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Jiang Q, Mao R, Li Y, Bi Y, Liu Y, Zhang M, Li R, Yang Y, Dov B P.
AaCaM
is required for infection structure differentiation and secondary metabolites in pear fungal pathogen
Alternaria alternata. J Appl Microbiol 2022; 133:2631-2641. [DOI: 10.1111/jam.15732] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 06/12/2022] [Accepted: 07/20/2022] [Indexed: 11/29/2022]
Affiliation(s)
- Qianqian Jiang
- College of Food Science and Engineering Gansu Agricultural University Lanzhou China
| | - Renyan Mao
- College of Food Science and Engineering Gansu Agricultural University Lanzhou China
| | - Yongcai Li
- College of Food Science and Engineering Gansu Agricultural University Lanzhou China
| | - Yang Bi
- College of Food Science and Engineering Gansu Agricultural University Lanzhou China
| | - Yongxiang Liu
- College of Food Science and Engineering Gansu Agricultural University Lanzhou China
| | - Miao Zhang
- College of Food Science and Engineering Gansu Agricultural University Lanzhou China
| | - Rong Li
- College of Food Science and Engineering Gansu Agricultural University Lanzhou China
| | - Yangyang Yang
- College of Food Science and Engineering Gansu Agricultural University Lanzhou China
| | - Prusky Dov B
- College of Food Science and Engineering Gansu Agricultural University Lanzhou China
- Institute of Postharvest and Food Sciences The Volcani Center, Agricultural Research Organization Rishon LeZion Israel
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Cellular Calcium Levels Influenced by NCA-2 Impact Circadian Period Determination in Neurospora. mBio 2021; 12:e0149321. [PMID: 34182778 PMCID: PMC8262947 DOI: 10.1128/mbio.01493-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Intracellular calcium signaling has been implicated in the control of a variety of circadian processes in animals and plants, but its role in microbial clocks has remained largely cryptic. To examine the role of intracellular Ca2+ in the Neurospora clock, we screened mutants with knockouts of calcium transporter genes and identified a gene encoding a calcium exporter, nca-2, uniquely as having significant period effects. The loss of NCA-2 results in an increase in the cytosolic calcium level, and this leads to hyper-phosphorylation of core clock components, FRQ and WC-1, and a short period, as measured by both the core oscillator and the overt clock. Genetic analyses showed that mutations in certain frq phospho-sites and in Ca2+-calmodulin-dependent kinase 2 (camk-2) are epistatic to nca-2 in controlling the pace of the oscillator. These data are consistent with a model in which elevated intracellular Ca2+ leads to the increased activity of CAMK-2, leading to enhanced FRQ phosphorylation, accelerated closure of the circadian feedback loop, and a shortened circadian period length. At a mechanistic level, some CAMKs undergo more auto-phosphorylations in the Δnca-2 mutant, consistent with high calcium levels in the Δnca-2 mutant influencing the enzymatic activities of CAMKs. NCA-2 interacts with multiple proteins, including CSP-6, a protein known to be required for circadian output. Most importantly, the expression of nca-2 is circadian clock-controlled at both the transcriptional and translational levels, and this in combination with the period effects seen in strains lacking NCA-2 firmly places calcium signaling within the larger circadian system, where it acts as both an input to and an output from the core clock.
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Shishodia SK, Tiwari S, Hoda S, Vijayaraghavan P, Shankar J. SEM and qRT-PCR revealed quercetin inhibits morphogenesis of Aspergillus flavus conidia via modulating calcineurin-Crz1 signalling pathway. Mycology 2020; 11:118-125. [PMID: 32923020 PMCID: PMC7448844 DOI: 10.1080/21501203.2020.1711826] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 12/29/2019] [Indexed: 12/02/2022] Open
Abstract
ASPERGILLUS FLAVUS exploits diverse mechanisms to survive during exposure to antifungal agents including morphogenesis. Germination of dormant conidia involves cascades of reactions integrated into the signalling pathway. This study documents the effect of phytochemical-quercetin on A. flavus during germination of conidia using scanning electron microscopy (SEM). Significant inhibition of conidial swelling of A. flavus in comparison to control was observed at 4 and 7 h Quantitative real-time PCR for genes from calcium signalling pathway and heat-shock proteins family showed up-regulation of heat shock (Hsp70 and Hsp90) and calcium signalling pathway genes (calcium-transporting ATPase and calmodulin) in response to quercetin at initial 4 h in comparison to control sample whereas up-regulation of Hsp70, calcineurin and transcription factor Crz1, were observed in both the treated samples. Gene encoding for calcium-kinase, cAMP, Rho-gdp, Plc and Pkc showed a constitutively higher level of expression in quercetin-treated sample in comparison to control at both time points. These data showed a clear response from genes encoding calcineurin-Crz1 signalling pathways and may find its application in the screening of antifungal agents. ABBREVIATIONS Hsp: Hear shock protein; MIC: Minimum Inhibitory Concentration; SEM: Scanning Electron Microscopy; qRT-PCR: Quantitative Real-Time Polymerase Chain Reaction.
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Affiliation(s)
- Sonia K. Shishodia
- Genomics laboratory, Department of Biotechnology and Bioinformatics, Jaypee University of Information Technology, Solan, India
| | - Shraddha Tiwari
- Genomics laboratory, Department of Biotechnology and Bioinformatics, Jaypee University of Information Technology, Solan, India
| | - Shanu Hoda
- Amity Institute of Biotechnology, Amity University Uttar Pradesh, Noida, India
| | | | - Jata Shankar
- Genomics laboratory, Department of Biotechnology and Bioinformatics, Jaypee University of Information Technology, Solan, India
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Ren XX, Wang Y, Liu Y, Tan Y, Ren C, Ge Y, Liu Z. Comparative transcriptome analysis of the calcium signaling and expression analysis of sodium/calcium exchanger in Aspergillus cristatus. J Basic Microbiol 2017; 58:76-87. [PMID: 29152764 DOI: 10.1002/jobm.201700277] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Revised: 07/20/2017] [Accepted: 09/19/2017] [Indexed: 01/26/2023]
Abstract
Aspergillus cristatus develops into various stages under different Na concentrations: the sexual stage in 0.5 M NaCl and asexual development stage in 3 M NaCl. In order to explore whether the Ca2+ signaling pathway in A. cristatus responded to the changes in the salt stress, we analyzed the gene expression levels in A. cristatus respectively cultured in 0.5 M NaCl and 3 M NaCl. According to the BLAST analysis results, we identified 25 Ca2+ -signaling proteins in A. cristatus. The expression levels of most genes involved in the Ca2+ -signaling pathway in A. cristatus cultured in different salt concentrations showed significant differences, indicating that the Ca2+ signaling pathway was involved in the response to the changes in the salt stress. In yeasts, only calcium ion influx proteins were reported to be involved in the response to the changes in the salt stress. So far, the protein for the exchanger of calcium/sodium ions has not been reported. Therefore, we obtained the sodium/calcium exchanger (termed NCX) proteins from the KEGG Database. The ncx gene of A. cristatus was cloned and characterized. The full length of ncx gene is 3055 bp, including a 2994-bp open reading frame encoding 994 amino acids. The expression levels of ncx in the sexual development stage and asexual development stage were respectively ∼8.94 times and ∼2.57 times of that in the hyphal formation stage. Therefore, we suggested that ncx gene was up-regulated to resist the sodium stress. The study results provide the basis for further exploring the Ca2+ -signaling mechanism and ion exchanger mechanism.
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Affiliation(s)
- Xiu-Xiu Ren
- College of Agriculture, Guizhou University, Guiyang, PR China.,College of Ecological Engineering, Guizhou University of Engineering Science, Bijie, PR China
| | - Yuchen Wang
- Guizhou Academy of Agricultural Sciences, Guiyang, PR China
| | - YongXiang Liu
- Guizhou Academy of Agricultural Sciences, Guiyang, PR China
| | - Yumei Tan
- Guizhou Academy of Agricultural Sciences, Guiyang, PR China
| | - Chunguang Ren
- Guizhou Academy of Agricultural Sciences, Guiyang, PR China
| | - Yongyi Ge
- Guizhou Academy of Agricultural Sciences, Guiyang, PR China
| | - Zuoyi Liu
- Guizhou Academy of Agricultural Sciences, Guiyang, PR China
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Muñoz A, Chu M, Marris PI, Sagaram US, Kaur J, Shah DM, Read ND. Specific domains of plant defensins differentially disrupt colony initiation, cell fusion and calcium homeostasis inNeurospora crassa. Mol Microbiol 2014; 92:1357-74. [DOI: 10.1111/mmi.12634] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/28/2014] [Indexed: 12/14/2022]
Affiliation(s)
- Alberto Muñoz
- Fungal Cell Biology Group; Institute of Cell Biology; University of Edinburgh; Edinburgh EH9 3JH UK
- Manchester Fungal Infection Group; Institute of Inflammation and Repair; CTF Building; University of Manchester; Manchester M13 9NT UK
| | - Meiling Chu
- Fungal Cell Biology Group; Institute of Cell Biology; University of Edinburgh; Edinburgh EH9 3JH UK
| | - Peter I. Marris
- Fungal Cell Biology Group; Institute of Cell Biology; University of Edinburgh; Edinburgh EH9 3JH UK
| | - Uma S. Sagaram
- Donald Danforth Plant Science Center; St Louis MO 63132 USA
| | - Jagdeep Kaur
- Donald Danforth Plant Science Center; St Louis MO 63132 USA
| | - Dilip M. Shah
- Donald Danforth Plant Science Center; St Louis MO 63132 USA
| | - Nick D. Read
- Fungal Cell Biology Group; Institute of Cell Biology; University of Edinburgh; Edinburgh EH9 3JH UK
- Manchester Fungal Infection Group; Institute of Inflammation and Repair; CTF Building; University of Manchester; Manchester M13 9NT UK
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6
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Panina S, Stephan A, la Cour JM, Jacobsen K, Kallerup LK, Bumbuleviciute R, Knudsen KVK, Sánchez-González P, Villalobo A, Olesen UH, Berchtold MW. Significance of calcium binding, tyrosine phosphorylation, and lysine trimethylation for the essential function of calmodulin in vertebrate cells analyzed in a novel gene replacement system. J Biol Chem 2012; 287:18173-81. [PMID: 22493455 DOI: 10.1074/jbc.m112.339382] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Calmodulin (CaM) was shown to be essential for survival of lower eukaryotes by gene deletion experiments. So far, no CaM gene deletion was reported in higher eukaryotes. In vertebrates, CaM is expressed from several genes, which encode an identical protein, making it difficult to generate a model system to study the effect of CaM gene deletion. Here, we present a novel genetic system based on the chicken DT40 cell line, in which the two functional CaM genes were deleted and one allele replaced with a CaM transgene that can be artificially regulated. We show that CaM is essential for survival of vertebrate cells as they die in the absence of CaM expression. Reversal of CaM repression or ectopic expression of HA-tagged CaM rescued the cells. Cells exclusively expressing HA-CaM with impaired individual calcium binding domains as well as HA-CaM lacking the ability to be phosphorylated at residues Tyr(99)/Tyr(138) or trimethylated at Lys(115) survived and grew well. CaM mutated at both Ca(2+) binding sites 3 and 4 as well as at both sites 1 and 2, but to a lesser degree, showed decreased ability to support cell growth. Cells expressing CaM with all calcium binding sites impaired died with kinetics similar to that of cells expressing no CaM. This system offers a unique opportunity to analyze CaM structure-function relationships in vivo without the use of pharmacological inhibitors and to analyze the function of wild type and mutated CaM in modulating the activity of different target systems without interference of endogenous CaM.
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Affiliation(s)
- Svetlana Panina
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
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Gao L, Song Y, Cao J, Wang S, Wei H, Jiang H, Lu L. Osmotic stabilizer-coupled suppression of NDR defects is dependent on the calcium-calcineurin signaling cascade in Aspergillus nidulans. Cell Signal 2011; 23:1750-7. [PMID: 21741477 DOI: 10.1016/j.cellsig.2011.06.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2011] [Revised: 06/03/2011] [Accepted: 06/15/2011] [Indexed: 11/18/2022]
Abstract
Establishment and maintenance of cell polarity are coordinated by signaling pathways such as NDR (nuclear Dbf2-related) protein-kinase signaling and calcium signaling pathway. The NDR family of kinase is structurally related to the human myotonic dystrophy kinase, which, when impaired, confers a disease that involves changes in cytoarchitecture and ion homeostasis. CotA kinase, a member of the NDR protein kinase family, forms a complex with MobB to regulate cell polarized growth in Aspergillus nidulans. Our previous study demonstrated that mobB/cotA defects could be suppressed by the osmotic stress in the presence of external calcium. In this study, via the genetic and molecular approach, we further demonstrated that Ca(2+)-permeable stretch-activated nonselective cation channel-MidA, calcium/calmodulin-dependent protein phosphatase catalatic subunit-CnaA and external calcium, but not voltage-gated calcium channel homolog-CchA, were required for the osmotic stabilizer-coupled suppression. The up-regulation of calcium/calcineurin signaling pathway induced by osmotic stress might be the reason for bypassing the requirements of NDR kinase complex, which is otherwise necessary for polar morphogenesis. Our results suggest that calcium-calcineurin signaling pathway coordinates with MobB/CotA kinase complex in regulating polarity growth via maintaining cellular calcium homeostasis. However, CchA may act differently as other components in calcium signaling pathway in Aspergillus nidulans. These findings provide an excellent opportunity to identify the potential pathway linking NDR protein-kinase network to calcium signaling pathway.
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Affiliation(s)
- Lina Gao
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing, 210046, China
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Tamuli R, Kumar R, Deka R. Cellular roles of neuronal calcium sensor-1 and calcium/calmodulin-dependent kinases in fungi. J Basic Microbiol 2010; 51:120-8. [PMID: 21077122 DOI: 10.1002/jobm.201000184] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2010] [Accepted: 08/03/2010] [Indexed: 11/07/2022]
Abstract
The neuronal calcium sensor-1 (NCS-1) possesses a consensus signal for N-terminal myristoylation and four EF-hand Ca(2+)-binding sites, and mediates the effects of cytosolic Ca(2+). Minute changes in free intracellular Ca(2+) are quickly transformed into changes in the activity of several kinases including calcium/calmodulin-dependent protein kinases (Ca(2+)/CaMKs) that are involved in regulating many eukaryotic cell functions. However, our current knowledge of NCS-1 and Ca(2+)/CaMKs comes mostly from studies of the mammalian enzymes. Thus far very few fungal homologues of NCS-1 and Ca(2+)/CaMKs have been characterized and little is known about their cellular roles. In this minireview, we describe the known sequences, interactions with target proteins and cellular roles of NCS-1 and Ca(2+)/CaMKs in fungi.
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Affiliation(s)
- Ranjan Tamuli
- Department of Biotechnology, Indian Institute of Technology Guwahati, Guwahati, India.
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The antifungal activity of the Penicillium chrysogenum protein PAF disrupts calcium homeostasis in Neurospora crassa. EUKARYOTIC CELL 2010; 9:1374-82. [PMID: 20622001 DOI: 10.1128/ec.00050-10] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The antifungal protein PAF from Penicillium chrysogenum exhibits growth-inhibitory activity against a broad range of filamentous fungi. Evidence from this study suggests that disruption of Ca(2+) signaling/homeostasis plays an important role in the mechanistic basis of PAF as a growth inhibitor. Supplementation of the growth medium with high Ca(2+) concentrations counteracted PAF toxicity toward PAF-sensitive molds. By using a transgenic Neurospora crassa strain expressing codon-optimized aequorin, PAF was found to cause a significant increase in the resting level of cytosolic free Ca(2+) ([Ca(2+)](c)). The Ca(2+) signatures in response to stimulation by mechanical perturbation or hypo-osmotic shock were significantly changed in the presence of PAF. BAPTA [bis-(aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid], a Ca(2+) selective chelator, ameliorated the PAF toxicity in growth inhibition assays and counteracted PAF induced perturbation of Ca(2+) homeostasis. These results indicate that extracellular Ca(2+) was the major source of these PAF-induced effects. The L-type Ca(2+) channel blocker diltiazem disrupted Ca(2+) homeostasis in a similar manner to PAF. Diltiazem in combination with PAF acted additively in enhancing growth inhibition and accentuating the change in Ca(2+) signatures in response to external stimuli. Notably, both PAF and diltiazem increased the [Ca(2+)](c) resting level. However, experiments with an aequorin-expressing Deltacch-1 deletion strain of N. crassa indicated that the L-type Ca(2+) channel CCH-1 was not responsible for the observed PAF-induced elevation of the [Ca(2+)](c) resting level. This study is the first demonstration of the perturbation of fungal Ca(2+) homeostasis by an antifungal protein from a filamentous ascomycete and provides important new insights into the mode of action of PAF.
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Chen S, Song Y, Cao J, Wang G, Wei H, Xu X, Lu L. Localization and function of calmodulin in live-cells of Aspergillus nidulans. Fungal Genet Biol 2010; 47:268-78. [DOI: 10.1016/j.fgb.2009.12.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2009] [Revised: 10/29/2009] [Accepted: 12/17/2009] [Indexed: 10/20/2022]
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Xiong LW, Kleerekoper QK, Wang X, Putkey JA. Intra- and interdomain effects due to mutation of calcium-binding sites in calmodulin. J Biol Chem 2010; 285:8094-103. [PMID: 20048169 DOI: 10.1074/jbc.m109.065243] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The IQ-motif protein PEP-19, binds to the C-domain of calmodulin (CaM) with significantly different k(on) and k(off) rates in the presence and absence of Ca(2+), which could play a role in defining the levels of free CaM during Ca(2+) transients. The initial goal of the current study was to determine whether Ca(2+) binding to sites III or IV in the C-domain of CaM was responsible for affecting the kinetics of binding PEP-19. EF-hand Ca(2+)-binding sites were selectively inactivated by the common strategy of changing Asp to Ala at the X-coordination position. Although Ca(2+) binding to both sites III and IV appeared necessary for native-like interactions with PEP-19, the data also indicated that the mutations caused undesirable structural alterations as evidenced by significant changes in amide chemical shifts for apoCaM. Mutations in the C-domain also affected chemical shifts in the unmodified N-domain, and altered the Ca(2+) binding properties of the N-domain. Conversion of Asp(93) to Ala caused the greatest structural perturbations, possibly due to the loss of stabilizing hydrogen bonds between the side chain of Asp(93) and backbone amides in apo loop III. Thus, although these mutations inhibit binding of Ca(2+), the mutated CaM may not be able to support potentially important native-like activity of the apoprotein. This should be taken into account when designing CaM mutants for expression in cell culture.
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Affiliation(s)
- Liang-Wen Xiong
- Department of Biochemistry and Molecular Biology and the Structural Biology Center, University of Texas, Houston Medical School, Houston, Texas 77030, USA
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Aspergillus parasiticus crzA, which encodes calcineurin response zinc-finger protein, is required for aflatoxin production under calcium stress. Int J Mol Sci 2008; 9:2027-2043. [PMID: 19325734 PMCID: PMC2635607 DOI: 10.3390/ijms9102027] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2008] [Revised: 10/27/2008] [Accepted: 10/28/2008] [Indexed: 11/17/2022] Open
Abstract
Two morphologically different Aspergillus parasiticus strains, one producing aflatoxins, abundant conidia but few sclerotia (BN9) and the other producing O-methyl-sterimatocystin (OMST), copious sclerotia but a low number of conidia (RH), were used to assess the role of crzA which encodes a putative calcium-signaling pathway regulatory protein. Under standard culture conditions, BN9ΔcrzA mutants conidiated normally but decreased slightly in radial growth, regardless of illumination conditions. RHΔcrzA mutants produced only conidia under light and showed decreased conidiation and delayed sclerotial formation in the dark. Regulation of conidiation of both A. parasiticus strains by light was independent of crzA. Increased concentrations of lithium, sodium, and potassium impaired conidiation and sclerotial formation of the RHΔcrzA mutants but they did not affect conidiation of the BN9ΔcrzA mutants. Vegetative growth and asexual development of both ΔcrzA mutants were hypersensitive to increased calcium concentrations. Calcium supplementation (10 mM) resulted in 3-fold and 2-fold decreases in the relative expression of the endoplasmic reticulum calcium ATPase 2 gene in the BN9 and RH parental strains, respectively, but changes in both ΔcrzA mutants were less significant. Compared to the parental strains, the ΔcrzA mutants barely produced aflatoxins or OMST after the calcium supplementation. The relative expression levels of aflatoxin biosynthesis genes, nor1, ver1, and omtA, in both ΔcrzA mutants were decreased significantly, but the decreases in the parental strains were at much lower extents. CrzA is required for growth and development and for aflatoxin biosynthesis under calcium stress conditions.
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Nguyen QB, Kadotani N, Kasahara S, Tosa Y, Mayama S, Nakayashiki H. Systematic functional analysis of calcium-signalling proteins in the genome of the rice-blast fungus, Magnaporthe oryzae, using a high-throughput RNA-silencing system. Mol Microbiol 2008; 68:1348-65. [PMID: 18433453 DOI: 10.1111/j.1365-2958.2008.06242.x] [Citation(s) in RCA: 153] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We developed an RNA-silencing vector, pSilent-Dual1 (pSD1), with a convergent dual promoter system that provides a high-throughput platform for functional genomics research in filamentous fungi. In the pSD1 system, the target gene was designed to be transcribed as a chimeric RNA with enhanced green fluorescent protein (eGFP) RNA. This enabled us to efficiently screen the resulting transformants using GFP fluorescence as an indicator of gene silencing. A model study with the eGFP gene showed that pSD1-based vectors induced gene silencing via the RNAi pathway with slightly lower efficiency than did hairpin eGFP RNA-expressing vectors. To demonstrate the applicability of the pSD1 system for elucidating gene function in the rice-blast fungus Magnaporthe oryzae, 37 calcium signalling-related genes that include almost all known calcium-signalling proteins in the genome were targeted for gene silencing by the vector. Phenotypic analyses of the silenced transformants showed that at least 26, 35 and 15 of the 37 genes examined were involved in hyphal growth, sporulation and pathogenicity, respectively, in M. oryzae. These included several novel findings such as that Pmc1-, Spf1- and Neo1-like Ca(2+) pumps, calreticulin and calpactin heavy chain were essential for fungal pathogenicity.
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Affiliation(s)
- Quoc Bao Nguyen
- Laboratory of Plant Pathology, Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodaicho, Nada, Kobe, Japan
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Valle-Aviles L, Valentin-Berrios S, Gonzalez-Mendez RR, Rodriguez-Del Valle N. Functional, genetic and bioinformatic characterization of a calcium/calmodulin kinase gene in Sporothrix schenckii. BMC Microbiol 2007; 7:107. [PMID: 18047672 PMCID: PMC2242797 DOI: 10.1186/1471-2180-7-107] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2007] [Accepted: 11/29/2007] [Indexed: 11/17/2022] Open
Abstract
Background Sporothrix schenckii is a pathogenic, dimorphic fungus, the etiological agent of sporotrichosis, a subcutaneous lymphatic mycosis. Dimorphism in S. schenckii responds to second messengers such as cAMP and calcium, suggesting the possible involvement of a calcium/calmodulin kinase in its regulation. In this study we describe a novel calcium/calmodulin-dependent protein kinase gene in S. schenckii, sscmk1, and the effects of inhibitors of calmodulin and calcium/calmodulin kinases on the yeast to mycelium transition and the yeast cell cycle. Results Using the PCR homology approach a new member of the calcium/calmodulin kinase family, SSCMK1, was identified in this fungus. The cDNA sequence of sscmk1 revealed an open reading frame of 1,221 nucleotides encoding a 407 amino acid protein with a predicted molecular weight of 45.6 kDa. The genomic sequence of sscmk1 revealed the same ORF interrupted by five introns. Bioinformatic analyses of SSCMK1 showed that this protein had the distinctive features that characterize a calcium/calmodulin protein kinase: a serine/threonine protein kinase domain and a calmodulin-binding domain. When compared to homologues from seven species of filamentous fungi, SSCMK1 showed substantial similarities, except for a large and highly variable region that encompasses positions 330 – 380 of the multiple sequence alignment. Inhibition studies using calmodulin inhibitor W-7, and calcium/calmodulin kinase inhibitors, KN-62 and lavendustin C, were found to inhibit budding by cells induced to re-enter the yeast cell cycle and to favor the yeast to mycelium transition. Conclusion This study constitutes the first evidence of the presence of a calcium/calmodulin kinase-encoding gene in S. schenckii and its possible involvement as an effector of dimorphism in this fungus. These results suggest that a calcium/calmodulin dependent signaling pathway could be involved in the regulation of dimorphism in this fungus. The results suggest that the calcium/calmodulin kinases of yeasts are evolutionarily distinct from those in filamentous fungi.
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Affiliation(s)
- Liz Valle-Aviles
- Department of Microbiology and Medical Zoology, Medical Sciences Campus, University of Puerto Rico, PO Box 365067, San Juan, PR 00936-5067, USA.
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Vitale RG, Afeltra J, Meis JFGM, Verweij PE. Activity and post antifungal effect of chlorpromazine and trifluopherazine against Aspergillus, Scedosporium and zygomycetes. Mycoses 2007; 50:270-6. [PMID: 17576318 DOI: 10.1111/j.1439-0507.2007.01371.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The phenothiazine compounds chlorpromazine and trifluopherazine are antipsychotic agents that exhibit antimicrobial activity against bacteria, some protozoa and yeasts. Data of activity against filamentous fungi are lacking. The in vitro activity and postantifungal effect (PAFE) of chlorpromazine and trifluopherazine was determined against Aspergillus species, zygomycetes and Scedosporium species. In vitro susceptibility testing was performed with CLSI M38A and the PAFE was determined with previously established methods. Both drugs inhibited the growth of all fungi tested at concentrations of 16 to 64 microg ml(-1). For Aspergillus species the mean PAFE was 3.7 and 4.7 h; for zygomycetes, 3.1 and 3.4 h; for Scedosporium, 4.3 and 5.3 h for chlorpromazine and trifluoroperazine respectively. These are the first drugs shown to induce PAFE against Scedosporium. We show that phenothiazine compounds have in vitro antifungal activity and exhibit PAFE against a broad range of filamentous fungal pathogens. Although the exact mechanism of action is unknown, further studies are needed to explore the clinical usefulness of phenothiazine compounds.
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Affiliation(s)
- Roxana G Vitale
- Department of Medical Microbiology, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands
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Wang G, Lu L, Zhang CY, Singapuri A, Yuan S. Calmodulin concentrates at the apex of growing hyphae and localizes to the Spitzenkörper in Aspergillus nidulans. PROTOPLASMA 2006; 228:159-66. [PMID: 16983484 DOI: 10.1007/s00709-006-0181-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2005] [Accepted: 11/02/2005] [Indexed: 05/11/2023]
Abstract
The calmodulin (CaM) localization pattern in the growing hyphal tip of Aspergillus nidulans was studied with the functional GFP::CaM fusion protein. A faint tip-high gradient of CaM was found in the growing hyphal tip, with CaM highly localized in the region corresponding to the Spitzenkörper forming a bright granule. The position of highly concentrated CaM in the extreme apex seemed to determine the orientation of the hypha. The normal pattern of CaM localization was also shown to be dependent on the integrated actin cytoskeleton. When the growth of the hyphal tip ceased, CaM failed to localize in the bright granule and was evenly distributed in the hyphal tip. These findings suggest that CaM may play an important role in establishing and maintaining apical organization, morphogenesis, and growth in Aspergillus nidulans.
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Affiliation(s)
- G Wang
- Jiangsu Key Laboratory for Bioresource Technology, College of Life Science, Nanjing Normal University, Nanjing, People's Republic of China
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Kraus PR, Nichols CB, Heitman J. Calcium- and calcineurin-independent roles for calmodulin in Cryptococcus neoformans morphogenesis and high-temperature growth. EUKARYOTIC CELL 2005; 4:1079-87. [PMID: 15947200 PMCID: PMC1151996 DOI: 10.1128/ec.4.6.1079-1087.2005] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The function of calcium as a signaling molecule is conserved in eukaryotes from fungi to humans. Previous studies have identified the calcium-activated phosphatase calcineurin as a critical factor in governing growth of the human pathogenic fungus Cryptococcus neoformans at mammalian body temperature. Here, we employed insertional mutagenesis to identify new genes required for growth at 37 degrees C. One insertion mutant, cam1-ts, that displayed a growth defect at 37 degrees C and hypersensitivity to the calcineurin inhibitor FK506 at 25 degrees C was isolated. Both phenotypes were linked to the dominant marker in genetic crosses, and molecular analysis revealed that the insertion occurred in the 3' untranslated region of the gene encoding the calcineurin activator calmodulin (CAM1) and impairs growth at 37 degrees C by significantly reducing calmodulin mRNA abundance. The CAM1 gene was demonstrated to be essential using genetic analysis of a CAM1/cam1Delta diploid strain. In the absence of calcineurin function, the cam1-ts mutant displayed a severe morphological defect with impaired bud formation. Expression of a calmodulin-independent calcineurin mutant did not suppress the growth defect of the cam1-ts mutant at 37 degrees C, indicating that calmodulin promotes growth at high temperature via calcineurin-dependent and -independent pathways. In addition, a Ca2+-binding-defective allele of CAM1 complemented the 37 degrees C growth defect, FK506 hypersensitivity, and morphogenesis defect of the cam1-ts mutant. Our findings reveal that calmodulin performs Ca2+- and calcineurin-independent and -dependent roles in controlling C. neoformans morphogenesis and high-temperature growth.
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Affiliation(s)
- Peter R Kraus
- Department of Molecular Genetics and Microbiology, 322 CARL Building, Box 3546, Research Drive, Duke University Medical Center, Durham, NC 27710, USA
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Kraus PR, Heitman J. Coping with stress: calmodulin and calcineurin in model and pathogenic fungi. Biochem Biophys Res Commun 2004; 311:1151-7. [PMID: 14623301 DOI: 10.1016/s0006-291x(03)01528-6] [Citation(s) in RCA: 119] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Calcium signaling via calmodulin and calcineurin is critical for the regulation of stress responses in fungi. The functions of calmodulin and calcineurin are largely conserved among pathogenic fungi and model fungi, however, the mechanisms of action have diverged. Saccharomyces cerevisiae is an excellent model for understanding the framework of calcium-mediated signal transduction pathways, and considerable progress has been made in understanding the details of how Ca(2+)-calmodulin and calcineurin control adaptation to environmental stress. Studies using the divergent human pathogenic fungi Candida albicans and Cryptococcus neoformans reveal that calcineurin is critical for virulence, yet it acts via distinct mechanisms in each fungus. These differences in function may reflect the requirements of each pathogen to survive inside the host, and illustrate that studies must be conducted in each organism in order to elucidate the details of the molecular mechanisms of calmodulin and calcineurin-mediated signaling pathways.
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Affiliation(s)
- Peter R Kraus
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
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Abstract
Calcineurin is a Ca(2+)/calmodulin-activated protein phosphatase that is conserved in eukaryotes, from yeast to humans, and is the conserved target of the immunosuppressive drugs cyclosporin A (CsA) and FK506. Genetic studies in yeast and fungi established the molecular basis of calcineurin inhibition by the cyclophilin A-CsA and FKBP12-FK506 complexes. Calcineurin also functions in fungi to control a myriad of physiological processes including cell cycle progression, cation homeostasis, and morphogenesis. Recent investigations into the molecular mechanisms of pathogenesis in Candida albicans and Cryptococcus neoformans, two fungi that cause life-threatening infections in humans, have revealed an essential role for calcineurin in morphogenesis, virulence, and antifungal drug action. Novel non-immunosuppressive analogs of the calcineurin inhibitors CsA and FK506 that retain antifungal activity have been identified and hold promise as candidate antifungal drugs. In addition, comparisons of calcineurin function in both fungi and humans may identify fungal-specific components of calcineurin-signaling pathways that could be targeted for therapy, as well as conserved elements of calcium signaling events.
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Affiliation(s)
- Deborah S Fox
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
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