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Liu L, Li L, Li F, Ma W, Guo W, Fang X. Role of Pmk1, Mpk1, or Hog1 in the mitogen-activated protein kinase pathway of Aspergillus cristatus. Fungal Genet Biol 2024; 171:103874. [PMID: 38307402 DOI: 10.1016/j.fgb.2024.103874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 01/04/2024] [Accepted: 01/22/2024] [Indexed: 02/04/2024]
Abstract
Aspergillus cristatus is a probiotic fungus known for its safety and abundant secondary metabolites, making it a promising candidate for various applications. However, limited progress has been made in researching A. cristatus due to challenges in genetic manipulation. The mitogen-activated protein kinase (MAPK) signaling pathway is involved in numerous physiological processes, but its specific role in A. cristatus remains unclear. In this study, we successfully developed an efficient polyethylene glycol (PEG)-mediated protoplast transformation method for A. cristatus, enabling us to investigate the function of Pmk1, Mpk1, and Hog1 in the MAPK signaling pathway. Our findings revealed that Pmk1, Mpk1, and Hog1 are crucial for sexual reproduction, melanin synthesis, and response to external stress in A. cristatus. Notably, the deletion of Pmk1, Mpk1, or Hog1 resulted in the loss of sexual reproduction capability in A. cristatus. Overall, this research on MAPK will contribute to the continued understanding of the reproductive strategy and melanin synthesis mechanism of A. cristatus.
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Affiliation(s)
- Lulu Liu
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 6266237, China
| | - Longyue Li
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 6266237, China
| | - Fengyi Li
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 6266237, China
| | - Wei Ma
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 6266237, China
| | - Wei Guo
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 6266237, China
| | - Xu Fang
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 6266237, China; Rongcheng Huihai Chuangda Biotechnology Co., Ltd., Weihai, Shandong 264309, China.
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2
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Bauer I, Sarikaya Bayram Ö, Bayram Ö. The use of immunoaffinity purification approaches coupled with LC-MS/MS offers a powerful strategy to identify protein complexes in filamentous fungi. Essays Biochem 2023; 67:877-892. [PMID: 37681641 DOI: 10.1042/ebc20220253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 08/23/2023] [Accepted: 08/25/2023] [Indexed: 09/09/2023]
Abstract
Fungi are a diverse group of organisms that can be both beneficial and harmful to mankind. They have advantages such as producing food processing enzymes and antibiotics, but they can also be pathogens and produce mycotoxins that contaminate food. Over the past two decades, there have been significant advancements in methods for studying fungal molecular biology. These advancements have led to important discoveries in fungal development, physiology, pathogenicity, biotechnology, and natural product research. Protein complexes and protein-protein interactions (PPIs) play crucial roles in fungal biology. Various methods, including yeast two-hybrid (Y2H) and bimolecular fluorescence complementation (BiFC), are used to investigate PPIs. However, affinity-based PPI methods like co-immunoprecipitation (Co-IP) are highly preferred because they represent the natural conditions of PPIs. In recent years, the integration of liquid chromatography coupled with mass spectrometry (LC-MS/MS) has been used to analyse Co-IPs, leading to the discovery of important protein complexes in filamentous fungi. In this review, we discuss the tandem affinity purification (TAP) method and single affinity purification methods such as GFP, HA, FLAG, and MYC tag purifications. These techniques are used to identify PPIs and protein complexes in filamentous fungi. Additionally, we compare the efficiency, time requirements, and material usage of Sepharose™ and magnetic-based purification systems. Overall, the advancements in fungal molecular biology techniques have provided valuable insights into the complex interactions and functions of proteins in fungi. The methods discussed in this review offer powerful tools for studying fungal biology and will contribute to further discoveries in this field.
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Affiliation(s)
- Ingo Bauer
- Institute of Molecular Biology, Biocenter, Medical University of Innsbruck, Innsbruck, Austria
| | | | - Özgür Bayram
- Department of Biology, Maynooth University, Maynooth, Co. Kildare, Ireland
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3
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Yu W, Pei R, Zhou J, Zeng B, Tu Y, He B. Molecular regulation of fungal secondary metabolism. World J Microbiol Biotechnol 2023; 39:204. [PMID: 37209190 DOI: 10.1007/s11274-023-03649-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Accepted: 05/15/2023] [Indexed: 05/22/2023]
Abstract
Many bioactive secondary metabolites synthesized by fungi have important applications in many fields, such as agriculture, food, medical and others. The biosynthesis of secondary metabolites is a complex process involving a variety of enzymes and transcription factors, which are regulated at different levels. In this review, we describe our current understanding on molecular regulation of fungal secondary metabolite biosynthesis, such as environmental signal regulation, transcriptional regulation and epigenetic regulation. The effects of transcription factors on the secondary metabolites produced by fungi were mainly introduced. It was also discussed that new secondary metabolites could be found in fungi and the production of secondary metabolites could be improved. We also highlight the importance of understanding the molecular regulation mechanisms to activate silent secondary metabolites and uncover their physiological and ecological functions. By comprehensively understanding the regulatory mechanisms involved in secondary metabolite biosynthesis, we can develop strategies to improve the production of these compounds and maximize their potential benefits.
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Affiliation(s)
- Wenbin Yu
- Jiangxi Key Laboratory of Bioprocess Engineering, College of Life Sciences, Jiangxi Science & Technology Normal University, Nanchang, 330013, Jiangxi, China
| | - Rongqiang Pei
- Jiangxi Key Laboratory of Bioprocess Engineering, College of Life Sciences, Jiangxi Science & Technology Normal University, Nanchang, 330013, Jiangxi, China
| | - Jingyi Zhou
- Zhanjiang Preschool Education College, Zhanjiang, 524084, Guangdong, China
| | - Bin Zeng
- Jiangxi Key Laboratory of Bioprocess Engineering, College of Life Sciences, Jiangxi Science & Technology Normal University, Nanchang, 330013, Jiangxi, China
- College of Pharmacy, Shenzhen Technology University, Shenzhen, 518000, Guangdong, China
| | - Yayi Tu
- Jiangxi Key Laboratory of Bioprocess Engineering, College of Life Sciences, Jiangxi Science & Technology Normal University, Nanchang, 330013, Jiangxi, China.
| | - Bin He
- Jiangxi Key Laboratory of Bioprocess Engineering, College of Life Sciences, Jiangxi Science & Technology Normal University, Nanchang, 330013, Jiangxi, China.
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4
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Yang K, Tian J, Keller NP. Post-translational modifications drive secondary metabolite biosynthesis in Aspergillus: a review. Environ Microbiol 2022; 24:2857-2881. [PMID: 35645150 PMCID: PMC9545273 DOI: 10.1111/1462-2920.16034] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2022] [Revised: 04/23/2022] [Accepted: 04/26/2022] [Indexed: 12/26/2022]
Abstract
Post‐translational modifications (PTMs) are important for protein function and regulate multiple cellular processes and secondary metabolites (SMs) in fungi. Aspergillus species belong to a genus renown for an abundance of bioactive secondary metabolites, many important as toxins, pharmaceuticals and in industrial production. The genes required for secondary metabolites are typically co‐localized in biosynthetic gene clusters (BGCs), which often localize in heterochromatic regions of genome and are ‘turned off’ under laboratory condition. Efforts have been made to ‘turn on’ these BGCs by genetic manipulation of histone modifications, which could convert the heterochromatic structure to euchromatin. Additionally, non‐histone PTMs also play critical roles in the regulation of secondary metabolism. In this review, we collate the known roles of epigenetic and PTMs on Aspergillus SM production. We also summarize the proteomics approaches and bioinformatics tools for PTM identification and prediction and provide future perspectives on the emerging roles of PTM on regulation of SM biosynthesis in Aspergillus and other fungi.
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Affiliation(s)
- Kunlong Yang
- School of Life Science, Jiangsu Normal University, Xuzhou, 221116, Jiangsu Province, People's Republic of China.,Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, Wisconsin, 53705, USA
| | - Jun Tian
- School of Life Science, Jiangsu Normal University, Xuzhou, 221116, Jiangsu Province, People's Republic of China
| | - Nancy P Keller
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, Wisconsin, 53705, USA
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5
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Carrasco-Navarro U, Aguirre J. H 2O 2 Induces Major Phosphorylation Changes in Critical Regulators of Signal Transduction, Gene Expression, Metabolism and Developmental Networks in Aspergillus nidulans. J Fungi (Basel) 2021; 7:624. [PMID: 34436163 PMCID: PMC8399174 DOI: 10.3390/jof7080624] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 07/27/2021] [Accepted: 07/28/2021] [Indexed: 12/13/2022] Open
Abstract
Reactive oxygen species (ROS) regulate several aspects of cell physiology in filamentous fungi including the antioxidant response and development. However, little is known about the signaling pathways involved in these processes. Here, we report Aspergillus nidulans global phosphoproteome during mycelial growth and show that under these conditions, H2O2 induces major changes in protein phosphorylation. Among the 1964 phosphoproteins we identified, H2O2 induced the phosphorylation of 131 proteins at one or more sites as well as the dephosphorylation of a larger set of proteins. A detailed analysis of these phosphoproteins shows that H2O2 affected the phosphorylation of critical regulatory nodes of phosphoinositide, MAPK, and TOR signaling as well as the phosphorylation of multiple proteins involved in the regulation of gene expression, primary and secondary metabolism, and development. Our results provide a novel and extensive protein phosphorylation landscape in A. nidulans, indicating that H2O2 induces a shift in general metabolism from anabolic to catabolic, and the activation of multiple stress survival pathways. Our results expand the significance of H2O2 in eukaryotic cell signaling.
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Affiliation(s)
| | - Jesús Aguirre
- Departamento de Biología Celular y del Desarrollo, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Apartado Postal 70-242, Ciudad de México 04510, Mexico;
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6
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Xiong D, Yu L, Shan H, Tian C. CcPmk1 is a regulator of pathogenicity in Cytospora chrysosperma and can be used as a potential target for disease control. MOLECULAR PLANT PATHOLOGY 2021; 22:710-726. [PMID: 33835616 PMCID: PMC8126189 DOI: 10.1111/mpp.13059] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 03/07/2021] [Accepted: 03/09/2021] [Indexed: 05/13/2023]
Abstract
Fus3/Kss1, also known as Pmk1 in several pathogenic fungi, is a component of the mitogen-activated protein kinase (MAPK) signalling pathway that functions as a regulator in fungal development, stress response, mating, and pathogenicity. Cytospora chrysosperma, a notorious woody plant-pathogenic fungus, causes canker disease in many species, and its Pmk1 homolog, CcPmk1, is required for fungal development and pathogenicity. However, the global regulation network of CcPmk1 is still unclear. In this study, we compared transcriptional analysis between a CcPmk1 deletion mutant and the wild type during the simulated infection process. A subset of transcription factor genes and putative effector genes were significantly down-regulated in the CcPmk1 deletion mutant, which might be important for fungal pathogenicity. Additionally, many tandem genes were found to be regulated by CcPmk1. Eleven out of 68 core secondary metabolism biosynthesis genes and several gene clusters were significantly down-regulated in the CcPmk1 deletion mutant. GO annotation of down-regulated genes showed that the ribosome biosynthesis-related processes were over-represented in the CcPmk1 deletion mutant. Comparison of the CcPmk1-regulated genes with the Pmk1-regulated genes from Magnaporthe oryzae revealed only a few overlapping regulated genes in both CcPmk1 and Pmk1, while the enrichment GO terms in the ribosome biosynthesis-related processes were also found. Subsequently, we calculated that in vitro feeding artificial small interference RNAs of CcPmk1 could silence the target gene, resulting in inhibited fungal growth. Furthermore, silencing of BcPmk1 in Botrytis cinerea with conserved CcPmk1 and BcPmk1 fragments could significantly compromise fungal virulence using the virus-induced gene silencing system in Nicotiana benthamiana. These results suggest that CcPmk1 functions as a regulator of pathogenicity and can potentially be designed as a target for broad-spectrum disease control, but unintended effects on nonpathogenic fungi need to be avoided.
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Affiliation(s)
- Dianguang Xiong
- The Key Laboratory for Silviculture and Conservation of Ministry of EducationCollege of ForestryBeijing Forestry UniversityBeijingChina
- Beijing Key Laboratory for Forest Pest ControlBeijing Forestry UniversityBeijingChina
| | - Lu Yu
- The Key Laboratory for Silviculture and Conservation of Ministry of EducationCollege of ForestryBeijing Forestry UniversityBeijingChina
| | - Huimin Shan
- The Key Laboratory for Silviculture and Conservation of Ministry of EducationCollege of ForestryBeijing Forestry UniversityBeijingChina
| | - Chengming Tian
- The Key Laboratory for Silviculture and Conservation of Ministry of EducationCollege of ForestryBeijing Forestry UniversityBeijingChina
- Beijing Key Laboratory for Forest Pest ControlBeijing Forestry UniversityBeijingChina
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7
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Starke J, Harting R, Maurus I, Leonard M, Bremenkamp R, Heimel K, Kronstad JW, Braus GH. Unfolded Protein Response and Scaffold Independent Pheromone MAP Kinase Signaling Control Verticillium dahliae Growth, Development, and Plant Pathogenesis. J Fungi (Basel) 2021; 7:jof7040305. [PMID: 33921172 PMCID: PMC8071499 DOI: 10.3390/jof7040305] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 04/12/2021] [Accepted: 04/12/2021] [Indexed: 12/13/2022] Open
Abstract
Differentiation, growth, and virulence of the vascular plant pathogen Verticillium dahliae depend on a network of interconnected cellular signaling cascades. The transcription factor Hac1 of the endoplasmic reticulum-associated unfolded protein response (UPR) is required for initial root colonization, fungal growth, and vascular propagation by conidiation. Hac1 is essential for the formation of microsclerotia as long-time survival resting structures in the field. Single endoplasmic reticulum-associated enzymes for linoleic acid production as precursors for oxylipin signal molecules support fungal growth but not pathogenicity. Microsclerotia development, growth, and virulence further require the pheromone response mitogen-activated protein kinase (MAPK) pathway, but without the Ham5 scaffold function. The MAPK phosphatase Rok1 limits resting structure development of V.dahliae, but promotes growth, conidiation, and virulence. The interplay between UPR and MAPK signaling cascades includes several potential targets for fungal growth control for supporting disease management of the vascular pathogen V.dahliae.
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Affiliation(s)
- Jessica Starke
- Department of Molecular Microbiology and Genetics, Institute of Microbiology and Genetics and Göttingen Center for Molecular Biosciences (GZMB), University of Göttingen, 37077 Göttingen, Germany; (J.S.); (R.H.); (I.M.); (M.L.); (R.B.); (K.H.)
| | - Rebekka Harting
- Department of Molecular Microbiology and Genetics, Institute of Microbiology and Genetics and Göttingen Center for Molecular Biosciences (GZMB), University of Göttingen, 37077 Göttingen, Germany; (J.S.); (R.H.); (I.M.); (M.L.); (R.B.); (K.H.)
| | - Isabel Maurus
- Department of Molecular Microbiology and Genetics, Institute of Microbiology and Genetics and Göttingen Center for Molecular Biosciences (GZMB), University of Göttingen, 37077 Göttingen, Germany; (J.S.); (R.H.); (I.M.); (M.L.); (R.B.); (K.H.)
| | - Miriam Leonard
- Department of Molecular Microbiology and Genetics, Institute of Microbiology and Genetics and Göttingen Center for Molecular Biosciences (GZMB), University of Göttingen, 37077 Göttingen, Germany; (J.S.); (R.H.); (I.M.); (M.L.); (R.B.); (K.H.)
| | - Rica Bremenkamp
- Department of Molecular Microbiology and Genetics, Institute of Microbiology and Genetics and Göttingen Center for Molecular Biosciences (GZMB), University of Göttingen, 37077 Göttingen, Germany; (J.S.); (R.H.); (I.M.); (M.L.); (R.B.); (K.H.)
| | - Kai Heimel
- Department of Molecular Microbiology and Genetics, Institute of Microbiology and Genetics and Göttingen Center for Molecular Biosciences (GZMB), University of Göttingen, 37077 Göttingen, Germany; (J.S.); (R.H.); (I.M.); (M.L.); (R.B.); (K.H.)
| | - James W. Kronstad
- Michael Smith Laboratories, Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada;
| | - Gerhard H. Braus
- Department of Molecular Microbiology and Genetics, Institute of Microbiology and Genetics and Göttingen Center for Molecular Biosciences (GZMB), University of Göttingen, 37077 Göttingen, Germany; (J.S.); (R.H.); (I.M.); (M.L.); (R.B.); (K.H.)
- Correspondence: ; Tel.: +49-(0)551-39-33771
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8
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Jun SC, Kim JH, Han KH. The Conserved MAP Kinase MpkB Regulates Development and Sporulation without Affecting Aflatoxin Biosynthesis in Aspergillus flavus. J Fungi (Basel) 2020; 6:jof6040289. [PMID: 33207581 PMCID: PMC7711526 DOI: 10.3390/jof6040289] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 11/12/2020] [Accepted: 11/13/2020] [Indexed: 12/20/2022] Open
Abstract
In eukaryotes, the MAP kinase signaling pathway plays pivotal roles in regulating the expression of genes required for growth, development, and stress response. Here, we deleted the mpkB gene (AFLA_034170), an ortholog of the Saccharomyces cerevisiae FUS3 gene, to characterize its function in Aspergillus flavus, a cosmopolitan, pathogenic, and aflatoxin-producing fungus. Previous studies revealed that MpkB positively regulates sexual and asexual differentiation in Aspergillus nidulans. In A. flavus, mpkB deletion resulted in an approximately 60% reduction in conidia production compared to the wild type without mycelial growth defects. Moreover, the mutant produced immature and abnormal conidiophores exhibiting vesicular dome-immaturity in the conidiophore head, decreased phialide numbers, and very short stalks. Interestingly, the ΔmpkB mutant could not produce sclerotia but produced aflatoxin B1 normally. Taken together, these results suggest that the A. flavus MpkB MAP kinase positively regulates conidiation and sclerotia formation but is not involved in the production of secondary metabolites such as aflatoxin B1.
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Affiliation(s)
| | - Jong-Hwa Kim
- Correspondence: (J.-H.K.); (K.-H.H.); Tel.: +82-63-290-1439 (J.-H.K.); +82-63-290-1427 (K.-H.H.)
| | - Kap-Hoon Han
- Correspondence: (J.-H.K.); (K.-H.H.); Tel.: +82-63-290-1439 (J.-H.K.); +82-63-290-1427 (K.-H.H.)
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9
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Frawley D, Bayram Ö. The pheromone response module, a mitogen-activated protein kinase pathway implicated in the regulation of fungal development, secondary metabolism and pathogenicity. Fungal Genet Biol 2020; 144:103469. [PMID: 32950720 DOI: 10.1016/j.fgb.2020.103469] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 08/05/2020] [Accepted: 08/10/2020] [Indexed: 12/15/2022]
Abstract
Mitogen-activated protein kinase (MAPK) pathways are highly conserved from yeast to human and are required for the regulation of a multitude of biological processes in eukaryotes. A pentameric MAPK pathway known as the Fus3 pheromone module was initially characterised in Saccharomyces cerevisiae and was shown to regulate cell fusion and sexual development. Individual orthologous pheromone module genes have since been found to be highly conserved in fungal genomes and have been shown to regulate a diverse array of cellular responses, such as cell growth, asexual and sexual development, secondary metabolite production and pathogenicity. However, information regarding the assembly and structure of orthologous pheromone modules, as well as the mechanisms of signalling and their biological significance is limited, specifically in filamentous fungal species. Recent studies have provided insight on the utilization of the pheromone module as a central signalling hub for the co-ordinated regulation of fungal development and secondary metabolite production. Various proteins of this pathway are also known to regulate reproduction and virulence in a range of plant pathogenic fungi. In this review, we discuss recent findings that help elucidate the structure of the pheromone module pathway in a myriad of fungal species and its implications in the control of fungal growth, development, secondary metabolism and pathogenicity.
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Affiliation(s)
- Dean Frawley
- Biology Department, Callan Building, Maynooth University, Maynooth, Co. Kildare, Ireland.
| | - Özgür Bayram
- Biology Department, Callan Building, Maynooth University, Maynooth, Co. Kildare, Ireland.
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10
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Schmidt S, Märker R, Ramšak B, Beier-Rosberger AM, Teichert I, Kück U. Crosstalk Between Pheromone Signaling and NADPH Oxidase Complexes Coordinates Fungal Developmental Processes. Front Microbiol 2020; 11:1722. [PMID: 32849367 PMCID: PMC7401384 DOI: 10.3389/fmicb.2020.01722] [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: 05/25/2020] [Accepted: 06/30/2020] [Indexed: 12/13/2022] Open
Abstract
Sexual and asexual development in filamentous ascomycetes is controlled by components of conserved signaling pathways. Here, we investigated the development of mutant strains lacking genes for kinases MAK2, MEK2, and MIK2, as well as the scaffold protein HAM5 of the pheromone response (PR) pathway. All had a defect in fruiting body development and hyphal fusion. Another phenotype was a defect in melanin-dependent ascospore germination. However, this deficiency was observed only in kinase deletion mutants, but not in strains lacking HAM5. Notably, the same developmental phenotypes were previously described for nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 1 (NOX1) mutants, but the germination defect was only seen in NOX2 mutants. These data suggest a molecular link between the pheromone signaling pathway and both NOX complexes. Using data from yeast two-hybrid (Y2H) analysis, we found that the scaffolding protein HAM5 interacts with NOR1, the regulator of NOX1 and NOX2 complexes. This interaction was further confirmed using differently fluorescent-labeled proteins to demonstrate that NOR1 and HAM5 co-localize at cytoplasmic spots and tips of mature hyphae. This observation was supported by phenotypic characterization of single and double mutants. The oxidative stress response and the initiation of fruiting bodies were similar in Δham5Δnor1 and Δham5, but distinctly reduced in Δnor1, indicating that the double deletion leads to a partial suppression of the Δnor1 phenotype. We conclude that the PR and NOX1 complexes are connected by direct interaction between HAM5 and NOR1. In contrast, PR kinases are linked to the NOX2 complex without participation of HAM5.
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Affiliation(s)
| | | | | | | | | | - Ulrich Kück
- Allgemeine und Molekulare Botanik, Ruhr-Universität Bochum, Bochum, Germany
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11
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Frawley D, Stroe MC, Oakley BR, Heinekamp T, Straßburger M, Fleming AB, Brakhage AA, Bayram Ö. The Pheromone Module SteC-MkkB-MpkB-SteD-HamE Regulates Development, Stress Responses and Secondary Metabolism in Aspergillus fumigatus. Front Microbiol 2020; 11:811. [PMID: 32457716 PMCID: PMC7223695 DOI: 10.3389/fmicb.2020.00811] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 04/06/2020] [Indexed: 11/13/2022] Open
Abstract
In order for eukaryotes to efficiently detect and respond to environmental stimuli, a myriad of protein signaling pathways are utilized. An example of highly conserved signaling pathways in eukaryotes are the mitogen-activated protein kinase (MAPK) pathways. In fungi, MAPK pathways have been shown to regulate a diverse array of biological processes, such as asexual and sexual development, stress responses and the production of secondary metabolites (SMs). In the model fungus Aspergillus nidulans, a MAPK pathway known as the pheromone module is utilized to regulate both development and SM production. This signaling cascade consists of the three kinases SteC, MkkB, and MpkB, as well as the SteD adaptor protein and the HamE scaffold. In this study, homologs of each of these proteins have been identified in the opportunistic human pathogen A. fumigatus. By performing epitope tagging and mass spectrometry experiments, we have shown that these proteins form a pentameric complex, similar to what is observed in A. nidulans. This complex has been shown to assemble in the cytoplasm and MpkB enters the nucleus, where it would presumably interact with various transcription factors. Pheromone module mutant strains exhibit drastic reductions in asexual sporulation, vegetative growth rate and production of SMs, such as gliotoxin. Mutants also display increased sensitivity to cell wall and oxidative stress agents. Overall, these data provide evidence of the existence of a conserved MAP kinase signaling pathway in Aspergillus species and suggest that this pathway is critical for the regulation of fungal development and secondary metabolism.
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Affiliation(s)
- Dean Frawley
- Department of Biology, Fungal Genetics and Secondary Metabolism Laboratory, Maynooth University, Maynooth, Ireland
| | - Maria C Stroe
- Department of Molecular and Applied Microbiology, Hans Knöll Institute (HKI), Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany
| | - Berl R Oakley
- Department of Molecular Biosciences, University of Kansas, Lawrence, KS, United States
| | - Thorsten Heinekamp
- Department of Molecular and Applied Microbiology, Hans Knöll Institute (HKI), Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany
| | - Maria Straßburger
- Transfer Group Antiinfectives, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knöll Institute (HKI), Jena, Germany
| | - Alastair B Fleming
- Department of Microbiology, School of Genetics and Microbiology, Moyne Institute of Preventive Medicine, Trinity College Dublin, Dublin, Ireland
| | - Axel A Brakhage
- Department of Molecular and Applied Microbiology, Hans Knöll Institute (HKI), Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany.,Department of Microbiology and Molecular Biology, Institute of Microbiology, Friedrich Schiller University, Jena, Germany
| | - Özgür Bayram
- Department of Biology, Fungal Genetics and Secondary Metabolism Laboratory, Maynooth University, Maynooth, Ireland
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12
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Frawley D, Bayram Ö. Identification of SkpA-CulA-F-box E3 ligase complexes in pathogenic Aspergilli. Fungal Genet Biol 2020; 140:103396. [PMID: 32325169 DOI: 10.1016/j.fgb.2020.103396] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 04/16/2020] [Accepted: 04/17/2020] [Indexed: 11/29/2022]
Abstract
The ubiquitin proteasome system is critical for the regulation of protein turnover, which is implicated in the modulation of a wide array of biological processes in eukaryotes, ranging from cell senescence to virulence in plant and human hosts. Proteins to be marked for ubiquitination and subsequent degradation are bound by F-box proteins, which are interchangeable substrate-recognising receptors. These F-box proteins bind a wide range of substrates and associate with the adaptor protein Skp1 and the scaffold Cul1 to form Skp1-Cul1-F-box (SCF) complexes. SCF complex components are highly conserved in eukaryotes, ranging from yeast to humans. However, information regarding the composition of these complexes and the biological roles of F-box proteins is limited, specifically in filamentous fungal species like the genus Aspergillus. In this study, we have identified 51 and 55 fbx-encoding genes in the genomes of two pathogenic fungi, A. fumigatus and A. flavus, respectively. Immunoprecipitations of the HA-tagged SkpA adaptor protein revealed that 26 F-box proteins in A. fumigatus and 30 F-box proteins in A. flavus are involved in SCF complex formation during vegetative growth. These interactome data also revealed that a diverse array of SCF complex conformations exist in response to various exogenous stressors. Lastly, we have provided evidence that the F-box protein Fbx45 interacts with SkpA in both species in response to Amphotericin B. Orthologs of the fbx45 gene are highly conserved in Aspergillus species, but are not present within the genomes of organisms such as yeast, plants or humans. This suggests that Fbx45 could potentially be a novel F-box protein that is unique to specific filamentous fungi such as Aspergillus species.
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Affiliation(s)
- Dean Frawley
- Biology Department, Maynooth University, Maynooth, Co. Kildare, Ireland.
| | - Özgür Bayram
- Biology Department, Maynooth University, Maynooth, Co. Kildare, Ireland.
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13
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Frawley D, Greco C, Oakley B, Alhussain MM, Fleming AB, Keller NP, Bayram Ö. The tetrameric pheromone module SteC-MkkB-MpkB-SteD regulates asexual sporulation, sclerotia formation and aflatoxin production in Aspergillus flavus. Cell Microbiol 2020; 22:e13192. [PMID: 32068947 PMCID: PMC7202998 DOI: 10.1111/cmi.13192] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 01/07/2020] [Accepted: 01/26/2020] [Indexed: 11/29/2022]
Abstract
For eukaryotes like fungi to regulate biological responses to environmental stimuli, various signalling cascades are utilized, like the highly conserved mitogen‐activated protein kinase (MAPK) pathways. In the model fungus Aspergillus nidulans, a MAPK pathway known as the pheromone module regulates development and the production of secondary metabolites (SMs). This pathway consists five proteins, the three kinases SteC, MkkB and MpkB, the adaptor SteD and the scaffold HamE. In this study, homologs of these five pheromone module proteins have been identified in the plant and human pathogenic fungus Aspergillus flavus. We have shown that a tetrameric complex consisting of the three kinases and the SteD adaptor is assembled in this species. It was observed that this complex assembles in the cytoplasm and that MpkB translocates into the nucleus. Deletion of steC, mkkB, mpkB or steD results in abolishment of both asexual sporulation and sclerotia production. This complex is required for the positive regulation of aflatoxin production and negative regulation of various SMs, including leporin B and cyclopiazonic acid (CPA), likely via MpkB interactions in the nucleus. These data highlight the conservation of the pheromone module in Aspergillus species, signifying the importance of this pathway in regulating fungal development and secondary metabolism.
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Affiliation(s)
- Dean Frawley
- Department of Biology, Maynooth University, Maynooth, Co. Kildare, Ireland
| | - Claudio Greco
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Berl Oakley
- Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas, USA
| | - Mohamed M Alhussain
- Department of Microbiology, School of Genetics and Microbiology, Moyne Institute of Preventive Medicine, Trinity College Dublin, Dublin, Ireland
| | - Alastair B Fleming
- Department of Microbiology, School of Genetics and Microbiology, Moyne Institute of Preventive Medicine, Trinity College Dublin, Dublin, Ireland
| | - Nancy P Keller
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, Wisconsin, USA.,Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Özgür Bayram
- Department of Biology, Maynooth University, Maynooth, Co. Kildare, Ireland
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14
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Bayram ÖS, Dettmann A, Karahoda B, Moloney NM, Ormsby T, McGowan J, Cea-Sánchez S, Miralles-Durán A, Brancini GTP, Luque EM, Fitzpatrick DA, Cánovas D, Corrochano LM, Doyle S, Selker EU, Seiler S, Bayram Ö. Control of Development, Secondary Metabolism and Light-Dependent Carotenoid Biosynthesis by the Velvet Complex of Neurospora crassa. Genetics 2019; 212:691-710. [PMID: 31068340 PMCID: PMC6614901 DOI: 10.1534/genetics.119.302277] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 05/04/2019] [Indexed: 01/24/2023] Open
Abstract
Neurospora crassa is an established reference organism to investigate carotene biosynthesis and light regulation. However, there is little evidence of its capacity to produce secondary metabolites. Here, we report the role of the fungal-specific regulatory velvet complexes in development and secondary metabolism (SM) in N. crassa Three velvet proteins VE-1, VE-2, VOS-1, and a putative methyltransferase LAE-1 show light-independent nucleocytoplasmic localization. Two distinct velvet complexes, a heterotrimeric VE-1/VE-2/LAE-1 and a heterodimeric VE-2/VOS-1 are found in vivo The heterotrimer-complex, which positively regulates sexual development and represses asexual sporulation, suppresses siderophore coprogen production under iron starvation conditions. The VE-1/VE-2 heterodimer controls carotene production. VE-1 regulates the expression of >15% of the whole genome, comprising mainly regulatory and developmental features. We also studied intergenera functions of the velvet complex through complementation of Aspergillus nidulans veA, velB, laeA, vosA mutants with their N. crassa orthologs ve-1, ve-2, lae-1, and vos-1, respectively. Expression of VE-1 and VE-2 in A. nidulans successfully substitutes the developmental and SM functions of VeA and VelB by forming two functional chimeric velvet complexes in vivo, VelB/VE-1/LaeA and VE-2/VeA/LaeA, respectively. Reciprocally, expression of veA restores the phenotypes of the N. crassa ve-1 mutant. All N. crassa velvet proteins heterologously expressed in A. nidulans are localized to the nuclear fraction independent of light. These data highlight the conservation of the complex formation in N. crassa and A. nidulans However, they also underline the intergenera similarities and differences of velvet roles according to different life styles, niches and ontogenetic processes.
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Affiliation(s)
| | - Anne Dettmann
- Institute for Biology II, Molecular Plant Physiology, Albert-Ludwigs-University 79104 Freiburg, Germany
| | - Betim Karahoda
- Department of Biology, Maynooth University, Co. Kildare, W23 F2H6, Ireland
| | - Nicola M Moloney
- Department of Biology, Maynooth University, Co. Kildare, W23 F2H6, Ireland
| | - Tereza Ormsby
- Institute of Molecular Biology, University of Oregon, Eugene, 97403 Oregon
| | - Jamie McGowan
- Department of Biology, Maynooth University, Co. Kildare, W23 F2H6, Ireland
| | - Sara Cea-Sánchez
- Departmento de Genética, Facultad de Biologia, Universidad de Sevilla, 41012 Sevilla, Spain
| | | | - Guilherme T P Brancini
- Departmento de Genética, Facultad de Biologia, Universidad de Sevilla, 41012 Sevilla, Spain
| | - Eva M Luque
- Departmento de Genética, Facultad de Biologia, Universidad de Sevilla, 41012 Sevilla, Spain
| | | | - David Cánovas
- Departmento de Genética, Facultad de Biologia, Universidad de Sevilla, 41012 Sevilla, Spain
| | - Luis M Corrochano
- Departmento de Genética, Facultad de Biologia, Universidad de Sevilla, 41012 Sevilla, Spain
| | - Sean Doyle
- Department of Biology, Maynooth University, Co. Kildare, W23 F2H6, Ireland
| | - Eric U Selker
- Institute of Molecular Biology, University of Oregon, Eugene, 97403 Oregon
| | - Stephan Seiler
- Institute for Biology II, Molecular Plant Physiology, Albert-Ludwigs-University 79104 Freiburg, Germany
| | - Özgür Bayram
- Department of Biology, Maynooth University, Co. Kildare, W23 F2H6, Ireland
- Human Health Research Institute, Maynooth University, Co. Kildare, W23 F2H6, Ireland
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15
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Assembly of a heptameric STRIPAK complex is required for coordination of light-dependent multicellular fungal development with secondary metabolism in Aspergillus nidulans. PLoS Genet 2019; 15:e1008053. [PMID: 30883543 PMCID: PMC6438568 DOI: 10.1371/journal.pgen.1008053] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Revised: 03/28/2019] [Accepted: 02/28/2019] [Indexed: 12/19/2022] Open
Abstract
Eukaryotic striatin forms striatin-interacting phosphatase and kinase (STRIPAK) complexes that control many cellular processes including development, cellular transport, signal transduction, stem cell differentiation and cardiac functions. However, detailed knowledge of complex assembly and its roles in stress responses are currently poorly understood. Here, we discovered six striatin (StrA) interacting proteins (Sips), which form a heptameric complex in the filamentous fungus Aspergillus nidulans. The complex consists of the striatin scaffold StrA, the Mob3-type kinase coactivator SipA, the SIKE-like protein SipB, the STRIP1/2 homolog SipC, the SLMAP-related protein SipD and the catalytic and regulatory phosphatase 2A subunits SipE (PpgA), and SipF, respectively. Single and double deletions of the complex components result in loss of multicellular light-dependent fungal development, secondary metabolite production (e.g. mycotoxin Sterigmatocystin) and reduced stress responses. sipA (Mob3) deletion is epistatic to strA deletion by supressing all the defects caused by the lack of striatin. The STRIPAK complex, which is established during vegetative growth and maintained during the early hours of light and dark development, is mainly formed on the nuclear envelope in the presence of the scaffold StrA. The loss of the scaffold revealed three STRIPAK subcomplexes: (I) SipA only interacts with StrA, (II) SipB-SipD is found as a heterodimer, (III) SipC, SipE and SipF exist as a heterotrimeric complex. The STRIPAK complex is required for proper expression of the heterotrimeric VeA-VelB-LaeA complex which coordinates fungal development and secondary metabolism. Furthermore, the STRIPAK complex modulates two important MAPK pathways by promoting phosphorylation of MpkB and restricting nuclear shuttling of MpkC in the absence of stress conditions. SipB in A. nidulans is similar to human suppressor of IKK-ε(SIKE) protein which supresses antiviral responses in mammals, while velvet family proteins show strong similarity to mammalian proinflammatory NF-KB proteins. The presence of these proteins in A. nidulans further strengthens the hypothesis that mammals and fungi use similar proteins for their immune response and secondary metabolite production, respectively. The multisubunit STRIPAK complex has been studied from yeast to human and plays a range of roles from cell-cycle arrest, fruit body formation to neuronal functions. Molecular assembly of the STRIPAK complex and its roles in stress responses are not well-documented. Fungi, with an estimated 1.5 million members are friends and foes of mankind, acting as pathogens, natural product and enzyme producers. In filamentous fungus Aspergillus nidulans, we found a heptameric STRIPAK core complex made from three subcomplexes, which sits on the nuclear envelope and coordinates signal influx for light-dependent fungal development, secondary metabolism and stress responses. STRIPAK complex controls activities of two major Mitogen Activated Protein Kinase (MAPK) signaling pathways through either promoting their phosphorylation or limiting their nuclear localization under resting conditions. These findings establish a basis for how fungi govern signal influx by using multimeric scaffold protein complexes on the nuclear envelope to control different downstream pathways.
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