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Nickerson KW, Gutzmann DJ, Boone CHT, Pathirana RU, Atkin AL. Physiological adventures in Candida albicans: farnesol and ubiquinones. Microbiol Mol Biol Rev 2024; 88:e0008122. [PMID: 38436263 PMCID: PMC10966945 DOI: 10.1128/mmbr.00081-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/05/2024] Open
Abstract
SUMMARYFarnesol was first identified as a quorum-sensing molecule, which blocked the yeast to hyphal transition in Candida albicans, 22 years ago. However, its interactions with Candida biology are surprisingly complex. Exogenous (secreted or supplied) farnesol can also act as a virulence factor during pathogenesis and as a fungicidal agent triggering apoptosis in other competing fungi. Farnesol synthesis is turned off both during anaerobic growth and in opaque cells. Distinctly different cellular responses are observed as exogenous farnesol levels are increased from 0.1 to 100 µM. Reported changes include altered morphology, stress response, pathogenicity, antibiotic sensitivity/resistance, and even cell lysis. Throughout, there has been a dearth of mechanisms associated with these observations, in part due to the absence of accurate measurement of intracellular farnesol levels (Fi). This obstacle has recently been overcome, and the above phenomena can now be viewed in terms of changing Fi levels and the percentage of farnesol secreted. Critically, two aspects of isoprenoid metabolism present in higher organisms are absent in C. albicans and likely in other yeasts. These are pathways for farnesol salvage (converting farnesol to farnesyl pyrophosphate) and farnesylcysteine cleavage, a necessary step in the turnover of farnesylated proteins. Together, these developments suggest a unifying model, whereby high, threshold levels of Fi regulate which target proteins are farnesylated or the extent to which they are farnesylated. Thus, we suggest that the diversity of cellular responses to farnesol reflects the diversity of the proteins that are or are not farnesylated.
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Affiliation(s)
| | - Daniel J. Gutzmann
- School of Biological Sciences, University of Nebraska, Lincoln, Nebraska, USA
| | - Cory H. T. Boone
- School of Biological Sciences, University of Nebraska, Lincoln, Nebraska, USA
| | - Ruvini U. Pathirana
- Department of Biology and Chemistry, Texas A&M International University, Laredo, Texas, USA
| | - Audrey L. Atkin
- School of Biological Sciences, University of Nebraska, Lincoln, Nebraska, USA
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2
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Abstract
Quorum sensing (QS) is one of the most studied cell-cell communication mechanisms in fungi. Research in the last 20 years has explored various fungal QS systems that are involved in a wide range of biological processes, especially eukaryote- or fungus-specific behaviors, mirroring the significant contribution of QS regulation to fungal biology and evolution. Based on recent progress, we summarize in this review fungal QS regulation, with an emphasis on its functional role in behaviors unique to fungi or eukaryotes. We suggest that using fungi as genetically amenable eukaryotic model systems to address why and how QS regulation is integrated into eukaryotic reproductive strategies and molecular or cellular processes could be an important direction for QS research. Expected final online publication date for the Annual Review of Microbiology, Volume 75 is October 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Xiuyun Tian
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; .,University of Chinese Academy of Sciences, Beijing 100039, China
| | - Hao Ding
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; .,University of Chinese Academy of Sciences, Beijing 100039, China
| | - Weixin Ke
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; .,University of Chinese Academy of Sciences, Beijing 100039, China
| | - Linqi Wang
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; .,University of Chinese Academy of Sciences, Beijing 100039, China
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3
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Chelius C, Huso W, Reese S, Doan A, Lincoln S, Lawson K, Tran B, Purohit R, Glaros T, Srivastava R, Harris SD, Marten MR. Dynamic Transcriptomic and Phosphoproteomic Analysis During Cell Wall Stress in Aspergillus nidulans. Mol Cell Proteomics 2020; 19:1310-1329. [PMID: 32430394 PMCID: PMC8014999 DOI: 10.1074/mcp.ra119.001769] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 03/30/2020] [Indexed: 12/15/2022] Open
Abstract
The fungal cell-wall integrity signaling (CWIS) pathway regulates cellular response to environmental stress to enable wall repair and resumption of normal growth. This complex, interconnected, pathway has been only partially characterized in filamentous fungi. To better understand the dynamic cellular response to wall perturbation, a β-glucan synthase inhibitor (micafungin) was added to a growing A. nidulans shake-flask culture. From this flask, transcriptomic and phosphoproteomic data were acquired over 10 and 120 min, respectively. To differentiate statistically-significant dynamic behavior from noise, a multivariate adaptive regression splines (MARS) model was applied to both data sets. Over 1800 genes were dynamically expressed and over 700 phosphorylation sites had changing phosphorylation levels upon micafungin exposure. Twelve kinases had altered phosphorylation and phenotypic profiling of all non-essential kinase deletion mutants revealed putative connections between PrkA, Hk-8-4, and Stk19 and the CWIS pathway. Our collective data implicate actin regulation, endocytosis, and septum formation as critical cellular processes responding to activation of the CWIS pathway, and connections between CWIS and calcium, HOG, and SIN signaling pathways.
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Affiliation(s)
- Cynthia Chelius
- Department of Chemical, Biochemical, and Environmental Engineering, University of Maryland Baltimore County, Baltimore, Maryland, USA
| | - Walker Huso
- Department of Chemical, Biochemical, and Environmental Engineering, University of Maryland Baltimore County, Baltimore, Maryland, USA
| | - Samantha Reese
- Center for Plant Science Innovation and Department of Plant Pathology, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
| | - Alexander Doan
- Department of Chemical, Biochemical, and Environmental Engineering, University of Maryland Baltimore County, Baltimore, Maryland, USA
| | - Stephen Lincoln
- Department of Chemical and Biomolecular Engineering, University of Connecticut, Storrs, Connecticut, USA
| | - Kelsi Lawson
- Department of Chemical, Biochemical, and Environmental Engineering, University of Maryland Baltimore County, Baltimore, Maryland, USA
| | - Bao Tran
- BioScience Mass Spectrometry Facility, The U.S. Army CCDC Chemical Biological Center, BioSciences Division, Aberdeen Proving Ground, Maryland, USA
| | - Raj Purohit
- Department of Chemical, Biochemical, and Environmental Engineering, University of Maryland Baltimore County, Baltimore, Maryland, USA
| | - Trevor Glaros
- BioSciences Division, B11 Bioenergy and Biome Sciences, Los Alamos National Laboratory, Los Alamos, New Mexico, USA
| | - Ranjan Srivastava
- Department of Chemical and Biomolecular Engineering, University of Connecticut, Storrs, Connecticut, USA
| | - Steven D Harris
- Department of Biological Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Mark R Marten
- Department of Chemical, Biochemical, and Environmental Engineering, University of Maryland Baltimore County, Baltimore, Maryland, USA.
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4
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Nunes T, Cardoso P, Freitas R, Figueira E. Protective effects of farnesol on a Rhizobium strain exposed to cadmium. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2018; 165:622-629. [PMID: 30241090 DOI: 10.1016/j.ecoenv.2018.07.125] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 07/24/2018] [Accepted: 07/25/2018] [Indexed: 06/08/2023]
Abstract
Soil acts as a repository for many metals that human activity releases into the environment. Cadmium enters agricultural soils primarily from application of phosphate fertilizers and sewage sludge. Among soil bacteria, rhizobia have a great agronomic and environmental significance and are major contributors to a sustainable maintenance of soil fertility. However, the services that this group of microorganisms provides are affected by environmental constraints, such as Cd contamination. Bioactive compounds also influence soil microorganisms. Farnesol is a phytocompound with recognized bioactivity, inducing both beneficial and harmful effects. In this study, Rhizobium sp. strain E20-8 was exposed to sole or combined exposure to Cd and farnesol. Results showed that farnesol (25 and 200 µM) did not affect rhizobia; exposure to Cd (µM) inhibited rhizobia growth and induced several biomarkers of oxidative stress; exposure to the combination of farnesol and Cd reduced oxidative damage, and the highest concentration of farnesol tested reduced Cd accumulation and allowed a significant growth recovery. Farnesol protective effects on rhizobia exposed to Cd is novel information which can be used in the development of microbe-based environmental engineering strategies for restoration of metal contaminated areas.
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Affiliation(s)
- Tiago Nunes
- Department of Biology, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Paulo Cardoso
- Department of Biology & CESAM, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Rosa Freitas
- Department of Biology & CESAM, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Etelvina Figueira
- Department of Biology & CESAM, University of Aveiro, 3810-193 Aveiro, Portugal.
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5
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Jackson-Hayes L, Atiq Z, Betton B, Freyaldenhoven WT, Myers L, Olsen E, Hill TW. Aspergillus nidulans protein kinase C forms a complex with the formin SepA that is involved in apical growth and septation. Fungal Genet Biol 2018; 122:21-30. [PMID: 30391723 DOI: 10.1016/j.fgb.2018.10.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 10/22/2018] [Accepted: 10/23/2018] [Indexed: 10/27/2022]
Abstract
The Aspergillus nidulans orthologue of Protein kinase C (PkcA) and the A. nidulans formin SepA participate in polarized growth. PkcA localizes to growing hyphal apices and septation sites, and amino acid sequences within PkcA that are required for PkcA to localize to these sites of cell wall synthesis have been identified. SepA is associated with the contractile actomyosin ring (CAR), and it localizes at hyphal tips in association with the Spitzenkörper (SPK) and as an apical dome. A mutation in the sepA gene (sepA1) renders A. nidulans aseptate at elevated temperature. Progress towards understanding the spatiotemporal relationship between PkcA and SepA during polarized growth is presented here. Fluorescent chimeras of PkcA and SepA strongly overlapped in some hyphal tips in a dome pattern, while other tips displayed SepA SPK and PkcA dome localization within the same tip. At septation sites PkcA and SepA consistently colocalized through late stages of CAR constriction. Bimolecular fluorescence complementation experimental results provide evidence that SepA and PkcA are both present in complexes at both hyphal tip domes and at cortical rings. A Gal4-based yeast two-hybrid analysis confirmed the physical interaction between SepA and PkcA, and indicted that the FH2 domain of SepA is involved in its physical interaction with PkcA. A functional interaction between PkcA and SepA was shown through complementation of the pkcA calC2 mutant's hypersensitivity to cell wall perturbing agents by overexpressed sepA and by the ability of the sepA1 mutation to block PkcA's ability to form cortical rings. Taken together these results suggest that a PkcA/SepA complex is involved in polarized growth. Through experiments using the actin disrupter latrunculin B, evidence is presented suggesting that actin plays a role in the PkcA/SepA complex.
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Affiliation(s)
- Loretta Jackson-Hayes
- Department of Chemistry, Rhodes College, 2000 N. Parkway, Memphis, TN 38112, USA; Biochemistry and Molecular Biology Program, Rhodes College, 2000 N. Parkway, Memphis, TN 38112, USA.
| | - Zainab Atiq
- Biochemistry and Molecular Biology Program, Rhodes College, 2000 N. Parkway, Memphis, TN 38112, USA
| | - Brianna Betton
- Biochemistry and Molecular Biology Program, Rhodes College, 2000 N. Parkway, Memphis, TN 38112, USA
| | - W Toler Freyaldenhoven
- Biochemistry and Molecular Biology Program, Rhodes College, 2000 N. Parkway, Memphis, TN 38112, USA
| | - Lance Myers
- Biochemistry and Molecular Biology Program, Rhodes College, 2000 N. Parkway, Memphis, TN 38112, USA
| | - Elisabet Olsen
- Department of Chemistry, Rhodes College, 2000 N. Parkway, Memphis, TN 38112, USA
| | - Terry W Hill
- Biochemistry and Molecular Biology Program, Rhodes College, 2000 N. Parkway, Memphis, TN 38112, USA; Department of Biology, Rhodes College, 2000 N. Parkway, Memphis, TN 38112, USA
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Leiter É, Csernoch L, Pócsi I. Programmed cell death in human pathogenic fungi - a possible therapeutic target. Expert Opin Ther Targets 2018; 22:1039-1048. [PMID: 30360667 DOI: 10.1080/14728222.2018.1541087] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
INTRODUCTION Diseases caused by pathogenic fungi are increasing because of antibiotic overuse, the rise of immunosuppressive therapies, and climate change. The limited variety of antimycotics and the rapid adaptation of pathogenic fungi to antifungal agents serve to exacerbate this issue. Unfortunately, about 1.6 million people are killed by fungal infections annually. Areas covered: The discovery of the small antimicrobial proteins produced by microorganisms, animals, humans, and plants will hopefully overcome challenges in the treatment of fungal infections. These small proteins are highly stable and any resistance to them rarely evolves; therefore, they are potentially good candidates for the treatment and prevention of infections caused by pathogenic fungi. Some of these proteins target the programmed cell death machinery of pathogenic fungi; this is potentially a novel approach in antimycotic therapies. In this review, we highlight the elements of apoptosis in human pathogenic fungi and related model organisms and discuss the possible therapeutic potential of the apoptosis-inducing, small, antifungal proteins. Expert opinion: Small antimicrobial proteins may establish a new class of antimycotics in the future. The rarity of resistance and their synergistic effects with other frequently used antifungal agents may help pave the way for their use in the clinic.
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Affiliation(s)
- Éva Leiter
- a Department of Biotechnology and Microbiology , University of Debrecen , Debrecen , Hungary
| | - László Csernoch
- b Department of Physiology , University of Debrecen , Debrecen , Hungary
| | - István Pócsi
- a Department of Biotechnology and Microbiology , University of Debrecen , Debrecen , Hungary
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7
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Gonçalves AP, Heller J, Daskalov A, Videira A, Glass NL. Regulated Forms of Cell Death in Fungi. Front Microbiol 2017; 8:1837. [PMID: 28983298 PMCID: PMC5613156 DOI: 10.3389/fmicb.2017.01837] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2017] [Accepted: 09/07/2017] [Indexed: 12/15/2022] Open
Abstract
Cell death occurs in all domains of life. While some cells die in an uncontrolled way due to exposure to external cues, other cells die in a regulated manner as part of a genetically encoded developmental program. Like other eukaryotic species, fungi undergo programmed cell death (PCD) in response to various triggers. For example, exposure to external stress conditions can activate PCD pathways in fungi. Calcium redistribution between the extracellular space, the cytoplasm and intracellular storage organelles appears to be pivotal for this kind of cell death. PCD is also part of the fungal life cycle, in which it occurs during sexual and asexual reproduction, aging, and as part of development associated with infection in phytopathogenic fungi. Additionally, a fungal non-self-recognition mechanism termed heterokaryon incompatibility (HI) also involves PCD. Some of the molecular players mediating PCD during HI show remarkable similarities to major constituents involved in innate immunity in metazoans and plants. In this review we discuss recent research on fungal PCD mechanisms in comparison to more characterized mechanisms in metazoans. We highlight the role of PCD in fungi in response to exogenic compounds, fungal development and non-self-recognition processes and discuss identified intracellular signaling pathways and molecules that regulate fungal PCD.
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Affiliation(s)
- A Pedro Gonçalves
- Plant and Microbial Biology Department, University of California, BerkeleyBerkeley, CA, United States
| | - Jens Heller
- Plant and Microbial Biology Department, University of California, BerkeleyBerkeley, CA, United States
| | - Asen Daskalov
- Plant and Microbial Biology Department, University of California, BerkeleyBerkeley, CA, United States
| | - Arnaldo Videira
- Instituto de Ciências Biomédicas de Abel Salazar, Universidade do PortoPorto, Portugal.,I3S - Instituto de Investigação e Inovação em SaúdePorto, Portugal
| | - N Louise Glass
- Plant and Microbial Biology Department, University of California, BerkeleyBerkeley, CA, United States
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8
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Wang X, Wang Y, Zhou Y, Wei X. Farnesol induces apoptosis-like cell death in the pathogenic fungusAspergillus flavus. Mycologia 2017; 106:881-8. [PMID: 24895430 DOI: 10.3852/13-292] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
| | | | - Yuguang Zhou
- China General Microbiological Culture Collection Center, Institute of Microbiology, Chinese Academy of Sciences, No 3 1st West Beichen Road, Chaoyang District, Beijing, 100101, China
| | - Xinli Wei
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, No 3 1st West Beichen Road, Chaoyang District, Beijing, 100101, China
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9
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Tian J, Wang Y, Lu Z, Sun C, Zhang M, Zhu A, Peng X. Perillaldehyde, a Promising Antifungal Agent Used in Food Preservation, Triggers Apoptosis through a Metacaspase-Dependent Pathway in Aspergillus flavus. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2016; 64:7404-7413. [PMID: 27622540 DOI: 10.1021/acs.jafc.6b03546] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
In the present study, we provide detailed insights into perillaldehyde (PAE)'s mechanisms of action on Aspergillus flavus and offer evidence in favor of the induction of an apoptosis-like phenotype. Specifically, PAE's antifungal mode of action was investigated through the detection of mitochondrial membrane potential (MtΔψ) and phosphatidylserine (PS) exposure, as well as intracellular Ca2+ level, reactive oxygen species accumulation, and metacaspase activation. This was done by way of fluorometry, measuring DNA fragmentation, and condensation by fluorescent microscopy. Furthermore, we searched for phenotypic changes characteristic of apoptosis by transmission electron microscopy and flow cytometry, determining the amount of cytochrome c released using Western blotting. Results indicated that cultivation of A. flavus in the presence of PAE caused depolarization of MtΔψ, rapid DNA condensation, large-scale DNA fragmentation, and an elevation of intracellular Ca2+ level. The percentage of early apoptotic cells with exposure of PS were 27.4% and 48.7%, respectively, after 9 h incubations with 0.25 and 0.5 μL/mL of PAE. The percentage of stained cells with activated intracellular metacaspases exposed to PAE at concentrations of 0.25 and 0.5 μL/mL compared with control subjects were increased by 28.4 ± 3.25% and 37.9 ± 4.24%, respectively. The above results has revealed that PAE induces fungal apoptosis through a caspase-dependent mitochondrial pathway. In all, our findings provide a novel mechanism for exploring a possible antifungal agent used in food preservation.
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Affiliation(s)
- Jun Tian
- College of Life Science, Jiangsu Normal University , Xuzhou 221116, Jiangsu Province, People's Republic of China
- Key Lab for New Drug Research of TCM and Shenzhen Branch, State R&D Centre for Viro-Biotech, Research Institute of Tsinghua University in Shenzhen , Shenzhen 518057, Guangdong, People's Republic of China
| | - Yanzhen Wang
- College of Life Science, Jiangsu Normal University , Xuzhou 221116, Jiangsu Province, People's Republic of China
| | - Zhaoqun Lu
- College of Life Science, Jiangsu Normal University , Xuzhou 221116, Jiangsu Province, People's Republic of China
| | - Chunhui Sun
- College of Life Science, Jiangsu Normal University , Xuzhou 221116, Jiangsu Province, People's Republic of China
| | - Man Zhang
- College of Life Science, Jiangsu Normal University , Xuzhou 221116, Jiangsu Province, People's Republic of China
| | - Aihua Zhu
- College of Life Science, Jiangsu Normal University , Xuzhou 221116, Jiangsu Province, People's Republic of China
| | - Xue Peng
- College of Life Science, Jiangsu Normal University , Xuzhou 221116, Jiangsu Province, People's Republic of China
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10
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Yoshimi A, Miyazawa K, Abe K. Cell wall structure and biogenesis in Aspergillus species. Biosci Biotechnol Biochem 2016; 80:1700-11. [DOI: 10.1080/09168451.2016.1177446] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Abstract
Aspergillus species are among the most important filamentous fungi from the viewpoints of industry, pathogenesis, and mycotoxin production. Fungal cells are exposed to a variety of environmental stimuli, including changes in osmolality, temperature, and pH, which create stresses that primarily act on fungal cell walls. In addition, fungal cell walls are the first interactions with host cells in either human or plants. Thus, understanding cell wall structure and the mechanism of their biogenesis is important for the industrial, medical, and agricultural fields. Here, we provide a systematic review of fungal cell wall structure and recent findings regarding the cell wall integrity signaling pathways in aspergilli. This accumulated knowledge will be useful for understanding and improving the use of industrial aspergilli fermentation processes as well as treatments for some fungal infections.
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Affiliation(s)
- Akira Yoshimi
- ABE-project, New Industry Creation Hatchery Center, Tohoku University, Sendai, Japan
| | - Ken Miyazawa
- Laboratory of Applied Microbiology, Department of Microbial Biotechnology, Graduate School of Agricultural Sciences, Tohoku University, Sendai, Japan
| | - Keietsu Abe
- ABE-project, New Industry Creation Hatchery Center, Tohoku University, Sendai, Japan
- Laboratory of Applied Microbiology, Department of Microbial Biotechnology, Graduate School of Agricultural Sciences, Tohoku University, Sendai, Japan
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11
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Rocha MC, de Godoy KF, de Castro PA, Hori JI, Bom VLP, Brown NA, da Cunha AF, Goldman GH, Malavazi I. The Aspergillus fumigatus pkcA G579R Mutant Is Defective in the Activation of the Cell Wall Integrity Pathway but Is Dispensable for Virulence in a Neutropenic Mouse Infection Model. PLoS One 2015; 10:e0135195. [PMID: 26295576 PMCID: PMC4546635 DOI: 10.1371/journal.pone.0135195] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 07/19/2015] [Indexed: 12/03/2022] Open
Abstract
Aspergillus fumigatus is an opportunistic human pathogen, which causes the life-threatening disease, invasive pulmonary aspergillosis. In fungi, cell wall homeostasis is controlled by the conserved Cell Wall Integrity (CWI) pathway. In A. fumigatus this signaling cascade is partially characterized, but the mechanisms by which it is activated are not fully elucidated. In this study we investigated the role of protein kinase C (PkcA) in this signaling cascade. Our results suggest that pkcA is an essential gene and is activated in response to cell wall stress. Subsequently, we constructed and analyzed a non-essential A. fumigatus pkcAG579R mutant, carrying a Gly579Arg substitution in the PkcA C1B regulatory domain. The pkcAG579R mutation has a reduced activation of the downstream Mitogen-Activated Protein Kinase, MpkA, resulting in the altered expression of genes encoding cell wall-related proteins, markers of endoplasmic reticulum stress and the unfolded protein response. Furthermore, PkcAG579R is involved in the formation of proper conidial architecture and protection to oxidative damage. The pkcAG579R mutant elicits increased production of TNF-α and phagocytosis but it has no impact on virulence in a murine model of invasive pulmonary aspergillosis. These results highlight the importance of PkcA to the CWI pathway but also indicated that additional regulatory circuits may be involved in the biosynthesis and/or reinforcement of the A. fumigatus cell wall during infection.
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Affiliation(s)
- Marina Campos Rocha
- Departamento de Genética e Evolução, Centro de Ciências Biológicas e da Saúde, Universidade Federal de São Carlos, São Carlos, São Paulo, Brazil
| | - Krissia Franco de Godoy
- Departamento de Genética e Evolução, Centro de Ciências Biológicas e da Saúde, Universidade Federal de São Carlos, São Carlos, São Paulo, Brazil
| | - Patrícia Alves de Castro
- Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Juliana Issa Hori
- Departamento de Farmacologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Vinícius Leite Pedro Bom
- Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Neil Andrew Brown
- Department of Plant Biology and Crop Science, Rothamsted Research, Harpenden, Herts, United Kingdom
| | - Anderson Ferreira da Cunha
- Departamento de Genética e Evolução, Centro de Ciências Biológicas e da Saúde, Universidade Federal de São Carlos, São Carlos, São Paulo, Brazil
| | - Gustavo Henrique Goldman
- Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol, Campinas, São Paulo, Brazil
| | - Iran Malavazi
- Departamento de Genética e Evolução, Centro de Ciências Biológicas e da Saúde, Universidade Federal de São Carlos, São Carlos, São Paulo, Brazil
- * E-mail:
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12
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Virágh M, Marton A, Vizler C, Tóth L, Vágvölgyi C, Marx F, Galgóczy L. Insight into the antifungal mechanism of Neosartorya fischeri antifungal protein. Protein Cell 2015; 6:518-28. [PMID: 25994413 PMCID: PMC4491047 DOI: 10.1007/s13238-015-0167-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 04/10/2015] [Indexed: 11/28/2022] Open
Abstract
Small, cysteine-rich, highly stable antifungal proteins secreted by filamentous Ascomycetes have great potential for the development of novel antifungal strategies. However, their practical application is still limited due to their not fully clarified mode of action. The aim of this work was to provide a deep insight into the antifungal mechanism of Neosartorya fischeri antifungal protein (NFAP), a novel representative of this protein group. Within a short exposure time to NFAP, reduced cellular metabolism, apoptosis induction, changes in the actin distribution and chitin deposition at the hyphal tip were observed in NFAP-sensitive Aspergillus nidulans. NFAP did show neither a direct membrane disrupting-effect nor uptake by endocytosis. Investigation of A. nidulans signalling mutants revealed that NFAP activates the cAMP/protein kinase A pathway via G-protein signalling which leads to apoptosis and inhibition of polar growth. In contrast, NFAP does not have any influence on the cell wall integrity pathway, but an unknown cell wall integrity pathway-independent mitogen activated protein kinase A-activated target is assumed to be involved in the cell death induction. Taken together, it was concluded that NFAP shows similarities, but also differences in its mode of antifungal action compared to two most investigated NFAP-related proteins from Aspergillus giganteus and Penicillium chrysogenum.
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Affiliation(s)
- Máté Virágh
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
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13
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McLuskey K, Mottram J. Comparative structural analysis of the caspase family with other clan CD cysteine peptidases. Biochem J 2015; 466:219-32. [PMID: 25697094 PMCID: PMC4357240 DOI: 10.1042/bj20141324] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Revised: 11/19/2014] [Accepted: 12/08/2014] [Indexed: 11/29/2022]
Abstract
Clan CD forms a structural group of cysteine peptidases, containing seven individual families and two subfamilies of structurally related enzymes. Historically, it is most notable for containing the mammalian caspases, on which the structures of the clan were founded. Interestingly, the caspase family is split into two subfamilies: the caspases, and a second subfamily containing both the paracaspases and the metacaspases. Structural data are now available for both the paracaspases and the metacaspases, allowing a comprehensive structural analysis of the entire caspase family. In addition, a relative plethora of structural data has recently become available for many of the other families in the clan, allowing both the structures and the structure-function relationships of clan CD to be fully explored. The present review compares the enzymes in the caspase subfamilies with each other, together with a comprehensive comparison of all the structural families in clan CD. This reveals a diverse group of structures with highly conserved structural elements that provide the peptidases with a variety of substrate specificities and activation mechanisms. It also reveals conserved structural elements involved in substrate binding, and potential autoinhibitory functions, throughout the clan, and confirms that the metacaspases are structurally diverse from the caspases (and paracaspases), suggesting that they should form a distinct family of clan CD peptidases.
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Key Words
- caspase
- clan cd
- crystallography
- metacaspase
- peptidase
- protein structure
- ap, activation peptide
- card, caspase recruitment domain
- chf, caspase/haemoglobinase fold
- cpd, cysteine peptidase domain
- csd, c-terminal subdomain
- dd, death domain
- ded, death effector domain
- insp6, myo-inositol hexakisphosphate
- lsam, legumain stabilization and activity modulation
- lsd1, lesion-simulating disease 1
- malt1, mucosa-associated lymphoid tissue translocation protein 1
- martx, multi-functional, autoprocessing repeat in toxin
- rmsd, root-mean-square deviation
- sse, secondary structural element
- xiap, x-linked inhibitor of apoptosis
- z-vrpr-fmk, benzoxycarbonyl-val-arg-pro-arg-fluoromethylketone
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Affiliation(s)
- Karen McLuskey
- *Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, UK
| | - Jeremy C. Mottram
- *Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, UK
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14
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Katayama T, Ohta A, Horiuchi H. Protein kinase C regulates the expression of cell wall-related genes in RlmA-dependent and independent manners in Aspergillus nidulans. Biosci Biotechnol Biochem 2015; 79:321-30. [DOI: 10.1080/09168451.2014.973365] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Abstract
A protein kinase C of Aspergillus nidulans, PkcA, is required for cell wall integrity (CWI) and is considered a major component of the regulating pathway. To investigate whether PkcA regulates the transcription of cell wall-related genes, we constructed strains expressing pkcA(R429A) that encodes an activated form of PkcA. The mRNA levels of most chitin synthase genes and an α-glucan synthase gene, agsB, were increased when pkcA(R429A) expression was induced. These mRNA increases were not observed or were only partially observed, in a deletion mutant of rlmA, an ortholog of RLM1 that encodes a transcription factor in the CWI pathway in Saccharomyces cerevisiae. In addition, in a pkcA temperature-sensitive mutant under heat stress, the mRNA levels of some chitin synthase genes and agsB did not increase. These results suggest that PkcA is involved in CWI maintenance through the transcriptional regulation of cell wall-related genes.
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Affiliation(s)
- Takuya Katayama
- Department of Biotechnology, The University of Tokyo, Tokyo, Japan
| | - Akinori Ohta
- Department of Biotechnology, The University of Tokyo, Tokyo, Japan
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15
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Brown NA, Dos Reis TF, Goinski AB, Savoldi M, Menino J, Almeida MT, Rodrigues F, Goldman GH. The Aspergillus nidulans signalling mucin MsbA regulates starvation responses, adhesion and affects cellulase secretion in response to environmental cues. Mol Microbiol 2014; 94:1103-1120. [PMID: 25294314 DOI: 10.1111/mmi.12820] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/04/2014] [Indexed: 01/27/2023]
Abstract
In the heterogeneous semi-solid environment naturally occupied by lignocellulolytic fungi the majority of nutrients are locked away as insoluble plant biomass. Hence, lignocellulolytic fungi must actively search for, and attach to, a desirable source of nutrients. During growth on lignocellulose a period of carbon deprivation provokes carbon catabolite derepression and scavenging hydrolase secretion. Subsequently, starvation and/or contact sensing was hypothesized to play a role in lignocellulose attachment and degradation. In Aspergillus nidulans the extracellular signalling mucin, MsbA, influences growth under nutrient-poor conditions including lignocellulose. Cellulase secretion and activity was affected by MsbA via a mechanism that was independent of cellulase transcription. MsbA modulated both the cell wall integrity and filamentous growth MAPK pathways influencing adhesion, biofilm formation and secretion. The constitutive activation of MsbA subsequently enhanced cellulase activity by increasing the secretion of the cellobiohydrolase, CbhA, while improved substrate attachment and may contribute to an enhanced starvation response. Starvation and/or contact sensing therefore represents a new dimension to the already multifaceted regulation of cellulase activity.
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Affiliation(s)
- Neil Andrew Brown
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
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16
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Colabardini AC, Ries LNA, Brown NA, Savoldi M, Dinamarco TM, von Zeska MR, Goldman MHS, Goldman GH. Protein kinase C overexpression suppresses calcineurin-associated defects in Aspergillus nidulans and is involved in mitochondrial function. PLoS One 2014; 9:e104792. [PMID: 25153325 PMCID: PMC4143261 DOI: 10.1371/journal.pone.0104792] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2014] [Accepted: 07/11/2014] [Indexed: 12/22/2022] Open
Abstract
In filamentous fungi, intracellular signaling pathways which are mediated by changing calcium levels and/or by activated protein kinase C (Pkc), control fungal adaptation to external stimuli. A rise in intracellular Ca2+ levels activates calcineurin subunit A (CnaA), which regulates cellular calcium homeostasis among other processes. Pkc is primarily involved in maintaining cell wall integrity (CWI) in response to different environmental stresses. Cross-talk between the Ca2+ and Pkc-mediated pathways has mainly been described in Saccharomyces cerevisiae and in a few other filamentous fungi. The presented study describes a genetic interaction between CnaA and PkcA in the filamentous fungus Aspergillus nidulans. Overexpression of pkcA partially rescues the phenotypes caused by a cnaA deletion. Furthermore, CnaA appears to affect the regulation of a mitogen-activated kinase, MpkA, involved in the CWI pathway. Reversely, PkcA is involved in controlling intracellular calcium homeostasis, as was confirmed by microarray analysis. Furthermore, overexpression of pkcA in a cnaA deletion background restores mitochondrial number and function. In conclusion, PkcA and CnaA-mediated signaling appear to share common targets, one of which appears to be MpkA of the CWI pathway. Both pathways also regulate components involved in mitochondrial biogenesis and function. This study describes targets for PkcA and CnaA-signaling pathways in an A. nidulans and identifies a novel interaction of both pathways in the regulation of cellular respiration.
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Affiliation(s)
- Ana Cristina Colabardini
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | | | - Neil Andrew Brown
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - Marcela Savoldi
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - Taísa Magnani Dinamarco
- Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - Marcia Regina von Zeska
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - Maria Helena S. Goldman
- Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - Gustavo Henrique Goldman
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol – CTBE, Campinas, São Paulo, Brazil
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
- * E-mail:
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17
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Jiang H, Liu F, Zhang S, Lu L. Putative PmrA and PmcA are important for normal growth, morphogenesis and cell wall integrity, but not for viability in Aspergillus nidulans. MICROBIOLOGY-SGM 2014; 160:2387-2395. [PMID: 25118249 DOI: 10.1099/mic.0.080119-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
P-type Ca(2+)-transporting ATPases are Ca(2+) pumps, extruding cytosolic Ca(2+) to the extracellular environment or the intracellular Ca(2+) store lumens. In budding yeast, Pmr1 (plasma membrane ATPase related), and Pmc1 (plasma membrane calcium-ATPase) cannot be deleted simultaneously for it to survive in standard medium. Here, we deleted two putative Ca(2+) pumps, designated AnPmrA and AnPmcA, from Aspergillus nidulans, and obtained the mutants ΔanpmrA and ΔanpmcA, respectively. Then, using ΔanpmrA as the starting strain, the promoter of its anpmcA was replaced with the alcA promoter to secure the mutant ΔanpmrAalcApmcA or its anpmcA was deleted completely to produce the mutant ΔanpmrAΔpmcA. Different from the case in Saccharomyces cerevisiae, double deletion of anpmrA and anpmcA was not lethal in A. nidulans. In addition, deletion of anpmrA and/or anpmcA had produced growth defects, although overexpression of AnPmc1 in ΔanpmrAalcApmcA could not restore the growth defects that resulted from the loss of AnPmrA. Moreover, we found AnPmrA was indispensable for maintenance of normal morphogenesis, especially in low-Ca(2+)/Mn(2+) environments. Thus, our findings suggest AnPmrA and AnPmcA might play important roles in growth, morphogenesis and cell wall integrity in A. nidulans in a different way from that in yeasts.
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Affiliation(s)
- Hechun Jiang
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology; College of Life Sciences, Nanjing Normal University, Nanjing 210023, PR China
| | - Feifei Liu
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology; College of Life Sciences, Nanjing Normal University, Nanjing 210023, PR China
| | - Shizhu Zhang
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology; College of Life Sciences, Nanjing Normal University, Nanjing 210023, PR China
| | - Ling Lu
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology; College of Life Sciences, Nanjing Normal University, Nanjing 210023, PR China
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18
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Malavazi I, Goldman GH, Brown NA. The importance of connections between the cell wall integrity pathway and the unfolded protein response in filamentous fungi. Brief Funct Genomics 2014; 13:456-70. [PMID: 25060881 DOI: 10.1093/bfgp/elu027] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In the external environment, or within a host organism, filamentous fungi experience sudden changes in nutrient availability, osmolality, pH, temperature and the exposure to toxic compounds. The fungal cell wall represents the first line of defense, while also performing essential roles in morphology, development and virulence. A polarized secretion system is paramount for cell wall biosynthesis, filamentous growth, nutrient acquisition and interactions with the environment. The unique ability of filamentous fungi to secrete has resulted in their industrial adoption as fungal cell factories. Protein maturation and secretion commences in the endoplasmic reticulum (ER). The unfolded protein response (UPR) maintains ER functionality during exposure to secretion and cell wall stress. UPR, therefore, influences secretion and cell wall homeostasis, which in turn impacts upon numerous fungal traits important to pathogenesis and biotechnology. Subsequently, this review describes the relevance of the cell wall and UPR systems to filamentous fungal pathogens or industrial microbes and then highlights interconnections between the two systems. Ultimately, the possible biotechnological applications of an enhanced understanding of such regulatory systems in combating fungal disease, or the removal of natural bottlenecks in protein secretion in an industrial setting, are discussed.
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19
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Futagami T, Seto K, Kajiwara Y, Takashita H, Omori T, Takegawa K, Goto M. The putative stress sensor protein MtlA is required for conidia formation, cell wall stress tolerance, and cell wall integrity in Aspergillus nidulans. Biosci Biotechnol Biochem 2014; 78:326-35. [DOI: 10.1080/09168451.2014.878218] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Abstract
The Mid2-like protein MtlA is a putative sensor of the cell wall integrity (CWI) signaling pathway in Aspergillus nidulans. An MtlA-EGFP fusion protein was localized at the cell surface and septa. The mtlA disruptant (∆mtlA) showed radial colony growth similar to the wild-type (wt) strain, but showed reduced conidia formation. The ∆mtlA mutant showed growth deficiency in the presence of inhibitors of cell wall synthesis. Moreover, mtlA disruption resulted in a reduction in the glucan and chitin content in the cell wall. These results suggest that MtlA plays a significant role in asexual sporulation, cell wall stress tolerance, and the maintenance of CWI in A. nidulans, but transcriptional upregulation of α-1,3-glucan synthase gene agsB induced by micafungin was observed in the ∆mtlA strain as well as the wt strain. Thus, MtlA is not essential for activation of the downstream CWI signaling pathway components identified in previous studies of Saccharomyces cerevisiae.
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Affiliation(s)
- Taiki Futagami
- Department of Bioscience and Biotechnology, Faculty of Agriculture, Kyushu University, Fukuoka, Japan
| | - Kazufumi Seto
- Department of Bioscience and Biotechnology, Faculty of Agriculture, Kyushu University, Fukuoka, Japan
| | - Yasuhiro Kajiwara
- Research & Development Laboratory, Sanwa Shurui Co., Ltd., Usa, Japan
| | | | - Toshiro Omori
- Research & Development Laboratory, Sanwa Shurui Co., Ltd., Usa, Japan
| | - Kaoru Takegawa
- Department of Bioscience and Biotechnology, Faculty of Agriculture, Kyushu University, Fukuoka, Japan
| | - Masatoshi Goto
- Department of Bioscience and Biotechnology, Faculty of Agriculture, Kyushu University, Fukuoka, Japan
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20
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Dick SA, Megeney LA. Cell death proteins: an evolutionary role in cellular adaptation before the advent of apoptosis. Bioessays 2013; 35:974-83. [PMID: 23943356 DOI: 10.1002/bies.201300052] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Programmed cell death (PCD) or apoptosis is a broadly conserved phenomenon in metazoans, whereby activation of canonical signal pathways induces an ordered dismantling and death of a cell. Paradoxically, the constituent proteins and pathways of PCD (most notably the metacaspase/caspase protease mediated signal pathways) have been demonstrated to retain non-death functions across all phyla including yeast, nematodes, drosophila, and mammals. The ancient conservation of both death and non-death functions of PCD proteins raises an interesting evolutionary conundrum: was the primordial intent of these factors to induce cell death or to regulate other cellular adaptations? Here, we propose the hypothesis that apoptotic behavior of PCD proteins evolved or were co-opted from core non-death functions.
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Affiliation(s)
- Sarah A Dick
- Sprott Center for Stem Cell Research, Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada; Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
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21
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Katayama T, Uchida H, Ohta A, Horiuchi H. Involvement of protein kinase C in the suppression of apoptosis and in polarity establishment in Aspergillus nidulans under conditions of heat stress. PLoS One 2012; 7:e50503. [PMID: 23209763 PMCID: PMC3509046 DOI: 10.1371/journal.pone.0050503] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2012] [Accepted: 10/25/2012] [Indexed: 11/18/2022] Open
Abstract
The pkcA gene, which encodes a protein kinase C (PKC) in the filamentous fungus Aspergillus nidulans, is essential for its viability. However, little is known about its functions. To address this issue, we constructed and characterized temperature-sensitive mutants of pkcA. The conidia of these mutants swelled slightly and exhibited apoptotic phenotypes at 42°C. The apoptotic phenotypes were suppressed by an osmotic stabilizer. Under these conditions, the conidia swelled extensively and did not form germ tubes. Moreover, polarized distribution of F-actin was not observed. We then utilized deletion mutants of bckA, an ortholog of Saccharomyces cerevisiae bck1 that encodes a mitogen-activated protein (MAP) kinase kinase kinase and functions downstream of PKC in the cell wall integrity pathway. These mutants exhibited apoptotic phenotypes at 42°C, but they did not show defects in polarity establishment under osmotically stabilized conditions. These results suggest that PkcA plays multiple roles during germination under conditions of heat stress. The first of these roles is the suppression of apoptosis induction, while the other involves polarity establishment. The former depends on the MAP kinase cascade, whereas the latter does not. In addition, repolarization, which was observed after depolarization in the wild-type strain and the bckA deletion mutant under conditions of heat stress, was not observed in the pkcA-ts mutant. This suggests that PkcA also plays role in polarity establishment during hyphal growth independent of the MAP kinase cascade under these conditions.
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Affiliation(s)
- Takuya Katayama
- Department of Biotechnology, The University of Tokyo, Tokyo, Japan
| | - Hirotaka Uchida
- Department of Biotechnology, The University of Tokyo, Tokyo, Japan
| | - Akinori Ohta
- Department of Biotechnology, The University of Tokyo, Tokyo, Japan
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22
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Szilágyi M, Miskei M, Karányi Z, Lenkey B, Pócsi I, Emri T. Transcriptome changes initiated by carbon starvation in Aspergillus nidulans. MICROBIOLOGY-SGM 2012; 159:176-190. [PMID: 23154970 DOI: 10.1099/mic.0.062935-0] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Carbon starvation is a common stress for micro-organisms both in nature and in industry. The carbon starvation stress response (CSSR) involves the regulation of several important processes including programmed cell death and reproduction of fungi, secondary metabolite production and extracellular hydrolase formation. To gain insight into the physiological events of CSSR, DNA microarray analyses supplemented with real-time RT-PCR (rRT-PCR) experiments on 99 selected genes were performed. These data demonstrated that carbon starvation induced very complex changes in the transcriptome. Several genes contributing to protein synthesis were upregulated together with genes involved in the unfolded protein stress response. The balance between biosynthesis and degradation moved towards degradation in the case of cell wall, carbohydrate, lipid and nitrogen metabolism, which was accompanied by the production of several hydrolytic enzymes and the induction of macroautophagy. These processes provide the cultures with long-term survival by liberating nutrients through degradation of the cell constituents. The induced synthesis of secondary metabolites, antifungal enzymes and proteins as well as bacterial cell wall-degrading enzymes demonstrated that carbon-starving fungi should have marked effects on the micro-organisms in their surroundings. Due to the increased production of extracellular and vacuolar enzymes during carbon starvation, the importance of the endoplasmic reticulum increased considerably.
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Affiliation(s)
- Melinda Szilágyi
- Department of Microbial Biotechnology and Cell Biology, University of Debrecen, Egyetem tér 1, 4032 Debrecen, Hungary
| | - Márton Miskei
- Department of Microbial Biotechnology and Cell Biology, University of Debrecen, Egyetem tér 1, 4032 Debrecen, Hungary
| | - Zsolt Karányi
- Department of Medicine, University of Debrecen, Nagyerdei Körút 98, 4032 Debrecen, Hungary
| | - Béla Lenkey
- Department of Microbial Biotechnology and Cell Biology, University of Debrecen, Egyetem tér 1, 4032 Debrecen, Hungary
| | - István Pócsi
- Department of Microbial Biotechnology and Cell Biology, University of Debrecen, Egyetem tér 1, 4032 Debrecen, Hungary
| | - Tamás Emri
- Department of Microbial Biotechnology and Cell Biology, University of Debrecen, Egyetem tér 1, 4032 Debrecen, Hungary
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Shrestha A, Megeney LA. The non-death role of metacaspase proteases. Front Oncol 2012; 2:78. [PMID: 22837984 PMCID: PMC3402860 DOI: 10.3389/fonc.2012.00078] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2012] [Accepted: 07/05/2012] [Indexed: 11/24/2022] Open
Abstract
The activation of caspase proteases and the targeting of protein substrates act as key steps in the engagement and conduct of apoptosis/programmed cell death. However, the discovery of caspase involvement in diverse non-apoptotic cellular functions strongly suggests that these proteins may have evolved from a core behavior unrelated to the induction of cell death. The presence of similar proteases, termed metacaspases, in single cell organisms supports the contention that such proteins may have co-evolved or derived from a critical non-death function. Indeed, the benefit(s) for single cell life forms to retain proteins solely dedicated to self destruction would be countered by a strong selection pressure to curb or eliminate such processes. Examination of metacaspase biology provides evidence that these ancient protease forerunners of the caspase family also retain versatility in function, i.e., death and non-death cell functions. Here, we provide a critical review that highlights the non-death roles of metacaspases that have been described thus far, and the impact that these observations have for our understanding of the evolution and cellular utility of this protease family.
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Affiliation(s)
- Amit Shrestha
- Regenerative Medicine Program, Sprott Centre for Stem Cell Research, Ottawa Hospital Research Institute, The Ottawa Hospital, Ottawa, ON, Canada
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Proteome analysis of the farnesol-induced stress response in Aspergillus nidulans--The role of a putative dehydrin. J Proteomics 2012; 75:4038-49. [PMID: 22634043 DOI: 10.1016/j.jprot.2012.05.023] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2012] [Revised: 05/04/2012] [Accepted: 05/13/2012] [Indexed: 12/29/2022]
Abstract
The isoprenoid alcohol farnesol represents a quorum-sensing molecule in pathogenic yeasts, but was also shown to inhibit the growth of many filamentous fungi. In order to gain a deeper insight into the antifungal activity of farnesol, we performed 2D-differential gel electrophoretic analysis (2D-DIGE) of Aspergillus nidulans exposed to farnesol. We observed an increased abundance of antioxidative enzymes and proteins involved in protein folding and the ubiquitin-mediated protein degradation. A striking finding was the strong up-regulation of a dehydrin-like protein (DlpA). Expression analyses suggested the involvement of DlpA in the cellular response to oxidative, osmotic and cold stress. In line with these data, we demonstrated that dlpA expression was regulated by the MAP kinase SakA/HogA. The generation of both a dlpA Tet(on) antisense RNA-producing A. nidulans strain (dlpA-inv) and a ΔdlpA deletion mutant indicated a role of DlpA in conidiation and stress resistance of dormant conidia against heat and ROS. Furthermore, the production of the secondary metabolite sterigmatocystin was absent in both strains dlpA-inv and ΔdlpA. Our results demonstrate the complexity of the farnesol-mediated stress response in A. nidulans and describe a farnesol-inducible dehydrin-like protein that contributes to the high tolerance of resting conidia against oxidative and heat stress.
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Abstract
Quorum sensing (QS) is a mechanism of microbial communication dependent on cell density that can regulate several behaviors in bacteria such as secretion of virulence factors, biofilm formation, competence and bioluminescence. The existence of fungal QS systems was revealed ten years ago after the discovery that farnesol controls filamentation in the pathogenic polymorphic fungus Candida albicans. In the past decade, farnesol has been shown to play multiple roles in C. albicans physiology as a signaling molecule and inducing detrimental effects on host cells and other microbes. In addition to farnesol, the aromatic alcohol tyrosol was also found to be a C. albicans QS molecule (QSM) controlling growth, morphogenesis and biofilm formation. In Saccharomyces cerevisiae, two other aromatic alcohols, phenylethanol and tryptophol were found to be QSMs regulating morphogenesis during nitrogen starvation conditions. Additionally, population density-dependent behaviors that resemble QS have been described in several other fungal species. Although fungal QS research is still in its infancy, its discovery has changed our views about the fungal kingdom and could eventually lead to the development of new antifungal therapeutics.
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Affiliation(s)
- Patrícia Albuquerque
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York, USA.
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26
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Abstract
We
will discuss fungal communication in the context
of fundamental biological functions including
mating, growth, morphogenesis, and the regulation
of fungal virulence determinants. We will
address intraspecies but also interkingdom
signaling by systematically discussing the
sender of the message, the molecular message, and
receiver. Analyzing communication shows the
close coevolution of fungi with organisms
present in their environment giving insights
into multispecies communication. A better
understanding of the molecular mechanisms
underlying microbial communication will promote
our understanding of the “fungal
communicome.”
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27
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Farnesol-induced cell death in the filamentous fungus Aspergillus nidulans. Biochem Soc Trans 2011; 39:1544-8. [DOI: 10.1042/bst0391544] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
FOH (farnesol), a non-sterol isoprenoid produced by dephosphorylation of farnesyl pyrophosphate, has been shown to inhibit proliferation and induce apoptosis. We have been using Aspergillus nidulans and FOH as a model system and cell death stimulus, respectively, aiming to understand by which means filamentous fungi are driven towards cell death. Here, we review some of our findings about FOH-induced cell death in A. nidulans.
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Abstract
Metacaspases are cysteine-dependent proteases found in protozoa, fungi and plants and are distantly related to metazoan caspases. Although metacaspases share structural properties with those of caspases, they lack Asp specificity and cleave their targets after Arg or Lys residues. Studies performed over the past 10 years have demonstrated that metacaspases are multifunctional proteases essential for normal physiology of non-metazoan organisms. This article provides a comprehensive overview of the metacaspase function and molecular regulation during programmed cell death, stress and cell proliferation, as well as an analysis of the first metacaspase-mediated proteolytic pathway. To prevent further misapplication of caspase-specific molecular probes for measuring and inhibiting metacaspase activity, we provide a list of probes suitable for metacaspases.
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29
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The Aspergillus nidulans nucA(EndoG) homologue is not involved in cell death. EUKARYOTIC CELL 2010; 10:276-83. [PMID: 21131437 DOI: 10.1128/ec.00224-10] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Upon apoptosis induction, translocation of mammalian mitochondrial endonuclease G (EndoG) to the nucleus coincides with large-scale DNA fragmentation. Here, we describe for the first time a homologue of EndoG in filamentous fungi by investigating if the Aspergillus nidulans homologue of the EndoG gene, named nucA(EndoG), is being activated during farnesol-induced cell death. Our results suggest that NucA is not involved in cell death, but it plays a role in the DNA-damaging response in A. nidulans.
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