphae results, however, in a significant increase in the distance between the polarity site, which also receives the earliest information about ambient conditions, and nuclei, where adaptive responses are executed. Recent studies demonstrate that these long distances are overcome by signal transduction pathways which convey sensory information from the polarity site to nuclei, controlling development and pathogenesis. The present review compares the striking connections of the mechanisms for long-distance communication in hyphae with those from neurons, and discusses the importance of their study in order to understand invasion and dissemination processes of filamentous fungi, and design strategies for developmental control in the future.
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Affiliation(s)
- Oier Etxebeste
- Biochemistry II laboratory, Department of Applied Chemistry, Faculty of Chemistry, University of the Basque Country (UPV/EHU), 20018 San Sebastian, Spain
| | - Eduardo A Espeso
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas (CSIC), Ramiro de Maeztu 9, 28040 Madrid, Spain
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Loss O, Bertuzzi M, Yan Y, Fedorova N, McCann BL, Armstrong-James D, Espeso EA, Read ND, Nierman WC, Bignell EM. Mutual independence of alkaline- and calcium-mediated signalling in Aspergillus fumigatus refutes the existence of a conserved druggable signalling nexus. Mol Microbiol 2017; 106:861-875. [PMID: 28922497 PMCID: PMC5725717 DOI: 10.1111/mmi.13840] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/13/2017] [Indexed: 01/03/2023]
Abstract
Functional coupling of calcium‐ and alkaline responsive signalling occurs in multiple fungi to afford efficient cation homeostasis. Host microenvironments exert alkaline stress and potentially toxic concentrations of Ca2+, such that highly conserved regulators of both calcium‐ (Crz) and pH‐ (PacC/Rim101) responsive signalling are crucial for fungal pathogenicity. Drugs targeting calcineurin are potent antifungal agents but also perturb human immunity thereby negating their use as anti‐infectives, abrogation of alkaline signalling has, therefore, been postulated as an adjunctive antifungal strategy. We examined the interdependency of pH‐ and calcium‐mediated signalling in Aspergillus fumigatus and found that calcium chelation severely impedes hyphal growth indicating a critical requirement for this ion independently of ambient pH. Transcriptomic responses to alkaline pH or calcium excess exhibited minimal similarity. Mutants lacking calcineurin, or its client CrzA, displayed normal alkaline tolerance and nuclear translocation of CrzA was unaffected by ambient pH. Expression of a highly conserved, alkaline‐regulated, sodium ATPase was tolerant of genetic or chemical perturbations of calcium‐mediated signalling, but abolished in null mutants of the pH‐responsive transcription factor PacC, and PacC proteolytic processing occurred normally during calcium excess. Taken together our data demonstrate that in A. fumigatus the regulatory hierarchy governing alkaline tolerance circumvents calcineurin signalling.
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Affiliation(s)
- Omar Loss
- Microbiology Section, Centre for Molecular Microbiology and Infection, Imperial College London, London SW7 2AZ, UK
| | - Margherita Bertuzzi
- Manchester Fungal Infection Group, Division of Infection, Immunity and Respiratory Medicine, University of Manchester, Manchester M13 9NT, UK
| | - Yu Yan
- The J. Craig Venter Institute, Infectious Diseases Program, Rockville, MD, USA
| | - Natalie Fedorova
- The J. Craig Venter Institute, Infectious Diseases Program, Rockville, MD, USA
| | - Bethany L McCann
- Manchester Fungal Infection Group, Division of Infection, Immunity and Respiratory Medicine, University of Manchester, Manchester M13 9NT, UK
| | - Darius Armstrong-James
- Fungal Pathogens Laboratory, National Heart and Lung Institute, Imperial College London SW7 2AY, UK
| | - Eduardo A Espeso
- Department of Molecular and Cellular Biology, Centro de Investigaciones Biologicas (C.S.I.C.), Madrid, Spain
| | - Nick D Read
- Manchester Fungal Infection Group, Division of Infection, Immunity and Respiratory Medicine, University of Manchester, Manchester M13 9NT, UK
| | - William C Nierman
- The J. Craig Venter Institute, Infectious Diseases Program, Rockville, MD, USA
| | - Elaine M Bignell
- Manchester Fungal Infection Group, Division of Infection, Immunity and Respiratory Medicine, University of Manchester, Manchester M13 9NT, UK
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Generation of an arginine-tRNA-adapted Saccharomyces cerevisiae strain for effective heterologous protein expression. Curr Genet 2017; 64:589-598. [PMID: 29098364 DOI: 10.1007/s00294-017-0774-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Revised: 09/30/2017] [Accepted: 10/27/2017] [Indexed: 10/18/2022]
Abstract
The tRNA population reflects the codon bias of the organism and affects the translation of heterologous target mRNA molecules. In this study, Saccharomyces cerevisiae strains with modified levels of rare tRNA were engineered, that allowed efficient generation of recombinant proteins with unfavorable codon usage. We established a novel synthetic tRNA expression cassette and verified functional nonsense suppressor tRNAGlnSCUA generation in a stop codon read-through assay with a modified β-galactosidase reporter gene. Correlation between altered tRNA and protein level was shown by survival of copper sensitive S. cerevisiae cells in the presence of copper ions by an increased transcription of tRNAArgCCG molecules, recognizing rare codons in a modified CUP1 gene. Genome integration of tRNA expression cassette led to the generation of arginine-tRNA-adapted S. cerevisiae strains, which showed elevated tRNA levels (tRNAArgCCG, tRNAArgGCG and tRNAArgUCG) pairing to rare codons. The modified strain MNY3 revealed a considerably improved monitoring of protein-protein interaction from Aspergillus fumigatus bait and prey sequences in yeast two-hybrid experiments. In future, this principle to overcome limited recombinant protein expression by tRNA adaption of expression strains instead of codon adaption might provide new designer yeast cells for an efficient protein production and for improved genome-wide protein-protein interaction analyses.
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Chow EWL, Clancey SA, Billmyre RB, Averette AF, Granek JA, Mieczkowski P, Cardenas ME, Heitman J. Elucidation of the calcineurin-Crz1 stress response transcriptional network in the human fungal pathogen Cryptococcus neoformans. PLoS Genet 2017; 13:e1006667. [PMID: 28376087 PMCID: PMC5380312 DOI: 10.1371/journal.pgen.1006667] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 03/01/2017] [Indexed: 12/02/2022] Open
Abstract
Calcineurin is a highly conserved Ca2+/calmodulin-dependent serine/threonine-specific protein phosphatase that orchestrates cellular Ca2+ signaling responses. In Cryptococcus neoformans, calcineurin is activated by multiple stresses including high temperature, and is essential for stress adaptation and virulence. The transcription factor Crz1 is a major calcineurin effector in Saccharomyces cerevisiae and other fungi. Calcineurin dephosphorylates Crz1, thereby enabling Crz1 nuclear translocation and transcription of target genes. Here we show that loss of Crz1 confers phenotypes intermediate between wild-type and calcineurin mutants, and demonstrate that deletion of the calcineurin docking domain results in the inability of Crz1 to translocate into the nucleus under thermal stress. RNA-sequencing revealed 102 genes that are regulated in a calcineurin-Crz1-dependent manner at 37°C. The majority of genes were down-regulated in cna1Δ and crz1Δ mutants, indicating these genes are normally activated by the calcineurin-Crz1 pathway at high temperature. About 58% of calcineurin-Crz1 target genes have unknown functions, while genes with known or predicted functions are involved in cell wall remodeling, calcium transport, and pheromone production. We identified three calcineurin-dependent response element motifs within the promoter regions of calcineurin-Crz1 target genes, and show that Crz1 binding to target gene promoters is increased upon thermal stress in a calcineurin-dependent fashion. Additionally, we found a large set of genes independently regulated by calcineurin, and Crz1 regulates 59 genes independently of calcineurin. Given the intermediate crz1Δ mutant phenotype, and our recent evidence for a calcineurin regulatory network impacting mRNA in P-bodies and stress granules independently of Crz1, calcineurin likely acts on factors beyond Crz1 that govern mRNA expression/stability to operate a branched transcriptional/post-transcriptional stress response network necessary for fungal virulence. Taken together, our findings reveal the core calcineurin-Crz1 stress response cascade is maintained from ascomycetes to a pathogenic basidiomycete fungus, but its output in C. neoformans appears to be adapted to promote fungal virulence. The ubquitiously conserved serine/threonine-specific protein phosphatase calcineurin is crucial for virulence of several opportunistic human fungal pathogens including Candida albicans, Aspergillus fumigatus, and Cryptococcus neoformans. We show that Crz1 acts downstream of calcineurin, to 1) govern expression of genes involved in cell wall integrity, and calcium and small molecule transport, and 2) contribute to stress survival and virulence of C. neoformans. Our studies reveal that calcineurin also controls mRNA expression levels of other genes independently of Crz1. We propose that calcineurin operates in a branched signal transduction cascade controlling targets at both the transcriptional and post-transcriptional levels.
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Affiliation(s)
- Eve W. L. Chow
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Shelly A. Clancey
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - R. Blake Billmyre
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Anna Floyd Averette
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Joshua A. Granek
- Department of Biostatistics and Bioinformatics, Duke University Medical Center, Durham, North Carolina, United States of America
- Duke Center for the Genomics of Microbial Systems, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Piotr Mieczkowski
- High-Throughput Sequencing Facility, School of Medicine, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Maria E. Cardenas
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Joseph Heitman
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America
- * E-mail:
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Hernández-Ortiz P, Espeso EA. Spatiotemporal dynamics of the calcineurin target CrzA. Cell Signal 2016; 29:168-180. [PMID: 27832964 DOI: 10.1016/j.cellsig.2016.11.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Revised: 09/26/2016] [Accepted: 11/05/2016] [Indexed: 01/23/2023]
Abstract
The response of Aspergilli to elevated concentrations of extracellular calcium and manganese, or environmental alkalinization is mediated by CrzA, a calcineurin-responsive transcription factor (TF). CrzA is the effector of a signaling pathway which includes the apical protein's calmodulin and calcineurin, and the protein kinases GskA and CkiA. Preferentially located in the cytoplasm, CrzA is the only element of the pathway modifying its localization under those stress conditions, being imported into nuclei. Remarkably, there is a direct relationship between the nature/intensity of the stimulus and the pace of nuclear import and time of nuclear permanence of CrzA. Alkalinity caused a transient nuclear accumulation of CrzA while high Ca2+ and Mn2+ concentrations generated a long-lasting accumulation. Furthermore, Ca2+ concentrations (below 5mM) that are non-toxic for a crzAΔ mutant promoted full signaling of CrzA. However, micromolar concentrations or a mutation disrupting the interaction of CrzA with the phosphatase complex calcineurin, permitted the visualization of a transient and polarized nuclear accumulation of the TF in a tip-to-base gradient. Overall, these results support a model in which nucleo-cytoplasmic dynamics and transcriptional activity of CrzA are driven by apical signals transmitted by calmodulin and calcineurin. This communication is essential to understand Ca+2-induced stress response in fungi.
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Affiliation(s)
- Patricia Hernández-Ortiz
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas, CSIC, Madrid, Spain
| | - Eduardo A Espeso
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas, CSIC, Madrid, Spain.
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Bultman KM, Kowalski CH, Cramer RA. Aspergillus fumigatus virulence through the lens of transcription factors. Med Mycol 2016; 55:24-38. [PMID: 27816905 DOI: 10.1093/mmy/myw120] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Revised: 08/19/2016] [Accepted: 10/17/2016] [Indexed: 02/07/2023] Open
Abstract
Invasive aspergillosis (IA), most commonly caused by the filamentous fungus Aspergillus fumigatus, occurs in immune compromised individuals. The ability of A. fumigatus to proliferate in a multitude of environments is hypothesized to contribute to its pathogenicity and virulence. Transcription factors (TF) have long been recognized as critical proteins for fungal pathogenicity, as many are known to play important roles in the transcriptional regulation of pathways implicated in virulence. Such pathways include regulation of conidiation and development, adhesion, nutrient acquisition, adaptation to environmental stress, and interactions with the host immune system among others. In both murine and insect models of IA, TF loss of function in A. fumigatus results in cases of hyper- and hypovirulence as determined through host survival, fungal burden, and immune response analyses. Consequently, the study of specific TFs in A. fumigatus has revealed important insights into mechanisms of pathogenicity and virulence. Although in vitro studies have identified virulence-related functions of specific TFs, the full picture of their in vivo functions remain largely enigmatic and an exciting area of current research. Moreover, the vast majority of TFs remain to be characterized and studied in this important human pathogen. Here in this mini-review we provide an overview of selected TFs in A. fumigatus and their contribution to our understanding of this important human pathogen's pathogenicity and virulence.
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Affiliation(s)
- Katherine M Bultman
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755
| | - Caitlin H Kowalski
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755
| | - Robert A Cramer
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755
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Chen L, Zou G, Wang J, Wang J, Liu R, Jiang Y, Zhao G, Zhou Z. Characterization of the Ca2+-responsive signaling pathway in regulating the expression and secretion of cellulases inTrichoderma reeseiRut-C30. Mol Microbiol 2016; 100:560-75. [DOI: 10.1111/mmi.13334] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/21/2016] [Indexed: 11/28/2022]
Affiliation(s)
- Ling Chen
- Key Laboratory of Synthetic Biology; Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences; Shanghai 200032 China
| | - Gen Zou
- Key Laboratory of Synthetic Biology; Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences; Shanghai 200032 China
| | - Jingzhi Wang
- Key Laboratory of Synthetic Biology; Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences; Shanghai 200032 China
| | - Jin Wang
- Key Laboratory of Synthetic Biology; Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences; Shanghai 200032 China
| | - Rui Liu
- Key Laboratory of Synthetic Biology; Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences; Shanghai 200032 China
| | - Yanping Jiang
- Key Laboratory of Synthetic Biology; Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences; Shanghai 200032 China
| | - Guoping Zhao
- Key Laboratory of Synthetic Biology; Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences; Shanghai 200032 China
| | - Zhihua Zhou
- Key Laboratory of Synthetic Biology; Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences; Shanghai 200032 China
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Muñoz A, Bertuzzi M, Bettgenhaeuser J, Iakobachvili N, Bignell EM, Read ND. Different Stress-Induced Calcium Signatures Are Reported by Aequorin-Mediated Calcium Measurements in Living Cells of Aspergillus fumigatus. PLoS One 2015; 10:e0138008. [PMID: 26402916 PMCID: PMC4581630 DOI: 10.1371/journal.pone.0138008] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 08/24/2015] [Indexed: 11/18/2022] Open
Abstract
Aspergillus fumigatus is an inhaled fungal pathogen of human lungs, the developmental growth of which is reliant upon Ca2+-mediated signalling. Ca2+ signalling has regulatory significance in all eukaryotic cells but how A. fumigatus uses intracellular Ca2+ signals to respond to stresses imposed by the mammalian lung is poorly understood. In this work, A. fumigatus strains derived from the clinical isolate CEA10, and a non-homologous recombination mutant ΔakuBKU80, were engineered to express the bioluminescent Ca2+-reporter aequorin. An aequorin-mediated method for routine Ca2+ measurements during the early stages of colony initiation was successfully developed and dynamic changes in cytosolic free calcium ([Ca2+]c) in response to extracellular stimuli were measured. The response to extracellular challenges (hypo- and hyper-osmotic shock, mechanical perturbation, high extracellular Ca2+, oxidative stress or exposure to human serum) that the fungus might be exposed to during infection, were analysed in living conidial germlings. The 'signatures' of the transient [Ca2+]c responses to extracellular stimuli were found to be dose- and age-dependent. Moreover, Ca2+-signatures associated with each physico-chemical treatment were found to be unique, suggesting the involvement of heterogeneous combinations of Ca2+-signalling components in each stress response. Concordant with the involvement of Ca2+-calmodulin complexes in these Ca2+-mediated responses, the calmodulin inhibitor trifluoperazine (TFP) induced changes in the Ca2+-signatures to all the challenges. The Ca2+-chelator BAPTA potently inhibited the initial responses to most stressors in accordance with a critical role for extracellular Ca2+ in initiating the stress responses.
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Affiliation(s)
- Alberto Muñoz
- Manchester Fungal Infection Group, Institute of Inflammation and Repair, University of Manchester, Manchester, United Kingdom
- Fungal Cell Biology Group, Institute of Cell Biology, University of Edinburgh, Edinburgh, United Kingdom
| | - Margherita Bertuzzi
- Manchester Fungal Infection Group, Institute of Inflammation and Repair, University of Manchester, Manchester, United Kingdom
- Centre for Molecular Bacteriology and Infection, Department of Medicine, Imperial College London, London, United Kingdom
| | - Jan Bettgenhaeuser
- Fungal Cell Biology Group, Institute of Cell Biology, University of Edinburgh, Edinburgh, United Kingdom
| | - Nino Iakobachvili
- Centre for Molecular Bacteriology and Infection, Department of Medicine, Imperial College London, London, United Kingdom
| | - Elaine M. Bignell
- Manchester Fungal Infection Group, Institute of Inflammation and Repair, University of Manchester, Manchester, United Kingdom
- Centre for Molecular Bacteriology and Infection, Department of Medicine, Imperial College London, London, United Kingdom
- * E-mail: (NDR); (EMB)
| | - Nick D. Read
- Manchester Fungal Infection Group, Institute of Inflammation and Repair, University of Manchester, Manchester, United Kingdom
- Fungal Cell Biology Group, Institute of Cell Biology, University of Edinburgh, Edinburgh, United Kingdom
- * E-mail: (NDR); (EMB)
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Xiong D, Wang Y, Tang C, Fang Y, Zou J, Tian C. VdCrz1 is involved in microsclerotia formation and required for full virulence in Verticillium dahliae. Fungal Genet Biol 2015; 82:201-12. [PMID: 26235044 DOI: 10.1016/j.fgb.2015.07.011] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Revised: 07/29/2015] [Accepted: 07/30/2015] [Indexed: 10/23/2022]
Abstract
Calcium signaling plays crucial roles in ion stress tolerance, sporulation and pathogenicity in fungi. Although the signaling pathway mediated by calcineurin and the calcineurin-responsive zinc finger transcription factor Crz1 is well characterized in other fungi, this pathway is not well characterized in the phytopathogenic fungus, Verticillium dahliae. To better understand the role of this calcineurin-dependent transcription factor in V. dahliae, an ortholog of CRZ1, VdCrz1, was identified and characterized functionally. Transcriptional analysis of VdCrz1 and GFP expression driven by the VdCrz1 promoter indicated that VdCrz1 was involved in microsclerotia development. After targeted deletion of VdCrz1, microsclerotia formation and melanin accumulation were impaired. Furthermore, the ΔVdCrz1 mutants were hypersensitive to high concentrations of Ca(2+) and cell wall-perturbing agents, such as sodium dodecyl sulfate. The addition of Mg(2+) to the medium restores the microsclerotia formation in ΔVdCrz1 mutants. The ΔVdCrz1 mutants exhibited delayed Verticillium wilt symptoms on smoke tree. These results suggest that VdCrz1 plays important roles in Ca(2+) signaling, cell wall integrity, microsclerotia development and full virulence in V. dahliae.
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Affiliation(s)
- Dianguang Xiong
- The Key Laboratory for Silviculture and Conservation of Ministry of Education, College of Forestry, Beijing Forestry University, Beijing, China
| | - Yonglin Wang
- The Key Laboratory for Silviculture and Conservation of Ministry of Education, College of Forestry, Beijing Forestry University, Beijing, China.
| | - Chen Tang
- The Key Laboratory for Silviculture and Conservation of Ministry of Education, College of Forestry, Beijing Forestry University, Beijing, China
| | - Yulin Fang
- The Key Laboratory for Silviculture and Conservation of Ministry of Education, College of Forestry, Beijing Forestry University, Beijing, China
| | - Jingyi Zou
- The Key Laboratory for Silviculture and Conservation of Ministry of Education, College of Forestry, Beijing Forestry University, Beijing, China
| | - Chengming Tian
- The Key Laboratory for Silviculture and Conservation of Ministry of Education, College of Forestry, Beijing Forestry University, Beijing, China.
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de Castro PA, Chen C, de Almeida RSC, Freitas FZ, Bertolini MC, Morais ER, Brown NA, Ramalho LNZ, Hagiwara D, Mitchell TK, Goldman GH. ChIP-seq reveals a role for CrzA in the Aspergillus fumigatus high-osmolarity glycerol response (HOG) signalling pathway. Mol Microbiol 2014; 94:655-74. [PMID: 25196896 DOI: 10.1111/mmi.12785] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/03/2014] [Indexed: 12/28/2022]
Abstract
Aspergillus fumigatus is an opportunistic pathogen and allergen of mammals. Calcium signalling is essential for A. fumigatus pathogenicity and is regulated by the CrzA transcription factor. We used ChIP-seq (Chromatin Immunoprecipitation DNA sequencing) to explore CrzA gene targets in A. fumigatus. In total, 165 potential binding peaks including 102 directly regulated genes were identified, resulting in the prediction of the A[GT][CG]CA[AC][AG] CrzA-binding motif. The 102 CrzA putatively regulated genes exhibited a diverse array of functions. The phkB (Afu3g12530) histidine kinase and the sskB (Afu1g10940) MAP kinase kinase kinase of the HOG (high-osmolarity glycerol response) pathway were regulated by CrzA. Several members of the two-component system (TCS) and the HOG pathway were more sensitive to calcium. CrzA::GFP was translocated to the nucleus upon osmotic stress. CrzA is important for the phosphorylation of the SakA MAPK in response to osmotic shock. The ΔsskB was more sensitive to CaCl2 , NaCl, and paraquat stress, while being avirulent in a murine model of invasive pulmonary aspergillosis. The presence of CaCl2 and osmotic stresses resulted in synergistic inhibition of ΔcrzA and ΔsskB growth. These results suggest there is a genetic interaction between the A. fumigatus calcineurin-CrzA and HOG pathway that is essential for full virulence.
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Affiliation(s)
- Patrícia A de Castro
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
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de Castro PA, Chiaratto J, Winkelströter LK, Bom VLP, Ramalho LNZ, Goldman MHS, Brown NA, Goldman GH. The involvement of the Mid1/Cch1/Yvc1 calcium channels in Aspergillus fumigatus virulence. PLoS One 2014; 9:e103957. [PMID: 25083783 PMCID: PMC4118995 DOI: 10.1371/journal.pone.0103957] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Accepted: 07/03/2014] [Indexed: 11/30/2022] Open
Abstract
Aspergillus fumigatus is a major opportunistic pathogen and allergen of mammals. Calcium homeostasis and signaling is essential for numerous biological processes and also influences A. fumigatus pathogenicity. The presented study characterized the function of the A. fumigatus homologues of three Saccharomyces cerevisiae calcium channels, voltage-gated Cch1, stretch-activated Mid1 and vacuolar Yvc1. The A. fumigatus calcium channels cchA, midA and yvcA were regulated at transcriptional level by increased calcium levels. The YvcA::GFP fusion protein localized to the vacuoles. Both ΔcchA and ΔmidA mutant strains showed reduced radial growth rate in nutrient-poor minimal media. Interestingly, this growth defect in the ΔcchA strain was rescued by the exogenous addition of CaCl2. The ΔcchA, ΔmidA, and ΔcchA ΔmidA strains were also sensitive to the oxidative stress inducer, paraquat. Restriction of external Ca2+ through the addition of the Ca2+-chelator EGTA impacted upon the growth of the ΔcchA and ΔmidA strains. All the A. fumigatus ΔcchA, ΔmidA, and ΔyvcA strains demonstrated attenuated virulence in a neutropenic murine model of invasive pulmonary aspergillosis. Infection with the parental strain resulted in a 100% mortality rate at 15 days post-infection, while the mortality rate of the ΔcchA, ΔmidA, and ΔyvcA strains after 15 days post-infection was only 25%. Collectively, this investigation strongly indicates that CchA, MidA, and YvcA play a role in A. fumigatus calcium homeostasis and virulence.
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Affiliation(s)
- Patrícia Alves de Castro
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Jéssica Chiaratto
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Lizziane K. Winkelströter
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Vinícius Leite Pedro Bom
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | | | - Maria Helena S. Goldman
- Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Neil Andrew Brown
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Gustavo H. Goldman
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
- National Laboratory of Science and Technology of Bioethanol (CTBE), Campinas, Brazil
- * E-mail:
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Xu YN, Xia XX, Zhong JJ. Induction of ganoderic acid biosynthesis by Mn2+ in static liquid cultivation of Ganoderma lucidum. Biotechnol Bioeng 2014; 111:2358-65. [PMID: 24870062 DOI: 10.1002/bit.25288] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Revised: 05/05/2014] [Accepted: 05/06/2014] [Indexed: 11/07/2022]
Abstract
Metal ions affect cell physiology and metabolism significantly, but the role of Mn(2+) in the secondary metabolism of mushrooms is yet unclear. In static liquid cultivation of Ganoderma lucidum for producing antitumor ganoderic acids (GAs), the Mn(2+) addition was performed. Addition of 10 mM Mn(2+) at the start of the static liquid cultivation resulted in 2.2-fold improvement of total GAs production. The expression levels of GA biosynthetic and Ca(2+) sensors' genes were up-regulated with Mn(2+) induction while down-regulated by adding cyclosporin A (calcineurin inhibitor), suggesting that higher GA production might result from calcineurin signal regulation. Intracellular Ca(2+) imaging and calcineurin inhibitor study revealed that addition of Mn(2+) led to Ca(2+) influx from medium to the cells to trigger calcineurin signals. Mn(2+) addition was therefore an efficient induction strategy for improving GAs production, whose regulation mechanism was via calcineurin signaling transduction.
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Affiliation(s)
- Yi-Ning Xu
- State Key Laboratory of Microbial Metabolism and Laboratory of Molecular Biochemical Engineering, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 800 Dong-Chuan Road, Shanghai, 200240, China
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Abstract
Calcium ions are ubiquitous intracellular messengers. An increase in the cytosolic Ca(2+) concentration activates many proteins, including calmodulin and the Ca(2+)/calmodulin-dependent protein phosphatase calcineurin. The phosphatase is conserved from yeast to humans (except in plants), and many target proteins of calcineurin have been identified. The most prominent and best-investigated targets, however, are the transcription factors NFAT (nuclear factor of activated T cells) in mammals and Crz1 (calcineurin-responsive zinc finger 1) in yeast. In recent years, many orthologues of Crz1 have been identified and characterized in various species of fungi, amoebae, and other lower eukaryotes. It has been shown that the functions of calcineurin-Crz1 signaling, ranging from ion homeostasis through cell wall biogenesis to the building of filamentous structures, are conserved in the different organisms. Furthermore, frequency-modulated gene expression through Crz1 has been discovered as a striking new mechanism by which cells can coordinate their response to a signal. In this review, I focus on the latest findings concerning calcineurin-Crz1 signaling in fungi, amoebae and other lower eukaryotes. I discuss the potential of Crz1 and its orthologues as putative drug targets, and I also discuss possible parallels with calcineurin-NFAT signaling in mammals.
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Schaenman JM, Khuu T, Kubak BM. Fungi as Eukaryotes: Understanding the Antifungal Effects of Immunosuppressive Drugs. CURRENT FUNGAL INFECTION REPORTS 2014. [DOI: 10.1007/s12281-013-0169-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Genetic bypass of Aspergillus nidulans crzA function in calcium homeostasis. G3-GENES GENOMES GENETICS 2013; 3:1129-41. [PMID: 23665873 PMCID: PMC3704241 DOI: 10.1534/g3.113.005983] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
After dephosphorylation by the phosphatase calcineurin, the fungal transcription factor CrzA enters the nucleus and activates the transcription of genes responsible for calcium homeostasis and many other calcium-regulated activities. A lack of CrzA confers calcium-sensitivity to the filamentous fungus Aspergillus nidulans. To further understand calcium signaling in filamentous fungi and to identify genes that interact genetically with CrzA, we selected for mutations that were able to suppress crzAΔ calcium intolerance and identified three genes. Through genetic mapping, gene sequencing, and mutant rescue, we were able to identify these as cnaB (encoding the calcineurin regulatory subunit), folA (encoding an enzyme involved in folic acid biosynthesis, dihydroneopterin aldolase), and scrC (suppression of crzA-, encoding a hypothetical protein). By using a calcium indicator, Fluo-3, we were able to determine that the wild-type and the suppressor strains were either able to regulate intracellular calcium levels or were able to take up and or store calcium correctly. The increased expression of calcium transporters, pmcA and/or pmcB, in suppressor mutants possibly enabled tolerance to high levels of calcium. Our results suggest that a cnaB suppressor mutation confers calcium tolerance to crzAΔ strains through restoration of calcium homeostasis. These results stress that in A. nidulans there are calcineurin-dependent and CrzA-independent pathways. In addition, it is possible that CrzA is able to contribute to the modulation of folic acid biosynthesis.
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Affiliation(s)
| | | | - John E. Linz
- Department of Food Science and Human Nutrition,
- Department of Microbiology and Molecular Genetics,
- National Food Safety and Toxicology Center,
- Center for Integrative Toxicology, Michigan State University, East Lansing, Michigan 48824;
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Xu YN, Xia XX, Zhong JJ. Induced effect of Na+on ganoderic acid biosynthesis in static liquid culture ofGanoderma lucidumvia calcineurin signal transduction. Biotechnol Bioeng 2013; 110:1913-23. [DOI: 10.1002/bit.24852] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2012] [Revised: 01/11/2013] [Accepted: 01/14/2013] [Indexed: 11/08/2022]
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The Ca2+/calcineurin-dependent signaling pathway in the gray mold Botrytis cinerea: the role of calcipressin in modulating calcineurin activity. PLoS One 2012; 7:e41761. [PMID: 22844520 PMCID: PMC3402410 DOI: 10.1371/journal.pone.0041761] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2012] [Accepted: 06/25/2012] [Indexed: 12/31/2022] Open
Abstract
In the gray mold fungus Botrytis cinerea the Gα subunit Bcg1 of a heterotrimeric G protein is an upstream activator of the Ca2+/calmodulin-dependent phosphatase calcineurin. In this study we focused on the functional characterization of the catalytic subunit of calcineurin (BcCnA) and its putative regulator calcipressin (BcRcn1). We deleted the genes encoding both proteins to examine their role concerning growth, differentiation and virulence. The ΔbccnA mutant shows a severe growth defect, does not produce conidia and is avirulent, while the loss of BcRcn1 caused retardation of hyphal growth and delayed infection of host plants, but had no impact on conidiation and sclerotia formation. Expression of several calcineurin-dependent genes and bccnA itself is positively affected by BcRcn1. Complementation of the Δbcrcn1 mutant with a GFP-BcRcn1 fusion construct revealed that BcRcn1 is localized in the cytoplasm and accumulates around the nuclei. Furthermore, we showed that BcCnA physically interacts with BcRcn1 and the regulatory subunit of calcineurin, BcCnB. We investigated the impact of several protein domains characteristic for modulation and activation of BcCnA via BcRcn1, such as the phosphorylation sites and the calcineurin-docking site, by physical interaction studies between BcCnA and wild-type and mutated copies of BcRcn1. Based on the observed phenotypes we conclude that BcRcn1 acts as a positive modulator of BcCnA and the Ca2+/calcineurin-mediated signal transduction in B. cinerea, and that both proteins regulate fungal development and virulence.
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Dinamarco TM, Freitas FZ, Almeida RS, Brown NA, dos Reis TF, Ramalho LNZ, Savoldi M, Goldman MHS, Bertolini MC, Goldman GH. Functional characterization of an Aspergillus fumigatus calcium transporter (PmcA) that is essential for fungal infection. PLoS One 2012; 7:e37591. [PMID: 22649543 PMCID: PMC3359301 DOI: 10.1371/journal.pone.0037591] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2012] [Accepted: 04/22/2012] [Indexed: 02/01/2023] Open
Abstract
Aspergillus fumigatus is a primary and opportunistic pathogen, as well as a major allergen, of mammals. The Ca(+2)-calcineurin pathway affects virulence, morphogenesis and antifungal drug action in A. fumigatus. Here, we investigated three components of the A. fumigatus Ca(+2)-calcineurin pathway, pmcA,-B, and -C, which encode calcium transporters. We demonstrated that CrzA can directly control the mRNA accumulation of the pmcA-C genes by binding to their promoter regions. CrzA-binding experiments suggested that the 5'-CACAGCCAC-3' and 5'-CCCTGCCCC-3' sequences upstream of pmcA and pmcC genes, respectively, are possible calcineurin-dependent response elements (CDREs)-like consensus motifs. Null mutants were constructed for pmcA and -B and a conditional mutant for pmcC demonstrating pmcC is an essential gene. The ΔpmcA and ΔpmcB mutants were more sensitive to calcium and resistant to manganese and cyclosporin was able to modulate the sensitivity or resistance of these mutants to these salts, supporting the interaction between calcineurin and the function of these transporters. The pmcA-C genes have decreased mRNA abundance into the alveoli in the ΔcalA and ΔcrzA mutant strains. However, only the A. fumigatus ΔpmcA was avirulent in the murine model of invasive pulmonary aspergillosis.
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Affiliation(s)
- Taísa Magnani Dinamarco
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | | | - Ricardo S. Almeida
- Department of Microbiology, University of Londrina, Londrina, Paraná, Brazil
| | - Neil Andrew Brown
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - Thaila Fernanda dos Reis
- 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
| | - 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
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Suh MJ, Fedorova ND, Cagas SE, Hastings S, Fleischmann RD, Peterson SN, Perlin DS, Nierman WC, Pieper R, Momany M. Development stage-specific proteomic profiling uncovers small, lineage specific proteins most abundant in the Aspergillus Fumigatus conidial proteome. Proteome Sci 2012; 10:30. [PMID: 22545825 PMCID: PMC3424117 DOI: 10.1186/1477-5956-10-30] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2011] [Accepted: 04/30/2012] [Indexed: 11/14/2022] Open
Abstract
Background The pathogenic mold Aspergillus fumigatus is the most frequent infectious cause of death in severely immunocompromised individuals such as leukemia and bone marrow transplant patients. Germination of inhaled conidia (asexual spores) in the host is critical for the initiation of infection, but little is known about the underlying mechanisms of this process. Results To gain insights into early germination events and facilitate the identification of potential stage-specific biomarkers and vaccine candidates, we have used quantitative shotgun proteomics to elucidate patterns of protein abundance changes during early fungal development. Four different stages were examined: dormant conidia, isotropically expanding conidia, hyphae in which germ tube emergence has just begun, and pre-septation hyphae. To enrich for glycan-linked cell wall proteins we used an alkaline cell extraction method. Shotgun proteomic resulted in the identification of 375 unique gene products with high confidence, with no evidence for enrichment of cell wall-immobilized and secreted proteins. The most interesting discovery was the identification of 52 proteins enriched in dormant conidia including 28 proteins that have never been detected in the A. fumigatus conidial proteome such as signaling protein Pil1, chaperones BipA and calnexin, and transcription factor HapB. Additionally we found many small, Aspergillus specific proteins of unknown function including 17 hypothetical proteins. Thus, the most abundant protein, Grg1 (AFUA_5G14210), was also one of the smallest proteins detected in this study (M.W. 7,367). Among previously characterized proteins were melanin pigment and pseurotin A biosynthesis enzymes, histones H3 and H4.1, and other proteins involved in conidiation and response to oxidative or hypoxic stress. In contrast, expanding conidia, hyphae with early germ tubes, and pre-septation hyphae samples were enriched for proteins responsible for housekeeping functions, particularly translation, respiratory metabolism, amino acid and carbohydrate biosynthesis, and the tricarboxylic acid cycle. Conclusions The observed temporal expression patterns suggest that the A. fumigatus conidia are dominated by small, lineage-specific proteins. Some of them may play key roles in host-pathogen interactions, signal transduction during conidial germination, or survival in hostile environments.
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Affiliation(s)
- Moo-Jin Suh
- The J. Craig Venter Institute, 9704 Medical Center Drive, Rockville, MD, USA
| | - Natalie D Fedorova
- The J. Craig Venter Institute, 9704 Medical Center Drive, Rockville, MD, USA
| | - Steven E Cagas
- University of Medicine and Dentistry of New Jersey, Newark, NJ, USA
| | - Susan Hastings
- Department of Plant Biology, University of Georgia, Athens, GA, USA
| | | | - Scott N Peterson
- The J. Craig Venter Institute, 9704 Medical Center Drive, Rockville, MD, USA
| | - David S Perlin
- University of Medicine and Dentistry of New Jersey, Newark, NJ, USA
| | - William C Nierman
- The J. Craig Venter Institute, 9704 Medical Center Drive, Rockville, MD, USA
| | - Rembert Pieper
- The J. Craig Venter Institute, 9704 Medical Center Drive, Rockville, MD, USA
| | - Michelle Momany
- Department of Plant Biology, University of Georgia, Athens, GA, USA
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Hagag S, Kubitschek-Barreira P, Neves GWP, Amar D, Nierman W, Shalit I, Shamir R, Lopes-Bezerra L, Osherov N. Transcriptional and proteomic analysis of the Aspergillus fumigatus ΔprtT protease-deficient mutant. PLoS One 2012; 7:e33604. [PMID: 22514608 PMCID: PMC3326020 DOI: 10.1371/journal.pone.0033604] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2011] [Accepted: 02/13/2012] [Indexed: 01/21/2023] Open
Abstract
Aspergillus fumigatus is the most common opportunistic mold pathogen of humans, infecting immunocompromised patients. The fungus invades the lungs and other organs, causing severe damage. Penetration of the pulmonary epithelium is a key step in the infectious process. A. fumigatus produces extracellular proteases to degrade the host structural barriers. The A. fumigatus transcription factor PrtT controls the expression of multiple secreted proteases. PrtT shows similarity to the fungal Gal4-type Zn(2)-Cys(6) DNA-binding domain of several transcription factors. In this work, we further investigate the function of this transcription factor by performing a transcriptional and a proteomic analysis of the ΔprtT mutant. Unexpectedly, microarray analysis revealed that in addition to the expected decrease in protease expression, expression of genes involved in iron uptake and ergosterol synthesis was dramatically decreased in the ΔprtT mutant. A second finding of interest is that deletion of prtT resulted in the upregulation of four secondary metabolite clusters, including genes for the biosynthesis of toxic pseurotin A. Proteomic analysis identified reduced levels of three secreted proteases (ALP1 protease, TppA, AFUA_2G01250) and increased levels of three secreted polysaccharide-degrading enzymes in the ΔprtT mutant possibly in response to its inability to derive sufficient nourishment from protein breakdown. This report highlights the complexity of gene regulation by PrtT, and suggests a potential novel link between the regulation of protease secretion and the control of iron uptake, ergosterol biosynthesis and secondary metabolite production in A. fumigatus.
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Affiliation(s)
- Shelly Hagag
- Department of Clinical Microbiology and Immunology, Sackler School of Medicine Ramat-Aviv, Tel-Aviv, Israel
| | - Paula Kubitschek-Barreira
- Department of Cellular Biology, The Roberto Alcantara Gomes Institute of Biology, University of Estado Rio de Janeiro, Brazil
| | - Gabriela W. P. Neves
- Department of Cellular Biology, The Roberto Alcantara Gomes Institute of Biology, University of Estado Rio de Janeiro, Brazil
| | - David Amar
- Department of Computer Science, Tel-Aviv University, Ramat-Aviv, Tel-Aviv, Israel
| | - William Nierman
- The J. CraigVenter Institute, Rockville, Maryland, United States of America
| | - Itamar Shalit
- Sackler School of Medicine, Ramat Aviv, Tel-Aviv, Israel
| | - Ron Shamir
- Department of Computer Science, Tel-Aviv University, Ramat-Aviv, Tel-Aviv, Israel
| | - Leila Lopes-Bezerra
- Department of Cellular Biology, The Roberto Alcantara Gomes Institute of Biology, University of Estado Rio de Janeiro, Brazil
| | - Nir Osherov
- Department of Clinical Microbiology and Immunology, Sackler School of Medicine Ramat-Aviv, Tel-Aviv, Israel
- * E-mail:
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45
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Molecular characterization of the putative transcription factor SebA involved in virulence in Aspergillus fumigatus. EUKARYOTIC CELL 2012; 11:518-31. [PMID: 22345349 DOI: 10.1128/ec.00016-12] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Aspergillus fumigatus is a major opportunistic pathogen and allergen of mammals. Nutrient sensing and acquisition mechanisms, as well as the capability to cope with different stressing conditions, are essential for A. fumigatus virulence and survival in the mammalian host. This study characterized the A. fumigatus SebA transcription factor, which is the putative homologue of the factor encoded by Trichoderma atroviride seb1. The ΔsebA mutant demonstrated reduced growth in the presence of paraquat, hydrogen peroxide, CaCl2, and poor nutritional conditions, while viability associated with sebA was also affected by heat shock exposure. Accordingly, SebA::GFP (SebA::green fluorescent protein) was shown to accumulate in the nucleus upon exposure to oxidative stress and heat shock conditions. In addition, genes involved in either the oxidative stress or heat shock response had reduced transcription in the ΔsebA mutant. The A. fumigatus ΔsebA strain was attenuated in virulence in a murine model of invasive pulmonary aspergillosis. Furthermore, killing of the ΔsebA mutant by murine alveolar macrophages was increased compared to killing of the wild-type strain. A. fumigatus SebA plays a complex role, contributing to several stress tolerance pathways and growth under poor nutritional conditions, and seems to be integrated into different stress responses.
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46
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Impacts of calcium signal transduction on the fermentation production of antitumor ganoderic acids by medicinal mushroom Ganoderma lucidum. Biotechnol Adv 2011; 30:1301-8. [PMID: 22036615 DOI: 10.1016/j.biotechadv.2011.10.001] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2011] [Revised: 10/05/2011] [Accepted: 10/11/2011] [Indexed: 11/24/2022]
Abstract
Recently signal transduction engineering of secondary metabolism is receiving great interest as a powerful tool towards efficient production of valuable secondary metabolites. This work found that the calcineurin-signal transduction was significant to triterpene biosynthesis by higher fungus (mushroom). Addition of calcium ion (at 10mM) to static liquid cultures of Ganoderma lucidum, a famous traditional medicinal mushroom, was proved as a useful strategy to enhance the production of antitumor ganoderic acids (GAs), which resulted in 3.7-, 2.6-, 4.5-, 3.2- and 3.8-fold improvement of total GAs, individual GA-Mk, -T, -S, and -Me, respectively. Experiments using Ca2+ sensor inhibitors indicated the involvement of calcineurin signal in regulating GAs biosynthesis. Quantitative gene transcription analysis revealed that the expression levels of genes of GAs biosynthesis and Ca2+ sensor were up-regulated with calcium addition while down-regulated under the inhibitors addition, suggesting that higher GAs production may be resulted from higher expressions of those genes. Based on the results obtained, a possible model on the effect of external calcium ion on the GAs biosynthesis via calcineurin signal transduction pathway was proposed.
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Park YD, Williamson PR. 'Popping the clutch': novel mechanisms regulating sexual development in Cryptococcus neoformans. Mycopathologia 2011; 173:359-66. [PMID: 21912854 DOI: 10.1007/s11046-011-9464-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Accepted: 08/08/2011] [Indexed: 10/17/2022]
Abstract
Sexual reproduction in fungal pathogens such as Cryptococcus provides natural selection and adaptation of the organisms to environmental conditions by allowing beneficial mutations to spread. However, successful mating in these fungi requires a time-critical induction of signaling pheromones when appropriate partners become available. Recently, it has been shown that the fungus uses the transcriptional equivalent of the racing technique: 'popping the clutch'-pushing in the clutch pedal, putting the car in gear, revving with the gas pedal, and then dropping the clutch pedal to accelerate rapidly. In the same way, Cryptococcus during vegetative growth constitutively matches a high rate of pheromone synthesis with a high rate of degradation to produce repressed levels of transcript. Then, when mating is required, the fungus drops the degradative machinery, resulting in a rapid induction of the pheromone. Pairing with this novel regulatory cycle is a host of mitogen-activated protein kinase cascades, cyclic AMP-dependent, and calcium-calcineurin signaling pathways that maintain these high rates of pheromone synthesis and prime downstream pathways for an effective mating response. The intersection of a number of virulence-associated traits with sexual development such as the synthesis of an immune-disruptive laccase as well as a protective polysaccharide capsule makes these rapid regulatory strategies a formidable foe in the battle against human disease.
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Affiliation(s)
- Yoon-Dong Park
- National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
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Kmetzsch L, Staats CC, Rodrigues ML, Schrank A, Vainstein MH. Calcium signaling components in the human pathogen: Cryptococcus neoformans. Commun Integr Biol 2011; 4:186-7. [PMID: 21655435 DOI: 10.4161/cib.4.2.14271] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2010] [Accepted: 11/22/2010] [Indexed: 11/19/2022] Open
Abstract
Calcium signaling through calmodulin and the phosphatase calcineurin are required for key events of the biology of the human pathogen Cryptococcus neoformans, including mating, morphogenesis, growth at 37°C and virulence. In a recent work we described the functional characterization of a new component of this calcium signaling network: the vacuolar calcium exchanger Vcx1. This transporter is involved in calcium tolerance and virulence in C. neoformans. Two other uncharacterized calcium transporters which are putative orthologs of Saccharomyces cerevisiae PMC1 (a vacuolar calcium ATPase) and PMR1 (a Golgi calcium ATPase) are also functional in C. neoformans. No ortholog of CRZ1, the target of calcineurin in other fungi, has been identified in C. neoformans, indicating a high complexity in cryptococcal calcium-related pathways. Future studies are necessary for the complete understanding of calcium signaling regulation in C. neoformans.
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Affiliation(s)
- Livia Kmetzsch
- Centro de Biotecnologia; Universidade Federal do Rio Grande do Sul; Porto Alegre, RS, Brazil
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What makes Aspergillus fumigatus a successful pathogen? Genes and molecules involved in invasive aspergillosis. Rev Iberoam Micol 2010; 27:155-82. [PMID: 20974273 DOI: 10.1016/j.riam.2010.10.003] [Citation(s) in RCA: 267] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2010] [Revised: 10/06/2010] [Accepted: 10/07/2010] [Indexed: 11/21/2022] Open
Abstract
Aspergillus fumigatus is an opportunistic pathogen that causes 90% of invasive aspergillosis (IA) due to Aspergillus genus, with a 50-95% mortality rate. It has been postulated that certain virulence factors are characteristic of A. fumigatus, but the "non-classical" virulence factors seem to be highly variable. Overall, published studies have demonstrated that the virulence of this fungus is multifactorial, associated with its structure, its capacity for growth and adaptation to stress conditions, its mechanisms for evading the immune system and its ability to cause damage to the host. In this review we intend to give a general overview of the genes and molecules involved in the development of IA. The thermotolerance section focuses on five genes related with the capacity of the fungus to grow at temperatures above 30°C (thtA, cgrA, afpmt1, kre2/afmnt1, and hsp1/asp f 12). The following sections discuss molecules and genes related to interaction with the host and with the immune responses. These sections include β-glucan, α-glucan, chitin, galactomannan, galactomannoproteins (afmp1/asp f 17 and afmp2), hydrophobins (rodA/hyp1 and rodB), DHN-melanin, their respective synthases (fks1, rho1-4, ags1-3, chsA-G, och1-4, mnn9, van1, anp1, glfA, pksP/alb1, arp1, arp2, abr1, abr2, and ayg1), and modifying enzymes (gel1-7, bgt1, eng1, ecm33, afpigA, afpmt1-2, afpmt4, kre2/afmnt1, afmnt2-3, afcwh41 and pmi); several enzymes related to oxidative stress protection such as catalases (catA, cat1/catB, cat2/katG, catC, and catE), superoxide dismutases (sod1, sod2, sod3/asp f 6, and sod4), fatty acid oxygenases (ppoA-C), glutathione tranferases (gstA-E), and others (afyap1, skn7, and pes1); and efflux transporters (mdr1-4, atrF, abcA-E, and msfA-E). In addition, this review considers toxins and related genes, such as a diffusible toxic substance from conidia, gliotoxin (gliP and gliZ), mitogillin (res/mitF/asp f 1), hemolysin (aspHS), festuclavine and fumigaclavine A-C, fumitremorgin A-C, verruculogen, fumagillin, helvolic acid, aflatoxin B1 and G1, and laeA. Two sections cover genes and molecules related with nutrient uptake, signaling and metabolic regulations involved in virulence, including enzymes, such as serine proteases (alp/asp f 13, alp2, and asp f 18), metalloproteases (mep/asp f 5, mepB, and mep20), aspartic proteases (pep/asp f 10, pep2, and ctsD), dipeptidylpeptidases (dppIV and dppV), and phospholipases (plb1-3 and phospholipase C); siderophores and iron acquisition (sidA-G, sreA, ftrA, fetC, mirB-C, and amcA); zinc acquisition (zrfA-H, zafA, and pacC); amino acid biosynthesis, nitrogen uptake, and cross-pathways control (areA, rhbA, mcsA, lysF, cpcA/gcn4p, and cpcC/gcn2p); general biosynthetic pathway (pyrG, hcsA, and pabaA), trehalose biosynthesis (tpsA and tpsB), and other regulation pathways such as those of the MAP kinases (sakA/hogA, mpkA-C, ste7, pbs2, mkk2, steC/ste11, bck1, ssk2, and sho1), G-proteins (gpaA, sfaD, and cpgA), cAMP-PKA signaling (acyA, gpaB, pkaC1, and pkaR), His kinases (fos1 and tcsB), Ca(2+) signaling (calA/cnaA, crzA, gprC and gprD), and Ras family (rasA, rasB, and rhbA), and others (ace2, medA, and srbA). Finally, we also comment on the effect of A. fumigatus allergens (Asp f 1-Asp f 34) on IA. The data gathered generate a complex puzzle, the pieces representing virulence factors or the different activities of the fungus, and these need to be arranged to obtain a comprehensive vision of the virulence of A. fumigatus. The most recent gene expression studies using DNA-microarrays may be help us to understand this complex virulence, and to detect targets to develop rapid diagnostic methods and new antifungal agents.
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Kim S, Hu J, Oh Y, Park J, Choi J, Lee YH, Dean RA, Mitchell TK. Combining ChIP-chip and expression profiling to model the MoCRZ1 mediated circuit for Ca/calcineurin signaling in the rice blast fungus. PLoS Pathog 2010; 6:e1000909. [PMID: 20502632 PMCID: PMC2873923 DOI: 10.1371/journal.ppat.1000909] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2009] [Accepted: 04/14/2010] [Indexed: 01/22/2023] Open
Abstract
Significant progress has been made in defining the central signaling networks in many organisms, but collectively we know little about the downstream targets of these networks and the genes they regulate. To reconstruct the regulatory circuit of calcineurin signal transduction via MoCRZ1, a Magnaporthe oryzae C2H2 transcription factor activated by calcineurin dephosphorylation, we used a combined approach of chromatin immunoprecipitation - chip (ChIP-chip), coupled with microarray expression studies. One hundred forty genes were identified as being both a direct target of MoCRZ1 and having expression concurrently differentially regulated in a calcium/calcineurin/MoCRZ1 dependent manner. Highly represented were genes involved in calcium signaling, small molecule transport, ion homeostasis, cell wall synthesis/maintenance, and fungal virulence. Of particular note, genes involved in vesicle mediated secretion necessary for establishing host associations, were also found. MoCRZ1 itself was a target, suggesting a previously unreported autoregulation control point. The data also implicated a previously unreported feedback regulation mechanism of calcineurin activity. We propose that calcium/calcineurin regulated signal transduction circuits controlling development and pathogenicity manifest through multiple layers of regulation. We present results from the ChIP-chip and expression analysis along with a refined model of calcium/calcineurin signaling in this important plant pathogen. All organisms have the innate ability to perceive their environment and respond to it, largely through controlling gene expression. Tailored specificity of a response is primarily achieved through signal cascades involving unique receptors, downstream transcription factors (proteins that bind to DNA to regulate gene expression), and the genes these transcription factors regulate. For fungal plant pathogens, signal transduction cascades are involved in perception of hosts, transgression of physical barriers, suppression or elicitation of host defenses, in vivo nutrient acquisition, and completion of their life cycle. We know that the Ca2+/calcineurin signaling pathway is a central conduit regulating these aspects of the life cycle for fungal pathogens of plants and animals. In this study, we used advanced ChIP-chip and microarray gene expression technologies to identify the genes that the Ca2+/calcineurin responsive transcription factor MoCRZ1 directly binds to and regulates the expression of. Our findings show conservations and divergence in this pathway within the fungal kingdom. It also identifies points of control in the pathway that were previously unidentified. Most importantly, this study implicates this pathway in the establishment of host associations and virulence for the causal agent of rice blast disease, Magnaporthe oryzae, the most important disease of rice worldwide.
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Affiliation(s)
- Soonok Kim
- Department of Plant Pathology, The Ohio State University, Columbus, Ohio, United States of America
| | - Jinnan Hu
- Department of Plant Pathology, The Ohio State University, Columbus, Ohio, United States of America
| | - Yeonyee Oh
- Center for Integrated Fungal Research, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Jongsun Park
- Department of Agricultural Biotechnology, Center for Agricultural Biomaterials, Center for Fungal Genetic Resources, and Center for Fungal Pathogenesis, Seoul National University, Seoul, Korea
| | - Jinhee Choi
- Department of Agricultural Biotechnology, Center for Agricultural Biomaterials, Center for Fungal Genetic Resources, and Center for Fungal Pathogenesis, Seoul National University, Seoul, Korea
| | - Yong-Hwan Lee
- Department of Agricultural Biotechnology, Center for Agricultural Biomaterials, Center for Fungal Genetic Resources, and Center for Fungal Pathogenesis, Seoul National University, Seoul, Korea
| | - Ralph A. Dean
- Center for Integrated Fungal Research, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Thomas K. Mitchell
- Department of Plant Pathology, The Ohio State University, Columbus, Ohio, United States of America
- * E-mail:
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