1
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Zhang Y, Hamada K, Satake M, Sengoku T, Goto Y, Suga H. Switching Prenyl Donor Specificities of Cyanobactin Prenyltransferases. J Am Chem Soc 2023; 145:23893-23898. [PMID: 37877712 DOI: 10.1021/jacs.3c07373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2023]
Abstract
Prenyltransferases in cyanobactin biosynthesis are of growing interest as peptide alkylation biocatalysts, but their prenylation modes characterized so far have been limited to dimethylallylation (C5) or geranylation (C10). Here we engaged in structure-guided engineering of the prenyl-binding pocket of a His-C2-geranyltransferase LimF to modulate its prenylation mode. Contraction of the pocket by a single mutation led to a His-C2-dimethylallyltransferase. More importantly, pocket expansion by a double mutation successfully repurposed LimF for farnesylation (C15), which is an unprecedented mode in this family. Furthermore, the obtained knowledge of the essential residues to construct the farnesyl-binding pocket has allowed for rational design of a Tyr-O-farnesyltransferase by a triple mutation of a Tyr-O-dimethylallyltransferase PagF. These results provide an approach to manipulate the prenyl specificity of cyanobactin prenyltransferases, broadening the chemical space covered by this class of enzymes and expanding the toolbox of peptide alkylation biocatalysts.
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Affiliation(s)
- Yuchen Zhang
- Department of Chemistry, Graduate School of Science, The University of Tokyo, Bunkyo, Tokyo 113-0033, Japan
| | - Keisuke Hamada
- Department of Biochemistry, Graduate School of Medicine, Yokohama City University, Yokohama 236-0004, Japan
| | - Masayuki Satake
- Department of Chemistry, Graduate School of Science, The University of Tokyo, Bunkyo, Tokyo 113-0033, Japan
| | - Toru Sengoku
- Department of Biochemistry, Graduate School of Medicine, Yokohama City University, Yokohama 236-0004, Japan
| | - Yuki Goto
- Department of Chemistry, Graduate School of Science, The University of Tokyo, Bunkyo, Tokyo 113-0033, Japan
| | - Hiroaki Suga
- Department of Chemistry, Graduate School of Science, The University of Tokyo, Bunkyo, Tokyo 113-0033, Japan
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2
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Jung D, Bachmann HS. Regulation of protein prenylation. Biomed Pharmacother 2023; 164:114915. [PMID: 37236024 DOI: 10.1016/j.biopha.2023.114915] [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: 03/27/2023] [Revised: 05/17/2023] [Accepted: 05/18/2023] [Indexed: 05/28/2023] Open
Abstract
Prenyltransferases (PTases) are known to play a role in embryonic development, normal tissue homeostasis and cancer by posttranslationally modifying proteins involved in these processes. They are being discussed as potential drug targets in an increasing number of diseases, ranging from Alzheimer's disease to malaria. Protein prenylation and the development of specific PTase inhibitors (PTIs) have been subject to intense research in recent decades. Recently, the FDA approved lonafarnib, a specific farnesyltransferase inhibitor that acts directly on protein prenylation; and bempedoic acid, an ATP citrate lyase inhibitor that might alter intracellular isoprenoid composition, the relative concentrations of which can exert a decisive influence on protein prenylation. Both drugs represent the first approved agent in their respective substance class. Furthermore, an overwhelming number of processes and proteins that regulate protein prenylation have been identified over the years, many of which have been proposed as molecular targets for pharmacotherapy in their own right. However, certain aspects of protein prenylation, such as the regulation of PTase gene expression or the modulation of PTase activity by phosphorylation, have attracted less attention, despite their reported influence on tumor cell proliferation. Here, we want to summarize the advances regarding our understanding of the regulation of protein prenylation and the potential implications for drug development. Additionally, we want to suggest new lines of investigation that encompass the search for regulatory elements for PTases, especially at the genetic and epigenetic levels.
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Affiliation(s)
- Dominik Jung
- Institute of Pharmacology and Toxicology, Center for Biomedical Education and Research (ZBAF), School of Medicine, Faculty of Health, Witten/Herdecke University, Witten, Germany
| | - Hagen S Bachmann
- Institute of Pharmacology and Toxicology, Center for Biomedical Education and Research (ZBAF), School of Medicine, Faculty of Health, Witten/Herdecke University, Witten, Germany.
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3
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Wang Y, Xu F, Nichols CB, Shi Y, Hellinga HW, Alspaugh JA, Distefano MD, Beese LS. Structure-Guided Discovery of Potent Antifungals that Prevent Ras Signaling by Inhibiting Protein Farnesyltransferase. J Med Chem 2022; 65:13753-13770. [PMID: 36218371 PMCID: PMC10755971 DOI: 10.1021/acs.jmedchem.2c00902] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Infections by fungal pathogens are difficult to treat due to a paucity of antifungals and emerging resistances. Next-generation antifungals therefore are needed urgently. We have developed compounds that prevent farnesylation of Cryptoccoccus neoformans Ras protein by inhibiting protein farnesyltransferase with 3-4 nanomolar affinities. Farnesylation directs Ras to the cell membrane and is required for infectivity of this lethal pathogenic fungus. Our high-affinity compounds inhibit fungal growth with 3-6 micromolar minimum inhibitory concentrations (MICs), 4- to 8-fold better than Fluconazole, an antifungal commonly used in the clinic. Compounds bound with distinct inhibition mechanisms at two alternative, partially overlapping binding sites, accessed via different inhibitor conformations. We showed that antifungal potency depends critically on the selected inhibition mechanism because this determines the efficacy of an inhibitor at low in vivo levels of enzyme and farnesyl substrate. We elucidated how chemical modifications of the antifungals encode desired inhibitor conformation and concomitant inhibitory mechanism.
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Affiliation(s)
- You Wang
- Department of Biochemistry, Duke University School
of Medicine, Durham, North Carolina, USA 27710
| | - Feng Xu
- Department of Chemistry, University of Minnesota,
Minneapolis, Minnesota, USA 55455
| | - Connie B. Nichols
- Department of Medicine, Duke University School of
Medicine, Durham, North Carolina, USA 27710
- Department of Molecular Genetics and Microbiology,
Duke University School of Medicine, Durham, North Carolina, USA 27710
| | - Yuqian Shi
- Department of Biochemistry, Duke University School
of Medicine, Durham, North Carolina, USA 27710
| | - Homme W. Hellinga
- Department of Biochemistry, Duke University School
of Medicine, Durham, North Carolina, USA 27710
| | - J. Andrew Alspaugh
- Department of Medicine, Duke University School of
Medicine, Durham, North Carolina, USA 27710
- Department of Molecular Genetics and Microbiology,
Duke University School of Medicine, Durham, North Carolina, USA 27710
| | - Mark D. Distefano
- Department of Chemistry, University of Minnesota,
Minneapolis, Minnesota, USA 55455
| | - Lorena S. Beese
- Department of Biochemistry, Duke University School
of Medicine, Durham, North Carolina, USA 27710
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4
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Chang HY, Cheng TH, Wang AHJ. Structure, catalysis, and inhibition mechanism of prenyltransferase. IUBMB Life 2020; 73:40-63. [PMID: 33246356 PMCID: PMC7839719 DOI: 10.1002/iub.2418] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2020] [Revised: 11/02/2020] [Accepted: 11/14/2020] [Indexed: 12/31/2022]
Abstract
Isoprenoids, also known as terpenes or terpenoids, represent a large family of natural products composed of five‐carbon isopentenyl diphosphate or its isomer dimethylallyl diphosphate as the building blocks. Isoprenoids are structurally and functionally diverse and include dolichols, steroid hormones, carotenoids, retinoids, aromatic metabolites, the isoprenoid side‐chain of ubiquinone, and isoprenoid attached signaling proteins. Productions of isoprenoids are catalyzed by a group of enzymes known as prenyltransferases, such as farnesyltransferases, geranylgeranyltransferases, terpenoid cyclase, squalene synthase, aromatic prenyltransferase, and cis‐ and trans‐prenyltransferases. Because these enzymes are key in cellular processes and metabolic pathways, they are expected to be potential targets in new drug discovery. In this review, six distinct subsets of characterized prenyltransferases are structurally and mechanistically classified, including (1) head‐to‐tail prenyl synthase, (2) head‐to‐head prenyl synthase, (3) head‐to‐middle prenyl synthase, (4) terpenoid cyclase, (5) aromatic prenyltransferase, and (6) protein prenylation. Inhibitors of those enzymes for potential therapies against several diseases are discussed. Lastly, recent results on the structures of integral membrane enzyme, undecaprenyl pyrophosphate phosphatase, are also discussed.
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Affiliation(s)
- Hsin-Yang Chang
- Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei, Taiwan
| | - Tien-Hsing Cheng
- Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei, Taiwan
| | - Andrew H-J Wang
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
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5
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LeBlanc EV, Polvi EJ, Veri AO, Privé GG, Cowen LE. Structure-guided approaches to targeting stress responses in human fungal pathogens. J Biol Chem 2020; 295:14458-14472. [PMID: 32796038 DOI: 10.1074/jbc.rev120.013731] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 08/11/2020] [Indexed: 11/06/2022] Open
Abstract
Fungi inhabit extraordinarily diverse ecological niches, including the human body. Invasive fungal infections have a devastating impact on human health worldwide, killing ∼1.5 million individuals annually. The majority of these deaths are attributable to species of Candida, Cryptococcus, and Aspergillus Treating fungal infections is challenging, in part due to the emergence of resistance to our limited arsenal of antifungal agents, necessitating the development of novel therapeutic options. Whereas conventional antifungal strategies target proteins or cellular components essential for fungal growth, an attractive alternative strategy involves targeting proteins that regulate fungal virulence or antifungal drug resistance, such as regulators of fungal stress responses. Stress response networks enable fungi to adapt, grow, and cause disease in humans and include regulators that are highly conserved across eukaryotes as well as those that are fungal-specific. This review highlights recent developments in elucidating crystal structures of fungal stress response regulators and emphasizes how this knowledge can guide the design of fungal-selective inhibitors. We focus on the progress that has been made with highly conserved regulators, including the molecular chaperone Hsp90, the protein phosphatase calcineurin, and the small GTPase Ras1, as well as with divergent stress response regulators, including the cell wall kinase Yck2 and trehalose synthases. Exploring structures of these important fungal stress regulators will accelerate the design of selective antifungals that can be deployed to combat life-threatening fungal diseases.
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Affiliation(s)
- Emmanuelle V LeBlanc
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Elizabeth J Polvi
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Amanda O Veri
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Gilbert G Privé
- Departments of Medical Biophysics and Biochemistry, University of Toronto, Toronto, Ontario, Canada.,Princess Margaret Cancer Centre, Toronto, Ontario, Canada
| | - Leah E Cowen
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
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6
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Souza ACO, Al Abdallah Q, DeJarnette K, Martin-Vicente A, Nywening AV, DeJarnette C, Sansevere EA, Ge W, Palmer GE, Fortwendel JR. Differential requirements of protein geranylgeranylation for the virulence of human pathogenic fungi. Virulence 2020; 10:511-526. [PMID: 31131706 PMCID: PMC6550545 DOI: 10.1080/21505594.2019.1620063] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Protein prenylation is a crucial post-translational modification largely mediated by two heterodimeric enzyme complexes, farnesyltransferase and geranylgeranyltransferase type-I (GGTase-I), each composed of a shared α-subunit and a unique β-subunit. GGTase-I enzymes are validated drug targets that contribute to virulence in Cryptococcus neoformans and to the yeast-to-hyphal transition in Candida albicans. Therefore, we sought to investigate the importance of the α-subunit, RamB, and the β-subunit, Cdc43, of the A. fumigatus GGTase-I complex to hyphal growth and virulence. Deletion of cdc43 resulted in impaired hyphal morphogenesis and thermo-sensitivity, which was exacerbated during growth in rich media. The Δcdc43 mutant also displayed hypersensitivity to cell wall stress agents and to cell wall synthesis inhibitors, suggesting alterations of cell wall biosynthesis or stress signaling. In support of this, analyses of cell wall content revealed decreased amounts of β-glucan in the Δcdc43 strain. Despite strong in vitro phenotypes, the Δcdc43 mutant was fully virulent in two models of murine invasive aspergillosis, similar to the control strain. We further found that a strain expressing the α-subunit gene, ramB, from a tetracycline-inducible promoter was inviable under non-inducing in vitro growth conditions and was virtually avirulent in both mouse models. Lastly, virulence studies using C. albicans strains with tetracycline-repressible RAM2 or CDC43 expression revealed reduced pathogenicity associated with downregulation of either gene in a murine model of disseminated infection. Together, these findings indicate a differential requirement for protein geranylgeranylation for fungal virulence, and further inform the selection of specific prenyltransferases as promising antifungal drug targets for each pathogen.
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Affiliation(s)
- Ana Camila Oliveira Souza
- a Department of Clinical Pharmacy and Translational Science , College of Pharmacy, University of Tennessee Health Science Center , Memphis , TN , USA
| | - Qusai Al Abdallah
- a Department of Clinical Pharmacy and Translational Science , College of Pharmacy, University of Tennessee Health Science Center , Memphis , TN , USA
| | - Kaci DeJarnette
- a Department of Clinical Pharmacy and Translational Science , College of Pharmacy, University of Tennessee Health Science Center , Memphis , TN , USA
| | - Adela Martin-Vicente
- a Department of Clinical Pharmacy and Translational Science , College of Pharmacy, University of Tennessee Health Science Center , Memphis , TN , USA
| | - Ashley V Nywening
- b Department of Molecular Immunology and Biochemistry , College of Graduate Health Sciences, University of Tennessee Health Science Center , Memphis , TN , USA
| | - Christian DeJarnette
- b Department of Molecular Immunology and Biochemistry , College of Graduate Health Sciences, University of Tennessee Health Science Center , Memphis , TN , USA
| | - Emily A Sansevere
- a Department of Clinical Pharmacy and Translational Science , College of Pharmacy, University of Tennessee Health Science Center , Memphis , TN , USA
| | - Wenbo Ge
- a Department of Clinical Pharmacy and Translational Science , College of Pharmacy, University of Tennessee Health Science Center , Memphis , TN , USA
| | - Glen E Palmer
- a Department of Clinical Pharmacy and Translational Science , College of Pharmacy, University of Tennessee Health Science Center , Memphis , TN , USA
| | - Jarrod R Fortwendel
- a Department of Clinical Pharmacy and Translational Science , College of Pharmacy, University of Tennessee Health Science Center , Memphis , TN , USA
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7
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Pianalto KM, Billmyre RB, Telzrow CL, Alspaugh JA. Roles for Stress Response and Cell Wall Biosynthesis Pathways in Caspofungin Tolerance in Cryptococcus neoformans. Genetics 2019; 213:213-227. [PMID: 31266771 PMCID: PMC6727808 DOI: 10.1534/genetics.119.302290] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Accepted: 06/24/2019] [Indexed: 12/14/2022] Open
Abstract
Limited antifungal diversity and availability are growing problems for the treatment of fungal infections in the face of increasing drug resistance. The echinocandins, one of the newest classes of antifungal drugs, inhibit production of a crucial cell wall component. However, these compounds do not effectively inhibit the growth of the opportunistic fungal pathogen Cryptococcus neoformans, despite potent inhibition of the target enzyme in vitro Therefore, we performed a forward genetic screen to identify cellular processes that mediate the relative tolerance of this organism to the echinocandin drug caspofungin. Through these studies, we identified 14 genetic mutants that enhance caspofungin antifungal activity. Rather than directly affecting caspofungin antifungal activity, these mutations seem to prevent the activation of various stress-induced compensatory cellular processes. For example, the pfa4Δ mutant has defects in the palmitoylation and localization of many of its target proteins, including the Ras1 GTPase and the Chs3 chitin synthase, which are both required for caspofungin tolerance. Similarly, we have confirmed the link between caspofungin treatment and calcineurin signaling in this organism, but we suggest a deeper mechanism in which caspofungin tolerance is mediated by multiple pathways downstream of calcineurin function. In summary, we describe here several pathways in C. neoformans that contribute to the complex caspofungin tolerance phenotype in this organism.
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Affiliation(s)
- Kaila M Pianalto
- Department of Medicine, Duke University School of Medicine, Durham, North Carolina 27710
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, North Carolina 27710
| | - R Blake Billmyre
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, North Carolina 27710
| | - Calla L Telzrow
- Department of Medicine, Duke University School of Medicine, Durham, North Carolina 27710
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, North Carolina 27710
| | - J Andrew Alspaugh
- Department of Medicine, Duke University School of Medicine, Durham, North Carolina 27710
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, North Carolina 27710
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8
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Qiao J, Song Y, Ling Z, Liu X, Fang H. ram1 gene, encoding a subunit of farnesyltransferase, contributes to growth, antifungal susceptibility to amphotericin B of Aspergillus fumigatus. Med Mycol 2018; 55:883-889. [PMID: 28159997 DOI: 10.1093/mmy/myx002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2016] [Accepted: 01/05/2017] [Indexed: 11/15/2022] Open
Abstract
Farnesylation, which is catalyzed by farnesyltransferase, is an important posttranslational process. The function of farnesyltransferase has been previously explored in Cryptococcus neoformans and Candida albicans. Aspergillus fumigatus is an important human opportunistic fungal pathogen in immunocompromised patients. Here we discover the role of the ram1 gene, encoding the β-subunit of farnesyltransferase in A. fumigatus, in the fungal growth and antifungal susceptibility. In this study the ram1 gene was disrupted using A. tumefaciens-mediated transformation. The morphology and radial growth of Δram1 were observed. Assays of disk diffusion and broth microdilution were used to determine the susceptibility of Δram1 mutant to commonly clinical used antifungals and the farnesyltransferase inhibitor manumycin A. Deletion of ram1 resulted in a reduced radial growth of A. fumigatus but did not affect the microscopic morphology. Δram1 showed increased susceptibility to the antifungal amphotericin B; however, its susceptibility to azoles and caspofungin was the same to that to the parental strain. Our data indicate that farnesyltransferase is a potential target for design new antifungal agents.
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Affiliation(s)
- Jianjun Qiao
- Department of Dermatology, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Yan Song
- Kidney Disease Center, the First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Zongxin Ling
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Xia Liu
- Department of Intensive Care Unit, the First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Hong Fang
- Department of Dermatology, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
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9
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Jiang H, Zhang X, Chen X, Aramsangtienchai P, Tong Z, Lin H. Protein Lipidation: Occurrence, Mechanisms, Biological Functions, and Enabling Technologies. Chem Rev 2018; 118:919-988. [PMID: 29292991 DOI: 10.1021/acs.chemrev.6b00750] [Citation(s) in RCA: 286] [Impact Index Per Article: 47.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Protein lipidation, including cysteine prenylation, N-terminal glycine myristoylation, cysteine palmitoylation, and serine and lysine fatty acylation, occurs in many proteins in eukaryotic cells and regulates numerous biological pathways, such as membrane trafficking, protein secretion, signal transduction, and apoptosis. We provide a comprehensive review of protein lipidation, including descriptions of proteins known to be modified and the functions of the modifications, the enzymes that control them, and the tools and technologies developed to study them. We also highlight key questions about protein lipidation that remain to be answered, the challenges associated with answering such questions, and possible solutions to overcome these challenges.
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Affiliation(s)
- Hong Jiang
- Howard Hughes Medical Institute, Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States
| | - Xiaoyu Zhang
- Howard Hughes Medical Institute, Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States
| | - Xiao Chen
- Howard Hughes Medical Institute, Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States
| | - Pornpun Aramsangtienchai
- Howard Hughes Medical Institute, Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States
| | - Zhen Tong
- Howard Hughes Medical Institute, Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States
| | - Hening Lin
- Howard Hughes Medical Institute, Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States
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10
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Saleh AA, Jones GW, Tinley FC, Delaney SF, Alabbadi SH, Fenlon K, Doyle S, Owens RA. Systems impact of zinc chelation by the epipolythiodioxopiperazine dithiol gliotoxin in Aspergillus fumigatus: a new direction in natural product functionality. Metallomics 2018; 10:854-866. [DOI: 10.1039/c8mt00052b] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Dithiol gliotoxin (DTG) is a zinc chelator and an inability to dissipate DTG in Aspergillus fumigatus is associated with multiple impacts which are linked to zinc chelation.
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Affiliation(s)
| | - Gary W. Jones
- Department of Biology
- Maynooth University
- Co. Kildare
- Ireland
- Centre for Biomedical Research
| | | | | | | | - Keith Fenlon
- Department of Biology
- Maynooth University
- Co. Kildare
- Ireland
| | - Sean Doyle
- Department of Biology
- Maynooth University
- Co. Kildare
- Ireland
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11
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Affiliation(s)
- J Andrew Alspaugh
- a Department of Medicine, and Department of Molecular Genetics & Microbiology , Duke University School of Medicine , Durham , NC , USA
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12
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13
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Norton TS, Al Abdallah Q, Hill AM, Lovingood RV, Fortwendel JR. The Aspergillus fumigatus farnesyltransferase β-subunit, RamA, mediates growth, virulence, and antifungal susceptibility. Virulence 2017; 8:1401-1416. [PMID: 28489963 PMCID: PMC5711395 DOI: 10.1080/21505594.2017.1328343] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Post-translational prenylation mechanisms, including farnesylation and geranylgeranylation, mediate both subcellular localization and protein-protein interaction in eukaryotes. The prenyltransferase complex is an αβ heterodimer in which the essential α-subunit is common to both the farnesyltransferase and the geranylgeranyltransferase type-I enzymes. The β-subunit is unique to each enzyme. Farnesyltransferase activity is an important mediator of protein localization and subsequent signaling for multiple proteins, including Ras GTPases. Here, we examined the importance of protein farnesylation in the opportunistic fungal pathogen Aspergillus fumigatus through generation of a mutant lacking the farnesyltransferase β-subunit, ramA. Although farnesyltransferase activity was found to be non-essential in A. fumigatus, diminished hyphal outgrowth, delayed polarization kinetics, decreased conidial viability, and irregular distribution of nuclei during polarized growth were noted upon ramA deletion (ΔramA). Although predicted to be a target of the farnesyltransferase enzyme complex, we found that localization of the major A. fumigatus Ras GTPase protein, RasA, was only partially regulated by farnesyltransferase activity. Furthermore, the farnesyltransferase-deficient mutant exhibited attenuated virulence in a murine model of invasive aspergillosis, characterized by decreased tissue invasion and development of large, swollen hyphae in vivo. However, loss of ramA also led to a Cyp51A/B-independent increase in resistance to triazole antifungal drugs. Our findings indicate that protein farnesylation underpins multiple cellular processes in A. fumigatus, likely due to the large body of proteins affected by ramA deletion.
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Affiliation(s)
- Tiffany S Norton
- a Department of Microbiology and Immunology , University of South Alabama , Mobile , AL , USA
| | - Qusai Al Abdallah
- b Department of Clinical Pharmacy , University of Tennessee Health Science Center , Memphis , TN , USA
| | - Amy M Hill
- a Department of Microbiology and Immunology , University of South Alabama , Mobile , AL , USA
| | - Rachel V Lovingood
- a Department of Microbiology and Immunology , University of South Alabama , Mobile , AL , USA
| | - Jarrod R Fortwendel
- b Department of Clinical Pharmacy , University of Tennessee Health Science Center , Memphis , TN , USA
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14
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Merino P, Maiuolo L, Delso I, Algieri V, De Nino A, Tejero T. Chemical approaches to inhibitors of isoprenoid biosynthesis: targeting farnesyl and geranylgeranyl pyrophosphate synthases. RSC Adv 2017. [DOI: 10.1039/c6ra28316k] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The chemical synthesis of farnesyl and geranylgeranyl pyrophosphate synthase inhibitors are surveyed.
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Affiliation(s)
- Pedro Merino
- Departamento de Síntesis y Estructura de Biomoléculas
- ISQCH
- Universidad de Zaragoza-CSIC
- 50009 Zaragoza
- Spain
| | - Loredana Maiuolo
- Dipartimento di Chimica
- Università della Calabria
- 87036 Rende
- Italy
| | - Ignacio Delso
- Departamento de Síntesis y Estructura de Biomoléculas
- ISQCH
- Universidad de Zaragoza-CSIC
- 50009 Zaragoza
- Spain
| | - Vincenzo Algieri
- Dipartimento di Chimica
- Università della Calabria
- 87036 Rende
- Italy
| | - Antonio De Nino
- Dipartimento di Chimica
- Università della Calabria
- 87036 Rende
- Italy
| | - Tomas Tejero
- Departamento de Síntesis y Estructura de Biomoléculas
- ISQCH
- Universidad de Zaragoza-CSIC
- 50009 Zaragoza
- Spain
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15
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Abstract
ABSTRACT
Invasive fungal infections are becoming an increasingly important cause of human mortality and morbidity, particularly for immunocompromised populations. The fungal pathogens
Candida albicans
,
Cryptococcus neoformans
, and
Aspergillus fumigatus
collectively contribute to over 1 million human deaths annually. Hence, the importance of safe and effective antifungal therapeutics for the practice of modern medicine has never been greater. Given that fungi are eukaryotes like their human host, the number of unique molecular targets that can be exploited for drug development remains limited. Only three classes of molecules are currently approved for the treatment of invasive mycoses. The efficacy of these agents is compromised by host toxicity, fungistatic activity, or the emergence of drug resistance in pathogen populations. Here we describe our current arsenal of antifungals and highlight current strategies that are being employed to improve the therapeutic safety and efficacy of these drugs. We discuss state-of-the-art approaches to discover novel chemical matter with antifungal activity and highlight some of the most promising new targets for antifungal drug development. We feature the benefits of combination therapy as a strategy to expand our current repertoire of antifungals and discuss the antifungal combinations that have shown the greatest potential for clinical development. Despite the paucity of new classes of antifungals that have come to market in recent years, it is clear that by leveraging innovative approaches to drug discovery and cultivating collaborations between academia and industry, there is great potential to bolster the antifungal armamentarium.
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Pianalto KM, Alspaugh JA. New Horizons in Antifungal Therapy. J Fungi (Basel) 2016; 2:jof2040026. [PMID: 29376943 PMCID: PMC5715934 DOI: 10.3390/jof2040026] [Citation(s) in RCA: 100] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Revised: 09/19/2016] [Accepted: 09/20/2016] [Indexed: 12/20/2022] Open
Abstract
Recent investigations have yielded both profound insights into the mechanisms required by pathogenic fungi for virulence within the human host, as well as novel potential targets for antifungal therapeutics. Some of these studies have resulted in the identification of novel compounds that act against these pathways and also demonstrate potent antifungal activity. However, considerable effort is required to move from pre-clinical compound testing to true clinical trials, a necessary step toward ultimately bringing new drugs to market. The rising incidence of invasive fungal infections mandates continued efforts to identify new strategies for antifungal therapy. Moreover, these life-threatening infections often occur in our most vulnerable patient populations. In addition to finding completely novel antifungal compounds, there is also a renewed effort to redirect existing drugs for use as antifungal agents. Several recent screens have identified potent antifungal activity in compounds previously indicated for other uses in humans. Together, the combined efforts of academic investigators and the pharmaceutical industry is resulting in exciting new possibilities for the treatment of invasive fungal infections.
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Affiliation(s)
- Kaila M Pianalto
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC 27710, USA.
| | - J Andrew Alspaugh
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC 27710, USA.
- Department of Medicine/Infectious Diseases, Duke University School of Medicine, Durham, NC 27710, USA.
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Al Abdallah Q, Fortwendel JR. Exploration of Aspergillus fumigatus Ras pathways for novel antifungal drug targets. Front Microbiol 2015; 6:128. [PMID: 25767465 PMCID: PMC4341556 DOI: 10.3389/fmicb.2015.00128] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 02/03/2015] [Indexed: 01/05/2023] Open
Abstract
Ras pathway signaling is a critical virulence determinant for pathogenic fungi. Localization of Ras to the plasma membrane (PM) is required for Ras network interactions supporting fungal growth and virulence. For example, loss of Aspergillus fumigatus RasA signaling at the PM via inhibition of palmitoylation leads to decreased growth, altered hyphal morphogenesis, decreased cell wall integrity and loss of virulence. In order to be properly localized and activated, Ras proteins must transit a series of post-translational modification (PTM) steps. These steps include farnesylation, proteolytic cleavage of terminal amino acids, carboxymethylation, and palmitoylation. Because Ras activation drives tumor development, Ras pathways have been extensively studied in mammalian cells as a potential target for anti-cancer therapy. Inhibitors of mammalian Ras interactions and PTM components have been, or are actively being, developed. This review will focus on the potential for building upon existing scaffolds to exploit fungal Ras proteins for therapy, synthesizing data from studies employing both mammalian and fungal systems.
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Affiliation(s)
- Qusai Al Abdallah
- Department of Microbiology and Immunology, University of South Alabama , Mobile, AL, USA
| | - Jarrod R Fortwendel
- Department of Microbiology and Immunology, University of South Alabama , Mobile, AL, USA
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Calderone R, Sun N, Gay-Andrieu F, Groutas W, Weerawarna P, Prasad S, Alex D, Li D. Antifungal drug discovery: the process and outcomes. Future Microbiol 2014; 9:791-805. [PMID: 25046525 PMCID: PMC4144029 DOI: 10.2217/fmb.14.32] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
New data suggest that the global incidence of several types of fungal diseases have traditionally been under-documented. Of these, mortality caused by invasive fungal infections remains disturbingly high, equal to or exceeding deaths caused by drug-resistant tuberculosis and malaria. It is clear that basic research on new antifungal drugs, vaccines and diagnostic tools is needed. In this review, we focus upon antifungal drug discovery including in vitro assays, compound libraries and approaches to target identification. Genome mining has made it possible to identify fungal-specific targets; however, new compounds to these targets are apparently not in the antimicrobial pipeline. We suggest that 'repurposing' compounds (off patent) might be a more immediate starting point. Furthermore, we examine the dogma on antifungal discovery and suggest that a major thrust in technologies such as structural biology, homology modeling and virtual imaging is needed to drive discovery.
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Affiliation(s)
| | - Nuo Sun
- National Institutes of Health, Bethesda, MD, USA
| | | | - William Groutas
- Department of Chemistry, Wichita State University, Wichita, KS, USA
| | | | | | - Deepu Alex
- Department of Pathology, MedStar, Georgetown University Medical Center, Washington, DC, USA
| | - Dongmei Li
- Georgetown University Medical Center, Washington, DC, USA
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