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Son YE, Yu JH, Park HS. Regulators of the Asexual Life Cycle of Aspergillus nidulans. Cells 2023; 12:1544. [PMID: 37296664 PMCID: PMC10253035 DOI: 10.3390/cells12111544] [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: 04/30/2023] [Revised: 06/01/2023] [Accepted: 06/02/2023] [Indexed: 06/12/2023] Open
Abstract
The genus Aspergillus, one of the most abundant airborne fungi, is classified into hundreds of species that affect humans, animals, and plants. Among these, Aspergillus nidulans, as a key model organism, has been extensively studied to understand the mechanisms governing growth and development, physiology, and gene regulation in fungi. A. nidulans primarily reproduces by forming millions of asexual spores known as conidia. The asexual life cycle of A. nidulans can be simply divided into growth and asexual development (conidiation). After a certain period of vegetative growth, some vegetative cells (hyphae) develop into specialized asexual structures called conidiophores. Each A. nidulans conidiophore is composed of a foot cell, stalk, vesicle, metulae, phialides, and 12,000 conidia. This vegetative-to-developmental transition requires the activity of various regulators including FLB proteins, BrlA, and AbaA. Asymmetric repetitive mitotic cell division of phialides results in the formation of immature conidia. Subsequent conidial maturation requires multiple regulators such as WetA, VosA, and VelB. Matured conidia maintain cellular integrity and long-term viability against various stresses and desiccation. Under appropriate conditions, the resting conidia germinate and form new colonies, and this process is governed by a myriad of regulators, such as CreA and SocA. To date, a plethora of regulators for each asexual developmental stage have been identified and investigated. This review summarizes our current understanding of the regulators of conidial formation, maturation, dormancy, and germination in A. nidulans.
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Affiliation(s)
- Ye-Eun Son
- Major in Food Biomaterials, School of Food Science and Biotechnology, Kyungpook National University, Daegu 41566, Republic of Korea;
| | - Jae-Hyuk Yu
- Department of Bacteriology, Food Research Institute, University of Wisconsin-Madison, Madison, WI 53706, USA;
| | - Hee-Soo Park
- Major in Food Biomaterials, School of Food Science and Biotechnology, Kyungpook National University, Daegu 41566, Republic of Korea;
- Department of Integrative Biology, Kyungpook National University, Daegu 41566, Republic of Korea
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2
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Liu N, Wang J, Yun Y, Wang J, Xu C, Wu S, Xu L, Li B, Kolodkin-Gal I, Dawood DH, Zhao Y, Ma Z, Chen Y. The NDR kinase-MOB complex FgCot1-Mob2 regulates polarity and lipid metabolism in Fusarium graminearum. Environ Microbiol 2021; 23:5505-5524. [PMID: 34347361 DOI: 10.1111/1462-2920.15698] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 07/28/2021] [Accepted: 07/29/2021] [Indexed: 01/08/2023]
Abstract
Members of the NDR (nuclear Dbf2-related) protein-kinase family are essential for cell differentiation and polarized morphogenesis. However, their functions in plant pathogenic fungi are not well understood. Here, we characterized the NDR kinase FgCot1 and its activator FgMob2 in Fusarium graminearum, a major pathogen causing Fusarium head blight (FHB) in wheat. FgCot1 and FgMob2 formed a NDR kinase-MOB protein complex. Localization assays using FgCot1-GFP or FgMob2-RFP constructs showed diverse subcellular localizations, including cytoplasm, septum, nucleus and hyphal tip. ΔFgcot1 and ΔFgmob2 exhibited serious defects in hyphal growth, polarity, fungal development and cell wall integrity as well as reduced virulence in planta. In contrast, lipid droplet accumulation was significantly increased in these two mutants. Phosphorylation of FgCot1 at two highly conserved residues (S462 and T630) as well as five new sites synergistically contributed its role in various cellular processes. In addition, non-synonymous mutations in two MAPK (mitogen-activated protein kinase) proteins, FgSte11 and FgGpmk1, partially rescued the growth defect of ΔFgmob2, indicating a functional link between the FgCot1-Mob2 complex and the FgGpmk1 signalling pathway in regulating filamentous fungal growth. These results indicated that the FgCot1-Mob2 complex is critical for polarity, fungal development, cell wall organization, lipid metabolism and virulence in F. graminearum.
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Affiliation(s)
- Na Liu
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, 310058, China.,Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Zhejiang University, Hangzhou, 310058, China.,College of Plant Health and Medicine, Qingdao Agricultural University, Qingdao, 266109, China
| | - Jing Wang
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, 310058, China.,Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Zhejiang University, Hangzhou, 310058, China
| | - Yingzi Yun
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, 310058, China.,Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Zhejiang University, Hangzhou, 310058, China
| | - Jinli Wang
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, 310058, China.,Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Zhejiang University, Hangzhou, 310058, China
| | - Chaoyun Xu
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, 310058, China.,Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Zhejiang University, Hangzhou, 310058, China
| | - Siqi Wu
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, 310058, China.,Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Zhejiang University, Hangzhou, 310058, China
| | - Luona Xu
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, 310058, China.,Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Zhejiang University, Hangzhou, 310058, China
| | - Baohua Li
- College of Plant Health and Medicine, Qingdao Agricultural University, Qingdao, 266109, China
| | - Ilana Kolodkin-Gal
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Dawood H Dawood
- Department of Agriculture Chemistry, Faculty of Agriculture, Mansoura University, Mansoura, 35516, Egypt
| | - Youfu Zhao
- Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Zhonghua Ma
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, 310058, China.,Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Zhejiang University, Hangzhou, 310058, China
| | - Yun Chen
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, 310058, China.,Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Zhejiang University, Hangzhou, 310058, China
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3
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Thammahong A, Dhingra S, Bultman KM, Kerkaert JD, Cramer RA. An Ssd1 Homolog Impacts Trehalose and Chitin Biosynthesis and Contributes to Virulence in Aspergillus fumigatus. mSphere 2019; 4:e00244-19. [PMID: 31068436 PMCID: PMC6506620 DOI: 10.1128/msphere.00244-19] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 04/24/2019] [Indexed: 12/24/2022] Open
Abstract
Regulation of fungal cell wall biosynthesis is critical to maintain cell wall integrity in dynamic fungal infection microenvironments. Genes involved in this response that impact fungal fitness and host immune responses remain to be fully defined. In this study, we observed that a yeast ssd1 homolog, ssdA, in the filamentous fungus Aspergillus fumigatus is involved in trehalose and cell wall homeostasis. An ssdA null mutant strain exhibited an increase in trehalose levels and a reduction in fungal colony growth rate. In contrast, overexpression of ssdA perturbed trehalose biosynthesis and reduced germination of conidia. The ssdA null mutant strain was more resistant to cell wall-perturbing agents, while overexpression of ssdA increased sensitivity. Overexpression of ssdA significantly increased chitin levels, and both loss and overexpression of ssdA altered subcellular localization of the class V chitin synthase CsmA. Strikingly, overexpression of ssdA abolished adherence to abiotic surfaces and severely attenuated the virulence of A. fumigatus in a murine model of invasive pulmonary aspergillosis. Despite the severe in vitro fitness defects observed upon loss of ssdA, neither surface adherence nor murine survival was impacted. In conclusion, A. fumigatus SsdA plays a critical role in cell wall homeostasis impacting A. fumigatus-host interactions.IMPORTANCE The incidence of life-threatening infections caused by the filamentous fungus Aspergillus fumigatus is increasing along with an increase in the number of fungal strains resistant to contemporary antifungal therapies. The fungal cell wall and the associated carbohydrates required for its synthesis and maintenance are attractive drug targets given that many genes encoding proteins involved in cell wall biosynthesis and integrity are absent in humans. Importantly, genes and associated cell wall biosynthesis and homeostasis regulatory pathways remain to be fully defined in A. fumigatus In this report, we identify SsdA as an important component of trehalose and fungal cell wall biosynthesis in A. fumigatus that consequently impacts the host immune response and fungal virulence in animal models of infection.
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Affiliation(s)
- Arsa Thammahong
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Sourabh Dhingra
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Katherine M Bultman
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Joshua D Kerkaert
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Robert A Cramer
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
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Herold I, Kowbel D, Delgado-Álvarez DL, Garduño-Rosales M, Mouriño-Pérez RR, Yarden O. Transcriptional profiling and localization of GUL-1, a COT-1 pathway component, in Neurospora crassa. Fungal Genet Biol 2019; 126:1-11. [PMID: 30731203 DOI: 10.1016/j.fgb.2019.01.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 01/23/2019] [Accepted: 01/23/2019] [Indexed: 01/19/2023]
Abstract
Impairment of theNeurospora crassaCOT-1 kinase results in defects in hyphal polarity. Some of these effects are partially suppressed by inactivation of gul-1 (encoding an mRNA-binding protein involved in translational regulation). Here, we report on the transcriptional profiling of cot-1 inactivation and demonstrate that gul-1 affects transcript abundance of multiple genes in the COT-1 pathway, including processes such as cell wall remodeling, nitrogen and amino acid metabolism. The GUL-1 protein itself was found to be distributed within the entire hyphal cell, along with a clear presence of aggregates that traffic within the cytoplasm. Live imaging of GUL-1-GFP demonstrated that GUL-1 transport is microtubule-dependent. Cellular stress, as imposed by the presence of the cell wall biosynthesis inhibitor Nikkomycin Z or by nitrogen limitation, resulted in a 2-3-fold increase of GUL-1 aggregate association with nuclei. Taken together, this study demonstrates that GUL-1 affects multiple processes, its function is stress-related and linked with cellular traffic and nuclear association.
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Affiliation(s)
- Inbal Herold
- Department of Plant Pathology and Microbiology, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 761001, Israel
| | - David Kowbel
- Plant & Microbial Biology, University of California, Berkeley, Berkeley, CA 94720-3102, USA
| | - Diego L Delgado-Álvarez
- Departamento de Microbiología, CICESE (Centro de Investigación Científica y Educación Superior de Ensenada), Mexico
| | - Marisela Garduño-Rosales
- Departamento de Microbiología, CICESE (Centro de Investigación Científica y Educación Superior de Ensenada), Mexico
| | - Rosa R Mouriño-Pérez
- Departamento de Microbiología, CICESE (Centro de Investigación Científica y Educación Superior de Ensenada), Mexico
| | - Oded Yarden
- Department of Plant Pathology and Microbiology, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 761001, Israel
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5
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Aharoni-Kats L, Zelinger E, Chen S, Yarden O. Altering Neurospora crassa MOB2A exposes its functions in development and affects its interaction with the NDR kinase COT1. Mol Microbiol 2018; 108:641-660. [PMID: 29600559 DOI: 10.1111/mmi.13954] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/15/2018] [Indexed: 12/30/2022]
Abstract
The Neurospora crassa Mps One Binder (MOB) proteins MOB2A and MOB2B physically interact with the Nuclear Dbf2 Related (NDR) kinase COT1 and have been shown to have overlapping functions in various aspects of asexual development. Here, we identified two N. crassa MOB2A residues, Tyr117 and Tyr119, which are potentially phosphorylated. Using phosphomimetic mob-2a mutants we have been able to establish that apart from their previously described roles, MOB2A/B are involved in additional developmental processes. Enhanced conidial germination, accompanied by conidial agglutination, in the phosphomimetic mutants indicated that MOB2A is a negative regulator of germination. Thick-section imaging of perithecia revealed slow maturation and a lack of asci alignment in the mutant strains demonstrating a role for MOB2A in sexual development. We demonstrate that even though MOB2A and MOB2B have some overlapping functions, MOB2B cannot compensate for the roles MOB2A has in conidiation and germination. Altering Tyr residues 117 and 119 impaired the physical interactions between MOB2A and COT1, most likely contributing to some of the observed effects. As cot-1 and the phosphomimetic mutants share an extragenic suppressor (gul-1), we concluded that at least some of the effects imposed by altering Tyr117 and Tyr119 are mediated by the NDR kinase.
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Affiliation(s)
- Liran Aharoni-Kats
- Department of Plant Pathology and Microbiology, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 7610000, Israel
| | - Einat Zelinger
- Centre for Scientific Imaging, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 7610000, Israel
| | - She Chen
- Proteomics Centre, The National Institute of Biological Sciences, Beijing 102206, China
| | - Oded Yarden
- Department of Plant Pathology and Microbiology, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 7610000, Israel
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6
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Kodama S, Ishizuka J, Miyashita I, Ishii T, Nishiuchi T, Miyoshi H, Kubo Y. The morphogenesis-related NDR kinase pathway of Colletotrichum orbiculare is required for translating plant surface signals into infection-related morphogenesis and pathogenesis. PLoS Pathog 2017; 13:e1006189. [PMID: 28146587 PMCID: PMC5305266 DOI: 10.1371/journal.ppat.1006189] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 02/13/2017] [Accepted: 01/18/2017] [Indexed: 01/27/2023] Open
Abstract
Plant infection by pathogenic fungi involves the differentiation of appressoria, specialized infection structures, initiated by fungal sensing and responding to plant surface signals. How plant fungal pathogens control infection-related morphogenesis in response to plant-derived signals has been unclear. Here we showed that the morphogenesis-related NDR kinase pathway (MOR) of the cucumber anthracnose fungus Colletotrichum orbiculare is crucial for appressorium development following perception of plant-derived signals. By screening of random insertional mutants, we identified that the MOR element CoPag1 (Perish-in-the-absence-of-GYP1) is a key component of the plant-derived signaling pathway involved in appressorium morphogenesis. Constitutive activation of the NDR kinase CoCbk1 (Cell-wall-biosynthesis-kinase-1) complemented copag1 defects. Furthermore, copag1 deletion impaired CoCbk1 phosphorylation, suggesting that CoPag1 functions via CoCbk1 activation. Searching for the plant signals that contribute to appressorium induction via MOR, we found that the cutin monomer n-octadecanal, degraded from the host cuticle by conidial esterases, functions as a signal molecule for appressorium development. Genome-wide transcriptional profiling during appressorium development revealed that MOR is responsible for the expression of a subset of the plant-signal-induced genes with potential roles in pathogenicity. Thus, MOR of C. orbiculare has crucial roles in regulating appressorium development and pathogenesis by communicating with plant-derived signals.
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Affiliation(s)
- Sayo Kodama
- Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, Japan
| | - Junya Ishizuka
- Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, Japan
| | - Ito Miyashita
- Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, Japan
| | - Takaaki Ishii
- Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, Japan
| | - Takumi Nishiuchi
- Division of Functional Genomics, Advanced Science Research Center, Kanazawa University, Kanazawa, Japan
| | - Hideto Miyoshi
- Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Yasuyuki Kubo
- Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, Japan
- * E-mail:
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7
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Harris SD. Branching of fungal hyphae: regulation, mechanisms and comparison with other branching systems. Mycologia 2017; 100:823-32. [DOI: 10.3852/08-177] [Citation(s) in RCA: 127] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Steven D. Harris
- Department of Plant Pathology and Center for Plant Science Innovation, University of Nebraska, Lincoln, Nebraska 68588
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8
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Schmidpeter J, Dahl M, Hofmann J, Koch C. ChMob2 binds to ChCbk1 and promotes virulence and conidiation of the fungal pathogen Colletotrichum higginsianum. BMC Microbiol 2017; 17:22. [PMID: 28103800 PMCID: PMC5248491 DOI: 10.1186/s12866-017-0932-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Accepted: 01/12/2017] [Indexed: 01/11/2023] Open
Abstract
Background Mob family proteins are conserved between animals, plants and fungi and are essential for the activation of NDR kinases that control crucial cellular processes like cytokinesis, proliferation and morphology. Results We identified a hypomorphic allele of ChMOB2 in a random insertional mutant (vir-88) of the hemibiotrophic ascomycete fungus Colletotrichum higginsianum. The mutant is impaired in conidiation, host penetration and virulence on Arabidopsis thaliana. ChMob2 binds to and co-localizes with the NDR/LATS kinase homolog ChCbk1. Mutants in the two potential ChCbk1 downstream targets ChSSD1 and ChACE2 show defects in pathogenicity. The genome of C. higginsianum encodes two more Mob proteins. While we could not detect any effect on pathogenicity in ΔChmob3 mutants, ChMob1 is involved in conidiation, septae formation and virulence. Conclusion This study shows that ChMob2 binds to the conserved NDR/LATS Kinase ChCbk1 and plays an important role in pathogenicity of Colletotrichum higginsianum on Arabidopsis thaliana. Electronic supplementary material The online version of this article (doi:10.1186/s12866-017-0932-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Johannes Schmidpeter
- Department of Biology, Division of Biochemistry, Friedrich-Alexander University Erlangen-Nuremberg, Staudtstrasse 5, 91058, Erlangen, Germany
| | - Marlis Dahl
- Department of Biology, Division of Biochemistry, Friedrich-Alexander University Erlangen-Nuremberg, Staudtstrasse 5, 91058, Erlangen, Germany
| | - Jörg Hofmann
- Department of Biology, Division of Biochemistry, Friedrich-Alexander University Erlangen-Nuremberg, Staudtstrasse 5, 91058, Erlangen, Germany
| | - Christian Koch
- Department of Biology, Division of Biochemistry, Friedrich-Alexander University Erlangen-Nuremberg, Staudtstrasse 5, 91058, Erlangen, Germany.
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Herold I, Yarden O. Regulation of Neurospora crassa cell wall remodeling via the cot-1 pathway is mediated by gul-1. Curr Genet 2016; 63:145-159. [PMID: 27363849 DOI: 10.1007/s00294-016-0625-z] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Revised: 06/14/2016] [Accepted: 06/16/2016] [Indexed: 11/29/2022]
Abstract
Impairment of the Neurospora crassa Nuclear DBF2-related kinase-encoding gene cot-1 results in pleiotropic effects, including abnormally thick hyphal cell walls and septa. An increase in the transcript abundance of genes encoding chitin and glucan synthases and the chitinase gh18-5, but not the cell wall integrity pathway transcription factor rlm-1, accompany the phenotypic changes observed. Deletion of chs-5 or chs-7 in a cot-1 background results in a reduction of hyperbranching frequency characteristic of the cot-1 parent. gul-1 (a homologue of the yeast SSD1 gene) encodes a translational regulator and has been shown to partially suppress cot-1. We demonstrate that the high expression levels of the cell wall remodeling genes analyzed is curbed, and reaches near wild type levels, when gul-1 is inactivated. This is accompanied by morphological changes that include reduced cell wall thickness and restoration of normal chitin levels. We conclude that gul-1 is a mediator of cell wall remodeling within the cot-1 pathway.
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Affiliation(s)
- Inbal Herold
- Department of Plant Pathology and Microbiology, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, 7610000, Rehovot, Israel
| | - Oded Yarden
- Department of Plant Pathology and Microbiology, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, 7610000, Rehovot, Israel.
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10
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De Souza CP, Hashmi SB, Osmani AH, Osmani SA. Application of a new dual localization-affinity purification tag reveals novel aspects of protein kinase biology in Aspergillus nidulans. PLoS One 2014; 9:e90911. [PMID: 24599037 PMCID: PMC3944740 DOI: 10.1371/journal.pone.0090911] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Accepted: 02/04/2014] [Indexed: 12/22/2022] Open
Abstract
Filamentous fungi occupy critical environmental niches and have numerous beneficial industrial applications but devastating effects as pathogens and agents of food spoilage. As regulators of essentially all biological processes protein kinases have been intensively studied but how they regulate the often unique biology of filamentous fungi is not completely understood. Significant understanding of filamentous fungal biology has come from the study of the model organism Aspergillus nidulans using a combination of molecular genetics, biochemistry, cell biology and genomic approaches. Here we describe dual localization-affinity purification (DLAP) tags enabling endogenous N or C-terminal protein tagging for localization and biochemical studies in A. nidulans. To establish DLAP tag utility we endogenously tagged 17 protein kinases for analysis by live cell imaging and affinity purification. Proteomic analysis of purifications by mass spectrometry confirmed association of the CotA and NimXCdk1 kinases with known binding partners and verified a predicted interaction of the SldABub1/R1 spindle assembly checkpoint kinase with SldBBub3. We demonstrate that the single TOR kinase of A. nidulans locates to vacuoles and vesicles, suggesting that the function of endomembranes as major TOR cellular hubs is conserved in filamentous fungi. Comparative analysis revealed 7 kinases with mitotic specific locations including An-Cdc7 which unexpectedly located to mitotic spindle pole bodies (SPBs), the first such localization described for this family of DNA replication kinases. We show that the SepH septation kinase locates to SPBs specifically in the basal region of apical cells in a biphasic manner during mitosis and again during septation. This results in gradients of SepH between G1 SPBs which shift along hyphae as each septum forms. We propose that SepH regulates the septation initiation network (SIN) specifically at SPBs in the basal region of G1 cells and that localized gradients of SIN activity promote asymmetric septation.
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Affiliation(s)
- Colin P. De Souza
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio, United States of America
| | - Shahr B. Hashmi
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio, United States of America
| | - Aysha H. Osmani
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio, United States of America
| | - Stephen A. Osmani
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio, United States of America
- * E-mail:
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11
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Ziv C, Feldman D, Aharoni-Kats L, Chen S, Liu Y, Yarden O. The N-terminal region of the Neurospora NDR kinase COT1 regulates morphology via its interactions with MOB2A/B. Mol Microbiol 2013; 90:383-99. [PMID: 23962317 DOI: 10.1111/mmi.12371] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/16/2013] [Indexed: 12/15/2022]
Abstract
Nuclear Dbf2p-related (NDR) protein kinases are important for cell differentiation and polar morphogenesis in various organisms, yet some of their functions are still elusive. Dysfunction of the Neurospora crassa NDR kinase COT1 leads to cessation of tip extension and hyperbranching. NDR kinases require the physical interaction between the kinase's N-terminal region (NTR) and the MPS1-binding (MOB) proteins for their activity and functions. To study the interactions between COT1 and MOB2 proteins, we mutated several conserved residues and a novel phosphorylation site within the COT1 NTR. The phenotypes of these mutants suggest that the NTR is required for COT1 functions in regulating hyphal elongation and branching, asexual conidiation and germination. Interestingly, while both MOB2A and MOB2B promote proper hyphal growth, they have distinct COT1-dependent roles in regulation of macroconidiation. Immunoprecipitation experiments indicate physical association of COT1 with both MOB2A and MOB2B, simultaneously. Furthermore, the binding of the two MOB2 proteins to COT1 is mediated by different residues at the COT1 NTR, suggesting a hetero-trimer is formed. Thus, although MOB2A/B may have some overlapping functions in regulating hyphal tip extension, their function is not redundant and they are both required for proper fungal development.
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Affiliation(s)
- Carmit Ziv
- Department of Plant Pathology and Microbiology, The Otto Warburg Minerva Center for Agricultural Biotechnology, Faculty of Agricultural, Food and Environmental Quality Sciences, The Hebrew University of Jerusalem, Rehovot, 76100, Israel
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12
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Sartorel E, Pérez-Martín J. The distinct interaction between cell cycle regulation and the widely conserved morphogenesis-related (MOR) pathway in the fungus Ustilago maydis determines morphology. J Cell Sci 2012; 125:4597-608. [PMID: 22767510 DOI: 10.1242/jcs.107862] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The morphogenesis-related NDR kinase (MOR) pathway regulates morphogenesis in fungi. In spite of the high conservation of its components, impairing their functions results in highly divergent cellular responses depending on the fungal species. The reasons for such differences are unclear. Here we propose that the species-specific connections between cell cycle regulation and the MOR pathway could be partly responsible for these divergences. We based our conclusion on the characterization of the MOR pathway in the fungus Ustilago maydis. Each gene that encodes proteins of this pathway in U. maydis was deleted. All mutants exhibited a constitutive hyperpolarized growth, contrasting with the loss of polarity observed in other fungi. Using a conditional allele of the central NDR kinase Ukc1, we found that impairing MOR function resulted in a prolonged G2 phase. This cell cycle delay appears to be the consequence of an increase in Cdk1 inhibitory phosphorylation. Strikingly, prevention of the inhibitory Cdk1 phosphorylation abolished the hyperpolarized growth associated with MOR pathway depletion. We found that the prolonged G2 phase resulted in higher levels of expression of crk1, a conserved kinase that promotes polar growth in U. maydis. Deletion of crk1 also abolished the dramatic activation of polar growth in cells lacking the MOR pathway. Taken together, our results suggest that Cdk1 inhibitory phosphorylation may act as an integrator of signaling cascades regulating fungal morphogenesis and that the distinct morphological response observed in U. maydis upon impairment of the MOR pathway could be due to a cell cycle deregulation.
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Affiliation(s)
- Elodie Sartorel
- Instituto de Biología Funcional y Genómica (CSIC), 37007 Salamanca, Spain
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Tales of RAM and MOR: NDR kinase signaling in fungal morphogenesis. Curr Opin Microbiol 2010; 13:663-71. [DOI: 10.1016/j.mib.2010.08.010] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2010] [Accepted: 08/30/2010] [Indexed: 02/04/2023]
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14
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Ziv C, Kra-Oz G, Gorovits R, März S, Seiler S, Yarden O. Cell elongation and branching are regulated by differential phosphorylation states of the nuclear Dbf2-related kinase COT1 in Neurospora crassa. Mol Microbiol 2009; 74:974-89. [PMID: 19818014 DOI: 10.1111/j.1365-2958.2009.06911.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Dysfunction of the Neurospora crassa nuclear Dbf2-related kinase COT1 leads to cessation of tip extension and massive induction of new sites of growth. To determine the role phosphorylation plays in COT1 function, we mutated COT1 residues corresponding to positions of highly conserved nuclear Dbf2-related phosphorylation sites. Analyses of the point-mutation cot-1 strains (mimicking non- and constitutively phosphorylated states) indicate the involvement of COT1 phosphorylation in the regulation of hyphal elongation and branching as well as asexual development by altering cell wall integrity and actin organization. Phosphorylation of COT1's activation segment (at Ser417) is required for proper in vitro kinase activity, but has only a limited effect on hyphal growth. In marked contrast, even though phosphorylation of the C-terminal hydrophobic motif (at Thr589) is crucial for all COT1 functions in vivo, the lack of Thr589 phosphorylation did not significantly affect in vitro COT1 kinase activity. Nevertheless, its regulatory role has been made evident by the significant increase observed in COT1 kinase activity when this residue was substituted in a manner mimicking constitutive phosphorylation. We conclude that COT1 regulates elongation and branching in an independent manner, which is determined by its phosphorylation state.
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Affiliation(s)
- Carmit Ziv
- Department of Plant Pathology and Microbiology, The Otto Warburg Minerva Center for Agricultural Biotechnology, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel
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Shi J, Chen W, Liu Q, Chen S, Hu H, Turner G, Lu L. Depletion of the MobB and CotA complex in Aspergillus nidulans causes defects in polarity maintenance that can be suppressed by the environment stress. Fungal Genet Biol 2008; 45:1570-81. [DOI: 10.1016/j.fgb.2008.08.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2008] [Revised: 08/18/2008] [Accepted: 08/19/2008] [Indexed: 11/30/2022]
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Song Y, Cheon SA, Lee KE, Lee SY, Lee BK, Oh DB, Kang HA, Kim JY. Role of the RAM network in cell polarity and hyphal morphogenesis in Candida albicans. Mol Biol Cell 2008; 19:5456-77. [PMID: 18843050 DOI: 10.1091/mbc.e08-03-0272] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
RAM (regulation of Ace2p transcription factor and polarized morphogenesis) is a conserved signaling network that regulates polarized morphogenesis in yeast, worms, flies, and humans. To investigate the role of the RAM network in cell polarity and hyphal morphogenesis of Candida albicans, each of the C. albicans RAM genes (CaCBK1, CaMOB2, CaKIC1, CaPAG1, CaHYM1, and CaSOG2) was deleted. All C. albicans RAM mutants exhibited hypersensitivity to cell-wall- or membrane-perturbing agents, exhibiting cell-separation defects, a multinucleate phenotype and loss of cell polarity. Yeast two-hybrid and in vivo functional analyses of CaCbk1p and its activator, CaMob2p, the key factors in the RAM network, demonstrated that the direct interaction between the SMA domain of CaCbk1p and the Mob1/phocein domain of CaMob2p was necessary for hyphal growth of C. albicans. Genome-wide transcription profiling of a Camob2 mutant suggested that the RAM network played a role in serum- and antifungal azoles-induced activation of ergosterol biosynthesis genes, especially those involved in the late steps of ergosterol biosynthesis, and might be associated, at least indirectly, with the Tup1p-Nrg1p pathway. Collectively, these results demonstrate that the RAM network is critically required for hyphal growth as well as normal vegetative growth in C. albicans.
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Affiliation(s)
- Yunkyoung Song
- Department of Microbiology, School of Bioscience and Biotechnology, Chungnam National University, Daejeon 305-764, Korea
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