1
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Jiang L, Xu H, Gu Y, Wei L. A glycosylated Phr1 protein is induced by calcium stress and its expression is positively controlled by the calcium/calcineurin signaling transcription factor Crz1 in Candida albicans. Cell Commun Signal 2023; 21:237. [PMID: 37723578 PMCID: PMC10506259 DOI: 10.1186/s12964-023-01224-y] [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: 03/13/2023] [Accepted: 07/12/2023] [Indexed: 09/20/2023] Open
Abstract
As one of the most important human fungal pathogens, Candida albicans senses and adapts to host niches with different pH values through the pH-responsive Rim101 pathway. Its transcription factor Rim101 activates the expression of alkaline pH-induced genes including PHR1 that encodes a glycosylphosphatidylinsitol-anchored β(1,3)-glucanosyltransferase critical for hyphal wall formation. The calcium/calcineurin signaling pathway is mediated by the transcription factor Crz1 in yeasts and other lower eukaryotes. Here we report that deletion of PHR1 leads to calcium sensitivity of C. albicans cells. In addition, expression of Phr1 is induced by calcium stress and under the control of Crz1 in C. albicans. EMSA assay demonstrates that Crz1 binds to one CDRE element in the PHR1 promoter. Alkaline treatment induces two species of glycosylated Phr1 proteins with different degrees of glycosylation, which is independent of Crz1. In contrast, only one species of Phr1 protein with a low degree of glycosylation is induced by calcium stress in a Crz1-dependent fashion. Therefore, we have provided an evidence that regulation of cell wall remodeling is integrated through differential degrees of Phr1 glycosylation by both the pH-regulated Rim101 pathway and the calcium/calcineurin signaling pathway in C. albicans. Video Abstract.
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Affiliation(s)
- Linghuo Jiang
- Laboratory of Yeast Biology and Fermentation Technology, Institute of Biological Sciences and Technology, Guangxi Academy of Sciences, Nanning, 530007, Guangxi, China.
| | - Huihui Xu
- Department of Food Science, School of Agricultural Engineering and Food Science, Shandong University of Technology, Zibo, 255000, China
| | - Yiying Gu
- Laboratory of Yeast Biology and Fermentation Technology, Institute of Biological Sciences and Technology, Guangxi Academy of Sciences, Nanning, 530007, Guangxi, China
| | - Liudan Wei
- Laboratory of Yeast Biology and Fermentation Technology, Institute of Biological Sciences and Technology, Guangxi Academy of Sciences, Nanning, 530007, Guangxi, China
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2
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Chadwick BJ, Ross BE, Lin X. Molecular Dissection of Crz1 and Its Dynamic Subcellular Localization in Cryptococcus neoformans. J Fungi (Basel) 2023; 9:jof9020252. [PMID: 36836365 PMCID: PMC9963361 DOI: 10.3390/jof9020252] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 02/01/2023] [Accepted: 02/08/2023] [Indexed: 02/17/2023] Open
Abstract
Across lower eukaryotes, the transcription factor Crz1 is dephosphorylated by calcineurin, which facilitates Crz1 translocation to the nucleus to regulate gene expression. In the fungal pathogen Cryptococcus neoformans, calcineurin-Crz1 signaling maintains calcium homeostasis, thermotolerance, cell wall integrity, and morphogenesis. How Crz1 distinguishes different stressors and differentially regulates cellular responses is poorly understood. Through monitoring Crz1 subcellular localization over time, we found that Crz1 transiently localizes to granules after exposure to high temperature or calcium. These granules also host the phosphatase calcineurin and Pub1, a ribonucleoprotein stress granule marker, suggesting a role of stress granules in modulating calcineurin-Crz1 signaling. Additionally, we constructed and analyzed an array of Crz1 truncation mutants. We identified the intrinsically disordered regions in Crz1 contribute to proper stress granule localization, nuclear localization, and function. Our results provide the groundwork for further determination of the mechanisms behind the complex regulation of Crz1.
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Affiliation(s)
| | | | - Xiaorong Lin
- Department of Plant Biology, University of Georgia, Athens, GA 30602, USA
- Department of Microbiology, University of Georgia, Athens, GA 30602, USA
- Correspondence:
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3
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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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4
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Wagner AS, Lumsdaine SW, Mangrum MM, King AE, Hancock TJ, Sparer TE, Reynolds TB. Cek1 regulates ß(1,3)-glucan exposure through calcineurin effectors in Candida albicans. PLoS Genet 2022; 18:e1010405. [PMID: 36121853 PMCID: PMC9521907 DOI: 10.1371/journal.pgen.1010405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 09/29/2022] [Accepted: 08/30/2022] [Indexed: 11/19/2022] Open
Abstract
In order to successfully induce disease, the fungal pathogen Candida albicans regulates exposure of antigens like the cell wall polysaccharide ß(1,3)-glucan to the host immune system. C. albicans covers (masks) ß(1,3)-glucan with a layer of mannosylated glycoproteins, which aids in immune system evasion by acting as a barrier to recognition by host pattern recognition receptors. Consequently, enhanced ß(1,3)-glucan exposure (unmasking) makes fungal cells more visible to host immune cells and facilitates more robust fungal clearance. However, an understanding of how C. albicans regulates its exposure levels of ß(1,3)-glucan is needed to leverage this phenotype. Signal transduction pathways and their corresponding effector genes mediating these changes are only beginning to be defined. Here, we report that the phosphatase calcineurin mediates unmasking of ß(1,3)-glucan in response to inputs from the Cek1 MAPK pathway and in response to caspofungin exposure. In contrast, calcineurin reduces ß-glucan exposure in response to high levels of extracellular calcium. Thus, depending on the input, calcineurin acts as a switchboard to regulate ß(1,3)-glucan exposure levels. By leveraging these differential ß(1,3)-glucan exposure phenotypes, we identified two novel effector genes in the calcineurin regulon, FGR41 and C1_11990W_A, that encode putative cell wall proteins and mediate masking/unmasking. Loss of either effector caused unmasking and attenuated virulence during systemic infection in mice. Furthermore, immunosuppression restored the colonization decrease seen in mice infected with the fgr41Δ/Δ mutant to wild-type levels, demonstrating a reliance on the host immune system for virulence attenuation. Thus, calcineurin and its downstream regulon are general regulators of unmasking.
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Affiliation(s)
- Andrew S. Wagner
- Department of Microbiology, University of Tennessee at Knoxville, Knoxville, Tennessee, United States of America
| | - Stephen W. Lumsdaine
- Department of Microbiology, University of Tennessee at Knoxville, Knoxville, Tennessee, United States of America
| | - Mikayla M. Mangrum
- Department of Microbiology, University of Tennessee at Knoxville, Knoxville, Tennessee, United States of America
| | - Ainsley E. King
- Department of Microbiology, University of Tennessee at Knoxville, Knoxville, Tennessee, United States of America
| | - Trevor J. Hancock
- Department of Microbiology, University of Tennessee at Knoxville, Knoxville, Tennessee, United States of America
| | - Timothy E. Sparer
- Department of Microbiology, University of Tennessee at Knoxville, Knoxville, Tennessee, United States of America
| | - Todd B. Reynolds
- Department of Microbiology, University of Tennessee at Knoxville, Knoxville, Tennessee, United States of America
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5
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DdaCrz1, a C2H2-Type Transcription Factor, Regulates Growth, Conidiation, and Stress Resistance in the Nematode-Trapping Fungus Drechslerella dactyloides. J Fungi (Basel) 2022; 8:jof8070750. [PMID: 35887505 PMCID: PMC9322116 DOI: 10.3390/jof8070750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Revised: 07/09/2022] [Accepted: 07/11/2022] [Indexed: 11/21/2022] Open
Abstract
The Ca2+/calmodulin-dependent signaling pathway regulates diverse cellular processes. Calcineurin is a calcium-dependent phosphatase acting in fungi mainly through Crz1, a zinc finger transcription factor. Although the likely involvement of Ca2+ in fungal carnivorism has been documented, how Crz1 functions in nematode-trapping fungi remains unknown. Here, we identified the Crz1 gene (named as DdaCrz1) in Drechslerella dactyloides, a species that forms constricting rings to trap nematodes. The deletion of DdaCrz1 significantly reduced hyphal growth and conidiation, trap formation, and ring cell inflation. Moreover, the mutation increased sensitivity to Mn2+ but decreased sensitivity to Ca2+, Mg2+, Zn2+, and Li+. Similarly, the mutant showed increased tolerance to osmotic stress but was more sensitive to Congo red, a cell wall-damaging agent. Our results confirmed the critical roles of the Ca2+/calmodulin-dependent signaling pathway in regulating growth, conidiation, and the stress response, and suggested its involvement in trapping nematodes.
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Liu C, Liu T, Lv Z, Qin M, Qu Z, Zhang Z, Li F, Chen D, Zhang X, Chen XL, Shen M. A Calcineurin Regulator MoRCN1 Is Important for Asexual Development, Stress Response, and Plant Infection of Magnaporthe oryzae. FRONTIERS IN PLANT SCIENCE 2022; 13:925645. [PMID: 35783935 PMCID: PMC9244802 DOI: 10.3389/fpls.2022.925645] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Accepted: 05/05/2022] [Indexed: 06/12/2023]
Abstract
The calcium/calcineurin signaling pathway plays a key role in the development and virulence of plant pathogenic fungi, but the regulation of this signaling pathway is still not clear. In this study, we identified a calcineurin regulator MoRCN1 in the plant pathogenic fungus Magnaporthe oryzae and found it is important for virulence by regulating the calcineurin pathway. MoRCN1 deletion mutants were severely decreased in colony growth and conidia formation. More importantly, the deletion of MoRCN1 led to a significant reduction in virulence due to defects in appressorium formation and invasive growth. The ΔMorcn1 mutants were more sensitive to different stresses and induced host ROS accumulation, suggesting a role of MoRCN1 in stress adaptation. We found that MoRCN1 directly interacted with the calcineurin catalytic subunit MoCNA and affected its protein stability, which was therefore important for regulating the calcineurin pathway. Transcriptome analysis showed that MoRCN1 significantly activated 491 genes and suppressed 337 genes in response to calcium ion, partially overlapped with the MoCRZ1-bound genes. Gene Ontology and KEGG pathway analyses indicated that MoRCN1-regulated genes were enriched in stress adaptation, lipid metabolism, and secondary metabolite biosynthesis, reflecting a function of MoRCN1 in host cell adaptation. Altogether, these results suggest MoRCN1 functions as a regulator of the calcium/calcineurin signaling pathway for fungal development and infection of host cells.
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Affiliation(s)
- Caiyun Liu
- Hubei Key Laboratory of Economic Forest Germplasm Improvement and Resources Comprehensive Utilization, College of Biology and Agricultural Resources, Huanggang Normal University, Huanggang, China
- State Key Laboratory of Agricultural Microbiology and Provincial Key Laboratory of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Tiangu Liu
- State Key Laboratory of Agricultural Microbiology and Provincial Key Laboratory of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Ziwei Lv
- State Key Laboratory of Agricultural Microbiology and Provincial Key Laboratory of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Mengyuan Qin
- State Key Laboratory of Agricultural Microbiology and Provincial Key Laboratory of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Zhiguang Qu
- State Key Laboratory of Agricultural Microbiology and Provincial Key Laboratory of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Ziwei Zhang
- State Key Laboratory of Agricultural Microbiology and Provincial Key Laboratory of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Fuyan Li
- State Key Laboratory of Agricultural Microbiology and Provincial Key Laboratory of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Deng Chen
- State Key Laboratory of Agricultural Microbiology and Provincial Key Laboratory of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Xinrong Zhang
- State Key Laboratory of Agricultural Microbiology and Provincial Key Laboratory of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Xiao-Lin Chen
- State Key Laboratory of Agricultural Microbiology and Provincial Key Laboratory of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Mi Shen
- Hubei Key Laboratory of Economic Forest Germplasm Improvement and Resources Comprehensive Utilization, College of Biology and Agricultural Resources, Huanggang Normal University, Huanggang, China
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7
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Iyer KR, Robbins N, Cowen LE. The role of Candida albicans stress response pathways in antifungal tolerance and resistance. iScience 2022; 25:103953. [PMID: 35281744 PMCID: PMC8905312 DOI: 10.1016/j.isci.2022.103953] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Human fungal pathogens are the causative agents of devastating diseases across the globe, and the increasing prevalence of drug resistance threatens to undermine the already limited treatment options. One prominent pathogen is the opportunistic fungus Candida albicans, which can cause both superficial and serious systemic infections in immunocompromised individuals. C. albicans antifungal drug resistance and antifungal tolerance are supported by diverse and expansive cellular stress response pathways. Some of the major players are the Ca2+-calmodulin-activated phosphatase calcineurin, the protein kinase C cell wall integrity pathway, and the molecular chaperone heat shock protein 90. Beyond these core signal transducers, several other enzymes and transcription factors have been implicated in both tolerance and resistance. Here, we highlight some of the major stress response pathways, key advances in identifying chemical matter to inhibit these pathways, and implications for C. albicans persistence in the host. Candida albicans can cause superficial and serious systemic infections in humans Stress response pathways regulate C. albicans antifungal resistance and tolerance Stress response regulators include calcineurin, Pkc1, Hsp90, and many others Stress response inhibitors could reduce the likelihood of fungi persisting in humans
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Affiliation(s)
- Kali R. Iyer
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, MaRS Centre, West Tower, Room 1638, Toronto, ON M5G 1M1, Canada
| | - Nicole Robbins
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, MaRS Centre, West Tower, Room 1638, Toronto, ON M5G 1M1, Canada
| | - Leah E. Cowen
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, MaRS Centre, West Tower, Room 1638, Toronto, ON M5G 1M1, Canada
- Corresponding author
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8
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Hsu IS, Strome B, Lash E, Robbins N, Cowen LE, Moses AM. A functionally divergent intrinsically disordered region underlying the conservation of stochastic signaling. PLoS Genet 2021; 17:e1009629. [PMID: 34506483 PMCID: PMC8457507 DOI: 10.1371/journal.pgen.1009629] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 09/22/2021] [Accepted: 08/06/2021] [Indexed: 12/18/2022] Open
Abstract
Stochastic signaling dynamics expand living cells' information processing capabilities. An increasing number of studies report that regulators encode information in their pulsatile dynamics. The evolutionary mechanisms that lead to complex signaling dynamics remain uncharacterized, perhaps because key interactions of signaling proteins are encoded in intrinsically disordered regions (IDRs), whose evolution is difficult to analyze. Here we focused on the IDR that controls the stochastic pulsing dynamics of Crz1, a transcription factor in fungi downstream of the widely conserved calcium signaling pathway. We find that Crz1 IDRs from anciently diverged fungi can all respond transiently to calcium stress; however, only Crz1 IDRs from the Saccharomyces clade support pulsatility, encode extra information, and rescue fitness in competition assays, while the Crz1 IDRs from distantly related fungi do none of the three. On the other hand, we find that Crz1 pulsing is conserved in the distantly related fungi, consistent with the evolutionary model of stabilizing selection on the signaling phenotype. Further, we show that a calcineurin docking site in a specific part of the IDRs appears to be sufficient for pulsing and show evidence for a beneficial increase in the relative calcineurin affinity of this docking site. We propose that evolutionary flexibility of functionally divergent IDRs underlies the conservation of stochastic signaling by stabilizing selection.
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Affiliation(s)
- Ian S. Hsu
- Department of Cell & Systems Biology, University of Toronto, Toronto, Canada
| | - Bob Strome
- Department of Cell & Systems Biology, University of Toronto, Toronto, Canada
| | - Emma Lash
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Nicole Robbins
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Leah E. Cowen
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Alan M. Moses
- Department of Cell & Systems Biology, University of Toronto, Toronto, Canada
- Department of Computer Science, University of Toronto, Toronto, Canada
- * E-mail:
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9
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Squizani ED, Reuwsaat JC, Motta H, Tavanti A, Kmetzsch L. Calcium: a central player in Cryptococcus biology. FUNGAL BIOL REV 2021. [DOI: 10.1016/j.fbr.2021.03.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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10
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Li W, Shrivastava M, Lu H, Jiang Y. Calcium-calcineurin signaling pathway in Candida albicans: A potential drug target. Microbiol Res 2021; 249:126786. [PMID: 33989979 DOI: 10.1016/j.micres.2021.126786] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Revised: 04/27/2021] [Accepted: 05/03/2021] [Indexed: 12/26/2022]
Abstract
Increased morbidity and mortality of candidiasis are a notable threat to the immunocompromised patients. At present, the types of drugs available to treat C. albicans infection are relatively limited. Moreover, the emergence of antifungal drug resistance of C. albicans makes the treatment of C. albicans infection more difficult. The calcium-calcineurin signaling pathway plays a crucial role in the survival and pathogenicity of C. albicans and may act as a potential target against C. albicans. In this review, we summarized functions of the calcium-calcineurin signaling pathway in several biological processes, compared the differences of this signaling pathway between C. albicans and humans, and described anti-C. albicans activity of inhibitors of this signaling pathway. We believe that targeting the calcium-calcineurin signaling pathway is a promising strategy to cope with C. albicans infection.
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Affiliation(s)
- Wanqian Li
- Department of Pharmacology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China
| | | | - Hui Lu
- Department of Pharmacology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China.
| | - Yuanying Jiang
- Department of Pharmacology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China.
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11
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Rai LS, Wijlick LV, Bougnoux ME, Bachellier-Bassi S, d'Enfert C. Regulators of commensal and pathogenic life-styles of an opportunistic fungus-Candida albicans. Yeast 2021; 38:243-250. [PMID: 33533498 DOI: 10.1002/yea.3550] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 01/28/2021] [Accepted: 01/29/2021] [Indexed: 12/12/2022] Open
Abstract
The yeast Candida albicans is primarily a commensal of humans that colonizes the mucosal surfaces of the gastrointestinal and genital tracts. Yet, C. albicans can under certain circumstances undergo a shift from commensalism to pathogenicity. This transition is governed by fungal factors such as morphological transitions, environmental cues for instance relationships with gut microbiota and the host immune system. C. albicans utilizes distinct sets of regulatory programs to colonize or infect its host and to evade the host defense systems. Moreover, an orchestrated iron acquisition mechanism operates to adapt to specific niches with variable iron availability. Studies on regulatory networks and morphogenesis of these two distinct modes of C. albicans growth, suggest that both yeast and hyphal forms exist in both growth patterns and the regulatory circuits are inter-connected. Here, we summarize current knowledge about C. albicans commensal-to-pathogen shift, its regulatory elements and their contribution to human disease.
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Affiliation(s)
- Laxmi Shanker Rai
- Unité Biologie et Pathogénicité Fongiques, Institut Pasteur, USC2019 INRA, Paris, France
| | - Lasse Van Wijlick
- Unité Biologie et Pathogénicité Fongiques, Institut Pasteur, USC2019 INRA, Paris, France
| | - Marie-Elisabeth Bougnoux
- Unité Biologie et Pathogénicité Fongiques, Institut Pasteur, USC2019 INRA, Paris, France.,Unité de Parasitologie-Mycologie, Service de Microbiologie Clinique, Hôpital Necker-Enfants-Malades, Assistance Publique des Hôpitaux de Paris (APHP), Paris, France
| | | | - Christophe d'Enfert
- Unité Biologie et Pathogénicité Fongiques, Institut Pasteur, USC2019 INRA, Paris, France
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12
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Qasim MN, Valle Arevalo A, Nobile CJ, Hernday AD. The Roles of Chromatin Accessibility in Regulating the Candida albicans White-Opaque Phenotypic Switch. J Fungi (Basel) 2021; 7:37. [PMID: 33435404 PMCID: PMC7826875 DOI: 10.3390/jof7010037] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 01/05/2021] [Accepted: 01/07/2021] [Indexed: 12/18/2022] Open
Abstract
Candida albicans, a diploid polymorphic fungus, has evolved a unique heritable epigenetic program that enables reversible phenotypic switching between two cell types, referred to as "white" and "opaque". These cell types are established and maintained by distinct transcriptional programs that lead to differences in metabolic preferences, mating competencies, cellular morphologies, responses to environmental signals, interactions with the host innate immune system, and expression of approximately 20% of genes in the genome. Transcription factors (defined as sequence specific DNA-binding proteins) that regulate the establishment and heritable maintenance of the white and opaque cell types have been a primary focus of investigation in the field; however, other factors that impact chromatin accessibility, such as histone modifying enzymes, chromatin remodelers, and histone chaperone complexes, also modulate the dynamics of the white-opaque switch and have been much less studied to date. Overall, the white-opaque switch represents an attractive and relatively "simple" model system for understanding the logic and regulatory mechanisms by which heritable cell fate decisions are determined in higher eukaryotes. Here we review recent discoveries on the roles of chromatin accessibility in regulating the C. albicans white-opaque phenotypic switch.
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Affiliation(s)
- Mohammad N. Qasim
- Department of Molecular and Cell Biology, University of California-Merced, Merced, CA 95343, USA; (M.N.Q.); (A.V.A.); (C.J.N.)
- Quantitative and Systems Biology Graduate Program, University of California-Merced, Merced, CA 95343, USA
| | - Ashley Valle Arevalo
- Department of Molecular and Cell Biology, University of California-Merced, Merced, CA 95343, USA; (M.N.Q.); (A.V.A.); (C.J.N.)
- Quantitative and Systems Biology Graduate Program, University of California-Merced, Merced, CA 95343, USA
| | - Clarissa J. Nobile
- Department of Molecular and Cell Biology, University of California-Merced, Merced, CA 95343, USA; (M.N.Q.); (A.V.A.); (C.J.N.)
- Health Sciences Research Institute, University of California-Merced, Merced, CA 95343, USA
| | - Aaron D. Hernday
- Department of Molecular and Cell Biology, University of California-Merced, Merced, CA 95343, USA; (M.N.Q.); (A.V.A.); (C.J.N.)
- Health Sciences Research Institute, University of California-Merced, Merced, CA 95343, USA
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13
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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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14
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Abstract
Calcium (Ca2+) is a universal signalling molecule of life. The Ca2+ signalling is an evolutionarily conserved process from prokaryotes to eukaryotes. Ca2+ at high concentration is deleterious to the cell; therefore, cell maintains a low resting level of intracellular free Ca2+ concentration ([Ca2+]c). The resting [Ca2+]c is tightly regulated, and a transient increase of the [Ca2+]c initiates a signalling cascade in the cell. Ca2+ signalling plays an essential role in various processes, including growth, development, reproduction, tolerance to stress conditions, and virulence in fungi. In this review, we describe the evolutionary aspects of Ca2+ signalling and cell functions of major Ca2+ signalling proteins in different fungi.
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Affiliation(s)
- Avishek Roy
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, India
| | - Ajeet Kumar
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, India
| | - Darshana Baruah
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, India
| | - Ranjan Tamuli
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, India
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15
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Martins-Santana L, Paula RGD, Silva AG, Lopes DCB, Silva RDN, Silva-Rocha R. CRZ1 regulator and calcium cooperatively modulate holocellulases gene expression in Trichoderma reesei QM6a. Genet Mol Biol 2020; 43:e20190244. [PMID: 32384133 PMCID: PMC7212764 DOI: 10.1590/1678-4685-gmb-2019-0244] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 12/22/2019] [Indexed: 02/06/2023] Open
Abstract
Trichoderma reesei is the main filamentous fungus used in industry to produce cellulases. Here we investigated the role of CRZ1 and Ca2+signaling in the fungus T. reesei QM6a concerning holocellulases production. For this, we first searched for potential CRZ1 binding sites in promoter regions of key genes coding holocellulases, as well as transcriptional regulators and sugar and calcium transporters. Using a nearly constructed T. reeseiAcrz1 strain, we demonstrated that most of the genes expected to be regulated by CRZ1 were affected in the mutant strain induced with sugarcane bagasse (SCB) and cellulose. In particular, our data demonstrate that Ca2+ acts synergistically with CRZ1 to modulate gene expression, but also exerts CRZ1-independent regulatory role in gene expression in T. reesei, highlighting the role of the major regulator Ca2+ on the signaling for holocellulases transcriptional control in the most part of cellulases genes here investigated. This work presents new evidence on the regulatory role of CRZ1 and Ca2+ sensing in the regulation of cellulolytic enzymes in T. reesei, evidencing significant and previously unknown function of this Ca2+sensing system in the control key transcriptional regulators (XYR1 and CRE1) and on the expression of genes related to sugar and Ca2+ transport.
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Affiliation(s)
- Leonardo Martins-Santana
- Universidade de São Paulo, Faculdade de Medicina de Ribeirão Preto, Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Laboratório de Biologia Sistêmica e Sintética, Ribeirão Preto, SP, Brazil.,Universidade de São Paulo, Faculdade de Medicina de Ribeirão Preto, Departamento de Bioquímica e Imunologia, Ribeirão Preto, SP, Brazil
| | - Renato Graciano de Paula
- Universidade de São Paulo, Faculdade de Medicina de Ribeirão Preto, Departamento de Bioquímica e Imunologia, Ribeirão Preto, SP, Brazil.,Universidade Federal do Espírito Santo, Centro de Ciências da Saúde, Departamento de Ciências Fisiológicas, Vitória, ES, Brazil
| | - Adriano Gomes Silva
- Universidade de São Paulo, Faculdade de Medicina de Ribeirão Preto, Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Laboratório de Biologia Sistêmica e Sintética, Ribeirão Preto, SP, Brazil
| | - Douglas Christian Borges Lopes
- Universidade de São Paulo, Faculdade de Medicina de Ribeirão Preto, Departamento de Bioquímica e Imunologia, Ribeirão Preto, SP, Brazil
| | - Roberto do Nascimento Silva
- Universidade de São Paulo, Faculdade de Medicina de Ribeirão Preto, Departamento de Bioquímica e Imunologia, Ribeirão Preto, SP, Brazil
| | - Rafael Silva-Rocha
- Universidade de São Paulo, Faculdade de Medicina de Ribeirão Preto, Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Laboratório de Biologia Sistêmica e Sintética, Ribeirão Preto, SP, 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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Childers DS, Avelar GM, Bain JM, Larcombe DE, Pradhan A, Budge S, Heaney H, Brown AJP. Impact of the Environment upon the Candida albicans Cell Wall and Resultant Effects upon Immune Surveillance. Curr Top Microbiol Immunol 2019; 425:297-330. [PMID: 31781866 DOI: 10.1007/82_2019_182] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The fungal cell wall is an essential organelle that maintains cellular morphology and protects the fungus from environmental insults. For fungal pathogens such as Candida albicans, it provides a degree of protection against attack by host immune defences. However, the cell wall also presents key epitopes that trigger host immunity and attractive targets for antifungal drugs. Rather than being a rigid shield, it has become clear that the fungal cell wall is an elastic organelle that permits rapid changes in cell volume and the transit of large liposomal particles such as extracellular vesicles. The fungal cell wall is also flexible in that it adapts to local environmental inputs, thereby enhancing the fitness of the fungus in these microenvironments. Recent evidence indicates that this cell wall adaptation affects host-fungus interactions by altering the exposure of major cell wall epitopes that are recognised by innate immune cells. Therefore, we discuss the impact of environmental adaptation upon fungal cell wall structure, and how this affects immune recognition, focussing on C. albicans and drawing parallels with other fungal pathogens.
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Affiliation(s)
- Delma S Childers
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK
| | - Gabriela M Avelar
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK
| | - Judith M Bain
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK
| | - Daniel E Larcombe
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK
- Medical Research Council Centre for Medical Mycology, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter, EX4 4QD, UK
| | - Arnab Pradhan
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK
- Medical Research Council Centre for Medical Mycology, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter, EX4 4QD, UK
| | - Susan Budge
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK
| | - Helen Heaney
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK
| | - Alistair J P Brown
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK.
- Medical Research Council Centre for Medical Mycology, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter, EX4 4QD, UK.
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18
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The transcription factor FgCrz1A is essential for fungal development, virulence, deoxynivalenol biosynthesis and stress responses in Fusarium graminearum. Curr Genet 2018; 65:153-166. [DOI: 10.1007/s00294-018-0853-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2018] [Revised: 06/02/2018] [Accepted: 06/04/2018] [Indexed: 10/14/2022]
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19
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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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20
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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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21
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Xie JL, Qin L, Miao Z, Grys BT, Diaz JDLC, Ting K, Krieger JR, Tong J, Tan K, Leach MD, Ketela T, Moran MF, Krysan DJ, Boone C, Andrews BJ, Selmecki A, Ho Wong K, Robbins N, Cowen LE. The Candida albicans transcription factor Cas5 couples stress responses, drug resistance and cell cycle regulation. Nat Commun 2017; 8:499. [PMID: 28894103 PMCID: PMC5593949 DOI: 10.1038/s41467-017-00547-y] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 07/06/2017] [Indexed: 12/16/2022] Open
Abstract
The capacity to coordinate environmental sensing with initiation of cellular responses underpins microbial survival and is crucial for virulence and stress responses in microbial pathogens. Here we define circuitry that enables the fungal pathogen Candida albicans to couple cell cycle dynamics with responses to cell wall stress induced by echinocandins, a front-line class of antifungal drugs. We discover that the C. albicans transcription factor Cas5 is crucial for proper cell cycle dynamics and responses to echinocandins, which inhibit β-1,3-glucan synthesis. Cas5 has distinct transcriptional targets under basal and stress conditions, is activated by the phosphatase Glc7, and can regulate the expression of target genes in concert with the transcriptional regulators Swi4 and Swi6. Thus, we illuminate a mechanism of transcriptional control that couples cell wall integrity with cell cycle regulation, and uncover circuitry governing antifungal drug resistance.Cas5 is a transcriptional regulator of responses to cell wall stress in the fungal pathogen Candida albicans. Here, Xie et al. show that Cas5 also modulates cell cycle dynamics and responses to antifungal drugs.
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Affiliation(s)
- Jinglin L Xie
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada, M5G 1M1
| | - Longguang Qin
- Faculty of Health Sciences, University of Macau, Macau SAR, 999078, China
| | - Zhengqiang Miao
- Faculty of Health Sciences, University of Macau, Macau SAR, 999078, China
| | - Ben T Grys
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada, M5G 1M1
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, Canada, M5S 3E1
| | - Jacinto De La Cruz Diaz
- Department of Microbiology and Immunology, University of Rochester, Rochester, NY, 14642, USA
| | - Kenneth Ting
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada, M5G 1M1
| | - Jonathan R Krieger
- The Hospital for Sick Children, SPARC Biocentre, Toronto, ON, Canada, M5G 0A4
| | - Jiefei Tong
- The Hospital for Sick Children, Program in Cell Biology, Peter Gilgan Centre for Research and Learning, Toronto, ON, Canada, M5G 0A4
| | - Kaeling Tan
- Faculty of Health Sciences, University of Macau, Macau SAR, 999078, China
| | - Michelle D Leach
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada, M5G 1M1
- Aberdeen Fungal Group, School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Abderdeen, AB252ZD, UK
| | - Troy Ketela
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada, M5G 1M1
| | - Michael F Moran
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada, M5G 1M1
- The Hospital for Sick Children, SPARC Biocentre, Toronto, ON, Canada, M5G 0A4
- The Hospital for Sick Children, Program in Cell Biology, Peter Gilgan Centre for Research and Learning, Toronto, ON, Canada, M5G 0A4
| | - Damian J Krysan
- Department of Microbiology and Immunology, University of Rochester, Rochester, NY, 14642, USA
- Department of Pediatrics and Microbiology/Immunology, University of Rochester, Rochester, NY, 14642, USA
| | - Charles Boone
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada, M5G 1M1
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, Canada, M5S 3E1
| | - Brenda J Andrews
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada, M5G 1M1
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, Canada, M5S 3E1
| | - Anna Selmecki
- Department of Medical Microbiology and Immunology, Creighton University School of Medicine, Omaha, NE, 68178, USA
| | - Koon Ho Wong
- Faculty of Health Sciences, University of Macau, Macau SAR, 999078, China
| | - Nicole Robbins
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada, M5G 1M1
| | - Leah E Cowen
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada, M5G 1M1.
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22
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Ballou ER, Avelar GM, Childers DS, Mackie J, Bain JM, Wagener J, Kastora SL, Panea MD, Hardison SE, Walker LA, Erwig LP, Munro CA, Gow NAR, Brown GD, MacCallum DM, Brown AJP. Lactate signalling regulates fungal β-glucan masking and immune evasion. Nat Microbiol 2016; 2:16238. [PMID: 27941860 DOI: 10.1038/nmicrobiol.2016.238] [Citation(s) in RCA: 173] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 10/21/2016] [Indexed: 02/06/2023]
Abstract
As they proliferate, fungi expose antigens at their cell surface that are potent stimulators of the innate immune response, and yet the commensal fungus Candida albicans is able to colonize immuno competent individuals. We show that C. albicans may evade immune detection by presenting a moving immunological target. We report that the exposure of β-glucan, a key pathogen-associated molecular pattern (PAMP) located at the cell surface of C. albicans and other pathogenic Candida species, is modulated in response to changes in the carbon source. Exposure to lactate induces β-glucan masking in C. albicans via a signalling pathway that has recruited an evolutionarily conserved receptor (Gpr1) and transcriptional factor (Crz1) from other well-characterized pathways. In response to lactate, these regulators control the expression of cell-wall-related genes that contribute to β-glucan masking. This represents the first description of active PAMP masking by a Candida species, a process that reduces the visibility of the fungus to the immune system.
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Affiliation(s)
- Elizabeth R Ballou
- Aberdeen Fungal Group, MRC Centre for Medical Mycology, School of Medicine, Medical Sciences and Nutrition, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Gabriela M Avelar
- Aberdeen Fungal Group, MRC Centre for Medical Mycology, School of Medicine, Medical Sciences and Nutrition, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Delma S Childers
- Aberdeen Fungal Group, MRC Centre for Medical Mycology, School of Medicine, Medical Sciences and Nutrition, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Joanna Mackie
- Aberdeen Fungal Group, MRC Centre for Medical Mycology, School of Medicine, Medical Sciences and Nutrition, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Judith M Bain
- Aberdeen Fungal Group, MRC Centre for Medical Mycology, School of Medicine, Medical Sciences and Nutrition, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Jeanette Wagener
- Aberdeen Fungal Group, MRC Centre for Medical Mycology, School of Medicine, Medical Sciences and Nutrition, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Stavroula L Kastora
- Aberdeen Fungal Group, MRC Centre for Medical Mycology, School of Medicine, Medical Sciences and Nutrition, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Mirela D Panea
- Aberdeen Fungal Group, MRC Centre for Medical Mycology, School of Medicine, Medical Sciences and Nutrition, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Sarah E Hardison
- Aberdeen Fungal Group, MRC Centre for Medical Mycology, School of Medicine, Medical Sciences and Nutrition, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Louise A Walker
- Aberdeen Fungal Group, MRC Centre for Medical Mycology, School of Medicine, Medical Sciences and Nutrition, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Lars P Erwig
- Aberdeen Fungal Group, MRC Centre for Medical Mycology, School of Medicine, Medical Sciences and Nutrition, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Carol A Munro
- Aberdeen Fungal Group, MRC Centre for Medical Mycology, School of Medicine, Medical Sciences and Nutrition, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Neil A R Gow
- Aberdeen Fungal Group, MRC Centre for Medical Mycology, School of Medicine, Medical Sciences and Nutrition, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Gordon D Brown
- Aberdeen Fungal Group, MRC Centre for Medical Mycology, School of Medicine, Medical Sciences and Nutrition, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Donna M MacCallum
- Aberdeen Fungal Group, MRC Centre for Medical Mycology, School of Medicine, Medical Sciences and Nutrition, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Alistair J P Brown
- Aberdeen Fungal Group, MRC Centre for Medical Mycology, School of Medicine, Medical Sciences and Nutrition, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
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23
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Majeská Čudejková M, Vojta P, Valík J, Galuszka P. Quantitative and qualitative transcriptome analysis of four industrial strains of Claviceps purpurea with respect to ergot alkaloid production. N Biotechnol 2016; 33:743-754. [PMID: 26827914 DOI: 10.1016/j.nbt.2016.01.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Revised: 12/22/2015] [Accepted: 01/05/2016] [Indexed: 01/14/2023]
Abstract
The fungus Claviceps purpurea is a biotrophic phytopathogen widely used in the pharmaceutical industry for its ability to produce ergot alkaloids (EAs). The fungus attacks unfertilized ovaries of grasses and forms sclerotia, which represent the only type of tissue where the synthesis of EAs occurs. The biosynthetic pathway of EAs has been extensively studied; however, little is known concerning its regulation. Here, we present the quantitative transcriptome analysis of the sclerotial and mycelial tissues providing a comprehensive view of transcriptional differences between the tissues that produce EAs and those that do not produce EAs and the pathogenic and non-pathogenic lifestyle. The results indicate metabolic changes coupled with sclerotial differentiation, which are likely needed as initiation factors for EA biosynthesis. One of the promising factors seems to be oxidative stress. Here, we focus on the identification of putative transcription factors and regulators involved in sclerotial differentiation, which might be involved in EA biosynthesis. To shed more light on the regulation of EA composition, whole transcriptome analysis of four industrial strains differing in their alkaloid spectra was performed. The results support the hypothesis proposing the composition of the amino acid pool in sclerotia to be an important factor regulating the final structure of the ergopeptines produced by Claviceps purpurea.
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Affiliation(s)
- Mária Majeská Čudejková
- Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University in Olomouc, Šlechtitelů 27, 783 71 Olomouc, Czech Republic.
| | - Petr Vojta
- Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University in Olomouc, Šlechtitelů 27, 783 71 Olomouc, Czech Republic; Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacký University Olomouc, Hněvotínská 1333/5, 779 00 Olomouc, Czech Republic
| | - Josef Valík
- Teva Czech Industries s.r.o., Ostravská 305/29, 747 70 Opava-Komárov, Czech Republic
| | - Petr Galuszka
- Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University in Olomouc, Šlechtitelů 27, 783 71 Olomouc, Czech Republic
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24
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The transcription factor VpCRZ1 is required for fruiting body formation and pathogenicity in Valsa pyri. Microb Pathog 2016; 95:101-110. [PMID: 26970115 DOI: 10.1016/j.micpath.2016.02.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2015] [Revised: 02/24/2016] [Accepted: 02/26/2016] [Indexed: 11/20/2022]
Abstract
Valsa pyri is a fatal pathogenic fungus that causes pear and apple canker disease. To date, its cellular development and pathogenicity have been poorly understood. In this study, a V. pyri Ca(2+)/calcineurin-dependent transcription factor CRZ1 (VpCRZ1) is identified and functionally characterized. The △VpCRZ1 mutant exhibits impaired pathogenicity and is no longer able to form fruiting body. Interestingly, this mutant also exhibits enhanced pigment deposition and increased resistance to cell wall perturbing agents including SDS, Congo red and calcofluor white (CFW). The expression levels of Congo red resistance genes (VpRCR1 and VpRCR2) and chitin synthetase genes (VpCHS2 and VpCHS6) are upregulated in the △VpCRZ1 mutant compared to the wild type. Furthermore, We show that a VpCRZ1: eGFP fusion protein localizes to the nucleus in a Ca(2+)-dependent manner similar to its homologs in other fungi, and that the VpFKS1, VpPMC1, VpPMC2, VpPMR1, and VpPMA1 genes are regulated by VpCRZ1 in response to Ca(2+) levels. Together, these results suggest that VpCRZ1 is a Ca(2+)-dependent transcription factor and required for regulating mycelial morphology, fruiting body formation, and virulence of this important pear and apple pathogen.
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25
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Albataineh MT, Kadosh D. Regulatory roles of phosphorylation in model and pathogenic fungi. Med Mycol 2015; 54:333-52. [PMID: 26705834 PMCID: PMC4818690 DOI: 10.1093/mmy/myv098] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 11/01/2015] [Indexed: 12/25/2022] Open
Abstract
Over the past 20 years, considerable advances have been made toward our understanding
of how post-translational modifications affect a wide variety of biological
processes, including morphology and virulence, in medically important fungi.
Phosphorylation stands out as a key molecular switch and regulatory modification that
plays a critical role in controlling these processes. In this article, we first
provide a comprehensive and up-to-date overview of the regulatory roles that both
Ser/Thr and non-Ser/Thr kinases and phosphatases play in model and pathogenic fungi.
Next, we discuss the impact of current global approaches that are being used to
define the complete set of phosphorylation targets (phosphoproteome) in medically
important fungi. Finally, we provide new insights and perspectives into the potential
use of key regulatory kinases and phosphatases as targets for the development of
novel and more effective antifungal strategies.
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Affiliation(s)
- Mohammad T Albataineh
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229
| | - David Kadosh
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229
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Li F, Wang ZL, Zhang LB, Ying SH, Feng MG. The role of three calcineurin subunits and a related transcription factor (Crz1) in conidiation, multistress tolerance and virulence in Beauveria bassiana. Appl Microbiol Biotechnol 2014; 99:827-40. [DOI: 10.1007/s00253-014-6124-6] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2014] [Revised: 09/28/2014] [Accepted: 09/30/2014] [Indexed: 11/25/2022]
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Juvvadi PR, Lamoth F, Steinbach WJ. Calcineurin as a Multifunctional Regulator: Unraveling Novel Functions in Fungal Stress Responses, Hyphal Growth, Drug Resistance, and Pathogenesis. FUNGAL BIOL REV 2014; 28:56-69. [PMID: 25383089 DOI: 10.1016/j.fbr.2014.02.004] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Calcineurin signaling plays diverse roles in fungi in regulating stress responses, morphogenesis and pathogenesis. Although calcineurin signaling is conserved among fungi, recent studies indicate important divergences in calcineurin-dependent cellular functions among different human fungal pathogens. Fungal pathogens utilize the calcineurin pathway to effectively survive the host environment and cause life-threatening infections. The immunosuppressive calcineurin inhibitors (FK506 and cyclosporine A) are active against fungi, making targeting calcineurin a promising antifungal drug development strategy. Here we summarize current knowledge on calcineurin in yeasts and filamentous fungi, and review the importance of understanding fungal-specific attributes of calcineurin to decipher fungal pathogenesis and develop novel antifungal therapeutic approaches.
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Affiliation(s)
- Praveen R Juvvadi
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Duke University Medical Center, Durham NC, USA
| | - Frédéric Lamoth
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Duke University Medical Center, Durham NC, USA ; Infectious Diseases Service, Department of Medicine, Lausanne University Hospital, Lausanne, Switzerland ; Institute of Microbiology, Lausanne University Hospital, Lausanne, Switzerland
| | - William J Steinbach
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Duke University Medical Center, Durham NC, USA ; Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham NC, USA
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Childers DS, Mundodi V, Banerjee M, Kadosh D. A 5' UTR-mediated translational efficiency mechanism inhibits the Candida albicans morphological transition. Mol Microbiol 2014; 92:570-85. [PMID: 24601998 DOI: 10.1111/mmi.12576] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/05/2014] [Indexed: 01/09/2023]
Abstract
While virulence properties of Candida albicans, the most commonly isolated human fungal pathogen, are controlled by transcriptional and post-translational mechanisms, considerably little is known about the role of post-transcriptional, and particularly translational, mechanisms. We demonstrate that UME6, a key filament-specific transcriptional regulator whose expression level is sufficient to determine C. albicans morphology and promote virulence, has one of the longest 5' untranslated regions (UTRs) identified in fungi to date, which is predicted to form a complex and extremely stable secondary structure. The 5' UTR inhibits the ability of UME6, when expressed at constitutive high levels, to drive complete hyphal growth, but does not cause a reduction in UME6 transcript. Deletion of the 5' UTR increases C. albicans filamentation under a variety of conditions but does not affect UME6 transcript level or induction kinetics. We show that the 5' UTR functions to inhibit Ume6 protein expression under several filament-inducing conditions and specifically reduces association of the UME6 transcript with polysomes. Overall, our findings suggest that translational efficiency mechanisms, known to regulate diverse biological processes in bacterial and viral pathogens as well as higher eukaryotes, have evolved to inhibit and fine-tune morphogenesis, a key virulence trait of many human fungal pathogens.
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Affiliation(s)
- Delma S Childers
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Dr., MC: 7758, San Antonio, TX, 78229-3900, USA
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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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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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Zhang T, Xu Q, Sun X, Li H. The calcineurin-responsive transcription factor Crz1 is required for conidation, full virulence and DMI resistance in Penicillium digitatum. Microbiol Res 2013; 168:211-22. [DOI: 10.1016/j.micres.2012.11.006] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2012] [Revised: 11/07/2012] [Accepted: 11/11/2012] [Indexed: 10/27/2022]
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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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Lev S, Desmarini D, Chayakulkeeree M, Sorrell TC, Djordjevic JT. The Crz1/Sp1 transcription factor of Cryptococcus neoformans is activated by calcineurin and regulates cell wall integrity. PLoS One 2012; 7:e51403. [PMID: 23251520 PMCID: PMC3520850 DOI: 10.1371/journal.pone.0051403] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2012] [Accepted: 11/01/2012] [Indexed: 11/22/2022] Open
Abstract
Cryptococcus neoformans survives host temperature and regulates cell wall integrity via a calcium-dependent phosphatase, calcineurin. However, downstream effectors of C. neoformans calcineurin are largely unknown. In S. cerevisiae and other fungal species, a calcineurin-dependent transcription factor Crz1, translocates to nuclei upon activation and triggers expression of target genes. We now show that the C. neoformans Crz1 ortholog (Crz1/Sp1), previously identified as a protein kinase C target during starvation, is a bona fide target of calcineurin under non-starvation conditions, during cell wall stress and growth at high temperature. Both the calcineurin-defective mutant, Δcna1, and a CRZ1/SP1 mutant (Δcrz1) were susceptible to cell wall perturbing agents. Furthermore, expression of the chitin synthase encoding gene, CHS6, was reduced in both mutants. We tracked the subcellular localization of Crz1-GFP in WT C. neoformans and Δcna1 in response to different stimuli, in the presence and absence of the calcineurin inhibitor, FK506. Exposure to elevated temperature (30–37°C vs 25°C) and extracellular calcium caused calcineurin-dependent nuclear accumulation of Crz1-GFP. Unexpectedly, 1M salt and heat shock triggered calcineurin-independent Crz1-GFP sequestration within cytosolic and nuclear puncta. To our knowledge, punctate cytosolic distribution, as opposed to nuclear targeting, is a unique feature of C. neoformans Crz1. We conclude that Crz1 is selectively activated by calcium/calcineurin-dependent and independent signals depending on the environmental conditions.
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Affiliation(s)
- Sophie Lev
- Centre for Infectious Diseases and Microbiology, Sydney Medical School and Westmead Millennium Institute, University of Sydney, Westmead, New South Wales, Australia
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The calcineurin dependent transcription factor TacA is involved in development and the stress response of Dictyostelium discoideum. Eur J Cell Biol 2012; 91:789-99. [DOI: 10.1016/j.ejcb.2012.07.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2012] [Revised: 07/20/2012] [Accepted: 07/24/2012] [Indexed: 11/20/2022] Open
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Dai B, Wang Y, Li D, Xu Y, Liang R, Zhao L, Cao Y, Jia J, Jiang Y. Hsp90 is involved in apoptosis of Candida albicans by regulating the calcineurin-caspase apoptotic pathway. PLoS One 2012; 7:e45109. [PMID: 23028789 PMCID: PMC3445616 DOI: 10.1371/journal.pone.0045109] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Accepted: 08/14/2012] [Indexed: 11/27/2022] Open
Abstract
Candida albicans is the most common human fungal pathogen. Recent evidence has revealed the occurrence of apoptosis in C. albicans that is inducible by environmental stresses such as hydrogen peroxide, acetic acid, and amphotericin B. Apoptosis is regulated by the calcineurin-caspase pathway in C. albicans, and calcineurin is under the control of Hsp90 in echinocandin resistance. However, the role of Hsp90 in apoptosis of C. albicans remains unclear. In this study, we investigated the role of Hsp90 in apoptosis of C. albicans by using an Hsp90-compromised strain tetO-HSP90/hsp90 and found that upon apoptotic stimuli, including hydrogen peroxide, acetic acid or amphotericin B treatment, less apoptosis occurred, less ROS was produced, and more cells survived in the Hsp90-compromised strain compared with the Hsp90/Hsp90 wild-type strain. In addition, Hsp90-compromised cells were defective in up-regulating caspase-encoding gene CaMCA1 expression and activating caspase activity upon the apoptotic stimuli. Investigations on the relationship between Hsp90 and calcineurin revealed that activation of calcineurin could up-regulate apoptosis but could not further down-regulate apoptosis in Hsp90-compromised cells, indicating that calcineurin was downstream of Hsp90. Hsp90 inhibitor geldanamycin (GdA) could further decrease the apoptosis in calcineurin-pathway-defect strains, indicating that compromising Hsp90 function had a stronger effect than compromising calcineurin function on apoptosis. Collectively, this study demonstrated that compromised Hsp90 reduced apoptosis in C. albicans, partially through downregulating the calcineurin-caspase pathway.
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Affiliation(s)
- BaoDi Dai
- School of Pharmacy, Second Military Medical University, Shanghai, China
| | - Yan Wang
- School of Pharmacy, Second Military Medical University, Shanghai, China
| | - DeDong Li
- School of Pharmacy, Second Military Medical University, Shanghai, China
| | - Yi Xu
- Department of Pharmacy, General Hospital of Jinan Military Command Region, Jinan, China
| | - RongMei Liang
- Department of Clinical Pharmacy, General Hospital of Chengdu Military Command Region, Chengdu, China
| | - LanXue Zhao
- School of Pharmacy, Second Military Medical University, Shanghai, China
| | - YongBing Cao
- School of Pharmacy, Second Military Medical University, Shanghai, China
| | - JianHui Jia
- Department of Pharmacology, School of Life Science and Biopharmacology, Shenyang Pharmaceutical University, Shenyang, China
| | - YuanYing Jiang
- School of Pharmacy, Second Military Medical University, Shanghai, China
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Zhang J, Silao FGS, Bigol UG, Bungay AAC, Nicolas MG, Heitman J, Chen YL. Calcineurin is required for pseudohyphal growth, virulence, and drug resistance in Candida lusitaniae. PLoS One 2012; 7:e44192. [PMID: 22952924 PMCID: PMC3432075 DOI: 10.1371/journal.pone.0044192] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Accepted: 07/30/2012] [Indexed: 11/19/2022] Open
Abstract
Candida lusitaniae is an emerging fungal pathogen that infects immunocompromised patients including HIV/AIDS, cancer, and neonatal pediatric patients. Though less prevalent than other Candida species, C. lusitaniae is unique in its ability to develop resistance to amphotericin B. We investigated the role of the calcium-activated protein phosphatase calcineurin in several virulence attributes of C. lusitaniae including pseudohyphal growth, serum survival, and growth at 37°C. We found that calcineurin and Crz1, a C. albicans Crz1 homolog acting as a downstream target of calcineurin, are required for C. lusitaniae pseudohyphal growth, a process for which the underlying mechanism remains largely unknown in C. lusitaniae but hyphal growth is fundamental to C. albicans virulence. We demonstrate that calcineurin is required for cell wall integrity, ER stress response, optimal growth in serum, virulence in a murine systemic infection model, and antifungal drug tolerance in C. lusitaniae. To further examine the potential of targeting the calcineurin signaling cascade for antifungal drug development, we examined the activity of a calcineurin inhibitor FK506 in combination with caspofungin against echinocandin resistant C. lusitaniae clinical isolates. Broth microdilution and drug disk diffusion assays demonstrate that FK506 has synergistic fungicidal activity with caspofungin against echinocandin resistant isolates. Our findings reveal that pseudohyphal growth is controlled by the calcineurin signaling cascade, and highlight the potential use of calcineurin inhibitors and caspofungin for emerging drug-resistant C. lusitaniae infections.
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Affiliation(s)
- Jing Zhang
- Department of Molecular Genetics and Microbiology, Duke University, Durham, North Carolina, United States of America
- Department of Chemistry, Duke University, Durham, North Carolina, United States of America
| | - Fitz Gerald S. Silao
- Department of Microbiology and Parasitology, University of Perpetual Help – Dr. Jose G. Tamayo Medical University, Biñan, Laguna, Philippines
| | - Ursela G. Bigol
- Environment and Biotechnology Division, Department of Science and Technology, Bicutan, Philippines
| | - Alice Alma C. Bungay
- Department of Microbiology and Parasitology, University of Perpetual Help – Dr. Jose G. Tamayo Medical University, Biñan, Laguna, Philippines
- National Institutes of Health-Philippines, University of the Philippines, Manila, Philippines
| | - Marilou G. Nicolas
- National Institutes of Health-Philippines, University of the Philippines, Manila, Philippines
| | - Joseph Heitman
- Department of Molecular Genetics and Microbiology, Duke University, Durham, North Carolina, United States of America
- * E-mail: (JH); (Y-LC)
| | - Ying-Lien Chen
- Department of Molecular Genetics and Microbiology, Duke University, Durham, North Carolina, United States of America
- * E-mail: (JH); (Y-LC)
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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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Shapiro RS, Robbins N, Cowen LE. Regulatory circuitry governing fungal development, drug resistance, and disease. Microbiol Mol Biol Rev 2011; 75:213-67. [PMID: 21646428 PMCID: PMC3122626 DOI: 10.1128/mmbr.00045-10] [Citation(s) in RCA: 384] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Pathogenic fungi have become a leading cause of human mortality due to the increasing frequency of fungal infections in immunocompromised populations and the limited armamentarium of clinically useful antifungal drugs. Candida albicans, Cryptococcus neoformans, and Aspergillus fumigatus are the leading causes of opportunistic fungal infections. In these diverse pathogenic fungi, complex signal transduction cascades are critical for sensing environmental changes and mediating appropriate cellular responses. For C. albicans, several environmental cues regulate a morphogenetic switch from yeast to filamentous growth, a reversible transition important for virulence. Many of the signaling cascades regulating morphogenesis are also required for cells to adapt and survive the cellular stresses imposed by antifungal drugs. Many of these signaling networks are conserved in C. neoformans and A. fumigatus, which undergo distinct morphogenetic programs during specific phases of their life cycles. Furthermore, the key mechanisms of fungal drug resistance, including alterations of the drug target, overexpression of drug efflux transporters, and alteration of cellular stress responses, are conserved between these species. This review focuses on the circuitry regulating fungal morphogenesis and drug resistance and the impact of these pathways on virulence. Although the three human-pathogenic fungi highlighted in this review are those most frequently encountered in the clinic, they represent a minute fraction of fungal diversity. Exploration of the conservation and divergence of core signal transduction pathways across C. albicans, C. neoformans, and A. fumigatus provides a foundation for the study of a broader diversity of pathogenic fungi and a platform for the development of new therapeutic strategies for fungal disease.
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Affiliation(s)
| | | | - Leah E. Cowen
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
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Chen YL, Brand A, Morrison EL, Silao FGS, Bigol UG, Malbas FF, Nett JE, Andes DR, Solis NV, Filler SG, Averette A, Heitman J. Calcineurin controls drug tolerance, hyphal growth, and virulence in Candida dubliniensis. EUKARYOTIC CELL 2011; 10:803-19. [PMID: 21531874 PMCID: PMC3127677 DOI: 10.1128/ec.00310-10] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2010] [Accepted: 04/11/2011] [Indexed: 01/09/2023]
Abstract
Candida dubliniensis is an emerging pathogenic yeast species closely related to Candida albicans and frequently found colonizing or infecting the oral cavities of HIV/AIDS patients. Drug resistance during C. dubliniensis infection is common and constitutes a significant therapeutic challenge. The calcineurin inhibitor FK506 exhibits synergistic fungicidal activity with azoles or echinocandins in the fungal pathogens C. albicans, Cryptococcus neoformans, and Aspergillus fumigatus. In this study, we show that calcineurin is required for cell wall integrity and wild-type tolerance of C. dubliniensis to azoles and echinocandins; hence, these drugs are candidates for combination therapy with calcineurin inhibitors. In contrast to C. albicans, in which the roles of calcineurin and Crz1 in hyphal growth are unclear, here we show that calcineurin and Crz1 play a clearly demonstrable role in hyphal growth in response to nutrient limitation in C. dubliniensis. We further demonstrate that thigmotropism is controlled by Crz1, but not calcineurin, in C. dubliniensis. Similar to C. albicans, C. dubliniensis calcineurin enhances survival in serum. C. dubliniensis calcineurin and crz1/crz1 mutants exhibit attenuated virulence in a murine systemic infection model, likely attributable to defects in cell wall integrity, hyphal growth, and serum survival. Furthermore, we show that C. dubliniensis calcineurin mutants are unable to establish murine ocular infection or form biofilms in a rat denture model. That calcineurin is required for drug tolerance and virulence makes fungus-specific calcineurin inhibitors attractive candidates for combination therapy with azoles or echinocandins against emerging C. dubliniensis infections.
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Affiliation(s)
- Ying-Lien Chen
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina
| | - Alexandra Brand
- Aberdeen Fungal Group, School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Emma L. Morrison
- Aberdeen Fungal Group, School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Fitz Gerald S. Silao
- Department of Microbiology and Parasitology, University of Perpetual Help-Dr. Jose G. Tamayo Medical University, Biñan, Laguna, Philippines
| | - Ursela G. Bigol
- Environment and Biotechnology Division, Department of Science and Technology, Bicutan, Philippines
| | | | - Jeniel E. Nett
- Departments of Medicine
- Medical Microbiology and Immunology, University of Wisconsin
- William S. Middleton Memorial Veterans Hospital, Madison, Wisconsin
| | - David R. Andes
- Departments of Medicine
- Medical Microbiology and Immunology, University of Wisconsin
- William S. Middleton Memorial Veterans Hospital, Madison, Wisconsin
| | - Norma V. Solis
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, California
| | - Scott G. Filler
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, California
- David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Anna Averette
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina
| | - Joseph Heitman
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina
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Sipling T, Zhai C, Panaretou B. Emw1p/YNL313cp is essential for maintenance of the cell wall in Saccharomyces cerevisiae. MICROBIOLOGY-SGM 2011; 157:1032-1041. [PMID: 21273246 DOI: 10.1099/mic.0.045971-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
There are six essential genes in the Saccharomyces cerevisiae genome which encode proteins bearing the tetratricopeptide repeat (TPR) domain that mediates protein-protein interaction. Thus far, the function of one of them, YNL313c, remains unknown. Our conditional mutants of YNL313c display osmoremedial temperature sensitivity, hypersensitivity to both Calcofluor White and low concentrations of SDS, and osmoremedial caffeine sensitivity. These are hallmarks of mutants that display cell wall defects. Accordingly we rename the gene as EMW1 (essential for maintenance of the cell wall). Loss of Emw1p function is not associated with abrogation of the cell wall integrity (CWI) MAP kinase cascade. Instead, emw1(ts) mutants activate this cascade even at permissive temperature, indicating that loss of Emw1p function does not cause a defect in sensors and effectors of cell wall signalling, but leads to a cell wall defect directly. Constitutive activation of the CWI cascade is reflected by the overproduction of chitin by emw1(ts) mutants, a compensatory response frequently displayed by cell wall mutants. Growth is restored to emw1(ts) mutants incubated at otherwise non-permissive temperature when GFA1 is overexpressed. GFA1 encodes the hexosephosphate aminotransferase that catalyses the rate-limiting step in the pathway that synthesizes the chitin precursor UDP-GlcNAc. The possibility that Emw1p is required for function of Gfa1p was ruled out, because the emw1(ts) phenotype persists when the requirement for Gfa1p is bypassed. Furthermore, if loss of Emw1p function leads to loss of function of Gfa1p, then chitin synthesis would be diminished. Instead, a stimulation of the synthesis of this polymer is detected. Consequently, the defect associated with emw1(ts) mutants may be associated with compromise in one of the remaining processes that depend on UDP-GlcNAc, namely N-glycosylation or glycosylphosphatidylinositol (GPI)-anchor synthesis.
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Affiliation(s)
- Tatjana Sipling
- Pharmaceutical Science Division, King's College London, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NH, UK
| | - Chao Zhai
- Pharmaceutical Science Division, King's College London, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NH, UK
| | - Barry Panaretou
- Pharmaceutical Science Division, King's College London, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NH, UK
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Miyazaki T, Yamauchi S, Inamine T, Nagayoshi Y, Saijo T, Izumikawa K, Seki M, Kakeya H, Yamamoto Y, Yanagihara K, Miyazaki Y, Kohno S. Roles of calcineurin and Crz1 in antifungal susceptibility and virulence of Candida glabrata. Antimicrob Agents Chemother 2010; 54:1639-43. [PMID: 20100876 PMCID: PMC2849377 DOI: 10.1128/aac.01364-09] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2009] [Revised: 11/15/2009] [Accepted: 01/15/2010] [Indexed: 11/20/2022] Open
Abstract
A Candida glabrata calcineurin mutant exhibited increased susceptibility to both azole antifungal and cell wall-damaging agents and was also attenuated in virulence. Although a mutant lacking the downstream transcription factor Crz1 displayed a cell wall-associated phenotype intermediate to that of the calcineurin mutant and was modestly attenuated in virulence, it did not show increased azole susceptibility. These results suggest that calcineurin regulates both Crz1-dependent and -independent pathways depending on the type of stress.
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Affiliation(s)
- Taiga Miyazaki
- Department of Molecular Microbiology and Immunology, Nagasaki University School of Medicine, 1-7-1 Sakamoto, Nagasaki 852-8501, Japan.
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Soriani FM, Malavazi I, Savoldi M, Espeso E, Dinamarco TM, Bernardes LAS, Ferreira MES, Goldman MHS, Goldman GH. Identification of possible targets of the Aspergillus fumigatus CRZ1 homologue, CrzA. BMC Microbiol 2010; 10:12. [PMID: 20078882 PMCID: PMC2818617 DOI: 10.1186/1471-2180-10-12] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2009] [Accepted: 01/15/2010] [Indexed: 11/13/2022] Open
Abstract
Background Calcineurin, a serine/threonine-specific protein phosphatase, plays an important role in the control of cell morphology and virulence in fungi. Calcineurin regulates localization and activity of a transcription factor called CRZ1. Recently, we characterize Aspergillus fumigatus CRZ1 homologue, AfCrzA. Here, we investigate which pathways are influenced by A. fumigatus AfCrzA during a short pulse of calcium by comparatively determining the transcriptional profile of A. fumigatus wild type and ΔAfcrzA mutant strains. Results We were able to observe 3,622 genes modulated in at least one timepoint in the mutant when compared to the wild type strain (3,211 and 411 at 10 and 30 minutes, respectively). Decreased mRNA abundance in the ΔcrzA was seen for genes encoding calcium transporters, transcription factors and genes that could be directly or indirectly involved in calcium metabolism. Increased mRNA accumulation was observed for some genes encoding proteins involved in stress response. AfCrzA overexpression in A. fumigatus increases the expression of several of these genes. The deleted strain of one of these genes, AfRcnA, belonging to a class of endogenous calcineurin regulators, calcipressins, had more calcineurin activity after exposure to calcium and was less sensitive to menadione 30 μM, hydrogen peroxide 2.5 mM, EGTA 25 mM, and MnCl2 25 mM. We constructed deletion, overexpression, and GFP fusion protein for the closely related A. nidulans AnRcnA. GFP::RcnA was mostly detected along the germling, did not accumulate in the nuclei and its location is not affected by the cellular response to calcium chloride. Conclusion We have performed a transcriptional profiling analysis of the A. fumigatus ΔAfcrzA mutant strain exposed to calcium stress. This provided an excellent opportunity to identify genes and pathways that are under the influence of AfCrzA. AfRcnA, one of these selected genes, encodes a modulator of calcineurin activity. Concomitantly with A. fumigatus AfrcnA molecular analysis, we decided to exploit the conserved features of A. nidulans calcineurin system and investigated the A. nidulans AnRcnA homologue. A. nidulans AnRcnA mutation is suppressing CnaA mutation and it is responsible for modulating the calcineurin activity and mRNA accumulation of genes encoding calcium transporters.
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Affiliation(s)
- Frederico M Soriani
- Centro de Ciência e Tecnologia do Bioetanol and Faculdade de Ciências Farmacêuticas de Ribeirão Preto Universidade de São Paulo, São Paulo, Ribeirão Preto 14040-903, Brazil
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Elucidating the Candida albicans calcineurin signaling cascade controlling stress response and virulence. Fungal Genet Biol 2009; 47:107-16. [PMID: 19755168 DOI: 10.1016/j.fgb.2009.09.002] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2009] [Revised: 08/31/2009] [Accepted: 09/09/2009] [Indexed: 11/24/2022]
Abstract
The protein phosphatase calcineurin is a key mediator of virulence and antifungal susceptibility of multiple fungal pathogens including Candida albicans, Cryptococcus neoformans, and Aspergillus fumigatus, and has clinical potential as a therapeutic target to increase the efficacy of the current antifungal armamentarium. Despite the importance of this signaling pathway, few components of the calcineurin-signaling pathway are known in C. albicans. Here we identified and analyzed additional components of the C. albicans calcineurin cascade, including the RCN1 (regulator of calcineurin1), MID1, and CCH1 genes, which mediate calcineurin functions in other species. When heterologously expressed in Saccharomyces cerevisiae, C. albicans Rcn1 inhibited calcineurin function. Although rcn1/rcn1, mid1/mid1, and cch1/cch1 mutant strains share some phenotypes with calcineurin mutants, they do not completely recapitulate the phenotypes of a calcineurin mutant strain. These studies extend our understanding of the C. albicans calcineurin signaling cascade and its host-niche specific role in virulence.
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Lenardon MD, Lesiak I, Munro CA, Gow NAR. Dissection of the Candida albicans class I chitin synthase promoters. Mol Genet Genomics 2009; 281:459-71. [PMID: 19153767 PMCID: PMC3468743 DOI: 10.1007/s00438-009-0423-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2008] [Accepted: 01/05/2009] [Indexed: 11/24/2022]
Abstract
Maintenance of the integrity of the cell wall in fungi is essential. One mechanism that cells use to maintain cell wall integrity in response to cell wall damage is to up-regulate chitin synthesis. In Candida albicans, the PKC cell wall integrity, Ca(2+)/calcineurin and high osmolarity glycerol (HOG) signalling pathways co-ordinately regulate chitin synthesis in response to cell wall stress. The transcription factors downstream of these pathways and their DNA binding sites within the promoters of target genes are well characterised in Saccharomyces cerevisiae, but not in C. albicans. The promoters of the C. albicans class I CHS genes (CaCHS2 and CaCHS8) were functionally dissected with the aim of identifying and characterising the transcription factors and promoter elements that mediate the transcriptional up-regulation of CaCHS2 and CaCHS8 in response to cell wall stress. This analysis provided evidence that the PKC cell wall integrity pathway may operate through RLM1-elements in the CaCHS2 and CaCHS8 promoters, but that promoter sequences that respond to the Ca(2+)/calcineurin and HOG signalling pathways in S. cerevisiae did not directly regulate chitin synthase 2 and 8 gene transcription in C. albicans.
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Affiliation(s)
- Megan D. Lenardon
- School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD Scotland, UK
| | - Iwona Lesiak
- Present Address: Department for Hygiene, Microbiology and Social Medicine, Innsbruck Medical University, Fritz-Preglstr. 3, 6020 Innsbruck, Austria
| | - Carol A. Munro
- School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD Scotland, UK
| | - Neil A. R. Gow
- School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD Scotland, UK
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Choi J, Kim Y, Kim S, Park J, Lee YH. MoCRZ1, a gene encoding a calcineurin-responsive transcription factor, regulates fungal growth and pathogenicity of Magnaporthe oryzae. Fungal Genet Biol 2008; 46:243-54. [PMID: 19111943 DOI: 10.1016/j.fgb.2008.11.010] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2008] [Revised: 11/18/2008] [Accepted: 11/27/2008] [Indexed: 11/30/2022]
Abstract
Ca(2+)-dependent signaling plays important roles in cellular development and metabolism in fungi. Pharmacological and molecular evidence clearly indicates that Ca(2+)-dependent signaling is required for infection-related development and pathogenicity in the rice blast fungus Magnaporthe oryzae. However, little information is available on downstream regulators in the Ca(2+)-dependent signaling pathway. To understand the role of a calcineurin-dependent transcription factor in the rice blast fungus, an ortholog of Saccharomyces cerevisiae CRZ1 in M. oryzae, MoCRZ1, was identified and functionally characterized. The Deltamocrz1 mutant exhibited impaired growth in the presence of Ca(2+) ions or cell wall perturbing agents. The Deltamocrz1 mutant also showed reduced conidiation and reduced pathogenicity, which is mainly due to a defect in host penetration. MoCRZ1 fused to EGFP was trans-localized into the nucleus in a Ca(2+)/calcineurin-dependent manner. The MoCRZ1 gene is also required for the calcineurin-dependent transcriptional induction of FKS1, a gene encoding a beta-1,3 glucan synthase, CHS2 and CHS4, genes encoding two chitin synthases, and PMC and PMR gene families encoding P-type ATPases in response to Ca(2+). These results suggest that MoCRZ1 is a downstream regulator in Ca(2+)-dependent signaling for pathogenicity in M. oryzae, and its biochemical mechanisms are well conserved among fungal species.
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Affiliation(s)
- Jinhee Choi
- Department of Agricultural Biotechnology, Center for Fungal Genetic Resources, Seoul National University, Seoul, South Korea
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Nonapoptotic death of Saccharomyces cerevisiae cells that is stimulated by Hsp90 and inhibited by calcineurin and Cmk2 in response to endoplasmic reticulum stresses. EUKARYOTIC CELL 2008; 7:2037-51. [PMID: 18806210 DOI: 10.1128/ec.00291-08] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Endoplasmic reticulum (ER) stress can trigger apoptosis and necrosis in many types of mammalian cells. Previous studies in yeast found little or no cell death in response to the ER stressor tunicamycin, but a recent study suggested widespread apoptosis-like death. Here we show that wild-type laboratory Saccharomyces cerevisiae cells responding to tunicamycin die by nonapoptotic mechanisms in low-osmolyte culture media and survive for long periods of time in standard synthetic media. Survival requires calcineurin, a Ca(2+)/calmodulin-dependent protein phosphatase, but none of its known targets. The Ca(2+)/calmodulin-dependent protein kinase Cmk2 was identified as an indirect target of calcineurin that suppresses death of calcineurin-deficient cells. Death of Cmk2- and/or calcineurin-deficient S. cerevisiae cells was preceded by accumulation of reactive oxygen species but was not associated with hallmarks of apoptosis and was not dependent on Mca1, Aif1, Nuc1, or other factors implicated in apoptosis-like death. Cmk2 and calcineurin also independently suppressed the death of S. cerevisiae cells responding to dithiothreitol or miconazole, a common azole-class antifungal drug. Though inhibitors of Hsp90 have been shown to diminish calcineurin signaling in S. cerevisiae and to synergistically inhibit growth in combination with azoles, they did not stimulate death of S. cerevisiae cells in combination with miconazole or tunicamycin, and instead they prevented the death of calcineurin- and Cmk2-deficient cells. These findings reveal a novel prodeath role for Hsp90 and antideath roles for calcineurin and Cmk2 that extend the life span of S. cerevisiae cells responding to both natural and clinical antifungal compounds.
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Ramsdale M, Selway L, Stead D, Walker J, Yin Z, Nicholls SM, Crowe J, Sheils EM, Brown AJP. MNL1 regulates weak acid-induced stress responses of the fungal pathogen Candida albicans. Mol Biol Cell 2008; 19:4393-403. [PMID: 18653474 DOI: 10.1091/mbc.e07-09-0946] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
MNL1, the Candida albicans homologue of an orphan Msn2-like gene (YER130c in Saccharomyces cerevisiae) has no known function. Here we report that MNL1 regulates weak acid stress responses. Deletion of MNL1 prevents the long-term adaptation of C. albicans cells to weak acid stresses and compromises their global transcriptional response under these conditions. The promoters of Mnl1-dependent genes contain a novel STRE-like element (SLE) that imposes Mnl1-dependent, weak acid stress-induced transcription upon a lacZ reporter in C. albicans. The SLE (HHYYCCCCTTYTY) is related to the Nrg1 response element (NRE) element recognized by the transcriptional repressor Nrg1. Deletion of NRG1 partially restores the ability of C. albicans mnl1 cells to adapt to weak acid stress, indicating that Mnl1 and Nrg1 act antagonistically to regulate this response. Molecular, microarray, and proteomic analyses revealed that Mnl1-dependent adaptation does not occur in cells exposed to proapoptotic or pronecrotic doses of weak acid, suggesting that Ras-pathway activation might suppress the Mnl1-dependent weak acid response in dying cells. Our work defines a role for this YER130c orthologue in stress adaptation and cell death.
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Affiliation(s)
- Mark Ramsdale
- Institute of Medical Sciences, School of Medical Sciences, Foresterhill, Aberdeen, AB25 2ZD, United Kingdom.
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Cramer RA, Perfect BZ, Pinchai N, Park S, Perlin DS, Asfaw YG, Heitman J, Perfect JR, Steinbach WJ. Calcineurin target CrzA regulates conidial germination, hyphal growth, and pathogenesis of Aspergillus fumigatus. EUKARYOTIC CELL 2008; 7:1085-97. [PMID: 18456861 PMCID: PMC2446674 DOI: 10.1128/ec.00086-08] [Citation(s) in RCA: 135] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2008] [Accepted: 04/17/2008] [Indexed: 11/20/2022]
Abstract
The calcineurin pathway is a critical signal transduction pathway in fungi that mediates growth, morphology, stress responses, and pathogenicity. The importance of the calcineurin pathway in fungal physiology creates an opportunity for the development of new antifungal therapies that target this critical signaling pathway. In this study, we examined the role of the zinc finger transcription factor Crz1 homolog (CrzA) in the physiology and pathogenicity of the opportunistic human fungal pathogen Aspergillus fumigatus. Genetic replacement of the crzA locus in A. fumigatus resulted in a strain with significant defects in conidial germination, polarized hyphal growth, cell wall structure, and asexual development that are similar to but with differences from defects seen in the A. fumigatus DeltacnaA (calcineurin A) strain. Like the DeltacnaA strain, the DeltacrzA strain was incapable of causing disease in an experimental persistently neutropenic inhalational murine model of invasive pulmonary aspergillosis. Our results suggest that CrzA is an important downstream effector of calcineurin that controls morphology in A. fumigatus, but additional downstream effectors that mediate calcineurin signal transduction are likely present in this opportunistic fungal pathogen. In addition, the importance of CrzA to the production of disease is critical, and thus CrzA is an attractive fungus-specific antifungal target for the treatment of invasive aspergillosis.
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Affiliation(s)
- Robert A Cramer
- Duke University Medical Center, Box 3499, Pediatric Infectious Diseases, Durham, NC 27710, USA
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Stress, drugs, and evolution: the role of cellular signaling in fungal drug resistance. EUKARYOTIC CELL 2008; 7:747-64. [PMID: 18375617 DOI: 10.1128/ec.00041-08] [Citation(s) in RCA: 207] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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