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Ornelas-Llamas MM, Pérez-Mozqueda LL, Callejas-Negrete OA, Castro-Longoria E. RHO-3 plays a significant role in hyphal extension rate, conidiation, and the integrity of the Spitzenkörper in Neurospora crassa. Fungal Genet Biol 2024; 171:103873. [PMID: 38266703 DOI: 10.1016/j.fgb.2024.103873] [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: 11/01/2023] [Revised: 01/19/2024] [Accepted: 01/20/2024] [Indexed: 01/26/2024]
Abstract
The Rho family of monomeric GTPases act as signaling proteins to establish and maintain cell polarity and other essential cellular processes. Rho3 is a GTPase of the Rho family that is exclusive of fungi that regulate cell polarity in yeast. However, studies have yet to explore its function in filamentous fungi. In this work, we investigated the role of RHO-3 in the model organism Neurospora crassa. Confocal microscopy analysis revealed that RHO-3 localizes in the outer region of the Spitzenkörper (Spk), in the plasma membrane from region II to the beginning of region III, and in the septa of mature hyphae. The phenotypic effect of the rho-3 deletion was analyzed. The results revealed that the rho-3 null strain showed severe defects in growth rate, aerial hyphae length, and conidia production. The organization of the Spk is also affected in the absence of RHO-3. Co-expression analysis of GFP-RHO-3 with glucan synthase 1 (GS-1-mChFP) and chitin synthase 1 (CHS-1-mChFP) revealed that RHO-3 localizes in the external region of the Spk in the macrovesicles zone. In summary, our results suggest that RHO-3 is not essential for the polarized growth of hyphae but plays a significant role in hyphal extension rate, conidiation, sexual reproduction and the integrity of the Spk, possibly regulating the delivery of macrovesicles to the apical dome.
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Affiliation(s)
- Martha M Ornelas-Llamas
- Department of Microbiology, Center for Scientific Research and Higher Education of Ensenada (CICESE), Ensenada, Baja California, Mexico
| | - Luis L Pérez-Mozqueda
- Department of Microbiology, Center for Scientific Research and Higher Education of Ensenada (CICESE), Ensenada, Baja California, Mexico; Center for Wine and Vine Studies (CEVIT), Technical and Higher Education Center (CETYS), Ensenada, Baja California, Mexico
| | - Olga A Callejas-Negrete
- Department of Microbiology, Center for Scientific Research and Higher Education of Ensenada (CICESE), Ensenada, Baja California, Mexico
| | - Ernestina Castro-Longoria
- Department of Microbiology, Center for Scientific Research and Higher Education of Ensenada (CICESE), Ensenada, Baja California, Mexico.
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2
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Cui FJ, Yang YM, Sun L, Zan XY, Sun WJ, Zeb U. Grifola frondosa polysaccharides: A review on structure/activity, biosynthesis and engineering strategies. Int J Biol Macromol 2024; 257:128584. [PMID: 38056754 DOI: 10.1016/j.ijbiomac.2023.128584] [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: 06/28/2023] [Revised: 11/17/2023] [Accepted: 12/01/2023] [Indexed: 12/08/2023]
Abstract
Polysaccharides are the main polymers in edible fungi Grifola frondosa, playing a crucial role in the physiology and representing the healthy benefits for humans. Recent efforts have well elucidated the fine structures and biological functions of G. frondosa polysaccharides. The recently-rapid developments and increasing availability in fungal genomes also accelerated the better understanding of key genes and pathways involved in biosynthesis of G. frondosa polysaccharides. Herein, we provide a brief overview of G. frondosa polysaccharides and their activities, and comprehensively outline the complex process, genes and proteins corresponding to G. frondosa polysaccharide biosynthesis. The regulation strategies including strain improvement, process optimization and genetic engineering were also summarized for maximum production of G. frondosa polysaccharides. Some remaining unanswered questions in describing the fine synthesis machinery were also pointed out to open up new avenues for answering the structure-activity relationship and improving polysaccharide biosynthesis in G. frondosa. The review hopefully presents a reasonable full picture of activities, biosynthesis, and production regulation of polysaccharide in G. frondosa.
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Affiliation(s)
- Feng-Jie Cui
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, PR China; Jiangxi Provincial Engineering and Technology Center for Food Additives Bio-production, Dexing 334221, PR China.
| | - Yu-Meng Yang
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, PR China
| | - Lei Sun
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, PR China
| | - Xin-Yi Zan
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, PR China
| | - Wen-Jing Sun
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, PR China; Jiangxi Provincial Engineering and Technology Center for Food Additives Bio-production, Dexing 334221, PR China
| | - Umar Zeb
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, PR China
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3
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Liu J, Wang C, Kong L, Yang Y, Cui X, Li K, Nian H. Rho2 involved in development, stress response and pathogenicity of Fusarium oxysporum. World J Microbiol Biotechnol 2023; 39:272. [PMID: 37548840 DOI: 10.1007/s11274-023-03720-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 08/02/2023] [Indexed: 08/08/2023]
Abstract
Rho GTPases regulate the activity of cell wall biosynthesis, actin assembly and polar cell secretion. However, the function of Rho GTPase in filamentous fungi is poorly understood. To understand the role of Rho2 GTPase in Fusarium oxysporum, which is one of root rot pathogens of Panax notoginseng, △rho2 mutant was constructed. Phenotypes of △rho2, including conidiation, germination of spores, stresses (osmotic-, cell membrane-, cell wall disturbing-, metal-, and high temperature-) tolerance and pathogenicity were analyzed. The results showed that the growth of △rho2 was destroyed under cell wall disturbing stress and high temperature stress, suggesting that Rho2 regulated the response of F. oxysporum to cell wall synthesis inhibitors and high temperature stress. Germination of spores and pathogenicity to P. notoginseng were reduced in △rho2 mutant. Western blot results showed that rho2 deletion increased the phosphorylation level of Mpk1. To identify genes regulated by Rho2, transcriptome sequencing was carried out. 2477 genes were identified as upregulated genes and 2177 genes were identified as downregulated genes after rho2 was deleted. These genes provide clues for further study of rho2 function.
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Affiliation(s)
- Jia Liu
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, 650500, China
| | - Chengsong Wang
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, 650500, China
| | - Lei Kong
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, 650500, China
| | - Ye Yang
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, 650500, China
- Key Laboratory of Panax notoginseng Resources Sustainable Development and Utilization of State Administration of Traditional Chinese Medicine, Kunming, 650500, China
| | - Xiuming Cui
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, 650500, China
- Key Laboratory of Panax notoginseng Resources Sustainable Development and Utilization of State Administration of Traditional Chinese Medicine, Kunming, 650500, China
| | - Kunzhi Li
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, 650500, China
| | - Hongjuan Nian
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, 650500, China.
- Key Laboratory of Panax notoginseng Resources Sustainable Development and Utilization of State Administration of Traditional Chinese Medicine, Kunming, 650500, China.
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4
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The Small Ras Superfamily GTPase Rho4 of the Maize Anthracnose Fungus Colletotrichum graminicola Is Required for β-1,3-glucan Synthesis, Cell Wall Integrity, and Full Virulence. J Fungi (Basel) 2022; 8:jof8100997. [PMID: 36294561 PMCID: PMC9604917 DOI: 10.3390/jof8100997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 09/14/2022] [Accepted: 09/14/2022] [Indexed: 11/17/2022] Open
Abstract
Small Ras superfamily GTPases are highly conserved regulatory factors of fungal cell wall biosynthesis and morphogenesis. Previous experiments have shown that the Rho4-like protein of the maize anthracnose fungus Colletotrichum graminicola, formerly erroneously annotated as a Rho1 protein, physically interacts with the β-1,3-glucan synthase Gls1 (Lange et al., 2014; Curr. Genet. 60:343–350). Here, we show that Rho4 is required for β-1,3-glucan synthesis. Accordingly, Δrho4 strains formed distorted vegetative hyphae with swellings, and exhibited strongly reduced rates of hyphal growth and defects in asexual sporulation. Moreover, on host cuticles, conidia of Δrho4 strains formed long hyphae with hyphopodia, rather than short germ tubes with appressoria. Hyphopodia of Δrho4 strains exhibited penetration defects and often germinated laterally, indicative of cell wall weaknesses. In planta differentiated infection hyphae of Δrho4 strains were fringy, and anthracnose disease symptoms caused by these strains on intact and wounded maize leaf segments were significantly weaker than those caused by the WT strain. A retarded disease symptom development was confirmed by qPCR analyses. Collectively, we identified the Ras GTPase Rho4 as a new virulence factor of C. graminicola.
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Stage-Specific Genetic Interaction between FgYCK1 and FgBNI4 during Vegetative Growth and Conidiation in Fusarium graminearum. Int J Mol Sci 2022; 23:ijms23169106. [PMID: 36012372 PMCID: PMC9408904 DOI: 10.3390/ijms23169106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 08/09/2022] [Accepted: 08/12/2022] [Indexed: 11/26/2022] Open
Abstract
CK1 casein kinases are well conserved in filamentous fungi. However, their functions are not well characterized in plant pathogens. In Fusarium graminearum, deletion of FgYCK1 caused severe growth defects and loss of conidiation, fertility, and pathogenicity. Interestingly, the Fgyck1 mutant was not stable and often produced fast-growing spontaneous suppressors. Suppressor mutations were frequently identified in the FgBNI4 gene by sequencing analyses. Deletion of the entire FgBNI4 or disruptions of its conserved C-terminal region could suppress the defects of Fgyck1 in hyphal growth and conidiation, indicating the genetic relationship between FgYCK1 and FgBNI4. Furthermore, the Fgyck1 mutant showed defects in polarized growth, cell wall integrity, internalization of FgRho1 and vacuole fusion, which were all partially suppressed by deletion of FgBNI4. Overall, our results indicate a stage-specific functional relationship between FgYCK1 and FgBNI4, possibly via FgRho1 signaling for regulating polarized hyphal growth and cell wall integrity.
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Transcriptomic Analysis Reveals That Rho GTPases Regulate Trap Development and Lifestyle Transition of the Nematode-Trapping Fungus Arthrobotrys oligospora. Microbiol Spectr 2022; 10:e0175921. [PMID: 35019695 PMCID: PMC8754127 DOI: 10.1128/spectrum.01759-21] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Nematode-trapping (NT) fungi can form unique infection structures (traps) to capture and kill free-living nematodes and, thus, can play a potential role in the biocontrol of nematodes. Arthrobotrys oligospora is a representative species of NT fungi. Here, we performed a time course transcriptome sequencing (RNA-seq) analysis of transcriptomes to understand the global gene expression levels of A. oligospora during trap formation and predation. We identified 5,752 unique differentially expressed genes, among which the rac gene was significantly upregulated. Alternative splicing events occurred in 2,012 genes, including the rac and rho2 gene. Furthermore, we characterized three Rho GTPases (Rho2, Rac, and Cdc42) in A. oligospora using gene disruption and multiphenotypic analysis. Our analyses showed that AoRac and AoCdc42 play an important role in mycelium growth, lipid accumulation, DNA damage, sporulation, trap formation, pathogenicity, and stress response in A. oligospora. AoCdc42 and AoRac specifically interacted with components of the Nox complex, thus regulating the production of reactive oxygen species. Moreover, the transcript levels of several genes associated with protein kinase A, mitogen-activated protein kinase, and p21-activated kinase were also altered in the mutants, suggesting that Rho GTPases might function upstream from these kinases. This study highlights the important role of Rho GTPases in A. oligospora and provides insights into the regulatory mechanisms of signaling pathways in the trap morphogenesis and lifestyle transition of NT fungi. IMPORTANCE Nematode-trapping (NT) fungi are widely distributed in terrestrial and aquatic ecosystems. Their broad adaptability and flexible lifestyles make them ideal agents for controlling pathogenic nematodes. Arthrobotrys oligospora is a model species employed for understanding the interaction between fungi and nematodes. Here, we revealed that alternative splicing events play a crucial role in the trap development and lifestyle transition in A. oligospora. Furthermore, Rho GTPases exert differential effects on the growth, development, and pathogenicity of A. oligospora. In particular, AoRac is required for sporulation and trap morphogenesis. In addition, our analysis showed that Rho GTPases regulate the production of reactive oxygen species and function upstream from several kinases. Collectively, these results expand our understanding of gene expression and alternative splicing events in A. oligospora and the important roles of Rho GTPases in NT fungi, thereby providing a foundation for exploring their potential application in the biocontrol of pathogenic nematodes.
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7
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Plaza V, Silva-Moreno E, Castillo L. Breakpoint: Cell Wall and Glycoproteins and their Crucial Role in the Phytopathogenic Fungi Infection. Curr Protein Pept Sci 2021; 21:227-244. [PMID: 31490745 DOI: 10.2174/1389203720666190906165111] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 08/02/2019] [Accepted: 08/17/2019] [Indexed: 01/09/2023]
Abstract
The cell wall that surrounds fungal cells is essential for their survival, provides protection against physical and chemical stresses, and plays relevant roles during infection. In general, the fungal cell wall is composed of an outer layer of glycoprotein and an inner skeletal layer of β-glucans or α- glucans and chitin. Chitin synthase genes have been shown to be important for septum formation, cell division and virulence. In the same way, chitin can act as a potent elicitor to activate defense response in several plant species; however, the fungi can convert chitin to chitosan during plant infection to evade plant defense mechanisms. Moreover, α-1,3-Glucan, a non-degradable polysaccharide in plants, represents a key feature in fungal cell walls formed in plants and plays a protective role for this fungus against plant lytic enzymes. A similar case is with β-1,3- and β-1,6-glucan which are essential for infection, structure rigidity and pathogenicity during fungal infection. Cell wall glycoproteins are also vital to fungi. They have been associated with conidial separation, the increase of chitin in conidial cell walls, germination, appressorium formation, as well as osmotic and cell wall stress and virulence; however, the specific roles of glycoproteins in filamentous fungi remain unknown. Fungi that can respond to environmental stimuli distinguish these signals and relay them through intracellular signaling pathways to change the cell wall composition. They play a crucial role in appressorium formation and penetration, and release cell wall degrading enzymes, which determine the outcome of the interaction with the host. In this review, we highlight the interaction of phypatophogen cell wall and signaling pathways with its host and their contribution to fungal pathogenesis.
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Affiliation(s)
- Verónica Plaza
- Laboratorio de Biología Molecular y Bioquímica, Departamento de Biología, Universidad de La Serena, La Serena, Chile
| | - Evelyn Silva-Moreno
- Instituto de Ciencias Biomédicas, Universidad Autónoma de Chile, Temuco, Chile
| | - Luis Castillo
- Laboratorio de Biología Molecular y Bioquímica, Departamento de Biología, Universidad de La Serena, La Serena, Chile
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8
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Spitzenkörper assembly mechanisms reveal conserved features of fungal and metazoan polarity scaffolds. Nat Commun 2020; 11:2830. [PMID: 32503980 PMCID: PMC7275032 DOI: 10.1038/s41467-020-16712-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 05/14/2020] [Indexed: 02/08/2023] Open
Abstract
The Spitzenkörper (SPK) constitutes a collection of secretory vesicles and polarity-related proteins intimately associated with polarized growth of fungal hyphae. Many SPK-localized proteins are known, but their assembly and dynamics remain poorly understood. Here, we identify protein-protein interaction cascades leading to assembly of two SPK scaffolds and recruitment of diverse effectors in Neurospora crassa. Both scaffolds are transported to the SPK by the myosin V motor (MYO-5), with the coiled-coil protein SPZ-1 acting as cargo adaptor. Neither scaffold appears to be required for accumulation of SPK secretory vesicles. One scaffold consists of Leashin-2 (LAH-2), which is required for SPK localization of the signalling kinase COT-1 and the glycolysis enzyme GPI-1. The other scaffold comprises a complex of Janus-1 (JNS-1) and the polarisome protein SPA-2. Via its Spa homology domain (SHD), SPA-2 recruits a calponin domain-containing F-actin effector (CCP-1). The SHD NMR structure reveals a conserved surface groove required for effector binding. Similarities between SPA-2/JNS-1 and the metazoan GIT/PIX complex identify foundational features of the cell polarity apparatus that predate the fungal-metazoan divergence. The Spitzenkörper (SPK) is a polarized accumulation of proteins and secretory vesicles associated with tip growth of fungal hyphae. Here, Zheng et al. study SPK assembly and dynamics, identify SPK protein scaffolds and associated proteins, and reveal similarities with other scaffolds from metazoans.
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9
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Shao J, Wang L, Liu Y, Qi Q, Wang B, Lu S, Liu C. Identification of milRNAs and their target genes in Ganoderma lucidum by high-throughput sequencing and degradome analysis. Fungal Genet Biol 2020; 136:103313. [DOI: 10.1016/j.fgb.2019.103313] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 08/09/2019] [Accepted: 11/15/2019] [Indexed: 12/15/2022]
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10
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Wagener J, Striegler K, Wagener N. α- and β-1,3-Glucan Synthesis and Remodeling. Curr Top Microbiol Immunol 2020; 425:53-82. [PMID: 32193600 DOI: 10.1007/82_2020_200] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Glucans are characteristic and major constituents of fungal cell walls. Depending on the species, different glucan polysaccharides can be found. These differ in the linkage of the D-glucose monomers which can be either in α- or β-conformation and form 1,3, 1,4 or 1,6 O-glycosidic bonds. The linkages and polymer lengths define the physical properties of the glucan macromolecules, which may form a scaffold for other cell wall structures and influence the rigidity and elasticity of the wall. β-1,3-glucan is essential for the viability of many fungal pathogens. Therefore, the β-1,3-glucan synthase complex represents an excellent and primary target structure for antifungal drugs. Fungal cell wall β-glucan is also an important pathogen-associated molecular pattern (PAMP). To hide from innate immunity, many fungal pathogens depend on the synthesis of cell wall α-glucan, which functions as a stealth molecule to mask the β-glucans itself or links other masking structures to the cell wall. Here, we review the current knowledge about the biosynthetic machineries that synthesize β-1,3-glucan, β-1,6-glucan, and α-1,3-glucan. We summarize the discovery of the synthases, major regulatory traits, and the impact of glucan synthesis deficiencies on the fungal organisms. Despite all efforts, many aspects of glucan synthesis remain yet unresolved, keeping research directed toward cell wall biogenesis an exciting and continuously challenging topic.
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Affiliation(s)
- Johannes Wagener
- Institut Für Hygiene Und Mikrobiologie, University of Würzburg, Würzburg, Germany. .,National Reference Center for Invasive Fungal Infections (NRZMyk), Jena, Germany.
| | - Kristina Striegler
- Institut Für Hygiene Und Mikrobiologie, University of Würzburg, Würzburg, Germany
| | - Nikola Wagener
- Department of Cell Biology, Medical Faculty, University of Munich, Martinsried, Germany
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Patel PK, Free SJ. The Genetics and Biochemistry of Cell Wall Structure and Synthesis in Neurospora crassa, a Model Filamentous Fungus. Front Microbiol 2019; 10:2294. [PMID: 31649638 PMCID: PMC6796803 DOI: 10.3389/fmicb.2019.02294] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 09/20/2019] [Indexed: 01/25/2023] Open
Abstract
This review discusses the wealth of information available for the N. crassa cell wall. The basic organization and structure of the cell wall is presented and how the wall changes during the N. crassa life cycle is discussed. Over forty cell wall glycoproteins have been identified by proteomic analyses. Genetic and biochemical studies have identified many of the key enzymes needed for cell wall biogenesis, and the roles these enzymes play in cell wall biogenesis are discussed. The review includes a discussion of how the major cell wall components (chitin, β-1,3-glucan, mixed β-1,3-/ β-1,4- glucans, glycoproteins, and melanin) are synthesized and incorporated into the cell wall. We present a four-step model for how cell wall glycoproteins are covalently incorporated into the cell wall. In N. crassa, the covalent incorporation of cell wall glycoproteins into the wall occurs through a glycosidic linkage between lichenin (a mixed β-1,3-/β-1,4- glucan) and a "processed" galactomannan that has been attached to the glycoprotein N-linked oligosaccharides. The first step is the addition of the galactomannan to the N-linked oligosaccharide. Mutants affected in galactomannan formation are unable to incorporate glycoproteins into their cell walls. The second step is carried out by the enzymes from the GH76 family of α-1,6-mannanases, which cleave the galactomannan to generate a processed galactomannan. The model suggests that the third and fourth steps are carried out by members of the GH72 family of glucanosyltransferases. In the third step the glucanosyltransferases cleave lichenin and generate enzyme/substrate intermediates in which the lichenin is covalently attached to the active site of the glucanosyltransferases. In the final step, the glucanosyltransferases attach the lichenin onto the processed galactomannans, which creates new glycosidic bonds and effectively incorporates the glycoproteins into the cross-linked cell wall glucan/chitin matrix.
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Affiliation(s)
| | - Stephen J. Free
- Department of Biological Sciences, SUNY University at Buffalo, Buffalo, NY, United States
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Verdín J, Sánchez-León E, Rico-Ramírez AM, Martínez-Núñez L, Fajardo-Somera RA, Riquelme M. Off the wall: The rhyme and reason of Neurospora crassa hyphal morphogenesis. ACTA ACUST UNITED AC 2019; 5:100020. [PMID: 32743136 PMCID: PMC7389182 DOI: 10.1016/j.tcsw.2019.100020] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 02/07/2019] [Accepted: 02/10/2019] [Indexed: 12/11/2022]
Abstract
Chitin and β-1,3-glucan synthases are transported separately in chitosomes and macrovesicles. Chitin synthases occupy the core of the SPK; β-1,3-glucan synthases the outer layer. CHS-4 arrival to the SPK and septa is CSE-7 dependent. Rabs YPT-1 and YPT-31 localization at the SPK mimics that of chitosomes and macrovesicles. The exocyst acts as a tether between the SPK outer layer vesicles and the apical PM.
The fungal cell wall building processes are the ultimate determinants of hyphal shape. In Neurospora crassa the main cell wall components, β-1,3-glucan and chitin, are synthesized by enzymes conveyed by specialized vesicles to the hyphal tip. These vesicles follow different secretory routes, which are delicately coordinated by cargo-specific Rab GTPases until their accumulation at the Spitzenkörper. From there, the exocyst mediates the docking of secretory vesicles to the plasma membrane, where they ultimately get fused. Although significant progress has been done on the cellular mechanisms that carry cell wall synthesizing enzymes from the endoplasmic reticulum to hyphal tips, a lot of information is still missing. Here, the current knowledge on N. crassa cell wall composition and biosynthesis is presented with an emphasis on the underlying molecular and cellular secretory processes.
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Key Words
- BGT, β-1,3-glucan transferases
- CHS, chitin synthase
- CLSM, confocal laser scanning microscopy
- CWI, cell wall integrity
- CWP, cell wall proteins
- Cell wall
- ER, endoplasmic reticulum
- FRAP, fluorescence recovery after photobleaching
- GEF, guanine nucleotide exchange factor
- GFP, green fluorescent protein
- GH, glycosyl hydrolases
- GPI, glycosylphosphatidylinositol
- GSC, β-1,3-glucan synthase complex
- MMD, myosin-like motor domain
- MS, mass spectrometry
- MT, microtubule
- NEC, network of elongated cisternae
- PM, plasma membrane
- SPK, Spitzenkörper
- Spitzenkörper
- TIRFM, total internal reflection fluorescence microscopy
- TM, transmembrane
- Tip growth
- Vesicles
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Affiliation(s)
- Jorge Verdín
- Industrial Biotechnology, CIATEJ-Jalisco State Scientific Research and Technology Assistance Center, Mexico National Council for Science and Technology, Zapopan, Jalisco, Mexico
| | - Eddy Sánchez-León
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada
| | - Adriana M Rico-Ramírez
- Department of Microbiology, Centro de Investigación Científica y de Educación Superior de Ensenada, CICESE Ensenada, Baja California, Mexico
| | - Leonora Martínez-Núñez
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Rosa A Fajardo-Somera
- Karlsruhe Institute of Technology (KIT) South Campus, Institute for Applied Biosciences, Department of Microbiology, Karlsruhe, Germany
| | - Meritxell Riquelme
- Department of Microbiology, Centro de Investigación Científica y de Educación Superior de Ensenada, CICESE Ensenada, Baja California, Mexico
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Fu T, Kim JO, Han JH, Gumilang A, Lee YH, Kim KS. A Small GTPase RHO2 Plays an Important Role in Pre-infection Development in the Rice Blast Pathogen Magnaporthe oryzae. THE PLANT PATHOLOGY JOURNAL 2018; 34:470-479. [PMID: 30588220 PMCID: PMC6305172 DOI: 10.5423/ppj.oa.04.2018.0069] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Revised: 08/17/2018] [Accepted: 08/21/2018] [Indexed: 05/15/2023]
Abstract
The rice blast pathogen Magnaporthe oryzae is a global threat to rice production. Here we characterized RHO2 gene (MGG_02457) that belongs to the Rho GTPase family, using a deletion mutant. This mutant ΔMorho2 exhibited no defects in conidiation and germination but developed only 6% of appressoria in response to a hydrophobic surface when compared to the wild-type progenitor. This result indicates that MoRHO2 plays a role in appressorium development. Furthermore, exogenous cAMP treatment on the mutant led to appressoria that exhibited abnormal morphology on both hydrophobic and hydrophilic surfaces. These outcomes suggested the involvement of MoRHO2 in cAMP-mediated appressorium development. ΔMorho2 mutation also delayed the development of appressorium-like structures (ALS) at hyphal tips on hydrophobic surface, which were also abnormally shaped. These results suggested that MoRHO2 is involved in morphological development of appressoria and ALS from conidia and hyphae, respectively. As expected, ΔMorho2 mutant was defective in plant penetration, but was still able to cause lesions, albeit at a reduced rate on wounded plants. These results implied that MoRHO2 plays a role in M. oryzae virulence as well.
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Affiliation(s)
- Teng Fu
- Division of Bioresource Sciences, and Bioherb Research Institute, Kangwon National University, Chuncheon 24341,
Korea
| | - Joon-Oh Kim
- Division of Bioresource Sciences, and Bioherb Research Institute, Kangwon National University, Chuncheon 24341,
Korea
| | - Joon-Hee Han
- Division of Bioresource Sciences, and Bioherb Research Institute, Kangwon National University, Chuncheon 24341,
Korea
| | - Adiyantara Gumilang
- Division of Bioresource Sciences, and Bioherb Research Institute, Kangwon National University, Chuncheon 24341,
Korea
| | - Yong-Hwan Lee
- Department of Agricultural Biotechnology, and Center for Fungal Genetic Resources, Seoul National University, Seoul 08826,
Korea
| | - Kyoung Su Kim
- Division of Bioresource Sciences, and Bioherb Research Institute, Kangwon National University, Chuncheon 24341,
Korea
- Corresponding author: Phone) +82-33-250-6435, FAX) +82-33-259-5558, E-mail)
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Weiner A, Orange F, Lacas‐Gervais S, Rechav K, Ghugtyal V, Bassilana M, Arkowitz RA. On‐site secretory vesicle delivery drives filamentous growth in the fungal pathogenCandida albicans. Cell Microbiol 2018; 21:e12963. [DOI: 10.1111/cmi.12963] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 10/02/2018] [Accepted: 10/04/2018] [Indexed: 12/31/2022]
Affiliation(s)
- Allon Weiner
- Université Côte d'AzurCNRS, Inserm, Institute of Biology Valrose Parc Valrose Nice France
| | | | | | - Katya Rechav
- Chemical Research SupportWeizmann Institute of Science Rehovot Israel
| | - Vikram Ghugtyal
- Université Côte d'AzurCNRS, Inserm, Institute of Biology Valrose Parc Valrose Nice France
| | - Martine Bassilana
- Université Côte d'AzurCNRS, Inserm, Institute of Biology Valrose Parc Valrose Nice France
| | - Robert A. Arkowitz
- Université Côte d'AzurCNRS, Inserm, Institute of Biology Valrose Parc Valrose Nice France
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15
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Zhang C, Luo Z, He D, Su L, Yin H, Wang G, Liu H, Rensing C, Wang Z. FgBud3, a Rho4-Interacting Guanine Nucleotide Exchange Factor, Is Involved in Polarity Growth, Cell Division and Pathogenicity of Fusarium graminearum. Front Microbiol 2018; 9:1209. [PMID: 29930543 PMCID: PMC5999796 DOI: 10.3389/fmicb.2018.01209] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 05/17/2018] [Indexed: 11/24/2022] Open
Abstract
Rho GTPases are signaling macromolecules that are associated with developmental progression and pathogenesis of Fusarium graminearum. Generally, enzymatic activities of Rho GTPases are regulated by Rho GTPase guanine nucleotide exchange factors (RhoGEFs). In this study, we identified a putative RhoGEF encoding gene (FgBUD3) in F. graminearum database and proceeded further by using a functional genetic approach to generate FgBUD3 targeted gene deletion mutant. Phenotypic analysis results showed that the deletion of FgBUD3 caused severe reduction in growth of FgBUD3 mutant generated during this study. We also observed that the deletion of FgBUD3 completely abolished sexual reproduction and triggered the production of abnormal asexual spores with nearly no septum in ΔFgbud3 strain. Further results obtained from infection assays conducted during this research revealed that the FgBUD3 defective mutant lost its pathogenicity on wheat and hence, suggests FgBud3 plays an essential role in the pathogenicity of F. graminearum. Additional, results derived from yeast two-hybrid assays revealed that FgBud3 strongly interacted with FgRho4 compared to the interaction with FgRho2, FgRho3, and FgCdc42. Moreover, we found that FgBud3 interacted with both GTP-bound and GDP-bound form of FgRho4. From these results, we subsequently concluded that, the Rho4-interacting GEF protein FgBud3 crucially promotes vegetative growth, asexual and sexual development, cell division and pathogenicity in F. graminearum.
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Affiliation(s)
- Chengkang Zhang
- Institute of Environmental Microbiology, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, China.,College of Life Science, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Zenghong Luo
- College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Dongdong He
- Institute of Environmental Microbiology, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Li Su
- College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Hui Yin
- College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Guo Wang
- Institute of Environmental Microbiology, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Hong Liu
- Institute of Environmental Microbiology, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Christopher Rensing
- Institute of Environmental Microbiology, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, China.,J. Craig Venter Institute, La Jolla, CA, United States
| | - Zonghua Wang
- College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China
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16
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da Cruz Cabral L, Delgado J, Andrade MJ, Rodríguez M, Rodríguez A. Detection of changes in mould cell wall stress-related gene expression by a novel reverse transcription real-time PCR method. Int J Food Microbiol 2018; 275:17-23. [PMID: 29604490 DOI: 10.1016/j.ijfoodmicro.2018.03.020] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 03/12/2018] [Accepted: 03/23/2018] [Indexed: 11/19/2022]
Abstract
The cell wall integrity (CWI) pathway is activated in response to cell wall stresses due to different food-related environments. Rho1 is one of the main regulators within such pathway. The objective of this work was to design an easy-to-use RT-qPCR technique for the evaluation of the Rho1 gene expression useful to measure responses to the presence of cell wall stressors such as the antifungal protein PgAFP. Two primer pairs were designed from published conserved regions. Their specificity initially was determined by in silico analysis for several fungal species. After optimising the qPCR, the primer pair Rho1-F1/R2 was selected due to the lowest Cq values obtained and its specificity. The qPCR method showed efficiencies between 97.5% and 100.5%. Applicability of the designed qPCR method was evaluated in the presence of the stressor PgAFP. The PgAFP-resistant Penicillium polonicum and the PgAFP-sensitive Aspergillus flavus showed Rho1 gene over- and under- expression, respectively, indicating that the CWI pathway is activated in the former species but not activated in the latter one in response to the stress caused by PgAFP. This novel qPCR methodology able to detect changes in CWI-related gene expression in filamentous fungi will be useful in future studies to evaluate physiological mould responses to different food environmental challenges.
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Affiliation(s)
- Lucía da Cruz Cabral
- Food Hygiene and Safety, Meat and Meat Products Research Institute, Faculty of Veterinary Science, University of Extremadura, Avda. de las Ciencias, s/n, 10003 Cáceres, Spain
| | - Josué Delgado
- Food Hygiene and Safety, Meat and Meat Products Research Institute, Faculty of Veterinary Science, University of Extremadura, Avda. de las Ciencias, s/n, 10003 Cáceres, Spain
| | - María J Andrade
- Food Hygiene and Safety, Meat and Meat Products Research Institute, Faculty of Veterinary Science, University of Extremadura, Avda. de las Ciencias, s/n, 10003 Cáceres, Spain
| | - Mar Rodríguez
- Food Hygiene and Safety, Meat and Meat Products Research Institute, Faculty of Veterinary Science, University of Extremadura, Avda. de las Ciencias, s/n, 10003 Cáceres, Spain
| | - Alicia Rodríguez
- Food Hygiene and Safety, Meat and Meat Products Research Institute, Faculty of Veterinary Science, University of Extremadura, Avda. de las Ciencias, s/n, 10003 Cáceres, Spain.
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17
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Liu R, Zhang X, Ren A, Shi DK, Shi L, Zhu J, Yu HS, Zhao MW. Heat stress-induced reactive oxygen species participate in the regulation of HSP expression, hyphal branching and ganoderic acid biosynthesis in Ganoderma lucidum. Microbiol Res 2018; 209:43-54. [PMID: 29580621 DOI: 10.1016/j.micres.2018.02.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 01/30/2018] [Accepted: 02/17/2018] [Indexed: 11/28/2022]
Abstract
Heat stress (HS) is an important environmental factor that affects the growth and metabolism of edible fungi, but the molecular mechanism of the heat stress response (HSR) remains unclear. We previously reported that HS treatment increased the length between two hyphal branches and induced the accumulation of ganoderic acid biosynthesis and the gene expression of heat shock proteins (HSPs) in Ganoderma lucidum. In this study, we found that HS induced a significant increase in the cytosolic ROS concentration, and exogenously added ROS scavengers NAC, VC and NADPH oxidase (Nox) inhibitor DPI reduce the cytosolic ROS accumulation in G. lucidum. In addition, the phenomena of the increased gene expression and increased length between the two hyphal branches and the accumulation of GA biosynthesis induced by HS were mitigated. Furthermore, we investigated the effects of HS on Nox-silenced strains (NoxABi-10, NoxABi-11 and NoxRi-4, NoxRi-7) and found that the level of ROS concentration was lower than that in wild-type (WT) strains treated with HS. Additionally, Nox silenced strains reduced the HS-induced increase in HSP expression, the length between two hyphal branches and GA biosynthesis compared with the WT strain. These data indicate that HS-induced ROS participate in the regulation of HSP expression, hyphal branching and ganoderic acid biosynthesis in G. lucidum. In addition, these findings identified potential pathways linking ROS networks to HSR, physiological and metabolic processes in fungi and provide a valuable reference for studying the role of ROS in HSR, mycelium growth and secondary metabolites.
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Affiliation(s)
- Rui Liu
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, Jiangsu, People's Republic of China
| | - Xue Zhang
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, Jiangsu, People's Republic of China
| | - Ang Ren
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, Jiangsu, People's Republic of China
| | - Deng-Ke Shi
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, Jiangsu, People's Republic of China
| | - Liang Shi
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, Jiangsu, People's Republic of China
| | - Jing Zhu
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, Jiangsu, People's Republic of China
| | - Han-Shou Yu
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, Jiangsu, People's Republic of China
| | - Ming-Wen Zhao
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, Jiangsu, People's Republic of China.
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18
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Abstract
Filamentous fungi have proven to be a better-suited model system than unicellular yeasts in analyses of cellular processes such as polarized growth, exocytosis, endocytosis, and cytoskeleton-based organelle traffic. For example, the filamentous fungus
Neurospora crassa develops a variety of cellular forms. Studying the molecular basis of these forms has led to a better, yet incipient, understanding of polarized growth. Polarity factors as well as Rho GTPases, septins, and a localized delivery of vesicles are the central elements described so far that participate in the shift from isotropic to polarized growth. The growth of the cell wall by apical biosynthesis and remodeling of polysaccharide components is a key process in hyphal morphogenesis. The coordinated action of motor proteins and Rab GTPases mediates the vesicular journey along the hyphae toward the apex, where the exocyst mediates vesicle fusion with the plasma membrane. Cytoplasmic microtubules and actin microfilaments serve as tracks for the transport of vesicular carriers as well as organelles in the tubular cell, contributing to polarization. In addition to exocytosis, endocytosis is required to set and maintain the apical polarity of the cell. Here, we summarize some of the most recent breakthroughs in hyphal morphogenesis and apical growth in
N. crassa and the emerging questions that we believe should be addressed.
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Affiliation(s)
- Meritxell Riquelme
- Department of Microbiology, Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE), Ensenada, Baja California, 22860, Mexico
| | - Leonora Martínez-Núñez
- Department of Microbiology, Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE), Ensenada, Baja California, 22860, Mexico
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19
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Xu X, Wang Y, Tian C, Liang Y. The Colletotrichum gloeosporioides RhoB regulates cAMP and stress response pathways and is required for pathogenesis. Fungal Genet Biol 2016; 96:12-24. [PMID: 27670809 DOI: 10.1016/j.fgb.2016.09.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2016] [Revised: 09/16/2016] [Accepted: 09/22/2016] [Indexed: 12/26/2022]
Abstract
Rho GTPases regulate morphology and multiple cellular functions such as asexual development, polarity establishment, and differentiation in fungi. To determine the roles of CgRhoB, a Rho GTPase protein, here we characterized CgRhoB in the poplar anthracnose fungus Colletotrichum gloeosporioides. First of all, we determined that conidial germination was inhibited and intracellular cyclic AMP (cAMP) level was increased in the CgRhoB deletion mutants. Loss of CgRhoB resulted in shorter germ tubes and enhanced appressoria formation after germination on the hydrophobic surface. Exogenous addition of cAMP to the wild type generated the similar phenotypes of ΔCgRhoB inoculated in CM liquid. Furthermore, deletion of CgRhoB had discernible effect upon the sensitivity of C. gloeosporioides to cell wall perturbing agents and altered the distribution of chitin on the cell wall. H2O2 sensitivity assay showed the hypersensitive effect on the oxidative stress, and transcriptional analysis revealed that transcription of genes involved in peroxidase activities was altered in the mutants. Finally, virulence assay revealed that CgRhoB was required for pathogenicity. Taken together, our results showed that CgRhoB was associated with appressoria formation and pathogenicity, and affected cAMP level and stress pathways.
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Affiliation(s)
- Xin Xu
- The Key Laboratory for Silviculture and Conservation of Ministry of Education, College of Forestry, Beijing Forestry University, Beijing, China
| | - Yonglin Wang
- The Key Laboratory for Silviculture and Conservation of Ministry of Education, College of Forestry, Beijing Forestry University, Beijing, China
| | - Chengming Tian
- The Key Laboratory for Silviculture and Conservation of Ministry of Education, College of Forestry, Beijing Forestry University, Beijing, China
| | - Yingmei Liang
- Museum of Beijing Forestry University, Beijing Forestry University, Beijing, China.
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20
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Dichtl K, Samantaray S, Wagener J. Cell wall integrity signalling in human pathogenic fungi. Cell Microbiol 2016; 18:1228-38. [DOI: 10.1111/cmi.12612] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Revised: 04/19/2016] [Accepted: 05/03/2016] [Indexed: 12/21/2022]
Affiliation(s)
- Karl Dichtl
- Max von Pettenkofer-Institut für Hygiene und Medizinische Mikrobiologie; Ludwig-Maximilians-Universität München; 80336 Munich Germany
| | - Sweta Samantaray
- Max von Pettenkofer-Institut für Hygiene und Medizinische Mikrobiologie; Ludwig-Maximilians-Universität München; 80336 Munich Germany
- Institute of Microbiology and Infection, School of Biosciences; University of Birmingham; Birmingham UK
| | - Johannes Wagener
- Max von Pettenkofer-Institut für Hygiene und Medizinische Mikrobiologie; Ludwig-Maximilians-Universität München; 80336 Munich Germany
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21
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Aranda-Martinez A, Lopez-Moya F, Lopez-Llorca LV. Cell wall composition plays a key role on sensitivity of filamentous fungi to chitosan. J Basic Microbiol 2016; 56:1059-1070. [DOI: 10.1002/jobm.201500775] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Accepted: 04/11/2016] [Indexed: 11/11/2022]
Affiliation(s)
- Almudena Aranda-Martinez
- Laboratory of Plant Pathology, Department of Marine Sciences, Applied Biology, Multidisciplinary Institute for Environmental Studies Ramón Margalef; University of Alicante; Alicante Spain
| | - Federico Lopez-Moya
- Laboratory of Plant Pathology, Department of Marine Sciences, Applied Biology, Multidisciplinary Institute for Environmental Studies Ramón Margalef; University of Alicante; Alicante Spain
| | - Luis Vicente Lopez-Llorca
- Laboratory of Plant Pathology, Department of Marine Sciences, Applied Biology, Multidisciplinary Institute for Environmental Studies Ramón Margalef; University of Alicante; Alicante Spain
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22
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Martin-Urdiroz M, Deeks MJ, Horton CG, Dawe HR, Jourdain I. The Exocyst Complex in Health and Disease. Front Cell Dev Biol 2016; 4:24. [PMID: 27148529 PMCID: PMC4828438 DOI: 10.3389/fcell.2016.00024] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Accepted: 03/11/2016] [Indexed: 01/23/2023] Open
Abstract
Exocytosis involves the fusion of intracellular secretory vesicles with the plasma membrane, thereby delivering integral membrane proteins to the cell surface and releasing material into the extracellular space. Importantly, exocytosis also provides a source of lipid moieties for membrane extension. The tethering of the secretory vesicle before docking and fusion with the plasma membrane is mediated by the exocyst complex, an evolutionary conserved octameric complex of proteins. Recent findings indicate that the exocyst complex also takes part in other intra-cellular processes besides secretion. These various functions seem to converge toward defining a direction of membrane growth in a range of systems from fungi to plants and from neurons to cilia. In this review we summarize the current knowledge of exocyst function in cell polarity, signaling and cell-cell communication and discuss implications for plant and animal health and disease.
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Affiliation(s)
| | - Michael J Deeks
- Biosciences, College of Life and Environmental Sciences, University of Exeter Exeter, UK
| | - Connor G Horton
- Biosciences, College of Life and Environmental Sciences, University of Exeter Exeter, UK
| | - Helen R Dawe
- Biosciences, College of Life and Environmental Sciences, University of Exeter Exeter, UK
| | - Isabelle Jourdain
- Biosciences, College of Life and Environmental Sciences, University of Exeter Exeter, UK
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23
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Mendes NS, Silva PM, Silva-Rocha R, Martinez-Rossi NM, Rossi A. Pre-mRNA splicing is modulated by antifungal drugs in the filamentous fungus Neurospora crassa. FEBS Open Bio 2016; 6:358-68. [PMID: 27239448 PMCID: PMC4821360 DOI: 10.1002/2211-5463.12047] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2015] [Revised: 02/10/2016] [Accepted: 02/15/2016] [Indexed: 11/17/2022] Open
Abstract
For this study, we sought to identify pre‐mRNA processing events modulated by changes in extracellular pH, inorganic phosphate, and antifungal drugs. We examined genes with at least four putative introns whose transcriptional level responded to these effectors. We showed that the intron retention levels of genes encoding asparagine synthetase 2, C6‐zinc finger regulator (fluffy), and a farnesyltransferase respond to amphotericin B, ketoconazole, and other effectors. In general, the assayed antifungals promoted the disruption of the structural domains of these proteins probably leading to their inactivation, which emphasize the complexity of the metabolic modulation exerted by antifungal signaling.
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Affiliation(s)
- Niege S Mendes
- Department of Genetics Ribeirão Preto Medical School University of São Paulo Ribeirão Preto SP Brazil
| | - Patricia M Silva
- Department of Genetics Ribeirão Preto Medical School University of São Paulo Ribeirão Preto SP Brazil
| | - Rafael Silva-Rocha
- Department of Molecular and Cellular Biology Ribeirão Preto Medical School University of São Paulo Ribeirão Preto SP Brazil
| | - Nilce M Martinez-Rossi
- Department of Genetics Ribeirão Preto Medical School University of São Paulo Ribeirão Preto SP Brazil
| | - Antonio Rossi
- Department of Genetics Ribeirão Preto Medical School University of São Paulo Ribeirão Preto SP Brazil
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24
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Live imaging of β-1,3-glucan synthase FKS-1 in Neurospora crassa hyphae. Fungal Genet Biol 2015; 82:104-7. [DOI: 10.1016/j.fgb.2015.07.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Revised: 07/01/2015] [Accepted: 07/02/2015] [Indexed: 11/16/2022]
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25
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Arkowitz RA, Bassilana M. Regulation of hyphal morphogenesis by Ras and Rho small GTPases. FUNGAL BIOL REV 2015. [DOI: 10.1016/j.fbr.2015.02.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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26
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Dettmann A, Heilig Y, Valerius O, Ludwig S, Seiler S. Fungal communication requires the MAK-2 pathway elements STE-20 and RAS-2, the NRC-1 adapter STE-50 and the MAP kinase scaffold HAM-5. PLoS Genet 2014; 10:e1004762. [PMID: 25411845 PMCID: PMC4239118 DOI: 10.1371/journal.pgen.1004762] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Accepted: 09/18/2014] [Indexed: 11/30/2022] Open
Abstract
Intercellular communication is critical for the survival of unicellular organisms as well as for the development and function of multicellular tissues. Cell-to-cell signaling is also required to develop the interconnected mycelial network characteristic of filamentous fungi and is a prerequisite for symbiotic and pathogenic host colonization achieved by molds. Somatic cell–cell communication and subsequent cell fusion is governed by the MAK-2 mitogen activated protein kinase (MAPK) cascade in the filamentous ascomycete model Neurospora crassa, yet the composition and mode of regulation of the MAK-2 pathway are currently unclear. In order to identify additional components involved in MAK-2 signaling we performed affinity purification experiments coupled to mass spectrometry with strains expressing functional GFP-fusion proteins of the MAPK cascade. This approach identified STE-50 as a regulatory subunit of the Ste11p homolog NRC-1 and HAM-5 as cell-communication-specific scaffold protein of the MAPK cascade. Moreover, we defined a network of proteins consisting of two Ste20-related kinases, the small GTPase RAS-2 and the adenylate cyclase capping protein CAP-1 that function upstream of the MAK-2 pathway and whose signals converge on the NRC-1/STE-50 MAP3K complex and the HAM-5 scaffold. Finally, our data suggest an involvement of the striatin interacting phosphatase and kinase (STRIPAK) complex, the casein kinase 2 heterodimer, the phospholipid flippase modulators YPK-1 and NRC-2 and motor protein-dependent vesicle trafficking in the regulation of MAK-2 pathway activity and function. Taken together, these data will have significant implications for our mechanistic understanding of MAPK signaling and for homotypic cell–cell communication in fungi and higher eukaryotes. Appropriate cellular responses to external stimuli depend on the highly orchestrated activity of interconnected signaling cascades. One crucial level of control arises from the formation of discrete complexes through scaffold proteins that bind multiple components of a given pathway. Central for our understanding of these signaling platforms is the archetypical MAP kinase scaffold Ste5p, a protein that is restricted to budding yeast and close relatives. We identified HAM-5, a protein highly conserved in filamentous ascomycete fungi, as cell–cell communication-specific scaffold protein of the Neurospora crassa MAK-2 cascade (homologous to the budding yeast pheromone pathway). We also describe a network of upstream acting proteins, consisting of two Ste20-related kinases, the small G-protein RAS-2 and the adenylate cyclase capping protein CAP-1, whose signals converge on HAM-5. Our work has implications for the mechanistic understanding of MAP kinase scaffold proteins and their function during intercellular communication in eukaryotic microbes as well as higher eukaryotes.
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Affiliation(s)
- Anne Dettmann
- Institute for Biology II – Molecular Plant Physiology, Albert-Ludwigs University Freiburg, Freiburg, Germany
| | - Yvonne Heilig
- Institute for Biology II – Molecular Plant Physiology, Albert-Ludwigs University Freiburg, Freiburg, Germany
| | - Oliver Valerius
- Institute for Microbiology and Genetics, University of Goettingen, Goettingen, Germany
| | - Sarah Ludwig
- Institute for Biology II – Molecular Plant Physiology, Albert-Ludwigs University Freiburg, Freiburg, Germany
| | - Stephan Seiler
- Institute for Biology II – Molecular Plant Physiology, Albert-Ludwigs University Freiburg, Freiburg, Germany
- Freiburg Institute for Advanced Studies (FRIAS), Albert-Ludwigs University Freiburg, Freiburg, Germany
- * E-mail:
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27
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Chinnici JL, Fu C, Caccamise LM, Arnold JW, Free SJ. Neurospora crassa female development requires the PACC and other signal transduction pathways, transcription factors, chromatin remodeling, cell-to-cell fusion, and autophagy. PLoS One 2014; 9:e110603. [PMID: 25333968 PMCID: PMC4204872 DOI: 10.1371/journal.pone.0110603] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Accepted: 09/16/2014] [Indexed: 01/01/2023] Open
Abstract
Using a screening protocol we have identified 68 genes that are required for female development in the filamentous fungus Neurospora crassa. We find that we can divide these genes into five general groups: 1) Genes encoding components of the PACC signal transduction pathway, 2) Other signal transduction pathway genes, including genes from the three N. crassa MAP kinase pathways, 3) Transcriptional factor genes, 4) Autophagy genes, and 5) Other miscellaneous genes. Complementation and RIP studies verified that these genes are needed for the formation of the female mating structure, the protoperithecium, and for the maturation of a fertilized protoperithecium into a perithecium. Perithecia grafting experiments demonstrate that the autophagy genes and the cell-to-cell fusion genes (the MAK-1 and MAK-2 pathway genes) are needed for the mobilization and movement of nutrients from an established vegetative hyphal network into the developing protoperithecium. Deletion mutants for the PACC pathway genes palA, palB, palC, palF, palH, and pacC were found to be defective in two aspects of female development. First, they were unable to initiate female development on synthetic crossing medium. However, they could form protoperithecia when grown on cellophane, on corn meal agar, or in response to the presence of nearby perithecia. Second, fertilized perithecia from PACC pathway mutants were unable to produce asci and complete female development. Protein localization experiments with a GFP-tagged PALA construct showed that PALA was localized in a peripheral punctate pattern, consistent with a signaling center associated with the ESCRT complex. The N. crassa PACC signal transduction pathway appears to be similar to the PacC/Rim101 pathway previously characterized in Aspergillus nidulans and Saccharomyces cerevisiae. In N. crassa the pathway plays a key role in regulating female development.
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Affiliation(s)
- Jennifer L. Chinnici
- Department of Biological Sciences, SUNY University at Buffalo, Buffalo, New York, United States of America
| | - Ci Fu
- Department of Biological Sciences, SUNY University at Buffalo, Buffalo, New York, United States of America
| | - Lauren M. Caccamise
- Department of Biological Sciences, SUNY University at Buffalo, Buffalo, New York, United States of America
| | - Jason W. Arnold
- Department of Biological Sciences, SUNY University at Buffalo, Buffalo, New York, United States of America
| | - Stephen J. Free
- Department of Biological Sciences, SUNY University at Buffalo, Buffalo, New York, United States of America
- * E-mail:
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Fu C, Ao J, Dettmann A, Seiler S, Free SJ. Characterization of the Neurospora crassa cell fusion proteins, HAM-6, HAM-7, HAM-8, HAM-9, HAM-10, AMPH-1 and WHI-2. PLoS One 2014; 9:e107773. [PMID: 25279949 PMCID: PMC4184795 DOI: 10.1371/journal.pone.0107773] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Accepted: 08/14/2014] [Indexed: 11/19/2022] Open
Abstract
Intercellular communication of vegetative cells and their subsequent cell fusion is vital for different aspects of growth, fitness, and differentiation of filamentous fungi. Cell fusion between germinating spores is important for early colony establishment, while hyphal fusion in the mature colony facilitates the movement of resources and organelles throughout an established colony. Approximately 50 proteins have been shown to be important for somatic cell-cell communication and fusion in the model filamentous fungus Neurospora crassa. Genetic, biochemical, and microscopic techniques were used to characterize the functions of seven previously poorly characterized cell fusion proteins. HAM-6, HAM-7 and HAM-8 share functional characteristics and are proposed to function in the same signaling network. Our data suggest that these proteins may form a sensor complex at the cell wall/plasma membrane for the MAK-1 cell wall integrity mitogen-activated protein kinase (MAPK) pathway. We also demonstrate that HAM-9, HAM-10, AMPH-1 and WHI-2 have more general functions and are required for normal growth and development. The activation status of the MAK-1 and MAK-2 MAPK pathways are altered in mutants lacking these proteins. We propose that these proteins may function to coordinate the activities of the two MAPK modules with other signaling pathways during cell fusion.
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Affiliation(s)
- Ci Fu
- Department of Biological Sciences, SUNY University at Buffalo, Buffalo, New York, United States of America
| | - Jie Ao
- Department of Biological Sciences, SUNY University at Buffalo, Buffalo, New York, United States of America
| | - Anne Dettmann
- Institute for Biology II, Albert-Ludwigs University Freiburg, Freiburg, Germany
| | - Stephan Seiler
- Institute for Biology II, Albert-Ludwigs University Freiburg, Freiburg, Germany
- Freiburg Institute for Advanced Studies (FRIAS), Albert-Ludwigs University Freiburg, Freiburg, Germany
| | - Stephen J. Free
- Department of Biological Sciences, SUNY University at Buffalo, Buffalo, New York, United States of America
- * E-mail:
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Rho GTPase-phosphatidylinositol phosphate interplay in fungal cell polarity. Biochem Soc Trans 2014; 42:206-11. [PMID: 24450653 DOI: 10.1042/bst20130226] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Rho G-proteins and phosphatidylinositol phosphates, which are important for exocytosis, endocytosis and cytoskeleton organization, are key regulators of polarized growth in a range of organisms. The aim of the present brief review is to highlight recent findings and their implications with respect to the functions and interplay between Rho G-proteins and phosphatidylinositol phosphates in highly polarized fungal filamentous growth.
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Teichert I, Steffens EK, Schnaß N, Fränzel B, Krisp C, Wolters DA, Kück U. PRO40 is a scaffold protein of the cell wall integrity pathway, linking the MAP kinase module to the upstream activator protein kinase C. PLoS Genet 2014; 10:e1004582. [PMID: 25188365 PMCID: PMC4154660 DOI: 10.1371/journal.pgen.1004582] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Accepted: 07/02/2014] [Indexed: 12/21/2022] Open
Abstract
Mitogen-activated protein kinase (MAPK) pathways are crucial signaling instruments in eukaryotes. Most ascomycetes possess three MAPK modules that are involved in key developmental processes like sexual propagation or pathogenesis. However, the regulation of these modules by adapters or scaffolds is largely unknown. Here, we studied the function of the cell wall integrity (CWI) MAPK module in the model fungus Sordaria macrospora. Using a forward genetic approach, we found that sterile mutant pro30 has a mutated mik1 gene that encodes the MAPK kinase kinase (MAPKKK) of the proposed CWI pathway. We generated single deletion mutants lacking MAPKKK MIK1, MAPK kinase (MAPKK) MEK1, or MAPK MAK1 and found them all to be sterile, cell fusion-deficient and highly impaired in vegetative growth and cell wall stress response. By searching for MEK1 interaction partners via tandem affinity purification and mass spectrometry, we identified previously characterized developmental protein PRO40 as a MEK1 interaction partner. Although fungal PRO40 homologs have been implicated in diverse developmental processes, their molecular function is currently unknown. Extensive affinity purification, mass spectrometry, and yeast two-hybrid experiments showed that PRO40 is able to bind MIK1, MEK1, and the upstream activator protein kinase C (PKC1). We further found that the PRO40 N-terminal disordered region and the central region encompassing a WW interaction domain are sufficient to govern interaction with MEK1. Most importantly, time- and stress-dependent phosphorylation studies showed that PRO40 is required for MAK1 activity. The sum of our results implies that PRO40 is a scaffold protein for the CWI pathway, linking the MAPK module to the upstream activator PKC1. Our data provide important insights into the mechanistic role of a protein that has been implicated in sexual and asexual development, cell fusion, symbiosis, and pathogenicity in different fungal systems. The specific response to environmental cues is crucial for cell differentiation and is often mediated by highly conserved eukaryotic MAP kinase (MAPK) pathways. How these pathways react specifically to huge numbers of different cues is still unclear, and current literature about adapter and scaffolding proteins remains scarce. However, gaining fundamental insight into molecular signaling determinants is pivotal for combating diseases with impaired signal transduction processes, such as Alzheimer's disease or cancer. Importantly, signal transduction can easily be studied in lower eukaryotes like filamentous fungi that are readily genetically tractable. The fungus Sordaria macrospora has a long history as an ideal model system for cell differentiation, and we show here that the proposed cell wall integrity (CWI) MAPK module of this fungus controls differentiation of sexual fruiting bodies, cell fusion, polar growth and cell wall stress response. We further discovered that developmental protein PRO40 binds the MAPK kinase kinase (MAPKKK), the MAPK kinase (MAPKK) and upstream activator protein kinase C (PKC1) of the CWI pathway and is required for MAK1 activity, thereby providing evidence that PRO40 is a scaffold protein. Collectively, our findings reveal a molecular role for a protein implicated in development, cell fusion, symbiosis, and pathogenicity in different fungi.
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Affiliation(s)
- Ines Teichert
- Department for General and Molecular Botany, Ruhr-University Bochum, Bochum, Germany
| | | | - Nicole Schnaß
- Department for General and Molecular Botany, Ruhr-University Bochum, Bochum, Germany
| | - Benjamin Fränzel
- Department of Analytical Chemistry, Ruhr-University Bochum, Bochum, Germany
| | - Christoph Krisp
- Department of Analytical Chemistry, Ruhr-University Bochum, Bochum, Germany
| | - Dirk A. Wolters
- Department of Analytical Chemistry, Ruhr-University Bochum, Bochum, Germany
| | - Ulrich Kück
- Department for General and Molecular Botany, Ruhr-University Bochum, Bochum, Germany
- * E-mail:
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Nordmann D, Lickfeld M, Warnsmann V, Wiechert J, Jendretzki A, Schmitz HP. The small GTP-binding proteins AgRho2 and AgRho5 regulate tip-branching, maintenance of the growth axis and actin-ring-integrity in the filamentous fungus Ashbya gossypii. PLoS One 2014; 9:e106236. [PMID: 25171205 PMCID: PMC4149541 DOI: 10.1371/journal.pone.0106236] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Accepted: 08/04/2014] [Indexed: 12/02/2022] Open
Abstract
GTPases of the Rho family are important molecular switches that regulate many basic cellular processes. The function of the Rho2 and Rho5 proteins from Saccharomyces cerevisiae and of their homologs in other species is poorly understood. Here, we report on the analysis of the AgRho2 and AgRho5 proteins of the filamentous fungus Ashbya gossypii. In contrast to S. cerevisiae mutants of both encoding genes displayed a strong morphological phenotype. The Agrho2 mutants showed defects in tip-branching, while Agrho5 mutants had a significantly decreased growth rate and failed to maintain their growth axis. In addition, the Agrho5 mutants had highly defective actin rings at septation sites. We also found that a deletion mutant of a putative GDP-GTP-exchange factor (GEF) that was homologous to a Rac-GEF from other species phenocopied the Agrho5 mutant, suggesting that both proteins act in the same pathway, but the AgRho5 protein has acquired functions that are fulfilled by Rac-proteins in other species.
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Affiliation(s)
- Doris Nordmann
- Department of Genetics, University of Osnabrück, Osnabrück, Germany
| | - Manuela Lickfeld
- Department of Genetics, University of Osnabrück, Osnabrück, Germany
| | - Verena Warnsmann
- Department of Genetics, University of Osnabrück, Osnabrück, Germany
| | - Johanna Wiechert
- Department of Genetics, University of Osnabrück, Osnabrück, Germany
| | - Arne Jendretzki
- Department of Genetics, University of Osnabrück, Osnabrück, Germany
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Riquelme M, Sánchez-León E. The Spitzenkörper: a choreographer of fungal growth and morphogenesis. Curr Opin Microbiol 2014; 20:27-33. [DOI: 10.1016/j.mib.2014.04.003] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Revised: 04/24/2014] [Accepted: 04/25/2014] [Indexed: 01/07/2023]
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Delgado-Álvarez DL, Bartnicki-García S, Seiler S, Mouriño-Pérez RR. Septum development in Neurospora crassa: the septal actomyosin tangle. PLoS One 2014; 9:e96744. [PMID: 24800890 PMCID: PMC4011870 DOI: 10.1371/journal.pone.0096744] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Accepted: 04/10/2014] [Indexed: 12/05/2022] Open
Abstract
Septum formation in Neurospora crassa was studied by fluorescent tagging of actin, myosin, tropomyosin, formin, fimbrin, BUD-4, and CHS-1. In chronological order, we recognized three septum development stages: 1) septal actomyosin tangle (SAT) assembly, 2) contractile actomyosin ring (CAR) formation, 3) CAR constriction together with plasma membrane ingrowth and cell wall construction. Septation began with the assembly of a conspicuous tangle of cortical actin cables (SAT) in the septation site >5 min before plasma membrane ingrowth. Tropomyosin and myosin were detected as components of the SAT from the outset. The SAT gradually condensed to form a proto-CAR that preceded CAR formation. During septum development, the contractile actomyosin ring remained associated with the advancing edge of the septum. Formin and BUD-4 were recruited during the transition from SAT to CAR and CHS-1 appeared two min before CAR constriction. Actin patches containing fimbrin were observed surrounding the ingrowing septum, an indication of endocytic activity. Although the trigger of SAT assembly remains unclear, the regularity of septation both in space and time gives us reason to believe that the initiation of the septation process is integrated with the mechanisms that control both the cell cycle and the overall growth of hyphae, despite the asynchronous nature of mitosis in N. crassa.
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Affiliation(s)
- Diego Luis Delgado-Álvarez
- Departamento de Microbiología, Centro de Educación Científica y de Educación Superior de Ensenada, Ensenada, B. C. México
| | - Salomón Bartnicki-García
- Departamento de Microbiología, Centro de Educación Científica y de Educación Superior de Ensenada, Ensenada, B. C. México
| | - Stephan Seiler
- Institute for Biology II – Molecular Plant Physiology, Albert-Ludwigs University Freiburg, Freiburg, Germany
- Freiburg Institute for Advanced Studies (FRIAS), Albert-Ludwigs University Freiburg, Freiburg, Germany
| | - Rosa Reyna Mouriño-Pérez
- Departamento de Microbiología, Centro de Educación Científica y de Educación Superior de Ensenada, Ensenada, B. C. México
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Proper actin ring formation and septum constriction requires coordinated regulation of SIN and MOR pathways through the germinal centre kinase MST-1. PLoS Genet 2014; 10:e1004306. [PMID: 24762679 PMCID: PMC3998894 DOI: 10.1371/journal.pgen.1004306] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Accepted: 02/25/2014] [Indexed: 12/17/2022] Open
Abstract
Nuclear DBF2p-related (NDR) kinases constitute a functionally conserved protein family of eukaryotic regulators that control cell division and polarity. In fungi, they function as effector kinases of the morphogenesis (MOR) and septation initiation (SIN) networks and are activated by pathway-specific germinal centre (GC) kinases. We characterized a third GC kinase, MST-1, that connects both kinase cascades. Genetic and biochemical interactions with SIN components and life cell imaging identify MST-1 as SIN-associated kinase that functions in parallel with the GC kinase SID-1 to activate the SIN-effector kinase DBF-2. SID-1 and MST-1 are both regulated by the upstream SIN kinase CDC-7, yet in an opposite manner. Aberrant cortical actomyosin rings are formed in Δmst-1, which resulted in mis-positioned septa and irregular spirals, indicating that MST-1-dependent regulation of the SIN is required for proper formation and constriction of the septal actomyosin ring. However, MST-1 also interacts with several components of the MOR network and modulates MOR activity at multiple levels. MST-1 functions as promiscuous enzyme and also activates the MOR effector kinase COT-1 through hydrophobic motif phosphorylation. In addition, MST-1 physically interacts with the MOR kinase POD-6, and dimerization of both proteins inactivates the GC kinase hetero-complex. These data specify an antagonistic relationship between the SIN and MOR during septum formation in the filamentous ascomycete model Neurospora crassa that is, at least in part, coordinated through the GC kinase MST-1. The similarity of the SIN and MOR pathways to the animal Hippo and Ndr pathways, respectively, suggests that intensive cross-communication between distinct NDR kinase modules may also be relevant for the homologous NDR kinases of higher eukaryotes. Cytokinesis is a fundamental cellular process essential for cell proliferation of uni- and multicellular organisms. The molecular pathways that regulate cytokinesis are highly complex and involve a large number of components that form elaborate interactive networks. The fungal septation initiation network (SIN) functions as tripartite kinase cascade that connects cell cycle progression with the control of cell division. Mis-regulation of the homologous Hippo pathway in animals results in excessive proliferation and formation of tumors, underscoring the conservation and importance of these kinase networks. A second morphogenesis (MOR) pathway involves homologous components and is controlling cell polarity in fungi and higher eukaryotes. Here we show that the promiscuous functioning Ste20-related kinase MST-1 has a dual role in regulating SIN and MOR network function. Moreover, SIN and MOR coordination through MST-1 can be achieved in an enzyme-independent manner through hetero-dimerization of germinal centre kinases, providing an additional level for activity regulation of signaling networks that is not dependent on phosphate transfer. Given the functional conservation of NDR kinase signaling modules and their regulation, our work may define general mechanisms by which NDR kinase pathway are coordinated in fungi and higher eukaryotes.
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Riquelme M, Bredeweg EL, Callejas-Negrete O, Roberson RW, Ludwig S, Beltrán-Aguilar A, Seiler S, Novick P, Freitag M. The Neurospora crassa exocyst complex tethers Spitzenkörper vesicles to the apical plasma membrane during polarized growth. Mol Biol Cell 2014; 25:1312-26. [PMID: 24523289 PMCID: PMC3982996 DOI: 10.1091/mbc.e13-06-0299] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Fungal hyphae are among the most highly polarized cells. Hyphal polarized growth is supported by tip-directed transport of secretory vesicles, which accumulate temporarily in a stratified manner in an apical vesicle cluster, the Spitzenkörper. The exocyst complex is required for tethering of secretory vesicles to the apical plasma membrane. We determined that the presence of an octameric exocyst complex is required for the formation of a functional Spitzenkörper and maintenance of regular hyphal growth in Neurospora crassa. Two distinct localization patterns of exocyst subunits at the hyphal tip suggest the dynamic formation of two assemblies. The EXO-70/EXO-84 subunits are found at the peripheral part of the Spitzenkörper, which partially coincides with the outer macrovesicular layer, whereas exocyst components SEC-5, -6, -8, and -15 form a delimited crescent at the apical plasma membrane. Localization of SEC-6 and EXO-70 to the plasma membrane and the Spitzenkörper, respectively, depends on actin and microtubule cytoskeletons. The apical region of exocyst-mediated vesicle fusion, elucidated by the plasma membrane-associated exocyst subunits, indicates the presence of an exocytotic gradient with a tip-high maximum that dissipates gradually toward the subapex, confirming the earlier predictions of the vesicle supply center model for hyphal morphogenesis.
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Affiliation(s)
- Meritxell Riquelme
- Department of Microbiology, Center for Scientific Research and Higher Education of Ensenada, Ensenada, BC 22860, Mexico Department of Biochemistry and Biophysics, Center for Genome Research and Biocomputing, Oregon State University, Corvallis, OR 97331 School of Life Sciences, Arizona State University, Tempe, AZ 85287 Department of Molecular Plant Physiology, Institute for Biologie II, Albert-Ludwigs University Freiburg, 79104 Freiburg, Germany Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093
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36
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Martins I, Hartmann DO, Alves PC, Planchon S, Renaut J, Leitão MC, Rebelo LP, Silva Pereira C. Proteomic alterations induced by ionic liquids in Aspergillus nidulans and Neurospora crassa. J Proteomics 2013; 94:262-78. [DOI: 10.1016/j.jprot.2013.09.015] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2013] [Revised: 09/13/2013] [Accepted: 09/27/2013] [Indexed: 02/03/2023]
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37
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Zhang C, Wang Y, Wang J, Zhai Z, Zhang L, Zheng W, Zheng W, Yu W, Zhou J, Lu G, Shim WB, Wang Z. Functional characterization of Rho family small GTPases in Fusarium graminearum. Fungal Genet Biol 2013; 61:90-9. [DOI: 10.1016/j.fgb.2013.09.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Revised: 09/06/2013] [Accepted: 09/06/2013] [Indexed: 11/28/2022]
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38
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Gras DE, Persinoti GF, Peres NT, Martinez-Rossi NM, Tahira AC, Reis EM, Prade RA, Rossi A. Transcriptional profiling of Neurospora crassa Δmak-2 reveals that mitogen-activated protein kinase MAK-2 participates in the phosphate signaling pathway. Fungal Genet Biol 2013; 60:140-9. [DOI: 10.1016/j.fgb.2013.05.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2012] [Revised: 05/01/2013] [Accepted: 05/18/2013] [Indexed: 11/16/2022]
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39
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Heilig Y, Schmitt K, Seiler S. Phospho-regulation of the Neurospora crassa septation initiation network. PLoS One 2013; 8:e79464. [PMID: 24205386 PMCID: PMC3804505 DOI: 10.1371/journal.pone.0079464] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Accepted: 09/28/2013] [Indexed: 01/04/2023] Open
Abstract
Proper cell division is essential for growth and development of uni- and multicellular organisms. The fungal septation initiation network (SIN) functions as kinase cascade that connects cell cycle progression with the initiation of cytokinesis. Miss-regulation of the homologous Hippo pathway in animals results in excessive cell proliferation and formation of tumors, underscoring the conservation of both pathways. How SIN proteins interact and transmit signals through the cascade is only beginning to be understood. Moreover, our understanding of septum formation and its regulation in filamentous fungi, which represent the vast majority of the fungal kingdom, is highly fragmentary. We determined that a tripartite kinase cascade, consisting of CDC-7, SID-1 and DBF-2, together with their regulatory subunits CDC-14 and MOB-1, is important for septum formation in the model mold Neurospora crassa. DBF-2 activity and septum formation requires auto-phosphorylation at Ser499 within the activation segment and phosphorylation of Thr671 in the hydrophobic motif by SID-1. Moreover, SID-1-stimulated DBF-2 activity is further enhanced by CDC-7, supporting a stepwise activation mechanism of the tripartite SIN kinase cascade in fungi. However, in contrast to the situation described for unicellular yeasts, the localization of the entire SIN cascade to spindle pole bodies is constitutive and cell cycle independent. Moreover, all SIN proteins except CDC-7 form cortical rings prior to septum initiation and localize to constricting septa. Thus, SIN localization and activity regulation significantly differs in unicellular versus syncytial ascomycete fungi.
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Affiliation(s)
- Yvonne Heilig
- Institute for Biology II – Molecular Plant Physiology, Albert-Ludwigs University Freiburg, Freiburg, Germany
| | - Kerstin Schmitt
- Institute for Microbiology and Genetics, University of Goettingen, Goettingen, Germany
| | - Stephan Seiler
- Institute for Biology II – Molecular Plant Physiology, Albert-Ludwigs University Freiburg, Freiburg, Germany
- Freiburg Institute for Advanced Studies (FRIAS), Albert-Ludwigs University Freiburg, Freiburg, Germany
- * E-mail:
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40
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Dettmann A, Heilig Y, Ludwig S, Schmitt K, Illgen J, Fleißner A, Valerius O, Seiler S. HAM-2 and HAM-3 are central for the assembly of the Neurospora STRIPAK complex at the nuclear envelope and regulate nuclear accumulation of the MAP kinase MAK-1 in a MAK-2-dependent manner. Mol Microbiol 2013; 90:796-812. [PMID: 24028079 DOI: 10.1111/mmi.12399] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/10/2013] [Indexed: 12/20/2022]
Abstract
Intercellular communication and somatic cell fusion are important for fungal colony establishment, multicellular differentiation and have been associated with host colonization and virulence of pathogenic species. By a combination of genetic, biochemical and live cell imaging techniques, we characterized the Neurospora crassa STRIPAK complex that is essential for self-signalling and consists of the six proteins HAM-2/STRIP, HAM-3/striatin, HAM-4/SLMAP, MOB-3/phocein, PPG-1/PP2A-C and PP2A-A. We describe that the core STRIPAK components HAM-2 and HAM-3 are central for the assembly of the complex at the nuclear envelope, while the phosphatase PPG-1 only transiently associates with this central subcomplex. Our data connect the STRIPAK complex with two MAP kinase pathways: (i) nuclear accumulation of the cell wall integrity MAP kinase MAK-1 depends on the functional integrity of the STRIPAK complex at the nuclear envelope, and (ii) phosphorylation of MOB-3 by the MAP kinase MAK-2 impacts the nuclear accumulation of MAK-1. In summary, these data support a model, in which MAK-2-dependent phosphorylation of MOB-3 is part of a MAK-1 import mechanism. Although self-communication remained intact in the absence of nuclear MAK-1 accumulation, supporting the presence of multiple mechanisms that co-ordinate robust intercellular communication, proper fruiting body morphology was dependent on the MAK-2-phosphorylated N-terminus of MOB-3.
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Affiliation(s)
- Anne Dettmann
- Institute for Biology II - Molecular Plant Physiology, Albert-Ludwigs University Freiburg, Schänzlestr. 1, 79104, Freiburg, Germany
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Corvest V, Bogliolo S, Follette P, Arkowitz RA, Bassilana M. Spatiotemporal regulation of Rho1 and Cdc42 activity duringCandida albicansfilamentous growth. Mol Microbiol 2013; 89:626-48. [DOI: 10.1111/mmi.12302] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/18/2013] [Indexed: 01/02/2023]
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42
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The plasma membrane proton pump PMA-1 is incorporated into distal parts of the hyphae independently of the Spitzenkörper in Neurospora crassa. EUKARYOTIC CELL 2013; 12:1097-105. [PMID: 23729384 DOI: 10.1128/ec.00328-12] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Most models for fungal growth have proposed a directional traffic of secretory vesicles to the hyphal apex, where they temporarily aggregate at the Spitzenkörper before they fuse with the plasma membrane (PM). The PM H(+)-translocating ATPase (PMA-1) is delivered via the classical secretory pathway (endoplasmic reticulum [ER] to Golgi) to the cell surface, where it pumps H(+) out of the cell, generating a large electrochemical gradient that supplies energy to H(+)-coupled nutrient uptake systems. To characterize the traffic and delivery of PMA-1 during hyphal elongation, we have analyzed by laser scanning confocal microscopy (LSCM) strains of Neurospora crassa expressing green fluorescent protein (GFP)-tagged versions of the protein. In conidia, PMA-1-GFP was evenly distributed at the PM. During germination and germ tube elongation, PMA-1-GFP was found all around the conidial PM and extended to the germ tube PM, but fluorescence was less intense or almost absent at the tip. Together, the data indicate that the electrochemical gradient driving apical nutrient uptake is generated from early developmental stages. In mature hyphae, PMA-1-GFP localized at the PM at distal regions (>120 μm) and in completely developed septa, but not at the tip, indicative of a distinct secretory route independent of the Spitzenkörper occurring behind the apex.
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Role of the guanine nucleotide exchange factor Rom2 in cell wall integrity maintenance of Aspergillus fumigatus. EUKARYOTIC CELL 2012; 12:288-98. [PMID: 23264643 DOI: 10.1128/ec.00246-12] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Aspergillus fumigatus is a mold and the causal agent of invasive aspergillosis, a systemic disease with high lethality. Recently, we identified and functionally characterized three stress sensors implicated in the cell wall integrity (CWI) signaling of this pathogen, namely, Wsc1, Wsc3, and MidA. Here, we functionally characterize Rom2, a guanine nucleotide exchange factor with essential function for the cell wall integrity of A. fumigatus. A conditional rom2 mutant has severe growth defects under repressive conditions and incorporates all phenotypes of the three cell wall integrity sensor mutants, e.g., the echinocandin sensitivity of the Δwsc1 mutant and the Congo red, calcofluor white, and heat sensitivity of the ΔmidA mutant. Rom2 interacts with Rho1 and shows a similar intracellular distribution focused at the hyphal tips. Our results place Rom2 between the cell surface stress sensors Wsc1, Wsc3, MidA, and Rho1 and their downstream effector mitogen-activated protein (MAP) kinase module Bck1-Mkk2-MpkA.
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Dettmann A, Illgen J, März S, Schürg T, Fleissner A, Seiler S. The NDR kinase scaffold HYM1/MO25 is essential for MAK2 map kinase signaling in Neurospora crassa. PLoS Genet 2012; 8:e1002950. [PMID: 23028357 PMCID: PMC3447951 DOI: 10.1371/journal.pgen.1002950] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Accepted: 07/30/2012] [Indexed: 12/22/2022] Open
Abstract
Cell communication is essential for eukaryotic development, but our knowledge of molecules and mechanisms required for intercellular communication is fragmentary. In particular, the connection between signal sensing and regulation of cell polarity is poorly understood. In the filamentous ascomycete Neurospora crassa, germinating spores mutually attract each other and subsequently fuse. During these tropic interactions, the two communicating cells rapidly alternate between two different physiological states, probably associated with signal delivery and response. The MAK2 MAP kinase cascade mediates cell–cell signaling. Here, we show that the conserved scaffolding protein HYM1/MO25 controls the cell shape-regulating NDR kinase module as well as the signal-receiving MAP kinase cascade. HYM1 functions as an integral part of the COT1 NDR kinase complex to regulate the interaction with its upstream kinase POD6 and thereby COT1 activity. In addition, HYM1 interacts with NRC1, MEK2, and MAK2, the three kinases of the MAK2 MAP kinase cascade, and co-localizes with MAK2 at the apex of growing cells. During cell fusion, the three kinases of the MAP kinase module as well as HYM1 are recruited to the point of cell–cell contact. hym-1 mutants phenocopy all defects observed for MAK2 pathway mutants by abolishing MAK2 activity. An NRC1-MEK2 fusion protein reconstitutes MAK2 signaling in hym-1, while constitutive activation of NRC1 and MEK2 does not. These data identify HYM1 as a novel regulator of the NRC1-MEK2-MAK2 pathway, which may coordinate NDR and MAP kinase signaling during cell polarity and intercellular communication. Intercellular communication and cellular morphogenesis are essential for eukaryotic development. Our knowledge of molecules and mechanisms associated with these processes is, however, fragmentary. In particular, the molecular connection between signal sensing and regulation of cell polarity is poorly understood. Fungal hyphae share with neurons and pollen tubes the distinction of being amongst the most highly polarized cells in biology. The robust genetic tractability of filamentous fungi provides an unparalleled opportunity to determine common principles that underlie polarized growth and its regulation through cell communication. In Neurospora crassa, germinating spores mutually attract each other, establish physical contact through polarized tropic growth, and fuse. During this process, the cells rapidly alternate between two different physiological states, probably associated with signal delivery and response. Here, we show that the conserved scaffolding protein HYM1/MO25 interacts with the polarity and cell shape-regulating NDR kinase complex as well as a MAP kinase module, which is essential for cell communication during the tropic interaction. We propose that this dual use of a common regulator in both molecular complexes may represent an intriguing mechanism of linking the perception of external cues with the polarization machinery to coordinate communication and tropic growth of interacting cells.
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Affiliation(s)
- Anne Dettmann
- Institute for Microbiology and Genetics, University of Goettingen, Goettingen, Germany
| | - Julia Illgen
- Institute for Genetics, Technische Universität Braunschweig, Braunschweig, Germany
| | - Sabine März
- Institute for Microbiology and Genetics, University of Goettingen, Goettingen, Germany
| | - Timo Schürg
- Institute for Genetics, Technische Universität Braunschweig, Braunschweig, Germany
| | - Andre Fleissner
- Institute for Genetics, Technische Universität Braunschweig, Braunschweig, Germany
| | - Stephan Seiler
- Institute for Microbiology and Genetics, University of Goettingen, Goettingen, Germany
- * E-mail:
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Maddi A, Dettman A, Fu C, Seiler S, Free SJ. WSC-1 and HAM-7 are MAK-1 MAP kinase pathway sensors required for cell wall integrity and hyphal fusion in Neurospora crassa. PLoS One 2012; 7:e42374. [PMID: 22879952 PMCID: PMC3411791 DOI: 10.1371/journal.pone.0042374] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2012] [Accepted: 07/04/2012] [Indexed: 11/18/2022] Open
Abstract
A large number of cell wall proteins are encoded in the Neurospora crassa genome. Strains carrying gene deletions of 65 predicted cell wall proteins were characterized. Deletion mutations in two of these genes (wsc-1 and ham-7) have easily identified morphological and inhibitor-based defects. Their phenotypic characterization indicates that HAM-7 and WSC-1 function during cell-to-cell hyphal fusion and in cell wall integrity maintenance, respectively. wsc-1 encodes a transmembrane protein with extensive homology to the yeast Wsc family of sensor proteins. In N. crassa, WSC-1 (and its homolog WSC-2) activates the cell wall integrity MAK-1 MAP kinase pathway. The GPI-anchored cell wall protein HAM-7 is required for cell-to-cell fusion and the sexual stages of the N. crassa life cycle. Like WSC-1, HAM-7 is required for activating MAK-1. A Δwsc-1;Δham-7 double mutant fully phenocopies mutants lacking components of the MAK-1 MAP kinase cascade. The data identify WSC-1 and HAM-7 as the major cell wall sensors that regulate two distinct MAK-1-dependent cellular activities, cell wall integrity and hyphal anastomosis, respectively.
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Affiliation(s)
- Abhiram Maddi
- Department of Biological Sciences, State University of New York, University at Buffalo, Buffalo, New York, United States of America
- Department of Periodontics and Endodontics, School of Dental Medicine, State University of New York, University at Buffalo, Buffalo, New York, United States of America
| | - Anne Dettman
- Institute for Microbiology and Genetics, Department of Molecular Microbiology and Genetics, Georg-August-University, Göttingen, Germany
| | - Ci Fu
- Department of Biological Sciences, State University of New York, University at Buffalo, Buffalo, New York, United States of America
| | - Stephan Seiler
- Institute for Microbiology and Genetics, Department of Molecular Microbiology and Genetics, Georg-August-University, Göttingen, Germany
- * E-mail: (SS); (SF)
| | - Stephen J. Free
- Department of Biological Sciences, State University of New York, University at Buffalo, Buffalo, New York, United States of America
- * E-mail: (SS); (SF)
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