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Zhang LB, Yang ZH, Yang WWJ, Guan Y. A novel fungal sensor (Ngs1) of N-acetylglucosamine (GlcNAc) mediates the fungal response to GlcNAc in the interaction between entomopathogenic Beauveria bassiana and insect host. J Invertebr Pathol 2024; 207:108206. [PMID: 39306323 DOI: 10.1016/j.jip.2024.108206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2024] [Revised: 09/10/2024] [Accepted: 09/18/2024] [Indexed: 09/27/2024]
Abstract
As N-acetylglucosamine (GlcNAc) ubiquitously exists in both insect cuticle and fungal cell walls, the GlcNAc sensor (Ngs1) potentially plays important roles in the interactions between entomopathogenic fungi and their insect hosts. However, the roles of the Ngs1 derived from the entomopathogens in response to the host's cuticle remain completely unexplored. In this study, a putative Ngs1 homolog was identified in the entomopathogenic fungus Beauveria bassiana. Deletion of Ngs1 significantly reduced virulence towards Galleria mellonella larvae either through cuticle infection (by 23%) or by bypassing the cuticle (by 44%). To investigate the role of Ngs1 in fungal virulence, an analysis of the transcriptome induced by Locusta migratoria exoskeleton was conducted, highlighting the regulatory mechanism of Ngs1 in carbohydrate metabolic process, particularly chitin metabolism and GlcNAc metabolism. Consistent with the transcriptomic data, Ngs1-deletion mutants showed reduced activities of both secreted chitinase (17% reduction) and Pr1 protease (35% reduction). Loss of Ngs1 down-regulated the transcript levels of GlcNAc-catabolism genes, resulting in a 17% decrease in fungal growth on GlcNAc-supported media. Furthermore, Ngs1 deficiency attenuated the fungal response to GlcNAc, leading to the alteration of fungal resistance to diverse stress cues. All of these changes contribute to the reduction in virulence in Ngs1-deficient B. bassiana. These findings support that Ngs1 plays a critical role in responding to insect-derived GlcNAc, affecting the production of cuticle-degrading enzymes to penetrate insect epidermis, GlcNAc-induced changes of stress resistance, and contribute to the fungal virulence against insects.
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Affiliation(s)
- Long-Bin Zhang
- College of Biological Science and Engineering, Fuzhou University, Fujian, China; The Key Laboratory of Marine Enzyme Engineering of Fujian Province, Fuzhou University, Fujian, China.
| | - Zhi-Hao Yang
- College of Biological Science and Engineering, Fuzhou University, Fujian, China; The Key Laboratory of Marine Enzyme Engineering of Fujian Province, Fuzhou University, Fujian, China
| | - Wu-Wei-Jie Yang
- College of Biological Science and Engineering, Fuzhou University, Fujian, China; The Key Laboratory of Marine Enzyme Engineering of Fujian Province, Fuzhou University, Fujian, China
| | - Yi Guan
- College of Biological Science and Engineering, Fuzhou University, Fujian, China; The Key Laboratory of Marine Enzyme Engineering of Fujian Province, Fuzhou University, Fujian, China.
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Williams C, Carnahan BR, Hyland SN, Grimes CL. Bioorthogonal labeling of chitin in pathogenic Candida species reveals biochemical mechanisms of hyphal growth and homeostasis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.27.609898. [PMID: 39253419 PMCID: PMC11383299 DOI: 10.1101/2024.08.27.609898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/11/2024]
Abstract
Pathogenic fungi rely on the cell wall component, chitin, for critical structural and immunological functions. Here a chitin labeling method to visualize the hyphal pathogenic response was developed. The data show that filamentous fungi, Candida albicans , transport N -acetylglucosamine (NAG) bio-orthogonal probes and incorporate them into the cell wall, indicating the probes utility for in vivo study of the morphological, pathogenic switch. As yeast reside in complex microenvironments, The data show that the opportunistic microbe C. albicans , has developed processes to utilize surrounding bacterial cell wall fragments to initiate the morphogenic switch. The probes are utilized for visualization of growth patterns of pathogenic fungi, providing insights into novel mechanisms for the development of antifungals. Remodeling chitin in fungi using NAG derivatives will advance yeast pathogenic studies.
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3
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Zhang LB, Yang WWJ, Yang ZH, Guan Y. N-acetylglucosamine kinase (BbHxk1) has pleiotropic effects on vegetative growth, cell wall integrity, morphological transition, cuticle infection, and metabolic modulation in the biological pesticide Beauveria bassiana. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2024; 203:106015. [PMID: 39084806 DOI: 10.1016/j.pestbp.2024.106015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2024] [Revised: 06/20/2024] [Accepted: 07/02/2024] [Indexed: 08/02/2024]
Abstract
Beauveria bassiana is a popular and eco-friendly biopesticide. During its pathogen-pest interaction, both N-acetylglucosamine (GlcNAc) catabolism and anabolism are crucial for nutrient supply and cell-wall construction. The initiation of GlcNAc metabolism relies on the catalysis of GlcNAc kinase, which has been extensively studied in the human pathogen Candida albicans. However, the physiological function of GlcNAc kinase remains poorly understood in entomopathogenic fungi. In the present study, a GlcNAc kinase homolog was identified and designated as BbHxk1 in B. bassiana. Deletion of BbHxk1 resulted in viable but reduced vegetative growth on various carbon sources. ΔBbHxk1 mutants displayed severe defects in cell wall integrity, making them more susceptible to cell wall stress cues. Furthermore, the absence of BbHxk1 resulted in an increase in conidial yield and blastospore production, and a faster rate of germination and filamentation, potentially attributed to higher intracellular ATP levels. BbHxk1 deficiency led to a reduction in the activities of cuticle-degrading enzymes, which might contribute to the attenuated pathogenicity specifically through cuticle penetration rather than hemocoel infection towards Galleria mellonella larvae. Being different from C. albicans Hxk1, which facultatively acts as a catalyzing enzyme and transcriptional regulator, BbHxk1 primarily acts as a catalyzing enzyme and metabolic regulator. The altered metabolomic profiling correlated with the phenotypic defects in ΔBbHxk1 mutants, further implicating a potential metabolism-dependent mechanism of BbHxk1 in mediating physiologies of B. bassiana. These findings not only unveil a novel role for GlcNAc kinase in B. bassiana, but also provide a solid theoretical basis to guide metabolic reprogramming in order to maintain or even enhance the efficiency of fungi for practical applications.
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Affiliation(s)
- Long-Bin Zhang
- College of Biological Science and Engineering, Fuzhou University, Fujian, China; The Key Laboratory of Marine Enzyme Engineering of Fujian Province, Fuzhou University, Fujian, China.
| | - Wu-Wei-Jie Yang
- College of Biological Science and Engineering, Fuzhou University, Fujian, China; The Key Laboratory of Marine Enzyme Engineering of Fujian Province, Fuzhou University, Fujian, China
| | - Zhi-Hao Yang
- College of Biological Science and Engineering, Fuzhou University, Fujian, China; The Key Laboratory of Marine Enzyme Engineering of Fujian Province, Fuzhou University, Fujian, China
| | - Yi Guan
- College of Biological Science and Engineering, Fuzhou University, Fujian, China; The Key Laboratory of Marine Enzyme Engineering of Fujian Province, Fuzhou University, Fujian, China.
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4
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Nishikawa A, Karita S, Umekawa M. Ngk1 kinase-mediated N-acetylglucosamine metabolism promotes UDP-GlcNAc biosynthesis in Saccharomyces cerevisiae. FEBS Lett 2024; 598:1644-1654. [PMID: 38622055 DOI: 10.1002/1873-3468.14881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 02/07/2024] [Accepted: 03/25/2024] [Indexed: 04/17/2024]
Abstract
N-acetylglucosamine (GlcNAc) is an important structural component of the cell wall chitin, N-glycans, glycolipids, and GPI-anchors in eukaryotes. GlcNAc kinase phosphorylates GlcNAc into GlcNAc-6-phosphate, a precursor of uridine diphosphate N-acetylglucosamine (UDP-GlcNAc) that serves as a substrate for glycan synthesis. Although GlcNAc kinase is found widely in organisms ranging from microorganisms to mammals, it has never been found in the model yeast Saccharomyces cerevisiae. Here, we demonstrate the presence of GlcNAc metabolism for UDP-GlcNAc biosynthesis in S. cerevisiae through Ngk1, a GlcNAc kinase we discovered previously. The overexpression or deletion of Ngk1 in the presence of GlcNAc affected the amount of both UDP-GlcNAc and chitin, suggesting that GlcNAc metabolism via Ngk1 promotes UDP-GlcNAc synthesis. Our data suggest that the Ngk1-mediated GlcNAc metabolism compensates for the hexosamine pathway, a known pathway for UDP-GlcNAc synthesis.
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Affiliation(s)
| | - Shuichi Karita
- Graduate School of Bioresources, Mie University, Tsu, Japan
| | - Midori Umekawa
- Graduate School of Bioresources, Mie University, Tsu, Japan
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Nagy L, Vonk P, Künzler M, Földi C, Virágh M, Ohm R, Hennicke F, Bálint B, Csernetics Á, Hegedüs B, Hou Z, Liu X, Nan S, Pareek M, Sahu N, Szathmári B, Varga T, Wu H, Yang X, Merényi Z. Lessons on fruiting body morphogenesis from genomes and transcriptomes of Agaricomycetes. Stud Mycol 2023; 104:1-85. [PMID: 37351542 PMCID: PMC10282164 DOI: 10.3114/sim.2022.104.01] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 12/02/2022] [Indexed: 01/09/2024] Open
Abstract
Fruiting bodies (sporocarps, sporophores or basidiomata) of mushroom-forming fungi (Agaricomycetes) are among the most complex structures produced by fungi. Unlike vegetative hyphae, fruiting bodies grow determinately and follow a genetically encoded developmental program that orchestrates their growth, tissue differentiation and sexual sporulation. In spite of more than a century of research, our understanding of the molecular details of fruiting body morphogenesis is still limited and a general synthesis on the genetics of this complex process is lacking. In this paper, we aim at a comprehensive identification of conserved genes related to fruiting body morphogenesis and distil novel functional hypotheses for functionally poorly characterised ones. As a result of this analysis, we report 921 conserved developmentally expressed gene families, only a few dozens of which have previously been reported to be involved in fruiting body development. Based on literature data, conserved expression patterns and functional annotations, we provide hypotheses on the potential role of these gene families in fruiting body development, yielding the most complete description of molecular processes in fruiting body morphogenesis to date. We discuss genes related to the initiation of fruiting, differentiation, growth, cell surface and cell wall, defence, transcriptional regulation as well as signal transduction. Based on these data we derive a general model of fruiting body development, which includes an early, proliferative phase that is mostly concerned with laying out the mushroom body plan (via cell division and differentiation), and a second phase of growth via cell expansion as well as meiotic events and sporulation. Altogether, our discussions cover 1 480 genes of Coprinopsis cinerea, and their orthologs in Agaricus bisporus, Cyclocybe aegerita, Armillaria ostoyae, Auriculariopsis ampla, Laccaria bicolor, Lentinula edodes, Lentinus tigrinus, Mycena kentingensis, Phanerochaete chrysosporium, Pleurotus ostreatus, and Schizophyllum commune, providing functional hypotheses for ~10 % of genes in the genomes of these species. Although experimental evidence for the role of these genes will need to be established in the future, our data provide a roadmap for guiding functional analyses of fruiting related genes in the Agaricomycetes. We anticipate that the gene compendium presented here, combined with developments in functional genomics approaches will contribute to uncovering the genetic bases of one of the most spectacular multicellular developmental processes in fungi. Citation: Nagy LG, Vonk PJ, Künzler M, Földi C, Virágh M, Ohm RA, Hennicke F, Bálint B, Csernetics Á, Hegedüs B, Hou Z, Liu XB, Nan S, M. Pareek M, Sahu N, Szathmári B, Varga T, Wu W, Yang X, Merényi Z (2023). Lessons on fruiting body morphogenesis from genomes and transcriptomes of Agaricomycetes. Studies in Mycology 104: 1-85. doi: 10.3114/sim.2022.104.01.
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Affiliation(s)
- L.G. Nagy
- Synthetic and Systems Biology Unit, Biological Research Center, Szeged, 6726, Hungary;
| | - P.J. Vonk
- Microbiology, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands;
| | - M. Künzler
- Institute of Microbiology, Department of Biology, Eidgenössische Technische Hochschule (ETH) Zürich, Zürich, Switzerland;
| | - C. Földi
- Synthetic and Systems Biology Unit, Biological Research Center, Szeged, 6726, Hungary;
| | - M. Virágh
- Synthetic and Systems Biology Unit, Biological Research Center, Szeged, 6726, Hungary;
| | - R.A. Ohm
- Microbiology, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands;
| | - F. Hennicke
- Project Group Genetics and Genomics of Fungi, Chair Evolution of Plants and Fungi, Ruhr-University Bochum, 44780, Bochum, North Rhine-Westphalia, Germany;
| | - B. Bálint
- Synthetic and Systems Biology Unit, Biological Research Center, Szeged, 6726, Hungary;
| | - Á. Csernetics
- Synthetic and Systems Biology Unit, Biological Research Center, Szeged, 6726, Hungary;
| | - B. Hegedüs
- Synthetic and Systems Biology Unit, Biological Research Center, Szeged, 6726, Hungary;
| | - Z. Hou
- Synthetic and Systems Biology Unit, Biological Research Center, Szeged, 6726, Hungary;
| | - X.B. Liu
- Synthetic and Systems Biology Unit, Biological Research Center, Szeged, 6726, Hungary;
| | - S. Nan
- Institute of Applied Mycology, Huazhong Agricultural University, 430070 Hubei Province, PR China
| | - M. Pareek
- Synthetic and Systems Biology Unit, Biological Research Center, Szeged, 6726, Hungary;
| | - N. Sahu
- Synthetic and Systems Biology Unit, Biological Research Center, Szeged, 6726, Hungary;
| | - B. Szathmári
- Synthetic and Systems Biology Unit, Biological Research Center, Szeged, 6726, Hungary;
| | - T. Varga
- Synthetic and Systems Biology Unit, Biological Research Center, Szeged, 6726, Hungary;
| | - H. Wu
- Synthetic and Systems Biology Unit, Biological Research Center, Szeged, 6726, Hungary;
| | - X. Yang
- Institute of Applied Mycology, Huazhong Agricultural University, 430070 Hubei Province, PR China
| | - Z. Merényi
- Synthetic and Systems Biology Unit, Biological Research Center, Szeged, 6726, Hungary;
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6
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Identification and biochemical characterization of a novel N-acetylglucosamine kinase in Saccharomyces cerevisiae. Sci Rep 2022; 12:16991. [PMID: 36216916 PMCID: PMC9550789 DOI: 10.1038/s41598-022-21400-3] [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: 06/09/2022] [Accepted: 09/27/2022] [Indexed: 12/29/2022] Open
Abstract
N-acetylglucosamine (GlcNAc) is a key component of glycans such as glycoprotein and the cell wall. GlcNAc kinase is an enzyme that transfers a phosphate onto GlcNAc to generate GlcNAc-6-phosphate, which can be a precursor for glycan synthesis. GlcNAc kinases have been found in a broad range of organisms, including pathogenic yeast, human and bacteria. However, this enzyme has never been discovered in Saccharomyces cerevisiae, a eukaryotic model. In this study, the first GlcNAc kinase from S. cerevisiae was identified and named Ngk1. The Km values of Ngk1 for GlcNAc and glucose were 0.11 mM and 71 mM, respectively, suggesting that Ngk1 possesses a high affinity for GlcNAc, unlike hexokinases. Ngk1 showed the GlcNAc phosphorylation activity with various nucleoside triphosphates, namely ATP, CTP, GTP, ITP, and UTP, as phosphoryl donors. Ngk1 is phylogenetically distant from known enzymes, as the amino acid sequence identity with others is only about 20% or less. The physiological role of Ngk1 in S. cerevisiae is also discussed.
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7
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Functional Characterization of the GlcNAc Catabolic Pathway in Cryptococcus deneoformans. Appl Environ Microbiol 2022; 88:e0043722. [PMID: 35736228 PMCID: PMC9275227 DOI: 10.1128/aem.00437-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The amino sugar N-acetyl-d-glucosamine (GlcNAc) is the key constituent of cell wall components and plays an important role in pathogenesis in a wide range of fungi. However, catabolism of GlcNAc has not been studied in basidiomycete fungi. In this study, we identified and characterized a gene cluster essential for GlcNAc utilization in Cryptococcus deneoformans, an environmental human fungal pathogen. The C. deneoformans genome contains a GlcNAc transporter (Ngt1), a GlcNAc kinase (Hxk3), a GlcNAc-6-phosphate deacetylase (Dac1), and a glucosamine-6-phosphate deaminase (Nag1). Their expression levels were highly induced in cultures containing GlcNAc as the sole carbon source, and the corresponding mutants showed severe growth defects in the presence of GlcNAc. Functional and biochemical analyses revealed that HXK3 encodes a novel GlcNAc kinase. Site-directed mutations of conserved residues of Hxk3 indicated that ATP binding and GlcNAc binding are essential for GlcNAc kinase activities. Taken together, the results from this study provide crucial insights into basidiomycete GlcNAc catabolism. IMPORTANCEN-Acetylglucosamine (GlcNAc) is recognized as not only the building block of chitin but also an important signaling molecule in fungi. The catabolic pathway of GlcNAc also plays an important role in vital biological processes in fungi. However, the utilization pathway of GlcNAc in the phylum Basidiomycota, which contains more than 41,000 species, remains unknown. Cryptococcus deneoformans is a representative basidiomycetous pathogen that causes life-threatening meningitis. In this study, we characterized a gene cluster essential for GlcNAc utilization in C. deneoformans and identified a novel GlcNAc kinase. The results of this study provide important insights into basidiomycete GlcNAc catabolism and offer a starting point for revealing its role in pathogenesis.
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Rao KH, Paul S, Natarajan K, Ghosh S. N-acetylglucosamine kinase, Hxk1is a multifaceted metabolic enzyme in model pathogenic yeast Candida albicans. Microbiol Res 2022; 263:127146. [DOI: 10.1016/j.micres.2022.127146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 07/22/2022] [Accepted: 07/22/2022] [Indexed: 10/16/2022]
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Wijnants S, Vreys J, Van Dijck P. Interesting antifungal drug targets in the central metabolism of Candida albicans. Trends Pharmacol Sci 2021; 43:69-79. [PMID: 34756759 DOI: 10.1016/j.tips.2021.10.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 10/04/2021] [Accepted: 10/05/2021] [Indexed: 01/04/2023]
Abstract
To treat infections caused by Candida albicans, azoles, polyenes, and echinocandins are used. However, resistance occurs against all three, so there is an urgent need for new antifungal drugs with a novel mode of action. Recently, it became clear that central metabolism plays an important role in the virulence of C. albicans. Glycolysis is, for example, upregulated during virulence conditions, whereas the glyoxylate cycle is important upon phagocytosis by host immune cells. These findings indicate that C. albicans adapts its metabolism to the environment for maximal virulence. In this review, we provide an overview of the potency of different central metabolic pathways and their key enzymes as potential antifungal drug targets.
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Affiliation(s)
- Stefanie Wijnants
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, Leuven, Belgium; VIB-KU Leuven Center for Microbiology, Leuven, Belgium
| | - Jolien Vreys
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, Leuven, Belgium; VIB-KU Leuven Center for Microbiology, Leuven, Belgium
| | - Patrick Van Dijck
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, Leuven, Belgium; VIB-KU Leuven Center for Microbiology, Leuven, Belgium.
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Lok B, Adam MAA, Kamal LZM, Chukwudi NA, Sandai R, Sandai D. The assimilation of different carbon sources in Candida albicans: Fitness and pathogenicity. Med Mycol 2021; 59:115-125. [PMID: 32944760 DOI: 10.1093/mmy/myaa080] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 08/07/2020] [Accepted: 08/14/2020] [Indexed: 01/31/2023] Open
Abstract
Candida albicans is a commensal yeast commonly found on the skin and in the body. However, in immunocompromised individuals, the fungi could cause local and systemic infections. The carbon source available plays an important role in the establishment of C. albicans infections. The fungi's ability to assimilate a variety of carbon sources plays a vital role in its colonization, and by extension, its fitness and pathogenicity, as it often inhabits niches that are glucose-limited but rich in alternative carbon sources. A difference in carbon sources affect the growth and mating of C. albicans, which contributes to its pathogenicity as proliferation helps the fungi colonize its environment. The carbon source also affects its metabolism and signaling pathways, which are integral parts of the fungi's fitness and pathogenicity. As a big percentage of the carbon assimilated by C. albicans goes to cell wall biogenesis, the availability of different carbon sources will result in cell walls with variations in rigidity, adhesion, and surface hydrophobicity. In addition to the biofilm formation of the fungi, the carbon source also influences whether the fungi grow in yeast- or mycelial-form. Both forms play different roles in C. albicans's infection process. A better understanding of the role of the carbon sources in C. albicans's pathogenicity would contribute to more effective treatment solutions for fungal infections.
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Affiliation(s)
- Bronwyn Lok
- Infectomics Cluster, Advance Medical and Dental Institute, Universiti Sains Malaysia, Penang, Malaysia
| | - Mowaffaq Adam Ahmad Adam
- Infectomics Cluster, Advance Medical and Dental Institute, Universiti Sains Malaysia, Penang, Malaysia
| | - Laina Zarisa Mohd Kamal
- Infectomics Cluster, Advance Medical and Dental Institute, Universiti Sains Malaysia, Penang, Malaysia
| | - Nwakpa Anthony Chukwudi
- Infectomics Cluster, Advance Medical and Dental Institute, Universiti Sains Malaysia, Penang, Malaysia
| | - Rosline Sandai
- Faculty of Languages and Communication, Universiti Pendidikan Sultan Idris, Perak Darul Ridzuan, Malaysia
| | - Doblin Sandai
- Infectomics Cluster, Advance Medical and Dental Institute, Universiti Sains Malaysia, Penang, Malaysia
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11
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Venkatesh A, Murray AL, Coughlan AY, Wolfe KH. Giant GAL gene clusters for the melibiose-galactose pathway in Torulaspora. Yeast 2021; 38:117-126. [PMID: 33141945 PMCID: PMC7898345 DOI: 10.1002/yea.3532] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 10/20/2020] [Accepted: 10/23/2020] [Indexed: 12/19/2022] Open
Abstract
In many yeast species, the three genes at the centre of the galactose catabolism pathway, GAL1, GAL10 and GAL7, are neighbours in the genome and form a metabolic gene cluster. We report here that some yeast strains in the genus Torulaspora have much larger GAL clusters that include genes for melibiase (MEL1), galactose permease (GAL2), glucose transporter (HGT1), phosphoglucomutase (PGM1) and the transcription factor GAL4, in addition to GAL1, GAL10, and GAL7. Together, these eight genes encode almost all the steps in the pathway for catabolism of extracellular melibiose (a disaccharide of galactose and glucose). We show that a progenitor 5-gene cluster containing GAL 7-1-10-4-2 was likely present in the common ancestor of Torulaspora and Zygotorulaspora. It added PGM1 and MEL1 in the ancestor of most Torulaspora species. It underwent further expansion in the T. pretoriensis clade, involving the fusion of three progenitor clusters in tandem and the gain of HGT1. These giant GAL clusters are highly polymorphic in structure, and subject to horizontal transfers, pseudogenization and gene losses. We identify recent horizontal transfers of complete GAL clusters from T. franciscae into one strain of T. delbrueckii, and from a relative of T. maleeae into one strain of T. globosa. The variability and dynamic evolution of GAL clusters in Torulaspora indicates that there is strong natural selection on the GAL pathway in this genus.
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Affiliation(s)
- Anjan Venkatesh
- UCD Conway Institute and School of MedicineUniversity College DublinDublinIreland
| | - Anthony L. Murray
- UCD Conway Institute and School of MedicineUniversity College DublinDublinIreland
| | - Aisling Y. Coughlan
- UCD Conway Institute and School of MedicineUniversity College DublinDublinIreland
| | - Kenneth H. Wolfe
- UCD Conway Institute and School of MedicineUniversity College DublinDublinIreland
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12
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Pennerman KK, Yin G, Glenn AE, Bennett JW. Identifying candidate Aspergillus pathogenicity factors by annotation frequency. BMC Microbiol 2020; 20:342. [PMID: 33176679 PMCID: PMC7661267 DOI: 10.1186/s12866-020-02031-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 11/02/2020] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Members of the genus Aspergillus display a variety of lifestyles, ranging from saprobic to pathogenic on plants and/or animals. Increased genome sequencing of economically important members of the genus permits effective use of "-omics" comparisons between closely related species and strains to identify candidate genes that may contribute to phenotypes of interest, especially relating to pathogenicity. Protein-coding genes were predicted from 216 genomes of 12 Aspergillus species, and the frequencies of various structural aspects (exon count and length, intron count and length, GC content, and codon usage) and functional annotations (InterPro, Gene Ontology, and Kyoto Encyclopedia of Genes and Genomes terms) were compared. RESULTS Using principal component analyses, the three sets of functional annotations for each strain were clustered by species. The species clusters appeared to separate by pathogenicity on plants along the first dimensions, which accounted for over 20% of the variance. More annotations for genes encoding pectinases and secondary metabolite biosynthetic enzymes were assigned to phytopathogenic strains from species such as Aspergillus flavus. In contrast, Aspergillus fumigatus strains, which are pathogenic to animals but not plants, were assigned relatively more terms related to phosphate transferases, and carbohydrate and amino-sugar metabolism. Analyses of publicly available RNA-Seq data indicated that one A. fumigatus protein among 17 amino-sugar processing candidates, a hexokinase, was up-regulated during co-culturing with human immune system cells. CONCLUSION Genes encoding hexokinases and other proteins of interest may be subject to future manipulations to further refine understanding of Aspergillus pathogenicity factors.
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Affiliation(s)
- Kayla K Pennerman
- United States Department of Agriculture, Toxicology and Mycotoxin Research Unit, Athens, GA, 30605, USA.
| | - Guohua Yin
- Department of Plant Biology, Rutgers University, The State University of New Jersey, New Brunswick, NJ, 08901, USA
| | - Anthony E Glenn
- United States Department of Agriculture, Toxicology and Mycotoxin Research Unit, Athens, GA, 30605, USA
| | - Joan W Bennett
- Department of Plant Biology, Rutgers University, The State University of New Jersey, New Brunswick, NJ, 08901, USA
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13
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N-Acetylglucosamine (GlcNAc) Sensing, Utilization, and Functions in Candida albicans. J Fungi (Basel) 2020; 6:jof6030129. [PMID: 32784532 PMCID: PMC7558947 DOI: 10.3390/jof6030129] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 07/25/2020] [Accepted: 07/29/2020] [Indexed: 12/16/2022] Open
Abstract
The sensing and efficient utilization of environmental nutrients are critical for the survival of microorganisms in environments where nutrients are limited, such as within mammalian hosts. Candida albicans is a common member of the human microbiota as well as an opportunistic fungal pathogen. The amide derivative sugar N-acetlyglucosamine (GlcNAc) is an important signaling molecule for C. albicans that could be a major nutrient source for this fungus in host settings. In this article, we review progress made over the past two decades on GlcNAc utilization, sensing, and functions in C. albicans and its related fungal species. GlcNAc sensing and catabolic pathways have been intensively studied in C. albicans. The C. albicans protein Ngt1 represents the first identified GlcNAc-specific transporter in eukaryotic organisms. In C. albicans, GlcNAc not only induces morphological transitions including the yeast to hyphal transition and the white to opaque phenotypic switch, but it also promotes fungal cell death. The Ras-cAMP/PKA signaling pathway plays critical roles in regulating these processes. Given the importance of GlcNAc sensing and utilization in C. albicans, targeting GlcNAc associated pathways and key pathway components could be promising in the development of new antifungal strategies.
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Song YD, Hsu CC, Lew SQ, Lin CH. Candida tropicalis RON1 is required for hyphal formation, biofilm development, and virulence but is dispensable for N-acetylglucosamine catabolism. Med Mycol 2020; 59:379-391. [PMID: 32712662 DOI: 10.1093/mmy/myaa063] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 06/29/2020] [Accepted: 07/08/2020] [Indexed: 01/05/2023] Open
Abstract
NDT80-like family genes are highly conserved across a large group of fungi, but the functions of each Ndt80 protein are diverse and have evolved differently among yeasts and pathogens. The unique NDT80 gene in budding yeast is required for sexual reproduction, whereas three NDT80-like genes, namely, NDT80, REP1, and RON1, found in Candida albicans exhibit distinct functions. Notably, it was suggested that REP1, rather than RON1, is required for N-acetylglucosamine (GlcNAc) catabolism. Although Candida tropicalis, a widely dispersed fungal pathogen in tropical and subtropical areas, is closely related to Candida albicans, its phenotypic, pathogenic and environmental adaptation characteristics are remarkably divergent. In this study, we focused on the Ron1 transcription factor in C. tropicalis. Protein alignment showed that C. tropicalis Ron1 (CtRon1) shares 39.7% identity with C. albicans Ron1 (CaRon1). Compared to the wild-type strain, the C. tropicalis ron1Δ strains exhibited normal growth in different carbon sources and had similar expression levels of several GlcNAc catabolic genes during GlcNAc treatment. In contrast, C. tropicalis REP1 is responsible for GlcNAc catabolism and is involved in GlcNAc catabolic gene expressions, similar to C. albicans Rep1. However, REP1 deletion strains in C. tropicalis promote hyphal development in GlcNAc with low glucose content. Interestingly, CtRON1, but not CaRON1, deletion mutants exhibited significantly impaired hyphal growth and biofilm formation. As expected, CtRON1 was required for full virulence. Together, the results of this study showed divergent functions of CtRon1 compared to CaRon1; CtRon1 plays a key role in yeast-hyphal dimorphism, biofilm formation and virulence. LAY ABSTRACT In this study, we identified the role of RON1, an NDT80-like gene, in Candida tropicalis. Unlike the gene in Candida albicans, our studies showed that RON1 is a key regulator of hyphal formation, biofilm development and virulence but is dispensable for N-acetylglucosamine catabolism in C. tropicalis.
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Affiliation(s)
- Yu-De Song
- Department of Biochemical Science and Technology, College of Life Science, National Taiwan University, Taipei, Taiwan
| | - Chih-Chieh Hsu
- Department of Biochemical Science and Technology, College of Life Science, National Taiwan University, Taipei, Taiwan
| | - Shi Qian Lew
- Department of Biochemical Science and Technology, College of Life Science, National Taiwan University, Taipei, Taiwan
| | - Ching-Hsuan Lin
- Department of Biochemical Science and Technology, College of Life Science, National Taiwan University, Taipei, Taiwan
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Singh M, Singh N. DNA Barcoding for Species Identification in Genetically Engineered Fungi. Fungal Biol 2020. [DOI: 10.1007/978-3-030-41870-0_16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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16
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Min K, Naseem S, Konopka JB. N-Acetylglucosamine Regulates Morphogenesis and Virulence Pathways in Fungi. J Fungi (Basel) 2019; 6:jof6010008. [PMID: 31878148 PMCID: PMC7151181 DOI: 10.3390/jof6010008] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 12/17/2019] [Accepted: 12/19/2019] [Indexed: 12/17/2022] Open
Abstract
N-acetylglucosamine (GlcNAc) is being increasingly recognized for its ability to stimulate cell signaling. This amino sugar is best known as a component of cell wall peptidoglycan in bacteria, cell wall chitin in fungi and parasites, exoskeletons of arthropods, and the extracellular matrix of animal cells. In addition to these structural roles, GlcNAc is now known to stimulate morphological and stress responses in a wide range of organisms. In fungi, the model organisms Saccharomyces cerevisiae and Schizosaccharomyces pombe lack the ability to respond to GlcNAc or catabolize it, so studies with the human pathogen Candida albicans have been providing new insights into the ability of GlcNAc to stimulate cellular responses. GlcNAc potently induces C. albicans to transition from budding to filamentous hyphal growth. It also promotes an epigenetic switch from White to Opaque cells, which differ in morphology, metabolism, and virulence properties. These studies have led to new discoveries, such as the identification of the first eukaryotic GlcNAc transporter. Other results have shown that GlcNAc can induce signaling in C. albicans in two ways. One is to act as a signaling molecule independent of its catabolism, and the other is that its catabolism can cause the alkalinization of the extracellular environment, which provides an additional stimulus to form hyphae. GlcNAc also induces the expression of virulence genes in the C. albicans, indicating it can influence pathogenesis. Therefore, this review will describe the recent advances in understanding the role of GlcNAc signaling pathways in regulating C. albicans morphogenesis and virulence.
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Petrucelli MF, Matsuda JB, Peroni K, Sanches PR, Silva WA, Beleboni RO, Martinez-Rossi NM, Marins M, Fachin AL. The Transcriptional Profile of Trichophyton rubrum Co-Cultured with Human Keratinocytes Shows New Insights about Gene Modulation by Terbinafine. Pathogens 2019; 8:pathogens8040274. [PMID: 31795354 PMCID: PMC6963840 DOI: 10.3390/pathogens8040274] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Revised: 11/20/2019] [Accepted: 11/22/2019] [Indexed: 11/16/2022] Open
Abstract
The dermatophyte Trichophyton rubrum is the main causative agent of dermatophytoses worldwide. Although a superficial mycosis, its incidence has been increasing especially among diabetic and immunocompromised patients. Terbinafine is commonly used for the treatment of infections caused by dermatophytes. However, cases of resistance of T. rubrum to this allylamine were reported even with the efficacy of this drug. The present study is the first to evaluate the effect of terbinafine using a co-culture model of T. rubrum and human keratinocytes, mimicking a fungus-host interaction, in conjunction with RNA-seq technique. Our data showed the repression of several genes involved in the ergosterol biosynthesis cascade and the induction of genes encoding major facilitator superfamily (MFS)- and ATP-binding cassette superfamily (ABC)-type membrane transporter which may be involved in T. rubrum mechanisms of resistance to this drug. We observed that some genes reported in the scientific literature as candidates of new antifungal targets were also modulated. In addition, we found the modulation of several genes that are hypothetical in T. rubrum but that possess known orthologs in other dermatophytes. Taken together, the results indicate that terbinafine can act on various targets related to the physiology of T. rubrum other than its main target of ergosterol biosynthetic pathway.
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Affiliation(s)
- Monise Fazolin Petrucelli
- Biotechnology Unit, University of Ribeirão Preto-UNAERP, Av. Costábile Romano 2201, Ribeirão Preto 14960-900, SP, Brazil; (M.F.P.); (J.B.M.); (R.O.B.); (M.M.)
| | - Josie Budag Matsuda
- Biotechnology Unit, University of Ribeirão Preto-UNAERP, Av. Costábile Romano 2201, Ribeirão Preto 14960-900, SP, Brazil; (M.F.P.); (J.B.M.); (R.O.B.); (M.M.)
| | - Kamila Peroni
- National Institute of Science and Technology in Stem Cell and Cell Therapy, Center for Cell-Based Therapy, Ribeirão Preto 14051-140, SP, Brazil; (K.P.)
| | - Pablo Rodrigo Sanches
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto 14049-900, SP, Brazil; (P.R.S.); (N.M.M.-R.)
| | - Wilson Araújo Silva
- National Institute of Science and Technology in Stem Cell and Cell Therapy, Center for Cell-Based Therapy, Ribeirão Preto 14051-140, SP, Brazil; (K.P.)
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto 14049-900, SP, Brazil; (P.R.S.); (N.M.M.-R.)
- Center for Integrative System Biology-CISBi-NAP/USP, University of São Paulo, Ribeirão Preto 14049-900, SP, Brazil
- Center for Medical Genomics, University Hospital of the Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto 14015-010, SP, Brazil
| | - Rene Oliveira Beleboni
- Biotechnology Unit, University of Ribeirão Preto-UNAERP, Av. Costábile Romano 2201, Ribeirão Preto 14960-900, SP, Brazil; (M.F.P.); (J.B.M.); (R.O.B.); (M.M.)
| | - Nilce Maria Martinez-Rossi
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto 14049-900, SP, Brazil; (P.R.S.); (N.M.M.-R.)
| | - Mozart Marins
- Biotechnology Unit, University of Ribeirão Preto-UNAERP, Av. Costábile Romano 2201, Ribeirão Preto 14960-900, SP, Brazil; (M.F.P.); (J.B.M.); (R.O.B.); (M.M.)
| | - Ana Lúcia Fachin
- Biotechnology Unit, University of Ribeirão Preto-UNAERP, Av. Costábile Romano 2201, Ribeirão Preto 14960-900, SP, Brazil; (M.F.P.); (J.B.M.); (R.O.B.); (M.M.)
- Correspondence: or ; Fax: +55-16-36037030
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Laurian R, Dementhon K, Doumèche B, Soulard A, Noel T, Lemaire M, Cotton P. Hexokinase and Glucokinases Are Essential for Fitness and Virulence in the Pathogenic Yeast Candida albicans. Front Microbiol 2019; 10:327. [PMID: 30858840 PMCID: PMC6401654 DOI: 10.3389/fmicb.2019.00327] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Accepted: 02/08/2019] [Indexed: 01/28/2023] Open
Abstract
The pathogenic yeast Candida albicans is both a powerful commensal and a pathogen of humans that can infect wide range of organs and body sites. Metabolic flexibility promotes infection and commensal colonization by this opportunistic pathogen. Yeast cell survival depends upon assimilation of fermentable and non-fermentable locally available carbon sources. Physiologically relevant sugars like glucose and fructose are present at low levels in host niches. However, because glucose is the preferred substrate for energy and biosynthesis of structural components, its efficient detection and metabolism are fundamental for the metabolic adaptation of the pathogen. We explored and characterized the C. albicans hexose kinase system composed of one hexokinase (CaHxk2) and two glucokinases (CaGlk1 and CaGlk4). Using a set of mutant strains, we found that hexose phosphorylation is mostly performed by CaHxk2, which sustains growth on hexoses. Our data on hexokinase and glucokinase expression point out an absence of cross regulation mechanisms at the transcription level and different regulatory pathways. In the presence of glucose, CaHxk2 migrates in the nucleus and contributes to the glucose repression signaling pathway. In addition, CaHxk2 participates in oxidative, osmotic and cell wall stress responses, while glucokinases are overexpressed under hypoxia. Hexose phosphorylation is a key step necessary for filamentation that is affected in the hexokinase mutant. Virulence of this mutant is clearly impacted in the Galleria mellonella and macrophage models. Filamentation, glucose phosphorylation and stress response defects of the hexokinase mutant prevent host killing by C. albicans. By contributing to metabolic flexibility, stress response and morphogenesis, hexose kinase enzymes play an essential role in the virulence of C. albicans.
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Affiliation(s)
- Romain Laurian
- Génétique Moléculaire des Levures, UMR-CNRS 5240 Microbiologie Adaptation et Pathogénie, Université de Lyon – Université Lyon 1, Lyon, France
| | - Karine Dementhon
- Laboratoire de Microbiologie Fondamentale et Pathogénicité, UMR-CNRS 5234, Université de Bordeaux, Bordeaux, France
| | - Bastien Doumèche
- Institut de Chimie et Biochimie Moléculaires et Supramoléculaires, Université de Lyon – Université Lyon 1, Lyon, France
| | - Alexandre Soulard
- Génétique Moléculaire des Levures, UMR-CNRS 5240 Microbiologie Adaptation et Pathogénie, Université de Lyon – Université Lyon 1, Lyon, France
| | - Thierry Noel
- Laboratoire de Microbiologie Fondamentale et Pathogénicité, UMR-CNRS 5234, Université de Bordeaux, Bordeaux, France
| | - Marc Lemaire
- Génétique Moléculaire des Levures, UMR-CNRS 5240 Microbiologie Adaptation et Pathogénie, Université de Lyon – Université Lyon 1, Lyon, France
| | - Pascale Cotton
- Génétique Moléculaire des Levures, UMR-CNRS 5240 Microbiologie Adaptation et Pathogénie, Université de Lyon – Université Lyon 1, Lyon, France
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Van Ende M, Wijnants S, Van Dijck P. Sugar Sensing and Signaling in Candida albicans and Candida glabrata. Front Microbiol 2019; 10:99. [PMID: 30761119 PMCID: PMC6363656 DOI: 10.3389/fmicb.2019.00099] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 01/16/2019] [Indexed: 12/30/2022] Open
Abstract
Candida species, such as Candida albicans and Candida glabrata, cause infections at different host sites because they adapt their metabolism depending on the available nutrients. They are able to proliferate under both nutrient-rich and nutrient-poor conditions. This adaptation is what makes these fungi successful pathogens. For both species, sugars are very important nutrients and as the sugar level differs depending on the host niche, different sugar sensing systems must be present. Saccharomyces cerevisiae has been used as a model for the identification of these sugar sensing systems. One of the main carbon sources for yeast is glucose, for which three different pathways have been described. First, two transporter-like proteins, ScSnf3 and ScRgt2, sense glucose levels resulting in the induction of different hexose transporter genes. This situation is comparable in C. albicans and C. glabrata, where sensing of glucose by CaHgt4 and CgSnf3, respectively, also results in hexose transporter gene induction. The second glucose sensing mechanism in S. cerevisiae is via the G-protein coupled receptor ScGpr1, which causes the activation of the cAMP/PKA pathway, resulting in rapid adaptation to the presence of glucose. The main components of this glucose sensing system are also conserved in C. albicans and C. glabrata. However, it seems that the ligand(s) for CaGpr1 are not sugars but lactate and methionine. In C. glabrata, this pathway has not yet been investigated. Finally, the glucose repression pathway ensures repression of respiration and repression of the use of alternative carbon sources. This pathway is not well characterized in Candida species. It is important to note that, apart from glucose, other sugars and sugar-analogs, such as N-acetylglucosamine in the case of C. albicans, are also important carbon sources. In these fungal pathogens, sensing sugars is important for a number of virulence attributes, including adhesion, oxidative stress resistance, biofilm formation, morphogenesis, invasion, and antifungal drug tolerance. In this review, the sugar sensing and signaling mechanisms in these Candida species are compared to S. cerevisiae.
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Affiliation(s)
- Mieke Van Ende
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, Department of Biology, KU Leuven, Leuven, Belgium
- VIB-KU Leuven Center for Microbiology, Leuven, Belgium
| | - Stefanie Wijnants
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, Department of Biology, KU Leuven, Leuven, Belgium
- VIB-KU Leuven Center for Microbiology, Leuven, Belgium
| | - Patrick Van Dijck
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, Department of Biology, KU Leuven, Leuven, Belgium
- VIB-KU Leuven Center for Microbiology, Leuven, Belgium
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20
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Camacho E, Chrissian C, Cordero RJB, Liporagi-Lopes L, Stark RE, Casadevall A. N-acetylglucosamine affects Cryptococcus neoformans cell-wall composition and melanin architecture. MICROBIOLOGY-SGM 2017; 163:1540-1556. [PMID: 29043954 DOI: 10.1099/mic.0.000552] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Cryptococcus neoformans is an environmental fungus that belongs to the phylum Basidiomycetes and is a major pathogen in immunocompromised patients. The ability of C. neoformans to produce melanin pigments represents its second most important virulence factor, after the presence of a polysaccharide capsule. Both the capsule and melanin are closely associated with the fungal cell wall, a complex structure that is essential for maintaining cell morphology and viability under conditions of stress. The amino sugar N-acetylglucosamine (GlcNAc) is a key constituent of the cell-wall chitin and is used for both N-linked glycosylation and GPI anchor synthesis. Recent studies have suggested additional roles for GlcNAc as an activator and mediator of cellular signalling in fungal and plant cells. Furthermore, chitin and chitosan polysaccharides interact with melanin pigments in the cell wall and have been found to be essential for melanization. Despite the importance of melanin, its molecular structure remains unresolved; however, we previously obtained critical insights using advanced nuclear magnetic resonance (NMR) and imaging techniques. In this study, we investigated the effect of GlcNAc supplementation on cryptococcal cell-wall composition and melanization. C. neoformans was able to metabolize GlcNAc as a sole source of carbon and nitrogen, indicating a capacity to use a component of a highly abundant polymer in the biospherenutritionally. C. neoformans cells grown with GlcNAc manifested changes in the chitosan cell-wall content, cell-wall thickness and capsule size. Supplementing cultures with isotopically 15N-labelled GlcNAc demonstrated that the exogenous monomer serves as a building block for chitin/chitosan and is incorporated into the cell wall. The altered chitin-to-chitosan ratio had no negative effects on the mother-daughter cell separation; growth with GlcNAc affected the fungal cell-wall scaffold, resulting in increased melanin deposition and assembly. In summary, GlcNAc supplementation had pleiotropic effects on cell-wall and melanin architectures, and thus established its capacity to perturb these structures, a property that could prove useful for metabolic tracking studies.
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Affiliation(s)
- Emma Camacho
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Christine Chrissian
- PhD Program in Biochemistry, The Graduate Center of the City University of New York, New York, NY, USA.,Department of Chemistry and Biochemistry and CUNY Institute for Macromolecular Assemblies, The City College of New York, New York, NY, USA
| | - Radames J B Cordero
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Livia Liporagi-Lopes
- Faculdade de Farmácia, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Ruth E Stark
- PhD Program in Biochemistry, The Graduate Center of the City University of New York, New York, NY, USA.,Department of Chemistry and Biochemistry and CUNY Institute for Macromolecular Assemblies, The City College of New York, New York, NY, USA.,PhD Program in Chemistry, The Graduate Center of the City University of New York, New York, NY, USA
| | - Arturo Casadevall
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
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Regulation of Hyphal Growth and N-Acetylglucosamine Catabolism by Two Transcription Factors in Candida albicans. Genetics 2017; 206:299-314. [PMID: 28348062 DOI: 10.1534/genetics.117.201491] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Accepted: 03/24/2017] [Indexed: 02/07/2023] Open
Abstract
The amino sugar N-acetylglucosamine (GlcNAc) is increasingly recognized as an important signaling molecule in addition to its well-known structural roles at the cell surface. In the human fungal pathogen Candida albicans, GlcNAc stimulates several responses including the induction of the genes needed for its catabolism and a switch from budding to filamentous hyphal growth. We identified two genes needed for growth on GlcNAc (RON1 and NGS1) and found that mutants lacking these genes fail to induce the genes needed for GlcNAc catabolism. NGS1 was also important for growth on other sugars, such as maltose, but RON1 appeared to be specific for GlcNAc. Both mutants could grow on nonfermentable carbon sources indicating that they do not affect mitochondrial function, which we show is important for growth on GlcNAc but not for GlcNAc induction of hyphal morphogenesis. Interestingly, both the ron1Δ and ngs1Δ mutants were defective in forming hyphae in response to GlcNAc, even though GlcNAc catabolism is not required for induction of hyphal morphogenesis. The ron1Δ mutant showed a partial defect in forming hyphae, which was surprising since it displayed an elevated level of filamentous cells under noninducing conditions. The ron1Δ mutant also displayed an elevated basal level of expression of genes that are normally upregulated during hyphal growth. Consistent with this, Ron1 contains an Ndt80-like DNA-binding domain, indicating that it regulates gene expression. Thus, Ron1 is a key new component of the GlcNAc response pathway that acts as both an activator and a repressor of hyphal morphogenesis.
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Affiliation(s)
- Pedro Miramón
- Department of Microbiology and Molecular Genetics, The University of Texas Health Science Center, Houston, Texas, United States of America
| | - Michael C. Lorenz
- Department of Microbiology and Molecular Genetics, The University of Texas Health Science Center, Houston, Texas, United States of America
- * E-mail:
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Su C, Lu Y, Liu H. N-acetylglucosamine sensing by a GCN5-related N-acetyltransferase induces transcription via chromatin histone acetylation in fungi. Nat Commun 2016; 7:12916. [PMID: 27694804 PMCID: PMC5063960 DOI: 10.1038/ncomms12916] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Accepted: 08/16/2016] [Indexed: 12/11/2022] Open
Abstract
N-acetylglucosamine (GlcNAc) exists ubiquitously as a component of the surface on a wide range of cells, from bacteria to humans. Many fungi are able to utilize environmental GlcNAc to support growth and induce cellular development, a property important for their survival in various host niches. However, how the GlcNAc signal is sensed and subsequently transduced is largely unknown. Here, we identify a gene that is essential for GlcNAc signalling (NGS1) in Candida albicans, a commensal and pathogenic yeast of humans. Ngs1 can bind GlcNAc through the N-terminal β-N-acetylglucosaminidase homology domain. This binding activates N-acetyltransferase activity in the C-terminal GCN5-related N-acetyltransferase domain, which is required for GlcNAc-induced promoter histone acetylation and transcription. Ngs1 is targeted to the promoters of GlcNAc-inducible genes constitutively by the transcription factor Rep1. Ngs1 is conserved in diverse fungi that have GlcNAc catabolic genes. Thus, fungi use Ngs1 as a GlcNAc-sensor and transducer for GlcNAc-induced transcription. Many fungi are able to metabolise environmental N-acetylglucosamine, however the mechanism by which this molecule is sensed is unclear. Su and Lu et al. show that Candida albicans NGS1 fulfils this function by mediating N-acetylglucosamine-dependent histone acetylation at target genes.
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Affiliation(s)
- Chang Su
- Department of Biological Chemistry, University of California, Irvine, California 92697, USA
| | - Yang Lu
- Department of Biological Chemistry, University of California, Irvine, California 92697, USA
| | - Haoping Liu
- Department of Biological Chemistry, University of California, Irvine, California 92697, USA
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Zhang Q, Tao L, Guan G, Yue H, Liang W, Cao C, Dai Y, Huang G. Regulation of filamentation in the human fungal pathogenCandida tropicalis. Mol Microbiol 2015; 99:528-45. [DOI: 10.1111/mmi.13247] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/12/2015] [Indexed: 12/14/2022]
Affiliation(s)
- Qiuyu Zhang
- State Key Laboratory of Mycology; Institute of Microbiology; Chinese Academy of Sciences; Beijing China
- University of Chinese Academy of Sciences; Beijing China
| | - Li Tao
- State Key Laboratory of Mycology; Institute of Microbiology; Chinese Academy of Sciences; Beijing China
| | - Guobo Guan
- State Key Laboratory of Mycology; Institute of Microbiology; Chinese Academy of Sciences; Beijing China
| | - Huizhen Yue
- State Key Laboratory of Mycology; Institute of Microbiology; Chinese Academy of Sciences; Beijing China
- University of Chinese Academy of Sciences; Beijing China
| | - Weihong Liang
- State Key Laboratory of Mycology; Institute of Microbiology; Chinese Academy of Sciences; Beijing China
- University of Chinese Academy of Sciences; Beijing China
| | - Chengjun Cao
- State Key Laboratory of Mycology; Institute of Microbiology; Chinese Academy of Sciences; Beijing China
- University of Chinese Academy of Sciences; Beijing China
| | - Yu Dai
- State Key Laboratory of Mycology; Institute of Microbiology; Chinese Academy of Sciences; Beijing China
| | - Guanghua Huang
- State Key Laboratory of Mycology; Institute of Microbiology; Chinese Academy of Sciences; Beijing China
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Furo K, Nozaki M, Murashige H, Sato Y. Identification of an N-acetylglucosamine kinase essential for UDP-N-acetylglucosamine salvage synthesis in Arabidopsis. FEBS Lett 2015; 589:3258-62. [PMID: 26408204 DOI: 10.1016/j.febslet.2015.09.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 08/27/2015] [Accepted: 09/08/2015] [Indexed: 01/29/2023]
Abstract
Uridine diphosphate-N-acetylglucosamine (UDP-GlcNAc) donates GlcNAc for various glycans and glycoconjugates. We previously found that GlcNAc supplementation increases the UDP-GlcNAc content in Arabidopsis; however, the metabolic pathway was undefined. Here, we show that the homolog of human GlcNAc kinase (GNK) is conserved in land plants. Enzymatic assays of the Arabidopsis homologous protein (AtGNK) revealed kinase activity that was highly specific for GlcNAc. We also demonstrate the role of AtGNK in plants by using its knockout mutant, which presents lower UDP-GlcNAc contents and is insensitive to GlcNAc supplementation. Moreover, our results demonstrate the presence of a GlcNAc salvage pathway in plants.
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Affiliation(s)
- Keisuke Furo
- Department of Biology, Faculty of Science, Ehime University, 2-5 Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan
| | - Mamoru Nozaki
- Biology and Environmental Science, Graduate School of Science and Engineering, Ehime University, 2-5 Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan
| | - Hiroshi Murashige
- Department of Biology, Faculty of Science, Ehime University, 2-5 Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan
| | - Yasushi Sato
- Biology and Environmental Science, Graduate School of Science and Engineering, Ehime University, 2-5 Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan.
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Dai J, Qu H, Yu Z, Yang J, Zhang H. Computational analysis of AnmK-like kinase: New insights into the cell wall metabolism of fungi. J Theor Biol 2015; 379:59-65. [PMID: 25979372 DOI: 10.1016/j.jtbi.2015.05.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Revised: 04/13/2015] [Accepted: 05/02/2015] [Indexed: 02/02/2023]
Abstract
1,6-Anhydro-N-acetylmuramic acid kinase (AnmK) is the unique enzyme that marks the recycling of the cell wall of Escherichia coli. Here, 81 fungal AnmK-like kinase sequences from 57 fungal species were searched in the NCBI database and a phylogenetic tree was constructed. The three-dimensional structure of an AnmK-like kinase, levoglucosan kinase (LGK) of the yeast Lipomyces starkeyi, was modeled; molecular docking revealed that AnmK and LGK are conserved proteins, and 187Asp, 212Asp are enzymatic residues, respectively. Analysis suggests that 1,6-anhydro-N-acetylglucosamine (anhGlcNAc) and/or 1,6-anhydro-β-d-glucosamine (anhGlcN) would be the appropriate substrates of AnmK-like kinases. Also, the counterparts of other characteristic enzymes of cell wall recycling of bacteria were found in fungi. Taken together, it is proposed that a putative recycling of anhGlcNAc/anhGlcN, which is associated with the hydrolysis of cell walls, exists in fungi. This computational analysis will provide new insights into the metabolism of fungal cell walls.
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Affiliation(s)
- Jianghong Dai
- School of Biology and Pharmaceutical Engineering, Wuhan Polytechnic University, No. 68 Xuefu Road (S), Evergreen Garden, Wuhan 430023, PR China; College of Resources & Environment, University of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing 100049, PR China.
| | - Hong Qu
- Center for Bioinformatics, State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, No. 5 Yiheyuan Road, Beijing 100871, PR China.
| | - Zhisheng Yu
- College of Resources & Environment, University of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing 100049, PR China
| | - Jiangke Yang
- School of Biology and Pharmaceutical Engineering, Wuhan Polytechnic University, No. 68 Xuefu Road (S), Evergreen Garden, Wuhan 430023, PR China
| | - Hongxun Zhang
- College of Resources & Environment, University of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing 100049, PR China
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Genomics and Transcriptomics Analyses of the Oil-Accumulating Basidiomycete Yeast Trichosporon oleaginosus: Insights into Substrate Utilization and Alternative Evolutionary Trajectories of Fungal Mating Systems. mBio 2015. [PMID: 26199329 PMCID: PMC4513080 DOI: 10.1128/mbio.00918-15] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Microbial fermentation of agro-industrial waste holds great potential for reducing the environmental impact associated with the production of lipids for industrial purposes from plant biomass. However, the chemical complexity of many residues currently prevents efficient conversion into lipids, creating a high demand for strains with the ability to utilize all energy-rich components of agricultural residues. Here, we present results of genome and transcriptome analyses of Trichosporon oleaginosus. This oil-accumulating yeast is able to grow on a wide variety of substrates, including pentoses and N-acetylglucosamine, making it an interesting candidate for biotechnological applications. Transcriptomics shows specific changes in gene expression patterns under lipid-accumulating conditions. Furthermore, gene content and expression analyses indicate that T. oleaginosus is well-adapted for the utilization of chitin-rich biomass. We also focused on the T. oleaginosus mating type, because this species is a member of the Tremellomycetes, a group that has been intensively analyzed as a model for the evolution of sexual development, the best-studied member being Cryptococcus neoformans. The structure of the T. oleaginosus mating-type regions differs significantly from that of other Tremellomycetes and reveals a new evolutionary trajectory paradigm. Comparative analysis shows that recruitment of developmental genes to the ancestral tetrapolar mating-type loci occurred independently in the Trichosporon and Cryptococcus lineages, supporting the hypothesis of a trend toward larger mating-type regions in fungi. Finite fossil fuel resources pose sustainability challenges to society and industry. Microbial oils are a sustainable feedstock for biofuel and chemical production that does not compete with food production. We describe genome and transcriptome analyses of the oleaginous yeast Trichosporon oleaginosus, which can accumulate up to 70% of its dry weight as lipids. In contrast to conventional yeasts, this organism not only shows an absence of diauxic effect while fermenting hexoses and pentoses but also effectively utilizes xylose and N-acetylglucosamine, which are building blocks of lignocellulose and chitin, respectively. Transcriptome analysis revealed metabolic networks that govern conversion of xylose or N-acetylglucosamine as well as lipid accumulation. These data form the basis for a targeted strain optimization strategy. Furthermore, analysis of the mating type of T. oleaginosus supports the hypothesis of a trend toward larger mating-type regions in fungi, similar to the evolution of sex chromosomes in animals and plants.
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28
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Flores CL, Gancedo C. The gene YALI0E20207g from Yarrowia lipolytica encodes an N-acetylglucosamine kinase implicated in the regulated expression of the genes from the N-acetylglucosamine assimilatory pathway. PLoS One 2015; 10:e0122135. [PMID: 25816199 PMCID: PMC4376941 DOI: 10.1371/journal.pone.0122135] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Accepted: 02/16/2015] [Indexed: 12/31/2022] Open
Abstract
The non-conventional yeast Yarrowia lipolytica possesses an ORF, YALI0E20207g, which encodes a protein with an amino acid sequence similar to hexokinases from different organisms. We have cloned that gene and determined several enzymatic properties of its encoded protein showing that it is an N-acetylglucosamine (NAGA) kinase. This conclusion was supported by the lack of growth in NAGA of a strain carrying a YALI0E20207g deletion. We named this gene YlNAG5. Expression of YlNAG5 as well as that of the genes encoding the enzymes of the NAGA catabolic pathway-identified by a BLAST search-was induced by this sugar. Deletion of YlNAG5 rendered that expression independent of the presence of NAGA in the medium and reintroduction of the gene restored the inducibility, indicating that YlNag5 participates in the transcriptional regulation of the NAGA assimilatory pathway genes. Expression of YlNAG5 was increased during sporulation and homozygous Ylnag5/Ylnag5 diploid strains sporulated very poorly as compared with a wild type isogenic control strain pointing to a participation of the protein in the process. Overexpression of YlNAG5 allowed growth in glucose of an Ylhxk1glk1 double mutant and produced, in a wild type background, aberrant morphologies in different media. Expression of the gene in a Saccharomyces cerevisiae hxk1 hxk2 glk1 triple mutant restored ability to grow in glucose.
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Affiliation(s)
- Carmen-Lisset Flores
- Department of Metabolism and Cell Signalling, Instituto de Investigaciones Biomédicas “Alberto Sols” CSIC-UAM, Madrid, Spain
- * E-mail:
| | - Carlos Gancedo
- Department of Metabolism and Cell Signalling, Instituto de Investigaciones Biomédicas “Alberto Sols” CSIC-UAM, Madrid, Spain
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29
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Guan G, Wang H, Liang W, Cao C, Tao L, Naseem S, Konopka JB, Wang Y, Huang G. The mitochondrial protein Mcu1 plays important roles in carbon source utilization, filamentation, and virulence in Candida albicans. Fungal Genet Biol 2015; 81:150-9. [PMID: 25626172 DOI: 10.1016/j.fgb.2015.01.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Revised: 01/12/2015] [Accepted: 01/17/2015] [Indexed: 11/28/2022]
Abstract
The fungus Candida albicans is both a pathogen and a commensal in humans. The ability to utilize different carbon sources available in diverse host niches is vital for both commensalism and pathogenicity. N-acetylglucosamine (GlcNAc) is an important signaling molecule as well as a carbon source in C. albicans. Here, we report the discovery of a novel gene MCU1 essential for GlcNAc utilization. Mcu1 is located in mitochondria and associated with multiple energy- and metabolism-related proteins including Por1, Atp1, Pet9, and Mdh1. Consistently, inactivating Por1 impaired GlcNAc utilization as well. Deletion of MCU1 also caused defects in utilizing non-fermentable carbon sources and amino acids. Furthermore, MCU1 is required for filamentation in several inducing conditions and virulence in a mouse systemic infection model. We also deleted TGL99 and GUP1, two genes adjacent to MCU1, and found that the gup1/gup1 mutant exhibited mild defects in the utilization of several carbon sources including GlcNAc, maltose, galactose, amino acids, and ethanol. Our results indicate that MCU1 exists in a cluster of genes involved in the metabolism of carbon sources. Given its importance in metabolism and lack of a homolog in humans, Mcu1 could be a potential target for developing antifungal agents.
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Affiliation(s)
- Guobo Guan
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Haitao Wang
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Proteos, Singapore 138673, Singapore
| | - Weihong Liang
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chengjun Cao
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Li Tao
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Shamoon Naseem
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, NY 11794-5222, USA
| | - James B Konopka
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, NY 11794-5222, USA
| | - Yue Wang
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Proteos, Singapore 138673, Singapore; Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 138673, Singapore
| | - Guanghua Huang
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China.
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Naseem S, Araya E, Konopka JB. Hyphal growth in Candida albicans does not require induction of hyphal-specific gene expression. Mol Biol Cell 2015; 26:1174-87. [PMID: 25609092 PMCID: PMC4357515 DOI: 10.1091/mbc.e14-08-1312] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
GlcNAc activates two pathways in the fungal pathogen Candida albicans. In one pathway, GlcNAc induces hyphal morphology. In the other, GlcNAc metabolism raises the ambient pH, which activates pH signaling pathways to induce gene expression. The dual roles are likely important in other organisms in which GlcNAc is emerging as a key signaling molecule. Various stimuli, including N-acetylglucosamine (GlcNAc), induce the fungal pathogen Candida albicans to switch from budding to hyphal growth. Previous studies suggested that hyphal morphogenesis is stimulated by transcriptional induction of a set of genes that includes known virulence factors. To better understand hyphal development, we examined the role of GlcNAc metabolism using a triple mutant lacking the genes required to metabolize exogenous GlcNAc (hxk1Δ nag1Δ dac1Δ). Surprisingly, at low ambient pH (∼pH 4), GlcNAc stimulated this mutant to form hyphae without obvious induction of hyphal genes. This indicates that GlcNAc can stimulate a separate signal to induce hyphae that is independent of transcriptional responses. Of interest, GlcNAc could induce the triple mutant to express hyphal genes when the medium was buffered to a higher pH (>pH 5), which normally occurs after GlcNAc catabolism. Catabolism of GlcNAc raises the ambient pH rather than acidifying it, as occurs after dextrose catabolism. This synergy between alkalinization and GlcNAc to induce hyphal genes involves the Rim101 pH-sensing pathway; GlcNAc induced rim101Δ and dfg16Δ mutants to form hyphae, but hyphal gene expression was partially defective. These results demonstrate that hyphal morphogenesis and gene expression can be regulated independently, which likely contributes to pathogenesis at different host sites.
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Affiliation(s)
- Shamoon Naseem
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, NY 11794-5222
| | - Esteban Araya
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, NY 11794-5222
| | - James B Konopka
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, NY 11794-5222
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31
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Abstract
Morphogenesis in fungi is often induced by extracellular factors and executed by fungal genetic factors. Cell surface changes and alterations of the microenvironment often accompany morphogenetic changes in fungi. In this review, we will first discuss the general traits of yeast and hyphal morphotypes and how morphogenesis affects development and adaptation by fungi to their native niches, including host niches. Then we will focus on the molecular machinery responsible for the two most fundamental growth forms, yeast and hyphae. Last, we will describe how fungi incorporate exogenous environmental and host signals together with genetic factors to determine their morphotype and how morphogenesis, in turn, shapes the fungal microenvironment.
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Affiliation(s)
- Xiaorong Lin
- Department of Biology, Texas A&M University, College Station, Texas 77843-3258
| | - J Andrew Alspaugh
- Department of Medicine, Division of Infectious Diseases, Duke University Medical Center, Durham, North Carolina 27710
| | - Haoping Liu
- Department of Biological Chemistry, University of California, Irvine, California 92697
| | - Steven Harris
- Center for Plant Science Innovation, University of Nebraska-Lincoln, Lincoln, Nebraska 68588
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32
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Phylogenetic and syntenic analyses of the 12-spanner drug:H(+) antiporter family 1 (DHA1) in pathogenic Candida species: evolution of MDR1 and FLU1 genes. Genomics 2014; 104:45-57. [PMID: 24907457 DOI: 10.1016/j.ygeno.2014.05.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Revised: 05/11/2014] [Accepted: 05/28/2014] [Indexed: 12/22/2022]
Abstract
Candida albicans and other pathogenic Candida species can develop resistance to clinical fungicides through active drug export mediated by multidrug efflux pumps, in particular by members of the drug:H(+) antiporter family 1 (DHA1). The DHA1 proteins encoded in the genomes of 31 hemiascomycetous strains from 25 species were identified and homology relationships between these proteins and the functionally characterised DHA1 in the model yeast Saccharomyces cerevisiae were established. Gene neighbourhood analysis allowed the reconstruction of sixteen DHA1 lineages conserved during the CTG complex species evolution. The evolutionary history of C. albicans MDR1 and FLU1 genes and Candida dubliniensis, Candida tropicalis and Candida parapsilosis MDR1 genes was detailed. Candida genomes show an abundant number of MDR1 and FLU1 homologues but the chromosome environment where MDR1 homologues reside was poorly conserved during evolution. Gene duplication and loss are major mechanisms underlying the evolution of the DHA1 genes in Candida species.
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33
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N-acetylglucosamine (GlcNAc)-inducible gene GIG2 is a novel component of GlcNAc metabolism in Candida albicans. EUKARYOTIC CELL 2013; 13:66-76. [PMID: 24186949 DOI: 10.1128/ec.00244-13] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Candida albicans is an opportunistic fungal pathogen that resides in the human body as a commensal and can turn pathogenic when the host is immunocompromised. Adaptation of C. albicans to host niche-specific conditions is important for the establishment of pathogenicity, where the ability of C. albicans to utilize multiple carbon sources provides additional flexibility. One alternative sugar is N-acetylglucosamine (GlcNAc), which is now established as an important carbon source for many pathogens and can also act as a signaling molecule. Although GlcNAc catabolism has been well studied in many pathogens, the importance of several enzymes involved in the formation of metabolic intermediates still remains elusive. In this context, microarray analysis was carried out to investigate the transcriptional responses induced by GlcNAc under different conditions. A novel gene that was highly upregulated immediately following the GlcNAc catabolic genes was identified and was named GIG2 (GlcNAc-induced gene 2). This gene is regulated in a manner distinct from that of the GlcNAc-induced genes described previously in that GlcNAc metabolism is essential for its induction. Furthermore, this gene is involved in the metabolism of N-acetylneuraminate (sialic acid), a molecule equally important for initial host-pathogen recognition. Mutant cells showed a considerable decrease in fungal burden in mouse kidneys and were hypersensitive to oxidative stress conditions. Since GIG2 is also present in many other fungal and enterobacterial genomes, targeted inhibition of its activity would offer insight into the treatment of candidiasis and other fungal or enterobacterial infections.
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34
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Piacente F, Bernardi C, Marin M, Blanc G, Abergel C, Tonetti MG. Characterization of a UDP-N-acetylglucosamine biosynthetic pathway encoded by the giant DNA virus Mimivirus. Glycobiology 2013; 24:51-61. [PMID: 24107487 DOI: 10.1093/glycob/cwt089] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Mimivirus is a giant DNA virus belonging to the Megaviridae family and infecting unicellular Eukaryotes of the genus Acanthamoeba. The viral particles are characterized by heavily glycosylated surface fibers. Several experiments suggest that Mimivirus and other related viruses encode an autonomous glycosylation system, forming viral glycoproteins independently of their host. In this study, we have characterized three Mimivirus proteins involved in the de novo uridine diphosphate-N-acetylglucosamine (UDP-GlcNAc) production: a glutamine-fructose-6-phosphate transaminase (CDS L619), a glucosamine-6-phosphate N-acetyltransferase (CDS L316) and a UDP-GlcNAc pyrophosphorylase (CDS R689). Sequence and enzymatic analyses have revealed some unique features of the viral pathway. While it follows the eukaryotic-like strategy, it also shares some properties of the prokaryotic pathway. Phylogenetic analyses revealed that the Megaviridae enzymes cluster in monophyletic groups, indicating that they share common ancestors, but did not support the hypothesis of recent acquisitions from one of the known hosts. Rather, viral clades branched at deep nodes in phylogenetic trees, forming independent clades outside sequenced cellular organisms. The intermediate properties between the eukaryotic and prokaryotic pathways, the phylogenetic analyses and the fact that these enzymes are shared between most of the known members of the Megaviridae family altogether suggest that the viral pathway has an ancient origin, resulting from lateral transfers of cellular genes early in the Megaviridae evolution, or from vertical inheritance from a more complex cellular ancestor (reductive evolution hypothesis). The identification of a virus-encoded UDP-GlcNAc pathway reinforces the concept that GlcNAc is a ubiquitous sugar representing a universal and fundamental process in all organisms.
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Affiliation(s)
- Francesco Piacente
- Department of Experimental Medicine, Center of Excellence for Biomedical Research, University of Genova, Viale Benedetto XV, 1 Genova 16132, Italy
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35
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Gilmore SA, Naseem S, Konopka JB, Sil A. N-acetylglucosamine (GlcNAc) triggers a rapid, temperature-responsive morphogenetic program in thermally dimorphic fungi. PLoS Genet 2013; 9:e1003799. [PMID: 24068964 PMCID: PMC3778022 DOI: 10.1371/journal.pgen.1003799] [Citation(s) in RCA: 54] [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: 03/22/2013] [Accepted: 07/30/2013] [Indexed: 01/24/2023] Open
Abstract
The monosaccharide N-acetylglucosamine (GlcNAc) is a major component of microbial cell walls and is ubiquitous in the environment. GlcNAc stimulates developmental pathways in the fungal pathogen Candida albicans, which is a commensal organism that colonizes the mammalian gut and causes disease in the setting of host immunodeficiency. Here we investigate GlcNAc signaling in thermally dimorphic human fungal pathogens, a group of fungi that are highly evolutionarily diverged from C. albicans and cause disease even in healthy individuals. These soil organisms grow as polarized, multicellular hyphal filaments that transition into a unicellular, pathogenic yeast form when inhaled by a human host. Temperature is the primary environmental cue that promotes reversible cellular differentiation into either yeast or filaments; however, a shift to a lower temperature in vitro induces filamentous growth in an inefficient and asynchronous manner. We found GlcNAc to be a potent and specific inducer of the yeast-to-filament transition in two thermally dimorphic fungi, Histoplasma capsulatum and Blastomyces dermatitidis. In addition to increasing the rate of filamentous growth, micromolar concentrations of GlcNAc induced a robust morphological transition of H. capsulatum after temperature shift that was independent of GlcNAc catabolism, indicating that fungal cells sense GlcNAc to promote filamentation. Whole-genome expression profiling to identify candidate genes involved in establishing the filamentous growth program uncovered two genes encoding GlcNAc transporters, NGT1 and NGT2, that were necessary for H. capsulatum cells to robustly filament in response to GlcNAc. Unexpectedly, NGT1 and NGT2 were important for efficient H. capsulatum yeast-to-filament conversion in standard glucose medium, suggesting that Ngt1 and Ngt2 monitor endogenous levels of GlcNAc to control multicellular filamentous growth in response to temperature. Overall, our work indicates that GlcNAc functions as a highly conserved cue of morphogenesis in fungi, which further enhances the significance of this ubiquitous sugar in cellular signaling in eukaryotes.
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Affiliation(s)
- Sarah A. Gilmore
- Department of Microbiology and Immunology and the Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, California, United States of America
| | - Shamoon Naseem
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, New York, United States of America
| | - James B. Konopka
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, New York, United States of America
| | - Anita Sil
- Department of Microbiology and Immunology and the Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, California, United States of America
- * E-mail:
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36
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Franck WL, Gokce E, Oh Y, Muddiman DC, Dean RA. Temporal analysis of the magnaporthe oryzae proteome during conidial germination and cyclic AMP (cAMP)-mediated appressorium formation. Mol Cell Proteomics 2013; 12:2249-65. [PMID: 23665591 PMCID: PMC3734583 DOI: 10.1074/mcp.m112.025874] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2012] [Revised: 04/09/2013] [Indexed: 11/06/2022] Open
Abstract
Rice blast disease caused by Magnaporthe oryzae is one of the most serious threats to global rice production. During the earliest stages of rice infection, M. oryzae conidia germinate on the leaf surface and form a specialized infection structure termed the appressorium. The development of the appressorium represents the first critical stage of infectious development. A total of 3200 unique proteins were identified by nanoLC-MS/MS in a temporal study of conidial germination and cAMP-induced appressorium formation in M. oryzae. Using spectral counting based label free quantification, observed changes in relative protein abundance during the developmental process revealed changes in the cell wall biosynthetic machinery, transport functions, and production of extracellular proteins in developing appressoria. One hundred and sixty-six up-regulated and 208 down-regulated proteins were identified in response to cAMP treatment. Proteomic analysis of a cAMP-dependent protein kinase A mutant that is compromised in the ability to form appressoria identified proteins whose developmental regulation is dependent on cAMP signaling. Selected reaction monitoring was used for absolute quantification of four regulated proteins to validate the global proteomics data and confirmed the germination or appressorium specific regulation of these proteins. Finally, a comparison of the proteome and transcriptome was performed and revealed little correlation between transcript and protein regulation. A subset of regulated proteins were identified whose transcripts show similar regulation patterns and include many of the most strongly regulated proteins indicating a central role in appressorium formation. A temporal quantitative RT-PCR analysis confirmed a strong correlation between transcript and protein abundance for some but not all genes. Collectively, the data presented here provide the first comprehensive view of the M. oryzae proteome during early infection-related development and highlight biological processes important for pathogenicity.
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Affiliation(s)
| | - Emine Gokce
- §W.M. Keck Fourier Transform-ICR Mass Spectrometry Laboratory, Department of Chemistry, North Carolina State University, Raleigh, North Carolina, 27606
| | - Yeonyee Oh
- From the ‡Center for Integrated Fungal Research
| | - David C. Muddiman
- §W.M. Keck Fourier Transform-ICR Mass Spectrometry Laboratory, Department of Chemistry, North Carolina State University, Raleigh, North Carolina, 27606
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Collins C, Keane TM, Turner DJ, O'Keeffe G, Fitzpatrick DA, Doyle S. Genomic and proteomic dissection of the ubiquitous plant pathogen, Armillaria mellea: toward a new infection model system. J Proteome Res 2013; 12:2552-70. [PMID: 23656496 PMCID: PMC3679558 DOI: 10.1021/pr301131t] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
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Armillaria mellea is a major plant
pathogen. Yet, no large-scale “-omics” data are available
to enable new studies, and limited experimental models are available
to investigate basidiomycete pathogenicity. Here we reveal that the A. mellea genome comprises 58.35 Mb, contains 14473 gene
models, of average length 1575 bp (4.72 introns/gene). Tandem mass
spectrometry identified 921 mycelial (n = 629 unique)
and secreted (n = 183 unique) proteins. Almost 100
mycelial proteins were either species-specific or previously unidentified
at the protein level. A number of proteins (n = 111)
was detected in both mycelia and culture supernatant extracts. Signal
sequence occurrence was 4-fold greater for secreted (50.2%) compared
to mycelial (12%) proteins. Analyses revealed a rich reservoir of
carbohydrate degrading enzymes, laccases, and lignin peroxidases in
the A. mellea proteome, reminiscent of both basidiomycete
and ascomycete glycodegradative arsenals. We discovered that A. mellea exhibits a specific killing effect against Candida albicans during coculture. Proteomic investigation
of this interaction revealed the unique expression of defensive and
potentially offensive A. mellea proteins (n = 30). Overall, our data reveal new insights into the
origin of basidiomycete virulence and we present a new model system
for further studies aimed at deciphering fungal pathogenic mechanisms.
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Affiliation(s)
- Cassandra Collins
- Department of Biology, National University of Ireland Maynooth, Maynooth, Co Kildare, Ireland
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Rao KH, Ghosh S, Natarajan K, Datta A. N-acetylglucosamine kinase, HXK1 is involved in morphogenetic transition and metabolic gene expression in Candida albicans. PLoS One 2013; 8:e53638. [PMID: 23341961 PMCID: PMC3544915 DOI: 10.1371/journal.pone.0053638] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Accepted: 12/03/2012] [Indexed: 12/12/2022] Open
Abstract
Candida albicans, a common fungal pathogen which diverged from the baker's yeast Saccharomyces cerevisiae has the unique ability to utilise N-acetylglucosamine, an amino sugar and exhibits phenotypic differences. It has acquired intricate regulatory mechanisms at different levels in accordance with its life style. N-acetylglucosamine kinase, a component of the N-acetylglucosamine catabolic cascade is an understudied gene since Saccharomyces cerevisiae lacks it. We report HXK1 to act as both positive and negative regulator of transcription of genes involved in maintaining cellular homeostasis. It is involved in repression of hyphal specific genes in addition to metabolic genes. Its regulation of filamentation and GlcNAc metabolism is independent of the known classical regulators like EFG1, CPH1, RAS1, TPK2 or TUP1. Moreover, Hxk1-GFP is localised to cytoplasm, nucleus and mitochondria in a condition specific manner. By employing two-step affinity purification, we report the interaction of HXK1 with SIR2 under filamentation inducing conditions. Our work highlights a novel regulatory mechanism involved in filamentation repression and attempts to decipher the GlcNAc catabolic regulatory cascade in eukaryotes.
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Affiliation(s)
| | - Swagata Ghosh
- National Institute of Plant Genome Research, New Delhi, India
| | - Krishnamurthy Natarajan
- The Laboratory of Eukaryotic Gene Expression, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Asis Datta
- National Institute of Plant Genome Research, New Delhi, India
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Robledo-Briones M, Ruiz-Herrera J. Regulation of genes involved in cell wall synthesis and structure during Ustilago maydis dimorphism. FEMS Yeast Res 2012; 13:74-84. [PMID: 23167842 DOI: 10.1111/1567-1364.12011] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Revised: 08/06/2012] [Accepted: 10/05/2012] [Indexed: 11/30/2022] Open
Abstract
The cell wall is the structure that provides the shape to fungal cells and protects them from the difference in osmotic pressure existing between the cytosol and the external medium. Accordingly, changes in structure and composition of the fungal wall must occur during cell differentiation, including the dimorphic transition of fungi. We analyzed, by use of microarrays, the transcriptional regulation of the 639 genes identified to be involved in cell wall synthesis and structure plus the secretome of the Basidiomycota species Ustilago maydis during its dimorphic transition induced by a change in pH. Of these, 189 were differentially expressed during the process, and using as control two monomorphic mutants, one yeast like and the other mycelium constitutive, 66 genes specific of dimorphism were identified. Most of these genes were up-regulated in the mycelial phase. These included CHS genes, genes involved in β-1,6-glucan synthesis, N-glycosylation, and proteins containing a residue of glycosylphosphatidylinositol, and a number of genes from the secretome. The possible significance of these data on cell wall plasticity is discussed.
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Affiliation(s)
- Mariana Robledo-Briones
- Departamento de Ingeniería Genética, Unidad Irapuato, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Irapuato, Guanajuato, México
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Abstract
N-acetylglucosamine (GlcNAc) has long been known to play important roles in cell surface structure. Recent studies are now revealing new functions for GlcNAc in cell signaling. Exposure to GlcNAc regulates virulence functions in the human fungal pathogen Candida albicans and in pathogenic bacteria. These signaling pathways sense exogenous GlcNAc and are distinct from the O-GlcNAc signaling pathways in mammalian cells in which increased levels of intracellular GlcNAc synthesis leads to post-translational modification of proteins by attachment of O-GlcNAc. The novel roles of GlcNAc in cell signaling will be the subject of this mini-review.
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41
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Jeong KH, Nguyen V, Kim JH. Human milk oligosaccharides: the novel modulator of intestinal microbiota. BMB Rep 2012; 45:433-41. [DOI: 10.5483/bmbrep.2012.45.8.168] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
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42
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Bergfeld AK, Pearce OMT, Diaz SL, Pham T, Varki A. Metabolism of vertebrate amino sugars with N-glycolyl groups: elucidating the intracellular fate of the non-human sialic acid N-glycolylneuraminic acid. J Biol Chem 2012; 287:28865-81. [PMID: 22692205 DOI: 10.1074/jbc.m112.363549] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The two major mammalian sialic acids are N-acetylneuraminic acid and N-glycolylneuraminic acid (Neu5Gc). The only known biosynthetic pathway generating Neu5Gc is the conversion of CMP-N-acetylneuraminic acid into CMP-Neu5Gc, which is catalyzed by the CMP-Neu5Ac hydroxylase enzyme. Given the irreversible nature of this reaction, there must be pathways for elimination or degradation of Neu5Gc, which would allow animal cells to adjust Neu5Gc levels to their needs. Although humans are incapable of synthesizing Neu5Gc due to an inactivated CMAH gene, exogenous Neu5Gc from dietary sources can be metabolically incorporated into tissues in the face of an anti-Neu5Gc antibody response. However, the metabolic turnover of Neu5Gc, which apparently prevents human cells from continued accumulation of this immunoreactive sialic acid, has not yet been elucidated. In this study, we show that pre-loaded Neu5Gc is eliminated from human cells over time, and we propose a conceivable Neu5Gc-degrading pathway based on the well studied metabolism of N-acetylhexosamines. We demonstrate that murine tissue cytosolic extracts harbor the enzymatic machinery to sequentially convert Neu5Gc into N-glycolylmannosamine, N-glycolylglucosamine, and N-glycolylglucosamine 6-phosphate, whereupon irreversible de-N-glycolylation of the latter results in the ubiquitous metabolites glycolate and glucosamine 6-phosphate. We substantiate this finding by demonstrating activity of recombinant human enzymes in vitro and by studying the fate of radiolabeled pathway intermediates in cultured human cells, suggesting that this pathway likely occurs in vivo. Finally, we demonstrate that the proposed degradative pathway is partially reversible, showing that N-glycolylmannosamine and N-glycolylglucosamine (but not glycolate) can serve as precursors for biosynthesis of endogenous Neu5Gc.
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Affiliation(s)
- Anne K Bergfeld
- Department of Medicine, Glycobiology Research and Training Center, University of California San Diego, La Jolla, California 92093-0687, USA
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Abstract
The human commensal fungus Candida albicans can cause not only superficial infections, but also life-threatening disease in immunocompromised individuals. C. albicans can grow in several morphological forms. The ability to switch between different phenotypic forms has been thought to contribute to its virulence. The yeast-filamentous growth transition and white-opaque switching represent two typical morphological switching systems, which have been intensively studied in C. albicans. The interplay between environmental factors and genes determines the morphology of C. albicans. This review focuses on the regulation of phenotypic changes in this pathogenic organism by external environmental cues and internal genes.
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Affiliation(s)
- Guanghua Huang
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences Beijing, China.
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Konopka JB. N-acetylglucosamine (GlcNAc) functions in cell signaling. SCIENTIFICA 2012; 2012:489208. [PMID: 23350039 PMCID: PMC3551598 DOI: 10.6064/2012/489208] [Citation(s) in RCA: 115] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Accepted: 10/23/2012] [Indexed: 05/21/2023]
Abstract
The amino sugar N-acetylglucosamine (GlcNAc) is well known for the important structural roles that it plays at the cell surface. It is a key component of bacterial cell wall peptidoglycan, fungal cell wall chitin, and the extracellular matrix of animal cells. Interestingly, recent studies have also identified new roles for GlcNAc in cell signaling. For example, GlcNAc stimulates the human fungal pathogen Candida albicans to undergo changes in morphogenesis and expression of virulence genes. Pathogenic E. coli respond to GlcNAc by altering the expression of fimbriae and CURLI fibers that promote biofilm formation and GlcNAc stimulates soil bacteria to undergo changes in morphogenesis and production of antibiotics. Studies with animal cells have revealed that GlcNAc influences cell signaling through the post-translational modification of proteins by glycosylation. O-linked attachment of GlcNAc to Ser and Thr residues regulates a variety of intracellular proteins, including transcription factors such as NFκB, c-myc and p53. In addition, the specificity of Notch family receptors for different ligands is altered by GlcNAc attachment to fucose residues in the extracellular domain. GlcNAc also impacts signal transduction by altering the degree of branching of N-linked glycans, which influences cell surface signaling proteins. These emerging roles of GlcNAc as an activator and mediator of cellular signaling in fungi, animals, and bacteria will be the focus of this review.
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Affiliation(s)
- James B. Konopka
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, NY 11794-5222, USA
- *James B. Konopka:
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Kamerewerd J, Zadra I, Kürnsteiner H, Kück U. PcchiB1, encoding a class V chitinase, is affected by PcVelA and PcLaeA, and is responsible for cell wall integrity in Penicillium chrysogenum. MICROBIOLOGY-SGM 2011; 157:3036-3048. [PMID: 21816879 DOI: 10.1099/mic.0.051896-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Penicillin production in Penicillium chrysogenum is controlled by PcVelA and PcLaeA, two components of the regulatory velvet-like complex. Comparative microarray analysis with mutants lacking PcVelA or PcLaeA revealed a set of 62 common genes affected by the loss of both components. A downregulated gene in both knockout strains is PcchiB1, potentially encoding a class V chitinase. Under nutrient-depleted conditions, transcript levels of PcchiB1 are strongly upregulated, and the gene product contributes to more than 50 % of extracellular chitinase activity. Functional characterization by generating PcchiB1-disruption strains revealed that PcChiB1 is responsible for cell wall integrity and pellet formation in P. chrysogenum. Further, fluorescence microscopy with a DsRed-labelled chitinase suggests a cell wall association of the protein. An unexpected phenotype occurred when knockout strains were grown on media containing N-acetylglucosamine as the sole C and N source, where, in contrast to the recipient, a penicillin producer strain, the mutants and an ancestral strain show distinct mycelial growth. We discuss the relevance of this class V chitinase for morphology in an industrially important fungus.
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Affiliation(s)
- Jens Kamerewerd
- Christian Doppler Laboratory for 'Fungal Biotechnology', Lehrstuhl für Allgemeine und Molekulare Botanik, Ruhr-Universität Bochum, Universitätsstraße 150, 44780 Bochum, Germany
| | - Ivo Zadra
- Anti Infectives Microbiology, Sandoz GmbH, Biochemiestraße 10, 6250 Kundl, Austria
| | - Hubert Kürnsteiner
- Anti Infectives Microbiology, Sandoz GmbH, Biochemiestraße 10, 6250 Kundl, Austria
| | - Ulrich Kück
- Christian Doppler Laboratory for 'Fungal Biotechnology', Lehrstuhl für Allgemeine und Molekulare Botanik, Ruhr-Universität Bochum, Universitätsstraße 150, 44780 Bochum, Germany
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Naseem S, Gunasekera A, Araya E, Konopka JB. N-acetylglucosamine (GlcNAc) induction of hyphal morphogenesis and transcriptional responses in Candida albicans are not dependent on its metabolism. J Biol Chem 2011; 286:28671-28680. [PMID: 21700702 DOI: 10.1074/jbc.m111.249854] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
N-acetylglucosamine (GlcNAc) stimulates important signaling pathways in a wide range of organisms. In the human fungal pathogen Candida albicans, GlcNAc stimulates hyphal cell morphogenesis, virulence genes, and the genes needed to catabolize GlcNAc. Previous studies on the GlcNAc transporter (NGT1) indicated that GlcNAc has to be internalized to induce signaling. Therefore, the role of GlcNAc catabolism was examined by deleting the genes required to phosphorylate, deacetylate, and deaminate GlcNAc to convert it to fructose-6-PO(4) (HXK1, NAG1, and DAC1). As expected, the mutants failed to utilize GlcNAc. Surprisingly, GlcNAc inhibited the growth of the nag1Δ and dac1Δ mutants in the presence of other sugars, suggesting that excess GlcNAc-6-PO(4) is deleterious. Interestingly, both hxk1Δ and an hxk1Δ nag1Δ dac1Δ triple mutant could be efficiently stimulated by GlcNAc to form hyphae. These mutants could also be stimulated to express GlcNAc-regulated genes. Because GlcNAc must be phosphorylated by Hxk1 to be catabolized, and also for it to enter the anabolic pathways that form chitin, N-linked glycosylation, and glycosylphosphatidylinositol anchors, the mutant phenotypes indicate that GlcNAc metabolism is not needed to induce signaling in C. albicans. Thus, these studies in C. albicans reveal a novel role for GlcNAc in cell signaling that may also regulate critical pathways in other organisms.
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Affiliation(s)
- Shamoon Naseem
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, New York 11794-5222
| | - Angelo Gunasekera
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, New York 11794-5222
| | - Esteban Araya
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, New York 11794-5222
| | - James B Konopka
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, New York 11794-5222.
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Identification of GIG1, a GlcNAc-induced gene in Candida albicans needed for normal sensitivity to the chitin synthase inhibitor nikkomycin Z. EUKARYOTIC CELL 2010; 9:1476-83. [PMID: 20675577 DOI: 10.1128/ec.00178-10] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The amino sugar N-acetylglucosamine (GlcNAc) is known to be an important structural component of cells from bacteria to humans, but its roles in cell signaling are less well understood. GlcNAc induces two pathways in the human fungal pathogen Candida albicans. One activates cyclic AMP (cAMP) signaling, which stimulates the formation of hyphal cells and the expression of virulence genes, and the other pathway induces genes needed to catabolize GlcNAc. Microarray analysis of gene expression was carried out under four different conditions in order to characterize the transcriptional changes induced by GlcNAc. The most highly induced genes include those that encode a GlcNAc transporter (NGT1) and the GlcNAc catabolic enzymes (HXK1, DAC1, and NAG1). GlcNAc also activated most of the genes whose expression is increased when cells are triggered with other stimuli to form hyphae. Surprisingly, GlcNAc also induced a subset of genes that are regulated by galactose (GAL1, GAL7, and GAL10), which may be due to cross talk between signaling pathways. A novel GlcNAc-induced gene, GIG1, which is not essential for GlcNAc catabolism or the induction of hyphae, was identified. However, a Gig1-green fluorescent protein (GFP) fusion protein was specifically induced by GlcNAc, and not by other sugars. Gig1-GFP localized to the cytoplasm, where GlcNAc metabolism occurs. Significantly, a gig1Δ mutant displayed increased resistance to nikkomycin Z, which inhibits chitin synthase from converting UDP-GlcNAc into cell wall chitin. Gig1 is highly conserved in fungi, especially those that contain GlcNAc catabolic genes. These results implicate Gig1 in GlcNAc metabolism.
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Targeted metabolic labeling of yeast N-glycans with unnatural sugars. Proc Natl Acad Sci U S A 2010; 107:3988-93. [PMID: 20142501 DOI: 10.1073/pnas.0911247107] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Metabolic labeling of glycans with synthetic sugar analogs has emerged as an attractive means for introducing nonnatural chemical functionality into glycoproteins. However, the complexities of glycan biosynthesis prevent the installation of nonnatural moieties at defined, predictable locations within glycoproteins at high levels of incorporation. Here, we demonstrate that the conserved N-acetyglucosamine (GlcNAc) residues within chitobiose cores of N-glycans in the model organism Saccharomyces cerevisiae can be specifically targeted for metabolic replacement by unnatural sugars. We introduced an exogenous GlcNAc salvage pathway into yeast, allowing cells to metabolize GlcNAc provided as a supplement to the culture medium. We then rendered the yeast auxotrophic for production of the donor nucleotide-sugar uridine-diphosphate-GlcNAc (UDP-GlcNAc) by deletion of the essential gene GNA1. We demonstrate that gna1Delta strains require a GlcNAc supplement and that expression plasmids containing both exogenous components of the salvage pathway, GlcNAc transporter NGT1 from Candida albicans and GlcNAc kinase NAGK from Homo sapiens, are required for rescue in this context. Further, we show that cells successfully incorporate synthetic GlcNAc analogs N-azidoacetyglucosamine (GlcNAz) and N-(4-pentynoyl)-glucosamine (GlcNAl) into cell-surface glycans and secreted glycoproteins. To verify incorporation of the nonnatural sugars at N-glycan core positions, endoglycosidase H (endoH)-digested peptides from a purified secretory glycoprotein, Ygp1, were analyzed by mass spectrometry. Multiple Ygp1 N-glycosylation sites bearing GlcNAc, isotopically labeled GlcNAc, or GlcNAz were identified; these modifications were dependent on the supplement added to the culture medium. This system enables the production of glycoproteins that are functionalized for specific chemical modifications at their glycosylation sites.
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Chitinases are essential for sexual development but not vegetative growth in Cryptococcus neoformans. EUKARYOTIC CELL 2009; 8:1692-705. [PMID: 19734369 DOI: 10.1128/ec.00227-09] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Cryptococcus neoformans is an opportunistic pathogen that mainly infects immunocompromised individuals. The fungal cell wall of C. neoformans is an excellent target for antifungal therapies since it is an essential organelle that provides cell structure and integrity. Importantly, it is needed for localization or attachment of known virulence factors, including melanin, phospholipase, and the polysaccharide capsule. The polysaccharide fraction of the cryptococcal cell wall is a complex structure composed of chitin, chitosan, and glucans. Chitin is an indispensable component of many fungal cell walls that contributes significantly to cell wall strength and integrity. Fungal cell walls are very dynamic, constantly changing during cell division and morphogenesis. Hydrolytic enzymes, such as chitinases, have been implicated in the maintenance of cell wall plasticity and separation of the mother and daughter cells at the bud neck during vegetative growth in yeast. In C. neoformans we identified four predicted endochitinases, CHI2, CHI21, CHI22, and CHI4, and a predicted exochitinase, hexosaminidase, HEX1. Enzymatic analysis indicated that Chi2, Chi22, and Hex1 actively degraded chitinoligomeric substrates. Chi2 and Hex1 activity was associated mostly with the cellular fraction, and Chi22 activity was more prominent in the supernatant. The enzymatic activity of Hex1 increased when grown in media containing only N-acetylglucosamine as a carbon source, suggesting that its activity may be inducible by chitin degradation products. Using a quadruple endochitinase deletion strain, we determined that the endochitinases do not affect the growth or morphology of C. neoformans during asexual reproduction. However, mating assays indicated that Chi2, Chi21, and Chi4 are each involved in sexual reproduction. In summary, the endochitinases were found to be dispensable for routine vegetative growth but not sexual reproduction.
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Biswas S, Van Dijck P, Datta A. Environmental sensing and signal transduction pathways regulating morphopathogenic determinants of Candida albicans. Microbiol Mol Biol Rev 2007; 71:348-76. [PMID: 17554048 PMCID: PMC1899878 DOI: 10.1128/mmbr.00009-06] [Citation(s) in RCA: 396] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Candida albicans is an opportunistic fungal pathogen that is found in the normal gastrointestinal flora of most healthy humans. However, under certain environmental conditions, it can become a life-threatening pathogen. The shift from commensal organism to pathogen is often correlated with the capacity to undergo morphogenesis. Indeed, under certain conditions, including growth at ambient temperature, the presence of serum or N-acetylglucosamine, neutral pH, and nutrient starvation, C. albicans can undergo reversible transitions from the yeast form to the mycelial form. This morphological plasticity reflects the interplay of various signal transduction pathways, either stimulating or repressing hyphal formation. In this review, we provide an overview of the different sensing and signaling pathways involved in the morphogenesis and pathogenesis of C. albicans. Where appropriate, we compare the analogous pathways/genes in Saccharomyces cerevisiae in an attempt to highlight the evolution of the different components of the two organisms. The downstream components of these pathways, some of which may be interesting antifungal targets, are also discussed.
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Affiliation(s)
- Subhrajit Biswas
- National Centre for Plant Genome Research, New Delhi 110 067, India
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