1
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Feng Y, Li N, Ren Y. GNPNAT1 Predicts Poor Prognosis and Cancer Development in Non-Small Cell Lung Cancer. Cancer Manag Res 2022; 14:2419-2428. [PMID: 35975106 PMCID: PMC9375989 DOI: 10.2147/cmar.s367857] [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: 03/24/2022] [Accepted: 08/03/2022] [Indexed: 11/24/2022] Open
Abstract
Background Glucosamine-phosphate N-acetyltransferase 1 (GNPNAT1) is a key enzyme in the biosynthetic pathway of uridine diphosphate-N-acetylglucosamine and is upregulated in multiple malignancies. However, its function in cancer biology remains unclear. Methods Using TCGA dataset, this study analysed GNPNAT1 expression in non-small cell lung cancer (NSCLC) and assessed the correlation between GNPNAT1 and NSCLC patient prognosis. MTT and transwell assays were performed to determine the effect of GNPNAT1 on the growth and metastatic ability of lung cancer cells. GNPNAT1 expression was detected using immunohistochemistry in 78 NSCLC patients, and we analysed the correlation among clinicopathological parameters, overall survival (OS) and GNPNAT1 levels. Transcription factors that potentially regulate GNPNAT1 were explored using database analysis. RNF2 expression was verified using immunohistochemistry in NSCLC tissues. Results The results indicated that GNPNAT1 was upregulated in NSCLC, and patients with high GNPNAT1 levels had a poor prognosis. GNPNAT1 overexpression promoted the proliferative and metastatic ability of lung cancer cells, whereas GNPNAT1 knockdown showed the opposite effect. GNPNAT1 expression was upregulated in NSCLC tissues compared to matched normal tissues as assessed by immunohistochemistry. Moreover, GNPNAT1 levels were positively correlated with histological type and pathological stage. The negative correlation between GNPNAT1 levels and OS was confirmed in 78 NSCLC patients. Aberrant RNF2 partly contributed to the upregulation of GNPNAT1 expression in NSCLC. Conclusion These findings suggested that GNPNAT1 was upregulated and played an important role in NSCLC. GNPNAT1 is expected to represent an effective prognostic biomarker for NSCLC patients.
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Affiliation(s)
- Yong Feng
- Department of Thoracic Surgery, Shenyang Chest Hospital, the Tenth People's Hospital of Shenyang, Shenyang, People's Republic of China
| | - Na Li
- Department of Thoracic Surgery, Shenyang Chest Hospital, the Tenth People's Hospital of Shenyang, Shenyang, People's Republic of China
| | - Yi Ren
- Department of Thoracic Surgery, Shenyang Chest Hospital, the Tenth People's Hospital of Shenyang, Shenyang, People's Republic of China
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2
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Abdulghani M, Iram R, Chidrawar P, Bhosle K, Kazi R, Patil R, Kharat K, Zore G. Proteomic profile of Candida albicans biofilm. J Proteomics 2022; 265:104661. [PMID: 35728770 DOI: 10.1016/j.jprot.2022.104661] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 04/06/2022] [Accepted: 06/08/2022] [Indexed: 11/25/2022]
Abstract
Candida albicans biofilms are characterized by structural and cellular heterogeneity that confers antifungal resistance and immune evasion. Despite this, biofilm formation remains poorly understood. In this study, we used proteomic analysis to understand biofilm formation in C. albicans related to morphophysiological and architectural features. LC-MS/MS analysis revealed that 64 proteins were significantly modulated, of which 31 were upregulated and 33 were downregulated. The results indicate that metabolism (25 proteins), gene expression (13 proteins), stress response (7 proteins), and cell wall (5 proteins) composition are modulated. The rate of oxidative phosphorylation (OxPhos) and biosynthesis of UDP-N-acetylglucosamine, vitamin B6, and thiamine increased, while the rate of methionine biosynthesis decreased. There was a significant modification of the cell wall architecture due to higher levels of Sun41, Pir1 and Csh1 and increased glycosylation of proteins. It was observed that C. albicans induces hyphal growth by upregulating the expression of genes involved in cAMP-PKA and MAPK pathways. This study is significant in that it suggests an increase in OxPhos and alteration of cell wall architecture that could be contributing to the recalcitrance of C. albicans cells growing in biofilms. Nevertheless, a deeper investigation is needed to explore it further. SIGNIFICANCE: Candida sps is included in the list of pathogens with potential drug resistance threat due to the increased frequency especially colonization of medical devices, and tissues among the patients, in recent years. Significance of our study is that we are reporting traits like modulation in cell wall composition, amino acid and vitamin biosynthesis and importantly energy generation (OxPhos) etc. These traits could be conferring antifungal resistance, host immune evasion etc. and thus survival, in addition to facilitating biofilm formation. These findings are expected to prime the further studies on devising potent strategy against biofilm growth among the patients.
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Affiliation(s)
- Mazen Abdulghani
- School of Life Sciences, Swami Ramanand Teerth Marathwada University, Nanded 431606, MS, India
| | - Rasiqua Iram
- School of Life Sciences, Swami Ramanand Teerth Marathwada University, Nanded 431606, MS, India
| | - Priti Chidrawar
- School of Life Sciences, Swami Ramanand Teerth Marathwada University, Nanded 431606, MS, India
| | - Kajal Bhosle
- School of Life Sciences, Swami Ramanand Teerth Marathwada University, Nanded 431606, MS, India
| | - Rubina Kazi
- Division of Biochemical Sciences, CSIR-NCL, Pune 8, MS, India
| | - Rajendra Patil
- Department of Biotechnology, Savitribai Phule Pune University, Ganeshkhind, Pune 411007, MS, India
| | - Kiran Kharat
- Department of Biotechnology, Deogiri College, Aurangabad, MS, India
| | - Gajanan Zore
- School of Life Sciences, Swami Ramanand Teerth Marathwada University, Nanded 431606, MS, India.
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3
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Glucosamine-6-phosphate N-acetyltransferase gene silencing by parental RNA interference in rice leaf folder, Cnaphalocrocis medinalis (Lepidoptera: Pyralidae). Sci Rep 2022; 12:2141. [PMID: 35136178 PMCID: PMC8825807 DOI: 10.1038/s41598-022-06193-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 12/21/2021] [Indexed: 11/26/2022] Open
Abstract
Parental RNAi (pRNAi) is a response of RNA interference in which treated insect pests progenies showed a gene silencing phenotypes. pRNAi of CmGNA gene has been studied in Cnaphalocrocis medinalis via injection. Our results showed significant reduction in ovulation per female that was 26% and 35.26% in G1 and G2 generations, respectively. Significant reduction of hatched eggs per female were observed 23.53% and 45.26% as compared to control in G1–G2 generations, respectively. We also observed the significant variation in the sex ratio between female (40% and 53%) in G1–G2 generations, and in male (65%) in G1 generation as compared to control. Our results also demonstrated the significant larval mortality (63% and 55%) and pupal mortality (55% and 41%), and significant reduction of mRNA expression level in G1 and G2 generations. Our findings have confirmed that effectiveness of pRNAi induced silencing on the CmGNA target gene in G1–G2 generations of C. medinalis. These results suggested the potential role of pRNAi in insect pest resistance management strategies.
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4
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Zhang S, Zhang H, Li H, Guo J, Wang J, Zhang L. Potential role of glucosamine-phosphate N-acetyltransferase 1 in the development of lung adenocarcinoma. Aging (Albany NY) 2021; 13:7430-7453. [PMID: 33686019 PMCID: PMC7993716 DOI: 10.18632/aging.202604] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 12/23/2020] [Indexed: 12/18/2022]
Abstract
Glucosamine-phosphate N-acetyltransferase 1 (GNPNAT1) is a key enzyme associated with glucose metabolism and uridine diphosphate-N-acetylglucosamine biosynthesis. Abnormal GNPNAT1 expression might be associated with carcinogenesis. We analyzed multiple lung adenocarcinoma (LUAD) gene expression databases and verified GNPNAT1 higher expression in LUAD tumor tissues than in normal tissues. Moreover, we analyzed the survival relationship between LUAD patients’ clinical status and GNPNAT1 expression, and found higher GNPNAT1 expression in LUAD patients with unfavorable prognosis. We built GNPNAT1 gene co-expression networks and further annotated the co-expressed genes’ Gene Ontology (GO) terms, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, and various associated regulatory factors. These co-expression genes’ functional networks mainly participate in chromosome segregation, RNA metabolic process, and RNA transport. We analyzed GNPNAT1 genetic alterations and co-occurrence networks, and the functional networks of these genes showed that GNPNAT1 participates in multiple steps of cell cycle transition and in the development of some cancers. We assessed the correlation between GNPNAT1 expression and cancer immune infiltrates and showed that GNPNAT1 expression is correlated with several immune cells, chemokines, and immunomodulators in LUAD. We found that GNPNAT1 correlates with LUAD development and prognosis, laying a foundation for further research, especially in immunotherapy.
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Affiliation(s)
- Shengqiang Zhang
- Department of Thoracic Surgery, The Second Affiliated Hospital of Harbin Medical University, Harbin 150086, Heilongjiang, People's Republic of China
| | - Hongyan Zhang
- Department of Physiology and Neurobiology, Mudanjiang Medical University, Mudanjiang 157000, Heilongjiang, People's Republic of China
| | - Huawei Li
- Department of Thoracic Surgery, The Second Affiliated Hospital of Harbin Medical University, Harbin 150086, Heilongjiang, People's Republic of China
| | - Jida Guo
- Department of Thoracic Surgery, The Second Affiliated Hospital of Harbin Medical University, Harbin 150086, Heilongjiang, People's Republic of China
| | - Jun Wang
- Department of Thoracic Surgery, The Second Affiliated Hospital of Harbin Medical University, Harbin 150086, Heilongjiang, People's Republic of China
| | - Linyou Zhang
- Department of Thoracic Surgery, The Second Affiliated Hospital of Harbin Medical University, Harbin 150086, Heilongjiang, People's Republic of China
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5
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Lockhart DEA, Stanley M, Raimi OG, Robinson DA, Boldovjakova D, Squair DR, Ferenbach AT, Fang W, van Aalten DMF. Targeting a critical step in fungal hexosamine biosynthesis. J Biol Chem 2020; 295:8678-8691. [PMID: 32341126 PMCID: PMC7324522 DOI: 10.1074/jbc.ra120.012985] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 04/22/2020] [Indexed: 01/06/2023] Open
Abstract
Aspergillus fumigatus is a human opportunistic fungal pathogen whose cell wall protects it from the extracellular environment including host defenses. Chitin, an essential component of the fungal cell wall, is synthesized from UDP-GlcNAc produced in the hexosamine biosynthetic pathway. As this pathway is critical for fungal cell wall integrity, the hexosamine biosynthesis enzymes represent potential targets of antifungal drugs. Here, we provide genetic and chemical evidence that glucosamine 6-phosphate N-acetyltransferase (Gna1), a key enzyme in this pathway, is an exploitable antifungal drug target. GNA1 deletion resulted in loss of fungal viability and disruption of the cell wall, phenotypes that could be rescued by exogenous GlcNAc, the product of the Gna1 enzyme. In a murine model of aspergillosis, the Δgna1 mutant strain exhibited attenuated virulence. Using a fragment-based approach, we discovered a small heterocyclic scaffold that binds proximal to the Gna1 active site and can be optimized to a selective submicromolar binder. Taken together, we have provided genetic, structural, and chemical evidence that Gna1 is an antifungal target in A. fumigatus.
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Affiliation(s)
- Deborah E A Lockhart
- School of Life Sciences, University of Dundee, Dundee, United Kingdom; Institute of Medical Sciences, Foresterhill, University of Aberdeen, Aberdeen, United Kingdom.
| | - Mathew Stanley
- School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Olawale G Raimi
- School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - David A Robinson
- Drug Discovery Unit, Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Dominika Boldovjakova
- Institute of Medical Sciences, Foresterhill, University of Aberdeen, Aberdeen, United Kingdom
| | - Daniel R Squair
- School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | | | - Wenxia Fang
- School of Life Sciences, University of Dundee, Dundee, United Kingdom
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6
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Chen X, Zhang Z, Chen Z, Li Y, Su S, Sun S. Potential Antifungal Targets Based on Glucose Metabolism Pathways of Candida albicans. Front Microbiol 2020; 11:296. [PMID: 32256459 PMCID: PMC7093590 DOI: 10.3389/fmicb.2020.00296] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 02/10/2020] [Indexed: 01/04/2023] Open
Abstract
In recent years, fungal infections have become a serious health problem. Candida albicans are considered as the fourth most common isolates associated with approximately 40% mortality in bloodstream infections among hospitalized patients. Due to various limitations of classical antifungals used currently, such as limited kinds of drugs, inevitable toxicities, and high price, there is an urgent need to explore new antifungal agents based on novel targets. Generally, nutrient metabolism is involved with fungal virulence, and glucose is one of the important nutrients in C. albicans. C. albicans can obtain and metabolize glucose through a variety of pathways; in theory, many enzymes in these pathways can be potential targets for developing new antifungal agents, and several studies have confirmed that compounds which interfere with alpha-glucosidase, acid trehalase, trehalose-6-phosphate synthase, class II fructose bisphosphate aldolases, and glucosamine-6-phosphate synthase in these pathways do have antifungal activities. In this review, the glucose metabolism pathways in C. albicans, the potential antifungal targets based on these pathways, and some compounds which have antifungal activities by inhibiting several enzymes in these pathways are summarized. We believe that our review will be helpful to the exploration of new antifungal drugs with novel antifungal targets.
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Affiliation(s)
- Xueqi Chen
- Department of Pharmacy, Shandong Provincial Qianfoshan Hospital, Shandong University, Jinan, China
- School of Pharmaceutical Sciences, Shandong University, Jinan, China
| | - Zewen Zhang
- Department of Imaging Medicine and Nuclear Medicine, Qilu Medical College, Shandong University, Jinan, China
| | - Zuozhong Chen
- Department of Pharmacy, Zibo Central Hospital, Zibo, China
| | - Yiman Li
- School of Pharmaceutical Sciences, Shandong University, Jinan, China
| | - Shan Su
- School of Pharmaceutical Sciences, Shandong University, Jinan, China
| | - Shujuan Sun
- Department of Clinical Pharmacy, The First Affiliated Hospital of Shandong First Medical University, Jinan, China
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7
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Genetically Compromising Phospholipid Metabolism Limits Candida albicans' Virulence. Mycopathologia 2019; 184:213-226. [PMID: 30693413 DOI: 10.1007/s11046-019-00320-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Accepted: 01/19/2019] [Indexed: 01/06/2023]
Abstract
Perturbing ergosterol synthesis has been previously shown to reduce the virulence of Candida albicans. We tested the hypothesis that further altering cell membrane composition by limiting phospholipid synthesis or remodeling will have the same effect. To model partial inhibition, C. albicans strains independently harboring heterozygous deletion of four genes that encode for enzymes that mediate phospholipid synthesis or modification were generated. Quantitative PCR determined that heterozygous deletion routinely caused a nearly 50% reduction in the respective gene's transcript abundance. Compensatory increased transcript abundance was only found with the deletion of LRO1, a homolog of phospholipid diacylglycerol acyltransferases. Virulence of the mutants was assayed in a Caenorhabditis elegans host model. Even modestly reduced expression of LRO1, phosphatidylserine synthase (CHO1), and lysophospholipid acyltransferase (LPT1) significantly reduced virulence by 23-38%. Reintroducing a second functional allele, respectively, to all three mutants restored virulence. Heterozygous deletion of SLC1, a homolog of 1-acylglycerol-3-phosphate O-acyltransferases, did not significantly reduce virulence. Electrospray ionization tandem mass spectrometry analysis of phospholipid composition followed by principal component analysis identified comprehensive changes in the LRO1 and CHO1 deletion heterozygotes. Strikingly (p < 0.001), univariate comparisons found that both deletion heterozygotes had 20% more phosphatidylinositol, 75% less lysophosphatidylcholine, and 35% less lysophosphatidylethanolamine compared to wild type. Heterozygous deletion of LPT1 also significantly increased phosphatidylinositol abundance. No growth phenotype, including filamentation, was affected by any mutation. Together, these data predict that even partial pharmacological inhibition of Lro1p, Cho1p, and Lpt1p will limit C. albicans virulence through altering phospholipid composition.
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8
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Skarbek K, Gabriel I, Szweda P, Wojciechowski M, Khan MA, Görke B, Milewski S, Milewska MJ. Synthesis and antimicrobial activity of 6-sulfo-6-deoxy-D-glucosamine and its derivatives. Carbohydr Res 2017. [PMID: 28628891 DOI: 10.1016/j.carres.2017.06.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
6-Sulfo-6-deoxy-D-glucosamine (GlcN6S), 6-sulfo-6-deoxy-D-glucosaminitol (ADGS) and their N-acetyl and methyl ester derivatives have been synthesized and tested as inhibitors of enzymes catalyzing reactions of the UDP-GlcNAc pathway in bacteria and yeasts. GlcN6S and ADGS at micromolar concentrations inhibited glucosamine-6-phosphate (GlcN6P) synthase of microbial origin. The former was also inhibitory towards fungal GlcN6P N-acetyl transferase, but at millimolar concentrations. Both compounds and their N-acetyl derivatives exhibited antimicrobial in vitro activity, with MICs in the 0.125-2.0 mg mL-1 range. Antibacterial but not antifungal activity of GlcN6S was potentiated by D-glucosamine and a synergistic antibacterial effect was observed for combination of ADGP and a dipeptide Nva-FMDP.
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Affiliation(s)
- Kornelia Skarbek
- Department of Organic Chemistry, Gdańsk University of Technology, Gdańsk, Poland
| | - Iwona Gabriel
- Department of Pharmaceutical Technology and Biochemistry, Gdańsk University of Technology, Gdańsk, Poland
| | - Piotr Szweda
- Department of Pharmaceutical Technology and Biochemistry, Gdańsk University of Technology, Gdańsk, Poland
| | - Marek Wojciechowski
- Department of Pharmaceutical Technology and Biochemistry, Gdańsk University of Technology, Gdańsk, Poland
| | - Muna A Khan
- Department of Microbiology, Immunobiology and Genetics, Max F. Perutz Laboratories, University of Vienna, Vienna Biocenter, Vienna, Austria
| | - Boris Görke
- Department of Microbiology, Immunobiology and Genetics, Max F. Perutz Laboratories, University of Vienna, Vienna Biocenter, Vienna, Austria
| | - Sławomir Milewski
- Department of Pharmaceutical Technology and Biochemistry, Gdańsk University of Technology, Gdańsk, Poland.
| | - Maria J Milewska
- Department of Organic Chemistry, Gdańsk University of Technology, Gdańsk, Poland
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9
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Zhao M, Li H, Ma Y, Gong H, Yang S, Fang Q, Hu Z. Nanoparticle abraxane possesses impaired proliferation in A549 cells due to the underexpression of glucosamine 6-phosphate N-acetyltransferase 1 (GNPNAT1/GNA1). Int J Nanomedicine 2017; 12:1685-1697. [PMID: 28280335 PMCID: PMC5338994 DOI: 10.2147/ijn.s129976] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Abraxane (Abr), a US Food and Drug Administration-approved albumin-bound nanoparticle applied for the treatment of non-small-cell lung cancer, has been reported to be more effective than paclitaxel (PTX). To further understand the molecular mechanisms that produce this superior drug efficacy of Abr, a quantitative proteomic approach has been applied to investigate the global protein expression profiles of lung cancer cell A549 treated with Abr and PTX. Only one protein, namely, glucosamine 6-phosphate N-acetyltransferase 1 (GNA1), showed significant differential expression (P<0.05) in the cutoff of 2.0 fold, suggesting that Abr can be used safely as a substitute for PTX. GNA1 is a key enzyme in the biosynthesis of uridine diphosphate-N-acetylglucosamine, which is an important donor substrate for N-linked glycosylation and has several important functions such as embryonic development and growth. Albumin plays a major role in the regulation of this protein. In summary, this study first shows that the superior drug effect of Abr is mainly due to the downregulation of GNA1, which causes proliferative delay and cell adhesion defect. It is also noteworthy that the deficiency of GNA1 might reduce insulin secretion which correlates with type 2 diabetes.
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Affiliation(s)
- Minzhi Zhao
- Chinese Academy of Sciences Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, People's Republic of China
| | - Haiyun Li
- Chinese Academy of Sciences Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, People's Republic of China
| | - Yan Ma
- Chinese Academy of Sciences Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, People's Republic of China
| | - He Gong
- Chinese Academy of Sciences Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, People's Republic of China
| | - Shu Yang
- Chinese Academy of Sciences Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, People's Republic of China
| | - Qiaojun Fang
- Chinese Academy of Sciences Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, People's Republic of China
| | - Zhiyuan Hu
- Chinese Academy of Sciences Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, People's Republic of China
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10
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UDP-GlcNAc pathway: Potential target for inhibitor discovery against M. tuberculosis. Eur J Pharm Sci 2016; 83:62-70. [DOI: 10.1016/j.ejps.2015.12.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 11/29/2015] [Accepted: 12/08/2015] [Indexed: 11/23/2022]
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11
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Brockhausen I, Nair DG, Chen M, Yang X, Allingham JS, Szarek WA, Anastassiades T. Human acetyl-CoA:glucosamine-6-phosphate N-acetyltransferase 1 has a relaxed donor specificity and transfers acyl groups up to four carbons in length. Biochem Cell Biol 2015; 94:197-204. [PMID: 26935656 DOI: 10.1139/bcb-2015-0115] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Glucosamine-6-phosphate N-acetyltransferase1 (GNA1) catalyses the transfer of an acetyl group from acetyl coenzyme A (AcCoA) to glucosamine-6-phosphate (GlcN6P) to form N-acetylglucosamine-6-phosphate (GlcNAc6P), which is an essential intermediate in UDP-GlcNAc biosynthesis. An analog of GlcNAc, N-butyrylglucosamine (GlcNBu) has shown healing properties for bone and articular cartilage in animal models of arthritis. The goal of this work was to examine whether GNA1 has the ability to transfer a butyryl group from butyryl-CoA to GlcN6P to form GlcNBu6P, which can then be converted to GlcNBu. We developed fluorescent and radioactive assays and examined the donor specificity of human GNA1. Acetyl, propionyl, n-butyryl, and isobutyryl groups were all transferred to GlcN6P, but isovaleryl-CoA and decanoyl-CoA did not serve as donor substrates. Site-specific mutants were produced to examine the role of amino acids potentially affecting the size and properties of the AcCoA binding pocket. All of the wild type and mutant enzymes showed activities of both acetyl and butyryl transfer and can therefore be used for the enzymatic synthesis of GlcNBu for biomedical applications.
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Affiliation(s)
- Inka Brockhausen
- a Department of Medicine, Division of Rheumatology, Queen's University, Kingston, ON K7L 3N6, Canada.,b Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON K7L 3N6, Canada
| | - Dileep G Nair
- a Department of Medicine, Division of Rheumatology, Queen's University, Kingston, ON K7L 3N6, Canada.,c Ministry of Higher Education, Sur College of Applied Sciences, Sur, Sultanate of Oman
| | - Min Chen
- b Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON K7L 3N6, Canada.,d School of Life Sciences and The State Key Laboratory of Microbial Technology, Shandong University, Jinan, Shandong, 250100, China
| | - Xiaojing Yang
- b Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON K7L 3N6, Canada
| | - John S Allingham
- b Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON K7L 3N6, Canada
| | - Walter A Szarek
- e Department of Chemistry, Queen's University, Kingston, ON K7L 3N6, Canada
| | - Tassos Anastassiades
- a Department of Medicine, Division of Rheumatology, Queen's University, Kingston, ON K7L 3N6, Canada.,b Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON K7L 3N6, Canada
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12
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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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13
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Liu Y, Cai DX, Wang L, Li JZ, Wang WN. Glucosamine: fructose-6-phosphate amidotransferase in the white shrimp Litopenaeus vannamei: characterization and regulation under alkaline and cadmium stress. ECOTOXICOLOGY (LONDON, ENGLAND) 2015; 24:1754-1764. [PMID: 25956985 DOI: 10.1007/s10646-015-1480-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 04/30/2015] [Indexed: 06/04/2023]
Abstract
Heavy metal residues and chemical contaminators considered as relevant sources of aquatic environmental pollutants have a generally immunosuppressive effect on aquatic organisms, depressing metabolic activities and immune response. Glutamine: fructose-6-phosphate aminotransferase (GFAT, EC2.6.1.16) is the first, and rate-limiting, enzyme in the hexosamine biosynthetic pathway, and is involved in the regulation of chitin biosynthesis and glycosylation of proteins. We have isolated and characterized GFAT from the white shrimp Litopenaeus vannamei. Amino acid sequence similarity of the Lv-GFAT (L.vannamei-GFAT) was highest to GFATs isolated from insects and mammals (83 % similarity to that of Haemaphysalis longicornis). The open-reading frame of the Lv-GFAT codes for a protein of 41.6 kDa with a calculated isoelectric point of 5.03. RT-PCR assays showed that endogenous Lv-GFAT mRNA is most strongly expressed in the intestine. Further analysis of Lv-GFAT gene expression in hepatopancreas by quantitative real-time PCR demonstrated that Lv-GFAT transcript levels increased when the shrimp were exposed to alkaline pH (9.3) and cadmium stress, but the time when its mRNA expression level peaked differed under these stresses. We also first expressed the recombinant protein of GFAT from shrimps in Escherichia coli. Western blot analyses confirmed that the Lv-GFAT protein was strongly expressed in the hepatopancreas after exposure to the LC-Cd stress. These results suggest that Lv-GFAT expression is stimulated by alkaline pH and cadmium stress and that it may play important roles in resistance of shrimp to environmental stresses.
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Affiliation(s)
- Y Liu
- Key Laboratory of Ecology and Environmental Science in Guangdong Higher Education, Guangdong Provincial Key Laboratory for Healthy and Safe Aquaculture, College of Life Science, South China Normal University, Guangzhou, 510631, People's Republic of China
| | - D X Cai
- Key Laboratory of Ecology and Environmental Science in Guangdong Higher Education, Guangdong Provincial Key Laboratory for Healthy and Safe Aquaculture, College of Life Science, South China Normal University, Guangzhou, 510631, People's Republic of China
| | - L Wang
- Key Laboratory of Ecology and Environmental Science in Guangdong Higher Education, Guangdong Provincial Key Laboratory for Healthy and Safe Aquaculture, College of Life Science, South China Normal University, Guangzhou, 510631, People's Republic of China
| | - J Z Li
- Key Laboratory of Ecology and Environmental Science in Guangdong Higher Education, Guangdong Provincial Key Laboratory for Healthy and Safe Aquaculture, College of Life Science, South China Normal University, Guangzhou, 510631, People's Republic of China
| | - W N Wang
- Key Laboratory of Ecology and Environmental Science in Guangdong Higher Education, Guangdong Provincial Key Laboratory for Healthy and Safe Aquaculture, College of Life Science, South China Normal University, Guangzhou, 510631, People's Republic of China.
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14
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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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15
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Dorfmueller HC, Fang W, Rao FV, Blair DE, Attrill H, van Aalten DMF. Structural and biochemical characterization of a trapped coenzyme A adduct of Caenorhabditis elegans glucosamine-6-phosphate N-acetyltransferase 1. ACTA CRYSTALLOGRAPHICA SECTION D: BIOLOGICAL CRYSTALLOGRAPHY 2012; 68:1019-29. [PMID: 22868768 PMCID: PMC3413214 DOI: 10.1107/s0907444912019592] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/26/2012] [Accepted: 05/02/2012] [Indexed: 01/31/2023]
Abstract
Glucosamine-6-phosphate N-acetyltransferase is an essential enzyme of the eukaryotic UDP-GlcNAc biosynthetic pathway. A crystal structure at 1.55 Å resolution revealed a highly unusual covalent product complex and biochemical studies investigated the function of a fully conserved active-site cysteine. Glucosamine-6-phosphate N-acetyltransferase 1 (GNA1) produces GlcNAc-6-phosphate from GlcN-6-phosphate and acetyl coenzyme A. Early mercury-labelling experiments implicated a conserved cysteine in the reaction mechanism, whereas recent structural data appear to support a mechanism in which this cysteine plays no role. Here, two crystal structures of Caenorhabditis elegans GNA1 are reported, revealing an unusual covalent complex between this cysteine and the coenzyme A product. Mass-spectrometric and reduction studies showed that this inactive covalent complex can be reactivated through reduction, yet mutagenesis of the cysteine supports a previously reported bi-bi mechanism. The data unify the apparently contradictory earlier reports on the role of a cysteine in the GNA1 active site.
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Affiliation(s)
- Helge C Dorfmueller
- Division of Molecular Microbiology, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland
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16
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Characterization, localization, essentiality, and high-resolution crystal structure of glucosamine 6-phosphate N-acetyltransferase from Trypanosoma brucei. EUKARYOTIC CELL 2011; 10:985-97. [PMID: 21531872 DOI: 10.1128/ec.05025-11] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A gene predicted to encode Trypanosoma brucei glucosamine 6-phosphate N-acetyltransferase (TbGNA1; EC 2.3.1.4) was cloned and expressed in Escherichia coli. The recombinant protein was enzymatically active, and its high-resolution crystal structure was obtained at 1.86 Å. Endogenous TbGNA1 protein was localized to the peroxisome-like microbody, the glycosome. A bloodstream-form T. brucei GNA1 conditional null mutant was constructed and shown to be unable to sustain growth in vitro under nonpermissive conditions, demonstrating that there are no metabolic or nutritional routes to UDP-GlcNAc other than via GlcNAc-6-phosphate. Analysis of the protein glycosylation phenotype of the TbGNA1 mutant under nonpermissive conditions revealed that poly-N-acetyllactosamine structures were greatly reduced in the parasite and that the glycosylation profile of the principal parasite surface coat component, the variant surface glycoprotein (VSG), was modified. The significance of results and the potential of TbGNA1 as a novel drug target for African sleeping sickness are discussed.
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17
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Noble SM, French S, Kohn LA, Chen V, Johnson AD. Systematic screens of a Candida albicans homozygous deletion library decouple morphogenetic switching and pathogenicity. Nat Genet 2010; 42:590-8. [PMID: 20543849 PMCID: PMC2893244 DOI: 10.1038/ng.605] [Citation(s) in RCA: 527] [Impact Index Per Article: 37.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2010] [Accepted: 05/12/2010] [Indexed: 01/07/2023]
Abstract
Candida albicans is the most common cause of serious fungal disease in humans. Creation of isogenic null mutants of this diploid organism, which requires sequential gene targeting, allows dissection of virulence mechanisms. Published analyses of such mutants show a near-perfect correlation between C. albicans pathogenicity and the ability to undergo a yeast-to-hypha morphological switch in vitro. However, most studies used mutants constructed with a marker that is itself a virulence determinant and therefore complicates their interpretation. Using alternative markers, we created ~3000 homozygous deletion strains affecting 674 genes or roughly 11% of the C. albicans genome. Screening for infectivity in a mouse model and for morphological switching and cell proliferation in vitro, we identified 115 infectivity-attenuated mutants, of which nearly half demonstrated normal morphological switching and proliferation. Analysis of such mutants identified the glycolipid, glucosylceramide, as the first small molecule synthesized by this pathogen to be required specifically for virulence.
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Affiliation(s)
- Suzanne M Noble
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, California, USA.
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18
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Structural and kinetic differences between human and Aspergillus fumigatus D-glucosamine-6-phosphate N-acetyltransferase. Biochem J 2009; 415:217-23. [PMID: 18601654 DOI: 10.1042/bj20081000] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Aspergillus fumigatus is the causative agent of aspergillosis, a frequently invasive colonization of the lungs of immunocompromised patients. GNA1 (D-glucosamine-6-phosphate N-acetyltransferase) catalyses the acetylation of GlcN-6P (glucosamine-6-phosphate) to GlcNAc-6P (N-acetylglucosamine-6-phosphate), a key intermediate in the UDP-GlcNAc biosynthetic pathway. Gene disruption of gna1 in yeast and Candida albicans has provided genetic validation of the enzyme as a potential target. An understanding of potential active site differences between the human and A. fumigatus enzymes is required to enable further work aimed at identifying selective inhibitors for the fungal enzyme. In the present study, we describe crystal structures of both human and A. fumigatus GNA1, as well as their kinetic characterization. The structures show significant differences in the sugar-binding site with, in particular, several non-conservative substitutions near the phosphate-binding pocket. Mutagenesis targeting these differences revealed drastic effects on steady-state kinetics, suggesting that the differences could be exploitable with small-molecule inhibitors.
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19
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Vicente JB, Ehrenkaufer GM, Saraiva LM, Teixeira M, Singh U. Entamoeba histolytica modulates a complex repertoire of novel genes in response to oxidative and nitrosative stresses: implications for amebic pathogenesis. Cell Microbiol 2008; 11:51-69. [PMID: 18778413 DOI: 10.1111/j.1462-5822.2008.01236.x] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Upon host infection, the protozoan parasite Entamoeba histolytica is confronted with reactive oxygen and nitrogen species and must survive these stresses in order to cause invasive disease. We analysed the parasite's response to oxidative and nitrosative stresses, probing the transcriptional changes of trophozoites of a pathogenic strain after a 60 min exposure to H2O2 (1 mM) or a NO donor (dipropylenetriamine-NONOate, 200 microM), using whole-genome DNA microarrays. Genes encoding reactive oxygen and nitrogen species detoxification enzymes had high transcriptional levels under basal conditions and upon exposure to both stresses. On a whole-genome level, there was significant modulation of gene expression by H2O2 (286 genes regulated) and dipropylenetriamine-NONOate (1036 genes regulated) with a significant overlap of genes modulated under both conditions (164 genes). A number of transcriptionally regulated genes were in signalling/regulatory and repair/metabolic pathways. However, the majority of genes with altered transcription encode unknown proteins, suggesting as yet unraveled response pathways in E. histolytica. Trophozoites of a non-pathogenic E. histolytica strain had a significantly muted transcriptional response to H2O2 compared with the pathogenic strain, hinting that differential response to oxidative stress may be one factor that contributes to the pathogenic potential of E. histolytica.
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Affiliation(s)
- João B Vicente
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305-5107, USA
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20
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Wang J, Zhou YF, Li LF, Liang YH, Su XD. Purification, crystallization and preliminary X-ray analysis of the glucosamine-6-phosphate N-acetyltransferase from human liver. Acta Crystallogr Sect F Struct Biol Cryst Commun 2006; 62:1097-9. [PMID: 17077487 PMCID: PMC2225216 DOI: 10.1107/s1744309106037730] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2006] [Accepted: 09/16/2006] [Indexed: 11/10/2022]
Abstract
Glucosamine-6-phosphate N-acetyltransferase from human liver, which catalyzes the transfer of an acetyl group from acetyl coenzyme A (AcCoA) to the primary amine of D-glucosamine 6-phosphate to form N-acetyl-D-glucosamine 6-phosphate, was expressed in a soluble form from Escherichia coli strain BL21 (DE3). The protein was purified to homogeneity using Ni(2+)-chelating chromatography followed by size-exclusion chromatography. Crystals of the protein were obtained by the hanging-drop vapour-diffusion method and diffracted to 2.6 A resolution. The crystals belonged to space group P4(1)2(1)2 or P4(3)2(1)2, with unit-cell parameters a = b = 50.08, c = 142.88 A.
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Affiliation(s)
- Juan Wang
- National Laboratory of Protein Engineering and Plant Genetic Engineering, Peking University, Beijing 100871, People’s Republic of China
- Department of Biochemistry and Molecular Biology, College of Life Sciences, Peking University, Beijing 100871, People’s Republic of China
| | - Yan-Feng Zhou
- National Laboratory of Protein Engineering and Plant Genetic Engineering, Peking University, Beijing 100871, People’s Republic of China
- Department of Biochemistry and Molecular Biology, College of Life Sciences, Peking University, Beijing 100871, People’s Republic of China
| | - Lan-Fen Li
- National Laboratory of Protein Engineering and Plant Genetic Engineering, Peking University, Beijing 100871, People’s Republic of China
- Department of Biochemistry and Molecular Biology, College of Life Sciences, Peking University, Beijing 100871, People’s Republic of China
| | - Yu-He Liang
- National Laboratory of Protein Engineering and Plant Genetic Engineering, Peking University, Beijing 100871, People’s Republic of China
- Department of Biochemistry and Molecular Biology, College of Life Sciences, Peking University, Beijing 100871, People’s Republic of China
- Correspondence e-mail:
| | - Xiao-Dong Su
- National Laboratory of Protein Engineering and Plant Genetic Engineering, Peking University, Beijing 100871, People’s Republic of China
- Department of Biochemistry and Molecular Biology, College of Life Sciences, Peking University, Beijing 100871, People’s Republic of China
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21
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Abstract
D-Glucosamine is an important building block of major structural components of the fungal cell wall, namely chitin, chitosan and mannoproteins. Other amino sugars, such as D-mannosamine and D-galactosamine, relatively abundant in higher eukaryotes, rarely occur in fungal cells and are actually absent from yeast and yeast-like fungi. The glucosamine-containing sugar nucleotide UDP-GlcNAc is synthesized in yeast cells in a four-step cytoplasmic pathway. This article provides a comprehensive overview of the present knowledge on the enzymes catalysing the particular steps of the pathway in Candida albicans and Saccharomyces cerevisiae, with a special emphasis put on mechanisms of the catalysed reactions, regulation of activity and perspectives for exploitation of enzymes participating in UDP-GlcNAc biosynthesis as potential targets for antifungal chemotherapy.
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Affiliation(s)
- Sławomir Milewski
- Department of Pharmaceutical Technology and Biochemistry, Gdańsk University of Technology, Gdańsk, Poland.
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22
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Andrade RV, Da Silva SP, Torres FAG, Poças-Fonseca MJ, Silva-Pereira I, Maranhão AQ, Campos EG, Moraes LMP, Jesuíno RSA, Pereira M, Soares CMA, Walter MEMT, Carvalho MJA, Almeida NF, Brigido MM, Felipe MSS. Overview and perspectives on the transcriptome of Paracoccidioides brasiliensis. Rev Iberoam Micol 2005; 22:203-12. [PMID: 16499412 DOI: 10.1016/s1130-1406(05)70044-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
Paracoccidioides brasiliensis is a dimorphic and thermo-regulated fungus which is the causative agent of paracoccidioidomycosis, an endemic disease widespread in Latin America that affects 10 million individuals. Pathogenicity is assumed to be a consequence of the dimorphic transition from mycelium to yeast cells during human infection. This review shows the results of the P. brasiliensis transcriptome project which generated 6,022 assembled groups from mycelium and yeast phases. Computer analysis using the tools of bioinformatics revealed several aspects from the transcriptome of this pathogen such as: general and differential metabolism in mycelium and yeast cells; cell cycle, DNA replication, repair and recombination; RNA biogenesis apparatus; translation and protein fate machineries; cell wall; hydrolytic enzymes; proteases; GPI-anchored proteins; molecular chaperones; insights into drug resistance and transporters; oxidative stress response and virulence. The present analysis has provided a more comprehensive view of some specific features considered relevant for the understanding of basic and applied knowledge of P. brasiliensis.
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Affiliation(s)
- Rosângela V Andrade
- Laboratorio de Biologia Molecular, Departamento de Biologia Celular, Universidade de Brasília, Brasilia, DF, 70910-900, Brazil
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23
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Brand A, MacCallum DM, Brown AJP, Gow NAR, Odds FC. Ectopic expression of URA3 can influence the virulence phenotypes and proteome of Candida albicans but can be overcome by targeted reintegration of URA3 at the RPS10 locus. EUKARYOTIC CELL 2005; 3:900-9. [PMID: 15302823 PMCID: PMC500875 DOI: 10.1128/ec.3.4.900-909.2004] [Citation(s) in RCA: 229] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Uridine auxotrophy, based on disruption of both URA3 alleles in diploid Candida albicans strain SC5314, has been widely used to select gene deletion mutants created in this fungus by "Ura-blasting" and PCR-mediated disruption. We compared wild-type URA3 expression with levels in mutant strains where URA3 was positioned either within deleted genes or at the highly expressed RPS10 locus. URA3 expression levels differed significantly and correlated with the specific activity of Ura3p, orotidine 5'-monophosphate decarboxylase. Reduced URA3 expression following integration at the GCN4 locus was associated with an attenuation of virulence. Furthermore, a comparison of the SC5314 (URA3) and CAI-4 (ura3) proteomes revealed that inactivation of URA3 caused significant changes in the levels of 14 other proteins. The protein levels of all except one were partially or fully restored by the reintegration of a single copy of URA3 at the RPS10 locus. Transcript levels of genes expressed ectopically at this locus in reconstituted heterozygous mutants also matched the levels found when the genes were expressed at their native loci. Therefore, phenotypic changes in C. albicans can be associated with the selectable marker rather than the target gene. Reintegration of URA3 at an appropriate expression locus such as RPS10 can offset most problems related to the phenotypic changes associated with gene knockout methodologies.
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Affiliation(s)
- Alexandra Brand
- School of Medical Sciences, Institute of Medical Sciences, Aberdeen AB25 2ZD, Scotland, United Kingdom
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24
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Keon J, Antoniw J, Rudd J, Skinner W, Hargreaves J, Hammond-Kosack K. Analysis of expressed sequence tags from the wheat leaf blotch pathogen Mycosphaerella graminicola (anamorph Septoria tritici). Fungal Genet Biol 2005; 42:376-89. [PMID: 15809003 DOI: 10.1016/j.fgb.2004.12.005] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2004] [Revised: 12/20/2004] [Accepted: 12/29/2004] [Indexed: 10/25/2022]
Abstract
Mycosphaerella graminicola is a major fungal pathogen of wheat as the causal agent of Septoria leaf blotch disease. As a first step toward a greater understanding of the mechanism of host infection we have generated, sequenced, and analyzed three M. graminicola EST libraries from conditions predicted to resemble independent phases of the host infection process, including one library generated from the fungus during interaction with its host. A total of 5180 ESTs were sequenced and clustered into 886 contigs and 2039 singletons to give a set of 2925 unique sequences (unisequences). BLASTX analysis revealed 33% of the unknown M. graminicola unisequences to be orphans. Very limited inter-library overlap of expression was seen with the majority of unisequences (contigs and singletons) being library-specific. Analysis of EST redundancy between libraries demonstrated a significant difference in gene expression in the three conditions. Comparisons made against fully sequenced genomes revealed most M. graminicola sequences to be homologous to genes present in both pathogenic and non-pathogenic Ascomycete filamentous fungi. A range of sequences having significant homology to verified pathogenicity/virulence genes (HvPV-genes) of either plant or mammalian fungal and Oomycete pathogens were also identified (<1e-20). The generation of, and the diversity present within, this EST collection will facilitate future efforts aimed at a more detailed study of the transcriptome of the fungus during host infection.
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Affiliation(s)
- John Keon
- Wheat Pathogenesis Programme, Plant-Pathogen Interactions Division, Rothamsted Research, Harpenden, Herts AL5 2JQ, UK
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25
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Kato N, Mueller CR, Wessely V, Lan Q, Christensen BM. Mosquito glucosamine-6-phosphate N-acetyltransferase: cDNA, gene structure and enzyme kinetics. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2005; 35:637-646. [PMID: 15857769 DOI: 10.1016/j.ibmb.2005.02.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2004] [Revised: 02/10/2005] [Accepted: 02/24/2005] [Indexed: 05/24/2023]
Abstract
Mosquito midgut epithelial cells secrete digestive enzymes as well as components of the peritrophic matrix in response to blood-feeding. The peritrophic matrix is composed of proteins, glycoproteins and chitin fibrils in a proteoglycan matrix and may function to protect the midgut epithelium from mechanical damage and insult from pathogens and toxins. Chitin biosynthesis takes place via the hexosamine pathway converting fructose-6-phosphate to UDP-N-acetylglucosamine, which is then polymerized to chitin by chitin synthase. Glucosamine-6-phosphate N-acetyltransferase (GNA) is one of the hexosamine pathway enzymes and catalyzes the transfer of the acetyl group from acetyl-CoA to the primary amine of glucosamine-6-phosphate. We cloned and sequenced the GNA cDNA, gene (AeGna) and its putative promoter regions from Aedes aegypti. AeGna consists of five exons and four introns and lacks a TATA box near the transcription start site. The AeGna cDNA is 1.3 kb in length and the predicted protein is approximately 23.6 kDa. The amino acid sequence of AeGna has high homology to its orthologues. AeGna mRNA is constitutively expressed in all developmental stages and blood-feeding causes no obvious effect on levels of AeGna transcript in the midgut. The Km value of recombinant GNA for glucosamine-6-phosphate was 330 microM and the Km for acetyl-CoA was 500 microM.
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Affiliation(s)
- Nobutaka Kato
- Department of Animal Health and Biomedical Sciences, 1656 Linden Dr. University of Wisconsin-Madison, Madison, WI 53706, USA
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26
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Kato N, Dasgupta R, Smartt CT, Christensen BM. Glucosamine:fructose-6-phosphate aminotransferase: gene characterization, chitin biosynthesis and peritrophic matrix formation in Aedes aegypti. INSECT MOLECULAR BIOLOGY 2002; 11:207-216. [PMID: 12000639 DOI: 10.1046/j.1365-2583.2002.00326.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Glucosamine:fructose-6-phosphate aminotransferase (GFAT) catalyses the formation of glucosamine 6-phosphate and is the first and rate-limiting enzyme of the hexosamine biosynthetic pathway. The final product of the hexosamine pathway, UDP-N-acetyl glucosamine, is an active precursor of numerous macromolecules containing amino sugars, including chitin in fungi and arthropods. Chitin is one of the essential components of insect cuticle and peritrophic matrix. The peritrophic matrix is produced in the midgut of mosquitoes in response to bloodfeeding, and may affect vector competence by serving as a physical barrier to pathogens. It is hypothesized that GFAT plays a regulatory role in biosynthesis of chitin and peritrophic matrix formation in insects. We cloned and sequenced the GFAT gene (AeGfat-1) and its 5' regulatory region from Aedes aegypti. There is no intron in AeGfat-1 and there are two potential transcription start sites. AeGfat-1 cDNA is 3.4 kb in length and its putative translation product is 75.4 kDa. The amino acid sequence of GFAT is highly conserved in lower and higher eukaryotes, as well as in bacteria. AeGfat-1 message is constitutively expressed but is gradually up-regulated in the midgut after bloodfeeding. The putative regulatory region of the gene contains the ecdysone response element, E74, and Broad complex motifs, similar to what is found in the glutamine synthetase gene in Ae. aegypti. Results suggest that Ae. aegypti GFAT-1 may have a regulatory role in chitin biosynthesis and peritrophic matrix formation, and probably is under the regulation of ecdysteroids.
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Affiliation(s)
- N Kato
- Department of Animal Health and Biomedical Sciences, University of Wisconsin-Madison, Madison, WI 53706, USA
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27
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Singh P, Ghosh S, Datta A. Attenuation of virulence and changes in morphology in Candida albicans by disruption of the N-acetylglucosamine catabolic pathway. Infect Immun 2001; 69:7898-903. [PMID: 11705974 PMCID: PMC98888 DOI: 10.1128/iai.69.12.7898-7903.2001] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
A Candida albicans mutant with mutations in the N-acetylglucosamine (GlcNAc) catabolic pathway gene cluster, including the GlcNAc-6-phosphate deacetylase (DAC1), glucosamine-6-phosphate deaminase (NAG1), and GlcNAc kinase (HXK1) genes, was not able to grow on amino sugars, exhibited highly attenuated virulence in a murine systemic candidiasis model, and was less adherent to human buccal epithelial cells in vitro. No germ tubes were formed by the mutant after induction with GlcNAc, but the mutant exhibited hyperfilamentation under stress-induced filamentation conditions. In addition, the GlcNAc catabolic pathway played a vital role in determining the colony phenotype. Our results imply that this pathway is very important because of its diverse links with pathways involved in virulence and morphogenesis of the organism.
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Affiliation(s)
- P Singh
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India
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28
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Peneff C, Mengin-Lecreulx D, Bourne Y. The crystal structures of Apo and complexed Saccharomyces cerevisiae GNA1 shed light on the catalytic mechanism of an amino-sugar N-acetyltransferase. J Biol Chem 2001; 276:16328-34. [PMID: 11278591 DOI: 10.1074/jbc.m009988200] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The yeast enzymes involved in UDP-GlcNAc biosynthesis are potential targets for antifungal agents. GNA1, a novel member of the Gcn5-related N-acetyltransferase (GNAT) superfamily, participates in UDP-GlcNAc biosynthesis by catalyzing the formation of GlcNAc6P from AcCoA and GlcN6P. We have solved three crystal structures corresponding to the apo Saccharomyces cerevisiae GNA1, the GNA1-AcCoA, and the GNA1-CoA-GlcNAc6P complexes and have refined them to 2.4, 1.3, and 1.8 A resolution, respectively. These structures not only reveal a stable, beta-intertwined, dimeric assembly with the GlcNAc6P binding site located at the dimer interface but also shed light on the catalytic machinery of GNA1 at an atomic level. Hence, they broaden our understanding of structural features required for GNAT activity, provide structural details for related aminoglycoside N-acetyltransferases, and highlight the adaptability of the GNAT superfamily members to acquire various specificities.
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Affiliation(s)
- C Peneff
- UMR 6098 CNRS, 31 chemin Joseph Aiguier, 13402 Marseille Cedex 20, France and UMR 8619 CNRS, Université Paris-Sud, Bâtiment 430, 91405 Orsay Cedex, France
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Navarro-García F, Sánchez M, Nombela C, Pla J. Virulence genes in the pathogenic yeast Candida albicans. FEMS Microbiol Rev 2001; 25:245-68. [PMID: 11250036 DOI: 10.1111/j.1574-6976.2001.tb00577.x] [Citation(s) in RCA: 110] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
In recent years, the incidence of fungal infections has been rising all over the world. Although the amount of research in the field of pathogenic fungi has also increased, there is still a need for the identification of reliable determinants of virulence. In this review, we focus on identified Candida albicans genes whose deletant strains have been tested in experimental virulence assays. We discuss the putative relationship of these genes to virulence and also outline the use of new different systems to examine the precise effect in virulence of different genes.
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Affiliation(s)
- F Navarro-García
- Departamento de Microbiología II, Facultad de Farmacia, Universidad Complutense de Madrid, Spain
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Yamada-Okabe T, Sakamori Y, Mio T, Yamada-Okabe H. Identification and characterization of the genes for N-acetylglucosamine kinase and N-acetylglucosamine-phosphate deacetylase in the pathogenic fungus Candida albicans. EUROPEAN JOURNAL OF BIOCHEMISTRY 2001; 268:2498-505. [PMID: 11298769 DOI: 10.1046/j.1432-1327.2001.02135.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Like bacteria and many fungi, the pathogenic fungus Candida albicans can utilize GlcNAc as a carbon source for growth. A cluster of six genes was identified in the C. albicans genome. One of the genes in the cluster was CaNAG1, which is responsible for GlcN6P deaminase and is therefore essential for GlcNAc-dependent growth. The other five genes were designated CaNAG2, CaNAG3, CaNAG4, CaNAG5 and CaNAG6. The mRNA levels of CaNAG1, CaNAG2 and CaNAG5 were significantly induced by GlcNAc, whereas those of CaNAG3, CaNAG4 and CaNAG6 were not. Neither CaNAG2 nor CaNAG5 was essential for growth, but disruption of CaNAG2 or CaNAG5 greatly retarded the growth of cells using GlcNAc as the sole carbon source. Although no homolog of CaNAG2 or CaNAG5 was found in the Saccharomyces cerevisiae genome, CaNag2p displayed sequence similarities to Escherichia coli nagA, and CaNag5p is homologous to a wide variety of hexose kinases. When expressed as a fusion protein with glutathione S-transferase (GST), CaNag5p produced GlcNAc-P from GlcNAc in the presence of ATP, whereas GST alone did not. Furthermore, the recombinant GST-CaNag2p fusion protein converted GlcNAcP, which was produced by CaNag5p, into GlcNP. These results clearly demonstrate that CaNAG2 and CaNAG5 encode GlcNAcP deacetylase and GlcNAc kinase, respectively. CaNag5p recognized glucose and mannose as substrates, whereas the recently identified human GlcNAc kinase was specific to GlcNAc. Deletion of CaNAG2 or CaNAG5 markedly, and that of CaNAG1 moderately, attenuated the virulence of C. albicans in a mouse systemic infection model. Thus, it appears that GlcNAc metabolism of C. albicans is closely associated with its virulence.
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Affiliation(s)
- T Yamada-Okabe
- Department of Hygiene, School of Medicine, Yokohama City University, Japan
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